Battery string

Abstract

The utility model provides a battery string, relates to the field of photovoltaic technology, and solves the technical problem of fragmentation risk caused by unreasonable distribution of bonding pads in the prior art. The device comprises at least two battery piece base bodies welded through a welding strip, the distance between the centers of two bonding pads on the outermost sides of the two adjacent battery piece base bodies is L, the distance between the two side edges, away from each other, of the two adjacent battery piece base bodies is W, the range of L / W is 87%-94%, and the range of W / L is 87%-94%. The lengths of the welding strips connected to the two adjacent battery piece substrates are proper, so that the collection of current carriers and the conduction of current are facilitated; meanwhile, edge subfissure of the cell substrate caused by the fact that the first bonding pad is too close to the edge of the cell substrate can be avoided; and battery piece warping or breaking caused by thermal stress before and after welding of the welding strip can be avoided, so that the battery piece yield and the assembly efficiency are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, in particular to a battery string. Background Art

[0002] Compared with other photovoltaic cells, the positive and negative electrodes of the back-contact cell are both located on the back of the cell, and there is no grid line on the front of the cell, which helps absorb more sunlight and has a higher photoelectric conversion efficiency. Two adjacent cells are connected by a welding ribbon to form a cell string, and the pads used for welding with the welding ribbon are set on the back of the cell. It is precisely because the welding pads and welding ribbons on this type of battery are all set on the back of the cell that there are more welding pads and welding ribbons on the back. During the stretching and welding process of the welding ribbon, the cell string is more likely to have problems such as warping and cold welding. Utility Model Content

[0003] The purpose of the utility model is to provide a battery string, which solves the technical problem of the risk of fragmentation caused by unreasonable distribution of pads in the prior art. The preferred technical solution among the many technical solutions provided by the utility model can produce many technical effects as described below.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] The battery string provided by the utility model comprises at least two battery cell substrates welded by welding strips, the distance between the centers of the two outermost welding pads of two adjacent battery cell substrates is L, the distance between the two side edges of two adjacent battery cell substrates that are far away from each other is W, and the range of L / W is 87% to 94%.

[0006] Preferably, the range of L / W is 91% to 93%.

[0007] Preferably, the battery cell substrate has a first side and a second side perpendicular to each other, and along the second side, the pads include a first pad and a second pad that are sequentially spaced from the first side on both sides to the center; the distance from the first side to the center of the first pad adjacent thereto is S 1 , the distance between the center of the first pad and the center of the second pad adjacent to it is S 2 , the distance between the centers of two adjacent second pads is S 3 ; Among them, S 1 <S 2 <S 3 .

[0008] Optionally, 2S 1 ≥S 3 or 2S 1 <S 3 .

[0009] Optionally, along the second side direction, the second pads are evenly distributed or unevenly distributed.

[0010] Preferably, the cell substrate is a back contact cell.

[0011] Preferably, the length of the welding strip is L 1 , L<L 1 ≤L+5mm.

[0012] Preferably, the number N of the pads of two adjacent battery cell substrates along the second side is 16≤N≤28.

[0013] Preferably, the cell substrate is provided with a plurality of positive polarity collector grid lines and a plurality of negative polarity collector grid lines along the first side direction; the size of the pad along the second side direction is b, and the distance between adjacent collector grid lines of the same polarity is L 2 ;

[0014] 0.5×L 2 ≤b≤3×L 2 .

[0015] Preferably, L 2 The range is 0.5mm~1.2mm; and / or, S 1 >6.5mm.

[0016] This application adopts the above technical solution, which has at least the following beneficial effects:

[0017] The battery string includes at least two battery cell substrates welded by welding strips, the distance between the centers of the two outermost welding pads of two adjacent battery cell substrates is L, the distance between the two side edges of two adjacent battery cell substrates that are far away from each other is W, and the range of L / W is 87% to 94%. This range can make the length of the welding strip connected to the two adjacent battery cell substrates appropriate, which is conducive to the collection of carriers and the conduction of current; at the same time, it can avoid the first welding pad being too close to the edge of the battery cell substrate and causing hidden cracks on the edge of the battery cell substrate; it can also avoid warping or fragmentation of the battery cell caused by thermal stress before and after welding of the welding strip, so as to improve the battery cell yield and component efficiency.

[0018] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the battery string structure provided by an embodiment of the utility model;

[0021] Figure 2 It is a schematic diagram of a local enlarged structure of a battery cell substrate provided in an embodiment of the utility model.

[0022] In the figure, 1 is the first soldering pad; 2 is the second soldering pad; 3 is the soldering strip; 4 is the battery cell substrate; 5 is the first side; 6 is the second side. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the utility model.

[0024] The specific embodiment of the utility model provides a battery string, combined with the attached Figure 1 As shown, at least two cell substrates 4 are welded by welding strips 3, the distance between the centers of the two outermost welding pads of two adjacent cell substrates 4 is L, the distance between the two opposite sides of the adjacent cell substrates 4 is W, and the range of L / W is 87% to 94%. If the L / W ratio is too small, for example, less than 87%, then the length of the welding strip connected to the two adjacent cell substrates is too small, which is not conducive to collecting and transmitting current; if the value of L / W is too large, for example, more than 94%, the first welding pad is too close to the edge of the cell substrate, which is prone to edge cracking of the cell substrate 4, or the cell warping or fragmentation caused by thermal stress before and after welding of the welding strip, thereby reducing the production yield. Therefore, in order to balance the above factors, the present application has studied and obtained a design method in which the distance between the centers of the two outermost welding pads accounts for the distance between the two opposite sides of the two cell substrates, which is in the range of 87% to 94%, which can effectively avoid the risk of warping and fragmentation while ensuring a high current collection efficiency.

[0025] In the more preferred solution of the present application, the range of L / W is 91% to 93%, which further limits the range of L / W, further optimizes the current collection efficiency and avoids the risk of fragmentation.

[0026] The specific L / W can be 87%, 87.1%, 87.2%, 87.3%, 87.4%, 87.5%, 87.6%, 87.7%, 87.8%, 87.9%, 88%, 88.1%, 88.2%, 88.3%, 88.4%, 88.5%, 88.6%, 88.7%, 88.8%, 88.9%, 89%, 89.1%, 89.2%, 89.3%, 89.4%, 89.5%, 89.6%, 89.7%, 89.8%, 89.9%, 90%, 90.1%, 90.2%, 90.3%, 90.4%, 90.5%, 90.6%, 90.7%, 90.8%, 91.9%, 92.1%, 92.2%, 92.3%, 92.4%, 92.5%, 92.6%, 92.7%, 92.8%, 93.9%, 94.1%, 94.2%, 94.3%, 94.4%, 94.5%, 94.6%, 94.7%, 94.8%, 94.9 0.8%, 90.9%, 91%, 91.1%, 91.2%, 91.3%, 91.4%, 91.5%, 91.6%, 91.7%, 91.8%, 91.9%, 92%, 92.1%, 92.2%, 92.3%, 92.4%, 92.5%, 92.6%, 92.7%, 92.8%, 92.9%, 93%, 93.1%, 93.2%, 93.3%, 93.4%, 93.5%, 93.6%, 93.7%, 93.8%, 93.9%, 94%, the layout of the pads with a large proportion combined with the above-mentioned layout form ensures a higher current collection efficiency and a better production yield.

[0027] In a specific embodiment of the present application, the battery cell substrate 4 has a first side 5 and a second side 6 that are perpendicular to each other. Figure 1 As shown in the figure, the first side 5 is the vertical left and right sides, the second side 6 is the horizontal upper and lower sides, and along the second side direction, the pads include the first pads 1 and the second pads 2 which are arranged in sequence from the first sides 5 to the center; the distance from the first side 5 to the center of the first pad 1 adjacent to it is S 1 , the distance between the center of the first pad 1 and the center of the second pad 2 adjacent thereto is S 2 , the distance between the centers of two adjacent second pads 2 is S 3 ; Among them, S 1 <S 2 <S 3 This arrangement indicates that the distance between the three pads near the edge of the cell substrate 4 and the edge position gradually decreases. This method can ensure a high current collection effect at the edge. 2 and S 3 Normally, it is an integer multiple of the collector grid line spacing. In actual situations, the number of collector grid lines cannot be evenly divided at this position, so S 2 Than S 3 A small integer collector grid line spacing, usually S 2 Less than S 3A collector grid line spacing, the collector grid line spacing is the distance between two collector grid lines.

[0028] In the specific embodiment of the present application, 2S 1 ≥S 3， In the specific embodiment of the present application, in 2S 1 =S 3 In the case of ensuring the manufacturing yield and high current collection efficiency, 2S 1 >S 3 Design method, and need to ensure 2S 1 Compared to S 3 It will not be too large, and is generally larger than the spacing of 1 to 10 secondary grids. For example, the layout of the pads on the cell substrate 4 in this application satisfies S 1 ≥(S 2 +k) / 2, 2≤k≤3, where k is the process experience value, in mm, for example, k can be 2mm or 3mm. This setting method aims to ensure the current collection under the premise of ensuring the welding effect. In actual production, if the number of pads is small, S 3 The distance will be larger, and there is 2S 1 <S 3 situation.

[0029] The type of the cell may be a silicon-based cell, a heterojunction cell, or a perovskite cell. The cell is a back contact cell.

[0030] The length of the welding strip 3 in this application is L 1 The soldering strip 3 here is the soldering strip welded on two adjacent battery cells, L<L 1 ≤L+5mm.

[0031] In a specific embodiment of the present application, the number of pads N along the second side of two adjacent battery cell substrates 4 is 16≤N≤28. The arrangement of such a number of pads can avoid the problem of easy bending of the welding ribbon during welding due to excessive spacing, and can also ensure a higher current collection efficiency. For example, the number N can be 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28.

[0032] In a specific embodiment of the present application, along the second side direction, the second pads 2 may be uniformly distributed or non-uniformly distributed; in the case of non-uniform distribution, they may be arranged in a staggered manner with various spacings; they may also be symmetrically distributed or may be other types of distribution.

[0033] In the specific embodiment of the present application, the battery cell substrate 4 is provided with a plurality of positive polarity collector grid lines and a plurality of negative polarity collector grid lines along the first side direction; the size of the pad along the second side direction is b, and the distance between adjacent collector grid lines of the same polarity is L 2 ;

[0034] 0.5×L 2 ≤b≤3×L 2 .

[0035] Specifically, in the second side direction: the size b of the pad is too large, and the number of collector grid lines with different polarities from the pad that need to be interrupted is large, and the dead zone for carrier collection will be larger. It is necessary to set a bending structure for the collector grid lines of opposite polarities to reduce the dead zone, that is, to bend the collector grid lines of opposite polarities at the pad position. However, the above bending structure may cause problems such as poor setting quality, such as poor printing quality. Therefore, 0.5×L 2 ≤b≤3×L 2 , there are fewer dead zones for carrier collection, and the bending structure brings less problems with setting quality, such as printing quality, and the two have achieved a good balance.

[0036] For example, b can be 0.5 times L 2 , 0.53 times L 2 , 0.55 times L 2 , 0.6 times L 2 , 0.65 times L 2 , 0.73 times L 2 , 0.87 times L 2 , 0.93 times L 2 , 1 times L 2 , 1.18 times L 2 , 1.5 times L 2 , 1.86 times L 2 , 2 times L 2 , 2.5 times L 2 , 2.75 times L 2 , 2.84 times L 2 , 3 times L 2 .

[0037] It should be noted that at 0.5×L 2 On the basis of ≤b≤3×L5, in order to facilitate conductive interconnection, in the same back contact cell, in the second side direction, the size b of the first pad 1 adjacent to the edge of the first battery can be larger than the size b of the second pad 2 spaced apart from the first pad 1 in the second side direction, which is further easy to achieve mass production and high production efficiency. The difference between the two is not specifically limited here.

[0038] In some embodiments, L 2The range is 0.5mm~1.2mm. 2 The design scheme is more suitable, which is conducive to the uniform and sufficient collection of carriers and can avoid the waste of materials caused by the over-dense arrangement of adjacent collector grid lines 12 of the same polarity.

[0039] For example, L 2 It can be 0.5mm, 0.55mm, 0.61mm, 0.65mm, 0.68mm, 0.7mm, 0.72mm, 0.75mm, 0.78mm, 0.8mm, 0.85mm, 0.89mm, 0.9mm, 1mm, 1.07mm, 1.15mm, and 1.2mm.

[0040] In some embodiments, S 1 >6.5mm, S 1 In the process of forming a battery string or a photovoltaic module, the position of the first side 5 has a larger conductive interconnection position, such as a welding position, or the reserved operating space is larger, the conductive interconnection is easy to realize mass production, the production efficiency is high, and the distance between the conductive interconnection position and the first battery edge 111 is large, and the risk of hidden cracks is small.

[0041] For example, S 1 It can be 6.51mm, 6.53mm, 6.55mm, 6.59mm, 6.6mm, 6.63mm, 6.67mm, 6.73mm, 6.78mm, 6.8mm, 6.85mm, 6.9mm, 6.95mm, 7mm, and 7.32mm.

[0042] In some embodiments, L 2 The range is 0.5mm~1.2mm, and S 1 >6.5mm; L 2 And can S 1 The above values ​​can be taken.

[0043] The distance between two adjacent battery cell substrates 4 is S 4 , in an ideal state S 4 It can be 0mm. In the actual string welding process, S 4 exist.

[0044] Combined with Figure 1 As shown, S 1 , S 2 , S 3 and 1 、s 2 、s 3 They are located on two rows of main grids. In fact, in the same row of main grids, the left and right sides are symmetrically designed, that is, S 1 =s 1 , S2 =s 2 , S 3 =s 3 .

[0045] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0046] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0047] In the present utility model, the terms "one embodiment", "some embodiments", "examples", "specific examples", "some examples", etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0048] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A battery string, characterized in that: It comprises at least two battery cell substrates welded by welding strips, the distance between the centers of the two outermost welding pads of two adjacent battery cell substrates is L, the distance between the two side edges of two adjacent battery cell substrates that are far away from each other is W, and the range of L / W is 87% to 94%.

2. The battery string according to claim 1, characterized in that: The range of L / W is 91% to 93%.

3. The battery string according to claim 2, characterized in that: The battery cell substrate has a first side and a second side perpendicular to each other. Along the second side, the pads include a first pad and a second pad that are sequentially spaced from the first sides on both sides to the center; the distance from the first side to the center of the first pad adjacent to it is S1, the distance from the center of the first pad to the center of the second pad adjacent to it is S2, and the distance between the centers of two adjacent second pads is S3; Among them, S1<S2<S3.

4. The battery string according to claim 3, characterized in that: 2S1≥S3 or 2S1<S3.

5. The battery string according to claim 3 or 4, characterized in that: Along the second side direction, the second pads are evenly distributed or non-evenly distributed.

6. The battery string according to any one of claims 1 to 4, characterized in that: The cell substrate is a back contact cell.

7. The battery string according to any one of claims 1 to 4, characterized in that: The length of the welding strip is L1, L<L1≤L+5mm.

8. The battery string according to claim 3 or 4, characterized in that: The number N of the pads on two adjacent battery cell substrates along the second side direction is 16≤N≤28.

9. The battery string according to claim 3 or 4, characterized in that: The cell substrate is provided with a plurality of positive polarity collector grid lines and a plurality of negative polarity collector grid lines along the first side direction; the size of the pad along the second side direction is b, and the distance between adjacent collector grid lines of the same polarity is L2; 0.5×L2≤b≤3×L2.

10. The battery string according to claim 9, characterized in that: The range of L2 is 0.5mm~1.2mm; And / or, S1>6.5mm.

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