Solar cell, cell string and photovoltaic module

Abstract

The utility model provides a solar cell, a cell string and a photovoltaic assembly. The solar cell piece comprises a joint part arranged on at least one surface of the cell piece, the joint part is used for being connected with an external interconnection strip, and the joint part is configured to be of a rectangular structure with chamfers; wherein the joint part is provided with a first edge extending in the first direction and a second edge extending in the second direction, and the first direction intersects with the second direction; one end of the first edge is connected with the second edge through a chamfer, the interconnection strip extends in the second direction, and the ratio of the first width of the joint part in the first direction to the width of the chamfer in the first direction is 2-6. The cell string comprises a plurality of solar cells and interconnection strips. The photovoltaic module comprises at least one battery piece.

Description

Technical Field

[0001] At least one embodiment of the utility model relates to the field of photovoltaic technology, and in particular to a solar cell, a battery string and a photovoltaic module. Background Art

[0002] In photovoltaic modules, the connection between cells is mainly achieved by welding the joints to the interconnecting bars, wherein the joints are the main connection points and are suitable for providing excellent weldability for the interconnecting bars.

[0003] To meet different welding requirements, the joint can be designed and printed into various sizes and shapes. The area of ​​the joint printed based on the above design determines the consumption of materials required to prepare the joint. That is, the larger the area of ​​the joint is under the premise of consistent thickness, the more material consumption is required to print the joint.

[0004] Taking the joint made of silver as an example, the larger the area of ​​the joint, the more silver paste is required, which increases the manufacturing cost of the joint. Therefore, how to make the joint have a smaller overall area on the basis of meeting the design requirements of the effective welding area has become a technical problem that needs to be solved urgently. Utility Model Content

[0005] To solve at least one of the above and other technical problems in the prior art, the utility model provides a solar cell, a battery string and a photovoltaic module, which reduce the overall area of ​​the joint by designing a rectangular structure joint with chamfered corners.

[0006] An embodiment of the utility model provides a solar cell sheet, comprising a joint portion arranged on at least one surface of the cell sheet, the joint portion being used to connect to an external interconnection strip, and the joint portion being configured as a rectangular structure with a chamfer; wherein the joint portion has a first side extending along a first direction and a second side extending along a second direction, and the first direction intersects with the second direction; one end of the first side is connected to the second side by a chamfer, the interconnection strip extends along the second direction, and a ratio of a first width of the joint portion along the first direction to a width of the chamfer along the first direction is between 2 and 6.

[0007] According to an embodiment of the present invention, the solar cell sheet further includes a third side extending along the second direction, and the other end of the first side is also connected to the third side through a chamfer.

[0008] According to an embodiment of the present invention, the length of the first side is configured to be greater than or equal to 500 micrometers and less than or equal to 1000 micrometers.

[0009] According to an embodiment of the present invention, the four corners of the joint portion are all chamfered structures.

[0010] According to an embodiment of the present invention, the chamfer is in an arc shape or a straight line shape.

[0011] According to an embodiment of the present invention, the second width of the joining portion along the second direction is greater than or equal to the first width of the joining portion along the first direction.

[0012] According to an embodiment of the present invention, the width of the chamfer along the second direction is less than or equal to the width of the chamfer along the first direction.

[0013] According to an embodiment of the present invention, the first width of the joint portion along the first direction is 1000-1400 microns, and / or the width of the chamfer along the first direction is 150-400 microns.

[0014] According to an embodiment of the utility model, the solar cell further comprises a plurality of first electrodes and a second electrode extending along the first direction, the plurality of first electrodes and the plurality of second electrodes are alternately arranged in sequence along the second direction, and a portion of the first electrodes are connected to the joint portion.

[0015] According to an embodiment of the present invention, at least a portion of the second electrode is discontinuous in the first direction, and the discontinuous position is formed as a first gap or a second gap.

[0016] According to an embodiment of the utility model, the solar cell further comprises a third electrode extending along the second direction, the third electrode is connected to the joint portion, the third electrode passes through the second gap, and the joint portion is located in the first gap.

[0017] The embodiment of the utility model further provides a battery string, comprising a plurality of solar cells and an interconnection bar, wherein the interconnection bar is connected to the connecting portions of two adjacent solar cells.

[0018] According to an embodiment of the present invention, the ratio of the width of the joint portion along the first direction to the width of the interconnection strip is configured to be 2-4.5.

[0019] An embodiment of the utility model further provides a photovoltaic assembly, comprising at least one battery string.

[0020] According to the solar cell, battery string and photovoltaic module provided by the utility model, the joint part is set to a rectangular shape with chamfers, which has a smaller area than the rectangular joint part without chamfers, and saves the material required for preparing the original chamfered part. The part defined by the first side reserves the effective welding area required for the interconnection strip, and the width of the chamfers on both sides of the first side set along the first direction is adapted to accommodate the spreading width of the solder along the first direction after welding and lamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of a solar cell according to an exemplary embodiment of the utility model, showing a joint portion;

[0022] Figure 2 is a schematic diagram of a solar cell according to an exemplary embodiment of the utility model, showing a non-linear main grid;

[0023] Figure 3 is a schematic diagram of a solar cell according to another exemplary embodiment of the utility model, showing a straight-line main grid;

[0024] Figure 4 yes Figure 1 A schematic diagram showing the position of the chamfer of the joint portion relative to the first side of the exemplary embodiment shown; and

[0025] Figure 5 yes Figure 1 The schematic diagram shows the principle of selecting the position of the chamfer of the joint portion relative to the first side and the second side of the exemplary embodiment shown.

[0026] In the drawings, the meanings of the reference numerals are as follows:

[0027] 1. Jointing part;

[0028] 2. Interconnection strip;

[0029] 3. Solder;

[0030] 4. a first electrode;

[0031] 5. A second electrode;

[0032] 6. The third electrode;

[0033] 61. Non-linear main grid;

[0034] 62. Linear main grid;

[0035] 7. A first connecting portion;

[0036] 8. a second connecting portion; and

[0037] 9. Node. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0039] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "include", "comprises", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0040] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0041] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0042] The joint (PAD point, i.e., pad) is the main connection point on the cell for welding the electrode and the interconnection strip (i.e., solder strip). The design of the joint must satisfy the requirement that the solder can wet and form an effective connection with the joint when welding the joint to the interconnection strip. To this end, the joint must have a sufficient effective welding area (i.e., the area of ​​the part of the joint used for welding to the interconnection strip), and on this basis, the area of ​​the other parts of the joint other than the part welded to the interconnection strip is reduced to reduce the amount of material (such as silver paste) used to manufacture the joint.

[0043] Therefore, how to provide a solar cell sheet with a smaller overall area and a joint portion that meets the effective welding area requirement has become a technical problem that needs to be solved urgently.

[0044] Figure 1It is a principle diagram of a solar cell according to an exemplary embodiment of the utility model, showing a joint portion.

[0045] According to the solar cell provided by the utility model, Figure 1 As shown, it includes a joint portion 1 disposed on at least one surface of the battery cell, and the joint portion 1 is used to connect with an external interconnection bar. The joint portion 1 is configured as a rectangular structure with a chamfer, wherein the joint portion 1 has a first side extending along a first direction and a second side extending along a second direction, and the first direction intersects the second direction. One end of the first side is connected to the second side through a chamfer, the interconnection bar extends along the second direction, and the ratio of the first width of the joint portion 1 along the first direction to the width of the chamfer in the first direction is between 2 and 6.

[0046] In an illustrative embodiment, Figure 1 As shown, the joint portion 1 has two first edges (such as Figure 1 ), and a second side (such as the upper side and the lower side shown in FIG. 1 ) disposed between the two first sides along the second direction. Figure 1 Further, the first direction (such as Figure 1 left and right directions as shown) and a second direction (as shown Figure 1 The up and down directions shown are perpendicular to each other.

[0047] In an illustrative embodiment, Figure 1 As shown, the adjacent first edge (such as Figure 1 The upper side shown) and the second side (as shown Figure 1 shown on the right) are connected by chamfering (as shown Figure 1 R shown, that is, at least one corner of the joint 1 forms a chamfered structure), wherein the first width of the first edge along the first direction (such as Figure 1 W2, i.e. the length of the first side) and the chamfer (such as Figure 1 The width of R) along the first direction (as shown Figure 1 The ratio of d) shown is configured to be any value between 2 and 6.

[0048] Based on the manufacturing process of the battery, the joint 1 (i.e., the pad) and the interconnection bar 2 (i.e., the solder strip) need to be welded together by a solder 3 (e.g., solder) disposed between the two. In response to welding, lamination, and other processes, the solder 3 will spread within a certain range, so that a portion of the solder 3 is exposed on both sides of the interconnection bar 2. In response to the tension of the liquid solder in the molten state and the external pressure along the thickness direction, the solder 3 often forms a spreading area in an approximately oblong shape (i.e., Figure 1 The shaded portion shown in FIG. 1 has a spreading width W3 along the first direction, so that a portion of the solder 3 is exposed outside the interconnection strip 2 along the first direction (ie, as shown in FIG. 1 ). Figure 1The width shown is the portion W4). Based on the shape characteristics of the spreading area, the solder 3 generally does not spread to the four corners (i.e., the upper left, lower left, upper right, and lower right) of the rectangular joint 1. Therefore, the shape of the joint 1 can be set accordingly, that is, the rectangular joint 1 is provided with at least one chamfer to save the material required for printing the chamfered portion of the joint 1.

[0049] According to the embodiments of the present utility model, Figure 1 As shown, the solar cell sheet further includes a third side extending along the second direction, and the other end of the first side is also connected to the third side through a chamfer.

[0050] According to the embodiments of the present utility model, Figure 1 As shown, the side length of the first side is configured to be greater than or equal to 500 micrometers and less than or equal to 1000 micrometers.

[0051] According to the embodiment of the utility model, Figure 1 As shown, the first width of the joint portion 1 along the first direction is 1000-1400 micrometers, and / or the width of the chamfer along the first direction is 150-400 micrometers.

[0052] In an illustrative embodiment, Figure 1 As shown, the joint portion 1 has two first edges (such as Figure 1 The upper and lower edges shown in FIG. 1 ), the second edge arranged along the second direction (such as Figure 1 right side as shown) and the third side (as shown Figure 1 1. The first side and the second side, as well as the first side and the third side are connected by chamfers. The first chamfer connecting the first side and the second side and the second chamfer connecting the second side and the third side can be configured to have the same shape and / or size. Similarly, the first chamfer and the second chamfer can also be configured to have different shapes and / or sizes to meet the welding requirements of the joint 1.

[0053] In an illustrative embodiment, Figure 1 As shown, the width of the welding portion 1 along the first direction (such as Figure 1 W5) is configured to be less than or equal to the welding portion 1 along the second direction (such as Figure 1 The width of the vertical direction (as shown) Figure 1 L1 shown), that is, W5≤L1.

[0054] In an illustrative embodiment, Figure 1 As shown, the joint portion 1 is arranged along a first direction (such as Figure 1 The width (ie, W5) in the left-right direction (as shown) includes, but is not limited to, being configured to be 1000 to 1400 microns (ie, 1000 μm≤W5≤1400 μm).

[0055] In a preferred embodiment, W5 is configured to be 1.3 mm (ie, W5 = 1.3 mm). Accordingly, L1 is configured to be ≥ 1.3 mm (ie, L1 ≥ 1.3 mm). In the case of L1 = 1.3 mm, the welded portion forms a square. Further, the side length of the first side (eg, Figure 1 The W2 shown includes but is not limited to being configured to be 500 to 1000 microns (ie, 500 μm≤W2≤1000 μm). It should be understood that the embodiments of the present invention are not limited thereto.

[0056] For example, W5 can be configured to be 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or any other size suitable for being arranged on the surface of a solar cell and welded to an interconnection strip.

[0057] For another example, W2 can be configured to be 400 microns, 450 microns, 1050 microns, 1100 microns, or any size smaller than W5.

[0058] According to the embodiments of the present utility model, Figure 1 As shown, the four corners of the joint 1 are chamfered.

[0059] According to the embodiments of the present utility model, Figure 1 As shown, the chamfer is configured in an arc shape or a straight line shape.

[0060] In an illustrative embodiment, Figure 1 As shown, the joint portion 1 has a first direction (such as Figure 1 The left and right directions shown in FIG. 1 are parallel to each other and spaced apart from each other, and the ... spaced apart from each other, and the left and right directions shown in Figure 1 Furthermore, the adjacent first edges and second edges are connected by chamfers to form a joint portion 1 with four chamfers.

[0061] In an illustrative embodiment, Figure 1 As shown, the four chamfers of the joint portion 1 are all configured in an arc shape.

[0062] In another exemplary embodiment, not shown in the figure, the four chamfers of the joint portion 1 are configured as straight lines.

[0063] In yet another exemplary embodiment, not shown in the drawings, a portion of the four chamfers of the joint portion 1 is configured in an arc shape, and another portion is configured in a straight line shape.

[0064] Among them, the arc-shaped chamfer includes but is not limited to any one of a right arc-shaped chamfer, an elliptical arc-shaped chamfer and a quasi-arc-shaped chamfer; the straight-line-shaped chamfer includes but is not limited to a line segment connecting the first edge and the second edge or a polyline connecting the first edge and the second edge.

[0065] According to the embodiment of the utility model, Figure 1 As shown, the second width of the joining portion 1 along the second direction is greater than or equal to the first width of the joining portion 1 along the first direction.

[0066] According to the embodiments of the present utility model, Figure 1 As shown, the width of the chamfer along the second direction is less than or equal to the width of the chamfer along the first direction.

[0067] In an illustrative embodiment, Figure 1 As shown, the length of the first side (such as Figure 1 W2) is configured to be greater than or equal to the width of the chamfer along the first direction (ie, as shown in FIG. Figure 1 d shown), and is less than or equal to four and a half times the width of the chamfer along the first direction (i.e., d≤W2≤4.5d). Preferably, the length of the first side includes, but is not limited to, being configured to be 4 times the width of the chamfer along the first direction (i.e., W2=4d). Further, the width of the chamfer along the first direction includes, but is not limited to, being configured to be greater than or equal to 150 microns and less than or equal to 400 microns (i.e., 150μm≤d≤400μm).

[0068] In an illustrative embodiment, Figure 1 As shown, the two ends of the first side (such as Figure 1 The left end and the right end shown in the figure are connected to the adjacent second side by chamfers. In detail, the chamfers include but are not limited to being set in a circular arc shape or an elliptical arc shape (ie, d≥L2).

[0069] In such an embodiment, the rectangular area defined between the two first sides is used as the main area for soldering with the interconnection strip, and the trapezoidal (or quasi-trapezoidal) area formed between the chamfers on both sides of the first side is used as an area for accommodating the solder 3 spreading along the first direction. In this way, the joint 1 with four chamfers has a smaller overall area than the joint 1 with a rectangular structure without chamfers, and since the chamfered part is omitted, the material required for manufacturing the joint 1 can be reduced.

[0070] Figure 2 It is a schematic diagram of a solar cell according to an exemplary embodiment of the utility model, showing a non-linear main grid. Figure 3 It is a schematic diagram of a solar cell according to another exemplary embodiment of the utility model, showing a straight-line main grid.

[0071] According to the embodiments of the present utility model, Figure 2 and Figure 3 As shown, the solar cell further includes a plurality of first electrodes 4 and a second electrode 5 extending along a first direction. The plurality of first electrodes 4 and the plurality of second electrodes 5 are arranged along the first direction (eg Figure 2 and Figure 3 The second direction (such as the left and right directions shown) intersects Figure 2 and Figure 3 The first electrodes 4 are arranged alternately in sequence in the up and down direction as shown, and a part of the first electrodes 4 is connected to the bonding part 1.

[0072] In an illustrative embodiment, Figure 2 and Figure 3 As shown, the solar cell further includes a first electrode 4 having the same polarity as the joint portion 1 and a second electrode 5 having a different polarity from the joint portion 1. In detail, the first electrode 4 and the second electrode 5 are connected along the second direction (eg Figure 2 and Figure 3 The doped regions are arranged alternately in the up and down direction as shown in the figure, to correspond to the different doping regions arranged on the back side of the solar cell (ie, to form a back contact cell).

[0073] For example, a cell with n-type silicon as the main body has p+ doped regions and n+ doped regions arranged in parallel and spaced apart on the back side. The first electrode 4 is arranged on the p+ doped region and is configured as the positive electrode; the second electrode 5 is arranged on the n+ doped region and is configured as the negative electrode. Similarly, the first electrode 4 can be configured as the negative electrode, and the second electrode 5 can be configured as the positive electrode.

[0074] According to the embodiments of the present utility model, Figure 2 and Figure 3 As shown, at least a portion of the second electrode 5 is discontinuous in the first direction and the discontinuous position is formed as a first gap or a second gap.

[0075] According to the embodiments of the present utility model, Figure 2 and Figure 3 As shown, the solar cell further includes a third electrode 6 extending along the second direction, the third electrode 6 is connected to the joint portion 1, the third electrode 6 passes through the second gap, and the joint portion 1 is located in the first gap.

[0076] In an illustrative embodiment, Figure 2 and Figure 3 As shown, the second electrode 5 includes a plurality of electrode segments spaced apart along a first direction. Specifically, a first gap and a second gap are formed between adjacent electrode segments.

[0077] In an illustrative embodiment, Figure 2 and Figure 3As shown, the first electrode 4, the second electrode 5 and the third electrode 6 are all arranged on the back of the cell. In detail, the first electrode 4 and the second electrode 5 are configured with different polarities and serve as the secondary grid of the cell; the third electrode 6 passes through the second gap formed by the second electrode 5 of different polarity and is connected to the first electrode 4 of the same polarity.

[0078] In such an embodiment, the first electrode 4 (i.e., the auxiliary grid having the same polarity as the joint 1) and the second electrode 5 (i.e., the auxiliary grid having a different polarity from the joint 1) are suitable for collecting the current generated in the battery cell, and the third electrode 6 (i.e., the main grid) is suitable for collecting the current collected by the plurality of first electrodes 4. It should be understood that the embodiments of the present utility model are not limited thereto.

[0079] For example, the first electrode 4 is directly connected to the interconnection bar 2 (i.e., the welding strip), so that the current collected by the first electrode 3 is directly collected through the interconnection bar 2 (i.e., the welding strip). That is, a solar cell without a main grid structure. In this way, the material required for printing the main grid can be omitted and the corresponding printing process can be simplified.

[0080] In an illustrative embodiment, Figure 2 and Figure 3 As shown, the electrode segments of the second electrode 5 located on both sides of the joint 1 form a first gap. Figure 2 and Figure 3 The battery segment that is offset from the joint 1 (in the up-down direction shown) forms a second gap.

[0081] In an illustrative embodiment, Figure 2 and Figure 3 As shown, the width of the first gap (i.e., S1) is configured to be greater than the width of the second gap (i.e., S2, i.e., S1>S2). Further, the joint 1 includes but is not limited to spanning two second electrodes 5 along the second direction. Furthermore, the first electrode 4 located between the two second electrodes 5 passes through the joint 1 along the second direction (i.e., Figure 2 The midline of the image (in the up and down direction shown).

[0082] Based on the current manufacturing process, the secondary grid (i.e., the first electrode 4 and the second electrode 5) is often configured to be thinner and thinner, and arranged more and more densely along the second direction. On this basis, based on the design of the above embodiment, at least one first electrode 4 can be connected to the joint 1 (i.e., the pad), which is conducive to maintaining a large tensile resistance between the joint 1 and the first electrode 4. It should be understood that the embodiments of the utility model are not limited to this.

[0083] For example, the joint 1, the first electrode 4 and the third electrode 6 can be respectively arranged on two opposite surfaces (i.e., the front and back sides) of the cell, and the structure of the second electrode 5 is omitted, that is, a heterojunction cell is formed. Based on similar technical concepts, the joint 1 arranged on the heterojunction cell structure can still meet the design requirements of effectively connecting with the interconnection bar 2 and saving materials for manufacturing the joint 1.

[0084] In an illustrative embodiment, Figure 2 and Figure 3 As shown, the solar cell further includes a first connecting portion 7 extending along the first direction, and the first connecting portion 7 connects the joint portion 1 and a portion of the first electrode 4. In detail, the two ends (such as Figure 2 and Figure 3 The left and right ends of the first connecting portion 7 are symmetrically provided. Further, the end of the first connecting portion 7 away from the joint portion 1 (as shown in Figure 2 The width of the left end of the first connecting portion 7 located on the left side of the joint 1 is configured to be smaller than the end portion near the joint 1 (such as Figure 2 The width of the first connecting portion 7 (shown as the right end of the first connecting portion 7 located on the left side of the joint 1) is shown.

[0085] For example, the first connection portion 7 is configured as a trapezoidal structure.

[0086] Or, for example, the first connecting portion 7 is configured as a triangular structure.

[0087] In an illustrative embodiment, Figure 2 and Figure 3 As shown, the first connection portion 7 is configured to be connected along a first direction (such as Figure 2 and Figure 3 In detail, the length of the first connecting portion 7 (i.e., Figure 2 and 3 The distance between the left end and the right end of the first connecting portion shown in the figure) includes but is not limited to being configured to be less than half of the width (i.e., W5) of the joint portion 1 along the first direction, such as 0.3 mm to 0.8 mm. The width of the narrowest position of the first connecting portion 7 is configured to be greater than the width of the first electrode 4, and the width of the widest position of the first connecting portion 7 includes but is not limited to being configured to be 0.05 mm to 0.2 mm.

[0088] In such an embodiment, the first connection portion 7 increases the width of the connection position between the first electrode 4 and the joint portion 1, which helps prevent the molten solder 3 from fusing with the first electrode 4, thereby preventing the first electrode 4 from being blown, and also helps prevent current concentration.

[0089] In an illustrative embodiment, Figure 2 and Figure 3 As shown, the solar cell further includes a second connection portion 8 extending along the second direction, and the second connection portion 8 connects the third electrode 6 and the joint portion 1. In detail, the second connection portion 8 is configured to extend along the second direction (such as Figure 2 and Figure 3 Further, the length of the second connecting portion 8 includes but is not limited to being configured to be less than the length of the bonding portion 1. Furthermore, the second connecting portion 8 is provided with a node 9 connected to the first electrode 4.

[0090] Similar to the first connecting portion 7, the end of the second connecting portion 8 away from the joint portion 1 (eg Figure 2 The width of the second connecting portion 8 (the upper end of the second connecting portion 8 located on the upper side of the connecting portion 1) is configured to be smaller than the width of the end portion near the connecting portion 1 (such as Figure 2 The width of the lower end of the first connecting portion 7 located on the upper side of the joint 1 as shown.

[0091] In such an embodiment, the first connection portion 7 and / or the second connection portion 8 is configured as a structure with a width gradually decreasing from the distal end to the proximal end, which is beneficial to further prevent current concentration and can more effectively improve the current collection effect.

[0092] In an illustrative embodiment, Figure 2 As shown, the third electrode 6 includes but is not limited to a non-linear main grid 61 with an irregular shape. In detail, the non-linear main grid 61 includes but is not limited to a folded line structure, and the connection portion with the first electrode 4 forms a node 9 protruding toward the first electrode 4. Further, the node 9 includes but is not limited to a diamond structure to increase the width of the connection position between the auxiliary grid and the main grid.

[0093] In such an embodiment, the printing method of the first electrode 4, the second electrode 5 and the third electrode 6 is configured based on the screen plate used (such as a screen plate with mesh knots and a screen plate without mesh knots). For example, the non-linear main grid 61 can be printed by a screen plate without mesh knots, so that the non-linear main grid 61 can be printed integrally with at least a portion of the first electrode 4 to simplify the printing process. It should be understood that the embodiments of the utility model are not limited to this.

[0094] For example, see Figure 3 As shown, the third electrode 6 is configured as a straight-line main grid 62 .

[0095] Based on the same inventive concept, the utility model also provides a battery string, such as Figure 1 As shown, it includes a plurality of solar cells and interconnection bars 2. The interconnection bars 2 are connected to the connecting parts 1 of two adjacent solar cells.

[0096] In an illustrative embodiment, Figure 1As shown, the interconnection strip 2 (ie, welding strip) is suitable for connecting the positive electrode of one solar cell in series with the negative electrode of another solar cell, so that multiple solar cells in the battery string are connected in series.

[0097] According to the embodiments of the present utility model, Figure 1 As shown, the ratio of the width of the joint portion 1 along the first direction to the width of the interconnection bar 2 is configured to be 2-4.5.

[0098] In an illustrative embodiment, Figure 1 As shown, the width of the interconnection strip 2 (ie, the solder strip) (eg Figure 1 The width of the joint portion 1 along the first direction (eg, W1) is configured to be, but not limited to, 300 μm to 600 μm (ie, 300 μm ≤ W1 ≤ 600 μm). Figure 1 W5 shown) and the width of the interconnection strip 2 (as shown Figure 1 The ratio of W1) shown (ie, W5 / W1) includes but is not limited to being configured as 2 to 4.5.

[0099] In a preferred embodiment, the width of the interconnection strip 2 (ie, the soldering strip) includes but is not limited to being configured as 500 micrometers or 600 micrometers (ie, W1 =500 μm, or W1 =600 μm).

[0100] In the design of the joint 1, in addition to considering the shape and size (including but not limited to the first width, i.e., W1) of the interconnection bar 2 (i.e., soldering strip), it is also necessary to consider the offset of the interconnection bar 2 (i.e., soldering strip) and / or solder 3 relative to the joint 1 (i.e., soldering pad) caused by the accuracy of the equipment (such as welding machine and machine) in actual manufacturing. A certain amount of space needs to be reserved for the offset value generated by the offset to prevent the reduction of the solderability of the interconnection bar 2 (i.e., soldering strip) and the solar cell due to the offset of the solder 3 and / or the interconnection bar 2 relative to the joint 1.

[0101] Figure 4 yes Figure 1 The schematic diagram shows the position of the chamfer of the joint portion relative to the first side of the exemplary embodiment shown.

[0102] Reference Figure 4 As shown, when the interconnection strip 2 (i.e., the welding strip) is welded to the joint 1, the preferred arrangement is that the interconnection strip 2 (i.e., the welding strip) penetrates the joint 1 along the middle of the joint 1. That is, in the thickness direction facing the joint 1 (i.e., as shown in FIG. Figure 4 In the orthographic projection of the direction facing the paper surface shown in FIG. 1 , the interconnection strip 2 (ie, the welding strip) with a substantially rectangular structure is formed along a first direction (eg, Figure 4 The midline of the joint (in the left-right direction shown) coincides with the projection of the midline of the joint 1.

[0103] However, in the actual manufacturing process, due to the accuracy of the equipment (such as a welding machine), it is inevitable that positional offset will occur when welding the interconnection strip 2 (i.e., the welding strip) to the joint 1. The offset is mainly reflected in the following aspects: Figure 4 In the left and right directions shown, that is, the center line of the interconnection strip 2 (i.e., the welding strip) is offset (e.g., toward Figure 4 The left or right side shown in the figure is offset from the center line of the joint 1. Therefore, the first side of the joint 1 (i.e., Figure 4 The side length of the first side (AD) is designed to prevent the interconnection strip 2 (ie, the soldering strip) from being misaligned with the first side due to the first side being too short.

[0104] On this basis, in an illustrative embodiment, as Figure 4 As shown, the length of the first side (i.e. AD) (i.e. L <ad>, that is Figure 1 The width W2 shown in the figure should be at least larger than the width of the interconnection strip 2 (ie, the solder strip) (ie, L <bc>, that is Figure 1 Furthermore, since the displacement of the interconnection strip 2 (i.e., the soldering strip) relative to the joint portion 1 (i.e., the soldering pad) is mainly limited by the accuracy of the welding equipment (e.g., the welding machine), the width (i.e., L) of the reserved portion of the first side located on both sides (i.e., AB and CD) of the interconnection strip 2 (i.e., the soldering strip) is <ab>and L <cd>) can be set in response to the precision of the device.

[0105] For example, L <ab>and / or L <cd>Including but not limited to being configured as any value between 0.05 mm and 0.5 mm.

[0106] To this end, the length of the first side (L <ad>, that is Figure 1 The width W2 shown can be configured as the sum of the width of the interconnection strip 2 (ie, the welding ribbon) and twice the welding machine accuracy.

[0107] In such an embodiment, the length of the first side is set to be greater than the width of the interconnection strip 2 (i.e., the welding strip), so that the joint portion 1 can meet the welding requirements of the interconnection strip 2 (i.e., the welding strip). In addition, by designing the length of the first side, the maximum value requirement of the interconnection strip 2 (i.e., the welding strip) offset to both sides of the center line of the joint portion 1 within the accuracy range of the welding machine can be met, so as to prevent the interconnection strip 2 (i.e., the welding strip) from being misaligned with the joint portion 1 and causing desoldering.

[0108] Reference Figure 4 As shown, the chamfered area of ​​the joint 1 configured as a rectangular structure with chamfers is not only related to the length of the first side (AD, i.e., the selection of point A and point D), but can also be further designed by configuring the length of the second side (EG, i.e., the selection of point E and point G).

[0109] For example, based on the positions of point A and point D being determined, the length of the second side (i.e., L <eg>) is smaller, the chamfer area is larger, that is, the less material is needed to manufacture the joint 1. However, the length of the second side is also limited by other factors. For example, it is limited by the offset of the solder 3 relative to the joint 1.

[0110] Figure 5 yes Figure 1 The schematic diagram shows the principle of selecting the position of the chamfer of the joint portion relative to the first side and the second side of the exemplary embodiment shown.

[0111] In an illustrative embodiment, Figure 5 As shown, the solder 3 is preferably arranged in the middle of the joint 1 (such as Figure 5 The solid line shown in FIG. 1 forms an approximate circle), and the center of the solder 3 ( Figure 5 The Y point shown) and the center of the joint 1 ( Figure 5 That is, in the case of Figure 5 The orthographic projection in the thickness direction facing the joint portion 1 (i.e. Figure 5 In the direction facing the paper surface), there is a circular solder 3 with point V as the center and Lw as the diameter.

[0112] However, in the actual manufacturing process, due to the limitation of the accuracy of the equipment (such as the machine), it is inevitable that position deviation will occur when the solder 3 is printed (i.e. Figure 5 The circle formed by the dotted line shown in the figure) is formed, that is, the center of the solder 3 (i.e., point Y) is offset from the center of the joint 1 (i.e., point V). Figure 5 As shown, the circular solder 3 with point Y as the center and point Lw as the diameter is offset to the upper right from the center of the joint 1 (ie, point V).

[0113] On this basis, based on the shape difference between the circular solder 3 and the joint 1, the roughly triangular area formed by the portion outside the end point (such as the angle formed by point D, point E and the upper right end point of the joint 1) will basically not overlap with the solder 3, and therefore, it can be regarded as a portion of the joint 1 that does not need to be retained. Figure 5 The first offset value along the first direction (as shown in the up and down direction) and the first offset value along the first direction (as shown in the up and down direction) Figure 5 The second offset value of the left and right direction (as shown) can be used as the connection point between the chamfer (ie, DE) and the first side (ie, AD), and the point E can be used as the connection point between the chamfer (ie, DE) and the second side (ie, EG).

[0114] In an illustrative embodiment, Figure 5 As shown, based on the current process requirements, the accuracy of the configured machine along the first direction and the second direction is mainly any value between 0.05 mm and 0.2 mm. For this reason, the first offset value (i.e., VX) and the second offset value (i.e., VW) can be configured to be the same as the accuracy value of the configured machine. The first offset value and the second offset value may be different (e.g., the first offset value is 0.1 mm, and the second offset value is 0.15 mm).

[0115] Referring to the above embodiment, it can be seen that the connection point between the chamfer and the second side (such as Figure 4 The connection point between DE and EG (point E) shown is limited by both the offset of the interconnection strip 2 (ie, solder strip) relative to the joint 1 and the offset of the solder 3 relative to the joint 1 .

[0116] To this end, the point (ie, point E) must be greater than or equal to half the length of the portion of the first side that overlaps with the solder 3 (ie, DD') plus the length of the center of the solder 3 along the first direction (ie, Figure 5 The sum of the second offset values ​​(i.e., L <vw>+L<DD’> / 2, refer to Figure 5 The third offset value of the interconnection strip 2 (ie, the solder strip) offset from the center of the first side along the first direction plus half of the width of the interconnection strip 2 (ie, the solder strip) (ie, L <bc> / 2+L <ab>, refer to Figure 4 In this way, the chamfer formed with this point (ie, point E) as the endpoint can simultaneously meet the offset requirements of the interconnection strip 2 (ie, solder strip) and the solder 3.

[0117] Based on the same inventive concept, the photovoltaic assembly provided by the utility model, not shown in the figure, includes at least one battery string.

[0118] In another exemplary embodiment, a photovoltaic module includes a plurality of battery strings arranged side by side.

[0119] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only for reference to the drawings and are not intended to limit the scope of protection of the present invention. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted when they may cause confusion in the understanding of the present invention.

[0120] The embodiments of the present invention are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present invention is defined by the attached claims and their equivalents. Without departing from the scope of the present invention, a person skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present invention.< / ab> < / bc> < / vw> < / eg> < / ad> < / cd> < / ab> < / cd> < / ab> < / bc> < / ad>

Claims

1. A solar cell, comprising a junction (1) arranged on at least one surface of the cell, wherein the junction (1) is used to connect to an external interconnection strip, It is characterized in that The joint portion (1) is configured as a rectangular structure with chamfered corners; The joint portion (1) has a first side extending along a first direction and a second side extending along a second direction, the first direction intersects with the second direction; one end of the first side is connected to the second side via a chamfer, the interconnection strip extends along the second direction, and the ratio of a first width of the joint portion (1) along the first direction to a width of the chamfer along the first direction is between 2 and 6.

2. The solar cell according to claim 1, It is characterized in that It also includes a third side extending along the second direction, and the other end of the first side is also connected to the third side through a chamfer.

3. The solar cell according to claim 2, It is characterized in that The side length of the first side is configured to be greater than or equal to 500 micrometers and less than or equal to 1000 micrometers.

4. The solar cell according to claim 1, It is characterized in that The four corners of the joint portion (1) are all chamfered structures.

5. The solar cell according to claim 1, It is characterized in that The chamfer is in an arc shape or a straight line shape.

6. The solar cell according to claim 1, It is characterized in that The second width of the joining portion (1) along the second direction is greater than or equal to the first width of the joining portion (1) along the first direction.

7. The solar cell according to claim 1, It is characterized in that A width of the chamfer along the second direction is less than or equal to a width of the chamfer along the first direction.

8. The solar cell according to any one of claims 1 to 7, It is characterized in that The first width of the joint portion (1) along the first direction is 1000-1400 micrometers, and / or the width of the chamfer along the first direction is 150-400 micrometers.

9. The solar cell according to claim 1, It is characterized in that It also comprises a plurality of first electrodes (4) and a plurality of second electrodes (5) extending along the first direction, wherein the plurality of first electrodes (4) and the plurality of second electrodes (5) are alternately arranged in sequence along the second direction, and a portion of the first electrodes (4) is connected to the joint portion (1).

10. The solar cell according to claim 9, It is characterized in that At least a portion of the second electrode (5) is discontinuous in the first direction, and the discontinuous position is formed as a first gap or a second gap.

11. The solar cell according to claim 10, It is characterized in that It also comprises a third electrode (6) extending along the second direction, the third electrode (6) being connected to the joint portion (1), the third electrode (6) passing through the second gap, and the joint portion (1) being located in the first gap.

12. A battery string, It is characterized in that include: A plurality of solar cells as claimed in any one of claims 1 to 11; as well as An interconnection strip (2) is joined to the joining portions (1) of two adjacent solar cell sheets.

13. The battery string according to claim 12, It is characterized in that The ratio of the width of the joint portion (1) along the first direction to the width of the interconnection strip (2) is configured to be 2 to 4.

5.

14. A photovoltaic module, It is characterized in that Comprising at least one battery string as claimed in claim 12 or 13.

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