JP-7855804-B2 - Method for fabricating a metal grid on the upper surface of a target layer in a layer stack and its application

JP7855804B2JP 7855804 B2JP7855804 B2JP 7855804B2JP-7855804-B2

Inventors

シェンイレイ
シュテルツェルマルコ

Assignees

中建材玻璃新材料研究院集団有限公司

Dates

Publication Date: 20260508
Application Date: 20231124

Claims (20)

Applied to the process of fabricating thin-film photovoltaic modules , 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.
The method for producing a metal grid wire according to claim 1, wherein 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 of the protrusion during deposition.
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 .
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 .
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 .
A method for producing a metal grid wire according to claim 1, wherein the spacing between two adjacent protrusions on the same protruding line is uniform.
A method for producing a metal grid wire according to claim 1, wherein the spacing between two adjacent protrusions on the same protruding line is non-uniform.
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 , the method for producing a metal grid according to claim 1.
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 .
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 .
The height of the aforementioned protrusion is greater than 100 nanometers. A method for producing a metal grid wire according to claim 9 .
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 .
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 .
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 .
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. The method for producing a metal grid wire according to claim 1.
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.
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 .
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 producing a thin-film solar cell based on the method for producing a metal grid wire 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].
A thin-film photovoltaic module manufactured by the method described in claim 19 .

Description

This application relates to the field of thin-film solar cell technology, and more particularly to a method for fabricating a narrow linear structure on the upper surface of a target layer of a layer stack, and its applications. Thin-film solar cells have a multilayer structure. As is well known to those skilled in the art, the layer structure of a thin-film solar cell consists, in a substrate configuration, at least, from bottom to top, of a substrate, back electrode layer, absorber layer, buffer layer, and front electrode layer, although the layers are reversed in a superstraight configuration. In the case of large-area thin-film solar cells, modules are usually designed as a series of monolithic interconnected cells to avoid high series resistance and subsequent high current loss. To achieve partitioning and series connection, lines P1, P2, and P3 are arranged on the back electrode layer, absorber layer, buffer layer, and front electrode layer, respectively (as shown in Figure 1). Specifically, the method for manufacturing a thin-film solar cell is as follows: The steps include: setting up the substrate, The steps include depositing a back electrode layer on one side of the substrate, The steps include subdividing the back electrode layer with P1 lines, The steps include sequentially depositing an absorber layer and a buffer layer on the back electrode layer, The steps include simultaneously subdividing the absorber layer and the buffer layer with P2 lines, The steps include depositing a front electrode layer on the buffer layer, The process includes the step of subdividing the front electrode layer with P3 lines. P1 and P3 insulate the back electrode from the front electrode, and P2 functions as an electrical contact between the back electrode and the front electrode, thereby connecting two adjacent batteries in series. The structural regions of P1/P2/P3 do not generate electricity and are therefore typically referred to as the "dead region" of the solar cell (as shown in Figures 1 and 3). The remaining region is referred to as the active region of the solar cell. 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. To optimize the power conversion efficiency of solar cells, a common approach is to increase the transmittance of the front electrode by reducing its thickness, 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 can be applied to the front electrode layer to improve its conductivity; this is known as the metallization process for photovoltaic production. Therefore, as shown in Figures 3, 4, and 5, the metal grid wires G1 are 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 wires G1. 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 the dead region. 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