Solar cell preparation method, solar cell and photovoltaic module
By depositing a film layer on the back of the monocrystalline silicon substrate of IBC solar cells and opening P and N regions using tunneling technology, the problems of complex and high cost of boron diffusion process in the prior art are solved, and process simplification and Cost is reduced, while improving photoelectric conversion efficiency.
Patent Information
- Application Number
- CN202310799901.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-30
- Publication Date
- 2024-12-31
AI Technical Summary
Boron diffusion is required during the preparation of existing IBC solar cells, which is complex in the process and high in production costs.
By depositing silicon-based oxides and polysilicon film layers on the back of the single crystal silicon substrate, and opening P and N regions on the substrate using tunneling technology, the boron diffusion process is avoided and the production process is simplified.
The production process of solar cells is simplified, the production cost is reduced, and the photoelectric conversion efficiency is improved.
Smart Images
Figure CN119230649A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of photovoltaic technology, and in particular to a method for preparing a solar cell, a solar cell and a photovoltaic module. Background Art
[0002] Interdigitated Back Contact (IBC), also known as full back electrode contact crystalline silicon solar cells, has no grid lines on the front, and the positive and negative metal grid lines on the back are arranged in a finger-like cross pattern. This structural design avoids the metal grid line electrode from blocking the light, and the front and back surfaces of the IBC cell both use a pyramid structure and an anti-reflection layer, which can maximize the use of incident light. Compared with the existing Passivated Emitter and Rear Cell (PERC) cells, the optical loss is small and the photoelectric conversion efficiency is high.
[0003] However, in the preparation process of existing IBC batteries, it is necessary to form P and N regions on the film layer through boron diffusion, which has a complicated process and difficult processing, and the production cost of IBC batteries is high. Summary of the invention
[0004] The present application provides a solar cell preparation method, a solar cell and a photovoltaic module, aiming to solve the problem that the IBC cell preparation process in the prior art involves diffusion steps such as boron diffusion, and the preparation is complex and the production cost is high.
[0005] In a first aspect, the present application provides a method for preparing a solar cell, comprising:
[0006] Depositing a silicon-based oxide and a phosphorus-containing polysilicon film layer on the back side of a single crystal silicon substrate to obtain a first intermediate product;
[0007] Performing a tunneling junction operation on the back side of the first intermediate product according to a preset tunneling junction pattern to obtain a second intermediate product, wherein the tunneling junction pattern is used for a tunneling junction device to open an N region and a P region on the back side of the first intermediate product;
[0008] Depositing the silicon-based oxide and the nitrogen-containing polysilicon film layer on the back side of the second intermediate product to obtain a third intermediate product;
[0009] Depositing a silicon nitride film layer on the back side of the third intermediate product to obtain a fourth intermediate product;
[0010] The solar cell is prepared by sintering the fourth intermediate product.
[0011] Optionally, the solar cell preparation provided in the present application further includes:
[0012] Depositing the silicon-based oxide on the back side of the single crystal silicon substrate to obtain a first deposition result;
[0013] The phosphorus-containing polysilicon film layer is deposited on the back side of the first deposition result to obtain the first intermediate product.
[0014] Optionally, the solar cell preparation provided in the present application further includes:
[0015] The first deposition result is obtained by depositing the silicon-based oxide onto the back side of the single crystal silicon substrate through low pressure chemical vapor deposition.
[0016] Optionally, the solar cell preparation provided in the present application further includes:
[0017] Performing a laser film opening action on the back side of the first intermediate product according to a preset first laser pattern to obtain a first film opening result, wherein the first laser pattern is used for a laser emitting device to open an N region on the back side of the first intermediate product;
[0018] Depositing a silicon nitride film layer on the back side of the first film opening result to obtain a fifth intermediate product;
[0019] The second intermediate product is obtained by performing a laser film opening action on the back side of the fifth intermediate product according to a preset second laser pattern, wherein the second laser pattern is used for the laser emitting device to open a P area on the back side of the fifth intermediate product.
[0020] Optionally, the solar cell preparation provided in the present application further includes:
[0021] Performing a tunneling junction operation on the back of the first intermediate product according to a preset first screen printing pattern to obtain a first film opening result, wherein the first screen printing pattern is used for a tunneling junction device to open an N region on the back of the first intermediate product;
[0022] Depositing a silicon nitride film layer on the back side of the first film opening result to obtain a sixth intermediate product;
[0023] The second intermediate product is obtained by performing a tunneling junction action on the back side of the sixth intermediate product according to a preset second screen-printed pattern, wherein the second screen-printed pattern is used for the tunneling junction device to open a P region on the back side of the fifth intermediate product.
[0024] Optionally, the solar cell preparation provided in the present application further includes:
[0025] A laser film opening action is performed on the back side of the fourth intermediate product according to a preset third laser pattern to obtain a fourth intermediate product after laser film opening, wherein the third laser pattern is used for the laser emitting device to form a silicon nitride isolation region on the back side of the fourth intermediate product.
[0026] Optionally, the solar cell preparation provided in the present application further includes:
[0027] Screen printing the fourth intermediate product with positive and negative electrode slurries to obtain a screen-printed intermediate product;
[0028] The screen-printed intermediate product is sintered to prepare the solar cell.
[0029] In a second aspect, the present application provides a solar cell, which is prepared by any one of the solar cell preparation methods of the first aspect, comprising: a single crystal silicon substrate and a film layer structure located on the back side of the single crystal silicon substrate;
[0030] The back film layer structure comprises: a silicon-based oxide film layer, a phosphorus-containing polysilicon film layer, a first silicon nitride film layer, a nitrogen-containing polysilicon film layer, a second silicon nitride film layer and a screen-printed film layer which are stacked in sequence.
[0031] Optionally, in the solar cell provided in the present application, the thickness of the first silicon nitride film layer is 5 nm to 60 nm;
[0032] The second silicon nitride film layer has a thickness of 50 nm to 120 nm.
[0033] In a third aspect, the present application provides a photovoltaic assembly comprising a plurality of solar cells described in the present application.
[0034] In the solar cell preparation method provided in the present application, a silicon-based oxide and a polycrystalline silicon film layer are deposited twice on the back side of a substrate, and a second intermediate product is obtained by a tunnel junction method according to a preset laser pattern. Since P and N regions can be opened on a single crystal silicon substrate by deposition and tunnel junction methods, the existing boron diffusion processing technology is avoided, the solar cell production process is simplified, and the solar cell production cost is reduced.
[0035] The above description is only an overview of the technical solution provided by the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0037] Figure 1 This is one of the schematic diagrams of the solar cell preparation method provided in the embodiment of the present application;
[0038] Figure 2 This is the second schematic diagram of the solar cell preparation method provided in the embodiment of the present application;
[0039] Figure 3 This is the third schematic diagram of the solar cell preparation method provided in the embodiment of the present application;
[0040] Figure 4 This is the fourth schematic diagram of the solar cell preparation method provided in the embodiment of the present application;
[0041] Figure 5 This is the fifth schematic diagram of the solar cell preparation method provided in the embodiment of the present application;
[0042] Figure 6 This is the sixth schematic diagram of the solar cell preparation method provided in the embodiment of the present application;
[0043] Figure 7 This is the seventh schematic diagram of the solar cell preparation method provided in the embodiment of the present application;
[0044] Figure 8 This is one of the schematic diagrams of the solar cell structure provided in the embodiment of the present application;
[0045] Fig. 9 This is the second schematic diagram of the solar cell structure provided in the embodiment of the present application;
[0046] Fig.10 This is the third schematic diagram of the solar cell structure provided in the embodiment of the present application;
[0047] Fig.11 This is the fourth schematic diagram of the solar cell structure provided in the embodiment of the present application;
[0048] Fig.12 This is the fifth schematic diagram of the solar cell structure provided in the embodiment of the present application;
[0049] Fig.13 This is the sixth schematic diagram of the solar cell structure provided in the embodiment of the present application;
[0050] Fig.14 This is the seventh schematic diagram of the solar cell structure provided in the embodiment of the present application;
[0051] Fig.15 This is the eighth schematic diagram of the solar cell structure provided in the embodiment of the present application;
[0052] Fig.16 This is the ninth schematic diagram of the solar cell structure provided in the embodiments of the present application. DETAILED DESCRIPTION
[0053] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0054] The first embodiment of the present application provides a method for preparing a solar cell, such as Figure 1 As shown, including:
[0055] Step 101, depositing a silicon-based oxide and a phosphorus-containing polysilicon film layer on the back side of a single crystal silicon substrate to obtain a first intermediate product;
[0056] Step 102: performing a tunneling junction operation on the back side of the first intermediate product according to a preset tunneling junction pattern to obtain a second intermediate product, wherein the tunneling junction pattern is used for a tunneling junction device to open an N region and a P region on the back side of the first intermediate product;
[0057] Step 103, depositing the silicon-based oxide and the nitrogen-containing polysilicon film layer on the back side of the second intermediate product to obtain a third intermediate product;
[0058] Step 104, depositing a silicon nitride film layer on the back side of the third intermediate product to obtain a fourth intermediate product;
[0059] Step 105: Prepare a solar cell by sintering the fourth intermediate product.
[0060] Specifically, the solar cells prepared in this application are mainly IBC cells. The IBC cells have no grid lines on the front, and the positive and negative metal grid lines on the back are arranged in a finger-like cross pattern, which maximizes the use of incident light and has high photoelectric conversion efficiency. The solar cells prepared in this application are not limited to the type of single-crystal silicon substrate, and can be N-type substrates or P-type substrates. Considering the service life, N'-type substrate single-crystal silicon is used as an example for description.
[0061] Before preparing solar cells according to the preparation provided in this application, it is necessary to perform double-sided texturing on the monocrystalline silicon substrate so that a velvet surface is formed on the surface of the monocrystalline silicon substrate. Subsequently, an oxide film is formed on the velvet surface of the monocrystalline silicon substrate, for example, by high-temperature double-sided oxidation on the monocrystalline silicon substrate through equipment such as a tube furnace, to form an oxide film of silicon oxide or silicon nitride or silicon oxynitride, and the thickness of the oxide film can be set to 50-100nm. Afterwards, the back side of the monocrystalline silicon substrate is polished, for example, by using a chain trough device to polish the back side of the monocrystalline silicon substrate with an alkaline solution.
[0062] After pre-processing the single crystal silicon substrate, silicon oxide SiOx and phosphorus-containing polysilicon film layer poly-Si (p+) are first deposited on the back of the polished single crystal silicon substrate to obtain a first intermediate product having a SiOx film layer and a poly-Si (p+) film layer in sequence on the back. Then, an N region and a P region are opened on the back of the first intermediate product according to a pre-set tunneling junction pattern or a laser pattern by means of a tunneling junction to obtain a second intermediate product.
[0063] Afterwards, silicon oxide SiOx and a nitrogen-containing polysilicon film layer poly-Si(N+) are deposited on the back side of the second intermediate product with the P and N regions opened to obtain a third intermediate product with a SiOx film layer and a poly-Si(N+) film layer added to the back side based on the second intermediate product.
[0064] Subsequently, a silicon nitride film layer is deposited on the poly-Si (N+) film layer of the third intermediate product to obtain a fourth intermediate product, and a government electrode slurry is printed based on the third intermediate product, and then sintered to prepare a cell, i.e., a solar cell.
[0065] In the solar cell preparation method provided in the present application, silicon-based oxide and polysilicon film layers are deposited twice on the back of the substrate, and a second intermediate product is obtained by a tunnel junction method according to a preset laser pattern. The second intermediate product can open the P region and the N region without diffusion. Compared with the existing solar cell preparation method, it is necessary to print a layer of boron-containing interdigitated diffusion mask layer on the back of the battery. The boron on the mask layer enters the N-type single crystal silicon substrate after diffusion to form the P region, and the area where the mask layer is not printed forms the N region after phosphorus diffusion. The diffusion action simplifies the solar cell production action and reduces the production cost of solar cells.
[0066] It should be emphasized that in the solar cell preparation method provided by the present application, the preparation action on the front side of the single crystal silicon substrate is similar to that of the prior art. The present application mainly prepares the P and N regions arranged in finger-like cross-spaces on the back side of the single crystal silicon substrate by means of tunnel junction, which saves the process of generating the P and N regions by diffusion and reduces the preparation cost of solar cells.
[0067] In the implementation mode of the present application, Figure 2 As shown, in the method for preparing a solar cell, step 101 includes:
[0068] Step 111, depositing the silicon-based oxide on the back side of the single crystal silicon substrate to obtain a first deposition result;
[0069] Step 112: depositing the phosphorus-containing polysilicon film layer on the back side of the first deposition result to obtain the first intermediate product.
[0070] Specifically, in the solar cell preparation method provided in the present application, the method of adding a SiOx film layer and a poly-Si (P+) film layer on the pre-treated single crystal silicon substrate includes but is not limited to the following methods:
[0071] First, SiOx is deposited on the back of the pre-treated single crystal silicon substrate, that is, the back of the IBC cell where the P region and the N region need to be opened, to obtain a first deposition result including a SiOx film layer. Then, poly-Si (P+) is deposited on the SiOx film layer of the first deposition result to obtain a first intermediate product in which a SiOx film layer and a poly-Si (P+) film layer are sequentially deposited on the single crystal silicon substrate.
[0072] It should be emphasized that in the solar cell preparation method provided in the present application, the SiOx film layer and the poly-Si (P+) film layer can be deposited on the single crystal silicon substrate by double-sided deposition, or the SiOx film layer and the poly-Si (P+) film layer can be deposited on the single crystal silicon substrate by single back side deposition, and the present application does not impose any restrictions.
[0073] In the implementation manner of the present application, a SiOx film layer is formed on the back side of a single crystal silicon substrate by a surface treatment method of deposition, thereby avoiding the need for boron diffusion to form N and P regions in existing IBC battery processing, reducing production difficulty and saving production costs.
[0074] In the implementation mode of the present application, Figure 3 As shown, in the method for preparing a solar cell, step 111 includes:
[0075] Step 113: depositing the silicon-based oxide onto the back side of the single crystal silicon substrate by low pressure chemical vapor deposition to obtain the first deposition result.
[0076] Specifically, in the solar cell preparation method provided in the present application, the back side of the polished single crystal silicon substrate can be surface treated by, but not limited to, low pressure chemical vapor deposition (LPCVD) and other vapor deposition methods to obtain a SiOx film layer. In addition, a poly-Si (P+) film layer can also be deposited on the SiOx film layer of the first deposition result by LPCVD.
[0077] In the implementation mode of the present application, Figure 4 As shown, the tunnel junction pattern is a laser pattern. In the method for preparing a solar cell, step 102 includes:
[0078] Step 121, performing a laser film opening action on the back side of the first intermediate product according to a preset first laser pattern to obtain a first film opening result, wherein the first laser pattern is used for a laser emitting device to open an N region on the back side of the first intermediate product;
[0079] Step 122, depositing a silicon nitride film layer on the back side of the first film opening result to obtain a fifth intermediate product;
[0080] Step 123, performing a laser film opening operation on the back side of the fifth intermediate product according to a preset second laser pattern to obtain the second intermediate product, wherein the second laser pattern is used for the laser emitting device to open a P region on the back side of the fifth intermediate product.
[0081] Specifically, in the solar cell preparation method provided in the present application, the tunnel junction pattern used to control the laser to open the P region and the N region in the single crystal silicon substrate is a laser pattern, and an area is opened on the back side of the single crystal silicon substrate in a patterned manner by laser formation.
[0082] First, according to the preset first laser pattern, laser film opening is performed on the back of the first intermediate product, and the SiOx film layer and poly-Si (P+) film layer in the single crystal silicon substrate area corresponding to the first laser pattern are removed by laser. The design shape of the first laser pattern is consistent with the shape of the N area to be opened in the single crystal silicon substrate, which is used to guide the laser emitting device to emit laser and form the N area of the solar cell on the back of the first intermediate product.
[0083] Subsequently, a silicon nitride film layer is deposited on the back of the first film opening result in which the N region is opened, for example, a silicon nitride film layer for isolation is formed on the first film opening result in which the N region is opened by plasma enhanced chemical vapor deposition (PECVD). The thickness of the silicon nitride film layer or the first silicon nitride film layer is set according to the isolation requirements of the poly-Si (P+) film layer and the poly-Si (N+) film layer, for example, 5nm to 60nm, to obtain a fifth intermediate product.
[0084] Finally, according to the preset second laser pattern, laser film opening is performed on the back of the fifth intermediate product, and the film layer in the single crystal silicon substrate area corresponding to the second laser pattern is removed by laser. The design shape of the second laser pattern is consistent with the shape of the P area to be opened in the single crystal silicon substrate, which is used to guide the laser emitting device to emit laser and form the P area of the solar cell on the back of the fifth intermediate product.
[0085] In an embodiment of the present application, the tunnel junction pattern can be a laser composition pattern, thereby ensuring that during the laser tunnel junction processing step, the single crystal silicon substrate on which the SiOx film layer and the poly-Si (P+) film layer are formed can be processed according to the laser composition pattern, thereby obtaining the P region and N region of the IBC battery, reducing the processing difficulty of the IBC battery and saving the production cost of the IBC battery.
[0086] In the implementation mode of the present application, Figure 5 As shown, the tunnel junction pattern is a screen-printed pattern. In the solar cell preparation method, step 102 includes:
[0087] Step 124, performing a tunneling junction operation on the back side of the first intermediate product according to a preset first screen printing pattern to obtain a first film opening result, wherein the first screen printing pattern is used for a tunneling junction device to open an N region on the back side of the first intermediate product;
[0088] Step 125, depositing a silicon nitride film layer on the back side of the first film opening result to obtain a sixth intermediate product;
[0089] Step 126, performing a tunneling junction operation on the back side of the sixth intermediate product according to a preset second screen-printed pattern to obtain the second intermediate product, wherein the second screen-printed pattern is used for the tunneling junction device to open a P region on the back side of the sixth intermediate product.
[0090] Specifically, in the solar cell preparation method provided in the present application, the tunnel junction pattern used to control the laser to open the P region and the N region in the single crystal silicon substrate is a screen printing pattern, which is formed by etching slurry and screen printing.
[0091] First, laser film opening is performed on the back of the first intermediate product according to the pre-set first screen printing pattern, and the SiOx film layer and poly-Si (P+) film layer in the single crystal silicon substrate area corresponding to the first screen printing pattern are removed by laser. The design shape of the first screen printing pattern is consistent with the shape of the N area to be opened in the single crystal silicon substrate, which is used to guide the laser emitting device to emit laser and form the N area of the solar cell on the back of the first intermediate product.
[0092] Subsequently, a silicon nitride film layer is deposited on the back of the first film opening result of the N region, for example, a silicon nitride film layer for isolation is formed on the first film opening result of the N region by PECVD. The thickness of the silicon nitride film layer or the first silicon nitride film layer is set according to the isolation requirements of the poly-Si (P+) film layer and the poly-Si (N+) film layer, for example, 5nm to 60nm, to obtain a sixth intermediate product.
[0093] Finally, according to the preset second screen printing pattern, laser film opening is performed on the back of the sixth intermediate product, and the film layer in the single crystal silicon substrate area corresponding to the second screen printing pattern is removed by laser. The design shape of the second screen printing pattern is consistent with the shape of the P area to be opened in the single crystal silicon substrate, which is used to guide the laser emitting device to emit laser and form the P area of the solar cell on the back of the sixth intermediate product.
[0094] In an embodiment of the present application, the tunnel junction pattern can be a pattern of etching slurry plus screen printing, thereby ensuring that during the laser tunnel junction processing step, the single crystal silicon substrate on which the SiOx film layer and the poly-Si (P+) film layer are formed can be processed according to the specific pattern of etching slurry plus screen printing, thereby obtaining the P region and N region of the IBC battery, reducing the processing difficulty of the IBC battery and saving the production cost of the IBC battery.
[0095] In the implementation mode of the present application, Figure 6 As shown, in the solar cell preparation method, after step 104 and before step 105, the method further includes:
[0096] Step 106, performing a laser film opening operation on the back side of the fourth intermediate product according to a preset third laser pattern to obtain a fourth intermediate product after laser film opening, wherein the third laser pattern is used for the laser emitting device to form a silicon nitride isolation region on the back side of the fourth intermediate product.
[0097] Specifically, after a silicon nitride film layer is deposited on the poly-Si(N+) film layer of the third intermediate product to obtain a fourth intermediate product, the poly-Si(N+) film layer is partitioned by a third laser pattern to form an isolation region separating the P region from the N region.
[0098] In the implementation manner of the present application, the third laser pattern is used for isolation processing to separate the film layer of the P region from the film layer of the N region, thereby avoiding the mixing of the P region and the N region during the subsequent printing of the electrode slurry and ensuring the product quality of the IBC battery.
[0099] In the implementation mode of the present application, Figure 7 As shown, in the method for preparing a solar cell, step 105 includes:
[0100] Step 151, screen printing the positive and negative electrode slurries on the fourth intermediate product to obtain a screen-printed intermediate product;
[0101] Step 152: sintering the screen-printed intermediate product to prepare the solar cell.
[0102] Specifically, after the fourth product on which the second silicon nitride film layer has been deposited and isolated by laser patterning is prepared, the positive and negative electrode slurries are screen-printed on the back of the fourth intermediate product, and the battery cell or solar cell is sintered.
[0103] In the embodiments of the present application, since the solar cell preparation method provided in the present application has prepared the P region and the N region by means of a tunnel junction, screen printing only needs to print the positive and negative electrode slurries to sinter and prepare the battery cells, which reduces the printing workload and improves the efficiency of solar cell preparation.
[0104] A second embodiment of the present application provides a solar cell, which is prepared by any of the solar cell preparation methods described in the first embodiment, comprising: a single crystal silicon substrate and a film layer structure located on the back side of the single crystal silicon substrate;
[0105] The back film layer structure comprises: a silicon-based oxide film layer, a phosphorus-containing polysilicon film layer, a first silicon nitride film layer, a nitrogen-containing polysilicon film layer, a second silicon nitride film layer and a screen-printed film layer which are stacked in sequence.
[0106] On the basis of the above-mentioned implementation manner, in the solar cell provided by the present application, the thickness of the first silicon nitride film layer is 5nm to 60nm; the thickness of the second silicon nitride film layer is 50nm to 120nm.
[0107] The third embodiment of the present application is combined with Figure 8-16 Provide a specific solar cell preparation process diagram:
[0108] First, the front side of the N-type monocrystalline silicon substrate of the IBC cell is passivated to obtain Figure 8 For example, an N-type single crystal silicon substrate can be textured on both sides to obtain a textured surface and then subjected to high temperature oxidation on both sides to obtain an oxide film, and then the back side is polished to obtain a pre-processed single crystal silicon substrate with a front side passivated and a back side polished. Figure 8 301 is a passivation layer after high temperature oxidation, which can be any one of silicon oxide, silicon nitride, and silicon oxynitride, and the thickness can be designed to be 50nm to 100nm according to user needs. 302 is an N-type single crystal silicon substrate, and the thickness of the N-type single crystal silicon substrate in the solar cell preparation method provided in this application is not limited.
[0109] Afterwards, silicon oxide is first deposited on the single crystal silicon substrate by the LPCVD process, and then a layer of poly-Si (p+) is deposited, so as to obtain a first intermediate product in which a SiOx film layer and a poly-Si (p+) film layer are sequentially deposited on the back side. Fig. 9 As shown, Fig. 9 308 is a SiOx film layer, and 303 is a poly-Si (p+) film layer.
[0110] Afterwards, the SiOx film layer and the poly-Si(p+) film layer are opened by laser tunneling. For example, SiOx and poly-Si(p+) in the area corresponding to the first laser pattern are removed to obtain the following: Fig.10 The first film opening result is shown. At this time, the area indicated by the arrow has been opened on the back of the first film opening result, which serves as the N area of the IBC battery.
[0111] Afterwards, a first SiNx film layer is deposited on the back of the first film opening by PECVD to obtain Fig.11 The fifth intermediate product is shown. Fig.11 The middle 304 is a first SiNx film layer or a first silicon nitride film layer, and the thickness may be 5nm to 60nm.
[0112] Afterwards, the first silicon nitride film layer is opened by laser tunneling to obtain Fig.12 The second intermediate product is shown. Fig.12 In addition to removing the first silicon nitride film layer from the N region opened by the first laser tunneling junction, a new area is opened in the first silicon nitride film layer as the P region of the IBC battery.
[0113] Afterwards, silicon oxide is first deposited on the second intermediate product by the LPCVD process, and then a layer of poly-Si(N+) is deposited, thereby obtaining a third intermediate product in which a SiOx film layer and a poly-Si(N+) film layer are sequentially deposited on the back side. Fig.13 As shown, Fig.13 The middle oblique line shaded area is the silicon oxide film layer obtained after the first and second depositions, and 305 is the poly-Si (N+) film layer. After obtaining the third intermediate product, the third intermediate product can be subjected to single-sided alkaline washing to remove the poly-Si film layer on the front side of the third intermediate product.
[0114] Then, a second SiNx film layer is deposited on the back of the third intermediate product by PECVD to obtain Fig.14 The fourth intermediate product is shown. Fig.14 The middle 306 is a second SiNx film layer or a second silicon nitride film layer, and the thickness can be 50nm to 120nm.
[0115] Afterwards, the second silicon nitride film layer corresponding to the third laser pattern is removed for the third time by means of laser tunneling junction, and the isolation between the P region and the N region is realized. Fig.15 The fourth intermediate product after laser film opening is shown. Fig.15 The second silicon nitride film layer corresponding to the third laser pattern forms a gap separating the N region and the P region, thereby ensuring blocking and isolation between various nodes.
[0116] Finally, the fourth intermediate product after laser film opening is filled with positive and negative electrode slurries through a screen printing process. The positive and negative electrode slurries are filled in the corresponding P region and N region respectively, and then sintered to obtain Fig.16 The solar cell shown. Fig.16 The black area or 306 in FIG. 3 represents the printed electrode paste coating.
[0117] It should be noted that the aforementioned solar cell and the method for preparing the solar cell, the relevant parts of the two can be referenced to each other, and can achieve the same or similar effects.
[0118] It should be noted that, for the method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present application are not limited by the described order of actions, because according to the embodiments of the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present application.
[0119] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.
[0120] It should be noted that, in this document, the terms "first", "second", etc. in the specification and claims are used to distinguish similar objects, rather than to describe a specific order or sequence. Moreover, the objects distinguished by "first", "second", etc. are usually of the same type, and the number of objects is not limited. For example, the second object can be one.
[0121] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.
[0122] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.
Claims
1. A method for preparing a solar cell, characterized in that: The method comprises: Depositing a silicon-based oxide and a phosphorus-containing polysilicon film layer on the back side of a single crystal silicon substrate to obtain a first intermediate product; Performing a tunneling junction operation on the back side of the first intermediate product according to a preset tunneling junction pattern to obtain a second intermediate product, wherein the tunneling junction pattern is used for a tunneling junction device to open an N region and a P region on the back side of the first intermediate product; Depositing the silicon-based oxide and the nitrogen-containing polysilicon film layer on the back side of the second intermediate product to obtain a third intermediate product; Depositing a silicon nitride film layer on the back side of the third intermediate product to obtain a fourth intermediate product; The solar cell is prepared by sintering the fourth intermediate product.
2. The method according to claim 1, characterized in that The step of depositing a silicon-based oxide and a phosphorus-containing polysilicon film layer on the back side of the single crystal silicon substrate to obtain a first intermediate product comprises: Depositing the silicon-based oxide on both sides of the back side of the single crystal silicon substrate to obtain a first deposition result; The phosphorus-containing polysilicon film layer is deposited on both sides of the back side of the first deposition result to obtain the first intermediate product.
3. The method according to claim 2, characterized in that Depositing silicon-based oxide on the back side of the single crystal silicon substrate to obtain a first deposition result comprises: The first deposition result is obtained by depositing the silicon-based oxide onto the back side of the single crystal silicon substrate through low pressure chemical vapor deposition.
4. The method according to claim 1, characterized in that: The tunnel junction pattern is a laser pattern, and performing a tunnel junction operation on the back side of the first intermediate product according to the preset tunnel junction pattern to obtain the second intermediate product comprises: Performing a laser film opening action on the back side of the first intermediate product according to a preset first laser pattern to obtain a first film opening result, wherein the first laser pattern is used for a laser emitting device to open an N region on the back side of the first intermediate product; Depositing a silicon nitride film layer on the back side of the first film opening result to obtain a fifth intermediate product; The second intermediate product is obtained by performing a laser film opening action on the back side of the fifth intermediate product according to a preset second laser pattern, wherein the second laser pattern is used for the laser emitting device to open a P area on the back side of the fifth intermediate product.
5. The method according to claim 1, characterized in that The tunneling junction pattern is a screen-printed pattern, and performing a tunneling junction operation on the back of the first intermediate product according to the preset tunneling junction pattern to obtain the second intermediate product comprises: Performing a tunneling junction operation on the back of the first intermediate product according to a preset first screen printing pattern to obtain a first film opening result, wherein the first screen printing pattern is used for a tunneling junction device to open an N region on the back of the first intermediate product; Depositing a silicon nitride film layer on the back side of the first film opening result to obtain a sixth intermediate product; The second intermediate product is obtained by performing a tunneling junction action on the back side of the sixth intermediate product according to a preset second screen-printed pattern, wherein the second screen-printed pattern is used for the tunneling junction device to open a P region on the back side of the sixth intermediate product.
6. The method according to claim 1, characterized in that After depositing a silicon nitride film layer on the back of the third intermediate product to obtain a fourth intermediate product, and before sintering the fourth intermediate product to prepare a solar cell, the method further includes: A laser film opening action is performed on the back side of the fourth intermediate product according to a preset third laser pattern to obtain a fourth intermediate product after laser film opening, wherein the third laser pattern is used for the laser emitting device to form a silicon nitride isolation region on the back side of the fourth intermediate product.
7. The method according to claim 1, characterized in that Sintering and preparing a solar cell according to the fourth intermediate product comprises: Screen printing the fourth intermediate product with positive and negative electrode slurries to obtain a screen-printed intermediate product; The screen-printed intermediate product is sintered to prepare the solar cell.
8. A solar cell, characterized in that: The solar cell is prepared by the method for preparing a solar cell according to any one of claims 1 to 7, comprising: a single crystal silicon substrate and a film layer structure located on the back side of the single crystal silicon substrate; The back film layer structure comprises: a silicon-based oxide film layer, a phosphorus-containing polysilicon film layer, a first silicon nitride film layer, a nitrogen-containing polysilicon film layer, a second silicon nitride film layer and a screen-printed film layer which are stacked in sequence.
9. The solar cell according to claim 8, characterized in that The thickness of the first silicon nitride film layer is 5nm to 60nm; The second silicon nitride film layer has a thickness of 50 nm to 120 nm.
10. A photovoltaic module, characterized in that: The invention comprises several solar cells as described in any one of claims 8 to 9.