Method of assembling photovoltaic cell stack

Abstract

The application discloses a photovoltaic cell laminated assembly preparation method, which comprises the following steps: laminating a pre-windowed back adhesive film on a back glass, wherein the back glass is provided with a prefabricated circuit, the prefabricated circuit is provided with a conductive pad, and the windowing position of the back adhesive film is matched with the conductive pad; laminating a plurality of cell pieces provided with conductive pads on the back adhesive film, wherein the conductive pads are matched with the positions of the conductive pads; and performing local alloying welding on the laminated back glass and cell pieces to obtain a first semi-finished product. The back glass provided with the prefabricated circuit is used to realize the interconnection of the plurality of cell pieces, the solder strip can be cancelled, the solder strip welding process can be cancelled, the cell piece warping or fragmentation caused by the solder strip welding can be avoided, the manufacturing process can be simplified, and the processing efficiency is improved; the local alloying welding after the laminated assembly of the back glass, the back adhesive film and the cell pieces can avoid the heat stress concentration, thereby avoiding the cell piece warping or fragmentation.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a method for preparing a laminated assembly of photovoltaic cells. Background Art

[0002] In photovoltaic cell technology, back contact (BC) technology removes the grid lines from the front of the cell and places electrodes only on the back, reducing front-side obstruction and improving conversion efficiency. However, back contact cell modules are encapsulated using a ribbon welding process. When the back electrode of the cell is welded to the ribbon, the entire cell is heated. The localized high temperature (e.g., 200-300°C) at the ribbon connection point can cause thermal stress concentration in the cell, making it prone to warping after cooling and, in severe cases, even fragmentation. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for preparing a photovoltaic cell stack assembly, which interconnects the cells through stack assembly, eliminates solder ribbons, and avoids warping or fragmentation of the cells caused by solder ribbons.

[0004] An embodiment of the present invention provides a method for preparing a photovoltaic cell stack assembly, comprising:

[0005] The back adhesive film with pre-opened windows is stacked on the back glass, wherein the back glass is provided with a prefabricated circuit, the prefabricated circuit is provided with a conductive pad, and the window position of the back adhesive film is adapted to the conductive pad;

[0006] Stacking a plurality of battery cells provided with conductive solder joints on the back film, wherein the conductive solder joints are adapted to the positions of the conductive pads;

[0007] The stacked back glass and the battery cell are locally alloyed and welded to obtain a first semi-finished product.

[0008] According to some embodiments of the present invention, the step of stacking a plurality of battery cells provided with conductive solder joints on the backside adhesive film further includes:

[0009] The battery cell is pre-pressed with a preset pressure so that the distance between the conductive pad and the conductive solder point is less than or equal to a preset threshold.

[0010] According to some embodiments of the present invention, pre-pressing the battery cell with a preset pressure so that the distance between the conductive pad and the conductive solder joint is less than or equal to a preset threshold value includes:

[0011] The battery cell is pre-pressed with a pressure of 1-2N so that the surface distance between the conductive pad and the conductive solder point is less than or equal to 50 μm.

[0012] According to some embodiments of the present application, the local alloying welding of the back glass and the cell piece after stacking includes:

[0013] Configuring a heating parameter of the pulse hot-press welding device;

[0014] Controlling the pulse hot-press welding device to locally heat the conductive pad and the conductive spot based on visual guidance to perform alloying welding.

[0015] According to some embodiments of the present application, the heating parameter includes a temperature of 220-240℃, a pressure of 3-5N, and a heating time of 8-10s.

[0016] According to some embodiments of the present application, the local alloying welding of the back glass and the cell piece after stacking obtains a first semi-finished product, and then further includes:

[0017] Stacking a front adhesive film and a front glass on the cell piece surface of the first semi-finished product in sequence to obtain a second semi-finished product.

[0018] According to some embodiments of the present application, the stacking of the front adhesive film and the front glass on the cell piece surface of the first semi-finished product to obtain the second semi-finished product further includes:

[0019] Filling an elastic buffer pad or coating a buffer adhesive between the back glass and the cell piece.

[0020] According to some embodiments of the present application, the stacking of the front adhesive film and the front glass on the cell piece surface of the first semi-finished product to obtain the second semi-finished product further includes:

[0021] Sending the second semi-finished product into a laminating device;

[0022] Controlling the laminating device to press the second semi-finished product based on a segmented pressure loading mode to obtain a third semi-finished product.

[0023] According to some embodiments of the present application, the controlling of the laminating device to press the second semi-finished product based on the segmented pressure loading mode includes:

[0024] Controlling the laminating device to enter a vacuum state and maintain for a first preset time length;

[0025] Controlling the laminating device to increase pressure in stages, wherein the pressure is increased to a first pressure value and maintained for a second preset time in the first stage, the pressure is increased to a second pressure value and maintained for a third preset time in the second stage, and the pressure is increased to a third pressure value and maintained for a fourth preset time in the third stage, wherein the second preset time, the third preset time, and the fourth preset time are shortened in sequence;

[0026] The laminating device is controlled to enter a pressure holding state and maintain the state for a fifth preset time, wherein the temperature of the pressure holding state is maintained at 140-160° C.

[0027] According to some embodiments of the present invention, controlling the lamination device to perform phased pressure boosting includes:

[0028] Controlling the first stage pressure value of the laminating device to increase from the vacuum pressure value to 0.3 MPa and maintain it for 5 minutes;

[0029] Control the second stage pressure value of the laminating device to increase to 0.6 MPa and maintain it for 3 minutes;

[0030] The third stage pressure value of the laminating device was controlled to increase to 0.8 MPa and maintained for 2 minutes.

[0031] The embodiments of the present invention have at least the following beneficial effects:

[0032] By using back glass with prefabricated circuits to interconnect multiple battery cells, the soldering ribbons and the soldering ribbon welding process can be eliminated, which can prevent the soldering ribbons from causing the battery cells to warp or break, and can also simplify the manufacturing process and improve processing efficiency. Local alloying welding is performed after the back glass, back film and battery cells are stacked and assembled to avoid thermal stress concentration, thereby preventing the battery cells from warping or breaking.

[0033] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0035] Figure 1 A flowchart of the steps of the photovoltaic cell stacking and assembly process according to an embodiment of the present invention;

[0036] Figure 2 Schematic diagram of the stacked structure of a photovoltaic cell according to an embodiment of the present invention;

[0037] Figure 3 Schematic diagram of a plan view of the back glass of a photovoltaic cell according to an embodiment of the present invention;

[0038] Figure 4 FIG. 1 is a schematic perspective view of a photovoltaic cell according to an embodiment of the present invention.

[0039] Reference numerals:

[0040] Front glass 100 , back glass 200 , interconnection strips 210 , conductive pads 211 , bus bars 220 , front adhesive film 300 , back adhesive film 400 , window openings 410 , battery cells 600 , and conductive solder joints 610 . DETAILED DESCRIPTION

[0041] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0042] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0043] In the description of the present invention, "several" means one or more, "multiple" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, and "above," "below," and "within" are understood to include the number itself. The use of terms such as "first" and "second" is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0044] In the description of the present invention, unless otherwise clearly defined, words such as “setting”, “installation” and “connection” should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above words in the present invention based on the specific content of the technical solution.

[0045] The traditional photovoltaic cell manufacturing process includes material preparation, cell welding, layout, lap welding, and lamination. The cell welding process involves using solder ribbon to weld multiple cells 600 arranged on the assembly line to achieve series connection between the cells 600. Layout involves neatly stacking the multiple series-connected cell groups 600 on the back glass 200 in a predetermined arrangement. Lapping involves welding busbars 220 to the solder ribbons of the multiple cell groups 600 stacked on the back glass 200 to interconnect the multiple cell groups 600. Lamination involves pressing the assembled back glass 200, back film 400, cell 600, front film 300, and front glass 100 together. During the cell welding process, when the back electrodes of the cell 600 are welded to the solder ribbon, localized high temperatures (e.g., 200-300°C) can cause thermal stress concentration in the cell 600, leading to warping and, in severe cases, fragmentation after cooling. In addition, there is a contact resistance at the welding interface between the welding ribbon and the electrode of the cell 600, which is usually ≥200mΩ, accounting for 30%~40% of the internal loss of the photovoltaic cell, resulting in low conversion efficiency of the photovoltaic cell. The tension of the welding ribbon during the welding process can easily cause microcracks in the cell 600, which will further increase the current transmission loss.

[0046] Please refer to Figure 1 This embodiment discloses a method for preparing a photovoltaic cell stack assembly, including steps S100 to S300. It should be noted that the numbering of the steps in this embodiment is only for ease of review and understanding, and does not limit the order in which the steps are executed. The following is a detailed description of the contents of each step:

[0047] S100, stacking the pre-windowed back film 400 on the back glass 200, the back glass 200 being provided with a prefabricated circuit, the prefabricated circuit being provided with a conductive pad 211, and the window position 410 of the back film 400 being adapted to the conductive pad 211;

[0048] For example, please refer to Figure 2 and Figure 3 In some application examples, the prefabricated circuit includes an interconnection bar 210, on which a conductive pad 211 is provided. The interconnection bar 210 is used to replace the traditional soldering ribbon and is prefabricated on the back glass 200. The back glass 200 can be made of conventional tempered glass, which has sufficient mechanical strength to protect the battery cell 600. In traditional processes, the back glass 200 is a flat and smooth glass structure. In this embodiment, a prefabricated circuit is provided on the back glass 200, and the prefabricated circuit can realize the interconnection between different battery cells 600; in other application examples, please refer to Figure 3The prefabricated circuit includes interconnecting bars 210 and bus bars 220, wherein the interconnecting bars 210 can be divided into N-type interconnecting bars and P-type interconnecting bars. The N-type interconnecting bars are used to connect the negative electrodes of the battery cells 600. The N-type interconnecting bars are provided with N-type conductive pads, such as Figure 3 The square pad shown on the left is a P-type interconnection bar used to connect the positive electrode of the battery cell 600. A P-type conductive pad is provided on the P-type interconnection bar. Figure 3 The circular pad is shown on the right. It should be noted that the shape of the conductive pad 211 shown in the figure is only for distinguishing the type and not the actual pad shape. The interconnection bars 210 of the same type are connected through the corresponding bus bars 220 to output the electrical energy through the bus bars 220. Prefabricating the interconnection bars 210 and bus bars 220 on the back glass 200 can eliminate the welding process of the soldering ribbon and the welding process of the bus bars 220 in the production process, which is conducive to simplifying the process and avoiding quality problems caused by welding.

[0049] Before stacking, the back film 400 undergoes a pre-windowing process to create a window position 410 on the back film 400. The position and size of the window position 410 are adapted to the position and size of the conductive pad 211, so as to avoid the conductive pad 211. The back film 400 can be made of EVA film, EPE film, or POE film. EVA film is a thermosetting and adhesive film. EVA is short for Polyethylene vinylacetate, a polyethylene-polyvinyl acetate copolymer. EPE stands for Expandable Polyethylene, a non-cross-linked closed-cell structure material made from low-density polyethylene (LDPE) through a physical foaming process. POE stands for Polyolefin Elastomer, a synthetic biodegradable polymer material.

[0050] S200, stacking multiple battery cells 600 provided with conductive solder joints 610 on the backside adhesive film 400, with the conductive solder joints 610 being aligned with the conductive pads 211;

[0051] For example, please refer to Figure 4In accordance with the process requirements, multiple battery cells 600 are arranged in a plane in a preset manner, and the arranged multiple battery cells 600 are stacked on the back film 400. For example, the back glass 200 is placed on a carrier and fixed, and the back film 400 is stacked on the back glass 200, and then multiple battery cells 600 are stacked on the back film 400 simultaneously. The stacking operation is usually completed by automated equipment with high alignment accuracy, which can meet the precise alignment of the back glass 200, the back film 400 and the battery cells 600. The position of the window position 410 of the back film 400 can adapt to the position of the conductive pad 211 of the back glass 200, and the position of the conductive solder joint 610 of the battery cell 600 can adapt to the position of the conductive pad 211 of the back glass 200.

[0052] In some application examples, the conductive pad 211 and the conductive solder joint 610 are concave-convex structures that are adapted to each other. For example, the conductive pad 211 is a circular structure, and the conductive solder joint 610 is a circular structure. The circular structure conductive solder joint 610 can be inserted into the middle of the circular structure conductive pad 211 to achieve a tight fit; or, in other application examples, the conductive pad 211 and the conductive solder joint 610 can both be circular structures, and the surfaces of the two are suitable for mutual connection.

[0053] S300 , performing local alloying welding on the stacked back glass 200 and the battery cell 600 to obtain a first semi-finished product.

[0054] For example, conventional cell welding involves heating the entire cell 600 using an infrared heating process, which then heats the solder ribbon on the cell 600, thereby connecting it to the busbars of the cell 600. This can easily lead to uneven stress, which can cause the cell 600 to warp after welding. In this embodiment, the back glass 200 and cell 600 are connected via mutually adapted conductive pads 211 and conductive solder joints 610. By performing local alloying welding on the stacked back glass 200 and cell 600, heat is radiated to the conductive solder joints 610 of the cell 600, causing the conductive pads 211 to melt and connect to the conductive solder joints 610. This eliminates the need for overall heating and welding of the cell 600, significantly reducing stress on the cell 600. Because the interconnection between the cells 600 is achieved via the interconnecting strips 210, eliminating the solder ribbon, ultra-low stress can be achieved, local stress concentration can be avoided, and warping or fragmentation of the cell 600 after cooling can be prevented, thereby ensuring the reliability of the cell 600. The cell 600 of this embodiment is an XBC cell. The metal contacts (such as conductive pads 610) of the cell 600 are all located on the same surface to facilitate connection with the interconnection strips 210. XBC cell technology is a back-contact solar cell technology. The "X" represents its ability to be combined with various technologies, such as TOPCon (tunneling oxide passivation contact) and HJT (heterojunction technology). Combining TOPCon with TOPCon technology creates a TBC, or combining HJT with TOPCon technology creates an HBC. XBC cells locate the PN junction and metal contacts on the back of the cell, while the front is covered with an anti-reflective passivation film. This prevents metal electrodes from obstructing the front surface, maximizes the use of incident light, reduces optical losses, and increases the effective power generation area, thereby achieving high conversion efficiency and enhancing the appearance of the cell assembly.

[0055] The above solution utilizes the back glass 200 provided with a prefabricated circuit to realize the interconnection of multiple battery cells 600, which can eliminate the soldering ribbon and the soldering ribbon welding process, thereby preventing the soldering ribbon from causing the battery cells 600 to warp or break, and can simplify the manufacturing process and improve processing efficiency; the back glass 200, the back film 400 and the battery cells 600 are stacked and assembled and then locally alloyed and welded, which can avoid thermal stress concentration, thereby preventing the battery cells 600 from warping or breaking.

[0056] Step S200: stacking multiple battery cells 600 provided with conductive solder joints 610 on the backside adhesive film 400, and then further comprising:

[0057] The battery cell 600 is pre-pressed with a preset pressure so that the distance between the conductive pad 211 and the conductive solder point 610 is less than or equal to a preset threshold.

[0058] For example, during the stacking process of the battery cells 600, the automated equipment moves the pre-arranged multiple battery cells 600 to the top of the back glass 200. After precise alignment, the automated equipment lowers the battery cells 600 to a height close to the back glass 200. The automated equipment then releases the battery cells 600, allowing them to land on the back glass 200 and contact the back adhesive film 400. Ideally, the conductive solder joints 610 of the battery cells 600 abut the conductive pads 211 on the back glass 200. However, in actual applications, a large gap may exist between the conductive solder joints 610 and the conductive pads 211, resulting in the conductive solder joints 610 and the conductive pads 211 being unable to connect with each other during the alloying process. Therefore, before the alloying process, lightly pressing the battery cells 600 with a preset pressure can reduce the distance between the conductive pads 211 and the conductive solder joints 610 to meet the gap requirements for the alloying process.

[0059] In a specific application example, pre-pressing the battery cell 600 with a preset pressure so that the distance between the conductive pad 211 and the conductive solder joint 610 is less than or equal to a preset threshold value includes:

[0060] The battery cell 600 is pre-pressed with a pressure of 1-2 N, so that the surface distance between the conductive pad 211 and the conductive solder point 610 is less than or equal to 50 μm.

[0061] For example, the pressure applied to the cell 600 needs to be able to reduce the distance between the conductive pad 211 and the conductive solder joint 610, while ensuring that the applied pressure is not too great to crush or damage the cell 600. The applied pressure can be 1N, 1.25N, 1.5N, or 2N, etc. The cell 600 is gently pressed with an appropriate pressure to reduce the surface distance between the conductive pad 211 and the conductive solder joint 610 to within 50μm, thereby ensuring that the conductive pad 211 and the conductive solder joint 610 are reliably connected during the alloying welding process.

[0062] Step S300, performing local alloying welding on the stacked back glass 200 and the battery cell 600, including:

[0063] Configure the heating parameters of the pulse hot press welding equipment;

[0064] Based on vision guidance, the pulse hot pressing welding equipment is controlled to locally heat the conductive pad 211 and the conductive solder joint 610 to perform alloying welding.

[0065] For example, pulsed hot pressing technology is used to locally alloy the conductive pads 211 and the conductive solder joints 610. Pulse hot pressing involves applying a pulsed voltage to a hot pressing head, causing the head to heat up. This heats the object connected to the hot pressing head, such as the hot pressing head in contact with the back glass 200. This heats the conductive pads 211 on the back glass 200 and causes them to melt, thereby achieving fusion welding. The heat-affected zone of this locally heated alloying welding technique is ≤0.5mm, effectively reducing the warpage of the cell 600 and, therefore, the fragmentation rate.

[0066] In a specific application example, the heating parameters include a temperature of 220~240℃, a pressure of 3~5N, and a heating time of 8~10s. Controlling the working temperature at 220~240℃ can reduce the heat of welding to a certain extent, and the heating time is 8~10 seconds, for example, 9 seconds. Shortening the heating time on the basis of ensuring that the melting depth of the solder joint is ≥70% can further reduce stress concentration. Applying a pressure of 3~5N, for example 4N, to the back glass 200 through the hot pressing head can enable the conductive pad 211 to be close to the conductive solder joint 610 after melting and connect to the conductive solder joint 610.

[0067] Step S300: performing partial alloying welding on the stacked back glass 200 and the battery cell 600 to obtain a first semi-finished product, which then includes:

[0068] The front adhesive film 300 and the front glass 100 are sequentially stacked on the surface of the battery cell 600 of the first semi-finished product to obtain a second semi-finished product.

[0069] For example, in the conventional lamination process, busbars 220 are used to weld the soldering ribbons before laminating and assembling the front film 300 and the front glass 100. In this embodiment, the back glass 200 achieves circuit interconnection through a prefabricated circuit. For example, the prefabricated circuit includes interconnecting interconnecting bars 210 and busbars 220. The conductive connection between the conductive pads 211 and the conductive contacts has been completed in the aforementioned steps. Thus, the basic circuit of the photovoltaic cell is already connected, and the first semi-finished product, the front film 300, and the front glass 100 can be laminated and pressed together. Compared to conventional processes, the method of this embodiment can eliminate the welding process between the busbars 220 and the soldering ribbons, which helps save materials and shorten production time, thereby reducing production costs and improving production efficiency. Both the front film 300 and the front glass 100 can be made of conventional materials. For example, the material of the front film 300 is the same as that of the back film 400, and the material of the front glass 100 is the same as that of the back glass 200. It is worth mentioning that no circuit structure is provided on the front glass 100 of this embodiment, and therefore the alignment accuracy requirements between the front glass 100 and the battery cell 600 and the back glass 200 can be reduced.

[0070] The above step of sequentially stacking the front adhesive film 300 and the front glass 100 on the surface of the first semi-finished product battery piece 600 to obtain a second semi-finished product further comprises:

[0071] Filling the gap between the back glass 200 and the battery piece 600 with an elastic buffer pad or coating buffer glue.

[0072] For example, filling the gap between the battery piece 600 and the back glass 200 with an elastic buffer pad can form a stress release layer after curing after lamination, which can effectively prevent the battery piece 600 from warping. The elastic buffer pad is made of silicone sheet with a thickness of 0.1-0.2 mm and a hardness of 50-60 Shore A (Shore A type). Alternatively, the gap between the edge of the battery piece 600 and the pre-prepared circuit of the back glass 200 is pre-coated with buffer glue, which fills the gap during lamination and forms a buffer layer after curing. The hardness of the buffer layer is 40-50 Shore A, which prevents mechanical stress concentration. The buffer glue can be made of silicone rubber with a viscosity of 500-800 cP (centipoise). By filling the gap and cooperating with the segmented pressure loading, the uniformity of the lamination pressure can be effectively improved, and the internal residual stress can be reduced to below 5 MPa, which is much lower than the traditional process of ≥15 MPa, which is beneficial to improve the mechanical load capacity and prevent the battery piece 600 from warping.

[0073] The above step of sequentially stacking the front adhesive film 300 and the front glass 100 on the surface of the first semi-finished product battery piece 600 to obtain a second semi-finished product further comprises:

[0074] The second semi-finished product is sent to a lamination device.

[0075] The lamination device is controlled based on a segmented pressure loading method to press the second semi-finished product to obtain a third semi-finished product.

[0076] For example, the segmented pressure loading method refers to dividing the loading process into multiple stages to achieve gradual loading, which avoids the phenomenon of excessive pressure in one-time loading causing the conductive welding points 610 of the battery piece 600 and the conductive pads 211 of the back glass 200 to appear to be detached or cracked, which is beneficial to ensure product quality.

[0077] The above step of controlling the lamination device to press the second semi-finished product based on the segmented pressure loading method comprises:

[0078] The lamination device is controlled to enter a vacuum state and maintain for a first predetermined time period.

[0079] Controlling the laminating equipment to increase the pressure in stages, wherein the pressure is increased to a first pressure value and maintained for a second preset time in the first stage, the pressure is increased to a second pressure value and maintained for a third preset time in the second stage, and the pressure is increased to a third pressure value and maintained for a fourth preset time in the third stage, and the second preset time, the third preset time, and the fourth preset time are shortened in sequence;

[0080] The laminating device is controlled to enter a pressure holding state and maintain the state for a fifth preset time, and the temperature of the pressure holding state is maintained at 140-160° C.

[0081] For example, after the second semi-finished product enters the laminating device, the laminating device is controlled to enter a vacuum state, the pressure value of the vacuum state is ≤5Pa, and the first preset time is maintained, for example, 5 minutes, to remove the air in the gaps of the second semi-finished product. After the vacuum stage ends, the pressure boosting stage is entered. The pressure boosting stage is divided into three small stages. The pressure value is increased from the vacuum pressure value to the target pressure value. The target pressure value can be adjusted according to actual application requirements. After reaching the target pressure value, the laminating device is controlled to enter a pressure holding state and maintain a suitable temperature so that the second semi-finished product can be pressed under suitable pressure and temperature conditions. The fifth preset time can be adjusted according to the material properties of the back film 400 and the front film 300. For example, for EVA film, the fifth preset time is 18 minutes.

[0082] In a specific application example, assuming the target pressure is 0.8 MPa, the lamination equipment is controlled to increase the pressure in stages, including:

[0083] Control the first stage pressure value of the lamination equipment to increase from the vacuum pressure value to 0.3 MPa and maintain it for 5 minutes;

[0084] Control the second stage pressure value of the lamination equipment to increase to 0.6 MPa and maintain it for 3 minutes;

[0085] The third stage pressure value of the laminating equipment was controlled to increase to 0.8 MPa and maintained for 2 minutes.

[0086] For example, the above-mentioned pressure boost control can gradually reduce the maintenance time of the pressure values ​​in different stages by loading the pressure in stages, so that the third semi-finished product can slowly adapt to the pressure changes during the pressurization process, ensuring product quality while taking into account production efficiency.

[0087] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. A method for preparing a photovoltaic cell stack assembly, characterized in that: include: The back adhesive film (400) with a pre-opened window is stacked on the back glass (200), the back glass (200) is provided with a prefabricated circuit, the prefabricated circuit is provided with a conductive pad (211), and the window position (410) of the back adhesive film (400) is adapted to the conductive pad (211); Stacking a plurality of battery cells (600) provided with conductive solder joints (610) on the back adhesive film (400), wherein the positions of the conductive solder joints (610) and the conductive pads (211) are adapted to each other; Pre-pressing the battery cell (600) with a pressure of 1 to 2 N so that the surface spacing between the conductive pad (211) and the conductive solder point (610) is less than or equal to 50 μm; The stacked back glass (200) and the battery cell (600) are locally alloyed and welded to obtain a first semi-finished product.

2. The photovoltaic cell stacking assembly preparation method according to claim 1, characterized in that: The locally alloying welding of the stacked back glass (200) and the battery cell (600) comprises: Configure the heating parameters of the pulse hot press welding equipment; The pulse hot pressing welding device is controlled based on visual guidance to locally heat the conductive pad (211) and the conductive welding point (610) to perform alloying welding.

3. The photovoltaic cell stacking assembly preparation method according to claim 2, characterized in that: The heating parameters include a temperature of 220-240° C., a pressure of 3-5 N, and a heating time of 8-10 s.

4. The photovoltaic cell stacking assembly preparation method according to claim 1, characterized in that: The stacked back glass (200) and the battery cell (600) are locally alloyed and welded to obtain a first semi-finished product, and then further comprises: A front adhesive film (300) and a front glass (100) are sequentially stacked on the surface of the battery cell (600) of the first semi-finished product to obtain a second semi-finished product.

5. The photovoltaic cell stacking assembly preparation method according to claim 4, characterized in that: The front adhesive film (300) and the front glass (100) are sequentially stacked on the surface of the battery cell (600) of the first semi-finished product to obtain a second semi-finished product, and then further comprising: The gap between the back glass (200) and the battery cell (600) is filled with an elastic buffering gasket or coated with buffering glue.

6. The photovoltaic cell stacking assembly preparation method according to claim 4 or 5, characterized in that: The front adhesive film (300) and the front glass (100) are sequentially stacked on the surface of the battery cell (600) of the first semi-finished product to obtain a second semi-finished product, and then further comprising: feeding the second semi-finished product into a laminating device; The laminating device is controlled based on a segmented pressure loading method to press the second semi-finished product to obtain a third semi-finished product.

7. The photovoltaic cell stacking assembly preparation method according to claim 6, characterized in that: The step of controlling the laminating device to press the second semi-finished product based on the segmented pressure loading method includes: Controlling the laminating device to enter a vacuum state and maintain the vacuum state for a first preset time period; Controlling the laminating device to increase pressure in stages, wherein the pressure is increased to a first pressure value and maintained for a second preset time in the first stage, the pressure is increased to a second pressure value and maintained for a third preset time in the second stage, and the pressure is increased to a third pressure value and maintained for a fourth preset time in the third stage, wherein the second preset time, the third preset time, and the fourth preset time are shortened in sequence; The laminating device is controlled to enter a pressure holding state and maintain the state for a fifth preset time, wherein the temperature of the pressure holding state is maintained at 140-160° C.

8. The photovoltaic cell stacking assembly preparation method according to claim 7, characterized in that: The step of controlling the laminating device to perform phased pressure boosting comprises: Controlling the first stage pressure value of the laminating device to increase from the vacuum pressure value to 0.3 MPa and maintain it for 5 minutes; Control the second stage pressure value of the laminating device to increase to 0.6 MPa and maintain it for 3 minutes; The third stage pressure value of the laminating device was controlled to increase to 0.8 MPa and maintained for 2 minutes.

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