Main-grid-free back contact battery, battery assembly and photovoltaic system

Abstract

The utility model provides a main-grid-free back contact battery, a battery assembly and a photovoltaic system. The main-grid-free back contact battery comprises a battery substrate; the fine grids are arranged on the battery substrate; the distance between each first fixing section and the first edge is smaller than the distance between the first fixing section and the second edge in the first direction; the first fixed section comprises a plurality of first welding spot parts which are arranged at intervals in the first direction, the first welding spot parts are arranged on the fine grids, and the areas of at least part of the first welding spot parts in the plurality of first welding spot parts are gradually reduced in the first direction; the battery substrate further comprises a plurality of conductive adhesive areas, the conductive adhesive areas are used for arranging conductive adhesives, and in the second direction, the conductive adhesive areas and the first fixing section are arranged at intervals. Due to the arrangement of the first fixed section and the conductive adhesive region, the welding strip is prevented from being aligned with the central positions of welding spots on the battery pieces one by one during arrangement, and the arrangement difficulty of the welding strip is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to photovoltaic technology field especially relates to a kind of main gridless back contact cell, battery pack and photovoltaic system. BACKGROUND

[0002] In battery pack, adjacent cell piece is connected by welding band.In related technology, in order to prevent welding band from deviating, welding band needs to be aligned with the center position of soldering point on cell piece one by one when setting welding band.This makes the setting difficulty of welding band greater.

[0003] Therefore, how to reduce the setting difficulty of welding band has become a problem to be solved. UTILITY MODEL CONTENT

[0004] The utility model provides a kind of main gridless back contact cell, battery pack and photovoltaic system to solve the technical problem of how to reduce the setting difficulty of welding band.

[0005] The utility model embodiment is realized as follows, the utility model provides a kind of main gridless back contact cell, battery pack and photovoltaic system.A kind of main gridless back contact cell, comprising: cell substrate, the cell substrate includes the first edge and the second edge along the first direction arrangement, the first edge and the second edge are oppositely arranged;Several thin grids, set in the cell substrate, the thin grid along the first direction arrangement, the thin grid extends along the second direction, the first direction and the second direction intersect, the first direction is the direction from the first edge to the second edge;Several first fixed sections, along the first direction, the distance of each first fixed section to the first edge is less than the distance of the first fixed section to the second edge;The first fixed section includes the first soldering point part along the first direction interval arrangement, the first soldering point part is set in the thin grid, and the area of at least part of the first soldering point part in multiple first soldering point parts gradually decreases along the first direction;The cell substrate further includes several conductive glue areas, and the conductive glue area is used to set conductive glue, and in the second direction, the conductive glue area is spaced apart from the first fixed section.Further, along the first direction, the area of all the first soldering point part in multiple first soldering point parts gradually decreases.

[0006] Further, along the first direction, the area of all the first soldering point part in multiple first soldering point parts gradually decreases.

[0007] Further, along the first direction, the size of at least part of the first soldering point part in multiple first soldering point parts gradually decreases in the second direction.

[0008] Further, along the first direction, the size of all the first soldering point part in multiple first soldering point parts gradually decreases in the second direction.

[0009] Further, along the first direction, the difference between the sizes of the two adjacent first solder point portions in the second direction is 0.05mm to 0.15mm.

[0010] Further, in at least one of the first fixed segments, along the first direction, the area of the first solder point portion first decreases and then increases.

[0011] Further, along the first direction, the center point of each first solder point portion in the first fixed segment is on a first straight line, and the first straight line extends along the first direction.

[0012] Further, along the first direction, the connecting line of the center points of all first solder point portions in the two adjacent first fixed segments is a first fold line.

[0013] Further, the first fold line comprises a plurality of straight line segments.

[0014] Further, the back contact cell without main grid further comprises a second solder point portion; in the first direction, the center point of the second solder point portion is located between two adjacent first fixed segments; in the second direction, the center point of the second solder point portion is located between two first straight lines formed by two adjacent first fixed segments; the two side edges of the second solder point portion in the second direction do not comprise the conductive adhesive area.

[0015] Further, the back contact cell without main grid further comprises a plurality of first soldering segments, and the first soldering segments and the first fixed segments are arranged in sequence along the first direction; the edge of the first soldering segment in the second direction does not comprise the conductive adhesive area; the first soldering segment comprises a plurality of third solder point portions arranged on the fine grid, and along the first direction, the area of the third solder point portion gradually decreases.

[0016] Further, the back contact cell without main grid further comprises a second soldering segment, and the first soldering segment, the first fixed segment and the second soldering segment are arranged in sequence along the first direction; the edge of the second soldering segment in the second direction does not comprise the conductive adhesive area; the second soldering segment comprises a plurality of fourth solder point portions arranged on the fine grid, and along the first direction, the area of the fourth solder point portion gradually decreases.

[0017] Further, the area of the third solder point portion with the smallest area is greater than or equal to the area of the fourth solder point portion with the largest area.

[0018] Further, the area of the fourth solder point portion with the largest area is less than or equal to the area of the first solder point portion with the smallest area.

[0019] Further, the first solder point part comprises a first boundary line, and the first boundary line of each first solder point part in the first fixed segment is on a second straight line extending along the first direction.

[0020] The utility model embodiment further provides a battery assembly, the battery assembly includes the no main grid back contact battery that above described.

[0021] Further, the battery assembly further comprises a solder strip and conductive glue, the solder strip is connected with the fine grid through the conductive glue and solder point part, and the conductive glue is arranged in the conductive glue area; the solder point part comprises at least one of a plurality of first solder point parts, a plurality of second solder point parts, a plurality of third solder point parts and a plurality of fourth solder point parts.

[0022] Further, the solder strip covers the solder point part and the conductive glue.

[0023] Further, the solder point part comprises a first edge point, the first edge point is the point on the solder point part farthest from the conductive glue area in the second direction; the conductive glue area comprises a second edge point, the second edge point is the point on the conductive glue area farthest from the solder point part in the second direction; in the second direction, the interval between the first edge point and the second edge point is a first size; in the second direction, the width of the solder strip is a second size; the second size is greater than or equal to the first size.

[0024] The utility model embodiment further provides a photovoltaic system, the photovoltaic system includes the battery assembly as described above.

[0025] The no main grid back contact battery in the utility model embodiment can be positioned by the conductive glue area when the solder strip is arranged, so that the solder strip is prevented from deviating, and then the solder point part in the first fixed segment is welded, so that the solder strip needs not to be aligned with the center position of the solder point on the battery piece one by one when arranged, and the difficulty of arranging the solder strip is reduced. Meanwhile, the area of at least part of the first solder point part in the plurality of first solder point parts gradually decreases along the first direction, so that the tensile force of the solder strip at the edge part of the no main grid back contact battery can be increased, the firmness of the solder strip welding can be improved, the solder strip welding is stabilized, and the risk of virtual welding of the solder strip is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0027] Figure 1 is a module schematic diagram of a photovoltaic system provided by an embodiment of the present application;

[0028] Figure 2 is a module schematic diagram of a battery assembly provided by an embodiment of the present application;

[0029] Figure 3 is a schematic diagram of a back contact cell without main grid provided by an embodiment of the present application;

[0030] Figure 4 is a partial structure schematic diagram of a back contact cell without main grid provided by an embodiment of the present application;

[0031] Figure 5 is a partial structure schematic diagram of a back contact cell without main grid provided by another embodiment of the present application;

[0032] Figure 6 is a partial structure schematic diagram of a back contact cell without main grid provided by still another embodiment of the present application;

[0033] Figure 7 is a partial structure schematic diagram of a back contact cell without main grid provided by yet another embodiment of the present application;

[0034] Figure 8 is a partial structure schematic diagram of a back contact cell without main grid provided by still another embodiment of the present application;

[0035] Figure 9 is a partial structure schematic diagram of a back contact cell without main grid provided by still another embodiment of the present application;

[0036] Figure 10 is a partial structure schematic diagram of a back contact cell without main grid provided by still another embodiment of the present application;

[0037] Figure 11 is a partial structure schematic diagram of a back contact cell without main grid provided by still another embodiment of the present application;

[0038] Figure 12 is a partial structure schematic diagram of a back contact cell without main grid provided by still another embodiment of the present application;

[0039] Figure 13 is a part structure schematic view of a battery assembly provided by another embodiment of the utility model.

[0040] Main element symbol explanation: 1000, photovoltaic system;1001, battery assembly;100, back contact cell without main grid;200, solder strip;300, conductive glue;10, battery substrate;11, first edge;12, second edge;13, conductive glue area;20, fine grid;30, first fixed section;40, solder point part;50, first soldering section;60, second soldering section;70, second fixed section;41, first solder point part;42, second solder point part;43, third solder point part;44, fourth solder point part;131, second edge point;401, first edge point;411, first boundary line;71, first straight line;72, first fold line;73, second straight line;721, straight line section. DETAILED DESCRIPTION

[0041] In order to make the utility model's purpose, technical scheme and advantage more clearly, the following is combined with the embodiment, and the utility model is further detailed. The embodiment described below by referring to the drawings is exemplary, and is only used for explaining the utility model, and cannot be understood as the limitation of the utility model. In addition, it should be understood that the specific embodiment described here is only used to explain the utility model, and is not used to limit the utility model.

[0042] In the description of the utility model, it should be understood that the orientation or position relationship indicated by the terms "length", "width", "upper", "lower", "top", "bottom", "transverse", "longitudinal" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model.

[0043] In addition, the terms "first", "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more of the features. In the description of the utility model, the meaning of "multiple" is two or more than two, unless otherwise specifically limited.

[0044] In the description of the utility model, it is necessary to explain, unless there is definite stipulation and limitation, the term "installation", "link", "connection" should be broad sense understanding, for example, can be fixed connection, also can be detachable connection, or integrally connected, can be mechanical connection, also can be electrical connection or can communicate with each other, can be directly connected, also can be indirectly connected through intermediate medium, can be the intercommunication of two elements or the interaction of two elements. For ordinary skilled in the art, the specific meaning of the above-mentioned terms in the utility model can be understood according to the specific situation.

[0045] The following disclosure provides many different embodiments or examples for implementing different structures of the utility model. In order to simplify the disclosure of the utility model, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the utility model. In addition, the utility model can refer to the same reference numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, which does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the utility model provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0046] Please refer to Figure 1 And Figure 2 The photovoltaic system 1000 in the embodiment of the utility model can include the battery assembly 1001 in the embodiment of the utility model, and the battery assembly 1001 in the embodiment of the utility model can include a plurality of main gridless back contact cells 100. The plurality of main gridless back contact cells 100 can be sequentially connected in series through the welding strip 200 to form a battery string. Each battery string in the battery assembly 1001 can be connected in series, parallel, or a combination of series and parallel to realize the current output of the bus, for example, the connection between each battery string can be realized through the bus bar.

[0047] As Figures 3 to 12 Indicated, the main gridless back contact cell 100 in the embodiment of the utility model includes: a battery substrate 10, a plurality of fine grids 20, and a plurality of first fixed sections 30. The battery substrate 10 includes a first edge 11 and a second edge 12 arranged along a first direction, and the first edge 11 and the second edge 12 are oppositely arranged. The plurality of fine grids 20 are arranged on the back surface of the battery substrate 10, the fine grids 20 are arranged along the first direction, the fine grids 20 extend along the second direction, the first direction and the second direction intersect, and the first direction is from the first edge 11 to the second edge 12.

[0048] Exemplarily, the battery substrate 10 can include a silicon substrate, and can also include a dielectric layer, a doped layer, a passivation layer, etc., which can be set according to actual conditions.

[0049] AsFigure 3 , Figure 4 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 and Figure 12 As shown. Along the first direction, the distance from each first fixed segment 30 to the first edge 11 is less than the distance from the first fixed segment 30 to the second edge 12; the first fixed segment 30 includes a plurality of first solder joints 41 spaced apart along the first direction, the first solder joints 41 being disposed on the fine grid 20, and the area of ​​at least a portion of the plurality of first solder joints 41 gradually decreasing along the first direction of the battery substrate.

[0050] The battery substrate 10 also includes several conductive adhesive regions 13, which are used to apply conductive adhesive 300. In the second direction, the conductive adhesive regions 13 are spaced apart from the first fixed section 30.

[0051] The gridless back contact battery 100 in this embodiment of the present invention has a first fixing section 30 and a conductive adhesive area 13. When setting the solder ribbon 200, the conductive adhesive area 13 can be used to position the solder ribbon 200 to prevent it from shifting. Then, the first solder joint 41 in the first fixing section 30 is used for welding. This avoids the need to align the solder ribbon 200 with the center position of the solder joint on the battery cell one by one when setting it, thus reducing the difficulty of setting the solder ribbon 200.

[0052] Meanwhile, the area of ​​at least a portion of the first solder joints 41 gradually decreases along the first direction, which can increase the tension of the solder strip 200 at the edge of the back contact battery 100 without a main grid, improve the strength of the solder strip 200 welding, stabilize the solder strip 200 welding, and reduce the risk of solder strip 200 poor soldering.

[0053] Specifically, the gridless back-contact solar cell 100 can be a single, continuous cell, or it can be a half-cell, a third-cell, or other proportioned cell divided from a single continuous cell. To make the accompanying drawings clearer, Figure 3 The gridless back contact battery 100 shown can be exemplarily a half cell divided from a single battery cell. Figures 4 to 12 The diagram shows a portion of the gridless back contact battery 100; the other areas of the gridless back contact battery 100 are similar to... Figures 4 to 12 Similarly, you can refer to this. Figures 4 to 12 This will not be elaborated further here. In other words, the attached diagram is only an example and does not represent a limitation on the specific form of the gridless back contact battery 100.

[0054] Specifically, the back side of the battery substrate 10 has two types of fine grids 20 with alternating polarities, which can be positive electrode grids 20 and negative electrode grids 20, respectively.

[0055] Further, the battery substrate 10 includes a front surface and a back surface, the front surface faces the sun and mainly receives the direct sunlight, and the back surface faces the mounting surface of the battery assembly 1001, such as the ground, the roof, etc. Alternatively, the back surface is the surface provided with the grid lines of the back contact battery 100.

[0056] Further, the staggered distribution means that one negative fine grid 20 is arranged between two adjacent positive fine grids 20, and one positive fine grid 20 is arranged between two adjacent negative fine grids 20.

[0057] Specifically, the back contact battery 100 has a first fixed section 30 and a conductive glue area 13. The first fixed section 30 and the conductive glue area 13 are matched to set the solder strip 200. The first fixed section 30 includes a plurality of first soldering point parts 41, which can be PAD points, soldering points or solder pads. Solder paste can be arranged on the first soldering point parts 41 to realize the welding of the first soldering point parts 41 and the solder strip 200.

[0058] The conductive glue area 13 is arranged corresponding to the first fixed section 30. The conductive glue area 13 is used to set the conductive glue 300. When the solder strip 200 is set, the conductive glue 300 can be arranged on the conductive glue area 13. In this way, the conductive glue 300 can be used to position in advance when the solder strip 200 is set. At the same time, the solder strip 200 is fixed by the conductive glue 300 and the first soldering point parts 41 at the same time, which can also improve the stability of the conductive connection between the solder strip 200 and the fine grid 20, and prevent the solder strip 200 from being falsely soldered.

[0059] Further, the conductive glue area 13 is specifically arranged spaced apart from the first fixed section 30 in the second direction. In this way, when the conductive glue 300 is set, the conductive glue 300 can avoid contaminating the first soldering point parts 41 and affecting the welding effect of the first soldering point parts 41.

[0060] Specifically, as shown in Figures 3 to 12 the first direction and the second direction can be the longitudinal direction and the transverse direction of the back contact battery 100, of course, in other embodiments, the first direction and the second direction can also be other directions, for example, the two can be diagonal directions of the battery substrate 10, which is not limited specifically herein.

[0061] Specifically, as shown in Figures 3 to 12 the first direction is the same as the direction in which the first edge 11 of the battery substrate 10 faces the center of the battery substrate 10.

[0062] Specifically, for the specific structure of the battery substrate 10, the battery substrate 10 has a first edge 11 and a second edge 12, the first edge 11 and the second edge 12 are arranged along the first direction, and both extend along the second direction.

[0063] It can be understood that the first edge 11 and the second edge 12 are two opposite edge lines of the battery substrate 10, or in other words, the first edge 11 and the second edge 12 are two opposite boundary lines of the battery substrate 10. In the embodiment of the utility model, the center of the battery substrate 10 can be understood as the geometric center of the battery substrate 10, or as the center line of the battery piece.

[0064] Specifically, in the first direction, the distance from the first fixed section 30 to the first edge 11 is less than the distance from the first fixed section 30 to the second edge 12. Therefore, in the first direction, the first fixed section 30 is closer to the first edge 11.

[0065] It is worth noting that "the area of at least part of the plurality of first solder point parts 41 gradually decreases in the first direction". It means that in the first fixed section 30, there are at least two first solder point parts 41 that satisfy: the area of the first solder point part 41 gradually decreases in the first direction. Or in other words, at least two first solder point parts 41 satisfy: in the first direction, the closer to the first edge 11, the larger the area of the first solder point part 41, and the farther away from the first edge 11, the smaller the area of the first solder point part 41.

[0066] It can be understood that "at least part" can mean that the area of each first solder point part 41 in the first fixed section 30 gradually decreases in the first direction. It can also mean that the area of part of the first solder point part 41 in the first fixed section 30 gradually decreases in the first direction.

[0067] It can be understood that in the back contact battery without main grid 100, the stress is more concentrated in the edge part, so the soldering force of the solder strip 200 in this part is insufficient, and false welding is prone to occur. And the closer to the edge of the back contact battery without main grid 100, the stronger the stress, the more difficult it is to stably weld the solder strip 200, and the more likely it is to cause false welding.

[0068] And in the embodiment of the utility model, the area of at least part of the plurality of first solder point parts 41 gradually decreases in the first direction. Further, the area of the first solder point part 41 close to the first edge 11 of the back contact battery without main grid 100 can be increased to increase the soldering force of the solder strip 200 and the fine grid 20 in the edge part of the back contact battery without main grid 100, so as to improve the soldering force of the solder strip 200 in the edge part of the back contact battery without main grid 100, improve the firmness of the soldering of the solder strip 200, and reduce the risk of false welding of the solder strip 200.

[0069] Specifically, the overall external profile of the first fixed section 30 can be set as a trapezoidal shape, an arc shape, or the like. When the overall external profile of the first fixed section is a trapezoidal shape, optionally, the external profile of the first fixed section 30 can be a trapezoidal shape with the short side away from the first edge 11 and the long side close to the first edge 11.

[0070] Referring to Figure 4 and Figures 6 to 12 In some embodiments, along the first direction, the area of all the first solder joint portions 41 in the plurality of first solder joint portions 41 gradually decreases. In this way, the tensile force of the solder ribbon 200 of the edge portion of the back contact cell 100 without a main grid can be further increased, the firmness of the solder ribbon 200 welding can be improved, the solder ribbon 200 welding can be stabilized, and the risk of solder ribbon 200 false welding can be reduced to disperse and resist the stress that gradually increases as the back contact cell 100 without a main grid gets closer to the first edge 11, so as to improve the tensile force of the solder ribbon 200 of the edge portion, improve the firmness of the solder ribbon 200 welding, stabilize the solder ribbon 200 welding, and reduce the risk of solder ribbon 200 false welding.

[0071] At the same time, by gradually reducing the area of the first solder joint portion 41, the use of materials can be optimized and the cost of setting can be reduced under the premise of ensuring the strength of the solder ribbon 200 welding.

[0072] For the gradually decreasing area of the first solder joint portion 41, there can be various cases, for example, there are 6 first solder joint portions 41 arranged in sequence along the first direction, and the areas of the first solder joint portions 41 are X1, X2, X3, X4, X5, and X6 in sequence. X1>X2>X3>X4>X5>X6 can be used to make the area of the first solder joint portion 41 gradually decrease, or X1=X2>X3=X4>X5=X6 can also be used to make the area of the first solder joint portion 41 gradually decrease, which is not limited here.

[0073] In some embodiments, along the first direction, the size of at least some of the first solder joint portions 41 in the plurality of first solder joint portions 41 in the second direction gradually decreases.

[0074] It is worth noting that "the size of at least some of the first solder joint portions 41 in the plurality of first solder joint portions 41 in the second direction gradually decreases along the first direction". This means that in the first fixed section 30, there are at least two first solder joint portions 41 that satisfy that the size of the first solder joint portion 41 in the second direction gradually decreases along the first direction. In other words, at least two first solder joint portions 41 satisfy that in the first direction, the size of the first solder joint portion 41 in the second direction gets larger as it gets closer to the first edge 11, and gets smaller as it gets farther away from the first edge 11.

[0075] It can be understood that "at least partially" can mean that the size of each first soldering point part 41 in the first fixed section 30 in the second direction gradually decreases along the first direction. It can also mean that the size of a part of the first soldering point part 41 in the first fixed section 30 in the second direction gradually decreases along the first direction.

[0076] Specifically, in the back contact cell without busbar 100, the stress is more concentrated in the edge part, so the tensile force of the solder strip 200 welded in this part is insufficient, and false welding is prone to occur. And the closer to the edge of the back contact cell without busbar 100, the stronger the stress, the more difficult it is to stably weld the solder strip 200, and the more prone to false welding.

[0077] In the embodiment of the utility model, the size of at least part of the first soldering point part 41 in the plurality of first soldering point parts 41 in the second direction gradually decreases along the first direction. Further, the area of the first soldering point part 41 close to the first edge 11 of the back contact cell without busbar 100 can be increased to increase the welding tensile force of the solder strip 200 and the fine grid 20 in the edge part of the back contact cell without busbar 100, so as to improve the welding tensile force of the solder strip 200 in the edge part of the back contact cell without busbar 100, improve the firmness of the solder strip 200 welding, and reduce the risk of false welding of the solder strip 200.

[0078] Please refer to Figure 4 And Figures 6 to 12 In some embodiments, along the first direction, the size of all first soldering point parts 41 in the plurality of first soldering point parts 41 in the second direction gradually decreases. In this way, the tensile force of the solder strip 200 in the edge part of the back contact cell without busbar 100 can be further increased, the firmness of the solder strip 200 welding can be improved, the solder strip 200 welding can be stabilized, the risk of false welding of the solder strip 200 can be reduced, the stress of the back contact cell without busbar 100 gradually increasing closer to the first edge 11 can be dispersed and resisted, the tensile force of the solder strip 200 in the edge part can be improved, the firmness of the solder strip 200 welding can be improved, the solder strip 200 welding can be stabilized, and the risk of false welding of the solder strip 200 can be reduced.

[0079] At the same time, by gradually reducing the size of the first soldering point part 41 in the second direction, the use of materials can be optimized and the cost of setting can be reduced under the premise of ensuring the welding strength of the solder strip 200.

[0080] Please refer to Figure 7In some embodiments, along the first direction, the difference D1 between the lengths of two adjacent first soldering point portions 41 in the second direction is 0.05mm to 0.15mm. For example, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.10mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm. In this way, the difference between the lengths of two adjacent first soldering point portions 41 in the second direction is within the above range, which can avoid the difference between the lengths of two adjacent first soldering point portions 41 in the second direction being too large, reduce the variation range of the soldering tension of two adjacent first soldering point portions 41, and thus reduce the probability of the battery piece being warped.

[0081] It can be understood that, along the first direction, the difference D1 between the sizes of two adjacent first soldering point portions 41 in the second direction is greater than 0. That is, the closer to the first edge 11, the larger the size of the first soldering point portion 41 in the second direction.

[0082] For the arrangement of the first soldering point portions 41 in the first fixed section 30, as shown in Figure 5 In some embodiments, in at least one first fixed section 30, along the first direction, the area of the first soldering point portion 41 first decreases and then increases. For example, in the second direction, the area of the first soldering point portion 41 on the same fine grid as the conductive adhesive area 13 can be smaller, and the area of the first soldering point portion 41 not on the same fine grid as the conductive adhesive area 13 can be larger, so as to reduce the probability of the conductive adhesive 300 being printed to the first soldering point portion 41, and thus improve the soldering effect. It can be understood that “at least one first fixed section 30” means that one or more first soldering point portions 40 in the first fixed section 30 can satisfy that, along the first direction, the area of the first soldering point portion 41 first decreases and then increases.

[0083] Please refer to Figure 9 In some embodiments, along the first direction, the center point of each first soldering point portion 41 in the first fixed section 30 is on the first straight line 71, and the first straight line 71 extends along the first direction. In this way, the soldering precision when the solder strip 200 is soldered with each first soldering point portion 41 can be improved; during soldering, the arrangement of the solder strip 200 can be offset, and if the center point of each first soldering point portion 41 in the first fixed section 30 is on the first straight line 71, even if the arrangement of the solder strip 200 is offset, the contact area between the solder strip 200 and the first soldering point portion 41 can be large enough, so as to improve the soldering effect.

[0084] It can be understood that the center point of each first soldering point part 41 in the first fixed section 30 is on the first straight line 71, that is, the center points of the plurality of first soldering point parts 41 are flush, so that the solder strip 200 can be more accurately aligned with each first soldering point part 41 when laid, thereby improving the welding accuracy and stability of the solder strip 200.

[0085] Referring to Figure 5 In some embodiments, the first soldering point part 40 includes a first boundary line 411 extending in the first direction, and in the first direction, the first boundary line 411 of each first soldering point part 41 in the first fixed section 30 is on the second straight line 73 extending in the first direction. In this way, the welding accuracy when the solder strip 200 is welded with each first soldering point part 41 can be improved.

[0086] It can be understood that the first boundary line 411 of each first soldering point part 41 in the first fixed section 30 is on the second straight line 73, that is, the plurality of first boundary lines 411 are flush, so that the solder strip 200 can be more accurately aligned with each first soldering point part 41 when laid, thereby improving the welding accuracy and stability of the solder strip 200.

[0087] Referring to Figure 11 In some embodiments, the number of the first fixed sections 30 is a plurality, and in the first direction, the connecting line of the center points of all the first soldering point parts 41 in the two adjacent first fixed sections 30 is the first fold line 72. In this way, during the welding of the solder strip 200, the solder paste can be arranged on the first soldering point part 41, and the conductive adhesive 300 can be arranged on the conductive adhesive area 13, and the conductive adhesive 300 can be staggered, thereby improving the pre-fixing effect of the solder strip 200.

[0088] It can be understood that the connecting line of the center points of all the first soldering point parts 41 in the two adjacent first fixed sections 30 is the first fold line 72, which can increase the distance between the conductive adhesive area 13 and the first fixed section 30 spaced from the conductive adhesive area 13. Even if the height of the conductive adhesive 300 is higher than the height of the solder paste on the first soldering point part 41, the farther distance between them can effectively avoid the occurrence of virtual welding in the subsequent welding process, and at the same time, the adhesion of the conductive adhesive area 13 to the solder strip 200 can be guaranteed, thereby ensuring the stability of the pre-fixing of the solder strip 200. Specifically, the first fold line 72 includes a plurality of straight line segments 721. The straight line segment 721 corresponds to the first fixed section 30.

[0089] In addition, in some embodiments, the connecting line of the center points of all the first soldering point parts 41 in the adjacent first fixed sections 30 can also be in other forms, for example, the connecting line of the center points of all the first soldering point parts 41 in the two adjacent first fixed sections 30 can also be a wavy line, that is, in the first direction, the arrangement profile of the first soldering point part 41 is wavy, which is not limited here.

[0090] Please see Figure 4 and Figure 6 In some embodiments, the gridless back contact battery 100 further includes a second solder joint portion 42. In a first direction, the center point of the second solder joint portion 42 is located between two adjacent first fixing segments 30. In a second direction, the center point of the second solder joint portion 42 is located between two first straight lines 71 formed by two adjacent first fixing segments 30. In other words, the center point of the second solder joint portion 42 is not on the line connecting the center points of the first solder joint portions 41 included in any of the first fixing segments 30 adjacent to the second solder joint portion 42. The conductive adhesive area 13 is not included on both sides of the second solder joint portion 42 along the second direction. Thus, by providing the second solder joint portion 42 between two adjacent first fixing segments 30, the transition between the two adjacent first fixing segments 30 can be made smoother, thereby reducing welding stress and reducing the probability of cell warping.

[0091] It is worth noting that the number of second solder joints 42 can be one or more. The second solder joint 42 is located between two adjacent first fixed segments 30 in the first and second directions. The conductive adhesive area 13 is not included on either side of the second solder joint 42 along the second direction; that is, the conductive adhesive area 13 avoids the side edges of the second solder joint 42 along the second direction. When conductive adhesive 300 is provided, it is not provided on either side of the second solder joint 42 along the second direction. This reduces the interference of the conductive adhesive 300 on the soldering process, thereby ensuring the accuracy and stability of the soldering process.

[0092] Specifically, the second solder joint 42 can be a PAD point, a solder joint, or a solder pad. Solder paste can be applied to the second solder joint 42 to achieve soldering between the second solder joint 42 and the solder ribbon 200.

[0093] Please see Figure 12 In some embodiments, the gridless back contact battery 100 further includes a plurality of first welding segments 50, the first welding segments 50 and the first fixing segments 30 being arranged sequentially along a first direction; the edges of the first welding segments 50 along a second direction do not include conductive adhesive areas 13; the first welding segments 50 include a plurality of third solder joints 43 disposed on the fine grid 20, the third solder joints 43 being arranged at intervals along the first direction. Along the first direction, the area of ​​the third solder joints 43 gradually decreases. In this way, while ensuring a stable connection of the solder strip 200, the amount of conductive adhesive 300 used can be reduced, achieving the effect of cost saving. At the same time, the tensile strength of the solder strip 200 at the edge of the gridless back contact battery 100 can be further increased, improving the weld strength of the solder strip 200, stabilizing the solder strip 200 weld, and reducing the risk of poor soldering of the solder strip 200.

[0094] It can be understood that the edge of the first welding section 50 along the second direction does not include the conductive adhesive area 13, that is, the conductive adhesive area 13 avoids the two side edges of the first welding section 50 along the second direction, or in other words, the two side edges of the first welding section 50 along the second direction are not provided with the conductive adhesive area 13. Further, when the conductive adhesive 300 is arranged, the conductive adhesive 300 can be arranged only near the first fixed section 30 to reduce the amount of conductive adhesive 300 and save costs.

[0095] Meanwhile, the first welding section 50 and the first fixed section 30 are arranged in sequence along the first direction. That is, the first welding section 50 is closer to the first edge 11 than the first fixed section 30. The first welding section 50 includes a plurality of third soldering point portions 43 arranged on the fine grid 20, and the area of the third soldering point portion 43 gradually decreases along the first direction. Thus, the tensile force of the solder strip 200 of the edge portion of the back contact cell 100 without a main grid can be further increased, the firmness of the soldering of the solder strip 200 can be improved, the soldering of the solder strip 200 can be stabilized, and the risk of false welding of the solder strip 200 can be reduced to disperse and resist the stress that gradually increases as the back contact cell 100 without a main grid is closer to the first edge 11, so as to improve the tensile force of the solder strip 200 of the edge portion, improve the firmness of the soldering of the solder strip 200, stabilize the soldering of the solder strip 200, and reduce the risk of false welding of the solder strip 200.

[0096] Please refer to Figure 12 In some embodiments, the back contact cell 100 without a main grid further includes a second welding section 60, the first welding section 50, the first fixed section 30 and the second welding section 60 are arranged in sequence along the first direction; the edge of the second welding section 60 along the second direction does not include the conductive adhesive area 13; the second welding section 60 includes a plurality of fourth soldering point portions 44 arranged on the fine grid 20, and the fourth soldering point portions 44 are arranged in sequence along the first direction. The area of the fourth soldering point portion 44 gradually decreases along the first direction.

[0097] In this way, while ensuring stable connection of the solder strip 200, the amount of conductive adhesive 300 can be reduced to save costs. Meanwhile, the tensile force of the solder strip 200 of the edge portion of the back contact cell 100 without a main grid can be further increased, the firmness of the soldering of the solder strip 200 can be improved, the soldering of the solder strip 200 can be stabilized, and the risk of false welding of the solder strip 200 can be reduced.

[0098] It can be understood that the edge of the second welding section 60 along the second direction does not include the conductive adhesive area 13, that is, the conductive adhesive area 13 avoids the two side edges of the second welding section 60 along the second direction, or in other words, the two side edges of the second welding section 60 along the second direction are not provided with the conductive adhesive area 13. Further, when the conductive adhesive 300 is arranged, the conductive adhesive 300 can be arranged only near the first fixed section 30 to reduce the amount of conductive adhesive 300 and save costs.

[0099] Meanwhile, the first soldering section 50, the first fixing section 30 and the second soldering section 60 are arranged in sequence along the first direction. The second soldering section 60 comprises a plurality of fourth soldering point portions 44 arranged on the fine grid 20, and the area of the fourth soldering point portion 44 gradually decreases along the first direction. Thus, the tensile force of the solder strip 200 at the edge portion of the back contact cell 100 without busbars can be further increased, the soldering firmness of the solder strip 200 can be improved, the soldering of the solder strip 200 can be stabilized, and the risk of false welding of the solder strip 200 can be reduced, so as to disperse and resist the stress gradually increasing as the back contact cell 100 without busbars is closer to the first edge 11, so as to improve the tensile force of the solder strip 200 at the edge portion, improve the soldering firmness of the solder strip 200, stabilize the soldering of the solder strip 200, and reduce the risk of false welding of the solder strip 200.

[0100] Specifically, the third soldering point portion 43 and the fourth soldering point portion 44 can be PAD points, soldering points or soldering pads. Solder paste can be arranged on the third soldering point portion 43 and the fourth soldering point portion 44 to realize the soldering of the third soldering point portion 43 and the fourth soldering point portion 44 with the solder strip 200.

[0101] Specifically, the area of the third soldering point portion 43 with the smallest area is greater than or equal to the area of the fourth soldering point portion 44 with the largest area. In this way, the soldering point portions 40 in the first soldering section 50 and the second soldering section 60 for soldering with the solder strip 200 can have a trend of gradually decreasing in area in the first direction as a whole. Thus, the stress gradually increasing as the back contact cell 100 without busbars is closer to the edge can be dispersed and resisted, so as to improve the tensile force of the solder strip 200 at the edge portion of the back contact cell 100 without busbars, improve the soldering firmness of the solder strip 200, stabilize the soldering of the solder strip 200, and reduce the risk of false welding of the solder strip 200. Meanwhile, the use of materials can be optimized and the cost can be reduced under the premise of ensuring the soldering strength of the solder strip 200.

[0102] Specifically, the area of the fourth soldering point portion 44 with the largest area is equal to or less than the area of the first soldering point portion 41 with the smallest area. In this way, the soldering point portions 40 in the first fixing section 30 and the second soldering section 60 for soldering with the solder strip 200 can have a trend of gradually decreasing in area in the first direction as a whole. Thus, the stress gradually increasing as the back contact cell 100 without busbars is closer to the edge can be dispersed and resisted, so as to improve the tensile force of the solder strip 200 at the edge portion of the back contact cell 100 without busbars, improve the soldering firmness of the solder strip 200, stabilize the soldering of the solder strip 200, and reduce the risk of false welding of the solder strip 200. Meanwhile, the use of materials can be optimized and the cost can be reduced under the premise of ensuring the soldering strength of the solder strip 200.

[0103] Please refer to Figure 1In a possible implementation, the back contact cell without main grid 100 in the embodiment of the utility model can further include a second fixed section 70, the distance from the second fixed section 70 to the second edge 12 is less than the distance from the second fixed section 70 to the first edge 11 along the first direction;The second fixed section 70 includes a plurality of first soldering point parts 41 arranged at intervals along the first direction, the first soldering point part 41 is arranged in the thin grid 20, and the area of at least part of the first soldering point part 41 in the plurality of first soldering point parts 41 gradually increases along the first direction.In the second direction, the conductive adhesive area 13 is arranged at intervals with the second fixed section 70.

[0104] The back contact cell without main grid 100 in the embodiment of the utility model, because of being provided with the second fixed section 70 and the conductive adhesive area 13, then when setting the solder strip 200, the solder strip 200 can be positioned through the conductive adhesive area 13, the solder strip 200 is prevented from deviating, and then welding is carried out through the first soldering point part 41 in the second fixed section 70, so that the center position of the soldering point on the cell piece needs to be aligned one by one when setting the solder strip 200 is avoided, and the setting difficulty of the solder strip 200 is reduced.

[0105] Meanwhile, the area of at least part of the first soldering point part 41 in the plurality of first soldering point parts 41 gradually decreases along the first direction, and then the tensile force of the solder strip 200 at the edge part of the back contact cell without main grid 100 can be increased, the firmness of the solder strip 200 welding is improved, the solder strip 200 welding is stabilized, and the risk of virtual welding of the solder strip 200 is reduced.

[0106] It can be understood that the arrangement mode and overall structure of each first soldering point part 41 in the second fixed section 70 can refer to the first fixed section 30, which will not be repeated here.

[0107] In addition, in a possible implementation, the back contact cell without main grid 100 in the embodiment of the utility model can further include a plurality of fifth soldering point parts 45, as shown in the figure, the fifth soldering point part 45 is arranged near the middle line of the back contact cell without main grid 100, and the area of the plurality of fifth soldering point parts 45 is unchanged along the first direction.And the area of the fifth soldering point part 45 is less than or equal to the area of the first soldering point part 41 with the smallest area in the first fixed section 30. Figure 3

[0108] Thus, the setting of the fifth soldering point part 45 can provide a stable welding area for the middle part of the back contact cell without main grid 100, ensure that the middle part of the back contact cell without main grid 100 has uniform mechanical strength and stability, and also achieve the effect of optimizing the use of materials and reducing costs.

[0109] Please refer to Figure 13 For the battery assembly 1001 provided by the utility model embodiment, the battery assembly 1001 includes the back contact cell without main grid 100 described above. ​

[0110] Please refer to Figure 13 In some embodiments, the battery assembly 1001 further comprises a solder strip 200 and a conductive adhesive 300, the solder strip 200 is connected with the fine grid 20 through the conductive adhesive 300 and the soldering point part 40, the conductive adhesive 300 is arranged in the conductive adhesive area 13; the soldering point part 40 comprises at least one of a plurality of first soldering point parts 41, a plurality of second soldering point parts 42, a plurality of third soldering point parts 43, a plurality of fourth soldering point parts 44 and a fifth soldering point part 45. In this way, when the solder strip 200 is arranged, the solder strip 200 can be positioned through the conductive adhesive 300 to prevent the solder strip 200 from deviating, and then welded through the soldering point part 40, so as to avoid the need to align the center positions of the soldering points on the battery sheet one by one when the solder strip 200 is arranged, thereby reducing the difficulty of arranging the solder strip 200.

[0111] At the same time, by fixing the solder strip 200 through the conductive adhesive 300 and the soldering point part 40 at the same time, the stability of the conductive connection between the solder strip 200 and the fine grid 20 can be improved, and the virtual welding of the solder strip 200 can be prevented.

[0112] Please refer to Figure 13 In some embodiments, the solder strip 200 covers the soldering point part 40 and the conductive adhesive 300. In this way, stable connection of the solder strip 200 and the fine grid 20 can be achieved.

[0113] It can be understood that "the solder strip 200 covers the soldering point part 40 and the conductive adhesive 300" means that the solder strip 200 partially covers the soldering point part 40 and the solder strip 200 partially covers the conductive adhesive 300. It can also mean that the solder strip 200 partially covers the soldering point part 40 and the solder strip 200 completely covers the conductive adhesive 300. It can also mean that the solder strip 200 completely covers the soldering point part 40 and the solder strip 200 partially covers the conductive adhesive 300. It can also mean that the solder strip 200 completely covers the soldering point part 40 and the solder strip 200 completely covers the conductive adhesive 300. This is not limited here.

[0114] Optionally, the solder strip 200 can be arranged to completely cover the soldering point part 40. In this way, the soldering point part 40 can be prevented from being exposed, thereby preventing the soldering point part 40 from being contaminated, affecting the connection effect of the soldering point part 40 and the solder strip 200, and even short-circuiting the soldering point part 40.

[0115] Optionally, the solder strip 200 can be arranged to completely cover the conductive adhesive 300. In this way, the conductivity and connection stability of the solder strip 200 can be improved.

[0116] Please refer to Figure 13 In some embodiments, the soldering point part 40 comprises a first edge point 401, the first edge point 401 being a point on the soldering point part 40 farthest from the conductive adhesive area 13 in a second direction; the conductive adhesive area 13 comprises a second edge point 131, the second edge point 131 being a point on the conductive adhesive area 13 farthest from the soldering point part 40 in the second direction.

[0117] In the second direction, the distance between the first edge point 401 and the second edge point 131 is a first size D2; in the second direction, the width of the solder strip 200 is a second size D3; the second size D3 is greater than or equal to the first size D2. In this way, the solder strip 200 can completely cover the solder point part 40 while ensuring the conductivity and connection stability of the solder strip 200, avoiding the exposure of the solder point part 40, thereby avoiding the pollution of the solder point part 40, affecting the connection effect of the solder point part 40 and the solder strip 200, and even short-circuiting the solder point part 40.

[0118] It can be understood that the first edge point 401 refers to the point on the solder point part 40 that is farthest from the conductive adhesive area 13 in the second direction. Specifically, the first edge point 401 is located at the edge of the solder point part 40 away from the conductive adhesive area 13.

[0119] It can be understood that the second edge point 131 refers to the point on the conductive adhesive area 13 that is farthest from the solder point part 40 in the second direction. Specifically, the second edge point 131 is located at the edge of the solder point part 40 away from the conductive adhesive area 13.

[0120] It can be understood that in such embodiments, the battery assembly 1001 can further include a frame, a back plate, photovoltaic glass, and a film. The film can be filled between the front and back of the cell sheet, photovoltaic glass, adjacent cell sheets, etc., as a filler, which can be a transparent adhesive with good light transmission performance and aging resistance, for example, the film can use EVA film or POE film, which can be selected according to actual conditions, which is not limited here.

[0121] The photovoltaic glass can be covered on the film on the front of the cell sheet, and the photovoltaic glass can be super white glass, which has high light transmittance, high transparency, and has superior physical, mechanical and optical properties, for example, the light transmittance of super white glass can reach more than 92%, which can protect the cell sheet as much as possible without affecting the efficiency of the cell sheet. At the same time, the film can bond the photovoltaic glass and the cell sheet together, and the presence of the film can seal and insulate the cell sheet and prevent water and moisture.

[0122] The back plate can be attached to the film on the back of the cell sheet, and the back plate can protect and support the cell sheet, has reliable insulation, water resistance and aging resistance, the back plate can have multiple choices, usually can be tempered glass, organic glass, aluminum alloy TPT composite film, etc., which can be set according to the specific circumstances, which is not limited here. The whole composed of the back plate, the cell sheet, the film and the photovoltaic glass can be set on the frame, and the frame as the main external support structure of the whole battery assembly 1001 can stably support and install the battery assembly 1001, for example, the battery assembly 1001 can be installed at the desired installation position through the frame.

[0123] In the description of the application, reference to terms "some embodiments", "certain embodiments", "an example", "a specific example" or "some examples" etc. means that a particular feature, structure, material or characteristic being described is included in at least one embodiment or example of the application. The appearances of the above terms in various places in the specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0124] In addition, the above descriptions are only the preferred embodiments of the present application, not intended to limit the present application, and 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 with no busbars, characterized in that, The application relates to a back contact battery without main grid, comprising: a battery substrate, which comprises a first edge and a second edge arranged along a first direction, and the first edge and the second edge are oppositely arranged; a plurality of fine grids arranged on the battery substrate, the fine grids are arranged along the first direction, and the fine grids extend along a second direction, the first direction and the second direction intersect, and the first direction is a direction from the first edge to the second edge; a plurality of first fixed sections along the first direction, the distance from each first fixed section to the first edge is less than the distance from the first fixed section to the second edge; the first fixed section comprises a plurality of first soldering point parts arranged along the first direction, the first soldering point parts are arranged on the fine grids, and the area of at least part of the first soldering point parts gradually decreases along the first direction; the battery substrate further comprises a plurality of conductive glue areas for arranging conductive glue, and the conductive glue areas are arranged in the second direction and are spaced apart from the first fixed section.

2. The no-lead back-contact cell of claim 1, wherein, Along the first direction, the area of all the first soldering point parts gradually decreases.

3. The gridless back contact cell of claim 1, wherein, Along the first direction, the size of at least part of the first soldering point parts in the second direction gradually decreases.

4. The eni -main grid back contact cell of claim 3, wherein, Along the first direction, the size of all the first soldering point parts in the second direction gradually decreases.

5. The eni -main grid back contact cell of claim 1, wherein, Along the first direction, the size difference between two adjacent first soldering point parts in the second direction is 0.05mm to 0.15mm.

6. The gridless back contact cell of claim 1, wherein, In at least one first fixed section, along the first direction, the area of the first soldering point part first decreases and then increases.

7. The gridless back contact cell of claim 1 wherein, Along the first direction, the center point of each first soldering point part in the first fixed section is on a first straight line, and the first straight line extends along the first direction.

8. The gridless back contact cell of claim 1, wherein, Along the first direction, the connecting line of the center points of all the first soldering point parts in two adjacent first fixed sections is a first fold line.

9. The eni -main grid back contact cell of claim 8, wherein, The first fold line comprises a plurality of straight line sections.

10. The eni -main grid back contact cell of claim 7, wherein, The back contact battery without main grid further comprises a second soldering point part; In the first direction, the center point of the second soldering point part is located between two adjacent first fixed sections; In the second direction, the center point of the second soldering point part is located between two first straight lines formed by two adjacent first fixed sections; The two side edges of the second soldering point part along the second direction do not comprise the conductive glue area.

11. The gridless back-contact cell of claim 1, wherein, The back contact battery without main grid further comprises a plurality of first welding sections, and the first welding sections and the first fixed sections are arranged along the first direction in sequence; The edge of the first welding section along the second direction does not comprise the conductive glue area; The first welding section comprises a plurality of third soldering point parts arranged on the fine grids, and the area of the third soldering point parts gradually decreases along the first direction.

12. The eni -main grid back contact cell of claim 11, wherein, The back contact battery without main grid further comprises a second welding section, and the first welding section, the first fixed section and the second welding section are arranged along the first direction in sequence; The edge of the second welding section along the second direction does not comprise the conductive glue area; The second soldering section includes a plurality of fourth soldering points arranged in the fine grid, and the area of the fourth soldering points gradually decreases along the first direction.

13. The eni -main grid back contact cell of claim 12, wherein, The area of the third soldering point with the smallest area is greater than or equal to the area of the fourth soldering point with the largest area.

14. The eni -main grid back contact ceU of claim 12, wherein, The area of the fourth soldering point with the largest area is less than or equal to the area of the first soldering point with the smallest area.

15. The gridless back contact cell of claim 1, wherein, The first soldering section includes a first boundary line, and the first boundary line of each first soldering point in the first fixed section is on a second straight line extending along the first direction.

16. A battery assembly characterized by, The battery assembly includes the back contact cell without busbar as claimed in any one of claims 1 to 15.

17. The battery assembly of claim 16, wherein, The battery assembly further includes a solder strip and conductive adhesive, the solder strip is connected with the fine grid through the conductive adhesive and soldering points, and the conductive adhesive is arranged in the conductive adhesive area. The soldering points include at least one of a plurality of first soldering points, a plurality of second soldering points, a plurality of third soldering points, and a plurality of fourth soldering points.

18. The battery assembly of claim 17, wherein, The solder strip covers the soldering points and the conductive adhesive.

19. The battery assembly of claim 17, wherein, The soldering points include a first edge point, which is the point on the soldering points farthest from the conductive adhesive area in the second direction. The conductive adhesive area includes a second edge point, which is the point on the conductive adhesive area farthest from the soldering points in the second direction. In the second direction, the distance between the first edge point and the second edge point is a first size. In the second direction, the width of the solder strip is a second size. The second size is greater than or equal to the first size.

20. A photovoltaic system characterized by, The battery assembly includes the battery assembly as claimed in any one of claims 16 to 19.

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