Solar cell and preparation method thereof

Abstract

The embodiment of the invention relates to the technical field of photovoltaics, and provides a solar cell and a preparation method thereof, so as to improve the photoelectric conversion efficiency of the solar cell and greatly reduce the mechanical damage of the cell, thereby greatly reducing the hidden crack possibility of a photovoltaic module comprising the cell, and further improving the product yield. The solar cell comprises a sub-front surface and a sub-back surface which are oppositely arranged along a second direction, the second direction is the thickness direction of the solar cell, the solar cell further comprises a cross section connecting the sub-front surface and the sub-back surface, and the cross section is a silicon surface with a hydrogen-oxygen bond; and the passivation layer is located on the fracture surface.

Description

Cross Reference to Related Applications

[0001] This application is a divisional application of the Chinese Patent Application No. 202411506607.7, filed on October 25, 2024, with the title of “Solar Cell and Preparation Method Thereof”. TECHNICAL FIELD

[0002] Embodiments of the present disclosure relate to the field of photovoltaic technology, in particular to a solar cell and a preparation method thereof. BACKGROUND

[0003] In order to improve the energy density of photovoltaic modules, module half-piece technology, overlap welding technology, and tile technology are constantly developing. Such technologies need to cut whole solar cell pieces into halves, thirds, or even smaller sizes to increase the effective power generation area, reduce power loss, and improve module power.

[0004] At present, laser cutting process is used to realize the segmentation of whole solar cell pieces. The laser cutting process includes: first, using laser ablation process to groove, and then using mechanical method to make the whole solar cell piece break at the grooving position. However, this process is prone to mechanical damage, and the photovoltaic module formed by the cut cell piece is prone to hidden cracks, thereby reducing product yield; at the same time, there are hanging keys on the cutting section, which form electron-hole recombination centers, thereby reducing the photoelectric conversion efficiency of the cut cell piece, and ultimately reducing the power of the photovoltaic module. SUMMARY

[0005] Embodiments of the present disclosure provide a solar cell and a preparation method thereof to improve the photoelectric conversion efficiency of the solar cell, while greatly reducing the mechanical damage of the cell, thereby greatly reducing the possibility of hidden cracks in the photovoltaic module including the cell, and further improving the product yield.

[0006] According to some embodiments of the present disclosure, the present disclosure provides a solar cell, which includes: a sub-front surface and a sub-back surface oppositely arranged along a second direction, the second direction being a thickness direction of the solar cell, the solar cell further including a section surface connecting the sub-back surface and the sub-front surface, the section surface being a silicon surface with hydrogen-oxygen bonds; and a passivation layer located on the section surface.

[0007] According to some embodiments of the present disclosure, an included angle formed by the section surface and the sub-back surface or the sub-front surface is an acute angle.

[0008] According to some embodiments of the present disclosure, the acute angle ranges from 45° to 80°.

[0009] According to some embodiments of this disclosure, along a third direction, the passivation layer includes at least a first passivation layer and a second passivation layer stacked together. The first passivation layer contains a silicon oxide material, and the second passivation layer contains a metal oxide material. The metal element in the metal oxide material includes at least one of Al, Ti, Zn, Zr, Hf, Mo, W, or Ni. The third direction is perpendicular to the cross-section.

[0010] According to some embodiments of this disclosure, the passivation layer further includes an intermediate passivation layer located between the first passivation layer and the second passivation layer, and both the intermediate passivation layer and the first passivation layer contain silicon, and the intermediate passivation layer and the second passivation layer contain the same metal element.

[0011] According to some embodiments of this disclosure, the material of the intermediate passivation layer comprises an oxide having the silicon element and the metal element.

[0012] According to some embodiments of this disclosure, along the direction from the first passivation layer to the second passivation layer, the content of silicon in the intermediate passivation layer shows a decreasing trend, while the content of metal in the intermediate passivation layer shows an increasing trend.

[0013] According to some embodiments of this disclosure, the intermediate passivation layer further contains oxygen, and along the direction from the first passivation layer to the second passivation layer, the content of oxygen in the intermediate passivation layer first increases and then decreases.

[0014] According to some embodiments of this disclosure, along the direction from the first passivation layer to the second passivation layer, the thickness of the first passivation layer is less than the thickness of the intermediate passivation layer, and the thickness of the intermediate passivation layer is less than the thickness of the second passivation layer.

[0015] According to some embodiments of this disclosure, the solar cell further includes: a side surface connecting the sub-back side and the sub-front side; a substrate having a first surface and a second surface opposite to each other along the second direction; a side passivation film located on the side surface; a first passivation film located on the first surface; and a second passivation film located on the second surface; wherein the material of the side passivation film is the same as the material of the first passivation film and / or the second passivation film.

[0016] According to some embodiments of this disclosure, one aspect of this disclosure provides a method for fabricating a solar cell, comprising: providing a whole solar cell; wherein the whole solar cell includes a region to be divided; forming positioning grooves at both ends of the region to be divided using a first laser device; heating the region to be divided using a second laser device starting from the positioning grooves until the other positioning groove ends; spraying a cooling liquid onto the heated region to be divided using a spraying device, causing the whole solar cell to split along a first direction in the region to be divided to form at least two segmented cells; wherein the cooling liquid includes an oxidizing substance, the segmented cells include a sub-front and a sub-back arranged opposite each other along a second direction, and a cross-section formed by splitting the whole solar cell along the first direction, the second direction being the thickness direction of the segmented cells, the whole solar cell having a front and a back arranged opposite each other along the second direction, the sub-front of the at least two segmented cells formed based on the same whole solar cell being a portion of the front, and the sub-back of the at least two segmented cells formed based on the same whole solar cell being a portion of the back; the cross-section being a silicon surface after surface hydroxylation; and forming a passivation layer on the cross-section.

[0017] According to some embodiments of this disclosure, the oxidizing substance includes H2O2 or O3.

[0018] According to some embodiments of this disclosure, the concentration of the oxidizing substance in the cooling liquid ranges from 0.5% to 50%.

[0019] According to some embodiments of this disclosure, the spraying device includes a nozzle; In the process of spraying cooling liquid onto the heated area to be segmented using a spraying device, the distance between the projection of the nozzle on the area to be segmented and the laser spot formed by the second laser device on the area to be segmented along the laser scanning direction is in the range of 1-10 mm.

[0020] According to some embodiments of this disclosure, the laser temperature of the second laser device is in the range of 150°C to 250°C.

[0021] This disclosure provides a solar cell and its fabrication method. On one hand, because the fabrication method is based on the principle of thermal stress cell separation, it achieves the segmentation of the entire solar cell without the need for ablation of the area to be cut, effectively reducing mechanical damage to the segmented cells. This significantly reduces the possibility of microcracks in photovoltaic modules including the segmented cells, thereby improving product yield. On the other hand, the fabrication method uses a coolant containing oxidizing substances to cool the heated area to be segmented, ensuring that the cross-section of the segmented cells formed after the entire solar cell is split along a first direction is a silicon surface with surface hydroxylation. This neutralizes dangling bonds and provides protection for the exposed silicon at the cross-section. Furthermore, when a passivation layer is subsequently formed on the cross-section, the surface hydroxylation... The resulting silicon surface and passivation layer will be more structurally continuous, leading to better passivation improvement. Furthermore, this fabrication method allows the entire solar cell to be split along a first direction in the area to be divided. This first direction intersects with a second direction, which is the thickness direction of the segmented cell. In other words, the entire solar cell is obliquely cut to form segmented cells. The oblique cross-section formed on the segmented cell has a lower atomic density and a lower covalent bond density. The weaker connections between adjacent atoms on the cross-section are more conducive to the formation of bonds between the passivation layer and the dangling bonds on the cross-section, thus further improving the passivation effect of the passivation layer on the cross-section. This further reduces the probability of carrier recombination on the cross-section, increases carrier lifetime, and ultimately improves the photoelectric conversion efficiency of the segmented cell. Attached Figure Description

[0022] 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 disclosure or 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 disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A schematic flowchart illustrating a method for fabricating a solar cell according to an embodiment of this disclosure; Figure 2 A cross-sectional view of a single monolithic solar cell divided into at least two sub-cells, as provided in an embodiment of this disclosure. Figure 3 A top view schematic diagram of a single monolithic solar cell divided into two segmented cells, as provided in an embodiment of this disclosure; Figure 4A top view schematic diagram of a single monolithic solar cell divided into four sub-cells according to an embodiment of this disclosure; Figure 5 A top view schematic diagram of a single monolithic solar cell divided into 9 sub-cells according to an embodiment of this disclosure; Figure 6 A schematic diagram of the cross-section provided in an embodiment of this disclosure; Figure 7 In order to be in Figure 6 A schematic diagram of the structure in which a passivation layer is formed on the cross-section shown; Figure 8 A top view of a whole solar cell with positioning grooves provided in an embodiment of this disclosure; Figure 9 This is a schematic diagram of the movement trajectory of the second laser device provided in an embodiment of this disclosure; Figure 10 This is a partial cross-sectional structural diagram of a solar cell provided in an embodiment of the present disclosure; Figure 11 This is a schematic diagram showing the positional relationship between the nozzle and the second laser device provided in an embodiment of this disclosure; Figures 12-14 Schematic diagrams of three partial cross-sectional structures of a solar cell provided in embodiments of this disclosure; Figure 15 for Figure 14 The graph shows the percentage of elemental content in the segmented battery and passivation layer. Figure 16 and Figure 17 Two other partial cross-sectional structural diagrams of the solar cell provided in the embodiments of this disclosure; Figure 18 This is a partial three-dimensional structural diagram of a photovoltaic module provided in an embodiment of the present disclosure; Figure 19 for Figure 18 A schematic diagram of a cross-sectional structure along the cross-sectional direction NN1. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this disclosure clearer, the technical solutions of this disclosure will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0025] In the description of the embodiments disclosed herein, "at least one" means one or more, "multiple" means two or more, and "multiple pieces" refers to two or more pieces, unless otherwise explicitly specified.

[0026] In the description of the embodiments disclosed herein, 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 indicating the number, specific order, or primary and secondary relationship of the indicated technical features.

[0027] 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 disclosure. 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.

[0028] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," 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.

[0029] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0030] 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 (such as a layer, film, region, or substrate) on 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.

[0031] 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. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly" on the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Moreover, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0032] This disclosure provides a method for fabricating a solar cell, referring to... Figure 1 As shown, it includes: S1. Provide a complete solar cell; wherein the complete solar cell includes the area to be divided.

[0033] The type of this monolithic solar cell is not limited. For example, it may include, but is not limited to, one or any combination of PERC (Passivated Emitter Rear Cell), IBC (Interdigitated Back Contact), TOPCon (Tunnel Oxide Passivated Contact), HIT / HJT (Heterojunction Technology), thin-film solar cells, or tandem solar cells. Thin-film solar cells include, but are not limited to, perovskite, copper indium selenide, gallium arsenide, or cadmium sulfide solar cells. Tandem solar cells include, but are not limited to, perovskite cells stacked with crystalline silicon cells, perovskite cells stacked with perovskite cells, or perovskite cells stacked with thin-film cells. The fabrication method of this monolithic solar cell can be obtained from relevant technologies based on different cell types, and will not be elaborated here.

[0034] refer to Figure 3 As shown, the entire solar cell 100 can be divided into two sub-cells 110; or, refer to Figure 3 As shown, the entire solar cell 100 can be divided into four sub-cells 110; or, refer to Figure 5 As shown, the entire solar cell 100 can be divided into nine sub-cells 110; of course, the entire solar cell can also be divided into other numbers of sub-cells, which is not limited here. The location and number of areas to be divided are determined based on the number of sub-cells into which the entire solar cell is divided.

[0035] S2. A first laser device is used to form positioning grooves at both ends of the area to be segmented.

[0036] The specific structure of the first laser device is not limited. For example, the first laser device may include a first laser for emitting laser light with a wavelength range of [200nm, 2000nm]. For example, the laser wavelength may be 248nm, 355nm, 375nm, 405nm, 450nm, 457nm, 532nm, 808nm, 980nm, 1064nm, 1310nm, or 1550nm, etc. Depending on the emitted laser wavelength, the first laser may be an infrared laser, a visible laser, or an ultraviolet laser, etc. The power range of the first laser can be [20W, 500W]. For example, the power of the first laser can be 20W, 40W, 60W, 80W, 100W, 150W, 180W, 200W, 250W, 280W, 300W, 350W, 380W, 400W, 450W, 480W, or 500W, etc.

[0037] The positioning groove only needs to be set at both ends of the area to be divided, eliminating the need to form a continuous cutting groove connecting both ends of the area to be divided as in conventional laser cutting processes. Therefore, the positioning groove formed in this embodiment is much smaller in size compared to the cutting groove formed by conventional laser cutting processes. The specific dimensions of the positioning groove (e.g., groove depth, groove width, and groove length) can be selected according to actual requirements and are not limited here.

[0038] S3. Use a second laser device to heat the area to be divided, starting from the positioning slot, until the other positioning slot ends.

[0039] The specific structure of the second laser device is not limited. For example, the second laser device may include a second laser for emitting laser light with a wavelength range of [200nm, 2000nm]. For example, the laser wavelength may be 248nm, 355nm, 375nm, 405nm, 450nm, 457nm, 532nm, 808nm, 980nm, 1064nm, 1310nm, or 1550nm, etc. Depending on the emitted laser wavelength, the second laser may be an infrared laser, a visible laser, or an ultraviolet laser, etc. The power range of the second laser can be [20W, 500W]. For example, the power of the second laser can be 20W, 40W, 60W, 80W, 100W, 150W, 180W, 200W, 250W, 280W, 300W, 350W, 380W, 400W, 450W, 480W, or 500W, etc.

[0040] In this embodiment, the second laser and the first laser can be the same type of laser, for example, both can be infrared lasers, visible light lasers, or ultraviolet lasers. Alternatively, the second laser and the first laser can be different types of lasers, for example, the first laser is an infrared laser and the second laser is a visible light laser. Furthermore, the power of the second laser and the first laser can be the same or different; this is not limited here.

[0041] S4. A spraying device is used to spray cooling liquid onto the heated area to be segmented, so that... Figure 2 The entire solar cell 100 shown is split along a first direction X in the area to be divided to form at least two segmented cells 110; wherein the cooling liquid includes an oxidizing substance, the first direction X intersects with a second direction Y, the second direction Y is the thickness direction of the segmented cell, the segmented cell 110 includes a sub-front face 110a and a sub-back face 110b arranged opposite each other along the second direction Y, and a cross-section 110c formed by splitting the entire solar cell 100 along the first direction X, the planes containing the cross-section 110c and the sub-back face 110b form two complementary angles β and γ, one of which is an acute angle ( Figure 2 As shown in γ), reference Figure 2 As shown, the entire solar cell 100 has a front side 100a and a back side 100b arranged opposite each other along the second direction Y. The sub-front side 110a of at least two segmented cells 110 formed based on the same entire solar cell is a portion of the front side 100a, and the sub-back side 110b of at least two segmented cells formed based on the same entire solar cell is a portion of the back side 100b; the cross-section is... Figure 6 The silicon surface shown is hydroxylated.

[0042] The specific structure of the above-mentioned spraying device is not limited, as long as it can achieve the corresponding function.

[0043] In this embodiment, steps S2-S4 are based on the thermal stress cell separation principle to achieve non-destructive segmentation of the entire solar cell. The thermal stress cell separation principle is as follows: First, the material is rapidly heated locally using a laser, followed by a matching cooling technology to cool the heated area, thereby generating a non-uniform temperature field. This temperature field creates a temperature gradient on the material surface, inducing thermal stress. The laser spot is under compressive stress, while the areas before and after the laser spot are under tensile stress. Since the compressive stiffness of brittle materials is much greater than their tensile strength, when the tensile stress reaches the material's fracture strength, the material will fracture. The fracture will begin at the groove at the edge of the cell and steadily expand along the moving trajectory of the laser and subsequent cooling.

[0044] This explanation uses the example of a single solar cell being divided into two segments. (Reference) Figure 8As shown, the entire solar cell 100 can be divided into two sub-cells 110, with positioning grooves 1 formed at both ends of the area to be divided A, as shown in the reference diagram. Figure 9 As shown, when the laser generated by the second laser device heats the area A to be divided starting from the positioning groove, its movement trajectory is shown as the thick black line 2. The spraying device follows the second laser device and sprays cooling liquid onto the heated area to be divided. Based on the above-mentioned battery separation principle, refer to... Figure 2 As shown, the entire solar cell is split along the first direction X in the region to be divided to form two segmented cells 110. Of course, if the entire solar cell is divided into more than two segmented cells, the above steps S2-S4 need to be performed on different regions to be divided in the entire solar cell to obtain more than two segmented cells.

[0045] In this embodiment of the present disclosure, in step S4, a coolant containing an oxidizing agent is used to cool the heated area to be divided. Thus, the cross-section of the segmented cells formed after the entire solar cell is split along the first direction is as follows: Figure 6 The silicon surface shown is hydroxylated, reference Figure 6 As shown, hydrogen-oxygen bonds are formed on the silicon surface of the segmented cell, which can neutralize dangling bonds and provide protection for the exposed silicon at the cross-section; additionally, reference Figure 7 As shown, when the passivation layer 101 is subsequently formed on the cross-section, since the passivation layer is mostly made of oxide materials, the silicon surface after surface hydroxylation (i.e., cross-section 110c) and the passivation layer 101 will be more continuous in structure, and the passivation improvement effect will be better.

[0046] It should be noted that, in this embodiment of the present disclosure, the size of the laser spot emitted by the second laser device can be controlled to cause the entire solar cell to split along a first direction in the area to be divided. The first direction intersects with a second direction, where the second direction is the thickness direction of the split cell, i.e., reference direction. Figure 2 As shown, the entire solar cell 100 is obliquely cut to form a segmented cell 110. For the sub-front side 110a and sub-back side 110b on the segmented cell 110, the cross-section on the segmented cell 110 can be regarded as an oblique surface.

[0047] Compared to related technologies that divide the entire solar cell along its thickness to form segmented cells, reference Figure 10As shown in the present embodiment, the atomic arrangement density and covalent bond density are smaller on the inclined cross-section 110c formed on the segmented battery 110. The connection between adjacent atoms on the cross-section 110c is not strong, which is more conducive to the passivation layer 101 on the cross-section 110c forming bonds with the dangling bonds on the cross-section 110c. This makes it easier for the passivation layer 101 to saturate the dangling bonds on the cross-section 110c. In addition, the passivation layer 101 can also passivate other surface defects on the cross-section 110c, which is conducive to further improving the ability of the passivation layer 101 to reduce the defect state density of the cross-section 110c, so as to further reduce the recombination center of the cross-section 110c and reduce the carrier recombination probability. In other words, designing the cross-section 110c of the segmented cell 110 to be inclined rather than perpendicular to its sub-back surface 110b, and cooperating with the passivation function of the passivation layer 101, is beneficial to further improve the passivation effect of the passivation layer 101 on the cross-section 110c, so as to further reduce the probability of carrier recombination on the cross-section 110c, improve the carrier lifetime, and thus further improve the photoelectric conversion efficiency of the segmented cell.

[0048] S5, Reference Figure 10 As shown, a passivation layer 101 is formed on the cross section 110c.

[0049] In this embodiment of the disclosure, the passivation layer can be prepared using processes such as CVD (Chemical Vapor Deposition), PECVD (Plasma Enhanced Chemical Vapor Deposition), ALD (Atomic Layer Deposition), or PEALD (Plasma Enhanced Atomic Layer Deposition).

[0050] In this embodiment, the number of passivation layers, their thickness, and the material are not limited. For example, along a third direction, the passivation layer includes at least a first passivation layer and a second passivation layer stacked together. The first passivation layer contains silicon oxide, and the second passivation layer contains a metal oxide material. The metal element in the metal oxide material includes at least one of Al (aluminum), Ti (titanium), Zn (zinc), Zr (zirconium), Hf (hafnium), Mo (molybdenum), W (tungsten), or Ni (nickel), with the third direction perpendicular to the cross-section. Alternatively, the passivation layer may also include an intermediate passivation layer located between the first and second passivation layers. Both the intermediate and first passivation layers contain silicon, and both contain the same metal element. The intermediate passivation layer is made of an oxide containing silicon and a metal element. It should be noted that detailed structural descriptions of the passivation layer can be found in the subsequent descriptions of the solar cell embodiments, and will not be repeated here.

[0051] In this embodiment, the segmented solar cell is formed through steps S1-S5. On the one hand, since this preparation method is based on the principle of thermal stress cell separation, it achieves the segmentation of the entire solar cell without the need for ablation of the area to be cut, effectively reducing the mechanical damage of the segmented solar cell and thus significantly reducing the possibility of microcracks in the photovoltaic module including the segmented solar cell, thereby improving the product yield. On the other hand, the preparation method uses a coolant containing oxidizing substances to cool the heated area to be segmented, so that the cross-section of the segmented solar cell formed after the entire solar cell is cracked along the first direction is a silicon surface with surface hydroxylation. This can neutralize dangling bonds and provide protection for the exposed silicon at the cross-section. Moreover, when a passivation layer is subsequently formed on the cross-section, the surface hydroxylation... The resulting silicon surface and passivation layer will be more structurally continuous, leading to better passivation improvement. Furthermore, this fabrication method allows the entire solar cell to be split along a first direction in the area to be divided. This first direction intersects with a second direction, which is the thickness direction of the segmented cell. In other words, the entire solar cell is obliquely cut to form segmented cells. The oblique cross-section formed on the segmented cell has a lower atomic density and a lower covalent bond density. The weaker connections between adjacent atoms on the cross-section are more conducive to the formation of bonds between the passivation layer and the dangling bonds on the cross-section, thus further improving the passivation effect of the passivation layer on the cross-section. This further reduces the probability of carrier recombination on the cross-section, increases carrier lifetime, and ultimately improves the photoelectric conversion efficiency of the segmented cell.

[0052] In one or more embodiments, to enhance oxidizing properties, the oxidizing agent includes H2O2 or O3. The cooling liquid can be deionized water containing H2O2 or O3, or other liquids containing H2O2 or O3.

[0053] In one or more embodiments, the concentration of the oxidizing agent in the cooling liquid ranges from 0.5% to 50%. For example, the concentration of the oxidizing agent (e.g., H2O2 or O3) may be 0.5%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 27.5%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 43%, 45%, 48%, 49%, or 50%.

[0054] In one or more embodiments, the spraying device includes a nozzle; in step S3, the spraying device is used to spray cooling liquid into the heated area to be segmented, as referenced. Figure 11 As shown, the distance d between the projection of nozzle 3 onto the region A to be segmented and the laser spot formed by the second laser device 4 on the region A along the laser scanning direction M ranges from 1 to 10 mm. This distance can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. If this distance is too large, the heated region A to be segmented cannot be cooled quickly, thus affecting the generation of thermal stress; if this distance is too small, it will affect the heating effect of the region A to be segmented. Therefore, it is necessary to select an appropriate distance to balance both requirements.

[0055] In one or more embodiments, the laser temperature of the second laser device ranges from 150°C to 250°C. For example, the laser temperature of the second laser device is 150°C, 170°C, 190°C, 210°C, 230°C, or 250°C. Compared to the laser spot temperature of 400°C-500°C in conventional laser cutting processes, the preparation method provided in this disclosure has a lower processing temperature and lower manufacturing cost.

[0056] This disclosure also provides a solar cell, see embodiments thereof. Figure 2 , Figure 6 and Figure 10 The solar cell includes a front side 110a and a back side 110b disposed opposite to each other along a second direction Y, where the second direction Y is the thickness direction of the solar cell. The solar cell also includes a cross section 110c connecting the back side 110b and the front side 110a, where the cross section 110c is a silicon surface with hydrogen-oxygen bonds. The solar cell also includes a passivation layer 101 located on the cross section 110c.

[0057] Among them, the solar cell can be a segmented cell; the silicon surface with hydrogen-oxygen bonds can be a hydroxylated silicon surface.

[0058] This disclosure also provides a solar cell, with reference to... Figure 2 and Figure 10Solar cells include: segmented solar cells. Cell 110, at least two segmented cells 110 are formed by dividing the same whole solar cell 100 along a first direction X. The whole solar cell 100 has a front face 100a and a back face 100b arranged opposite each other along a second direction Y. The segmented cells 110 have a sub-front face 110a and a sub-back face 110b arranged opposite each other along the second direction Y. The sub-front face 110a of the at least two segmented cells 110 formed based on the same whole solar cell 100 is a part of the front face 100a, and the sub-back face 110b of the at least two segmented cells 110 formed based on the same whole solar cell 100 is a part of the back face 100b. The second direction Y is the thickness direction of the segmented cells 110, and the first direction X intersects the second direction Y. The segmented cells 110 have a cross-section 110c formed by the division process. The planes containing the cross-section 110c and the sub-back face 110b form two complementary angles, one of which is an acute angle. Figure 6 The silicon surface shown is hydroxylated; passivation layer 101 is located at least on cross section 110c.

[0059] It should be noted that the solar cell can be formed by any of the aforementioned solar cell preparation methods, or it can be formed by other preparation methods, which are not limited here.

[0060] In the solar cells provided in this disclosure, the cross-section of the segmented cells is as follows: Figure 6 The silicon surface shown is hydroxylated, reference Figure 6 As shown, hydrogen-oxygen bonds are formed on the silicon surface of the segmented cell, which can neutralize dangling bonds and provide protection for the exposed silicon at the cross-section; additionally, reference Figure 7 As shown, when the passivation layer 101 is subsequently formed on the cross section 110c, since the passivation layer 101 is mostly made of oxide materials, the silicon surface after surface hydroxylation and the passivation layer 101 will be more continuous in structure, and the passivation improvement effect will be better.

[0061] In the solar cell provided in the embodiments of this disclosure, reference is made to Figure 2 As shown, at least two segmented cells 110 are formed by dividing the same whole solar cell 100 along the first direction X. The first direction intersects with the second direction, which is the thickness direction of the segmented cell. That is, the whole solar cell 100 is obliquely cut to form the segmented cells 110. For the sub-front side 110a and sub-back side 110b on the segmented cell 110, the cross-section on the segmented cell 110 can be regarded as an oblique surface.

[0062] Compared to related technologies that divide the entire solar cell along its thickness to form segmented cells, reference Figure 10 As shown in the present embodiment, the atomic arrangement density and covalent bond density are smaller on the inclined cross-section 110c formed on the segmented battery 110. The connection between adjacent atoms on the cross-section 110c is not strong, which is more conducive to the passivation layer 101 on the cross-section 110c forming bonds with the dangling bonds on the cross-section 110c. This makes it easier for the passivation layer 101 to saturate the dangling bonds on the cross-section 110c. In addition, the passivation layer 101 can also passivate other surface defects on the cross-section 110c, which is conducive to further improving the ability of the passivation layer 101 to reduce the defect state density of the cross-section 110c, so as to further reduce the recombination center of the cross-section 110c and reduce the carrier recombination probability. In other words, designing the cross-section 110c of the segmented cell 110 to be inclined rather than perpendicular to its sub-back surface 110b, and cooperating with the passivation function of the passivation layer 101, is beneficial to further improve the passivation effect of the passivation layer 101 on the cross-section 110c, so as to further reduce the probability of carrier recombination on the cross-section 110c, improve the carrier lifetime, and thus further improve the photoelectric conversion efficiency of the segmented cell.

[0063] In this embodiment, on the one hand, the cross-section of the segmented cell is a silicon surface after surface hydroxylation. This can neutralize dangling bonds and protect the exposed silicon at the cross-section. Moreover, when a passivation layer is subsequently formed on the cross-section, the surface-hydroxylated silicon surface and the passivation layer will be more structurally continuous, resulting in better passivation improvement. On the other hand, at least two segmented cells are formed by dividing the same whole solar cell along a first direction. The first direction intersects with a second direction, which is the thickness direction of the segmented cell. That is, the whole solar cell is obliquely cut to form segmented cells. The atomic arrangement density and covalent bond density on the oblique cross-section formed on the segmented cell are smaller. The connection between adjacent atoms on the cross-section is not strong, which is more conducive to the formation of bonds between the passivation layer on the cross-section and the dangling bonds on the cross-section. This is conducive to further improving the passivation effect of the passivation layer on the cross-section, thereby further reducing the probability of carrier recombination on the cross-section, increasing the carrier lifetime, and thus further improving the photoelectric conversion efficiency of the segmented cell.

[0064] In some cases, refer to Figure 3 As shown, the corners where the four sides of the whole solar cell 100 are connected in sequence are rounded corners 100c. Based on this, the corners where the sides 110d of the cell 110 that have not been divided are connected in sequence are also rounded corners 100c. However, the corners of the cross-section 110c that is connected to the side 110d in the cell 110 do not have rounded corners.

[0065] In some cases, combined Figure 2 and Figure 3As shown, in two segmented cells 110 belonging to a single solar cell 100, the angle between the cross-section 110c of one segmented cell 110 and its sub-back surface 110b is a first angle β, and the angle between the cross-section 110c of the other segmented cell 110 and its sub-back surface 110b is a second angle γ. The first angle β and the second angle γ are complementary. It should be noted that... Figure 2 The example uses the first included angle β as an obtuse angle and the second included angle γ as an acute angle.

[0066] In other examples, refer to Figure 4 As shown, a single segmented cell 110 is 1 / 4 of a whole solar cell 100.

[0067] In some cases, refer to Figure 4 As shown, the segmentation path in the entire solar cell 100 is in the shape of a cross, so each segment cell 110 has a corner with a rounded corner 100c. Moreover, among the four segment cells 110 belonging to the same entire solar cell 100, each segment cell 110 has two cross sections 110c.

[0068] In one example, refer to Figure 4 As shown, in the two cross-sections 110c of the same segmented battery 110, the angle between one cross-section 110c and the sub-back face 110b of the segmented battery 110 is a third angle (not shown in the figure), and the angle between the other cross-section 110c and the segmented battery 110 is a fourth angle (not shown in the figure). Both the third and fourth angles are acute angles. In another example, refer to... Figure 4 As shown, in the two cross-sections 110c of the same cell 110, the angle between one cross-section 110c and the sub-back face 110b of the cell 110 is a third angle (not shown in the figure), and the angle between the other cross-section 110c and the cell 110 is a fourth angle (not shown in the figure). Both the third and fourth angles are obtuse angles. In another example, refer to... Figure 4 As shown, in the two cross-sections 110c of the same segmented battery 110, the angle between one cross-section 110c and the sub-back surface 110b of the segmented battery 110 is the third angle (not shown in the figure), and the angle between the other cross-section 110c and the segmented battery 110 is the fourth angle (not shown in the figure). One of the third angle and the fourth angle is an acute angle, and the other is an obtuse angle.

[0069] It should be noted that the first direction X intersecting the second direction Y has multiple possibilities. Based on the different choices of the first direction X, the two sections 110c of the same segmented battery 110 can present different tilt states. In practical applications, it can be flexibly designed according to requirements.

[0070] In other cases, the entire solar cell can also be divided into four segments along a fixed direction, in which case only two segments each have two rounded corners. Among the four segments belonging to the same solar cell, the two segments with rounded corners each have only one cross-section, while the remaining two segments each have two opposite cross-sections along the fixed direction.

[0071] It should be noted that, depending on the different ways of dividing the whole solar cell 100, the number of cross sections 110c and the tilt state of each cross section 110c may be different among the at least two sub-cells 110 belonging to a whole solar cell 100. In practical applications, the design can be flexibly adjusted according to the requirements.

[0072] In yet another example, refer to Figure 5 As shown, a single segmented cell 110 is 1 / 9 of the whole solar cell 100.

[0073] It should be noted that the above Figures 3-5 The three examples shown are all examples of a single solar cell 100 being divided into at least two individual cell segments 110. In practical applications, the number N of cell segments 110 formed by dividing the single solar cell 100 can be adjusted according to requirements. For example, N can also be 3, 5, 6, 7, 8, or 10. Furthermore, this embodiment of the present disclosure does not limit the segmentation path of the single solar cell 100 and can be flexibly adjusted according to requirements.

[0074] In the various embodiments described above, reference is made to Figures 2-5 ,as well as Figure 10 As shown, in a portion of the segmented cells 110, the area of ​​the sub-front side 110a can be larger than the area of ​​the sub-back side 110b. At least one cross-section 110c and the sub-back side 110b form a first included angle β. The supplementary angle of the first included angle β is an acute angle, that is, the first included angle β formed between the cross-section 110c and the sub-back side 110b is an obtuse angle, and an acute angle is also formed between the planes where the cross-section 110c and the sub-back side 110b are located.

[0075] In the various embodiments described above, reference is made to Figures 2-5 ,as well as Figure 10 As shown, in another portion of the segmented cells 110, the area of ​​the sub-front side 110a can be smaller than the area of ​​the sub-back side 110b, and at least one cross-section 110c and the sub-back side 110b form a second included angle γ, which is an acute angle, and an obtuse angle is also formed between the planes where the cross-section 110c and the sub-back side 110b are located.

[0076] It should be noted that in practical applications, for a cell with at least two cross sections, some cross sections form an acute angle with the back side of the cell, while other cross sections form an obtuse angle with the back side of the cell. In this case, the area of ​​the front side of the cell may be equal to the area of ​​the back side of the cell.

[0077] It is worth noting that in the various embodiments described above, reference is made to... Figures 2-5 ,as well as Figure 10 As shown, for any cross section 110c, the included angle formed between the cross section 110c and its corresponding sub-back face 110b is either an acute angle or an obtuse angle.

[0078] In the various embodiments described above, reference is made to Figures 3-5 The orthographic projection of the segmented battery 110 onto the back surface 110b can be rectangular, with the corners of some rectangles rounded 100c.

[0079] In one or more embodiments, the acute angle ranges from 45° to 80°. For example, the specific angle of the acute angle can be 45°, 50°, 55°, 60°, 65°, 70°, 75°, or 80°. (See reference) Figure 2 As shown, if the acute angle γ is less than 45°, the inclination of the cross-section 110c relative to the sub-back face 110b is too large. In this case, the part of the segmented cell 110 including the cross-section 110c can be regarded as a tip protruding from the entire segmented cell 110. The smaller the acute angle, the more protruding the tip, and the easier it is for the tip to break under pressure, which is not conducive to improving the structural stability of the segmented cell 110. If the acute angle is greater than 80°, the inclination of the cross-section 110c relative to the sub-back face 110b is too small, which is not conducive to reducing the atomic arrangement density on the cross-section 110c, and therefore not conducive to improving the passivation effect of the passivation layer 101 on the cross-section 110c. Therefore, designing the acute angle to be 45°-80° and controlling the tilt of the cross-section 110c relative to the sub-back face 110b is beneficial to improving the structural stability of the segmented battery 110 and reducing the probability of the segmented battery 110 being damaged, while effectively reducing the atomic arrangement density on the cross-section 110c, so as to improve the passivation effect of the passivation layer 101 on the cross-section 110c.

[0080] In one or more embodiments, reference is made to Figure 12 As shown, along the third direction Z, the passivation layer 101 includes at least a first passivation layer 111 and a second passivation layer 121 stacked together. The first passivation layer 111 contains silicon oxide material, and the second passivation layer 121 contains metal oxide material. The metal element in the metal oxide material includes at least one of Al (aluminum), Ti (titanium), Zn (zinc), Zr (zirconium), Hf (hafnium), Mo (molybdenum), W (tungsten), or Ni (nickel). The third direction Z is perpendicular to the cross section 110c.

[0081] Thus, for reference Figure 12 As shown, on one hand, the first passivation layer 111 is designed to contain silicon oxide material, which chemically passivates the cross-section 110c. For example, the first passivation layer 111 and the oxygen atom saturated cross-section 110c enhance the ability of the dangling bonds on the oxygen atom saturated cross-section 110c by means of the cross-section 110c tilted relative to the back face 110b, so as to further reduce the defect state density of the cross-section 110c and further reduce the recombination centers of the cross-section 110c to reduce the carrier recombination probability. On the other hand, the second passivation layer 121 is designed to contain metal oxide material, and the metal element in the metal oxide material includes Al and T. The second passivation layer 121, using at least one of the elements i, Zn, Zr, Hf, Mo, W, or Ni, possesses a high density of fixed charges. This high density of fixed charges generates a large electric field, effectively passivating the cross-section 110c through a field effect. For example, it creates a significant bandgap between the second passivation layer 121 and the cross-section 110c, hindering minority carrier migration to the cross-section 110c and reducing the minority carrier concentration there. This, in turn, helps reduce the recombination probability of majority and minority carriers at the cross-section 110c. Thus, the first passivation layer 111 and the second passivation layer 121 work together, and the cross-section 110c, which is tilted relative to the back surface 110b, significantly improves the photoelectric conversion efficiency of the segmented cell 110, thereby increasing the photoelectric conversion efficiency of the solar cell.

[0082] In addition, refer to Figure 12 As shown, due to the high density of silicon oxide material, it is beneficial to improve the density of the first passivation layer 111, resulting in high film stability of the first passivation layer 111. This is beneficial to protect the section 110c covered by the first passivation layer 111 through the first passivation layer 111, for example, it can prevent external impurities from invading the section 110c.

[0083] Furthermore, silicon oxide materials exhibit good resistance to PID (potential-induced degradation). Since the encapsulation materials of photovoltaic modules formed from solar cells cannot achieve 100% isolation from the external environment, moisture can enter the solar cell through the encapsulation material or backsheet used for sealing in humid environments. In this case, sodium ions are generated in the glass of the encapsulation material. Under the influence of an applied electric field, these sodium ions migrate towards the surface of the solar cell, causing PID and reducing the photoelectric conversion efficiency of the solar cell. Silicon oxide materials, with their excellent density and insulation properties, are effective in preventing moisture from entering the cross-section and then the individual cells, thus providing good resistance to PID. Therefore, even if the encapsulation material of the photovoltaic module cannot achieve complete insulation, and moisture enters the environment of the solar cell through the encapsulation material used for sealing, the silicon oxide film can prevent sodium ions in the glass of the encapsulation material from migrating towards the cross-section, thereby preventing PID and maintaining a high photoelectric conversion efficiency of the solar cell.

[0084] In some cases, the first passivation layer 111 and the second passivation layer 121 are stacked on the cross section 110c along the direction perpendicular to the first direction X, i.e., direction Z. In this case, the first passivation layer 111 is closer to the cross section 110c than the second passivation layer 121. For example, the first passivation layer 111 can cover the cross section 110c. This shortens the migration path of oxygen atoms in the first passivation layer 111 to the surface defects on the cross-section 110c, thereby improving the chemical passivation effect of oxygen atoms in the first passivation layer 111 on the cross-section 110c. Moreover, compared with the second passivation layer 121 containing metal oxide material, the lattice of the first passivation layer 111 containing silicon oxide material is more compatible with the lattice of the substrate in the segmented cell 110. This helps to avoid the problem of large lattice mismatch between the cross-section 110c and the second passivation layer 121 when they are in direct contact, thus avoiding the problem of increased surface defects caused by lattice mismatch and improving the interface passivation effect on the cross-section 110c.

[0085] The following provides an example of the metal oxide material contained in the second passivation layer.

[0086] In some examples, refer to Figure 12As shown, the metal element in the metal oxide material includes Al, that is, the second passivation layer 121 contains aluminum oxide material. On the one hand, the alumina material gives the second passivation layer 121 a high density of fixed negative charges (Qf is approximately 10¹² cm⁻² - 10¹³ cm⁻²), which is beneficial to improving the field passivation effect of the second passivation layer 121 on the cross section 110c, thereby reducing the probability of carrier recombination at the cross section 110c and thus improving the photoelectric conversion efficiency of the segmented cell 110. On the other hand, in the technique of forming the second passivation layer 121 containing alumina material, the second passivation layer 121 also contains an appropriate amount of hydrogen ions, which gives the second passivation layer 121 a good hydrogen passivation effect on the cross section 110c. For example, the appropriate amount of hydrogen ions in the second passivation layer 121 can both effectively saturate the dangling bonds on the cross section 110c by migration and suppress recombination with carriers, which is beneficial 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.

[0087] In other examples, refer to Figure 12 As shown, the metal element in the metal oxide material includes Mo, meaning the second passivation layer 121 contains molybdenum oxide. On one hand, the molybdenum oxide material gives the second passivation layer 121 a high work function, which also helps the second passivation layer 121 to have a good field passivation effect on the cross-section 110c. On the other hand, the technique for forming the second passivation layer 121 containing molybdenum oxide also ensures that the second passivation layer 121 contains an appropriate amount of hydrogen ions, giving the second passivation layer 121 a good hydrogen passivation effect on the cross-section 110c.

[0088] It should be noted that the above two examples illustrate the good passivation effect of the metal oxide material in the second passivation layer on the cross-section. 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 second passivation layer a high density of fixed negative charge to achieve a good field passivation effect on the cross-section; the metal element in the metal oxide material includes at least one of Mo, W, or Ni, which can give the second passivation layer a high density of fixed positive charge or a high work function to achieve a good field passivation effect on the cross-section 110c.

[0089] In one or more embodiments, reference is made to Figure 13 As shown, the passivation layer 101 may further include an intermediate passivation layer 131, which is located between the first passivation layer 111 and the second passivation layer 121. Both the intermediate passivation layer 131 and the first passivation layer 111 contain silicon, and the intermediate passivation layer 131 and the second passivation layer 121 contain the same metal element.

[0090] It is worth noting that, reference Figure 13 As shown, the intermediate passivation layer 131 not only shares the same element as the first passivation layer 111 (i.e., silicon) but also shares the same element as the second passivation layer 121 (i.e., metal). Thus, the intermediate passivation layer 131 not only benefits from the silicon element to achieve a better lattice fit at the interface where it contacts the first passivation layer 111, but also benefits from the metal element to achieve a better lattice fit at the interface where it contacts the second passivation layer 121. This helps avoid the problem of large lattice mismatch between the first and second passivation layers 111 and 121 when they are in direct contact, thus preventing an increase in surface defects caused by lattice mismatch. This improves the passivation effect of the passivation layer 101 on the interface of the segmented battery 110, for example, improving the passivation effect on the cross-section 110c.

[0091] In other words, reference Figure 13 As shown, the intermediate passivation layer 131 serves as a transition layer to improve the lattice fit at the interface where the first passivation layer 111, the intermediate passivation layer 131, and the second passivation layer 121 are in sequential contact. This prevents voids and misalignments at the interface, thereby improving the uniformity of the passivation layer 101 itself and enhancing its passivation effect on the segmented battery 110. Furthermore, the intermediate passivation layer 131 helps to improve the connection strength between the first passivation layer 111 and the intermediate passivation layer 131, as well as the connection strength between the intermediate passivation layer 131 and the second passivation layer 121. This prevents slippage or detachment of the first passivation layer 111 and the intermediate passivation layer 131, or between the intermediate passivation layer 131 and the second passivation layer 121, thus improving the structural stability of the passivation layer 101. In this way, it can be ensured that the intermediate passivation layer 131 has the same elements as the first passivation layer 111 and the second passivation layer 121, so that the intermediate passivation layer 131 serves as a transition layer between the first passivation layer 111 and the second passivation layer 121. Furthermore, the oxygen atoms in the intermediate passivation layer 131 can be utilized to further saturate the dangling bonds on the cross-section 110c based on the migration of these oxygen atoms toward the cross-section 110c, thereby further reducing the defect state density of the cross-section 110c and further reducing the recombination centers of the cross-section 110c to reduce the carrier recombination probability.

[0092] In some embodiments, combined with Figure 14 and Figure 15As shown, the intermediate passivation layer 131 and the first passivation layer 111 have a first surface e in contact with each other, and the intermediate passivation layer 131 and the second passivation layer 121 have a second surface f in contact with each other; wherein, the content of silicon element at the first surface e is higher than the content at the second surface f, and the content of metal element at the first surface e is lower than the content at the second surface f.

[0093] Combination Figure 14 and Figure 15 As shown, on the one hand, the first passivation layer 111 contains silicon oxide material. Based on this, the silicon content at the first surface e where the intermediate passivation layer 131 contacts the first passivation layer 111 is higher than that at the second surface f. Compared with the second surface f, it is beneficial to enrich silicon at the first surface e. This is beneficial to further improve the lattice fit at the interface where the intermediate passivation layer 131 contacts the first passivation layer 111 by increasing the silicon content at the first surface e, further reduce the defect state density at the first surface e, and thus further improve the passivation effect of the passivation layer 101 on the cross section 110c. On the other hand, the second passivation layer 121 contains a metal oxide material. Based on this, the content of metal elements at the second surface f where the intermediate passivation layer 131 and the second passivation layer 121 are in contact is designed to be higher than that at the first surface e. This is beneficial to enrich the metal elements at the second surface f, thereby improving the lattice fit at the interface where the intermediate passivation layer 131 and the second passivation layer 121 are in contact by increasing the content of metal elements at the second surface f, further reducing the defect state density at the second surface f, and thus further improving the passivation effect of the passivation layer 101 on the cross section 110c.

[0094] In some embodiments, combined with Figure 14 and Figure 15 As shown, along the direction Z from the first passivation layer 111 to the second passivation layer 121, the content of silicon in the intermediate passivation layer 131 shows a decreasing trend, while the content of metal elements in the intermediate passivation layer 131 shows an increasing trend. In some cases, the direction Z from the first passivation layer 111 to the second passivation layer 121 is perpendicular to the cross-section 110c; in other words, direction Z is perpendicular to the first direction X.

[0095] It is worth noting that the silicon content at the first surface e is higher than that at the second surface f, and the metal content at the first surface e is lower than that at the second surface f. Therefore, along the direction from the first passivation layer 111 to the second passivation layer 121, this helps ensure that the silicon content in the intermediate passivation layer 131 decreases while the metal content in the intermediate passivation layer 131 increases. Furthermore, the gradual change in both silicon and metal content in the intermediate passivation layer 131 is beneficial for improving the performance stability of the intermediate passivation layer 131 and avoiding performance abrupt changes caused by sudden changes in element content within the intermediate passivation layer 131.

[0096] In some embodiments, combined with Figure 14 and Figure 15 As shown, the intermediate passivation layer 131 may also contain oxygen elements. Along the direction Z from the first passivation layer 111 to the second passivation layer 121, the content of oxygen elements in the intermediate passivation layer 131 first increases and then decreases.

[0097] It is worth noting that, in order to improve the lattice compatibility at the interface between the intermediate passivation layer 131 and the first passivation layer 111, and to improve the lattice compatibility at the interface between the intermediate passivation layer 131 and the second passivation layer 121, silicon is enriched at the first surface e where the intermediate passivation layer 131 contacts the first passivation layer 111, and metal is enriched at the second surface f where the intermediate passivation layer 131 contacts the second passivation layer 121. Therefore, along the direction from the first passivation layer 111 to the second passivation layer 121, the peak oxygen content in the intermediate passivation layer 131 is located in the middle portion, ensuring that one end of the intermediate passivation layer 131 is rich in silicon and the other is rich in metal. Based on this, the oxygen content in the intermediate passivation layer 131 is designed to first increase and then decrease to ensure a high passivation effect of the passivation layer 101 on the cross-section 110c.

[0098] It should be noted that, in some embodiments, an increasing trend of a parameter means that the parameter gradually increases, that is, the parameter consistently increases throughout the change process; a decreasing trend of a parameter means that the parameter gradually decreases throughout the change process. In other embodiments, an increasing trend of a parameter means that the parameter generally increases during the change process, but gradually decreases in some localized areas; a decreasing trend of a parameter means that the parameter generally decreases during the change process, but gradually increases in some localized areas. In other embodiments, an increasing trend of a parameter can mean that the parameter gradually increases, and a decreasing trend of a parameter can mean that the parameter generally decreases, but gradually increases in some localized areas; or, an increasing trend of a parameter can mean that the parameter generally increases, but gradually decreases in some localized areas, and a decreasing trend of a parameter simply means that the parameter gradually decreases. The above parameters include, but are not limited to, the content of silicon in the intermediate passivation layer 131, the content of metal in the intermediate passivation layer 131, and the content of oxygen in the intermediate passivation layer 131.

[0099] also, Figure 15 This is merely an example of the variation trend of the content ratio of silicon, metal, and oxygen in a portion of the cell 110 and passivation layer 101 within a segmented battery. In practical applications, the variation trend of the content ratio of silicon, metal, and oxygen in the cell 110 and passivation layer 101 can also be partially or completely similar. Figure 15 The examples shown are different. In one example Figure 15 The metallic element in it can be aluminum.

[0100] In some embodiments, the intermediate passivation layer 131 may be a common oxide of silicon and aluminum, and the second passivation layer 121 may be an aluminum oxide material.

[0101] In some embodiments, reference Figure 14 As shown, along the direction Z from the first passivation layer 111 to the second passivation layer 121, the thickness D1 of the first passivation layer 111 is less than the thickness D3 of the intermediate passivation layer 131, and the thickness D3 of the intermediate passivation layer 131 is less than the thickness D2 of the second passivation layer 121.

[0102] refer to Figure 14As shown, the first passivation layer 111 contains silicon oxide material. When the thickness of the silicon oxide film along the Z direction, i.e., D1, is small, it can ensure that the first passivation layer 111 has a good chemical passivation effect on the cross-section 110c. Moreover, compared with forming a thicker first passivation layer 111, the formation process of the first passivation layer 111 with a smaller D1 is simpler. In addition, when the thickness D1 of the first passivation layer 111 is small, it is also beneficial for oxygen atoms in the intermediate passivation layer 131 to migrate more easily to the cross-section 110c, so as to further improve the chemical passivation effect on the cross-section 110c.

[0103] refer to Figure 14 As shown, the intermediate passivation layer 131 serves as a transition layer between the first passivation layer 111 and the second passivation layer 121. The thickness D3 of the intermediate passivation layer 131 along the Z direction is appropriate, preferably facilitating the migration of oxygen atoms in the intermediate passivation layer 131 to the cross-section 110c. Furthermore, the second passivation layer 121 comprises a metal oxide material. Along the Z direction, within a certain thickness range, the greater the thickness of the film containing the metal oxide material, the better the field-effect passivation effect of the second passivation layer 121 on the cross-section 110c. Therefore, along the Z direction, the thickness D2 of the second passivation layer 121 is the largest, the thickness D1 of the first passivation layer 111 is the smallest, and the thickness D3 of the intermediate passivation layer 131 is between D1 and D2. This design ensures that the first passivation layer 111 has a good chemical passivation effect on the cross section 110c, and the second passivation layer 121 has a good field effect passivation effect on the cross section 110c. It also facilitates the migration of oxygen atoms in the intermediate passivation layer 131 to the cross section 110c.

[0104] In some embodiments, reference Figure 14 As shown, along the Z direction, the thickness D1 of the first passivation layer 111 can be 1nm-10nm. In some examples, the thickness D1 of the first passivation layer 111 can be 4nm-7nm, such as 4.5nm, 5nm, 5.5nm, 6nm, or 6.5nm.

[0105] In some embodiments, reference Figure 14 As shown, along the Z direction, the thickness D2 of the second passivation layer 121 can be 20nm-100nm. In some examples, the thickness D2 of the second passivation layer 121 can be 40nm-60nm, such as 45nm, 48nm, 50nm, 53nm, 55nm, or 58nm.

[0106] In some embodiments, reference Figure 14As shown, along the Z direction, the thickness D3 of the intermediate passivation layer 131 can be 4nm-15nm. In some examples, the thickness D3 of the intermediate passivation layer 131 can be 8nm-12nm, such as 8.5nm, 9nm, 9.5nm, 10nm, 10.5nm, 11nm, or 11.5nm.

[0107] In some embodiments, the intermediate passivation layer may further contain oxygen, and the silicon content in the intermediate passivation layer is 2%-60%, the metal content is 2%-50%, and the oxygen content is 38%-50%.

[0108] It should be noted that the silicon content ratio of 2%-60% in the intermediate passivation layer refers to the average value of the silicon content ratio within the intermediate passivation layer, which may or may not fall within this average value. Similarly, the metal content ratio of 2%-50% in the intermediate passivation layer refers to the average value of the metal content ratio within the intermediate passivation layer, which may or may not fall within this average value. Likewise, the oxygen content ratio of 38%-50% in the intermediate passivation layer refers to the average value of the oxygen content ratio within the intermediate passivation layer, which may or may not fall within this average value.

[0109] In some cases, refer to Figure 14 As shown, for the region with the highest silicon content in the intermediate passivation layer 131, such as the first surface e, the silicon content in this region is 40%-80%, for example, the silicon content in this region can be 60%; for the region with the lowest silicon content in the intermediate passivation layer 131, such as the second surface f, the silicon content in this region is 2%-5%, for example, the silicon content in this region can be 3%.

[0110] In some cases, refer to Figure 14 As shown, for the region with the smallest proportion of metal element content in the intermediate passivation layer 131, such as the first surface e, the proportion of metal element content in this region is 2%-5%, for example, the proportion of metal element content in this region can be 3%; for the region with the largest proportion of metal element content in the intermediate passivation layer 131, such as the second surface f, the proportion of metal element content in this region is 30%-70%, for example, the proportion of metal element content in this region can be 50%.

[0111] In some cases, refer to Figure 14As shown, for the region with the highest oxygen content in the intermediate passivation layer 131, such as the middle region of the intermediate passivation layer 131, the oxygen content in this region is 45%-60%, for example, the oxygen content in this region can be 60%; for the region with the lowest oxygen content in the intermediate passivation layer 131, such as the first surface e or the second surface f, the oxygen content in this region is 20%-40%, for example, the oxygen content in this region can be 20%.

[0112] It should be noted that the reference Figure 14 As shown, for the intermediate passivation layer 131, the sum of the proportions of silicon, metal, and oxygen can be 100% or not. When the sum of these proportions is not 100%, the intermediate passivation layer 131 also contains other impurity elements, such as hydrogen, giving it a hydrogen passivation effect on the cross-section 110c. It is worth noting that in the technique for forming the second passivation layer 121, it is possible that the second passivation layer 121 contains other impurity elements besides silicon, oxygen, and metal.

[0113] In some embodiments, combined with Figure 14 and Figure 15 As shown, along direction Z, the first passivation layer 111 has a third surface g away from the second passivation layer 121 and a first surface e close to the second passivation layer 121; wherein, the content of silicon element at the third surface g is higher than that at the first surface e, and the content of oxygen element at the third surface g is lower than that at the first surface e.

[0114] Combination Figure 14 and Figure 15 As shown, the third surface g is the interface where the first passivation layer 111 and the cross-section 110c meet. Most of the area of ​​the cross-section 110c is formed by the side surface of the substrate 160 in the segmented cell 110. The substrate 160 can be a silicon substrate material. Based on this, the silicon content at the third surface g where the first passivation layer 111 and the cross-section 110c meet is designed to be higher than that at the first surface e. Compared to the first surface e, this is beneficial for enriching silicon at the third surface g. Therefore, by increasing the silicon content at the third surface g, the lattice fit at the interface between the first passivation layer 111 and the cross-section 110c is further improved, and the defect state density at the third surface g is further reduced, thereby further improving the passivation effect of the first passivation layer 111 on the cross-section 110c. Furthermore, to ensure that the silicon content at the third surface g is higher than that at the first surface e, the oxygen content at the third surface g is designed to be lower than that at the first surface e, thus guaranteeing a higher passivation effect of the first passivation layer 111 on the cross-section 110c.

[0115] In some embodiments, combined with Figure 14 and Figure 15 As shown, along the Z-direction from the first passivation layer 111 to the second passivation layer 121, the silicon content in the first passivation layer 111 shows a decreasing trend, while the oxygen content in the first passivation layer 111 shows an increasing trend. Thus, both silicon and oxygen content in the first passivation layer 111 exhibit a gradual change, which is beneficial for improving the performance stability of the first passivation layer 111 and avoiding performance abrupt changes caused by sudden changes in element content within the first passivation layer 111.

[0116] It should be noted that the foregoing has already described in detail the terms "increasing trend", "specific situations included in increasing trend", "decreasing trend" and "specific situations included in decreasing trend". Therefore, the descriptions of the decreasing trend of silicon content and the increasing trend of oxygen content in the first passivation layer 111 will not be repeated here.

[0117] In some embodiments, reference Figure 14 As shown, along direction Z, the second passivation layer 121 has a fourth surface h away from the first passivation layer 111 and a second surface close to the first passivation layer 111; wherein, the content of oxygen at the second surface f is higher than that at the fourth surface h, and the content of the metal element at the second surface f is lower than that at the fourth surface h.

[0118] refer to Figure 14 As shown, whether the first passivation layer 111 and the second passivation layer 121 are in direct contact, or there is an intermediate passivation layer 131 between the first passivation layer 111 and the second passivation layer 121, the oxygen content at the second surface f is designed to be higher than that at the fourth surface h. Compared to the fourth surface h, this is beneficial for enriching oxygen at the second surface f, thereby making it easier for more oxygen atoms to migrate to the cross-section 110c, thus improving the passivation effect of the passivation layer 101 on the cross-section 110c. Moreover, in order to ensure that the oxygen content at the second surface f is higher than that at the fourth surface h, the metal content at the second surface f is designed to be lower than that at the fourth surface h, so as to ensure a higher passivation effect of the second passivation layer 121 on the cross-section 110c.

[0119] In some embodiments, combined with Figure 14 and Figure 15As shown, along the Z-direction from the first passivation layer 111 to the second passivation layer 121, the oxygen content in the second passivation layer 121 shows a decreasing trend, while the metal content shows an increasing trend. Thus, both the oxygen and metal content in the second passivation layer 121 exhibit a gradual change, which is beneficial for improving the performance stability of the second passivation layer 121 and avoiding performance abrupt changes caused by sudden changes in element content within the second passivation layer 121.

[0120] It should be noted that the foregoing has already described in detail the terms "increasing trend", "specific circumstances included in increasing trend", "decreasing trend" and "specific circumstances included in decreasing trend". Therefore, the descriptions of the decreasing trend of oxygen content and the increasing trend of metal content in the second passivation layer 121 will not be repeated here.

[0121] In some embodiments, the silicon content in the first passivation layer is 60%-98%, and the oxygen content is 2%-40%.

[0122] It should be noted that the silicon content ratio of 60%-98% in the first passivation layer refers to the average value of the silicon content ratio within the first passivation layer, which may or may not fall within this average value. Similarly, the oxygen content ratio of 2%-40% in the first passivation layer refers to the average value of the oxygen content ratio within the first passivation layer, which may or may not fall within this average value.

[0123] In some cases, refer to Figure 14 As shown, for the region with the highest silicon content in the first passivation layer 111, such as the third surface g, the silicon content in this region is 90%-98%, for example, the silicon content in this region can be 95%; for the region with the lowest silicon content in the first passivation layer 111, such as the first surface e, the silicon content in this region is 40%-80%, for example, the silicon content in this region can be 60%.

[0124] In some cases, refer to Figure 14 As shown, for the region with the smallest oxygen content in the first passivation layer 111, such as the third surface g, the oxygen content in this region is 2%-5%, for example, the oxygen content in this region can be 3%; for the region with the largest oxygen content in the first passivation layer 111, such as the first surface e, the oxygen content in this region is 20%-60%, for example, the oxygen content in this region can be 40%.

[0125] It should be noted that the sum of the silicon and oxygen content percentages in the first passivation layer can be 100% or not. When the sum of the silicon and oxygen content percentages is not 100%, the first passivation layer also contains other impurity elements, such as hydrogen, giving it a hydrogen passivation effect on the cross-section. It is worth noting that the technology used to form the first passivation layer may result in the presence of other impurity elements besides silicon, oxygen, and metal elements within the first passivation layer.

[0126] In some embodiments, the content of metal elements in the second passivation layer is 45%-65%, and the content of oxygen elements is 35%-55%.

[0127] It should be noted that the 45%-65% metal element content ratio in the second passivation layer refers to the average value of the metal element content ratio within the second passivation layer, which may or may not fall within this average value. Similarly, the 35%-55% oxygen element content ratio in the second passivation layer refers to the average value of the oxygen element content ratio within the second passivation layer, which may or may not fall within this average value.

[0128] In some cases, refer to Figure 14 As shown, for the region with the largest proportion of metal element content in the second passivation layer 121, such as the fourth surface h, the proportion of metal element content in this region is 55%-75%, for example, the proportion of metal element content in this region can be 70%; for the region with the smallest proportion of metal element content in the first passivation layer 111, the proportion of metal element content in this region is 25%-50%, for example, the proportion of metal element content in this region can be 30%.

[0129] In some cases, refer to Figure 14 As shown, for the region with the smallest oxygen content in the second passivation layer 121, the oxygen content in this region is 25%-45%, for example, the oxygen content in this region can be 30%; for the region with the largest oxygen content in the second passivation layer 121, the oxygen content in this region is 50%-70%, for example, the oxygen content in this region can be 55%.

[0130] It should be noted that the reference Figure 14As shown, for the second passivation layer 121, the sum of the silicon content and the metal content can be 100% or not. When the sum of the silicon content and the metal content is not 100%, the second passivation layer 121 also contains other impurity elements, such as hydrogen, giving the second passivation layer 121 a hydrogen passivation effect on the cross-section 110c. It is worth noting that the technique for forming the second passivation layer 121 may result in the presence of other impurity elements besides silicon, oxygen, and metal.

[0131] In some embodiments, the first passivation layer may be Si a O b The material, a / b∈[1.5, 49], where a / b represents the ratio of silicon and oxygen content in the first passivation layer.

[0132] In some embodiments, the intermediate passivation layer may be SiAl i O j The material, i / j∈[0.04, 1.31], where i / j represents the ratio of aluminum and oxygen content in the intermediate passivation layer.

[0133] In some embodiments, the second passivation layer may be Al m O n The material is m / n∈[1,1.2], where m / n represents the ratio of aluminum to oxygen content in the second passivation layer.

[0134] It should be noted that the mathematical formula Si containing "a" and "b" in this article a O b This represents the elemental ratio of silicon to oxygen in the first passivation layer. The mathematical formula SiAl in this paper contains "i" and "j". i O j This indicates the elemental ratio of aluminum to oxygen in the second passivation layer. The mathematical formula containing "m" and "n" in this text is Al. m O n This indicates the elemental ratio of aluminum to oxygen in the intermediate passivation layer, Si. a O b SiAl i O j And Al m O n Neither of them are strict chemical formulas or chemical structures, therefore Si a O b Materials, SiAl i O j Materials and Al m O nThe materials may include one or more stoichiometric compounds and / or one or more non-stoichiometric compounds, and the values ​​of “a” and “b” (if present) may be integers or non-integers, the values ​​of “i” and “j” (if present) may also be integers or non-integers, and the values ​​of “m” and “n” (if present) may also be integers or non-integers.

[0135] As used herein, the term "non-stoichiometric compound" refers to and includes compounds composed of a single element that cannot be expressed by a well-defined ratio of natural numbers and does not violate the law of definite proportions. The content of each element in the first passivation layer, the second passivation layer, and the intermediate passivation layer can be confirmed by measurements such as X-ray energy dispersive spectroscopy (EDS), electron energy loss spectroscopy (EELS), or secondary ion mass spectrometry (SIMS). For example, specific line regions or area regions can be selected for testing using measuring equipment.

[0136] In some embodiments, the segmented cell may include an IBC cell (Interdigitated Back Contact), a TOPCON (Tunnel Oxide Passivated Contact) cell, or a PERC cell (Passivated emitter and real cell).

[0137] In some embodiments, reference Figures 3-5 At least a portion of the cell 110 has an undivided side 110d; Reference Figure 16 As shown, the segmented battery 110 includes: a substrate 120 having a first surface 120a and a second surface 120b opposite to each other along a second direction Y; a first passivation film 130 located on the first surface 120a; a second passivation film 140 located on the second surface 120b; and a side passivation film 150 located on a side surface 110d. The side passivation film 110d and the first passivation film 130 contain the same material, or the side passivation film 110d and the second passivation film 140 contain the same material.

[0138] It should be noted that the reference Figures 3-5 Each cell segment 110 has an undivided side 110d. In practical applications, some cell segments 110 have four sides that are divided into sections 110c, for example, see reference... Figure 5The entire solar cell 100 is divided into 9 sub-cells 110 in a 3*3 array arrangement. The four sides of the sub-cell 110 located in the middle are all cross sections 110c.

[0139] In some examples, refer to Figure 16 As shown, the side passivation film 150, the first passivation film 130 and the second passivation film 140 contain the same material. Therefore, the side passivation film 150, the first passivation film 130 and the second passivation film 140 can be formed by the same preparation process, which is beneficial to simplify the preparation process and reduce the preparation cost of the side passivation film 150, the first passivation film 130 and the second passivation film 140.

[0140] In other examples, refer to Figure 16 As shown, the first passivation film 130 and the second passivation film 140 can also be formed by different preparation processes, and the side passivation film 150 can be formed by the same preparation process as the first passivation film 130 and the second passivation film 140.

[0141] It should be noted that the reference Figure 16 As shown, the specific structure of the side passivation film 150 is different from that of the passivation layer 101. For example, the side passivation film 150 is a single-layer structure, which is different from the stacked structure of the passivation layer 101; or, the side passivation film 150 is also a stacked structure, but the material of at least some of the film layers in the side passivation film 150 is different from the material of at least some of the film layers in the passivation layer 101.

[0142] In some cases, refer to Figure 16 As shown, the side passivation film 150 and the passivation layer 101 are not formed by the same preparation process.

[0143] In some embodiments, reference Figure 16 As shown, the side passivation film 150 can be a stacked structure of a first side passivation film, a second side passivation film, and a third side passivation film stacked along a direction perpendicular to the second direction Y. In one example, the material of the first side passivation film may include silicon, the material of the second side passivation film may include aluminum oxide, and the material of the third side passivation film may include silicon nitride; wherein, along the direction perpendicular to the second direction Y, the thickness of the second side passivation film may be 5 nm.

[0144] In some embodiments, reference Figure 16 As shown, the side passivation film 150 can be a single-layer structure, and the material of the side passivation film 150 includes silicon oxynitride. In one example, the thickness of the side passivation film 150 in the direction perpendicular to the second direction Y can be 70 nm.

[0145] The following explanation uses TOPCON batteries as an example of segmented batteries.

[0146] In some embodiments, reference Figure 17 As shown, the substrate 120 may include: a substrate 160 having a third surface 160a and a fourth surface 160b opposite each other along the second direction Y, the third surface 160a being closer to the first surface 120a and the fourth surface 160b being closer to the second surface 120b; an emitter 170 located on the third surface 160a; a tunneling dielectric layer 180 located on the fourth surface 160b; and a doped conductive layer 190 located on the side of the tunneling dielectric layer 180 away from the fourth surface 160b. A first passivation film 130 is located on the side of the emitter 170 away from the third surface 160a, and a second passivation film 140 is located on the side of the doped conductive layer 190 away from the tunneling dielectric layer 180. The cross-section 110c is... Figure 6 The silicon surface shown is hydroxylated.

[0147] In some cases, refer to Figure 17 As shown, substrate 160 is a silicon substrate material, such as one or more of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. In some examples, substrate 160 can be an N-type semiconductor substrate, and substrate 160 may include N-type doping elements (such as phosphorus, arsenic, antimony, etc.). Emitter 170 may contain P-type doping elements, and emitter 170 forms a PN junction with substrate 160.

[0148] In some cases, refer to Figure 17 As shown, the segmented battery 110 may further include a first electrode 122, which is in electrical contact with the emitter 170. In one example, the first electrode 122 penetrates the first passivation film 130 and is in electrical contact with the emitter 170.

[0149] In some cases, refer to Figure 17 As shown, the segmented cell 110 may further include a second electrode 123, which is in electrical contact with the doped conductive layer 190. In one example, the second electrode 123 penetrates the second passivation film 140 and is in electrical contact with the doped conductive layer 190.

[0150] In the above various embodiments, in some embodiments, both the first passivation film and the second passivation film can be a single-layer structure or a stacked structure, and the materials of the first passivation film 130 and the second passivation film 140 can be at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, titanium oxide, hafnium oxide or aluminum oxide.

[0151] This disclosure also provides a photovoltaic module for converting received light energy into electrical energy. (See reference...) Figure 18 and Figure 19As shown, the photovoltaic module includes: a battery string, which is formed by connecting multiple solar cells 40 formed by the preparation method provided in the foregoing embodiments, or formed by connecting multiple solar cells 40 provided in the foregoing embodiments; an encapsulating film 41 for covering the surface of the battery string; and a cover plate 42 for covering the surface of the encapsulating film 41 facing away from the battery string.

[0152] It should be noted that solar cells are electrically connected to form multiple cell strings, which are connected in series and / or parallel. Since solar cells include segmented cells, and these segmented cells are formed by dividing a whole solar cell, the reduced current in the segmented cells can improve the power loss of the photovoltaic module, thereby increasing the photoelectric conversion efficiency of the photovoltaic module.

[0153] In one or more embodiments, reference is made to Figure 19 As shown, multiple battery strings can be electrically connected through conductive strip 402. Figure 19 This illustration only depicts one possible positional relationship between solar cells, where the electrodes of the same polarity are arranged in the same direction, or where the positive electrode of each cell faces the same side, thus the conductive strip connects different sides of two adjacent cells. In some embodiments, the cells can also be arranged with electrodes of different polarities facing the same side, i.e., the electrodes of multiple adjacent cells are arranged in the order of first polarity, second polarity, and first polarity, respectively, then the conductive strip connects two adjacent cells on the same side.

[0154] In one or more embodiments, there is no gap between the solar cells, that is, the solar cells overlap each other.

[0155] In one or more embodiments, the encapsulating film includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front or back sides of the solar cell, and the second encapsulating layer covers the other of the front or back sides of the solar cell. Specifically, at least one of the first encapsulating layer or the second encapsulating layer can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, or polyethylene terephthalate (PET) film.

[0156] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After lamination, the photovoltaic module no longer has the concept of a first encapsulation layer and a second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film.

[0157] In one or more embodiments, the cover plate can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate facing the encapsulating film can be an uneven surface, thereby increasing the utilization rate of incident light. The cover plate includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0158] In one or more embodiments, reference is made to Figure 18 As shown, the solar cells 40 in the battery string are arranged along the direction U, and the main grids of two adjacent solar cells 40 in the battery string are staggered in the direction Y. For photovoltaic modules, by setting the main grids of two adjacent solar cells 40 in the battery string to be staggered in the direction Y, the different potentials of the photovoltaic modules can be tested, thereby improving the reliability of the test results.

[0159] In one or more embodiments, the photovoltaic cell includes, but is not limited to, one or any combination of PERC (Passivated Emitter Rear Cell), IBC (Interdigitated Back Contact), TOPCon (Tunnel Oxide Passivated Contact), HIT / HJT (Heterojunction Technology), thin-film solar cells, and tandem solar cells. Thin-film solar cells include, but are not limited to, perovskite thin-film solar cells, copper indium selenide (CIGS) thin-film solar cells, gallium arsenide (GaAs) thin-film solar cells, and cadmium sulfide (CdS) thin-film solar cells. Tandem solar cells include, but are not limited to, perovskite cells stacked with crystalline silicon cells, perovskite cells stacked with perovskite cells, and perovskite cells stacked with thin-film cells.

[0160] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this disclosure. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.

Claims

1. A solar cell, characterized by, The solar cell comprises: a sub-front surface and a sub-back surface oppositely arranged along a second direction, the second direction being a thickness direction of the solar cell, the solar cell further comprising a section surface connecting the sub-back surface and the sub-front surface, the section surface being a silicon surface with hydrogen-oxygen bonds; a passivation layer on the section surface.

2. The solar cell according to claim 1, characterized in that, An included angle formed by the section surface and the sub-back surface or the sub-front surface is an acute angle.

3. The solar cell according to claim 2, characterized in that, The acute angle ranges from 45° to 80°.

4. The solar cell of claim 1, wherein In a third direction perpendicular to the section surface, the passivation layer comprises at least a first passivation layer and a second passivation layer stacked, the first passivation layer comprising a silicon oxide material, and the second passivation layer comprising a metal oxide material, the metal element in the metal oxide material comprising at least one of Al, Ti, Zn, Zr, Hf, Mo, W or Ni.

5. The solar cell according to claim 4, characterized in that, The passivation layer further comprises an intermediate passivation layer between the first passivation layer and the second passivation layer, and the intermediate passivation layer and the first passivation layer both comprise a silicon element, and the intermediate passivation layer and the second passivation layer comprise the same metal element.

6. The solar cell according to claim 5, characterized in that, The material of the intermediate passivation layer comprises an oxide of the silicon element and the metal element.

7. The solar cell of claim 4, wherein In a direction from the first passivation layer to the second passivation layer, the content of the silicon element in the intermediate passivation layer decreases, and the content of the metal element in the intermediate passivation layer increases.

8. The solar cell of claim 4, wherein, The intermediate passivation layer further comprises an oxygen element, and in the direction from the first passivation layer to the second passivation layer, the content of the oxygen element in the intermediate passivation layer first increases and then decreases.

9. The solar cell of claim 4, wherein, In the direction from the first passivation layer to the second passivation layer, the thickness of the first passivation layer is less than the thickness of the intermediate passivation layer, and the thickness of the intermediate passivation layer is less than the thickness of the second passivation layer.

10. The solar cell of claim 1, wherein, The solar cell further comprises: a side surface connecting the sub-back surface and the sub-front surface; a base having a first surface and a second surface oppositely arranged along the second direction; a side surface passivation film on the side surface; a first passivation film on the first surface; a second passivation film on the second surface; wherein the material of the side surface passivation film is the same as the material of the first passivation film and / or the second passivation film.

11. A method of manufacturing a solar cell, characterized by, The method comprises: providing a whole solar cell; wherein the whole solar cell comprises a to-be-cut region; using a first laser device to form positioning grooves at two ends of the to-be-cut region; using a second laser device to heat the to-be-cut region from the positioning groove to another positioning groove. injecting a cooling liquid to the heated to-be-split region by a spraying device, so that the whole solar cell is cracked along a first direction in the to-be-split region to form at least two split cells; wherein the cooling liquid comprises an oxidizing substance, the split cell comprises a sub-front surface and a sub-back surface oppositely arranged along a second direction, and a fracture surface formed by the whole solar cell being cracked along the first direction, the second direction is a thickness direction of the split cell, the whole solar cell has a front surface and a back surface oppositely arranged along the second direction, the sub-front surface of at least two split cells formed based on the same whole solar cell is a partial region of the front surface, and the sub-back surface of at least two split cells formed based on the same whole solar cell is a partial region of the back surface; and the fracture surface is a silicon surface after surface hydroxylation; forming a passivation layer on the fracture surface.

12. The method of claim 11, wherein, The oxidizing substance comprises H2O2 or O3.

13. The method of claim 12, wherein, The concentration of the oxidizing substance in the cooling liquid ranges from 0.5% to 50%.

14. The method of claim 11, wherein, The spraying device comprises a nozzle. In the injecting a cooling liquid to the heated to-be-split region by a spraying device, the distance between the projection of the nozzle on the to-be-split region and the laser spot formed by the second laser device on the to-be-split region along the laser scanning direction ranges from 1 mm to 10 mm.

15. The preparation method according to claim 11, characterized in that, The laser temperature of the second laser device ranges from 150℃ to 250℃.

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