Solar cell string and preparation method thereof

Abstract

The present invention provides a solar cell string and a method for preparing the same. The solar cell string includes: a plurality of cells, each cell including two opposite surfaces, each surface having: a plurality of grid lines extending along a first direction and arranged along a second direction; a plurality of connection areas, each connection area having an adhesive and a conductive ring surrounding the adhesive, the conductive ring being in contact with at least one grid line; and a plurality of welding strips, each welding strip spanning across a plurality of grid lines and fixedly bonded to the adhesive on at least two connection areas, each welding strip being in contact with the conductive ring and at least one grid line other than the grid line; wherein each welding strip sequentially connects two adjacent cells to form a cell string. The solar cell string and the method for preparing the same of the present invention can simply and conveniently realize the connection of main grid-free solar cells, while reducing the silver paste consumption when preparing the cells.

Description

Technical Field

[0001] The present invention mainly relates to the field of photovoltaic technology, and in particular to a solar cell string and a preparation method thereof. Background Art

[0002] Solar cells with main grid, such as Figure 1 As shown, the battery series connection method is to use a welding ribbon 11, which is usually in the form of a flat welding ribbon. The welding ribbon is generally about 1.0-2mm wide, the copper base thickness is 0.1-0.15mm, and the single-sided coating thickness is about 0.015-0.030mm. During the connection, the solder must be melted at high temperature, and then the main grids on the batteries are welded together. This consumes a large amount of silver paste, the preparation process is complex, and the resulting battery will cause a large light-blocking area.

[0003] To solve this problem, the field has developed multi-busbar batteries, which can greatly reduce the span of the busbars by increasing the number of busbars. However, it still uses welding to bond the ribbon to the battery. In order to enhance the connection performance, Figure 1 As shown, pad points 12, i.e., larger silver electrode points, are printed at the welding points to increase the welding tension. This method of increasing the number of main grid lines is still based on the improvement of existing technology. Although it can partially reduce the amount of silver paste used and the light shielding area, the degree of improvement is limited. In addition, the welding method is inevitably used, which is also prone to causing hidden cracks in the cell.

[0004] The best way to improve the use of screen-printed busbars is to completely eliminate them. However, the technical difficulty in completely avoiding busbars lies in how to connect the cells in series. Currently, existing technologies offer a polymer film that is first bonded to the wires, then placed on the cells, and finally laminated. This technology can completely eliminate the use of busbars, but the film requires a special structure and must be bonded to the wires before being fixed to the cells, which increases the process complexity.

[0005] Therefore, the field still lacks a complete preparation process and structure for solar cells with main grids that can avoid the above problems. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a solar cell string that can simply and conveniently realize the connection of busbar-less solar cell sheets while reducing the silver paste consumption when preparing the cell string.

[0007] To solve the above technical problems, the present invention provides a solar cell string, comprising: a plurality of cell sheets, each cell sheet comprising two opposite surfaces, each surface having: a plurality of grid lines arranged along a first direction, suitable for providing a path for current; a plurality of connection areas arranged along a second direction, each connection area having an adhesive; and a plurality of welding ribbons, each welding ribbon spanning the plurality of grid lines; wherein each welding ribbon sequentially connects two adjacent cell sheets to form the cell string.

[0008] In one embodiment of the present invention, each connection area also has a conductive ring surrounding the adhesive, and at least one gate line passes through the conductive ring, and each welding strip is fixedly bonded to the adhesive on at least two connection areas, and each welding strip is in contact with the conductive ring and the gate lines other than the at least one gate line.

[0009] In one embodiment of the present invention, the plurality of connection regions arranged along the second direction are arranged in order along the first direction.

[0010] In one embodiment of the present invention, at least one connection area among the plurality of connection areas is rectangular or circular in shape.

[0011] In one embodiment of the present invention, a hot melt adhesive layer and a glass layer are sequentially attached to the surface of each cell.

[0012] In one embodiment of the present invention, a thin adhesive film is further covered between the surface of the battery cell and the hot melt adhesive layer. The thin adhesive film includes a single layer film and / or a composite film, and the side of the thin adhesive film close to the battery cell is sticky.

[0013] In one embodiment of the present invention, the soldering ribbon includes a conductive wire layer and a wrapping coating.

[0014] In one embodiment of the present invention, the wire layer includes a metal wire, the wrapping coating includes a metal and / or alloy, including a low-temperature alloy, and the melting point of the low-temperature alloy is 120-150°C.

[0015] Another aspect of the present invention also proposes a method for preparing a solar cell string, comprising the following steps: providing a plurality of cell sheets, each cell sheet comprising a relative positive electrode surface and a negative electrode surface, the positive electrode surface and the negative electrode surface both having a plurality of grid lines arranged along a first direction, and a plurality of connection areas arranged along a second direction, each connection area having a conductive ring and the conductive ring being in contact with at least one grid line; adhering an adhesive to each of the connection areas along the second direction; connecting a plurality of welding ribbons to the positive electrode surface and the negative electrode surface of each cell sheet in sequence to connect the plurality of cell sheets in series, each welding ribbon after connection spanning the plurality of grid lines and fixedly bonded to the adhesive on at least two connection areas, each welding ribbon being in contact with the conductive ring and grid lines other than the at least one grid line, and the polarity of the surfaces of two adjacent cell sheets bonded with the welding ribbons being different; and laminating the plurality of cell sheets bonded with the welding ribbons and connected in series to obtain a cell string.

[0016] In one embodiment of the present invention, when the adhesive is in liquid form, the method further includes curing the adhesive before laminating the plurality of battery cells.

[0017] In one embodiment of the present invention, before laminating the plurality of battery cells, a hot melt adhesive film and glass are placed on the upper and lower surfaces of each battery cell.

[0018] Compared with the prior art, the present invention has the following advantages: through the solar cell string and the preparation method of the present invention, the connection of main grid-less solar cell sheets can be simply and conveniently realized, while reducing the silver paste consumption when preparing the cell string; and, covering the cell sheets with structures such as a thin adhesive film, a hot melt adhesive layer and a glass layer can further protect the cell string, optimize the preparation process of the cell string, and improve the stability and reliability of the cell string. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of the present application, are incorporated into and constitute a part of this application, illustrate embodiments of the present application, and together with this specification serve to explain the principles of the present invention. In the accompanying drawings:

[0020] Figure 1 This is a schematic diagram of a solar cell string;

[0021] Figure 2a and 2b This is a partial structural diagram and a partial enlarged diagram of a solar cell string according to an embodiment of the present invention;

[0022] Figure 3a and 3b is a partial structural schematic diagram and a partial enlarged view of a solar cell string according to another embodiment of the present invention;

[0023] Figure 4 is an exploded schematic diagram of a solar cell string according to an embodiment of the present invention;

[0024] Figure 5 The solar cell string of one embodiment of the present invention is as follows Figure 4 A cross-sectional view taken along the AA direction is shown; and

[0025] Figure 6 FIG. 4 is a flow chart of a method for preparing a solar cell string according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0027] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0028] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0029] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0030] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0031] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is solely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. Furthermore, while the terms used in this application are selected from commonly known and commonly used terms, some terms mentioned in this specification may have been selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of this description. Furthermore, this application should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0032] It should be understood that when a component is referred to as being “on another component,” “connected to another component,” “coupled to another component,” or “contacting another component,” it can be directly on, connected to, coupled to, or contacting the other component, or intervening components may be present. In contrast, when a component is referred to as being “directly on another component,” “directly connected to,” “directly coupled to,” or “directly contacting” another component, there are no intervening components. Similarly, when a first component is referred to as being “electrically in contact with” or “electrically coupled to” a second component, an electrical path exists between the first and second components that allows current to flow. This electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even without direct contact between the conductive components.

[0033] One embodiment of the present invention provides a solar cell string that can simply and conveniently connect busbar-less solar cells while reducing silver paste consumption during the preparation of the cell string.

[0034] like Figure 2a and 2b 1 is a partial structural diagram and a partially enlarged view of a solar cell string 200 according to an embodiment of the present invention.

[0035] like Figure 2a As shown, the battery string 200 includes a plurality of battery cells 20. Each battery cell 20 has a thickness in a three-dimensional space and includes two opposite upper and lower surfaces. The two surfaces have different electrical polarities, namely positive and negative electrodes.

[0036] like Figure 2b As shown in the partial enlarged view, each surface has a plurality of grid lines 21 arranged along the first direction X. The plurality of grid lines 21 are suitable for providing a path for the photocurrent of the solar cell panel 20, that is, for deriving and transmitting the photocurrent.

[0037] For example, in one embodiment of the present invention, the width of the gate line 21 may be in the range of 0.1 μm to 100 μm, and the height of the gate line 21 may be in the range of 1 to 50 μm, but the present invention is not limited thereto.

[0038] Furthermore, each surface also has a plurality of connection areas 22 arranged along the second direction Y.

[0039] For example, the area of the connection region may range from 0.1 to 50 mm. 2 Preferably, several gate lines 21 pass through one connection region 22 .

[0040] In such Figures 2a-2bIn the embodiment shown, each connection area 22 has the same shape and is circular. Moreover, the plurality of circular connection areas 22 arranged along the second direction Y are also arranged in an orderly manner in the first direction X. However, the present invention does not Figures 2a-2b The connection regions shown have the same shape and are arranged in an orderly manner along the first direction X. In other embodiments, the multiple connection regions may have different shapes and be arranged in a random order. For example, in some embodiments, the multiple connection regions may all be rectangular or circular, or may have a combination of rectangular, circular, and other irregular shapes.

[0041] In such Figures 2a-2b In the illustrated embodiment, each connection region further has an adhesive (not shown) and a conductive ring surrounding the adhesive (ie, the edge of the connection region 22 ), and the conductive ring contacts at least one gate line 21 .

[0042] Specifically, in Figures 2a-2b In the figure, the adhesive is not shown, but it can be understood that the adhesive is located on each connection area 22 and is used to adhere the soldering ribbon 23 to the surface of the battery cell. Furthermore, the conductive ring is the edge of the connection area 22. Within the area circled by the conductive ring, the adhesive is attached and adheres to the soldering ribbon 23, thereby providing a demarcated area for the soldering ribbon 23 to adhere to the battery surface. Figures 2a-2b In the embodiment shown, the circular conductive ring is in contact with two gate lines at the outermost side of its circumference, but the present invention does not Figures 2a-2b The contact method shown is limited to the following examples. Figure 2a-2b Contact in a tangential manner.

[0043] It should be noted that the present invention does not limit the form of the above-mentioned adhesive. For example, it can be liquid or solid, and its types include but are not limited to UV glue, multi-purpose glue, and ordinary tape. In some other embodiments of the present invention, the above-mentioned connection area 22 can also be the blank space between two adjacent grid lines 21. As long as the adhesive is attached to the area, the area with the adhesive can be considered as the connection area.

[0044] To better understand the structure of the connection area on the surface of each cell in the solar cell string of the present invention, the grid line electrode can be prepared using various methods in the field, such as screen printing and sintering, electroplating, and inkjet printing. Its function is to transfer carriers generated by the silicon wafer substrate and merge them into the solder ribbon. In some embodiments of the present invention, screen printing is preferably used, for example, four-screen printing.

[0045] Furthermore, the method for preparing the connection area includes pre-setting the shape of the connection area on a mold when preparing the gate line, so that the connection area and the gate line can be formed integrally when printing the gate line. After printing, a predetermined shape and number of connection areas are formed on a specific area of the solar cell surface. The edges of these connection areas are conductive because they are made of the same material as the gate line, thus forming a conductive ring. However, the invention does not limit the method for preparing the connection area.

[0046] For example, a secondary casting / printing of a certain shape and number of connection areas can be performed on the surface of a pre-formed cell with multiple grid lines, and a conductive material can be used to form a structure with multiple connection areas having conductive rings. Since the preparation process of the grid lines and connection areas is not the focus of this invention, it will not be elaborated here.

[0047] Further, such as Figure 2b As shown, each welding strip 23 spans across a plurality of grid lines 21 and is fixedly bonded to the adhesive on at least two connection areas 22 .

[0048] In such Figures 2a-2b In the illustrated embodiment, the multiple connection areas 22 arranged along the second direction Y each have the same circular shape and are arranged sequentially in the first direction X. Therefore, after each soldering ribbon 23 is bonded to the surface of the cell via the adhesive located on the multiple connection areas 22 arranged sequentially in the first direction X and the second direction Y, multiple soldering ribbons 23 are naturally formed, arranged sequentially parallel or approximately parallel to each other in the first direction X. Furthermore, each soldering ribbon 23 spans or is perpendicular to multiple grid lines in the second direction Y. In this case, each soldering ribbon 23 contacts the conductive ring of at least one connection area 22 and all other grid lines along the path in the second direction Y.

[0049] like Figure 2a and 2b As shown, each welding ribbon 23 sequentially connects two adjacent battery cells 20 to form a battery string 200. In the second direction Y, the length of the welding ribbon 23 is 1.5 to 3 times the length of each battery cell 20. For example, one side of each welding ribbon connects the positive electrode of the adjacent battery cell, and the other side connects the negative electrode of the adjacent battery cell. The battery string 200 is formed by sequentially connecting two adjacent battery cells.

[0050] Exemplarily, in one embodiment of the present invention, the size of the soldering ribbon ranges from 0 to 400 μm, preferably from 100 to 200 μm, and in order not to increase the series resistance, the number of soldering ribbons is negatively correlated with their size. Generally, the thinner the wire, the more soldering ribbons are required.

[0051] Through Figures 2a-2bThe structure of the battery string can easily and conveniently realize the connection between multiple busbar-free solar cells to form a battery string without busbar connection. Figures 2a-2b The structure of the battery string shown can effectively save the silver paste consumption when preparing battery cells.

[0052] Specifically, the solar cell string structure of the present invention only requires providing a connection area on the cell and securing the solder ribbon to the cell surface via an adhesive. Furthermore, the solder ribbon can be integrally formed during the preparation of the grid lines, effectively saving the silver paste required for the production of the cell string. For example, in one embodiment of the present invention, the cell string structure of the present invention can save approximately 70% of the silver paste required for the production of the cell string, compared to the current main grid welding structure used for the cells in the same cell string.

[0053] Furthermore, the use of a connecting zone structure and adhesively securing the solder ribbon effectively reduces the risk of EL (electroluminescence) faults and increases the reliability of the solar cell. Furthermore, the lack of a main grid effectively reduces the shading area, significantly improving the photoelectric conversion efficiency of the same solar cell.

[0054] like Figure 3a and 3b FIG. 1 is a partial structural diagram and a partial enlarged diagram of a solar cell string 30 according to another embodiment of the present invention. Figure 3b As shown, the battery string 300 includes a plurality of battery cells 30, each battery cell 30 also includes a plurality of grid lines 31, a plurality of connection areas 32 and a plurality of welding strips 33. Figures 2a-2b The embodiment shown differs in that Figures 3a-3b In the illustrated embodiment, the plurality of connection regions 32 on the battery cell 30 are rectangular in shape.

[0055] For other details about the structure and preparation process of the solar cell string 300, please refer to the above Figures 2a-2b The description of the illustrated embodiment will not be repeated here.

[0056] In general, Figures 2a-2b as well as Figures 3a-3b In the illustrated embodiment, the connection areas have the same shape, which is circular or rectangular, and the multiple connection areas arranged along the second direction Y are also arranged in order along the first direction X. However, the present invention is not limited thereto.

[0057] like Figure 4FIG2 is an exploded view of a solar cell string 400 according to an embodiment of the present invention. The solar cell string 400 also includes a plurality of solar cells 40 , with a hot melt adhesive layer 41 and a glass layer 42 attached to the upper and lower surfaces of the solar cells 40 .

[0058] For example, to better understand Figure 4 The structure of the battery string 400 shown in FIG. 1 is that a plurality of battery cells 40 are sequentially connected into a string through welding ribbons, and as shown in FIG. Figure 4 As shown, a cell layer having a plurality of cells 40 is formed, and a hot melt adhesive layer 41 and a glass layer 42 are respectively encapsulated on the upper and lower sides of the cell layer, thereby forming an encapsulated solar cell string 400.

[0059] Preferably, in one embodiment of the present invention, a thin adhesive film is placed between the surfaces of multiple cell cells and the hot-melt adhesive layer to separate the cell surfaces from the hot-melt adhesive film. This is because hot-melt adhesive films, such as EVA (Ethylene Vinyl Acetate Copolymer) films, melt during the lamination process. Applying pressure in this situation can cause solder strip deviation during lamination. Furthermore, EVA films contain oxidants and acetate groups, which can also affect the metal grid lines on the cell surfaces.

[0060] Therefore, in order to improve reliability, a thin film can be applied to the soldering ribbon after it is bonded to the surface of the battery cell. For example, the thin film has high light transmittance and does not flow into liquid at the lamination temperature. The thickness of the thin film is much smaller than the thickness of EVA, which is about 0.1 to 30 μm. For example, an OCA (Optically Clear Adhesive) film can be used. Since the thickness of the thin film is very small, it will not prevent the EVA film from being pressed tightly on the battery surface. At the same time, due to the strong fluidity of EVA at the lamination temperature, it may partially insulate the soldering ribbon from the grid lines on the battery surface. Therefore, adding a thin film between the battery surface and the hot melt adhesive layer can also effectively improve the electrical contact and enhance the reliability of the battery string.

[0061] Preferably, the thin film can also be sticky, thereby further fixing the solder strip. At the same time, the thin film is resistant to high temperatures and does not deform at high temperatures, which can effectively prevent the oxidant in the EVA film and the acetic acid factor decomposed by later aging from affecting the battery string.

[0062] like Figure 5 As shown, the present invention is as Figure 4 The cross-sectional view of the solar cell string 400 along the AA direction is shown. Figure 4 and Figure 5In the embodiment shown, the battery string 400 also includes a plurality of battery cells 40. Each battery cell 40 includes two opposite surfaces, each surface also having a plurality of grid lines (not shown), a plurality of connection areas 42, and each connection area 42 having an adhesive. There are also a plurality of welding strips 43 on the surface of the battery cell 40. Figure 4 , from left to right, also shows an enlarged schematic diagram of one of the solder strips 430 before and after being bonded to the corresponding connection area 42 and laminated.

[0063] like Figure 5 As shown, the welding ribbon 430 includes a wire layer 431 and a wrapping coating 432. Specifically, the wire layer 431 includes a metal wire, and the wrapping coating 432 includes a metal and / or alloy. Specifically, the metal wire is preferably a copper wire. Exemplarily, the material of the wrapping coating 432 is preferably a low-temperature alloy, and the melting point of the low-temperature alloy is 120 to 150°C. When the above-mentioned battery string 400 is actually prepared, the wrapping coating 432 needs to be effectively welded to the above-mentioned multiple grid lines. The welding includes forming mechanical properties and electrical properties, that is, it needs to have a certain tensile force after welding, and it can also effectively transmit current. Furthermore, different wrapping layers 432 will also have different melting points, which will correspond to different welding temperatures, thereby further determining the lamination temperature.

[0064] In order to better understand the present invention Figure 5 In the embodiment shown, the structure of the soldering ribbon 430 is shown. For example, when preparing the battery string 400, the soldering ribbon 430 is initially fixed to the adhesive on the connection area 42 by bonding, and then laminated. For example, the lamination temperature is between 80 and 300°C. During the lamination process, the wrapping coating 432 ( Figure 5 The left side of the middle part is shown as a bold black portion on the circumference of the soldering ribbon 430) and melts and flows downward to the bottom of the conductive layer 431 ( Figure 5 The solder ribbon 430 is connected to the grid lines (not shown) on the cell 40 and then fixed to the cell 40 by cooling. Finally, the excess solder ribbon at both ends of the cell string 400 can also be used to connect to the busbar 44.

[0065] The solar cell string of the present invention allows for simple and convenient connection of busbar-less solar cells while reducing silver paste consumption during string fabrication. Furthermore, covering the cells with a thin adhesive film, hot-melt adhesive layer, and glass layer further protects the string, optimizes the string fabrication process, and improves its stability and reliability.

[0066] Another aspect of the present invention provides a method for preparing a solar cell string. For example, the method can be applied to Figures 2a to 5The solar cell strings shown are, however, not limited thereto.

[0067] like Figure 6 FIG. 1 is a flow chart of a method 60 for preparing a solar cell string according to the present invention. Figure 6 Flowcharts are used to illustrate the operations performed by the system according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the various steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0068] like Figure 6 As shown, a method 60 for preparing a solar cell according to the present invention includes the following steps 601 to 604.

[0069] Step 601: providing a plurality of battery cells, each battery cell having a surface having a plurality of grid lines extending along a first direction and arranged at intervals along a second direction, and a plurality of connection regions.

[0070] For example, the structure of multiple battery cells can refer to Figure 2a and 2b The structure of the battery cell 20 shown. Each battery cell includes a positive electrode surface and a negative electrode surface facing each other, each of which has a plurality of grid lines arranged along a first direction X, and a plurality of connection areas arranged along a second direction Y, each connection area having a conductive ring that contacts at least one grid line.

[0071] It is understood that the structure of the battery cell involved in the preparation method 60 of the present invention is not based on Figure 2a and Figure 2b For example, the shapes and arrangements of the connection areas on the multiple battery cells involved in the preparation method 60 of the present invention may be different.

[0072] Step 602: Adhere an adhesive to each connection area along the second direction.

[0073] For example, for Figure 2a and Figure 2b In the battery cell shown, step 602 is to adhere the adhesive to each connection area along the second direction Y.

[0074] Step 603: Connect multiple welding ribbons to the positive electrode surface and the negative electrode surface of each battery cell in sequence to connect multiple battery cells in series.

[0075] For example, for Figure 2a and Figure 2bIn the cell shown, each soldering ribbon after connection spans multiple grid lines and is fixedly bonded to the adhesive on at least two connection areas. Each soldering ribbon contacts the conductive ring and at least one grid line other than the grid line, and the polarity of the surfaces bonded with the soldering ribbons of two adjacent cell sheets is different.

[0076] Step 604: Laminating the plurality of battery cells bonded with solder ribbons and connected in series to obtain a battery string.

[0077] Exemplarily, before laminating the plurality of battery cells, hot melt adhesive film and glass are placed on the upper and lower surfaces of each battery cell, thereby forming a battery string in which the surfaces of the battery cells are covered with hot melt adhesive film and glass.

[0078] In one embodiment of the present invention, when the adhesive on the connection area of the battery cell is in liquid form, the process further includes curing the liquid adhesive before step 604 to prevent the adhesive from flowing during lamination and affecting battery performance.

[0079] The basic concepts have been described above. It will be apparent to those skilled in the art that the above disclosures are merely illustrative and do not constitute limitations on this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to this application. Such modifications, improvements, and amendments are suggested in this application and remain within the spirit and scope of the exemplary embodiments of this application.

[0080] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0081] Similarly, it should be noted that, in order to simplify the presentation of this application and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this application sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single embodiment disclosed above.

[0082] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the settings of such numerical values are as accurate as possible within the feasible range.

[0083] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions can be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A solar cell string, characterized in that: include: A plurality of battery cells, each battery cell comprising two opposing surfaces, each surface having: A plurality of grid lines extending along the first direction and arranged at intervals along the second direction; a plurality of connection areas, each connection area having an adhesive, wherein the adhesive includes UV glue, all-purpose glue and tape; and a plurality of welding strips, each welding strip spanning the plurality of grid lines; Each of the welding strips sequentially connects two adjacent battery cells to form the battery string; The adhesive is located on each connection area, and the adhesive is used to adhere each welding ribbon to the surface of the battery cell; Each connection area also has a conductive ring surrounding the adhesive, and at least one grid line passes through the conductive ring. In addition, each welding strip is fixedly bonded to the adhesive on at least two connection areas, and each welding strip is in contact with the conductive ring and grid lines other than the at least one grid line.

2. The battery string according to claim 1, wherein: The plurality of connection regions are arranged in order in the first direction.

3. The battery string according to claim 1, wherein: At least one of the plurality of connection areas is in a rectangular or circular shape.

4. The battery string according to claim 1, wherein: A hot melt adhesive layer and a glass layer are sequentially attached to the surface of each cell.

5. The battery string according to claim 4, wherein: A thin adhesive film is also covered between the surface of the battery cell and the hot melt adhesive layer. The thin adhesive film includes a single layer film and / or a composite film, and the side of the thin adhesive film close to the battery cell is sticky.

6. The battery string according to claim 1, wherein: The welding ribbon includes a conductor layer and a wrapping coating.

7. The battery string according to claim 6, wherein: The wire layer includes a metal wire, the wrapping coating includes a metal and / or an alloy, the alloy includes a low-temperature alloy, and the melting point of the low-temperature alloy is 120-150°C.

8. The battery string according to claim 1, wherein: The length of the welding ribbon is 1.5 to 3 times the length of the battery cell.

9. The battery string according to claim 1, wherein: The plurality of connection regions are arranged along a straight line in the second direction.

10. A method for preparing a solar cell string, characterized in that: The steps include: Providing a plurality of battery cells, each battery cell including a positive electrode surface and a negative electrode surface facing each other, each of the positive electrode surface and the negative electrode surface having a plurality of grid lines extending in a first direction and spaced apart in a second direction, and a plurality of connection areas, each connection area having a conductive ring, and the conductive ring being in contact with at least one grid line; Adhere an adhesive to each of the connection areas, wherein the conductive ring surrounds the adhesive, wherein the adhesive is liquid or solid, and types of the adhesive include UV glue, universal glue, and tape; Connecting a plurality of welding ribbons to the positive electrode surface and the negative electrode surface of each of the battery cells in sequence to connect the plurality of battery cells in series, wherein each welding ribbon after connection spans the plurality of grid lines and is fixedly bonded to the adhesive on at least two connection areas, each welding ribbon contacts the conductive ring and grid lines other than the at least one grid line, and the polarity of the surfaces of two adjacent battery cells bonded with the welding ribbons is different; and The plurality of battery cells bonded with solder ribbons and connected in series are laminated to obtain a battery string.

11. The preparation method according to claim 10, characterized in that When the adhesive is in liquid state, the method further includes curing the adhesive before laminating the plurality of battery cells.

12. The preparation method according to claim 10, wherein Before laminating the plurality of battery cells, a hot melt adhesive film and glass are placed on the upper and lower surfaces of each battery cell.

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