Electrode structure of back contact cell, cell piece and solar cell module

Abstract

The utility model is suitable for the field of photovoltaic technology, and provides an electrode structure of a back contact cell, a cell piece and a solar cell module, and the electrode structure comprises a main grid which is closest to a first edge of the back contact cell; the first connection grid line is connected with the main grid, the pad point and the main grid are arranged at intervals in the first direction, the first end of the second connection grid line is in electric contact with the pad point, the second end of the second connection grid line extends in the second direction, and the first direction intersects with the second direction. When the welding strip is arranged on the battery piece and connected with the pad point, the welding strip extends to the second connecting grid line, so that burrs on the edge of the welding strip are blocked by the second connecting grid line, the burrs on the edge of the welding strip are prevented from directly puncturing the insulating paste to be communicated with the opposite grid line, and the second connecting grid line plays a role in protecting the battery piece. The risk of local short circuit of the battery piece is avoided, and the yield of the battery piece can be effectively improved.

Description

Technical Field

[0001] The present application belongs to the field of photovoltaic technology, and in particular relates to an electrode structure of a back-contact cell, a cell sheet, and a solar cell module. Background Art

[0002] Back-contact solar cells are cells in which both the emitter and base contact electrodes are placed on the back of the cell. The light-receiving surface of the cell is not blocked by any metal electrodes, which effectively increases the short-circuit current of the cell. In addition, this type of cell with no obstruction on the front not only has a high conversion efficiency, but also looks more beautiful. At the same time, components with full back electrodes are easier to assemble.

[0003] In the electrode pattern design of existing back-contact solar cells, the main grid lines and pad points in the edge area of ​​the cell are separated, and the welding ribbon is connected to the pad point away from the edge of the cell, avoiding the stress concentration caused by setting the welding ribbon at the edge of the cell, which may cause hidden cracks in the cell. In such an electrode pattern, since there are burrs on the edge of the welding ribbon after cutting, when the welding ribbon is set on the cell, the burrs on the edge of the welding ribbon can easily pierce the insulating glue, causing the welding ribbon to connect with the opposite grid line, and there is a risk of local short circuit in the cell. Utility Model Content

[0004] The present application provides a solar cell, which aims to solve the problem that due to burrs on the edge of the soldering ribbon after cutting, when the soldering ribbon is set on the solar cell, the burrs on the edge of the soldering ribbon can easily pierce the insulating glue, causing the soldering ribbon to connect with the opposite-sex grid line, and there is a risk of local short circuit in the solar cell.

[0005] The present application is implemented as follows: an electrode structure of a back-contact battery, comprising:

[0006] a busbar closest to the first edge of the back contact cell;

[0007] A pad point, wherein the pad point and the main gate are spaced apart in a first direction, and a distance between the pad point and the first edge is greater than a distance between the main gate and the first edge;

[0008] a first connecting gate line, wherein a first end of the first connecting gate line is in electrical contact with the pad point, and a second end of the first connecting gate line is in electrical contact with the main gate;

[0009] A second connecting gate line, wherein a first end of the second connecting gate line is in electrical contact with the pad point, and a second end of the second connecting gate line extends along a second direction, and the first direction and the second direction intersect.

[0010] Optionally, the second end of the second connecting wire extends along the second direction to a second edge of the back contact cell.

[0011] Optionally, the second end of the second connecting wire extends along the second direction and is spaced apart from the second edge of the back contact battery.

[0012] Optionally, a distance from the second end of the second connecting wire to the second edge is 1 mm to 20 mm.

[0013] Optionally, the second connecting gate line includes an extension segment and an end segment, the extension segment and the end segment are connected, and a width of the end segment is greater than a width of the extension segment.

[0014] Optionally, it further includes a first curved gate line arranged between the main gate and the pad point, and a second curved gate line arranged between the main gate and the second connecting gate line. In the second direction, the first curved gate line and the second curved gate line are located on both sides of the first connecting gate line.

[0015] Optionally, the first curved gate line is bent toward the main gate and the pad point respectively and does not contact the main gate and the pad point, or the first curved gate line is bent toward the main gate and does not contact the main gate, or the first curved gate line is bent toward the pad point and does not contact the pad point.

[0016] Optionally, the second curved gate line is bent toward the main gate and the second connecting gate line respectively and does not contact the main gate and the second connecting gate line, or the second curved gate line is bent toward the main gate and does not contact the main gate, or the second curved gate line is bent toward the second connecting gate line and does not contact the second connecting gate line.

[0017] The present application sets a pad point and a second connecting grid line connected to the pad point. When the welding ribbon is set on the battery cell and connected to the pad point, the welding ribbon extends to the second connecting grid line. In this way, the burrs on the edge of the welding ribbon are blocked by the second connecting grid line, thereby preventing the burrs on the edge of the welding ribbon from directly piercing the insulating glue and connecting with the opposite-sex grid line. The second connecting grid line protects the battery cell, avoids the risk of local short circuit in the battery cell, and can effectively improve the yield of the battery cell.

[0018] A battery cell includes the aforementioned electrode structure of a back-contact battery. The technical effects of this application are the same as those of the aforementioned electrode structure of a back-contact battery, and will not be described in detail here.

[0019] Optionally, the battery cell includes at least four electrode structures respectively arranged at four corners of the battery cell.

[0020] A solar cell module comprises the above-mentioned cell and a welding ribbon, wherein the welding ribbon is connected to the pad point and extends along the second direction, and the orthographic projection of the welding ribbon on the cell and the orthographic projection of the second connecting grid line on the cell at least partially overlap.

[0021] Optionally, the welding ribbon has a free end extending along the second direction toward the second edge, and the distance from the free end to the second edge of the back contact battery is greater than the distance from the second end of the second connecting wire to the second edge of the back contact battery.

[0022] Optionally, the second connecting gate line includes an extension section and an end section, the extension section and the end section are connected, the width of the end section is greater than the width of the extension section, and the free end extends to the end section, and the width of the end section is greater than the width of the free end.

[0023] Optionally, the width of the second connecting grid line is greater than the width of the welding strip.

[0024] The welding strip and the second connecting grid line of the present application are arranged in the same direction, and the orthographic projection of the welding strip on the battery cell and the orthographic projection of the second connecting grid line on the battery cell at least partially overlap. In this way, in the arrangement path of the welding strip, the second connecting grid line isolates the welding strip from direct contact with the fine grid lines of the battery cell, thereby avoiding the risk of short circuit caused by contact between the welding strip and the fine grid lines on the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of the electrode structure of the first back-contact battery provided in the present application;

[0026] Figure 2 This is a schematic structural diagram of the first solar cell assembly provided in the present application;

[0027] Figure 3 This is a schematic structural diagram of the electrode structure of the second back contact battery provided in the present application;

[0028] Figure 4 This is a schematic structural diagram of the second solar cell assembly provided in the present application.

[0029] Description of reference numerals:

[0030] 100, main grid; 200, pad point; 300, first connecting grid line; 400, second connecting grid line; 401, extension section; 402, end section; 500, first curved grid line; 600, second curved grid line; 700, battery cell; 701, first edge; 702, second edge; 800, welding strip; 801, free end. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are merely used to explain the present application and are not intended to limit the present application.

[0032] In the description of this application, it should be understood that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on this application.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the described features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0034] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0035] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0036] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0037] like Figures 1-4 As shown, an electrode structure of a back-contact battery includes a main grid 100 , a pad 200 , a first connecting grid line 300 , a second connecting grid line 400 , a first curved grid line 500 and a second curved grid line 600 .

[0038] In this embodiment, the main grid 100 is the main grid 100 closest to the first edge 701 of the back contact battery, that is, the main grid 100 closest to the first edge 701 of the back contact battery can be defined as an edge main grid. It can be understood that the electrode structure should also include other main grids, that is, it can be defined as a center main grid. In the arrangement structure of the main grid 100 in the battery cell 700, the edge main grid and the center main grid are parallel to each other. Correspondingly, the pad point 200 connected to the edge main grid can also be defined as an edge pad point, and the pad point 200 connected to the center main grid is defined as a center pad point. As mentioned above, in order to avoid the stress concentration caused by the setting of the welding ribbon 800 at the edge of the battery cell 700, which causes the battery cell 700 to crack, the present application separates the edge main grid and the edge pad point of the battery cell 700, so that the welding ribbon 800 is connected to the edge pad point and is away from the edge of the battery cell 700. In such an electrode pattern, the edge main grid is no longer stacked with the welding strip 800, and the welding strip 800 is in direct contact with the fine grid line area. Due to the limitations of the existing cutting process, burrs will inevitably exist on the edge of the welding strip 800 after cutting, which brings safety hazards to the direct electrical conduction between the welding strip 800 and the fine grid line area.

[0039] Therefore, in the embodiment of the present application, a second connecting grid line 400 is provided on the cell 700 to connect to the pad point. The second connecting grid line 400 is provided parallel to the main grid 100 and is also aligned with the extending direction of the welding ribbon 800. In this way, when the welding ribbon 800 is welded to the cell 700, the welding ribbon 800 is isolated from the fine grid line area by the second connecting grid line 400. Even if there are burrs on the edge of the welding ribbon 800, the welding ribbon 800 is isolated by the second connecting grid line 400 and cannot form electrical conduction with the fine grid line.

[0040] The second connecting grid lines 400 can be formed by screen printing a metal paste onto the surface of the cell 700 to form the second connecting grid lines 400. The metal paste can be silver paste, aluminum paste, or the like. The specific material of the metal paste is not limited; in actual use, technicians can select an appropriate material based on their needs. Similarly, the edge busbar 100 and the first connecting grid lines 300 can also be prepared using the above method, and will not be further described here.

[0041] In some embodiments, specifically, in order to effectively collect carriers at the edge of the cell 700, a main grid 100 must be set at the edge of the cell 700 to converge the carriers collected by the fine grid lines at the edge and then lead them out through the solder ribbon 800 connected to the pad. Since the conventional edge main grid 100 and the edge pad point 200 are arranged in the same line, when the solder ribbon 800 is arranged on the edge pad point 200, it is very easy to cause hidden cracks in the cell 700. To improve this disadvantage, the pad point 200 and the main grid 100 are spaced apart in the first direction, and the distance between the pad point 200 and the first edge 701 is greater than the distance between the main grid 100 and the first edge 701. For example, referring to Figure 1 The distance between the leftmost side of the pad point 200 and the first edge 701 is greater than the distance between the leftmost side of the main grid 100 and the first edge 701. A first connecting grid line 300 is provided between the pad point 200 and the main grid 100 for carrier convergence. The first end of the first connecting grid line 300 is in electrical contact with the pad point 200, and the second end of the first connecting grid line 300 is in electrical contact with the main grid 100. This electrode pattern design effectively solves the hidden danger of cracking the cell 700 caused by the solder ribbon 800 being arranged at the edge of the cell 700.

[0042] At the same time, a second connecting grid line 400 is also provided in the electrode structure, and the first end of the second connecting grid line 400 is electrically contacted with the pad point 200, and the second end of the second connecting grid line 400 extends along the second direction, and the first direction and the second direction intersect. In the present application, the second connecting grid line 400 and the pad point 200 are connected to play a role in the transmission of carriers. At the same time, it can be understood that the second connecting grid line 400 is connected to the fine grid line of the same polarity, and the second connecting grid line 400 can converge the fine grid line area passed by. In an embodiment of the present application, the second direction intersects with the first direction. Specifically, the second direction can be perpendicular to the first direction. For example, the first direction can be the width direction of the battery cell 700, and the second direction can be the length direction of the battery cell 700. In the present application, the first edge 701 is the edge of the battery cell 700 set relatively in the first direction, and the second edge 702 is the edge of the battery cell 700 set relatively in the second direction.

[0043] In the present application, a pad point 200 and a second connecting grid line 400 connected to the pad point 200 are set. When the welding ribbon 800 is set on the battery cell 700 and connected to the pad point 200, the welding ribbon 800 extends to the second connecting grid line 400. In this way, the burrs on the edge of the welding ribbon 800 are blocked by the second connecting grid line 400, thereby preventing the burrs on the edge of the welding ribbon 800 from directly piercing the insulating glue and connecting with the opposite grid line. The second connecting grid line 400 protects the battery cell 700, avoids the risk of local short circuit in the battery cell 700, and can effectively improve the yield of the battery cell 700.

[0044] In some embodiments, the second end of the second connecting grid line 400 extends along the second direction to the second edge 702 of the back-contact cell. This allows the second connecting grid line 400 to converge carriers from the fine grid lines over a larger area. Furthermore, the soldering ribbon 800 can extend along the second connecting grid line 400 to the second edge 702 of the back-contact cell. This design reduces the current transmission path within the cell 700, reduces resistance loss, and thus improves current transmission efficiency.

[0045] In other embodiments, the second end of the second connecting grid line 400 extends along the second direction and is spaced apart from the second edge 702 of the back contact battery. The welding ribbon 800 is stacked on the second connecting grid line 400, and the welding ribbon 800 is also spaced apart from the second edge 702 of the back contact battery to avoid hidden cracks in the battery cell 700 caused by stress concentration when the welding ribbon 800 is welded to the edge of the battery cell 700. Furthermore, the distance from the second end of the second connecting grid line 400 to the second edge 702 is 1 mm to 20 mm. Preferably, the distance from the second end of the second connecting grid line 400 to the second edge 702 is 10 mm to 20 mm. In such an embodiment, the distance from the second end of the second connecting grid line 400 to the second edge 702 can be 10 mm, 15 mm, 20 mm, or any value between 10 mm and 20 mm, and is not specifically limited here.

[0046] The electrode structure also includes a first curved gate line 500 disposed between the busbar 100 and the pad point 200, and a second curved gate line 600 disposed between the busbar 100 and the second connecting gate line 400. In the second direction, the first curved gate line 500 and the second curved gate line 600 are located on either side of the first connecting gate line 300. In the embodiment of the present application, the first curved gate line 500 and the second curved gate line 600 are used to collect opposite-sex carriers between the busbar 100 and the pad point 200, and between the busbar 100 and the second connecting gate line 400, thereby preventing current collection from being lost in these small areas. It is understood that the polarity of the first and second curved gate lines is opposite to that of the busbar and the pad point.

[0047] Furthermore, the first curved gate line 500 is bent toward the busbar 100 and the pad point 200 respectively and does not contact the busbar 100 and the pad point 200, or the first curved gate line 500 is bent toward the busbar 100 and does not contact the busbar 100, or the first curved gate line 500 is bent toward the pad point 200 and does not contact the pad point 200. The length of the first curved gate line 500 is determined according to the size of the arrangable area. The first curved gate line 500 forms a divergent extension, which can arrange the gate lines more evenly, fully utilize the current collectible area, and further improve the current collection capability.

[0048] Furthermore, the second curved gate line 600 is bent toward the main gate 100 and the second connecting gate line 400 respectively and does not contact the main gate 100 or the second connecting gate line 400, or the second curved gate line 600 is bent toward the main gate 100 and does not contact the main gate 100, or the second curved gate line 600 is bent toward the second connecting gate line 400 and does not contact the second connecting gate line 400. The length of the second curved gate line 600 is determined according to the size of the arrangable area. The second curved gate line 600 forms a divergent extension, which can more evenly arrange the gate lines, fully utilize the current collectible area, and further improve the current collection capability.

[0049] In an embodiment of the present application, the main grid 100, the pad point 200, the first connecting grid line 300, the second connecting grid line 400, the first curved grid line 500 and the second curved grid line 600 at the first edge 701 closest to the back contact battery constitute a special electrode structure in a local area of ​​the battery cell 700, so as to realize carrier collection at the edge of the battery cell 700 while avoiding damage to the battery cell 700 caused by the welding ribbon 800 on the pad point 200.

[0050] A battery cell 700 includes the aforementioned electrode structure for a back-contact battery. The beneficial effects obtained by the battery cell 700 in this embodiment are similar to those of the electrode structure, and are not described in detail here.

[0051] The cell 700 includes at least four electrode structures disposed at the four corners of the cell 700. It is understandable that, because the pad points and the main grid at the edges of the cell are separated in the electrode pattern design of this application, when the solder ribbon is laid at the four corners of the cell, it is necessary to respectively provide electrode structures at the four corners of the cell 700 to isolate and protect the cell.

[0052] A solar cell module includes the aforementioned cell 700 and a soldering ribbon 800. The soldering ribbon 800 is connected to the pad 200 and extends along a second direction. The orthographic projection of the soldering ribbon 800 on the cell 700 and the orthographic projection of the second connecting grid line 400 on the cell 700 at least partially overlap. It is understood that the soldering ribbon 800 is connected between multiple cells 700 to form a solar cell module. The soldering ribbon 800 and the second connecting grid line 400 are located on the same straight line. The second connecting grid line 400 can physically isolate the soldering ribbon 800 and also converge carriers to the soldering ribbon 800.

[0053] like Figure 3 and Figure 4 As shown, the welding strip 800 has a free end 801 extending along the second direction toward the second edge 702, and the distance between the free end 801 and the second edge 702 of the back contact battery is greater than the distance between the second end of the second connecting grid line 400 and the second edge 702 of the back contact battery. This ensures that the edge of the welding strip is located on the second connecting grid line, and the second connecting grid line 400 can effectively physically isolate the welding strip 800. Even if there are burrs on the edge of the welding strip 800, it will not come into contact with the fine grid lines. Furthermore, the second connecting grid line 400 includes an extension section 401 and an end section 402. The extension section 401 and the end section 402 are connected, and the width of the end section 402 is greater than the width of the extension section 401. The free end 801 extends to the end section 402, and the width of the end section 402 is greater than the width of the free end. In the present application, the extension section and the end section are integrally formed, and the second connecting grid line 400 is in a T-shaped structure as a whole. In this way, only the portion of the second connecting grid line 400 that contacts the edge of the welding strip 800 is widened and enlarged, thereby achieving physical isolation of the welding strip 800 and reducing the use of slurry for printing the second connecting grid line 400, thereby reducing the production cost of the battery assembly.

[0054] In other embodiments, the width of the second connecting grid line 400 is greater than the width of the soldering ribbon 800. In other words, the width of the second connecting grid line 400 remains constant along its extension direction, and the width of the second connecting grid line 400 is greater than the width of the soldering ribbon 800, further ensuring that the soldering ribbon 800 is completely physically isolated from the battery cell 700, eliminating the possibility of the soldering ribbon 800 piercing the insulating adhesive and connecting to the thin grid lines.

[0055] Throughout this specification, reference to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0056] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. An electrode structure for a back contact battery, characterized in that: include: a busbar closest to the first edge of the back contact cell; A pad point, wherein the pad point and the main gate are spaced apart in a first direction, and a distance between the pad point and the first edge is greater than a distance between the main gate and the first edge; a first connecting gate line, wherein a first end of the first connecting gate line is in electrical contact with the pad point, and a second end of the first connecting gate line is in electrical contact with the main gate; A second connecting gate line, wherein a first end of the second connecting gate line is in electrical contact with the pad point, and a second end of the second connecting gate line extends along a second direction, and the first direction and the second direction intersect.

2. The electrode structure of the back contact battery according to claim 1, wherein: The second end of the second connecting wire extends along the second direction to a second edge of the back contact cell.

3. The electrode structure of the back contact battery according to claim 1, wherein: The second end of the second connecting wire extends along the second direction and is spaced apart from the second edge of the back contact battery.

4. The electrode structure of the back contact battery according to claim 3, characterized in that: The distance from the second end of the second connecting grid line to the second edge is 1 mm to 20 mm.

5. The electrode structure of the back contact battery according to claim 1, wherein: The second connecting gate line includes an extension segment and an end segment, the extension segment and the end segment are connected, and a width of the end segment is greater than a width of the extension segment.

6. The electrode structure of the back contact battery according to claim 1, wherein: It also includes a first curved gate line arranged between the main gate and the pad point, and a second curved gate line arranged between the main gate and the second connecting gate line; in the second direction, the first curved gate line and the second curved gate line are located on both sides of the first connecting gate line.

7. The electrode structure of the back contact battery according to claim 6, characterized in that: The first curved gate line is bent toward the main gate and the pad point respectively and does not contact the main gate and the pad point, or the first curved gate line is bent toward the main gate and does not contact the main gate, or the first curved gate line is bent toward the pad point and does not contact the pad point.

8. The electrode structure of the back contact battery according to claim 6, characterized in that: The second curved gate line is bent toward the main gate and the second connecting gate line respectively and does not contact the main gate and the second connecting gate line, or the second curved gate line is bent toward the main gate and does not contact the main gate, or the second curved gate line is bent toward the second connecting gate line and does not contact the second connecting gate line.

9. A battery cell, characterized in that: An electrode structure comprising a back contact battery according to any one of claims 1 to 8.

10. The battery cell according to claim 9, wherein: The battery cell includes at least four electrode structures respectively arranged at four corners of the battery cell.

11. A solar cell assembly, characterized in that: The battery cell and the welding strip according to claim 9 are included, wherein the welding strip is connected to the pad point and extends along the second direction, and the orthographic projection of the welding strip on the battery cell and the orthographic projection of the second connecting grid line on the battery cell at least partially overlap.

12. The solar cell assembly according to claim 11, wherein The soldering ribbon has a free end extending along the second direction toward the second edge, and a distance from the free end to the second edge of the back contact cell is greater than a distance from the second end of the second connecting wire to the second edge of the back contact cell.

13. The solar cell assembly according to claim 12, wherein: The second connecting gate line includes an extension section and an end section, the extension section and the end section are connected, the width of the end section is greater than the width of the extension section, and the free end extends to the end section, and the width of the end section is greater than the width of the free end.

14. The solar cell assembly according to claim 11, wherein The width of the second connection grid line is greater than the width of the welding strip.

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