Solar cell and manufacturing method for solar cell

Abstract

A solar cell and a manufacturing method for the solar cell. The solar cell comprises: a substrate, having a front surface and a back surface opposite to each other, the back surface comprising a first region and a second region adjacent to each other in a first direction; a first electrode region, arranged below the first region; a second electrode region, arranged below the second region; and cantilever structures, each cantilever structure comprising a body part and an extension part which are connected in the first direction, wherein the body part is in contact with the back surface of the first electrode region, and the extension part protrudes out of the first electrode region in the first direction. According to the solar cell and the manufacturing method for the solar cell, the short-circuit effect between adjacent electrodes can be remarkably reduced or eliminated.

Description

Solar cell and method for manufacturing solar cell Technical Field

[0001] The present application mainly relates to the field of photovoltaic technology, and in particular to a solar cell and a method for manufacturing a solar cell. Background Art

[0002] The types of solar cells mainly include Passivated Emitter and Rear Contact (PERC), Tunnel Oxide Passivated Contact (TOPCON), Hetero-Junction with Intrinsic Thin Film (HIT), and Interdigitated Back Contact (IBC). Among them, PERC cells are the mainstream type of solar cells in the current market, and their mass production efficiency is close to the theoretical limit. Although the photoelectric conversion efficiency of solar cells has gradually increased with the development of solar cell technology, the market's pursuit of higher photoelectric conversion efficiency will never stop.

[0003] Summary of the Invention

[0004] The technical problem to be solved by the present application is to provide a solar cell and a method for manufacturing the solar cell, which can significantly reduce or eliminate the short-circuit effect between adjacent electrodes.

[0005] The present application proposes a solar cell, comprising: a substrate having a front side and a back side relative to each other, the back side having a first region and a second region adjacent to each other in a first direction; a first electrode region arranged below the first region; a second electrode region arranged below the second region; and a cantilever structure, the cantilever structure comprising a main body portion and an extension portion connected in the first direction, wherein the main body portion contacts the back side of the first electrode region, and the extension portion protrudes beyond the first electrode region in the first direction.

[0006] In one embodiment of the present application, the first electrode region includes a tunneling layer and a first doping layer, and the tunneling layer and the first doping layer are sequentially arranged below the first region.

[0007] In one embodiment of the present application, a first passivation layer and a second doping layer are further located below the first region and the second region, and the first passivation layer and the second doping layer extend from the second region to the back side of the cantilever structure, wherein the second electrode region includes the first passivation layer and the second doping layer formed on the second region.

[0008] In one embodiment of the present application, the first passivation layer and the second doping layer continuously extend to the back side of the cantilever structure.

[0009] In one embodiment of the present application, the thickness of the portion of the first passivation layer located on the side of the first electrode region gradually decreases in a direction approaching the extension portion, and the thickness of the portion of the first passivation layer located above the extension portion gradually increases in a direction away from the main portion; the thickness of the portion of the second doped layer located on the side of the first electrode region gradually decreases in a direction approaching the extension portion, and the thickness of the portion of the second doped layer located above the extension portion gradually increases in a direction away from the main portion.

[0010] In one embodiment of the present application, the first passivation layer and the second doping layer extend discontinuously to the back side of the cantilever structure, wherein the first passivation layer and the second doping layer are disconnected at the junction of the main portion and the extension portion.

[0011] In one embodiment of the present application, the thickness of the portion of the first passivation layer located on the side of the first electrode region gradually decreases in a direction approaching the extension portion, and the thickness of the portion of the first passivation layer located above the extension portion gradually increases in a direction away from the main portion; the thickness of the portion of the second doped layer located on the side of the first electrode region gradually decreases in a direction approaching the extension portion, and the thickness of the portion of the second doped layer located above the extension portion gradually increases in a direction away from the main portion.

[0012] In one embodiment of the present application, a transparent conductive layer is also included, which is located on the back side of the second doping layer, wherein the thickness of the portion of the transparent conductive layer located on the side of the first electrode area gradually decreases in a direction approaching the extension portion, and the thickness of the portion of the transparent conductive layer located above the extension portion gradually increases in a direction away from the main body portion.

[0013] In one embodiment of the present application, a distance between a left end of the extending portion and the transparent conductive layer located at a right end of the extending portion is equal to or greater than 200 nm.

[0014] In one embodiment of the present application, a first gate line and a second gate line are further included, wherein the first gate line is electrically connected to the first electrode region through a contact hole.

[0015] In one embodiment of the present application, the first gate line includes a second contact portion and multiple first contact portions, each of the first contact portions is located in a corresponding contact hole, one end of each first contact portion contacts the first electrode region, and the other end contacts the second contact portion.

[0016] In an embodiment of the present application, a width of each of the first contact portions is smaller than a width of the second contact portion.

[0017] On the other hand, the present application also proposes a method for manufacturing a solar cell, comprising: providing a substrate, the substrate having a relative front and back surface, the back surface having a first region and a second region adjacent to each other in a first direction; forming a first electrode region below the first region; forming a second electrode region below the second region; and forming a cantilever structure, the cantilever structure comprising a main body portion and an extension portion connected in the first direction, wherein the main body portion contacts the back surface of the first electrode region, and the extension portion protrudes beyond the first electrode region in the first direction.

[0018] In one embodiment of the present application, the first electrode region includes a tunneling layer and a first doping layer, and the tunneling layer and the first doping layer are sequentially arranged below the first region.

[0019] In one embodiment of the present application, a first passivation layer and a second doping layer are formed, and the first passivation layer and the second doping layer extend from the second region to the back side of the cantilever structure, wherein the second electrode region includes the first passivation layer and the second doping layer formed on the second region.

[0020] In one embodiment of the present application, the first passivation layer and the second doping layer continuously extend to the back side of the cantilever structure.

[0021] In one embodiment of the present application, the thickness of the portion of the first passivation layer located on the side of the first electrode region gradually decreases in a direction approaching the extension portion, and the thickness of the portion of the first passivation layer located above the extension portion gradually increases in a direction away from the main portion; the thickness of the portion of the second doped layer located on the side of the first electrode region gradually decreases in a direction approaching the extension portion, and the thickness of the portion of the second doped layer located above the extension portion gradually increases in a direction away from the main portion.

[0022] In one embodiment of the present application, the first passivation layer and the second doping layer extend discontinuously to the back side of the cantilever structure, wherein the first passivation layer and the second doping layer are disconnected at the junction of the main portion and the extension portion.

[0023] In one embodiment of the present application, the thickness of the portion of the first passivation layer located on the side of the first electrode region gradually decreases in a direction approaching the extension portion, and the thickness of the portion of the first passivation layer located above the extension portion gradually increases in a direction away from the main portion; the thickness of the portion of the second doped layer located on the side of the first electrode region gradually decreases in a direction approaching the extension portion, and the thickness of the portion of the second doped layer located above the extension portion gradually increases in a direction away from the main portion.

[0024] In one embodiment of the present application, a transparent conductive layer is formed, and the transparent conductive layer is located on the back side of the second doping layer, wherein the thickness of the portion of the transparent conductive layer located on the side of the first electrode region gradually decreases in a direction approaching the extension portion, and the thickness of the portion of the transparent conductive layer located above the extension portion gradually increases in a direction away from the main body portion.

[0025] In one embodiment of the present application, a distance between a left end of the extending portion and the transparent conductive layer located at a right end of the extending portion is equal to or greater than 200 nm.

[0026] In one embodiment of the present application, a first gate line and a second gate line are formed, wherein the first gate line is electrically contacted with the first electrode region through a contact hole.

[0027] In one embodiment of the present application, the first gate line is formed after the transparent conductive layer is formed, or the first gate line is formed before the transparent conductive layer is formed.

[0028] In one embodiment of the present application, the first gate line includes a second contact portion and multiple first contact portions, each of the first contact portions is located in a corresponding contact hole, one end of each first contact portion contacts the first electrode region, and the other end contacts the second contact portion.

[0029] In an embodiment of the present application, a width of each of the first contact portions is smaller than a width of the second contact portion.

[0030] The cantilever structure in the solar cell and the method for manufacturing the solar cell of the present application can significantly reduce or eliminate the short-circuit effect between adjacent electrodes.

[0031] Summary of the Figures

[0032] The features and properties of the present invention are further described by the following examples and accompanying drawings.

[0033] In order to make the above-mentioned objects, features and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings, wherein:

[0034] FIG1 is a partial top view of a solar cell according to an embodiment of the present application;

[0035] FIG2 is a schematic cross-sectional view of the solar cell along line AA in FIG1 ;

[0036] FIG3 is an enlarged schematic diagram of the dotted rectangular frame in FIG2 according to one embodiment;

[0037] FIG4 is an enlarged schematic diagram of the dotted rectangular frame in FIG2 according to another embodiment;

[0038] FIG5 is a schematic cross-sectional view of the solar cell along line BB in FIG1 ;

[0039] FIG6 is a schematic cross-sectional view of a solar cell according to an embodiment;

[0040] FIG7 is a schematic cross-sectional view of a solar cell in another embodiment;

[0041] FIG8 is a schematic cross-sectional view of a solar cell according to an embodiment;

[0042] FIG9 is a schematic flow chart of a method for manufacturing a solar cell according to an embodiment of the present application;

[0043] 10 to 17 are schematic cross-sectional views of a solar cell during the process of manufacturing the solar cell.

[0044] Figure 1 is a block diagram of a CMOS process, wherein the first and second regions 112a and 112b are shown in FIG. 1 , and the second regions 112a and 112b are shown in FIG. 1 . A first diffusion layer 120 is shown in FIG. 1 , and a second diffusion layer 150 is shown in FIG. 1 , and a first doping layer 160 is shown in FIG. 1 .

[0045] Preferred embodiments of the present invention

[0046] In order to make the above-mentioned objectives, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0047] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0048] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0049] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is solely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. Furthermore, while the terms used in this application are selected from commonly known and commonly used terms, some terms mentioned in this specification may have been selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of this description. Furthermore, this application should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0050] Flowcharts are used in this application to illustrate the operations performed by systems according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the various steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0051] Next, the solar cell and the method for manufacturing the solar cell of the present application are described through specific embodiments.

[0052] Figure 1 is a partial top view of a solar cell according to an embodiment, and Figure 2 is a cross-sectional view of the solar cell along line AA in Figure 1 . Referring to Figures 1 and 2 , the solar cell includes a substrate 110 , a first electrode region, a second electrode region, and a cantilever structure 130 .

[0053] Specifically, the substrate 110 has a front surface 111 and a back surface 112 that are opposite to each other in a third direction D3 (i.e., the thickness direction of the substrate 110). The back surface 112 has a first region 112a and a second region 112b that are adjacent to each other in a first direction D1. When the solar cell is in operation, the front surface 111 faces the sun.

[0054] The substrate 110 is doped. The doped substrate 110 may be either N-type or P-type monocrystalline silicon. When the substrate 110 is N-type monocrystalline silicon, the doping element may be phosphorus (P) and / or arsenic (As). When the substrate 110 is P-type monocrystalline silicon, the doping element may be boron (B) and / or gallium (Ga).

[0055] The first electrode region is located below the first region 112 a and may include a first doping layer 160 and a tunneling layer 170 . Both the first doping layer 160 and the tunneling layer 170 are located below the first region 112 a , wherein the first doping layer 160 is located below the tunneling layer 170 .

[0056] Specifically, the tunneling layer 170 is formed in the first region 112a, and the first doping layer 160 is formed on the surface of the tunneling layer 170 away from the substrate 110. The tunneling layer 170 can be selected from silicon oxide (SiO x ), silicon oxynitride (SiO y N x ) and aluminum oxide (Al2O3). The thickness of tunneling layer 170 is equal to or less than 3 nm, for example, 1 nm, 1.5 nm, 2 nm, or 2.5 nm. In some embodiments, tunneling layer 170 contains the same doping element as that in substrate 110 and / or first doping layer 160.

[0057] The first doping layer 160 may include doped polysilicon, which may contain one or more of oxygen (O), carbon (C), and nitrogen (N). The doping type of the first doping layer 160 may be the same as that of the substrate 110, or opposite to that of the substrate 110. In some embodiments, the thickness of the first doping layer 160 is equal to or greater than 20 nm and equal to or less than 600 nm, for example, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, or 550 nm. The first doping layer 160 has a passivation effect on the solar cell.

[0058] In some embodiments, the first electrode region further includes a second diffusion layer 150. The second diffusion layer 150 is formed directly on the first region 112a. The second diffusion layer 150 may include crystalline silicon (e.g., single crystal silicon and / or polycrystalline silicon), and the doping type of the second diffusion layer 150 may be the same as or opposite to that of the substrate 110. This application does not limit the doping concentration of the second diffusion layer 150. The doping concentration of the second diffusion layer 150 may be equal to or less than the doping concentration of the first doping layer 160, or may be greater than the doping concentration of the first doping layer 160, or may be greater than the doping concentration of the substrate 110. The second diffusion layer 150 may be formed during the step of forming the first doping layer 160 by diffusing doping elements from the first doping layer 160 into the substrate 110.

[0059] In the case where the solar cell has the second diffusion layer 150 , the tunneling layer 170 and the first doping layer 160 are sequentially stacked on a surface of the second diffusion layer 150 away from the substrate 110 in the third direction D3 .

[0060] The second electrode region is located below the second region 112b. Specifically, the first passivation layer 210 and the second doping layer 230 are sequentially disposed below the first region 112a and the second region 112b. Both the first passivation layer 210 and the second doping layer 230 extend from the second region 112b to the back of the cantilever structure 130. The first passivation layer 210 located below the second region 112b is formed directly on the second region 112b and extends to the back of the cantilever structure 130. The second doping layer 230 is formed on the surface of the first passivation layer 210 away from the substrate 110. In some embodiments, the solar cell may not include the first passivation layer 210. In this case, the second doping layer 230 located below the second region 112b is formed directly on the second region 112b and extends to the back of the cantilever structure 130. The second electrode region includes the first passivation layer 210 and the second doping layer 230 formed on the second region 112b.

[0061] As described with reference to FIG2 , the cantilever structure 130 includes a main body portion 131 and an extension portion 132 that are in contact with each other in a first direction D1. The main body portion 131 is in contact with the back surface of the first electrode region, and the extension portion 132 protrudes from the first electrode region in the first direction D1. FIG3 is an enlarged schematic diagram of the dotted rectangular frame in FIG2 . As shown in FIG2 and FIG3 , the main body portion 131 is located on the left side of the junction 220, and the extension portion 132 is located on the right side of the junction 220. The main body portion 131 is directly formed on the surface of the first doped layer 160 away from the substrate 110. The left end of the extension portion 132 is in contact with the right end of the main body portion 131 at the junction 220. The right end of the extension portion 132 extends rightward along the first direction D1 and protrudes from the first doped layer 160. The size of the extension portion 132 in the first direction D1 is L1, and the size of L1 can be set according to actual conditions. In the first direction D1 , the extension portion 132 protrudes from the first doping layer 160 , and in the third direction D3 , a space S is formed between the extension portion 132 and the first electrode region. In this way, the extension portion 132 is suspended.

[0062] The material of the cantilever structure 130 may include one or more of silicon oxide, silicon nitride (SiN), and silicon oxynitride. Preferably, the material of the cantilever structure 130 is an insulating material. The cantilever structure 130 may contain the same doping elements as the doping elements in the first doping layer 160. These doping elements in the cantilever structure 130 may be intentionally incorporated through a specific process, or may diffuse from the doping elements in the first doping layer 160 into the cantilever structure 130.

[0063] 2 and 3 , the first passivation layer 210 and the second doped layer 230 extend continuously to the back side of the main body 131. The thickness of the first passivation layer 210 located on the sides of the second diffusion layer 150, the tunneling layer 170, and the first doped layer 160 gradually decreases in a direction approaching the extension 132, while the thickness of the first passivation layer 210 located above the extension 132 gradually increases in a direction away from the main body 131 (i.e., the first direction D1). Similarly, the thickness of the second doped layer 230 located on the sides of the second diffusion layer 150, the tunneling layer 170, and the first doped layer 160 gradually decreases in a direction approaching the extension 132, while the thickness of the second doped layer 230 located above the extension 132 gradually increases in a direction away from the main body 131 (i.e., the first direction D1). The thickness of the first passivation layer 210 and the second doping layer 230 in contact with the side surfaces of the second diffusion layer 150, the tunneling layer 170 and the first doping layer 160 gradually decreases, which makes the portion of the first passivation layer 210 in contact with the first electrode region and the portion of the second doping layer 230 in contact with the first electrode region less conductive, thereby significantly reducing the short-circuit effect between the first passivation layer 210 and the first electrode region, and the short-circuit effect between the second doping layer 230 and the first electrode region. The reasons for the change in thickness of the first passivation layer 210 and the second doping layer 230 are as follows. In the process of forming the first passivation layer 210 and the second doping layer 230, the extension portion 132 has a shielding effect, thereby causing the thickness of the first passivation layer 210 and the second doping layer 230 located in the shielded area to change.

[0064] By increasing L1, the thickness of the first passivation layer 210 and the second doping layer 230 located on the sides of the second diffusion layer 150, the tunneling layer 170 and the first doping layer 160 can be reduced, and the thickness of the first passivation layer 210 and the second doping layer 230 located above the extension 132 can be reduced.

[0065] In one embodiment, the first passivation layer 210 may be intrinsic amorphous silicon, which may contain one or more of oxygen, carbon, and nitrogen. These elements are beneficial for improving the passivation effect of the first passivation layer 210 while reducing optical absorption loss. The thickness of the first passivation layer 210 may be any thickness between 3 nm and 15 nm, for example, 5 nm, 7 nm, 9 nm, 11 nm, or 13 nm.

[0066] The second doped layer 230 may be doped amorphous silicon and / or microcrystalline silicon. The doped amorphous silicon and microcrystalline silicon may contain one or more of oxygen, carbon, and nitrogen. The thickness of the second doped layer 230 may be any value within the range of 3 nm to 60 nm, for example, 10 nm, 20 nm, 30 nm, 40 nm, or 50 nm. The doping type of the second doped layer 230 is opposite to that of the first doped layer 160.

[0067] In one embodiment, the solar cell further includes a transparent conductive layer 240. The transparent conductive layer 240 is located on the back side of the second doped layer 230. The thickness of the portion of the transparent conductive layer 240 located on the sides of the second diffusion layer 150, tunneling layer 170, and first doped layer 160 gradually decreases in the direction approaching the extension 132, while the thickness of the portion of the transparent conductive layer 240 located above the extension 132 gradually increases in the direction away from the main body 131 (i.e., the first direction D1). The thickness of the transparent conductive layer 240 gradually decreases in contact with the sides of the second diffusion layer 150, tunneling layer 170, and first doped layer 160. This results in poor conductivity in the portion of the transparent conductive layer 240 in contact with the first electrode region, significantly reducing the short-circuit effect between the transparent conductive layer 240 and the first electrode region. The reason for the variation in thickness of the transparent conductive layer 240 is as follows: During the formation of the transparent conductive layer 240, the extension 132 provides shielding, causing the thickness of the transparent conductive layer 240 in the shielded area to vary.

[0068] By increasing L1 , the thickness of the transparent conductive layer 240 located on the sides of the second diffusion layer 150 , the tunneling layer 170 , and the first doping layer 160 and the thickness of the transparent conductive layer 240 located above the extension 132 can be reduced.

[0069] The transparent conductive layer 240 can be selected from one or more of zinc oxide (ZnO), indium oxide (InO) and tin oxide (SnO), and the transparent conductive layer 240 can contain one or more of gallium (Ga), tin (Sn), molybdenum (Mo), cerium (Ce), fluorine (F), tungsten (W) and aluminum (Al).

[0070] FIG4 is an enlarged schematic diagram of the dashed rectangular box in FIG2 according to another embodiment. Referring to FIG2 to FIG4 , similar to the first passivation layer 210 and the second doping layer 230 in FIG3 , in FIG4 , the thickness of the first passivation layer 210 located on the sides of the second diffusion layer 150, the tunneling layer 170, and the first doping layer 160 gradually decreases in a direction approaching the extension portion 132, while the thickness of the first passivation layer 210 located above the extension portion 132 gradually increases in a direction away from the main body 131 (i.e., the first direction D1). Similarly, the thickness of the second doping layer 230 located on the sides of the second diffusion layer 150, the tunneling layer 170, and the first doping layer 160 gradually decreases in a direction approaching the extension portion 132, while the thickness of the second doping layer 230 located above the extension portion 132 gradually increases in a direction away from the main body 131 (i.e., the first direction D1).

[0071] FIG4 is similar to FIG3 in that the first passivation layer 210 and the second doped layer 230 extend discontinuously to the back surface of the cantilever structure 130. The first passivation layer 210 is disconnected at the interface 220 between the main body portion 131 and the extension portion 132, and the second doped layer 230 is also disconnected at the interface 220 between the main body portion 131 and the extension portion 132. The discontinuous first passivation layer 210 can eliminate the short circuit effect between the first passivation layer 210 and the first electrode region, and the discontinuous second doped layer 230 can eliminate the short circuit effect between the second doped layer 230 and the first electrode region.

[0072] The embodiment of FIG4 may include a transparent conductive layer 240. The transparent conductive layer 240 is located on the back side of the second doping layer 230. The thickness of the portion of the transparent conductive layer 240 located on the side of the second diffusion layer 150, the tunneling layer 170, and the first doping layer 160 gradually decreases in the direction close to the extension portion 132, and the thickness of the portion of the transparent conductive layer 240 located above the extension portion 132 gradually increases in the direction away from the main portion 131 (i.e., the first direction D1). The transparent conductive layer 240 is disconnected at the junction 220 between the main portion 131 and the extension portion 132. The discontinuous transparent conductive layer 240 can eliminate the short circuit effect between the transparent conductive layer 240 and the first electrode region.

[0073] 3 , in one embodiment, a distance L2 between the left end of the extension portion 132 and the transparent conductive layer 240 at the right end of the extension portion 132 is equal to or greater than 200 nm, for example, 400 nm, 600 nm, 800 nm, 1000 nm, or 1200 nm.

[0074] FIG5 is a schematic cross-sectional view of the solar cell along line BB in FIG1 . Referring to FIG1 , FIG2 and FIG5 , in one embodiment, the solar cell has a first gate line 180 and a second gate line 190. The first gate line 180 is electrically connected to the first electrode region, and the second gate line 190 is electrically connected to the second electrode region. Specifically, a plurality of contact holes 140 spaced apart on the second square D2 penetrate the transparent conductive layer 240, the second doped layer 230, the first passivation layer 210 and the cantilever structure 130, the contact holes 140 expose the first doped layer 160, and at least a portion of the first gate line 180 is located within the contact holes 140. It will be understood that the contact holes 140 cannot be observed in FIG1 , and the contact holes 140 in FIG1 are used to illustrate the positions of the contact holes 140.

[0075] The contact hole 140 may not penetrate into the interior of the first doped layer 160, that is, the contact hole 140 exposes the surface of the first doped layer 160 away from the substrate 110. The contact hole 140 may also penetrate into the interior of the first doped layer 160, that is, the contact hole 140 exposes the interior of the first doped layer 160. Protruding the contact hole 140 into the interior of the first doped layer 160 can increase the process window for forming the contact hole 140.

[0076] 2 and 5 , in one embodiment, the first gate line 180 includes a second contact portion 182 and a plurality of first contact portions 181. The first contact portion 181 is located within the corresponding contact hole 140, and the second contact portion 182 is located outside the contact hole 140. One end of each first contact portion 181 contacts the first doped layer 160, and the other end contacts the second contact portion 182. The width of the first contact portion 181 (the dimension of the first contact portion 181 in the first direction D1 in FIG. 2 ) is smaller than the width of the second contact portion 182 (the dimension of the second contact portion 182 in the first direction D1 in FIG. 2 ). For ease of understanding, FIG. 5 does not show the first gate line 180 within the left contact hole 140.

[0077] The contact between first gate line 180 and first doped layer 160 introduces metal-semiconductor recombination losses (J0, metal), thereby reducing the efficiency of the solar cell. The contact between first gate line 180 and first doped layer 160 through contact hole 140 reduces the contact area between first gate line 180 and first doped layer 160, thereby reducing metal-semiconductor recombination losses and improving the efficiency of the solar cell.

[0078] 2 and 5 , in one embodiment, a transparent conductive layer 240 is further formed on the sidewalls and bottom surface of the contact hole 140, and the first gate line 180 located in the contact hole 140 is electrically connected to the first doped layer 160 via the transparent conductive layer 240 in the contact hole 140. In other embodiments, the transparent conductive layer 240 is not formed on the sidewalls and bottom surface of the contact hole 140, and the first gate line 180 located in the contact hole 140 directly contacts the sidewalls and bottom surface of the contact hole 140.

[0079] Referring to Figures 1 and 2, in one embodiment, the solar cell further includes a first isolation trench 250 and a second isolation trench 260. The first isolation trench 250 and the second isolation trench 260 are disposed on both sides of the first gate line 180 along a first direction D1, and both the first isolation trench 250 and the second isolation trench 260 penetrate the transparent conductive layer 240, the second doped layer 230, and the first passivation layer 210 located below the first region 112a. The first isolation trench 250 and the second isolation trench 260 can isolate the transparent conductive layer 240, the second doped layer 230, and the first passivation layer 210, thereby achieving electrical isolation between the first gate line 180 and the adjacent second gate line 190, thereby preventing the transparent conductive layer 240, the second doped layer 230, and the first passivation layer 210 from connecting the first gate line 180 and the second gate line 190, thereby preventing a short circuit between adjacent electrodes of the solar cell. In some other embodiments, the first isolation trench 250 and the second isolation trench 260 may extend into the first doping layer 160 along the third direction D3 and may not penetrate the first doping layer 160 . The first isolation trench 250 and the second isolation trench 260 may also penetrate only the transparent conductive layer 240 .

[0080] As previously mentioned, gradually reducing the thickness of the first passivation layer 210 and the second doping layer 230, which are in contact with the side surfaces of the second diffusion layer 150, the tunneling layer 170, and the first doping layer 160, can significantly reduce the short-circuit effect. In this case, as shown in Figures 6, 7, and 8, short circuits between adjacent electrodes can be avoided even without the first isolation trench 250 and the second isolation trench 260 shown in Figure 2, thus saving the process steps of forming the first isolation trench 250 and the second isolation trench 260.

[0081] Refer to FIG7 for a cross-sectional schematic diagram of a solar cell in another embodiment. The cantilever structure in FIG7 is a broken cantilever structure. Specifically, a portion of the extension portion 132 away from the main body portion 131 in the first direction D1 is broken, and the break is located to the right of the junction 220. The broken cantilever structure physically disconnects the first passivation layer 210, the second doping layer 230, and the transparent conductive layer 240, thereby helping to prevent a short circuit between the two poles. The number of cantilever structures in the solar cell is greater than one, and a portion of the cantilever structures may be broken.

[0082] 8 , a method for breaking the extension portion 132 is provided. During the printing process of the first grid line 180 and the second grid line 190 , when the scraper scrapes across the extension portion 132 , the mesh 270 presses and breaks the extension portion 132 .

[0083] As shown in FIG2 , in one embodiment, the solar cell further includes a first diffusion layer 120. The first diffusion layer 120 is located above the substrate 110. The first diffusion layer 120 may be crystalline silicon, and the doping type of the first diffusion layer 120 may be the same as or opposite to that of the substrate 110. The doping concentration of the first diffusion layer 120 may be equal to or greater than the doping concentration of the substrate 110. The thickness of the first diffusion layer 120 may be any value within a range of 10 nm to 1500 nm.

[0084] In one embodiment, the solar cell further includes a second passivation layer 280 and an anti-reflection layer 290. The second passivation layer 280 and the anti-reflection layer 290 are sequentially disposed on the surface of the first diffusion layer 120 away from the substrate 110 along the third direction D3. The second passivation layer 280 can be selected from intrinsic amorphous silicon, amorphous silicon containing one or more of oxygen, carbon, and nitrogen, silicon oxide, silicon oxynitride, or aluminum oxide. The second passivation layer 280 has a passivating effect and can improve the efficiency of the solar cell. In one embodiment, the thickness of the second passivation layer 280 is equal to or greater than 1.5 nm. The anti-reflection layer 290 can be made of a dielectric material such as silicon oxide or silicon oxynitride. The thickness of the anti-reflection layer 290 is equal to or greater than 40 nm. The anti-reflection layer 290 can increase the solar cell's absorption of incident light, thereby improving the solar cell's utilization of incident light.

[0085] In some embodiments, the solar cell 100 may not have the first diffusion layer 120 , and the second passivation layer 280 may be directly formed on the front surface of the substrate 110 .

[0086] The present application also provides a method for manufacturing a solar cell. Referring to FIG9 , which is a flow chart of a method for manufacturing a solar cell according to an embodiment, the embodiment includes the following steps:

[0087] Step S310: providing a substrate, wherein the substrate has a front surface and a back surface opposite to each other, and the back surface has a first region and a second region adjacent to each other in a first direction;

[0088] Step S320: forming a first electrode region below the first region;

[0089] Step S330: forming a second electrode region below the second region;

[0090] Step S340 : forming a cantilever structure, the cantilever structure comprising a main portion and an extension portion connected in a first direction, the main portion contacting the back surface of the first electrode region, and the extension portion protruding from the first electrode region in the first direction.

[0091] 10 to 17 are schematic cross-sectional views of a solar cell during the manufacturing process of the solar cell. Steps S310 to S340 are described with reference to FIG10 to 17.

[0092] 10 , in step S310 , a substrate 110 is provided. The substrate 110 has a front surface 111 and a back surface 112 opposite to each other. The back surface 112 has a first region 112 a and a second region 112 b adjacent to each other in a first direction D1 .

[0093] 8 to 13 , in step S320, a first electrode region is formed below the first region 112 a. The first electrode region includes a tunneling layer 170 and a first doped layer 160. In some embodiments, the first electrode region further includes a second diffusion layer 150. The second diffusion layer 150 is formed directly in the first region 112 a. The tunneling layer 170 and the first doped layer 160 are sequentially stacked on a surface of the second diffusion layer 150 away from the substrate 110.

[0094] 10 to 12 , a first diffusion layer 120 is formed on the front surface 111 of the substrate 110 , and an initial second diffusion layer 150 - 1 , an initial tunneling layer 170 - 1 , an initial first doping layer 160 - 1 and an initial cantilever structure 130 - 1 are sequentially formed on the back surface 112 .

[0095] As shown in FIG12 and FIG13 , in some embodiments, the first diffusion layer 120 may not be formed, or the first diffusion layer 120 may be removed after the first diffusion layer 120 is formed. In some embodiments, the initial second diffusion layer 150-1 may not be formed. In this case, the tunneling layer 170 is directly formed in the first region 112a, and the first doping layer 160 is formed on a surface of the tunneling layer 170 away from the substrate 110.

[0096] Next, referring to Figures 12 and 13, the initial second diffusion layer 150-1, the initial tunneling layer 170-1, the initial first doping layer 160-1 and the initial cantilever structure 130-1 in the second region 112b are removed, and the initial second diffusion layer 150-1, the initial tunneling layer 170-1, the initial first doping layer 160-1 and the initial cantilever structure 130-1 in the first region 112a are retained. The retained initial second diffusion layer 150-1, the initial tunneling layer 170-1, the initial first doping layer 160-1 and the initial cantilever structure 130-1 become the second diffusion layer 150, the tunneling layer 170, the first doping layer 160 and the cantilever structure 130, respectively.

[0097] Referring to Figures 13 and 14, in step S330, a second electrode region is formed below the second region 112b. Specifically, a first passivation layer 210 and a second doping layer 230 are sequentially formed below the second region 112b. The first passivation layer 210 and the second doping layer 230 extend to the back side of the cantilever structure 130. The first passivation layer 210 below the second region 112b is directly formed on the second region 112b, and the second doping layer 230 below the second region 112b is directly formed on the surface of the first passivation layer 210 away from the substrate 110. The second electrode region includes the first passivation layer 210 and the second doping layer 230 formed on the second region 112b. In other embodiments, the solar cell may not have the first passivation layer 210, and the second doping layer 230 may be directly formed in the second region 112b and extend to the back side of the cantilever structure 130.

[0098] 2 and 3 , in one embodiment, the first passivation layer 210 and the second doped layer 230 extend continuously to the back side of the cantilever structure 130. The thickness of the first passivation layer 210 located on the side of the first electrode region gradually decreases in a direction approaching the extension portion 132, while the thickness of the first passivation layer 210 located above the extension portion 132 gradually increases in a direction away from the body portion 131. The thickness of the second doped layer 230 located on the side of the first electrode region gradually decreases in a direction approaching the extension portion 132, while the thickness of the second doped layer 230 located above the extension portion gradually increases in a direction away from the body portion 131.

[0099] 2 and 4 , in another embodiment, the first passivation layer 210 and the second doping layer 230 extend discontinuously to the back side of the cantilever structure 130, and the first passivation layer 210 and the second doping layer 230 are disconnected at the junction 220 between the main portion 131 and the extension portion 132. The thickness of the portion of the first passivation layer 210 located on the side of the first electrode region gradually decreases in the direction approaching the extension portion 132, and the thickness of the portion of the first passivation layer 210 located above the extension portion 132 gradually increases in the direction away from the main portion 131. The thickness of the portion of the second doping layer 230 located on the side of the first electrode region gradually decreases in the direction approaching the extension portion 132, and the thickness of the portion of the second doping layer 230 located above the extension portion 132 gradually increases in the direction away from the main portion 131. For other explanations on the thickness changes of the first passivation layer 210 and the second doping layer 230, please refer to the relevant explanations above, which will not be elaborated here.

[0100] 2 , 12 , and 13 , in step S340, a cantilever structure 130 is formed below the first region 112 a. The cantilever structure 130 includes a main portion 131 and an extension portion 132 connected in a first direction D1. The main portion 131 contacts the back surface of the first electrode region, and the extension portion 132 protrudes beyond the first electrode region in the first direction D1.

[0101] The method for forming the cantilever structure 130 includes: during the process of forming the pyramid texture morphology in the second region 112b, the chemical reagent has different etching rates for different materials, so that the chemical reagent etches the initial second diffusion layer 150-1, the initial tunneling layer 170-1, and the initial first doping layer 160-1 more than the initial cantilever structure 130-1, thereby forming an extension portion 132 that protrudes from the second diffusion layer 150, the tunneling layer 170, and the first doping layer 160 in the first direction D1. For further details about the cantilever structure, please refer to the previous text and will not be elaborated here.

[0102] With reference to Figures 15 to 17 , a first gate line 180 and a second gate line 190 are formed. Specifically, with reference to Figure 15 , a contact hole 140 is formed that penetrates the first passivation layer 210, the second doping layer 230, and the cantilever structure 130, and the contact hole 140 exposes the first doping layer 160. With reference to Figures 15 and 16 , a transparent conductive layer 240 is formed on the surface of the second doping layer 230 away from the substrate 110, and the transparent conductive layer 240 covers the sidewalls and bottom surface of the contact hole 140. With reference to Figures 16 and 17 , a first gate line 180 is formed in the contact hole 140, and a transparent conductive layer 240 is formed between the first gate line 180 and the bottom surface of the contact hole 140, as well as between the first gate line 180 and the sidewalls of the contact hole 140. In some other embodiments, the contact hole 140 is formed after the first gate line 180 is formed, and the first gate line 180 is formed in the contact hole 140. In this case, the sidewalls and bottom surface of the contact hole 140 are not covered with the transparent conductive layer 240, and the first gate line 180 directly contacts the sidewalls and bottom surface of the contact hole 140.

[0103] 2 and 5 , the first gate line 180 includes a second contact portion 182 and a plurality of first contact portions 181. Each first contact portion 181 is located within a corresponding contact hole 140. One end of each first contact portion 181 is in electrical contact with the first doped layer 160, and the other end is in electrical contact with the second contact portion 182. In one embodiment, the width of each first contact portion 181 (the dimension of the first contact portion 181 in the first direction D1 in FIG. 2 ) is smaller than the width of the second contact portion 182 (the dimension of the second contact portion 182 in the first direction D1 in FIG. 2 ).

[0104] As shown in FIG3 , the thickness of the portion of the transparent conductive layer 240 located on the side of the first electrode region gradually decreases in a direction approaching the extension portion 132, while the thickness of the portion of the transparent conductive layer 240 located above the extension portion 132 gradually increases in a direction away from the main body 131. As shown in FIG3 , the transparent conductive layer 240 can extend continuously from the second region 112b to the first region 112a. As shown in FIG4 , the transparent conductive layer 240 can also extend discontinuously from the second region 112b to the first region 112a, i.e., the transparent conductive layer 240 is disconnected at the junction 220.

[0105] As shown in FIG3 , the distance L2 between the left end of the extension portion 132 and the transparent conductive layer 240 located at the right end of the extension portion 132 is equal to or greater than 200 nm, for example, 400 nm, 600 nm, 800 nm, 1000 nm, or 1200 nm. Referring to FIG17 , in one embodiment, the maximum distance between the pyramid velvet morphology in the second region and the second diffusion layer 150 in the third direction D3 is H1, and H1 is equal to or greater than 0.2 μm, for example, 0.5 μm, 1 μm, or 1.5 μm. In conjunction with FIG2 , in some other embodiments, H1 is equal to or greater than the sum of the thicknesses of the second diffusion layer 150, the tunneling layer 170, and the first doped layer 160. As described in conjunction with FIG3 and FIG17 , L1 can be increased by increasing H1.

[0106] 17 , a first isolation trench 250 and a second isolation trench 260 are formed on both sides of the first gate line 180 and penetrate the transparent conductive layer 240 , the second doping layer 230 and the first passivation layer 210 .

[0107] In one embodiment, a second passivation layer 280 and an anti-reflection layer 290 are sequentially formed on the substrate 110 .

[0108] For other details about the manufacturing method of the present application, please refer to the above description of the solar cell, which will not be elaborated here.

[0109] The basic concepts have been described above. It will be apparent to those skilled in the art that the above disclosures are merely examples and do not limit the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and revisions to the present application. Such modifications, improvements, and revisions are suggested in the present application and remain within the spirit and scope of the exemplary embodiments of the present application.

[0110] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0111] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

Claims

1. A solar cell, characterized in that: include: a substrate having a front surface and a back surface opposite to each other, the back surface having a first region and a second region adjacent to each other in a first direction; a first electrode region, disposed below the first region; a second electrode region, disposed below the second region; a cantilever structure comprising a main portion and an extension portion connected in the first direction, wherein the main portion contacts the back surface of the first electrode region, the extension portion protrudes from the first electrode region in the first direction, and the cantilever structure is made of an insulating material; as well as A first passivation layer and a second doping layer are located below the first region and the second region, the first passivation layer and the second doping layer extend from the second region to the back side of the cantilever structure, the second electrode region includes a first passivation layer and a second doping layer formed on the second region, the thickness of the first passivation layer located on the side of the first electrode region gradually decreases in a direction close to the extension portion, and the thickness of the second doping layer located on the side of the first electrode region gradually decreases in a direction close to the extension portion.

2. The solar cell according to claim 1, wherein The first electrode region includes a tunneling layer and a first doping layer, and the tunneling layer and the first doping layer are sequentially arranged below the first region.

3. The solar cell according to claim 1, wherein The first passivation layer and the second doping layer continuously extend to the back side of the cantilever structure.

4. The solar cell according to claim 3, wherein The thickness of a portion of the first passivation layer located above the extension portion gradually increases in a direction away from the main portion, and the thickness of a portion of the second doping layer located above the extension portion gradually increases in a direction away from the main portion.

5. The solar cell according to claim 1, wherein The first passivation layer and the second doping layer extend discontinuously to the back side of the cantilever structure, wherein the first passivation layer and the second doping layer are disconnected at a junction between the main portion and the extension portion.

6. The solar cell according to claim 5, wherein The thickness of a portion of the first passivation layer located above the extension portion gradually increases in a direction away from the main portion, and the thickness of a portion of the second doping layer located above the extension portion gradually increases in a direction away from the main portion.

7. The solar cell according to claim 4 or 6, characterized in that It also includes a transparent conductive layer, which is located on the back side of the second doping layer, wherein the thickness of the portion of the transparent conductive layer located on the side of the first electrode area gradually decreases in the direction approaching the extension portion, and the thickness of the portion of the transparent conductive layer located above the extension portion gradually increases in the direction away from the main body portion.

8. The solar cell according to claim 7, wherein A distance between a left end of the extending portion and the transparent conductive layer located at a right end of the extending portion is equal to or greater than 200 nm.

9. The solar cell according to claim 1, wherein The invention further comprises a first gate line and a second gate line, wherein the first gate line is in electrical contact with the first electrode region through a contact hole.

10. The solar cell according to claim 9, wherein The first gate line includes a second contact portion and a plurality of first contact portions. Each of the first contact portions is located in a corresponding contact hole. One end of each of the first contact portions contacts the first electrode region, and the other end contacts the second contact portion.

11. The solar cell according to claim 10, wherein The width of each of the first contact portions is smaller than the width of the second contact portion.

12. A method for manufacturing a solar cell, characterized in that: include: Providing a substrate having a front surface and a back surface opposite to each other, the back surface having a first region and a second region adjacent to each other in a first direction; forming a first electrode region below the first region; forming a second electrode region below the second region; forming a cantilever structure, the cantilever structure comprising a main portion and an extension portion connected in the first direction, wherein the main portion contacts the back surface of the first electrode region, the extension portion protrudes from the first electrode region in the first direction, and the cantilever structure is made of an insulating material; and A first passivation layer and a second doping layer are formed, and the first passivation layer and the second doping layer extend from the second region to the back side of the cantilever structure, wherein the second electrode region includes a first passivation layer and a second doping layer formed on the second region, and the thickness of a portion of the first passivation layer located on a side of the first electrode region gradually decreases in a direction approaching the extension portion, and the thickness of a portion of the second doping layer located on a side of the first electrode region gradually decreases in a direction approaching the extension portion.

13. The method for manufacturing a solar cell according to claim 12, wherein: The first electrode region includes a tunneling layer and a first doping layer, and the tunneling layer and the first doping layer are sequentially arranged below the first region.

14. The method for manufacturing a solar cell according to claim 12, wherein: The first passivation layer and the second doping layer continuously extend to the back side of the cantilever structure.

15. The method for manufacturing a solar cell according to claim 14, wherein: The thickness of a portion of the first passivation layer located above the extension portion gradually increases in a direction away from the main portion, and the thickness of a portion of the second doping layer located above the extension portion gradually increases in a direction away from the main portion.

16. The method for manufacturing a solar cell according to claim 12, wherein: The first passivation layer and the second doping layer extend discontinuously to the back side of the cantilever structure, wherein the first passivation layer and the second doping layer are disconnected at a junction between the main portion and the extension portion.

17. The method for manufacturing a solar cell according to claim 16, wherein: The thickness of a portion of the first passivation layer located above the extension portion gradually increases in a direction away from the main portion, and the thickness of a portion of the second doping layer located above the extension portion gradually increases in a direction away from the main portion.

18. The method for manufacturing a solar cell according to claim 15 or 17, wherein: A transparent conductive layer is formed, wherein the transparent conductive layer is located on the back side of the second doping layer, wherein the thickness of the portion of the transparent conductive layer located on the side of the first electrode region gradually decreases in a direction approaching the extension portion, and the thickness of the portion of the transparent conductive layer located above the extension portion gradually increases in a direction away from the main body portion.

19. The method for manufacturing a solar cell according to claim 18, wherein: A distance between a left end of the extending portion and the transparent conductive layer located at a right end of the extending portion is equal to or greater than 200 nm.

20. The method for manufacturing a solar cell according to claim 12, wherein: A first gate line and a second gate line are formed, wherein the first gate line is in electrical contact with the first electrode region through a contact hole.

21. The method for manufacturing a solar cell according to claim 20, wherein: The first gate line is formed after forming the transparent conductive layer, or the first gate line is formed before forming the transparent conductive layer.

22. The method for manufacturing a solar cell according to claim 20, wherein: The first gate line includes a second contact portion and a plurality of first contact portions. Each of the first contact portions is located in a corresponding contact hole. One end of each of the first contact portions contacts the first electrode region, and the other end contacts the second contact portion.

23. The method for manufacturing a solar cell according to claim 22, wherein: The width of each of the first contact portions is smaller than the width of the second contact portion.

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