Photovoltaic cell and method of manufacturing the same, and photovoltaic module

Abstract

The embodiment of the present application relates to the field of photovoltaics, and provides a photovoltaic cell and a manufacturing method thereof, and a photovoltaic module, the photovoltaic cell comprising: a split cell, the split cell being obtained by cutting a whole cell, the split cell having a cutting surface formed by the cutting; a passivation layer, the passivation layer being located at the cutting surface, a material of the passivation layer comprising a metal oxide, a metal element in the metal oxide comprising at least one of Al element, Ti element, Zn element, Zr element, Hf element, Mo element, W element or Ni element; and a protective layer, the protective layer being located at a side of the passivation layer away from the cutting surface, a material of the protective layer comprising a nitride, the nitride being composed of one element in the third main group and nitrogen element. The photovoltaic cell and the manufacturing method thereof and the photovoltaic module provided by the embodiment of the present application are at least beneficial to improving photoelectric conversion efficiency of the photovoltaic cell containing the split cell.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and in particular to a photovoltaic cell, a method for manufacturing the same, and a photovoltaic module. Background Technology

[0002] To reduce issues such as power reduction and hot spots in photovoltaic modules caused by differences in battery electrical performance, the high current of a whole solar cell can easily lead to significant resistance loss. To improve the problem of large power loss in whole solar cells, photovoltaic modules in the form of half-cell and shingled modules are increasingly favored by end-module manufacturers and users.

[0003] However, both half-cell and shingled modules require laser cutting technology to slice the entire solar cell into one or more smaller slices. The slicing process causes mechanical damage and dangling bonds in the cut surfaces, leading to a decrease in cell efficiency and consequently reducing the module's power output. Summary of the Invention

[0004] This application provides a photovoltaic cell, a method for manufacturing the same, and a photovoltaic module, which at least helps to improve the photoelectric conversion efficiency of a photovoltaic cell containing sectional cells.

[0005] According to some embodiments of this application, one aspect of this application provides a photovoltaic cell, including: a segmented cell, which is obtained by cutting a whole cell, and the segmented cell has a cut surface formed by the cutting process; a passivation layer, which is located on the cut surface, and the material of the passivation layer includes a metal oxide, wherein the metal element in the metal oxide includes at least one of Al, Ti, Zn, Zr, Hf, Mo, W or Ni; and a protective layer, which is located on the side of the passivation layer away from the cut surface, and the material of the protective layer includes a nitride, wherein the nitride is composed of an element from Group III and nitrogen.

[0006] In some embodiments, an intermediate layer is provided between the passivation layer and the protective layer, the material of the intermediate layer comprising the same metal element as the metal oxide in the passivation layer, and the material of the intermediate layer comprising the same Group 3 element as the nitride in the protective layer.

[0007] In some embodiments, the ratio of the thickness of the passivation layer to the thickness of the protective layer is 0.7 to 2 in the direction perpendicular to the cutting surface.

[0008] In some embodiments, the thickness of the protective layer is 10 nm to 100 nm in the direction perpendicular to the cut surface.

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

[0010] In some embodiments, the passivation layer further includes a third sub-passivation layer, which is located between the first and second sub-passivation layers, and the material of the third sub-passivation layer includes a metal silicon oxide, wherein 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, the thickness of the protective layer is greater than or equal to the thickness of the second sub-passivation layer in the direction perpendicular to the cut surface.

[0012] In some embodiments, the cell has a first side and a second side disposed opposite to each other, a cut surface connecting the first side and the second side, a protective layer extending to the first side of the cell, and / or, the protective layer extending to the second side of the cell.

[0013] According to some embodiments of this application, another aspect of this application provides a photovoltaic module, including: a battery string, the battery string including at least one photovoltaic cell as described in the above embodiments; an encapsulating film covering the surface of the battery string; and a cover plate covering the surface of the encapsulating film away from the battery string.

[0014] According to some embodiments of this application, another aspect of this application provides a method for manufacturing a photovoltaic cell, comprising: providing a whole cell; cutting the whole cell to form multiple segmented cells, each segmented cell having a cut surface; forming a passivation layer on the cut surface, the passivation layer being made of a metal oxide, wherein the metal element in the metal oxide is at least one of Al, Ti, Zn, Zr, Hf, Mo, W, or Ni; and forming a protective layer on the surface of the passivation layer away from the cut surface, the protective layer being made of a nitride, wherein the nitride is composed of one element from Group III and nitrogen.

[0015] The technical solution provided in this application has at least the following advantages:

[0016] In the photovoltaic cell provided in this application embodiment, a passivation layer is provided on the cut surface of the segmented cell. The passivation layer comprises a metal oxide material, and the metal element in the metal oxide material includes at least one of Al, Ti, Zn, Zr, Hf, Mo, W, or Ni. The metal element in the passivation layer gives the passivation layer itself a high density of fixed charge, thereby generating a large electric field. This effectively passivates the cut surface through the field effect, resulting in a large band bending between the passivation layer and the cut surface. This hinders the migration of minority carriers to the cut surface, reduces the concentration of minority carriers at the cut surface, and thus helps to reduce the recombination probability of majority and minority carriers at the cut surface, improving the efficiency of the photovoltaic cell containing the segmented cell. Furthermore, when only the passivation layer is located on the cut surface of the segmented cell, if the metal oxide in the passivation layer is in long-term contact with air, it is prone to absorbing moisture and adsorbing airborne particles, which may lead to the failure of the passivation layer and reduce the reliability of the photovoltaic cell. In the photovoltaic cell provided in this application embodiment, a protective layer is provided on the surface of the passivation layer away from the cutting surface. The material of the protective layer includes nitrides composed of one of the elements in Group III and nitrogen, such as boron nitride, aluminum nitride, and gallium nitride. These are all atomic crystals, so boron nitride, aluminum nitride, and gallium nitride have high stability and can protect the inner passivation layer, avoiding the problem of the passivation layer failing due to long-term contact with air and moisture, thereby improving the stability of the photovoltaic cell. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A top view of a whole battery cell divided into two segments after being cut, as provided in an embodiment of this application;

[0019] Figures 2 to 7 A cross-sectional structural schematic diagram of various photovoltaic cells provided in the embodiments of this application;

[0020] Figure 8 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of this application;

[0021] Figure 9 This is a flowchart corresponding to a method for manufacturing a photovoltaic cell provided in an embodiment of this application. Detailed Implementation

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

[0023] The photovoltaic cells, manufacturing methods, and photovoltaic modules provided in this application embodiment are at least beneficial for improving the photoelectric conversion efficiency of photovoltaic cells containing sectional cells.

[0024] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0025] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0027] In the description of the embodiments of this application, technical terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0028] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged 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 there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" 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 portion of the edge of the entire surface.

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

[0030] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise.

[0031] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0032] Figure 1 A top view of a whole battery cell divided into two segments after being cut, as provided in an embodiment of this application; Figure 2 This is a cross-sectional structural diagram of the first type of photovoltaic cell provided in the embodiments of this application. Figure 2 The Y-axis direction in the middle corresponds to Figure 1 The view from above.

[0033] Reference Figure 1 and Figure 2In some cases, the entire battery 100 has a first surface 110a and a second surface 110b arranged opposite each other. After the entire battery 100 is cut once, it is divided into two sub-batteries 110 arranged along the X-axis. The cut surface 110c formed on the sub-batteries 110 by the cutting process connects the first surface 110a and the second surface 110b. The cut surface 110c formed on the sub-batteries 110 by the cutting process will have a large number of dangling bonds, mechanical damage caused by the cutting process, or other surface defects. Moreover, due to the various surface defects on the cut surface 110c, impurities are also easily introduced. These defects and impurities can easily act as recombination centers for electron-hole pairs, shortening the carrier lifetime and leading to a decrease in the photoelectric conversion efficiency of the sub-batteries 110. It should be noted that the cutting process includes, but is not limited to, laser cutting, and laser cutting can also leave laser damage on the cut surface 110c.

[0034] refer to Figure 1 In some embodiments, the entire 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 Cell), a HIT / HJT cell (Heterojunction Technology), or a BC cell (Back Contact Cell). Correspondingly, the segmented cell 110 can be any one of the above-mentioned cell types.

[0035] refer to Figure 1 In some embodiments, the entire cell 100 can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-element compound solar cell. Specifically, the multi-element compound solar cell can be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell. Correspondingly, the segmented cell 110 can be any of the above-mentioned types of cells.

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

[0037] In the photovoltaic cell provided in this application embodiment, the cut surface 110c of the segmented cell 110 has a passivation layer 111. The passivation layer 111 contains a metal oxide material, and the metal element in the metal oxide material includes at least one of Al, Ti, Zn, Zr, Hf, Mo, W, or Ni. The metal element in the passivation layer 111 gives the passivation layer 111 itself a high density of fixed charge to generate a large electric field, thereby performing good field-effect passivation on the cut surface 110c. This results in a large band bending between the passivation layer 111 and the cut surface 110c, hindering the migration of minority carriers to the cut surface 110c and reducing the concentration of minority carriers at the cut surface 110c. This helps to reduce the recombination probability of majority carriers and minority carriers at the cut surface 110c and improve the efficiency of the photovoltaic cell containing the segmented cell 110. Furthermore, when only the passivation layer 111 is located on the cut surface 110c of the segmented cell 110, the metal oxide in the passivation layer 111, if in long-term contact with air, easily absorbs moisture from the air and adsorbs airborne particles, which may lead to the failure of the passivation layer 111 and cause a risk of reduced reliability of the photovoltaic cell. In the photovoltaic cell provided in this application embodiment, 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 one of the elements in Group III and nitrogen, such as boron nitride, aluminum nitride, and gallium nitride, which 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 the passivation layer 111 failing due to long-term contact with air and moisture, and improving the stability of the photovoltaic cell.

[0038] exist Figure 1 In this example, taking one cutting process as an example, the entire battery 100 is divided into two sub-batteries 110, and each sub-battery 110 has a cutting surface 110c. The accompanying drawings provided in this embodiment do not constitute a limitation on the number of cutting processes or the cutting method.

[0039] In a specific example, the cutting process can be performed twice. For instance, the entire cell can be cross-cut to divide it into four segments, each with two intersecting cut surfaces. Alternatively, the two cutting lines can be parallel to divide the cell into three segments, with the middle segment having two cut surfaces and the two segments on either side of it each having one cut surface. It's understood that regardless of whether a segment has one or more cut surfaces, a passivation layer and a protective layer can be applied to each cut surface to passivate the surface. Simultaneously, the protective layer protects the passivation layer, improving both the efficiency and stability of the photovoltaic cell.

[0040] In some embodiments, the metal element in the passivation layer 111 is Al, that is, the material of the passivation layer 111 is aluminum oxide. On one hand, the aluminum oxide material gives the passivation layer 111 a high density of fixed negative charges (e.g., Qf is approximately 10). 12 cm -2 ~10 13 cm -2 This process improves the passivation effect on the cut surface 110c, reduces the probability of carrier recombination at the cut surface 110c, and thus improves the photoelectric conversion efficiency of the segmented cell 110. On the other hand, the technology of forming a passivation layer 111 containing alumina material also ensures that the passivation layer 111 contains an appropriate amount of hydrogen ions, so that the passivation layer 111 has a good hydrogen passivation effect on the cut surface 110c. The appropriate amount of hydrogen ions in the passivation layer 111 can effectively saturate the dangling bonds on the cut surface 110c by migration, and can also suppress recombination with carriers, which helps to ensure that carriers effectively converge to the corresponding electrodes in the segmented cell 110, thereby further improving the photoelectric conversion efficiency of the segmented cell 110.

[0041] In other embodiments, the metal element in the passivation layer 111 is Mo, i.e., the material of the passivation layer 111 is molybdenum oxide. On the one hand, the molybdenum oxide material gives the passivation layer 111 a high work function, which is also beneficial for the passivation layer 111 to have a good field passivation effect on the cut surface 110c; on the other hand, in the technique of forming the passivation layer 111 containing molybdenum oxide material, the passivation layer 111 also contains an appropriate 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 illustrating the good passivation effect of the metal oxide material in the passivation layer 111 on the cut surface 110c. In practical applications, the metal element in the metal oxide material includes at least one of Al, Ti, Zn, Zr, or Hf, which can give the passivation layer 111 a high density of fixed negative charge to achieve a good field passivation effect on the cut surface 110c; the metal element in the metal oxide material includes at least one of Mo, W, or Ni, which can give the passivation layer 111 a high density of fixed positive charge or a high work function to achieve a good field passivation effect on the cut surface 110c.

[0043] Figure 3 This is a schematic cross-sectional view of a second type of photovoltaic cell provided in an embodiment of this application. Wherein, Figure 3 The Y-axis direction in the middle corresponds to Figure 1 The view from above.

[0044] refer to Figure 3 In some embodiments, an intermediate layer 131 is provided between the passivation layer 111 and the protective layer 121. 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 Group 3 element as the nitride in the protective layer 121. As a transition layer between the passivation layer 111 and the protective layer 121, the intermediate layer 131 can facilitate a better lattice fit at the contact interface between the passivation layer 111 and the protective layer 121, avoiding the problem of increased defects in the cut surface 110c due to lattice mismatch, thus maintaining a good passivation effect of the passivation layer 111.

[0045] In some cases, the protective layer 121 can be formed directly on the surface of the passivation layer 111, and the intermediate layer 131 can be formed by the diffusion of metal elements from the passivation layer 111 to the protective layer 121, and the diffusion of Group III elements from the protective layer 121 to 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, the ratio of the thickness of the passivation layer 111 to the thickness of the protective layer 121 along the direction perpendicular to the cut surface 110c is 0.7 to 2, for example, 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 sufficiently thick to provide adequate protection for the passivation layer 111; on the other hand, excessive thickness of the protective layer 121 does not necessarily increase the protective effect but instead leads to an increase in 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 good protective 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 cut 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 a single-layer structure as an example; in other embodiments, the passivation layer 111 can also be a multi-layer structure.

[0049] Figure 4 This is a schematic cross-sectional view of a third type of photovoltaic cell provided in an embodiment of this application. Wherein, Figure 4 The Y-axis direction in the middle corresponds to Figure 1 The view from above.

[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 cut surface 110c, and the second sub-passivation layer 151 is located on the side of the first sub-passivation layer 141 away from the cut 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 a metal oxide.

[0051] The first sub-passivation layer 141 contains silicon oxide material, which can chemically passivate the cut surface 110c. For example, 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 carrier recombination probability. The second sub-passivation layer 151 comprises a metal oxide material, wherein the metal element in the metal oxide material includes at least one of Al, Ti, Zn, Zr, Hf, Mo, W, or Ni. The metal element in the second sub-passivation layer 151 enables it to possess a high density of fixed charges. This high density of fixed charges generates a large electric field, effectively passivating the cut surface 110c through a field effect. This results in significant band bending between the second sub-passivation layer 151 and the cut surface 110c, hindering minority carrier migration to the cut surface 110c and reducing the minority carrier concentration at the cut surface 110c. This, in turn, helps to reduce the recombination probability of majority and minority carriers at the cut surface 110c. Thus, the first sub-passivation layer 141 and the second sub-passivation layer 151 work together to significantly improve the photoelectric conversion efficiency of the segmented cell 110, thereby increasing the photoelectric conversion efficiency of the photovoltaic cell.

[0052] Figure 5 This is a schematic cross-sectional view of the fourth type of photovoltaic cell provided in an embodiment of this application. Wherein, Figure 5 The Y-axis direction in the middle corresponds to Figure 1 The view from above.

[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. 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 serves as a transition layer to improve the lattice fit 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 sequential contact. This prevents voids and misalignments from appearing 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 sequential contact, thereby improving the uniformity of the passivation layer 111 itself and thus improving the interface passivation effect of the passivation layer 111 on the segmented battery 110. Furthermore, the third sub-passivation layer 161 helps to improve the connection strength between the first sub-passivation layer 141 and the second sub-passivation layer 151, thereby avoiding the mutual slippage or detachment of 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, which helps to improve the structural stability of the passivation layer 111.

[0054] The third sub-passivation layer 161 not only has the same silicon and oxygen elements as the first sub-passivation layer 141, but also has the same metal elements as the second sub-passivation layer 151. This allows the third sub-passivation layer 161 to serve as a transition layer between the first sub-passivation layer 141 and the second sub-passivation layer 151. Furthermore, by utilizing the oxygen atoms in the third sub-passivation layer 161 and based on the migration of these oxygen atoms toward the cut surface 110c, the dangling bonds on the cut surface 110c can be further saturated, thereby further reducing the defect state density of the cut surface 110c and thus further reducing the recombination centers of the cut surface 110c to lower the carrier recombination probability.

[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, while the metal content in the third sub-passivation layer 161 gradually increases. This is beneficial for improving the performance stability of the third sub-passivation layer 161 and avoiding performance mutations caused by abrupt changes in the element content of the third sub-passivation layer 161.

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

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

[0058] It is worth noting that the first sub-passivation layer 141 contains silicon oxide. A smaller thickness of the silicon oxide material ensures good chemical passivation of the cut surface 110c while simplifying the formation process. Furthermore, a smaller thickness of the first sub-passivation layer 141, especially when the third sub-passivation layer 161 contains oxygen, facilitates the migration of oxygen atoms from the third sub-passivation layer 161 to the cut surface 110c, further enhancing the chemical passivation effect. The third sub-passivation layer 161 serves as a transition layer between the first and second sub-passivation layers 141 and 151. The thickness of the third sub-passivation layer 161 should be appropriate, ideally facilitating the migration of oxygen atoms from the third sub-passivation layer 161 to the cut surface 110c. The second sub-passivation layer 151 contains a metal oxide material. A greater thickness of the metal oxide film results in better field-effect passivation of the cut 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 thickness of the second sub-passivation layer 151 and the first sub-passivation layer 141. This ensures that the first sub-passivation layer 141 has a good chemical passivation effect on the cut surface 110c, and also ensures that the second sub-passivation layer 151 has a good field effect passivation effect on the cut surface 110c. Furthermore, it facilitates the migration of oxygen atoms in the third sub-passivation layer 161 to the cut surface 110c.

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

[0060] Figure 6 This is a schematic cross-sectional view of the fifth type of photovoltaic cell provided in this application embodiment. Wherein, Figure 6 The Y-axis direction in the middle corresponds to Figure 1 The view from above.

[0061] refer to Figure 6In some embodiments, the angle between the cutting surface 110c and the plane containing the first surface 110a is an acute angle, and the angle between the cutting surface 110c and the plane containing the second surface 110b is an obtuse angle. That is, the cutting surface 110c is tilted relative to the plane perpendicular to the first surface 110a or the second surface 110b. The atomic arrangement density and covalent bond density on the tilted cutting surface 110c are smaller, so the connection between adjacent atoms on the cutting surface 110c is not strong. This is more conducive to the passivation layer 111 on the cutting surface 110c forming bonds with the dangling bonds on the cutting surface 110c. That is, it makes the passivation layer 111 more likely to saturate the dangling bonds on the cutting surface 110c. In addition, 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, thereby further reducing the recombination centers on the cutting surface 110c and reducing the carrier recombination probability. In other words, designing the cut surface 110c of the segmented cell 110 to be relatively inclined rather than vertical, and in conjunction with the passivation function of the passivation layer 111, is beneficial to further improve the passivation effect of the passivation layer 111 on the cut surface 110c, so as to further reduce the probability of carrier recombination on the cut surface 110c, improve the carrier lifetime, and thus further improve the photoelectric conversion efficiency of the photovoltaic cell containing the segmented cell.

[0062] In some embodiments, the acute angle can be 45° to 80°, for example, 45°, 46°, 47°, 48°, 49°, 50°, 60°, 65°, 70°, 76° or 80°. This can help make the cut surface 110c approach the fcc(111) crystal plane of the segmented battery 110. Compared with other crystal planes, the fcc(111) crystal plane has the lowest atomic arrangement density and the lowest covalent bond density, and the connection between adjacent atoms is not strong. Furthermore, the acute angle formed between the plane containing the cut surface 110c and the first surface 110a can be designed to be 45° to 50°. This is beneficial to minimize the atomic arrangement density on the cut surface 110c and maximize the ability of the passivation layer 111 to saturate the dangling bonds on the cut surface 110c. This further enhances the passivation effect of the passivation layer 111 on the cut surface 110c, thereby further reducing the probability of carrier recombination on the cut surface 110c, increasing the carrier lifetime, and thus further improving the photoelectric conversion efficiency of the photovoltaic cell containing the segmented cell.

[0063] The corresponding obtuse angle is 100° to 135°, for example, it can be 100°, 115°, 123°, 130° or 135°. It is understandable that the cut 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 view of the sixth type of photovoltaic cell provided in this application embodiment. Wherein, Figure 7 The Y-axis direction in the middle corresponds to Figure 1 The view from above.

[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 cell 110. In another example, the protective layer 121 may extend only to the first side 110a of the cell 110. In yet another example, the protective layer 121 may extend only to the second side 110b of the cell 110.

[0066] Since it is difficult for the encapsulation materials of photovoltaic modules formed from photovoltaic cells to achieve 100% isolation from the outside environment, moisture may enter the photovoltaic cells through the encapsulation materials or backsheets used for edge sealing in humid environments. In this case, the glass in the encapsulation material will generate sodium ions. Under the influence of an applied electric field, these sodium ions move towards the surface of the photovoltaic cell, causing PID (Potential Induced Degradation), which reduces the photoelectric conversion efficiency of the photovoltaic cell. The protective layer 121 extends to the first surface 110a of the segmented cell 110, and / or to the second surface 110b of the segmented cell 110, preventing moisture from entering the cut surface 110c and into the segmented cell 110, thus providing better anti-PID effect. Therefore, even if the encapsulation material of the photovoltaic module cannot achieve complete insulation, and moisture enters the environment where the photovoltaic cell is located through the encapsulation material used for edge sealing, the protective layer 121 can prevent sodium ions in the glass of the encapsulation material from moving towards the cut surface 110c, thereby preventing PID and maintaining a high photoelectric conversion efficiency of the photovoltaic cell.

[0067] In some embodiments, the protective layer 121 extends from the edge of the segmented cell 110 toward the center of the segmented cell 110 with a width of 0 to 2 mm, such as 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 if the protective layer 121 extends too far from the edge of the segmented cell 110 toward the center of the segmented cell 110, it may cause the first surface 110a or the second surface 110b of the segmented 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 segmented cell 110 toward the center of the segmented cell 110 needs to be within an appropriate range.

[0068] In the photovoltaic cell provided in this application embodiment, the cut surface 110c of the segmented cell 110 has a passivation layer 111. The passivation layer 111 contains a metal oxide material, and the metal element in the metal oxide material includes at least one of Al, Ti, Zn, Zr, Hf, Mo, W, or Ni. The metal element in the passivation layer 111 gives the passivation layer 111 itself a high density of fixed charge to generate a large electric field, thereby performing good field-effect passivation on the cut surface 110c. This results in a large band bending between the passivation layer 111 and the cut surface 110c, hindering the migration of minority carriers to the cut surface 110c and reducing the concentration of minority carriers at the cut surface 110c. This helps to reduce the recombination probability of majority carriers and minority carriers at the cut surface 110c and improve the efficiency of the photovoltaic cell containing the segmented cell 110. Furthermore, when only the passivation layer 111 is located on the cut surface 110c of the segmented cell 110, the metal oxide in the passivation layer 111, if in long-term contact with air, easily absorbs moisture from the air and adsorbs airborne particles, which may lead to the failure of the passivation layer 111 and cause a risk of reduced reliability of the photovoltaic cell. In the photovoltaic cell provided in this application embodiment, 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 nitrides composed of one element from Group III and nitrogen, such as boron nitride, aluminum nitride, and gallium nitride, which are all atomic crystals. Therefore, 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 moisture, and improving the stability of the photovoltaic cell.

[0069] Accordingly, another embodiment of this application also provides a photovoltaic module, including any of the photovoltaic cells described in the above embodiments. The photovoltaic module provided in another embodiment of this application will be described in detail below with reference to the accompanying drawings. For parts that are the same as or corresponding to the previous embodiment, please refer to the corresponding descriptions of the foregoing embodiments; detailed descriptions will not be repeated below.

[0070] Figure 8 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of this application.

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

[0072] refer to Figure 8Adjacent photovoltaic cells 201 can be connected by solder ribbons 202, and multiple photovoltaic cells 201 can be electrically connected in series and / or parallel. Based on the photovoltaic cells 201 in the above embodiment, the power loss of the photovoltaic module is improved by reducing the current of the segmented cells, thereby improving the photoelectric conversion efficiency of the photovoltaic module.

[0073] exist Figure 8 The diagram illustrates the positional relationship between photovoltaic cells 201, where the positive electrodes of the photovoltaic cells 201 are all arranged facing the same side, and solder ribbons 202 connect different sides of two adjacent photovoltaic cells 201 respectively. In some embodiments, the photovoltaic cells can also be arranged with electrodes of different polarities facing the same side, that is, the electrodes of multiple adjacent photovoltaic cells are arranged in the order of first polarity, second polarity, and first polarity, respectively, and then solder ribbons connect two adjacent photovoltaic cells on the same side.

[0074] In some embodiments, there is no spacing between photovoltaic cells, meaning that the photovoltaic cells overlap each other.

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

[0076] The cover plate 204 can be a glass cover plate, a plastic cover plate, or other cover plates with light transmission function.

[0077] In some embodiments, the surface of the cover plate 204 facing the adhesive film 203 can be an uneven surface, thereby increasing the utilization rate of incident light.

[0078] Accordingly, another embodiment of this application also provides a method for manufacturing a photovoltaic cell, used to form the photovoltaic cell in the above embodiment. For parts that are the same as or corresponding to the previous embodiment, please refer to the corresponding descriptions of the foregoing embodiments, which will not be repeated in detail below.

[0079] Figure 9 This is a flowchart corresponding to a method for manufacturing a photovoltaic cell provided in an embodiment of this application.

[0080] refer to Figure 9 The method for manufacturing photovoltaic cells provided in this application includes:

[0081] Step 301: Provide the complete battery cell.

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

[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-component compound solar cell. Specifically, the multi-component compound solar cell can 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: The entire battery cell is cut to form multiple segmented batteries, each segmented battery having a cut surface. The cutting process includes, but is not limited to, laser cutting.

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

[0086] The processes for forming a passivation layer include, but are not limited to, chemical vapor deposition, physical vapor deposition, or atomic layer deposition.

[0087] Step 304: Form a protective layer on the surface of the passivation layer away from the cutting surface. The material of the protective layer includes nitrides, which are composed of one element from Group III and nitrogen.

[0088] The processes for forming a protective layer include, but are not limited to, chemical vapor deposition, physical vapor deposition, or atomic layer deposition.

[0089] In some embodiments, the protective layer and the passivation layer can be formed in the same process step. The material types of the protective layer and the passivation layer can be adjusted by regulating the reactive gas source. Forming the protective layer and the passivation layer in the same process step can help improve the manufacturing efficiency of photovoltaic cells.

[0090] In the photovoltaic cell manufacturing method provided in this application embodiment, a passivation layer is formed on the cut surface of the segmented cell. The passivation layer comprises a metal oxide material, and the metal element in the metal oxide material includes at least one of Al, Ti, Zn, Zr, Hf, Mo, W, or Ni. The metal element in the passivation layer gives the passivation layer itself a high density of fixed charge, thereby generating a large electric field. This effectively passivates the cut surface through the field effect, resulting in a large band bending between the passivation layer and the cut surface. This hinders the migration of minority carriers to the cut surface, reduces the concentration of minority carriers at the cut surface, and thus helps to reduce the recombination probability of majority and minority carriers at the cut surface, improving the efficiency of the photovoltaic cell containing the segmented cells. Furthermore, when only the passivation layer is located on the cut surface of the segmented cell, if the metal oxide in the passivation layer is in long-term contact with air, it easily absorbs moisture and adsorbs airborne particles, which may lead to the failure of the passivation layer and reduce the reliability of the photovoltaic cell. In the photovoltaic cell manufacturing method provided in this application embodiment, 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 nitrides composed of one element from Group III and nitrogen, such as boron nitride, aluminum nitride, and gallium nitride, which are all atomic crystals. Therefore, boron nitride, aluminum nitride, and gallium nitride have high stability and can protect the inner passivation layer, avoiding the problem of the passivation layer failing due to long-term contact with air and moisture, thereby improving the stability of the photovoltaic cell.

[0091] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A photovoltaic cell, characterized in that, include: The segmented battery is obtained by cutting a whole battery, and the segmented battery has a cut surface formed by the cutting process; A passivation layer is located on the cut surface. The material of the passivation layer includes a metal oxide, and the metal element in the metal oxide includes at least one of Al, Ti, Zn, Zr, Hf, Mo, W, or Ni. A protective layer is located on the side of the passivation layer away from the cut surface. The material of the protective layer includes nitrides, which are composed of one element from Group III and nitrogen. The material of the protective layer includes boron nitride, aluminum nitride, and gallium nitride. An intermediate layer is provided between the passivation layer and the protective layer. 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 Group 3 element as the nitride in the protective layer.

2. The photovoltaic cell according to claim 1, characterized in that, Along the direction perpendicular to the cut surface, the ratio of the thickness of the passivation layer to the thickness of the protective layer is 0.7 to 2.

3. The photovoltaic cell according to claim 2, characterized in that, The thickness of the protective layer is 10 nm to 100 nm in the direction perpendicular to the cut surface.

4. 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 cut surface, and the second sub-passivation layer is located on the side of the first sub-passivation layer away from the cut 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.

5. The photovoltaic cell according to claim 4, characterized in that, The passivation layer further includes a third sub-passivation layer, which is located between the first sub-passivation layer and the second sub-passivation layer. The material of the third sub-passivation layer includes a metallic silicon oxide, and the metal element in the metallic silicon oxide is the same as the metal element in the second sub-passivation layer.

6. The photovoltaic cell according to claim 4, characterized in that, Along the direction perpendicular to the cut surface, the thickness of the protective layer is greater than or equal to the thickness of the second sub-passivation layer.

7. The photovoltaic cell according to claim 1, characterized in that, The segmented battery has a first side and a second side disposed opposite to each other, the cut surface connects the first side and the second side, the protective layer extends to the first side of the segmented battery, and / or the protective layer extends to the second side of the segmented battery.

8. A photovoltaic module, characterized in that, include: Battery string, the battery string comprising at least one photovoltaic cell as described in any one of claims 1 to 7; An adhesive film covering the surface of the battery string; A cover plate that covers the surface of the adhesive film away from the battery string.

9. A method for manufacturing a photovoltaic cell, characterized in that, include: Provide whole batteries; The whole battery is cut to form multiple segmented batteries, each segmented battery having a cut surface; A passivation layer is formed on the cut surface. The material of the passivation layer includes a metal oxide, and the metal element in the metal oxide includes at least one of Al, Ti, Zn, Zr, Hf, Mo, W, or Ni. A protective layer is formed on the surface of the passivation layer away from the cut surface. The material of the protective layer includes a nitride, which is composed of an element from Group III and nitrogen. The material of the protective layer includes boron nitride, aluminum nitride, and gallium nitride. An intermediate layer is provided between the passivation layer and the protective layer. The material of the intermediate layer includes the same metal element as the metal oxide in the passivation layer and the same Group III element as the nitride in the protective layer.

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