Method for fabricating a metal grid on the upper surface of a target layer in a layer stack and its application

Abstract

This application discloses a method for fabricating a narrow linear structure on the upper surface of a target layer of a layer stack, and its applications. The method for fabricating the linear structure includes the steps of: obtaining preset positions, designated as first and second lateral positions, on both sides of the linear structure on the upper surface of the target layer; generating a plurality of protrusions spaced apart along a lateral longitudinal direction at at least one of the first and second lateral positions on the upper surface of the target layer to form a protruding line at at least one lateral position; and applying and depositing a liquid linear structure material on one side of the protruding line to obtain a linear structure enclosed on one side of the protruding line.

Description

Technical Field

[0001] This application relates to the field of thin film solar cell technology, and more particularly, to a method for fabricating narrow linear structures on the upper surface of a target layer of a layer stack and its applications.

Background Art

[0002] Thin film solar cells have a multi-layer structure. As is well known to those skilled in the art, the layer structure of a thin film solar cell, in a substrate configuration, is composed of at least a substrate, a back electrode layer, an absorber layer, a buffer layer, and a front electrode layer, in order from bottom to top. In the case of a superstrate configuration, it is reversed but composed of the same layers. In the case of large-area thin film solar cells, in order to avoid high series resistance and subsequent high current losses, the module is usually designed as a series of monolithic interconnected cells. To achieve partitioning and series connection, P1, P2, and P3 lines are respectively disposed on the back electrode layer, absorber layer, buffer layer, and front electrode layer (as shown in FIG. 1). Specifically, the method for fabricating a thin film solar cell includes providing a substrate; depositing a back electrode layer on one side of the substrate; sub-dividing the back electrode layer with P1 lines; sequentially depositing an absorber layer and a buffer layer on the back electrode layer; simultaneously sub-dividing the absorber layer and the buffer layer with P2 lines; depositing a front electrode layer on the buffer layer; sub-dividing the front electrode layer with P3 lines.

[0003] P1 and P3 insulate the back electrode and the front electrode, and P2 functions as an electrical contact between the back electrode and the front electrode, thereby connecting two adjacent cells in series. Since the P1 / P2 / P3 structural regions do not generate electricity, they are usually referred to as the "dead regions" of the solar cell (as shown in FIGS. 1 and 3). The remaining regions are referred to as the active regions of the solar cell.

[0004] To optimize the power conversion efficiency and application performance of solar cells, it is sometimes preferable to add a linear structure to the upper surface of one layer. Considering that the width, thickness, and coverage area of ​​the linear structure on the layer surface affect the electrical and optical properties of the solar cell, it is necessary to limit the position of the linear structure on both sides, its thickness, and other parameters. The object of this application is to provide a method for fabricating a linear structure that allows for easy control and limitation of the position of the linear structure on its sides, its thickness, and other parameters.

[0005] To optimize the power conversion efficiency of a solar cell, a common approach is to increase the transmittance of the front electrode by reducing the thickness of the front electrode layer, thereby increasing the resulting photocurrent. However, this increases the sheet resistance of the front electrode, thus increasing conduction losses. To reduce these conduction losses in the front electrode layer, a narrow, highly conductive metal grid wire can be applied to the front electrode layer to improve its conductivity; this is called a metallization process for photovoltaic production. Therefore, as shown in Figures 3, 4, and 5, the metal grid wire G1 is applied at periodic intervals, either laterally to the cell or perpendicular to P1 / P2 / P3. These grid wires G1 are applied continuously to the solar cell. P3 prevents short circuits between the front electrode of one cell and its adjacent cells by interrupting the grid wire G1.

[0006] As shown in Figure 6, in the case of a monolithic interconnected cell, the current collected by the metal grid wire G1 and flowing toward the end of the cell is directly connected to the back electrode of the next cell via the P2 wire. The metal grid wire G1 reduces conduction losses due to the thinned front electrode, thereby offsetting the increase in series resistance. However, the shadow cast by the opaque metal grid wire also causes an increase in dead zones.

[0007] The shadow area of ​​the underlying absorber layer is determined by the width and length of the metal grid wire G1. While the length of the metal grid wire G1 should not be altered to account for the beneficial carrier collection effect of the metal grid wire and thinner front electrodes (increasing photocurrent without increasing series resistance), the width and thickness of the metal grid wire G1 can be optimized to reduce the shadow area and improve the photocurrent and efficiency of the solar cell. The relationship between the thickness and width of the metal grid wire G1 is called the aspect ratio. The series resistance of the metal grid wire G1 is determined by the specific series resistance and cross-sectional area of ​​the material. Therefore, to improve the efficiency of the solar cell, it is necessary to reduce light shielding by decreasing the width of the metal grid wire G1 and prevent conduction losses by increasing the thickness of the metal grid wire G1. Generally speaking, the purpose of using metal grid wire G1 is to improve the generated photocurrent and solar cell efficiency by applying a wire with minimal width and sufficient thickness, while reducing shadows caused by the metal grid wire G1 and keeping the series resistance low.

[0008] As shown in Figure 6, in the case of a monolithic interconnect cell, the current needs to be collected on the metal grid lines toward the end of the cell and evenly distributed at the beginning of the next cell. Otherwise, the front and back electrodes will cause further conductivity losses. Therefore, an additional metal grid line G2 can be used in the dead region. As shown in Figures 14 and 15, the metal grid line G2 is perpendicular to the metal grid line G1 and deposited directly above or parallel to the P2 structural line. The purpose of coating G2 is to evenly distribute the current and reduce electrical losses along the P2 interconnect between two adjacent cells caused by high current collection on the G1 metal grid line and point connections to P2, as shown in Figures 16 and 17. Since G2 is located in the dead region, it does not cause additional light loss due to shadows. Furthermore, this can improve the generation of photocurrent by reflecting light from the grid line G2 to the back surface of the coating layer / front glass and further incident on the absorber layer.

[0009] Therefore, precise deposition of G2 lines is necessary for accurate electrical and optical control in the dead zone. Furthermore, deposition of G2 at the edges of P1 and P3 lines can cause current separation in the active cell region. Additionally, mechanical scribing of the P3 pattern line can mechanically tear G2 lines or mask areas designated for the laser P3 line, resulting in discontinuities in the P3 line and thus current separation. Generally speaking, it is crucial to ensure that G2 lines are contained within the boundaries of the P2 pattern line. G2 lines that are significantly wider than P2 lines will increase the dead zone.

[0010] Furthermore, conventional methods for manufacturing metal grids, such as ALD (Aluminum Line Deposit) proposed by Solibro, involve depositing an aluminum wire structure by combining thermal deposition and a mask. The resulting structure is shown in Figure 7. The various drawbacks of this method are as follows: 1) low throughput and yield due to the use of a mask, 2) high cost of this special mask for manufacturing large-area modules, 3) high material waste due to deposition, 4) high workload for mask maintenance, which is most important for the efficiency of solar cells, and 5) limitations on the width (and aspect ratio) of the metal grid wires (mask openings that are too narrow, less than a few hundred micrometers, are prone to clogging during or after use).

[0011] For example, Nice Solar employs screen printing to deposit metal grid lines. However, screen printing is not suitable for large-area printing due to significant technical limitations. Large printing patterns can result in lower deposition accuracy and poor line shape (wider lines), especially in the central area of ​​large printing regions (>1m²), due to the lower rigidity (bending) of the center of large screens. Furthermore, printing narrow lines using screen printing requires high-quality screens, such as hardened and calendered stainless steel screens or knotless screens. For full-size thin-film solar cell modules (e.g., >1m²), these high-quality, large screens are extremely difficult to manufacture (fewer than two suppliers worldwide capable of producing them) and very expensive. In addition, screens used in the screen printing process are prone to clogging and difficult to clean. In addition to the high cost of screen printing for large thin-film modules, modifying the grid line printing pattern is also very inflexible if the line pitch needs to be adjusted during the production process.

[0012] Other process methods for manufacturing metal grids, such as aerosol jet printing or dispensing, are newer technologies for the metallization process, but they still suffer from serious process stability issues. Nozzles used in aerosol sprays or dispensers are prone to clogging with metal particles during prolonged printing, potentially causing frequent process downtime. Furthermore, these two methods can print up to 5-10 grid lines simultaneously. When printing on large-area thin-film modules, multiple printing runs are required. Currently, the throughput of aerosol jet printing is very low due to the difficulty of horizontal paste / aerosol distribution within the print head, making it extremely difficult to further increase the number of nozzles for dispensing or aerosol spraying. Currently, 10 nozzles effectively represent a bottleneck in both of these technologies.

[0013] Other process methods for manufacturing metal grids, such as inkjet printing, involve printing a printing solvent-based ink or paste onto the surface of the front electrode layer to form metal grid lines. Because inkjet printing is a digital printing technology (e.g., PCT / CN2022 / 074345), it is suitable for various line shapes or forms. This makes it particularly suitable for large-scale applications in thin-film photovoltaic power generation. One of the main drawbacks of this technology is that the ink composition contains small amounts of metal particles and large amounts of solvent. This typically results in broad, thin lines on the top of the front electrodes of solar cells. Furthermore, due to the coffee ring effect, as shown in Figure 8, the edges of the sprayed ink lines are thicker than the center of the lines.

[0014] In conventional technology, solvent-based inks or pastes are commonly used to form metal grid lines on the surface of the front electrodes of solar cells. The width of the metal grid lines is highly dependent on the surface tension and wettability of the ink or paste, which severely limits the use of materials as front electrodes and / or surface formation and / or surface treatment for optimal aspect ratio. Furthermore, heating a large portion of the metal grid lines is necessary to remove the solvent and improve conductivity, which can alter the shape of the wiring after the metal grid lines have been deposited. Solvent-based inks or pastes consist of a certain ratio of metal and solvent. In one method, simply reducing the ratio of solvent to metal (changing the composition) can reduce the line width, but this method can cause clogging of the print head or screen. In another method, using less material (smaller droplets) can reduce the line width, but this method simultaneously causes thinning of the metal grid lines, thus increasing the series resistance. To overcome this problem, multi-coating solutions can usually maintain a small line width while increasing the thickness of the metal lines. However, this method exhibits significant drawbacks, especially in high-speed applications used for high throughput in mass production. This is because the alignment of the generated lines is extremely important, and variations in the generated lines occur. [Overview of the project] [Problems that the invention aims to solve]

[0015] In view of the problems of the prior art, this application provides a method for fabricating a narrow linear structure on the upper surface of a target layer of a layer stack and its applications. Multiple protrusions are formed on the side surface of the linear structure to form a protruding line. The protruding line can be used to restrict the lateral position of the linear structure so that it can be contained on one or both sides. Therefore, when the linear structure is contained on both sides, the width, thickness, and position of the linear structure can be restricted, thereby enabling control and optimization of the shape of the linear structure. Alternatively, when the linear structure is contained on one side, the position of the linear structure can be restricted, preventing the linear structure from obscuring a portion of the lower film layer or the target area. The technical solution of this application is as follows. [Means for solving the problem]

[0016] In a first embodiment, a method is provided for fabricating a narrow linear structure on the upper surface of a target layer of a layer stack comprising at least two layers, which is applied to a process for fabricating a thin-film photovoltaic module. The method for fabricating the linear structure is as follows: A step of obtaining pre-set positions, which are designated as a first lateral position and a second lateral position, on both sides of the linear structure on the upper surface of the target layer, The steps include: forming a protruding line at at least one of the first and second lateral positions on the upper surface of the target layer by generating a plurality of protrusions spaced apart along the lateral longitudinal direction; The method includes the step of applying and depositing a liquid linear structural material on one side of the protruding line to obtain a linear structure enclosed on one side by the protruding line.

[0017] In some embodiments, the method for producing a linear structure is: When a plurality of protrusions are formed at intervals along the lateral longitudinal direction at the first lateral position and the second lateral position on the upper surface of the target layer, respectively, to form a first protruding line and a second protruding line, a liquid-type linear structure material is applied and deposited between the first protruding line and the second protruding line, thereby obtaining a linear structure confined between the first protruding line and the second protruding line, that is, a linear structure confined on both sides, or When a plurality of protrusions are formed at intervals along the lateral longitudinal direction at one of the confined lateral positions of the first lateral position and the second lateral position on the upper surface of the target layer to form a third protruding line, a liquid-type linear structure material is applied and deposited on one side of the third protruding line, thereby obtaining a linear structure confined on the one side of the third protruding line.

[0018] In some embodiments, the distance between two adjacent protrusions on the same protruding line is small enough to prevent the linear structure material from overflowing from one side of the protruding line to the other side during the deposition of the linear structure material.

[0019] In some embodiments, the distance between two adjacent protrusions on the same protruding line is less than 10 micrometers.

[0020] In some embodiments, when the linear structure is confined on both sides, the protrusions of the first protruding line and the protrusions of the second protruding line are asymmetric along the center line between the first protruding line and the second protruding line.

[0021] In some embodiments, when the linear structure is confined on both sides, the protrusions of the first protruding line and the protrusions of the second protruding line are symmetric along the center line between the first protruding line and the second protruding line.

[0022] In some embodiments, the distance between two adjacent protrusions on the same protruding line is uniform.

[0023] In some embodiments, the distance between two adjacent protrusions on the same protruding line is non-uniform.

[0024] In some embodiments, the height of the protrusion is large enough to prevent the material for forming the linear structure from overflowing from the protrusion during the formation of the linear structure.

[0025] In some embodiments, the height of the protrusion is determined based on the characteristic parameters of the material for forming the linear structure.

[0026] In some embodiments, the characteristic parameters of the material for forming the linear structure must be correctly selected and include at least the amount, viscosity, and surface tension of the material.

[0027] In some embodiments, the height of the protrusion is greater than 100 nanometers.

[0028] In some embodiments, the method for generating the protrusion includes irradiating a pulsed laser from above the target layer and irradiating the upper surface of the target layer so as to satisfy preset process parameters, such that the pulsed laser passes through the target layer and reaches the interface between two adjacent layers among the plurality of layers under the target layer, thereby melting and evaporating a part of the layer material at the interface between the two adjacent layers to form an upward protrusion.

[0029] In some embodiments, the preset process parameters of the pulsed laser satisfy the condition that the wavelength of the pulsed laser is greater than the optical bandgap of the target layer but smaller than the optical bandgap of at least one of the plurality of layers under the target layer.

[0030] In some embodiments, among the pre-set process parameters of the pulsed laser, the laser power of the pulsed laser is determined based on the thickness of the target layer and the characteristic parameters of the material of the target layer.

[0031] In some embodiments, the property parameters of the target layer material include at least the hardness, stiffness, tension, and adhesiveness of the front electrode layer material.

[0032] In some embodiments, the method for applying the liquid linear structural material includes, but is not limited to, inkjet printing, aerosol spraying, screen printing, and dispensing.

[0033] In a second embodiment, applications of a method for producing linear structures are provided, including applications in single-pass and / or multi-pass coating of liquid linear structural materials.

[0034] In a third embodiment, a method is provided for fabricating a metal grid wire based on an improved surface structure of a front electrode, wherein the target layer is a front electrode layer, the plurality of layers below the target layer include a buffer layer, an absorber layer, a back electrode layer, and a substrate, and the linear structure is composed of a metal grid wire located on the upper surface of the front electrode layer.

[0035] In some embodiments, the metal grid wires include a metal grid wire G1 perpendicular to the P1, P2, and P3 wires, and a metal grid wire G2 parallel to the P2 wire and above the P2 wire.

[0036] In some embodiments, the method for producing the metal grid wire G1 is as follows: Step G1(1) is to acquire pre-set positions, which are designated as a first lateral pre-set position and a second lateral pre-set position, on both sides of the metal grid line G1 on the surface of the front electrode, Step G1(2) involves generating a plurality of protrusions at intervals along the lateral longitudinal direction at the first lateral pre-set position and the second lateral pre-set position, respectively, to form a first protruding line and a second protruding line, The method includes step G1(3), which involves applying and depositing a liquid metal grid wire material between the first protruding wire and the second protruding wire to obtain the metal grid wire G1 sealed between the first protruding wire and the second protruding wire, The method for producing the aforementioned metal grid wire G2 is as follows: Step G2(1) is to obtain the position on the surface of the front electrode, which is the position of the P2 line on the side closer to the P3 line, and which is designated as the third lateral position. Step G2(2) involves generating a plurality of protrusions at intervals along the lateral longitudinal direction at the third lateral position to form a third protruding line, The method includes step G2(3), which involves coating and depositing a liquid metal grid wire material within the P2 wire to obtain a metal grid wire G2 in which the side of the metal grid wire G2 closest to the P3 wire is sealed by the third protruding wire.

[0037] In some embodiments, the material of the metal grid wire includes, but is not limited to, metal ink and dielectric ink.

[0038] In a fourth embodiment, a method is provided for optimizing the aspect ratio of a metal grid wire based on an improved surface structure of a front electrode, the method comprising controlling and optimizing the aspect ratio of the metal grid wire by controlling the deposition width and thickness of the metal grid wire by controlling the distance between a first protrusion and a second protrusion, the height of the protrusion and the amount of metal grid wire material.

[0039] In a fifth embodiment, a method for fabricating a thin-film solar cell is provided based on a method for fabricating a metal grid wire, the method being: The steps include sequentially forming the substrate, back electrode layer, absorber layer, buffer layer, and front electrode layer of a thin-film solar cell, or sequentially forming the substrate, front electrode layer, buffer layer, absorber layer, and back electrode layer of a thin-film solar cell, The steps include: after forming the back electrode layer, placing the P1 line on the back electrode layer; after forming the buffer layer, placing the P2 line on the absorber layer and the buffer layer; after forming the front electrode layer, placing the P3 line on the front electrode layer; and using the P1 line, the P2 line, and the P3 line to partition and connect the large-area thin-film solar cell in series; The method includes the step of forming metal grid wires G1 and G2, respectively, on the surface of the front electrode layer that is far from the buffer layer, based on a method for manufacturing metal grid wires. [Brief explanation of the drawing]

[0040] [Figure 1] This is a schematic cross-sectional view of a thin-film solar cell. [Figure 2] This is a schematic diagram of the cell width, active region, and dead region of a thin-film solar cell. [Figure 3] This is a schematic cross-sectional view of a thin-film solar cell having a metal grid wire G1. [Figure 4] This is a schematic diagram of the grid width and grid pitch of a thin-film solar cell having metal grid wires G1. [Figure 5] This is a plan view of three interconnected cells, each equipped with a thin-film photovoltaic module having a metal grid wire G1. [Figure 6] This is a schematic diagram of the current direction within the metal grid wire G1. [Figure 7] This is a schematic diagram illustrating a grid deposition process on a substrate using thermal evaporation and a mask. [Figure 8] This diagram shows the "coffee ring" effect that occurs in inkjet printing technology. [Figure 9] This is a schematic diagram illustrating the formation of protrusions using a pulsed laser during the fabrication of a metal grid wire G1. [Figure 10]These are grayscale images taken with a confocal microscope when two protruding lines formed on the upper part of the front electrode during the fabrication of the metal grid wire G1. Figure 10A is a 2D image, and Figure 10B is a 3D image. [Figure 11] This is a cross-sectional image of two protruding lines formed on the upper part of the front electrode during the fabrication of the metal grid wire G1. [Figure 12] This is a schematic diagram illustrating the containment effect of a liquid-type metal grid wire material by two protrusions on the first and second protruding lines located inside. [Figure 13] This is a schematic diagram of the possible positional distribution of protrusions on the first and second protruding lines. [Figure 14] This is a cross-sectional view of a layer stack of thin-film solar cells having two metal grid lines G1 and G2. [Figure 15] This is a plan view of a thin-film solar cell having two metal grid lines G1 and G2. [Figure 16] This is a plan view of three interconnected cells, each comprising a thin-film photovoltaic module with two metal grid lines G1 and G2. [Figure 17] This is a schematic diagram of the current direction in two metal grid wires G1 and G2. [Figure 18] This is a schematic diagram illustrating the generation of a third projection using a pulsed laser. [Figure 19] Figure 19A is a pseudo-3D grayscale image of the third protruding line captured with a confocal microscope, where the metal grid line G2 can be contained on one side. Figure 19B is a pseudo-3D grayscale image of the groove created by ablation of the buffer layer and front electrode due to excessively high laser power applied while forming the above protrusion. [Figure 20] This is a pseudo-2D grayscale image of the third protruding line. [Figure 21] This is a cross-sectional image of the projection of the third protruding line. [Figure 22]Figure 22A is a schematic diagram showing the deposition of metal grid wire G2 material on line P2 after the formation of the third protruding line, Figure 22B is a schematic diagram showing one side of metal grid wire G2 near P3 sealed after the deposition of metal grid wire G2 material. [Figure 23] This is a schematic diagram showing the positional distribution of protrusions on the third projection line. [Modes for carrying out the invention]

[0041] This application applies to a process for fabricating a thin-film photovoltaic module, which is composed of a layer stack. For example, a thin-film photovoltaic module includes, in order from bottom to top, a substrate, a back electrode layer, an absorber layer, a buffer layer, and a front electrode layer. Considering that in a process for fabricating a thin-film photovoltaic module, it is necessary to fabricate a narrow linear structure (e.g., a metal grid wire) on the upper surface of one layer, and that the width, thickness, and position of this narrow linear structure must be controlled and limited, this application provides a method for fabricating a narrow linear structure on the upper surface of a target layer of a layer stack containing at least two layers, applicable to a process for fabricating a thin-film photovoltaic module. The method for fabricating a linear structure is: A step of obtaining pre-set positions, which are designated as a first lateral position and a second lateral position, on both sides of the linear structure on the upper surface of the target layer, The steps include: forming a protruding line at at least one of the first and second lateral positions on the upper surface of the target layer by generating a plurality of protrusions spaced apart along the lateral longitudinal direction; The method includes the step of applying and depositing a liquid linear structural material on one side of the protruding line to obtain a linear structure enclosed by one side of the protruding line.

[0042] In the embodiments of the present application, multiple protrusions are formed on the side of the linear structure to form a protruding line, and the lateral position of the linear structure is contained by the protruding line. When the first protruding line is formed at the first lateral position, when the liquid-type linear structure material is applied to the side of the first protruding line closer to the second lateral position, the first side of the linear structure obtained by deposition is contained in the region where the first protruding line is close to the second lateral position, and the first side of the linear structure obtained by deposition does not reach the region where the first protruding line is far from the second side. In other words, the protruding line limits the lateral position of the deposited liquid-type linear structure material. Furthermore, when the first and second protruding lines are formed at the first and second lateral positions, respectively, a linear structure in which two lateral positions are contained, i.e., a linear structure contained between the first and second protruding lines, can be obtained by applying the liquid-type linear structure material between the first and second protruding lines. If a protruding line (referred to as the third protruding line) is formed at one of the first and second lateral positions, a liquid linear structural material is applied to one side of the third protruding line, and one side of the linear structure obtained by deposition is contained within that side of the third protruding line without reaching the other side of the third protruding line.

[0043] Furthermore, if a plurality of protrusions are formed at intervals along the lateral longitudinal direction at the first and second lateral positions on the upper surface of the target layer, respectively, forming a first and second protruding line, then by applying and depositing the liquid-type linear structural material between the first and second protruding lines, a linear structure enclosed between the first and second protruding lines, i.e., a linear structure enclosed on both sides, can be obtained. If, at one of the first and second lateral positions on the upper surface of the target layer, a plurality of protrusions are formed at intervals along the lateral longitudinal direction to form a third protruding line, a linear structure enclosed on one side of the third protruding line, i.e., a linear structure enclosed on one side, is obtained by applying and depositing a liquid linear structural material on one side of the third protruding line.

[0044] In the embodiments of the present application, the linear structure may be enclosed on one or both sides by a protruding line formed by a plurality of closely adjacent protrusions.

[0045] Furthermore, in the method of creating a narrow linear structure on the upper surface of the target layer of a layer stack, considering the difficulty in controlling the surface tension, wettability, and other properties of the linear structure material, as well as the shape of the lines formed by the deposited linear structure material, when creating a linear structure using a liquid-type linear structure during the mass production of thin-film solar cells, multiple upward protrusions are generated on the upper surface of the target layer of the thin-film solar cell. By surrounding the edge of the deposited area of ​​the linear structure material with multiple densely distributed protrusions, the deposited area of ​​the linear structure material is contained, thereby achieving control of the linear shape of the linear structure. By adjusting the position of the protrusions, i.e., changing the position of the protruding lines, the lateral position of at least one of the linear structures can be restricted, and by restricting the lateral positions of both the linear structures, the line width of the linear structure can be changed. Of course, if the amount of linear structure material is fixed, reducing the line width of the linear structure will also increase the thickness of the lines of the linear structure. Alternatively, if the line width of the linear structure is not changed, the thickness of the lines of the linear structure can also be increased by increasing the height of the protrusions, for example, by increasing the amount of linear structure material applied.

[0046] Furthermore, if, after multiple upward protrusions are formed on the upper surface of the target layer of a thin-film solar cell, the distance between two adjacent protrusions (protrusion A and protrusion B) is very small, it will not be possible to accommodate the linear structural material between the two adjacent protrusions (protrusion A and protrusion B). Therefore, by connecting multiple protrusions A and B (where the distance between multiple protrusions A and B is very small) to form a protruding line, and by restricting the linear structural material so that it does not overflow from the position of the protruding line, it is possible to restrict the position of at least one side of the linear structure.

[0047] If the distance between two adjacent protrusions (protrusion C and protrusion D) is large, and a "valley" is formed between protrusion C and protrusion D, the linear structural material can be accommodated between the two adjacent protrusions (protrusion C and protrusion D). Based on this, by ensuring that the heights of protrusions C and D are sufficiently high, the width of the linear structural material deposited between protrusions C and protrusion D can be freely controlled by adjusting the distance between protrusions C and protrusion D. Therefore, by changing the distance between the protrusions, the width of the linear structure can be changed.

[0048] Multiple protrusions A and B (with very small distances between them) are connected to form a protruding line, which can be used to limit the overflow of metal grid wire material from the protruding line. When multiple protruding lines are used in combination, the areas between adjacent or nearby protruding lines can accommodate linear structural material.

[0049] The linear structure may be a straight line or another shape, and by adjusting the shape of the protruding lines, linear structures of different shapes can be formed by deposition. In the embodiment of this application, a linear structure that is a straight line is given as an example for illustrative purposes.

[0050] Specifically, the method for enclosing a linear structure on both sides or one side in the embodiments of the present invention includes the following steps:

[0051] (Step 1) Determine the pre-set position of the linear structure on the upper surface of the target layer, and determine the pre-set positions on both sides of the linear structure on the upper surface of the target layer, which are to be the first lateral pre-set position and the second lateral pre-set position, by combining them with the pre-set width of the linear structure. This pre-set width is a preferred value that satisfies the width of the linear structure determined before the linear structure is manufactured, and therefore the distance between the first lateral pre-set position and the second lateral pre-set position is the preferred width of the linear structure.

[0052] (Step 2) If it is necessary to restrict two lateral positions of the linear structure, a plurality of protrusions are generated at intervals along the lateral longitudinal direction at the first lateral pre-set position and the second lateral pre-set position to form a first protruding line and a second protruding line, respectively, and the linear structure is applied between the first protruding line and the second protruding line, and the region between the first protruding line and the second protruding line is the region in which the linear structure is located.

[0053] (Step 3) If it is necessary to restrict one lateral position of the linear structure, a third protruding line is formed by forming a plurality of projections spaced apart along the lateral longitudinal direction at one of the first lateral pre-set positions and the second lateral pre-set position, and a liquid linear structure material is applied and deposited on one side of the third protruding line to obtain a linear structure enclosed on that side of the third protruding line.

[0054] Furthermore, for the first, second, and third protruding lines in steps 1 to 3 described above, the spacing between two adjacent protrusions on the same protruding line is sufficiently small to prevent the linear structural material from overflowing from one side of the protruding line to the other side during deposition.

[0055] Furthermore, in both the double-sided containment achieved by the first and second protruding lines, and the single-sided containment achieved by the third protruding line, it is required that when the linear structural material is applied to one side of the protruding line, the linear structural material does not overflow to the other side of the protruding line after it has been deposited. Specifically, when the linear structure is contained on both sides by the first and second protruding lines, the spacing between two adjacent protrusions on the first protruding line and the spacing between two adjacent protrusions on the second protruding line are sufficiently small so as to prevent the linear structural material from overflowing from the area between the first and second protruding lines during deposition. When the linear structure is contained on one side by the third protruding line, the spacing between two adjacent protrusions on the third protruding line is sufficiently small so as to prevent the linear structural material from overflowing from one side of the third protruding line to the other side during deposition.

[0056] In alternative embodiments, the distance between two adjacent protrusions on the same protrusion is less than 10 micrometers. That is, the distance between two adjacent protrusions on the first protrusion is less than 10 micrometers, and the distance between two adjacent protrusions on the second protrusion is less than 10 micrometers. In some embodiments, the distance between two adjacent protrusions on the same protrusion is several micrometers.

[0057] In one embodiment, when the linear structure is contained on both sides, the projections of the first protruding line and the projections of the second protruding line are asymmetrical along the midline between the first protruding line and the second protruding line.

[0058] In another embodiment, when the linear structure is contained on both sides, the projections of the first protruding line and the projections of the second protruding line are symmetrical along the midline between the first and second protruding lines.

[0059] Specifically, referring to Figure 13, when the linear structure is contained on both sides, in one embodiment, the distribution spacing between the protrusions of the first protrusion corresponds to the distribution spacing between the protrusions of the second protrusion, i.e., the distribution spacing between the protrusions of the first protrusion is related to the distribution spacing between the protrusions of the second protrusion. In another embodiment, the distribution spacing between the protrusions of the first protrusion does not have to correspond to the distribution spacing between the protrusions of the second protrusion, i.e., the distribution spacing between the protrusions of the first protrusion is not related to the distribution spacing between the protrusions of the second protrusion. There is a center line between the first and second protrusions, and (as shown in Figure 13A) one protrusion on the first protrusion and one protrusion on the second protrusion may be symmetrical with respect to the center line. Of course, one protrusion on the first protrusion and one protrusion on the second protrusion may be asymmetrical with respect to the center line (as shown in Figures 13B and 13C).

[0060] Furthermore, in one embodiment, the spacing between two adjacent protrusions on the same projection line is uniform. That is, when the linear structure is contained on both sides, (as shown in Figures 13A and 13B) the spacing between two adjacent protrusions on the first projection is uniform, and / or the spacing between two adjacent protrusions on the second projection is uniform. As shown in Figure 23A, when the linear structure is contained on one side, the spacing between two adjacent protrusions on the third projection line is uniform.

[0061] In another embodiment, the spacing between two adjacent protrusions on the same projection line is uneven. That is, when the linear structure is contained on both sides, the spacing between two adjacent protrusions on the first protrusion is uneven (as shown in Figure 13C), and / or the spacing between two adjacent protrusions on the second protrusion is uneven. When the linear structure is contained on one side, as shown in Figure 23B, the spacing between two adjacent protrusions on the third projection line is uneven.

[0062] In other words, the distribution spacing between protrusions on different protrusions does not affect each other, as long as the spacing between two adjacent protrusions on the same protrusion is small enough to prevent the linear structural material from overflowing from one side of the protrusion to the other side during deposition.

[0063] There are also requirements regarding the height of the protrusions to prevent the linear structural material from overflowing from one side of the protrusion to the other side during deposition, i.e., to prevent the linear structural material from overflowing from one side of the protrusion to the other side during deposition. In one embodiment, the height of the protrusions is required to be large enough to prevent the material for forming the linear structure from overflowing from the protrusions during the formation of the linear structure. In another embodiment, the required height of the protrusions is determined based on the characteristic parameters of the linear structural material. For example, to prevent the linear structural material from overflowing from the protrusions, the required height of the protrusions is determined based on the amount, viscosity, and surface tension of the linear structural material. In another embodiment, the height of the protrusions is required to be greater than 100 nanometers, and generally speaking, the height of the formed protrusions is usually in the range of several hundred nanometers to micrometers.

[0064] Next, we will explain how to generate the protrusions.

[0065] A method for generating protrusions on a first protrusion, a second protrusion, and a third protrusion includes irradiating a pulsed laser from above a target layer, irradiating the upper surface of the target layer with the pulsed laser to satisfy pre-set process parameters, such that the pulsed laser passes through the target layer and reaches the interface of two adjacent layers among a plurality of layers below the target layer, thereby melting and evaporating a portion of the layer material at the interface of the two adjacent layers to form an upward protrusion.

[0066] As shown in Figures 9 and 18, the pulsed laser is irradiated onto the upper surface of the target layer, passes through the target layer, and reaches the interface between two of the multiple layers below the target layer. As a result, a portion of the layer material melts and evaporates at the interface between two adjacent layers, forming an upward protrusion, thereby achieving the formation of a protrusion on the upper surface of the target layer.

[0067] Furthermore, the pre-configured process parameters of the pulsed laser must be set rationally, including the pulsed laser's wavelength, power, irradiation time, irradiation frequency, velocity, and beam diameter. The following example illustrates the adjustment of the pulsed laser's wavelength and power.

[0068] Because the wavelength of the pulsed laser is greater than the optical band gap of the target layer and smaller than the optical band gap of the material in at least one of the multiple layers beneath the target layer, the pulsed laser can pass through the target layer and stop in any of the layers beneath it. The pulsed laser is not absorbed in the layer it passes through, but is absorbed at the interface where it stops, causing a portion of the material at that interface to melt and evaporate, forming an upward protrusion.

[0069] Regarding the pulsed laser power, it is necessary to adjust the pulsed laser power in order to form upward protrusions on the upper surface of the target layer. If the pulsed laser power is too low, it will only cause localized heating and will not form protrusions. If the power is too high, the layer through which the pulsed laser passes will be completely ablated, forming holes instead of upward protrusions.

[0070] Specifically, the laser power of a pulsed laser is adjusted according to the thickness of the target layer and the characteristic parameters of the target layer material. For example, the laser power of a pulsed laser is determined according to the hardness, stiffness, tension, adhesion, and other characteristic parameters of the material of the front electrode layer.

[0071] In this application, the method for applying the liquid linear structural material includes, but is not limited to, inkjet printing, aerosol spraying, screen printing, and dispensing.

[0072] This invention provides a method for fabricating a narrow linear structure on the upper surface of a target layer of a layer stack, applicable to the process of fabricating thin-film photovoltaic modules. The method is applicable, for example, to the fabrication of thin-film photovoltaic modules having a substrate structure and a surface plate structure, and to the fabrication of CIGS, CdTe, and perovskite type thin-film photovoltaic modules.

[0073] The method for creating a narrow linear structure on the upper surface of a target layer of a layer stack, as described in this application, is also applicable to single-pass and / or multi-pass coating of liquid linear structural materials.

[0074] Below, for illustrative purposes, a linear structure composed of metal grid wires is given as an example. In this application, it is necessary to create a metal grid wire G1. In order to optimize the aspect ratio of the metal grid wire G1 by controlling and optimizing the shape (including width and thickness parameters) of the metal grid wire G1 on the surface of the front electrode, it is necessary to first generate two protruding lines at two lateral positions of the metal grid wire G1 on the surface of the front electrode, and then deposit the metal grid wire material within the region between the two protruding lines to form the metal grid wire G1. In this application, it is necessary to form a metal grid wire G2, and in order to control and contain the side of the metal grid wire G2 closer to the P3 line so that it is not covered or divided by the P3 line, it is necessary to limit the position of the side of the metal grid wire G2 closer to the P3 line so that it does not reach the P3 line by forming a third protruding line on the surface of the front electrode on the side of the P2 line closer to the P3 line so that the side of the deposited metal grid wire G2 material closer to the P3 line does not overflow from the third protruding line.

[0075] Specifically, a method is provided for fabricating a metal grid line based on an improved surface structure of a front electrode, based on a method for fabricating a narrow linear structure on the upper surface of a target layer of a layer stack, wherein the target layer is the front electrode layer, and the multiple layers below the target layer include a buffer layer, an absorber layer, a back electrode layer, and a substrate, and the linear structure consists of a metal grid line located on the upper surface of the front electrode layer. The metal grid line includes a metal grid line G1 perpendicular to the P1, P2, and P3 lines, and a metal grid line G2 parallel to the P2 line and located above the P2 line. In this embodiment, it is necessary to control and optimize the width and thickness of the metal grid line G1 in order to optimize its aspect ratio, i.e., it is necessary to limit the positions of both sides of the metal grid line G1. In this embodiment, it is necessary to limit the position of one side of the metal grid line G2 so that the side of the metal grid line G2 closer to the P3 line does not reach the P3 line, i.e., it does not cover the P3 line or is not divided by the P3 line. Specifically, the method for fabricating the metal grid wire G1 is as follows: Step G1(1) is to acquire pre-set positions, which are designated as a first lateral pre-set position and a second lateral pre-set position, on both sides of the metal grid line G1 on the surface of the front electrode, Step G1(2) involves generating a plurality of protrusions at intervals along the lateral longitudinal direction at the first lateral pre-set position and the second lateral pre-set position, respectively, to form a first protruding line and a second protruding line, The method includes step G1(3), which involves applying and depositing a liquid metal grid wire material between the first protruding wire and the second protruding wire to obtain the metal grid wire G1 sealed between the first protruding wire and the second protruding wire, The method for fabricating metal grid wire G2 is: Step G2(1) is to obtain the position on the surface of the front electrode, which is the position of the P2 line on the side closer to the P3 line, and which is designated as the third lateral position. Step G2(2) involves generating a plurality of protrusions at intervals along the lateral longitudinal direction at the third lateral position to form a third protruding line, The method includes step G2(3), which involves coating and depositing a liquid metal grid wire material within the P2 wire to obtain a metal grid wire G2 in which the side of the metal grid wire G2 closest to the P3 wire is sealed by the third protruding wire.

[0076] The width and thickness of the metal grid wire G1 are controlled via steps G1(1), G1(2), and G1(3) described above. Specifically, in step G1(1), a preset position of the metal grid wire G1 on the surface of the front electrode is determined, and the preset positions recorded as a first lateral preset position and a second lateral preset position on both sides of the metal grid wire G1 on the surface of the front electrode are combined with the preset width of the metal grid wire G1 to determine the preset width. The preset width is a preferred value for the width of the metal grid wire that satisfies the aspect ratio condition of the metal grid wire determined before the metal grid wire is manufactured. Therefore, the distance between the first lateral preset position and the second lateral preset position is the preferred width of the metal grid wire. In step G1(3), the method for applying the metal grid wire material may be inkjet printing, aerosol spraying, screen printing, dispensing, etc., with inkjet printing being a preferred technique.

[0077] In the process of fabricating metal grid wires G1 and G2, the method for generating protrusions is as follows: By irradiating the front electrode layer with a pulsed laser at a surface far from the buffer layer using pre-set process parameters, at least the front electrode layer protrudes upward at the position where the laser was irradiated. Specifically, in this application, by irradiating the surface of the front electrode layer with a pulsed laser, the pulsed laser passes through the front electrode layer from above the thin film solar cell until one of the layers below, i.e., the buffer layer, absorber layer, back electrode layer, and substrate, absorbs the laser irradiation. As the pulsed laser attempts to pass through the interface where it has stopped, a portion of the layer material melts and evaporates, thus forming an upward protrusion at the position where the pulsed laser was irradiated. The pre-set process parameters of the pulsed laser must be reasonably set and include the wavelength, power, irradiation time, irradiation frequency, velocity, and beam diameter of the pulsed laser. For example, in the embodiments of the present application, the wavelength of the pulsed laser irradiated onto the upper surface of the front electrode layer must be greater than the optical bandcap of the front electrode layer so that the pulsed laser can pass through the front electrode layer, but the wavelength of the pulsed laser is smaller than the optical bandgap of at least one of the buffer layer, absorber layer, and back electrode layer. For example, if the wavelength of the pulsed laser is greater than the optical bandgap of the front electrode layer and buffer layer but smaller than the optical bandgap of the absorber layer, the laser will pass through the front electrode layer and buffer layer and be absorbed when it reaches the interface between the buffer layer and the absorber layer, so that a portion of the material at the interface between the absorber layer and the buffer layer melts and evaporates, creating an upward protrusion in the layer stack toward the front electrode.

[0078] Regarding the power of the pulsed laser, it is necessary to determine the power of the pulsed laser in order to form upward protrusions on the surface of the front electrode layer. If the pulsed laser power is too low, it will only cause localized heating and will not be able to form protrusions. If the power is too high, the buffer layer and the front electrode layer will be completely ablated, for example, as is done when using a laser P3 line, which will significantly reduce the area of ​​interconnection between the metal grid line and the front electrode, thus widening the line and increasing the series resistance (up to the thickness of the front electrode layer). Specifically, the laser power of the pulsed laser is determined according to the thickness of the front electrode layer and the characteristic parameters of the material of the front electrode layer. For example, the laser power of the pulsed laser is determined according to the hardness, stiffness, tension, adhesion and other characteristic parameters of the material of the front electrode layer.

[0079] For example, in the process of fabricating metal grid wires G1 and G2, the process parameters of the pulsed laser used to form the protrusions may be as follows: In the case of a CIGS with an AZO (front electrode) thickness of 750 nm and a ZnOS (buffer) thickness of 65 nm, the laser power window is between 150 mW and 250 mW, the wavelength is 1064 nm, the laser pulse width is 15 ps, the repetition rate is 500 kHz, the process speed is 10800 mm / min, and the beam diameter is approximately 20 μm.

[0080] Figure 10 shows microscopic images of the first and second protrusions (with a distance of 20 micrometers between them) in the process of fabricating the metal grid wire G1. Figure 11 shows cross-sectional images of the first and second protrusions (with a distance of 10 micrometers between them). Since the width of a single protrusion on the first and second protrusions is within the range of approximately 10 micrometers, the distance between the first and second protrusions must be greater than 10 micrometers. This allows the metal grid wire G1 to be formed between the first and second protrusions by accommodating the material for the metal grid wire G1 between them.

[0081] Referring to Figure 12, when the material of the metal grid wire G1 is contained between the two protrusions, the material of the metal grid wire G1 fills the space between the two protrusions, and the coffee ring effect shown in Figure 8 is also avoided.

[0082] Figure 18 shows a schematic diagram of the process of creating a protrusion of a third protrusion using a pulsed laser in the process of fabricating a metal grid wire G2. Figure 19 shows a pseudo-3D grayscale image of the third protrusion in the process of fabricating the metal grid wire G2, and Figure 19B shows a pseudo-3D grayscale image of one-sided containment of the metal grid wire G2 by the formed third protrusion, and Figure 19B is a pseudo-3D grayscale image showing the case where grooves are created due to abrasion of the buffer layer and front electrode because the laser power is too high. Figure 20 shows a pseudo-2D grayscale image of the third protrusion for achieving one-sided containment, and Figure 21 is a cross-sectional image of the protrusion of the third protrusion showing the maximum height, average height and width of the protrusion of the third protrusion. Figure 22 shows a schematic diagram of depositing the material for the metal grid wire G2 on the P2 line after the formation of the third protruding line, Figure 22A shows a schematic diagram of coating the material for the metal grid wire G2 on the P2 line after the formation of the third protruding line, and Figure 22B shows a schematic diagram of one side near P3 being sealed after the deposit of the material for the metal grid wire G2.

[0083] The material for the metal grid wire includes, but is not limited to, metal ink and dielectric ink.

[0084] Based on the above method for fabricating a metal grid wire based on an improved surface structure of a front electrode, the present invention further provides a method for optimizing the aspect ratio of a metal grid wire, the method comprising the steps of controlling and optimizing the aspect ratio of a metal grid wire by controlling the deposition width and thickness of the metal grid wire by controlling the distance between a first protrusion and a second protrusion, the height of the protrusion and the amount of metal grid wire material.

[0085] A method for fabricating a thin-film solar cell is provided based on a method for fabricating a metal grid wire based on an improved surface structure of a front electrode, the method comprising the following steps:

[0086] The process for manufacturing a photovoltaic module involves, when using a substrate approach, sequentially forming the substrate, back electrode layer, absorber layer, buffer layer, and front electrode layer of the thin-film solar cell, and when using a front-plate approach, sequentially forming the substrate, front electrode layer, buffer layer, absorber layer, and back electrode layer of the thin-film solar cell. This process includes the generation of P1, P2, and P3 lines. After forming the back electrode layer, the P1 line is placed on the back electrode layer; after forming the absorber layer and buffer layer, the P2 line is placed on the absorber layer and buffer layer; after forming the front electrode layer, the P3 line is placed on the front electrode layer. Together, the P1, P2, and P3 lines are used to partition and connect the large-area thin-film solar cell.

[0087] Process for fabricating metal grid wires G1 and G2: Based on the above method for fabricating metal grid wires, metal grid wires G1 and G2 are formed on the surface of the front electrode layer that is far from the buffer layer.

[0088] This application is not limited to the specific embodiments described above, and various modifications made by those skilled in the art without creative effort from the above idea are also covered by this application. [Explanation of Symbols]

[0089] 1 Front electrode layer 2 buffer layers 3. Absorbent layer 4 Back electrode layer 5 circuit boards 6 Metal grid wire G1

Claims

1. Applicable to a process for manufacturing a thin-film photovoltaic module, It includes a front electrode layer, a buffer layer below the front electrode layer, an absorber layer below the buffer layer, a back electrode layer below the absorber layer, and a substrate below the back electrode layer. A method for creating a metal grid line on the upper surface of the front electrode layer of a layer stack, The aforementioned metal grid wire is A metal grid wire G1 perpendicular to the P1, P2, and P3 wires, A metal grid wire G2 that is parallel to the aforementioned P2 line and located above the aforementioned P2 line, Includes, The method for producing the aforementioned metal grid wire G1 is as follows: Step G1(1) is to acquire pre-set positions, which are to be a first lateral pre-set position and a second lateral pre-set position, on both sides of the metal grid line G1 on the surface of the front electrode layer, Step G1(2) involves generating a plurality of protrusions at intervals along the lateral longitudinal direction at the first lateral pre-set position and the second lateral pre-set position, respectively, to form a first protruding line and a second protruding line, Step G1 (3) involves applying and depositing the liquid-type metal grid wire material between the first protruding wire and the second protruding wire to obtain the metal grid wire G1 sealed between the first protruding wire and the second protruding wire, Includes, The method for producing the aforementioned metal grid wire G2 is as follows: Step G2(1) is to obtain the position on the surface of the front electrode layer that is on the side of the P2 line closest to the P3 line and is designated as the third lateral position, Step G2(2) involves generating a plurality of protrusions at intervals along the lateral longitudinal direction at the third lateral position to form a third protruding line, Step G2(3) involves applying and depositing the liquid-type metal grid wire material into the P2 wire to obtain a metal grid wire G2 in which the side of the metal grid wire G2 closest to the P3 wire is sealed by the third protruding wire, Includes, The method for generating the protrusions includes the step of irradiating the upper surface of the front electrode layer with a pulsed laser from above the front electrode layer, using pre-set process parameters, so that the pulses of the pulsed laser pass through the front electrode layer and reach the interface between the absorber layer and the buffer layer, thereby melting and evaporating a portion of the layer material at the interface to form upward protrusions. A method for fabricating metal grid wires.

2. The spacing between two adjacent protrusions on the same protrusion is small enough to prevent the material of the metal grid wire from overflowing from one side of the protrusion to the other side during deposition. A method for producing a metal grid wire according to claim 1.

3. The distance between two adjacent protrusions on the same protrusion is less than 10 micrometers. A method for producing a metal grid wire according to claim 2.

4. When the metal grid wire is enclosed on both sides, the projection of the first protruding wire and the projection of the second protruding wire are asymmetrical along the center line between the first protruding wire and the second protruding wire. A method for producing a metal grid wire according to claim 1.

5. When the metal grid wire is enclosed on both sides, the projection of the first projection and the projection of the second projection are symmetrical along the center line between the first projection and the second projection. A method for producing a metal grid wire according to claim 1.

6. The spacing between two adjacent protrusions on the same projection line is uniform. A method for producing a metal grid wire according to claim 1.

7. The spacing between two adjacent protrusions on the same projection line is uneven. A method for producing a metal grid wire according to claim 1.

8. The height of the protrusion is sufficiently large to prevent the material for forming the metal grid from overflowing from the protrusion during the formation of the metal grid. A method for producing a metal grid wire according to claim 1.

9. The height of the protrusion is determined based on the characteristic parameters of the material used to form the metal grid wire. A method for producing a metal grid wire according to claim 8.

10. The characteristic parameters of the material for forming the metal grid wire include at least the amount, viscosity, and surface tension of the material. A method for producing a metal grid wire according to claim 9.

11. The height of the aforementioned protrusion is greater than 100 nanometers. A method for producing a metal grid wire according to claim 9.

12. The pre-set process parameters of the pulsed laser satisfy the condition that the wavelength of the pulsed laser is greater than the wavelength corresponding to the optical band gap of the front electrode layer, but less than the wavelength corresponding to the optical band gap of at least one of the layers below the front electrode layer. A method for producing a metal grid wire according to claim 1.

13. Of the pre-set process parameters of the pulsed laser, the laser power of the pulsed laser is determined based on the thickness of the front electrode layer and the characteristic parameters of the material of the front electrode layer. A method for producing a metal grid wire according to claim 1.

14. The characteristic parameters of the material of the front electrode layer include at least the hardness, rigidity, tension, and adhesiveness of the material of the front electrode layer. A method for producing a metal grid wire according to claim 13.

15. The method for applying the liquid-type metal grid wire material includes, but is not limited to, inkjet printing, aerosol spraying, screen printing, and dispensing. A method for producing a metal grid wire according to claim 1.

16. Using the method for producing a metal grid wire as described in claim 1, A single-pass and / or multi-pass coating method for liquid-type metal grid wire material.

17. The material for the metal grid wire includes, but is not limited to, metal ink and dielectric ink. A method for producing a metal grid wire according to claim 1.

18. A method for optimizing the aspect ratio of a metal grid wire based on the method for producing a metal grid wire according to Claim 1, comprising the steps of controlling and optimizing the aspect ratio of the metal grid wire by controlling the deposition width and thickness of the metal grid wire by controlling the distance between the first protruding line and the second protruding line, the height of the protrusions and the amount of material for the metal grid wire. A method for optimizing the aspect ratio of metal grid lines.

19. A method for manufacturing a thin-film solar cell based on the method for manufacturing a metal grid wire as described in Claim 1, The steps of sequentially forming the substrate, back electrode layer, absorber layer, buffer layer and front electrode layer of a thin-film solar cell, or sequentially forming the substrate, front electrode layer, buffer layer, absorber layer and back electrode layer of a thin-film solar cell, The steps include: after forming the back electrode layer, placing the P1 line on the back electrode layer; after forming the buffer layer, placing the P2 line on the absorber layer and the buffer layer; after forming the front electrode layer, placing the P3 line on the front electrode layer; and using the P1 line, the P2 line, and the P3 line to partition and connect in series the large-area thin-film solar cell; A step of forming the metal grid wire G1 and the metal grid wire G2 on the surface of the front electrode layer that is far from the buffer layer, based on the method for producing a metal grid wire according to claim 1, A method for fabricating thin-film solar cells containing [a specific substance].

20. A product manufactured by the method of Claim 19 Thin-film photovoltaic module.

21. A part of the building envelope, which is a window, facade, or roof member, comprising the solar module described in Claim 20.

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