Copper-containing metal electrode solar cell, solar cell module and preparation method

Abstract

The present invention discloses a copper-containing metal electrode solar cell, a solar cell module, and a preparation method, belonging to the field of solar cell technology. The copper-containing metal electrode solar cell includes a silicon wafer, a first semiconductor layer, a second semiconductor layer, a conductive film layer, a copper-containing metal fine grid electrode, and protective ink; a second semiconductor opening area is formed between adjacent first semiconductor layers; an isolation groove is provided on the conductive film layer corresponding to the edge area of ​​the second semiconductor opening area; a copper-containing metal fine grid electrode is provided on each conductive film layer corresponding to the first semiconductor layer and the second semiconductor layer; the protective ink covers the copper-containing metal fine grid electrode, and / or the protective ink covers the isolation groove; the refractive index of the protective ink is 1.4-2.2, and the average light transmittance at a wavelength of 300-1100nm is ≥80%. The present invention improves the long-term reliability of the module, while also reducing the technical requirements for packaging materials, effectively reducing product costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and in particular relates to a solar cell with a copper metal electrode, a solar cell module and a preparation method thereof. Background Art

[0002] Photovoltaic silver paste is primarily used to make grid lines for photovoltaic cells, affecting photoelectric conversion efficiency. The quality and conductivity of silver paste directly impact the performance and quality of solar cells. With the development of the photovoltaic industry, photovoltaic silver will account for over 16% of global silver demand in 2023, making it the largest disruptor of global silver demand. In 2024, the photovoltaic industry's demand for electronic-grade silver powder is expected to approach 7,000 tons. Against the backdrop of high silver prices, photovoltaic companies are accelerating silver paste cost reductions, which currently account for over 30% of the non-silicon material costs of photovoltaic cells.

[0003] In order to reduce the use of silver, silver-coated copper paste and even pure copper paste have received widespread attention. Silver-coated copper paste is generally composed of conductive fillers and organic polymers. Conductive fillers are generally silver-coated copper powder or specially treated copper powder, which mainly plays the role of conducting electrons and determines the conductive properties of the grid lines. Organic polymers are mainly composed of a variety of composite resins, solvents, curing agents and other additives. Resins such as epoxy resins and polyurethanes, after curing, serve as the molecular structure skeleton, connecting the left and right, and determine physical properties such as bonding strength. Solvents and additives are mainly used to adjust the viscosity and leveling properties of the slurry, and determine the printability of the slurry. The curing agent is mainly used to solidify the collective bonding phase. The various raw material components are made into a uniform slurry through high-speed stirring and three-roll grinding.

[0004] However, copper is very sensitive to water vapor and acid and alkali. Water vapor will oxidize the copper in the silver-coated copper paste or the copper paste to produce copper oxide, thereby reducing the conductivity of the grid line. Copper ions are also easy to diffuse and penetrate on the battery cell to form deep energy level recombination centers, thereby destroying the passivation effect and affecting battery performance. In addition, solar cell modules need to be used outdoors for a long time (generally required to be 30 years), so the outdoor reliability of copper-containing metal electrodes is very risky.

[0005] To reduce the impact of acid, alkali, and water vapor on silver-coated copper paste or copper paste batteries, the front and back of the module are currently encapsulated with heavy glass with low water vapor permeability. Polymers with high water vapor permeability and light weight cannot be used for encapsulation. In addition, a layer of waterproof glue (such as butyl glue, silicone, etc.) needs to be added around the glass. At the same time, the film used to encapsulate the module needs to be made of as neutral a material as possible, which increases the cost and difficulty of module packaging.

[0006] However, even with the above measures, the prior art silver-coated copper paste or copper paste cells still do not perform well enough in the DH reliability test of solar cells, and the long-term reliability of the modules is insufficient.

[0007] It should be noted that this part of the present invention only provides background technology related to the present invention and does not necessarily constitute prior art or public known technology. Summary of the Invention

[0008] The present invention provides a solar cell with copper metal electrodes, a solar cell module and a preparation method, which at least solves the problem of insufficient long-term reliability of the module caused by the contact reaction of water vapor, acid and alkali with copper during long-term use after the battery is made into a module in the prior art, resulting in copper oxidation and migration and diffusion.

[0009] In order to achieve the above-mentioned objectives, in a first aspect, the present invention provides a copper-containing metal electrode solar cell, comprising a silicon wafer, a first semiconductor layer, a second semiconductor layer, a conductive film layer, a copper-containing metal fine grid electrode and a protective ink; the silicon wafer has a back side and a front side; the first semiconductor layer and the second semiconductor layer are alternately arranged on the back side of the silicon wafer, and a second semiconductor opening area is formed between adjacent first semiconductor layers; the conductive film layer is laid on the first semiconductor layer and the second semiconductor layer, and an isolation groove is provided on the conductive film layer corresponding to the edge area of ​​the second semiconductor opening area; a copper-containing metal fine grid electrode is provided on each conductive film layer corresponding to the first semiconductor layer and the second semiconductor layer; the protective ink covers the copper-containing metal fine grid electrode, and / or the protective ink covers the isolation groove; wherein the refractive index of the protective ink is 1.4-2.2, and the average transmittance at a wavelength of 300-1100nm is ≥80%.

[0010] Preferably, the thickness of the protective ink is 10-100 μm, and the width of the protective ink is not less than 60 μm; when the protective ink is covered on the copper-containing metal fine gate electrode, the thickness of the protective ink is more than 5 μm greater than the thickness of the copper-containing metal fine gate electrode, and the width of the protective ink is more than 10 μm greater than the width of the copper-containing metal fine gate electrode.

[0011] Preferably, the width of the isolation groove is 0.03-0.2 mm; when the protective ink covers the isolation groove, the ratio of the width of the protective ink to the width of the isolation groove is (1-4):1.

[0012] Preferably, the protective ink comprises the following components in percentage by mass: 50%-80% base resin, 5%-15% solvent, and 0.5%-5% transmittance enhancer.

[0013] Preferably, the copper-containing metal electrode solar cell also includes a first insulating ink and a second insulating ink; the first insulating ink is arranged on the conductive film layer corresponding to the first semiconductor layer and is spaced apart along the length direction of the first semiconductor layer, and covers the copper-containing metal fine gate electrode; the second insulating ink is arranged on the conductive film layer corresponding to the second semiconductor layer and is spaced apart along the length direction of the second semiconductor layer, and covers the copper-containing metal fine gate electrode; wherein the first insulating ink and the second insulating ink are staggered and alternately arranged along the length direction of the first semiconductor layer and the second semiconductor layer.

[0014] Preferably, the copper-containing metal electrode solar cell also includes fine grid connection lines, and the fine grid connection lines are respectively arranged on a plurality of first insulating inks arranged at intervals along the length direction of the first semiconductor layer and a plurality of second insulating inks arranged at intervals along the length direction of the second semiconductor layer. The fine grid connection lines are perpendicular to the copper-containing metal fine grid electrodes; the fine grid connection lines are formed by silver-coated copper paste or solidified copper paste, and the mass content of copper in the silver-coated copper paste is greater than 40%.

[0015] Preferably, protective ink is provided on areas with a width W1 on both sides of the fine gate connection line.

[0016] Preferably, no protective ink is provided on the areas with a width W1 on both sides of the fine grid connection lines.

[0017] Preferably, the width W1 of both sides of the fine grid connection line is 0.1-4 mm.

[0018] Preferably, the length of the copper-containing metal fine gate electrode not provided with the protective ink accounts for less than 10% of the entire length of the copper-containing metal fine gate electrode.

[0019] Preferably, the length of the isolation groove where the protective ink is not provided is within 10% of the entire isolation groove length.

[0020] Preferably, the first semiconductor layer includes a tunneling oxide layer and a doped polycrystalline layer, and the second semiconductor layer includes an amorphous passivation layer and a doped amorphous layer.

[0021] Preferably, the copper-containing metal electrode solar cell further includes a front passivation layer and an anti-reflection layer, which are sequentially arranged on the front side of the silicon wafer.

[0022] On the other hand, the present invention also provides a method for preparing a solar cell containing a copper metal electrode, the preparation method comprising the following steps:

[0023] S101, forming alternately arranged first semiconductor layers and second semiconductor layers on the back side of a silicon wafer, and forming second semiconductor opening regions between adjacent first semiconductor layers;

[0024] S102, forming a conductive film layer on the first semiconductor layer and the second semiconductor layer;

[0025] S103, etching an opening on the conductive film layer corresponding to an edge region of the second semiconductor opening region to form an isolation trench;

[0026] S104, forming a copper-containing metal fine gate electrode on each of the conductive film layers corresponding to the first semiconductor layer and the second semiconductor layer;

[0027] S105 , covering the copper-containing metal fine gate electrode with protective ink, and / or covering the isolation trench with protective ink.

[0028] Preferably, S101 further includes: forming a front passivation layer and an anti-reflection layer on the front side of the silicon wafer.

[0029] Preferably, between S104 and S105, the following steps are further included:

[0030] S106. Alternately and staggeredly arrange the first insulating ink and the second insulating ink on the corresponding conductive film layers along the length direction of the first semiconductor layer and the second semiconductor layer; and respectively arrange fine gate connecting lines on the multiple first insulating inks arranged at intervals along the length direction of the first semiconductor layer and the multiple second insulating inks arranged at intervals along the length direction of the second semiconductor layer.

[0031] Preferably, S105 also includes staggered and alternating arrangement of a first insulating ink and a second insulating ink on the corresponding conductive film layer along the length direction of the first semiconductor layer and the second semiconductor layer; the first insulating ink, the second insulating ink and the protective ink are formed synchronously; and then fine gate connecting lines are respectively arranged on the multiple first insulating inks arranged at intervals along the length direction of the first semiconductor layer and the multiple second insulating inks arranged at intervals along the length direction of the second semiconductor layer.

[0032] On the other hand, the present invention also provides a copper metal electrode solar cell module, comprising a plurality of copper metal electrode solar cells, wherein the plurality of copper metal electrode solar cells are connected by welding ribbons to form a cell string; the copper metal electrode solar cell module also includes a backplane, a backside adhesive film, a frontside adhesive film, and a front plate; wherein the backplane, the backside adhesive film, the cell string, the frontside adhesive film, and the front plate are stacked and laminated in sequence to form a copper metal electrode solar cell module.

[0033] Preferably, the back sheet and the front sheet are each independently a glass or polymer sheet.

[0034] On the other hand, the present invention also provides a method for preparing a solar cell module containing a copper metal electrode, the preparation method comprising the following steps:

[0035] S201, providing a plurality of solar cells containing copper metal electrodes;

[0036] S202, connecting a plurality of solar cells containing copper metal electrodes using a welding ribbon to form a cell string;

[0037] S203, sequentially laying a back film, the battery string formed in S202, a front film, and a front plate on the surface of the back plate;

[0038] S204, laminating the back sheet, back film, cell string, front film, and front sheet laid out in S203 to form a solar cell module containing copper metal electrodes.

[0039] The beneficial effects of the present invention are:

[0040] 1. The present invention protects the copper-containing metal fine grid electrode by covering it with protective ink, preventing water vapor, acid and alkali from contacting and reacting with copper during long-term use after the battery is made into a module, thereby avoiding the migration and diffusion of copper ions, thereby improving the long-term reliability of the module. At the same time, it also reduces the technical requirements for packaging materials, effectively reduces product costs, and expands the application scenarios of packaging copper-containing metal electrode solar cells into modules.

[0041] 2. The present invention also protects the isolation grooves by using protective ink to prevent the isolation grooves from being directly exposed to the outside, thereby reducing environmental impacts on the battery cells, such as humidity, dust, chemicals, etc., thereby extending their service life.

[0042] 3. The protective ink provided in the present invention also has an anti-reflection effect, effectively improving the efficiency of the photovoltaic panel in receiving and converting light energy from the front and back sides (bifaciality), significantly reducing the reflection loss on the surface of the cell, so that more light energy is absorbed by the cell and converted into electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 A schematic cross-sectional view of a solar cell containing a copper metal electrode provided in Example 1 of the present invention;

[0045] Figure 2 A schematic plan view of a solar cell containing a copper metal electrode provided in Example 1 of the present invention;

[0046] Figure 3 A schematic plan view of forming a first insulating ink, a second insulating ink and fine grid connection lines on a solar cell containing a copper metal electrode provided in Example 1 of the present invention;

[0047] Figure 4 A schematic cross-sectional view of forming a protective ink on a solar cell containing a copper metal electrode, provided in Example 1 of the present invention;

[0048] Figure 5 A schematic plan view of forming a protective ink on a solar cell containing a copper metal electrode according to Example 1 of the present invention;

[0049] Figure 6 A schematic plan view of connecting a plurality of solar cells containing copper metal electrodes with a welding ribbon to form a cell string according to Example 1 of the present invention;

[0050] Figure 7 A schematic structural diagram of a solar cell module containing copper metal electrodes provided in Example 1 of the present invention;

[0051] Figure 8 A schematic cross-sectional view of forming a protective ink on a solar cell containing a copper metal electrode, provided in Example 2 of the present invention;

[0052] Figure 9 A schematic cross-sectional view of forming a protective ink on a solar cell containing a copper metal electrode, provided in Example 3 of the present invention;

[0053] Figure 10 A schematic plan view of forming a protective ink on a solar cell containing a copper metal electrode according to Example 8 of the present invention;

[0054] Figure 11 A schematic plan view of forming a first insulating ink, a second insulating ink, and a protective ink on a solar cell containing a copper metal electrode, provided in Example 11 of the present invention;

[0055] Figure 12 This is a schematic structural diagram of a solar cell module containing copper metal electrodes provided in Comparative Example 1 of the present invention;

[0056] Figure 13 This is a planar microscope image of a solar cell containing a copper metal electrode provided in Comparative Example 1 of the present invention;

[0057] Figure 14 A planar microscope image of a solar cell containing a copper metal electrode provided in Example 2 of the present invention;

[0058] Figure 15 This is an EL test image of the copper-containing metal electrode solar cell module DH1000 provided in Example 2 of the present invention before testing;

[0059] Figure 16 This is an EL test image of the copper metal electrode solar cell module DH1000 after testing provided in Example 2 of the present invention;

[0060] Figure 17This is an EL test image of the copper-containing metal electrode solar cell module DH1000 provided in Comparative Example 1 of the present invention before testing;

[0061] Figure 18 This is an EL test image of the copper-containing metal electrode solar cell module DH1000 provided in Comparative Example 1 of the present invention after testing;

[0062] Figure 19 A cross-sectional schematic diagram of forming a protective ink on a copper-containing metal electrode solar cell provided in Example 14 of the present invention.

[0063] Description of reference numerals:

[0064] 1. Silicon wafer; 2. Tunneling oxide layer; 3. Doped polycrystalline layer; 4. Amorphous passivation layer; 5. Doped amorphous layer; 6. Front passivation layer; 7. Anti-reflection layer; 8. Conductive film layer; 9. Copper-containing metal fine gate electrode; 10. Protective ink; 11. First insulating ink; 12. Second insulating ink; 13. Fine gate connecting wires;

[0065] 100. Copper metal electrode solar cell; 200. Solder ribbon; 300. Back sheet; 400. Back adhesive film; 500. Front adhesive film; 600. Front sheet; 700. Waterproof adhesive. DETAILED DESCRIPTION

[0066] In the present invention, unless otherwise specified, directional words such as "up, down, left, right" are generally understood in conjunction with the directions shown in the drawings and actual applications.

[0067] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0068] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0069] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein. The terms "optional" and "optional" mean that a range may or may not be included (or may or may not be present).

[0070] In a first aspect, the present invention provides a copper-containing metal electrode solar cell, comprising a silicon wafer, a first semiconductor layer, a second semiconductor layer, a conductive film layer, a copper-containing metal fine grid electrode and protective ink; the silicon wafer has a back side and a front side; the first semiconductor layer and the second semiconductor layer are alternately arranged on the back side of the silicon wafer, and a second semiconductor opening area is formed between adjacent first semiconductor layers; the conductive film layer is laid on the first semiconductor layer and the second semiconductor layer, and an isolation groove is provided on the conductive film layer corresponding to the edge area of ​​the second semiconductor opening area; a copper-containing metal fine grid electrode is provided on each conductive film layer corresponding to the first semiconductor layer and the second semiconductor layer; the protective ink covers the copper-containing metal fine grid electrode, and / or the protective ink covers the isolation groove; wherein the refractive index of the protective ink is 1.4-2.2, and the average transmittance at a wavelength of 300-1100nm is ≥80%.

[0071] It can be understood that the protective ink of the present invention can be covered only on the copper-containing metal fine gate electrode, or only on the isolation groove, or on both the copper-containing metal fine gate electrode and the isolation groove. Under the premise of pursuing the protective effect, the protective ink is preferably covered on both the copper-containing metal fine gate electrode and the isolation groove.

[0072] It is understood that although the present invention uses a hybrid passivated back-contact cell as an example, the technical solution of the present invention is not limited to the type of solar cell. It can be a cell with double-sided gridlines or a back-contact cell. The double-sided gridline cell can be a HJT (heterojunction cell), a Topcon (tunneling oxide passivated contact cell), a Perc (passivated emitter and back contact cell), etc. The back-contact cell can be a TBC (tunneling oxide passivated back contact cell), an HBC (heterojunction back-contact cell), etc. The protective ink of the present invention can be applied to the fine grids and / or isolation trenches on the back side of the back-contact cell, or to the fine grids on the front and / or back side of the double-sided gridline cell.

[0073] It is understood that the conductive film layer is a transparent conductive film or a composite film layer composed of a transparent conductive film and a metal conductive film. The transparent conductive film is indium oxide doped with zinc, tin, tungsten, titanium, or silicon, or zinc oxide doped with aluminum, boron, or gallium, and the metal conductive film is at least one of aluminum, copper, silver, a nickel alloy, and a titanium alloy.

[0074] It is understandable that the metal fine grid is formed by solidifying silver-coated copper paste or copper paste, and the mass content of copper in the silver-coated copper paste is greater than 40%. The silver-coated copper paste is composed of conductive fillers and organic polymers. The conductive filler is silver-coated copper powder or specially treated copper powder, which mainly plays the role of conducting electrons and determines the conductive properties of the grid line. Organic polymers are mainly composed of a variety of composite resins, solvents, curing agents and other additives. Resins such as epoxy resins and polyurethanes, after curing, serve as molecular structure skeletons, connecting left and right, and determine physical properties such as bonding strength. Solvents and additives are mainly used to adjust the viscosity and leveling properties of the slurry and determine the printability of the slurry. The curing agent is mainly used to solidify the collective bonding phase. The various raw material components are made into a uniform slurry through high-speed stirring and three-roll grinding.

[0075] The refractive index of the protective ink is 1.4-2.2, preferably 1.55-2.0. By ensuring that the refractive index of the protective ink is between that of the encapsulation material and the silicon-based semiconductor material, the present invention gradually transitions the refractive index of light within the multilayer structure. This significantly reduces surface reflection losses on the cell, allowing more light energy to be absorbed and converted into electrical energy by the cell, effectively improving the efficiency of the photovoltaic panel in receiving and converting light energy from both the front and back surfaces (bifaciality).

[0076] The protective ink has an average transmittance of 80% or greater at wavelengths between 300 and 1100 nm, and preferably 85% or greater at wavelengths between 300 and 1100 nm. Conventional silicon-based solar cells primarily absorb light in the 300-1100 nm wavelength range (visible and near-infrared). The high transmittance of the protective ink of the present invention ensures that light can penetrate the protective layer and enter the interior of the solar cell, preventing a decrease in photoelectric conversion efficiency due to absorption or scattering by the protective layer.

[0077] Preferably, the protective ink has a thickness of 10-100 μm and a width of no less than 60 μm. The present invention rationally controls the thickness and width of the protective ink, limiting the total volume of the protective ink (the amount of ink per unit area) to a reasonable range. This ensures that the protective ink has sufficient physical barrier properties to effectively prevent the penetration of water vapor, oxygen, and acidic and alkaline substances, while also preventing excessive ink from increasing material costs.

[0078] When the protective ink is applied to the copper-containing metal fine gate electrode, the thickness of the protective ink is at least 5 μm greater than the thickness of the copper-containing metal fine gate electrode, and the width of the protective ink is at least 10 μm greater than the width of the copper-containing metal fine gate electrode. This application ensures that the protective ink completely covers the edge area of ​​the electrode to prevent moisture from invading from the edge and causing copper oxidation. When the protective ink is applied to the copper-containing metal fine gate electrode, the cross-sectional shape of the protective ink can be semicircular, semi-elliptical, trapezoidal, etc.

[0079] Preferably, the width of the isolation groove is 0.03-0.2 mm; when the protective ink covers the isolation groove, the ratio of the width of the protective ink to the isolation groove is (1-4):1. The present invention controls the width of the isolation groove to ensure electrical isolation between the first semiconductor layer and the second semiconductor layer. Furthermore, when the protective ink covers the isolation groove, the ratio of the width of the protective ink to the isolation groove is controlled to ensure that the protective ink fully fills the groove, preventing residual contaminants or moisture accumulation within the groove.

[0080] It is understandable that the present invention does not limit the width of the protective ink. In extreme cases where a protective effect is desired, the conductive film layer except for the positions of the fine grid connection lines can be covered with the protective ink.

[0081] Preferably, the protective ink comprises the following components by mass percentage: 50%-80% base resin, 5%-15% solvent, and 0.5%-5% transmittance enhancer. The base resin may be selected from one or a combination of butyl resin, silicone resin, acrylic acid, and polyurethane. This base resin makes it easier to obtain a protective ink that meets the refractive index and average transmittance requirements. The transmittance enhancer is preferably a silicone resin, such as methylphenyl silicone resin, epoxy-modified silicone resin, or acrylic-modified silicone resin. By selecting an appropriate silicone resin and its content, the refractive index of the ink can be effectively adjusted to match the crystalline silicon cell, reducing interfacial reflection and increasing light transmittance, thereby improving the cell's bifaciality.

[0082] The solvent is selected from at least one of ketone, ester or alcohol ether organic solvents, such as cyclohexanone, propylene glycol methyl ether acetate (PMA), diethylene glycol butyl ether acetate (DBA) and the like.

[0083] It should be noted that other additives may be selectively added according to actual application scenarios without significantly changing the transmittance and refractive index baseline properties of the ink, including but not limited to dispersants, antioxidants, leveling agents, curing accelerators, coupling agents, etc.

[0084] Preferably, the copper-containing metal electrode solar cell also includes a first insulating ink and a second insulating ink; the first insulating ink is arranged on the conductive film layer corresponding to the first semiconductor layer and is spaced apart along the length direction of the first semiconductor layer, and covers the copper-containing metal fine gate electrode; the second insulating ink is arranged on the conductive film layer corresponding to the second semiconductor layer and is spaced apart along the length direction of the second semiconductor layer, and covers the copper-containing metal fine gate electrode; wherein the first insulating ink and the second insulating ink are staggered and alternately arranged along the length direction of the first semiconductor layer and the second semiconductor layer.

[0085] It can be understood that the first insulating ink and the second insulating ink are both resin inks, and the resin is preferably acrylic resin.

[0086] Preferably, the copper-containing metal electrode solar cell also includes fine grid connection lines, and the fine grid connection lines are respectively arranged on a plurality of first insulating inks arranged at intervals along the length direction of the first semiconductor layer and a plurality of second insulating inks arranged at intervals along the length direction of the second semiconductor layer. The fine grid connection lines are perpendicular to the copper-containing metal fine grid electrodes; the fine grid connection lines are formed by silver-coated copper paste or solidified copper paste, and the mass content of copper in the silver-coated copper paste is greater than 40%.

[0087] Preferably, the areas with a width W1 on both sides of the fine grid connection lines are provided with protective ink or are not provided with protective ink.

[0088] Preferably, the width W1 of both sides of the fine grid connection line is 0.1-4 mm.

[0089] It is understood that when protective ink is not applied to the areas of width W1 on both sides of the fine grid connection line (i.e., the protective ink gives way to the fine grid connection line), it is more convenient to manufacture the soldering ribbons connecting multiple copper metal electrode solar cells in the module. When protective ink is applied to the areas of width W1 on both sides of the fine grid connection line (i.e., the protective ink does not give way to the fine grid connection line), although the protective effect is better, the soldering ribbon may not contact the fine grid connection line properly when connecting the soldering ribbon.

[0090] Preferably, the length of the copper-containing metal fine gate electrode not covered with protective ink accounts for less than 10% of the entire length of the copper-containing metal fine gate electrode. The length of the isolation trench not covered with protective ink accounts for less than 10% of the entire length of the isolation trench. This configuration ensures the protective effect of the protective ink.

[0091] Preferably, the first semiconductor layer comprises a tunneling oxide layer and a doped polycrystalline layer, and the second semiconductor layer comprises an amorphous passivation layer and a doped amorphous layer. The thickness of the tunneling oxide layer or amorphous passivation layer, the doped polycrystalline layer and the doped amorphous layer and the corresponding doping concentrations of the present invention can refer to the ranges of the prior art, and can all be used in the present invention. For example, the thickness of the tunneling oxide layer is 1-2 nm, the thickness of the amorphous passivation layer is 3-10 nm; the thickness of the doped amorphous layer is 7-15 nm, and the effective doping concentration is 5e18 cm -3 -1e20cm -3 The thickness of the doped polycrystalline layer is 30-250nm, and the effective doping concentration is greater than 9e19cm -3 .

[0092] Preferably, the copper-metal-electrode solar cell further comprises a front passivation layer and an anti-reflection layer, which are sequentially disposed on the front surface of the silicon wafer. The types and thicknesses of the front passivation layer, anti-reflection layer, and mask layer described in the present invention can refer to the prior art and can all be used in the present invention. Exemplarily, the front passivation layer is at least one of amorphous silicon, microcrystalline silicon, silicon oxide, and polycrystalline silicon, and the anti-reflection layer is a silicon dielectric layer, which is at least one of silicon nitride, silicon oxide, silicon oxynitride, and intrinsic amorphous silicon.

[0093] On the other hand, the present invention also provides a method for preparing a solar cell containing a copper metal electrode, the preparation method comprising the following steps:

[0094] S101, forming alternately arranged first semiconductor layers and second semiconductor layers on the back side of a silicon wafer, and forming second semiconductor opening regions between adjacent first semiconductor layers;

[0095] S102, forming a conductive film layer on the first semiconductor layer and the second semiconductor layer;

[0096] S103, etching an opening on the conductive film layer corresponding to an edge region of the second semiconductor opening region to form an isolation trench;

[0097] S104, forming a copper-containing metal fine gate electrode on each of the conductive film layers corresponding to the first semiconductor layer and the second semiconductor layer;

[0098] S105 , covering the copper-containing metal fine gate electrode with protective ink, and / or covering the isolation trench with protective ink.

[0099] Preferably, S101 further includes: forming a front passivation layer and an anti-reflection layer on the front side of the silicon wafer.

[0100] Preferably, between S104 and S105, the following steps are further included:

[0101] S106. Alternately and staggeredly arrange the first insulating ink and the second insulating ink on the corresponding conductive film layers along the length direction of the first semiconductor layer and the second semiconductor layer; and respectively arrange fine gate connecting lines on the multiple first insulating inks arranged at intervals along the length direction of the first semiconductor layer and the multiple second insulating inks arranged at intervals along the length direction of the second semiconductor layer.

[0102] It is understandable that the first insulating ink, the second insulating oil, the protective ink and the fine grid connection lines can be formed by a printing or spraying process.

[0103] Preferably, S105 also includes staggered and alternating arrangement of a first insulating ink and a second insulating ink on the corresponding conductive film layer along the length direction of the first semiconductor layer and the second semiconductor layer; the first insulating ink, the second insulating ink and the protective ink are formed synchronously; and then fine gate connecting lines are respectively arranged on the multiple first insulating inks arranged at intervals along the length direction of the first semiconductor layer and the multiple second insulating inks arranged at intervals along the length direction of the second semiconductor layer.

[0104] It can be understood that when the first insulating ink, the second insulating ink and the protective ink are formed at the same time, the production efficiency is higher.

[0105] On the other hand, the present invention also provides a copper metal electrode solar cell module, comprising a plurality of copper metal electrode solar cells, wherein the plurality of copper metal electrode solar cells are connected by welding ribbons to form a cell string; the copper metal electrode solar cell module also includes a backplane, a backside adhesive film, a frontside adhesive film, and a front plate; wherein the backplane, the backside adhesive film, the cell string, the frontside adhesive film, and the front plate are stacked and laminated in sequence to form a copper metal electrode solar cell module.

[0106] Preferably, the back sheet and the front sheet are each independently a glass or polymer sheet.

[0107] It can be understood that when the backboard is a polymer board, it can be polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), etc.; when the front board is a polymer board, it can be ETFE (ethylene-tetrafluoroethylene copolymer), fluorocarbon resin, PVF (polyvinyl fluoride) and PVDF (polyvinylidene fluoride), etc.

[0108] On the other hand, the present invention also provides a method for preparing a solar cell module containing a copper metal electrode, the preparation method comprising the following steps:

[0109] S201, providing a plurality of solar cells containing copper metal electrodes;

[0110] S202, connecting a plurality of solar cells containing copper metal electrodes using a welding ribbon to form a cell string;

[0111] S203, sequentially laying a back film, the battery string formed in S202, a front film, and a front plate on the surface of the back plate;

[0112] S204, laminating the back sheet, back film, cell string, front film, and front sheet laid out in S203 to form a solar cell module containing copper metal electrodes.

[0113] The embodiments of the present invention are described in detail below, which are exemplary and only used to explain the present invention, and are not to be construed as limiting the present invention.

[0114] Example 1

[0115] A method for preparing a solar cell containing a copper metal electrode, the method comprising the following steps:

[0116] S101、 Figure 1 As shown, the first semiconductor layer and the second semiconductor layer are alternately arranged on the back side of the silicon wafer 1, a second semiconductor opening region is formed between adjacent first semiconductor layers, and a front passivation layer 6 and an anti-reflection layer 7 are formed on the front side of the silicon wafer 1;

[0117] like Figure 1 As shown, the first semiconductor layer includes a tunneling oxide layer 2 and a doped polycrystalline layer 3, and the second semiconductor layer includes an amorphous passivation layer 4 and a doped amorphous layer 5;

[0118] S102, such as Figure 1 As shown, a conductive film layer 8 is formed on the first semiconductor layer and the second semiconductor layer;

[0119] S103, such as Figure 1 As shown, an opening is etched on the conductive film layer 8 corresponding to the edge area of ​​the second semiconductor opening region to form an isolation trench;

[0120] The width of the isolation trench is 60 μm;

[0121] S104, such as Figure 1 and Figure 2 As shown, a copper-containing metal fine gate electrode 9 is formed on each conductive film layer 8 corresponding to the first semiconductor layer and the second semiconductor layer;

[0122] S106, such as Figure 3 As shown, first insulating ink 11 and second insulating ink 12 are staggered and alternately arranged on the corresponding conductive film layer 8 along the length direction of the first semiconductor layer and the second semiconductor layer; fine gate connection lines 13 are respectively arranged on the multiple first insulating inks 11 arranged at intervals along the length direction of the first semiconductor layer and the multiple second insulating inks 12 arranged at intervals along the length direction of the second semiconductor layer;

[0123] S105, such as Figure 4 and Figure 5As shown, a protective ink 10 is covered on the copper-containing metal fine grid electrode 9 to obtain the copper-containing metal electrode solar cell 100;

[0124] The refractive index of the protective ink 10 is 1.55-2.0, and the average light transmittance at a wavelength of 300-1100 nm is 90%;

[0125] The protective ink 10 has a thickness of 50 μm and a width of 200 μm;

[0126] The protective ink 10 is composed of 80% base resin, 15% solvent and 5% transmittance enhancer;

[0127] The protective ink 10 is not provided on the areas with a width W1 on both sides of the fine grid connection line 13 (ie, the protective ink 10 gives way to the fine grid connection line 13 ), and the width W1 on both sides of the fine grid connection line 13 is 2 mm.

[0128] A method for preparing a copper-containing metal electrode solar cell module from the obtained copper-containing metal electrode solar cell comprises the following steps:

[0129] S201、 Figure 6 As shown, a plurality of the above-mentioned copper-containing metal electrode solar cells 100 are provided;

[0130] S202, such as Figure 6 As shown, a plurality of solar cells 100 containing copper metal electrodes are connected by a welding ribbon 200 to form a cell string;

[0131] S203, such as Figure 7 As shown, the backside adhesive film 400, the battery string formed in S202, the front side adhesive film 500, and the front plate 600 are sequentially applied on the surface of the back plate 300;

[0132] S204, such as Figure 7 As shown, the back sheet 300, the back adhesive film 400, the cell string, the front adhesive film 500, and the front sheet 600 laid out in S203 are laminated to form a solar cell module containing copper metal electrodes;

[0133] The front panel 600 and the back panel 300 are both made of glass.

[0134] Example 2

[0135] The method of reference example 1 is carried out, except that, Figure 8 As shown, in S105 , the isolation groove is covered with protective ink 10 , but the copper-containing metal fine gate electrode 9 is not covered with protective ink 10 .

[0136] Example 3

[0137] The method of reference example 1 is carried out, except that, Figure 9As shown, in S105 , the isolation trench and the copper-containing metal fine gate electrode 9 are simultaneously covered with protective ink 10 .

[0138] Example 4

[0139] The method of Example 1 was followed, except that the thickness of the protective ink 10 was 10 μm.

[0140] Example 5

[0141] The method of Example 1 was followed, except that the thickness of the protective ink 10 was 100 μm.

[0142] Example 6

[0143] The method of Example 1 was followed, except that the width of the protective ink 10 was 60 μm.

[0144] Example 7

[0145] The method of Example 1 was followed, except that the width of the protective ink 10 was 300 μm.

[0146] Example 8

[0147] The method of reference example 1 is carried out, except that, Figure 10 As shown, the protective ink 10 is provided on the areas with a width W1 on both sides of the fine grid connection line 13 (ie, the protective ink 10 does not give way to the fine grid connection line 13).

[0148] Example 9

[0149] The method of Example 1 is referred to, except that the width W1 of both sides of the fine grid connection line 13 is 0.1 mm.

[0150] Example 10

[0151] The method of Example 1 is referred to, except that the width W1 of both sides of the fine grid connection line 13 is 4 mm.

[0152] Example 11

[0153] The method of reference example 1 is carried out, except that, Figure 11 As shown, S106 is not performed, and the first insulating ink, the second insulating ink and the protective ink are formed synchronously in S105.

[0154] Example 12

[0155] The method of Example 1 is referred to, except that the back plate 300 in S203 is a polymer plate.

[0156] Example 13

[0157] The method of Example 1 is referred to, except that the front plate 600 and the back plate 300 in S203 are both polymer plates.

[0158] Example 14

[0159] The method of reference example 2 is carried out, except that, Figure 19 As shown, a second semiconductor opening region is provided between adjacent first semiconductor layers. Both ends of the second semiconductor layer within the second semiconductor opening region extend a predetermined distance toward the surface of the adjacent first semiconductor layer and overlap with it to form an overlapping region. The first semiconductor layer has a first semiconductor opening region. A conductive film layer is laid over the first and second semiconductor layers, and isolation trenches are provided in the conductive film layer at each overlapping region.

[0160] Comparative Example 1

[0161] like Figure 12 As shown, a method for preparing a solar cell module containing copper metal electrodes comprises the following steps:

[0162] S101, providing a plurality of copper-containing metal electrode solar cells 100 (the difference from Example 1 is that the copper-containing metal electrode solar cells 100 in Comparative Example 1 are not provided with protective ink 10);

[0163] S102, connecting a plurality of solar cells 100 containing copper metal electrodes using a welding ribbon 200 to form a cell string;

[0164] S103, sequentially applying the backside adhesive film 400, the battery string formed in S102, the front side adhesive film 500, and the front side 600 on the surface of the backside plate 300; waterproof adhesive 700 is also applied around the area between the backside plate 300 and the front side 600, and the waterproof adhesive 700 can be butyl adhesive or silicone rubber;

[0165] S104, laminating the layers laid out in S103 to form a solar cell module containing copper metal electrodes;

[0166] The front panel 600 and the back panel 300 are both made of glass.

[0167] Test Case

[0168] The batteries and battery modules obtained from the above examples and comparative examples were subjected to performance testing, and the results are shown in Table 1. The DH1000 degradation test method involves conducting a reliability test in an environment with a constant temperature of 85°C and a relative humidity of 85% for 1000 hours, comparing the difference between the actual power output of the battery module and the theoretical power output.

[0169] Table 1

[0170]

[0171] It can be seen from the above results that, compared with the comparative example, the embodiment of the present invention, covering the electrodes and isolation grooves with protective ink, does not significantly affect the battery performance, but can greatly improve the attenuation of the battery module in the DH1000 reliability test.

[0172] Furthermore, according to Examples 1-14, it can be seen that the adoption of the preferred technical solution of the present invention is more conducive to improving battery performance and reliability.

[0173] Furthermore, if Figure 13 and Figure 14 As shown, under a microscope, in Example 2, a protective ink with a width of 200 μm is added to cover the isolation groove.

[0174] like Figure 15 and Figure 16 As shown, the EL test image of the battery module of Example 2 did not change significantly before and after the DH1000 reliability test, indicating excellent reliability.

[0175] like Figure 17 and Figure 18 As shown, the battery module of Comparative Example 1 has obvious blackening and penetration at the edges in the EL test image after the DH1000 reliability test, indicating insufficient reliability.

[0176] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A solar cell containing a copper metal electrode, characterized in that: include: a silicon wafer having a back side and a front side; A first semiconductor layer and a second semiconductor layer, wherein the first semiconductor layer and the second semiconductor layer are alternately arranged on the back surface of the silicon wafer, and a second semiconductor opening region is formed between adjacent first semiconductor layers; A conductive film layer, the conductive film layer being laid on the first semiconductor layer and the second semiconductor layer, and an isolation groove being opened on the conductive film layer at an edge area corresponding to the second semiconductor opening region; A copper-containing metal fine gate electrode is provided on each of the conductive film layers corresponding to the first semiconductor layer and the second semiconductor layer; Protective ink, the protective ink covers the copper-containing metal fine gate electrode, or the protective ink covers the copper-containing metal fine gate electrode and the isolation trench; The protective ink has a refractive index of 1.4-2.2 and an average light transmittance of ≥80% at a wavelength of 300-1100 nm; The protective ink comprises the following components in percentage by mass: base resin 50%-80%, solvent 5%-15%, and permeability enhancer 0.5%-5%; The length of the copper-containing metal fine gate electrode on which the protective ink is not provided is within 10% of the entire length of the copper-containing metal fine gate electrode; and / or, the length of the isolation groove on which the protective ink is not provided is within 10% of the entire length of the isolation groove.

2. The copper-containing metal electrode solar cell according to claim 1, characterized in that: The thickness of the protective ink is 10-100 μm, and the width of the protective ink is not less than 60 μm; When the protective ink covers the copper-containing metal fine gate electrode, the thickness of the protective ink is more than 5 μm greater than the thickness of the copper-containing metal fine gate electrode, and the width of the protective ink is more than 10 μm greater than the width of the copper-containing metal fine gate electrode.

3. The copper-containing metal electrode solar cell according to claim 2, characterized in that: The width of the isolation groove is 0.03-0.2 mm; When the protective ink covers the isolation groove, the ratio of the width of the protective ink to the width of the isolation groove is (1-4):

1.

4. The copper-containing metal electrode solar cell according to claim 1, characterized in that: The copper-containing metal electrode solar cell further comprises: A first insulating ink, wherein the first insulating ink is disposed on the conductive film layer corresponding to the first semiconductor layer and is spaced apart along the length direction of the first semiconductor layer, and covers the copper-containing metal fine gate electrode; a second insulating ink, the second insulating ink being disposed on the conductive film layer corresponding to the second semiconductor layer and spaced apart along the length direction of the second semiconductor layer, and covering the copper-containing metal fine gate electrode; The first insulating ink and the second insulating ink are alternately arranged in a staggered manner along the length direction of the first semiconductor layer and the second semiconductor layer.

5. The copper-containing metal electrode solar cell according to claim 4, characterized in that: The copper-containing metal electrode solar cell further comprises: Fine gate connection lines are respectively provided on a plurality of first insulating inks spaced apart along the length direction of the first semiconductor layer and a plurality of second insulating inks spaced apart along the length direction of the second semiconductor layer, and the fine gate connection lines are perpendicular to the copper-containing metal fine gate electrodes; The fine grid connection line is formed by silver-coated copper paste or solidified copper paste, and the mass content of copper in the silver-coated copper paste is greater than 40%.

6. The copper-containing metal electrode solar cell according to claim 5, characterized in that: The protective ink is provided on areas with a width W1 on both sides of the fine grid connection line.

7. The copper-containing metal electrode solar cell according to claim 5, characterized in that: The protective ink is not provided on the areas with a width W1 on both sides of the fine grid connection line.

8. The copper-containing metal electrode solar cell according to claim 6 or 7, characterized in that: The width W1 of both sides of the fine grid connection line is 0.1-4 mm.

9. The copper-containing metal electrode solar cell according to claim 1, characterized in that: The first semiconductor layer comprises a tunneling oxide layer and a doped polycrystalline layer, and the second semiconductor layer comprises an amorphous passivation layer and a doped amorphous layer; and / or, The copper-containing metal electrode solar cell further comprises: A front passivation layer and an anti-reflection layer are sequentially arranged on the front side of the silicon wafer.

10. A method for preparing a solar cell containing a copper metal electrode, characterized in that: The preparation method is used to prepare a copper-containing metal electrode solar cell according to any one of claims 1 to 9, and the preparation method comprises the following steps: S101, forming alternately arranged first semiconductor layers and second semiconductor layers on the back side of a silicon wafer, and forming second semiconductor opening regions between adjacent first semiconductor layers; S102, forming a conductive film layer on the first semiconductor layer and the second semiconductor layer; S103, etching an opening on the conductive film layer corresponding to an edge region of the second semiconductor opening region to form an isolation trench; S104, forming a copper-containing metal fine gate electrode on each of the conductive film layers corresponding to the first semiconductor layer and the second semiconductor layer; S105 , covering the copper-containing metal fine gate electrode with protective ink, and / or covering the isolation trench with protective ink.

11. The method for preparing a solar cell containing a copper metal electrode according to claim 10, wherein: S101 also includes: forming a front passivation layer and an anti-reflection layer on the front side of the silicon wafer.

12. The method for preparing a solar cell containing a copper metal electrode according to claim 10, wherein: Also included between S104 and S105: S106. The first insulating ink and the second insulating ink are alternately arranged on the corresponding conductive film layers along the length direction of the first semiconductor layer and the second semiconductor layer; fine gate connecting lines are respectively arranged on the multiple first insulating inks arranged at intervals along the length direction of the first semiconductor layer and the multiple second insulating inks arranged at intervals along the length direction of the second semiconductor layer.

13. The method for preparing a solar cell containing a copper metal electrode according to claim 10, wherein: S105 also includes staggered and alternating arrangement of first insulating ink and second insulating ink on the corresponding conductive film layers along the length direction of the first semiconductor layer and the second semiconductor layer; the first insulating ink, the second insulating ink and the protective ink are formed synchronously; and then fine gate connection lines are respectively arranged on multiple first insulating inks spaced apart along the length direction of the first semiconductor layer and multiple second insulating inks spaced apart along the length direction of the second semiconductor layer.

14. A solar cell module containing copper metal electrodes, characterized in that: Comprising a plurality of solar cells containing copper metal electrodes according to any one of claims 1 to 9, wherein the plurality of solar cells containing copper metal electrodes are connected by welding ribbons to form a cell string; The copper metal electrode solar cell module further comprises a back sheet, a back adhesive film, a front adhesive film, and a front sheet; The back sheet, the backside adhesive film, the cell string, the front side adhesive film, and the front sheet are stacked and laminated in sequence to form the copper-containing metal electrode solar cell module.

15. The copper-containing metal electrode solar cell module according to claim 14, characterized in that: The back plate and the front plate are each independently a glass or polymer plate.

16. A method for preparing a solar cell module containing copper metal electrodes, characterized in that: The preparation method is used to prepare the copper-containing metal electrode solar cell module according to claim 14, and the preparation method comprises the following steps: S201, providing a plurality of copper-containing metal electrode solar cells according to any one of claims 1 to 9; S202, connecting the plurality of copper-containing metal electrode solar cells using a welding ribbon to form a cell string; S203, sequentially laying a back film, the battery string formed in S202, a front film, and a front plate on the surface of the back plate; S204, laminating the back sheet, back film, cell string, front film, and front sheet laid out in S203 to form a solar cell module containing copper metal electrodes.

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