Solar cell

Abstract

The embodiment of the utility model relates to the photovoltaic field, and provides a solar cell, which comprises a substrate, a doped conductive layer, a passivation laminated structure and a first electrode, and is characterized in that the substrate is provided with a first surface and a second surface which are opposite to each other, and the second surface comprises first areas and second areas which are alternately arranged; the doped conductive layer is located on the first region; the passivation laminated structure is located on the surface, deviating from the first surface, of the doped conductive layer and on the second region, and comprises a silicon oxide layer, a first silicon nitride layer, a first silicon oxynitride layer, a second silicon nitride layer, a second silicon oxynitride layer and a third silicon nitride layer which are stacked in sequence; the silicon oxide layer is positioned between the doped conductive layer and the first silicon nitride layer and is also positioned between the substrate and the first silicon nitride layer; the first electrode is on the first region and is in electrical contact with the doped conductive layer. The embodiment of the utility model at least can improve the performance of the solar cell.

Description

TECHNICAL FIELD

[0001] The embodiment of the present disclosure relates to the field of photovoltaics, in particular to a solar cell. BACKGROUND

[0002] Energy conservation is a topic of great concern in today's society, and the development and use of new environmentally friendly clean energy can greatly help to solve the global energy shortage problem. Solar energy is the most abundant energy resource in the world, and the use of solar energy and the development of efficient and stable solar cells can greatly alleviate the global energy crisis. In the future of science and technology development and production and life, solar cells will play an increasingly important role.

[0003] The passivation stack structure is included in the solar cell. However, the passivation stack structure in the solar cell has problems, which affects the passivation effect of the passivation stack structure and the performance of the solar cell. CONTENT OF THE INVENTION

[0004] The embodiment of the present disclosure provides a solar cell, which can at least improve the performance of the solar cell.

[0005] According to some embodiments of the present disclosure, the embodiment of the present disclosure provides a solar cell, comprising: a substrate, the substrate having opposite first and second surfaces, the second surface comprising first and second regions arranged alternately; a doped conductive layer, the doped conductive layer being on the first region; a passivation stack structure, the passivation stack structure being on the surface of the doped conductive layer away from the first surface and on the second region, the passivation stack structure comprising a silicon oxide layer, a first silicon nitride layer, a first silicon oxynitride layer, a second silicon nitride layer, a second silicon oxynitride layer and a third silicon nitride layer stacked in turn, the silicon oxide layer being between the doped conductive layer and the first silicon nitride layer, and also between the substrate and the first silicon nitride layer; a first electrode, the first electrode being on the first region and in electrical contact with the doped conductive layer.

[0006] In some embodiments, among the silicon oxide layer, the first silicon nitride layer, the first silicon oxynitride layer, the second silicon nitride layer, the second silicon oxynitride layer and the third silicon nitride layer, the third silicon nitride layer has the thickest thickness.

[0007] In some embodiments, the thickness of the silicon oxide layer is 1-5 nm, the thickness of the first silicon nitride layer is 7-13 nm, the thickness of the first silicon oxynitride layer is 7-13 nm, the thickness of the second silicon nitride layer is 12-18 nm, the thickness of the second silicon oxynitride layer is 12-18 nm, and the thickness of the third silicon nitride layer is 22-28 nm.

[0008] In some embodiments, the passivation stack structure further comprises: a fourth silicon nitride layer on a surface of the third silicon nitride layer away from the second silicon oxynitride layer; and a fifth silicon nitride layer on a surface of the fourth silicon nitride layer away from the third silicon nitride layer.

[0009] In some embodiments, among the silicon oxide layer, the first silicon nitride layer, the first silicon oxynitride layer, the second silicon nitride layer, the second silicon oxynitride layer, the third silicon nitride layer, the fourth silicon nitride layer, and the fifth silicon nitride layer, the fifth silicon nitride layer has the largest thickness.

[0010] In some embodiments, the thickness of the silicon oxide layer is 1-5 nm, the thickness of the first silicon nitride layer is 7-13 nm, the thickness of the first silicon oxynitride layer is 7-13 nm, the thickness of the second silicon nitride layer is 7-13 nm, the thickness of the second silicon oxynitride layer is 7-13 nm, the thickness of the third silicon nitride layer is 7-13 nm, the thickness of the fourth silicon nitride layer is 7-13 nm, and the thickness of the fifth silicon nitride layer is 12-18 nm.

[0011] In some embodiments, the refractive index of the third silicon nitride layer is greater than the refractive index of the fourth silicon nitride layer, and the refractive index of the fourth silicon nitride layer is greater than the refractive index of the fifth silicon nitride layer.

[0012] In some embodiments, the refractive index of the first silicon nitride layer is greater than the refractive index of the first silicon oxynitride layer, the refractive index of the first silicon oxynitride layer is greater than the refractive index of the second silicon nitride layer, the refractive index of the second silicon nitride layer is greater than the refractive index of the second silicon oxynitride layer, and the refractive index of the second silicon oxynitride layer is greater than the refractive index of the third silicon nitride layer.

[0013] In some embodiments, the total thickness of the passivation stack structure is 75-80 nm.

[0014] In some embodiments, the refractive index of the passivation stack structure is 2.05-2.25.

[0015] The technical solutions provided by the embodiments of the present disclosure have at least the following advantages:

[0016] In the technical solution of the solar cell provided in the embodiments of the present disclosure, the solar cell comprises a substrate, a doped conductive layer, a passivation stack structure and a first electrode, the substrate has opposite first and second surfaces, the second surface comprises first and second regions arranged alternately; the doped conductive layer is located on the first region; the passivation stack structure is located on the surface of the doped conductive layer away from the first surface and on the second region, the passivation stack structure comprises, in sequence, a silicon oxide layer, a first silicon nitride layer, a first silicon oxynitride layer, a second silicon nitride layer, a second silicon oxynitride layer and a third silicon nitride layer, the silicon oxide layer is located between the doped conductive layer and the first silicon nitride layer and also between the substrate and the first silicon nitride layer; and the first electrode is located on the first region and in electrical contact with the doped conductive layer.

[0017] The passivation stack structure comprises a silicon oxide layer, which is in direct contact with the doped conductive layer and the substrate. Compared with the technical solution of the prior art in which a silicon nitride layer is in direct contact with the doped conductive layer and the substrate, the silicon oxide layer has better interface contact with the substrate and the doped conductive layer, reduces the interface state density of the passivation stack structure and the substrate and the doped conductive layer, and reduces carrier recombination, thereby improving the passivation effect of the passivation stack structure and further improving the performance of the solar cell.

[0018] In addition, the passivation stack structure comprises a silicon oxynitride layer, which has good interface passivation performance and can compensate for the insufficient passivation effect of the silicon nitride layer, thereby improving the passivation effect of the passivation stack structure and improving the performance of the solar cell. The first silicon oxynitride layer is located between the first and second silicon nitride layers, and the second silicon oxynitride layer is located between the second and third silicon nitride layers. The first and second silicon oxynitride layers can act as stress buffer layers, reducing the stress concentration problem caused by the multilayer stacking of the first, second and third silicon nitride layers, and further improving the performance of the solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0019] One or more embodiments are illustrated by way of example in the drawings that are for illustrative purposes only, and not for the limitation of the embodiments, unless otherwise specifically stated, the drawings in the drawings do not constitute proportional limitation; in order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below, and obviously, the drawings in the following description can only be some embodiments of the present disclosure, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0020] Figure 1 is a cross-sectional structure schematic diagram of a solar cell structure in the related art;

[0021] Figure 2A cross-sectional structure schematic diagram of a solar cell provided by an embodiment of the present disclosure;

[0022] Figure 3 A bottom view of a solar cell provided by an embodiment of the present disclosure;

[0023] Figure 4 Another cross-sectional structure schematic diagram of a solar cell provided by an embodiment of the present disclosure;

[0024] Figure 5 A partial three-dimensional structure schematic diagram of a photovoltaic module provided by an embodiment of the present disclosure;

[0025] Figure 6 A cross-sectional structure schematic diagram of a solar cell provided by an embodiment of the present disclosure; Figure 5 A cross-sectional structure schematic diagram along the cross-sectional direction M1M2. DETAILED DESCRIPTION

[0026] Figure 1 A cross-sectional structure schematic diagram of a solar cell structure in the related art.

[0027] Reference Figure 1 The solar cell includes a substrate 100, a doped conductive layer 101, a passivation stack structure 102, and a first electrode 103. The substrate 100 has a first surface 110 and a second surface 120 opposite to each other, and the second surface 120 includes first regions 130 and second regions 140 arranged alternately. The doped conductive layer 101 is located on the first regions 130. The passivation stack structure 102 is located on the surface of the doped conductive layer 101 away from the first surface 110 and on the second regions 140. The passivation stack structure 102 includes a first silicon nitride layer 112, a second silicon nitride layer 122, and a third silicon nitride layer 132 stacked in sequence. The first silicon nitride layer 112 is located between the doped conductive layer 101 and the second silicon nitride layer 122, and also between the substrate 100 and the second silicon nitride layer 122. The first electrode 103 is located on the first regions 130 and in electrical contact with the doped conductive layer 101.

[0028] In the related art, in order to reduce the parasitic absorption of the doped conductive layer 101, the doped conductive layer 101 is only provided on the first regions 130, and the second regions 140 are not provided with the doped conductive layer 101. However, the passivation stack structure 102 still uses a stacked silicon nitride layer as the passivation stack structure 102, and the passivation effect is not good. For example, the first silicon nitride layer 112 on the first regions 130 will directly contact the substrate 100, and the direct contact between the first silicon nitride layer 112 and the substrate 100 is easy to produce interface defects, so that the carriers are more likely to recombine at the interface, thereby reducing the passivation effect of the passivation stack structure 102.

[0029] That is, in the related art solar cell, the passivation effect of the passivation stack structure 102 is poor, and the performance of the solar cell needs to be improved.

[0030] The embodiment of the present disclosure provides a solar cell, and the passivation stack structure includes a silicon oxide layer, the silicon oxide layer is in direct contact with a doped conductive layer and a substrate. Compared with the technical solution of the related art passivation stack structure in which a silicon nitride layer is in direct contact with the doped conductive layer and the substrate, the silicon oxide layer has better interface contact with the substrate and the doped conductive layer, reduces the interface state density of the passivation stack structure and the substrate and the doped conductive layer, reduces carrier recombination, and thus the passivation effect of the passivation stack structure can be improved, and the performance of the solar cell can be improved.

[0031] In addition, the passivation stack structure includes a silicon oxynitride layer, the silicon oxynitride layer has good interface passivation performance, can make up for the insufficient passivation effect of the silicon nitride layer, and thus the passivation effect of the passivation stack structure can be improved, and the performance of the solar cell can be improved. The first silicon oxynitride layer and the second silicon oxynitride layer can serve as a stress buffer layer, reduce the problem of stress concentration caused by the multilayer stacking of the first silicon nitride layer, the second silicon nitride layer and the third silicon nitride layer, and also improve the performance of the solar cell.

[0032] In the description of the embodiments of the present disclosure, the technical terms "first", "second", and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0033] In this document, the term "embodiment" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present disclosure. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor is it independent or alternative to other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0034] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are A, A and B, and B. In addition, the character " / " in this document generally represents a "or" relationship between the front and rear associated objects.

[0035] In the description of the embodiments of the present disclosure, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0036] In the description of the embodiments of the present disclosure, the orientation or positional relationship indicated by the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present disclosure.

[0037] In the description of the embodiments of the present disclosure, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0038] In the corresponding drawings of the embodiments of the present disclosure, in order to better understand and facilitate the description, the thickness and area of the layer are enlarged. When describing that a component (such as a layer, a film, a region or a substrate) is on or on the surface of another component, the component can be "directly" on the surface of the other component, or there can be a third component between the two components. On the contrary, when describing that a component is on the surface of another component or that a component surface is formed or provided with another component, it means that there is no third component between the two components. In addition, when describing that a component is "formed" on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a part of the edge of the entire surface.

[0039] In the description of the embodiments of the present disclosure, when a certain component "includes" another component, unless otherwise specified, other components are not excluded and other components can also be further included. In addition, when a layer, a film, a region or a plate and the like are referred to as "on / over" another component, it can be "directly on" another component (i.e. between the surface of another component and another component without other components), or another component can exist therebetween. In addition, when a layer, a film, a region, a plate and the like are "directly on" another component, or when a layer, a film, a region, a plate and the like are on the surface of another component, it means that there is no other component therebetween.

[0040] The embodiments of the present disclosure will be described in detail below with reference to the drawings. However, those skilled in the art can understand that, in the embodiments of the present disclosure, many technical details are presented in order to enable the reader to better understand the present disclosure. However, the technical solutions claimed by the present disclosure can be implemented even without these technical details and based on various changes and modifications of the following embodiments.

[0041] Figure 2 A schematic diagram of a cross-sectional structure of a solar cell provided by an embodiment of the present disclosure.

[0042] Reference Figure 2 The solar cell includes a substrate 200, a doped conductive layer 201, a passivation stack structure 202, and a first electrode 203. The substrate 200 has a first surface 210 and a second surface 220 opposite to each other, and the second surface 220 includes first regions 230 and second regions 240 arranged alternately. The doped conductive layer 201 is located on the first regions 230. The passivation stack structure 202 is located on a surface of the doped conductive layer 201 away from the first surface 210 and on the second regions 240. The passivation stack structure 202 includes a silicon oxide layer 212, a first silicon nitride layer 222, a first silicon oxynitride layer 232, a second silicon nitride layer 242, a second silicon oxynitride layer 252, and a third silicon nitride layer 262 stacked in sequence. The silicon oxide layer 212 is located between the doped conductive layer 201 and the first silicon nitride layer 222, and also between the substrate 200 and the first silicon nitride layer 222. The first electrode 203 is located on the first regions 230 and electrically contacts the doped conductive layer 201.

[0043] The substrate 200 provided by the embodiments of the present disclosure can be a silicon substrate, specifically, an N-type or P-type single crystal silicon substrate or a polycrystalline silicon substrate. The solar cell can be a passivated emitter rear cell (PERC), a tunnel oxide passivated contact (TOPCon), an interdigitated back contact (IBC), and the like, which are only examples and are not specifically limited.

[0044] The substrate 200 is used to receive incident light and generate photo-generated carriers. In some embodiments, the substrate 200 can be a semiconductor substrate.

[0045] In some embodiments, the material of the substrate 200 can be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, for example, can be silicon or germanium. Among them, the elemental semiconductor material can be single-crystalline, polycrystalline, amorphous or microcrystalline (a state having both single-crystalline and amorphous, referred to as microcrystalline), for example, silicon can be at least one of single-crystalline silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon.

[0046] In some embodiments, the material of the substrate 200 can also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenium and the like.

[0047] The substrate 200 can also be a sapphire substrate, a silicon-on-insulator substrate or a germanium-on-insulator substrate.

[0048] The substrate 200 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, which can be any one of a group V element such as phosphorus (P) element, bismuth (Bi) element, antimony (Sb) element or arsenic (As) element. The P-type semiconductor substrate is doped with a P-type element, which can be any one of a group III element such as boron (B) element, aluminum (Al) element, gallium (Ga) element or indium (In) element.

[0049] The substrate 200 has a first face 210 and a second face 220 opposite to each other. In some embodiments, the solar cell is a single-sided cell, and the first face 210 of the substrate 200 can be used as a light-receiving face to receive incident light, and the second face 220 can be used as a back light-receiving face. In some embodiments, the solar cell is a double-sided cell, and both the first face 210 and the second face 220 of the substrate 200 can be used as light-receiving faces to receive incident light. It can be understood that the back light-receiving face as referred to in the embodiments of the present application can also receive incident light, but the receiving degree of the incident light is weaker than that of the light-receiving face, and thus is defined as a back light-receiving face.

[0050] In some embodiments, a texturing process can be performed on at least one of the first face 210 or the second face 220 of the substrate 200 to form a textured surface on at least one of the first face 210 or the second face 220 of the substrate 200, so that the absorption and utilization rate of the incident light by the first face 210 and the second face 220 of the substrate 200 can be enhanced. In some embodiments, the textured surface can be a pyramid textured surface. As a common textured surface, the pyramid textured surface not only reduces the reflectivity of the surface of the substrate 200, but also forms a light trap to enhance the absorption of the incident light by the substrate 200 and improve the photoelectric conversion efficiency of the solar cell.

[0051] Specifically, if the solar cell is a single-sided cell, a textured surface, for example, a pyramidal textured surface, can be formed on the light-receiving surface of the substrate, and the back surface of the substrate can be a polished surface, i.e., the back surface of the substrate is flatter than the light-receiving surface. It should be noted that for a single-sided cell, a textured surface can also be formed on both the light-receiving surface and the back surface of the substrate.

[0052] If the solar cell is a double-sided cell, a textured surface can be formed on both the light-receiving surface and the back surface of the substrate.

[0053] The second surface 220 of the substrate 200 includes first regions 230 and second regions 240 arranged alternately, the first regions 230 are provided with the doped conductive layer 201, the passivation stack structure 202, and the first electrode 203. The second regions 240 are provided with the passivation stack structure 202.

[0054] It should be noted that the first regions 230 and the second regions 240 are artificially defined regions. The first regions 230 refer to the regions where the orthographic projection of the first electrode 230 on the substrate 200 is located, and the second regions 240 refer to the regions outside the orthographic projection of the first electrode 230 on the substrate 200. To ensure that the film layers contacted by the first electrode 230 have a large doping concentration or the regions contacted by the first electrode 230 are all high-concentration regions, thereby reducing the contact resistance, the area of the first regions 230 is generally greater than or equal to the area of the orthographic projection of the first electrode 230 on the substrate 200. In other words, the orthographic projection area of the first electrode 230 on the substrate 200 is smaller than the area of the first regions 230, and the orthographic projection position of the first electrode 230 on the substrate 200 must be within the first regions 230.

[0055] Figure 3 A bottom view of the solar cell provided by the embodiments of the present disclosure is shown. In order to better show the relationship between the doped conductive layer 201 and the first regions 230 and the second regions 240, Figure 3 The film layers other than the doped conductive layer 201 on the second surface 220 are not shown in the figure.

[0056] In combination with reference to Figure 2 and Figure 3 The doped conductive layer 201 is located on the first regions 230 of the second surface 220 of the substrate 200, and can form a band bending on the first regions 230 of the substrate 200 to realize the transport of carriers. The doped conductive layer 201 has parasitic absorption, and by providing the doped conductive layer 201 only on the first regions 230 of the second surface 220 and not providing the doped conductive layer 201 on the second regions 240, the parasitic absorption on the second surface 220 can be reduced, and the performance of the solar cell can be improved.

[0057] The doping element concentration in the doped conductive layer 201 is greater than the doping element concentration of the substrate 200, so as to form a high enough potential barrier at the second surface 220 of the substrate 200, which can induce the band bending of the second surface 220 of the substrate 200, realize the aggregation of the majority carriers (also known as majority carriers) and the depletion of the minority carriers (also known as minority carriers) at the second surface 220 of the substrate 200, and reduce the carrier recombination at the second surface 220 of the substrate 200.

[0058] The material of the doped conductive layer 201 can include at least one of amorphous silicon, polycrystalline silicon, or silicon carbide.

[0059] The doped conductive layer 201 can be doped with the same type of doping element as the substrate 200, for example, if the doping element type of the substrate 200 is P type, the doping element type in the doped conductive layer 201 can also be P type; if the doping element type of the substrate 200 is N type, the doping element type in the doped conductive layer 201 can also be N type.

[0060] In some embodiments, a tunneling layer 204 can also be arranged on the first region 230 of the substrate 200, and the tunneling layer 204 is located between the doped conductive layer 201 and the substrate 200.

[0061] The tunneling layer 204 can cause the band of the second surface 220 of the substrate 200 to be asymmetrically offset, so that the potential barrier to the majority carriers is lower than the potential barrier to the minority carriers. Therefore, the majority carriers can more easily quantum tunnel through the tunneling layer 204 to be transmitted into the doped conductive layer 201, while the minority carriers are difficult to pass through the tunneling layer 204, so as to realize the selective transmission of the carriers.

[0062] The tunneling layer 204 is arranged at the second surface 220 of the substrate 200, so that the tunneling layer 204 has a chemical passivation effect on the second surface 220 of the substrate 200, specifically: by saturating the dangling bonds of the second surface 220 of the substrate 200, reducing the defect state density of the second surface 220 of the substrate 200, and reducing the recombination center on the surface of the substrate 200 to reduce the carrier recombination rate.

[0063] In some embodiments, the material of the tunneling layer 204 can include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

[0064] The passivation stack structure 202 has a good passivation effect on the second surface 220 of the substrate 200, for example, can better chemically passivate the dangling bonds of the second surface 220 of the substrate 200, saturate the dangling bonds of the second surface 220 of the substrate 200, reduce the defect state density of the second surface 220 of the substrate 200, and inhibit the carrier recombination of the second surface 220 of the substrate 200.

[0065] In the passivation stack structure 202, the silicon oxide layer 212 is in direct contact with the doped conductive layer 201 and the substrate 200. Compared with the prior art passivation stack structure 202 which uses a silicon nitride layer in direct contact with the doped conductive layer 201 and the substrate 200, the silicon oxide layer 212 has better interface contact with the substrate 200 and the doped conductive layer 201, reduces the interface state density of the passivation stack structure 202 and the substrate 200 and the doped conductive layer 201, and reduces carrier recombination, thereby improving the passivation effect of the passivation stack structure 202 and improving the performance of the solar cell.

[0066] The passivation stack structure 202 includes a silicon oxynitride layer 212 which has good interface passivation performance and can compensate for the insufficient passivation effect of the silicon nitride layer, thereby improving the passivation effect of the passivation stack structure 202 and improving the performance of the solar cell. The first silicon oxynitride layer 232 is located between the first silicon nitride layer 222 and the second silicon nitride layer 242, and the second silicon oxynitride layer 252 is located between the second silicon nitride layer 242 and the third silicon nitride layer 262. The first silicon oxynitride layer 232 and the second silicon oxynitride layer 252 can act as a stress buffer layer to reduce the stress concentration problem caused by the multilayer stacking of the first silicon nitride layer 222, the second silicon nitride layer 242 and the third silicon nitride layer 262, and can also improve the performance of the solar cell.

[0067] In some embodiments, the total thickness of the passivation stack structure 202 is 75-80 nm, for example 75 nm, 76 nm, 77 nm, 78 nm, 79 nm or 80 nm. The total thickness of the passivation stack structure 202 in the above range can ensure the passivation effect of the passivation stack structure 202, while also avoiding light loss caused by excessive thickness of the passivation stack structure 202.

[0068] In some embodiments, the refractive index of the passivation stack structure 202 is 2.05-2.25, for example 2.05, 2.10, 2.15, 2.20 or 2.25. The refractive index of the passivation stack structure 202 in the above range can achieve effective coupling of light and improve the light absorption efficiency of the solar cell.

[0069] In some embodiments, among the silicon oxide layer 212, the first silicon nitride layer 222, the first silicon oxynitride layer 232, the second silicon nitride layer 242, the second silicon oxynitride layer 252 and the third silicon nitride layer 262, the third silicon nitride layer 262 has the thickest thickness. In other words, the third silicon nitride layer 262 on the outermost layer of the passivation stack structure 202 has the thickest thickness, and the thicker third silicon nitride layer 262 can provide better protection for other film layers in the passivation stack structure 202, thereby ensuring the passivation effect of the entire passivation stack structure 202.

[0070] In some embodiments, the thickness of the silicon oxide layer 212 is 1-5 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm, or 5 nm. The thickness of the first silicon nitride layer 222 is 7-13 nm, for example, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, or 13 nm. The thickness of the first silicon oxynitride layer 232 is 7-13 nm, for example, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, or 13 nm. The thickness of the second silicon nitride layer 242 is 12-18 nm, for example, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, or 18 nm. The thickness of the second silicon oxynitride layer 252 is 12-18 nm, for example, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, or 18 nm. The thickness of the third silicon nitride layer 262 is 22-28 nm, for example, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, or 28 nm. The thickness of each film layer in the passivation stack structure 202 is within the above range, which can achieve a good passivation effect on the substrate 200.

[0071] In some embodiments, the refractive index of the first silicon nitride layer 222 is greater than that of the first silicon oxynitride layer 232, the refractive index of the first silicon oxynitride layer 232 is greater than that of the second silicon nitride layer 242, the refractive index of the second silicon nitride layer 242 is greater than that of the second silicon oxynitride layer 252, and the refractive index of the second silicon oxynitride layer 252 is greater than that of the third silicon nitride layer 262. In this way, in the direction in which the first surface 210 points to the second surface 220, the refractive index of the passivation stack structure 202 decreases layer by layer, which can make the light propagate more smoothly in the passivation stack structure 202, further reduce the reflection loss, increase the propagation path and absorption probability of the light in the cell, and thus improve the performance of the solar cell.

[0072] Figure 4 Another cross-sectional structure diagram of a solar cell provided by the embodiments of the present disclosure.

[0073] Reference Figure 4 In some embodiments, the passivation stack structure 202 further includes a fourth silicon nitride layer 272 and a fifth silicon nitride layer 282, the fourth silicon nitride layer 272 is located on the surface of the third silicon nitride layer 262 away from the second silicon oxynitride layer 252, and the fifth silicon nitride layer 282 is located on the surface of the fourth silicon nitride layer 272 away from the third silicon nitride layer 262.

[0074] In some embodiments, among the silicon oxide layer 212, the first silicon nitride layer 222, the first silicon oxynitride layer 232, the second silicon nitride layer 242, the second silicon oxynitride layer 252, the third silicon nitride layer 262, the fourth silicon nitride layer 272, and the fifth silicon nitride layer 282, the fifth silicon nitride layer 282 has the largest thickness.

[0075] In some embodiments, the thickness of the silicon oxide layer 212 is 1-5 nm, the thickness of the first silicon nitride layer 222 is 7-13 nm, the thickness of the first silicon oxynitride layer 232 is 7-13 nm, the thickness of the second silicon nitride layer 242 is 7-13 nm, the thickness of the second silicon oxynitride layer 252 is 7-13 nm, the thickness of the third silicon nitride layer 262 is 7-13 nm, the thickness of the fourth silicon nitride layer 272 is 7-13 nm, and the thickness of the fifth silicon nitride layer 282 is 12-18 nm. When the thicknesses of the film layers in the passivation stack structure 202 are within the above ranges, the substrate 200 can be effectively passivated.

[0076] In some embodiments, the refractive index of the third silicon nitride layer 262 is greater than the refractive index of the fourth silicon nitride layer 272, and the refractive index of the fourth silicon nitride layer 272 is greater than the refractive index of the fifth silicon nitride layer 282. In other words, in the direction in which the first surface 210 points to the second surface 220, the refractive index of the three outermost silicon nitride layers in the passivation stack structure 202 decreases, which can make the light more smoothly refract when propagating in the three outermost silicon nitride layers, further reduce the reflection loss, increase the propagation path and absorption probability of the light in the cell, and improve the performance of the solar cell.

[0077] In some embodiments, the refractive index of the first silicon nitride layer 222 is greater than the refractive index of the first silicon oxynitride layer 232, the refractive index of the first silicon oxynitride layer 232 is greater than the refractive index of the second silicon nitride layer 242, the refractive index of the second silicon nitride layer 242 is greater than the refractive index of the second silicon oxynitride layer 252, the refractive index of the second silicon oxynitride layer 252 is greater than the refractive index of the third silicon nitride layer 262, the refractive index of the third silicon nitride layer 262 is greater than the refractive index of the fourth silicon nitride layer 272, and the refractive index of the fourth silicon nitride layer 272 is greater than the refractive index of the fifth silicon nitride layer 282. In this way, in the direction in which the first surface 210 points to the second surface 220, the refractive index of each film layer in the passivation stack structure 202 decreases layer by layer, which can make the light more smoothly refract when propagating in the passivation stack structure 202, further reduce the reflection loss, increase the propagation path and absorption probability of the light in the cell, and thus improve the performance of the solar cell.

[0078] In combination with reference to Figure 2 and Figure 4The first electrode 203 is located on the first region 230 of the second face 220, and the majority carriers in the substrate 200 tunnel into the doped conductive layer 201 through the tunneling layer 204, the majority carriers transferred into the doped conductive layer 201 are further transferred into the first electrode 203 in electrical contact with the doped conductive layer 201, and are collected by the first electrode 203.

[0079] The material of the first electrode 203 can be metal, for example, copper, silver, nickel, or aluminum, etc.

[0080] In some embodiments, the solar cell further comprises an emitter 205 located on the first face 210 of the substrate 200. In other embodiments, the emitter 205 can be located within the substrate 200.

[0081] The emitter 205 can be located on the entire surface of the first face 210. In some embodiments, the first face can comprise first regions and second regions arranged alternately, the emitter 205 on the first regions has a higher doping element concentration than the emitter 205 on the second regions, so as to form a selective emitter.

[0082] In some embodiments, the first face can comprise first regions and second regions arranged alternately, and the emitter 205 is located only on the first regions. The first regions can be arranged opposite to the first regions, and the second regions can be arranged opposite to the second regions; or the first regions and the first regions can be staggered, and the second regions and the second regions can be staggered.

[0083] The emitter 205 has a doping element type opposite to that of the substrate 200, and forms a PN junction with the substrate 200.

[0084] In some embodiments, the material of the emitter 205 is the same as that of the substrate 200.

[0085] The solar cell can further comprise a passivation layer 206. The passivation layer 206 is located on the surface of the first face 210 away from the emitter 205. The passivation layer 206 has a good passivation effect on the substrate 200, reduces the defect state density of the first face 210 of the substrate 200, and better inhibits the carrier recombination of the first face 210 of the substrate 200.

[0086] The passivation layer 206 also has a good antireflection effect, reduces the reflection of the first face 210 of the substrate 200 to the incident light, and improves the utilization rate of the substrate 200 to the incident light.

[0087] The material of the passivation layer 206 can be at least one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0088] In some embodiments, the passivation layer 206 can be a single layer structure. In some embodiments, the passivation layer 206 can also be a multi-layer structure, the materials of the layers in the multi-layer structure can be different from each other, or the materials of a part of the number of layers can be different from each other, and the materials of the remaining part of the number of layers can be the same. For example, the passivation layer 206 can be a multi-layer structure of a silicon nitride layer and an aluminum oxide layer.

[0089] The solar cell further includes a second electrode 207 in electrical contact with the emitter 205.

[0090] In some embodiments, the material of the second electrode 207 can be a metal, for example, can be copper, silver, nickel, or aluminum, etc.

[0091] In the above-mentioned solar cell, the passivation stack structure 202 includes a silicon oxide layer 212 in direct contact with the doped conductive layer 201 and the substrate 200. Compared with the prior art technical solution of using a silicon nitride layer in direct contact with the doped conductive layer 201 and the substrate 200, the silicon oxide layer 212 has better interface contact with the substrate 200 and the doped conductive layer 201, thereby improving the passivation effect of the passivation stack structure 202, and further improving the performance of the solar cell. In addition, the passivation stack structure 202 includes a silicon oxynitride layer 212, which has good interface passivation performance and can improve the performance of the solar cell. The first silicon oxynitride layer 232 and the second silicon oxynitride layer 252 can act as a stress buffer layer to reduce the problem of stress concentration caused by the multi-layer stacking of the first silicon nitride layer 222, the second silicon nitride layer 242, and the third silicon nitride layer 262, and can also improve the performance of the solar cell.

[0092] The embodiments of the present disclosure also provide a photovoltaic module, which includes a plurality of photovoltaic cells as provided in any of the preceding embodiments, or a plurality of stack cells as provided in the preceding embodiments, and is connected to form a photovoltaic module for converting received light energy into electrical energy. It should be noted that the same or corresponding parts as the preceding embodiments can refer to the corresponding description of the preceding embodiments, which will not be repeated here.

[0093] Figure 5 A partial perspective structure schematic diagram of the photovoltaic module provided in the embodiments of the present disclosure is shown in FIG. 8; Figure 6 A partial perspective structure schematic diagram of the photovoltaic module provided in the embodiments of the present disclosure is shown in FIG. 8; Figure 5 A cross-sectional structure schematic diagram along the cross-sectional direction M1M2 is shown in FIG. 9.

[0094] For better understanding of the present disclosure, reference will be made to the following drawings in combination with the specific embodiments of the present disclosure. Figure 5 And Figure 6The photovoltaic module comprises: a cell string connected by a plurality of solar cells 20 provided in the foregoing embodiments; an encapsulation film 21 for covering the surface of the cell string; and a cover plate 22 for covering the surface of the encapsulation film 21 away from the cell string. The solar cells 20 are electrically connected in a whole piece or multiple pieces to form a plurality of cell strings, and the plurality of cell strings are electrically connected in series and / or in parallel.

[0095] In some embodiments, the solar cell 20 comprises a TOPCon cell. In addition, the solar cell 20 can be a whole piece cell or a sliced cell, where the sliced cell refers to a cell formed by cutting a whole piece cell.

[0096] In some embodiments, the plurality of cell strings can be electrically connected through a conductive ribbon 23. Figure 5 Only the positional relationship between photovoltaic cells is shown, that is, the arrangement direction of the electrodes with the same polarity of the cell pieces is the same, or in other words, the electrodes with the positive polarity of each cell piece are arranged on the same side, so that the conductive ribbon connects the different sides of two adjacent cell pieces. In some embodiments, the cell pieces can also be arranged according to the electrodes with different polarities facing the same side, that is, the electrodes of the adjacent cell pieces are sequentially arranged in the order of the first polarity, the second polarity, and the first polarity, and then the conductive ribbon connects two adjacent cell pieces on the same side.

[0097] In some embodiments, no spacing is provided between the cell pieces, that is, the cell pieces overlap each other.

[0098] In some embodiments, the encapsulation film 21 comprises a first encapsulation layer and a second encapsulation layer, the first encapsulation layer covers one of the front surface or the back surface of the solar cell 20, and the second encapsulation layer covers the other of the front surface or the back surface of the solar cell 20. Specifically, at least one of the first encapsulation layer or the second encapsulation layer can be an organic encapsulation film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene copolymer elastomer (POE) film, or a polyethylene terephthalate (PET) film.

[0099] In some cases, the first encapsulation layer and the second encapsulation layer have a boundary line before lamination. After the lamination process, the photovoltaic module is formed, and there is no longer a concept of the first encapsulation layer and the second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 21.

[0100] In some embodiments, the cover plate 22 can be a glass cover plate, a plastic cover plate, or the like cover plate having a light transmission function. Specifically, the surface of the cover plate 22 facing the encapsulation adhesive film 21 can be a concave-convex surface, thereby increasing the utilization rate of incident light. The cover plate 22 includes a first cover plate opposite the first encapsulation layer and a second cover plate opposite the second encapsulation layer.

[0101] It can be understood by those skilled in the art that the above-mentioned embodiments are specific embodiments for realizing the present disclosure, and in actual application, various changes can be made in form and details without departing from the spirit and scope of the present disclosure. Any person skilled in the art can make various modifications and modifications without departing from the spirit and scope of the present disclosure, and therefore the protection scope of the present disclosure should be limited by the scope defined in the claims.

Claims

1. A solar cell, characterized by, The substrate has opposite first and second faces, the second face including first and second regions arranged alternately; a doped conductive layer on the first regions; a passivation stack structure on a surface of the doped conductive layer facing away from the first face and on the second regions, the passivation stack structure including, in order, a silicon oxide layer, a first silicon nitride layer, a first silicon oxynitride layer, a second silicon nitride layer, a second silicon oxynitride layer, and a third silicon nitride layer, the silicon oxide layer being between the doped conductive layer and the first silicon nitride layer and between the substrate and the first silicon nitride layer; a first electrode on the first regions and in electrical contact with the doped conductive layer. Among the silicon oxide layer, the first silicon nitride layer, the first silicon oxynitride layer, the second silicon nitride layer, the second silicon oxynitride layer, and the third silicon nitride layer, the third silicon nitride layer has the greatest thickness.

2. The solar cell according to claim 1, characterized in that, The thickness of the silicon oxide layer is 1-5 nm, the thickness of the first silicon nitride layer is 7-13 nm, the thickness of the first silicon oxynitride layer is 7-13 nm, the thickness of the second silicon nitride layer is 12-18 nm, the thickness of the second silicon oxynitride layer is 12-18 nm, and the thickness of the third silicon nitride layer is 22-28 nm.

3. The solar cell according to claim 2, characterized in that, The passivation stack structure further includes:

4. The solar cell of claim 1, wherein a fourth silicon nitride layer on a surface of the third silicon nitride layer facing away from the second silicon oxynitride layer; a fifth silicon nitride layer on a surface of the fourth silicon nitride layer facing away from the third silicon nitride layer. Among the silicon oxide layer, the first silicon nitride layer, the first silicon oxynitride layer, the second silicon nitride layer, the second silicon oxynitride layer, the third silicon nitride layer, the fourth silicon nitride layer, and the fifth silicon nitride layer, the fifth silicon nitride layer has the greatest thickness.

5. The solar cell according to claim 4, characterized in that, The thickness of the silicon oxide layer is 1-5 nm, the thickness of the first silicon nitride layer is 7-13 nm, the thickness of the first silicon oxynitride layer is 7-13 nm, the thickness of the second silicon nitride layer is 7-13 nm, the thickness of the second silicon oxynitride layer is 7-13 nm, the thickness of the third silicon nitride layer is 7-13 nm, the thickness of the fourth silicon nitride layer is 7-13 nm, and the thickness of the fifth silicon nitride layer is 12-18 nm.

6. The solar cell according to claim 5, characterized in that, The refractive index of the third silicon nitride layer is greater than the refractive index of the fourth silicon nitride layer, and the refractive index of the fourth silicon nitride layer is greater than the refractive index of the fifth silicon nitride layer.

7. The solar cell of claim 4, wherein, The refractive index of the first silicon nitride layer is greater than the refractive index of the first silicon oxynitride layer, the refractive index of the first silicon oxynitride layer is greater than the refractive index of the second silicon nitride layer, the refractive index of the second silicon nitride layer is greater than the refractive index of the second silicon oxynitride layer, and the refractive index of the second silicon oxynitride layer is greater than the refractive index of the third silicon nitride layer.

8. The solar cell according to claim 1 or 7, characterized in that, The total thickness of the passivation stack structure is 75-80 nm.

9. The solar cell of claim 1, wherein, ​ 10. The solar cell of claim 1, wherein, The passivation stack has a refractive index of 2.05 to 2.25.

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