Photovoltaic cell string, photovoltaic laminated member and photovoltaic assembly

Abstract

The utility model provides a photovoltaic cell string, a photovoltaic laminated member and a photovoltaic assembly, and relates to the field of photovoltaic technology. The photovoltaic cell string comprises an insulating strip, a bus bar, a plurality of electrically connected photovoltaic cells and a plurality of solder strips arranged on the photovoltaic cells, the insulating strip is arranged on the photovoltaic cells, and the bus bar is arranged on the side, away from the photovoltaic cells, of the insulating strip; a plurality of thin grid lines with opposite polarities are arranged on the back surface of the photovoltaic battery piece, and the plurality of thin grid lines with opposite polarities are connected with the plurality of welding strips in a one-to-one correspondence manner; the insulating strip is provided with a plurality of first through holes, each welding strip connected with one of the thin grid lines with the same polarity in the plurality of welding strips is provided with a lug boss, and each lug boss penetrates through the corresponding first through hole and is connected with the bus bar; and each of the plurality of solder strips connected with the other type of homopolar fine grid line is electrically isolated from the bus bar through an insulating strip. The photovoltaic cell string can ensure the connection reliability between the bus bar and the solder strip.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, in particular to a photovoltaic cell string, a photovoltaic laminate and a photovoltaic assembly. Background Art

[0002] The statements in this section merely provide background technology related to the present invention and do not necessarily constitute prior art.

[0003] Back-contact photovoltaic cells are different from conventional photovoltaic cells. They place both positive and negative electrodes on the back of the cell, thus avoiding the optical loss on the front of conventional photovoltaic cells and improving the photoelectric conversion efficiency of the photovoltaic cell.

[0004] PV cell strings typically require busbars around their periphery to connect to the cell ribbons, creating a current collector. These busbars create an inactive area on the front of the PV cells. Related technologies have attempted to reduce this inactive area by relocating the ribbons and / or busbars to the back of the PV cell string, thereby improving the cell's power generation efficiency. However, this does not guarantee the cell's product reliability. Utility Model Content

[0005] The purpose of the utility model is to provide a photovoltaic cell string, a photovoltaic laminate, and a photovoltaic module to solve the technical problem that photovoltaic cells have poor reliability while having high power generation efficiency.

[0006] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a photovoltaic cell string, comprising an insulating strip, a bus bar, a plurality of electrically connected photovoltaic cells, and a plurality of welding strips provided on the photovoltaic cells, wherein the insulating strip is provided on the photovoltaic cells, and the bus bar is provided on a side of the insulating strip facing away from the photovoltaic cells;

[0008] A plurality of thin grid lines with opposite polarities are provided on the back of the photovoltaic cell, and the plurality of thin grid lines with opposite polarities are connected to the plurality of welding ribbons in a one-to-one correspondence;

[0009] The insulating strip has a plurality of first through holes, and each of the plurality of welding strips connected to one of the same polarity fine grid lines has a protrusion, and each of the protrusions passes through the corresponding first through hole and is connected to the bus bar;

[0010] Each welding strip among the plurality of welding strips connected to another type of fine grid line of the same polarity is electrically isolated from the bus bar by the insulating strip.

[0011] According to at least one embodiment of the present invention, the busbar has a plurality of second through holes corresponding to the first through holes, and each of the protrusions passes through the corresponding first through hole to the second through hole and is connected to the busbar.

[0012] According to at least one embodiment of the present invention, the cross-sectional area of the first through hole is greater than or equal to the cross-sectional area of the second through hole.

[0013] According to at least one embodiment of the present invention, the protrusion is welded to the bus bar; and / or,

[0014] The protrusion is a tin-coated protrusion; and / or,

[0015] The busbars and the welding strips are both tin-coated metal strips.

[0016] According to at least one embodiment of the present invention, the protrusion and the welding strip are formed integrally.

[0017] According to at least one embodiment of the present invention, the raised portion includes a bent structure formed by bending the welding strip; and / or,

[0018] The raised portion includes a boss structure formed on the welding strip.

[0019] According to at least one embodiment of the present invention, the top end of the protrusion is flush with or higher than the surface of the busbar facing away from the insulating strip.

[0020] In a second aspect, the present invention further provides a photovoltaic laminate comprising a back cover and a plurality of electrically connected photovoltaic cell strings, wherein the photovoltaic cell strings are the photovoltaic cell strings described in the first aspect.

[0021] The back cover is arranged on the back of the photovoltaic cell string through an adhesive film. A plurality of recessed portions are formed on the surface of the back cover facing the photovoltaic cell string. At least part of the recessed portions is opposite to the raised portion of the welding strip.

[0022] According to at least one embodiment of the present invention, when the back cover is photovoltaic glass, the recessed portion is a groove provided on the glass cover;

[0023] When the back cover is a photovoltaic back sheet, the recessed portion includes a groove formed by bending the photovoltaic back sheet.

[0024] In a third aspect, the present invention further provides a photovoltaic assembly comprising the photovoltaic laminate according to the second aspect.

[0025] One or more technical solutions provided in the exemplary embodiments of the present invention can achieve at least one of the following beneficial effects.

[0026] In the photovoltaic cell string of the exemplary embodiment of the present invention, a raised portion is provided on each welding ribbon to be connected to the busbar (a welding ribbon connected to a thin grid line of the same polarity), and the raised portion extends from the corresponding first through hole of the insulating strip to form an electrical connection with the busbar; while no raised portion is provided for each welding ribbon (a welding ribbon connected to another thin grid line of the same polarity, which should not be electrically connected to the busbar), and the busbar and each welding ribbon (the welding ribbon that should not be electrically connected to the busbar) are electrically isolated due to the insulating strip. The electrical isolation of the insulating strip allows the busbar to be located on the back of the photovoltaic cell string. Compared with the prior art in which the busbar is located in the peripheral area of the photovoltaic cell string, the ineffective area of the photovoltaic cell string is reduced, thereby improving the power generation efficiency.

[0027] Compared with the prior art, no protrusions are provided on the welding strips to be connected to the busbar (the welding strips connected to a thin grid line of the same polarity), and the welding connection between the busbar and the welding strip is formed only by the tin material coated on the welding strip and / or the busbar. Due to the molten fluidity of the tin material, it is difficult to ensure the welding reliability of the busbar and the welding strip. The busbar of the photovoltaic cell string of the exemplary embodiment of the present utility model and the welding strip to be connected are physically abutted and welded by the protrusions. Since the protrusions have a fixed shape, the connection reliability between the busbar and the welding strip can be guaranteed. Therefore, on the basis of improving the power generation efficiency, the reliability and qualification rate of the photovoltaic cell string and its subsequent products can be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention, and are included in and constitute a part of this specification.

[0029] Figure 1 is a schematic structural diagram of a photovoltaic cell string array according to an embodiment of the present utility model;

[0030] Figure 2 yes Figure 1 A schematic diagram of the structure of a battery string;

[0031] Figure 3 Schematic diagram of the structure of a photovoltaic cell string array (with insulating strips) according to an embodiment of the present utility model;

[0032] Figure 4 yes Figure 3 A schematic diagram of the structure of a battery string (with insulating strips);

[0033] Figure 5 It is a schematic structural diagram of a photovoltaic cell string array (with insulating bars / bus bars) according to an embodiment of the present utility model;

[0034] Figure 6 yes Figure 5 A schematic diagram of the structure of a battery string (with insulation bars / bus bars);

[0035] Figure 7 yes Figure 6 A schematic diagram of the structure of a battery cell at one end (with an insulating strip / bus bar);

[0036] Figure 8A yes Figure 7 AA cross-sectional structural diagram;

[0037] Figure 8B yes Figure 7 BB cross-sectional structure diagram;

[0038] Figure 8C yes Figure 7 Schematic diagram of CC cross-section structure;

[0039] Figure 8D yes Figure 7 DD cross-sectional structure diagram;

[0040] Figure 9 yes Figure 6 A schematic diagram of the exploded structure of a battery cell at one end (with an insulating strip / bus bar);

[0041] Figure 10 yes Figure 6 A schematic diagram of the exploded structure of a middle cell (with insulating strips / bus bars);

[0042] Figure 11 is a schematic diagram of a three-dimensional exploded structure of a photovoltaic laminate according to an embodiment of the present utility model;

[0043] Figure 12 It is a schematic diagram of the three-dimensional exploded structure of a photovoltaic laminate according to another embodiment of the present invention.

[0044] Reference numerals:

[0045] 100, front cover;

[0046] 200, front film;

[0047] 300, photovoltaic cell string array; 310, photovoltaic cell string; 311, welding ribbon; 311a, protrusion; 312, cell; 320, bus bar; 321, second through hole; 330, insulating strip; 331, first through hole;

[0048] 400, rear film;

[0049] 500, rear cover; 500a, recessed portion. DETAILED DESCRIPTION

[0050] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0051] Back-contact (BC) photovoltaic cells are characterized by placing both the positive and negative electrodes on the back of the cell, eliminating light obstruction by the front electrodes. This maximizes the use of incident light, reduces optical losses, and improves the photovoltaic cell's photoelectric conversion efficiency. Back-contact photovoltaic cells are highly compatible with other high-efficiency photovoltaic cell structures, encompassing a variety of technological approaches, such as interdigitated back contact (IBC), heterojunction back contact (HBC), and passivated back contact (PBC).

[0052] In the field of photovoltaic cell technology, the pursuit of lower production costs and higher photoelectric conversion efficiency is the industry's core goal. High-density packaging of photovoltaic modules primarily reduces the gaps between photovoltaic cells / strings to maximize the cell area ratio within the module. Assuming the module power remains constant, high-efficiency photovoltaic modules have a smaller module area, which can save on the use of key materials and reduce module costs.

[0053] Typically, the busbars in photovoltaic cells occupy ineffective areas at both ends and in the middle of the cell string. Back-contact photovoltaic cells can reduce this ineffective area and improve power generation efficiency by flipping and folding the busbars to the back. In related technologies, back-contact photovoltaic cells flip and fold the busbars to the back, requiring the bending of welding ribbons (interconnecting strips) and / or busbars to interconnect photovoltaic cells / strings. However, the welding effect between the welding ribbons and the busbars cannot be guaranteed, resulting in the inability to guarantee production yield and the reliability of subsequent products.

[0054] Figure 1 Schematic diagram of the structure of a photovoltaic cell string array according to an embodiment of the present invention. Figure 1 As shown, the photovoltaic cell strings 310 are formed using back contact technology. Exemplarily, the photovoltaic cell string array 300 has six photovoltaic cell strings 310 from top to bottom.

[0055] Figure 2 yes Figure 1A schematic diagram of the structure of a battery string. Figure 2 As shown, each photovoltaic cell string 310 includes three or more electrically connected photovoltaic cells 312, and each photovoltaic cell string 310 includes at least two photovoltaic cells 312 located at the two ends, and one photovoltaic cell 312 located in the middle. The photovoltaic cells 312 are electrically connected by welding ribbons 311. In the same photovoltaic cell 312, multiple welding ribbons 311 are arranged from top to bottom. Some welding ribbons 311 are connected to fine grid lines with positive polarity, and other welding ribbons 311 are connected to fine grid lines with negative polarity. The welding ribbons 311 connected to the fine grid lines with positive polarity and the welding ribbons 311 connected to the fine grid lines with negative polarity are arranged alternately from top to bottom.

[0056] It should be understood that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0057] For example, the cells 312 in the photovoltaic cell string 310 may have a spacing between them, and the spacing between each cell is the same. The cells 312 in the photovoltaic cell string 310 may also be overlapped to reduce the area occupied by the photovoltaic cell string 310 and improve power generation efficiency.

[0058] Figure 5 It is a schematic structural diagram of a photovoltaic cell string array (with insulating bars / bus bars) according to an embodiment of the present utility model; Figure 6 yes Figure 5 A schematic diagram of the structure of a battery string (with insulation bars / bus bars); Figure 9 yes Figure 6 Schematic diagram of the three-dimensional exploded structure of a battery cell (with insulation strips / bus bars) at one end. Figure 5 、 Figure 6 and Figure 9As shown, an exemplary embodiment of the present invention provides a photovoltaic cell string, including an insulating strip 330, a bus bar 320, a plurality of electrically connected photovoltaic cell sheets 312 and a plurality of welding strips 311 arranged on the photovoltaic cell string 310, the insulating strip 330 is arranged on the photovoltaic cell string 310, and the bus bar 320 is arranged on the side of the insulating strip 330 away from the photovoltaic cell string 310; a plurality of fine grid lines with opposite polarities are provided on the back side of the photovoltaic cell sheet 312, and the plurality of fine grid lines with opposite polarities are connected to the plurality of welding strips 311 in a one-to-one correspondence; the insulating strip 330 has a plurality of first through holes 331, and each welding strip 311 connected to one of the fine grid lines of the same polarity in the plurality of welding strips 311 has a protrusion 311a, and each protrusion 311a passes through the corresponding first through hole 331 and is connected to the bus bar 320; each welding strip 311 connected to another fine grid line of the same polarity in the plurality of welding strips 311 is electrically isolated from the bus bar 320 by the insulating strip 330.

[0059] In practical applications, such as Figure 3 and Figure 4 As shown, in the photovoltaic cell string array 300, three insulating strips 330 are arranged in the vertical direction, wherein one insulating strip 330 spans the back surface of the cell 312 at the same end of each photovoltaic cell string 310, another insulating strip 330 spans the back surface of the cell 312 at the other end of each photovoltaic cell string 310, and the third insulating strip 330 spans the back surface of the cell 312 at the middle portion of each photovoltaic cell string 310. Figure 3 Schematic diagram of the structure of a photovoltaic cell string array (with insulating strips) according to an embodiment of the present utility model; Figure 4 yes Figure 3 Schematic diagram of the structure of a battery string (with insulating strips).

[0060] For example, Figure 9 and Figure 10 As shown, the first through holes 331 on the insulating strip 330 correspond one-to-one to the protrusions 311a on the corresponding welding strips 311. When the insulating strip 330 is attached to the battery cell 312, the protrusions 311a on the welding strips 311 pass through the corresponding first through holes 331 to be electrically connected to the bus bar 320 subsequently provided on the insulating strip 330.

[0061] like Figure 9 On the battery cell 312 shown, for example, each welding strip 311 with a raised portion 311a is connected to the positive polarity fine grid line, while each welding strip 311 without a raised portion 311a is connected to the negative polarity fine grid line, and the welding strips 311 with a raised portion 311a and the welding strips 311 without a raised portion 311a are arranged alternately with each other. Figure 10 The electrical connection structure between the welding strip 311 and the bus bar 320 and the insulating strip 330 is as follows Figure 9Similar, but different Figure 10 The cell 312 in the middle of the photovoltaic cell string 310 is shown. Figure 9 The photovoltaic cell 312 is located at the end of the photovoltaic cell string 310.

[0062] like Figure 5 and Figure 6 As shown, after three insulating strips 330 are provided on the photovoltaic cell string array 300, bus bars 320 are respectively attached to each insulating strip 330. The area of the bus bar 320 can be smaller than the area of the corresponding insulating strip 330, or in other words, the orthographic projection of the bus bar 320 on the surface of the insulating strip 330 is located within the surface of the insulating strip 330 to ensure that the bus bar 320 is electrically isolated from the welding strip 311 that should not be electrically connected.

[0063] When the busbar 320 is placed behind the insulating strip 330, it can physically contact the protrusion 311a extending from the first through hole 331 of the insulating strip 330, and the two can be electrically connected by welding. Because the protrusion 311a has a fixed shape and forms physical contact, the welding reliability between the two is high.

[0064] Figure 7 yes Figure 6 A schematic diagram of the structure of a battery cell at one end (with an insulating strip / bus bar); Figure 8A yes Figure 7 AA cross-sectional structural diagram; Figure 8B yes Figure 7 BB cross-sectional structure diagram; Figure 8C yes Figure 7 Schematic diagram of CC cross-section structure; Figure 8D yes Figure 7 DD cross-sectional structure diagram. Figure 7 and Figure 8A As shown, the bus bar 320 is not provided in the end region of the insulating strip 330, that is, the end of the bus bar 320 is close to a welding strip 311 having a protrusion 311a; Figure 8B As shown, in the connection area between the bus bar 320 and the welding ribbon 311, the welding ribbon 311 is located on the battery cell 312, and its protrusion 311a passes through the first through hole 331 of the insulating strip 330 to form physical contact with the bus bar 320; Figure 8C As shown, in the area between adjacent welding strips 311, the bus bar 320 is electrically isolated from the battery cell 312 by the insulating strip 330; Figure 8D As shown, in the region of the soldering ribbon 311 without the protrusion 311 a , the bus bar 320 is electrically isolated from the soldering ribbon 311 without the protrusion 311 a by the insulating strip 330 .

[0065] From the above, it can be seen that the bus bar 320 can form an effective electrical connection with the welding ribbon 311 to be connected, and be electrically isolated from the welding ribbon 311 that should not be electrically connected, so that the bus bar 320 can be set on the back side of the back-contact photovoltaic cell string, reducing the ineffective area occupied by the bus bar 320 set on the peripheral edge of the photovoltaic cell string, that is, hiding the bus bar 320, improving the power generation efficiency of the photovoltaic module, and at the same time ensuring the welding effect between the bus bar 320 and the welding ribbon 311, ensuring the reliability and pass rate of subsequent products.

[0066] Exemplarily, the protrusion 311a is a protrusion 311a with tin solder, and the busbar 320 can be a tin-coated metal strip. Exemplarily, the busbar 320 is a flat copper strip coated with tin solder; the welding strip 311 can also be a tin-coated metal strip, for example, it is a flat copper strip coated with tin solder.

[0067] Since the busbar 320 needs to carry a much larger current than the soldering strip 311 (interconnection strip), the busbar 320 is generally a tinned flat copper strip with a larger cross-sectional area than the soldering strip 311, and its cross-sectional area is generally more than 1mm. 2 The busbars 320 are generally located at both ends of the photovoltaic cell string 310, and the welding ribbons 311 are welded to the busbars 320 at both ends of the photovoltaic cell string, which not only affects the power generation efficiency but also looks unsightly.

[0068] After the busbar 320 is placed on the insulating bar 330, the protrusion 311a coated with tin solder and the busbar 320 can be welded and fixed by infrared welding. Due to the fixed shape of the protrusion 311a, the fluid tin solder can be accurately melted at the connection between the protrusion 311a and the busbar 320, thereby ensuring the welding effect.

[0069] It is understandable that the protrusion 311 a may also be made of a conductive metal material that is not coated with tin, such as copper, and the tin solder coated on the bus bar 320 may be used to complete the welding between the two.

[0070] For example, the raised portion 311 a may be integrally formed with the soldering strip 311 to reduce the processing cost of the soldering strip 311 , and the raised portion 311 a is more stable on the soldering strip 311 .

[0071] For example, the protrusion 311a includes a bent structure formed by bending the welding strip 311. Since the welding strip 311 is a flat copper strip, it is suitable for forming a "J"-shaped structure through a bending device in terms of thickness and ductility. Figure 8B The structure of the protrusion 311a shown simplifies the processing technology and reduces costs.

[0072] In an optional embodiment, the protrusion 311a includes a boss structure formed on the welding strip 311. The boss structure can be formed by stamping, or by using a mold during the molding process of the welding strip 311.

[0073] In another optional embodiment, the protrusion 311 a may also be pre-fixed on the welding strip 311 by welding.

[0074] Considering the problem that the welding effect between the bus bar 320 and the welding ribbon 311 cannot be effectively verified, in the photovoltaic cell string provided by the exemplary embodiment of the present invention, the bus bar 320 has a plurality of second through holes 321 corresponding to the first through holes 331, and each protrusion 311a passes through the corresponding first through hole 331 to the second through hole 321 and is connected to the bus bar 320. Figure 8B 、 Figure 9 and Figure 10 shown.

[0075] In actual applications, the second through-hole 321 of the busbar 320 corresponds one-to-one with the first through-hole 331 of the insulating strip 330. The raised portion 311a can pass through the first through-hole 331, with a portion embedded in the second through-hole 321. That is, the top of the raised portion 311a can be flush with the surface of the busbar 320 facing away from the insulating strip 330, and the size and shape of the second through-hole 321 are compatible with the raised portion 311a. After welding, the weld quality between the busbar 320 and the raised portion 311a can be observed from above the busbar 320 to determine, for example, whether there is a cold weld. Alternatively, the weld quality between the busbar 320 and the raised portion 311a can be determined from above the busbar 320 using an image acquisition device and machine image recognition.

[0076] Compared to the prior art, the welding area between the busbar 320 and the welding ribbon 311 is blocked by the busbar 320, making it impossible to visually inspect or image-collect the welding reliability. To verify the welding reliability between the two, a destructive tensile test is required. In the photovoltaic cell string of the exemplary embodiment of the present invention, the raised portion 311a of the welding ribbon 311 is extended into the second through-hole 321 of the busbar 320 for welding connection. On the one hand, the physical connection and welding of the two ensures the welding effect; on the other hand, since the welding area between the two is not blocked by the busbar 320, it is possible to intuitively determine whether there is a problem such as a cold weld between the busbar 320 and the welding ribbon 311, thereby ensuring the qualified rate of the back-contact photovoltaic cell string product and the reliability of subsequent products.

[0077] In some embodiments, the cross-sectional area of the first through-hole 331 is greater than or equal to the cross-sectional area of the second through-hole 321. The cross-sectional area of the second through-hole 321 can be consistent with the cross-sectional area of the protrusion 311a to maintain welding reliability between the two. The cross-sectional area of the first through-hole 331 can be greater than the cross-sectional area of the protrusion 311a, which can facilitate the protrusion 311a to be drawn out of the first through-hole 331. This is because the insulating strip 330 is generally a flexible strip. When wrinkling occurs, the first through-hole 331 may be misaligned with the protrusion 311a of the welding strip 311, making it difficult to extend out of the first through-hole 331 of the insulating strip 330.

[0078] In some embodiments, as Figure 8B As shown, the top of the raised portion 311a can be flush with or higher than the surface of the busbar 320 facing away from the insulating strip 330. The top of the raised portion 311a refers to the end of the raised portion 311a facing away from the main body of the welding ribbon 311. When the top of the raised portion 311a is higher than the surface of the busbar 320 facing away from the insulating strip 330, it can ensure that the raised portion 311a has sufficient area to form a reliable welding connection with the busbar 320.

[0079] Figure 11 : is a schematic diagram of a three-dimensional exploded structure of a photovoltaic laminate according to an embodiment of the present utility model. Figure 11 As shown, an exemplary embodiment of the present invention further provides a photovoltaic laminate, including a back cover and a plurality of electrically connected photovoltaic cell strings 310, the photovoltaic cell string 310 being the photovoltaic cell string in the above-mentioned embodiment, the back cover being arranged on the back side of the photovoltaic cell string 310 through an adhesive film, a plurality of recessed portions 500a being formed on the surface of the back cover facing the photovoltaic cell string 310, and at least part of the recessed portions 500a being opposite to the raised portions 311a of the welding strip 311.

[0080] The multiple recessed portions 500a formed on the back cover are opposite to the second through hole 321 of the bus bar 320, that is, opposite to the raised portion 311a on the welding strip 311. Since the top of the raised portion 311a may be higher than the surface of the bus bar 320 facing away from the insulating strip 330, it may cause hidden cracks or breakage of the back cover. Therefore, corresponding recessed portions 500a are provided on the back cover to avoid the raised portion 311a on the welding strip 311, thereby ensuring the reliability of the photovoltaic laminate.

[0081] A photovoltaic laminate consists of five layers of material stacked together. From the light-receiving (front) side to the backlight (back) side, they include a front cover plate 100, a front adhesive film 200, a photovoltaic cell array 300, a back adhesive film 400, and a back cover plate 500. The front cover plate 100 is typically made of tempered glass, offering high light transmittance. The back cover plate 500 can also be made of tempered glass. When both the front cover plate 100 and the back cover plate 500 are made of tempered glass, the resulting module is called a double-glass module. When the back cover plate 500 is a photovoltaic backsheet, the resulting module is called a single-glass module.

[0082] PV backsheets can be made of organic polymer materials, typically composed of multiple layers of materials with different functions, such as polyethylene terephthalate (PET) polyester film, fluorine-containing materials such as polyvinyl formal (PVF) and polyvinylidene difluoride (PVDF), and adhesives. Compared to tempered glass backsheets, PV backsheets are much thinner. Using tempered glass backsheets can improve the sealing, insulation, and resistance to black streaks and hidden cracks in finished PV modules, thereby enhancing their reliability. However, this comes at a relatively high cost.

[0083] The front film 200 and back film 400 can be made of polyethylene vinyl acetate (EVA) film, poly(ethylene-1-octene) (POE) film, EVA / POE laminate, EVA / POE / EVA laminate, or POE / EVA / POE laminate. After the five layers are stacked, they are placed in a laminator. Heat and pressure are applied to melt the front film 200 and back film 400, forming a strong bond between the layers and ultimately forming the finished photovoltaic laminate.

[0084] For example, the insulating strips 330 on the photovoltaic cell string 310 may be one or more of PET film, PET / EVA composite film, EVA / PET / EVA composite film, PET / POE composite film or POE / PET / POE composite film.

[0085] Figure 12 FIG is a schematic diagram of a three-dimensional exploded structure of a photovoltaic laminate according to another embodiment of the present invention. Figure 12As shown, when the back cover is photovoltaic glass, the recessed portion 500a is a groove formed in the glass cover. Since photovoltaic glass is relatively thick, a thinning process can be used to form grooves corresponding to the raised portions 311a on the side of the photovoltaic glass facing the photovoltaic cell string array 300, i.e., there is a one-to-one correspondence between the grooves and the raised portions 311a.

[0086] In an optional embodiment, during the process of forming the groove, in order to facilitate the thinning process, a continuous groove may be formed along the length direction of the bus bar 320 to avoid the protrusion 311 a and / or the bus bar 320 .

[0087] Since the photovoltaic backsheet is made of organic polymer material, it is relatively thin and it is difficult to form the recessed portion 500a by thinning process like photovoltaic glass. When the back cover is a photovoltaic backsheet, the recessed portion 500a may include a groove formed by bending the photovoltaic backsheet, such as Figure 11 shown.

[0088] The photovoltaic backsheet can be bent to form a plurality of continuous grooves, each of which can avoid the raised portion 311a of the welding ribbon 311 and / or the corresponding bus bar 320. The bending process of the photovoltaic backsheet is also relatively simple and low in cost.

[0089] An exemplary embodiment of the present invention further provides a photovoltaic assembly, comprising the photovoltaic laminate of the above embodiment.

[0090] After lamination, the photovoltaic laminate is wrapped around its edges with a protective casing to provide mechanical support and protection. This protective casing is known as the frame or assembly frame, and the photovoltaic laminate, with the frame or assembly frame attached, forms a photovoltaic module.

[0091] The technical advantages of the above-mentioned photovoltaic laminates and photovoltaic modules over the existing technology are the same as the advantages of the above-mentioned photovoltaic cell strings, which will not be repeated here.

[0092] Those skilled in the art will appreciate that the above embodiments are merely intended to clearly illustrate the present invention and are not intended to limit the scope of the present invention. Other variations or modifications may be made based on the above disclosure, and such variations or modifications are still within the scope of the present invention.

Claims

1. A photovoltaic cell string, characterized in that: The invention comprises an insulating strip, a bus bar, a plurality of electrically connected photovoltaic cells, and a plurality of welding strips provided on the photovoltaic cells, wherein the insulating strip is provided on the photovoltaic cells, and the bus bar is provided on a side of the insulating strip away from the photovoltaic cells; A plurality of thin grid lines with opposite polarities are provided on the back of the photovoltaic cell, and the plurality of thin grid lines with opposite polarities are connected to the plurality of welding ribbons in a one-to-one correspondence; The insulating strip has a plurality of first through holes, and each of the plurality of welding strips connected to one of the same polarity fine grid lines has a protrusion, and each of the protrusions passes through the corresponding first through hole and is connected to the bus bar; Each welding strip among the plurality of welding strips connected to another type of fine grid line of the same polarity is electrically isolated from the bus bar by the insulating strip.

2. The photovoltaic cell string according to claim 1, characterized in that: The bus bar has a plurality of second through holes corresponding to the first through holes, and each of the protrusions passes through the corresponding first through hole to the second through hole and is connected to the bus bar.

3. The photovoltaic cell string according to claim 2, characterized in that: An area of a cross section of the first through hole is greater than or equal to an area of a cross section of the second through hole.

4. The photovoltaic cell string according to claim 1, characterized in that: The protrusion is welded to the bus bar; and / or, The protrusion is a tin-coated protrusion; and / or, The busbars and the welding strips are both tin-coated metal strips.

5. The photovoltaic cell string according to any one of claims 1 to 4, characterized in that: The protrusion and the welding strip are integrally formed.

6. The photovoltaic cell string according to claim 5, characterized in that: The protrusion includes a bent structure formed by bending the welding strip; and / or, The raised portion includes a boss structure formed on the welding strip.

7. The photovoltaic cell string according to any one of claims 1 to 4, characterized in that: The top end of the protrusion is flush with or higher than the surface of the bus bar facing away from the insulating strip.

8. A photovoltaic laminate, characterized in that It comprises a back cover plate and a plurality of electrically connected photovoltaic cell strings, wherein the photovoltaic cell string is the photovoltaic cell string according to any one of claims 1 to 7, The back cover is arranged on the back of the photovoltaic cell string through an adhesive film. A plurality of recessed portions are formed on the surface of the back cover facing the photovoltaic cell string. At least part of the recessed portions is opposite to the raised portion of the welding strip.

9. The photovoltaic laminate according to claim 8, characterized in that When the back cover is photovoltaic glass, the recessed portion is a groove opened on the photovoltaic glass.

10. A photovoltaic module, characterized in that: A photovoltaic laminate comprising the photovoltaic laminate according to claim 8 or 9.

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