Etching equipment and etching method

Abstract

The invention provides etching equipment and an etching method, relates to the technical field of photovoltaics, and aims to solve the technical problem that a photovoltaic cell manufacturing process is tedious. The etching equipment comprises a conveying device and a liquid supply device, the liquid supply device comprises a first liquid supply part and a second liquid supply part which are opposite to each other, and the first liquid supply part and the second liquid supply part are arranged at an interval to form a passage for a photovoltaic cell to pass through; the conveying device is used for driving the photovoltaic cells to pass through the passage; the end face, facing the second liquid supply part, of the first liquid supply part is provided with a first liquid outlet, and the end face, facing the first liquid supply part, of the second liquid supply part is provided with a second liquid outlet. In the first direction, the length of the second liquid outlet is larger than or equal to the preset length, and the length of the first liquid outlet is smaller than the preset length. The preset length refers to the length of the photovoltaic battery piece in the first direction, and the first direction is perpendicular to the conveying direction of the conveying device. The etching equipment is used for asynchronous etching of two surfaces of a photovoltaic cell, and integration of single equipment can be realized while the process flow is reduced.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to an etching device and an etching method. Background Art

[0002] The statements in this section merely provide background art related to the present invention and do not necessarily constitute prior art.

[0003] In the field of photovoltaic cell manufacturing, the preparation of back-contact cells requires forming different morphologies on the front and back of the substrate. For example, a pyramid-shaped velvet surface is formed on the front of the substrate to increase the light absorption rate of the cell, while a tower-base-shaped polished surface is formed on the back of the substrate to provide a reaction interface for the subsequent deposition process of forming the P and N regions.

[0004] In the related art, a wet etching process is used to form a velvet surface and a polished surface on a substrate respectively. However, wet etching is non-selective etching for the substrate. Therefore, forming the double-sided morphology of the above-mentioned substrate requires at least several basic process steps such as velvet preparation, mask deposition, polishing, and mask removal, and the process is cumbersome. Summary of the invention

[0005] The purpose of the present invention is to provide an etching device and an etching method to solve the technical problem of complicated photovoltaic cell manufacturing process.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides an etching device for simultaneously etching two surfaces of a photovoltaic cell, the etching device comprising a conveying device and a liquid supply device, the liquid supply device comprising a first liquid supply member and a second liquid supply member opposite to each other, the first liquid supply member and the second liquid supply member being arranged at intervals to form a passage for the photovoltaic cell to pass through;

[0008] The conveying device is used to drive the photovoltaic cell sheet to pass through the passage;

[0009] The end surface of the first liquid supply member facing the second liquid supply member has a first liquid outlet, and the end surface of the second liquid supply member facing the first liquid supply member has a second liquid outlet;

[0010] In the first direction, the length of the second liquid outlet is greater than or equal to a preset length, and the length of the first liquid outlet is less than the preset length;

[0011] The preset length refers to the length of the photovoltaic cell in a first direction, and the first direction is perpendicular to the conveying direction of the conveying device.

[0012] According to at least one embodiment of the present invention, the conveying device includes a driving device and two rollers drivingly connected to the driving device, and the two rollers are respectively in contact with two sides of the photovoltaic cell sheet.

[0013] According to at least one embodiment of the present invention, the two rollers are respectively located on both sides of the passage, and the diameter of the cross section of the roller increases along the direction from the second liquid supply member to the first liquid supply member;

[0014] The roller abuts against both the side surface of the first liquid supply member and the side surface of the second liquid supply member.

[0015] According to at least one embodiment of the present invention, the first liquid supply member has a cavity for accommodating a first etching liquid, the first liquid outlet is connected to a portion of the cavity close to the bottom wall, and the top wall of the cavity is close to or flush with an end surface of the first liquid supply member facing the second liquid supply member.

[0016] According to at least one embodiment of the present invention, the etching equipment further comprises a first pushing device, and the first pushing device is fluidically connected to the chamber.

[0017] According to at least one embodiment of the present invention, the first liquid supply member further has a first channel connected to the first liquid outlet, and one end of the first channel facing away from the first liquid outlet is connected to the outside of the first liquid supply member.

[0018] According to at least one embodiment of the present invention, the first liquid supply member further comprises a rolling member movably disposed in the first liquid outlet, the rolling member dividing the first liquid outlet into a first part communicating with the cavity and a second part communicating with the first channel.

[0019] According to at least one embodiment of the present invention, a partial surface of the rolling element is flush with or higher than an end surface of the first liquid supply element facing the second liquid supply element; and / or,

[0020] The rolling element is a cylinder.

[0021] According to at least one embodiment of the present invention, a third portion is further formed between the rolling element and the bottom wall of the first liquid outlet, wherein the third portion communicates with the first portion and the second portion.

[0022] According to at least one embodiment of the present invention, there are multiple liquid supply devices, and the multiple liquid supply devices are arranged along the conveying direction of the conveying device;

[0023] The etching device further comprises two slide rails, each of the first liquid supply members is slidably arranged on one of the slide rails, and each of the second liquid supply members is slidably arranged on the other of the slide rails.

[0024] According to at least one embodiment of the present invention, the arrangement density of the plurality of liquid supply devices along the conveying direction is first large and then small.

[0025] According to at least one embodiment of the present invention, in the first direction, the midpoint of the first liquid outlet, the midpoint of the second liquid outlet, and the midpoint of the photovoltaic cell are at the same position.

[0026] In a second aspect, the present invention further provides an etching method, using the etching device described in the first aspect to simultaneously etch two surfaces of a photovoltaic cell, the method comprising:

[0027] Providing the photovoltaic cell sheet in transmission;

[0028] Supplying a second etching liquid on the upper surface of the photovoltaic cell through the second liquid outlet of the second liquid supply member, wherein an extension length of the second etching liquid in the first direction is greater than or equal to the preset length;

[0029] A first etching liquid is supplied to the lower surface of the photovoltaic cell sheet through the first liquid outlet of the first liquid supply member, and an extension length of the first etching liquid in the first direction is less than the preset length.

[0030] According to at least one embodiment of the present invention, the second etching solution and the first etching solution are the same or different etching solutions.

[0031] According to at least one embodiment of the present invention, when the second etching solution and the first etching solution are different etching solutions, the second etching solution is a texturing etching solution, and the first etching solution is a polishing etching solution.

[0032] According to at least one embodiment of the present invention, when supplying the first etching solution to the lower surface of the photovoltaic cell, the method includes:

[0033] Adjusting the liquid supply rate of the first etching solution; and / or improving the wettability of the first etching solution so as to completely etch the lower surface of the photovoltaic cell.

[0034] Among the one or more technical solutions provided in the exemplary embodiments of the present invention, at least one of the following beneficial effects can be achieved.

[0035] The etching device of the exemplary embodiment of the present invention includes a conveying device and a liquid supply device, wherein the conveying device is used to convey the photovoltaic cell forward and pass through the passage between the first liquid supply part and the second liquid supply part of the liquid supply device. On the two opposite end faces of the first liquid supply part and the second liquid supply part, there are respectively a first liquid outlet and a second liquid outlet. When the photovoltaic cell passes through the passage, its two surfaces are coated with the first etching liquid and the second etching liquid respectively, wherein the length of the second liquid outlet is greater than or equal to the preset length of the photovoltaic cell, that is, the second etching liquid is coated within the entire preset length of one surface of the photovoltaic cell, and the second etching liquid can be evenly covered on the surface under the forward conveyance of the photovoltaic cell. The length of the first liquid outlet is less than the preset length, and the first etching liquid can make up for the problem of the edge integrity of the surface of the photovoltaic cell by improving wettability. Through the length difference between the first liquid outlet and the second liquid outlet, the etching of the two surfaces of the photovoltaic cell is carried out simultaneously without interfering with each other. Compared with the prior art, due to the non-selectivity of wet etching, in order to achieve different morphologies on the two surfaces of the photovoltaic cell, at least several basic process steps such as texturing-mask deposition-polishing-mask removal are required. While increasing the number of process steps, the overall process time is greatly prolonged. The etching equipment of the exemplary embodiment of the present invention can realize the integration of a single device while reducing the process flow.

[0036] Furthermore, the etching equipment of the exemplary embodiment of the present invention can maintain the batch processing capacity of the chain wet etching equipment while achieving the stability of the total amount of reactants per unit area with fixed scheduling and replenishment compared to the tank wet etching equipment, and the consumption of reaction chemicals and pure water required to achieve the same effect is less. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings illustrate exemplary embodiments of the present invention and together with the description serve to explain the principles of the present invention, and these drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification;

[0038] Figure 1 is a schematic diagram of the overall structure of an etching device according to an embodiment of the present invention;

[0039] Figure 2 is a front view structural schematic diagram of a liquid supply device according to an embodiment of the present invention;

[0040] Figure 3 is a schematic structural diagram of a liquid supply device in a top view according to an embodiment of the present invention;

[0041] Figure 4 is a schematic diagram of a longitudinal cross-sectional structure of a liquid supply device according to an embodiment of the present invention;

[0042] Figure 5is an isometric structural schematic diagram of a liquid supply device and a photovoltaic cell according to an embodiment of the present invention;

[0043] Figure 6 yes Figure 5 A schematic diagram of the local structure of part A;

[0044] Figure 7 is a schematic side structural view of a liquid supply device according to an embodiment of the present invention;

[0045] Figure 8 yes Figure 7 A schematic diagram of the partial structure of part B;

[0046] Fig. 9 is a partial structural schematic diagram of a liquid supply device according to another embodiment of the present invention;

[0047] Fig.10 4 is a schematic flow chart of an etching method according to an embodiment of the present invention.

[0048] Reference numerals:

[0049] 10. Liquid supply device; 11. First liquid supply member; 111. First liquid outlet; 111a. First part; 111b. Second part; 111c. Third part; 112. Receptacle; 113. First channel; 12. Second liquid supply member; 121. Second liquid outlet;

[0050] 20. Photovoltaic cell; 21. Lower surface; 22. Upper surface;

[0051] 30. roller; 31. rotating shaft;

[0052] 40. Rolling parts. DETAILED DESCRIPTION

[0053] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0054] In the field of photovoltaic cell manufacturing, the two surfaces on the substrate of the back contact photovoltaic cell (BC) need to be prepared with different morphologies. For example, the front side (light-receiving side) needs to form a velvet surface formed by a pyramid-shaped morphology with certain size, height and density specifications to increase the light absorption rate of the front side of the photovoltaic cell; the back side needs to form a polished surface composed of tower-shaped morphologies with certain size and quantity specifications to provide a reaction interface for the subsequent deposition of P and N regions.

[0055] In order to form velvet and polished surfaces on back-contact photovoltaic cells, a wet etching process is used in the relevant technology. The etching equipment in the wet etching process includes two configurations: trough type and chain type. Among them, the trough type wet etching equipment is usually used for batch processing. The photovoltaic cell substrates are loaded in a standard substrate box and then placed in different chemical tanks for processing. The trough type equipment can process multiple substrates at the same time, which is suitable for application scenarios that do not require particularly high production efficiency; the chain type wet etching equipment is a continuous processing system. The photovoltaic cell substrates are moved in one processing tank after another through a conveyor chain, which is suitable for high-yield and highly automated production environments.

[0056] Since wet etching is non-selective to the photovoltaic cell substrate (silicon wafer) itself, neither texturing nor polishing can produce the desired morphology on only one side. In the related technology, under the manufacturing process of mass production equipment of the bonding production line, achieving different morphologies on both sides of the photovoltaic cell substrate requires at least several basic process steps such as texturing-mask deposition-polishing-mask removal, which increases the process steps and prolongs the process time.

[0057] The etching device provided by the exemplary embodiment of the present invention uses a single etching device and two different etching liquid supply parts to perform synchronous etching on the upper and lower surfaces of the photovoltaic cell sheet, respectively, so as to simultaneously achieve different morphologies on both sides. By setting the length of the liquid outlet of one of the two liquid supply parts to be less than the preset length of the photovoltaic cell sheet, the etching liquids on the upper and lower surfaces will not interfere with each other, and the stability of the etching reaction interface on the upper and lower surfaces is maintained, thereby shortening the preparation process of photovoltaic cells with different morphologies on both sides and integrating them into a single device, reducing the consumption of etching liquid while retaining the core batch processing capability of the chain wet etching device.

[0058] Figure 5 is an isometric structural schematic diagram of a liquid supply device and a photovoltaic cell according to an embodiment of the present invention; Figure 7 2 is a schematic diagram of the side view of the liquid supply device according to an embodiment of the present invention. Figure 5 and Figure 7As shown, the etching equipment of an exemplary embodiment of the present invention includes a conveying device and a liquid supply device 10, the liquid supply device 10 includes a first liquid supply member 11 and a second liquid supply member 12 relative to each other, the first liquid supply member 11 and the second liquid supply member 12 are arranged at intervals to form a passage for the photovoltaic cell 20 to pass through; the conveying device is used to drive the photovoltaic cell 20 through the passage; the end surface of the first liquid supply member 11 facing the second liquid supply member 12 has a first liquid outlet 111, and the end surface of the second liquid supply member 12 facing the first liquid supply member 11 has a second liquid outlet 121; in the first direction, the length of the second liquid outlet 121 is greater than or equal to the preset length, and the length of the first liquid outlet 111 is less than the preset length; the preset length refers to the length of the photovoltaic cell 20 in the first direction, and the first direction is perpendicular to the conveying direction of the conveying device.

[0059] In practical applications, a plurality of conveying devices and liquid supply devices 10 are distributed in an array along the conveying direction of the photovoltaic cell 20, such as Figure 3 and Figure 4 As shown, Figure 3 is a schematic structural diagram of a liquid supply device in a top view according to an embodiment of the present invention; Figure 4 1 is a schematic diagram of a longitudinal cross-sectional structure of a liquid supply device according to an embodiment of the present invention. Driven by the conveying device, when the photovoltaic cell 20 passes through the passage, that is, passes through the gap between the first liquid supply member 11 and the second liquid supply member 12 that are arranged opposite to each other, the second etching liquid supplied by the second liquid supply member 12 through the second liquid outlet 121 is coated on the upper surface 22 of the photovoltaic cell 20, and the first etching liquid supplied by the first liquid supply member 11 through the first liquid outlet 111 is coated on the lower surface 21 of the photovoltaic cell 20.

[0060] When the length of the second liquid outlet 121 in the first direction is greater than or equal to the preset length of the photovoltaic cell 20, the second etching liquid is coated on the upper surface 22 of the photovoltaic cell 20 along the first direction, and combined with the forward transmission of the photovoltaic cell 20, the second etching liquid can be evenly coated on the entire upper surface 22. Correspondingly, the length of the first liquid outlet 111 in the first direction is less than the preset length of the photovoltaic cell 20, that is, the edge of the lower surface 21 of the photovoltaic cell 20 is not opposite to the first liquid outlet 111, and the length of the first liquid outlet 111 in the first direction is narrowed, for example, slightly less than the preset length, which can prevent the first etching liquid from rising to the upper surface 22 of the photovoltaic cell 20 through surface tension and avoid interfering with the etching reaction interface of the upper surface 22. Thereby, the etching effects of different morphologies on the upper surface 22 and the lower surface 21 of the photovoltaic cell 20 can be achieved.

[0061] In some embodiments, in the first direction, the midpoint of the first liquid outlet 111, the midpoint of the second liquid outlet 121, and the midpoint of the photovoltaic cell 20 are aligned. That is, the edge of the first liquid outlet 111 in the first direction is at the same distance from the corresponding edge of the photovoltaic cell 20; the edge of the second liquid outlet 121 in the first direction is at the same distance from the corresponding edge of the photovoltaic cell 20. The first etching solution and the second etching solution can be uniformly coated on the lower surface 21 and the upper surface 22 of the photovoltaic cell 20, respectively.

[0062] Exemplarily, the second etching solution and the first etching solution are the same or different etching solutions. When the second etching solution and the first etching solution are different etching solutions, the second etching solution may be a texturing etching solution, and the first etching solution may be a polishing etching solution.

[0063] For example, the second etching solution is an alkaline solution or an acid solution to form a velvet surface on the upper surface 22 of the photovoltaic cell 20, and the first etching solution includes a surfactant, a reaction accelerator / decelerator, a viscosity regulator, a degassing agent, etc. to form a polished surface on the lower surface 21 of the photovoltaic cell 20.

[0064] Since the second etching liquid is on the upper surface 22 of the photovoltaic cell 20, even if the reaction liquid after etching partially diffuses to the lower surface 21 under the influence of gravity, it is difficult to affect the polished surface of the lower surface 21. This is because the reverse texturing process of the polished surface of the photovoltaic cell 20 is very difficult. Specifically, the semi-finished wafer that has been polished has a lower density of surface sites (silicon-oxygen single bonds) that can bind to hydroxide ions on the exposed crystal surface during the texturing process than the original silicon wafer. Therefore, the rate at which the texturing additive combines and completely covers the surface of the silicon wafer decreases rapidly, and the process of forming a uniform velvet surface is relatively more difficult. The first etching liquid is likely to affect the raising process of the upper surface 22 of the photovoltaic cell 20. Therefore, the first etching liquid etches the photovoltaic cell 20 from the bottom, and the first liquid outlet 111 is narrowed, and the second etching liquid etches the photovoltaic cell 20 from the top, so that the first etching liquid is not easy to diffuse from the side of the photovoltaic cell 20 to the upper surface 22 of the photovoltaic cell 20, and thus it is difficult to affect the raising of the photovoltaic cell 20.

[0065] In some embodiments, since the first liquid outlet 111 is narrowed, its length in the first direction is less than the preset length of the photovoltaic cell 20. In order to maintain the etching effect on the edge of the lower surface 21 of the photovoltaic cell 20, there are multiple embodiments that can be implemented.

[0066] For example, the supply rate of the first etching solution may be increased so that the first etching solution can diffuse to the edge of the lower surface 21 after being supplied from the first liquid outlet 111 to the lower surface 21 .

[0067] Exemplarily, the contact area of ​​the solution can also be increased by increasing the wettability of the first etching solution. For example, by adjusting the component content of the surfactant in the first etching solution, the wetting effect of the first etching solution on the solid-liquid interface is greater than that on the gas-liquid interface, that is, the wetting angle of the first etching solution at the contact reaction interface is increased; optionally, the component content of the viscosity control agent in the first etching solution is adjusted to increase the surface tension of the first etching solution and further reduce the wetting angle of the gas-liquid interface; thereby, the first etching solution is supplied from the first liquid outlet 111 to the lower surface 21 and then diffuses to the edge of the lower surface 21 of the photovoltaic cell 20.

[0068] In another optional embodiment, on the etching equipment, a jet nozzle is arranged on both sides of the passage of the liquid supply device 10, and the two jet nozzles are respectively directed toward the edge portions on both sides of the lower surface 21 of the photovoltaic cell 20 in the first direction, and the jets of the jet nozzles are also the first etching liquid. For example, each jet nozzle is connected to a container storing the first etching liquid through a pumping device and corresponding pipelines, so that the first etching liquid can be spread all over the lower surface 21 of the photovoltaic cell 20 to maintain the integrity of the reaction interface.

[0069] Figure 6 yes Figure 5 Schematic diagram of the partial structure of part A. Figure 5 and Figure 6 As shown, in the etching device provided by the exemplary embodiment of the present invention, the conveying device includes a driving device and two rollers 30 drivingly connected to the driving device, and the two rollers 30 are respectively abutted against two sides of the photovoltaic cell 20.

[0070] For example, the driving device can be a motor, which drives the two rollers 30 to rotate through the corresponding rotating shaft 31, and the rotating shaft 31 is arranged on both sides of the photovoltaic cell 20 along the vertical direction. The two rollers 30 abut against the two side surfaces of the photovoltaic cell 20 and drive the photovoltaic cell 20 to move forward along the conveying direction through friction. In this process, the end surface of the first liquid supply member 11 facing the second liquid supply member 12 can also play a role in supporting the photovoltaic cell 20.

[0071] Continue as Figure 5 As shown, the two rollers 30 in the conveying device can be located at any position in the conveying direction, or can be located on both sides of the passage, and the diameter of the cross section of the roller 30 increases along the direction from the second liquid supply part 12 to the first liquid supply part 11; the roller 30 is in contact with the side surface of the first liquid supply part 11 and the side surface of the second liquid supply part 12.

[0072] When the length of the second liquid supply port of the second liquid supply member 12 is greater than the preset length, the side of the second liquid supply member 12, the side of the photovoltaic cell 20 and the side of the first liquid supply member 11 form a gradient structure that narrows inward in sequence. By setting the cross section of the roller 30 to a frustum-shaped structure that is small at the top and large at the bottom, the outer surface of the roller 30 can form abutment with the side of the second liquid supply member 12, the side of the photovoltaic cell 20 and the side of the first liquid supply member 11. On the one hand, the structural form of this roller 30 can convey the photovoltaic cell 20 to move forward; on the other hand, this roller 30 is set on both sides of the passage, that is, on both sides of the first liquid outlet 111 and the second liquid outlet 121, and can achieve physical isolation between the second etching liquid on the upper surface 22 and the first etching liquid on the lower surface 21 at this position, so that the etching of different surfaces of the photovoltaic cell 20 does not interfere with each other.

[0073] Figure 8 yes Figure 7 Schematic diagram of the partial structure of part B. Figure 7 and Figure 8 As shown, the first liquid supply member 11 has a cavity 112 for containing the first etching liquid, the first liquid outlet 111 is connected to the portion of the cavity 112 close to the bottom wall, and the top wall of the cavity 112 is close to or flush with the end surface of the first liquid supply member 11 facing the second liquid supply member 12.

[0074] Since the first liquid outlet 111 of the first liquid supply member 11 provides the first etching liquid for the lower surface 21 of the photovoltaic cell 20 from bottom to top, the influence of gravity may cause the fluctuation of the etching liquid level. The first etching liquid is pre-stored in the cavity 112 by using the principle of the communicating vessel. Since the top wall of the cavity 112 is close to or flush with the end surface of the first liquid supply member 11 facing the second liquid supply member 12, and the first liquid outlet 111 is connected to the position near the bottom of the cavity 112, the liquid level of the first liquid outlet 111 is flush with the liquid level of the cavity 112. When the photovoltaic cell 20 passes through the first liquid outlet 111, a first pushing device connected to the fluid of the cavity 112, such as a peristaltic pump, a gear pump, etc., is used to apply a certain pressure to the liquid in the cavity 112. At this time, the first etching liquid in the first liquid outlet 111 is affected by both surface tension and gravity, and a reaction interface with good contact with the first etching liquid is formed on the lower surface 21 of the photovoltaic cell 20. Based on this, by setting the containing cavity 112, the violent fluctuation of the first etching liquid at the first liquid outlet 111 is reduced, which is beneficial to the formation of a good etching reaction interface.

[0075] Exemplarily, a rolling member 40 is movably disposed in the first liquid outlet 111, and the rolling member 40 is clearance-matched with the first liquid outlet 111. For example, the rolling member 40 is a cylinder. The first etching liquid is pumped out from the gap between the first liquid outlet 111 and the rolling member 40. For example, the liquid level of the first etching liquid is 1 mm to 5 mm higher than the top surface of the first liquid outlet 111.

[0076] Exemplarily, a part of the surface of the rolling member 40 is flush with or higher than the end surface of the first liquid supply member 11 facing the second liquid supply member 12. In this embodiment, on the one hand, the rolling member 40 can supply the first etching liquid in the form of eddy current on the lower surface 21 of the photovoltaic cell 20, which is beneficial to the transportation of the first etching liquid and the discharge of the etching reaction liquid; on the other hand, the rolling member 40 can also serve as a rolling support for the photovoltaic cell 20, thereby facilitating the smooth transportation of the photovoltaic cell 20.

[0077] Fig. 9 FIG. 1 is a partial structural schematic diagram of a liquid supply device according to another embodiment of the present invention. Fig. 9 As shown, the first liquid supply member 11 further has a first channel 113 communicating with the first liquid outlet 111 , and one end of the first channel 113 facing away from the first liquid outlet 111 is communicated with the outside of the first liquid supply member 11 .

[0078] The first channel 113 has one end away from the first liquid outlet 111, extends downward from the first liquid outlet 111 and is connected to the outside of the first liquid supply member 11. Since the density of the etching product formed by the photovoltaic cell 20 and the first etching liquid is greater than the density of the first etching liquid, the etching product will settle under the action of gravity at the first liquid outlet 111, and then be smoothly discharged through the first channel 113, so as to facilitate the supply of new first etching liquid from the first liquid outlet 111 to maintain a good etching reaction interface on the lower surface 21 of the photovoltaic cell 20.

[0079] Continue as Fig. 9 As shown, the first liquid supply member 11 further has a rolling member 40 movably disposed in the first liquid outlet 111 , and the rolling member 40 divides the first liquid outlet 111 into a first portion 111 a communicating with the cavity 112 and a second portion 111 b communicating with the first channel 113 .

[0080] In practical applications, the position where the cavity 112 is connected to the first part 111a of the first liquid outlet 111 is close to the top of the first liquid outlet 111, and the position where the first channel 113 is connected to the second part 111b of the first liquid outlet 111 is close to the bottom of the first liquid outlet 111. The first etching liquid in the cavity 112 enters from the position near the top of the first liquid outlet 111 through the corresponding connecting passage, and is coated on the lower surface 21 of the photovoltaic cell 20 from the top of the first liquid outlet 111 through the rolling member 40. The reactants generated after the etching reaction are driven by the rolling member 40 and under the influence of their own gravity, and are settled to the bottom of the first liquid outlet 111 and discharged out of the first liquid supply member 11 through the first channel 113, thereby realizing the discharge of waste liquid. Based on this, the first liquid outlet 111 is divided into a first part 111a and a second part 111b by the rolling member 40, and the position where the first etching liquid enters the first part 111a is closer to the photovoltaic cell 20, and the position where the second part 111b discharges the etching reactant is far away from the photovoltaic cell 20, so that the first liquid supply member 11 can more smoothly complete the delivery of the first etching liquid and the discharge of the etching reactant.

[0081] In some embodiments, a third portion 111 c is further formed between the rolling element 40 and the bottom wall of the first liquid outlet 111 , wherein the third portion 111 c communicates with the first portion 111 a and the second portion 111 b .

[0082] Since the liquid level at the first liquid outlet 111 may be disturbed at the contact interface when the liquid is first pumped, the excess liquid of the first etching liquid in the first part 111a is discharged from the first channel 113 through the second part 111b via the third part 111c under the rolling element 40, thereby forming a relatively stable liquid level to form a stable etching reaction interface with the photovoltaic cell 20.

[0083] When a portion of the surface of the rolling element 40 is flush with or higher than the end surface of the first liquid supply element 11 facing the second liquid supply element 12 , the rolling element 40 can also assist in the transmission of the photovoltaic cell 20 .

[0084] It is understandable that the structure of the second liquid supply member 12 can be completely the same as that of the first liquid supply member 11. The structure of the second liquid supply member 12 can also be different from that of the first liquid supply member 11. For example, the second liquid outlet 121 of the second liquid supply member 12 is a slit formed on the second liquid supply member 12, and the second etching liquid is pumped to the slit by a pump arranged outside the second liquid supply member 12, and is supplied from the opening of the second liquid supply member 12 toward the end face of the first liquid supply member 11 to the upper surface 22 of the photovoltaic cell 20 to perform an etching reaction to form a velvet surface.

[0085] like Figure 3 and Figure 4As shown, there are multiple liquid supply devices 10, and the multiple liquid supply devices 10 are arranged along the conveying direction of the conveying device; the etching equipment also includes two slide rails, each first liquid supply component 11 is slidably arranged on one slide rail, and each second liquid supply component 12 is slidably arranged on the other slide rail.

[0086] Since the arrangement density of the liquid supply device 10 will affect the etching accuracy of the photovoltaic cell 20, in order to achieve the regulation of the etching of the photovoltaic cell 20, the position of the liquid supply device 10 composed of the first liquid supply part 11 and the second liquid supply part 12 in the conveying direction is controlled by the controller to control the etching reaction time. For example, the arrangement density of the liquid supply device 10 along the conveying direction is first large and then small, and then the supply frequency of the first etching solution and the second etching solution in the early, middle and late stages of the etching reaction is adjusted, thereby controlling the size, density, etc. of the morphology of the upper surface 22 and the lower surface 21 of the photovoltaic cell 20 to maintain the stability of the etching effect.

[0087] In order to maintain the stability of the movement of the first liquid supply member 11 and the second liquid supply member 12, two sliders are respectively arranged on the two sides of the first liquid supply member 11 away from the second liquid supply member 12, and the two sliders are respectively slidably arranged on two parallel slide rails; the second liquid supply member 12 is slidably arranged on the other two parallel slide rails, and two sliders are respectively arranged on the two sides of the second liquid supply member 12 away from the first liquid supply member 11, and the two sliders are respectively slidably arranged on the other two parallel slide rails. It can be understood that the above four slide rails all extend along the conveying direction of the photovoltaic cell 20.

[0088] Figure 1 is a schematic diagram of the overall structure of an etching device according to an embodiment of the present invention; Figure 2 2 is a schematic diagram of the front view of the liquid supply device according to an embodiment of the present invention. Figure 1 and Figure 2 As shown, a single etching device has four rows of liquid supply device 10 arrays along the first direction, which means that four photovoltaic cells 20 can be processed in parallel at the same time to improve production efficiency.

[0089] The exemplary embodiment of the present invention further provides an etching method, which uses the etching equipment of the above embodiment to etch two surfaces of the photovoltaic cell 20 simultaneously.

[0090] Fig.10 Schematic diagram of the etching method according to an embodiment of the present invention. Fig.10 As shown, the etching method comprises the following steps:

[0091] Step 1001: provide a photovoltaic cell 20 being transported.

[0092] The photovoltaic cell 20 to be processed is placed in a basket fixture and passes through the loading area, the pre-cleaning area, and then enters the texturing-polishing area.

[0093] Step 1002: supply a second etching liquid to the upper surface 22 of the photovoltaic cell 20 through the second liquid outlet 121 of the second liquid supply member 12, and the extension length of the second etching liquid in the first direction is greater than or equal to a preset length; supply a first etching liquid to the lower surface 21 of the photovoltaic cell 20 through the first liquid outlet 111 of the first liquid supply member 11, and the extension length of the first etching liquid in the first direction is less than a preset length.

[0094] The photovoltaic cell 20 to be processed is transferred to the liquid supply device 10 array via the roller 30 of the transmission device. When passing through the passage between the first liquid supply component 11 and the second liquid supply component 12 in the liquid supply device 10, the second liquid supply component 12 coats the second etching liquid for texturing on the upper surface 22 of the photovoltaic cell 20 and controls the corresponding temperature. At the same time, the first liquid supply component 11 coats the first etching liquid for polishing on the lower surface 21 of the photovoltaic cell 20 and controls the corresponding temperature, thereby achieving a double-sided asynchronous etching effect on the upper surface 22 and the lower surface 21 of the photovoltaic cell 20.

[0095] After the photovoltaic cell 20 has been etched by the array of the liquid supply device 10 , the photovoltaic cell 20 may enter a post-processing step, such as post-cleaning, dehydration and drying.

[0096] When the first etching liquid is supplied to the lower surface 21 of the photovoltaic cell 20, since the length of the first liquid outlet 111 of the first liquid supply member 11 is smaller than the preset length of the photovoltaic cell 20, in order to maintain the etching integrity of the entire lower surface 21 of the photovoltaic cell 20, the liquid supply rate of the first etching liquid can be increased, or the wettability of the first etching liquid can be increased so that the first etching liquid can diffuse to the edge of the lower surface 21 after being supplied from the first liquid outlet 111 to the lower surface 21.

[0097] like Figure 7 and Figure 8 As shown, when the photovoltaic cell 20 passes through the first liquid outlet 111, a first pushing device connected to the fluid of the cavity 112 is used, such as a peristaltic pump, a gear pump, etc., to apply a certain pressure to the liquid in the cavity 112. At this time, the first etching liquid in the first liquid outlet 111 is affected by both surface tension and gravity, and a reaction interface with good contact with the first etching liquid is formed on the lower surface 21 of the photovoltaic cell 20. The liquid supply rate of the first etching liquid can be increased by increasing the pressure of the first pushing device; otherwise, the liquid supply rate of the first etching liquid can be reduced.

[0098] The technical advantages of the above etching method over the prior art are the same as the advantages of the above etching equipment, which will not be repeated here.

[0099] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. An etching device, characterized in that: Used for etching two surfaces of a photovoltaic cell simultaneously, the etching device comprises a conveying device and a liquid supply device, the liquid supply device comprises a first liquid supply member and a second liquid supply member opposite to each other, the first liquid supply member and the second liquid supply member are arranged at intervals to form a passage for the photovoltaic cell to pass through; The conveying device is used to drive the photovoltaic cell sheet to pass through the passage; The end surface of the first liquid supply member facing the second liquid supply member has a first liquid outlet, and the end surface of the second liquid supply member facing the first liquid supply member has a second liquid outlet; In the first direction, the length of the second liquid outlet is greater than or equal to a preset length, and the length of the first liquid outlet is less than the preset length; The preset length refers to the length of the photovoltaic cell in a first direction, and the first direction is perpendicular to the conveying direction of the conveying device.

2. The etching device according to claim 1, characterized in that: The conveying device comprises a driving device and two rollers drivingly connected to the driving device, and the two rollers are respectively in contact with two sides of the photovoltaic cell sheet.

3. The etching device according to claim 2, characterized in that: The two rollers are respectively located on both sides of the passage, and the diameter of the cross section of the roller increases along the direction from the second liquid supply member to the first liquid supply member; The roller abuts against both the side surface of the first liquid supply member and the side surface of the second liquid supply member.

4. The etching device according to claim 1, characterized in that: The first liquid supply member has a cavity for containing a first etching liquid, the first liquid outlet is communicated with a portion of the cavity close to the bottom wall, and the top wall of the cavity is close to or flush with an end surface of the first liquid supply member facing the second liquid supply member; Preferably, the etching equipment further comprises a first pushing device, and the first pushing device is fluidically connected to the chamber.

5. The etching device according to claim 4, characterized in that: The first liquid supply member further has a first channel connected to the first liquid outlet, and one end of the first channel facing away from the first liquid outlet is connected to the outside of the first liquid supply member.

6. The etching device according to claim 5, characterized in that: The first liquid supply member further has a rolling member movably disposed in the first liquid outlet, and the rolling member divides the first liquid outlet into a first part communicating with the cavity and a second part communicating with the first channel.

7. The etching device according to claim 6, characterized in that: A partial surface of the rolling element is flush with or higher than an end surface of the first liquid supply element facing the second liquid supply element; and / or, The rolling element is a cylinder; And / or, a third part is further formed between the rolling element and the bottom wall of the first liquid outlet, wherein the third part communicates with the first part and the second part.

8. The etching device according to any one of claims 1 to 7, characterized in that: There are multiple liquid supply devices, and the multiple liquid supply devices are arranged along the conveying direction of the conveying device; The etching device further comprises two slide rails, each of the first liquid supply members is slidably arranged on one of the slide rails, and each of the second liquid supply members is slidably arranged on the other of the slide rails; and / or, The arrangement density of the plurality of liquid supply devices along the conveying direction is first large and then small; and / or, In a first direction, the midpoint of the first liquid outlet, the midpoint of the second liquid outlet, and the midpoint of the photovoltaic cell are aligned.

9. An etching method, characterized in that: Using the etching device according to any one of claims 1 to 8 to simultaneously etch two surfaces of a photovoltaic cell, the method comprising: Providing the photovoltaic cell sheet in transmission; Supplying a second etching liquid on the upper surface of the photovoltaic cell through the second liquid outlet of the second liquid supply member, wherein an extension length of the second etching liquid in the first direction is greater than or equal to the preset length; A first etching liquid is supplied to the lower surface of the photovoltaic cell sheet through the first liquid outlet of the first liquid supply member, and an extension length of the first etching liquid in the first direction is less than the preset length.

10. The etching method according to claim 9, characterized in that: The second etching solution and the first etching solution are the same or different etching solutions; Preferably, when the second etching solution and the first etching solution are different etching solutions, the second etching solution is a texturing etching solution, and the first etching solution is a polishing etching solution; Preferably, when supplying the first etching solution to the lower surface of the photovoltaic cell sheet, the method includes: Adjusting the liquid supply rate of the first etching solution; and / or improving the wettability of the first etching solution so as to completely etch the lower surface of the photovoltaic cell.

Images