Monocrystalline silicon cell wet etching device and production process, solar cell piece

Abstract

The application relates to a single-crystal silicon cell piece wet etching device and production process and a solar cell piece. The device comprises an etching groove, a plurality of transmission rollers are rotationally arranged in the etching groove, and the etching groove is further provided with: a transmission cylinder which is sleeved on the outer periphery of the transmission roller; an adjusting roller which is arranged in the transmission cylinder; a same-motion transmission structure which is used for achieving meshing transmission of the transmission roller and the transmission cylinder and achieving meshing transmission of the transmission cylinder and the adjusting roller; a swing arm which is rotationally installed at one end of the end portion of the transmission roller and rotationally connected with the other end of the end portion of the adjusting roller and is used for keeping the transmission cylinder in a simultaneous meshing state with the adjusting roller and the transmission roller; and a tilting mechanism which is used for achieving reciprocating swing of the swing arm at a set angle when the transmission roller continuously rotates, so that the vertical height of the highest part of the arc surface outer periphery wall of the transmission cylinder is intermittently increased or reduced. The application can realize that the silicon piece is in an inclined state during transmission, the flowability of etching liquid on the surface of the silicon piece is stronger, and the etching uniformity of the silicon piece is improved.

Description

Technical Field

[0001] This application relates to the technical field of semiconductor wet etching, and in particular to a wet etching apparatus and manufacturing process for monocrystalline silicon solar cells, and solar cells. Background Technology

[0002] Currently, the fabrication of monocrystalline silicon solar cells mainly includes the following steps: texturing, diffusion, etching, anti-reflective coating deposition, electrode printing, and electrode sintering. There are currently two main etching methods: dry etching and wet etching. Wet etching utilizes a chemical reaction between an etchant and the area to be removed. Its primary purpose is to remove excess PN junctions on the back and edges of the silicon wafer, as well as the PSG layer on the front side.

[0003] Chinese patent application CN202311113227.2 discloses a wet etching apparatus to avoid top Mo shrinkage. The apparatus, arranged sequentially along the substrate transport direction, includes a dry zone, an etching zone, a buffer zone, a washing zone, and an air-drying zone. A first magnet is installed within the etching zone, and a second magnet is installed within the buffer zone. The apparatus also includes a vortex tube, a hot air outlet, and a first exhaust port within the buffer zone. The buffer air knife is arc-shaped, with a hot air pipe positioned diagonally above it. The nozzle of the hot air pipe faces the buffer air knife. Hot air branches of the vortex tube are connected to both the hot air outlet and the hot air pipe. The apparatus also includes a cooling device, with a cold air branch of the vortex tube connected to the cooling device. This invention effectively avoids top Mo shrinkage in Mo / Al and Mo / Al / Mo etching processes, preventing quality issues such as surface contamination and ensuring product quality and yield.

[0004] The aforementioned technologies have the following drawbacks: During the process of a silicon wafer traveling through an etching tank, the etching solution continuously etches the surface of the wafer. However, as the wafer area increases, the etchant displacement in the middle of the wafer and on the side opposite to the direction of travel deteriorates, resulting in an etching solution concentration gradient on the wafer surface during etching, which affects the uniformity of the etching process. Current technologies use tilting etching to mitigate this issue, but excessively large tilt angles may lead to rapid etchant loss, while insufficient tilt angles may not improve etchant displacement. Furthermore, the tilt angle cannot be continuously adjusted. In addition, its application in mass wet etching production of silicon wafers is limited by the precision of tilt angle control and the corrosive effect of the etching solution, making large-scale application difficult. Summary of the Invention

[0005] To address the challenges of precisely controlling the tilt angle and achieving continuous mass production during the large-scale tilting etching of silicon wafers in wet etching processes, this application provides a wet etching apparatus and manufacturing process for monocrystalline silicon solar cells, as well as solar cell wafers.

[0006] The wet etching apparatus for monocrystalline silicon solar cells provided in the first aspect of this application adopts the following technical solution:

[0007] A wet etching apparatus for monocrystalline silicon solar cells includes an etching tank, in which multiple transfer rollers are rotatably arranged. A drive mechanism is provided in the etching tank to drive the multiple transfer rollers to rotate in the same direction and at the same speed. The etching tank also includes:

[0008] A transfer cylinder is sleeved around the outer periphery of the transfer roller and is used to transfer silicon wafers during rotation; the axis of the transfer cylinder is parallel to the axis of the transfer roller.

[0009] An adjusting roller is disposed inside the transmission cylinder, the axis of the adjusting roller is parallel to the axis of the transmission roller, and the line connecting the two axes passes through the axis of the transmission cylinder;

[0010] The synchronous transmission structure is used to realize the meshing transmission between the transmission roller and the transmission cylinder, and to realize the meshing transmission between the transmission cylinder and the adjusting roller;

[0011] A swing arm, one end rotatably mounted to the end of the transmission roller and the other end rotatably connected to the end of the adjusting roller, is used to ensure that the transmission cylinder is always simultaneously engaged with both the adjusting roller and the transmission roller; and

[0012] The tilting mechanism is used to make the swing arm reciprocate at a set angle when the transmission roller rotates continuously, so that the vertical height of the highest point of the outer peripheral wall of the arc surface of the transmission cylinder intermittently increases or decreases.

[0013] The etching solution level in the etching tank is higher than the highest point of the outer peripheral wall of the arc surface of the transmission cylinder.

[0014] Furthermore, the synchronous transmission structure includes:

[0015] The first internal gear ring is coaxially fixed to the inner peripheral wall of the transmission cylinder;

[0016] The first external gear ring is coaxially fixed to the outer peripheral wall of the transfer roller; and

[0017] The second external gear ring is coaxially fixed to the outer peripheral wall of the adjusting roller;

[0018] Both the first external gear ring and the second external gear ring are meshed with the first internal gear ring.

[0019] Furthermore, at least one anti-detachment ring located on the end face of the first internal gear ring is fixedly attached to the inner peripheral wall of the transmission cylinder.

[0020] Furthermore, the tilting mechanism includes:

[0021] An internal toothed arc strip is coaxially mounted on the end face of the transmission roller;

[0022] An external toothed arc strip is fixedly connected to one end of the swing arm near the transmission roller, and the axis of the external toothed arc strip is collinear with the swing axis of the swing arm; and

[0023] A reversing gear is rotatably mounted on the etched groove. The reversing gear meshes with the external toothed arc strip. When the transmission roller rotates to the point where the internal toothed arc strip corresponds to the reversing gear, the reversing gear also meshes with the internal toothed arc strip.

[0024] When the transmission roller rotates to the point where the end of the internal toothed arc strip opposite to its rotation direction is about to disengage from the reversing gear, the swing arm flips so that the axis of the adjusting roller is horizontal and coplanar with the axis of the transmission roller.

[0025] Furthermore, a support frame is installed at the end of the etching groove near the transfer roller, and a rotating shaft is coaxially fixed to the end of the transfer roller. The reversing gear and the rotating shaft are both rotatably mounted on the support frame, and the end of the swing arm near the transfer roller is gapped around the outer circumference of the rotating shaft and rotatably mounted on the support frame.

[0026] Furthermore, a torsional elastic element is provided between the support frame and the swing arm, and is fitted with a gap around the outer periphery of the rotating shaft. One end of the torsional elastic element is connected to the support frame and the other end is connected to the swing arm.

[0027] When the torsional elastic element is in its initial state, the swing arm flips so that the adjusting roller is directly below the transmission roller.

[0028] Furthermore, at least two of the transmission rollers in the etching groove form a transmission group, and when the transmission rollers in the same transmission group rotate, the corresponding adjustment rollers are in the same orientation.

[0029] In two adjacent transmission groups, when the adjusting roller in one transmission group is located directly below the corresponding transmission roller, the axis of the adjusting roller in the other transmission group is horizontally coplanar with the axis of the corresponding transmission roller.

[0030] Furthermore, the internal toothed arc strip is detachably mounted on the end face of the transmission roller, and the support frame is provided with a locking structure for locking the swing arm in a set position.

[0031] The second aspect of this application provides a wet etching process for manufacturing monocrystalline silicon solar cells, which employs the following technical solution:

[0032] A wet etching process for monocrystalline silicon solar cells, based on the aforementioned wet etching apparatus for monocrystalline silicon solar cells, includes the following steps:

[0033] S1. A batch of silicon wafers are sequentially laid out and transported onto multiple transfer cylinders in the etching tank, and the liquid level of the etching solution in the etching tank is controlled to be higher than the upper surface of the silicon wafers on the transfer cylinders;

[0034] S2. The drive mechanism drives multiple transfer rollers to rotate, and when the transfer rollers rotate, they drive the transfer cylinders meshing with them to rotate to transfer the silicon wafers, so that a batch of silicon wafers can pass through the etching solution in the etching tank to complete wet etching.

[0035] S3. During the rotation of the transmission roller, the tilting mechanism drives the swing arm to swing back and forth, so that the vertical height of the highest point of the outer peripheral wall of the arc surface of the transmission cylinder increases or decreases intermittently, thereby making the silicon wafer tilt and flip in a set tilting angle range during the process of passing through the etching liquid.

[0036] S4. After etching is completed, perform water washing, alkali washing, water washing, acid washing, water washing, and drying in sequence.

[0037] The third aspect of this application provides a solar cell using the following technical solution:

[0038] A solar cell is manufactured using the aforementioned wet etching process for monocrystalline silicon solar cells.

[0039] In summary, the beneficial technical effects of this application are as follows:

[0040] 1. By limiting the distance between the adjusting roller and the transmission roller by the swing arm, the axes of the adjusting roller and the transmission roller are always on opposite sides of the axis of the transmission cylinder. This ensures that the transmission cylinder remains engaged with the adjusting roller and the transmission roller simultaneously, regardless of the angle to which the swing arm is rotated. This ensures the stable rotation of the transmission cylinder and the smooth transport of silicon wafers.

[0041] 2. During the continuous rotation of the transfer roller, when the internal toothed arc strip rotates and engages with and disengages from the reversing gear, the swing arm drives the adjusting roller to reciprocate around the axis of the transfer roller at a set angle. This causes the straight-line distance between the highest point of the outer peripheral wall of the transfer cylinder's arc surface and the highest point of the transfer roller's arc surface to gradually increase. This changes the vertical height of the corresponding part of the silicon wafer carried on the transfer cylinder. On the one hand, it allows the silicon wafer to travel at an angle during the transfer process, making the etching solution on the silicon wafer surface more fluid, which helps to reduce the concentration gradient of the etching solution on the silicon wafer surface and improve the etching uniformity. On the other hand, since the vertical height of the highest point of the outer peripheral wall of the transfer cylinder's arc surface increases gradually during the swing arm's swing, it can effectively reduce the disturbance to the etching solution during the dynamic change of the silicon wafer's tilt angle, ensuring the uniformity of the etching solution flow on the tilted silicon wafer surface and avoiding uneven etching problems.

[0042] 3. By grouping at least two transfer rollers into a transfer group and ensuring that multiple adjusting rollers within the same transfer group move in the same manner, the silicon wafer can travel relatively smoothly for a certain period of time after undergoing tilt angle adjustments while being transferred on the transfer cylinder. This effectively avoids the situation where frequent tilt angle adjustments of the silicon wafer lead to excessively fast etching fluid flow, affecting the etching effect. Furthermore, by setting different movement states of the adjusting rollers in two adjacent transfer groups, it can be ensured that the silicon wafer undergoes tilt angle adjustments every time it passes through two adjacent transfer groups, thereby promoting the replacement of etching fluid on the silicon wafer surface. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application;

[0044] Figure 2 This is a schematic diagram of the overall structure of the adjusting roller axis and the transmission roller axis in an embodiment of this application when they are in the same horizontal plane;

[0045] Figure 3 This is a schematic diagram of the overall structure of the adjusting roller in this embodiment of the application when it is located directly below the conveying roller;

[0046] Figure 4 This is a comparison diagram of the swing arm before and after rotating 90° according to an embodiment of this application;

[0047] Figure 5 This embodiment of the application is mainly used to illustrate the cross-sectional structural diagram of the torsional elastic member;

[0048] Figure 6 This is a schematic diagram of the overall structure when two internal toothed arc strips are provided in an embodiment of this application;

[0049] Figure 7 This is a schematic diagram of the overall structure of the internal toothed arc strip in an embodiment of this application when it is detachably installed.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Etching groove;

[0052] 2. Conveyor roller; 21. First outer gear ring; 22. Inner gear arc strip; 23. Rotating shaft; 241. Mounting lug; 242. Mounting bolt;

[0053] 3. Transmission cylinder; 31. First internal gear ring; 32. Anti-detachment ring;

[0054] 4. Adjusting roller; 41. Second outer gear ring;

[0055] 5. Swing arm; 51. External toothed arc strip;

[0056] 6. Support frame; 61. Reversing gear; 62. Torsional elastic element;

[0057] 71. Locking bolt; 72. Arc groove;

[0058] 8. Silicon wafers. Detailed Implementation

[0059] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0060] This application discloses a wet etching apparatus for monocrystalline silicon solar cells. (Refer to...) Figure 1 , Figure 2 and Figure 3 It includes a long strip-shaped etching groove 1, in which multiple parallel transfer rollers 2 are rotatably arranged. The multiple transfer rollers 2 are arranged at equal intervals along the length of the etching groove 1. The etching groove 1 is provided with a drive mechanism for driving the multiple transfer rollers 2 to rotate in the same direction and at the same speed. The drive mechanism is a conventional technical means and will not be described in detail here.

[0061] The etching tank 1 is also equipped with:

[0062] The transfer cylinder 3 is sleeved on the outer periphery of the transfer roller 2 and is used to transfer the silicon wafer 8 during rotation. The axis of the transfer cylinder 3 is parallel to the axis of the transfer roller 2.

[0063] An adjusting roller 4 is located inside the transmission cylinder 3. The axis of the adjusting roller 4 is parallel to the axis of the transmission roller 2, and the line connecting the two axes passes through the axis of the transmission cylinder 3. The adjusting roller 4 and the transmission roller 2 are separated by a gap.

[0064] The synchronous transmission structure is used to realize the meshing transmission between the transmission roller 2 and the transmission cylinder 3, and to realize the meshing transmission between the transmission cylinder 3 and the adjusting roller 4.

[0065] The swing arm 5, with one end rotatably mounted to the end of the transmission roller 2 and the other end rotatably connected to the end of the adjusting roller 4, is used to ensure that the transmission cylinder 3 is always simultaneously engaged with both the adjusting roller 4 and the transmission roller 2, thus ensuring that the transmission roller 2 can stably drive the engaged transmission cylinder 3 to rotate when it rotates.

[0066] The tilting mechanism is used to make the swing arm 5 swing back and forth at a set angle when the transmission roller 2 rotates continuously, so that the vertical height of the highest point of the outer peripheral wall of the arc surface of the transmission cylinder 3 increases or decreases intermittently.

[0067] Furthermore, the level of the etching solution in the etching tank 1 is higher than the highest point of the outer peripheral wall of the arc surface of the transfer cylinder 3.

[0068] In the specific settings, refer to Figure 1 In the etching groove 1, at least two transfer rollers 2 form a transfer group. When the transfer rollers 2 in the same transfer group rotate, the corresponding adjusting rollers 4 are in the same position.

[0069] In two adjacent transmission groups, when the adjusting roller 4 in one transmission group is located directly below the corresponding transmission roller 2, the axis of the adjusting roller 4 in the other transmission group is horizontally coplanar with the axis of the corresponding transmission roller 2.

[0070] Therefore, when the silicon wafer 8 travels through the etching solution in the etching tank 1, the drive mechanism drives multiple transfer rollers 2 to rotate synchronously. When the transfer rollers 2 rotate, the transfer cylinder 3 keeps rotating in the same direction as them by means of the synchronous transmission structure. The swing arm 5 limits the distance between the adjusting roller 4 and the transfer roller 2, so that the axes of the adjusting roller 4 and the transfer roller 2 are always on opposite sides of the axis of the transfer cylinder 3. This ensures that the transfer cylinder 3 always maintains simultaneous engagement with the adjusting roller 4 and the transfer roller 2, regardless of the angle to which the swing arm 5 is rotated. This ensures the stable rotation of the transfer cylinder 3 to smoothly transport the silicon wafer 8.

[0071] As the transfer roller 2 continues to rotate, the tilting mechanism allows the swing arm 5 to drive the adjusting roller 4 to reciprocate around the axis 23 of the transfer roller 2 at a set angle. For example, if the maximum swing angle of the swing arm 5 is 90°, when the swing arm 5 swings to the point where the adjusting roller 4 is directly below the transfer roller 2, assuming the adjusting roller 4 is in its initial position, the highest point of the outer peripheral wall of the arc surface of the transfer cylinder 3 is closest to the highest point of the outer peripheral wall of the arc surface of the transfer roller 2. This means that the corresponding part of the silicon wafer 8 carried on the transfer cylinder 3 is at its lowest point. Figure 4As shown in b; as the transfer roller 2 continues to rotate, the swing arm 5 gradually swings until the axis of the adjusting roller 4 and the axis of the transfer cylinder 3 are on the same horizontal plane, and the swing angle of the swing arm 5 reaches 90°. At this time, the straight-line distance between the highest point of the outer peripheral wall of the arc surface of the transfer cylinder 3 and the highest point of the arc surface of the transfer roller 2 gradually increases, indicating that the corresponding part of the silicon wafer 8 carried on the transfer cylinder 3 gradually rises to the highest point, as shown in b. Figure 4 As shown in 'a'.

[0072] Therefore, on the one hand, the silicon wafer 8 can be moved at an angle during the transmission process, which makes the etchant on the surface of the silicon wafer 8 more fluid, helps to reduce the concentration gradient of the etchant on the surface of the silicon wafer 8, and improves the etching uniformity of the silicon wafer 8. On the other hand, since the vertical height of the highest point of the outer peripheral wall of the arc surface of the transmission cylinder 3 increases gradually during the swing of the swing arm 5, the disturbance of the etchant to the silicon wafer 8 during the dynamic change of the tilt angle can be effectively reduced, which can ensure the uniformity of the flow of the etchant on the tilted surface of the silicon wafer 8, so as to avoid the problem of uneven etching.

[0073] By grouping at least two transfer rollers 2 into a transfer group and ensuring that multiple adjusting rollers 4 within the same transfer group move in the same manner, the silicon wafer 8 can travel relatively smoothly for a certain period after tilt angle adjustments during its transfer on the transfer cylinder 3. This effectively prevents the silicon wafer 8 from undergoing frequent tilt angle adjustments, which could lead to excessively fast etching fluid flow and affect the etching effect. Furthermore, by setting different movement states for the adjusting rollers 4 in adjacent transfer groups, it can be ensured that the silicon wafer 8 undergoes tilt angle adjustments every time it passes through two adjacent transfer groups, thereby promoting the replacement of etching fluid on the surface of the silicon wafer 8.

[0074] Specifically, refer to Figure 2 The synchronous transmission structure includes:

[0075] The first internal gear ring 31 is coaxially fixed to the inner peripheral wall of the transmission cylinder 3;

[0076] The first external gear ring 21 is coaxially fixed to the outer peripheral wall of the transfer roller 2; and

[0077] The second outer gear ring 41 is coaxially fixed to the outer peripheral wall of the adjusting roller 4;

[0078] Both the first external gear ring 21 and the second external gear ring 41 are meshed with the first internal gear ring 31, and at least one anti-detachment ring 32 located on the end face of the first internal gear ring 31 is fixedly connected to the inner peripheral wall of the transmission cylinder 3. In a specific configuration, the first internal gear ring 31 is provided at both ends of the transmission cylinder 3, the first external gear ring 21 is provided at both ends of the transmission roller 2, and the second external gear ring 41 is provided at both ends of the adjusting roller 4. Therefore, the anti-detachment ring 32 can be provided only at one end of the transmission cylinder 3, or one or two can be provided at both ends of the transmission cylinder 3.

[0079] Therefore, when the transmission roller 2 rotates under the drive mechanism, it drives the transmission cylinder 3 to rotate synchronously through the meshing connection of the first outer gear ring 21 and the first inner gear ring 31, so as to realize the effective transmission of silicon wafer 8 by the transmission cylinder 3; while the meshing of the second outer gear ring 41 and the first inner gear ring 31 ensures that when the swing arm 5 drives the adjusting roller 4 to move forward or backward relative to the transmission cylinder 3, it will not interfere with the normal rotation of the transmission cylinder 3, and at the same time, it must ensure the smoothness of the rotation of the transmission cylinder 3; the anti-disengagement ring 32 is set to ensure that the first inner gear ring 31, the first outer gear ring 21 and the second outer gear ring 41 are always in a meshing state, and to prevent them from disengaging during the meshing transmission process.

[0080] Furthermore, refer to Figure 2 and Figure 3 The aforementioned tilting mechanism includes:

[0081] The internal toothed arc strip 22 is coaxially mounted on the end face of the transmission roller 2, and the maximum swing angle corresponding to the aforementioned swing arm 5 is 90°. In this embodiment, the internal toothed arc strip 22 is a quarter circle arc.

[0082] An external toothed arc strip 51 is fixedly connected to one end of the swing arm 5 near the transmission roller 2, and the axis of the external toothed arc strip 51 is collinear with the swing axis of the swing arm 5; and

[0083] The reversing gear 61 is rotatably mounted on the etching groove 1. The reversing gear 61 is meshed with the external toothed arc strip 51. When the transmission roller 2 rotates to the point where the internal toothed arc strip 22 corresponds to the reversing gear 61, the reversing gear 61 is also meshed with the internal toothed arc strip 22.

[0084] When the transmission roller 2 rotates to the point where the end of the internal toothed arc strip 22 opposite to its rotation direction is about to disengage from the reversing gear 61, the swing arm 5 flips so that the axis of the adjusting roller 4 is horizontal and coplanar with the axis of the transmission roller 2.

[0085] Specifically, a support frame 6 is installed at the end of the etching groove 1 near the transfer roller 2, and a rotating shaft 23 is coaxially fixed at the end of the transfer roller 2. The drive mechanism is used to drive the rotating shaft 23 to rotate. The reversing gear 61 and the rotating shaft 23 are both rotatably mounted on the support frame 6. The end of the swing arm 5 near the transfer roller 2 is gapped around the outer circumference of the rotating shaft 23 and rotatably mounted on the support frame 6.

[0086] Furthermore, referring to Figure 5 A torsional elastic element 62 is provided between the support frame 6 and the swing arm 5 and is sleeved on the outer periphery of the rotating shaft 23. One end of the torsional elastic element 62 is connected to the support frame 6 and the other end is connected to the swing arm 5. The torsional elastic element 62 is set as a torsion spring and is made of high molecular plastics such as PTFE, PEEK, PVDF, and PPS that are resistant to acid and alkali corrosion and have good mechanical properties.

[0087] When the torsion elastic element 62 is in its initial state, the swing arm 5 flips up so that the adjusting roller 4 is directly below the transmission roller 2.

[0088] Therefore, when the adjusting roller 4 on the swing arm 5 is in the aforementioned initial position, the corresponding part of the silicon wafer 8 carried on the transmission cylinder 3 is at its lowest point. At this time, the reversing gear 61 is not in contact with the internal toothed arc strip 22 on the transmission roller 2. Figure 4 As shown in b, with the rotation of the transmission roller 2, for example clockwise, it drives the internal toothed arc strip 22 to rotate clockwise, and also drives the transmission cylinder 3 meshing with it to rotate clockwise. When the internal toothed arc strip 22 rotates to mesh with the reversing gear 61, as the transmission roller 2 continues to rotate, the internal toothed arc strip 22 drives the reversing gear 61 to rotate clockwise as well. The reversing gear 61 then drives the external toothed arc strip 51 meshing with it to swing the swing arm 5 counterclockwise on the support frame 6, until the internal toothed arc strip 22 is about to disengage from the reversing gear 61, as shown in b. Figure 4 As shown in a, the swing arm 5 flips so that the axis of the adjusting roller 4 is horizontal and coplanar with the axis of the transmission roller 2, so that the corresponding part of the silicon wafer 8 carried on the transmission cylinder 3 is at the highest point, which can realize the smooth tilt angle adjustment of the silicon wafer 8.

[0089] As the swing arm 5 flips over, the torsional elastic element 62 is torsionally deformed. Therefore, when the transmission roller 2 continues to rotate, the internal tooth arc strip 22 and the reversing gear 61 completely disengage. The swing arm 5 will swing clockwise in the opposite direction under the torsional deformation force of the torsional elastic element 62. Then, by adjusting the engagement between the roller 4 and the transmission cylinder 3, the vertical height of the highest point of the outer peripheral wall of the arc surface of the transmission cylinder 3 is reduced while maintaining a stable clockwise rotation. This allows for the adjustment of the tilt angle of the silicon wafer 8 carried on it.

[0090] However, considering that although the swing arm 5 will be subject to the resistance of the etching fluid when it swings clockwise under the deformation force of the torsional elastic element 62, which reduces the rotation speed of the swing arm 5, there is still a possibility that the vertical height of the corresponding part of the silicon wafer 8 carried on the transmission cylinder 3 will drop too quickly, which may cause turbulence of the etching fluid on the surface of the silicon wafer 8 or the silicon wafer 8 to shift in position on the transmission cylinder 3. Therefore, in another feasible embodiment, an acid and alkali resistant damping rubber ring (not shown in the figure) can be set between the swing arm 5 and the support frame 6 to reduce the rotation speed of the swing arm 5, so that the vertical height of the corresponding part of the silicon wafer 8 carried on the transmission cylinder 3 drops more gently.

[0091] Furthermore, considering that the internal toothed arc strip 22 is set as a quarter-circle arc, during the rotation of the transmission roller 2, the vertical height of the corresponding part of the silicon wafer 8 carried on the transmission cylinder 3 is in the rising position for one-third of the time when the corresponding part of the silicon wafer 8 carried on the transmission cylinder 3 is at its lowest position. It is possible that when the silicon wafer 8 crosses two adjacent transmission groups, the highest point of the outer arc surface of the transmission cylinder 3 in both transmission groups is at its lowest position, so that the silicon wafer 8 cannot adjust its tilt angle when passing through the two transmission groups.

[0092] Therefore, in another feasible embodiment, referring to Figure 6 Two quarter-circle inner toothed arc strips 22 are set and distributed in an equally spaced circular array around the axis of the transmission roller 2. This ensures that the transmission cylinders 3 in two adjacent transmission groups are always in different states, so as to ensure the smooth adjustment of the tilt angle of the silicon wafer 8.

[0093] Meanwhile, considering that different etching solutions have different requirements for tilt etching, the etching apparatus of this application is designed to be suitable for different etching needs.

[0094] In other feasible embodiments, refer to Figure 7 The internal toothed arc strip 22 can be detachably installed on the end face of the transmission roller 2. The support frame 6 is provided with a locking structure for locking the swing arm 5 in a set position. Specifically, both ends of the internal toothed arc strip 22 are fixedly connected with mounting ears 241, and mounting bolts 242 that are threaded to the end face of the transmission roller 2 are threaded through the mounting ears 241. The locking structure includes several locking bolts 71 that are threaded to the swing arm 5. The support frame 6 is provided with an arc groove 72 whose axis is collinear with the swing axis of the swing arm 5, and the locking bolts 71 are threaded through the arc groove 72.

[0095] In this way, when it is not necessary to tilt and etch the silicon wafer 8 during the transfer of the silicon wafer 8, the mounting bolt 242 can be unscrewed and the internal toothed arc strip 22 can be removed. At the same time, the swing arm 5 can be swung to a suitable position, and the locking bolt 71 can be passed through the arc groove 72 and screwed onto the swing arm 5. Tightening the locking bolt 71 can fix the swing arm 5. This allows for flexible switching between different wet etching processes, greatly expanding the application scope of this application.

[0096] In addition, all components of the wet etching apparatus of this application are made of acid and alkali resistant polymer plastics, such as PEEK, PVDF, PPS, PC, etc.

[0097] This application discloses a wet etching process for monocrystalline silicon solar cells, based on the aforementioned wet etching apparatus for monocrystalline silicon solar cells, with reference to... Figure 1 It includes the following steps:

[0098] S1. A batch of silicon wafers 8 are sequentially laid out and transported to multiple transfer cylinders 3 in the etching tank 1, and the liquid level of the etching solution in the etching tank 1 is controlled to be higher than the upper surface of the silicon wafers 8 on the transfer cylinders 3.

[0099] S2. Multiple transfer rollers 2 are driven to rotate by a drive mechanism. When the transfer rollers 2 rotate, they drive the transfer cylinders 3 that mesh with them to rotate to transfer the silicon wafers 8, so that a batch of silicon wafers 8 can travel through the etching solution in the etching tank 1 to complete wet etching.

[0100] S3. During the rotation of the transfer roller 2, the swing arm 5 is driven to swing back and forth by means of the tilting mechanism, so that the vertical height of the highest point of the outer peripheral wall of the arc surface of the transfer cylinder 3 increases or decreases intermittently, thereby making the silicon wafer 8 tilt and flip in a state within a set tilt angle range during the process of passing through the etching liquid.

[0101] S4. After etching is completed, perform water washing, alkali washing, water washing, acid washing, water washing, and drying in sequence.

[0102] This application discloses a solar cell, which is manufactured by the above-described wet etching process for monocrystalline silicon solar cells.

[0103] The implementation principle of the wet etching apparatus for monocrystalline silicon solar cells in this application is as follows:

[0104] The distance between the adjusting roller 4 and the transmission roller 2 is limited by the swing arm 5, ensuring that the axes of the adjusting roller 4 and the transmission roller 2 are always aligned on opposite sides of the axis of the transmission cylinder 3. This ensures that the transmission cylinder 3 remains simultaneously engaged with both the adjusting roller 4 and the transmission roller 2, regardless of the angle to which the swing arm 5 is rotated. This guarantees the stable rotation of the transmission cylinder 3 for smooth transport of the silicon wafer 8. Therefore, as the transmission roller 2 rotates continuously, when the internal toothed arc strip 22 engages with and disengages from the reversing gear 61, the swing arm 5 drives the adjusting roller 4 to reciprocate around the axis 23 of the transmission roller 2 at a set angle. This causes the straight-line distance between the highest point of the outer peripheral wall of the arc surface of the transmission cylinder 3 and the highest point of the arc surface of the transmission roller 2 to gradually increase, thus changing the vertical height of the corresponding part of the silicon wafer 8 carried on the transmission cylinder 3.

[0105] Therefore, on the one hand, the silicon wafer 8 can be moved at an angle during the transmission process, which makes the etchant on the surface of the silicon wafer 8 more fluid, helps to reduce the concentration gradient of the etchant on the surface of the silicon wafer 8, and improves the etching uniformity of the silicon wafer 8. On the other hand, since the vertical height of the highest point of the outer peripheral wall of the arc surface of the transmission cylinder 3 increases gradually during the swing of the swing arm 5, the disturbance of the etchant to the silicon wafer 8 during the dynamic change of the tilt angle can be effectively reduced, which can ensure the uniformity of the flow of the etchant on the tilted surface of the silicon wafer 8, so as to avoid the problem of uneven etching.

[0106] By grouping at least two transfer rollers 2 into a transfer group and ensuring that multiple adjusting rollers 4 within the same transfer group move in the same manner, the silicon wafer 8 can travel relatively smoothly for a certain period after tilt angle adjustments during its transfer on the transfer cylinder 3. This effectively prevents the silicon wafer 8 from undergoing frequent tilt angle adjustments, which could lead to excessively fast etching fluid flow and affect the etching effect. Furthermore, by setting different movement states for the adjusting rollers 4 in adjacent transfer groups, it can be ensured that the silicon wafer 8 undergoes tilt angle adjustments every time it passes through two adjacent transfer groups, thereby promoting the replacement of etching fluid on the surface of the silicon wafer 8.

[0107] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," "third," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" and similar terms mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0108] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A wet etching apparatus for monocrystalline silicon solar cells, comprising an etching tank (1), wherein a plurality of transfer rollers (2) are rotatably disposed in the etching tank (1), and a driving mechanism is provided in the etching tank (1) for driving the plurality of transfer rollers (2) to rotate in the same direction and at the same speed, characterized in that, The etching groove (1) is also provided with: A transfer cylinder (3) is sleeved on the outer periphery of the transfer roller (2) and is used to transfer silicon wafers (8) during rotation. The axis of the transfer cylinder (3) is parallel to the axis of the transfer roller (2). An adjusting roller (4) is provided inside the transmission cylinder (3). The axis of the adjusting roller (4) is parallel to the axis of the transmission roller (2), and the line connecting the two axes passes through the axis of the transmission cylinder (3). The synchronous transmission structure is used to realize the meshing transmission between the transmission roller (2) and the transmission cylinder (3), and to realize the meshing transmission between the transmission cylinder (3) and the adjusting roller (4); A swing arm (5), one end of which is rotatably mounted to the end of the transmission roller (2) and the other end of which is rotatably connected to the end of the adjusting roller (4), is used to ensure that the transmission cylinder (3) is always simultaneously engaged with the adjusting roller (4) and the transmission roller (2); and The tilting mechanism is used to make the swing arm (5) swing back and forth at a set angle when the transmission roller (2) rotates continuously, so that the vertical height of the highest point of the outer peripheral wall of the arc surface of the transmission cylinder (3) increases or decreases intermittently. The etching liquid level in the etching tank (1) is higher than the highest point of the outer peripheral wall of the arc surface of the transmission cylinder (3); At least two of the transmission rollers (2) in the etching groove (1) form a transmission group. When the transmission rollers (2) in the same transmission group rotate, the corresponding adjustment rollers (4) are in the same position. In two adjacent transmission groups, when the adjusting roller (4) in one of the transmission groups is located directly below the corresponding transmission roller (2), the axis of the adjusting roller (4) in the other transmission group is horizontally coplanar with the axis of the corresponding transmission roller (2).

2. The wet etching apparatus for monocrystalline silicon solar cells according to claim 1, characterized in that, The synchronous transmission structure includes: The first internal gear ring (31) is coaxially fixed to the inner peripheral wall of the transmission cylinder (3); The first external gear ring (21) is coaxially fixed to the outer peripheral wall of the transmission roller (2); and The second external gear ring (41) is coaxially fixed to the outer peripheral wall of the adjusting roller (4); Both the first external gear ring (21) and the second external gear ring (41) are meshed with the first internal gear ring (31).

3. The wet etching apparatus for monocrystalline silicon solar cells according to claim 2, characterized in that, At least one anti-detachment ring (32) located on the end face of the first internal gear ring (31) is fixedly attached to the inner peripheral wall of the transmission cylinder (3).

4. The wet etching apparatus for monocrystalline silicon solar cells according to claim 1, characterized in that, The tilt adjustment mechanism includes: The internal toothed arc strip (22) is coaxially mounted on the end face of the transmission roller (2); An external toothed arc strip (51) is fixed to one end of the swing arm (5) near the transmission roller (2), and the axis of the external toothed arc strip (51) is collinear with the swing axis of the swing arm (5); and A reversing gear (61) is rotatably mounted on the etching groove (1). The reversing gear (61) meshes with the external toothed arc strip (51). When the transmission roller (2) rotates to the point where the internal toothed arc strip (22) corresponds to the reversing gear (61), the reversing gear (61) also meshes with the internal toothed arc strip (22). When the transmission roller (2) rotates to the point where the end of the internal toothed arc strip (22) opposite to its rotation direction is about to disengage from the reversing gear (61), the swing arm (5) flips so that the axis of the adjusting roller (4) is horizontal and coplanar with the axis of the transmission roller (2).

5. The wet etching apparatus for monocrystalline silicon solar cells according to claim 4, characterized in that, A support frame (6) is installed at the end of the etching groove (1) near the end of the transmission roller (2). A rotating shaft (23) is coaxially fixed at the end of the transmission roller (2). The reversing gear (61) and the rotating shaft (23) are both rotatably mounted on the support frame (6). The end of the swing arm (5) near the transmission roller (2) is gapped around the outer circumference of the rotating shaft (23) and rotatably mounted on the support frame (6).

6. The wet etching apparatus for monocrystalline silicon solar cells according to claim 5, characterized in that, A torsional elastic element (62) is provided between the support frame (6) and the swing arm (5) and is sleeved on the outer periphery of the rotating shaft (23). One end of the torsional elastic element (62) is connected to the support frame (6) and the other end is connected to the swing arm (5). When the torsional elastic element (62) is in its initial state, the swing arm (5) flips up so that the adjusting roller (4) is directly below the transmission roller (2).

7. The wet etching apparatus for monocrystalline silicon solar cells according to claim 5, characterized in that, The internal toothed arc strip (22) can be detachably installed on the end face of the transmission roller (2), and the support frame (6) is provided with a locking structure for locking the swing arm (5) in a set position.

8. A wet etching process for monocrystalline silicon solar cells, based on the wet etching apparatus for monocrystalline silicon solar cells as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. A batch of silicon wafers (8) are sequentially laid out and transported to multiple transfer cylinders (3) in the etching tank (1), and the liquid level of the etching liquid in the etching tank (1) is controlled to be higher than the upper surface of the silicon wafers (8) on the transfer cylinders (3); S2. The drive mechanism drives multiple transfer rollers (2) to rotate. When the transfer rollers (2) rotate, they drive the transfer cylinders (3) that mesh with them to rotate to transfer the silicon wafers (8), so that a batch of silicon wafers (8) can pass through the etching solution in the etching tank (1) to complete wet etching. S3. During the rotation of the transmission roller (2), the swing arm (5) is driven to swing back and forth by means of the tilting mechanism, so that the vertical height of the highest point of the outer peripheral wall of the arc surface of the transmission cylinder (3) increases or decreases intermittently, thereby making the silicon wafer (8) tilt and flip in a set tilting angle range during the process of passing through the etching liquid. S4. After etching is completed, perform water washing, alkali washing, water washing, acid washing, water washing, and drying in sequence.

9. A solar cell, manufactured using the wet etching process for monocrystalline silicon solar cells as described in claim 8.

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