Solar cell and photovoltaic module

Abstract

The invention provides a solar cell and a photovoltaic module, the solar cell comprises an N-type substrate, an isolation structure located on a first surface, a doping structure, a first passivation layer and a plurality of first electrodes, the doping structure comprises a first P-type doped emitter and a second P-type doped emitter, the second P-type doped emitter is located in a metal contact area, and the first P-type doped emitter and the second P-type doped emitter are arranged on the first surface of the N-type substrate. The isolation structure is located between two adjacent second P-type doped emitters and used for isolating the first electrode and the N-type substrate, the first P-type doped emitter is located in the non-metal contact area, the first passivation layer is located on the side, away from the N-type substrate, of the doped structure in the non-metal contact area, and the first electrode is located on the side, away from the N-type substrate, of the isolation structure; the second tunneling dielectric layer, the second doped conductive layer, the second passivation layer and the plurality of second electrodes are located on the second surface. The solar cell solves the technical problem of how to improve the efficiency of the solar cell in the prior art.

Description

Technical Field

[0001] The present application relates to the field of solar cells, and in particular to 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.

[0003] In current solar cells, a boron diffusion process is usually performed on the surface of the silicon wafer to form an emitter on the surface of the silicon wafer. The emitter forms a PN junction with the silicon wafer on the one hand, and is electrically connected to the metal electrode on the other hand, so that the carriers moving in the emitter can be collected by the metal electrode.

[0004] However, current solar cells have poor efficiency. Summary of the invention

[0005] The main purpose of the present invention is to provide a solar cell and a photovoltaic module to solve the problem of how to improve the efficiency of solar cells in the prior art.

[0006] To achieve the above-mentioned purpose, according to one aspect of the present invention, a solar cell is provided, comprising: an N-type substrate, the N-type substrate comprising a first surface and a second surface opposite to each other, the first surface comprising a metal contact region and a non-metal contact region; an isolation structure, a doping structure, a first passivation layer and a plurality of first electrodes located on the first surface, wherein the doping structure comprises a first P-type doped emitter and a second P-type doped emitter, the second P-type doped emitter is located in the metal contact region, the isolation structure is located between two adjacent second P-type doped emitters, the isolation structure is used to isolate the first electrode from the N-type substrate, the first P-type doped emitter is located in the non-metal contact region, the first passivation layer is located in the non-metal contact region on a side of the doping structure away from the N-type substrate, and the first electrode is located in a side of the isolation structure away from the N-type substrate; a second tunneling dielectric layer, a second doped conductive layer, a second passivation layer and a plurality of second electrodes located on the second surface.

[0007] Furthermore, the isolation structure includes a stacked first doped conductive layer and a first tunneling dielectric layer, and the first doped conductive layer is located on a side of the first tunneling dielectric layer away from the N-type substrate.

[0008] Furthermore, the material of the first doped conductive layer is P-type amorphous silicon or P-type polycrystalline silicon, and the material of the first tunneling dielectric layer is silicon oxide.

[0009] Furthermore, the thickness of the first doped conductive layer is 1-2 nm, and the thickness of the first tunnel dielectric layer is 1-2 nm.

[0010] Furthermore, the doping concentration of the first doped conductive layer is less than or equal to the doping concentration of the second P-type doped emitter.

[0011] Furthermore, the doping concentration of the second P-type doped emitter is greater than the doping concentration of the first P-type doped emitter.

[0012] Furthermore, the second P-type doped emitter is also located in the non-metallic contact area.

[0013] Furthermore, the width of the portion of the second P-type doped emitter located in the metal contact area in the predetermined direction is a first width, the width of the portion of the second P-type doped emitter located in the non-metal contact area in the predetermined direction is a second width, the ratio of the first width to the second width is 0.9 to 1.1, and the predetermined direction is perpendicular to the thickness direction of the N-type substrate.

[0014] Furthermore, the width of the portion of the second P-type doped emitter located in the metal contact area in the predetermined direction is a first width, the width of the isolation structure in the predetermined direction is a third width, the first width is smaller than the third width, and the predetermined direction is perpendicular to the thickness direction of the N-type substrate.

[0015] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided a photovoltaic module, comprising: a cell string formed by connecting any one of the solar cells described above; a packaging layer for covering the surface of the cell string; and a cover plate for covering the surface of the packaging layer away from the cell string.

[0016] By applying the technical solution of the present invention, the above-mentioned solar cell includes an isolation structure located on the N-type substrate. On the one hand, the isolation structure can reduce the diffusion of metal ions of the first electrode to the N-type substrate, thereby reducing the content of metal ions diffused into the N-type substrate, reducing the generation of metal single substance, and avoiding the destruction of the N-type substrate, thereby solving the problem in the related art that the ions in the electrode diffuse to form metal single substance, which will destroy other structures of the battery and thus reduce the photoelectric conversion efficiency of the battery. On the other hand, since the material of the isolation structure has a certain optical absorption coefficient, when light is incident, part of the light will be absorbed by the isolation structure, thereby reducing the light absorption of the N-type substrate, resulting in optical absorption loss. In this solution, the positive projection of the isolation structure on the N-type substrate is located within the positive projection of the first electrode on the N-type substrate, which can make the isolation structure completely hidden under the first electrode, further reducing the optical absorption loss caused by the isolation structure, and improving the optical absorption efficiency of the solar cell, thereby improving the efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 A schematic structural diagram of a solar cell provided according to an embodiment of the present application is shown;

[0019] Figure 2 A schematic diagram of the structure of another solar cell provided according to an embodiment of the present application is shown;

[0020] Figure 3 A schematic structural diagram of a photovoltaic assembly provided according to an embodiment of the present application is shown.

[0021] The above drawings include the following reference numerals:

[0022] 10. N-type substrate; 11. Metal contact area; 12. Non-metal contact area; 13. Isolation structure; 131. First doped conductive layer; 132. First tunneling dielectric layer; 14. Doping structure; 141. First P-type doped emitter; 142. Second P-type doped emitter; 15. First passivation layer; 16. First electrode; 17. Second tunneling dielectric layer; 18. Second doped conductive layer; 19. Second passivation layer; 20. Second electrode; W1. First width; W2. Second width; W3. Third width; 40. Solar cell; 402. Conductive tape; 41. Encapsulation layer; 42. Cover plate. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes 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.

[0026] As introduced in the background technology, the efficiency of solar cells in the prior art is not ideal. In order to solve the above technical problems, the present application proposes a solar cell and a photovoltaic module.

[0027] Figure 1 Schematic diagram of the structure of a solar cell according to an embodiment of the present application. Figure 1 and Figure 2 As shown, including:

[0028] An N-type substrate 10, wherein the N-type substrate 10 comprises a first surface and a second surface opposite to each other, and the N-type substrate 10 comprises a metal contact region 11 and a non-metal contact region 12;

[0029] An isolation structure 13, a doping structure 14, a first passivation layer 15 and a plurality of first electrodes 16 located on the first surface, wherein the doping structure 14 includes a first P-type doped emitter 141 and a second P-type doped emitter 142, the second P-type doped emitter 142 is located in the metal contact region 11, the isolation structure 13 is located between two adjacent second P-type doped emitters 142, the isolation structure 13 is used to isolate the first electrode 16 from the N-type substrate 10, the first P-type doped emitter 141 is located in the non-metal contact region 12, the first passivation layer 15 is located on a side of the doping structure 14 in the non-metal contact region 12 away from the N-type substrate 10, and the first electrode 16 is located on a side of the isolation structure 13 away from the N-type substrate 10;

[0030] A second tunnel dielectric layer 17 , a second doped conductive layer 18 , a second passivation layer 19 and a plurality of second electrodes 20 are located on the second surface.

[0031] Specifically, the first surface of the N-type substrate can be the front side and the second surface can be the back side, or the first surface of the N-type substrate can be the back side and the second surface can be the front side, that is, the solar cell is a single-sided cell, the front side can be used as a light-receiving surface for receiving incident light, and the back side can be used as a backlight surface. The N-type substrate is doped with N-type doping elements, and the N-type doping elements can be any one of the V group elements such as phosphorus (P), bismuth (Bi), antimony (Sb) or arsenic (As). The metal contact area extends in a predetermined direction. It should be noted that the subsequent steps will also form a first electrode on the first surface of the N-type substrate (the upper surface when a person is facing the screen or paper), and the orthographic projection of the first electrode on the first surface of the N-type substrate is located in the metal contact area, that is, the metal contact area is the portion of the first surface corresponding to the first electrode. In the predetermined direction, the width of the metal contact area can be equal to the width of the first electrode, and the width of the metal contact area can also be greater than the width of the first electrode. The non-metal contact area is the area on the first surface other than the above-mentioned metal contact area. In some specific embodiments, the width of the metal area on the first surface in the predetermined direction is 1.5 to 2 times the width of the first electrode in the predetermined direction. In this way, when manufacturing the first electrode, the formable area of ​​the electrode is relatively large, and the requirements for manufacturing processes such as alignment are more relaxed.

[0032] In some embodiments, the solar cell is a TOPCON (Tunnel Oxide Passivated Contact) cell, or the solar cell is a bifacial cell, that is, the first surface and the second surface of the N-type substrate can both serve as light-receiving surfaces and can be used to receive incident light.

[0033] In some embodiments, the first surface and the second surface are both non-planar surfaces, and the non-planar surfaces can increase the internal reflection of the incident light, thereby further improving the utilization rate of the light by the solar cell. More specifically, the cross-section of the non-planar surface along the thickness direction of the N-type substrate is a line segment, and the line segment can include at least one of a straight line segment and a curved line segment, that is, the line segment can be composed of a straight line segment, or a curved line segment, or a curved line segment and a straight line segment. In the case where only straight line segments are composed, the line segment is composed of a plurality of straight line segments connected in sequence. In a specific embodiment, Figure 1 As shown, the cross section of the first surface along the thickness direction of the N-type substrate is sawtooth-shaped, that is, it is composed of a plurality of straight line segments connected in sequence.

[0034] The isolation structure of the present application may be a single-layer structure or a multi-layer structure. Those skilled in the art may set a suitable number of layers according to actual conditions to form an isolation structure. In addition, the material of the isolation structure of the present application may include one or more of silicon oxide, polycrystalline silicon and amorphous silicon. Those skilled in the art may select a suitable material according to actual conditions to form an isolation structure.

[0035] The above-mentioned doping structure can be obtained by diffusing and doping P-type ions on the surface portion of the N-type substrate, and the doped part of the N-type substrate is converted into a doping structure. Specifically, in some embodiments, the P-type doping element can be any one of the III group elements such as boron (B) element, aluminum (Al) element, gallium (Ga) element or indium (In) element. In addition, the doping concentration of the above-mentioned first P-type doped emitter is different from the doping concentration of the second P-type doped emitter. In other words, the doping concentration of the first P-type doped emitter is greater than the doping concentration of the second P-type doped emitter, or the doping concentration of the first P-type doped emitter is less than the doping concentration of the second P-type doped emitter. Those skilled in the art can set a suitable doping concentration according to actual conditions to form the above-mentioned first P-type doped emitter and the second P-type doped emitter.

[0036] The first passivation layer may be a single-layer structure or a stacked-layer structure, and the material of the first passivation layer may include one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon carbon nitride oxide, titanium oxide, hafnium oxide or aluminum oxide. The specific material and number of layers are not limited in this application, and those skilled in the art may set them according to actual conditions.

[0037] The above-mentioned first passivation layer has a plurality of first passivation parts arranged at intervals, and a first opening is provided between two adjacent first passivation parts. The above-mentioned first electrode is located in the above-mentioned first opening, and the first electrode is respectively in contact with the isolation structure and the second P-type doped emitter. The material of the first electrode may include one or more of aluminum, silver, gold, nickel, molybdenum or copper.

[0038] Specifically, the second tunnel dielectric layer is located between the second surface of the N-type substrate and the second doped conductive layer. The second tunnel dielectric layer can constitute a passivation contact layer together with the second doped conductive layer. The second tunnel dielectric layer is used to passivate the second surface of the N-type substrate, play a chemical passivation effect, and reduce interface states. The material of the second tunnel dielectric layer can be a dielectric material, for example, including any one of silicon oxide, magnesium fluoride, silicon oxide, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride or aluminum oxide, titanium oxide. The specific material is not limited in this application, and those skilled in the art can set it according to actual conditions.

[0039] The second doped conductive layer may be a single-layer structure or a multi-layer structure. In addition, the material of the second doped conductive layer may include one or more of polycrystalline silicon and amorphous silicon. The second passivation layer is located on the side of the second doped conductive layer away from the second tunnel dielectric layer. The second passivation layer may be a single-layer structure or a stacked-layer structure. The material of the second passivation layer may include one or more of silicon oxide, silicon nitride, silicon oxynitride, carbon nitride silicon oxide, titanium oxide, hafnium oxide or aluminum oxide. The specific materials and number of layers of the second doped conductive layer and the second passivation layer are not limited in this application, and those skilled in the art may set them according to actual conditions.

[0040] The second passivation layer has a plurality of second passivation parts arranged at intervals, a second opening is provided between two adjacent second passivation parts, the second electrode is located in the second opening, and the second electrode is in contact with the second doped conductive layer, and the material of the second electrode may include one or more of aluminum, silver, gold, nickel, molybdenum or copper. The present application does not limit the specific material of the second electrode, and those skilled in the art may select it according to actual conditions.

[0041] The solar cell of the present application includes an isolation structure located on an N-type substrate. On the one hand, the isolation structure can reduce the diffusion of metal ions of the first electrode to the N-type substrate, thereby reducing the content of metal ions diffused into the N-type substrate, reducing the generation of metal single substances, and avoiding the destruction of the N-type substrate, thereby solving the problem in the related art that the ions in the electrode diffuse to form metal single substances, which will destroy other structures of the battery and thus reduce the photoelectric conversion efficiency of the battery. On the other hand, since the material of the isolation structure has a certain optical absorption coefficient, when light is incident, part of the light will be absorbed by the isolation structure, thereby reducing the light absorption of the N-type substrate, resulting in optical absorption loss. In this solution, the positive projection of the isolation structure on the N-type substrate is located within the positive projection of the first electrode on the N-type substrate, which can make the isolation structure completely hidden under the first electrode, further reducing the optical absorption loss caused by the isolation structure, and improving the optical absorption efficiency of the solar cell, thereby improving the efficiency of the solar cell.

[0042] In a specific implementation of the present application, Figure 2As shown, the isolation structure 13 includes a stacked first doped conductive layer 131 and a first tunnel dielectric layer 132, wherein the first doped conductive layer 131 is located on a side of the first tunnel dielectric layer 132 away from the N-type substrate 10. Compared with the single-layer isolation structure 13, the first doped conductive layer in this solution can form a band bending on the surface of the N-type substrate, and the first tunnel dielectric layer can cause an asymmetric shift in the energy band on the surface of the N-type substrate, so that the potential barrier to the majority carriers (also called majority carriers) among the carriers is lower than the potential barrier to the minority carriers (also called minority carriers) among the carriers. Therefore, the majority carriers can easily perform quantum tunneling through the first tunnel dielectric layer, while the minority carriers are difficult to pass through the first tunnel dielectric layer, so as to realize the selective transmission of carriers. In addition, the first tunnel dielectric layer can play a chemical passivation effect, that is, due to the interface state defects at the interface between the N-type substrate and the first tunnel dielectric layer, the interface state density on the back of the N-type substrate is small, and the reduction of the interface state density will inhibit the recombination of photogenerated carriers, increase the fill factor, short-circuit current and open-circuit voltage of the solar cell, so as to improve the photoelectric conversion efficiency of the solar cell. In addition, the first doped conductive layer can play a field passivation effect, specifically, an electrostatic field pointing to the inside of the N-type substrate is formed on the surface of the N-type substrate, so that the minority carriers escape from the interface, thereby reducing the minority carrier concentration, so that the carrier recombination rate at the interface of the N-type substrate is reduced, thereby increasing the open circuit voltage, short-circuit current and fill factor of the solar cell, and further improving the photoelectric conversion efficiency of the solar cell.

[0043] Specifically, the doping type of the first doped conductive layer is opposite to the doping type of the N-type substrate, and the doping type of the second doped conductive layer is the same as the doping type of the N-type substrate, that is, the doping type of the first doped conductive layer is P-type, and the doping type of the second doped conductive layer is P-type. In addition, the thickness, density and uniformity of the first tunnel dielectric layer will affect the passivation quality. For the first doped conductive layer, after high-temperature annealing, its impurities diffuse into the N-type substrate, and the diffusion region formed under the first tunnel dielectric layer can achieve the regulation of carrier transport and recombination behavior.

[0044] In some embodiments, the material of the first tunnel dielectric layer may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide or magnesium fluoride. The material of the first doped conductive layer may include at least one of amorphous silicon, polycrystalline silicon or silicon carbide.

[0045] In a specific implementation method of the present application, the material of the above-mentioned first doped conductive layer is P-type amorphous silicon or P-type polycrystalline silicon, and the material of the above-mentioned first tunneling dielectric layer is silicon oxide. The use of silicon oxide material in the first tunneling dielectric layer can further reduce the interface state density between the N-type substrate and the first doped dielectric layer, effectively reduce the recombination probability of electrons and holes, and then provide high-quality chemical passivation to passivate the surface defects of the N-type substrate. The use of doped polycrystalline silicon or amorphous silicon material in the first doped conductive layer can better induce energy band bending, thereby providing field passivation. Combining the above-mentioned two passivation methods of chemical passivation and field passivation can further enhance the passivation effect of the isolation structure.

[0046] Specifically, in terms of manufacturing process, amorphous silicon materials and polycrystalline silicon materials can be grown at low temperatures through chemical vapor deposition and other technologies, which can simplify the manufacturing process and reduce manufacturing costs. Similarly, silicon oxide can reduce the interface state density between the silicon substrate and polycrystalline silicon through chemical passivation, effectively reducing the recombination probability of electrons and holes, thereby increasing the open circuit voltage of the battery.

[0047] In a specific implementation method of the present application, the thickness of the first doped conductive layer is 1 to 2 nm, and the thickness of the first tunnel dielectric layer is 1 to 2 nm. The thickness of the first doped conductive layer or the first tunnel dielectric layer should not be too thick. If the thickness of the first doped conductive layer is too thick, it may affect the overall thickness of the solar cell, thereby affecting the efficiency of the solar cell; if the thickness of the first tunnel dielectric layer is too thick, it may affect the quantum tunneling of majority carriers in the first tunnel dielectric layer, thereby affecting the selective transmission of carriers. The thickness of the first doped conductive layer or the first tunnel dielectric layer should not be too thin. If the thickness of the first doped conductive layer or the first tunnel dielectric layer is too thin, it may affect the isolation effect of the isolation structure. The thickness setting of the first doped conductive layer and the first tunnel dielectric layer can further ensure the isolation effect of the isolation structure and the requirements of thinness of the solar cell at the same time.

[0048] In practical applications, the thickness of the first doped conductive layer and the thickness of the first tunnel dielectric layer may be the same or different. The thickness of the first doped conductive layer may be 1nm to 1.2nm, 1.2nm to 1.4nm, 1.4nm to 1.6nm, 1.6nm to 1.8nm, and 1.8nm to 2nm. The thickness of the first tunnel dielectric layer may be 1nm to 1.2nm, 1.2nm to 1.4nm, 1.4nm to 1.6nm, 1.6nm to 1.8nm, and 1.8nm to 2nm.

[0049] In another embodiment of the present application, the doping concentration of the first doped conductive layer is less than or equal to the doping concentration of the second P-type doped emitter. The doping concentration of the first doped conductive layer should not be too high. In the case where the doping concentration of the first doped conductive layer is too high, the doped ions may enter the first tunneling oxide layer, causing damage to the structure of the first tunneling oxide layer, thereby affecting the passivation effect of the first tunneling oxide layer. Therefore, the doping concentration of the first doped conductive layer is less than or equal to the doping concentration of the second P-type doped emitter, which can further ensure that the transmission efficiency of the solar cell is high.

[0050] Specifically, the doping concentration of the first doped conductive layer is greater than the doping concentration in the N-type substrate to form a sufficiently high potential barrier on the other side of the N-type substrate so that majority carriers in the N-type substrate can pass through the first tunneling dielectric layer to the first doped conductive layer.

[0051] In some specific embodiments, the doping concentration of the second P-type doped emitter is greater than the doping concentration of the first P-type doped emitter. Such a doping concentration design can reduce the recombination of carrier surfaces caused by the high doping concentration, thereby ensuring a high life span of minority carriers, and further ensuring a high open circuit voltage and short circuit current of the battery, so that the photoelectric conversion efficiency of the solar cell is high; on the other hand, such a doping concentration design can reduce the problem of high contact resistance caused by low doping concentration, thereby ensuring a small contact resistance and a small opening voltage of the battery, and can also improve the photoelectric conversion efficiency; on the other hand, under the action of the concentration difference between the first emitter and the second emitter, the carriers can be transmitted to the N-type substrate faster, which is also conducive to the improvement of the photoelectric conversion efficiency. Therefore, such a concentration design makes the photoelectric conversion efficiency of the solar cell higher.

[0052] Specifically, the doping concentration of the first P-type doped emitter is 1E 14 ~9E 19 atom / cm 3 The doping concentration of the second P-type doped emitter is 1E 15 ~9E 20 atom / cm 3 .

[0053] In order to further meet the requirements of accurate overprinting of the first electrode and the second P-type doped emitter during the manufacturing process of the first electrode, in a specific implementation method of the present application, the second P-type doped emitter is also located in the non-metallic contact area. The second P-type doped emitter is arranged in the non-metallic contact area, which can reserve sufficient overprinting position for the first electrode, further ensuring the accuracy of the overprinting process of the first electrode.

[0054] In a specific implementation method of the present application, Figure 1As shown, the width of the portion of the second P-type doped emitter 142 located in the metal contact region 11 in the predetermined direction is the first width W1, the width of the portion of the second P-type doped emitter 142 located in the non-metal contact region 12 in the predetermined direction is the second width W2, the ratio of the first width W1 to the second width W2 is 0.9-1.1, and the predetermined direction is perpendicular to the thickness direction of the N-type substrate 10. The width of the second P-type doped emitter 142 in the metal contact region and the non-metal contact region is substantially the same, which can further ensure the direct contact effect of the second P-type doped emitter 142 with the first electrode 16 and the overprint effect of the first electrode 16 at the same time.

[0055] like Figure 1 As shown, the width of the second P-type doped emitter 142 located in the metal contact region 11 in the predetermined direction is the first width W1, and the width of the isolation structure 13 in the predetermined direction is the third width W3, and the first width W1 is smaller than the third width W3. The width of the isolation structure 13 is greater than the width of the second P-type doped emitter 142 located in the metal contact region 11, which can increase the area of ​​the isolation of the first electrode 16 and the N-type substrate 10, improve the carrier recombination loss between the interface of the first electrode 16 and the doping structure 14, and further enhance the passivation effect.

[0056] The above technical scheme of the present application can be used for full back electrode contact cells with busbar-free technology (0BB, Zero Busbar) or multi-busbar technology (MBB, MULTI-BUSBAR), full back electrode contact cells (IBC, Interdigitated Back Contact), full back contact cell solar cells (ABC, All Back Contact), composite passivated back contact cells (HPBC, Hybrid Passivated Back Contact), emitter back passivated cells (PERC, Passivated Emitter and Rear Cell), tunneling oxide passivated contact cells (TOPcon, Tnuuel Oxide Passivated contact), TOPcon-IBC cells, crystalline silicon heterojunction solar cells (HJT, Heterojunction with Intrinsic Thin-layer), perovskite stacked cells, flexible cells and other photovoltaic cells. Test the tunneling resistance or other arbitrary thin layer resistance.

[0057] In another typical embodiment of the present application, a photovoltaic cell is provided, such as Figure 3 As shown, the photovoltaic module includes:

[0058] A battery string is formed by connecting a plurality of solar cells 40 of any one of the above embodiments;

[0059] Specifically, two adjacent battery strings may be electrically connected via a conductive tape 402. In some embodiments, the electrodes of the same polarity of the solar cells 40 are oriented in the same direction, and the conductive tape 402 connects the electrodes of the different polarities of two adjacent solar cells 40. In other embodiments, the solar cells 40 may also be arranged according to electrodes of different polarities, that is, the electrodes of the adjacent plurality of battery cells are arranged in the order of the first polarity, the second polarity, and the first polarity, and the conductive tape 402 connects two adjacent battery cells on the same side. In some embodiments, there is no spacing between the battery cells, that is, the battery cells overlap each other.

[0060] The encapsulation layer 41 is used to cover the surface of the battery string;

[0061] Specifically, the encapsulation layer 41 includes a first encapsulation layer and a second encapsulation layer, the first encapsulation layer covers one of the front side or the back side of the solar cell string, and the second encapsulation layer covers the other of the front side or the back side of the solar cell string. Specifically, the material of the encapsulation layer 41 can be at least one of organic encapsulation films such as polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), polyethylene octene co-elastic (POE), or polyethylene terephthalate (PET). In practical applications, there is a gap between the first encapsulation layer and the second encapsulation layer before lamination, but after lamination, the first encapsulation layer and the second encapsulation layer jointly form the above encapsulation layer 41.

[0062] The cover plate 42 is used to cover the surface of the packaging layer 41 away from the battery string.

[0063] Specifically, the material of the cover plate 42 may include a material having a light-transmitting function such as glass or plastic. In addition, the surface of the cover plate 42 facing the encapsulation layer 41 may be a concave-convex surface, thereby increasing the utilization rate of the incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate is arranged opposite to the first encapsulation layer, and the second cover plate is arranged opposite to the second encapsulation layer.

[0064] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0065] 1. The solar cell of the present application includes an isolation structure located on an N-type substrate. On the one hand, the isolation structure can reduce the diffusion of metal ions of the first electrode to the N-type substrate, thereby reducing the content of metal ions diffused into the N-type substrate, reducing the generation of metal single substances, and avoiding the destruction of the N-type substrate, thereby solving the problem in the related art that the ions in the electrode diffuse to form metal single substances, which will destroy other structures of the battery and thus reduce the photoelectric conversion efficiency of the battery. On the other hand, since the material of the isolation structure has a certain optical absorption coefficient, when light is incident, part of the light will be absorbed by the isolation structure, thereby reducing the light absorption of the N-type substrate, resulting in optical absorption loss. In this solution, the orthographic projection of the isolation structure on the N-type substrate is located within the orthographic projection of the first electrode on the N-type substrate, which can make the isolation structure completely hidden under the first electrode, further reducing the optical absorption loss caused by the isolation structure, and improving the optical absorption efficiency of the solar cell, thereby improving the efficiency of the solar cell.

[0066] 2. The photovoltaic cell of the present application includes a battery string formed by connecting solar cells, and the solar cell includes an isolation structure located on an N-type substrate. On the one hand, the isolation structure can reduce the diffusion of metal ions of the first electrode to the N-type substrate, thereby reducing the content of metal ions diffused into the N-type substrate, reducing the generation of metal single substances, and avoiding the destruction of the N-type substrate, thereby solving the problem that the ions in the electrode diffuse to form metal single substances in the related art, which will destroy other structures of the battery and reduce the photoelectric conversion efficiency of the battery. On the other hand, since the material of the isolation structure has a certain optical absorption coefficient, when light is incident, part of the light will be absorbed by the isolation structure, thereby reducing the light absorption of the N-type substrate, resulting in optical absorption loss. In this solution, the positive projection of the isolation structure on the N-type substrate is located within the positive projection of the first electrode on the N-type substrate, which can make the isolation structure completely hidden under the first electrode, further reducing the optical absorption loss caused by the isolation structure, and improving the optical absorption efficiency of the solar cell, thereby improving the efficiency of the solar cell.

Claims

1. A solar cell, characterized in that: include: An N-type substrate, the N-type substrate comprising a first surface and a second surface opposite to each other, the first surface comprising a metal contact region and a non-metal contact region; an isolation structure, a doping structure, a first passivation layer, and a plurality of first electrodes located on the first surface, wherein the doping structure comprises a first P-type doped emitter and a second P-type doped emitter, the second P-type doped emitter is located in the metal contact region, the isolation structure is located between two adjacent second P-type doped emitters, the isolation structure is used to isolate the first electrode from the N-type substrate, the first P-type doped emitter is located in the non-metal contact region, the first passivation layer is located on a side of the doping structure in the non-metal contact region away from the N-type substrate, the first electrode is located on a side of the isolation structure away from the N-type substrate, the orthographic projection of the isolation structure on the N-type substrate is a first projection, the orthographic projection of the first electrode on the N-type substrate is a second projection, and the first projection is located in the second projection; A second tunneling dielectric layer, a second doped conductive layer, a second passivation layer and a plurality of second electrodes are located on the second surface.

2. The solar cell according to claim 1, characterized in that The isolation structure includes a stacked first doped conductive layer and a first tunneling dielectric layer, wherein the first doped conductive layer is located on a side of the first tunneling dielectric layer away from the N-type substrate.

3. The solar cell according to claim 2, characterized in that: The material of the first doped conductive layer is P-type amorphous silicon or P-type polycrystalline silicon, and the material of the first tunneling dielectric layer is silicon oxide.

4. The solar cell according to claim 2, characterized in that: The thickness of the first doped conductive layer is 1-2 nm, and the thickness of the first tunnel dielectric layer is 1-2 nm.

5. The solar cell according to claim 2, characterized in that: The doping concentration of the first doped conductive layer is less than or equal to the doping concentration of the second P-type doped emitter.

6. The solar cell according to claim 1, characterized in that The doping concentration of the second P-type doped emitter is greater than the doping concentration of the first P-type doped emitter.

7. The solar cell according to claim 1, characterized in that The second P-type doped emitter is also located in the non-metallic contact area.

8. The solar cell according to claim 7, characterized in that: The width of the portion of the second P-type doped emitter located in the metal contact area in a predetermined direction is a first width, the width of the portion of the second P-type doped emitter located in the non-metal contact area in the predetermined direction is a second width, the ratio of the first width to the second width is 0.9 to 1.1, and the predetermined direction is perpendicular to the thickness direction of the N-type substrate.

9. The solar cell according to claim 1, characterized in that: The width of the second P-type doped emitter located in the metal contact area in the predetermined direction is a first width, the width of the isolation structure in the predetermined direction is a third width, the first width is smaller than the third width, and the predetermined direction is perpendicular to the thickness direction of the N-type substrate.

10. A photovoltaic module, characterized in that: include: A battery string, formed by connecting the solar cells according to any one of claims 1 to 9; An encapsulation layer, used to cover the surface of the battery string; The cover plate is used to cover the surface of the packaging layer away from the battery string.

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