Photovoltaic cell and photovoltaic module

Abstract

The application discloses a photovoltaic cell and a photovoltaic module. The photovoltaic cell comprises a substrate and an electrode. The electrode comprises a first electrode layer and a second electrode layer arranged in a stack. The first electrode layer is arranged on a surface of the substrate. The second electrode layer is arranged on a side of the first electrode layer away from the substrate. At least one of the density, the interfacial tension and the viscosity of the first electrode layer is different from that of the second electrode layer. By arranging the electrode as the first electrode layer and the second electrode layer arranged in a stack, the characteristics of the first electrode layer and the second electrode layer are different. The low contact resistivity, the low grid line resistivity, the good anti-friction grid breaking performance, the stable weather resistance and the weldability of the electrode can be realized. The linear quality of the electrode can be improved. The conversion efficiency of the photovoltaic cell can be improved. The cost can be saved.

Description

Technical Field

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

[0002] Currently, the electrodes in photovoltaic cells use single-layer and uniform grid lines. Such grid lines cannot simultaneously achieve multiple performance characteristics, such as low contact resistivity, low grid line resistivity, good resistance to friction breakage, stable weather resistance, and weldability. Specifically, if the grid lines need to have low contact resistivity, it will affect printability. If the grid lines need to have low grid line resistivity, it will increase the proportion of highly conductive fillers, which will increase the brittleness of the grid lines, resulting in poor resistance to friction breakage and increased costs. If the grid lines need to have good weldability, it is necessary to increase the metal content in the welding area and adjust the type of resin, which will lead to increased costs and increased grid line resistivity. If the grid lines need to have weather resistance, it is necessary to increase the density of the grid lines, increase the proportion of macromolecular resins, or use additives, which will increase contact resistivity and grid line resistivity, as well as increase costs. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a photovoltaic cell that can maintain low contact resistivity of the electrodes, low grid line resistivity, good resistance to friction and grid breakage, stable weather resistance, and weldability.

[0004] The present invention further proposes a photovoltaic module.

[0005] A photovoltaic cell according to a first aspect of the present invention includes: a substrate; and an electrode comprising a first electrode layer and a second electrode layer stacked thereon, the first electrode layer being disposed on the surface of the substrate, and the second electrode layer being disposed on the side of the first electrode layer away from the substrate, wherein at least one of the density, interfacial tension, and viscosity of the first electrode layer is different from that of the second electrode layer; wherein the density of the first electrode layer is ρ1, the density of the second electrode layer is ρ2, and ρ1 and ρ2 satisfy the relationship: ρ1-ρ2≤0.15g / cm³; and / or the interfacial tension of the first electrode layer is γ1, the interfacial tension of the second electrode layer is γ2, and γ1 and γ2 satisfy the relationship: γ1-γ2≤3mN / m; and / or the interfacial tension of the first electrode layer is γ1, the interfacial tension of the second electrode layer is γ2, and γ1 and γ2 satisfy the relationship: 25mN / m≤γ1≤45mN / m, 25mN / m≤γ2≤45mN / m.

[0006] According to the photovoltaic cell of the present invention, by setting the electrodes as a stacked first electrode layer and a second electrode layer, and taking advantage of the different characteristics of the first electrode layer and the second electrode layer, the electrodes can achieve low contact resistivity, low grid line resistivity, good anti-friction grid breakage performance, stable weather resistance and weldability, thereby improving the linear quality of the electrodes, increasing the conversion efficiency of the photovoltaic cell, and saving costs.

[0007] According to some embodiments of the present invention, the density of the first electrode layer is ρ1, the density of the second electrode layer is ρ2, and ρ1 and ρ2 satisfy the relationship: ρ1 > ρ2; and / or the interfacial tension of the first electrode layer is γ1, the interfacial tension of the second electrode layer is γ2, and γ1 and γ2 satisfy the relationship: γ1 > γ2; and / or the viscosity of the first electrode layer is η1, the viscosity of the second electrode layer is η2, and η1 and η2 satisfy the relationship: η1 < η2.

[0008] According to some embodiments of the present invention, the width of the first electrode layer is L1, the width of the second electrode layer is L2, and L1 and L2 satisfy the relationship: L1 > L2; and / or the height of the first electrode layer is h1, the height of the second electrode layer is h2, and h1 and h2 satisfy the relationship: h1 < h2.

[0009] According to some embodiments of the present invention, the width of the first electrode layer is L1, the height of the first electrode layer is h1, and L1 and h1 satisfy the following relationship: 15μm≤L1≤50μm, h1≥3μm.

[0010] According to some embodiments of the present invention, the first electrode layer is one of a silver layer and a silver-clad copper layer, and the second electrode layer is one of a silver layer, a copper layer, and a silver-clad copper layer.

[0011] According to some embodiments of the present invention, the electrode further includes: a third electrode layer disposed on the side of the second electrode layer away from the first electrode layer, wherein the third electrode layer has at least one different from the first electrode layer and the second electrode layer in terms of density, interfacial tension and viscosity.

[0012] According to some embodiments of the present invention, the density of the first electrode layer is ρ1, the density of the second electrode layer is ρ2, and the density of the third electrode layer is ρ3, wherein ρ1, ρ2, and ρ3 satisfy the relationship: ρ1 > ρ2 > ρ3; and / or the interfacial tension of the first electrode layer is γ1, the interfacial tension of the second electrode layer is γ2, and the interfacial tension of the third electrode layer is γ3, wherein γ1, γ2, and γ3 satisfy the relationship: γ1 > γ2 > γ3; and / or the viscosity of the first electrode layer is η1, the viscosity of the second electrode layer is η2, and the viscosity of the third electrode layer is η3, wherein η1, η2, and η3 satisfy the relationship: η1 < η2 < η3 < 400 Pa*s.

[0013] According to some embodiments of the present invention, the density of the first electrode layer is ρ1, the density of the second electrode layer is ρ2, and the density of the third electrode layer is ρ3. ρ1, ρ2, and ρ3 also satisfy the following relationships: ρ1-ρ2≤0.15g / cm³, ρ2-ρ3≤0.15g / cm³; and / or the interfacial tension of the first electrode layer is γ1, the interfacial tension of the second electrode layer is γ2, and the interfacial tension of the third electrode layer is γ3. γ1, γ2, and γ3 also satisfy the following relationships: γ1-γ2≤3mN / m, γ2-γ3≤3mN / m; and / or the interfacial tension of the first electrode layer is γ1, the interfacial tension of the second electrode layer is γ2, and the interfacial tension of the third electrode layer is γ3. γ1, γ2, and γ3 also satisfy the following relationships: 25mN / m≤γ1≤45mN / m, 25mN / m≤γ2≤45mN / m, 25mN / m≤γ3≤45mN / m.

[0014] According to some embodiments of the present invention, the width of the first electrode layer is L1, the width of the second electrode layer is L2, and the width of the third electrode layer is L3, wherein L1, L2, and L3 satisfy the relationship: L1 > L2 > L3; and / or the height of the first electrode layer is h1, the height of the second electrode layer is h2, and the height of the third electrode layer is h3, wherein h1, h2, and h3 satisfy the relationship: h1 < h2 < h3.

[0015] According to some embodiments of the present invention, the width of the first electrode layer is L1, the height of the first electrode layer is h1, and L1 and h1 satisfy the relationship: 15μm≤L1≤50μm, h1≥3μm; and / or the height of the third electrode layer is h3, and h3 satisfies the relationship: h3≥5μm; and / or the height of the first electrode layer is h1, the height of the second electrode layer is h2, and the height of the third electrode layer is h3, and h1, h2, and h3 also satisfy the relationship: 9μm≤h1+h2+h3≤20μm.

[0016] According to some embodiments of the present invention, the metal particle size in the first electrode layer, the second electrode layer and the third electrode layer is d, and d satisfies the relationship: d≤10μm.

[0017] According to some embodiments of the present invention, the third electrode layer is one of a silver layer and a silver-clad copper layer.

[0018] A photovoltaic module according to a second aspect of the present invention includes: the photovoltaic cell described above.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of a photovoltaic cell according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the slurry in the container being sheared to form an electrode.

[0021] Figure label: 100. Photovoltaic cells; 10. Substrate; 20. Electrode; 21. First electrode layer; 22. Second electrode layer; 23. Third electrode layer; 200. Container. Detailed Implementation

[0022] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0023] The following is for reference. Figure 1 and Figure 2 A photovoltaic cell 100 according to an embodiment of the present invention is described.

[0024] like Figure 1 and Figure 2 As shown, a photovoltaic cell 100 according to an embodiment of the present invention includes a substrate 10 and an electrode 20. The electrode 20 includes a first electrode layer 21 and a second electrode layer 22 stacked together. The first electrode layer 21 is disposed on the surface of the substrate 10, and the second electrode layer 22 is disposed on the side of the first electrode layer 21 away from the substrate 10. At least one of the density, interfacial tension and viscosity of the first electrode layer 21 is different from that of the second electrode layer 22.

[0025] It is understandable that the first electrode layer 21 and the second electrode layer 22 are stacked, which allows the electrode 20 to form a multi-layer design. The differences between the different electrode layers can be used to avoid the disadvantages of a single electrode layer. The first electrode layer 21 is disposed on the surface of the substrate 10 and is attached to the substrate 10, so that there is no gap between the first electrode layer 21 and the substrate 10, making the structure of the photovoltaic cell 100 more compact. The second electrode layer 22 is disposed on the first electrode layer 21 and is located on the side of the first electrode layer 21 away from the substrate 10. This allows the second electrode layer 22, the first electrode layer 21 and the substrate 10 to be arranged sequentially. The second electrode layer 22 can undertake the function of current conduction, and the first electrode layer 21 can ensure good electrical contact with the substrate 10, thereby ensuring the current collection performance of the electrode 20.

[0026] Both the first electrode layer 21 and the second electrode layer 22 are formed from a slurry, and the slurries differ in their material physical properties. At least one of the parameters—density, interfacial tension, and viscosity—of the first electrode layer 21 and the second electrode layer 22 differs. This allows for a layered design of the first electrode layer 21 and the second electrode layer 22. The first electrode layer 21 adapts to the wetting, adhesion, and contact characteristics of the substrate 10, while the second electrode layer 22 can form a highly conductive structure. This ensures low contact resistivity, low grid line resistivity, good anti-friction grid breakage performance, stable weather resistance, and weldability of the electrode 20, thereby improving the linear quality of the electrode 20 and the conversion efficiency of the photovoltaic cell 100. For example, the substrate 10 is composed of a silicon layer and a transparent conductive film, with the first electrode layer 21 disposed on the transparent conductive film. This ensures that the current of the photovoltaic cell 100 flows through the transparent conductive film to the electrode 20, and also ensures good electrical contact between the first electrode layer 21 and the transparent conductive film.

[0027] Therefore, by setting the electrode 20 as a stacked first electrode layer 21 and second electrode layer 22, and taking advantage of the different characteristics of the first electrode layer 21 and the second electrode layer 22, the electrode 20 can achieve low contact resistivity, low grid line resistivity, good anti-friction grid breakage performance, stable weather resistance and weldability, thereby improving the linear quality of the electrode 20, increasing the conversion efficiency of the photovoltaic cell 100, and saving costs.

[0028] Optionally, the density of the first electrode layer 21 is ρ1, and the density of the second electrode layer 22 is ρ2, where ρ1 and ρ2 satisfy the relationship: ρ1 > ρ2.

[0029] Specifically, the relationship between the density of the first electrode layer 21 and the density of the second electrode layer 22 must be within a reasonable range. If the density of the first electrode layer 21 is less than or equal to the density of the second electrode layer 22, the second electrode layer 22 will gradually invade the first electrode layer 21. After the first electrode layer 21 and the second electrode layer 22 mix, a single electrode layer will be formed, which will make it impossible to guarantee the low contact resistivity, low grid line resistivity, good anti-friction grid breakage performance, stable weather resistance, and weldability of the electrode 20. If the density of the first electrode layer 21 is greater than the density of the second electrode layer 22, it can prevent the first electrode layer 21 and the second electrode layer 22 from mixing and can also maintain the difference between the first electrode layer 21 and the second electrode layer 22, thereby ensuring the stability of the first electrode layer 21 and the second electrode layer 22, and also ensuring the low contact resistivity, low grid line resistivity, good anti-friction grid breakage performance, stable weather resistance, and weldability of the electrode 20.

[0030] Optionally, the interfacial tension of the first electrode layer 21 is γ1, and the interfacial tension of the second electrode layer 22 is γ2. γ1 and γ2 satisfy the relationship: γ1 > γ2.

[0031] Specifically, the relationship between the interfacial tension of the first electrode layer 21 and the interfacial tension of the second electrode layer 22 must be within a reasonable range. If the interfacial tension of the first electrode layer 21 is less than or equal to the interfacial tension of the second electrode layer 22, the first electrode layer 21 will spread along the width direction, increasing the width of the electrode 20 and the light-shielding area, which is not conducive to light collection and may also penetrate into the edge of the substrate 10, causing a short circuit risk. If the interfacial tension of the first electrode layer 21 is greater than the interfacial tension of the second electrode layer 22, the first electrode layer 21 can wet the transparent conductive film, reduce the contact resistivity between the first electrode layer 21 and the substrate 10, and improve the adhesion of the first electrode layer 21 to the substrate 10. The second electrode layer 22 maintains its own state, reducing light-shielding loss, and also allows the second electrode layer 22 and the first electrode layer 21 to form a good bond, thereby ensuring the optical and electrical performance of the electrode 20.

[0032] Optionally, the viscosity of the first electrode layer 21 is η1, and the viscosity of the second electrode layer 22 is η2, and η1 and η2 satisfy the relationship: η1 < η2.

[0033] Specifically, the relationship between the viscosity of the first electrode layer 21 and the viscosity of the second electrode layer 22 should be within a reasonable range. If the viscosity of the first electrode layer 21 is greater than or equal to the viscosity of the second electrode layer 22, it will lead to a decrease in the flowability and wettability of the first electrode layer 21, increase the contact resistance between the first electrode layer 21 and the transparent conductive film, and also cause the second electrode layer 22 to penetrate the first electrode layer 21, forming a single electrode 20. If the viscosity of the first electrode layer 21 is less than the viscosity of the second electrode layer 22, it can not only improve the flowability and wettability of the slurry, but also enhance the bonding effect between the first electrode layer 21 and the transparent conductive film, reduce the contact resistance between the two, ensure the aspect ratio of the electrode 20, reduce the light-shielding loss of the electrode 20, avoid the mixing and diffusion of the first electrode layer 21 and the second electrode layer 22, and thus ensure the regularity and conductivity of the electrode 20.

[0034] Optionally, the density of the first electrode layer 21 is ρ1, and the density of the second electrode layer 22 is ρ2, where ρ1 and ρ2 satisfy the relationship: ρ1-ρ2≤0.15g / cm³.

[0035] Specifically, the relationship between the density of the first electrode layer 21 and the density of the second electrode layer 22 must be within a reasonable range. If the difference between the density of the first electrode layer 21 and the density of the second electrode layer 22 is greater than 0.15 g / cm³, this will lead to an excessively large density difference between the first electrode layer 21 and the second electrode layer 22, resulting in separation or mixing of the slurry of the first electrode layer 21 and the slurry of the second electrode layer 22 when static, and will also affect the molding stability of the first electrode layer 21 and the second electrode layer 22. If the difference between the density of the first electrode layer 21 and the density of the second electrode layer 22 is less than or equal to 0.15 g / cm³, this can control the density of the first electrode layer 21 and the second electrode layer 22. The density difference between the second electrode layer 22 and the first electrode layer 21 during printing and curing can prevent phenomena such as slurry separation, sedimentation, interface separation, or contour distortion between the two. This ensures the tightness of the bond between the first electrode layer 21 and the second electrode layer 22, the uniformity of the cross-sectional transition between the first electrode layer 21 and the second electrode layer 22, and the structural stability of the first electrode layer 21 and the second electrode layer 22. It also prevents phenomena such as collapse, displacement, or internal defects in the first electrode layer 21 and the second electrode layer 22, thereby reducing the contact resistance of the electrode 20 and ensuring the stability and reliability of the conductive properties of the electrode 20.

[0036] Optionally, the interfacial tension of the first electrode layer 21 is γ1, and the interfacial tension of the second electrode layer 22 is γ2. γ1 and γ2 satisfy the relationship: γ1-γ2≤3mN / m.

[0037] Specifically, the relationship between the interfacial tension of the first electrode layer 21 and the interfacial tension of the second electrode layer 22 must be within a reasonable range. If the difference between the interfacial tension of the first electrode layer 21 and the interfacial tension of the second electrode layer 22 is greater than 3 mN / m, it will lead to phenomena such as edge shrinkage or cross-sectional separation between the first electrode layer 21 and the second electrode layer 22, which cannot guarantee the tightness of the bonding between the first electrode layer 21 and the second electrode layer 22, nor can it guarantee the structural stability of the electrode 20. If the difference between the interfacial tension of the first electrode layer 21 and the interfacial tension of the second electrode layer 22 is less than or equal to 3 mN / m, it can not only maintain the interfacial tension of the first electrode layer 21, but also ensure the structural stability of the electrode 20. The interface compatibility with the second electrode layer 22 can also prevent phenomena such as poor wetting, edge shrinkage, interface separation or mutual repulsion of the first electrode layer 21 and the second electrode layer 22 during the printing process. It can also prevent the spontaneous flow of the paste between the two, which would disrupt the stability of static layering and cause dynamic laminar flow. This ensures the tightness of the bonding between the first electrode layer 21 and the second electrode layer 22, as well as the continuity and uniformity of the interface. It can also prevent diffusion between the first electrode layer 21 and the second electrode layer 22, and avoid problems such as shape distortion, breakage or contour deviation of the electrode 20. In this way, it can improve the overall structural stability and conductivity of the electrode 20.

[0038] Optionally, the interfacial tension of the first electrode layer 21 is γ1, and the interfacial tension of the second electrode layer 22 is γ2. γ1 and γ2 satisfy the following relationship: 25mN / m≤γ1≤45mN / m, 25mN / m≤γ2≤45mN / m.

[0039] Specifically, the interfacial tension of the first electrode layer 21 must be within a reasonable range. If the interfacial tension of the first electrode layer 21 is less than 25 mN / m, it will cause the second electrode layer 22 and the first electrode layer 21 to mix when the first electrode layer 21 is static, forming a single electrode layer. This will result in excessive spreading of the slurry forming the first electrode layer 21, a larger width of the first electrode layer 21, and consequently, a larger light-blocking area. If the interfacial tension of the first electrode layer 21 is greater than 45 mN / m, it will affect the stability of the slurry forming the first electrode layer 21 when it is laid on the substrate 10. It will also lead to poor wetting of the first electrode layer 21, incomplete printing, and high contact resistance. When the interfacial tension of 21 is within a reasonable range, the paste forming the first electrode layer 21 can have wetting properties that match the transparent conductive film, optimize the light-shielding area of ​​the first electrode layer 21, reduce the contact resistance between the first electrode layer 21 and the transparent conductive film, ensure the printability of the paste forming the first electrode layer 21, and ensure the quality and strength of the paste after molding. This can ensure the conductivity stability of the first electrode layer 21, improve the interfacial compatibility between the first electrode layer 21 and the second electrode layer 22, avoid problems such as repulsion or bonding failure between the first electrode layer 21 and the second electrode layer 22, and thus ensure the overall performance consistency and photoelectric conversion efficiency of the electrode 20.

[0040] Similarly, the interfacial tension of the second electrode layer 22 must be within a reasonable range. If the interfacial tension of the second electrode layer 22 is less than 25 mN / m, it will cause the second electrode layer 22 and the first electrode layer 21 to mix when the second electrode layer 22 is static, forming a single electrode layer. This will result in excessive spreading of the slurry forming the second electrode layer 22, a larger width of the second electrode layer 22, and consequently, a larger shading area. If the interfacial tension of the second electrode layer 22 is greater than 45 mN / m, it will affect the stability of the slurry forming the second electrode layer 22 when laid on the substrate 10, and will also lead to poor wetting and incomplete printing of the second electrode layer 22. With high contact resistance, if the interfacial tension of the second electrode layer 22 is within a reasonable range, the light-shielding area of ​​the second electrode layer 22 can be optimized, the contact resistance between the second electrode layer 22 and the first electrode layer 21 can be reduced, the printing compatibility of the paste forming the second electrode layer 22 can be guaranteed, and the quality and strength of the paste after molding can be guaranteed, thereby ensuring the conductivity stability of the second electrode layer 22. It can also improve the interfacial compatibility between the first electrode layer 21 and the second electrode layer 22, avoiding problems such as repulsion or bonding failure between the first electrode layer 21 and the second electrode layer 22, and thus ensuring the overall performance consistency and photoelectric conversion efficiency of the electrode 20.

[0041] Optionally, such as Figure 1 As shown, the width of the first electrode layer 21 is L1, and the width of the second electrode layer 22 is L2. L1 and L2 satisfy the relationship: L1 > L2.

[0042] Specifically, the relationship between the width of the first electrode layer 21 and the width of the second electrode layer 22 should be within a reasonable range. If the width of the first electrode layer 21 is less than or equal to the width of the second electrode layer 22, the first electrode layer 21 will not be able to support the second electrode layer 22, and the second electrode layer 22 will block the first electrode layer 21, resulting in damage to the performance of the first electrode layer 21 and thus affecting the current transmission capability of the electrode 20. If the width of the first electrode layer 21 is greater than or equal to the width of the second electrode layer 22, the contact area between the first electrode layer 21 and the transparent conductive film can be guaranteed, ensuring sufficient bonding between the two and reducing the contact resistance between the first electrode layer 21 and the transparent conductive film. The second electrode layer 22 can reduce the shading area, improve the light utilization rate of the photovoltaic cell 100, and the first electrode layer 21 and the second electrode layer 22 can form a higher aspect ratio, ensuring the current transmission capability, thereby ensuring the contact stability between the electrode 20 and the substrate 10, optimizing the photoelectric conversion efficiency of the photovoltaic cell 100, reducing the loss of the photovoltaic cell 100, and thus improving the power generation efficiency of the photovoltaic cell 100.

[0043] Optionally, such as Figure 1 As shown, the height of the first electrode layer 21 is h1, and the height of the second electrode layer 22 is h2. h1 and h2 satisfy the relationship: h1 < h2.

[0044] Specifically, the relationship between the height of the first electrode layer 21 and the height of the second electrode layer 22 should be within a reasonable range. If the height of the first electrode layer 21 is greater than or equal to the height of the second electrode layer 22, it will result in poor wettability between the first electrode layer 21 and the transparent conductive film, increasing the contact resistance between them and causing slurry waste, which in turn leads to poor conductivity of the photovoltaic cell 100. If the height of the first electrode layer 21 is less than the height of the second electrode layer 22, it can improve the wettability between the first electrode layer 21 and the transparent conductive film, reduce the contact resistance between the first electrode layer 21 and the transparent conductive film, avoid slurry waste, and reduce the resistance between the second electrode layer 22 and the first electrode layer 21 without increasing the light-shielding area of ​​the second electrode layer 22. This can ensure the tightness of the bonding between the first electrode layer 21 and the second electrode layer 22, thereby improving the conductivity of the electrode 20 and the photoelectric conversion efficiency of the photovoltaic cell 100.

[0045] Optionally, such as Figure 1 As shown, the width of the first electrode layer 21 is L1, and the height of the first electrode layer 21 is h1. L1 and h1 satisfy the following relationship: 15μm≤L1≤50μm, h1≥3μm.

[0046] Specifically, the width of the first electrode layer 21 must be within a reasonable range. If the width of the first electrode layer 21 is less than 15 μm, the contact area between the first electrode layer 21 and the transparent conductive film will be too small, reducing the adhesion reliability of the first electrode layer 21 and causing problems such as false printing or poor contact. If the width of the first electrode layer 21 is greater than 50 μm, the paste used to form the first electrode layer 21 will be wasted, and the light-shielding area of ​​the first electrode layer 21 will be too large, affecting the photoelectric conversion efficiency of the photovoltaic cell 100. If the width of the first electrode layer 21 is within a reasonable range, it can ensure that there is sufficient contact area between the first electrode layer 21 and the transparent conductive film, improve the adhesion reliability of the first electrode layer 21 on the transparent conductive film, prevent the first electrode layer 21 from having false printing and poor contact, and ensure the light-shielding area of ​​the first electrode layer 21, thereby ensuring the photoelectric conversion efficiency of the photovoltaic cell 100.

[0047] The height of the first electrode layer 21 must be within a reasonable range. If the height of the first electrode layer 21 is less than 3 μm, its conductivity will be insufficient, increasing current transmission loss. It will also result in insufficient wetting between the first electrode layer 21 and the transparent conductive film, failing to provide stable support for the second electrode layer 22. If the height of the first electrode layer 21 is greater than or equal to 3 μm, its conductivity can be guaranteed, current transmission loss reduced, wetting between the first electrode layer 21 and the transparent conductive film ensured, and stable support for the second electrode layer 22 provided, thus guaranteeing the conductivity and conductivity stability of the electrode 20. For example, if the sum of the heights of the first electrode layer 21 and the second electrode layer 22 is 8-20 μm, the electrode 20 can be printed in a single pass, reducing paste consumption and saving material and labor costs.

[0048] Specifically, the first electrode layer 21 is one of a silver layer and a silver-clad copper layer, and the second electrode layer 22 is one of a silver layer, a copper layer, and a silver-clad copper layer.

[0049] In other words, if the first electrode layer 21 is a silver layer, silver has excellent conductivity, chemical stability and good wettability in contact with the transparent conductive film. This can reduce the contact resistance between the first electrode layer 21 and the transparent conductive film, improve the interfacial adhesion of the first electrode layer 21, and prevent metal diffusion from damaging the battery cell. If the first electrode layer 21 is a silver-coated copper layer, the amount of silver used can be reduced while ensuring contact performance, thereby optimizing the cost of the electrode 20.

[0050] If the second electrode layer 22 is a silver layer, the silver layer has strong conductivity and long-term reliability. If the second electrode layer 22 is a copper layer, the material cost of the second electrode layer 22 can be reduced. If the second electrode layer 22 is a silver-clad copper layer, it can not only meet the requirements of conductivity, oxidation resistance and performance, but also ensure the strength of the second electrode layer 22, thereby achieving a balance between power generation efficiency and cost.

[0051] In addition, such as Figure 1 and Figure 2 As shown, electrode 20 further includes a third electrode layer 23, which is disposed on the side of the second electrode layer 22 away from the first electrode layer 21. The third electrode layer 23 has at least one different density, interfacial tension and viscosity from the first electrode layer 21 and the second electrode layer 22.

[0052] It is understandable that the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 are stacked, which allows the electrode 20 to form a multi-layer design. The differences between the different electrode layers 20 can be used to avoid the shortcomings of a single electrode 20. The third electrode layer 23 is disposed on the second electrode layer 22, and the third electrode layer 23 is located on the side of the second electrode layer 22 away from the first electrode layer 21. In this way, the third electrode layer 23, the second electrode layer 22, and the first electrode layer 21 can be arranged sequentially. The third electrode layer 23 and the second electrode layer 22 can undertake the function of current conduction, and the first electrode layer 21 can ensure good electrical contact with the substrate 10, thereby ensuring the current collection performance of the electrode 20.

[0053] The third electrode layer 23 is also formed from slurry. The slurry of the third electrode layer 23 and the first electrode layer 21 are different in material physical properties. The slurry of the third electrode layer 23 and the second electrode layer 22 are also different in material physical properties. At least one of the density, interfacial tension and viscosity of the third electrode layer 23 is different from that of the first electrode layer 21 and the second electrode layer 22. This allows for a layered design of the first electrode layer 21, the second electrode layer 22 and the third electrode layer 23, thereby ensuring that the electrode 20 has low contact resistivity, low grid line resistivity, good anti-friction grid breakage performance, stable weather resistance and weldability. This can further improve the linear quality of the electrode 20 and the conversion efficiency of the photovoltaic cell 100.

[0054] Optionally, the density of the first electrode layer 21 is ρ1, the density of the second electrode layer 22 is ρ2, and the density of the third electrode layer 23 is ρ3. ρ1, ρ2, and ρ3 satisfy the relationship: ρ1 > ρ2 > ρ3.

[0055] Optionally, the relationship between the densities of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 should be within a reasonable range. If the density of the first electrode layer 21 is less than or equal to the density of the second electrode layer 22, and the density of the second electrode layer 22 is less than or equal to the density of the third electrode layer 23, the second electrode layer 22 will gradually encroach on the first electrode layer 21, and the third electrode layer 23 will gradually encroach on the second electrode layer 22. The first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 will then mix to form a single electrode layer, which will compromise the low contact resistivity, low grid line resistivity, good anti-friction grid breakage performance, stable weather resistance, and other properties of the electrode 20. For weldability, if the density of the first electrode layer 21 is greater than the density of the second electrode layer 22, and the density of the second electrode layer 22 is greater than the density of the third electrode layer 23, this can prevent the first electrode layer 21 and the second electrode layer 22 from mixing, as well as the third electrode layer 23 and the second electrode layer 22 from mixing. It can also maintain the differences between the first electrode layer 21 and the second electrode layer 22, as well as the differences between the second electrode layer 22 and the third electrode layer 23. This can ensure the stability of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23, and also ensure the low contact resistivity, low grid line resistivity, good anti-friction grid breakage performance, stable weather resistance, and weldability of the electrode 20.

[0056] Optionally, the interfacial tension of the first electrode layer 21 is γ1, the interfacial tension of the second electrode layer 22 is γ2, and the interfacial tension of the third electrode layer 23 is γ3. γ1, γ2, and γ3 satisfy the relationship: γ1 > γ2 > γ3.

[0057] Specifically, the relationship between the interfacial tension of the first electrode layer 21, the interfacial tension of the second electrode layer 22, and the interfacial tension of the third electrode layer 23 must be within a reasonable range. If the interfacial tension of the first electrode layer 21 is less than or equal to the interfacial tension of the second electrode layer 22, and the interfacial tension of the second electrode layer 22 is less than or equal to the interfacial tension of the third electrode layer 23, this will cause the first electrode layer 21 to spread along the width direction, increasing the width of the electrode 20 and the light-blocking area, which is not conducive to light collection and may also penetrate into the edge of the substrate 10, causing a short circuit risk. If the interfacial tension of the first electrode layer 21 is greater than... The interfacial tension of the second electrode layer 22 is greater than that of the third electrode layer 23. This allows the first electrode layer 21 to wet the transparent conductive film, reducing the contact resistivity between the first electrode layer 21 and the substrate 10, and improving the adhesion of the first electrode layer 21 to the substrate 10. The second electrode layer 22 and the third electrode layer 23 maintain their own state, reducing light shading loss. It also allows the second electrode layer 22 and the first electrode layer 21 to form a good bond, as well as the third electrode layer 23 and the second electrode layer 22 to form a good bond, thereby ensuring the optical and electrical performance of the electrode 20.

[0058] Optionally, the viscosity of the first electrode layer 21 is η1, the viscosity of the second electrode layer 22 is η2, and the viscosity of the third electrode layer 23 is η3. η1, η2, and η3 satisfy the relationship: η1 < η2 < η3 < 400 Pa*s.

[0059] Specifically, the viscosity of the first electrode layer 21, the viscosity of the second electrode layer 22, and the viscosity of the third electrode layer 23 must be within a reasonable range. If the viscosity of the first electrode layer 21 is greater than or equal to the viscosity of the second electrode layer 22, and the viscosity of the second electrode layer 22 is greater than or equal to the viscosity of the third electrode layer 23, this will lead to a decrease in the layup fluidity and wettability of the first electrode layer 21, increasing the contact resistance between the first electrode layer 21 and the transparent conductive film. It will also cause the second electrode layer 22 to penetrate the first electrode layer 21, and the third electrode layer 23 to penetrate the second electrode layer 22, forming a single electrode 20. If the viscosity of the first electrode layer 21 is greater than or equal to the viscosity of the second electrode layer 22, and the viscosity of the third electrode layer 23 is greater than or equal to the viscosity of the third electrode layer 23, this will lead to a decrease in the layup fluidity and wettability of the first electrode layer 21, increasing the contact resistance between the first electrode layer 21 and the transparent conductive film. Furthermore, it will cause the second electrode layer 22 to penetrate the first electrode layer 21, and the third electrode layer 23 to penetrate the second electrode layer 22, forming a single electrode 20. The viscosity of the first electrode layer 21 is less than that of the second electrode layer 22, the viscosity of the second electrode layer 22 is less than that of the third electrode layer 23, and the viscosity of the third electrode layer 23 is less than 400 Pa*s. This not only improves the fluidity and wetting and spreading properties of the slurry, but also enhances the bonding effect between the first electrode layer 21 and the transparent conductive film, reduces the contact resistance between them, ensures the aspect ratio of the electrode 20, reduces the light-shielding loss of the electrode 20, avoids the mixing and flow of the first electrode layer 21 and the second electrode layer 22, and avoids the mixing and flow of the second electrode layer 22 and the third electrode layer 23, thereby ensuring the regularity and conductivity of the electrode 20.

[0060] Optionally, the density of the first electrode layer 21 is ρ1, the density of the second electrode layer 22 is ρ2, and the density of the third electrode layer 23 is ρ3. ρ1, ρ2, and ρ3 also satisfy the following relationship: ρ1-ρ2≤0.15g / cm³, ρ2-ρ3≤0.15g / cm³.

[0061] Specifically, the relationship between the density of the first electrode layer 21 and the density of the second electrode layer 22 must be within a reasonable range. If the difference between the density of the first electrode layer 21 and the density of the second electrode layer 22 is greater than 0.15 g / cm³, this will lead to an excessively large density difference between the first electrode layer 21 and the second electrode layer 22, resulting in separation or mixing of the slurry of the first electrode layer 21 and the slurry of the second electrode layer 22 when static, and will also affect the molding stability of the first electrode layer 21 and the second electrode layer 22. If the difference between the density of the first electrode layer 21 and the density of the second electrode layer 22 is less than or equal to 0.15 g / cm³, this can control the density of the first electrode layer 21 and the second electrode layer 22. The density difference between the second electrode layer 22 and the first electrode layer 21 during printing and curing can prevent phenomena such as slurry separation, sedimentation, interface separation, or contour distortion between the two. This ensures the tightness of the bond between the first electrode layer 21 and the second electrode layer 22, the uniformity of the cross-sectional transition between the first electrode layer 21 and the second electrode layer 22, and the structural stability of the first electrode layer 21 and the second electrode layer 22. It also prevents phenomena such as collapse, displacement, or internal defects in the first electrode layer 21 and the second electrode layer 22, thereby reducing the contact resistance of the electrode 20 and ensuring the stability and reliability of the conductive properties of the electrode 20.

[0062] The density relationship between the second electrode layer 22 and the third electrode layer 23 should be within a reasonable range. If the difference between the densities of the second electrode layer 22 and the third electrode layer 23 is greater than 0.15 g / cm³, it will lead to an excessive density difference between the two electrode layers, causing the slurries of the second electrode layer 22 and the third electrode layer 23 to separate or mix when static, and will also affect the molding stability of the second electrode layer 22 and the third electrode layer 23. If the difference between the densities of the second electrode layer 22 and the third electrode layer 23 is less than or equal to 0.15 g / cm³, the density of the second electrode layer 22 and the third electrode layer 23 can be controlled. The density difference between electrode layers 23 can prevent phenomena such as slurry separation, sedimentation, interface separation, or contour distortion between the two during the printing and curing of the second electrode layer 22 and the third electrode layer 23. This density difference can ensure the tightness of the bond between the second electrode layer 22 and the third electrode layer 23, the uniformity of the cross-sectional transition between the second electrode layer 22 and the third electrode layer 23, and the structural stability of the second electrode layer 22 and the third electrode layer 23. It can also prevent phenomena such as collapse, displacement, or internal defects in the second electrode layer 22 and the third electrode layer 23, thereby reducing the contact resistance of the electrode 20 and ensuring the stability and reliability of the wire performance of the electrode 20.

[0063] Optionally, the interfacial tension of the first electrode layer 21 is γ1, the interfacial tension of the second electrode layer 22 is γ2, and the interfacial tension of the third electrode layer 23 is γ3. γ1, γ2, and γ3 also satisfy the following relationship: γ1-γ2≤3mN / m, γ2-γ3≤3mN / m.

[0064] Specifically, the relationship between the interfacial tension of the first electrode layer 21 and the interfacial tension of the second electrode layer 22 must be within a reasonable range. If the difference between the interfacial tension of the first electrode layer 21 and the interfacial tension of the second electrode layer 22 is greater than 3 mN / m, it will lead to phenomena such as edge shrinkage or cross-sectional separation between the first electrode layer 21 and the second electrode layer 22, which cannot guarantee the tightness of the bonding between the first electrode layer 21 and the second electrode layer 22, nor can it guarantee the structural stability of the electrode 20. If the difference between the interfacial tension of the first electrode layer 21 and the interfacial tension of the second electrode layer 22 is less than or equal to 3 mN / m, it can not only maintain the interfacial tension of the first electrode layer 21, but also ensure the structural stability of the electrode 20. The interface compatibility with the second electrode layer 22 can also prevent phenomena such as poor wetting, edge shrinkage, interface separation or mutual repulsion of the first electrode layer 21 and the second electrode layer 22 during the printing process. It can also prevent the spontaneous flow of the paste between the two, which would disrupt the stability of static layering and cause dynamic laminar flow. This ensures the tightness of the bonding between the first electrode layer 21 and the second electrode layer 22, as well as the continuity and uniformity of the interface. It can also prevent diffusion between the first electrode layer 21 and the second electrode layer 22, and avoid problems such as shape distortion, breakage or contour deviation of the electrode 20. In this way, it can improve the overall structural stability and conductivity of the electrode 20.

[0065] The relationship between the interfacial tension of the second electrode layer 22 and the interfacial tension of the third electrode layer 23 must be within a reasonable range. If the difference between the interfacial tension of the second electrode layer 22 and the interfacial tension of the third electrode layer 23 is greater than 3 mN / m, it will lead to phenomena such as edge contraction or cross-sectional separation between the second electrode layer 22 and the third electrode layer 23, which will not be able to guarantee the tightness of the bonding between the second electrode layer 22 and the third electrode layer 23, nor will it guarantee the structural stability of the electrode 20. If the difference between the interfacial tension of the second electrode layer 22 and the interfacial tension of the third electrode layer 23 is less than or equal to 3 mN / m, it will not only maintain the tightness of the bonding between the second electrode layer 22 and the third electrode layer 23, but also ensure the structural stability of the electrode 20. The similar interface compatibility of the three electrode layers 23 can also avoid phenomena such as poor wetting, edge shrinkage, interface separation or mutual repulsion between the second electrode layer 22 and the third electrode layer 23 during the printing process. It can also prevent the spontaneous flow of the paste between the two layers, which would disrupt the stability of static layering and cause dynamic laminar flow. This ensures the tightness of the bonding between the second electrode layer 22 and the third electrode layer 23, as well as the continuity and uniformity of the interface. It can also prevent diffusion between the second electrode layer 22 and the third electrode layer 23, and avoid problems such as shape distortion, breakage or contour deviation of the electrode 20. In this way, it can improve the overall structural stability and conductivity of the electrode 20.

[0066] Optionally, the interfacial tension of the first electrode layer 21 is γ1, the interfacial tension of the second electrode layer 22 is γ2, and the interfacial tension of the third electrode layer 23 is γ3. γ1, γ2, and γ3 also satisfy the following relationships: 25mN / m≤γ1≤45mN / m, 25mN / m≤γ2≤45mN / m, and 25mN / m≤γ3≤45mN / m.

[0067] Specifically, the interfacial tension of the first electrode layer 21 must be within a reasonable range. If the interfacial tension of the first electrode layer 21 is less than 25 mN / m, it will cause the second electrode layer 22 and the first electrode layer 21 to mix when the first electrode layer 21 is static, forming a single-layer electrode 20. This will result in excessive spreading of the slurry forming the first electrode layer 21, a larger width of the first electrode layer 21, and consequently, a larger light-blocking area. If the interfacial tension of the first electrode layer 21 is greater than 45 mN / m, it will affect the stability of the slurry forming the first electrode layer 21 when it is laid on the substrate 10. It will also lead to poor wetting of the first electrode layer 21, incomplete printing, and high contact resistance. The interfacial tension of layer 21 is within a reasonable range, which enables the paste forming the first electrode layer 21 to have wetting properties that match the transparent conductive film, optimizes the light-shielding area of ​​the first electrode layer 21, reduces the contact resistance between the first electrode layer 21 and the transparent conductive film, ensures the printability of the paste forming the first electrode layer 21, and guarantees the quality and strength of the paste after molding. This ensures the conductivity stability of the first electrode layer 21, improves the interfacial compatibility between the first electrode layer 21 and the second electrode layer 22, avoids problems such as repulsion or bonding failure between the first electrode layer 21 and the second electrode layer 22, and thus ensures the overall performance consistency and photoelectric conversion efficiency of the electrode 20.

[0068] Similarly, the interfacial tension of the second electrode layer 22 must be within a reasonable range. If the interfacial tension of the second electrode layer 22 is less than 25 mN / m, it will cause the second electrode layer 22 and the first electrode layer 21 to mix when the second electrode layer 22 is static, forming a single layer of electrode 20. This will result in the slurry forming the second electrode layer 22 being over-spread, and the width of the second electrode layer 22 being larger, thus increasing the light-blocking area. If the interfacial tension of the second electrode layer 22 is greater than 45 mN / m, it will affect the stability of the slurry forming the second electrode layer 22 when it is laid on the substrate 10, and will also lead to poor wetting and incomplete printing of the second electrode layer 22. In addition to high contact resistance, if the interfacial tension of the second electrode layer 22 is within a reasonable range, the light-shielding area of ​​the second electrode layer 22 can be optimized, the contact resistance between the second electrode layer 22 and the first electrode layer 21 can be reduced, the printing compatibility of the paste forming the second electrode layer 22 can be guaranteed, the quality and strength of the paste after molding can be guaranteed, thereby ensuring the conductivity stability of the second electrode layer 22, and also improving the interfacial compatibility between the first electrode layer 21 and the second electrode layer 22, avoiding problems such as repulsion or bonding failure between the first electrode layer 21 and the second electrode layer 22, and thus ensuring the overall performance consistency and photoelectric conversion efficiency of the electrode 20.

[0069] The interfacial tension of the third electrode layer 23 must be within a reasonable range. If the interfacial tension of the third electrode layer 23 is less than 25 mN / m, it will cause the third electrode layer 23 and the second electrode layer 22 to mix when the third electrode layer 23 is static, forming a single electrode layer. This will result in excessive spreading of the slurry forming the third electrode layer 23, a larger width of the third electrode layer 23, and consequently, a larger shading area. If the interfacial tension of the third electrode layer 23 is greater than 45 mN / m, it will affect the stability of the slurry forming the third electrode layer 23 when laid on the substrate 10, and will also lead to poor wetting, incomplete printing, and poor adhesion of the third electrode layer 23. High contact resistance, if the interfacial tension of the third electrode layer 23 is within a reasonable range, can optimize the light-shielding area of ​​the third electrode layer 23, reduce the contact resistance between the third electrode layer 23 and the second electrode layer 22, ensure the printing compatibility of the paste forming the third electrode layer 23, ensure the quality and strength of the paste after molding, thereby ensuring the conductivity stability of the third electrode layer 23, and also improve the interfacial compatibility between the third electrode layer 23 and the second electrode layer 22, avoiding problems such as repulsion or bonding failure between the third electrode layer 23 and the second electrode layer 22, and thus ensuring the overall performance consistency and photoelectric conversion efficiency of the electrode 20.

[0070] Optionally, such as Figure 1 As shown, the width of the first electrode layer 21 is L1, the width of the second electrode layer 22 is L2, and the width of the third electrode layer 23 is L3. L1, L2, and L3 satisfy the relationship: L1 > L2 > L3.

[0071] Specifically, the relationship between the widths of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 must be within a reasonable range. If the width of the first electrode layer 21 is less than or equal to the width of the second electrode layer 22, and the width of the second electrode layer 22 is less than or equal to the width of the third electrode layer 23, this will result in the first electrode layer 21 being unable to support the second electrode layer 22, the second electrode layer 22 being unable to support the third electrode layer 23, the second electrode layer 22 blocking the first electrode layer 21, and the third electrode layer 23 blocking the second electrode layer 22, thus impairing the performance of the first electrode layer 21 and the second electrode layer 22, and consequently affecting the current transmission capability of the electrode 20. If the width of the first electrode layer 21 is greater than or equal to the width of the second electrode layer 22, the second electrode layer 21 will be less than or equal to the width of the third electrode layer 23. The width of electrode layer 22 is greater than or equal to the width of third electrode layer 23. This ensures the contact area between first electrode layer 21 and transparent conductive film, guaranteeing sufficient bonding between them and reducing the contact resistance between them. Second electrode layer 22 and third electrode layer 23 reduce the shading area, improving the light utilization rate of photovoltaic cell 100. Furthermore, first electrode layer 21, second electrode layer 22, and third electrode layer 23 can form a higher aspect ratio, ensuring current transmission capability and thus guaranteeing the contact stability between electrode 20 and substrate 10. This also optimizes the photoelectric conversion efficiency of photovoltaic cell 100, reduces photovoltaic cell 100 losses, and ultimately improves the power generation efficiency of photovoltaic cell 100.

[0072] Optionally, such as Figure 1 As shown, the height of the first electrode layer 21 is h1, the height of the second electrode layer 22 is h2, and the height of the third electrode layer 23 is h3. h1, h2, and h3 satisfy the relationship: h1 < h2 < h3.

[0073] Specifically, the relationship between the heights of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 must be within a reasonable range. If the height of the first electrode layer 21 is greater than or equal to the height of the second electrode layer 22, and the height of the second electrode layer 22 is greater than or equal to the height of the third electrode layer 23, this will result in poor wetting between the first electrode layer 21 and the transparent conductive film, increasing the contact resistance between them, and also causing paste waste, thus leading to poor conductivity of the photovoltaic cell 100. If the height of the first electrode layer 21 is less than the height of the second electrode layer 22, and the height of the second electrode layer 22 is less than the height of the third electrode layer 23, then... This can improve the wetting performance between the first electrode layer 21 and the transparent conductive film, reduce the contact resistance between the first electrode layer 21 and the transparent conductive film, avoid waste of slurry, and reduce the resistance between the second electrode layer 22 and the first electrode layer 21, as well as the resistance between the third electrode layer 23 and the second electrode layer 22, without increasing the light-shielding area of ​​the second electrode layer 22 and the third electrode layer 23. This can ensure the tightness of the bonding between the first electrode layer 21 and the second electrode layer 22, as well as the tightness of the bonding between the second electrode layer 22 and the third electrode layer 23, thereby improving the conductivity of the electrode 20 and the photoelectric conversion efficiency of the photovoltaic cell 100.

[0074] Optionally, such as Figure 1 As shown, the height of the third electrode layer 23 is h3, and h3 satisfies the relationship: h3≥5μm.

[0075] Specifically, the height of the third electrode layer 23 should be within a reasonable range. If the height of the third electrode layer 23 is less than 5 μm, it will result in insufficient conductivity of the third electrode layer 23 and increase current transmission loss. If the height of the third electrode layer 23 is greater than or equal to 5 μm, it can ensure the conductivity of the third electrode layer 23 and reduce current transmission loss, thereby ensuring the conductivity and conductivity stability of the electrode 20.

[0076] Optionally, such as Figure 1 As shown, the height of the first electrode layer 21 is h1, the height of the second electrode layer 22 is h2, and the height of the third electrode layer 23 is h3. h1, h2, and h3 also satisfy the relationship: 9μm≤h1+h2+h3≤20μm.

[0077] Specifically, the relationship between the heights of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 must be within a reasonable range. If the sum of the heights of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 is less than 9 μm, this will result in insufficient conductivity of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23, leading to low photodisplay utilization and low structural strength. If the sum of the heights of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 is greater than 20 μm, this will increase the resistance of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23, increase the light-shielding area of ​​the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23, resulting in energy consumption. To reduce losses, if the relationship between the heights of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 is within a reasonable range, the aspect ratio of the electrode 20 can be greater than or equal to 60%, or even reach 70%. This can reduce the phenomenon of frictional breakage of the electrode 20, reduce the resistance between the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 to ensure the current transmission capacity of the electrode 20, and reduce the light-shielding area of ​​the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23, thus ensuring the structural strength of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23. This can make the electrode 20 form stable, avoid local collapse, breakage, and distortion, and thus ensure the photoelectric conversion efficiency of the photovoltaic cell 100.

[0078] Optionally, the metal particle size in the first electrode layer 21, the second electrode layer 22 and the third electrode layer 23 is d, and d satisfies the relationship: d≤10μm.

[0079] Specifically, the metal particle size in the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 must be within a reasonable range. If the metal particle size in the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 is greater than 10 μm, it will cause problems such as incomplete printing, breakage, and rough lines during printing of the paste. It will also increase the resistance of the electrode 20, resulting in uneven contact between the transparent conductive film, the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23. If the metal particle size in the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 is too large, it will cause problems such as incomplete printing, breakage, and rough lines during printing of the paste. It will also increase the resistance of the electrode 20, resulting in uneven contact between the transparent conductive film, the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23. A thickness of less than or equal to 10 μm ensures uniformity of the paste used to form the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23, resulting in smooth printing. This also ensures dense compaction within the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23, thereby reducing the resistance of the electrode 20, improving its conductivity, and reducing unevenness in the contact between the transparent conductive film, the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23. Consequently, the structure of the electrode 20 becomes more regular, improving the photoelectric conversion efficiency of the photovoltaic cell 100.

[0080] Specifically, the third electrode layer 23 is either a silver layer or a silver-clad copper layer. If the third electrode layer 23 is a silver layer, silver has excellent conductivity and chemical stability, which can reduce the contact resistance between the third electrode layer 23 and the second electrode layer 22, improve the interfacial adhesion of the third electrode layer 23, and prevent metal diffusion from damaging the battery cell. If the third electrode layer 23 is a silver-clad copper layer, the amount of silver used can be reduced while ensuring contact performance, thereby optimizing the cost of electrode 20.

[0081] Specifically, such as Figure 2 As shown, the slurry forming the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 is placed sequentially in the container 200. When the slurry is subjected to shearing, it flows out of the container 200 through laminar flow. Moreover, during shearing, the flow velocity and stress of each layer remain consistent, which can avoid turbulent mixing. Based on the cross-sectional shape of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23, the shape of the container 200 opening is designed to be circular, rectangular, triangular, trapezoidal, etc. Finally, the thermodynamic potential energy is controlled by the density, interfacial tension, and miscibility of the slurry, so that the layered state of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 is in the lowest energy state, preventing the diffusion and mutual penetration of adjacent electrode layers 20, thereby enabling the electrodes 20 to form an integrally formed multifunctional layered grid. For example, the Reynolds number of the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23, i.e. the turbulence critical point, is less than 2300. If the turbulence critical point exceeds 2300, turbulence will excite interface fluctuations, causing the first electrode layer 21, the second electrode layer 22, and the third electrode layer 23 to mix. Therefore, it is necessary to control the rate and stress of slurry shearing within a certain range to avoid turbulence.

[0082] A photovoltaic module according to an embodiment of the present invention includes: a photovoltaic cell 100 as described above. By setting the electrode 20 as a stacked first electrode layer 21 and a second electrode layer 22, and utilizing the different characteristics of the first electrode layer 21 and the second electrode layer 22, the electrode 20 can achieve low contact resistivity, low grid line resistivity, good anti-friction grid breakage performance, stable weather resistance and weldability, thereby improving the linear quality of the electrode 20 and the conversion efficiency of the photovoltaic cell 100.

[0083] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0084] In the description of this invention, "first feature" and "second feature" may include one or more of the features. In the description of this invention, "a plurality of" means two or more. In the description of this invention, "above" or "below" the second feature may include direct contact between the first and second features, or it may include contact between the first and second features not being in direct contact but through another feature between them. In the description of this invention, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicating that the first feature is at a higher horizontal level than the second feature.

[0085] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0086] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A photovoltaic cell, characterized in that, include: Base (10); Electrode (20), the electrode (20) includes a first electrode layer (21) and a second electrode layer (22) stacked together, the first electrode layer (21) is disposed on the surface of the substrate (10), and the second electrode layer (22) is disposed on the side of the first electrode layer (21) away from the substrate (10), and at least one of the density, interfacial tension and viscosity of the first electrode layer (21) is different from that of the second electrode layer (22). The interfacial tension of the first electrode layer (21) is γ1, and the interfacial tension of the second electrode layer (22) is γ2. γ1 and γ2 satisfy the relationship: γ1-γ2≤3mN / m. The interfacial tension of the first electrode layer (21) is γ1, and the interfacial tension of the second electrode layer (22) is γ2. γ1 and γ2 satisfy the following relationship: 25mN / m≤γ1≤45mN / m, 25mN / m≤γ2≤45mN / m.

2. The photovoltaic cell according to claim 1, characterized in that, The density of the first electrode layer (21) is ρ1, and the density of the second electrode layer (22) is ρ2. ρ1 and ρ2 satisfy the relationship: ρ1 > ρ2; and / or The density of the first electrode layer (21) is ρ1, and the density of the second electrode layer (22) is ρ2. ρ1 and ρ2 satisfy the relationship: ρ1-ρ2≤0.15g / cm³; and / or The interfacial tension of the first electrode layer (21) is γ1, and the interfacial tension of the second electrode layer (22) is γ2. γ1 and γ2 satisfy the relationship: γ1 > γ2; and / or The viscosity of the first electrode layer (21) is η1, and the viscosity of the second electrode layer (22) is η2. η1 and η2 satisfy the relationship: η1 < η2.

3. The photovoltaic cell according to claim 1, characterized in that, The width of the first electrode layer (21) is L1, and the width of the second electrode layer (22) is L2. L1 and L2 satisfy the relationship: L1 > L2; and / or The height of the first electrode layer (21) is h1, and the height of the second electrode layer (22) is h2. h1 and h2 satisfy the relationship: h1 < h2.

4. The photovoltaic cell according to claim 1, characterized in that, The width of the first electrode layer (21) is L1, and the height of the first electrode layer (21) is h1. L1 and h1 satisfy the following relationship: 15μm≤L1≤50μm, h1≥3μm.

5. The photovoltaic cell according to claim 1, characterized in that, The first electrode layer (21) is one of a silver layer and a silver-clad copper layer, and the second electrode layer (22) is one of a silver layer, a copper layer and a silver-clad copper layer.

6. The photovoltaic cell according to claim 1, characterized in that, The electrode (20) further includes: The third electrode layer (23) is disposed on the side of the second electrode layer (22) away from the first electrode layer (21), and the third electrode layer (23) has at least one different from the first electrode layer (21) and the second electrode layer (22) in terms of density, interfacial tension and viscosity.

7. The photovoltaic cell according to claim 6, characterized in that, The density of the first electrode layer (21) is ρ1, the density of the second electrode layer (22) is ρ2, and the density of the third electrode layer (23) is ρ3. ρ1, ρ2, and ρ3 satisfy the relationship: ρ1 > ρ2 > ρ3; and / or The interfacial tension of the first electrode layer (21) is γ1, the interfacial tension of the second electrode layer (22) is γ2, and the interfacial tension of the third electrode layer (23) is γ3. γ1, γ2, and γ3 satisfy the relationship: γ1 > γ2 > γ3; and / or The viscosity of the first electrode layer (21) is η1, the viscosity of the second electrode layer (22) is η2, and the viscosity of the third electrode layer (23) is η3. η1, η2 and η3 satisfy the relationship: η1 < η2 < η3 < 400 Pa*s.

8. The photovoltaic cell according to claim 6, characterized in that, The density of the first electrode layer (21) is ρ1, the density of the second electrode layer (22) is ρ2, and the density of the third electrode layer (23) is ρ3. ρ1, ρ2, and ρ3 also satisfy the following relationships: ρ1-ρ2≤0.15g / cm³, ρ2-ρ3≤0.15g / cm³; and / or The interfacial tension of the first electrode layer (21) is γ1, the interfacial tension of the second electrode layer (22) is γ2, and the interfacial tension of the third electrode layer (23) is γ3. γ1, γ2, and γ3 also satisfy the following relationships: γ1-γ2≤3mN / m, γ2-γ3≤3mN / m; and / or The interfacial tension of the first electrode layer (21) is γ1, the interfacial tension of the second electrode layer (22) is γ2, and the interfacial tension of the third electrode layer (23) is γ3. γ1, γ2 and γ3 also satisfy the following relationship: 25mN / m≤γ1≤45mN / m, 25mN / m≤γ2≤45mN / m, 25mN / m≤γ3≤45mN / m.

9. The photovoltaic cell according to claim 6, characterized in that, The width of the first electrode layer (21) is L1, the width of the second electrode layer (22) is L2, and the width of the third electrode layer (23) is L3. L1, L2, and L3 satisfy the relationship: L1 > L2 > L3; and / or The height of the first electrode layer (21) is h1, the height of the second electrode layer (22) is h2, and the height of the third electrode layer (23) is h3. h1, h2 and h3 satisfy the relationship: h1 < h2 < h3.

10. The photovoltaic cell according to claim 6, characterized in that, The width of the first electrode layer (21) is L1, and the height of the first electrode layer (21) is h1. L1 and h1 satisfy the following relationship: 15μm≤L1≤50μm, h1≥3μm; and / or The height of the third electrode layer (23) is h3, and h3 satisfies the following relationship: h3≥5μm; and / or The height of the first electrode layer (21) is h1, the height of the second electrode layer (22) is h2, and the height of the third electrode layer (23) is h3. h1, h2 and h3 also satisfy the relationship: 9μm≤h1+h2+h3≤20μm.

11. The photovoltaic cell according to claim 6, characterized in that, The metal particle size in the first electrode layer (21), the second electrode layer (22) and the third electrode layer (23) is d, and d satisfies the relationship: d≤10μm.

12. The photovoltaic cell according to claim 6, characterized in that, The third electrode layer (23) is either a silver layer or a silver-clad copper layer.

13. A photovoltaic module, characterized in that, include: The photovoltaic cell (100) according to any one of claims 1-12.

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