A back contact cell and photovoltaic module

Abstract

The application discloses a back contact cell and a photovoltaic module, and relates to the technical field of photovoltaics, which aims to reduce the hot spot risk of the back contact cell and improve the burnout resistance. The back contact cell comprises a semiconductor substrate, a first doped semiconductor layer, a second doped semiconductor layer, a first current collecting electrode and a second current collecting electrode. There is an isolation region between the main body region of the first doped semiconductor layer and the main body region of the second doped semiconductor layer, and the partial region of the first doped semiconductor layer and the partial region of the second doped semiconductor layer are connected to form an abutting region. In the first surface of the semiconductor substrate, the region below the abutting region is a first region. At least one strip-shaped recess and / or strip-shaped protrusion is arranged in the first surface of the semiconductor substrate. The strip-shaped recess and / or strip-shaped protrusion extend across from one side to the other side of the two sides of the at least one first region distributed in the width direction.

Description

[0001] This application claims priority to Chinese Patent Application No. 202511384007.2, filed on September 25, 2025, entitled "A Back Contact Battery and Photovoltaic Module", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of photovoltaic technology, and more particularly to a back contact battery and a photovoltaic module. Background Technology

[0003] Back-contact solar cells are solar cells with no electrodes on the light-facing side, and both the positive and negative electrodes are located on the back-facing side of the cell. This reduces the shading of the cells by the electrodes, increases the short-circuit current, and improves the energy conversion efficiency of the cells.

[0004] During actual use, back-contact solar cells may be obstructed by bird droppings, leaves, dust, or other debris. This obstruction can cause the cells to overheat and generate hot spots. If the temperature of these hot spots exceeds a certain threshold, it can lead to problems such as photovoltaic module delamination, backsheet burning, and glass shattering, ultimately rendering the entire cell unusable. In severe cases, it can even pose a fire risk. Summary of the Invention

[0005] The purpose of this application is to provide a back-contact battery and a photovoltaic module to reduce the risk of hot spots in the back-contact battery and improve its resistance to burn-out.

[0006] To achieve the above objectives, in a first aspect, this application provides a back-contact battery, comprising: a semiconductor substrate, a first doped semiconductor layer, a second doped semiconductor layer, a first current collector electrode, and a second current collector electrode. The second doped semiconductor layer and the first doped semiconductor layer have opposite conductivity types. The semiconductor substrate includes a first surface and a second surface facing each other. The first doped semiconductor layer and the second doped semiconductor layer are disposed on the first surface, and an isolation region is formed between the main regions of the first doped semiconductor layer and the main regions of the second doped semiconductor layer. A portion of the first doped semiconductor layer and a portion of the second doped semiconductor layer are connected to form a docking region. The first current collector electrode is disposed on the side of the first doped semiconductor layer facing away from the semiconductor substrate; the second current collector electrode is disposed on the side of the second doped semiconductor layer facing away from the semiconductor substrate, and at least one of the first current collector electrode and the second current collector electrode is spaced apart from the docking region. In the first surface of the semiconductor substrate, the region located below the docking region is a first region. At least one strip-shaped recess and / or strip-shaped protrusion is provided in the first surface of the semiconductor substrate. The strip-shaped recess and / or strip-shaped protrusion extends from one side of at least one of the two sides of the first region, which are distributed opposite each other in the width direction, to the other side.

[0007] A first doped semiconductor layer and a second doped semiconductor layer with opposite conductivity types are disposed on a first surface of a semiconductor substrate. Furthermore, a portion of the first doped semiconductor layer and a portion of the second doped semiconductor layer are connected to form a docking region. Within at least a portion of this docking region, the first doped semiconductor layer and the second doped semiconductor layer can form a built-in diode structure with a low reverse breakdown voltage. When the back contact battery is blocked, leakage current flows through at least a localized area of ​​the docking region and is discharged through the main body regions of the first doped semiconductor layer and the second doped semiconductor layer adjacent to the docking region. When at least one strip-shaped recess and / or strip-shaped protrusion is provided within the first surface of the semiconductor substrate, and the strip-shaped recess and / or strip-shaped protrusion extends from one side of at least one first region located below the docking region along its width direction to the other side, on the one hand, the surface of the first region of the semiconductor substrate has an uneven undulating morphology, which can increase the specific surface area of ​​the first region; correspondingly, the first doped semiconductor layer and the second doped semiconductor layer constituting the docking region and formed on the first region by a deposition process also have a large coverage area, which is beneficial for increasing the interfacial area between the first doped semiconductor layer and the second doped semiconductor layer in the docking region. The increased leakage contact area helps to increase the leakage current, reduce the risk of hot spots on the back contact battery, and improve the back contact battery's resistance to burnout. On the other hand, the strip-shaped recess and / or strip-shaped protrusion span at least one first region along the width direction of the first region. Correspondingly, the first doped semiconductor layer and the second doped semiconductor layer located on the strip-shaped recess and / or strip-shaped protrusion also extend along the width direction of the first region. This part of the first doped semiconductor layer and this part of the second doped semiconductor layer form a strip-shaped fast carrier channel, which facilitates leakage current transmission, further reduces the risk of hot spots on the back contact battery, and further improves the back contact battery's resistance to burnout.

[0008] As one possible implementation, along the thickness direction of the semiconductor substrate, the thickness L1 of the portion of the first doped semiconductor layer and / or the second doped semiconductor layer located on the side of the strip-shaped recess and / or the strip-shaped protrusion is greater than the thickness L2 of the rest of the layer. This configuration enhances the conductivity of the portion of the first doped semiconductor layer and / or the second doped semiconductor layer located on the side of the strip-shaped recess and / or the strip-shaped protrusion, reduces the transport resistance of this portion, forms a fast carrier channel, avoids the increase in parasitic absorption caused by overall thickness, and ultimately further reduces the risk of hot spots on the back contact battery.

[0009] As one possible implementation, the ratio of L2 to L1 is greater than or equal to 1.05 and less than 5; and / or, the difference between L2 and L1 is greater than or equal to 25 nm and less than 800 nm. This setting, when the ratio of L2 to L1 is within the above range, prevents L2 from becoming too large and / or L1 from becoming too small. This helps ensure that the portions of the first doped semiconductor layer and / or the second doped semiconductor layer located on the sides of the strip-shaped recesses and / or strip-shaped protrusions have high conductivity, facilitating the formation of fast carrier channels. Furthermore, it avoids the increase in parasitic absorption in the remaining portions of the first doped semiconductor layer and / or the second doped semiconductor layer due to an excessively large L2, thus improving the operating performance of the back contact battery. In addition, it can prevent L2 from being too small and / or L1 from being too large due to the ratio of L2 to L1 being too small. This is beneficial for the remaining parts of the first doped semiconductor layer and / or the second doped semiconductor layer to have a good field passivation effect. It is also beneficial for controlling the thickness of the first doped semiconductor layer and / or the second doped semiconductor layer on the side of the strip-shaped recess and / or the strip-shaped protrusion within an appropriate range, preventing excessive leakage current, and enabling the back contact battery to have a high conversion efficiency in the forward voltage region.

[0010] As one possible implementation, at least one strip-shaped recess and / or strip-shaped protrusion includes multiple substructures. At least a portion of the regions of at least two adjacent substructures are merged. This arrangement facilitates the embedding of smaller-sized adjacent edges of two adjacent substructures within larger-sized portions, forming a better connection. This results in each portion of the strip-shaped recess and / or strip-shaped protrusion having a larger width along its extension direction, increasing the proportion of the strip-shaped recess and / or strip-shaped protrusion in the first region. This increases the specific surface area of ​​the first region, thereby increasing the leakage contact area between the first and second doped semiconductor layers in the mating region and reducing the risk of hot spots on the back contact battery.

[0011] As one possible implementation, at least one strip-shaped recess and / or strip-shaped protrusion includes multiple substructures. In the same strip-shaped recess, the distance between the bottoms of two adjacent substructures along the thickness direction of the semiconductor substrate is less than 2 μm, or in the same strip-shaped protrusion, the distance between the tops of two adjacent substructures along the thickness direction of the semiconductor substrate is less than 2 μm.

[0012] When the distance between the bottoms of two adjacent substructures along the thickness direction of the semiconductor substrate in the same strip-shaped recess is less than 2 μm, the undulation of the bottoms of different substructures along the thickness direction of the semiconductor substrate is smaller. This is beneficial for improving the coverage of the first doped semiconductor layer and / or the second doped semiconductor layer in the strip-shaped recess, improving the formation quality of the first doped semiconductor layer and / or the second doped semiconductor layer in the strip-shaped recess, and improving the yield of the back contact battery. The application principle of the beneficial effect of the distance between the tops of two adjacent substructures along the thickness direction of the semiconductor substrate being less than 2 μm in the same strip-shaped protrusion can be referred to the previous text, and will not be repeated here.

[0013] As one possible implementation, the width of at least one strip-shaped recess and / or strip-shaped protrusion is greater than or equal to 200 nm and less than or equal to 80 μm. This configuration prevents the difficulty of depositing the first and / or second doped semiconductor layers within the strip-shaped recess and / or protrusion due to excessively small widths, ensuring good deposition quality and high coverage of the first and / or second doped semiconductor layers within the strip-shaped recess and / or protrusion. This facilitates a larger leakage contact area between the first and second doped semiconductor layers in the docking region, reducing the risk of hot spots. Furthermore, it prevents the docking region from becoming excessively large due to excessively large widths of the strip-shaped recess and / or protrusion, helping to control the leakage current within an appropriate range and ensuring high conversion efficiency of the back contact battery in the forward voltage region.

[0014] As one possible implementation, the depth of at least one strip-shaped recess is greater than or equal to 50 nm and less than or equal to 30 μm; and / or the height of at least one strip-shaped protrusion is greater than or equal to 50 nm and less than or equal to 30 μm.

[0015] At least one strip-shaped recess has a recess depth within the aforementioned range. This prevents the increase in the thickness of the first and second doped semiconductor layers on the side of the strip-shaped recess from being too small, and also prevents a small increase in the area of ​​the side of the first and second doped semiconductor layers corresponding to the strip-shaped recess. This is beneficial for increasing the conductivity of the portion of the first and second doped semiconductor layers on the side of the strip-shaped recess, as well as their leakage contact area, thereby reducing the risk of hot spots on the back contact battery. The application principle of the beneficial effect of at least one strip-shaped protrusion having a protrusion height greater than or equal to 50 nm and less than or equal to 30 μm can be referred to the application principle of the beneficial effect of at least one strip-shaped recess having a recess depth greater than or equal to 50 nm and less than or equal to 30 μm described above, and will not be repeated here.

[0016] As one possible implementation, the number of strip-shaped recesses and / or strip-shaped protrusions on the surface of at least one first region is less than or equal to 10. This configuration prevents excessive leakage current caused by an excessive number of strip-shaped recesses and / or strip-shaped protrusions in a single first region, ensuring high conversion efficiency of the back contact battery; at the same time, it prevents the surface of the first region from being too rough, improving the film quality and passivation effect of the first doped semiconductor layer and the second doped semiconductor layer formed on the first region.

[0017] As one possible implementation, when the first surface comprises multiple first regions, the first region having strip-shaped recesses and / or strip-shaped protrusions accounts for more than or equal to 10% and less than or equal to 100% of all the first regions. The beneficial effect in this case can be understood by referring to the beneficial effect described above when the number of strip-shaped recesses and / or strip-shaped protrusions on the surface of at least one first region is less than or equal to 10. Furthermore, it can prevent the leakage contact area of ​​the first and second doped semiconductor layers in the mating region from increasing too little due to the small number of first regions having strip-shaped recesses and / or strip-shaped protrusions, thus reducing the risk of hot spots on the back contact battery.

[0018] As one possible implementation, the substructure is a tower-based structure. Compared to a textured structure, the top or bottom surface of the tower-based structure is relatively flat, which helps to improve the formation quality of the first and / or second doped semiconductor layers formed on the strip-shaped recesses and / or strip-shaped protrusions, and thus improves the conversion efficiency of the back contact cell.

[0019] As one possible implementation, in the first surface of the semiconductor substrate, the region corresponding to the main region of the first doped semiconductor layer is defined as the second region, and the region corresponding to the main region of the second doped semiconductor layer is defined as the third region. At least one strip-shaped recess and / or strip-shaped protrusion located in at least one first region further extends into at least a portion of the surface of the second region and / or the third region adjacent to the first region.

[0020] As mentioned above, when the back contact battery is blocked, the leakage current needs to pass through the docking region and be discharged through the main body regions of the first and second doped semiconductor layers adjacent to the docking region. In the first surface, when at least a portion of the surface of the second region located below the main body region of the first doped semiconductor layer and / or the third region located below the main body region of the second doped semiconductor layer is provided with strip-shaped recesses and / or strip-shaped protrusions extending from the first region, the coverage area of ​​the main body regions of the first and / or the main body regions of the second doped semiconductor layers near the docking region on the first surface can be increased. Secondly, when the portions of the first doped semiconductor layer and / or the second doped semiconductor layer located on the sides of the strip-shaped recesses and / or strip-shaped protrusions have a greater thickness, at least one strip-shaped recess and / or strip-shaped protrusion located in at least one first region also extends into at least a portion of the surface of the second region and / or the third region adjacent to the first region. This further enhances the conductivity between the main region of the first doped semiconductor layer and / or the main region of the second doped semiconductor layer and the docking region, forming a strip-shaped fast channel for charge carriers, which facilitates leakage current transmission, further reduces the risk of hot spots in the back contact battery, and further improves the burn-out resistance of the back contact battery.

[0021] As one possible implementation, along the thickness direction of the semiconductor substrate, the surface of one of the second and third regions has a height difference from the surface of the first region. This arrangement, with the height difference between the strip-shaped recesses and / or protrusions located in different regions, extends the length of the strip-shaped recesses and / or protrusions, which helps to disperse leakage current.

[0022] As one possible implementation, at least one strip-shaped recess and / or strip-shaped protrusion located in the first region is collinear with the corresponding strip-shaped recess and / or strip-shaped protrusion in the second and / or third regions adjacent to the first region.

[0023] When the portions of the first and / or second doped semiconductor layers located on the sides of the strip-shaped recesses and / or protrusions have a greater thickness, these portions exhibit higher conductivity, and the corresponding leakage current preferentially propagates within these portions. Therefore, by aligning at least one strip-shaped recess and / or protrusion located in the first region, and corresponding strip-shaped recesses and / or protrusions in the adjacent second and / or third regions, the portions of the first and second doped semiconductor layers with lower propagation losses along the leakage current propagation path can be connected in series through these collinear strip-shaped recesses and / or protrusions. This facilitates leakage current passage, shortens the leakage current propagation path, and reduces the risk of hot spots on the back contact battery.

[0024] As one possible implementation, along the width direction of the first region, at least one pair of opposing first regions are provided on both sides of at least one second region or third region, and the strip-shaped recesses and / or strip-shaped protrusions located in the opposing first regions extend and intersect in a direction of mutual approach. With this arrangement, the two opposing docking regions can be connected in series through the main region of the first doped semiconductor layer or the main region of the second doped semiconductor layer located above the extending strip-shaped recesses and / or strip-shaped protrusions. This not only increases the leakage current, but also allows the leakage current at both docking regions to be discharged through the main region of the first doped semiconductor layer or the main region of the second doped semiconductor layer located above the strip-shaped recesses and / or strip-shaped protrusions, thus shortening the leakage current transmission path, reducing leakage current transmission loss, and reducing the risk of hot spots on the back contact battery.

[0025] As one possible implementation, at least one strip-shaped recess and / or strip-shaped protrusion extends from the first region to the orthographic projection region of the first collector electrode in the second region; and / or, at least one strip-shaped recess and / or strip-shaped protrusion extends from the first region to the orthographic projection region of the second collector electrode in the third region.

[0026] Taking at least one strip-shaped recess and / or strip-shaped protrusion extending from the first region to the orthogonal projection area of ​​the first collector electrode in the second region as an example: In this case, the first doped semiconductor layer above the strip-shaped recess and / or strip-shaped protrusion extending from the first region to the orthogonal projection area of ​​the first collector electrode in the second region has a large coverage area on the strip-shaped recess and / or strip-shaped protrusion. When the first doped semiconductor layer has a larger thickness on the side of the strip-shaped recess and / or strip-shaped protrusion, it can also enhance the conductivity of the portion of the first doped semiconductor layer located on the leakage current transmission path between the docking region and the first collector electrode, which is beneficial to reduce its own leakage current transmission loss and reduce the risk of hot spots on the back contact battery.

[0027] As one possible implementation, the first surface also includes a trench region located between the second and third regions. The trench region serves to physically insulate a portion of the first doped semiconductor layer and a portion of the second doped semiconductor layer. Specifically, at least one strip-shaped recess and / or strip-shaped protrusion extending from the first region into the second region terminates at the boundary between the second region and the trench region; and / or, at least one strip-shaped recess and / or strip-shaped protrusion extending from the first region into the third region terminates at the boundary between the third region and the trench region. This configuration eliminates the need to provide strip-shaped recesses and / or protrusions within the trench region where leakage current is not transmitted, reducing the processing area required to form the strip-shaped recesses and / or protrusions and improving manufacturing efficiency. In addition, at least one strip-shaped recess and / or strip-shaped protrusion extending from the first region to the second and / or third region stops extending only at the boundary of the trench region, which helps to ensure that the leakage current has low transmission loss at each part of the transmission path between the docking region and the first collector electrode and / or the second collector electrode, thereby reducing the risk of hot spots in the contact battery.

[0028] As one possible implementation, strip-shaped recesses and / or strip-shaped protrusions are provided on the surface of the regions in the second and / or third regions that do not intersect with the extending direction of the adjacent first region. The extending directions of these strip-shaped recesses and / or protrusions on the surface of the regions in the second and / or third regions that do not intersect with the extending direction of the adjacent first region are parallel to the extending directions of the strip-shaped recesses and / or protrusions located in the first region. This configuration helps to enhance the conductivity of the main region of the first doped semiconductor layer and / or the portion of the main region of the second doped semiconductor layer that does not intersect with the extending direction of the adjacent docking region, reducing transmission resistance. It also facilitates current transmission to the docking region along the extending direction of the strip-shaped recesses and / or protrusions, reducing transmission losses and mitigating the risk of hot spots on the back contact battery. Furthermore, it enhances the carrier collection capability of the main region of the first doped semiconductor layer and / or the second doped semiconductor layer, thereby improving the conversion efficiency of the back contact battery in the forward voltage region.

[0029] As one possible implementation, when there is a height difference between the surface of one of the second and third regions and the surface of the first region, and the surface of the other region is at the same height as the surface of the first region, the depth of the strip-shaped recess in at least one of the three regions with a greater height is greater than the depth of the strip-shaped recess in at least one of the three regions with a smaller height, or the height of the strip-shaped protrusion in at least one of the three regions with a greater height is less than the height of the strip-shaped protrusion in at least one of the three regions with a smaller height. This arrangement helps to reduce the height difference between the bottom of the strip-shaped recess in the region with a height difference from the surface of the first region and the bottom of the strip-shaped recess in the surface of the first region; or it helps to reduce the height difference between the top of the strip-shaped protrusion in the region with a height difference from the surface of the first region and the top of the strip-shaped protrusion in the surface of the first region. This reduces the coverage length of the first or second doped semiconductor layer at the boundary between the two regions with a height difference, which helps to shorten the transmission distance of leakage current at the boundary, reduce transmission loss, and reduce the risk of hot spots on the back contact battery.

[0030] As one possible implementation, the width of the strip-shaped recess and / or strip-shaped protrusion located in at least one of the three regions with a smaller height is greater than the width of the strip-shaped recess and / or strip-shaped protrusion located in at least one of the three regions with a larger height. This arrangement facilitates the connection between the strip-shaped recess and / or strip-shaped protrusion located in the three regions with a larger height and the strip-shaped recess and / or strip-shaped protrusion located in the three regions with a smaller height after extending to the region boundary. This facilitates the transmission of leakage current in the docking region above the first region and in the main regions of the first and second doped semiconductor layers located above the second and third regions, which have a surface height difference from the first region, thus reducing transmission losses. Furthermore, the larger width of the strip-shaped recess and / or strip-shaped protrusion located in at least one of the three regions with a smaller height results in a larger specific surface area, allowing the first or second doped semiconductor layer located in the three regions with a smaller height to have a larger leakage current transmission area. The strip-shaped recesses and / or strip-shaped protrusions within the at least one with a larger height have a smaller width, resulting in a smaller specific surface area. This allows the first or second doped semiconductor layer located on the at least one with a smaller height to have a smaller leakage current transmission area. This facilitates the transmission of leakage current between the first and second doped semiconductor layers in the docking region from above the first region with a relatively smaller specific surface area to above the second or third region with a larger specific surface area. The corresponding transmission loss along the leakage current transmission path gradually decreases, achieving relay conduction of leakage current and reducing the risk of hot spots on the back contact battery.

[0031] As one possible implementation, the first and second regions have the same surface height, and along the direction from the second surface to the first surface, the surface height of the third region is less than that of the first region. The width of the strip-shaped recesses and / or strip-shaped protrusions located in the third region is greater than the width of the strip-shaped recesses and / or strip-shaped protrusions located in the first region. A portion of the second doped semiconductor layer also extends from the third region into the trench region and covers a portion of the first doped semiconductor layer. With this configuration, it can be understood that, along the thickness direction away from the semiconductor substrate, the surface undulation of the first doped semiconductor layer near the second region and corresponding to the strip-shaped recess and / or strip-shaped protrusion is greater than the surface undulation of the side away from the second region and corresponding to the strip-shaped recess and / or strip-shaped protrusion. As a result, the surface undulation of the second doped semiconductor layer in the first region corresponding to the strip-shaped recess and / or strip-shaped protrusion is smaller. When the width of the strip-shaped recess and / or strip-shaped protrusion in the third region is larger, the undulation of the second doped semiconductor layer in the third region located at the strip-shaped recess and / or strip-shaped protrusion can be increased. That is, at least the leakage current transmission area of ​​the second doped semiconductor layer in the third region is increased, the transmission resistance is reduced, which is conducive to the relay conduction of leakage current and reduces the risk of hot spots on the back contact battery.

[0032] As one possible implementation, multiple first current collector electrodes and multiple second current collector electrodes extend along a first direction and are alternately distributed along a second direction. The first and second directions are perpendicular. The angle between the extending direction of at least one strip-shaped recess and / or strip-shaped protrusion and the second direction is less than 20°. This arrangement, with a smaller angle between the extending direction of at least one strip-shaped recess and / or strip-shaped protrusion and the alternating distribution direction of the first and second current collector electrodes, helps to shorten the transmission path of leakage current between the first and second current collector electrodes, reducing transmission losses and the risk of hot spots on the back contact battery.

[0033] As one possible implementation, at least one first region has at least two strip-shaped recesses and / or strip-shaped protrusions on its surface. Specifically, within the same first region, the angle between the extending direction of one strip-shaped recess or protrusion and the extending direction of another adjacent strip-shaped recess or protrusion is less than or equal to 20°; and / or, strip-shaped recesses and protrusions are simultaneously provided within the same first region, and the strip-shaped recesses and protrusions are alternately distributed along the length of the first region.

[0034] When the angle between the extending direction of one strip-shaped recess or strip-shaped protrusion and the extending direction of another adjacent strip-shaped recess or strip-shaped protrusion within the same first region surface is less than or equal to 20°, the angle between different strip-shaped recesses and / or strip-shaped protrusions is small, and the leakage current flows through the portion of the docking region located above different strip-shaped recesses and / or strip-shaped protrusions with approximately the same path length, which helps to reduce transmission loss and reduce the risk of hot spots on the back contact battery.

[0035] In addition, when strip-shaped recesses and strip-shaped protrusions are simultaneously provided on the surface of the same first region, and the strip-shaped recesses and strip-shaped protrusions are alternately distributed along the length of the first region, there is a large height difference in the area between the strip-shaped recesses and strip-shaped protrusions. This is beneficial to increase the specific surface area of ​​the first region at this location, thereby increasing the leakage contact area of ​​the first doped semiconductor layer and the second doped semiconductor layer in the docking region. This is beneficial to increase the leakage current and reduce the risk of hot spots on the back contact battery.

[0036] As one possible implementation, the length of at least one docking region is greater than or equal to 20 μm and less than or equal to 1000 μm. This setting can prevent the docking region from forming on the first surface of the semiconductor substrate due to its excessively small length. The alignment accuracy between the docking region and the strip-shaped recesses and / or strip-shaped protrusions provided on the first surface of the semiconductor substrate is required to be high, thereby reducing the risk of hot spots on the back contact battery and simplifying the manufacturing process.

[0037] As one possible implementation, the width of at least one isolation region is greater than or equal to 20 μm and less than or equal to 1000 μm. This setting prevents excessively large carrier recombination rates due to an excessively small isolation region width, ensuring high conversion efficiency of the back-contact battery in the forward voltage region. Furthermore, it prevents low carrier collection efficiency in the isolation region due to an excessively large isolation region width. Secondly, in some cases, the width of the isolation region affects the width of the docking region. Therefore, when the width of the isolation region is within the aforementioned range, it also prevents an excessively large isolation region from resulting in a large docking region width, which is beneficial for controlling the leakage contact area between the first and second doped semiconductor layers within the docking region and thus controlling the leakage current.

[0038] As one possible implementation, the length of at least one mating area is greater than the distance between two adjacent strip-shaped recesses and / or strip-shaped protrusions. This arrangement helps ensure that the mating area can be positioned above at least one strip-shaped recess or strip-shaped protrusion, reducing the risk of hot spots on the back contact battery.

[0039] Secondly, this application provides a photovoltaic module including a cell string and an encapsulation layer. The cell string is formed by connecting multiple back-contact cells as provided in the first aspect and its various implementations. The encapsulation layer covers the surface of the cell string.

[0040] The beneficial effects of the second aspect and its various implementations in this application can be found in the analysis of the beneficial effects of the first aspect and its various implementations, and will not be repeated here. Attached Figure Description

[0041] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A longitudinal sectional view of the back contact battery provided in the embodiments of this application. Figure 1 ; Figure 2 A schematic diagram showing the distribution of the first doped semiconductor layer and the second doped semiconductor layer on the first surface of the back contact battery provided in this application embodiment. Figure 1 ; Figure 3 A schematic diagram showing the distribution of the first doped semiconductor layer and the second doped semiconductor layer on the first surface of the back contact battery provided in this application embodiment. Figure 2 ; Figure 4 A schematic diagram showing the distribution of the first doped semiconductor layer and the second doped semiconductor layer on the first surface of the back contact battery provided in this application embodiment. Figure 3 ; Figure 5 A longitudinal sectional view of the back contact battery provided in the embodiments of this application. Figure 2 ; Figure 6 A schematic diagram showing the distribution of the first doped semiconductor layer and the second doped semiconductor layer on the first surface of the back contact battery provided in this application embodiment. Figure 4 ; Figure 7 A longitudinal sectional view of the back contact battery provided in the embodiments of this application. Figure 3 ; Figure 8 A longitudinal sectional view of the back contact battery provided in the embodiments of this application. Figure 4 ; Figure 9 A longitudinal sectional view of the back contact battery provided in the embodiments of this application. Figure 5 ; Figure 10 A schematic diagram illustrating the positional relationship of the strip-shaped recess in the back contact battery at a portion of the docking area, as provided in the embodiments of this application. Figure 1; Figure 11 A schematic diagram of the structure at the docking region in a back contact battery provided in an embodiment of this application; Figure 12 A longitudinal sectional view of the back contact battery provided in the embodiments of this application. Figure 6 ; Figure 13 A schematic diagram illustrating the positional relationship of the strip-shaped recess in the back contact battery at a portion of the docking area, as provided in the embodiments of this application. Figure 2 ; Figure 14 A longitudinal sectional view of the back contact battery provided in the embodiments of this application. Figure 7 ; Figure 15 A longitudinal sectional view of the back contact battery provided in the embodiments of this application. Figure 8 ; Figure 16 A longitudinal sectional view of the back contact battery provided in the embodiments of this application. Figure 9 ; Figure 17 A schematic diagram illustrating the positional relationship of the strip-shaped recess in the back contact battery at a portion of the docking area, as provided in the embodiments of this application. Figure 3 ; Figure 18 A schematic diagram illustrating the positional relationship of the strip-shaped recess in the back contact battery at a portion of the docking area, as provided in the embodiments of this application. Figure 4 ; Figure 19 A schematic diagram illustrating the positional relationship of the strip-shaped recess in the back contact battery at a portion of the docking area, as provided in the embodiments of this application. Figure 5 ; Figure 20 A schematic diagram illustrating the distribution of different substructures in a back contact battery provided in an embodiment of this application; Figure 21 A longitudinal sectional view of the back contact battery provided in the embodiments of this application. Figure 10 ; Figure 22 A longitudinal sectional view of the back contact battery provided in the embodiments of this application. Figure 10 one.

[0042] Reference numerals: 11 is a semiconductor substrate, 12 is a first doped semiconductor layer, 13 is a second doped semiconductor layer, 14 is a docking region, 15 is a first region, 16 is a strip-shaped recess, 17 is a strip-shaped protrusion, 18 is a substructure, 19 is a second region, 20 is a third region, 21 is a fourth region, 22 is a trench region, 23 is an extension region, 24 is a first collector electrode, 25 is a second collector electrode, 26 is a first bus electrode, 27 is a second bus electrode, 28 is a first strip-shaped portion, 29 is a second strip-shaped portion, 30 is a first connection region, 31 is a second connection region, 32 is a first interface passivation layer, 33 is a second interface passivation layer, and 34 is an insulating layer. Detailed Implementation

[0043] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of this application. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0044] The accompanying drawings show various structural schematic diagrams according to embodiments of this application. These drawings are not drawn to scale, and some details have been enlarged and may have been omitted for clarity. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0045] In the context of this application, when a layer / element is referred to as being "on top of" another layer / element, the layer / element can be directly on top of the other layer / element, or there can be an intermediate layer / element between them. Furthermore, if a layer / element is "on top of" another layer / element in one orientation, then when the orientation is reversed, the layer / element can be "below" the other layer / element. To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise expressly specified. "Several" means one or more, unless otherwise expressly specified.

[0047] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0048] Firstly, embodiments of this application provide a back-contact battery. For example... Figure 1 and Figure 2 As shown, the back-contact battery includes: a semiconductor substrate 11, a first doped semiconductor layer 12, a second doped semiconductor layer 13, a first current collector 24, and a second current collector 25. The second doped semiconductor layer 13 and the first doped semiconductor layer 12 have opposite conductivity types. The semiconductor substrate 11 includes a first surface and a second surface facing each other. The first doped semiconductor layer 12 and the second doped semiconductor layer 13 are disposed on the first surface, and an isolation region is formed between the main regions of the first doped semiconductor layer 12 and the main regions of the second doped semiconductor layer 13. Partial regions of the first doped semiconductor layer 12 and partial regions of the second doped semiconductor layer 13 are connected to form a docking region 14. A plurality of first current collectors 24 are disposed on the side of the first doped semiconductor layer 12 facing away from the semiconductor substrate 11. A plurality of second current collectors 25 are disposed on the side of the second doped semiconductor layer 13 facing away from the semiconductor substrate 11.

[0049] like Figure 1 and Figure 2 As shown, multiple first collector electrodes 24 and multiple second collector electrodes 25 extend along a first direction and are alternately distributed along a second direction.

[0050] like Figure 1 and Figure 2 As shown, a portion of the first doped semiconductor layer 12 and a portion of the second doped semiconductor layer 13 are stacked along the thickness direction of the semiconductor substrate 11 to form a docking region 14.

[0051] like Figure 1 and Figure 2 As shown, at least one of the first collector electrode 24 and the second collector electrode 25 is distributed at intervals with the docking region 14.

[0052] like Figure 1 and Figure 2As shown, a first doped semiconductor layer 12 and a second doped semiconductor layer 13 with opposite conductivity types are disposed on a first surface of the semiconductor substrate 11. Furthermore, a portion of the first doped semiconductor layer 12 and a portion of the second doped semiconductor layer 13 are connected to form a docking region 14. Within at least a portion of this docking region 14, the first doped semiconductor layer 12 and the second doped semiconductor layer 13 can form a built-in diode structure with a low reverse breakdown voltage. When the back contact battery is blocked, leakage current flows through at least a localized area of ​​the docking region 14, and through the main regions of the first doped semiconductor layer 12 and the second doped semiconductor layer 13 adjacent to the docking region 14 to the electrode outlet, reducing the reverse breakdown voltage of the back contact battery. Figures 2 to 4 As shown, this application forms a docking region 14 by stacking a first doped semiconductor layer 12 and a second doped semiconductor layer 13 with opposite conductivity types along the thickness direction of the semiconductor substrate 11. This reduces the risk of hot spots in the back contact battery while ensuring reliable leakage contact between the two. The leakage current can be controlled by adjusting the coverage area of ​​the first doped semiconductor layer 12 and the second doped semiconductor layer 13 at the top of the stack, thereby improving the applicability of the back contact battery in different application scenarios.

[0053] like Figure 1 and Figure 5 As shown, within the docking region 14, the first doped semiconductor layer 12 and the second doped semiconductor layer 13 can be in direct contact, or they can be indirectly contacted through other film layers (e.g., a second interface passivation layer or an insulating layer). Alternatively, the first doped semiconductor layer 12 and the second doped semiconductor layer 13 can form a built-in diode structure with a low reverse breakdown voltage in each region of the docking region 14, or only in a localized region of the docking region 14. An isolation region exists between the main region of the first doped semiconductor layer 12 and the main region of the second doped semiconductor layer 13. This isolation region refers to the physical insulation achieved between the main regions of the first doped semiconductor layer 12 and the main regions of the second doped semiconductor layer 13 through structures such as grooves, or through chemical film layers such as interface passivation layers or insulating layers.

[0054] From a functional perspective, the isolation region is the area used to separate the N-region from the P-region, where one of the main regions of the first doped semiconductor layer and the other of the main region of the second doped semiconductor layer roughly corresponds to the N-region.

[0055] In some embodiments, one of the N-region and P-region of the back contact battery is configured as a first doped semiconductor layer of a single conductivity type, and the other is configured as a second doped semiconductor layer of a single conductivity type. In other words, the main region of the first doped semiconductor layer is exposed outside the doped layer, such as the second doped semiconductor layer, which has a conductivity type opposite to its own, and the main region of the second doped semiconductor layer is exposed outside the first doped semiconductor layer, such as the first doped semiconductor layer, which has a conductivity type opposite to its own.

[0056] From the perspective of film layer bonding, the docking region can be formed by at least a portion of the first doped semiconductor layer extending from the main region covering a portion of the second doped semiconductor layer; and / or, at least a portion of the second doped semiconductor layer extending from the main region covering a portion of the first doped semiconductor layer; and / or, at least a portion of the first doped semiconductor layer extending from the main region extending below a portion of the second doped semiconductor layer; and / or, at least a portion of the second doped semiconductor layer extending from the main region extending below a portion of the first doped semiconductor layer.

[0057] In practical applications, such as Figures 2 to 4 As shown, at least one of the first collector electrode 24 and the second collector electrode 25 can be spaced apart from the docking region 14. This can be because only the first collector electrode 24 is spaced apart from the docking region 14, or only the second collector electrode 25 is spaced apart from the docking region 14, or both the first collector electrode 24 and the second collector electrode 25 are spaced apart from the docking region 14 to prevent short circuits.

[0058] like Figures 2 to 4 As shown, multiple first collector electrodes 24 and multiple second collector electrodes 25 can all extend along a first direction and are alternately distributed along a second direction. This arrangement enables the effective collection of charge carriers of different conductivity types.

[0059] In some embodiments, the back contact battery may further include a passivation layer. The passivation layer is disposed on the side of the first doped semiconductor layer and the second doped semiconductor layer facing away from the semiconductor substrate. At least a portion of the first current collector electrode penetrates the passivation layer and is connected to the first doped semiconductor layer. At least a portion of the second current collector electrode penetrates the passivation layer and is connected to the second doped semiconductor layer.

[0060] For example, after at least a portion of the first collector electrode penetrates the passivation layer, it may only contact the surface of the first doped semiconductor layer; and / or, after at least a portion of the second collector electrode penetrates the passivation layer, it may only contact the surface of the second doped semiconductor layer.

[0061] Alternatively, at least a portion of the first collector electrode may penetrate the passivation layer and extend into the first doped semiconductor layer along the thickness direction of the semiconductor substrate to increase the contact area between the two and reduce the contact resistance; furthermore, a certain distance may be maintained between the first collector electrode and the semiconductor substrate to reduce metal recombination losses. And / or, at least a portion of the second collector electrode may penetrate the passivation layer and extend into the second doped semiconductor layer along the thickness direction of the semiconductor substrate to increase the contact area between the two and reduce the contact resistance; furthermore, a certain distance may be maintained between the second collector electrode and the semiconductor substrate to reduce metal recombination losses.

[0062] It is understandable that since both the collector electrode (first collector electrode and second collector electrode) and the doped semiconductor layer (first doped semiconductor layer and second doped semiconductor layer) are materials that can achieve electrical conduction, the electrical connection between the collector electrode and the doped semiconductor layer can be achieved regardless of whether the collector electrode and the corresponding doped semiconductor layer are in surface contact or extend into the doped semiconductor layer along the thickness direction of the semiconductor substrate.

[0063] In some embodiments, the electrode structure of the back contact battery may include only a first current collector electrode and a second current collector electrode.

[0064] Or, for example, such as Figure 3 and Figure 4 As shown, the electrode structure of the back contact battery includes a first current collector electrode and a second current collector electrode, and may also include a first current collector electrode 26 and a second current collector electrode 27. Both the first current collector electrode 26 and the second current collector electrode 27 extend along a second direction and are alternately distributed along a first direction. Each first current collector electrode 26 is connected to at least a portion of the first current collector electrode 24. Each second current collector electrode 27 is connected to at least a portion of the second current collector electrode 25. The extension lengths of the first current collector electrode 26 and the second current collector electrode 27, as well as their specific positions on the first surface, can be set according to actual needs and are not specifically limited here.

[0065] It should be noted that since both the collector electrode (first collector electrode and second collector electrode) and the bus electrode (first bus electrode and second bus electrode) are made of materials that can achieve electrical conductivity, when the collector electrode and the corresponding bus electrode are connected, an electrical connection between the collector electrode and the bus electrode can be achieved.

[0066] This application does not specifically limit the material and conductivity type of the semiconductor substrate. For example, the semiconductor substrate can be a silicon substrate. Alternatively, the semiconductor substrate can be a germanium-silicon substrate, a germanium substrate, or a gallium arsenide substrate, or any other semiconductor material. Furthermore, the semiconductor substrate can be an N-type semiconductor substrate, a P-type semiconductor substrate, or an intrinsic semiconductor substrate.

[0067] Additionally, it can be understood that the first surface of the semiconductor substrate corresponds to the back side of the back contact battery, and the second surface of the semiconductor substrate corresponds to the front side of the back contact battery (i.e., the surface directly exposed to light).

[0068] Regarding the first and second doped semiconductor layers, in terms of conductivity type, the first doped semiconductor layer can be an N-type doped semiconductor layer, in which case the second doped semiconductor layer is a P-type doped semiconductor layer. Alternatively, the first doped semiconductor layer can also be a P-type doped semiconductor layer, in which case the second doped semiconductor layer is an N-type doped semiconductor layer.

[0069] In terms of materials, the first and / or second doped semiconductor layers can be made of any semiconductor material such as silicon, germanium-silicon, germanium, or gallium arsenide. In terms of the arrangement of matter, the crystal phase of the first and / or second doped semiconductor layers can be amorphous, microcrystalline, nanocrystalline, single-crystal, or polycrystalline. The materials of the first and second doped semiconductor layers can be the same or different.

[0070] For example, both the first and second doped semiconductor layers are doped crystalline silicon layers or doped amorphous silicon layers. Another example is that one of the first and second doped semiconductor layers is a doped crystalline silicon layer, and the other is a doped amorphous silicon layer.

[0071] In terms of setting location, such as Figure 1 As shown, the first doped semiconductor layer 12 can be directly disposed on the semiconductor substrate 11. Alternatively, as... Figure 5 As shown, the back contact battery may further include a first interface passivation layer 32, which is located at least between the first doped semiconductor layer 12 and the semiconductor substrate 11. With this configuration, the passivated contact structure formed by the first interface passivation layer 32 and the first doped semiconductor layer 12 has excellent interface passivation effect and can achieve selective collection of charge carriers, reducing the carrier recombination rate in the corresponding region of the first surface of the semiconductor substrate 11 and improving the conversion efficiency of the back contact battery. The material and thickness of the first interface passivation layer 32 can be set according to the material of the first doped semiconductor layer 12 and actual needs, and are not specifically limited here. For example, when the material of the first doped semiconductor layer is doped polycrystalline silicon, the first interface passivation layer is a tunneling passivation layer. Another example: when the material of the first doped semiconductor layer includes at least one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon, the first interface passivation layer is an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, an intrinsic nanocrystalline silicon layer, or a mixture of the above three.

[0072] As for the second doped semiconductor layer, such as Figure 1As shown, the second doped semiconductor layer 13 can be directly disposed on the semiconductor substrate 11. Alternatively, as... Figure 5 As shown, the back contact cell may further include a second interface passivation layer 33. The second interface passivation layer 33 is located at least between the second doped semiconductor layer 13 and the semiconductor substrate 11 to reduce the carrier recombination rate in the corresponding region of the first surface of the semiconductor substrate 11 and improve the photoelectric conversion efficiency of the back contact cell. The principle for selecting the material of the second interface passivation layer 33 can refer to the principle for determining the material of the first interface passivation layer 32 described above, and will not be repeated here.

[0073] It should be understood that, as Figure 1 As shown, a portion of the first doped semiconductor layer 12 and a portion of the second doped semiconductor layer 13 are connected to form a docking region 14. This can refer to a direct connection between a portion of the first doped semiconductor layer 12 and a portion of the second doped semiconductor layer 13; or, as... Figure 5 , Figure 7 , Figure 8 and Figure 9 As shown, it can also refer to the indirect connection between a portion of the first doped semiconductor layer 12 and a portion of the second doped semiconductor layer 13, for example, through a film layer, or through a first interface passivation layer 32 or a second interface passivation layer 33.

[0074] When the back contact battery also includes a first interface passivation layer and a second interface passivation layer, the materials of the first interface passivation layer and the second interface passivation layer can be the same or different.

[0075] For example, both the first doped semiconductor layer and the second doped semiconductor layer are doped crystalline silicon layers, and both the first interface passivation layer and the second interface passivation layer are tunneling oxide layers.

[0076] For example, both the first doped semiconductor layer and the second doped semiconductor layer are doped amorphous silicon layers, and both the first interface passivation layer and the second interface passivation layer are intrinsic amorphous silicon layers.

[0077] For example: the first doped semiconductor layer is a doped crystalline silicon layer, and the first interface passivation layer is a tunneling oxide layer. The second doped semiconductor layer is a doped amorphous silicon layer, and the second interface passivation layer is an intrinsic amorphous silicon layer.

[0078] In terms of the scope of formation, such as Figures 1 to 5As shown, in the first surface of the semiconductor substrate 11, the region below the mating region 14 is defined as the first region 15; the region corresponding to the main region of the first doped semiconductor layer 12 is defined as the second region 19; and the region corresponding to the main region of the second doped semiconductor layer 13 is defined as the third region 20. The positional relationship between the first region 15, the second region 19, and the third region 20, as well as their ranges in the first surface, can be determined based on the positional relationship between the first doped semiconductor layer 12 and the second doped semiconductor layer 13 in the mating region 14, and actual requirements, and are not specifically limited here.

[0079] For example, such as Figures 2 to 4 As shown, the first surface of the semiconductor substrate 11 may include a second region 19 and a third region 20 spaced apart, and a fourth region 21 located between the second region 19 and the third region 20. Furthermore, a portion of the first doped semiconductor layer 12 extends from above the second region 19 to above a portion of the fourth region 21, and / or a portion of the second doped semiconductor layer 13 extends from above the third region 20 to above a portion of the fourth region 21, forming a mating region 14. In the fourth region 21, the area below the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 extending from the main region is an extension region 23, and the area without the first doped semiconductor layer 12 and the second doped semiconductor layer 13 is a trench region 22 (the trench region 22 is a type of isolation region).

[0080] like Figures 2 to 4 As shown, the docking region 14 can be considered as the region where the first doped semiconductor layer 12 and the second doped semiconductor layer 13 are connected. The docking region 14 is usually formed by one or both of the first doped semiconductor layer 12 and the second doped semiconductor layer 13 extending from the main distribution region and forming a direct or indirect connection with each other. Therefore, the main region of the first doped semiconductor layer 12 and the main region of the second doped semiconductor layer 13 can be considered as the region other than the docking region 14 and the corresponding first doped semiconductor layer 12 and / or second doped semiconductor layer 13 on the extension region 23.

[0081] In some embodiments, such as Figures 2 to 4 As shown, a portion of one of the first doped semiconductor layer 12 and the second doped semiconductor layer 13 may not only extend to the extension region 23, but may also extend from the extension region 23 to cover a portion of the other (or extend further into the area below the other). Specifically, along the thickness direction of the semiconductor substrate 11, within the mating region, the first doped semiconductor layer 12 may be located below the second doped semiconductor layer 13, or the second doped semiconductor layer 13 may be located below the first doped semiconductor layer 12.

[0082] Additionally, within the docking area, such as Figure 7As shown, an insulating layer 34 may be disposed between the first doped semiconductor layer 12 and the second doped semiconductor layer 13. The insulating layer 34 may be disposed only between the first doped semiconductor layer 12 and the second doped semiconductor layer along the thickness direction of the semiconductor substrate 11. In this case, the lower part of the first doped semiconductor layer 12 and the lower part of the second doped semiconductor layer 13 may be connected to the other part extending and covering the sidewall through a sidewall, and / or, as shown... Figure 8 As shown, a leakage path can be provided in the insulating layer 34, and the first doped semiconductor layer 12 and the second doped semiconductor layer 13 can be connected at least through the leakage path; or, as... Figure 9 As shown, the insulating layer 34 is not only disposed between the first doped semiconductor layer 12 and the second doped semiconductor layer 13 along the thickness direction of the semiconductor substrate 11, but can also be disposed between the first doped semiconductor layer 12 and the second doped semiconductor layer 13 in a direction parallel to the first surface. In this case, a leakage channel is provided in the insulating layer 34, and the first doped semiconductor layer 12 and the second doped semiconductor layer 13 are connected through the leakage channel. Alternatively, as... Figure 1 As shown, in the docking area, the first doped semiconductor layer 12 and the second doped semiconductor layer 13 may not have an insulating layer. In this case, the first doped semiconductor layer 12 and the second doped semiconductor layer 13 can be connected at the stacking interface in the longitudinal direction (i.e., the thickness direction of the semiconductor substrate 11) parallel to the first surface direction. They can be connected or electrically insulated at the contact interface on the side.

[0083] Alternatively, in other embodiments, such as Figure 9 As shown, a portion of each of the first doped semiconductor layer 12 and the second doped semiconductor layer 13 may extend at least to the extension region 23, and the first doped semiconductor layer 12 and the second doped semiconductor layer 13 may be stacked along the thickness direction of the semiconductor substrate 11 at least on the extension region 23 to form a docking region.

[0084] It is worth noting that the risk of hot spots on the back contact battery can be controlled by adjusting the setting range of the insulating layer between the first doped semiconductor layer and the second doped semiconductor layer in the docking area, and / or by adjusting the number and / or size of the leakage channels.

[0085] The width of the isolation zone can be set according to actual needs.

[0086] For example, the width of at least one isolation region can be greater than or equal to 20 μm and less than or equal to 1000 μm. For instance, the width of the isolation region can be 20 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 300 μm, 500 μm, 800 μm, or 1000 μm, etc. Optionally, the width of at least one isolation region can be greater than or equal to 50 μm and less than or equal to 300 μm. This setting can prevent excessively high carrier recombination rates due to an excessively small isolation region width, ensuring high conversion efficiency of the back contact cell in the forward voltage region. Additionally, it can prevent low carrier collection efficiency of the first and second doped semiconductor layers in the isolation region due to an excessively large isolation region width; secondly, in some cases, the width of the isolation region can affect the width of the docking region. Therefore, when the width of the isolation region is within the above range, it can also prevent the width of the docking region from being too large due to the excessive width of the isolation region. This is beneficial for controlling the leakage contact area between the first doped semiconductor layer and the second doped semiconductor layer in the docking region, and controlling the leakage current.

[0087] In addition, when the first surface includes a second region, a third region, and a fourth region, the relative sizes of the surface heights of the second, third, and fourth regions can be set according to the positional relationship between the first doped semiconductor layer and the second doped semiconductor layer at the docking area, as well as actual requirements.

[0088] In some embodiments, the second side relative to the semiconductor substrate, such as Figure 1 , Figure 21 and Figure 22 As shown, the surfaces of the second region 19 and the third region 20 can have a height difference. When the trench region 22 is provided, the surfaces of both the second region 19 and the third region 20 are higher than the surface of the trench region 22. For example, it can be configured such that, relative to the second surface of the semiconductor substrate, the surface of the second region 19 is higher than the surface of the third region 20, and the surface of the third region 20 is higher than the surface of the trench region 22. Because during the fabrication of the first doped semiconductor layer 12 and the second doped semiconductor layer 13, dopants may enter the surfaces of the second region 19 and the third region 20 to form doped layers, by setting the surface of the second region 19 to be higher than the surface of the third region 20, and the surface of the third region 20 to be higher than the surface of the trench region 22, the interconnection between doped layers of different conductivity types on the first surface of the semiconductor substrate can be cut off, avoiding the formation of short circuits. Secondly, when the second doped semiconductor layer 13 extends from the extension region to the first doped semiconductor layer 12 located in the docking region, the lower surface height of the extension region compared to the surface height of the second region also helps to allow the side of the first doped semiconductor layer 12 at the docking region to connect with the second doped semiconductor layer 13, reducing the risk of hot spots on the back contact battery.

[0089] In some embodiments, such as Figure 1, Figure 21 and Figure 22 As shown, at least one of the surfaces of the second region 19 and the third region 20, relative to the second side of the semiconductor substrate, is flush with the surface of the extension region 23. This arrangement reduces fabrication steps, increases production efficiency, and reduces battery damage.

[0090] In some embodiments, the second side relative to the semiconductor substrate, such as Figure 21 As shown, the surface of the extension region 23 is flush with the surface of the first region 15, or the surface of the extension region 23 is lower than the surface of the first region 15. When the surface of the extension region 23 is flush with the surface of the first region 15 (i.e., relative to the second surface of the semiconductor substrate, the height of the surface of the extension region 23 is equal to the height of the surface of the first region 15), the surface of the second region 19 can be flush with the surface of the extension region 23, and the surface of the third region 20 is lower than the surface of the first region 15. This arrangement allows for sufficient connection between the sides of the first doped semiconductor layer 12 and the second doped semiconductor layer 13 in the mating region 14. When the surface of the extension region 23 is lower than the surface of the first region 15 (i.e., relative to the second surface of the semiconductor substrate, the height of the surface of the extension region 23 is lower than the height of the surface of the first region 15), this arrangement also allows for sufficient connection between the sides of the first doped semiconductor layer 12 and the second doped semiconductor layer 13 in the mating region 14.

[0091] For example: Figures 2 to 4 As shown, when the first surface includes a second region 19, a third region 20, and a fourth region 21, and a portion of the second doped semiconductor layer 13 covers the extension region 23 and a portion of the first doped semiconductor layer 12, the first region 15 is the portion located below the stacked first doped semiconductor layer 12 and the second doped semiconductor layer 13. The surface heights of the first region 15 and the second region 19 can be the same, and the surface height of the second region 19 can be greater than the surface heights of the third region 20 and the fourth region 21. The surface height of the third region 20 can be the same as the surface height of the extension region 23 in the fourth region 21, and the surface height of the third region 20 can be greater than the surface height of the trench region 22 in the fourth region 21.

[0092] In terms of the location of the docking area, such as Figure 2 As shown, the first doped semiconductor layer 12 may include a plurality of first stripes, and the second doped semiconductor layer 13 may include a plurality of second stripes. The plurality of first stripes and the plurality of second stripes may extend along a first direction and be alternately distributed along a second direction. The first direction and the second direction intersect. In this case, the mating region 14 may be at least a portion of the edge region of the first stripes and / or the second stripes along the second direction.

[0093] The first direction and the second direction can be any two different directions that are parallel to the first surface and intersect. Optionally, the first direction and the second direction can be perpendicular.

[0094] like Figure 2 As shown, in the case where the back contact battery includes a plurality of first current collectors 24 and a plurality of second current collectors 25, the first current collectors 24 may be disposed on the first strip portion 28 included in the first doped semiconductor layer 12, and the second current collectors 25 may be disposed on the second strip portion 29 included in the second doped semiconductor layer 13.

[0095] like Figure 3 and Figure 4 As shown, the first doped semiconductor layer 12 may further include multiple rows of first connection regions 30, and the second doped semiconductor layer 13 may further include multiple rows of second connection regions 31. The first connection regions 30 and second connection regions 31 are alternately distributed along a first direction. Each row of first connection regions 30 includes multiple first connection regions 30 spaced apart along a second direction. Each first connection region 30 is at least disposed between two adjacent first strip-shaped portions and is connected to the first strip-shaped portion. Each row of second connection regions 31 includes multiple second connection regions 31 spaced apart along a second direction. Each second connection region 31 is at least disposed between two adjacent second strip-shaped portions and is connected to the second strip-shaped portion.

[0096] The first connecting area may be provided only between two adjacent first strips, or at least one first connecting area may be provided on the outer side of the first strip located on the outer side along the second direction. Alternatively, a first connecting area may be provided between every two adjacent first strips, or a first connecting area may be provided between some of the two adjacent first strips, with no first connecting area provided between some of the two adjacent first strips.

[0097] As for the second connecting area, the second connecting area may be provided only between two adjacent second strips, or at least one second connecting area may be provided on the outer side of the second strip located on the outer side along the second direction. Alternatively, a second connecting area may be provided between every two adjacent second strips, or a second connecting area may be provided between some of the two adjacent second strips, with no second connecting area provided between some of the two adjacent second strips.

[0098] like Figure 3 and Figure 4 As shown, when the first doped semiconductor layer 12 further includes a first connection region 30 and the second doped semiconductor layer 13 further includes a second connection region 31, the docking region 14 may be disposed in the edge region of the first strip portion and / or the second strip portion, and / or, in at least a portion of the edge region of the first connection region 30 and / or the second connection region 31 along the first direction.

[0099] like Figure 3 and Figure 4As shown, when the first doped semiconductor layer 12 further includes a first bus electrode 26 and a second bus electrode 27, the first bus electrode 26 may be disposed on the first connection region 30 and the first strip portion 28 connected to the first connection region 30. The second bus electrode 27 may be disposed on the second connection region 31 and the second strip portion 29 connected to the second connection region 31.

[0100] Alternatively, the first connection area may not be provided below the first bus electrode, and the first bus electrode may be isolated from the second doped semiconductor layer by an insulating structure such as insulating glue; the second connection area may not be provided below the second bus electrode, and the second bus electrode may be isolated from the first doped semiconductor layer by an insulating structure such as insulating glue.

[0101] For example, such as Figure 5 and Figure 10 As shown, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 may be provided in the first surface of the semiconductor substrate 11. Furthermore, the strip-shaped recess 16 and / or strip-shaped protrusion 17 extend from one side of at least one first region 15 that is distributed opposite to each other in the width direction to the other side. In this case, when at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 is provided in the first surface, and the strip-shaped recess 16 and / or strip-shaped protrusion 17 extend from one side of the two sides of the first region 15 located below the docking region 14 that are distributed opposite each other in the width direction to the other side, on the one hand, the surface of the first region 15 has an uneven undulating morphology, which can increase the specific surface area of ​​the first region 15; correspondingly, the first doped semiconductor layer 12 and the second doped semiconductor layer 13 constituting the docking region 14 and formed on the first region 15 by the deposition process also have a large coverage area, which is beneficial to increase the leakage contact area between the first doped semiconductor layer 12 and the second doped semiconductor layer 13 in the docking region 14, thereby increasing the leakage current, reducing the hot spot risk of the back contact battery, and improving the burn-out resistance of the back contact battery. On the other hand, the strip-shaped recess 16 and / or the strip-shaped protrusion 17 extend across the first region 15 along the width direction of the first region 15. Correspondingly, the first doped semiconductor layer 12 and the second doped semiconductor layer 13 located on the strip-shaped recess 16 and / or the strip-shaped protrusion 17 also extend along the width direction of the first region 15. This part of the first doped semiconductor layer 12 and this part of the second doped semiconductor layer 13 form a strip-shaped fast channel for charge carriers, which is conducive to leakage current transmission, further reduces the risk of hot spots in the back contact battery, and further improves the burn-out resistance of the back contact battery.

[0102] In the actual manufacturing process, before forming the first and second doped semiconductor layers, corresponding marks can be formed on the semiconductor substrate corresponding to the strip-shaped protrusions or recesses using methods such as scribing. The scribing method can be laser scribing, physical scribing using a material with a certain hardness such as diamond wire, or chemical etching through a chemical reaction. For example, when using laser scribing and a strip-shaped recess is provided on the first surface, a groove is prepared at a predetermined position on the first surface of the semiconductor substrate using a laser. The laser wavelength can be ultraviolet, visible (green or red), or infrared laser for groove placement. Because different wavelengths of laser correspond to different energies, the depth of the groove obtained after laser scribing is also different. After preparing the strip-shaped recess based on the groove, the depth of the recess is also different. Therefore, the type of laser can be determined according to the depth requirements of the desired strip-shaped recess. The specific irradiation energy, spot size, overlap rate, and other parameters of the laser can be determined according to the depth and width requirements of the desired strip-shaped recess. For example, the laser irradiation power can be selected from 2W to 100W. This setting can prevent excessive laser power from causing thermal damage or making it difficult to control the process window, and can also prevent excessive laser power from causing excessively long process times or shallow etching depths. As another example, when using diamond wire for physical scribing, at least the diamond wire should make contact with the semiconductor substrate, and the surface of the semiconductor substrate corresponding to the first region should be pre-treated to form corresponding depressions or protrusions (e.g., deep line marks) in the corresponding strip-shaped protrusions or depressions. For example, when using chemical scribing with chemical reactions, under the protection of the corresponding mask layer (such as photoresist mask, silicon nitride mask, etc.), at least the chemical reaction solution and the semiconductor substrate can be in partial contact. The surface of the semiconductor substrate corresponding to the first region is pretreated to form the corresponding depression or protrusion morphology in the corresponding strip-shaped protrusion or depression. The degree of protrusion or depression of the strip-shaped protrusion or depression can be controlled by controlling the type and concentration of the chemical reaction solution and the reaction time. The number or width of the strip-shaped protrusion or depression can be controlled by controlling the reaction position (such as controlling the mask pattern of the mask layer).

[0103] Marks obtained through methods such as scratching (e.g., laser scratching or diamond wire scratching) may contain material damage that needs to be removed, or there may be a need to further change the depth of depressions or the height of protrusions, or to further change the distribution density of depressions or protrusions. Scraping can be followed by etching processes, such as chemical etching like wet etching. It is understandable that, when combined with subsequent etching processes, the depth of depressions or the height of protrusions obtained through scratching will be greater than the depth or height obtained through etching.

[0104] To simplify the manufacturing process, we can adjust and utilize existing back-contact battery manufacturing processes to achieve the technical solution of this application. For example, using diamond wire cutting to obtain a semiconductor substrate with wire marks, during the process of cutting the semiconductor rod to form the semiconductor substrate using diamond wire or other cutting lines, the depth of the subsequently obtained strip-shaped recesses or the height of the strip-shaped protrusions, as well as the width of the strip-shaped recesses and / or protrusions, can be adjusted by setting the line width of the cutting lines, setting the size and density of the diamond particles, and the extension angle of the strip-shaped recesses and / or protrusions in the first region can be controlled by adjusting the wire tension. Another example is using a wet etching step (this wet etching step can be a wet etching step for preparing a textured surface such as a textured surface, or a wet etching step for patterning the first doped semiconductor layer and / or the second doped semiconductor layer, etc.) to chemically etch the marks obtained by the scribing to obtain strip-shaped recesses and / or protrusions with depth, width, or height that meet actual requirements.

[0105] Understandably, during the design phase, we rationally plan to ensure that all or part of the mating areas formed by connecting certain regions of the first and second doped semiconductor layers correspond to a certain number of strip-shaped recesses and / or strip-shaped protrusions. This can be achieved by matching the positions of the strip-shaped recesses and / or protrusions with the patterned reserved areas of the doped semiconductor layers: after pre-forming the corresponding recesses or protrusions in parts of the strip-shaped protrusions or recesses, the first surface of the semiconductor substrate is planarized, such as through shallow etching or polishing, so that the pre-formed recesses or protrusions on the original semiconductor substrate form strip-shaped recesses and / or strip-shaped protrusions with a height difference from other areas. In the subsequent film manufacturing process, alignment of the semiconductor substrate can be achieved by gripping points, edges, or directly gripping the alignment marks on the battery. Next, following the sequential deposition of the first or second doped semiconductor layer covering the first surface, selective etching of the first or second doped semiconductor layer is performed using processes such as laser etching or chemical etching, based on the alignment information. Before selective etching, laser etching patterns and screen printing morphology are set to ensure that at least the reserved docking areas and the preset strip-shaped recesses and / or strip-shaped protrusions are aligned. That is, according to our pre-set matching relationship, the docking areas are aligned with the strip-shaped recesses and / or strip-shaped protrusions; this also ensures that the first and / or second doped semiconductor layers covering the strip-shaped recesses and / or strip-shaped protrusions also have a certain undulating morphology, improving the burn-out resistance of the back contact battery. Matching between the strip-shaped recesses and / or protrusions and the mating area can also be achieved by designing the distribution density of the strip-shaped recesses and / or protrusions, and / or by designing the spacing between adjacent strip-shaped recesses and / or protrusions. For example, increasing the distribution density of the strip-shaped recesses and / or protrusions and / or decreasing the spacing between adjacent strip-shaped recesses and / or protrusions can make at least one strip-shaped recess and / or protrusion pass through at least part of the mating area. For example, if the length of a docking area is greater than the distance between two adjacent strip-shaped recesses and / or strip-shaped protrusions along the direction extending from the isolation area, then at least one strip-shaped recess and / or strip-shaped protrusion will inevitably pass through the docking area; when the length of a docking area along the direction extending from the isolation area is more than twice the distance between two adjacent strip-shaped recesses and / or strip-shaped protrusions, then at least one strip-shaped recess and / or strip-shaped protrusion will inevitably pass through the docking area, and it is even possible that two strip-shaped recesses and / or strip-shaped protrusions will pass through the docking area.

[0106] It is understandable that the one-dimensional size and distribution of the pre-formed depressions or protrusions, as well as the relevant parameters for controlling the leveling process, need to be set reasonably. As for the specific range of the above parameters, those skilled in the art can adjust them according to actual needs.

[0107] It should be noted that, although, to reduce the risk of hot spots on the back contact battery, the depth, height, width, and distribution density of the initially formed grooves, protrusions, and grooves or protrusions on the semiconductor substrate are adjusted through methods such as scribing, as described above, and the degree of readjustment of the depth, height, width, and distribution density of the initially formed grooves, protrusions, and grooves or protrusions by wet etching is controlled, as well as the length of the docking area is controlled, so that the docking area can be set above the strip-shaped recesses and / or strip-shaped protrusions, in other words, as much as possible, strip-shaped recesses and / or strip-shaped protrusions are set in the first area corresponding to more docking areas, there may still be some errors in the actual manufacturing process due to manufacturing errors or the inability to achieve 100% etching control. For example, the degree of etching in a local area of ​​the first surface of the semiconductor substrate may be too high, making it impossible or difficult to observe the strip-shaped recesses and / or strip-shaped protrusions on the surface of that area, so that the strip-shaped recesses and / or strip-shaped protrusions are not set in that area. That is, there may be docking areas located in that part that are not set on the strip-shaped recesses and / or strip-shaped protrusions. The actual situation is not as perfect as the initial design, but as long as there is an area in the back contact battery that satisfies the technical solution of this application, the back contact battery should be considered to fall within the scope of this application.

[0108] The size of the docking area can be set according to actual needs.

[0109] For example, the length of at least one mating region can be greater than or equal to 20 μm and less than or equal to 1000 μm. For instance, the length of at least one mating region can be 20 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 300 μm, 600 μm, 800 μm, or 1000 μm, etc. This configuration prevents the mating region from being too short, thus ensuring high alignment accuracy between the mating region formed on the first surface of the semiconductor substrate and the strip-shaped recesses and / or strip-shaped protrusions on the first surface of the semiconductor substrate. This reduces the risk of hot spots on the back contact battery while lowering the manufacturing process difficulty.

[0110] For example, the length of at least one mating area is greater than the distance between two adjacent strip-shaped recesses and / or strip-shaped protrusions. This arrangement helps ensure that the mating area can be positioned above at least one strip-shaped recess or strip-shaped protrusion, reducing the risk of hot spots on the back contact battery.

[0111] In addition, along the thickness direction of the semiconductor substrate, the thickness of the portion of the first doped semiconductor layer and / or the second doped semiconductor layer located on the side of the strip-shaped recess and / or the strip-shaped protrusion can be equal to the thickness of the rest of itself.

[0112] Or, such as Figure 11As shown, along the thickness direction of the semiconductor substrate 11, the thickness L1 of the portion of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 located on the side of the strip-shaped recess 16 and / or the strip-shaped protrusion 17 can also be greater than the thickness L2 of the rest of its portion (taking the first doped semiconductor layer 12 located at the bottom as an example). Figure 11 The dashed arrow indicates the thickness of the first doped semiconductor layer 12 on the side, and the solid arrow indicates the thickness of the remaining portions. This arrangement enhances the conductivity of the portions of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 located on the sides of the strip-shaped recess 16 and / or the strip-shaped protrusion 17, reducing the transport resistance of these portions. This creates a fast channel for charge carriers while avoiding the increase in parasitic absorption caused by overall thickening, ultimately further reducing the risk of hot spots on the back contact battery.

[0113] It should be noted that the remaining portions of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 refer to the portions of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 located at the bottom of the strip-shaped recess 16, the portions located at the top of the strip-shaped protrusion 17, and the portions located on the surfaces of the first surface where the strip-shaped recess 16 and the strip-shaped protrusion 17 are not provided. Furthermore, the thickness of the portions of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 located on the sides of the strip-shaped recess 16 and / or the strip-shaped protrusion 17 can be obtained by averaging the thicknesses along the thickness direction of the semiconductor substrate 11 at at least three different locations within the portions of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 located on the sides of the strip-shaped recess 16 and / or the strip-shaped protrusion 17. The thickness of the remaining portions can be obtained by averaging the thicknesses along the thickness direction of the semiconductor substrate 11 at at least three different locations corresponding to the remaining portions of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13.

[0114] The specific dimensions of the thickness L1 of the first doped semiconductor layer and / or the second doped semiconductor layer located on the side of the strip-shaped recess and / or the strip-shaped protrusion, and the thickness L2 of the remaining portion, and the difference between the two, can be determined based on the actual needs of the back contact battery, such as conversion efficiency and hot spot risk, in the actual application scenario.

[0115] For example, the ratio of L2 to L1 is greater than or equal to 1.05 and less than 5. For instance, the ratio of L2 to L1 can be 1.05, 1.06, 1.1, 1.2, 1.5, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, or 4.9, etc. Optionally, the ratio of L2 to L1 can be greater than or equal to 1.1 and less than or equal to 3. This configuration, when the ratio of L2 to L1 is within the aforementioned range, prevents L2 from becoming too large and / or L1 from becoming too small due to an excessively large ratio. This helps ensure that the portions of the first and / or second doped semiconductor layers located on the sides of the strip-shaped recesses and / or protrusions have high conductivity, facilitating the formation of fast carrier channels. Furthermore, it avoids increased parasitic absorption in the remaining portions of the first and / or second doped semiconductor layers due to an excessively large L2, improving the operating performance of the back contact battery. Additionally, it prevents L2 from becoming too small and / or L1 from becoming too large due to an excessively small ratio of L2 to L1. This helps ensure good field passivation in the remaining portions of the first and / or second doped semiconductor layers and helps control the thickness of the portions of the first and / or second doped semiconductor layers on the sides of the strip-shaped recesses and / or protrusions within an appropriate range, preventing excessive leakage current and ensuring high conversion efficiency of the back contact battery in the forward voltage region.

[0116] For example, the difference between L2 and L1 is greater than or equal to 25 nm and less than 800 nm. For instance, the difference between L2 and L1 can be 25 nm, 30 nm, 35 nm, 40 nm, 50 nm, 80 nm, 100 nm, 200 nm, 300 nm, 500 nm, 600 nm, or 790 nm, etc. Optionally, the difference between L2 and L1 is greater than or equal to 25 nm and less than or equal to 500 nm. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect when the ratio of L2 to L1 is greater than or equal to 1.05 and less than 5, as described above.

[0117] Furthermore, the width direction of the first region can be determined based on the formation location of the mating region and the relative positional relationship between the first doped semiconductor layer and the second doped semiconductor layer within the mating region. The width of the first region refers to the direction spanning the first doped semiconductor layer, the isolation region, and the second doped semiconductor layer. In some embodiments, the width of the first region also refers to the arrangement direction of a portion of the second region and a portion of the third region adjacent to the first region.

[0118] like Figures 2 to 4As shown, the width direction of the first region 15 can be the arrangement direction of a portion of the first doped semiconductor layer 12 and a portion of the second doped semiconductor layer 13 adjacent to the mating region 14. For example, when the mating region 14 is located within at least a portion of the edge region of the first strip and / or the second strip along the second direction, the width direction of the first region 15 is parallel to the second direction. As another example, when the mating region 14 is located within at least a portion of the edge region of the first connection region 30 and / or the second connection region 31 along the first direction, the width direction of the first region 15 is parallel to the first direction.

[0119] As for the shape and size of the strip-shaped recesses and strip-shaped protrusions, they can be set according to actual needs, and no specific limitations are made here.

[0120] For example, the width of at least one strip-shaped recess and / or strip-shaped protrusion can be greater than or equal to 200 nm and less than or equal to 80 μm. For instance, the width of at least one strip-shaped recess and / or strip-shaped protrusion can be 200 nm, 300 nm, 500 nm, 1 μm, 2 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, or 80 μm, etc. Optionally, the width of at least one strip-shaped recess and / or strip-shaped protrusion can be greater than or equal to 5 μm and less than or equal to 50 μm. The width of at least one strip-shaped recess and / or strip-shaped protrusion can be greater than or equal to 10 μm and less than or equal to 40 μm. This configuration prevents the difficulty of depositing the first doped semiconductor layer and / or the second doped semiconductor layer within the strip-shaped recess and / or protrusion due to excessively small widths. It ensures good deposition quality and high coverage of the first and / or second doped semiconductor layers within the strip-shaped recess and / or protrusion, facilitating a larger leakage contact area between the first and second doped semiconductor layers in the mating region and reducing the risk of hot spots. Furthermore, it prevents the mating region from becoming excessively large due to excessively large widths of the strip-shaped recess and / or protrusion, helping to control the leakage current within an appropriate range and ensuring high conversion efficiency of the back contact battery in the forward voltage region.

[0121] For example, the depth of at least one strip-shaped recess is greater than or equal to 50 nm and less than or equal to 30 μm. This configuration, with the depth of at least one strip-shaped recess within the aforementioned range, prevents the increase in the thickness of the first and second doped semiconductor layers on the side of the strip-shaped recess from being too small, and also prevents a small increase in the area of ​​the side of the first and second doped semiconductor layers corresponding to the strip-shaped recess. This is beneficial for increasing the conductivity of the portion of the first and second doped semiconductor layers on the side of the strip-shaped recess, as well as their leakage contact area, reducing the risk of hot spots in the back contact battery. A recess depth greater than 30 μm will affect the flatness of the semiconductor substrate, and consequently the flatness of the doped semiconductor layers (including the first and second doped semiconductor layers), and / or the passivation layer, and / or the electrodes (including the first and second current collector electrodes), affecting the fabrication effect and ultimately the battery efficiency. In some cases, the depth of at least one strip-shaped recess can be greater than or equal to 50 nm and less than or equal to 5 μm, ensuring the flatness of the film deposited on the semiconductor substrate is within a certain range. In other cases, the depth of at least one strip-shaped recess can be greater than or equal to 1 μm and less than or equal to 20 μm, further increasing the conductivity of the portions of the first and second doped semiconductor layers on the side of the strip-shaped recess, as well as their leakage contact area, reducing the risk of hot spots on the back contact battery. Of course, it is understandable that the depth of the strip-shaped recess can also be selected based on the thickness of the first and second doped semiconductor layers. For example, if the thickness of the first and / or second doped semiconductor layers is 100 nm to 500 nm, a depth of at least one strip-shaped recess can be selected to be greater than or equal to 60 nm and less than or equal to 3 μm, thus balancing the effects of the above two aspects. Alternatively, the depth of the strip-shaped recess can be selected based on the number of strip-shaped recesses, such as a depth of at least one strip-shaped recess greater than or equal to 1 μm and less than or equal to 20 μm. For a depth of 30μm, a matching scheme can be chosen where some or all of the first regions correspond to one strip-shaped recess. Of course, the greater the recess depth, the fewer the number of first regions with strip-shaped recesses. For example, the recess depth corresponding to at least one strip-shaped recess can be greater than or equal to 50nm and less than or equal to 3μm. A matching scheme can be chosen where some or all of the first regions correspond to one or more strip-shaped recesses. Of course, the smaller the recess depth, the more first regions with strip-shaped recesses and / or the more strip-shaped recesses are set in a single first region. This can also take into account the effects of the above two aspects.

[0122] Optionally, the depth of at least one strip-shaped recess can be greater than or equal to 100 nm and less than or equal to 30 μm.

[0123] For example, the height of at least one strip-shaped protrusion is greater than or equal to 50 nm and less than or equal to 30 μm. The beneficial effect in this case can be referenced from the previously described principle of the beneficial effect of at least one strip-shaped recess having a depth greater than or equal to 50 nm and less than or equal to 30 μm, which will not be repeated here. In some cases, the height of at least one strip-shaped protrusion can be greater than or equal to 50 nm and less than or equal to 5 μm, ensuring the flatness of the film deposited on the semiconductor substrate is within a certain range. In other cases, the height of at least one strip-shaped protrusion can be greater than or equal to 1 μm and less than or equal to 20 μm, further increasing the conductivity of the portions of the first and second doped semiconductor layers on the side of the strip-shaped protrusion, as well as their leakage contact area, reducing the risk of hot spots on the back contact battery. Of course, it is understandable that the protrusion height corresponding to the strip-shaped protrusion can also be selected based on the thickness of the first doped semiconductor layer and the second doped semiconductor layer. For example, if the thickness of the first doped semiconductor layer and / or the second doped semiconductor layer is 100nm to 500nm, the protrusion height corresponding to at least one strip-shaped protrusion can be greater than or equal to 60nm and less than or equal to 3μm, thus achieving the desired effect in both aspects. Alternatively, the protrusion height corresponding to the strip-shaped protrusion can be selected based on the number of strip-shaped protrusions. For example, the protrusion height corresponding to at least one strip-shaped protrusion can be greater than or equal to 1μm and less than or equal to 3μm. For a depth of 30μm, a matching scheme can be chosen where some or all of the first regions correspond to one strip-shaped protrusion. Of course, the greater the protrusion height, the fewer the number of first regions with strip-shaped protrusions. For example, the protrusion height corresponding to at least one strip-shaped protrusion can be greater than or equal to 50nm and less than or equal to 3μm. A matching scheme can be chosen where some or all of the first regions correspond to one or more strip-shaped protrusions. Of course, the smaller the protrusion height, the more first regions with strip-shaped protrusions and / or the more strip-shaped protrusions are set in a single first region. This can also take into account the effects of the above two aspects.

[0124] For example, the depth of at least one strip-shaped recess in one portion of the first region is greater than the depth of at least one strip-shaped recess in another portion of the first region; and / or at least one first region includes two types of strip-shaped recesses with different depths. By combining strip-shaped recesses of different depths, the hot spot prevention effect can be optimized, and a better configuration can be obtained according to the requirements. For example, batteries with high hot spot prevention requirements can have more strip-shaped recesses with larger depths, while batteries with general hot spot prevention requirements can appropriately increase the proportion of strip-shaped recesses with smaller depths.

[0125] For example, the height of at least one strip-shaped protrusion in one portion of the first region is greater than the height of at least one strip-shaped protrusion in another portion of the first region; and / or at least one first region includes two types of strip-shaped protrusions with different heights. By combining strip-shaped protrusions with different heights, the hot spot prevention effect can be optimized, and a better configuration can be obtained according to needs. For example, batteries with high hot spot prevention requirements can have more strip-shaped protrusions with larger protrusion heights, while batteries with general hot spot prevention requirements can appropriately increase the proportion of strip-shaped protrusions with smaller protrusion heights.

[0126] In practical applications, the strip-shaped recess can be a groove structure with relatively flat sidewalls, and the strip-shaped protrusion can be a boss-type structure with relatively flat sidewalls. Alternatively, for example, such as... Figure 10 As shown, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 may include multiple substructures 18. The cross-sectional shape of the substructure 18 may be circular, elliptical, polygonal, or similar. Different substructures 18 may have the same or different cross-sectional shapes. In addition, different substructures 18 may be a complete integral structure, or at least a portion of the area of ​​two adjacent substructures 18 may be merged (i.e., the edge area of ​​at least one of two adjacent substructures 18 may be submerged into the other). This arrangement helps to conceal the smaller edge dimensions of two adjacent substructures 18 within the larger dimensions of each other, forming a better connection. This results in each region of the strip-shaped recess 16 and / or strip-shaped protrusion 17 having a larger width along its own extension direction, increasing the proportion of the strip-shaped recess 16 and / or strip-shaped protrusion 17 in the first region 15. This increases the specific surface area of ​​the first region 15, thereby increasing the leakage contact area between the first doped semiconductor layer 12 and the second doped semiconductor layer 13 in the docking region 14, and reducing the risk of hot spots on the back contact battery.

[0127] It should be noted that, viewed from the top of the first surface of the semiconductor substrate, whether the boundaries of adjacent substructures can be observed at the fusion point between two adjacent substructures in at least one strip-shaped recess and / or strip-shaped protrusion can be determined based on the protrusion height or recess depth corresponding to these two adjacent substructures, and the actual application scenario. For example: Figure 10 As shown, in at least one strip-shaped recess 16 and / or strip-shaped protrusion 17, the boundary between two adjacent substructures can be roughly observed at the point where they merge. Or, as Figure 20As shown, if two adjacent substructures have roughly the same protrusion height or indentation depth, the boundary between them may not be displayed at the point where they merge. Alternatively, if two adjacent substructures have a difference in protrusion height or indentation depth, the boundary corresponding to the smaller protrusion height or larger indentation depth may be displayed at the point where they merge.

[0128] For example, the strip-shaped recesses and / or strip-shaped protrusions may include multiple tower-like structures arranged along the extending direction. This arrangement, compared to a textured surface structure, results in a relatively flat top or bottom surface of the tower-like structures, which is beneficial for improving the formation quality of the first and / or second doped semiconductor layers formed on the strip-shaped recesses and / or strip-shaped protrusions, and thus for improving the conversion efficiency of the back-contact battery.

[0129] Furthermore, within the same linear depression, the depths of different substructures can be the same or different. Similarly, within the same linear protrusion, the heights of different substructures can be the same or different.

[0130] For example, in the same strip-shaped recess, the distance between the bottoms of two adjacent substructures along the thickness direction of the semiconductor substrate can be less than 2 μm. For instance, the distance between the bottoms of two adjacent substructures along the thickness direction of the semiconductor substrate in the same strip-shaped recess can be 0, 0.1 μm, 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, or 1.9 μm, etc. With this configuration, the undulation of the bottoms of different substructures along the thickness direction of the semiconductor substrate is smaller, which is beneficial for improving the coverage of the first doped semiconductor layer and / or the second doped semiconductor layer within the strip-shaped recess, improving the formation quality of the first doped semiconductor layer and / or the second doped semiconductor layer within the strip-shaped recess, and increasing the yield of the back contact battery.

[0131] For example, in the same strip-shaped protrusion, the distance between the tops of two adjacent substructures along the thickness direction of the semiconductor substrate can be less than 2 μm. For instance, the distance between the tops of two adjacent substructures along the thickness direction of the semiconductor substrate in the same strip-shaped protrusion can be 0, 0.1 μm, 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, or 1.9 μm, etc. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect described above where the distance between the bottoms of two adjacent substructures along the thickness direction of the semiconductor substrate can be less than 2 μm, and will not be repeated here.

[0132] For example, the one-dimensional dimension of the top of at least one substructure can be greater than or equal to 3 μm and less than or equal to 35 μm. For instance, the one-dimensional dimension of the top of at least one substructure can be 3 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 20 μm, 25 μm, 30 μm, or 35 μm, etc.

[0133] The meaning of the top one-dimensional dimension of the substructure can be determined based on the shape of the substructure. For example, when the substructure is a tower-like structure recessed into the semiconductor substrate, the one-dimensional dimension of the substructure is the side length or diagonal length of the opening of the tower-like structure.

[0134] like Figure 10 As shown, in a single first region 15, the extension direction of the strip-shaped recess 16 and / or the strip-shaped protrusion 17 can be set according to actual needs, such that the strip-shaped recess 16 and / or the strip-shaped protrusion 17 can extend from one side of at least one first region 15 that is distributed opposite to each other in the width direction to the other side.

[0135] For example, in a single first region, the angle between the extending direction of the strip-shaped recess and / or the strip-shaped protrusion and the width direction of the first region can be less than 20°. This arrangement helps to shorten the transmission path of leakage current between two electrodes with opposite conductivity types, reduce transmission losses, and reduce the risk of hot spots on the back contact battery.

[0136] For example, such as Figure 10 As shown, the extending direction of at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 can have an angle of less than 20° with the second direction. This arrangement results in a smaller angle between the extending direction of at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 and the alternating distribution direction of the first collector electrode 24 and the second collector electrode 25. This helps to shorten the transmission path of leakage current between the first collector electrode 24 and the second collector electrode 25, reducing transmission loss and the risk of hot spots on the back contact battery. Furthermore, since the specific direction referred to by the second direction is fixed, if the angle between the extending directions of the strip-shaped recess 16 and / or strip-shaped protrusion 17 and the second direction is small, the extending directions of different strip-shaped recesses 16 and / or strip-shaped protrusions 17 are approximately the same, which can reduce the manufacturing difficulty of forming the strip-shaped recesses 16 and / or strip-shaped protrusions 17 on the first surface.

[0137] In addition, such as Figure 10 and Figure 11 As shown, in a single first region 15, only one strip-shaped recess 16 or strip-shaped protrusion 17 may be provided. Alternatively, as... Figures 14 to 16As shown, at least one first region 15 may also have at least two strip-shaped recesses 16 and / or strip-shaped protrusions 17 on its surface; in this case, the arrangement of different strip-shaped recesses 16 and / or strip-shaped protrusions 17 within the same first region 15 can be set according to actual needs.

[0138] For example, the number of strip-shaped recesses and / or strip-shaped protrusions provided on the surface of at least one first region is less than or equal to 10. This configuration can prevent excessive leakage current due to excessive distribution density of strip-shaped recesses and / or strip-shaped protrusions provided in a single first region, ensuring that the back contact battery has high conversion efficiency; at the same time, it prevents the surface of the first region from being too rough, improving the film quality and passivation effect of the first doped semiconductor layer and the second doped semiconductor layer formed on the first region.

[0139] For example, such as Figure 13 As shown, within the surface of the same first region 15, the extending direction of one strip-shaped recess 16 or strip-shaped protrusion 17 can have an angle of less than or equal to 20° with the extending direction of another adjacent strip-shaped recess 16 or strip-shaped protrusion 17. This arrangement results in a smaller angle between different strip-shaped recesses 16 and / or strip-shaped protrusions 17, ensuring that the leakage current flows through approximately the same path length via the portion of the mating region 14 above the different strip-shaped recesses 16 and / or strip-shaped protrusions 17. This helps reduce transmission losses and the risk of hot spots on the back contact battery.

[0140] Additionally, when at least one first region has a plurality of strip-shaped recesses and / or strip-shaped protrusions on its surface, such as Figure 14 As shown, within the same first region 15, only multiple strip-shaped recesses 16 can be provided. Or, as... Figure 15 As shown, multiple strip-shaped protrusions 17 can also be provided. Alternatively, as... Figure 16 As shown, it is also possible to simultaneously provide a strip-shaped recessed portion 16 and a strip-shaped protrusion 17.

[0141] When both strip-shaped recesses and strip-shaped protrusions are provided within the same first zone, the strip-shaped recesses and protrusions can be distributed irregularly within the same first zone; or, as... Figure 16 As shown, the strip-shaped recesses 16 and strip-shaped protrusions 17 can be alternately distributed along the length of the first region 15. This arrangement creates a significant height difference between the surfaces of the areas between the strip-shaped recesses 16 and the strip-shaped protrusions 17, which helps to increase the specific surface area of ​​the first region 15 at this location. This, in turn, increases the leakage contact area of ​​the first doped semiconductor layer 12 and the second doped semiconductor layer 13 in the docking region 14, thereby increasing the leakage current and reducing the risk of hot spots on the back contact battery.

[0142] In practical applications, when the first surface comprises multiple first regions, all first regions may have strip-shaped recesses and / or strip-shaped protrusions. Alternatively, only some first regions may have strip-shaped recesses and / or strip-shaped protrusions. The proportion of the first regions with strip-shaped recesses and / or strip-shaped protrusions among all first regions can be set according to the actual needs of the back contact battery, such as conversion efficiency and hot spot risk, in the actual application scenario.

[0143] For example, the first region having strip-shaped recesses and / or strip-shaped protrusions accounts for more than or equal to 10% and less than or equal to 100% of all first regions. The beneficial effect in this case can be understood by referring to the beneficial effect described above where the number of strip-shaped recesses and / or strip-shaped protrusions on the surface of at least one first region is less than or equal to 10. Furthermore, this also prevents the leakage contact area of ​​the first and second doped semiconductor layers in the docking region from increasing too little due to the small number of first regions having strip-shaped recesses and / or strip-shaped protrusions, thus reducing the risk of hot spots on the back contact battery.

[0144] In practical applications, such as Figure 16 As shown, in the first surface, the strip-shaped recess 16 and / or the strip-shaped protrusion 17 may be provided only within the first region 15. Alternatively, as Figure 10 and Figure 13As shown, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 located within at least one first region 15 can extend into at least a portion of the surface of the second region 19 and / or the third region 20 adjacent to the first region 15. With this configuration, as described above, when the back contact battery is blocked, leakage current needs to pass through the docking region 14 and be discharged through the main region of the first doped semiconductor layer 12 and the main region of the second doped semiconductor layer 13 adjacent to the docking region 14. In the first surface, when the strip-shaped recess 16 and / or strip-shaped protrusion 17 extending from the first region 15 are provided in at least a portion of the surface of the second region 19 located below the main region of the first doped semiconductor layer 12 and / or the third region 20 located below the main region of the second doped semiconductor layer 13, the coverage area of ​​the portion of the main region of the first doped semiconductor layer 12 and / or the main region of the second doped semiconductor layer 13 near the docking region 14 on the first surface can be increased. Secondly, when the portions of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 located on the sides of the strip-shaped recesses 16 and / or the strip-shaped protrusions 17 have a greater thickness, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 located within at least one first region 15 also extends into at least a portion of the surface of the second region 19 and / or the third region 20 adjacent to the first region 15. This further enhances the conductivity between the main region of the first doped semiconductor layer 12 and / or the main region of the second doped semiconductor layer 13 and the docking region 14, forming a strip-shaped fast channel for charge carriers, which facilitates leakage current transmission, further reduces the risk of hot spots in the back contact battery, and further improves the burn-out resistance of the back contact battery.

[0145] When at least one strip-shaped recess and / or strip-shaped protrusion located in at least one first region further extends into at least a portion of the surface of a second region and / or a third region adjacent to the first region, the extending direction of the portion of the strip-shaped recess and / or strip-shaped protrusion in the first region may be the same as (an angle of less than 20° between the extending directions can be considered the same) or different from the extending direction of the portion of the strip-shaped recess and / or strip-shaped protrusion in the second region and / or the third region.

[0146] Secondly, for example, such as Figure 10As shown, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 located in the first region 15, and the corresponding strip-shaped recess 16 and / or strip-shaped protrusion 17 in the second region 19 and / or third region 20 adjacent to the first region 15, can be collinear (collinearity is considered when the distance between the two extending directions along the length direction of the first region 15 is less than or equal to the width of a single strip-shaped recess or a single strip-shaped protrusion); or, they can be staggered by a certain distance (optionally, the staggered distance can be greater than the width of a single strip-shaped recess or a single strip-shaped protrusion, but less than or equal to three times the width of a single strip-shaped recess or a single strip-shaped protrusion). The width of a single strip-shaped recess or a single strip-shaped protrusion can be determined by the morphology of its constituent substructures and the arrangement of the substructures. For example... Figure 10 As shown, when at least one strip-shaped recess and / or strip-shaped protrusion comprises multiple base-like substructures, the width of a single strip-shaped recess or a single strip-shaped protrusion can be the diagonal length of the base-like substructure. Alternatively, the width of a single strip-shaped recess or a single strip-shaped protrusion can be obtained by averaging the widths at at least three locations within the single strip-shaped recess or a single strip-shaped protrusion.

[0147] It is worth noting that when the portions of the first and / or second doped semiconductor layers located on the sides of the strip-shaped recesses and / or protrusions have a greater thickness, these portions exhibit higher conductivity, and the corresponding leakage current preferentially propagates within these portions. Therefore, by aligning at least one strip-shaped recess and / or protrusion located in the first region, and corresponding strip-shaped recesses and / or protrusions in the adjacent second and / or third regions, the portions of the first and second doped semiconductor layers with lower propagation losses along the leakage current propagation path can be connected in series through these collinear strip-shaped recesses and / or protrusions. This facilitates leakage current passage while also shortening the leakage current propagation path and reducing the risk of hot spots on the back contact battery.

[0148] Furthermore, along the thickness direction of the semiconductor substrate, the surface of one of the second and third regions can have a height difference with the surface of the first region. This allows the strip-shaped recesses and / or strip-shaped protrusions disposed in the first region to break at the boundary between the second or third region, which has a surface height difference with itself. This helps control the leakage current at the boundary, improves the carrier recombination loss of the back contact battery in the forward voltage region, and increases the conversion efficiency of the back contact battery. Moreover, in this case, if... Figure 10As shown, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 located in the first region 15, and the corresponding strip-shaped recess 16 and / or strip-shaped protrusion 17 in the second region 19 and / or third region 20 adjacent to the first region 15 are collinear. This facilitates the leakage current to be transmitted to the electrode and discharged through the portion of the first doped semiconductor layer 12 and the second doped semiconductor layer 13 above the strip-shaped recess 16 and / or strip-shaped protrusion 17 after flowing through the first region 15 and the boundary between the second region 19 or the third region 20 which has a surface height difference with itself. This reduces transmission loss and can balance the conversion efficiency and hot spot risk of the back contact battery, thereby improving the working performance of the back contact battery.

[0149] like Figure 10 As shown, when there is a height difference between the surface of one of the second region 19 and the third region 20 and the surface of the first region 15, and the surface of the other region is at the same height as the surface of the first region 15, the one-dimensional dimension of the strip-shaped recess 16 and / or strip-shaped protrusion 17 located in at least one of the three regions with a larger height can be the same as or different from the one-dimensional dimension of the strip-shaped recess 16 and / or strip-shaped protrusion 17 located in at least one of the three regions with a smaller height. The difference in the one-dimensional dimension of the strip-shaped recess 16 and / or strip-shaped protrusion 17 within the surfaces of the three regions with a height difference can be set according to actual needs.

[0150] For example, such as Figure 10 As shown, the depth of the strip-shaped recess 16 located in at least one of the three regions 15, 19 and 20 with a greater height is greater than the depth of the strip-shaped recess 16 located in at least one of the three regions with a smaller height, or the height of the strip-shaped protrusion 17 located in at least one of the three regions 15, 19 and 20 with a greater height is less than the height of the strip-shaped protrusion 17 located in at least one of the three regions with a smaller height. This configuration helps to reduce the height difference between the bottom of the strip-shaped recess 16 in the second region 19 and the third region 20 where there is a height difference with the surface of the first region 15, and the bottom of the strip-shaped recess 16 in the surface of the first region 15; or it helps to reduce the height difference between the top of the strip-shaped protrusion 17 in the second region 19 and the third region 20 where there is a height difference with the surface of the first region 15, and the top of the strip-shaped protrusion 17 in the surface of the first region 15, thereby reducing the coverage length of the first doped semiconductor layer 12 or the second doped semiconductor layer 13 at the junction of the two regions with a height difference, which helps to shorten the transmission distance of leakage current at the junction, reduce transmission loss, and reduce the risk of hot spots on the back contact battery.

[0151] For example: Figure 10As shown, when the first region 15 is located within a portion of the second region 19, and the surfaces of the first region 15 and the second region 19 are higher than the surface height of the third region 20, the depth of the strip-shaped recess 16 located in the first region 15 and the second region 19 can be greater than the depth of the strip-shaped recess 16 located in the third region 20; or, the height of the strip-shaped protrusion 17 located in the first region 15 and the second region 19 is less than the height of the strip-shaped protrusion 17 located in the third region 20.

[0152] For example, such as Figure 10 As shown, the width of the strip-shaped recess 16 and / or strip-shaped protrusion 17 located in at least one of the three regions (first region 15, second region 19, and third region 20) with a smaller height is greater than the width of the strip-shaped recess 16 and / or strip-shaped protrusion 17 located in the three regions (first region 15, second region 19, and third region 20) with a larger height, is advantageous because after extending to the region boundary, the strip-shaped recess 16 and / or strip-shaped protrusion 17 located in the three regions (first region 15, second region 19, and third region 20) can connect with the strip-shaped recess 16 and / or strip-shaped protrusion 17 located in the three regions (second region 19 and third region 20) with a smaller height. This facilitates the transmission of leakage current in the docking region 14 located above the first region 15, and in the main regions of the first doped semiconductor layer 12 and the second doped semiconductor layer 13 located above the second region 19 and the third region 20, which have a surface height difference from the first region 15, thereby reducing transmission loss. Furthermore, the strip-shaped recesses 16 and / or strip-shaped protrusions 17 located in at least one of the shorter regions 15, 19, and 20 have a larger width, resulting in a larger specific surface area. This allows the first doped semiconductor layer 12 or the second doped semiconductor layer 13 located on the shorter region 15, 19, or 20 to have a larger leakage current transmission area. Conversely, the strip-shaped recesses 16 and / or protrusions 17 located in the shorter region have a smaller width, resulting in a smaller specific surface area. This allows the first doped semiconductor layer 12 or the second doped semiconductor layer 13 located on the shorter region to have a smaller leakage current transmission area. This facilitates the transmission of leakage current between the first doped semiconductor layer 12 and the second doped semiconductor layer 13 within the mating region 14 from above the relatively smaller specific surface area of ​​the first region 15 to above the larger specific surface area of ​​the second region 19 or the third region 20. The transmission loss along the leakage current transmission path gradually decreases, achieving relay conduction of leakage current and reducing the risk of hot spots on the back contact battery.

[0153] For example: Figure 10 As shown, when the first region 15 is located within a portion of the second region 19, and the surfaces of the first region 15 and the second region 19 are higher than the surface height of the third region 20, the width of the strip-shaped recess 16 and / or the strip-shaped protrusion 17 located in the third region 20 can be greater than the width of the strip-shaped recess 16 and / or the strip-shaped protrusion 17 located in the first region 15 and the second region 19.

[0154] Optionally, the first and second regions have the same surface height, and along the direction from the second surface to the first surface, the surface height of the third region is less than that of the first region. The width of the strip-shaped recesses and / or strip-shaped protrusions located in the third region is greater than the width of the strip-shaped recesses and / or strip-shaped protrusions located in the first region. A portion of the second doped semiconductor layer also extends from the third region to the trench region and covers a portion of the first doped semiconductor layer. With this configuration, it can be understood that, along the thickness direction away from the semiconductor substrate, the surface undulation of the first doped semiconductor layer near the second region and corresponding to the strip-shaped recess and / or strip-shaped protrusion is greater than the surface undulation of the side away from the second region and corresponding to the strip-shaped recess and / or strip-shaped protrusion. As a result, the surface undulation of the second doped semiconductor layer in the first region corresponding to the strip-shaped recess and / or strip-shaped protrusion is smaller. When the width of the strip-shaped recess and / or strip-shaped protrusion in the third region is larger, the undulation of the second doped semiconductor layer in the third region located at the strip-shaped recess and / or strip-shaped protrusion can be increased. That is, at least the leakage current transmission area of ​​the second doped semiconductor layer in the third region is increased, the transmission resistance is reduced, which is conducive to the relay conduction of leakage current and reduces the risk of hot spots on the back contact battery.

[0155] When multiple first regions are provided within the first surface, that is, multiple docking regions are formed through the first doped semiconductor layer and the second doped semiconductor layer, for example, such as Figure 17 As shown, along the width direction of the first region 15, at least one pair of opposing first regions 15 can be provided on both sides of at least one second region 19 or third region 20, and the strip-shaped recesses 16 and / or strip-shaped protrusions 17 located in the opposing first regions 15 extend and intersect in a direction of mutual approach. With this arrangement, the two opposing docking regions 14 can be connected in series through the main region of the first doped semiconductor layer 12 or the main region of the second doped semiconductor layer 13 located above the extended strip-shaped recesses 16 and / or strip-shaped protrusions 17. This not only helps to increase the leakage current, but also allows the leakage current at both docking regions 14 to be discharged through the main region of the first doped semiconductor layer 12 or the main region of the second doped semiconductor layer 13 located above the strip-shaped recesses 16 and / or strip-shaped protrusions 17, which helps to shorten the leakage current transmission path, reduce leakage current transmission loss, and reduce the risk of hot spots on the back contact battery.

[0156] Or, such as Figure 18 As shown, when multiple first regions 15 are provided on the same second region 19 or third region 20, different first regions 15 can also be staggered along the extension direction of the second region 19 or third region 20. This arrangement reduces the risk of short circuits caused by the mating region 14 contacting electrodes of opposite conductivity types, thereby improving the electrical reliability of the back contact battery.

[0157] When at least one strip-shaped recess and / or strip-shaped protrusion located in at least one first region further extends into at least a portion of the surface of a second region and / or a third region adjacent to the first region, the extension range of the strip-shaped recess and / or strip-shaped protrusion in the second region and / or the third region can be determined according to the requirements of hot spot risk and conversion efficiency of the back contact battery in the actual application scenario, and is not specifically limited here.

[0158] In some embodiments, along the thickness direction of the semiconductor substrate, the surfaces of the first region, the second region, and the third region have different heights relative to the second surface of the semiconductor substrate, with the height difference between the highest and lowest surfaces being H. The depth of the recessed portion and / or the height of the raised portion can be set to be less than or equal to H along the thickness direction of the semiconductor substrate. This setting helps to ensure good flatness of the semiconductor substrate, effectively guaranteeing the deposition of the first and second doped semiconductor layers, as well as the electrode fabrication effect, in addition to the function of preventing hot spots.

[0159] For example, such as Figure 17 and Figure 18 As shown, when the back contact battery also includes a first current collector 24 and a second current collector 25, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 extends from the first region 15 into the orthographic projection region of the first current collector 24 in the second region 19; and / or, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 extends from the first region 15 into the orthographic projection region of the second current collector 25 in the third region 20. This configuration, taking at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 extending from the first region 15 to the orthogonal projection area of ​​the first collector electrode 24 in the second region 19 as an example: In this case, the first doped semiconductor layer 12 above the strip-shaped recess 16 and / or strip-shaped protrusion 17 extending from the first region 15 to the orthogonal projection area of ​​the first collector electrode 24 in the second region 19 has a large coverage area on the strip-shaped recess 16 and / or strip-shaped protrusion 17. When the first doped semiconductor layer 12 has a larger thickness on the side of the strip-shaped recess 16 and / or strip-shaped protrusion 17, it can also enhance the conductivity of the portion of the first doped semiconductor layer 12 located on the leakage current transmission path between the docking region 14 and the first collector electrode 24, which helps to reduce its own leakage current transmission loss and reduce the risk of hot spots on the back contact battery.

[0160] Alternatively, at least one strip-shaped recess and / or strip-shaped protrusion may extend from the first region into the second region without touching the orthographic projection area of ​​the first collector electrode in the second region; and / or, at least one strip-shaped recess and / or strip-shaped protrusion may extend from the first region into the third region without touching the orthographic projection area of ​​the second collector electrode in the third region.

[0161] In addition, such as Figure 17 and Figure 18 As shown, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 can extend from the first region 15 into the orthographic projection region of the first current collector 24 in the second region 19, and continue to extend within the second region 19; and / or, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 can extend from the first region 15 into the orthographic projection region of the second current collector 25 in the third region 20, and continue to extend within the third region 20. In this case, the extension endpoint of the strip-shaped recess 16 and / or strip-shaped protrusion 17 within the second region 19 and / or the third region 20 can be set according to actual needs.

[0162] For example, such as Figure 17 and Figure 18 As shown, when the first surface also includes a trench region 22 located between the second region 19 and the third region 20, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 extending from the first region 15 into the second region 19 can terminate at the boundary between the second region 19 and the trench region 22; and / or, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 extending from the first region 15 into the third region 20 can terminate at the boundary between the third region 20 and the trench region 22. With this configuration, it is unnecessary to provide strip-shaped recesses 16 and / or strip-shaped protrusions 17 within the trench region 22 where leakage current is not transmitted, thus reducing the processing area required to form the strip-shaped recesses 16 and / or strip-shaped protrusions 17 and improving manufacturing efficiency. In addition, at least one strip-shaped recess 16 and / or strip-shaped protrusion 17 extending from the first region 15 to the second region 19 and / or the third region 20 stops extending only at the boundary of the trench region 22. This helps to ensure that the leakage current has low transmission loss at each part of the transmission path between the docking region 14 and the first collector electrode 24 and / or the second collector electrode 25, thereby reducing the risk of hot spots on the contact battery.

[0163] Alternatively, when the first surface also includes a grooved area located between the second and third areas, at least one strip-shaped recess and / or strip-shaped protrusion extending from the first area into the second area may terminate at the area between the second area and the grooved area; and / or, at least one strip-shaped recess and / or strip-shaped protrusion extending from the first area into the third area may terminate at the area between the third area and the grooved area.

[0164] Alternatively, if the first surface also includes a groove area located between the second and third areas, at least one strip-shaped recess and / or strip-shaped protrusion extending from the first area to the second area may continue to extend into the groove area; and / or, at least one strip-shaped recess and / or strip-shaped protrusion extending from the first area to the third area may continue to extend into the groove area.

[0165] Additionally, in the second and / or third zones, the surfaces of areas that do not intersect with the extending direction of the adjacent first zone may not have strip-shaped recesses and / or strip-shaped protrusions provided; or, as... Figure 19 As shown, in the second region 19 and / or the third region 20, the surface of the area that does not intersect with the extending direction of the adjacent first region 15 may also be provided with strip-shaped recesses 16 and / or strip-shaped protrusions 17. In this case, the number and distribution of the strip-shaped recesses 16 and / or strip-shaped protrusions 17 on the surface of this area can be set according to actual needs. Optionally, the strip-shaped recesses 16 and / or strip-shaped protrusions 17 on the surface of this area may be irregularly distributed, or, as... Figure 19 As shown, the extending directions of the strip-shaped recesses 16 and / or strip-shaped protrusions 17 on the surface of the regions within the second region 19 and / or the third region 20 that do not intersect with the extending direction of the adjacent first region 15 can also be parallel to the extending directions of the strip-shaped recesses 16 and / or strip-shaped protrusions 17 located within the first region 15. This arrangement helps to enhance the conductivity of the main region of the first doped semiconductor layer 12 and / or the portion of the main region of the second doped semiconductor layer 13 that does not intersect with the extending direction of the adjacent docking region 14, reducing transmission resistance. It also facilitates current transmission along the extending directions of the strip-shaped recesses 16 and / or strip-shaped protrusions 17 to the docking region 14, reducing transmission losses and mitigating the risk of hot spots on the back contact battery. Furthermore, it enhances the carrier collection capability of the main region of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13, thereby improving the conversion efficiency of the back contact battery in the forward voltage region.

[0166] Secondly, embodiments of this application provide a photovoltaic module including a cell string and an encapsulation layer. The cell string is formed by connecting multiple back-contact cells as provided in the first aspect and its various implementations. The encapsulation layer covers the surface of the cell string.

[0167] The beneficial effects of the second aspect and its various implementations in the embodiments of this application can be found by referring to the analysis of the beneficial effects of the first aspect and its various implementations, and will not be repeated here.

[0168] The above description does not provide detailed explanations of the technical aspects of each layer's patterning, etching, etc. However, those skilled in the art should understand that various technical means can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination.

[0169] The embodiments of this application have been described above. However, these embodiments are merely for clarity and are not intended to limit the scope of this application. The scope of this application is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this application, and all such substitutions and modifications should fall within the scope of this application.

Claims

1. A back-contact battery, characterized in that, include: Semiconductor substrate, first doped semiconductor layer, second doped semiconductor layer, first collector electrode and second collector electrode; The second doped semiconductor layer has the opposite conductivity type to the first doped semiconductor layer; The semiconductor substrate includes a first surface and a second surface opposite to each other; the first doped semiconductor layer and the second doped semiconductor layer are disposed on the first surface, and there is an isolation region between the main region of the first doped semiconductor layer and the main region of the second doped semiconductor layer; a portion of the first doped semiconductor layer and a portion of the second doped semiconductor layer are connected to form a docking region; The first collector electrode is disposed on the side of the first doped semiconductor layer opposite to the semiconductor substrate; The second collector electrode is disposed on the side of the second doped semiconductor layer opposite to the semiconductor substrate; Wherein, in the first surface of the semiconductor substrate, the region located below the docking area is a first region; at least one strip-shaped recess and / or strip-shaped protrusion is provided in the first surface of the semiconductor substrate; the strip-shaped recess and / or the strip-shaped protrusion extends from one side of at least one of the two sides of the first region that are distributed opposite each other in the width direction to the other side.

2. The back contact battery according to claim 1, characterized in that, Along the thickness direction of the semiconductor substrate, the thickness L1 of the portion of the first doped semiconductor layer and / or the second doped semiconductor layer located on the side of the strip-shaped recess and / or the strip-shaped protrusion is greater than the thickness L2 of the remaining portion of itself.

3. The back contact battery according to claim 2, characterized in that, The ratio of L2 to L1 is greater than or equal to 1.05 and less than 5; And / or, the difference between L2 and L1 is greater than or equal to 25nm and less than 800nm.

4. The back contact battery according to claim 1, characterized in that, At least one of the strip-shaped recesses and / or strip-shaped protrusions comprises multiple substructures; at least a portion of the regions of at least two adjacent substructures are merged.

5. The back contact battery according to claim 1, characterized in that, The width of at least one of the strip-shaped recesses and / or the strip-shaped protrusions is greater than or equal to 200 nm and less than or equal to 80 μm; And / or, at least one strip-shaped recess corresponds to a recess depth greater than or equal to 50 nm and less than or equal to 30 μm; And / or, at least one of the strip-shaped protrusions has a protrusion height greater than or equal to 50 nm and less than or equal to 30 μm.

6. The back contact battery according to claim 1, characterized in that, The number of the strip-shaped recesses and / or the strip-shaped protrusions provided on the surface of at least one of the first regions is less than or equal to 10; And / or, in the case where the first surface includes multiple first areas, the first area provided with the strip-shaped recess and / or the strip-shaped protrusion accounts for more than or equal to 10% and less than or equal to 100% of all the first areas.

7. The back contact battery according to any one of claims 1 to 6, characterized in that, In the first surface of the semiconductor substrate, the region corresponding to the main region of the first doped semiconductor layer is defined as the second region, and the region corresponding to the main region of the second doped semiconductor layer is defined as the third region. At least one of the strip-shaped recesses and / or strip-shaped protrusions located in at least one of the first regions also extend into at least a portion of the surface of the second region and / or the third region adjacent to the first region.

8. The back contact battery according to claim 7, characterized in that, At least one of the strip-shaped recesses and / or strip-shaped protrusions located in the first region are collinear with the corresponding strip-shaped recesses and / or strip-shaped protrusions in the second region and / or the third region adjacent to the first region.

9. The back contact battery according to claim 7, characterized in that, Along the width direction of the first region, at least one pair of oppositely distributed first regions are provided on both sides of at least one second region or the third region, and the strip-shaped recesses and / or strip-shaped protrusions located in the oppositely distributed first regions extend and intersect in a direction that approaches each other.

10. The back contact battery according to claim 7, characterized in that, At least one of the strip-shaped recesses and / or the strip-shaped protrusions further extend from the first region to the orthogonal projection region of the first current collector electrode in the second region; and / or, at least one of the strip-shaped recesses and / or the strip-shaped protrusions further extend from the first region to the orthogonal projection region of the second current collector electrode in the third region.

11. The back contact battery according to claim 10, characterized in that, The first surface further includes a trench region located between the second region and the third region; the trench region is used to physically insulate a portion of the first doped semiconductor layer and a portion of the second doped semiconductor layer. At least one of the strip-shaped recesses and / or strip-shaped protrusions extending from the first region into the second region terminates at the boundary between the second region and the groove region; and / or, at least one of the strip-shaped recesses and / or strip-shaped protrusions extending from the first region into the third region terminates at the boundary between the third region and the groove region.

12. The back contact battery according to claim 7, characterized in that, In the second region and / or the third region, the surface of the area that does not intersect with the extending direction of the adjacent first region is provided with the strip-shaped recess and / or the strip-shaped protrusion, and the extending direction of the strip-shaped recess and / or the strip-shaped protrusion in the surface of the area that does not intersect with the extending direction of the adjacent first region in the second region and / or the third region is parallel to the extending direction of the strip-shaped recess and / or the strip-shaped protrusion in the first region.

13. The back contact battery according to claim 7, characterized in that, The surface of one of the second and third regions has a height difference from the surface of the first region, and the surface of the other region has the same height as the surface of the first region; Wherein, the depth of the strip-shaped recess located in at least one of the three regions with a greater height is greater than the depth of the strip-shaped recess located in at least one of the three regions with a smaller height, or the height of the strip-shaped protrusion located in at least one of the three regions with a greater height is less than the height of the strip-shaped protrusion located in at least one of the three regions with a smaller height. And / or, the width of the strip-shaped recess and / or the strip-shaped protrusion located in at least one of the first, second, and third regions with a smaller height is greater than the width of the strip-shaped recess and / or the strip-shaped protrusion located in at least one of the regions with a larger height.

14. The back contact battery according to claim 11, characterized in that, The first region and the second region have the same surface height, and along the direction from the second surface to the first surface, the surface height of the third region is less than the surface height of the first region; The width of the strip-shaped recess and / or the strip-shaped protrusion located in the third region is greater than the width of the strip-shaped recess and / or the strip-shaped protrusion located in the first region; A portion of the second doped semiconductor layer extends from the third region to the trench region and covers a portion of the first doped semiconductor layer.

15. The back contact battery according to claim 1, characterized in that, The plurality of first collector electrodes and the plurality of second collector electrodes extend along a first direction and are alternately distributed along a second direction; the first direction and the second direction are perpendicular to each other; The angle between the extending direction of at least one of the strip-shaped recesses and / or the strip-shaped protrusions and the second direction is less than 20°.

16. The back contact battery according to claim 1, characterized in that, At least one of the surfaces of the first region is provided with at least two of the strip-shaped recesses and / or the strip-shaped protrusions; Wherein, within the surface of the same first region, the angle between the extending direction of one of the strip-shaped recesses or strip-shaped protrusions and the extending direction of another strip-shaped recess or strip-shaped protrusion adjacent to itself is less than or equal to 20°. And / or, the strip-shaped recess and the strip-shaped protrusion are simultaneously provided on the surface of the same first region, and the strip-shaped recess and the strip-shaped protrusion are alternately distributed along the length direction of the first region.

17. The back contact battery according to claim 1, characterized in that, The length of at least one of the docking regions is greater than or equal to 20 μm and less than or equal to 1000 μm; And / or, at least one of the isolation zones has a width greater than or equal to 20 μm and less than or equal to 1000 μm; And / or, the length of at least one of the mating areas is greater than the distance between two adjacent strip-shaped recesses and / or strip-shaped protrusions.

18. A photovoltaic module, characterized in that, include: A battery string, wherein the battery string is formed by connecting a plurality of back-contact batteries as described in any one of claims 1 to 17; And an encapsulation layer that covers the surface of the battery string.

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