Preparation method of photovoltaic module and photovoltaic module

Abstract

The invention relates to a preparation method of a photovoltaic module and the photovoltaic module. The preparation method of the photovoltaic module comprises the following steps: forming a main grid and a fine grid on a substrate of a battery piece; a patterned first insulating layer is arranged on the battery piece, so that at least part of the structure of the main grid is exposed out of the first insulating layer; forming a conductive structure on the main grid through an electroplating process; removing the first insulating layer; and electrically connecting the conductive structures of the adjacent battery pieces through connecting pieces. The conductive structures play a role in collecting, converging and transmitting the current of the main grid, the conductive structures of the adjacent battery pieces are electrically communicated through the connecting pieces, and the adjacent battery pieces are fixed through the connecting pieces, so that a welding strip does not need to be arranged between the battery pieces. The conductive structure is formed on the main grid through the electroplating process, so that series welding of the battery pieces is not needed, the problem of poor series return of the battery pieces is avoided, the yield of the photovoltaic module and the preparation efficiency of the photovoltaic module are improved, and the loss of the battery pieces is reduced.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a method for preparing a photovoltaic module and a photovoltaic module. Background Art

[0002] Photovoltaic modules are used to convert solar energy into electrical energy. At present, when preparing photovoltaic modules, multiple cells are usually connected into a cell string by using a string welding process. During the string welding process, it is easy to have problems such as cold welding between the welding ribbon and the grid line of the cell, and hidden cracks in the cell during the welding process, which affects the yield rate and production efficiency of photovoltaic modules. Summary of the invention

[0003] In view of this, the present application provides a method for preparing a photovoltaic module and a photovoltaic module, so as to solve the problem of poor series return occurring in the preparation process of the photovoltaic module in the prior art.

[0004] In a first aspect, an embodiment of the present application provides a method for preparing a photovoltaic module, wherein the photovoltaic module includes a cell, and the method for preparing the photovoltaic module includes: forming a main grid and a fine grid on the substrate of the cell; Disposing a patterned first insulating layer on the cell sheet so that at least a portion of the structure of the main grid is exposed from the first insulating layer; forming a conductive structure on the main grid by an electroplating process; removing the first insulating layer; The conductive structures of adjacent battery cells are electrically connected via connectors.

[0005] In a possible implementation manner, the step of forming a conductive structure on the main gate by an electroplating process includes: forming a conductive structure having a width greater than or equal to a width of the main gate.

[0006] In a possible implementation manner, the step of forming a conductive structure on the main grid by an electroplating process includes: forming a conductive structure with a thickness D1 satisfying: 0.05 mm≤D1≤0.3 mm.

[0007] In a possible implementation, before the step of electrically connecting the conductive structures of adjacent cells via connectors, the method for preparing the photovoltaic module includes: forming a protective layer on the conductive structure by an electroplating process.

[0008] In a possible implementation manner, the step of forming a conductive structure on the main grid by an electroplating process includes: electroplating copper on the main grid so that the conductive structure is a copper strip; The step of forming a protective layer on the conductive structure by an electroplating process includes: electroplating tin on the conductive structure so that the protective layer is a tin layer.

[0009] In a possible implementation, the method for preparing the photovoltaic module includes: forming the main grid and the fine grid on the substrate by an electroplating process.

[0010] In a possible implementation, the substrate of the cell includes a target area and a non-target area, and the method for preparing the photovoltaic module includes: Opening a slot in the target area; forming a seed layer in the target area and the non-target area; Disposing a second insulating layer in the non-target area; performing electroplating in the target area to form the main grid and the fine grid in the target area; The second insulating layer and the seed layer not in contact with the main gate and the fine gate are removed.

[0011] In a second aspect, an embodiment of the present application provides a photovoltaic module, which is prepared by the photovoltaic module preparation method described above.

[0012] In a possible embodiment, the photovoltaic module includes a cover plate, an encapsulation layer and a battery string, the encapsulation layer is located between the cover plate and the battery string, the cover plate is connected to the battery string through the encapsulation layer, wherein the battery string includes a plurality of battery cells, the battery cell having a main grid and a fine grid, the main grid is connected to a conductive structure on one side along the thickness direction of the battery cell, and the conductive structures of adjacent battery cells are electrically connected through a connector.

[0013] In a possible implementation, along the thickness direction of the battery cell, the projection of the main grid is located within the projection of the corresponding conductive structure, and the thickness D of the conductive structure satisfies: 0.05 mm≤D≤0.3 mm.

[0014] The embodiment of the present application provides a method for preparing a photovoltaic module and a photovoltaic module. The photovoltaic module includes a cell. The method for preparing the photovoltaic module includes: forming a main grid and a fine grid on the substrate of the cell; providing a patterned first insulating layer on the cell so that at least part of the structure of the main grid is exposed from the first insulating layer; forming a conductive structure on the main grid by an electroplating process; removing the first insulating layer; and electrically connecting the conductive structures of adjacent cells through a connector. The conductive structure collects, converges and transmits the current of the main grid. The conductive structures of adjacent cells are electrically connected through the connector, and the adjacent cells are fixed by the connector, so that no welding strip is required between the cells. The conductive structure is formed on the main grid by an electroplating process, so that the cell does not need to be soldered in series, avoiding the problem of poor series return of the cell, improving the yield of the photovoltaic module and the preparation efficiency of the photovoltaic module, and reducing the loss of the cell. On the other hand, the electroplating process is easy to implement and has low cost. The electroplating process realizes the stable and reliable connection between the conductive structure and the main grid, improves the stability and reliability of the photovoltaic module, and is conducive to simplifying the preparation process of the photovoltaic module and reducing the production cost of the photovoltaic module.

[0015] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 This is a flow chart of a method for preparing a photovoltaic module in one embodiment of the present application; Figure 2 It is a partial schematic diagram of a battery cell in one embodiment of the present application; Figure 3 This is a partial schematic diagram of a battery cell in another embodiment of the present application; Figure 4 This is a schematic diagram of conductive structures of adjacent battery cells connected by connecting members in one embodiment of the present application; Figure 5 Schematic diagram of a photovoltaic module in one embodiment of the present application.

[0018] Reference numerals: 100- Photovoltaic modules; 10-battery string; 11-battery cell; 111- main grid; 112-fine grid; 12- conductive structure; 13-Connector; 20- first cover plate; 30- second cover plate; 40-first encapsulation layer; 50 - second encapsulation layer. DETAILED DESCRIPTION

[0019] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0020] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0021] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0022] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0023] Photovoltaic modules are used to convert solar energy into electrical energy. Photovoltaic modules include a battery string, and the battery string includes multiple battery cells. At present, when preparing photovoltaic modules, multiple battery cells are connected by welding ribbons to form a battery string, that is, multiple battery cells are connected into a battery string using a string welding process. In the process of string welding, the problem of poor string return is prone to occur, for example, a cold weld occurs between the welding ribbon and the grid line of the battery cell, the battery cell has hidden cracks during the welding process, the main grid and the fine grid break during the welding process, etc., which affects the yield of the photovoltaic module and the production efficiency of the photovoltaic module. At the same time, the problem of poor string return will cause the battery cell to be damaged and unable to continue to be used, which increases the loss of the battery cell in the production process of the photovoltaic module, thereby increasing the production cost of the photovoltaic module.

[0024] Based on the above problems, Figure 1 As shown, the embodiment of the present application provides a method for preparing a photovoltaic module, comprising: Step S110: forming a main grid and a fine grid on the substrate of the cell.

[0025] Please also refer to Figure 2 The substrate of the cell 11 may be an N-type silicon substrate or a P-type silicon substrate. The N-type silicon substrate may be a silicon substrate doped with an N-type element, and the N-type element may be a pentavalent element such as phosphorus, arsenic or antimony. The P-type silicon substrate may be a silicon substrate doped with a P-type element, and the P-type element may specifically be a trivalent element such as boron, indium or gallium. The main grid 111 and the fine grid 112 may be prepared by metal slurry printing or electroplating, and the fine grid 112 may be used to collect and conduct the current on the cell 11. The main grid 111 is electrically connected to the fine grid 112, and it may be used to collect the current on the fine grid 112 for convergence.

[0026] In some embodiments, the battery cell can be a multi-busbar (MBB) battery cell, that is, multiple main grids are formed on the substrate of the battery cell. The multi-busbar technology can reduce the number of fine grids and reduce costs by increasing the number of main grids. At the same time, it can also shorten the current conduction path between the main grid and the fine grid to reduce power loss and thus increase the power of the battery cell.

[0027] After step S110 , the process proceeds to step S120 : providing a patterned first insulating layer on the cell, so that at least a portion of the structure of the main grid is exposed from the first insulating layer.

[0028] The first insulating layer can be formed on the battery cell by spraying or printing. The first insulating layer can be a film layer with insulating properties such as an insulating ink layer and an insulating glue layer. The first insulating layer has a hollow area, and the position of the hollow area corresponds to the position of the main grid on the battery cell, so that at least part of the structure of the main grid is exposed from the first insulating layer. In some embodiments, the pattern of the hollow area corresponds to the pattern of the main grid on the battery cell, so that the entire structure of the main grid can be exposed from the first insulating layer, and the area other than the main grid on the battery cell is covered by the first insulating layer. In other embodiments, the area of ​​the hollow area is smaller than the area of ​​the main grid, so that part of the structure of the main grid can be exposed from the first insulating layer.

[0029] After step S120 , the process proceeds to step S130 : forming a conductive structure on the main grid by an electroplating process.

[0030] Please also refer to Figure 2 and Figure 3Since at least part of the structure of the main grid 111 is not covered by the first insulating layer (not shown in the figure), the conductive structure 12 can be plated on the main grid 111 through the electroplating process. The conductive structure 12 is formed on one side of the main grid 111 along the thickness direction Z of the battery cell 11. The conductive structure 12 is fixed to the main grid 111 and electrically connected to the main grid 111 so that the conductive structure 12 collects, converges and outputs the current of the main grid 111. The area of ​​the hollow area of ​​the first insulating layer matches the area of ​​the conductive structure 12, and the area covered by the first insulating layer cannot form the conductive structure 12 under the insulating effect of the first insulating layer.

[0031] After step S130 , the process proceeds to step S140 : removing the first insulating layer.

[0032] Specifically, the first insulating layer can be removed using an acidic solution or an alkaline solution. After step S140, the cell has a fine grid, a main grid, and a conductive structure corresponding to the main grid.

[0033] After step S140, the process proceeds to step S150: electrically connecting the conductive structures of adjacent battery cells through connectors.

[0034] Please also refer to Figure 4 The connector 13 corresponds to the conductive structure 12 of the battery cell 11 one by one, and is fixedly connected to the conductive structure 12, and the connection method can be bonding, welding, etc., so as to achieve the fixation between two adjacent battery cells 11. At the same time, the connector 13 is a conductor, so that the two adjacent battery cells 11 are electrically connected through the connector 13, that is, the two adjacent battery cells 11 can form a battery string 10 through the connector 13.

[0035] In some embodiments, the connector 13 is a conductive adhesive. In step S140, the conductive adhesive can be applied between the conductive structures 12 of two adjacent battery cells 11, and then the conductive adhesive is cured so that the conductive adhesive is bonded between the conductive structures 12 of the two adjacent battery cells 11, thereby achieving electrical connection between the two battery cells 11.

[0036] In other embodiments, the connector 13 may be a conductive solder paste.

[0037] In other embodiments, the connector 13 is a metal strip, which includes a metal inner core and a coating disposed on the outer surface of the metal inner core. In step S140, the metal strip can be welded between the conductive structures 12 of two adjacent battery cells 11 to achieve electrical connection and fixation between the two battery cells 11, wherein the metal inner core can be made of metal materials such as copper bars and aluminum bars. The coating can be a tin coating, which protects the metal inner core and reduces the possibility of oxidation, corrosion and damage to the metal inner core.

[0038] In the embodiment of the present application, the conductive structure 12 collects, converges and transmits the current of the main grid 111. The conductive structures 12 of adjacent cells 11 are electrically connected through the connector 13. That is, the current is transmitted through the conductive structure 12 and the connector 13, and the adjacent cells 11 are fixed through the connector 13, so that there is no need to set a welding strip between the cells 11, that is, the connector 13 and the conductive structure 12 play the role of replacing the welding strip. The conductive structure 12 is formed on the main grid 111 through the electroplating process, so that the cell 11 does not need to be soldered in series, avoiding the problem of poor series return of the cell 11, improving the yield of the photovoltaic module and the preparation efficiency of the photovoltaic module, and reducing the loss of the cell 11. On the other hand, the electroplating process is easy to implement and has low cost. The electroplating process realizes the stable and reliable connection between the conductive structure 12 and the main grid 111, improves the stability and reliability of the photovoltaic module, and is conducive to simplifying the preparation process of the photovoltaic module and reducing the production cost of the photovoltaic module.

[0039] In some embodiments, the substrate has a first surface and a second surface along its thickness direction, and the first surface can be the front side of the substrate, that is, the surface that can be directly illuminated by sunlight. The second surface can be the back side of the substrate, that is, the surface that is not directly illuminated by sunlight. Both the first surface and the second surface can receive sunlight and convert light energy into electrical energy. The above-mentioned battery cell can be a back-contact solar cell, that is, the main grid and the fine grid of the battery cell are only arranged on the second surface of the substrate, so that the first surface is not blocked by the grid line, the light receiving area of ​​the first surface is increased, the light-shielding current loss is reduced, and the maximum utilization of the incident photons is achieved. Specifically, when preparing a photovoltaic module, a main grid and a fine grid can be formed on the second surface of the substrate. In the subsequent electroplating process, the second surface of the battery cell can be placed in the electroplating solution to form a conductive structure on the main grid, and then the conductive structures of two adjacent battery cells are connected by a connector to form a battery string.

[0040] like Figure 4 As shown, when the cell 11 is the above-mentioned back-contact solar cell, the connector 13 can be connected between the conductive structures 12 of two adjacent cells 11 along the width direction Y of the cell 11. Along the thickness direction Z of the cell 11, the cross-sectional area of ​​the connector 13 is the same as the cross-sectional area of ​​the conductive structure 12, which facilitates the connection between the connector 13 and the conductive structure 12 and improves the reliability of the connection between the connector 13 and the conductive structure 12.

[0041] In other embodiments, the first surface and the second surface of the cell are both provided with a main grid and a fine grid. When preparing a photovoltaic module, the main grid and the fine grid can be formed on the first surface and the second surface of the substrate. In the subsequent electroplating process, the first surface and the second surface of the cell can be placed in the electroplating solution to form a conductive structure on the main grid of the first surface and the main grid of the second surface, and then the conductive structures of two adjacent cells are connected by a connector to form a battery string. One end of the connector is connected to the conductive structure of the first surface of one cell, and the other end of the connector is connected to the conductive structure of the second surface of another cell.

[0042] like Figure 2 and Figure 3 As shown, in a possible implementation, the step of forming the conductive structure 12 on the main gate 111 by an electroplating process includes: the conductive structure 12 has a width greater than or equal to the width of the main gate 111 .

[0043] The width W1 of the conductive structure 12 can satisfy: 0.35mm≤W1≤2.05mm. For example, W can be 0.35mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm or 2.05mm. Of course, it can also be other values ​​within the above range. By limiting the width of the conductive structure 12, the shading area of ​​the conductive structure 12 can be reduced while ensuring the stability of the connection between the conductive structure 12 and the main grid 111, thereby improving the photoelectric conversion efficiency of the photovoltaic module.

[0044] In a specific embodiment, the width of the conductive structure 12 is equal to the width of the main grid 111, and the length of the conductive structure 12 is equal to the length of the main grid 111. Along the thickness direction Z of the battery cell 11, the projection area of ​​the conductive structure 12 is the same as the projection area of ​​the main grid 111, and the projection of the conductive structure 12 coincides with the projection of the main grid 111, so that the conductive structure 12 covers the main grid 111, thereby improving the stability of the connection between the conductive structure 12 and the main grid 111 and ensuring the stability of current transmission. At the same time, the shading area of ​​the conductive structure 12 is reduced, which is beneficial to improving the photoelectric conversion efficiency of the photovoltaic module.

[0045] In another specific embodiment, the width of the conductive structure 12 is greater than the width of the main grid 111, and the length of the conductive structure 12 is greater than the length of the main grid 111. Along the thickness direction Z of the battery cell 11, the projection area of ​​the conductive structure 12 is greater than the projection area of ​​the main grid 111, and the projection of the main grid 111 falls within the projection of the conductive structure 12, so that the conductive structure 12 completely covers the main grid 111. By increasing the size of the conductive structure 12, the stability of the connection between the conductive structure 12 and the main grid 111 is improved, the stability of current transmission is ensured, and it is also beneficial to reduce the loss during current transmission, thereby facilitating the improvement of the reliability of the photovoltaic module.

[0046] In some other embodiments, the length of the conductive structure 12 may be smaller than the length of the main gate 111 .

[0047] The area of ​​the hollow region of the first insulating layer can be designed according to the area of ​​the conductive structure, that is, the area of ​​the hollow region can be greater than, equal to or equal to the area of ​​the main grid, so as to form a conductive structure of corresponding size on the main grid.

[0048] In a possible implementation manner, the step of forming a conductive structure on the main grid by an electroplating process includes: forming a conductive structure with a thickness D1 satisfying: 0.05 mm≤D1≤0.3 mm.

[0049] The thickness D1 of the conductive structure can be 0.02mm, 0.04mm, 0.05mm, 0.06mm, 0.08mm, 0.09mm, 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm, 0.2mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, 0.3mm, 0.32mm, 0.34mm or 0.35mm. In some embodiments, the thickness D1 of the conductive structure satisfies: 0.05mm≤D1≤0.3mm. By limiting the thickness of the conductive structure, the stability of the conductive structure itself is improved, the possibility of the conductive structure being broken is reduced, and it is also beneficial to reduce the shading area of ​​the conductive structure and improve the photoelectric conversion efficiency of the photovoltaic module.

[0050] like Figure 4 As shown, in some embodiments, the length L of the connector 13 satisfies: 1.5 mm ≤ L ≤ 10.5 mm. For example, L can be 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm or 10.5 mm. By limiting the length L of the connector 13, it is beneficial to improve the stability of the connector 13 structure itself and reduce the loss of current transmission.

[0051] The width W2 of the connector 13 satisfies 0.35 mm ≤ W2 ≤ 2.05 mm. For example, W2 may be 0.35 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm or 2.05 mm. Of course, it may be other values ​​within the above range. In some embodiments, the width of the connector 13 may be the same as the width of the conductive structure 12 to improve the stability of the connection between the connector 13 and the conductive structure 12.

[0052] The thickness D2 of the connector 13 satisfies: 0.05 mm ≤ D2 ≤ 0.3 mm. For example, D2 may be 0.05 mm, 0.06 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.12 mm, 0.14 mm, 0.16 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.24 mm, 0.26 mm, 0.28 mm, 0.3 mm, and may be other values ​​within the above range. In some embodiments, the thickness of the connector 13 may be the same as the thickness of the conductive structure 12 to improve the stability of the connection between the connector 13 and the conductive structure 12.

[0053] In a possible implementation, before the step of electrically connecting the conductive structures of adjacent cells via a connector, the method for preparing a photovoltaic module includes: Step S160: forming a protection layer on the conductive structure through an electroplating process.

[0054] The protective layer protects the conductive structure, reduces the possibility of oxidation or corrosion of the conductive structure, and reduces the possibility of wear or breakage thereof, thereby improving the reliability of the conductive structure.

[0055] In a possible implementation, the step of forming a conductive structure on the main grid by an electroplating process includes: electroplating copper on the main grid so that the conductive structure is a copper strip.

[0056] Specifically, when preparing the conductive structure, the electroplating solution used may be copper sulfate to form copper strips on the main grid. Metallic copper has good electrical conductivity and low cost, which is beneficial for improving the performance of photovoltaic modules while reducing the production cost of photovoltaic modules.

[0057] The step of forming a protective layer on the conductive structure by an electroplating process includes: electroplating tin on the conductive structure so that the protective layer is a tin layer.

[0058] Specifically, when preparing the protective layer, the electroplating solution used may be stannous sulfate to form a tin layer on the surface of the conductive structure. The tin layer can reliably protect the conductive structure to improve the stability and reliability of the conductive structure.

[0059] In a possible implementation, a method for preparing a photovoltaic module includes: forming a main grid and a fine grid on a substrate by an electroplating process.

[0060] Specifically, when preparing the main grid and the fine grid, the electroplating solution used can be copper sulfate to form a copper main grid and a copper fine grid on the substrate. Compared with the solution of using metal slurry to prepare the main grid and the fine grid, preparing the main grid and the fine grid through the electroplating process reduces the use of metal slurry, especially the use of silver slurry, which is conducive to reducing the production cost of photovoltaic modules. At the same time, metallic copper has good electrical conductivity. The use of copper main grid and copper fine grid is conducive to reducing the loss of current transmission and improving the photoelectric conversion efficiency of photovoltaic modules.

[0061] The following describes in detail the process of forming the main gate and the fine gate on the substrate through the electroplating process.

[0062] In a possible implementation, the substrate of the cell includes a target area and a non-target area, and the method for preparing a photovoltaic module includes: Step S111: opening a slot in the target area.

[0063] The target area can be understood as the area where the grid lines are set on the cell. In step S11, a laser can be used to open a groove on the substrate, and the groove extends along the thickness direction of the cell. The size of the groove can be adjusted according to the size of the main grid and the fine grid. By opening the groove, it is convenient for the main grid and the fine grid formed subsequently to form a good electrical connection with the substrate, so as to achieve normal and stable operation of the photovoltaic module.

[0064] After step S111 , the process proceeds to step S112 : forming a seed layer in the target area and the non-target area.

[0065] The seed layer may include an aluminum silicon layer (AlSi), a titanium tungsten layer (TiW) and a copper layer (Cu), and the seed layer may be deposited on the substrate by physical vapor deposition. The seed layer is provided to facilitate the subsequent electroplating process and improve the adhesion between the main grid and the fine grid and the cell substrate.

[0066] After step S112, the process proceeds to step S113: providing a second insulating layer in the non-target area.

[0067] The non-target area can be understood as an area on the cell where no grid lines are provided. The second insulating layer can be formed on the non-target area by overspraying or printing. The second insulating layer can be a film layer with insulating properties such as an insulating ink layer and an insulating adhesive layer.

[0068] After step S113, the process proceeds to step S114: electroplating is performed in the target area to form a main grid and a fine grid in the target area. The electroplating solution may be copper sulfate to form a copper main grid and a copper fine grid on the substrate.

[0069] After step S114 , the process proceeds to step S115 : removing the second insulating layer and the seed layer that is not in contact with the main gate and the fine gate.

[0070] In some embodiments, after step S112 and before step S113, the battery cell may be subjected to an annealing treatment to passivate the battery cell.

[0071] In some embodiments, before step S111, the cell may be subjected to annealing treatment and light injection treatment to optimize the electrical performance of the cell, thereby improving the photoelectric conversion efficiency of the photovoltaic module.

[0072] During the preparation process of the photovoltaic module of the embodiment of the present application, the main grid, the fine grid and the conductive structure on the main grid of the battery cell can be prepared by electroplating process, and the specific method steps are as follows: Step S201: pre-processing the cell, including surface cleaning, annealing, light injection and other steps.

[0073] Step S202: opening a groove in a target area of ​​the battery cell. Step S202 is the same as step S11 and will not be described again here.

[0074] Step S203: forming a seed layer in the target area and the non-target area. Step S203 is the same as step S112 and will not be described again here.

[0075] Step S204: performing annealing treatment on the battery cell to passivate the battery cell.

[0076] Step S205: a second insulating layer is provided in the non-target area. Step S205 is the same as step S113 and will not be described again here.

[0077] Step S206: electroplating is performed in the target area to form a main gate and a fine gate in the target area. Step S206 is the same as step S114 and will not be described again here.

[0078] Step S207: a patterned first insulating layer is provided on the cell, so that at least a part of the structure of the main grid is exposed from the first insulating layer. Step S207 is the same as step 120, and will not be described again here.

[0079] Step S208: forming a conductive structure on the main grid by electroplating. Step S208 is the same as step S130 and will not be described again.

[0080] Step S209: forming a protective layer on the conductive structure, the main grid and the fine grid by electroplating. Specifically, the electroplating solution may be stannous sulfate to form a tin layer on the surface of the conductive structure, the main grid and the fine grid. Before preparing the protective layer, the first insulating layer covering the fine grid is removed to electroplate the protective layer on the surface of the fine grid, while the areas outside the conductive structure, the main grid and the fine grid are not affected by the electroplating due to the action of the insulating layers.

[0081] Step S210: removing the first insulating layer, the second insulating layer, and the seed layer that is not in contact with the main gate and the fine gate.

[0082] In some embodiments, when preparing photovoltaic modules, the main grid, fine grid and conductive structure are all prepared through an electroplating process, and the electroplating solution used to form the main grid and the fine grid and the electroplating solution used to form the conductive structure are copper sulfate. That is to say, the main grid, the fine grid and the conductive structure are all metallic copper, which is beneficial to improving the stability of the connection between the main grid and the conductive structure.

[0083] The embodiment of the present application provides a photovoltaic module, which is prepared by the above-mentioned photovoltaic module preparation method. The photovoltaic module includes a cover plate, an encapsulation layer and a battery string, wherein the encapsulation layer is located between the cover plate and the battery string, and the cover plate is connected to the battery string through the encapsulation layer.

[0084] like Figure 5 As shown, the cover plate may include a first cover plate 20 and a second cover plate 30, the first cover plate 20 may be located on the upper layer of the photovoltaic module 100, and the second cover plate 30 may be located on the lower layer of the photovoltaic module 100. The encapsulation layer includes a first encapsulation layer 40 and a second encapsulation layer 50, the first encapsulation layer 40 may be located between the first cover plate 20 and the battery string 10, and the second encapsulation layer 50 may be located between the second cover plate 30 and the battery string 10.

[0085] The first cover plate 20, the first encapsulation layer 40, the battery string 10, the second encapsulation layer 50 and the second cover plate 30 can be arranged along the thickness direction Z of the photovoltaic module 100 and laminated together. Among them, the first cover plate 20 can be a glass cover plate, and the first cover plate 20 has a high light transmittance. The first encapsulation layer 40 bonds the first cover plate 20 and the battery string 10 together to play a role in encapsulation and protection of the battery string 10. The material of the first encapsulation layer 40 can be one or more of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE) and polyvinyl butyral (PVB). The second encapsulation layer 50 connects the battery layer and the second cover plate 30 together, which also plays a role in encapsulation and protection of the battery string 10. The material of the second encapsulation layer 50 can be one or more of the above-mentioned EVA, POE, and PVB. The material of the second cover plate 30 can be glass, or the second cover plate 30 can also be composed of multiple polymer film layers.

[0086] The types of cells in the cell string 10 include, but are not limited to, Passivated Emitter Rear Cell (PERC), Tunnel Oxide Passivated Contact (TOPCon), Heterojunction with Intrinsic Thin-film (HJT), Interdigitated Back Contact (IBC), perovskite cells, etc.

[0087] For PERC cells, along the thickness direction, PERC cells include the front surface metal silver electrode, the front surface silicon nitride passivation layer, the phosphorus layer emitter, the P-type base silicon layer, the local aluminum back field, the metal aluminum back electrode, and the back passivation layer (Al2O3 / SiNx). PERC cells use a passivation film to passivate the back, replacing the full aluminum back field, enhancing the internal back reflection of light in the silicon base, reducing the recombination rate on the back, and increasing the efficiency of the cell by 0.5%-1%.

[0088] For TOPCon cells, along the thickness direction, TOPCon cells include metal silver electrodes, front surface silicon nitride passivation layers, boron-doped emitters, N-type base silicon layers, diffused doping layers, ultra-thin silicon oxide, doped polysilicon, silicon nitride, and metal silver electrodes. The back of the cell is composed of an ultra-thin silicon oxide layer (1nm~2nm) and a phosphorus-doped microcrystalline amorphous mixed Si film, which together form a passivation contact structure. This structure can block the recombination of minority carrier holes and increase the open circuit voltage and short circuit current of the cell. The ultra-thin oxide layer allows majority electrons to tunnel into the polysilicon layer while blocking the recombination of minority carrier holes. The good passivation effect of ultra-thin silicon oxide and heavily doped silicon film causes the energy band on the silicon wafer surface to bend, thereby forming a field passivation effect, greatly increasing the probability of electron tunneling, and reducing the contact resistance, which increases the open circuit voltage and short circuit current of the cell, thereby improving the cell conversion efficiency.

[0089] For HJT cells, along the thickness direction, the HJT cells include a front low-temperature silver electrode, a front conductive film, an N-type amorphous silicon film, an intrinsic amorphous silicon film, an N-type base silicon layer, an intrinsic amorphous silicon film, a P-type amorphous silicon film, a back conductive film, and a back low-temperature silver electrode.

[0090] For IBC cells, along the thickness direction, IBC cells include silicon nitride anti-layer, N+ front surface field, N-type base silicon layer, P+ emitter, N+ back field, aluminum oxide passivation layer, silicon nitride anti-reflection layer, and metal silver electrode. IBC cells use ion implantation technology to obtain P and N regions with good uniformity and precisely controllable junction depth. There is no grid line blocking on the front of the cell, which can eliminate the shading current loss of the metal electrode and achieve the maximum utilization of incident photons. The short-circuit current can be increased by about 7% compared with conventional solar cells; due to the back contact structure, there is no need to consider the grid line blocking problem, and the grid line ratio can be appropriately widened, thereby reducing the series resistance and having a high fill factor; the surface passivation and surface light trapping structure can be optimized to obtain a lower front surface recombination rate and surface reflection.

[0091] For perovskite cells, along the thickness direction, the perovskite cell includes substrate material, conductive film, electron transport layer (titanium dioxide), perovskite absorption layer (hole transport layer), and metal cathode. Perovskite materials have 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 electrode with low loss, so they can generate higher photoelectric voltage and current, making perovskite show higher photoelectric conversion efficiency.

[0092] Combination Figures 2 to 4 As shown, since the photovoltaic module is prepared by the above-mentioned method for preparing the photovoltaic module, the cell 11 has a main grid 111 and a fine grid 112. The main grid 111 is connected to a conductive structure 12 on one side along the thickness direction Z of the cell 11, and the conductive structures 12 of adjacent cells 11 are electrically connected through a connector 13. Among them, along the thickness direction Z of the cell 11, the projection of the main grid 111 can be located within the projection of the corresponding conductive structure 12, and the thickness D of the conductive structure 12 can satisfy: 0.05mm≤D≤0.3mm. The width W of the conductive structure 12 can satisfy: 0.35mm≤W≤2.05mm. The design of the thickness of the conductive structure 12 and the effect of the width design have been introduced above and will not be repeated here.

[0093] The cell 11 may be a back-contact solar cell, and the connector 13 may be connected between the conductive structures 12 of two adjacent cell cells 11 along the width direction Y of the cell 11 .

[0094] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a photovoltaic module, characterized in that: The photovoltaic module includes a cell, and the preparation method of the photovoltaic module includes: forming a main grid and a fine grid on the substrate of the cell; Disposing a patterned first insulating layer on the cell sheet so that at least a portion of the structure of the main grid is exposed from the first insulating layer; forming a conductive structure on the main grid by an electroplating process; removing the first insulating layer; The conductive structures of adjacent battery cells are electrically connected via connectors.

2. The method for preparing a photovoltaic module according to claim 1, characterized in that: The step of forming a conductive structure on the main grid by electroplating process comprises: A conductive structure having a width greater than or equal to the width of the main gate is formed.

3. The method for preparing a photovoltaic module according to claim 2, characterized in that: The step of forming a conductive structure on the main grid by electroplating process comprises: A conductive structure is formed with a thickness D1 satisfying: 0.05 mm ≤ D1 ≤ 0.3 mm.

4. The method for preparing a photovoltaic module according to claim 1, characterized in that: Before the step of electrically connecting the conductive structures of the adjacent cells via a connector, the method for preparing the photovoltaic module includes: A protection layer is formed on the conductive structure by an electroplating process.

5. The method for preparing a photovoltaic module according to claim 4, characterized in that: The step of forming a conductive structure on the main grid by electroplating process comprises: Electroplating copper on the main grid so that the conductive structure is a copper strip; The step of forming a protective layer on the conductive structure by an electroplating process comprises: Tin is electroplated on the conductive structure so that the protective layer is a tin layer.

6. The method for preparing a photovoltaic module according to any one of claims 1 to 5, characterized in that: The method for preparing the photovoltaic module comprises: The main gate and the fine gate are formed on the substrate by an electroplating process.

7. The method for preparing a photovoltaic module according to claim 6, characterized in that: The substrate of the cell comprises a target area and a non-target area, and the method for preparing the photovoltaic module comprises: Opening a slot in the target area; forming a seed layer in the target area and the non-target area; Disposing a second insulating layer in the non-target area; Performing electroplating in the target area to form the main grid and the fine grid in the target area; The second insulating layer and the seed layer not in contact with the main gate and the fine gate are removed.

8. A photovoltaic module, characterized in that: The photovoltaic module is prepared by the method for preparing a photovoltaic module according to any one of claims 1 to 7.

9. The photovoltaic module according to claim 8, characterized in that: The photovoltaic module comprises a cover plate, an encapsulation layer and a battery string, wherein the encapsulation layer is located between the cover plate and the battery string, and the cover plate is connected to the battery string through the encapsulation layer; The battery string includes a plurality of battery cells, each of which has a main grid and a fine grid. One side of the main grid along the thickness direction of the battery cell is connected with a conductive structure, and the conductive structures of adjacent battery cells are electrically connected via a connector.

10. The photovoltaic module according to claim 9, characterized in that: Along the thickness direction of the battery cell, the projection of the main grid is located within the projection of the corresponding conductive structure; The thickness D of the conductive structure satisfies: 0.05 mm≤D≤0.3 mm.

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