Solar cell

Abstract

The utility model provides a solar cell, which comprises a substrate, a functional layer on the substrate and grid lines on the functional layer, the grid lines comprise fine grid lines, the fine grid lines comprise the following structures: basic grid lines, the basic grid lines are arc-shaped fine grid lines, a plurality of sections of basic grid lines are sequentially connected end to end to form grid line units, and the grid line units are arranged on the functional layer. The head ends and the tail ends of the basic grid lines are located on the same straight line, the top ends of the basic grid lines are also located on the same straight line, and the multiple rows of grid line units of the same structure are sequentially arranged to form thin grid lines. The top ends of the basic grid lines in one row of grid line units intersect at the head ends or the tail ends of the basic grid lines in the other row of grid line units. According to the utility model, the distribution uniformity of the grid lines is improved, the stress tolerance of the grid lines is stronger, the grid is not easy to break, and even if the grid is broken, only a very small area is influenced.

Description

Technical Field

[0001] The utility model mainly relates to the technical field of solar cells, in particular to a solar cell sheet. Background Art

[0002] Gridlines are metal conductors used to collect and transmit photogenerated current on solar cells. Gridlines consist of main gridlines and fine gridlines (also called auxiliary gridlines). The main gridlines are typically thicker and directly connect to the cell's external leads, while the fine gridlines are thinner and collect current and transmit it to the main gridlines. The gridline metallization process is a key step in the solar cell manufacturing process.

[0003] Traditional metallization methods include screen printing, which creates back-grid lines, back-field lines, and front-grid lines on the cell surface. Screen printing is a key process in solar cell manufacturing. It applies a conductive paste to the silicon wafer using a specific screen pattern, forming the cell's positive and negative electrodes. This process not only determines the cell's appearance but also directly impacts its photovoltaic conversion efficiency and cost.

[0004] Screen printing is currently the most mature and widely used metallization technology in the field of solar cells. It is a contact printing method. The slurry is squeezed by a scraper and adhered to the silicon wafer through the mesh. The pattern of the screen mesh determines the pattern of the electrode on the cell. At present, the most common electrode patterns on the front and back of the battery are grid-type. The fine grid lines and the main grid lines together divide the surface of the battery into several small rectangles. Because the grid lines block the incident light, the number and density of grid lines on the light-receiving side of the battery are smaller than those on the back. This is conducive to more light entering the battery, but it also brings a higher resistivity. The electroplating method can bring a variety of grid line electrode patterns, but its cost is relatively high and is still in the improvement stage. In short, the grid lines of the existing structural form are unevenly distributed, the carrier migration distance is relatively long, and the resistivity is also relatively high. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a solar cell sheet, which improves the uniformity of grid line distribution, has stronger stress tolerance and is less likely to cause grid breakage.

[0006] In order to solve the above technical problems, the present invention provides a solar cell, comprising a substrate, a functional layer on the substrate and a grid line located on the functional layer, the grid line comprising a fine grid line, and the fine grid line comprising the following structure: a basic grid line, the basic grid line being a segment of arc-shaped fine grid line; several segments of the basic grid lines are connected end to end in sequence to form a grid line unit, and the starting end and the tail end of each of the basic grid lines are on the same straight line, and the top end of each of the basic grid lines is also on the same straight line; multiple rows of the grid line units with the same structure are arranged in sequence to form the fine grid lines; for two adjacent rows of the grid line units, the top end of the basic grid line in one row of the grid line units intersects with the starting end or the tail end of the basic grid line in the other row of the grid line units.

[0007] Optionally, the basic grid line is a thin grid line in the shape of an arc.

[0008] Optionally, the basic grid line is a thin grid line in the shape of a semicircular arc.

[0009] Optionally, the basic grid lines are thin grid lines formed by two arcs in a Reuleaux triangle.

[0010] Optionally, a main grid line is further included, the main grid line is a straight line structure, and the intersection of the main grid line and the fine grid line is the intersection of the grid line units in two adjacent rows.

[0011] Optionally, the main grid lines are parallel to the straight line where the starting end and the tail end of each row of the basic grid lines are located.

[0012] Optionally, the main grid lines are perpendicular to the straight line where the starting end and the tail end of each row of the basic grid lines are located.

[0013] Optionally, the distances between two adjacent main grid lines are equal.

[0014] Optionally, the main grid lines and the thin grid lines are both made of aluminum or silver.

[0015] Optionally, a main grid line is further included, wherein the intersection of the main grid line and the fine grid line is the intersection of the grid line units in two adjacent rows, and each basic grid line and a section of the main grid line between the starting end and the tail end of the basic grid line form a Reuleaux triangle structure.

[0016] Compared with the prior art, the present invention has the following advantages: the fine grid lines in the battery include basic grid lines, which are arc-shaped thin grid lines. Several segments of basic grid lines are connected end to end in sequence to form grid line units, and the starting and tail ends of each basic grid line are on the same straight line, and the top ends of each basic grid line are also on the same straight line. Multiple rows of grid line units with the same structure are arranged in sequence to form fine grid lines. For two adjacent rows of grid line units, the top ends of the basic grid lines in one row of grid line units intersect with the starting or tail ends of the basic grid lines in the other row of grid line units, which can improve the uniformity of grid line distribution, and the grid lines have stronger stress tolerance and are less likely to break. Even if a break occurs, it only affects a very small area. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the present application. They are incorporated into and constitute a part of this application. The accompanying drawings illustrate embodiments of the present application and, together with this specification, serve to explain the principles of the present application. In the accompanying drawings:

[0018] Figure 1 This is a schematic structural diagram of a solar cell according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of the grid line in one embodiment of the utility model. Figure 1 ;

[0020] Figure 3 yes Figure 2 The middle part is an enlarged schematic diagram;

[0021] Figure 4 This is a schematic diagram of the structure of the grid line in one embodiment of the utility model. Figure 2 ;

[0022] Figure 5 This is a schematic diagram of the structure of the grid line in one embodiment of the utility model. Figure 3 ;

[0023] Figure 6 This is a schematic diagram of the structure of the grid line in another embodiment of the present invention. Figure 1 ;

[0024] Figure 7 yes Figure 6 The middle part is an enlarged schematic diagram;

[0025] Figure 8 This is a schematic diagram of the structure of the grid line in another embodiment of the present invention. Figure 2 ;

[0026] Figure 9 This is a schematic diagram of the structure of the grid line in another embodiment of the present invention. Figure 3 ;

[0027] Figure 10This is a schematic diagram of the structure of the grid line in another embodiment of the present invention. Figure 4 .

[0028] In the picture:

[0029] 100-base;

[0030] 200-functional layer;

[0031] 300-grid line, 310-fine grid line, 320-main grid line;

[0032] 311 - basic gate line, 312 - gate line unit. DETAILED DESCRIPTION

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0034] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0035] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside" and "outside" refer to the components themselves.

[0036] refer to Figures 1 to 5As shown, the solar cell of this embodiment includes a substrate 100, a functional layer 200 on the substrate 100, and a grid line 300. The grid line 300 includes a fine grid line 310, and the fine grid line 310 includes the following structure: a basic grid line 311, the basic grid line 311 is a segment of arc-shaped fine grid line, and several segments of basic grid lines 311 are connected end to end in sequence to form a grid line unit 312, and the beginning and end of each basic grid line 311 are on the same straight line, and the top of each basic grid line 311 is also on the same straight line. Multiple rows of grid line units 312 with the same structure are arranged in sequence to form the fine grid line 310, and for two adjacent rows of grid line units 312, the top of the basic grid line 311 in one row of grid line units 312 intersects with the beginning or end of the basic grid line 311 in another row of grid line units 312. Generally speaking, the functional layer 200 of the battery may include a doped conductive layer, a dielectric layer, etc., which will not be repeated here.

[0037] Solar cells rely on fine grid lines 310 and main grid lines 320 to collect carriers. However, the spacing between the main grid lines 320 is very large, often several dozen times the spacing between the fine grid lines 310. If a grid line 310 or a main grid line 320 is broken, carrier transmission losses will increase. This embodiment reduces the impact of grid breakage by designing a curved grid line network.

[0038] In this embodiment, the fine gate lines 310 are mainly based on the basic gate lines 311 and are arranged in an orderly manner to form a network structure. Figure 3 As shown, the smallest part of the fine grid line 310, that is, the basic grid line 311 is at A marked by the dotted box in the figure. It can be seen that the basic grid line 311 is an arc-shaped grid line, and its left and right sides are both basic grid lines 311 with the same structure. In this row of grid line structure, the starting end (such as the left side) of each basic grid line 311 is connected to the tail end (such as the right side) of the previous basic grid line 311, and the tail end (on the right side) of each basic grid line 311 is connected to the starting end (on the left side) of the next basic grid line 311. In this way, a grid line unit 312 is formed by connecting several basic grid lines 311 in sequence. The grid line unit 312 can refer to Figure 2 The part marked by the dotted box.

[0039] In addition, the beginning and the end of each basic grid line 311 are on the same straight line, and the top of each basic grid line 311 is also on the same straight line. Figure 3As shown, the basic gate line 311 at A and the basic gate line 311 at B in the figure are used as examples for explanation, which are referred to as base A and base B respectively. In the figure, the starting end and the tail end of base A are both located on the straight line L2, and the starting end and the tail end of base B are also located on the straight line L2, that is, the starting end and the tail end of all the basic gate lines 311 in the row are both located on the straight line L2. The top of base A and the top of base B are also on the straight line L1, and it can be seen that the height of the basic gate line 311 in each gate line unit 312 is the same. Based on this structure, it is guaranteed that when multiple rows of gate line units 312 with the same structure are arranged in sequence to form fine gate lines 310, the top of the basic gate line 311 in one row of gate line units 312 of two adjacent rows can intersect with the starting end or the tail end of the basic gate line 311 in another row of gate line units 312. For example, again taking Figure 3 For example, for the first row of gridline units 312 (denoted by R1) and the second row of gridline units 312 (denoted by R2), it can be seen from the figure that the beginning / end of R1 is located at the bottom of the row, while the top of R2 is located at the top of the row and intersects with the beginning / end of R1. Therefore, each basic gridline 311 and each gridline unit 312 are interconnected, ultimately forming a fine gridline 310 that covers the entire solar cell.

[0040] This embodiment uses a curved fine grid line network structure to form multiple connection points, making the grid lines more resistant to stress and less prone to grid breakage. In addition, this multi-transmission path structure means that even if a grid break occurs, it only affects a small area, providing more transmission paths to choose from.

[0041] In one example, the basic gate line 311 is a thin gate line 310 in the shape of a circular arc. Further, the basic gate line 311 is a thin gate line 310 in the shape of a semicircular arc.

[0042] In one example, the gate lines further include a main gate line 320, which is a straight line structure, and the intersection of the main gate line 320 and the fine gate line 310 is the intersection of two adjacent rows of gate line units 312. Furthermore, the main gate line 320 is parallel to the straight line where the starting and ending ends of each row of basic gate lines 311 are located, or the main gate line 320 is perpendicular to the straight line where the starting and ending ends of each row of basic gate lines 311 are located.

[0043] refer to Figure 4 As shown in the figure, the straight line where the starting and ending ends of each row of basic grid lines 311 are located is L3. Of course, although the straight lines where the starting and ending ends of basic grid lines 311 in other rows are located are not L3, they are parallel to L3. Therefore, this embodiment only uses L3 as an example for explanation and does not affect the essence of this embodiment. In this embodiment, the main grid line 320 can be set to be parallel to L3. Figure 5As shown in the figure, the straight line where the starting and ending ends of each row of basic grid lines 311 are located is still L3. In this embodiment, the main grid lines 320 can also be set parallel to L3. Compared with the case where the main grid lines 320 are neither parallel nor perpendicular to L3, the above two ways of setting the main grid lines 320 make the grid line structure more stable and the battery conversion efficiency better.

[0044] In one example, the distances between two adjacent main grid lines 320 are equal. When the distances between the main grid lines 320 are equal, current can be collected more evenly from the surface of the solar cell, reducing the uneven distribution of current on the surface of the cell and reducing power loss. In addition, equal spacing between the main grid lines 320 makes it easier to achieve automated printing, which helps to improve production efficiency and battery consistency. Evenly distributed main grid lines 320 can reduce local overheating or material fatigue caused by current concentration, helping to reduce battery performance degradation during long-term use.

[0045] In one example, the main grid lines 320 and the fine grid lines 310 are both made of aluminum or silver. During the manufacturing process of solar cells, the choice of grid line material has a significant impact on the performance and cost of the cell. For aluminum grid lines, aluminum is a relatively low-cost metal and is typically used on the back of the cell to form an aluminum back field. The main advantages of aluminum grid lines are their low cost and good conductivity. For silver grid lines, silver has extremely high conductivity and the best conductivity of all metals. On the front of the solar cell, the silver grid lines can effectively collect current and reduce power loss. However, the cost of silver is relatively high, which means that when it is used in large-scale production, it will increase the cost of the cell.

[0046] The solar cell of this embodiment has a fine grid line 310 including a basic grid line 311, which is a segment of an arc-shaped fine grid line. Several segments of the basic grid lines 311 are connected end to end in sequence to form a grid line unit 312, and the starting and tail ends of each basic grid line 311 are on the same straight line, and the top of each basic grid line 311 is also on the same straight line. Multiple rows of grid line units 312 with the same structure are arranged in sequence to form the fine grid line 310. For two adjacent rows of grid line units 312, the top of the basic grid line 311 in one row of grid line units 312 intersects with the starting or tail end of the basic grid line 311 in the other row of grid line units 312, and the basic grid line 311 is a segment of an arc-shaped fine grid line, which can improve the uniformity of the grid line distribution, and the grid line stress tolerance is stronger, and it is not easy to break. Even if a break occurs, it only affects a very small area.

[0047] refer to Figures 6 to 10As shown, another embodiment of the present invention is a solar cell, whose structure includes a substrate 100, a functional layer 200 on the substrate 100 and a grid line 300. The grid line 300 includes a fine grid line 310, and the fine grid line 310 includes the following structure: a basic grid line 311, the basic grid line 311 is a segment of arc-shaped fine grid line, and a plurality of segments of basic grid lines 311 are connected end to end in sequence to form a grid line unit 312, and the beginning and end of each basic grid line 311 are on the same straight line, and the top of each basic grid line 311 is also on the same straight line. Multiple rows of grid line units 312 with the same structure are arranged in sequence to form the fine grid line 310, and for two adjacent rows of grid line units 312, the top of the basic grid line 311 in one row of grid line units 312 intersects with the beginning or end of the basic grid line 311 in the other row of grid line units 312, wherein the basic grid line 311 is a fine grid line 310 composed of two arc segments in a Reuleaux triangle.

[0048] refer to Figure 7 As shown, the basic grid line 311 shown by the dotted line in the figure is a thin grid line 310 composed of two arc segments, which is different from the arc-shaped basic grid line 311. The Reuleaux triangle is a special geometric shape, which is composed of three arc segments drawn with the vertex of an equilateral triangle as the center and the side length as the radius. This shape has the same width no matter from which direction it is viewed, so it is an equal-width curve, and the width of the Reuleaux triangle is equal to the side length of the equilateral triangle that constructs it. This embodiment utilizes the minimum area property of the Reuleaux triangle, that is, the Reuleaux triangle is the shape with the smallest area among all equal-width curves.

[0049] In one example, the gate lines further include a main gate line 320 , which is a straight line structure, and an intersection point between the main gate line 320 and the fine gate line 310 is an intersection point between gate line units 312 in two adjacent rows.

[0050] In one example, the main grid line 320 is parallel to the straight line where the beginning and the end of each row of basic grid lines 311 are located. Figure 8 shown.

[0051] In one example, the main grid line 320 is perpendicular to the straight line where the beginning and the end of each row of basic grid lines 311 are located. Figure 9 shown.

[0052] In one example, the distances between two adjacent bus bars 320 are equal.

[0053] In one example, the main grid lines 320 and the fine grid lines 310 are both made of aluminum or silver.

[0054] In one example, the gate line also includes a main gate line 320, the intersection of the main gate line 320 and the fine gate line 310 is the intersection of two adjacent rows of gate line units 312, and each basic gate line 311 and a section of the main gate line 320 between the starting end and the tail end of the basic gate line 311 form a Reuleaux triangle structure.

[0055] refer to Figure 10 As shown in the figure, the main grid line 320 is not a straight line, but is composed of various arc-shaped segments. For the row of grid line units 312 having the main grid line 320, each basic grid line 311 has a segment of the main grid line 320 at its beginning and end, and these segmented main grid lines 320 are combined together to form a complete main grid line 320. In addition, each basic grid line 311 and a segment of the main grid line 320 between the beginning and end of the basic grid line 311 form a Reuleaux triangle structure. In other words, the overall structure of the grid lines (including the main grid lines 320 and the fine grid lines 310) in this embodiment is equivalent to an array or network formed by a Reuleaux triangle structure.

[0056] For other details of the components, parts, or devices in this embodiment that are the same as those in the previous embodiment, reference can be made to the previous embodiment and will not be elaborated here. For example, the main grid line 320 is parallel to L3 or perpendicular to L3, and both cases are applicable, whether the basic grid line 311 is an arc or two arcs in a Reuleaux triangle.

[0057] When applying the grid lines of this embodiment, the grid lines on the front (light-receiving) side of the battery can be set to a grid line structure based on arcs as the basic grid lines 311, and the main grid lines 320 are arranged equidistantly at the intersections of the fine grid lines 311. The grid lines on the back side of the battery are a grid line structure based on two arcs in a Reuleaux triangle as the basic grid lines 311, but with a smaller area and higher density, and the main grid lines 320 are also arranged equidistantly at the intersections of the fine grid lines 311.

[0058] The solar cell of this embodiment has a fine grid line 310 including a basic grid line 311, which is a segment of arc-shaped fine grid line. Several segments of basic grid lines 311 are connected end to end in sequence to form grid line units 312, and the starting and tail ends of each basic grid line 311 are on the same straight line, and the top of each basic grid line 311 is also on the same straight line. Multiple rows of grid line units 312 with the same structure are arranged in sequence to form fine grid lines 310. For two adjacent rows of grid line units 312, the top of the basic grid line 311 in one row of grid line units 312 intersects with the starting or tail end of the basic grid line 311 in the other row of grid line units 312, and the basic grid line 311 is a fine grid line 310 composed of two arc segments in a Reuleaux triangle, which can improve the uniformity of grid line distribution, make the grid line more resistant to stress, and not easily break. Even if a break occurs, it only affects a very small area.

[0059] The basic concepts have been described above. It will be apparent to those skilled in the art that the above utility model disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to this application. Such modifications, improvements, and amendments are suggested in this application and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0060] Similarly, it should be noted that, in order to simplify the description of the present disclosure and thus facilitate understanding of one or more utility model embodiments, the foregoing description of the present embodiment sometimes combines multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of the present application requires more features than those recited in the claims. In fact, the features of an embodiment may be fewer than the total features of a single embodiment disclosed above.

[0061] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions can be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A solar cell comprising a substrate, a functional layer on the substrate, and a grid line on the functional layer, characterized in that: The gate lines include thin gate lines, and the thin gate lines include the following structure: A basic grid line, wherein the basic grid line is a segment of an arc-shaped thin grid line; a plurality of segments of the basic grid lines are sequentially connected end to end to form a grid line unit, and the starting and tail ends of each of the basic grid lines are on the same straight line, and the top ends of each of the basic grid lines are also on the same straight line; Multiple rows of the gate line units with the same structure are arranged in sequence to form the fine gate lines; for two adjacent rows of the gate line units, the top ends of the basic gate lines in one row of the gate line units intersect with the beginning or end of the basic gate lines in the other row of the gate line units.

2. The solar cell according to claim 1, wherein: The basic grid line is a thin grid line in an arc shape.

3. The solar cell according to claim 2, wherein: The basic grid line is a thin grid line in the shape of a semicircle.

4. The solar cell according to claim 1, wherein: The basic grid lines are thin grid lines formed by two circular arcs in a Reuleaux triangle.

5. The solar cell according to any one of claims 2 to 4, wherein: It also includes a main grid line, which is a straight line structure, and the intersection of the main grid line and the fine grid line is the intersection of the grid line units in two adjacent rows.

6. The solar cell according to claim 5, wherein: The main grid lines are parallel to the straight line where the starting end and the tail end of each row of the basic grid lines are located.

7. The solar cell according to claim 5, wherein: The main grid lines are perpendicular to the straight line where the starting and tail ends of each row of the basic grid lines are located.

8. The solar cell according to claim 5, wherein: The distance between two adjacent main grid lines is equal.

9. The solar cell according to claim 5, wherein: The main grid lines and the thin grid lines are made of aluminum or silver.

10. The solar cell according to claim 4, wherein: It also includes a main grid line, the intersection of the main grid line and the fine grid line is the intersection of the grid line units in two adjacent rows, and each basic grid line and a section of the main grid line between the starting end and the tail end of the basic grid line form a Reuleaux triangle structure.

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