Solar cell and method of manufacturing the same, photovoltaic module

Abstract

The present disclosure relates to the field of photovoltaic technology, and provides a solar cell, a preparation method thereof and a photovoltaic module, so as to reduce the influence of laser cutting on the film layer near the cutting area as much as possible, thereby improving the efficiency and yield of the solar cell. The solar cell comprises a split cell, wherein the split cell comprises a first side and a second side arranged in a thickness direction, and a third side connecting the first side and the second side, the third side comprises a split side, at least one end of the part of the split side close to the first side and / or the second side is provided with a groove, and the groove is provided with an amorphous carbon film; and a passivation layer covering the amorphous carbon film and the part of the split side not provided with the amorphous carbon film.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of photovoltaic technology, in particular to a solar cell, a preparation method thereof, and a photovoltaic module. BACKGROUND

[0002] Currently, laser cutting combined with thermal cracking is mostly used to achieve the cutting of solar cells. However, the laser cutting uses high laser energy, which can cause damage to the film layer (for example, a passivation layer) near the cutting area of the solar cell, thereby affecting the efficiency and yield of the solar cell. SUMMARY

[0003] The present disclosure provides a solar cell, a preparation method thereof, and a photovoltaic module, so as to reduce the influence of laser cutting on the film layer near the cutting area as much as possible, thereby improving the efficiency and yield of the solar cell.

[0004] According to some embodiments of the present disclosure, the present disclosure provides a solar cell, comprising:

[0005] A split cell, wherein the split cell comprises a first side and a second side arranged in a thickness direction, and a third side connecting the first side and the second side, the third side comprises a split side, at least one end of the part of the split side close to the first side and / or the second side is provided with a groove, and the groove is provided with an amorphous carbon film.

[0006] A passivation layer covering the amorphous carbon film and the part of the split side not provided with the amorphous carbon film.

[0007] According to some embodiments of the present disclosure, the split cell further comprises a substrate and a first film layer structure.

[0008] The substrate comprises a front surface and a back surface arranged in a thickness direction of the substrate, and a side surface connecting the front surface and the back surface; and the first film layer structure is arranged on the back surface.

[0009] The first side is a side where the front surface is located, the second side is a side where the first film layer structure is away from the substrate, the split side is a whole formed by a side of the first film layer structure close to the passivation layer and the side surface in contact with the passivation layer, and the groove is formed between the side of the first film layer structure close to the passivation layer and the passivation layer.

[0010] According to some embodiments of the present disclosure, a side surface of the first film layer structure away from the substrate is arranged flush with a side surface of the amorphous carbon film away from the substrate.

[0011] According to some embodiments of the present disclosure, the first film layer structure is arranged flush with the amorphous carbon film near the side surface of the substrate.

[0012] According to some embodiments of the present disclosure, the thickness of the first film layer structure is greater than or equal to the thickness of the amorphous carbon film.

[0013] According to some embodiments of the present disclosure, the thickness of the amorphous carbon film is 20um-30um.

[0014] According to some embodiments of the present disclosure, the thickness of the amorphous carbon film accounts for 10%-30% of the thickness of the split battery.

[0015] According to some embodiments of the present disclosure, the distance of the amorphous carbon film along a first direction is 50um-125um, and the first direction is perpendicular to the plane where the passivation layer is located.

[0016] According to some embodiments of the present disclosure, the distance of the amorphous carbon film along the first direction accounts for 0.03%-0.08% of the distance of the split battery along the first direction.

[0017] According to some embodiments of the present disclosure, the distance of the amorphous carbon film along a second direction accounts for 2%-30% of the distance of the split battery along the second direction, wherein the second direction is perpendicular to the first direction.

[0018] According to some embodiments of the present disclosure, the amorphous carbon film comprises amorphous carbon particles and glass particles.

[0019] According to some embodiments of the present disclosure, another aspect of the present disclosure provides a preparation method of a solar cell, comprising:

[0020] providing a whole solar cell; wherein the whole solar cell comprises a to-be-split region;

[0021] forming a cutting groove at at least one end of the to-be-split region by using a first laser device;

[0022] forming an amorphous carbon film at the to-be-split region, wherein the amorphous carbon film fills the cutting groove;

[0023] cutting the amorphous carbon film by using a second laser device, wherein the width of the amorphous carbon film is greater than the laser cutting width of the second laser device;

[0024] separating the to-be-segmented region so that the whole solar cell is cracked along a cutting direction of the amorphous carbon film to form at least two split cells; wherein the split cell comprises a first side and a second side arranged along a thickness direction, and a third side connecting the first side and the second side, the third side comprises a segmentation side, the segmentation side is provided with a groove at least one end of a portion close to the first side and / or the second side, and the groove is provided with an amorphous carbon film;

[0025] forming a passivation layer covering the amorphous carbon film and the portion of the segmentation side not provided with the amorphous carbon film.

[0026] According to some embodiments of the present disclosure, the forming of the amorphous carbon film in the to-be-segmented region comprises:

[0027] printing an amorphous carbon paste in the to-be-segmented region;

[0028] drying the amorphous carbon paste.

[0029] According to some embodiments of the present disclosure, the cutting depth of the second laser device is less than the thickness of the amorphous carbon film.

[0030] According to some embodiments of the present disclosure, the present disclosure further provides a photovoltaic module comprising:

[0031] a cell string connected by a plurality of solar cells according to any one of the above or connected by a plurality of solar cells formed by the preparation method according to any one of the above;

[0032] an encapsulation adhesive film for covering a surface of the cell string;

[0033] a cover plate for covering a surface of the encapsulation adhesive film away from the cell string.

[0034] The present disclosure provides a solar cell and a preparation method thereof, and a photovoltaic module. In the solar cell, an amorphous carbon film is arranged in a groove of a segmentation side of a split cell. In the process of cutting a cutting region of a whole solar cell by laser to prepare a split cell, the amorphous carbon film has an anti-ablation and stress buffering function based on its own physical properties, can effectively block the heat generated by laser cutting from being transmitted to the film layer of the segmentation side, and can protect the film layer in the segmentation side, thereby reducing the influence of laser cutting on the film layer near the cutting region as much as possible, and further improving the efficiency and yield of the solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0035] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A three-dimensional structural diagram of a solar cell without a passivation layer provided in an embodiment of this disclosure;

[0037] Figure 2 A three-dimensional structural schematic diagram of a solar cell with a passivation layer provided in an embodiment of this disclosure;

[0038] Figure 3 To remove Figure 1 A bottom view of the structure obtained after the amorphous carbon film in the middle;

[0039] Figure 4 for Figure 2 A bottom view;

[0040] Figure 5 for Figure 1 The right view;

[0041] Figure 6 A three-dimensional structural schematic diagram of another solar cell without a passivation layer provided in an embodiment of this disclosure;

[0042] Figure 7a A three-dimensional structural schematic diagram of another solar cell without a passivation layer provided in an embodiment of this disclosure;

[0043] Figure 7b A three-dimensional structural schematic diagram of another solar cell without a passivation layer provided in an embodiment of this disclosure;

[0044] Figure 8 A three-dimensional structural schematic diagram of another solar cell without a passivation layer provided in an embodiment of this disclosure;

[0045] Figure 9 A three-dimensional structural schematic diagram of another solar cell without a passivation layer provided in an embodiment of this disclosure;

[0046] Figure 10 A top view schematic diagram of a single monolithic solar cell divided into two segmented cells according to an embodiment of this disclosure;

[0047] Figure 11A top view structural schematic diagram of a single whole solar cell divided into 4 split cells according to an embodiment of the present disclosure;

[0048] Figure 12 A top view structural schematic diagram of a single whole solar cell divided into 9 split cells according to an embodiment of the present disclosure;

[0049] Figure 13 A cross-sectional schematic diagram of a solar cell according to an embodiment of the present disclosure;

[0050] Figure 14 Another cross-sectional schematic diagram of a solar cell according to an embodiment of the present disclosure;

[0051] Figure 15 Still another cross-sectional schematic diagram of a solar cell according to an embodiment of the present disclosure;

[0052] Figure 16 A cross-sectional schematic diagram of a TOPCon solar cell according to an embodiment of the present disclosure;

[0053] Figure 17 A preparation method flowchart of a solar cell according to an embodiment of the present disclosure;

[0054] Figure 18 A top view structural schematic diagram of a whole solar cell formed with a cutting groove according to an embodiment of the present disclosure;

[0055] Figure 19 Another top view structural schematic diagram of a whole solar cell formed with a cutting groove according to an embodiment of the present disclosure;

[0056] Figure 20 A top view structural schematic diagram of a whole solar cell formed with an amorphous carbon film according to an embodiment of the present disclosure;

[0057] Figure 21 A partial three-dimensional structural schematic diagram of a photovoltaic module according to an embodiment of the present disclosure;

[0058] Figure 22 A Figure 21 A cross-sectional structural schematic diagram along the direction of section NN1.

[0059] Reference signs:

[0060] Segmented battery-1, first side-S1, second side-S2, third side-S3, one side of the two first sides-S31, the other side of the two first sides-S33, second side-S32, segmentation side-S34, groove-20, amorphous carbon film-2, passivation layer-3, base of segmented battery-11, front surface of the base of segmented battery-110, back surface of the base of segmented battery-111, first film layer structure-12, one side surface of the first film layer structure 12 away from the base 11-121, one side surface of the first film layer structure 12 close to the base 11-122, one side surface of the amorphous carbon film 2 away from the base 11-21, one side surface of the amorphous carbon film 2 close to the base 11-22, first passivation layer-31, second passivation layer-32, TOPCON solar cell-4, first base of TOPCON solar cell-41, tunneling medium layer-42, doped conductive layer-43, first passivation film-44, first electrode-47, emitter-45, second passivation film-46, second electrode-48, cutting groove-5, solar cell-6, conductive strip-7, encapsulation adhesive film-8, cover plate-9, whole piece solar cell-100, to be segmented area-S, side surface-a of segmented battery after segmentation processing, side surface-b of segmented battery without segmentation processing, rounded corner-e. DETAILED DESCRIPTION

[0061] To make the objects, technical solutions and advantages of the present disclosure clearer, the technical solutions of the present disclosure will be described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present disclosure.

[0062] In the description of the embodiments of the present disclosure, the meaning of "at least one" is one or more, the meaning of "at least one layer" is one layer or more layers, the meaning of "multiple" is two or more than two, the meaning of "multiple layers" is two or more than two layers, the meaning of "multiple groups" is two or more than two groups, and the meaning of "multiple pieces" is two or more than two pieces, unless otherwise explicitly and specifically limited.

[0063] In the description of the embodiments of the present disclosure, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0064] In the description of the embodiments of the present disclosure, the term "and / or" is merely an association relationship of associated objects, and can represent three possible relationships, for example, A and / or B, which can represent three cases of existence of A, existence of A and B, and existence of B. In addition, the character " / " in this paper generally represents that the front and rear associated objects are in an "or" relationship.

[0065] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can 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 all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0066] In the description of the embodiments of the present disclosure, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present disclosure.

[0067] For example, if the device or element in the drawing is inverted, the element described as "under" or "below" or "under" or "bottom" of the other element or feature will be oriented "above" or "top" of the other element or feature. Therefore, the term "under" can cover both upward and downward orientations depending on the context in which the term is used, which will be apparent to those skilled in the art. The material can be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatially relative descriptions used herein can be interpreted accordingly.

[0068] In the description of the embodiments of the present disclosure, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0069] In the drawings corresponding to the embodiments of the present disclosure, the thickness and area of a layer are exaggerated for better understanding and ease of description. In addition, when it is described that one component is "formed substantially 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.

[0070] In the description of the embodiments of the present disclosure, when a certain component "includes" another component, unless otherwise specified, other components are not excluded, and other components can be further included. A first component on which a second component is formed or disposed, or on the surface of the first component, or on one side of the first component, can include an embodiment in which the first component and the second component are in direct contact, and can also include an embodiment in which additional components can be present between the first component and the second component, so that the first component and the second component can not be in direct contact.

[0071] For simplicity and clarity, various components can be arbitrarily drawn in different proportions. In the drawings, some layers / components can be omitted for simplicity. Unless otherwise specified, a first component on which a second component is formed or disposed means that the first component is in direct contact with the second component. Among them, the "component" mentioned above can refer to a layer, a film, a region, a portion, a structure, etc.

[0072] The embodiments of the present disclosure provide a solar cell, referring to FIG. 1, which includes: Figures 1 to 9 As shown in FIG. 1, it includes:

[0073] A split cell 1, wherein the split cell 1 includes a first side S1 and a second side S2 arranged in a thickness direction OZ, and a third side S3 connecting the first side S1 and the second side S2, the third side S3 includes a split side S34, and the split side S34 is provided with a groove 20 as shown in FIG. 2 at least one end of the part close to the first side S1 and / or the second side S2, the groove 20 is provided with an amorphous carbon film 2; a passivation layer 3 covering the amorphous carbon film 2 and the part of the split side S34 where the amorphous carbon film 2 is not provided. Figure 3 As shown in FIG. 2, the groove 20 is provided with an amorphous carbon film 2; a passivation layer 3 covering the amorphous carbon film 2 and the part of the split side S34 where the amorphous carbon film 2 is not provided.

[0074] In the embodiments of the present disclosure, the first side can be the side where the front surface of the split cell is arranged in the thickness direction, and the second side can be the side where the back surface of the split cell is arranged in the thickness direction; or the first side can be the side where the back surface of the split cell is arranged in the thickness direction, and the second side can be the side where the front surface of the split cell is arranged in the thickness direction.

[0075] In the embodiments of the present disclosure, the split cell can be obtained by cutting a whole solar cell into two, three or smaller sizes. The specific structure of the third side is determined by the shape of the split cell.

[0076] If the sliced battery is a rectangular sliced battery, the third side includes two oppositely arranged first sides and two oppositely arranged second sides; wherein the division side can be any one of the two first sides and the two second sides; or, both the two first sides or the two second sides are the division side; or, any three of the two first sides and the two second sides are the division side.

[0077] Referring to Figures 1 to 9 As shown in the figure, the third side S3 includes two oppositely arranged first sides S31 and S33, and two oppositely arranged second sides, one of which is S32, and the other of which is used as a division side S34.

[0078] When the sliced battery is formed by cutting the whole solar cell, the area where the division side is located is subjected to division processing. For example, referring to Figure 10 As shown in the figure, the whole solar cell 100 is divided into two sliced batteries 1, wherein each of the two sliced batteries 1 includes one division side, i.e., a side a subjected to division processing, and a side b not subjected to division processing. The corners of the four sides of the whole solar cell 100 are rounded corners e, based on which the corners of the side b not subjected to division processing in the sliced battery 1 are still rounded corners e, but the corners of the side a subjected to division processing in the sliced battery 1 do not have rounded corners.

[0079] Referring to Figure 11 As shown in the figure, the whole solar cell 100 is divided into four sliced batteries 1, wherein each of the four sliced batteries includes two division sides, i.e., two sides a subjected to division processing, and a side b not subjected to division processing.

[0080] Referring to Figure 12 As shown in the figure, the whole solar cell 100 is divided into nine sliced batteries labeled as C1-C9, wherein the sliced batteries C1, C2, C7, and C9 each include two division sides, i.e., two sides a subjected to division processing, the sliced batteries C2, C4, C6, and C8 each include three division sides, i.e., three sides a subjected to division processing, and a side b not subjected to division processing; and the sliced battery C5 includes four division sides, i.e., four sides a subjected to division processing.

[0081] In the embodiments of the present disclosure, the portion of the division side S34 close to at least one end of the first side S1 and / or the second side S2 is provided with a groove, including: referring to Figure 7a As shown in the figure, one end of the portion of the division side S34 close to the first side S1 is provided with a groove; or, referring to Figure 7b As shown in the figure, both ends of the portion of the division side S34 close to the first side S1 are provided with grooves; or, referring to Figure 1 As shown in the figure, one end of the portion of the division side S34 close to the second side S2 is provided with a groove; or, referring to Figure 6As shown, the two ends of the portion of the splitting side S34 close to the second side S2 are provided with grooves; or, referring to Figure 8 As shown, the one end of the portion of the splitting side S34 close to the first side S1 and the one end of the portion of the splitting side S34 close to the second side S2 are provided with grooves, respectively; or, referring to Figure 9 As shown, the two ends of the portion of the splitting side S34 close to the first side S1 and the two ends of the portion of the splitting side S34 close to the second side S2 are provided with grooves, respectively.

[0082] The type of the split battery is not limited, and the split battery can include, but is not limited to, one or any combination of a PERC (Passivated Emitter Rear Cell) battery, an IBC (Interdigitated Back Contact) battery, a TOPCon (Tunnel Oxide Passivated Contact) battery, a HIT / HJT (Heterojunction Technology) battery, a solar thin film battery, or a stacked battery. The solar thin film battery includes, but is not limited to, a perovskite solar thin film battery, a copper-indium-selenium solar thin film battery, a gallium arsenide solar thin film battery, or a cadmium sulfide solar thin film battery. The stacked battery includes, but is not limited to, a perovskite battery stacked with a crystalline silicon battery, a perovskite battery stacked with a perovskite battery, or a perovskite battery stacked with a thin film battery.

[0083] The amorphous carbon (a-C) film is an ideal material for resisting laser ablation, and has the following characteristics: first, high thermal stability, the melting point of the amorphous carbon film is greater than 3000°C, which is much higher than the laser cutting temperature (usually less than 2000°C), so it can effectively block the heat generated by laser cutting from being transmitted to the film layer inside the splitting side. Second, low thermal conductivity, the thermal conductivity of the amorphous carbon film (1 W / m·K~5 W / m·K) is significantly lower than that of AlOx (30 W / m·K) and SiNx (20 W / m·K), which can effectively inhibit the heat diffusion to the film layer inside the splitting side. Third, chemical inertness, the amorphous carbon film is compatible with the passivation layer (AlOx or SiNx) without interface reaction risk. Fourth, optical transparency, the transmittance of the amorphous carbon film in the infrared waveband (laser wavelength 355 nm~532 nm) is greater than 90%, which does not affect the laser cutting precision.

[0084] The solar cell provided by the embodiments of the present disclosure is provided with an amorphous carbon film in the groove on the splitting side of the split cell. In the process of cutting the cutting area of the whole solar cell by laser to prepare the split cell, based on the physical properties of the amorphous carbon film, the amorphous carbon film has the functions of resisting ablation and stress buffering, can effectively block the heat generated by laser cutting from being transmitted to the film layer on the splitting side, realize the protection of the film layer in the splitting side, thereby reducing the influence of laser cutting on the film layer near the cutting area as much as possible, and further improve the efficiency and yield of the solar cell.

[0085] In some embodiments, referring to Figures 13 to 15 As shown in the figure, the split cell 1 includes a substrate 11 and a first film layer structure 12; the substrate 11 further includes a front surface 110 and a back surface 111 arranged along the thickness direction of the substrate 11, and a side surface connecting the front surface 110 and the back surface 111; the first film layer structure 12 is arranged on the back surface 111; wherein the first side is the side where the front surface is located, the second side is the side where the first film layer structure 12 faces away from the substrate 11, and the splitting side is the whole formed by the side of the first film layer structure 12 close to the passivation layer 3 and the side in contact with the passivation layer 3; a groove is formed between the side of the first film layer structure 12 close to the passivation layer 3 and the passivation layer 3.

[0086] The substrate is used to receive incident light and generate photo-generated carriers. The substrate can be a semiconductor substrate. For example, the substrate can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, which can be any one of a group V element such as phosphorus (P) element, bismuth (Bi) element, antimony (Sb) element or arsenic (As) element. The P-type semiconductor substrate is doped with a P-type element, which can be any one of a third main group element such as boron (B) element, aluminum (Al) element, gallium (Ga) element or indium (In) element.

[0087] In the embodiments of the present disclosure, the material of the substrate can be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, for example, it can be silicon or germanium. Among them, the elemental semiconductor material can be single-crystalline, polycrystalline, amorphous or microcrystalline (a state of both single-crystalline and amorphous, referred to as microcrystalline), for example, silicon can be at least one of single-crystalline silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon. Alternatively, the material of the substrate can also be a compound semiconductor material. Common compound semiconductor materials include but are not limited to silicon germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride and copper indium selenium, etc.

[0088] The specific structure of the first film layer structure depends on the type of the split cell. For example, if the split cell is a TOPCon cell, the first film layer structure can include a tunneling dielectric layer, a doped conductive layer and a passivation film arranged in turn on the back surface of the substrate.

[0089] In the segmented solar cell provided in this embodiment, an amorphous carbon film is disposed within a groove formed between the first film structure and the passivation layer on the side near the passivation layer. Thus, during the process of fabricating segmented solar cells by laser cutting the cutting area of ​​the entire solar cell, the amorphous carbon film, based on its inherent physical properties, possesses ablation resistance and stress buffering functions. It can effectively block the heat generated by laser cutting from being transferred to the first film structure, thereby protecting the first film structure and minimizing the impact of laser cutting on the first film structure near the cutting area, thereby improving the efficiency and yield of the solar cell.

[0090] It should be noted that if the cell is a TOPCon cell, the PN junction of the TOPCon cell is located on the front side of the substrate. In related technologies, when forming cell segments by front-side cutting, the laser thermal effect will directly act on the PN junction region, which can easily cause problems such as carrier recombination and microcrack propagation, resulting in a loss of cell efficiency (approximately 0.1% to 0.4%).

[0091] The segmented cell disclosed herein can be formed by back-side cutting, thereby avoiding the adverse effects of front-side cutting on the PN junction region, reducing efficiency loss by approximately 0.03% to 0.08%, and further improving cell efficiency and yield.

[0092] In some embodiments, reference Figure 13 and Figure 14 As shown, the surface 121 of the first film structure 12 facing away from the substrate 11 is flush with the surface 21 of the amorphous carbon film 2 facing away from the substrate 11, thereby better protecting the side of the first film structure facing away from the substrate.

[0093] To protect the side of the first membrane structure closest to the substrate and further enhance the overall protective effect of the first membrane structure, reference is made. Figure 14 As shown, the surface 122 of the first film structure 12 near the substrate 11 is flush with the surface 22 of the amorphous carbon film 2 near the substrate 11.

[0094] It should be noted that if the surface of the first film layer structure facing away from the substrate is flush with the surface of the amorphous carbon film facing away from the substrate, and the surface of the first film layer structure facing away from the substrate is flush with the surface of the amorphous carbon film facing away from the substrate, then the thickness of the first film layer structure is the same as the thickness of the amorphous carbon film.

[0095] In other embodiments, to avoid the amorphous carbon film affecting the substrate and to reduce the cost of the amorphous carbon film, reference is made to... Figure 14 and Figure 15 As shown, the thickness h2 of the first film structure 12 is greater than or equal to the thickness h of the amorphous carbon film 2.

[0096] It should be noted that, with reference to Figure 14 As shown in FIG. 2, if the thickness h2 of the first film layer structure 12 is greater than the thickness h of the amorphous carbon film 2, the side surface 121 of the first film layer structure 12 away from the substrate 11 is arranged flush with the side surface 21 of the amorphous carbon film 2 away from the substrate 11, and the side surface 122 of the first film layer structure 12 close to the substrate 11 is closer to the substrate 11 than the side surface 22 of the amorphous carbon film 2 close to the substrate 11.

[0097] In some embodiments, the thickness of the amorphous carbon film is 20 um to 30 um. For example, the thickness of the amorphous carbon film is 20 um, 22 um, 24 um, 26 um, 28 um, or 30 um, so as to reduce the cost of the amorphous carbon film and protect the first film layer structure.

[0098] In order to protect the first film layer structure in laser cutting and minimize the impact on the original structure, in some embodiments, with reference to Figure 5 As shown in FIG. 2, the ratio of the thickness h of the amorphous carbon film 2 to the thickness h1 of the split battery is 10% to 30%. For example, the ratio of the thickness of the amorphous carbon film to the thickness of the split battery is 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, or 30%.

[0099] In some embodiments, in order to reduce the cost of the amorphous carbon film and protect the first film layer structure, with reference to Figure 4 As shown in FIG. 2, the distance d1 of the amorphous carbon film 2 along the first direction OX is 50 um to 125 um, and the first direction OX is perpendicular to the plane where the passivation layer 3 is located. For example, the distance of the amorphous carbon film along the first direction is 50 um, 55 um, 60 um, 65 um, 70 um, 75 um, 80 um, 85 um, 90 um, 95 um, 100 um, 105 um, 110 um, 115 um, 120 um, or 125 um.

[0100] In order to minimize the impact on the original split battery structure and also protect the first film layer structure, in some embodiments, with reference to Figure 4 As shown in FIG. 2, the ratio of the distance d1 of the amorphous carbon film 2 along the first direction OX to the distance d2 of the split battery along the first direction OX is 0.03% to 0.08%.

[0101] For example, if the distance between the cell segments along the first direction is 156 mm and the distance between the amorphous carbon film and the cell segments along the first direction is 50 μm, then the ratio of the distance between the amorphous carbon film and the cell segments along the first direction is 50 μm / 156 mm = 0.032%. If the distance between the cell segments and the cell segments along the first direction is 156 mm and the distance between the amorphous carbon film and the cell segments along the first direction is 125 μm, then the ratio of the distance between the amorphous carbon film and the cell segments along the first direction is 125 μm / 156 mm = 0.08%.

[0102] In some embodiments, to balance the cost of amorphous carbon films and the protection of the first film structure, reference is made to... Figure 4 As shown, the ratio of the distance d3 of the amorphous carbon film 2 along the second direction OY to the distance d4 of the segmented cell along the second direction OY is 2% to 30%, wherein the second direction OY is perpendicular to the first direction OX. For example, the ratio of the distance of the amorphous carbon film along the second direction to the distance of the segmented cell along the second direction is 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, or 30%.

[0103] In some embodiments, the amorphous carbon film comprises amorphous carbon particles and glass particles. The amorphous carbon film can be formed by partial printing and drying of an amorphous carbon film slurry, which comprises amorphous carbon powder, glass powder, and an organic solvent. The amorphous carbon particle size is 50 nm to 100 nm, and the glass powder can be... The system has a softening point of 450℃~550℃ and a glass powder mass ratio of 5%~10%. By doping with glass powder, the formed amorphous carbon film can be made to have a certain degree of corrosivity, thereby corroding part of the film layer below the amorphous carbon film.

[0104] In some embodiments, reference Figure 15 As shown, along the thickness direction of the passivation layer 3, the passivation layer 3 includes at least a first passivation layer 31 and a second passivation layer 32 stacked together; wherein, the first passivation layer contains silicon oxide material, and the second passivation layer contains metal oxide material, wherein the metal element in the metal oxide material includes at least one of Al (aluminum), Ti (titanium), Zn (zinc), Zr (zirconium), Hf (hafnium), Mo (molybdenum), W (tungsten) or Ni (nickel).

[0105] In this way, on the one hand, the first passivation layer is designed to contain a silicon oxide material, and the silicon oxide material is used to chemically passivate the cleavage side, for example, by saturating dangling bonds on the cleavage side with oxygen atoms in the first passivation layer, so as to reduce the defect state density of the cleavage side, reduce the recombination center of the cleavage side, and reduce the carrier recombination probability; on the other hand, the second passivation layer is designed to contain a metal oxide material, and the metal element in the metal oxide material includes at least one of Al, Ti, Zn, Zr, Hf, Mo, W or Ni, and the metal element in the second passivation layer itself has a high density of fixed charges, which can generate a larger electric field, thereby effectively passivating the cleavage side by field effect, for example, generating a larger band bending between the second passivation layer and the cleavage side, hindering the migration of minority carriers to the cleavage side, reducing the concentration of minority carriers at the cleavage side, thereby facilitating the reduction of the recombination probability of majority carriers and minority carriers at the cleavage side.

[0106] At the same time, the amorphous carbon film is compatible with the first passivation layer and the second passivation layer, and there is no risk of interface reaction. The first passivation layer and the second passivation layer work together to significantly improve the photoelectric conversion efficiency of the split cell, thereby improving the photoelectric conversion efficiency of the solar cell.

[0107] In addition, the high density of the silicon oxide material is conducive to improving the density of the first passivation layer, so that the film layer stability of the first passivation layer is high, and the cleavage side is protected by the first passivation layer, for example, external impurities can be prevented from invading the cleavage side.

[0108] In addition, the silicon oxide material also has good PID (Potential Induced Degradation) effect. Since the packaging material of the photovoltaic module formed based on the solar cell is difficult to achieve 100% isolation from the outside world, water vapor may enter the solar cell through the packaging material or backsheet used as the edge sealing purpose in a humid environment. At this time, the glass in the packaging material will produce sodium ions, which will move to the surface of the solar cell under the action of an external electric field to produce a PID phenomenon, resulting in a decrease in the photoelectric conversion efficiency of the solar cell. The silicon oxide material has good density and insulation, so it has a good effect on preventing water vapor from entering the split cell, thereby having a good PID effect.

[0109] In this way, even if the packaging material of the photovoltaic module is difficult to achieve complete insulation, and water vapor enters the environment where the solar cell is located through the packaging material used as the edge sealing purpose, the film layer composed of the silicon oxide material can prevent the sodium ions in the glass in the packaging material from moving to the cleavage side, thereby preventing the occurrence of the PID phenomenon and maintaining a high photoelectric conversion rate of the solar cell.

[0110] In some cases, reference is made to Figure 15 As shown in FIG. 2, the second passivation layer 32 is disposed on the side of the first passivation layer 31 away from the split side of the sub-cell, and the first passivation layer 31 covers the amorphous carbon film 2 and the portion of the split side on which the amorphous carbon film 2 is not disposed.

[0111] In this way, the migration path of the oxygen atoms in the first passivation layer to the surface defects on the split side is shortened, so as to improve the chemical passivation effect of the oxygen atoms in the first passivation layer on the split side. In addition, compared with the second passivation layer containing a metal oxide material, the lattice of the first passivation layer containing a silicon oxide material is more suitable for the lattice of the substrate in the sub-cell, so as to avoid the problem of large lattice mismatch between the split side and the second passivation layer when the split side directly contacts the second passivation layer, thereby avoiding the problem of increased surface defects caused by the lattice mismatch, and thus improving the interface passivation effect on the split side.

[0112] The metal oxide material contained in the second passivation layer is exemplified as follows.

[0113] In some examples, the metal element in the metal oxide material includes an Al element, i.e., the second passivation layer contains an aluminum oxide material. On the one hand, the aluminum oxide material enables the second passivation layer to have a high density of fixed negative charge (Q f about 10 12 cm -2 ~10 13 cm -2 ), which is conducive to improving the field passivation effect of the second passivation layer on the split side, so as to reduce the probability of recombination of the carriers at the split side, thereby facilitating the improvement of the photoelectric conversion efficiency of the sub-cell.

[0114] In other examples, the metal element in the metal oxide material includes an Mo element, i.e., the second passivation layer contains a molybdenum oxide material. On the one hand, the molybdenum oxide material enables the second passivation layer to have a high work function, which is also conducive to the second passivation layer having a good field passivation effect on the split side. On the other hand, in the technology of forming the second passivation layer containing the molybdenum oxide material, the second passivation layer also has an appropriate amount of hydrogen ions, so that the second passivation layer has a good hydrogen passivation effect on the split side.

[0115] It should be noted that the above two examples illustrate the good passivation effect of the metal oxide material in the second passivation layer on the cross-section. In practical applications, the metal element in the metal oxide material includes at least one of Al, Ti, Zn, Zr, or Hf, which can give the second passivation layer a high density of fixed negative charge to achieve a good field passivation effect on the segmented side; the metal element in the metal oxide material includes at least one of Mo, W, or Ni, which can give the second passivation layer a high density of fixed positive charge or a high work function to achieve a good field passivation effect on the segmented side.

[0116] In some embodiments, reference Figure 15 As shown, the thickness D1 of the first passivation layer 31 can be 1 nm to 10 nm. In some examples, the thickness D1 of the first passivation layer 31 can be 4 nm to 7 nm, such as 4.5 nm, 5 nm, 5.5 nm, 6 nm or 6.5 nm.

[0117] In some embodiments, reference Figure 15 As shown, the thickness D2 of the second passivation layer 32 can be 20nm to 100nm. In some examples, the thickness D2 of the second passivation layer 32 can be 40nm to 60nm, such as 45nm, 48nm, 50nm, 53nm, 55nm, or 58nm.

[0118] The following explanation uses TOPCON solar cells as an example of segmented solar cells.

[0119] In some embodiments, reference Figure 16 As shown, the TOPCON solar cell 4 includes: a first substrate 41, which includes a front side and a back side disposed along the thickness direction, and a side side connecting the front side and the back side; a tunneling dielectric layer 42, a doped conductive layer 43, a first passivation film 44, and a first electrode 47 disposed on the back side, wherein the first electrode 47 and the doped conductive layer 43 are in electrical contact; an emitter 45, a second passivation film 46, and a second electrode 48 disposed on the front side, wherein the second electrode 48 and the emitter 45 are in electrical contact; a passivation layer, wherein the segmented side includes the tunneling dielectric layer 42, the doped conductive layer 43, and the first passivation film 44 on the side near the passivation layer 3, and the side side of the first substrate 41 near the passivation layer 3, and a groove is provided at the end of the segmented side near the back side, and an amorphous carbon film 2 is disposed in the groove; the passivation layer 3 covers the amorphous carbon film 2 and the side side of the first substrate 41.

[0120] In some cases, the first substrate is a silicon substrate material, such as one or more of single crystal silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. In some examples, the first substrate can be an N-type semiconductor substrate, and the first substrate can include an N-type dopant element (such as phosphorus, arsenic, antimony, etc.), and the emitter can include a P-type dopant element, forming a PN junction with the first substrate.

[0121] In some of the above embodiments, the first passivation film and the second passivation film can each be a single layer structure or a stacked structure, and the material of the first passivation film and the second passivation film can be at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon oxynitride carbon, titanium oxide, hafnium oxide, or aluminum oxide.

[0122] The embodiments of the present disclosure also provide a method for manufacturing a solar cell, referring to FIG. 1, the method comprises the following steps: Figure 17

[0123] In step a1, a whole solar cell is provided, referring to FIG. 1, the whole solar cell 100 comprises a to-be-cut region S. Figure 18

[0124] In step a2, a first laser device is used to form a cutting groove at at least one end of the to-be-cut region.

[0125] It should be noted that the first laser device can form the cutting groove on the back surface of the whole solar cell, or the first laser device can also form the cutting groove on the front surface of the whole solar cell, or the first laser device can also form the cutting groove on the front surface and the back surface of the whole solar cell respectively, which can be selected according to actual requirements. If the type of the whole solar cell is a TOPCon cell, the cutting groove can be formed on the back surface of the whole solar cell to avoid the adverse effects of subsequent front surface laser cutting on the PN junction region, thereby further improving the cell efficiency and yield.

[0126] In the embodiments of the present disclosure, referring to FIG. 1, the cutting groove 5 is formed at one end of the to-be-cut region S, which can reduce the cost and the influence of laser on the solar cell; or referring to FIG. 2, the cutting groove 5 is formed at opposite ends of the to-be-cut region S, which is beneficial to subsequent complete separation. Figure 18 Figure 19 In the embodiments of the present disclosure, referring to FIG. 1, the cutting groove 5 is formed at one end of the to-be-cut region S, which can reduce the cost and the influence of laser on the solar cell; or referring to FIG. 2, the cutting groove 5 is formed at opposite ends of the to-be-cut region S, which is beneficial to subsequent complete separation.

[0127] In the embodiments of the present disclosure, the cutting groove can be formed by using a patterned laser to pre-mark the cutting path. The wavelength of the patterned laser is 1064 nm, and the energy density is 0.5 J / cm²~1 J / cm².

[0128] For example, the energy density is 0.5 J / cm², 0.6 J / cm², 0.7 / cm², 0.8 J / cm², 0.9 J / cm², or 1 J / cm².​​​

[0129] Reference Figure 1 As shown, the depth of the cutting groove is 2um~3um, for example, the depth of the cutting groove is 2um, 2.2um, 2.4um, 2.6um, 2.8um or 3um.

[0130] Step a3, as shown by reference 20, an amorphous carbon film 2 is formed in the region to be cut, wherein the amorphous carbon film fills the cutting groove.

[0131] In step a3, the amorphous carbon film can be formed by screen printing and other processes.

[0132] Step a4, the amorphous carbon film is cut by using a second laser device, wherein the width of the amorphous carbon film is greater than the laser cutting width of the second laser device. The second laser device can use picosecond or nanosecond laser with wavelength of 355nm~532nm, and the laser energy density is 5J / cm²~20J / cm².

[0133] The laser energy density is 5J / cm², 8J / cm², 10 / cm², 12J / cm², 14J / cm², 16J / cm² or 20J / cm². Compared with the laser used by the first laser device in step a2, the laser energy used in step a4 is very high to achieve cutting.

[0134] The laser cutting depth of the second laser device is 10%~30% of the thickness of the whole solar cell, for example, the laser cutting depth of the second laser device is 10%, 15%, 20%, 25% or 30% of the thickness of the whole solar cell.

[0135] Alternatively, the laser cutting depth of the second laser device is 15%~20% of the thickness of the whole solar cell, for example, the laser cutting depth of the second laser device is 15%, 16%, 17%, 18%, 19% or 20% of the thickness of the whole solar cell.

[0136] Reference Figure 20 As shown, in order to protect the film layer on both sides of the cutting path EE1 in step a4, the width W of the amorphous carbon film 2 is greater than the laser cutting width of the second laser device.

[0137] Step a5, the region to be cut is separated, so that the whole solar cell is cracked along the cutting direction of the amorphous carbon film to form at least two split cells; wherein the split cell includes a first side and a second side arranged in the thickness direction, and a third side connecting the first side and the second side, the third side includes a split side, at least one end of the part of the split side close to the first side and / or the second side is provided with a groove, and the groove is provided with the amorphous carbon film.

[0138] In step a5, the separation of the to-be-split region can be achieved by thermal cracking or mechanical separation, wherein the thermal cracking includes infrared heating, etc.

[0139] It should be noted that, in the case that the first side of the split battery is the side where the front surface is located, and the second side is the side where the back surface is located, if a cutting groove is formed at one end of the to-be-split region on the back surface of the whole solar cell in step a2, then in the split battery formed by steps a1 to a5, the end of the portion close to the second side of the split side is provided with a groove.

[0140] If a cutting groove is formed at one end of the to-be-split region on the front surface of the whole solar cell in step a2, and in the split battery formed by steps a1 to a5, the end of the portion close to the first side of the split side is provided with a groove.

[0141] If a cutting groove is formed at one end of the to-be-split region on the front surface and at one end of the to-be-split region on the back surface of the whole solar cell in step a2, then in the split battery formed by steps a1 to a5, the end of the portion close to the first side and the end of the portion close to the second side of the split side are both provided with grooves.

[0142] In step a6, a passivation layer is formed, covering the amorphous carbon film and the portion of the split side where no amorphous carbon film is provided.

[0143] In the embodiment of the present disclosure, by performing steps a1 to a6, the solar cell provided in the foregoing embodiment can be formed. In the preparation method, a cutting groove is first formed at least at one end of the to-be-split region by using a first laser device, and then an amorphous carbon film filling the cutting groove is formed on the to-be-split region. When the amorphous carbon film is cut by using a second laser device, since the width of the amorphous carbon film is greater than the laser cutting width of the second laser device, and the amorphous carbon film has the functions of ablation resistance and stress buffering, the heat generated by laser cutting can be effectively blocked from being transmitted to the film layer inside the split side, so as to reduce the influence of laser cutting on the film layer near the cutting area as much as possible, and further improve the efficiency and yield of the solar cell.

[0144] In some embodiments, in step a3, the amorphous carbon film is formed on the to-be-split region, including:

[0145] In step a31, the amorphous carbon paste is printed on the to-be-split region; wherein the amorphous carbon film paste includes amorphous carbon powder, glass powder and organic solvent, wherein the particle size of the amorphous carbon is 50nm-100nm.

[0146] Specifically, the particle size of the amorphous carbon is 50nm, 60nm, 70nm, 80nm, 90nm or 100nm; the glass powder can be The system has a softening point of 450-550 DEG C, and specifically, the softening point is 450 DEG C, 460 DEG C, 470 DEG C, 480 DEG C, 490 DEG C, 500 DEG C, 510 DEG C, 520 DEG C, 530 DEG C, 540 DEG C or 550 DEG C.

[0147] The mass percentage of the glass powder is 5-10%, and specifically, the mass percentage of the glass powder is 5%, 6%, 7%, 8%, 9% or 10%. By doping the glass powder, the amorphous carbon film formed has a certain corrosion property, thereby corroding part of the film layer below the amorphous carbon film.

[0148] The width of the printed amorphous carbon slurry is 100-250 um, and specifically, the width of the printed amorphous carbon slurry is 100 um, 120 um, 140 um, 160 um, 180 um, 200 um, 220 um or 250 um.

[0149] The thickness of the printed amorphous carbon slurry is 10-40 um, and specifically, the thickness of the printed amorphous carbon slurry is 10 um, 15 um, 20 um, 25 um, 30 um, 35 um or 40 um.

[0150] In step a32, the amorphous carbon slurry is subjected to drying treatment.

[0151] Specifically, the drying temperature is 150-200 DEG C, and specifically, the drying temperature is 150 DEG C, 160 DEG C, 170 DEG C, 180 DEG C, 190 DEG C or 200 DEG C. After drying, an amorphous carbon film is obtained.

[0152] It should be noted that the amorphous carbon slurry in step a31 fills the cutting groove, and the amorphous carbon slurry contains glass powder components, which can corrode part of the film layer below the amorphous carbon slurry. Therefore, after steps a31 and a32 are performed, the amorphous carbon film obtained does not protrude from the surface of the region to be divided.

[0153] The high-energy laser used in step a4 has a large loss to the solar cell. In order to reduce the loss, in some embodiments, the cutting depth of the second laser device is less than the thickness of the amorphous carbon film.

[0154] The following takes the division of a whole N-type TOPCON solar cell into two split cells as an example to provide embodiments one to three and comparative examples one to three for specific description.

[0155] The preparation method used in embodiment one of the present disclosure comprises:

[0156] Step a101, a whole piece of N-type TOPCON solar cell is prepared, the thickness of the whole piece of N-type TOPCON solar cell is H, the length is L, and the width is W0. The N-type TOPCON solar cell includes a front surface and a back surface arranged in the thickness direction, and the back surface is provided with an AlOx / SiNx passivation film.

[0157] The preparation of the N-type TOPCON solar cell generally includes: double-sided texturing of the substrate→boron diffusion on the front surface of the substrate to form an emitter→formation of a tunneling oxide layer and a polysilicon layer on the back surface of the substrate→formation of a passivation film on the front surface of the substrate→formation of a passivation film on the back surface of the substrate. The specific process method of each step can refer to the related art, which will not be described here.

[0158] Step a102, a cutting groove is formed at one end of the to-be-split region on the back surface of the whole piece of N-type TOPCON solar cell by using a patterned laser; wherein the wavelength of the laser is λ1, and the energy density is A1.

[0159] Step a103, amorphous carbon paste is screen printed on the to-be-split region on the back surface of the whole piece of N-type TOPCON solar cell, and an amorphous carbon film is formed after drying; wherein the amorphous carbon paste includes amorphous carbon powder, glass powder and organic solvent, wherein the particle size of the amorphous carbon is D, the glass powder can be The system, the softening point is R, and the mass fraction of the glass powder is F; the thickness of the printed amorphous carbon paste is W.

[0160] Step a104, a picosecond laser with a wavelength of λ2 and an energy density of A2 is used to cut the amorphous carbon film, wherein the cutting depth of the laser is Q, and the ratio of the cutting depth to the thickness H of the TOPCON solar cell is E.

[0161] Step a105, infrared heating is performed to a temperature T to complete thermal cracking, so that the whole piece of N-type TOPCON solar cell is cracked along the cutting direction of the amorphous carbon film to form two split cells.

[0162] The split cell includes a first side and a second side arranged in the thickness direction, and a third side connecting the first side and the second side, the third side includes a split side, one end of the part close to the first side of the split side is provided with a groove, and the groove is provided with an amorphous carbon film. The first side is the side where the front surface is located, and the second side is the side where the back surface is located.

[0163] Step a106, a passivation layer is formed, which covers the amorphous carbon film and the part of the split side which is not provided with the amorphous carbon film.

[0164] It should be noted that the preparation method adopted by the second and third embodiments of the present disclosure is the same as that of the first embodiment, and the difference lies in the specific process parameters adopted in each step. The detailed process parameter settings can be referred to Table 1.

[0165] The preparation method used in Comparative Example One provided by the present disclosure is different from the preparation method used in Example One provided by the present disclosure in two aspects. First, in Example One provided by the present disclosure, step a102 forms a cutting groove on the back surface of the whole N-type TOPCON solar cell, while in Comparative Example One, a cutting groove is formed on the front surface of the whole N-type TOPCON solar cell. Second, in Comparative Example One, no amorphous carbon film is provided, that is, laser cutting is directly performed on the cutting groove. The remaining preparation steps of Comparative Example One are the same as those of Example One.

[0166] The preparation methods used in Comparative Example Two and Comparative Example Three provided by the present disclosure are the same as that of Comparative Example One, and the difference lies in the specific process parameters used in each step. The detailed process parameter settings can be referred to Table One.

[0167] Among them, Comparative Example One and Example One form a first control group, Comparative Example Two and Example Two form a second control group, and Comparative Example Three and Example Three form a third control group.

[0168] Table One

[0169]

[0170] The related parameters of the split cells obtained by the preparation methods of Example One to Example Three of the present disclosure, and the related parameters of the split cells obtained by the preparation methods of Comparative Example One to Comparative Example Three of the present disclosure are shown in Table Two.

[0171] Table Two

[0172]

[0173] Referring to Table Two, in the first control group, the cell efficiency of the solar cell corresponding to Example One is 27.188%, and the cell efficiency of the solar cell corresponding to Comparative Example One is 27.109%, which is increased by 0.079%; in the second control group, the cell efficiency of the solar cell corresponding to Example Two is 27.174%, and the cell efficiency of the solar cell corresponding to Comparative Example Two is 27.130%, which is increased by 0.044%; in the third control group, the cell efficiency of the solar cell corresponding to Example Three is 27.161%, and the cell efficiency of the solar cell corresponding to Comparative Example Three is 27.102%, which is increased by 0.059%. Compared with the solar cell without amorphous carbon film, the cell efficiency, open circuit voltage and fill factor of the solar cell provided by the present disclosure with amorphous carbon film are all improved.

[0174] The present disclosure further provides a photovoltaic module, which refers to Figure 21 and Figure 22As shown, the solar cell module comprises: a battery string, which is connected by a plurality of solar cells 6 provided by any of the preceding embodiments or formed by the preparation method of any of the preceding embodiments; an encapsulation film 8 for covering the surface of the battery string; and a cover plate 9 for covering the surface of the encapsulation film 8 away from the battery string.

[0175] It should be noted that the solar cells are electrically connected to form a plurality of battery strings, and the plurality of battery strings are electrically connected in series and / or parallel. Based on the solar cell comprising a split cell formed by splitting a whole solar cell, the current drop of the split cell can improve the power loss of the photovoltaic module, thereby improving the photoelectric conversion efficiency of the photovoltaic module.

[0176] In one or more embodiments, referring to Figure 21 As shown, the plurality of battery strings can be electrically connected by the conductive strips 7. Figure 21 Only the positional relationship between the solar cells is shown, i.e., the arrangement direction of the electrodes with the same polarity of the cell pieces is the same, or in other words, each cell piece has the electrodes with the positive polarity arranged towards the same side, so that the conductive strips connect the different sides of two adjacent cell pieces, respectively. In some embodiments, the cell pieces can also be arranged according to the electrodes with different polarities towards the same side, i.e., the electrodes of the adjacent cell pieces are sequentially arranged in the order of the first polarity, the second polarity, and the first polarity, respectively, and then the conductive strips connect two adjacent cell pieces on the same side.

[0177] In one or more embodiments, no spacing is provided between the cell pieces, i.e., the cell pieces overlap each other.

[0178] In one or more embodiments, the encapsulating film includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front or back sides of the solar cell, and the second encapsulating layer covers the other of the front or back sides of the solar cell. Specifically, at least one of the first or second encapsulating layer may be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyethylene octene elastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first or second encapsulating layer may also be an EP film, EPE film, or PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film; EPE film refers to a co-extruded film formed by sequentially stacking EVA film, POE film, and EVA film; and PVP film refers to a co-extruded film formed by stacking POE film, EVA film, and POE film. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0179] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After lamination, the photovoltaic module no longer has the concept of a first encapsulation layer and a second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film.

[0180] In one or more embodiments, the cover plate can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate facing the encapsulating film can be an uneven surface, thereby increasing the utilization rate of incident light. The cover plate includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0181] In one or more embodiments, reference is made to Figure 21 As shown, the solar cells 6 in the battery string are arranged along the direction U, and the main grids of two adjacent solar cells 6 in the battery string are staggered in the direction V. For photovoltaic modules, by setting the main grids of two adjacent solar cells 6 in the battery string to be staggered in the direction V, the photovoltaic modules can be tested at different potentials, thereby improving the reliability of the test results.

[0182] Those skilled in the art can understand that the above-mentioned embodiments are specific embodiments for realizing the present disclosure, and in actual applications, various changes can be made in form and details without departing from the spirit and scope of the present disclosure. Any person skilled in the art can make various modifications and changes without departing from the spirit and scope of the present disclosure.

Claims

1. A solar cell, characterized in that, include: The segmented battery includes a first side and a second side disposed along the thickness direction, and a third side connecting the first side and the second side. The third side includes a segmented side, and at least one end of the segmented side near the first side and / or the second side is provided with a groove, and the groove is provided with an amorphous carbon film. A passivation layer covering the amorphous carbon film and the portion of the segmented side where the amorphous carbon film is not disposed; The segmented battery further includes a substrate and a first film layer structure; the substrate includes a front side and a back side disposed along the thickness direction of the substrate, and a side side connecting the front side and the back side; the first film layer structure is disposed on the back side; the first side is the side where the front side is located, the second side is the side of the first film layer structure away from the substrate, and the segmented side is the integral formed by the side of the first film layer structure near the passivation layer and the side side in contact with the passivation layer; the groove is formed between the side of the first film layer structure near the passivation layer and the passivation layer.

2. The solar cell according to claim 1, characterized in that, The surface of the first film structure facing away from the substrate is flush with the surface of the amorphous carbon film facing away from the substrate.

3. The solar cell according to claim 2, characterized in that, The surface of the first film layer structure near the substrate is flush with the surface of the amorphous carbon film near the substrate.

4. The solar cell according to claim 1, characterized in that, The thickness of the first film structure is greater than or equal to the thickness of the amorphous carbon film.

5. The solar cell according to claim 1, characterized in that, The thickness of the amorphous carbon film is 20µm to 30µm.

6. The solar cell according to claim 1, characterized in that, The thickness of the amorphous carbon film accounts for 10% to 30% of the thickness of the sectional battery.

7. The solar cell according to any one of claims 1 to 6, characterized in that, The amorphous carbon film has a distance of 50um to 125um along the first direction, which is perpendicular to the plane where the passivation layer is located.

8. The solar cell according to claim 7, characterized in that, The ratio of the distance of the amorphous carbon film along the first direction to the distance of the segmented battery along the first direction is 0.03% to 0.08%.

9. The solar cell according to claim 7, characterized in that, The ratio of the distance of the amorphous carbon film along the second direction to the distance of the segmented battery along the second direction is 2% to 30%, wherein the second direction is perpendicular to the first direction.

10. The solar cell according to claim 1, characterized in that, The amorphous carbon film comprises amorphous carbon particles and glass particles.

11. A method for preparing a solar cell, characterized in that, The method for preparing the solar cell according to any one of claims 1 to 10 includes: Provide a whole solar cell; wherein the whole solar cell includes a region to be segmented; A cutting groove is formed at at least one end of the region to be segmented using a first laser device; An amorphous carbon film is formed in the region to be divided, wherein the amorphous carbon film fills the cutting groove; The amorphous carbon film is cut using a second laser device, wherein the width of the amorphous carbon film is greater than the laser cutting width of the second laser device; The region to be divided is separated so that the entire solar cell is split along the cutting direction of the amorphous carbon film to form at least two segmented cells; wherein, the segmented cell includes a first side and a second side arranged along the thickness direction, and a third side connecting the first side and the second side, the third side including a dividing side, and at least one end of the dividing side near the first side and / or the second side is provided with a groove, the groove being provided with an amorphous carbon film; A passivation layer is formed, which covers the amorphous carbon film and the portion of the segmented side where the amorphous carbon film is not disposed.

12. The method for preparing a solar cell according to claim 11, characterized in that, The process of forming an amorphous carbon film in the region to be segmented includes: Amorphous carbon paste is printed in the area to be segmented; The amorphous carbon slurry is dried.

13. The method for preparing a solar cell according to claim 11, characterized in that, The cutting depth of the second laser device is less than the thickness of the amorphous carbon film.

14. A photovoltaic module, characterized in that, include: A battery string is formed by connecting multiple solar cells as described in any one of claims 1 to 10, or by connecting multiple solar cells formed by the preparation method as described in any one of claims 11 to 13; An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

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