Solar cell sheet, battery string and method of 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 relates generally to the field of solar cells, and more particularly to solar cell sheets, cell strings, and methods for manufacturing both. [Background technology]

[0002] The grid line structure of the current solar cell sheet is usually designed such that the main grid is a grid line containing silver component, and the fine grid is a grid line containing aluminum component in some cases (for example, the fine grid on the back of the P-type perc battery contains aluminum). In the actual production process, the mainstream printing method is to print the main grid line and then print the fine grid line, so that the main grid line and the fine grid line overlap to form a lap joint. When the assembly is welded, a silver-tin alloy is formed at the welding point between the main grid line and the welding band (or other connection structure between battery sheets), thereby achieving the effect of connection and conductivity. In this welding method, the current flows through the fine grid to join the main grid and flows out through the welding band, but this method of deriving the current non-linearly leads to a large resistance loss and reduces the module power. At the same time, due to the process limitations, there is also a large height difference between the main grid and the fine grid, and the height of the fine grid is obviously higher than that of the main grid, which is easy to cause hollow welding between the welding band and the main grid, causing welding failure. In addition, in the existing solar cell sheets, the main grid and the reaction layer are in direct contact with each other, which causes the reaction layer to be destroyed and reduces the efficiency. Summary of the Invention [Means for solving the problem]

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

[0004] In order to solve the above technical problems, the present invention provides a solar cell sheet, 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 first grid line structures, and at least a part of the area of ​​at least one second grid line structure does not contact a reaction layer of the solar cell sheet, and the plurality of second grid line structures are adapted to contact a connection structure between a 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 a multi-stage arc-type structure.

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

[0007] Alternatively, in one embodiment of the present invention, the first grid line structure also comprises a linear structure, the plurality of first grid line structures includes a plurality of first grid lines extending along a first direction and aligned along a second direction, the plurality of second grid line structures includes a plurality of second grid lines extending along the first direction and aligned along the second direction and / or a plurality of second grid lines extending along the second direction and aligned along the first direction, the plurality of second grid lines being located above at least a portion of the plurality of first grid lines, and the connecting structure is a welding band or welding paste contacting the plurality of second grid lines.

[0008] Alternatively, in one embodiment of the present invention, the second grid lines extend only along the first direction and are aligned along the second direction, the first grid line structure further includes a third grid lines extend along the second direction and are aligned along the first direction, the second grid lines straddle the third grid lines, and the third grid lines have 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 the second direction and aligned along the first direction, the plurality of fourth grid lines overlie at least some of the third grid lines, the plurality of second grid lines straddle the plurality of third grid lines and the plurality of fourth grid lines, and the fourth grid lines have the same material as the second grid lines.

[0010] Alternatively, in one embodiment of the present invention, the second grid lines of the solar cell sheet extend only in the second direction and are aligned along the first direction, the first grid line structure further includes a third grid lines extending along the second direction and aligned along the first direction, the second grid lines overlie at least some of the third grid lines, and the third grid lines have the same material as the first grid lines.

[0011] Alternatively, in one embodiment of the present invention, the manner in which the second grid lines are positioned over at least a portion of the first grid lines is such that the second grid lines semi-surround or fully surround the first grid lines.

[0012] Alternatively, in one embodiment of the present invention, the device further comprises a connecting layer located between the first gridline structure and the second gridline structure.

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

[0014] Alternatively, in one embodiment of the invention, a boundary layer is formed at the interface between a first grid line structure and a second grid line structure by component permeation, the boundary layer including 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 invention, the first grid line structure in the boundary layer comprises 1%-99% of the first grid line structure prior to the component permeation, and the second grid line structure in the boundary layer comprises 1%-99% of the second grid line structure prior to the component permeation.

[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, comprising the steps of: printing a plurality of first grid line structures on at least one surface of the solar cell sheet; and printing a plurality of second grid line structures on the surface, the plurality of second grid line structures being located above the plurality of first grid line structures, and at least a portion of an area of ​​at least one second grid line structure being not in contact with a reactive layer of the solar cell sheet, and the plurality of second grid line structures are applied to contact a connecting structure between a plurality of cell seals.

[0017] The present invention further provides a solar cell string, which includes a solar cell sheet according to any of the above-mentioned embodiments, and a connection structure is used to sequentially connect two adjacent solar cell sheets to form a solar cell string.

[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, 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 being located on the plurality of first grid line structures, and at least a portion of an area of ​​at least one second grid line structure not contacting a reaction layer of the solar cell sheet; and connecting the plurality of battery sheets in series by sequentially connecting the positive electrode surface and the negative electrode surface of each battery sheet with a plurality of connection structures, the connection structures contacting the second grid line structures on the positive electrode surface and / or the negative electrode surface.

[0019] Compared with the prior art, the solar cell sheet and the battery string of the present invention print the main group on the fine grid, and then directly weld the main group to the welding band, thus avoiding hollow welding caused by the lack of height of the main group. The technical idea of ​​the present invention effectively reduces the contact between the main grid and the reaction layer, strengthens the connection between the main grid and the welding band, improves the current efficiency of the battery sheet, and extends the service life of the solar cell sheet. [Brief description of the drawings]

[0020] The inclusion of the accompanying drawings is to provide a further understanding of the present application, is incorporated in and constitutes a part of this application, illustrates embodiments of the present application, and together with the description, serve to explain the principles of the present application. In the drawings: [Figure 1A] FIG. 1A is a schematic diagram of a solar cell sheet according to the prior art, viewed from the front in plan view. [Figure 1B] FIG. 1B is a front cross-sectional view of the solar cell sheet shown in FIG. 1A. [Figure 1C] FIG. 1C is a schematic diagram showing a solar cell sheet according to the prior art as viewed from the rear surface. [Figure 1D] FIG. 1D is a cross-sectional view of the back surface of the solar cell sheet shown in FIG. 1C. [Figure 2A] FIG. 2A is a schematic diagram of a solar cell sheet according to Example 1 of the present invention, viewed from the front in a plan view. [Figure 2B] FIG. 2B is a cross-sectional view of the solar cell sheet shown in FIG. 2A. [Figure 3A] FIG. 3A is a schematic diagram of a solar cell sheet according to Example 2 of the present invention, viewed from the front in a plan view. [Figure 3B] FIG. 3B is a cross-sectional view of the solar cell sheet shown in FIG. 3A. [Figure 4A] FIG. 4A is a schematic diagram of a solar cell sheet according to Example 3 of the present invention, viewed from the front in a plan view. [Figure 4B] FIG. 4B is a cross-sectional view of the solar cell sheet shown in FIG. 4A. [Diagram 5] FIG. 5 is a schematic diagram showing a solar cell sheet according to Example 4 of the present invention as viewed from the front in a plan view. [Figure 6] FIG. 6 is a cross-sectional view of a solar cell sheet according to Example 5 of the present invention. [Figure 7] FIG. 7 is a schematic diagram showing the flow of a method for producing a solar cell sheet according to one embodiment of the present invention. [Figure 8] FIG. 8 is a schematic diagram showing the flow of a method for manufacturing a solar cell string according to one embodiment of the present invention. [Figure 9A] FIG. 9a is a cross-sectional view of a solar cell sheet having a connecting or boundary layer according to one embodiment of the present invention. [Figure 9B] FIG. 9b is a cross-sectional view of a solar cell sheet having a connecting or boundary layer according to one embodiment of the present invention. [Figure 9C] FIG. 9c is a cross-sectional view of a solar cell sheet having a connecting or boundary layer according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] In order to more clearly explain the technical ideas of the embodiments of the present application, the drawings necessary for the description of the embodiments are briefly described below. Obviously, the drawings in the following description are only some examples or embodiments of the present application, and those of ordinary skill in the art can also apply the present application to other similar scenarios based on these drawings without paying inventive efforts. Unless it is obvious from the language environment or otherwise described, the same symbols in the drawings represent the same structures or operations.

[0022] As used herein and in the claims, unless the context clearly indicates otherwise, terms such as "a," "one," "a kind," and / or "the" do not specifically refer to the singular but may include the plural. In general, the terms "comprising" and "including" are used only to indicate the inclusion of specifically identified steps and elements, and do not constitute an exclusive list of steps and elements, and a method or apparatus may include other steps or elements.

[0023] Unless otherwise specified, the relative arrangement of components and steps, numerical expressions and values ​​described in these examples do not limit the scope of the present application. At the same time, it should be understood that the dimensions of each part shown in the drawings are not drawn in actual proportion to facilitate the description. Although detailed discussion may not be provided for techniques, methods and devices known to those of ordinary skill in the relevant field, such techniques, methods and devices shall be considered as part of the patented specification, where appropriate. In all examples shown and discussed herein, any specific values ​​should be construed as merely illustrative, not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that in the following drawings, similar symbols and letters indicate similar items. Thus, once an item is defined in one drawing, there is no need to further discuss it in subsequent drawings.

[0024] In the present specification, it should be understood that the orientations or positions indicated by directional terms such as "front, back, up, down, left, right", "lateral, longitudinal, vertical, horizontal" and "top, bottom" are generally based on the orientations or positions shown in the drawings, and are only for the purpose of facilitating and simplifying the description of the present application. These directional terms do not indicate or imply that a specified device or element has a particular orientation or must be configured and operated in a particular orientation, unless otherwise stated, and therefore cannot be understood to limit the scope of protection of the present application. The directional terms "inside, outside" mean the inside and outside of the profile relative to each part itself.

[0025] For ease of explanation, the spatial location of one component or feature relative to another component or feature shown in the drawings may be described herein using spatial relational terms such as "above...", "above...", "on top of...", "at the top of", etc. It will be understood that spatially relative terms are intended to include orientations of the components in use or operation other than those shown in the drawings. For example, if the components in the drawings are inverted, a component described as "above other components or structures" or "on top of other components or structures" would be positioned as "below other components or structures" or "under other components or structures". Thus, the exemplary term "above..." can include two orientations: "above..." and "below...". The components may also be positioned in other different ways (rotated 90 degrees or at other orientations) and appropriately described with respect to the spatially relative terms used herein.

[0026] It should also be explained that the use of terms such as "first" and "second" to limit the components is merely for the purpose of making it easier to distinguish corresponding components, and unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limitations on the scope of protection of the present application. Furthermore, although the terms used in the present application are selected from known terms, some of the terms described in the specification of the present application are selected by the applicant at his / her own discretion, and their detailed meanings will be explained in the relevant parts of the description of this specification. It is also required to understand the present application not only by the actual terms used but also by the meanings contained in each term.

[0027] When a component is referred to as being "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 another component, or there may be an interposed component. In contrast, when a component is referred to as being "directly on," "directly connected to," "directly coupled to," or "in direct contact with" another component, there is no interposed component. Similarly, when a component is referred to as being "in electrical contact" or "electrically coupled to" another component, there is an electrical path between the first and second components that can carry electrical current. This electrical path may include capacitors, coupled inductors, and / or other components that can carry electrical current, and may not be in direct contact between conductive members.

[0028] Flowcharts are used herein to illustrate operations performed by systems according to embodiments of the present disclosure. It should be understood that the operations described above or below are not necessarily performed in exact order. Conversely, various steps may be processed in reverse order or simultaneously. Also, additional operations may be added to these flows, or operations of one or more steps may be removed from these flows.

[0029] FIG. 1A is a schematic diagram of a solar cell sheet 100 of the prior art, viewed from the front. FIG. 1B is a cross-sectional view of the front of the solar cell sheet 100 shown in FIG. 1A. FIG. 1C is a schematic diagram of the solar cell sheet 100, viewed from the back. FIG. 1D is a cross-sectional view of the back of the solar cell sheet 100 shown in FIG. 1C. Since the present invention relates to a multi-layer grid line structure in a solar cell sheet, the plan views in the accompanying drawings of the present invention merely exemplify the arrangement of grid lines on the surface of a solar cell, and are slightly different from the concept of a plan view in the general sense. It is understood that the vertical positional relationship between the multi-layer grid line structures needs to be fully and in detail understood in combination with each cross-sectional view and the text description.

[0030] As shown with reference to Figs. 1A-1D, the grid line arrangement on the front side of the solar cell sheet 100 in the prior art is a method of printing the main grid 11 containing silver directly on the reactive layer 20 covering the surface of the silicon wafer 10, and then welding the connection structure 40 (e.g., a welding band) on the main grid 11. Although the configuration as shown in Figs. 1(A)-1(D) makes printing easy, the main grid 11 and the reactive layer 20 come into direct contact with each other (area surrounded by a dashed line in Fig. 1B), which destroys the reactive layer 20 and reduces the cell efficiency. In addition, as can be seen particularly from Fig. 1D, on the back side of the solar cell sheet 100, the height of the main grid 11 is lower than the fine grid 12, which makes it difficult to connect the connection structure 40 and the main grid 11, and the phenomenon of hollow welding is likely to occur, which also affects the cell efficiency. As a result, in the existing solar cell, there are some defects in the structure in which the fine gate is located above the main gate.

[0031] It should be noted that the reactive layer 20 shown in FIGS. 1A-1D and proposed below in connection with various embodiments of the present invention may be any one or more layers in the battery sheet or on the battery surface that serves the functions of PN junction, electrical conduction, passivation, reflection reduction and / or other protection, electron generation, electrical conduction, etc.

[0032] The present invention provides a solar cell sheet, in which either side of the solar cell sheet is provided with 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 part of the area of ​​at least one second grid line structure is not in contact with the reaction layer of the solar cell sheet, wherein the plurality of second grid line structures are adapted to contact the connection structure between the plurality of cell sheets, such a structure can effectively reduce the contact between the main grid and the reaction layer, strengthen the connection between the main grid and the welding band, improve the efficiency, and improve the stability and reliability of the solar cell.

[0033] It should be noted that the present invention is not limited to the type of cell. Thus, in different embodiments of the present invention, the solar cell may have two opposing surfaces or only one surface (e.g., back-junction cell 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, which will be described in detail below. On the other hand, when the solar cell has only one surface and the surface simultaneously has the positive and negative electrodes of the cell, in such an embodiment, both the first grid line structure and the second grid line structure are on the one surface. On the other hand, 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-type structures and / or a multi-stage arc-type structure. In another embodiment of the present invention, the plurality of second grid line structures include a plurality of straight-type structures and / or a multi-stage straight-type structure. In addition, the second grid line structure on the solar cell sheet of the present invention may be composed only of a plurality of arc-type structures and / or a multi-stage arc-type structure, or may be composed only of a plurality of linear structures and / or a multi-stage linear structure, or may simultaneously include a plurality of arc-type structures and / or a multi-stage arc-type structure, and a plurality of linear structures and / or a multi-stage linear structure, and the specific combination method is not specifically limited in this application.

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

[0035] In the embodiment shown in FIG. 2A-FIG. 2B, the first grid line structure 31 and the second grid line structure 32 are linear structures, and in this embodiment, the X-axis direction is the first direction and the Y-axis direction is the second direction with reference to the coordinate axes shown in FIG. 2A. The above-mentioned first direction X and second direction Y merely exemplarily show the relative positions of the arrangement of the first grid lines 31 and the second grid lines 32, and do not necessarily show that they are in an orthogonal relationship. Furthermore, what is shown in FIG. 2A and FIG. 2B is one of the surfaces of the solar cell 200, and in the case of a bifacial cell, for example, the surface may be the front or back surface. Or, in the case of a single-sided cell, what is shown in FIG. 2A and FIG. 2B is this single surface.

[0036] 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 positioned on the plurality of first grid lines 31, and a connection structure (specifically, a welding band) 40 spanning the plurality of first grid lines 31 and contacting the plurality of second grid lines 32 (specifically, may be welded onto the second grid line structure 32).

[0037] Illustratively, in the embodiment shown in FIG. 2A and 2B, the second grid lines 32 include silver (similar to the main grid in the conventional manufacturing method). Meanwhile, the first grid lines 31 can be similar to the fine grid in the conventional manufacturing method, and in some embodiments of the present invention, the first grid lines include silver, and may be, for example, the fine grid lines on the back side of a P-type perc battery. Although such an example is given, it should be understood that the present invention does not specifically limit the materials of the first grid lines and the second grid lines. As can be seen from FIG. 2(A), the solar cell sheet 200 adopts a main grid pad structure in which the second grid lines 32 (main grid) are abstracted as pad points and play the role of connection with the connection structure 40 (e.g., welding band).

[0038] Specifically, in order to position the second grid lines 32 on at least some of the first grid lines 31, in a specific printing process, the first grid lines 31 (fine grid) are first printed on the reactive layer 20 covering the silicon wafer 10, and then the second grid lines 32 (main grid) are printed so that the second grid lines 32 are positioned on the first grid lines 31. With this configuration, the contact between the second grid lines 32 and the reactive layer 20 can be effectively reduced, the loss of the reactive layer 20 can be reduced, and the battery efficiency can be improved.

[0039] 2A-2B, the second grid lines 32 are provided on each of the first grid lines 31, but such a configuration is not taken as an example in the present invention. Illustratively, in some other embodiments, the second grid lines 32 are located only on a portion of the first grid lines 31. For example, in some embodiments, the second grid lines 32 are located only on a portion of the first grid lines 31, and there are also first grid lines 31 on which the second grid lines 32 are not arranged.

[0040] As shown in Figures 2A-2B, it is understood that a preferred embodiment of the present invention is shown in which the length of the second grid lines 32 is shorter than that of the first grid lines 31, that is, the second grid lines 32 are discretely arranged on the first grid lines 31. This setting can reduce the amount of silver consumed in the second grid lines compared to the method of continuously installing them, and further reduce costs. In addition, as shown in Figure 2(A), the width of the second grid lines 32 is slightly larger than that of the first grid lines 31, and the length of the second grid lines 32 is also longer than the width of the connection structure 40, so that the current gathering effect of the first grid lines 31 can be ensured, the welding efficiency between the second grid lines 32 and the connection structure 40 can be improved, and the stability of the battery can be improved.

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

[0042] In the embodiment shown in FIGS. 3A-3B , the second grid lines 32 in the solar cell sheet extend only along the first direction X and are arranged along the second direction Y, the first grid line structure in the solar cell sheet 300 further includes third grid lines 33 extending along the second direction Y and arranged along the first direction X, and the second grid lines 32 straddle the third grid lines 33 which have the same material as the first grid lines 31.

[0043] 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 the first direction X and arranged along the second direction Y, and a plurality of third grid lines 33 extending along the second direction Y and arranged along the 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 it can be understood as a similarly fine grid).

[0044] Specifically, in the embodiment shown in FIG. 3A, the third grid line 33 is located below the plurality of second grid lines 32 and is in contact with each 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 have the same material, so that the two can be integrally molded and printed by a mold. In other embodiments, the first grid line 31 and the third grid line 33 can be printed in multiple layers.

[0045] 3A and 3B, the second grid lines 32 are positioned above the first grid lines 31 and the third grid lines 33, so that they do not come into contact with the reactive layer 20, reducing damage to the reactive layer 20 and improving cell efficiency. Also, compared with Example 1, the solar cell sheet 300 provided in this example increases the number of third grid lines 33 that are differentiated from the first grid lines 31, improving the efficiency of current accumulation.

[0046] Example 3 FIG. 4A is a schematic diagram of the arrangement of grid lines of a solar cell sheet 400 according to Example 3 of the present invention. FIG. 4B is a cross-sectional view of the solar cell sheet 400 shown in FIG. 4A. Example 3 is a further modification based on Example 2. In the embodiment shown in FIGS. 4A-4B, the solar cell sheet 400 includes, in addition to the solar cell sheet 300 shown in FIGS. 3A-3B, a plurality of fourth grid lines 34 extending along the second direction Y and arranged along the first direction X, the plurality of fourth grid lines 34 being located above the third grid lines 33, the plurality of second grid lines 32 crossing the plurality of third grid lines 33 and the plurality of fourth grid lines 34 in the arrangement direction, with the exception that the fourth grid lines 34 have the same material as the second grid lines 32 (or can be understood to be the main grid as well).

[0047] As shown in FIG. 4A, the solar cell sheet 400 provided in this embodiment is different from the solar cell sheet 300 in the embodiment 3 in that, in addition to the plurality of first grid lines 31 extending along the first direction X and arranged along the second direction Y, the plurality of second grid lines 32 extending along the first direction X and arranged along the second direction Y, and the plurality of third grid lines 33 extending along the second direction Y and arranged along the first direction X, a plurality of fourth grid lines 34 extending along the second direction Y and arranged along the first direction X are further provided, and the plurality of fourth grid lines 34 are located on the third grid lines 33. In the embodiment shown in FIG. 4A, the fourth grid lines 34 are arranged on each of the third grid lines 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 only on 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 arranged.

[0048] Furthermore, the material of the fourth grid line 34 in this embodiment is the same as that of the second grid line 32, and in order 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 and the fourth grid line 34 can be printed. Similarly, in some embodiments of the present invention, the first grid line 31 and the third grid line 33 have the same material, and the second grid line 32 and the fourth grid line 34 also have the same material, so that these two sets of grid lines can be integrally molded and printed by a mold. In some other embodiments, each grid line can be printed separately.

[0049] 4A and 4B, the structure of the solar cell sheet 400 prevents the silver-containing material from contacting the reaction layer 20 by locating the second grid line 32 and the fourth grid line 34 on the first grid line 31 and the third grid line 33. Compared with the second embodiment, the present embodiment is based on the above embodiments and adds the fourth grid line 34 (mate grid) in the Y direction, which can more efficiently collect the current in the welded structure 40, improve the efficiency of the solar cell, and further enhance the stability and reliability of the solar cell.

[0050] Example 4 FIG. 5 is a schematic diagram of the arrangement of grid lines of a solar cell sheet 500 according to Example 4 of the present invention. Example 4 can be understood as a further modified example of Example 3 shown based on FIGS. 4A-4B. In the example shown in FIG. 5, either one surface of the solar cell sheet has only a plurality of second grid lines 34 extending along the second direction Y and arranged along the first direction X, and the solar cell sheet 500 further includes a plurality of third grid lines 33 extending along the second direction Y and arranged along the first direction X, and the plurality of second grid lines 34 are located on the third grid lines 33, with the third grid lines 33 having the same material as the first grid lines 31. In this example, the first grid lines 31 and the third grid lines 33 can be understood as fine grids, and the second grid lines 34 can be understood as a main grid, 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 the third grid lines 33. Alternatively, in some embodiments, the second grid lines 34 are located only on a portion of the plurality of third grid lines 33, and there are also portions of the third grid lines 33 on which the second grid lines 34 are 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 lines 34 extending in the Y direction on either one surface of the solar cell sheet 500, it is possible to reduce the consumption of silver slurry while ensuring the above technical effects, thereby saving costs.

[0052] Example 5 Fig. 6 is a schematic diagram of a solar cell sheet 600 according to Example 5 of the present invention. Illustratively, the solar cell sheet 600 shown in Fig. 6 can be combined with the solar cell sheets 200-500 of Examples 1-4 described with reference to Figs. 2A-5 above to form more examples.

[0053] 6, in the solar cell sheet 600, the plurality of second grid lines 32 are located above the plurality of first grid lines 31 so that the second grid lines 32 partially or completely surround the first grid lines 31. This means that in the embodiment shown in FIG. 6, a part of the second grid lines 32 is allowed to contact the reactive layer 20.

[0054] Exemplarily, 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 larger than that of the first grid lines 31, i.e., the left and right sides of the fine grid are covered with parts of the main grid. In this embodiment, the upper surface and the left and right sides of the first grid lines 31 are covered with parts of the second grid lines (including silver), and the components of the silver-containing parts can improve the reflection effect of light irradiation and increase the efficiency of the solar cell. In another embodiment, the second grid lines 32 semi-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 components of the second grid lines 32, and the other side is exposed. In this embodiment, the upper surface of the first grid lines 31 is similarly covered with the silver-containing components of the second grid lines, and the lower surface is in contact with the reaction layer 20. It is understood that even if the second grid lines 32 partially surround or completely surround the first grid lines 31, they are in contact with a part of the reaction layer 20, but the contact area is small, and thus a technical effect of reducing loss and improving efficiency can be achieved, compared with a conventional structure in which the main grid is in complete contact with the reaction layer.

[0055] Meanwhile, in the above-mentioned embodiments of the present invention, in addition to the welding bands shown in the figures, the connecting structures 40 can be replaced with connecting structures of other materials and shapes, such as welding paste, to contact the plurality of second grid lines 32 and connect the plurality of battery sheets.

[0056] In addition, at least a part of the area of ​​at least one second grid line structure of the solar cell sheet provided by the present invention is not in contact with the reaction layer of the solar cell sheet. In the drawings of the above-mentioned Examples 1 to 4 of the present invention, preferably, none of the second grid lines contacts the reaction layer or only a part of them does not contact 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 manner are not limited to the above-mentioned several examples.

[0057] Specifically, in some other embodiments of the present invention, taking as an example that the first grid line structure and the second grid line structure are both linear structures, one or some of all the second grid lines contact a part or all of the reactive layer. Alternatively, among one or more second grid lines, a part of any of the second grid lines may contact the reactive layer. In some embodiments, a part of the second grid lines directly contacts the reactive layer, a part of the second grid lines is printed on the first grid lines, and the second grid lines whose part is located on the first grid lines include second grid lines that are not completely contacted with the reactive layer and / or second grid lines that are not contacted with the reactive layer only at a part of the second grid lines. In the case where one or some of the second grid line structures described above are all in contact with the reactive layer, it is understood that a part of the second grid lines (i.e., the main grid) is improved to the arrangement method provided by the present invention based on the prior art (where the main grids are all in contact with the reactive layer).

[0058] Moreover, in Example 5 of the present invention, a specific manner is provided in which at least a portion of the area of ​​the second grid line structure does not contact the reaction layer, i.e., the second grid lines are located on the first grid lines in a semi-encircling or full-encircling manner.

[0059] Regardless of which of the above aspects is adopted, the solar cell sheet proposed by the present invention has at least a part of the area of ​​at least one second grid line structure not in contact with the reaction layer of the solar cell sheet, thereby reducing the contact between the main grid and the reaction layer, strengthening the connection between the main grid and the welding band, and improving the efficiency, stability and reliability of the solar cell.

[0060] 7 is a flow chart of a method 70 for manufacturing a solar cell sheet of the present invention. As shown in FIG. 7, the present invention provides a method 70 for manufacturing a solar cell sheet, which is applied to manufacturing a solar cell sheet. The method 70 for manufacturing a solar cell sheet includes the following steps:

[0061] S101: A plurality of first grid line structures are printed on either surface of a solar cell sheet.

[0062] S102: Printing a plurality of second grid line structures on the surface, the plurality of second grid line structures overlying the plurality of first grid line structures, and at least a portion of an area of ​​at least one of the second grid line structures not contacting a reactive layer of the solar cell sheet.

[0063] In the above step S102, a plurality of second grid line structures are applied to contact the connection structures between the plurality of battery seals.

[0064] The manufacturing method of the solar cell sheet provided in this embodiment can be applied to the solar cell sheets in all the embodiments referring to Figures 2A to 6 described above, and the details of the manufacturing method 70 of the solar cell sheet can be referred to the above description, 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, which includes the solar cell sheet proposed by the present invention, for example the solar cell sheet described in any of the above embodiments, with the proviso that the connection structure sequentially connects two adjacent solar cell sheets to form a solar cell string.

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

[0067] S201: Providing a plurality of battery sheets, each battery sheet including a positive electrode surface and a negative electrode surface, with 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, the plurality of second grid line structures being located on the plurality of first grid line structures, and at least a portion of an area of ​​at least one second grid line structure not contacting a reactive layer of a solar cell sheet.

[0068] S202: Connect the multiple battery sheets in series by sequentially connecting the positive and negative surfaces of each battery sheet through multiple connection structures, in which the connection structures contact the second grid line structures on the positive and / or negative surfaces.

[0069] Specifically, in one embodiment of the present invention, each battery sheet in step S201 includes opposing positive and negative surfaces, and both the positive and negative surfaces 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 the first direction and arranged along the second direction and / or extending along the second direction and arranged along the first direction, and the plurality of second grid lines are located above 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. Also, in some other embodiments of the present invention, when the battery sheet has a grid line structure on only one side, the above-mentioned manufacturing method 70 can be used to manufacture the first grid line structure and the second grid line structure proposed by the present invention in the positive and negative electrode regions on this one side, respectively. Similarly, the above description can be referred to for the manufacturing method 80 of the solar cell string, and therefore, will not be further described here.

[0070] Finally, the grid line structure of the solar cell sheet of the present invention needs to be further explained. In the present invention, the terms "first" and "second" are used for the first and second grid line structures in the solar cell sheet in order to distinguish between grid line structures 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, the first and second grid line structures may have a clear or additional boundary between them, or may not have a clear boundary between them, and may even form a special boundary layer between them due to material penetration. Hereinafter, a specific description will be given in relation to Figures 9a to 9c, and in the embodiments shown in Figures 9a to 9c, the first and second grid line structures are still multi-line / multi-stage linear structures.

[0071] As shown in FIG. 9a, in this embodiment, a connection layer 90 is further provided 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 connection layer 90 can be selected from one or more materials selected from inorganic materials, organic materials, and metals, and the present invention is not limited thereto. In particular, the connection 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 connection layer 90 has some material of the first grid line 91 and the second grid line 92 due to material permeation in the connection layer 90. In such an embodiment, by having the connection layer, the connection strength between the first grid line structure and the second grid line structure can be improved, and the stability of the battery can be further improved.

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

[0073] As can be seen from Fig. 9b and Fig. 9c, the different heights of the boundary layers 900 and 900' on the cross-sections shown in the drawings means that there is a slight difference 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 occupies 1%-99% of the first grid line structure before the component permeation occurs, and the second grid line structure included in the boundary layer occupies 1%-99% of the second grid line structure before the component permeation occurs. This means that in the embodiments where component permeation occurs, the technical effect of the present invention can be achieved as long as it can be guaranteed that a part of the second grid line structure (e.g., the second grid lines 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, the main grid is printed on a fine grid and then the main grid and the connection structure are welded together, which avoids hollow welding caused by insufficient height of the main grid, and effectively reduces the contact between the main grid and the reaction layer 20, strengthens the connection between the main grid and the connection structure, improves the current efficiency of the battery sheet, and extends the service life of the solar cell sheet.

[0075] Although the basic concept has been described above, it is obvious to those skilled in the art that the above disclosure is merely an example, and is not intended to limit the present application. Although not expressly 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, the present application uses certain terms to describe the embodiments of the present application. For example, "one embodiment," "one embodiment," and / or "some embodiments" refer to features, configurations, or characteristics associated with at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "one embodiment" or "one alternative embodiment" mentioned two or more times in different places in this specification do not necessarily refer to the same embodiment. Furthermore, some features, configurations, or characteristics in one or more embodiments of the present application may be combined as appropriate.

[0077] Similarly, it should be noted that in the foregoing description of the embodiments of the present specification, multiple features may be combined in one embodiment, drawing, or description thereof in order to simplify the presentation of the disclosure herein and facilitate understanding of one or more of the embodiments of the application. However, this method of disclosure does not imply that the subject matter of the present application requires more features than are recited in the claims. In fact, an embodiment may have fewer than all the features of a single embodiment disclosed above.

[0078] In some examples, numbers are used to describe the number of components, attributes, but it should be understood that the numbers describing such examples are modified in some instances using the modifiers "about," "approximately," or "around." Unless otherwise specified, "about," "approximately," or "around" means that the numerical value is allowed to vary by ±20%. Accordingly, in some examples, the numerical parameters used in the specification and claims are approximations, and these approximations may be varied depending on the characteristics required for a particular example. In some examples, the numerical parameters should be calculated using a common method of preserving digits, taking into account the number of significant digits given. In some examples of the present application, the numerical fields and parameters used to determine the breadth of their ranges are approximations, but in certain examples, such numerical values ​​are set as precisely as possible within the limits of feasibility.

[0079] Although the present application has been described with reference to the present specific embodiments, it should be noted that a person of ordinary skill in the art should recognize that the above embodiments are only used to describe the present application, and various equivalent modifications or substitutions are possible without departing from the spirit of the present application, and therefore, any modifications or variations of the above embodiments within the spirit of the present application should fall within the scope of the claims of the present application. [Explanation of symbols]

[0080] 10 Silicon wafer 11 Main Grid 12 Fine Grid 20 Reaction Layer 31 First Grid Line 32 Second Grid Line 33 Third Grid Line 34 Fourth Grid Line 40 Connection structure 90 Connection Layer 91 First Grid Line 92 Second Grid Line 100, 200, 300, 400, 500, 600 solar cell sheet 900, 900' boundary layer

Claims

1. At least one surface of the solar cell sheet is a plurality of first grid line structures; a plurality of second grid line structures overlying the plurality of first grid line structures, wherein at least a portion of at least one second grid line structure does not contact a reactive layer of the solar cell sheet; Equipped with A plurality of the second grid line structures are adapted to contact connection structures between a plurality of battery sheets. A solar cell sheet comprising:

2. The plurality of second grid line structures include a plurality of arc-type structures and / or a multi-stage arc-type structure.

2. The solar cell sheet according to claim 1 .

3. The plurality of second grid line structures include a plurality of linear structures and / or a multi-stage linear structure.

2. The solar cell sheet according to claim 1 .

4. the first grid line structure also comprises linear structures; the plurality of first grid line structures includes a plurality of first grid lines extending along a first direction and arranged along a second direction; the second grid line structures include a plurality of second grid lines extending along the first direction and aligned along the second direction, and / or a plurality of second grid lines extending along the second direction and aligned along the first direction, the plurality of second grid lines overlying at least a portion of the plurality of first grid lines; The connection structure includes a weld band or weld paste contacting a plurality of the second grid lines. The solar cell sheet according to claim 3 .

5. The second grid lines extend only along the first direction and are arranged along the second direction, the first grid line structure further includes a third grid lines extending along the second direction and arranged along the first direction, the second grid lines straddle the third grid lines, and the third grid lines have the same material as the first grid lines.

5. The solar cell sheet according to claim 4.

6. 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 being located above at least some of the third grid lines, the plurality of second grid lines straddling the plurality of third grid lines and the plurality of fourth grid lines, and the fourth grid lines having the same material as the second grid lines.

6. The solar cell sheet according to claim 5.

7. The second grid lines in the solar cell sheet extend only in the second direction and are arranged along the first direction, the first grid line structure further includes a third grid lines extending along the second direction and arranged along the first direction, the second grid lines are located above at least some of the third grid lines, and the third grid lines have the same material as the first grid lines.

5. The solar cell sheet according to claim 4.

8. The manner in which the second grid lines are positioned on at least a portion of the first grid lines is such that the second grid lines semi-surround or completely surround the first grid lines. The solar cell sheet according to any one of claims 4 to 7.

9. a connecting layer located between the first gridline structure and the second gridline structure.

4. The solar cell sheet according to claim 1, wherein the solar cell sheet is a polysilicon film.

10. The connection layer is made of at least one of an inorganic material, an organic material, and a metal. The solar cell sheet according to claim 9 .

11. The interface between the first grid line structure and the second grid line structure generates a boundary layer through component permeation, the boundary layer including a portion of the first grid line structure and / or a portion of the second grid line structure.

4. The solar cell sheet according to claim 1, wherein the solar cell sheet is a polysilicon film.

12. The first grid line structure included in the boundary layer comprises 1% to 99% of the first grid line structure prior to the component permeation, and the second grid line structure included in the boundary layer comprises 1% to 99% of the second grid line structure prior to the component permeation. The solar cell sheet according to claim 11 .

13. It is applied to the production of solar cell sheets, printing a plurality of first gridline structures on at least one surface of a solar cell sheet; printing a plurality of second gridline structures on the surface, the plurality of second gridline structures overlying the plurality of first gridline structures, and wherein at least a portion of at least one second gridline structure does not contact a reactive layer of the solar cell sheet; Equipped with A plurality of the second gridline structures are adapted to contact connection structures between a plurality of battery seals. A method for producing a solar cell sheet comprising the steps of:

14. The solar cell sheet according to any one of claims 1 to 12, The solar cell sheet is connected to the adjacent two solar cell sheets in sequence by the connection structure. A solar cell string comprising:

15. providing a plurality of battery sheets, each battery sheet 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 being positioned above the plurality of first grid line structures, and at least a portion of at least one second grid line structure being free from contacting a reactive layer of the solar cell sheet; connecting the plurality of battery sheets in series by sequentially connecting the positive and negative surfaces of each of the battery sheets with a plurality of connecting structures such that the connecting structures contact the second gridline structures at the positive and / or negative surfaces; Equipped A method for manufacturing a solar cell string comprising the steps of:

Images