Main-grid-free battery piece, battery string and photovoltaic module

Abstract

The embodiment of the utility model relates to the field of photovoltaic cells, and provides a main-grid-free battery piece, a battery string and a photovoltaic module, the main-grid-free battery piece comprises a battery substrate, a welding strip and a fixing structure, at least one surface of the battery substrate is provided with bonding areas and a film covering area, the bonding areas are located at the two ends of the battery substrate in the width direction, and the film covering area is located at the two ends of the battery substrate in the width direction. The number of the welding strips is at least one, the multiple welding strips extend in the width direction of the battery substrate, the fixing structure comprises a colloid and a film body, the colloid is arranged in the bonding area and used for fixing the parts, located in the bonding area, of the welding strips to the battery substrate, and the film body is configured to have viscidity and used for fixing the parts, located in the bonding area, of the welding strips to the battery substrate. And the film body at least partially covers the film covering area, so that the part, positioned in the film covering area, of the welding strip is fixed on the battery substrate. According to the invention, sheet disassembly and repair can be directly carried out in the bonding area without film tearing, so that the success rate of one-time repair and the yield of laminated assemblies can be improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic cells, and in particular to a main grid-free cell sheet, a cell string and a photovoltaic module. Background Art

[0002] At present, OBB (busbarless) technology is considered to be one of the best options for achieving cost reduction and efficiency improvement. Busbarless batteries use welding strips to directly connect fine grids to collect current and realize battery interconnection. Specifically, in the metal electrode screen printing process, the fine grid is screen-printed, but the main grid is not printed; in the assembly process, multiple metal wire welding strips perpendicular to the fine grid are covered on it, and the conventional silver main grid and fine grid are replaced with thinner and denser composite metal wires to form an interwoven conductive grid structure, followed by welding, lamination and other processes.

[0003] In the related art, the welding ribbon is usually fixed on the busbar-free cell by laminating to realize the interconnection of the busbar-free cell. That is, the welding ribbon is pressed and adhered to the front / back side of the cell by using a carrier film to connect in series, and then the welding ribbon and the cell fine grid are alloyed by lamination at high temperature.

[0004] However, the inventors realized that since the spacing between battery cells is usually small, when repairing the battery cells, the carrier film needs to be lifted up to cut the soldering tape. However, since the carrier film has a strong adhesive force after hot melting, it is not easy to tear open, which brings difficulties to the repair. Moreover, since the carrier film basically completely covers the soldering tapes at the heads and tails of the battery cells, the overlap space reserved for the battery cells is small, and the carrier film is easily burned when welding the soldering tape, further increasing the difficulty of repair. Utility Model Content

[0005] One or more embodiments of the present application provide a busbarless cell, a cell string and a photovoltaic module to solve or at least partially alleviate the problem of difficulty in rework caused by fixing welding strips by coating the entire busbarless cell in the related art.

[0006] In a first aspect of the present application, a busbar-free solar cell is provided, which adopts the following technical solution:

[0007] A busbar-free battery cell comprises: a battery substrate, at least one surface of which is provided with a bonding area and a coating area, wherein the bonding area is located at an end of the battery substrate in a width direction;

[0008] A welding strip, at least one welding strip is provided, and the welding strip extends along the width direction of the battery substrate;

[0009] A fixing structure, wherein the fixing structure comprises a colloid and a film, wherein the colloid is arranged in the bonding area, and the colloid is used to fix the portion of the solder strip located in the bonding area to the battery substrate, and the film is constructed to be sticky, and the film at least partially covers the coating area, so that the portion of the solder strip located in the coating area is fixed to the battery substrate.

[0010] By adopting the above technical scheme, the welding tape is fixed by two methods, namely, colloid bonding and film bonding. On the one hand, the fixing effect of the welding tape is better than that of the single method of using only film, and the cost is better than that of the solution of using only colloid. On the other hand, when the battery cell is repaired, since the welding tape in the bonding area is not covered by the film body, there is no need to lift the film body to cut the welding tape. Compared with the conventional film covering method, there is no need to tear the film when changing the cell, and there will be no adverse conditions caused by secondary film covering, which is conducive to the disassembly, overlapping and other repair operations between battery cells, and improves the success rate of one-time repair and the yield rate of component lamination.

[0011] In one of the embodiments, on the same surface of the battery substrate, there is a first distance between an end of the colloid away from the coating area and an edge of the battery substrate.

[0012] In one embodiment, the first distance is 0-10 mm.

[0013] In one embodiment, the film covers a portion of the bonding area.

[0014] In one embodiment, the width of the region where the film covers the bonding area is less than or equal to 2 mm.

[0015] In one embodiment, two sides of the film body parallel to the welding strip extend beyond the welding strips at two ends by a second distance.

[0016] In one embodiment, the second distance is 2-10 mm.

[0017] In one of the embodiments, the bonding area and the coating area are provided on the back side of the battery substrate.

[0018] In one embodiment, the bonding area is located at one end of the battery substrate in the width direction, and the coating area is located at the remaining area in the width direction of the battery substrate.

[0019] In one embodiment, the bonding area is located at two ends of the battery substrate in the width direction, and the coating area is located between the bonding areas at the two ends.

[0020] In one embodiment, the bonding area includes a first bonding area and a second bonding area; the width of the first bonding area is 1 / 10-1 / 5 of the width of the battery substrate, and / or the width of the second bonding area is 1 / 10-1 / 5 of the width of the battery substrate.

[0021] In one embodiment, the width of the coating area is 2 / 5-4 / 5 of the width of the battery substrate.

[0022] In one embodiment, the colloid comprises an adhesive tape, and the adhesive tape extends along the width direction of the battery substrate.

[0023] In one embodiment, the colloid includes a dotted colloid, and a plurality of the dotted colloids are spaced apart along the width direction of the battery substrate.

[0024] In a second aspect of the present application, a battery string is provided, which adopts the following technical solution:

[0025] A battery string, characterized in that it includes the busbar-free battery cell as described in any one of the above items, and the welding strips are sequentially connected to the front and back sides of adjacent busbar-free battery cells.

[0026] A battery string, characterized in that it includes the busbar-free battery cell as described in any one of the above items, and the welding strips are sequentially connected to the back sides of adjacent busbar-free battery cells.

[0027] The third aspect of the present application provides a photovoltaic module, which adopts the following technical solution:

[0028] A photovoltaic module comprises a front packaging structure, a front adhesive film, a battery string, a back adhesive film and a back packaging structure which are arranged in sequence, wherein the battery string is the battery string as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present application, rather than limiting the present application.

[0030] Figure 1 It is a schematic diagram of the structure of a busbar-less solar cell according to some embodiments of the present application.

[0031] Figure 2 It is a schematic diagram of the structure of a battery substrate according to some embodiments of the present application.

[0032] Figure 3 Schematic diagram of setting bonding area and coating area on the surface of battery substrate according to some embodiments of the present application Figure 1 .

[0033] Figure 4 Schematic diagram of setting bonding area and coating area on the surface of battery substrate according to some embodiments of the present application Figure 2 .

[0034] Figure 5 It is a schematic diagram of the structure of dispensing a colloid on a battery substrate according to some embodiments of the present application.

[0035] Figure 6 It is a schematic diagram of the structure of providing a welding strip on a battery substrate according to some embodiments of the present application.

[0036] Figure 7 The figure is a simplified schematic diagram of the structure of a busbar-less solar cell according to some embodiments of the present application.

[0037] Figure 8 Schematic diagram of the second coating area on the front side of the battery substrate according to some embodiments of the present application.

[0038] Fig. 9 This is a schematic diagram of providing a second welding strip on the front side of a battery substrate according to some embodiments of the present application.

[0039] Fig.10 This is a schematic diagram of disposing a second film on the front side of a battery substrate according to some embodiments of the present application.

[0040] Fig.11 It is a simplified schematic diagram of the structure of the front side of a battery substrate according to some embodiments of the present application.

[0041] Fig.12 It is a schematic diagram of the back structure of a battery string according to some embodiments of the present application.

[0042] Fig.13 It is a schematic diagram of the back structure of a battery string showing the area to be repaired according to some embodiments of the present application.

[0043] Fig.14 for Fig.13 A partial schematic diagram of .

[0044] Fig.15 Schematic diagram of the back structure of a battery string showing blank areas according to some embodiments of the present application.

[0045] Fig.16 for Fig.15 A partial schematic diagram of .

[0046] Fig.17 It is a schematic diagram of the structure of a single chip to be replaced according to some embodiments of the present application.

[0047] Fig.18 It is a schematic diagram of the structure after the single chip to be replaced is installed on the back of the battery string according to some embodiments of the present application.

[0048] Fig.19 for Fig.18 A partial schematic diagram of .

[0049] Fig. 20 It is a schematic diagram of the structure of dispensing bodies on a battery substrate according to other embodiments of the present application.

[0050] Fig.21 Schematic diagram of connection between dispensing body and welding ribbon according to other embodiments of the present application.

[0051] Fig. 22 It is a schematic diagram of the structure of setting welding strips on the battery substrate according to other embodiments of the present application.

[0052] Fig.23 It is a schematic diagram of the structure of setting a film body on a battery substrate according to other embodiments of the present application.

[0053] Fig.24 It is a schematic diagram of the partial structure of the back side of a battery string according to some other embodiments of the present application.

[0054] Fig.25 Schematic diagram of the partial structure of the back side of a battery string showing the area to be repaired according to other embodiments of the present application.

[0055] Fig.26 Schematic diagram of the back side layout structure of a battery string showing blank areas according to other embodiments of the present application.

[0056] Fig. 27 Schematic diagram of the partial structure after the single chip to be replaced is installed on the back of the battery string according to other embodiments of the present application.

[0057] In the figure: 1, battery substrate; 2, welding tape; 3, colloid; 4, film; 5, fine grid; 6, single chip to be replaced; 10, bonding area; 20, coating area; 30, area to be repaired; 40, blank area; 31, colloid; 101, first bonding area; 102, second bonding area; 2', second welding tape; 4', second film; 20', second coating area. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings showing multiple embodiments of the present application. It should be understood that the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments described in the present application, all other embodiments obtained by ordinary technicians in this field without spending creative work will fall within the scope of protection of the present application.

[0059] The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "multiple" means two or more.

[0060] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0061] In the field of photovoltaic cells, the grid line is like a skeleton, supporting the entire photovoltaic cell. After the internal current of the crystalline silicon cell is formed, it is mainly conducted through the metal electrode. The metal electrode can be divided into the main grid and the secondary grid (also known as the fine grid 5). Usually, silver paste is laid on the cell to form the main grid. The main grid is mainly used to converge and connect the current of the secondary grid in series, and the secondary grid is used to collect photogenerated carriers.

[0062] The busbar-free cell has eliminated the main grid and only has a secondary grid. Compared with the busbar cell, on the one hand, it greatly reduces the use of printed silver paste, realizing the elimination of silver and cost reduction. On the other hand, the elimination of the traditional thick busbar line can reduce the shading area, increase the amount of light absorption, and achieve the overall photovoltaic power improvement. Specifically, the busbar-free cell eliminates the main grid in the metal electrode screen printing process, and prints a fine grid 5, optimizing the width and spacing of the secondary grid. In the assembly process, the part where the original main grid and the secondary grid are bonded to gather current is replaced by a polymer film or welding strip (wire) with embedded metal wires, and the cell is interconnected.

[0063] The lamination process is one of the methods to achieve interconnection of battery cells without main grid. In the prior art, the soldering tape is pressed and adhered to the front / back side of the battery cell through the carrier film to connect in series, and then the soldering tape and the fine grid of the battery cell are alloyed by lamination at high temperature. The size of the carrier film is generally slightly smaller than the battery cell, almost covering the head and tail soldering tape of the battery cell, and it has a strong adhesion after hot melting and is not easy to tear. Therefore, when the battery cell is subsequently repaired, it is necessary to tear off the carrier film before overlapping the soldering tape, and then reheat the carrier film to bond and fix the battery cell and the soldering tape. This process is prone to overheating, which will burn the carrier film and produce holes. When the torn carrier film is heated for the second time, the adhesion will be reduced. During lamination, the molten state of the encapsulation film will invade the hole area of ​​the battery cell and the carrier film from all sides, or fill the gap between the soldering tape and the battery to form insulation and produce defects. The above makes conventional replacement and repair very difficult.

[0064] Figure 1 It is a schematic diagram of the structure of a busbar-less solar cell according to some embodiments of the present application.

[0065] One or more embodiments of the present application disclose a busbar-free solar cell. Figure 1 , the busbar-free cell comprises:

[0066] A battery substrate, wherein at least one surface of the battery substrate is provided with a bonding area and a coating area, and the bonding area is located at an end of the battery substrate in a width direction;

[0067] A welding strip, at least one welding strip is provided, and the welding strip extends along the width direction of the battery substrate;

[0068] A fixing structure, wherein the fixing structure comprises a colloid and a film, wherein the colloid is arranged in the bonding area, and the colloid is used to fix the portion of the solder strip located in the bonding area to the battery substrate, and the film is constructed to be sticky, and the film at least partially covers the coating area, so that the portion of the solder strip located in the coating area is fixed to the battery substrate.

[0069] In this embodiment, a bonding area 10 and a coating area 20 are respectively provided on the battery substrate 1. The bonding area 10 is located at the end of the battery substrate 1 in the width direction. It should be understood that the end of the battery substrate 1 in the width direction includes one end and two ends. In this embodiment, the bonding area 10 can be provided at only one end of the battery substrate, or at both ends. A detailed description will be given later, and no further description will be given here. A colloid 3 is provided in the bonding area 10, and the colloid 3 can bond the portion of the welding strip 2 located in the bonding area to the battery substrate 1. The welding strip 2 extends along the width direction of the battery substrate 1. There is at least one welding strip 2, and multiple welding strips 2 are provided in parallel on the battery substrate 1. The coating area 20 is used for laying the film body 4, and the film body 4 is constructed to have viscosity, which can be generated after, for example, heating and melting, or it can be the viscosity of the film body itself. In this way, the film body 4 can also be used to bond the portion of the welding strip 2 located in the coating area 20 to the battery substrate 1. In addition, the film body 4 at least partially covers the coating area 20, that is, the area of ​​the film body 4 is greater than or equal to the area of ​​the coating area 20, so as to ensure that the film body 4 can completely cover the coating area 20. Therefore, the present embodiment fixes the soldering tape 2 by both colloid 3 bonding and film bonding, and the bonding area 10 and the film bonding area 20 respectively fix the soldering tape 2 passing through their respective areas. In this way, on the one hand, the fixing effect of the soldering tape 2 is better than the single method of only using the film, and the cost is better than the solution of only using the colloid 3; on the other hand, when the battery cell is repaired, since the bonding area 10 is located at least at one end in the width direction of the battery substrate 1, the soldering tape 2 in the bonding area 10 is not covered by the film body 4, and therefore the soldering tape 2 can be cut without lifting the film body 4, that is, the chip can be directly removed and repaired in the bonding area 10. Compared with the conventional film coating method, there is no need to tear the film when changing the chip, and there will be no adverse conditions caused by secondary coating, which is conducive to the disassembly, overlapping and other repair operations between battery cells, and helps to improve the success rate of one-time repair and the yield rate of component lamination.

[0070] It should be noted here that although the colloid 3 has a low light transmittance and has a certain shading effect, this embodiment only sets the bonding area in a part of the battery substrate 1, specifically at the end of the battery substrate 1 in the width direction. Therefore, the shading effect is small, and compared with improving the success rate of the battery cell repair in one time, this unfavorable factor can be ignored. In summary, compared with the method of using the colloid 3 in full or the method of using the film body 4 in full, the main grid-free battery cell of this embodiment reduces the cost and improves the success rate of one-time chip removal and repair while satisfying the fixing effect of the welding strip 2.

[0071] It should also be noted that Figure 1 The busbar-less cell shown in the figure is actually a single cell cut from a cell string, so a portion of the welding ribbon 2 connected to the adjacent cell is also connected to the bottom of the cell.

[0072] It can be understood that for a rectangular battery substrate 1, the battery cell has a long side and a short side. Generally, the direction of the long side is defined as the length direction, and the direction of the short side is defined as the width direction. Figure 2 In the figure, L represents the length of the battery substrate 1, and the direction in which it is located is the length direction, and W represents the width of the battery substrate 1, and the direction in which it is located is the width direction. It can also be further understood in conjunction with a battery string, where multiple battery cells are connected in series to form a battery string. Here, the width direction of the battery substrate 1 is consistent with the series connection direction of the battery string. The width direction referred to below is the same as the definition here unless otherwise specified, and will not be repeated.

[0073] In some embodiments, the adhesive area 10 and the coating area 20 are provided on the back of the battery substrate 1, and only the coating area 20 is provided on the front of the battery substrate 1. That is, on the front of the battery substrate 1, only the film body 4 is used to fix the welding strip 2 on the front, and on the back of the battery substrate 1, the film body 4 and the colloid 3 are used to fix the welding strip 2 on the back.

[0074] In this embodiment, the bonding area 10 is only provided on a part of the back side of the battery substrate 1 , and the front side of the battery substrate 1 is coated to further reduce the shading effect of the colloid 3 , so that the overall power of the battery string is better than the solution of using the colloid 3 entirely.

[0075] In order to distinguish it from the coating area on the back of the battery substrate 1, the coating area on the front of the battery substrate 1 is referred to as the second coating area 20', and the second coating area 20' is paved with the second film body 4'. The coating area on the back of the battery pole piece is the first coating area, and the first coating area is paved with the first film body. That is, the adhesive area 10 and the first coating area are set on the back of the battery substrate 1, and the colloid 3 and the first film body are used to fix the welding tape, and only the second coating area 20' is set on the front of the battery substrate 1, and the welding tape is fixed by the second film body 4'.

[0076] It should be understood that both the front and back sides of the battery substrate 1 are provided with welding strips. For the convenience of distinction, the welding strip on the back side of the battery substrate 1 is the first welding strip, and the welding strip on the front side of the battery substrate 1 is called the second welding strip 2'. The welding strips on the front and back sides are connected in sequence to form a battery string, that is, the front electrode (negative electrode) of the "front battery" is welded to the back electrode (positive electrode) of the "back battery", so that multiple battery cells are connected in series in sequence, and leads are welded to the positive and negative electrodes of the solar cell panel in series. Since the stripping generally occurs at the welding strip led out from the back side, the improvement of this embodiment is preferably performed on the back side of the battery substrate 1. Of course, the improvement can also be performed on both the back side and the front side of the battery substrate 1. Therefore, unless otherwise specified below, the coating area 20 mentioned here refers to the first coating area on the back side of the battery substrate 1, the welding strip 2 mentioned here refers to the first welding strip on the back side of the battery substrate 1, and the film body 4 mentioned here refers to the first film body on the back side of the battery substrate 1.

[0077] In some embodiments, the busbar-free cell further comprises a fine grid 5, and the fine grid 5 is arranged on the cell substrate 1 perpendicular to the welding strip 2. Figure 2 , which is a schematic diagram of the structure of a battery substrate 1, wherein the horizontal thin lines are fine grids 5, and the fine grids 5 can be printed on the battery substrate 1 by screen printing. It should be noted that Figure 2 The image shown in the figure may be the front side or the back side of the battery substrate 1 , because fine grids 5 are provided on both the front side and the back side of the battery substrate 1 .

[0078] In some embodiments, Figure 3 As shown, the bonding area 10 is located at one end of the battery substrate 1 in the width direction, and the coating area 20 is located in the remaining area of ​​the battery substrate 1 in the width direction, that is, the surface of the battery substrate 1 is provided with the bonding area 10 and the coating area 20, and the bonding area 10 and the coating area 20 are arranged along the width direction of the battery substrate 1. It can be understood that Figure 3 As shown, along the width direction of the battery substrate 1, the battery substrate 1 is divided into two areas, namely the bonding area 10 and the coating area. Since the area occupied by the bonding area 10 is smaller than the coating area 20, the bonding area 10 is arranged at one end of the battery substrate in the width direction, and the coating area 20 is located in the remaining area of ​​the battery substrate 1 in the width direction.

[0079] In this embodiment, the bonding area 10 is only provided on one side of the battery substrate 1 in the length direction (ie, parallel to the direction of the fine grid 5) to minimize the light shielding effect of the colloid 3 and facilitate the disassembly of the substrate.

[0080] In some embodiments, Figure 2 As shown, the bonding area 10 is located at two ends of the battery substrate 1 in the width direction, and the coating area 20 is located between the bonding areas 10 at the two ends.

[0081] In this embodiment, adhesive areas 10 are provided at both ends of the battery substrate 1 in the width direction, so that the battery substrate 1 can be disassembled on any side in the length direction (i.e., parallel to the fine grid 5), which provides greater convenience for disassembly and increases the flexibility and convenience of operation.

[0082] In some embodiments, Figure 4 As shown, the bonding area 10 includes a first bonding area 101 and a second bonding area 102 , and the first bonding area 101 , the coating area 20 and the second bonding area 102 are sequentially arranged along the width direction of the battery substrate 1 .

[0083] In this embodiment, a first bonding area 101, a coating area 20, and a second bonding area 102 are arranged on the surface (preferably the back side) of the battery substrate 1, that is, auxiliary adhesive bonding areas are arranged on both sides of the length direction of the battery substrate 1, so that a convenient side can be selected when disassembling the battery cell, which increases the flexibility and convenience of the operation and improves the efficiency and accuracy of the disassembly process.

[0084] Please see below Figure 4-Figure 7 , Figure 4-Figure 7 It is a schematic diagram showing that a bonding area 10 and a coating area 20 are arranged on the back of a battery substrate 1 , and the bonding area 10 is arranged at both ends of the battery substrate 1 in the width direction.

[0085] In some embodiments, the width of the first bonding area 101 is 1 / 10-1 / 5 of the width of the battery substrate 1, and / or the width of the second bonding area 102 is 1 / 10-1 / 5 of the width of the battery substrate 1, and / or the width of the coating area 20 is 2 / 5-4 / 5 of the width of the battery substrate 1.

[0086] In at least one embodiment, reference Figure 4 As shown, on the back of the battery substrate 1, the first bonding area 101, the second bonding area 102 and the coating area 20 are all arranged in a direction parallel to the fine grid 5, and the first bonding area 101, the coating area 20 and the second bonding area 102 are distributed in sequence in the width direction of the battery substrate 1. Figure 4 In the figure, a is the width of the first bonding area 101, b is the width of the film covering area 20, and c is the width of the second bonding area 102, wherein a and c may be equal or unequal. In order to minimize the light shielding effect of the colloid 3 and meet the needs of chip removal and repair, assuming that the width of the battery substrate 1 is W, a is designed to be 1 / 10W-1 / 5W, c is designed to be 1 / 10W-1 / 5W, and b is designed to be 2 / 5W-4 / 5W.

[0087] In some embodiments, the colloid 3 includes an adhesive tape, and the adhesive tape extends along the width direction of the battery substrate 1. Here, since the soldering tape 2 extends along the width direction of the battery substrate 1, the adhesive tape is also extended along the width direction of the battery substrate 1. When the soldering tape 2 corresponds to the adhesive tape, that is, when the soldering tape 2 covers the adhesive tape, the contact area between the soldering tape 2 and the adhesive tape can be increased to the greatest extent, thereby improving the soldering tape 2 to be firmly attached to the battery substrate 1.

[0088] In at least one embodiment, the tape may be in strip or block shape, and when it is a block-shaped tape, a plurality of block-shaped tapes are arranged at intervals along the width direction of the battery substrate 1. The design of the block-shaped tape can not only meet the bonding requirements of the welding tape 2, but also minimize the use of the tape, further reducing the light shielding effect of the tape.

[0089] In some embodiments, the colloid 3 includes a dotted colloid 31 , and a plurality of the dotted colloid 31 are spaced apart along the width direction of the battery substrate 1 .

[0090] In at least one embodiment, the glue point 31 is a glue point formed by applying auxiliary glue on the battery substrate 1 by glue dispensing. According to the preset laying position of the welding ribbon 2, the auxiliary glue is sequentially and intermittently arranged on the surface of the battery substrate 1 to form the glue point 31. Thus, the welding ribbon 2 can be bonded and fixed on the battery substrate 1 by the glue point 31.

[0091] In at least one embodiment, the auxiliary adhesive may be one or more of a light-curing adhesive and a thermosetting adhesive.

[0092] In at least one embodiment, the light-curing adhesive is a UV adhesive, which is an acrylic adhesive, and its curing method is UV light curing; the heat-curing adhesive is an epoxy adhesive, and its curing method is heat curing.

[0093] In some embodiments, on the same battery substrate surface, there is a first distance between an end of the colloid 3 away from the coating area 20 and an edge of the battery substrate 1 .

[0094] In this embodiment, the end of the colloid 3 can have a certain distance from the edge of the battery substrate 1, or it can be set at the edge of the battery substrate 1. It can be understood that setting the colloid 3 all the way to the edge of the battery substrate 1 can provide a larger connection area and contact area, improve the connection stability between the welding strip 2 and the battery substrate 1, and reduce the risk of loosening or falling off. It can also be understood that setting the colloid 3 at a distance from the edge of the battery substrate 1 can reduce stress concentration, improve the stability of the battery substrate 1, and prevent the edge of the battery substrate 1 from being over-solved, resulting in operational difficulties or damage. Specifically, it can be designed according to demand, and the colloid 3 can be set directly to the edge of the battery substrate 1 or set at a certain distance.

[0095] In some embodiments, the first distance is 0-10 mm.

[0096] In this embodiment, the distance between the end of the colloid 3 away from the coating area 20 and the edge of the battery substrate 1 is set to 0-10 mm, which can maximize the bonding area between the welding strip 2 and the battery substrate 1, while also avoiding the colloid 3 being located at the edge of the battery substrate 1 to cause inconvenience in the disassembly operation. In at least one embodiment, Figure 5 As shown, when a plurality of dispensing bodies 31 are formed on the back of the battery substrate 1 by dispensing, the distance d between the dispensing body 31 located at the edge and the edge of the battery substrate 1 is in the range of 0-10 mm.

[0097] In at least one embodiment, the solder strip 2 is bonded to the battery substrate 1 by the colloid 3, such as Figure 6As shown, the plurality of welding strips 2 are perpendicular to the fine grid 5, and the plurality of welding strips 2 are parallel and spaced apart. It can be understood that the colloid 3 of the bonding area 10, whether it is a strip of tape, a block of tape spaced apart, or a plurality of point colloids 31 spaced apart, is set at a position determined according to the preset position of the welding strip 2.

[0098] In some embodiments, the film body 4 covers a portion of the bonding area 10 .

[0099] In this embodiment, the film body 4 covers part of the bonding area 10 so that the film body 4 and the bonding area 10 have an intersection area to ensure that the welding strip 2 can be covered by the colloid 3 and / or the film body 4, thereby improving the connection stability between the welding strip 2 and the battery substrate 1.

[0100] In some embodiments, the width of the region of the film body 4 covering the bonding area 10 is less than or equal to 2 mm.

[0101] In this embodiment, the width of the overlapping area between the film body 4 and the bonding area 10 is designed to be no more than 2 mm, which can ensure that the welding strips 2 are all bonded to the battery substrate 1, while avoiding the overlapping area being too large to affect the bonding uniformity between the welding strips 2 and the battery substrate 1.

[0102] In at least one embodiment, after the soldering tape 2 is initially fixed by the colloid 3, a film body 4 (such as Figure 1 Here, the width of the film body 4 slightly exceeds the bonding area 10, that is, the film body 4 and the bonding area 10 have a partial overlapping area. This design is mainly to ensure the bonding and fixing effect of the welding strip 2, and to avoid that part of the welding strip 2 is not covered by the colloid 3 and the film body 4, resulting in a loose connection between it and the battery substrate 1. Figure 7 As shown, the width e of the region of the film body 4 covering the adhesive region 10 satisfies: 0<e≤2mm.

[0103] In some embodiments, two sides of the film body 4 parallel to the welding strip 2 extend beyond the welding strip 2 at two ends by a second distance.

[0104] It can be understood that the welding strips 2 extend along the width direction of the battery substrate 1, and multiple welding strips 2 are arranged in parallel, that is, multiple welding strips 2 are parallel and spaced along the length direction of the battery substrate 1. Therefore, in the length direction of the battery substrate 1, the two welding strips located on the outermost side are the two end welding strips. The two sides of the film body 4 parallel to the welding strips 2 are the two ends of the film body 4 in the length direction of the battery substrate 1. The film body 4 is extended beyond the two end welding strips 4 by a certain distance, so that when welding in series, it can be ensured that the two welding strips at the edge can be firmly fixed.

[0105] In some embodiments, the second distance is 2-10 mm.

[0106] In this embodiment, the distance between the two sides of the film body 4 and the welding strip 2 that extend beyond the welding strips at both ends is set to 2-10mm, which exceeds a certain distance to ensure that the welding strips at both ends are firmly fixed, while the distance is not too large. Therefore, during the subsequent lamination process, it is ensured that the outer packaging film will not invade the film body, avoiding problems such as welding strip deviation and virtual connection.

[0107] In at least one embodiment, Figure 7 As shown, the welding strip 2 extends along the width direction of the battery substrate 1, and multiple welding strips 2 extend along the width direction of the battery substrate 1 and are parallel and spaced apart. The two ends of the welding strip 2 are bonded to the bonding area 10 through the colloid 3. The middle part of the welding strip 2 is covered by the film 4, and the two sides of the film 4 parallel to the welding strip 2 exceed the welding strip 2 at the two ends by a certain distance. Figure 7 It is represented by f, and the value range of f is 2-10 mm. It should be understood that the distances of the two sides of the film body 4 beyond the welding strip 2 can be equal or unequal.

[0108] In addition, it should be noted that in order to avoid affecting the optical positioning recognition when the battery string is automatically arranged, the film body 4 generally does not exceed the size of the battery substrate 1, that is, the length of the film body 4 is not greater than the length L of the battery substrate 1.

[0109] It should also be noted that the film body 4 is generally made of EVA, POE or PO polyolefin materials, among which EVA and POE are thermosetting materials, and both thermoplastic and thermosetting PO polyolefin materials can be used. Therefore, after the film body 4 is heated and melted, the welding strip 2 can be further bonded and fixed to the surface of the battery substrate 1.

[0110] In some embodiments, a second coating area 20' is provided on the front side of the battery substrate 1, and a second film body 4' is laid on the second coating area 20'. After the second film body 4' is heated, the second welding strip 2' is fixed on the battery substrate 1, wherein the distance h between the two sides of the second film body 4' in the width direction and the edge of the battery substrate 1 satisfies: 0<h≤4mm; the distance g of the second film body 4' parallel to the two sides of the second welding strip 2' beyond the edge of the second welding strip 2' is 2-10mm.

[0111] Please refer to the following Figure 8-Figure 11 , Figure 8-Figure 11 It is a schematic diagram showing that only the coating area is provided on the front side of the battery substrate 1.

[0112] In at least one embodiment, Figure 8 As shown, the front side of the battery substrate 1 is provided with a second coating area 20'; Fig. 9 As shown, a plurality of second welding strips 2' are evenly and spacedly arranged along the direction perpendicular to the fine grid 5 on the front side of the battery substrate 1, that is, the second welding strips 2' are perpendicular to the fine grid 5; Fig.10As shown, the second film body 4' is laid in the second film coating area 20'. After the second film body 4' is heated, the second welding strip 2' is bonded and fixed to the surface of the battery substrate 1; generally, the film body 4 does not exceed the size of the battery cell, such as Fig.11 As shown, the distance between the second film 4' and the edge of the battery substrate 1 is h>0, usually 0-4mm; the second film 4' parallel to the second welding strip 2' needs to exceed the second welding strip 2' and cover the second welding strip 2' as a whole, that is, g>0, usually 2-10mm.

[0113] One or more embodiments of the present application further disclose a battery string. The battery string includes a busbar-free battery cell as described in any one of the above. In at least one embodiment, the battery string includes a plurality of busbar-free battery cells, and the plurality of busbar-free battery cells are connected in series via welding strips (including a first welding strip and a second welding strip 2'). Fig.12 As shown, it is a schematic diagram of the back structure of the battery string. It can be seen that multiple busbar-free battery cells are connected in series to ensure the current collection capacity and output power of the battery string.

[0114] In at least one embodiment, the welding strips 2 are sequentially connected to the front and back sides of the adjacent busbar-free solar cells. That is, the welding strips on the front side of the busbar-free solar cell described above are connected to the welding strips on the back side of the adjacent busbar-free solar cell, so that multiple busbar-free solar cells are sequentially connected in series to form a solar cell string.

[0115] In at least one embodiment, the welding strips are sequentially connected to the back of the adjacent non-busbar cells, so that the cell string can be applied to the field of back contact (BC) cells. BC cells are solar cells that have both PN junctions and metal contacts on the back of the solar cell, creating more light-absorbing area for the front side and improving the overall photoelectric conversion efficiency of the cell. BC cells can be further divided into IBC cells, which have metal electrodes arranged in a forked shape on the back of the cell. It can be understood that since the IBC electrodes are all on the back, they can be connected with interconnecting welding strips.

[0116] One or more embodiments of the present application further disclose a photovoltaic assembly, wherein the photovoltaic assembly comprises the battery string as described above.

[0117] In at least one embodiment, the photovoltaic module includes a plurality of battery strings, and the plurality of battery strings are connected in series or in parallel via a bus bar.

[0118] In at least one embodiment, the photovoltaic module further includes a front packaging structure, a front adhesive film, a battery string, a back adhesive film and a back packaging structure which are arranged in sequence.

[0119] In at least one embodiment, the front packaging structure and the back packaging structure include one of tempered glass, PET (thermoplastic polyester), PC (polycarbonate polyester), PVDF (polyvinylidene fluoride), etc. These materials have excellent light transmittance and can effectively ensure that the surface of the photovoltaic cell receives sufficient light.

[0120] In at least one embodiment, the front adhesive film and the back adhesive film include one of materials such as EVA (ethylene-vinyl acetate copolymer), PVB (polyvinyl butyral), and POE (polyolefin elastomer).

[0121] In at least one embodiment, the photovoltaic module further includes a frame, and the battery string is disposed between two glass plates, and then the frame is installed for sealing.

[0122] Please refer to the following Figure 13-Figure 19 , Figure 13-Figure 19 The schematic structural diagram of the back side of the battery string is shown, wherein a bonding area 10 and a coating area 20 are provided on the back side of the busbar-free battery cell, and the bonding area 10 is provided at both ends of the battery substrate 1 in the width direction.

[0123] Taking the above-mentioned battery string composed of busbar-free battery cells as an example, the implementation process of repairing and replacing the photovoltaic modules of one or more embodiments of the present application is as follows:

[0124] like Fig.13 As shown in FIG. 1 , it is a schematic diagram of the structure on the back of the battery string. The battery cells selected by the rectangular box in the figure need to be replaced. The area of ​​the battery cells to be repaired in the battery string is called the area to be repaired 30. Fig.14 As shown, from Fig.13 The partial schematic diagram taken in FIG. 1 clearly shows the area 30 to be repaired.

[0125] When a cell string in a photovoltaic module needs to be repaired and replaced, it is only necessary to cut off the head and tail of the welding strip 2 on the back of the cell to be replaced without tearing the film 4. Fig.15 , which is a schematic diagram of the structure after the battery cell to be replaced is removed from the back of the battery string. The blank area 40 in the figure is the position of the battery cell to be replaced in the battery string. Fig.16 for Fig.15 A partial schematic diagram is shown in the figure to clearly show the blank area.

[0126] After removing the battery cell to be replaced from the battery string, the head and tail welding strips 2 of the prepared single cell 6 to be replaced are overlapped with the area of ​​the removed battery string welding strip 2, that is, the replacement and repair of the cell is completed in the back bonding area 10. The whole process is simple and convenient to operate, which greatly improves the efficiency of one-time repair. Fig.17 As shown in FIG. 1 , it is a schematic diagram of the structure of the single chip 6 to be replaced, such as Fig.18 , which is a schematic diagram of the structure after the single chip 6 to be replaced is installed on the back of the battery string, Fig.19for Fig.18 Partial schematic diagram. In the figure, i is the distance between the lapped solder strip 2 and the first row of dot colloid 31, usually 0-5mm; j and k are the overlapping lengths of the lapped solder strip 2, usually ≥3mm. After lap welding, the welding effect needs to be checked. There should be no tin accumulation, tin nails, or burrs. The lapped solder strip 2 cannot be forked, and there should be no burrs after welding.

[0127] Please refer to the following Figure 20-23 , is a case where the bonding area 10 and the coating area 20 are arranged on the back of the battery substrate 1, and the bonding area 10 is arranged at one end in the width direction of the battery substrate 1. Figure 20-23 The schematic diagram of the structure of the main grid-free battery cell is shown in FIG. A fine grid 5 is provided on the battery substrate 1. One end of the battery substrate 1 in the width direction is a bonding area 10. A dispensing body 31 is provided on the bonding area 10 according to the preset position of the welding strip 2. A plurality of dispensing bodies 31 extend along the width direction of the battery substrate 1 ( Fig. 20 The soldering tape 2 is laid on the battery substrate 1, and the soldering tape 2 extends along the width direction of the battery substrate 1. The soldering tape 2 is pre-fixed by the dispensing body 31 provided on the bonding area 10. At this time, the soldering tape 2 is bonded and fixed to one end of the battery substrate 1 in the width direction by the dispensing body 31 ( Fig.21 ). It should be noted that Fig.21 In order to clearly see the connection relationship between the dot colloid 31 and the soldering ribbon 2, the structure of the fine grid 5 is not shown. Fig. 22 FIG. 2 is a diagram showing the structure of the fine gate 5. Fig.23 As shown, the dispensing body 31 is arranged at one end of the battery substrate 1 in the width direction, and the remaining area along the width direction of the battery substrate 1 will be covered with the film body 4, and the film body 4 covers the welding strip 2, thereby bonding and fixing the welding strip 2 to the battery substrate 1.

[0128] Taking the above-mentioned busbar-free cell as an example, the repair and replacement process of the photovoltaic module composed of it is explained. Fig.24 As shown in FIG. 1 , it is a schematic diagram of the partial structure of the back side of the battery string. It can be seen that the back side of the busbar-free battery cell is provided with a bonding area 10 at only one end in the width direction, and a dispensing body 31 is provided on the bonding area 10. The welding strip 2 is respectively bonded and fixed to one end in the width direction of the battery substrate 1 through the dispensing body 31, and is bonded and fixed to the other end in the width direction of the battery substrate through the film body 4, that is, the remaining area in the width direction of the battery substrate 1. Fig.25 As shown, the repair area 30 is clearly shown, and the battery cell selected by the rectangular box in the figure needs to be replaced. When replacing the cell, the head and tail of the back welding strip 2 of the battery cell to be replaced are cut off without tearing the film body 4. Fig.26As shown in the figure, it is a schematic diagram of the structure after the battery cell to be replaced is removed from the back of the battery string. The blank area 40 in the figure is the position of the battery cell to be replaced in the battery string. After removing the battery cell to be replaced from the battery string, the head and tail welding strips 2 of the prepared single cell 6 to be replaced are overlapped with the area of ​​the welding strip 2 of the removed battery string, and the replacement and repair are completed at the back bonding area 10. Fig. 27 As shown, it is a schematic diagram of the structure after the single chip 6 to be replaced is installed on the back of the battery string. In the figure, i is the distance between the lap welding strip 2 and the first row of colloid 31, which is usually 0-5mm; j and k are the overlapping lengths of the lap welding strip 2, which are usually ≥3mm. After lap welding, the welding effect needs to be checked. There should be no tin accumulation, tin nails, or burrs. The lap welding strip 2 cannot be forked, and there should be no burrs after welding.

[0129] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A busbar-free solar cell, characterized in that: include: A battery substrate, wherein at least one surface of the battery substrate is provided with a bonding area and a coating area, and the bonding area is located at an end of the battery substrate in a width direction; A welding strip, at least one welding strip is provided, and the welding strip extends along the width direction of the battery substrate; A fixing structure, wherein the fixing structure comprises a colloid and a film, wherein the colloid is arranged in the bonding area, and the colloid is used to fix the portion of the solder strip located in the bonding area to the battery substrate, and the film is constructed to be sticky, and the film at least partially covers the coating area, so that the portion of the solder strip located in the coating area is fixed to the battery substrate.

2. The busbar-free solar cell according to claim 1, characterized in that: On the same surface of the battery substrate, there is a first distance between an end of the colloid away from the coating area and an edge of the battery substrate.

3. The busbar-free solar cell according to claim 2, characterized in that: The first distance is 0-10 mm.

4. The busbar-free solar cell according to claim 1, characterized in that: The film body covers a portion of the bonding area.

5. The busbar-free solar cell according to claim 4, characterized in that: The width of the region where the film covers the bonding area is less than or equal to 2 mm.

6. The busbar-free solar cell according to claim 1, characterized in that: The two side edges of the film body parallel to the welding strip extend beyond the two ends of the welding strip by a second distance.

7. The busbar-free solar cell according to claim 6, characterized in that: The second distance is 2-10 mm.

8. The busbar-free solar cell according to any one of claims 1 to 7, characterized in that: The back side of the battery substrate is provided with the bonding area and the coating area.

9. The busbar-free solar cell according to any one of claims 1 to 7, characterized in that: The bonding area is located at one end of the battery substrate in the width direction, and the coating area is located in the remaining area of ​​the battery substrate in the width direction.

10. The busbar-free solar cell according to any one of claims 1 to 7, characterized in that: The bonding area is located at two ends of the battery substrate in a width direction, and the coating area is located between the bonding areas at the two ends.

11. The busbar-less solar cell according to claim 10, characterized in that: The bonding area includes a first bonding area and a second bonding area; the width of the first bonding area is 1 / 10-1 / 5 of the width of the battery substrate, and / or the width of the second bonding area is 1 / 10-1 / 5 of the width of the battery substrate.

12. The busbar-less solar cell according to claim 10, characterized in that: The width of the coating area is 2 / 5-4 / 5 of the width of the battery substrate.

13. The busbar-less solar cell according to any one of claims 1 to 7, characterized in that: The colloid includes an adhesive tape, and the adhesive tape extends along a width direction of the battery substrate.

14. The busbar-less solar cell according to any one of claims 1 to 7, characterized in that: The colloid includes a dotted colloid, and a plurality of the dotted colloids are arranged at intervals along the width direction of the battery substrate.

15. A battery string, characterized in that: It comprises the busbar-free solar cell according to any one of claims 1 to 14, wherein the welding strips are sequentially connected to the front and back sides of adjacent busbar-free solar cells.

16. A battery string, characterized in that: It comprises the busbar-free solar cell according to any one of claims 1 to 14, wherein the welding strips are sequentially connected to the back sides of adjacent busbar-free solar cells.

17. A photovoltaic module, characterized in that: It comprises a front packaging structure, a front adhesive film, a battery string, a back adhesive film and a back packaging structure which are arranged in sequence, and the battery string is the battery string according to claim 15 or 16.

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