Back contact cells and photovoltaic modules

Abstract

The application provides a back contact cell, which comprises a semiconductor substrate, a first doped layer and a second doped layer; a main part of the first doped layer and a main part of the second doped layer are alternately distributed on a back light side of the semiconductor substrate, and the conductive types of the first doped layer and the second doped layer are opposite; a part of the second doped layer is overlapped on a part of the first doped layer to form a laminated structure; wherein one or more pits are formed at the laminated structure. The application also provides a photovoltaic module. The back contact cell of the application forms one or more pits at the laminated structure, so that the light trapping capacity of the back contact cell can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic technology, in particular, to a back contact cell and a photovoltaic module. BACKGROUND

[0002] The back contact cell refers to a solar cell in which no electrode is arranged on the light-receiving surface of the cell, and the positive and negative electrodes are arranged on the back surface of the cell, so that the shading of the cell by the electrodes can be reduced, the short-circuit current of the cell can be increased, and the energy conversion efficiency of the cell can be improved. In actual use, the back contact cell may have bird droppings, leaves, dust and other obstructions falling on the module, which can shield the corresponding position of the cell. After the cell is shielded, the temperature of the cell will rise to generate a hot spot effect. If the temperature generated by the hot spot exceeds a certain temperature value, it will cause problems such as delamination of the photovoltaic module, burning of the back plate, and explosion of the glass, thereby causing the entire solar cell to be scrapped, and in severe cases, it may cause a fire risk. However, the existing back contact cell with a hot spot prevention structure has the problems of excessive leakage loss and excessive local heating.

[0003] Therefore, it is necessary to provide an improved back contact cell and photovoltaic module to overcome or reduce at least some of the above-mentioned drawbacks of the prior art. SUMMARY

[0004] In a first aspect of the present application, a back contact cell is provided, wherein the back contact cell comprises a semiconductor substrate, a first doped layer and a second doped layer.

[0005] The main part of the first doped layer and the main part of the second doped layer are alternately distributed on the back surface side of the semiconductor substrate, and the conductive types of the first doped layer and the second doped layer are opposite.

[0006] A portion of the second doped layer is overlapped above a portion of the first doped layer to form a laminated structure; wherein one or more recesses are formed at the laminated structure.

[0007] In the back contact cell of the present application, a portion of the second doped layer is overlapped above a portion of the first doped layer to form a laminated structure, and one or more recesses are formed at the laminated structure. The one or more recesses can function as light trapping to improve the light trapping capability of the back contact cell. Further, the recesses can also be used as a leakage structure, which can form a hot spot prevention structure when used with a conductive doped block, thereby reducing the risk of hot spots of the back contact cell.

[0008] Optionally, the upper part of the side wall of the recess is enclosed by the first doped layer in the laminated structure.

[0009] Optionally, the lower part of the side wall of the recess is enclosed by the semiconductor substrate.

[0010] Optionally, a conductive doped block is arranged in the recess, and the conductive doped block is of the same conductive type as the second doped layer.

[0011] Optionally, a part of the second doped layer in the stacked structure is recessed downward into the recess to form the conductive doped block.

[0012] Optionally, the conductive doped block and the part of the first doped layer in the stacked structure surrounding the recess are electrically connected, and form a side wall abutting surface.

[0013] Optionally, a dielectric layer is arranged between the conductive doped block and the part of the first doped layer in the stacked structure surrounding the recess, and at least one leakage channel is formed in the dielectric layer.

[0014] Optionally, the dielectric layer is interrupted in a partial region to form the leakage channel; or

[0015] The thickness of the dielectric layer in at least a partial region is less than or equal to 7 nm to form the leakage channel.

[0016] Optionally, the part of the semiconductor substrate surrounding the recess is formed with a prismatic structure.

[0017] Optionally, the longitudinal cross-sectional shape of the recess is a reverse triangular shape, a square shape, a reverse trapezoidal shape, a polygonal shape, or a special shape.

[0018] The transverse cross-sectional shape of the recess is a triangular shape, a square shape, a circular shape, an elliptical shape, a trapezoidal shape, a polygonal shape, or a special shape.

[0019] Optionally, the side surface of the first doped layer in the stacked structure and the second doped layer are electrically connected, and form a side surface abutting surface.

[0020] Optionally, the recess is arranged close to the side surface abutting surface.

[0021] Optionally, the total leakage area of the side wall of a single recess is not greater than the total leakage area of the side surface abutting surface.

[0022] In a second aspect of the present application, a photovoltaic module is provided, wherein the photovoltaic module comprises:

[0023] a cell string formed by electrically connecting a plurality of the aforementioned back contact cells; and

[0024] an encapsulation layer covering the surface of the cell string.

[0025] The above and other objects, advantages and features of the present application will become more apparent from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0026] Features, advantages, and example embodiments of the present application will be described below with reference to the accompanying drawings, in which like reference numerals refer to like elements, and wherein:

[0027] Figure 1 is a partial schematic view of partial components of a back contact cell of an embodiment of the present application, wherein the recesses are shown.

[0028] Figure 2 is a partial schematic view of partial components of a back contact cell of an embodiment of the present application.

[0029] Figure 3 is a partial enlarged schematic view of a back contact cell of Figure 1 , wherein the dielectric layer is shown.

[0030] Figure 4 is another partial enlarged schematic view of a back contact cell of Figure 1 , wherein the dielectric layer is shown.

[0031] Figure 5 is a partial enlarged schematic view of a semiconductor substrate and recesses of a back contact cell of Figure 1 , wherein the prongs are shown.

[0032] Figure 6 is a schematic view of recesses of different longitudinal cross-sectional shapes.

[0033] Figure 7 is a schematic view of recesses of different cross-sectional shapes.

[0034] Figure 8 is a schematic view of a distribution relationship of a first doped layer and a second doped layer of a back contact cell of an embodiment of the present application.

[0035] Figure 9 is another schematic view of a distribution relationship of a first doped layer and a second doped layer of a back contact cell of an embodiment of the present application.

[0036] Figure 10 is a SEM image of a back contact cell having recesses of Figure 1 . DETAILED DESCRIPTION

[0037] Embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood, however, that the description that follows is merely exemplary and is not intended to limit the scope of the application. Furthermore, in the following description, well-known structures and techniques have not been described in detail in order to avoid obscuring the concepts of the present application.

[0038] Various structural schematic diagrams according to embodiments of the present application are shown in the drawings. These diagrams are not drawn to scale, in which certain details are exaggerated for clarity and others omitted. The shapes and relative sizes of the various regions, layers, and the relative positions of these regions / layers shown in the drawings are merely exemplary, and in actuality can be different due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes, and relative positions can be additionally designed according to actual needs by those skilled in the art.

[0039] In the context of the present application, when one layer / element is referred to as being located "on" another layer / element, the layer / element can be directly on the other layer / element, or there can be an intervening layer / element therebetween. In addition, if one layer / element is located "on" another layer / element in one orientation, it can be located "under" the other layer / element when the orientation is reversed. In order to make the technical problems to be solved, technical solutions and beneficial effects of the present application more clear, the present application is further described in detail below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present application, and are not intended to limit the present application.

[0040] In addition, the terms "first", "second", etc. are used only for the purpose of description, and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Thus, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0041] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "contacting", etc. should be understood broadly, for example, can be fixed connection, or detachable connection, or integrally connected; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through an intermediate medium; can be internal communication of two elements, or interaction relationship between two elements; can be direct contact, or indirect contact through an intermediate medium, or electrical contact; can be full surface contact, or local contact, or point contact, etc. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] The present application provides a back contact cell 100, wherein, as Figure 1 and Figure 2As shown, the back contact cell 100 comprises: a semiconductor substrate 101, a first doped layer 200 and a second doped layer 300; the main body part 204 of the first doped layer and the main body part 304 of the second doped layer are alternately distributed on the back light side of the semiconductor substrate 101, and the conductive types of the first doped layer 200 and the second doped layer 300 are opposite; a part of the second doped layer 300 is overlapped on a part of the first doped layer 200 to form a laminated structure 600; wherein one or more pits 601 are formed at the laminated structure 600.

[0043] In the back contact cell 100 of the embodiment of the present application, the laminated structure 600 is formed by overlapping a part of the second doped layer 300 on a part of the first doped layer 200, and one or more pits 601 are formed at the laminated structure 600, which can play a light trapping role, improve the light trapping capability of the back contact cell 100, effectively reduce the reflection of light, increase the scattering and coupling of light, and improve the photoelectric conversion efficiency; further, the one or more pits 601 can also be used as a leakage structure, and when used with the conductive doped block 602, a hot spot prevention structure can be formed, which is beneficial to reduce the risk of hot spot of the back contact cell 100, i.e. reduce the risk of burning out of the back contact cell 100 due to local heat concentration.

[0044] The embodiment of the present application also provides a photovoltaic module (not shown in the figure), wherein the photovoltaic module comprises a cell string formed by electrically connecting the aforementioned back contact cell 100, and a packaging layer covering the surface of the cell string. The photovoltaic module has similar effects to the aforementioned back contact cell 100.

[0045] The back contact cell 100 of the embodiment of the present application will be described in more detail below with reference to the accompanying drawings.

[0046] The back contact cell 100 refers to a solar cell in which the light-facing surface 111 of the cell piece is free of electrodes, and the positive electrode and the negative electrode are both arranged on the back light side 112 of the cell piece, so that the shading of the cell piece by the electrodes can be reduced, the short-circuit current of the cell piece can be increased, and the energy conversion efficiency of the cell piece can be improved.

[0047] The distribution relationship of the first doped layer 200 and the second doped layer 300 of the back contact cell 100 can be two kinds, as shown in Figure 8 and Figure 9 .

[0048] It can be understood that, herein, the first doped layer and the second doped layer are merely for the convenience of description, and the first doped layer 200 and the second doped layer 300 can be interchanged in terms of functions and arrangement positions and the like. Alternatively, the back contact cell 100 comprises: the semiconductor substrate 101, the first doped layer 200 and the second doped layer 300; the main body part 204 of the first doped layer and the main body part 304 of the second doped layer are alternately distributed on the back light side of the semiconductor substrate 101, and the conductive types of the first doped layer 200 and the second doped layer 300 are opposite; a part of the first doped layer 200 is overlapped on a part of the second doped layer 300 to form a laminated structure 600; and one or more pits 601 are formed at the laminated structure 600.

[0049] The embodiments of the present application will be described below in conjunction with Figure 8 The back contact cell 100 of the embodiments of the present application will be described.

[0050] In Figure 8 , the first doped layer 200 comprises the main body part 204 of the first doped layer, and the second doped layer 300 comprises the main body part 304 of the second doped layer. The main body part 204 of the first doped layer and the main body part 304 of the second doped layer are alternately and spacedly distributed in a strip shape. The main body part 204 of the first doped layer and the main body part 304 of the second doped layer have a spacing region 190 therebetween. Specifically, Figure 8 , the main body part 204 of the first doped layer comprises only the strip-shaped part 201 of the first doped layer. The main body part 304 of the second doped layer comprises only the strip-shaped part 301 of the second doped layer. The spacing region 190 is formed between the strip-shaped part 201 of the first doped layer and the strip-shaped part 301 of the second doped layer. Here, the region where the strip-shaped part 201 of the first doped layer is located is a first doped region 191, the region where the strip-shaped part 301 of the second doped layer is located is a second doped region 192, and the spacing region 190 is formed between the first doped region 191 and the second doped region 192.

[0051] The first doped layer 200 can further comprise an extension part 203 of the first doped layer, which extends from a local region of the main body part 204 of the first doped layer towards the second doped layer 300, i.e. from a local region of the strip-shaped part 201 of the first doped layer towards the strip-shaped part 301 of the second doped layer.

[0052] The second doped layer 300 can further comprise an extension part 303 of the second doped layer, which extends from a local region of the main body part 304 of the second doped layer towards the first doped layer 200, i.e. from a local region of the strip-shaped part 301 of the second doped layer towards the strip-shaped part 201 of the first doped layer.

[0053] It should be noted that the extension 203 of the first doped layer is usually integrally formed with the main body 204 of the first doped layer, that is, it extends from a local region of the main body 204 of the first doped layer toward the second doped layer 300. However, the extension 203 of the first doped layer can also be formed separately from the main body 204 of the first doped layer, that is, a conductive block can be formed independently of the main body 204 of the first doped layer using additional processes. This conductive block is structurally connected to or partially stacked with the main body 204 of the first doped layer, and the materials can be the same or different, and the conductivity type can be the same. The extension 303 of the second doped layer is similar to the extension 203 of the first doped layer, and will not be described in detail here.

[0054] Thus, a portion of the aforementioned second doped layer 300 overlaps a portion of the first doped layer 200 to form a stacked structure 600. The "part of the second doped layer" can be a portion of the main body 304 of the second doped layer, or all or part of the extension 303 of the second doped layer. The "part of the first doped layer" can be a portion of the main body 204 of the first doped layer, or all or part of the extension 203 of the first doped layer.

[0055] Regarding the specific structure of the spacer region 190, in the back contact battery 100 of this application embodiment, the spacer region 190 may be a spacer region that is disconnected between the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer, or the spacer region 190 may be a layer spacer region formed by separating the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer using other layer structures such as an insulating layer.

[0056] Regarding the positions of the first doped layer 200 and the second doped layer 300 relative to the semiconductor substrate 101, both the first doped layer 200 and the second doped layer 300 may be formed within the semiconductor substrate 101. Alternatively, both the first doped layer 200 and the second doped layer 300 may be formed on the semiconductor substrate 101. Alternatively, the first doped layer 200 may be formed within the semiconductor substrate 101, and the second doped layer 300 may be formed on the semiconductor substrate 101. In the aforementioned cases, a portion of the second doped layer 300 may overlap a portion of the first doped layer 200 to form a stacked structure 600. Wherein, when the first doped layer 200 is formed within the semiconductor substrate 101 and the second doped layer 300 is formed on the semiconductor substrate 101, typically the height of the main body portion 204 of the first doped layer 200 is higher than the height of the main body portion 304 of the second doped layer 300, and the stacked structure 600 is formed by all or part of the extension portion 303 of the second doped layer overlapping a portion of the main body portion 204 of the first doped layer 200.

[0057] The stacked structure 600 can be formed in the spacer region 190, the first doped region 191, or the second doped region 192. Specifically, when the stacked structure 600 is formed in the spacer region 190, all or part of the extension 303 of the second doped layer overlaps all or part of the extension 203 of the first doped layer; when the stacked structure 600 is formed in the first doped region 191, all or part of the extension 303 of the second doped layer overlaps a portion of the strip-shaped portion 201 of the first doped layer; and when the stacked structure 600 is formed in the second doped region 192, a portion of the strip-shaped portion 301 of the second doped layer overlaps all or part of the extension 203 of the first doped layer.

[0058] For example, Figure 8 In the diagram, at mark 801, the stacked structure 600 is formed at the spacer region 190, where the extension 303 of the second doped layer overlaps the extension 203 of the first doped layer; at mark 802, the stacked structure 600 is formed at the first doped region 191, where the extension 303 of the second doped layer overlaps a portion of the strip-shaped portion 201 of the first doped layer; and at mark 803, the stacked structure 600 is formed at the second doped region 192, where a portion of the strip-shaped portion 301 of the second doped layer overlaps the extension 203 of the first doped layer.

[0059] One or more pits 601 may be formed at the layered structure 600. Figure 1 The diagram shows a recess 601 formed at the laminated structure 600. When multiple recesses 601 are formed at the laminated structure 600, the number of recesses 601 can be, for example, 2, 3, 5, 20, etc., and the multiple recesses 601 are arranged at intervals. The specific number of recesses 601 is not limited. Figure 10 It has Figure 1 SEM image of the back contact battery 100 with the pit 601, where, Figure 10 b) is Figure 10 a) A magnified view of a portion of the image. Figure 10 In the process, the stacked structure 600 is formed at the first doped region 191, and multiple pits 601 are formed at the stacked structure 600.

[0060] In some embodiments of the back contact battery 100 of this application, the upper part of the sidewall of the recess 601 is surrounded by a first doped layer 200 in the stacked structure 600, such as... Figure 1 , Figure 3 and Figure 4 As shown, the pit 601 serves as a light-trapping structure. By configuring the upper part of the sidewall of the pit 601 to be surrounded by the first doped layer 200 in the stacked structure 600, the internal reflection of incident light within the first doped layer 200 can be enhanced, which helps to improve battery efficiency.

[0061] In some embodiments of the present application, in the back contact battery 100, the lower part of the sidewall of the recess 601 is surrounded by a semiconductor substrate 101, such as... Figure 1 , Figure 3 and Figure 4 As shown, the recess 601 serves as a light-trapping structure. By configuring the lower part of the sidewall of the recess 601 to be surrounded by the semiconductor substrate 101, the internal reflection of incident light within the semiconductor substrate 101 can be enhanced, which helps to improve battery efficiency.

[0062] In some embodiments, reference Figure 1 In the back contact battery 100 of this application embodiment, the upper part of the sidewall of the recess 601 is surrounded by the first doped layer 200 in the stacked structure 600, and the lower part of the sidewall of the recess 601 is surrounded by the semiconductor substrate 101. Thus, the recess 601, as a light-trapping structure, can enhance both the internal reflection of incident light within the first doped layer 200 and the internal reflection of incident light within the semiconductor substrate 101, which helps to further improve battery efficiency.

[0063] refer to Figure 1 The upper part of the recess 601 is a through structure with a first upper opening and a first lower opening; while the lower part of the recess 601 is a closed structure with a second upper opening and a second lower closed end, wherein the lower end of the recess 601 is closed by the semiconductor substrate 101; the upper and lower parts of the recess 601 are connected by adjacent and oppositely arranged first lower opening and second upper opening. Specific optional shapes of the recess 601 will be detailed below. The lower end of the recess 601 can typically reach as far as 1 / 2 of the thickness of the semiconductor substrate 101, such as 1 / 5, 1 / 4, 1 / 3, or 1 / 2. The deeper the lower end of the recess 601 is in the semiconductor substrate 101, the larger the affected portion of the semiconductor substrate 101, and the better the enhancement of internal reflection of incident light within the semiconductor substrate 101, but the processing difficulty increases and the processing efficiency decreases.

[0064] In some embodiments of the back contact battery 100 of this application, a conductive doped block 602 may be disposed in the recess 601. The conductive doped block 602 has the same conductivity type as the second doped layer 300, such as... Figure 3 and Figure 4 As shown.

[0065] The conductive doped block 602 can fill the entire space of the pit 601, or it can only fill a part of the space of the pit 601, such as only filling the lower middle part of the pit 601. In this case, only the lower part of the upper part of the sidewall of the pit 601 surrounded by the first doped layer 200 in the stacked structure 600 contacts the conductive doped block 602. Alternatively, the conductive doped block 602 can extend along the side of the first doped layer 200 surrounding the upper part of the sidewall of the pit 601 and fill the lower middle part of the pit 601. In this case, both the upper part of the sidewall of the pit 601 surrounded by the first doped layer 200 in the stacked structure 600 and the lower part of the sidewall surrounded by the semiconductor substrate 101 are in contact with the conductive doped block 602.

[0066] The conductive doped block 602 can be a part of the second doped layer 300 or a structure independent of the second doped layer 300. That is, a conductive doped block 602 can be formed independently of the second doped layer 300 using additional processes. This conductive doped block 602 is structurally connected to or partially stacked with the second doped layer 300, and can be made of the same or different materials, and can have the same conductivity type. In some embodiments, a portion of the second doped layer 300 in the stacked structure 600 is recessed into the pit 601 to form the conductive doped block 602, such as... Figure 1 As shown. By recessing a portion of the second doped layer 300 in the stacked structure 600 downwards to form the conductive doped block 602, it is possible to eliminate the need for separate fabrication of the conductive doped block 602, thereby improving fabrication efficiency.

[0067] In some embodiments, the conductive doped block 602 and a portion of the enclosing recess 601 of the first doped layer 200 in the stacked structure 600 are electrically connected, forming a sidewall mating surface 604, such as Figure 1 As shown. By electrically connecting the conductive doped block 602 and a portion of the enclosing pit 601 of the first doped layer 200 in the stacked structure 600 to form a sidewall mating surface 604, a built-in diode with a low reverse breakdown voltage can be formed at the electrical connection between the conductive doped block 602 and the first doped layer 200. This helps to ensure that the back contact battery 100 has a low reverse breakdown voltage when it is shielded, reducing the risk of hot spots on the back contact battery 100, i.e., reducing the risk of the back contact battery 100 being burned out due to local heat concentration. At the same time, by using multiple small pits 601 to form a hot spot prevention structure, the leakage points are also more evenly distributed, further effectively preventing local overheating of the back contact battery 100.

[0068] In some embodiments, a dielectric layer 603 is disposed between the conductive doped block 602 and a portion of the enclosing pit 601 of the first doped layer 200 in the stacked structure 600, and at least one leakage channel 630 is formed in the dielectric layer 603, such as Figure 3 and Figure 4As shown. By forming at least one leakage channel 630 in the dielectric layer 603, a portion of the conductive doped block 602 and a portion of the first doped layer 200 can be electrically connected through the leakage channel 630. Since the conductive doped block 602 and the first doped layer 200 have opposite doping types, a built-in diode with a low reverse breakdown voltage can be formed between the conductive doped block 602 and the first doped layer 200 by creating a local leakage point. This helps to make the back contact battery 100 have a higher resistance to burn-out when it is shielded, and reduces the risk of hot spots on the back contact battery 100. Furthermore, the dielectric layer 603 can achieve physical separation between the conductive doped block 602 and the first doped layer 200. By controlling the thickness of the dielectric layer 603, for example, setting the thickness of the dielectric layer 603 to be greater than or equal to 13 nm, the dielectric layer 603 itself has certain electrical insulation or semi-insulation properties. Therefore, the portion of the dielectric layer 603 without the leakage channel 630 can achieve electrical isolation between a portion of the conductive doped block 602 and a portion of the first doped layer 200, effectively reducing the direct transport and recombination of charge carriers collected by the conductive doped block 602 and the first doped layer 200, thereby effectively controlling the leakage loss of the back contact battery 100 and enabling the back contact battery 100 to have good working performance. Therefore, in the back contact battery 100 of the present invention, the leakage loss of the back contact battery 100 in the forward voltage region can be effectively controlled by the insulation or semi-insulation characteristics of the part of the dielectric layer 603 where the leakage channel 630 is not provided. At the same time, the leakage channel 630 provided in the dielectric layer 603 reduces the risk of hot spots of the back contact battery 100, realizes the controllability of leakage and electrical isolation, and facilitates the adjustment of the reverse breakdown voltage and working efficiency of the back contact battery 100 to achieve a balance.

[0069] In some embodiments, the dielectric layer 603 is interrupted in a portion of the region, thereby forming a leakage current path 630. For example... Figure 3 As shown, the dielectric layer 603 can be interrupted at the leakage current channel 630. At this time, the thickness of the portion of the dielectric layer 603 with the leakage current channel 630 is 0, and the leakage current channel 630 penetrates the dielectric layer 603.

[0070] In other embodiments, such as Figure 4As shown, the thickness of the dielectric layer 603 in at least a portion of the region is less than or equal to 7 nm, thereby forming a leakage channel 630. The thickness of the dielectric layer 603 in at least a portion of the region can be, for example, 0.0001 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, or 7 nm. By controlling the thickness of the dielectric layer 603 at the leakage channel 630 to below 7 nm, the electrical transport performance of the dielectric layer 603 at the leakage channel 630 is improved, enabling electrical connection and thus leakage at the leakage channel 630, giving the back contact battery 100 anti-hot spot capability. By controlling the specific thickness of the dielectric layer 603 in a portion of the leakage channel 630, the degree of leakage between the conductive doped block 602 and the first doped layer 200 can be adjusted, achieving adjustable leakage magnitude. This, in turn, achieves adjustable leakage and electrical isolation, facilitating the balance between the reverse breakdown voltage and operating efficiency of the back contact battery 100.

[0071] refer to Figure 5 In some embodiments, a portion of the enclosing recess 601 of the semiconductor substrate 101 is formed with a prismatic structure 110. By configuring a portion of the enclosing recess 601 of the semiconductor substrate 101 with a prismatic structure 110, the light trapping ability can be further improved, thereby increasing the photoelectric conversion efficiency. Figure 5 Only a partial portion of the lower part of the enclosing recess 601 of the semiconductor substrate 101 is shown. The specific arrangement of the prismatic structure 110 is not limited; for example, in… Figure 5 In a), the prismatic structure 110 is angled relative to the thickness direction of the semiconductor substrate 101; Figure 5 In b), the prismatic structure 110 is arranged parallel to the thickness direction of the semiconductor substrate 101. The number of prismatic structures 110 can be one or more, and typically multiple prismatic structures 110 are continuously or intermittently arranged around the circumferential portion of the enclosing recess 601 of the semiconductor substrate 101.

[0072] The possible shapes of the pits 601 at the stacked structure 600 are described below.

[0073] In some embodiments, such as Figure 6 As shown, the longitudinal cross-sectional shape of the recess 601 can be an inverted triangle, a square, an inverted trapezoid, a polygon, or an irregular shape.

[0074] In this article, when describing a shape, it includes both the standard inverted triangle shape and similar shapes that are generally similar to it. For example, an inverted triangle shape includes the standard inverted triangle shape and generally inverted triangle shapes; a square shape includes the standard square shape and generally square shapes; an inverted trapezoid shape includes the standard inverted trapezoid shape and generally inverted trapezoid shapes; and a polygon shape includes the standard polygon shape and generally polygon shapes. Irregular shapes are those that differ significantly from standard, common regular shapes and cannot be categorized.

[0075] Figure 6 In a), the longitudinal cross-sectional shape of the pit 601 is an inverted triangle; Figure 6 In b), the longitudinal cross-sectional shape of the pit 601 is square; Figure 6 In c), the longitudinal cross-sectional shape of the pit 601 is an inverted trapezoidal shape; Figure 6 In d), the longitudinal cross-sectional shape of the pit 601 is polygonal; Figure 6 e) and Figure 6 In f), the longitudinal cross-sectional shape of the pit 601 is irregular, wherein, Figure 6 In e), the longitudinal cross-sectional shape of the pit 601 is a "+" shape. Figure 6 In f), the longitudinal cross-sectional shape of the pit 601 is "T". It can be understood that when there are multiple pits 601 in a single stacked structure 600, the longitudinal cross-sectional shapes of these multiple pits 601 can be the same, different, or partially the same and partially different.

[0076] Figure 6 In e), assuming that in the "+" shape, the part above the dashed line in the figure is the upper part of the pit 601 surrounded by the first doped layer 200 in the stacked structure 600, and the part below the dashed line in the figure is the lower part of the pit 601 surrounded by the semiconductor substrate 101, in this case, compared to Figure 6 b) The square shape increases the surface area of ​​the upper sidewall of the pit 601, thereby increasing the volume of the conductive doped block 602 in the pit 601 and increasing the contact area of ​​the leakage channel of the sidewall mating surface 604, which is beneficial to improving the hot spot prevention effect.

[0077] Figure 6 In f), assuming that in the "T" shape, the part above the dashed line in the figure is the upper part of the pit 601 surrounded by the first doped layer 200 in the stacked structure 600, and the part below the dashed line in the figure is the lower part of the pit 601 surrounded by the semiconductor substrate 101, in this case, compared to Figure 6 b) The square shape, due to the presence of the platform portion at the dotted line, can enhance the internal reflection of incident light within the semiconductor substrate 101.

[0078] In some embodiments, such as Figure 7As shown, the cross-sectional shape of the pit 601 can be triangular, square, circular, elliptical, trapezoidal, polygonal, or irregular.

[0079] Figure 7 In a), the cross-sectional shape of the pit 601 is triangular; Figure 7 In b), the cross-sectional shape of the pit 601 is square; Figure 7 In c), the cross-sectional shape of the pit 601 is circular; Figure 7 In d), the cross-sectional shape of the pit 601 is elliptical; Figure 7 In e), the cross-sectional shape of the pit 601 is trapezoidal; Figure 7 In f), the cross-sectional shape of the pit 601 is polygonal; Figure 7 g) and Figure 7 In h), the cross-sectional shape of the pit 601 is irregular. It can be understood that when there are multiple pits 601 in a single stacked structure 600, the cross-sectional shapes of the multiple pits 601 can be the same, different, or partially the same and partially different.

[0080] In some embodiments, such as Figure 1 As shown, the side of the first doped layer 200 in the stacked structure 600 is electrically connected to the second doped layer 300, forming a side mating surface 400.

[0081] In the back contact battery 100 of this embodiment, by overlapping a portion of the second doped layer 300 with a portion of the first doped layer 200, the two are electrically connected to form a side contact surface 400. This allows for the formation of a built-in diode with a low reverse breakdown voltage at the electrical connection between the stacked structure 600 and the second doped layer 300. This helps to ensure that the back contact battery 100 has a low reverse breakdown voltage when it is shielded, reducing the risk of hot spots on the back contact battery 100, i.e., reducing the risk of the back contact battery 100 being burned out due to local heat concentration. The side contact surface 400 and the side wall contact surface 604 at the pit 601 can work together. A portion of the leakage current collected by the side wall contact surface 604 at the pit 601 can be dispersed to the side contact surface 400 of the stacked structure 600, accelerating the transmission speed of the leakage current and further improving the hot spot prevention effect.

[0082] A single stacked structure 600 may include one or more side mating surfaces 400. A single "cell" may be a full cell, a half cell, or a cell of other specifications.

[0083] In some embodiments, the recess 601 is disposed near the side mating surface 400. By disposing the recess 601 near the side mating surface 400, the sidewall mating surface 604 can be disposed near the side mating surface 400, which can further shorten the leakage current transmission path and further improve the hot spot prevention effect. Typically, one or more recesses 601 structures are disposed in half of the stacked structure 600 near the side mating surface 400; and / or, the number of recesses 601 disposed in half of the stacked structure 600 near the side mating surface 400 is greater than the number of recesses 601 disposed in half of the stacked structure 600 away from the side mating surface 400.

[0084] In some embodiments, the total leakage area of ​​the sidewall of a single recess 601 is no greater than the total leakage area of ​​the side mating surface 400. In other words, the total leakage area of ​​the sidewall mating surface 604 is no greater than the total leakage area of ​​the side mating surface 400. The side mating surface 400 is the primary heat-prevention structure, and the sidewall mating surface 604 at the recess 601 is an auxiliary heat-prevention structure. Typically, the total leakage area of ​​the sidewall of a single recess 601 is no greater than the total leakage area of ​​the side mating surface 400; furthermore, the electrical connection at the lapped side mating surface 400 is more reliable than that formed by butt joints.

[0085] The location of the side mating surface 400 varies depending on the location of the stacked structure 600. It can be formed at the junction of the spacer region 190, the first doped region 191, the second doped region 192, the junction of the spacer region 190 and the first doped region 191, or the junction of the spacer region 190 and the second doped region 192. Specifically, when the stacked structure 600 is formed in the spacer region 190, the side mating surface 400 can be formed at the junction of the spacer region 190, the junction of the spacer region 190 and the first doped region 191, or the junction of the spacer region 190 and the second doped region 192; when the stacked structure 600 is formed in the first doped region 191, the side mating surface 400 can be formed at the junction of the first doped region 191, the spacer region 190, and the first doped region 191; when the stacked structure 600 is formed in the second doped region 192, the side mating surface 400 can be formed at the junction of the second doped region 192, the spacer region 190, and the second doped region 192.

[0086] Regarding the contact method between a portion of the first doped layer 200 and a portion of the second doped layer 300, the portion of the first doped layer 200 and the portion of the second doped layer 300 can directly contact each other to form a side mating surface 400; the portion of the first doped layer 200 and the portion of the second doped layer 300 can also indirectly contact each other to form a side mating surface 400. That is, other layer structures may be provided between the portion of the first doped layer 200 and the portion of the second doped layer 300 as needed, as long as the portion of the first doped layer 200 and the portion of the second doped layer 300 can form an electrical connection.

[0087] The following is combined Figure 9 The back contact battery 100 of the present application embodiment will be described.

[0088] exist Figure 9 In the first doped layer 200, a main body portion 204 is included, and in the second doped layer 300, a main body portion 304 is included. The main body portions 204 and 304 are alternately distributed in an interdigitated pattern. A spacing region 190 exists between the main body portions 204 and 304. Specifically, Figure 9 In the first doped layer, the main body 204 includes a strip-shaped portion 201 of the first doped layer and a connecting portion 202 of the first doped layer, wherein the connecting portion 202 of the first doped layer is used to connect multiple strip-shaped portions 201 of the first doped layer. The second doped layer 300 includes a strip-shaped portion 301 of the second doped layer and a connecting portion 302 of the second doped layer, wherein the connecting portion 302 of the second doped layer is used to connect multiple strip-shaped portions 301 of the second doped layer. The region where the strip portion 201 of the first doped layer is located is the first doped region 191, the region where the strip portion 301 of the second doped layer is located is the second doped region 192, the region where the connecting portion 202 of the first doped layer is located is the third doped region 193, and the region where the connecting portion 302 of the second doped layer is located is the fourth doped region 194. In this case, the spacer region 190 can be formed between the strip portion 201 of the first doped layer and the adjacent strip portion 301 of the second doped layer, i.e., between the first doped region 191 and the second doped region 192; formed between the strip portion 201 of the first doped layer and the adjacent connecting portion 302 of the second doped layer, i.e., between the first doped region 191 and the fourth doped region 194; or formed between the connecting portion 202 of the first doped layer and the adjacent strip portion 301 of the second doped layer, i.e., between the third doped region 193 and the second doped region 192.

[0089] The first doped layer 200 may further include an extension 203 of the first doped layer, which extends from a local region of the main body 204 of the first doped layer toward the second doped layer 300, that is, from the strip-shaped portion 201 of the first doped layer or the connecting portion 202 of the first doped layer toward the second doped layer 300. Specifically, the extension 203 of the first doped layer extends from a local region of the strip-shaped portion 201 of the first doped layer toward the strip-shaped portion 301 or the connecting portion 302 of the second doped layer, or extends from all or part of the connecting portion 202 of the first doped layer toward the strip-shaped portion 301 of the second doped layer.

[0090] The second doped layer 300 may further include an extension 303 of the second doped layer, which extends from a local region of the main body portion 304 of the second doped layer toward the first doped layer 200, that is, from the strip-shaped portion 301 of the second doped layer or the connecting portion 302 of the second doped layer toward the first doped layer 200. Specifically, the extension 303 of the second doped layer extends from a local region of the strip-shaped portion 301 of the second doped layer toward the strip-shaped portion 201 or the connecting portion 202 of the first doped layer, or extends from all or part of the connecting portion 302 of the second doped layer toward the strip-shaped portion 201 of the first doped layer.

[0091] and Figure 8 similar, Figure 9 The extension 203 of the first doped layer is usually integrally formed with the main body 204 of the first doped layer; however, the extension 203 of the first doped layer may also be formed separately from the main body 204 of the first doped layer. The extension 303 of the second doped layer is similar to the extension 203 of the first doped layer and will not be described in detail here.

[0092] Thus, in the aforementioned second doped layer 300, a portion overlaps a portion of the first doped layer 200 to form the stacked structure 600. The "partial portion of the second doped layer" can be a portion of the strip-shaped portion 301 of the second doped layer, or all or part of the connecting portion 302 of the second doped layer, or all or part of the extension portion 303 of the second doped layer. Similarly, the "partial portion of the first doped layer" can be a portion of the strip-shaped portion 201 of the first doped layer, or all or part of the connecting portion 202 of the first doped layer, or all or part of the extension portion 203 of the first doped layer. It should be understood that typically, a portion of the second doped layer 300 overlaps a portion of the first doped layer 200 located adjacent to it to form the stacked structure 600.

[0093] The formation location of the stacked structure 600 can be in the spacer region 190, the first doped region 191, the second doped region 192, the third doped region 193, and the fourth doped region 194. Specifically, when the stacked structure 600 is formed in the spacer region 190, all or part of the extension 303 of the second doped layer overlaps all or part of the extension 203 of the first doped layer; when the stacked structure 600 is formed in the first doped region 191, all or part of the extension 303 of the second doped layer overlaps a portion of the strip-shaped portion 201 of the first doped layer; when the stacked structure 600 is formed in the second doped region 192, a portion of the strip-shaped portion 301 of the second doped layer overlaps all or part of the extension 203 of the first doped layer; when the stacked structure 600 is formed in the third doped region 193, all or part of the extension 303 of the second doped layer overlaps all or part of the connecting portion 202 of the first doped layer; and when the stacked structure 600 is formed in the fourth doped region 194, all or part of the connecting portion 302 of the second doped layer overlaps all or part of the extension 203 of the first doped layer.

[0094] For example, Figure 9 In the diagram, at mark 901, the stacked structure 600 may be such that at the spacer region 190, the extension 303 of the second doped layer (specifically, the extension 303 of the second doped layer extends from the strip-shaped portion 301 of the second doped layer toward the connecting portion 202 of the first doped layer) overlaps with the extension 203 of the first doped layer (specifically, the extension 203 of the first doped layer extends from the connecting portion 202 of the first doped layer toward the strip-shaped portion 301 of the second doped layer); at mark 902, the stacked structure 600 may be at the first doped region 191, the extension of the second doped layer... The extension 303 of the second doped layer (specifically, the extension 303 of the second doped layer extends from the strip portion 301 of the second doped layer toward the strip portion 201 of the first doped layer) overlaps over a portion of the strip portion 201 of the first doped layer; at reference 903, the stacked structure 600 may be formed at the first doped region 191, with the extension 303 of the second doped layer (specifically, the extension 303 of the second doped layer extends from the connecting portion 302 of the second doped layer toward the strip portion 201 of the first doped layer) overlapping over a portion of the strip portion 201 of the first doped layer.

[0095] The specific structure of the spacer region 190, the number of pits 601, the shape of the pits 601, the formation location of the side mating surface 400, the position of the first doped layer 200 and the second doped layer 300 relative to the semiconductor substrate 101, and the contact method between a portion of the first doped layer 200 and a portion of the second doped layer 300, etc., are related to... Figure 8The back contact battery 100 is similar in part, and only some features are shown below.

[0096] In some embodiments, in the back contact battery 100 of this application, the upper part of the sidewall of the recess 601 is surrounded by a first doped layer 200 in the stacked structure 600. The effect is similar to that described above, and will not be repeated here.

[0097] In some embodiments, in the back contact battery 100 of this application, the lower part of the sidewall of the recess 601 is surrounded by a semiconductor substrate 101. The effect is similar to that described above, and will not be repeated here.

[0098] In some embodiments, reference Figure 1 In the back contact battery 100 of this application embodiment, the upper part of the sidewall of the recess 601 is surrounded by the first doped layer 200 in the stacked structure 600, and the lower part of the sidewall of the recess 601 is surrounded by the semiconductor substrate 101. The effect is similar to that described above, and will not be repeated here.

[0099] In some embodiments, a conductive doped block 602 may be disposed in the recess 601, and the conductive doped block 602 has the same conductivity type as the second doped layer 300. The effect is similar to that described above, and will not be repeated here.

[0100] In some embodiments, the conductive doped block 602 and a portion of the enclosing recess 601 of the first doped layer 200 in the stacked structure 600 are electrically connected to form a sidewall mating surface 604. The effect is similar to that described above and will not be repeated here.

[0101] In some embodiments, a dielectric layer 603 is disposed between the conductive doped block 602 and a portion of the enclosing pit 601 of the first doped layer 200 in the stacked structure 600, and at least one leakage channel 630 is formed in the dielectric layer 603. The effect is similar to that described above and will not be repeated here.

[0102] In some embodiments, the dielectric layer 603 is interrupted in a portion of the region, thereby forming a leakage current path 630. For example... Figure 3 As shown, the dielectric layer 603 can be interrupted at the leakage current path 630. The effect is similar to that described above, and will not be repeated here.

[0103] In other embodiments, such as Figure 4 As shown, the dielectric layer 603 has a thickness of less than or equal to 7 nm in at least a portion of the region, thereby forming a leakage channel 630. The effect is similar to that described above and will not be repeated here.

[0104] In some embodiments, such as Figure 1As shown, the side surface of the first doped layer 200 in the stacked structure 600 is electrically connected to the second doped layer 300, forming a side mating surface 400. The effect is similar to that described above, and will not be repeated here.

[0105] As for the location of the side mating surface 400, similar to the previous description, it can be at the junction of the spacer region 190, the first doped region 191, the second doped region 192, the third doped region 193, the fourth doped region 194, the junction of the spacer region 190 and the first doped region 191 (also referred to as the junction of the spacer region 190 and the strip portion 201 of the first doped layer), the junction of the spacer region 190 and the second doped region 192 (also referred to as the junction of the spacer region 190 and the strip portion 301 of the second doped layer), the junction of the spacer region 190 and the third doped region 193 (also referred to as the junction of the spacer region 190 and the extension portion 203 of the first doped layer), the junction of the spacer region 190 and the fourth doped region 194 (also referred to as the junction of the spacer region 190 and the connecting portion 302 of the second doped layer), etc., which will not be elaborated here.

[0106] The following is combined Figure 1 and Figure 2 The overall structure of the back contact battery 100 according to the embodiments of this application will be described.

[0107] like Figure 1 and Figure 2 As shown, the back contact battery 100 includes: a semiconductor substrate 101, a first doped layer 200, and a second doped layer 300; the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer are alternately distributed on the back surface side of the semiconductor substrate 101, and the conductivity types of the first doped layer 200 and the second doped layer 300 are opposite; the extension portion 303 of the second doped layer overlaps the main body portion 204 of the first doped layer to form a stacked structure 600; wherein, one or more pits 601 are formed at the stacked structure 600. The longitudinal cross-sectional shape of the pit 601 is an inverted triangle shape.

[0108] Figure 1 The back contact battery 100 shown may further include a first dielectric layer 131 located between the first doped layer 200 and the semiconductor substrate 101, a second dielectric layer 132 located between the second doped layer 300 and the semiconductor substrate 101, an insulating layer 150 located between the extension 303 of the second doped layer and the main body 204 of the first doped layer in the stacked structure 600, a surface passivation layer 140 located above the first doped layer 200 and the second doped layer 300, a first electrode 121, and a second electrode 122.

[0109] It should be noted that, in terms of the specific electrode structure of the positive and negative electrodes, the back contact battery 100 of this embodiment can be a "gridless back contact battery". In this case, the electrode structure of the back contact battery only includes multiple current collector electrodes (first electrode 121, second electrode 122). The current collector electrodes can also be called fine grid lines. These multiple current collector electrodes can extend along a first direction and be spaced apart along a second direction. Alternatively, the back contact battery 100 of this embodiment can also be a "grid-supported back contact battery". In this case, the back contact battery includes multiple current collector electrodes and multiple busbar structures (not shown in the figure). The busbar structure can also be called a busbar electrode. The busbar structure is spaced apart along the first direction and extends along the second direction, and is electrically coupled to the current collector electrodes with the same conductivity type as itself. The busbar structure can be a structure that extends through the entire battery cell, or it can be a structure that only extends through a part of the battery cell.

[0110] The materials of each layer and electrode of the back contact battery 100 in this embodiment of the invention can refer to any material that can be used to prepare the back contact battery 100 in the prior art. The materials of each layer are briefly described below.

[0111] The semiconductor substrate can be a silicon substrate. The silicon substrate can be N-type or P-type silicon, with a thickness of 30-500 micrometers. The backlighting side and the light-facing side of the semiconductor substrate can be planar. Alternatively, the light-facing side of the semiconductor substrate can also be textured.

[0112] The first doped layer can be N-type, in which case the second doped layer is P-type; alternatively, the first doped layer can also be P-type, in which case the second doped layer is N-type. Regarding the specific materials of the first and second doped layers, the N-type doped layer can be one or more of monocrystalline silicon, polycrystalline silicon, amorphous silicon, microcrystalline silicon, nanocrystalline silicon, and silicon oxide, and its N-type dopant element can be one or more of carbon, nitrogen, phosphorus, arsenic, antimony, bismuth, oxygen, sulfur, selenium, and tellurium; the P-type doped semiconductor layer can be one or more of monocrystalline silicon, polycrystalline silicon, amorphous silicon, microcrystalline silicon, nanocrystalline silicon, and silicon oxide, and its P-type dopant element can be one or more of boron, aluminum, gallium, indium, thallium, carbon, and nitrogen. The thickness of the first and second doped layers can be set as needed, for example, from 3-3000 nm.

[0113] The first and second dielectric layers can be one or more of oxides, nitrides, oxynitrides, halides, carbides, and silicon, and their thickness can be set as needed, for example, 0-10 nm. Preferably, the dielectric layer, the first dielectric layer, and the second dielectric layer can be one or more of silicon oxide, aluminum oxide, titanium oxide, niobium oxide, boron oxide, gallium oxide, tin oxide, hafnium oxide, tantalum oxide, silicon nitride, silicon oxynitride, silicon carbide, lithium fluoride, magnesium fluoride, amorphous silicon, microcrystalline silicon, nanocrystalline silicon, etc.

[0114] The insulating layer can be one or more of oxides, nitrides, oxynitrides, halides, carbides, and silicon, and its thickness can be set as needed, for example, 0-5000 nm. Preferably, the insulating layer can be one or more of phosphosilicate glass, borosilicate glass, aluminosilicate glass, gallium silicon glass, silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, silicon carbide, and amorphous silicon.

[0115] The surface passivation layer can be one or more of oxides, nitrides, oxynitrides, halides, carbides, and silicon, and its thickness can be set as needed, for example, 0-1000 nm. Preferably, the surface passivation layer can be one or more of silicon oxide, aluminum oxide, titanium oxide, niobium oxide, boron oxide, gallium oxide, tin oxide, hafnium oxide, tantalum oxide, indium oxide, tungsten oxide, zinc oxide, silicon nitride, silicon oxynitride, silicon carbide, lithium fluoride, magnesium fluoride, amorphous silicon, microcrystalline silicon, and nanocrystalline silicon.

[0116] The method for fabricating the back contact battery 100 in this embodiment of the invention can refer to any existing method that can be used to fabricate the back contact battery 100, and is not limited thereto. For the pit structure, it can be obtained using existing laser etching or other methods.

[0117] 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.

[0118] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "one example," "some embodiments," or "preferred embodiment," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0119] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the embodiments described above. Various modifications and substitutions can be applied to the above embodiments without departing from the scope of the present invention.

Claims

1. A back-contact battery, wherein, The back contact battery includes: a semiconductor substrate, a first doped layer, and a second doped layer; The main body portions of the first doped layer and the main body portions of the second doped layer are alternately distributed on one side of the backlight surface of the semiconductor substrate, and the first doped layer and the second doped layer have opposite conductivity types; A portion of the second doped layer overlaps a portion of the first doped layer to form a stacked structure; wherein one or more pits are formed in the stacked structure; The first doped layer and the second doped layer in the stacked structure are electrically connected to form a side mating surface; The total leakage area of ​​the sidewall of a single pit is less than the total leakage area of ​​the side mating surface.

2. The back contact battery according to claim 1, wherein, The upper part of the sidewall of the pit is surrounded by the first doped layer in the stacked structure.

3. The back contact battery according to claim 1, wherein, The lower part of the sidewall of the pit is surrounded by the semiconductor substrate.

4. The back contact battery according to claim 1, wherein, A conductive doped block is disposed in the pit, and the conductive doped block has the same conductivity type as the second doped layer.

5. The back contact battery according to claim 4, wherein, A portion of the second doped layer in the stacked structure is recessed into the pit to form the conductive doped block.

6. The back contact battery according to claim 4, wherein, The conductive doped block and the portion of the first doped layer in the stacked structure that encloses the pit are electrically connected, forming a sidewall mating surface.

7. The back contact battery according to claim 4, wherein, A dielectric layer is disposed between the conductive doped block and the portion of the first doped layer in the stacked structure that encloses the pit, and at least one leakage channel is formed in the dielectric layer.

8. The back contact battery according to claim 7, wherein, The dielectric layer is interrupted in a certain area, thereby forming the leakage current path; or The dielectric layer has a thickness of less than or equal to 7 nm in at least a portion of the region, thereby forming the leakage current channel.

9. The back contact battery according to claim 1, wherein, The portion of the semiconductor substrate surrounding the pit has a prismatic structure.

10. The back contact battery according to claim 1, wherein, The longitudinal cross-sectional shape of the pit is an inverted triangle, a square, an inverted trapezoid, a polygon, or an irregular shape; The cross-sectional shape of the pit can be triangular, square, circular, elliptical, trapezoidal, polygonal, or irregular.

11. The back contact battery according to claim 1, wherein, The recess is located near the side mating surface.

12. A photovoltaic module, wherein, The photovoltaic module includes: A battery string, wherein the battery string is formed by electrically connecting a plurality of back-contact batteries as described in any one of claims 1-11; as well as An encapsulation layer that covers the surface of the battery string.

Images