A method for preparing nickel seed layer in low-power laser-guided windowed glass photovoltaic panels

Abstract

This application relates to the field of metallization technology for glass photovoltaic panels, and in particular to a method for preparing a nickel seed layer in a low-power laser-guided windowed glass photovoltaic panel. The method includes: obtaining a glass photovoltaic panel with a cover layer to be opened and a nickel-plated response layer; using a laser with a power lower than that required for complete removal in a single pass to perform multiple scans to form the windowed area; acquiring images to identify exposed and residual areas, and performing local compensation scans on residual areas causing discontinuities; determining the plating conditions based on the continuity of exposure and the distribution of residual material; and plating in a chemical nickel plating solution containing a nickel ion source, reducing agent, complexing agent, and stabilizer according to the plating conditions. This application can significantly reduce laser thermal damage while dynamically adjusting the concentration, load, and flow intensity of the complexing agent to ensure the formation of a continuous, low-resistance nickel seed layer in the low-power windowed area, avoiding plating failure and line breakage problems.

Description

Technical Field

[0001] This application relates to the field of metallization technology for glass photovoltaic panels, and in particular to a method for preparing a nickel seed layer for a low-power laser-opened glass photovoltaic panel. Background Technology

[0002] The conductive patterns on the surface of glass photovoltaic panels typically require low resistance, good adhesion, and high pattern precision, making them a key structure for photovoltaic modules to achieve photoelectric conversion and current harvesting. Currently, the industry commonly uses lasers to create grooves or windows in the functional film layers of glass photovoltaic panels to expose the underlying conductive or catalytic functional layers. Subsequently, a nickel seed layer is deposited in the exposed areas using a chemical plating process, providing a conductive foundation for subsequent copper or tin plating or the formation of conductive grid lines. Existing technical solutions typically use a fixed laser output power to perform a one-time scan to remove the capping layer, followed by direct immersion of the treated glass substrate in a chemical plating solution containing a nickel ion source, reducing agent, and complexing agent for deposition. This process is relatively fixed and relies heavily on preset equipment parameters to ensure the windowing effect and plating quality.

[0003] However, in existing technologies, when laser windowing power is significantly reduced to minimize thermal damage, incomplete removal of the coating layer in the windowed area can occur, resulting in island-like residues or continuous residual films. This leads to the inability of electroless nickel plating to initiate plating normally in some areas or the formation of a broken nickel seed layer. Furthermore, due to differences in film thickness, light absorption performance, and surface condition among different batches of glass photovoltaic panels, fixed laser power and fixed electroless plating parameters are difficult to adapt to fluctuations in actual windowing conditions. This results in unstable product yield under low power conditions, making it difficult to obtain a continuous, low-resistance nickel seed layer while ensuring low thermal damage. Summary of the Invention

[0004] This application provides a method for preparing a nickel seed layer in a low-power laser-driven windowed glass photovoltaic panel to solve the above-mentioned problems. The method includes:

[0005] S1. Obtain a glass photovoltaic panel, the glass photovoltaic panel comprising a glass substrate, a window cover layer disposed on the surface of the glass substrate, and a nickel-plated response layer located below the window cover layer;

[0006] S2. According to the preset conductive pattern, the laser power is lower than that required to completely remove the cover layer to be opened in a single scan, and the cover layer to be opened is scanned multiple times to expose the nickel-plated response layer along the preset conductive pattern, forming a window area.

[0007] S3. Acquire an image of the windowed area, identify the exposed area of ​​the nickel-plated response layer and the residual area of ​​the cover layer to be opened; when the residual area causes discontinuity in the exposed area, perform local compensation scanning based on the location of the residual area.

[0008] S4. Determine the corresponding plating conditions based on whether the exposed area after the compensated scan is continuous along the preset conductive pattern and the distribution state of the residual area within the window area.

[0009] S5. Immerse the glass photovoltaic panel in a chemical nickel plating solution containing a nickel ion source, reducing agent, complexing agent and stabilizer, and perform chemical nickel plating on the window area according to the plating start conditions to form a nickel seed layer continuously distributed along the preset conductive pattern.

[0010] Specifically, when the exposed area is continuous and there is a residual area in the windowed area that has not been cut off from the exposed area, compared to the case where there is no residual area in the windowed area, the concentration of the complexing agent in the electroless nickel plating solution is increased, the load on the glass photovoltaic panel corresponding to the unit volume of electroless nickel plating solution is reduced, and the flow intensity of the bath solution in the initial stage of electroless nickel plating is reduced.

[0011] Optionally, the average power of the laser acting on the surface of the glass photovoltaic panel is 0.10 to 0.20 W, and the covering layer to be opened is scanned two or three times, with a heat release interval set between adjacent scans.

[0012] Optionally, the first scan is used to reduce the bonding strength between the cover layer to be opened and the nickel-plated response layer, and subsequent scans are used to expose the nickel-plated response layer;

[0013] At least one subsequent scan trajectory is offset relative to the trajectory of the previous scan along the width direction of the preset conductive pattern to remove the cover layer to be opened at the edge of the windowed area.

[0014] Optionally, determining the window opening status of the window opening area includes:

[0015] Based on the image of the windowed area, determine the length of the nickel-plated response layer continuously exposed along the preset conductive pattern and the residual area of ​​the cover layer to be opened within the windowed area;

[0016] The window continuity rate is determined based on the ratio between the continuous exposure length and the target window length corresponding to the preset conductive pattern, and the residual coverage rate is determined based on the ratio between the residual area and the target area of ​​the window area.

[0017] The plating conditions corresponding to the windowed area are determined based on the windowed continuity rate and the residual coverage rate.

[0018] Optionally, the local compensation scan includes:

[0019] Identify the residual areas from the image of the windowed area that cause the discontinuity of the exposed area;

[0020] Generate a compensated scan trajectory corresponding to the residual region;

[0021] The laser is controlled to scan along the compensated scanning trajectory, avoiding areas in the windowed region where the nickel-plated response layer has been continuously exposed.

[0022] Optionally, the nickel ion source in the electroless nickel plating solution is selected from nickel sulfate, nickel chloride, or a combination of both;

[0023] The reducing agent is hypophosphite, and the complexing agent includes at least one selected from citrate, lactate, malate, and succinate.

[0024] The electroless nickel plating solution also contains a wetting agent for wetting the windowed area.

[0025] Optionally, the pH of the electroless nickel plating solution is adjusted to 6.5-6.9 using ammonia water. The ammonia water is mixed with a portion of the electroless nickel plating solution through a tank circulation pipeline or a premixing container and then added to the working tank. The temperature of the electroless nickel plating solution during electroless nickel plating is 65-75°C.

[0026] Optionally, for glass photovoltaic panels where there is no residual area within the windowed area, the concentration of the complexing agent is 18–22 g / L, and the load on the glass photovoltaic panel corresponding to a unit volume of electroless nickel plating solution is 0.3–0.5 dm² / L.

[0027] For glass photovoltaic panels with residual areas in the exposed area that have not been cut off within the windowed area, the concentration of the complexing agent is 22-25 g / L, the load on the glass photovoltaic panel corresponding to a unit volume of electroless nickel plating solution is 0.2-0.3 dm² / L, and a first bath flow intensity is used within 30-120 s after the glass photovoltaic panel is immersed in the electroless nickel plating solution, followed by a second bath flow intensity greater than the first bath flow intensity.

[0028] Optionally, during electroless nickel plating, the glass photovoltaic panel is vertically placed in the working tank, with the target surface having the windowed area facing the direction of the liquid flow, and the angle between the direction of the liquid flow and the extension direction of the preset conductive pattern is no greater than 45°.

[0029] A flow-blocking element is provided on the side of the glass photovoltaic panel away from the target surface, so that the turnover rate of the tank liquid on the back of the glass photovoltaic panel is less than the turnover rate of the tank liquid on the target surface.

[0030] Optionally, the content of the stabilizer is adjusted according to the age of the electroless nickel plating solution. A first stabilizer content is used in the first age stage, and a second stabilizer content higher than the first stabilizer content is used in the second age stage after the first age stage, and the electroless nickel plating time corresponding to the second age stage is extended.

[0031] The thickness of the nickel seed layer formed by the electroless nickel plating is 200-500 nm. The nickel seed layer is continuously distributed along the preset conductive pattern and is used as a conductive base layer for subsequent metal thickening treatment.

[0032] Through the above technical solution, this application achieves the following beneficial effects:

[0033] This application employs a laser with power lower than that required to completely remove the cover layer to be opened in a single scan, performing multiple scans to gradually weaken and remove the cover layer under repeated exposure to lower energy. This method can expose the nickel-plated response layer while reducing the instantaneous thermal shock caused by a single laser scan, minimizing excessive ablation at the window opening edge, film warping, and localized thermal damage to the glass substrate. This approach helps to balance the integrity of the window opening with the stability of the original film structure of the glass photovoltaic panel.

[0034] This application achieves this by setting a heat release interval between adjacent scans and offsetting the subsequent scan trajectory relative to the previous scan trajectory along the width direction of a preset conductive pattern, thereby gradually removing the cover layer from the center of the window area towards both sides. Compared to multiple overlapping trajectory scans, this method can reduce the residual cover layer at the window edge and avoid continuous heat concentration in the same location, thus improving the consistency of the window width and edge morphology.

[0035] This application acquires images of the windowed area after laser scanning, identifies the exposed area of ​​the nickel-plated response layer and the residual area of ​​the cover layer to be opened, and determines the subsequent processing method based on the continuous state of the exposed area. Therefore, this application does not judge whether the window opening is qualified solely based on the set power of the laser, but processes it based on the actual window opening result on the surface of the glass photovoltaic panel, which can reduce the impact of variations in film thickness, surface condition, and laser absorption performance between different batches on the window opening quality.

[0036] When residual areas cause discontinuities in the exposed area of ​​the nickel-plated response layer, this application generates a local compensation scan trajectory based on the location of the residual areas. Compensation scanning is performed only on the residual locations causing the truncation, avoiding areas that are already continuously exposed. This restores the continuity of the window opening while reducing unnecessary energy consumption and repeated thermal effects caused by repeatedly scanning all preset conductive patterns, thus lowering the risk of expanded ablation or interface damage in the already opened areas.

[0037] This application selects appropriate electroless nickel plating initiation conditions based on the distribution of residual coating layers within the windowed area. For windowed areas where non-cut-off residues still exist, increasing the complexing agent concentration, reducing the plate load per unit volume of plating solution, and decreasing the bath flow intensity during the initiation stage maintains relatively stable contact conditions between the plating solution and the limited exposed nickel response layer, which is beneficial for the formation of initial nickel nuclei. Increasing the bath flow intensity after the initial stage helps to continuously replenish nickel ions and reducing agents to the already plated area. This staged control method can reduce localized missed plating and broken nickel seed layer lines in the critical windowed area.

[0038] This application employs a chemical nickel plating solution containing a nickel ion source, hypophosphite reducing agent, carboxylate complexing agent, stabilizer, and wetting agent. The complexing agent maintains the stability of nickel ions at the operating temperature and pH, the wetting agent promotes the plating solution to enter the narrow linear window region, and the stabilizer inhibits nickel deposition in non-target areas and spontaneous decomposition of the plating solution, thereby facilitating the formation of selective and continuous nickel deposition within the laser-opened region.

[0039] This application preferably uses ammonia to adjust the pH of the electroless nickel plating solution, and the ammonia is first mixed with a portion of the plating solution in the bath circulation pipeline or premixing container before entering the working tank. This method can reduce the local pH surge caused by the concentrated addition of alkaline regulators, and reduce the possibility of local nickel salt precipitation, plating solution turbidity, and fluctuations in the initial plating state; at the same time, ammonia can also play an auxiliary complexing role, which is beneficial to maintaining the operational stability of the electroless nickel plating solution.

[0040] This application, by vertically arranging the glass photovoltaic panel so that the target surface with the windowed area faces the direction of the plating solution flow and aligns the flow direction of the plating solution with the extension direction of the preset conductive pattern, can reduce the retention of air bubbles in the narrow linear windowed area and improve the uniformity of plating solution renewal on the target surface. Furthermore, by installing a flow-blocking component on the back of the glass photovoltaic panel, the plating solution renewal rate on the back is lower than that on the target surface, which can also suppress parasitic nickel deposition on the back and reduce the occurrence of incomplete plating on the target surface and abnormal nickel deposition on the back.

[0041] This application adjusts the stabilizer content based on the age of the electroless nickel plating bath. When the bath age is low, a stabilizer content conducive to rapid plating initiation is used. In later stages, when byproducts gradually accumulate, the stabilizer content is increased, and the electroless plating time is adjusted accordingly. This method achieves a phased balance between plating initiation speed and bath stability, reducing the risk of bath turbidity, nickel precipitation on the bath walls, and spontaneous decomposition at higher bath ages, thus extending the effective operating cycle of the plating bath.

[0042] By employing low-power progressive windowing, windowing status detection, local compensation, and differentiated plating control, this application enables continuous deposition of nickel within the windowed area corresponding to a pre-defined conductive pattern, forming a thin nickel seed layer with conductive continuity. This nickel seed layer can serve as a conductive base layer for subsequent electroplating of copper, electroless copper plating, tin plating, or other metal thickening processes. This reduces the use of precious metal seed materials while providing a stable interface for further fabrication of conductive patterns on the glass photovoltaic panel surface. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a flowchart of the method for preparing the nickel seed layer of a low-power laser-driven windowed glass photovoltaic panel according to this application.

[0045] Figure 2 This is a schematic diagram of the film layer structure of a glass photovoltaic panel and the progressive low-power laser windowing process.

[0046] Figure 3 This is a schematic diagram of the microscopic image processing results for windowing continuity, residual coverage, and windowing response value.

[0047] Figure 4 A flowchart showing the switching of electroless nickel plating conditions corresponding to different window opening response levels.

[0048] Figure 5 This is a schematic diagram of the flow control of a glass photovoltaic panel on the target surface within a chemical plating bath.

[0049] Figure 6 This is a schematic diagram showing the adjustment of stabilizing additives in stages according to the age of the MTO tank.

[0050] Figure 7 This is a schematic diagram of the cross-sectional structure of the nickel seed layer in the windowed area. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0052] Furthermore, the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0053] The embodiments of this application will now be described in further detail with reference to the accompanying drawings.

[0054] Example 1

[0055] In existing technologies for fabricating conductive patterns on the surface of glass photovoltaic panels, a high-power laser is typically used to remove the functional film layer in a single step to form the windowed area, followed by electroless nickel plating. However, when attempting to reduce laser power to minimize thermal damage to the glass substrate and functional film layer, insufficient laser energy often leads to incomplete removal of the cover layer to be opened. In such cases, island-like residues or continuous residual film are prone to appear in the windowed area, directly hindering the initiation reaction of electroless nickel plating, resulting in broken nickel layers or no nickel plating at all. Furthermore, the film thickness and light absorption performance of different batches of glass photovoltaic panels vary, and fixed high-power or low-power processes are difficult to adapt to the fluctuations in actual windowed conditions. Moreover, existing processes lack a mechanism to establish a dynamic correspondence between the actual exposure state after windowing and the initiation conditions of electroless nickel plating, making process failures highly likely to occur in the low-power critical region.

[0056] Based on the above issues, please refer to Figure 1 , Figure 1 A flowchart illustrating a method for preparing a nickel seed layer in a low-power laser-driven windowed glass photovoltaic panel, as provided in this application embodiment, includes the following steps:

[0057] Step 1: Obtain a glass photovoltaic panel, which includes a glass substrate, a cover layer for opening a window disposed on the surface of the glass substrate, and a nickel-plated response layer located below the cover layer for opening a window;

[0058] The glass substrate serves as the base material supporting the entire photovoltaic module. Its material can be selected from tempered glass, ultra-clear patterned glass, or other materials with high light transmittance and mechanical strength. The cover layer to be opened can refer to a film layer applied to the surface of the glass substrate that needs to be partially removed in subsequent processes to expose the underlying functional layers. Specifically, it includes one or more combinations of transparent conductive oxide layers, inorganic insulating layers, organic protective layers, ink layers, glaze layers, or functional layers containing active particles. The nickel-plated responsive layer is located below the cover layer to be opened. It can refer to an interface layer that can directly induce electroless nickel plating after laser exposure, or that can induce electroless nickel plating after gentle cleaning, wetting, or pre-immersion treatment. This layer can be a transparent conductive oxide layer, an inorganic layer containing catalytic responsive particles, an interface layer containing nickel-affinity groups, or a functional layer in the glass photovoltaic panel that can be directly nickel-plated. After obtaining the glass photovoltaic panels, they are usually subjected to dust removal and degreasing treatment, such as cleaning with neutral or weakly alkaline cleaning solutions, followed by rinsing with deionized water and drying, in order to avoid the strong acid roughening process causing corrosion to the glass substrate or transparent conductive layer.

[0059] This step aims to provide a substrate with specific three-layer structural characteristics, clarify the functional positioning of each film layer, and lay the material basis for subsequent low-power laser selective removal and electroless nickel plating reaction.

[0060] Step 2: According to the preset conductive pattern, use a laser power lower than that required to completely remove the cover layer to be opened in a single scan to scan the cover layer to be opened multiple times, so that the nickel-plated response layer is exposed along the preset conductive pattern to form the window area.

[0061] The preset conductive pattern is a nickel seed layer distribution path determined according to the photovoltaic cell circuit design. The laser power, lower than the power required to completely remove the cover layer to be opened in a single scan, can refer to the actual average output power of the laser on the glass photovoltaic panel surface being significantly lower than the power required by traditional one-step molding processes (for example, traditional processes may require 0.7–0.8W, while this application preferably requires 0.10–0.20W, more preferably 0.14–0.18W). Multiple scans can refer to decomposing the removal task, which originally required a single high-energy impact, into two or three progressive scan processes with low energy density. The first scan is mainly used to reduce the bonding strength between the cover layer to be opened and the nickel-plated response layer or to pre-weaken the cover layer. Subsequent scans are used to completely remove the pre-weakened cover layer and expose the nickel-plated response layer. In some embodiments, the trajectory of at least one subsequent scan is offset by 2–10 μm relative to the trajectory of the previous scan along the width direction of the preset conductive pattern to effectively remove the remaining cover layer to be opened at the edge of the opening area. A heat release interval, ranging from 50ms to 5s, is set between two adjacent scans to prevent the heat generated by multiple scans from accumulating continuously in the same area, thereby significantly reducing the risk of thermal damage to the glass substrate and adjacent functional films. For example, when the preset conductive pattern is a line with a width of 100μm, a first scan with the same trajectory can be performed using a laser power of 0.16W. After an interval of 200ms, a second scan is performed with a 5μm offset along the width direction, thus achieving complete windowing without increasing the peak power of a single scan.

[0062] This multi-stage energy progressive laser action method transforms a high-energy single impact into a controllable heat accumulation process, ensuring continuous exposure of the nickel-plated response layer while effectively avoiding microcracks in the substrate or excessive ablation of the film layer caused by a single high-power laser action.

[0063] Step 3: Acquire images of the windowed area, identify the exposed area of ​​the nickel-plated response layer and the residual area of ​​the cover layer to be opened; when the residual area causes discontinuity in the exposed area, perform local compensation scanning based on the location of the residual area;

[0064] The image acquisition process involves real-time or offline monitoring of the laser-treated windowed area using optical microscopy, reflectivity detection, or machine vision inspection systems. The identification process includes calculating the windowing continuity rate C (the ratio of the actual continuously exposed nickel-plated response layer length to the target windowing length) and the residual coverage rate R (the ratio of the area still obscured by residual coating material within the windowed area to the target windowing area), thus obtaining the windowing response value Q, which characterizes the windowing quality. The formula is Q = C × (1 - R). The exposed area can refer to the region where the nickel-plated response layer is exposed and ready for direct plating; the residual area can refer to the region where the coating material to be opened has not been completely removed and still covers the nickel-plated response layer. When a residual area is detected causing a physical or electrical discontinuity in the exposed area (i.e., Q value is lower than a preset threshold, such as less than 0.65), the system automatically generates a compensation scan trajectory precisely corresponding to the location of the residual area. The laser is controlled to scan only along this compensation scan trajectory, strictly avoiding areas within the windowed area where the nickel-plated response layer is continuously exposed. For example, if image recognition shows that there is a 50μm long residual film of the coating layer that has not been removed at the corner of the conductive pattern, the laser head will only perform a spot scan on the 50μm segment, instead of repeatedly scanning the entire conductive pattern.

[0065] This step uses image recognition to drive closed-loop feedback, enabling the process to respond to the actual physical windowing state rather than preset fixed parameters. By using precise targeted local compensation scanning, the integrity of the windowing is improved while avoiding the overheating risk and efficiency loss caused by global rescanning.

[0066] Step 4: Determine the corresponding plating conditions based on whether the exposed area after compensation scanning is continuous along the preset conductive pattern and the distribution of the residual area within the windowed area.

[0067] The determination of the plating start conditions is a dynamic decision-making process based on the final detection results after compensation scanning. If the exposed area is continuous along the preset conductive pattern and has no residual area, it is determined to be a normal opening state, and conventional electroless nickel plating start conditions are adopted (such as a lower complexing agent concentration and a higher plate load). If the exposed area is continuous but there are still residual areas within the opening area that have not been cut off from the exposed area (i.e., the residue is distributed in an island-like pattern and has not caused a physical break in the conductive path; in this case, the Q value is in the critical range, such as 0.65 to 0.85), it is determined to be a window opening state that needs compensation. For the window opening state that needs compensation, the system automatically adjusts the plating start conditions: compared to the case where there is no residual area, it increases the complexing agent concentration in the electroless nickel plating solution, reduces the glass photovoltaic panel load per unit volume of electroless nickel plating solution, and reduces the flow intensity of the bath solution in the initial stage of electroless nickel plating. For example, when island-like residues in uncut exposed areas are detected, the complexing agent concentration is increased from the usual 18–22 g / L to 22–25 g / L, the plate load is reduced from 0.3–0.5 dm² / L to 0.2–0.3 dm² / L, and a low flow rate or intermittent flow mode is used for the first 30–120 seconds after entering the tank.

[0068] This step establishes the coupling relationship between the window opening response and the electroless plating initiation conditions, and implements differentiated process strategies for different window opening quality levels to ensure a stable plating environment even in the window opening region where the power threshold is low.

[0069] Step 5: Immerse the glass photovoltaic panel in a chemical nickel plating solution containing a nickel ion source, reducing agent, complexing agent and stabilizer, and perform chemical nickel plating on the window area according to the initial plating conditions to form a nickel seed layer continuously distributed along the preset conductive pattern.

[0070] The components of the electroless nickel plating solution include: a nickel ion source (selected from nickel sulfate, nickel chloride, or a combination thereof), a reducing agent (preferably a hypophosphite, such as sodium hypophosphite), a complexing agent (including at least one selected from citrate, lactate, malate, and succinate), and a stabilizer. A wetting agent may also be added to the plating solution to promote penetration into the narrow window area. The pH of the plating solution is preferably adjusted to 6.5–6.9 using ammonia. The ammonia is mixed with a portion of the electroless nickel plating solution via a bath circulation pipeline or a premixing container before being added to the working tank to avoid localized pH spikes that could cause turbidity. The temperature during electroless nickel plating is controlled at 65–75°C. When performing this step, strictly adhere to the aforementioned initial plating conditions: For cases where there are uncut exposed areas with residue, increase the complexing agent concentration to enhance the coordination stability and reduction selectivity of nickel ions at micro-defects, overcoming potential interfacial contamination or catalytic site shielding introduced by residues; utilize the reduced unit volume load to alleviate local concentration polarization caused by the decrease in effective catalytic area; and utilize the reduced initial bath flow intensity to reduce the scouring of primary nickel nuclei by turbulence, ensuring nucleation and anchoring on non-ideal exposed surfaces. Once continuous initial plating is detected in the open area (e.g., by color change, resistance decrease, or reaching a preset time), the bath circulation speed can be restored or increased for growth deposition until a continuous nickel seed layer with a thickness of 200–500 nm and a resistance of no more than 50 Ω is formed.

[0071] Therefore, by regulating the activity of nickel ions and deposition kinetics with complexing agents, and in conjunction with the coordinated regulation of load and flow field, the problem of plating failure or nickel layer breakage caused by local residual film after low-power windowing was effectively solved, forming a high-quality, low-resistance conductive base layer suitable for subsequent metal thickening treatment.

[0072] Example 2

[0073] In an optional embodiment, this application also provides specific implementation details of a method for preparing a nickel seed layer for a low-power laser-driven windowed glass photovoltaic panel based on the methods described in the above embodiments. Within the multi-scan framework determined in the above embodiments, this method further quantifies the laser power parameters, the number of scans, and the thermal management strategy to address the technical problem of balancing windowing efficiency and thermal damage control under low-power conditions.

[0074] Step 1: The average power of the laser applied to the surface of the glass photovoltaic panel is 0.10–0.20 W;

[0075] The average power refers to the measured power value of the laser beam transmitted through the optical path to the surface of the glass photovoltaic panel's cover layer to be opened. This power range is significantly lower than the 0.7–0.8 W typically used in traditional high-power grooving processes. Its purpose is to control the energy density of a single laser pulse below the critical threshold that is insufficient to instantly vaporize or shatter the cover layer to be opened, thereby avoiding microcracks in the glass substrate or excessive thermal ablation of the functional film layer. The determination of this power value is an adaptive setting based on the differences in film layer thickness, light absorption coefficient, and bonding strength among different batches of glass photovoltaic panels. When the film layer is thicker or the light absorption rate is lower, the upper limit of this range, such as 0.18 W or 0.20 W, can be used, while when the film layer is thinner or the thermal sensitivity is higher, the lower limit, such as 0.10 W or 0.12 W, can be used. For example, in a batch of glass photovoltaic panels using transparent conductive oxide as the nickel plating response layer, testing revealed that when the laser power was set to 0.14W, a single scan could not completely remove the outer ink coating layer, preventing subsequent electroless nickel plating from starting. Increasing the power to 0.16W partially removed the coating layer, but there was a risk of carbonization at the edges. Ultimately, by stabilizing the average power within the 0.10–0.20W range and employing a multi-scan strategy, the gradual peeling of the coating layer was successfully achieved without damaging the underlying structure. Limiting the average power to 0.10–0.20W effectively reduces the instantaneous thermal shock from a single scan, providing a safe thermal basis for subsequent step-by-step energy accumulation.

[0076] Step 2: Perform two or three scans on the cover layer to be opened;

[0077] The two or three scans refer to the repeated energy application process along a preset conductive pattern path using the aforementioned low-power laser on the same or adjacent trajectories. The main purpose of the first scan is to pre-weaken the capping layer to be opened, reducing its bonding strength with the underlying nickel-plated response layer, causing micro-stress relaxation or localized loosening within the capping layer. The subsequent second or third scans are used to further remove residual capping material based on the pre-weakening until the nickel-plated response layer is fully exposed. This segmented scanning configuration forms an energy-sharing mechanism, ensuring that the total input energy is sufficient to complete the windowing task, but it is distributed across multiple time segments, avoiding uncontrolled material phase transitions caused by a single high-energy injection. The number of scans can be dynamically adjusted based on the actual detected windowing continuity rate: if the residual coverage rate is still higher than a preset threshold after two scans, a third compensation scan is automatically triggered; if the ideal exposure state has been achieved after two scans, the scanning is terminated to save processing time. For example, when processing glass photovoltaic panels with a thick organic protective layer, a first 0.15W scan softens the protective layer, followed by a second 0.15W scan along the same trajectory to completely remove it. However, for structures combining inorganic and organic layers, a third scan with an offset trajectory may be needed to clean up any remaining residue at the edges. By employing two or three scans, the removal process of the capping layer can be more precisely controlled, ensuring continuous exposure of the nickel-plated response layer under low thermal load.

[0078] Step 3: Set a heat release interval between two adjacent scans;

[0079] The heat release interval refers to the period after the first laser scan is completed, during which the control system pauses laser output or moves the laser head to a non-processing area. This period allows heat accumulated on and near the surface of the glass photovoltaic panel to conduct into the substrate or dissipate to the surrounding environment. The heat release interval can be a fixed time delay or a dynamically adjusted variable based on real-time surface temperature monitoring. Its purpose is to prevent the heat from continuously accumulating in the same area due to continuous scanning, thereby avoiding carbonization of the cover layer to be opened, deactivation of the nickel-plated response layer due to overheating, or thermal stress deformation of the glass substrate. This interval is typically determined based on the laser repetition frequency, scanning speed, and the thermal diffusivity of the material, generally set in the range of milliseconds to seconds. For example, after the first scan, a 200ms heat release interval can be set to allow the cover layer temperature to quickly drop from its peak to near ambient temperature before the second scan. At this point, the material is in a cold or low-temperature state, and when it absorbs laser energy again, physical ablation rather than thermal decomposition occurs. By introducing a heat release interval, thermal stress concentration is effectively suppressed, ensuring the integrity of the optical performance and dimensional stability of the glass photovoltaic panel, while ensuring that the nickel-plated response layer still has good catalytic activity after exposure.

[0080] Example 3

[0081] One possible implementation is, such as Figure 2 The diagram shown is a schematic of a glass photovoltaic panel film layer structure and a progressive low-power laser windowing process provided in an embodiment of this application. The method also includes functional decoupling and trajectory optimization of the multiple scanning steps in the above embodiment.

[0082] Step 1: The first scan is used to reduce the bonding strength between the cover layer to be opened and the nickel-plated response layer, and subsequent scans are used to expose the nickel-plated response layer;

[0083] The first scan can refer to a process of pre-weakening the capping layer to be opened using a low-power laser. This step does not directly remove the capping layer, but rather uses photothermal effects to relax the polymer chains within the capping layer, promote microcracks, or loosen chemical bonds at the interface, thereby significantly reducing the bonding strength between it and the underlying nickel-plated response layer. This pre-weakening provides a low-energy-threshold peeling basis for subsequent scans, allowing for complete removal of the capping layer without the need for high power, thus avoiding thermal damage to the glass substrate or ablation of the functional film that could result from a single high-power scan. For example, when the capping layer to be opened is an organic insulating varnish with a thickness of approximately 200 nm, the first scan uses a laser power of 0.12 W, raising the surface temperature of the capping layer to near its glass transition temperature but not reaching its vaporization point. At this point, the van der Waals forces or hydrogen bonds at the interface between the capping layer and the nickel-plated response layer are weakened, and the bonding strength decreases to 30%–50% of its initial state. Subsequent scanning can refer to a second or third scan performed immediately after the first scan, or after a short heat release interval. Its purpose is to utilize the loosened interface state to completely peel the capping layer to be opened from the surface of the nickel-plated response layer with the same or slightly lower laser power, thereby exposing the nickel-plated response layer. Through the coordinated operation of the first and subsequent scans, a step-by-step peeling mechanism—softening the interface first and then removing the substrate—is achieved, effectively controlling cumulative heat input and ensuring the integrity of the nickel-plated response layer surface.

[0084] Step Two: At least one subsequent scan's trajectory is offset relative to the previous scan's trajectory along the width direction of the preset conductive pattern to remove the cover layer to be opened at the edge of the windowed area. Trajectory offset can refer to controlling the center path of the laser beam in the second or subsequent scans, moving it a specific distance perpendicular to the extension direction of the conductive pattern (i.e., the width direction) relative to the path of the first scan. This step is designed to specifically remove sidewall slag or fine residual film remaining at the edge of the windowed area due to thermal expansion anisotropy, cover layer adhesion gradient, or uneven laser spot energy distribution. Since the laser spot is typically Gaussian distributed with lower edge energy, if multiple scan trajectories completely overlap, residual bands are easily formed at the windowed edge. These residual bands can disrupt the continuity of subsequent electroless nickel plating or lead to insufficient adhesion at the nickel layer edges. By setting a trajectory offset, the effective range of the laser spot can be used to scrape or cut the edges of the previous scan path, thoroughly removing edge residues. Figure 2 As shown in the figure, this diagram details the offset relationship of the scanning trajectory during the progressive low-power laser windowing process. Trajectory T1 represents the path of the first pre-weakening scan, and trajectory T2 represents the path of the second exposure scan. Trajectory T2 is offset by a distance d along the width direction W relative to trajectory T1, so that the residual area R originally located at the edge of trajectory T1 is covered and removed by the high-energy region of trajectory T2. For example, when the linewidth of the preset conductive pattern is 40μm, the first scan is performed along the center line of the pattern, and the trajectory of the second scan can be offset to the left or right by 5μm to 10μm, or a three-scan strategy of center-left-right offset can be adopted to ensure that the overlay layer is uniformly and thoroughly removed throughout the entire linewidth range. This offset scanning method, combined with the pre-weakening scan, not only ensures continuous exposure of the center of the windowed area, but also significantly improves the cleanliness and roughness of the windowed edge, enhancing the mechanical bonding between the nickel seed layer and the substrate.

[0085] Example 4

[0086] In one optional embodiment, this application also provides a specific method for determining the opening state of the windowed area, which is based on quantitative analysis of the windowed area image collected in the above embodiment.

[0087] Step 1: Based on the image of the windowed area, determine the length of the nickel-plated response layer continuously exposed along the preset conductive pattern and the residual area of ​​the cover layer to be opened within the windowed area;

[0088] The image of the windowed area is acquired by an optical microscopic imaging system or machine vision inspection device from the surface of the glass photovoltaic panel after low-power laser scanning. The length of the nickel-plated response layer continuously exposed along the preset conductive pattern can refer to the linear cumulative length along the pattern path that is not obscured by the cover layer to be opened and can directly trigger the chemical nickel plating reaction. The residual area of ​​the cover layer to be opened within the windowed area can refer to the total projected area of ​​the cover layer that was not completely removed due to insufficient laser energy or scanning trajectory deviation within the preset window area. Specifically, the image processing algorithm first performs grayscale segmentation or edge extraction on the acquired image to identify the high-reflectivity nickel-plated response layer area and the low-reflectivity or specific textured residual areas of the cover layer to be opened. For example, when the preset conductive pattern is a straight line with a width of 50μm, the total number of pixels in the continuous bright area (representing the exposed nickel-plated response layer) on the straight line is calculated by pixel statistics and converted into physical length, while the total area of ​​the dark spots (representing the residual cover layer) is calculated. This image quantization method can transform microscopic surface morphology features into calculable geometric parameters, providing an objective data basis for subsequent evaluation of plating feasibility.

[0089] Step 2: Determine the window continuity rate based on the ratio between the continuous exposed length and the target window length corresponding to the preset conductive pattern, and determine the residual coverage rate based on the ratio between the residual area and the target area of ​​the windowed area.

[0090] Among them, the window continuity rate is a dimensionless index characterizing the topological connectivity of the conductive path, and its value equals the actual measured continuous exposure length divided by the target window length specified in the design drawings. The residual coverage rate is a dimensionless index characterizing the degree of interface contamination or shading, and its value equals the measured residual area divided by the design target area of ​​the windowed region. For example... Figure 3 As shown, Figure 3 This diagram illustrates the detection of windowing continuity rate, residual coverage rate, and windowing response value provided in this application. It details the process of extracting the continuous exposed segment L1 and residual patch A1 from the original microscopic image and indicates their correspondence with the target length L and target area A. The continuous exposed segment appears as a continuous bright band extending along the conductive pattern, while the residual patch appears as isolated dark spots scattered within the window. Specifically, if the target window length is 100 mm and the continuous exposed length measured by image recognition is 92 mm, the windowing continuity rate is 0.92; if the target window area is 5 mm² and the measured residual area is 0.8 mm², the residual coverage rate is 0.16. These two ratios together constitute a dual quantitative model for evaluating the quality of low-power laser windowing, reflecting the integrity of the electron conduction pathway and the availability of catalytic active sites, respectively.

[0091] Step 3: Determine the plating start conditions corresponding to the windowed area based on the window opening continuity rate and residual coverage rate;

[0092] like Figure 4 As shown, the opening status of the opening area is classified according to the opening continuity rate, residual coverage rate, or opening response value determined by both, and local compensation scanning, conventional plating conditions, or enhanced plating conditions are selected according to the opening status.

[0093] The process of determining the initial plating conditions involves mapping the two quantitative indicators mentioned above to specific electroless nickel plating process parameters. Specifically, the system combines the window opening continuity rate and residual coverage rate into an opening response value based on preset threshold rules, or directly matches different initial plating strategies based on the range distribution of the two. For example, when the window opening continuity rate is higher than 0.85 and the residual coverage rate is lower than 0.15, it is determined to be a normal opening state, and electroless nickel plating is performed using standard complexing agent concentration and plate load; when the window opening continuity rate is between 0.65 and 0.85 or the residual coverage rate is slightly higher but the exposed area is not cut off, it is determined to be a state requiring compensation. At this time, the complexing agent concentration in the electroless nickel plating solution is automatically increased to 22-25 g / L, the glass photovoltaic panel load per unit volume of bath solution is reduced to 0.2-0.3 dm² / L, and a lower bath solution flow intensity is used in the initial stage to promote crystal nucleation. This dynamic decision-making mechanism based on real-time detection data can effectively solve the problem of unstable initial plating caused by batch differences in film layers or fluctuations in laser power, ensuring that a continuous nickel seed layer can be obtained under different window opening qualities.

[0094] Example 5

[0095] In one possible implementation, this application also provides a local compensation scanning method for the problem of discontinuity in the windowed area, which specifically includes the following steps:

[0096] Step 1: Identify the residual areas causing discontinuities in the exposed area from the image of the windowed area;

[0097] Determining the residual area from the image involves using machine vision algorithms or image processing software to perform binarization segmentation and feature extraction on the microscopic image of the windowed area acquired in step S3. This identifies transitional areas with grayscale values ​​or reflectivities between the fully exposed nickel-plated response layer and the intact cover layer to be opened, marking these areas as residual islands or strips of residual film that disrupt the conductive path. Specifically, the system calculates the connectivity properties of pixels to filter out a set of residual coordinates that span the width of a preset conductive pattern and block potential current paths. For example, if image analysis detects a 15μm wide unremoved cover layer across the laser scan line, preventing physical connection between the exposed areas on either side, this 15μm wide area is identified as the residual area requiring processing. This precise positioning based on image features clarifies the target location for subsequent laser action, avoiding indiscriminate repeated scanning of the entire windowed area.

[0098] Step 2: Generate a compensated scan trajectory corresponding to the residual area;

[0099] The generation of the compensation scan trajectory refers to planning one or more matching laser motion paths based on the determined geometric contour, area, and distribution of the residual area. This trajectory generation process comprehensively considers the laser spot diameter, material ablation threshold, and heat-affected zone range, ensuring the trajectory completely covers the residual area while minimizing the scanning range. Specifically, if the residual area is an irregular island shape, a scanning path is generated that spirals or fills inwards around the edge of the island; if the residual area is elongated, a reciprocating scanning path is generated extending along its length. For example, for a strip-shaped residual with a width of 15 μm, the system can generate a rectangular filling trajectory with a length of 200 μm and a width slightly greater than 15 μm, with a safety margin of 2–5 μm at the trajectory edge to eliminate edge burrs. This trajectory serves as the basis for motion control commands, ensuring that compensation energy is accurately deposited at the target location, avoiding repair failure due to insufficient energy and preventing excessive heating of the substrate due to an excessively large scanning range.

[0100] Step 3: Control the laser to scan along the compensation scanning trajectory, avoiding areas in the windowed area where the nickel plating response layer has been continuously exposed;

[0101] The laser scanning control involves driving a laser galvanometer or motion platform to execute low-power laser irradiation strictly according to the compensated scanning trajectory generated above. Simultaneously, a no-entry zone is set in the control logic to prevent the laser beam from entering the area of ​​the nickel-plated response layer that has been identified as continuously exposed. The core of this step is to achieve minimally invasive repair, that is, applying removal energy only to the residual coating layer while protecting the exposed and catalytically active nickel-plated response layer below from secondary thermal damage or excessive ablation. Specifically, the laser output is turned on while moving along the compensated trajectory, and is immediately turned off or its power is significantly reduced once the motion coordinates deviate from the boundary of the continuously exposed area. For example, when performing the rectangular filling trajectory scan, the laser performs a single or double scan at a power of 0.14W only within the area covering the residue. When the scanning head moves to 2μm outside the edge of the residue, the laser output is immediately stopped, thus ensuring that the good plating interface already formed around it is not damaged. Through this spatially targeted repair operation, the problem of non-nickel plating caused by local residual film after low-power windowing is effectively solved, while avoiding the cumulative heat effect caused by global rescanning, ensuring the integrity of the glass substrate and functional film layer.

[0102] Example 6

[0103] In one optional embodiment, this application also provides a composition scheme for a chemical nickel plating solution, which is used to support the continuous and uniform deposition of a nickel seed layer on the complex interface formed by low-power laser windowing in the aforementioned step S5.

[0104] Step 1: The nickel ion source in the electroless nickel plating solution is selected from nickel sulfate, nickel chloride, or a combination of both;

[0105] In electroless nickel plating, the nickel ion source refers to the basic solute that provides metallic nickel ions for the reaction. Its function is to maintain a sufficient nickel ion concentration in the plating solution to support the continuous reduction deposition reaction. The nickel ion source is obtained by dissolving high-purity nickel sulfate crystals, nickel chloride crystals, or a mixture of both in deionized water. Specifically, nickel sulfate provides a stable nickel ion release rate, which is beneficial for controlling the stability of the deposition process; nickel chloride has higher solubility, which helps maintain the active concentration of nickel ions under high load or low temperature conditions. When a combination of nickel sulfate and nickel chloride is used, they work synergistically, utilizing the stability of nickel sulfate while improving the conductivity and dispersibility of the plating solution with the help of nickel chloride, thereby ensuring that nickel ions can be uniformly transported to the microscopic surface of the laser-windowed area. For example, when preparing the working bath, nickel sulfate hexahydrate can be selected as the main nickel source, with its concentration controlled in the range of 4–8 g / L, while a small amount of nickel chloride is added to adjust the chloride ion concentration, optimize anolyte dissolution, or replenish chloride ion loss. By selecting and matching this nickel source, deposition interruptions caused by insufficient nickel ion supply can be effectively avoided, especially when the exposed area is small and unevenly distributed after low-power windowing, thus ensuring the continuity of nickel crystal nuclei formation.

[0106] Step 2: The reducing agent is hypophosphite, and the complexing agent includes at least one selected from citrate, lactate, malate, and succinate;

[0107] Reducing agents refer to all chemical substances that provide electrons to reduce nickel ions to metallic nickel during electroless nickel plating. Their role is to initiate and maintain the autocatalytic deposition reaction on the catalytic surface. Reducing agents are obtained by adding hypophosphite salts such as sodium hypophosphite or potassium hypophosphite to the plating bath. During the reaction, hypophosphite not only reduces nickel ions but also undergoes a side reaction releasing phosphorus, making the formed nickel seed layer a nickel-phosphorus alloy. This imparts a certain degree of hardness and corrosion resistance to the plating layer and improves its adhesion as a base layer for subsequent electroplating. Complexing agents refer to organic acid anions used to form stable complexes with nickel ions, prevent their hydrolysis under alkaline or high-temperature conditions to form nickel hydroxide precipitate, and regulate the deposition rate. Complexing agents specifically include one or more combinations of citrate, lactate, malate, and succinate. These multi-component organic acid complexing agents not only stabilize nickel ions, but the multiple carboxyl and hydroxyl groups in their molecular structure can also coordinate with the active sites on the surface of the nickel-plated response layer, improving interfacial wettability and nucleation uniformity. For example, when the plating bath contains both sodium citrate and sodium lactate, citrate provides strong complexation stability, preventing turbidity caused by local pH fluctuations, while lactate helps accelerate the reaction kinetics in the initial nucleation stage. Furthermore, when addressing the situation of residual areas with uncut exposed regions as described in the above embodiments, a combination of malate and succinate is used. Utilizing their specific steric hindrance effect and buffering capacity, the spontaneous decomposition of non-catalytic regions can be further suppressed, while simultaneously promoting nickel layer growth at the residual edges, filling microscopic defects. Through the combined use of reducing agents and specific types of complexing agents, controllable plating is achieved on micro-roughness and interfaces containing trace amounts of residual material formed by low-power windowing, ensuring the density and functionality of the nickel seed layer.

[0108] Step 3: The electroless nickel plating solution also contains a wetting agent for wetting the windowed area.

[0109] Wetting agents, in this context, refer to surface-active substances that significantly reduce the interfacial tension between the plating solution and the glass photovoltaic panel surface. Their function is to eliminate capillary resistance caused by micro-grooves or slits within the laser-opened area, promoting full penetration of the plating solution and expelling air bubbles. Wetting agents are obtained by adding nonionic or anionic surfactants to the plating solution, typically at a concentration of 0.01–0.20 g / L. In low-power laser opening processes, due to the low laser energy, the resulting open area often has a large aspect ratio or a small amount of residual coating at the edges, leading to a large liquid-solid contact angle. This makes it difficult for the plating solution to completely wet the entire surface to be plated, easily resulting in pinholes or missed plating. The addition of a wetting agent allows the plating solution to quickly spread to every corner of the open area, including micron-level narrow slits and transitional roughening zones, ensuring that the catalytic reaction starts synchronously across the entire pre-defined conductive pattern. For example, using a nonionic wetting agent containing a polyoxyethylene ether structure maintains excellent foam stability and penetration even at operating temperatures of 65–75°C, effectively preventing plating line breaks caused by trapped air bubbles. The synergy between the wetting agent and the aforementioned complexing agent system not only solved the physical wetting problem, but also assisted the complexing agent in modifying the interface state by improving the mass transfer conditions, thus ensuring the complete coverage of the nickel seed layer under complex windowed conditions.

[0110] Example 7

[0111] In one possible implementation, this application also provides a method for pH adjustment and temperature control of the electroless nickel plating solution based on the above embodiments.

[0112] Step 1: Adjust the pH of the electroless nickel plating solution to 6.5-6.9 using ammonia water;

[0113] Ammonia water refers to an aqueous solution of ammonium hydroxide at a suitable concentration, which acts as a weak alkaline pH adjuster to replace traditional strong alkalis. Ammonia water exists in a dissociation equilibrium in solution, forming a buffer system with the complexing agent in the plating bath. This ensures a gradual increase in pH, preventing nickel ions from precipitating as hydroxides due to sudden, excessively high local pH levels. Specifically, the pH of the electroless nickel plating bath is stably controlled within the range of 6.5–6.9, which is the optimal activity window for the hypophosphite reduction of nickel ions. For example, when the initial pH of the plating bath is 5.8, the pH is gradually increased to 6.7 by adding 25% ammonia water. During this process, the transparency of the bath is observed to confirm the absence of turbidity or flocculent precipitate. This weak alkaline adjustment method not only achieves precise pH control but also enhances the stability of nickel ions by utilizing the coordination ability of ammonia molecules, effectively solving the technical problems of bath turbidity and subsequent nickel plating failure caused by strong alkaline adjustments.

[0114] Step 2: Ammonia water is mixed with a portion of the electroless nickel plating solution through the tank solution circulation pipeline or premixing container and then added to the working tank;

[0115] The bath circulation pipeline refers to the liquid delivery pipeline connecting the working tank to the filtration system or heating system, and the premixing container refers to a small mixing tank independent of the main working tank. This step defines the ammonia addition path and mixing method, prohibiting the direct injection of high-concentration ammonia into the working tank containing the glass photovoltaic panels. In practice, ammonia is injected into the operating bath circulation pipeline, or first injected into the premixing container and thoroughly mixed with a portion of the plating solution drawn from the working tank. After uniform mixing, it is then returned to the main working tank. For example, in a 200L electroless nickel plating tank, a 10L premixing container is set up. Plating solution is drawn from the main tank into this container, a calculated amount of ammonia is added, and the mixture is stirred for 2-3 minutes until the pH is uniform. Then, the mixture is pumped back to the main tank. This surface mixing or pre-dilution addition strategy eliminates the risk of excessively high local concentrations at the ammonia addition point, ensures the homogeneity of pH changes in the entire bath system, prevents nickel salt precipitation caused by local pH abrupt changes, and guarantees the stability of the plating environment in the low-power laser windowed area.

[0116] Step 3: The temperature for electroless nickel plating is 65-75℃.

[0117] Here, temperature refers to the actual operating temperature of the plating bath during the electroless nickel plating reaction. This temperature range is determined based on the kinetic characteristics of the hypophosphite reduction reaction, aiming to provide sufficient activation energy to drive the nickel deposition reaction, while avoiding excessively high temperatures that cause rapid decomposition of the plating bath or excessively low temperatures that cause reaction stagnation. Specifically, the plating bath temperature is maintained constant between 65 and 75°C using a plating bath heating system. For example, setting and controlling the plating bath temperature at 70°C provides a moderate hypophosphite reduction rate, enabling the formation of dense and continuous nickel nuclei within the micro-windowed area created by the low-power laser, and their growth at a stable rate. If the temperature is below 65°C, the activation energy is insufficient, potentially leading to a significantly prolonged plating time or even failure to plating in areas with high residual coverage; if the temperature is above 75°C, it may accelerate the spontaneous decomposition of the plating bath, increasing the risk of nickel precipitation on the bath walls. Therefore, this temperature limit, in conjunction with the aforementioned pH adjustment method and complexing agent system, works synergistically to create a stable electroless nickel plating environment suitable for low-power laser-windowed photovoltaic panels.

[0118] Example 8

[0119] In one embodiment, this application also provides a method for adjusting electroless nickel plating parameters under specific window opening conditions. Based on the determination of whether there are residual areas of uncut exposed areas in the previously determined window opening region, this method differentiates the component concentration of the electroless nickel plating solution, the plate load, and the bath flow strategy to address the impact of microscopic interface defects on the continuity of macroscopic plating.

[0120] Step 1: For glass photovoltaic panels with no residual area in the windowed area, the concentration of the complexing agent is 18-22 g / L, and the load on the glass photovoltaic panel corresponding to a unit volume of electroless nickel plating solution is 0.3-0.5 dm² / L;

[0121] The absence of residual areas refers to a state where, after the aforementioned image recognition and compensation scanning, the nickel plating response layer is completely and continuously exposed along the preset conductive pattern, and there are no island-like or film-like coatings remaining in the windowed area. In this state, the catalytic active sites on the surface of the glass photovoltaic panel are evenly distributed, resulting in low plating resistance. The complexing agent refers to a chemical component used to stabilize nickel ions in the plating solution, prevent their spontaneous decomposition, and regulate the deposition rate. Specifically, it may include at least one of citrate, lactate, malate, and succinate. When the windowing quality is good, the complexing agent concentration is maintained within the conventional range of 18–22 g / L, which is sufficient to balance the stability of the plating solution and the deposition rate. The glass photovoltaic panel load per unit volume of electroless nickel plating solution can be the ratio of the effective windowed area of ​​the glass photovoltaic panel in the working tank to the volume of the plating solution. Controlling the load at 0.3–0.5 dm² / L ensures that the consumption and replenishment of nickel ions in the plating solution are dynamically balanced per unit time, avoiding excessively rapid aging of the plating solution due to excessively low load, or local concentration polarization due to excessively high load. For example, in a 100L working tank, if a glass photovoltaic panel with a total effective window area of ​​40dm² is placed, the load is 0.4dm² / L. With a complexing agent concentration of 20g / L, rapid and uniform nickel layer growth can be achieved at a temperature of 65–75℃. This conventional parameter configuration allows for the production of nickel seed layers with uniform thickness and low resistivity while ensuring production efficiency.

[0122] Step 2: For glass photovoltaic panels with residual areas of uncut exposed areas within the windowed area, the concentration of the complexing agent is 22-25 g / L, the load on the glass photovoltaic panel corresponding to a unit volume of electroless nickel plating solution is 0.2-0.3 dm² / L, and the first bath flow intensity is used within 30-120 s after the glass photovoltaic panel is immersed in the electroless nickel plating solution, followed by the use of a second bath flow intensity greater than the first bath flow intensity.

[0123] The residual areas with uncut exposed regions refer to areas where, although the nickel plating response layer remains macroscopically connected, a small amount of coating residue still exists at the microscopic scale. These residues may adsorb organic impurities or alter the local charge distribution, thus increasing the difficulty of initiating plating. For glass photovoltaic panels in this critical state, the complexing agent concentration is first increased to 22–25 g / L. A higher complexing agent concentration can enhance the coordination stability of nickel ions, suppress the competitive adsorption of impurity ions at defect sites, and improve the nucleation selectivity of nickel crystal nuclei at the edges of residues or non-ideal surfaces. Secondly, the glass photovoltaic panel load per unit volume of electroless nickel plating solution is reduced to 0.2–0.3 dm² / L. Reducing the load alleviates the reaction burden per unit volume of plating solution, mitigates the concentration polarization phenomenon caused by the relative reduction in effective catalytic area, and provides a more sufficient reaction time window for initiating plating in difficult areas. Furthermore, a staged bath flow intensity control strategy is adopted. During the initial 30–120 s after the glass photovoltaic panel is immersed in the electroless nickel plating solution, a first bath flow intensity is used, which is relatively low or intermittent. The low flow rate environment at this stage helps reduce the scouring effect of fluid shear force on the newly formed tiny nickel nuclei, allowing the nickel nuclei to anchor firmly at the defect interface with residual interference, completing the crucial nucleation process. Once continuous plating initiation is detected in the windowed area (e.g., by color change or a decrease in resistance), the flow rate is immediately switched to a second bath flow rate greater than the first. This high-flow-rate second stage aims to accelerate the diffusion of reaction products and the replenishment of fresh plating solution, ensuring rapid nickel layer growth and preventing localized depletion. Figure 5 As shown, Figure 5 This diagram illustrates the flow control of the glass photovoltaic panel in the electroless plating bath provided in this application. It details the path of the liquid flowing through the target surface of the vertically positioned glass photovoltaic panel in the plating bath and the flow field distribution at different stages. The initial flow field is relatively gentle to facilitate nucleation, while the flow field intensifies in subsequent stages to promote mass transport. For example, for a batch of glass photovoltaic panels with a window opening response value Q of 0.75, after immersing them in the plating bath, the frequency of the bath circulation pump is controlled at 20Hz (first intensity) for the first 60 seconds. After observing the color change of the lines, the frequency is increased to 40Hz (second intensity), while maintaining the complexing agent concentration at 24g / L and the loading at 0.25dm² / L. This successfully forms a continuous nickel seed layer in areas that were previously difficult to plating. Through the synergistic effect of increasing the complexing agent concentration, reducing the loading, and segmented flow control, the problem of nickel not being applied or broken lines caused by residues after low-power laser window opening is effectively overcome.

[0124] Example 9

[0125] In one possible implementation, this application also provides a method for optimizing the flow field distribution during electroless nickel plating to suppress parasitic deposition on the back side. This method, based on any of the low-power laser windowing and plating start-up condition determination steps in the foregoing embodiments, further ensures preferential and continuous formation of a nickel seed layer on the target surface through physical layout and fluid dynamics control.

[0126] Step 1: Place the glass photovoltaic panel vertically in the working tank, so that the target surface with the windowed area faces the direction of the tank liquid flow, and the angle between the direction of the tank liquid flow and the extension direction of the preset conductive pattern is no greater than 45°.

[0127] Vertical setup refers to the glass photovoltaic panel's surface normal direction being parallel to the horizontal plane, and the panel surface being perpendicular to the bath solution surface or suspended at a slight angle on the fixture. This setup utilizes gravity to help expel air bubbles adhering to the panel surface and reduces the concentration gradient difference between the upper and lower surfaces caused by horizontal placement. The target surface facing the bath solution flow direction means that the mainstream vector of the bath solution directly impacts or flows parallel to the windowed area to be nickel plated, thereby creating a high shear force at the target surface boundary layer. This accelerates the mass transfer process of nickel ions and reducing agents into the laser-opened microstructure, avoiding delayed plating due to an excessively thick diffusion layer. The angle between the bath solution flow direction and the extension direction of the preset conductive pattern is no greater than 45°, ensuring that the fluid streamlines are as parallel as possible to the conductive pattern (such as grid lines or busbar paths) or intersect at a small angle. For example, when the preset conductive pattern is a longitudinally extending parallel grid line, the flow direction of the plating solution should be adjusted to be consistent with the direction of the grid line or the angle should be controlled within 30°. If the angle is too large (such as a near 90° perpendicular intersection), the fluid is prone to generate eddies or cavitation at the edge of the narrow-line opening, causing bubbles to be trapped in the laser-etched trenches, hindering the plating solution from contacting the bottom nickel plating response layer, and thus causing line breakage or incomplete plating. Through this small-angle matching, the plating solution can be effectively guided to flow smoothly through the pattern gaps, carrying away the hydrogen gas generated by the reaction, and ensuring that each point in the opening area receives uniform ion replenishment.

[0128] Step 2: Install a flow deflector on the side of the glass photovoltaic panel away from the target surface to ensure that the turnover rate of the tank liquid on the back of the glass photovoltaic panel is less than that on the target surface.

[0129] In this context, a flow-blocking component refers to a physical barrier structure placed near the non-target surface (i.e., the back side) of the glass photovoltaic panel. Its material is typically a chemically resistant, non-conductive material, such as polytetrafluoroethylene (PTFE), polypropylene (PP), or a corrosion-resistant metal mesh. The flow-blocking component is positioned between the back side of the glass photovoltaic panel and the working tank wall or adjacent panels to increase the local resistance of the back flow channel. The tank solution turnover rate refers to the volume of fresh plating solution flowing through a unit area per unit time. Reducing the turnover rate on the back side aims to limit the frequency of contact between back-side catalytic sites (such as intentionally exposed edges or unintentional defects) and high concentrations of nickel ions and reducing agents. Specifically, the flow-blocking component can be a perforated plate or solid baffle parallel to the glass photovoltaic panel, with a distance of 2mm to 20mm between it and the back side of the panel. For example, when the glass photovoltaic panel is vertically immersed in the tank solution, installing a baffle with a low porosity on the back side forces most of the circulating pump-driven plating solution to flow around the back side towards the target surface with less resistance, or keeps the fluid flowing through the back side in a laminar or even quasi-static state. At this point, the target surface, being directly facing the flow and unobstructed, is in a state of high-speed turbulence or forced convection, while the back surface is in a state of low-speed diffusion. This velocity difference not only physically reduces the probability of autocatalytic deposition on the back surface but also creates a pressure gradient on both sides of the plate, further promoting the preferential wetting and coverage of the open area of ​​the target surface by the plating solution. This step, in conjunction with the orientation setting mentioned above, together constructs an asymmetric flow field environment: the target surface receives a sufficient supply of reactants for rapid nucleation and growth, while the back surface, due to the low-solvent and low-velocity environment, is inhibited from unintended parasitic deposition, thus solving the common technical problem of nickel deposition on the back surface but not on the front surface when operating in large tanks or with multiple plates in parallel.

[0130] Example 10

[0131] In another optional embodiment, this application also provides a method for dynamically adjusting the stabilizer content and controlling the final state of the nickel seed layer based on the age of the electroless nickel plating bath. This method, based on the electroless nickel plating bath composition of the above embodiments, further introduces a time-dimensional process control variable to resolve the contradiction between the decrease in stability caused by the accumulation of by-products and the slow start-up of plating during long-term operation of the plating bath.

[0132] Step 1: Adjust the stabilizer content according to the age of the electroless nickel plating solution. Use the first stabilizer content in the first age stage, and use the second stabilizer content higher than the first stabilizer content in the second age stage after the first age stage, and extend the electroless nickel plating time corresponding to the second age stage.

[0133] The term "tank age" refers to the number of cycles required for the cumulative amount of nickel metal added to the electroless nickel plating bath during production to reach the amount of nickel metal present in the bath at the time of initial setup. It is typically measured in MTO (Metal Turn Over). As MTO increases, the concentration of byproducts such as phosphites in the bath gradually rises, the state of nickel ions changes, and the number of catalytically active sites for trace impurities or suspended nickel powder increases, leading to a significant increase in the risk of spontaneous decomposition of the bath.

[0134] like Figure 6 As shown, this embodiment uses 1.0 MTO as the dividing line to divide the electroless nickel plating solution into a first stage and a second stage, and sets the stabilizer content and electroless nickel plating time for the two stages respectively.

[0135] The first bath age stage typically corresponds to the initial stage of bath operation, such as when the bath age is less than 1.0 MTO. During this stage, the bath system is relatively pure, with less accumulation of byproducts. To shorten the induction period in the low-power laser windowing area and achieve rapid plating initiation, a lower first stabilizer content is used. For example, when the stabilizer is a lead-, bismuth-, or organosulfur compound, its content can be controlled within the range of 1–3 ppm. This low concentration is sufficient to suppress unintended homogeneous nucleation without excessively occupying the catalytically active sites exposed by the laser, thus ensuring a faster deposition rate.

[0136] The second tank age stage corresponds to the middle to late stage of tank operation, i.e., the stage after the first tank age stage, for example, when the tank age is in the range of 1.0–2.5 MTO. During this stage, due to the cumulative effect of byproducts, the stability threshold of the tank solution decreases, making it highly susceptible to nickel deposition on the tank walls or turbidity. Therefore, a higher concentration of the second stabilizer than the first stabilizer must be used, for example, increasing the stabilizer concentration to 3.5–5 ppm. This increased stabilizer concentration allows for stronger adsorption onto impurity particles or microcrystalline nuclei on non-catalytic surfaces, effectively blocking heterogeneous nucleation pathways and preventing spontaneous decomposition of the tank solution.

[0137] However, increasing the stabilizer content leads to competitive adsorption on the catalytic surface of the windowed area of ​​the glass photovoltaic panel, resulting in a prolonged initial reaction time. To compensate for this kinetic lag and ensure the nickel layer reaches the predetermined thickness, the electroless nickel plating time needs to be extended accordingly in the second plating stage. For example, if the plating time in the first plating stage is 7–10 minutes, the plating time in the second plating stage can be extended by 1–5 minutes, adjusted to 10–15 minutes. This synergistic strategy of high stabilizer content and long plating time maintains the long-term operational stability of the plating solution under high plating stages while ensuring the complete formation of the nickel seed layer on the product side.

[0138] Step 2: The thickness of the nickel seed layer formed by electroless nickel plating is 200-500 nm. The nickel seed layer is continuously distributed along the preset conductive pattern and is used as the conductive base layer for subsequent metal thickening treatment.

[0139] The thickness of the nickel seed layer is a final physical morphology indicator determined by controlling the reaction time and deposition rate of electroless nickel plating. The thickness range of 200–500 nm is limited based on a balance between conductivity and mechanical stress: if the thickness is less than 200 nm, the nickel layer may have microscopic pores, leading to excessively high resistance (e.g., exceeding 50 Ω), which can easily cause uneven current distribution or through-pore defects during subsequent copper plating; if the thickness exceeds 500 nm, it not only increases the consumption of precious metals but also may lead to peeling or detachment between the nickel layer and the glass substrate or functional film due to accumulated internal stress.

[0140] The continuous distribution of the nickel seed layer along the pre-defined conductive pattern means that, under a microscope, the nickel layer shows no breaks or pinholes along the laser windowing path, forming a complete conductive path. This continuity is a prerequisite for the conductive base layer in subsequent metal thickening processes. Only with a continuous, low-resistance nickel seed layer can subsequent electroplating, electroless copper plating, or tin plating processes uniformly deposit metal on the nickel layer surface, forming a low-resistance main electrode that meets the requirements of photovoltaic cell grid lines.

[0141] like Figure 7 As shown, Figure 7 This is a schematic cross-sectional view of the nickel seed layer in the windowed area provided in this application. As can be clearly seen from the figure, a nickel-plated response layer and a continuous, dense nickel seed layer are sequentially disposed above the glass substrate. The nickel seed layer is strictly limited within the width defined by the laser windowing, exhibiting uniform thickness and good interfacial bonding, without any parasitic deposition spreading to the non-windowed areas. This structure visually demonstrates the high-quality nickel seed layer morphology obtained after a segmented bath age control process, verifying that by dynamically adjusting the stabilizer content and plating time, a continuously distributed functional layer meeting the thickness requirements of 200–500 nm can be obtained under different bath age conditions.

[0142] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing a nickel seed layer in a low-power laser-driven windowed glass photovoltaic panel, characterized in that, include: S1. Obtain a glass photovoltaic panel, the glass photovoltaic panel comprising a glass substrate, a window cover layer disposed on the surface of the glass substrate, and a nickel-plated response layer located below the window cover layer; S2. According to the preset conductive pattern, the laser power is lower than that required to completely remove the cover layer to be opened in a single scan, and the cover layer to be opened is scanned multiple times to expose the nickel-plated response layer along the preset conductive pattern, forming a window area. S3. Acquire an image of the windowed area, identify the exposed area of ​​the nickel-plated response layer and the residual area of ​​the cover layer to be opened; when the residual area causes discontinuity in the exposed area, perform local compensation scanning based on the location of the residual area. S4. Determine the corresponding plating conditions based on whether the exposed area after the compensated scan is continuous along the preset conductive pattern and the distribution state of the residual area within the window area. S5. Immerse the glass photovoltaic panel in a chemical nickel plating solution containing a nickel ion source, reducing agent, complexing agent and stabilizer, and perform chemical nickel plating on the window area according to the plating start conditions to form a nickel seed layer continuously distributed along the preset conductive pattern. Specifically, when the exposed area is continuous and there is a residual area in the windowed area that has not been cut off from the exposed area, compared to the case where there is no residual area in the windowed area, the concentration of the complexing agent in the electroless nickel plating solution is increased, the load on the glass photovoltaic panel corresponding to the unit volume of electroless nickel plating solution is reduced, and the flow intensity of the bath solution in the initial stage of electroless nickel plating is reduced.

2. The method according to claim 1, characterized in that, The laser applied to the surface of the glass photovoltaic panel has an average power of 0.10 to 0.20 W, and the covering layer to be opened is scanned two or three times, with a heat release interval set between adjacent scans.

3. The method according to claim 2, characterized in that, The first scan is used to reduce the bonding strength between the cover layer to be opened and the nickel-plated response layer, and subsequent scans are used to expose the nickel-plated response layer. At least one subsequent scan trajectory is offset relative to the trajectory of the previous scan along the width direction of the preset conductive pattern to remove the cover layer to be opened at the edge of the windowed area.

4. The method according to claim 1, characterized in that, Determining the window opening status of the window opening area includes: Based on the image of the windowed area, determine the length of the nickel-plated response layer continuously exposed along the preset conductive pattern and the residual area of ​​the cover layer to be opened within the windowed area; The window continuity rate is determined based on the ratio between the continuous exposure length and the target window length corresponding to the preset conductive pattern, and the residual coverage rate is determined based on the ratio between the residual area and the target area of ​​the window area. The plating conditions corresponding to the windowed area are determined based on the windowed continuity rate and the residual coverage rate.

5. The method according to claim 4, characterized in that, The local compensation scan includes: Identify the residual areas from the image of the windowed area that cause the discontinuity of the exposed area; Generate a compensated scan trajectory corresponding to the residual region; The laser is controlled to scan along the compensated scanning trajectory, avoiding areas in the windowed region where the nickel-plated response layer has been continuously exposed.

6. The method according to claim 1, characterized in that, The nickel ion source in the electroless nickel plating solution is selected from nickel sulfate, nickel chloride, or a combination of both. The reducing agent is hypophosphite, and the complexing agent includes at least one selected from citrate, lactate, malate, and succinate. The electroless nickel plating solution also contains a wetting agent for wetting the windowed area.

7. The method according to claim 6, characterized in that, The pH of the electroless nickel plating solution is adjusted to 6.5-6.9 using ammonia water. The ammonia water is mixed with a portion of the electroless nickel plating solution through a tank circulation pipeline or a premixing container and then added to the working tank. The temperature of the electroless nickel plating solution during electroless nickel plating is 65-75℃.

8. The method according to claim 6, characterized in that, For glass photovoltaic panels where there is no residual area within the windowed area, the concentration of the complexing agent is 18–22 g / L, and the load on the glass photovoltaic panel corresponding to a unit volume of electroless nickel plating solution is 0.3–0.5 dm² / L. For glass photovoltaic panels with residual areas in the exposed area that have not been cut off within the windowed area, the concentration of the complexing agent is 22-25 g / L, the load on the glass photovoltaic panel corresponding to a unit volume of electroless nickel plating solution is 0.2-0.3 dm² / L, and a first bath flow intensity is used within 30-120 s after the glass photovoltaic panel is immersed in the electroless nickel plating solution, followed by a second bath flow intensity greater than the first bath flow intensity.

9. The method according to claim 1, characterized in that, When performing electroless nickel plating, the glass photovoltaic panel is vertically placed in the working tank, with the target surface where the window area is formed facing the direction of the liquid flow, and the angle between the direction of the liquid flow and the extension direction of the preset conductive pattern is no greater than 45°. A flow-blocking element is provided on the side of the glass photovoltaic panel away from the target surface, so that the turnover rate of the tank liquid on the back of the glass photovoltaic panel is less than the turnover rate of the tank liquid on the target surface.

10. The method according to claim 6, characterized in that, The content of the stabilizer is adjusted according to the age of the electroless nickel plating solution. A first stabilizer content is used in the first age stage, and a second stabilizer content higher than the first stabilizer content is used in the second age stage after the first age stage, and the electroless nickel plating time corresponding to the second age stage is extended. The thickness of the nickel seed layer formed by the electroless nickel plating is 200-500 nm. The nickel seed layer is continuously distributed along the preset conductive pattern and is used as a conductive base layer for subsequent metal thickening treatment.

Images