Solar cell sheet, battery string, and method for manufacturing both.

Abstract

The present invention provides a solar cell sheet, a battery string, and a method for manufacturing both. At least one surface of the solar cell sheet comprises a plurality of first grid line structures and a second grid line structure located on the plurality of first grid line structures, and at least a part of the area of ​​at least one second grid line structure does not contact the reaction layer of the solar cell sheet. The plurality of second grid line structures are adapted to contact the connection structure between the plurality of battery sheets. The solar cell sheet of the present invention can reduce the contact between the main grid and the reaction layer, strengthen the connection between the connection structure between the battery sheets and the main grid, and improve the efficiency, stability and reliability of the solar cell.

Description

Technical Field

[0001] The present invention mainly relates to the field of solar cells, and particularly relates to solar cell sheets, cell strings, and manufacturing methods thereof.

Background Art

[0002] The grid line structure of existing solar cell sheets usually has a main grid as a grid line containing a silver component, and in some cases, the fine grid is a grid line containing an aluminum component (for example, the fine grid on the back of a P-type perc cell contains aluminum). In the actual production process, by printing the main grid line first and then the fine grid line, overlapping the main grid line and the fine grid line to form a lap joint is the mainstream printing method. When assembling and welding, a silver-tin alloy is formed at the welding point between the main grid line and the welding band (or the connection structure between other cell sheets) to obtain the effects of connection and conduction. In this welding method, the current converges from the fine grid to the main grid and flows out through the welding band. However, this method of non-linearly leading out the current causes a large resistance loss and reduces the module power. At the same time, due to process limitations, there is also a large height difference between the main grid and the fine grid. The height of the fine grid is significantly higher than that of the main grid, and hollow welding is likely to occur between the welding band and the main grid, causing welding defects. In addition, in existing solar energy cell sheets, the main grid and the reaction layer directly contact each other, causing damage to the reaction layer and reducing the efficiency.

Summary of the Invention

Means for Solving the Problems

[0003] The technical problem that this invention aims to solve is to provide a solar cell sheet, a battery string, and a method for manufacturing both, which can improve the efficiency of a solar cell and the stability and reliability of a solar cell by reducing contact between the main grid and the reaction layer and improving the connection between the main grid and the battery sheet connection structure.

[0004] To solve the above technical problems, the present invention provides a solar cell sheet wherein at least one surface of the solar cell sheet comprises a plurality of first grid line structures and a plurality of second grid line structures located on the plurality of the first grid line structures, and at least a portion of the region of at least one of the second grid line structures does not contact the reaction layer of the solar cell sheet, and the plurality of second grid line structures are applied to contact the connection structure between the plurality of solar cell sheets.

[0005] Alternatively, in one embodiment of the present invention, the plurality of second grid line structures comprises a plurality of arc-type structures and / or multi-stage arc-type structures.

[0006] Alternatively, in one embodiment of the present invention, the plurality of second grid line structures comprises a plurality of linear structures and / or multi-stage linear structures.

[0007] Alternatively, in one embodiment of the present invention, the first grid line structure also comprises a linear structure, wherein the plurality of first grid line structures include a plurality of first grid lines extending along a first direction and arranged along a second direction, and the plurality of second grid line structures include a plurality of second grid lines extending along a first direction and arranged along a second direction, and / or extending along a second direction and arranged along a first direction, wherein the plurality of second grid lines are located on at least some of the plurality of first grid lines, and the connecting structure is a welding band or welding paste in contact with the plurality of second grid lines.

[0008] Alternatively, in one embodiment of the present invention, a plurality of second grid lines extend only in a first direction and are arranged in a second direction, and the first grid line structure further includes a plurality of third grid lines that extend in a second direction and are arranged in a first direction, the plurality of second grid lines straddle the plurality of third grid lines, and the third grid lines are made of the same material as the first grid lines.

[0009] Alternatively, in one embodiment of the present invention, the second grid line structure further includes a plurality of fourth grid lines extending along a second direction and arranged along a first direction, wherein the plurality of fourth grid lines are located on at least some of the third grid lines, the plurality of second grid lines span the plurality of third grid lines and the plurality of fourth grid lines, and the fourth grid lines are made of the same material as the second grid lines.

[0010] Alternatively, in one embodiment of the present invention, a plurality of second grid lines in the solar cell sheet extend only in a second direction and are arranged along a first direction, and the first grid line structure further includes a plurality of third grid lines that extend along a second direction and are arranged along a first direction, wherein the plurality of second grid lines are located on at least some of the third grid lines, and the third grid lines are made of the same material as the first grid lines.

[0011] Alternatively, in one embodiment of the present invention, the arrangement in which a plurality of second grid lines are located on at least some of a plurality of first grid lines is such that the second grid lines partially or completely surround the first grid lines.

[0012] Alternatively, in one embodiment of the present invention, a connecting layer is further provided located between the first grid line structure and the second grid line structure.

[0013] Alternatively, in one embodiment of the present invention, the connecting layer consists of at least one of an inorganic material, an organic material, and a metal.

[0014] Alternatively, in one embodiment of the present invention, a boundary layer is formed at the contact surface between the first grid line structure and the second grid line structure by component penetration, and the boundary layer includes a portion of the first grid line structure and / or a portion of the second grid line structure.

[0015] Alternatively, in one embodiment of the present invention, the first grid line structure contained in the boundary layer accounts for 1% to 99% of the first grid line structure before the component penetration occurs, and the second grid line structure contained in the boundary layer accounts for 1% to 99% of the second grid line structure before the component penetration occurs.

[0016] The present invention further provides a method for manufacturing a solar cell sheet, which is applied to the manufacture of a solar cell sheet and comprises the steps of printing a plurality of first grid line structures on at least one surface of a solar cell sheet, and printing a plurality of second grid line structures on the surface, wherein the plurality of second grid line structures are located on the plurality of first grid line structures, and at least a portion of the area of ​​at least one second grid line structure does not come into contact with the reaction layer of the solar cell sheet, wherein the plurality of second grid line structures are applied to come into contact with the connection structures between a plurality of battery seals.

[0017] The present invention further provides a solar cell string, which includes the solar cell sheets described in any of the embodiments described above, and which forms a solar cell string by sequentially connecting two adjacent solar cell sheets using a connection structure.

[0018] The present invention further provides a method for manufacturing a solar cell string, comprising the steps of: providing a plurality of battery sheets, each battery sheet including a positive electrode surface and a negative electrode surface, having a plurality of first grid line structures and a plurality of second grid line structures on the positive electrode surface and / or the negative electrode surface, wherein the plurality of second grid line structures are located on the plurality of first grid line structures, and at least a portion of the region of at least one second grid line structure does not come into contact with the reaction layer of the solar cell sheet; and sequentially connecting the positive electrode surface and the negative electrode surface of each battery sheet with a plurality of connecting structures to connect the plurality of battery sheets in series, wherein the connecting structures come into contact with the second grid line structures on the positive electrode surface and / or the negative electrode surface.

[0019] Compared to conventional technology, the solar cell sheet and battery string of the present invention avoid hollow welding due to insufficient height of the main group by printing the main group onto a fine grid and then directly welding the main group to the welding band. The technical considerations of the present invention effectively reduce contact between the main grid and the reaction layer, strengthen the connection between the main grid and the welding band, improve the current efficiency of the battery sheet, and extend the service life of the solar cell sheet. [Brief explanation of the drawing]

[0020] The accompanying drawings are included to provide a further understanding of the present application, and are described to constitute part of the present application. The accompanying drawings illustrate embodiments of the present application and, together with this specification, serve to illustrate the principles of the present application. In the drawing, [Figure 1A] Figure 1A is a schematic diagram of a conventional solar cell sheet viewed from the front in a plan view. [Figure 1B] Figure 1B is a front cross-sectional view of the solar cell sheet shown in Figure 1A. [Figure 1C] Figure 1C is a schematic diagram of a conventional solar cell sheet viewed from the back surface in a plan view. [Figure 1D] Figure 1D is a cross-sectional view of the back surface of the solar cell sheet shown in Figure 1C. [Figure 2A] Figure 2A is a schematic plan view of a solar cell sheet according to Embodiment 1 of the present invention, as viewed from the front. [Figure 2B] Figure 2B is a cross-sectional view of the solar cell sheet shown in Figure 2A. [Figure 3A] Figure 3A is a schematic plan view of a solar cell sheet according to Embodiment 2 of the present invention, as viewed from the front. [Figure 3B] Figure 3B is a cross-sectional view of the solar cell sheet shown in Figure 3A. [Figure 4A] Figure 4A is a schematic plan view of a solar cell sheet according to Embodiment 3 of the present invention, as viewed from the front. [Figure 4B] Figure 4B is a cross-sectional view of the solar cell sheet shown in Figure 4A. [Figure 5] Figure 5 is a schematic plan view of a solar cell sheet according to Embodiment 4 of the present invention, as viewed from the front. [Figure 6] Figure 6 is a cross-sectional view of a solar cell sheet according to Embodiment 5 of the present invention. [Figure 7] Figure 7 is a schematic diagram showing the flow of a method for manufacturing a solar cell sheet according to an embodiment of the present invention. [Figure 8] Figure 8 is a schematic diagram showing the flow of a method for manufacturing a solar cell string according to an embodiment of the present invention. [Figure 9A] Figure 9a is a cross-sectional view of a solar cell sheet having a connection layer or a boundary layer according to an embodiment of the present invention. [Figure 9B] Figure 9b is a cross-sectional view of a solar cell sheet having a connection layer or a boundary layer according to an embodiment of the present invention. [Figure 9C] Figure 9c is a cross-sectional view of a solar cell sheet having a connection layer or a boundary layer according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0021] To more clearly illustrate the technical considerations of the embodiments of this application, the drawings necessary for describing the embodiments are briefly described below. Clearly, the drawings in the following description are only a few examples or embodiments of this application, and a person skilled in the art could apply this application to other similar scenarios based on these drawings without expending any effort to demonstrate inventiveness. Unless otherwise stated or as is evident from the language context, the same reference numerals in the figures represent the same structure or operation.

[0022] As set forth in this application and claims, unless the context explicitly suggests an exception, terms such as “one,” “a kind,” and / or “it” do not specifically refer to a singular number and may include plurals. Generally, the terms “equipment” and “includes” only indicate the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list; the method or apparatus may include other steps or elements.

[0023] Unless otherwise specified, the relative arrangement of components and steps, numerical expressions, and numerical values ​​described in these embodiments do not limit the scope of this application. At the same time, it should be understood that the dimensions of each part shown in the drawings are not depicted in actual proportional relationships for the sake of clarity. While detailed discussion of art, methods, and apparatus known to those skilled in the art may not be provided, where appropriate, such art, methods, and apparatus shall be considered part of the patented specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as illustrative only and not as limitations. Accordingly, other examples of the exemplary embodiments may have different values. It should be noted that in the following drawings, similar reference numerals and letters indicate similar items. Thus, if an item is defined in one drawing, it does not need to be discussed further in subsequent drawings.

[0024] In the specification of this application, it should be understood that the orientations or positional relationships indicated by directional terms such as "front, back, top, bottom, left, right," "lateral, vertical, vertical, horizontal," and "top, bottom" are generally based on the orientations or positional relationships shown in the drawings and are used solely to facilitate and simplify the explanation of this application. Unless otherwise stated, these directional terms do not indicate or imply that the specified device or element has a particular orientation, or must be configured and operate in a particular orientation, and therefore should not be understood as limiting the scope of protection of this application. The directional terms "inside" and "outside" refer to the inside and outside of the contour of each part itself.

[0025] For the sake of clarity, the spatial relationship between one part or feature shown in a drawing and another part or feature may be described here using spatial relational terms such as "above," "above," "on the top surface," or "on the top surface." It will be understood that spatial relative terms are intended to include directions other than those shown in the drawing for parts in use or operation. For example, if a part in the drawing is reversed, a part described as "above another part or structure" or "on top of another part or structure" would be positioned as "below another part or structure" or "below another part or structure." Thus, the exemplary term "above" could include two orientations: "above" and "below." The part may also be positioned in other different ways (by rotating 90 degrees or in other orientations), and the spatial relative terms used herein may be appropriately explained.

[0026] Furthermore, it is necessary to explain that the use of terms such as "first," "second," etc., to limit parts is simply to make it easier to distinguish corresponding parts, and unless otherwise stated, these terms have no special meaning and should not be understood as limitations on the scope of protection of this application. In addition, while the terms used in this application are selected from publicly known terms, some terms in the specification of this application were selected at the applicant's own discretion, and their detailed meanings are explained in the relevant parts of this specification. Moreover, it is necessary to understand this application not only in terms used, but also in the meanings contained within each term.

[0027] When a component is referred to as “on another component,” “connected to another component,” “coupled to another component,” or “in contact with another component,” it should be understood that it may be directly on, connected to, coupled to, or in contact with the other component, or an inserted component may be present. In contrast, when a component is referred to as “directly on another component,” “directly connected,” “directly coupled,” or “directly in contact,” no inserted component is present. Similarly, when a component is referred to as “electrically in contact with” or “electrically coupled” to another component, there is an electrical path between the first component and the second component that can conduct current. This electrical path may include a capacitor, a coupled inductor, and / or other components that can conduct current, and furthermore, the conductive members do not have to be in direct contact with each other.

[0028] In this application, flowcharts are used to illustrate the operations performed by the systems according to the embodiments of this specification. It should be understood that the operations described above or below are not necessarily performed exactly in order. Conversely, various steps can be processed in reverse order or simultaneously. It is also possible to add other operations to these flows or remove one or more steps from these flows.

[0029] Figure 1A is a schematic diagram of a conventional solar cell sheet 100 viewed from the front in plan view. Figure 1B is a cross-sectional view of the front of the solar cell sheet 100 shown in Figure 1A. Figure 1C is a schematic diagram of the solar cell sheet 100 viewed from the back in plan view. Figure 1D is a cross-sectional view of the back of the solar cell sheet 100 shown in Figure 1C. Since the present invention relates to a multilayer grid line structure in a solar cell sheet, the plan views in the accompanying drawings of the present invention merely illustrate the arrangement structure of grid lines on the surface of the solar cell and differ somewhat from the concept of a plan view in the general sense. It is understood that the vertical positional relationships between the multilayer grid line structures must be fully and thoroughly understood by combining each cross-sectional view with the textual explanations.

[0030] As shown with reference to Figures 1A to 1D, the grid line arrangement on the front of a conventional solar cell sheet 100 involves directly printing a silver-containing main grid 11 onto a reaction layer 20 covering the surface of a silicon wafer 10, and then welding a connecting structure 40 (e.g., a welding band) onto the main grid 11. While the configurations shown in Figures 1(A) to 1(D) facilitate printing, the main grid 11 and the reaction layer 20 come into direct contact (the area enclosed by the dashed line in Figure 1B), damaging the reaction layer 20 and reducing battery efficiency. Furthermore, as can be seen particularly in Figure 1D, on the back surface of the solar cell sheet 100, the height of the main grid 11 is lower than that of the fine grid 12, making it difficult to connect the connecting structure 40 to the main grid 11, increasing the likelihood of hollow welding, and affecting battery efficiency. As a result, existing solar cells have a slight defect in their structure where the fine gates are located above the main gate.

[0031] Furthermore, the reaction layer 20 shown in Figures 1A to 1D and proposed below in relation to various embodiments of the present invention may be any single or multilayer layer in or on the battery sheet or on the battery surface, playing roles such as PN junction, electrical conductivity, passivation, reflection reduction and / or other protection, electron generation, and electrical conductivity.

[0032] The present invention provides a type of solar cell sheet in which one side of the solar cell sheet comprises a plurality of first grid line structures and a plurality of second grid line structures located on the plurality of first grid line structures, and at least a portion of at least one of the second grid line structures is not in contact with the reaction layer of the solar cell sheet. In this case, the plurality of second grid line structures are applied so as to be in contact with the connection structures between the plurality of cell sheets. Such a structure can effectively reduce contact between the main grid and the reaction layer, strengthen the connection between the main grid and the weld band to improve efficiency, and improve the stability and reliability of the solar cell.

[0033] It should be noted that the present invention does not specify the type of battery. Therefore, in different embodiments of the present invention, the solar cell may have two opposing surfaces or only one surface (for example, a back-junction battery IBC). When the solar cell has two opposing surfaces, one of the two surfaces may be provided with the first grid line structure and the second grid line structure detailed below. On the other hand, when the solar cell has only one surface and the positive and negative electrodes of the battery are simultaneously on that surface, in such embodiments, both the first grid line structure and the second grid line structure are on that single surface. Furthermore, the present invention is not limited to the shapes of the first grid line structure and the second grid line structure described above. Specifically, in some embodiments of the present invention, the plurality of second grid line structures include a plurality of arc-shaped structures and / or multi-stage arc-shaped structures. In another embodiment of the present invention, the plurality of second grid line structures include a plurality of linear structures and / or multi-stage linear structures. Furthermore, the second grid line structure on the solar cell sheet of the present invention may consist only of a plurality of arc-type structures and / or multi-stage arc-type structures, or only of a plurality of linear structures and / or multi-stage linear structures, or may include a plurality of arc-type structures and / or multi-stage arc-type structures and a plurality of linear structures and / or multi-stage linear structures simultaneously, and the specific combination thereof is not specifically limited in this application.

[0034] Example 1 Figure 2A is a schematic diagram of the grid line arrangement of a solar cell sheet 200 according to Embodiment 1 of the present invention. Figure 2B is a cross-sectional view of the solar cell sheet 200 shown in Figure 2A.

[0035] In the embodiment shown in Figures 2A and 2B, the first grid line structure 31 and the second grid line structure 32 are linear structures, and in this embodiment, referring to the coordinate axes shown in Figure 2A, the X-axis direction is the first direction and the Y-axis direction is the second direction. Note that the first direction X and the second direction Y mentioned above merely exemplify the relative positions of the arrangement of the first grid line 31 and the second grid line 32, and do not necessarily indicate that they are orthogonal to each other. Furthermore, Figures 2A and 2B show either one surface of the solar cell 200, and for example, in the case of a double-sided cell, this surface may be its front or back. Alternatively, in the case of a single-sided cell, Figures 2A and 2B show this single side.

[0036] According to Figures 2A and 2B, one surface of the solar cell sheet 200 includes a plurality of first grid lines 31 extending in a first direction X and arranged in a second direction Y, a plurality of second grid lines 32 extending in the first direction X and arranged in the second direction Y and located on the plurality of first grid lines 31, and a connecting structure (specifically, a welding band) 40 that straddles the plurality of first grid lines 31 and contacts the plurality of second grid lines 32 (specifically, it may be welded onto the second grid line structure 32).

[0037] For example, in the embodiments shown in Figures 2A and 2B, the components of the second grid line 32 include silver (similar to the main grid in conventional manufacturing methods). On the other hand, the first grid line 31 can be similar to the fine grid in conventional manufacturing methods, and in some embodiments of the present invention, the first grid line includes silver and may be, for example, the fine grid line on the back surface of a P-type perc battery. Although such examples are given, it should be understood that the present invention does not impose specific restrictions on the materials of the first and second grid lines. As can be seen from Figure 2(A), the solar cell sheet 200 is thought to employ a main grid pad structure in which the second grid line 32 (main grid) is abstracted as a pad point and plays a role in connecting to the connection structure 40 (e.g., a welding band).

[0038] Specifically, in order to position multiple second grid lines 32 on at least some of multiple first grid lines 31, the printing process involves first printing the first grid lines 31 (fine grids) on the reaction layer 20 covering the silicon wafer 10, and then printing the second grid lines 32 (main grids) so that the second grid lines 32 are positioned on top of the first grid lines 31. This configuration effectively reduces contact between the second grid lines 32 and the reaction layer 20, thereby reducing losses in the reaction layer 20 and improving battery efficiency.

[0039] In the embodiments shown in Figures 2A to 2B, a second grid line 32 is provided on each first grid line 31, but this configuration is not given as an example in the present invention. Exemplarily, in some other embodiments, multiple second grid lines 32 are located on only a portion of multiple first grid lines 31. For example, in some embodiments, the second grid lines 32 are located on only a portion of the first grid lines 31, and there are also first grid lines 31 on which no second grid lines 32 are provided.

[0040] As shown in Figures 2A and 2B, it is understood that a preferred embodiment of the present invention is shown in which the length of the second grid line 32 is shorter than the length of the first grid line 31, that is, the second grid line 32 is discretely arranged on the first grid line 31. This setting reduces the amount of silver consumed in the second grid line compared to a continuously installed method, enabling further cost reduction. Also, as shown in Figure 2(A), the width of the second grid line 32 is slightly larger than the width of the first grid line 31, and the length of the second grid line 32 is also longer than the width of the connection structure 40, thereby ensuring the current concentration effect of the first grid line 31, improving the welding efficiency between the second grid line 32 and the connection structure 40, and improving the stability of the battery.

[0041] Example 2 Figure 3A is a schematic diagram of the grid line arrangement of a solar cell sheet 300 according to Embodiment 2 of the present invention. Figure 3B is a cross-sectional view of the solar cell sheet 300 shown in Figure 3A. Embodiment 2 is a further modification based on Embodiment 1. Similar to Embodiment 1 described above, in this embodiment as well, a first direction X and a second direction Y are set, and Figures 3(A) and 3(B) show either one of the surfaces of the solar cell 300.

[0042] In the embodiments shown in Figures 3A to 3B, the plurality of second grid lines 32 in the solar cell sheet extend only along the first direction X and are arranged along the second direction Y, and the first grid line structure in the solar cell sheet 300 further includes a plurality of third grid lines 33 that extend along the second direction Y and are arranged along the first direction X, and the plurality of second grid lines 32 straddle the plurality of third grid lines 33 which are made of the same material as the first grid lines 31.

[0043] As shown in Figure 3A, the solar cell sheet 300 in this embodiment is provided with a plurality of first grid lines 31 extending along a first direction X and arranged along a second direction Y, a plurality of second grid lines 32 extending along a first direction X and arranged along a second direction Y, and a plurality of third grid lines 33 extending along a second direction Y and arranged along a first direction X. In this embodiment, the material of the third grid lines 33 is the same as that of the first grid lines 31 (or can be understood as a similarly fine grid).

[0044] Specifically, in the embodiment shown in Figure 3A, the third grid line 33 is located below the plurality of second grid lines 32 and is in contact with any of the plurality of second grid lines 32. To better understand the structure of the solar cell sheet 400, in a specific printing process, the first grid line 31 and the third grid line 33 can be printed first, and then the second grid line 32 containing silver can be printed. Preferably, in some embodiments of the present invention, the first grid line 31 and the third grid line 33 are made of the same material and can be integrally molded and printed using a mold. In other embodiments, the first grid line 31 and the third grid line 33 can also be printed in multiple layers.

[0045] Similarly, the configurations shown in Figures 3A and 3B are designed to improve battery efficiency by positioning the second grid line 32 above the first grid line 31 and the third grid line 33, thereby preventing contact with the reaction layer 20 and reducing damage to the reaction layer 20. Furthermore, compared to Example 1, the solar cell sheet 300 provided in this embodiment increases the number of third grid lines 33 that are distinguishable from the first grid line 31, thereby improving the efficiency of the integrated current.

[0046] Example 3 Figure 4A is a schematic diagram of the grid line arrangement of a solar cell sheet 400 according to Embodiment 3 of the present invention. Figure 4B is a cross-sectional view of the solar cell sheet 400 shown in Figure 4A. Embodiment 3 is a further modification based on Embodiment 2. In the embodiments shown in Figures 4A to 4B, the solar cell sheet 400 includes, in addition to the solar cell sheet 300 shown in Figures 3A to 3B, a plurality of fourth grid lines 34 extending along a second direction Y and arranged along a first direction X, wherein the plurality of fourth grid lines 34 are located above the third grid lines 33, and the plurality of second grid lines 32 cross the plurality of third grid lines 33 and the plurality of fourth grid lines 34 in the arrangement direction, wherein the fourth grid lines 34 are made of the same material as the second grid lines 32 (or can be understood as the main grid).

[0047] As shown in Figure 4A, the solar cell sheet 400 provided in this embodiment, compared to Embodiment 3, is further provided with a plurality of first grid lines 31 extending along a first direction X and arranged along a second direction Y, a plurality of second grid lines 32 extending along a first direction X and arranged along a second direction Y, a plurality of third grid lines 33 extending along a second direction Y and arranged along a first direction X, and a plurality of fourth grids 34 extending along a second direction Y and arranged along a first direction X, wherein the plurality of fourth grid lines 34 are located on the third grid lines 33. In the embodiment shown in Figure 4A, the fourth grid lines 34 are located on each third grid line 33, but it should be understood that the present invention is not limited thereto. In some other embodiments of the present invention, the fourth grid lines 34 are located on only a portion of the third grid lines 33, and there are also third grid lines 33 on which the fourth grid lines 34 are not located.

[0048] Furthermore, in this embodiment, the material of the fourth grid line 34 is the same as that of the second grid line 32. To better understand the structure of the solar cell sheet 400, in the specific printing process, the first grid line 31 and the third grid line 33 can be printed first, followed by the second grid line 32 and the fourth grid line 34. Similarly, in some embodiments of the present invention, the first grid line 31 and the third grid line 33 are made of the same material, and the second grid line 32 and the fourth grid line 34 are also made of the same material, so these two sets of grid lines can be integrally molded and printed using a mold. In some other embodiments, each grid line can also be printed separately.

[0049] Similarly, the structure of the solar cell sheet 400 shown in Figures 4A and 4B avoids contact between the silver-containing material and the reaction layer 20 by positioning the second grid line 32 and the fourth grid line 34 above the first grid line 31 and the third grid line 33. Compared to Example 2, this embodiment, based on the above embodiments, can more efficiently collect current in the welded structure 40 by adding a fourth grid line 34 (mate grid) in the Y direction, thereby improving the efficiency of the solar cell and further enhancing the stability and reliability of the solar cell.

[0050] Example 4 Figure 5 is a schematic diagram of the grid line arrangement of a solar cell sheet 500 according to Embodiment 4 of the present invention. Embodiment 4 can be understood as a further modification of Embodiment 3 shown based on Figures 4A to 4B. In the embodiment shown in Figure 5, one surface of the solar cell sheet has only a plurality of second grid lines 34 extending along a second direction Y and arranged along a first direction X, and the solar cell sheet 500 further includes a plurality of third grid lines 33 extending in the second direction Y and arranged along the first direction X, wherein the plurality of second grid lines 34 are located on the third grid lines 33, provided that the third grid lines 33 are made of the same material as the first grid lines 31. In this embodiment, the first grid lines 31 and the third grid lines 33 can be understood as fine grids, the second grid lines 34 can be understood as main grids, the second grid lines 34 are in the same direction as the third grid lines 33, and the second grid lines 34 are located on all of the third grid lines 33. Alternatively, in some embodiments, the second grid line 34 is located only on a portion of a plurality of third grid lines 33, and there are also portions of the third grid lines 33 on which the second grid line 34 is not located.

[0051] In this embodiment, compared to the solar cell sheet 400 shown in Figures 4A to 4B, by leaving only the second grid line 34 extending in the Y direction on either surface of the solar cell sheet 500, the above technical effects can be guaranteed while reducing the consumption of silver slurry and saving costs.

[0052] Example 5 Figure 6 is a schematic diagram of a solar cell sheet 600 according to Embodiment 5 of the present invention. Exemplarily, the solar cell sheet 600 shown in Figure 6 can be combined with the solar cell sheets 200 to 500 of Embodiments 1 to 4 described above with reference to Figures 2A to 5 to form more embodiments.

[0053] Specifically, as shown in Figure 6, in the solar cell sheet 600, the arrangement of multiple second grid lines 32 above multiple first grid lines 31 is such that the second grid lines 32 partially or completely surround the first grid lines 31. This means that, in the embodiment shown in Figure 6, a portion of the second grid lines 32 can come into contact with the reaction layer 20.

[0054] Exemplary, when some of the second grid lines 32 completely surround the first grid lines 31, the width of the second grid lines 32 can be greater than that of the first grid lines 31, i.e., a portion of the main grid is covered on both the left and right sides of the fine grid. In this embodiment, the top surface and both sides of the first grid lines 31 are covered with a portion of the second grid lines (containing silver), and this silver-containing component can enhance the light reflection effect and increase the efficiency of the solar cell. In other embodiments, the second grid lines 32 partially surround the first grid lines 31, i.e., one side of the left and right sides of the first grid lines 31 is covered with the silver-containing component of the second grid lines 32, while the other side is exposed. In this embodiment, the top surface of the first grid lines 31 is similarly covered with the silver-containing component of the second grid lines, and the bottom surface is in contact with the reaction layer 20. Whether the second grid line 32 partially or completely surrounds the first grid line 31, it is still in contact with a portion of the reaction layer 20. However, the contact area is reduced, and it is understood that this technology can achieve the effect of reducing losses and improving efficiency compared to a conventional structure in which the main grid is in complete contact with the reaction layer.

[0055] On the other hand, in some of the above-described embodiments of the present invention, the connection structure 40 can be replaced with a connection structure of other material and shape, such as welding paste, in order to connect multiple battery sheets by contacting multiple second grid lines 32, in addition to the welding band shown in each drawing.

[0056] Furthermore, at least a portion of the second grid line structure of at least one of the solar cell sheets provided by the present invention does not come into contact with the reaction layer of the solar cell sheet. In the drawings of the above-described embodiments 1 to 4 of the present invention, preferably, none of the second grid lines come into contact with the reaction layer, or only a portion of them come into contact with the reaction layer, but the present invention is not limited to such a structure. In particular, the degree of contact between the second grid line structure and the reaction layer of the solar cell sheet and the specific contact method are not limited to the embodiments described above.

[0057] Specifically, in some other embodiments of the present invention, taking as an example that both the first grid line structure and the second grid line structure are linear structures, one or more of the second grid lines are in contact with part or all of the reaction layer. Alternatively, a portion of any of the one or more second grid lines may be in contact with the reaction layer. In some embodiments, a portion of the second grid line is in direct contact with the reaction layer, a portion of the second grid line is printed on the first grid line and the portion of the second grid line is located on the first grid line, and includes second grid lines that are not in complete contact with the reaction layer, and / or second grid lines that are not in contact with the reaction layer only in some positions. If all of the one or more of the above-described second grid line structures are in contact with the reaction layer, it is understood that a portion of the second grid line (i.e., the main grid) may be modified based on the prior art (where the main grid is in complete contact with the reaction layer) to the arrangement method provided for the present invention.

[0058] Furthermore, in Example 5 of the present invention, a specific method was provided in which at least a portion of the second grid line structure does not come into contact with the reaction layer, that is, a method in which the second grid line is positioned above the first grid line in a manner that partially or completely surrounds it.

[0059] Regardless of which of the above embodiments is adopted, the solar cell sheet proposed by the present invention reduces contact between the main grid and the reaction layer by preventing at least a portion of the region of at least one second grid line structure from contacting the reaction layer of the solar cell sheet, thereby strengthening the connection between the main grid and the weld band, and improving efficiency and the stability and reliability of the solar cell.

[0060] Figure 7 is a flowchart of the solar cell sheet manufacturing method 70 of the present invention. As shown in Figure 7, the present invention provides a solar cell sheet manufacturing method 70 applied to the manufacture of a solar cell sheet. The solar cell sheet manufacturing method 70 includes the following steps:

[0061] S101: Print multiple first grid line structures onto one of the surfaces of the solar cell sheet.

[0062] S102: Multiple second grid line structures are printed on the surface, the multiple second grid line structures are located on top of multiple first grid line structures, and at least a portion of at least one second grid line structure does not come into contact with the reaction layer of the solar cell sheet.

[0063] In step S102 described above, the multiple second grid wire structures are applied so as to contact the connection structures between the multiple battery seals.

[0064] The method for manufacturing a solar cell sheet provided in this embodiment can be applied to solar cell sheets in all embodiments referring to Figures 2A to 6 described above. Details of the solar cell sheet manufacturing method 70 can be found in the description above and are omitted here.

[0065] Furthermore, the present invention provides a solar cell string based on the structure of the solar cell sheet described above. The solar cell string includes a solar cell sheet proposed by the present invention, for example, a solar cell sheet described in any of the above embodiments, wherein the connection structure is such that two adjacent solar cell sheets are connected sequentially to form the solar cell string.

[0066] Accordingly, the present invention further provides a method for manufacturing a solar cell string. Figure 8 is a flowchart of a solar cell string manufacturing method 80 according to one embodiment of the present invention. As shown in Figure 8, the solar cell string manufacturing method 80 includes the following steps:

[0067] S201: Provides a plurality of battery sheets, each including a positive electrode surface and a negative electrode surface, the positive electrode surface and / or the negative electrode surface having a plurality of first grid line structures and a plurality of second grid line structures, the plurality of second grid line structures located on top of the plurality of first grid line structures, and at least a portion of the region of at least one second grid line structure is not in contact with the reaction layer of the solar cell sheet.

[0068] S202: Multiple battery sheets are connected in series by sequentially connecting the positive and negative electrode surfaces of each battery sheet using multiple connection structures. In this step, the connection structures contact the second grid wire structure on the positive and / or negative electrode surfaces.

[0069] Specifically, in one embodiment of the present invention, each battery sheet in step S201 includes opposing positive electrode surfaces and negative electrode surfaces, and both the positive electrode surface and the negative electrode surface are provided with a plurality of first grid lines extending along a first direction and arranged along a second direction, and a plurality of second grid lines extending along a first direction and arranged along a second direction, and / or extending along a second direction and arranged along a first direction, wherein the plurality of second grid lines are located on at least some of the plurality of first grid lines. Each connection structure in step S202 is welded to the second grid lines so as to straddle the plurality of first grid lines. Furthermore, in some other embodiments of the present invention, if the battery sheet has only a grid line structure on one side, the first grid line structure and the second grid line structure proposed by the present invention can be manufactured in the positive and negative electrode regions on this one side, respectively, using the manufacturing method 70 described above. Similarly, the manufacturing method 80 for the solar cell string can be described in the above description, so it will not be described further here.

[0070] Finally, it is necessary to further explain the grid line structure of the solar cell sheet of the present invention. In the present invention, the terms "first" and "second" are used to refer to the first and second grid line structures in the solar cell sheet in order to distinguish grid line structures that are located at different positions or in different layers relative to the reaction layer on the surface of the solar cell sheet. In some embodiments of the present invention, there may be clear or additional boundaries between the first grid line structure and the second grid line structure, or there may not be clear boundaries between them, and they may even form special boundary layers with respect to each other through material penetration. The following will be explained in detail with reference to Figures 9a to 9c, but in the embodiments shown in Figures 9a to 9c, it can be said that both the first and second grid line structures are still multi-line / multi-stage linear structures.

[0071] As shown in Figure 9a, this embodiment further includes a connecting layer 90 between the first grid line 91 and the second grid line 92, which can strengthen the connection between the first grid line 91 and the second grid line 92. Exemplarily, the material of the connecting layer 90 can be selected from one or more materials, including inorganic materials, organic materials, and metals, and the present invention is not limited thereto. In particular, the connecting layer 90 may be a layer completely independent of the first grid line 91 and the second grid line 92, but in some embodiments of the present invention, it is not excluded that the connecting layer 90 may contain some material from the first grid line 91 and the second grid line 92 in order to allow material permeation to occur. In such embodiments, the presence of the connecting layer can improve the connection strength between the first grid line structure and the second grid line structure, thereby further improving the stability of the battery.

[0072] Furthermore, in the embodiments shown in Figures 9b and 9c, the first grid line 91 and the second grid line 92 are still in direct contact with each other, but unlike the embodiment shown in Figure 9a, component penetration occurs in the portion (contact surface) where the first grid line 91 and the second grid line 92 are in contact with each other, so that boundary layers 900 and 900' as shown in Figures 9b and 9c are formed. Both boundary layer 900 and boundary layer 900' contain some of the first grid line 91 and / or the second grid line 92. In such embodiments, the contact resistance between the first grid line 91 and the second grid line 92 becomes relatively small, and the connection force between them becomes relatively strong, so that a more optimized solar cell sheet is realized.

[0073] As can be seen from Figures 9b and 9c, the difference in cross-sectional heights shown in the drawings of boundary layers 900 and 900' means that there are some differences in the material composition of the first grid lines 91 and / or the second grid lines 92 included in the boundary layers in the two embodiments. Exemplarily, in some embodiments of the present invention, the first grid line structure included in the boundary layer accounts for 1% to 99% of the first grid line structure before the component penetration occurs, and the second grid line structure included in the boundary layer accounts for 1% to 99% of the second grid line structure before the component penetration occurs. This means that in embodiments where component penetration occurs, the technical effects of the present invention can be achieved if it can be ensured that a portion of the second grid line structure (e.g., the second grid line 92) is not in contact with the reaction layer 20.

[0074] According to the solar cell sheet and battery string provided by the present invention, by printing the main grid on a fine grid and then welding the main grid to the connecting structure, hollow welding due to insufficient height of the main grid is avoided, contact between the main grid and the reaction layer 20 is effectively reduced, the connection between the main grid and the connecting structure is strengthened, the current efficiency of the battery sheet is increased, and the service life of the solar cell sheet is extended.

[0075] While the above describes the basic concepts, it will be obvious to those skilled in the art that the above disclosure is merely an example and does not limit the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to the present application. Such modifications, improvements, and amendments are proposed in the present application and therefore fall within the spirit and scope of the exemplary embodiments of the present application.

[0076] At the same time, this application uses specific terminology to describe embodiments of the application. For example, “one embodiment,” “one example,” and / or “several embodiments” mean features, configurations, or characteristics relating to at least one embodiment of the application. Accordingly, it should be emphasized and noted that “one example,” “one example,” or “one alternative embodiment” mentioned more than once in different places in this specification do not necessarily mean the same embodiment. Furthermore, several features, configurations, or characteristics in one or more embodiments of the application can be appropriately combined.

[0077] Similarly, in order to simplify the language disclosed herein and facilitate the understanding of the embodiments of one or more applications, please note that in the preceding descriptions of embodiments herein, multiple features may be combined into a single embodiment, drawing, or description thereof. However, this method of disclosure does not mean that there are more features required for the subject matter of this application than the features described in the claims. In fact, the features of an embodiment are fewer than all the features of a single embodiment disclosed above.

[0078] In some embodiments, numbers are used to describe the number of components and attributes, but it should be understood that in some embodiments, numbers used to describe such embodiments are modified using modifiers such as “about,” “approximately,” or “roughly.” Unless otherwise stated, “about,” “approximately,” or “roughly” means that the numerical value is allowed to vary by ±20%. Accordingly, in some embodiments, numerical parameters used in the specification and claims are approximations, and these approximations may be modified depending on the features required for the individual embodiment. In some embodiments, numerical parameters should employ a general method of digit preservation, taking into account a predetermined number of significant digits. In some embodiments of this application, numerical fields and parameters used to confirm their range are approximations, but in certain embodiments, the setting of such numerical values ​​is as precise as possible.

[0079] While this application is described with reference to current specific embodiments, it should be noted that those skilled in the art will recognize that the above embodiments are used solely for illustrative purposes of this application, and that various equivalent modifications or substitutions are possible without departing from the spirit of this application, and therefore, any modifications or variations of the above embodiments within the spirit of this application will fall within the scope of the claims of this application. [Explanation of symbols]

[0080] 10 silicon wafers 11 Main Grid 12 fine grid 20 Reaction layer 31. First grid line 32. Second grid line 33. Third grid line 34. The fourth grid line 40 Connection Structure 90 Connectivity Layer 91 First grid line 92 Second grid line 100, 200, 300, 400, 500, 600 solar cell sheets 900, 900' boundary layer

Claims

1. A solar cell string comprising a solar cell sheet and a connecting structure, The aforementioned connection structure connects two adjacent solar cell sheets in sequence. At least one surface of the solar cell sheet is A plurality of first grid line structures, each comprising a plurality of first grid lines extending along a first direction and arranged along a second direction, and a plurality of third grid lines extending along the second direction and arranged along the first direction, A plurality of second grid line structures, each located on a plurality of first grid line structures and comprising a plurality of second grid lines, wherein at least a portion of the region of at least one second grid line structure does not contact the reaction layer of the solar cell sheet, and the second grid line structure further comprises a plurality of fourth grid lines extending along the second direction and arranged along the first direction, wherein the plurality of fourth grid lines are located on at least a portion of the third grid lines, and the plurality of second grid lines span the plurality of third grid lines and the plurality of fourth grid lines. Equipped with, Multiple of the aforementioned second grid line structures are applied to contact the connection structure, A solar cell string characterized in that at least a first portion of a plurality of the second grid line structures extends along the first direction and is arranged along the second direction, and the first portions of the plurality of the second grid line structures are spaced apart on the plurality of the first grid lines in both the first and second directions.

2. The plurality of the aforementioned second grid line structures comprises a plurality of linear structures and / or multi-stage linear structures. The solar cell string according to claim 1.

3. The first grid line structure also includes a linear structure, The connection structure includes a welding band or welding paste that contacts a plurality of the second grid lines. The solar cell string according to claim 2, characterized in that it is a solar cell string.

4. The plurality of second grid lines extend only in the first direction and are arranged in the second direction, and the third grid lines are made of the same material as the first grid lines. The solar cell string according to claim 3, characterized in that it is a solar cell string.

5. The fourth grid line is made of the same material as the second grid line. The solar cell string according to feature 4.

6. The arrangement in which multiple second grid lines are located on at least some of the multiple first grid lines is such that the second grid lines partially or completely surround the first grid lines. A solar cell string according to any one of claims 3 to 5, characterized by the above.

7. The solar cell sheet further comprises a connecting layer located between the first grid line structure and the second grid line structure. A solar cell string according to claim 1 or 2, characterized by the features described above.

8. The connecting layer consists of at least one of inorganic material, organic material, and metal. The solar cell string according to feature 7.

9. A method for manufacturing solar cell strings, The aforementioned solar cell string includes solar cell sheets and a connecting structure, The aforementioned connection structure connects two adjacent solar cell sheets in sequence, and the method is A step of printing a plurality of first grid line structures on at least one surface of the solar cell sheet, wherein the plurality of first grid line structures include a plurality of first grid lines extending along a first direction and arranged along a second direction, and a plurality of third grid lines extending along the second direction and arranged along the first direction. A step of printing a plurality of second grid line structures on the surface, wherein the plurality of second grid line structures are located on a plurality of first grid line structures, the plurality of second grid line structures include a plurality of second grid lines, and at least a portion of at least one second grid line structure does not come into contact with the reaction layer of the solar cell sheet, wherein the second grid line structure further includes a plurality of fourth grid lines extending along the second direction and arranged along the first direction, the plurality of fourth grid lines are located on at least a portion of the third grid lines, and the plurality of second grid lines span the plurality of third grid lines and the plurality of fourth grid lines, Equipped with, Multiple of the second grid line structures are applied so as to be in contact with the connection structure. A method for manufacturing a solar cell string, characterized in that at least a first portion of a plurality of second grid line structures extends along a first direction and is arranged along a second direction, and the first portions of the plurality of second grid line structures are arranged on the plurality of first grid lines with spacing in both the first and second directions.

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