A back-contact battery and photovoltaic module

Abstract

This invention discloses a back-contact battery and a photovoltaic module, relating to the field of photovoltaic technology, for reducing the leakage risk between a first doped semiconductor layer and a second doped semiconductor layer. The back-contact battery includes: a semiconductor substrate, a first doped semiconductor layer, and a second doped semiconductor layer. Along the direction from the first surface to the second surface, the surface of the spacer region is recessed inward relative to the surface of the first region to form a groove structure. The first doped semiconductor layer is at least partially disposed on the first region. The second doped semiconductor layer is disposed on the second region. The second doped semiconductor layer and the first doped semiconductor layer have opposite conductivity types. Wherein, along the extension direction of the spacer region, the first doped semiconductor layer includes a first boundary adjacent to the spacer region. Along the width direction of the spacer region, the first boundary includes a first sub-boundary located within the first region and a second sub-boundary extending from the first region to above the groove structure and located above the groove structure.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and more particularly to a back-contact battery and a photovoltaic module. Background Technology

[0002] 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.

[0003] However, in existing back-contact batteries, there is an isolation structure between the first and second doped semiconductor layers with opposite conductivity types on the back side. The actual efficiency of the battery is affected by the specific isolation structure, and the efficiency of current batteries still needs to be improved. Summary of the Invention

[0004] The purpose of this invention is to provide a back-contact battery and a photovoltaic module for improving the efficiency of the back-contact battery.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a back contact battery, comprising: a semiconductor substrate, a first doped semiconductor layer, and a second doped semiconductor layer. The semiconductor substrate includes a first surface and a second surface opposite to each other. The first surface includes alternating first and second regions, and a gap region located between the first and second regions. Along the direction from the first surface to the second surface, the surface of the gap region is recessed inward relative to the surface of the first region to form a groove structure. The first doped semiconductor layer is at least partially disposed on the first region. The second doped semiconductor layer is disposed on the second region. The second doped semiconductor layer and the first doped semiconductor layer have opposite conductivity types. Wherein, along the extension direction of the gap region, the first doped semiconductor layer includes a first boundary adjacent to the gap region. Along the width direction of the gap region, the first boundary includes a first sub-boundary located within the first region, and a second sub-boundary extending from the first region above the groove structure and located above the groove structure.

[0006] With the above technical solution, when the back contact battery is in operation, the first doped semiconductor layer and the second doped semiconductor layer can effectively shunt and collect charge carriers, which is beneficial for forming photocurrent. Secondly, the gap region between the first and second regions separates the first and second doped semiconductor layers, reducing the risk of leakage between them. Furthermore, along the width of the gap region, the first boundary of the first doped semiconductor layer not only includes a second sub-boundary extending from the first region to above the groove structure, but also has a portion of the first doped semiconductor layer corresponding to the second sub-boundary suspended above the groove structure. This facilitates the reflection of some light emitted from the first surface of the semiconductor substrate back to the semiconductor substrate and reused by the semiconductor substrate, improving the light utilization rate of the back contact battery. Additionally, the first boundary of the first doped semiconductor layer also includes a first sub-boundary located within the first region and away from the groove structure. In this case, the portion of the first doped semiconductor layer corresponding to the first sub-boundary is recessed within the first region relative to the first sidewall of the groove structure (the sidewall of the groove structure closest to the first region), increasing the distance between the first and second doped semiconductor layers and reducing the risk of leakage between them. Compared to existing back-contact batteries where each part of the first boundary is suspended above the groove structure, the back-contact battery provided by this invention has a lower risk of leakage and a lower carrier recombination rate. Furthermore, compared to batteries where each part of the first boundary is recessed into the first region, the back-contact battery provided by this invention has higher light utilization and can improve the working performance of the back-contact battery.

[0007] As one possible implementation, along the extension direction of the interval region, the total length of the first sub-boundary within the first region per unit length is greater than the total length of the second sub-boundary above the groove structure.

[0008] With the above technical solution, it is understood that the distance between the portion of the first doped semiconductor layer corresponding to the second sub-boundary and the second doped semiconductor layer is greater than that between the portion of the first doped semiconductor layer corresponding to the second sub-boundary. Therefore, when the total length of the first sub-boundary within the first region is greater than the total length of the second sub-boundary above the groove structure, the portion of the first boundary of the first doped semiconductor layer with a larger distance from the second doped semiconductor layer accounts for a higher proportion. This is beneficial for further reducing the leakage risk between the first and second doped semiconductor layers and reducing the carrier recombination rate of the back contact battery.

[0009] As one possible implementation, the first boundary of the first doped semiconductor layer near the spacer region has an alternating concave-convex structure, which includes concave boundaries and convex boundaries.

[0010] As one possible implementation, the first sub-boundary includes at least a partially concave boundary, and the second sub-boundary includes at least a partially convex boundary. In this case, the first sub-boundary of the first doped semiconductor layer disposed in the first region is opposite to at least a partially concave boundary in the alternating concave-convex structure, and the second sub-boundary of the first doped semiconductor layer disposed above the groove structure is opposite to at least a partially convex boundary in the alternating concave-convex structure. This is beneficial for better matching the fluctuation changes of the alternating concave-convex structure presented by the first boundary with the portion of the first doped semiconductor layer that is recessed into the first region and the portion of the first doped semiconductor layer that is suspended above the groove structure. This can reduce the increase in etching amount of the semiconductor substrate required to make the first boundary of the first doped semiconductor layer simultaneously have a first sub-boundary and a second sub-boundary, which is beneficial for increasing the light absorption area of ​​the semiconductor substrate and improving the conversion efficiency of the back contact cell.

[0011] As one possible implementation, the first sub-boundary includes at least a partially concave boundary and at least a partially convex boundary; or, the second sub-boundary includes at least a partially concave boundary and at least a partially convex boundary. This helps to reduce the manufacturing difficulty of back contact batteries and improve their yield.

[0012] As one possible implementation, along the extension direction of the interval region, the total length of adjacent convex and concave boundaries in the alternating concave-convex structure can be greater than or equal to 0.05 μm and less than or equal to 10 μm. In this case, the total length of adjacent convex and concave boundaries in the alternating concave-convex structure has a large selectable range, which is beneficial to improving the applicability of the back contact battery provided by the present invention in different application scenarios.

[0013] As one possible implementation, the distance W1 between adjacent concave boundaries or adjacent convex boundaries is greater than or equal to 1 μm and less than or equal to 15 μm. In this case, the total length of adjacent convex and concave boundaries in the alternating concave-convex structure has a large selectable range, which is beneficial to improving the applicability of the back contact battery provided by the present invention in different application scenarios.

[0014] As one possible implementation, along the width direction of the interval region, the extension width W2 of the first sub-boundary within the first region is less than or equal to 8 μm.

[0015] When the above technical solution is adopted, the extension width W2 of the first sub-boundary in the first region is within the above range, which helps to prevent the area ratio of the first doped semiconductor layer in the first region from being too small due to the extension width W2 of the first sub-boundary in the first region being too large. This helps to make the first doped semiconductor layer have a higher field passivation effect and carrier collection capability, and further improve the working performance of the back contact battery.

[0016] As one possible implementation, the extension width W3 of the second sub-boundary above the groove structure along the width direction of the interval region is less than or equal to 10 μm.

[0017] When the above technical solution is adopted, the extension width W3 of the second sub-boundary above the groove structure is within the above range, which helps to prevent the minimum spacing between the first doped semiconductor layer and the second doped semiconductor layer from being too small due to the extension width W3 of the second sub-boundary above the groove structure being too large, and further reduces the risk of leakage between the back contact batteries.

[0018] As one possible implementation, the groove structure has a first sidewall near the first region along the width direction of the spacing region. Along the width direction of the spacing region, the first region includes a first platform region near the first sidewall, the first platform region including a platform plane substantially perpendicular to the thickness direction of the semiconductor substrate.

[0019] When the above technical solution is adopted, the first platform region includes a platform surface that is approximately perpendicular to the thickness direction of the semiconductor substrate. In this case, the surface of the portion of the first region of the semiconductor substrate not directly covered by the first doped semiconductor layer (i.e., the first platform region) is relatively flat, which helps to reduce the number of surface defects in the first platform region and decrease the carrier recombination rate. Furthermore, the platform surface has high light reflectivity, which helps to reduce the probability of light emanating from the first platform region within the semiconductor substrate and improves the light utilization rate of the back contact battery.

[0020] As one possible implementation, the first platform area further includes a second sidewall that is away from the first sidewall and continuous with the platform surface. The second sidewall is disposed perpendicular to the platform surface, or the second sidewall is disposed inclined relative to the platform surface.

[0021] In the case of the above technical solution, the first platform region also includes a second sidewall that is continuous with the platform surface, indicating that along the direction from the first surface to the second surface, the platform surface is recessed into the semiconductor substrate relative to the surface of the region in the first region that is directly covered by the first doped semiconductor layer. This can reduce the height variation between the bottom surface of the groove structure and the surface of the region with a larger height in the first region, which is beneficial to the formation quality and coverage of the surface passivation layer at the junction of the first region and the spacer region, and reduces the carrier recombination rate at the junction of the first region and the spacer region.

[0022] As one possible implementation, a portion of the sidewalls of the first doped semiconductor layer are aligned with the second sidewalls of at least one adjacent first platform region; or, at least one first sub-boundary within the first region extends above the platform surface.

[0023] When the above technical solution is adopted, when a portion of the sidewall of the first doped semiconductor layer is aligned with a second sidewall of at least one adjacent first platform region, the distance between this portion of the sidewall of the first doped semiconductor layer and the second doped semiconductor layer is relatively large, which helps to further reduce the leakage risk between them. When at least one first sub-boundary located in the first region extends above the platform surface, although the distance between this portion of the first boundary and the second doped semiconductor layer is relatively small, the portion of the first doped semiconductor layer corresponding to this portion of the first boundary can reflect some of the light emitted from the platform surface, allowing some light to re-enter the semiconductor substrate, further improving the light utilization rate of the back contact battery.

[0024] As one possible implementation, the angle between the second sidewall and the platform surface is greater than or equal to 30° and less than or equal to 150°. In this case, when the angle between the second sidewall and the platform surface is within the above range, the size of the angle is relatively large, which can reduce the process difficulty of forming the first platform area.

[0025] As one possible implementation, along the extension direction of the interval region, the area ratio between the platform surfaces of two adjacent first platform regions is greater than or equal to 1.05 and less than or equal to 50. In this case, the platform surfaces of different first platform regions can be the same or different, and relatively large differences between the different platform surfaces are allowed to reduce the manufacturing difficulty of the first platform regions.

[0026] As one possible implementation, the height of the second sidewall along the thickness direction of the semiconductor substrate is greater than or equal to 0.05 μm and less than or equal to 8 μm.

[0027] With the above technical solution, the height of the second sidewall is within the aforementioned range. This helps prevent a large height difference between the bottom surface of the groove structure and the surface of the higher region in the first area due to a small second sidewall height, thus further improving the passivation effect of the surface passivation layer at the junction of the first region and the spacer region. Furthermore, it prevents a large etching amount in the semiconductor substrate corresponding to the first platform region due to a large second sidewall height, resulting in a larger light absorption depth in the semiconductor substrate corresponding to the first platform region. This improves the light utilization rate of the semiconductor substrate and further enhances the conversion efficiency of the back contact cell.

[0028] As one possible implementation, the back contact battery also includes an island-shaped passivation structure disposed on the first platform region, the island-shaped passivation structure being distributed at intervals from the first doped semiconductor layer.

[0029] When the above technical solution is adopted, the island-shaped passivation structure has a passivation function, which can passivate the surface of the region where the island-shaped passivation structure is formed on the semiconductor substrate, reduce the number of defects on the surface of the region, and reduce the carrier recombination rate. In addition, the island-shaped passivation structure and the surface of the first platform region have a height difference, which allows the side surface and / or top surface of the island-shaped passivation structure to reflect the incident light on one side of the first side of the back contact battery, change the transmission path of the incident light (such as increasing the reflection path of the incident light), which is beneficial for more incident light to be refracted into the battery, improve the incident light absorption ratio, and improve the bifaciality of the back contact battery.

[0030] As one possible implementation, at least one island passivation structure includes a doped semiconductor passivation portion; and / or, at least one island passivation structure includes an interface passivation portion.

[0031] With the above technical solution, the island-shaped passivation structure can be formed by at least two types of passivation components that offer good performance and are compatible with battery manufacturing processes: doped semiconductor passivation components and interface passivation components. This not only ensures the island-shaped passivation structure has a good passivation effect but also improves the yield of the back contact battery. Furthermore, since the doped semiconductor passivation components and interface passivation components are also materials used in manufacturing the back contact battery, the island-shaped passivation structure can be manufactured simultaneously with the corresponding structure in the back contact battery, improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process.

[0032] As one possible implementation, the material and conductivity type of the doped semiconductor passivation portion are the same as those of one of the first doped semiconductor layer and the second doped semiconductor layer.

[0033] Using the above technical solution, taking the example where the material and conductivity type of the doped semiconductor passivation portion included in the island passivation structure are the same as those of the second doped semiconductor layer, the island passivation structure can be manufactured simultaneously with the second doped semiconductor layer, thereby improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process of the back contact battery.

[0034] As one possible implementation, the back contact battery further includes a first interface passivation layer disposed between the semiconductor substrate and the first doped semiconductor layer, and a second interface passivation layer disposed between the semiconductor substrate and the second doped semiconductor layer. The material of the interface passivation portion is the same as the material of the first interface passivation layer or the second interface passivation layer. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect described above, where the material and conductivity type of the doped semiconductor passivation portion are the same as the material and conductivity type of one of the first doped semiconductor layer and the second doped semiconductor layer, respectively, and will not be repeated here.

[0035] As one possible implementation, the first doped semiconductor layer is a P-type doped semiconductor layer; and / or, the first doped semiconductor layer is an emitter doped layer.

[0036] In a second aspect, the present invention provides a photovoltaic module comprising a back contact battery provided in the first aspect and various implementations thereof.

[0037] The beneficial effects of the second aspect and its various implementations in this invention 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

[0038] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0039] Figure 1 A longitudinal cross-sectional view of a first structure of a back-contact battery provided in an embodiment of the present invention;

[0040] Figure 2 A longitudinal cross-sectional view of a second structure of a back-contact battery provided in an embodiment of the present invention;

[0041] Figure 3 A partial SEM image of the back contact battery provided in an embodiment of the present invention at the first boundary of the first doped semiconductor layer near the first region (the direction of the bold arrow in the figure is the extension direction of the spacer region);

[0042] Figure 4 Parts (1), (2) and (3) in the figure are top view structural diagrams of the back contact battery in a partial interval area provided in the embodiment of the present invention (the dashed lines in the figure show the morphology of the first sidewall, and the direction of the bold arrows in the figure is the extension direction of the interval area);

[0043] Figure 5 A longitudinal cross-sectional view of a third structure of a back-contact battery provided in an embodiment of the present invention;

[0044] Figure 6 A longitudinal cross-sectional view of a fourth structure of a back-contact battery provided in an embodiment of the present invention;

[0045] Figure 7 A longitudinal cross-sectional view of the fifth structure of the back contact battery provided in an embodiment of the present invention;

[0046] Figure 8 This is a longitudinal cross-sectional schematic diagram of the sixth structure of the back contact battery provided in an embodiment of the present invention;

[0047] Figure 9A longitudinal cross-sectional view of the seventh structure of the back contact battery provided in an embodiment of the present invention;

[0048] Figure 10 A longitudinal cross-sectional view of the eighth structure of the back contact battery provided in an embodiment of the present invention;

[0049] Figure 11 This is a longitudinal cross-sectional schematic diagram of the ninth structure of the back contact battery provided in an embodiment of the present invention.

[0050] Figure 12 A longitudinal cross-sectional view of the tenth structure of the back contact battery provided in an embodiment of the present invention;

[0051] Figure 13 A longitudinal cross-sectional view of the eleventh structure of the back contact battery provided in an embodiment of the present invention;

[0052] Figure 14 This is a longitudinal cross-sectional view of the twelfth structure of the back contact battery provided in an embodiment of the present invention.

[0053] Reference numerals in the attached figures: 11 is a semiconductor substrate, 12 is a first doped semiconductor layer, 13 is a second doped semiconductor layer, 14 is a first region, 15 is a second region, 16 is a spacer region, 17 is a groove structure, 18 is a first sub-boundary, 19 is a second sub-boundary, 20 is a concave boundary, 21 is a convex boundary, 22 is a first sidewall, 23 is a third sidewall, 24 is a first platform region, 25 is a platform surface, 26 is a second sidewall, 27 is an island passivation structure, 28 is a first interface passivation layer, and 29 is a second interface passivation layer. Detailed Implementation

[0054] Hereinafter, embodiments of the present invention will 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 the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0055] The accompanying drawings illustrate various structural schematic diagrams according to embodiments of the present invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. 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.

[0056] In the context of this invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. Furthermore, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element. To make the technical problems, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0057] 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0058] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 invention according to the specific circumstances.

[0059] A solar cell is a device that converts sunlight into electrical energy. Specifically, when a solar cell is in operation, sunlight shines on the semiconductor pn junction, forming new electron-hole pairs. Under the influence of the built-in electric field of the pn junction, photogenerated holes flow to the p-region, and photogenerated electrons flow to the n-region. When the circuit is connected, an electric current is generated. Solar cells where both the positive and negative electrodes are located on the back side of the cell are called back-contact cells. Compared to double-sided contact solar cells, the front side of a back-contact cell has no metal electrodes to block the light, resulting in higher light utilization on the light-facing side. Therefore, back-contact cells have higher short-circuit current and photoelectric conversion efficiency, making them one of the current technological directions for achieving high-efficiency crystalline silicon solar cells.

[0060] Specifically, a back-contact battery typically includes a semiconductor substrate and alternating first-doped and second-doped semiconductor layers disposed on the same surface of the semiconductor substrate. The first and second-doped semiconductor layers have opposite conductivity types to achieve carrier shunting and collection. To reduce the risk of leakage between the first and second-doped semiconductor layers, a groove structure is often provided in the gap between them to ensure that no residue remains in the gap area after the first and second-doped semiconductor layers have been patterned.

[0061] However, in actual manufacturing, due to the presence of the mask structure and the etchant used to etch the groove structure, lateral etching also occurs during the etching of the semiconductor substrate. This results in the ends of the first doped semiconductor layer near the spacer region being suspended above the groove structure. Although this suspended end is beneficial for reflecting some of the light emitted from the first surface back to the semiconductor substrate, because the suspended end is far from the substrate, it cannot directly and effectively collect the photogenerated carriers generated by the substrate. Instead, it acts as a transmission loss, affecting the fill factor. At the same time, the suspended end results in a smaller distance between the first and second doped semiconductor layers, thereby increasing the risk of leakage between the first and second doped semiconductor layers, which have opposite conductivity types.

[0062] To address the aforementioned technical problems, in a first aspect, embodiments of the present invention provide a back-contact battery. For example... Figures 1 to 4 As shown, the back contact battery includes: a semiconductor substrate 11, a first doped semiconductor layer 12, and a second doped semiconductor layer 13. The semiconductor substrate 11 includes a first surface and a second surface opposite to each other. The first surface includes an alternately spaced first region 14 and a second region 15, and a spacer region 16 located between the first region 14 and the second region 15. Along the direction from the first surface to the second surface, the surface of the spacer region 16 is recessed inward relative to the surface of the first region 14 to form a groove structure 17. The first doped semiconductor layer 12 is at least partially disposed on the first region 14. The second doped semiconductor layer 13 is disposed on the second region 15. The second doped semiconductor layer 13 and the first doped semiconductor layer 12 have opposite conductivity types. Wherein, along the extension direction of the spacer region 16, the first doped semiconductor layer 12 includes a first boundary adjacent to the spacer region 16. Along the width direction of the spacer region 16, the first boundary includes a first sub-boundary 18 located within the first region 14, and a second sub-boundary 19 extending from the first region 14 to above the groove structure 17 and located above the groove structure 17.

[0063] When the above technical solution is adopted, with the back contact battery in operation, the first and second doped semiconductor layers can effectively shunt and collect charge carriers, which is beneficial for the formation of photocurrent. Secondly, as... Figures 1 to 4 ,as well as Figure 8 As shown, the spacer region 16 disposed between the first region 14 and the second region 15 can separate the first doped semiconductor layer 12 and the second doped semiconductor layer 13, reducing the risk of leakage between them. Furthermore, along the width direction of the spacer region 16, the first boundary of the first doped semiconductor layer 12 not only includes a second sub-boundary 19 extending from the first region 14 to above the groove structure 17, but also has a portion of the first doped semiconductor layer 12 corresponding to the second sub-boundary 19 suspended above the groove structure 17. This facilitates the reflection of some light emitted from the first surface of the semiconductor substrate 11 back to the semiconductor substrate 11 for reuse, improving the light utilization rate of the back contact battery. Furthermore, the first boundary of the first doped semiconductor layer 12 also includes a first sub-boundary 18 located within the first region 14 and far from the groove structure 17. In this case, the portion of the first doped semiconductor layer 12 corresponding to the first sub-boundary 18 is recessed into the first region 14 relative to the first sidewall 22 of the groove structure 17 (the sidewall of the groove structure 17 near the first region 14; additionally, the groove structure 17 also has a third sidewall 23 near the second region 15. The boundaries of the first sidewall 22 and / or the third sidewall 23 can be straight, curved, or polygonal, etc., and their specific morphology can be determined according to the actual manufacturing process; no specific limitation is made here). This increases the distance between the first doped semiconductor layer 12 and the second doped semiconductor layer 13, reduces the leakage risk between them, and improves the fill factor of the solar cell. Compared with the prior art where each part of the first boundary is suspended above the groove structure 17, the back contact cell provided in this embodiment of the invention has a lower leakage risk, a lower carrier recombination rate, and a higher fill factor. Compared to the first boundary where each part is recessed into the first region 14, the back contact battery provided in this embodiment of the invention has a higher light utilization rate and can improve the working performance of the back contact battery.

[0064] In practical applications, the embodiments of the present invention do 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 any semiconductor material such as a germanium-silicon substrate, a germanium substrate, or a gallium arsenide substrate. Furthermore, the semiconductor substrate can be an N-type semiconductor substrate, a P-type semiconductor substrate, or an intrinsic semiconductor substrate.

[0065] Secondly, the semiconductor substrate includes a first surface and a second surface opposite to each other. 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. The distribution of the first region, the second region, and the spacer region on the first surface can be determined based on the distribution of the first doped semiconductor layer and the second doped semiconductor layer formed on the first surface. Specifically, since the first doped semiconductor layer of the back contact battery is at least partially disposed on the first region, the distribution range of the first region on the first surface can be determined based on the distribution requirements of the first doped semiconductor layer in the actual application scenario, as well as the leakage prevention requirements between the first and second doped semiconductor layers. Since the second doped semiconductor layer of the back contact battery is disposed on the second region of the first surface, the distribution range of the second region on the first surface can be determined based on the distribution requirements of the second doped semiconductor layer on the semiconductor substrate in the actual application scenario. As for the spacer region, after the distribution ranges of the first and second regions are determined, the distribution range of the spacer region on the first surface can be determined.

[0066] It is understandable that one of the first and second regions roughly corresponds to the emitter region, and the other roughly corresponds to the back field region. In terms of specific conductivity type, one of the first and second regions roughly corresponds to the P-region, and the other roughly corresponds to the N-region.

[0067] The shapes of the first and second regions can be set according to actual needs, as long as they can be applied to the back contact battery provided in the embodiments of the present invention. For example, the first and second regions can be arranged in alternating stripes or in alternating interdigitated shapes.

[0068] From the perspective of surface morphology, such as Figure 1 and Figure 2 As shown, the second surface of the semiconductor substrate 11 can be a polished surface. Or, as... Figure 5 As shown, the second surface of the semiconductor substrate 11 can also be textured to improve the light trapping effect of the second surface and improve the utilization rate of light by the semiconductor substrate 11.

[0069] As for the morphology of the first surface of the semiconductor substrate, the first surface can be a plane, which is beneficial to improve the formation quality of the first doped semiconductor layer and the second doped semiconductor layer on the first surface and improve their field passivation effect.

[0070] Or, such as Figure 5 As shown, the surface of the spacer region 16 included in the first side can be textured to improve the light trapping effect of the spacer region 16 and increase the bifaciality of the back contact battery.

[0071] In terms of surface height, the surface of the spacer region is recessed into the semiconductor substrate relative to the surface of the first region. The depth of the groove structure within the spacer region can be set according to actual needs and is not specifically limited here.

[0072] As for the surface of the second region, it can be flush with the surface of the first region; or, as... Figure 6 As shown, along the direction from the first surface to the second surface, the surface of the second region 15 can also be recessed into the semiconductor substrate 11 relative to the surface of the first region 14 to prevent residues remaining on the second region 15 after the patterned first doped semiconductor layer 12, thus reducing the risk of leakage. In this case, the surface of the second region can be flush with the surface of the spacer region; or, as shown... Figure 6 As shown, the surface of the second region 15 can also be higher than the bottom surface of the trench in the spacer region 16. As for the depth to which the surface of the second region 15 is recessed into the semiconductor substrate 11, it can be set according to actual needs, and no specific limitation is made here.

[0073] Regarding the first and second doped semiconductor layers, the embodiments of the present invention do not specifically limit the conductivity types of the first and second doped semiconductor layers, as long as the conductivity types of the first and second doped semiconductor layers are opposite. Specifically, the conductivity type of the first doped semiconductor layer can be N-type, and the conductivity type of the second doped semiconductor layer can be P-type. Alternatively, the conductivity type of the first doped semiconductor layer can also be P-type, and the conductivity type of the second doped semiconductor layer can be N-type.

[0074] Optionally, the first doped semiconductor layer is a P-type doped semiconductor layer; and / or, the first doped semiconductor layer is an emitter doped layer. In this case, a film layer with strong corrosion resistance, such as a borosilicate glass layer, can be used to protect the first doped semiconductor layer during the patterning process, which helps to ensure that the first boundary of the first doped semiconductor layer simultaneously has the aforementioned first sub-boundary and second sub-boundary, reducing the difficulty of the manufacturing process.

[0075] In terms of materials, the first doped semiconductor layer and / or the second doped semiconductor layer 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 doped semiconductor layer and / or the second doped semiconductor layer can be amorphous, microcrystalline, nanocrystalline, single crystal, or polycrystalline.

[0076] The materials of the first doped semiconductor layer and the second doped semiconductor layer can be the same or different. For example, the materials of the first doped semiconductor layer and the second doped semiconductor layer can both be doped polycrystalline silicon or doped amorphous silicon. Another example is that one of the first doped semiconductor layer and the second doped semiconductor layer is made of doped polycrystalline silicon, and the other is made of doped amorphous silicon.

[0077] In terms of formation location, such as Figure 6 As shown, at least a portion of the first doped semiconductor layer 12 can be directly disposed on the first region 14. Alternatively, as... Figure 7 As shown, the back contact battery may further include a first interface passivation layer 28 located between the first doped semiconductor layer 12 and the semiconductor substrate 11. In this case, the passivated contact structure composed of the first interface passivation layer 28 and the first doped semiconductor layer 12 has excellent interface passivation effect and can achieve selective collection of charge carriers, reduce the carrier recombination rate of the first region 14 on the first surface of the semiconductor substrate 11, and further improve the photoelectric conversion efficiency of the back contact battery. The material and thickness of the first interface passivation layer 28 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. As 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 layers.

[0078] As for the second doped semiconductor layer, it can be directly disposed on the second region. Or, as... Figure 7 As shown, the back contact cell may further include a second interface passivation layer 29 located between the second doped semiconductor layer 13 and the semiconductor substrate 11. In this case, the passivated contact structure composed of the second interface passivation layer 29 and the second doped semiconductor layer 13 has excellent interface passivation effect and can achieve selective collection of charge carriers, reduce the carrier recombination rate in the second region 15 of the first surface of the semiconductor substrate 11, and further improve the photoelectric conversion efficiency of the back contact cell. The principle for setting the material and thickness of the second interface passivation layer 29 can refer to the principle for setting the material and thickness of the first interface passivation layer 28 described above, and will not be repeated here.

[0079] In terms of edge morphology, such as Figures 1 to 7As shown, along the width direction of the spacing region 16, the first boundary of the first doped semiconductor layer 12 includes a first sub-boundary 18 located within the first region 14 and away from the groove structure 17, and a second sub-boundary 19 extending from the first region 14 to above the groove structure 17. As mentioned above, the portion of the first doped semiconductor layer 12 corresponding to the first sub-boundary 18 has a relatively large gap with the second doped semiconductor layer 13, which helps to reduce the leakage risk between them. The portion of the first doped semiconductor layer 12 corresponding to the second sub-boundary 19 is beneficial for reflecting some of the light emitted from the first surface of the semiconductor substrate 11 back to the semiconductor substrate 11 and being utilized by the semiconductor substrate 11 again, thereby improving the light utilization rate of the back contact battery. Therefore, the length ratio of the first sub-boundary 18 and the second sub-boundary 19 in the first boundary can be determined according to the requirements of leakage risk and light utilization rate of the back contact battery in the actual application scenario, and no specific limitation is made here.

[0080] For example, along the extension direction of the spacer region, within a unit length, for example, a unit length of 1 cm, the total length of the first sub-boundary within the first region can be greater than the total length of the second sub-boundary above the groove structure. The extension direction of the spacer region is perpendicular to the width direction of the spacer region. In this case, it can be understood that the distance between the portion of the first doped semiconductor layer corresponding to the first sub-boundary and the second doped semiconductor layer is larger than the portion of the first doped semiconductor layer corresponding to the second sub-boundary. Based on this, when the total length of the first sub-boundary within the first region is greater than the total length of the second sub-boundary above the groove structure within a unit length, the portion of the first boundary of the first doped semiconductor layer with a larger distance from the second doped semiconductor layer accounts for a higher proportion, which is beneficial to further reduce the leakage risk between the first and second doped semiconductor layers and reduce the carrier recombination rate of the back contact battery.

[0081] Alternatively, along the extension direction of the spacing region, the total length of the first sub-boundary within the first region within a unit length, such as 1 cm, can also be equal to the total length of the second sub-boundary above the groove structure. Or, there exists at least one 1 cm unit length where the total length of the first sub-boundary within the first region is less than the total length of the second sub-boundary above the groove structure. This reduces the manufacturing difficulty of the back contact battery without requiring the portion of the first doped semiconductor layer corresponding to the second sub-boundary to be smaller, thus reducing the area of ​​the first doped semiconductor layer within the first region. This is beneficial for the first doped semiconductor layer to have a higher field passivation effect and carrier collection capability.

[0082] In addition, in practical applications, such as Figure 3 and Figure 4As shown, the first boundary of the first doped semiconductor layer 12 near the spacer region 16 can have an alternating concave-convex structure, which includes a concave boundary 20 and a convex boundary 21. It should be understood that the concave boundary 20 and the convex boundary 21 do not completely correspond to the first sub-boundary and the second sub-boundary. In this embodiment of the invention, the correspondence between the concave boundary 20 and the convex boundary 21 of the alternating concave-convex structure and the first and second sub-boundaries is not specifically limited, but can be determined based on the positional relationship between the first sidewalls of the groove structure near the first region in the actual application scenario, as well as the leakage risk and light utilization requirements of the back contact battery.

[0083] Optionally, the first sub-boundary includes at least a portion of the concave boundary.

[0084] Optionally, the second sub-boundary includes at least a portion of the convex boundary.

[0085] Optionally, the first sub-boundary includes at least a partially concave boundary and at least a partially convex boundary;

[0086] Optionally, the second sub-boundary may also include at least a partially concave boundary and at least a partially convex boundary.

[0087] Optionally, when the first sub-boundary includes at least a partially concave boundary and the second sub-boundary includes at least a partially convex boundary, the first sub-boundary of the first doped semiconductor layer disposed in the first region is opposite to at least a partially concave boundary in the alternating concave-convex structure, and the second sub-boundary of the first doped semiconductor layer disposed above the groove structure is opposite to at least a partially convex boundary in the alternating concave-convex structure. This is beneficial to make the alternating concave-convex structure presented by the first boundary more matched with the fluctuation changes of the portion of the first doped semiconductor layer that is recessed into the first region and the portion of the first doped semiconductor layer that is suspended and disposed on the groove structure. This can reduce the increase in etching amount of the semiconductor substrate to make the first boundary of the first doped semiconductor layer simultaneously have the first sub-boundary and the second sub-boundary, which is beneficial to increase the light absorption area of ​​the semiconductor substrate and improve the conversion efficiency of the back contact cell.

[0088] For example, along the extension direction of the interval region, the total length of adjacent convex and concave boundaries in the alternating concave-convex structure can be greater than or equal to 0.05 μm and less than or equal to 10 μm. For instance, the total length of adjacent convex and concave boundaries in the alternating concave-convex structure can be 0.05 μm, 0.1 μm, 1 μm, 2 μm, 3 μm, 5 μm, 8 μm, or 10 μm, etc. In this case, the total length of adjacent convex and concave boundaries in the alternating concave-convex structure has a large selectable range, which is beneficial to improving the applicability of the back contact battery provided in the embodiments of the present invention in different application scenarios.

[0089] Along the overall extension direction of the first doped semiconductor layer, the distance W1 between adjacent concave boundaries or adjacent convex boundaries can be greater than or equal to 1 μm and less than or equal to 15 μm.

[0090] Optionally, along the width direction of the spacer region, the extension width W2 of the first sub-boundary within the first region is less than or equal to 8 μm. The extension width of the first sub-boundary within the first region can be understood as the maximum horizontal distance between the first sub-boundary and the first sidewall of the groove structure of the spacer region. In this case, the extension width of the first sub-boundary within the first region is within the above range, which helps to prevent the area ratio of the first doped semiconductor layer on the first region from being too small due to the extension width W2 of the first sub-boundary within the first region being too large, thereby reducing the effective area of ​​the junction region or field region.

[0091] Optionally, along the width direction of the spacing region, the extension width W3 of the second sub-boundary above the groove structure is less than or equal to 10 μm. The extension width of the second sub-boundary above the groove structure can be understood as the maximum horizontal distance between the second sub-boundary and the first sidewall of the groove structure. Within the above range, it is beneficial to prevent the fill factor from being affected by an excessively large extension width W3 of the second sub-boundary above the groove structure, and to prevent the minimum spacing between the first and second doped semiconductor layers from being too small, thus avoiding a large risk of leakage.

[0092] Optional, such as Figure 3 and Figure 4 As shown, along the width direction of the spacing region 16, the groove structure 17 has a first sidewall 22 near the first region 14. Along the width direction of the spacing region 16, the first region 14 may also include a first platform region 24 near the first sidewall 22. The first platform region 24 may include a platform surface 25 substantially perpendicular to the thickness direction of the semiconductor substrate 11. In this case, the first platform region 24 includes a platform surface 25 substantially perpendicular to the thickness direction of the semiconductor substrate 11. Optionally, the platform surface 25 of the first platform region 24 is relatively flat, for example, it can be a polished surface; the first doped semiconductor layer 12 is at least partially suspended above the platform surface 25. A flat surface helps reduce the number of defects on the platform surface and reduces the carrier recombination rate. Furthermore, the platform surface 25 has high light reflectivity, which helps reduce the probability of light emanating from the first platform region 24 within the semiconductor substrate 11, improving the light utilization rate of the back contact cell. It should be noted that if the angle between the platform surface 25 included in the first platform region 24 and the thickness direction of the semiconductor substrate 11 is greater than or equal to 85°, it can be considered that the platform surface 25 and the thickness direction of the semiconductor substrate 11 are approximately perpendicular.

[0093] Optionally, the platform surface of the first platform region is not perpendicular to the thickness direction of the semiconductor substrate. Optionally, the platform surface can also be an uneven surface with a pyramidal or perforated structure. The morphology of the surface included in the first platform region can be set according to actual needs and is not specifically limited here.

[0094] In terms of distribution location, such as Figures 9 to 11 As shown, at least a portion of the first doped semiconductor layer 12 is suspended above the first plateau region 24. Optionally, a first sub-boundary 18 is suspended above the first plateau region 24; alternatively, at least a portion of the second sub-boundary extends from above the first plateau region 24 to above the groove structure in a suspended manner.

[0095] Optional, such as Figures 9 to 14 As shown, the first platform region 24 may further include a second sidewall 26 that is away from the first sidewall 22 and continuous with the platform surface 25. The second sidewall 26 is disposed perpendicular to the platform surface 25, or the second sidewall 26 is disposed inclined relative to the platform surface 25. In this case, along the direction from the first surface to the second surface, the platform surface 25 is recessed into the semiconductor substrate 11 relative to the surface of the region in the first region 14 directly covered by the first doped semiconductor layer 12. This can reduce the height variation between the bottom surface of the groove structure 17 and the surface of the region with greater height in the first region 14, which is beneficial to the formation quality and coverage of the surface passivation layer at the junction of the first region 14 and the spacer region 16, reduces the carrier recombination rate at the junction of the first region 14 and the spacer region 16, and at the same time minimizes the transport path of photogenerated carriers on the inclined sidewall, while increasing the lateral transport path that is more conducive to carrier transport.

[0096] For example, the width of the first platform area is less than or equal to 10 μm.

[0097] Optionally, the angle between the second sidewall and the platform surface can be greater than or equal to 30° and less than or equal to 150°. For example, the angle between the second sidewall and the platform surface can be 30°, 40°, 50°, 60°, 80°, 100°, 120°, or 150°, etc. In this case, the range of the angle between the second sidewall and the platform surface is relatively large, which can reduce the process difficulty of forming the first platform area.

[0098] Regarding the height of the second sidewall, for example, along the thickness direction of the semiconductor substrate, the height of the second sidewall can be greater than or equal to 0.05 μm and less than or equal to 8 μm. For instance, the height of the second sidewall can be 0.05 μm, 0.1 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 7 μm, or 8 μm, etc. In this case, the height of the second sidewall being within the above range helps to prevent a large height difference between the bottom surface of the groove structure and the surface of the area with a larger height in the first region due to a small second sidewall height, which is beneficial to further improve the passivation effect of the surface passivation layer at the junction of the first region and the spacer region. Additionally, it can prevent a large etching amount in the portion of the semiconductor substrate corresponding to the first platform region due to a large second sidewall height, which is beneficial to having a larger light absorption depth in the portion of the semiconductor substrate corresponding to the first platform region, thereby improving the light utilization rate of the semiconductor substrate and further improving the conversion efficiency of the back contact cell.

[0099] Of course, depending on the size of the back contact battery and the requirements of different practical application scenarios, the height of the second sidewall can be set to any suitable value other than 0.05μm to 8μm; no specific limitation is made here. Furthermore, the heights of the second sidewalls in different first platform regions can be the same or different.

[0100] The size of the first plateau region can be determined based on the formation range of the first doped semiconductor layer in the first region, and is not specifically limited here. Specifically, different first plateau regions may have the same or different plateau surface areas.

[0101] Furthermore, in practical applications, besides the surface passivation layer, the first platform region of the back contact battery may not have any other structures formed. Or, in some cases, such as Figure 3 and Figure 4 As shown, the back contact battery may further include an island-shaped passivation structure 27 disposed on the first platform region 24. In this case, the island-shaped passivation structure 27 has a passivation function, which can passivate the surface of the region on the semiconductor substrate 11 where the island-shaped passivation structure 27 is formed, reduce the number of defects on the surface of the region, and reduce the carrier recombination rate. In addition, the island-shaped passivation structure 27 and the surface of the first platform region 24 may have a certain height difference, or the island-shaped passivation structure 27 and the semiconductor substrate 11 may have material differences, so that the side surface and / or top surface of the island-shaped passivation structure 27 can reflect or refract incident light on one side of the first surface of the back contact battery, change the transmission path of the incident light (such as increasing the reflection path of the incident light), which is beneficial for more incident light to be refracted into the battery, improve the incident light absorption ratio, and improve the bifaciality of the back contact battery. The island-shaped passivation structure 27 may be distributed at intervals with the first doped semiconductor layer 12, or at least a portion of the sidewall of the island-shaped passivation structure 27 may be adjacent to the first doped semiconductor layer 12.

[0102] From a morphological perspective, at least one island-shaped passivation structure may include multiple non-adjacent, clustered point-like passivation portions. In this case, it is beneficial to increase the specific surface area of ​​a single island-shaped passivation structure, enhance the light-trapping effect of the island-shaped passivation structure, and further improve the incident light absorption ratio and the bifaciality of the back-contact cell. In this case, the number of point-like passivation portions included in a single island-shaped passivation structure, as well as the distribution and morphology of different point-like passivation portions, can be set according to actual needs. The point-like passivation portions can be roughly regular hemispherical, circular / pyramidal, circular / frustum-shaped, circular / prism-shaped, or mountain-like shapes, or they can be irregular shapes with uneven surfaces.

[0103] Or, such as Figure 3 and Figure 4 As shown, at least one island-shaped passivation structure 27 can also be an integral structure with its different regions continuously distributed. This provides another example of the morphology of the island-shaped passivation structure 27, improving the applicability of the back contact battery provided in this embodiment of the invention in different application scenarios and reducing the manufacturing difficulty of the back contact battery. In this case, the island-shaped passivation structure 27 can have a relatively flat surface (at this time, the morphology of the island-shaped passivation structure 27 can refer to the morphology of the regularly shaped dot-shaped passivation portion described above); or, the surface of the island-shaped passivation structure 27 can also have an undulating morphology, and the direction, position, and size of the protrusion or concavity of the undulating morphology can be set according to actual needs and are not specifically limited here. The application principle of the beneficial effects when the different regions of at least one island-shaped passivation structure 27 are continuously distributed and the surface of the island-shaped passivation structure 27 has an undulating morphology can refer to the application principle of the beneficial effects of the island-shaped passivation structure 27 including multiple non-adjacent and clustered dot-shaped passivation portions described above.

[0104] Furthermore, the edge of at least one island-shaped passivation structure can have a generally regular shape. For example, when the island-shaped passivation structure is hemispherical, its edge is circular. Or, for example, when the island-shaped passivation structure is pyramidal, its edge is polygonal. Or, as... Figure 3 and Figure 4 As shown, at least one island-shaped passivation structure 27 has an irregularly shaped edge, which is beneficial for the island-shaped passivation structure 27 to have side surfaces arranged in different directions, thereby reflecting light incident from different directions. This facilitates the refraction of more incident light into the battery, further improving the incident light absorption ratio and the bifaciality of the back-contact battery. In this case, the specific morphology of the irregularly shaped edge of the island-shaped passivation structure 27 can be determined based on the three-dimensional morphology of the island-shaped passivation structure 27 described above, and is not specifically limited here.

[0105] It should be noted that when the island-like passivation structure comprises multiple non-adjacent, clustered passivation portions, the edge of the island-like passivation structure refers to the edge of the area occupied by the collective of these multiple non-adjacent, clustered passivation portions. When different regions of the island-like passivation structure are continuously distributed, the edge of the island-like passivation structure refers to the edge enclosed by the continuously distributed different regions.

[0106] In terms of size, the embodiments of the present invention do not specifically limit the size of the island passivation structure, but can determine it according to the passivation effect requirements of the island passivation structure and the light trapping requirements of the island passivation structure in the actual application scenario.

[0107] For example, the area occupied by at least one island-shaped passivation structure can be greater than or equal to 1 μm. 2 and less than or equal to 100μm 2 For example, the area occupied by at least one island-like passivation structure can be greater than or equal to 1 μm. 2 10μm 2 20μm 2 30μm 2 50μm 2 80μm 2 or 100μm 2 Etc. At least one island-shaped passivation structure occupies an area within the aforementioned range. This helps prevent the passivation effect of the island-shaped passivation structure from being too small, and also prevents the light-trapping effect improved by the island-shaped passivation structure itself or by the presence of the island-shaped passivation structure from being too low. This is beneficial for the back contact battery to have a higher bifaciality. In addition, it can also prevent the island-shaped passivation structure from occupying an area that is too large (the beneficial effects of preventing the island-shaped passivation structure from occupying an area that is too large can be referred to the previous text, and will not be repeated here).

[0108] For example, the longest side dimension of at least one island-shaped passivation structure can be greater than or equal to 0.5 μm and less than or equal to 9 μm. For instance, the longest side dimension of at least one island-shaped passivation structure can be 0.5 μm, 1 μm, 2 μm, 3 μm, 5 μm, 6 μm, 8 μm, or 9 μm, etc.

[0109] For example, the shortest side dimension of at least one island-shaped passivation structure can be less than or equal to 0.05 μm and less than or equal to 7.5 μm. For instance, the shortest side dimension of at least one island-shaped passivation structure can be 0.05 μm, 0.1 μm, 1 μm, 2 μm, 3 μm, 5 μm, 6 μm, 6.5 μm, 7 μm, or 7.5 μm, etc.

[0110] It should be noted that when the island-like passivation structure comprises multiple non-adjacent, clustered passivation portions, the area occupied by the island-like passivation structure refers to the area occupied by the entire group of non-adjacent, clustered passivation portions. When different regions of the island-like passivation structure are continuously distributed, the area occupied by the island-like passivation structure refers to the area enclosed by the continuously distributed different regions.

[0111] Structurally, the island-shaped passivation structure can be a single-layer structure or a stacked structure composed of different layers. The material used for the island-shaped passivation structure can be any material with passivation properties, as long as it can be applied to the back contact battery provided in the embodiments of this invention.

[0112] For example, at least one island-shaped passivation structure may include a doped semiconductor passivation portion; and / or, at least one island-shaped passivation structure may include an interface passivation portion. In this case, the island-shaped passivation structure can be formed by at least two passivation portions that are effective and compatible with battery manufacturing processes: a doped semiconductor passivation portion and an interface passivation portion. This not only provides good passivation effect for the island-shaped passivation structure but also improves the yield of the back contact battery. Furthermore, since the doped semiconductor passivation portion and the interface passivation portion are also materials used to manufacture the back contact battery, the island-shaped passivation structure can be manufactured simultaneously with the corresponding structure in the back contact battery, improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process.

[0113] It should be noted that the island passivation structure may include only the doped semiconductor passivation portion, or only the interface passivation portion, or it may be an island passivation structure that includes both the interface passivation portion and the doped semiconductor passivation portion (in which case the doped semiconductor passivation portion may be disposed on the side of the interface passivation portion away from the semiconductor substrate).

[0114] The materials and thicknesses of the doped semiconductor passivation portion and the interface passivation portion included in the island passivation structure, as well as the conductivity type of the doped semiconductor passivation portion, can be set according to actual needs and are not specifically limited here.

[0115] For example, the material and conductivity type of the doped semiconductor passivation portion can be the same as those of one of the first doped semiconductor layer and the second doped semiconductor layer. In this case, taking the example where the material and conductivity type of the doped semiconductor passivation portion included in the island passivation structure are the same as those of the second doped semiconductor layer, the island passivation structure can be manufactured simultaneously with the second doped semiconductor layer, improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process of the back contact battery.

[0116] For example, the thickness of the doped semiconductor passivation portion may be less than or equal to the thickness of one of the first doped semiconductor layer and the second doped semiconductor layer.

[0117] Specifically, the material and conductivity type of the doped semiconductor passivation portion are either the same as those of the first doped semiconductor layer or the second doped semiconductor layer. Secondly, the relationship between the thickness of the doped semiconductor passivation portion and the thicknesses of the first and second doped semiconductor layers can be determined based on the distribution of the island-shaped passivation structure on the first platform region and the relative positional relationship between the island-shaped passivation structure and the first doped semiconductor layer; no specific limitations are made here.

[0118] For example, such as Figure 3 and Figure 4 As shown, along the width direction of the spacer region 16, if the sidewall of the first doped semiconductor layer and the sidewall of the island passivation structure are adjacent, or if the island passivation structure 27 is located between the first doped semiconductor layer 12 and the spacer region 16, then the material and conductivity type of the doped semiconductor passivation portion can be the same as the material and conductivity type of either the first doped semiconductor layer 12 or the second doped semiconductor layer 13. The thickness of the doped semiconductor passivation portion can be less than or equal to the thickness of the first doped semiconductor layer 12 or the second doped semiconductor layer 13 that has the same conductivity type as the doped semiconductor passivation portion.

[0119] For example, such as Figures 9 to 14 As shown, along the width direction of the spacing region 16, if the island-shaped passivation structure (not shown in the figure) is at least partially located in the first doped semiconductor layer 12, then the material and conductivity type of the doped semiconductor passivation portion included in the island-shaped passivation structure are the same as the material and conductivity type of the second doped semiconductor layer 13. The thickness of the doped semiconductor passivation portion can be less than or equal to the thickness of the second doped semiconductor layer 13.

[0120] Of course, the material of the doped semiconductor passivation portion included in the island passivation structure can also be different from the material of the first doped semiconductor layer and / or the second doped semiconductor layer. In this case, the doped semiconductor passivation portion of the island passivation structure, as well as the first doped semiconductor layer or the second doped semiconductor layer, can be manufactured separately.

[0121] For example, the material of the interface passivation portion is the same as the material of the first interface passivation layer or the second interface passivation layer. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect described above, in which the material and conductivity type of the doped semiconductor passivation portion are the same as the material and conductivity type of one of the first doped semiconductor layer and the second doped semiconductor layer, respectively, and will not be repeated here.

[0122] For example, the thickness of the interface passivation portion can be less than or equal to the thickness of the first interface passivation layer or the second interface passivation layer.

[0123] Specifically, the material of the interface passivation portion is either the same as the material of the first interface passivation layer or the same as the material of the second interface passivation layer. Secondly, the relationship between the thickness of the interface passivation portion and the thicknesses of the first and second interface passivation layers can be determined based on the distribution of the island-shaped passivation structures on the first platform region and the relative positional relationship between the island-shaped passivation structures and the first doped semiconductor layer. The principle for determining the correspondence between the material, conductivity type, and thickness of the doped semiconductor passivation portion and the material, conductivity type, and thickness of the first and second doped semiconductor layers, as described above, can be referred to, and will not be repeated here.

[0124] Of course, the material of the interface passivation portion included in the island-shaped passivation structure can also be different from the material of the first interface passivation layer and / or the second interface passivation layer. In this case, the interface passivation portion of the island-shaped passivation structure, as well as the first interface passivation layer or the second interface passivation layer, can be manufactured separately.

[0125] When the back contact battery does not include the first interface passivation layer and / or the second interface passivation layer, the material of the interface passivation portion of the corresponding island passivation structure may include any interface passivation layer material such as silicon oxide, aluminum oxide and intrinsic silicon.

[0126] Secondly, embodiments of the present invention provide a photovoltaic module, which includes a back contact battery provided in the first aspect and various implementations thereof.

[0127] The beneficial effects of the second aspect and its various implementations in the embodiments of the present invention can be referred to the analysis of the beneficial effects of the first aspect and its various implementations, and will not be repeated here.

[0128] 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.

[0129] The embodiments of the present invention have been described above. However, these embodiments are merely for clarity and are not intended to limit the scope of the invention. The scope of the invention 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 the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A back contact cell, characterized in that, The semiconductor substrate comprises opposite first and second surfaces; the first surface comprises first and second regions and interval regions between the first and second regions, which are arranged alternately and intervally; The surface of the interval region is recessed inwardly relative to the surface of the first region in the direction from the first surface to the second surface, so as to form a groove structure; A first doped semiconductor layer is arranged at least partially on the first region; A second doped semiconductor layer is arranged on the second region; the second doped semiconductor layer and the first doped semiconductor layer are opposite in conductive type; the first and second doped semiconductor layers are arranged intervally on the first surface in the arrangement direction of the first and second regions, and at least part of the groove structure is located between the first and second doped semiconductor layers; Wherein, along the extension direction of the interval region, the first doped semiconductor layer comprises a first boundary close to the interval region; along the width direction of the interval region, the first boundary comprises a first sub-boundary located in the first region, and a second sub-boundary extending from the first region to above the groove structure and located above the groove structure. The total length of the first sub-boundary located in the first region is greater than the total length of the second sub-boundary located above the groove structure per unit length along the extension direction of the interval region.

2. The back contact cell of claim 1, wherein, The first boundary of the first doped semiconductor layer close to the interval region is in a concave-convex alternating structure, which comprises concave boundaries and convex boundaries.

3. The back contact cell of claim 1, wherein, The first sub-boundary comprises at least part of the concave boundaries, and the second sub-boundary comprises at least part of the convex boundaries.

4. The back contact cell of claim 3, wherein, The first sub-boundary comprises at least part of the concave boundaries and at least part of the convex boundaries.

5. The back contact cell of claim 3, wherein, Or, the second sub-boundary comprises at least part of the concave boundaries and at least part of the convex boundaries. The distance between adjacent concave boundaries or the distance between adjacent convex boundaries W1 is greater than or equal to 1 μm and less than or equal to 15 μm along the width direction of the interval region; 6. The back contact cell of claim 3, wherein, And / or, the extension width W2 of the first sub-boundary in the first region along the width direction of the interval region is less than or equal to 8 μm; And / or, the extension width W3 of the second sub-boundary above the groove structure along the width direction of the interval region is less than or equal to 10 μm. The groove structure has a first side wall close to the first region along the width direction of the interval region; the first region comprises a first platform region close to the first side wall along the width direction of the interval region, and the first platform region comprises a platform surface perpendicular to the thickness direction of the semiconductor substrate.

7. The back contact cell of claim 1, wherein, The first platform region further comprises a second side wall away from the first side wall and continuous with the platform surface; 8. The back contact cell of claim 7, wherein, The second side wall is arranged perpendicularly relative to the platform surface, or the second side wall is arranged obliquely relative to the platform surface. ​ 9. The back contact cell of claim 8, wherein, An included angle between the second side wall and the platform surface is greater than or equal to 30° and less than or equal to 150°.

10. The back contact cell of claim 7, wherein, The back contact cell further comprises island-shaped passivation structures arranged on the first platform region, the island-shaped passivation structures being spaced apart from the first doped semiconductor layer.

11. The back contact cell of claim 10, wherein, At least one of the island-shaped passivation structures comprises a doped semiconductor passivation part; And / or, at least one of the island-shaped passivation structures comprises an interface passivation part.

12. The back contact cell of claim 11, wherein, The material and the conductivity type of the doped semiconductor passivation part are the same as the material and the conductivity type of one of the first doped semiconductor layer and the second doped semiconductor layer, respectively. And / or, the back contact cell further comprises a first interface passivation layer arranged between the semiconductor substrate and the first doped semiconductor layer, and a second interface passivation layer arranged between the semiconductor substrate and the second doped semiconductor layer. The material of the interface passivation part is the same as the material of the first interface passivation layer or the second interface passivation layer.

13. The back contact cell according to any of claims 1 to 12, wherein, The first doped semiconductor layer is a P-type doped semiconductor layer. And / or, the first doped semiconductor layer is an emitter doped layer.

14. A photovoltaic module, characterized by, A back contact cell as claimed in any one of claims 1 to 13.

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