Photovoltaic cell and preparation method thereof, laminated cell and photovoltaic module

Abstract

The embodiment of the invention relates to the field of photovoltaic cells, and provides a photovoltaic cell and a preparation method thereof, a laminated cell and a photovoltaic module, and the photovoltaic cell comprises a cell piece body which is provided with a first surface and a second surface which are opposite to each other; the multiple main grids are arranged on the first surface, extend in the second direction and are sequentially arranged at intervals in the first direction; the first direction intersects with the second direction; the fine grids are arranged on the first surface, extend in the first direction and are in contact connection with the main grids with the same polarity as the fine grids, and the fine grids are disconnected at the main grids with different polarities from the fine grids; the branch grids are arranged on the first surface, the branch grids are in contact connection with the fine grids with the same polarity as the branch grids, the branch grids with the same polarity are arranged at intervals in the first direction, the branch grids with different polarities are arranged at intervals in the second direction, and the extending direction of the branch grids intersects with the first direction. The photoelectric conversion efficiency can be improved at least.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic cells, in particular to a photovoltaic cell, a preparation method thereof, a stacked 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. The photovoltaic cell is a device for converting solar light energy into electrical energy. The photovoltaic cell uses the photovoltaic principle to generate carriers, and then uses the grid line to lead out the carriers, thereby facilitating the effective use of electrical energy. The grid line of the photovoltaic cell plays an important role in collecting and transmitting electrons. When a photovoltaic module is assembled by using multiple photovoltaic cells, a solder pad and / or a solder point are often arranged on the grid line, and then a solder strip is used to electrically contact the solder point to electrically connect the grid lines of adjacent photovoltaic cells.

[0003] To further avoid the shading of the grid line to the front surface of the photovoltaic cell, the research on the BC cell (Back Contact) is more and more in-depth. In the related technology, the N-type doped layer and the P-type doped layer in the BC cell are arranged alternately along the longitudinal direction, a thin grid extending in the transverse direction is arranged on a N-type or P-type doped layer, the doped layer is in contact with the thin grid in the thickness direction, the longitudinal main grid is in contact with the thin grid of the same polarity, and the solder pad is arranged on the main grid. The carriers in the doped layer are collected by the thin grid, and then transmitted to the external circuit through the thin grid, the main grid and the solder pad. SUMMARY

[0004] The present application provides a photovoltaic cell, a preparation method thereof, a stacked cell and a photovoltaic module, which at least solve the problem of low photoelectric conversion efficiency of the photovoltaic cell.

[0005] According to some embodiments of the present application, the present application provides a photovoltaic cell, which includes: a cell body having opposite first and second surfaces; a plurality of main grids arranged on the first surface, the main grids extending in a second direction, and the main grids being arranged in the first direction; the first direction and the second direction intersect; a plurality of thin grids arranged on the first surface, the thin grids extending in the first direction, the thin grids being in contact with the main grids of the same polarity, and the thin grids being disconnected at the main grids of different polarity; and a plurality of branch grids arranged on the first surface, the branch grids being in contact with the thin grids of the same polarity, the branch grids of the same polarity being arranged in the first direction, the branch grids of different polarity being arranged in the second direction, and the extension direction of the branch grids intersecting the first direction.

[0006] In some embodiments, the angle between the extension direction of the branch grid and the first direction is 30°-150°.

[0007] In some embodiments, a ratio between a length of the branch grid in the first direction and a width of the fine grid is 3-100.

[0008] In some embodiments, a length of the branch grid is 100-1000 μm; and / or a length of the branch grid in the first direction is 100-1000 μm.

[0009] In some embodiments, the first surface comprises fine grid regions arranged in sequence and spaced apart in the second direction, and first isolation regions arranged between adjacent fine grid regions; the fine grid regions extend discontinuously in the first direction; the fine grid is arranged in the fine grid regions; in the second direction, a ratio between a width of the fine grid region and a width of the first isolation region is 1-10.

[0010] In some embodiments, a width of the fine grid region is greater than a length of the branch grid in the first direction, and a difference between the width of the fine grid region and the length of the branch grid in the first direction is 10-100 μm.

[0011] In some embodiments, in the second direction, a size of the fine grid region is 100-1000 μm, and a size of the first isolation region is 10-1000 μm.

[0012] In some embodiments, a width of the fine grid is 1-30 μm; a width of the branch grid is 10-30 μm; in the first direction, a distance between adjacent branch grids is 100-1000 μm.

[0013] In some embodiments, a material of the main grid comprises at least one of copper particles or copper-coated silver particles; a material of the fine grid comprises at least one of copper particles or copper-coated silver particles; a material of the branch grid comprises silver particles.

[0014] In some embodiments, the main grid and the fine grid are in an integrated structure; or, the fine grid and the branch grid are in an integrated structure.

[0015] In some embodiments, the branch grid comprises a connecting portion and a contact portion, an extension direction of the connecting portion intersects an extension direction of the fine grid, the connecting portion is in contact with the fine grid of the same polarity, a plurality of the contact portions are arranged in sequence and spaced apart in the extension direction of the connecting portion, and a plurality of the contact portions are in contact with the connecting portion; wherein the contact portion is electrically connected with the battery piece body.

[0016] According to some embodiments of the present application, another aspect of the embodiments of the present application further provides a method for manufacturing a photovoltaic cell, comprising: providing a cell body, the cell body having opposite first and second surfaces in a thickness direction thereof; forming a plurality of main grids extending in a second direction on the first surface, the main grids being spaced apart in a first direction; the first direction and the second direction intersecting; forming a plurality of fine grids extending in the first direction on the first surface, the fine grids being connected to the main grids of the same polarity in contact, and the fine grids being disconnected at the main grids of different polarity; forming a plurality of branch grids extending in the second direction on the first surface, the branch grids of the same polarity being spaced apart in the first direction, and the branch grids of different polarity being spaced apart in the second direction; the branch grids being connected to the fine grids of the same polarity in contact; wherein the main grids and the fine grids are formed synchronously, or the fine grids and the branch grids are formed synchronously.

[0017] In some embodiments, in the case that the main grids and the fine grids are formed synchronously, the step of forming the main grids and the fine grids comprises: printing a first paste on the first surface by using a first screen printing process; and performing a curing process on the first paste to form the main grids and the fine grids; the step of forming the branch grids comprises: printing a second paste on the first surface by using a second screen printing process; and performing a sintering process on the second paste to form the branch grids; or, in the case that the fine grids and the branch grids are formed synchronously, the step of forming the main grids comprises: printing a first paste on the first surface by using a first screen printing process; and performing a curing process on the first paste to form the main grids; the step of forming the fine grids and the branch grids comprises: printing a second paste on the first surface by using a second screen printing process; and performing a sintering process on the second paste to form the fine grids and the branch grids; wherein the first paste is a non-punch-through paste, and the second paste is a punch-through paste.

[0018] In some embodiments, the first paste is a copper paste or a silver-coated copper paste, and the second paste is a silver paste.

[0019] According to some embodiments of the present application, another aspect of the embodiments of the present application further provides a method for manufacturing a photovoltaic cell, comprising: providing a cell body, the cell body having opposite first and second surfaces in the thickness direction thereof; forming main grids, fine grids and connecting portions on the first surface; a plurality of the main grids extend along a second direction; a plurality of the main grids are arranged along a first direction at intervals; the first direction and the second direction intersect; the fine grids extend along the first direction, the fine grids are connected to the main grids of the same polarity in contact, and the fine grids are disconnected at the main grids of different polarity; the connecting portions extend along the second direction, a plurality of the connecting portions of the same polarity are arranged along the first direction at intervals, and a plurality of the connecting portions of different polarity are arranged along the second direction at intervals; the connecting portions are connected to the fine grids of the same polarity in contact; forming contact portions on the first surface, a plurality of the contact portions are arranged along the extension direction of the connecting portions at intervals in sequence, the contact portions and the connecting portions are at least partially overlapped in the orthographic projection on the cell body, and a plurality of the contact portions are connected to the connecting portions in contact; the contact portions and the connecting portions are configured as support grids; wherein the main grids, the fine grids and the connecting portions are formed synchronously, and the contact portions are electrically connected to the cell body.

[0020] 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 photovoltaic cell as described above, or being a photovoltaic cell formed by a method for manufacturing a plurality of photovoltaic cells as described above; and a top cell, the top cell being located on one side of the bottom cell.

[0021] According to some embodiments of the present application, another aspect of the embodiments of the present application further provides a photovoltaic module, comprising: a cell string, the cell string being connected by a plurality of photovoltaic cells as described above, or being connected by a plurality of photovoltaic cells formed by a method for manufacturing a plurality of photovoltaic cells as described above, or being connected by a plurality of laminated cells as described above; an encapsulating adhesive film, the encapsulating adhesive film being used for covering the surface of the cell string; and a cover plate, the cover plate being used for covering the surface of the encapsulating adhesive film away from the cell string.

[0022] The technical solutions provided by the embodiments of the present application have at least the following advantages:

[0023] The embodiments of the present application provide a support grid connected to the fine grid, the support grid extending to a region farther from the fine grid connected thereto, so that the support grid has a lower conduction resistance between the edge region of the doped layer than the fine grid connected thereto, thereby improving the efficiency of collecting carriers and the photoelectric conversion efficiency of the photovoltaic cell. BRIEF DESCRIPTION OF DRAWINGS

[0024] One or more embodiments are illustrated by way of example in the drawings hereof, which are not intended to limit the embodiments of the present application, and for the purposes of simplifying the present application, proportions in the drawings are not necessarily in accordance with the scale, unless otherwise specified. In order to clearly illustrate the technical solutions in the embodiments of the present application or in the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor.

[0025] Figure 1 A structural schematic diagram of a photovoltaic cell provided for the first embodiment of the present application;

[0026] Figure 2 A structural schematic diagram of a photovoltaic cell provided for the first embodiment of the present application; Figure 1 An enlarged structural schematic diagram of A in the first embodiment of the present application;

[0027] Figure 3 A partial structural enlarged schematic diagram of a photovoltaic cell provided for the second embodiment of the present application;

[0028] Figure 4 A partial structural enlarged schematic diagram of a photovoltaic cell provided for the third embodiment of the present application;

[0029] Figure 5 A partial structural enlarged schematic diagram of a photovoltaic cell provided for the fourth embodiment of the present application;

[0030] Figure 6 A partial structural enlarged schematic diagram of a photovoltaic cell provided for the fifth embodiment of the present application.

[0031] Explanation of reference signs:

[0032] 100, cell body; 110, main grid area; 111, first main grid area; 112, second main grid area; 120, fine grid area; 121, first area; 122, second area; 130, isolation area; 131, first isolation area; 132, second isolation area; 200, main grid; 210, first main grid; 220, second main grid; 310, fine grid; 311, first fine grid; 312, second fine grid; 320, branch grid; 321, first branch grid; 322, second branch grid; 40, projection plane; 3201, branch grid projection; 3202, connecting part; 3203, contact part. DETAILED DESCRIPTION

[0033] As can be known from the background art, on the N-type or P-type doped layers arranged in the longitudinal direction in turn alternately, a fine grid is arranged on each doped layer to collect carriers. When the fine grid collects carriers, the conductive resistance of the area of the doped layer far from the fine grid is large, resulting in that the efficiency of the fine grid in collecting carriers in the edge area of the fine grid doped layer is low.

[0034] The present application provides a photovoltaic cell, a plurality of branch grids are arranged on the fine grid and connected with the fine grid, the branch grids extend to an area farther from the fine grid connected therewith, so that the branch grid has a lower conductive resistance between the branch grid and the edge area of the doped layer than the fine grid connected therewith, thereby improving the efficiency of collecting carriers and the photoelectric conversion efficiency of the photovoltaic cell.

[0035] In the description of the embodiments of the present application, the technical terms "first", "second", etc. 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 "a plurality of" is two or more, unless otherwise explicitly specified. Similarly, "a plurality of groups" means two or more groups (including two groups), and "a plurality of pieces" means two or more pieces (including two pieces).

[0036] In this paper, the phrase "embodiment" means that the specific features, structures or characteristics described in conjunction with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment that is not mutually exclusive with other embodiments. The skilled person explicitly and implicitly understands that the embodiments described herein can be combined with other embodiments.

[0037] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the existence of A, the existence of A and B, and the existence of B. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0038] In the description of the embodiments of the present application, the orientations or positional relationships indicated by the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like are based on the orientations or positional relationships shown in the drawings, and are merely for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply 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 devices or elements in the drawings are inverted, the elements described as being "below" or "under" or "lower" or "bottom" of other elements or features will be oriented "above" or "top" of the other elements or features. Therefore, the term "below" can encompass both upward and downward orientations depending on the context in which the term is used, which will be apparent to those of ordinary skill in the art. The materials can be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatially relative descriptions used herein can be interpreted accordingly.

[0039] In the description of the embodiments of the present application, unless explicitly specified and limited, the technical terms "mount", "connect", "connect", "fix", and the like should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrated; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill 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.

[0040] 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 it is described that one 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 is it formed on a part of the edge of the entire surface.

[0041] In the description of the embodiments of the present application, when a certain component "includes" another component, unless otherwise specified, other components are not excluded and can be further included. A second component formed or disposed above or on a first component, or formed or disposed on a surface of the first component, or formed or disposed on a side of the first component, can include an embodiment in which the first component and the second component are in direct contact, and can also include an embodiment in which additional components can be present 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, a second component formed or disposed on a surface of a first component 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.

[0042] The terms used in the description of various described embodiments herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of various described embodiments and the appended claims, "the component" is also intended to include the plural, unless the context clearly indicates otherwise. Among them, the component includes layers, films, regions, or plates, etc.

[0043] 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 implemented even without these technical details and various changes and modifications based on the following embodiments.

[0044] Figure 1 The structure schematic diagram of a photovoltaic cell provided by an embodiment of the present application.

[0045] Reference Figure 1 , the photovoltaic cell comprises:

[0046] The cell body 100 has opposite first and second surfaces;

[0047] The main grid 200 is arranged on the first surface, the main grid 200 extends along the second direction Y, and the main grid 200 is arranged in sequence along the first direction X; the first direction X and the second direction Y intersect;

[0048] The fine grid 310 is arranged on the first surface, the fine grid 310 extends along the first direction X, the fine grid 310 is connected in contact with the main grid 200 of the same polarity, and the fine grid 310 is disconnected at the main grid 200 of different polarity;

[0049] A plurality of support grids 320 are disposed on the first surface. The support grids 320 are in contact with the fine grids 310 of the same polarity. The plurality of support grids 320 of the same polarity are spaced apart along the first direction X. The plurality of support grids 320 of different polarities are spaced apart along the second direction Y. The extension direction of the support grids 320 intersects the first direction X.

[0050] In this embodiment, a branch gate 320 is provided on the fine gate 310 and connected to it. The branch gate extends to a region further away from the fine gate it is connected to, so that the branch gate has a lower conduction resistance with the edge region of the doped layer compared to the fine gate it is connected to, thereby improving the efficiency of collecting charge carriers and thus improving the photoelectric conversion efficiency of the photovoltaic cell.

[0051] The embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0052] Reference Figure 1 As shown, Figure 1 The diagram shows a schematic representation of a photovoltaic cell according to a first embodiment of this application. The photovoltaic cell includes: a cell body 100, a main grid 200, a fine grid 310, a side grid 320, and solder joints (not shown in the diagram). The main grid 200 and the fine grid 310 are used to collect and transport charge carriers. Solder joints are disposed on the main grid 200 or the fine grid 310, and are used for welding connections with solder strips and for transporting charge carriers to the solder strips.

[0053] In some embodiments, the photovoltaic cell is a BC cell, which can be an IBC cell (Interdigitated Back Contact), an HPBC cell (Hybrid Passivated Back Contact), a TBC cell that combines TOPCon (Tunnel Oxide Passivated Contact) technology and IBC technology, or an HBC cell that combines HIT / HJT (Heterojunction Technology) technology and IBC technology. Of course, it can also be other types of back contact photovoltaic cells.

[0054] In some embodiments, the photovoltaic cell type can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-component compound solar cell. Specifically, the multi-component compound solar cell can be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell.

[0055] The cell body 100 has intersecting and perpendicular first direction X, second direction Y, and third direction, the third direction being the thickness direction of the cell body 100. The cell body 100 has opposing first and second surfaces in the third direction. The main grid 200, fine grid 310, branch grid 320, and solder joints are disposed on the first surface of the cell body 100.

[0056] In some embodiments, the battery cell body 100 may be divided into 1 / N whole battery cells, that is, the battery cell body 100 is divided into N pieces, where N is a positive integer greater than 1; in other embodiments, the battery cell body 100 may also be composed of whole battery cells, that is, the battery cell body 100 is a whole piece.

[0057] In some examples, the cell body 100 is divided into 1 / 2 whole cells, that is, the cell body 100 is divided into two pieces.

[0058] It should be noted that the photovoltaic cell can be a single-sided cell, and the second surface can be considered as the front side of the back-contact photovoltaic cell, serving as the light-receiving surface for receiving incident light, while the first surface is the back-contact surface; alternatively, the final back-contact photovoltaic cell can be a bi-sided cell, in which case both the first and second surfaces can serve as light-receiving surfaces and can be used to receive incident light. It is understood that the back-contact surface described in the embodiments of this application can also receive incident light, but the degree of reception of incident light is weaker than that of the light-receiving surface, and therefore it is defined as a back-contact surface.

[0059] Combination Figure 1 , Figure 2 As shown, Figure 2 for Figure 1 The enlarged structural diagram at point A shows that the main grid 200 is disposed on the first surface of the cell body 100, the main grid 200 extends along the second direction Y, and several main grids 200 with different polarities are alternately and spaced along the first direction X.

[0060] In some embodiments, the main gate 200 includes a first main gate 210 and a second main gate 220 with different polarities. The first main gate 210 and the second main gate 220 extend along a second direction Y, and the first main gate 210 and the second main gate 220 are alternately arranged in a first direction X.

[0061] Fine grids 310 are disposed on the first surface of the cell body 100. Fine grids 310 extend along the first direction X. Several fine grids 310 with different polarities are alternately and spaced along the second direction Y. Fine grids 310 are cross-connected with main grids 200 with the same polarity. Fine grids 310 are disconnected at the position of main grids 200 with different polarities, so that fine grids 310 with different polarities and main grids 200 are insulated and isolated from each other.

[0062] In some embodiments, the fine grid 310 includes a first fine grid 311 and a second fine grid 312 with different polarities. The first fine grid 311 and the second fine grid 312 extend along the first direction X, and the first fine grid 311 and the second fine grid 312 are alternately arranged in sequence in the second direction Y. Among them, the first main grid 210 and the first fine grid 311 have the same polarity, the second main grid 220 and the second fine grid 312 have the same polarity. The first main grid 210 is one of the positive polarity or the negative polarity, and the second main grid 220 is the other of the positive polarity or the negative polarity. The first fine grid 311 and the second fine grid 312 extend to the position of the main grid 200 or the position in the extension direction of the main grid 200 and then break, so that the main grid 200 or the straight line where the main grid 200 is located passes through the break of the first fine grid 311 or the second fine grid 312. The first fine grid 311 breaks at the second main grid 220 with a different polarity from it, and the second fine grid 312 breaks at the first main grid 210 with a different polarity from it, to ensure insulation isolation between the fine grid 310 and the main grid 200 with different polarities, and avoid short - circuit caused by contact connection between the fine grid 310 and the main grid 200 with different polarities, thereby reducing the photoelectric conversion efficiency of the back - contact photovoltaic cell.

[0063] The branch grid 320 is arranged on the first surface of the cell body 100. The branch grid 320 is in contact connection with the fine grid 310 having the same polarity as it. A plurality of branch grids 320 with the same polarity are arranged at intervals in sequence along the first direction X, and a plurality of branch grids 320 with different polarities are arranged at intervals in the second direction Y. That is, a single fine grid 310 is in contact connection with multiple branch grids 320. The branch grid 320 extends in the direction away from the fine grid 310. A plurality of branch grids 320 in contact connection with the same fine grid 310 are arranged at intervals in sequence along the first direction X. The fine grid 310 and the branch grid 320 are configured into a structure similar to the Chinese character "丰". The extension direction of the branch grid 320 intersects with the first direction X.

[0064] The branch grid 320 extends to a more marginal position compared with the fine grid 310 it is connected to, so that there is a lower conduction resistance between the branch grid 320 and the edge area (the edge area is the edge position of the first area 121 or the second area 122, and the first area 121 and the second area 122 will be introduced below), to collect more carriers in the edge area, thereby improving the collection efficiency of carriers and the photoelectric conversion efficiency of the photovoltaic cell.

[0065] As Figure 2 shown, the extension direction of the branch grid 320 can be perpendicular to the first direction X, that is, the extension direction of the branch grid 320 is the second direction Y. As Figure 3 shown, Figure 3It is shown that the second embodiment of the present application provides a partial structure amplification schematic diagram of a photovoltaic cell. The extension direction of the branch grid 320 can also be arranged at an inclined angle with the first direction X. The extension directions of all branch grids 320 can be the same, or the branch grids 320 with different extension directions can be arranged according to actual needs. For example, the branch grids 320 with the same polarity have the same extension direction, and the branch grids 320 with different polarities have intersecting extension directions, which are not specifically limited here.

[0066] In some embodiments, the included angle between the extension direction of the branch grid 320 and the extension direction of the fine grid 310 (i.e. the first direction X) is 30°-150°. Optionally, the included angle between the extension direction of the branch grid 320 and the extension direction of the fine grid 310 is 45°-135°, and the included angle between the extension direction of the branch grid 320 and the extension direction of the fine grid 310 (i.e. the first direction X) can be 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120° or 130°. In the case where the included angle between the extension direction of the branch grid 320 and the extension direction of the fine grid 310 is 90°, i.e. the two extension directions are perpendicular, the amount of paste required for the branch grid 320 in a unit area is reduced, and the production cost is reduced. In the case where the included angle between the extension direction of the branch grid 320 and the extension direction of the fine grid 310 is an inclined angle, the overall length of the branch grid 320 in a unit area is increased, the collection efficiency of the branch grid 320 for carriers is improved, and the photoelectric conversion efficiency of the photovoltaic cell is further improved.

[0067] It should be further noted that the branch grid 320 with the same polarity and the fine grid 310 can be connected in contact (e.g. Figure 1 , Figure 2 ), or the end of the branch grid 320 close to the fine grid 310 can be connected in contact with the fine grid 310. As shown in Figure 4 , Figure 4 It is shown that the third embodiment of the present application provides a partial structure amplification schematic diagram of a photovoltaic cell. The branch grids 320 are symmetrically arranged on both sides of the fine grid 310 with respect to the first direction X, and the extension directions of the branch grids 320 intersect (i.e. fishbone type).

[0068] As shown in Figure 5 , Figure 5 It is shown that the fourth embodiment of the present application provides a partial structure amplification schematic diagram of a photovoltaic cell. The branch grids 320 are arranged on both sides of the fine grid 310 with respect to the first direction X and are alternately arranged in sequence along the first direction X. The above-mentioned branch grid 320 structure can be arranged according to actual needs. A single structure of branch grid 320 can be arranged on the same photovoltaic cell, or multiple structures of branch grid 320 can be arranged, which are not specifically limited here.

[0069] In some embodiments, the ratio between the length of the positive projection of the branch grid 320 along the first direction X and the width of the fine grid 310 is 3-100. Optionally, the ratio between the length of the projection of the branch grid 320 along the second direction Y and the width of the fine grid 310 is 5-90, and the ratio between the length of the positive projection of the branch grid 320 along the first direction X and the width of the fine grid 310 along the second direction Y can be 20, 40, 60 or 80. The ratio between the length of the positive projection of the branch grid 320 along the first direction X and the width of the fine grid 310 is adopted to be 3-100, so that the branch grid 320 is closer to the edge position of the fine grid area 120 than the fine grid 310, the collection capacity of the branch grid 320 for the carriers at the edge position of the fine grid area 120 is improved, and the photoelectric conversion efficiency of the photovoltaic cell is further improved.

[0070] It should be noted that the width of the fine grid 310 is the size of the fine grid 310 in the direction perpendicular to the first direction X, i.e., in the case where the first direction X and the second direction Y are perpendicular to each other, the width of the fine grid 310 is the size of the fine grid 310 along the second direction Y.

[0071] In some embodiments, the length of the positive projection of the branch grid 320 along the first direction X is 100-1000 μm. Optionally, the length of the projection of the branch grid 320 along the second direction Y is 200-900 μm, and the length of the projection of the branch grid 320 along the second direction Y can be 300 μm, 400 μm, 600 μm or 800 μm. The length of the positive projection of the branch grid 320 along the first direction X is set to be 100-1000 μm, on the one hand, the collection capacity of the branch grid 320 for the carriers at the edge position of the fine grid area 120 is improved, and on the other hand, the fine grid area 120 is adapted to increase its size along the second direction Y, the number of isolation areas 130 along the second direction Y of the same size cell body is reduced, the area ratio of the isolation area 130 on the cell body 100 is reduced, the area ratio of the fine grid area 120 on the cell body 100 is correspondingly increased, and the photoelectric conversion efficiency of the photovoltaic cell is further improved.

[0072] It should be noted that, as shown in Figure 2 and Figure 3 , the length of the positive projection of the branch grid 320 along the first direction X is the length of the branch grid projection 3201 of the branch grid 320 along the first direction X on the projection plane 40, wherein the projection plane is a plane perpendicular to the first direction X. That is, as shown in Figure 2 , in the case where the extension direction of the branch grid 320 is the second direction Y, the length of the positive projection of the branch grid 320 along the first direction X is equal to its own length; as shown in Figure 3 , in the case where the extension direction of the branch grid 320 and the extension direction of the fine grid 310 form an inclined angle, the length of the positive projection of the branch grid 320 along the first direction X is less than its own length. As shown in Figure 4 andFigure 5 As shown, the branch grating 320 is a split structure arranged on both sides of the fine grating 310 with respect to the first direction X, and the length of the branch grating 320 along the first direction X in the projection plane 40 is the total length of the branch grating projection 3201 of the branch grating 320 on both sides of the fine grating 310 along the first direction X in the projection plane 40, rather than the length of the branch grating projection 3201 of the branch grating 320 on one side of the fine grating 310 along the first direction X in the projection plane 40.

[0073] In some embodiments, the length of the branch grating 320 is 100 μm to 1000 μm. Alternatively, the length of the branch grating 320 is 200 μm to 900 μm, and the length of the branch grating 320 can be 300 μm, 400 μm, 600 μm, or 800 μm. The length of the branch grating 320 is set to 100 μm to 1000 μm, on the one hand to avoid the length of the branch grating 320 being too short to reduce the ability of the branch grating 320 to collect the carriers at the edge position of the fine grating area 120, and on the other hand to avoid the length of the branch grating 320 being too long to cause the internal resistance of the branch grating 320 to be too high, thereby reducing the transport capacity of the carriers.

[0074] In some embodiments, the width of the branch grating 320 is 1 μm to 30 μm. Alternatively, the width of the branch grating 320 is 2 μm to 28 μm, and the width of the branch grating 320 can be 10 μm, 15 μm, 20 μm, or 25 μm. The width of the branch grating 320 is set to 1 μm to 30 μm to balance the number of carriers collected and transported by the branch grating 320, to avoid the width of the branch grating 320 being too small to cause the internal resistance to be too high, or to avoid the width of the branch grating 320 being too large to cause the production cost to be too high, and the branch grating 320 to shield too much of the surface of the solar cell body 100 to reduce the photoelectric conversion efficiency of the photovoltaic cell.

[0075] In some embodiments, the width of the fine grating 310 is 1 μm to 30 μm. Alternatively, the length of the fine grating 310 is 2 μm to 28 μm, and the width of the fine grating 310 can be 10 μm, 15 μm, 20 μm, or 25 μm. The width of the fine grating 310 is set to 1 μm to 30 μm, on the one hand to avoid the width of the fine grating 310 being too small to cause the internal resistance to be too high and the transport efficiency of the carriers to be reduced, or to avoid the width of the fine grating 310 being too large to cause the production cost to be too high, and the fine grating 310 to shield too much of the surface of the solar cell body 100 to reduce the photoelectric conversion efficiency of the photovoltaic cell.

[0076] In some embodiments, the distance between the adjacent branch grids 320 is 100-1000 μm in the first direction X when the branch grids 320 are parallel to each other. Alternatively, the distance between the adjacent branch grids 320 is 200-9000 μm in the first direction X, and the distance between the adjacent branch grids 320 can be 400 μm, 500 μm, 600 μm or 800 μm. The distance between the adjacent branch grids 320 is kept in a proper range to achieve a balance between the amount of paste required for printing the branch grids 320 and the efficiency of the branch grids 320 in collecting carriers, and to achieve a balance between the production cost and the photoelectric conversion efficiency of the photovoltaic cell, so as to improve the photoelectric conversion efficiency of the photovoltaic cell without greatly increasing the production cost of the photovoltaic cell.

[0077] In some embodiments, the number of branch grids 320 arranged on the fine grid 310 between the adjacent main grids 200 is 5-15. Alternatively, the number of branch grids 320 arranged on the fine grid 310 between the adjacent main grids 200 is 7-13, and the number of branch grids 320 arranged on the fine grid 310 between the adjacent main grids 200 can be 8, 9, 10, 11 or 12.

[0078] It should be noted that the fine grid 310 between the adjacent main grids 200 is a part of the first fine grid 311 or the second fine grid 312 corresponding to the area between the adjacent first main grid 210 and the second main grid 220.

[0079] In some embodiments, the branch grid 320 includes a first branch grid 321 and a second branch grid 322, the first branch grid 321 has the same polarity as the first main grid 210 and the first fine grid 311, and the second branch grid 322 has the same polarity as the second main grid 220 and the second fine grid 312. The first branch grid 321 is connected to the first fine grid 311 in cross, and the second branch grid 322 is connected to the second fine grid 312 in cross. In the second direction Y, the first fine grid 311 and the second fine grid 312 are arranged in a spaced manner to avoid short circuit caused by connection.

[0080] In some embodiments, the material of the main grid 200 includes at least one of copper particles or copper-coated silver particles. The material of the fine grid 310 includes at least one of copper particles or copper-coated silver particles. The material of the branch grid 320 includes silver particles.

[0081] It should be noted that when the material of the fine grid 310 is the same as the material of the main grid 200, the fine grid 310 and the main grid 200 are an integrated structure, that is, the fine grid 310 and the main grid 200 are formed synchronously in the production process, and the paste for forming the fine grid 310 and the main grid 200 is a non-burn-through type paste. Compared with the burn-through type paste commonly used in the related art, the non-burn-through type paste has a lower silver content, so as to reduce the production cost.

[0082] It should also be noted that when the material of the fine grid 310 is the same as that of the support grid 320, the fine grid 310 and the support grid 320 are an integral structure, that is, the fine grid 310 and the support grid 320 are formed synchronously during the production process. The slurry that forms the fine grid 310 and the support grid 320 is a burn-through slurry. The fine grid 310 formed by the burn-through slurry is electrically connected to the doped layer in the cell body 100, so that the fine grid 310 has the function of collecting charge carriers, improving the collection efficiency of the photovoltaic cell for charge carriers, and thus improving the photoelectric conversion efficiency of the photovoltaic cell.

[0083] like Figure 6 As shown, Figure 6 The diagram shows a partial enlarged structural schematic of a photovoltaic cell according to the fifth embodiment of this application. In this embodiment, the grid 320 includes a connecting portion 3202 and a contact portion 3203 electrically connected to the cell body 100. A plurality of contact portions 3203 are arranged at intervals along the second direction Y. The connecting portion 3202 is a long strip structure extending along the second direction Y. The connecting portion 3202 is in contact with the plurality of contact portions 3203, and the orthographic projections of the connecting portion 3202 and the contact portions 3203 on the cell body 100 at least partially overlap.

[0084] In some embodiments, the connecting portion 3202 and the contact portion 3203 are made of different materials. This avoids the grid 320 being made of the same material. By adjusting the material costs of the connecting portion 3202 and the contact portion 3203, for example, designing the material cost of the connecting portion 3202 to be lower than that of the contact portion 3203, the required material usage can be reduced by using multiple dispersed contact portions 3203, thereby reducing the manufacturing cost of the photovoltaic cell. For example, the material forming the connecting portion 3202 is not a non-burn-through paste, while the material forming the contact portion 3203 is a burn-through paste. The silver content in the burn-through paste is higher than that in the non-burn-through paste. By reducing the material cost of the connecting portion 3202, the manufacturing cost of the photovoltaic cell can be reduced.

[0085] In some embodiments, the contact portion 3203 has a circular, elliptical, triangular, or rectangular shape. When the contact portion 3203 is circular, its diameter is 5 μm to 40 μm. When the contact portion 3203 is rectangular, its diagonal dimension is 15 μm to 100 μm.

[0086] In some embodiments, the area of ​​the contact portion 3203 is 100 μm. 2 ~5000μm 2 Optionally, the contact area 3203 has an area of ​​1000 μm. 2 ~4500μm 2 The contact area of ​​3203 can be 1500 μm.2 2000μm 2 3000μm 2 or 4000μm 2 .

[0087] In some embodiments, the distance between adjacent contact portions 3203 in the second direction Y is 10 μm to 100 μm. Optionally, the distance between adjacent contact portions 3203 in the second direction Y is 20 μm to 90 μm, and the distance between adjacent contact portions 3203 in the second direction Y can be 30 μm, 40 μm, 60 μm or 80 μm.

[0088] like Figure 2 As shown, the battery cell body 100 includes a plurality of main grid regions 110 arranged sequentially at intervals along a first direction X, and the main grid regions 110 extend along a second direction Y. The main grid regions 110 with different polarities are arranged alternately at intervals along the first direction X. Each main grid region 110 includes a first main grid region 111 and a second main grid region 112, which correspond to the first main grid 210 and the second main grid 220, respectively. The first main grid 210 is disposed in the first main grid region 111, and the second main grid 220 is disposed in the second main grid region 112.

[0089] The battery cell body 100 also includes fine grid regions 120 arranged at intervals along the second direction Y. The fine grid regions 120 extend along the first direction X. The fine grid regions 120 are in contact with the main grid regions 110 of the same polarity, and the fine grid regions 120 are disconnected at the positions of the main grid regions 110 of different polarities. In the first direction X, the fine grid regions 120 and the main grid regions 110 of different polarities are arranged at intervals to insulate them from each other, so as to avoid leakage or even short circuit due to contact between them.

[0090] The fine gate region 120 includes a first region 121 and a second region 122, which extend along a first direction X. A first fine gate 311 and a first branch gate 321 are disposed in the first region 121, and a second fine gate 312 and a second branch gate 322 are disposed in the second region 122. The first region 121 is interrupted at the position of the first main gate region 111, and the second region 122 is interrupted at the position of the second main gate region 112, so that the first fine gate 311 in the first region 121 is insulated from the second main gate region 112 where the second main gate 220 is located, and the second region 122 where the second fine gate 312 is located is insulated from the first main gate region 111 where the first main gate 210 is located.

[0091] The first region 121 and the first main grid region 111 correspond to a first doped layer (not shown in the figure) in the solar cell body 100, and the second region 122 and the second main grid region 112 correspond to a second doped layer (not shown in the figure) in the solar cell body 100. In some embodiments, the first fine grid 311 is in contact with the first doped layer, and the second fine grid 312 is in contact with the second doped layer. In other embodiments, the first fine grid 311 and the first branch grid 321 are both in contact with the first doped layer, and the second fine grid 312 and the second branch grid 322 are both in contact with the second doped layer.

[0092] In some embodiments, the doped elements in the first doped layer and the second doped layer are of different types, and the doped element in one of them is an N-type doped element, and the doped element in the other is a P-type doped element. The N-type doped element can be any one of a phosphorus (P) element, a bismuth (Bi) element, an antimony (Sb) element, or an arsenic (As) element, etc. The P-type semiconductor substrate is doped with a P-type element, and the P-type doped element can be any one of a boron (B) element, an aluminum (Al) element, a gallium (Ga) element, or an indium (In) element, etc.

[0093] In some embodiments, in the second direction Y, the length of the positive projection of the branch grid 320 along the first direction X is smaller than the width dimension of the fine grid region 120 in the second direction Y, and the difference between the width dimension of the fine grid region 120 in the second direction Y and the length of the positive projection of the branch grid 320 along the first direction X is 10 μm to 100 μm. Optionally, the difference between the width dimension of the fine grid region 120 in the second direction Y and the length of the positive projection of the branch grid 320 along the first direction X is 20 μm to 90 μm, and the difference between the width dimension of the fine grid region 120 in the second direction Y and the length of the positive projection of the branch grid 320 along the first direction X can be 40 μm, 50 μm, 60 μm, or 80 μm. If the length of the branch grid 320 is too long, the branch grid 320 will be misprinted in the second direction Y due to printing errors, and the branch grid 320 will be misprinted into the adjacent fine grid region 120 with different polarity. If the length of the branch grid 320 is too short, the collection efficiency of the branch grid 320 for the carriers in the corresponding fine grid region 120 will be low. By setting the ratio between the length of the positive projection of the branch grid 320 along the first direction X and the width dimension of the fine grid region 120 in the second direction Y within an appropriate range, the problems caused by the length of the branch grid 320 being too long or too short are avoided, the reliability of the product is improved, and the photoelectric conversion efficiency of the photovoltaic cell of the embodiments of the present application is improved.

[0094] In some embodiments, in the second direction Y, the width of the fine grid region 120 is 100 μm to 1000 μm. Optionally, the width of the fine grid region 120 is 200 μm to 900 μm, and the width of the fine grid region 120 can be 300 μm, 400 μm, 600 μm, or 800 μm.

[0095] With continued reference to Figure 2 As shown, the photovoltaic cell of the embodiments of the present application further includes an isolation region 130, which includes a first isolation region 131 and a second isolation region 132. The first isolation region 131 is arranged between adjacent fine grid regions 120 with different polarities, and the second isolation region 132 is arranged between the main grid region 110 and the fine grid region 120 with different polarities arranged at intervals in the second direction Y. The isolation region 130 corresponds to the isolation layer between the first doped layer and the second doped layer in the cell body 100, so as to ensure insulation between the first doped layer and the second doped layer, avoid contact between the two to generate leakage current, and even cause short circuit of the photovoltaic cell.

[0096] The arrangement of the branch grid 320 in the embodiments of the present application causes the size of the fine grid region 120 in the second direction Y to increase, so that the number of fine grid regions 120 in the embodiments of the present application is reduced compared with the number of fine grid regions in the related art on the same area of the cell, and the number of first isolation layers required between adjacent fine grid regions 120 with different polarities is also reduced, thereby reducing the area of the first isolation layer on the cell body 100, improving the area ratio of the main grid region 110 and the fine grid region 120 on the cell body 100, i.e., the area ratio of the first doped layer and the second doped layer on the cell body 100, and improving the photoelectric conversion efficiency of the photovoltaic cell in the embodiments of the present application.

[0097] In some embodiments, in the second direction Y, the ratio between the width of the fine grid region 120 and the width of the first isolation region 131 is 1 to 10. Optionally, the ratio between the width of the fine grid region 120 and the width of the first isolation region 131 is 2 to 9, and the ratio between the width of the fine grid region 120 and the width of the first isolation region 131 can be 4, 5, 6, or 7.

[0098] In some embodiments, in the second direction Y, the width of the first isolation region 131 is 10 μm to 1000 μm. Optionally, in the second direction Y, the width of the first isolation region 131 is 50 μm to 900 μm, and the width of the first isolation region 131 can be 200 μm, 400 μm, 600 μm, or 800 μm.

[0099] The embodiment of the present disclosure further provides a preparation method of a photovoltaic cell, which is used for preparing the photovoltaic cell provided in the first embodiment, the second embodiment, the third embodiment and the fourth embodiment. The preparation method of the photovoltaic cell provided in the second embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that the same or corresponding parts as those in the foregoing embodiments will not be described herein.

[0100] Referring to Figure 1 , Figure 2 As shown in the figure, the preparation method of the photovoltaic cell comprises the following steps: providing a cell piece body 100, which has opposite first and second surfaces in the thickness direction thereof. Forming a plurality of main grids 200 extending along the second direction Y on the first surface; the plurality of main grids 200 are arranged at intervals along the first direction X; the first direction X and the second direction Y intersect. Forming a plurality of fine grids 310 extending along the first direction X on the first surface, the fine grids 310 are connected in contact with the main grids 200 having the same polarity, and the fine grids 310 are disconnected at the main grids 200 having different polarities. Forming a plurality of branch grids 320 extending along the second direction Y on the first surface, the plurality of branch grids 320 having the same polarity are arranged at intervals along the first direction X, and the plurality of branch grids 320 having different polarities are arranged at intervals along the second direction Y; the branch grids 320 are connected in contact with the fine grids 310 having the same polarity. The main grids 200 and the fine grids 310 are formed synchronously, or the fine grids 310 and the branch grids 320 are formed synchronously.

[0101] In some embodiments, in the case that the main grids 200 and the fine grids 310 are formed synchronously, the step of forming the main grids 200 and the fine grids 310 comprises: printing a first paste on the first surface by using a first screen printing process; and performing a curing treatment on the first paste to form the main grids 200 and the fine grids 310. The step of forming the branch grids 320 comprises: printing a second paste on the first surface by using a second screen printing process; and performing a sintering treatment on the second paste to form the branch grids 320. The first paste is a non-sintering-through type paste, and the second paste is a sintering-through type paste. The silver content in the non-sintering-through type paste is lower than that in the sintering-through type paste, that is, the cost of the non-sintering-through type paste is lower than that of the sintering-through type paste. The fine grids 310 and the main grids 200 are synchronously printed and cured by using the non-sintering-through type paste, and the production cost of the fine grids 310 in the embodiment of the present disclosure is lower than that of the fine grids 310 formed by using the sintering-through type paste in the related art, thereby reducing the production cost of the photovoltaic cell.

[0102] It should be noted that, since the first paste is a non-sintering-through type paste and the second paste is a sintering-through type paste, the finally formed branch grids 320 will be connected in contact with the doped layer in the cell piece body 100, but the main grids 200 and the fine grids 310 are only located on the surface of the cell piece body 100, that is, they are not connected in contact with the doped layer, nor are they directly electrically connected with the cell piece body 100.

[0103] Further, in the case of synchronous formation of the main grid 200 and the fine grid 310, the width of the fine grid 310 is equal to the width of the main grid 200.

[0104] In some embodiments, in the case of synchronous formation of the fine grid 310 and the branch grid 320, the step of forming the main grid 200 includes: printing the first paste on the first surface by using a first screen printing process; and performing a curing treatment on the first paste to form the main grid 200; and the step of forming the fine grid 310 and the branch grid 320 includes: printing the second paste on the first surface by using a second screen printing process; and performing a sintering treatment on the second paste to form the fine grid 310 and the branch grid 320.

[0105] It should be noted that, since the first paste is a non-burn-through type paste and the second paste is a burn-through type paste, the finally formed branch grid 320 and fine grid 310 will be in contact with the doped layer in the battery piece body 100, but the main grid 200 is only located on the surface of the battery piece body 100, that is, it is not in contact with the doped layer and will not be directly electrically connected with the battery piece body 100.

[0106] The fine grid 310 and the branch grid 320 in the embodiment are synchronously printed and sintered by using the second paste which is a burn-through type paste, compared with the embodiment of the fine grid 310 formed by the first paste which is a non-burn-through type paste, the fine grid 310 in the embodiment will be in contact with the doped layer (the first doped layer or the second doped layer) in the battery piece body 100 after the sintering treatment, and the fine grid 310 can collect the carriers in the doped layer, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0107] Further, in the case of synchronous formation of the fine grid 310 and the branch grid 320, the width of the fine grid 310 is equal to the width of the branch grid 320.

[0108] In some embodiments, the method of performing the curing treatment on the first paste includes a thermal sintering process, a laser sintering process or a thermal curing process.

[0109] In some embodiments, the method of performing the sintering treatment on the second paste includes a thermal sintering process or a laser sintering process.

[0110] In some embodiments, the first paste is a copper paste or a silver-coated copper paste. In some embodiments, the second paste is a silver paste.

[0111] It should be noted that, in the case of the first paste being a copper paste or a silver-coated copper paste, the method of performing the curing treatment on the first paste is a thermal curing process.

[0112] Another embodiment of the present disclosure also provides a method for manufacturing a photovoltaic cell. The method for manufacturing the photovoltaic cell provided by the second embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that the same or similar parts as those of the previous embodiments will not be described herein.

[0113] Referring to Figure 6 As shown in FIG. 6, the method for manufacturing the photovoltaic cell includes: providing a cell body 100 having opposite first and second surfaces in the thickness direction of the cell body 100. The main grid 200, the fine grid 310 and the connecting part 3202 are formed on the first surface. The main grids 200 extend along the second direction. The main grids 200 are arranged along the first direction at intervals. The first direction intersects the second direction. The fine grid 310 extends along the first direction. The fine grid 310 is connected to the main grid 200 with the same polarity and is disconnected at the main grid 200 with the different polarity. The connecting part 3202 extends along the second direction. The connecting parts 3202 with the same polarity are arranged along the first direction at intervals. The connecting parts 3202 with the different polarity are arranged along the second direction at intervals. The connecting part 3202 is connected to the fine grid 310 with the same polarity. The contact part 3203 is formed on the first surface. The contact parts 3203 are arranged along the extension direction of the connecting part 3202 at intervals. The contact part 3203 and the connecting part 3202 at least partially overlap in the orthographic projection on the cell body 100. The contact part 3203 is connected to the connecting part 3202. The contact part 3203 and the connecting part 3202 form the support grid 320. The main grid 200, the fine grid 310 and the connecting part 3202 are formed synchronously. The contact part 3203 is electrically connected to the cell body 100.

[0114] In some embodiments, the step of forming the main grid 200, the fine grid 310 and the connecting part 3202 includes: printing a first paste on the first surface by using a first screen printing process; and curing the first paste to form the main grid 200, the fine grid 310 and the connecting part 3202. The step of forming the contact part 3203 includes: printing a second paste on the first surface by using a second screen printing process; and sintering the second paste to form the contact part 3203. The first paste is a non-burn-through paste, and the second paste is a burn-through paste. The silver content in the non-burn-through paste is lower than that in the burn-through paste, that is, the cost of the non-burn-through paste is lower than that of the burn-through paste. The main grid 200, the fine grid 310 and the connecting part 3202 are synchronously printed and cured by using the non-burn-through paste. The support grid 320 in the embodiment has a lower production cost, thereby reducing the production cost of the photovoltaic cell.

[0115] It should be noted that, since the first paste is a non-burn-through paste and the second paste is a burn-through paste, the finally formed connecting part 3202 will be in contact with the doped layer in the battery piece body 100, but the main grid 200, the fine grid 310 and the connecting part 3202 are only located on the surface of the battery piece body 100, that is, not in contact with the doped layer, and will not be directly electrically connected with the battery piece body 100.

[0116] Correspondingly, the second embodiment of the present application also provides a laminated battery, which comprises a photovoltaic cell and a thin film cell laminated on one side of the photovoltaic cell, the photovoltaic cell is used as a bottom cell in the laminated battery, and the thin film cell is used as a top cell in the laminated battery, wherein the photovoltaic cell is the photovoltaic cell provided in the above-mentioned embodiment. The laminated battery provided in the second embodiment of the present application will be described in detail below. The same or corresponding parts as the previous embodiment can refer to the corresponding description of the previous embodiment, and will not be described in detail hereinafter.

[0117] 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.

[0118] Correspondingly, the second 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 photovoltaic cells or laminated batteries, wherein the photovoltaic cell is as described above or obtained by the manufacturing method of the photovoltaic cell described above, and the laminated battery is as described above; the encapsulating adhesive film covers the surface of the photovoltaic cell; and the cover plate is located on the surface of the encapsulating adhesive film away from the photovoltaic cell. The same or corresponding parts as the previous embodiment can refer to the corresponding description of the previous embodiment, and will not be described in detail hereinafter.

[0119] The material of the encapsulating adhesive film can be an organic encapsulating adhesive film such as an ethylene-vinyl acetate copolymer adhesive film, a polyethylene octene copolymer elastomer adhesive film or a polyvinyl butyral ester adhesive film.

[0120] The cover plate can be a glass cover plate, a plastic cover plate or a cover plate with 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.

[0121] It can be understood by those skilled in the art that the above-mentioned embodiments are specific embodiments for implementing the present application, and in actual application, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make various modifications and changes without departing from the spirit and scope of the present application, therefore the protection scope of the present application should be limited by the scope defined in the claims.

Claims

1. A photovoltaic cell, characterized in that, include: A battery cell body having opposing first and second surfaces; A plurality of main gates are disposed on the first surface, the main gates extend along a second direction, and the plurality of main gates are arranged at intervals along a first direction; the first direction and the second direction intersect. A plurality of fine grids are disposed on the first surface, the fine grids extend along the first direction, the fine grids are in contact with the main grids having the same polarity therewith, and the fine grids are disconnected at the main grids having different polarities therewith; A plurality of the support grids are disposed on the first surface. Each support grid is in contact with a fine grid of the same polarity. The plurality of support grids of the same polarity are spaced apart along the first direction, and the plurality of support grids of different polarities are spaced apart along the second direction. The extension direction of the support grids intersects the first direction.

2. The photovoltaic cell according to claim 1, characterized in that, The angle between the extension direction of the support grid and the first direction is 30° to 150°.

3. The photovoltaic cell according to claim 1 or 2, characterized in that, The ratio between the orthographic projection length of the support grid along the first direction and the width of the fine grid is 3 to 100.

4. The photovoltaic cell according to claim 3, characterized in that, The length of the support grid is 100μm to 1000μm, and / or the orthographic projection length of the support grid along the first direction is 100μm to 1000μm.

5. The photovoltaic cell according to claim 1, characterized in that, The first surface includes fine gate regions arranged sequentially at intervals along the second direction, and a first isolation region disposed between adjacent fine gate regions; the fine gate regions extend discontinuously along the first direction; the fine gates are disposed within the fine gate regions; In the second direction, the ratio between the width of the fine gate region and the width of the first isolation region is 1 to 10.

6. The photovoltaic cell according to claim 5, characterized in that, In the second direction, the width of the fine grid region is greater than the orthographic projection length of the support grid along the first direction, and the difference between the width of the fine grid region and the orthographic projection of the support grid along the first direction is 10 μm to 100 μm.

7. The photovoltaic cell according to claim 5, characterized in that, In the second direction, the size of the fine gate region is 100μm to 1000μm, and the size of the first isolation region is 10μm to 1000μm.

8. The photovoltaic cell according to claim 1, characterized in that, The width of the fine grid is 1μm to 30μm; The width of the support grid is 1μm to 30μm; In the first direction, the distance between adjacent support grids is 100 μm to 1000 μm.

9. The photovoltaic cell according to claim 1, characterized in that, The main grid material includes at least one of copper particles or copper-plated silver particles; The material of the fine grid includes at least one of copper particles or copper-coated silver particles; The support grid is made of silver particles.

10. The photovoltaic cell according to claim 1, characterized in that, The main grid and the fine grid are an integral structure; Alternatively, the fine grid and the support grid may be an integral structure.

11. The photovoltaic cell according to claim 1, characterized in that, The support grid includes a connecting portion and a contact portion. The extending direction of the connecting portion intersects with the extending direction of the fine grid. The connecting portion and the fine grid with the same polarity are in contact connection. A plurality of contact portions are arranged sequentially at intervals along the extending direction of the connecting portion. A plurality of contact portions are in contact connection with the connecting portion. The contact portion is electrically connected to the battery cell body.

12. A method for preparing a photovoltaic cell, characterized in that, include: A battery cell body is provided, the battery cell body having opposing first and second surfaces in its thickness direction; A plurality of main grids extending along a second direction are formed on the first surface; the plurality of main grids are arranged at intervals along the first direction; The first direction and the second direction intersect; A plurality of fine grids extending along a first direction are formed on the first surface, the fine grids are in contact with the main grids with the same polarity, and the fine grids are disconnected at the main grids with different polarities. A plurality of branch grids extending along a second direction are formed on the first surface; a plurality of branch grids with the same polarity are spaced apart along a first direction; a plurality of branch grids with different polarities are spaced apart along the second direction; the branch grids are in contact with the fine grids with the same polarity. The main gate and the fine gate are formed simultaneously, or the fine gate and the branch gate are formed simultaneously.

13. The method for preparing a photovoltaic cell according to claim 12, characterized in that, When the main gate and the fine gate are formed synchronously, the steps for forming the main gate and the fine gate include: A first screen printing process is used to print a first paste on the first surface; the first paste is then cured to form the main grid and the fine grid. The step of forming the support grid includes: printing a second paste on the first surface using a second screen printing process; and sintering the second paste to form the support grid. Alternatively, if the fine grid and the branch grid are formed simultaneously, the step of forming the main grid includes: A first screen printing process is used to print a first paste on the first surface; the first paste is then cured to form the main grid. The steps of forming the fine grid and the branch grid include: printing a second paste on the first surface using a second screen printing process; and sintering the second paste to form the fine grid and the branch grid. The first slurry is a non-burn-through slurry, and the second slurry is a burn-through slurry.

14. The method for preparing a photovoltaic cell according to claim 13, characterized in that, The first paste is copper paste or silver-coated copper paste, and the second paste is silver paste.

15. A method for preparing a photovoltaic cell, characterized in that, A battery cell body is provided, the battery cell body having opposing first and second surfaces in its thickness direction; Main grids, fine grids, and connecting portions are formed on the first surface; a plurality of the main grids extend along a second direction; A plurality of main gates are arranged at intervals along a first direction; the first direction and the second direction intersect; a fine gate extends along the first direction, and the fine gate is in contact with the main gate with the same polarity, and the fine gate is disconnected at the main gate with the different polarity; a connecting portion extends along the second direction, a plurality of connecting portions with the same polarity are arranged at intervals along the first direction, and a plurality of connecting portions with different polarities are arranged at intervals along the second direction; the connecting portion is in contact with the fine gate with the same polarity; A contact portion is formed on the first surface, and a plurality of the contact portions are arranged at intervals along the extending direction of the connecting portion. The orthographic projections of the contact portions and the connecting portion on the battery cell body at least partially overlap, and a plurality of the contact portions are in contact with the connecting portion. The contact portions and the connecting portion are configured to form a support grid. The main grid, the fine grid, and the connecting portion are formed simultaneously, and the contact portion is electrically connected to the battery cell body.

16. A stacked battery, characterized in that, include: The bottom cell is a photovoltaic cell as described in any one of claims 1 to 11, or a photovoltaic cell formed by a plurality of methods for preparing photovoltaic cells as described in any one of claims 12 to 15; A top battery, located on one side of the bottom battery.

17. A photovoltaic module, characterized in that, include: A battery string is formed by connecting multiple photovoltaic cells as described in any one of claims 1 to 11, or by connecting multiple photovoltaic cells formed by the method of preparing photovoltaic cells as described in any one of claims 12 to 15, or by connecting multiple stacked cells as described in claim 16; An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

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