Solar cell and photovoltaic module

Abstract

Provided in the present application is a solar cell, comprising a cell body; a barrier layer arranged on the cell body; and a plurality of electrode structures arranged on the barrier layer, wherein each electrode structure comprises an organic layer and an electrode layer that are sequentially stacked, the electrode layer comprising an organic carrier and first metal particles, the organic material of the organic layer being the same as that of the organic carrier. Compared with the prior art where electrodes are formed on the barrier layer by screen printing, the provision of the organic layer between the barrier layer and the electrode layer can increase the bonding force between the barrier layer and the electrode layer, thereby improving the reliability of the solar cell. Using the same organic material enables a more secure bond between the organic layer and the electrode layer, thereby increasing the bonding force between the organic layer and the electrode layer, and improving the reliability of the solar cell. Further provided in the present application is a photovoltaic module comprising the described solar cell.

Description

Solar cells, photovoltaic modules

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 2025101209845, filed on January 24, 2025, entitled “Solar Cells, Photovoltaic Modules”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of solar cells, and more specifically, to a solar cell and a photovoltaic module including the solar cell. Background Technology

[0004] A solar cell is a device that converts solar energy into electrical energy using the photoelectric effect of semiconductor materials. In a solar cell, when sunlight shines on the semiconductor material, the atoms within the material undergo a transition reaction due to the influence of photons, forming electron-hole pairs. These pairs, under the influence of an electric field, generate a photovoltage. To utilize this photovoltage, electrodes are typically formed on P-type and N-type semiconductors. When electrons and holes accumulate on these semiconductors, they flow through these electrodes to an external circuit, forming a current, thus realizing the conversion of light energy into electrical energy.

[0005] Currently, conductive paste is typically printed directly using screen printing technology to form electrodes, thereby enabling the collection of electrons and holes. However, this method of directly printing conductive paste results in poor contact and weak adhesion between the electrodes and other structures in the solar cell, thus affecting the photoelectric conversion efficiency and reliability of the solar cell. Summary of the Invention

[0006] In view of this, this application provides a solar cell and a photovoltaic module to solve the above-mentioned problems existing in the prior art.

[0007] Specifically, according to a first aspect of this application, a solar cell is provided, comprising: a cell body; a barrier layer disposed on the cell body; and a plurality of electrode structures disposed on the barrier layer, wherein the electrode structures include an organic layer and an electrode layer stacked sequentially; wherein the electrode layer includes an organic carrier and a first metal particle, and the organic material of the organic layer is the same as the organic material of the organic carrier.

[0008] The solar cell provided in this application increases the bonding force between the barrier layer and the electrode layer by additionally setting an organic layer between them, preventing the electrode layer from detaching and improving the reliability of the solar cell. Furthermore, using the same organic material makes the bond between the organic layer and the electrode layer even stronger, thereby further improving the bonding force between the organic layer and the electrode layer and further enhancing the reliability of the solar cell.

[0009] In some implementations, the thickness of the organic layer is 1 nm to 50 nm.

[0010] In some embodiments, the organic layer includes a continuously extending continuous portion; wherein the length of the continuous portion ranges from 50 nm to 210 mm.

[0011] In some embodiments, the organic layer includes a continuously extending continuous portion; wherein the thickness of the continuous portion ranges from 3 nm to 50 nm.

[0012] In some implementations, the length of the continuous portion in the organic layer within a 5 μm length range accounts for 50% to 100%.

[0013] In some implementations, the thickness of at least one location in the organic layer is 1 nm to 5 nm.

[0014] In some implementations, the thickness of at least one location in the organic layer is 1 nm to 10 nm.

[0015] In some implementations, the width of the organic layer is greater than or equal to the width of the electrode layer.

[0016] In some implementations, the projection area of ​​the organic layer on the battery body completely covers the projection area of ​​the electrode layer on the battery body.

[0017] In some embodiments, at least a portion of the first metal particles in the electrode layer penetrate the organic layer and contact the barrier layer.

[0018] In some embodiments, the organic layer includes at least one conductive contact point within a 50 μm range, and the thickness of the organic layer at the conductive contact point is 1 nm-10 nm; or, a first metal particle in the electrode layer at the conductive contact point penetrates the organic layer and contacts the barrier layer.

[0019] In some implementations, the length of conductive contacts in the organic layer, within a 50 nm length range, accounts for 1% to 50% of the total length.

[0020] In some implementations, the ratio of the length of the conductive contact point to the width of the electrode structure ranges from 1% to 50% along the width direction of the electrode structure.

[0021] In some implementations, the organic layer is a conductive organic layer.

[0022] In some embodiments, the organic layer contains second metal particles with a smaller particle size than the first metal particles.

[0023] In some implementations, the organic material in the organic layer is a conductive organic material.

[0024] In some embodiments, the first metal particle includes sheet-like particles, which include monolayer sheet-like particles.

[0025] In some embodiments, the first metal particle includes a sheet-like particle whose outline is surrounded by a smooth curved surface.

[0026] In some embodiments, the first metal particle includes sheet-like particles and spherical particles, wherein the maximum size of the sheet-like particles ranges from 500 nm to 10 μm, and optionally, the maximum size of the sheet-like particles ranges from 500 nm to 4 μm.

[0027] In some embodiments, the first metal particle includes sheet-like particles and spherical particles, wherein the maximum size of the spherical particles ranges from 50 nm to 600 nm, or optionally, the maximum size of the spherical particles ranges from 50 nm to 400 nm.

[0028] In some embodiments, the first metal particle includes flake particles and spherical particles, wherein the mass ratio of flake particles to spherical particles is 5:5 to 8:2.

[0029] In some embodiments, the first metal particle includes sheet-like particles and spherical particles, wherein the projection of the sheet-like particles onto the barrier layer overlaps with the projection of the continuous portion onto the barrier layer.

[0030] In some embodiments, the first metal particle includes sheet-like particles and spherical particles, wherein at least one continuous portion exists in the organic layer in the range of 4 μm to 30 μm, and the length of the continuous portion is greater than or equal to the maximum size of the sheet-like particles.

[0031] In some implementations, the roughness of the barrier layer ranges from 1 nm to 300 nm within a 3 μm × 3 μm range.

[0032] In some embodiments, the electrode layer material includes at least one of copper paste, silver paste, silver-coated copper paste, aluminum paste, and aluminum-coated copper paste.

[0033] In some implementations, the barrier layer is an integral structure.

[0034] In some implementations, the barrier layer includes multiple sub-barrier layers, wherein an electrode structure is electrically connected to the multiple sub-barrier layers.

[0035] In some implementations, the barrier layer is a metal layer or a transparent conductive oxide layer.

[0036] In some embodiments, the battery body includes a semiconductor substrate and a doped semiconductor layer disposed on the semiconductor substrate, a barrier layer is in contact with the doped semiconductor layer, and an electrode structure is electrically connected to the doped semiconductor layer through the barrier layer.

[0037] In some embodiments, the battery body includes a semiconductor substrate and a doped semiconductor layer and a dielectric layer sequentially disposed on the semiconductor substrate. The dielectric layer has multiple openings, and a barrier layer is disposed for each opening. The barrier layer passes through the opening and contacts the doped semiconductor layer. The electrode structure is electrically connected to the doped semiconductor layer through the barrier layer.

[0038] In some embodiments, the projection of the electrode structure onto the semiconductor substrate covers at least a portion of the projection of the barrier layer and a portion of the dielectric layer onto the semiconductor substrate, and the organic layer in the electrode structure is also disposed between the electrode layer and the dielectric layer.

[0039] According to a second aspect of this application, a photovoltaic module is provided, comprising multiple battery strings, each battery string including multiple solar cells and multiple interconnects for connecting the multiple solar cells together in series; wherein the solar cells are the solar cells described in any one of the first aspects of this application. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other implementation schemes can be obtained based on these drawings without creative effort.

[0041] Figures 1a and 1b show schematic diagrams of the structure of solar cells according to some embodiments of this application.

[0042] Figure 2 shows a schematic diagram of the structure of a battery body according to some embodiments of this application.

[0043] Figure 3 shows a schematic diagram of the structure of a battery body according to some other embodiments of this application.

[0044] Figure 4 shows a schematic diagram of the structure of a solar cell according to some other embodiments of this application.

[0045] Figure 5 shows SEM images of the barrier layer, organic layer and electrode layer in a solar cell according to some embodiments of this application, and Figure 5B is an enlarged view of the boxed area in Figure 5A.

[0046] Figure 6 shows SEM images of the barrier layer, organic layer, and electrode layer in a solar cell according to some other embodiments of this application.

[0047] Figure 7 shows SEM images of the barrier layer, electrode layer and organic layer in a solar cell according to some embodiments of this application.

[0048] Figure 8 shows SEM images of the barrier layer, electrode layer, and organic layer in a solar cell containing a second metal particle within the organic layer, according to some embodiments of this application.

[0049] Figure 9 shows a schematic diagram of the structure of a solar cell with an integral barrier layer according to some embodiments of this application.

[0050] Figures 10 and 11 show schematic diagrams of the structure of a solar cell in which the barrier layer includes multiple sub-barrier layers, according to some embodiments of this application.

[0051] Figure 12 shows a schematic cross-sectional view of the electrode structure obtained along the width direction of the electrode structure in Figure 10 or Figure 11 and at the maximum length of the sub-blocking layer, according to some embodiments of this application.

[0052] Figure 13 shows a schematic diagram of the structure of a solar cell according to some embodiments of this application.

[0053] The reference numerals in the attached figures are as follows: 100 represents a solar cell; 10 represents the cell body; 101 represents a semiconductor substrate; 102 represents a doped semiconductor layer; 103 represents a dielectric layer; 104 represents an opening; 20 represents a barrier layer; 201 represents a sub-barrier layer; 30 represents an electrode structure; 301 represents an organic layer; and 302 represents an electrode layer. Detailed Implementation

[0054] The present application will now be clearly and completely described in conjunction with its embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all of them. All other embodiments that can be obtained by those skilled in the art based on the embodiments in this application are within the scope of protection of this application.

[0055] In this application, the terms "first" and "second" are used only to describe features for the purpose of description and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Features defined with "first" or "second" may explicitly or implicitly include at least one of the defined features. It is understood that "at least one" includes one or more, while "multiple" generally means at least two, such as two, three, four, five, six, etc., unless otherwise explicitly specified.

[0056] In this application, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can be a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0057] In this application, the terms "one embodiment," "some embodiments," "one example," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment, example, or example, which is included in at least one embodiment, example, or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment, example, or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments, examples, or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments, examples, or examples described in this specification, as well as the features of different embodiments, examples, or examples.

[0058] The photovoltaic module of this application includes a structure consisting of a transparent cover plate, an encapsulating film, a battery string, and an encapsulation backplate stacked together for photovoltaic power generation.

[0059] In photovoltaic (PV) modules, the transparent cover plate protects the internal solar cells and other materials from external environmental influences while maintaining high light transmittance to ensure effective solar energy absorption. It can be a transparent polymer film, such as ethylene-tetrafluoroethylene copolymer film, or transparent glass, such as ultra-clear photovoltaic glass. The encapsulating film is primarily used to bond the solar cell strings to the transparent cover plate and the encapsulation backsheet; it can be ethylene-octene copolymer (POE), ethylene-vinyl acetate copolymer (EVA), etc. The encapsulation backsheet, located on the outermost layer of the PV module's back, encapsulates and protects the solar cell strings from external environmental corrosion, providing weather resistance and insulation. It can be made of glass or organic polymer films. The solar cell strings convert solar energy into electrical energy and are the core component of the PV module.

[0060] Photovoltaic modules typically comprise multiple cell strings, which can be connected together in series and / or parallel. Each cell string includes multiple solar cells 100 and multiple interconnects for connecting the multiple solar cells in series. It is understood that the interconnects connect the multiple solar cells in series by electrically connecting them to the electrode structures of the multiple solar cells 100. Here, the solar cells 100 include any of the solar cells described below in this application. Furthermore, the aforementioned interconnects can be, for example, solder ribbons, metal wires, conductive tape, etc.

[0061] Figure 1 shows a schematic diagram of the structure of a solar cell 100 according to some embodiments of the present application. Referring to Figure 1, it can be seen that the solar cell 100 includes a cell body 10, a barrier layer 20 disposed on the cell body 10, and a plurality of electrode structures 30 disposed on the barrier layer 20.

[0062] Figure 2 shows a schematic diagram of the structure of a battery body 10 according to some embodiments of this application. Referring to Figure 2, it can be seen that the battery body 10 includes a semiconductor substrate 101 and a doped semiconductor layer 102 disposed on the semiconductor substrate 101. The semiconductor substrate 101 includes a first surface and a second surface opposite to each other, and the doped semiconductor layer 102 can be disposed on the first surface and / or the second surface of the semiconductor substrate 101. It can be seen that Figure 2 shows the case where the doped semiconductor layer 102 is disposed on only one surface of the semiconductor substrate 101. It is understood that the doped semiconductor layer 102 can also be disposed on both surfaces of the semiconductor substrate 101 simultaneously, and those skilled in the art can choose as needed. In this case, no dielectric layer is disposed between the doped semiconductor layer 102 and the barrier layer.

[0063] In some embodiments, the semiconductor substrate 101 includes a silicon substrate, a germanium substrate, a silicon-germanium substrate, etc. When the semiconductor substrate 101 is a silicon substrate, it can be monocrystalline silicon, polycrystalline silicon, amorphous silicon, microcrystalline silicon, etc., and this application does not limit it. In some embodiments, the material of the doped semiconductor layer 102 can be monocrystalline silicon, polycrystalline silicon, amorphous silicon, microcrystalline silicon, nanocrystalline silicon, etc., and this application does not limit it.

[0064] Figure 3 shows a schematic diagram of the battery body 10 according to some other embodiments of this application. Referring to Figure 3, it can be seen that the battery body 10 includes a semiconductor substrate 101, a doped semiconductor layer 102 and a dielectric layer 103 sequentially stacked on the semiconductor substrate 101, and the dielectric layer 103 has a plurality of openings 104. It can be seen that Figure 3 only shows the case where the doped semiconductor layer 102 and the dielectric layer 103 are stacked on only one surface of the semiconductor substrate 101. It is understood that the doped semiconductor layer 102 and the dielectric layer 103 can also be stacked on both surfaces of the semiconductor substrate 101 simultaneously, and those skilled in the art can choose as needed. In some embodiments, the material of the dielectric layer 103 can be one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, and amorphous silicon. Of course, other materials can also be used, and this application does not further limit them.

[0065] Furthermore, the dielectric layer 103 can be a single-layer structure or a multi-layer structure. In some examples, the dielectric layer 103 may include a passivation layer, or other possible layers such as an anti-reflection layer, or a passivation layer and an anti-reflection layer stacked together. The material of the passivation layer may be, for example, one or more of amorphous silicon and aluminum oxide, and the material of the anti-reflection layer may be, for example, one or more of silicon nitride, silicon oxide, and silicon oxynitride.

[0066] Referring again to Figure 1, the barrier layer 20 is disposed on the battery body 10. The barrier layer 20 protects the battery body 10 and reduces the risk of mechanical damage to the battery body 10 during the fabrication of the electrode structure 30. In some examples, the barrier layer 20 can also prevent some elements in the electrode structure 30 from diffusing into the battery body 10, affecting the photoelectric conversion efficiency of the solar cell 100. In other examples, the barrier layer 20 can also reduce the lateral transport resistance of charge carriers, improve the transport efficiency of charge carriers, and thus improve the photoelectric conversion efficiency.

[0067] In some examples, the barrier layer 20 can be a single, integral structure, as shown in Figures 1a and 1b. In this case, as shown in Figure 1a, one barrier layer 20 can be electrically connected to one electrode structure 30; or as shown in Figure 1b, one barrier layer 20 can be electrically connected to multiple electrode structures 30.

[0068] In other examples, the barrier layer 20 may also include multiple sub-barrier layers 201, i.e., multiple independent structures, wherein an electrode structure 30 is electrically connected to multiple sub-barrier layers 201, as shown in Figure 4.

[0069] Furthermore, the barrier layer 20 can be a metal layer or a transparent conductive oxide layer. The barrier layers with different structures and materials can be configured according to different types of solar cells.

[0070] Figure 9 shows a schematic diagram of the structure of a solar cell 100 with the barrier layer 20 integrally integrated according to some embodiments of this application. The solar cell 100 includes a cell body 10, which includes a semiconductor substrate 101 and a doped semiconductor layer 102 disposed on the semiconductor substrate 101. The barrier layer 20 is in contact with the doped semiconductor layer 102, and the electrode structure 30 is electrically connected to the doped semiconductor layer 102 through the barrier layer 20. In this embodiment, there is no dielectric layer between the barrier layer 20 and the doped semiconductor layer 102; the barrier layer 20 and the doped semiconductor layer 102 are in direct contact. In this embodiment, the barrier layer 20 may, for example, be a transparent conductive oxide layer.

[0071] Figures 10 and 11 illustrate schematic diagrams of the structure of a solar cell 100 according to some embodiments of this application, where the barrier layer 20 includes multiple sub-barrier layers 201. The solar cell 100 includes a cell body 10, which includes a semiconductor substrate 101 and a doped semiconductor layer 102 and a dielectric layer 103 sequentially disposed on the semiconductor substrate 101. The dielectric layer 103 has multiple openings 104, each opening 104 corresponding to a sub-barrier layer 201. The sub-barrier layer 201 passes through the opening 104 and contacts the doped semiconductor layer 102. The electrode structure 30 is electrically connected to the doped semiconductor layer 102 through the sub-barrier layer 201. In this embodiment, the sub-barrier layer 201 may be, for example, a transparent conductive oxide layer or a metal layer.

[0072] In cases where the barrier layer 20 includes multiple sub-barrier layers 201, in some embodiments, as shown in FIG10, the projection of the sub-barrier layer 201 onto the semiconductor substrate 101 overlaps with the projection of the opening 104, meaning that the sub-barrier layer 201 corresponding to the opening 104 does not extend over the dielectric layer 103. In other embodiments, as shown in FIG11, the sub-barrier layer 201 corresponding to the opening 104 extends onto the adjacent dielectric layer 103. When the sub-barrier layer 201 extends onto the dielectric layer 103, covering a portion of the surface of the dielectric layer 103 away from the semiconductor substrate 101, the surface of the dielectric layer 103 away from the semiconductor substrate 101 becomes rougher due to the sub-barrier layer 201 covering the dielectric layer 103, creating a rough interface and increasing the bonding force between the electrode structure 30 and the dielectric layer 103.

[0073] In some examples, the surface roughness of the sub-barrier layer 201 away from the semiconductor substrate 101 is greater than the surface roughness of the doped semiconductor layer 102 away from the semiconductor substrate 101. This arrangement can further increase the bonding force between the electrode structure 30 and the sub-barrier layer 201.

[0074] It should be noted that roughness refers to the difference between the highest and lowest points. When comparing roughness, the same area can be selected for roughness calculation.

[0075] Further, as shown in Figure 12, a cross-section is obtained along the width direction parallel to the electrode structure 30 and passing through the maximum length L1 of the sub-barrier layer 201. In this cross-section, the ratio of the maximum length L1 of the sub-barrier layer 201 to the sum of the lengths (L2+L3) of the two edge portions of the electrode structure 30 that contact the dielectric layer 103 is 0.1 to 0.9, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9. By controlling this ratio within the above range, it is possible to ensure both a small contact resistance between the sub-barrier layer 201 and the electrode structure 30 and a good bonding force between the electrode structure 30 and the dielectric layer 103, preventing the electrode structure 30 from detaching.

[0076] In some embodiments, as shown in FIG13, the projection of the electrode structure 30 on the semiconductor substrate 101 covers at least a portion of the projection of the barrier layer 20 and a portion of the dielectric layer 103 on the semiconductor substrate 101, and the organic layer 301 in the electrode structure 30 is also disposed between the electrode layer 302 and the dielectric layer 103.

[0077] Here, the projection of the electrode structure 30 onto the semiconductor substrate 101 can partially or completely cover the projection of the barrier layer 20 onto the semiconductor substrate 101. The organic layer 301 disposed between the electrode layer 302 and the dielectric layer 103 further increases the bonding force between the electrode layer 302 and the dielectric layer 103, further preventing the electrode layer 30 from detaching.

[0078] In this application, the solar cell 100 can be either a bifacial cell or a back-contact cell. When the solar cell 100 is a bifacial cell, it can be, for example, including but not limited to, a TOPCon cell, a heterojunction cell (HIT cell), or a bifacial hybrid cell. It is understood that when it is a bifacial cell, the barrier layer 20 and electrode structure 30 of this application can be disposed on either side or both sides of its cell body 10. When the solar cell 100 is a back-contact cell, it can be, for example, including but not limited to, a TBC cell, an HBC cell (heterojunction back-contact cell), or a hybrid back-contact cell. In some examples, the back-contact cell, such as a TBC cell, an HBC cell, or a hybrid back-contact cell, can be designed as an interdigitated back-contact cell (IBC cell). When the solar cell is a back-contact cell, the barrier layer 20 and electrode structure 30 of this application can be disposed on at least one of the P-region and N-region of the cell body 10.

[0079] In the case of a TOPCon solar cell 100, the cell body 10 includes a semiconductor substrate 101 and a tunneling layer (e.g., a tunneling oxide layer), a doped polycrystalline silicon layer (equivalent to a doped semiconductor layer 102), and a dielectric layer 103 sequentially stacked on the semiconductor substrate 101. The dielectric layer 103 has openings, and the electrode structure 30 is correspondingly disposed within these openings. In the TOPCon cell, the stacked tunneling layer and the doped polycrystalline silicon layer together constitute a passivation contact structure, which effectively reduces surface recombination and metal-to-metal recombination. In some examples, the semiconductor substrate 101 is an n-type silicon substrate, and the doped semiconductor layer 102 is an n-type doped polycrystalline silicon layer. In this case, the barrier layer 20 disposed on the cell body 10 can be a single, integral structure or can include multiple sub-barrier layers 201. When the barrier layer 20 is a single, integral structure, it can be, for example, a transparent conductive oxide (TCO) layer; when the barrier layer 20 includes multiple sub-barrier layers 201, it can be a TCO layer or a metal layer.

[0080] In the case where the solar cell 100 is a HIT cell, the cell body 10 includes a semiconductor substrate 101 and two doped semiconductor layers 102 respectively disposed on two opposite surfaces of the semiconductor substrate 101. These two doped semiconductor layers 102 have opposite doping types, i.e., one is n-type doped and the other is p-type doped. In this case, the material of the doped semiconductor layer 102 can be one or more of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. The HIT cell also includes an intrinsic amorphous silicon layer disposed between the semiconductor substrate 101 and the doped semiconductor layers 102. The intrinsic amorphous silicon layer has excellent passivation properties on the surface of the silicon substrate, which can significantly prevent carrier recombination and achieve higher minority carrier lifetime and open-circuit voltage. In this case, the barrier layer 20 disposed on the cell body 10 is an integral structure, and the barrier layer 20 can be, for example, a TCO layer.

[0081] In the case where the solar cell 100 is a bifacial hybrid cell, the cell body 10 includes a semiconductor substrate 101, a tunneling layer (e.g., a tunneling oxide layer), a doped polycrystalline silicon layer (equivalent to a first doped semiconductor layer 102), and a dielectric layer 103 sequentially stacked on a first surface of the semiconductor substrate 101, and an intrinsic amorphous silicon layer and a second doped semiconductor layer sequentially stacked on a second surface opposite to the first surface. The material of the second doped semiconductor layer can be one or more of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. The doped polycrystalline silicon layer and the second doped semiconductor layer have opposite conductivity types, i.e., one is n-type doped and the other is p-type doped. The tunneling layer and the doped polycrystalline silicon layer can be disposed in a local area or the entire area of ​​the first surface. The doped semiconductor layer can include at least one of the first doped semiconductor layer 102 and the second doped semiconductor layer. In this case, the barrier layers 20 disposed on both sides of the battery body 10 can be a single integrated structure; alternatively, the barrier layer 20 on the side with the intrinsic amorphous silicon layer and the doped semiconductor layer 102 can be a single integrated structure, while the barrier layer 20 on the side with the tunneling layer and the doped polycrystalline silicon layer includes multiple sub-barrier layers 201, which are disposed together with the electrode structure 30 corresponding to the opening 104 of the dielectric layer 103. When the barrier layer 20 is a single integrated structure, the barrier layer 20 can be a TCO layer; when it includes multiple sub-barrier layers 201, the barrier layer 20 can be a TCO layer or a metal layer.

[0082] When the solar cell 100 is an HBC cell, the cell body 10 includes a semiconductor substrate 101, which includes P-regions and N-regions alternately disposed in sequence. The cell body 10 includes a first intrinsic amorphous silicon layer and a P-type doped semiconductor layer disposed in sequence in the P-region, and a second intrinsic amorphous silicon layer and an N-type doped semiconductor layer disposed in sequence in the N-region. The doped semiconductor layer 102 includes at least one of a P-type doped semiconductor layer and an N-type doped semiconductor layer. The materials of the P-type doped semiconductor layer and the N-type doped semiconductor layer can be one or more of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. In some examples, the semiconductor substrate 101 also includes an overlapping region disposed between the P-region and the N-region. The first intrinsic amorphous silicon layer, the P-type doped semiconductor layer, the second intrinsic amorphous silicon layer, and the N-type doped semiconductor layer are stacked in sequence in the overlapping region. The second intrinsic amorphous silicon layer and the N-type doped semiconductor layer can be disposed on the first intrinsic amorphous silicon layer and the P-type doped semiconductor layer, or the first intrinsic amorphous silicon layer and the P-type doped semiconductor layer can be disposed on the second intrinsic amorphous silicon layer and the N-type doped semiconductor layer. Electrode structures 30 are respectively provided in the P-region and N-region. HBC cells help improve carrier lifetime and reduce surface recombination. In this case, the barrier layer 20 provided on the doped semiconductor layer 102 of the cell body 10 includes a plurality of sub-barrier layers 201, each sub-barrier layer 201 corresponding to a P-region or an N-region, wherein the plurality of sub-barrier layers 201 correspond one-to-one with a plurality of electrode structures 30, and the barrier layer 20 can be a TCO layer.

[0083] When the solar cell 100 is a TBC cell, the cell body 10 includes a semiconductor substrate 101, which includes P-regions and N-regions alternately disposed in sequence. The cell body 10 includes a tunneling layer (e.g., a tunneling oxide layer) and a P-type doped polysilicon layer disposed in sequence in the P-region, and a tunneling layer and an N-type doped polysilicon layer disposed in sequence in the N-region. The doped semiconductor layer 102 includes at least one of the P-type doped polysilicon layer and the N-type doped polysilicon layer. The cell body 10 also includes a dielectric layer 103 disposed on the P-type doped polysilicon layer and the N-type doped semiconductor layer. A sub-barrier layer 201 is disposed together with the electrode structure 30 corresponding to the opening 104 of the dielectric layer 103, and the sub-barrier layer 201 is in contact with the doped semiconductor layer 102. In some examples, the semiconductor substrate 101 also includes an isolation region disposed between the P-region and the N-region, which may be, for example, an isolation trench. Electrode structures 30 are disposed in the P-region and the N-region, respectively. In this case, the barrier layer 20 disposed on the doped semiconductor layer 102 of the battery body 10 includes a plurality of sub-barrier layers 201, wherein the plurality of sub-barrier layers 201 may correspond one-to-one with a plurality of electrode structures 30, or one electrode structure 30 may be disposed in correspondence with a plurality of sub-barrier layers 201. The barrier layer 20 may be a metal layer or a TCO layer.

[0084] In the case where the solar cell 100 is a hybrid back-contact cell, the cell body 10 includes a semiconductor substrate 101 and alternating tunneling passivation contact structures and heterojunction contact structures disposed on the semiconductor substrate 101. The tunneling passivation contact structure includes a stacked tunneling layer (e.g., a tunneling oxide layer) and a doped polycrystalline silicon layer (equivalent to a first doped semiconductor layer). The heterojunction contact structure includes a stacked intrinsic amorphous silicon layer and a second doped semiconductor layer. The doped semiconductor layer 102 includes at least one of the first and second doped semiconductor layers. The material of the second doped semiconductor layer can be one or more of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. The doped polycrystalline silicon layer and the second doped semiconductor layer have opposite conductivity types, i.e., one is n-type doped and the other is p-type doped. In some examples, the heterojunction contact structure extends and overlaps on a portion of the tunneling passivation contact structure. In this case, the barrier layer 20 disposed on the doped semiconductor layer 102 of the battery body 10 includes a plurality of sub-barrier layers 201, wherein the plurality of sub-barrier layers 201 correspond one-to-one with a plurality of electrode structures 30, and the barrier layer 20 can be a TCO layer.

[0085] It can be understood that n-type silicon substrate, n-type doped layer, or n-type doping refers to doping using dopants containing group V elements such as P and As, which are used to provide electrons after doping. p-type silicon substrate, p-type doped layer, or p-type doping refers to doping using dopants containing group III elements such as B and Al, which are used to provide holes after doping.

[0086] In this application, the solar cell 100 can be any of the above-mentioned types of cells.

[0087] In some embodiments, the material of the transparent conductive oxide layer includes one or more combinations of indium tin oxide (ITO), indium tungsten oxide (IWO), and indium titanium oxide (ITiO). Of course, other materials can also be used, and this application does not further limit their application. The transparent conductive oxide layer not only facilitates the collection of charge carriers in the doped semiconductor layer 102 but also provides a certain degree of anti-reflection effect.

[0088] In some embodiments, the material of the metal layer includes one or a combination of nickel, silver, tin, and aluminum. Of course, other materials may also be used, and this application does not further limit them.

[0089] Referring again to Figure 1, multiple electrode structures 30 are disposed on the barrier layer 20, and each electrode structure 30 includes an organic layer 301 and an electrode layer 302 stacked sequentially. Compared to the prior art where the barrier layer 20 is directly formed on the electrode layer 302, i.e., without an organic layer 301 between the barrier layer 20 and the electrode layer 302, the presence of an additional organic layer 301 between the barrier layer 20 and the electrode layer 302 increases the bonding force between them, thereby improving the reliability of the solar cell 100. Figure 5 shows SEM images of the barrier layer 20, organic layer 301, and electrode layer 302 in a solar cell according to some embodiments of this application, where the barrier layer 20 is a TCO layer. Figure 6 shows SEM images of the barrier layer 20, organic layer 301, and electrode layer 302 in a solar cell according to some embodiments of this application, where the barrier layer 20 is a metal layer.

[0090] In some embodiments, the material of electrode layer 302 can be silver paste, copper paste, silver-coated copper paste, aluminum paste, aluminum-coated copper paste, etc. Further, the material of electrode layer 302 includes at least one of copper paste, silver paste, silver-coated copper paste, aluminum paste, and aluminum-coated copper paste.

[0091] In one specific example, the material of the barrier layer 20 includes TCO, and the material of the electrode layer 302 includes copper paste or silver-coated copper paste. In another specific example, the material of the barrier layer 20 includes high-temperature silver paste, and the material of the electrode layer 302 includes copper paste or silver-coated copper paste. In yet another specific example, the material of the barrier layer 20 includes nickel, and the material of the electrode layer 302 includes copper paste or silver-coated copper paste.

[0092] In this application, electrode layer 302 includes an organic carrier and first metal particles, i.e., electrode layer 302 is a slurry layer. The organic carrier of electrode layer 302 can be any commonly used organic material known in the art for forming slurries, typically including, for example, resin, curing accelerator, and other additives such as dispersants and coupling agents; the resin can be selected from epoxy resins such as glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, alicyclic epoxy resin, etc., polyurethane resin, polyester resin, phenolic resin, phenoxy resin, and one or more combinations thereof; the curing accelerator is selected from amine curing accelerators, acid curing accelerators, and quaternary ammonium salt curing accelerators. Those skilled in the art can choose the specific type as needed, and this application does not limit this selection. It is understood that the above-mentioned organic materials are generally non-conductive, but they can be made conductive by modifying the organic materials or adding conductive fillers (e.g., graphene, carbon nanotubes, carbon black, nano-metals and their oxides). The first metal particles filled in the organic carrier in electrode layer 302 form a conductive network, thus achieving conductivity. In some embodiments, the material of the first metal particle may include copper, silver, nickel, aluminum, their alloys, or any combination thereof, wherein the alloy may be a copper-silver alloy, a copper-nickel alloy, a silver-nickel alloy, a silver-aluminum alloy, etc. It is understood that the materials of the organic carrier and the first metal particle described above are merely exemplary, and those skilled in the art may use other materials to form the electrode layer 302; this application does not further limit this.

[0093] In some embodiments, the first metal particle can be at least one of spherical particles and sheet-like particles. Such first metal particles can form a conductive network in the electrode layer 302, improving the conductivity of the electrode layer 302 and increasing the carrier collection efficiency. Here, the size of the spherical particles ranges from 50 nm to 1.5 μm, for example, 50 nm, 60 nm, 100 nm, 150 nm, 200 nm, 300 nm, 500 nm, 1 μm, or 1.5 μm. This size range ensures good conductivity in the electrode layer 302. The size of the sheet-like particles ranges from 500 nm to 6 μm, for example, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, or 6 μm. This size range also ensures good conductivity in the electrode layer 302.

[0094] In some examples, the first metal particle described above includes sheet-like particles, which in turn include monolayer sheet-like particles. Because the sheet-like particles are monolayer sheet-like particles, a greater number of these particles are dispersed in the electrode layer, which is more beneficial for improving the conductivity of the electrode layer 302. Compared to multilayer sheet-like particles, monolayer sheet-like particles have a smoother surface.

[0095] In other examples, the sheet-like particles include multilayer sheet-like particles, that is, sheet-like particles formed by stacking multiple sheets. In this case, the sheet-like particles have lower resistance.

[0096] In some examples, the first metal particle described above includes plate-like particles whose outlines are enclosed by smooth curved surfaces. Here, the outline of the plate-like particles can refer to the outer outline of the plate-like particles as observed from any viewing angle when examined under an electron microscope (e.g., a scanning electron microscope). Because the outline of the plate-like particles is enclosed by smooth curved surfaces, the uniformity of the first metal particles in the electrode layer can be improved, thereby improving the conductivity of the electrode layer.

[0097] It should be noted that the first metal particle can be formed by the accumulation of at least one of metal ions and metal atoms.

[0098] In some embodiments, the first metal particles include sheet-like particles and spherical particles, wherein the maximum size range of the sheet-like particles is 500 nm to 10 μm. In some examples, the maximum size range of the sheet-like particles is 500 nm to 4 μm, such as 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, and 4 μm. When the first metal particles include sheet-like particles and spherical particles, controlling the maximum size range of the sheet-like particles within the above-mentioned range can further improve the adhesion between the electrode layer 302 and the organic layer 301 while ensuring the conductivity of the electrode layer 302.

[0099] In some embodiments, the first metal particles include sheet-like particles and spherical particles, wherein the maximum size range of the spherical particles is 50 nm to 600 nm, for example, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, and 600 nm. When the first metal particles include both sheet-like and spherical particles, controlling the maximum size range of the spherical particles within the aforementioned range can further improve the conductivity of the electrode layer 302 and enhance the carrier collection efficiency while ensuring a strong bond between the electrode layer 302 and the organic layer 301.

[0100] It should be noted that due to process errors, the maximum size of individual flake particles or individual spherical particles may not be within the above-mentioned size range. However, as long as the maximum size of most flake particles or spherical particles is within the above-mentioned size range, they are within the scope of protection of this application.

[0101] In some embodiments, the first metal particles include sheet-like particles and spherical particles, wherein the mass ratio of sheet-like particles to spherical particles is 5:5 to 8:2. Controlling the mass ratio of sheet-like particles to spherical particles within the above range can further improve the bonding force between the electrode layer 302 and the organic layer 301, while also improving the conductivity of the electrode layer 302 and increasing the carrier collection efficiency.

[0102] In this application, the organic material of the organic layer 301 is the same as the organic material of the organic carrier of the electrode layer 302. Using the same organic material makes the bond between the organic layer 301 and the electrode layer 302 stronger, thereby improving the bonding force between the organic layer 301 and the electrode layer 302 and improving the reliability of the solar cell 100.

[0103] It is understandable that the organic layer 301 can be formed separately from the electrode layer 302, for example, the organic layer 301 can be formed first, and then the electrode layer 302 can be formed; the organic layer 301 can also be formed simultaneously with the electrode layer 302. In the case of simultaneous formation, during the formation of the electrode layer 302, by controlling the curing process conditions, the composition of the slurry, and the roughness of the barrier layer 20, the organic material in the electrode layer 302 can be formed between the electrode layer 302 and the barrier layer 20, thereby forming the organic layer 301. This not only simplifies the process, but also allows the organic material of the organic layer 301 to be connected with the organic material of the organic carrier of the electrode layer 302 to form an integrated structure, which is more conducive to increasing the bonding force between the electrode layer 302 and the barrier layer 20.

[0104] It should be noted that during the formation of the electrode layer, the formation of an organic layer between the electrode layer and the barrier layer can be controlled by adjusting the slurry curing process conditions (e.g., curing temperature and time), the slurry composition (e.g., the proportion of organic components, the proportion of spherical particles, the proportion of flake particles, the size of spherical particles, and the size of flake particles), and the roughness of the barrier layer. Specifically, a higher proportion of organic components in the slurry is more conducive to the accumulation of organic matter between the electrode layer and the barrier layer, thus forming an organic layer. During slurry printing, due to printing processes, the extension direction of the flake particles is parallel or nearly parallel to the printing substrate (i.e., the barrier layer), making it easier for the organic matter beneath the flake particles to form an organic layer. Therefore, compared to spherical particles, flake particles are more likely to form an organic layer between themselves and the barrier layer, and a larger proportion of flake particles is more conducive to the formation of an organic layer. Furthermore, larger flake particle sizes are also more conducive to the formation of an organic layer. The lower the curing temperature and the shorter the curing time of the slurry, the less organic matter near the barrier layer volatilizes, which is more conducive to the formation of an organic layer. Conversely, if the roughness of the barrier layer is too high, flaky or spherical particles are more likely to form between the protruding structures of the barrier layer, which is detrimental to the formation of the organic layer. Based on this, and referring to the above, by adjusting the curing temperature and time of the slurry, the proportion of spherical particles, the proportion of flaky particles, the size of the spherical particles, the size of the flaky particles, and the roughness of the barrier layer, the formation of an organic layer can be adjusted. Furthermore, the length and thickness of the formed organic layer, the length and thickness of the continuous portions within the organic layer, and the length of the conductive contact points within the organic layer can be adjusted to ensure excellent bonding performance between the barrier layer and the electrode layer, while also ensuring excellent conductivity in both.

[0105] In some embodiments, the curing temperature is 150°C to 280°C, for example, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, or 280°C. In some embodiments, the curing time is 5 min to 20 min, for example, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, or 20 min. Controlling the curing temperature and / or time within the above ranges is beneficial for forming an organic layer 301 with excellent bonding properties and ensures the conductivity between the barrier layer 20 and the electrode layer 302.

[0106] In some implementations, the roughness of the barrier layer 20 ranges from 1 nm to 300 nm within a 3 μm × 3 μm area, for example, 1 nm, 10 nm, 30 nm, 50 nm, 70 nm, 90 nm, 110 nm, 130 nm, 150 nm, 170 nm, 190 nm, 210 nm, 230 nm, 250 nm, 270 nm, 290 nm, and 300 nm. Controlling the roughness range of the barrier layer 20 within the above range is beneficial for the formation of the organic layer 301.

[0107] Furthermore, when the barrier layer 20 is a transparent conductive oxide layer, the roughness of the barrier layer 20 within a 3μm × 3μm range is 20nm to 160nm, for example, 20nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, and 160nm. Controlling the roughness range of the transparent conductive oxide layer serving as the barrier layer 20 within the above range is beneficial to the formation of the organic layer 301, improves the bonding force between the barrier layer 20 and the electrode layer, and allows for the control of the length and thickness of the organic layer 301, while also taking into account the formation process of the transparent conductive oxide layer.

[0108] Furthermore, when the barrier layer 20 is a metal layer, within a 3μm × 3μm range, the roughness of the barrier layer 20 within the opening of the dielectric layer ranges from 1nm to 300nm, for example, 1nm, 10nm, 30nm, 50nm, 70nm, 90nm, 110nm, 130nm, 150nm, 170nm, 190nm, 210nm, 230nm, 250nm, 270nm, 290nm, and 300nm. Controlling the roughness range of the metal layer serving as the barrier layer 20 within the above range is beneficial for the formation of the organic layer 301, improves the bonding force between the barrier layer 20 and the electrode layer, and allows for the control of the length and thickness of the organic layer 301, while also taking into account the formation process of the metal layer.

[0109] In some implementations, the roughness of the dielectric layer 103 ranges from 1 nm to 300 nm within a 3 μm × 3 μm area, for example, 1 nm, 10 nm, 30 nm, 50 nm, 70 nm, 90 nm, 110 nm, 130 nm, 150 nm, 170 nm, 190 nm, 210 nm, 230 nm, 250 nm, 270 nm, 290 nm, and 300 nm. Controlling the roughness range of the dielectric layer 103 within the above range is beneficial for forming the organic layer 301 between the dielectric layer and the electrode layer, ensuring the bonding force between the dielectric layer and the electrode layer, and also allowing for the control of the length, thickness, etc., of the organic layer 301.

[0110] It should be noted that the thickness, dimensions, roughness, etc., mentioned in this application can be measured using methods and instruments commonly used in the field, and the corresponding values ​​can refer to a single measured value or the average of multiple measured values. This application does not impose any specific limitations in this regard.

[0111] In some implementations, the thickness of the organic layer 301 is 1nm-50nm, for example, the thickness of the organic layer 301 can be 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 15nm, 18nm, 19nm, 20nm, 25nm, 30nm, 40nm, or 50nm. If the thickness of the organic layer 301 is too small, it cannot firmly bond the electrode layer 302 and the barrier layer 20. If the thickness is too large, it will result in an excessively high bulk resistance of the organic layer 301, affecting the collection of charge carriers and thus affecting the photoelectric conversion efficiency of the solar cell 100. Controlling the thickness of the organic layer 301 within the above range not only ensures that the organic layer 301 can firmly bond the electrode layer 302 and the barrier layer 20, but also prevents the bulk resistance of the organic layer 301 from becoming too high, thus ensuring efficient collection of charge carriers.

[0112] It is understandable that the thickness of the organic layer 301 can be uniform or non-uniform. When the thickness of the organic layer 301 is non-uniform, in this case, the thickness of the organic layer 301 is 1nm-50nm, meaning that the thickness at any location in the organic layer 301 is within the thickness range of the organic layer 301 (1nm-50nm). Of course, in some examples, it can also mean that the thickness at any location in the organic layer 301 is within the range of the organic layer 301 (1nm-50nm).

[0113] In some embodiments, the organic layer 301 includes a continuously extending continuous portion, as shown in the box in FIG6. The continuous portion in the organic layer 301 is primarily used to enhance the bonding force between the electrode layer 302 and the barrier layer 20.

[0114] Further, optionally, the length of the continuous portion ranges from 50nm to 210mm, for example, 50nm, 150nm, 250nm, 350nm, 450nm, 550nm, 650nm, 750nm, 850nm, 950nm, 1μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, 1mm, 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, and 210mm. In some examples, the length of the continuous portion in the width direction of the electrode structure 30 ranges from 50 nm to 400 μm. In some examples, the length of the continuous portion in the length direction of the electrode structure 30 ranges from 50 nm to 210 mm. Considering that a longer continuous portion in the organic layer 301 results in a stronger bond between the electrode layer 302 and the barrier layer 20, but a larger continuous portion length would lead to a higher resistance in the electrode layer 302, setting the length of the continuous portion within the range of 50 nm to 210 mm achieves an optimal balance between bond strength and conductivity.

[0115] Further, optionally, the thickness of the continuous portion ranges from 3nm to 50nm, for example, 3nm, 5nm, 8nm, 10nm, 13nm, 15nm, 18nm, 20nm, 23nm, 25nm, 28nm, 30nm, 33nm, 35nm, 38nm, 40nm, 43nm, 45nm, 48nm, and 50nm. The effect of setting the thickness of the continuous portion within the above range is similar to the effect of setting the length of the continuous portion within the range of 50nm to 210mm, and will not be repeated here. It should be noted that when the thickness of the continuous portion is in the range of 3nm to 50nm, the continuous portion can both improve the bonding force between the electrode layer 302 and the barrier layer 20, and facilitate the transport of charge carriers from the barrier layer 20 to the electrode layer 302. When the thickness of the continuous portion is greater than 50nm, the effect of improving the bonding force between the electrode layer 302 and the barrier layer 20 is more pronounced.

[0116] In some embodiments, the length percentage of the continuous portion within a 5 μm length range of the organic layer 301 is 50% to 100%, for example, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%. Here, the 5 μm length range of the organic layer 301 can be along the width direction or the length direction of the electrode layer 302. Setting the length percentage of the continuous portion within this range further ensures a strong bond between the electrode layer 302 and the barrier layer 20.

[0117] In some embodiments, the first metal particles include sheet-like particles and spherical particles, wherein the projection of the sheet-like particles onto the barrier layer 20 overlaps with the projection of the continuous portion onto the barrier layer 20. That is, a continuous portion is formed between the sheet-like particles and the barrier layer 20. Since the sheet-like particles are typically larger and easier to detach, forming a continuous portion between the sheet-like particles and the barrier layer 20 helps increase the bonding force between the sheet-like particles and the barrier layer 20, thereby effectively increasing the bonding force between the electrode layer 302 and the barrier layer 20.

[0118] In some embodiments, the first metal particles include sheet-like particles and spherical particles, wherein at least one continuous portion exists in the organic layer 301 within the range of 4μm to 30μm, for example, within the ranges of 4μm, 10μm, 15μm, 20μm, 25μm, and 30μm, and the length of the continuous portion is greater than or equal to the maximum size of the sheet-like particles. This arrangement further ensures a strong bond between the electrode layer 302 and the barrier layer 20.

[0119] To achieve electrical connection between electrode layer 302 and barrier layer 20, ensuring low contact resistance and strong adhesion between them, this application can adjust the thickness and material of organic layer 301, electrode layer 302, etc. Examples are provided below. It is understood that the following embodiments for achieving electrical connection between electrode layer 302 and barrier layer 20 can be used individually or in combination.

[0120] In some embodiments, the thickness of at least one location in the organic layer 301 is 1nm-5nm, for example, 1nm, 2nm, 3nm, 4nm, or 5nm. In other embodiments, the thickness of at least one location in the organic layer is 1nm-10nm, for example, 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, or 10nm. It is understood that the thickness of one or more locations in the organic layer 301 can be in the range of 1nm-5nm, or in the range of 1nm-10nm; or the thickness of any location in the organic layer 301 can be in the range of 1nm-5nm, or in the range of 1nm-10nm. A thinner organic layer 301 can achieve conductivity through a tunneling mechanism; therefore, even when the organic layer 301 itself is not conductive, such a thickness of organic layer 301 can still electrically connect the electrode layer 302 to the barrier layer 20. The organic material of the organic layer 301 is the same as the aforementioned organic material of the electrode layer 302. Figure 7 shows SEM images of the barrier layer 20, electrode layer 302, and organic layer 301 in a solar cell 100 according to some embodiments of this application. As can be seen from Figure 7, the thickness of the organic layer 301 is approximately 3.5 nm. Due to the relatively small thickness of the organic layer 301, charge carriers can tunnel through the organic layer 301 to achieve electrical connection between the electrode layer 301 and the barrier layer 20. In this case, the organic material in the organic layer 301 can be conductive or non-conductive.

[0121] It is understood that in some embodiments, the organic layer 301 itself has conductive properties, i.e., it is a conductive organic layer, to electrically connect the electrode layer 302 and the barrier layer 20. In this case, the thickness of the organic layer 301 is not limited.

[0122] To enable the organic layer 301 to possess conductive properties, it can be achieved through at least one of the following two methods: Firstly, the organic layer 301 can contain second metal particles, meaning the second metal particles in the organic layer 301 are filled within the organic material. The second metal particles form a conductive network within the organic layer 301, thus achieving conductivity. Here, the second metal particles can be formed by the accumulation of at least one of metal ions or metal atoms. Secondly, the organic material of the organic layer 301 can be a conductive organic material, achieving conductivity through the use of a conductive organic material. The organic material of the organic layer 301 is the same as the aforementioned organic material of the electrode layer 302. Figure 8 shows SEM images of the barrier layer 20, electrode layer 302, and organic layer 301 in a solar cell 100 according to some embodiments of this application, where the barrier layer 20 is a metal layer, and the organic layer 301 contains second metal particles.

[0123] In some embodiments, the particle size of the second metal particle is smaller than that of the first metal particle. In some embodiments, the second metal particle is a nanoscale metal particle, which makes it easier for the metal particle to disperse in the organic layer 301. Optionally, the particle size of the second metal particle is 1nm-20nm, for example, 1nm, 3nm, 5nm, 10nm, 15nm, or 20nm. As can also be seen from Figure 8, in some examples, the second metal particles contained in the conductive organic layer 301 are nanoscale metal particles. Optionally, the particle size of the second metal particle is less than 10nm.

[0124] In some embodiments, the second metal particle may be made of the same or different material as the first metal particle. In some embodiments, the material of the second metal particle may be copper, silver, nickel, aluminum, their alloys, or any combination thereof, wherein the alloy may be a copper-silver alloy, a copper-nickel alloy, a silver-nickel alloy, a silver-aluminum alloy, etc. It is understood that the materials of the second metal particles described above are merely exemplary, and those skilled in the art may use other metallic materials; this application does not further limit their use.

[0125] In some other embodiments, as shown in FIG6, at least a portion of the first metal particles in the electrode layer 302 penetrate the organic layer 301 and contact the barrier layer 20 (e.g., at the location indicated by the arrow in FIG6), thereby achieving an electrical connection between the electrode layer 302 and the barrier layer 301. It should be noted that when the thickness of the organic layer 301 between the electrode layer 302 and the barrier layer 20 is less than 1 nm, it can be considered that there is no organic layer 301 between the electrode layer 302 and the barrier layer 20, and the first metal particles directly penetrate the organic layer 301 and contact the barrier layer 20.

[0126] To ensure that the transport resistance of charge carriers passing through the organic layer 301 is not too high, and to ensure that the bonding force between the electrode layer 302 and the barrier layer 20 through the organic layer 301 is sufficient, in some examples, the organic layer 301 includes at least one conductive contact point within a 50 μm range. Here, including at least one conductive contact point within a 50 μm range in the organic layer 301 can be along the width direction of the electrode layer 302 or along the length direction of the electrode layer 302. Furthermore, including at least one conductive contact point within a 50 μm range in the organic layer 301 can be one, two, or more conductive contact points.

[0127] Here, in order to reduce the transmission resistance of charge carriers when passing through the organic layer 301, at least one conductive contact point may be included in the range of 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, etc.

[0128] In some embodiments, the thickness of the organic layer 301 at the conductive contact point is 1 nm to 10 nm. Further, to further reduce the carrier transport resistance, the thickness of the organic layer 301 at the conductive contact point is 1 nm to 5 nm. In this case, the organic layer 301 achieves conductivity through a tunneling mechanism. When the thickness of the organic layer 301 at the conductive contact point is other thicknesses where conductivity cannot be achieved through a tunneling mechanism, conductivity can be achieved through other methods described herein, such as including conductive metal particles, or other methods known in the art.

[0129] In other embodiments, the first metal particle in the electrode layer 302 at the conductive contact point passes through the organic layer 301 and contacts the barrier layer 20. In this case, the organic layer 301 can achieve the conductive function through the metal particle.

[0130] To further ensure that the transmission resistance of charge carriers through the organic layer 301 is not too high, and to ensure that the bonding force between the electrode layer 302 and the barrier layer 20 through the organic layer 301 is sufficient, it is necessary to further control the proportion of the length of the conductive contact point in the total or part of the length range of the organic layer 301.

[0131] In this document, "the entire or part of the length range of the organic layer 301" can refer to the entire or part of the length range of the organic layer 301 along the width direction of the electrode layer 302 or along the length direction of the electrode layer 302. "The length of the conductive contact point" refers to the length of the contact surface of all conductive contact points that contact the barrier layer 20 in the same direction along a cross-section of the organic layer 301 in the width or length direction.

[0132] In this application, the length percentage of conductive contact points within a 50nm length range in the organic layer 301 can be either along the width direction of the electrode layer 302 or along the length direction of the electrode layer 302, representing the length percentage of all conductive contact points within a 50nm length range of the organic layer 301. In some embodiments, the length percentage of conductive contact points within a 50nm length range in the organic layer can be 1% to 50%, for example, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%. Setting the length percentage of conductive contact points within a 50nm length range in the organic layer 301 within the above range can further ensure efficient carrier collection while maintaining bonding strength.

[0133] Furthermore, along the width direction of the electrode layer 302, the ratio of the length of the conductive contact point to the width of the electrode layer 302 can range from 1% to 50%, for example, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%. Setting this ratio within the above range can further improve the conductivity of the organic layer 301 and ensure efficient collection of charge carriers from the barrier layer to the electrode layer.

[0134] In some embodiments, the width of the organic layer 301 is greater than or equal to the width of the electrode layer 302. By controlling any width of the organic layer 301 to be greater than or equal to any width of the electrode layer 302, it can be ensured that any position in the electrode layer 302 can be electrically connected to the barrier layer 20 through the organic layer 301, further increasing the bonding force between the electrode structure 30 and the barrier layer 20, thereby preventing the electrode structure 30 from falling off.

[0135] Furthermore, along the width direction of the electrode layer 302, the portion of the organic layer 301 extending beyond the electrode layer 302 contains a small amount of metal particles. Furthermore, the metal particles are spherical. The metal particles in the portion of the organic layer 301 extending beyond the electrode layer 302 can reduce the transport resistance of charge carriers passing through the organic layer 301.

[0136] In some embodiments, the projection area of ​​the organic layer 301 on the surface of the battery body 10 completely covers the projection area of ​​the electrode layer 302 on the surface of the battery body 10. That is, when both the organic layer 301 and the electrode layer 302 are projected onto the battery body 10, only the projection area of ​​the organic layer 301 is visible. It can be understood that "complete coverage" includes two situations: one is that the projection area of ​​the organic layer 301 is larger than the projection area of ​​the electrode layer 302, and the other is that the projection areas of the organic layer 301 and the electrode layer 302 overlap. The beneficial effect of the width of the organic layer 301 being greater than or equal to the width of the electrode layer 302 can be referred to above, and will not be elaborated further here.

[0137] On the production line, a copper paste is printed on a transparent conductive oxide layer (barrier layer). The copper paste includes first metal particles and organic components. The proportion of the first metal particles in the copper paste is 85% to 90%. The proportion of organic components in the copper paste is 3% to 8%. The first metal particles include spherical particles and flake particles, with a mass ratio of flake particles to spherical particles of 5:5. The maximum size range of the flake particles is 1μm to 3μm, and the maximum size range of the spherical particles is 100nm to 400nm. The width of the printed electrode structure is 30μm to 300μm. The curing temperature is 170℃ to 235℃, and the curing time is 15min to 30min.

[0138] The tensile force and contact resistance between the electrode layer and the barrier layer were tested using a tensile testing machine and the TLM method. The thickness of the organic layer 301 between the barrier layer 20 and the electrode layer 302 was measured under TEM, and the thickness of the organic layer ranged from 1 nm to 20 nm. The test results showed that the tensile force between the electrode layer 302 and the barrier layer 20 was 0.5 N / mm to 1 N / mm, and the contact resistivity was 30 mΩ·cm. 2 ~120mΩ·cm 2 .

[0139] For example, in the copper paste, the proportion of first metal particles is 88%, the proportion of organic components is 7%, and the proportion of solvents and other components is 5%. The mass ratio of flake particles to spherical particles in the first metal particles is 5:5. The size range of the flake particles is 1μm to 3μm, the size range of the spherical particles is 100nm to 400nm, the width of the electrode structure is 80μm, the curing temperature is 180℃, and the curing time is 30min. TEM detection shows that an organic layer 301 is formed between the barrier layer 20 and the electrode layer 302. The thickness of the organic layer is between 1nm and 20nm. Within the organic layer, there is a continuous portion with a length of 50nm within a 50nm length range. Within this continuous portion, the length with a thickness of 1nm-5nm is 15nm, and within the continuous portion, the length with a thickness of 5nm-20nm is 35nm. Testing shows that the tensile force between the electrode layer 302 and the barrier layer 20 is 1N / mm, and the contact resistivity is 60mΩ·cm. 2 .

[0140] Compared to existing technologies, the proportion of the first metal particles in the copper paste is adjusted to 93%. The proportion of organic components in the copper paste is 2%, and the proportion of solvents and other components is 5%. The mass ratio of flake particles to spherical particles in the first metal particles is 3:7. The maximum size range of the flake particles is 1μm to 3μm, and the maximum size range of the spherical particles is 100nm to 400nm. The width of the electrode structure is 80μm. The curing temperature is 250℃, and the curing time is 40min. TEM testing shows that there is no organic layer 301 between the barrier layer 20 and the electrode layer 302 (the thickness of the organic layer 301 is less than 1nm, so it can be considered that there is no organic layer 301 between the barrier layer 20 and the electrode layer 302). The test shows that the tensile force between the electrode layer 302 and the barrier layer 20 is 0.3N / mm, and the contact resistivity is 50mΩ·cm. 2By comparison, it can be seen that, since an organic layer 301 is formed between the electrode layer 302 and the barrier layer 20 in this application, and the length of the bonding portion (the thickness of the organic layer is 5nm-20nm) and the conductive portion, i.e. the length of the conductive contact point (the thickness of the organic layer is 1nm-5nm), are controlled in the organic layer 301, the electrode layer 302 and the barrier layer 20 in this application have a better bonding force, and the contact resistance between the electrode layer 302 and the barrier layer 20 is lower.

[0141] This application also provides a photovoltaic module, including multiple battery strings, each battery string including multiple solar cells and multiple interconnects, the interconnects being used to connect the multiple solar cells in series; wherein, the solar cell is any of the aforementioned solar cells 100 of this application.

[0142] The features and effects described in this application for the solar cell 100 are also applicable to the photovoltaic module of this application, and will not be repeated here.

[0143] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

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