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

Abstract

The invention 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 that place both the emitter and base contact electrodes 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. This unobstructed front-side cell 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 strips are connected to the pad points away from the edge of the cell, avoiding the stress concentration caused by setting the welding strips 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 edges of the welding strips after cutting, when the welding strips are set on the cell, the burrs on the edges of the welding strips can easily pierce the insulating glue, causing the welding strips to connect with the opposite grid lines, and there is a risk of local short circuit in the cell.

[0004] Application Contents

[0005] The present application provides a solar cell, aiming 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 battery cell, the burrs on the edge of the soldering ribbon are easy to pierce the insulating glue, causing the soldering ribbon to be connected to the opposite grid line, and there is a risk of local short circuit in the battery cell.

[0006] The present application is implemented as follows: an electrode structure of a back contact battery, comprising:

[0007] a busbar closest to a first edge of the back contact cell;

[0008] A pad point, wherein the pad point and the main grid 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 grid and the first edge;

[0009] 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;

[0010] A second connecting gate line, a first end of the second connecting gate line is electrically contacted with the pad point, a second end of the second connecting gate line extends along a second direction, and the first direction intersects with the second direction.

[0011] Optionally, the second end of the second connecting grid line extends along the second direction to a second edge of the back contact cell.

[0012] Optionally, the second end of the second connecting grid line extends along the second direction and is spaced apart from a second edge of the back contact battery.

[0013] Optionally, a distance from the second end of the second connecting grid line to the second edge is 1 mm to 20 mm.

[0014] 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.

[0015] Optionally, 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.

[0016] 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.

[0017] 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.

[0018] The present application sets a pad point and a second connecting grid line connected to the pad point. When the welding strip is set on the battery cell and connected to the pad point, the welding strip extends to the second connecting grid line, so that the burrs on the edge of the welding strip are blocked by the second connecting grid line, which avoids the burrs on the edge of the welding strip from directly piercing the insulating glue and connecting with the opposite 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.

[0019] A battery cell includes the electrode structure of the back-contact battery. The technical effect of the present application is the same as the technical effect of the electrode structure of the back-contact battery, which will not be repeated here.

[0020] Optionally, the battery cell includes at least four electrode structures respectively arranged at four corners of the battery cell.

[0021] A solar cell module comprises the above-mentioned cell sheet and a welding strip, 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 cell sheet and the orthographic projection of the second connecting grid line on the cell sheet at least partially overlap.

[0022] Optionally, the welding strip 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 grid line to the second edge of the back contact battery.

[0023] Optionally, the second connecting gate line includes an extension section and an end section, the extension section is connected to the end section, 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.

[0024] Optionally, the width of the second connecting grid line is greater than the width of the welding strip.

[0025] 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, on 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, 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

[0026] Figure 1 It is a structural schematic diagram of the electrode structure of the first back contact battery provided in the present application;

[0027] Figure 2 It is a structural schematic diagram of the first solar cell assembly provided in the present application;

[0028] Figure 3 It is a schematic structural diagram of the electrode structure of the second back contact battery provided in the present application;

[0029] Figure 4 It is a schematic diagram of the structure of the second solar cell assembly provided in the present application.

[0030] Description of reference numerals:

[0031] 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

[0032] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with 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 should not be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0033] In the description of the present 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, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0034] 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. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0037] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0038] like Figure 1-Figure 4 As shown, an electrode structure of a back contact battery includes a main grid 100 , a pad point 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 .

[0039] 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 central main grid. In the arrangement structure of the main grid 100 in the battery cell 700, the edge main grid and the central 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 arrangement of the welding strip 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 strip 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.

[0040] Therefore, in the embodiment of the present application, a second connecting grid line 400 is arranged on the battery cell 700 to connect with the pad point, and the second connecting grid line 400 is arranged in parallel with the main grid 100, and the second connecting grid line 400 is also consistent with the extension direction of the welding strip 800. In this way, when the welding strip 800 is welded on the battery cell 700, the welding strip 800 and the fine grid line area are isolated by the second connecting grid line 400, and even if there are burrs on the edge of the welding strip 800, the welding strip 800 is isolated by the second connecting grid line 400 and cannot form electrical conduction with the fine grid line.

[0041] The second connecting grid line 400 can be formed by printing a metal paste on the surface of the battery cell 700 by screen printing, so as to form the second connecting grid line 400 on the surface of the battery cell 700. The metal paste can be a silver paste, an aluminum paste, etc. Here, there is no restriction on the specific material of the metal paste. In actual use, the technician can select a suitable material according to the needs. Similarly, the edge main grid 100 and the first connecting grid line 300 can also be prepared in the above manner, which will not be repeated here.

[0042] In some embodiments, specifically, in order to effectively collect the carriers at the edge of the battery cell 700, the main grid 100 must be set at the edge of the battery cell 700 to converge the carriers collected by the fine grid lines at the edge and then lead them out through the welding strip 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 welding strip 800 is arranged on the edge pad point 200, it is very easy to cause hidden cracks in the battery cell 700. To improve this disadvantage, the pad point 200 and the main grid 100 are arranged at intervals 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 arranged between the pad point 200 and the main grid 100 for carrier convergence, a first end of the first connecting grid line 300 is in electrical contact with the pad point 200, and a second end of the first connecting grid line 300 is in electrical contact with the main grid 100. Such an electrode pattern design effectively solves the hidden danger of the battery cell 700 being cracked due to the arrangement of the welding strip 800 at the edge of the battery cell 700.

[0043] 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 in electrical contact 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 through. 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. Exemplarily, 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 arranged relatively in the first direction, and the second edge 702 is the edge of the battery cell 700 arranged relatively in the second direction.

[0044] The present application sets a pad point 200 and a second connecting grid line 400 connected to the pad point 200. 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, which prevents 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.

[0045] 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 battery. In this way, on the one hand, the second connecting grid line 400 can carry out carrier convergence of fine grid lines in a larger area, and on the other hand, the welding strip 800 can also extend to the second edge 702 of the back contact battery along with the second connecting grid line 400. Such a design reduces the transmission path of the current inside the battery cell 700, reduces the resistance loss, and thus improves the current transmission efficiency.

[0046] 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 strip 800 is stacked on the second connecting grid line 400, and the welding strip 800 is also spaced apart from the second edge 702 of the back contact battery to avoid the hidden cracks of the battery cell 700 caused by stress concentration when the welding strip 800 is welded to the edge of the battery cell 700. Further, the distance from the second end of the second connecting grid line 400 to the second edge 702 is 1mm to 20mm. Preferably, the distance from the second end of the second connecting grid line 400 to the second edge 702 is 10mm to 20mm. In such an embodiment, the distance from the second end of the second connecting grid line 400 to the second edge 702 can be 10mm, 15mm, 20mm, or any value between 10mm-20mm, which is not specifically limited here.

[0047] The electrode structure also includes a first curved gate line 500 disposed between the main gate 100 and the pad point 200, and a second curved gate line 600 disposed between the main gate 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 both sides 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 carriers between the main gate 100 and the pad point 200 and between the main gate 100 and the second connecting gate line 400, so as to avoid the failure of current collection in this small area. It can be understood that the polarity of the first curved gate line and the second curved gate line is opposite to the polarity of the main gate and the pad point.

[0048] Further, the first curved gate line 500 is bent toward the main gate 100 and the pad point 200 respectively and does not contact the main gate 100 and the pad point 200, or the first curved gate line 500 is bent toward the main gate 100 and does not contact the main gate 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, make full use of the current collectible area, and further improve the current collection capability.

[0049] Further, 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 and 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 arrange the gate lines more evenly, make full use of the current collectible area, and further improve the current collection capability.

[0050] In the 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 the local area of ​​the battery cell 700 to achieve 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.

[0051] A battery cell 700 includes the electrode structure of the back contact battery. The beneficial effects obtained by the battery cell 700 in this embodiment are similar to the beneficial effects of the electrode structure, which will not be described in detail here.

[0052] The cell 700 includes at least four electrode structures respectively arranged at the four corners of the cell 700. It can be understood that, since the pad point and the main grid at the edge of the cell are separately arranged in the electrode pattern design of the present application, when the welding strip is laid at the four corners of the cell, it is necessary to respectively arrange the electrode structures at the four corners of the cell 700 to isolate and protect the cell.

[0053] A solar cell module includes the above-mentioned cell sheet 700 and a welding strip 800, wherein the welding strip 800 is connected to the pad point 200 and extends along the second direction, and the orthographic projection of the welding strip 800 on the cell sheet 700 and the orthographic projection of the second connecting grid line 400 on the cell sheet 700 at least partially overlap. It can be understood that the welding strip 800 is connected between a plurality of cell sheets 700 to form a solar cell module. The welding strip 800 and the second connecting grid line 400 are located on the same straight line, and the second connecting grid line 400 can physically isolate the welding strip 800, and at the same time, the second connecting grid line 400 can also converge carriers to the welding strip 800.

[0054] 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 from the free end 801 to the second edge 702 of the back contact battery is greater than the distance from the second end of the second connecting grid line 400 to the second edge 702 of the back contact battery. In this way, it can be ensured that the edge of the welding strip is located on the second connecting grid line, and the second connecting grid line 400 can effectively play a physical isolation effect on the welding strip 800, and even if there are burrs on the edge of the welding strip 800, it will not form contact with the thin grid line. Further, 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, the width of the end section 402 is greater than the width of the extension section 401, and 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 an overall T-shaped structure, so that only the portion where the second connecting grid line 400 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.

[0055] In other embodiments, the width of the second connecting grid line 400 is greater than the width of the welding strip 800. In other words, the width of the second connecting grid line 400 remains unchanged in its extension direction, and the width of the second connecting grid line 400 is greater than the width of the welding strip 800, further ensuring that the welding strip 800 is completely physically isolated from the battery cell 700, eliminating the possibility of the welding strip 800 piercing the insulating glue and connecting with the thin grid line.

[0056] In the description of this specification, the description with reference to the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are 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. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0057] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. An electrode structure of a back contact battery, characterized in that: include: a busbar closest to a first edge of the back contact cell; A pad point, wherein the pad point and the main grid 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 grid 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, a first end of the second connecting gate line is electrically contacted with the pad point, 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, characterized in that: 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, characterized in that: The second end of the second connecting grid line 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, characterized in that: The second connecting gate line includes an extension section and an end section, the extension section and the end section are connected, and the width of the end section is greater than the width of the extension section.

6. The electrode structure of the back contact battery according to claim 1, characterized in that: 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 as described in any one of claims 1 to 8.

10. The battery cell according to claim 9, characterized in that: 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: It includes the battery cell and the welding strip as described in claim 9 above, 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, characterized in that: The soldering strip 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, characterized in that: The second connecting gate line includes an extension section and an end section, the extension section is connected to the end section, 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, characterized in that: The width of the second connection grid line is greater than the width of the welding strip.

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