A method and system for improving efficiency of HJT battery by punctiform opening of membrane under grid lines, and a medium
Patent Information
- Application Number
- CN202611055865.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-16
- Publication Date
- 2026-10-30
AI Technical Summary
然而，该类处理方式往往会扩大钝化膜层被破坏的范围，使硅基底表面暴露面积增加，导致局部表面复合增强、少子寿命下降以及光学和电学性能损失
在HJT电池半成品的透明导电层表面沿金属栅线预定轨迹进行离散点状激光开膜，使开膜点处透明导电层、氢化非晶硅层和a-Si硅层被去除以形成硅基底局部暴露区，同时保留点间及轨迹外侧钝化膜层，并在后续制备金属栅线时使其经由开膜点与硅基底形成局部直接接触，提升了开路电压，有效解决了现有HJT电池栅线下方全膜保留易产生界面复合而连续开膜又破坏钝化的工艺取舍下，难以兼顾开路电压提升和电池整体性能稳定的问题。
Smart Images
Figure CN123021809A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photovoltaic cell manufacturing technology, and in particular to a method, system, and dielectric for improving the efficiency of HJT cell with point-like film opening under the grid line. Background Technology
[0002] HJT cells are a type of high-efficiency photovoltaic cells with a crystalline silicon substrate as the main body and hydrogenated amorphous silicon layer, a-Si silicon layer and transparent conductive layer formed on the surface of the silicon substrate. They typically reduce silicon wafer surface recombination through hydrogenated amorphous silicon layer and a-Si silicon layer, and achieve lateral conductivity and optical transmission through transparent conductive layer. Subsequently, metal grid lines are formed on the surface of transparent conductive layer to complete the collection and output of photogenerated carriers.
[0003] In existing HJT cell fabrication processes, metal grid lines are typically formed directly on the surface of a transparent conductive layer. Beneath the grid lines, a transparent conductive layer, a hydrogenated amorphous silicon layer, and an a-Si silicon layer remain, creating a multi-layered interface structure between the metal grid lines, the transparent conductive layer, the hydrogenated amorphous silicon layer, the a-Si silicon layer, and the silicon substrate. This region is prone to interface state defects and carrier recombination, limiting the effective collection of carriers beneath the metal grid lines and affecting the cell's open-circuit voltage and conversion efficiency. To improve grid line contact performance, existing technologies employ processes such as film removal or trenching in the corresponding grid line regions, allowing the metal material to contact the underlying structure more directly, reducing contact resistance and improving charge transport. However, these methods often expand the area of passivation film damage, increasing the exposed surface area of the silicon substrate, leading to enhanced local surface recombination, decreased minority carrier lifetime, and losses in optical and electrical properties. It is evident that the existing HJT battery grid contact optimization process still faces the challenge of simultaneously improving contact performance and preserving the passivation structure, making it difficult to maintain the overall passivation effect and comprehensive output performance of the battery while reducing recombination below the grid lines.
[0004] The information disclosed in this background section is intended only to enhance the understanding of the general background of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention
[0005] This invention provides a method, system, and medium for improving the efficiency of HJT battery by point-like film opening under the grid line, which can effectively solve the problems in the background art.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for improving the efficiency of HJT battery with dotted film opening below the grid line, the method comprising: On the surface of the transparent conductive layer of the HJT battery semi-finished product, the film opening trajectory corresponding to the metal grid line is determined according to the grid line pattern of the metal grid line to be formed. The HJT battery semi-finished product includes a silicon substrate and a hydrogenated amorphous silicon layer, an a-Si silicon layer and the transparent conductive layer sequentially formed on the surface of the silicon substrate. Discrete point-like laser ablation is performed on the transparent conductive layer, the hydrogenated amorphous silicon layer and the a-Si silicon layer along the ablation trajectory to form a plurality of ablation points arranged at intervals in a predetermined region corresponding to the metal gate line. The depth of the discrete point laser ablation is controlled so that the transparent conductive layer, the hydrogenated amorphous silicon layer and the a-Si silicon layer at the ablation point are removed to expose the silicon substrate, and the silicon substrate is not damaged by lattice. The transparent conductive layer, the hydrogenated amorphous silicon layer, and the a-Si silicon layer are retained between adjacent opening points and in the region outside the opening trajectory. The metal gate line is prepared on the surface of the transparent conductive layer where the opening point is formed, so that the metal gate line covers the opening trajectory and forms local direct contact with the silicon substrate through the opening point.
[0007] Furthermore, the HJT battery semi-finished product is formed from an N-type silicon wafer through texturing, cleaning, and deposition of the hydrogenated amorphous silicon layer, the a-Si silicon layer, and the transparent conductive layer. The transparent conductive layer is a TCO transparent conductive layer, the hydrogenated amorphous silicon layer is an a-Si:H silicon layer, and the metal grid lines are silver grid lines.
[0008] Furthermore, the metal grid line includes a fine grid line, the film-opening trajectory corresponds to a predetermined trajectory of the fine grid line, and the plurality of film-opening points are arranged sequentially at intervals along the extension direction of the fine grid line.
[0009] Furthermore, the discrete point-like laser film ablation uses an ultraviolet picosecond laser to continuously ablate the transparent conductive layer, the hydrogenated amorphous silicon layer, and the a-Si silicon layer, so that the ablation points are formed into point-like local film removal areas.
[0010] Furthermore, the wavelength of the ultraviolet picosecond laser is 355nm.
[0011] Furthermore, the opening point is a circular opening point with a diameter of 45 μm and a point spacing of 200 μm between adjacent circular opening points.
[0012] Furthermore, the ultraviolet picosecond laser has a power of 70W and a processing speed of 2000mm / s, and forms the multiple opening points through a single scan.
[0013] Furthermore, the plurality of opening points constitute discrete point contact regions for carriers to enter the metal gate line. The transparent conductive layer, the hydrogenated amorphous silicon layer, and the a-Si silicon layer retained between adjacent opening points and in the region outside the opening trajectory constitute a continuous passivation region, so that the metal gate line forms multiple direct contacts with the silicon substrate through the discrete point contact regions, and the surface passivation of the silicon substrate is maintained through the continuous passivation region.
[0014] A point-like film-opening system for improving efficiency under the grid line of an HJT battery, the system comprising: The film opening trajectory determination module determines the film opening trajectory corresponding to the metal grid lines on the transparent conductive layer surface of the HJT battery semi-finished product, based on the grid line pattern of the metal grid lines to be formed. The dot-matrix laser ablation module performs discrete dot-matrix laser ablation on the transparent conductive layer, the hydrogenated amorphous silicon layer and the a-Si silicon layer along the ablation trajectory to form multiple ablation points arranged at intervals in a predetermined area corresponding to the metal gate line. The film-opening depth control and damage prevention module controls the film-opening depth of discrete point laser film opening, so that the transparent conductive layer, hydrogenated amorphous silicon layer and a-Si silicon layer at the film-opening point are removed to expose the silicon substrate, and the silicon substrate is not damaged by lattice. The film layer region retention module retains a transparent conductive layer, a hydrogenated amorphous silicon layer, and an a-Si silicon layer between adjacent film opening points and in the region outside the film opening trajectory. The gate contact forming module prepares metal gate lines on the surface of a transparent conductive layer with opening points, so that the metal gate lines cover the opening trajectory and form local direct contact with the silicon substrate through the opening points.
[0015] A computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a processor, can implement the above-described method for improving efficiency by point-like film opening under the grid line of an HJT battery.
[0016] The technical solution of this invention can achieve the following technical effects: Discrete point-like laser ablation is performed on the surface of the transparent conductive layer of the HJT battery semi-finished product along a predetermined trajectory of the metal grid lines. This removes the transparent conductive layer, hydrogenated amorphous silicon layer, and a-Si silicon layer at the ablation points to form a local exposed area of the silicon substrate. At the same time, the passivation film layer between the points and outside the trajectory is retained. During the subsequent fabrication of the metal grid lines, the passivation film layer is made to form a local direct contact with the silicon substrate through the ablation points, thereby improving the open-circuit voltage. This effectively solves the problem that existing HJT battery processes, which involve retaining the full film under the grid lines, are prone to interfacial recombination, while continuous ablation damages the passivation layer. This makes it difficult to balance improving the open-circuit voltage and maintaining the overall performance stability of the battery.
[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 A flowchart illustrating the method for improving efficiency of point-like film opening under the grid line of HJT battery; Figure 2 This is a side view of the HJT membrane structure; Figure 3 This is a top view of a dotted membrane opening. Detailed Implementation
[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0022] Example 1; like Figure 1 As shown, this application provides a method for improving efficiency by dotted film opening below the grid line of an HJT battery, the method comprising: On the surface of the transparent conductive layer of the HJT battery semi-finished product, the film opening trajectory corresponding to the metal grid line is determined according to the grid line pattern of the metal grid line to be formed. The HJT battery semi-finished product includes a silicon substrate and a hydrogenated amorphous silicon layer, an a-Si silicon layer, and a transparent conductive layer formed sequentially on the surface of the silicon substrate. Discrete point-like laser ablation is performed on the transparent conductive layer, hydrogenated amorphous silicon layer and a-Si silicon layer along the ablation trajectory to form multiple ablation points arranged at intervals in a predetermined region corresponding to the metal gate line. By controlling the depth of discrete point laser ablation, the transparent conductive layer, hydrogenated amorphous silicon layer and a-Si silicon layer at the ablation point are removed to expose the silicon substrate, and the silicon substrate is not damaged by lattice. A transparent conductive layer, a hydrogenated amorphous silicon layer, and an a-Si silicon layer are retained between adjacent opening points and in the region outside the opening trajectory. Metal gate lines are fabricated on the surface of a transparent conductive layer with opening points, so that the metal gate lines cover the opening trajectory and form local direct contact with the silicon substrate through the opening points.
[0023] Specifically, this embodiment provides a method for improving efficiency by creating a dotted film opening below the grid lines of an HJT battery. An HJT battery semi-finished product that has completed film deposition but has not yet formed metal grid lines is selected. The HJT battery semi-finished product includes a silicon substrate, a hydrogenated amorphous silicon layer and an a-Si silicon layer formed on the surface of the silicon substrate, and a transparent conductive layer formed on the surfaces of the hydrogenated amorphous silicon layer and the a-Si silicon layer. The transparent conductive layer can be a TCO transparent conductive layer, and the hydrogenated amorphous silicon layer is an a-Si:H hydrogenated amorphous silicon layer. Based on the metal grid line pattern to be formed subsequently, a film opening trajectory corresponding to the position of the metal grid line is determined on the surface of the transparent conductive layer, so that the film opening trajectory is located within a predetermined formation area of the metal grid line, and the subsequently formed metal grid line can cover the film opening trajectory. After determining the film-opening trajectory, a laser processing device is used to perform discrete point-like laser film opening along the film-opening trajectory, forming multiple film-opening points arranged at intervals within a predetermined area corresponding to the metal grid line. The film-opening points are distributed along the extension direction of the film-opening trajectory, and adjacent film-opening points are kept at intervals, so that the film-opening area only occupies a local area below the metal grid line, rather than continuously removing the film layer along the entire metal grid line. In actual processing, an ultraviolet picosecond laser device can be used to continuously perform point-by-point processing aligned with the film-opening trajectory, with the laser action position corresponding to each film-opening point, so that the transparent conductive layer, hydrogenated amorphous silicon layer, and a-Si silicon layer at each film-opening point are selectively removed. During the laser delamination process, the laser energy, scanning speed, pulse position, and dot pitch are preset and controlled to ensure that the delamination depth penetrates the transparent conductive layer, the hydrogenated amorphous silicon layer, and the a-Si silicon layer. This exposes the silicon substrate at the delamination point while preventing further ablation into the silicon substrate. After delamination, a local contact area of exposed silicon substrate is formed at the delamination point. The surface of the silicon substrate remains flat and without lattice damage. The transparent conductive layer, the hydrogenated amorphous silicon layer, and the a-Si silicon layer are still intact between adjacent delamination points and in the area outside the delamination trajectory. Thus, a film structure in which a local delamination area and a continuous film retention area coexist within the predetermined area of the metal gate line is formed. After completing the dot-matrix opening, metal grid lines are fabricated on the surface of the transparent conductive layer according to the metal grid line pattern. The metal grid lines can be formed by screen printing and sintering processes, so that the metal paste covers the opening trajectory and fills the opening points. After sintering, the metal grid lines form local direct contact with the exposed silicon substrate at the opening points, and the passivation effect between adjacent opening points is still maintained by the retained transparent conductive layer, hydrogenated amorphous silicon layer and a-Si silicon layer. Thus, multiple local direct contact channels are formed under the metal grid lines, and charge carriers can enter the metal grid lines through the opening points to complete the collection, while the unopened areas continue to maintain the passivation and light transmission effect on the silicon substrate.
[0024] The technical solution of this invention involves discrete point-like laser ablation along a predetermined trajectory of metal grid lines on the surface of the transparent conductive layer of an HJT battery semi-finished product. This removes the transparent conductive layer, hydrogenated amorphous silicon layer, and a-Si silicon layer at the ablation points to form a locally exposed area of the silicon substrate. At the same time, the passivation film layer between the points and outside the trajectory is retained. During the subsequent fabrication of the metal grid lines, this passivation film layer is made to form a local direct contact with the silicon substrate through the ablation points, thereby improving the open-circuit voltage. This effectively solves the problem that existing HJT battery processes, which involve retaining the full film below the grid lines, are prone to interfacial recombination, while continuous ablation damages the passivation layer. This makes it difficult to balance improving the open-circuit voltage and maintaining the overall performance stability of the battery.
[0025] Furthermore, such as Figure 2 As shown, the HJT battery semi-finished product is formed by texturing, cleaning, and depositing a hydrogenated amorphous silicon layer, an a-Si silicon layer, and a transparent conductive layer on an N-type silicon wafer. The transparent conductive layer is a TCO transparent conductive layer, the hydrogenated amorphous silicon layer is an a-Si:H silicon layer, and the metal grid lines are silver grid lines.
[0026] As a preferred embodiment of the above embodiments, in this embodiment, the HJT battery semi-finished product uses an N-type silicon wafer as the silicon substrate; during processing, the N-type silicon wafer is first texturized to form a textured surface structure suitable for anti-reflection and subsequent film formation on the silicon wafer surface; then the texturized N-type silicon wafer is cleaned to remove surface particles, organic residues and process contaminants, so that the silicon wafer surface meets the requirements for amorphous silicon film formation. After cleaning, a-Si silicon layers are formed on the front and back sides of the N-type silicon wafer to passivate the silicon substrate surface and reduce surface recombination. An a-Si:H hydrogenated amorphous silicon layer is formed outside the a-Si silicon layer, and a TCO transparent conductive layer is formed outside the a-Si:H hydrogenated amorphous silicon layer, giving the HJT battery semi-finished product a transparent and conductive structure. The resulting HJT battery semi-finished product includes an N-type silicon wafer, an a-Si silicon layer on the surface of the N-type silicon wafer, an a-Si:H hydrogenated amorphous silicon layer, and a TCO transparent conductive layer outside the a-Si:H hydrogenated amorphous silicon layer. In subsequent processes, silver paste is used as the metal grid line material, and silver grid lines are formed on the surface of the TCO transparent conductive layer. The formation position of the silver grid lines corresponds to the predetermined film-opening trajectory, so that the silver grid lines can cover the point-like film-opening area and form local direct contact with the exposed silicon substrate at the film-opening point. Through the above process, the N-type silicon wafer, a-Si silicon layer, a-Si:H hydrogenated amorphous silicon layer, TCO transparent conductive layer and silver grid lines together constitute the HJT cell structure suitable for the point-like film-opening efficiency improvement method.
[0027] Furthermore, the metal grid line includes fine grid lines, the film opening trajectory corresponds to the predetermined trajectory of the fine grid line, and multiple film opening points are arranged sequentially at intervals along the extension direction of the fine grid line.
[0028] As a preferred embodiment of the above, the metal grid lines include fine grid lines extending along the surface of the HJT battery. The fine grid lines are used to collect and export the charge carriers generated during battery operation. Before processing, according to the position of the fine grid lines in the metal grid line layout or screen printing stencil, an opening film trajectory consistent with the position of the fine grid lines is determined on the transparent conductive layer surface of the HJT battery semi-finished product, so that the opening film trajectory is within the coverage area of the subsequent fine grid lines. After determining the opening trajectory, the laser processing equipment is positioned according to the opening trajectory, so that the laser action path coincides with or substantially coincides with the predetermined trajectory of the fine gate line; point processing is performed along the extension direction of the fine gate line to form multiple opening points arranged at intervals on the opening trajectory; each opening point is arranged sequentially along the length direction of the fine gate line, and the opening points are distributed within the coverage area of the width of the fine gate line, so that the subsequently formed fine gate line can cover the opening points and contact the exposed silicon substrate at the opening points; The film-forming points are arranged at intervals, rather than continuously forming films along the entire length of the fine grid line. This arrangement creates multiple local contact positions below the fine grid line, with a transparent conductive layer, a hydrogenated amorphous silicon layer, and an a-Si silicon layer remaining between adjacent film-forming points. This allows for both local direct contact areas and passivation areas to be retained below the fine grid line. In actual implementation, the film-forming points can be evenly arranged along the direction of the fine grid line according to the length and width of the fine grid line and the cell layout to ensure a stable multi-point contact structure after the subsequent metal grid line covers the film-forming trajectory.
[0029] Furthermore, such as Figure 3 As shown, discrete point laser ablation uses an ultraviolet picosecond laser to continuously ablate the transparent conductive layer, the hydrogenated amorphous silicon layer, and the a-Si silicon layer, so that the ablation points are formed into point-like local film removal areas.
[0030] As a preferred embodiment of the above, discrete point laser film opening is performed using an ultraviolet picosecond laser device. Before processing, the HJT battery semi-finished product is fixed on the laser processing platform, with the transparent conductive layer facing the laser emission side, and coordinate positioning is completed according to the predetermined formation position of the metal grid lines. The laser processing device runs according to the preset film opening trajectory, so that the laser focus acts on multiple predetermined points on the surface of the transparent conductive layer in sequence. During the processing, the ultraviolet picosecond laser moves along the film-opening trajectory in a continuous dotting manner, and each laser action forms a dot-shaped local film removal area. The transparent conductive layer, hydrogenated amorphous silicon layer and a-Si silicon layer in the dot-shaped local film removal area are removed by the laser. The adjacent dot-shaped local film removal areas are kept apart, so that multiple film-opening points are formed on the film-opening trajectory, rather than forming continuous trenches or continuous strip-shaped film-opening areas. The ultraviolet picosecond laser has a short pulse width and a small heat-affected zone, which can reduce thermal diffusion and edge ablation during the film removal process. By adjusting the laser power, pulse repetition frequency, scanning speed, focal position, and dot spacing, the film removal range of a single opening point is limited to the coverage area of the metal grid line, and the opening point has a clear boundary. After continuous dot processing, a discrete opening structure consisting of multiple dot-shaped local film removal areas is formed on the opening trajectory. Subsequent metal grid lines can cover these opening points and use the opening points to form local contact channels.
[0031] Furthermore, the wavelength of the ultraviolet picosecond laser is 355nm.
[0032] As a preferred embodiment of the above, the ultraviolet picosecond laser device uses a laser source with a wavelength of 355nm; before processing, the HJT battery semi-finished product is fixed on the laser processing platform, so that the transparent conductive layer faces the laser incident direction, and the optical path calibration and focus positioning are completed according to the predetermined forming area of the metal grid line; the laser focus falls on the surface of the transparent conductive layer, and the processing path is consistent with the film opening trajectory. During processing, a 355nm ultraviolet picosecond laser continuously pokes along the film-opening trajectory, creating a localized film removal area at each laser point. This wavelength of ultraviolet laser can act on the transparent conductive layer, hydrogenated amorphous silicon layer, and a-Si silicon layer, removing these layers at the film-opening point and locally exposing the silicon substrate. Due to the short picosecond pulse duration, the thermal diffusion range during film removal is small, reducing the risk of edge melting, ablation propagation, and thermal damage to the silicon substrate. In practice, by adjusting the output power, scanning speed, pulse frequency, focal height, and dot spacing of the 355nm ultraviolet picosecond laser, the processing depth of a single opening point can reach the level of penetrating the transparent conductive layer, the hydrogenated amorphous silicon layer, and the a-Si silicon layer, while avoiding further damage to the silicon substrate by the laser. After processing, an exposed area of the silicon substrate is formed at the opening point, which can be contacted by subsequent metal gate lines. The transparent conductive layer, the hydrogenated amorphous silicon layer, and the a-Si silicon layer are still retained between adjacent opening points and in the area outside the opening trajectory.
[0033] Furthermore, the opening point is a circular opening point with a diameter of 45 μm and a point spacing of 200 μm between adjacent circular opening points.
[0034] As a preferred embodiment of the above, before laser processing, a dot-shaped processing pattern is set in the control program of the laser processing equipment according to the predetermined forming area of the metal grid line, and the target diameter of a single processing point is set to 45μm, so that each opening point forms a circular opening area on the surface of the transparent conductive layer; the diameter of the circular opening point can be controlled by adjusting the laser focus size, laser energy, number of pulses and processing focal length, so that the circular opening point can remove the transparent conductive layer, hydrogenated amorphous silicon layer and a-Si silicon layer, while avoiding the opening range from exceeding the coverage area of the metal grid line; Multiple circular opening points are arranged sequentially along the opening trajectory, with the center-to-center distance between adjacent circular opening points set at 200 μm. During processing, the laser processing equipment marks points one by one along the opening trajectory according to the preset point coordinates, so that each circular opening point is distributed at equal intervals. This point spacing allows the transparent conductive layer, hydrogenated amorphous silicon layer, and a-Si silicon layer to be retained between adjacent circular opening points, forming a continuous passivation region. It also allows the subsequent metal gate lines to form dispersed local direct contact with the silicon substrate through multiple circular opening points after covering the opening trajectory. After processing is completed, the diameter of the circular opening point and the center-to-center distance between adjacent circular opening points can be confirmed by microscopic observation or online visual inspection to ensure that the boundaries of the circular opening points are clear, the arrangement position is consistent with the opening trajectory, and the film layer between points remains intact. The above parameters enable the formation of a multi-point contact structure under the metal grid line, while reducing passivation damage caused by continuous opening.
[0035] Furthermore, the ultraviolet picosecond laser has a power of 70W, a processing speed of 2000mm / s, and forms multiple opening points through a single scan.
[0036] As a preferred embodiment of the above, a 355nm ultraviolet picosecond laser device is used to perform dot-shaped film opening processing on the HJT battery semi-finished product. Before processing, the HJT battery semi-finished product is fixed on the laser processing platform, with the transparent conductive layer facing the laser emission direction, and the positioning calibration is completed according to the predetermined forming area of the metal grid. The film opening trajectory and multiple film opening point coordinates are pre-imported into the laser processing program, so that the laser focus can act on each film opening point position sequentially along the film opening trajectory. During processing, the output power of the ultraviolet picosecond laser is set to 70W, the processing speed is set to 2000mm / s, and the film opening is completed in a single scan. The laser head moves along the film opening trajectory at a processing speed of 2000mm / s, and outputs laser energy at each predetermined film opening point position, so that the transparent conductive layer, hydrogenated amorphous silicon layer and a-Si silicon layer are removed and the silicon substrate is exposed. After the single scan is completed, multiple spaced film opening points are formed on the film opening trajectory, and point-like film opening processing can be completed without repeated scanning. During a single scan, the combination of 70W laser power and a processing speed of 2000mm / s ensures that each opening point has sufficient energy for removing the film, while avoiding expansion of the opening area or damage to the silicon substrate due to repeated scans. After processing, the position of the opening point, the opening boundary, and the film retention status between points can be confirmed by microscopic observation or online visual inspection, so that subsequent metal grid lines can cover the opening trajectory and form local direct contact with the silicon substrate through the opening point.
[0037] Furthermore, multiple opening points constitute discrete point contact regions for charge carriers to enter the metal gate line. The transparent conductive layer, hydrogenated amorphous silicon layer, and a-Si silicon layer retained between adjacent opening points and in the region outside the opening trajectory constitute a continuous passivation region, so that the metal gate line can form multiple direct contacts with the silicon substrate through the discrete point contact regions, and the surface passivation of the silicon substrate is maintained through the continuous passivation region.
[0038] As a preferred embodiment of the above, after the discrete point laser ablation is completed, multiple mutually separated ablation points are formed within the predetermined area for forming the metal gate line; the transparent conductive layer, hydrogenated amorphous silicon layer and a-Si silicon layer at each ablation point are removed, and the silicon substrate is locally exposed; the multiple ablation points are distributed along the ablation trajectory and together constitute a discrete point contact area, which is used to provide a local contact channel for charge carriers to enter the metal gate line after the subsequent metal gate line is formed; The transparent conductive layer, hydrogenated amorphous silicon layer, and a-Si silicon layer that were not removed by laser between adjacent opening points remain continuous. The transparent conductive layer, hydrogenated amorphous silicon layer, and a-Si silicon layer in the region outside the opening trajectory also remain intact, thus forming a continuous passivation region. The continuous passivation region covers most of the surface of the silicon substrate, which can continue to passivate the silicon substrate and maintain the light transmission and conductivity of the transparent conductive layer. During the fabrication of the metal grid lines, the metal paste covers the opening trajectory and fills each opening point in the discrete point contact region. After sintering, the metal grid lines form direct contact with the silicon substrate at multiple opening points, thereby forming a multi-point direct contact structure. When the battery is working, the charge carriers generated in the silicon substrate can migrate laterally to the adjacent opening points and enter the metal grid lines through the discrete point contact region to complete the collection. At the same time, the continuous passivation region maintains the passivation effect between the opening points and the area outside the opening trajectory, reducing the increase in surface recombination caused by the removal of the film layer over a large area.
[0039] Example 2; Based on the same inventive concept as the above-described method for improving efficiency of HJT battery grid line dot-matrix opening film, the present invention also provides a system for improving efficiency of HJT battery grid line dot-matrix opening film, the system comprising: The film opening trajectory determination module determines the film opening trajectory corresponding to the metal grid lines on the transparent conductive layer surface of the HJT battery semi-finished product, based on the grid line pattern of the metal grid lines to be formed. The dot-matrix laser ablation module performs discrete dot-matrix laser ablation on the transparent conductive layer, the hydrogenated amorphous silicon layer and the a-Si silicon layer along the ablation trajectory to form multiple ablation points arranged at intervals in a predetermined area corresponding to the metal gate line. The film-opening depth control and damage prevention module controls the film-opening depth of discrete point laser film opening, so that the transparent conductive layer, hydrogenated amorphous silicon layer and a-Si silicon layer at the film-opening point are removed to expose the silicon substrate, and the silicon substrate is not damaged by lattice. The film layer region retention module retains a transparent conductive layer, a hydrogenated amorphous silicon layer, and an a-Si silicon layer between adjacent film opening points and in the region outside the film opening trajectory. The gate contact forming module prepares metal gate lines on the surface of a transparent conductive layer with opening points, so that the metal gate lines cover the opening trajectory and form local direct contact with the silicon substrate through the opening points.
[0040] The system described above in this invention can effectively realize a method for improving the efficiency of point-like film opening under the grid line of HJT battery. The technical effects it can achieve are as described in the above embodiments, and will not be repeated here.
[0041] Example 3; Based on the same inventive concept as the method for improving efficiency of HJT battery grid line dot-shaped film opening under the aforementioned embodiment, the present invention also provides a computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a processor, can realize the method for improving efficiency of HJT battery grid line dot-shaped film opening under the aforementioned embodiment.
[0042] Example 4; To fully verify the innovation, superiority, and process stability of the dot-matrix laser-etched film process of this invention, multiple sets of control experiments were set up, using conventional un-etched HJT batteries and traditional strip-etched films batteries as comparison examples. Performance tests were carried out using a unified production substrate, unified equipment environment, and unified testing standards. The key parameters for comparison were the battery open-circuit voltage Voc, short-circuit current Isc, fill factor FF, photoelectric conversion efficiency, and minority carrier lifetime. All test samples used the same batch of N-type HJT silicon wafers and underwent uniform texturing, cleaning, double-sided a-Si passivation, and TCO coating processes. The laser equipment used was a 355nm ultraviolet picosecond laser. The ambient temperature, light intensity, and testing equipment for all samples were completely consistent, eliminating environmental, equipment, and material errors. The example was compared with three comparative examples. The example used a dot-matrix film-opening method below the gate line. The core process parameters were: dot diameter 45μm, dot spacing 200μm, 355nm UV picosecond laser, power 70W, speed 2000mm / s, and single scan. Its structural characteristics included forming discrete point contacts while completely preserving the a-Si layer and TCO transparent conductive layer between the dots, without damage to the silicon substrate. Comparative Example 1 was a traditional process without film opening, with the a-Si layer and TCO transparent conductive layer fully covered below the gate line, but without direct silver-silicon contact. Comparative Example 2 was the industry-leading linear full-film-opening process, continuously opening the film along the entire gate line, with the film width matching the gate line width. Although it formed direct silver-silicon contact along the entire line, the film layer below the gate line was completely removed, resulting in a large exposed silicon area. Comparative Example 3 was a large-pitch dot-matrix film-opening process, with the same dot diameter of 45μm, but the dot spacing increased to 350μm, resulting in sparser dots and a significant increase in carrier migration distance.
[0043] The performance test results show that the example achieves an open-circuit voltage of 752–755 mV, a short-circuit current of 42.85 A, a fill factor of 82.6%, a conversion efficiency of 23.95%, and a minority carrier lifetime of no less than 220 μs, demonstrating a significant improvement in open-circuit voltage with virtually no degradation in short-circuit current and minority carrier lifetime. In contrast, although Comparative Example 1 maintains intact passivation, severe recombination below the gate line results in an open-circuit voltage of only 740–742 mV and a conversion efficiency of 23.52%. Comparative Example 2, while increasing the open-circuit voltage to 748–750 mV, suffers from severe damage to the passivation structure, leading to a decrease in short-circuit current to 42.70 A and a minority carrier lifetime of 190 μs. Comparative Example 3, with its excessively large dot pitch resulting in insufficient carrier collection, has a fill factor of only 81.8% and a conversion efficiency of only 23.65%. Therefore, it can be seen that the embodiments, through a reasonable dot-shaped open-film structure, improve the open-circuit voltage while simultaneously ensuring passivation retention and carrier collection, resulting in an overall efficiency improvement superior to schemes without open film, strip-shaped open film, and large-pitch dot-shaped open film. As can be seen from the above embodiments and comparative examples, the present invention, by performing dot-shaped laser open film below the gate line, creates localized direct silver-silicon contact at the open film points, while retaining a passivation and light-transmitting film layer in the inter-point region. Compared to the process without open film, this effectively reduces interface recombination below the gate line, thereby significantly improving the battery open-circuit voltage; compared to the strip-shaped fully open film process, it avoids large-area damage to the passivation structure, maintaining a high minority carrier lifetime and short-circuit current stability; and compared to the large-pitch dot-shaped open film process, it ensures sufficient carrier collection and maintains a stable fill factor. This demonstrates that the present invention improves the open-circuit voltage while simultaneously ensuring passivation retention, carrier collection, and overall conversion efficiency improvement, exhibiting good process stability and practical application value.
[0044] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.
Claims
1. A method for improving efficiency of HJT battery with dotted film opening below the grid line, characterized in that, The method includes: On the surface of the transparent conductive layer of the HJT battery semi-finished product, the film opening trajectory corresponding to the metal grid line is determined according to the grid line pattern of the metal grid line to be formed. The HJT battery semi-finished product includes a silicon substrate and a hydrogenated amorphous silicon layer, an a-Si silicon layer and the transparent conductive layer formed sequentially on the surface of the silicon substrate. Discrete point-like laser ablation is performed on the transparent conductive layer, the hydrogenated amorphous silicon layer and the a-Si silicon layer along the ablation trajectory to form a plurality of ablation points arranged at intervals in a predetermined region corresponding to the metal gate line. The depth of the discrete point laser ablation is controlled so that the transparent conductive layer, the hydrogenated amorphous silicon layer and the a-Si silicon layer at the ablation point are removed to expose the silicon substrate, and the silicon substrate is not damaged by lattice. The transparent conductive layer, the hydrogenated amorphous silicon layer, and the a-Si silicon layer are retained between adjacent opening points and in the region outside the opening trajectory. The metal gate line is prepared on the surface of the transparent conductive layer where the opening point is formed, so that the metal gate line covers the opening trajectory and forms local direct contact with the silicon substrate through the opening point.
2. The method for improving efficiency of HJT battery grid line dot-shaped film opening according to claim 1, characterized in that, The HJT battery semi-finished product is formed by texturing and cleaning an N-type silicon wafer, and then depositing the hydrogenated amorphous silicon layer, the a-Si silicon layer, and the transparent conductive layer. The transparent conductive layer is a TCO transparent conductive layer, the hydrogenated amorphous silicon layer is an a-Si:H silicon layer, and the metal grid lines are silver grid lines.
3. The method for improving efficiency by dotted film opening below the grid line of an HJT battery according to claim 1, characterized in that, The metal grid line includes fine grid lines, the film opening trajectory corresponds to the predetermined trajectory of the fine grid line, and the plurality of film opening points are arranged sequentially at intervals along the extension direction of the fine grid line.
4. The method for improving efficiency by dotted film opening below the grid line of an HJT battery according to claim 1, characterized in that, The discrete point laser ablation process uses an ultraviolet picosecond laser to continuously ablate the transparent conductive layer, the hydrogenated amorphous silicon layer, and the a-Si silicon layer, so that the ablation points form point-like localized film removal areas.
5. The method for improving efficiency of HJT battery grid line dot-shaped film opening according to claim 4, characterized in that, The wavelength of the ultraviolet picosecond laser is 355nm.
6. The method for improving efficiency by dotted film opening below the grid line of an HJT battery according to claim 1, characterized in that, The opening point is a circular opening point with a diameter of 45 μm and a point spacing of 200 μm between adjacent circular opening points.
7. The method for improving efficiency of HJT battery grid line dot-shaped film opening according to claim 5, characterized in that, The ultraviolet picosecond laser has a power of 70W and a processing speed of 2000mm / s, and forms the multiple opening points through a single scan.
8. The method for improving efficiency of HJT battery grid line dot-shaped film opening according to claim 1, characterized in that, The plurality of opening points constitute discrete point contact regions for carriers to enter the metal gate line. The transparent conductive layer, the hydrogenated amorphous silicon layer and the a-Si silicon layer retained between adjacent opening points and in the region outside the opening trajectory constitute a continuous passivation region, so that the metal gate line can form multiple direct contacts with the silicon substrate through the discrete point contact regions, and the surface passivation of the silicon substrate is maintained through the continuous passivation region.
9. A point-like film-opening efficiency improvement system under the grid line of an HJT battery, characterized in that, The system includes: The film opening trajectory determination module determines the film opening trajectory corresponding to the metal grid lines on the transparent conductive layer surface of the HJT battery semi-finished product, based on the grid line pattern of the metal grid lines to be formed. The dot-matrix laser ablation module performs discrete dot-matrix laser ablation on the transparent conductive layer, the hydrogenated amorphous silicon layer and the a-Si silicon layer along the ablation trajectory to form multiple ablation points arranged at intervals in a predetermined area corresponding to the metal gate line. The film-opening depth control and damage prevention module controls the film-opening depth of discrete point laser film opening, so that the transparent conductive layer, hydrogenated amorphous silicon layer and a-Si silicon layer at the film-opening point are removed to expose the silicon substrate, and the silicon substrate is not damaged by lattice. The film layer region retention module retains a transparent conductive layer, a hydrogenated amorphous silicon layer, and an a-Si silicon layer between adjacent film opening points and in the region outside the film opening trajectory. The gate contact forming module prepares metal gate lines on the surface of a transparent conductive layer with opening points, so that the metal gate lines cover the opening trajectory and form local direct contact with the silicon substrate through the opening points.
10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which includes program instructions that, when executed by a processor, can implement the HJT battery grid line dot-shaped film opening efficiency improvement method as described in any one of claims 1-8.