Photovoltaic cell, manufacturing method thereof and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a photovoltaic cell and a manufacturing method thereof, and a photovoltaic module, and the photovoltaic cell comprises a fragmented cell which is obtained through the cutting processing of a whole cell, and is provided with a cutting surface formed through the cutting processing; the passivation layer is located on the cutting surface, the material of the passivation layer comprises a metal oxide, and metal elements in the metal oxide comprise at least one of an Al element, a Ti element, a Zn element, a Zr element, an Hf element, a Mo element, a W element or a Ni element; and the protection layer is located on the side, away from the cutting face, of the passivation layer, the material of the protection layer comprises a nitride, and the nitride is composed of one of third main group elements and a nitrogen element. According to the photovoltaic cell, the manufacturing method thereof and the photovoltaic module provided by the embodiment of the invention, the photoelectric conversion efficiency of the photovoltaic cell comprising the fragmented cell is at least improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the photovoltaic field, and in particular to a photovoltaic cell and a manufacturing method thereof, and a photovoltaic module. Background Art

[0002] In order to reduce the power reduction and hot spots of photovoltaic modules caused by differences in battery electrical performance, the high current of the whole solar cell can easily lead to significant resistance loss. In order to improve the problem of large power loss of the whole solar cell, half-cell, shingled and other forms of photovoltaic modules are constantly favored by terminal module manufacturers and users.

[0003] However, whether it is a half-cell module or a shingled module, laser cutting technology is required to cut the entire solar cell into half or multiple small slices. The sliced ​​cells have reduced efficiency due to mechanical damage during the slicing process and the presence of hanging bonds on the cut surface, thereby reducing the module power. Summary of the invention

[0004] The embodiments of the present application provide a photovoltaic cell and a method for manufacturing the same, as well as a photovoltaic module, which are at least beneficial to improving the photoelectric conversion efficiency of a photovoltaic cell including a sliced ​​cell.

[0005] According to some embodiments of the present application, on the one hand, the embodiments of the present application provide a photovoltaic cell, including: a sliced ​​cell, the sliced ​​cell is obtained by cutting a whole cell, and the sliced ​​cell has a cutting surface formed by the cutting process; a passivation layer, the passivation layer is located on the cutting surface, the material of the passivation layer includes a metal oxide, the metal element in the metal oxide includes at least one of Al element, Ti element, Zn element, Zr element, Hf element, Mo element, W element or Ni element; a protective layer, the protective layer is located on a side of the passivation layer away from the cutting surface, the material of the protective layer includes a nitride, and the nitride is composed of an element of the third main group elements and nitrogen element.

[0006] In some embodiments, there is an intermediate layer between the passivation layer and the protective layer, and the material of the intermediate layer includes the same metal element as the metal oxide in the passivation layer, and the material of the intermediate layer includes the same third main group element as the nitride in the protective layer.

[0007] In some embodiments, in a direction perpendicular to the cutting plane, a ratio of a thickness of the passivation layer to a thickness of the protection layer is 0.7-2.

[0008] In some embodiments, the thickness of the protection layer along a direction perpendicular to the cutting surface is 10 nm to 100 nm.

[0009] In some embodiments, the passivation layer includes a first sub-passivation layer and a second sub-passivation layer, the first sub-passivation layer is located on the cutting surface, the second sub-passivation layer is located on the side of the first sub-passivation layer away from the cutting surface, the material of the first sub-passivation layer includes silicon oxide, and the material of the second sub-passivation layer includes metal oxide.

[0010] In some embodiments, the passivation layer further includes: a third sub-passivation layer, the third sub-passivation layer is located between the first sub-passivation layer and the second sub-passivation layer, the material of the third sub-passivation layer includes metal silicon oxide, and the metal element in the metal silicon oxide is the same as the metal element in the second sub-passivation layer.

[0011] In some embodiments, in a direction perpendicular to the cutting plane, a thickness of the protection layer is greater than or equal to a thickness of the second sub-passivation layer.

[0012] In some embodiments, the split battery has a first surface and a second surface disposed opposite to each other, the cut surface connects the first surface and the second surface, the protective layer extends to the first surface of the split battery, and / or the protective layer extends to the second surface of the split battery.

[0013] According to some embodiments of the present application, on the other hand, the embodiments of the present application provide a photovoltaic module, including: a battery string, the battery string includes at least one photovoltaic cell as in the above embodiments; an adhesive film, the adhesive film covers the surface of the battery string; and a cover plate, the cover plate covers the surface of the adhesive film away from the battery string.

[0014] According to some embodiments of the present application, on the other hand, the embodiments of the present application provide a method for manufacturing a photovoltaic cell, including: providing a whole cell; cutting the whole cell to form a plurality of sliced ​​cells, the sliced ​​cells having a cutting surface; forming a passivation layer on the cutting surface, the material of the passivation layer including a metal oxide, the metal element in the metal oxide including at least one of Al, Ti, Zn, Zr, Hf, Mo, W or Ni; forming a protective layer on the surface of the passivation layer away from the cutting surface, the material of the protective layer including a nitride, the nitride consisting of an element of the third main group elements and nitrogen.

[0015] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0016] In the photovoltaic cell provided in the embodiment of the present application, there is a passivation layer on the cut surface of the sliced ​​cell, the passivation layer comprises a metal oxide material, and the metal element in the metal oxide material comprises at least one of Al, Ti, Zn, Zr, Hf, Mo, W or Ni, and the metal element in the passivation layer makes the passivation layer itself have a high density of fixed charge to generate a large electric field, thereby performing good field effect passivation on the cut surface, so that a large band bending is generated between the passivation layer and the cut surface, hindering the migration of minority carriers to the cut surface, reducing the concentration of minority carriers at the cut surface, thereby facilitating the reduction of the recombination probability of majority carriers and minority carriers at the cut surface, and improving the efficiency of the photovoltaic cell comprising the sliced ​​cell. In addition, when only the passivation layer is located on the cut surface of the sliced ​​cell, if the metal oxide in the passivation layer is in contact with the air for a long time, it is easy to absorb water vapor in the air and adsorb particles in the air, which may lead to the failure of the passivation layer and cause the risk of reduced reliability of the photovoltaic cell. In the photovoltaic cell provided in the embodiment of the present application, a protective layer is provided on the surface of the passivation layer away from the cutting surface, and the material of the protective layer includes a nitride composed of an element of the third main group and a nitrogen element. For example, boron nitride, aluminum nitride, and gallium nitride are all atomic crystals. Therefore, boron nitride, aluminum nitride, and gallium nitride have high stability, can protect the inner passivation layer, avoid the problem of failure of the passivation layer due to long-term contact with air and water vapor, and improve the stability of the photovoltaic cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present application or the technical solutions in the traditional technology, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A top view of a whole battery provided in an embodiment of the present application, which is divided into two sub-batteries after cutting;

[0019] Figures 2 to 7 Schematic diagram of the cross-sectional structure of various photovoltaic cells provided in the embodiments of the present application;

[0020] Figure 8 A schematic diagram of the structure of a photovoltaic module provided in an embodiment of the present application;

[0021] Fig. 9 A flowchart corresponding to a method for manufacturing a photovoltaic cell provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] As known from the background art, the photoelectric conversion efficiency of solar cells after cutting needs to be improved.

[0023] The photovoltaic cell and the manufacturing method thereof and the photovoltaic module provided in the embodiments of the present application are at least beneficial to improving the photoelectric conversion efficiency of the photovoltaic cell including the sliced ​​cells.

[0024] In the description of the embodiments of the present application, the technical terms "first", "second", etc. 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 application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0025] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0027] In the description of the embodiments of the present application, technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0028] In the accompanying drawings corresponding to the embodiments of the present application, the thickness and area of ​​the layer are magnified for better understanding and ease of description. When describing a component on another component or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may be present between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as "substantially" 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 partial edge of the entire surface.

[0029] In the description of the embodiments of the present application, when a certain component “includes” another component, unless otherwise stated, other components are not excluded and other components may be further included.

[0030] The terms used in the description of the various described embodiments herein are used only to describe specific embodiments and are not intended to be limiting. As used in the description of the various described embodiments and the appended claims, "components" are also intended to include plural forms unless the context clearly indicates otherwise.

[0031] The following will describe the various embodiments of the present application in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present application, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in the present application can be implemented.

[0032] Figure 1 A top view of a whole battery provided in an embodiment of the present application, which is divided into two sub-batteries after cutting; Figure 2 A schematic diagram of the cross-sectional structure of the first photovoltaic cell provided in an embodiment of the present application. Figure 2 The Y-axis direction in Figure 1 The overlooking direction.

[0033] Combined with reference Figure 1 and Figure 2In some cases, the whole cell 100 has a first surface 110a and a second surface 110b arranged opposite to each other. After the whole cell 100 is cut once, the whole cell 100 is cut into two slice cells 110 arranged along the X-axis direction. The cut surface 110c formed by the cutting process on the slice cell 110 connects the first surface 110a and the second surface 110b. There are a large number of dangling bonds, mechanical damage caused by the cutting process or other surface defects on the cut surface 110c formed by the cutting process on the slice cell 110. Moreover, based on the various surface defects on the cut surface 110c, impurities are easily introduced on the cut surface 110c. These defects and impurities easily act as recombination centers of electron-hole pairs and shorten the life of carriers, resulting in a decrease in the photoelectric conversion efficiency of the slice cell 110. It should be noted that the cutting process includes but is not limited to laser cutting, and laser cutting is also prone to leave laser damage on the cut surface 110c.

[0034] refer to Figure 1 In some embodiments, the whole cell 100 can be any one of a PERC cell (Passivated Emitter and Rear Cell), a PERT cell (Passivated Emitter and Rear Totally-diffused cell), a TOPCon cell (Tunnel Oxide Passivated Contact), a HIT / HJT cell (Heterojunction Technology), or a BC cell (Back Contact). Correspondingly, the sliced ​​cell 110 can be any one of the above cells.

[0035] refer to Figure 1 In some embodiments, the whole cell 100 may be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell or a multi-compound solar cell, and the multi-compound solar cell may be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell or a perovskite solar cell. Correspondingly, the sliced ​​cell 110 may be any one of the above cells.

[0036] refer to Figure 2The photovoltaic cell provided in the embodiment of the present application includes: a slice cell 110, a passivation layer 111 and a protective layer 121. The slice cell 110 is obtained by cutting the whole cell, and the slice cell 110 has a cutting surface 110c formed by the cutting process; the passivation layer 111 is located on the cutting surface 110c, and the material of the passivation layer 111 includes a metal oxide, and the metal element in the metal oxide includes at least one of Al element, Ti element, Zn element, Zr element, Hf element, Mo element, W element or Ni element; the protective layer 121 is located on the side of the passivation layer 111 away from the cutting surface 110c, and the material of the protective layer 121 includes a nitride, and the nitride is composed of an element of the third main group elements and nitrogen element.

[0037] In the photovoltaic cell provided in the embodiment of the present application, a passivation layer 111 is provided on the cut surface 110c of the sliced ​​cell 110, and the passivation layer 111 comprises a metal oxide material, and the metal elements in the metal oxide material include at least one of Al element, Ti element, Zn element, Zr element, Hf element, Mo element, W element or Ni element. The metal elements in the passivation layer 111 make the passivation layer 111 itself have a high-density fixed charge to generate a large electric field, thereby performing good field effect passivation on the cut surface 110c, so that a large energy band bending is generated between the passivation layer 111 and the cut surface 110c, hindering the minority carriers from migrating to the cut surface 110c, and reducing the concentration of minority carriers at the cut surface 110c, which is beneficial to reducing the probability of recombination of majority carriers and minority carriers at the cut surface 110c, and improving the efficiency of the photovoltaic cell including the sliced ​​cell 110. In addition, when only the passivation layer 111 is located on the cut surface 110c of the split cell 110, if the metal oxide in the passivation layer 111 is in contact with the air for a long time, it is easy to absorb water vapor in the air and adsorb particles in the air, which may lead to the failure of the passivation layer 111, causing the risk of reduced reliability of the photovoltaic cell. In the photovoltaic cell provided by the embodiment of the present application, a protective layer 121 is provided on the surface of the passivation layer 111 away from the cut surface 110c. The material of the protective layer 121 includes a nitride composed of an element of the third main group element and nitrogen. For example, boron nitride, aluminum nitride, and gallium nitride are all atomic crystals. Boron nitride, aluminum nitride, and gallium nitride have high stability and can protect the inner passivation layer 111, avoiding the problem of failure of the passivation layer 111 due to long-term contact with air and water vapor, thereby improving the stability of the photovoltaic cell.

[0038] exist Figure 1 In the embodiment, the number of cutting processes is taken as one as an example. In this way, the whole battery 100 is divided into two battery slices 110. Each battery slice 110 has a cutting surface 110c. The drawings provided in this embodiment do not constitute a limitation on the number of cutting processes and the cutting method.

[0039] In a specific example, the number of cutting processes can also be 2 times, for example, the whole cell can be cross-cut to divide the whole cell into 4 slice cells, so that each slice cell has 2 intersecting cutting surfaces; or the cutting lines of the 2 cutting processes can be arranged in parallel to divide the whole cell into 3 slice cells, so that the slice cell located in the middle has 2 cutting surfaces, and the two slice cells located on both sides of the slice cell in the middle have 1 cutting surface. It can be understood that no matter whether the number of cutting surfaces of the slice cell is 1 or more, a passivation layer and a protective layer can be arranged on each cutting surface of the slice cell to passivate the cutting surface, and at the same time, the passivation layer is protected by the protective layer, thereby improving the efficiency of the photovoltaic cell and improving the stability of the photovoltaic cell.

[0040] In some embodiments, the metal element of the metal oxide material in the passivation layer 111 is Al, that is, the material of the passivation layer 111 is aluminum oxide. On the one hand, the aluminum oxide material enables the passivation layer 111 to have a high density of fixed negative charges (for example, Qf is about 10 12 cm -2 ~10 13 cm -2 ), which is beneficial to improve the field passivation effect on the cutting surface 110c, reduce the probability of carrier recombination at the cutting surface 110c, and thus help improve the photoelectric conversion efficiency of the slice battery 110; on the other hand, in the technology of forming the passivation layer 111 comprising aluminum oxide material, the passivation layer 111 will also have an appropriate amount of hydrogen ions, so that the passivation layer 111 has a good hydrogen passivation effect on the cutting surface 110c. The appropriate amount of hydrogen ions in the passivation layer 111 can not only effectively saturate the dangling bonds on the cutting surface 110c through migration, but also inhibit the recombination of itself with carriers, which is beneficial to ensure that the carriers are effectively converged to the corresponding electrodes in the slice battery 110, so as to further improve the photoelectric conversion efficiency of the slice battery 110.

[0041] In other embodiments, the metal element of the metal oxide material in the passivation layer 111 is the Mo element, that is, the material of the passivation layer 111 is molybdenum oxide. On the one hand, the molybdenum oxide material enables the passivation layer 111 to have a higher work function, which is also conducive to the passivation layer 111 having a good field passivation effect on the cut surface 110c; on the other hand, in the technology of forming the passivation layer 111 containing the molybdenum oxide material, the passivation layer 111 also has a proper amount of hydrogen ions, so that the passivation layer 111 has a good hydrogen passivation effect on the cut surface 110c.

[0042] It should be noted that the above two embodiments are examples of the metal oxide material in the passivation layer 111 having a good passivation effect on the cut surface 110c. In practical applications, the metal element in the metal oxide material includes at least one of the Al element, the Ti element, the Zn element, the Zr element or the Hf element, which can make the passivation layer 111 have a high density of fixed negative charges to perform a good field passivation effect on the cut surface 110c; the metal element in the metal oxide material includes at least one of the Mo element, the W element or the Ni element, which can make the passivation layer 111 have a high density of fixed positive charges or a high work function to perform a good field passivation effect on the cut surface 110c.

[0043] Figure 3 The cross-sectional structure diagram of the second photovoltaic cell provided in the embodiment of the present application. Figure 3 The Y-axis direction in Figure 1 The overlooking direction.

[0044] refer to Figure 3 In some embodiments, there is an intermediate layer 131 between the passivation layer 111 and the protective layer 121, and the material of the intermediate layer 131 includes the same metal element as the metal oxide in the passivation layer 111, and the material of the intermediate layer 131 includes the same third main group element as the nitride in the protective layer 121. The intermediate layer 131, as a transition layer between the passivation layer 111 and the protective layer 121, can help the contact interface between the passivation layer 111 and the protective layer 121 to have a good lattice adaptation, avoid the problem of increased defects in the cut surface 110c due to lattice mismatch, and thus maintain the passivation layer 111 with a good passivation effect.

[0045] In some cases, the protective layer 121 can be directly formed on the surface of the passivation layer 111, and the intermediate layer 131 can be formed by diffusion of metal elements in the passivation layer 111 into the protective layer 121, and diffusion of the third main group elements in the protective layer 121 into the passivation layer 111. In other cases, the intermediate layer 131 can be formed after the passivation layer 111 is formed and before the protective layer 121 is formed.

[0046] In some embodiments, in the direction perpendicular to the cutting surface 110c, the ratio of the thickness of the passivation layer 111 to the thickness of the protective layer 121 is 0.7 to 2, for example, it can be 0.7, 0.8, 0.9, 1, 1.3, 1.5, 1.8 or 2. On the one hand, the thickness of the protective layer 121 needs to be thick enough to provide sufficient protection for the passivation layer 111; on the other hand, too thick a thickness of the protective layer 121 does not increase the protection effect, but instead increases the cost of the photovoltaic cell. Therefore, the ratio of the thickness of the passivation layer 111 to the thickness of the protective layer 121 needs to be within an appropriate range to maintain the good protection effect of the protective layer 121 while avoiding an increase in the manufacturing cost of the photovoltaic cell.

[0047] In some specific examples, the thickness of the protective layer 121 in the direction perpendicular to the cutting surface 110c can be 10nm to 100nm, for example, 10nm, 15nm, 26nm, 35nm, 48nm, 56nm, 64nm, 73nm, 80nm, 92nm or 100nm.

[0048] In the above embodiments, the passivation layer 111 is taken as a single-layer structure as an example; in other embodiments, the passivation layer 111 may also be a multi-layer structure.

[0049] Figure 4 The cross-sectional structure diagram of the third photovoltaic cell provided in the embodiment of the present application. Figure 4 The Y-axis direction in Figure 1 The overlooking direction.

[0050] refer to Figure 4 In a specific example, the passivation layer 111 includes a first sub-passivation layer 141 and a second sub-passivation layer 151, the first sub-passivation layer 141 is located on the cutting surface 110c, and the second sub-passivation layer 151 is located on the side of the first sub-passivation layer 141 away from the cutting surface 110c, the material of the first sub-passivation layer 141 includes silicon oxide, and the material of the second sub-passivation layer 151 includes metal oxide.

[0051] The first sub-passivation layer 141 includes silicon oxide material, which can chemically passivate the cut surface 110c. For example, the oxygen atoms in the first sub-passivation layer 141 saturate the dangling bonds on the cut surface 110c, which can reduce the defect state density of the cut surface 110c, thereby reducing the recombination centers of the cut surface 110c and reducing the probability of carrier recombination. The second sub-passivation layer 151 comprises a metal oxide material, and the metal element in the metal oxide material comprises at least one of Al, Ti, Zn, Zr, Hf, Mo, W or Ni. With the help of the metal element in the second sub-passivation layer 151, the second sub-passivation layer 151 itself has a high-density fixed charge, and the high-density fixed charge can generate a large electric field, thereby performing good field effect passivation on the cut surface 110c, so that a large energy band bending is generated between the second sub-passivation layer 151 and the cut surface 110c, hindering the minority carriers from migrating to the cut surface 110c, reducing the concentration of the minority carriers at the cut surface 110c, thereby helping to reduce the recombination probability of the majority carriers and the minority carriers at the cut surface 110c. In this way, the first sub-passivation layer 141 and the second sub-passivation layer 151 cooperate with each other to significantly improve the photoelectric conversion efficiency of the sliced ​​cell 110, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0052] Figure 5 This is a schematic cross-sectional structure diagram of a fourth photovoltaic cell provided in an embodiment of the present application. Figure 5 The Y-axis direction in Figure 1 The overlooking direction.

[0053] refer to Figure 5 In a specific example, the passivation layer 111 includes: a first sub-passivation layer 141, a second sub-passivation layer 151 and a third sub-passivation layer 161, the third sub-passivation layer 161 is located between the first sub-passivation layer 141 and the second sub-passivation layer 151, and the material of the third sub-passivation layer 161 includes metal silicon oxide, and the metal element in the metal silicon oxide is the same as the metal element in the second sub-passivation layer 151. The third sub-passivation layer 161 plays a transition role to improve the adaptability of the lattice at the interface where the first sub-passivation layer 141, the third sub-passivation layer 161 and the second sub-passivation layer 151 are in contact with each other in sequence, and prevent the occurrence of gaps and dislocation phenomena at the interface where the first sub-passivation layer 141, the third sub-passivation layer 161 and the second sub-passivation layer 151 are in contact with each other in sequence, so as to improve the uniformity of the film layer of the passivation layer 111 itself, thereby improving the interface passivation effect of the passivation layer 111 on the sliced ​​battery 110. Moreover, it is helpful to improve the connection strength between the first sub-passivation layer 141 and the second sub-passivation layer 151 with the help of the third sub-passivation layer 161, so as to avoid the mutual slippage or falling off problem between the first sub-passivation layer 141 and the third sub-passivation layer 161, or the third sub-passivation layer 161 and the second sub-passivation layer 151, thereby helping to improve the structural stability of the passivation layer 111.

[0054] The third sub-passivation layer 161 not only has the same silicon element and oxygen element as the first sub-passivation layer 141, but also has the same metal element as the second sub-passivation layer 151, so that the third sub-passivation layer 161 serves as a transition layer between the first sub-passivation layer 141 and the second sub-passivation layer 151, and can also utilize the oxygen atoms in the third sub-passivation layer 161, based on the migration of these oxygen atoms toward the cutting surface 110c, to further saturate the dangling bonds on the cutting surface 110c, so as to further reduce the defect state density of the cutting surface 110c, thereby further reducing the recombination centers of the cutting surface 110c to reduce the probability of carrier recombination.

[0055] In some embodiments, in the direction from the first sub-passivation layer 141 to the second sub-passivation layer 151, the silicon content in the third sub-passivation layer 161 gradually decreases, and the metal content in the third sub-passivation layer 161 gradually increases. This is conducive to improving the performance stability of the third sub-passivation layer 161 and avoiding performance mutations caused by sudden changes in the element content in the third sub-passivation layer 161.

[0056] In some embodiments, the second sub-passivation layer 151 may be directly formed on the surface of the first sub-passivation layer 141, and the third sub-passivation layer 161 is formed by diffusion of metal elements in the second sub-passivation layer 151 into the first sub-passivation layer 141. In other embodiments, the third sub-passivation layer 161 is formed after the first sub-passivation layer 141 is formed and before the second sub-passivation layer 151 is formed.

[0057] In some embodiments, in a direction from the first subpassivation layer 141 to the second subpassivation layer 151 , the thickness of the first subpassivation layer 141 , the thickness of the third subpassivation layer 161 , and the thickness of the second subpassivation layer 151 increase sequentially.

[0058] It is worth noting that the first sub-passivation layer 141 includes silicon oxide material. When the thickness of the silicon oxide material is small, it can ensure that the first sub-passivation layer 141 has a good chemical passivation effect on the cutting surface 110c, and the formation process of the first sub-passivation layer 141 can be relatively simple. In addition, the thickness of the first sub-passivation layer 141 is small. When the third sub-passivation layer 161 includes oxygen elements, it is also beneficial to make the oxygen atoms in the third sub-passivation layer 161 easier to migrate to the cutting surface 110c, so as to further improve the chemical passivation effect on the cutting surface 110c. The third sub-passivation layer 161 serves as a transition layer between the first sub-passivation layer 141 and the second sub-passivation layer 151. The thickness of the third sub-passivation layer 161 is appropriate, and it is best to facilitate the migration of oxygen atoms in the third sub-passivation layer 161 to the cutting surface 110c. The second sub-passivation layer 151 includes a metal oxide material. The greater the film thickness of the metal oxide material, the better the field effect passivation effect on the cutting surface 110c. Therefore, the thickness of the second sub-passivation layer 151 is the largest among the three, the thickness of the first sub-passivation layer 141 is the smallest among the three, and the thickness of the third sub-passivation layer 161 is between the second sub-passivation layer 151 and the first sub-passivation layer 141. This can ensure that the first sub-passivation layer 141 has a good chemical passivation effect on the cutting surface 110c, and can also ensure that the second sub-passivation layer 151 has a good field effect passivation effect on the cutting surface 110c, and is beneficial to the migration of oxygen atoms in the third sub-passivation layer 161 to the cutting surface 110c.

[0059] In some specific embodiments, in the direction perpendicular to the cutting surface 110c, the thickness of the protective layer 121 is greater than or equal to the thickness of the second sub-passivation layer 151. The material of the second sub-passivation layer 151 is metal oxide. As the outermost layer of the passivation layer 111, if the metal oxide is in contact with the air for a long time, it is easy to absorb water vapor and adsorb particles in the air, which may lead to the failure of the passivation layer 111 and cause the risk of reduced reliability of the photovoltaic cell. The thickness of the protective layer 121 is at least greater than the thickness of the second sub-passivation layer 151, which can help the protective layer 121 to provide sufficient protection effect on the second sub-passivation layer 151 and improve the stability of the photovoltaic cell.

[0060] Figure 6 The cross-sectional structure diagram of the fifth photovoltaic cell provided in the embodiment of the present application. Figure 6 The Y-axis direction in Figure 1 The overlooking direction.

[0061] refer to Figure 6In some embodiments, the angle between the cutting surface 110c and the plane where the first surface 110a is located is an acute angle, and the angle between the cutting surface 110c and the plane where the second surface 110b is located is an obtuse angle. That is to say, the cutting surface 110c is inclined relative to the plane perpendicular to the first surface 110a or the second surface 110b, and the atomic arrangement density on the inclined cutting surface 110c is smaller, and the covalent bond surface density is smaller, so the connection between adjacent atoms on the cutting surface 110c is not firm, which is more conducive to promoting the passivation layer 111 located on the cutting surface 110c to form a bond with the dangling bonds on the cutting surface 110c, that is, making it easier for the passivation layer 111 to saturate the dangling bonds on the cutting surface 110c, and the passivation layer 111 can also passivate other surface defects on the cutting surface 110c, which is conducive to further improving the ability of the passivation layer 111 to reduce the defect state density of the cutting surface 110c, so as to further reduce the recombination center of the cutting surface 110c to reduce the probability of carrier recombination. In other words, designing the cutting surface 110c of the sliced ​​cell 110 to be relatively inclined rather than vertical and cooperating with the passivation function of the passivation layer 111 is beneficial to further improve the passivation effect of the passivation layer 111 on the cutting surface 110c, so as to further reduce the probability of carrier recombination on the cutting surface 110c, increase the life span of the carriers, and thus further improve the photoelectric conversion efficiency of the photovoltaic cell including the sliced ​​cell.

[0062] In some embodiments, the acute angle may be 45° to 80°, for example, 45°, 46°, 47°, 48°, 49°, 50°, 60°, 65°, 70°, 76° or 80°. In this way, the cut surface 110c may be close to the fcc (111) crystal plane of the split cell 110. Compared with other crystal planes, the atomic arrangement density of the fcc (111) crystal plane is the smallest, and the covalent bond surface density is the smallest, and the connection between adjacent atoms is not firm. Furthermore, the acute angle formed between the cutting surface 110c and the plane where the first surface 110a is located can be designed to be 45°~50°, which is beneficial to reduce the atomic arrangement density on the cutting surface 110c as much as possible, and enhance the ability of the passivation layer 111 to saturate the dangling bonds on the cutting surface 110c as much as possible, thereby helping to further enhance the passivation effect of the passivation layer 111 on the cutting surface 110c, so as to further reduce the probability of carrier recombination on the cutting surface 110c, and increase the lifetime of carriers, thereby further improving the photoelectric conversion efficiency of the photovoltaic cell including the segmented cell.

[0063] The corresponding obtuse angle is 100° to 135°, for example, 100°, 115°, 123°, 130° or 135°. It is understandable that the cutting surface 110c may not be a completely flat surface, that is, the obtuse angle and the acute angle may not be exactly complementary.

[0064] Figure 7This is a schematic cross-sectional structure diagram of the sixth photovoltaic cell provided in the embodiment of the present application. Figure 7 The Y-axis direction in Figure 1 The overlooking direction.

[0065] refer to Figure 7 In one example, the protective layer 121 may extend to the first side 110a and the second side 110b of the split battery 110. In another example, the protective layer 121 may extend only to the first side 110a of the split battery 110. In yet another example, the protective layer 121 may extend only to the second side 110b of the split battery 110.

[0066] Since the packaging materials of the photovoltaic modules formed based on the photovoltaic cells are difficult to achieve 100% isolation from the outside world, water vapor may enter the interior of the photovoltaic cells through the packaging materials or backplane used for edge sealing in a humid environment. At this time, the glass in the packaging material will produce sodium ions, and the sodium ions will move to the surface of the photovoltaic cell under the action of the external electric field to produce PID (Potential Induced Degradation), resulting in a decrease in the photoelectric conversion efficiency of the photovoltaic cell. The protective layer 121 extends to the first surface 110a of the sliced ​​cell 110, and / or the protective layer 121 extends to the second surface 110b of the sliced ​​cell 110, which can prevent water vapor from entering the cut surface 110c and entering the sliced ​​cell 110, thereby having a good anti-PID effect. In this way, even if the packaging materials of the photovoltaic module are difficult to achieve complete insulation, water vapor enters the environment where the photovoltaic cell is located through the packaging materials used for edge sealing, and the protective layer 121 can prevent the sodium ions in the glass in the packaging material from moving to the cut surface 110c, thereby preventing the PID phenomenon and maintaining a high photoelectric conversion rate of the photovoltaic cell.

[0067] In some embodiments, the width of the protective layer 121 extending from the edge of the split cell 110 to the center of the split cell 110 is 0-2 mm, for example, 0 mm, 0.15 mm, 0.44 mm, 0.56 mm, 0.72 mm, 0.95 mm, 1 mm, 1.2 mm, 1.6 mm, 1.8 mm or 2 mm. It is understood that when the width of the protective layer 121 extending from the edge of the split cell 110 to the center of the split cell 110 is too much, it is easy to cause the first surface 110a or the second surface 110b of the split cell 110 to be blocked by the protective layer 121, thereby reducing the light absorption efficiency of the photovoltaic cell. Therefore, the width of the protective layer 121 extending from the edge of the split cell 110 to the center of the split cell 110 needs to be within an appropriate range.

[0068] In the photovoltaic cell provided in the embodiment of the present application, a passivation layer 111 is provided on the cut surface 110c of the sliced ​​cell 110, and the passivation layer 111 comprises a metal oxide material, and the metal elements in the metal oxide material include at least one of Al element, Ti element, Zn element, Zr element, Hf element, Mo element, W element or Ni element. The metal elements in the passivation layer 111 make the passivation layer 111 itself have a high-density fixed charge to generate a large electric field, thereby performing good field effect passivation on the cut surface 110c, so that a large energy band bending is generated between the passivation layer 111 and the cut surface 110c, hindering the minority carriers from migrating to the cut surface 110c, and reducing the concentration of minority carriers at the cut surface 110c, which is beneficial to reducing the probability of recombination of majority carriers and minority carriers at the cut surface 110c, and improving the efficiency of the photovoltaic cell including the sliced ​​cell 110. In addition, when only the passivation layer 111 is located on the cut surface 110c of the split cell 110, if the metal oxide in the passivation layer 111 is in contact with the air for a long time, it is easy to absorb water vapor in the air and adsorb particles in the air, which may lead to the failure of the passivation layer 111, causing the risk of reduced reliability of the photovoltaic cell. In the photovoltaic cell provided by the embodiment of the present application, a protective layer 121 is provided on the surface of the passivation layer 111 away from the cut surface 110c, and the material of the protective layer 121 includes a nitride composed of an element of the third main group element and nitrogen, such as boron nitride, aluminum nitride, and gallium nitride are all atomic crystals, so boron nitride, aluminum nitride, and gallium nitride have high stability, can protect the inner passivation layer 111, avoid the problem of failure of the passivation layer 111 due to long-term contact with air and water vapor, and improve the stability of the photovoltaic cell.

[0069] Correspondingly, another embodiment of the present application further provides a photovoltaic assembly, including any photovoltaic cell in the above embodiments. The photovoltaic assembly provided in another embodiment of the present application will be described in detail below in conjunction with the accompanying drawings. For the parts that are the same or corresponding to the previous embodiment, reference can be made to the corresponding description of the previous embodiment, and will not be described in detail below.

[0070] Figure 8 A schematic diagram of the structure of a photovoltaic module provided in an embodiment of the present application.

[0071] refer to Figure 8 The photovoltaic module provided in the embodiment of the present application includes: a battery string, a film 203 and a cover plate 204, the battery string includes at least one photovoltaic cell 201 as in the above embodiment; the film 203 covers the surface of the battery string; the cover plate 204 covers the surface of the film 203 away from the battery string.

[0072] refer to Figure 8Adjacent photovoltaic cells 201 can be connected by welding strips 202, and multiple photovoltaic cells 201 can be electrically connected in series and / or in parallel. Based on the photovoltaic cells 201 in the above embodiment, the power loss of the photovoltaic module is improved by the current drop of the sliced ​​cells, so as to improve the photoelectric conversion efficiency of the photovoltaic module.

[0073] exist Figure 8 201, that is, the electrodes of the photovoltaic cells 201 with positive polarity are arranged toward the same side, and the welding strips 202 are respectively connected to different sides of two adjacent photovoltaic cells 201. In some embodiments, the photovoltaic cells may also be arranged in a manner such that the electrodes of the photovoltaic cells with different polarities face the same side, that is, the electrodes of the adjacent photovoltaic cells are arranged in the order of the first polarity, the second polarity, and the first polarity, and the welding strips connect the two adjacent photovoltaic cells on the same side.

[0074] In some embodiments, no spacing is provided between the photovoltaic cells, ie, the photovoltaic cells overlap each other.

[0075] The material of the film 203 can be an organic packaging film such as ethylene vinyl acetate copolymer (EVA) film, polyethylene octene elastomer (POE) film or polyvinyl butyral (PVB) film.

[0076] The cover plate 204 may be a glass cover plate, a plastic cover plate or other light-transmitting cover plate.

[0077] In some embodiments, the surface of the cover plate 204 facing the adhesive film 203 may be a concave-convex surface, thereby increasing the utilization rate of the incident light.

[0078] Accordingly, another embodiment of the present application further provides a method for manufacturing a photovoltaic cell, which is used to form the photovoltaic cell in the above embodiment. For the parts that are the same or corresponding to the previous embodiment, reference can be made to the corresponding description of the previous embodiment, and will not be described in detail below.

[0079] Fig. 9 A flowchart corresponding to a method for manufacturing a photovoltaic cell provided in an embodiment of the present application.

[0080] refer to Fig. 9 The method for manufacturing a photovoltaic cell provided in an embodiment of the present application comprises:

[0081] Step 301: Provide a whole battery.

[0082] In some embodiments, the whole cell may be any one of a PERC cell, a PERT cell, a TOPCon cell, a HIT / HJT cell or a BC cell.

[0083] In some embodiments, the entire cell can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell or a multi-compound solar cell. The multi-compound solar cell can specifically be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell or a perovskite solar cell.

[0084] Step 302: Cutting the whole battery to form a plurality of sliced ​​batteries, each of which has a cutting surface, wherein the cutting process includes but is not limited to laser cutting.

[0085] Step 303: forming a passivation layer on the cut surface, wherein the material of the passivation layer comprises metal oxide, and the metal element in the metal oxide comprises at least one of Al, Ti, Zn, Zr, Hf, Mo, W or Ni.

[0086] The process of forming the passivation layer includes but is not limited to a chemical vapor deposition process, a physical vapor deposition process or an atomic layer deposition process.

[0087] Step 304: forming a protective layer on the surface of the passivation layer away from the cutting surface, wherein the material of the protective layer includes nitride, and the nitride is composed of an element of the third main group elements and nitrogen.

[0088] The process of forming the protective layer includes but is not limited to a chemical vapor deposition process, a physical vapor deposition process or an atomic layer deposition process.

[0089] In some embodiments, the protective layer and the passivation layer can be formed in the same process step, and the material type of the corresponding protective layer and the material type of the passivation layer can be adjusted by adjusting the reaction gas source. Forming the protective layer and the passivation layer in the same process step can help improve the manufacturing efficiency of the photovoltaic cell.

[0090] In the manufacturing method of the photovoltaic cell provided in the embodiment of the present application, a passivation layer is formed on the cut surface of the sliced ​​cell, the passivation layer comprises a metal oxide material, and the metal element in the metal oxide material comprises at least one of Al, Ti, Zn, Zr, Hf, Mo, W or Ni, and the metal element in the passivation layer makes the passivation layer itself have a high density of fixed charge to generate a large electric field, thereby performing good field effect passivation on the cut surface, so that a large band bending is generated between the passivation layer and the cut surface, hindering the minority carriers from migrating to the cut surface, reducing the concentration of minority carriers at the cut surface, thereby facilitating the reduction of the recombination probability of majority carriers and minority carriers at the cut surface, and improving the efficiency of the photovoltaic cell comprising the sliced ​​cell. In addition, when only the passivation layer is located on the cut surface of the sliced ​​cell, if the metal oxide in the passivation layer is in contact with the air for a long time, it is easy to absorb water vapor in the air and adsorb particles in the air, which may lead to the failure of the passivation layer and cause the risk of reduced reliability of the photovoltaic cell. In the manufacturing method of the photovoltaic cell provided in the embodiment of the present application, a protective layer is also formed on the surface of the passivation layer away from the cutting surface. The material of the protective layer includes a nitride composed of an element of the third main group and a nitrogen element. For example, boron nitride, aluminum nitride, and gallium nitride are all atomic crystals. Therefore, boron nitride, aluminum nitride, and gallium nitride have high stability, can protect the inner passivation layer, avoid the problem of failure of the passivation layer due to long-term contact with air and water vapor, and improve the stability of the photovoltaic cell.

[0091] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes may be made to the embodiments in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present application, and therefore the scope of protection of the present application shall be subject to the scope defined in the claims.

Claims

1. A photovoltaic cell, characterized in that: include: Slice batteries, wherein the slice batteries are obtained by cutting a whole battery, and the slice batteries have cutting surfaces formed by the cutting process; a passivation layer, the passivation layer being located on the cutting surface, the material of the passivation layer comprising a metal oxide, the metal element in the metal oxide comprising at least one of Al, Ti, Zn, Zr, Hf, Mo, W or Ni; A protective layer is located at a side of the passivation layer away from the cutting surface, and a material of the protective layer includes nitride, and the nitride is composed of an element of the third main group elements and nitrogen.

2. The photovoltaic cell according to claim 1, characterized in that: An intermediate layer is provided between the passivation layer and the protective layer, and a material of the intermediate layer includes the same metal element as the metal oxide in the passivation layer, and a material of the intermediate layer includes the same third main group element as the nitride in the protective layer.

3. The photovoltaic cell according to claim 1, characterized in that: In a direction perpendicular to the cutting surface, a ratio of the thickness of the passivation layer to the thickness of the protection layer is 0.7-2.

4. The photovoltaic cell according to claim 3, characterized in that: In a direction perpendicular to the cutting surface, the thickness of the protective layer is 10 nm to 100 nm.

5. The photovoltaic cell according to claim 1, characterized in that: The passivation layer includes a first sub-passivation layer and a second sub-passivation layer, the first sub-passivation layer is located on the cutting surface, the second sub-passivation layer is located on a side of the first sub-passivation layer away from the cutting surface, the material of the first sub-passivation layer includes silicon oxide, and the material of the second sub-passivation layer includes the metal oxide.

6. The photovoltaic cell according to claim 5, characterized in that: The passivation layer further includes: a third sub-passivation layer, the third sub-passivation layer is located between the first sub-passivation layer and the second sub-passivation layer, the material of the third sub-passivation layer includes metal silicon oxide, and the metal element in the metal silicon oxide is the same as the metal element in the second sub-passivation layer.

7. The photovoltaic cell according to claim 5, characterized in that: In a direction perpendicular to the cutting plane, the thickness of the protection layer is greater than or equal to the thickness of the second sub-passivation layer.

8. The photovoltaic cell according to claim 1, characterized in that: The split battery has a first surface and a second surface that are oppositely disposed, the cutting surface connects the first surface and the second surface, the protective layer extends to the first surface of the split battery, and / or the protective layer extends to the second surface of the split battery.

9. A photovoltaic module, characterized in that: include: A battery string, the battery string comprising at least one photovoltaic cell according to any one of claims 1 to 8; An adhesive film, the adhesive film covering the surface of the battery string; A cover plate covers a surface of the adhesive film away from the battery string.

10. A method for manufacturing a photovoltaic cell, characterized in that: include: Provide whole battery; Cutting the whole battery to form a plurality of sliced ​​batteries, each of which has a cutting surface; forming a passivation layer on the cut surface, wherein the material of the passivation layer comprises a metal oxide, and the metal element in the metal oxide comprises at least one of Al, Ti, Zn, Zr, Hf, Mo, W or Ni; A protective layer is formed on a surface of the passivation layer away from the cutting surface. The material of the protective layer includes nitride. The nitride is composed of an element of the third main group elements and nitrogen.

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