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, aiming to change the transmission path of light at the surface of the first region and / or the second region of the back contact cell close to the interval region through island-shaped passivation structures, and increase the bifaciality of the back contact cell. The back contact cell comprises a semiconductor substrate, a first doped semiconductor layer, a second doped semiconductor layer and island-shaped passivation structures. The first surface of the semiconductor substrate comprises a first region, a second region and an interval region. The first doped semiconductor layer has a first boundary close to the interval region. The second doped semiconductor layer and the first doped semiconductor layer are opposite in conductive type, and the second doped semiconductor layer has a second boundary close to the interval region. The island-shaped passivation structures are arranged on the semiconductor substrate. At least one island-shaped passivation structure is at least partially located between the first boundary and the first side wall; and / or, at least one island-shaped passivation structure is at least partially located between the second boundary and the second side wall.

Description

Technical Field

[0001] This application 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, the light utilization rate on the back side of existing back-contact batteries is low, which is not conducive to improving the bifaciality of back-contact batteries. Summary of the Invention

[0004] The purpose of this application is to provide a back-contact cell and a photovoltaic module, which uses an island-like passivation structure to change the light transmission path on the surface of the first region and / or the second region near the spacing region in the back-contact cell, thereby allowing more light to be refracted from the first surface into the cell, improving the light utilization rate on the back side of the back-contact cell, and increasing the bifaciality of the back-contact cell.

[0005] 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, and an island-shaped passivation structure. The semiconductor substrate has opposing first and second surfaces. The first surface includes alternately spaced first and second regions, and a gap region located between the first and second regions. Along the direction from the first to the second surface, the surface of the gap region is recessed into the semiconductor substrate relative to the surface of the first region to form a groove structure. The groove structure has a first sidewall near the first region and a second sidewall near the second region. The first doped semiconductor layer is disposed on the first region and has a first boundary near the gap region. The second doped semiconductor layer is disposed on the second region, the second doped semiconductor layer having an opposite conductivity type to the first doped semiconductor layer, and has a second boundary near the gap region. The island-shaped passivation structure is disposed on the semiconductor substrate. At least one island-shaped passivation structure is at least partially located between the first boundary and the first sidewall; and / or, at least one island-shaped passivation structure is at least partially located between the second boundary and the second sidewall.

[0006] When the back-contact battery is in operation, the first and second doped semiconductor layers can effectively shunt and collect charge carriers, facilitating the formation of photocurrent. The island-shaped passivation structure has a passivation function, passivating the surface of the region on the semiconductor substrate where the island-shaped passivation structure is formed, reducing the number of defects on the surface and lowering the carrier recombination rate. Furthermore, the island-shaped passivation structure can alter the transmission path of incident light (e.g., increasing the reflection path of incident light), allowing more incident light to be refracted into the battery, increasing the incident light absorption ratio, and improving the bifaciality of the back-contact battery. The island-shaped passivation structure is not part of the semiconductor substrate; it is an additional passivation structure formed on the semiconductor substrate in an island shape. Taking at least one island-shaped passivation structure located at least partially between the first boundary and the first sidewall as an example: the island-shaped passivation structure is away from the surface of the semiconductor substrate, and there may be a certain height difference between it and the local surface of the semiconductor substrate located between the first boundary and the first sidewall. Alternatively, the island-shaped passivation structure and the semiconductor substrate may have material differences, which allows the island-shaped passivation structure to reflect or refract incident light on one side of the first surface of the back contact battery, changing 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, increasing the incident light absorption ratio, and increasing the bifaciality of the back contact battery.

[0007] As one possible implementation, the first boundary has first sub-boundaries located within the first region and spaced apart from the first sidewalls along the width direction of the interval region, and an island-shaped passivation structure is provided between at least one first sub-boundary and the first sidewall. And / or, the second boundary has second sub-boundaries located within the second region and spaced apart from the second sidewalls along the width direction of the interval region, and an island-shaped passivation structure is provided between at least one second sub-boundary and the second sidewall.

[0008] Taking a first sub-boundary located within a first region and spaced apart from the first sidewall of the groove structure along the width direction of the interval region as an example: When the first boundary also includes the first sub-boundary, along the width direction of the interval region, there is not only an interval region between the portion of the first doped semiconductor layer corresponding to the first sub-boundary and the second doped semiconductor layer, but also, because the first sub-boundary is spaced apart from the first sidewall of the groove structure, in other words, the portion of the first doped semiconductor layer corresponding to the first sub-boundary is recessed into the first region relative to the first sidewall of the groove structure. Therefore, the distance between the first doped semiconductor layer and the second doped semiconductor layer can be increased, further reducing the risk of leakage between them. In addition, the island passivation structure is disposed on the portion of the first region that is not directly covered by the first doped semiconductor layer. This can reduce the impact of the island passivation structure on the quality and precision requirements of forming conductive electrodes on the first doped semiconductor layer. At the same time, the island passivation structure can passivate the local surfaces in the first region of the semiconductor substrate that have a large number of surface defects and high passivation requirements, which is beneficial to reducing the carrier recombination rate of the local surface and improving the conversion efficiency of the back contact battery. The second boundary has second sub-boundaries located within the second region and distributed at intervals from the second sidewalls along the width direction of the interval region. At least one second sub-boundary is provided with an island-shaped passivation structure between the second sidewall and the second sub-boundary. The function and effect of the island-shaped passivation structure are the same as those of the island-shaped passivation structure of the first sub-boundary, and will not be repeated here.

[0009] As one possible implementation, the portion of the first region near the first sidewall and not directly covered by the first doped semiconductor layer is a plateau region, and / or, the portion of the second region near the second sidewall and not directly covered by the second doped semiconductor layer is a plateau region. The plateau region includes a plane substantially parallel to the first surface. At least one island-shaped passivation structure is disposed on the plane included in the plateau region.

[0010] The platform region includes a plane that is approximately parallel to the first surface. At this time, the surface of the portion of the first region of the semiconductor substrate that is not directly covered by the first doped semiconductor layer and / or the portion of the second region that is not directly covered by the second doped semiconductor layer (i.e., the platform region) is relatively flat. On the one hand, as a transition region between the first region or the second region and the spacer region, it can effectively reduce the risk of leakage current. Moreover, by setting island-shaped passivation structures in at least a portion of the platform region, the surface of the platform region with island-shaped passivation structures can be passivated, reducing the number of defects on the surface of the region and reducing the carrier recombination rate. On the other hand, the plane of the platform region increases the light absorption area, promotes the diversification of light absorption surface morphology, and by setting island-shaped passivation structures in at least a portion of the platform region, the island-shaped passivation structures enhance light absorption, thereby comprehensively improving the light utilization rate of the back contact battery.

[0011] As one possible implementation, along the width direction of the interval region, the width of the plane included in at least one platform region is less than or equal to 1 μm.

[0012] Taking the portion of the first region near the first sidewall that is not directly covered by the first doped semiconductor layer as an example, it can be understood that the wider the plane included in the platform region, the larger the distance between the portion of the first doped semiconductor layer corresponding to the platform region and the spacing region, and the smaller the area ratio of the first doped semiconductor layer in the first region. Therefore, when the width of the plane included in at least one platform region is within the above range, it is beneficial to improve the bifaciality and passivation effect of the back contact cell through the island-like passivation structure, while allowing the first doped semiconductor layer to have a larger area ratio in the first region. This is beneficial for the first doped semiconductor layer to have a higher field passivation effect and carrier collection capability, and thus for the back contact cell to have a higher conversion efficiency. The portion of the second region near the second sidewall that is not directly covered by the second doped semiconductor layer is a platform region, and the effect of the width of the plane included in at least one platform region being less than or equal to 1 μm is the same as the effect of the width of the plane included in the platform region being less than or equal to 1 μm in the first region, and will not be repeated here.

[0013] As one possible implementation, if the first region has a platform area, at least one platform area further includes a third sidewall that is remote from the first sidewall and continuous with the plane. And / or, if the second region has a platform area, at least one platform area further includes a third sidewall that is remote from the second sidewall and continuous with the plane. The third sidewall is either perpendicular to the plane or inclined relative to the plane.

[0014] Taking a first region having a plateau region, and the plateau region also including a third sidewall, as an example: the plateau region also includes a third sidewall continuous with the plane, indicating that along the direction from the first surface to the second surface, the plane is recessed into the semiconductor substrate relative to the surface of the area directly covered by the first doped semiconductor layer in the first region. This can reduce the height difference between the bottom surface of the trench structure and the surface of the area 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, reduces the carrier recombination rate at the junction of the first region and the spacer region, enhances the diversity of light absorption surface morphology, and improves the light utilization rate of the back contact cell. The application principle of the beneficial effects of the second region having a plateau region, and the plateau region also including a third sidewall, can be referred to the application principle of the beneficial effects of the first region having a plateau region, and the plateau region also including a third sidewall, as described above, and will not be repeated here.

[0015] As one possible implementation, at least one island-shaped passivation structure further extends from the plane to at least a portion of the third sidewall. In this case, it is advantageous to increase the passivation contact area of ​​the island-shaped passivation structure on one side of the first surface, thereby improving the passivation effect of the island-shaped passivation structure. Furthermore, it is also possible to increase the surface area of ​​the island-shaped passivation structure on the side facing away from the semiconductor substrate, which is beneficial for enhancing the light-trapping effect of the first surface on which the island-shaped passivation structure is provided.

[0016] As one possible implementation, the height of the third 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.

[0017] The height of the third sidewall, within the aforementioned range, helps prevent a large height variation between the bottom surface of the groove structure and the surface of the area with greater height in the first region (and / or the second region) due to a smaller height of the third sidewall. This further enhances the passivation effect of the surface passivation layer at the junction of the first region and the spacer region, and / or at the junction of the second region and the spacer region. Additionally, it prevents a large etching amount in the semiconductor substrate corresponding to the platform region due to a larger height of the second sidewall. This allows for a greater light absorption depth in the semiconductor substrate corresponding to the platform region, improving the light utilization rate of the semiconductor substrate and further enhancing the conversion efficiency of the back contact cell.

[0018] As one possible implementation, if the first region has a plateau region, a portion of the first boundary also extends above the plane included in the plateau region, and the first doped semiconductor layer and the island passivation structure are spaced apart. And / or, if the second region has a plateau region, a portion of the second boundary also extends above the plane included in the plateau region, and the second doped semiconductor layer and the island passivation structure are spaced apart.

[0019] Taking a first region with a platform area, where a portion of the first boundary extends above the plane encompassed by the platform area, as an example: 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 plane and / or reflected from the outer surface of the island passivation structure, allowing some light to re-enter the semiconductor substrate, further improving the light utilization rate of the back contact battery. Furthermore, the alternating distribution of the first doped semiconductor layer and the island passivation structure facilitates light transmission between the outer surface of the island passivation structure and the inner surface of the portion of the first doped semiconductor layer extending above the plane. This alters the transmission path of the incident light, allowing more incident light to refract into the battery, increasing the incident light absorption ratio, and further improving the bifaciality of the back contact battery. Moreover, when the island passivation structure includes a doped semiconductor passivation portion with a conductivity type opposite to that of the first doped semiconductor layer, the alternating distribution of the first doped semiconductor layer and the island passivation structure also helps reduce the leakage risk between them, contributing to a higher conversion efficiency for the back contact battery. The application principle of the beneficial effect of the second region having a platform area and part of the second boundary extending above the plane included by the platform area can be referred to the application principle of the beneficial effect of the first region having a platform area and part of the first boundary extending above the plane included by the platform area, as described above, and will not be repeated here.

[0020] As one possible implementation, where a portion of the first boundary extends above the plane encompassed by the platform region, the spacing between the first doped semiconductor layer and the island passivation structure along the thickness direction of the semiconductor substrate is greater than or equal to 1 nm and less than or equal to 500 nm. And / or, where a portion of the second boundary extends above the plane encompassed by the platform region, the spacing between the second doped semiconductor layer and the island passivation structure along the thickness direction of the semiconductor substrate is greater than or equal to 1 nm and less than or equal to 500 nm.

[0021] Taking the spacing between the first doped semiconductor layer and the island passivation structure within the aforementioned range as an example: This facilitates effective light transmission between the outer surface of the island passivation structure and the inner surface of the portion of the first doped semiconductor layer extending above the plane. This allows these two parts to effectively coordinate in changing the transmission path of the incident light, further increasing the absorption ratio of the incident light. Furthermore, all other factors being equal, when the spacing between the first doped semiconductor layer and the island passivation structure increases, the etching amount of the portion of the semiconductor substrate corresponding to the plateau region is larger. Therefore, the spacing between the first doped semiconductor layer and the island passivation structure within the aforementioned range also allows the portion of the semiconductor substrate corresponding to the plateau region to have a larger absorption depth, improving the utilization rate of light by the semiconductor substrate. The application principle of the beneficial effects of the spacing between the second doped semiconductor layer and the island passivation structure within the aforementioned range can be referred to the application principle of the beneficial effects of the spacing between the first doped semiconductor layer and the island passivation structure within the aforementioned range described above, and will not be repeated here.

[0022] As one possible implementation, if a portion of the first boundary also extends above the plane included in the platform region, the extension width of the first boundary relative to the third sidewall is less than or equal to 1 μm along the width direction of the interval region. And / or, if a portion of the second boundary also extends above the plane included in the platform region, the extension width of the second boundary relative to the third sidewall is less than or equal to 1 μm along the width direction of the interval region.

[0023] Taking an example where a portion of the first boundary extends above the plane encompassing the platform region, and the extension width is within the aforementioned range, this can prevent the extended portion of the first doped semiconductor layer from having a weak light reflection effect due to an excessively small extension width, thus facilitating a further improvement in the bifaciality of the back-contact battery. The application principle of the beneficial effect of a portion of the second boundary extending above the plane encompassing the platform region, and the extension width being within the aforementioned range, can be referenced from the application principle of the beneficial effect of a portion of the first boundary extending above the plane encompassing the platform region, and the extension width being within the aforementioned range, as described above, and will not be repeated here.

[0024] As one possible implementation, at least one island-shaped passivation structure occupies more than 50% of the area within the plateau region. This allows the island-shaped passivation structure to have a larger area within the plateau region, enhancing its ability to adjust the light transmission path, allowing more incident light to be refracted into the battery, increasing the incident light absorption ratio, and further improving the bifaciality of the back-contact battery.

[0025] As one possible implementation, the first boundary has a first alternating concave-convex structure, and the boundaries of at least some of the concave portions in the first alternating concave-convex structure are first sub-boundaries. And / or, the second boundary has a second alternating concave-convex structure, and the boundaries of at least some of the concave portions in the second alternating concave-convex structure are second sub-boundaries.

[0026] Taking the example of a first boundary having a first alternating concave-convex structure, where the boundary of at least a portion of the concave portion in the first alternating concave-convex structure is a first sub-boundary: the first sub-boundary of the first doped semiconductor layer disposed in the first region is opposite to at least a portion of the concave portion in the first alternating concave-convex structure. This is beneficial because it makes the alternating concave-convex structure of the first boundary more closely match the fluctuation changes of the portion of the first doped semiconductor layer that is recessed into the first region. This reduces the need for increased etching of the semiconductor substrate to achieve the first boundary of the first doped semiconductor layer, which is beneficial for increasing the light absorption area of ​​the semiconductor substrate and improving the conversion efficiency of the back contact cell. The application principle of the beneficial effect of the second boundary having a second alternating concave-convex structure, where the boundary of at least a portion of the concave portion in the second alternating concave-convex structure is a second sub-boundary, can be referred to the application principle of the beneficial effect of the first boundary having a first alternating concave-convex structure, where the boundary of at least a portion of the concave portion in the first alternating concave-convex structure is a first sub-boundary as described above, and will not be repeated here.

[0027] As one possible implementation, at least a portion of the protrusions in the first and / or second alternating concave-convex structures extend over the groove structure along the width direction of the interval region.

[0028] The first doped semiconductor layer and / or the second doped semiconductor layer are partially suspended above the groove structure corresponding to at least a portion of the protrusion, which is beneficial for reflecting a portion of the light emitted from the first surface of the semiconductor substrate back to the semiconductor substrate and being reused by the semiconductor substrate, thereby improving the light utilization rate of the back contact battery.

[0029] As one possible implementation, at least one convex portion in the first alternating concave-convex structure extends with a width of less than or equal to 1 μm above the groove structure relative to the first sidewall. And / or, at least one convex portion in the second alternating concave-convex structure extends with a width of less than or equal to 1 μm above the groove structure relative to the second sidewall. The application principle of the beneficial effect in this case can be referenced to the application principle of the beneficial effect described above where a portion of the first boundary also extends above the plane included in the platform region, and the width of the first boundary extending with respect to the third sidewall is less than or equal to 1 μm; it will not be repeated here.

[0030] As one possible implementation, along the extension direction of the interval region, the first sidewall has a third alternating concave-convex structure, in which at least some of the protrusions in the third alternating concave-convex structure are staggered with adjacent protrusions in the first alternating concave-convex structure. And / or, along the extension direction of the interval region, the second sidewall has a fourth alternating concave-convex structure, in which at least some of the protrusions in the fourth alternating concave-convex structure are staggered with adjacent protrusions in the second alternating concave-convex structure.

[0031] Taking the example of at least some of the convex portions in the third alternating concave-convex structure being staggered with adjacent convex portions in the first alternating concave-convex structure, it is advantageous to set island-shaped passivation structures on the portions where the convex or concave portions of the third alternating concave-convex structure are staggered with the concave or convex portions of the first alternating concave-convex structure. This increases the bifaciality of the battery while allowing the first doped semiconductor layer to have a larger area ratio in the first region, thereby enhancing the field passivation effect and carrier collection capability of the first doped semiconductor layer. The application principle of the beneficial effect of at least some of the convex portions in the third alternating concave-convex structure being staggered with adjacent convex portions in the second alternating concave-convex structure can be referred to the application principle of the beneficial effect of at least some of the convex portions in the third alternating concave-convex structure being staggered with adjacent convex portions in the first alternating concave-convex structure described above, and will not be repeated here.

[0032] 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; and / or, at least one island passivation structure includes a doped semiconductor portion and a doped silicon glass portion disposed on the side of the doped semiconductor portion away from the semiconductor substrate.

[0033] The island-shaped passivation structure can be formed by at least three types of passivation components that offer good performance and are compatible with battery manufacturing processes: doped semiconductor passivation components, interface passivation components, and doped silicon glass components. This not only provides excellent passivation performance but also improves the yield of the back contact battery. Furthermore, since doped semiconductor passivation components, interface passivation components, and doped silicon glass components are also materials used in manufacturing back contact batteries, the island-shaped passivation structure can be manufactured simultaneously with the corresponding structure in the back contact battery, improving manufacturing efficiency and simplifying the manufacturing process.

[0034] As one possible implementation, in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the material and conductivity type of the doped semiconductor portion are the same as those of the second doped semiconductor layer; and / or, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the material and conductivity type of the doped semiconductor portion are the same as those of the first doped semiconductor layer.

[0035] When the material and conductivity type of the doped semiconductor portion in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall are the same as those of the second doped semiconductor layer, the fabrication of at least one island-shaped passivation structure disposed between the first boundary and the first sidewall can be achieved simultaneously with the fabrication of the second doped semiconductor layer, thereby improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process. The application principle of the beneficial effect of the material and conductivity type of the doped semiconductor portion in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall being the same as those of the first doped semiconductor layer can be referred to the preceding text and will not be repeated here.

[0036] 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. In at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the material of the interface passivation portion is the same as the material of the second interface passivation layer; and / or, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the material of the interface passivation portion is the same as the material of the first 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 portion in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall are the same as the material and conductivity type of the second doped semiconductor layer, and will not be repeated here.

[0037] As one possible implementation, the back contact battery further includes a first doped silicon glass layer disposed on the side of the first doped semiconductor layer facing away from the semiconductor substrate, and a second doped silicon glass layer disposed on the side of the second doped semiconductor layer facing away from the semiconductor substrate. The first doped silicon glass layer has the same conductivity type as the first doped semiconductor layer. The second doped silicon glass layer has the same conductivity type as the second doped semiconductor layer. In at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the material and conductivity type of the doped silicon glass portion are the same as those of the second doped silicon glass layer; and / or, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the material and conductivity type of the doped silicon glass portion are the same as those of the first doped silicon glass layer. The application principle of the beneficial effect in this case can refer to the application principle of the beneficial effect of the material and conductivity type of the doped semiconductor portion being the same as those of the second doped semiconductor layer in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, as described above, and will not be repeated here.

[0038] Secondly, this application provides a photovoltaic module, including a cell string and an encapsulation layer. The cell string is formed by the electrical connection of multiple back-contact cells as provided in the first aspect and its various implementations; the encapsulation layer covers the surface of the cell string.

[0039] 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

[0040] 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:

[0041] Figure 1 A longitudinal cross-sectional view of a first structure of a back-contact battery provided in an embodiment of this application;

[0042] Figure 2 SEM image of a portion of the first boundary of a back contact battery provided in an embodiment of this application. Figure 1 ;

[0043] Figure 3 SEM image of a portion of the first boundary of a back contact battery provided in an embodiment of this application. Figure 2 ;

[0044] Figure 4 SEM image of a portion of the second boundary of a back contact battery provided in an embodiment of this application;

[0045] Figure 5 A longitudinal cross-sectional view of a second structure of a back-contact battery provided in an embodiment of this application;

[0046] Figure 6 A longitudinal cross-sectional view of a third structure of a back-contact battery provided in an embodiment of this application;

[0047] Figure 7 A longitudinal cross-sectional view of a fourth structure of a back-contact battery provided in an embodiment of this application;

[0048] Figure 8 A longitudinal cross-sectional view of the fifth structure of the back contact battery provided in the embodiments of this application;

[0049] Figure 9 A longitudinal cross-sectional view of the sixth structure of the back contact battery provided in the embodiments of this application;

[0050] Figure 10 A longitudinal cross-sectional view of the seventh structure of the back contact battery provided in the embodiments of this application;

[0051] Figure 11 A longitudinal cross-sectional view of the eighth structure of the back contact battery provided in the embodiments of this application;

[0052] Figure 12 A longitudinal cross-sectional view of the ninth structure of the back contact battery provided in the embodiments of this application;

[0053] Figure 13 A longitudinal cross-sectional view of the tenth structure of the back contact battery provided in the embodiments of this application;

[0054] Figure 14 A longitudinal cross-sectional view of the eleventh structure of the back contact battery provided in the embodiments of this application;

[0055] Figure 15 A longitudinal cross-sectional schematic diagram of the twelfth structure of the back contact battery provided in the embodiments of this application;

[0056] Figure 16 A longitudinal cross-sectional view of the thirteenth structure of the back contact battery provided in this application embodiment;

[0057] Figure 17 A longitudinal cross-sectional view of the fourteenth structure of the back contact battery provided in the embodiments of this application;

[0058] Figure 18 A longitudinal cross-sectional schematic diagram of the fifteenth structure of the back contact battery provided in the embodiments of this application;

[0059] Figure 19 The OM of the partial island-shaped passivation structure disposed in the first region or the second region in the back contact battery provided in the embodiments of this application Figure 1 ;

[0060] Figure 20 The OM of the partial island-shaped passivation structure disposed in the first region or the second region in the back contact battery provided in the embodiments of this application Figure 2 ;

[0061] Figure 21 A longitudinal cross-sectional schematic diagram of the sixteenth structure of the back contact battery provided in the embodiments of this application;

[0062] Figure 22 This is a longitudinal cross-sectional schematic diagram of the seventeenth structure of the back contact battery provided in the embodiments of this application.

[0063] Reference numerals: 11 is a semiconductor substrate, 12 is a first doped semiconductor layer, 13 is a second doped semiconductor layer, 14 is an island passivation structure, 15 is a first region, 16 is a second region, 17 is a spacer region, 18 is a groove structure, 19 is a first sidewall, 20 is a second sidewall, 21 is a first boundary, 22 is a second boundary, 23 is a platform region, 24 is a plane, 25 is a third sidewall, 26 is a first sub-boundary, 27 is a second sub-boundary, 28 is a first interface passivation layer, 29 is a second interface passivation layer, 30 is a first doped silicon glass layer, and 31 is a second doped silicon glass layer. Detailed Implementation

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] However, to improve the formation quality and field passivation effect of the doped semiconductor layer on the back side of the battery, existing back-contact batteries have a relatively flat surface on the back side. However, a flat surface has poor light trapping effect, resulting in low utilization of incident light on the back side of the battery, which is not conducive to improving the bifaciality of the back-contact battery.

[0071] To address the aforementioned technical problems, in a first aspect, embodiments of this application provide a back-contact battery. For example... Figures 1 to 4As shown, the back contact battery includes: a semiconductor substrate 11, a first doped semiconductor layer 12, a second doped semiconductor layer 13, and an island passivation structure 14. The semiconductor substrate 11 has opposing first and second surfaces. The first surface includes alternating first regions 15 and second regions 16, and a spacer region 17 located between the first and second regions 15 and 16. Along the direction from the first surface to the second surface, the surface of the spacer region 17 is recessed into the semiconductor substrate 11 relative to the surface of the first region 15 to form a groove structure 18. The groove structure 18 has a first sidewall 19 near the first region 15 and a second sidewall 20 near the second region 16. The first doped semiconductor layer 12 is disposed on the first region 15 and has a first boundary 21 near the spacer region 17. The second doped semiconductor layer 13 is disposed on the second region 16, and the second doped semiconductor layer 13 has an opposite conductivity type to the first doped semiconductor layer 12. The second doped semiconductor layer 13 has a second boundary 22 near the spacer region 17. The island passivation structure 14 is disposed on the semiconductor substrate 11. Wherein, at least one island-shaped passivation structure 14 is at least partially located between the first boundary 21 and the first sidewall 19; and / or, at least one island-shaped passivation structure 14 is at least partially located between the second boundary 22 and the second sidewall 20.

[0072] When the back-contact battery is in operation, the first and second doped semiconductor layers can effectively shunt and collect charge carriers, which is beneficial for forming photocurrent. For example... Figures 1 to 4 As shown, the island-shaped passivation structure 14 has a passivation function, which can passivate the surface of the region on the semiconductor substrate 11 where the island-shaped passivation structure 14 is formed, reducing the number of defects on the surface of the region and reducing the carrier recombination rate. In addition, the island-shaped passivation structure 14 can change the transmission path of incident light (such as increasing the reflection path of incident light), which is beneficial for more incident light to be refracted into the cell, increasing the incident light absorption ratio and improving the bifaciality of the back contact cell. The island-shaped passivation structure 14 is not part of the semiconductor substrate 11; it is an additional passivation structure disposed on the semiconductor substrate 11 and has an island-shaped shape. Taking at least one island-shaped passivation structure 14 located at least partially between the first boundary 21 and the first sidewall 19 as an example: the island-shaped passivation structure 14 is away from the surface of the semiconductor substrate 11 and has a certain height difference with the local surface of the semiconductor substrate 11 located between the first boundary 21 and the first sidewall 19. Alternatively, the island-shaped passivation structure 14 and the semiconductor substrate 11 have material differences, so that the side surface of the island-shaped passivation structure 14 can reflect or refract incident light on 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.

[0073] In practical applications, 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 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.

[0074] 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.

[0075] It is understandable that one of the first and second regions roughly corresponds to the emitter region, and the other 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.

[0076] 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 this application embodiment. For example, the first and second regions can be arranged in alternating stripes or in alternating interdigitated shapes.

[0077] 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 this application embodiment. For example, the first and second regions can be arranged in alternating stripes or in alternating interdigitated shapes.

[0078] From the perspective of surface morphology, such as Figure 1 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.

[0079] 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.

[0080] Or, such as Figure 5 As shown, the surface of the spacer region 17 included in the first side can be textured to improve the light trapping effect of the spacer region 17 and increase the bifaciality of the back contact battery.

[0081] 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. Furthermore, the first and second sidewalls of the groove structure can be perpendicular to the bottom surface of the groove, or they can be inclined relative to the bottom surface of the groove. The first and second sidewalls can be planar or textured surfaces. When the first and / or second sidewalls are textured surfaces, this embodiment does not specifically limit the type and size of the textured structure provided on the first and / or second sidewalls.

[0082] 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 16 can also be recessed into the semiconductor substrate 11 relative to the surface of the first region 15. This reduces the amount of residue remaining on the second region 16 after the patterned first doped semiconductor layer 12 is applied, reducing the risk of leakage current and improving the formation quality of the second doped semiconductor layer 13. In this case, the surface of the second region 16 can be flush with the surface of the spacer region 17; or, as shown... Figure 6 As shown, the surface of the second region 16 can also be higher than the bottom surface of the trench in the spacer region 17. As for the depth to which the surface of the second region 16 is recessed into the semiconductor substrate 11, it can be set according to actual needs, and no specific limitation is made here.

[0083] In terms of boundary morphology, the first sidewall defining the spacing region has a third boundary, and the second sidewall has a fourth boundary. The morphology of the third and fourth boundaries can be determined based on the process method used to form the groove structure in the semiconductor substrate in the actual application scenario, and no specific limitation is made here.

[0084] For example, along the extension direction of the interval region, the third and / or fourth boundaries can be linear. Or, as... Figure 2 and Figure 3 As shown, the first sidewall 19 may also have a third alternating concave-convex structure, and / or, as shown in the figure. Figure 4As shown, the second sidewall 20 can also have a fourth alternating concave-convex structure; the third and / or fourth alternating concave-convex structures can be serrated, trapezoidal, zigzag, or wavy, etc. The third and / or fourth alternating concave-convex structures can be periodic structures with a certain regularity, or they can be irregular non-periodic structures with microscopic fluctuations and macroscopically roughly alternating concave and convex shapes. The dimensions and morphologies of the concave and convex parts in the third and / or fourth alternating concave-convex structures along the extension direction and width direction of the interval region 17 can be set according to actual needs, and are not specifically limited here.

[0085] Regarding the first and second doped semiconductor layers, the embodiments of this application do not specifically limit the conductivity types of the first and second doped semiconductor layers, as long as their conductivity types 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.

[0086] 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.

[0087] 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.

[0088] 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 15. Alternatively, as... Figure 7As 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 15 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.

[0089] 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, reducing the carrier recombination rate in the second region 16 of the first surface of the semiconductor substrate 11, and further improving 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.

[0090] In terms of edge morphology, such as Figures 1 to 7 As shown, along the width direction of the spacing region 17, the morphology of the first boundary 21 of the first doped semiconductor layer 12 and / or the second boundary 22 of the second doped semiconductor layer 13 can be determined according to the manufacturing process of the first doped semiconductor layer 12 and the second doped semiconductor layer 13, as well as the distribution of the island passivation structure 14 included in the back contact battery on the semiconductor substrate 11, and is not specifically limited here.

[0091] For example, the first boundary and / or the second boundary can be straight. Or, as... Figure 2 and Figure 3 As shown, the first boundary 21 can also have a first alternating concave-convex structure, and / or, as shown in the figure. Figure 4As shown, the second boundary 22 can also have a second concave-convex alternating structure; the first and / or second concave-convex alternating structures can be serrated, trapezoidal, or wavy, etc. The first and / or second concave-convex alternating structures can be periodic structures with a certain regularity, or they can be irregular non-periodic structures with microscopic fluctuations and macroscopically roughly alternating concave and convex shapes. The dimensions and morphologies of the concave and convex parts in the first and / or second concave-convex alternating structures along the extension direction and width direction of the interval region 17 can be set according to actual needs, and are not specifically limited here.

[0092] When the first sidewall has a third alternating concave-convex structure along the extension direction of the interval region, the correspondence between the concave and convex parts in the first and third alternating concave-convex structures can be determined according to the size of the island passivation structure and the leakage prevention requirements of the back contact battery in the actual application scenario, and no specific limitation is made here.

[0093] For example, such as Figure 2 and Figure 3 As shown, at least some of the protrusions in the third alternating concave-convex structure are staggered with adjacent protrusions in the first alternating concave-convex structure. This is advantageous because island-shaped passivation structures 14 are provided on the portions where the protrusions or concave parts of the third alternating concave-convex structure intersect with the concave or convex parts of the first alternating concave-convex structure. This increases the bifaciality of the battery while simultaneously allowing the first doped semiconductor layer 12 to have a larger area ratio in the first region 15, enhancing the field passivation effect and carrier collection capability of the first doped semiconductor layer 12. The number and distribution of protrusions in the third alternating concave-convex structure that are staggered with adjacent protrusions in the first alternating concave-convex structure can be determined based on the size and distribution of the island-shaped passivation structures 14 located in the first region 15 in the actual application scenario, and are not specifically limited here. Of course, at least some of the protrusions in the third alternating concave-convex structure may also have the same protrusion trend as adjacent protrusions in the first alternating concave-convex structure.

[0094] For example, such as Figure 4 As shown, when the second sidewall 20 has a fourth alternating concave-convex structure, at least some of the protrusions in the fourth alternating concave-convex structure can be staggered with adjacent protrusions in the second alternating concave-convex structure. The application principle of the beneficial effects in this case can be referred to the previous text and will not be repeated here. The number and distribution of protrusions in the fourth alternating concave-convex structure that are staggered with adjacent protrusions in the second alternating concave-convex structure can be determined based on the size and distribution of the island-shaped passivation structure 14 located on the second region 16 in the actual application scenario, and are not specifically limited here. Of course, at least some of the protrusions in the fourth alternating concave-convex structure may also have the same protruding tendency as adjacent protrusions in the second alternating concave-convex structure.

[0095] In some cases, such as Figure 2 and Figure 3 As shown, the first boundary 21 may have first sub-boundaries 26 located within the first region 15 and spaced apart from the first sidewall 19 along the width direction of the spacing region 17, and at least one first sub-boundary 26 and the first sidewall 19 are provided with an island-shaped passivation structure 14. And / or, as... Figure 4 As shown, the second boundary 22 has a second sub-boundary 27 located within the second region 16 and spaced apart from the second sidewall 20 along the width direction of the interval region 17, and an island-shaped passivation structure 14 is provided between at least one second sub-boundary 27 and the second sidewall 20.

[0096] like Figure 2 and Figure 3 As shown, taking a first sub-boundary 26 located within the first region 15 and spaced apart from the first sidewall 19 of the groove structure 18 along the width direction of the spacing region 17 as an example: When the first boundary 21 also includes the first sub-boundary 26, along the width direction of the spacing region 17, there is not only a spacing region 17 between the portion of the first doped semiconductor layer 12 corresponding to the first sub-boundary 26 and the second doped semiconductor layer 13, but also because the first sub-boundary 26 is spaced apart from the first sidewall 19 of the groove structure 18, in other words, the portion of the first doped semiconductor layer 12 corresponding to the first sub-boundary 26 is recessed into the first region 15 relative to the first sidewall 19 of the groove structure 18. Therefore, the distance between the first doped semiconductor layer 12 and the second doped semiconductor layer 13 can be increased, further reducing the risk of leakage between them. In addition, the island passivation structure 14 is disposed on the part of the first region 15 that is not directly covered by the first doped semiconductor layer 12. This can reduce the impact of the presence of the island passivation structure 14 on the quality and precision requirements of the conductive electrode formed on the first doped semiconductor layer 12. At the same time, the presence of the island passivation structure 14 can passivate the local surface in the first region 15 of the semiconductor substrate 11 that has a large number of surface defects and a high passivation requirement, which is beneficial to reducing the carrier recombination rate of the local surface and improving the conversion efficiency of the back contact battery.

[0097] The distribution range and location of the first and second sub-boundaries within the first and second boundaries, respectively, can be determined based on the size and distribution of the island-shaped passivation structures located in the first and second regions in the actual application scenario. No specific limitations are made here.

[0098] For example, such as Figure 2 and Figure 3 As shown, when the first boundary 21 has a first alternating concave-convex structure, the boundary of at least a portion of the concave portion in the first alternating concave-convex structure can be a first sub-boundary 26; and / or, as shown Figure 4As shown, when the second boundary 22 has a second concave-convex alternating structure, the boundary of at least a portion of the concave portion in the second concave-convex alternating structure can be a second sub-boundary 27.

[0099] Taking the example of a first boundary having a first concave-convex alternating structure, and the boundary of at least a portion of the concave portion in the first concave-convex alternating structure being a first sub-boundary: the first sub-boundary of the first doped semiconductor layer disposed in the first region is opposite to at least a portion of the concave portion in the first concave-convex alternating structure. This is beneficial to make the concave-convex alternating structure of the first boundary more matched with the fluctuation change of the portion of the first doped semiconductor layer that is recessed into the first region. This can reduce the amount of etching required on the semiconductor substrate to make the first boundary of the first doped semiconductor layer have a certain degree of light absorption, which is beneficial to increase the light absorption area of ​​the semiconductor substrate and improve the conversion efficiency of the back contact battery.

[0100] In practical applications, such as Figure 2 and Figure 3 As shown, only a portion of the concave boundary in the first alternating concave-convex structure may be the first sub-boundary 26. In this case, a portion of the concave boundary may be aligned with the first sidewall 19 of the groove structure 18. Alternatively, a portion of the concave boundary in the first alternating concave-convex structure may extend above the groove structure 18. Of course, all the concave boundaries in the first alternating concave-convex structure may also be the first sub-boundary 26.

[0101] like Figure 2 and Figure 3 ,as well as Figure 12 As shown, the protrusions in the first alternating concave-convex structure may be at least partially extended along the width direction of the interval region to the top of the groove structure; or, in the first alternating concave-convex structure, some protrusion boundaries may be aligned with the first sidewall 19 of the groove structure; or, in the first alternating concave-convex structure, some protrusion boundaries may be located within the first region (i.e., some protrusion boundaries may be the first sub-boundary 26); of course, all protrusion boundaries in the first alternating concave-convex structure may extend along the width direction of the interval region to the top of the groove structure.

[0102] When the first doped semiconductor layer is partially suspended above the groove structure corresponding to at least a portion of the protrusion, it is beneficial to reflect a portion of the light emitted from the first surface of the semiconductor substrate back to the semiconductor substrate and reuse it, thereby improving the light utilization rate of the back contact cell.

[0103] As for the second alternating concave-convex structure, such as Figure 4As shown, only some of the concave boundaries in the second concave-convex alternating structure may be second sub-boundaries 27. In this case, some concave boundaries are aligned with the second sidewall 20 of the groove structure. Alternatively, some concave boundaries in the second concave-convex alternating structure may extend above the groove structure. Of course, all concave boundaries in the second concave-convex alternating structure may be second sub-boundaries 27.

[0104] like Figure 4 As shown, the protrusions in the second alternating concave-convex structure may be at least partially extended along the width direction of the interval region to the top of the groove structure; or, in the second alternating concave-convex structure, some protrusion boundaries may be aligned with the second sidewall 20 of the groove structure; or, in the second alternating concave-convex structure, some protrusion boundaries may be located within the second region (i.e., some protrusion boundaries may be the second sub-boundary 27); of course, all protrusion boundaries in the second alternating concave-convex structure may extend along the width direction of the interval region to the top of the groove structure.

[0105] The application principle of the beneficial effect when the second doped semiconductor layer is partially suspended above the groove structure corresponding to at least a portion of the protrusion can be referred to the application principle of the beneficial effect when the first doped semiconductor layer is partially suspended above the groove structure, as described above, and will not be repeated here.

[0106] As for the extension width of at least one protrusion in the first alternating concave-convex structure relative to the first sidewall above the groove structure, and / or the extension width of at least one protrusion in the second alternating concave-convex structure relative to the second sidewall above the groove structure, it can be determined according to the requirements of the bifaciality and leakage risk of the back contact battery in the actual application scenario, and no specific limitation is made here.

[0107] For example, the extension width of at least one protrusion in the first alternating concave-convex structure relative to the first sidewall above the groove structure can be less than or equal to 1 μm. For instance, the extension width of at least one protrusion in the first alternating concave-convex structure relative to the first sidewall above the groove structure can be 5 nm, 10 nm, 100 nm, 200 nm, 300 nm, 500 nm, 800 nm, or 1 μm, etc., to further improve the bifaciality of the back contact battery while making the back contact battery have a lower risk of leakage.

[0108] For example, the extension width of at least one protrusion in the second alternating concave-convex structure relative to the second sidewall above the groove structure can be less than or equal to 1 μm. For instance, the extension width of at least one protrusion in the first alternating concave-convex structure relative to the first sidewall above the groove structure can be 5 nm, 10 nm, 100 nm, 200 nm, 300 nm, 500 nm, 800 nm, or 1 μm, etc., to further improve the bifaciality of the back contact battery while ensuring a lower risk of leakage.

[0109] For example, such as Figure 2 and Figure 3 As shown, the portion of the first region 15 near the first sidewall 19 and not directly covered by the first doped semiconductor layer 12 is the plateau region 23, and / or, as shown... Figure 4 As shown, the portion of the second region 16 that is near the second sidewall 20 and not directly covered by the second doped semiconductor layer 13 is the plateau region 23. It should be noted that the plateau region 23 is a broad term, specifically referring to a region, namely the region in the first region 15 that is near the first sidewall 19 and not directly covered by the first doped semiconductor layer 12, and / or the region in the second region 16 that is near the second sidewall 20 and not directly covered by the second doped semiconductor layer 13.

[0110] like Figures 2 to 4 As shown, the platform region 23 may include a plane 24 that is substantially parallel to the first surface. In this case, the surface of the portion of the first region 15 of the semiconductor substrate 11 that is not directly covered by the first doped semiconductor layer 12 and / or the portion of the second region 16 that is not directly covered by the second doped semiconductor layer 13 (i.e., the platform region 23) is relatively flat. On the one hand, as a transition region between the first region 15 or the second region 16 and the spacer region 17, it can effectively reduce the risk of leakage. Moreover, by setting island-shaped passivation structures 14 in at least a portion of the platform region 23, the surface of the platform region 23 with island-shaped passivation structures 14 can be passivated, reducing the number of defects on the surface of the region and reducing the carrier recombination rate. On the other hand, the plane 24 of the platform region 23 increases the light absorption area, promotes the diversification of the light absorption surface morphology, and by setting island-shaped passivation structures 14 in at least a portion of the platform region 23, the island-shaped passivation structures 14 enhance light absorption, thereby comprehensively improving the light utilization rate of the back contact battery. It should be noted that if the angle between the plane 24 included in the platform area 23 and the other surfaces of the first surface is less than or equal to 5°, the plane 24 can be considered to be approximately parallel to the first surface.

[0111] Alternatively, the platform area may include a plane that forms an angle (greater than 5° and less than the inclination angle of the first and / or second sidewalls relative to the bottom of the tank) with respect to the first surface. Furthermore, the surface included in the platform area can be a relatively flat plane, or an uneven surface with a pyramidal or perforated structure. The morphology of the surface included in the platform area can be set according to actual needs and is not specifically limited here.

[0112] In terms of distribution location, when the first boundary has a first alternating concave-convex structure and the first region has a platform area, the platform area can be located between at least a portion of the concave-convex structure and the first sidewall. Alternatively, as... Figure 2 and Figure 3 As shown, the platform region 23 can be located below at least a portion of the protrusions in the first alternating concave-convex structure. Alternatively, the platform region 23 may also exist between the concave portion and the first sidewall 19 in the first alternating concave-convex structure, and below at least a portion of the protrusions in the first alternating concave-convex structure. The specific distribution of the platform region 23 can be set according to actual needs, and is not specifically limited here.

[0113] As for the case where the second boundary has a second alternating concave-convex structure and the second region has a platform area, the distribution of the platform area in the second region can be referred to the distribution of the platform area in the case where the first boundary has a first alternating concave-convex structure and the first region has a platform area, as described above, and will not be repeated here.

[0114] like Figure 2 and Figure 4 As shown, at least one island-shaped passivation structure 14 of the back contact battery can be at least partially disposed on the plane 24 of the platform region 23. In this case, the size of the plane 24 of the platform region 23 will affect the size of the island-shaped passivation structure 14. Therefore, the size and morphology of the plane 24 of the platform region 23 can be determined according to the size requirements of the island-shaped passivation structure 14 in the actual application scenario, and no specific limitation is made here.

[0115] For example, along the width direction of the spacer region, the width of the plane included in at least one platform region is less than or equal to 1 μm. For example, the width of the plane included in at least one platform region can be 10 nm, 50 nm, 100 nm, 300 nm, 500 nm, 800 nm, or 1 μm, etc. In this case, taking the portion of the first region near the first sidewall that is not directly covered by the first doped semiconductor layer as an example, it can be understood that the larger the width of the plane included in the platform region, the larger the distance between the portion of the first doped semiconductor layer corresponding to the platform region and the spacer region, and the smaller the area ratio of the first doped semiconductor layer in the first region. Therefore, when the width of the plane included in at least one platform region is within the above range, it is beneficial to improve the bifaciality and passivation effect of the back contact cell through the island-like passivation structure, while making the first doped semiconductor layer have a larger area ratio in the first region, thereby benefiting the first doped semiconductor layer to have a higher field passivation effect and carrier collection capability, and thus benefiting the back contact cell to have a higher conversion efficiency.

[0116] In terms of surface height, such as Figure 8 and Figure 13 As shown, the plane 24 included in the platform area 23 can be flush with the first surface.

[0117] Or, such as Figures 9 to 11 ,as well as Figures 13 to 15 As shown, when the first region 15 has a platform region 23, at least one platform region 23 further includes a third sidewall 25 that is remote from the first sidewall 19 and continuous with the plane 24; and / or, when the second region 16 has a platform region 23, at least one platform region 23 further includes a third sidewall 25 that is remote from the second sidewall 20 and continuous with the plane 24. The third sidewall 25 is disposed perpendicular to the plane 24, or the third sidewall 25 is disposed inclined relative to the plane 24.

[0118] Taking a first region having a platform region, and the platform region also including a third sidewall as an example: the platform region also includes a third sidewall that is continuous with the plane, indicating that along the direction from the first surface to the second surface, the plane 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, reduces the carrier recombination rate at the junction of the first region and the spacer region, improves the diversity of the light absorption surface morphology, and improves the light utilization rate of the back contact cell.

[0119] In cases where the platform area also includes a third sidewall, such as Figure 3 and Figure 4As shown, at least one island-shaped passivation structure 14 may be disposed only on the plane 24 of the platform region 23. Alternatively, as... Figure 2 As shown, at least one island-shaped passivation structure 14 can also extend from the plane 24 to at least a portion of the third sidewall 25. In this case, it is advantageous to increase the passivation contact area of ​​the island-shaped passivation structure 14 on the first side, thereby improving the passivation effect of the island-shaped passivation structure 14. Furthermore, it is also advantageous to increase the surface area of ​​the island-shaped passivation structure 14 on the side facing away from the semiconductor substrate 11, thereby enhancing the light-trapping effect of the first side on which the island-shaped passivation structure 14 is provided. The extension range of the island-shaped passivation structure 14 on the third sidewall 25 can be set according to actual needs, and is not specifically limited here.

[0120] In cases where the plateau region also includes a third sidewall, a portion of the sidewalls of the first doped semiconductor layer and / or the second doped semiconductor layer may be aligned with the third sidewall of at least one adjacent plateau region. Alternatively, as Figure 4 , Figures 9 to 11 ,as well as Figures 13 to 15 As shown, a portion of the first boundary 21 and / or the second boundary 22 may extend above the plane 24. In this case, when a portion of the sidewalls of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 are aligned with the third sidewall 25 of at least one adjacent platform region 23, it is advantageous to increase the relatively large spacing between the first doped semiconductor layer 12 and the second doped semiconductor layer 13, which is advantageous to further reduce the leakage risk between them. When a portion of the first boundary 21 and / or the second boundary 22 may extend above the plane 24, taking the first region 15 having a platform region 23 and a portion of the first boundary 21 extending above the plane 24 included in the platform region 23 as an example: although the spacing between this portion of the first boundary 21 and the second doped semiconductor layer 13 is relatively small, the portion of the first doped semiconductor layer 12 corresponding to this portion of the first boundary 21 can reflect a portion of the light emitted from the plane 24 and / or reflected from the outer surface of the island passivation structure 14, so that a portion of the light can re-enter the semiconductor substrate 11, further improving the light utilization rate of the back contact battery.

[0121] In addition, such as Figure 3 and Figure 4As shown, the first doped semiconductor layer 12 and the island passivation structure 14 can be spaced apart, which facilitates the transmission of light between the outer surface of the island passivation structure 14 and the inner surface of the portion of the first doped semiconductor layer 12 extending above the plane 24. This alters the transmission path of the incident light, allowing more incident light to be refracted into the battery, increasing the incident light absorption ratio, and further improving the bifaciality of the back contact battery. Furthermore, when the island passivation structure 14 includes a doped semiconductor passivation portion with a conductivity type opposite to that of the first doped semiconductor layer 12, the spaced distribution of the first doped semiconductor layer 12 and the island passivation structure 14 also helps reduce the leakage risk between them, resulting in higher conversion efficiency for the back contact battery. Secondly, when the second boundary 22 extends above the plane 24, the second doped semiconductor layer 13 and the island passivation structure 14 can also be spaced apart. The beneficial effects in this case can be referred to the previous text and will not be repeated here.

[0122] Of course, when an island passivation structure is provided in the first region, the sidewalls of the first doped semiconductor layer and the sidewalls of the island passivation structure can also be adjacent to each other; and / or, when an island passivation structure is provided in the second region, the sidewalls of the second doped semiconductor layer and the sidewalls of the island passivation structure can also be adjacent to each other.

[0123] As for the height of the aforementioned third sidewall, the spacing between the corresponding doped semiconductor layer and the island passivation structure, and the extension width of the first boundary and / or the second boundary above the plane, when part of the first boundary and / or the second boundary also extends above the plane, can be determined according to the requirements of the bifaciality and leakage risk of the back contact battery in the actual application scenario, and no specific limitation is made here.

[0124] For example, along the thickness direction of the semiconductor substrate, the height of the third sidewall is greater than or equal to 0.05 μm and less than or equal to 8 μm. For instance, the height of the third sidewall can be 0.05 μm, 0.1 μm, 1 μm, 2 μm, 3 μm, 5 μm, 6 μm, 7 μm, or 8 μm, etc. A height within this range helps prevent a large height variation between the bottom surface of the groove structure and the surface of the area with greater height in the first region (and / or the second region) due to a small third sidewall height. This further improves the passivation effect of the surface passivation layer at the junction of the first region and the spacer region, and / or at the junction of the second region and the spacer region. Additionally, it prevents a large etching amount in the corresponding plateau region of the semiconductor substrate due to a large second sidewall height, resulting in a larger light absorption depth in the corresponding plateau region of the semiconductor substrate. This improves the light utilization rate of the semiconductor substrate and further enhances the conversion efficiency of the back contact cell.

[0125] For example, when a portion of the first boundary extends above the plane including the platform region, the spacing between the first doped semiconductor layer and the island passivation structure is greater than or equal to 1 nm and less than or equal to 500 nm along the thickness direction of the semiconductor substrate. And / or, when a portion of the second boundary extends above the plane including the platform region, the spacing between the second doped semiconductor layer and the island passivation structure is greater than or equal to 1 nm and less than or equal to 500 nm along the thickness direction of the semiconductor substrate. Taking the spacing between the first doped semiconductor layer and the island passivation structure within the above range as an example, this facilitates effective light transmission between the outer surface of the island passivation structure and the inner surface of the portion of the first doped semiconductor layer extending above the plane, allowing these two portions to effectively cooperate in changing the transmission path of the incident light, further improving the absorption ratio of the incident light. Furthermore, with other factors remaining the same, when the spacing between the first doped semiconductor layer and the island passivation structure increases, the etching amount of the portion of the semiconductor substrate corresponding to the plateau region is larger. Therefore, within the above-mentioned range, the spacing between the first doped semiconductor layer and the island passivation structure can also enable the portion of the semiconductor substrate corresponding to the plateau region to have a larger absorption depth, thereby improving the utilization rate of light by the semiconductor substrate.

[0126] For example, when a portion of the first boundary extends above the plane included in the platform region, the extension width of the first boundary relative to the third sidewall is less than or equal to 1 μm along the width direction of the spacing region. And / or, when a portion of the second boundary extends above the plane included in the platform region, the extension width of the second boundary relative to the third sidewall is less than or equal to 1 μm along the width direction of the spacing region. Taking the example of a portion of the first boundary extending above the plane included in the platform region and the extension width being within the above range: this can prevent the extended portion of the first doped semiconductor layer from having a weak light reflection effect due to an excessively small extension width, which is beneficial for further improving the bifaciality of the back contact battery.

[0127] For example, when a portion of the first boundary extends above the plane included in the platform region, the extension width of the first boundary relative to the third sidewall can be greater than or equal to 10 nm along the width direction of the spacing region. And / or, when a portion of the second boundary extends above the plane included in the platform region, the extension width of the second boundary relative to the third sidewall can be greater than or equal to 10 nm along the width direction of the spacing region. Taking the example of a portion of the first boundary extending above the plane included in the platform region and the extension width being within the above range: this can prevent the manufacturing process of the back contact battery from becoming too difficult due to excessive extension width, and the reduction in leakage risk between the extended portion of the first doped semiconductor layer and the second doped semiconductor layer is small, which is beneficial to further improve the conversion efficiency and yield of the contact battery.

[0128] For example, if a portion of the first boundary extends above the plane included in the platform region, the extension width of the first boundary relative to the third sidewall along the width direction of the interval region can be 10nm, 20nm, 50nm, 100nm, 200nm, 500nm, 800nm, or 1μm, etc.

[0129] For example, if a portion of the second boundary extends above the plane included in the platform region, the extension width of the second boundary relative to the third sidewall along the width direction of the interval region can be 10nm, 20nm, 50nm, 100nm, 200nm, 500nm, 800nm, or 1μm, etc.

[0130] For island-shaped passivation structures, from a morphological perspective, such as Figure 20 As shown, at least one island-shaped passivation structure 14 may include multiple non-adjacent and aggregated point-like passivation portions. In this case, it is beneficial to increase the specific surface area of ​​a single island-shaped passivation structure 14, enhance the light-trapping effect of the island-shaped passivation structure 14, 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 14, 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 may be roughly regular hemispherical, circular / pyramidal, circular / frustum, circular / prism, or mountain-like shapes, or they may be irregular shapes with uneven surfaces.

[0131] Or, such as Figures 2 to 4 As shown, at least one island-shaped passivation structure 14 can also be an integral structure with its different regions continuously distributed. This can provide another example of the morphology of the island-shaped passivation structure 14, improving the applicability of the back contact battery provided in this application embodiment in different application scenarios and reducing the manufacturing difficulty of the back contact battery. In this case, the island-shaped passivation structure 14 can have a relatively flat surface (at this time, the morphology of the island-shaped passivation structure 14 can refer to the morphology of the regularly shaped dot-shaped passivation portion described above); or, the surface of the island-shaped passivation structure 14 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 effect when the different regions of at least one island-shaped passivation structure 14 are continuously distributed and the surface of the island-shaped passivation structure 14 has an undulating morphology can refer to the application principle of the beneficial effect when the island-shaped passivation structure 14 includes multiple non-adjacent and clustered dot-shaped passivation portions described above. It should be noted that Figure 20 The black oval outline in the image is a line drawn to show the approximate location of the island passivation structure 14 and is not part of the battery structure.

[0132] 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... Figures 2 to 4 As shown, at least one island-shaped passivation structure 14 has an irregularly shaped edge, which is beneficial for the island-shaped passivation structure 14 to have side surfaces arranged in different directions, thereby reflecting or refracting 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 14 can be determined based on the three-dimensional morphology of the island-shaped passivation structure 14 described above, and is not specifically limited here.

[0133] 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.

[0134] In terms of size, the embodiments of this application 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.

[0135] 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. The area occupied by at least one island-shaped passivation structure is 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 achieving a higher bifaciality of the back-contact battery. Furthermore, it also prevents the area occupied by the island-shaped passivation structure from being too large (the beneficial effects of preventing the area occupied by the island-shaped passivation structure from being too large can be referred to the preceding text, and will not be repeated here).

[0136] For example, at least one island-shaped passivation structure occupies more than 50% of the area within the plateau region. For instance, the area proportion of at least one island-shaped passivation structure within the plateau region can be 51%, 55%, 60%, 70%, 75%, 80%, 85%, or 90%, etc. This is beneficial because a larger area proportion of the island-shaped passivation structure within the plateau region enhances its ability to adjust the light transmission path, allows more incident light to be refracted into the battery, increases the incident light absorption ratio, and further improves the bifaciality of the back-contact battery.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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 application.

[0141] For example, 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; and / or, at least one island passivation structure includes a doped semiconductor portion and a doped silicon glass portion disposed on the side of the doped semiconductor portion away from the semiconductor substrate.

[0142] The island-shaped passivation structure can be formed by at least three types of passivation components that offer good performance and are compatible with battery manufacturing processes: doped semiconductor passivation components, interface passivation components, and doped silicon glass components. This not only provides excellent passivation performance but also improves the yield of the back contact battery. Furthermore, since doped semiconductor passivation components, interface passivation components, and doped silicon glass components are also materials used in manufacturing back contact batteries, the island-shaped passivation structure can be manufactured simultaneously with the corresponding structure in the back contact battery, improving manufacturing efficiency and simplifying the manufacturing process.

[0143] It should be noted that the island passivation structure may include only the doped semiconductor passivation portion, or only the interface passivation portion, or the island passivation structure may include 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), or the island passivation structure may include only the doped semiconductor passivation portion and the doped silicon glass portion, or the island passivation structure may simultaneously include the interface passivation portion, the doped semiconductor passivation portion, and the doped silicon glass portion (in which case the interface passivation portion, the doped semiconductor passivation portion, and the doped silicon glass portion may be stacked sequentially along the direction away from the semiconductor substrate).

[0144] The materials and thicknesses of the doped semiconductor passivation portion, the interface passivation portion, and the doped silicon glass portion included in the island passivation structure, as well as the conductivity types of the doped semiconductor passivation portion and the doped silicon glass portion, can be determined according to actual needs and are not specifically limited here.

[0145] For example, in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the material and conductivity type of the doped semiconductor portion are the same as those of the second doped semiconductor layer; and / or, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the material and conductivity type of the doped semiconductor portion are the same as those of the first doped semiconductor layer.

[0146] When the material and conductivity type of the doped semiconductor portion in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall are the same as those of the second doped semiconductor layer, the fabrication of at least one island-shaped passivation structure disposed between the first boundary and the first sidewall can be achieved simultaneously with the fabrication of the second doped semiconductor layer, thereby improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process. The application principle of the beneficial effect of the material and conductivity type of the doped semiconductor portion in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall being the same as those of the first doped semiconductor layer can be referred to the preceding text and will not be repeated here.

[0147] For example, in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the thickness of the doped semiconductor portion may be less than or equal to the thickness of the second doped semiconductor layer; and / or, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the thickness of the doped semiconductor portion may be less than or equal to the thickness of the first doped semiconductor layer.

[0148] Of course, the material and / or conductivity type of the doped semiconductor passivation portion included in the at least one island-shaped passivation structure disposed between the first boundary and the first sidewall can also be different from the material and / or conductivity type of the second doped semiconductor layer. In this case, the doped semiconductor passivation portion included in the at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, and the second doped semiconductor layer can be manufactured separately. The material and / or conductivity type of the doped semiconductor passivation portion included in the at least one island-shaped passivation structure disposed between the second boundary and the second sidewall can also be different from the material and / or conductivity type of the first doped semiconductor layer.

[0149] As for the interface passivation portion included in at least one island-shaped passivation structure, as mentioned above, when the back contact battery also includes a first interface passivation layer, the material of the interface passivation portion in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall is the same as the material of the second interface passivation layer; this is beneficial to improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process of the back contact battery.

[0150] For example, in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the thickness of the interface passivation portion is less than or equal to the thickness of the second interface passivation layer.

[0151] For example, when the back contact battery further includes a second interface passivation layer, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the material of the interface passivation portion is the same as the material of the first interface passivation layer. This is beneficial for improving the manufacturing efficiency of the back contact battery and simplifying the manufacturing process.

[0152] For example, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the thickness of the interface passivation portion is less than or equal to the thickness of the first interface passivation layer.

[0153] Of course, the material of the interface passivation portion of the at least one island-shaped passivation structure disposed between the first boundary and the first sidewall can also be different from the material of the second interface passivation layer. In this case, the interface passivation portion of the at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, and the second interface passivation layer can be manufactured separately. The material of the interface passivation portion of the at least one island-shaped passivation structure disposed between the second boundary and the second sidewall can also be different from the material of the second interface passivation layer.

[0154] 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.

[0155] Regarding the doped silicon glass portion included in at least one island-like passivation structure, exemplarily, such as Figure 16 As shown, the back contact battery may further include a first doped silicon glass layer 30 disposed on the side of the first doped semiconductor layer 12 facing away from the semiconductor substrate 11. The first doped silicon glass layer 30 has the same conductivity type as the first doped semiconductor layer 12. This passivates the side of the first doped semiconductor layer 12 facing away from the semiconductor substrate 11 and prevents the first doped semiconductor layer 12 from being affected during the fabrication of the second doped semiconductor layer 13, thus improving the first doped semiconductor layer 12's carrier shunting and collection capabilities. This application embodiment does not specifically limit the doping concentration and thickness of the impurities in the first doped silicon glass layer 30. In this case, in at least one island-shaped passivation structure 14 disposed between the second boundary 22 and the second sidewall 20, the material and conductivity type of the doped silicon glass portion can be the same as those of the first doped silicon glass layer 30. This improves the manufacturing efficiency of the back contact battery and simplifies the manufacturing process.

[0156] For example, in at least one island-shaped passivation structure disposed between the second boundary and the second sidewall, the thickness of the doped silicon glass portion may be less than or equal to the thickness of the first doped silicon glass layer.

[0157] For example, such as Figure 16 As shown, the back contact battery may further include a second doped silicon glass layer 31 disposed on the side of the second doped semiconductor layer 13 facing away from the semiconductor substrate 11. The second doped silicon glass layer 31 has the same conductivity type as the second doped semiconductor layer 13. Passivating the side of the second doped semiconductor layer 13 facing away from the semiconductor substrate 11 is beneficial for the second doped semiconductor layer 13 to have higher carrier shunting and collection capabilities. In this embodiment, the doping concentration and thickness of the impurities in the second doped silicon glass layer 31 are not specifically limited. In this case, in at least one island-shaped passivation structure 14 disposed between the first boundary 21 and the first sidewall 19, the material and conductivity type of the doped silicon glass portion can be the same as the material and conductivity type of the second doped silicon glass layer 31. This improves the manufacturing efficiency of the back contact battery and simplifies the manufacturing process.

[0158] For example, in at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, the thickness of the doped silicon glass portion may be less than or equal to the thickness of the second doped silicon glass layer.

[0159] Of course, the material and / or conductivity type of the doped silicon glass portion of the at least one island-shaped passivation structure disposed between the first boundary and the first sidewall can also be different from the material and / or conductivity type of the second doped silicon glass layer. In this case, the doped silicon glass portion of the at least one island-shaped passivation structure disposed between the first boundary and the first sidewall, and the second doped silicon glass layer can be manufactured separately. The material and / or conductivity type of the doped silicon glass portion of the at least one island-shaped passivation structure disposed between the second boundary and the second sidewall can also be different from the material and / or conductivity type of the first doped silicon glass layer.

[0160] In terms of formation location, the island-shaped passivation structure included in the back contact battery can be disposed only partially between the first boundary and the first sidewall, only between the second boundary and the second sidewall, or simultaneously between the first boundary and the first sidewall, and between the second boundary and the second sidewall. This application does not specifically limit the formation location of the island-shaped passivation structure; it can be determined based on the actual application scenario and the actual manufacturing process.

[0161] In some examples, such as Figures 17 to 20 As shown, the back-contact battery includes at least one island-shaped passivation structure 14 disposed on the side of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 facing away from the semiconductor substrate 11, and / or, the island-shaped passivation structure 14 is disposed between the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 and the semiconductor substrate 11. This passivates the surface of the region where the island-shaped passivation structure 14 is formed, reducing the number of defects on the surface of the region and reducing the carrier recombination rate; on the other hand, it can change the transmission path of incident light (e.g., increasing the reflection path of incident light), which is beneficial for more incident light to be refracted into the battery, increasing the incident light absorption ratio and improving the bifaciality of the back-contact battery. It should be noted that... Figure 19 The black oval outline in the image is a line drawn to show the approximate location of the island passivation structure 14 and is not part of the battery structure.

[0162] It should be noted that, as Figure 17 and Figure 21 As shown, when the island-shaped passivation structure 14 is disposed on the side of the first doped semiconductor layer 12 away from the semiconductor substrate 11, the island-shaped passivation structure 14 is not part of the first doped semiconductor layer 12; it is an additional passivation structure disposed on the side of the first doped semiconductor layer 12 away from the semiconductor substrate 11, and is shaped like an island. Figure 18 and Figure 22 As shown, when the island-shaped passivation structure 14 is disposed on the side of the second doped semiconductor layer 13 facing away from the semiconductor substrate 11, the island-shaped passivation structure 14 is not part of the second doped semiconductor layer 13, but is an additional passivation structure disposed outside the second doped semiconductor layer. Figure 18As shown, when the island-shaped passivation structure 14 is disposed between the first doped semiconductor layer 12 and the semiconductor substrate 11, the island-shaped passivation structure 14 belongs neither to the first doped semiconductor layer 12 nor to the semiconductor substrate 11, and is an additional passivation structure disposed outside the second doped semiconductor layer. Figure 17 and Figure 18 As shown, when the island passivation structure 14 is disposed between the second doped semiconductor layer 13 and the semiconductor substrate 11, the island passivation structure 14 belongs neither to the second doped semiconductor layer 13 nor to the semiconductor substrate 11, and is an additional passivation structure disposed outside the second doped semiconductor layer.

[0163] Information regarding the morphology, size, area, structure, and materials of the island passivation structures disposed on the side of the first doped semiconductor layer and / or the second doped semiconductor layer away from the semiconductor substrate, and / or disposed between the first doped semiconductor layer and / or the second doped semiconductor layer and the semiconductor substrate, can be found in the previous section regarding the morphology, size, area, structure, and materials of the island passivation structures disposed between the first boundary and the first sidewall, and / or disposed between the second boundary and the second sidewall. This will not be repeated here.

[0164] In terms of distribution, the island-shaped passivation structures disposed in the first and second regions of the back contact battery can be randomly distributed. Optionally, such as... Figure 19 and Figure 20 As shown, in the island-shaped passivation structures disposed in the first and second regions, at least some of the island-shaped passivation structures 14 can be regularly distributed. In this case, the distribution pattern can be set according to the interaction characteristics between the incident light and the island-shaped passivation structures 14, so that the incident light on the first side of the back contact battery is regularly reflected or refracted. Combined with the irregular light trapping effect of the island-shaped passivation structures themselves, the utilization of the incident light is maximized, which is also conducive to further improving the light trapping effect of the island-shaped passivation structures 14. Alternatively, because the island-shaped passivation structures 14 are disposed between the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 and the semiconductor substrate 11, the side of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 away from the semiconductor substrate 11 has a high light trapping effect, reducing the light blocking effect and further improving the incident light absorption ratio and the bifaciality of the back contact battery.

[0165] In practical applications, the regular distribution of island-shaped passivation structures in back-contact batteries can be determined based on the light-trapping requirements of different areas on the back side of the battery; no specific limitations are made here. For example... Figure 19 and Figure 20As shown, different island-shaped passivation structures 14 disposed on the side of the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 away from the semiconductor substrate 11 may be regularly distributed; different island-shaped passivation structures 14 disposed between the first doped semiconductor layer 12 and / or the second doped semiconductor layer 13 and the semiconductor substrate 11 may be regularly distributed; or all island-shaped passivation structures 14 included in the back contact battery may be regularly distributed.

[0166] At least some island passivation structures exhibit a regular distribution, meaning that the different island passivation structures within this portion are distributed in a predictable pattern. For example, different island passivation structures may be distributed along a fixed direction (e.g., in a matrix or concentric circles). Another example is that different island passivation structures are distributed with approximately the same spacing. Yet another example is that different island passivation structures exhibit approximately the same pattern morphology.

[0167] In terms of formation location, the island-shaped passivation structure included in the back contact battery can be disposed only on the side of the first doped semiconductor layer away from the semiconductor substrate, only on the side of the second doped semiconductor layer away from the semiconductor substrate, only between the first doped semiconductor layer and the semiconductor substrate, only between the second doped semiconductor layer and the semiconductor substrate, or a combination of at least two of the above four cases. This application does not specifically limit the formation location of the island-shaped passivation structure; it can be determined according to the actual application scenario and the actual manufacturing process.

[0168] For example, such as Figure 17 As shown, the island passivation structure 14 disposed on the first region 15 can be located on the side of the first doped semiconductor layer 12 away from the semiconductor substrate 11, and the island passivation structure 14 disposed on the second region 16 can be disposed between the second doped semiconductor layer 13 and the semiconductor substrate 11.

[0169] Or, such as Figure 22 As shown, the island passivation structure 14 disposed on the first region 15 is located between the first doped semiconductor layer 12 and the semiconductor substrate 11, and the island passivation structure 14 disposed on the second region 16 is disposed on the side of the second doped semiconductor layer 13 away from the semiconductor substrate 11.

[0170] It is worth noting that the first doped semiconductor layer and the second doped semiconductor layer of the back contact battery are formed on local areas of the first surface in different operation steps. Furthermore, the patterned first and second doped semiconductor layers are obtained by selectively etching the entire layer of doped semiconductor layers during fabrication. Therefore, taking as an example an island-shaped passivation structure located on the side of the first doped semiconductor layer away from the semiconductor substrate in the first region, and an island-shaped passivation structure located between the second doped semiconductor layer and the semiconductor substrate in the second region: In this case, the first doped semiconductor layer can be fabricated first, and the island-shaped passivation structure located between the second doped semiconductor layer and the semiconductor substrate can be fabricated based on the portion of the doped semiconductor material of the first doped semiconductor layer located in the second region. Simultaneously, after forming the first doped semiconductor layer and the island-shaped passivation structure in the second region, the second doped semiconductor layer can be fabricated, and the island-shaped passivation structure located on the side of the first doped semiconductor layer away from the semiconductor substrate can be fabricated based on the portion of the doped semiconductor material of the second doped semiconductor layer located in the first region. This improves the manufacturing efficiency of the back contact battery and simplifies the manufacturing process.

[0171] Secondly, embodiments of this application provide a photovoltaic module, which includes: a battery string and an encapsulation layer. The battery string is formed by the electrical connection of multiple back-contact batteries provided in the first aspect and its various implementations; the encapsulation layer covers the surface of the battery string.

[0172] 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.

[0173] Unless there are technical obstacles or contradictions, the various technical features disclosed in this application can be freely combined to form other embodiments, all of which are within the protection scope of this application.

[0174] 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.

[0175] 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, and island passivation structure; The semiconductor substrate has a first side and a second side opposite to each other; The first surface includes an alternating first region and a second region, as well as an interval region located between the first region and the second region; Along the direction from the first surface to the second surface, the surface of the spacer region is recessed into the semiconductor substrate relative to the surface of the first region to form a groove structure; the groove structure has a first sidewall near the first region and a second sidewall near the second region; The first doped semiconductor layer is disposed on the first region, and the first doped semiconductor layer has a first boundary close to the spacing region; The second doped semiconductor layer is disposed on the second region, and the second doped semiconductor layer has an opposite conductivity type to the first doped semiconductor layer. The second doped semiconductor layer has a second boundary close to the spacing region. The island-shaped passivation structure is disposed on the semiconductor substrate; wherein at least one of the island-shaped passivation structures is at least partially located between the first boundary and the first sidewall; And / or, at least one of the island-shaped passivation structures is located at least partially between the second boundary and the second sidewall.

2. The back contact battery according to claim 1, characterized in that, The first boundary has a first sub-boundary located within the first region and spaced apart from the first sidewall along the width direction of the interval region, and at least one of the first sub-boundaries and the first sidewall is provided with the island-shaped passivation structure; And / or, the second boundary has a second sub-boundary located within the second region and spaced apart from the second sidewall along the width direction of the interval region, and at least one of the second sub-boundaries and the second sidewall is provided with the island-shaped passivation structure.

3. The back contact battery according to claim 1, characterized in that, The portion of the first region that is close to the first sidewall and is not directly covered by the first doped semiconductor layer is a plateau region, and / or the portion of the second region that is close to the second sidewall and is not directly covered by the second doped semiconductor layer is a plateau region; The platform region includes a plane that is substantially parallel to the first surface; at least one of the island-shaped passivation structures is disposed on the plane included in the platform region.

4. The back contact battery according to claim 3, characterized in that, Along the width direction of the interval region, the width of the plane included in at least one of the platform regions is less than or equal to 1 μm.

5. The back contact battery according to claim 3, characterized in that, In the case where the first region has the platform area, at least one of the platform areas further includes a third sidewall that is remote from the first sidewall and continuous with the plane; and / or, in the case where the second region has the platform area, at least one of the platform areas further includes a third sidewall that is remote from the second sidewall and continuous with the plane. The third sidewall is either perpendicular to the plane or inclined to the plane.

6. The back contact battery according to claim 5, characterized in that, At least one of the island-shaped passivation structures further extends from the plane to at least a portion of the third sidewall; And / or, along the thickness direction of the semiconductor substrate, the height of the third sidewall is greater than or equal to 0.05 μm and less than or equal to 8 μm.

7. The back contact battery according to claim 5, characterized in that, In the case where the first region has the platform region, a portion of the first boundary also extends above the plane included in the platform region, and the first doped semiconductor layer and the island passivation structure are distributed at intervals; And / or, in the case where the second region has the platform region, a portion of the second boundary also extends above the plane included in the platform region, with the second doped semiconductor layer and the island passivation structure spaced apart.

8. The back contact battery according to claim 7, characterized in that, Where part of the first boundary also extends above the plane included in the platform region, the spacing between the first doped semiconductor layer and the island passivation structure is greater than or equal to 1 nm and less than or equal to 500 nm along the thickness direction of the semiconductor substrate. And / or, where a portion of the second boundary also extends above the plane included in the platform region, the spacing between the second doped semiconductor layer and the island passivation structure is greater than or equal to 1 nm and less than or equal to 500 nm along the thickness direction of the semiconductor substrate.

9. The back contact battery according to claim 7, characterized in that, Where a portion of the first boundary extends above the plane included in the platform area, the extension width of the first boundary relative to the third sidewall is less than or equal to 1 μm along the width direction of the interval region; And / or, where a portion of the second boundary also extends above the plane included in the platform region, the extension width of the second boundary relative to the third sidewall is less than or equal to 1 μm along the width direction of the interval region.

10. The back contact battery according to claim 3, characterized in that, At least one of the island-shaped passivation structures accounts for more than 50% of the area within the platform region.

11. The back contact battery according to claim 2, characterized in that, The first boundary has a first concave-convex alternating structure, and the boundary of at least a portion of the concave portion in the first concave-convex alternating structure is the first sub-boundary. And / or, the second boundary has a second concave-convex alternating structure, and the boundary of at least a portion of the concave portion in the second concave-convex alternating structure is the second sub-boundary.

12. The back contact battery according to claim 11, characterized in that, At least a portion of the protrusions in the first alternating concave-convex structure and / or the second alternating concave-convex structure extend over the groove structure along the width direction of the interval region.

13. The back contact battery according to claim 12, characterized in that, In the first alternating concave-convex structure, at least one of the protrusions extends with a width of less than or equal to 1 μm over the groove structure relative to the first sidewall; And / or, at least one of the protrusions in the second alternating concave-convex structure extends over the groove structure with a width of less than or equal to 1 μm relative to the second sidewall.

14. The back contact battery according to claim 11, characterized in that, Along the extending direction of the interval region, the first sidewall has a third alternating concave-convex structure, wherein at least some of the protrusions in the third alternating concave-convex structure are staggered with the adjacent protrusions in the first alternating concave-convex structure; And / or, along the extension direction of the interval region, the second sidewall has a fourth alternating concave-convex structure, wherein at least some of the protrusions in the fourth alternating concave-convex structure are staggered with the adjacent protrusions in the second alternating concave-convex structure.

15. The back contact battery according to claim 1, characterized in that, At least one of the island-shaped passivation structures includes a doped semiconductor passivation portion; And / or, at least one of the island-shaped passivation structures includes an interface passivation portion; And / or, at least one of the island passivation structures includes a doped semiconductor portion and a doped silicon glass portion disposed on the side of the doped semiconductor portion facing away from the semiconductor substrate.

16. The back contact battery according to claim 15, characterized in that, In at least one of the island-shaped passivation structures disposed between the first boundary and the first sidewall, the material and conductivity type of the doped semiconductor portion are the same as those of the second doped semiconductor layer; And / or, in at least one of the island-shaped passivation structures disposed between the second boundary and the second sidewall, the material and conductivity type of the doped semiconductor portion are the same as those of the first doped semiconductor layer.

17. The back contact battery according to claim 15, characterized in that, 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; In at least one of the island-shaped passivation structures disposed between the first boundary and the first sidewall, the material of the interface passivation portion is the same as the material of the second interface passivation layer. And / or, in at least one of the island-shaped passivation structures disposed between the second boundary and the second sidewall, the material of the interface passivation portion is the same as the material of the first interface passivation layer.

18. The back contact battery according to claim 15, characterized in that, The back contact battery further includes a first doped silicon glass layer disposed on the side of the first doped semiconductor layer away from the semiconductor substrate, and a second doped silicon glass layer disposed on the side of the second doped semiconductor layer away from the semiconductor substrate; The first doped silicon glass layer and the first doped semiconductor layer have the same conductivity type; the second doped silicon glass layer and the second doped semiconductor layer have the same conductivity type. In at least one of the island-shaped passivation structures disposed between the first boundary and the first sidewall, the material and conductivity type of the doped silicon glass portion are the same as those of the second doped silicon glass layer. And / or, in at least one of the island-shaped passivation structures disposed between the second boundary and the second sidewall, the material and conductivity type of the doped silicon glass portion are the same as those of the first doped silicon glass layer.

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

Images