Electrode structure of back contact battery, back contact battery and back contact battery assembly

Abstract

The utility model is suitable for the field of photovoltaic technology, and provides an electrode structure of a back contact battery, the back contact battery and a back contact battery assembly. The main grid is arranged on one side, close to the edge, of the back contact battery; one end of the connecting grid line is in electric contact with the pad point, and the other end of the connecting grid line is in electric contact with the main grid; the pad point, the main grid, the connecting grid line and the thin grid are arranged in parallel, the pad point, the main grid, the connecting grid line and the thin grid are identical in property, the thin grid is arranged between the pad point and the main grid and used for collecting photo-generated electron holes in the area where the connecting grid line is located, and the photo-generated electron holes do not need to be transmitted across a long distance; according to the back contact cell, the transmission loss of carriers is reduced, the photoelectric conversion efficiency of the back contact cell can be further improved, in addition, the carriers between the pad points and the main grids can be transmitted through the fine grids, and the transmission efficiency of the carriers is further 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 back-contact cell, and a back-contact cell assembly. Background Art

[0002] In the related art, the back contact battery has its electrode structure arranged on the back of the battery. In order to improve the performance of the battery, the utilization rate of the PN area needs to be increased as much as possible during the battery structure design process, such as Figure 1 As shown, generally, the pad point is connected to the continuous main grid through a single connecting gate line of the same polarity to achieve convergence. In this way, the photogenerated electrons and holes in the polarity area where the single connecting gate line is located need to diffuse to the opposite polarity area to form effective collection. The photogenerated electrons and holes in the polarity area corresponding to the single connecting gate line need to cross a distance of mm or even cm to reach the same polarity gate line. The recombination loss in the long-distance diffusion process will cause the short-circuit current to decrease, and will increase the series resistance, causing the loss of fill factor, resulting in very poor photoelectric conversion performance.

[0003] Application Contents

[0004] The present application provides a solar cell, which aims to solve the problem that photogenerated electrons and holes in the polarity region corresponding to a single connected grid line need to cross a distance of mm or even cm to reach the opposite polarity region. The recombination loss in the long-distance diffusion process will cause the short-circuit current to decrease, and increase the string resistance, causing the fill factor loss, resulting in very poor photoelectric conversion performance.

[0005] The present application is implemented as follows: an electrode structure of a back-contact battery includes a pad point; a main grid, the main grid is arranged on the side of the back-contact battery close to the edge; a connecting grid line, one end of the connecting grid line is electrically contacted with the pad point, and the other end of the connecting grid line is electrically contacted with the main grid; a fine grid, the fine grid and the connecting grid line are arranged in parallel, one end of the fine grid is electrically contacted with the pad point, and the other end of the fine grid is electrically contacted with the main grid; wherein the pad point, the main grid, the connecting grid line and the fine grid have the same properties.

[0006] Optionally, the connecting gate line includes at least a first gate line and a second gate line, the first gate line and the second gate line are arranged in parallel and spaced apart, the fine gate is arranged between the first gate line and the second gate line, and both ends of each of the first gate line and the second gate line are respectively connected to the pad point and the main gate.

[0007] Optionally, in the thickness direction of the back contact cell, the height of the fine grid is smaller than the height of the first grid line or the second grid line.

[0008] Optionally, the center line of the fine grid passes through the center point of the pad point.

[0009] Optionally, the width of the first gate line is at least less than or equal to 1 / 2 of the main gate.

[0010] Optionally, the width of the second gate line is at least smaller than or equal to 1 / 2 of the main gate.

[0011] Optionally, the first gate line and the second gate line have the same width.

[0012] Optionally, the spacing distance between the first grid line and the second grid line is 0.01 mm-0.2 mm.

[0013] Optionally, the width of the fine grid is in the range of 0.02 mm to 0.1 mm.

[0014] Optionally, the width of the first gate line or the second gate line is greater than the width of the fine gate.

[0015] Optionally, the distance between the center of the pad point and the edge is 1 mm-10 mm.

[0016] Optionally, the distance between the center line of the main grid and the edge is 0.1 mm-0.5 mm.

[0017] The present application includes a pad point, a main grid, and a connecting grid line arranged between the pad point and the main grid. A fine grid is arranged between the pad point and the main grid to collect photogenerated electrons and holes in the area where the connecting grid line is located. The photogenerated electrons and holes do not need to be transmitted across a long distance, which reduces the transmission loss of the carriers and thereby improves the photoelectric conversion efficiency of the back contact battery. In addition, the fine grid can also transmit carriers between the pad point and the main grid, thereby improving the carrier transmission efficiency.

[0018] A solar cell comprises the above-mentioned solar cell electrode structure.

[0019] A solar cell assembly comprises the above-mentioned solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the electrode structure of a back contact battery in the prior art;

[0021] Figure 2 This is a schematic structural diagram of the electrode structure of the first back-contact battery provided in the present application;

[0022] Figure 3 This is a schematic structural diagram of the electrode structure of the second back contact battery provided in the present application;

[0023] Figure 4This is a schematic structural diagram of the electrode structure of the third back-contact battery provided in the present application;

[0024] Figure 5 yes Figure 4 Schematic diagram of the cross-sectional structure in the AA direction.

[0025] Description of reference numerals:

[0026] 100, pad point; 200, main gate; 300, connecting gate line; 301, first gate line; 302, second gate line; 400, fine gate; 500, edge. DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] An electrode structure of a back-contact battery includes a pad 100 , a main grid 200 , a connecting grid line 300 and a fine grid 400 .

[0034] like Figure 2 and Figure 3As shown, in the embodiment of the present application, the main grid 200 is arranged on the side of the back contact battery near the edge 500, one end of the connecting grid line 300 is electrically contacted with the pad point 100, and the other end of the connecting grid line 300 is electrically contacted with the main grid 200. The connecting grid line 300 is used to transfer the carriers on the main grid 200 arranged near the edge of the back contact battery to the pad point 100, and then converge them out through the welding strip on the pad point 100. The connecting grid line 300 here is usually printed using a non-burn-through paste and only has the function of transmitting carriers. It is unable to collect the carriers located in the polar region within the area where the connecting grid line 300 is located, resulting in carrier loss in the local area of ​​the battery cell. Even if the photogenerated electrons and holes in the corresponding polar region reach the same-polarity grid line across a distance of mm or even cm, the carriers are recombined in large quantities during the long-distance diffusion process and are almost completely consumed. Therefore, the present application sets a fine gate 400 between the pad point 100 and the main gate 200. The fine gate 400 and the connecting gate line 300 are arranged in parallel. One end of the fine gate 400 is in electrical contact with the pad point 100, and the other end of the fine gate 400 is in electrical contact with the main gate 200. The pad point 100, the main gate 200, the connecting gate line 300 and the fine gate 400 have the same polarity, thereby preventing the recombination of carriers of different polarities on the fine gate 400 and the connecting gate line 300, and ensuring the effective transmission of carriers of the same polarity on the fine gate 400 and the connecting gate line 300. Here, the fine gate 400 is printed using a burn-through slurry. During the sintering process, the fine gate 400 burns through the passivation film layer to achieve ohmic contact with the polar region, thereby effectively collecting the photogenerated carriers in the corresponding polarity region.

[0035] In addition, the fine grid 400 and the connecting grid line 300 are arranged in parallel to facilitate printing of the fine grid 400. There is no limit to the relative position between the fine grid 400 and the connecting grid line 300. For example, the fine grid 400 can be arranged above the connecting grid line 300, or below the connecting grid line 300. Furthermore, the fine grid 400 can also be arranged on the connecting grid line 300, directly burning through the connecting grid line 300 and the passivation film layer together to contact the polar region. This application does not impose any restrictions on this. The fine grid 400 can be arranged according to the design requirements of the actual electrode pattern. It is sufficient that the fine grid 400 can collect carriers in the polar region of the area where the connecting grid line 300 is located.

[0036] like Figure 4As shown, preferably, the connecting grid line 300 includes at least a first grid line 301 and a second grid line 302, the first grid line 301 and the second grid line 302 are arranged in parallel and spaced apart, the fine grid 400 is arranged between the first grid line 301 and the second grid line 302, and the two ends of each of the first grid line 301 and the second grid line 302 are respectively connected to the pad point 100 and the main grid 200. In the embodiment of the present application, the fine grid 400 is arranged in the gap between the first grid line 301 and the second grid line 302. On the one hand, it can better realize the collection of carriers in the area where the connecting grid line 300 is located, so that the carriers in the area where the connecting grid line 300 is located have the shortest transmission path. On the other hand, the arrangement of the fine grid 400 will not damage the connecting grid line 300. The first grid line 301 and the second grid line 302 serve as the main current transmission path. Their parallel and spaced arrangement can ensure the uniform distribution and effective transmission of current on the battery cell.

[0037] Furthermore, the centerline of the fine grid 400 passes through the center of the pad 100. The fine grid 400 line acts as a tiny channel for current collection, and its centerline passing through the center of the pad 100 ensures that the current transmission path from the cell surface to the pad 100 is the shortest and most direct. This reduces current loss during transmission and improves current collection efficiency. Furthermore, the design of the fine grid 400 line center passing through the center of the pad 100 facilitates a more compact and efficient grid line layout, improving the overall performance and reliability of the cell. Furthermore, this design makes the alignment process more intuitive and simple, reducing manufacturing difficulty and cost.

[0038] In other embodiments, the width of the first grid line 301 is at least less than or equal to 1 / 2 of the main grid 200, and the width of the second grid line 302 is at least less than or equal to 1 / 2 of the main grid 200. Furthermore, the ratio of the first grid line 301 to the main grid 200 is greater than or equal to 1 / 4 and less than or equal to 1 / 2, and the ratio of the second grid line 302 to the main grid 200 is greater than or equal to 1 / 4 and less than or equal to 1 / 2. The first grid line 301 and the second grid line 302 mainly play a role in current transmission. The width of the first grid line 301 and the second grid line 302 is within this range. On the one hand, it can provide a certain contact area, making the welding of the first grid line 301 and the second grid line 302 to the solar cell more secure, reducing problems such as empty welding and cold welding that may occur during the welding process, thereby improving welding efficiency and welding quality. In addition, the first grid line 301 and the second grid line 302 are within this range to ensure that the current maintains a low resistance during the transmission process, reducing heat loss and power loss caused by excessive resistance.

[0039] Preferably, the width of the first gate line 301 is 1 / 2 of the width of the main gate 200, and the width of the second gate line 302 is 1 / 2 of the width of the main gate 200. The first gate line 301 and the second gate line 302 have the same width. In this way, the sum of the widths of the first gate line 301 and the second gate line 302 can be consistent with the width of the main gate 200, thereby avoiding increased manufacturing costs or other adverse effects due to the use of two connected first gate lines 301 and second gate lines 302.

[0040] Preferably, the width of the first grid line is 0.15 mm to 0.3 mm, and the width of the second grid line is 0.15 mm to 0.3 mm. It can be understood that the width of the first grid line or the second grid line is greater than the width of the fine grid.

[0041] like Figure 5 As shown, in other embodiments, the height of the fine grid 400 in the thickness direction of the back-contact cell is less than the height of the first gridline 301 or the second gridline 302. Because the fine grid 400 utilizes a burn-through paste, the reduced height of the fine grid 400 also reduces the amount of silver paste required, thereby lowering production costs. Furthermore, the fine grid 400, hidden between the first gridline 301 and the second gridline 302, enhances the cell's appearance, making it neater and more aesthetically pleasing.

[0042] In some embodiments, the formation of the fine grid 400 can adopt a burn-through metal paste through screen printing, and the burn-through metal paste is printed on the surface of the battery cell to form a fine grid 400 line on the surface of the battery cell. The burn-through metal paste can be silver paste, aluminum paste, etc. Here, there is no restriction on the specific material of the burn-through metal paste. In actual use, technicians can choose a suitable material according to needs. The formation of the connecting grid line 300 can adopt a non-burn-through metal paste through screen printing, and the non-burn-through metal paste is printed on the surface of the battery cell to form the connecting grid line 300 on the surface of the battery cell. Here, there is no restriction on the specific material of the non-burn-through metal paste.

[0043] In some embodiments, the spacing between the first grid line 301 and the second grid line 302 is 0.01 mm to 0.2 mm. Furthermore, the width of the fine grid 400 is in the range of 0.02 mm to 0.1 mm. The width of the fine grid 400 is preferably smaller than the spacing between the first grid line 301 and the second grid line 302 to prevent damage to the first grid line 301 and the second grid line 302 caused by printing the fine grid 400. Preferably, the spacing between the first grid line 301 and the second grid line 302 is 0.2 mm, and the width of the fine grid 400 is 0.02 mm, thereby reducing the printing precision requirement for the fine grid 400 and improving the product yield.

[0044] The distance between the center of the pad point 100 and the edge 500 is 1 mm to 10 mm. Specifically, in such an embodiment, the distance between the center of the pad point 100 and the edge 500 of the back contact battery can be, for example, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 10 mm, or any value between 1 mm and 10 mm, without limitation. Placing the pad point 100 at a certain distance from the edge of the battery can avoid stress concentration at the edge of the battery, which is beneficial for improving the overall structural stability of the battery and extending its service life.

[0045] Furthermore, the distance between the centerline of the busbar 200 and the edge 500 of the back-contact cell is 0.1 mm to 0.5 mm. Specifically, in such an embodiment, the distance between the centerline of the busbar 200 and the edge 500 of the back-contact cell can be, for example, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or any value between 0.1 mm and 0.5 mm, without limitation. A closer distance between the busbar 200 and the cell edge means that the current has a shorter path during transmission, thereby reducing resistance losses and improving current transmission efficiency.

[0046] A solar cell includes the above-mentioned solar cell electrode structure. The technical effects of the solar cell are the same as those of the solar cell electrode structure, which will not be described in detail here.

[0047] A solar cell assembly includes the above-mentioned solar cell. Based on the above-mentioned solar cell, those skilled in the art know that a corresponding battery assembly can be obtained by combining multiple solar cells and / or other corresponding existing accessories.

[0048] In this embodiment, the multiple solar cells in the battery assembly can be connected in series in sequence to form a battery string, thereby realizing the series bus output of the current. For example, the series connection of the battery cells can be realized by providing welding strips (bus bars, interconnecting bars), conductive back plates, etc. It can be understood that in such an embodiment, the battery assembly may also include a metal frame, a back plate, photovoltaic glass and an adhesive film. The adhesive film can be filled between the front and back of the back contact battery and the photovoltaic glass, adjacent battery cells, etc. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the adhesive film can be EVA film or POE film. The specific selection can be made according to the actual situation and is not limited here.

[0049] Throughout this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" indicate 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.

[0050] 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: pad point; A main grid, which is arranged on a side of the back contact battery close to the edge; A connecting gate line, wherein one end of the connecting gate line is in electrical contact with the pad point, and the other end of the connecting gate line is in electrical contact with the main gate; A fine gate, wherein the fine gate is arranged in parallel with the connecting gate line, one end of the fine gate is in electrical contact with the pad point, and the other end of the fine gate is in electrical contact with the main gate; In which, the pad point, the main gate, the connecting gate line and the fine gate have the same properties, the connecting gate line includes at least a first gate line and a second gate line, the first gate line and the second gate line are arranged in parallel and spaced apart, the fine gate is arranged between the first gate line and the second gate line, the two ends of each of the first gate line and the second gate line are respectively connected to the pad point and the main gate, the ratio of the width of the first gate line to the width of the main gate is greater than or equal to 1 / 4 and less than or equal to 1 / 2, and / or the ratio of the width of the second gate line to the width of the main gate is greater than or equal to 1 / 4 and less than or equal to 1 / 2.

2. The electrode structure of the back contact battery according to claim 1, wherein: In the thickness direction of the back contact cell, the height of the fine grid is smaller than the height of the first grid line or the second grid line.

3. The electrode structure of the back contact battery according to claim 1, wherein: The center line of the fine grid passes through the center point of the pad point.

4. The electrode structure of the back contact battery according to claim 1, wherein: The first gate line and the second gate line have the same width.

5. The electrode structure of the back contact battery according to claim 1, wherein: The spacing distance between the first gate line and the second gate line is 0.01 mm-0.2 mm.

6. The electrode structure of the back contact battery according to claim 1, wherein: The width of the fine grid is in the range of 0.02 mm to 0.1 mm.

7. The electrode structure of the back contact battery according to claim 1, wherein: The width of the first gate line or the second gate line is greater than the width of the fine gate.

8. The electrode structure of the back contact battery according to claim 1, wherein: The distance between the center of the pad point and the edge is 1 mm to 10 mm.

9. The electrode structure of the back contact battery according to claim 1, wherein: The distance between the center line of the main grid and the edge is 0.1mm-0.5mm.

10. A back contact battery, characterized in that: The back contact cell comprises the electrode structure according to any one of claims 1 to 9.

11. A back contact battery assembly, characterized in that: The back-contact cell assembly comprises the back-contact cell of claim 10 .

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