A battery cell preparation process and process contact point measurement tool

Abstract

This invention discloses a battery cell manufacturing process, comprising the following steps: S1, texturing the battery cell raw material; S2, diffusion of the battery cell raw material; S3, PSG removal treatment of the battery cell; S4, oxidation treatment of the battery cell; S5, back film treatment of the battery cell; S6, front film treatment of the battery cell; S7, laser treatment of the battery cell; S8, screen printing treatment of the battery cell; a contact point measurement tool for the battery cell manufacturing process, comprising a transparent acrylic upper plate and a transparent acrylic lower plate, wherein a placement groove is formed on one side of the transparent acrylic lower plate, and several sets of contact point measurement tools are prepared. This invention achieves improved PN junction settings and provides waterproof, insulating, and aging-resistant properties; the contact point measurement tool facilitates the inspection of battery cells, allowing even inexperienced personnel to participate in the inspection, achieving the effect of improving the skills of all personnel.

Description

Technical Field

[0001] This invention belongs to the field of battery cell technology, specifically relating to a battery cell manufacturing process and a tool for measuring the contact points during the process. Background Technology

[0002] Solar cells are generally classified into monocrystalline silicon, polycrystalline silicon, and amorphous silicon. Monocrystalline silicon solar cells are currently the fastest-developing type of solar cell. Their structure and manufacturing process are well-established, and the products are widely used in space and on the ground. These solar cells use high-purity monocrystalline silicon rods as raw materials. To reduce production costs, ground-based solar cells use solar-grade monocrystalline silicon rods, with relaxed material performance specifications. Some also utilize end-and-end materials from semiconductor device processing and waste monocrystalline silicon materials, which are then re-drawn into monocrystalline silicon rods specifically for solar cells. During the production of solar cells, each processing step requires inspection to improve yield. However, various problems still exist in the production and testing of different types of solar cells on the market.

[0003] For example, the cell manufacturing process, cell manufacturing apparatus, and cell disclosed in patent announcement number CN111403555A achieve passivation treatment of the broken ends of the cell, forming an insulating layer at the broken ends. By forming an insulating layer, the broken ends of the cell are passivated, thereby removing dangling bonds, reducing surface states, reducing power loss inside the battery module, and improving the reliability of the battery module. This application also provides a cell manufacturing apparatus capable of implementing the above-mentioned cell manufacturing process; the cell manufacturing apparatus includes a dicing mechanism, a splitting mechanism, and a passivation mechanism; the dicing mechanism and the splitting mechanism cooperate to split the whole cell into several cells that meet the specifications; subsequently, the passivation mechanism performs passivation treatment on the split cells, forming an insulating layer at the broken ends of the cells. This application also provides a battery cell, which is prepared by the aforementioned battery cell preparation apparatus. The broken end of the battery cell has an insulating layer, thus the battery cell has high reliability and high conductivity. However, it does not solve the problems existing in the preparation process of existing battery cells, such as the inability to effectively improve the PN junction treatment of the space charge region, the easy reduction of the unidirectional conduction efficiency of the PN junction, the inability to prevent the penetration of water vapor and metal ions after long-term use, and the inability to perform accurate, quick and simple testing of the battery cell during the preparation and production process. Therefore, we propose a battery cell preparation process and a process contact point measurement tool. Summary of the Invention

[0004] The purpose of this invention is to provide a battery cell manufacturing process and a tool for measuring the contact points in the process, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a process for manufacturing a battery cell, comprising the following steps:

[0006] S1. Texturing process for battery cell raw materials: The battery cell raw materials are transported to the loading platform by an automatic robotic arm, and then texturing and washing operations are performed. The texturing points of the battery cell raw materials are then detected. The principle of light limiting is used to reduce light reflection, improve Isc, and increase the area of ​​the PN junction.

[0007] S2. Then, the cell material is diffused: the qualified cells after texturing are diffused and then the cells are sampled and inspected. Diffusion is used to make PN junctions. Different doping processes are used. Through diffusion, the same silicon wafer can simultaneously have P-type semiconductors and N-type semiconductors. A space charge region is formed at their interface, which is called a PN junction. The PN junction has unidirectional conductivity.

[0008] S3. PSG removal treatment for solar cells: The PSG on the surface of the solar cells is removed by washing with hydrofluoric acid solution. After the diffusion process of solar cells, a layer of PSG, which is phosphorus silicate glass, will be formed on the surface of the silicon wafer. It needs to be removed, usually by washing with hydrofluoric acid solution, to avoid short circuit of PN junction and reduction of parallel resistance.

[0009] S4. Oxidation treatment of solar cells: After the PSG is washed away, the solar cells are fed into the equipment by a robotic arm for oxidation treatment. That is, oxygen atoms combine with unsaturated silicon atoms on the silicon surface to form a SiO2 film, thereby reducing the dangling bond density on the silicon wafer surface, effectively controlling interface traps and fixing charges, and achieving the purpose of passivating the surface of solar cells.

[0010] S5. Back film treatment of solar cells: The solar cells are transported into the equipment for back film treatment to prepare a back passivation dielectric layer. This layer protects the passivation layer from the penetration of water vapor and metal ions, and provides waterproofing, insulation and aging resistance.

[0011] S6. Apply positive coating treatment to the solar cells: Using the same method as the back coating treatment, apply positive coating treatment to the solar cells to achieve excellent surface passivation effect and efficient optical anti-reflection performance;

[0012] S7. Laser processing of solar cells: Laser grooving of solar cells is performed by using a laser to drill holes or grooves on the back of the silicon wafer, exposing part of the Al2O3 and SiNx thin film layers to expose the silicon substrate. The back electric field contacts the silicon substrate through the holes or grooves on the thin film.

[0013] S8. Screen printing of the battery: The battery cell is printed with back electrode, back electric field and positive electrode. Back electrode printing provides the physical positive electrode for the final battery cell; back electric field printing is to re-dop and form a P+ layer to reduce carrier recombination and increase the turn-on voltage; positive electrode printing is to collect photocurrent and provide the physical negative electrode for the battery cell.

[0014] Preferably, the texturing process in S1 utilizes the anisotropic etching properties of silicon to etch a pyramid-like or honeycomb-like structure onto the silicon wafer surface using HF & HNO3 or KOH (NaOH);

[0015] The process of making the pile requires pre-washing, first water wash, first pile making, second pile making, second water wash, alkaline wash, third water wash, acid wash, fourth water wash and pre-washing, and finally drying.

[0016] Preferably, the diffusion in S2 uses a phosphorus oxychloride liquid source diffusion method to form an N-type layer on the silicon wafer surface, and the front and back sides are distinguished during the diffusion step.

[0017] Preferably, in step S3, the removal of PSG utilizes the reaction between HF and the P-Si glass layer on the silicon wafer surface, causing them to complex and peel off, thereby achieving a cleaning effect and realizing single-sided etching of the silicon wafer.

[0018] Preferably, in step S4, the battery cells are first subjected to alkaline polishing before oxidation. The alkaline polishing includes pre-cleaning, first water washing, alkaline polishing, second water washing, alkaline washing, third water washing, acid washing, fourth water washing, and pre-rinsing, and finally drying.

[0019] Preferably, the backsheet reaction formula in S5 is as follows:

[0020] TMA + N2O (laughing gas) → AL2O3;

[0021] PECVD deposition of ALOx+SiNx thin films;

[0022] The positive film in S6 is a SiNx antireflection film deposited by PECVD. The PECVD system is a series of generators that utilize a parallel plate coating boat and a high-frequency plasma exciter. Under low pressure and high temperature, the plasma generator stimulates silane and nitrogen to form a plasma state and react on the surface of the silicon wafer in the middle of the parallel plate coating boat. These gases are plasmaized and stored on the silicon wafer to produce silicon nitride.

[0023] A contact point measuring tool for the manufacturing process of a battery cell includes a transparent acrylic upper plate and a transparent acrylic lower plate. A first magnet is embedded at each of the four corners of the transparent acrylic upper plate, and a second magnet is embedded at each of the four corners of the upper end of the transparent acrylic lower plate. A placement groove is provided on one side of the transparent acrylic lower plate. Several sets of contact point measuring tools are prepared, each corresponding to the product processed in each step of the claim.

[0024] Preferably, a first limiting ring and a second limiting ring are respectively adhered to the four corners of the transparent acrylic upper plate and the transparent acrylic lower plate, with the first limiting ring located above the first magnet and the second limiting ring located above the second magnet.

[0025] Preferably, the four corners of the placement groove of the transparent acrylic lower plate are provided with fixed edge chamfers, and the four corners of the placement groove are provided with through holes. The front end of the placement groove is provided with a snap-on elliptical groove, and the snap-on elliptical groove is provided with snap-on holes. The upper surface of the transparent acrylic upper plate will show the key dimensions and shapes of the contact points in the process in a mapping form on the acrylic plate using spraying technology. By placing the battery cell between the transparent acrylic lower plate and the transparent acrylic upper plate, the defect location can be clearly compared with the contact point of a certain process machine in the process, directly addressing the key issues.

[0026] Preferably, the preparation process of the contact point measuring tool is as follows:

[0027] S01. Material size selection: 1:1 specification, original size A3, 420*297;

[0028] S02. The white parts of the lines should be transparent, and the lines should be clear.

[0029] S03. Two 2mm acrylic sheets are required. One of them should have UV protection applied to the front and back surfaces after the printing lines are completed to increase wear resistance.

[0030] S04, another silicon wafer requires a 183x183mm groove with a depth of 160um, and a smooth surface with good transparency;

[0031] S05. The four corners of the acrylic sheet are rounded with R5, and the machined surface is deburred to prevent scratches to operators.

[0032] S06: The four corners of the front and rear acrylic panels are equipped with magnetic closure for easy storage and organization.

[0033] S07. Title optimization: Add company logo;

[0034] S08. The contact point measuring tool will be fixed on the machine or wall. Each set needs to be equipped with 4 table plate fixing clips or glass support clips to facilitate fixing the tool and easy to pick up.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] This invention increases the area of ​​the PN junction through texturing, specifically by reducing light reflection using the light-limiting principle, increasing Isc, and thus increasing the area of ​​the PN junction. It also involves creating the PN junction through diffusion using different doping processes. Through diffusion, the same silicon wafer simultaneously possesses P-type and N-type semiconductors, forming a space charge region at their interface called the PN junction. The PN junction exhibits unidirectional conductivity. Furthermore, by preparing a back passivation dielectric layer, the passivation layer is protected against the penetration of moisture and metal ions, providing waterproofing, insulation, and aging resistance.

[0037] Furthermore, it is equipped with contact point measurement tools, which can conveniently check for internal defects, appearance defects, and mechanical performance defects in solar cells. By pinpointing the problem points in the process, it can improve the quality of defective products and enhance personnel's understanding of contact points, thereby reducing the number of defective products. This solves the current problems of low efficiency and poor timeliness in troubleshooting process issues in the photovoltaic industry, maximizes energy efficiency, improves the quality of defective products in the process, and enhances personnel's understanding of contact points. In addition, the tool thoroughly describes the morphology of silicon wafers before and after the process and the orientation of the supporting tools, so that even personnel with no experience can participate in the troubleshooting, achieving the effect of improving the skills of all employees. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the battery cell manufacturing process of the present invention;

[0039] Figure 2 This is a front view of the contact point measuring tool structure of the present invention;

[0040] Figure 3 This is a schematic diagram of the back of the contact point measuring tool structure of the present invention;

[0041] Figure 4 This is a schematic diagram of the structure of the contact point measuring tool of the present invention;

[0042] Figure 5 This is a schematic diagram of the manufacturing process of the contact point measuring tool of the present invention;

[0043] In the diagram: 1. Transparent acrylic upper plate; 101. First magnet; 102. First limiting ring; 2. Transparent acrylic lower plate; 201. Placement groove; 202. Through hole; 203. Chamfer; 204. Buckle elliptical groove; 205. Buckle hole; 206. Second magnet; 207. Second limiting ring. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Please see Figure 1 This invention provides a technical solution: a process for manufacturing battery cells, comprising the following steps:

[0046] S1. Texturing process for battery cell raw materials: The battery cell raw materials are transported to the loading platform by an automatic robotic arm, and then texturing and washing operations are performed. The texturing points of the battery cell raw materials are then detected. The principle of light limiting is used to reduce light reflection, improve Isc, and increase the area of ​​the PN junction.

[0047] S2. Then, the cell material is diffused: the qualified cells after texturing are diffused and then the cells are sampled and inspected. Diffusion is used to make PN junctions. Different doping processes are used. Through diffusion, the same silicon wafer can simultaneously have P-type semiconductors and N-type semiconductors. A space charge region is formed at their interface, which is called a PN junction. The PN junction has unidirectional conductivity.

[0048] S3. PSG removal treatment for solar cells: The PSG on the surface of the solar cells is removed by washing with hydrofluoric acid solution. After the diffusion process of solar cells, a layer of PSG, which is phosphorus silicate glass, will be formed on the surface of the silicon wafer. It needs to be removed, usually by washing with hydrofluoric acid solution, to avoid short circuit of PN junction and reduction of parallel resistance.

[0049] S4. Oxidation treatment of solar cells: After the PSG is washed away, the solar cells are fed into the equipment by a robotic arm for oxidation treatment. That is, oxygen atoms combine with unsaturated silicon atoms on the silicon surface to form a SiO2 film, thereby reducing the dangling bond density on the silicon wafer surface, effectively controlling interface traps and fixing charges, and achieving the purpose of passivating the surface of solar cells.

[0050] S5. Back film treatment of solar cells: The solar cells are transported into the equipment for back film treatment to prepare a back passivation dielectric layer. This layer protects the passivation layer from the penetration of water vapor and metal ions, and provides waterproofing, insulation and aging resistance.

[0051] S6. Apply positive coating treatment to the solar cells: Using the same method as the back coating treatment, apply positive coating treatment to the solar cells to achieve excellent surface passivation effect and efficient optical anti-reflection performance;

[0052] S7. Laser processing of solar cells: Laser grooving of solar cells is performed by using a laser to drill holes or grooves on the back of the silicon wafer, exposing part of the Al2O3 and SiNx thin film layers to expose the silicon substrate. The back electric field contacts the silicon substrate through the holes or grooves on the thin film.

[0053] S8. Screen printing of the battery: The battery cell is printed with back electrode, back electric field and positive electrode. Back electrode printing provides the physical positive electrode for the final battery cell; back electric field printing is to re-dop and form a P+ layer to reduce carrier recombination and increase the turn-on voltage; positive electrode printing is to collect photocurrent and provide the physical negative electrode for the battery cell.

[0054] In order to improve Isc, increase the area of ​​the PN junction, and achieve cleaning of the solar cell, in this embodiment, preferably, the texturing in S1 is carried out by using the anisotropic etching characteristics of silicon to etch a pyramid-like or honeycomb-like structure on the surface of the silicon wafer with HF & HNO3 or KOH (NaOH).

[0055] The process of making the pile requires pre-washing, first water wash, first pile making, second pile making, second water wash, alkaline wash, third water wash, acid wash, fourth water wash and pre-washing, and finally drying.

[0056] To achieve the fabrication of PN junctions in solar cells, different doping processes are employed. Through diffusion, the same silicon wafer can simultaneously possess both P-type and N-type semiconductors. In this embodiment, preferably, the diffusion in S2 uses a phosphorus oxychloride liquid source diffusion method to form an N-type layer on the silicon wafer surface, and during the diffusion step, the front and back sides are distinguished.

[0057] In order to clean the surface of the solar cell, in this embodiment, preferably, the PSG removal in S3 utilizes HF to react with the P-Si glass layer on the silicon wafer surface, causing it to complex and peel off, thereby achieving a cleaning effect and realizing single-sided etching of the silicon wafer.

[0058] In order to clean the dirt on the surface of the battery cells and the residue on the surface of the silicon wafer, in this embodiment, preferably, the battery cells are first subjected to alkaline polishing before oxidation in S4. The alkaline polishing includes pre-cleaning, first water washing, alkaline polishing, second water washing, alkaline washing, third water washing, acid washing, fourth water washing and pre-rinsing, and finally drying.

[0059] In order to passivate both the back film and the front film, and achieve efficient optical anti-reflection performance, in this embodiment, preferably, the back film reaction formula in S5 is as follows:

[0060] TMA + N2O (laughing gas) → AL2O3

[0061] PECVD deposition of ALOx+SiNx thin films;

[0062] The positive film in S6 is a SiNx antireflection film deposited by PECVD. The PECVD system is a series of generators that utilize a parallel plate coating boat and a high-frequency plasma exciter. Under low pressure and high temperature, the plasma generator stimulates silane and nitrogen to form a plasma state and react on the surface of the silicon wafer in the middle of the parallel plate coating boat. These gases are plasmaized and stored on the silicon wafer to produce silicon nitride.

[0063] See Figure 2-5 A contact point measuring tool for the manufacturing process of a battery cell includes a transparent acrylic upper plate 1 and a transparent acrylic lower plate 2. First magnets 101 are embedded at the four corners of the transparent acrylic upper plate 1, and second magnets 206 are embedded at the four corners of the upper end of the transparent acrylic lower plate 2. A placement groove 201 is provided on one side of the transparent acrylic lower plate 2. Several sets of contact point measuring tools are prepared, each corresponding to the product processed in each step of claim 1. The placement groove 201 facilitates the insertion and storage of battery cells.

[0064] To prevent the first rack 101 and the second magnet 206 from falling off due to attraction, a first limiting ring 102 and a second limiting ring 207 are respectively attached to the four corners of the transparent acrylic upper plate 1 and the transparent acrylic lower plate 2. The first limiting ring 102 is located above the first magnet 101, and the second limiting ring 207 is located above the second magnet 206.

[0065] To facilitate the positioning, handling, and inspection of the battery cells, the four corners of the placement groove 201 of the transparent acrylic lower plate 2 are provided with chamfered edges 203, and through holes 202 are provided at the four corners of the placement groove 201. The front end of the placement groove 201 is provided with a snap-pull elliptical groove 204, and snap-pull holes 205 are provided on the snap-pull elliptical groove 204. The upper surface of the transparent acrylic upper plate 1 uses spraying technology to present the key dimensions and shapes of the contact points in the process in a mapping form on the acrylic plate. By placing the battery cell between the transparent acrylic lower plate 2 and the transparent acrylic upper plate 1, the defect location can be clearly compared with the contact point of a certain process machine in the process, directly addressing the key issues.

[0066] In order to fabricate the contact point measuring tool, in this embodiment, the preferred fabrication process of the contact point measuring tool is as follows:

[0067] S01. Material size selection: 1:1 specification, original size A3, 420*297;

[0068] S02. The white parts of the lines should be transparent, and the lines should be clear.

[0069] S03. Two 2mm acrylic sheets are required. One of them should have UV protection applied to the front and back surfaces after the printing lines are completed to increase wear resistance.

[0070] S04, another silicon wafer requires a 183x183mm groove with a depth of 160um, and a smooth surface with good transparency;

[0071] S05. The four corners of the acrylic sheet are rounded with R5, and the machined surface is deburred to prevent scratches to operators.

[0072] S06: The four corners of the front and rear acrylic panels are equipped with magnetic closure for easy storage and organization.

[0073] S07. Title optimization: Add company logo;

[0074] S08. The contact point measuring tool will be fixed on the machine or wall. Each set needs to be equipped with 4 table plate fixing clips or glass support clips to facilitate fixing the tool and easy to pick up.

[0075] Working principle and usage process of this invention:

[0076] The first step is to texturize the battery cell raw materials: The battery cell raw materials are transported to the loading platform by an automatic robotic arm, and then texturized and washed. The texturized points of the battery cell raw materials are then detected. The principle of light limiting is used to reduce light reflection, improve Isc, and increase the area of ​​the PN junction.

[0077] The second step is to diffuse the cell raw materials: the qualified cells after texturing are diffused and then sampled for inspection. Diffusion is used to make PN junctions. Different doping processes are used to make the same silicon wafer have both P-type and N-type semiconductors through diffusion. A space charge region is formed at their interface, which is called a PN junction. The PN junction has unidirectional conductivity.

[0078] The third step is to remove the PSG from the solar cells: the PSG on the surface of the solar cells is washed away with hydrofluoric acid solution. After the diffusion process of solar cells, a layer of PSG, which is phosphorus silicate glass, will be formed on the surface of the silicon wafer. It needs to be removed, usually by washing with hydrofluoric acid solution, to avoid short circuit of PN junction and reduction of parallel resistance.

[0079] The fourth step is to oxidize the solar cells: After the PSG is washed away, the solar cells are fed into the equipment by a robotic arm for oxidation treatment. This process involves oxygen atoms combining with unsaturated silicon atoms on the silicon surface to form a SiO2 film, thereby reducing the dangling bond density on the silicon wafer surface, effectively controlling interface traps and fixing charges, and achieving the purpose of passivating the surface of the solar cell.

[0080] Step 5: Backsheet treatment of the solar cells: The solar cells are transported into the equipment for backsheet treatment to prepare a back passivation dielectric layer. This layer protects the passivation layer from the penetration of water vapor and metal ions, providing waterproofing, insulation, and aging resistance.

[0081] Step 6: Apply positive coating to the solar cells: Using the same method as the back coating treatment, apply positive coating to the solar cells to achieve excellent surface passivation and efficient optical anti-reflection performance;

[0082] Step 7: Laser processing of the solar cell: Laser grooving is performed on the solar cell. A laser is used to drill holes or grooves on the back of the silicon wafer, exposing part of the Al2O3 and SiNx thin film layers to expose the silicon substrate. The back electric field makes contact with the silicon substrate through the holes or grooves on the thin film.

[0083] Step 8: Screen printing the battery: Print the back electrode, back electric field, and positive electrode on the battery cell. The back electrode printing provides the physical positive electrode for the final battery cell; the back electric field printing is to re-dop and form a P+ layer, reduce carrier recombination, and increase the turn-on voltage; the positive electrode printing is to collect the photocurrent and provide the physical negative electrode for the battery cell.

[0084] During testing, the solar cells are placed in the placement slot 201 of the transparent acrylic lower plate 2. Then, the transparent acrylic upper plate 1 is attracted and connected by the first magnet 101 and the second magnet 206, ensuring that the transparent acrylic upper plate 1 and the transparent acrylic lower plate 2 are the same size. The key dimensions and shapes of the contact points in the process are mapped onto the acrylic plate using spraying technology on the upper surface of the transparent acrylic upper plate 1, facilitating comparative testing of the solar cells. The contact point measurement tool can conveniently identify internal defects, appearance defects, and mechanical performance defects in the solar cells. By identifying the central problem points in the process, the defective products in the process are improved, and personnel's understanding of the contact points is enhanced, thereby reducing the number of defective products. This solves the current problem of low efficiency and poor timeliness in troubleshooting process issues in the photovoltaic industry, maximizing energy efficiency. Furthermore, the tool thoroughly describes the morphology of the silicon wafer before and after the process and the orientation of the supporting tool, so that even personnel with no experience can participate in the troubleshooting, achieving the effect of improving the skills of all employees.

[0085] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for manufacturing a solar cell, characterized in that: The process includes the following steps: S1. Texturing process for battery cell raw materials: The battery cell raw materials are transported to the loading platform by an automatic robotic arm, and then texturing and washing operations are performed. The texturing points of the battery cell raw materials are then detected. The principle of light limiting is used to reduce light reflection, improve Isc, and increase the area of ​​the PN junction. S2. Then, the cell material is diffused: the qualified cells after texturing are diffused and then the cells are sampled and inspected. Diffusion is used to make PN junctions. Different doping processes are used. Through diffusion, the same silicon wafer can simultaneously have P-type semiconductors and N-type semiconductors. A space charge region is formed at their interface, which is called a PN junction. The PN junction has unidirectional conductivity. S3. Remove PSG from the solar cells: Wash the surface of the solar cells with hydrofluoric acid solution to remove PSG. After the diffusion process of solar cells, a layer of PSG, which is phosphosilicate glass, will be formed on the surface of the silicon wafer. It needs to be removed by washing with hydrofluoric acid solution to avoid short circuit of PN junction and reduction of parallel resistance. S4. Oxidation treatment of solar cells: After the PSG is washed away, the solar cells are fed into the equipment by a robotic arm for oxidation treatment. That is, oxygen atoms combine with unsaturated silicon atoms on the silicon surface to form a SiO2 film, thereby reducing the dangling bond density on the silicon wafer surface, effectively controlling interface traps and fixing charges, and achieving the purpose of passivating the surface of solar cells. S5. Back film treatment of solar cells: The solar cells are transported into the equipment for back film treatment to prepare a back passivation dielectric layer. This layer protects the passivation layer from the penetration of water vapor and metal ions, and provides waterproofing, insulation and aging resistance. S6. Apply positive coating treatment to the solar cells: Apply positive coating treatment to the solar cells in the same way as the back coating treatment to achieve surface passivation effect and optical anti-reflection performance; S7. Laser processing of solar cells: Laser grooving of solar cells is performed by using a laser to drill holes or grooves on the back of the silicon wafer, exposing part of the Al2O3 and SiNx thin film layers to expose the silicon substrate. The back electric field contacts the silicon substrate through the holes or grooves on the thin film. S8. Screen printing the battery: Print the back electrode, back electric field and positive electrode on the battery cell, and the back electrode printing provides the physical positive electrode for the final battery cell. Back electrode printing involves redoping to form a P+ layer, reducing carrier recombination and increasing the on-state voltage; positive electrode printing collects photocurrent and provides the physical negative electrode of the solar cell.

2. The manufacturing process of a battery cell according to claim 1, characterized in that: The texturing process in S1 utilizes the anisotropic etching properties of silicon to etch a pyramid-like or honeycomb-like structure onto the silicon wafer surface using HF & HNO3 or KOH (NaOH). The process of making the pile requires pre-washing, first water wash, first pile making, second pile making, second water wash, alkaline wash, third water wash, acid wash, fourth water wash and pre-washing, and finally drying.

3. The manufacturing process of a battery cell according to claim 1, characterized in that: The diffusion in S2 uses a phosphorus oxychloride liquid source diffusion method to form an N-type layer on the silicon wafer surface, and during the diffusion step, the front and back sides are distinguished.

4. The manufacturing process of a battery cell according to claim 1, characterized in that: In step S3, the removal of PSG utilizes the reaction between HF and the P-Si glass layer on the silicon wafer surface, causing them to complex and peel off, thereby achieving a cleaning effect and realizing single-sided etching of the silicon wafer.

5. The manufacturing process of a battery cell according to claim 1, characterized in that: Before oxidation in step S4, the battery cells are first subjected to alkaline polishing, which includes pre-cleaning, first water washing, alkaline polishing, second water washing, alkaline washing, third water washing, acid washing, fourth water washing and pre-rinsing, and finally drying.

6. The manufacturing process of a battery cell according to claim 1, characterized in that: The backsheet reaction formula in S5 is as follows: TMA + N2O (laughing gas) → AL2O3; PECVD deposition of ALOx+SiNx thin films; The positive film in S6 is a SiNx antireflection film deposited by PECVD. The PECVD system is a series of generators that utilize a parallel plate coating boat and a high-frequency plasma exciter. Under low pressure and high temperature, the plasma generator stimulates silane and nitrogen to form a plasma state and react on the surface of the silicon wafer in the middle of the parallel plate coating boat. These gases are plasmaized and stored on the silicon wafer to produce silicon nitride.

7. A tool for measuring contact points during the fabrication process of a battery cell, characterized in that: It includes a transparent acrylic upper plate (1) and a transparent acrylic lower plate (2). A first magnet (101) is embedded in each of the four corners of the transparent acrylic upper plate (1). A second magnet (206) is embedded in each of the four corners of the upper end of the transparent acrylic lower plate (2). A placement groove (201) is opened on one side of the transparent acrylic lower plate (2). Several sets of contact point measuring tools are prepared, each corresponding to the product processed in each step of claim 1. The lower transparent acrylic plate (2) has chamfered edges (203) at the four corners of the placement groove (201), through holes (202) at the four corners of the placement groove (201), and a snap-pull elliptical groove (204) at the front end of the placement groove (201). A snap-pull hole (205) is provided on the snap-pull elliptical groove (204). The upper surface of the upper transparent acrylic plate (1) will show the key dimensions and shapes of the contact points in the process in a mapping form on the acrylic plate using spraying technology. By placing the battery cell between the lower transparent acrylic plate (2) and the upper transparent acrylic plate (1), the defect location can be clearly compared with the contact point of a certain process machine, directly hitting the key point.

8. The contact point measuring tool for the manufacturing process of a battery cell according to claim 7, characterized in that: A first limiting ring (102) and a second limiting ring (207) are respectively attached to the four corners of the transparent acrylic upper plate (1) and the transparent acrylic lower plate (2). The first limiting ring (102) is located above the first magnet (101), and the second limiting ring (207) is located above the second magnet (206).

9. The contact point measuring tool for the manufacturing process of a battery cell according to claim 7, characterized in that: The preparation process of the contact point measurement tool is as follows: S01. Material size selection: 1:1 specification, original size A3, 420*297; S02. The white parts of the lines should be transparent, and the lines should be clear. S03. Two 2mm acrylic sheets are required. One of them should have UV protection applied to the front and back surfaces after the printing lines are completed to increase wear resistance. S04, another silicon wafer requires a 183x183mm groove with a depth of 160um, and a smooth surface with good transparency; S05. The four corners of the acrylic sheet are rounded with R5, and the machined surface is deburred to prevent scratches to operators. S06: The four corners of the front and rear acrylic panels are equipped with magnetic closure for easy storage and organization. S07. Title optimization: Add company logo; S08. The contact point measuring tool will be fixed on the machine or wall. Each set needs to be equipped with 4 table plate fixing clips or glass support clips to facilitate fixing the tool and easy to pick up.

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