Method for metallization on p-type surface of crystalline silicon solar cell, and solar cell

Abstract

The present invention provides a method for metallization on a p-type surface of a crystalline silicon solar cell, and a solar cell. The method comprises: forming a first layer, comprising an aluminum metal or an aluminum-silicon alloy, on the p-type surface of the crystalline silicon solar cell; forming a second layer, comprising a nickel metal or a nickel-silicon alloy, on the first layer; and forming a third layer, comprising copper metal, on the second layer. By means of the method for metallization on the p-type surface of a solar cell and the solar cell of the present invention, a open-circuit voltage generated by the solar cell under an illumination condition can be effectively increased, thereby increasing the efficiency and performance of the solar cell in converting solar energy into electrical energy. Compared with technical solutions in the prior art in which nickel or copper is in direct contact with a p-type surface, the solar cell prepared by the method of the present invention can increase the open-circuit voltage by at least 5 mV.

Description

Method for metallizing the p-type surface of a crystalline silicon solar cell and solar cell Technical Field

[0001] The present invention relates to the field of solar cells, and in particular to a method for metallizing a p-type surface of a crystalline silicon solar cell and a solar cell. Background Art

[0002] A solar cell, also known as a photovoltaic cell, is a device that converts solar energy into electricity. Made of semiconductor materials, it converts solar energy into electricity through the photoelectric effect. Solar cells, typically composed of multiple solar cells, form panels and can be used for a variety of applications, including power generation, lighting, heating, and other electrical needs. The working principle of solar cells is that when sunlight strikes a semiconductor material, it excites electrons within it, generating an electric current. This current can be captured and harnessed, and connected to devices such as the panels and inverters, to convert solar energy into usable electricity. Solar cells are widely used worldwide due to their environmentally friendly, renewable, and low-maintenance properties. They can be installed in various locations, including rooftops, solar power plants, ships, and mobile devices, providing people with clean, renewable energy. With continuous technological advancements, the efficiency of solar cells continues to increase while their cost continues to decrease, making solar energy an increasingly popular energy option.

[0003] The p-type surface of a solar cell refers to the surface of the p-type semiconductor material in the solar cell. In solar cells, p-type semiconductor materials are typically doped with trivalent metals / semimetals, such as boron-doped silicon. The p-type surface is the positive electrode of the solar cell, forming a pn junction with the n-type semiconductor material, thus forming the solar cell structure. The p-type surface plays a vital role in solar cells and is a key component of photoelectric conversion. When light shines on the p-type surface of a solar cell, the photons excite electrons on the surface, forming electron-hole pairs. These electron-hole pairs separate under the electric field of the pn junction, generating current. To improve the efficiency of solar cells, the p-type surface is often treated to enhance its photoelectric conversion performance. Common surface treatment methods include oxidation, passivation, and the preparation of surface nanostructures. These methods can reduce surface reflection and improve photoelectric conversion efficiency.

[0004] However, when using electroplating to form an electrode on the p-type surface, nickel will come into direct contact with the p-type surface. This direct contact between nickel and the p-type surface will cause the solar cell's turn-on voltage to drop, thereby reducing the photoelectric conversion efficiency.

[0005] The purpose of the present invention is to solve the above-mentioned defect of decreased solar cell opening voltage caused by electroplating on the p-type surface of a crystalline silicon solar cell, thereby improving the photoelectric conversion efficiency of the solar cell. Summary of the Invention

[0006] The main purpose of the present invention is to provide a method for metallizing a p-type surface of a solar cell and a solar cell, so as to solve the problem of decreased photoelectric conversion efficiency of solar cells in the prior art.

[0007] To achieve the above-mentioned objectives, according to one aspect of the present invention, a method for metallization on the p-type surface of a crystalline silicon solar cell is provided, the method comprising: forming a first layer comprising aluminum metal or an aluminum-silicon alloy on the p-type surface of the crystalline silicon solar cell; forming a second layer comprising nickel metal or a nickel-silicon alloy on the first layer; and forming a third layer comprising copper metal on the second layer.

[0008] Furthermore, in the above method, the first layer is an aluminum-silicon alloy layer.

[0009] Furthermore, in the above method, the step of forming the aluminum-silicon alloy layer includes coating metal aluminum or aluminum oxide on the p-type surface of the solar cell, and using a laser to heat the metal aluminum or aluminum oxide and the p-type surface of the solar cell to generate an aluminum-silicon alloy.

[0010] Furthermore, in the above method, the second layer is a nickel-silicon alloy layer.

[0011] Furthermore, in the above method, the step of forming the nickel-silicon alloy layer includes electroplating nickel on the surface of the aluminum-silicon alloy layer, followed by sintering to generate the nickel-silicon alloy.

[0012] Furthermore, in the above method, the third layer is an electroplated copper layer.

[0013] Furthermore, in the above method, the method further includes forming a tin metal layer or a silver metal layer on the third layer.

[0014] Furthermore, in the above method, the surface of the solar cell further includes a barrier layer, and the barrier layer is located on the surface of the p-type doping layer opposite to the silicon base layer.

[0015] Furthermore, in the above method, the surface of the solar cell further includes a barrier layer, and the barrier layer is located on the surface of the p-type doping layer opposite to the silicon base layer.

[0016] According to another aspect of the present invention, a solar cell is provided. The solar cell is manufactured by the method of performing metallization on a p-type surface of the solar cell according to the present invention.

[0017] The present invention's method for metallizing the p-type surface of a solar cell and the solar cell it fabricates can effectively increase the turn-on voltage of the solar cell under illumination, thereby improving the efficiency and performance of the solar cell in converting solar energy into electrical energy. Compared to prior art solutions in which nickel or copper is directly in contact with the p-type surface, the solar cell fabricated using the present method can increase the turn-on voltage by at least 5 mV. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0019] 1 to 6 are schematic diagrams showing the preparation process of an embodiment of a method for metallizing a p-type surface of a crystalline silicon solar cell according to the present invention. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments of the present application and the features thereof may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] As described in the background, in the prior art, nickel directly contacts the p-type surface, resulting in a decrease in the solar cell's turn-on voltage and ultimately a reduction in the solar cell's photoelectric conversion efficiency. To address the problems of the prior art, according to a typical embodiment of the present application, a method for metallizing the p-type surface of a crystalline silicon solar cell is provided. The method includes forming a first layer comprising aluminum or an aluminum-silicon alloy on the p-type surface of the crystalline silicon solar cell; forming a second layer comprising nickel or a nickel-silicon alloy on the first layer; and forming a third layer comprising copper on the second layer.

[0022] Unlike prior art methods for treating the p-type surface of a solar cell, the metallization method of the present invention first forms a first layer comprising aluminum or an aluminum-silicon alloy on the p-type surface of the solar cell. The solar cell may comprise a silicon base layer, a p-type doped layer, and an optional barrier layer, wherein the p-type doped layer is located on one or both surfaces of the silicon base layer, and the optional barrier layer is located on the surface of the p-type doped layer opposite the silicon base layer. During the step of forming the first layer on the p-type surface of the solar cell, the first layer may be formed directly on the p-type doped layer or on the surface of the optional barrier layer. In a preferred embodiment, the first layer is composed of an aluminum-silicon alloy. Using aluminum or an aluminum-silicon alloy to form the first layer ensures that the metallization layer of the solar cell has excellent electrical conductivity, enabling efficient current transmission. It also provides corrosion resistance and maintains stable performance in harsh environmental conditions. Aluminum and aluminum-silicon alloys are relatively lightweight, reducing the weight of the solar cell and facilitating installation and portability. Furthermore, both aluminum and aluminum-silicon alloys are renewable materials, contributing to the environmental performance of the solar cell. In addition, unlike the technical solutions in the prior art that directly contact nickel or copper with the p-type surface, in the embodiments of the present invention, neither nickel nor copper is in direct contact with the p-type surface, but a first layer comprising aluminum metal or aluminum-silicon alloy is added between the two. The solar cell prepared by the above method can effectively increase the opening voltage that the solar cell can generate under light conditions, thereby improving the efficiency and performance of the solar cell in converting solar energy into electrical energy. Compared with the technical solutions in the prior art that directly contact nickel or copper with the p-type surface, the solar cell prepared by the method of the present invention can increase the opening voltage by at least 5mV.

[0023] After the first layer is formed, a second layer comprising nickel metal or nickel-silicon alloy is then formed on the first layer. In a preferred embodiment, the second layer is composed of nickel-silicon alloy. Nickel metal or nickel-silicon alloy has good corrosion resistance, can maintain the stability of solar cells under harsh environmental conditions, and extend the service life of solar cells. The formed second layer enables the metallization layer to have good electrical conductivity, can effectively transmit current, and improve the power conversion efficiency of solar cells. By using nickel metal or nickel-silicon alloy, the metallization layer has higher thermal stability, can maintain the stability of solar cells under high temperature conditions, and is conducive to the long-term stable operation of solar cells. In addition, nickel metal or nickel-silicon alloy has a lower cost than other materials, which can reduce the manufacturing cost of solar cells and improve their competitiveness.

[0024] After forming the second layer, a third layer comprising copper metal is formed on the second layer. Using copper as a metallization material for solar cells has the advantages of good conductivity, corrosion resistance, recyclability, and relatively low price, which is conducive to improving the performance of solar cells and reducing manufacturing costs.

[0025] In one embodiment of the present invention, a method for metallization on a p-type surface of a solar cell includes the following steps: step S1, applying an aluminum oxide layer or an aluminum layer on the surface of the p-type doped layer (and an optional barrier layer); step S2, using laser heating treatment to form an aluminum-silicon alloy (first layer) with a portion of the aluminum oxide layer or the aluminum layer and a portion of the silicon base layer, wherein the aluminum content in the aluminum-silicon alloy is about 15% to about 30%; step S3, removing the remaining portion of the aluminum oxide layer or the aluminum layer; and step S4, forming a gate line on the aluminum-silicon alloy, the gate line including at least a layer containing nickel elements (second layer), a layer containing copper elements (third layer) and an optional protective layer (fourth layer).

[0026] In the step of applying the aluminum oxide layer or the aluminum layer, the aluminum oxide layer or the aluminum layer may be applied to the barrier layer by sandblasting, spin coating, or spray coating. The applied aluminum oxide layer or the aluminum layer has a thickness of about 0.1 μm to about 1 μm. For different embodiments, the thickness of the aluminum oxide layer or the aluminum layer may be in the following ranges: about 0.1 μm to about 1 μm, about 0.15 μm to about 0.95 μm, about 0.2 μm to about 0.9 μm, about 0.25 μm to about 0.85 μm, about 0.3 μm to about 0.8 μm, about 0.35 μm to about 0.75 μm, about 0.4 μm to about 0.7 μm, about 0.45 μm to about 0.65 μm, about 0.5 μm to about 0.6 μm, about 0.1 μm to about 0.9 μm, about 0.1 μm to about 0.8 The thickness of the aluminum oxide layer or aluminum layer can be about 0.1 μm, about 0.1 μm to about 0.7 μm, about 0.1 μm to about 0.6 μm, about 0.1 μm to about 0.5 μm, about 0.1 μm to about 0.4 μm, about 0.1 μm to about 0.3 μm, about 0.1 μm to about 0.2 μm, about 0.2 μm to about 1 μm, about 0.3 μm to about 1 μm, about 0.4 μm to about 1 μm, about 0.5 μm to about 1 μm, about 0.6 μm to about 1 μm, about 0.7 μm to about 1 μm, about 0.8 μm to about 1 μm, or about 0.9 μm to about 1 μm. Within the above thickness range, the formed aluminum oxide layer or aluminum layer can effectively react with the silicon element in the silicon base layer to form a silicon-aluminum alloy layer of suitable thickness.

[0027] After applying the aluminum oxide layer or aluminum layer to the P-type doped layer, a laser heat treatment is performed to form an aluminum-silicon alloy with part (or all) of the aluminum oxide layer or aluminum layer and part of the solar cell (which may include part of the silicon substrate layer). In a further embodiment, the laser heat treatment can be performed at a temperature in the range of about 1300° C. to about 1500° C., preferably in the range of about 1400° C. to about 1500° C. For different embodiments, the laser heating process may be performed within the following temperature ranges: about 1300°C to about 1500°C, about 1310°C to about 1490°C, about 1320°C to about 1480°C, about 1330°C to about 1470°C, about 1340°C to about 1460°C, about 1350°C to about 1450°C, about 1360°C to about 1440°C, about 1370°C to about 1430°C, about 1380°C to about 1420°C, about 1390°C to about 1410°C, about 1300°C to about 1450°C, about 1300°C to about 1400°C, about 1300°C to about 1350°C, about 1350°C to about 1500°C, about 1400°C to about 1500°C, or about 1450°C to about 1500°C. Alternatively, in the case of laser treatment, the energy density of the laser treatment may be in the following ranges: about 1.5 J / cm2 to about 5 J / cm2, about 1.6 J / cm2 to about 4.9 J / cm2, about 1.7 J / cm2 to about 4.8 J / cm2, about 1.8 J / cm2 to about 4.7 J / cm2, about 1.9 J / cm2 to about 4.6 J / cm2, about 2.0 J / cm2 to about 4.5 J / cm2, about 2.3 J / cm2 to about 4.3 J / cm2, about 3.5 J / cm2 to about 4.0 J / cm2, about 1.5 J / cm2 to about 1.6 J / cm2, about 1.7 J / cm2 to about 1.8 J / cm2, about 1.8 J / cm2 to about 1.7 J / cm2, about 1.9 J / cm2 to about 1.6 J / cm2, about 2.0 J / cm2 to about 4.5 J / cm2, about 2.3 J / cm2 to about 4.3 J / cm2, about 3.5 J / cm2 to about 4.0 J / cm2, about 1.5 J / cm2 to about 1.6 J / cm2 The above temperature range or the above energy density range is as follows: the aluminum oxide layer or the aluminum layer can be effectively reacted with the silicon substrate layer of the solar cell thereunder to form a silicon-aluminum alloy layer, without causing changes in the properties of other layers, such as the P-type doped layer.

[0028] In the formed aluminum-silicon alloy, the aluminum content is in the range of about 15% to about 30%. A silicon-aluminum alloy layer within the above range can have excellent electrical conductivity, thereby making it easier for the current generated in the solar cell to be conducted through the metallization layer, thereby improving the photoelectric conversion efficiency of the solar cell. However, excessive aluminum content will increase the impedance of the silicon-aluminum alloy layer, adversely affecting the electrical performance of the solar cell, so aluminum should be included within the above range. For different embodiments, the aluminum content in the aluminum-silicon alloy can be selected within the following ranges: about 15% to about 30%, about 16% to about 29%, about 17% to about 28%, about 18% to about 28%, about 19% to about 27%, about 20% to about 26%, about 21% to about 25%, about 22% to about 24%, about 15% to about 25%, about 15% to about 20%, about 20% to about 30%, or about 25% to about 30%.

[0029] After forming the silicon-aluminum alloy layer, the unreacted aluminum oxide layer or aluminum layer can be removed to ensure light transmittance of the p-type surface of the solar cell. The remaining aluminum oxide layer or aluminum layer can be cleaned using a solvent, such as water or an organic solvent. In a preferred embodiment, water is used as the solvent to clean the remaining aluminum oxide layer or aluminum layer.

[0030] Subsequently, a layer containing nickel elements (second layer), a layer containing copper elements (third layer), and an optional protective layer (fourth layer) are formed on the aluminum silicon alloy. Nickel metal or nickel silicon alloy is first deposited on the aluminum oxide layer or the aluminum layer to form a second layer containing nickel elements. The second layer containing nickel elements can have a thickness of about 10 nm to about 1 μm. For different embodiments, the second layer can have a thickness in the following ranges: about 10 nm to about 1000 nm, about 50 nm to about 900 nm, about 100 nm to about 800 nm, about 150 nm to about 700 nm, about 200 nm to about 600 nm, about 250 nm to about 500 nm, about 300 nm to about 400 nm, about 10 nm to about 900 nm, about 10 nm to about 800 nm, about 10 nm to about 700 nm, about 10 The second layer may be formed by electroplating copper on the second layer to form a third layer comprising copper elements. The third layer comprising copper elements may have a thickness of about 5 μm to about 10 μm. According to different embodiments, the third layer containing copper elements may have a thickness within the following ranges: about 5 μm to about 10 μm, about 6 μm to about 9 μm, about 7 μm to about 8 μm, about 5 μm to about 9 μm, about 5 μm to about 8 μm, about 5 μm to about 7 μm, about 5 μm to about 6 μm, about 6 μm to about 10 μm, about 7 μm to about 10 μm, about 8 μm to about 10 μm, or about 9 μm to about 10 μm.

[0031] In an optional embodiment, elemental tin and / or elemental silver may be further deposited on the third layer comprising copper element to form a layer comprising tin metal and / or a layer comprising silver metal (fourth layer) to serve as a protective layer. The thickness of the fourth layer may be in the range of about 10 molecular layers to about 100 molecular layers. For different embodiments, the thickness of the fourth layer may be in the following ranges: about 10 molecular layers to about 100 molecular layers, about 20 molecular layers to about 90 molecular layers, about 30 molecular layers to about 80 molecular layers, about 40 molecular layers to about 70 molecular layers, about 50 molecular layers to about 60 molecular layers, about 20 molecular layers to about 100 molecular layers, about 30 molecular layers to about 100 molecular layers, about 40 molecular layers to about 100 molecular layers, about 50 molecular layers to about 100 molecular layers, about 60 molecular layers to about 100 molecular layers. The thickness of the metallized layer is preferably about 100 molecular layers thick, about 70 molecular layers thick to about 100 molecular layers thick, about 80 molecular layers thick to about 100 molecular layers thick, about 90 molecular layers thick to about 100 molecular layers thick, about 10 molecular layers thick to about 90 molecular layers thick, about 10 molecular layers thick to about 80 molecular layers thick, about 10 molecular layers thick to about 70 molecular layers thick, about 10 molecular layers thick to about 60 molecular layers thick, about 10 molecular layers thick to about 50 molecular layers thick, about 10 molecular layers thick to about 40 molecular layers thick, about 10 molecular layers thick to about 30 molecular layers thick, or about 10 molecular layers thick to about 20 molecular layers thick. In the case of including a protective layer, the silver or tin protective layer can prevent the surface of the metallized layer from being affected by corrosion, thereby extending the service life of the metallized layer; and can improve the conductive properties of the metallized layer, reduce resistance, and thus improve the efficiency and performance of the metallized layer. The silver or tin protective layer can also improve the chemical stability of the metallized layer, making it more durable and reliable.

[0032] In some embodiments of the present invention, the solar cell may further include an aluminum oxide layer disposed between the P-type doped layer and the barrier layer, and the aluminum oxide layer may have a thickness of approximately 5 nm to approximately 20 nm. In this embodiment, the aluminum oxide layer alone has the following advantages: it can form a protective film to prevent corrosion and oxidation of materials in the cell; it can improve the stability and durability of the solar cell, extending the cell's service life; it can reduce surface reflection and scattering, increasing light absorption efficiency, thereby improving the solar cell's photoelectric conversion efficiency; and it can improve the solar cell's photostability, reducing degradation of cell performance under light. According to various embodiments, the aluminum oxide layer may have a thickness within the following ranges: approximately 5 nm to approximately 20 nm, approximately 6 nm to approximately 19 nm, approximately 7 nm to approximately 18 nm, approximately 8 nm to approximately 17 nm, approximately 9 nm to approximately 16 nm, approximately 10 nm to approximately 15 nm, approximately 11 nm to approximately 14 nm, approximately 12 nm to approximately 13 nm, approximately 10 nm to approximately 20 nm, approximately 15 nm to approximately 20 nm, approximately 5 nm to approximately 15 nm, or approximately 5 nm to approximately 10 nm.

[0033] The solar cell of the present invention may have a barrier layer, which can be prepared using any material known in the art, such as silicon nitride (SiN), provided that the material of the barrier layer needs to have good transparency and passivation properties, thereby improving the efficiency of the solar cell. In a preferred embodiment, the barrier layer of the present invention comprises a silicon nitride (SiN) film layer and has a thickness of about 50nm to about 100nm. For different embodiments, the silicon nitride barrier layer has a thickness in the following range: 50nm to about 100nm, about 60nm to about 90nm, about 70nm to about 80nm, about 50nm to about 90nm, about 50nm to about 80nm, about 50nm to about 70nm, about 50nm to about 60nm, about 60nm to about 100nm, about 70nm to about 100nm, about 80nm to about 100nm, or 90nm to about 100nm.

[0034] The metallized layer prepared by the method of the present invention can be used as the gate line of the solar cell to connect the anode of the solar cell and the external circuit, and transmit the current generated by the solar cell to an external load or storage / transport equipment. The gate line prepared by the method of the present invention can also help adjust the opening voltage and current of the solar cell to better meet the needs of the external circuit. The gate line can also protect the battery from damage such as overload and short circuit. In the above-mentioned step of performing laser heat treatment, the width of the laser heat treatment (patterning) is the width of the gate line formed. The width of the gate line can be in the range of about 5μm to about 30μm. For different embodiments, the width of the gate line (the width of the laser heating treatment) can be in the following range: 5μm to about 30μm, about 6μm to about 29μm, about 7μm to about 28μm, about 8μm to about 27μm, about 9μm to about 26μm, about 10μm to about 25μm, about 13μm to about 22μm, about 15μm to about 20μm, about 17μm to about 18μm, about 5μm to about 25μm, about 5μm to about 20μm, about 5μm to about 15μm, about 5μm to about 10μm, about 10μm to about 30μm, about 15μm to about 30μm, about 20μm to about 30μm, or 25μm to about 30μm.

[0035] According to another exemplary embodiment of the present invention, a solar panel is provided, comprising: a silicon substrate layer; a p-type doped layer; a barrier layer; and patterned gate lines. In this solar panel, the p-type doped layer is located on at least one surface of the silicon substrate layer, the barrier layer is located on a surface of the p-type doped layer opposite the silicon substrate layer, and the patterned gate lines include at least a layer containing nickel, a layer containing copper, and an optional protective layer. The solar panel comprises a groove extending through the barrier layer and the p-type doped layer to the silicon substrate, with an aluminum-silicon alloy disposed at the bottom of the groove. The patterned gate lines are disposed within the groove and on the aluminum-silicon alloy, wherein the aluminum content of the aluminum-silicon alloy is approximately 15% to approximately 30%. The solar panel according to this embodiment is preferably fabricated using the method of metallizing the p-type surface of a solar cell according to the present invention. By employing the solar panel of the present invention, the nickel or copper is not in direct contact with the p-type surface, but rather a first layer containing aluminum or an aluminum-silicon alloy is added between the two. Solar cells fabricated using this method can effectively increase the breakover voltage generated by the solar cell under illumination, thereby improving the efficiency and performance of the solar cell in converting solar energy into electrical energy. Compared with the technical solution in the prior art in which nickel or copper is in direct contact with the p-type surface, the solar cell prepared by the method of the present invention can increase the opening voltage by at least 10 mV.

[0036] According to the solar panel of the invention, the solar panel may further include an aluminum oxide layer. The aluminum oxide layer is located between the P-type doped layer and the barrier layer. The aluminum oxide layer has a thickness of about 5 nm to about 20 nm. In a further embodiment, the barrier layer is a silicon nitride film layer, and the barrier layer has a thickness of about 50 nm to about 100 nm. In the solar panel of the present invention, the patterned gate line has a width between about 5 μm and about 30 μm; the nickel layer has a thickness of about 10 nm to about 1 μm; the copper layer has a thickness of about 5 μm to about 10 μm; the protective layer includes a layer containing tin metal and / or a layer containing silver metal, and the protective layer may have a thickness of about 10 molecular layers to about 100 molecular layers.

[0037] Example

[0038] Example 1

[0039] A crystalline silicon solar panel is provided, as shown in FIG1 . The panel includes a substrate (not shown), an n-type doped layer 101, a p-type doped layer 102, and a barrier layer 103 comprising SiN. The p-type doped layer has a thickness of approximately 0.1 micrometers (μm), and the SiN barrier layer has a thickness of approximately 0.08 μm. Referring to FIG2 , an aluminum oxide layer 104 is formed on one side of the p-type doped layer 102 of the solar panel by sandblasting nano-alumina powder. The aluminum oxide layer 104 has a thickness of approximately 100 nanometers (nm). Referring to FIG3 , the aluminum oxide layer 104 is laser-treated 105 using a UV picosecond laser scanning method. The laser treatment has an energy density of approximately 2.5 joules / square centimeter. Referring to FIG4 , after the laser treatment 105 , the nano-alumina powder layer is irradiated with laser energy, melting and destroying the silicon nitride barrier layer 103, thereby forming an aluminum-silicon alloy 201 with the silicon therein. The aluminum-silicon alloy has a thickness of approximately 0.1 μm and an aluminum content of approximately 30%. Water is used as a solvent to clean the remaining aluminum oxide layer 104. Referring to FIG5 , nickel is electroplated onto the silicon-aluminum alloy 201, wherein the nickel metal thickness is approximately 0.1 μm, and then sintered at a temperature of approximately 400° C. to form a nickel-silicon alloy layer 202, wherein the nickel-silicon alloy layer thickness is approximately 0.2 μm. Referring to FIG6 , copper is electroplated onto the nickel-silicon alloy to form a copper layer 203, wherein the copper layer thickness is approximately 8 μm.

[0040] Example 2

[0041] A crystalline silicon solar panel is provided, comprising a substrate, an n-type doped layer, a p-type doped layer, and a barrier layer comprising SiN, wherein the p-type doped layer has a thickness of approximately 0.12 μm, and the SiN barrier layer has a thickness of approximately 0.1 μm. A layer of nano-alumina sol is spin-coated on one side of the p-type doped layer of the solar panel to form an aluminum oxide layer having a thickness of approximately 150 nanometers (nm). The aluminum oxide layer is laser-treated using a UV picosecond laser scanning method, wherein the laser treatment has an energy density of approximately 3.5 joules / square centimeter. After the laser treatment, the nano-alumina sol is irradiated with laser energy and melts, destroying the silicon nitride barrier layer to form an aluminum-silicon alloy with the silicon therein, wherein the aluminum-silicon alloy has a thickness of approximately 0.15 μm and an aluminum content of approximately 25%. Water is used as a solvent to wash away the remaining aluminum oxide layer 104. Nickel metal is electroplated on the silicon-aluminum alloy, wherein the nickel metal has a thickness of about 0.1 μm, and then sintered at a temperature of 400° C. to form a nickel-silicon alloy layer, wherein the nickel-silicon alloy layer has a thickness of about 0.2 μm. Copper is electroplated on the nickel-silicon alloy to form a copper layer, wherein the copper layer has a thickness of about 8 μm.

[0042] Example 3

[0043] A crystalline silicon solar panel is provided, comprising a substrate, an n-type doped layer, a p-type doped layer, and a barrier layer comprising SiN, wherein the p-type doped layer has a thickness of approximately 0.15 μm, and the SiN barrier layer has a thickness of approximately 0.05 μm. A layer of nano-alumina sol is dip-coated on one side of the p-type doped layer of the solar panel to form an aluminum oxide layer having a thickness of approximately 200 nanometers (nm). The aluminum oxide layer is laser-treated using a continuous green laser scanning method, wherein the laser treatment has an energy density of approximately 3.0 joules / square centimeter. After the laser treatment, the nano-alumina sol is irradiated with laser energy and melts, destroying the silicon nitride barrier layer to form an aluminum-silicon alloy with the silicon therein, wherein the aluminum-silicon alloy has a thickness of approximately 0.2 μm and an aluminum content of approximately 30%. Water is used as a solvent to wash away the remaining aluminum oxide layer 104. Nickel metal is electroplated on the silicon-aluminum alloy, wherein the nickel metal has a thickness of about 0.1 μm, and then sintered at a temperature of 400° C. to form a nickel-silicon alloy layer, wherein the nickel-silicon alloy layer has a thickness of about 0.2 μm. Copper is electroplated on the nickel-silicon alloy to form a copper layer, wherein the copper layer has a thickness of about 8 μm.

[0044] Comparative Example 1

[0045] A crystalline silicon solar cell panel is provided. The panel includes a substrate, an n-type doped layer, a p-type doped layer, and a barrier layer comprising SiN, wherein the p-type doped layer has a thickness of approximately 0.1 μm, and the SiN barrier layer has a thickness of approximately 0.08 μm. Nickel is electroplated directly on the barrier layer, wherein the nickel metal has a thickness of approximately 0.1 μm, and then sintered at 400°C to form a nickel-silicon alloy layer, wherein the nickel-silicon alloy layer has a thickness of approximately 0.2 μm. Copper is electroplated on the nickel-silicon alloy to form a copper layer, wherein the copper layer has a thickness of approximately 8 μm.

[0046] Solar cell voltage detection

[0047] The opening voltages of the solar cells prepared in Examples 1-3 and Comparative Example 1 were measured using a Suns-Voc tester (Sinton minority carrier lifetime tester). The experimental results are shown in Table 1.

[0048] Table 1 Turn-on voltage of solar cells

[0049] The above experimental results demonstrate that the solar cells prepared using the method of the present invention can effectively increase the turn-on voltage generated by the solar cell under illumination, thereby improving the efficiency and performance of the solar cell in converting solar energy into electrical energy. Compared to prior art solutions that directly contact nickel or copper with the p-type surface, the solar cells prepared using the method of the present invention can increase the turn-on voltage by at least 5 mV. Compared to Comparative Example 1, Examples 1-3 of the present invention achieve increases of 5 mV, 8 mV, and 10 mV, respectively.

[0050] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for metallizing a p-type surface of a crystalline silicon solar cell, characterized in that: include: forming a first layer comprising aluminum metal or an aluminum-silicon alloy on a p-type surface of the crystalline silicon solar cell; forming a second layer comprising nickel metal or nickel-silicon alloy on the first layer; and A third layer including copper metal is formed on the second layer.

2. The method according to claim 1, characterized in that The first layer is an aluminum-silicon alloy layer.

3. The method according to claim 2, characterized in that The step of forming the aluminum-silicon alloy layer includes coating metal aluminum or aluminum oxide on the p-type surface of the solar cell, and using a laser to heat the metal aluminum or aluminum oxide and the p-type surface of the solar cell to generate the aluminum-silicon alloy.

4. The method according to claim 2, characterized in that The second layer is a nickel-silicon alloy layer.

5. The method according to claim 4, characterized in that The step of forming the nickel-silicon alloy layer includes electroplating nickel on the surface of the aluminum-silicon alloy layer, followed by sintering to generate the nickel-silicon alloy.

6. The method according to claim 1, characterized in that The third layer is an electroplated copper layer.

7. The method according to claim 1 or 6, characterized in that The method further includes forming a tin metal layer or a silver metal layer on the third layer.

8. The method according to any one of claims 1 to 6, characterized in that The solar cell further includes a barrier layer on its surface. The barrier layer is located on a surface of the p-type doping layer opposite to the silicon base layer.

9. The method according to claim 7, characterized in that The solar cell further includes a barrier layer on its surface. The barrier layer is located on a surface of the p-type doping layer opposite to the silicon base layer.

10. A solar cell, characterized in that: Prepared according to the method according to any one of claims 1 to 9.

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