A method for preparing a photovoltaic module and the photovoltaic module

Abstract

This application relates to a method for manufacturing a photovoltaic module and the photovoltaic module itself. The method for manufacturing a photovoltaic module includes: preheating the solar cells; pre-welding the solder ribbons to the solar cells to form a cell string; placing a carrier film on the side of the cell string where the solder ribbons are located; stacking a front cover plate, a front adhesive film, the cell string, a back adhesive film, and a backsheet to form a laminate; and laminating the laminate to complete the welding of the solder ribbons to the solar cells. Pre-welding the solder ribbons to the solar cells can initially fix the relative positions of the solder ribbons and the solar cells, reducing the possibility of displacement of the solder ribbons during the laying of the carrier film. It also reduces the possibility of gaps between the solder ribbons and the grid lines of the solar cells. During EL testing, it can reduce the possibility of blackening, streaks, and other phenomena, making it easier to determine whether there are defects such as microcracks or broken cells in the solar cells, thus improving the yield of the module.

Description

Technical Field

[0001] This application relates to the technical field of photovoltaic power generation, and in particular to a method for preparing a photovoltaic module and a photovoltaic module. Background Technology

[0002] A photovoltaic (PV) module comprises multiple solar cells that convert sunlight into electrical energy. These cells are connected by solder ribbons, and the electrical energy generated within each cell is conducted to busbars via the ribbons. The busbars then transmit the electrical energy out of the PV module. In existing technologies, a coating process can be used to connect the solder ribbons and solar cells. However, during this process, the solder ribbons are prone to displacement, and they may not fully adhere to the grid lines within the solar cell. During electroluminescence (EL) testing, the grid lines not adhered to the solder ribbon will appear as blackened or streaked shadows, making it impossible for EL testing to determine if there are microcracks, broken cells, or other defects at these locations. Summary of the Invention

[0003] In view of this, this application provides a method for preparing a photovoltaic module and a photovoltaic module to solve the problem of easy displacement of the solder strip during the coating process.

[0004] In a first aspect, embodiments of this application provide a method for preparing a photovoltaic module, the method comprising:

[0005] Preheat the battery cells;

[0006] The solder strips are pre-welded to the battery cells to form a battery string;

[0007] A carrier film is provided on the side of the battery string where the solder strip is provided;

[0008] The front cover plate, the front adhesive film, the battery string, the back adhesive film, and the back plate are stacked to form a laminated component.

[0009] The laminated components are laminated, and the solder strips are welded to the battery cells.

[0010] In one possible embodiment, the preparation method includes preheating the battery cells:

[0011] The battery cell is heated to the preheating temperature and maintained for 20 to 30 seconds.

[0012] In one possible embodiment, the preheating temperature is lower than the melting point of the solder strip.

[0013] In one possible embodiment, the preparation method includes pre-welding the solder strip to the battery cell to form a battery string.

[0014] The battery cell is heated to the melting point of the solder strip for a duration of less than or equal to 1 second.

[0015] In one possible embodiment, the solder strip includes a first body portion and a second body portion, the second body portion being disposed around the first body portion, the first body portion being a conductive material, and the second body portion being a welding material; during the pre-welding of the solder strip to the battery cell, the side of the second body portion closer to the battery cell melts, and the melted portion is 20% to 50% of the second body portion.

[0016] In one possible embodiment, after heating the battery cell to the melting point of the solder strip for a duration of less than or equal to 1 second, the preparation method includes:

[0017] The battery string is cooled to solidify the second main body, thereby connecting the solder strip to the battery cell.

[0018] In one possible embodiment, when a carrier film is disposed on the side of the battery string where the solder strip is provided, the preparation method includes:

[0019] The carrier film is laid on the side of the battery string where the welding strip is located;

[0020] The battery string is heated to 70°C to 80°C and held for 3 to 8 seconds to melt the carrier film.

[0021] In one possible embodiment, the size of the carrier film is greater than or equal to the size of the battery cell, but smaller than the size of the battery string, and multiple carrier films are disposed on the battery string, with each carrier film capable of covering a single battery cell in the battery string; or, the size of the carrier film is greater than or equal to the size of the battery string, and the carrier film is capable of covering multiple battery cells in the battery string.

[0022] In one possible embodiment, when the solder strips are welded to the battery cells during the lamination of the laminate, the preparation method includes:

[0023] The laminate is heated to a lamination temperature greater than or equal to the melting point of the solder strip.

[0024] Secondly, embodiments of this application also provide a photovoltaic module, which is prepared by any of the preparation methods described above.

[0025] This application relates to a method for manufacturing a photovoltaic module and the photovoltaic module itself. The method for manufacturing a photovoltaic module includes: preheating the solar cells; pre-welding the solder ribbons to the solar cells to form a cell string; placing a carrier film on the side of the cell string where the solder ribbons are located; stacking a front cover plate, a front adhesive film, the cell string, a back adhesive film, and a backsheet to form a laminate; and laminating the laminate to complete the welding of the solder ribbons to the solar cells. Pre-welding the solder ribbons to the solar cells can initially fix the relative positions of the solder ribbons and the solar cells, reducing the possibility of displacement of the solder ribbons during the laying of the carrier film. It also reduces the possibility of gaps between the solder ribbons and the grid lines of the solar cells. During EL testing, it can reduce the possibility of blackening, streaks, and other phenomena, making it easier to determine whether there are defects such as microcracks or broken cells in the solar cells, thus improving the yield of the module. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A flowchart of a photovoltaic module fabrication method provided in the embodiments of this application;

[0028] Figure 2 This is a schematic diagram of the structure of the photovoltaic module manufacturing method provided in this application, in which the solder ribbon is laid on the battery cell;

[0029] Figure 3 This is a schematic diagram of the structure after pre-welding of the solder strip in the photovoltaic module manufacturing method provided in the embodiments of this application;

[0030] Figure 4 This is a schematic diagram of the structure after the carrier film is laid in the photovoltaic module manufacturing method provided in the embodiments of this application;

[0031] Figure 5 This is a schematic diagram of the structure of the carrier film after melting in the photovoltaic module manufacturing method provided in the embodiments of this application;

[0032] Figure 6 This is a schematic diagram of the structure of the laminated component provided in the embodiments of this application;

[0033] Figure 7 This is a schematic diagram of the structure of the laminated components in the photovoltaic module manufacturing method provided in this application embodiment.

[0034] Figure label:

[0035] 1-Battery cell;

[0036] 2-Welding strip;

[0037] 21-First Main Body Section;

[0038] 22-Second main body section;

[0039] 3-Carrier membrane;

[0040] 4-Front cover;

[0041] 5- Front adhesive film;

[0042] 6- Backing adhesive film;

[0043] 7-Back panel. Detailed Implementation

[0044] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0045] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0046] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0047] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0048] For grid-less solar cells, the surface of cell 1 lacks a main grid. After multiple cells 1 are welded together, the solder ribbon 2 replaces the original main grid and directly connects to the fine grid, reducing silver paste consumption and lowering the production cost of cell 1. Grid-less solar cells reduce the light-shielding area of ​​the grid lines in cell 1 and reduce fine grid transmission losses, thereby increasing the total power of the module. Simultaneously, the increased number of fine grid contact points reduces the risk of microcracks in the thin silicon wafer, improving yield and reliability.

[0049] The fabrication method of the gridless module in the relevant technology is as follows: A solder ribbon 2 is laid on the solar cell 1, and then a carrier film 3 is used to fix the solder ribbon 2 onto the solar cell 1, so that multiple solar cells 1 form a cell string. Finally, it is laminated with a backsheet 7, an encapsulating film, and photovoltaic glass to form a gridless photovoltaic module. Before the carrier film 3 fixes the solder ribbon 2 to the solar cell 1, the solder ribbon 2 is prone to misalignment. Furthermore, the carrier film 3 cannot guarantee that the solder ribbon 2 and the grid lines are completely bonded, resulting in gaps between the solder ribbon 2 and some grid lines. During EL testing, blackening and striped shadows will appear at the locations with gaps. It is difficult to determine whether there are microcracks, broken cells, or other defects in the solar cell 1 at the blackened or striped areas, leading to a loss of module yield.

[0050] This application provides a method for manufacturing a photovoltaic module to improve the welding effect between the solder ribbon 2 and the cell 1. The above manufacturing method does not limit the type of cell 1. The types of cell 1 include, but are not limited to, passivated emitter rear cell (PERC), tunnel oxide passivated contact cell (TOPCon), intrinsic thin-film heterojunction cell (HJT), interdigitated back contact cell (IBC), perovskite cell, etc.

[0051] For PERC cells, along their thickness direction, the PERC cell sequentially includes a front-surface silver electrode, a front-surface silicon nitride passivation layer, a phosphorus emitter layer, a P-type substrate silicon layer, a localized aluminum back field, a metallic aluminum back electrode, and a back passivation layer (Al2O3 / SiNx). PERC cells use a passivation film to passivate the back side, replacing the all-aluminum back field, enhancing light reflection within the silicon substrate, reducing the recombination rate on the back side, and improving the cell efficiency by 0.5%-1%.

[0052] For a TOPCon cell, along its thickness direction, it sequentially comprises a silver electrode, a front-surface silicon nitride passivation layer, a boron-doped emitter, an N-type substrate silicon layer, a diffused doped layer, an ultrathin silicon oxide layer, doped polycrystalline silicon, silicon nitride, and the silver electrode. The back of the cell consists of an ultrathin silicon oxide layer (1nm–2nm) and a phosphorus-doped microcrystalline amorphous mixed Si film, which together form a passivation contact structure. This structure blocks minority carrier recombination, increasing the cell's open-circuit voltage and short-circuit current. The ultrathin oxide layer allows majority carrier electrons to tunnel into the polycrystalline silicon layer while simultaneously blocking minority carrier recombination. The excellent passivation effect of the ultrathin silicon oxide and heavily doped silicon film causes band bending on the silicon wafer surface, creating a field passivation effect. This significantly increases the probability of electron tunneling, reduces contact resistance, and improves the cell's open-circuit voltage and short-circuit current, thereby enhancing the cell's conversion efficiency.

[0053] For an HJT cell, along its thickness direction, the HJT cell sequentially includes a front low-temperature silver electrode, a front conductive film, an N-type amorphous silicon film, an intrinsic amorphous silicon film, an N-type substrate silicon layer, an intrinsic amorphous silicon film, a P-type amorphous silicon film, a back conductive film, and a back low-temperature silver electrode.

[0054] For an IBC cell, along its thickness direction, it sequentially includes a silicon nitride inversion layer, an N+ front surface field, an N-type substrate silicon layer, a P+ emitter, an N+ back field, an aluminum oxide passivation layer, a silicon nitride antireflection layer, and a silver electrode. IBC cells utilize ion implantation technology to obtain P- and N-regions with good uniformity and precisely controllable junction depth. The absence of grid lines on the front side eliminates light-blocking current loss from the metal electrodes, maximizing the utilization of incident photons and improving short-circuit current by approximately 7% compared to conventional solar cells. Due to its back-contact structure, grid line shading is not a concern, allowing for a wider grid line ratio, thus reducing series resistance and achieving a high fill factor. Optimized design of surface passivation and light-trapping structures can be achieved, resulting in lower front surface recombination rates and surface reflection.

[0055] For a perovskite solar cell, along its thickness direction, it sequentially comprises a substrate material, a conductive thin film, an electron transport layer (titanium dioxide), a perovskite absorption layer (hole transport layer), and a metal cathode. Perovskite materials possess a high light absorption coefficient and a long carrier diffusion distance. After the photons absorbed by the perovskite material are converted into electrons, they are easily collected by the electrodes with minimal loss, thus generating high photogenerated voltage and current, resulting in high photoelectric conversion efficiency.

[0056] like Figures 1 to 7 As shown, the preparation method provided in this application includes:

[0057] S1. Preheat battery cell 1;

[0058] S2. Pre-weld the welding strip 2 to the battery cell 1 to form a battery string;

[0059] S3. A carrier film 3 is provided on the side of the battery string where the welding strip 2 is provided;

[0060] S4. Stack the front cover plate 4, the front adhesive film 5, the battery string, the back adhesive film 6, and the back plate 7 to form a laminated component.

[0061] S5, laminating and stacking components to complete the welding of the welding strip 2 and the battery cell 1.

[0062] After the solder ribbon 2 is laid on the solar cell 1, it is pre-welded to the solar cell 1. This pre-fixes the relative position of the solder ribbon 2 and the solar cell 1, reducing the possibility of the solder ribbon 2 shifting during the laying of the carrier film 3. During pre-welding, the solder ribbon 2 can also form a certain alloy with the grid lines of the solar cell, reducing the possibility of gaps between the solder ribbon 2 and the grid lines of the solar cell 1. During EL testing, this reduces the possibility of blackening, streaky shadows, etc., making it easier to determine whether there are defects such as microcracks or broken cells in the solar cell 1, thus improving the yield of the module. Laying the carrier film 3 on the side of the solar cell 1 where the solder ribbon 2 is located further restricts the relative position of the solder ribbon 2 and the solar cell 1, reducing the possibility of the solder ribbon 2 shifting during the stacking and lamination process.

[0063] like Figure 2 As shown, the welding strip 2 includes a first main body portion 21 and a second main body portion 22, wherein the first main body portion 21 is a conductive material and the second main body portion 22 is a welding material, and the second main body portion 22 is disposed around the first main body portion 21.

[0064] When the solder ribbon 2 is soldered to the solar cell 1, the second main body 22 melts and solidifies, fixing the solder ribbon 2 to the solar cell 1 to connect multiple solar cells 1. The solder ribbon 2 also enables the multiple solar cells 1 to be electrically connected. The electrical energy generated in the solar cell 1 is transmitted through the solder ribbon 2 to the busbar in the photovoltaic module, and then transmitted out of the photovoltaic module through the busbar. The grid line material on the solar cell 1 is silver, and the second main body 22 can be a tin layer. After the tin layer is heated and melted, it can alloy with silver, reducing the resistance between the solder ribbon 2 and the solar cell 1, facilitating the transmission of the current generated in the solar cell 1 to the second main body 22 of the solder ribbon 2. The current generated in the solar cell 1 is conducted through the second main body 22 to the first main body 21. The first main body 21 can be a copper core. The copper core has low resistance, reducing the loss of electrical energy generated by the solder ribbon 2 on the solar cell 1 when the electrical energy is transmitted from the solder ribbon 2 to the busbar.

[0065] The preparation method for preheating battery cell 1 includes:

[0066] S11. Heat the battery cell 1 to the preheating temperature and maintain it for 20 to 30 seconds.

[0067] When welding the welding ribbon 2 and the battery cell 1, a higher temperature is required. The battery cell 1 is preheated for 20 to 30 seconds to allow it to adapt to the preheated temperature. When welding the welding ribbon 2 and the battery cell 1, the temperature difference between the battery cell 1 and the welding temperature is reduced. This reduces the possibility of thermal stress caused by large temperature changes in the battery cell 1, thereby reducing the risk of damage to the battery cell 1 during welding.

[0068] The heating element can be set inside the platform for transporting or placing the battery cell 1. Placing the battery cell 1 on the platform surface will preheat the battery cell 1. The heating element can also be a heating lamp tube set above the platform. After the battery cell 1 is placed on the platform surface, the heating lamp tube is turned on to heat the battery cell 1. The battery cell 1 can also be preheated by other means.

[0069] In one possible embodiment, the preheating temperature is lower than the melting point of the solder strip 2.

[0070] Taking the second main body portion 22 of the solder ribbon 2 as an example, the lower limit of the melting point of the solder layer is between 150°C and 170°C. After the battery cell 1 is preheated, the solder ribbon 2 needs to be laid on the side of the battery cell 1 with the grid lines. At this time, the second main body portion 22 of the solder ribbon 2 is in contact with the battery cell 1. The preheating temperature of the battery cell 1 can be 135°C, which is lower than the melting point of the second main body portion 22 in the solder ribbon 2. When the second main body portion 22 in the solder ribbon 2 is in contact with the battery cell 1, the possibility of the second main body portion 22 melting can be reduced, making it easier to lay the solder ribbon 2 to the preset position. If the second main body portion 22 of the solder ribbon 2 is made of other welding materials, the heating temperature during the preheating of the battery cell 1 needs to be determined according to the specific material of the second main body portion 22. The heating temperature should be lower than the melting point of the second main body portion 22.

[0071] like Figure 3 As shown, the preparation method for pre-welding the solder strip 2 to the battery cell 1 to form a battery string includes:

[0072] S21. Heat the battery cell 1 to the melting point of the solder strip 2 for a duration of less than or equal to 1 second.

[0073] Taking the second main body 22 of the solder ribbon 2 as an example, the lower limit of the melting point of the solder layer is between 150°C and 170°C. After the solder ribbon 2 is laid to the preset position, the heating temperature can be between 150°C and 170°C to reach the lower limit of the melting point of the second main body 22 in the solder ribbon 2, so that the second main body 22 begins to melt. However, the melting speed is small and the heating time is less than or equal to 1 second, so as to control the quality of the melted part in the second main body 22. The melted part enables the solder ribbon 2 to be pre-welded to the battery cell 1 and can achieve a certain alloying with the grid line of the battery cell 1. If the heating temperature is less than 150℃, the second main body 22 of the solder ribbon 2 cannot melt and cannot be welded to the battery cell 1. If the heating temperature is greater than 170℃, the second main body 22 of the solder ribbon 2 melts too quickly, making it difficult to control the melting quality of the second main body 22. This results in difficulty controlling the degree of alloying between the solder ribbon 2 and the grid line during pre-welding. After lamination, the solder ribbon 2 will continue to melt and further alloy with the grid line. Excessive alloying can lead to grid line breakage. Therefore, the heating temperature can be 150℃, 160℃, 170℃, etc. If the second main body 22 of the solder ribbon 2 is made of other welding materials, the heating temperature during pre-welding needs to be determined according to the specific material of the second main body 22.

[0074] The melting of the side of the second main body 22 that contacts the cell 1 allows the solder ribbon 2 to be pre-welded to the cell 1, which can reduce the possibility of gaps between the solder ribbon 2 and the grid lines of the cell 1. In EL testing, this can reduce the occurrence of blackening and striped shadows, which would otherwise make it impossible to determine whether there are defects such as hidden cracks or broken pieces in the cell 1 at the blackened or striped shadow areas. This is beneficial to improving the yield of photovoltaic modules after EL testing.

[0075] The preparation method includes heating the battery cell 1 to the melting point of the solder strip 2 for a duration of less than or equal to 1 second.

[0076] S22. Cool down the battery cell 1 to solidify the second main body 22, so as to connect the solder strip 2 and the battery cell 1.

[0077] After the second main body 22 in the welding ribbon 2 partially melts, the battery cell 1 is cooled to below the melting point of the second main body 22, and the second main body 22 is solidified, so that the welding ribbon 2 can be fixed to the battery cell 1 through the second main body 22. During the laying of the carrier film 3 and the stacking process, the possibility of the welding ribbon 2 shifting is reduced.

[0078] After multiple battery cells 1 are welded into a battery string by welding ribbons 2, a carrier film 3 needs to be laid on the side of the battery cell 1 where the welding ribbons 2 are located. The melting point of the carrier film 3 is lower than the melting point of the second main body 22 in the welding ribbons 2. When the second main body 22 is solidified, the temperature of the battery cell 1 is reduced to below the melting point of the carrier film 3. When laying the carrier film 3, the possibility of the carrier film 3 melting upon contact with the welding ribbons 2 is reduced, making it easier to lay the carrier film 3.

[0079] like Figure 3 As shown, in one possible embodiment, when the solder strip 2 is pre-welded to the battery cell 1, the side of the second main body 22 near the battery cell 1 melts, and the melted portion accounts for 20% to 50% of the second main body 22.

[0080] The solder ribbon 2 is pre-welded to the battery cell 1 to reduce the possibility of solder ribbon 2 displacement. If less than 20% of the second main body 22 melts during pre-welding, the contact area between the second main body 22 and the battery cell 1 is small. After curing, this reduces the stability of the solder ribbon 2 after pre-welding, making it prone to displacement during the laying of the carrier film 3. The lamination process temperature is higher than the melting point of the second main body 22, which will cause the second main body 22 to melt further. The material of the second main body 22 is tin, and the material of the grid line is silver. When tin and silver undergo an alloy reaction... Silver will be consumed during the process. If more than 50% of the second main body 22 is melted during pre-welding, too much of the second main body 22 will melt after lamination, resulting in a greater degree of alloying with the grid lines. This will lead to excessive silver consumption. During lamination, the degree of alloying between the solder ribbon and the grid lines will continue to increase, which may easily lead to grid line breakage. Therefore, during pre-welding, the melted portion of the second part is 20%, 35%, 50%, etc., to make the position of the solder ribbon 2 on the cell 1 more stable after pre-welding. This will also reduce the possibility of grid line breakage on the cell 1 after lamination.

[0081] like Figure 4 and Figure 5 As shown, in one possible embodiment, when a carrier film 3 is disposed on the side of the battery string where the solder strip 2 is disposed, the preparation method includes:

[0082] S31. Lay the carrier film 3 on the side of the battery cell 1 where the welding strip 2 is located;

[0083] S32. Heat the battery string to 70°C to 80°C and continue for 3 to 8 seconds to melt the carrier membrane 3;

[0084] S33. Cool the battery string to below the melting point of the carrier film 3 to solidify the carrier film 3.

[0085] A carrier film 3 is laid on the side of the solar cell 1 where the solder ribbon 2 is located, with the solder ribbon 2 positioned between the carrier film 3 and the solar cell 1. After the carrier film 3 melts, it adheres to the solar cell 1, which restricts the relative position between the solder ribbon 2 and the solar cell 1, further reducing the possibility of solder ribbon 2 displacement and improving the reliability of the photovoltaic module. The solar cell string is heated to 70°C to 80°C to melt the carrier film 3 for 3 to 8 seconds. The melted carrier film 3 comes into contact with the solar cell 1, and the thickness of the melted carrier film 3 is greater than the thickness of the solder ribbon 2, allowing the carrier film 3 to wrap the solder ribbon 2. After the carrier film 3 solidifies, it adheres to the solar cell 1, fixing the solder ribbon 2 between the solar cell 1 and the carrier film 3, further improving the stability of the solder ribbon 2.

[0086] In one possible embodiment, the size of the carrier film is greater than or equal to the size of the battery cell 1, but smaller than the size of the battery string. A single carrier film 3 can cover the side of a single battery cell 1 where the solder strip 2 is provided. Multiple carrier films 3 are provided on the battery string so that each battery cell 1 can be covered with a carrier film 3.

[0087] A carrier film 3 is laid on the side of the battery cell 1 where the solder ribbon 2 is located. The size of the carrier film 3 is greater than or equal to the size of the battery cell 1, so that the carrier film 3 can completely cover the battery cell 1 after melting, thereby limiting the relative position between the solder ribbon 2 and the battery cell 1. A single carrier film 3 is provided on the side of a single battery cell 1 where the solder ribbon 2 is located, which can reduce the possibility of air bubbles forming between the carrier film 3 and the battery cell 1.

[0088] In one possible embodiment, the size of the carrier film 3 is greater than or equal to the size of the battery string. A single carrier film 3 is laid on the side of the battery string where the solder strip 2 is provided, which can cover multiple battery cells 1 in the battery string.

[0089] After the solar cells 1 and the welding ribbon 2 are pre-welded to form a solar cell string, a carrier film 3 is laid. The size of the carrier film 3 is greater than or equal to the size of the solar cell string. A single carrier film 3 can be laid on the side of the solar cell string where the welding ribbon 2 is located to cover multiple solar cells 1 in the solar cell string. This simplifies the process of laying the carrier film 3 and helps to improve the production efficiency of photovoltaic modules.

[0090] The placement of the grid lines in different types of solar cells 1 varies, and the placement of the solder ribbons 2 also changes accordingly. Taking TOPCon and BC cells as examples: In TOPCon cells, the grid lines are located on the front and back sides of the solar cell 1. When multiple TOPCon solar cells 1 are connected in series, solder ribbons 2 are needed to connect the grid lines on the front side of one solar cell 1 to the grid lines on the back side of another solar cell 1. Therefore, solder ribbons 2 are provided on both the front and back sides of the solar cell 1. After forming the battery string, a carrier film 3 needs to be laid on both the front and back sides of the solar cell 1 to reduce the possibility of displacement of the solder ribbons 2 on the front and back sides of the solar cell 1. Figures 2 to 7 As shown, the P / N junction, substrate, and emitter contact electrodes of the BC cell are arranged in an interdigitated shape on the back of the cell, so that the grid lines of the BC cell are all located on the back of the cell. When multiple BC cells 1 are connected in series, the solder ribbons 2 are all set on the back of the cell 1. After the cell string is formed, only the carrier film 3 needs to be laid on the back of the cell 1 to reduce the possibility of the solder ribbons 2 on the back of the cell 1 shifting, reduce the difficulty of laying the carrier film 3, and improve the production efficiency of photovoltaic modules.

[0091] like Figure 6 and Figure 7 As shown, in one possible embodiment, when welding the solder strip 2 to the battery cell 1 in the laminated stack, the preparation method includes:

[0092] S51. Heat the laminated parts to the lamination temperature, which is greater than or equal to the melting point of the solder strip 2.

[0093] Before lamination, the second main body portion 22 in the solder ribbon 2 partially melts and forms a certain alloy with the grid lines in the cell 1. At this time, the stability of the solder ribbon 2 and the conductivity between the solder ribbon 2 and the grid lines are both poor. When the laminated components are heated to a temperature higher than the melting point of the second main body portion 22, the second main body portion 22 in the solder ribbon 2 is completely melted. This improves the welding strength between the solder ribbon 2 and the cell 1, and also improves the degree of alloying between the second main body portion 22 and the grid lines, thereby improving the conductivity between the cell 1 and the grid lines, and ultimately improving the power generation efficiency of the photovoltaic module.

[0094] This application also provides a photovoltaic module. The photovoltaic module is prepared by the above-described preparation method, which can reduce the possibility of misalignment of the solder ribbon 2 or gaps between the solder ribbon 2 and the grid lines of the cell 1. During EL testing, it can reduce the possibility of blackening, strip shadows and other phenomena, making it easier to judge whether there are defects such as microcracks or broken cells in the cell 1, and improving the yield of the module.

[0095] This application relates to a method for manufacturing a photovoltaic module and the photovoltaic module itself. The method for manufacturing a photovoltaic module includes: preheating a solar cell 1; pre-welding a solder ribbon 2 to the solar cell 1 to form a cell string; placing a carrier film 3 on the side of the cell string where the solder ribbon 2 is located; stacking a front cover plate 4, a front adhesive film 5, the cell string, a back adhesive film 6, and a backsheet 7 to form a laminate; and laminating the laminate to complete the welding of the solder ribbon 2 to the solar cell 1. Pre-welding the solder ribbon 2 to the solar cell 1 can initially fix the relative position of the solder ribbon 2 and the solar cell 1, reducing the possibility of the solder ribbon 2 shifting when the carrier film 3 is laid. It can also reduce the possibility of gaps between the solder ribbon 2 and the grid lines of the solar cell 1. During EL testing, it can reduce the possibility of blackening, streaks, and other phenomena, making it easier to judge whether there are defects such as microcracks or broken cells in the solar cell 1, thus improving the yield of the module.

Claims

1. A method for preparing a photovoltaic module, characterized in that, The preparation method includes: Preheat the battery cells; The solder strips are pre-welded to the battery cells to form a battery string; A carrier film is provided on the side of the battery string where the solder strip is provided; The front cover plate, the front adhesive film, the battery string, the back adhesive film, and the back plate are stacked to form a laminated component. The laminated components are laminated, and the solder strips are welded to the battery cells. The welding strip includes a first main body and a second main body, the second main body being disposed around the first main body, the first main body being a conductive material, and the second main body being a welding material; when the welding strip is pre-welded to the battery cell, the side of the second main body closer to the battery cell melts.

2. The method for preparing a photovoltaic module according to claim 1, characterized in that, When preheating the battery cells, the preparation method includes: The battery cell is heated to the preheating temperature and maintained for 20 to 30 seconds.

3. The method for preparing a photovoltaic module according to claim 1, characterized in that, The preheating temperature is lower than the melting point of the welding strip.

4. The method for preparing a photovoltaic module according to claim 1, characterized in that, When pre-welding the solder strip to the battery cell to form a battery string, the preparation method includes: The battery cell is heated to the melting point of the solder strip for a duration of less than or equal to 1 second.

5. The method for preparing a photovoltaic module according to claim 4, characterized in that, When the welding strip is pre-welded to the battery cell, the molten portion is 20% to 50% of the second main body.

6. The method for preparing a photovoltaic module according to claim 5, characterized in that, The preparation method includes heating the battery cell to the melting point of the solder strip for a duration of less than or equal to 1 second. The battery string is cooled to solidify the second main body, thereby connecting the solder strip to the battery cell.

7. The method for preparing a photovoltaic module according to claim 1, characterized in that, When a carrier film is disposed on the side of the battery string where the solder strip is provided, the preparation method includes: The carrier film is laid on the side of the battery string where the welding strip is located; The battery string is heated to 70°C to 80°C and held for 3 to 8 seconds to melt the carrier film.

8. The method for preparing a photovoltaic module according to claim 1, characterized in that, The size of the carrier film is greater than or equal to the size of the battery cell, but smaller than the size of the battery string. Multiple carrier films are disposed on the battery string, and a single carrier film can cover a single battery cell in the battery string; or, the size of the carrier film is greater than or equal to the size of the battery string, and the carrier film can cover multiple battery cells in the battery string.

9. The method for preparing a photovoltaic module according to claim 1, characterized in that, When the lamination of the laminate is completed and the solder strip is welded to the battery cell, the preparation method includes: The laminate is heated to a lamination temperature greater than or equal to the melting point of the solder strip.

10. A photovoltaic module, characterized in that, The photovoltaic module is prepared by any one of claims 1 to 9.

Images