Back contact battery assembly and photovoltaic system

Abstract

The utility model is suitable for the field of photovoltaic technology, and provides a back contact battery assembly and a photovoltaic system, and the back contact battery assembly comprises a battery string which at least comprises a first battery piece and a second battery piece which are sequentially arranged along a first direction, the first battery piece is arranged at the end part of the battery string, and the second battery piece is arranged at the end part of the battery string. The first welding strip is arranged on the backlight surface of the first battery piece; the second welding strip is arranged on the backlight surface of the second battery piece; the first bus bar is arranged on the backlight face of the second battery piece, the first bus bar can be arranged on the backlight face of the battery piece in a hidden mode, the effective light receiving area of the battery assembly can be increased, the conversion efficiency of the assembly can be improved, and the overall attractiveness of the battery assembly is better; moreover, the first bus bar is arranged on the second battery piece, so that the first welding strip can be ensured to be fully attached to and welded to the effective welding position of the first battery piece.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of photovoltaic technology, and particularly relates to a back contact cell module and a photovoltaic system. BACKGROUND

[0002] In the existing back contact cell module, the series bus bars between adjacent series cell strings are usually placed at the edge of the cell module, and the parallel bus bars between adjacent parallel cell strings are usually placed in the reserved interval area between two cell strings, which results in that a certain space needs to be reserved at the edge of the cell module for placing the series bus bar, and a certain space also needs to be reserved between two parallel cell strings for placing the parallel bus bar. On the one hand, the effective light receiving area of the cell module is reduced, which affects the conversion efficiency of the module. On the other hand, the appearance of the module is affected.

[0003] In some products, the bus bar is installed at the middle position of the back surface of the cell piece, and an insulating strip is arranged between the bus bar and the cell piece. Although this arrangement mode can hide the bus bar, the insulating strip needs to be punched to enable the bus bar to contact the same polarity solder strip on the cell piece and to be insulated from the reverse polarity solder strip on the cell piece. This arrangement mode has high requirements for the punching precision of the insulating strip and the arrangement position precision of the insulating strip, and is difficult to produce. Short circuit or virtual welding is easily caused by position deviation of the insulating strip during punching.

[0004] SUMMARY

[0005] The present application provides a back contact cell module, which aims to solve the problem that the existing insulating strip needs to be punched, the punching precision of the insulating strip and the arrangement position precision of the insulating strip are high, the production is difficult, and short circuit or virtual welding is easily caused by position deviation of the insulating strip during punching.

[0006] The application is implemented as follows: a back contact battery assembly comprises: a battery string, the battery string at least comprising a first battery piece and a second battery piece arranged in sequence along a first direction, the first battery piece being arranged at an end of the battery string, a first solder strip, the first solder strip being arranged on a back surface of the first battery piece; a second solder strip, the second solder strip being arranged on a back surface of the second battery piece; a first bus bar, the first bus bar being arranged on the back surface of the second battery piece; a first insulating strip, the first insulating strip being arranged between the first bus bar and the second battery piece, the first insulating strip being used for isolating the second solder strip and the first bus bar, the first insulating strip and the first bus bar being arranged in extension along a second direction, the first direction and the second direction being arranged in intersection; wherein the first solder strip comprises a main body segment electrically connected to the first battery piece and an extension segment electrically connected to the first bus bar, the extension segment and the second solder strip being arranged in interval in the second direction; the main body segment and the second solder strip being arranged in line in the first direction.

[0007] Optionally, the first solder strip further comprises a connecting segment, the connecting segment being connected between the main body segment and the extension segment.

[0008] Optionally, the main body segment and the connecting segment are connected in smooth transition, and / or the extension segment and the connecting segment are connected in smooth transition.

[0009] Optionally, in the second direction, the connecting segment is arranged in bending relative to the main body segment.

[0010] Optionally, the first solder strip is a plurality of, in the second direction, the connecting segments of the plurality of first solder strips are all arranged in bending towards a first side of the main body segment; or the connecting segments of the plurality of first solder strips are all arranged in bending towards a second side of the main body segment; or a part of the connecting segments of the plurality of first solder strips is arranged in bending towards the first side of the main body segment, and another part of the connecting segments of the plurality of first solder strips is arranged in bending towards the second side of the main body segment, the first side and the second side being opposite.

[0011] Optionally, a bending angle of the connecting segment relative to the main body segment is greater than or equal to 10° and less than or equal to 70°.

[0012] Optionally, the bending angle of the connecting segment relative to the main body segment is greater than or equal to 30° and less than or equal to 60°.

[0013] Optionally, the extension segment and the second solder strip are arranged in parallel.

[0014] Optionally, a distance between the epitaxial segment and the second solder strip satisfies: 1mm≤L1≤1 / 2D, where L1 is a distance between the epitaxial segment and the second solder strip in the second direction, and D is a distance between two adjacent second solder strips.

[0015] Optionally, an extending direction of the epitaxial segment and an extending direction of the second solder strip intersect.

[0016] Optionally, a minimum distance between the epitaxial segment and the second solder strip satisfies: 1mm≤L2≤1 / 2D, where L2 is a minimum distance between the epitaxial segment and the second solder strip in the second direction, and D is a distance between two adjacent second solder strips.

[0017] Optionally, the first battery piece and the second battery piece are arranged on the same plane, and the first battery piece and the second battery piece are arranged with a distance.

[0018] Optionally, a distance between the first battery piece and the second battery piece is greater than or equal to 0 and less than or equal to 3mm.

[0019] Optionally, the first battery piece and the second battery piece are arranged partially overlapped in the first direction.

[0020] Optionally, a partially overlapped distance between the first battery piece and the second battery piece is greater than 0 and less than or equal to 1.5mm.

[0021] Optionally, the back contact battery assembly further comprises a third solder strip, the third solder strip extends from the first battery piece to the second battery piece in the first direction, and the third solder strip connects the first battery piece and the second battery piece.

[0022] Optionally, the third solder strip is a plurality of, and at least one first solder strip and one second solder strip are arranged between two adjacent third solder strips.

[0023] Optionally, the first battery piece is arranged with a first solder point near one end of the second battery piece, and the first solder point is connected with the first solder strip.

[0024] Optionally, the first bus bar is arranged at an end of the second battery piece close to the first battery piece.

[0025] Optionally, the back contact battery assembly comprises at least two groups of battery strings arranged in the second direction, and the first insulating strip extends from one of the two groups of battery strings to the other group of battery strings in the second direction.

[0026] The first bus bar can be hidden on the back surface of the battery piece, so that the effective light receiving area of the battery assembly is increased, the conversion efficiency of the assembly is improved, and the overall appearance of the battery assembly is better. Since the first bus bar is arranged on the second battery piece, the first solder strip can be fully matched and welded with the effective welding position of the first battery piece, so that the welding of the first solder strip and the first battery piece is not insufficient due to the arrangement of the first bus bar, and the collection of current is affected. The first insulating strip is arranged between the second battery piece and the first bus bar during assembly to isolate, the first insulating strip does not need to be punched, and does not need to be arranged discontinuously, which greatly simplifies the processing and installation process of the first insulating strip. At the same time, the first solder strip is arranged to be electrically connected with the first bus bar through the extension section, the extension section and the second solder strip are arranged in the second direction, the first insulating strip can be offset in the first direction during preparation, the production precision requirement and production difficulty are effectively reduced, and the short circuit risk is effectively reduced. In addition, due to the staggered arrangement of the extension section and the second solder strip, the stacking height is reduced, the stress is smaller during lamination, the risk of battery piece cracking and fragmentation is reduced, and the reliability of the back contact battery assembly is good.

[0027] A photovoltaic system comprising the back contact battery assembly described above. The technical effects of the present application are the same as those of the back contact battery assembly described above, and will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic diagram of a first back contact battery assembly provided by the present application;

[0029] Figure 2 is a structural schematic diagram of a second back contact battery assembly provided by the present application;

[0030] Figure 3 is Figure 2 is an enlarged structural schematic diagram of the structure at A of

[0031] Figure 4 is a structural sectional view of the first back contact battery assembly provided by the present application;

[0032] Figure 5 is a structural sectional view of the second back contact battery assembly provided by the present application;

[0033] Figure 6 is a structural schematic diagram of a third back contact battery assembly provided by the present application.

[0034] BRIEF DESCRIPTION OF DRAWINGS

[0035] 100, battery string; 101, first battery piece; 102, second battery piece; 200, first welding strip; 201, main section; 202, extension section; 203, connecting section; 300, second welding strip; 400, first busbar; 500, first insulation strip; 600, third welding strip; 700, first welding spot. DETAILED DESCRIPTION

[0036] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. The examples of the embodiments are shown in the drawings, wherein the same or similar notations denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only and are merely used to explain the present application, and cannot be understood as limiting the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and cannot be used to limit the present application.

[0037] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0038] In addition, the terms "first", "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0039] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] In the present application, unless specifically defined and limited otherwise, "on" or "under" of a first feature with respect to a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "over", "above" and "on" of a first feature with respect to a second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the first feature is higher in horizontal height than the second feature. "Under", "below" and "under" of a first feature with respect to a second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the first feature is lower in horizontal height than the second feature.

[0041] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplification, the components and arrangements of specific examples are described in the following. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to reference numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art can realize the application of other processes and / or the use of other materials.

[0042] As shown in Figure 1 and Figure 2 In an embodiment of the present application, a back contact battery assembly includes a battery string 100, the battery string 100 at least includes a first battery piece 101 and a second battery piece 102 arranged in sequence along a first direction. It can be understood that in the battery string 100, the battery string 100 can include two battery pieces in series, three battery pieces in series or more battery pieces in series, and the number of battery pieces in series can be determined according to actual use, and the present application does not limit the number of battery pieces in series. In addition, the grid lines on the battery pieces are not shown in the drawings, and the grid lines on the battery pieces can be arranged according to actual conditions, for example, the battery pieces can be main grid battery pieces, or the battery pieces can be main grid-free battery pieces. It can be understood that when the battery pieces are main grid battery pieces, a first main grid line is arranged at a position corresponding to the first solder strip on the first battery piece, and a second main grid line corresponding to the second solder strip is arranged at a position corresponding to the second solder strip on the second battery piece; when the battery pieces are main grid-free battery pieces, a corresponding soldering point can be arranged at a position corresponding to the first solder strip on the first battery piece, and a corresponding soldering point can be arranged at a position corresponding to the second solder strip on the second battery piece.

[0043] The first battery piece 101 is arranged at the end of the battery string 100. For the convenience of description, in the embodiment, the end where the first battery piece 101 is arranged is referred to as the tail end of the battery string 100, that is, in the first direction, the first battery piece 101 is the last battery piece of the battery string 100, and the second battery piece 102 is the second last battery piece of the battery string 100. It is understood that the end where the first battery piece 101 is arranged can also be referred to as the head end of the battery string 100, and then the second battery piece 102 is the second battery piece of the battery string 100, which will not be described here. It should be noted that when the first battery piece 101 is arranged at the tail end of the battery string 100, at this time, the first bus bar 400 can be used for series connection between the battery strings 100 adjacent in the second direction; when the first battery piece 101 is arranged at the head end of the battery string 100, at this time, the first bus bar 400 can be used for parallel connection between the battery strings 100 adjacent in the first direction, and at this time the first bus bar is equivalent to the middle bus bar in the battery assembly.

[0044] In some embodiments, the first solder strip 200 is arranged on the back surface of the first battery piece 101, the second solder strip 300 is arranged on the back surface of the second battery piece 102, the first bus bar 400 is arranged on the back surface of the second battery piece 102, and the first insulating strip 500 is arranged between the first bus bar 400 and the second battery piece 102. The first insulating strip 500 is used to isolate the second solder strip 300 and the first bus bar 400, and the first insulating strip 500 and the first bus bar 400 are arranged in extension in the second direction. The first direction and the second direction are arranged in intersection. First, in the embodiment, the first bus bar 400 is arranged on the second battery piece 102, and the first bus bar 400 and the second battery piece 102 are separated by the first insulating strip 500. On the one hand, the edge of the back contact battery assembly does not need to reserve space for placing the bus bar, and the battery assembly can reserve more space for installing the battery piece, so that the effective light receiving area of the battery assembly is larger, and the conversion efficiency of the assembly is higher. On the other hand, from the direction of the light receiving surface (or front surface) of the battery piece, the first insulating strip 500 can shield the first bus bar 400, avoiding the first bus bar 400 from being exposed, and the overall appearance of the battery assembly is better.

[0045] Secondly, compared with the case that the first bus bar 400 is arranged on the back surface of the first battery piece 101, as a possible case, the first solder strip 200 cannot be welded with the first battery piece 101 at the position covered by the first bus bar 400, resulting in insufficient welding between the first solder strip 200 and the first battery piece 101 and poor current collection. In the embodiment of the present application, the first bus bar 400 is arranged on the back surface of the second battery piece 102, and the first solder strip 200 can be fully attached to and welded with the effective welding position of the first battery piece 101, avoiding the installation of the first bus bar 400 to cause insufficient welding between the first solder strip 200 and the first battery piece 101 and affect the collection of current. At the same time, after the first solder strip 200 is welded with the first battery piece 101, it can be directly connected with the first bus bar 400 without the need of opening hole treatment on the insulating strip, and only the first insulating strip 500 needs to be placed on the second battery piece 102 during assembly, effectively reducing the production precision requirement and production difficulty, avoiding short circuit caused by position deviation when the insulating strip is opened, and increasing product yield. Preferably, the first bus bar 400 is arranged at the end of the second battery piece 102 close to the first battery piece 101, so that the extension segment 202 of the first solder strip 200 extends to the edge of the second battery piece 102 close to the first battery piece 101 to realize electrical connection with the first bus bar 400, which can reduce the extension length of the extension segment 202 of the first solder strip 200, save solder strip material, and thus reduce cost. Since the first solder strip 200 needs to be isolated from the second battery piece 102, the width requirement of the first insulating strip 500 is also reduced, and the first insulating strip 500 only needs to be insulated at the edge region of the second battery piece 102.

[0046] In the embodiment of the present application, the first direction is the horizontal direction, which is also the width direction of the battery piece, and the second direction is the vertical direction, which is also the length direction of the battery piece. The first direction and the second direction are perpendicular to each other.

[0047] As Figure 3As shown, in the embodiments of the present application, the first solder strip 200 includes a main body segment 201 electrically connected to the first battery piece 101 and an extension segment 202 electrically connected to the first bus bar 400. In the second direction, the extension segment 202 and the second solder strip 300 are arranged in a spaced manner. In the first direction, the main body segment 201 and the second solder strip 300 are arranged in a collinear manner. That is, the extension segment 202 of the first solder strip 200 is arranged in a staggered manner relative to the main body segment 201 of the first solder strip 200, so that the extension segment 202 extending to the second battery piece 102 does not overlap the second solder strip 300 on the second battery piece 102 in the thickness direction of the first bus bar 400, avoiding the problem of excessive stress caused by the partial overlap of the extension segment 202 and the second solder strip 300 on the first bus bar 400, and reducing the risk of hidden cracking of the battery piece during the lamination process. In the first direction, the main body segment 201 and the second solder strip 300 are arranged in a collinear manner, which can make the wiring of the solder strip more concise and clear, and reduce the wiring difficulty and complexity.

[0048] It can be understood that due to the existing production process, the main body segment 201 and the second solder strip 300 may not be absolutely collinear in the geometric sense. For example, the main body segment 201 and the second solder strip 300 can be staggered within 1mm in the length direction of the first bus bar 400, which can also be considered as collinear. The electrical connection mode can be welding, adhesion through conductive glue, etc., but is not limited thereto.

[0049] The present application can hide the first bus bar on the back surface of the battery piece, which can increase the effective light receiving area of the battery assembly, improve the conversion efficiency of the assembly, and improve the overall aesthetics of the battery assembly. Since the first bus bar is arranged on the second battery piece, the first solder strip can be fully attached and welded to the effective welding position of the first battery piece, avoiding the problem that the arrangement of the first bus bar affects the current collection due to insufficient welding of the first solder strip to the first battery piece. The first insulating strip is arranged between the second battery piece and the first bus bar during assembly to isolate them. The first insulating strip does not need to be punched and arranged, which greatly simplifies the processing and installation process of the first insulating strip. At the same time, by arranging the extension segment of the first solder strip and electrically connecting the first bus bar, the extension segment and the second solder strip are arranged in a spaced manner in the second direction, which can allow the first insulating strip to have a certain degree of deviation in the first direction during the preparation process, effectively reducing the production precision requirement and production difficulty, and effectively reducing the risk of short circuit. Furthermore, due to the staggered arrangement of the extension segment and the second solder strip, the lamination height is reduced, the stress is smaller during lamination, and the risk of battery piece cracking and fragmentation is reduced, and the reliability of the back contact battery assembly is good.

[0050] As Figure 3As shown, the first solder strip 200 further includes a connecting segment 203, which connects the main body segment 201 and the epitaxial segment 202. The connecting segment 203 enables electrical conduction between the main body segment 201 and the epitaxial segment 202, allowing the main body segment 201 to transfer charge carriers on the first solar cell 101 through the connecting segment 203 to the epitaxial segment 202 and then into the first busbar 400, thus completing the collection of charge carriers on the first solar cell 101. Preferably, the main body segment 201 and the connecting segment 203 are smoothly connected, and / or, the epitaxial segment 202 and the connecting segment 203 are smoothly connected. More specifically, in this embodiment, the main body segment 201 and the connecting segment 203 are smoothly connected, and the extension segment 202 and the connecting segment 203 are also smoothly connected. The connecting segment 203 is bent relative to the main body segment 201, and the extension segment 202 is bent relative to the connecting segment 203. This is equivalent to the first welding strip 200 being continuously bent to form the connecting segment 203 and the extension segment 202. The first welding strip 200 is prone to stress concentration at the bending point, and the smooth transition design can effectively disperse these stresses, reducing the risk of the first welding strip 200 breaking or falling off due to stress concentration. The smoothly transitioned connection part has better appearance and can improve the overall visual effect and texture of the product.

[0051] The first welding strip 200, which has a main body segment 201, a connecting segment 203, and an extension segment 202, can be formed by integrally stamping a single welding strip, or it can be formed by splicing multiple welding strips together. This application does not impose any restrictions on this. Preferably, the first welding strip 200 is integrally stamped, which eliminates redundant processes such as welding during the production of the first welding strip 200, reduces labor costs, and avoids phenomena such as incomplete welds and burrs caused by manual welding during the welding process.

[0052] In this embodiment, the connecting segment 203 has a line segment or bend shape. This is not specifically limited in this application; it is sufficient that the extension segment 202 and the second welding strip 300 are spaced apart along the length of the first busbar 400. Preferably, the connecting segment 203 is a straight line segment structure to avoid the strength reduction caused by repeated bending of the welding strip, which could easily lead to breakage or detachment.

[0053] like Figure 4In other embodiments, the first insulating strip 500 is arranged between the first bus bar 400 and the second cell tab 102, and the first insulating strip 500 is used to isolate the second solder strip 300 and the first bus bar 400. Since the first solder strip 200 has a portion extending to the second cell tab 102, it is understood that the first insulating strip 500 is also used to isolate the first solder strip 200 and the second cell tab 102. Specifically, the first insulating strip 500 can be arranged at the end of the second cell tab 102 close to the first cell tab 101. Optionally, the first insulating strip 500 can cover the edges of the second cell tab 102 and the first cell tab 101. This allows the first insulating strip 500 to have a certain degree of offset in the width direction during the manufacturing process relative to the first bus bar 400 and the two cell tabs, thereby reducing the production precision requirement and the production difficulty. On the other hand, it can avoid the short circuit caused by the contact between the first bus bar 400 and the female solder strip / female grid line on the first cell tab 101, and also avoid the short circuit caused by the contact between the first solder strip 200 and the female solder strip / female grid line on the second cell tab 102, as well as the short circuit caused by the conductive foreign matter such as tin residue during the manufacturing process, thereby further reducing the short circuit risk and improving the reliability of the battery assembly.

[0054] In contrast, the first solder strip 200 in the embodiments of the present application can be applied to both the main grid back contact battery assembly and the main grid back contact battery assembly, and has higher universality. Moreover, the first bus bar 400 is arranged at the end of the second cell tab 102 close to the first cell tab 101, which is less stressed than the outer edge of the first cell tab 101 during lamination, thereby reducing the risk of fragmentation and cracking and further improving the reliability of the battery assembly.

[0055] For example, the thickness of the first bus bar 400 can be between 0.06 mm and 0.3 mm, and the width can be between 8 mm and 20 mm. The material of the first bus bar 400 can be a tin-plated copper bus bar, a conductive copper foil, or an aluminum-based copper strip.

[0056] For example, the first insulating strip 500 can be an insulating adhesive, a non-conductive adhesive tape, or an insulating film, such as a PET or PI adhesive tape with acrylic or silicone, or a PET or PI substrate with a single-sided or double-sided film of ethylene-vinyl acetate copolymer or hot melt adhesive. It is understood that the first insulating strip 500 can include ethylene-vinyl acetate copolymer, resin material, polyimide, polypropylene, polyethylene, or other materials, and can also include an acrylic adhesive layer.

[0057] It should be noted that the thickness of the first insulating strip 500 cannot be too thick or too thin. If the first insulating strip 500 is too thin, it is inconvenient to operate when pasting, and it is easy to deform when pulling. Long-term insulation also has the risk of damage. If it is too thick, it will increase the height difference, and the stress generated during the lamination process will be large, which will easily cause fragmentation and increase the risk of false welding. Based on this, in the embodiments of the present application, the thickness of the first insulating strip 500 can be set to between 0.05 millimeters and 0.8 millimeters. In this way, the first insulating strip 500 will neither be too thin nor too thick. For example, the thickness of the first insulating strip 500 can be 0.05 millimeters, 0.1 millimeters, 0.2 millimeters, 0.3 millimeters, 0.4 millimeters, 0.5 millimeters, 0.6 millimeters, 0.7 millimeters, or 0.8 millimeters.

[0058] In the first insulating strip 500, the width of the first insulating strip 500 is greater than or equal to the width of the first bus bar 400. If the width of the first insulating strip 500 is too narrow, the first bus bar 400 will be exposed, and there is a risk that the first bus bar 400 will contact the female electrode area or the female solder strip and cause a short circuit.

[0059] Further, the first solder strip 200 is a plurality of first solder strips 200, and the plurality of first solder strips 200 are arranged on the back surface of the first battery piece 101 in the second direction. The second solder strip 300 is a plurality of second solder strips 300, and the plurality of second solder strips 300 are arranged on the back surface of the second battery piece 102 in the second direction. The plurality of first solder strips 200 and the plurality of second solder strips 300 are arranged one by one.

[0060] In the second direction, the connecting segment 203 is arranged to be bent relative to the main body segment 201. Specifically, an included angle is formed between the main body segment 201 and the connecting segment 203, which defines the bending direction of the connecting segment 203, so that the connecting segment 203 gives way to the second solder strip 300 when bent. The included angle formed between the main body segment 201 and the connecting segment 203 can be selected according to actual needs, and will not be described in detail here.

[0061] Further, the bending angle of the connecting segment 203 relative to the main body segment 201 is greater than or equal to 10° and less than or equal to 70°. Preferably, the bending angle of the connecting segment 203 relative to the main body segment 201 is greater than or equal to 30° and less than or equal to 60°. In such embodiments, the bending angle of the connecting segment 203 relative to the main body segment 201 can be 30°, 40°, 50°, 60°, or any value between 30° and 60°, which is not limited specifically here. When the bending angle of the connecting segment 203 relative to the main body segment 201 is within this range, the metal material of the first solder strip 200 will not reduce its strength due to excessive deformation, and precise processing can be more easily achieved by mechanical or automated equipment. Using a smaller force, the first solder strip 200 can be bent to form the required curvature, improving production efficiency.

[0062] In the embodiments of the present application, the first solder strip 200 is a plurality of first solder strips, and the connecting segments 203 of the plurality of first solder strips 200 are arranged to be bent towards the first side of the main segment 201 in the second direction, or the connecting segments 203 of the plurality of first solder strips 200 are arranged to be bent towards the second side of the main segment 201, or a part of the connecting segments 203 of the plurality of first solder strips 200 are arranged to be bent towards the first side of the main segment 201, and another part of the connecting segments 203 of the plurality of first solder strips 200 are arranged to be bent towards the second side of the main segment 201, and the first side and the second side are opposite. That is, the connecting segments 203 of the plurality of first solder strips 200 can be arranged in the same direction or in different directions relative to the main segment 201, and the bending direction of the connecting segments 203 of the first solder strip 200 relative to the main segment 201 of the first solder strip 200 can be selected according to actual needs to adapt to different processing equipment and production process flows.

[0063] In some embodiments, the epitaxial segment 202 and the second solder strip 300 are arranged in parallel. In this way, the epitaxial segment 202 and the second solder strip 300 can be independent of each other in the extension direction, and even if the length of the epitaxial segment 202 is relatively long, the epitaxial segment 202 and the second solder strip 300 can be arranged to be non-overlapping and dispersed in the thickness direction of the first bus bar 400, thereby avoiding the local stress concentration of the battery module and causing the hidden cracks of the battery piece. Preferably, the interval distance L1 between the epitaxial segment 202 and the second solder strip 300 satisfies 1mm≤L1≤1 / 2D, where L1 is the interval distance between the epitaxial segment 202 and the second solder strip 300 in the second direction, and D is the interval between two adjacent second solder strips 300. When the interval distance between the epitaxial segment 202 and the second solder strip 300 is within this range, it can be ensured that the epitaxial segment 202 and the second solder strip 300 are completely non-coincident or completely non-overlapping in the length direction of the first bus bar 400, thereby achieving the effect of dispersing the local stress of the battery module.

[0064] In some embodiments, the extension direction of the epitaxial segment 202 and the extension direction of the second solder strip 300 intersect. That is, the extension direction of the epitaxial segment 202 can be flexibly arranged, and the extension direction of the epitaxial segment 202 can be flexibly adjusted according to actual needs during the processing and installation process of the first solder strip 200, thereby achieving the interval between the epitaxial segment 202 and the second solder strip 300. Preferably, the minimum interval distance L2 between the epitaxial segment 202 and the second solder strip 300 satisfies 1mm≤L2≤1 / 2D, where L2 is the minimum interval distance between the epitaxial segment 202 and the second solder strip 300 in the second direction, and D is the interval between two adjacent second solder strips 300. When the minimum interval distance between the epitaxial segment 202 and the second solder strip 300 is within this range, it can be ensured that the epitaxial segment 202 and the second solder strip 300 are completely non-coincident or completely non-overlapping in the length direction of the first bus bar 400, thereby achieving the effect of dispersing the local stress of the battery module.

[0065] In some embodiments, the first battery piece 101 and the second battery piece 102 are arranged on the same plane and are spaced apart. In this way, a buffer space is provided between the battery pieces, so that the battery pieces will not be damaged by contacting each other when the battery assembly is subjected to external force.

[0066] Specifically, the spacing distance between the first battery piece 101 and the second battery piece 102 is greater than or equal to 0 and less than or equal to 3 mm. In such embodiments, the spacing distance between the first battery piece 101 and the second battery piece 102 can be 0 mm, 1 mm, 2 mm, 3 mm, or any value between 0 and 3 mm, which is not limited herein. Within this range, the risk of combining the battery pieces is reduced, while the overall length of the battery string 100 is prevented from being too long, and the stability of the connection between adjacent battery pieces is improved.

[0067] In some embodiments, in the first direction, the first battery piece 101 and the second battery piece 102 are arranged partially overlapping. The contact area between the overlapping parts is not conductively connected, i.e., no conductive adhesive or other adhesive is needed between the overlapping parts, and the battery pieces are simply overlapped. In this way, there is no gap between the first battery piece 101 and the second battery piece 102, so that the series welding band can be better hidden, and there is no need to set a shielding insulating layer in the gap between the battery pieces to hide the series welding band, thereby reducing the use of the shielding insulating layer, reducing production costs, and making it easier to repair. In addition, by overlapping the battery pieces, the size of the battery string 100 can be reduced, thereby reducing the occupied space of the battery string 100. Alternatively, in the case of a certain size of the battery string 100, more battery pieces can be placed, the power of the battery string 100 is improved, and the cost per watt is reduced. Preferably, the partial overlapping distance between the first battery piece 101 and the second battery piece 102 is greater than 0 and less than or equal to 1.5 mm. Exemplarily, the overlapping width range can be 0 mm, 0.1 mm, 0.2 mm, 0.4 mm, 0.5 mm, 1 mm, or 1.5 mm, which is not limited herein.

[0068] As Figure 5As shown, the back contact battery assembly further includes a third solder ribbon 600 extending from the first cell tab 101 to the second cell tab 102 along the first direction, the third solder ribbon 600 connecting the first cell tab 101 and the second cell tab 102. Specifically, a portion of the third solder ribbon 600 is disposed on the first cell tab 101, and another portion of the third solder ribbon 600 is disposed on the second cell tab 102. Exemplarily, the third solder ribbon 600 can be used to realize a series connection between the first cell tab 101 and the second cell tab 102. Understandably, the extension segment 202 of the first solder ribbon 200 and the other portion of the third solder ribbon 600 disposed on the second cell tab 102 are not overlapped, and are arranged at intervals along the length direction of the first bus bar 400, so as to realize a local stress dispersion effect of the battery assembly. Further, the portion of the third solder ribbon 600 disposed on the second cell tab 102 is isolated by the first insulating strip 500 and the first bus bar 400. In the embodiment of the present application, the third solder ribbon 600 is a plurality of, and at least one first solder ribbon 200 and one second solder ribbon 300 are arranged between any two adjacent third solder ribbons 600, so as to realize uniform distribution of current on the cell tab.

[0069] In some embodiments, the first cell tab 101 is provided with a first soldering point 700 close to one end of the second cell tab 102, and the first soldering point 700 is connected with the first solder ribbon 200. Understandably, the first soldering point 700 is located at the edge of the first cell tab 101 closest to the second cell tab 102 (i.e., the connection point of the most edge of the first solder ribbon 200 on the first cell tab 101), and the first soldering point 700 can be a grid line or a solder pad, so as to realize sufficient collection of charge carriers on the first cell tab and improve the stability of the connection between the first solder ribbon 200 and the first cell tab 101.

[0070] As shown, Figure 6 In some embodiments, the back contact battery assembly includes at least two groups of cell strings 100 arranged along the second direction, and the first insulating strip 500 extends from one of the two groups of cell strings to the other along the second direction. In this way, the first insulating strip 500 can be laid once between at least two adjacent groups of cell strings, so as to simplify the assembly steps of the battery assembly and improve the production efficiency of the battery assembly. Understandably, the back contact battery assembly includes a plurality of groups of cell strings, and the first insulating strip can be laid once for the plurality of groups of cell strings. For example, the back contact battery assembly includes three groups of cell strings, and the first insulating strip can extend from the first group of cell strings to the third group of cell strings.

[0071] A photovoltaic system comprising the back contact cell assembly as described above. It can be understood that the photovoltaic power generation system comprises at least one back contact cell assembly as described above, and it can be understood that the back contact cell assemblies can be electrically connected in parallel or in series, which can be selected and arranged according to actual needs. In the embodiment, the photovoltaic system can be applied in a photovoltaic power station, such as a ground power station, a roof power station, a water surface power station, etc., and can also be applied in a device or apparatus that generates power by using solar energy, such as a user solar power source, a solar street lamp, a solar car, a solar building, etc. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is, the photovoltaic system can be applied in all fields that need to generate power by using solar energy. Taking a photovoltaic power generation system network as an example, the photovoltaic system can comprise a photovoltaic array, a combiner box and an inverter, the photovoltaic array can be an array combination of a plurality of cell assemblies, for example, a plurality of cell assemblies can form a plurality of photovoltaic arrays, the photovoltaic arrays are connected to the combiner box, the combiner box can combine the currents generated by the photovoltaic arrays, the combined currents flow through the inverter to convert into alternating current required by a power grid, and then the alternating current is connected to a power network to realize solar power supply.

[0072] In the description of the present specification, the description of the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0073] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A back contact cell assembly, characterized by, The battery string comprises at least a first battery piece and a second battery piece arranged in sequence along a first direction, the first battery piece is arranged at an end of the battery string, a first welding strip is arranged on a back surface of the first battery piece, a second welding strip is arranged on a back surface of the second battery piece, a first bus bar is arranged on the back surface of the second battery piece, a first insulating strip is arranged between the first bus bar and the second battery piece, the first insulating strip is used to isolate the second welding strip and the first bus bar, the first insulating strip and the first bus bar are arranged in extension along a second direction, the first direction and the second direction are arranged in intersection, the first welding strip comprises an extension segment electrically connected to a main segment of the first battery piece and an extension segment electrically connected to the first bus bar, in the second direction, the extension segment and the second welding strip are arranged in interval, in the first direction, the main segment and the second welding strip are arranged in collineation. The first welding strip further comprises a connecting segment connected between the main segment and the extension segment.

2. The back contact solar cell assembly of claim 1, wherein, The main segment and the connecting segment are connected in smooth transition, and / or the extension segment and the connecting segment are connected in smooth transition.

3. The back contact solar cell assembly of claim 2, wherein, In the second direction, the connecting segment is arranged in bending relative to the main segment.

4. The back contact solar cell assembly of claim 2, wherein the back contact solar cell assembly is a back contact solar cell module. The first welding strip is a plurality of, in the second direction, the connecting segments of the plurality of first welding strips are arranged in bending towards a first side of the main segment, or the connecting segments of the plurality of first welding strips are arranged in bending towards a second side of the main segment, or a part of the connecting segments of the plurality of first welding strips are arranged in bending towards the first side of the main segment, and another part of the connecting segments of the plurality of first welding strips are arranged in bending towards the second side of the main segment, the first side and the second side are opposite.

5. The back contact solar cell assembly of claim 4, wherein the back contact solar cell assembly is a back contact solar cell module. The bending angle of the connecting segment relative to the main segment is greater than or equal to 10° and less than or equal to 70°.

6. The back contact solar cell assembly of claim 4, wherein the back contact solar cell assembly is a back contact solar cell module. The bending angle of the connecting segment relative to the main segment is greater than or equal to 30° and less than or equal to 60°.

7. The back contact solar cell assembly of claim 4, wherein the back contact solar cell assembly is a back contact solar cell module. The extension segment and the second welding strip are arranged in parallel.

8. The back contact solar cell assembly of claim 1 wherein, The interval distance of the extension segment and the second welding strip satisfies 1mm≤L1≤1 / 2D, wherein L1 is the interval distance of the extension segment and the second welding strip in the second direction, and D is the interval distance between adjacent two second welding strips.

9. The back contact solar cell assembly of claim 8, wherein, The extension direction of the extension segment and the extension direction of the second welding strip are in intersection.

10. The back contact solar cell assembly of claim 1 wherein, The minimum interval distance of the extension segment and the second welding strip satisfies 1mm≤L2≤1 / 2D, wherein L2 is the minimum interval distance of the extension segment and the second welding strip in the second direction, and D is the interval distance between adjacent two second welding strips.

11. The back contact solar cell assembly of claim 10, wherein the back contact solar cell assembly is a back contact solar cell module. The first battery piece and the second battery piece are arranged on the same plane, and the first battery piece and the second battery piece are arranged in interval.

12. The back contact solar cell assembly of claim 1 wherein, The interval distance of the first battery piece and the second battery piece is greater than or equal to 0 and less than or equal to 3mm.

13. The back contact solar cell assembly of claim 12, wherein the back contact solar cell assembly is a back contact solar cell module. ​ 14. The back contact solar cell assembly of claim 1 wherein, In the first direction, the first cell piece and the second cell piece are partially overlapped.

15. The back contact solar cell assembly of claim 14, wherein the back contact solar cell assembly is a back contact solar cell module. The first cell piece and the second cell piece are partially overlapped by a distance greater than 0 and less than or equal to 1.5 mm.

16. The back contact solar cell assembly of claim 1 wherein, The back contact cell assembly further comprises a third solder ribbon, along the first direction, the third solder ribbon extends from the first cell piece to the second cell piece, the third solder ribbon connects the first cell piece and the second cell piece.

17. The back contact solar cell assembly of claim 1 wherein, The third solder ribbon is a plurality of, between any two adjacent third solder ribbons, at least one first solder ribbon and one second solder ribbon are arranged.

18. The back contact solar cell assembly of claim 1 wherein, The first cell piece is provided with a first soldering point near one end of the second cell piece, the first soldering point is connected with the first solder ribbon.

19. The back contact solar cell assembly of claim 1 wherein, The first bus bar is arranged at the end of the second cell piece close to the first cell piece.

20. The back contact solar cell assembly of claim 1 wherein, The back contact cell assembly comprises at least two groups of cell strings arranged along the second direction, along the second direction, the first insulating strip extends from one of the two groups of cell strings to the other group of cell strings.

21. A photovoltaic system characterized by, The back contact cell assembly comprises at least two groups of cell strings arranged along the second direction, along the second direction, the first insulating strip extends from one of the two groups of cell strings to the other group of cell strings. The back contact cell assembly comprises at least two groups of cell strings arranged along the second direction, along the second direction, the first insulating strip extends from one of the two groups of cell strings to the other group of cell strings.

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