Battery string, photovoltaic module and preparation method of battery string

Abstract

The invention discloses a battery string, a photovoltaic module and a preparation method of the battery string, and relates to the technical field of photovoltaics. The battery string comprises a plurality of battery pieces, and transparent conductive films are arranged on the front surfaces and the back surfaces of the battery pieces; the first metal wire mesh is laid on the front surface of each battery piece and is electrically connected with the transparent conductive thin film on the front surface of the battery piece; the second metal wire mesh is laid on the back surface of each battery piece and is electrically connected with the back surface of the battery piece; and a plurality of bus bars. For every two adjacent battery pieces, the first metal wire mesh on one battery piece and the second metal wire mesh on the other adjacent battery piece are electrically connected with the same bus bar so as to connect a plurality of battery pieces in series. The metal wire mesh in the battery string is not easy to bend, small in stress and high in reliability.

Description

Technical Field

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

[0002] With the development of photovoltaic technology, in order to achieve the goal of reducing costs and increasing efficiency, busbar-free photovoltaic cells came into being. The core of this technology is to abandon the busbar on the surface of the cell and collect current through welding strips or metal mesh.

[0003] When the current of a busbar-less cell is collected through a welding ribbon, the welding ribbon is alloyed with the fine grid. At this time, a large number of fine grids cannot achieve the purpose of reducing the cost of silver paste, and the width of the fine grid is generally 20~28μm, which will block the sunlight and cause efficiency loss of the cell. In addition, the welding ribbon is usually fixed by dispensing glue, which is easy to shift during the welding process. The welding ribbon and the fine grid are alloyed, the contact area is small, the reliability is low, and it is easy to cause the grid to break.

[0004] The prior art provides a photovoltaic module that uses a metal wire mesh to collect current, one end of the metal wire mesh is connected to the front of a cell in a cell string in the photovoltaic module, and the other end is connected to the back of an adjacent cell in the cell string. Although this connection method can reduce the amount of silver paste used, there are problems such as high stress on the metal wire mesh and low connection reliability. Summary of the invention

[0005] In view of this, the embodiments of the present invention provide a battery string, a photovoltaic module and a method for preparing the battery string, which can collect and transmit current without setting grid lines and welding strips on the surface of the battery cell, while reducing the cost of metal slurry.

[0006] To achieve the above object, according to one aspect of an embodiment of the present invention, a battery string is provided. A battery string according to an embodiment of the present invention comprises:

[0007] A plurality of battery cells, wherein transparent conductive films are provided on the front and back sides of the battery cells;

[0008] A first metal wire mesh laid on the front side of each of the battery cells and electrically connected to the transparent conductive film on the front side of the battery cells;

[0009] A second metal wire mesh laid on the back side of each of the above-mentioned battery cells and electrically connected to the back side of the above-mentioned battery cells;

[0010] and certain bus bars;

[0011] For every two adjacent battery cells, the first metal wire mesh on one battery cell and the second metal wire mesh on another adjacent battery cell are electrically connected to the same bus bar to connect a plurality of the battery cells in series.

[0012] To achieve the above object, according to another aspect of an embodiment of the present invention, a photovoltaic module is provided. A photovoltaic module according to an embodiment of the present invention includes: the battery string as described above.

[0013] To achieve the above object, according to another aspect of an embodiment of the present invention, a method for preparing a battery string is provided. A method for preparing a battery string according to an embodiment of the present invention comprises:

[0014] Step A1, laying the battery cell on the second metal wire mesh so that the back side of the battery cell contacts the second metal wire mesh;

[0015] Step A2, laying a first metal wire mesh on the front side of the battery cell;

[0016] Step A3, pressing and curing the battery sheet on which the first metal wire mesh and the second metal wire mesh are laid;

[0017] Step A4, testing and screening the cured battery cells;

[0018] Step A5: For adjacent screened battery cells, use a bus bar to electrically connect the second electrical connection portion of the first metal wire mesh of one of the above screened battery cells, and to electrically connect the bus bar to the fourth electrical connection portion of the second metal wire mesh of another above screened battery cell.

[0019] One embodiment of the above invention has the following advantages or beneficial effects: according to the battery string of the embodiment of the present invention, by laying a first metal wire mesh on the front side of the battery cell provided with a transparent conductive film, and laying a second metal wire mesh on the back side, the first metal wire mesh, the second metal wire mesh and the transparent conductive film are electrically connected, and current can be collected and transmitted without setting grid lines and welding strips on the surface of the battery cell, thereby reducing the cost of metal slurry.

[0020] By using a bus bar to connect the first metal wire mesh of one of two adjacent battery cells and the second metal wire mesh of the other battery cell, the battery cells are connected in series to form a battery string, which avoids the bending of the part of the metal wire mesh located between the two battery cells caused by connecting two adjacent battery cells through the same metal wire mesh, solves the problem of excessive stress in this part that reduces the reliability of the battery string, and improves the structural stability of the battery string.

[0021] In addition, the first metal wire mesh includes a first metal wire parallel to the first direction and a second metal wire parallel to the second direction, and the second metal wire mesh includes a third metal wire parallel to the first direction and a fourth metal wire parallel to the second direction, so that the first metal wire and the second metal wire extend in two directions perpendicular to each other, respectively, and the third metal wire and the fourth metal wire extend in two directions perpendicular to each other, respectively. The first metal wire mesh and the second metal wire mesh are in a mesh structure, which improves the current collection and transmission capacity. Neither a main grid nor a fine grid is required on the surface of the battery cell, which solves the problem of aligning the metal wire mesh with the fine grid during the preparation of the battery string. Moreover, by setting the first metal wire mesh and the second metal wire mesh in a mesh structure, the probe can be connected to the metal wire mesh extending in different directions during the IV test of the battery cell, which solves the problem that the battery cell without a grid line cannot pass the IV test for battery sorting.

[0022] The further effects of the above-mentioned non-conventional optional manner will be described below in conjunction with the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to better understand the present invention and do not constitute an improper limitation of the present invention.

[0024] Figure 1 is a schematic diagram of the longitudinal cross-sectional structure of a battery string according to an embodiment of the present invention;

[0025] Figure 2 is a top view of a battery string according to an embodiment of the present invention;

[0026] Figure 3 is a schematic structural diagram of a first metal wire mesh placed on the front side of a battery cell according to an embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of a structure in which a second metal wire mesh is placed on the back of a battery cell according to an embodiment of the present invention;

[0028] Figure 5 is a schematic diagram of the longitudinal cross-sectional structure of a battery cell on which a first metal wire mesh and a second metal wire mesh are laid according to an embodiment of the present invention;

[0029] Figure 6 is a structural diagram of a first metal wire mesh according to an embodiment of the present invention;

[0030] Figure 7 is an exploded schematic diagram of a photovoltaic assembly according to an embodiment of the present invention;

[0031] Figure 8 is a schematic flow chart of a method for preparing a battery string according to an embodiment of the present invention;

[0032] Fig. 9is a schematic flow chart of a method for preparing a battery string according to another embodiment of the present invention;

[0033] Fig.10 is a schematic diagram of a semi-finished structure of a battery string formed after laying a second metal wire mesh on a laminated film layer according to an embodiment of the present invention;

[0034] Fig.11 is a schematic diagram of the structure of a semi-finished battery string formed after step B5 according to an embodiment of the present invention;

[0035] Fig.12 is a schematic structural diagram of a semi-finished battery string pressed by a press after step B7 according to an embodiment of the present invention;

[0036] Fig.13 is a structural schematic diagram of placing a semi-finished battery string pressed by a press on a roller 9 according to an embodiment of the present invention;

[0037] Fig.14 It is a structural schematic diagram of placing a semi-finished battery string pressed by a press on a transmission belt according to an embodiment of the present invention.

[0038] Reference numerals:

[0039] 1-battery string; 100-battery cell; 200-first metal wire mesh; 210-first electrical connection part; 220-second electrical connection part; 201-first metal wire; 202-second metal wire; 300-second metal wire mesh; 310-third electrical connection part; 320-fourth electrical connection part; 301-third metal wire; 302-fourth metal wire; 400-bus bar; 500-conductive adhesive layer; 600-carrying film; 2-front adhesive film; 3-back adhesive film; 4-panel material; 5-back panel material; 6-release film; 7-press; 8-curing oven; 9-roller; 10-tray platform; 11-transmission belt. DETAILED DESCRIPTION

[0040] The existing busbar-free technology mainly includes two methods of current collection through welding strips or metal mesh.

[0041] When using welding ribbon for current collection, the welding ribbon and fine grid are alloyed. Due to the small diameter of the fine grid, the contact area between the welding ribbon and the fine grid is small, which is prone to grid breakage. In order to increase the reliability of welding ribbon, a contact (PAD) point can be added at the contact position between the battery cell and the welding ribbon, but the existence of the fine grid and PAD point leads to a high cost of metal slurry.

[0042] When a metal mesh is used for current collection, the metal mesh can be alloyed with a fine grid and fixed to the surface of the cell. In the process of laying the metal mesh, the metal mesh and the fine grid need to be precisely aligned, which requires higher process precision, resulting in higher equipment costs and lower product yields. In addition, when the metal mesh is directly set on the surface of the cell (no fine grid is required on the surface of the cell), the metal mesh is only fixed to the surface of the cell by bonding, which is not reliable and cannot ensure the contact between the metal mesh and the cell, affecting the current transmission efficiency.

[0043] In the case of a busbar-free cell with fine grids, in order to enhance the reliability of the welding strip or metal mesh, it is necessary to set more fine grids than the cell with a busbar. However, the large number of fine grids makes it impossible to reduce the cost of metal paste for preparing the grid lines, and the presence of fine grids also requires high process precision, resulting in low reliability of the cell. If the fine grids are removed, the metal wires or welding strips in the metal mesh extend in one direction in the cell, and the following problems will occur: 1. The current collection capacity is reduced; 2. The surface of the busbar-free cell without grid lines is directly exposed and prone to scratches; 3. The current-voltage characteristic curve (IV) test of the cell cannot be performed, and the efficiency distribution of the cell cannot be determined, and the cell cannot be sorted. It should be noted that during the IV test, the probe or wire of the IV test device needs to contact the busbar or fine grid of the battery to perform the IV test. In the absence of the busbar and fine grid, and the welding strip or metal mesh extends in one direction, the IV test cannot be performed.

[0044] In addition, for the busbar-less cells without fine grids, it is necessary to first print a positioning layer for positioning the metal mesh on the cell, and then lay the metal mesh. Therefore, in the process of laying the metal mesh, it is necessary to accurately align the metal mesh with the positioning layer, which undoubtedly requires higher process precision, resulting in higher equipment costs and lower product yield.

[0045] In order to protect the non-busbar cell and reduce scratches, a carrier film can be laid on the surface. The carrier film can also fix the welding strip or metal mesh. However, due to limitations such as process deviation, the coating effect on the edge of the cell is not good, and scratches will still appear on the edge of the cell. In addition, the fixation effect on the welding strip or metal mesh is not good, and the welding strip or metal mesh is prone to offset. When the cell is tested for electroluminescence (EL), the edge of the cell not covered by the carrier film is exposed, and the edge of the cell is prone to blackening.

[0046] In addition, adjacent cells in a cell string are connected in series via welding ribbons or metal meshes laid on the surface of the cells. The welding ribbons or metal meshes extend from the front side of one adjacent cell to the back side of another adjacent cell, which inevitably causes the welding ribbons or metal meshes in the middle of adjacent cells to bend. The bent part has greater stress, reducing the reliability of the photovoltaic module.

[0047] The following is a description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0048] It should be pointed out that the embodiments of the present invention and the technical features therein may be combined with each other without conflict.

[0049] It should be understood that in various embodiments of the present invention, the size of the sequence number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0050] It should be noted that the front side of the cell in the embodiment of the present invention refers to the side of the cell facing the sunlight or the side facing away from the sunlight when the cell is working, and correspondingly, the back side of the cell refers to the side facing away from the front side of the cell. As an example, when the front side of the cell refers to the side of the cell facing the sunlight when the cell is working, the back side of the cell refers to the side facing away from the sunlight when the cell is working; when the back side of the cell refers to the side of the cell facing away from the sunlight when the cell is working, the back side of the cell refers to the side of the cell facing the sunlight when the cell is working.

[0051] Figure 1 4 is a schematic diagram of the longitudinal cross-sectional structure of a battery string according to an embodiment of the present invention. Figure 2 is a top view of a battery string according to an embodiment of the present invention; it should be noted that, Figure 1 and Figure 2 The battery string structure including two adjacent battery cells is shown only as an example. In fact, the number of battery cells in the battery string can be set according to actual conditions, including but not limited to two.

[0052] like Figure 1 and Figure 2As shown, one aspect of an embodiment of the present invention provides a battery string 1, which mainly includes: a plurality of battery cells 100, wherein transparent conductive films (Transparent Conductive Oxide, TCO) are provided on the front and back of the battery cells 100. A first metal wire mesh 200 laid on the front of each of the battery cells 100 and electrically connected to the transparent conductive film on the front of the battery cells 100; a second metal wire mesh 300 laid on the back of each of the battery cells 100 and electrically connected to the back of the battery cells 100; and a plurality of bus bars 400.

[0053] The transparent conductive film has the properties of transparency and conductivity. When the TCO film is deposited on the surface of the cell 100, it can cooperate with the first metal mesh 200 and the second metal mesh 300 to enhance the current collection capability. The first metal mesh 200 and the second metal mesh 300 are electrically connected to the transparent conductive film for current collection.

[0054] The material of the first metal mesh 200 and the second metal mesh 300 may be tin-lead-bismuth alloy, but is not limited thereto.

[0055] For every two adjacent battery cells 100 , the first metal mesh 200 on one battery cell 100 and the second metal mesh 300 on another adjacent battery cell 100 are electrically connected to the same bus bar 400 , so as to connect a plurality of battery cells 100 in series.

[0056] The surface of the cell 100 of the embodiment of the present invention is not provided with a main grid, a fine grid and a PAD point, but the current is transmitted through a transparent conductive film laid on the surface of the cell 100 body, and the current is collected through a metal mesh, thereby reducing the cost of metal pastes such as silver paste. The first metal mesh 200 and the second metal mesh 300 are used to collect the current transmitted by the transparent conductive film. Therefore, the surface of the cell 100 of the embodiment of the present invention does not need to be provided with a welding strip, nor does it need to align the first metal mesh 200 or the second metal mesh 300 with the grid line, which greatly simplifies the preparation process of the cell string 1.

[0057] In addition, the embodiment of the present invention avoids the phenomenon that the metal wire mesh located between adjacent battery cells 100 is bent due to the use of metal wire mesh to connect adjacent battery cells 100 in series, by setting a bus bar 400 between adjacent battery cells 100, thereby solving the problem of reduced reliability of photovoltaic modules caused by excessive stress in the bent part.

[0058] In an optional embodiment, if Figure 3 As shown, the first metal wire mesh 200 includes: a first electrical connection portion 210 disposed corresponding to the transparent conductive film on the front side of the battery cell 100 and a second electrical connection portion 220 extending from the battery cell 100 .

[0059] The first electrical connection part 210 is attached to the transparent conductive film on the front of the battery for current collection. The second electrical connection part 220 is electrically connected to the bus bar 400 and connected to the second metal mesh 300 of the adjacent battery cell 100 through the bus bar 400.

[0060] Optionally, the width H of the second electrical connection portion 220 is 1 As an example, the width of the second electrical connection portion 220 may be 3 mm, 4 mm, 4.5 mm or 5 mm.

[0061] The bus bar 400 can be arranged in a variety of ways, including inclined arrangement, vertical arrangement, etc. As an example, when the second metal wire mesh 300 does not extend from the back of another battery cell 100 to between two adjacent battery cells 100 (i.e., does not include the fourth electrical connection portion 320), in order to realize the electrical connection between the first metal wire mesh 200 and the second metal wire mesh 300 through the bus bar 400, and to connect adjacent battery cells 100 in series, the bus bar 400 can be arranged obliquely below the second electrical connection portion 220, so that one end of the bus bar 400 is electrically connected to the second electrical connection portion 220, and the other end is connected to the second metal wire mesh 300 of the adjacent battery cell 100.

[0062] In an optional embodiment, if Figure 4 As shown, the second metal mesh 300 includes: a third electrical connection portion 310 arranged corresponding to the transparent conductive film on the back of the battery cell 100 and a fourth electrical connection portion 320 extending out of the battery cell 100 .

[0063] The third electrical connection part 310 is attached to the transparent conductive film on the back of the battery for current collection. The fourth electrical connection part 320 extending from the battery cell 100 is electrically connected to the bus bar 400 and connected to the first metal mesh 200 of the adjacent battery cell 100 through the bus bar 400.

[0064] Optionally, the width H of the fourth electrical connection portion 320 is 2 As an example, the width of the fourth electrical connection portion 320 may be 3 mm, 4 mm, 4.5 mm or 5 mm.

[0065] The bus bar 400 can be arranged in a variety of ways, including inclined arrangement, vertical arrangement, etc. As an example, when the first metal wire mesh 200 does not extend from the back of another battery cell 100 to between two adjacent battery cells 100 (i.e., does not include the second electrical connection portion 220), in order to realize the electrical connection between the first metal wire mesh 200 and the second metal wire mesh 300 through the bus bar 400, and to connect adjacent battery cells 100 in series, the bus bar 400 can be inclinedly arranged above the fourth electrical connection portion 320, so that one end of the bus bar 400 is electrically connected to the fourth electrical connection portion 320, and the other end is connected to the first metal wire mesh 200 of the adjacent battery cell 100.

[0066] Furthermore, if Figure 1 and Figure 5 As shown, for the structure in which the first metal wire mesh 200 includes the second electrical connection part 220 and the second metal wire mesh 300 includes the fourth electrical connection part 320, the second electrical connection part 220 and the fourth electrical connection part 320 corresponding to the same battery cell 100 extend in opposite directions; the bus bar 400 is located between each two adjacent battery cells 100.

[0067] In this case, the first metal mesh 200 located on the front side of the battery cell 100 includes both the first electrical connection portion 210 and the second electrical connection portion 220, and the second metal mesh 300 located on the back side of the battery cell 100 includes both the third electrical connection portion 310 and the fourth electrical connection portion 320. On a plane parallel to the arrangement direction of the battery cells 100 (i.e., a plane parallel to the first metal mesh 200 and the second metal mesh 300), the projections of the second electrical connection portion 220 and the fourth electrical connection portion 320 partially overlap, and the projection of the bus bar 400 is located in the partially overlapping projections of the second electrical connection portion 220 and the fourth electrical connection portion 320, so as to connect the second electrical connection portion 220 and the fourth electrical connection portion 320.

[0068] In this case, if Figure 1 As shown, the width of the bus bar 400 is smaller than the distance between adjacent battery cells 100. Preferably, the width H of the bus bar 400 is 3 As an example, the width of the bus bar 400 may be 1 mm, 1.1 mm, 1.25 mm, 1.4 mm, or 1.5 mm.

[0069] In an optional embodiment, if Figure 5As shown, the battery string 1 may further include a carrier film 600 disposed on the side of the first metal mesh 200 and / or the second metal mesh 300 away from the battery cell 100. In order to better fix the first metal mesh 200 and / or the second metal mesh 300, the first metal mesh 200 and / or the second metal mesh 300 are in close contact with the battery cell 100 to better achieve current transmission. In addition, by arranging the carrier film 600 on the surface of the battery cell 100, the carrier film 600 can protect the surface of the battery cell 100, reduce the possibility of scratching the battery cell 100 during the preparation process, and improve the yield rate of the battery cell 100.

[0070] As an example, the carrier film 600 may be disposed only on the side of the first metal mesh 200 away from the battery cell 100. In this case, the carrier film 600 is disposed only on the front side of the battery cell 100. As another example, the carrier film 600 may be disposed on the side of the second metal mesh 300 away from the battery cell 100. In this case, the carrier film 600 is disposed only on the back side of the battery cell 100. As another example, the carrier film 600 may be disposed on the side of the first metal mesh 200 away from the battery cell 100 and the side of the second metal mesh 300 away from the battery cell 100, respectively. In this case, the carrier film 600 is disposed on the front and back sides of each battery cell 100, and the carrier film 600 can protect both surfaces of the battery cell 100 at the same time.

[0071] Optionally, the carrier film 600 may be made of thermoplastic material or thermosetting material. Specifically, the carrier film 600 may be made of ethylene vinyl acetate copolymer (EVA), polyolefin elastomer (POE) or polyolefin (PO), but is not limited thereto.

[0072] In an optional embodiment, if Figure 6 As shown, the first metal wire mesh 200 includes a plurality of first metal wires 201 parallel to the first direction and a plurality of second metal wires 202 parallel to the second direction, and the first metal wires 201 and the second metal wires 202 are crossed to form a mesh structure; the second metal wire mesh 300 includes a plurality of third metal wires 301 parallel to the first direction and a plurality of fourth metal wires 302 parallel to the second direction, and the third metal wires 301 and the fourth metal wires 302 are crossed to form a mesh structure; wherein the first direction is perpendicular to the second direction.

[0073] The first direction may refer to the arrangement direction of the battery cell 100 , that is, the extension direction of the main grid when the battery cell 100 is provided with a main grid; the second direction may refer to a direction perpendicular to the arrangement direction of the battery cell 100 .

[0074] Furthermore, the first metal wire 201 and the third metal wire 301 can be arranged at equal intervals in the first direction, and the second metal wire 202 and the fourth metal wire 302 can be arranged at equal intervals in the second direction, so that the first metal wire 201 and the second metal wire 202 are evenly distributed in the first electrical connection part 210, and the third metal wire 301 and the fourth metal wire 302 are evenly distributed in the fourth electrical connection part 320, so as to better realize current collection and transmission.

[0075] In addition, the second electrical connection portion 220 and the fourth electrical connection portion 320 can transmit current through the bus bar 400, so the second electrical connection portion 220 may not be provided with the second metal wire 202, and the fourth electrical connection portion 320 may not be provided with the fourth metal wire 302. Optionally, the bus bar 400 between adjacent battery cells 100 may be parallel to the second direction, so that when overlooking the front side of the battery string 1, the bus bar 400 is perpendicular to the first metal wire 201 and the third metal wire 301.

[0076] Optionally, the number of the first metal wires 201 in each first metal wire mesh 200 may be 30 to 60, and the number of the second metal wires 202 may be 70 to 130. As an example, the number of the first metal wires 201 may be 30, 45, 50 or 60, and the number of the second metal wires 202 may be 70, 85, 100, 110 or 130, etc.

[0077] The number of the third metal wires 301 in each second metal wire mesh 300 may be 30 to 60, and the number of the fourth metal wires 302 may be 70 to 130. As an example, the number of the third metal wires 301 may be 30, 45, 55 or 60, and the number of the fourth metal wires 302 may be 70, 87, 100, 112 or 130, etc.

[0078] The wire diameters of the first metal wire 201, the second metal wire 202, the third metal wire 301 and the fourth metal wire 302 may be 0.5 μm to 5 μm. As an example, the wire diameters of the first metal wire 201, the second metal wire 202, the third metal wire 301 and the fourth metal wire 302 may be 0.5 μm, 1.0 μm, 2.5 μm, 3.5 μm or 5 μm.

[0079] It should be noted that the second metal mesh 300 has substantially the same structure as the first metal mesh 200 , and the only difference is that the fourth electrical connection portion 320 of the second metal mesh 300 extends in the opposite direction to the second electrical connection portion 220 of the first metal mesh 200 .

[0080] In an optional embodiment, if Figure 3 and Figure 4 As shown, conductive adhesive layers 500 are arranged on the surfaces of the first metal wire 201, the second metal wire 202, the third metal wire 301 and the fourth metal wire 302. The conductive adhesive layer 500 is made of a material with bonding and conductive properties, and can fix the metal mesh to the surface of the battery cell 100, so as to realize electrical connection between the metal mesh and the TCO film on the surface of the battery cell 100.

[0081] Optionally, the conductive adhesive layer 500 can be made of a conductive adhesive material or a conductive coating, wherein the conductive adhesive material can be a conductive glue, and the conductive coating can be a polyamide-based wire paint, but is not limited thereto.

[0082] Furthermore, a small amount of silver particles may be filled in the wire paint coating to improve the conductive properties of the conductive coating. The volume percentage of the silver particles in the wire paint coating may be 8% to 12%. As an example, the volume percentage of the silver particles in the wire paint coating may be 8%, 9%, 10%, 11%, or 12%.

[0083] The conductive adhesive layer 500 is prepared by using a material with bonding and conductive properties. On the one hand, the metal wire mesh can be firmly fixed to the surface of the battery cell 100 to prevent the metal wire mesh from moving. On the other hand, the conductive adhesive layer 500 can also enhance the electrical conductivity of the TCO film and the metal wire mesh and improve the current transmission efficiency.

[0084] According to the battery string 1 of the embodiment of the present invention, a first metal mesh 200 is laid on the front side of a battery cell 100 provided with a transparent conductive film, and a second metal mesh 300 is laid on the back side. The first metal mesh 200 and the second metal mesh 300 are electrically connected to the transparent conductive film. It is unnecessary to set grid lines and welding strips on the surface of the battery cell 100, so current can be collected and transmitted, thereby reducing the cost of metal slurry.

[0085] By using a bus bar 400 to connect the first metal wire mesh 200 of one battery cell 100 and the second metal wire mesh 300 of the other battery cell 100 of two adjacent battery cells 100, the battery cells 100 are connected in series to form a battery string 1, which avoids the bending of the part of the metal wire mesh located between the two battery cells 100 caused by connecting two adjacent battery cells 100 through the same piece of metal wire mesh, solves the problem of excessive stress in this part reducing the reliability of the battery string 1, and improves the structural stability of the battery string 1.

[0086] In addition, the first metal wire mesh 200 includes a first metal wire 201 parallel to the first direction and a second metal wire 202 parallel to the second direction, and the second metal wire mesh 300 includes a third metal wire 301 parallel to the first direction and a fourth metal wire 302 parallel to the second direction, so that the first metal wire 201 and the second metal wire 202 extend in two directions perpendicular to each other, respectively, and the third metal wire 301 and the fourth metal wire 302 extend in two directions perpendicular to each other, respectively. The first metal wire mesh 200 and the second metal wire mesh 300 are in a mesh structure, which improves the current collection and transmission capability. Neither a main grid nor a fine grid is required to be set on the surface of the battery cell 100, which solves the problem of aligning the metal wire mesh with the fine grid during the preparation of the battery string 1. Moreover, by setting the first metal wire mesh 200 and the second metal wire mesh 300 of the mesh structure, the probe can be connected to the metal wire mesh extending in different directions during the IV test of the battery cell 100, which solves the problem that the battery cell 100 without a grid line cannot pass the IV test for battery sorting.

[0087] like Figure 7 As shown, one aspect of an embodiment of the present invention provides a photovoltaic assembly, including a battery string 1 according to an embodiment of the present invention.

[0088] In an optional embodiment, the photovoltaic module may further include a front adhesive film 2 laid on the front side of the battery string 1, a rear adhesive film 3 laid on the back side of the battery string 1, a panel material 4 located on the side of the front adhesive film 2 away from the battery string 1, and a back panel material 5 located on the side of the rear adhesive film 3 away from the battery string 1.

[0089] Specifically, the photovoltaic module includes, in order, the panel material 4, the front adhesive film 2, the battery string 1, the rear adhesive film 3, and the backboard material 5 in the direction away from the sunlight when it is working.

[0090] According to the photovoltaic module of the embodiment of the present invention, by adopting a battery string 1 provided with a first metal wire mesh 200 and a second metal wire mesh 300 electrically connected to a transparent conductive film, current can be collected and transmitted without setting grid lines and welding strips on the surface of the battery cell 100, thereby reducing the metal slurry cost for preparing the photovoltaic module.

[0091] In the battery string 1, a bus bar 400 is used to connect the first metal mesh 200 of one battery cell 100 and the second metal mesh 300 of the other battery cell 100 in two adjacent battery cells 100, thereby avoiding the bending of the metal mesh located between the two battery cells 100 due to connecting the two adjacent battery cells 100 through the same metal mesh, solving the problem of excessive stress in this part reducing the reliability of the photovoltaic module, and improving the structural stability of the photovoltaic module. At the same time, there is no need to align the first metal mesh 200 of one battery cell 100 and the second metal mesh 300 of the other battery cell 100 in the adjacent battery cells 100, so that the precision requirements during the preparation of the battery string 1 are relatively small.

[0092] In addition, the first metal wire mesh 200 includes a first metal wire 201 parallel to the first direction and a second metal wire 202 parallel to the second direction, and the second metal wire mesh 300 includes a third metal wire 301 parallel to the first direction and a fourth metal wire 302 parallel to the second direction, so that the first metal wire 201 and the second metal wire 202 extend in two directions perpendicular to each other, respectively, and the third metal wire 301 and the fourth metal wire 302 extend in two directions perpendicular to each other, respectively. The first metal wire mesh 200 and the second metal wire mesh 300 are in a mesh structure, which improves the current collection and transmission capability. Neither a main grid nor a fine grid is required to be set on the surface of the battery cell 100, which solves the problem of aligning the metal wire mesh with the fine grid during the preparation of the battery string 1. Moreover, by setting the first metal wire mesh 200 and the second metal wire mesh 300 of the mesh structure, the probe can be connected to the metal wire mesh extending in different directions during the IV test of the battery cell 100, which solves the problem that the battery cell 100 without a grid line cannot pass the IV test for battery sorting, and improves the yield rate of the photovoltaic module.

[0093] like Figure 8 As shown, another aspect of an embodiment of the present invention provides a method for preparing a battery string 1, comprising:

[0094] Step A1, laying the battery cell 100 on the second metal wire mesh 300 so that the back side of the battery cell 100 contacts the second metal wire mesh 300;

[0095] Wherein, the front and back sides of the cell 100 are both provided with transparent conductive films, and no grid lines are provided;

[0096] Step A2: laying a first metal mesh 200 on the front side of the battery cell 100;

[0097] Step A3, pressing and curing the battery cell 100 on which the first metal wire mesh 200 and the second metal wire mesh 300 are laid;

[0098] Step A4, testing and screening the cured battery cells;

[0099] Specifically, the cured cells are subjected to IV testing, and their performance is evaluated based on the current-voltage characteristic curve obtained from the test, and they are classified into different grades based on performance parameters. Then, the cells of different grades are subjected to electroluminescent (EL) testing. The cells that have passed the EL test are screened to remove defective cells.

[0100] Step A5: For adjacent screened battery cells, use the bus bar 400 to electrically connect the second electrical connection part 220 of the first metal wire mesh 200 of one of the above-mentioned screened battery cells, and to electrically connect the bus bar 400 to the fourth electrical connection part 320 of the second metal wire mesh 300 of another above-mentioned screened battery cell.

[0101] In an optional embodiment, before the above step A1, the above method further includes:

[0102] Step A0, stacking the release film 6 and the carrier film 600 to form a stacked film layer, and laying the second metal wire mesh 300 on the stacked film layer;

[0103] Step A2 also includes: laying the first metal wire mesh 200 on the laminated film layer.

[0104] For the battery string 1 including the carrier film 600, the carrier film 600 can be provided on the front and back of each battery cell 100. In order to prevent the carrier film 600 from shrinking during the subsequent preparation process and causing the edge of the battery cell 100 to be exposed, a release film 6 with a certain rigidity can be laminated on the side of the carrier film 600 away from the battery cell 100. The release film 6 can also assist in lamination, so that the lamination effect of the carrier film 600, the metal mesh and the battery cell 100 is better.

[0105] The release film 6 may be made of polypropylene (PP) or polyethylene terephthalate (PET), but is not limited thereto.

[0106] Specifically, step A0 may include: stacking the release film 6 and the carrier film 600 to form a stacked film layer. If the size of the stacked film layer is inconsistent with the size of the battery cell 100, the stacked film layer may be cut to make its size the same as the battery cell 100. Then, the second metal wire mesh 300 is laid on the cut stacked film layer. Then, step A1 is performed.

[0107] Step A2 may include: when laying the first metal mesh 200, the first metal mesh 200 may be laid on the above-mentioned laminated film layer first, flipped over, and then laid on the front side of the battery cell 100, so that the first metal mesh 200 is electrically connected to the transparent conductive film on the front side of the battery cell 100.

[0108] Furthermore, for a battery cell provided with a laminated film layer, the above step A3 further includes: after the lamination and curing is completed, removing the release film 6 provided on the front and back sides of the above battery cell.

[0109] Specifically, step A3 includes: placing a battery cell provided with a laminated film layer on a tray platform 10 so that the back side is evenly stressed to prevent cracking. Placing a press 7 on the front side of the battery cell provided with a laminated film layer, and pressing and fixing the laminated film layer, the first metal wire mesh 200, the battery cell 100, the second metal wire mesh 300, and the laminated film layer by the press 7. After pressing and fixing, the pressed and fixed material is sent to a curing furnace 8 for curing. After curing is completed, the press 7 on the front side of the battery cell 100 is removed, and the release film 6 on the front side of the battery cell 100 is removed together with the press 7, and the tray platform 10 on the back side of the battery cell 100 is removed, and the release film 6 on the back side of the battery cell 100 is removed together with the tray platform 10.

[0110] It should be noted that in step A0, the formed laminated film layer can be placed directly on the tray platform 10, and then the second metal wire mesh 300 can be laid on the laminated film layer, so that the laying of the battery cell 100, the laying of the first metal wire mesh 200 provided with the laminated film layer, and the placement of the press 7 are all carried out on the tray platform 10.

[0111] Optionally, during the curing process, the length of the curing oven 8 may be 3m-5m; the curing temperature may vary with the melting point of the carrier film 600, and may generally be 100°C-140°C; and the curing time may be about 20s. As an example, the length of the curing oven 8 may be 3m, 3.5m, 4m or 5m, etc.; and the curing temperature may be 100°C, 110°C, 120°C, 130°C or 140°C, etc.

[0112] In an optional embodiment, the method further comprises: printing a conductive adhesive material at intervals on each metal wire of the metal wire mesh to form a conductive adhesive layer 500 .

[0113] In order to better fix the metal mesh to the surface of the battery cell 100 , in step A0 and step A2 , a conductive adhesive material may be printed on each metal wire of the metal mesh at intervals to form a conductive adhesive layer 500 .

[0114] Specifically, step A0 may also include: after laying the second metal mesh 300 on the laminated film layer, the conductive adhesive material can be printed at equal intervals on each metal wire (the third metal wire 301 and the fourth metal wire 302) of the second metal mesh 300 by screen printing, and a conductive adhesive layer 500 is formed on the surface of each metal wire. When the battery cell 100 is laid on the second metal mesh 300, the second metal mesh 300 can be preliminarily fixed to the back of the battery cell 100 by the viscosity of the conductive adhesive layer 500.

[0115] Step A2 may also include: after laying the first metal mesh 200 on the above-mentioned laminated film layer, before laying the first metal mesh 200 provided with the laminated film layer on the front side of the battery cell 100, a conductive adhesive material can be printed at equal intervals on each metal wire (the first metal wire 201 and the second metal wire 202) of the first metal mesh 200 by screen printing, and a conductive adhesive layer 500 is formed on the surface of each metal wire. When the first metal mesh 200 provided with the laminated film layer is laid on the front side of the battery cell 100, the first metal mesh 200 can be preliminarily fixed to the back side of the battery cell 100 by the viscosity of the conductive adhesive layer 500.

[0116] Optionally, the printing width of the conductive adhesive material can be adjusted according to the wire diameter of the metal wire mesh. Each metal wire includes a plurality of sections of conductive adhesive layer 500, wherein the length of each section of conductive adhesive layer 500 can be 2 mm to 3 mm. As an example, the length of each section of conductive adhesive layer 500 can be 2 mm, 2.5 mm, or 3 mm.

[0117] Furthermore, when printing the conductive adhesive material, the edge of the laminated film layer can be used for positioning so as to better determine the printing position, further reducing the precision requirement for preparing the battery string 1 .

[0118] After lamination and curing, the curing temperature enhances the viscosity of the conductive adhesive layer 500 , so that the second metal mesh 300 , the first metal mesh 200 and the battery cell 100 are firmly bonded, thereby improving the current collection capacity of the metal mesh, reducing contact resistance, and facilitating subsequent testing and screening of the battery cell 100 .

[0119] In an optional embodiment, the above method further includes:

[0120] Conductive paint is sprayed on each metal wire of the metal wire mesh at intervals to form a conductive coating.

[0121] In order to better fix the metal mesh to the surface of the battery cell 100 , before step A0 , conductive paint may be sprayed on each metal wire of the metal mesh at intervals to form a conductive adhesive layer 500 .

[0122] Specifically, during step A0, the first metal wire 201 and the second metal wire 202 need to be cross-fixed to form the first metal mesh 200, and the third metal wire 301 and the fourth metal wire 302 need to be cross-fixed to form the second metal mesh 300. After the first metal mesh 200 and the second metal mesh 300 are prepared, a conductive coating is sprayed at equal intervals on each metal wire of the first metal mesh 200 and the second metal mesh 300 using a spraying process to form a conductive adhesive layer 500. The first metal wire 201 and the second metal wire 202 are vertically arranged, and the third metal wire 301 and the fourth metal wire 302 are vertically arranged.

[0123] After lamination and curing, the curing temperature enhances the viscosity of the conductive adhesive layer 500 , so that the second metal mesh 300 , the first metal mesh 200 and the battery cell 100 are firmly bonded, thereby improving the current collection capacity of the metal mesh, reducing contact resistance, and facilitating subsequent testing and screening of the battery cell 100 .

[0124] Compared with the method of printing the conductive adhesive material on the surface of the metal mesh, the method of spraying the conductive coating can simplify the preparation process of the battery string 1, and the spraying method can reduce the material consumption, save costs, and form a more uniform conductive adhesive layer 500.

[0125] The preparation method of the battery string 1 is further described below through a specific embodiment:

[0126] like Fig. 9 As shown, the method for preparing the battery string 1 of the embodiment of the present invention includes steps B1 to B10:

[0127] Step B1, a plurality of first metal wires 201 parallel to the first direction and a plurality of second metal wires 202 parallel to the second direction are crossed to form a mesh structure, so as to prepare a first metal wire mesh 200; a plurality of third metal wires 301 parallel to the first direction and a plurality of fourth metal wires 302 parallel to the second direction are crossed to form a mesh structure, so as to prepare a second metal wire mesh 300;

[0128] Step B2: spraying conductive paint on each metal wire of the first metal wire mesh 200 and the second metal wire mesh 300 at equal intervals by using a spraying process to form a conductive adhesive layer 500 on the surface of each metal wire of the first metal wire mesh 200 and the second metal wire mesh 300;

[0129] Step B3, stacking the release film 6 and the carrier film 600 to form a stacked film layer, and cutting the stacked film layer according to the size of the battery cell 100 so that the size is the same as that of the battery cell 100;

[0130] Step B4: Fig.10As shown, the second metal wire mesh 300 is laid on the cut laminated film layer; the first metal wire mesh 200 is laid on the cut laminated film layer;

[0131] Step B5: Fig.11 As shown, a second metal wire mesh 300 provided with a laminated film layer is placed on the tray platform 10, and a battery cell 100 is laid on the second metal wire mesh 300 provided with a laminated film layer, so that the back side of the battery cell 100 contacts the second metal wire mesh 300;

[0132] Wherein, the front and back sides of the cell 100 are both provided with transparent conductive films, and no grid lines are provided;

[0133] Step B6: Laying a first metal wire mesh 200 provided with a laminated film layer on the front side of the battery cell 100;

[0134] Step B7: Fig.12 As shown, the press 7 is placed on the front side of the battery cell 100 provided with the laminated film layer, and the laminated film layer, the first metal wire mesh 200, the battery cell 100, the second metal wire mesh 300, and the laminated film layer are pressed and fixed by the press 7;

[0135] Step B8, after being pressed and fixed, the semi-finished battery string pressed by the press 7 is placed in the transmission device of the curing furnace 8 and sent into the curing furnace 8 for curing;

[0136] Specifically, the transmission device can be a roller 9 or a transmission belt 11. Fig.13 As shown, when the transmission device is a roller 9, the tray platform 10 on which the semi-finished battery string pressed by the press 7 is placed can be placed on the roller 9, and the semi-finished battery string pressed by the press 7 can be sent to the curing furnace 8 through the rotation of the roller 9; Fig.14 As shown, when the transmission device is a transmission belt 11 , the semi-finished battery string pressed by the press 7 can be directly placed on the transmission belt 11 , so that the release film 6 on the back of the battery cell 100 directly contacts the transmission belt 11 .

[0137] After curing is completed, when the transmission device is a roller 9, the press 7 on the front of the battery cell 100 is removed, and the release film 6 on the front of the battery cell 100 is removed together with the press 7, and the tray platform 10 on the back of the battery cell 100 is removed, and the release film 6 on the back of the battery cell 100 is removed together with the tray platform 10; when the transmission device is a transmission belt 11, the press 7 on the front of the battery cell 100 is removed, and the release film 6 on the front of the battery cell 100 is removed together with the press 7, and the battery cell 100 is removed from the transmission belt 11, and the release film 6 on the back of the battery cell 100 is adsorbed by the transmission belt 11 and removed.

[0138] Step B9, performing IV testing, sorting, EL testing and screening on the cured cells to remove defective cells;

[0139] Step B10, arrange the screened battery cells along the first direction, and for adjacent screened battery cells, use a bus bar 400 to electrically connect the second electrical connection portion 220 of the first metal wire mesh 200 of one of the above-mentioned screened battery cells, and electrically connect them to the fourth electrical connection portion 320 of the second metal wire mesh 300 of another of the above-mentioned screened battery cells, to obtain a battery string 1.

[0140] According to the preparation method of the battery string 1 of the embodiment of the present invention, by laying a first metal wire mesh 200 having a first metal wire 201 and a second metal wire 202 extending in different directions and a second metal wire mesh 300 having a third metal wire 301 and a fourth metal wire 302 extending in different directions on the battery cell 100, even if no grid lines are set on the surface of the battery cell 100, IV testing can also be performed through the metal wire mesh, and there is no need to align the metal wire mesh with the grid lines when laying the metal wire mesh.

[0141] In addition, by covering the carrier film 600 with a rigid release film 6, the carrier film 600 can be prevented from shrinking during the curing process, which may cause the battery edge to be exposed, thereby reducing the possibility of scratching the battery.

[0142] According to another aspect of an embodiment of the present invention, a method for preparing a photovoltaic module is provided, comprising: preparing a battery string 1; after preparing the battery string 1, stacking a panel material 4, a front adhesive film 2, the battery string 1, a rear adhesive film 3 and a backboard material 5 in sequence, performing lamination, framing, curing, cleaning, etc., to prepare the photovoltaic module of the embodiment of the present invention.

[0143] The preparation of the battery string 1 adopts the preparation method of the battery string 1 of the embodiment of the present invention, which will not be described in detail here.

[0144] According to the method for preparing a photovoltaic module according to an embodiment of the present invention, by laying a first metal wire mesh 200 having a first metal wire 201 and a second metal wire 202 extending in different directions and a second metal wire mesh 300 having a third metal wire 301 and a fourth metal wire 302 extending in different directions on a battery cell 100, an IV test can be performed through the metal wire mesh even when no grid lines are set on the surface of the battery cell 100, and there is no need to align the metal wire mesh with the grid lines when laying the metal wire mesh.

[0145] In addition, by covering the carrier film 600 with a rigid release film 6, the carrier film 600 can be prevented from shrinking during the curing process, which may cause the battery edge to be exposed, thereby reducing the possibility of scratching the battery.

[0146] In summary, the embodiments of the present invention provide the following technical solutions:

[0147] Technical solution 1, a battery string, comprising:

[0148] A plurality of battery cells 100, wherein the front and back sides of the battery cells 100 are both provided with transparent conductive films;

[0149] A first metal mesh 200 laid on the front of each of the battery cells 100 and electrically connected to the transparent conductive film on the front of the battery cell 100;

[0150] A second metal mesh 300 laid on the back side of each of the battery cells 100 and electrically connected to the back side of the battery cells 100;

[0151] and a plurality of bus bars 400 ; for each two adjacent battery cells 100 , the first metal wire mesh 200 on one battery cell 100 and the second metal wire mesh 300 on another adjacent battery cell 100 are electrically connected to the same bus bar 400 to connect a plurality of battery cells 100 in series.

[0152] Technical solution 2: The battery string according to technical solution 1,

[0153] The first metal wire mesh 200 includes: a first electrical connection portion 210 disposed corresponding to the transparent conductive film on the front side of the battery cell 100 and a second electrical connection portion 220 extending from the battery cell 100;

[0154] The second electrical connection portion 220 is electrically connected to the bus bar 400 .

[0155] Technical solution 3: The battery string according to technical solution 1 or 2,

[0156] The second metal wire mesh 300 includes: a third electrical connection portion 310 disposed corresponding to the transparent conductive film on the back of the battery cell 100 and a fourth electrical connection portion 320 extending from the battery cell 100;

[0157] The fourth electrical connection portion 320 of the battery cell 100 is electrically connected to the bus bar 400 .

[0158] Technical solution 4: The battery string according to technical solution 3,

[0159] With respect to the structure in which the first metal wire mesh 200 includes the second electrical connection portion 220 and the second metal wire mesh 300 includes the fourth electrical connection portion 320,

[0160] The second electrical connection portion 220 and the fourth electrical connection portion 320 corresponding to the same battery cell 100 extend in opposite directions;

[0161] The bus bar 400 is located between every two adjacent battery cells 100 .

[0162] Technical solution 5. The battery string according to technical solution 1 further includes:

[0163] A carrier film 600 is disposed on a side of the first metal mesh 200 and / or the second metal mesh 300 away from the battery cell 100 .

[0164] Technical solution 6: The battery string according to technical solution 1,

[0165] The first metal wire mesh 200 includes a plurality of first metal wires 201 parallel to a first direction and a plurality of second metal wires 202 parallel to a second direction, and the first metal wires 201 and the second metal wires 202 are crossed to form a mesh structure;

[0166] The second metal wire mesh 300 includes a plurality of third metal wires 301 parallel to the first direction and a plurality of fourth metal wires 302 parallel to the second direction, and the third metal wires 301 and the fourth metal wires 302 are crossed to form a mesh structure;

[0167] The first direction is perpendicular to the second direction.

[0168] Technical solution 7: The battery string according to technical solution 6,

[0169] Conductive adhesive layers 500 are disposed on the surfaces of the first metal wire 201, the second metal wire 202, the third metal wire 301 and the fourth metal wire 302 at intervals;

[0170] and / or,

[0171] The first direction is parallel to the arrangement direction of the battery cells 100;

[0172] The number of the first metal wires 201 and the third metal wires 301 is 30 to 60;

[0173] The number of the second metal wires 202 and the fourth metal wires 302 is 70 to 130;

[0174] and / or,

[0175] The wire diameters of the first metal wire 201 , the second metal wire 202 , the third metal wire 301 and the fourth metal wire 302 are in the range of 0.5 μm to 5 μm.

[0176] Technical solution 8. The battery string according to technical solution 1 or 2,

[0177] In the case where the first metal wire mesh 200 includes the second electrical connection portion 220, the width of the second electrical connection portion 220 is 3 mm to 5 mm;

[0178] and / or,

[0179] The width of the bus bar 400 is 1 mm to 1.5 mm.

[0180] Technical solution 9: The battery string according to technical solution 3,

[0181] The width of the fourth electrical connection portion 320 is 3 mm to 5 mm.

[0182] Technical solution 10. A photovoltaic module, comprising a battery string 1 as described in any one of technical solutions 1-9.

[0183] Technical solution 11, a method for preparing a battery string, comprising:

[0184] Step A1, laying the battery cell 100 on the second metal wire mesh 300 so that the back side of the battery cell 100 is in contact with the second metal wire mesh 300;

[0185] Step A2, laying a first metal wire mesh 200 on the front side of the battery cell 100;

[0186] Step A3, pressing and curing the battery cell 100 on which the first metal wire mesh 200 and the second metal wire mesh 300 are laid;

[0187] Step A4: testing and screening the cured battery cells 100;

[0188] Step A5: For adjacent screened battery cells 100, use a bus bar 400 to electrically connect the second electrical connection portion 220 of the first metal wire mesh 200 of one of the screened battery cells 100, and to electrically connect the bus bar 400 to the fourth electrical connection portion 320 of the second metal wire mesh 300 of another screened battery cell 100.

[0189] Technical solution 12. A method for preparing a battery string according to technical solution 11,

[0190] Before step A1, the method further includes:

[0191] Step A0, stacking the release film 6 and the carrier film 600 to form a stacked film layer, and laying the second metal wire mesh 300 on the stacked film layer;

[0192] Step A2 also includes: laying the first metal wire mesh 200 on the laminated film layer.

[0193] Technical solution 13. A method for preparing a battery string according to technical solution 12,

[0194] The step A3 further comprises:

[0195] After the lamination and curing are completed, the release films 6 disposed on the front and back sides of the battery cell 100 are removed.

[0196] Technical solution 14. The method for preparing a battery string according to technical solution 11, further comprising:

[0197] Printing a conductive adhesive material at intervals on each metal wire of the metal wire mesh to form a conductive adhesive layer 500;

[0198] or,

[0199] Conductive paint is sprayed onto each metal wire of the metal mesh at intervals to form a conductive adhesive layer 500 .

[0200] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A battery string, characterized in that: include: A plurality of battery cells (100), wherein the front and back sides of the battery cells (100) are both provided with transparent conductive films; A first metal wire mesh (200) laid on the front side of each battery cell (100) and electrically connected to the transparent conductive film on the front side of the battery cell (100); A second metal wire mesh (300) laid on the back side of each battery cell (100) and electrically connected to the back side of the battery cell (100); and a plurality of bus bars (400); for each two adjacent battery cells (100), a first metal wire mesh (200) on one battery cell (100) and a second metal wire mesh (300) on another adjacent battery cell (100) are electrically connected to the same bus bar (400) to connect the plurality of battery cells (100) in series.

2. The battery string according to claim 1, characterized in that: The first metal wire mesh (200) comprises: a first electrical connection portion (210) arranged corresponding to the transparent conductive film on the front side of the battery cell (100) and a second electrical connection portion (220) extending out of the battery cell (100); The second electrical connection portion (220) is electrically connected to the bus bar (400).

3. The battery string according to claim 1 or 2, characterized in that: The second metal wire mesh (300) comprises: a third electrical connection portion (310) arranged corresponding to the transparent conductive film on the back side of the battery cell (100) and a fourth electrical connection portion (320) extending out of the battery cell (100); The fourth electrical connection portion (320) of the battery cell (100) is electrically connected to the bus bar (400).

4. The battery string according to claim 3, characterized in that: With respect to the structure in which the first metal wire mesh (200) includes the second electrical connection portion (220) and the second metal wire mesh (300) includes the fourth electrical connection portion (320), The second electrical connection portion (220) and the fourth electrical connection portion (320) corresponding to the same battery cell (100) extend in opposite directions; The bus bar (400) is located between every two adjacent battery cells (100).

5. The battery string according to claim 1, characterized in that: Also includes: A carrier film (600) disposed on a side of the first metal wire mesh (200) and / or the second metal wire mesh (300) away from the battery cell (100).

6. The battery string according to claim 1, characterized in that: The first metal wire mesh (200) comprises a plurality of first metal wires (201) parallel to a first direction and a plurality of second metal wires (202) parallel to a second direction, the first metal wires (201) and the second metal wires (202) intersecting to form a mesh structure; The second metal wire mesh (300) comprises a plurality of third metal wires (301) parallel to the first direction and a plurality of fourth metal wires (302) parallel to the second direction, wherein the third metal wires (301) and the fourth metal wires (302) cross to form a mesh structure; The first direction is perpendicular to the second direction.

7. The battery string according to claim 6, characterized in that: Conductive adhesive layers (500) are arranged at intervals on the surfaces of the first metal wire (201), the second metal wire (202), the third metal wire (301) and the fourth metal wire (302); and / or, The first direction is parallel to the arrangement direction of the battery cells (100); The number of the first metal wires (201) and the third metal wires (301) is 30 to 60; The number of the second metal wires (202) and the fourth metal wires (302) is 70 to 130; and / or, The wire diameters of the first metal wire (201), the second metal wire (202), the third metal wire (301) and the fourth metal wire (302) are between 0.5 μm and 5 μm.

8. The battery string according to claim 1 or 2, characterized in that: When the first metal wire mesh (200) comprises a second electrical connection portion (220), the width of the second electrical connection portion (220) is 3 mm to 5 mm; and / or, The bus bar (400) has a width of 1 mm to 1.5 mm.

9. A photovoltaic module, characterized in that: Comprising a battery string (1) as described in any one of claims 1 to 8.

10. A method for preparing a battery string, characterized in that: include: Step A1: laying a battery cell (100) on a second metal wire mesh (300) so that the back side of the battery cell (100) is in contact with the second metal wire mesh (300); Step A2: laying a first metal wire mesh (200) on the front surface of the battery cell (100); Step A3, pressing and curing the battery cell (100) on which the first metal wire mesh (200) and the second metal wire mesh (300) are laid; Step A4, testing and screening the cured battery cell (100); Step A5: For adjacent screened battery cells (100), a bus bar (400) is used to electrically connect the second electrical connection portion (220) of the first metal wire mesh (200) of one of the screened battery cells (100), and to electrically connect the bus bar (400) to the fourth electrical connection portion (320) of the second metal wire mesh (300) of another of the screened battery cells (100).

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