Method for manufacturing a solar cell and solar cell
Patent Information
- Application Number
- CN202510558940.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-29
- Publication Date
- 2026-10-30
AI Technical Summary
[0002]在目前铜互联制程中，工艺流程包括来料黄膜电池片-涂布正面-烘干-涂布背面-烘干-打印正面-翻转-打印背面-显影-包边-烘干-电镀-去膜回刻-光注入-化锡-测试分选等工序，其中显影工序、电镀工序、去膜回刻工序以及化锡工序还会使用到相应的化学品，从而使得该工艺流程不仅耗时较长，而且工艺成本高
[0037]对比现有技术，本申请实施例的有益效果为：该太阳电池的制备方法及太阳电池，制备方法包括：提供一太阳电池基底，太阳电池基底的表面具有金属种子层；对太阳电池基底进行预冷处理；在预冷处理后的太阳电池基底的金属种子层非栅线区域涂布液态石蜡，以形成具有图形化凹槽的第一石蜡层；在图形化凹槽内电镀形成金属栅线。通过本申请的实施方式，涂布前先对太阳电池基底进行预冷处理，可以有效地加快涂布于金属种子层的液态石蜡的固化速度，不仅可以缩短工艺时长，而且可以更好地保证图形化凹槽两侧的第一石蜡层的形貌均匀性且呈矩形形貌，进而使得太阳电池的金属栅线粗细均匀且呈矩形形貌，提高了太阳电池的良率及效率。在本实施例中涂布即可形成图形化凹槽，涂布时，金属种子层的栅线区域直接露出于图形化凹槽，无需在涂布后进行显影或者其他处理形成图形化凹槽，因此，图形化凹槽底部不会有残留的第一石蜡层，从而保证了金属栅线与金属种子层的结合力。而且本实施例省去了打印工序和显影工序，也就是说，无需设置打印设备以及显影设备，并且还可以省去显影工序所需使用的化学品，进而有效地简化了工艺流程，降低了工艺成本。
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Figure CN123021806A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solar cell manufacturing technology, and in particular to a method for preparing a solar cell and a solar cell. Background Technology
[0002] In current copper interconnect manufacturing processes, the workflow includes incoming yellow film solar cells – front-side coating – drying – back-side coating – drying – front-side printing – flipping – back-side printing – development – edge wrapping – drying – electroplating – film removal and re-etching – photoinjection – tinning – testing and sorting. The development, electroplating, film removal and re-etching, and tinning processes utilize corresponding chemicals, making the process not only time-consuming but also costly. Furthermore, insufficient development can result in residual photosensitive adhesive at the bottom of the subsequently formed metal grid lines, as well as uneven grid line thickness and poor morphology, thus affecting the yield and efficiency of the solar cells. Summary of the Invention
[0003] This application provides a method for preparing a solar cell and a solar cell that can effectively simplify the process flow, reduce process costs, and improve the product yield and efficiency of the solar cell by producing uniform metal grid lines with a rectangular shape.
[0004] In a first aspect, the method for preparing a solar cell provided in the embodiments of this application includes:
[0005] A solar cell substrate is provided, the surface of which has a metal seed layer;
[0006] The solar cell substrate is pre-cooled.
[0007] Liquid paraffin is applied to the non-grid area of the metal seed layer of the solar cell substrate after pre-cooling treatment to form a first paraffin layer with patterned grooves.
[0008] Metal grid lines are formed by electroplating within the patterned grooves.
[0009] In some embodiments, the precooling treatment satisfies at least one of the following (i) to (ii):
[0010] (i) The temperature of the precooling treatment is 0℃~10℃;
[0011] (ii) The duration of the precooling process is 0.5S to 3S.
[0012] In some embodiments, the liquid paraffin comprises 1% to 10% by mass of expanded graphite.
[0013] In some embodiments, a coating apparatus is used to coat the non-grid area of the metal seed layer with liquid paraffin, the coating apparatus including a printing platform, a printing screen and a screen squeegee;
[0014] The method of applying liquid paraffin to the non-gateline areas of the metal seed layer using a coating device includes:
[0015] The printing screen is applied to the upper surface of the solar cell substrate placed on the printing platform;
[0016] The liquid paraffin is coated onto a printing screen covering the upper surface of the solar cell substrate;
[0017] The squeegee is moved against the upper surface of the printing screen coated with the liquid paraffin, so that the liquid paraffin is applied through the printing screen to the non-grid area of the metal seed layer.
[0018] In some embodiments, after forming the first paraffin layer with patterned grooves, the first paraffin layer is further subjected to a first drying process to solidify the first paraffin layer.
[0019] The first drying process satisfies at least one of the following (iii) to (iv):
[0020] (iii) The temperature of the first drying treatment is 20℃~30℃;
[0021] (iv) The duration of the first drying process is 3 min to 5 min.
[0022] In some embodiments, after forming the first paraffin layer with patterned grooves, the method further includes:
[0023] Liquid paraffin is applied to the edge of the solar cell substrate for edge banding to form a second paraffin layer at the edge of the solar cell substrate.
[0024] In some embodiments, after forming the second paraffin layer at the edge of the solar cell substrate, the process further includes performing a second drying treatment on the second paraffin layer;
[0025] The second drying process satisfies at least one of the following (v) to (vi):
[0026] (v) The temperature of the second drying treatment is 20°C to 30°C;
[0027] (vi) The duration of the second drying process is 1 min to 2 min.
[0028] In some embodiments, after electroplating the metal grid lines within the patterned grooves, the method further includes:
[0029] The first paraffin layer is heated to melt it.
[0030] The first layer of paraffin wax is rinsed off to remove it.
[0031] In some embodiments, the heat treatment satisfies at least one of (vii) to (viii) below, and / or the rinsing treatment satisfies at least one of (ix) to (x) below:
[0032] (vii) The temperature of the heat treatment is 60℃~80℃;
[0033] (viii) The duration of the heat treatment is 1 min to 2 min;
[0034] (ix) The rinsing temperature is 60℃~70℃;
[0035] (x) The duration of the rinsing process is 20S to 40S.
[0036] Secondly, the solar cells provided in the embodiments of this application are obtained by using the solar cell preparation method provided in any of the above embodiments.
[0037] Compared with the prior art, the beneficial effects of the embodiments of this application are as follows: The method for preparing the solar cell and the solar cell include: providing a solar cell substrate, the surface of which has a metal seed layer; pre-cooling the solar cell substrate; coating the non-grid area of the metal seed layer of the pre-cooled solar cell substrate with liquid paraffin to form a first paraffin layer with patterned grooves; and electroplating metal grid lines within the patterned grooves. Through the embodiments of this application, pre-cooling the solar cell substrate before coating can effectively accelerate the curing speed of the liquid paraffin coated on the metal seed layer, which not only shortens the process time but also better ensures the uniformity and rectangular shape of the first paraffin layer on both sides of the patterned grooves. This results in uniform thickness and a rectangular shape for the metal grid lines of the solar cell, improving the yield and efficiency of the solar cell. In this embodiment, patterned grooves can be formed simply by coating. During coating, the grid lines of the metal seed layer are directly exposed in the patterned grooves, eliminating the need for post-coating development or other treatments to form the grooves. Therefore, no residual first paraffin layer remains at the bottom of the patterned grooves, ensuring the adhesion between the metal grid lines and the metal seed layer. Furthermore, this embodiment eliminates the printing and developing processes, meaning there is no need for printing or developing equipment, and the chemicals required for the developing process are also eliminated, effectively simplifying the process and reducing costs. Attached Figure Description
[0038] Figure 1 This is a schematic flowchart illustrating a method for fabricating a solar cell according to an embodiment of this application.
[0039] Figure 2 This is a schematic diagram of the solar cell substrate structure provided in step S11 of one embodiment of this application.
[0040] Figure 3 This is a schematic diagram of the structure of the intermediate obtained in step S13 of one embodiment of this application.
[0041] Figure 4 This is a schematic diagram of the structure of the intermediate obtained in step S14 of one embodiment of this application.
[0042] Figure 5 This is a schematic diagram of the structure of the intermediate obtained in step S17 of one embodiment of this application.
[0043] Figure 6 This is a schematic diagram of the coating apparatus structure in one embodiment of this application.
[0044] Figure 7 This is a schematic diagram of the printing screen structure in one embodiment of this application. Detailed Implementation
[0045] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.
[0046] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.
[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
[0048] As used in this article, the description of "a1~a2" means "greater than or equal to a1" and "less than or equal to a2". For example, if x is 0~1, it means: 0≤x≤1.
[0049] like Figure 1 As shown, this is a method for preparing a solar cell according to one embodiment of this application.
[0050] like Figure 1 As shown, the method for fabricating this solar cell includes the following steps S11 to S14:
[0051] Step S11: A solar cell substrate 100 is provided, the surface of which has a metal seed layer 110.
[0052] In some embodiments, the solar cell substrate 100 can be a heterojunction (HJT) cell substrate. Please refer to [reference needed]. Figure 2 As shown, the solar cell substrate 100 includes a silicon wafer substrate 120, a first intrinsic amorphous silicon layer 130 stacked on the upper surface of the silicon wafer substrate 120, a second intrinsic amorphous silicon layer 140 stacked on the lower surface of the silicon wafer substrate 120, an N-type doped amorphous silicon layer 150 stacked on the side of the first intrinsic amorphous silicon layer 130 away from the silicon wafer substrate 120, a P-type doped amorphous silicon layer 160 stacked on the side of the second intrinsic amorphous silicon layer 140 away from the silicon wafer substrate 120, a first conductive layer 170 stacked on the side of the N-type doped amorphous silicon layer 150 away from the silicon wafer substrate 120, a second conductive layer 180 stacked on the side of the P-type doped amorphous silicon layer 160 away from the silicon wafer substrate 120, and metal seed layers 110 respectively stacked on the side of the first conductive layer 170 away from the silicon wafer substrate 120 and the side of the second conductive layer 180 away from the silicon wafer substrate 120.
[0053] In one implementation, step S11 may specifically include steps S111 to S114:
[0054] Step S111: The silicon wafer substrate 120 is texturized and cleaned to form a uniform "positive pyramid" textured surface on the silicon wafer surface.
[0055] Among them, the silicon substrate 120 can be an N-type single crystal silicon wafer, and the bottom surface size (side length of the square bottom surface) of the textured pyramid structure can be 2μm to 8μm.
[0056] In step S112, a first intrinsic amorphous silicon layer 130 and an N-type doped amorphous silicon layer 150 are sequentially deposited on the upper surface of the texturized silicon wafer substrate 120 using a PECVD (plasma enhanced chemical vapor deposition) plasma deposition equipment, and a second intrinsic amorphous silicon layer 140 and a P-type doped amorphous silicon layer 160 are sequentially deposited on the lower surface of the texturized silicon wafer substrate 120 using a PECVD plasma deposition equipment.
[0057] The thickness of the first intrinsic amorphous silicon layer 130 can be 3nm to 6nm, the thickness of the second intrinsic amorphous silicon layer 140 can be 3nm to 9nm, the thickness of the N-type doped amorphous silicon layer 150 can be 5nm to 10nm, and the thickness of the P-type doped amorphous silicon layer 160 can be 5nm to 15nm.
[0058] Step S113: A first conductive layer 170 and a second conductive layer 180 are deposited on an N-type doped amorphous silicon layer 150 and a P-type doped amorphous silicon layer 160, respectively, using a PVD (Physical Vapor Deposition) magnetron sputtering device.
[0059] The first conductive layer 170 and the second conductive layer 180 can each be a TCO (Transparent Conductive Oxides) thin film. For example, the first conductive layer 170 and the second conductive layer 180 can each be an ITO (Indium Tin Oxide) transparent conductive thin film. The thickness of the first conductive layer 170 and the second conductive layer 180 can each be 90 nm to 110 nm.
[0060] Step S114: A metal seed layer 110 is deposited on the first conductive layer 170 and the second conductive layer 180 using a PVD magnetron sputtering apparatus. The metal seed layer 110 may be a copper seed layer. For example, the thickness of the metal seed layer 110 may be 100 nm to 250 nm.
[0061] Step S12: Pre-cool the solar cell substrate 100.
[0062] In this embodiment, pre-cooling the solar cell substrate 100 can shorten the curing time of the liquid paraffin. This not only shortens the process time but also ensures that the liquid paraffin on both sides of the patterned groove 210 retains its shape and does not collapse after curing. This results in the first paraffin layer 200 on both sides of the patterned groove 210 having a uniform and rectangular shape, laying a good foundation for the subsequent formation of the metal grid lines 300 and improving the yield and efficiency of the solar cell.
[0063] In some embodiments, the pre-cooling temperature is 0°C to 10°C. Exemplarily, the pre-cooling temperature can be, but is not limited to, 0°C, 2°C, 3°C, 5°C, 6°C, 8°C, 9°C, or 10°C.
[0064] In some implementations, the precooling process lasts from 0.5 to 3 seconds. For example, the precooling process can last for, but is not limited to, 0.5 seconds, 1 second, 1.6 seconds, 2 seconds, 2.5 seconds, or 3 seconds.
[0065] Step S13: Liquid paraffin is applied to the non-grid area of the metal seed layer 110 of the pre-cooled solar cell substrate 100 to form a first paraffin layer 200 with patterned grooves 210. Please refer to [reference needed]. Figure 3 As shown.
[0066] In related technologies, a photosensitive emulsion is first coated onto a metal seed layer to form a photosensitive emulsion layer that completely covers the metal seed layer. Then, the designed grid pattern is laser-printed onto the photosensitive emulsion layer and exposed. During this process, the photosensitive emulsion layer undergoes photodegradation (non-grid area is exposed), distinguishing it from the unexposed areas (i.e., the grid area). The unexposed photosensitive emulsion layer (grid area) is then removed using a sodium carbonate (Na2CO3) solution to form patterned grooves, exposing the grid area of the metal seed layer. Therefore, in these technologies, forming patterned grooves on the solar cell substrate requires printing and developing equipment, and the developing process also requires chemicals (sodium carbonate solution), making the process complex and costly. Furthermore, insufficient developing can result in residual photosensitive emulsion at the bottom of the patterned grooves, affecting the adhesion between the metal grid lines and the metal seed layer.
[0067] In this embodiment, liquid paraffin is applied only to the non-grid area of the metal seed layer, while the grid area of the metal seed layer is not coated with liquid paraffin. This allows the first paraffin layer 200 to have patterned grooves 210 corresponding to the grid area, eliminating the need for printing and developing. This eliminates the need for printing equipment, developing equipment, and chemicals required for developing, effectively simplifying the process and reducing costs. Furthermore, since the patterned grooves 210 are formed simply by coating in this embodiment, the grid area of the metal seed layer 110 is directly exposed within the patterned grooves 210. No further developing or other processing is required after coating to form the patterned grooves 210. Therefore, no residual first paraffin layer 200 remains at the bottom of the patterned grooves 210, ensuring the adhesion between the metal grid 300 and the metal seed layer 110 and improving the yield and efficiency of the solar cell.
[0068] In some embodiments, the thickness of the first paraffin layer 200 is 8 μm to 14 μm. As an example, the thickness of the first paraffin layer 200 can be, but is not limited to, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm or 14 μm.
[0069] In some embodiments, the liquid paraffin comprises 1% to 10% by weight of expanded graphite. As an example, the liquid paraffin may include, but is not limited to, 1%, 2%, 4%, 5%, 6%, 7%, 9%, or 10% by weight of expanded graphite.
[0070] Under the same working conditions, compared with pure paraffin wax, the melting time of composite paraffin wax with added 1%, 2%, and 5% expanded graphite is reduced by 2.14 times, 2.81 times, and 9.74 times, respectively. Compared with pure paraffin wax, the solidification time of composite paraffin wax with added 1%, 2%, and 5% expanded graphite is reduced by 0.77 times, 1.05 times, and 3.76 times, respectively. Therefore, in this embodiment, adding expanded graphite to pure paraffin wax liquid can not only accelerate the melting rate of the first paraffin layer 200, but also accelerate the solidification rate of the first paraffin layer 200, thereby further shortening the process time. Furthermore, it can better ensure the morphological uniformity of the first paraffin layer 200 on both sides of the patterned groove 210, thereby ensuring the morphological uniformity of the subsequently formed metal grid lines 300.
[0071] In some embodiments, a coating apparatus 400 is used to coat the non-gateline areas of the metal seed layer 110 with liquid paraffin. Please refer to [reference needed]. Figure 6 As shown, the coating apparatus 400 includes a printing platform 410, a printing screen 420, and a screen squeegee 430. Step S13 specifically includes steps S131 to S133:
[0072] Step S131: First, place the solar cell substrate 100 on the printing platform 410, and then cover the solar cell substrate 100 placed on the printing platform 410 with the printing screen 420.
[0073] Step S132: Liquid paraffin is coated onto a printing screen 420 covering the solar cell substrate 100.
[0074] In step S133, the squeegee 430 is moved against the upper surface of the printing screen 420 coated with liquid paraffin, so that the liquid paraffin is applied through the printing screen 420 to the non-grid area of the metal seed layer 110.
[0075] Please refer to the following: Figure 7 As shown, the printing screen 420 has a cutout area 421 and a non-cutout area 422. The cutout area 421 corresponds to the non-grid area, and the non-cutout area 422 corresponds to the grid area. Therefore, liquid paraffin can be applied to the non-grid area of the metal seed layer 110 through the cutout area 421, thereby forming a first paraffin layer 200 with patterned grooves 210 on the metal seed layer 110, and the grid area of the metal seed layer 110 is exposed in the patterned grooves 210.
[0076] In this embodiment, the first paraffin layer 200 with patterned grooves 210 can be formed by the coating device 400, which is not only simple but also low in cost.
[0077] As one implementation method, please refer to Figure 6As shown, the coating apparatus 400 may further include a feeding track 440 and a pre-cooling assembly 450. The feeding track 440 is used to transport the solar cell substrate 100 to the printing platform 410. The pre-cooling assembly 450 is disposed above the feeding track 440, and the pre-cooling assembly 450 is spaced apart from the feeding track 440, so that the solar cell substrate 100 can pass under the pre-cooling assembly 450. During the process of the solar cell substrate 100 being transported to the printing platform 410 via the feeding track 440, the pre-cooling assembly 450 pre-cools the solar cell substrate 100 on the feeding track 440. That is to say, the pre-cooling treatment in step S12 can be completed at the same time as feeding, which can effectively shorten the process time and improve production efficiency.
[0078] As an example, the pre-cooling component 450 can be a cold air duct.
[0079] As one implementation method, please refer to Figure 6 As shown, the coating apparatus 400 may also include a discharge track 460 for conveying the coated solar cell substrate 100 to the next station.
[0080] In some embodiments, after step S13, the preparation method further includes step S15:
[0081] Step S15: Perform a first drying treatment on the first paraffin layer 200 to solidify the first paraffin layer 200.
[0082] In this embodiment, the first drying process on the first paraffin layer 200 can further accelerate the solidification of the first paraffin layer 200, making the morphology of the patterned groove 210 more stable, avoiding deformation of the first paraffin layer 200 in subsequent processes, thereby further ensuring the morphology of the subsequently formed metal grid line 300.
[0083] As one implementation, the temperature of the first drying process is 20°C to 30°C. Exemplarily, the temperature of the first drying process can be, but is not limited to, 20°C, 22°C, 23°C, 25°C, 26°C, 29°C, or 30°C.
[0084] In one implementation, the duration of the first drying process is 3 to 5 minutes. Exemplarily, the duration of the first drying process can be, but is not limited to, 3 minutes, 3.5 minutes, 4 minutes, or 5 minutes.
[0085] In some embodiments, after step S13, the preparation method further includes step S16:
[0086] Step S16: The solar cell substrate 100 having the first paraffin layer 200 is edge-wrapped.
[0087] As one implementation method, step S16 specifically includes step S161:
[0088] Step S161: Apply liquid paraffin to the edge of the solar cell substrate 100 for edge banding treatment, so as to form a second paraffin layer on the edge of the solar cell substrate 100 having the first paraffin layer 200.
[0089] In this embodiment, liquid paraffin is used to wrap the edges of the solar cell substrate 100, which can further reduce the process cost. Furthermore, when the first paraffin layer 200 is removed in the subsequent process, the second paraffin layer can be removed at the same time, which further simplifies the process flow.
[0090] In one implementation, after step S161, step S16 may further include step S162:
[0091] Step S162: Perform a second drying treatment on the second paraffin layer to cure the second paraffin layer.
[0092] As an example, the temperature of the second drying process is 20°C to 30°C. Exemplarily, the temperature of the second drying process can be, but is not limited to, 20°C, 22°C, 23°C, 25°C, 26°C, 29°C, or 30°C.
[0093] As an example, the duration of the second drying process is 1 min to 2 min. Exemplarily, the duration of the second drying process can be, but is not limited to, 1 min, 1.5 min, or 2 min.
[0094] In other embodiments, step S16 may specifically include: wrapping the edge of the solar cell substrate 100 with edge-sealing adhesive.
[0095] Step S14: Electroplating is performed to form metal grid lines 300 within the patterned groove 210. Please refer to [reference needed]. Figure 4 As shown.
[0096] In some embodiments, step S14 may specifically include: electroplating the metal grid line 300 in a copper sulfate electroplating solution. The metal grid line 300 may be a copper grid line. Exemplarily, the height of the metal grid line 300 may be controlled between 8 μm and 14 μm.
[0097] In some embodiments, after step S14, the preparation method further includes step S17:
[0098] Step S17, remove the first paraffin layer 200, please refer to... Figure 5 As shown.
[0099] It is understandable that if the preparation method includes step S161, in step S17, the second paraffin layer can be removed at the same time as the first paraffin layer 200 is removed, thereby further simplifying the process and improving production efficiency.
[0100] In one implementation, step S17 may specifically include steps S171 to S172:
[0101] Step S171: Heat the first paraffin layer 200 to melt it.
[0102] As an example, the first paraffin layer 200 can be heated using a hot air gun.
[0103] It is understandable that if the preparation method includes step S161, when the first paraffin layer 200 is heated in step S171, the second paraffin layer can also be heated, thereby further simplifying the process and improving production efficiency.
[0104] As an example, the heat treatment temperature is 60°C to 80°C. For example, the heat treatment temperature can be, but is not limited to, 60°C, 65°C, 70°C, 75°C, or 80°C.
[0105] As an example, the heating treatment time is 1 min to 2 min. For example, the heating treatment time can be, but is not limited to, 1 min, 1.5 min or 2 min.
[0106] Step S172: The melted first paraffin layer 200 is rinsed to remove the first paraffin layer 200.
[0107] As an example, the first paraffin layer 200 after melting can be rinsed with hot water.
[0108] It is understandable that if the preparation method includes step S161, in step S172, when the melted first paraffin layer 200 is rinsed, the melted second paraffin layer can also be rinsed, thereby further simplifying the process and improving production efficiency.
[0109] As an example, the rinsing temperature is 60°C to 70°C. For example, the rinsing temperature can be, but is not limited to, 60°C, 62°C, 65°C, 66°C, 68°C, or 70°C.
[0110] As an example, the rinsing process takes 20 to 40 seconds. For instance, the rinsing process can take, but is not limited to, 20 seconds, 22 seconds, 25 seconds, 27 seconds, 30 seconds, 33 seconds, 35 seconds, 37 seconds, or 40 seconds.
[0111] In this embodiment, the first paraffin layer 200, or the first paraffin layer 200 and the second paraffin layer, are first heated and melted, and then the melted paraffin is rinsed clean. Since paraffin has a lower density than water, the paraffin washed into the water floats on the surface, making it easy to collect. After evaporating and cooling the collected paraffin, solid paraffin is obtained. The melting point of solid paraffin is 50℃~65℃. After melting the obtained solid paraffin into liquid paraffin, it can be reused in step S13, or steps S13 and S16, thus allowing for multiple recycling of paraffin, reducing raw material consumption, and significantly saving costs.
[0112] One embodiment of this application also provides a solar cell, which is prepared using the solar cell preparation method provided in any of the above embodiments.
[0113] The present application will be further described below through specific embodiments.
[0114] Example 1
[0115] This embodiment provides a method for fabricating a solar cell, including the following steps:
[0116] Step 1-1: The silicon substrate 120 is texturized and cleaned to form a uniform "positive pyramid" textured surface on its surface. The silicon substrate 120 is an N-type single-crystal silicon wafer, and the base size of the pyramid structure of the textured surface is 2μm to 8μm.
[0117] In steps 1-2, a first intrinsic amorphous silicon layer 130 and an N-type doped amorphous silicon layer 150 are sequentially deposited on the upper surface of the texturized silicon substrate 120 using a PECVD plasma deposition equipment. A second intrinsic amorphous silicon layer 140 and a P-type doped amorphous silicon layer 160 are sequentially deposited on the lower surface of the texturized silicon substrate 120 using the same PECVD equipment. The thickness of the first intrinsic amorphous silicon layer 130 can be 3 nm to 6 nm, the thickness of the second intrinsic amorphous silicon layer 140 can be 3 nm to 9 nm, the thickness of the N-type doped amorphous silicon layer 150 can be 5 nm to 10 nm, and the thickness of the P-type doped amorphous silicon layer 160 can be 5 nm to 15 nm.
[0118] Steps 1-3 involve depositing a first conductive layer 170 and a second conductive layer 180 on an N-type doped amorphous silicon layer 150 and a P-type doped amorphous silicon layer 160, respectively, using a PVD magnetron sputtering apparatus. The first conductive layer 170 and the second conductive layer 180 are both ITO transparent conductive films, with thicknesses ranging from 90 nm to 110 nm.
[0119] Steps 1-4 involve depositing copper seed layers on the first conductive layer 170 and the second conductive layer 180 using a PVD magnetron sputtering apparatus. The thickness of the copper seed layer is 100 nm to 250 nm.
[0120] Steps 1-5 involve pre-cooling the solar cell substrate 100. The pre-cooling temperature is 0℃~10℃, and the pre-cooling time is 0.5S~3S.
[0121] Steps 1-6 involve coating the non-grid area of the copper seed layer with liquid paraffin to form a first paraffin layer 200 with patterned grooves 210. The liquid paraffin comprises 1% to 10% by mass of expanded graphite, and the thickness of the first paraffin layer 200 is 8 μm to 14 μm.
[0122] Steps 1-7 involve subjecting the first paraffin layer 200 to a first drying treatment to solidify it. The temperature of the first drying treatment is 20℃~30℃, and the duration of the first drying treatment is 3min~5min.
[0123] Steps 1-8: Apply liquid paraffin to the edge of the solar cell substrate 100 for edge banding treatment, so as to form a second paraffin layer on the edge of the solar cell substrate 100 having the first paraffin layer 200.
[0124] Steps 1-9 involve a second drying treatment to solidify the second paraffin layer. The temperature for this second drying treatment is 20℃~30℃, and the drying time is 1min~2min.
[0125] Steps 1-10 involve electroplating copper grid lines in a copper sulfate plating solution. The height of the copper grid lines is controlled between 8 μm and 14 μm.
[0126] Steps 1-11: First, the first paraffin layer 200 and the second paraffin layer are heated to melt them. Then, the melted first paraffin layer 200 and the second paraffin layer are rinsed to remove them from the solar cell substrate 100. Finally, the copper seed layer in the non-grid area is removed in a dilute sulfuric acid solution.
[0127] Steps 1-12: First, collect the washed paraffin wax, then evaporate and cool the paraffin wax to obtain solid paraffin wax, and then melt the solid paraffin wax to obtain the liquid paraffin wax to be coated in steps 1-6 and 1-8.
[0128] In this embodiment, pre-cooling the solar cell substrate 100 before coating can shorten the curing time of the liquid paraffin. This not only shortens the process time but also ensures that the liquid paraffin on both sides of the patterned groove 210 retains its shape after curing, preventing collapse. This results in a uniform and rectangular morphology of the first paraffin layer 200 on both sides of the patterned groove 210, laying a good foundation for the subsequent formation of the metal grid lines 300 and improving the yield and efficiency of the solar cell. The first paraffin layer 200 with the patterned groove 210 can be formed by coating alone, eliminating the need for printing and developing. This saves on printing equipment, developing equipment, and the chemicals required for developing, effectively simplifying the process and reducing costs. Furthermore, since the patterned groove 210 can be formed simply by coating in this embodiment, the grid line area of the copper seed layer is directly exposed in the patterned groove 210, eliminating the need for development or other processing to form the patterned groove 210. Therefore, there is no residual first paraffin layer 200 at the bottom of the patterned groove 210, ensuring the bonding force between the copper grid line and the copper seed layer, and improving the yield and efficiency of the solar cell. Moreover, the first drying treatment of the first paraffin layer 200 can further accelerate the solidification of the first paraffin layer 200, making the morphology of the patterned groove 210 more stable and further preventing the first paraffin layer 200 from deforming in subsequent processes, thereby further ensuring the morphology of the subsequently formed metal grid line 300. In addition, using liquid paraffin to edge-wrap the solar cell substrate 100 can further reduce process costs. When removing the first paraffin layer 200, the second paraffin layer is removed simultaneously, further simplifying the process flow. In addition, this embodiment also recycles paraffin, reducing raw material consumption and greatly saving costs.
[0129] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0130] The above embodiments merely illustrate preferred implementations of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims.
Claims
1. A method for fabricating a solar cell, characterized in that, include: A solar cell substrate is provided, the surface of which has a metal seed layer; The solar cell substrate is pre-cooled. Liquid paraffin is applied to the non-grid area of the metal seed layer of the solar cell substrate after pre-cooling treatment to form a first paraffin layer with patterned grooves. Metal grid lines are formed by electroplating within the patterned grooves.
2. The method for preparing a solar cell as described in claim 1, characterized in that, The precooling treatment satisfies at least one of the following (i) to (ii): (i) The temperature of the precooling treatment is 0℃~10℃; (ii) The duration of the precooling process is 0.5S to 3S.
3. The method for preparing a solar cell as described in claim 1, characterized in that, The liquid paraffin comprises 1% to 10% by mass of expanded graphite.
4. The method for preparing a solar cell as described in claim 1, characterized in that, Liquid paraffin is applied to the non-grid area of the metal seed layer using a coating device, which includes a printing platform, a printing screen, and a screen squeegee. The method of applying liquid paraffin to the non-gateline areas of the metal seed layer using a coating device includes: The printing screen is applied to the upper surface of the solar cell substrate placed on the printing platform; The liquid paraffin is coated onto a printing screen covering the upper surface of the solar cell substrate; The squeegee is moved against the upper surface of the printing screen coated with the liquid paraffin, so that the liquid paraffin is applied through the printing screen to the non-grid area of the metal seed layer.
5. The method for preparing a solar cell as described in claim 1, characterized in that, After forming the first paraffin layer with patterned grooves, the method further includes performing a first drying treatment on the first paraffin layer to solidify the first paraffin layer. The first drying process satisfies at least one of the following (iii) to (iv): (iii) The temperature of the first drying treatment is 20℃~30℃; (iv) The duration of the first drying process is 3 min to 5 min.
6. The method for preparing a solar cell as described in claim 1, characterized in that, After forming the first paraffin layer with patterned grooves, the method further includes: Liquid paraffin is applied to the edge of the solar cell substrate for edge banding to form a second paraffin layer at the edge of the solar cell substrate.
7. The method for preparing a solar cell as described in claim 6, characterized in that, After forming the second paraffin layer at the edge of the solar cell substrate, the process further includes performing a second drying treatment on the second paraffin layer. The second drying process satisfies at least one of the following (v) to (vi): (v) The temperature of the second drying treatment is 20°C to 30°C; (vi) The duration of the second drying process is 1 min to 2 min.
8. The method for preparing a solar cell as described in claim 1, characterized in that, After electroplating to form metal grid lines within the patterned groove, the process further includes: The first paraffin layer is heated to melt it. The first layer of paraffin wax is rinsed off to remove it.
9. The method for preparing a solar cell as described in claim 8, characterized in that, The heat treatment satisfies at least one of the following (vii) to (viii), and / or the rinsing treatment satisfies at least one of the following (ix) to (x): (vii) The temperature of the heat treatment is 60℃~80℃; (viii) The duration of the heat treatment is 1 min to 2 min; (ix) The rinsing temperature is 60℃~70℃; (x) The duration of the rinsing process is 20S to 40S.
10. A solar cell, characterized in that, The solar cell is obtained by the method described in any one of claims 1-9.