Grid line electroplating device and method

Abstract

The invention discloses a grid line electroplating device and method, and relates to the technical field of photovoltaics. The grid line electroplating device comprises a cathode conductive module, an anode conductive module, a power supply module and a liquid supply module, a positive electrode of the power supply module is connected with the anode conductive module, a negative electrode of the power supply module is connected with the cathode conductive module, and the cathode conductive module is used for connecting the transparent conductive layer of the battery substrate. The anode conductive module is used for directly facing the grid line groove, the anode conductive module and the grid line groove jointly define a flow channel for electroplating liquid to flow, a liquid inlet and a liquid outlet are formed in the anode conductive module, and the liquid supply module is communicated with the liquid inlet and the liquid outlet and used for enabling the electroplating liquid to circularly flow in the flow channel. When the grid line electroplating device provided by the invention is used for electroplating the grid line, the whole battery base body does not need to be immersed in the electroplating liquid, the flowing electroplating liquid is formed in the grid line groove for electroplating, a mask and laser sintering are not needed, and the risk that the transparent conductive layer is damaged is reduced.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and more specifically, to a grid line electroplating apparatus and method. Background Technology

[0002] Existing heterojunction solar cells typically fabricate their grid lines using methods such as mask plating, laser transfer, inkjet printing, or traditional electroplating. However, these methods all have certain drawbacks: mask plating can lead to mask contamination of the transparent conductive layer and damage to the transparent conductive film during demolding, while also being costly; laser transfer, which involves laser-induced transfer of copper paste, suffers from a low grid line aspect ratio (less than 0.3) and high resistivity (greater than 3 μΩ·cm); traditional electroplating methods require immersing the entire cell substrate in the plating solution, using the entire surface of the substrate as a cathode in conjunction with a parallel flow field for plating, resulting in a complex process. Summary of the Invention

[0003] The purpose of this application is to provide a grid line electroplating apparatus and method that eliminates the need to immerse the entire battery substrate in the electroplating solution, eliminates the need for laser sintering, eliminates the need for a mask, and minimizes damage to the transparent conductive layer.

[0004] The embodiments of this application can be implemented as follows: In a first aspect, this application provides a grid line electroplating apparatus for electroplating grid lines on a battery substrate. The battery substrate includes a transparent conductive layer and grid line grooves formed in the transparent conductive layer. The grid line electroplating apparatus includes a cathode conductive module, an anode conductive module, a power supply module, and a liquid supply module. The positive terminal of the power supply module is connected to the anode conductive module, and the negative terminal of the power supply module is connected to the cathode conductive module. The cathode conductive module is used to connect to the transparent conductive layer of the battery substrate. The anode conductive module is used to face the grid line grooves and together with the grid line grooves to form a flow channel for the electroplating solution to flow. The anode conductive module has an inlet and an outlet. The liquid supply module is connected to the inlet and outlet and is used to circulate the electroplating solution within the flow channel.

[0005] In an optional embodiment, the grid line electroplating apparatus further includes a base, and both the cathode conductive module and the anode conductive module are disposed on the base. The side of the cathode conductive module facing away from the base is used to abut against the transparent conductive layer of the battery substrate, and the side of the anode conductive module facing away from the base is used to form a flow channel with the bottom of the grid line groove spaced apart. The liquid inlet and liquid outlet both penetrate the anode conductive module and the base.

[0006] In an optional embodiment, a mating groove corresponding to the pattern of the grid groove is provided on the base, the anode conductive module is disposed at the bottom of the mating groove, and the cathode conductive module is disposed outside the mating groove.

[0007] In an optional embodiment, the anode conductive module includes multiple anode conductive parts, each anode conductive part being used to face a portion of the grid wire grooves, and a partition is provided between two adjacent anode conductive parts; the grid wire electroplating device includes multiple power modules, and each anode conductive part is electrically connected to the positive electrode of a power module.

[0008] In an optional embodiment, the grid line electroplating apparatus further includes a grid line detection module for detecting the thickness of the deposited metal layer in each grid line groove corresponding to each anode conductive part.

[0009] In an optional implementation, the grid detection module includes multiple infrared probes.

[0010] In an optional embodiment, the liquid supply module includes a liquid storage tank, an inlet pipe, and an outlet pipe. The liquid storage tank is used to store electroplating liquid. The two ends of the inlet pipe are connected to the inlet and the liquid storage tank, respectively. The two ends of the outlet pipe are connected to the outlet and the liquid storage tank, respectively. A pump body is installed on the inlet pipe.

[0011] In an optional embodiment, a sealing insulating strip is provided on the side of the cathode conductive module near the anode conductive module. The sealing insulating strip is used to prevent the electroplating solution from contacting the cathode conductive module.

[0012] In an optional embodiment, the cathode conductive module is provided with multiple vacuum adsorption holes, which are used to adsorb the battery substrate onto the surface of the cathode conductive module.

[0013] Secondly, this application provides a gate line electroplating method, using the gate line electroplating apparatus of any of the foregoing embodiments, the gate line electroplating method comprising: Obtain a battery substrate, which includes a transparent conductive layer and grid grooves formed in the transparent conductive layer; The cathode conductive module of the grid line electroplating device is connected to the transparent conductive layer, and the anode conductive module is directly opposite the grid line groove and together with the grid line groove forms a flow channel for the electroplating solution to flow. The electroplating solution is circulated within the flow channel by the liquid supply module, and an electric field is generated within the flow channel by the power supply module to electroplat grid lines in the grid line groove.

[0014] In an optional embodiment, the gate wire electroplating method further includes: The thickness of the metal layer at multiple locations in the grid slot is obtained, and the electric field intensity at each location of the flow channel is adjusted independently according to the thickness of the metal layer at each location.

[0015] The beneficial effects of the grid line electroplating apparatus and method provided in this application include: This application provides a grid line electroplating apparatus for electroplating grid lines on a battery substrate. The battery substrate includes a transparent conductive layer and grid line grooves formed in the transparent conductive layer. The grid line electroplating apparatus includes a cathode conductive module, an anode conductive module, a power supply module, and a liquid supply module. The positive terminal of the power supply module is connected to the anode conductive module, and the negative terminal of the power supply module is connected to the cathode conductive module. The cathode conductive module is used to connect to the transparent conductive layer of the battery substrate. The anode conductive module is positioned opposite the grid line grooves and together with the grid line grooves forms a flow channel for the electroplating solution to flow. The anode conductive module has an inlet and an outlet, and the liquid supply module is connected to the inlet and outlet to circulate the electroplating solution within the flow channel. When using the grid line electroplating apparatus of this application, the anode conductive module is positioned opposite the grid line grooves, thereby sealing the grid line grooves and forming a flow channel. The liquid supply module allows the electroplating solution to flow within the flow channel without flowing to other areas of the battery substrate. The power module enables a potential difference to be formed between the transparent conductive layer and the anode conductive module, i.e., an electric field is created within the flow channel. Metal cations in the electroplating solution can then deposit within the grid grooves, forming metal grid lines. Therefore, using the grid line electroplating apparatus provided in this application eliminates the need to immerse the entire battery substrate in the electroplating solution. Instead, a flowing electroplating solution is formed within the grid grooves, and the electroplating process can be controlled by adjusting the voltage and flow rate, resulting in high process efficiency. By using the grid line electroplating apparatus, existing grid line fabrication methods are replaced, eliminating the need for masks and laser sintering, thus reducing the risk of damage to the transparent conductive layer.

[0016] The grid line electroplating method provided in this application is implemented using the above-mentioned grid line electroplating apparatus, which has the advantages of high process efficiency and low risk of damage to the transparent conductive layer. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the battery substrate in one embodiment of this application; Figure 2 This is a schematic diagram of a grid line electroplating apparatus in one embodiment of this application; Figure 3 This is a schematic diagram of the battery substrate and grid line electroplating apparatus during the electroplating process in one embodiment of this application; Figure 4 This is a flowchart of a grid line electroplating method in one embodiment of this application.

[0019] Icons: 100-Battery substrate; 110-Transparent conductive layer; 120-Grid groove; 130-Flow channel; 200-Base; 300-Cathode conductive module; 310-Vacuum adsorption hole; 320-Sealing insulating strip; 400-Anode conductive module; 401-Anode conductive part; 402-Separator; 410-Liquid inlet; 420-Liquid outlet; 500-Infrared probe; 600-Reservoir; 610-Liquid inlet pipe; 611-Pump body; 620-Liquid outlet pipe; 700-Power module. Detailed Implementation

[0020] 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 embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of this application, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0024] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0025] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0026] Currently, the common processes for fabricating grid lines on heterojunction solar cells include laser transfer and mask electroplating. These methods are prone to damaging the transparent conductive layer or require additional masks, leading to low product yield, complex processes, and high material costs. Therefore, this application provides a grid line electroplating apparatus that uses a novel method to electroplat grid lines in grid line trenches. This eliminates the need to immerse the battery substrate in the electroplating solution, avoids laser sintering, minimizes damage to the transparent conductive layer, and eliminates the need for mask materials.

[0027] Figure 1 This is a schematic diagram of the battery substrate 100 in one embodiment of this application; Figure 2 This is a schematic diagram of a grid line electroplating apparatus in one embodiment of this application; Figure 3 This is a schematic diagram of the battery substrate 100 and the grid line electroplating apparatus during the electroplating process in one embodiment of this application. Figures 1 to 3 As shown, the grid line electroplating apparatus provided in this application embodiment is used to electroplat grid lines on a battery substrate 100, specifically for fabricating grid lines for a heterojunction battery. The heterojunction battery includes a battery substrate 100 and grid lines (not shown in the figure). The battery substrate 100 includes a silicon substrate, an intrinsic silicon layer, a p-type doped silicon layer, an n-type doped silicon layer, and a transparent conductive layer 110. Two intrinsic silicon layers are respectively disposed on the front and back sides of the silicon substrate. The p-type doped silicon layer and the n-type doped silicon layer are respectively disposed on the intrinsic silicon layers on the front and back sides. Two transparent conductive layers 110 are respectively disposed on the surfaces of the p-type doped silicon layer and the n-type doped silicon layer. The battery substrate 100 with the transparent conductive layer 110 is also referred to as a blue film. The specific structure of the heterojunction battery can be referred to in the prior art, and will not be described in detail here.

[0028] In this embodiment, a grid groove 120 is formed on the battery substrate 100 at the position corresponding to the grid line, and the grid line needs to be electroplated in the grid groove 120 to form the grid line. Figure 1 This is for illustrative purposes only and does not represent the actual ratio of the width of the grid groove 120 to the size of the battery substrate 100; in other embodiments, the pattern of the grid groove 120 may be other shapes.

[0029] The grid line electroplating apparatus provided in this application includes a base 200, a cathode conductive module 300, an anode conductive module 400, a power supply module 700, and a liquid supply module. Both the cathode conductive module 300 and the anode conductive module 400 are disposed on the base 200. The positive terminal of the power supply module 700 is connected to the anode conductive module 400, and the negative terminal of the power supply module 700 is connected to the cathode conductive module 300. The cathode conductive module 300 is used to connect to the transparent conductive layer 110 of the battery substrate 100. The anode conductive module 400 is positioned opposite the grid line groove 120 and together with the grid line groove 120 forms a flow channel 130 for the electroplating solution to circulate. The anode conductive module 400 has an inlet 410 and an outlet 420. The liquid supply module is connected to the inlet 410 and the outlet 420, and is used to circulate the electroplating solution within the flow channel 130.

[0030] In this embodiment, the side of the cathode conductive module 300 facing away from the base 200 is used to abut against the transparent conductive layer 110 of the battery substrate 100. The side of the anode conductive module 400 facing away from the base 200 is used to form a flow channel 130 with the bottom of the grid groove 120 spaced apart. The inlet 410 and the outlet 420 both penetrate the anode conductive module 400 and the base 200, so that the electroplating solution can flow from the back side of the base 200 (the side away from the battery substrate 100) into the flow channel 130, then flow along the flow channel 130, and finally flow out of the back side of the base 200 through the outlet 420. In this embodiment, the pattern of the anode conductive module 400 corresponds to that of the grid groove 120, so it can just cover the opening of the grid groove 120, thereby forming the flow channel 130. The line width of the anode conductive module 400 can be equal to the width of the grid groove 120, or slightly larger than the width of the grid groove 120.

[0031] In this embodiment, the grid line electroplating apparatus has one liquid inlet 410, located in the center of the base 200; multiple liquid outlets 420 are arranged around the liquid inlet 410, with the outlets 420 closer to the edge of the base 200 relative to the liquid inlet 410. During the electroplating process, the outlets 420 are closer to the edge of the battery substrate 100 than the liquid inlet 410, allowing the electroplating solution flowing into the flow channel 130 to diffuse in all directions, which is beneficial to the uniformity of electroplating and reduces the difference in grid line thickness at different locations.

[0032] Optionally, in this embodiment, the sum of the areas of all outlets 420 is less than the area of ​​inlet 410, so that the electroplating solution can quickly fill the channel 130 when injected into it, thereby improving process efficiency.

[0033] like Figure 3As shown, the height of the anode conductive module 400 on the base 200 is lower than that of the cathode conductive module 300. It can be understood that the side of the cathode conductive module 300 facing away from the base 200 needs to be attached to the transparent conductive layer 110, while the anode conductive module 400 needs to be further away from the spatial plane containing the outer surface of the transparent conductive layer 110 than the cathode conductive module 300, so that the ultimately deposited grid lines can extend out of the grid line groove 120, i.e., the grid lines protrude from the outer surface of the transparent conductive layer 110. In this embodiment, the base 200 has a mating groove corresponding to the pattern of the grid line groove 120. The anode conductive module 400 is disposed at the bottom of the mating groove, and the cathode conductive module 300 is disposed outside the mating groove, thus making the height of the anode conductive module 400 on the base 200 lower than that of the cathode conductive module 300. With this arrangement, when the opening of the mating groove is aligned with the opening of the grid line groove 120, the flow channel 130 is formed in the space enclosed by the grid line groove 120 and the mating groove.

[0034] It is understandable that if the electroplating solution comes into contact with the cathode conductive module 300, it will cause the deposition of grid line material on the cathode conductive module 300, and the electroplating solution can also easily seep into the space between the cathode conductive module 300 and the transparent conductive layer 110, thereby contaminating the surface of the transparent conductive layer 110. Therefore, in this embodiment, a sealing insulating strip 320 is provided on the side of the cathode conductive module 300 near the anode conductive module 400 (that is, the side near the mating tank and flow channel 130). The sealing insulating strip 320 is used to prevent the electroplating solution from contacting the cathode conductive module 300. Furthermore, a number of protrusions are provided on the surface of the cathode conductive module 300. The cathode conductive module 300 abuts against the transparent conductive layer 110 through the protrusions. The spaces between the protrusions are filled with a hydrophobic material to reduce capillary effect, which can also prevent the electroplating solution from seeping into the space between the cathode conductive module 300 and the transparent conductive layer 110.

[0035] In this embodiment, when the power module 700 outputs voltage, an electric field is formed within the flow channel 130. Within this electric field, the electric field lines extend from the anode conductive module 400 to the inner wall of the grid groove 120. Therefore, metal cations (such as copper) in the electroplating solution are deposited on the inner wall of the grid groove 120, and the metal layer gradually thickens to form grid lines as electroplating progresses. By adjusting the voltage provided by the power module 700, the electric field strength within the flow channel 130 can be controlled, thereby controlling the electroplating rate.

[0036] In this embodiment, the anode conductive module 400 includes multiple anode conductive parts 401, each of which is positioned opposite a portion of the grid line grooves 120. A partition 402, made of insulating material, is provided between adjacent anode conductive parts 401 to achieve electrical isolation between them. The grid line electroplating apparatus includes multiple power modules 700, with each anode conductive part 401 electrically connected to the positive terminal of one power module 700. By providing multiple anode conductive parts 401 and configuring multiple power modules 700 to supply power to each, the potential of different anode conductive parts 401 can be adjusted individually, thus achieving adjustment of the electric field strength at different locations in the flow channel 130. It is understood that due to the different grid line distribution positions, the electroplating deposition rate at different locations in the flow channel 130 may differ. For example, if the electroplating solution concentration is higher upstream of the flow channel 130, then under the same electric field strength, the electroplating deposition rate upstream of the flow channel 130 will be faster, resulting in a thicker grid line. To balance the thickness difference of the gate lines at different locations, the electric field strength at different locations of the flow channel 130 can be adjusted to make the final deposited gate line thickness more uniform. For example, in one specific embodiment, the voltage provided by the power module 700 connected to the anode conductive part 401 downstream of the flow channel 130 is greater than the voltage provided by the power module 700 connected to the anode conductive part 401 upstream of the flow channel 130.

[0037] In this embodiment, the anode conductive module 400 has a total of six anode conductive parts 401, and the grid groove 120 is divided into six parts. The six anode conductive parts 401 correspond to six grid grooves 120. That is, the six anode conductive parts 401 each participate in the electroplating of a grid line, and the six grid lines together form the grid line pattern. This embodiment uses the division of the anode conductive module 400 into six anode conductive parts 401 as an example. In other embodiments, the anode conductive module 400 can be divided into more anode conductive parts 401. The more anode conductive parts 401 there are, the more precise the control of the electroplating rate can be. Combined with real-time monitoring of the grid line thickness and voltage adjustment, a grid line of uniform thickness can be obtained.

[0038] In this embodiment, the grid line electroplating apparatus further includes a grid line detection module, which is used to detect the thickness of the deposited metal layer in each grid line groove 120 corresponding to each anode conductive part 401. By detecting the thickness of the deposited metal layer in real time, a reference can be provided for adjusting the electric field strength in different areas. For example, when the metal layer thickness in a certain grid line groove 120 is relatively thin, the voltage of the power supply module 700 in the corresponding section can be increased to improve the electric field strength and increase the electroplating deposition rate; conversely, when the metal layer thickness in a certain grid line groove 120 is relatively thick, the voltage of the power supply module 700 in the corresponding section can be decreased to reduce the electric field strength and reduce the electroplating deposition rate. By dynamically adjusting the voltage in real time, the electroplating progress in each section can be made consistent, resulting in better uniformity of the final grid line thickness.

[0039] Optionally, the grid line detection module includes multiple infrared probes 500. The infrared probes 500 can be embedded in the base 200 and extend into the flow channel 130 to detect the thickness of the metal layer in the flow channel 130. In each of the multiple grid line slots 120 corresponding to each anode conductive part 401, at least one infrared probe 500 is provided for detection in each grid line slot 120. In other optional embodiments, the grid line detection module may also include multiple laser interferometers to collect the thickness of the metal layer.

[0040] Furthermore, to ensure that the battery substrate 100 adheres tightly to the grid line electroplating device during the electroplating process and to prevent electroplating solution leakage, in this embodiment, the cathode conductive module 300 is provided with multiple vacuum adsorption holes 310. These vacuum adsorption holes 310 are used to adsorb the battery substrate 100 onto the surface of the cathode conductive module 300. This also allows the transparent conductive film to adhere tightly to the cathode conductive module 300, thereby reducing contact resistance. It should be understood that the vacuum adsorption holes 310 should be connected to a vacuum pump (not shown in the figure) to provide the adsorption force.

[0041] Optionally, the materials of the anode conductive part 401 and the cathode conductive module 300 are good conductors, such as metals or alloys of these metals, such as copper, silver, iron, and aluminum, or graphite can be used as the material of the anode conductive part 401 and the cathode conductive module 300.

[0042] Furthermore, the liquid supply module also includes a storage tank 600, an inlet pipe 610, and an outlet pipe 620. The storage tank 600 is used to store the electroplating solution. The two ends of the inlet pipe 610 are connected to the inlet port 410 and the storage tank 600, respectively. The two ends of the outlet pipe 620 are connected to the outlet port 420 and the storage tank 600, respectively. A pump body 611 is installed on the inlet pipe 610. The flow rate of the electroplating solution in the flow channel 130 can be controlled by controlling the power of the pump body 611. Furthermore, concentration detectors can be installed on the inlet pipe 610, the outlet pipe 620, and the storage tank 600 to detect the concentration of metal ions in the electroplating solution. This allows operators to adjust the concentration of the electroplating solution in the storage tank 600 according to concentration changes, ensuring the electroplating effect.

[0043] Figure 4 This is a flowchart of a gate line electroplating method in one embodiment of this application. Figure 4 As shown in the embodiments of this application, a gate line electroplating method is also provided, including: Step S100: Obtain battery substrate 100, which includes a transparent conductive layer 110 and grid grooves 120 formed in the transparent conductive layer 110.

[0044] Optionally, the grid groove 120 is fabricated using a laser grooving process. In one specific embodiment, an ultraviolet picosecond laser with a wavelength of 355 nm, a pulse width of 10 ps, ​​and an energy of 0.8 J / cm² is used. 2 Alternatively, a vacuum plasma cleaner can be used to activate the transparent conductive layer 110. The plasma used is O2 plasma with a power of 300W and an activation time of 120s.

[0045] In step S200, the cathode conductive module 300 of the grid line electroplating device is connected to the transparent conductive layer 110, and the anode conductive module 400 is directly opposite the grid line groove 120 and together with the grid line groove 120 forms a flow channel 130 for the electroplating solution to flow.

[0046] Optionally, the battery substrate 100 is adsorbed onto the cathode conductive module 300 using the vacuum adsorption hole 310, with a vacuum negative pressure of -5±0.2kPa.

[0047] In step S300, the electroplating solution is circulated in the flow channel 130 by the liquid supply module, and an electric field is formed in the flow channel 130 by the power supply module 700 to electroplat grid lines in the grid line groove 120.

[0048] In this embodiment, the pump body 611 is turned on, allowing the electroplating solution in the storage tank 600 to enter the flow channel 130 through the inlet pipe 610 and the inlet port 410. The electroplating solution is transported along the flow channel 130 and returns to the storage tank 600 through the outlet port 420 and the outlet pipe 620, forming a cycle. Optionally, the electroplating solution formula is CuSO4·5H2O: 40g / L; H2SO4: 100g / L; PEG-6000: 500ppm; Cl - 50ppm. Optionally, the electroplating solution temperature is 20℃~30℃, for example, 20±5℃. Optionally, the inlet flow rate is 0.8m / s.

[0049] In this embodiment, the gate line electroplating method further includes: obtaining the metal layer thickness at multiple locations in the gate line groove 120, and independently adjusting the electric field intensity at each location of the flow channel 130 according to the metal layer thickness at each location. The gate line thickness at multiple locations in the gate line groove 120 can be obtained by the infrared probe 500 of the gate line detection module. By obtaining the metal layer thickness at different locations, the progress of gate line electroplating can be determined and the gate line morphology can be predicted. Due to positional differences, the electroplating rate in the gate line groove 120 at different locations may differ. By independently adjusting the electric field intensity at each location of the flow channel 130, the difference in electroplating rate caused by positional differences can be eliminated as much as possible, thereby resulting in a gate line with uniform thickness. For example, when the metal layer thickness in a certain section of the gate line groove 120 is relatively thick, the voltage of the power supply module 700 in the corresponding section can be reduced to decrease the electric field intensity and reduce the electroplating deposition rate. By dynamically adjusting the voltage in real time, the electroplating progress area of ​​each section can be made consistent, resulting in a gate line with better uniformity in thickness.

[0050] In one specific implementation, it can be controlled in the following manner: (1) Initial stage of electroplating (0s~30s): Current density over the entire area is 6A / dm 2 The inlet has a flow rate of 0.8 m / s and the grid detection module monitors the metal layer thickness in real time.

[0051] (2) Mid-term of electroplating (30s~180s): Based on the metal layer thickness detection results, the current density at different positions is adjusted by the power module 700. For example, the current density of the flow channel 130 near the edge of the battery substrate 100 is increased by 7%; the current density of the flow channel 130 in the central area is decreased by 4%.

[0052] (3) Later stage of electroplating (180s~200s): The working mode of power module 700 is switched to pulse mode, with a duty cycle of t on / t off =5ms / 100ms, current density 4A / dm 2 Voltage fluctuation < ±5mV.

[0053] After electroplating, grid lines of sufficient height (thickness) are formed in the grid line groove 120. Then, the battery substrate 100 with the grid lines can be sprayed with deionized water at a pressure of 0.2 MPa, where the resistivity of the deionized water is ≥18 MΩ·cm. Afterward, nitrogen gas is used for drying, with a nitrogen gas velocity of 30 m / s and a temperature of 40°C.

[0054] After cleaning and drying, the battery cells can be annealed at a temperature of 200°C under a nitrogen atmosphere for 10 minutes at a heating rate of 5°C / min.

[0055] After annealing, the battery can be tested online, including using a white light interferometer to detect the grid line height, with a pass standard of 4.0±0.4μm; using a four-probe surface scan to detect the resistance uniformity, with a pass standard of standard deviation <1.5%; and using a tape peel test (3M 600) to detect the adhesion, with a pass standard of no copper layer peeling.

[0056] The table below shows a test comparison of traditional mask electroplating, existing laser transfer technology and the gate line electroplating process provided in the embodiments of this application.

[0057]

[0058] The comparison in the table above shows that the grid lines obtained using the grid line electroplating process provided in this application have better uniformity, and the standard deviation of grid line height is reduced by 79% compared to the traditional mask electroplating process. Meanwhile, the grid lines produced by the electroplating process in this application have better electrical performance, with grid line resistance distribution uniformity >97%; the product defect rate is <0.1%, far lower than the industry average of 8%. Furthermore, the heterojunction cell using the grid line electroplating process provided in this application shows a 0.25% improvement in cell efficiency.

[0059] In summary, this application provides a grid line electroplating apparatus for electroplating grid lines on a battery substrate 100. The battery substrate 100 includes a transparent conductive layer 110 and grid line grooves 120 formed in the transparent conductive layer 110. The grid line electroplating apparatus includes a cathode conductive module 300, an anode conductive module 400, a power supply module 700, and a liquid supply module. The positive terminal of the power supply module 700 is connected to the anode conductive module 400, and the negative terminal of the power supply module 700 is connected to the cathode conductive module 300. The cathode conductive module 300 is used to connect to the transparent conductive layer 110 of the battery substrate 100. The anode conductive module 400 is positioned opposite the grid line grooves 120 and together with the grid line grooves 120 forms a flow channel 130 for the electroplating solution to flow. The anode conductive module 400 has an inlet 410 and an outlet 420. The liquid supply module is connected to the inlet 410 and the outlet 420 and is used to circulate the electroplating solution within the flow channel 130. When using the grid line electroplating apparatus of this application, the anode conductive module 400 faces the grid line groove 120, thereby sealing the grid line groove 120 and forming a flow channel 130. The electroplating solution can flow in the flow channel 130 through the liquid supply module, without flowing to other areas of the battery substrate 100. The power module 700 enables a potential difference to be formed between the transparent conductive layer 110 and the anode conductive module 400, i.e., an electric field is formed within the flow channel 130, allowing metal cations in the electroplating solution to deposit within the grid line groove 120, thereby forming metal grid lines. Therefore, using the grid line electroplating apparatus provided in this application to electroplat grid lines eliminates the need to immerse the entire battery substrate 100 in the electroplating solution; instead, a flowing electroplating solution is formed within the grid line groove 120. The electroplating process of the grid lines can be controlled by adjusting the voltage and flow rate, resulting in high process efficiency. By using a grid line electroplating device to electroplat the grid lines, the existing grid line manufacturing method is replaced. This eliminates the need for masks and laser sintering, reducing the risk of damage to the transparent conductive layer 110.

[0060] The grid line electroplating method provided in this application is implemented using the above-mentioned grid line electroplating apparatus, which has the advantages of high process efficiency and low risk of damage to the transparent conductive layer 110.

[0061] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A grid line electroplating apparatus for electroplating grid lines on a battery substrate, the battery substrate comprising a transparent conductive layer and grid line grooves formed in the transparent conductive layer, characterized in that, The grid line electroplating device includes a cathode conductive module, an anode conductive module, a power supply module, and a liquid supply module. The positive terminal of the power supply module is connected to the anode conductive module, and the negative terminal of the power supply module is connected to the cathode conductive module. The cathode conductive module is used to connect to the transparent conductive layer of the battery substrate. The anode conductive module is positioned opposite the grid line groove and together with the grid line groove forms a flow channel for the electroplating solution to flow. The anode conductive module has an inlet and an outlet. The liquid supply module is connected to the inlet and the outlet and is used to circulate the electroplating solution within the flow channel.

2. The grid wire electroplating apparatus according to claim 1, characterized in that, The grid line electroplating device further includes a base, and the cathode conductive module and the anode conductive module are both disposed on the base. The side of the cathode conductive module facing away from the base is used to abut against the transparent conductive layer of the battery substrate. The side of the anode conductive module facing away from the base is used to form the flow channel by being spaced apart from the bottom of the grid line groove. The liquid inlet and the liquid outlet both penetrate the anode conductive module and the base.

3. The grid wire electroplating apparatus according to claim 2, characterized in that, The base has a mating groove corresponding to the pattern of the grid groove. The anode conductive module is disposed at the bottom of the mating groove, and the cathode conductive module is disposed outside the mating groove.

4. The grid wire electroplating apparatus according to claim 1, characterized in that, The anode conductive module includes multiple anode conductive parts, each of which is respectively used to face a portion of the grid line grooves, and a partition is provided between two adjacent anode conductive parts; the grid line electroplating device includes multiple power modules, and each anode conductive part is electrically connected to the positive electrode of one of the power modules.

5. The grid line electroplating apparatus according to claim 4, characterized in that, The grid line electroplating apparatus further includes a grid line detection module for detecting the thickness of the deposited metal layer in each grid line groove corresponding to each of the anode conductive parts.

6. The grid line electroplating apparatus according to claim 5, characterized in that, The grid detection module includes multiple infrared probes.

7. The grid wire electroplating apparatus according to claim 1, characterized in that, The liquid supply module includes a liquid storage tank, an inlet pipe, and an outlet pipe. The liquid storage tank is used to store the electroplating solution. The two ends of the inlet pipe are respectively connected to the inlet and the liquid storage tank. The two ends of the outlet pipe are respectively connected to the outlet and the liquid storage tank. A pump body is installed on the inlet pipe.

8. The grid line electroplating apparatus according to claim 1, characterized in that, A sealing and insulating strip is provided on the side of the cathode conductive module near the anode conductive module. The sealing and insulating strip is used to prevent the electroplating solution from contacting the cathode conductive module.

9. The grid wire electroplating apparatus according to claim 1, characterized in that, The cathode conductive module has multiple vacuum adsorption holes, which are used to adsorb the battery substrate onto the surface of the cathode conductive module.

10. A method for electroplating grid lines, characterized in that, Using the grid line electroplating apparatus according to any one of claims 1-9, the grid line electroplating method comprises: Obtain a battery substrate, the battery substrate comprising a transparent conductive layer and grid grooves formed in the transparent conductive layer; The cathode conductive module of the grid line electroplating device is connected to the transparent conductive layer, and the anode conductive module is directly opposite the grid line groove and together with the grid line groove forms a flow channel for the electroplating solution to flow. The electroplating solution is circulated within the flow channel by the liquid supply module, and an electric field is generated within the flow channel by the power supply module to electroplat grid lines in the grid line groove.

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