Solar cell and method of manufacture, sliced cell, stacked cell and photovoltaic module

Abstract

This application relates to solar cells and their fabrication methods, sliced ​​solar cells, tandem solar cells, and photovoltaic modules, comprising: a substrate having a first surface and a second surface disposed opposite each other in the thickness direction, the substrate including an emitter layer and a body layer along the direction from the first surface to the second surface; a first groove structure disposed on the first surface of the substrate, the first groove structure penetrating the emitter layer and extending to the body layer along the thickness direction, the first groove structure including a first bottom surface recessed inward relative to the first surface and a first side surface extending obliquely from the first surface and connected to the first bottom surface; a passivation layer covering the first surface, the first bottom surface, and the first side surface; and a second groove structure disposed on the first surface or the second surface of the substrate, the projection of the second groove structure in the thickness direction located within the projection of the first bottom surface in the thickness direction. This application can improve the fill factor and conversion efficiency of the solar cell.

Description

Technical Field

[0001] This application relates to the field of solar cells, and in particular to a solar cell and its preparation method, a sliced ​​cell, a tandem cell, and a photovoltaic module. Background Technology

[0002] With the development of the photovoltaic industry, the conversion efficiency of solar cells is constantly improving. To further increase the power of photovoltaic modules, half-cell, or even three- or four-cell cell structures are generally adopted to reduce the current of a single cell, thereby reducing the total series resistance loss of the module. To fully utilize production capacity, the laser slicing step is generally placed after all the manufacturing processes of the whole solar cell. However, the direct action of the laser on the emitter during slicing causes high edge damage, and the sliced ​​cells formed after slicing lack a passivation layer to protect the emitter, resulting in a decrease in the fill factor (FF) and conversion efficiency of the cell. Summary of the Invention

[0003] This application provides a solar cell and its preparation method, a sliced ​​cell, a tandem cell, and a photovoltaic module, which can improve the fill factor and conversion efficiency of the cell.

[0004] In a first aspect, the solar cell provided in the embodiments of this application includes: A substrate having a first surface and a second surface disposed opposite each other in the thickness direction, the substrate including an emitter layer and a body layer along the direction from the first surface to the second surface; A first groove structure is disposed on a first surface of the substrate. The first groove structure penetrates the emitter layer along the thickness direction and extends to the body layer. The first groove structure includes a first bottom surface that is recessed inward relative to the first surface and a first side surface that extends obliquely from the first surface and is connected to the first bottom surface. A passivation layer covers the first surface, the first bottom surface, and the first side surface; and A second groove structure is provided on the first or second surface of the substrate, and the projection of the second groove structure in the thickness direction is located within the projection of the first bottom surface in the thickness direction.

[0005] In some embodiments, the first groove structure extends through the substrate along a first direction, which is perpendicular to the thickness direction.

[0006] In some embodiments, the depth of the first groove structure is 1 μm to 10 μm; and / or, The width of the first groove structure is 200 μm to 1000 μm; and / or, The slope of the first groove structure is 40° to 80°.

[0007] In some embodiments, the second groove structure extends through the substrate along a first direction, which is perpendicular to the thickness direction.

[0008] In some embodiments, the first groove structure and the second groove structure are provided in a one-to-one correspondence, and the second groove structure is provided at one end of the substrate in the first direction; or, one first groove structure is provided in a corresponding manner with two second groove structures, one of the second groove structures is provided at one end of the substrate in the first direction, and the other second groove structure is provided at the other end of the substrate in the first direction; Wherein, the first direction is perpendicular to the thickness direction.

[0009] In some embodiments, the length of the second groove structure in the first direction is 1 mm to 2 mm.

[0010] In some embodiments, the depth of the first groove structure is greater than the depth of the second groove structure; and / or, the width of the first groove structure is greater than the width of the second groove structure.

[0011] In some embodiments, the projection of the first groove structure in the thickness direction is axially symmetrical about a first virtual straight line, and the projection of the second groove structure in the thickness direction is axially symmetrical about the first virtual straight line, wherein the first virtual straight line is perpendicular to the thickness direction.

[0012] In some embodiments, the depth of the second groove structure is 1 μm to 2 μm; and / or, The width of the second groove structure is 50 μm to 150 μm; and / or, The slope of the second groove structure is 80° to 90°.

[0013] In some embodiments, the second groove structure includes a second bottom surface recessed into the body layer relative to the first bottom surface, and a second side surface connecting the second bottom surface and the passivation layer on a side surface away from the substrate.

[0014] In some embodiments, the second groove structure includes a second bottom surface recessed into the body layer relative to the second surface and a second side surface connecting the second bottom surface and the second surface.

[0015] Secondly, the method for preparing a solar cell provided in this application is used to prepare the solar cell provided in any of the above embodiments, the method comprising: A substrate is provided, the substrate having a first surface and a second surface disposed opposite to each other in the thickness direction, the substrate including an emitter layer and a body layer along the direction from the first surface to the second surface; The emitter layer and part of the body layer in the predetermined region of the substrate are removed to form a first groove structure; A passivation layer is formed covering the first surface and the surface of the first groove structure; A portion of the thickness of the body layer is removed to form a second groove structure.

[0016] Thirdly, the sliced ​​battery provided in this application embodiment is obtained by cutting the solar cell provided in any of the above embodiments, or by cutting the solar cell prepared by the method of preparing the solar cell provided in any of the above embodiments.

[0017] Fourthly, the stacked battery provided in the embodiments of this application includes: Top cell, which can be a perovskite cell, cadmium telluride solar cell, copper indium gallium selenide solar cell, or gallium arsenide solar cell; Intermediate connecting layer; and The base cell is a solar cell provided in any of the above embodiments, or a solar cell prepared by the method for preparing a solar cell provided in any of the above embodiments, or a sliced ​​cell provided in any of the above embodiments; The top battery, the intermediate connecting layer, and the bottom battery are stacked and connected.

[0018] Fifthly, the photovoltaic module provided in the embodiments of this application includes the solar cell provided in any of the above embodiments, or the solar cell prepared by the preparation method of the solar cell provided in any of the above embodiments, or the sliced ​​cell provided in any of the above embodiments, or the stacked cell provided in any of the above embodiments.

[0019] Compared with the prior art, the beneficial effects of the embodiments of this application are as follows: the solar cell and its fabrication method, the sliced ​​cell, the tandem cell, and the photovoltaic module have a first groove structure and a second groove structure on the substrate. The first groove structure penetrates the emitter layer and extends to the body layer. The surfaces (first bottom surface and first side surface) of the first groove structure are completely covered by a passivation layer, thereby achieving no emitter polarization and effective surface passivation in this region. Furthermore, the inclined first side surface, compared to the vertical first side surface, reduces local stress concentration, enhances the mechanical stability of the first groove structure, and avoids cracks during subsequent slab or module packaging. Because it reduces the risk of cracking and protects the integrity of the structure, the inclined first side surface helps maintain the continuity of the carrier transport channel, thereby improving conversion efficiency. The second groove structure is aligned with the bottom projection of the first groove structure in the thickness direction. During cell slicing, slicing can be performed along the paths guided by the first and second groove structures. This not only provides clear stress extension guidance for slicing, making it faster and more precise, but also minimizes damage to the passivation layer and avoids direct damage to the emitter layer during slicing. Furthermore, the sides of the sliced ​​cells still have a passivation layer protecting the emitter layer, thereby improving the fill factor (FF) and conversion efficiency of the cells. In addition, the positions of the first and second groove structures can be adjusted according to actual needs, allowing solar cells to adapt to various cell layout requirements such as half-cell, three-cell, or four-cell slicing. This improves performance, increases flexibility, and reduces manufacturing costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the solar cell structure according to an embodiment of this application.

[0021] Figure 2 for Figure 1 A schematic diagram of the partial structure of the front area of ​​the AA section.

[0022] Figure 3 for Figure 2 The diagram shows the structure after it has been divided.

[0023] Figure 4 for Figure 2 A schematic diagram of the back area structure corresponding to the front area shown.

[0024] Figure 5 for Figure 4 The diagram shows the structure after it has been divided.

[0025] Figure 6 This is a partial structural schematic diagram of a solar cell according to an embodiment of this application.

[0026] Figure 7 for Figure 6 The diagram shows the structure after it has been divided.

[0027] Figure 8 This is a partial structural diagram of the front area of ​​a solar cell according to an embodiment of this application.

[0028] Figure 9 for Figure 8 The diagram shows the structure after it has been divided.

[0029] Figure 10 for Figure 8 A schematic diagram of the back area structure corresponding to the front area shown.

[0030] Figure 11 for Figure 10 The diagram shows the structure after it has been divided.

[0031] Figure 12 This is a partial structural schematic diagram of a solar cell according to an embodiment of this application.

[0032] Figure 13 for Figure 12 The diagram shows the structure after it has been divided.

[0033] Figure 14 for Figure 12 Another perspective illustration.

[0034] Figure 15 for Figure 13 Another perspective illustration. Detailed Implementation

[0035] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0036] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0038] Please refer to Figures 1 to 15This application embodiment of the solar cell 100 includes a substrate 110, a first groove structure 111, a second groove structure 112, and a passivation layer 120. The substrate 110 has a first surface 110a and a second surface 110b disposed opposite each other in the thickness direction. The substrate 110 includes an emitter layer 113 and a body layer 114, which are sequentially disposed along the direction from the first surface 110a to the second surface 110b. The first groove structure 111 is disposed on the first surface 110a of the substrate 110. The first groove structure 111 penetrates the emitter layer 113 and extends to the body layer 114 in the thickness direction, that is, there is no emitter layer 113 below the first groove structure 111. The first groove structure 111 includes a first bottom surface 1111 and a first side surface 1112. The first bottom surface 1111 is recessed inward relative to the first surface 110a, and the first side surface 1112 extends obliquely from the first surface 110a and connects to the first bottom surface 1111. The second groove structure 112 is disposed on the first surface 110a of the substrate 110 or on the second surface 110b of the substrate 110, and the projection of the second groove structure 112 in the thickness direction is located within the projection of the first bottom surface 1111 in the thickness direction. The passivation layer 120 covers the first surface 110a, the first bottom surface 1111, and the first side surface 1112.

[0039] In this embodiment, the substrate 110 is provided with a first groove structure 111 and a second groove structure 112. The first groove structure 111 penetrates the emitter layer 113 and extends to the body layer 114. The surfaces of the first groove structure 111 (first bottom surface 1111 and first side surface 1112) are completely covered by a passivation layer 120, thereby achieving no emitter polarization and effective surface passivation in this region. Furthermore, the inclined first side surface 1112, compared to a vertical first side surface, reduces local stress concentration, enhances the mechanical stability of the first groove structure 111, and prevents cracks from forming during subsequent slab or component packaging. By reducing the risk of cracking and protecting the structural integrity, the inclined first side surface 1112 helps maintain the continuity of the carrier transport channel, thereby improving conversion efficiency. The projection of the second groove structure 112 in the thickness direction lies within the projection of the first bottom surface 1111 of the first groove structure 111 in the thickness direction. During cell slicing, slicing can be performed along the path guided by the first groove structure 111 and the second groove structure 112. This not only provides clear stress extension guidance for slicing, making it faster and more precise, but also minimizes damage to the passivation layer 120 and avoids direct damage to the emitter layer 113 during slicing. Furthermore, the sides of the sliced ​​cells 200 still have the passivation layer 120 protecting the emitter layer 113, thereby improving the fill factor (FF) and conversion efficiency of the cells. In addition, the positions of the first groove structure 111 and the second groove structure 112 can be adjusted according to actual needs, allowing the solar cell 100 to adapt to various cell slicing requirements such as half-cell, three-cell, or four-cell configurations. This improves performance, increases flexibility, and reduces manufacturing costs.

[0040] As an example, the surface of the emitter layer 113 away from the body layer 114 is a first surface 110a, and the surface of the body layer 114 away from the emitter layer 113 is a second surface 110b. In some examples, the first surface 110a is the front side of the substrate 110, and the second surface 110b is the back side of the substrate 110.

[0041] In some implementation methods, please refer to Figure 2 and Figure 6The second groove structure 112 is formed on the side of the first surface 110a of the substrate 110. More specifically, the second groove structure 112 is formed on the first bottom surface 1111 of the first groove structure 111. The second groove structure 112 includes a second bottom surface 1121 and a second side surface 1122. The second bottom surface 1121 is recessed into the substrate 110 (body layer 114) relative to the first bottom surface 1111. The second side surface 1122 connects the second bottom surface 1121 and the side surface of the passivation layer 120 away from the substrate 110. That is, the passivation layer 120 does not cover the second groove structure 112. As an example, the passivation layer 120 can be formed first, and then the second groove structure 112 can be formed.

[0042] In this embodiment, the first groove structure 111 is mainly used for emitter isolation and edge passivation, while the second groove structure 112 is mainly used to construct a geometrically clear mechanical guiding structure in the electrically isolated area without passivation layer interference. This ensures that the shear stress can be directly applied to the body layer 114 of the substrate 110 through the second groove structure 112, thereby improving crack accuracy and propagation speed. Moreover, it minimizes the damage to the passivation layer 120 during the shearing process and ensures that the passivation interface formed in the first groove structure 111 is completely preserved after slicing.

[0043] In some embodiments, the passivation layer 120 can be a single-layer structure or a stacked structure, and the material used to prepare the passivation layer 120 can be one or more of the following: silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, titanium oxide, hafnium oxide, or aluminum oxide. As an example, the passivation layer 120 is an aluminum oxide layer.

[0044] In some embodiments, the solar cell 100 further includes a first antireflection layer 130, which is formed on the surface of the passivation layer 120 away from the substrate 110. As an example, the first antireflection layer 130 can be made of one or more of silicon nitride or silicon oxynitride. In some examples, the first antireflection layer 130 is silicon nitride. In this embodiment, the first antireflection layer 130 can reduce the reflection loss of incident light on the cell surface through optical interference effects, thereby enhancing the photocurrent. Simultaneously, the dense thin-film structure of the first antireflection layer 130 can effectively block external moisture and contaminants from eroding the passivation layer 120, preventing passivation performance degradation, and providing a certain degree of mechanical protection for the cell surface. Since the passivation layer 120 covers the surface of the first groove structure 111 and the first antireflection layer 130 covers the surface of the passivation layer 120, the first antireflection layer 130 also completely covers the first groove structure 111. When the first antireflection layer 130 covers the area that has been passivated at the edge by the first groove structure 111, the performance of the battery after slab formation can be more effectively ensured.

[0045] As one implementation method, please refer to Figure 2 and Figure 6 When the second groove structure 112 is formed on the side of the first surface 110a of the substrate 110, the first antireflective layer 130 does not cover the second groove structure 112. The second side surface 1122 of the second groove structure 112 extends from the surface of the first antireflective layer 130 away from the passivation layer 120 to the second bottom surface 1121. As an example, the first antireflective layer 130 can be formed first, and then the second groove structure 112 can be formed. This embodiment provides a mechanical interface without film layer interference for slab segmentation, thereby allowing the cutting stress to act directly and unimpeded on the body layer 114, improving the control accuracy of crack initiation and propagation, and achieving more efficient low-damage slab segmentation while ensuring the overall reliability of the battery.

[0046] In some implementation methods, please refer to Figure 10 and Figure 14 The second groove structure 112 is formed on the side of the substrate 110 where the second surface 110b is located. More specifically, the second groove structure 112 includes a second bottom surface 1121 and a second side surface 1122. The second bottom surface 1121 is recessed into the substrate 110 (body layer 114) relative to the second surface 110b, and the second side surface 1122 connects the second surface 110b and the second bottom surface 1121. Since the second groove structure 112 is formed on the second surface 110b (back side) of the substrate 110, the formation process of the second groove structure 112 does not affect the front emitter layer 113, passivation layer 120, and first antireflection layer 130, thereby avoiding potential damage to the front photoelectric performance area.

[0047] In some implementation methods, please refer to Figure 10 The solar cell 100 further includes a tunneling oxide layer 140, a doped polycrystalline silicon layer 150, and a second antireflection layer 160. The tunneling oxide layer 140 is formed on the second surface 110b of the substrate 110, the doped polycrystalline silicon layer 150 is formed on the side of the tunneling oxide layer 140 away from the substrate 110, and the second antireflection layer 160 is formed on the side of the doped polycrystalline silicon layer 150 away from the tunneling oxide layer 140. In this embodiment, the tunneling oxide layer 140 can suppress carrier recombination on the surface of the substrate 110, the doped polycrystalline silicon layer 150 achieves efficient selective collection of carriers by modulating the energy band, reducing contact resistance, and the second antireflection layer 160 can reduce optical reflection loss on the back side of the substrate 110. The tunneling oxide layer 140, the doped polycrystalline silicon layer 150, and the second antireflection layer 160 work synergistically to improve the open-circuit voltage, short-circuit current, and fill factor of the cell, thereby further improving the photoelectric conversion efficiency of the cell.

[0048] As one implementation method, please refer to Figure 10When the second groove structure 112 is formed on the second surface 110b of the substrate 110, the tunneling oxide layer 140, the doped polysilicon layer 150, and the second antireflection layer 160 do not cover the second groove structure 112. That is, the second side surface 1122 extends from the surface of the second antireflection layer 160 away from the doped polysilicon layer 150 to the second bottom surface 1121. As an example, the tunneling oxide layer 140, the doped polysilicon layer 150, and the second antireflection layer 160 can be formed sequentially first, and then the second groove structure 112 can be formed.

[0049] In this embodiment, please refer to Figure 10 The second bottom surface 1121 of the second groove structure 112 is defined by the body layer 114 of the base, that is, part of the body layer 114 is exposed through the second groove structure 112, which avoids the delamination, tearing or stress dispersion problems that may be caused by the multilayer film during the slitting process, so that the slitting stress can be directly applied to the body layer 114, thereby ensuring that the integrity and functionality of the passivation contact structure on the back of the battery are not damaged while achieving efficient and low-loss slitting.

[0050] In some implementation methods, please refer to Figure 2 , Figure 6 , Figure 8 and Figure 12 The first groove structure 111 penetrates the substrate 110 along a first direction, which is the length direction of the first groove structure 111 and perpendicular to the thickness direction. In this embodiment, the first groove structure 111 completely penetrates the substrate 110 along a direction parallel to the battery surface (i.e., perpendicular to the thickness direction), physically blocking the extension of the emitter layer 113 to the slab region. This confines the subsequent slab path within the body layer 114 region without an emitter. Simultaneously, all inner surfaces of the first groove structure 111 (the first bottom surface 1111 and the first side surface 1112) have been covered with a passivation layer 120 before slab slab formation. Therefore, the slitting action during slab formation will act entirely on the pre-prepared and passivated dedicated separation area (within the first groove structure 111), thereby avoiding direct damage to the emitter layer 113 during slab formation and improving the passivation integrity of the slab side.

[0051] In some embodiments, the depth H1 of the first groove structure 111 is 1 μm to 10 μm. For example, the depth H1 of the first groove structure 111 can be, but is not limited to, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, etc. Here, the depth H1 of the first groove structure 111 refers to the distance from the first bottom surface 1111 of the first groove structure 111 to the first surface 110a. Since the passivation layer 120 and the first antireflection layer 130 are thin films uniformly covering the first surface 110a and the surface of the first groove structure 111, the depth H1 of the first groove structure 111 can also be considered as the distance between the first antireflection layer 130 on the first surface 110a and the first antireflection layer 130 on the first bottom surface 1111 of the first groove structure 111. In this embodiment, the first groove structure 111 with a depth H1 of 1μm to 10μm can ensure that the bottom of the first groove structure 111 extends into the body layer 114, thereby providing an emitter-free dividing interface for slab division. At the same time, it avoids excessive etching damage to the body layer 114, so that the solar cell 100 has sufficient structural stability and fracture resistance after the first groove structure 111 is opened and before the second groove structure 112 is opened, thereby effectively preventing the solar cell 100 from breaking accidentally during the fabrication process.

[0052] In some embodiments, the width W1 of the first groove structure 111 in the thickness direction is 200μm to 1000μm. This ensures that the cutting tool (such as a laser beam) is completely contained within the first groove structure 111 during the slicing process, thereby effectively isolating the cutting stress and heat-affected zone and preventing the cutting tool from causing accidental damage to the emitters and passivation layer 120 of the functional areas on both sides. At the same time, this width accounts for a small proportion of the overall power area of ​​the battery, maintaining the initial conversion efficiency of the battery as much as possible while ensuring slicing reliability and yield. As an example, the width W1 of the first groove structure 111 can be, but is not limited to, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, or 1000μm, etc.

[0053] In one implementation, the width direction of the first groove structure 111 is the second direction, and the second direction, the first direction, and the thickness direction are perpendicular to each other.

[0054] In some embodiments, the slope θ1 of the first groove structure 111 is 40° to 80°, which is more conducive to the continuous and uniform deposition of the subsequent passivation layer 120 on the first side surface 1112, ensuring the formation of complete surface passivation and thus effectively suppressing carrier recombination. Simultaneously, the inclined first side surface 1112, compared to the vertical first side surface, reduces local stress concentration, enhances the mechanical stability of the first groove structure 111, and avoids cracking during subsequent dicing or component packaging. Furthermore, it prevents excessive effective area loss and increased fabrication difficulty due to excessively large slot openings in the first groove structure 111. As one embodiment, the slope θ1 of the first groove structure 111 can be, but is not limited to, 40°, 50°, 60°, 70°, or 80°, etc. For example, the slope θ1 of the first groove structure 111 refers to the angle between the first side surface 1112 of the first groove structure 111 and the first virtual plane, where the first virtual plane refers to the plane containing the first bottom surface 1111.

[0055] In some implementation methods, please refer to Figure 2 and Figure 10 The second groove structure 112 penetrates the substrate 110 along the first direction. The second groove structure 112 provides a preset mechanical weakening surface that penetrates the entire substrate 110 along the first direction for the sheeting process, so that the shearing stress can be effectively directionally extended and released within the preset mechanical weakening surface, effectively reducing the risk of random cracks, fragments and hidden damage during the sheeting process, and improving the sheeting yield.

[0056] In other implementations, please refer to Figure 6 and Figure 14 , Figure 6 and Figure 14 Only a partial structure of one end of the solar cell 100 in the first direction is shown. Please refer to... Figure 6 and Figure 14 The second groove structure 112 does not penetrate the substrate 110 along the first direction. The second groove structure 112 is formed at the end of the substrate 110 in the first direction, providing a defined starting point and / or ending point for dicing and a stress concentration guidance area, while ensuring the overall structural strength of the substrate 110 and the integrity of the passivation layer 120 and the first anti-reflection layer 130 (when the second groove structure 112 is on the first surface 110a) or the integrity of the tunnel oxide layer 140, the doped polysilicon layer 150 and the second anti-reflection layer 160 (when the second groove structure 112 is on the second surface 110b), thereby achieving controllable and low-damage dicing, balancing process reliability and structural integrity.

[0057] In one implementation, the first groove structure 111 and the second groove structure 112 are arranged in a one-to-one correspondence, with the second groove structure 112 disposed at one end of the substrate 110 in the first direction. During slicing, the second groove structure 112 can serve as the starting position for slicing, allowing the slicing process to proceed along a preset path within the first groove structure 111. This helps control the crack propagation direction, reduces path deviation during slicing, and minimizes the generation of unexpected branch cracks. Moreover, the structure is simple, reducing process complexity while ensuring slicing accuracy. It also minimizes damage to the passivation layer 120 and the first antireflection layer 130 (when the second groove structure 112 is on the first surface 110a) or minimizes damage to the tunneling oxide layer 140, the doped polysilicon layer 150, and the second antireflection layer 160 (when the second groove structure 112 is on the second surface 110b).

[0058] In one implementation, a first groove structure 111 and two second groove structures 112 are correspondingly arranged, with one second groove structure 112 disposed at one end of the substrate 110 in a first direction and the other second groove structure 112 disposed at the other end of the substrate 110 in the first direction. During slicing, one second groove structure 112 can serve as the starting position for slicing, and the other second groove structure 112 can serve as the ending position for slicing. Laser or mechanical stress can enter from the second groove structure 112 at one end and advance along a preset path within the first groove structure 111 until it reaches the second groove structure 112 at the other end. This not only effectively constrains the crack propagation range, avoiding excessive extension or deviation, but also effectively reduces the risk of damage such as edge chipping, further ensuring slicing accuracy.

[0059] As an example, please refer to Figure 6 and Figure 14 When the second groove structure 112 does not penetrate the substrate 110 along the first direction, the length L2 of the second groove structure 112 in the first direction is 1mm to 2mm. This ensures the formation of an effective stress concentration guiding structure while minimizing the weakening of the overall mechanical strength of the substrate 110 by the second groove structure 112. For example, the length L2 of the second groove structure 112 in the first direction can be, but is not limited to, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, or 2mm, etc.

[0060] In some embodiments, the depth H1 of the first groove structure 111 is greater than the depth H2 of the second groove structure 112 in the thickness direction. The deeper first groove structure 111 ensures that the bottom surface of the first groove structure 111 and the emitter layer 113 below it are completely removed, thereby ensuring the electrical performance of the battery after slab separation. The shallower second groove structure 112 can not only effectively guide stress, but also avoid excessive weakening of the substrate 110, thus balancing the accuracy of slab separation guidance with the mechanical integrity of the substrate.

[0061] In some embodiments, in the second direction, the width W1 of the first groove structure 111 is greater than the width W2 of the second groove structure 112. The wider first groove structure 111 provides sufficient operating space and process tolerance for the dicing tool (such as a laser beam), reduces the risk of damage caused by misalignment, and provides more space for the deposition of the passivation layer 120, which is conducive to achieving more complete and uniform edge passivation protection. It can also ensure that the emitter layers 113 on both sides are not damaged when dicing along the second groove structure 112. The narrower second groove structure 112 helps to generate a more significant stress concentration effect locally, thereby achieving precise crack initiation and convergence with lower cutting energy. It also reduces the occupation of the effective area of ​​the battery, minimizing damage to the passivation layer 120 and the first antireflection layer 130 (when the second groove structure 112 is on the first surface 110a) or minimizing damage to the tunneling oxide layer 140, the doped polysilicon layer 150 and the second antireflection layer 160 (when the second groove structure 112 is on the second surface 110b).

[0062] In some embodiments, the projection of the first groove structure 111 in the thickness direction is axially symmetrical about the first virtual straight line 300, and the projection of the second groove structure 112 in the thickness direction is axially symmetrical about the first virtual straight line 300, which is parallel to the first direction. That is, the first groove structure 111 and the second groove structure 112 are symmetrical about the same axis of symmetry. During the segmentation process, the cutting stress is uniformly transmitted and released to both sides, allowing the crack to propagate along a predetermined path, thus avoiding problems such as unilateral stress concentration, path offset, or cross-sectional tilt caused by structural asymmetry.

[0063] In some embodiments, the depth H2 of the second groove structure 112 in the thickness direction is 1 μm to 2 μm, thereby forming a mechanically weakening line on the substrate 110 sufficient to induce stress concentration, while maintaining the overall structural strength of the substrate as much as possible. As one embodiment, the depth H2 of the second groove structure 112 can be, but is not limited to, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, or 2 μm, etc. As an example, when the second groove structure 112 is disposed on the first surface 110a and the solar cell 100 includes a passivation layer 120 and a first antireflection layer 130, that is, when the second groove structure 112 is formed on the first bottom surface 1111 of the first groove structure 111 and the solar cell 100 includes a passivation layer 120 and a first antireflection layer 130, the depth H2 of the second groove structure 112 refers to the distance in the thickness direction between the second bottom surface 1121 of the second groove structure 112 and the side surface of the first antireflection layer 130 away from the passivation layer 120. When the second groove structure 112 is disposed on the second surface 110b and the solar cell 100 includes a tunneling oxide layer 140, a doped polycrystalline silicon layer 150 and a second antireflection layer 160, the depth H2 of the second groove structure 112 refers to the distance in the thickness direction between the second bottom surface 1121 of the second groove structure 112 and the side surface of the second antireflection layer 160 away from the doped polycrystalline silicon layer 150.

[0064] In some embodiments, the width W2 of the second groove structure 112 in the second direction is 50 μm to 150 μm. A narrower width helps to create a higher energy density locally, prompting the crack to precisely initiate and extend along a predetermined path during flaking. This size range also provides sufficient alignment tolerance for process implementation. As one embodiment, the width W2 of the second groove structure 112 can be, but is not limited to, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, or 150 μm, etc.

[0065] In some embodiments, the slope θ2 of the second groove structure 112 is 80° to 90°. The vertical and nearly vertical second side surface 1122 can generate an effective stress concentration effect at the bottom corner of the second groove structure 112, which is beneficial for triggering and controlling cracks with lower energy during segmentation. As one embodiment, the slope θ2 of the second groove structure 112 can be, but is not limited to, 80°, 81°, 82°, 83°, 84°, 85°, 86°, 87°, 88°, 89°, or 90°, etc. For example, the slope θ2 of the second groove structure 112 refers to the angle between the second side surface 1122 of the second groove structure 112 and the second virtual plane, where the second virtual plane refers to the plane containing the second bottom surface 1121.

[0066] In some implementation methods, please refer to Figure 2 , Figure 6 , Figure 8 and Figure 12 The first surface 110a has a pyramidal textured surface. This textured surface can reflect and scatter incident light multiple times, extending the propagation path of photons inside the cell and increasing the probability of light absorption. Simultaneously, the pyramidal textured surface also helps reduce surface reflectivity, further enhancing the cell's utilization of broadband, multi-angle incident light. Furthermore, a suitable textured surface morphology facilitates the uniform coverage of the subsequent passivation layer 120 and the first antireflection layer 130, maintaining good surface passivation quality while improving optical performance.

[0067] In some embodiments, the solar cell 100 further includes a first electrode 170 and a second electrode 180. The first electrode 170 passes through the first antireflection layer 130 and the passivation layer 120 in the thickness direction of the substrate 110 and is connected to the emitter layer 113. The second electrode 180 extends through the second antireflection layer 160 in the thickness direction of the substrate 110 and is connected to the doped polycrystalline silicon layer 150.

[0068] As an example, the solar cell 100 in this embodiment can be a TOPCon (Tunnel Oxide Passivated Contact) solar cell. It should be noted that in other embodiments, the solar cell can also be other types of solar cells, which can be set according to actual conditions, and will not be elaborated here.

[0069] The method for preparing a solar cell according to the embodiments of this application is used to prepare the solar cell 100 provided in any of the above embodiments.

[0070] In this embodiment, the substrate 110 is provided with a first groove structure 111 and a second groove structure 112. The first groove structure 111 penetrates the emitter layer 113 and extends to the body layer 114. The surfaces of the first groove structure 111 (first bottom surface 1111 and first side surface 1112) are completely covered by a passivation layer 120, thereby achieving no emitter polarization and effective surface passivation in this region. Furthermore, the inclined first side surface 1112, compared to a vertical first side surface, reduces local stress concentration, enhances the mechanical stability of the first groove structure 111, and prevents cracks from forming during subsequent slab or component packaging. By reducing the risk of cracking and protecting the structural integrity, the inclined first side surface 1112 helps maintain the continuity of the carrier transport channel, thereby improving conversion efficiency. The second groove structure 112 is aligned with the bottom projection of the first groove structure 111 in the thickness direction. During cell slicing, slicing can be performed along the path guided by the first groove structure 111 and the second groove structure 112. This not only provides clear stress extension guidance for slicing, making slicing faster and more accurate, but also minimizes damage to the passivation layer 120 and avoids direct damage to the emitter layer 113 during slicing. Furthermore, the sides of the sliced ​​cells 200 still have the passivation layer 120 protecting the emitter layer 113, thereby improving the fill factor (FF) and conversion efficiency of the cells. In addition, the positions of the first groove structure 111 and the second groove structure 112 can be adjusted according to actual needs, so that the solar cell 100 can adapt to the slicing requirements of various cell types such as half-cell, three-cell, or four-cell, improving performance, increasing usage flexibility, and reducing process costs.

[0071] The method for preparing a solar cell according to the embodiments of this application includes steps S10 to S100: Step S10: Provide a substrate 110. The substrate 110 has a first surface 110a and a second surface 110b disposed opposite to each other in the thickness direction. The substrate 110 includes an emitter layer 113 and a body layer 114 in the direction from the first surface 110a to the second surface 110b.

[0072] In some implementations, step S10 specifically includes steps S11 to S12: Step S11: Provide an initial substrate and perform a texturing process on the initial substrate to form a pyramidal textured surface. In some examples, the resistivity of the initial substrate is 0.5 Ω·cm to 20 Ω·cm, and the thickness of the initial substrate is 100 μm to 150 μm.

[0073] As an example, the initial substrate is a single-crystal silicon wafer with a first doping type. For example, the first doping type can be N-type.

[0074] As an example, the pyramid textured surface has a size of 0.5μm to 3μm.

[0075] In one embodiment, in step S11, a chemical solution is used to perform a texturing treatment on the initial substrate. The texturing treatment temperature is 50°C to 80°C, and the reaction time is 200s to 800s. As an example, the chemical solution includes alkaline solutions such as KOH or NaOH.

[0076] Step S12 involves doping a portion of the initial substrate to obtain substrate 110. The doped initial substrate, located on the front side, serves as the emitter layer 113 of substrate 110, while the undoped initial substrate serves as the body layer 114 of substrate 110. Substrate 110 has a first surface 110a and a second surface 110b disposed opposite each other in the thickness direction. Substrate 110 includes the emitter layer 113 and the body layer 114 along the direction from the first surface 110a to the second surface 110b.

[0077] As an example, the initial substrate is an N-type single-crystal silicon wafer. Step S12 specifically includes: performing boron doping treatment on the initial substrate to form a boron-doped layer and a borosilicate glass layer covering the boron-doped layer on the front side of the initial substrate, thereby obtaining substrate 110. The boron-doped layer on the front side of the initial substrate serves as the emitter layer 113 of substrate 110, the undoped initial substrate serves as the body layer 114 of substrate 110, the surface of the boron-doped layer (emitter layer 113) on the front side of the initial substrate away from the body layer 114 is the first surface 110a of substrate 110, and the borosilicate glass layer serves as a mask layer (covering the first surface 110a of substrate 110).

[0078] As an example, the boron doping treatment includes: introducing a boron source at a temperature of 700°C to 900°C, and then stopping the introduction of the boron source; followed by annealing oxidation treatment by introducing oxygen at a temperature of 800°C to 1100°C for a duration of 1000s to 9000s and an oxygen flow rate of 100sccm to 20000sccm; and / or introducing water vapor for a duration of 1000s to 4000s and an oxygen flow rate of 100sccm to 1100sccm.

[0079] In some examples, the thickness of the borosilicate glass layer is 50 nm to 200 nm.

[0080] It is understandable that during texturing and boron doping processes, unintended products such as textured surfaces, boron-doped layers, and borosilicate glass layers may form on the back side of the initial substrate. These unintended products will be removed in subsequent steps.

[0081] Step S20: Remove the emitter layer 113 and part of the body layer 114 of the preset area of ​​the substrate 110 to form the first groove structure 111.

[0082] As one implementation method, a laser can be used to directly remove the borosilicate glass layer, the emitter layer 113, and part of the body layer 114 covering the front preset area of ​​the substrate 110, to form the first groove structure 111.

[0083] As another implementation, a laser can be used to first remove the borosilicate glass layer covering the front preset area of ​​the substrate 110 and the emitter layer 113 of at least a portion of the thickness of the preset area of ​​the substrate 110, and then an alkaline solution can be used to completely remove the emitter layer 113 and the body layer 114 of a portion of the thickness of the preset area to form the first groove structure 111.

[0084] In step S30, the borosilicate glass layer on the back side and the side side of the substrate 110 is removed, and the boron doped layer and textured surface on the back side and the side side of the substrate 110 are removed so that the back side of the substrate 110 forms a polished surface, which serves as the second surface 110b of the substrate 110.

[0085] As an example, removing the borosilicate glass layer on the back side and the side side of the substrate 110 includes: removing the borosilicate glass layer on the back side and the side side of the silicon wafer substrate 110 in a chain wet process, using a chemical solution containing HF, at a temperature of 20°C to 40°C, for a duration of 30s to 180s.

[0086] As an example, removing the boron-doped layer and textured surface from the back and sides of the substrate 110 includes polishing the back and sides of the substrate 110 using an alkaline solution containing KOH or NaOH, at a polishing temperature of 60°C to 90°C, for a duration of 200s to 800s.

[0087] In step S40, a tunneling oxide layer 140 and an intrinsic polysilicon layer covering the tunneling oxide layer 140 are formed on the second surface 110b of the substrate 110. It is understood that during this process, a wrap-around plating (unintended product) may also form on the front surface of the substrate 110.

[0088] As an example, the thickness of the tunneling oxide layer 140 is 1 nm to 2 nm, and the thickness of the intrinsic polysilicon layer is 50 nm to 200 nm. In some examples, the tunneling oxide layer 140 is formed by thermal oxidation at a processing temperature of 550°C to 650°C for 10 min to 30 min. In some examples, the intrinsic polysilicon layer is formed by low-pressure chemical vapor deposition (LPCVD) at a processing temperature of 550°C to 650°C for 10 min to 50 min.

[0089] In step S50, phosphorus diffusion doping and high-temperature crystallization are performed to transform the intrinsic polycrystalline silicon layer into a phosphorus-doped polycrystalline silicon layer 150, and a phosphorus-silicon glass layer is formed on the surface of the phosphorus-doped polycrystalline silicon layer 150. It is understood that during this process, the polycrystalline silicon layer coated around the front side of the substrate 110 will also undergo the aforementioned changes.

[0090] In some examples, the phosphorus-doped polycrystalline silicon layer 150 has a doping concentration of 1-4e20cm. -3 The thickness ranges from 30nm to 180nm, and the thickness of the phosphosilicate glass layer ranges from 20nm to 50nm.

[0091] Step S60: Remove the phosphosilicate glass layer from the front and sides of the substrate 110. As an example, the chemical solution used contains HF, the temperature is 20°C to 40°C, and the time is 30s to 180s.

[0092] Step S70: Remove the polysilicon layer and the remaining phosphosilicate glass layer on the front side of the substrate 110, exposing the boron-doped layer on the front side of the substrate 110, i.e., exposing the first surface 110a of the substrate 110. As an example, when removing the polysilicon layer on the front side of the substrate 110, the chemical solution used contains an alkaline solution such as KOH or NaOH, the temperature is 60°C to 80°C, and the time is 200s to 600s.

[0093] In step S80, a passivation layer 120, a first antireflection layer 130, and a second antireflection layer 160 are formed covering the first surface 110a and the surface of the first groove structure 111, respectively. For example, the passivation layer 120 is an aluminum oxide layer, and the first antireflection layer 130 and the second antireflection layer 160 are silicon nitride layers.

[0094] In step S90, the first electrode 170 and the second electrode 180 are formed.

[0095] Step S100: Remove part of the thickness of the body layer 114 to form the second groove structure 112.

[0096] As an example, in the preparation Figure 2 and Figure 6 In the fabrication of the solar cell 100 shown, step S100 specifically includes: using a laser to remove the first antireflection layer 130, the passivation layer 120, and a portion of the body layer 114 from the target area of ​​the first bottom surface 1111 of the first groove structure 111, forming the second groove structure 112. During the fabrication... Figure 10 and Figure 14When the solar cell 100 shown is used, step S100 specifically includes: using a laser to remove the second antireflection layer 160, the phosphorus-doped polycrystalline silicon layer 150, the tunneling oxide layer 140 and the bulk layer 114 of a certain thickness in the target area to form a second groove structure 112.

[0097] The sliced ​​cell 200 provided in this application embodiment is obtained by cutting the solar cell 100 provided in any of the above embodiments, or by cutting the solar cell 100 prepared by the method of preparing the solar cell provided in any of the above embodiments.

[0098] In this embodiment, the substrate 110 is provided with a first groove structure 111 and a second groove structure 112. The first groove structure 111 penetrates the emitter layer 113 and extends to the body layer 114. The surfaces of the first groove structure 111 (first bottom surface 1111 and first side surface 1112) are completely covered by a passivation layer 120, thereby achieving no emitter polarization and effective surface passivation in this region. Furthermore, the inclined first side surface 1112, compared to a vertical first side surface, reduces local stress concentration, enhances the mechanical stability of the first groove structure 111, and prevents cracks from forming during subsequent slab or component packaging. By reducing the risk of cracking and protecting the structural integrity, the inclined first side surface 1112 helps maintain the continuity of the carrier transport channel, thereby improving conversion efficiency. The second groove structure 112 is aligned with the bottom projection of the first groove structure 111 in the thickness direction. During cell slicing, slicing can be performed along the path guided by the first groove structure 111 and the second groove structure 112. This not only provides clear stress extension guidance for slicing, making slicing faster and more accurate, but also minimizes damage to the passivation layer 120 and avoids direct damage to the emitter layer 113 during slicing. Furthermore, the sides of the sliced ​​cells 200 still have the passivation layer 120 protecting the emitter layer 113, thereby improving the fill factor (FF) and conversion efficiency of the cells. In addition, the positions of the first groove structure 111 and the second groove structure 112 can be adjusted according to actual needs, so that the solar cell 100 can adapt to the slicing requirements of various cell types such as half-cell, three-cell, or four-cell, improving performance, increasing usage flexibility, and reducing process costs.

[0099] As one implementation, the front and back partial structures near the cut edge of the sliced ​​battery 200 are respectively as follows: Figure 3 and Figure 5 As shown, the sliced ​​battery 200 is composed of Figure 2 and Figure 4 The solar cell 100 shown is obtained by cutting; or, the front and back partial structures near the cut edge of the sliced ​​cell 200 are respectively as shown in the figure. Figure 9 and Figure 11As shown, the sliced ​​battery 200 is composed of Figure 8 and Figure 10 The solar cell 100 shown is obtained by cutting it into pieces. As an example, in the fabrication... Figure 3 and Figure 5 The sliced ​​battery shown Figure 9 and Figure 11 When the sliced ​​cell is formed, after the second groove structure 112 is formed, mechanical stress (e.g., bending, rolling, or stretching) can be applied to cause the solar cell 100 to break along a predetermined path, thereby forming the sliced ​​cell 200. In some preferred examples, the predetermined path can be a first virtual straight line 300 or approximately a first virtual straight line 300.

[0100] As one implementation, the local structure near the cut edge of the sliced ​​battery 200 is as follows: Figure 7 As shown, the sliced ​​battery 200 is composed of Figure 6 The solar cell 100 shown is obtained by cutting; or, the local structure near the cut edge of the sliced ​​cell 200 is as follows: Figure 13 and Figure 15 As shown, the sliced ​​battery 200 is composed of Figure 12 and Figure 14 The solar cell 100 shown is obtained by cutting it into pieces. As an example, in the fabrication... Figure 7 The sliced ​​battery shown Figure 13 and Figure 15 When slicing the battery as shown, after forming the second groove structure 112, the second groove structure 112 is used as the crack initiation source. A thermal cracking laser is used to scan along the first virtual straight line 300 and then cooled to cause the solar cell 100 to generate thermally induced cracks that extend along the path defined by the first virtual straight line 300, thereby achieving slicing to form the sliced ​​battery 200.

[0101] It should be noted that sliced ​​cells can also be obtained by cutting solar cells in other ways, which can be set according to the actual situation, and will not be elaborated here.

[0102] The tandem solar cell provided in this application includes a top cell, an intermediate connecting layer, and a bottom cell, which are stacked together. The top cell is a perovskite solar cell, a cadmium telluride solar cell, a copper indium gallium selenide solar cell, or a gallium arsenide solar cell. The bottom cell is a solar cell 100 provided in any of the above embodiments, a solar cell 100 prepared by the preparation method of a solar cell provided in any of the above embodiments, or a sliced ​​cell 200 provided in any of the above embodiments.

[0103] In this embodiment, the substrate 110 is provided with a first groove structure 111 and a second groove structure 112. The first groove structure 111 penetrates the emitter layer 113 and extends to the body layer 114. The surfaces of the first groove structure 111 (first bottom surface 1111 and first side surface 1112) are completely covered by a passivation layer 120, thereby achieving no emitter polarization and effective surface passivation in this region. Furthermore, the inclined first side surface 1112, compared to a vertical first side surface, reduces local stress concentration, enhances the mechanical stability of the first groove structure 111, and prevents cracks from forming during subsequent slab or component packaging. By reducing the risk of cracking and protecting the structural integrity, the inclined first side surface 1112 helps maintain the continuity of the carrier transport channel, thereby improving conversion efficiency. The second groove structure 112 is aligned with the bottom projection of the first groove structure 111 in the thickness direction. During cell slicing, slicing can be performed along the path guided by the first groove structure 111 and the second groove structure 112. This not only provides clear stress extension guidance for slicing, making slicing faster and more accurate, but also minimizes damage to the passivation layer 120 and avoids direct damage to the emitter layer 113 during slicing. Furthermore, the sides of the sliced ​​cells 200 still have the passivation layer 120 protecting the emitter layer 113, thereby improving the fill factor (FF) and conversion efficiency of the cells. In addition, the positions of the first groove structure 111 and the second groove structure 112 can be adjusted according to actual needs, so that the solar cell 100 can adapt to the slicing requirements of various cell types such as half-cell, three-cell, or four-cell, improving performance, increasing usage flexibility, and reducing process costs.

[0104] The photovoltaic modules provided in this application include the solar cell 100 provided in any of the above embodiments, or the solar cell 100 prepared by the method of preparing the solar cell provided in any of the above embodiments, or the sliced ​​cell 200 provided in any of the above embodiments, or the stacked cell provided in any of the above embodiments.

[0105] In this embodiment, the substrate 110 is provided with a first groove structure 111 and a second groove structure 112. The first groove structure 111 penetrates the emitter layer 113 and extends to the body layer 114. The surfaces of the first groove structure 111 (first bottom surface 1111 and first side surface 1112) are completely covered by a passivation layer 120, thereby achieving no emitter polarization and effective surface passivation in this region. Furthermore, the inclined first side surface 1112, compared to a vertical first side surface, reduces local stress concentration, enhances the mechanical stability of the first groove structure 111, and prevents cracks from forming during subsequent slab or component packaging. By reducing the risk of cracking and protecting the structural integrity, the inclined first side surface 1112 helps maintain the continuity of the carrier transport channel, thereby improving conversion efficiency. The second groove structure 112 is aligned with the bottom projection of the first groove structure 111 in the thickness direction. During cell slicing, slicing can be performed along the path guided by the first groove structure 111 and the second groove structure 112. This not only provides clear stress extension guidance for slicing, making slicing faster and more accurate, but also minimizes damage to the passivation layer 120 and avoids direct damage to the emitter layer 113 during slicing. Furthermore, the sides of the sliced ​​cells 200 still have the passivation layer 120 protecting the emitter layer 113, thereby improving the fill factor (FF) and conversion efficiency of the cells. In addition, the positions of the first groove structure 111 and the second groove structure 112 can be adjusted according to actual needs, so that the solar cell 100 can adapt to the slicing requirements of various cell types such as half-cell, three-cell, or four-cell, improving performance, increasing usage flexibility, and reducing process costs.

[0106] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] The above embodiments merely illustrate preferred implementations of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims.

Claims

1. A solar cell, characterized by, include: A substrate having a first surface and a second surface disposed opposite each other in the thickness direction, the substrate including an emitter layer and a body layer along the direction from the first surface to the second surface; A first groove structure is disposed on a first surface of the substrate. The first groove structure penetrates the emitter layer along the thickness direction and extends to the body layer. The first groove structure includes a first bottom surface that is recessed inward relative to the first surface and a first side surface that extends obliquely from the first surface and is connected to the first bottom surface. A passivation layer covers the first surface, the first bottom surface, and the first side surface; and A second groove structure is provided on the first or second surface of the substrate, and the projection of the second groove structure in the thickness direction is located within the projection of the first bottom surface in the thickness direction.

2. The solar cell of claim 1, wherein, The first groove structure penetrates the substrate along a first direction, which is perpendicular to the thickness direction.

3. The solar cell of claim 1, wherein, The depth of the first groove structure is 1 μm to 10 μm; and / or, The width of the first groove structure is 200 μm to 1000 μm; and / or, The slope of the first groove structure is 40° to 80°.

4. The solar cell as described in claim 1, characterized in that, The second groove structure penetrates the substrate along a first direction, which is perpendicular to the thickness direction.

5. The solar cell as described in claim 1, characterized in that, The first groove structure and the second groove structure are arranged in a one-to-one correspondence, and the second groove structure is arranged at one end of the substrate in the first direction; or, one first groove structure and two second groove structures are arranged in a corresponding manner, one second groove structure is arranged at one end of the substrate in the first direction, and the other second groove structure is arranged at the other end of the substrate in the first direction; Wherein, the first direction is perpendicular to the thickness direction.

6. The solar cell as described in claim 5, characterized in that, The length of the second groove structure in the first direction is 1mm to 2mm.

7. The solar cell according to claim 1, characterized in that, The depth of the first groove structure is greater than the depth of the second groove structure; and / or, the width of the first groove structure is greater than the width of the second groove structure.

8. The solar cell as claimed in claim 1, characterized in that, The projection of the first groove structure in the thickness direction is symmetrical about a first virtual straight line, and the projection of the second groove structure in the thickness direction is symmetrical about a first virtual straight line, wherein the first virtual straight line is perpendicular to the thickness direction.

9. The solar cell according to claim 1, characterized in that, The depth of the second groove structure is 1 μm to 2 μm; and / or, The width of the second groove structure is 50 μm to 150 μm; and / or, The slope of the second groove structure is 80° to 90°.

10. The solar cell according to claim 1, characterized in that, The second groove structure includes a second bottom surface recessed into the body layer relative to the first bottom surface, and a second side surface connecting the second bottom surface and the passivation layer on the side away from the substrate.

11. The solar cell according to claim 1, characterized in that, The second groove structure includes a second bottom surface recessed into the body layer relative to the second surface and a second side surface connecting the second bottom surface and the second surface.

12. A method for preparing a solar cell, used to prepare the solar cell according to any one of claims 1 to 11, characterized in that, include: A substrate is provided, the substrate having a first surface and a second surface disposed opposite to each other in the thickness direction, the substrate including an emitter layer and a body layer along the direction from the first surface to the second surface; The emitter layer and part of the body layer in the predetermined region of the substrate are removed to form a first groove structure; A passivation layer is formed covering the first surface and the surface of the first groove structure; A portion of the thickness of the body layer is removed to form a second groove structure.

13. A sliced ​​battery, characterized in that, It is obtained by cutting a solar cell according to any one of claims 1 to 11; or by cutting a solar cell prepared by the method of preparing a solar cell according to claim 12.

14. A stacked battery, characterized in that, include: Top cell, which can be a perovskite cell, cadmium telluride solar cell, copper indium gallium selenide solar cell, or gallium arsenide solar cell; Intermediate connection layer; and The base cell is a solar cell according to any one of claims 1-11, or a solar cell prepared by the method of preparing a solar cell according to claim 12, or a sliced ​​cell according to claim 13; The top battery, the intermediate connecting layer, and the bottom battery are stacked and connected.

15. A photovoltaic module, characterized in that, This includes the solar cell according to any one of claims 1-11, or the solar cell prepared by the method of preparing the solar cell according to claim 12, or the sliced ​​cell according to claim 13, or the stacked cell according to claim 14.

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