Solar cell and preparation method thereof

Abstract

The embodiment of the invention relates to the field of photovoltaic technology, and provides a solar cell and a preparation method thereof, so as to improve the photoelectric conversion efficiency of the solar cell comprising a fragmented cell, greatly reduce the mechanical damage of the fragmented cell, greatly reduce the hidden crack possibility of a photovoltaic module comprising the fragmented cell, and improve the production efficiency of the photovoltaic module. And the product yield is further improved. The preparation method of the solar cell comprises the following steps: providing a whole solar cell; a first laser device is adopted to form positioning grooves in the two ends of the to-be-segmented area respectively; a second laser device is adopted to heat the to-be-segmented area from the positioning groove until the other positioning groove is finished; spraying cooling liquid to the heated to-be-segmented area by adopting a spraying device, so that the whole solar cell is cracked in the to-be-segmented area along the first direction to form at least two segmented cells; the cooling liquid comprises oxidizing substances, and the cross section is a surface hydroxylated silicon surface; and forming a passivation layer on the fracture surface.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the field of photovoltaic technology, and in particular to a solar cell and a method for preparing the same. Background Art

[0002] In order to improve the energy density of photovoltaic modules, module technologies such as half-cell technology, stack welding technology, and shingling technology are constantly developing. These technologies require cutting the entire solar cell into half, one-third, or even smaller sizes to increase the effective power generation area, reduce power loss, and increase module power.

[0003] Currently, laser cutting technology is used to segment the entire solar cell. The laser cutting process includes: first, slotting is performed by laser ablation, and then the entire solar cell is broken at the slotted position by mechanical means. However, this process is prone to mechanical damage, and the photovoltaic module formed by the cut cell is prone to hidden cracks, thereby reducing the product yield; at the same time, there are dangling bonds on the cross section formed by cutting, which in turn forms an electron-hole recombination center, thereby reducing the photoelectric conversion efficiency of the cut cell, and ultimately reducing the power of the photovoltaic module. Summary of the invention

[0004] The embodiments of the present disclosure provide a solar cell and a method for preparing the same, so as to improve the photoelectric conversion efficiency of a solar cell including a sliced ​​cell, while significantly reducing mechanical damage to the sliced ​​cell, thereby significantly reducing the possibility of hidden cracks in a photovoltaic module including the sliced ​​cell, thereby improving product yield.

[0005] According to some embodiments of the present disclosure, on one hand, a method for preparing a solar cell is provided, comprising:

[0006] Providing a whole solar cell; wherein the whole solar cell includes a region to be divided;

[0007] Using a first laser device to form positioning grooves at two ends of the area to be segmented;

[0008] Using a second laser device to heat the area to be segmented starting from the positioning groove until the other positioning groove ends;

[0009] A spray device is used to spray cooling liquid onto the heated area to be split, so that the whole solar cell is split along a first direction in the area to be split to form at least two split cells; wherein the cooling liquid includes an oxidizing substance, the first direction intersects with a second direction, the second direction is the thickness direction of the split cell, the split cell includes a sub-front side and a sub-back side arranged oppositely along the second direction, and a cross section formed by the whole solar cell being split along the first direction, two complementary angles are formed between the cross section and the plane where the sub-back side is located, one of the angles is an acute angle, the whole solar cell has a front side and a back side arranged oppositely along the second direction, the sub-front side of at least two split cells formed based on the same whole solar cell is a partial area of ​​the front side, and the sub-back side of at least two split cells formed based on the same whole solar cell is a partial area of ​​the back side; the cross section is a silicon surface after surface hydroxylation;

[0010] A passivation layer is formed on the cross section.

[0011] According to some embodiments of the present disclosure, the oxidizing substance includes H2O2 or O3.

[0012] According to some embodiments of the present disclosure, the concentration of the oxidizing substance in the cooling liquid is in a range of 0.5%-50%.

[0013] According to some embodiments of the present disclosure, the spraying device includes a nozzle;

[0014] In the step of spraying cooling liquid onto the heated area to be segmented by using a spray 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.

[0015] According to some embodiments of the present disclosure, the laser temperature of the second laser device is in the range of 150°C-250°C.

[0016] According to some embodiments of the present disclosure, another aspect of the present disclosure further provides a solar cell, including:

[0017] Slice cells, at least two of which are formed by segmenting the same whole solar cell along a first direction, the whole solar cell having a front side and a back side arranged opposite to each other along a second direction, the slice cell having a sub-front side and a sub-back side arranged opposite to each other along the second direction, the sub-front side of at least two of the slice cells formed based on the same whole solar cell being a partial area of ​​the front side, and the sub-back side of at least two of the slice cells formed based on the same whole solar cell being a partial area of ​​the back side;

[0018] The second direction is the thickness direction of the split battery, and the first direction intersects with the second direction. The split battery has a cross section formed by the segmentation process, and two complementary angles are formed between the cross section and the plane where the sub-back surface is located, one of the angles is an acute angle, and the cross section is a silicon surface after surface hydroxylation;

[0019] The passivation layer is located on the cross section.

[0020] According to some embodiments of the present disclosure, the acute angle ranges from 45° to 80°.

[0021] According to some embodiments of the present 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, the second passivation layer contains a metal oxide material, the metal elements in the metal oxide material include at least one of Al element, Ti element, Zn element, Zr element, Hf element, Mo element, W element or Ni element, and the third direction is perpendicular to the cross-section.

[0022] According to some embodiments of the present disclosure, the passivation layer also includes an intermediate passivation layer, which is located between the first passivation layer and the second passivation layer, and both the intermediate passivation layer and the first passivation layer contain silicon elements, and the intermediate passivation layer and the second passivation layer contain the same metal element.

[0023] According to some embodiments of the present disclosure, the material of the intermediate passivation layer includes an oxide having the silicon element and the metal element.

[0024] The disclosed embodiment provides a solar cell and a method for preparing the same. On the one hand, since the preparation method is based on the principle of thermal stress battery separation, the whole solar cell can be segmented without ablating the area to be cut, which effectively reduces the mechanical damage to the segmented cells, thereby greatly reducing the possibility of hidden cracks in the photovoltaic module including the segmented cells, thereby improving the product yield. On the other hand, in the preparation method, a coolant including an oxidizing substance is used to cool the heated area to be segmented, so that the cross section of the segmented cells formed after the whole solar cell is split in the area to be segmented along a first direction is a silicon surface after surface hydroxylation, which can neutralize the 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 silicon surface and the passivation layer will be more continuous in structure, and the passivation improvement effect will be better. On the other hand, through the preparation method, the whole solar cell is split along the first direction in the area to be split, and the first direction intersects with the second direction, and the second direction is the thickness direction of the sliced ​​cell, that is, the whole solar cell is beveled to form a sliced ​​cell. The atomic arrangement density on the inclined cross-section formed on the sliced ​​cell is smaller, and the covalent bond surface density is smaller. The connection between adjacent atoms on the cross-section is not firm, which is more conducive to promoting the passivation layer on the cross-section to bond with the dangling bonds on the cross-section, thereby helping to further improve the passivation effect of the passivation layer on the cross-section, so as to further reduce the probability of carrier recombination on the cross-section, and increase the carrier life, thereby further improving the photoelectric conversion efficiency of the sliced ​​cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings, and these exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of a process for preparing a solar cell provided in an embodiment of the present disclosure;

[0027] Figure 2 A schematic cross-sectional structure diagram of a single whole solar cell provided in an embodiment of the present disclosure being divided into at least two sub-cells;

[0028] Figure 3 A schematic diagram of a top view structure in which a single whole solar cell provided in an embodiment of the present disclosure is divided into two sub-cells;

[0029] Figure 4 A schematic diagram of a top view structure in which a single whole solar cell provided in an embodiment of the present disclosure is divided into four sub-cells;

[0030] Figure 5 A schematic diagram of a top view structure of a single whole solar cell provided in an embodiment of the present disclosure being divided into 9 sub-cells;

[0031] Figure 6 A schematic diagram of a cross-section structure provided for an embodiment of the present disclosure;

[0032] Figure 7 For Figure 6 A schematic diagram of the structure of the passivation layer formed on the cross section shown;

[0033] Figure 8 A top view of a whole solar cell with positioning grooves provided in an embodiment of the present disclosure;

[0034] Fig. 9 A schematic diagram of the movement trajectory of the second laser device provided in an embodiment of the present disclosure;

[0035] Fig.10 A schematic diagram of a partial cross-sectional structure of a solar cell provided in an embodiment of the present disclosure;

[0036] Fig.11 A schematic diagram of the positional relationship between the nozzle and the second laser device provided in an embodiment of the present disclosure;

[0037] Figure 12-14 Three partial cross-sectional structural schematic diagrams of solar cells provided in the embodiments of the present disclosure;

[0038] Fig.15 for Fig.14 The graph showing the percentage of element contents in the sliced ​​battery and the passivation layer;

[0039] Fig.16 and Fig.17 Two other partial cross-sectional structural schematic diagrams of the solar cell provided in the embodiments of the present disclosure;

[0040] Fig.18 A schematic diagram of a partial three-dimensional structure of a photovoltaic assembly provided in an embodiment of the present disclosure;

[0041] Fig.19 for Fig.18 Schematic diagram of a cross-sectional structure along the cross-sectional direction NN1. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the technical solutions of the present disclosure will be clearly and completely described below in combination with the specific embodiments of the present disclosure and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0043] In the description of the embodiments of the present disclosure, "at least one" means one or more, "multiple" means two or more, and "multiple pieces" means two or more, unless otherwise clearly and specifically defined.

[0044] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0045] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0047] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0048] In the accompanying drawings corresponding to the embodiments of the present application, the thickness and area of ​​the layer are magnified for better understanding and ease of description. When describing a component (such as a layer, film, region or substrate) on another component or on the surface of another component, the component can be "directly" located on the surface of the other component, or a third component can be present between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0049] In the description of the embodiments of the present application, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, a film, a region, or a plate is referred to as being "on / located on" another component, it may 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 exist in between. In addition, when a component such as a layer, a film, a region, a plate, etc. is "directly located on" another component, or when a component such as a layer, a film, a region, a plate, etc. is located on the surface of another component, it means that no other components are located in between.

[0050] The present disclosure provides a method for preparing a solar cell. Figure 1 As shown, including:

[0051] S1. Provide a whole solar cell; wherein the whole solar cell includes a region to be divided.

[0052] The type of the whole solar cell is not limited. For example, the whole solar cell may include but is not limited to PERC cells (Passivated Emitter Rear Cell), IBC (Interdigitated Back Contact), TOPCon cells (Tunnel Oxide Passivated Contact), HIT / HJT cells (Heterojunction Technology), solar thin film cells or stacked cells, or any combination thereof. Among them, solar thin film cells include but are not limited to perovskite solar thin film cells, copper indium selenide solar thin film cells, gallium arsenide solar thin film cells or cadmium sulfide solar thin film cells. Stacked cells include but are not limited to perovskite cells superimposed on crystalline silicon cells, perovskite cells superimposed on perovskite cells or perovskite cells superimposed on thin film cells. Based on different cell types, the preparation method of the whole solar cell can be obtained according to relevant technologies, which will not be repeated here.

[0053] refer to Figure 3 As shown, the whole solar cell 100 can be divided into two sub-cells 110; or, referring to Figure 3 As shown, the whole solar cell 100 can be divided into four sub-cells 110; or, referring to Figure 5 As shown, the whole solar cell 100 can be divided into 9 sub-cells 110. Of course, the whole solar cell can also be divided into other numbers of sub-cells, which is not limited here. The position and number of the areas to be divided are determined according to the number of sub-cells of the whole solar cell.

[0054] S2. Use a first laser device to form positioning grooves at both ends of the area to be divided.

[0055] 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. The wavelength of the laser light is in the range of [200 nm, 2000 nm]. For example, the wavelength of the laser light may be 248 nm, 355 nmn, 375 nmn, 405 nm, 450 nm, 457 nm, 532 nm, 808 nm, 980 nm, 1064 nm, 1310 nm or 1550 nm, etc. According to the wavelength of the emitted laser light, the first laser may be an infrared laser, a visible light laser or an ultraviolet laser, etc. The power range of the first laser can be [20 W, 500 W]. For example, the power of the first laser can be 20 W, 40 W, 60 W, 80 W, 100 W, 150 W, 180 W, 200 W, 250 W, 280 W, 300 W, 350 W, 380 W, 400 W, 450 W, 480 W or 500 W, etc.

[0056] The positioning groove only needs to be set at both ends of the area to be segmented, and there is no need to form a whole cutting groove connecting the two ends of the area to be segmented as in the conventional laser cutting process; therefore, the positioning groove formed in the embodiment of the present disclosure is very small in size compared to the cutting groove formed by the conventional laser cutting process. The specific size of the positioning groove (for example, groove depth, groove width and groove length) can be selected according to actual requirements and is not limited here.

[0057] S3, using a second laser device to heat the area to be segmented starting from the positioning groove until the other positioning groove ends.

[0058] 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. The wavelength of the laser light is in the range of [200 nm, 2000 nm]. For example, the wavelength of the laser light may be 248 nm, 355 nmn, 375 nmn, 405 nm, 450 nm, 457 nm, 532 nm, 808 nm, 980 nm, 1064 nm, 1310 nm or 1550 nm. According to the wavelength of the emitted laser light, the second laser may be an infrared laser, a visible light laser or an ultraviolet laser. The power range of the second laser can be [20 W, 500 W]. For example, the power of the second laser can be 20 W, 40 W, 60 W, 80 W, 100 W, 150 W, 180 W, 200 W, 250 W, 280 W, 300 W, 350 W, 380 W, 400 W, 450 W, 480 W or 500 W, etc.

[0059] In the disclosed embodiment, the second laser and the first laser can be the same type of laser, for example, both are infrared lasers, visible light lasers or ultraviolet lasers, etc. Alternatively, the second laser and the first laser are different types of lasers, for example, the first laser is an infrared laser and the second laser is a visible light laser. In addition, the power of the second laser and the first laser can be the same or different, which is not limited here.

[0060] S4, using a spray device to spray cooling liquid to the heated area to be segmented, so that Figure 2 The whole solar cell 100 shown is split along the first direction X in the area to be split to form at least two split cells 110; wherein the cooling liquid includes an oxidizing substance, the first direction X intersects with the second direction Y, the second direction Y is the thickness direction of the split cell, the split cell 110 includes a sub-front side 110a and a sub-back side 110b arranged opposite to each other along the second direction Y, and a cross section 110c formed by the whole solar cell 100 being split along the first direction X, and two complementary angles β and γ are formed between the plane where the cross section 110c and the sub-back side 110b are located, one of which is an acute angle ( Figure 2 As shown in γ), reference Figure 2 As shown, the whole solar cell 100 has a front side 100a and a back side 100b arranged opposite to each other along the second direction Y, the sub-front side 110a of at least two sub-cells 110 formed based on the same whole solar cell is a partial area of ​​the front side 100a, and the sub-back side 110b of at least two sub-cells formed based on the same whole solar cell is a partial area of ​​the back side 100b; the cross section is Figure 6 The silicon surface shown is after surface hydroxylation.

[0061] The specific structure of the above-mentioned injection device is not limited, as long as it can achieve the corresponding function.

[0062] In the disclosed embodiment, steps S2-S4 are based on the principle of thermal stress battery separation to achieve lossless segmentation of the entire solar cell. The principle of thermal stress battery separation is as follows: first use a laser to quickly heat the material locally, and then use a matching cooling technology to cool the heated area, thereby generating an uneven temperature field. This temperature field will produce a temperature gradient on the surface of the material, thereby inducing the generation of thermal stress. The laser spot is in a compressive stress state, while the laser spot is in a tensile stress state before and after. Since the compressive stiffness of the brittle material is much greater than the tensile strength, when the tensile stress reaches the fracture strength of the material, the material will break. The fracture will start from the notch at the edge of the battery cell and expand steadily along the moving track of the laser and subsequent cooling.

[0063] Take the example of a whole solar cell being divided into two sub-cells. Figure 8As shown, the whole solar cell 100 can be divided into two sub-cells 110, and positioning grooves 1 are formed at both ends of the area A to be divided. Fig. 9 As shown, when the laser generated by the second laser device starts to heat the area to be segmented A from the positioning groove, its moving trajectory is shown by the black thick line 2, and the spray device follows the second laser device to spray cooling liquid on the heated area to be segmented. Based on the above battery separation principle, reference Figure 2 As shown, the whole solar cell is split along the first direction X in the area to be split to form two split cells 110. Of course, if the whole solar cell is split into more than two split cells, the above steps S2-S4 need to be performed on different areas to be split in the whole solar cell to obtain more than two split cells.

[0064] In the embodiment of the present disclosure, in step S4, a cooling liquid including an oxidizing substance is used to cool the heated area to be segmented. In this way, the cross section of the segmented cell formed after the entire solar cell is split along the first direction in the area to be segmented is as follows: Figure 6 The silicon surface after surface hydroxylation shown in the figure is shown in the figure. Figure 6 As shown, hydrogen-oxygen bonds are formed on the silicon surface of the split cell, which can neutralize the dangling bonds and provide protection for the exposed silicon at the cross section; in addition, Figure 7 As shown, when a passivation layer 101 is subsequently formed on the cross section, since the passivation layer is mostly made of oxide material, the silicon surface after surface hydroxylation (ie, cross section 110c) and the passivation layer 101 will be more continuous in structure, and the passivation improvement effect will be better.

[0065] It should be noted that the embodiment of the present disclosure can control the size of the laser spot emitted by the second laser device so that the entire solar cell is split along the first direction in the area to be split, the first direction intersects with the second direction, and the second direction is the thickness direction of the split cell, that is, reference Figure 2 As shown, the whole solar cell 100 is beveled to form a sliced ​​cell 110. For the sub-front side 110a and the sub-back side 110b on the sliced ​​cell 110, the cross section on the sliced ​​cell 110 can be regarded as an inclined surface.

[0066] Compared with the related art in which the whole solar cell is divided along the thickness direction of the whole solar cell to form a cross section of the split cell, Fig.10As shown, in the embodiment of the present disclosure, the atomic arrangement density on the inclined section 110c formed on the split battery 110 is smaller, and the covalent bond surface density is smaller. The connection between adjacent atoms on the section 110c is not firm, which is more conducive to promoting the passivation layer 101 located on the section 110c to form bonds with the dangling bonds on the section 110c, that is, it is easier for the passivation layer 101 to saturate the dangling bonds on the section 110c. In addition, the passivation layer 101 can also passivate other surface defects on the section 110c, which is conducive to further improving the ability of the passivation layer 101 to reduce the defect state density of the section 110c, so as to further reduce the recombination center of the section 110c to reduce the probability of carrier recombination. In other words, designing the cross section 110c of the segmented cell 110 to be inclined rather than perpendicular to its sub-back side 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, increase the carrier lifespan, and thus further improve the photoelectric conversion efficiency of the segmented cell.

[0067] S5. Reference Fig.10 As shown, a passivation layer 101 is formed on the section 110c.

[0068] In the embodiments of the present disclosure, the passivation layer can be prepared by processes such as CVD (Chemical Vapor Deposition), PECVD (Plasma Enhanced Chemical Vapor Deposition), ALD (Atomic Layer Deposition) or PEALD (Plasma Enhanced Atomic Layer Deposition).

[0069] In the embodiments of the present disclosure, the number of layers, thickness, and material of the passivation layer are not limited. For example, along the third direction, the passivation layer includes at least a first passivation layer and a second passivation layer stacked, the first passivation layer includes a silicon oxide material, and the second passivation layer includes a metal oxide material, and the metal element in the metal oxide material includes at least one of Al (aluminum) element, Ti (titanium) element, Zn (zinc) element, Zr (zirconium) element, Hf (hafnium) element, Mo (molybdenum) element, W (tungsten) element or Ni (nickel) element, and the third direction is perpendicular to the cross section. Alternatively, the passivation layer also includes an intermediate passivation layer, which is located between the first passivation layer and the second passivation layer, and the intermediate passivation layer and the first passivation layer both include silicon element, and the intermediate passivation layer and the second passivation layer include the same metal element. The material of the intermediate passivation layer includes an oxide having silicon element and metal element. It should be noted that the relevant detailed structural description of the passivation layer can refer to the relevant description of the subsequent solar cell embodiment, which will not be repeated here.

[0070] In the embodiment of the present disclosure, a sliced ​​cell is formed through steps S1-S5. On the one hand, since the preparation method is based on the principle of thermal stress cell separation, the whole solar cell can be segmented without ablating the area to be cut, which effectively reduces the mechanical damage of the sliced ​​cell, thereby greatly reducing the possibility of hidden cracks in the photovoltaic module including the sliced ​​cell, thereby improving the product yield. On the other hand, in the preparation method, a coolant including an oxidizing substance is used to cool the heated area to be segmented, so that the cross section of the sliced ​​cell formed after the whole solar cell is split in the area to be segmented along the first direction is a silicon surface after surface hydroxylation, which can neutralize the 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 silicon surface and the passivation layer will be more continuous in structure, and the passivation improvement effect will be better. On the other hand, through the preparation method, the whole solar cell is split along the first direction in the area to be split, and the first direction intersects with the second direction, and the second direction is the thickness direction of the sliced ​​cell, that is, the whole solar cell is beveled to form a sliced ​​cell. The atomic arrangement density on the inclined cross-section formed on the sliced ​​cell is smaller, and the covalent bond surface density is smaller. The connection between adjacent atoms on the cross-section is not firm, which is more conducive to promoting the passivation layer on the cross-section to bond with the dangling bonds on the cross-section, thereby helping to further improve the passivation effect of the passivation layer on the cross-section, so as to further reduce the probability of carrier recombination on the cross-section, and increase the carrier life, thereby further improving the photoelectric conversion efficiency of the sliced ​​cell.

[0071] In one or more embodiments, in order to improve the oxidizing property, the oxidizing substance includes H2O2 or O3. The cooling liquid can be deionized water including H2O2 or O3, or other liquids including H2O2 or O3.

[0072] In one or more embodiments, the concentration of the oxidizing substance in the cooling liquid ranges from 0.5% to 50%. For example, the concentration of the oxidizing substance (e.g., H2O2 or O3) can 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%.

[0073] In one or more embodiments, the spraying device includes a nozzle; in step S3, using the spraying device to spray the cooling liquid to the heated area to be segmented, reference Fig.11 As shown, the distance d between the projection of the nozzle 3 on the area to be segmented A and the laser spot formed by the second laser device 4 on the area to be segmented along the laser scanning direction M is in the range of 1-10mm, and the distance can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm. If the distance is too large, the area to be segmented cannot be cooled quickly after heating, thereby affecting the generation of thermal stress; if the distance is too small, it will affect the heating effect of the area to be segmented. Therefore, it is necessary to select a suitable distance to take into account both requirements.

[0074] In one or more embodiments, the laser temperature of the second laser device is in the range of 150° C.-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 with the laser spot temperature in the conventional laser cutting process which can reach 400° C.-500° C., the preparation method provided by the embodiment of the present disclosure has low processing temperature and low production cost.

[0075] The present disclosure also provides a solar cell, referring to Figure 2 and Fig.10, solar cells include: segmented solar The at least two split cells 110 are formed by splitting the same whole solar cell 100 along the first direction X, the whole solar cell 100 has a front side 100a and a back side 100b arranged relatively along the second direction Y, the split cell 110 has a sub-front side 110a and a sub-back side 110b arranged relatively along the second direction Y, the sub-front side 110a of the at least two split cells 110 formed based on the same whole solar cell 100 is a partial area of ​​the front side 100a, and the sub-back side 110b of the at least two split cells 110 formed based on the same whole solar cell 100 is a partial area of ​​the back side 100b; wherein the second direction Y is the thickness direction of the split cell 110, and the first direction X intersects with the second direction Y, the split cell 110 has a cross section 110c formed by the splitting process, and two complementary angles are formed between the cross section 110c and the plane where the sub-back side 110b is located, one of the angles is an acute angle, and the cross section 110c is Figure 6 The silicon surface after surface hydroxylation is shown; the passivation layer 101 is located at least on the section 110c.

[0076] It should be noted that the solar cell can be formed by any of the aforementioned solar cell preparation methods, or can be formed by other preparation methods, which are not limited here.

[0077] In the solar cell provided in the embodiment of the present disclosure, the cross section of the split cell is as follows Figure 6 The silicon surface after surface hydroxylation shown in the figure is shown in the figure. Figure 6 As shown, hydrogen-oxygen bonds are formed on the silicon surface of the split cell, which can neutralize the dangling bonds and provide protection for the exposed silicon at the cross section; in addition, 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 material, 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.

[0078] In the solar cell provided in the embodiment of the present disclosure, reference Figure 2 As shown, at least two slice cells 110 are formed by segmenting the same whole solar cell 100 along the first direction X, the first direction intersects with the second direction, the second direction is the thickness direction of the slice cell, that is, the whole solar cell 100 is beveled to form the slice cell 110, and for the sub-front side 110a and the sub-back side 110b on the slice cell 110, the cross section on the slice cell 110 can be regarded as an inclined surface.

[0079] Compared with the related art in which the whole solar cell is divided along the thickness direction of the whole solar cell to form a cross section of the split cell, Fig.10 As shown, in the embodiment of the present disclosure, the atomic arrangement density on the inclined section 110c formed on the split battery 110 is smaller, and the covalent bond surface density is smaller. The connection between adjacent atoms on the section 110c is not firm, which is more conducive to promoting the passivation layer 101 located on the section 110c to form bonds with the dangling bonds on the section 110c, that is, it is easier for the passivation layer 101 to saturate the dangling bonds on the section 110c. In addition, the passivation layer 101 can also passivate other surface defects on the section 110c, which is conducive to further improving the ability of the passivation layer 101 to reduce the defect state density of the section 110c, so as to further reduce the recombination center of the section 110c to reduce the probability of carrier recombination. In other words, designing the cross section 110c of the segmented cell 110 to be inclined rather than perpendicular to its sub-back side 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, increase the carrier lifespan, and thus further improve the photoelectric conversion efficiency of the segmented cell.

[0080] In the embodiments of the present disclosure, on the one hand, the cross section of the sliced ​​cell is a silicon surface after surface hydroxylation, which can neutralize the 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 silicon surface after surface hydroxylation and the passivation layer will be more continuous in structure, and the passivation improvement effect will be better. On the other hand, at least two sliced ​​cells are formed by segmenting the same whole solar cell along a first direction, the first direction intersects with the second direction, and the second direction is the thickness direction of the sliced ​​cell, that is, the whole solar cell is beveled to form the sliced ​​cell. The atomic arrangement density on the inclined cross section formed on the sliced ​​cell is smaller, and the covalent bond surface density is smaller. The connection between adjacent atoms on the cross section is not firm, which is more conducive to promoting the passivation layer on the cross section to bond with the dangling bonds on the cross section, thereby helping to further improve the passivation effect of the passivation layer on the cross section, so as to further reduce the probability of carrier recombination on the cross section, increase the carrier life, and further improve the photoelectric conversion efficiency of the sliced ​​cell.

[0081] In some cases, reference Figure 3 As shown, the corners connected in sequence on the four sides of the whole solar cell 100 are rounded corners 100c. Based on this, the corners connected in sequence on the side 110d of the sliced ​​cell 110 that has not been split are still rounded corners 100c, but the corners of the section 110c connected to the side 110d in the sliced ​​cell 110 do not have rounded corners.

[0082] In some cases, combined Figure 2 and Figure 3As shown, in two sub-cells 110 belonging to the same whole solar cell 100, the angle between the cross section 110c of one sub-cell 110 and its sub-back surface 110b is a first angle β, and the angle between the cross section 110c of the other sub-cell 110 and its sub-back surface 110b is a second angle γ, and the first angle β and the second angle γ are complementary. It should be noted that, Figure 2 In the example, the first angle β is an obtuse angle and the second angle γ is an acute angle.

[0083] In other examples, reference Figure 4 As shown, a single sliced ​​cell 110 is 1 / 4 of the entire solar cell 100 .

[0084] In some cases, reference Figure 4 As shown, the segmentation path in the whole solar cell 100 is in the shape of a cross, and a rounded corner 100c is reserved at one corner of any segmented cell 110. Moreover, among the four segmented cells 110 belonging to the same whole solar cell 100, any segmented cell 110 has two cross sections 110c.

[0085] In one example, refer to Figure 4 As shown, among the two sections 110c of the same split battery 110, the angle between one section 110c and the sub-back surface 110b of the split battery 110 is a third angle (not shown in the figure), and the angle between the other section 110c and the split battery 110 is a fourth angle (not shown in the figure), and the third angle and the fourth angle are both acute angles; in another example, referring to Figure 4 As shown, among the two sections 110c of the same split battery 110, the angle between one section 110c and the sub-back surface 110b of the split battery 110 is a third angle (not shown in the figure), and the angle between the other section 110c and the split battery 110 is a fourth angle (not shown in the figure), and the third angle and the fourth angle are both obtuse angles; in another example, referring to Figure 4 As shown, among the two sections 110c of the same slice battery 110, the angle between one section 110c and the sub-back side 110b of the slice battery 110 is the third angle (not shown in the figure), and the angle between the other section 110c and the slice battery 110 is the fourth angle (not shown in the figure), and one of the third angle and the fourth angle is an acute angle, and the other is an obtuse angle.

[0086] It should be noted that there are multiple possibilities for the first direction X intersecting with the second direction Y. Based on different choices of the first direction X, the two sections 110c of the same split battery 110 may present different tilt states, which can be flexibly designed according to requirements in actual applications.

[0087] In other cases, the whole solar cell can also be divided into four slice cells in sequence along a fixed direction, and then only two slice cells each have two rounded corners. Among the four slice cells belonging to the same whole solar cell, the two slice cells with rounded corners each have only one cross section, and the remaining two slice cells each have two opposite cross sections along the fixed direction.

[0088] It should be noted that, based on the different ways of dividing the whole solar cell 100, among at least two slice cells 110 belonging to the same whole solar cell 100, the number of cross-sections 110c possessed by different slice cells 110 and the inclination state of each cross-section 110c may be different, and can be flexibly designed according to needs in actual applications.

[0089] In some other examples, reference Figure 5 As shown, a single sliced ​​cell 110 is 1 / 9 of the entire solar cell 100 .

[0090] It should be noted that the above Figures 3 to 5 The three examples shown are all examples of a whole solar cell 100 being divided into at least two sub-cells 110. In practical applications, the number N of sub-cells 110 divided by a single whole solar cell 100 can be adjusted according to needs and size, for example, N can also be 3, 5, 6, 7, 8 or 10. In addition, an embodiment of the present disclosure does not limit the division path of the whole solar cell 100, which can be flexibly adjusted according to needs.

[0091] In the above various embodiments, reference Figures 2 to 5 ,as well as Fig.10 As shown, in a partial number of split batteries 110, the area of ​​the sub-front side 110a may be larger than the area of ​​the sub-back side 110b, and a first angle β is formed between at least one section 110c and the sub-back side 110b, and the supplementary angle of the first angle β is an acute angle, that is, the first angle β formed between the section 110c and the sub-back side 110b is an obtuse angle, and an acute angle is also formed between the section 110c and the plane where the sub-back side 110b is located.

[0092] In the above various embodiments, reference Figures 2 to 5 ,as well as Fig.10 As shown, in another portion of the split battery cells 110, the area of ​​the sub-front side 110a may be smaller than the area of ​​the sub-back side 110b, and a second angle γ is formed between at least one section 110c and the sub-back side 110b, the second angle γ is an acute angle, and an obtuse angle is also formed between the section 110c and the plane where the sub-back side 110b is located.

[0093] It should be noted that, in actual applications, for a split battery with at least two cross-sections, the angles between a certain number of cross-sections and their sub-back sides are acute angles, while the angles between another number of cross-sections and their sub-back sides are obtuse angles. In this case, the area of ​​the sub-front side of the split battery may be equal to the area of ​​its sub-back side.

[0094] It is worth noting that in the above various embodiments, reference Figures 2 to 5 ,as well as Fig.10 As shown, for any cross section 110c, the angle formed between the cross section 110c and the corresponding sub-rear surface 110b is an acute angle or an obtuse angle.

[0095] In the above various embodiments, reference Figures 3 to 5 The shape of the orthographic projection of the split battery 110 on the sub-back surface 110 b may be a rectangle, and some corners of the rectangle are rounded 100 c.

[0096] In one or more embodiments, the acute angle ranges from 45° to 80°. For example, the specific angle of the acute angle may be 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°. 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 side 110b is too large, and the portion of the slice battery 110 including the cross section 110c can be regarded as a tip protruding from the entire slice battery 110. The smaller the acute angle, the more protruding the tip, and the easier it is for the tip to break when under pressure, which is not conducive to improving the structural stability of the slice battery 110; if the acute angle is greater than 80°, the inclination of the cross section 110c relative to the sub-back side 110b is too small, which is not conducive to reducing the atomic arrangement density on the cross section 110c, and is therefore not conducive to improving the passivation effect of the passivation layer 101 on the cross section 110c. Therefore, the acute angle is designed to be 45°-80°, and the inclination of the cross section 110c relative to the sub-back side 110b is controlled, which is beneficial to improving the structural stability of the slice battery 110 and reducing the probability of damage to the slice battery 110, while effectively reducing the atomic arrangement density on the cross section 110c, thereby enhancing the passivation effect of the passivation layer 101 on the cross section 110c.

[0097] In one or more embodiments, reference Fig.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 which are stacked, the first passivation layer 111 includes a silicon oxide material, the second passivation layer 121 includes a metal oxide material, the metal elements in the metal oxide material include at least one of Al (aluminum) element, Ti (titanium) element, Zn (zinc) element, Zr (zirconium) element, Hf (hafnium) element, Mo (molybdenum) element, W (tungsten) element or Ni (nickel) element, and the third direction Z is perpendicular to the section 110c.

[0098] So, reference Fig.12 As shown, on the one hand, the first passivation layer 111 is designed to include a silicon oxide material, and the cross section 110c is chemically passivated by the silicon oxide material. For example, the oxygen atoms in the first passivation layer 111 and the cross section 110c are saturated with dangling bonds, and the ability of the oxygen atoms to saturate the dangling bonds on the cross section 110c is enhanced by means of the cross section 110c tilted relative to the sub-back surface 110b, so as to further 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 probability of carrier recombination; on the other hand, the second passivation layer 121 is designed to include a metal oxide material, and the metal elements in the metal oxide material include Al elements, T At least one of the i element, Zn element, Zr element, Hf element, Mo element, W element or Ni element, with the help of the metal element in the second passivation layer 121, the second passivation layer 121 itself has a high density of fixed charges, and the high density of fixed charges can generate a large electric field, thereby performing good field effect passivation on the section 110c, for example, a large energy band bending is generated between the second passivation layer 121 and the section 110c, hindering the minority carriers from migrating to the section 110c, reducing the concentration of minority carriers at the section 110c, thereby helping to reduce the probability of recombination of majority carriers and minority carriers at the section 110c. In this way, the first passivation layer 111 and the second passivation layer 121 cooperate together, and cooperate with the section 110c inclined relative to the sub-back surface 110b, which is conducive to significantly improving the photoelectric conversion efficiency of the sliced ​​cell 110, thereby improving the photoelectric conversion efficiency of the solar cell.

[0099] In addition, reference Fig.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, so that the film stability of the first passivation layer 111 is high, which 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.

[0100] Moreover, silicon oxide material also has a good anti-PID (potential induced degradation) effect. Since the subsequent packaging materials of photovoltaic modules formed based on solar cells are difficult to achieve 100% isolation from the outside world, water vapor may enter the interior of the solar cell through the packaging materials or backplane used for edge sealing in a humid environment. At this time, the glass in the packaging material will produce sodium ions, and the sodium ions will move to the surface of the solar cell under the action of the external electric field to produce PID phenomenon, resulting in a decrease in the photoelectric conversion efficiency of the solar cell. The silicon oxide material has good compactness and insulation, so it has a good effect on preventing water vapor from entering the cross section to enter the sliced ​​cell, thereby having a good anti-PID effect. In this way, even if the packaging material of the photovoltaic module is difficult to achieve complete insulation, water vapor enters the environment of the solar cell through the packaging material used for edge sealing, and the film layer composed of the silicon oxide material can also prevent the sodium ions in the glass in the packaging material from moving to the cross section 110c, thereby preventing the PID phenomenon and maintaining a high photoelectric conversion rate of the solar cell.

[0101] In some cases, along a direction perpendicular to the first direction X, i.e., direction Z, the first passivation layer 111 and the second passivation layer 121 are stacked on the cross section 110c. Compared with the second passivation layer 121, the first passivation layer 111 is closer to the cross section 110c. For example, the first passivation layer 111 can cover the cross section 110c. This helps shorten the migration path of oxygen atoms in the first passivation layer 111 to the surface defects on the section 110c, so as to improve the chemical passivation effect of oxygen atoms in the first passivation layer 111 on the section 110c; moreover, compared with the second passivation layer 121 comprising metal oxide material, the lattice of the first passivation layer 111 comprising silicon oxide material is more adapted to the lattice of the substrate in the slice battery 110, which helps to avoid the problem of large lattice mismatch between the section 110c and the second passivation layer 121 when the section 110c is in direct contact with the second passivation layer 121, so as to avoid the problem of increased surface defects caused by lattice mismatch, thereby improving the interface passivation effect on the section 110c.

[0102] The metal oxide material included in the second passivation layer is exemplified below.

[0103] In some examples, reference Fig.12As shown, the metal element in the metal oxide material includes Al element, that is, the second passivation layer 121 includes aluminum oxide material. On the one hand, the aluminum oxide material enables the second passivation layer 121 to have a high density of fixed negative charges (Qf is approximately 1012cm-2-1013cm-2), which is beneficial to improving the field passivation effect of the second passivation layer 121 on the section 110c, so as to reduce the probability of carrier recombination at the section 110c, thereby helping to improve the photoelectric conversion efficiency of the slice battery 110; on the other hand, in the technology of forming the second passivation layer 121 containing aluminum oxide material, the second passivation layer 121 will also have an appropriate amount of hydrogen ions, so that the second passivation layer 121 has a good hydrogen passivation effect on the section 110c. For example, the appropriate amount of hydrogen ions in the second passivation layer 121 can not only effectively saturate the dangling bonds on the section 110c through migration, but also inhibit the recombination of itself with carriers, which is beneficial to ensure that the carriers are effectively converged to the corresponding electrodes in the slice battery 110, so as to further improve the photoelectric conversion efficiency of the slice battery 110.

[0104] In other examples, reference Fig.12 As shown, the metal element in the metal oxide material includes the Mo element, that is, the second passivation layer 121 includes a molybdenum oxide material. On the one hand, the molybdenum oxide material enables the second passivation layer 121 to have a high work function, which is also conducive to the second passivation layer 121 having a good field passivation effect on the cross section 110c; on the other hand, in the technology of forming the second passivation layer 121 including the molybdenum oxide material, the second passivation layer 121 also has a proper amount of hydrogen ions, so that the second passivation layer 121 has a good hydrogen passivation effect on the cross section 110c.

[0105] It should be noted that the above two examples are examples of the metal oxide material in the second passivation layer having a good passivation effect on the cross section. In practical applications, the metal element in the metal oxide material includes at least one of the Al element, the Ti element, the Zn element, the Zr element or the Hf element, which can make the second passivation layer have a high density of fixed negative charge to perform a good field passivation effect on the cross section; the metal element in the metal oxide material includes at least one of the Mo element, the W element or the Ni element, which can make the second passivation layer have a high density of fixed positive charge or a high work function to perform a good field passivation effect on the cross section 110c.

[0106] In one or more embodiments, reference Fig.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, and both the intermediate passivation layer 131 and the first passivation layer 111 contain silicon elements, and the intermediate passivation layer 131 and the second passivation layer 121 contain the same metal elements.

[0107] It is worth noting that reference Fig.13 As shown, the intermediate passivation layer 131 not only has the same element as the first passivation layer 111, namely, silicon, but also has the same element as the second passivation layer 121, namely, metal. In this way, the intermediate passivation layer 131 is not only conducive to making the lattice at the interface where the intermediate passivation layer 131 and the first passivation layer 111 are in contact more compatible with the silicon element, but also conducive to making the lattice at the interface where the intermediate passivation layer 131 and the second passivation layer 121 are in contact more compatible with the metal element, which is conducive to avoiding the problem of large lattice mismatch between the first passivation layer 111 and the second passivation layer 121 when the first passivation layer 111 and the second passivation layer 121 are in direct contact, so as to avoid the problem of increased surface defects caused by lattice mismatch, thereby improving the interface passivation effect of the passivation layer 101 on the split battery 110, for example, improving the passivation effect on the cross section 110c.

[0108] In other words, reference Fig.13 As shown, the intermediate passivation layer 131 plays a transition role to improve the adaptability of the lattice at the interface where the first passivation layer 111, the intermediate passivation layer 131 and the second passivation layer 121 contact each other in sequence, and prevent the occurrence of gaps and dislocation phenomena at the interface where the first passivation layer 111, the intermediate passivation layer 131 and the second passivation layer 121 contact each other in sequence, so as to improve the uniformity of the film layer of the passivation layer 101 itself, thereby improving the interface passivation effect of the passivation layer 101 on the slice battery 110. Moreover, it is beneficial to improve the connection strength between the first passivation layer 111 and the intermediate passivation layer 131, and the connection strength between the intermediate passivation layer 131 and the second passivation layer 121 by means of the intermediate passivation layer 131, so as to avoid the mutual slippage or shedding problem between the first passivation layer 111 and the intermediate passivation layer 131, or the intermediate passivation layer 131 and the second passivation layer 121, thereby helping to improve the structural stability of the passivation layer 101. In this way, it can be ensured that the intermediate passivation layer 131 not only has the same elements as the first passivation layer 111, but also has the same elements as 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, and the oxygen atoms in the intermediate passivation layer 131 can be utilized based on the migration of these oxygen atoms toward the cross section 110c to further saturate the dangling bonds on the cross section 110c, so as to further reduce the defect state density of the cross section 110c, thereby further reducing the recombination center of the cross section 110c to reduce the probability of carrier recombination.

[0109] In some embodiments, in combination Fig.14 and Fig.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 that at the second surface f, and the content of metal element at the first surface e is lower than that at the second surface f.

[0110] Combination Fig.14 and Fig.15 As shown, on the one hand, the first passivation layer 111 contains silicon oxide material. Based on this, the content of silicon element at the first surface e where the intermediate passivation layer 131 contacts the first passivation layer 111 is designed to be higher than that at the second surface f. Compared with the second surface f, it is beneficial to enrich the silicon element at the first surface e, thereby helping to further improve the adaptability of the lattice at the interface where the intermediate passivation layer 131 and the first passivation layer 111 contact by increasing the content of silicon element at the first surface e, further reducing the defect state density at the first surface e, thereby further improving 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 the metal element at the second surface f where the intermediate passivation layer 131 contacts the second passivation layer 121 is designed to be higher than the content at the first surface e, which is beneficial to enrich the metal element at the second surface f, thereby further improving the adaptability of the lattice at the interface where the intermediate passivation layer 131 and the second passivation layer 121 contact by increasing the content of the metal element at the second surface f, further reducing the defect state density at the second surface f, and further improving the passivation effect of the passivation layer 101 on the section 110c.

[0111] In some embodiments, in combination Fig.14 and Fig.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 tends to decrease, and the content of metal in the intermediate passivation layer 131 tends to increase. 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, the direction Z is perpendicular to the first direction X.

[0112] It is worth noting that the content of silicon at the first surface e is higher than that at the second surface f, and the content of metal at the first surface e is lower than that at the second surface f, which is conducive to ensuring that the content of silicon in the intermediate passivation layer 131 is decreasing and the content of metal in the intermediate passivation layer 131 is increasing in the direction from the first passivation layer 111 to the second passivation layer 121. In addition, both silicon and metal elements in the intermediate passivation layer 131 are changing in a trend, that is, gradually changing, which is conducive to improving the performance stability of the intermediate passivation layer 131 and avoiding performance mutations caused by sudden changes in the content of elements in the intermediate passivation layer 131.

[0113] In some embodiments, in combination Fig.14 and Fig.15 As shown, the intermediate passivation layer 131 may further include oxygen. In the direction Z from the first passivation layer 111 to the second passivation layer 121 , the content of oxygen in the intermediate passivation layer 131 first increases and then decreases.

[0114] It is worth noting that, in order to improve the adaptability of the lattice at the interface where the intermediate passivation layer 131 contacts the first passivation layer 111, and to improve the adaptability of the lattice at the interface where the intermediate passivation layer 131 contacts the second passivation layer 121, the first surface e where the intermediate passivation layer 131 contacts the first passivation layer 111 is designed to be enriched with silicon elements, and the second surface f where the intermediate passivation layer 131 contacts the second passivation layer 121 is designed to be enriched with metal elements, so that the peak value of the content of the oxygen element in the intermediate passivation layer 131 is located in the middle part in the direction from the first passivation layer 111 to the second passivation layer 121, so as to ensure that one of the two ends of the intermediate passivation layer 131 is rich in silicon elements and the other is rich in metal elements. Based on this, the content of the oxygen element in the intermediate passivation layer 131 is designed to increase first and then decrease, so as to ensure that the passivation layer 101 has a high passivation effect on the cross section 110c.

[0115] It should be noted that, in some embodiments, a parameter showing an increasing trend means that the parameter gradually increases, that is, during the change process, the parameter has been gradually increasing; a parameter showing a decreasing trend means that the parameter gradually decreases, that is, during the change process, the parameter has been gradually decreasing. In other embodiments, a parameter showing an increasing trend means that during the change process, the parameter is increasing as a whole, and in the local change process, the parameter may be gradually decreasing; a parameter showing a decreasing trend means that during the change process, the parameter is decreasing as a whole, and in the local change process, the parameter may be gradually increasing. In other embodiments, a parameter showing an increasing trend may mean that the parameter gradually increases, a parameter showing a decreasing trend may mean that the parameter is decreasing as a whole, and in the local change process, the parameter is gradually increasing; or, a parameter showing an increasing trend may mean that the parameter is increasing as a whole, and in the local change process, the parameter is gradually decreasing, and a parameter showing a decreasing trend means that the parameter is gradually decreasing. The above parameters include but are not limited to the content of silicon element in the middle passivation layer 131 , the content of metal element in the middle passivation layer 131 , and the content of oxygen element in the middle passivation layer 131 .

[0116] also, Fig.15 The above is only an example of the change trend of the content ratio of the silicon element, the metal element and the oxygen element in the partial area of ​​the slice battery 110 and the passivation layer 101 in the slice battery. In actual applications, the change trend of the content ratio of the silicon element, the metal element and the oxygen element in the slice battery 110 and the passivation layer 101 may also be partially or completely different from the above. Fig.15 The examples shown have differences. In one example Fig.15 The metal element may be aluminum.

[0117] In some embodiments, the material of the intermediate passivation layer 131 may be a common oxide of silicon and aluminum, and the material of the second passivation layer 121 may be an aluminum oxide material.

[0118] In some embodiments, reference Fig.14 As shown, in 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 middle passivation layer 131 , and the thickness D3 of the middle passivation layer 131 is less than the thickness D2 of the second passivation layer 121 .

[0119] refer to Fig.14As shown, the first passivation layer 111 includes silicon oxide material. When the thickness of the film layer including silicon oxide material along direction Z, i.e. D1, is small, it can ensure that the first passivation layer 111 has a good chemical passivation effect on the section 110c, and compared with forming a first passivation layer 111 with a large thickness, the formation process of the first passivation layer 111 with a small D1 is simpler; in addition, the thickness D1 of the first passivation layer 111 is small. When the intermediate passivation layer 131 contains oxygen elements, it is also beneficial to make the oxygen atoms in the intermediate passivation layer 131 easier to migrate to the section 110c, so as to further improve the chemical passivation effect on the section 110c.

[0120] refer to Fig.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 direction Z is appropriate, and it is best to facilitate the migration of oxygen atoms in the intermediate passivation layer 131 to the cross section 110c. In addition, the second passivation layer 121 includes a metal oxide material. Along the direction Z, within a certain thickness range, the greater the thickness of the film layer including 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 direction Z, the thickness D2 of the second passivation layer 121 is designed to be maximum, the thickness D1 of the first passivation layer 111 is designed to be minimum, and the thickness D3 of the intermediate passivation layer 131 is designed to be between D1 and D2. This can ensure that the first passivation layer 111 has a good chemical passivation effect on the cross section 110c, and that the second passivation layer 121 has a good field effect passivation effect on the cross section 110c, and is beneficial to the migration of oxygen atoms in the intermediate passivation layer 131 to the cross section 110c.

[0121] In some embodiments, reference Fig.14 As shown, the thickness D1 of the first passivation layer 111 may be 1 nm-10 nm along the direction Z. In some examples, the thickness D1 of the first passivation layer 111 may be 4 nm-7 nm, such as 4.5 nm, 5 nm, 5.5 nm, 6 nm or 6.5 nm.

[0122] In some embodiments, reference Fig.14 As shown, the thickness D2 of the second passivation layer 121 may be 20 nm-100 nm along the direction Z. In some examples, the thickness D2 of the second passivation layer 121 may be 40 nm-60 nm, such as 45 nm, 48 nm, 50 nm, 53 nm, 55 nm or 58 nm.

[0123] In some embodiments, reference Fig.14As shown, the thickness D3 of the intermediate passivation layer 131 may be 4nm-15nm along the direction Z. In some examples, the thickness D3 of the intermediate passivation layer 131 may be 8nm-12nm, such as 8.5nm, 9nm, 9.5nm, 10nm, 10.5nm, 11nm or 11.5nm.

[0124] In some embodiments, the intermediate passivation layer may further include oxygen element, and the silicon element content in the intermediate passivation layer is 2%-60%, the metal element content is 2%-50%, and the oxygen element content is 38%-50%.

[0125] It should be noted that the silicon content in the intermediate passivation layer is 2%-60%, which means: the average value of the silicon content in the intermediate passivation layer is in the range of 2%-60%, and the silicon content in different regions of the intermediate passivation layer may be within the average value or may not be within the average value. Similarly, the metal content in the intermediate passivation layer is 2%-50%, which means: the average value of the metal content in the intermediate passivation layer is in the range of 2%-50%, and the metal content in different regions of the intermediate passivation layer may be within the average value or may not be within the average value; the oxygen content in the intermediate passivation layer is 38%-50%, which means: the average value of the oxygen content in the intermediate passivation layer is in the range of 38%-50%, and the oxygen content in different regions of the intermediate passivation layer may be within the average value or may not be within the average value.

[0126] In some cases, reference Fig.14 As shown, for the area with the largest silicon content in the intermediate passivation layer 131, such as the first surface e, the silicon content in this area is 40%-80%, for example, the silicon content in this area can be 60%; for the area with the smallest silicon content in the intermediate passivation layer 131, such as the second surface f, the silicon content in this area is 2%-5%, for example, the silicon content in this area can be 3%.

[0127] In some cases, reference Fig.14 As shown, for the area with the smallest metal element content in the intermediate passivation layer 131, such as the first surface e, the metal element content in this area is 2%-5%, for example, the metal element content in this area can be 3%; for the area with the largest metal element content in the intermediate passivation layer 131, such as the second surface f, the metal element content in this area is 30%-70%, for example, the metal element content in this area can be 50%.

[0128] In some cases, reference Fig.14As shown, for the area with the largest oxygen content in the intermediate passivation layer 131, such as the middle area of ​​the intermediate passivation layer 131, the oxygen content in this area is 45%-60%, for example, the oxygen content in this area can be 60%; for the area with the smallest oxygen content in the intermediate passivation layer 131, such as the first surface e or the second surface f, the oxygen content in this area is 20%-40%, for example, the oxygen content in this area can be 20%.

[0129] It should be noted that the reference Fig.14 As shown, for the intermediate passivation layer 131, the sum of the silicon content ratio, the metal content ratio and the oxygen content ratio may be 100% or may not be 100%. In the case where the sum of the silicon content ratio, the metal content ratio and the oxygen content ratio is not 100%, the intermediate passivation layer 131 also contains other impurity elements, such as hydrogen, so that the intermediate passivation layer 131 also has a hydrogen passivation effect on the cross section 110c. It is worth noting that in the technology for forming the second passivation layer 121, it is possible to make the second passivation layer 121 contain other impurity elements in addition to silicon, oxygen and metal elements.

[0130] In some embodiments, in combination Fig.14 and Fig.15 As shown, along the 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.

[0131] Combination Fig.14 and Fig.15 As shown, the third surface g is the interface where the first passivation layer 111 and the cross section 110c are in contact. Most of the cross section 110c is formed by the side of the substrate 160 in the split cell 110. The substrate 160 can be a silicon substrate material. Based on this, the content of silicon element at the third surface g where the first passivation layer 111 and the cross section 110c are in contact is designed to be higher than that at the first surface e. Compared with the first surface e, it is beneficial to enrich the silicon element at the third surface g, thereby facilitating the further improvement of the lattice adaptability at the interface where the first passivation layer 111 and the cross section 110c are in contact by increasing the content of silicon element at the third surface g, further reducing the defect state density at the third surface g, and further improving the passivation effect of the first passivation layer 111 on the cross section 110c. Moreover, in order to make the content of silicon element at the third surface g higher than that at the first surface e, the content of oxygen element at the third surface g is designed to be lower than that at the first surface e, so as to ensure the high passivation effect of the first passivation layer 111 on the cross section 110c.

[0132] In some embodiments, in combination Fig.14 and Fig.15 As shown, in the direction Z from the first passivation layer 111 to the second passivation layer 121, the content of silicon in the first passivation layer 111 shows a decreasing trend, and the content of oxygen in the first passivation layer 111 shows an increasing trend. In this way, both silicon and oxygen in the first passivation layer 111 show a trend change, that is, a gradual change, which is conducive to improving the performance stability of the first passivation layer 111 and avoiding performance mutations caused by sudden changes in the content of elements in the first passivation layer 111.

[0133] It should be noted that the above has already described in detail the “increasing trend”, “specific circumstances included in the increasing trend”, “decreasing trend” and “specific circumstances included in the decreasing trend”. The description that the content of silicon element in the first passivation layer 111 shows a decreasing trend and the content of oxygen element in the first passivation layer 111 shows an increasing trend will not be repeated here.

[0134] In some embodiments, reference Fig.14 As shown, along the 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 the oxygen element 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.

[0135] refer to Fig.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 content of the oxygen element at the second surface f is designed to be higher than that at the fourth surface h, which is conducive to enriching the oxygen element at the second surface f compared to the fourth surface h, thereby making it more conducive to more oxygen atoms to migrate to the cross section 110c, so as to improve the passivation effect of the passivation layer 101 on the cross section 110c. Moreover, in order to make the content of the oxygen element at the second surface f higher than that at the fourth surface h, the content of the metal element 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.

[0136] In some embodiments, in combination Fig.14 and Fig.15As shown, in the direction Z from the first passivation layer 111 to the second passivation layer 121, the content of oxygen in the second passivation layer 121 shows a decreasing trend, and the content of metal in the second passivation layer 121 shows an increasing trend. In this way, both the oxygen and metal elements in the second passivation layer 121 show a trend change, that is, a gradual change, which is conducive to improving the performance stability of the second passivation layer 121 and avoiding performance mutations caused by sudden changes in the content of elements in the second passivation layer 121.

[0137] It should be noted that the above has already described in detail the “increasing trend”, “specific circumstances included in the increasing trend”, “decreasing trend” and “specific circumstances included in the decreasing trend”. The relevant description that the content of oxygen element in the second passivation layer 121 shows a decreasing trend and the content of metal element in the second passivation layer 121 shows an increasing trend will not be repeated here.

[0138] In some embodiments, the silicon content in the first passivation layer is 60%-98%, and the oxygen content is 2%-40%.

[0139] It should be noted that the silicon content in the first passivation layer is 60%-98%, which means that the average value of the silicon content in the first passivation layer is in the range of 60%-98%, and the silicon content in different regions of the first passivation layer may be within the average value or may not be within the average value. Similarly, the oxygen content in the first passivation layer is 2%-40%, which means that the average value of the oxygen content in the first passivation layer is in the range of 2%-40%, and the oxygen content in different regions of the first passivation layer may be within the average value or may not be within the average value.

[0140] In some cases, reference Fig.14 As shown, for the area with the largest silicon content in the first passivation layer 111, such as the third surface g, the silicon content in the area is 90%-98%, for example, the silicon content in the area can be 95%; for the area with the smallest silicon content in the first passivation layer 111, such as the first surface e, the silicon content in the area is 40%-80%, for example, the silicon content in the area can be 60%.

[0141] In some cases, reference Fig.14 As shown, for the area with the smallest oxygen content in the first passivation layer 111, such as the third surface g, the oxygen content in the area is 2%-5%, for example, the oxygen content in the area can be 3%; for the area with the largest oxygen content in the first passivation layer 111, such as the first surface e, the oxygen content in the area is 20%-60%, for example, the oxygen content in the area can be 40%.

[0142] It should be noted that, for the first passivation layer, the sum of the silicon content and the oxygen content may be 100% or may not be 100%. In the case where the sum of the silicon content and the oxygen content is not 100%, the first passivation layer also contains other impurity elements, such as hydrogen, so that the first passivation layer also has a hydrogen passivation effect on the cross section. It is worth noting that in the technology for forming the first passivation layer, it is possible that the first passivation layer contains other impurity elements in addition to silicon, oxygen and metal elements.

[0143] In some embodiments, the metal element content in the second passivation layer is 45%-65%, and the oxygen element content is 35%-55%.

[0144] It should be noted that the percentage of metal elements in the second passivation layer being 45%-65% means: the numerical range of the average value of the percentage of metal elements in the second passivation layer is 45%-65%, and the percentage of metal elements in different regions of the second passivation layer may be within the average value or may not be within the average value. Similarly, the percentage of oxygen elements in the second passivation layer being 35%-55% means: the numerical range of the average value of the percentage of oxygen elements in the second passivation layer is 35%-55%, and the percentage of oxygen elements in different regions of the second passivation layer may be within the average value or may not be within the average value.

[0145] In some cases, reference Fig.14 As shown, for the area with the largest metal element content in the second passivation layer 121, such as the fourth surface h, the metal element content in this area is 55%-75%, for example, the metal element content in this area can be 70%; for the area with the smallest metal element content in the first passivation layer 111, the metal element content in this area is 25%-50%, for example, the metal element content in this area can be 30%.

[0146] In some cases, reference Fig.14 As shown, for the area with the smallest oxygen content in the second passivation layer 121, the oxygen content in the area is 25%-45%, for example, the oxygen content in the area may be 30%; for the area with the largest oxygen content in the second passivation layer 121, the oxygen content in the area is 50%-70%, for example, the oxygen content in the area may be 55%.

[0147] It should be noted that the reference Fig.14As shown, for the second passivation layer 121, the sum of the silicon content ratio and the metal content ratio may be 100% or may not be 100%. In the case where the sum of the silicon content ratio and the metal content ratio is not 100%, the second passivation layer 121 also contains other impurity elements, such as hydrogen, so that the second passivation layer 121 also has a hydrogen passivation effect on the cross section 110c. It is worth noting that in the technology for forming the second passivation layer 121, it is possible to make the second passivation layer 121 contain other impurity elements in addition to silicon, oxygen and metal elements.

[0148] In some embodiments, the first passivation layer may be Si a O b Material, a / b∈[1.5, 49], where a / b represents the ratio of the content of silicon element to that of oxygen element in the first passivation layer.

[0149] In some embodiments, the intermediate passivation layer may be SiAl i O j Material, i / j∈[0.04, 1.31], where i / j represents the ratio of the content of aluminum element and oxygen element in the intermediate passivation layer.

[0150] In some embodiments, the second passivation layer may be Al m O n Material, m / n∈[1, 1.2], wherein m / n represents the ratio of the content of aluminum element to the content of oxygen element in the second passivation layer.

[0151] It should be noted that the mathematical formulas containing "a" and "b" in this article are a O b represents the element content ratio of silicon element and oxygen element in the first passivation layer. The mathematical formula containing "i" and "j" in this article is SiAl i O j represents the element content ratio of aluminum element and oxygen element in the second passivation layer. The mathematical formula Al containing "m" and "n" in this article is m O n Indicates the element content ratio of aluminum and oxygen in the intermediate passivation layer, Si a O b 、SiAl i O j and Al m O n None of them are strict chemical formulas or chemical structures, so Si a O b Material, 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.

[0152] As used herein, the term "non-stoichiometric compound" means and includes a compound having a certain element composition that cannot be represented by a ratio of well-defined natural numbers and does not violate the law of definite ratios. Among them, the content of each element in the first passivation layer, the second passivation layer and the intermediate passivation layer can be confirmed by testing and measuring using X-ray energy spectrometry (EDS, Energy Dispersive Spectrometer), electron energy loss spectroscopy (EELS, Electron energy loss spectroscopy) or secondary ion mass spectrometry (SIMS, Secondary Ion Mass Spectroscopy). For example, a specific line area or area area is selected for testing using a measuring device.

[0153] In some embodiments, the sliced ​​cells may include IBC cells (Interdigitated Back Contact), TOPCON (Tunnel Oxide Passivated Contact), or PERC cells (Passivated emitter and real cell).

[0154] In some embodiments, reference Figures 3 to 5 , at least some of the split cells 110 have side surfaces 110d that have not been split; Fig.16 As shown, the split battery 110 includes: a substrate 120, the substrate 120 has 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; a side passivation film 150, located on the side 110d, the side 110d passivation film and the first passivation film 130 contain the same material, or the side 110d passivation film and the second passivation film 140 contain the same material.

[0155] It should be noted that the reference Figures 3 to 5 Each of the split cells 110 has a side surface 110d that has not been split. In practical applications, there are sections 110c formed by the splitting of the four side surfaces of some of the split cells 110. For example, Figure 5The entire solar cell 100 is divided into 9 sub-cells 110 in a 3*3 array arrangement, and the four side surfaces of the sub-cell 110 located in the middle are all cross sections 110c.

[0156] In some examples, reference Fig.16 As shown, the side passivation film 150, the first passivation film 130 and the second passivation film 140 contain the same material, then 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.

[0157] In other examples, reference Fig.16 As shown, the first passivation film 130 and the second passivation film 140 may also be formed by different manufacturing processes, and the side passivation film 150 may be formed by the same manufacturing process as one of the first passivation film 130 and the second passivation film 140 .

[0158] It should be noted that the reference Fig.16 As shown, the specific structure of the side passivation film 150 is different from the specific structure 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 part of the film layer in the side passivation film 150 is different from the material of at least part of the film layer in the passivation layer 101.

[0159] In some cases, reference Fig.16 As shown, the side passivation film 150 and the passivation layer 101 are not formed by the same manufacturing process.

[0160] In some embodiments, reference Fig.16 As shown, the side passivation film 150 may be a stacked structure of a first side passivation film, a second side passivation film, and a third side passivation film stacked in a direction perpendicular to the second direction Y. In one example, the material of the first side passivation film may include a silicon material, the material of the second side passivation film may include an aluminum oxide material, and the material of the third side passivation film may include a silicon nitride material; wherein, in the direction perpendicular to the second direction Y, the thickness of the second side passivation film may be 5 nm.

[0161] In some embodiments, reference Fig.16 As shown, the side passivation film 150 may be a single-layer structure, and the material of the side passivation film 150 includes silicon oxynitride material. In one example, the thickness of the side passivation film 150 in the direction perpendicular to the second direction Y may be 70 nm.

[0162] The following explanation is given using a TOPCON cell as an example.

[0163] In some embodiments, reference Fig.17 As shown, the base 120 may include: a substrate 160, the substrate 160 has a third surface 160a and a fourth surface 160b opposite to each other along the second direction Y, the third surface 160a is close to the first surface 120a, and the fourth surface 160b is close 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 a side of the tunneling dielectric layer 180 away from the fourth surface 160b. Among them, the first passivation film 130 is located on a side of the emitter 170 away from the third surface 160a, and the second passivation film 140 is located on a 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 after surface hydroxylation.

[0164] In some cases, reference Fig.17 As shown, the substrate 160 is a silicon base material, such as one or more of single crystal silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon. In some examples, the substrate 160 may be an N-type semiconductor substrate, the substrate 160 may include an N-type doping element (such as phosphorus, arsenic, antimony, etc.), the emitter 170 may include a P-type doping element, and the emitter 170 forms a PN junction with the substrate 160.

[0165] In some cases, reference Fig.17 As shown, the split cell 110 may further include: a first electrode 122 , the first electrode 122 being 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 .

[0166] In some cases, reference Fig.17 As shown, the split battery 110 may further include: a second electrode 123 , the second electrode 123 being 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 .

[0167] In the above-mentioned various embodiments, in some embodiments, the first passivation film and the second passivation film can both be a single-layer structure or a stacked-layer structure, and the materials of the first passivation film 130 and the second passivation film 140 can both be at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride oxide, titanium oxide, hafnium oxide or aluminum oxide.

[0168] The embodiment of the present disclosure further provides a photovoltaic module, which is used to convert received light energy into electrical energy. Fig.18 and Fig.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 above embodiment, or, is formed by connecting multiple solar cells 40 provided in the above embodiment; a packaging film 41, which is used to cover the surface of the battery string; a cover plate 42, which is used to cover the surface of the packaging film 41 away from the battery string.

[0169] It should be noted that the solar cells are electrically connected to form a plurality of cell strings, and the plurality of cell strings are electrically connected in series and / or in parallel. Since the solar cells include sliced ​​cells, and the sliced ​​cells are formed by segmenting the whole solar cell, the power loss of the photovoltaic module can be improved by the current drop of the sliced ​​cells, so as to improve the photoelectric conversion efficiency of the photovoltaic module.

[0170] In one or more embodiments, reference Fig.19 As shown, multiple battery strings may be electrically connected via conductive ribbons 402 . Fig.19 Only one positional relationship between solar cells is illustrated, that is, the arrangement direction of the electrodes with the same polarity of the cells is the same, or the electrodes with positive polarity of each cell are arranged toward the same side, so that the conductive tape connects different sides of two adjacent cells. In some embodiments, the cells can also be arranged in the order of electrodes with different polarities facing the same side, that is, the electrodes of multiple adjacent cells are arranged in the order of the first polarity, the second polarity, and the first polarity, and the conductive tape connects two adjacent cells on the same side.

[0171] In one or more embodiments, no intervals are provided between the battery cells, that is, the battery cells overlap each other.

[0172] In one or more embodiments, the encapsulation film includes a first encapsulation layer and a second encapsulation layer, the first encapsulation layer covers one of the front side or the back side of the solar cell, and the second encapsulation layer covers the other of the front side or the back side of the solar cell. Specifically, at least one of the first encapsulation layer or the second encapsulation layer can be an organic encapsulation film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene co-elastomer (POE) film or a polyethylene terephthalate (PET) film.

[0173] In some cases, there is a boundary line between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, the photovoltaic module is formed and there is no longer the concept of the first encapsulation layer and the second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film.

[0174] In one or more embodiments, the cover plate may be a cover plate with a light-transmitting function such as a glass cover plate, a plastic cover plate, etc. Specifically, the surface of the cover plate facing the encapsulation film may be a concave-convex surface, thereby increasing the utilization rate of the incident light. The cover plate includes a first cover plate and a second cover plate, the first cover plate is opposite to the first encapsulation layer, and the second cover plate is opposite to the second encapsulation layer.

[0175] In one or more embodiments, reference Fig.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 the photovoltaic module, by setting the main grids of two adjacent solar cells 40 in the battery string to be staggered in the direction Y, different potentials of the photovoltaic module can be tested, thereby improving the reliability of the test results.

[0176] In one or more embodiments, photovoltaic cells include, but are not limited to, PERC cells (Passivated Emitter Rear Cell), IBC cells (Interdigitated Back Contact), TOPCon cells (Tunnel Oxide Passivated Contact), HIT / HJT cells (Heterojunction Technology heterojunction cells), solar thin-film cells, and stacked cells, or any combination thereof. Among them, solar thin-film cells include, but are not limited to, perovskite solar thin-film cells, copper indium selenide solar thin-film cells, gallium arsenide solar thin-film cells, and cadmium sulfide solar thin-film cells. Stacked cells include, but are not limited to, perovskite cells superimposed on crystalline silicon cells, perovskite cells superimposed on perovskite cells, and perovskite cells superimposed on thin-film cells.

[0177] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for realizing the present disclosure, and in practical applications, various changes can be made to them in form and details without departing from the spirit and scope of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, so the protection scope of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A method for preparing a solar cell, characterized in that: include: Providing a whole solar cell; wherein the whole solar cell includes a region to be divided; Using a first laser device to form positioning grooves at both ends of the area to be divided; Using a second laser device to heat the area to be divided starting from the positioning groove until the other positioning groove ends; A spray device is used to spray a cooling liquid onto the heated area to be split, so that the whole solar cell is split along a first direction in the area to be split to form at least two split cells; wherein the cooling liquid includes an oxidizing substance, the first direction intersects with a second direction, the second direction is the thickness direction of the split cell, the split cell includes a sub-front side and a sub-back side arranged opposite to each other along the second direction, and a cross section formed by the whole solar cell being split along the first direction, two complementary angles are formed between the cross section and the plane where the sub-back side is located, one of the angles being an acute angle, the whole solar cell has a front side and a back side arranged opposite to each other along the second direction, the sub-front side of the at least two split cells formed based on the same whole solar cell is a partial area of ​​the front side, and the sub-back side of the at least two split cells formed based on the same whole solar cell is a partial area of ​​the back side; the cross section is a silicon surface after surface hydroxylation; A passivation layer is formed on the cross section.

2. The preparation method according to claim 1, characterized in that The oxidizing substance includes H2O2 or O3.

3. The preparation method according to claim 2, characterized in that The concentration of the oxidizing substance in the cooling liquid is in the range of 0.5%-50%.

4. The preparation method according to claim 1, characterized in that The spraying device includes a nozzle; In the step of spraying cooling liquid onto the heated area to be segmented using the spray 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.

5. The preparation method according to claim 1, characterized in that The laser temperature of the second laser device is in the range of 150°C to 250°C.

6. A solar cell, characterized in that: include: A split cell, wherein at least two of the split cells are formed by splitting the same whole solar cell along a first direction, the whole solar cell having a front side and a back side oppositely arranged along a second direction, and the split cell having a sub-front side and a sub-back side oppositely arranged along the second direction, the sub-front side of the at least two split cells formed based on the same whole solar cell being a partial area of ​​the front side, and the sub-back side of the at least two split cells formed based on the same whole solar cell being a partial area of ​​the back side; The second direction is the thickness direction of the split battery, and the first direction intersects the second direction. The split battery has a cross-section formed by the segmentation process. The cross-section and the plane where the sub-back surface is located form two complementary angles, one of which is an acute angle. The cross-section is a silicon surface after surface hydroxylation. The passivation layer is located on the cross section.

7. The solar cell according to claim 6, characterized in that The acute angle ranges from 45° to 80°.

8. The solar cell according to claim 6, wherein Along the 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 material, the second passivation layer contains metal oxide material, the metal elements in the metal oxide material include at least one of Al element, Ti element, Zn element, Zr element, Hf element, Mo element, W element or Ni element, and the third direction is perpendicular to the cross-section.

9. The solar cell according to claim 8, characterized in that The passivation layer further includes an intermediate passivation layer, which is located between the first passivation layer and the second passivation layer. Both the intermediate passivation layer and the first passivation layer contain silicon elements, and the intermediate passivation layer and the second passivation layer contain the same metal element.

10. The solar cell according to claim 9, characterized in that The material of the intermediate passivation layer includes an oxide containing the silicon element and the metal element.

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