Back contact photovoltaic cell and method of making same, stacked cell, photovoltaic module

Abstract

The embodiment of the present application relates to the field of photovoltaic cells, and provides a back contact photovoltaic cell, a preparation method thereof, a laminated cell and a photovoltaic module, wherein the back contact photovoltaic cell comprises: a cell body, a first surface of the cell body has opposite first edges in a first direction; a welding portion, a fine grid and a short grid are arranged on the first surface; the welding portion comprises a middle welding portion and edge welding portions, the middle welding portion is arranged between a pair of edge welding portions opposite in the first direction; the short grid is arranged between the first edge and the edge welding portion; a first connecting line extends along a second direction, the first connecting line is arranged between the first edge and the edge welding portion, and the short grid and a fine grid of the same polarity adjacent to the short grid are electrically connected through the first connecting line; and the width of one end of the first connecting line close to the short grid is smaller than the width of the other end. The embodiment of the present application is at least beneficial to improving photoelectric conversion efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic cells, in particular to a back contact photovoltaic cell, a preparation method thereof, a laminated cell and a photovoltaic module. BACKGROUND

[0002] With the gradual depletion of fossil energy, photovoltaic cells are used more and more widely as a new energy alternative. Photovoltaic cells are devices that convert solar light energy into electrical energy. Photovoltaic cells use the photovoltaic principle to generate carriers, and then use electrodes to lead out the carriers, thereby facilitating the effective use of electrical energy. In order to further reduce the shading of the grid lines on the front of the photovoltaic cell, the research on BC cells (Back Contact, back contact cell) is becoming more and more in-depth.

[0003] The most notable feature of the BC cell is that the PN junction and the contact metal are both on the back of the BC cell. The front of the BC cell completely avoids the shading of the metal grid electrode, can maximize the use of incident light, reduces optical loss, and has a higher short-circuit current. SUMMARY

[0004] The present application provides a back contact photovoltaic cell, a preparation method thereof, a laminated cell and a photovoltaic module, which at least helps to improve the photoelectric conversion efficiency of the back contact photovoltaic cell.

[0005] According to some embodiments of the present application, the present application provides a back contact photovoltaic cell, comprising:

[0006] A cell body, the cell body has a first direction, a second direction and a third direction intersecting with each other; the cell body has a first surface and a second surface opposite to each other in the third direction; the first surface has a pair of opposite first edges in the first direction; the third direction is the thickness direction of the cell body; a welding portion is arranged on the first surface; the welding portion includes an intermediate welding portion and an edge welding portion, the intermediate welding portion is arranged between the edge welding portions opposite to each other in the first direction; a fine grid is arranged on the first surface, the fine grid extends discontinuously along the first direction, and a plurality of fine grids are arranged in sequence and spaced apart along the second direction; a short grid is arranged on the first surface, the short grid extends along the first direction, and the short grid is arranged between the first edge and the edge welding portion; a first connecting line extends along the second direction, the first connecting line is arranged between the first edge and the edge welding portion, and the short grid and the fine grid of the same polarity adjacent to the short grid are electrically connected by the first connecting line; wherein the width of one end of the first connecting line close to the short grid is smaller than the width of the other end.

[0007] In some embodiments, the first connecting line gradually increases in width in the first direction away from the short gate to which it is in contact with.

[0008] In some embodiments, the ratio between the width of the first connecting line near one end of the thin gate to which it is in contact with and the width of the other end of the first connecting line is 1-1.5.

[0009] In some embodiments, the width of the first connecting line near one end of the thin gate to which it is in contact with is 8-20 μm, and the width of the first connecting line near one end of the short gate to which it is in contact with is 8-15 μm.

[0010] In some embodiments, the first connecting line is cross-connected with the thin gate and / or the short gate to which it is in contact with, at least part of the first connecting line extends to one side of the thin gate away from the short gate, and / or at least part of the first connecting line extends to one side of the short gate away from the thin gate.

[0011] In some embodiments, the length of the part of the first connecting line extending to the other side of the thin gate or the short gate is 50-130 μm.

[0012] In some embodiments, a main gate is further included, the main gate extends in the second direction, and a plurality of the main gates are sequentially and spaced apart in the first direction; the thin gate is in contact with the main gate and / or the welding part of the same polarity, and the thin gate is disconnected at the position of the main gate and / or the welding part of different polarity; the main gate includes an intermediate main gate and an edge main gate, and the intermediate main gate is arranged between a pair of edge main gates opposite in the first direction; wherein the edge main gate and the edge welding part are electrically connected, and the edge main gate and the edge welding part are arranged in a staggered manner in the first direction.

[0013] In some embodiments, a second connecting line is further included, and the thin gate adjacent to and of the same polarity as the edge welding part is in contact with the thin gate through the second connecting line; wherein the width of one end of the second connecting line near the thin gate is smaller than the width of the other end.

[0014] In some embodiments, the width of one end of the second connecting line near the thin gate is 8-15 μm, and the width of one end of the second connecting line near the edge welding part is 8-20 μm.

[0015] In some embodiments, the second connecting line is cross-connected with the thin gate to which it is in contact with, and at least part of the second connecting line extends to the other side of the thin gate to which it is in contact with away from the edge welding part.

[0016] In some embodiments, the length of the part of the second connecting line extending to the other side of the fine grid is 50-130 μm.

[0017] In some embodiments, the ratio between the width of the second connecting line near one end of the edge solder part connected therewith and the width of the other end of the second connecting line is 1-1.5.

[0018] In some embodiments, the material of the first connecting line is the same as the material of the main grid, the first connecting line is in a separate structure from the fine grid and / or the short grid; and / or, the second connecting line is in an integral structure with the edge solder part connected therewith.

[0019] According to some embodiments of the present application, another aspect of the embodiments of the present application further provides a preparation method of a back contact photovoltaic cell, comprising: providing a cell piece body, the cell piece body having opposite first and second surfaces in a third direction; the third direction being the thickness direction of the cell piece body; forming a short grid and a fine grid on the first surface, the fine grid extending along a first direction, and a plurality of the fine grids being arranged in sequence and spaced apart along a second direction; the short grid being arranged in sequence and spaced apart from the fine grid in the first direction; forming a first connecting line on the first surface, the first connecting line extending along the second direction, and the first connecting line being in contact with the fine grid and the short grid; forming a solder part on the first surface, at least one of the solder parts being arranged between the short grid and the fine grid arranged in sequence and spaced apart in the first direction; wherein the width of one end of the first connecting line near the short grid is smaller than the width of the other end.

[0020] In some embodiments, in the process of forming the first connecting line, a main grid is formed on the first surface, the main grid extending along the second direction, and a plurality of the main grids being arranged in sequence and spaced apart along the first direction; the fine grid being in contact with the main grid of the same polarity and / or the solder part, and the fine grid being disconnected at the position of the main grid of different polarity and / or the solder part; wherein the first connecting line and the main grid are formed synchronously.

[0021] According to some embodiments of the present application, another aspect of the embodiments of the present application further provides a laminated cell, comprising: a bottom cell, the bottom cell being a back contact photovoltaic cell as described above, or being a back contact photovoltaic cell formed by a preparation method of a plurality of back contact photovoltaic cells as described above; and a top cell, the top cell being located on one side of the bottom cell.

[0022] According to some embodiments of this application, another aspect of this application provides a photovoltaic module, including: a battery string, which is formed by connecting multiple back-contact photovoltaic cells as described above, or formed by connecting multiple back-contact photovoltaic cells formed by the preparation method of the back-contact photovoltaic cells as described above, or formed by connecting multiple stacked cells as described above; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film away from the battery string.

[0023] The technical solution provided in this application has at least the following advantages:

[0024] In this embodiment of the back-contact photovoltaic cell, a short grid and a fine grid of the same polarity are connected by a first connecting line. This avoids the short grid being unusable due to being sandwiched between the dissimilar main grid and the welding part, while increasing the coverage of the grid line on the surface of the cell body, thereby improving the collection efficiency of the grid line for charge carriers and thus improving the photoelectric conversion efficiency of the back-contact photovoltaic cell. Since the length of the short grid is smaller than that of the fine grid, the amount of charge carriers collected and transported by the short grid is also less than that by the fine grid. The width of the first connecting line near the fine grid is greater than the width near the short grid. On the one hand, this structure guides the transport of charge carriers, directing them from the shorter short grid to the longer fine grid, reducing the connection resistance between the fine and short grids, improving the transport efficiency of charge carriers, and thus improving the photoelectric conversion efficiency of the back-contact photovoltaic cell. On the other hand, it reduces the amount of paste required to form the first connecting line, thereby reducing the production cost of the back-contact photovoltaic cell. Attached Figure Description

[0025] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a back-contact photovoltaic cell provided in one embodiment of this application;

[0027] Figure 2 for Figure 1 Enlarged structural diagram at point A;

[0028] Figure 3 This is a step diagram illustrating a method for preparing a back-contact photovoltaic cell according to an embodiment of this application.

[0029] Reference Signs List:

[0030] 100, cell body; 1001, first edge; 110, first surface; 111, main grid area; 112, fine grid area; 113, connection line area; 114, solder area; 210, main grid; 211, middle main grid; 212, edge main grid; 220, fine grid; 230, short grid; 240, first connection line; 250, second connection line; 260, edge connection line; 300, solder; 310, middle solder; 320, edge solder. DETAILED DESCRIPTION

[0031] As known from the background art, the grid line electrodes and the solder points of the BC battery are arranged on the back surface of the battery to completely avoid the grid line electrodes from being shielded on the front surface of the battery. In order to avoid the edge of the cell from being broken or cracked due to the pulling force or stress caused by the soldering with the solder strip, the solder points on the cell are usually designed away from the edge of the cell.

[0032] However, the design of the solder points away from the edge of the cell and the BC battery having two kinds of grid lines with different polarities on the back surface will cause the solder points with the same polarity as the edge position and the main grid to be unable to be arranged with the above two kinds of grid lines with different polarities, that is, a blank area appears between the solder points at the edge position and the main grid, and the coverage of the grid lines on the surface of the cell body cannot be further improved.

[0033] The back contact photovoltaic cell in the embodiment of the present application connects the short grid and the fine grid with the same polarity through the first connection line, avoids the short grid from being unable to be utilized due to being clamped between the main grid with different polarities and the solder, and improves the coverage of the grid lines on the surface of the cell body, thereby improving the collection efficiency of the carriers by the grid lines and the photoelectric conversion efficiency of the back contact photovoltaic cell. Since the length of the short grid is smaller than the length of the fine grid, the amount of carriers collected and transported by the short grid is also smaller than that of the fine grid. The width of the first connection line at the end close to the fine grid is greater than the width of the first connection line at the end close to the short grid. On the one hand, this structure has a guiding effect on the transmission of carriers, guiding the carriers to be transported from the short grid with a shorter length to the fine grid with a longer length, reducing the connection resistance between the fine grid and the short grid, improving the transportation efficiency of the carriers, and thereby improving the photoelectric conversion efficiency of the back contact photovoltaic cell. On the other hand, the amount of slurry required for forming the first connection line is reduced, so as to reduce the production cost of the back contact photovoltaic cell.

[0034] In the description of the embodiments of the present application, the technical terms "first", "second", and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise explicitly and specifically limited. Similarly, "multiple groups" means more than two groups (including two groups), and "multiple pieces" means more than two pieces (including two pieces).

[0035] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0036] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent: A exists, A and B exist, and B exists. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0037] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application. For example, if the device or element in the drawing is inverted, the element described as "below" or "under" or "lower" or "bottom" of the other element or feature will be oriented "above" or "top" of the other element or feature. Therefore, the term "below" can cover both upward and downward orientations depending on the context in which the term is used, which will be apparent to those skilled in the art. The material can be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptions used herein can be interpreted accordingly.

[0038] In the description of the embodiments of the present application, unless specifically defined and limited, the terms "mounting", "connected", "connection", "fixed", and the like are to be broadly understood, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be direct connection, can also be indirect connection through an intermediate medium, can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0039] In the corresponding drawings of the embodiments of the present application, the thickness and area of the layers are exaggerated for better understanding and ease of description. In addition, when describing that a component is "formed substantially" on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on a part of the edge of the entire surface.

[0040] In the description of the embodiments of the present application, when a certain component "includes" another component, unless otherwise stated, other components are not excluded, and other components can also be further included. The second component is formed or disposed above or on the first component, or is formed or disposed on the surface of the first component, or is formed or disposed on one side of the first component. It can include embodiments in which the first component and the second component are in direct contact, and can also include embodiments in which additional components can be between the first component and the second component, so that the first component and the second component can not be in direct contact. For simplicity and clarity, various components can be arbitrarily drawn in different proportions. In the drawings, some layers / components can be omitted for simplicity. As no specific description is given, the first component has a second component formed or disposed on the surface thereof, which means that the first component is in direct contact with the second component. Among them, the "component" mentioned above can refer to a layer, a film, a region, a part, a structure, etc.

[0041] The terms used in the description of various embodiments described herein are only used to describe specific embodiments, and are not intended to be limiting. As used in the description of various embodiments and the appended claims, "the component" is also intended to include the plural form, unless the context clearly indicates otherwise. Among them, the component includes layers, films, regions, or plates, etc.

[0042] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art can understand that in the embodiments of the present application, many technical details are proposed in order to enable the reader to better understand the present application. However, the technical solutions claimed by the present application can be realized even without these technical details and various changes and modifications based on the following embodiments.

[0043] Figure 1A structural schematic diagram of a back contact photovoltaic cell is shown.

[0044] Reference Figure 1 The back contact photovoltaic cell comprises:

[0045] The cell body 100 has a first direction X, a second direction Y and a third direction Z intersecting with each other; the cell body 100 has a first surface 110 and a second surface opposite to each other in the third direction Z; the first surface 110 has a pair of opposite first edges 1001 in the first direction X; and the third direction Z is the thickness direction of the cell body 100.

[0046] The soldering part 300 is arranged on the first surface 110; the soldering part 300 comprises an intermediate soldering part 310 and an edge soldering part 320, and the intermediate soldering part 310 is arranged between the pair of opposite edge soldering parts 320 in the first direction X.

[0047] The fine grid 220 is arranged on the first surface 110 and extends discontinuously along the first direction X; and a plurality of fine grids 220 are arranged in sequence and spaced apart along the second direction Y.

[0048] The short grid 230 is arranged on the first surface 110 and extends along the first direction X; and the short grid 230 is arranged between the first edge 1001 and the edge soldering part 320.

[0049] The first connecting line 240 extends along the second direction Y; the first connecting line 240 is arranged between the first edge 1001 and the edge soldering part 320; and the short grid 230 and the fine grid 220 of the same polarity adjacent to the short grid 230 are electrically connected through the first connecting line 240.

[0050] The width of one end of the first connecting line 240 close to the short grid 230 is smaller than the width of the other end.

[0051] The back contact photovoltaic cell in the embodiment of the present application connects the short grid 230 and the fine grid 220 with the same polarity through the first connecting line 240, avoids the short grid 230 from being unable to be utilized due to being clamped between the opposite main grid 210 and the welding part 300, improves the coverage of the grid line on the surface of the cell body 100, further improves the collection efficiency of the grid line to the carriers, and improves the photoelectric conversion efficiency of the back contact photovoltaic cell. Wherein, due to the length size of the short grid 230 being smaller than the length size of the fine grid 220, the amount of carriers collected and transported by the short grid 230 is also less than that of the fine grid 220, the width of the first connecting line 240 at the end close to the fine grid 220 is greater than the width of the first connecting line 240 at the end close to the short grid 230, on the one hand, the structure has a guiding effect on the transmission of the carriers, guiding the carriers to be transported from the short grid 230 with a shorter length to the fine grid 220 with a longer length, reducing the connection resistance between the fine grid 220 and the short grid 230, improving the transport efficiency of the carriers, and further improving the photoelectric conversion efficiency of the back contact photovoltaic cell, on the other hand, reducing the amount of slurry required to form the first connecting line 240, so as to reduce the production cost of the back contact photovoltaic cell.

[0052] It should be noted that the case where the first direction X and the second direction Y intersect includes: the first direction X and the second direction Y are perpendicular, or the included angle formed by the first direction X and the second direction Y is obtuse, or the included angle formed by the first direction X and the second direction Y is acute. In some examples, the included angle between the first direction X and the second direction Y can be 10°-90°, for example, 10°, 20°, 45°, 55°, 70°, 82° or 90°, etc. In some specific examples, the included angle between the first direction X and the second direction Y can also be 45°-90°. The case where the first direction X intersects the third direction Z and the case where the second direction Y intersects the third direction Z can refer to the corresponding description of the case where the first direction X and the second direction Y intersect, which will not be repeated here.

[0053] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings.

[0054] Referring to Figure 1 As shown in the figure, the back contact photovoltaic cell has intersecting and perpendicular first direction X, second direction Y and third direction Z, the positive electrode and the negative electrode of the back contact photovoltaic cell of the embodiment of the present application are both arranged on one side of the back light surface of the cell body, and the back contact photovoltaic cell comprises a cell body 100, a grid line and a welding part 300.

[0055] The cell body 100 is in a sheet structure, and the cell body 100 has a photoelectric effect. The grid line and the welding part 300 are both arranged on the first surface 110 of the cell body 100, and the first surface 110 is the back light surface of the cell body 100. In the first direction X, the cell body 100 has opposite first edges 1001 on both sides.

[0056] It should be noted that the back contact photovoltaic cell can be a single-sided cell, and the second surface of the cell body 100 can be regarded as the front surface of the back contact photovoltaic cell, and the second surface is a light-receiving surface for receiving incident light, and the first surface 110 is a back surface. Alternatively, the finally formed back contact photovoltaic cell can be a double-sided cell, and both sides of the cell body 100 can be used as light-receiving surfaces and can be used to receive incident light. It can be understood that the back surface described in the embodiments of the present application can also receive incident light, but the receiving degree of the back surface to the incident light is weaker than that of the light-receiving surface, and thus it is defined as the back surface.

[0057] In some embodiments, the cell body 100 can be divided from a whole cell sheet, i.e., the cell body 100 is N-pieces, and N is a positive integer greater than 1; in other embodiments, the cell body 100 can also be composed of a whole cell sheet, i.e., the cell body 100 is a whole piece.

[0058] In some embodiments, the cell body 100 is divided from a whole cell sheet, i.e., the cell body 100 is a two-piece (half piece).

[0059] In some embodiments, in the case where the cell body 100 is divided from a whole cell sheet, the grid lines and the soldering portion 300 are first formed on the first surface 110 of the whole cell sheet by a screen printing process, and then the whole cell sheet is divided into N-pieces of the cell body 100 in the embodiments of the present application to form the back contact photovoltaic cell in the embodiments of the present application. In other embodiments, the cell body 100 is a whole piece, i.e., the grid lines and the soldering portion 300 are formed on the first surface 110 of the cell body 100 by a screen printing process to directly form the back contact photovoltaic cell in the embodiments of the present application.

[0060] The grid lines are arranged on the first surface 110 of the cell body 100, and are used to collect and transmit photo-generated carriers to realize photoelectric conversion of the photovoltaic cell. Since the positive electrode and the negative electrode of the photovoltaic cell in the embodiments of the present application are arranged on the back surface of the cell body 100, the polarity of the grid lines can be one of the positive electrode or the negative electrode. The grid lines include fine grid lines 220, main grid lines 210, short grid lines 230, first connecting lines 240, and second connecting lines 250.

[0061] The main grid 210 extends along the second direction Y, and the main grids 210 with different polarities are alternately arranged along the first direction X. The fine grid 220 extends discontinuously along the first direction X, and a plurality of fine grids 220 are alternately arranged along the second direction Y. The fine grid 220 is connected to the main grid 210 with the same polarity, and the fine grid 220 is disconnected at the position of the main grid 210 with different polarity and the welding part 300, so as to ensure that the fine grid 220 with different polarity is insulated from the main grid 210 or the welding part 300, and to avoid short circuit and other problems. The main grid 210 includes an intermediate main grid 211 and an edge main grid 212, and the intermediate main grid 211 is arranged between a pair of edge main grids 212 opposite in the first direction X.

[0062] The welding part 300 is arranged on the first surface 110 of the battery piece body 100, and the welding part 300 is electrically connected to the main grid 210 or the fine grid 220. The welding part 300 is also welded to the solder strip in the photovoltaic module, so as to transmit the carriers collected and transmitted by the fine grid 220 and the main grid 210 to the external circuit through the solder strip.

[0063] The welding part 300 includes an intermediate welding part 310 and an edge welding part 320, and the intermediate welding part 310 is arranged between the edge welding parts 320 opposite in the first direction X. In other words, the edge welding part 320 is closer to the first edge 1001 opposite in the first direction X of the battery piece body 100 than the intermediate welding part 310. The intermediate welding part 310 is arranged at the position where the intermediate main grid 211 and the fine grid 220 are connected, and the edge welding part 320 is arranged at a distance from the edge main grid 212 in the first direction X. The edge welding part 320 and the edge main grid 212 are electrically connected through an edge connecting line 260. The edge connecting line 260 is a grid line clamped between the edge main grid 212 and the edge welding part 320, and the edge connecting line 260 extends along the first direction X. One end of the edge connecting line 260 is connected to the edge welding part 320, and the other end is connected to the edge main grid 212. The edge connecting line 260 is arranged in line with a fine grid 220. The edge welding part 320 is arranged at a distance from the edge main grid 212 in the first direction X, and the distance between the edge welding part 320 and the first edge 1001 in the first direction X is greater than the distance between the edge main grid 212 and the first edge 1001. The edge welding part 320 can be away from the first edge 1001, so as to avoid the welding stress or the tension of the solder strip on the battery piece body 100 caused by the welding connection between the edge welding part 320 and the solder strip, and to avoid the occurrence of the problems such as the fragmentation or the hidden crack of the battery piece body 100 at the edge position. The distance between the edge welding part 320 and the edge main grid 212 improves the yield and reliability of the back contact photovoltaic cell.

[0064] The grid line also includes a short grid 230 and a first connecting line 240. The short grid 230 is disposed between the edge welding portion 320 and the edge main grid 212, and extends along a first direction X. The first connecting line 240 extends along a second direction Y, and passes through the gap of the fine grid 220 with a different polarity to electrically connect the short grid 230 with the adjacent fine grid 220 of the same polarity. To ensure the welding quality of the edge welding portion 320 and its carrier transport efficiency, the edge welding portion 320 is usually large. When the edge welding portion 320 is large in the second direction Y, the fine grid 220 with the opposite polarity will break when it extends to the position of the edge welding portion 320, ensuring the insulation isolation between the fine grid 220 with the opposite polarity and the edge welding portion 320. In related technologies, no grid line structure with a different polarity is typically provided between the edge welding portion 320 and the edge main grid 212. However, this grid-free area prevents the grid line coverage on the surface of the cell body 100 from being further improved, thus hindering the improvement of the photoelectric conversion efficiency of the back-contact photovoltaic cell. In this embodiment, the short grid 230 is provided between the edge welding portion 320 and the edge main grid 212 with a different polarity, further improving the grid line coverage on the surface of the cell body 100, thereby improving the photoelectric conversion efficiency of the back-contact photovoltaic cell.

[0065] In some embodiments, the length of the short grid 230 is 1mm to 2mm. Optionally, the length of the short grid 230 is 1.2mm to 1.8mm, and the length of the short grid 230 can be 1.3mm, 1.4mm, 1.5mm, or 1.6mm. Setting the length of the short grid 230 to 1mm to 2mm ensures, on the one hand, that there is a certain distance between the edge welding part 320 and the edge main grid 212, avoiding the edge welding part 320 being too close to the first edge 1001, which could cause problems such as fragmentation or microcracks at the edge of the cell body 100. On the other hand, it avoids the short grid 230 being too short, resulting in a low capacity for collecting and transporting charge carriers. This would prevent the increased process cost of the first connecting line 240 for connecting the short grid 230 from being unbalanced with the increased light conversion efficiency of the back contact photovoltaic cell due to the short grid 230. This also avoids the short grid 230 and the first connecting line 240 being uncost-effective in terms of production cost.

[0066] Reference Figure 2 As shown, Figure 2 It shows Figure 1The enlarged structure schematic diagram at the middle A, the first connecting line 240 extends along the second direction Y, and the two ends of the second connecting line 250 are respectively in contact with the short grid 230 and the fine grid 220 with the same polarity. The width of the first connecting line 240 gradually increases in the extension direction thereof towards the fine grid 220 in contact therewith. In other words, the width of the first connecting line 240 near one end of the fine grid 220 in contact therewith is greater than that of the other end (i.e. the width of the first connecting line 240 near one end of the short grid 230 in contact therewith). The gradual change in the width of the first connecting line 240 reduces the connection resistance between the fine grid 220 and the short grid 230, improves the carrier transport efficiency, and thus improves the photoelectric conversion efficiency of the back contact photovoltaic cell, and on the other hand, reduces the amount of slurry required to form the first connecting line 240, thereby reducing the production cost of the back contact photovoltaic cell.

[0067] In some embodiments, the ratio between the width of the first connecting line 240 near one end of the fine grid 220 in contact therewith and the width of the other end (i.e. the width of the first connecting line 240 near one end of the short grid 230 in contact therewith) is 1-1.5. Optionally, the ratio between the width of the first connecting line 240 near one end of the fine grid 220 in contact therewith and the width of the other end (i.e. the width of the first connecting line 240 near one end of the short grid 230 in contact therewith) is 1.05-1.45, and the ratio between the width of the first connecting line 240 near one end of the fine grid 220 in contact therewith and the width of the other end (i.e. the width of the first connecting line 240 near one end of the short grid 230 in contact therewith) can be 1.1, 1.15, 1.2, 1.25, 1.3, 1.35 or 1.4.

[0068] In some embodiments, the width of the first connecting line 240 near one end of the fine grid 220 in contact therewith is 8-20 μm. Optionally, the width of the first connecting line 240 near one end of the fine grid 220 in contact therewith is 10-18 μm, and the width of the first connecting line 240 near one end of the fine grid 220 in contact therewith can be 12 μm, 14 μm, 15 μm or 16 μm.

[0069] In some embodiments, the width of the first connecting line 240 near one end of the short grid 230 in contact therewith is 8-15 μm. Optionally, the width of the first connecting line 240 near one end of the short grid 230 in contact therewith is 9-14 μm, and the width of the first connecting line 240 near one end of the short grid 230 in contact therewith can be 10 μm, 11 μm, 12 μm or 13 μm.

[0070] Further, the first connecting line 240 is in cross contact with the short grid 230 and / or the fine grid 220 to which the first connecting line 240 is in contact. In other words, the end of the first connecting line 240 connected with the short grid 230 or the fine grid 220 at least partially protrudes from the short grid 230 or the fine grid 220 in the second direction Y, i.e. the first connecting line 240 extends to the other side of the fine grid 220 to which the first connecting line 240 is in contact away from the short grid 230 to which the first connecting line 240 is in contact, and / or the first connecting line 240 extends to the other side of the short grid 230 to which the first connecting line 240 is in contact away from the fine grid 220 to which the first connecting line 240 is in contact. In other words, in the second direction Y, the distance between the end of the first connecting line 240 close to one of the short grid 230 or the fine grid 220 and the other of the short grid 230 or the fine grid 220 is greater than the distance between the short grid 230 and the fine grid 220. In other words, in the second direction Y, the length of the first connecting line 240 is greater than the distance between the short grid 230 and the fine grid 220. The design that the first connecting line 240 extends to the other side of the fine grid 220 or the short grid 230, on the one hand, avoids the non-lapping of the first connecting line 240 and the fine grid 220 or the short grid 230 due to the printing offset in the printing process, thereby causing the failure of the short grid 230 and the reduction of the photoelectric conversion efficiency of the back contact photovoltaic cell, and on the other hand, improves the lapping effect between the first connecting line 240 and the fine grid 220 or the short grid 230, reduces the connection resistance therebetween, and improves the transport capacity of the carriers.

[0071] In some embodiments, the length of the part of the first connecting line 240 extending to the other side of the fine grid 220 or the short grid 230 is 50 μm-130 μm. Optionally, the length of the part of the first connecting line 240 extending to the other side of the fine grid 220 or the short grid 230 is 60 μm-120 μm, and the length of the part of the first connecting line 240 extending to the other side of the fine grid 220 or the short grid 230 can be 70 μm, 80 μm, 90 μm or 100 μm.

[0072] Further, the first connecting line 240 and the fine grid 220 or the short grid 230 to which the first connecting line 240 is in contact are in a split structure, i.e. the fine grid 220 or the short grid 230 to which the first connecting line 240 is in contact is not formed synchronously with the first connecting line 240. Further, the first connecting line 240 is made of the same material as the main grid 210, and the first connecting line 240 is formed synchronously with the main grid 210 in the preparation process.

[0073] It should be noted that the printing direction is usually determined according to the structure with larger size in the printing process. For example, in the process of synchronously printing the first connecting line 240 and the main grid 210, the printing direction is usually along the extension direction of the main grid 210 (i.e. the second direction Y). For example, in the process of synchronously printing the first connecting line 240 and the fine grid 220, the printing direction is usually along the extension direction of the fine grid 220 (i.e. the first direction X). However, the intersection of the printing direction and the extension direction of the grid line will cause the risk of incomplete printing of the grid line or the short grid 230. The first connecting line 240 has the same extension direction as the main grid 210, and the first connecting line 240 is synchronously formed with the main grid 210 in the preparation process, which ensures that the printed shape of the first connecting line 240 is complete and continuous in the printing process, and avoids the risk of incomplete printing of the first connecting line 240 in the process of synchronously printing the first connecting line 240 with the fine grid 220 or the short grid 230, which may cause the first connecting line 240 to be not connected with the fine grid 220 or the short grid 230 or the grid to be broken, thereby improving the production yield of the back contact photovoltaic cell in the embodiment of the present application.

[0074] In combination with Figure 1 、 Figure 2 It is shown that the grid line further includes a second connecting line 250, the second connecting line 250 is arranged between the edge welding part 320 and the fine grid 220 with the same polarity and adjacent to each other, and the second connecting line 250 electrically connects the edge welding part 320 and the fine grid 220. The second connecting line 250 extends along the second direction Y, one end of the second connecting line 250 is in contact with the edge welding part 320, and the other end is in contact with the fine grid 220. The design of the first connecting line 240 causes a fine grid 220 adjacent to the edge welding part 320 to be broken at the position of the first connecting line 240, which causes the fine grid 220 to be unable to be directly electrically connected with the edge main grid 212. The second connecting line 250 electrically connects the fine grid 220 with the edge welding part 320, which on the one hand ensures that the carriers collected by the fine grid 220 can be transmitted to the edge welding part 320 through the second connecting line 250, and on the other hand, the fine grid 220 is directly electrically connected with the edge welding part 320 through the second connecting line 250, without the need to pass through other grid line structures such as the edge main grid 212, thereby shortening the transmission path of the carriers, reducing the internal resistance, improving the transportation efficiency of the carriers, and further improving the photoelectric conversion efficiency of the back contact photovoltaic cell.

[0075] Further, the width of the second connecting line 250 gradually increases along the extension direction of the second connecting line 250 towards the edge solder 320 to which the second connecting line 250 is in contact with. In other words, the width of the second connecting line 250 near one end of the edge solder 320 is greater than the width of the second connecting line 250 near the other end of the edge solder 320 (i.e. the end of the second connecting line 250 near the fine grid 220 to which the second connecting line 250 is in contact with). The gradual change in the width of the second connecting line 250 has the effect of guiding the transport of carriers from the fine grid 220 to the edge solder 320 to which the external circuit is electrically connected, thereby reducing the connection resistance between the fine grid 220 and the edge solder 320, improving the transport efficiency of the carriers, and further improving the photoelectric conversion efficiency of the back contact photovoltaic cell. On the other hand, the gradual change in the width of the second connecting line 250 reduces the amount of paste required to form the second connecting line 250, thereby reducing the production cost of the back contact photovoltaic cell.

[0076] In some embodiments, the ratio between the width of the second connecting line 250 near one end of the edge solder 320 to which the second connecting line 250 is in contact with and the width of the second connecting line 250 near the other end of the edge solder 320 (i.e. the end of the second connecting line 250 near the fine grid 220 to which the second connecting line 250 is in contact with) is 1-1.5. Alternatively, the ratio between the width of the second connecting line 250 near one end of the edge solder 320 to which the second connecting line 250 is in contact with and the width of the second connecting line 250 near the other end of the edge solder 320 (i.e. the end of the second connecting line 250 near the fine grid 220 to which the second connecting line 250 is in contact with) is 1.05-1.45. The ratio between the width of the second connecting line 250 near one end of the edge solder 320 to which the second connecting line 250 is in contact with and the width of the second connecting line 250 near the other end of the edge solder 320 (i.e. the end of the second connecting line 250 near the fine grid 220 to which the second connecting line 250 is in contact with) can be 1.1, 1.15, 1.2, 1.25, 1.3, 1.35 or 1.4.

[0077] In some embodiments, the width of the second connecting line 250 near one end of the edge solder 320 to which the second connecting line 250 is in contact with is 8-20 μm. Alternatively, the width of the second connecting line 250 near one end of the edge solder 320 to which the second connecting line 250 is in contact with is 10-18 μm. The width of the second connecting line 250 near one end of the edge solder 320 to which the second connecting line 250 is in contact with can be 12 μm, 14 μm, 15 μm or 16 μm.

[0078] In some embodiments, the width of the second connecting line 250 near one end of the fine grid 220 to which the second connecting line 250 is in contact with is 8-15 μm. Alternatively, the width of the second connecting line 250 near one end of the fine grid 220 to which the second connecting line 250 is in contact with is 9-14 μm. The width of the second connecting line 250 near one end of the fine grid 220 to which the second connecting line 250 is in contact with can be 10 μm, 11 μm, 12 μm or 13 μm.

[0079] Further, the second connecting line 250 is cross-contact connected with the fine grid 220 to which the second connecting line 250 is contact connected. In other words, the end of the second connecting line 250 connected with the fine grid 220 at least partially protrudes from the fine grid 220 in the second direction Y, that is, the second connecting line 250 extends to the other side of the fine grid 220 to which the second connecting line 250 is contact connected, away from the edge soldering portion 320. In other words, in the second direction Y, the distance between the end of the second connecting line 250 close to the fine grid 220 and the edge soldering portion 320 is greater than the distance between the edge soldering portion 320 and the fine grid 220. In other words, in the second direction Y, the length of the second connecting line 250 is greater than the distance between the edge soldering portion 320 and the fine grid 220. The design that the second connecting line 250 extends to the other side of the fine grid 220, on the one hand, avoids the non-lapping of the second connecting line 250 and the fine grid 220 due to the printing offset in the printing process, thereby causing the failure of the fine grid 220 and the reduction of the photoelectric conversion efficiency of the back-contact photovoltaic cell, and on the other hand, improves the lapping effect between the second connecting line 250 and the fine grid 220, reduces the connection resistance therebetween, and improves the carrier transport capacity.

[0080] In some embodiments, the length of the part of the second connecting line 250 extending to the other side of the fine grid 220 is 50 μm to 130 μm. Optionally, the length of the part of the second connecting line 250 extending to the other side of the fine grid 220 is 60 μm to 120 μm, and the length of the part of the second connecting line 250 extending to the other side of the fine grid 220 can be 70 μm, 80 μm, 90 μm or 100 μm.

[0081] Further, the second connecting line 250 and the edge soldering portion 320 are an integral structure, that is, the second connecting line 250 and the edge soldering portion 320 are synchronously formed in the preparation process.

[0082] It should be noted that the height of the welding portion 300 on the surface of the battery piece body 100 is generally higher than the height of the grid line on the surface of the battery piece body 100, on the one hand, in order to reduce the connection resistance between the welding portion 300 and the solder strip, and on the other hand, in order to ensure the welding connection effect between the welding portion 300 and the solder strip, and avoid other problems such as disconnection between the two. In the related art, the grid line and the welding portion 300 are usually printed in steps. For example, if the second connection line 250 in the embodiment of the present application is printed after the welding portion 300, in order to ensure the connection effect between the two, part of the second connection line 250 will be stacked on the surface of the edge welding portion 320, that is, the part of the second connection line 250 on the edge welding portion 320 will protrude from the surface of the edge welding portion 320. The edge welding portion 320 is welded and connected with the solder strip, and the solder strip will be stacked on the part of the second connection line 250, and the pressure exerted by the solder strip on the second connection line 250 and the thermal stress generated when the solder strip is welded and connected will cause the risk of disconnection of the second connection line 250. The second connection line 250 in the embodiment of the present application and the edge welding portion 320 are integrated structures, and the two are formed synchronously in the preparation process, the surfaces of the second connection line 250 and the edge welding portion 320 are flush, which avoids the situation that part of the second connection line 250 is stacked with the edge welding portion 320, and further avoids the problem of disconnection of the second connection line 250 caused by the extrusion of the solder strip or the welding thermal stress, thereby improving the reliability of the back contact photovoltaic cell in the embodiment of the present application.

[0083] With continued reference to Figure 2 As shown, the first surface 110 includes a main grid region 111 and a fine grid region 112. The main grid region 111 extends along the second direction Y, and the main grid regions 111 with different polarities are arranged alternately along the first direction X, and the main grid 210 is arranged in the main grid region 111 with the same polarity as the main grid 210. The fine grid region 112 extends discontinuously along the first direction X, and the fine grid regions 112 with different polarities are arranged alternately along the second direction Y, and the fine grid 220 is arranged in the fine grid region 112 with the same polarity as the fine grid 220. The fine grid region 112 is disconnected at the position of the main grid region 111.

[0084] The first surface 110 further includes a connection line region 113, and the connection line region 113 is arranged correspondingly to the first connection line 240. The connection line region 113 extends along the second direction Y, and the connection line region 113 is connected with the fine grid region 112 with the same polarity and adjacent to the connection line region 113. The fine grid region 112 is disconnected at the position of the connection line with different polarities.

[0085] In some embodiments, the ratio between the width of the connection line region 113 and the length of the short grid 230 in the first direction X is 0.5-1. Alternatively, the ratio between the width of the connection line region 113 and the length of the short grid 230 in the first direction X is 0.55-0.95, and the ratio between the width of the connection line region 113 and the length of the short grid 230 in the first direction X can be 0.6, 0.7, 0.8, or 0.9. It should be noted that an isolation region (not shown in the figure) is provided between adjacent regions with different polarities, and the isolation region insulates the regions with different polarities in the cell body 100. In the case where the width of the connection line region 113 in the first direction X is too small, the isolation regions on both sides of the connection line region 113 can not be formed completely due to process errors and other reasons, thereby causing the risk of short-circuit current between the connection line region 113 and the adjacent fine grid region 112 with different polarities. In the embodiment of the present application, the ratio between the width of the connection line region 113 and the length of the short grid 230 is set to 0.5-1, which on the one hand avoids the short-circuit current between the connection line region 113 and the adjacent fine grid region 112 with different polarities, and improves the open-circuit voltage and the fill factor of the back contact photovoltaic cell in the embodiment of the present application; and on the other hand ensures the insulation between the first connection line 240 provided in the connection line region 113 and the main grid 210 or the fine grid 220 adjacent thereto and having different polarities.

[0086] The first surface 110 further includes a solder region 114 corresponding to the solder 300, the solder 300 being arranged in the solder region 114 with the same polarity as the solder region 114, and the solder region 114 being connected to the fine grid region 112 with the same polarity as the solder region 114 in the second direction Y. The second connection line 250 is arranged in the solder region 114 or the fine grid region 112 with the same polarity as the solder region 114 or the fine grid region 112, i.e., the second connection line 250 at least partially passes through the solder region 114 and the fine grid region 112 to connect the edge solder 320 and the fine grid 220.

[0087] Correspondingly, another embodiment of the present application further provides a manufacturing method of a back contact photovoltaic cell, which can be used to manufacture the back contact photovoltaic cell provided in the above embodiments. The manufacturing method of the back contact photovoltaic cell provided in another embodiment of the present application will be described in detail below with reference to the accompanying drawings. The same or corresponding parts as those in the previous embodiment can be referred to the corresponding description of the previous embodiment, which will not be described in detail below.

[0088] Referring to Figure 3 illustrated, Figure 3 A step diagram of a manufacturing method of a back contact photovoltaic cell provided in an embodiment of the present application is shown, and the manufacturing method of the back contact photovoltaic cell includes:

[0089] Step S10, providing a battery piece body 100, the battery piece body 100 has opposite first and second surfaces 110 in the third direction Z; the battery piece body 100 has opposite first edges 1001 in the first direction X; the first direction X, the second direction Y and the third direction Z intersect, and the third direction Z is the thickness direction of the battery piece body 100.

[0090] Step S20, forming a plurality of welding portions 300 on the first surface 110, the welding portion 300 includes an intermediate welding portion 310 and an edge welding portion 320, the intermediate welding portion 310 is arranged between the opposite edge welding portions 320 in the first direction X.

[0091] Step S30, forming a first connecting line 240 on the first surface 110, the first connecting line 240 extends along the second direction Y. The first connecting line 240 is arranged on one side of the edge welding portion 320 close to the first edge 1001.

[0092] Step S40, forming a short grid 230 and a fine grid 220 on the first surface 110, the fine grid 220 extends along the first direction X, and a plurality of fine grids 220 are arranged in sequence and spaced apart along the second direction Y; the short grid 230 is arranged between the edge welding portion 320 and the first edge 1001; the first connecting line 240 is in contact with the fine grid 220 and the short grid 230; wherein the width of one end of the first connecting line 240 close to the short grid 230 is less than the width of the other end.

[0093] The preparation method of the back contact photovoltaic cell in the embodiment of the application connects the short grid 230 and the fine grid 220 with the same polarity through the first connecting line 240, avoids the short grid 230 from being unable to be utilized due to being arranged between the opposite main grid 210 and the welding portion 300, and improves the coverage of the grid line on the surface of the battery piece body 100, thereby improving the collection efficiency of the carrier by the grid line and the photoelectric conversion efficiency of the back contact photovoltaic cell. Since the length of the short grid 230 is smaller than the length of the fine grid 220, the amount of carriers collected and transported by the short grid 230 is also less than that of the fine grid 220. The width of one end of the first connecting line 240 close to the fine grid 220 is greater than the width of the other end close to the short grid 230. On the one hand, this structure has a guiding effect on the transmission of carriers, guiding the carriers to be transported from the short grid 230 with a shorter length to the fine grid 220 with a longer length, reducing the connection resistance between the fine grid 220 and the short grid 230, improving the transportation efficiency of the carriers, and thereby improving the photoelectric conversion efficiency of the back contact photovoltaic cell. On the other hand, the amount of slurry required for forming the first connecting line 240 is reduced, so as to reduce the production cost of the back contact photovoltaic cell.

[0094] Further, in the process of forming the first connecting line 240, the main grid 210 is formed on the first surface 110, the main grid 210 extends along the second direction Y, and a plurality of main grids 210 are sequentially and spaced apart along the first direction X. The fine grid 220 is in contact with the main grid 210 and / or the solder part 300 with the same polarity, and the fine grid 220 is disconnected at the position of the main grid 210 and / or the solder part 300 with different polarity. Wherein, the first connecting line 240 is formed synchronously with the main grid 210.

[0095] It should be noted that the first connecting line 240 has the same extension direction as the main grid 210, and the first connecting line 240 is formed synchronously with the main grid 210 in the preparation process, which ensures that the printed shape of the first connecting line 240 is complete and continuous in the printing process, avoids the incomplete printing of the first connecting line 240 in the process of being printed synchronously with the fine grid 220 or the short grid 230 intersecting with the extension direction of the first connecting line 240, and avoids the situation of not being connected with the fine grid 220 or the short grid 230 or the grid being disconnected due to incomplete printing, thereby improving the production yield of the back contact photovoltaic cell in the embodiment of the present application.

[0096] Further, the solder part 300 includes an intermediate solder part 310 and an edge solder part 320, and the intermediate solder part 310 is arranged between the edge solder parts 320 opposite in the first direction X. In the process of forming the solder part 300, the second connecting line 250 is formed on the first surface 110, the second connecting line 250 extends along the second direction Y, the second connecting line 250 is arranged between the edge solder part 320 and the fine grid 220 with the same polarity and adjacent, and the second connecting line 250 electrically connects the edge solder part 320 and the fine grid 220. Wherein, the second connecting line 250 is formed synchronously with the solder part 300, that is, the second connecting line 250 is formed synchronously with the edge solder part 320.

[0097] It should be noted that the second connecting line 250 is formed synchronously with the solder part 300 in the preparation process, and the surfaces of the second connecting line 250 and the edge solder part 320 are flush, avoiding the situation that part of the second connecting line 250 is stacked with the edge solder part 320, and further avoiding the problem of grid disconnection of the second connecting line 250 caused by the extrusion of the solder strip or the soldering thermal stress, thereby improving the reliability of the back contact photovoltaic cell in the embodiment of the present application.

[0098] In some embodiments, the width of the second connecting line 250 gradually increases in the extension direction of the edge solder part 320 which is in contact with the second connecting line 250. The gradual change in the width of the second connecting line 250 reduces the connection resistance between the fine grid 220 and the edge solder part 320, improves the transport efficiency of the carriers, and on the other hand, reduces the amount of paste required to form the second connecting line 250, thereby reducing the production cost of the back contact photovoltaic cell.

[0099] In some embodiments, the paste forming the first connecting line 240 is a non-burn-through paste, which avoids the first connecting line 240 from being misprinted in the printing process, resulting in an electrical connection between the first connecting line 240 and the doped layer of different polarity, and thus causing a short-circuit current and a decrease in the photoelectric conversion efficiency of the back contact photovoltaic cell.

[0100] In some embodiments, the paste forming the second connecting line 250 is a non-burn-through paste.

[0101] Correspondingly, another embodiment of the present application also provides a laminated cell, which comprises a back contact photovoltaic cell and a thin film cell laminated on one side of the back contact photovoltaic cell, the back contact photovoltaic cell serving as a bottom cell in the laminated cell, and the thin film cell serving as a top cell in the laminated cell, wherein the back contact photovoltaic cell is the back contact photovoltaic cell provided in the above-mentioned embodiment. The laminated cell provided in the second embodiment of the present application will be described in detail below, and the same or corresponding parts as the previous embodiment can refer to the corresponding description of the previous embodiment, which will not be described in detail below.

[0102] In some embodiments, the thin film cell comprises at least one of a perovskite thin film cell, a gallium arsenide thin film cell, a cadmium telluride thin film cell, and a copper indium gallium selenide thin film cell.

[0103] Correspondingly, another embodiment of the present application also provides a photovoltaic module, which comprises a cell string, an encapsulating adhesive film, and a cover plate. The cell string is formed by connecting a plurality of back contact photovoltaic cells or laminated cells, wherein the back contact photovoltaic cell is the back contact photovoltaic cell as described in the above-mentioned embodiment or obtained by the manufacturing method of the back contact photovoltaic cell as described in the above-mentioned embodiment, and the laminated cell is the laminated cell as described in the above-mentioned embodiment; the encapsulating adhesive film covers the surface of the back contact photovoltaic cell; and the cover plate is located on the surface of the encapsulating adhesive film away from the back contact photovoltaic cell. The same or corresponding parts as the previous embodiment can refer to the corresponding description of the previous embodiment, which will not be described in detail below.

[0104] The material of the encapsulating adhesive film can be an organic encapsulating adhesive film such as an ethylene-vinyl acetate copolymer film, a polyethylene octene elastomer film, or a polyvinyl butyral ester film.

[0105] The cover plate can be a glass cover plate, a plastic cover plate, or a cover plate having a light-transmitting function. In some embodiments, the surface of the cover plate facing the adhesive film can be a concave-convex surface, thereby increasing the utilization rate of incident light.

[0106] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A back contact photovoltaic cell, characterized by, The battery sheet comprises: a battery sheet body having a first direction, a second direction and a third direction intersecting with each other; the battery sheet body has opposite first and second surfaces in the third direction; the first surface has a pair of opposite first edges in the first direction; the third direction is the thickness direction of the battery sheet body; a welding portion is arranged on the first surface; the welding portion comprises an intermediate welding portion and edge welding portions arranged between the edge welding portions opposite in the first direction; a fine grid is arranged on the first surface, the fine grid extends discontinuously along the first direction, and a plurality of fine grids are arranged in sequence and spaced apart along the second direction; a short grid is arranged on the first surface, the short grid extends along the first direction, and the short grid is arranged between the first edge and the edge welding portion; a first connecting line extends along the second direction, the first connecting line is arranged between the first edge and the edge welding portion, and the short grid and the fine grid of the same polarity adjacent thereto are electrically connected by the first connecting line; wherein the width of one end of the first connecting line close to the short grid is smaller than the width of the other end.

2. The back contact photovoltaic cell of claim 1, wherein, The width of the first connecting line in the first direction gradually increases in the direction away from the short grid in contact therewith.

3. The back contact photovoltaic cell of claim 1, wherein, The ratio between the width of one end of the first connecting line close to the fine grid in contact therewith and the width of the other end of the first connecting line is 1-1.

5.

4. The back contact photovoltaic cell of claim 3, wherein, The width of one end of the first connecting line close to the fine grid in contact therewith is 8-20 μm, and the width of one end of the first connecting line close to the short grid in contact therewith is 8-15 μm.

5. The back contact photovoltaic cell of claim 1, wherein, The fine grid and / or the short grid in contact with the first connecting line are cross-connected, at least part of the first connecting line extends to one side of the fine grid away from the short grid, and / or at least part of the first connecting line extends to one side of the short grid away from the fine grid.

6. The back contact photovoltaic cell of claim 5, wherein, The length of the part of the first connecting line extending to the other side of the fine grid or the short grid is 50-130 μm.

7. The back contact photovoltaic cell of claim 1, wherein, Further comprising a main grid extending along the second direction, a plurality of main grids are arranged in sequence and spaced apart along the first direction; the fine grid is in contact with the main grid of the same polarity and / or the welding portion, and the fine grid is disconnected at the position of the main grid of different polarity and / or the welding portion; the main grid comprises an intermediate main grid and edge main grids arranged between a pair of edge main grids opposite in the first direction; wherein the edge main grid and the edge welding portion are electrically connected, and the edge main grid and the edge welding portion are arranged in a staggered manner in the first direction.

8. The back contact photovoltaic cell of claim 7, wherein, Further comprising a second connecting line, the fine grid adjacent to the edge welding portion and of the same polarity is in contact with the second connecting line; wherein the width of one end of the second connecting line close to the fine grid is smaller than the width of the other end.

9. The back contact photovoltaic cell of claim 8, wherein, The second connecting line has a width of 8-15 μm at one end close to the fine grid, and a width of 8-20 μm at one end close to the edge soldering part.

10. The back contact photovoltaic cell of claim 8, wherein, The second connecting line is cross-connected with the fine grid in contact therewith, and at least part of the second connecting line extends to the other side of the fine grid away from the edge soldering part.

11. The back contact photovoltaic cell of claim 10, wherein, The length of the part of the second connecting line extending to the other side of the fine grid is 50-130 μm.

12. The back contact photovoltaic cell of claim 8, wherein, The ratio between the width of the second connecting line at one end close to the edge soldering part in contact therewith and the width of the other end of the second connecting line is 1-1.

5.

13. The back contact photovoltaic cell of claim 8, wherein, The material of the first connecting line is the same as that of the main grid, and the first connecting line is in a split structure with the fine grid and / or the short grid. The edge soldering part in contact with the second connecting line is in an integral structure.

14. A method of fabricating a back contact photovoltaic cell, characterized by, The method comprises: providing a cell body having opposite first and second surfaces in a third direction; the cell body has opposite first edges in a first direction; the first direction, the second direction and the third direction intersect, and the third direction is the thickness direction of the cell body; forming a plurality of soldering parts on the first surface, the soldering parts comprising intermediate soldering parts and edge soldering parts, the intermediate soldering parts being arranged between the edge soldering parts opposite in the first direction; forming a first connecting line on the first surface, the first connecting line extending along the second direction; the first connecting line is arranged on one side of the edge soldering part close to the first edge; forming a short grid and a fine grid on the first surface, the fine grid extending along the first direction, and a plurality of the fine grids being arranged in sequence and spaced apart along the second direction; the short grid is arranged between the edge soldering part and the first edge; the first connecting line is in contact with the fine grid and the short grid; wherein the width of one end of the first connecting line close to the short grid is smaller than the width of the other end.

15. The method of claim 14, wherein the back contact photovoltaic cell is prepared by a process comprising: In the process of forming the first connecting line, a main grid is formed on the first surface, the main grid extending along the second direction, and a plurality of the main grids being arranged in sequence and spaced apart along the first direction; the fine grid is in contact with the main grid of the same polarity and / or the soldering part, and the fine grid is disconnected at the position of the main grid of different polarity and / or the soldering part; wherein the first connecting line and the main grid are formed synchronously.

16. A stacked battery characterized by comprising: The method comprises: a bottom cell, which is a back contact photovoltaic cell as claimed in any one of claims 1 to 13, or is formed by the preparation method of the back contact photovoltaic cell as claimed in any one of claims 14 or 15; a top cell, which is located on one side of the bottom cell.

17. A photovoltaic module, characterized by The method comprises: a cell string, which is connected by a plurality of back contact photovoltaic cells as claimed in any one of claims 1 to 13, or is connected by the back contact photovoltaic cells formed by the preparation method as claimed in any one of claims 14 or 15, or is connected by a plurality of laminated cells as claimed in claim 16. An encapsulation film for covering a surface of the battery string; A cover plate for covering a surface of the encapsulation film facing away from the battery string.

Images