Solar cell, manufacturing method of solar cell and photovoltaic module

Abstract

The invention provides a solar cell, a manufacturing method of the solar cell and a photovoltaic module. The solar cell includes: a substrate having opposite front and back surfaces, the front surface including a first region and a second region; the doping layer comprises a first doping part and a second doping part, the first doping part is located on the first region, the second doping part is located on the second region, and the doping concentration of the first doping part is larger than that of the second doping part; the amorphous silicon layer is located on the surface, away from the substrate, of the first doping part; the first anti-reflection layer is located on the side, away from the doping layer, of the amorphous silicon layer; a tunneling layer on the back surface; the doped conductive layer is positioned on one side, far away from the substrate, of the tunneling layer; the second anti-reflection layer is positioned on one side, far away from the tunneling layer, of the doped conductive layer; the first electrode is located on the side, away from the amorphous silicon layer, of the first anti-reflection layer, and the orthographic projection of the first electrode on the front face is located in the first area; the second electrode is located on the side, away from the doped conductive layer, of the second anti-reflection layer.

Description

Technical Field

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

[0002] Solar cells have good photoelectric conversion capabilities. In solar cells, a diffusion process is required on the surface of the silicon wafer to prepare a pn junction. In current solar cells, the carrier recombination loss is relatively high, which affects the overall performance of the solar cell. Summary of the invention

[0003] The main purpose of the present application is to provide a solar cell, a method for manufacturing a solar cell and a photovoltaic module, so as to at least solve the problem of high carrier recombination loss of solar cells in the prior art.

[0004] To achieve the above-mentioned purpose, according to one aspect of the present application, a solar cell is provided, comprising: a substrate having a relative front side and a back side, the front side comprising a first region and a second region; a doping layer comprising a first doping portion and a second doping portion, the first doping portion being located on the first region, the second doping portion being located on the second region, and the doping concentration of the first doping portion being greater than the doping concentration of the second doping portion; an amorphous silicon layer being located on a surface of the first doping portion away from the substrate; a first anti-reflection layer being located on a side of the amorphous silicon layer away from the doping layer; a tunneling layer being located on the back side; a doped conductive layer being located on a side of the tunneling layer away from the substrate; a second anti-reflection layer being located on a side of the doped conductive layer away from the tunneling layer; a first electrode being located on a side of the first anti-reflection layer away from the amorphous silicon layer, the orthographic projection of the first electrode on the front side being located in the first region; and a second electrode being located on a side of the second anti-reflection layer away from the doped conductive layer.

[0005] Optionally, the doping type of the amorphous silicon layer is the same as the doping type of the doping layer, and the material of the amorphous silicon layer is different from the material of the doping layer.

[0006] Optionally, the doping concentration of the amorphous silicon layer is less than or equal to the doping concentration of the first doping portion, and greater than the doping concentration of the second doping portion.

[0007] Optionally, the thickness of the amorphous silicon layer, the thickness of the second doping portion, and the thickness of the first doping portion increase sequentially.

[0008] Optionally, the doping concentration of the amorphous silicon layer is 1×10 19 cm -3 ~1×10 22 cm -3 .

[0009] Optionally, the doping concentration of the first doping portion is 1×10 19 cm -3~1×10 22 cm -3 , the doping concentration of the second doping part is 1×10 17 cm -3 ~1×10 20 cm -3 .

[0010] Optionally, the amorphous silicon layer has a thickness of 5-50 nm.

[0011] According to another aspect of the present application, a method for manufacturing a solar cell is provided, the solar cell being any type of solar cell, the method comprising: providing a substrate, and forming a first doping portion located on a first region and a second doping portion located on a second region, to obtain a doping layer including the first doping portion and the second doping portion, the substrate having a relative front side and a back side, the front side comprising the first region and the second region, the doping concentration of the first doping portion being greater than the doping concentration of the second doping portion; forming an amorphous silicon layer located on a surface of the first doping portion away from the substrate, and forming a first anti-reflection layer on a side of the amorphous silicon layer away from the doping layer; forming a tunneling layer, a doped conductive layer and a second anti-reflection layer on the back side, the tunneling layer being located on the back side, the doped conductive layer being located on a side of the tunneling layer away from the substrate, and the second anti-reflection layer being located on a side of the doped conductive layer away from the tunneling layer; forming a first electrode located on a side of the first anti-reflection layer away from the amorphous silicon layer, and forming a second electrode located on a side of the second anti-reflection layer away from the doped conductive layer, the orthographic projection of the first electrode on the front side being located in the first region.

[0012] Optionally, forming a first electrode located on a side of the first anti-reflection layer away from the amorphous silicon layer includes: using screen printing technology to print silver paste onto the surface of the first anti-reflection layer away from the amorphous silicon layer; curing and low-temperature sintering the silver paste to obtain the first electrode, and the sintering temperature is less than 300°C.

[0013] According to another aspect of the present application, a photovoltaic assembly is provided, comprising: any type of solar cell; and a packaging structure located on both sides of the solar cell.

[0014] By applying the technical solution of the present application, a first doped portion is arranged between a first electrode and a first region on the front side of a substrate as a heavily doped emitter, which can reduce the contact resistance and metal recombination of the first region and improve the open circuit voltage of the solar cell; a second doped portion is arranged on the second region on the front side of the substrate as a lightly doped emitter, which can reduce Auger recombination and improve short-wave quantum efficiency, thereby improving the short-circuit current of the solar cell; and an amorphous silicon layer is arranged between the highly doped emitter and the first electrode, which can prevent metal atoms in the first electrode from diffusing into the heavily doped emitter, thereby reducing carrier recombination losses between the first electrode and the heavily doped emitter, and reducing the problems of low performance of the solar cell such as photoelectric conversion efficiency, output power and service life caused by carrier recombination losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 A schematic cross-sectional structure diagram of a solar cell provided in an embodiment of the present application is shown;

[0017] Figure 2 A schematic flow chart of a method for preparing a solar cell provided according to an embodiment of the present application is shown.

[0018] The above drawings include the following reference numerals:

[0019] 10. Substrate; 11. Doped layer; 111. First doped portion; 112. Second doped portion; 12. Amorphous silicon layer; 13. First anti-reflection layer; 14. Tunneling layer; 15. Doped conductive layer; 16. Second anti-reflection layer; 17. First electrode; 18. Second electrode. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0022] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] As introduced in the background art, the carrier recombination loss of solar cells in the prior art is relatively high.

[0024] After analysis, it was found that one of the reasons for the high carrier recombination losses in current solar cells is that the metal electrode is in direct contact with the heavily doped emitter, and the metal atoms in the metal electrode diffuse into the emitter, causing carrier recombination losses.

[0025] In order to solve the above technical problems, the embodiments of the present application provide a solar cell, a method for manufacturing a solar cell, and a photovoltaic module.

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0027] An embodiment of the present application provides a solar cell, Figure 1 The cross-sectional structure diagram of a solar cell provided by an embodiment of the present application is exemplarily shown. Figure 1 As shown, the solar cell comprises:

[0028] A substrate 10 having a front side and a back side opposite to each other, wherein the front side includes a first region and a second region;

[0029] Specifically, the substrate 10 is used to receive incident light and generate photogenerated carriers.

[0030] The doping layer 11 comprises a first doping portion 111 and a second doping portion 112, wherein the first doping portion 111 is located on the first region, the second doping portion 112 is located on the second region, and the doping concentration of the first doping portion 111 is greater than the doping concentration of the second doping portion 112;

[0031] an amorphous silicon layer 12, located on a surface of the first doped portion 111 away from the substrate 10;

[0032] A first anti-reflection layer 13, located on a side of the amorphous silicon layer 12 away from the doping layer 11;

[0033] Specifically, the first anti-reflection layer 13 may be located on the surface of the amorphous silicon layer 12 away from the doping layer 11 and on the surface of the second doping portion 112 away from the substrate 10 ; other film layers may also be provided between the first anti-reflection layer 13 and the amorphous silicon layer 12 .

[0034] A tunneling layer 14, located on the back surface;

[0035] A doped conductive layer 15 is located on a side of the tunneling layer 14 away from the substrate 10;

[0036] Specifically, the doped conductive layer 15 may be located on a surface of the tunneling layer 14 away from the substrate 10 ; other film layers may also be disposed between the doped conductive layer 15 and the tunneling layer 14 .

[0037] A second anti-reflection layer 16, located on a side of the doped conductive layer 15 away from the tunneling layer 14;

[0038] Specifically, the second anti-reflection layer 16 may be located on a surface of the doped conductive layer 15 away from the tunneling layer 14 ; other film layers may also be disposed between the doped conductive layer 15 and the tunneling layer 14 .

[0039] A first electrode 17, located on a side of the first anti-reflection layer 13 away from the amorphous silicon layer 12, wherein an orthographic projection of the first electrode 17 on the front surface is located in the first region;

[0040] Specifically, the first electrode 17 can penetrate the first anti-reflection layer 13 and the amorphous silicon layer 12 to be electrically connected to the first doping portion 111 .

[0041] The second electrode 18 is located on a side of the second anti-reflection layer 16 away from the doped conductive layer 15 .

[0042] Specifically, the second electrode 18 may penetrate the second anti-reflection layer 16 and be electrically connected to the doped conductive layer 15 .

[0043] Through the embodiment, a first doped portion is arranged between the first electrode and the first region on the front side of the substrate as a heavily doped emitter, which can reduce the contact resistance and metal recombination of the first region and improve the open circuit voltage of the solar cell; a second doped portion is arranged on the second region on the front side of the substrate as a lightly doped emitter, which can reduce Auger recombination and improve short-wave quantum efficiency, thereby improving the short-circuit current of the solar cell; and an amorphous silicon layer is arranged between the highly doped emitter and the first electrode, which can prevent metal atoms in the first electrode from diffusing into the heavily doped emitter, thereby reducing the carrier recombination loss between the first electrode and the heavily doped emitter, and reducing the problems of low performance such as the photoelectric conversion efficiency, output power and service life of the solar cell caused by the carrier recombination loss.

[0044] In some embodiments, the solar cell is a single-sided cell, that is, it receives solar light only through the front side of the substrate. In some embodiments, the solar cell is a double-sided cell, that is, both the front side and the back side of the substrate are used to receive solar light. In some embodiments, the substrate may be a silicon substrate, and the material of the silicon substrate may include monocrystalline silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon.

[0045] In some embodiments, the front side of the substrate can be set as a pyramid velvet surface, so that the reflectivity of the front side of the substrate to the incident light is small, thereby the light absorption utilization rate is large. The back side of the substrate can be set as a non-pyramid velvet surface, such as a stacked step morphology, so that the tunneling layer located on the back side has a higher density and uniformity, so that the tunneling layer has a good passivation effect on the back side of the substrate. The back side of the substrate can also be set as a pyramid velvet surface.

[0046] In some embodiments, the solar cell is a TOPCon (Tunnel Oxide Passivated Contact) cell.

[0047] In some embodiments, the substrate is an N-type semiconductor substrate, that is, the substrate is doped with N-type ions, which may be any one of phosphorus, arsenic or antimony. The doped layer may be a P-type doped layer, doped with P-type ions, which may be any one of boron, aluminum or gallium, and the doped layer forms a PN junction with the substrate. The doped layer may be obtained by diffusing and doping the surface layer of the substrate with P-type ions, and the doped part of the substrate is converted into the doped layer. The doped conductive layer is an N-type conductive layer, doped with N-type ions.

[0048] In some embodiments, the tunneling layer can cause an asymmetric shift in the energy band on the back side, so that the barrier to the majority carriers is lower than the barrier to the minority carriers. Therefore, the majority carriers can easily perform quantum tunneling through the tunneling layer, while the minority carriers are difficult to pass through the tunneling layer, so as to achieve selective transmission of carriers. In addition, the tunneling layer can also have the effect of chemical passivation of the substrate. The material of the tunneling layer can be a dielectric material, such as silicon oxide.

[0049] In some embodiments, the doped conductive layer may form a field passivation. The doped conductive layer may have doping ions of the same conductivity type as the substrate. The material of the doped conductive layer may be doped silicon, which may specifically include doped polysilicon, doped microcrystalline silicon, or doped amorphous silicon.

[0050] In some embodiments, the first anti-reflection layer can reduce the reflection of incident light by the substrate. The first anti-reflection layer can be a single-layer film structure or a multi-layer film structure. The material of the first anti-reflection layer can include at least one of magnesium fluoride, silicon oxide, aluminum oxide, silicon oxynitride, silicon nitride and titanium oxide.

[0051] In some embodiments, the second anti-reflection layer can play a passivation effect. The second anti-reflection layer can be a single-layer film structure or a multi-layer film structure. The material of the second anti-reflection layer can be one or more of silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride or silicon oxycarbon nitride.

[0052] In some embodiments, the first region is also called a metal region, the second region is also called a non-metal region, the area of ​​the first region is larger than the positive projection area of ​​the first electrode on the substrate, and the second region is the area on the front side of the substrate except the first region.

[0053] In some embodiments, Figure 1 As shown, there are a plurality of first electrodes 17, and the plurality of first electrodes 17 are arranged at intervals, there are also a plurality of first regions, and there are a plurality of corresponding first doped portions 111 and a plurality of amorphous silicon layers 12, and the first doped portions 111 correspond to the amorphous silicon layers 12 one by one, and the amorphous silicon layers 12 correspond to the first electrodes 17 one by one. In some embodiments, there are a plurality of second electrodes 18, and the plurality of second electrodes 18 are arranged at intervals.

[0054] In some embodiments, the doping type of the amorphous silicon layer is the same as the doping type of the doping layer, and the material of the amorphous silicon layer is different from the material of the doping layer. In this embodiment, the amorphous silicon layer and the doping layer are made of different materials and are in contact with each other, so that a heterojunction is formed between the two. The presence of the heterojunction can further improve the field passivation effect of the amorphous silicon layer and reduce the probability of carrier tunneling, thereby further reducing the carrier recombination loss between the first electrode and the heavily doped emitter, so that the solar cell can achieve a higher photoelectric conversion efficiency.

[0055] In some embodiments, the doping concentration of the amorphous silicon layer is less than or equal to the doping concentration of the first doping part, and greater than the doping concentration of the second doping part. The doping concentration of the amorphous silicon layer is less than or equal to the doping concentration of the first doping part, which can reduce the Auger recombination of this film layer and reduce the probability of carrier recombination; and since the amorphous silicon layer forms contact with the first electrode, in order to ensure the normal transmission of carriers, the concentration of the amorphous silicon layer cannot be too low, and the doping concentration of the amorphous silicon layer is greater than the doping concentration of the second doping part, which is conducive to the collection of carriers; in addition, compared with the emitter structure with uniform doping concentration, the present application adopts selective high doping in the first region corresponding to the first electrode, which can further reduce the contact resistance and metal recombination of the metal region, improve the open circuit voltage, and low doping in the second region not corresponding to the first electrode further reduces Auger recombination, improves short-wave quantum efficiency, and thus improves the short-circuit current.

[0056] In some embodiments, the thickness of the amorphous silicon layer, the thickness of the second doping part, and the thickness of the first doping part increase in sequence. That is, the thickness of the first doping part is relatively large, which is conducive to widening the depletion region and improving the field effect. At the same time, the thicker first doping part makes it difficult for the first electrode formed to penetrate the first doping part and contact the substrate during the actual preparation of the first electrode, so as not to destroy the structure of the formed PN junction, which is conducive to ensuring the integrity of the solar cell, thereby further ensuring that the solar cell has good photoelectric conversion performance; the thickness of the second doping part is relatively small, which can ensure low Auger recombination; as a barrier layer and heterojunction layer, the amorphous silicon layer needs to have a certain thickness, and because the amorphous silicon layer itself has parasitic absorption of sunlight, a thinner thickness can ensure a higher utilization rate of the incident light of the solar cell, so the thickness of the amorphous silicon layer is the smallest.

[0057] Those skilled in the art can flexibly set the specific doping concentration of the amorphous silicon layer according to actual needs. In some embodiments, the doping concentration of the amorphous silicon layer is 1×10 19 cm -3 ~1×10 22 cm -3 For example, the doping concentration of the amorphous silicon layer may be 1×1019 cm -3 , 5×10 19 cm -3 , 1×10 20 cm -3 , or 1×10 22 cm -3 In this range, it can be ensured that the content of the doping element in the amorphous silicon layer is not excessive, thereby further ensuring the passivation effect of the amorphous silicon layer.

[0058] Specifically, the doping concentration of the amorphous silicon layer is 1×10 19 cm -3 ~1×10 22 cm -3 In the case of -2 .

[0059] In some embodiments, the doping concentration of the first doping portion is 1×10 19 cm -3 ~1×10 22 cm -3 For example, the doping concentration of the first doping portion may be 1×10 19 cm -3 , 1×10 20 cm -3 , 5×10 21 cm -3 , or 1×10 22 cm -3 etc.; the doping concentration of the second doping part is 1×10 17 cm -3 ~1×10 20 cm -3 For example, the doping concentration of the second doping portion may be 1×10 17 cm -3 , 2×10 18 cm -3 ,6××10 19 cm -3 , or 1××10 20 cm -3Etc. The doping concentration of the first doping part is within this range. On the one hand, the doping concentration of the formed first doping part is higher, so that the first doping part has a smaller square resistance, which can increase the carrier transmission efficiency; on the other hand, within this range, the top surface doping concentration of the first doping part is not too large, that is, the content of the doping element in the first doping part is not too much, so that the problem of more doping elements becoming strong recombination centers due to too many doping elements in the first doping part, resulting in poor passivation ability of the first doping part, can be avoided. The doping concentration of the second doping part is within this range, so that the second doping part has fewer doping elements, so that a better passivation effect can be maintained, thereby further improving the open circuit voltage and short circuit current of the solar cell.

[0060] Specifically, the doping concentration of the first doping portion is 1×10 19 cm -3 ~1×10 22 cm -3 , the doping concentration of the second doping part is 1×10 17 cm -3 ~1×10 20 cm -3 In the case where the composite current density of the first doped portion is less than 500 fAcm -2 , the composite current density of the second doped portion is less than 100fAcm -2 .

[0061] In some embodiments, the thickness of the amorphous silicon layer is 5 to 50 nm. For example, the thickness of the amorphous silicon layer can be 5 nm, 10 nm, 20 nm, 35 nm, or 50 nm. Within this range, the thickness is neither too thick to make the doping process difficult to implement, nor too thin to achieve the desired passivation effect.

[0062] The present application also provides a method for manufacturing a solar cell, wherein the solar cell is the solar cell described above, Figure 2 FIG. 1 is a flow chart of a method for manufacturing a solar cell according to an embodiment of the present application. Figure 2 As shown, the method comprises the following steps:

[0063] Step S201: providing a substrate, and forming a first doping portion located on the first region and a second doping portion located on the second region, to obtain a doping layer including the first doping portion and the second doping portion, wherein the substrate has a front side and a back side opposite to each other, the front side includes the first region and the second region, and the doping concentration of the first doping portion is greater than the doping concentration of the second doping portion;

[0064] Step S202: forming an amorphous silicon layer on a surface of the first doped portion away from the substrate, and forming a first anti-reflection layer on a side of the amorphous silicon layer away from the doped layer;

[0065] Specifically, the first anti-reflection layer may be formed on a side of the amorphous silicon layer away from the doping layer and on a side of the second doping portion away from the substrate.

[0066] Step S203: forming a tunneling layer, a doped conductive layer and a second anti-reflection layer on the back surface, wherein the tunneling layer is located on the back surface, the doped conductive layer is located on a side of the tunneling layer away from the substrate, and the second anti-reflection layer is located on a side of the doped conductive layer away from the tunneling layer;

[0067] Step S204: forming a first electrode on a side of the first anti-reflection layer away from the amorphous silicon layer, and forming a second electrode on a side of the second anti-reflection layer away from the doped conductive layer, wherein the orthographic projection of the first electrode on the front side is located in the first region.

[0068] Through the embodiment, a substrate is first formed, and a first doped portion with a larger doping concentration is formed on a first area on the front side of the substrate, and a second doped portion with a smaller doping concentration is formed on a second area on the front side of the substrate; then an amorphous silicon layer is formed on a surface of the first doped portion away from the substrate; then a tunneling layer, a doped conductive layer and a second anti-reflection layer are sequentially formed on the back side of the substrate; finally, a first electrode is formed on a side of the first anti-reflection layer away from the amorphous silicon layer, and a second electrode is formed on a side of the second anti-reflection layer away from the doped conductive layer. The method of the present application sets a first doped portion between the first electrode and the first region on the front side of the substrate as a heavily doped emitter, which can reduce the contact resistance and metal recombination of the first region and improve the open-circuit voltage of the solar cell; sets a second doped portion on the second region on the front side of the substrate as a lightly doped emitter, which can reduce Auger recombination and improve short-wave quantum efficiency, thereby improving the short-circuit current of the solar cell; in addition, the method sets an amorphous silicon layer between the highly doped emitter and the first electrode, which can prevent metal atoms in the first electrode from diffusing into the heavily doped emitter, thereby reducing the carrier recombination loss between the first electrode and the heavily doped emitter, and reducing the problems of low performance of the solar cell such as photoelectric conversion efficiency, output power and service life caused by carrier recombination losses.

[0069] In some embodiments, step S202: forming an amorphous silicon layer located on a surface of the first doped portion away from the substrate comprises one of the following:

[0070] Step S2021: using plasma enhanced chemical vapor deposition to deposit an amorphous silicon material on a surface of the first doped portion away from the substrate to form the amorphous silicon layer;

[0071] Step S2022: Use a laser beam to irradiate the surface of the initial doping part away from the substrate so that the surface material of the initial doping part is converted into amorphous silicon material to obtain the amorphous silicon layer, and the remaining initial doping part forms the first doping part, and the initial doping part is located on the first region and the material is silicon.

[0072] In the embodiment, the amorphous silicon layer is deposited by plasma enhanced chemical vapor deposition, so that the thickness uniformity of the amorphous silicon layer is better, the non-uniformity in the film forming process is reduced, high-speed film forming can be achieved at a lower temperature, the production efficiency is improved, the gas phase reactants can be activated, the cleanliness and density of the amorphous silicon layer can be improved, thereby improving the deposition quality, and the residual gas can be eliminated during the deposition process, so that the film forming process is relatively clean, and the influence of the residue on the performance of the amorphous silicon layer is reduced; or the doped silicon layer is treated by laser surface treatment to obtain a doped amorphous silicon layer, and the amorphous silicon layer can be obtained in a short time, which has the advantages of high efficiency and speed, and the laser technology can accurately control the processing area and depth, and can achieve precise control, and laser surface treatment is a non-contact technology that will not cause mechanical damage to the silicon layer. In addition, by laser processing the silicon layer, the surface finish, cleanliness and electrical properties of the silicon layer can be improved, thereby improving the quality and stability of the obtained amorphous silicon layer.

[0073] Further, the specific implementation of step S2022 can be: using a laser beam with a wavelength of 300-550nm, a pulse width of 5ps-100ns, a pulse frequency of 50kHz-1250kHz and a scanning speed of 300-80000mm / s to irradiate the surface of the initial doping portion away from the substrate, and the spot area of ​​the laser beam is 5000-50000μm 2 , the power of the laser beam is 1W to 25W.

[0074] In some embodiments, the specific process of forming a first doped portion located on the first region and a second doped portion located on the second region includes: processing the substrate using a furnace tube diffusion process to form a first doped portion on the first region of the front side and a second doped portion on the second region of the front side.

[0075] In some embodiments, step S204: forming a first electrode located on a side of the first anti-reflection layer away from the amorphous silicon layer comprises: step S2041: using screen printing technology to print silver paste on the surface of the first anti-reflection layer away from the amorphous silicon; curing and low-temperature sintering the silver paste to obtain the first electrode, and the sintering temperature is less than 300° C. In this embodiment, the first electrode is formed by a low-temperature printing process, which avoids the crystallization problem of the amorphous silicon layer in the process of forming the first electrode and ensures the stability of the amorphous silicon layer.

[0076] In some embodiments, forming a second electrode located on a side of the second anti-reflection layer away from the doped conductive layer includes: printing silver paste on a surface of the second anti-reflection layer away from the doped conductive layer using a screen printing technique; curing and low-temperature sintering the silver paste to obtain the second electrode, wherein the sintering temperature is less than 300° C. In this embodiment, the second electrode is formed using a low-temperature printing process, thereby avoiding the crystallization problem of the amorphous silicon layer during the formation of the first electrode and ensuring the stability of the amorphous silicon layer.

[0077] Specifically, the second electrode may be formed first, and then the first electrode may be formed.

[0078] In some embodiments, there are multiple first regions, and forming a first doped portion located on the first region includes: forming the first doped portion on each of the first regions in a one-to-one correspondence. Forming an amorphous silicon layer located on a surface of the first doped portion away from the substrate includes: forming the amorphous silicon layer on a surface of each of the first doped portions away from the substrate in a one-to-one correspondence. Forming a first electrode located on a side of the first anti-reflection layer away from the amorphous silicon layer includes: forming a plurality of first electrodes arranged at intervals on a side of the first anti-reflection layer away from the amorphous silicon layer.

[0079] In some embodiments, a second electrode is formed on a side of the second anti-reflection layer away from the doped conductive layer, and a plurality of second electrodes are formed on a side of the second anti-reflection layer away from the doped conductive layer.

[0080] In some embodiments, forming an amorphous silicon layer located on the surface of the first doping portion away from the substrate includes: forming the amorphous silicon layer on the surface of the first doping portion away from the substrate, so that the doping concentration of the amorphous silicon layer is less than or equal to the doping concentration of the first doping portion, and greater than the doping concentration of the second doping portion.

[0081] In some embodiments, the doping concentration of the amorphous silicon layer is 1×10 19 cm -3 ~1×10 22 cm -3 .

[0082] In some embodiments, the doping concentration of the first doping portion is 1×10 19 cm -3 ~1×10 22 cm -3 , the doping concentration of the second doping part is 1×10 17 cm -3 ~1×10 20 cm -3 .

[0083] In some embodiments, forming an amorphous silicon layer on a surface of the first doping portion away from the substrate includes: forming the amorphous silicon layer with a thickness of 5 to 50 nm on the surface of the first doping portion away from the substrate.

[0084] The present application also provides a photovoltaic assembly, which includes: any one of the solar cells described above; and a packaging structure located on both sides of the solar cell.

[0085] The photovoltaic module includes the solar cell and a packaging structure that protects the solar cell. The solar cell is provided with a first doped portion between the first electrode and the first area on the front side of the substrate as a heavily doped emitter, which can reduce the contact resistance and metal recombination of the first area and improve the open circuit voltage of the solar cell; a second doped portion is provided on the second area on the front side of the substrate as a lightly doped emitter, which can reduce Auger recombination and improve short-wave quantum efficiency, thereby improving the short-circuit current of the solar cell; and an amorphous silicon layer is provided between the highly doped emitter and the first electrode, which can prevent metal atoms in the first electrode from diffusing into the heavily doped emitter, thereby reducing the carrier recombination loss between the first electrode and the heavily doped emitter, and reducing the problems of low performance such as the photoelectric conversion efficiency, output power and service life of the solar cell caused by the carrier recombination loss.

[0086] The solar cell of the present application will be described in detail below in combination with specific embodiments and comparative examples.

[0087] Example 1

[0088] This embodiment provides a solar cell, including:

[0089] a substrate having opposite front and back surfaces, the front surface comprising a first region and a second region;

[0090] The doping layer includes a first doping portion and a second doping portion, wherein the first doping portion is located on the first region, the second doping portion is located on the second region, and the doping concentration of the first doping portion is 1×10 22 cm-3 , the doping concentration of the second doping part is 1×10 20 cm -3 ;

[0091] an amorphous silicon layer, located on a surface of the first doping portion away from the substrate, wherein the doping concentration of the amorphous silicon layer is 1×10 22 cm -3 , the thickness of the amorphous silicon layer is 30 nm;

[0092] A first anti-reflection layer is located on a side of the amorphous silicon layer away from the doping layer;

[0093] a tunneling layer, located on the back surface;

[0094] A doped conductive layer, located on a side of the tunneling layer away from the substrate;

[0095] A second anti-reflection layer is located on a side of the doped conductive layer away from the tunneling layer;

[0096] A first electrode is located on a side of the first anti-reflection layer away from the amorphous silicon layer, and an orthographic projection of the first electrode on the front surface is located in the first region;

[0097] The second electrode is located on a side of the second anti-reflection layer away from the doped conductive layer.

[0098] Example 2

[0099] The present application provides a solar cell, which is different from the first embodiment in that the doping concentration of the amorphous silicon layer is 1×10 20 cm -3 .

[0100] Example 3

[0101] The present application provides a solar cell, which is different from the embodiment 1 in that the doping concentration of the first doping part is 1×10 19 cm -3 , the doping concentration of the second doping part is 1×10 17 cm -3 .

[0102] Example 4

[0103] The present application provides a solar cell. The only difference between the solar cell and the embodiment 3 is that the doping concentration of the amorphous silicon layer is 1×10 19 cm -3 .

[0104] Example 5

[0105] The present application provides a solar cell. The only difference between the solar cell and the embodiment 2 is that the doping concentration of the first doping part is 1×10 21 cm -3 , the doping concentration of the second doping part is 1×10 18 cm -3 .

[0106] Example 6

[0107] The present application provides a solar cell, the only difference between the solar cell and the embodiment 1 is that the thickness of the amorphous silicon layer is 5 nm.

[0108] Example 7

[0109] The present application provides a solar cell, the only difference between the solar cell and the embodiment 1 is that the thickness of the amorphous silicon layer is 50 nm.

[0110] Comparative Example 1

[0111] The present application provides a solar cell. The only difference between the solar cell and the embodiment 3 is that the doping concentration of the amorphous silicon layer is 1×10 17 cm -3 .

[0112] Comparative Example 2

[0113] The present application provides a solar cell, which is different from the first embodiment in that the doping concentration of the amorphous silicon layer is 1×10 25 cm -3 .

[0114] Comparative Example 3

[0115] The present application provides a solar cell, which is different from the embodiment 1 in that the doping concentration of the first doping part is 1×10 25 cm -3 , the doping concentration of the second doping part is 1×10 22 cm -3 .

[0116] Comparative Example 4

[0117] The present application provides a solar cell. The only difference between the solar cell and the embodiment 4 is that the doping concentration of the first doping part is 1×10 17 cm -3 , the doping concentration of the second doping part is 1×10 15 cm -3 .

[0118] Comparative Example 5

[0119] The present application provides a solar cell. The only difference between the solar cell and the embodiment 2 is that the doping concentration of the first doping part is 1×10 24 cm -3 , the doping concentration of the second doping part is 1×10 15 cm -3 .

[0120] Comparative Example 6

[0121] The present application provides a solar cell, the only difference between the solar cell and Example 1 is that the thickness of the amorphous silicon layer is 3 nm.

[0122] Comparative Example 7

[0123] The present application provides a solar cell, the only difference between the solar cell and the embodiment 1 is that the thickness of the amorphous silicon layer is 60 nm.

[0124] The performance of the solar cells in Examples 1 to 7 and Comparative Examples 1 to 7 was tested, and the test results are shown in Table 1:

[0125] Table 1

[0126]

[0127]

[0128] From the experimental data, it can be seen that the photoelectric conversion efficiency in Examples 1 to 7 is higher than that in Comparative Examples 1 to 7, and the fill factor in Examples 1 to 7 is slightly higher than that in Comparative Examples 1 to 7 on average, indicating that the solar cell of the present application can reduce carrier recombination losses and improve photoelectric conversion efficiency. From the experimental data, it can also be seen that the open circuit voltage and short circuit current in Examples 3, 5 to 7 are slightly higher than that in Comparative Examples 3 to 5, indicating that the solar cell of the present application can improve the open circuit voltage and short circuit current of the solar cell.

[0129] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0130] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A solar cell, characterized in that: include: a substrate having opposite front and back surfaces, the front surface comprising a first region and a second region; a doping layer, comprising a first doping portion and a second doping portion, wherein the first doping portion is located on the first region, the second doping portion is located on the second region, and the doping concentration of the first doping portion is greater than the doping concentration of the second doping portion; an amorphous silicon layer, located on a surface of the first doped portion away from the substrate; A first anti-reflection layer is located on a side of the amorphous silicon layer away from the doping layer; a tunneling layer, located on the back surface; A doped conductive layer, located on a side of the tunneling layer away from the substrate; A second anti-reflection layer is located on a side of the doped conductive layer away from the tunneling layer; A first electrode is located on a side of the first anti-reflection layer away from the amorphous silicon layer, and an orthographic projection of the first electrode on the front surface is located in the first region; The second electrode is located on a side of the second anti-reflection layer away from the doped conductive layer.

2. The solar cell according to claim 1, characterized in that The doping type of the amorphous silicon layer is the same as that of the doping layer, and the material of the amorphous silicon layer is different from that of the doping layer.

3. The solar cell according to claim 2, characterized in that: The doping concentration of the amorphous silicon layer is less than or equal to the doping concentration of the first doping part, and is greater than the doping concentration of the second doping part.

4. The solar cell according to claim 1, characterized in that The thickness of the amorphous silicon layer, the thickness of the second doping portion, and the thickness of the first doping portion increase in sequence.

5. The solar cell according to any one of claims 1 to 4, characterized in that The doping concentration of the amorphous silicon layer is 1×10 19 cm -3 ~1×10 22 cm -3 .

6. The solar cell according to any one of claims 1 to 4, characterized in that: The doping concentration of the first doping part is 1×10 19 cm -3 ~1×10 22 cm -3 , the doping concentration of the second doping part is 1×10 17 cm -3 ~1×10 20 cm -3 .

7. The solar cell according to any one of claims 1 to 4, characterized in that The thickness of the amorphous silicon layer is 5-50 nm.

8. A method for manufacturing a solar cell, characterized in that: The solar cell is a solar cell according to any one of claims 1 to 7, and the method comprises: Providing a substrate, and forming a first doping portion located on the first region and a second doping portion located on the second region, to obtain a doping layer including the first doping portion and the second doping portion, wherein the substrate has a front side and a back side opposite to each other, the front side includes the first region and the second region, and the doping concentration of the first doping portion is greater than the doping concentration of the second doping portion; forming an amorphous silicon layer on a surface of the first doped portion away from the substrate, and forming a first anti-reflection layer on a side of the amorphous silicon layer away from the doped layer; forming a tunneling layer, a doped conductive layer and a second anti-reflection layer on the back surface, wherein the tunneling layer is located on the back surface, the doped conductive layer is located on a side of the tunneling layer away from the substrate, and the second anti-reflection layer is located on a side of the doped conductive layer away from the tunneling layer; A first electrode is formed on a side of the first anti-reflection layer away from the amorphous silicon layer, and a second electrode is formed on a side of the second anti-reflection layer away from the doped conductive layer, wherein the orthographic projection of the first electrode on the front side is located in the first region.

9. The method according to claim 8, characterized in that Forming a first electrode located on a side of the first anti-reflection layer away from the amorphous silicon layer comprises: Printing silver paste onto the surface of the first anti-reflection layer away from the amorphous silicon layer using a screen printing technique; The silver paste is solidified and sintered at a low temperature to obtain the first electrode, and the sintering temperature is less than 300°C.

10. A photovoltaic module, characterized in that: include: The solar cell according to any one of claims 1 to 7; The packaging structure is located on both sides of the solar cell.

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