CN117936606A

CN117936606A - Solar cell and photovoltaic module

Info

Publication number: CN117936606A
Application number: CN202410330837.6A
Authority: CN
Inventors: 夏志鹏; 王巍; 黄纪德; 刘长明; 张昕宇; 金浩
Original assignee: Jinko Solar Haining Co Ltd
Current assignee: Jinko Solar Haining Co Ltd
Priority date: 2024-03-21
Filing date: 2024-03-21
Publication date: 2024-04-26

Abstract

The embodiment of the application relates to the technical field of photovoltaics, and provides a solar cell and a photovoltaic module. The solar cell includes: a substrate having a first surface; the first surface is provided with a first doping part and a second doping part, the first doping part comprises a first part and a second part, the doping concentration of the second part is larger than that of the first part, and the second doping part comprises a plurality of third parts; the first fine grid comprises a plurality of first sub-fine grids, the second fine grid comprises a plurality of second sub-fine grids, at least part of the first sub-fine grids are positioned on corresponding first parts, two adjacent first sub-fine grids are connected through the second parts, and at least part of the second sub-fine grids are positioned on corresponding third parts; the first main grid and the second main grid, at least part of the second main grid is located above a row of second parts arranged along the first direction, the first main grid is connected with the first sub-fine grid, and the second main grid is connected with the second sub-fine grid. The embodiment of the application is at least beneficial to improving the performance of the solar cell.

Description

Solar cell and photovoltaic module

Technical Field

The embodiment of the application relates to the technical field of photovoltaics, in particular to a solar cell and a photovoltaic module.

Background

Currently, with the gradual depletion of fossil energy, solar cells are increasingly used as new energy alternatives. A solar cell is a device that converts solar light energy into electrical energy. The solar cell generates carriers by using a photovoltaic principle, and then the carriers are extracted by using electrodes, thereby effectively utilizing electric energy.

An IBC battery (crossed back electrode contact battery, INTERDIGITATED BACK CONTACT) is a back junction back contact solar battery structure in which positive and negative metal electrodes are arranged on the back surface of the battery in an interdigital mode, the IBC battery is one of photovoltaic batteries with highest conversion efficiency at present, the battery takes monocrystalline silicon as a matrix, p-n junctions and metal electrodes are all positioned on the back surface of the battery, and the front surface is not shielded by the metal electrodes, so that very high short circuit current and conversion efficiency can be obtained. However, the performance of IBC cells remains to be improved.

Disclosure of Invention

The embodiment of the application provides a solar cell and a photovoltaic module, which are at least beneficial to improving the performance of the solar cell.

In one aspect, an embodiment of the present application provides a solar cell, including: a substrate having a first surface; the first surface is provided with first doped parts and second doped parts which are alternately arranged along a first direction, the first doped parts are different from the second doped parts in conductivity type, the first doped parts comprise first parts and second parts which are alternately arranged along a second direction, the doping concentration of the second parts is larger than that of the first parts, the second doped parts comprise a plurality of third parts which are alternately arranged along the second direction, and the first direction is intersected with the second direction; an insulating layer, the insulating layer being located on the first surface; the thin grids penetrate through the insulating layer along the thickness direction of the insulating layer, the thin grids comprise first thin grids and second thin grids which are alternately arranged along the first direction, the first thin grids comprise a plurality of first sub-thin grids which are alternately arranged along the second direction, the second thin grids comprise a plurality of second sub-thin grids which are alternately arranged along the second direction, at least part of the first sub-thin grids are positioned on the corresponding first parts, two adjacent first sub-thin grids along the second direction are connected through the corresponding second parts, and at least part of the second sub-thin grids are positioned on the corresponding third parts; first main grids and second main grids which extend along the first direction and are alternately arranged along the second direction, the first main grids and the second main grids are positioned on the insulating layer along the thickness direction of the insulating layer, at least part of the second main grids are positioned above a row of second parts which are arranged along the first direction, the first main grids are connected with the first sub-fine grids, and the second main grids are connected with the second sub-fine grids.

In another aspect, an embodiment of the present application further provides a photovoltaic module, including: a cell string formed by connecting a plurality of solar cells as described in the above embodiments; a connection member for electrically connecting adjacent two solar cells; the packaging adhesive film is used for covering the surface of the battery string; and the cover plate is used for covering the surface, deviating from the battery string, of the packaging adhesive film.

The technical scheme provided by the embodiment of the application has at least the following advantages: in the solar cell, the first surface of the substrate comprises first doped parts and second doped parts which are alternately distributed along a first direction, the first doped parts comprise first parts and second parts which are alternately distributed along a second direction, a second main grid with different conductivity types from the first doped parts is positioned above a row of second parts which are distributed along the first direction, an insulating layer is arranged between the second main grid and the second parts, the insulating layer is used as a passivation layer, passivation is carried out on the back surface of a cell sheet, insulating isolation is carried out on the second main grid and the second parts, so that the first parts positioned on two sides of the second main grid along the second direction are connected through the second parts with higher doping concentration positioned below the second main grid, when the cell performance in one side area of the second main grid along the second direction is uneven or abnormal, the cell performance in the other side area of the second main grid along the second direction is different from the cell performance in the side area, the cell performance in the same type of the other side area of the second main grid is avoided, the cell performance in the other side area is not balanced, and further, the cell (Electro Luminescence) is prevented from being provided with different electroluminescent areas. In addition, along the thickness direction of insulating layer, first sub-thin bars are located the top of first part, along the second direction, adjacent first sub-thin bars are connected through the second part, and first main bars are connected with a row of first thin bars of arranging along first direction, so, along the thickness direction of insulating layer, the connection can all be realized through first main bars or the higher second part of doping concentration to the mutually independent first sub-thin bars that lie in first surface, the battery performance inhomogeneous that the mutual independence of first sub-thin bars led to and the mismatch phenomenon that local abnormality led to have been reduced.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, which are not to be construed as limiting the embodiments unless specifically indicated otherwise; in order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the drawings required for the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

Fig. 1 is a schematic structural diagram of a doped region on the back of a solar cell according to the related art;

Fig. 2 is a schematic structural diagram of a back surface of a solar cell according to the related art;

Fig. 3 is a schematic top view of a first surface of a solar cell according to some embodiments of the present application;

Fig. 4 is a schematic structural diagram of a back surface of a solar cell according to some embodiments of the present application;

fig. 5 is a schematic structural diagram of a back grid line of a solar cell according to some embodiments of the present application;

FIG. 6 is a partial cross-sectional view of a solar cell including a first sub-fine grid according to some embodiments of the present application;

FIG. 7 is a partial cross-sectional view of a solar cell including a second sub-fine grid according to some embodiments of the present application;

FIG. 8 is a schematic top view of a first surface of another solar cell according to some embodiments of the present application;

FIG. 9 is a schematic view of the back side of another solar cell according to some embodiments of the present application;

Fig. 10 is a schematic structural diagram of a back grid line of another solar cell according to some embodiments of the present application;

FIG. 11 is a partial cross-sectional view of another solar cell including a second sub-fine grid provided in accordance with some embodiments of the present application;

fig. 12 is a schematic view of a structure of a back grid line of another solar cell according to some embodiments of the present application;

FIG. 13 is a schematic top view of a first surface of a solar cell according to some embodiments of the present application;

Fig. 14 is a schematic partial perspective view of a photovoltaic module according to some embodiments of the present application.

Detailed Description

As used herein, features (e.g., regions, structures, devices) described as being "adjacent" to each other are intended to mean and include features having one or more of the disclosed identifiers positioned closest (e.g., closest) to each other. One or more additional features (e.g., additional regions, additional structures, additional devices) of the disclosed identification that do not match "adjacent" features may be disposed between the "adjacent" features. In other words, the "adjacent" features may be positioned directly adjacent to each other such that no other features are interposed between the "adjacent" features; or "adjacent" features may be positioned indirectly adjacent to each other such that at least one feature having an identification other than the identification associated with the at least one "adjacent" feature is positioned between the "adjacent" features.

In the following description, an embodiment in which a second member is formed or provided over or on a first member, or a second member is formed or provided on a surface of the first member, or a second member is formed or provided on one side of the first member may be included, and an embodiment in which the first member and the second member are in direct contact may be included, and an embodiment in which additional members may be included between the first member and the second member, so that the first member and the second member may not be in direct contact may be included. The various components may be arbitrarily drawn for simplicity and clarity. In the drawings, some layers/components may be omitted for simplicity.

Unless otherwise specified, the formation or disposition of a second component on the surface of a first component means that the first component is in direct contact with the second component.

Where the above-described "component" may refer to a layer, film, region, portion, structure, etc.

Moreover, for ease of description, relative terms such as "below …," "below …," "lower," "above …," "upper," and the like may be used herein to describe one element or component's relationship to another element(s) or component(s) as illustrated. Apart from the orientations shown in the figures, the relative terms are intended to include different orientations of the device in use or operation. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spacing used herein is similarly explained with respect to the descriptors. In the following embodiments, the terms "upper", "above …" and/or "over" are defined along a direction of increasing distance from the front and rear surfaces. Materials, configurations, dimensions, processes and/or operations as illustrated in the embodiments may be adopted in other embodiments, and detailed descriptions thereof may be omitted.

Spatially relative terms, such as "below," "lower," "bottom," "above," "upper," "top," "front," "back," "left," "right," and the like, as used herein, may be used for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. Unless otherwise specified, spatially relative terms are intended to encompass different orientations of the material in addition to the orientation depicted in the figures. For example, if the material in the illustrations is inverted, elements described as "below" or "beneath" or "lower" or "bottom" other elements or features would then be oriented "above" or "top" the other elements or features. Thus, the term "below" may depend on both the orientation above and below the upper and lower Wen Han covers where the term is used, as will be apparent to one of ordinary skill in the art. The material may be otherwise oriented (e.g., rotated 90 degrees, inverted, flipped) and the spatially relative descriptors used herein interpreted accordingly.

Unless otherwise apparent from the context, the term connection and its various forms as used herein, e.g., connection (connect, connected, connection) and the like, may refer to electrical connections.

As known from the background art, the photoelectric conversion efficiency and the structure of the IBC battery need to be improved.

Fig. 1 is a schematic structural diagram of a doped region on the back of a solar cell according to the related art; fig. 2 is a schematic structural diagram of a back surface of a solar cell according to the related art.

Referring to fig. 1 and 2, in the design of the back electrode pattern of the present back contact solar cell, a thin gate is generally used to connect the main gate with the same polarity, and the thin gate is disconnected at the opposite main gate, for example, the thin gate 15 of the positive electrode is disconnected at the main gate 14 of the negative electrode, the thin gate 13 of the negative electrode is disconnected at the main gate 16 of the positive electrode, the back surface of the corresponding substrate includes the P-type doped region 11 and the N-type doped region 12, the thin gate 15 of the positive electrode and the main gate 16 of the positive electrode are located on the corresponding P-type doped region 11, the thin gate 13 of the negative electrode and the main gate 14 of the negative electrode are located on the corresponding N-type doped region 12, the P-type doped regions 11 corresponding to the different main gates 16 of the positive electrode are independent from each other, the N-doped regions 12 corresponding to the different negative main gates 14 are independent of each other, and the thin gates corresponding to the different main gates are also independent of each other, for example, the N-doped regions 12 located at two sides of the dotted line are in a state of being disconnected from each other, and the negative thin gate 13 and the negative main gate 14 located at two sides of the dotted line are also in a state of being disconnected from each other, in such a design, a whole back contact solar cell is divided into a plurality of strip-shaped independent cell regions 10 which are hardly connected, and uneven or local abnormality of the cell performance may cause the different independent cell regions 10 to have different brightness in the subsequent EL test, resulting in component mismatch, and reduced component power.

In order to solve the above problems, in the solar cell, the first portions located at two sides of the second main grid are connected along the second direction by the second portions located under the second main grid and having higher doping concentration, so that when the cell performance in the regions at two sides of the second main grid along the second direction is uneven or local abnormality occurs in the cell in the region at one side, the resulting cell regions at two sides of the second main grid have different brightness and darkness in the EL test, which is beneficial to reducing the component mismatch and improving the component power. In addition, the mutually independent first sub-fine grids on the first surface can be connected through the first main grid or the second part with higher doping concentration, and compared with the state that the first sub-fine grids are mutually independent, the mutually connected first sub-fine grids reduce the mismatching phenomenon of different areas on the battery piece caused by uneven battery performance or local abnormality, and are beneficial to further reducing component mismatching and further improving component power.

Embodiments of the present application will be described in detail below with reference to the attached drawings. However, it will be understood by those of ordinary skill in the art that in various embodiments of the present application, numerous specific details are set forth in order to provide a thorough understanding of the present application. The claimed application may be practiced without these specific details and with various changes and modifications based on the following embodiments.

Fig. 3 is a schematic top view of a first surface of a solar cell according to some embodiments of the present application; fig. 4 is a schematic structural diagram of a back surface of a solar cell according to some embodiments of the present application; fig. 5 is a schematic structural diagram of a back grid line of a solar cell according to some embodiments of the present application; FIG. 6 is a partial cross-sectional view of a solar cell including a first sub-fine grid according to some embodiments of the present application; FIG. 7 is a partial cross-sectional view of a solar cell including a second sub-fine grid according to some embodiments of the present application; FIG. 8 is a schematic top view of a first surface of another solar cell according to some embodiments of the present application; FIG. 9 is a schematic view of the back side of another solar cell according to some embodiments of the present application; fig. 10 is a schematic structural diagram of a back grid line of another solar cell according to some embodiments of the present application; fig. 11 is a partial cross-sectional view of another solar cell including a second sub-fine grid according to some embodiments of the present application.

Referring to fig. 3 to 11, the solar cell includes: a substrate 100, the substrate 100 having a first surface 101; the first surface 101 has first doped portions 110 and second doped portions 120 alternately arranged along a first direction Y, the first doped portions 110 being different from the second doped portions 120 in conductivity type, the first doped portions 110 including first portions 112 and second portions 111 alternately arranged along a second direction X, the second portions 111 having a doping concentration greater than that of the first portions 112, the second doped portions 120 including a plurality of third portions 122 alternately arranged along the second direction X, the first direction Y intersecting the second direction X; an insulating layer 141, the insulating layer 141 being located on the first surface 101; a plurality of fine gratings positioned on the first surface 101, the fine gratings penetrating the insulating layer 141 in a thickness direction of the insulating layer 141, the fine gratings including first fine gratings and second fine gratings alternately arranged in a first direction Y, the first fine gratings including a plurality of first sub-fine gratings 140 spaced apart in a second direction X, the second fine gratings including a plurality of second sub-fine gratings 150 spaced apart in the second direction X, at least a portion of the first sub-fine gratings 140 being positioned on the respective first portions 112, two adjacent first sub-fine gratings 140 being connected by the respective second portions 111 in the second direction X, at least a portion of the second sub-fine gratings 150 being positioned on the respective third portions 122; the first and second main gates 170 and 160 extending in the first direction Y and alternately arranged in the second direction X are located on the insulating layer 141 in the thickness direction of the insulating layer 141, at least a portion of the second main gates 160 are located above a row of the second portions 111 arranged in the first direction Y, the first main gate 170 is connected to the first sub-fine gate 140, and the second main gate 160 is connected to the second sub-fine gate 150.

The first portions 112 located at two sides of the second main gate 160 along the second direction X are connected through the second portion 111 located under the second main gate 160 and having higher doping concentration, so that when the battery performance in the two side regions of the second main gate 160 along the second direction X is uneven or the battery in one side region is abnormal locally, the battery regions at two sides of the second main gate 160 have different brightness and darkness in the EL test, which is beneficial to reducing component mismatch and improving component power. In addition, the first sub-fine grids 140 that are independent of each other and located on the first surface 101 can be connected through the first main grid 170 or the second portion 111 with higher doping concentration, compared with the state that the first sub-fine grids 140 are independent of each other, the first sub-fine grids 140 that are connected with each other reduce the mismatch phenomenon of different areas on the battery piece caused by uneven battery performance or local abnormality, which is beneficial to further reducing component mismatch and further improving component power.

In some embodiments, the solar cell is a back contact solar cell, which refers to a solar cell in which electrodes of different polarities (first and second fine grids) are all located on the back side of the substrate 100.

In some embodiments, the material of the substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, which may be silicon or germanium, for example. The elemental semiconductor material may be in a single crystal state, a polycrystalline state, an amorphous state, or a microcrystalline state (a state having both a single crystal state and an amorphous state, referred to as a microcrystalline state), and for example, silicon may be at least one of single crystal silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

In some embodiments, the material of the substrate 100 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenium, and the like. The substrate 100 may also be a sapphire substrate, a silicon-on-insulator substrate, or a germanium-on-insulator substrate.

In some embodiments, the substrate 100 may be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, which may be any of v group elements such As phosphorus (P) element, bismuth (Bi) element, antimony (Sb) element, and arsenic (As) element. The P-type semiconductor substrate is doped with a P-type doping element, which may be any one of group III elements such as boron (B) element, aluminum (Al) element, gallium (Ga) element, and indium (In) element.

In some embodiments, referring to fig. 6, 7 and 11, in the thickness direction of the substrate 100, that is, in the third direction Z, the substrate 100 has a first surface 101 and a second surface 102 disposed opposite to each other, where the first surface 101 of the substrate 100 may be a back surface, and the second surface 102 may be a front surface, the front surface may be a light receiving surface for receiving incident light, and the back surface may be a backlight surface. The backlight surface can also receive the incident light, but the efficiency of receiving the incident light is weaker than that of the light receiving surface.

It should be noted that, the incident light received by the light receiving surface is directly irradiated on the solar cell by the sunlight, and the incident light received by the backlight surface is caused by the reflection of the ground, the reflection of another object, and the refraction of the film layer on the substrate 100.

In some embodiments, the second surface 102 of the substrate 100 has a textured structure, which may include regular shaped pyramid-shaped textured structures as well as irregularly shaped black silicon. The inclined surface of the suede structure can increase internal reflection of incident light, so that the absorption and utilization rate of the substrate 100 to the incident light are improved, and the cell efficiency of the solar cell is further improved.

In some embodiments, the second surface 102 of the substrate 100 has a front surface field (not shown) with the same conductivity type as the doping ions of the substrate 100, and the field passivation effect is used to reduce the surface minority carrier concentration, thereby reducing the surface recombination rate, and also reducing the series resistance and improving the electron transport capability.

In some embodiments, a solar cell includes: front passivation layer 180 is located on second surface 102, front passivation layer 180 being considered a front passivation layer. In some embodiments, the front passivation layer 180 may be a single layer structure or a stacked layer structure. In some embodiments, the material of the front passivation layer 180 may include one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

In some embodiments, the first surface 101 may be a polished surface, where the polished surface refers to a flat surface formed by removing the textured structure of the surface by polishing solution or laser etching. The flatness of the back surface after polishing is increased, the reflection of long-wave light is increased, and the secondary absorption of incident light is promoted, so that the short-circuit current is improved, meanwhile, the back surface recombination is reduced due to the reduction of the specific surface area of the back surface, and the passivation effect of the back surface can be improved.

Referring to fig. 4 and 9, the first surface 101 has first doping parts 110 and second doping parts 120 alternately arranged in the first direction Y, and the conductivity type of the first doping parts 110 is different from that of the second doping parts 120. The first doping part 110 may be one of a P-type doping region and an N-type doping region, and the second doping part 120 may be the other of the P-type doping region and the N-type doping region.

The first doping parts 110 and the second doping parts 120 are alternately distributed along the first direction Y, so that the N-type doping regions and the P-type doping regions of the first surface 101 are alternately and uniformly distributed, the existence of the large-area N-type doping regions or P-type doping regions is avoided, further, carriers are prevented from being collected by corresponding grid lines through long-distance transmission, the composite loss caused by long-distance transmission is reduced, the short-circuit current is favorably increased, the series resistance is reduced, the filling factor is improved, and the photoelectric conversion performance of the solar cell is improved.

In some embodiments, the first doping part 110 may be doped with doping ions of the same conductivity type as the substrate 100, and the second doping part 120 may be doped with doping ions of a different conductivity type than the substrate 100. For example, the substrate 100 is an N-type substrate, the first doped portion 110 is an N-type doped region, the second doped portion 120 is a P-type doped region, and a PN junction is formed between the second doped portion 120 and the remaining substrate 100 except for the second doped portion 120, so as to effectively shunt carriers.

In some embodiments, the doping concentration of the doping ions in the first doping portion 110 is greater than the doping concentration of the doping ions in the substrate 100, and a high-low junction is formed between the first doping portion 110 and the substrate 100 to enhance the separation capability of carriers. In other embodiments, the second doped portion 120 may be doped with dopant ions of the same conductivity type as the substrate 100, and the first doped portion 110 may be doped with dopant ions of a different conductivity type than the substrate 100.

A gap (gap) or an isolation structure (not shown) is provided between the first doped portion 110 and the second doped portion 120 to realize automatic isolation between regions of different conductivity types, so that the problem that the efficiency of the battery is affected due to leakage caused by formation of a tunnel junction between the heavily doped P-type doped region and the heavily doped N-type doped region on the back of the IBC battery can be avoided.

In some embodiments, the solar cell includes a passivation contact (PASSIVATED CONTACT) structure, which is described below as an example in which the first doped portion is doped with dopant ions of the same conductivity type as the substrate 100, and the second doped portion is doped with dopant ions of a different conductivity type than the substrate 100.

In some embodiments, the first doped portion has a first passivation contact structure, the first passivation contact structure includes a first tunneling layer and a first doped conductive layer, wherein the first tunneling layer is located between the substrate and the first doped portion, the first doped portion serves as the first doped conductive layer, doped ions of a same conductivity type as the substrate are doped in the first doped conductive layer, and a doping element concentration in the first doped conductive layer is greater than a doping element concentration of the substrate. The first passivation contact structure provides good surface passivation, and the first tunneling layer can enable majority carriers to tunnel into the first doped conductive layer and simultaneously block minority carrier recombination, so that the majority carriers are transversely transmitted in the first doped conductive layer and collected by the metal electrode, metal contact recombination current is greatly reduced, and open-circuit voltage and short-circuit current of the solar cell are improved.

In some embodiments, the material of the first tunneling layer may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

In some embodiments, the material of the second doped conductive layer may include at least one of amorphous silicon, polysilicon, or silicon carbide.

In some embodiments, the second doped portion has a second passivation contact structure, the second passivation contact structure includes a second tunneling layer and a second doped conductive layer, the second doped portion includes a second doped body, a second tunneling layer, and a second doped conductive layer sequentially arranged along a direction away from the substrate, the second doped body and the second doped conductive layer each have a doping ion of a different conductivity type than the substrate, and a doping element concentration in the second doped conductive layer is greater than a doping element concentration of the second doped body. The second passivation contact structure provides good surface passivation, and the second tunneling layer can enable majority carriers to tunnel into the second doped conductive layer and simultaneously block minority carrier recombination, so that the majority carriers are transversely transmitted in the second doped conductive layer and collected by the metal electrode, metal contact recombination current is greatly reduced, and open-circuit voltage and short-circuit current of the solar cell are improved.

In some embodiments, the material of the second tunneling layer may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

It should be noted that in practical application, the first doped portion and the second doped portion may both have corresponding passivation contact structures; or one of the first doped portion and the second doped portion has a respective passivation contact structure, and the other of the first doped portion and the second doped portion does not have a respective passivation contact structure; or neither the first doped portion nor the second doped portion has a passivation contact structure.

Referring to fig. 3, fig. 4, fig. 8 and fig. 9, the first doping parts 110 extend along the second direction X, and the first doping parts 110 include first portions 112 and second portions 111 alternately arranged along the second direction X, the doping concentration of the second portions 111 is greater than that of the first portions 112, in the second direction X, two adjacent first portions 112 are connected through one second portion 111, the first doping parts 110 are a whole doping area extending along the second direction X, at least part of the first sub-fine grids 140 are located on the corresponding first portions 112, two mutually independent first sub-fine grids 140 adjacent along the second direction X are connected through the second portions 111, so that when the battery performance of a battery area corresponding to different first portions 112 is uneven or an abnormality occurs in a certain battery area, any one first portion 112 can be connected with at least one adjacent first portion 112 through the second portion 111, the first sub-fine grids 140 corresponding to the first portion 112 can be connected with at least one other adjacent first portion through the second portion 111, the first sub-fine grids corresponding to the second portion 112 can be connected with the other first portion 112 through the second portion 111, the mutual performance of the first sub-fine grids can be improved, and the mutual performance of the first sub-fine grids can be improved, the mutual performance of the first sub-fine grids can be better than the adjacent fine grids can be better than the first sub-fine grids can be better compared, and the second fine grids can have mutual fine grids.

It should be noted that the substrate 100 has two edges opposite to each other along the second direction X, and the first doping portions 110 located at the outermost sides near the edges are the first portions 112.

Referring to fig. 3, 4, 8 and 9, the first portion 112 and the second portion 111 have the same conductivity type. If the first portion 112 is an N-type doped region, the second portion 111 is an N-type doped region, and the doping concentration of the second portion 111 is greater than that of the first portion 112. If the first portion 112 is a P-type doped region, the second portion 111 is a P-type doped region, and the doping concentration of the second portion 111 is greater than that of the first portion 112. The greater benefit of setting the doping concentration of the second portion 111 is that: the carrier transmission is performed between two adjacent first sub-fine grids 140 along the second direction X through the second portion 111, and the second portion 111 with larger doping concentration has better carrier transmission capability, so that the resistance is reduced, the recombination loss in the carrier transmission process is reduced, and further the photoelectric conversion efficiency of the solar cell is improved.

Referring to fig. 6, 7 and 11, an insulating layer 141 is located on the first surface 101, and the insulating layer 141 is used as a passivation layer. In some embodiments, the passivation layer may include a single layer film structure or a stacked layer film structure. In some embodiments, the material of the passivation layer may be any one or more of materials including silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

Referring to fig. 3, 5, 8 and 10, the arrangement of the back grid lines of the solar cell is as follows: the gate line includes a plurality of thin gates penetrating the insulating layer 141 in a thickness direction of the insulating layer 141, and includes a plurality of main gates located on a portion of the insulating layer 141 and a portion of the thin gates, the thin gates including first thin gates and second thin gates having different polarities, the first thin gates and the second thin gates being alternately arranged in a first direction Y, the first thin gates and the second thin gates each extending in a second direction X, the main gates including first main gates 170 and second main gates 160 alternately arranged in the second direction X, the polarities of the first main gates 170 and the second main gates 160 being different, the first main gates 170 and the second main gates 160 each extending in the first direction Y, the polarities of the first thin gates and the first main gates 170 being the same, and the polarities of the second thin gates and the second main gates 160 being the same.

Specifically, with continued reference to fig. 3, 5, 8, and 10, the first fine grid extending along the second direction X includes a plurality of first sub-fine grids 140 spaced apart along the second direction X, a portion of the first sub-fine grids 140 are located on the corresponding first portion 112 along the third direction Z, the first portion 112 may be in one-to-one correspondence with the first sub-fine grids 140, the second fine grid extending along the second direction X includes a plurality of second sub-fine grids 150 spaced apart along the second direction X, a portion of the second sub-fine grids 150 are located on the corresponding third portion 122 along the third direction Z, and the third portion 122 may be in one-to-one correspondence with the second sub-fine grids 150.

In the third direction Z, at least a portion of the second main gate 160 is located above a row of the second portions 111 arranged in the first direction Y, the first main gate 170 is crossed and connected with the first sub-fine gate 140, the second main gate 160 is crossed and connected with the second sub-fine gate 150, a space is provided between the first sub-fine gate 140 and the second main gate 160 in the second direction X, a space is provided between the second sub-fine gate 150 and the first main gate 170, the first sub-fine gate 140 is insulated from the second main gate 160, and the second sub-fine gate 150 is insulated from the first main gate 170.

The first main gate 170 is connected with a row of first sub-fine gates 140 arranged along the first direction Y, the second main gate 160 is connected with a row of second sub-fine gates 150 arranged along the first direction Y, and the first main gate 170 not only collects carriers on the first sub-fine gates 140, but also enables carriers to flow between the first doped parts 110 arranged along the first direction Y through the first main gate 170, which is beneficial to improving uniformity of battery performance, relieving mismatch phenomenon, relieving bright and dark phenomenon in subsequent EL test, and further promoting performance of solar batteries.

In some embodiments, the first and second sub-fine gratings 140 and 150 may be sintered from a burn-through paste. In some embodiments, the material of the first sub-fine gate 140 may include one or more of aluminum, silver, gold, nickel, molybdenum, or copper. In some embodiments, the material of the second sub-fine gate 150 may include one or more of aluminum, silver, gold, nickel, molybdenum, or copper.

In some embodiments, the first main gate 170 and the second main gate 160 are formed by non-burning-through paste, and the first main gate 170 and the second main gate 160 are located on the surface of the insulating layer 141 away from the substrate 100, so that the first doped portion 110 and the second doped portion 120 may not need to be typeset to prevent the first main gate 170 from electrically contacting the second doped portion 120 and prevent the second main gate 160 from electrically contacting the first doped portion 110, which may cause a short circuit problem. In addition, the first and second main grids 170 and 160 may not damage the passivation layer, so that the integrity of the film layer of the passivation layer is ensured, thereby improving the passivation effect of the passivation layer on the substrate 100, and being beneficial to reducing the optical loss of the solar cell, thereby improving the photoelectric conversion efficiency of the solar cell. In addition, as the non-burning-through paste does not damage PN junctions due to excessive glass powder, metal recombination can be effectively reduced, the open-circuit voltage of the solar cell is improved, and the conversion efficiency of the solar cell is improved.

The traditional slurry comprises a mixture of metal powder, glass powder and an organic carrier. The non-burn-through type slurry is a slurry which contains glass powder with lower content than the traditional slurry, has weak burn-through capability in the sintering process and does not need or cannot burn through the passivation layer. The burn-through type slurry refers to slurry which has strong burn-through capability and can burn through a passivation layer in the sintering process.

In some embodiments, the conductivity type of the second main gate 160 is different from the conductivity type of the second portion 111. That is, if the second main gate 160 is the positive electrode main gate, the second portion 111 is an N-type doped region; if the second main gate 160 is a negative electrode main gate, the second portion 111 is a P-type doped region.

The second doping part 120 includes a plurality of third portions 122 spaced apart along the second direction X, and for doping types of a spaced region between adjacent third portions 122 spaced apart along the second direction X, specifically, the following two cases may be included:

First, in some embodiments, referring to fig. 3, 4 and 7, the first surface 101 further has a third doped portion 130, the third doped portion 130 is located between two third portions 122 adjacent along the second direction X, the third doped portion 130 is of the same conductivity type as the first doped portion 110, the doping concentration of the third doped portion 130 is the same as the doping concentration of the first portion 112, and at least part of the first main gate 170 is located above a row of the third doped portions 130 arranged along the first direction Y along the thickness direction of the third doped portion 130. That is, if the first doped portion 110 is a P-type doped region, the third doped portion 130 is also a P-type doped region; if the first doped portion 110 is an N-type doped region, the third doped portion 130 is also an N-type doped region.

Specifically, the second doped portion 120 extends along the second direction X, and the second doped portion 120 includes a plurality of third portions 122 arranged at intervals along the second direction X, and the second sub-fine gate 150 is located on the corresponding third portion 122. In the third direction Z, at least part of the first main gate 170 is located above a column of the third doped parts 130 arranged in the first direction Y, and the conductivity type of the first main gate 170 is the same as that of the third doped parts 130. That is, if the first main gate 170 is a positive electrode main gate, the third doped portion 130 is a P-type doped region, and if the first main gate 170 is a negative electrode main gate, the third doped portion 130 is an N-type doped region.

Second, in some embodiments, referring to fig. 8 to 11, the second doping part 120 further includes a fourth portion 121, the fourth portion 121 is located between two third portions 122 adjacent in the second direction X, the doping concentration of the fourth portion 121 is greater than that of the third portion 122, two second sub-fine gates 150 adjacent in the second direction X are connected through the respective fourth portions 121, and at least part of the first main gate 170 is located above a row of the fourth portions 121 arranged in the first direction Y in the thickness direction of the insulating layer 141. That is, if the third portion 122 is a P-type doped region, the fourth portion 121 is also a P-type doped region; if the third portion 122 is an N-doped region, the fourth portion 121 is also an N-doped region.

Specifically, referring to fig. 8 to 11, the second doping portion 120 extends along the second direction X, and the second doping portion 120 includes third portions 122 and fourth portions 121 that are alternately arranged along the second direction X, the doping concentration of the fourth portions 121 is greater than that of the third portions 122, in the second direction X, two adjacent third portions 122 are connected through one fourth portion 121, the second doping portion 120 is a first whole doping area extending along the second direction X, at least part of the second fine carrier grid 150 is located on the corresponding third portion 122, two mutually independent second fine carrier grids 150 along the second direction X are connected through the fourth portion 121, so when the battery performance of the battery area corresponding to different third portions 122 is uneven or an abnormality occurs in a certain battery area, any one third portion 122 can be connected with at least one adjacent third portion 122 through the fourth portion 121, the second fine carrier grid 150 corresponding to one third portion 122 can be connected with at least one other adjacent third portion 122 through the fourth portion 121, the second fine carrier grid 150 corresponding to the second portion adjacent third portion can be better than the second portion 122, the mutual mismatch between the second fine carrier grid 150 and the adjacent third portion can be improved, the mutual mismatch between the second fine carrier grid 150 and the second fine carrier grid 150 can be better, and the mutual mismatch between the second fine carrier grids can be better achieved, and the mutual current can be better relieved, and the mutual mismatch can be better achieved, when the second fine carrier grids and the second fine carrier grids are better.

It should be noted that the substrate 100 has two edges opposite to each other along the second direction X, and the second doped portion 120 located at the outermost side near the edges is the third portion 122.

The third portion 122 is the same conductive type as the fourth portion 121. If the third portion 122 is an N-type doped region, the fourth portion 121 is an N-type doped region, and the doping concentration of the fourth portion 121 is greater than the doping concentration of the third portion 122. If the third portion 122 is a P-type doped region, the fourth portion 121 is a P-type doped region, and the doping concentration of the fourth portion 121 is greater than the doping concentration of the third portion 122. The greater benefit of setting the concentration of the fourth portion 121 is that: the carrier transmission is performed between two adjacent second sub-fine grids 150 along the second direction X through the fourth portion 121, and the fourth portion 121 with larger doping concentration has better carrier transmission capability, so that the resistance is reduced, the recombination loss in the carrier transmission process is reduced, and further the photoelectric conversion efficiency of the solar cell is improved.

In the third direction Z, at least a portion of the first main gate 170 is located over a column of fourth portions 121 arranged in the first direction Y, and in some embodiments, the conductivity type of the first main gate 170 is different from the conductivity type of the fourth portions 121. That is, if the first main gate 170 is a positive electrode main gate, the fourth portion 121 is an N-type doped region; if the first main gate 170 is a negative electrode main gate, the fourth portion 121 is a P-type doped region.

The second main gate 160 not only collects carriers on the second sub-fine gate 150, but also enables carriers to flow between the second doped parts 120 distributed along the first direction Y through the second main gate 160, which is favorable for improving uniformity of battery performance, relieving mismatch phenomenon, and relieving bright and dark phenomenon in subsequent EL test, and further is favorable for improving performance of the solar battery.

In some embodiments, referring to fig. 5 and 10, in the second direction X, the spacing between the second main gate 160 and the first sub-fine gate 140 is 50um to 100um, for example, may be 55um, 56um, 60um, 70um, or 86um. Since the polarities of the second main grid 160 and the first sub-fine grid 140 are different, the distance between the second main grid 160 and the first sub-fine grid 140 in the second direction X is too short, which may cause a short circuit between the second main grid 160 and the first sub-fine grid 140, affecting the performance of the solar cell. If the spacing between the second main gate 160 and the first sub-fine gate 140 is too large, the spacing between two adjacent first sub-fine gates 140 along the second direction X is larger, and the transmission distance of the carriers is further increased, so that the recombination loss is increased, and therefore, the spacing between the second main gate 160 and the first sub-fine gate 140 is set to 50 um-100 um, which is not only beneficial to ensuring the mutual insulation of the gate lines with different polarities, but also beneficial to avoiding the generation of larger recombination loss.

In some embodiments, the distance between the second main gate 160 and the first sub-fine gate 140 along the second direction X may be 50um to 60um; and/or, along the second direction X, the distance between the second main gate 160 and the first sub-fine gate 140 may be 60um to 70um; and/or, along the second direction X, the distance between the second main gate 160 and the first sub-fine gate 140 may be 70um to 80um; and/or, along the second direction X, the distance between the second main gate 160 and the first sub-fine gate 140 may be 80um to 90um; and/or, along the second direction X, the distance between the second main gate 160 and the first sub-fine gate 140 may be 90um to 100um.

In some embodiments, referring to fig. 5 and 10, in the second direction X, the spacing between the first main gate 170 and the second sub-fine gate 150 is 50um to 100um, for example, may be 55um, 56um, 60um, 70um, or 86um. Since the polarities of the first main grid 170 and the second sub-fine grid 150 are different, the distance between the first main grid 170 and the second sub-fine grid 150 along the second direction X is too short, which may cause the first main grid 170 to be connected with the second sub-fine grid 150, thereby affecting the performance of the solar cell. If the spacing between the first main gate 170 and the second sub-fine gate 150 is too large, the spacing between two adjacent second sub-fine gates 150 along the second direction X is larger, and the transmission distance of carriers is further increased, so that the recombination loss is increased, and therefore, the spacing between the first main gate 170 and the second sub-fine gate 150 is set to 50 um-100 um, which is not only beneficial to ensuring the mutual insulation of the gate lines with different polarities, but also beneficial to avoiding the generation of larger recombination loss.

In some embodiments, the distance between the first main gate 170 and the second sub-fine gate 150 along the second direction X may be 50um to 60um; and/or, along the second direction X, the space between the first main gate 170 and the second sub-fine gate 150 may be 60um to 70um; and/or, along the second direction X, the distance between the first main gate 170 and the second sub-fine gate 150 may be 70um to 80um; and/or, along the second direction X, the space between the first main gate 170 and the second sub-fine gate 150 may be 80um to 90um; and/or, along the second direction X, the distance between the first main gate 170 and the second sub-fine gate 150 may be 90um to 100um.

In some embodiments, referring to fig. 3, in the second direction X, the second portion 111 has a smaller size than the first portion 112. The second portion 111 is smaller in size, which is advantageous in avoiding the second portion 111 having a larger doping concentration from having a larger impact on the performance of the first doped portion 110. And is advantageous in avoiding the excessive carrier transport distance caused by the oversized second portion 111, and thus in avoiding the occurrence of large recombination losses.

In some embodiments, referring to fig. 3, in the second direction X, the size of the second portion 111 is greater than the size of the second main gate 160. In this way, along the second direction X, it is not only beneficial to ensure that the second main gate 160 has a sufficient distance from the first sub-fine gate 140 located on the first portion 112 on two opposite sides of the second portion 111, so as to avoid a short circuit phenomenon, but also beneficial to ensure that the distance between the first sub-fine gate 140 and the second portion 111 is relatively short, so that the capability of the two adjacent first sub-fine gates 140 to transmit carriers through the second portion 111 is improved.

In some embodiments, the ratio of the doping concentration of the second portion 111 to the doping concentration of the first portion 112 is 2-10. For example, it may be 3, 4, 5, 7 or 9.

In some embodiments, the ratio of the doping concentration of the second portion 111 to the doping concentration of the first portion 112 is 5-10. For example, it may be 5, 6, 7, 8 or 8.5. If the doping concentration of the second portion 111 is too small, the carrier transmission efficiency between two adjacent first sub-fine gates 140 along the second direction X cannot be effectively improved, and if the doping concentration of the second portion 111 is too large, the doping ions in the second portion 111 are easier to diffuse into the first portion 112, and cause a larger influence on the performance of the first portion 112, so that setting the ratio of the doping concentrations of the second portion 111 and the first portion 112 to 5-10 is beneficial to effectively improving the carrier transmission efficiency and avoiding the larger influence of the second portion 111 on the performance of the first portion 112.

In some embodiments, the ratio of the doping concentration of the second portion 111 to the doping concentration of the first portion 112 is 5-6. In some embodiments, the ratio of the doping concentration of the second portion 111 to the doping concentration of the first portion 112 is 6-7. In some embodiments, the ratio of the doping concentration of the second portion 111 to the doping concentration of the first portion 112 is 7-8. In some embodiments, the ratio of the doping concentration of the second portion 111 to the doping concentration of the first portion 112 is 8-9. In some embodiments, the ratio of the doping concentration of the second portion 111 to the doping concentration of the first portion 112 is 9-10.

In some embodiments, the first doped portion 110 is a P-type doped region, and the doping concentration of the first portion 112 may be 0.9E ¹⁹/cm³~2.2E¹⁹/cm³, for example ：0.91E¹⁹/cm³、0.93E¹⁹/cm³、0.95E¹⁹/cm³、1E¹⁹cm³ or 2E ¹⁹/cm³.

In some embodiments, the first doped portion 110 is a P-type doped region, and in some examples, the doping concentration of the first portion 112 may be 0.9E ¹⁹/cm³~1.5E¹⁹/cm³; in some examples, the doping concentration of the first portion 112 may be 1.5E ¹⁹/cm³~2E¹⁹/cm³; in some examples, the doping concentration of the first portion 112 may be 2E ¹⁹/cm³~2.5E¹⁹/cm³.

In some embodiments, the first doped portion 110 is an N-type doped region, and the doping concentration of the first portion 112 may be 0.9E ²⁰/cm³~2.2E²⁰/cm³, for example ：0.91E²⁰/cm³、0.93E²⁰/cm³、0.95E²⁰/cm³、1E²⁰/cm³ or 2E ²⁰/cm³.

In some embodiments, the first doped portion 110 is an N-type doped region, and in some examples, the doping concentration of the first portion 112 may be 0.9E ²⁰/cm³~1.5E²⁰/cm³; in some examples, the doping concentration of the first portion 112 may be 1.5E ²⁰/cm³~2E²⁰/cm³; in some examples, the doping concentration of the first portion 112 may be 2E ²⁰/cm³~2.5E²⁰/cm³.

In some embodiments, the first doped portion 110 is a P-type doped region, and the doping concentration of the second portion 111 is 0.9E ²⁰/cm³~1.1E²⁰/cm³, which may be ：0.91E²⁰/cm³、0.93E²⁰/cm³、0.95E²⁰/cm³、1E²⁰/cm³ or 1.4E ²⁰/cm³, for example.

In some embodiments, the first doped portion 110 is a P-type doped region, and the doping concentration of the second portion 111 may be 0.9E ²⁰/cm³~1E²⁰/cm³; in some embodiments, the first doped portion 110 is a P-type doped region, and the doping concentration of the second portion 111 may be 1E ²⁰/cm³~1.1E²⁰/cm³.

In some embodiments, the first doped portion 110 is an N-type doped region, and the doping concentration of the second portion 111 is 0.9E ²¹/cm³~1.1E²¹/cm³, which may be ：0.91E²¹/cm³、0.93E²¹/cm³、0.95E²¹/cm³、1E²¹cm³ or 1.4E ²¹/cm³, for example.

In some embodiments, the first doped portion 110 is an N-type doped region, and the doping concentration of the second portion 111 may be 0.9E ²¹/cm³~1E²¹/cm³; in some embodiments, the first doped portion 110 is an N-type doped region, and the doping concentration of the second portion 111 may be 1E ²¹/cm³~1.1E²¹/cm³.

In some embodiments, referring to fig. 5, in the thickness direction of the first doped portion 110, an orthographic projection of the first sub-fine grating 140 on the first surface 101 overlaps a portion of the first portion 112 and a portion of the second portion 111. That is, along the third direction Z, part of the first sub-fine gate 140 is further located on the second portion 111 for connecting the first sub-fine gate 140 with the adjacent first sub-fine gate 140, so that two adjacent first sub-fine gates 140 along the second direction X are both in direct contact with the second portion 111, which is beneficial to improving the carrier transmission efficiency between two adjacent first sub-fine gates 140 along the second direction X, reducing the resistance, reducing the recombination loss in the carrier transmission process, and improving the efficiency of the solar cell.

In some embodiments, referring to fig. 8, the second doping part 120 includes a fourth portion 121, the fourth portion 121 being located between two third portions 122 adjacent in the second direction X, and a size of the fourth portion 121 being smaller than a size of the third portions 122 in the second direction X. Setting the size of the fourth portion 121 smaller is beneficial to avoiding the fourth portion 121 with larger doping concentration from causing larger influence on the performance of the second doping portion 120, and is beneficial to avoiding the overlarge transmission distance of carriers caused by overlarge size of the fourth portion 121, thereby being beneficial to avoiding generating larger recombination loss.

In some embodiments, referring to fig. 8, the second doping part 120 includes a fourth portion 121, the fourth portion 121 being located between two third portions 122 adjacent in the second direction X, and a size of the fourth portion 121 in the second direction X is larger than a size of the first main gate 170. In this way, along the second direction X, not only is it beneficial to ensure that there is a sufficient space between the two second sub-fine gratings 150 located on two opposite sides of the fourth portion 121 and the first main grating 170, so as to avoid a short circuit phenomenon, but also it is beneficial to make the distances between the second sub-fine gratings 150 and the fourth portion 121 closer, so as to promote the ability of the two adjacent second sub-fine gratings 150 along the second direction X to transmit carriers through the fourth portion 121.

In some embodiments, the ratio of the doping concentration of the fourth portion 121 to the doping concentration of the third portion 122 is 2-10. For example, it may be 3, 4, 5, 7 or 9.

In some embodiments, referring to fig. 8, the second doped portion 120 includes a fourth portion 121, the fourth portion 121 is located between two third portions 122 adjacent to each other along the second direction X, and a ratio of a doping concentration of the fourth portion 121 to a doping concentration of the third portions 122 is 5-10. For example, it may be 5, 6, 7, 8 or 8.5. If the doping concentration of the fourth portion 121 is too small, the carrier transmission efficiency between two adjacent second sub-fine gates 150 along the second direction X cannot be effectively improved, and if the doping concentration of the fourth portion 121 is too large, the doping ions in the fourth portion 121 are easier to diffuse into the third portion 122, and cause a larger influence on the performance of the third portion 122, so setting the ratio of the doping concentrations of the fourth portion 121 and the third portion 122 to 5-10 is beneficial to effectively improving the carrier transmission efficiency and avoiding the fourth portion 121 from causing a larger influence on the performance of the third portion 122.

In some embodiments, the ratio of the doping concentration of the fourth portion 121 to the doping concentration of the third portion 122 is 5-6. In some embodiments, the ratio of the doping concentration of the fourth portion 121 to the doping concentration of the third portion 122 is 6-7. In some embodiments, the ratio of the doping concentration of the fourth portion 121 to the doping concentration of the third portion 122 is 7-8. In some embodiments, the ratio of the doping concentration of the fourth portion 121 to the doping concentration of the third portion 122 is 8-9. In some embodiments, the ratio of the doping concentration of the fourth portion 121 to the doping concentration of the third portion 122 is 9-10.

In some embodiments, the second doped portion 120 is a P-type doped region, and the doping concentration of the third portion 122 may be 0.9E ¹⁹/cm³~2.2E¹⁹/cm³, for example ：0.91E¹⁹/cm³、0.93E¹⁹/cm³、0.95E¹⁹/cm³、1E¹⁹cm³ or 2E ¹⁹/cm³.

In some embodiments, the second doped portion 120 is a P-type doped region, and in some examples, the doping concentration of the third portion 122 may be 0.9E ¹⁹/cm³~1.5E¹⁹/cm³; in some examples, the doping concentration of the third portion 122 may be 1.5E ¹⁹/cm³~2E¹⁹/cm³; in some examples, the doping concentration of the third portion 122 may be 2E ¹⁹/cm³~2.5E¹⁹/cm³.

In some embodiments, the second doped portion 120 is an N-type doped region, and the doping concentration of the third portion 122 may be 0.9E ²⁰/cm³~2.2E²⁰/cm³, for example ：0.91E²⁰/cm³、0.93E²⁰/cm³、0.95E²⁰/cm³、1E²⁰cm³ or 2E ²⁰/cm³.

In some embodiments, the second doped portion 120 is an N-type doped region, and in some examples, the doping concentration of the third portion 122 may be 0.9E ²⁰/cm³~1.5E²⁰/cm³; in some examples, the doping concentration of the third portion 122 may be 1.5E ²⁰/cm³~2E²⁰/cm³; in some examples, the doping concentration of the third portion 122 may be 2E ²⁰/cm³~2.5E²⁰/cm³.

In some embodiments, the second doped portion 120 is a P-type doped region, and the doping concentration of the fourth portion 121 is 0.9E ²⁰/cm³~1.1E²⁰/cm³, which may be ：0.91E²⁰/cm³、0.9³E²⁰/cm³、0.95E²⁰/cm³、1E²⁰/cm³ or 1.4E ²⁰/cm³, for example.

In some embodiments, the second doped portion 120 is a P-type doped region, and the doping concentration of the fourth portion 121 may be 0.9E ²⁰/cm³~1E²⁰/cm³; in some embodiments, the second doped portion 120 is a P-type doped region, and the doping concentration of the fourth portion 121 may be 1E ²⁰/cm³~1.1E²⁰/cm³.

In some embodiments, the second doped portion 120 is an N-type doped region, and the doping concentration of the fourth portion 121 is 0.9E ²¹/cm³~1.1E²¹/cm³, which may be ：0.91E²¹/cm³、0.9³E²¹/cm³、0.95E²¹/cm³、1E²¹cm³ or 1.4E ²¹/cm³, for example.

In some embodiments, the second doped portion 120 is an N-type doped region, and the doping concentration of the fourth portion 121 may be 0.9E ²¹/cm³~1E²¹/cm³; in some embodiments, the second doped portion 120 is an N-type doped region, and the doping concentration of the fourth portion 121 may be 1E ²¹/cm³~1.1E²¹/cm³.

It should be noted that the doping concentrations in the embodiments of the present application may be average doping concentrations measured on the surface of the corresponding film layer.

In some embodiments, the second doped portion 120 includes a fourth portion 121, the fourth portion 121 is located between two third portions 122 adjacent along the second direction X, and in the thickness direction of the second doped portion 120, an orthographic projection of the second sub-fine grating 150 on the first surface 101 overlaps with a part of the third portions 122 and a part of the fourth portion 121. That is, along the third direction Z, a portion of the second sub-fine gate 150 is further located on the fourth portion 121 for implementing connection between the second sub-fine gate 150 and the adjacent second sub-fine gate 150, so that two adjacent second sub-fine gates 150 along the second direction X are both in direct contact with the fourth portion 121, which is beneficial to improving the carrier transmission efficiency between two adjacent second sub-fine gates 150 along the second direction X, reducing the resistance, reducing the recombination loss during the carrier transmission process, and improving the efficiency of the solar cell.

Fig. 12 is a schematic structural diagram of a back gate line of another solar cell according to some embodiments of the present application.

Referring to fig. 12, in some embodiments, the first main grid 170 includes first main grid bodies 171 arranged in a first direction Y and first welded portions 172, the first main grid bodies 171 extending in the first direction Y, and the first welded portions 172 having a size greater than that of the first main grid bodies 171 in a second direction X. The second main grid 160 includes second main grid bodies 161 and second welding parts 162 arranged in a second direction X, the second main grid bodies 161 extending in the second direction X, and the second welding parts 162 having a size larger than that of the second main grid bodies 161 in the second direction X.

Referring to fig. 12, in some embodiments, since the first main grid body 171 is smaller in size than the first welding portion 172 in the second direction X, correspondingly, the fourth portion 121 under the first main grid body 171 is smaller in size in the second direction X than the fourth portion 121 under the first welding portion 172 in the second direction X in the third direction. In this manner, it is advantageous to avoid the second sub-fine grating 150 from being connected to the first welded portion 172.

Referring to fig. 12, in some embodiments, since the second main grid body 161 is smaller in size than the second welding part 162 in the second direction X, correspondingly, the second portion 111 under the second main grid body 161 is smaller in size in the second direction X than the second portion 111 under the second welding part 162 in the second direction X in the third direction. In this manner, it is advantageous to avoid the first sub-fine grating 140 from being connected to the second welding portion 162.

Fig. 13 is a schematic top view of a first surface of another solar cell according to some embodiments of the present application.

Referring to fig. 13, in some embodiments, the first portion 112 includes a first lightly doped portion 210 and a first heavily doped portion 211, the first sub-fine gate is located on the first heavily doped portion 211 along the third direction, the doping concentration of the first heavily doped portion 211 is greater than that of the first lightly doped portion 210, and the first heavily doped portion 211 is used as a selective emitter, so that the contact resistance between the first sub-fine gate and the first heavily doped portion 211 can be reduced, and at the same time, the carrier recombination can be reduced, and the output voltage and current of the solar cell can be enhanced, so that the efficiency of the solar cell can be significantly improved.

In some embodiments, the first doped portion 110 is a P-type doped region, and the doping concentration of the first lightly doped portion 210 may be 0.5E ¹⁹/cm³~1.1E¹⁹/cm³, for example ：0.6E¹⁹/cm³、0.7E¹⁹/cm³、0.75E¹⁹/cm³、1E¹⁹cm³ or 1.1E ¹⁹/cm³. In some embodiments, the first doped portion 110 is a P-type doped region, and the doping concentration of the first heavily doped portion 211 may be 1.5E ¹⁹/cm³~3E¹⁹/cm³, for example ：1.71E¹⁹/cm³、1.83E¹⁹/cm³、1.95E¹⁹/cm³、2E¹⁹cm³ or 2.5E ¹⁹/cm³.

In some embodiments, the first doped portion 110 is an N-type doped region, and the doping concentration of the first lightly doped portion 210 may be 0.5E ²⁰/cm³~1.1E²⁰/cm³, for example ：0.6E²⁰/cm³、0.7E²⁰/cm³、0.75E²⁰/cm³、1E²⁰cm³ or 1.1E ²⁰/cm³. In some embodiments, the first doped portion 110 is an N-type doped region, and the doping concentration of the first heavily doped portion 211 may be 1.5E ²⁰/cm³~3E²⁰/cm³, for example ：1.71E²⁰/cm³、1.83E²⁰/cm³、1.95E²⁰/cm³、2E²⁰cm³ or 2.5E ²⁰/cm³.

Referring to fig. 13, in some embodiments, the third portion 122 includes a second lightly doped portion 212 and a second heavily doped portion 213, and the second sub-fine gate is located on the second heavily doped portion 213 along the third direction, the doping concentration of the second heavily doped portion 213 is greater than that of the second lightly doped portion 212, and the second heavily doped portion 213 is used as a selective emitter, so that contact resistance between the second sub-fine gate and the second heavily doped portion 213 is reduced, and carrier recombination is reduced, so that output voltage and current of the solar cell are enhanced, and efficiency of the solar cell is significantly improved.

In some embodiments, the second doped portion 120 is a P-type doped region, and the doping concentration of the second lightly doped portion 212 may be 0.5E ¹⁹/cm³~1.1E¹⁹/cm³, for example ：0.6E¹⁹/cm³、0.7E¹⁹/cm³、0.75E¹⁹/cm³、1E¹⁹cm³ or 1.1E ¹⁹/cm³. In some embodiments, the second doped portion 120 is a P-type doped region, and the doping concentration of the second heavily doped portion 213 may be 1.5E ¹⁹/cm³~3E¹⁹/cm³, for example ：1.71E¹⁹/cm³、1.83E¹⁹/cm³、1.95E¹⁹/cm³、2E¹⁹cm³ or 2.5E ¹⁹/cm³.

In some embodiments, the second doped portion 120 is an N-type doped region, and the doping concentration of the second lightly doped portion 212 may be 0.5E ²⁰/cm³~1.1E²⁰/cm³, for example ：0.6E²⁰/cm³、0.7E²⁰/cm³、0.75E²⁰/cm³、1E²⁰cm³ or 1.1E ²⁰/cm³. In some embodiments, the second doped portion 120 is an N-type doped region, and the doping concentration of the second heavily doped portion 213 may be 1.5E ²⁰/cm³~3E²⁰/cm³, for example, ：1.71E²⁰/cm³、1.83E²⁰/cm³、1.95E²⁰/cm³、2E²⁰cm³ or 2.5E ²⁰/cm³.

In some embodiments, the solar cell further comprises an anti-reflective layer (not shown) on a side of the passivation layer remote from the back surface and on a side of the front passivation layer 180 remote from the substrate 100, the first fine-grid penetrating the anti-reflective layer, the passivation layer being in electrical contact with the first doped surface, the second fine-grid penetrating the anti-reflective layer, the passivation layer being in electrical contact with the second doped surface. The anti-reflection layer has a high refractive index for reducing reflection loss at the back of the cell. In some embodiments, the material of the anti-reflective layer may be any one or more of silicon nitride or silicon oxynitride.

In the solar cell provided by the embodiment of the application, the first portions 112 located at two sides of the second main grid 160 are connected through the second portions 111 along the second direction X, so that when the battery performance in the two side regions of the second main grid 160 along the second direction X is uneven or the battery in one side region is abnormal locally, the battery regions at two sides of the second main grid 160 have different brightness and darkness in the EL test, which is beneficial to reducing the component mismatch and improving the component power. The different first sub-fine gratings 140 located on the first surface 101 may be connected through the first main grating 170 or the second portion 111 with higher doping concentration, and compared with the state that the first sub-fine gratings 140 are independent of each other, the first sub-fine gratings 140 connected with each other reduce the mismatch phenomenon of different areas on the battery piece caused by uneven battery performance or local abnormality, which is beneficial to further reducing component mismatch and further improving component power.

Another embodiment of the present application provides a photovoltaic module, which can be used for assembling the solar cells in the above embodiments, so as to improve the performance of the photovoltaic module. It should be noted that, in the same or corresponding parts as those of the above embodiments, reference may be made to the corresponding descriptions of the above embodiments, and detailed descriptions thereof will be omitted. The photovoltaic module provided in this embodiment will be described in detail below with reference to the accompanying drawings.

The photovoltaic module includes: a cell string formed by connecting a plurality of solar cells as described in the above embodiments; a connection member for electrically connecting adjacent two solar cells; the packaging adhesive film is used for covering the surface of the battery string; and the cover plate is used for covering the surface, deviating from the battery string, of the packaging adhesive film.

Referring to fig. 14, in some embodiments, a plurality of solar cells 200 are sequentially arranged along a first direction Y, wherein the solar cells 200 may have the same structure as any one of the solar cells 200 in the above embodiments, and a detailed description thereof is omitted herein.

Adjacent solar cells 200 are connected through a connection member 201, the connection member 201 is located at a surface of the solar cell 200, which is far from the cell body, and is in electrical contact with the main grid, one end of the connection member 201 is electrically connected with a first main grid of one solar cell 200, the other end of the connection member 201 is electrically connected with a second main grid of another adjacent solar cell 200, and the connection member 201 may be welded to a welding portion of the main grid so that the connection member 201 is electrically connected with the main grid, and a plurality of solar cells 200 are connected in series through the connection member 201.

The connection part 201 may be composed of a conductive layer and a welding layer wrapping the surface of the conductive layer, wherein the material of the conductive layer includes conductive materials with better conductivity such as copper, nickel, gold, silver, etc., or alloy materials with low resistivity; the material of the welding layer comprises tin-zinc alloy, tin-bismuth alloy or tin-indium alloy and other materials with lower melting points.

In some embodiments, a flux may be present within the weld layer, which refers to a chemical substance that aids and facilitates the welding process while protecting against oxidation reactions during the welding process. Because the melting point of the soldering flux is lower than that of the soldering layer, the soldering flux can be beneficial to increasing the fluidity of the soldering layer in a molten state, so that the connecting component and the grid line structure can be better alloyed. In some embodiments, the flux includes an inorganic flux, an organic flux, and a resin flux.

In some embodiments, the encapsulating film may be an organic encapsulating film such as an Ethylene Vinyl Acetate (EVA) film, a polyethylene octene co-elastomer (POE) film, or a polyvinyl butyral (PVB) film. On one hand, the packaging adhesive film can prevent the solar cell from being damaged due to severe environments (such as rain, snow, sand dust, heat and the like), so that the durability of the solar cell is improved, and the service life of the solar cell is prolonged; on the other hand, the packaging adhesive film can also prevent an oxide layer from forming on the surface of the solar cell so as to ensure the highest-efficiency electric energy conversion.

In some embodiments, the cover plate may be a glass cover plate, a plastic cover plate, or the like having a light transmitting function. The cover plate can prevent the solar cell from being influenced by the environment, and the service life and stability of the photovoltaic module are improved.

The photovoltaic module provided by the embodiment of the application comprises the solar cell provided by the implementation, and in the solar cell, the first parts positioned at two sides of the second main grid are connected through the second parts positioned under the second main grid and having higher doping concentration along the second direction, and the mutually independent first sub-fine grids positioned on the first surface can be connected through the first main grid or the second parts having higher doping concentration, so that the phenomenon that the module has different brightness in different areas in an EL test is reduced, and the power of the module is improved.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of carrying out the application and that various changes in form and details may be made therein without departing from the spirit and scope of the application. Variations and modifications may be made by one skilled in the art without departing from the spirit and scope of the application, which is therefore intended to be limited only by the scope of the appended claims.

Claims

1. A solar cell, comprising:

a substrate having a first surface;

The first surface is provided with first doped parts and second doped parts which are alternately arranged along a first direction, the first doped parts are different from the second doped parts in conductivity type, the first doped parts comprise first parts and second parts which are alternately arranged along a second direction, the doping concentration of the second parts is larger than that of the first parts, the second doped parts comprise a plurality of third parts which are alternately arranged along the second direction, and the first direction is intersected with the second direction;

An insulating layer, the insulating layer being located on the first surface;

The thin grids penetrate through the insulating layer along the thickness direction of the insulating layer, the thin grids comprise first thin grids and second thin grids which are alternately arranged along the first direction, the first thin grids comprise a plurality of first sub-thin grids which are alternately arranged along the second direction, the second thin grids comprise a plurality of second sub-thin grids which are alternately arranged along the second direction, at least part of the first sub-thin grids are positioned on the corresponding first parts, two adjacent first sub-thin grids along the second direction are connected through the corresponding second parts, and at least part of the second sub-thin grids are positioned on the corresponding third parts;

First main grids and second main grids which extend along the first direction and are alternately arranged along the second direction, the first main grids and the second main grids are positioned on the insulating layer along the thickness direction of the insulating layer, at least part of the second main grids are positioned above a row of second parts which are arranged along the first direction, the first main grids are connected with the first sub-fine grids, and the second main grids are connected with the second sub-fine grids.

2. The solar cell according to claim 1, wherein the second doping portion further comprises a fourth portion located between two adjacent third portions in the second direction, the doping concentration of the fourth portion being greater than the doping concentration of the third portion, the two adjacent second sub-thin grids in the second direction being connected by the respective fourth portion, and at least part of the first main grid being located above a row of the fourth portions arranged in the first direction in the thickness direction of the insulating layer.

3. The solar cell according to claim 2, wherein the fourth portion has a smaller dimension than the third portion and/or the fourth portion has a larger dimension than the first main grid in the second direction.

4. The solar cell according to claim 2, wherein a ratio of a doping concentration of the fourth portion to a doping concentration of the third portion is 5 to 10.

5. The solar cell according to claim 2, wherein an orthographic projection of the second sub-fine grating on the first surface overlaps with a part of the third portion and a part of the fourth portion in a thickness direction of the second doping portion.

6. The solar cell of claim 2, wherein the first main gate has a conductivity type different from a conductivity type of the fourth portion.

7. The solar cell according to claim 1, wherein the first surface further has a third doped portion located between two of the third portions adjacent in the second direction, the third doped portion being of the same conductivity type as the first doped portion, and the doping concentration of the third doped portion being the same as the doping concentration of the first portion, at least part of the first main gate being located above a row of the third doped portions arranged in the first direction in a thickness direction of the third doped portion.

8. The solar cell according to claim 1, 2 or 7, wherein a pitch between the second main grid and the first sub-fine grid is 50um to 100um and/or a pitch between the first main grid and the second sub-fine grid is 50um to 100um in the second direction.

9. The solar cell of claim 1, wherein the second main gate has a conductivity type different from a conductivity type of the second portion.

10. The solar cell according to claim 1, wherein in the second direction the second portion has a smaller size than the first portion and/or the second portion has a larger size than the second main grid.

11. The solar cell according to claim 1, wherein a ratio of a doping concentration of the second portion to a doping concentration of the first portion is 5-10.

12. The solar cell according to claim 1, wherein an orthographic projection of the first sub-fine grid on the first surface overlaps with a part of the first portion and a part of the second portion in a thickness direction of the first doped portion.

13. A photovoltaic module, comprising:

A cell string formed by connecting a plurality of solar cells according to any one of claims 1 to 12;

a connection member for electrically connecting adjacent two solar cells;

the packaging adhesive film is used for covering the surface of the battery string;

And the cover plate is used for covering the surface, deviating from the battery string, of the packaging adhesive film.