Back contact cell and photovoltaic module

Abstract

The present application provides a back contact cell. The back contact cell comprises a semiconductor substrate, a first doped layer, and a second doped layer. Main portions of the first doped layer and main portions of the second doped layer are alternately distributed on a non-light-receiving 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, and one or more pits are formed in the stacked structure. The present application further provides a photovoltaic module. In the back contact cell of the present application, one or more pits are formed in the stacked structure, thereby improving the light trapping capability of the back contact cell.

Description

Back contact batteries and photovoltaic modules Technical Field

[0001] This application relates to the field of photovoltaic technology, specifically to a back contact battery and a photovoltaic module. Background Technology

[0002] Back-contact solar cells are those where the light-facing side of the cell has no electrodes, and both the positive and negative electrodes are located on the back-facing side. This reduces shading of the cells by the electrodes, increases the short-circuit current, and improves the energy conversion efficiency. However, in practical use, bird droppings, leaves, dust, and other obstructions may fall onto the module, blocking the corresponding cells. This shading causes the cells to overheat, resulting in hot spots. If the temperature of these hot spots exceeds a certain threshold, it can lead to problems such as photovoltaic module delamination, backsheet burning, and glass shattering, rendering the entire solar cell unusable and potentially posing a fire hazard. However, existing back-contact solar cells with anti-hot-spot structures suffer from excessive leakage current and localized overheating.

[0003] Therefore, there is a need to provide an improved back-contact cell and photovoltaic module to overcome or reduce at least some of the disadvantages of the prior art. Summary of the Invention

[0004] In a first aspect of this application, a back contact battery is provided, wherein the back contact battery includes: a semiconductor substrate, a first doped layer, and a second doped layer;

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

[0006] 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 at the stacked structure.

[0007] In the back contact battery of this application, a stacked structure is formed by overlapping a portion of the second doped layer with a portion of the first doped layer, and one or more pits are formed at the stacked structure. The one or more pits can play a light trapping role, thereby improving the light trapping ability of the back contact battery. Furthermore, the pits can also be used as a leakage structure. When used in conjunction with a conductive doped block, they can form a hot spot prevention structure, which helps to reduce the hot spot risk of the back contact battery.

[0008] Optionally, the upper part of the sidewall of the pit is surrounded by a first doped layer in the stacked structure.

[0009] Optionally, the lower part of the sidewall of the pit is surrounded by a semiconductor substrate.

[0010] Optionally, a conductive doped block is provided in the pit, and the conductive doped block has the same conductivity type as the second doped layer.

[0011] Alternatively, a portion of the second doped layer in the stacked structure is recessed into a pit to form a conductive doped block.

[0012] Optionally, the conductive doped block is partially electrically connected (also known as electrically connected) to the enclosing pit of the first doped layer in the stacked structure, forming a sidewall mating surface.

[0013] Optionally, a dielectric layer is provided between the conductive doped block and the portion of the enclosing pit of the first doped layer in the stacked structure, and at least one leakage channel is formed in the dielectric layer.

[0014] Optionally, the dielectric layer is interrupted in a certain area, thereby forming a leakage current path; or

[0015] The dielectric layer has a thickness of less than or equal to 7 nm in at least a portion of the region, thereby forming a leakage current path.

[0016] Optionally, the portion of the enclosing pit in the semiconductor substrate is formed with a prismatic structure.

[0017] Optionally, the longitudinal cross-sectional shape of the pit can be an inverted triangle, a square, an inverted trapezoid, a polygon, or an irregular shape;

[0018] The cross-sectional shape of the pit can be triangular, square, circular, elliptical, trapezoidal, polygonal, or irregular.

[0019] Optionally, the side of the first doped layer in the stacked structure is electrically connected to the second doped layer to form a side mating surface.

[0020] Optionally, the recess is positioned near the side mating surface.

[0021] Optionally, the total leakage area of ​​the sidewall of a single pit is not greater than the total leakage area of ​​the side mating surfaces.

[0022] Optionally, the back contact battery further includes a plurality of current collector electrodes extending along a first direction and spaced apart along a second direction, wherein the first direction differs from the second direction, and for the upper part of the sidewall of the pit, its dimension in the second direction decreases along the direction closer to the semiconductor substrate. By giving the upper part of the sidewall of the pit the aforementioned dimensions, the internal reflection of light within the pit can be increased, thereby improving the light trapping capability of the back contact battery.

[0023] Optionally, the back contact battery further includes a plurality of current collector electrodes extending along a first direction and spaced apart along a second direction, wherein the first direction differs from the second direction, and for the lower portion of the sidewall of the pit, its dimension in the second direction decreases along the direction of penetration into the semiconductor substrate. By giving the lower portion of the sidewall of the pit the aforementioned dimensions, the internal reflection of light within the pit can be increased, thereby improving the light trapping capability of the back contact battery.

[0024] Optionally, a first portion of the second doped layer, which is part of the second doped layer, overlaps the first portion of the first doped layer to form the stacked structure; and wherein a portion of the second portion of the second doped layer near the stacked structure is raised in a direction away from the stacked structure to form a raised portion.

[0025] In the back-contact battery of this application, by overlapping a first portion of the second doped layer, which is a part of the second doped layer, with a portion of the first doped layer to form a stacked structure, a built-in diode with a low reverse breakdown voltage can be formed at the electrical connection between the first and second doped layers. This facilitates a lower reverse breakdown voltage when the back-contact battery is shielded, reducing the risk of hot spots. By tilting a portion of the second doped layer near the stacked structure away from the stacked structure to form a tilted portion, a gap can be formed between the tilted portion and the stacked structure. The existence of this gap can separate a portion of the first doped layer and the second portion of the second doped layer in the stacked structure, thereby preventing the formation of a leakage area at the gap and dispersing leakage points to avoid local overheating. The presence of the tilted portion can reduce the proportion of leakage contact area, thereby minimizing the loss of battery conversion efficiency caused by PN region contact while improving the hot spot effect.

[0026] Optionally, another portion of the second part of the second doped layer is closely attached to the stacked structure to form an adhesion portion;

[0027] In the third direction, multiple raised portions and multiple adhered portions alternate; the third direction extends parallel to the side of the first doped layer in the stacked structure, opposite to the second part of the second doped layer.

[0028] Optionally, the first doped layer in the stacked structure is electrically connected to the second portion of the second doped layer, and the side of the first doped layer in the stacked structure opposite to the second portion of the second doped layer forms a side mating surface, wherein the side mating surface has a bent structure.

[0029] Optionally, the bending structure includes multiple docking sections that are bent and connected in a direction parallel to the backlight surface.

[0030] Optionally, the docking section has a plurality of protruding portions that protrude toward the second portion of the second doped layer and a plurality of recessed portions that are recessed away from the second portion of the second doped layer.

[0031] Optionally, the raised portion is formed at a position corresponding to the protruding portion in the second portion of the second doped layer; or

[0032] The raised portion is formed at a position corresponding to the recessed portion in the second part of the second doped layer; or

[0033] The raised portion is formed at a position in the second part of the second doped layer corresponding to the recessed portion adjacent to the raised portion.

[0034] Optionally, an air gap is defined therebetween the raised portion, the first doped layer in the stacked structure, and the semiconductor substrate.

[0035] Optionally, the back contact battery further includes a surface passivation layer covering the first doped layer, the second doped layer, and the stacked structure, wherein the surface passivation layer extends into the air gap at the raised portion, thereby filling part or all of the air gap.

[0036] Optionally, there is a gap region between the main body portion of the first doped layer and the main body portion of the second doped layer;

[0037] The second doped layer also includes an extension of the second doped layer that extends across the spacer region and over a portion of the first doped layer to form a stacked structure, wherein the aforementioned first portion and the aforementioned second portion of the second doped layer are part of the extension of the second doped layer.

[0038] Optionally, there is a gap region between the main body portion of the first doped layer and the main body portion of the second doped layer;

[0039] The first doped layer further includes an extension of the first doped layer, and the second doped layer further includes an extension of the second doped layer. The extension of the second doped layer overlaps the extension of the first doped layer in the spacer region to form a stacked structure, wherein the aforementioned first portion and the aforementioned second portion of the second doped layer are part of the extension of the second doped layer.

[0040] Optionally, there is a gap region between the main body portion of the first doped layer and the main body portion of the second doped layer;

[0041] The first doped layer also includes an extension of the first doped layer, which extends across the spacer region and extends below the main body of the second doped layer to form a stacked structure, wherein the aforementioned first portion of the second doped layer is part of the main body of the second doped layer.

[0042] In a second aspect of this application, a photovoltaic module is provided, wherein the photovoltaic module comprises:

[0043] A battery string, formed by the electrical connection of multiple back-contact batteries as described above; and

[0044] Encapsulation layer, which covers the surface of the battery string.

[0045] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments of this application in conjunction with the accompanying drawings. Attached Figure Description

[0046] The features, advantages, and exemplary embodiments of this application will now be described with reference to the accompanying drawings, in which the same reference numerals indicate the same elements, and wherein:

[0047] Figure 1 is a partial schematic diagram of a portion of the back contact battery according to an embodiment of this application, showing a recess.

[0048] Figure 2 is a partial schematic diagram of some components of the back contact battery according to an embodiment of this application.

[0049] Figure 3 is a partially enlarged schematic diagram of the back contact battery of Figure 1, showing the dielectric layer.

[0050] Figure 4 is another partially enlarged schematic diagram of the back contact battery in Figure 1, showing the dielectric layer.

[0051] Figure 5 is a partially enlarged schematic diagram of the semiconductor substrate and pit of the back contact battery in Figure 1, showing the ridges.

[0052] Figure 6 is a schematic diagram of pits with different longitudinal cross-sectional shapes.

[0053] Figure 7 is a schematic diagram of pits with different cross-sectional shapes.

[0054] Figure 8 is a schematic diagram showing the distribution relationship of the first doped layer and the second doped layer of the back contact battery according to an embodiment of this application.

[0055] Figure 9 is a schematic diagram showing another distribution relationship between the first doped layer and the second doped layer of the back contact battery according to an embodiment of this application.

[0056] Figure 10 is a SEM image of a back contact battery with the pit shown in Figure 1.

[0057] Figure 11 is a partial schematic diagram of a portion of the back contact battery according to an embodiment of this application, showing the raised portion.

[0058] Figure 12 is another partial schematic diagram of the back contact battery of Figure 11, showing the bonding portion.

[0059] Figure 13 is a schematic diagram showing the arrangement of the side mating surface, raised portion, and fitting portion of the back contact battery in Figure 11.

[0060] Figure 14 is a partial schematic diagram of some components of a back contact battery according to another embodiment of this application.

[0061] Figure 15 is a schematic diagram of one embodiment of the back contact battery of Figure 11.

[0062] Figure 16 is a schematic diagram of another embodiment of the back contact battery of Figure 11.

[0063] Figure 17 is a cross-sectional schematic diagram of the back contact battery according to an embodiment of this application.

[0064] Figure 18 is a schematic diagram of a single side mating surface of the back contact battery in Figure 11.

[0065] Figure 19 is a SEM image of a back contact battery with a raised portion. Detailed Implementation

[0066] The embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of this application. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0067] The accompanying drawings illustrate various structural schematics according to embodiments of this application. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0068] In the context of this application, when a layer / element is referred to as being "on top of" another layer / element, the layer / element can be directly on top of the other layer / element, or there can be an intermediate layer / element between them. Furthermore, if a layer / element is "on top of" another layer / element in one orientation, then when the orientation is reversed, the layer / element can be "below" the other layer / element. To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0069] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0070] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "contact" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal communication between two components or the interaction between two components; direct contact or indirect contact through an intermediate medium; electrical contact; full-surface contact, partial contact, or point contact, etc. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0071] Implementation Plan A

[0072] This application provides a back contact battery 100, wherein, as shown in Figures 1 and 2, 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 of the first doped layer (shown as 204 in Figure 9) and the main body portion of the second doped layer (shown as 304 in Figure 9) are alternately distributed on the back surface side of the semiconductor substrate 101, and the first doped layer 200 and the second doped layer 300 have opposite conductivity types; a portion of the second doped layer 300 overlaps a portion of the first doped layer 200 to form a stacked structure 600; wherein one or more pits 601 are formed at the stacked structure 600.

[0073] In the back contact battery 100 of this application embodiment, a stacked structure 600 is formed by overlapping a portion of the second doped layer 300 on a portion of the first doped layer 200, and one or more pits 601 are formed at the stacked structure 600. The one or more pits 601 can play a light trapping role, improve the light trapping ability of the back contact battery 100, effectively reduce light reflection, increase light scattering and coupling, and improve photoelectric conversion efficiency. Furthermore, the one or more pits 601 can also be used as a leakage structure. When used in conjunction with the conductive doped block 602, they can form a hot spot prevention structure, which helps to reduce the hot spot risk of the back contact battery 100, that is, reduce the risk of the back contact battery 100 being burned due to local heat concentration.

[0074] This application also provides a photovoltaic module (not shown in the figures), which includes a battery string formed by electrical connections of the aforementioned back contact battery 100 and an encapsulation layer covering the surface of the battery string. This photovoltaic module has effects similar to those of the aforementioned back contact battery 100.

[0075] The back contact battery 100 of this application embodiment will now be described in more detail with reference to the accompanying drawings.

[0076] A back-contact cell 100 refers to a solar cell in which the light-facing surface 111 of the cell has no electrodes, and the positive and negative electrodes are both located on the back-facing surface 112 of the cell. This reduces the shading of the cells by the electrodes, increases the short-circuit current of the cells, and improves the energy conversion efficiency of the cells.

[0077] The distribution relationship of the first doped layer 200 and the second doped layer 300 of the back contact battery 100 can be two, as shown in Figure 8 and Figure 9 respectively.

[0078] It is understood that in this document, "first doped layer" and "second doped layer" are used only for ease of description, and the first doped layer 200 and the second doped layer 300 can be interchanged in terms of function and placement. Alternatively, 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; a portion of the first doped layer 200 overlaps a portion of the second doped layer 300 to form a stacked structure 600; wherein one or more pits 601 are formed at the stacked structure 600.

[0079] The back contact battery 100 of this application embodiment will be described below with reference to FIG8.

[0080] In Figure 8, the first doped layer 200 includes a main body portion of the first doped layer, and the second doped layer 300 includes a main body portion of the second doped layer. The main bodies of the first and second doped layers are arranged in alternating stripe patterns. A spacer region 190 is formed between the main bodies of the first and second doped layers. Specifically, in Figure 8, the main body portion of the first doped layer includes only the stripe portion 201 of the first doped layer. The main body portion of the second doped layer includes only the stripe portion 301 of the second doped layer. The spacer region 190 is formed between the stripe portion 201 of the first doped layer and the stripe portion 301 of the second doped layer. Here, the region where the stripe portion 201 of the first doped layer is located is the first doped region 191, the region where the stripe portion 301 of the second doped layer is located is the second doped region 192, and the spacer region 190 is formed between the first doped region 191 and the second doped region 192.

[0081] 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 a local region of the strip portion 201 of the first doped layer toward the strip portion 301 of the second doped layer 300.

[0082] 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 304 of the second doped layer toward the first doped layer 200, that is, from a local region of the strip portion 301 of the second doped layer toward the strip portion 201 of the first doped layer.

[0083] 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.

[0084] Thus, in the aforementioned second doped layer 300 overlapping 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, and 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] For example, in Figure 8, 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.

[0089] One or more pits 601 may be formed at the stacked structure 600. Figure 1 shows a pit 601 formed at the stacked structure 600. When multiple pits 601 are formed at the stacked structure 600, the number of pits 601 may be, for example, 2, 3, 5, 20, etc., and the multiple pits 601 are arranged at intervals. The specific number of pits 601 is not limited. Figure 10 is a SEM image of a back contact cell 100 having the pits 601 of Figure 1, wherein Figure 10b) is a partial enlarged view of Figure 10a). In Figure 10, the stacked structure 600 is formed at the first doped region 191, and multiple pits 601 are formed at the stacked structure 600.

[0090] 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, as shown in Figures 1, 3, and 4. The recess 601 serves as a light-trapping structure. By configuring the upper part of the sidewall of the recess 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.

[0091] 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, as shown in Figures 1, 3, and 4. 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.

[0092] In some embodiments, referring to FIG1, 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.

[0093] Referring 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.

[0094] In the back contact battery 100 of this application embodiment, in some embodiments, a conductive doped block 602 may be provided in the pit 601. The conductive doped block 602 has the same conductivity type as the second doped layer 300, as shown in Figures 3 and 4.

[0095] 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.

[0096] 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, with the same conductivity type. In some embodiments, a portion of the second doped layer 300 in the stacked structure 600 is recessed into a recess 601 to form the conductive doped block 602, as shown in FIG1. ​​By forming the conductive doped block 602 by recessing a portion of the second doped layer 300 in the stacked structure 600, the conductive doped block 602 can be set without separate processing, improving processing efficiency.

[0097] In some embodiments, the conductive doped block 602 is partially electrically connected to the enclosing recess 601 of the first doped layer 200 in the stacked structure 600, forming a sidewall mating surface 604, as shown in FIG1. ​​It should be understood that the "electrical connection" can be a direct connection or a connection through a conductive film layer. The conductive film layer can be any film layer in the prior art, as long as it can conduct electricity, such as a tunneling oxide layer. By electrically connecting a portion of the enclosing pit 601 of the first doped layer 200 in the stacked structure 600 to the conductive doped block 602 and forming 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.

[0098] In some embodiments, a dielectric layer 603 is disposed between the conductive doped block 602 and a portion of the enclosure 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, as shown in Figures 3 and 4. 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 via 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 facilitates higher burn-out resistance when the back contact battery 100 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 this application embodiment, 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 portion 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 in 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.

[0099] In some embodiments, the dielectric layer 603 is interrupted in a portion to form a leakage current path 630. As shown in FIG3, the dielectric layer 603 may be interrupted at the leakage current path 630. In this case, the thickness of the portion of the dielectric layer 603 with the leakage current path 630 is 0, and the leakage current path 630 penetrates the dielectric layer 603.

[0100] In other embodiments, as shown in FIG4, 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 dielectric layer 603 at the leakage channel 630 exhibits good electrical transport performance, 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, thereby realizing adjustable leakage and electrical isolation, which is beneficial for adjusting the reverse breakdown voltage and operating efficiency of the back contact battery 100 to achieve a balance.

[0101] Referring to FIG5, 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 capability can be further improved, and the photoelectric conversion efficiency can be increased. FIG5 only shows a partial portion of the lower part of the enclosing recess 601 of the semiconductor substrate 101. The specific arrangement of the prismatic structure 110 is not limited. For example, in FIG5a), the prismatic structure 110 is arranged at an angle to the thickness direction of the semiconductor substrate 101; in FIG5b), 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. Typically, multiple prismatic structures 110 are continuously or intermittently spaced around the circumference of a portion of the enclosing recess 601 of the semiconductor substrate 101.

[0102] The possible shapes of the pits 601 at the stacked structure 600 are described below.

[0103] In some embodiments, as shown in FIG6, 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.

[0104] In this article, the description of a shape includes both the standard inverted triangle shape and similar shapes that are generally similar to it. For example, an inverted triangle shape includes both the standard inverted triangle shape and generally inverted triangle shapes; a square shape includes both the standard square shape and generally square shapes; an inverted trapezoid shape includes both the standard inverted trapezoid shape and generally inverted trapezoid shapes; and a polygon shape includes both the standard polygon shape and generally polygon shapes. Irregular shapes are those that differ significantly from standard, common regular shapes and cannot be categorized.

[0105] In Figure 6a), the longitudinal cross-sectional shape of the pit 601 is an inverted triangle; in Figure 6b), the longitudinal cross-sectional shape of the pit 601 is a square; in Figure 6c), the longitudinal cross-sectional shape of the pit 601 is an inverted trapezoid; in Figure 6d), the longitudinal cross-sectional shape of the pit 601 is a polygon; in Figures 6e) and 6f), the longitudinal cross-sectional shape of the pit 601 is irregular, wherein in Figure 6e), the longitudinal cross-sectional shape of the pit 601 is a "+" shape, and in Figure 6f), the longitudinal cross-sectional shape of the pit 601 is a "T" shape. It can be understood that when multiple pits 601 exist in a single laminated structure 600, the longitudinal cross-sectional shapes of these multiple pits 601 can be the same, different, or partially the same and partially different.

[0106] In Figures 6a) and 6c), assuming that in the inverted triangle and inverted trapezoidal shapes, the part above the dashed line 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 is the lower part of the pit 601 surrounded by the semiconductor substrate 101, in this case, compared with the square shape in Figure 6b), the internal reflection of light in the pit can be increased, and the light trapping ability of the back contact cell can be improved.

[0107] In Figure 6e), assuming that in the "+" shape, the part above the dashed line 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 is the lower part of the pit 601 surrounded by the semiconductor substrate 101, in this case, compared with the square shape in Figure 6b), the surface area of ​​the upper sidewall of the pit 601 is increased, which can increase the placement volume of the conductive doped block 602 in the pit 601 and increase the leakage channel contact area of ​​the sidewall mating surface 604, which is beneficial to improving the hot spot prevention effect.

[0108] In Figure 6f), assuming that in the “T” shape, the part above the dashed line 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 is the lower part of the pit 601 surrounded by the semiconductor substrate 101, in this case, compared with the square shape in Figure 6b), the presence of the platform part at the dashed line can enhance the internal reflection of incident light within the semiconductor substrate 101.

[0109] In some embodiments, as shown in FIG7, the cross-sectional shape of the recess 601 can be triangular, square, circular, elliptical, trapezoidal, polygonal, or irregular.

[0110] In Figure 7a), the cross-sectional shape of the pit 601 is triangular; in Figure 7b), the cross-sectional shape of the pit 601 is square; in Figure 7c), the cross-sectional shape of the pit 601 is circular; in Figure 7d), the cross-sectional shape of the pit 601 is elliptical; in Figure 7e), the cross-sectional shape of the pit 601 is trapezoidal; in Figure 7f), the cross-sectional shape of the pit 601 is polygonal; and in Figures 7g) and 7h), the cross-sectional shape of the pit 601 is irregular. It can be understood that when multiple pits 601 exist in a single laminated structure 600, the cross-sectional shapes of these multiple pits 601 can be the same, different, or partially the same and partially different.

[0111] In some embodiments, the back contact battery includes a plurality of current collector electrodes extending along a first direction and spaced apart along a second direction, the first direction being different from the second direction. For the upper portion of the sidewall of the recess, its dimension in the second direction decreases along the direction close to the semiconductor substrate (as shown above the dashed line in Figures 6a and 6c). In some embodiments, for the upper portion of the sidewall of the recess, its cross-sectional dimension in a plane perpendicular to the thickness direction of the semiconductor substrate decreases along the direction close to the semiconductor substrate. By giving the upper portion of the sidewall of the recess the aforementioned dimensions, internal reflection of light within the recess can be increased, thereby improving the light-trapping capability of the back contact battery.

[0112] In some embodiments, the back contact battery includes a plurality of current collector electrodes extending along a first direction and spaced apart along a second direction, the first direction being different from the second direction. For the lower portion of the sidewall of the recess, its dimension in the second direction decreases along the direction of penetration into the semiconductor substrate (as shown below the dashed line in Figures 6a and 6c). In some embodiments, for the lower portion of the sidewall of the recess, its cross-sectional dimension in a plane perpendicular to the thickness direction of the semiconductor substrate decreases along the direction of penetration into the semiconductor substrate. By giving the lower portion of the sidewall of the recess the aforementioned dimensions, internal reflection of light within the recess can be increased, thereby improving the light-trapping capability of the back contact battery.

[0113] In some embodiments, the back contact battery includes a plurality of current collector electrodes extending along a first direction and spaced apart along a second direction, the first direction being different from the second direction. For the upper portion of the sidewall of the recess, its dimension in the second direction decreases along the direction close to the semiconductor substrate, and for the lower portion of the sidewall of the recess, its dimension in the second direction decreases along the direction penetrating the semiconductor substrate (as shown above and below the dashed lines in Figures 6a and 6c). In some embodiments, for the upper portion of the sidewall of the recess, its cross-sectional dimension in a plane perpendicular to the thickness direction of the semiconductor substrate decreases along the direction close to the semiconductor substrate, and for the lower portion of the sidewall of the recess, its cross-sectional dimension in a plane perpendicular to the thickness direction of the semiconductor substrate decreases along the direction penetrating the semiconductor substrate. By having the upper and lower portions of the sidewall of the recess have the aforementioned dimensions, the internal reflection of light within the recess can be further increased, improving the light-trapping capability of the back contact battery.

[0114] In some embodiments, the depth of the upper sidewall of the recess is less than the depth of the lower sidewall in the thickness direction of the semiconductor substrate. For example, the depth of the upper sidewall of the recess in the thickness direction of the semiconductor substrate can be 150nm-450nm (e.g., 150nm, 200nm, 250nm, 450nm, etc.). Alternatively, the depth of the lower sidewall of the recess in the thickness direction of the semiconductor substrate can be greater than 500nm. By having the upper and lower sidewalls of the recess have these depths, the internal reflection of light within the recess can be increased, thereby improving the light-trapping capability of the back-contact battery.

[0115] In some embodiments, the ratio of the depth of the lower sidewall to the depth of the upper sidewall of the pit in the thickness direction of the semiconductor substrate is greater than 1.05 and less than 7. By having this depth ratio, the internal reflection of light within the pit can be increased, improving the light-trapping capability of the back-contact battery. In some cases, the ratio of the depth of the lower sidewall to the depth of the upper sidewall of the pit in the thickness direction of the semiconductor substrate is greater than 1.1 and less than 3. This setting avoids the lower pit being too deep relative to the upper pit. If the lower pit depth exceeds three times the upper pit depth, the doped layer covering the pit may not be able to effectively fill the bottom of the pit, and the pit penetrating too deeply into the semiconductor substrate may also lead to defects. In some cases, the ratio of the depth of the lower sidewall to the depth of the upper sidewall of the pit in the thickness direction of the semiconductor substrate is greater than 2 and less than 5. This setting can accommodate batteries with thinner doped layers, ensuring that the lower part of the pit has sufficient depth to effectively trap light.

[0116] In some embodiments, as shown in FIG1, 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.

[0117] In the back contact battery 100 of this application 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 mating 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 mating surface 400 and the side wall mating surface 604 at the pit 601 can work together. A portion of the leakage current collected by the side wall mating surface 604 at the pit 601 can be dispersed to the side mating surface 400 of the stacked structure 600, accelerating the transmission speed of the leakage current and further improving the hot spot prevention effect.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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 between the spacer region 190 and the first doped region 191, or the junction between 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 between the spacer region 190 and the first doped region 191, or the junction between 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.

[0122] 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 be in direct contact 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 be indirectly contacted 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.

[0123] The back contact battery 100 of this application embodiment will be described below with reference to FIG9.

[0124] In Figure 9, the first doped layer 200 includes a main body portion 204, and the second doped layer 300 includes a main body portion 304. 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, in Figure 9, the main body portion 204 includes strip-shaped portions 201 and connecting portions 202, wherein the connecting portions 202 connect multiple strip-shaped portions 201. The second doped layer 300 includes strip-shaped portions 301 and connecting portions 302, wherein the connecting portions 302 connect multiple strip-shaped portions 301. 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.

[0125] 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.

[0126] 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.

[0127] Similar to Figure 8, the extension 203 of the first doped layer in Figure 9 is typically formed integrally 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.

[0128] Thus, in the aforementioned case where a portion of the second doped layer 300 overlaps a portion of the first doped layer 200 to form a stacked structure 600, "a portion of the second doped layer" can be a part of the strip-shaped portion 301 of the second doped layer, or all or a part of the connecting portion 302 of the second doped layer, or all or a part of the extension portion 303 of the second doped layer. Similarly, "a portion of the first doped layer" can be a part of the strip-shaped portion 201 of the first doped layer, or all or a part of the connecting portion 202 of the first doped layer, or all or a 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.

[0129] The stacked structure 600 can be formed 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 to form a stacked structure; 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 to form a stacked structure; 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 to form a stacked structure; 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 to form a stacked structure; 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 to form a stacked structure.

[0130] For example, in Figure 9, 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 such that at the first doped region 191, 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) is formed 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 a portion of the strip portion 201 of the first doped layer.

[0131] The specific structure of the spacer region 190, the number of pits 601, the shape of the pits 601, the formation position 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 are similar to the back contact battery 100 in FIG8. Only some features are shown below.

[0132] 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.

[0133] 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.

[0134] In some embodiments, referring to FIG1, 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.

[0135] 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.

[0136] In some embodiments, the conductive doped block 602 is partially electrically connected to the enclosing recess 601 of the first doped layer 200 in the stacked structure 600, forming a sidewall mating surface 604. The effect is similar to that described above and will not be repeated here.

[0137] 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.

[0138] In some embodiments, the dielectric layer 603 is interrupted in a partial region, thereby forming a leakage current path 630. As shown in FIG3, the dielectric layer 603 may be interrupted at the leakage current path 630. The effect is similar to that described above and will not be repeated here.

[0139] In other embodiments, as shown in FIG4, 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.

[0140] In some embodiments, as shown in FIG1, 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.

[0141] Similar to the previous description, the location of the side mating surface 400 can be at the following locations: 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 boundary between the spacer region 190 and the first doped region 191 (also referred to as the boundary between the spacer region 190 and the strip portion 201 of the first doped layer), the boundary between the spacer region 190 and the second doped region 192 (also referred to as the boundary between the spacer region 190 and the strip portion 301 of the second doped layer), the boundary between the spacer region 190 and the third doped region 193 (also referred to as the boundary between the spacer region 190 and the extension portion 203 of the first doped layer), the boundary between the spacer region 190 and the fourth doped region 194 (also referred to as the boundary between the spacer region 190 and the connecting portion 302 of the second doped layer), etc., which will not be elaborated here.

[0142] The overall structure of the back contact battery 100 of this application embodiment will be described below with reference to Figures 1 and 2.

[0143] As shown in Figures 1 and 2, 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 in the stacked structure 600. The longitudinal cross-sectional shape of the pit 601 is an inverted triangle shape.

[0144] The back contact battery 100 shown in Figure 1 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. The surface passivation layer 140 of the back contact battery 100 may be located between the first doped layer 200 and the electrode structure or between the second doped layer 300 and the electrode structure. A portion of the electrode structure may penetrate the surface passivation layer 140 to contact the first doped layer 200 or the second doped layer 300 to form an electrical connection.

[0145] 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 application 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 (multiple current collector electrodes include multiple first electrodes 121 and multiple second electrodes 122 of different polarities). 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 application 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.

[0146] The materials of each layer and electrode of the back contact battery 100 in this application embodiment 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.

[0147] The semiconductor substrate can be a silicon substrate. The silicon substrate can be N-type or P-type silicon, and its thickness can be 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.

[0148] 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.

[0149] The first and second dielectric layers can be one or more of oxides, nitrides, oxynitrides, halides, and carbides; alternatively, the first and second dielectric layers can be one or more of 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.

[0150] The insulating layer can be one or more of oxides, nitrides, oxynitrides, halides, and carbides, or it can be one or more of silicon. 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.

[0151] The surface passivation layer can be one or more of oxides, nitrides, oxynitrides, halides, and carbides, or it can be one or more of silicon. 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.

[0152] The method for preparing the back contact battery 100 in this embodiment can refer to any existing method that can be used to prepare the back contact battery 100, and is not limited here.

[0153] For the fabrication of pits, existing laser etching (laser conditions can refer to the parameters for etching pits on semiconductor materials in existing technologies) or chemical etching (e.g., etching with chemical reagents such as acids and alkalis that can react with semiconductor materials) can be used. The laser intensity, laser spot shape and size, laser treatment time and number of passes are selected based on the desired pit size, depth, and shape; the type and concentration of the chemical reagents, treatment time, and treatment range are also selected based on the desired pit size, depth, and shape. Furthermore, the prismatic structure within the pit can be obtained by chemically treating it with alkaline solutions or other chemical reagents after laser etching or chemical etching. It is understood that the chemical treatment step can utilize the wet etching step (such as alkaline treatment) in existing processes to achieve the fabrication of the prismatic structure.

[0154] Regarding the fabrication sequence of the pit and the doped layer, one approach is to first fabricate the lower part of the pit, i.e., form the lower part of the pit at the location where the pit is planned on the semiconductor substrate, then deposit a doped layer of one conductivity type (e.g., the first doped layer 200), and fabricate a through-hole in this doped layer at the location corresponding to the lower part of the pit, forming the upper part of the pit. Then, deposit a doped layer of another conductivity type (e.g., the second doped layer 300) to cover the pit. Alternatively, one approach is to first deposit a doped layer of one conductivity type (e.g., the first doped layer 200) on the semiconductor substrate, form a pit penetrating this doped layer and extending into the semiconductor substrate at the location where the pit is planned, and then deposit a doped layer of another conductivity type (e.g., the second doped layer 300) to cover the pit. If the pit has a prismatic structure, the prismatic structure fabrication step is performed before the doped layer of another conductivity type (e.g., the second doped layer 300) covers the pit.

[0155] Implementation Plan B

[0156] This application embodiment also provides a back contact battery 100, wherein, as shown in FIG11, 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; wherein, a first portion 351 of the second doped layer overlaps on a portion of the first doped layer to form a stacked structure 600; and wherein, a portion of the second portion 352 of the second doped layer 300 near the stacked structure 600 is raised in the direction away from the stacked structure 600 to form a raised portion 361.

[0157] In the back contact battery 100 of this application embodiment, by overlapping the first portion 351 of the second doped layer with a portion of the first doped layer to form a stacked structure 600, a built-in diode with a low reverse breakdown voltage can be formed at the electrical connection between the first doped layer 200 and the second doped layer 300. This facilitates a lower reverse breakdown voltage when the back contact battery 100 is shielded, reducing the risk of hot spots in the back contact battery 100. By tilting a portion of the second portion 352 of the second doped layer 300 near the stacked structure 600 away from the stacked structure 600 to form a tilted portion 361, a gap can be formed between the tilted portion 361 and the stacked structure 600. The existence of the gap can separate a portion of the first doped layer 200 and the second portion 352 of the second doped layer 300 in the stacked structure 600, thereby preventing the formation of a leakage area at the gap, dispersing the leakage points, and avoiding local overheating. For example, an air gap 363 can be formed between the raised portion 361 and the stacked structure 600. The presence of the air gap 363 can separate a portion of the first doped layer 200 and the second portion 352 of the second doped layer 300 in the stacked structure 600. Alternatively, a film gap can also be formed between the raised portion 361 and the stacked structure 600, that is, the presence of an insulating or semi-insulating film can separate a portion of the first doped layer 200 and the second portion 352 of the second doped layer 300 in the stacked structure 600. The presence of the raised portion 361 can reduce the proportion of leakage contact area, thereby minimizing the loss of battery conversion efficiency caused by PN region contact while improving the hot spot effect. At the same time, the air gap 363 can form physical insulation. Compared with a dielectric layer with a certain degree of conductivity (such as an interface passivation layer), the air gap 363 has a stronger insulation effect and higher reliability, which can enhance the local insulation effect and facilitate the forward power generation of the back contact battery 100. Therefore, by adjusting the total number and size of the raised portions 361, a balance can be achieved between improving the hot spot effect and ensuring photoelectric conversion efficiency.

[0158] This application also provides a photovoltaic module (not shown in the figures), which includes a battery string formed by electrical connections of the aforementioned back contact battery 100 and an encapsulation layer covering the surface of the battery string. This photovoltaic module has effects similar to those of the aforementioned back contact battery 100.

[0159] In Embodiment A, the back contact battery 100 has been described in detail, and the same content will not be repeated here. Instead, the different features of the back contact battery 100 of this application embodiment will be described in more detail with reference to the accompanying drawings. Embodiment B can be understood by referring to the content of Embodiment A, and the features in Embodiment A can be directly combined with the features in Embodiment B.

[0160] It is understood that, similar to the description in Embodiment A, in this Embodiment B, "first doped layer" and "second doped layer" are only for ease of description, and the first doped layer 200 and the second doped layer 300 can be interchanged in terms of function and placement. Alternatively, 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; wherein, a first portion of the first doped layer 200 overlaps a portion of the second doped layer 300 to form a stacked structure 600; and wherein, a portion of the second portion of the first doped layer 200 near the stacked structure 600 is raised in the direction away from the stacked structure 600 to form a raised portion.

[0161] In the aforementioned stacked structure 600 formed by overlapping a portion of the first doped layer with the first doped layer, the "first portion of the second doped layer" can be a part 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 part of the main body 204 of the first doped layer, or all or part of the extension 203 of the first doped layer. The "second portion of the second doped layer" is a portion that depends on the "first portion of the second doped layer". Specifically, when the first portion 351 of the second doped layer is a part of the main body 304 of the second doped layer, the second portion 352 of the second doped layer is a part of the main body 304 of the second doped layer. When the first portion 351 of the second doped layer is a part of the extension 303 of the second doped layer, the second portion 352 of the second doped layer is also a part of the extension 303 of the second doped layer.

[0162] Regarding the specific structure of the spacing region 190, in this embodiment B, in the back contact battery 100 of this application embodiment, the spacing region 190 may be a spacing 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.

[0163] Similar to the description in Embodiment A, 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, the first portion 351 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 first doped layer 200.

[0164] The location of the layered structure 600 can be referred to the description in Implementation Scheme A, and will not be repeated here.

[0165] In some embodiments, as shown in FIG15, the second doped layer 300 further includes an extension 303 of the second doped layer, which extends across the spacer region 190 and over a portion of the first doped layer 200 to form a stacked structure 600, wherein a first portion 351 and a second portion 352 of the second doped layer 300 are portions of the extension 303 of the second doped layer. FIG15 shows the extension 303 of the second doped layer extending across the spacer region 190 and over a portion of the body portion 204 of the first doped layer. In this case, the second portion 352 of the second doped layer 300 near the stacked structure 600 is the portion of the extension 303 of the second doped layer located between the dashed line and a side mating surface 400 in FIG15. Because the second portion 352 of the second doped layer 300 is raised upwards to overlap the body portion 204 of the first doped layer, a portion of the second portion 352 warps away from the stacked structure 600, forming a warped portion 361.

[0166] Referring to Figures 11 and 15, the extension 303 of the second doped layer can be roughly divided into three parts: the first part 351 is the portion of the extension 303 of the second doped layer that forms the stacked structure 600; the third part 353 is the portion of the extension 303 of the second doped layer that adheres to the semiconductor substrate 101; and the second part 352 is the bridge portion of the extension 303 of the second doped layer located between the first part 351 and the third part 353. A portion of the second part 352 is raised away from the stacked structure 600, forming a raised portion 361. Figure 19 shows an SEM image of the back contact cell 100 with the raised portion 361.

[0167] It is understood that the three parts of the extension 303 of the second doped layer, namely the first part 351, the second part 352, and the third part 353, can be formed integrally or separately. Adjacent parts are electrically connected, structurally connected or partially stacked, and can be the same or different in terms of material and conductivity type.

[0168] In other embodiments, as shown in FIG14, the first doped layer 200 further includes an extension 203 of the first doped layer, and the second doped layer 300 further includes an extension 303 of the second doped layer. The extension 303 of the second doped layer overlaps the extension 203 of the first doped layer in the spacer region 190 to form a stacked structure 600, wherein the first portion 351 and the second portion 352 of the second doped layer 300 are part of the extension 303 of the second doped layer. Specifically, the first portion 351 of the second doped layer 300 is the portion of the extension 303 of the second doped layer that forms the stacked structure 600, and the second portion 352 is the bridge portion of the extension 303 of the second doped layer near the first portion 151.

[0169] In some embodiments, as shown in FIG16, the first doped layer 200 further includes an extension 203 of the first doped layer that extends across the spacer region 190 and below the body portion 304 of the second doped layer to form a stacked structure 600, wherein a first portion 351 of the second doped layer 300 is a part of the body portion 304 of the second doped layer. FIG16 shows the extension 203 of the first doped layer extending across the spacer region 190 and below the body portion 304 of the second doped layer. In this case, a second portion 352 of the second doped layer 300 near the stacked structure 600 is the portion of the body portion 304 of the second doped layer located between the dashed line and the plurality of side mating surfaces 400 in FIG16. This second portion 352 of the second doped layer 300 is lifted upwards because the end of the extension 203 of the first doped layer is inserted below the first portion 351 of the second doped layer 300, causing a portion of the second portion 352 to warp away from the stacked structure 600, forming a warped portion 361.

[0170] In Figure 16, the main body 304 of the second doped layer can be roughly divided into three parts: the first part 351 is the portion of the main body 304 of the second doped layer that forms the stacked structure 600; the third part 353 is the portion of the main body 304 of the second doped layer that adheres to the semiconductor substrate 101; and the second part 352 is the bridge portion of the main body 304 of the second doped layer located between the first part 351 and the third part 353. A portion of the second part 352 is raised away from the stacked structure 600, forming a raised portion 361. The first part 351, the second part 352, and the third part 353 of the main body 304 of the second doped layer can be formed integrally or separately, similar to the first part 351, the second part 352, and the third part 353 of the extension 303 of the second doped layer, and will not be described in detail here.

[0171] In some embodiments, in the back contact battery 100 of this application embodiment, another portion of the second portion 352 of the second doped layer 300 is closely attached to the stacked structure 600 to form an adhesion portion 362; wherein, in the third direction, a plurality of raised portions 361 and a plurality of adhesion portions 362 alternate; the third direction is parallel to the extension direction of the side of the first doped layer 200 in the stacked structure 600 opposite to the second portion 352 of the second doped layer 300. By alternating the plurality of raised portions 361 and a plurality of adhesion portions 362, leakage points can be further dispersed, avoiding local overheating; the presence of the adhesion portion 362 can increase the proportion of leakage contact area, thereby, by adjusting the total number, size, arrangement, etc. of the plurality of raised portions 361 and the plurality of adhesion portions 362, a balance can be achieved between improving the hot spot effect and ensuring photoelectric conversion efficiency.

[0172] The "third direction" extends parallel to the side of the first doped layer 200 in the stacked structure 600 opposite to the second portion 352 of the second doped layer 300. In the back contact battery 100 of this embodiment, the first doped layer 200 in the stacked structure 600 is electrically connected to the second portion 352 of the second doped layer 300, and the side of the first doped layer 200 in the stacked structure 600 opposite to the second portion 352 of the second doped layer 300 forms a side mating surface 400. The extension direction of the side of the first doped layer 200 in the stacked structure 600 opposite to the second portion 352 of the second doped layer 300 is also the extension direction of the side mating surface 400. FIG13a) shows the bent structure 500 of the side mating surface 400 in a top view, and FIG13b) shows a plurality of raised portions 361 and a plurality of mating portions 362 alternating in the third direction in a side view. For example, in the example shown in Figure 15, there is one side mating surface 400. In this case, the extension direction and the corresponding third direction of the side mating surface 400 are the up and down directions in Figure 15. In the example shown in Figure 16, there are three side mating surfaces 400. Each side mating surface 400 has its own extension direction and third direction. Specifically, the extension direction and the corresponding third direction of the first side mating surface 401 and the second side mating surface 402 are the left and right directions in Figure 16, while the extension direction and the corresponding third direction of the third side mating surface 403 located in the middle are the up and down directions in Figure 16.

[0173] For the formation location of the side mating surface 400 and the contact method between a portion of the first doped layer 200 and a portion of the second doped layer 300, please refer to the description in Implementation Scheme A, which will not be repeated here.

[0174] In some embodiments, in the back contact battery 100 of this application, the side contact surface 400 has a bent structure 500; in other words, the side contact surface 400 is not a flat surface. When multiple side contact surfaces exist, one or more of them may have a bent structure 500. Compared to a planar contact surface, a side contact surface 400 with a bent structure 500 can increase the leakage current channel contact area of ​​a single side contact surface 400, effectively reducing the total number of anti-hot spot structures, and minimizing battery conversion efficiency loss due to PN region contact while improving the hot spot effect.

[0175] Specifically, in a direction parallel to the backlight surface 112, a single side mating surface 400 has a bending unfolded length L (not shown in the figure) and an end straight line length D (see Figure 18), where L > 1.001D. By limiting the relationship between the bending unfolded length L and the end straight line length D to L > 1.001D, it can be ensured that the side mating surface 400 forms a bend.

[0176] In some embodiments, under a 10-micron step measurement condition, L ≥ 1.05D, for example, L can be 1.05D, 1.08D, 1.10D, 1.20D, etc. By ensuring L ≥ 1.05D, it can be further ensured that the side mating surface 400 has a bent structure. Considering that in practical applications, it may be difficult or too complicated to measure a complete side mating surface 400, the relationship between L and D can be determined using a 10-micron step measurement condition. The 10-micron step measurement condition involves selecting one or more local segments with a straight length of 10 microns from the entire side mating surface 400, where the end straight length D of the one or more local segments is 10 microns, and measuring the bent unfolded length L of the bent structure of the one or more local segments. The relationship between L and D is thus obtained directly or by averaging.

[0177] In a preferred embodiment, under a 1-micron step measurement condition, L ≥ 1.2D, for example, L can be 1.2D, 1.4D, 1.5D, 1.8D, 5D, etc. By ensuring L ≥ 1.2D, the bent structure of the side contact surface 400 can be ensured, which can significantly increase the leakage channel contact area of ​​a single side contact surface 400, effectively preventing the back contact cell 100 from burning out due to local heat concentration, effectively reducing the hot spot risk of the back contact cell 100 and the photovoltaic module including the back contact cell 100, and also effectively reducing the total number of side contact surfaces 400. Typically, L ≤ 800D, for example, L can be 800D, 600D, 200D, 50D, 10D, etc. When L exceeds the aforementioned range, it will lead to excessive etching difficulty and affect production efficiency.

[0178] The value of D can range from 10 to 3000 micrometers. For example, D can be 10 micrometers, 100 micrometers, 500 micrometers, 1000 micrometers, 1500 micrometers, 2500 micrometers, 3000 micrometers, etc.

[0179] The value of L can range from 50 to 8000 micrometers. For example, L can be 50 micrometers, 150 micrometers, 650 micrometers, 1500 micrometers, 2500 micrometers, 3000 micrometers, 5000 micrometers, 8000 micrometers, etc.

[0180] Regarding the "direction parallel to the backlight surface," taking the backlight surface 112 of the semiconductor substrate 101 on the upward side as an example, such as the upper part in Figure 17, the direction of the backlight surface 112 can be considered to be generally horizontal. The side mating surface 400 is a surface perpendicular to the horizontal direction or at a certain angle to the horizontal direction. This surface has two first vertical sides perpendicular to the horizontal direction or at a certain angle to the horizontal direction, and two second horizontal sides generally parallel to the horizontal direction. In this article, "direction parallel to the backlight surface 112" refers to the extension direction of the second horizontal side, also called "extension direction of the side mating surface" or "extension direction of the bent structure." Thus, the bending unfolded length L and the end straight line length D are respectively discussing the bending unfolded length and end straight line length of the second horizontal side. For example, in the example shown in Figure 16, there are three side mating surfaces 400. Each side mating surface 400 has its own direction parallel to the backlight surface 112, its own extension direction, and its own extension direction of the bent structure 500. Specifically, the direction parallel to the backlight surface 112, the extension direction of the side mating surface, and the extension direction of the bent structure 500 of the first side mating surface 401 and the second side mating surface 402 are the left-right directions in Figure 16, while the direction parallel to the backlight surface 112, the extension direction of the side mating surface, and the extension direction of the bent structure 500 of the third side mating surface 403 are the up-down directions in Figure 16.

[0181] The bending structure 500 can be any structure that makes the side mating surface 400 no longer a flat surface. An exemplary configuration of the bending structure 500 will be described in detail below with reference to the accompanying drawings.

[0182] In some embodiments, the bending structure 500 includes a plurality of docking sections 510 that are bent and connected in a direction parallel to the backlight surface 112, as shown in Figures 13a) and 18. By configuring the bending structure 500 to include a plurality of docking sections 510 that are bent and connected, it can be ensured that the presence of the bending structure 500 can significantly increase the leakage current channel contact area of ​​a single side docking surface 400, effectively preventing local overheating of the back contact battery 100 and effectively reducing the total number of side docking surfaces 400.

[0183] Referring again to Figures 13a) and 18, the mating section 510 contains a plurality of protruding portions 511 protruding toward the second portion 352 of the second doped layer 300 and a plurality of recessed portions 512 recessed away from the second portion 352 of the second doped layer 300. In some embodiments, a raised portion 361 may be formed at a position corresponding to the protruding portion 511 of the second portion 352 of the second doped layer 300, as marked 371 in Figure 13; or, a raised portion 361 may be formed at a position corresponding to the recessed portion 512 of the second portion 352 of the second doped layer 300, as marked 372 in Figure 13; or, a raised portion 361 may be formed at a position corresponding to the recessed portion 512 adjacent to the protruding portion 511 of the second portion 352 of the second doped layer 300, as marked 373 in Figure 13. By aligning the position of the raised portion 361 with the protruding portion 511, the recessed portion 512, and the recessed portion 512 adjacent to the protruding portion 511 in the mating section, it is ensured that the raised portion 361 is dispersed, thereby dispersing the mating portion 362, which further facilitates the dispersion of leakage points.

[0184] In some embodiments, an air gap 363 is defined between the raised portion 361, the first doped layer 200 in the stacked structure 600, and the semiconductor substrate 101, as shown in FIG11. The presence of the air gap 363 can separate a portion of the first doped layer 200 and the second portion 352 of the second doped layer 300 in the stacked structure 600, thereby preventing the formation of a leakage area at the air gap 363, dispersing leakage points, and avoiding local overheating; the air gap 363 can form physical insulation, and compared with a dielectric layer with a certain conductivity (such as an interface passivation layer), the air gap 363 has a stronger insulation effect and higher reliability, which can enhance the local insulation effect, further reduce contact recombination, and facilitate the forward power generation of the back contact battery 100.

[0185] The back contact battery 100 also includes a surface passivation layer 140, which covers the first doped layer 200, the second doped layer 300, and the stacked structure 600. The surface passivation layer 140 extends into the air gap 363 at the raised portion 361, thereby filling part or all of the air gap 363, as shown in FIG14. FIG14 shows the surface passivation layer 140, which extends into the air gap 363 at the raised portion 361, thereby filling part of the air gap 363. When the surface passivation layer 140 fills part of the air gap 363, the raised portion 361 is not only insulated by the air gap 363 but also separated by the surface passivation layer 140, which is beneficial for the forward power generation of the back contact battery 100.

[0186] The back contact battery 100 was described in Implementation Scheme A with reference to Figures 8 and 9, and will not be repeated here. The first portion 351 of the aforementioned second doped layer overlaps over a portion of the first doped layer to form a stacked structure 600. The "first portion of the second doped layer" can be a part of the strip-shaped portion 301 of the second doped layer, 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. The "part of the first doped layer" can be a part of the strip-shaped portion 201 of the first doped layer, 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. The "second portion of the second doped layer" depends on... The term "first portion of the second doped layer" refers to a portion of the second doped layer where, when the first portion 351 of the second doped layer is part of the main body portion 304 of the second doped layer, the second portion 352 of the second doped layer is also part of the main body portion 304 of the second doped layer; when the first portion 351 of the second doped layer is part of the connecting portion 302 of the second doped layer, the second portion 352 of the second doped layer is also part of the connecting portion 302 of the second doped layer; and when the first portion 351 of the second doped layer is part of the extension portion 303 of the second doped layer, the second portion 352 of the second doped layer is also part of the extension portion 303 of the second 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 in an adjacent position to form a stacked structure 600.

[0187] The location of the stacked structure 600 can be referred to the description in Implementation Scheme A above, and will not be repeated here.

[0188] In some embodiments, another portion of the second portion 352 of the second doped layer 300 is closely attached to the stacked structure 600 to form an adhesion portion 362; wherein, in the third direction, a plurality of raised portions 361 and a plurality of adhesion portions 362 alternate; the third direction extends parallel to the side of the first doped layer 200 in the stacked structure 600 opposite to the second portion 352 of the second doped layer 300. The effect is similar to that described above and will not be repeated here.

[0189] In some embodiments, the first doped layer 200 in the stacked structure 600 is electrically connected to the second portion 352 of the second doped layer 300, and the side of the first doped layer 200 in the stacked structure 600 opposite to the second portion 352 of the second doped layer 300 forms a side mating surface 400, wherein the side mating surface 400 has a bent structure 500. The effect is similar to that described above and will not be repeated here.

[0190] As for the location of the side mating surface 400, please refer to the description in Implementation Scheme A, which will not be repeated here.

[0191] In some embodiments, the raised portion 361, the first doped layer 200 in the stacked structure 600, and the semiconductor substrate 101 define an air gap 363 therebetween. The effect is similar to that described above and will not be repeated here.

[0192] In some embodiments, the back contact battery 100 further includes a surface passivation layer 140, which covers the first doped layer 200, the second doped layer 300, and the stacked structure 600. The surface passivation layer 140 extends into the air gap 363 at the raised portion 361, thereby filling part or all of the air gap 363. The effect is similar to that described above and will not be repeated here.

[0193] The overall structure of the back contact battery 100 according to an embodiment of this application will be described below with reference to FIG17.

[0194] Figure 17 is similar to Figure 1, except that the first portion 351 of the second doped layer 300 overlaps a portion of the first doped layer 200 to form a stacked structure 600; and a portion of the second portion 352 of the second doped layer 300 near the stacked structure 600 tilts away from the stacked structure 600, forming a tilted portion 361. Specifically, the extension portion 303 of the second doped layer extends across the spacer region and over the main body portion 204 of the first doped layer to form the stacked structure 600; and a portion of the second portion 352 of the extension portion 303 of the second doped layer near the stacked structure 600 tilts away from the stacked structure 600, forming a tilted portion 361. A surface passivation layer 140 covers the first doped layer 200, the second doped layer 300, and the stacked structure 600, wherein the surface passivation layer 140 extends into the air gap 363 at the tilted portion 361, thereby filling the entire air gap 363.

[0195] 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 brief description of the materials of each layer in embodiment A can be referred to, and will not be repeated here.

[0196] The formation of raised portions can be achieved by adjusting process conditions such as temperature, reaction time, type of reaction solution, and concentration of reaction solution during battery fabrication. Alternatively, it can be achieved by pre-embedding a film layer. For example, a suitable additional film layer can be pre-embedded between a portion of the first doped layer and the second portion of the second doped layer in a stacked structure, and then the raised portion can be obtained by completely or partially dissolving the film layer. Another method is to set a concave-convex structure parallel to the surface of the semiconductor substrate on the sidewall of the spacer region of the semiconductor substrate. During the fabrication of the doped layer, the different stresses at the protruding and recessed parts can cause the doped layer to be raised or broken, thus forming raised portions.

[0197] Implementation Plan C

[0198] The preceding sections, Implementation Scheme A and Implementation Scheme B, described some features of the back contact battery, respectively. It should be understood that Implementation Scheme A and Implementation Scheme B can be implemented independently, and some or all features of Implementation Scheme A can be used in combination with some or all features of Implementation Scheme B.

[0199] For example, some features related to the pits at the stacked structure in implementation scheme A and some features related to the raised portion in implementation scheme B can be implemented individually or in combination, provided that such combinations are technically feasible.

[0200] The positions of the recesses and raised portions can be set as needed. For example, if the recesses and raised portions are set correspondingly, during normal operation of the back-contact battery, carrier recombination will occur because the recesses contain recombination centers of two types of conductive doped layers, reducing battery efficiency. However, by placing the raised portions near the recesses, the accumulation of carriers near the recesses can be hindered to some extent, thus preventing a decrease in battery efficiency and achieving a balance between preserving the hot spot prevention effect and maintaining battery efficiency. Alternatively, if the recesses and raised portions are staggered, this is often used in batteries with a high demand for hot spot prevention. In this scheme, the raised portions are farther from the recesses, and the raised portions do not hinder the accumulation of carriers near the recesses. In the event of a hot spot, leakage current can be consumed or discharged more quickly.

[0201] In addition, the number and size of the pits and the number and size of the raised parts can be adjusted according to the overall configuration requirements of the back contact battery for hot spot prevention and battery power generation efficiency. It is understandable that a greater number and larger size of pits results in more leakage structures, a larger leakage area, and a lower risk of hot spots, but also a decrease in battery efficiency. Conversely, a greater number and larger area of ​​raised parts results in a smaller leakage area, which improves battery efficiency to some extent, but reduces the effectiveness of hot spot prevention. Therefore, in practical applications, a combination of these two methods can be used to suit different scenarios and needs.

[0202] The method for fabricating the back contact battery 100 in this application embodiment can refer to any method in the prior art that can be used to fabricate the back contact battery 100, and is not limited thereto. For the pits and related structures, they can be obtained using existing laser etching or other methods, as described in embodiment A. For the formation of the raised portion, refer to the description in embodiment B.

[0203] Although the solutions of this application are described in the claims, it should be understood that the solutions of this application may be described alternatively with reference to the following embodiments:

[0204] Example 1. The back contact battery includes: a semiconductor substrate, a first doped layer and a second doped layer; the main body of the first doped layer and the main body of the second doped layer are alternately distributed on the back side of the semiconductor substrate, and the first doped layer and the second doped layer have opposite conductivity types;

[0205] A first portion of the second doped layer overlaps a portion of the first doped layer to form a stacked structure; and wherein a portion of the second doped layer near the stacked structure is raised in a direction away from the stacked structure to form a raised portion.

[0206] Example 2. The back contact battery according to Example 1, wherein,

[0207] Another portion of the second part of the second doped layer is closely attached to the stacked structure to form a bonding portion;

[0208] In the third direction, multiple raised portions and multiple adhered portions alternate; the third direction extends parallel to the side of the first doped layer in the stacked structure, opposite to the second part of the second doped layer.

[0209] Example 3. The back contact battery according to Example 1, wherein,

[0210] In the stacked structure, the first doped layer and the second part of the second doped layer are electrically connected, and the side of the first doped layer opposite to the second part of the second doped layer in the stacked structure forms a side mating surface, wherein the side mating surface has a bent structure.

[0211] Example 4. The back contact battery according to Example 3, wherein,

[0212] The bent structure comprises multiple docking sections that are bent and connected in a direction parallel to the backlight surface.

[0213] Example 5. The back contact battery according to Example 4, wherein,

[0214] The docking section contains multiple protruding portions that protrude toward the second part of the second doped layer and multiple recessed portions that are recessed away from the second part of the second doped layer.

[0215] Example 6. The back contact battery according to Example 5, wherein,

[0216] The raised portion is formed at the position corresponding to the protruding portion in the second part of the second doped layer; or

[0217] The raised portion is formed at a position corresponding to the recessed portion in the second part of the second doped layer; or

[0218] The raised portion is formed at a position in the second part of the second doped layer corresponding to the recessed portion adjacent to the raised portion.

[0219] Example 7. The back contact battery according to Example 1, wherein,

[0220] The raised portion, the first doped layer in the stacked structure, and the semiconductor substrate define an air gap therebetween.

[0221] Example 8. The back contact battery according to Example 7, wherein,

[0222] The back contact battery also includes a surface passivation layer, which covers a first doped layer, a second doped layer, and a stacked structure. The surface passivation layer extends into the air gap at the raised portion, thereby filling part or all of the air gap.

[0223] Example 9. The back contact battery according to Example 1, wherein,

[0224] There is a gap region between the main body portion of the first doped layer and the main body portion of the second doped layer;

[0225] The second doped layer also includes an extension of the second doped layer that extends across the spacer region and over a portion of the first doped layer to form a stacked structure, wherein the first portion and the second portion of the second doped layer are part of the extension of the second doped layer.

[0226] Example 10. The back contact battery according to Example 1, wherein,

[0227] There is a gap region between the main body portion of the first doped layer and the main body portion of the second doped layer;

[0228] The first doped layer further includes an extension of the first doped layer, and the second doped layer further includes an extension of the second doped layer. The extension of the second doped layer overlaps the extension of the first doped layer in the spacer region to form a stacked structure, wherein the first portion and the second portion of the second doped layer are part of the extension of the second doped layer.

[0229] Example 11. The back contact battery according to Example 1, wherein,

[0230] There is a gap region between the main body portion of the first doped layer and the main body portion of the second doped layer;

[0231] The first doped layer also includes an extension of the first doped layer that extends across the spacer region and extends below the main body of the second doped layer to form a stacked structure, wherein the first portion of the second doped layer is part of the main body of the second doped layer.

[0232] Example 12: Photovoltaic modules include:

[0233] Battery string, the battery string being formed by the electrical connection of multiple back-contact batteries as described in any of Examples 1-11; and

[0234] Encapsulation layer, which covers the surface of the battery string.

[0235] 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.

[0236] 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 this application. 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.

[0237] The embodiments of this application have been described in detail above. However, aspects of this application are not limited to the embodiments described above. Various modifications and substitutions can be applied to the above embodiments without departing from the scope of this application.

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