Back contact battery and photovoltaic module

Abstract

The invention discloses a back contact cell and a photovoltaic module, relates to the technical field of photovoltaic, and is used for reducing the risk of electric leakage between a first doped semiconductor layer and a second doped semiconductor layer. The back contact battery comprises a semiconductor substrate, a first doped semiconductor layer and a second doped semiconductor layer. In the direction from the first face to the second face, the surface of the interval area is recessed inwards relative to the surface of the first area, so that a groove structure is formed. The first doped semiconductor layer is at least partially disposed on the first region. The second doped semiconductor layer is disposed on the second region. The conductive types of the second doped semiconductor layer and the first doped semiconductor layer are opposite. Wherein the first doped semiconductor layer comprises a first boundary close to the spacer region in the extending direction of the spacer region. In the width direction of the spacer region, the first boundary comprises a first sub-boundary located in the first region and a second sub-boundary which extends from the first region to the position above the groove structure and is located above the groove structure.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic technology, and in particular, to a back-contact battery and a photovoltaic module. Background Art

[0002] A back-contact battery refers to a solar cell in which the light-facing surface of the cell has no electrodes, and the positive and negative electrodes are both disposed on the backlight side of the cell, thereby reducing the shielding of the electrodes on the cell and increasing the short-circuit current of the cell, and improving the energy conversion efficiency of the cell.

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

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

[0005] To achieve the above object, in a first aspect, the present invention provides a back-contact battery, which includes: a semiconductor substrate, a first doped semiconductor layer, and a second doped semiconductor layer. The semiconductor substrate includes opposite first and second surfaces. The first surface includes alternately and spaced-apart first and second regions, and a spacer region located between the first and second regions. Along the direction from the first surface to the second surface, the surface of the spacer region is recessed inward relative to the surface of the first region to form a groove structure. The first doped semiconductor layer is at least partially disposed on the first region. The second doped semiconductor layer is disposed on the second region. The second doped semiconductor layer and the first doped semiconductor layer have opposite conduction types. Wherein, along the extending direction of the spacer region, the first doped semiconductor layer includes a first boundary close to the spacer region. Along the width direction of the spacer region, the first boundary includes a first sub-boundary located in the first region, and a second sub-boundary extending from the first region to above the groove structure and located above the groove structure.

[0006] In the case of adopting the above technical solution, when the back contact battery is in a working state, the first doped semiconductor layer and the second doped semiconductor layer can effectively shunt and collect carriers, which is conducive to the formation of photocurrent. Secondly, the spacer region provided between the first region and the second region can separate the first doped semiconductor layer and the second doped semiconductor layer, reducing the leakage risk between them. And, along the width direction of the spacer region, the first boundary of the first doped semiconductor layer not only includes a second sub-boundary extending from the first region above the groove structure. At this time, the part of the first doped semiconductor layer corresponding to the second sub-boundary is suspended above the groove structure, which is conducive to reflecting part of the light emitted from the first surface of the semiconductor substrate back to the semiconductor substrate and being utilized by the semiconductor substrate again, improving the light utilization rate of the back contact battery. In addition, the first boundary of the first doped semiconductor layer further includes a first sub-boundary located in the first region and far from the groove structure. At this time, the part of the first doped semiconductor layer corresponding to the first sub-boundary indents into the first region relative to the first sidewall of the groove structure (the sidewall of the groove structure close to the first region), which can increase the distance between part of the first doped semiconductor layer and the second doped semiconductor layer, reducing the leakage risk between them. Compared with the back contact battery in the prior art where each part of the first boundary is suspended above the groove structure, the back contact battery provided by the present invention has a lower leakage risk and carrier recombination rate. And compared with the case where each part of the first boundary indents into the first region, the back contact battery provided by the present invention has a higher light utilization rate and can improve the working performance of the back contact battery.

[0007] As a possible implementation, along the extending direction of the spacer region, within a unit length, the total length of the first sub-boundary located in the first region is greater than the total length of the second sub-boundary located above the groove structure.

[0008] In the case of adopting the above technical solution, it can be understood that the distance between the part of the first doped semiconductor layer corresponding to the first sub-boundary and the second doped semiconductor layer is greater than that between the part of the first doped semiconductor layer corresponding to the second sub-boundary and the second doped semiconductor layer. Based on this, when within a unit length, the total length of the first sub-boundary located in the first region is greater than the total length of the second sub-boundary located above the groove structure, the proportion of the part of the first boundary of the first doped semiconductor layer with a larger distance from the second doped semiconductor layer is higher, which is conducive to further reducing the leakage risk between the first doped semiconductor layer and the second doped semiconductor layer and reducing the carrier recombination rate of the back contact battery.

[0009] As a possible implementation, the first boundary of the first doped semiconductor layer close to the spacer region has an alternating concave and convex structure, and the alternating concave and convex structure includes a concave boundary and a convex boundary.

[0010] As a possible implementation solution, the first sub-boundary includes at least a part of the concave boundary, and the second sub-boundary includes at least a part of the convex boundary. In this case, the first doped semiconductor layer is disposed opposite to at least a part of the concave boundary in the concave-convex alternating structure at the first sub-boundary within the first region, and the first doped semiconductor layer is disposed opposite to at least a part of the convex boundary in the concave-convex alternating structure at the second sub-boundary above the groove structure, which is beneficial to making the concave-convex alternating structure presented by the first boundary more matched with the undulating changes of the part where the first doped semiconductor layer indents into the first region and the part where the first doped semiconductor layer extends overhangingly onto the groove structure, and can reduce the etching amount of the semiconductor substrate for making the first boundary of the first doped semiconductor layer have both the first sub-boundary and the second sub-boundary, which is beneficial to increasing the light absorption area of the semiconductor substrate and improving the conversion efficiency of the back contact battery.

[0011] As a possible implementation solution, the first sub-boundary includes at least a part of the concave boundary and at least a part of the convex boundary; or, the second sub-boundary includes at least a part of the concave boundary and at least a part of the convex boundary. This is beneficial to reducing the manufacturing process difficulty of the back contact battery and improving the yield rate of the back contact battery.

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

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

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

[0015] In the case of adopting the above technical solution, the extending width W2 of the first sub-boundary within the first region is within the above range, which is beneficial to preventing the area ratio of the first doped semiconductor layer on the first region from being too small due to the too large extending width W2 of the first sub-boundary within the first region, and is beneficial to making the first doped semiconductor layer have a high field passivation effect and carrier collection ability, and further improving the working performance of the back contact battery.

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

[0017] In the case of adopting the above technical solution, the extension width W3 of the second sub-boundary above the groove structure is within the above range, which is conducive to preventing the minimum distance between the first doped semiconductor layer and the second doped semiconductor layer from being too small due to the excessive extension width W3 of the second sub-boundary above the groove structure, and further reducing the leakage risk between the back contact cells.

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

[0019] In the case of adopting the above technical solution, the first platform region includes a platform surface substantially perpendicular to the thickness direction of the semiconductor substrate. At this time, the surface of the portion in the first region of the semiconductor substrate that is not directly covered by the first doped semiconductor layer (i.e., the first platform region) is relatively flat, which is conducive to reducing the number of surface defects in the first platform region and reducing the carrier recombination rate. Moreover, the platform surface has a high light reflection effect, which is conducive to reducing the probability of light in the semiconductor substrate exiting from the first platform region and improving the light utilization rate of the back contact cell.

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

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

[0022] As a possible implementation, a part of the sidewall of the first doped semiconductor layer is aligned with the second sidewall of at least one adjacent first platform region; or, at least one first sub-boundary located in the first region extends above the platform surface.

[0023] In the case of adopting the above technical solution, when a part of the side wall of the first doped semiconductor layer is aligned with the second side wall of at least one adjacent first platform region, the distance between this part of the side wall of the first doped semiconductor layer and the second doped semiconductor layer is relatively large, which is beneficial to further reducing the leakage risk between the two. When at least one first sub-boundary in the first region extends above the platform surface, although the distance between this part of the first boundary and the second doped semiconductor layer is relatively small, the part of the first doped semiconductor layer corresponding to this part of the first boundary can reflect part of the light emitted from the platform surface, so that part of the light can re-enter the semiconductor substrate, further improving the light utilization rate of the back contact battery.

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

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

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

[0027] In the case of adopting the above technical solution, when the height of the second side wall is within the above range, it is beneficial to prevent the large change in height between the bottom surface of the groove structure and the surface of the region with a larger height in the first region due to the small height of the second side wall, which is beneficial to further improving the passivation effect of the surface passivation layer at the junction of the first region and the spacer region. In addition, it can also prevent the large etching amount of the part of the semiconductor substrate corresponding to the first platform region due to the large height of the second side wall, which is beneficial to making the part of the semiconductor substrate corresponding to the first platform region have a large light absorption depth, beneficial to improving the light utilization rate of the semiconductor substrate, and further improving the conversion efficiency of the back contact battery.

[0028] As a possible implementation solution, the back contact battery further includes an island-shaped passivation structure disposed on the first platform region, and the island-shaped passivation structure is spaced apart from the first doped semiconductor layer.

[0029] In the case of adopting the above technical solution, the island-shaped passivation structure has a passivation function, which can passivate the surface of the region of the semiconductor substrate with the island-shaped passivation structure, reduce the number of defects on the region surface, and reduce the carrier recombination rate. In addition, there is a height difference between the surface of the island-shaped passivation structure and the first platform region, so that the side surface and / or top surface of the island-shaped passivation structure can reflect the 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 to more incident light refracting into the battery, improving the absorption ratio of the incident light, and improving the bifaciality of the back-contact battery.

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

[0031] In the case of adopting the above technical solution, the island-shaped passivation structure can be formed by at least two passivation parts, namely a doped semiconductor passivation part and an interface passivation part, which have good effects and are compatible with the battery manufacturing process. While making the island-shaped passivation structure have a good passivation effect, it can also improve the yield of the back-contact battery. In addition, the doped semiconductor passivation part and the interface passivation part are also materials for manufacturing the back-contact battery. At this time, the manufacturing of the island-shaped passivation structure can be realized while manufacturing the corresponding structures in the back-contact battery, improving the manufacturing efficiency of the back-contact battery and simplifying the manufacturing process of the back-contact battery.

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

[0033] In the case of adopting the above technical solution, taking the example that the material and conductivity type of the doped semiconductor passivation part included in the island-shaped passivation structure are the same as those of the second doped semiconductor layer respectively: the manufacturing of the island-shaped passivation structure can be realized while manufacturing the second doped semiconductor layer, improving the manufacturing efficiency of the back-contact battery and simplifying the manufacturing process of the back-contact battery.

[0034] As a possible implementation solution, the back-contact battery further includes a first interface passivation layer disposed between the semiconductor substrate and the first doped semiconductor layer, and a second interface passivation layer disposed between the semiconductor substrate and the second doped semiconductor layer. The material of the interface passivation part is the same as that of the first interface passivation layer or the second interface passivation layer. The application principle of the beneficial effects in this case can refer to the application principle of the beneficial effects that the material and conductivity type of the doped semiconductor passivation part are the same as those of one of the first doped semiconductor layer and the second doped semiconductor layer respectively, which will not be elaborated here.

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

[0036] In a second aspect, the present invention provides a photovoltaic module, which includes the back contact battery provided by the first aspect and its various implementation manners.

[0037] For the beneficial effects of the second aspect and its various implementation manners of the present invention, reference can be made to the analysis of the beneficial effects in the first aspect and its various implementation manners, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0039] Figure 1 is a longitudinal sectional schematic view of the first structure of the back contact battery provided by the embodiment of the present invention;

[0040] Figure 2 is a longitudinal sectional schematic view of the second structure of the back contact battery provided by the embodiment of the present invention;

[0041] Figure 3 is a partial structure SEM diagram of the back contact battery provided by the embodiment of the present invention at the first boundary of the first doped semiconductor layer close to the first region (the direction of the bold arrow in the figure is the extension direction of the spacer region);

[0042] Figure 4 The (1), (2), and (3) parts in are top view structure schematic diagrams of the back contact battery provided by the embodiment of the present invention at a partial spacer region (the dotted line in the figure shows the morphology of the first sidewall, and the direction of the bold arrow in the figure is the extension direction of the spacer region);

[0043] Figure 5 is a longitudinal sectional schematic view of the third structure of the back contact battery provided by the embodiment of the present invention;

[0044] Figure 6 is a longitudinal sectional schematic view of the fourth structure of the back contact battery provided by the embodiment of the present invention;

[0045] Figure 7 is a longitudinal sectional schematic view of the fifth structure of the back contact battery provided by the embodiment of the present invention;

[0046] Figure 8 is a longitudinal sectional schematic view of the sixth structure of the back contact battery provided by the embodiment of the present invention;

[0047] Figure 9Schematic longitudinal sectional view of the seventh structure of the back-contact battery provided by the embodiment of the present invention;

[0048] Figure 10 Schematic longitudinal sectional view of the eighth structure of the back-contact battery provided by the embodiment of the present invention;

[0049] Figure 11 Schematic longitudinal sectional view of the ninth structure of the back-contact battery provided by the embodiment of the present invention;

[0050] Figure 12 Schematic longitudinal sectional view of the tenth structure of the back-contact battery provided by the embodiment of the present invention;

[0051] Figure 13 Schematic longitudinal sectional view of the eleventh structure of the back-contact battery provided by the embodiment of the present invention;

[0052] Figure 14 Schematic longitudinal sectional view of the twelfth structure of the back-contact battery provided by the embodiment of the present invention.

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

[0054] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0055] Various structural schematic diagrams according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, where in order to express more clearly, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0056] In the context of the present invention, when a layer / component is referred to as being "on" another layer / component, the layer / component may be directly on the other layer / component, or there may be an intermediate layer / component therebetween. Additionally, if a layer / component is "on" another layer / component in one orientation, then when the orientation is reversed, the layer / component may be "under" the other layer / component. In order to make the technical problems to be solved, the technical solutions and the beneficial effects of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0057] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "a plurality" is two or more, unless otherwise specifically defined. The meaning of "several" is one or more, unless otherwise specifically defined.

[0058] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] A solar cell is a device that can convert the light energy of the sun into electrical energy. Specifically, when the solar cell is in a working state, sunlight shines on the semiconductor p-n junction of the solar cell, forming new hole-electron pairs. Under the action of the built-in electric field in the p-n junction, the photo-generated holes flow to the p region, and the photo-generated electrons flow to the n region. After connecting the circuit, an electric current can be generated. Among them, a solar cell in which both the positive electrode and the negative electrode are on the back surface of the battery is a back-contact cell. Compared with a double-sided contact solar cell, the front surface of the back-contact cell has no metal electrode obstruction, so that the light-facing side of the back-contact cell has a higher light utilization rate. Therefore, the back-contact cell has a higher short-circuit current and a higher photoelectric conversion efficiency, and is one of the technical directions for realizing high-efficiency crystalline silicon cells at present.

[0060] Specifically, a back-contact battery generally includes a semiconductor substrate, and a first doped semiconductor layer and a second doped semiconductor layer that are alternately and spaced apart on the same surface of the semiconductor substrate. The first doped semiconductor layer and the second doped semiconductor layer have opposite conductivity types to achieve the shunting and collection of carriers. Among them, in order to reduce the leakage risk between the first doped semiconductor layer and the second doped semiconductor layer, a groove structure is often provided in the interval region between the two to ensure that there is no residue in the interval region after patterning the first doped semiconductor layer and the second doped semiconductor layer.

[0061] However, in the actual manufacturing process, due to the existence of the mask structure and the side etching of the etchant for etching the groove structure during the etching of the semiconductor substrate, the end regions of the first doped semiconductor layer close to the interval region are suspended above the groove structure. Although the suspended end is beneficial to reflecting part of the light emitted from the first surface back to the semiconductor substrate, since the suspended end is far from the substrate, it cannot directly and effectively collect the photo-generated carriers generated by the substrate, but instead acts as a transmission loss, affecting the fill factor. At the same time, the suspended end causes the distance between the first doped semiconductor layer and the second doped semiconductor layer to be small, thereby increasing the leakage risk between the first doped semiconductor layer and the second doped semiconductor layer with opposite conductivity types.

[0062] To solve the above technical problems, in a first aspect, an embodiment of the present invention provides a back-contact battery. As Figures 1 to 4 shown, the back-contact battery includes: a semiconductor substrate 11, a first doped semiconductor layer 12, and a second doped semiconductor layer 13. The semiconductor substrate 11 includes opposite first and second surfaces. The first surface includes alternately and spaced-apart first regions 14 and second regions 15, and an interval region 16 located between the first region 14 and the second region 15. Along the direction from the first surface to the second surface, the surface of the interval region 16 is recessed inward relative to the surface of the first region 14 to form a groove structure 17. The first doped semiconductor layer 12 is at least partially disposed on the first region 14. The second doped semiconductor layer 13 is disposed on the second region 15. The second doped semiconductor layer 13 and the first doped semiconductor layer 12 have opposite conductivity types. Among them, along the extension direction of the interval region 16, the first doped semiconductor layer 12 includes a first boundary close to the interval region 16. Along the width direction of the interval region 16, the first boundary includes a first sub-boundary 18 located in the first region 14, and a second sub-boundary 19 that extends from the first region 14 above the groove structure 17 and is located above the groove structure 17.

[0063] In the case of adopting the above technical solution, when the back-contact battery is in a working state, the first doped semiconductor layer and the second doped semiconductor layer can effectively shunt and collect carriers, which is beneficial to the formation of a photocurrent. Secondly, asFigures 1 to 4 , and Figure 8 As shown in Figure 8 , the spacer region 16 disposed between the first region 14 and the second region 15 can separate the first doped semiconductor layer 12 and the second doped semiconductor layer 13, reducing the risk of leakage current between the two. Moreover, along the width direction of the spacer region 16, the first boundary of the first doped semiconductor layer 12 not only includes the second sub-boundary 19 extending from the first region 14 above the groove structure 17. At this time, the portion of the first doped semiconductor layer 12 corresponding to the second sub-boundary 19 is suspended above the groove structure 17, which is beneficial to reflecting part of the light emitted from the first surface of the semiconductor substrate 11 back to the semiconductor substrate 11 and being utilized by the semiconductor substrate 11 again, improving the light utilization rate of the back contact battery. In addition, the first boundary of the first doped semiconductor layer 12 further includes the first sub-boundary 18 located in the first region 14 and away from the groove structure 17. At this time, the portion of the first doped semiconductor layer 12 corresponding to the first sub-boundary 18 is indented into the first region 14 relative to the first sidewall 22 of the groove structure 17 (the sidewall of the groove structure 17 close to the first region 14. In addition, the groove structure 17 also has a third sidewall 23 close to the second region 15. The boundaries of the first sidewall 22 and / or the third sidewall 23 can be linear, curved, or polygonal, etc. The specific morphologies of the two can be determined according to the actual manufacturing process and are not specifically limited here), which can increase the distance between part of the first doped semiconductor layer 12 and the second doped semiconductor layer 13, reduce the risk of leakage current between the two, and can improve the fill factor of the solar cell. Compared with the back contact battery in the prior art where all parts of the first boundary are suspended above the groove structure 17, the back contact battery provided by the embodiment of the present invention has a lower risk of leakage current and carrier recombination rate and a higher fill factor. And compared with the case where all parts of the first boundary are indented into the first region 14, the back contact battery provided by the embodiment of the present invention has a higher light utilization rate and can improve the working performance of the back contact battery.

[0064] In the actual application process, the embodiment of the present invention does not specifically limit the material and conductivity type of the semiconductor substrate. Exemplarily, the semiconductor substrate can be a silicon substrate. Alternatively, the semiconductor substrate can also be a substrate of any semiconductor material such as a germanium-silicon substrate, a germanium substrate, or a gallium arsenide substrate. Secondly, the semiconductor substrate can be an N-type semiconductor substrate, a P-type semiconductor substrate, or an intrinsic semiconductor substrate.

[0065] Secondly, the semiconductor substrate includes opposite first and second surfaces. The first surface of the semiconductor substrate corresponds to the back surface of the back-contact battery, and the second surface of the semiconductor substrate corresponds to the front surface of the back-contact battery. Among them, the distribution of the first region, the second region, and the spacer region on the first surface can be determined according to the distribution of the first doped semiconductor layer and the second doped semiconductor layer formed on the first surface. Specifically, since at least part of the first doped semiconductor layer included in the back-contact battery is disposed on the first region, the distribution range of the first region on the first surface can be determined according to the distribution requirements of the first doped semiconductor layer in the actual application scenario and the anti-leakage requirements between the first doped semiconductor layer and the second doped semiconductor layer. Since the second doped semiconductor layer included in 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 according to 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 region and the second region are confirmed, the distribution range of the spacer region on the first surface is determined.

[0066] It can be understood that one of the first region and the second region roughly corresponds to the emitter region, and the other roughly corresponds to the back field region. In terms of the specific conduction type, one of the first region and the second region roughly corresponds to the P region, and the other roughly corresponds to the N region.

[0067] As for the shapes of the first region and the second region, they can be set according to actual needs as long as they can be applied to the back-contact battery provided in the embodiments of the present invention. For example: the first region and the second region can be alternately distributed in a strip shape, or can be alternately distributed in an interdigitated shape.

[0068] In terms of the surface topography, as Figure 1 and Figure 2 shown, the second surface of the semiconductor substrate 11 can be a polished surface. Or, as Figure 5 shown, the second surface of the semiconductor substrate 11 can also be a textured surface to improve the light trapping effect of the second surface and improve the light utilization rate of the semiconductor substrate 11.

[0069] As for the topography of the first surface of the semiconductor substrate, the first surface can be a flat surface to facilitate improving the formation quality of the first doped semiconductor layer and the second doped semiconductor layer on the first surface and improving the field passivation effect of the two.

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

[0071] In terms of the 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 in the spacer region can be set according to actual requirements and will not be specifically limited here.

[0072] As for the surface of the second region, the surface of the second region can be flush with the surface of the first region; or, as Figure 6 shown, along the direction from the first surface to the second surface, the surface of the second region 15 can also be recessed into the semiconductor substrate 11 relative to the surface of the first region 14 to prevent residues remaining on the second region 15 after patterning the first doped semiconductor layer 12 and reduce the risk of leakage. In this case, the surface of the second region can be flush with the surface of the spacer region; or, as Figure 6 shown, the surface of the second region 15 can also be higher than the bottom surface of the groove of the spacer region 16. As for the depth of the recess of the surface of the second region 15 into the semiconductor substrate 11, it can be set according to actual requirements and will not be specifically limited here.

[0073] For the first doped semiconductor layer and the second doped semiconductor layer, in terms of the conduction type, the embodiments of the present invention do not specifically limit the conduction types of the first doped semiconductor layer and the second doped semiconductor layer, as long as the conduction types of the first doped semiconductor layer and the second doped semiconductor layer are opposite. Specifically, the conduction type of the first doped semiconductor layer can be N-type, and the conduction type of the second doped semiconductor layer is P-type. Or, the conduction type of the first doped semiconductor layer can also be P-type, and the conduction type of the second doped semiconductor layer is N-type.

[0074] Optionally, the first doped semiconductor layer is a P-type doped semiconductor layer; and / or, the first doped semiconductor layer is an emitter doped layer. In this case, a film layer with strong corrosion resistance such as a borosilicate glass layer can be used to play a protective role during the patterning process of the first doped semiconductor layer, which is beneficial to making the first boundary of the first doped semiconductor layer have both the above-mentioned first sub-boundary and second sub-boundary and reducing the manufacturing process difficulty.

[0075] In terms of materials, the materials of the first doped semiconductor layer and / or the second doped semiconductor layer can include any semiconductor material such as silicon, silicon-germanium, germanium, or gallium arsenide. In terms of the arrangement form of substances, the crystal phases of the first doped semiconductor layer and / or the second doped semiconductor layer can be amorphous, microcrystalline, nanocrystalline, single crystal, or polycrystalline, etc.

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

[0077] In terms of the formation position, as Figure 6 shown, at least part of the first doped semiconductor layer 12 can be directly disposed on the first region 14. Or, as Figure 7 shown, the back contact battery can 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 passivation 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 carriers, reduce the carrier recombination rate of the first region 14 on the first surface of the semiconductor substrate 11, and further improve the photoelectric conversion efficiency of the back contact battery. The material and thickness of the first interface passivation layer 28 can be set according to the material of the first doped semiconductor layer 12 and actual requirements, and are not specifically limited here. For example: when the material of the first doped semiconductor layer is doped polysilicon, the first interface passivation layer is a tunneling passivation layer. Another example: when the material of the first doped semiconductor layer includes at least one of doped amorphous silicon, doped microcrystalline silicon and doped nanocrystalline silicon, the first interface passivation layer is an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, an intrinsic nanocrystalline silicon layer or a mixed layer of the above three.

[0078] As for the second doped semiconductor layer, the second doped semiconductor layer can be directly disposed on the second region. Or, as Figure 7 shown, the back contact battery can 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 passivation 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 carriers, reduce the carrier recombination rate of the second region 15 on the first surface of the semiconductor substrate 11, and further improve the photoelectric conversion efficiency of the back contact battery. The principle of setting the material and thickness of the second interface passivation layer 29 can refer to the principle of setting the material and thickness of the first interface passivation layer 28 described above, and will not be elaborated here.

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

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

[0081] Alternatively, along the extension direction of the spacer region, within a unit length, for example, within a 1 cm length, the total length of the first sub-boundary located within the first region can also be equal to the total length of the second sub-boundary located above the groove structure. Or, there is at least one 1 cm unit length in which the total length of the first sub-boundary located within the first region is less than the total length of the second sub-boundary located above the groove structure, so as to reduce the process difficulty of manufacturing the back-contact battery without making the proportion of the portion of the first doped semiconductor layer corresponding to the second sub-boundary too small, which may lead to a too small area proportion of the first doped semiconductor layer within the first region, and is beneficial for the first doped semiconductor layer to have a high field passivation effect and carrier collection ability.

[0082] In addition, during the actual application process, such as Figure 3 and Figure 4As shown, the first boundary of the first doped semiconductor layer 12 adjacent to the spacer region 16 may have an alternating concave and convex structure, which includes a concave boundary 20 and a convex boundary 21. It should be understood that the concave boundary 20 and the convex boundary 21 do not exactly correspond to the first sub-boundary and the second sub-boundary. In the embodiments of the present invention, the corresponding relationships between the concave boundary 20 and the convex boundary 21 included in the alternating concave and convex structure and the first sub-boundary and the second sub-boundary are not specifically limited, and can be determined according to the positional relationship between the first side walls of the groove structure adjacent to the first region in the actual application scenario, as well as the requirements for the leakage risk and light utilization rate of the back contact battery.

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

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

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

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

[0087] Optionally, when the first sub-boundary includes at least part of the concave boundary and the second sub-boundary includes at least part of the convex boundary, the first sub-boundary of the first doped semiconductor layer disposed in the first region is opposite to at least part of the concave boundary in the alternating concave and convex structure, and the second sub-boundary of the first doped semiconductor layer disposed above the groove structure is opposite to at least part of the convex boundary in the alternating concave and convex structure, which is beneficial to making the alternating concave and convex structure presented by the first boundary more matched with the fluctuation changes of the part where the first doped semiconductor layer indents into the first region and the part where the first doped semiconductor layer extends overhanging above the groove structure, and can reduce the etching amount of the semiconductor substrate for making the first boundary of the first doped semiconductor layer have both the first sub-boundary and the second sub-boundary, which is beneficial to increasing the light absorption area of the semiconductor substrate and improving the conversion efficiency of the back contact battery.

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

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

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

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

[0092] Optionally, as Figure 3 and Figure 4 shown, along the width direction of the spacer region 16, the groove structure 17 has a first sidewall 22 close to the first region 14. Along the width direction of the spacer region 16, the first region 14 may further include a first platform region 24 close to the first sidewall 22. Among them, the first platform region 24 may include a platform surface 25 substantially perpendicular to the thickness direction of the semiconductor substrate 11. In this case, the first platform region 24 includes a platform surface 25 substantially perpendicular to the thickness direction of the semiconductor substrate 11. Optionally, that is, the platform surface 25 of the first platform region 24 is relatively flat, for example, it may be a polished surface; at least a part of the first doped semiconductor layer 12 is suspended above the platform surface 25. The flat surface is beneficial to reducing the number of platform surface defects and the carrier recombination rate. Moreover, the platform surface 25 has a high light reflection effect, which is beneficial to reducing the probability of light in the semiconductor substrate 11 exiting from the first platform region 24 and improving the light utilization rate of the back contact battery. It should be noted that when the angle between the platform surface 25 included in the first platform region 24 and the thickness direction of the semiconductor substrate 11 is greater than or equal to 85°, the platform surface 25 can be considered to be substantially perpendicular to the thickness direction of the semiconductor substrate 11.

[0093] Optionally, the platform surface of the first platform region is not perpendicular to the thickness direction of the semiconductor substrate. Optionally, the platform surface may also be an uneven surface with a pyramid-shaped or hole-shaped structure, etc. The topography of the surface included in the first platform region can be set according to actual needs and will not be specifically limited here.

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

[0095] Optionally, as Figures 9 to 14 shown, the first platform region 24 may further include a second sidewall 26 that is away from the first sidewall 22 and continuous with the platform surface 25. The second sidewall 26 is perpendicularly arranged relative to the platform surface 25, or the second sidewall 26 is inclined relative to the platform surface 25. In this case, along the direction from the first surface to the second surface, the platform surface 25 is recessed into the semiconductor substrate 11 relative to the surface of the region directly covered by the first doped semiconductor layer 12 in the first region 14, which can reduce the height change amplitude between the bottom surface of the groove structure 17 and the surface of the region with a larger height in the first region 14, facilitate the formation quality and coating of the surface passivation layer at the junction of the first region 14 and the spacer region 16, reduce the carrier recombination rate at the junction of the first region 14 and the spacer region 16, and at the same time can minimize the transport path of photo-generated carriers on the inclined sidewall and increase the lateral transport path that is more conducive to carrier transport.

[0096] Exemplarily, the width of the first platform region is less than or equal to 10 μm.

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

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

[0099] Of course, according to the size of the back contact battery and the requirements of different actual application scenarios, the height of the second sidewall can also be set to any appropriate value other than 0.05 μm to 8 μm, and no specific limitation is made here. Additionally, the heights of the second sidewalls of different first platform regions can be the same or different.

[0100] Regarding the size of the first platform region, it can be determined according to the formation range of the first doped semiconductor layer on the first region, and no specific limitation is made here. Specifically, the areas of the platform surfaces of different first platform regions can be the same or different.

[0101] In addition, during the actual application process, except for the surface passivation layer, no other structures may be formed on the first platform region included in the back contact battery. Or, in some cases, as Figure 3 and Figure 4 shown, the back contact battery may further include an island-shaped passivation structure 27 disposed on the first platform region 24. In this case, the island-shaped passivation structure 27 has a passivation function, can passivate the surface of the region of the semiconductor substrate 11 where the island-shaped passivation structure 27 is formed, reduce the number of defects on the region surface, and reduce the carrier recombination rate. Additionally, there may be a certain height difference between the island-shaped passivation structure 27 and the surface of the first platform region 24, or there may be a difference in materials between the island-shaped passivation structure 27 and the semiconductor substrate 11, such that the side surface and / or top surface of the island-shaped passivation structure 27 can reflect or refract the incident light on the first surface side 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, improving the incident light absorption ratio, and improving the bifaciality of the back contact battery. Among them, the island-shaped passivation structure 27 can be spaced apart from the first doped semiconductor layer 12, or at least part of the sidewall of the island-shaped passivation structure 27 can be adjacent to the first doped semiconductor layer 12.

[0102] In terms of morphology, at least one island-shaped passivation structure may include a plurality of dot-shaped passivation parts that are not adjacent to each other and are distributed in an aggregated manner. In this case, it is beneficial to increase the specific surface area of a single island-shaped passivation structure, enhance the light trapping effect of the island-shaped passivation structure, and further improve the incident light absorption ratio and the bifaciality of the back-contact battery. In this case, the number of dot-shaped passivation parts included in a single island-shaped passivation structure, as well as the distribution and morphology of different dot-shaped passivation parts, can be set according to actual needs. The dot-shaped passivation part can be in a generally regular morphology such as a quasi-hemispherical shape, a quasi-circular / pyramidal shape, a quasi-circular / frustum shape, a quasi-circular / prismatic shape, or a quasi-mountain peak shape, etc., or it can be an irregular shape with uneven surfaces.

[0103] Or, as Figure 3 and Figure 4 shown, at least one island-shaped passivation structure 27 can also be an integral structure with continuous distribution in different regions of itself. This can provide another example of the morphology of the island-shaped passivation structure, improve the applicability of the back-contact battery provided by the embodiments of the present invention in different application scenarios, and reduce the process difficulty of manufacturing the back-contact battery. In this case, the island-shaped passivation structure 27 can have a relatively flat surface (at this time, the morphology of the island-shaped passivation structure 27 can refer to the morphology of the dot-shaped passivation part with regular shape described above); or, the surface of the island-shaped passivation structure 27 can also have a undulating morphology, and the direction of protrusion or indentation, the position of protrusion or indentation, and the size of protrusion or indentation of the undulating morphology can be set according to actual needs and are not specifically limited here. The application principle of the beneficial effects when at least one island-shaped passivation structure 27 has continuous distribution in different regions and the surface of the island-shaped passivation structure 27 has a undulating morphology can refer to the application principle of the beneficial effects of the island-shaped passivation structure 27 including a plurality of dot-shaped passivation parts that are not adjacent to each other and are distributed in an aggregated manner described above.

[0104] In addition, the edge of at least one island-shaped passivation structure can be in a generally regular shape. For example: when the island-shaped passivation structure is quasi-hemispherical, the edge of the island-shaped passivation structure is quasi-circular. Another example: when the island-shaped passivation structure is quasi-pyramidal, the edge of the island-shaped passivation structure is quasi-polygonal. Or, as Figure 3 and Figure 4 shown, the edge of at least one island-shaped passivation structure 27 is in an irregular shape, which is beneficial to enable the island-shaped passivation structure 27 to have side surfaces arranged in different directions, so that light incident in different directions can be reflected, which is beneficial to more incident light refracting into the battery, and further improves the incident light absorption ratio and the bifaciality of the back-contact battery. In this case, the specific morphology of the irregular-shaped edge of the island-shaped passivation structure 27 can be determined according to the three-dimensional morphology of the island-shaped passivation structure 27 described above and is not specifically limited here.

[0105] It should be noted that when the island-shaped passivation structure includes a plurality of dot-shaped passivation parts that are not adjacent to each other and are distributed in an aggregated manner, the edge of the island-shaped passivation structure refers to the edge of the area occupied by the plurality of dot-shaped passivation parts that are not adjacent to each other and are distributed in an aggregated manner as a whole. When different regions of the island-shaped passivation structure are continuously distributed, the edge of the island-shaped passivation structure refers to the edge surrounded by the continuously distributed different regions.

[0106] In terms of size, the embodiments of the present invention do not specifically limit the size of the island-shaped passivation structure, which can be determined according to the passivation effect requirements for the island-shaped passivation structure in the actual application scenario and the light trapping requirements for the island-shaped passivation structure.

[0107] Exemplarily, 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 100 μm 2 . For example: the area occupied by at least one island-shaped passivation structure can be greater than or equal to 1 μm 2 , 10 μm 2 , 20 μm 2 , 30 μm 2 , 50 μm 2 , 80 μm 2 or 100 μm 2 etc. When the area occupied by at least one island-shaped passivation structure is within the above range, it is beneficial to prevent the passivation effect of the island-shaped passivation structure from being too low due to the too small area occupied by the island-shaped passivation structure, and the degree of the light trapping effect of the island-shaped passivation structure itself or enhanced by the setting of the island-shaped passivation structure, which is conducive to making the back contact battery have a high bifaciality. In addition, it can also prevent 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 previous text and will not be elaborated here).

[0108] Exemplarily, 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 example: the longest side dimension of at least one island-shaped passivation structure can be 0.5 μm, 1 μm, 2 μm, 3 μm, 5 μm, 6 μm, 8 μm or 9 μm, etc.

[0109] Exemplarily, 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 example: the shortest side dimension of at least one island-shaped passivation structure can be 0.05 μm, 0.1 μm, 1 μm, 2 μm, 3 μm, 5 μm, 6 μm, 6.5 μm, 7 μm or 7.5 μm, etc.

[0110] It should be noted that when the island-shaped passivation structure includes a plurality of dot-shaped passivation parts that are not adjacent to each other and are distributed in an aggregated manner, the area occupied by the island-shaped passivation structure refers to the area of the region occupied by the plurality of dot-shaped passivation parts that are not adjacent to each other and are distributed in an aggregated manner as a whole. When different regions of the island-shaped passivation structure are continuously distributed, the area occupied by the island-shaped passivation structure refers to the area enclosed by the continuously distributed different regions.

[0111] In terms of structure, the island-shaped passivation structure can be only a single-layer structure or a laminated structure composed of different layers. As for the material of the island-shaped passivation structure, it can be any material with a passivation effect as long as it can be applied to the back-contact battery provided in the embodiments of the present invention.

[0112] Exemplarily, at least one island-shaped passivation structure can include a doped semiconductor passivation part; and / or, at least one island-shaped passivation structure includes an interface passivation part. In this case, the island-shaped passivation structure can be formed at least by the doped semiconductor passivation part and the interface passivation part, which have good effects and are compatible with the battery manufacturing process. While making the island-shaped passivation structure have a good passivation effect, it can also improve the yield of the back-contact battery. In addition, the doped semiconductor passivation part and the interface passivation part are also materials for manufacturing the back-contact battery. At this time, the manufacturing of the island-shaped passivation structure can also be realized while manufacturing the corresponding structures in the back-contact battery, improving the manufacturing efficiency of the back-contact battery and simplifying the manufacturing process of the back-contact battery.

[0113] It should be noted that the island-shaped passivation structure can only include a doped semiconductor passivation part, or only include an interface passivation part, or the island-shaped passivation structure further includes an interface passivation part and a doped semiconductor passivation part (in this case, the doped semiconductor passivation part can be arranged on the side of the interface passivation part away from the semiconductor substrate).

[0114] Among them, the materials and thicknesses of the doped semiconductor passivation part and the interface passivation part included in the island-shaped passivation structure, as well as the conduction type of the doped semiconductor passivation part, can be set according to actual needs and are not specifically limited here.

[0115] Exemplarily, the material and conduction type of the doped semiconductor passivation part can be the same as those of one of the first doped semiconductor layer and the second doped semiconductor layer respectively. In this case, taking the example that the material and conduction type of the doped semiconductor passivation part included in the island-shaped passivation structure are the same as those of the second doped semiconductor layer respectively: the manufacturing of the island-shaped passivation structure can be realized while manufacturing the second doped semiconductor layer, improving the manufacturing efficiency of the back-contact battery and simplifying the manufacturing process of the back-contact battery.

[0116] Exemplarily, the thickness of the doped semiconductor passivation part can be less than or equal to the thickness of one of the first doped semiconductor layer and the second doped semiconductor layer.

[0117] Specifically, regarding the material and conductivity type of the doped semiconductor passivation portion, specifically whether it is the same as the material and conductivity type of the first doped semiconductor layer or the second doped semiconductor layer. Secondly, the size relationship between the thickness of the doped semiconductor passivation portion and the thicknesses of the first doped semiconductor layer and the second doped semiconductor layer can be determined according to the distribution of the island-shaped passivation structure on the first platform region and the relative positional relationship between the island-shaped passivation structure and the first doped semiconductor layer, and no specific limitation is made here.

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

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

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

[0121] Exemplarily, the material of the interface passivation portion is the same as that of the first interface passivation layer or the second interface passivation layer. The application principle of the beneficial effects in this case can refer to the application principle of the beneficial effects where the material and conductivity type of the doped semiconductor passivation portion are the same as those of one of the first doped semiconductor layer and the second doped semiconductor layer described above, and will not be elaborated here.

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

[0123] Specifically, whether the material of the interface passivation part is the same as that of the first interface passivation layer or the second interface passivation layer. Secondly, the size relationship between the thickness of the interface passivation part and the thicknesses of the first interface passivation layer and the second interface passivation layer can be determined according to the distribution of the island-shaped passivation structure on the first platform area and the relative positional relationship between the island-shaped passivation structure and the first doped semiconductor layer. The determination principle of the corresponding relationship between the material, conductivity type, and thickness of the doped semiconductor passivation part and the material, conductivity type, and thickness of the first doped semiconductor layer and the second doped semiconductor layer described above can be referred to, and will not be elaborated here.

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

[0125] When the back-contact battery does not include the first interface passivation layer and / or the second interface passivation layer, the material of the interface passivation part included in the corresponding island-shaped passivation structure can include any one of interface passivation layer materials such as silicon oxide, aluminum oxide, and intrinsic silicon.

[0126] In a second aspect, an embodiment of the present invention provides a photovoltaic module, which includes the back-contact battery provided in the first aspect and its various implementation manners.

[0127] For the beneficial effects of the second aspect and its various implementation manners in the embodiments of the present invention, reference can be made to the analysis of the beneficial effects in the first aspect and its various implementation manners, and will not be elaborated here.

[0128] In the above description, technical details such as the layout and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. with the desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not exactly the same as the methods described above. In addition, although the above embodiments are described separately, this does not mean that the measures in each embodiment cannot be used advantageously in combination.

[0129] The above describes the embodiments of the present invention. However, these embodiments are only for clearer illustration and not for limiting the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present invention.

Claims

1. A back contact battery, characterized in that: include: A semiconductor substrate, wherein the semiconductor substrate comprises a first surface and a second surface opposite to each other; the first surface comprises first regions and second regions alternately spaced and a spacing region between the first regions and the second regions; Along the direction from the first surface to the second surface, the surface of the spacing area is concave inward relative to the surface of the first area to form a groove structure; A first doped semiconductor layer, wherein the first doped semiconductor layer is at least partially disposed on the first region; A second doped semiconductor layer is disposed on the second region; the second doped semiconductor layer and the first doped semiconductor layer have opposite conductivity types; Among them, along the extension direction of the spacing region, the first doped semiconductor layer includes a first boundary close to the spacing region; along the width direction of the spacing region, the first boundary includes a first sub-boundary located in the first region, and a second sub-boundary extending from the first region to above the groove structure and located above the groove structure.

2. The back contact cell according to claim 1, characterized in that: Along the extension direction of the spacing region, within a unit length, the total length of the first sub-boundary located in the first region is greater than the total length of the second sub-boundary located above the groove structure.

3. The back contact cell according to claim 1, characterized in that: The first boundary of the first doped semiconductor layer near the spacing region is in a concave-convex alternating structure, and the concave-convex alternating structure includes a concave boundary and a convex boundary.

4. The back contact cell according to claim 3, characterized in that: The first sub-boundary includes at least a portion of the concave portion boundary, and the second sub-boundary includes at least a portion of the convex portion boundary.

5. The back contact battery according to claim 3, characterized in that: The first sub-boundary includes at least a portion of the concave portion boundary and at least a portion of the convex portion boundary; Alternatively, the second sub-boundary includes at least a portion of the concave portion boundary and at least a portion of the convex portion boundary.

6. The back contact cell according to claim 3, characterized in that: Along the width direction of the spacing region, a distance W1 between the boundaries of adjacent concave portions or a distance W1 between the boundaries of adjacent convex portions is greater than or equal to 1 μm and less than or equal to 15 μm; and / or, along the width direction of the spacing region, an extension width W2 of the first sub-boundary in the first region is less than or equal to 8 μm; And / or, along the width direction of the spacing region, an extension width W3 of the second sub-boundary above the groove structure is less than or equal to 10 μm.

7. The back contact cell according to claim 1, characterized in that: Along the width direction of the spacing region, the groove structure has a first sidewall close to the first region; along the width direction of the spacing region, the first region includes a first platform region close to the first sidewall, and the first platform region includes a platform surface substantially perpendicular to the thickness direction of the semiconductor substrate.

8. The back contact battery according to claim 7, characterized in that: The first platform region further includes a second sidewall that is away from the first sidewall and continuous with the platform surface; The second side wall is vertically disposed relative to the platform surface, or the second side wall is inclined relative to the platform surface.

9. The back contact cell according to claim 8, characterized in that: An included angle between the second side wall and the platform surface is greater than or equal to 30° and less than or equal to 150°.

10. The back contact cell according to claim 7, characterized in that: The back contact cell further includes an island-shaped passivation structure disposed on the first platform region, and the island-shaped passivation structure is spaced apart from the first doped semiconductor layer.

11. The back contact cell according to claim 10, characterized in that: At least one of the island-shaped passivation structures comprises a doped semiconductor passivation portion; And / or, at least one of the island-shaped passivation structures includes an interface passivation portion.

12. The back contact cell according to claim 11, characterized in that: The material and conductivity type of the doped semiconductor passivation portion are respectively the same as the material and conductivity type of one of the first doped semiconductor layer and the second doped semiconductor layer; And / or, the back contact cell further comprises a first interface passivation layer disposed between the semiconductor substrate and the first doped semiconductor layer, and a second interface passivation layer disposed between the semiconductor substrate and the second doped semiconductor layer; The material of the interface passivation portion is the same as that of the first interface passivation layer or the second interface passivation layer.

13. The back contact battery according to any one of claims 1 to 12, characterized in that: The first doped semiconductor layer is a P-type doped semiconductor layer; And / or, the first doped semiconductor layer is an emitter doped layer.

14. A photovoltaic module, characterized in that: Comprising a back contact battery as claimed in any one of claims 1 to 13.

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