Connection structure, battery string and photovoltaic module

Abstract

This utility model discloses a connection structure, a battery string, and a photovoltaic module, relating to the field of photovoltaic module technology. The connection structure includes: a carrier adhesive film covering the back of multiple BC battery cells; solder ribbons spaced apart on the side of the carrier adhesive film that contacts the back of the BC battery cells; and a conductive metal paste disposed on the side of the solder ribbons that does not contact the carrier adhesive film, used to connect the solder ribbons to the BC battery cells. This embodiment simplifies the BC battery cell structure and reduces the possibility of poor contact or detachment of the solder ribbons from the electrodes.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic module technology, and in particular to a connection structure, a battery string and a photovoltaic module. Background Technology

[0002] In the field of solar cells, placing both the positive and negative electrodes on the back side of the cell can reduce the shading of the light-receiving surface by the electrodes, increase the amount of sunlight reaching the light-receiving surface, and thus improve the performance of the solar cell.

[0003] Multiple back-contact solar cells are mainly connected to the electrodes printed on the back of the cells via solder ribbons to form a cell string, thus achieving interconnection between the cells. However, problems such as poor contact and detachment of the solder ribbons from the electrode grid lines on the back of the cells are prone to occur, reducing the yield and lifespan of the cell string and photovoltaic module. Utility Model Content

[0004] In view of this, the present invention provides a connection structure, a battery string, and a photovoltaic module, which can simplify the structure of the BC battery cell, reduce the possibility of poor contact and detachment between the solder ribbon and the electrode, maintain the integrity of the photovoltaic module structure, effectively extend the service life of the photovoltaic module, and enhance the performance of the photovoltaic module.

[0005] To achieve the above objectives, according to one aspect of the present invention, a connection structure is provided for connecting multiple BC battery cells in series, comprising: a carrier adhesive film for covering the back side of the multiple BC battery cells;

[0006] The welding strips, multiple of which are spaced apart, are disposed on the side of the carrier adhesive film that contacts the back of the BC battery cell;

[0007] A conductive metal paste is disposed on the side of the solder ribbon that is not in contact with the carrier adhesive film, and the conductive metal paste is used to connect the solder ribbon to the BC battery cell.

[0008] Optionally, a first groove arranged at intervals is provided on one side of the carrier adhesive film, and the welding strip is embedded in the first groove.

[0009] Optionally, a second groove is provided on one side of the welding strip, and the metal conductive paste is filled in the second groove.

[0010] Optionally, the first groove is a V-shaped groove or an arc-shaped groove whose cross-section gradually decreases from top to bottom, and the welding strip matches the first groove.

[0011] Optionally, the metal conductive paste is a low-temperature curing conductive paste, which can be tightly connected to both the BC battery cell and the solder ribbon under lamination temperature conditions.

[0012] To achieve the above objectives, according to another aspect of the present invention, a battery string is provided, comprising: a plurality of BC battery cells and the connection structure described in any one of the embodiments of the present invention, wherein,

[0013] The back side of the BC battery cell includes: alternating P-type regions and N-type regions, a first conductive structure disposed in the P-type region and a second conductive structure disposed in the N-type region, wherein the first conductive structure and the second conductive structure are electrically isolated.

[0014] The carrier adhesive film of the connection structure covers the back of the plurality of BC battery cells;

[0015] For each pair of adjacent BC battery cells, the first conductive structure of one BC battery cell and the second conductive structure of the other BC battery cell are connected to a solder strip in the carrier adhesive film through a metal conductive paste on the solder strip, so as to connect multiple BC battery cells in series.

[0016] Optionally, the extension direction of the weld strip is consistent with the extension direction of the P-type region and the N-type region.

[0017] or,

[0018] The extension direction of the aforementioned solder strip is perpendicular to the extension direction of the aforementioned P-type region and the aforementioned N-type region.

[0019] Optionally, the edge of the carrier adhesive film extends beyond the edge of the BC battery cell.

[0020] Optionally, the contact area between each of the aforementioned solder strips and the aforementioned BC battery cell is smaller than the area of ​​the aforementioned P-type region or the aforementioned N-type region corresponding to the aforementioned solder strip.

[0021] Optionally, the first conductive structure is a first transparent conductive layer, the second conductive structure is a second transparent conductive layer, and the metal conductive paste on the solder strip is directly connected to its corresponding first transparent conductive layer or second transparent conductive layer;

[0022] or,

[0023] The first conductive structure includes a first transparent conductive layer and a first electrode disposed on the first transparent conductive layer. The second conductive structure includes a second transparent conductive layer and a second electrode disposed on the second transparent conductive layer. The metal conductive paste on the solder strip is directly connected to its corresponding first electrode or second electrode.

[0024] Optionally, the first conductive structure is a first electrode, the second conductive structure is a second electrode, and the metal conductive paste on the solder strip is directly connected to its corresponding first electrode or second electrode.

[0025] Optionally, the back side of the BC cell further includes a second tunneling oxide layer disposed in the P-type region and the N-type region; the second tunneling oxide layer is in contact with the silicon substrate;

[0026] or,

[0027] The back side of the BC battery cell also includes an intrinsic silicon hydrogenation layer disposed in the P-type region and a first tunneling oxide layer disposed in the N-type region, wherein the intrinsic silicon hydrogenation layer and the first tunneling oxide layer are respectively in contact with the silicon substrate.

[0028] Optionally, the back side of the BC battery cell further includes a second tunneling oxide layer disposed in the P-type region and the N-type region, the second tunneling oxide layer being in contact with the silicon substrate; a first passivation antireflection layer disposed inside the first conductive structure in the P-type region; and a second passivation antireflection layer disposed inside the second conductive structure in the N-type region.

[0029] To achieve the above objectives, according to another aspect of the present invention, a photovoltaic module is provided, comprising: a cover plate, an upper encapsulating film, a back sheet, and at least one battery string according to the present invention.

[0030] The aforementioned encapsulating film is disposed between the aforementioned cover plate and at least one of the aforementioned battery strings;

[0031] At least one of the aforementioned battery strings is disposed between the aforementioned upper encapsulation film and the aforementioned backplate;

[0032] The connection structure of the aforementioned battery string faces one side of the aforementioned back plate.

[0033] One embodiment of the above-described utility model has the following advantages or beneficial effects: By setting solder ribbons spaced apart on one side of the carrier film in the connection structure and setting a metal conductive paste on the outside of the solder ribbons, metal electrodes can be omitted in the BC cell, simplifying the structure of the BC cell. Furthermore, by setting the metal conductive paste on the outside of the solder ribbons, the solder ribbons and the metal conductive paste are in close contact. In the photovoltaic module prepared using this cell string, there is a strong mechanical connection between the electrodes and the solder ribbons, reducing the possibility of poor contact or detachment between the solder ribbons and electrodes. This maintains the integrity of the photovoltaic module structure, effectively extends the service life of the photovoltaic module, and enhances the performance of the photovoltaic module.

[0034] The further effects of the aforementioned unconventional alternative methods will be explained below in conjunction with specific implementation methods. Attached Figure Description

[0035] The accompanying drawings are provided to better understand this utility model and do not constitute an undue limitation thereof. Wherein:

[0036] Figure 1 This is a longitudinal cross-sectional schematic diagram of the connection structure according to an embodiment of the present utility model;

[0037] Figure 2 This is a schematic diagram of the connection structure facing the BC battery cell according to an embodiment of the present invention;

[0038] Figure 3 This is a longitudinal cross-sectional schematic diagram of a BC battery cell according to an embodiment of the present utility model;

[0039] Figure 4 This is a longitudinal cross-sectional schematic diagram of the battery string according to the first embodiment of the present invention;

[0040] Figure 5 This is a schematic diagram of the longitudinal section of the battery string according to the second embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of a whole battery cell being cut into BC battery cells according to an embodiment of the present invention;

[0042] Figure 7 This is a schematic diagram of a structure according to an embodiment of the present invention, showing that the extension direction of the solder strip is consistent with the extension directions of the P-type region and the N-type region.

[0043] Figure 8 This is a schematic diagram of a structure in which the extension direction of the solder strip according to an embodiment of the present invention is perpendicular to the extension direction of the P-type region and the N-type region;

[0044] Figure 9 According to the embodiments of this utility model Figure 8 A schematic cross-sectional view along the middle AA section;

[0045] Figure 10 This is a schematic diagram of the structure of a photovoltaic module according to an embodiment of the present utility model.

[0046] Figure label:

[0047] 1-Battery string; a-Complete battery cell; 11-BC battery cell; 111-P-type region; 1111-First transparent conductive layer; 1112-P-type doped polycrystalline silicon layer; 1113-Intrinsic hydrogenated silicon layer; 1114-Second tunneling oxide layer; 112-N-type region; 1121-Second transparent conductive layer; 1122-N-type doped polycrystalline silicon layer; 1123-First tunneling oxide layer; 1124-First insulating layer; 113-Spacer region; 114-Silicon substrate; 12-Connection structure; 121-Carrier adhesive film; 1211-First groove; 122-Solder ribbon; 1221-Second groove; 123-Metallic conductive paste; 2-Cover plate; 3-Upper encapsulation film; 4-Back plate. Detailed Implementation

[0048] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of the present invention, including various details to aid understanding. These embodiments should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0049] It should be noted that, in this embodiment of the present invention, the back side of the BC battery cell 11 refers to the side of the BC battery cell 11 that is away from sunlight when it is working, and correspondingly, the front side of the BC battery cell 11 refers to the side of the BC battery cell 11 that faces sunlight when it is working. In this embodiment of the present invention, the outer side of the solder ribbon 122 refers to the side of the solder ribbon 122 that is away from the carrier adhesive film 121.

[0050] The inner side of the first conductive structure in this embodiment refers to the side of the first conductive structure close to the silicon substrate 114; the inner side of the second conductive structure in this embodiment refers to the side of the second conductive structure close to the silicon substrate 114.

[0051] In this embodiment of the invention, the outer side of the P-type doped polysilicon layer and the outer side of the N-type doped polysilicon layer both represent the side of the corresponding functional layer away from the silicon substrate 114.

[0052] It should be noted that, where there is no conflict, the embodiments of this utility model and the technical features in the embodiments can be combined with each other.

[0053] like Figure 1 As shown, this embodiment of the invention provides a connection structure 12 applied to a battery string 1 for connecting multiple BC battery cells 11 in series. The connection structure 12 includes: a carrier adhesive film 121, a solder ribbon 122, and a metal conductive paste 123.

[0054] The aforementioned carrier film 121 is used to cover the back of the plurality of BC battery cells 11 in the aforementioned battery string 1.

[0055] Multiple welding strips 122 are spaced apart on the side of the carrier film 121 that contacts the back of the BC battery cell 11. The carrier film 121 may include one or more of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), and expandable polyethylene (EPE).

[0056] The conductive metal paste 123 is disposed on the side of the solder ribbon 122 that is not in contact with the carrier adhesive film 121, and the conductive metal paste 123 is used to connect the solder ribbon 122 to the BC battery cell 11.

[0057] like Figure 2 As shown, several solder strips 122 are arranged alternately on one side of the carrier adhesive film 121.

[0058] Specifically, the connection structure 12 of this utility model embodiment is not only applicable to, as in, Figure 3 The BC battery cell 11 shown is also applicable to BC battery cells with metal electrodes.

[0059] As an example, when connection structure 12 and Figure 3 When the BC battery cells 11 shown are used in conjunction, the metal conductive paste 123 in the connection structure 12 can directly contact the first transparent conductive layer 1111 and the second transparent conductive layer 1121 in the BC battery cell 11, so that the metal conductive paste 123 is electrically connected to the first transparent conductive layer 1111 and the second transparent conductive layer 1121. Specifically, for each pair of adjacent BC battery cells 11 in the battery string 1, the first transparent conductive layer 1111 of one BC battery cell 11 and the second transparent conductive layer 1121 of the other BC battery cell 11 are connected to a solder strip 122 in the carrier adhesive film 121 through the metal conductive paste 123 on the solder strip 122, so as to connect multiple BC battery cells 11 in series.

[0060] When the connection structure 12 is used in conjunction with a BC battery cell with metal electrodes, the metal conductive paste 123 in the connection structure 12 can directly contact the metal electrodes of the BC battery cell with metal electrodes, so that the metal conductive paste 123 is electrically connected to the metal electrodes.

[0061] It should be noted that the BC battery cell with metal electrodes may or may not have a first transparent conductive layer 1111 and a second transparent conductive layer 1121. For example, if the first transparent conductive layer 1111 and the second transparent conductive layer 1121 are not provided, a first passivation anti-reflection layer may be provided on the outside of the P-type doped polysilicon layer, and a second passivation anti-reflection layer may be provided on the outside of the N-type doped polysilicon layer.

[0062] In one alternative embodiment, such as Figure 1 As shown, a first groove 1211 is provided on one side of the aforementioned carrier adhesive film 121, arranged at intervals, and the aforementioned solder strip 122 is embedded in the aforementioned first groove 1211. A plurality of first grooves 1211 are arranged alternately, thereby causing the solder strip 122 disposed in the first groove 1211 to be arranged alternately.

[0063] Furthermore, the upper surface of the aforementioned solder ribbon 122 may protrude from the first groove 1211, that is, be higher than the surface of the carrier adhesive film 121 on which the solder ribbon 122 is provided, so as to form a strong electrical connection between the solder ribbon 122 and the BC cell 11 when using the cell string 1 to prepare a photovoltaic module.

[0064] In addition, the upper surface of the solder ribbon 122 can be lower than the surface of the carrier adhesive film 121 where the solder ribbon 122 is provided or flush with the surface of the carrier adhesive film 121 where the solder ribbon 122 is provided, so that the thickness of the solder ribbon 122 contained in the first groove 1211 does not need to be considered, and the solder ribbon 122 can be provided in a variety of ways.

[0065] Optionally, the first groove 1211 can be a V-shaped groove or an arc-shaped groove with a cross-section that gradually decreases from top to bottom, but is not limited to these. It is understood that the V-shaped groove or arc-shaped groove can regulate the propagation and reflection of sunlight, as can be seen from... Figure 4 The incident light rays that hit the first groove 1211 can be reflected by the side wall of the first groove 1211 to the back of the BC battery cell 11, thereby increasing the amount of sunlight reflected to the back of the BC battery cell 11 and improving the photoelectric conversion efficiency of the BC battery cell 11.

[0066] Furthermore, the aforementioned solder strip 122 is matched with the first groove 1211. Specifically, the shape of the solder strip 122 disposed in the first groove 1211 can match the shape of the first groove 1211, so as to limit the solder strip 122 by the first groove 1211 and reduce the probability of the solder strip 122 shifting during the battery string 1 preparation process.

[0067] Furthermore, the solder ribbon 122 and the carrier film 121 can be fixedly connected or detachably connected. When the solder ribbon 122 is fixed within the first groove 1211 of the carrier film 121, the problem of solder ribbon 122 shifting during the manufacturing process can be solved. When the solder ribbon 122 and the carrier film 121 are detachably connected, it is convenient to replace the solder ribbon 122 in the carrier film 121. If the solder ribbon 122 has a problem, it can be replaced between the manufacturing of photovoltaic modules, which can effectively improve the yield of the cell string 1.

[0068] In one alternative embodiment, as follows Figure 1 As shown, a second groove 1221 is provided on one side of the solder strip 122; the conductive metal paste 123 is filled in the second groove 1221. Each solder strip 122 has a second groove 1221 for dispensing the conductive metal paste 123 on the side away from the carrier film. The shape of the second groove 1221 can be U-shaped, but is not limited to this.

[0069] The aforementioned conductive metal paste 123 includes, but is not limited to, silver paste, silver-aluminum paste, copper paste, or silver-coated copper paste. It is understood that the conductive metal paste 123 in different second grooves 1221 of the same connection structure 12 can be made of the same material or different materials. Generally, the same material can be selected to simplify the preparation process of the battery string 1.

[0070] Optionally, the metal conductive paste 123 can be a low-temperature curing conductive paste, which allows the metal conductive paste 123 to be cured under lamination temperature conditions, thereby achieving a tight connection between the metal conductive paste 123 and the BC battery cell 11 and the solder ribbon 122. This reduces the possibility of the connection structure 12 detaching from the BC battery cell 11, and also reduces the possibility of the metal conductive paste 123 detaching from the solder ribbon 122.

[0071] According to the connection structure 12 of this utility model embodiment, by providing a solder ribbon 122 on one side of the carrier film 121 and a metal conductive paste 123 on the outside of the solder ribbon 122, the solder ribbon 122 and the metal conductive paste 123 used to form the electrode are integrated into the carrier film 121 to form the connection structure 12. This can achieve a tight bond between the solder ribbon 122 and the metal conductive paste 123. After the electrode is formed by the metal conductive paste 123, there is a strong mechanical connection between the electrode and the solder ribbon 122, which reduces the possibility of poor contact and detachment between the electrode and the solder ribbon 122. This can maintain the integrity of the photovoltaic module structure, effectively extend the service life of the photovoltaic module, and enhance the performance of the photovoltaic module.

[0072] like Figure 3 , Figure 4 and Figure 5As shown, this embodiment of the present invention provides a battery string 1, including: a plurality of BC battery cells 11 and a connection structure 12 of the present invention. The back surface of the BC battery cells 11 includes: alternating P-type regions 111 and N-type regions 112, a first conductive structure disposed in the P-type regions 111, and a second conductive structure disposed in the N-type regions 112, wherein the first conductive structure and the second conductive structure are electrically isolated.

[0073] P-type region 111 refers to the region including P-type doped polysilicon layer 1112; N-type region 112 refers to the region including N-type doped polysilicon layer 1122. It is understood that P-type region 111 and N-type region 112 may also include other functional film layers.

[0074] The first conductive structure is disposed outside the P-type doped polysilicon layer 1112 of the P-type region 111, that is, on the side of the P-type doped polysilicon layer 1112 away from the silicon substrate 114. Similarly, the second conductive structure is disposed outside the N-type doped polysilicon layer 1122 of the N-type region 112, that is, on the side of the N-type doped polysilicon layer away from the silicon substrate 114.

[0075] There are multiple ways to configure the first conductive structure and the second conductive structure, which can include at least the following three examples:

[0076] The first example, such as Figure 3 As shown, the first conductive structure is a first transparent conductive layer 1111, the second conductive structure is a second transparent conductive layer 1121, and the metal conductive paste 123 on the solder ribbon 122 is directly connected to its corresponding first transparent conductive layer 1111 or second transparent conductive layer 1121.

[0077] In the second example, the first conductive structure is a first electrode, the second conductive structure is a second electrode, and the metal conductive paste 123 on the solder ribbon 122 is directly connected to its corresponding first electrode or second electrode.

[0078] In the third example, the first conductive structure includes a first transparent conductive layer 1111 and a first electrode disposed on the first transparent conductive layer 1111, and the second conductive structure includes a second transparent conductive layer 1121 and a second electrode disposed on the second transparent conductive layer 1121, wherein the metal conductive paste 123 on the solder ribbon 122 is directly connected to its corresponding first electrode or second electrode.

[0079] In an optional embodiment, the P-type region 111 and N-type region 112 on the back side of the BC battery cell 11 may further include other functional film layers, which may include, but are not limited to, the following three examples:

[0080] The first example, such as Figure 5 As shown, the back side of the BC battery cell 11 also includes a second tunneling oxide layer 1114 on which the P-type region 111 and the N-type region 112 are disposed; the second tunneling oxide layer 1114 is in contact with the silicon substrate 114. Specifically, in the P-type region 111, the second tunneling oxide layer 1114 is disposed between the P-type doped polycrystalline silicon layer 1112 and the silicon substrate 114; in the N-type region 112, the second tunneling oxide layer 1114 is disposed between the N-type doped polycrystalline silicon layer 1122 and the silicon substrate 114. The second tunneling oxide layers 1114 in the P-type region 111 and the N-type region 112 can be interconnected without obvious boundaries or gaps.

[0081] In a second example, the back side of the BC battery cell 11 further includes a second tunneling oxide layer 1114 disposed in the P-type region 111 and the N-type region 112, the second tunneling oxide layer 1114 being in contact with the silicon substrate 114; a first passivation antireflection layer disposed inside the first conductive structure in the P-type region 111; and a second passivation antireflection layer disposed inside the second conductive structure in the N-type region 112. The first passivation antireflection layer may be disposed between the P-type doped polysilicon layer 1112 in the P-type region 111 and the first conductive structure; the second passivation antireflection layer may be disposed between the N-type doped polysilicon layer 1122 in the N-type region 112 and the second conductive structure, where the first conductive structure is a first electrode and the second conductive structure is a second electrode.

[0082] In a third example, the back side of the BC battery cell 11 further includes an intrinsic silicon hydrogenation layer 1113 disposed in the P-type region 111 and a first tunneling oxide layer 1123 disposed in the N-type region 112. The intrinsic silicon hydrogenation layer 1113 and the first tunneling oxide layer 1123 can be in contact with the silicon substrate 114. Specifically, the intrinsic silicon hydrogenation layer 1113 can be disposed between the silicon substrate 114 and the P-type doped polycrystalline silicon layer 1112 in the P-type region 111, and in direct contact with the silicon substrate 114; the first tunneling oxide layer 1123 can be disposed between the silicon substrate 114 and the N-type doped polycrystalline silicon layer 1122 in the N-type region 112, and in direct contact with the silicon substrate 114.

[0083] Optionally, a spacer region 113 may be provided between the alternating P-type regions 111 and N-type regions 112 to separate the P-type regions 111 and N-type regions 112, thereby electrically isolating the first conductive structure from the second conductive structure and preventing leakage. The spacer region 113 is formed by removing a portion of the P-type doped polysilicon layer 1112 and the first conductive structure adjacent to the N-type region 112 in the P-type region 111, or by removing a portion of the N-type doped polysilicon layer 1122 and the second transparent polysilicon layer adjacent to the P-type region 111 in the N-type region 112. The spacer region 113 does not contain either the P-type doped polysilicon layer 1112 or the N-type doped polysilicon layer 1122.

[0084] Furthermore, when the P-type region 111 and the N-type region 112 include a second tunneling oxide layer 1114, a second tunneling oxide layer 1114 is also provided in the spacer region 113, so that the second tunneling oxide layers 1114 of the P-type region 111, the N-type region 112 and the spacer region 113 are interconnected and there is no clear boundary; when the P-type region 111 includes an intrinsic silicon hydride layer 1113 and the N-type region 112 includes a first tunneling oxide layer 1123, an intrinsic silicon hydride layer 1113 and a first tunneling oxide layer 1123 are also provided in the spacer region 113, so that the intrinsic silicon hydride layer 1113 and the first tunneling oxide layer 1123 are adjacent in the spacer region 113.

[0085] Alternatively, if the P-type region 111 and the N-type region 112 include a second tunneling oxide layer 1114, the second tunneling oxide layer 1114 may not be provided in the spacer region 113, so that the second tunneling oxide layers 1114 of the P-type region 111 and the N-type region 112 are disconnected in the spacer region 113; if the P-type region 111 includes an intrinsic silicon hydride layer 1113 and the N-type region 112 includes a first tunneling oxide layer 1123, neither the intrinsic silicon hydride layer 1113 of the P-type region 111 nor the first tunneling oxide layer 1123 of the N-type region 112 extends into the spacer region 113.

[0086] Optionally, the silicon substrate 114 of the BC cell 11 can be a P-type silicon substrate or an N-type silicon substrate.

[0087] The number of BC battery cells 11 in battery string 1 can be set according to actual conditions, such as the size and design voltage of the BC battery cells 11, and is not specifically limited here. Figure 6 As shown, the BC battery cell 11 can be obtained by cutting a whole battery cell a, and each BC battery cell 11 obtained after cutting has the same structure.

[0088] like Figure 4 and Figure 5As shown, the connection structure 12 includes a carrier adhesive film 121, solder ribbons 122, and a conductive metal paste 123. The carrier adhesive film 121 covers the back of the plurality of BC battery cells 11. Multiple solder ribbons 122 are spaced apart on the side of the carrier adhesive film 121 that contacts the back of the BC battery cells 11. The conductive metal paste 123 is disposed on the side of the solder ribbons 122 that does not contact the carrier adhesive film 121, and the conductive metal paste 123 connects the solder ribbons 122 to the BC battery cells 11.

[0089] The carrier film 121 may include one or more of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), and expandable polyethylene (EPE).

[0090] like Figure 2 As shown, a plurality of solder ribbons 122 are staggered on one side of the carrier film 121. For each solder ribbon 122, one end corresponds to the first conductive structure of one of the two adjacent BC battery cells 11, and the other end corresponds to the second conductive structure of the other of the two adjacent BC battery cells 11. Thus, for each pair of adjacent BC battery cells 11, the first conductive structure of one BC battery cell 11 and the second conductive structure of the other BC battery cell 11 are connected to one of the solder ribbons 122 in the carrier film 121 through the metal conductive paste 123 on the solder ribbon 122, so as to connect the plurality of BC battery cells 11 in series.

[0091] In one alternative embodiment, such as Figure 1 As shown, a first groove 1211 is provided on one side of the aforementioned carrier adhesive film 121, arranged at intervals, and the aforementioned solder strip 122 is embedded in the aforementioned first groove 1211. A plurality of first grooves 1211 are arranged alternately, thereby causing the solder strip 122 disposed in the first groove 1211 to be arranged alternately.

[0092] Furthermore, the upper surface of the aforementioned solder ribbon 122 may protrude beyond the first groove 1211, that is, higher than the surface of the carrier adhesive film 121 where the solder ribbon 122 is disposed, so as to form a strong electrical connection between the solder ribbon 122 and the BC cell 11 when the photovoltaic module is fabricated using the cell string 1. Here, the upper surface of the solder ribbon 122 refers to the side of the solder ribbon 122 that is close to the BC cell 11.

[0093] In addition, the upper surface of the solder ribbon 122 can be lower than the surface of the carrier adhesive film 121 where the solder ribbon 122 is provided or flush with the surface of the carrier adhesive film 121 where the solder ribbon 122 is provided, so that the thickness of the solder ribbon 122 contained in the first groove 1211 does not need to be considered, and the solder ribbon 122 can be provided in a variety of ways.

[0094] The aforementioned metal conductive paste 123 is in direct contact with its corresponding first conductive structure or second conductive structure, thereby achieving electrical connection between the metal conductive paste 123 and the first conductive structure or the second conductive structure. This also allows the metal conductive paste 123 to be firmly connected to the first conductive structure or the second conductive structure after curing, reducing the possibility of detachment or unstable electrical connection between the metal electrode formed after curing the metal conductive paste 123 and the BC battery cell 11.

[0095] Optionally, the first groove 1211 can be a V-shaped groove or an arc-shaped groove with a cross-section that gradually decreases from top to bottom, but is not limited to these. It is understood that the V-shaped groove or arc-shaped groove can regulate the propagation and reflection of sunlight, as can be seen from... Figure 4 The incident light rays that hit the first groove 1211 can be reflected by the side wall of the first groove 1211 to the back of the BC battery cell 11, thereby increasing the amount of sunlight reflected to the back of the BC battery cell 11 and improving the photoelectric conversion efficiency of the BC battery cell 11.

[0096] Furthermore, the aforementioned solder strip 122 is matched with the first groove 1211. Specifically, the shape of the solder strip 122 disposed in the first groove 1211 can match the shape of the first groove 1211, so as to limit the solder strip 122 by the first groove 1211 and reduce the probability of the solder strip 122 shifting during the battery string 1 preparation process.

[0097] Furthermore, the solder ribbon 122 and the carrier film 121 can be fixedly connected or detachably connected. When the solder ribbon 122 is fixed within the first groove 1211 of the carrier film 121, the problem of solder ribbon 122 shifting during the manufacturing process can be solved. When the solder ribbon 122 and the carrier film 121 are detachably connected, it is convenient to replace the solder ribbon 122 in the carrier film 121. If the solder ribbon 122 has a problem, it can be replaced between the manufacturing of photovoltaic modules, which can effectively improve the yield of the cell string 1.

[0098] In an optional embodiment, the contact area between each of the aforementioned solder ribbons 122 and the aforementioned BC battery cell 11 is smaller than the area of ​​the aforementioned P-type region 111 or the aforementioned N-type region 112 corresponding to the aforementioned solder ribbon 122. Specifically, the width of the first groove 1211 can be set to be less than or equal to the width of the corresponding aforementioned P-type region 111 or the aforementioned N-type region 112, so that the contact area between the solder ribbon 122 and the BC battery cell 11 is smaller than the area of ​​the corresponding P-type region 111 or N-type region 112, thereby preventing the solder ribbons 122 corresponding to adjacent N-type regions 112 and P-type regions 111 from contacting in the gap region 113 between the two regions and causing leakage. It can also make the metal conductive paste 123 contact the P-type region 111 or N-type region 112.

[0099] In one alternative embodiment, such as Figure 7 As shown, the extension direction of the solder strip 122 is consistent with the extension direction of the P-type region 111 and the N-type region 112. That is, the solder strip 122 in the connection structure 12 is correspondingly arranged with the P-type region 111 and the N-type region 112 in the BC battery cell 11. The distance between two adjacent solder strips 122 is greater than or equal to the distance between adjacent P-type region 111 and N-type region 112 in the BC battery cell 11. Any P-type region 111 or N-type region 112 in each BC battery cell 11 is electrically connected to a solder strip 122 so that current collection and transmission can be achieved through the solder strip 122 during operation.

[0100] In addition, such as Figure 8 As shown, the extension direction of the solder ribbons 122 is perpendicular to the extension directions of the P-type region 111 and the N-type region 112. Any P-type region 111 or N-type region 112 in each BC battery cell 11 is electrically connected to multiple solder ribbons 122. It is worth noting that the multiple solder ribbons 122 electrically connected to the P-type region 111 of a BC battery cell 11 are electrically isolated from the N-type region 112 of that BC battery cell 11.

[0101] In other words, Figure 8 In the structure shown, at the contact portion between a BC battery cell 11 and the connecting structure 12, each solder strip 122 is electrically connected only to either the P-type region 111 or the N-type region 112. However, since the extension direction of the solder strip 122 is perpendicular to the extension direction of the P-type region 111 and the N-type region 112, each solder strip 122 may intersect with both the P-type region 111 and the N-type region 112 simultaneously. Therefore, to prevent leakage, an insulating layer can be provided in the area where there is no need to be electrically connected to the solder strip 122. For example, if a solder strip 122 is electrically connected to the P-type region 111 of a BC battery cell 11, an insulating layer is provided between the N-type region 112 of the BC battery cell 11 and the solder strip 122.

[0102] Specifically, to prevent leakage, when the solder ribbon 122 is electrically connected to the first conductive structure of the P-type region 111 in the BC battery cell 11, a first insulating layer 1124 can be provided at the location where the conductive structure of the N-type region 112 intersects with the solder ribbon 122; when the solder ribbon 122 is electrically connected to the second conductive structure of the N-type region 112 in the BC battery cell 11, a second insulating layer can be provided at the location where the first conductive structure of the P-type region 111 intersects with the solder ribbon 122. As an example, such as... Figure 9 As shown, if a solder ribbon 122 is electrically connected to the P-type region 111 in the BC battery cell 11, a first insulating layer 1124 is provided at the intersection of the N-type region 112 and the solder ribbon 122. The first insulating layer 1124 is provided outside the second conductive structure of the N-type region 112 to separate the solder ribbon 122 and the metal conductive paste 123 outside the solder ribbon 122 from the second conductive structure, so that the solder ribbon 122 and the metal conductive paste 123 outside the solder ribbon 122 can only be electrically connected to the first conductive structure of the P-type region 111 in the BC battery cell 11. As another example, if a solder ribbon 122 is electrically connected to the N-type region 112 in the BC battery cell 11, a second insulating layer is provided at the intersection of the P-type region 111 and the solder ribbon 122. The second insulating layer is provided outside the first conductive structure of the P-type region 111 to isolate the solder ribbon 122 and the metal conductive paste 123 outside the solder ribbon 122 from the first conductive structure, so that the solder ribbon 122 and the metal conductive paste 123 outside the solder ribbon 122 can only be electrically connected to the second conductive structure of the N-type region 112 in the BC battery cell 11.

[0103] It should be noted that, Figure 7 and Figure 8 Only four BC battery cells 11 in battery string 1 are shown as an example. Figure 9 Only illustrative examples are shown. Figure 8 A schematic diagram of a partial cross-section along the middle AA.

[0104] In one alternative embodiment, such as Figure 1 As shown, a second groove 1221 is provided on one side of the solder strip 122; the conductive metal paste 123 is filled in the second groove 1221. Each solder strip 122 has a second groove 1221 for dispensing the conductive metal paste 123 on the side away from the carrier film. The shape of the second groove 1221 can be U-shaped, but is not limited to this.

[0105] The aforementioned conductive metal paste 123 includes, but is not limited to, silver paste, silver-aluminum paste, copper paste, or silver-coated copper paste. It is understood that the conductive metal paste 123 in different second grooves 1221 of the same connection structure 12 can be made of the same material or different materials. Generally, the same material can be selected to simplify the preparation process of the battery string 1.

[0106] Optionally, the metal conductive paste 123 can be a low-temperature curing conductive paste, which can be cured under the lamination temperature conditions, so that the metal conductive paste 123 can be tightly connected to the BC battery cell 11 and the solder ribbon 122 at the same time. The cured electrode forms a tight connection between the BC battery cell 11 and the connection structure 12, reducing the possibility of the connection structure 12 falling off from the BC battery cell 11.

[0107] In one alternative embodiment, such as Figure 7 and Figure 8 As shown, the edge of the carrier film 121 extends beyond the edge of the BC cell 11, meaning the area of ​​the carrier film 121 is larger than the area of ​​the multiple BC cell 11 connected in series. This allows the carrier film 121 to completely cover the back of the BC cell 11. After the photovoltaic module is manufactured, the edge of the carrier film 121 can be tightly fitted with the edge of the upper encapsulation film 3 and the backplate 4, preventing moisture and dust from seeping in from the edge during the use of the photovoltaic module and affecting its performance and lifespan.

[0108] According to the battery string 1 of this utility model embodiment, by setting solder ribbons 122 spaced apart on one side of the carrier adhesive film 121 in the connection structure 12, and setting a metal conductive paste 123 on the outside of the solder ribbons 122, metal electrodes can be omitted in the BC battery cell 11, simplifying the structure of the BC battery cell 11. Furthermore, by setting the metal conductive paste 123 on the outside of the solder ribbons 122, a tight contact between the solder ribbons 122 and the metal conductive paste 123 is achieved. In the photovoltaic module prepared using this battery string 1, there is a strong mechanical connection between the electrode and the solder ribbons 122, reducing the possibility of poor contact or detachment between the solder ribbons 122 and the electrode, maintaining the integrity of the photovoltaic module structure, effectively extending the service life of the photovoltaic module, and enhancing the performance of the photovoltaic module.

[0109] like Figure 10 As shown, this utility model embodiment provides a photovoltaic module, including: a cover plate 2, an upper encapsulation film 3, a back plate 4, and at least one battery string 1 according to this utility model embodiment.

[0110] The upper encapsulating film 3 is disposed between the cover plate 2 and the plurality of battery strings 1; at least one battery string 1 is disposed between the upper encapsulating film 3 and the back plate 4, that is, the cover plate 2, the upper encapsulating film 3, the battery strings 1 and the back plate 4 are stacked sequentially in the photovoltaic module. The connection structure 12 of the battery strings 1 faces the back plate 4.

[0111] Specifically, the battery string 1 includes multiple BC battery cells 11 and a connection structure 12 according to this embodiment of the invention. The BC battery cells 11 are in contact with the upper encapsulation film 3, and the connection structure 12 is in contact with the backplate 4. The back surface of the BC battery cells 11 includes: alternating P-type regions 111 and N-type regions 112, a first conductive structure disposed in the P-type regions 111, and a second conductive structure disposed in the N-type regions 112. The first conductive structure and the second conductive structure are electrically isolated. The connection structure 12 includes: a carrier adhesive film 121, solder ribbons 122, and a metal conductive paste 123; the carrier adhesive film 121 is used to cover the back of the plurality of BC battery cells 11; the plurality of solder ribbons 122 are spaced apart on the side of the carrier adhesive film 121 that contacts the back of the BC battery cell 11; the metal conductive paste 123 is disposed on the side of the solder ribbons 122 that does not contact the carrier adhesive film 121, and the metal conductive paste 123 is used to connect the solder ribbons 122 to the BC battery cell 11.

[0112] The cover plate 2 and the back plate 4 can be made of glass or organic materials, but are not limited to these. As an example, when the cover plate 2 and the back plate 4 are made of organic materials, polyvinylidene fluoride, polyvinylidene fluoride, etc., can be used. Optionally, the surfaces of the cover plate 2 and the back plate 4 can also be provided with a covering film layer with various functions or properties, such as an anti-reflective film.

[0113] The encapsulating film 3 may include one or more of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), and expandable polyethylene (EPE).

[0114] In an optional embodiment, the aforementioned conductive metal paste 123 is in direct contact with its corresponding first conductive structure or second conductive structure. Specifically, when fabricating a photovoltaic module using the battery string 1 of this embodiment, the conductive metal paste 123 in the connection structure 12 is cured to form an electrode. For each pair of adjacent BC battery cells 11, the first conductive structure of one BC battery cell 11 and the second conductive structure of the other BC battery cell 11 are connected to a solder strip 122 in the carrier adhesive film 121 through the conductive metal paste 123 on the solder strip 122, so as to connect multiple BC battery cells 11 in series and collect charge from the BC battery cells 11 through the electrode. In order to ensure that the electrode formed by the conductive metal paste 123 on the outside of the solder strip 122 is in close contact with the BC battery cell 11, the conductive metal paste 123 is in direct contact with the corresponding first conductive structure or second conductive structure, so that the solder strip 122 can effectively combine with the BC battery cell 11 through the metal electrode formed after the conductive metal paste 123 is cured, thereby realizing the function of the solder strip 122 collecting current.

[0115] It should be noted that in the finished photovoltaic module of this utility model embodiment, since it has undergone heat treatment or lamination treatment, the metal conductive paste 123 therein has been transformed into electrodes.

[0116] According to the photovoltaic module of this utility model embodiment, by adopting the battery string 1 of this utility model embodiment, the lower encapsulation film is saved, and the battery string 1 can be directly stacked with the cover plate 2, the upper encapsulation film 3, and the back plate 4 to form a photovoltaic module, which greatly simplifies the structure of the photovoltaic module.

[0117] Meanwhile, by using a battery string 1 with a metal conductive paste 123 on the outside of the solder strip 122, a close contact between the solder strip 122 and the metal conductive paste 123 is achieved. In the photovoltaic module made using this battery string 1, there is a strong mechanical connection between the electrode and the solder strip 122, which reduces the possibility of poor contact or detachment between the solder strip 122 and the electrode. This can maintain the integrity of the photovoltaic module structure, effectively extend the service life of the photovoltaic module, and enhance the performance of the photovoltaic module.

[0118] This utility model embodiment provides a method for preparing a photovoltaic module, including: sequentially laying a backsheet 4, a connecting structure 12, a BC cell unit 11, an upper encapsulating film 3, and a cover plate 2, followed by lamination to complete the preparation of the photovoltaic module.

[0119] In one optional embodiment, the backplate 4, the connecting structure 12, and the BC battery cells 11 are sequentially laid to form a battery string 1 on the backplate 4, mainly including the following steps A1 to A3:

[0120] Step A1: A plurality of BC battery cells 11 are laid on the back plate 4. The back of the BC battery cell 11 includes: P-type regions 111 and N-type regions 112 arranged alternately, a first conductive structure disposed in the P-type region 111 and a second conductive structure disposed in the N-type region 112, wherein the first conductive structure and the second conductive structure are electrically isolated.

[0121] The BC battery cell 11 can be prepared by the following method: alternating P-type regions 111 and N-type regions 112 are prepared on the back side of the silicon substrate 114, and a first conductive structure is provided in the P-type region 111 and a second conductive structure is provided in the N-type region 112 to form the BC battery cell 11.

[0122] The silicon substrate 114 can be an N-type silicon substrate or a P-type silicon substrate.

[0123] Alternating P-type doped polysilicon layers 1112 and N-type doped polysilicon layers 1122 are formed on the back side of the silicon substrate 114, wherein the region containing the P-type doped polysilicon layer 1112 is the P-type region 111, and the region containing the N-type doped polysilicon layer 1122 is the N-type region 112.

[0124] Furthermore, other functional membrane layers can be provided in the P-type region 111 and the N-type region 112.

[0125] The first conductive structure is disposed outside the P-type doped polysilicon layer 1112 of the P-type region 111, that is, on the side of the P-type doped polysilicon layer 1112 away from the silicon substrate 114. Similarly, the second conductive structure is disposed outside the N-type doped polysilicon layer 1122 of the N-type region 112, that is, on the side of the N-type doped polysilicon layer 1122 away from the silicon substrate 114.

[0126] Optionally, a spacer region 113 can be provided between the alternating P-type regions 111 and N-type regions 112 to separate the P-type regions 111 and N-type regions 112 and prevent leakage. Specifically, the spacer region 113 is formed by removing a portion of the P-type doped polysilicon layer 1112 and the first transparent conductive layer 1111 adjacent to the N-type region 112 in the P-type region 111, or by removing a portion of the N-type doped polysilicon layer 1122 and the second transparent polysilicon layer adjacent to the P-type region 111 in the N-type region 112. The spacer region 113 does not contain either the P-type doped polysilicon layer 1112 or the N-type doped polysilicon layer 1122.

[0127] Step A2: A plurality of spaced solder strips 122 are arranged on one side of the carrier adhesive film 121, and a metal conductive paste 123 is arranged on the outside of the solder strips 122 to form a connection structure 12.

[0128] The aforementioned carrier film 121 includes one or more of the following: ethylene-vinyl acetate copolymer, polyolefin elastomer, and polyethylene foam. The aforementioned metal conductive paste 123 includes: silver paste, silver-aluminum paste, copper paste, or silver-coated copper paste.

[0129] Optionally, the metal conductive paste 123 can be a low-temperature curing conductive paste, which allows the metal conductive paste 123 to be cured under the lamination temperature conditions, so that the metal conductive paste 123 can be tightly connected to the BC battery cell 11 and the solder ribbon 122 at the same time, reducing the possibility of the connection structure 12 and the BC battery cell 11 falling off, and also reducing the possibility of the metal conductive paste 123 falling off from the solder ribbon 122.

[0130] Step A3: The carrier adhesive film 121 included in the connection structure 12 is covered on the back of a plurality of BC battery cells 11, wherein the solder ribbon 122 included in the connection structure 12 and the outer side of the solder ribbon 122 are provided with a metal conductive paste 123 to electrically connect each two adjacent BC battery cells 11 to form a battery string 1.

[0131] Specifically, the side of the connecting structure 12 with the solder strip 122 faces the BC battery cell 11, so that the connecting structure 12 covers the back of several of the BC battery cells 11. For each pair of adjacent BC battery cells 11, the first conductive structure of one BC battery cell 11 and the second conductive structure of the other BC battery cell 11 are connected to a solder strip 122 in the carrier adhesive film 121 through a metal conductive paste 123 on the solder strip 122, so as to connect multiple BC battery cells 11 in series, thereby forming a battery string 1 on the back plate 4.

[0132] In an optional embodiment, the preparation of the connecting structure 12 in step A2 above may include the following steps A21 to A24:

[0133] Step A21: The raw material of the above-mentioned carrier film 121 is melted and extruded to obtain the initial carrier film; the first groove 1211 is not provided in the above-mentioned initial carrier film;

[0134] Step A22: Before the temperature of the initial carrier film drops to room temperature, the solder ribbons 122 are placed on the initial carrier film at intervals, wherein the positions of the solder ribbons 122 correspond to the P-type region 111 and the N-type region 112 in the BC battery cell 11.

[0135] Step A23: The solder ribbon 122 is embedded into the initial carrier adhesive film by pressing, thereby obtaining a carrier adhesive film 121 with a first groove 1211 and the solder ribbon 122 is embedded in the first groove 1211.

[0136] Step A24: A second groove 1221 is formed on the side of the solder strip 122 that does not contact the carrier adhesive film 121, and the metal conductive paste 123 is placed in the second groove 1221 to obtain the connection structure 12.

[0137] The initial carrier film obtained by extrusion molding still has a certain degree of plasticity before the temperature drops to room temperature, allowing the solder ribbon 122 to be embedded into the initial carrier film after extrusion molding. Specifically, according to the positions of the P-type region 111 and N-type region 112 in the BC battery, the solder ribbon 122 is placed at the corresponding position on the initial carrier film. The solder ribbon 122 can be embedded into the initial carrier film by pressing, and a first groove 1211 is formed in the carrier film 121 at the position where the solder ribbon 122 is located. This simplifies the embedding process of the solder ribbon 122, eliminating the need to prepare the first groove 1211 before embedding the solder ribbon 122.

[0138] The second groove 1221 can be formed by means of laser or other methods, and no specific limitation is made here. The width of the second groove 1221 is smaller than the width of the first groove 1211, so that the solder ribbon 122 can contact the first conductive structure and the second conductive structure in the BC battery cell 11.

[0139] The conductive metal paste 123 can be applied to the second groove 1221 by coating or printing.

[0140] In an optional embodiment, the preparation of the connecting structure 12 in step A2 may specifically include the following steps A21' to A23':

[0141] Step A21': Melt the raw material of the above-mentioned carrier film 121;

[0142] Step A22': The solder ribbons 122 are placed at intervals on the surface of the molten carrier film 121 raw material, wherein the positions of the solder ribbons 122 correspond to the positions of the P-type region 111 and the N-type region 112 in the BC battery cell 11, and the carrier film 121 with the first groove 1211 and the solder ribbons 122 are embedded in the first groove 1211 is obtained by extrusion molding;

[0143] Step A23': A second groove 1221 is formed on the side of the solder strip 122 that does not contact the carrier adhesive film 121, and the metal conductive paste 123 is placed in the second groove 1221 to obtain the connection structure 12.

[0144] By placing the welding ribbon 122 in the corresponding position before extrusion molding, the welding ribbon 122 can be embedded into the carrier film 121 during the extrusion molding process. The carrier film 121 with the welding ribbon 122 is directly obtained through extrusion molding, which simplifies the process of embedding the welding ribbon 122 into the carrier film 121.

[0145] The second groove 1221 can be formed by means of laser or other methods, and no specific limitation is made here. The width of the second groove 1221 is smaller than the width of the first groove 1211, so that the solder ribbon 122 can contact the first conductive structure and the second conductive structure in the BC battery cell 11.

[0146] The conductive metal paste 123 can be applied to the second groove 1221 by coating or printing.

[0147] It should be noted that the preparation method of the connecting structure 12 is not limited to the embodiments listed above. For example, the preparation method of the connecting structure 12 may also include: pre-adjusting the extrusion mold used to prepare the carrier adhesive film 121, melting the raw material of the carrier adhesive film 121, and obtaining the carrier adhesive film 121 with a first groove 1211 by extrusion molding; embedding the solder ribbon 122 in the first groove 1211; forming a second groove 1221 on the side of the solder ribbon 122 that does not contact the carrier adhesive film 121, and setting the metal conductive paste 123 in the second groove 1221, thereby obtaining the connecting structure 12.

[0148] It should be noted that if the battery string 1 formed through steps A1 to A3 cannot be used immediately for photovoltaic module fabrication, it can be heat-treated to solidify the conductive metal paste 123 within it into electrodes. This ensures a tight connection between the solder ribbon 122 and the electrodes, preventing the oxidation, diffusion, or loss of the conductive metal paste 123 that can occur if the battery string 1 is left untreated for an extended period. Then, the heat-treated battery string 1 can be used to fabricate photovoltaic modules. Since the conductive metal paste 123 has already solidified into electrodes, the temperature during the lamination process will not affect the electrodes or the solder ribbon 122.

[0149] Optionally, the heat treatment temperature can be 120℃-200℃, and the heat treatment time can be 5min-30min. As an example, the heat treatment temperature can be 120℃, 130℃, 150℃, 160℃, 180℃, or 200℃, etc.; the heat treatment time can be 5min, 10min, 13min, 17min, 22min, 25min, or 30min, etc.

[0150] Preferably, the heat treatment temperature can be 150°C and the heat treatment time can be 15 minutes, so that the curing effect of the metal slurry can reach the optimal state.

[0151] According to the battery string preparation method of this utility model embodiment, by setting a solder ribbon 122 on the carrier adhesive film 121 and setting a metal conductive paste 123 on the outside of the solder ribbon 122 to form a connection structure 12, the step of printing paste in the BC battery cell 11 to form electrodes can be omitted, thereby reducing the preparation cost.

[0152] In an optional embodiment, during the lamination process, the upper encapsulation film 3 and the carrier film 121 in the battery string 1 can form a solid whole with the BC battery cell 11 and fit tightly with the cover plate 2 and the back plate 4 to seal the BC battery cell 11 and prevent it from being affected by external environmental factors (such as moisture, dust, etc.) during the use of the photovoltaic module.

[0153] Furthermore, during the lamination process, the lamination temperature causes the conductive metal paste 123 to solidify and form electrodes, which are then tightly connected to the BC cell 11 and the solder ribbon 122. This directly establishes a stable mechanical connection between the electrodes and the solder ribbon 122, and between the electrodes and the BC cell 11, reducing the possibility of poor contact and detachment between the solder ribbon 122 and the electrodes. Moreover, by using lamination to solidify the conductive metal paste 123 into electrodes and weld the solder ribbon 122, the steps of paste printing and drying / curing during the preparation of the BC cell 11 with electrodes can be omitted, as can the step of welding the solder ribbon 122 during the preparation of the cell string 1. This eliminates the need for a drying sintering machine and a string welding machine, reducing preparation costs, shortening preparation time, and greatly simplifying the photovoltaic module manufacturing process.

[0154] Optionally, the lamination temperature can be 130℃-200℃, and the lamination time can be 10min-30min. As an example, the lamination temperature can be 130℃, 150℃, 165℃, 175℃, 185℃, or 200℃, etc.; the lamination time can be 10min, 15min, 20min, 25min, or 30min, etc.

[0155] Preferably, the lamination temperature can be 150°C and the lamination time can be 15 minutes, so that the lamination effect and the curing effect of the metal slurry can both reach the optimal state.

[0156] The number of cell strings and the series-parallel connection method in a photovoltaic module can be set according to the actual situation, and no specific limit is made here.

[0157] According to the photovoltaic module manufacturing method of this utility model embodiment, the metal conductive paste 123 is cured by the lamination temperature to form an electrode in close contact with the solder ribbon 122, which reduces the possibility of poor contact between the electrode and the solder ribbon 122 and easy detachment. At the same time, the curing of the metal conductive paste 123 and the welding of the solder ribbon 122 to the electrode are directly achieved by using the lamination temperature, which omits the steps of drying and curing the metal conductive paste 123 and welding the solder ribbon 122. There is no need to use a drying sintering machine and a string welding machine, which further reduces the manufacturing cost, shortens the manufacturing time, and greatly simplifies the manufacturing process of photovoltaic modules.

[0158] The following two specific examples illustrate the preparation method of photovoltaic modules.

[0159] Example 1

[0160] Step C1: Alternating P-type regions 111 and N-type regions 112 are formed on the back side of the silicon substrate 114, and a first transparent conductive layer 1111 is provided in the P-type region 111 and a second transparent conductive layer 1121 is provided in the N-type region 112 to form a BC battery cell 11; the BC battery cell 11 has no electrodes.

[0161] In the P-type region 111, an intrinsic hydrogenated silicon layer 1113, a P-type doped polysilicon layer 1112, and a first transparent conductive layer 1111 are sequentially disposed in the direction away from the silicon substrate 114; in the N-type region 112, a first tunneling oxide layer 1123, an N-type doped polysilicon layer 1122, and a second transparent conductive layer 1121 are sequentially disposed in the direction away from the silicon substrate 114.

[0162] An interval region 113 is provided between adjacent P-type regions 111 and N-type regions 112. Specifically, the interval region 113 is formed by removing a portion of the P-type doped polysilicon layer 1112 and the first transparent conductive layer 1111 adjacent to the N-type region 112 in the P-type region 111, or by removing a portion of the N-type doped polysilicon layer 1122 and the second transparent polysilicon layer adjacent to the P-type region 111 in the N-type region 112. The interval region 113 does not contain either the P-type doped polysilicon layer 1112 or the N-type doped polysilicon layer 1122.

[0163] Step C2: Melt the raw material of the above-mentioned carrier film 121 and obtain an initial carrier film by extrusion molding; before the temperature of the above-mentioned initial carrier film drops to room temperature, place the above-mentioned solder ribbons 122 at intervals on the above-mentioned initial carrier film, wherein the positions of the above-mentioned solder ribbons 122 correspond to the above-mentioned P-type region 111 and the above-mentioned N-type region 112 in the above-mentioned BC battery cell 11; embed the above-mentioned solder ribbons 122 into the above-mentioned initial carrier film by pressing, thereby obtaining a carrier film 121 with a first groove 1211 and the above-mentioned solder ribbons 122 embedded in the first groove 1211; form a second groove 1221 on the side of the above-mentioned solder ribbons 122 that do not contact the carrier film, and apply the above-mentioned metal conductive paste 123 in the second groove 1221 by coating to form a connection structure 12;

[0164] Step C3: Arrange multiple BC battery cells 11 sequentially and lay them on the surface of the connecting structure 12, so that the P-type region 111 and N-type region 112 of the BC battery cell 11 correspond to the solder ribbon 122, forming as shown. Figure 4 Battery string 1 shown;

[0165] In battery string 1, adjacent BC battery cells 11 are arranged closely together. For each solder ribbon 122, one end corresponds to the first transparent conductive layer 1111 of one of the two adjacent BC battery cells 11, and the other end corresponds to the second transparent conductive layer 1121 of the other of the two adjacent BC battery cells 11. Thus, for each pair of adjacent BC battery cells 11, the first transparent conductive layer 1111 of one BC battery cell 11 and the second transparent conductive layer 1121 of the other BC battery cell 11 are connected to a solder ribbon 122 in the carrier adhesive film 121 through the metal conductive paste 123 on the solder ribbon 122, so as to connect multiple BC battery cells 11 in series.

[0166] Step C4: Heat-treat the battery string 1 to solidify the metal conductive paste 123 therein to form an electrode;

[0167] The heat treatment temperature was 150℃ and the time was 15 minutes.

[0168] Step C5: Lay several heat-treated battery strings 1 on the backplate 4, and then lay encapsulating film 3 and cover plate 2 on the battery strings 1 in sequence. After lamination, a photovoltaic module is obtained.

[0169] Example 2

[0170] Step D1: Melt the raw material of the above-mentioned carrier film 121; place the above-mentioned solder ribbons 122 at intervals on the surface of the molten raw material, wherein the position of the above-mentioned solder ribbons 122 corresponds to the position of the above-mentioned P-type region 111 and the above-mentioned N-type region 112 in the above-mentioned BC battery cell 11, and obtain a carrier film 121 with a first groove 1211 and the above-mentioned solder ribbons 122 embedded in the first groove 1211 by extrusion molding; form a second groove 1221 on the side of the above-mentioned solder ribbons 122 that do not contact the carrier film, and apply the above-mentioned metal conductive paste 123 in the second groove 1221 by printing to form a connection structure 12;

[0171] Step D2: Lay the connecting structure 12 on the back plate 4, with the side of the connecting structure 12 without the welding strip 122 attached to the surface of the back plate 4.

[0172] Step D3: Alternating P-type regions 111 and N-type regions 112 are formed on the back side of the silicon substrate 114, and a first transparent conductive layer 1111 is provided in the P-type region 111, and a second transparent conductive layer 1121 is provided in the N-type region 112 to form a BC battery cell 11; the BC battery cell 11 has no electrodes.

[0173] In the P-type region 111, a second tunneling oxide layer 1114, a P-type doped polysilicon layer 1112, and a first transparent conductive layer 1111 are sequentially disposed in the direction away from the silicon substrate 114; in the N-type region 112, a second tunneling oxide layer 1114, an N-type doped polysilicon layer 1122, and a second transparent conductive layer 1121 are sequentially disposed in the direction away from the silicon substrate 114.

[0174] An interval region 113 is provided between adjacent P-type regions 111 and N-type regions 112. Specifically, the interval region 113 is formed by removing a portion of the P-type doped polysilicon layer 1112 and the first transparent conductive layer 1111 adjacent to the N-type region 112 in the P-type region 111, or by removing a portion of the N-type doped polysilicon layer 1122 and the second transparent polysilicon layer adjacent to the P-type region 111 in the N-type region 112. The interval region 113 does not contain either the P-type doped polysilicon layer 1112 or the N-type doped polysilicon layer 1122.

[0175] Step D4: Lay the BC battery cell 11 on the connecting structure 12 so that the P-type region 111 and N-type region 112 of the BC battery cell 11 correspond to the solder ribbon 122, forming as shown. Figure 5 Battery string 1 shown;

[0176] In battery string 1, adjacent BC battery cells 11 are arranged closely together. For each solder ribbon 122, one end corresponds to the first transparent conductive layer 1111 of one of the two adjacent BC battery cells 11, and the other end corresponds to the second transparent conductive layer 1121 of the other of the two adjacent BC battery cells 11. Thus, for each pair of adjacent BC battery cells 11, the first transparent conductive layer 1111 of one BC battery cell 11 and the second transparent conductive layer 1121 of the other BC battery cell 11 are connected to a solder ribbon 122 in the carrier adhesive film 121 through the metal conductive paste 123 on the solder ribbon 122, so as to connect multiple BC battery cells 11 in series.

[0177] Step D5: Lay several battery strings 1 on the backplate 4, with the side of the connecting structure 12 in the battery string 1 facing the backplate 4; then, sequentially stack the encapsulating film 3 and the cover plate 2 on the battery string 1, and after lamination, obtain the photovoltaic module.

[0178] The lamination process was carried out at a temperature of 190℃ for 20 minutes.

[0179] During the lamination process, the upper encapsulating film 3 and the carrier film 121 in the battery string 1 can form a solid whole with the BC battery cell 11 and fit tightly with the cover plate 2 and the back plate 4 to seal the BC battery cell 11. At the same time, the lamination temperature causes the metal conductive paste 123 to solidify and form an electrode, which is tightly connected to the BC battery cell 11 and the solder ribbon 122. A stable mechanical connection is directly formed between the electrode and the solder ribbon 122, and between the electrode and the BC battery cell 11, reducing the possibility of poor contact and detachment between the solder ribbon 122 and the electrode.

[0180] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A connection structure, characterized in that, The connection structure (12) is used to connect multiple BC battery cells (11) in series, including: A carrier adhesive film (121) is used to cover the back side of the plurality of BC battery cells (11); Solder strips (122), multiple solder strips (122) are spaced apart on the side of the carrier adhesive film (121) that contacts the back of the BC battery cell (11); Metal conductive paste (123) is disposed on the side of the solder ribbon (122) that is not in contact with the carrier adhesive film (121). The metal conductive paste (123) is used to connect the solder ribbon (122) to the BC battery cell (11).

2. The connection structure according to claim 1, characterized in that, The carrier adhesive film (121) has a first groove (1211) arranged at intervals on one side, and the welding strip (122) is embedded in the first groove (1211).

3. The connection structure according to claim 1 or 2, characterized in that, A second groove (1221) is provided on the side of the solder strip (122) that does not contact the carrier adhesive film (121), and the metal conductive paste (123) is filled in the second groove (1221).

4. The connection structure according to claim 2, characterized in that, The first groove (1211) is a V-shaped groove or an arc-shaped groove whose cross-section gradually decreases from top to bottom, and the welding strip (122) matches the first groove (1211).

5. A battery string, characterized in that, include: Multiple BC battery cells (11) and the connection structure (12) according to any one of claims 1-4, wherein, The back side of the BC battery cell (11) includes: alternating P-type regions (111) and N-type regions (112), a first conductive structure disposed in the P-type region (111) and a second conductive structure disposed in the N-type region (112), wherein the first conductive structure and the second conductive structure are electrically isolated. The carrier adhesive film (121) of the connection structure (12) covers the back of the plurality of BC battery cells (11); For each pair of adjacent BC battery cells (11), the first conductive structure of one BC battery cell (11) and the second conductive structure of the other BC battery cell (11) are connected to a solder strip (122) in the carrier adhesive film (121) through a metal conductive paste (123) on the solder strip (122) to connect multiple BC battery cells (11) in series.

6. The battery string according to claim 5, characterized in that, The first conductive structure is a first transparent conductive layer (1111), the second conductive structure is a second transparent conductive layer (1121), and the metal conductive paste (123) on the solder strip (122) is directly connected to its corresponding first transparent conductive layer (1111) or second transparent conductive layer (1121); or, The first conductive structure includes a first transparent conductive layer (1111) and a first electrode disposed on the first transparent conductive layer (1111). The second conductive structure includes a second transparent conductive layer (1121) and a second electrode disposed on the second transparent conductive layer (1121). The metal conductive paste (123) on the solder ribbon (122) is directly connected to its corresponding first electrode or second electrode.

7. The battery string according to claim 5, characterized in that, The first conductive structure is the first electrode, the second conductive structure is the second electrode, and the metal conductive paste (123) on the solder strip (122) is directly connected to its corresponding first electrode or second electrode.

8. The battery string according to claim 6, characterized in that, The back side of the BC battery cell (11) also includes a second tunneling oxide layer (1114) disposed in the P-type region (111) and the N-type region (112); the second tunneling oxide layer (1114) is in contact with the silicon substrate (114); or, The back side of the BC battery cell (11) also includes an intrinsic silicon hydrogenation layer (1113) disposed in the P-type region (111) and a first tunneling oxide layer (1123) disposed in the N-type region (112). The intrinsic silicon hydrogenation layer (1113) and the first tunneling oxide layer (1123) are in contact with the silicon substrate (114).

9. The battery string according to claim 7, characterized in that, The back side of the BC battery cell (11) also includes a second tunneling oxide layer (1114) disposed in the P-type region (111) and the N-type region (112), the second tunneling oxide layer (1114) being in contact with the silicon substrate (114); a first passivation antireflection layer disposed inside the first conductive structure in the P-type region (111), and a second passivation antireflection layer disposed inside the second conductive structure in the N-type region (112).

10. A photovoltaic module, characterized in that, include: Cover plate (2), upper encapsulation film (3), back plate (4) and at least one battery string (1) according to any one of claims 5-9; The upper encapsulation film (3) is disposed between the cover plate (2) and at least one of the battery strings (1); At least one of the battery strings (1) is disposed between the upper encapsulation film (3) and the backplate (4); The connection structure (12) of the battery string (1) faces the side of the back plate (4).

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