Photovoltaic cell test piece and photovoltaic cell test system

Abstract

The utility model provides a photovoltaic cell test piece and a photovoltaic cell test system, and relates to the field of photovoltaic technology. The test piece comprises a battery piece, a plurality of groups of welding strips and two grid line units, the number of each group of welding strips is two, and the two welding strips and the two grid line units are located on the two surfaces of the battery piece respectively; each grid line unit comprises a plurality of grid line structures, each grid line structure comprises a plurality of thin grid lines, and the arrangement direction of the plurality of grid line structures is perpendicular to the arrangement direction of the plurality of thin grid lines; each thin grid line is sequentially provided with a first section, a welding section and a second section, and in every two adjacent grid line structures, the first sections of the thin grid lines in one grid line structure and the second sections of the thin grid lines in the other grid line structure are arranged in an interdigitated mode; the welding sections of the fine grid lines in different grid line structures are different in structure; each welding strip is welded with the welding section of each thin grid line in the same grid line structure, and the positions of the two welding strips in the same group are the same. According to the photovoltaic cell test piece, the test workload is reduced.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic technology, and in particular to a photovoltaic cell test piece and a photovoltaic cell test system. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] Photovoltaic cells are equipped with grid electrodes for collecting photogenerated carriers. Solder ribbons are welded to each grid electrode to form an electrical connection. Multiple cells can be welded together to form a cell string.

[0004] The welding effect between the solder ribbon and the grid electrode significantly impacts the actual conversion efficiency of photovoltaic cells. Developing grid electrodes (layout, paste, etc.) with better welding performance (low series resistance) has become a major focus in the industry. However, in related technologies, the development and testing of photovoltaic cell grid electrodes is quite cumbersome and inefficient. Utility Model Content

[0005] The purpose of this invention is to provide a photovoltaic cell test piece and a photovoltaic cell test system to solve the cumbersome technical problem of developing and testing the grid electrodes of photovoltaic cells.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] In a first aspect, the present invention provides a photovoltaic cell test piece, including a cell, multiple sets of solder ribbons and two grid line units, wherein the two grid line units are respectively disposed on two surfaces of the cell, and each set of solder ribbons consists of two ribbons, which are respectively located on two surfaces of the cell.

[0008] Each of the gate line units includes a plurality of gate line structures arranged along a first direction, and each of the gate line structures includes a plurality of fine gate lines arranged along a second direction, wherein the first direction is perpendicular to the second direction (that is, the arrangement direction of the plurality of gate line structures is perpendicular to the arrangement direction of the plurality of fine gate lines).

[0009] Each of the fine grid lines has a first segment, a welding segment, and a second segment in sequence. In two adjacent grid line structures, the first segment of each fine grid line in one grid line structure and the second segment of each fine grid line in the other grid line structure are arranged in an interdigitated manner.

[0010] The welded sections of the fine grid lines in different grid line structures have different structures;

[0011] Each of the solder strips is welded to the welding segment of each of the fine grid lines in the same grid line structure, and in the first direction, the positions of the two solder strips in the same group are the same.

[0012] According to at least one embodiment of the present invention, the orthographic projections of the two grid units on the surface of the battery cell coincide.

[0013] According to at least one embodiment of the present invention, the two welding strips in each group of welding strips are of the same size and material;

[0014] Alternatively, multiple sets of welding strips may have the same size and material.

[0015] According to at least one embodiment of the present invention, the orthographic projections of the first segment and the second segment on the reference plane are both located within the orthographic projection of the welding segment on the reference plane, and the reference plane is perpendicular to the first direction.

[0016] According to at least one embodiment of the present invention, the welded segment includes a circular or polygonal structure.

[0017] According to at least one embodiment of the present invention, the number of fine grid lines in different grid line structures is the same.

[0018] According to at least one embodiment of the present invention, the polygonal structure includes either a solid structure or a hollow structure.

[0019] According to at least one embodiment of the present invention, the welded segments of the various fine grid lines in the same grid structure are electrically connected or electrically isolated.

[0020] According to at least one embodiment of the present invention, the material of the welding segment of the fine grid line is the same as or different from the material of the first segment and the second segment.

[0021] Secondly, this utility model provides a photovoltaic cell testing system, including a resistance measuring device and the photovoltaic cell test piece described in the first aspect.

[0022] Two of the same group of the photovoltaic cell test pieces are electrically connected to the resistance measuring device; or, multiple photovoltaic cell test pieces are connected to form a cell string through the electrical connection of the first or second solder strip, and the extensions of the first and second solder strips at the same position in the first direction are electrically connected to the resistance measuring device.

[0023] In one or more technical solutions provided in the exemplary embodiments of this utility model, at least one of the following beneficial effects can be achieved.

[0024] The photovoltaic cell test specimen of this exemplary embodiment forms grid line units on both the front and back surfaces of the cell. Each grid line unit includes multiple grid line structures arranged along a first direction, with adjacent grid line structures intersecting in a cross-finger shape. Each grid line structure includes multiple fine grid lines arranged along a second direction, with a welding segment in the middle of each fine grid line. That is, in the first direction, the welding segments of each fine grid line of the same grid line structure are at the same position and are electrically connected by a welding strip. A welding strip is present at the same position in the first direction on both sides of the cell, forming a set of welding strips. The resistance of the grid line structure containing this set of welding strips can be accurately measured using a resistance measuring device.

[0025] Furthermore, since the welding sections of the fine grid lines in different grid line structures have different structures, multiple grid line structures are formed on the same solar cell through an alloying process. Multiple sets of solder ribbons are used to weld the fine grid lines in different grid line structures to form electrical connections, ensuring a consistent manufacturing environment for the photovoltaic cell test piece. This allows for comparison of the contact resistance of each grid line structure, thereby selecting a suitable grid line structure. Based on this, the photovoltaic cell test piece of this exemplary embodiment can reduce the workload of testing and evaluation, improve work efficiency, and, because each grid line structure is prepared using the same manufacturing environment, the resistance data comparison between the various grid line structures is more accurate. Attached Figure Description

[0026] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification.

[0027] Figure 1 This is a structural schematic diagram of a photovoltaic cell test piece according to an embodiment of the present invention;

[0028] Figure 2 This is a structural schematic diagram of a photovoltaic cell test piece (without solder strips) according to an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the first grid line structure according to an embodiment of the present utility model;

[0030] Figure 4 This is a schematic diagram of the second grid line structure according to an embodiment of the present utility model;

[0031] Figure 5 This is a schematic diagram of the third grid line structure according to an embodiment of the present utility model;

[0032] Figure 6This is a schematic diagram of the fourth grid line structure according to an embodiment of the present utility model;

[0033] Figure 7 This is a schematic diagram of the fifth grid line structure according to an embodiment of the present utility model;

[0034] Figure 8 This is a schematic diagram of the sixth grid line structure according to an embodiment of the present utility model;

[0035] Figure 9 This is a schematic diagram of the seventh grid line structure according to an embodiment of the present utility model;

[0036] Figure 10 This is a schematic diagram of the eighth grid line structure according to an embodiment of the present invention.

[0037] Reference numerals: 10, solar cell; 21, first solder strip; 22, second solder strip; 30, fine grid line; 31, first segment; 32, second segment; 33, welding segment; 301, first grid line structure; 302, second grid line structure; 303, third grid line structure; 304, fourth grid line structure; 305, fifth grid line structure; 306, sixth grid line structure; 307, seventh grid line structure; 308, eighth grid line structure. Detailed Implementation

[0038] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0039] In related technologies, photovoltaic cell grid layouts vary greatly and there are many ways to implement welding schemes. Whether it is traditional welding methods or coating welding technology (adhesive / curing) in gridless technology, it is impossible to avoid alloying and evaluating the contact resistance caused by alloying. Moreover, the verification of alloying effect is often complicated (multiple comparisons). There are inconsistencies in the photovoltaic cell test component manufacturing environment (welding environment), resulting in poor comparability of comparative data. Therefore, even after complicated testing, it is still impossible to accurately characterize the quality of the grid structure.

[0040] To address the aforementioned issues, the photovoltaic cell test piece provided by the exemplary embodiment of this utility model forms identical grid line units on both the front and back surfaces of the cell. The grid line units are composed of different grid line structures, such as different structures for the welding segments of the fine grid lines in the grid line structures. Furthermore, different grid line structures are integrated onto a single cell using the same manufacturing process, thereby enabling the rapid selection of the optimal grid line structure.

[0041] The photovoltaic cell test piece of the exemplary embodiment of this utility model is applicable to various crystalline silicon structure cells, and is also applicable to the evaluation of the grid line welding performance of any photovoltaic cell.

[0042] Figure 1 This is a structural schematic diagram of a photovoltaic cell test piece according to an embodiment of the present invention; Figure 2 This is a structural schematic diagram of a photovoltaic cell test piece (without solder strips) according to an embodiment of this utility model. Figure 1 and Figure 2 As shown, in the photovoltaic cell test specimen of the exemplary embodiment of the present invention, grid line units with the same structure are formed on the front and back surfaces of the cell 10 through the same process.

[0043] For ease of description, the solder strip on the front side of the solar cell 10 is referred to as the first solder strip 21, and the solder strip on the back side is referred to as the second solder strip 22, as follows: Figure 2 As shown, the multiple grid structures arranged sequentially from left to right are called the first grid structure 301, the second grid structure 302, the third grid structure 303, the fourth grid structure 304, the fifth grid structure 305, and the sixth grid structure 306. A first solder ribbon 21 is provided on each grid structure on the front side of the solar cell 10. At the same position in the first direction, a second solder ribbon 22 corresponding to the first solder ribbon 21 is provided on the back side of the solar cell 10. The corresponding first solder ribbon 21 and second solder ribbon 22 form a set of solder ribbons. In the second direction, the first solder ribbon 21 extends outward from one side of the solar cell 10 to form an extension segment, and the second solder ribbon 22 extends outward from the opposite side of the solar cell 10 to form an extension segment. By measuring the extension segments of the first solder ribbon 21 and the second solder ribbon 22, the series resistance of the fine grid lines 30 in this grid structure can be obtained.

[0044] The following section uses the first gate line structure 301 and the second gate line structure 302 as examples to illustrate the gate line unit.

[0045] Figure 3 This is a schematic diagram of the first grid line structure according to an embodiment of the present utility model; Figure 4 This is a schematic diagram of the second grid line structure according to an embodiment of the present invention. Figure 3 and Figure 4 As shown, each grid structure includes multiple fine grid lines 30 arranged along the second direction, and each fine grid line 30 sequentially has a first segment 31, a welding segment 33, and a second segment 32. Figure 2As shown, in two adjacent gate line structures, such as the first gate line structure 301 and the second gate line structure 302, along the second direction, the second segment 32 of each fine gate line 30 in the first gate line structure 301 and the first segment 31 of each fine gate line 30 in the second gate line structure 302 are arranged in an interdigital pattern and electrically isolated.

[0046] For example, the number of fine gate lines 30 in the first gate structure 301 is the same as the number of fine gate lines 30 in the second gate structure 302.

[0047] On the front side of the solar cell 10, the welded segments 33 of each fine grid line 30 in the first grid structure 301 have the same structure and position, and are electrically connected after being welded by the first solder strip 21. The structure of the welded segments 33 of each fine grid line 30 in the second grid structure 302 is different from that in the first grid structure 301. Based on this, two different grid structures are formed on the same solar cell 10 for comparative evaluation.

[0048] On the back side of the battery cell 10, the first grid structure 301 and the second grid structure 302 are the same as those on the front side, and the welding segments 33 of each fine grid line 30 in the first grid structure 301 and the welding segments 33 of each fine grid line 30 in the second grid structure 302 are respectively welded to form an electrical connection by the corresponding second welding strip 22.

[0049] In practical applications, by extending the corresponding first solder ribbon 21 and second solder ribbon 22 out of the corresponding extensions of the solar cell 10, and measuring their series resistance using a resistance measuring device, the performance of the first grid structure 301 and the second grid structure 302 can be evaluated by comparing their resistance values. It is understood that a lower resistance value indicates a better welding effect of the grid structure and a higher photoelectric conversion efficiency. Since the first grid structure 301 and the second grid structure 302 are formed in the same process environment, compared to the prior art which uses different solar cells 10 to form the grid structure, the influence of process factors can be eliminated, thus enabling accurate comparison of resistance values ​​without the need for multiple experiments.

[0050] The arrangement of other gate line structures in the aforementioned gate line unit (including the third gate line structure 303, the fourth gate line structure 304, the fifth gate line structure 305, and the sixth gate line structure 306, such as...) Figure 2 , Figures 5-8 As shown), whether on the front or back, the arrangement is consistent with the first grid line structure 301 and the second grid line structure 302, arranged in an interlaced finger pattern from left to right, which will not be described in detail here.

[0051] In some implementations, the orthographic projections of the two grid cells on the surface of the cell 10 coincide, which can ensure the accuracy of the measured resistance data and eliminate data deviations that may be caused by grid pattern misalignment.

[0052] To eliminate the influence of solder ribbon size and material on measurement data, the two solder ribbons (first solder ribbon 21 and corresponding second solder ribbon 22) in the same group are identical in size and material. For example, all first solder ribbons 21 and second solder ribbons 22 are identical in size and material.

[0053] In some embodiments, the material of the welding segment 33 in the same fine grid line 30 is the same as that of the first segment 31 and the second segment 32. For example, the same fine grid line 30 is formed using silver paste.

[0054] In another alternative embodiment, the material of the welding segment 33 in the same fine grid line 30 is different from the materials of the first segment 31 and the second segment 32. For example, in the same fine grid line 30, the welding segment 33 is formed using silver-aluminum paste, while the first segment 31 and the second segment 32 are formed using silver paste.

[0055] In some embodiments, the orthographic projections of the first segment 31 and the second segment 32 on the reference plane are both located within the orthographic projection of the welding segment 33 on the reference plane, and the reference plane is perpendicular to the first direction.

[0056] The first segment 31 and the second segment 32 are linear structures, while the welding segment 33 is a polygonal or circular structure with a larger cross-sectional area, so that it can make full contact with the welding strip when welding, and minimize the occurrence of welding defects.

[0057] For example, the shape of the polygonal structure includes either a rectangle or a rhombus.

[0058] For example, the polygonal structure includes either a solid structure or a hollow structure.

[0059] For example, the welded segments 33 of the individual fine grid lines 30 in the same grid structure are electrically connected or electrically isolated from each other.

[0060] like Figure 3 As shown, the welding segment 33 in the first grid structure 301 is a hollow rhomboid structure, and each welding segment 33 is electrically isolated from the others.

[0061] like Figure 4 As shown, the welding section 33 in the second grid structure 302 is a hollow rhomboid structure, and each welding section 33 is electrically connected to the other through the grid lines.

[0062] Figure 5 This is a schematic diagram of the third grid line structure according to an embodiment of the present utility model; Figure 6This is a schematic diagram of the fourth grid line structure according to an embodiment of the present utility model; Figure 7 This is a schematic diagram of the fifth grid line structure according to an embodiment of the present utility model; Figure 8 This is a schematic diagram of the sixth grid line structure according to an embodiment of the present invention. Figures 3-8 As shown, all welded sections 33 are hollow structures.

[0063] Specifically, such as Figure 5 The welding segment 33 in the third grid structure 303 shown is a hollow rhomboid structure. Two adjacent welding segments 33 are electrically connected by grid lines to form a group of welding segments 33. The welding segments 33 in different groups are electrically isolated from each other.

[0064] like Figure 6 The welding segment 33 in the fourth grid structure 304 shown is a hollow rectangular structure with a variable cross-section. Two adjacent welding segments 33 are electrically connected by grid lines to form a group of welding segments 33, and welding segments 33 in different groups are electrically isolated from each other.

[0065] like Figure 7 The welding segment 33 in the fifth grid structure 305 shown is a hollow rectangular structure. Two adjacent welding segments 33 are electrically connected by grid lines to form a group of welding segments 33. Different groups of welding segments 33 are electrically isolated from each other.

[0066] like Figure 8 The welding segment 33 in the sixth grid structure 306 shown is a hollow rhomboid structure. Each welding segment 33 is electrically connected by a grid line, and there is a circular dot structure (conductor) at the center of the welding segment 33.

[0067] Figure 9 This is a schematic diagram of the seventh grid line structure according to an embodiment of the present utility model; Figure 10 This is a schematic diagram of the eighth grid line structure according to an embodiment of the present invention. Figures 9-10 As shown, all welded sections 33 are solid structures.

[0068] Specifically, such as Figure 9 The welding segment 33 of the seventh grid structure 307 shown is a solid rhomboid structure. Every three welding segments 33 form a group of welding segments 33 that are electrically connected through the grid line. After a gap of one welding segment 33, another three welding segments 33 form another group of welding segments 33 that are electrically connected through the grid line. Both groups of welding segments 33 are electrically isolated from the welding segment 33 located between them.

[0069] like Figure 10 The welding segment 33 of the eighth grid line structure 308 shown is a solid rectangular structure, which can also be regarded as a thickened structure of the thin grid line 30. The welding segments 33 are electrically connected to each other through the grid line.

[0070] As can be seen from the above, the photovoltaic cell test piece of the exemplary embodiment of this utility model can achieve performance evaluation of different grid structures by printing grid line structures with different structures on the cell 10, and having the same grid line units and solder strips on both the front and back sides, and by measuring the series resistance of the first solder strip 21 and the second solder strip 22 located at the same position in the first direction.

[0071] An exemplary embodiment of this utility model also provides a photovoltaic cell testing system, including a resistance measuring device and a photovoltaic cell test piece according to the above embodiment, wherein two solder strips of the same group of the photovoltaic cell test piece are electrically connected to the resistance measuring device.

[0072] For example, there are multiple photovoltaic cell test pieces. Multiple photovoltaic cell test pieces are connected by the first solder strip 21 or the second solder strip 22 to form a cell string. Then, by measuring the resistance between the extension of the first solder strip 21 and the extension of the second solder strip 22 at the same position in the first direction, the welding effect of the grid structure after the cell string is formed is judged.

[0073] It is understandable that the grid structure of each cell in the same battery string is exactly the same at the same position in the first direction. Therefore, by comparing the resistance values, the quality of the battery string formed by multiple grid structures can be judged.

[0074] The technological advantages of the aforementioned photovoltaic cell testing system compared to existing technologies are the same as those of the aforementioned photovoltaic cell test pieces, and will not be repeated here.

[0075] Those skilled in the art should understand that the above embodiments are merely for clearly illustrating the present invention and are not intended to limit the scope of the present invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A photovoltaic cell test piece, characterized in that, It includes a solar cell, multiple sets of solder ribbons and two grid line units. The two grid line units are respectively disposed on two surfaces of the solar cell. Each set of solder ribbons consists of two ribbons, which are respectively located on two surfaces of the solar cell. Each of the gate line units includes a plurality of gate line structures arranged along a first direction, and each of the gate line structures includes a plurality of fine gate lines arranged along a second direction, wherein the first direction is perpendicular to the second direction; Each of the fine grid lines has a first segment, a welding segment, and a second segment in sequence. In two adjacent grid line structures, the first segment of each fine grid line in one grid line structure and the second segment of each fine grid line in the other grid line structure are arranged in an interdigitated manner. The welded sections of the fine grid lines in different grid line structures have different structures; Each of the solder strips is welded to the welding segment of each of the fine grid lines in the same grid line structure, and in the first direction, the positions of the two solder strips in the same group are the same.

2. The photovoltaic cell test piece according to claim 1, characterized in that, The orthographic projections of the two grid units on the surface of the solar cell coincide.

3. The photovoltaic cell test piece according to claim 1, characterized in that, The two weld strips in each group are of the same size and material; Alternatively, multiple sets of welding strips may have the same size and material.

4. The photovoltaic cell test piece according to claim 1, characterized in that, The orthographic projections of the first segment and the second segment onto the reference plane are both located within the orthographic projection of the welding segment onto the reference plane, and the reference plane is perpendicular to the first direction.

5. The photovoltaic cell test piece according to claim 4, characterized in that, The welded section includes either a circular or polygonal structure.

6. The photovoltaic cell test piece according to claim 5, characterized in that, The polygonal structure includes either a solid structure or a hollow structure.

7. The photovoltaic cell test piece according to claim 1, characterized in that, The number of fine grid lines is the same in different grid line structures.

8. The photovoltaic cell test piece according to any one of claims 1-7, characterized in that, The welded segments of the individual fine grid lines in the same grid line structure are electrically connected or electrically isolated.

9. The photovoltaic cell test piece according to claim 8, characterized in that, The material of the welded section of the fine grid line is the same as or different from the material of the first section and the second section.

10. A photovoltaic cell testing system, characterized in that, Includes a resistance measuring device and a photovoltaic cell test piece as described in any one of claims 1-9. Two of the same group of the photovoltaic cell test pieces are electrically connected to the resistance measuring device; or, multiple photovoltaic cell test pieces are connected to form a cell string through the electrical connection of the first or second solder strip, and the extensions of the first and second solder strips at the same position in the first direction are electrically connected to the resistance measuring device.

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