Screen printing process, screen printing equipment, solar cells and heterojunction cells

Abstract

This invention relates to a screen printing process, a screen printing apparatus, a battery cell, and a heterojunction battery. The process involves using a drying component to dry the substrate to meet a preset drying requirement, followed by cooling with a cooling element to cool the substrate and ensure the electrode curing rate meets a preset curing requirement. This achieves both high drying rate and high battery efficiency while preventing electrode scratches, thus improving the yield and quality of the battery cell.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a screen printing process, screen printing apparatus, battery cells, and heterojunction batteries. Background Technology

[0002] In the production of heterojunction solar cells, the electrodes are fabricated using screen printing. Specifically, the substrate, after PVD (Physical Vapor Deposition) processing, is sequentially printed four times using a screen printing assembly: a front fine electrode, a front main electrode, a back fine electrode, and a back main electrode, to obtain the solar cell. After each printing step, the substrate is transported by conveyor belt to a drying assembly for drying. After drying, it is transported back to the screen printing assembly for the next printing step (for example, after fabricating the front fine electrode using the screen printing assembly, the substrate is transported to the drying assembly for drying, and then transported back to the screen printing assembly for fabricating the front main electrode). This process is repeated to complete the electrode fabrication. During the transport process, the electrodes are easily scratched, affecting the quality of the solar cell. Summary of the Invention

[0003] Therefore, it is necessary to provide a screen printing process, screen printing device, battery cell and heterojunction battery to address the problem that electrodes are easily scratched during transportation.

[0004] The technical solution is as follows:

[0005] On the one hand, a screen printing process is provided, including the following steps:

[0006] The substrate after one electrode printing is dried to ensure that the drying rate of the substrate meets the preset drying requirements.

[0007] After drying, the substrate is transferred to the next electrode printing process. During the transfer, the substrate is cooled to ensure that the curing rate of the electrode meets the preset curing requirements to avoid scratching.

[0008] The technical solution will be further explained below:

[0009] In one embodiment, the step of drying the substrate after one electrode printing to make the drying rate of the substrate meet the preset drying requirements includes: drying the substrate after one electrode printing at a temperature of 140°C to 180°C for 9 min to 12 min.

[0010] In one embodiment, the step of drying the substrate after one electrode printing includes drying the substrate after one electrode printing at a temperature of 150°C to 160°C for 9 min to 12 min.

[0011] In one embodiment, the step of cooling the substrate during the transfer process includes: reducing the temperature of the substrate transferred from the drying chamber to below 70°C before it is transferred to the first conveyor belt, so that the curing rate of the electrode meets the preset curing requirements to avoid scratching.

[0012] In one embodiment, the step of reducing the temperature of the substrate transferred from the drying chamber to below 70°C before it is transferred to the first conveyor belt during the transfer process includes: using a carrier to support the substrate and moving it from the drying chamber toward the first conveyor belt; when the carrier is moved out of the drying chamber, using a cooling element to blow air onto the substrate on the carrier to cool it until the carrier places the substrate in front of the first conveyor belt so that the temperature of the substrate is reduced to below 70°C.

[0013] In one embodiment, when the carrier is removed from the drying chamber, the substrate on the carrier is cooled by blowing air through a cooling element until the temperature of the substrate is reduced to below 70°C before the carrier places the substrate in front of the first conveyor belt.

[0014] Temperature signals are obtained by detecting the temperature of the electrodes;

[0015] By combining the temperature signal, the moving distance and speed of the carrier from the drying chamber to the substrate being placed on the first conveyor belt, the blowing power of the cooling element is adjusted so that the temperature of the electrode before the substrate is placed on the first conveyor belt is reduced to below 70°C.

[0016] In one embodiment, in the step of drying the substrate after one electrode printing to achieve a drying rate that meets a preset drying requirement, the drying rate is 4.5% to 6%.

[0017] On the other hand, a screen printing apparatus is provided, comprising:

[0018] A screen printing assembly for fabricating electrodes on a substrate;

[0019] A drying assembly is used to dry a substrate after one electrode printing process, so that the drying rate of the substrate meets the preset drying requirements.

[0020] A first conveyor belt is used to transfer the dried substrate to the screen printing assembly for the next electrode printing.

[0021] A carrier for transferring a substrate within the drying assembly to the first conveyor belt; and

[0022] A cooling element is provided for cooling the substrate transferred from the drying assembly to the first conveyor belt so that the curing rate of the electrode meets the preset curing requirements and is prevented from being scratched.

[0023] On the other hand, a battery cell is provided, which is manufactured using the aforementioned screen printing process.

[0024] On the other hand, a heterojunction battery is provided, which is manufactured using the aforementioned screen printing process.

[0025] The screen printing process, screen printing apparatus, battery cell, and heterojunction battery described in the above embodiments have at least the following advantages: 1. After the substrate is dried by the drying component to meet the preset drying requirements, the substrate is then cooled by the cooling element to meet the preset curing requirements. This achieves both high drying rate and high battery efficiency while preventing the electrodes from being scratched, thus improving the yield and quality of the battery cells; 2. The blowing power of the cooling element is flexibly adjusted by combining the temperature signal, moving distance, and moving speed to ensure that the temperature of the electrodes can be reduced to below 70°C before the substrate is placed on the first conveyor belt, so that the electrodes will not be scratched when they come into contact with the first conveyor belt. Attached Figure Description

[0026] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A flowchart of a screen printing process according to one embodiment;

[0029] Figure 2 A flowchart of a screen printing process according to another embodiment;

[0030] Figure 3 To adopt Figure 1 The yield and defect rate after the screen printing process. Detailed Implementation

[0031] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0032] Traditionally, after the silicon wafer completes the PVD process, a substrate is obtained. During the screen printing process, the substrate is first screen printed with fine electrodes on the front or back side using a screen printing assembly. Then, the substrate with the front or back fine electrodes printed is transferred to a drying assembly for drying. After drying, the substrate is transferred to a screen printing assembly for printing the main electrodes on the front or back side. This process is repeated. Finally, the substrate is transferred out of the drying assembly, completing the fabrication of the entire electrode assembly (back fine electrode, back main electrode, front fine electrode, and front main electrode). During the process of transferring the substrate from the drying assembly to the screen printing assembly, the electrodes will come into contact with the conveyor belt. Under the action of friction, the electrodes are easily scratched, which will affect the quality of the solar cells.

[0033] In one embodiment, a screen printing apparatus is provided that can perform a screen printing process on a substrate and ensure that the electrodes are not scratched, thus guaranteeing the quality of the solar cells.

[0034] Specifically, the screen printing apparatus includes a screen printing assembly, a drying assembly, a first conveyor belt, a carrier, and a cooling element.

[0035] Among them, the screen printing component can be an existing screen printing machine or other device capable of screen printing on a substrate to create electrodes.

[0036] The drying assembly can be in the form of a drying oven or a drying box. The drying assembly is used to dry the substrate after one electrode printing cycle, ensuring the substrate's drying rate meets preset drying requirements.

[0037] One method is to use heating wires to dry the substrate.

[0038] Specifically, the drying assembly is equipped with a drying chamber, which is used to transfer the substrate after the first electrode printing to the drying chamber for drying treatment, so that the drying rate of the substrate meets the preset drying requirements, thereby ensuring the battery efficiency of the produced solar cells and meeting the requirements for high performance.

[0039] The substrate, which has undergone one electrode printing process using a screen printing assembly, is transferred to the drying chamber for drying. This can be done using a conveyor belt, a conveyor chain, or a robotic arm for gripping and transferring. The process simply involves transferring the substrate from the screen printing assembly to the drying chamber for drying.

[0040] The first conveyor belt is located between the drying assembly and the screen printing assembly. The first conveyor belt can be used to transfer the substrate after drying to the screen printing assembly for the next electrode printing.

[0041] Specifically, the substrate, after one electrode printing cycle, is transferred to a carrier located within the drying chamber. The carrier supports the substrate, and as it moves within the drying chamber, it simultaneously dries the substrate. Furthermore, the carrier can move the substrate out of the drying chamber and transfer it to a first conveyor belt, which then transfers the substrate to a screen printing assembly for the next electrode printing cycle.

[0042] The carrier can be in the form of a plate, a pallet, or a frame, as long as it can support and transport the substrate.

[0043] Specifically, a cooling element is used to cool the substrate during its transfer from the drying assembly to the first conveyor belt. This ensures that the electrode curing rate meets the preset curing requirements, thereby preventing scratches caused by friction during transport on the first conveyor belt and guaranteeing the quality of the solar cells. Furthermore, after the drying assembly dries the substrate to meet the preset drying requirements, the cooling element further cools the substrate to ensure the electrode curing rate meets the preset curing requirements. This achieves both high drying rate and high battery efficiency while preventing electrode scratches, improving the yield and quality of the solar cells.

[0044] The preset curing requirement means that the electrode hardness is sufficient to prevent it from being scratched during the conveying process in contact with the first conveyor belt.

[0045] The cooling element can be a fan knife, an air outlet, or other element that can blow air onto the substrate for cooling.

[0046] Specifically, the drying chamber has an inlet and an outlet. The substrate that has completed one electrode printing enters the drying chamber through the inlet and is placed on a carrier. The carrier carries the substrate and moves it toward the outlet in the drying chamber while simultaneously drying the substrate, so that the drying rate of the substrate meets the preset drying requirements and improves the battery efficiency of the produced solar cell. When the carrier moves the substrate out of the drying chamber through the outlet, the cooling element cools the substrate on the carrier, so that the curing rate of the electrode meets the preset curing requirements, thereby making the electrode harder. When the carrier places the substrate on the first conveyor belt and the electrode comes into contact with the first conveyor belt, even if it is subjected to friction from the first conveyor belt during operation, it will not scratch the electrode, thus ensuring the quality of the solar cell.

[0047] In order to ensure that the substrates on the carrier can be effectively dried and cooled, the moving speed of the carrier can be flexibly designed or adjusted according to the actual drying and cooling requirements. For example, it can be 0.005m / s to 0.008m / s. This not only ensures transfer efficiency and high productivity, but also ensures that the substrates can be effectively dried and cooled.

[0048] In one embodiment, a screen printing process is also provided, which can fabricate electrodes on a substrate after the PVD process is completed, ensuring that the electrodes are not scratched and guaranteeing the quality of the solar cells.

[0049] like Figure 1 As shown, the screen printing process includes the following steps:

[0050] S100. The substrate after one electrode printing is dried to ensure that the drying rate of the substrate meets the preset drying requirements.

[0051] Specifically, after the substrate is printed with electrodes once using a screen printing assembly, the substrate is transferred to the drying chamber of the drying assembly for heating and drying until the substrate's drying rate meets the preset drying requirements, thereby ensuring the battery efficiency of the manufactured solar cells and meeting the requirements for high-performance use.

[0052] More specifically, the substrate after one electrode printing is completed is transferred to a carrier located in the drying chamber. The carrier supports the substrate, and the substrate is dried simultaneously as the carrier moves within the drying chamber.

[0053] It is understandable that the drying rate refers to the percentage of the weight of the substrate after drying to the weight of the substrate before drying.

[0054] like Figure 2As shown, more specifically, step S100 includes: S110, drying the substrate after one electrode printing at a temperature of 140°C to 180°C for 9 to 12 minutes. Thus, the substrate after one electrode printing is placed on a carrier and continuously dried in a drying chamber at a temperature of 140°C to 180°C for 9 to 12 minutes, ensuring that the substrate's drying rate meets the preset drying requirements and improving the battery efficiency of the manufactured solar cell.

[0055] In one embodiment, the substrate after one electrode printing is dried at 140°C for 9 minutes, resulting in a substrate drying rate of 5.97%.

[0056] In one embodiment, the substrate after one electrode printing is dried at 140°C for 12 minutes, resulting in a substrate drying rate of 5.32%.

[0057] In one embodiment, the substrate after one electrode printing is dried at 180°C for 9 minutes, resulting in a substrate drying rate of 5.67%.

[0058] In one embodiment, the substrate after one electrode printing is dried at 180°C for 12 minutes, resulting in a substrate drying rate of 4.95%.

[0059] Preferably, the substrate after the first electrode printing is dried at a temperature of 150℃ to 160℃ for 9 to 12 minutes. Thus, the substrate after the first electrode printing is placed on a carrier and dried continuously in a drying chamber at 150℃ to 160℃ for 9 to 12 minutes, with the temperature fluctuation range controlled to be less than 5℃. This ensures that the substrate drying rate better meets the preset drying requirements, and more effectively improves the battery efficiency of the manufactured solar cells.

[0060] In one embodiment, the substrate after one electrode printing is dried at 150°C for 9 minutes, resulting in a substrate drying rate of 5.59%.

[0061] In one embodiment, the substrate after one electrode printing is dried at 150°C for 12 minutes, resulting in a substrate drying rate of 5.18%.

[0062] In one embodiment, the substrate after one electrode printing is dried at 180°C for 9 minutes, resulting in a substrate drying rate of 5.47%.

[0063] In one embodiment, the substrate after one electrode printing is dried at 180°C for 12 minutes, resulting in a substrate drying rate of 5.04%.

[0064] Preferably, in step S100, after the substrate is dried following the completion of one electrode printing, the drying rate of the substrate is 4.5% to 6%, which can meet the preset drying requirements, achieve a high drying rate, ensure that the obtained battery cell has high battery efficiency, and meet the needs of heterojunction battery use.

[0065] It is understandable that the drying rate of the substrate can be 4.5%, 4.75%, 5%, 5.25%, 5.5%, 5.75%, or 6%. It can be flexibly designed or adjusted according to the actual drying conditions or drying requirements to ensure that the produced solar cells have high cell efficiency and meet the needs of heterojunction solar cells.

[0066] S200: The substrate after drying is transferred to the next electrode printing process. During the transfer, the substrate is cooled to ensure that the electrode curing rate meets the preset curing requirements to avoid scratches.

[0067] Specifically, cooling elements are used to cool the substrate during its transfer from the drying chamber of the drying assembly to the first conveyor belt. This ensures that the electrode curing rate meets the preset curing requirements, thereby preventing the substrate from being scratched by friction during transport on the first conveyor belt and guaranteeing the quality of the solar cells. Furthermore, after the drying assembly dries the substrate to meet the preset drying requirements, the cooling elements are then used to further cool the substrate, ensuring that the electrode curing rate meets the preset curing requirements. This achieves both high drying rate and high battery efficiency while preventing electrode scratches, thus improving the yield and quality of the solar cells.

[0068] like Figure 2 As shown, in step S200, the following steps are included: S210, the temperature of the substrate transferred from the drying chamber to the first conveyor belt is reduced to below 70°C, so that the curing rate of the electrode meets the preset curing requirements to avoid scratching. In this way, the temperature of the dried electrode is reduced to below 70°C before contacting the first conveyor belt, thereby ensuring that the curing rate of the electrode meets the preset requirements. This results in a harder electrode, preventing scratches even when it comes into contact with the first conveyor belt and experiences friction, thus guaranteeing product quality.

[0069] Specifically, step S210 includes S211, where a carrier supports the substrate and moves it from inside the drying chamber toward the first conveyor belt. When the carrier moves out of the drying chamber, a cooling element blows air onto the substrate on the carrier to cool it until the carrier places the substrate in front of the first conveyor belt, causing the temperature of the substrate to drop below 70°C.

[0070] More specifically, the drying chamber has an inlet and an outlet. The substrate that has completed one electrode printing enters the drying chamber through the inlet and is placed on a carrier. The carrier carries the substrate and moves it towards the outlet in the drying chamber while simultaneously drying the substrate, so that the drying rate of the substrate meets the preset drying requirements and improves the battery efficiency of the produced solar cell. When the carrier moves the substrate out of the drying chamber from the outlet and towards the first conveyor belt, the cooling element blows air to cool the substrate on the carrier, thereby cooling the electrode to below 70°C. The curing rate of the electrode meets the preset curing requirements and the hardness of the electrode is increased. When the carrier places the substrate on the first conveyor belt and the electrode comes into contact with the first conveyor belt, even if it is subjected to friction from the first conveyor belt during operation, it will not scratch the electrode, ensuring the quality of the solar cell.

[0071] Meanwhile, to ensure that the curing rate of the electrode accurately meets the preset curing requirements, step S211 specifically includes: detecting the temperature of the electrode to obtain a temperature signal; and adjusting the blowing power of the cooling element based on the temperature signal, the moving distance and speed of the carrier from the drying chamber to the substrate being placed on the first conveyor belt, so that the temperature of the electrode before the substrate is placed on the first conveyor belt is reduced to below 70°C. Thus, when the carrier carrying the dried substrate moves towards the first conveyor belt, the temperature of the electrode is detected using temperature sensing elements such as temperature probes to obtain a temperature signal, thereby accurately grasping the real-time temperature of the electrode and accurately cooling it to reduce its temperature to below 70°C. Considering that the moving distance and speed of the carrier carrying the substrate from the drying assembly to the first conveyor belt will affect the cooling effect of the electrode, the blowing power of the cooling element is flexibly adjusted based on the temperature signal, moving distance, and moving speed, effectively ensuring that the temperature of the electrode before the substrate is placed on the first conveyor belt is reduced to below 70°C, preventing the electrode from being scratched during contact and transfer with the first conveyor belt. Furthermore, by using the temperature signal from the temperature detection element to adjust the air blowing power of the cooling element, the cooling process of the substrate can be transformed into a closed-loop control, making the cooling process more intelligent and accurate.

[0072] More specifically, when the distance the carrier-mounted substrate travels from the drying assembly to the first conveyor belt is long, and the carrier's movement speed is slow, the blowing power of the cooling element can be appropriately reduced. It is sufficient to ensure that the temperature detection element detects that the electrode temperature has dropped below 70°C before the substrate is placed on the first conveyor belt, thus saving energy. When the distance the carrier-mounted substrate travels from the drying assembly to the first conveyor belt is short, and the carrier's movement speed is fast, the blowing power of the cooling element can be appropriately increased to ensure that the cooling element can effectively cool the electrode, so that the temperature detection element detects that the electrode temperature has dropped below 70°C before the substrate is placed on the first conveyor belt.

[0073] like Figure 3 As shown, in actual production, the screen printing process described in the above embodiment can reduce the percentage of defects caused by scratched electrodes from 25% to nearly 0%, and increase the overall yield of the solar cells from 65% to 94%.

[0074] The screen printing process described in the above embodiments has at least the following advantages: 1. After the substrate is dried by the drying component to meet the preset drying requirements, the substrate is then cooled by the cooling element to meet the preset curing requirements. This achieves both high drying rate and high battery efficiency while also preventing the electrodes from being scratched, thus improving the yield and quality of the battery cells; 2. The blowing power of the cooling element is flexibly adjusted by combining the temperature signal, moving distance, and moving speed to ensure that the temperature of the electrodes can be reduced to below 70°C before the substrate is placed on the first conveyor belt, so that the electrodes will not be scratched when they come into contact with the first conveyor belt.

[0075] In one embodiment, a battery cell is also provided, which is manufactured using the screen printing process of any of the above embodiments.

[0076] In the battery cell of the above embodiment, during the manufacturing process, the substrate is dried by a drying component to ensure that the drying rate of the substrate meets the preset drying requirements. Then, the substrate is cooled by a cooling element to ensure that the curing rate of the electrode meets the preset curing requirements. Under the premise of achieving high drying rate and high battery efficiency, the electrode can also be prevented from being scratched, thereby improving the yield and quality of the battery cell.

[0077] In one embodiment, a heterojunction solar cell is also provided, which is fabricated using the screen printing process described in any of the above embodiments.

[0078] In the heterojunction battery of the above embodiment, during the preparation process, the substrate is dried by a drying component to ensure that the drying rate of the substrate meets the preset drying requirements. Then, the substrate is cooled by a cooling element to ensure that the curing rate of the electrode meets the preset curing requirements. Under the premise of achieving high drying rate and high battery efficiency, the electrode can also be prevented from being scratched, thereby improving the yield and quality of the battery cells.

[0079] It should be noted that "a certain body" or "a certain part" can be a portion of the corresponding "component," meaning that "a certain body" or "a certain part" is integrally formed and manufactured with the "other parts of the component"; or it can be an independent component that can be separated from the "other parts of the component," meaning that "a certain body" or "a certain part" can be manufactured independently and then combined with the "other parts of the component" to form a whole. The expression of "a certain body" or "a certain part" in this application is only one embodiment for ease of reading, and is not intended to limit the scope of protection of this application. Any technical solution that includes the above features and has the same function should be understood as an equivalent technical solution of this application.

[0080] It should be noted that the components included in the terms "unit," "component," "mechanism," and "device" of this application can be flexibly combined, enabling modular production according to actual needs and facilitating modular assembly. The division of the above-mentioned components in this application is merely one embodiment for ease of reading and is not intended to limit the scope of protection of this application. Any solution that includes the above-mentioned components and has the same function should be understood as an equivalent technical solution of this application.

[0081] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. The term "and / or" used in this invention includes any and all combinations of one or more of the related listed items.

[0082] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0083] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0084] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0085] It should be noted that when a component is referred to as "fixed to," "set on," "fixed to," or "mounted on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component. Furthermore, when a component is considered to be "fixed transmission connection" to another component, the two can be fixed in a detachable or non-detachable manner, as long as power transmission can be achieved, such as sleeve, snap-fit, integral molding, welding, etc., which can be achieved in the prior art and will not be elaborated here. When a component is perpendicular or approximately perpendicular to another component, it means that the two are ideally perpendicular, but due to the influence of manufacturing and assembly, there may be a certain degree of perpendicularity error. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation. The term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0086] It should also be understood that, in interpreting the connection or positional relationships of components, although not explicitly described, connection and positional relationships are interpreted to include a range of error, which should be within the acceptable deviation range of a specific value as determined by a person skilled in the art. For example, "approximately," "about," or "substantially" can mean within one or more standard deviations, without limitation herein.

[0087] 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.

[0088] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A screen printing process, characterized in that, Includes the following steps: The substrate after one electrode printing is dried to ensure that the drying rate of the substrate meets the preset drying requirements. After the substrate has been dried, it is transferred to the next electrode printing process. During the transfer, the substrate is cooled to ensure that the curing rate of the electrode meets the preset curing requirements to avoid scratching. The step of cooling the substrate during transport includes: The temperature of the substrate transferred from the drying chamber is reduced to below 70°C before it is transferred to the first conveyor belt, so that the curing rate of the electrode meets the preset curing requirements to avoid scratching.

2. The screen printing process according to claim 1, characterized in that, The step of drying the substrate after one electrode printing process to ensure that the substrate's drying rate meets a preset drying requirement includes: The substrate after one electrode printing is dried at a temperature of 140℃ to 180℃ for 9 min to 12 min.

3. The screen printing process according to claim 1, characterized in that, The step of drying the substrate after one electrode printing process includes: The substrate after one electrode printing is dried at a temperature of 150℃~160℃ for 9min~12min.

4. The screen printing process according to any one of claims 1 to 3, characterized in that, During the transfer process, the step of reducing the temperature of the substrate transferred from the drying chamber to below 70°C before it is transferred to the first conveyor belt includes: The substrate is carried by a carrier and moved from the drying chamber toward the first conveyor belt. When the carrier moves out of the drying chamber, the substrate on the carrier is cooled by blowing air through a cooling element until the carrier places the substrate in front of the first conveyor belt and the temperature of the substrate drops below 70°C.

5. The screen printing process according to claim 4, characterized in that, When the carrier is removed from the drying chamber, the substrate on the carrier is cooled by blowing air through a cooling element until the temperature of the substrate is reduced to below 70°C before the carrier places the substrate in front of the first conveyor belt. This process includes: Temperature signals are obtained by detecting the temperature of the electrodes; By combining the temperature signal, the moving distance and speed of the carrier from the drying chamber to the substrate being placed on the first conveyor belt, the blowing power of the cooling element is adjusted so that the temperature of the electrode before the substrate is placed on the first conveyor belt is reduced to below 70°C.

6. The screen printing process according to claim 5, characterized in that, In the step of adjusting the blowing power of the cooling element based on the temperature signal, the moving distance and speed of the carrier from the drying chamber to the substrate being placed on the first conveyor belt, so that the temperature of the electrode before the substrate is placed on the first conveyor belt is reduced to below 70°C, when the distance the carrier carrying the substrate moves from the drying assembly to the first conveyor belt is long and the moving speed of the carrier is slow, the blowing power of the cooling element is reduced; when the distance the carrier carrying the substrate moves from the drying assembly to the first conveyor belt is short and the moving speed of the carrier is fast, the blowing power of the cooling element is increased.

7. The screen printing process according to any one of claims 1 to 3, characterized in that, In the step of drying the substrate after one electrode printing to ensure that the drying rate of the substrate meets the preset drying requirements, the drying rate is 4.5% to 6%.

8. A screen printing apparatus, characterized in that, include: A screen printing assembly for fabricating electrodes on a substrate; A drying assembly is used to dry a substrate after one electrode printing process, so that the drying rate of the substrate meets the preset drying requirements. A first conveyor belt is used to transfer the dried substrate to the screen printing assembly for the next electrode printing. A carrier for transferring a substrate within the drying assembly to the first conveyor belt; The equipment includes a cooling element for cooling the substrate transferred from the drying assembly to the first conveyor belt so that the curing rate of the electrodes meets the preset curing requirements and is prevented from being scratched.

9. A battery cell, characterized in that, It is produced by screen printing process as described in any one of claims 1 to 7.

10. A heterojunction battery, characterized in that, It is produced by screen printing process as described in any one of claims 1 to 7.

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