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 body portions of the first doped layer and main body portions of the second doped layer are alternately arranged on a non-light receiving surface side of the semiconductor substrate, and the first doped layer and the second doped layer have opposite conductivity types. A portion of the first doped layer is electrically connected to a portion of the second doped layer and form a side abutting surface. The side abutting surface has a first bent structure. The present application further provides a photovoltaic module. In the back-contact cell of the present application, the side abutting surface having the first bent structure can increase the contact area of a leakage current path of a single hot-spot mitigation structure.

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 battery 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, comprising: 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 first doped layer and a portion of the second doped layer are electrically connected (also called electrically connected) and form a side mating surface, and the side mating surface has a first bending structure.

[0007] In the back contact battery of this application, by electrically connecting a portion of the first doped layer and a portion of the second doped layer to form a side mating surface, a built-in diode with a low reverse breakdown voltage can be formed at the electrical connection between the first doped layer and the second doped layer. This is beneficial for the back contact battery to have a low reverse breakdown voltage when it is shielded, thereby reducing the risk of hot spots. At the same time, compared with the mating surface with a planar structure, the side mating surface with a first bending structure can increase the leakage channel contact area of ​​a single anti-hot spot structure, effectively reducing the total number of anti-hot spot structures. This improves the hot spot effect while minimizing the battery conversion efficiency loss caused by PN region contact.

[0008] Optionally, the first bending structure includes a plurality of first mating sections that are bent and connected in a direction parallel to the backlight surface.

[0009] Optionally, at least one of the plurality of first docking sections has a second bending structure.

[0010] Optionally, the second bending structure includes a plurality of second mating sections that are bent and connected in a direction parallel to the backlight surface.

[0011] Optionally, a first portion of the first doped layer and a second portion of the second doped layer are electrically connected and form a first side mating surface;

[0012] The second portion of the second doped layer is also electrically connected to the semiconductor substrate and forms a second side mating surface;

[0013] The first side mating surface and the second side mating surface both have a first bending structure, and the second side mating surface also has a second bending structure.

[0014] Optionally, each first docking segment has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1;

[0015] Each second docking section has a second protrusion, and the distance between the maximum points of two adjacent second protrusions is T2;

[0016] Where T1 > T2.

[0017] Optionally, T1 is 5 to 100 times T2.

[0018] Optionally, in a direction perpendicular to the extension direction of the first bending structure, the first bending structure has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1;

[0019] In a direction perpendicular to the extension direction of the second bending structure, the second bending structure has a second maximum point and a second minimum point, and the distance between the second maximum point and the second minimum point is δ2.

[0020] Among them, δ1>δ2.

[0021] Optionally, the value of T1 ranges from 0.01 to 500 micrometers;

[0022] The value of T2 ranges from 0.001 to 50 micrometers;

[0023] The value of δ1 ranges from 0.001 to 200 micrometers;

[0024] The value of δ2 ranges from 0.0001 to 20 micrometers.

[0025] Optionally, each first docking segment has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1;

[0026] In a direction perpendicular to the extension direction of the first bending structure, the first bending structure has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1;

[0027] Where 0.00005≤T1 / δ1≤500000.

[0028] Optionally, in a direction parallel to the backlight surface, a single side mating surface has a bending unfolding length L and an end straight line length D, where L > 1.001D.

[0029] Optionally, each first docking segment has a first protrusion, which has one or more of the following shapes: arc-shaped, square-shaped, trapezoidal, triangular, or irregular.

[0030] Optionally, a portion of the first doped layer and a portion of the second doped layer have a conductive connection structure, wherein a single conductive connection structure includes at least two side mating surfaces.

[0031] In the back contact battery of this application, by setting a conductive connection structure between a portion of the first doped layer and a portion of the second doped layer, a built-in diode with a low reverse breakdown voltage can be formed at the electrical connection between the first doped layer and the second doped layer. This is beneficial for the back contact battery to have a low reverse breakdown voltage when it is shaded, thereby reducing the risk of hot spots. At the same time, by setting a single conductive connection structure to include at least two side mating surfaces, when the size of a single conductive connection structure is fixed, the contact area of ​​the leakage channel of the single conductive connection structure can be increased to enhance the hot spot prevention function. Meanwhile, by dispersing the electrical connection points to at least two sides, the heat points can be dispersed, avoiding local overheating and improving the hot spot effect.

[0032] 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;

[0033] 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 extensions of the first doped layer and the second doped layer are electrically connected at the interval region to form a conductive connection structure.

[0034] Optionally, the extensions of the first doped layer and the extensions of the second doped layer are staggered.

[0035] Optionally, the extension of the second doped layer covers the extension of the first doped layer to achieve overlap, and in the extension direction of the spacer region, the length of the extension of the second doped layer is greater than the length of the extension of the first doped layer.

[0036] Optionally, the end of the extension of the second doped layer extends to the junction of the spacer region and the main body of the first doped layer.

[0037] Optionally, the extension of the second doped layer extends across the spacing region and extends such that the end of the extension of the second doped layer is covered by the main body of the first 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 second doped layer also includes an extension of the second doped layer;

[0040] The extension of the second doped layer extends across the spacer region and extends such that the end of the extension of the second doped layer is covered by the main body of the first doped layer.

[0041] Optionally, the first bending structure includes multiple docking sections that are bent and connected in a direction parallel to the backlight surface.

[0042] Optionally, each docking segment has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1;

[0043] In a direction perpendicular to the extension direction of the first bending structure, the first bending structure has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1;

[0044] Where 0.00005≤T1 / δ1≤500000.

[0045] 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;

[0046] The first doped layer further includes an extension of the first doped layer, which extends at least across a portion of the spacing region and extends below the second doped layer, and the extension of the first doped layer and the second doped layer are electrically connected.

[0047] In the back contact battery of this application, by extending the extension of the first doped layer at least across a portion of the spacing region and extending below the second doped layer, a side contact surface can be formed at the electrical connection between the first and second doped layers. This side contact surface is a built-in diode with a low reverse breakdown voltage, which helps to ensure that the back contact battery has a low reverse breakdown voltage when it is shielded, thereby reducing the risk of hot spots in the back contact battery. Since the extension of the first doped layer extends below the second doped layer, in the subsequent metallization process, there will obviously be a second doped layer between the second electrode provided corresponding to the main body of the second doped layer and the extension of the first doped layer. Therefore, when printing the second electrode, there is no need to consider the relative position of the second electrode and the stacked structure, and there is no need to consider the alignment problem, which makes the processing efficiency higher. At the same time, it does not affect the current collection of the second electrode and does not cause a short circuit between the second electrode and the second doped layer.

[0048] Optionally, the second doped layer further includes an extension of the second doped layer, which extends at least across a portion of the spacing region. The extensions of the first and second doped layers are electrically connected to form a conductive connection structure. This electrical connection of the extensions prevents short circuits caused by the connection points between the electrodes and doped layers of different conductivity types during metallization.

[0049] Optionally, in the extending direction of the spacer region, the length of the extension of the first doped layer in at least one conductive connection structure is equal to the length of the extension of the second doped layer; and / or, in the extending direction of the spacer region, the length of the extension of the first doped layer in at least one conductive connection structure is greater than the length of the extension of the second doped layer; and / or, in the extending direction of the spacer region, the length of the extension of the first doped layer in at least one conductive connection structure is less than the length of the extension of the second doped layer. By extending the extension of the first doped layer below the extension of the second doped layer and having both extensions of the same length, short circuits caused by the connection between the electrode and the electrical connection points of doped layers with different conductivity types during metallization are avoided. However, due to the need for accurate alignment, this may present processing difficulties. By setting the length of the extension of the lower first doped layer to be longer, the electrical connection reliability at the overlap is higher, and it is easier to process. By lengthening the extension of the upper second doped layer, a single conductive connection structure can have three side contact surfaces. On one hand, given a fixed size, this increases the leakage channel contact area, enhancing hot spot protection. On the other hand, distributing the electrical connections to at least two sides disperses heat sources, preventing localized overheating and further improving the hot spot effect. This design reduces the total number of conductive connection structures in the overall design, ensuring high photoelectric conversion efficiency of the photovoltaic module in the forward voltage region while improving the hot spot effect. Furthermore, by increasing the number of side contact surfaces, the size of a single conductive connection structure can be reduced while maintaining or slightly increasing the total leakage channel contact area. This minimizes the impact of the conductive connection structure on the appearance and allows for greater design flexibility for the back contact cells. Therefore, by adjusting the size of the individual conductive connection structure, the total number of conductive connection structures, and their arrangement, a balance can be achieved between improving the hot spot effect and ensuring photoelectric conversion efficiency.

[0050] Optionally, the first doped layer further includes an extension of the first doped layer, which extends across the gap region and extends below the main body of the second doped layer. The extension of the first doped layer and the main body of the second doped layer are electrically connected. In the subsequent metallization process, the second electrode corresponding to the main body of the second doped layer and the extension of the first doped layer (especially the portion of the extension of the first doped layer that forms a stacked structure with the main body of the second doped layer) will obviously be spaced apart by the main body of the second doped layer. Therefore, when printing the second electrode, there is no need to consider the relative position of the second electrode and the stacked structure, and there is no need to consider alignment issues, which makes the processing efficiency higher. At the same time, it does not affect the current collection of the second electrode and will not cause a short circuit between the second electrode and the second doped layer.

[0051] Optionally, the extension of the first doped layer extends below the body portion of the adjacent second doped layer, and its end extends below the body portion of the second doped layer.

[0052] Optionally, a second electrode is disposed above the second doped layer;

[0053] In the extension direction of the extension of the first doped layer, the distance between the end of the extension of the first doped layer and the upstream side of the projection of the contact portion of the second electrode is W1, where W1 > 0.

[0054] Optionally, the width of the spacer region in the extension direction of the extension of the first doped layer is W2, where W2 > W1.

[0055] Optionally, the extension of the first doped layer extends below the main body of the adjacent second doped layer, and its end extends beyond the downstream side of the main body of the second doped layer.

[0056] Optionally, an extension of a first doped layer extends below the body portion of an adjacent second doped layer, with its end extending beyond the downstream side of the body portion of the second doped layer, and its end further extending to the upstream side of the body portion of another first doped layer adjacent to the body portion of the second doped layer.

[0057] Optionally, the main body of the first doped layer includes a strip-shaped portion of the first doped layer, and the main body of the second doped layer includes a strip-shaped portion of the second doped layer;

[0058] The first doped layer extends from a local region of the strip-shaped portion of the first doped layer toward the strip-shaped portion of the second doped layer, and the extension of the first doped layer extends across the gap region and extends below the strip-shaped portion of the second doped layer. The extension of the first doped layer and the strip-shaped portion of the second doped layer are electrically connected.

[0059] Optionally, the main body of the first doped layer includes a strip-shaped portion of the first doped layer and a connecting portion of the first doped layer, wherein the connecting portion of the first doped layer is used to connect multiple strip-shaped portions of the first doped layer; the second doped layer includes a strip-shaped portion of the second doped layer and a connecting portion of the second doped layer, wherein the connecting portion of the second doped layer is used to connect multiple strip-shaped portions of the second doped layer.

[0060] The back contact battery also includes one or more of the following structures:

[0061] The extension of the first doped layer extends from a local region of the strip-shaped portion of the first doped layer toward the strip-shaped portion of the second doped layer, and the extension of the first doped layer extends across the gap region and extends below the strip-shaped portion of the second doped layer, and the extension of the first doped layer and the strip-shaped portion of the second doped layer are electrically connected.

[0062] The extension of the first doped layer extends from a local region of the strip-shaped portion of the first doped layer toward the connection portion of the second doped layer, and the extension of the first doped layer extends across the gap region and extends below the connection portion of the second doped layer, and the extension of the first doped layer and the connection portion of the second doped layer are electrically connected.

[0063] The extension of the first doped layer extends from all or part of the connecting portion of the first doped layer toward the strip portion of the second doped layer, and the extension of the first doped layer extends across the gap region and extends below the strip portion of the second doped layer, and the extension of the first doped layer and the strip portion of the second doped layer are electrically connected.

[0064] Optionally, the extension of the first doped layer and the second doped layer form a stacked structure having at least two side mating surfaces.

[0065] Optionally, the side mating surfaces of the laminated structure have a first bending structure;

[0066] The first bending structure includes multiple docking segments that are bent and connected in a direction parallel to the backlight surface. In a second aspect of this application, a photovoltaic module is provided, wherein the photovoltaic module includes:

[0067] A battery string, formed by the electrical connection of multiple back-contact batteries as described above; and

[0068] Encapsulation layer, which covers the surface of the battery string.

[0069] 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

[0070] 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:

[0071] Figure 1 is a partial schematic diagram of some components of the back contact battery according to an embodiment of this application, showing the side mating surface.

[0072] Figure 2 is a cross-sectional schematic diagram of a back contact battery of an embodiment of this application having the side mating surface of Figure 1.

[0073] Figure 3 is a partially enlarged schematic diagram of Figure 2.

[0074] Figure 4 is a cross-sectional structural schematic diagram of a back contact battery of another embodiment of this application having the side mating surface of Figure 1.

[0075] Figure 5 is a schematic diagram of the side mating surface of Figure 1.

[0076] Figure 6 is another schematic diagram of the side mating surface of Figure 1.

[0077] Figure 7 is a SEM image of a back contact battery with the side mating surface shown in Figure 1.

[0078] 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.

[0079] 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.

[0080] Figure 10 is a partial schematic diagram of some components of the back contact battery according to an embodiment of this application, showing different shapes of side mating surfaces.

[0081] Figure 11 is a schematic diagram of the first bending structure with different shapes.

[0082] Figure 12 is a partial schematic diagram of a portion of the back contact battery according to an embodiment of this application, showing two side mating surfaces.

[0083] Figure 13 is a schematic cross-sectional view of a back contact battery of an embodiment of this application having the side mating surface of Figure 1 along the X direction in Figure 1.

[0084] Figure 14 is a schematic cross-sectional view of the back contact battery of Figure 13 along the Y direction in Figure 1.

[0085] Figure 15 is a partial schematic diagram of a portion of the back contact battery according to another embodiment of this application, showing three side mating surfaces.

[0086] Figure 16 is a schematic cross-sectional view of the back contact battery in Figure 4 along the Y direction in Figure 1.

[0087] Figure 17 is a partial schematic diagram of some components of a back contact battery according to another embodiment of this application, showing five side mating surfaces.

[0088] Figure 18 is a partial schematic diagram of some components of a back contact battery according to another embodiment of this application, showing seven side mating surfaces.

[0089] Figure 19 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.

[0090] Figure 20 is a partial schematic diagram of some components of a back contact battery according to an embodiment of this application, showing three side mating surfaces.

[0091] Figure 21 is a partial schematic diagram of some components of a back contact battery according to an embodiment of this application, wherein three side mating surfaces are shown in thick solid lines.

[0092] Figure 22 is a cross-sectional view of a back contact battery of one embodiment of this application having the side mating surface of Figure 1 along the X direction in Figure 21.

[0093] Figure 23 is a schematic cross-sectional view of the back contact battery of Figure 22 along the Y direction in Figure 1.

[0094] Figure 24 is a partial schematic diagram of a portion of the back contact battery according to another embodiment of this application, wherein three side mating surfaces are shown in thick solid lines.

[0095] Figure 25 is a schematic cross-sectional view of the back contact battery in Figure 24 along the X direction in Figure 24.

[0096] Figure 26 is a partial schematic diagram of some components of a back contact battery according to another embodiment of this application, wherein two side mating surfaces are shown in thick solid lines.

[0097] Figure 27 is a partial schematic diagram of a portion of the back contact battery according to another embodiment of this application, wherein two side mating surfaces are shown in thick solid lines.

[0098] Figure 28 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.

[0099] Figure 29 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.

[0100] Figure 30 is a partial schematic diagram of a portion of the back contact battery according to another embodiment of this application, wherein a side mating surface is shown in thick solid lines.

[0101] Figure 31 is a partial schematic diagram of a portion of the back contact battery according to another embodiment of this application, wherein a side mating surface is shown in thick solid lines.

[0102] Figure 32 is a partial schematic diagram of a portion of the back contact battery according to another embodiment of this application, wherein three side mating surfaces are shown in thick solid lines. Detailed Implementation

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0108] Implementation Plan A

[0109] This application provides a back contact battery 100, 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 one side of the backlight surface 112 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 first doped layer 200 and a portion of the second doped layer 300 are electrically connected and form a side mating surface 400, which has a first bending structure 500. It should be understood that in this document (including in embodiment A and embodiments B and C described below), "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.

[0110] In the back contact battery 100 of this application embodiment, by electrically connecting a portion of the first doped layer 200 and a portion of the second doped layer 300 to form a side contact surface 400, 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 is beneficial for the back contact battery 100 to have a low reverse breakdown voltage when it is shielded, thereby 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 due to local heat concentration. At the same time, compared with the contact surface with a planar structure, the side contact surface 400 with the first bending structure 500 can increase the contact area of ​​the leakage channel of a single side contact surface 400, effectively reducing the total number of anti-hot spot structures, and minimizing the loss of battery conversion efficiency caused by PN region contact while improving the hot spot effect.

[0111] The hot spot protection structure can also be called a hot spot protection conductive connection structure, conductive connection structure, etc. A single battery cell can have one or more conductive connection structures 700, wherein a single conductive connection structure 700 may include one or more side mating surfaces 400. A single "battery cell" can be a whole battery cell, a half battery cell, or a battery cell of other specifications.

[0112] 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.

[0113] The back contact battery 100 of this application embodiment will now be described in more detail with reference to the accompanying drawings.

[0114] 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.

[0115] 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 Figures 8 and 9, respectively. It is understood that in this document (including in embodiment A and embodiments B and C described below), "first doped layer" and "second doped layer" are only for convenience of description, and the first doped layer 200 and the second doped layer 300 can be interchanged in terms of function, setting position, etc.

[0116] In Figure 8, 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 arranged in alternating stripe patterns. A spacer region 190 is formed between the main body portions 204 and 304. Specifically, in Figure 8, the main body portion 204 of the first doped layer includes only the stripe portion 201 of the first doped layer. The main body portion 304 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 and the stripe portion 301 of the first 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] Thus, in the aforementioned first doped layer 200 and second doped layer 300, which are electrically connected and form a side mating surface 400, "a 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, and "a part 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.

[0121] 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.

[0122] The side mating surface 400 can be formed at the junction of the spacer region 190, the first doped region 191, the second doped region 192, the junction of the spacer region 190 and the first doped region 191 (also referred to as the junction of the spacer region 190 and the strip portion 201 of the first doped layer), and the junction of the spacer region 190 and the second doped region 192 (also referred to as the junction of the spacer region 190 and the strip portion 301 of the second doped layer). Specifically, when the side mating surface 400 is formed in the spacer region 190, all or part of the extension 203 of the first doped layer is electrically connected to all or part of the extension 303 of the second doped layer to form the side mating surface 400; when the side mating surface 400 is formed at the junction of the first doped region 191, or the spacer region 190 and the first doped region 191, a part of the strip-shaped portion 201 of the first doped layer is electrically connected to all or part of the extension 303 of the second doped layer to form the side mating surface 400; when the side mating surface 400 is formed at the junction of the second doped region 192, or the spacer region 190 and the second doped region 192, a part of the strip-shaped portion 301 of the second doped layer is electrically connected to all or part of the extension 203 of the first doped layer to form the side mating surface 400.

[0123] The side mating surface 400 can be formed by mating a portion of the first doped layer 200 with a portion of the second doped layer 300, or by overlapping a portion of the first doped layer 200 with a portion of the second doped layer 300. For example, a portion of the first doped layer 200 overlaps a portion of the second doped layer 300, and vice versa. Compared to forming a side mating surface by mating, the side mating surface formed by overlapping has higher electrical connection reliability, and a top-to-top mating surface may also be formed between the top surface of the lower doped layer and the bottom surface of the upper doped layer, which is more conducive to improving the hot spot prevention effect. Referring to Figure 2, a portion of the second doped layer 300 overlaps a portion of the first doped layer 200 to form the side mating surface 400. Referring to Figure 4, a portion of the first doped layer 200 and a portion of the second doped layer 300 are mated together to form the side mating surface 400.

[0124] 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. Alternatively, the first doped layer 200 may be formed on the semiconductor substrate 101, and the second doped layer 300 may be formed within the semiconductor substrate 101. Specifically, when both the first doped layer 200 and the second doped layer 300 are formed within the semiconductor substrate 101, that is, when the first doped layer 200 and the second doped layer 300, having a certain thickness, exist within the semiconductor substrate 101, the side mating surface 400 may be formed by mating between a portion of the first doped layer 200 and a portion of the second doped layer 300, or by overlapping between a portion of the first doped layer 200 and a portion of the second doped layer 300. When both the first doped layer 200 and the second doped layer 300 are formed on the semiconductor substrate 101, the side mating surface 400 can be formed by mating between a portion of the first doped layer 200 and a portion of the second doped layer 300, or by overlapping between a portion of the first doped layer 200 and a portion of the second doped layer 300. 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, and the height of the semiconductor substrate 101 corresponding to the main body portion 204 of the first doped layer 200 is higher than the height of the semiconductor substrate 101 corresponding to the main body portion 304 of the second doped layer 300, the side mating surface 400 can be formed by mating all or part of the extension portion 303 of the second doped layer with a portion of the first doped layer 200, or by overlapping between all or part of the extension portion 303 of the second doped layer and a portion of the first doped layer 200.

[0125] Regarding the contact method between a portion of the first doped layer 200 and a portion of the second doped layer 300, the portion of the first doped layer 200 and the portion of the second doped layer 300 can directly contact each other to form a side mating surface 400; the portion of the first doped layer 200 and the portion of the second doped layer 300 can also indirectly contact each other to form a side mating surface 400. That is, other layer structures may be provided between the portion of the first doped layer 200 and the portion of the second doped layer 300 as needed, as long as the portion of the first doped layer 200 and the portion of the second doped layer 300 can form an electrical connection.

[0126] For example, in Figure 8, at mark 801, the side mating surface 400 is formed by mating between the extension 203 of the first doped layer and the extension 303 of the second doped layer at the spacer region 190; at mark 802, the side mating surface 400 is formed by overlapping between a portion of the strip portion 201 of the first doped layer and the extension 303 of the second doped layer at the first doped region 191; and at mark 803, the side mating surface 400 is formed by overlapping between the extension 203 of the first doped layer and a portion of the strip portion 301 of the second doped layer at the second doped region 192.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] Thus, in the aforementioned electrical connection between a portion of the first doped layer 200 and a portion of the second doped layer 300 to form a side mating surface 400, the "partial portion of the first doped layer" can be a portion of the strip-shaped portion 201 of the first doped layer, or all or a portion of the connecting portion 202 of the first doped layer, or all or a portion of the extension portion 203 of the first doped layer; similarly, the "partial portion of the second doped layer" can be a portion of the strip-shaped portion 301 of the second doped layer, or all or a portion of the connecting portion 302 of the second doped layer, or all or a portion of the extension portion 303 of the second doped layer. It should be understood that typically, a portion of the first doped layer 200 and a portion of the second doped layer 300 located adjacent to each other are electrically connected to form the side mating surface 400.

[0132] As for the location of the side mating surface 400, similar to the previous description, it can be at the junction of the spacer region 190, the first doped region 191, the second doped region 192, the third doped region 193, the fourth doped region 194, the junction of the spacer region 190 and the first doped region 191 (also referred to as the junction of the spacer region 190 and the strip portion 201 of the first doped layer), the junction of the spacer region 190 and the second doped region 192 (also referred to as the junction of the spacer region 190 and the strip portion 301 of the second doped layer), the junction of the spacer region 190 and the third doped region 193 (also referred to as the junction of the spacer region 190 and the extension portion 203 of the first doped layer), the junction of the spacer region 190 and the fourth doped region 194 (also referred to as the junction of the spacer region 190 and the connecting portion 302 of the second doped layer), etc., which will not be elaborated here.

[0133] As for the positions of the first doped layer 200 and the second doped layer 300 relative to the semiconductor substrate 101, the specific structure of the spacer region 190, the formation method 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, they are similar to those described above and will not be repeated here.

[0134] For example, in Figure 9, at mark 901, the side mating surface 400 may be formed between 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 portion 301 of the second doped layer) and a portion of the end of the strip portion 301 of the second doped layer; at mark 902, the side mating surface 400 may be formed between a portion of the strip portion 201 of the first doped layer and 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); at mark 903, the side mating surface 400 may be formed between a portion of the end of the strip portion 201 of the first doped layer and 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).

[0135] In the back contact battery 100 of this application embodiment, the side contact surface 400 has a first bending structure 500; in other words, the side contact surface 400 is not a flat surface. Specifically, in a direction parallel to the backlight surface 112, a single side contact surface 400 has a bending unfolding length L (not shown in the figure) and an end straight line length D (see Figures 1 and 5, where the distance between point a and point b in Figure 1), wherein L > 1.001D. By limiting the relationship between the bending unfolding length L and the end straight line length D to L > 1.001D, it can be ensured that the side contact surface 400 forms a bend.

[0136] In this document (including in Embodiment A and Embodiments B and C described below), "bend unfolded length" refers to the total length of all edge portions included in the bend structure. In this sense, the bend structure can be considered as consisting of multiple broken lines (composed of straight line segments) and / or multiple curves between two ends, and the total length of all edge portions refers to the total length of all included broken line or curve portions. "End straight length" refers to the straight-line distance between the projection points of the two ends of the bend structure in a direction parallel to the extension direction of the bend structure. The two ends of the bend structure refer to the two ends corresponding to the following two projection points: the two farthest projection points of the selected local segment's bend structure in a direction parallel to the extension direction of the bend structure. It can be understood that the bend unfolded length of the first bend structure of the local segment is the total length of all edge portions (i.e., all broken line or curve portions included in the first bend structure) included in the first bend structure of the local segment; the end straight length of the first bend structure of the local segment refers to the straight-line distance between the projection points of the two ends of the selected local segment's bend structure in a direction parallel to the extension direction of the bend structure.

[0137] In some embodiments, under a 10-micron step measurement condition, L ≥ 1.05D, for example, L can be 1.05D, 1.08D, 1.10D, or 1.20D. 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 complex to measure a complete side mating surface, 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, where the end straight length D of the one or more local segments is 10 microns. The bending unfolded length L of the first bent structure of the one or more local segments is measured (the bending unfolded length of the first bent structure of each local segment can be obtained by measurement or approximation (e.g., considering the first bent structure of each local segment as composed of multiple straight segments connected together and measuring and summing the lengths of these multiple straight segments), thereby directly obtaining or averaging the relationship between L and D.

[0138] 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, or 5D. By ensuring L ≥ 1.2D, the bent structure of the side contact surface 400 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 localized heat concentration, effectively reducing the risk of hot spots on 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, or 10D. When L exceeds the aforementioned range, it leads to excessive etching difficulty, affecting production efficiency.

[0139] 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, or 3000 micrometers.

[0140] 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, or 8000 micrometers.

[0141] 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 2, 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 document (including in Embodiment A and Embodiments B and C described below), "direction parallel to the backlight surface" refers to the extension direction of the second horizontal side, also known as the "extension direction of the side mating surface" or the "extension direction of the first bending structure." It should be understood that in this document (including in Embodiment A and Embodiments B and C described below), when describing directional relationships such as "parallel to," "perpendicular to," etc., it includes both precise "parallel to" and "perpendicular to," as well as generally, substantially, or approximately "parallel to" and "perpendicular to." Thus, the bending unfolded length L and the end straight line length D are respectively the bending unfolded length and the end straight line length of the second horizontal side. For example, in the example shown in Figure 1, there is one side mating surface 400. In this case, the direction parallel to the backlight surface 112, the extension direction of the side mating surface 400, and the extension direction of the first bending structure 500 are the vertical directions of Figure 1. In the example shown in Figure 10h), 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 first bending structure 500. Specifically, the directions parallel to the backlight surface 112, the extension directions of the side mating surface 400, and the extension directions of the first bending structure 500 of the first side mating surface 400 located at the top and the second side mating surface 400 located at the bottom are the horizontal directions of Figure 10h, while the directions parallel to the backlight surface 112, the extension directions of the side mating surface 400, and the extension directions of the first bending structure 500 of the third side mating surface 400 located in the middle are the vertical directions of Figure 10h.

[0142] The first bending structure 500 can be any structure that makes the side mating surface 400 no longer a flat surface. An exemplary configuration of the first bending structure 500 will be described in detail below with reference to the accompanying drawings.

[0143] In some embodiments, the first bending structure 500 includes a plurality of first mating sections 510 that are bent and connected in a direction parallel to the backlight surface 112, as shown in Figures 1, 5, and 10. By configuring the first bending structure 500 to include a plurality of bent and connected first mating sections 510, the presence of the first bending structure 500 can significantly increase the leakage current channel contact area of ​​a single side mating surface 400, effectively preventing local overheating of the back contact battery 100 and effectively reducing the total number of side mating surfaces 400.

[0144] In the first bending structure 500, the section that has a complete first protrusion is regarded as a "first docking section".

[0145] Referring to Figures 1, 5, 7, 10, and 11, each first docking section 510 may have a first protrusion (not labeled in the figures), and the first protrusion may have one or more of the following shapes: arc-shaped, square-shaped, trapezoidal, triangular, or irregular.

[0146] In this article, when describing a shape, it includes both the standard shape and similar shapes that are generally similar to the shape. For example, an arc shape includes the standard arc shape and a generally arc shape; a square shape includes the standard square shape and a generally square shape; a trapezoid shape includes the standard trapezoid shape and a generally trapezoid shape; and a triangle shape includes the standard triangle shape and a generally triangle shape. Irregular shapes are those that differ significantly from standard, common, regular shapes and cannot be categorized.

[0147] The first protrusions of the plurality of first mating sections 510 in a single first bending structure 500 may have the same shape, and the protrusion directions of the first protrusions may be the same. Alternatively, the first protrusions of the plurality of first mating sections 510 in a single first bending structure 500 may have different shapes, and the protrusion directions of the first protrusions may be the same. The "protrusion direction of the first protrusion" is a direction that is substantially perpendicular to the extension direction of the first bending structure 500.

[0148] In Figure 1, the side mating surface 400 is formed in the interval region 190, and the multiple first protrusions of the multiple first mating sections 510 have arc shapes, and the protrusion directions of the multiple first protrusions are the same.

[0149] In Figure 7, the side mating surface 400 is formed at the junction of the spacer region 190 and the first doped region 191, and the multiple first protrusions of the multiple first mating sections 510 have arc-shaped, trapezoidal, and irregular shapes.

[0150] In Figure 10a), the side mating surface 400 is formed at the junction of the spacer region 190 and the first doped region 191 in a mating manner. Similar to Figure 1, the multiple first protrusions of the multiple first mating sections 510 have arc shapes, and the protrusion directions of the multiple first protrusions are the same.

[0151] In Figure 10b), the side mating surface 400 is formed at the junction of the spacer region 190 and the first doped region 191 in a mating manner. The multiple first protrusions of the multiple first mating sections 510 are square in shape, and the protrusion directions of the multiple first protrusions are the same.

[0152] In Figure 10c), the side mating surface 400 is formed at the junction of the spacer region 190 and the first doped region 191 in a mating manner. The multiple first protrusions of the multiple first mating sections 510 have arc shapes and the protrusion directions of the multiple first protrusions are the same.

[0153] In Figure 10d), the side mating surface 400 is formed at the junction of the spacer region 190 and the first doped region 191 in a mating manner. The multiple first protrusions of the multiple first mating sections 510 are triangular in shape, and the protrusion directions of the multiple first protrusions are the same.

[0154] In Figure 10e), the side mating surface 400 is formed in the spaced region 190 in a mating manner, similar to Figure 10d). The multiple first protrusions of the multiple first mating sections 510 are triangular in shape, and the protrusion directions of the multiple first protrusions are the same.

[0155] In Figure 10f), the side mating surface 400 is formed at the junction of the spacer region 190 and the first doped region 191 in an overlapping manner, similar to Figures 10d) and 10e). The multiple first protrusions of the multiple first mating sections 510 have triangular shapes, and the protrusion directions of the multiple first protrusions are the same.

[0156] In Figures 10g), 10h), and 10i), multiple side mating surfaces 400 are formed in an overlapping manner in the spacer region 190, and multiple first protrusions of multiple first mating sections 510 of each side mating surface 400 have irregular shapes.

[0157] To more clearly illustrate the first mating section 510 of the first bending structure 500, a schematic diagram of various forms of the first bending structure 500 on the side mating surface 400 is shown separately in FIG11.

[0158] In Figure 11a), similar to Figures 1 and 10c), in the first bending structure 500, the multiple first protrusions of the multiple first mating sections 510 have arc-shaped shapes, and the protrusion directions of the multiple first protrusions are the same. The first mating section 510 includes an arc-shaped first protrusion and an arc-shaped recess located on both sides of the arc-shaped first protrusion. That is, the first mating section 510 is the section located between the vertices of two adjacent arc-shaped recesses.

[0159] In Figure 11b), similar to Figure 10a), in the first bending structure 500, the multiple first protrusions of the multiple first mating sections 510 have arc shapes, and the multiple first protrusions have the same protrusion direction. The first mating section 510 includes only the arc-shaped first protrusions. That is, the first mating section 510 is the section located between the intersection of two adjacent arc-shaped first protrusions.

[0160] In Figure 11c), similar to Figure 10b), in the first bending structure 500, the multiple first protrusions of the multiple first mating sections 510 are square in shape, and the protrusion directions of the multiple first protrusions are the same. The first mating section 510 includes a square first protrusion and a square recess located on both sides of the square first protrusion. That is, the first mating section 510 is the section located between the midpoints of the top edges of two adjacent square recesses.

[0161] In Figure 11d), in the first bending structure 500, the multiple first protrusions of the multiple first docking sections 510 have trapezoidal shapes, and the protrusion directions of the multiple first protrusions are the same. The first docking section 510 includes only the trapezoidal first protrusions. That is, the first docking section 510 is the section located between the intersection of the first protrusions of two adjacent trapezoids.

[0162] In Figure 11e), in the first bending structure 500, the multiple first protrusions of the multiple first docking sections 510 have trapezoidal shapes and the protrusion directions of the multiple first protrusions are the same. The first docking section 510 includes the trapezoidal first protrusion and the square recesses located on both sides of the trapezoidal first protrusion. That is, the first docking section 510 is the section located between the midpoints of the top edges of two adjacent square recesses.

[0163] In Figure 11f), similar to Figure 10f), in the first bending structure 500, the multiple first protrusions of the multiple first docking sections 510 are triangular in shape, and the protrusion directions of the multiple first protrusions are the same. The first docking section 510 includes only the triangular first protrusions. That is, the first docking section 510 is the section located between the intersection of the first protrusions of two adjacent triangles.

[0164] In Figures 11g and 11h, in the first bending structure 500, the first protrusions of the plurality of first mating sections 510 have irregular shapes, wherein the first mating section 510 includes a section between the apex or the midpoint of the top edge of two recesses located on both sides of a first protrusion.

[0165] In Figure 11i), in the first bending structure 500, some of the first protrusions of the first mating sections 510 have an arc shape, while others have a square shape, and the protrusion directions of the multiple first protrusions are the same.

[0166] In Figure 11j), in the first bending structure 500, some of the first protrusions of the first mating sections 510 have an arc shape, some of the first protrusions of the first mating sections 510 have a square shape, and some of the first protrusions of the first mating sections 510 have a triangular shape, and the protrusion direction of the multiple first protrusions is the same.

[0167] The features of the bent structure described above with reference to Figure 11 also apply to the schemes described below in Scheme B and Scheme C.

[0168] The bending situation of the first bending structure 500 is described in detail below with reference to the attached diagram.

[0169] Referring to Figure 5, each first mating segment 510 has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1. In a direction perpendicular to the extension direction of the first bending structure 500, the first bending structure 500 has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1. In Figure 5, the extension direction of the first bending structure 500 is the up-down direction (as indicated by the leftmost line with arrows at both ends in Figure 5), and the direction perpendicular to the extension direction of the first bending structure 500 is the left-right direction. The maximum point of the first protrusion is either the farthest protrusion point of the first protrusion or a point on the farthest protrusion line of the first protrusion. The first maximum point of the first bending structure 500 is the farthest point among the multiple maximum points of the multiple first protrusions, and the first minimum point is the farthest point among the intersections of the recesses or the first protrusions.

[0170] In some embodiments, 0.00005 ≤ T1 / δ1 ≤ 500000. T1 / δ1 can be, for example, 0.00005, 0.002, 0.04, 6, 800, 5000, 80000, or 500000. T1, δ1, and T1 / δ1 are parameters used to characterize the bending condition of the first bending structure 500. When T1 / δ1 increases, the bending is gentler, the effect of the first bending structure 500 on increasing the contact area of ​​the leakage channel on the side mating surface 400 weakens, and the effect on improving the hot spot prevention effect weakens, but the requirement for etching precision decreases, making it more conducive to processing. When T1 / δ1 decreases, the bending is steeper, the effect of the first bending structure 500 on increasing the contact area of ​​the leakage channel on the side mating surface 400 strengthens, and the effect on improving the hot spot prevention effect strengthens, but the requirement for etching precision increases, making it less conducive to processing. Therefore, by adjusting the ratio of T1 to δ1, a balance can be achieved between increasing the contact area of ​​the leakage current channel and processing efficiency.

[0171] The value of T1 can range from 0.01 to 500 micrometers. For example, T1 can be 0.01 micrometers, 0.1 micrometers, 2 micrometers, 40 micrometers, 200 micrometers, or 500 micrometers.

[0172] The value of δ1 can range from 0.001 to 200 micrometers. Examples of δ1 values ​​are 0.001 micrometers, 0.01 micrometers, 0.1 micrometers, 2 micrometers, 40 micrometers, and 200 micrometers. If δ1 is too small, the effect on preventing hot spots will be weakened; if δ1 is too large, it will be detrimental to processing.

[0173] The features described above with reference to Figure 5 also apply to the schemes described below in Implementation Scheme B and Implementation Scheme C.

[0174] In some embodiments, referring to Figures 3 and 6, at least one of the plurality of first mating sections 510 has a second bending structure 600. Compared to a side mating surface 400 having only a first bending structure 500, a side mating surface 400 having both a first bending structure 500 and a second bending structure 600 can increase the contact area of ​​the leakage path of a single side mating surface 400. At the same time, the presence of the second bending structure 600 also makes the leakage points more evenly distributed, further effectively preventing local overheating of the back contact battery 100.

[0175] The second bending structure 600 can be any structure that makes the bending of the first mating section of the first bending structure 500 more complex. In some embodiments, the second bending structure 600 may include a plurality of second mating sections 610 that are bent and connected in a direction parallel to the backlight surface 112, as shown in FIG6. By configuring the second bending structure 600 to include a plurality of second mating sections 610 that are bent and connected, it can be ensured that the presence of the second bending structure 600 can further increase the contact area of ​​the leakage current channel of a single side mating surface 400, while making the leakage points more evenly distributed.

[0176] In the second bending structure 600, the segment with a single complete second protrusion is designated as a "second docking segment". Similar to the first docking segment 510, each second docking segment 610 may have a second protrusion, which may have one or more of the following shapes: arc-shaped, square-shaped, trapezoidal, triangular, or irregular, which will not be elaborated here.

[0177] However, unlike the first bending structure 500, the second bending structure 600 is an attachment to the first mating section 510, and the first mating section 510 itself has a first protrusion. The multiple line segments constituting the first protrusion obviously have different orientations. Therefore, the second bending structure 600 on a single first mating section 510 will have different extension directions. For example, as shown in Figure 6, the multiple first protrusions of the multiple first mating sections 510 of the first bending structure 500 have an arc shape. For the first mating section 510 marked with 510 in Figure 6, it has a first line segment extending outwards (not labeled in the figure) and a second line segment extending inwards (not labeled in the figure), or it can be considered that the first line segment protrudes outwards, and the second line segment is recessed inwards from the protruding end of the first line segment. The first line segment has a first extension direction, and the second line segment has a second extension direction; the first and second extension directions are at an angle. In other words, the second bending structure 600 on the first line segment has a first extending direction, and the second bending structure 600 on the second line segment has a second extending direction. In the following description of the bending of the second bending structure 600, we will refer to the second bending structure 600, the second mating section 610, and the second protrusion, all located in the same extending direction. The "protrusion direction of the second protrusion" is a direction approximately perpendicular to the extending direction of the line segment in the first mating section 510 where it is located.

[0178] The bending of the second bending structure 600 is described in detail below with reference to the attached diagram.

[0179] Referring to Figure 6, each second docking section 610 has a second protrusion, and the distance between the maximum points of two adjacent second protrusions is T2; in a direction perpendicular to the extension direction of the second bending structure 600, the second bending structure 600 has a second maximum point and a second minimum point, and the distance between the second maximum point and the second minimum point is δ2.

[0180] In embodiments where the back contact battery 100 has a first bending structure 500 and a second bending structure 600, T1>T2; and / or, δ1>δ2. As previously mentioned, T1 and δ1 are parameters used to characterize the bending condition of the first bending structure 500. Similarly, T2 and δ2 are parameters used to characterize the bending condition of the second bending structure 600. Typically, T1>T2; and δ1>δ2. By limiting T1>T2 and δ1>δ2, the first bending structure 500 and the second bending structure 600 can be distinguished from each other, while the bending shape of the second bending structure 600 generally follows the trajectory of the first bending structure 500, thereby ensuring that the arrangement of the second bending structure 600 does not excessively affect the processing.

[0181] In some embodiments, T1 can be 5-100 times T2. For example, T1 can be 5, 20, 30, 60, 80, or 100 times T2. If the difference between T1 and T2 is too small, the effect of further improving the anti-hot spot effect will be weakened; if the difference between T1 and T2 is too large, it will be detrimental to processing.

[0182] The value of T2 can range from 0.001 to 50 micrometers. For example, T2 can be 0.001 micrometers, 0.01 micrometers, 0.1 micrometers, 2 micrometers, 30 micrometers, and 50 micrometers.

[0183] The value of δ2 can range from 0.0001 to 20 micrometers. Examples of δ2 values ​​are 0.0001 micrometers, 0.001 micrometers, 0.01 micrometers, 0.2 micrometers, 4 micrometers, 10 micrometers, and 20 micrometers. If δ2 is too small, the effect of further improving the anti-hot spot effect will be weakened; if δ2 is too large, it will be detrimental to processing.

[0184] In some embodiments, as shown in Figures 2 and 3, a first portion of the first doped layer 200 and a second portion of the second doped layer 300 are electrically connected and form a first side mating surface 401; the second portion of the second doped layer 300 is also electrically connected to the semiconductor substrate 101 and forms a second side mating surface 402; wherein both the first side mating surface 401 and the second side mating surface 402 have a first bending structure 500, and the second side mating surface 402 also has a second bending structure 600. Considering that the lateral transport speed of charge carriers between the first doped layer 200 and the second doped layer 300 is relatively fast, while the lateral transport speed between the semiconductor substrate 101 and the second portion of the second doped layer 300 is relatively slow, by providing the second bending structure 600 on the second side mating surface 402, the contact area of ​​the leakage channel of a single second side mating surface 402 can be increased, thereby accelerating the lateral transport speed at the second side mating surface 402. At the same time, the presence of the second bending structure 600 also makes the leakage points more uniformly dispersed, further effectively preventing local overheating of the back contact battery 100.

[0185] In this embodiment, the second bending structure 600 is formed only between the second portion of the second doped layer 300 and the portion of the semiconductor substrate 101 where the height difference is formed, thus eliminating the need for additional processing steps. The second bending structure 600 is typically formed on the side of the semiconductor substrate 101 where the height difference is formed during alkaline etching. When no height difference is formed on the semiconductor substrate 101, the second bending structure 600 will not form during alkaline etching.

[0186] As mentioned above, a single conductive connection structure 700 may include one or more side mating surfaces 400.

[0187] In some embodiments, a conductive connection structure 700 is provided between a portion of the first doped layer 200 and a portion of the second doped layer 300, wherein a single conductive connection structure 700 includes at least two of the aforementioned side mating surfaces 400, as shown in FIG10g), FIG10h), and FIG10i).

[0188] By configuring a single conductive connection structure 700 to include at least two side mating surfaces 400, on the one hand, when the size of a single conductive connection structure is fixed, the contact area of ​​the leakage channel of the single conductive connection structure 700 can be increased, enhancing the hot spot prevention function. On the other hand, distributing the electrical connection points to at least two sides can disperse the heat points, avoid local overheating, and improve the hot spot effect. In the overall design, this design can reduce the total number of conductive connection structures 700, ensuring that the photovoltaic module has a high photoelectric conversion efficiency in the forward voltage region while improving the hot spot effect. By increasing the number of side mating surfaces, while keeping the total leakage channel contact area of ​​a single conductive connection structure 700 unchanged or slightly increasing it, the size of a single conductive connection structure 700 can be reduced, minimizing its impact on the appearance and allowing for a larger design space for the back contact cell 100. Thus, by adjusting the size of the single conductive connection structure 700, the total number of conductive connection structures 700, the arrangement, etc., a balance can be achieved between improving the hot spot effect and ensuring photoelectric conversion efficiency.

[0189] It is understood that when a single battery cell has multiple conductive connection structures 700, all conductive connection structures 700 may each include at least two side mating surfaces 400, or only some conductive connection structures 700 may each include at least two side mating surfaces 400.

[0190] Regarding the positions of the first doped layer 200 and the second doped layer 300 relative to the semiconductor substrate 101, when both the first doped layer 200 and the second doped layer 300 are formed within the semiconductor substrate 101 (i.e., the first doped layer 200 and the second doped layer 300, having a certain thickness, exist within the semiconductor substrate 101), the conductive connection structure 700 having at least two side mating surfaces 400 can be formed by overlapping a portion of the first doped layer 200 and a portion of the second doped layer 300, or by overlapping a portion of the first doped layer 200 and a portion of the second doped layer 300 at a first position and mating at a second position. Compared to side mating surfaces formed by overlapping, side mating surfaces formed by mating have higher electrical connection reliability, and a top mating surface may also be formed between the top surface of the lower doped layer and the bottom surface of the upper doped layer, thereby further improving the hot spot prevention effect. When both the first doped layer 200 and the second doped layer 300 are formed on the semiconductor substrate 101, the conductive connection structure 700 having at least two side mating surfaces 400 can be formed by overlapping between a part of the first doped layer 200 and a part of the second doped layer 300 (as shown in Figures 1 to 3), or it can be formed by overlapping at a first position and mating at a second position between a part of the first doped layer 200 and a part of the second doped layer 300 (as shown in Figures 6 and 7). When the first doped layer 200 is formed within the semiconductor substrate 101 and the second doped layer 300 is formed on top of the semiconductor substrate 101, the height of the semiconductor substrate 101 corresponding to the main body portion 204 of the first doped layer 200 is higher than the height of the semiconductor substrate 101 corresponding to the main body portion 304 of the second doped layer 300. The conductive connection structure 700 having at least two side mating surfaces 400 can be formed by overlapping all or part of the extension portion 303 of the second doped layer with a part of the main body portion 204 of the first doped layer, or by overlapping at a first position and mating at a second position between all or part of the extension portion 303 of the second doped layer and a part of the main body portion 204 of the first doped layer. There can be one or more of the aforementioned first and second positions.

[0191] Regarding the number of side mating surfaces 400 in a single conductive connection structure 700, a single conductive connection structure 700 may have at least two side mating surfaces 400, for example, a single conductive connection structure 700 may have two side mating surfaces 400 (see Figure 10g)), three side mating surfaces 400 (see Figure 10h)), four side mating surfaces 400, five side mating surfaces 400 (see Figure 10i)), six side mating surfaces 400, or even up to nine side mating surfaces 400, etc.

[0192] Referring again to Figures 10g, 10h, and 10i), a spacer region 190 is provided between the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer; the first doped layer 200 also includes an extension portion 203 of the first doped layer, and the second doped layer 300 also includes an extension portion 303 of the second doped layer. The extension portions 203 of the first doped layer and the extension portions 303 of the second doped layer are electrically connected at the spacer region 190 to form a conductive connection structure 700, wherein each conductive connection structure 700 includes at least two side mating surfaces 400.

[0193] In some embodiments, as shown in FIG10g), the extension 203 of the first doped layer and the extension 303 of the second doped layer are electrically connected at the spacer region 190 to form a conductive connection structure 700, wherein the extension 203 of the first doped layer and the extension 303 of the second doped layer are staggered. In this case, a single conductive connection structure 700 includes two side mating surfaces 400. The staggered overlap of the extension 203 of the first doped layer and the extension 303 of the second doped layer reduces the processing difficulty and is beneficial to practical applications, allowing the leakage channel contact area of ​​a single conductive connection structure 700 to be increased without excessively affecting processing efficiency. "Staggered overlap" at the spacer region means that at the spacer region, a portion of the end of the extension 203 of the first doped layer and a portion of the end of the extension 303 of the second doped layer are overlapped. Taking the staggered overlap of the extension 303 of the second doped layer over the extension 203 of the first doped layer as an example, only a portion of two of the three sides of the end of the extension 203 of the first doped layer are covered by the extension 303 of the second doped layer. Viewed from the semiconductor substrate, the projections of the end of the first doped layer extension 203 and the end of the second doped layer extension 303 on the semiconductor substrate only partially overlap. Here, the specific length ratio of the end to the entire extension is not limited and can be adjusted as needed. Assume that the length of the first doped layer extension 203 in its extension direction is m1, and its width in the direction perpendicular to its extension direction is n1; the length of the second doped layer extension 303 in its extension direction is m2, and its width in the direction perpendicular to its extension direction is n2; where m1 and m2 can be the same or different; n1 and n2 can be the same or different. Figure 10g shows a structure with staggered overlap in the spacing region 190, where a single conductive connection structure 700 includes two side mating surfaces 400; where both side mating surfaces 400 are formed between the first doped layer extension 203 and the second doped layer extension 303.

[0194] In other embodiments, as shown in FIG10h, the extension 203 of the first doped layer and the extension 303 of the second doped layer are electrically connected at a spacing region 190 to form a conductive connection structure 700, wherein the extension 303 of the second doped layer covers the extension 203 of the first doped layer to achieve an overlap, and in a direction perpendicular to the extension direction of the extension, the length of the extension 303 of the second doped layer is greater than the length of the extension 203 of the first doped layer. In this case, a single conductive connection structure 700 may include three or more side mating surfaces 400. Covering and overlapping the extension 203 of the first doped layer and the extension 303 of the second doped layer increases the processing difficulty compared to staggered overlap, since it is necessary to ensure that the length of the extension 303 of the second doped layer is greater than the length of the extension 203 of the first doped layer and that the two overlap. However, it is more effective in increasing the contact area of ​​the leakage channel of a single conductive connection structure 700 and in improving the hot spot effect. In the spacer region 190, "overlapping" means that at spacer region 190, a partial area of ​​the end of the extension 303 of the second doped layer overlaps the entire area of ​​the end of the extension 203 of the first doped layer, forming an overlap. All three sides of the end of the extension 203 of the first doped layer are covered by the extension 303 of the second doped layer. Viewed from the semiconductor substrate, the projection of the end of the extension 303 of the second doped layer completely covers the projection of the end of the extension 203 of the first doped layer. Similar to the previous example, the specific length ratio of the end to the entire extension is not limited and can be adjusted as needed. Assume that the length of the extension 203 of the first doped layer in its extension direction is m1, and its width in the direction perpendicular to its extension direction is n1; the length of the extension 303 of the second doped layer in its extension direction is m2, and its width in the direction perpendicular to its extension direction is n2; where m1 and m2 can be the same or different; n2 > n1. Figure 10h shows a structure with overlapping overlays in the spacer region 190, wherein a single conductive connection structure 700 includes three side mating surfaces 400; wherein the three side mating surfaces 400 are formed between the extension 203 of the first doped layer and the extension 303 of the second doped layer.

[0195] Furthermore, the end of the extension 303 of the second doped layer extends to the junction of the spacer region 190 and the main body 204 of the first doped layer. In this case, a single conductive connection structure 700 includes more than three side mating surfaces 400. In the case of overlapping, by extending the end of the extension 303 of the second doped layer to the junction of the spacer region 190 and the main body 204 of the first doped layer, the number of side mating surfaces 400 of a single conductive connection structure 700 can be further increased, thereby further increasing the leakage channel contact area of ​​the single conductive connection structure 700 and further improving the effect of hot spot effect. Figure 10i) shows a structure in which the spacer region 190 overlaps and the end of the extension 303 of the second doped layer extends to the junction of the spacer region 190 and the main body 204 of the first doped layer. The single conductive connection structure 700 includes five side mating surfaces 400. The three side mating surfaces 400 in the spacer region are formed by the extension 303 of the second doped layer overlapping the extension 203 of the first doped layer. The two side mating surfaces 400 at the junction of the spacer region and the main body 204 of the first doped layer are formed by mating between the end of the extension 303 of the second doped layer and the main body 204 of the first doped layer.

[0196] The overall structure of the back contact battery 100 according to an embodiment of this application will be described below with reference to Figures 2 and 4.

[0197] As shown in Figures 2 and 3, the back contact battery 100 includes a semiconductor substrate 101, a first doped layer 200, and a second doped layer 300. The main body portions 204 of the first doped layer and 304 of the second doped layer are alternately distributed on one side of the backlight surface 112 of the semiconductor substrate 101. The first doped layer 200 and the second doped layer 300 have opposite conductivity types. The surface of the semiconductor substrate 101 corresponding to the main body portion 304 of the second doped layer is lower than the surface of the semiconductor substrate 101 corresponding to the first doped layer 200. The extension portion 303 of the second doped layer... A first side mating surface 401 is formed between the side of the first doped layer extension 203 and the second doped layer extension 303, and a second side mating surface 402 is formed between the second doped layer extension 303 and the side of the semiconductor substrate 101 corresponding to the first doped layer extension 203. The first side mating surface 401 has a first bending structure 500, and the second side mating surface 402 has a first bending structure 500 and a second bending structure 600.

[0198] As shown in Figure 4, 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 one side of the backlight surface 112 of the semiconductor substrate 101. The first doped layer 200 and the second doped layer 300 have opposite conductivity types. The surface of the semiconductor substrate 101 corresponding to the main body portion 304 of the second doped layer is lower than the surface of the semiconductor substrate 101 corresponding to the first doped layer 200. The extension portion 303 of the second doped layer is connected to the extension portion 203 of the first doped layer in the interval region 190, thereby forming a first side connection surface 401 between the side of the extension portion 203 of the first doped layer and the extension portion 303 of the second doped layer. At the same time, a second side connection surface 402 is formed between the extension portion 303 of the second doped layer and the side of the semiconductor substrate 101 corresponding to the extension portion 203 of the first doped layer. The first side connection surface 401 has a first bending structure 500, and the second side connection surface 402 has a first bending structure 500 and a second bending structure 600.

[0199] The back contact battery 100 shown in FIG2 may further include a first dielectric layer 131 between the first doped layer 200 and the semiconductor substrate 101, a second dielectric layer 132 between the second doped layer 300 and the semiconductor substrate 101, an insulating layer 150 between the extension 203 of the first doped layer and the extension 303 of the second doped layer, a surface passivation layer 140 above the first doped layer 200 and the second doped layer 300, a first electrode 121, and a second electrode 122. Similarly, the back contact battery 100 shown in FIG4 may further include a dielectric layer 130 between the first doped layer 200, the second doped layer 300, and the semiconductor substrate 101, a surface passivation layer 140 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 can 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 can pass through the surface passivation layer 140 to contact the first doped layer 200 or the second doped layer 300 to form an electrical connection.

[0200] 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 in the back contact battery only includes multiple current collector electrodes (multiple current collector electrodes include multiple first electrodes 121 and multiple second electrodes 122). The current collector electrodes can also be called fine grid lines. These multiple current collector electrodes can extend along a first direction and be spaced apart along a second direction. Alternatively, the back contact battery 100 of this 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 a structure that only extends through a part of the battery cell. The above description of the electrode structure also applies to the schemes described in Scheme B and Scheme C below.

[0201] 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.

[0202] The semiconductor substrate can be a silicon substrate. The silicon substrate can be N-type or P-type silicon, with a thickness of 30-500 micrometers. The backlighting side and the light-facing side of the semiconductor substrate can be planar. Alternatively, the light-facing side of the semiconductor substrate can also be textured.

[0203] 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, 3-3000 nm. Preferably, the upper doped layer is a P-type doped layer, and the lower doped layer is an N-type doped layer.

[0204] The dielectric layer, the first dielectric layer, and the second dielectric layer can be one or more of oxides, nitrides, oxynitrides, halides, carbides, and silicon, and their thickness can be set as needed, for example, 0-10 nm. Preferably, the dielectric layer, the first dielectric layer, and the second dielectric layer can be one or more of silicon oxide, aluminum oxide, titanium oxide, niobium oxide, boron oxide, gallium oxide, tin oxide, hafnium oxide, tantalum oxide, silicon nitride, silicon oxynitride, silicon carbide, lithium fluoride, magnesium fluoride, amorphous silicon, microcrystalline silicon, nanocrystalline silicon, etc.

[0205] The insulating layer can be one or more of oxides, nitrides, oxynitrides, halides, carbides, and silicon, and its thickness can be set as needed, for example, 0-5000 nm. Preferably, the insulating layer can be one or more of phosphosilicate glass, borosilicate glass, aluminosilicate glass, gallium silicon glass, silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, silicon carbide, and amorphous silicon.

[0206] The surface passivation layer can be one or more of oxides, nitrides, oxynitrides, halides, carbides, and silicon, and its thickness can be set as needed, for example, 0-1000 nm. Preferably, the surface passivation layer can be one or more of silicon oxide, aluminum oxide, titanium oxide, niobium oxide, boron oxide, gallium oxide, tin oxide, hafnium oxide, tantalum oxide, indium oxide, tungsten oxide, zinc oxide, silicon nitride, silicon oxynitride, silicon carbide, lithium fluoride, magnesium fluoride, amorphous silicon, microcrystalline silicon, and nanocrystalline silicon.

[0207] The above brief description of each layer of materials also applies to the schemes described below in Implementation Scheme B and Implementation Scheme C.

[0208] 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.

[0209] A portion of the first doped layer and a portion of the second doped layer are electrically connected, forming a side mating surface. The direct or indirect contact, or partial direct or indirect overlap, between the two sides can be achieved through patterning of the first and second doped layers. Patterning can be achieved through laser etching and / or chemical etching. Direct contact refers to the direct contact of a local side of the first doped layer and a local side of the second doped layer; indirect contact refers to the indirect contact of a local side of the first doped layer and a local side of the second doped layer through a conductive film layer (e.g., a tunneling oxide layer). Direct overlap refers to a local stacking of the first and second doped layers with some areas in direct contact; indirect overlap refers to a local stacking of the first and second doped layers with some areas indirect contact through a conductive film layer (e.g., a tunneling oxide layer). Alternatively, an insulating film layer (i.e., an insulating film layer) can be introduced at the locations where the first and second doped layers directly or indirectly contact or overlap. The combination of a locally placed insulating film layer and the conductive film layer placed between them allows for adjustment of the electrical connection area of ​​the conductive connection structure 700. The film layer combination can be selected according to requirements.

[0210] The first bent structure 500 and the second bent structure 600 can be fabricated using laser etching and / or chemical etching. Laser etching allows for the determination of the shape of the protrusion in the bent structure by selecting the laser spot size, shape, and angle. For example, a square spot yields a square protrusion; an inclined square spot yields a triangular or trapezoidal protrusion; and a circular spot yields an arc-shaped protrusion. Chemical etching can be used in conjunction with masks, and the desired protrusion shape can be obtained by adjusting the concentration of the etching solution and the etching time. Alternatively, a combination of laser etching and chemical etching can be used. The fabrication methods for the first bent structure 500 and the second bent structure 600 can be the same or different. When the first and second bent structures differ significantly, using different fabrication methods is easier. The first and second bent structures can also be formed using existing back-contact battery fabrication processes to simplify the process. For example, a silicon glass layer generated during the fabrication of a doped polycrystalline silicon layer can be used as a mask. The silicon glass layer can be treated with a laser to form a pre-structure with the desired protrusion shape. Wet etching can be used to remove the doped polycrystalline silicon layer and part of the semiconductor substrate structure. By controlling the concentration of the reaction solution, the processing time, and the reaction temperature, a second bent structure can be further formed on the semiconductor substrate corresponding to the first bent structure. By selecting and setting the laser parameters, reaction solution, and reaction conditions according to requirements, the desired first bent structure 500 and second bent structure 600 can be obtained.

[0211] Implementation Plan B

[0212] This application provides a back contact battery 100, as shown in Figures 12 and 13. 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 conductive connection structure 700 is provided between a portion of the first doped layer 200 and a portion of the second doped layer 300, and each conductive connection structure 700 includes at least two side mating surfaces 400.

[0213] In the back contact battery 100 of this application embodiment, by having a conductive connection structure 700 between a portion of the first doped layer 200 and a portion of the second doped layer 300, 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 is beneficial for the back contact battery 100 to have a low reverse breakdown voltage when it is shaded, thereby reducing the risk of hot spots. By setting a single conductive connection structure 700 to include at least two side mating surfaces 400, on the one hand, when the size of a single conductive connection structure is fixed, the leakage channel contact area of ​​the single conductive connection structure 700 can be increased, enhancing the hot spot prevention function. On the other hand, dispersing the electrical connection points to at least two sides can disperse the heat points, avoid local overheating, and improve the effect of hot spot effect. In the overall scheme design, this design can reduce the total number of conductive connection structures 700, and ensure that the photovoltaic module has a high photoelectric conversion efficiency in the forward voltage region while improving the hot spot effect. By increasing the number of side contact surfaces, while keeping the total leakage channel contact area of ​​a single conductive connection structure 700 unchanged or slightly increased, the size of a single conductive connection structure 700 can be reduced, thus reducing the impact of the conductive connection structure 700 on the appearance and allowing for a larger design space for the back contact battery 100. Therefore, by adjusting the size of a single conductive connection structure 700, the total number of conductive connection structures 700, the arrangement, etc., a balance can be achieved between improving the hot spot effect and ensuring photoelectric conversion efficiency.

[0214] The conductive connection structure 700 is used to realize the electrical connection between a portion of the first doped layer 200 and a portion of the second doped layer 300, mainly serving as a hot spot prevention structure, and can also be called a hot spot prevention structure or a hot spot prevention conductive connection structure. A single battery cell may have one or more conductive connection structures 700, wherein a single conductive connection structure 700 may include at least two side mating surfaces 400. A single "battery cell" may be a whole battery cell, a half battery cell, or a battery cell of other specifications. It is understood that when a single battery cell has multiple conductive connection structures 700, all conductive connection structures 700 may each include at least two side mating surfaces 400, or only some conductive connection structures 700 may each include at least two side mating surfaces 400.

[0215] This application also provides a photovoltaic module (not shown in the figure), which includes a battery string formed by the aforementioned back contact battery 100 electrically connected 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.

[0216] The back contact battery 100 of this application embodiment will now be described in more detail with reference to the accompanying drawings.

[0217] The back contact battery 100 of this application embodiment will be described below with reference to FIG19.

[0218] Figure 19 is similar to Figure 8 in Embodiment A, also showing the strip portion 201 of the first doped layer 200, the strip portion 301 of the second doped layer 300, the corresponding doped regions, and the spacing region 190, etc., which will not be described again here. In Figure 19, there is a conductive connection structure 700 between a part of the first doped layer 200 and a part of the second doped layer 300. The "part of the first doped layer" can be a part of the main body portion 204 of the first doped layer, or all or part of the extension portion 203 of the first doped layer. The "part of the second doped layer" can be a part of the main body portion 304 of the second doped layer, or all or part of the extension portion 303 of the second doped layer.

[0219] 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. Alternatively, the first doped layer 200 may be formed on the semiconductor substrate 101, and the second doped layer 300 may be formed within the semiconductor substrate 101.

[0220] Specifically, when both the first doped layer 200 and the second doped layer 300 are formed within the semiconductor substrate 101, i.e., when the first doped layer 200 and the second doped layer 300, having a certain thickness, exist within the semiconductor substrate 101, the conductive connection structure 700 having at least two side mating surfaces 400 can be formed by overlapping a portion of the first doped layer 200 and a portion of the second doped layer 300, or by overlapping a portion of the first doped layer 200 and a portion of the second doped layer 300 at a first position and mating at a second position. Compared to side mating surfaces formed by overlapping, side mating surfaces formed by mating have higher electrical connection reliability, and a top mating surface may also be formed between the top surface of the lower doped layer and the bottom surface of the upper doped layer, thereby further improving the hot spot prevention effect. When both the first doped layer 200 and the second doped layer 300 are formed on the semiconductor substrate 101, the conductive connection structure 700 having at least two side mating surfaces 400 can be formed by overlapping a portion of the first doped layer 200 and a portion of the second doped layer 300 (as shown in Figures 12 to 14), or it can be formed by overlapping a portion of the first doped layer 200 and a portion of the second doped layer 300 at a first position and mating at a second position (as shown in Figures 17 and 18). 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, and the height of the semiconductor substrate 101 corresponding to the main body portion 204 of the first doped layer 200 is higher than the height of the semiconductor substrate 101 corresponding to the main body portion 304 of the second doped layer 300, the conductive connection structure 700 having at least two side mating surfaces 400 can be formed by overlapping all or part of the extension portion 303 of the second doped layer with a portion of the first doped layer, or it can be formed by overlapping all or part of the extension portion 303 of the second doped layer with a portion of the first doped layer at a first position and mating at a second position. There may be one or more of the aforementioned first and second positions.

[0221] Regarding the specific structure of the spacing region 190, 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.

[0222] Regarding the number of side mating surfaces 400 in a single conductive connection structure 700, a single conductive connection structure 700 may have at least two side mating surfaces 400, for example, a single conductive connection structure 700 may have two side mating surfaces 400 (see Figure 12), three side mating surfaces 400 (see Figure 15), four side mating surfaces 400, five side mating surfaces 400 (see Figure 17), six side mating surfaces 400, or even up to nine side mating surfaces 400 (see Figure 18), etc.

[0223] Regarding the contact method between a portion of the first doped layer 200 and a portion of the second doped layer 300, the portion of the first doped layer 200 and the portion of the second doped layer 300 can directly contact each other to form a conductive connection structure 700; the portion of the first doped layer 200 and the portion of the second doped layer 300 can also indirectly contact each other to form a conductive connection structure 700, 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.

[0224] The conductive connection structure 700 can be formed in the spacer region 190, the first doped region, the second doped region, the spacer region 190 and the first doped region, or the spacer region 190 and the second doped region. The side mating surface 400 in a single conductive connection structure 700 can be formed at the junction of the spacer region 190, the first doped region 191, the second doped region 192, the junction of the spacer region 190 and the first doped region 191 (also referred to as the junction of the spacer region 190 and the strip-shaped portion 201 of the first doped layer), or the junction of the spacer region 190 and the second doped region 192 (also referred to as the junction of the spacer region 190 and the strip-shaped portion 301 of the second doped layer).

[0225] In some implementations, referring to Figures 12 to 18, a spacer region 190 is provided between the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer; the first doped layer 200 further includes an extension portion 203 of the first doped layer, and the second doped layer 300 further includes an extension portion 303 of the second doped layer; the extension portions 203 and 303 of the first doped layer are electrically connected at the spacer region 190 to form a conductive connection structure 700, wherein a single conductive connection structure 700 includes at least two side mating surfaces 400. For Figure 19, a spacer region 190 is provided between the strip-shaped portion 201 of the first doped layer and the strip-shaped portion 301 of the second doped layer; the extension portions 203 and 303 of the first doped layer are electrically connected at the spacer region 190 to form a conductive connection structure 700, wherein a single conductive connection structure 700 includes at least two side mating surfaces 400.

[0226] When the extension 203 of the first doped layer and the extension 303 of the second doped layer are overlapped at the spacing region 190, a single conductive connection structure 700 includes at least two side mating surfaces 400. The conductivity type of the first doped layer 200 can be N-type, in which case the conductivity type of the second doped layer 300 is P-type; or, the conductivity type of the first doped layer 200 can also be P-type, in which case the conductivity type of the second doped layer 300 is N-type. Optionally, the upper doped layer is an N-type doped layer, and the lower doped layer is a P-type doped layer. That is, when all or part of the extension 203 of the first doped layer is above all or part of the extension 303 of the second doped layer, the first doped layer 200 is an N-type doped layer, and the conductivity type of the second doped layer is a P-type doped layer; and when all or part of the extension 303 of the second doped layer is above all or part of the extension 203 of the first doped layer, the second doped layer is an N-type doped layer, and the conductivity type of the first doped layer 200 is a P-type doped layer.

[0227] The width of the spacing region 190 can range from 10 to 5000 micrometers. The width of the spacing region 190 is its dimension in the direction perpendicular to its extension direction. For example, the width of the spacing region 190 can be 10 micrometers, 100 micrometers, 500 micrometers, 1000 micrometers, 2000 micrometers, 3000 micrometers, or 5000 micrometers.

[0228] The width of the conductive connection structure 700 can range from 20 to 2000 micrometers. The width of the conductive connection structure 700 is its dimension in the direction perpendicular to the extension direction of the spacing region 190. For example, the width of the conductive connection structure 700 can be 20 micrometers, 50 micrometers, 100 micrometers, 500 micrometers, 1000 micrometers, or 2000 micrometers.

[0229] The length of the conductive connection structure 700 can range from 50 to 1000 micrometers. The length of the conductive connection structure 700 is its dimension in the direction of extension parallel to the spacing region 190. For example, the length of the conductive connection structure 700 can be 50 micrometers, 80 micrometers, 100 micrometers, 300 micrometers, 500 micrometers, or 1000 micrometers.

[0230] To balance hot spot prevention performance and battery efficiency, the sum of the width and length of the conductive connection structure 700 can range from 100 to 3000 micrometers. For example, the sum of the width and length of the conductive connection structure 700 can be 100 micrometers, 500 micrometers, 1000 micrometers, 2000 micrometers, or 3000 micrometers. By limiting the sum of the width and length of the conductive connection structure 700 to the aforementioned range, excessively large length and width dimensions of the conductive connection structure 700 can be avoided, which would lead to an excessively large leakage contact area and affect battery efficiency. This allows for a better match between hot spot prevention performance and battery conversion efficiency.

[0231] The length of the extension 203 of the first doped layer can range from 50 to 3000 micrometers. The length of the extension 203 of the first doped layer is the dimension of the extension 203 of the first doped layer in the extension direction parallel to the spacer region 190. The length of the extension 203 of the first doped layer can be, for example, 50 micrometers, 100 micrometers, 500 micrometers, 1000 micrometers, 2000 micrometers, or 3000 micrometers.

[0232] The width of the extension 203 of the first doped layer can range from 50 to 3000 micrometers. The length of the extension 203 of the first doped layer is the dimension of the extension 203 of the first doped layer in the direction perpendicular to the extension direction of the spacer region 190. The width of the extension 203 of the first doped layer can be, for example, 50 micrometers, 100 micrometers, 500 micrometers, 1000 micrometers, 2000 micrometers, or 3000 micrometers.

[0233] The length of the extension 303 of the second doped layer can range from 50 to 3000 micrometers. The length of the extension 303 of the second doped layer is the dimension of the extension 303 of the second doped layer in the extension direction parallel to the spacer region 190. The length of the extension 303 of the second doped layer can be, for example, 50 micrometers, 100 micrometers, 500 micrometers, 1000 micrometers, 2000 micrometers, or 3000 micrometers.

[0234] The width of the extension 303 of the second doped layer can range from 50 to 3000 micrometers. The length of the extension 303 of the second doped layer is the dimension of the extension 303 of the second doped layer in the direction perpendicular to the extension direction of the spacer region 190. The width of the extension 303 of the second doped layer can be, for example, 50 micrometers, 100 micrometers, 500 micrometers, 1000 micrometers, 2000 micrometers, or 3000 micrometers.

[0235] Through testing, by including at least two side contact surfaces 400 in a single conductive connection structure 700, the number of heat spot prevention structures was reduced from 1500-2000 to 500-800. The ratio of the total area of ​​the side contact surfaces 400 to the area of ​​the back contact battery 100 was (102). -9 -10 -3 ): 1.

[0236] In some embodiments, the extensions 203 and 303 of the first doped layer are electrically connected at a spacer region 190 to form a conductive connection structure 700, wherein the extensions 203 and 303 of the first doped layer are staggered. In this case, a single conductive connection structure 700 includes two side mating surfaces 400. The staggered overlap of the extensions 203 and 303 of the first doped layer reduces fabrication difficulty and is beneficial for practical applications, allowing for an increase in the leakage channel contact area of ​​a single conductive connection structure 700 without excessively affecting fabrication efficiency. "Staggered overlap" at the spacer region means that a portion of the end of the extension 203 of the first doped layer and a portion of the end of the extension 303 of the second doped layer are overlapped at the spacer region. For example, if the extension 303 of the second doped layer is staggered over the extension 203 of the first doped layer, only a portion of two of the three sides of the end of the extension 203 of the first doped layer are covered by the extension 303 of the second doped layer. Viewed from the semiconductor substrate, the projections of the end of the first doped layer extension 203 and the end of the second doped layer extension 303 on the semiconductor substrate only partially overlap. Here, the specific length ratio of the end to the entire extension is not limited and can be adjusted as needed. Assume that the length of the first doped layer extension 203 in its extension direction is m1, and its width in the direction perpendicular to its extension direction is n1; the length of the second doped layer extension 303 in its extension direction is m2, and its width in the direction perpendicular to its extension direction is n2; where m1 and m2 can be the same or different; n1 and n2 can be the same or different. Figure 12 shows a structure with staggered overlap in the spacer region 190, where a single conductive connection structure 700 includes two side mating surfaces 400, namely a first side mating surface 401 and a second side mating surface 402. Both the first side mating surface 401 and the second side mating surface 402 are formed between the extensions 203 and 303 of the first doped layer. The extension direction of the first side mating surface 401 is parallel to the extension direction of the spacer region 190, while the extension direction of the second side mating surface 402 is perpendicular to the extension direction of the spacer region 190. Figure 13 is a schematic cross-sectional view of the back contact battery 100 with the side mating surfaces 400 of Figure 12 along the X direction in Figure 12. Figure 14 is a schematic cross-sectional view along the Y direction in Figure 12. Combining Figures 13 and 14, it can be seen that the extensions 203 and 303 of the first doped layer staggered overlap at the spacer region 190, thereby forming a conductive connection structure 700 including two side mating surfaces 400.

[0237] The "extension direction of the spacer region" defines the extension direction of the portion of the spacer region 190 that defines the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer. In FIG19, there is only one direction of the spacer region 190, which defines the extension direction of the main body portion 204 of the first doped layer (i.e., the strip-shaped portion 201 of the first doped layer) and the main body portion 304 of the second doped layer (i.e., the strip-shaped portion 301 of the second doped layer).

[0238] In other embodiments, the extensions 203 and 303 of the first doped layer are electrically connected at a spacer region 190 to form a conductive connection structure 700, wherein the extension 303 of the second doped layer overlaps the extension 203 of the first doped layer to achieve an overlap, and the length of the extension 303 of the second doped layer is greater than the length of the extension 203 of the first doped layer in the extension direction of the spacer region 190. In this case, a single conductive connection structure 700 includes three or more side mating surfaces 400. Overlapping the extensions 203 of the first doped layer and the extensions 303 of the second doped layer increases the processing difficulty compared to staggered overlap, since it is necessary to ensure that the length of the extension 303 of the second doped layer is greater than the length of the extension 203 of the first doped layer and that they overlap. However, it is more effective in increasing the contact area of ​​the leakage channel of a single conductive connection structure 700 and in improving the hot spot effect. In the spacer region 190, "overlapping" means that at spacer region 190, a partial area of ​​the end of the extension 303 of the second doped layer overlaps the entire area of ​​the end of the extension 203 of the first doped layer, forming an overlap. All three sides of the end of the extension 203 of the first doped layer are covered by the extension 303 of the second doped layer. Viewed from the semiconductor substrate, the projection of the end of the extension 303 of the second doped layer completely covers the projection of the end of the extension 203 of the first doped layer. Similar to the previous example, the specific length ratio of the end to the entire extension is not limited and can be adjusted as needed. Assume that the length of the extension 203 of the first doped layer in its extension direction is m1, and its width in the direction perpendicular to its extension direction is n1; the length of the extension 303 of the second doped layer in its extension direction is m2, and its width in the direction perpendicular to its extension direction is n2; where m1 and m2 can be the same or different; n2 > n1. Figure 15 shows a structure with overlapping sections covering the spacer region 190. Each conductive connection structure 700 includes three side mating surfaces 400: a first side mating surface 401, a second side mating surface 402, and a third side mating surface 403. These surfaces are formed between the extensions of the first doped layer 203 and the second doped layer 303. The first side mating surface 401 extends parallel to the extension direction of the spacer region 190, while the second and third side mating surfaces 402 and 403 extend perpendicular to the extension direction of the spacer region 190. The cross-sectional structure of the back contact battery 100 with the side mating surfaces 400 shown in Figure 15 along the X direction is the same as in Figure 13. Figure 16 shows a schematic cross-sectional structure along the Y direction in Figure 15.As can be seen from Figures 13 and 16, the extension 203 of the first doped layer and the extension 303 of the second doped layer overlap at the spacer region 190, thereby forming a conductive connection structure 700 including three side mating surfaces 400.

[0239] Furthermore, the end of the extension 303 of the second doped layer extends to the junction of the spacer region 190 and the main body 204 of the first doped layer. In this case, a single conductive connection structure 700 includes more than three side mating surfaces 400. In the case of overlapping, by extending the end of the extension 303 of the second doped layer to the junction of the spacer region 190 and the main body 204 of the first doped layer, the number of side mating surfaces 400 of a single conductive connection structure 700 can be further increased, thereby further increasing the leakage channel contact area of ​​the single conductive connection structure 700 and further improving the effect of hot spot effect. Figure 17 shows a structure in which the spacer region 190 overlaps and the end of the extension 303 of the second doped layer extends to the junction of the spacer region 190 and the main body 204 of the first doped layer. Each conductive connection structure 700 includes five side mating surfaces 400: a first side mating surface 401, a second side mating surface 402, a third side mating surface 403, a fourth side mating surface 404, and a fifth side mating surface 405. The first side mating surface 401, the second side mating surface 402, and the third side mating surface 403 are the second... The extension 303 of the doped layer is formed over and overlaps the extension 203 of the first doped layer. The fourth side mating surface 404 and the fifth side mating surface 405 are formed by mating between the end of the extension 303 of the second doped layer and the main body 204 of the first doped layer. The extension directions of the first side mating surface 401, the fourth side mating surface 404 and the fifth side mating surface 405 are parallel to the extension direction of the spacer region 190, and the extension directions of the second side mating surface 402 and the third side mating surface 403 are perpendicular to the extension direction of the spacer region 190.

[0240] Furthermore, the extension 303 of the second doped layer extends across the spacing region 190 and extends such that the end of the extension 303 of the second doped layer is covered by the body portion 204 of the first doped layer. In this case, a single conductive connection structure 700 includes more than five side mating surfaces 400. In the case of overlapping, by extending the extension 303 of the second doped layer across the spacing region 190 and extending it such that the end of the extension 303 of the second doped layer is covered by the main body 204 of the first doped layer, the number of side mating surfaces 400 of a single conductive connection structure 700 can be further increased, thereby further increasing the leakage channel contact area of ​​a single conductive connection structure 700 and further improving the effect of hot spot effect. At the same time, since the end of the extension 303 of the second doped layer is covered by the main body 204 of the first doped layer to form a stacked structure, in the subsequent metallization process, the first electrode and the extension 303 of the second doped layer (especially the part of the extension 303 of the second doped layer that constitutes the stacked structure) provided corresponding to the main body 204 of the first doped layer will obviously be spaced apart by the main body 204 of the first doped layer. Therefore, when printing the first electrode, there is no need to consider the relative position of the first electrode and the stacked structure, and there is no need to consider the alignment problem, which makes the processing efficiency higher. Figure 18 shows a structure where the spacer region 190 and the doped region overlap, wherein a single conductive connection structure 700 includes nine side mating surfaces 400, namely a first side mating surface 401, a second side mating surface 402, a third side mating surface 403, a fourth side mating surface 404, a fifth side mating surface 405, a sixth side mating surface 406, a seventh side mating surface 407, an eighth side mating surface 408, and a ninth side mating surface 409; wherein, the first side mating surface 401, the second side mating surface 402, and the third side mating surface 403 are formed by the extension 303 of the second doped layer overlapping the extension 203 of the first doped layer, and the fourth side mating surface 404, the fifth side mating surface 405, and the sixth side mating surface 406 are the main mating surfaces of the first doped layer. The first part of the body portion 204 is formed over the first part of the end of the extension portion 303 of the second doped layer. The seventh side mating surface 407, the eighth side mating surface 408, and the ninth side mating surface 409 are formed over the second part of the body portion 204 of the first doped layer, over the second part of the end of the extension portion 303 of the second doped layer. The extension directions of the first side mating surface 401, the fourth side mating surface 404, and the seventh side mating surface 407 are parallel to the extension direction of the spacer region 190. The extension directions of the second side mating surface 402, the third side mating surface 403, the fifth side mating surface 405, the sixth side mating surface 406, the eighth side mating surface 408, and the ninth side mating surface 409 are perpendicular to the extension direction of the spacer region 190.

[0241] It is understood that when the extension 203 of the first doped layer and the extension 303 of the second doped layer overlap in the spacer region 190, the end of the extension 303 of the second doped layer can be further extended to the boundary between the spacer region 190 and the main body 204 of the first doped layer. Alternatively, the extension 303 of the second doped layer can be further extended across the spacer region 190 and extended such that the end of the extension 303 of the second doped layer is covered by the main body 204 of the first doped layer. In this example, compared to overlapping in the spacer region 190, the number of side mating surfaces 400 of a single conductive connection structure 700 increases less, the effect on increasing the contact area of ​​the leakage channel of a single conductive connection structure 700 is weaker, and the effect on improving the hot spot effect is weaker.

[0242] In some implementations, referring to FIG20, a spacer region 190 is provided between the body portion 204 of the first doped layer and the body portion 304 of the second doped layer; the second doped layer 300 also includes an extension portion 303 of the second doped layer; the extension portion 303 of the second doped layer extends across the spacer region 190 and extends such that the end of the extension portion 303 of the second doped layer is covered by the body portion 204 of the first doped layer. In this case, a single conductive connection structure 700 includes three side mating surfaces 400. For FIG19, the first doped layer includes only the strip portion 201 of the first doped layer, while the second doped layer 300 includes the strip portion 301 of the second doped layer and the extension portion 303 of the second doped layer; a spacer region 190 is provided between the strip portion 201 of the first doped layer and the strip portion 301 of the second doped layer; and the extension portion 303 of the second doped layer extends across the spacer region 190 and extends such that the end of the extension portion 303 of the second doped layer is covered by the body portion 204 of the first doped layer. In this implementation, since only the extension portion needs to be provided in the second doped layer 300, the processing difficulty can be reduced, which is beneficial to practical applications. This allows the leakage channel contact area of ​​a single conductive connection structure 700 to be increased without excessively affecting the processing efficiency. At the same time, since the end of the extension portion 303 of the second doped layer is covered by the main body portion 204 of the first doped layer to form a stacked structure, in the subsequent metallization process, the first electrode provided corresponding to the main body portion 204 of the first doped layer and the extension portion 303 of the second doped layer (especially the part of the extension portion 303 of the second doped layer that constitutes the stacked structure) will obviously be separated by the main body portion 204 of the first doped layer. Therefore, when printing the first electrode, there is no need to consider the relative position of the first electrode and the stacked structure, and there is no need to consider the alignment problem, which makes the processing efficiency higher. Figure 20 shows a structure with overlapping doped regions, wherein a single conductive connection structure 700 includes three side mating surfaces: a first side mating surface 401, a second side mating surface 402, and a third side mating surface 403. The first side mating surface 401, the second side mating surface 402, and the third side mating surface 403 are all formed between the main body portion 204 of the first doped layer and the extension portion 303 of the second doped layer. The extension direction of the first side mating surface 401 is parallel to the extension direction of the spacer region 190, while the extension directions of the second side mating surface 402 and the third side mating surface 403 are perpendicular to the extension direction of the spacer region 190.

[0243] In Implementation Scheme A, the back contact battery 100 has already been described with reference to Figure 9, and the same content will not be repeated here. Implementation Scheme B can be understood by referring to the content of Implementation Scheme A, and the features in Implementation Scheme A can be used in combination with the features in Implementation Scheme B.

[0244] As before, the "extension direction of the spacer region" refers to the extension direction of the portion defining the main body 204 of the first doped layer and the main body 304 of the second doped layer of the spacer region 190. Therefore, in FIG9, there are multiple directions of spacer regions 190. For a given spacer region 190, its extension direction is the extension direction of the portion defining the main body 204 of the first doped layer and the main body 304 of the second doped layer. For example, at reference 901, the extension direction of the spacer region 190 is the extension direction of the connecting portion 202 of the first doped layer and the extension direction at the end of the strip-shaped portion 301 of the second doped layer; at reference 902, the extension direction of the spacer region 190 is the extension direction of the strip-shaped portion 201 of the first doped layer and the extension direction of the strip-shaped portion 301 of the second doped layer; at reference 903, the extension direction of the spacer region 190 is the extension direction of the connecting portion 302 of the second doped layer and the extension direction at the end of the connecting portion 202 of the first doped layer.

[0245] Similar to Figure 9, the extension 203 of the first doped layer in Figure 19 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.

[0246] Thus, in the conductive connection structure 700 between a portion of the first doped layer 200 and a portion of the second doped layer 300, the "part of the first doped layer" can be a portion of the strip portion 201 of the first doped layer, or all or a portion of the connecting portion 202 of the first doped layer, or all or a portion of the extension portion 203 of the first doped layer; the "part of the second doped layer" can be a portion of the strip portion 301 of the second doped layer, or all or a portion of the connecting portion 302 of the second doped layer, or all or a portion of the extension portion 303 of the second doped layer.

[0247] The positions of the first doped layer 200 and the second doped layer 300 relative to the semiconductor substrate 101, the specific structure of the spacer region 190, the number of side mating surfaces 400 of a single conductive connection structure 700, the contact method between a portion of the first doped layer 200 and a portion of the second doped layer 300, and the formation location of the conductive connection structure 700 are similar to those described above and will not be repeated here.

[0248] In some implementations, referring to Figures 12 to 18, a spacer region 190 is provided between the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer; the first doped layer 200 further includes an extension portion 203 of the first doped layer, and the second doped layer 300 further includes an extension portion 303 of the second doped layer; the extension portions 203 of the first doped layer and the extension portions 303 of the second doped layer are electrically connected at the spacer region 190 to form a conductive connection structure 700, wherein a single conductive connection structure 700 includes at least two side mating surfaces 400. For Figure 9, there are multiple spacer regions 190, and the conductive connection structure 700 can be formed in one or more of the multiple spacer regions 190 as needed.

[0249] In some embodiments, the extensions 203 and 303 of the first doped layer are electrically connected at a spacer region 190 to form a conductive connection structure 700, wherein the extensions 203 and 303 of the first doped layer are staggered. In this case, a single conductive connection structure 700 includes two side mating surfaces 400. The technical effect is similar to that described above and will not be repeated here.

[0250] In other embodiments, the extension 203 of the first doped layer and the extension 303 of the second doped layer are electrically connected at the spacer region 190 to form a conductive connection structure 700, wherein the extension 303 of the second doped layer covers the extension 203 of the first doped layer to achieve overlap, and the length of the extension 303 of the second doped layer is greater than the length of the extension 203 of the first doped layer in the extension direction of the spacer region 190. In this case, a single conductive connection structure 700 includes three or more side mating surfaces 400. The technical effects are similar to those described above and will not be repeated here.

[0251] Furthermore, the end of the extension 303 of the second doped layer extends to the junction of the spacer region 190 and the main body 204 of the first doped layer. In this case, a single conductive connection structure 700 includes more than three side mating surfaces 400. The technical effect is similar to that described above and will not be repeated here.

[0252] Furthermore, the extension 303 of the second doped layer extends across the spacing region 190 and extends such that the end of the extension 303 of the second doped layer is covered by the main body 204 of the first doped layer. In this case, a single conductive connection structure 700 includes more than five side mating surfaces 400. The technical effect is similar to that described above and will not be repeated here.

[0253] Similarly, when the extension portion 203 of the first doped layer and the extension portion 303 of the second doped layer overlap in the spacer region 190, the end of the extension portion 303 of the second doped layer may be further extended to the junction of the spacer region 190 and the main body portion 204 of the first doped layer. Alternatively, the extension portion 303 of the second doped layer may be further extended across the spacer region 190 and extended such that the end of the extension portion 303 of the second doped layer is covered by the main body portion 204 of the first doped layer.

[0254] In some embodiments, the side contact surface 400 of the back contact battery 100 of this application embodiment has a first bending structure 500, in other words, the side contact surface 400 is not a flat surface. Compared to a planar contact surface, the side contact surface 400 with the first bending 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.

[0255] In Implementation Scheme A, the relevant content of the first bending structure has been introduced with reference to Figure 5, and will not be repeated here. Implementation Scheme B can be understood by referring to the content of Implementation Scheme A, and the features in Implementation Scheme A can be used in combination with the features in Implementation Scheme B. The bending unfolded length L and the end straight line length D are the bending unfolded length and end straight line length of the second horizontal side, respectively. For example, in the example shown in Figure 15, 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 first bending structure 500. Specifically, the directions parallel to the backlight surface 112, the extension directions of the side mating surfaces 400, and the extension directions of the first bending structure 500 of the second side mating surface 402 and the third side mating surface 403 are the left-right directions in Figure 15, while the directions parallel to the backlight surface 112, the extension directions of the side mating surfaces 400, and the extension directions of the first bending structure 500 of the first side mating surface 401 are the up-down directions in Figure 15.

[0256] The overall structure of the back contact battery 100 according to an embodiment of this application will be described below with reference to FIG13.

[0257] As shown in Figure 13, 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 one side of the backlight surface 112 of the semiconductor substrate 101. The first doped layer 200 and the second doped layer 300 have opposite conductivity types. The extension portion 303 of the second doped layer overlaps the extension portion 203 of the first doped layer in the spacing region 190 to form a conductive connection structure 700. Each conductive connection structure 700 includes two side mating surfaces 400, and the two side mating surfaces 400 each have a first bending structure 500.

[0258] The back contact battery 100 shown in Figure 13 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 of the first doped layer 203 and the extension of the second doped layer 303, 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.

[0259] The fabrication method of the back contact battery 100 in this embodiment can refer to any existing method that can be used to fabricate the back contact battery 100, and is not limited here. The number of side contact surfaces included in a single conductive connection structure can be achieved by planning a patterned design of the first doped layer and the second doped layer. That is, by setting the retained and removed portions of the first and second doped layers, electrical connection is achieved on a predetermined side. For example, in Figure 10g), a single conductive connection structure includes two side contact surfaces by retaining a portion of extension in both the first and second doped layers within the spacer region, and staggering the extensions of the two layers; in Figure 10h, a portion of extension is retained in both the first and second doped layers within the spacer region, and the projection of one extension onto the semiconductor substrate surface falls completely into the extension direction of the other extension onto the semiconductor substrate surface. By projecting the extension of one component onto the semiconductor substrate surface, and ensuring that the projected area of ​​the extension of the other component onto the semiconductor substrate surface is smaller than the projected area of ​​the extension of the other component onto the semiconductor substrate surface, a single conductive connection structure comprising three side mating surfaces can be achieved. In Figure 10i), by retaining partial extensions in both the first and second doped layers within the spacer region, and ensuring that the projection of the extension of one component onto the semiconductor substrate surface completely falls within the projection of the extension of the other component onto the semiconductor substrate surface in the extension direction of the spacer region, and that the projected area of ​​the extension of one component onto the semiconductor substrate surface is smaller than the projected area of ​​the extension of the other component onto the semiconductor substrate surface, and that the extension of the other component is electrically connected to the side of the main body of one component, a single conductive connection structure comprising five side mating surfaces can be achieved. The electrical connection of the first and second doped layers and the fabrication of the first bending structure can be similarly described in Embodiment A.

[0260] Implementation Plan C

[0261] This application provides a back contact battery 100, as shown in Figures 21 and 22. 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 of the semiconductor substrate 101, and the conductivity types of the first doped layer 200 and the second doped layer 300 are opposite. A spacer region 190 is provided between the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer. The first doped layer 200 further includes an extension portion 203 of the first doped layer, which extends at least across a portion of the spacer region 190 and extends below the second doped layer 300. The extension portion 203 of the first doped layer and the second doped layer 300 are electrically connected.

[0262] In the back contact battery 100 of this application embodiment, by extending the extension 203 of the first doped layer at least across a portion of the spacing region 190 and extending below the second doped layer 300, a side mating surface 400 can be formed at the electrical connection between the first doped layer 200 and the second doped layer 300. The local electrical connection between doped layers of opposite conductivity types forms a built-in diode with a lower reverse breakdown voltage, which is beneficial to have 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. Since the extension 203 of the first doped layer extends below the second doped layer 300, in the subsequent metallization process, the second electrode 122 corresponding to the main body 304 of the second doped layer and the extension 203 of the first doped layer will obviously be spaced apart by the second doped layer 300. Therefore, when printing the second electrode 122, there is no need to consider the relative position of the second electrode 122 and the stacked structure 160, and there is no need to consider the alignment problem, which makes the processing efficiency higher. At the same time, it does not affect the current collection of the second electrode 122, and does not cause a short circuit between the second electrode 122 and the second doped layer 300.

[0263] The stacked structure 160 formed by the extension 203 of the first doped layer and the second doped layer 300 mainly serves as a heat-prevention structure, and can also be called a heat-prevention structure, a heat-prevention conductive connection structure, or a conductive connection structure. A single battery cell can have one or more stacked structures 160. A single "battery cell" can be a whole cell, a half cell, or a cell of other specifications.

[0264] This application also provides a photovoltaic module (not shown in the figure), which includes a battery string formed by the aforementioned back contact battery 100 electrically connected 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.

[0265] The back contact battery 100 of this application embodiment will now be described in more detail with reference to the accompanying drawings.

[0266] 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.

[0267] In some embodiments, the second doped layer 300 further includes an extension 303 of the second doped layer, and the extension 203 of the first doped layer extends at least across a portion of the spacing region 190 and extends below the extension 303 of the second doped layer. The extension 203 of the first doped layer and the extension 303 of the second doped layer are electrically connected to form a conductive connection structure 700. The electrical connection of the extensions avoids short circuits caused by the connection between the electrodes and electrical connection points of doped layers with different conductivity types during metallization.

[0268] In other embodiments, different sizes or numbers of side mating surfaces 400 can be obtained by adjusting the dimensions or coverage relationship of the extension portion 203 of the first doped layer and the extension portion 303 of the second doped layer. Specifically, the dimensions of the extension portion 203 of the first doped layer and the extension portion 303 of the second doped layer refer to their lengths in the extending direction of the spacer region 190. The "extending direction of the spacer region" refers to the extending direction of the portion defining the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer in the spacer region 190, which will be described in detail below with reference to Figures 28 and 29.

[0269] As shown in FIG30, in some embodiments, the extension 203 of the first doped layer extends across a portion of the spacer region 190 and extends below the extension 303 of the second doped layer. The extension 203 of the first doped layer and the extension 303 of the second doped layer are electrically connected to form a conductive connection structure 700, wherein, in the extension direction of the spacer region 190, the length of the extension 303 of the second doped layer is equal to the length of the extension 203 of the first doped layer. In this case, a single conductive connection structure 700 includes a side mating surface 400. The extension 203 of the first doped layer extends below the extension 303 of the second doped layer and both have the same length, so that the extension 303 of the second doped layer exactly covers and overlaps the extension 203 of the first doped layer. In other words, the entire area of ​​the end of the extension 303 of the second doped layer exactly covers the entire area of ​​the end of the extension 203 of the first doped layer, with a side mating surface formed only on the side of the end of the extension 203 of the first doped layer facing the extension 303 of the second doped layer. Viewed from the semiconductor substrate, the projection of the end of the extension 303 of the second doped layer onto the semiconductor substrate completely overlaps with the projection of the end of the extension 203 of the first doped layer onto the semiconductor substrate. Here, the specific length ratio of the end to the entire extension is not limited and can be adjusted as needed. By extending the extension 203 of the first doped layer below the extension 303 of the second doped layer and ensuring that both are of the same length, short circuits caused by the connection between the electrode and the electrical connection points of doped layers with different conductivity types during metallization are avoided. However, due to the need for precise alignment, this may present processing difficulties. Therefore, in some embodiments, the length of the extension 303 of the second doped layer is not equal to the length of the extension 203 of the first doped layer.

[0270] As shown in Figure 31, in some embodiments, the extension 203 of the first doped layer extends across a portion of the spacer region 190 and extends below the extension 303 of the second doped layer. The extension 203 of the first doped layer and the extension 303 of the second doped layer are electrically connected to form a conductive connection structure 700, wherein, in the extension direction of the spacer region 190, the length of the extension 303 of the second doped layer is less than the length of the extension 203 of the first doped layer. In this case, a single conductive connection structure 700 includes a side mating surface 400. The extension 203 of the first doped layer extends below the extension 303 of the second doped layer and is longer, so that the extension 303 of the second doped layer can only cover a portion of the end of the extension 203 of the first doped layer. In other words, the entire area of ​​the end of the extension 303 of the second doped layer covers the area above a partial area of ​​the end of the extension 203 of the first doped layer, and a side mating surface is formed only on the side of the end of the extension 203 of the first doped layer facing the extension 303 of the second doped layer. Viewed from the semiconductor substrate, the projection of the end of the extension 303 of the second doped layer onto the semiconductor substrate falls within the projection of the end of the extension 203 of the first doped layer onto the semiconductor substrate. Similarly, the specific length ratio of the end to the entire extension is not limited and can be adjusted as needed. By making the length of the extension 203 of the lower first doped layer longer, the electrical connection reliability at the overlap is higher, and it is easier to process.

[0271] As shown in Figure 32, in some embodiments, the extension 203 of the first doped layer extends across a portion of the spacer region 190 and extends below the extension 303 of the second doped layer. The extension 203 of the first doped layer and the extension 303 of the second doped layer are electrically connected to form a conductive connection structure 700, wherein, in the extension direction of the spacer region 190, the length of the extension 303 of the second doped layer is greater than the length of the extension 203 of the first doped layer. In this case, a single conductive connection structure 700 includes three side mating surfaces 400. The extension 203 of the first doped layer extends below the extension 303 of the second doped layer and the extension 303 of the second doped layer is longer, so that the extension 303 of the second doped layer can cover the entire portion of the end of the extension 203 of the first doped layer. In other words, a partial region of the end of the extension 303 of the second doped layer covers the entire region of the end of the extension 203 of the first doped layer, and all three sides of the end of the extension 203 of the first doped layer are covered by the extension 303 of the second doped layer. Viewed from the semiconductor substrate, the projection of the end of the extension 303 of the second doped layer completely covers the projection of the end of the extension 203 of the first doped layer. Similarly, the specific length ratio of the end to the entire extension is not limited and can be adjusted as needed. By making the length of the extension 303 of the upper second doped layer longer, a single conductive connection structure 700 can have three side mating surfaces. By configuring a single conductive connection structure 700 to include three side mating surfaces 400, on the one hand, when the size of the single conductive connection structure is fixed, the contact area of ​​the leakage channel of the single conductive connection structure 700 can be increased, enhancing the hot spot prevention function; on the other hand, dispersing the electrical connection points to at least two sides can disperse the heat source, avoid local overheating, and improve the hot spot effect. In the overall design, this design can reduce the total number of conductive connection structures 700, ensuring that the photovoltaic module has a high photoelectric conversion efficiency in the forward voltage region while improving the hot spot effect. By increasing the number of side contact surfaces, while keeping the total leakage channel contact area of ​​a single conductive connection structure 700 unchanged or slightly increased, the size of a single conductive connection structure 700 can be reduced, thus reducing the impact of the conductive connection structure 700 on the appearance and allowing for a larger design space for the back contact battery 100. Therefore, by adjusting the size of a single conductive connection structure 700, the total number of conductive connection structures 700, the arrangement, etc., a balance can be achieved between improving the hot spot effect and ensuring photoelectric conversion efficiency.

[0272] In other embodiments, the extension 203 of the first doped layer extends across the spacing region 190 and extends below the main body 304 of the second doped layer, and the extension 203 of the first doped layer and the main body 304 of the second doped layer are electrically connected. Thus, in subsequent metallization processes, the second electrode 122 corresponding to the main body 304 of the second doped layer and the extension 203 of the first doped layer (especially the portion of the extension 203 of the first doped layer that forms a stacked structure 160 with the main body 304 of the second doped layer) will obviously be spaced apart by the main body 304 of the second doped layer. Therefore, when printing the second electrode 122, there is no need to consider the relative position of the second electrode 122 and the stacked structure 160, and no alignment issues are required, resulting in higher processing efficiency. At the same time, it does not affect the current collection of the second electrode 122, nor does it cause a short circuit between the second electrode 122 and the second doped layer 300.

[0273] In the back contact battery 100 of this application embodiment, the extension 203 of the first doped layer extends below the main body 304 of the second doped layer, that is, the main body 304 of the second doped layer covers the portion of the extension 203 of the first doped layer located below the main body 304 of the second doped layer, and a stacked structure 160 having at least two side mating surfaces 400 is formed between the extension 203 of the first doped layer and the main body 304 of the second doped layer. The stacked structure 160 has at least two side contact surfaces 400. On the one hand, when the size of a single stacked structure 160 is fixed, the contact area of ​​the leakage current channel of the single stacked structure 160 can be increased, enhancing the hot spot prevention function. On the other hand, distributing the electrical connection points to at least two sides can disperse the heat points, avoid local overheating, and improve the hot spot effect. In the overall design, this design can reduce the total number of stacked structures 160, ensuring that the photovoltaic module has a high photoelectric conversion efficiency in the forward voltage region while improving the hot spot effect. By increasing the number of side contact surfaces 400, while keeping the total leakage current channel contact area of ​​a single stacked structure 160 unchanged or slightly increased, the size of a single stacked structure 160 can be reduced, reducing the impact of the stacked structure 160 on the appearance and allowing for a larger design space for the back contact cell 100. Thus, by adjusting the size of a single stacked structure 160, the total number of stacked structures 160, the arrangement, etc., a balance can be achieved between improving the hot spot effect and ensuring photoelectric conversion efficiency.

[0274] As mentioned above, the "first doped layer" and the "second doped layer" can be interchanged. For example, alternatively, the back contact battery 100 of this application embodiment may include: 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; there is a spacing region 190 between the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer; wherein, the second doped layer 300 further includes an extension portion 303 of the second doped layer, the extension portion 303 of the second doped layer extends across the spacing region 190 and extends below the main body portion 204 of the first doped layer, and the extension portion 303 of the second doped layer and the main body portion 204 of the first doped layer are electrically connected.

[0275] 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 28 and Figure 29 respectively.

[0276] Figure 28 is similar to the description in Implementation Scheme A with reference to Figure 8, and the similarities will not be repeated here. Implementation Scheme B can be understood by referring to the content of Implementation Scheme A, and the features in Implementation Scheme A can be used in combination with the features in Implementation Scheme C.

[0277] 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. The extension 203 of the first doped layer extends across the spacing region 190 and extends below the strip portion 301 of the second doped layer, such that the extension 203 of the first doped layer and the strip portion 301 of the second doped layer are electrically connected to form a stacked structure 160 having at least two side mating surfaces 400, as shown by 801 and 802 in FIG28.

[0278] Alternatively, 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 a local region of the strip portion 301 of the second doped layer toward the strip portion 201 of the first doped layer. The extension 303 of the second doped layer extends across the spacing region 190 and extends below the strip portion 201 of the first doped layer, such that the extension 303 of the second doped layer and the strip portion 201 of the first doped layer are electrically connected and form a stacked structure 160 having at least two side mating surfaces 400, as shown by 803 and 804 in FIG28.

[0279] Regarding the positions of the first doped layer 200 and the second doped layer 300 relative to the semiconductor substrate 101, when the extension 203 of the first doped layer extends below the main body 304 of the second doped layer, both the first doped layer 200 and the second doped layer 300 may be formed on the semiconductor substrate 101; or, 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. Alternatively, when the extension 303 of the second doped layer extends below the main body 204 of the first doped layer, both the first doped layer 200 and the second doped layer 300 may be formed on the semiconductor substrate 101; or, 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. Since "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, alternative solutions are also within the scope of protection of this application.

[0280] The specific structure of interval region 190 has been described in Implementation Scheme A and will not be repeated here. Implementation Scheme C can be understood by referring to the content of Implementation Scheme A, and the features in Implementation Scheme A can be used in combination with the features in Implementation Scheme C.

[0281] The aforementioned "extension direction of the spacer region" refers to the extension direction of the portion that defines the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer in the spacer region 190. Specifically, in FIG28, there is only one direction of the spacer region 190, which defines the extension direction of the main body portion 204 of the first doped layer (i.e., the strip-shaped portion 201 of the first doped layer) and the main body portion 304 of the second doped layer (i.e., the strip-shaped portion 301 of the second doped layer) in the spacer region 190.

[0282] Figure 29 is similar to Figure 9 in Embodiment A, also showing the strip-shaped portion 201 of the first doped layer 200, the strip-shaped portion 301 of the second doped layer 300, the corresponding doped regions, and the spacer region 190, etc. The same details will not be repeated here. Embodiment C can be understood by referring to the content of Embodiment A, and the features in Embodiment A can be used in combination with the features in Embodiment C.

[0283] The first doped layer 200 may further include an extension 203 of the first doped layer, which extends from a local area of ​​the main body portion 204 of the first doped layer toward the second doped layer 300, that is, from the strip 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 of the second doped layer, and the extension 203 of the first doped layer extends across the spacer region 190 and extends below the strip-shaped portion 301 of the second doped layer, such that the extension 203 of the first doped layer and the strip-shaped portion 301 of the second doped layer are electrically connected to form a stacked structure 160 having at least two side mating surfaces 400, as shown by markings 902 and 904 in FIG29; or, 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 connecting portion 302 of the second doped layer, and the extension 203 of the first doped layer extends across the spacer region 190 and extends below the connecting portion 302 of the second doped layer, such that the extension 203 of the first doped layer and the strip-shaped portion 2 ... The extension 203 of the first doped layer and the connection portion 302 of the second doped layer are electrically connected to form a stacked structure 160 having at least two side mating surfaces 400, as shown by reference numerals 903 and 905 in FIG29; or, the extension 203 of the first doped layer extends from all or part of the connection portion 202 of the first doped layer toward the strip portion 301 of the second doped layer (typically the end of the strip portion 301 of the second doped layer adjacent to the connection portion 202 of the first doped layer), and the extension 203 of the first doped layer extends across the spacing region 190 and extends below the strip portion 301 of the second doped layer, such that the extension 203 of the first doped layer and the strip portion 301 of the second doped layer are electrically connected to form a stacked structure 160 having at least two side mating surfaces 400, as shown by reference numeral 901 in FIG29.

[0284] Alternatively, 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, i.e., 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 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. The specific arrangement between the extension 303 of the second doped layer and the main body portion 204 of the first doped layer is similar to that described above and will not be repeated here.

[0285] As for the formation of the extension 203 of the first doped layer, the position of the first doped layer 200 and the second doped layer 300 relative to the semiconductor substrate 101, and the specific structure of the spacing region 190, they are similar to those described above and will not be repeated here.

[0286] The aforementioned "extension direction of the spacer region" refers to the extension direction of the portion defining the main body 204 of the first doped layer and the main body 304 of the second doped layer of the spacer region 190. Specifically, in FIG29, there are spacer regions 190 in multiple directions. For a certain spacer region 190, its extension direction is the extension direction of the portion defining the main body 204 of the first doped layer and the main body 304 of the second doped layer of the spacer region 190. For example, at mark 901, the extension direction of the spacer region 190 is the extension direction of the connecting portion 202 of the first doped layer and the extension direction at the end of the strip-shaped portion 301 of the second doped layer; at mark 902, the extension direction of the spacer region 190 is the extension direction of the strip-shaped portion 201 of the first doped layer and the extension direction of the strip-shaped portion 301 of the second doped layer; at mark 903, the extension direction of the spacer region 190 is the extension direction of the connecting portion 302 of the second doped layer and the extension direction at the end of the connecting portion 202 of the first doped layer. In Figure 29, O indicates the direction of extension of the interval region.

[0287] As mentioned above, the "first doped layer" and the "second doped layer" can be interchanged. In the following description, the structure of the back contact battery 100 of the present application embodiment will be described with the first doped layer 200 having an extension 203 of the first doped layer.

[0288] As described above, the extension 203 of the first doped layer extends across the spacer region 190 and extends below the main body 304 of the second doped layer, such that the extension 203 of the first doped layer and the main body 304 of the second doped layer are electrically connected to form a stacked structure 160 having at least two side mating surfaces 400.

[0289] Optionally, in the back contact battery 100 of this application embodiment, the electrical connection between the extension portion 203 of the first doped layer and the main body portion 304 of the second doped layer can form two side mating surfaces 400 or three side mating surfaces 400.

[0290] The number of side mating surfaces 400 formed depends on the position of the end of the extension 203 of the first doped layer relative to the main body 304 of the second doped layer. Specifically, when the end of the extension 203 of the first doped layer does not reach the downstream side of the main body 304 of the second doped layer (i.e., the end of the extension extends directly below the main body 304 of the second doped layer and terminates without exceeding the position of the main body 304 of the second doped layer), three side mating surfaces 400 can be formed between the extension 203 of the first doped layer and the main body 304 of the second doped layer, as shown in Figures 21 and 24; when the end of the extension 203 of the first doped layer reaches the downstream side of the main body 304 of the second doped layer, or extends beyond the downstream side of the main body 304 of the second doped layer, or extends beyond the downstream side of the main body 304 of the second doped layer and further extends to the upstream side of another main body 204 of the first doped layer adjacent to the main body 304 of the second doped layer, two side mating surfaces 400 are formed, as shown in Figures 26 and 27.

[0291] In this text, "upstream" and "downstream" are defined based on the first doped layer 200 having the extension portion 203 of the first doped layer, along the extension direction of the extension portion 203 of the first doped layer. For example, if the extension portion 203 of the first doped layer extends from a local region of the strip portion 201 of the first doped layer toward the strip portion 301 of the second doped layer, then the strip portion 301 of the second doped layer is downstream; and, for the strip portion 301 of the second doped layer itself, it has two sides in the extension direction of the extension portion 203 of the first doped layer, wherein the side closer to the strip portion 201 of the first doped layer is the upstream side of the strip portion 301 of the second doped layer, and the other side farther away from the strip portion 201 of the first doped layer is the downstream side of the strip portion 301 of the second doped layer. For example, if the extension 203 of the first doped layer extends from a local area of ​​the strip-shaped portion 201 of the first doped layer toward the connecting portion 302 of the second doped layer, then the connecting portion 302 of the second doped layer is downstream. Furthermore, the connecting portion 302 of the second doped layer itself has two sides in the extending direction of the extension 203 of the first doped layer, wherein the side closer to the strip-shaped portion 201 of the first doped layer is the upstream side of the connecting portion 302 of the second doped layer, and the other side farther from the strip-shaped portion 201 of the first doped layer is the downstream side of the connecting portion 302 of the second doped layer. As another example, if the extension 203 of the first doped layer extends from all or part of the connecting portion 202 of the first doped layer toward the end of the strip-shaped portion 301 of the second doped layer adjacent to the connecting portion 202 of the first doped layer, then the end of the strip-shaped portion 301 of the second doped layer adjacent to the connecting portion 202 of the first doped layer is downstream.

[0292] In some embodiments, the extension 203 of the first doped layer extends below the body portion 304 of the adjacent second doped layer, and its end extends below the body portion 304 of the second doped layer and terminates at a position not exceeding the body portion 304 of the second doped layer. In this case, three side mating surfaces 400 are formed between the extension 203 of the first doped layer and the body portion 304 of the second doped layer, as shown in Figures 21 and 24. By extending the end of the extension 203 of the first doped layer below the body portion 304 of the second doped layer and terminating at a position not exceeding the body portion 304 of the second doped layer, three side mating surfaces 400 can be formed, which increases the total leakage channel contact area, improves the effect of a single stacked structure 160 on hot spot effect, and reduces the total number of stacked structures 160. While improving the hot spot effect, it ensures that the photovoltaic module has a high photoelectric conversion efficiency in the forward voltage region. Furthermore, since the end of the extension 203 of the first doped layer only needs to extend below the body portion 304 of the second doped layer, the amount of material used is reduced, and the material cost is lowered.

[0293] A second electrode 122 is disposed above the second doped layer 300, and the second electrode 122 has a contact portion 1220 that contacts the second doped layer 300, as shown in Figures 22 and 25. Typically, the second electrode 122 may include a transport portion and a contact portion 1220, with the transport portion forming an electrical contact with the second doped layer 300 through the contact portion 1220. Similarly, the first electrode 121 may include a transport portion and a contact portion, with the transport portion forming an electrical contact with the first doped layer 200 through the contact portion. When the end of the extension 203 of the first doped layer extends below the main body 304 of the second doped layer, there are two cases distinguished by the different relative positions of the projections of the end of the extension 203 of the first doped layer and the contact portion 1220 of the second electrode 122. In the first case, the end of the extension 203 of the first doped layer does not extend beyond the projection of the contact portion 1220 of the second electrode 122; in other words, the end of the extension 203 of the first doped layer does not extend beyond the downstream side of the projection of the contact portion 1220 of the second electrode 122, as shown in Figures 21 and 22. In the second case, the end of the extension 203 of the first doped layer extends beyond the projection of the contact portion 1220 of the second electrode 122; in other words, the end of the extension 203 of the first doped layer has a portion that extends beyond the downstream side of the projection of the contact portion 1220 of the second electrode 122, as shown in Figures 24 and 25. "Projection of the contact portion of the second electrode" is the projection of the contact portion 1220 of the second electrode 122 onto the semiconductor substrate 101; and, in the extension direction of the extension portion 203 of the first doped layer, the projection of the contact portion 1220 of the second electrode 122 has an upstream side and a downstream side. The relative position of the end of the extension portion 203 of the first doped layer and the projection of the contact portion 1220 of the second electrode 122 specifically refers to the relative position of the end of the extension portion 203 of the first doped layer and the downstream side of the projection of the contact portion 1220 of the second electrode 122.

[0294] Referring to Figure 21, in some embodiments, in the extension direction of the first doped layer extension 203, the distance between the end of the first doped layer extension 203 and the upstream side of the projection of the contact portion 1220 of the second electrode 122 is W1, where W1 > 0. The existence of a distance W1 > 0 between the end of the first doped layer extension 203 and the upstream side of the projection of the contact portion 1220 of the second electrode 122 indicates a gap between them. This allows the collected leakage current to be quickly conducted away through the electrode, shortening the leakage current transmission path and further improving the hot spot prevention effect. It also further reduces material usage and lowers material costs. Assuming the width of the second doped layer 300 in the extension direction of the first doped layer extension 203 is W3 (not shown in the figure), W1 can be ≤ 1 / 2W3. Typically, W3 ∈ (30 micrometers - 1000 micrometers). W3 can be, for example, 30 micrometers, 100 micrometers, 400 micrometers, 800 micrometers, or 1000 micrometers. Optionally, 1000 micrometers > W1 > 30 micrometers. W1 can be, for example, 35 micrometers, 50 micrometers, 100 micrometers, 150 micrometers, 200 micrometers, 500 micrometers, or 900 micrometers. Setting W1 to be greater than 30 micrometers ensures connection reliability, while setting W1 to be less than 1000 micrometers prevents excessive leakage area of ​​a single heat-resistant structure, which could affect forward power generation efficiency.

[0295] Referring again to Figure 21, the width of the spacer region 190 in the extension direction of the extension 203 of the first doped layer is W2, where W2 > W1. By setting W2 > W1, the leakage current of the back contact cell 100 under normal operating conditions can be reduced, further ensuring that the photovoltaic module has a high photoelectric conversion efficiency in the forward voltage region. W2 should be as large as possible, typically W2 ≤ 1000 micrometers. Typically, W2 ∈ (35 micrometers - 1000 micrometers). For example, W2 is 35 micrometers, 100 micrometers, 400 micrometers, 500 micrometers, or 1000 micrometers.

[0296] Specifically, in Figure 21, the extension 203 of the first doped layer extends below the main body 304 of the adjacent second doped layer, with its end extending below the main body 304 of the second doped layer. Furthermore, in the extension direction of the first doped layer extension 203, the distance W1 between the end of the first doped layer extension 203 and the upstream side of the projection of the contact portion 1220 of the second electrode 122 is greater than 0. Three side mating surfaces 400 are formed between the first doped layer extension 203 and the main body 304 of the second doped layer, including a first side mating surface 401, a second side mating surface 402, and a third side mating surface 403. The extension directions of the first side mating surface 401 and the second side mating surface 402 are parallel to the extension direction of the first doped layer extension 203, while the extension direction of the third side mating surface 403 is perpendicular to the extension direction of the first doped layer extension 203. W1 is the distance between the point or line on the upstream side of the projection of the contact portion 1220 closest to the second electrode 122 among the three side mating surfaces 400 and the upstream side of the projection of the contact portion 1220 of the second electrode 122. In Figure 21, W1 is the distance between the third side mating surface 403 and the upstream side of the projection of the contact portion 1220 of the second electrode 122. Figure 22 is a schematic cross-sectional view along the X direction in Figure 21, showing the third side mating surfaces 403, W1, and W2, wherein the contact portion 1220 of the second electrode 122 is offset relative to the stacked structure 160. Figure 23 is a schematic cross-sectional view along the Y direction in Figure 21, showing the first side mating surface 401 and the second side mating surface 402.

[0297] The width of the main body portion 204 of the first doped layer in the extension direction of the extension portion 203 of the first doped layer is W4 (not shown in the figure), typically W4 ∈ (30 micrometers-1000 micrometers). W4 is, for example, 30 micrometers, 100 micrometers, 400 micrometers, 800 micrometers, and 1000 micrometers.

[0298] The effective electrical doping concentration of the extension 203 of the first doped layer at the spacer region 190 is typically less than 1E20cm⁻¹. -3 Preferably, it is less than 1E19cm. -3 This effectively reduces the electrical connection current between the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer, thereby reducing reverse leakage current and improving the photoelectric conversion efficiency of the battery. By adjusting the effective electrical doping concentration and the total leakage channel contact area of ​​the side contact surface 400, a balance can be achieved between improving the hot spot effect and ensuring photoelectric conversion efficiency. The effective electrical doping concentration of the extension portion 203 of the first doped layer at the spacing region 190 is, for example, 1E19cm³. -3 1E18cm -3 1E17cm -3 1E16cm-3 1E15cm -3 .

[0299] Referring to FIG. 24, in some embodiments, the end of the extension 203 of the first doped layer extends below the main body 304 of the second doped layer and extends beyond the projection of the contact portion 1220 of the second electrode 122. Compared with the scheme in FIG. 21, the scheme in FIG. 24 increases the amount of material used and the leakage current transmission path increases, but the processing efficiency is higher because there is no need to strictly control the relative position between the end of the extension 203 of the first doped layer and the contact portion 1220 of the second electrode 122.

[0300] Specifically, in Figure 24, the extension 203 of the first doped layer extends below the adjacent main body 304 of the second doped layer, with its end extending below the main body 304 of the second doped layer and beyond the projection of the contact portion 1220 of the second electrode 122. Three side mating surfaces 400 are formed between the extension 203 of the first doped layer and the main body 304 of the second doped layer, including a first side mating surface 401, a second side mating surface 402, and a third side mating surface 403. The extending directions of the first side mating surface 401 and the second side mating surface 402 are parallel to the extending direction of the extension 203 of the first doped layer, while the extending direction of the third side mating surface 403 is perpendicular to the extending direction of the extension 203 of the first doped layer. Figure 25 is a schematic cross-sectional view along the X direction in Figure 24, showing the third side mating surface 403, where the contact portion 1220 of the second electrode 122 is located above the stacked structure 160. In addition, the second electrode 122 may have multiple contact portions 1220, such as two contact portions 1220, one of which is above the stacked structure 160 and the other contact portion 1220 is biased relative to the stacked structure 160.

[0301] In other embodiments, the extension 203 of the first doped layer extends below the body portion 304 of the adjacent second doped layer, and its end extends beyond the downstream side of the body portion 304 of the second doped layer. In this case, two side mating surfaces 400 are formed between the extension 203 of the first doped layer and the body portion 304 of the second doped layer. Compared with forming three side mating surfaces 400, although the number of side mating surfaces 400 is reduced, the total leakage channel contact area can still be increased because the length of a single side mating surface 400 in the extension direction of the extension 203 of the first doped layer is increased. The single stacked structure 160 is more effective in improving the hot spot effect, thereby reducing the total number of stacked structures 160. This ensures that the photovoltaic module has a high photoelectric conversion efficiency in the forward voltage region while improving the hot spot effect.

[0302] Based on the first doped layer 200 with the extension 203 of the first doped layer (which can also be referred to as the upstream first doped layer), the main body 304 of the second doped layer may also have another main body 204 of the first doped layer downstream of the extension 203 of the first doped layer (which can also be referred to as the downstream first doped layer), as shown in Figures 26 and 27. When the end of the extension 203 of the first doped layer extends beyond the downstream side of the main body 304 of the second doped layer, there are two cases distinguished by whether the end of the extension 203 of the first doped layer reaches the main body 204 of the other first doped layer. In the first case, the end of the extension 203 of the first doped layer does not reach the main body 204 of the other first doped layer. In this case, the end of the extension 203 of the first doped layer is located in the downstream gap region 190 between the main body 304 of the second doped layer and the main body 204 of the downstream first doped layer, as shown in Figure 26. In the second case, the end of the extension 203 of the first doped layer reaches the main body 204 of another first doped layer. In this case, the end of the extension 203 of the first doped layer reaches at least the upstream side of the main body 204 of the downstream first doped layer, as shown in FIG27.

[0303] Referring to FIG. 27, in some embodiments, an extension 203 of a first doped layer extends below the body portion 304 of an adjacent second doped layer, with its end extending beyond the downstream side of the body portion 304 of the second doped layer, and further extending to the upstream side of the body portion 204 of another first doped layer adjacent to the body portion 304 of the second doped layer. In this case, the two body portions 204 of the first doped layers upstream and downstream of the body portion 304 of the second doped layer are connected by the extension 203 of the first doped layer, thereby allowing the leakage current collected at the side mating surface 400 of the stacked structure 160 to be quickly transmitted to both sides and then conducted away through the electrodes on both sides, shortening the transmission path of the leakage current and further improving the hot spot prevention effect.

[0304] Specifically, in Figure 27, the extension 203 of the upstream first doped layer extends below the main body 304 of the adjacent second doped layer, and its end extends beyond the downstream side of the main body 304 of the second doped layer, and further extends to the upstream side of the main body 204 of the downstream first doped layer adjacent to the main body 304 of the second doped layer. Two side mating surfaces 400 are formed between the extension 203 of the first doped layer and the main body 304 of the second doped layer, including a first side mating surface 401 and a second side mating surface 402. The extending directions of the first side mating surface 401 and the second side mating surface 402 are parallel to the extending direction of the extension 203 of the first doped layer.

[0305] Referring to FIG. 26, in some embodiments, the extension 203 of the first doped layer extends below the body portion 304 of the adjacent second doped layer, and its end extends beyond the downstream side of the body portion 304 of the second doped layer, but does not reach the body portion 204 of the other first doped layer. Compared with the scheme in FIG. 27, the scheme in FIG. 26 reduces the leakage current transmission speed, but reduces the amount of material used and the material cost.

[0306] Specifically, in Figure 26, the extension 203 of the first doped layer extends below the main body 304 of the adjacent second doped layer, and its end extends beyond the downstream side of the main body 304 of the second doped layer, but does not reach the main body 204 of the other first doped layer. Two side mating surfaces 400 are formed between the extension 203 of the first doped layer and the main body 304 of the second doped layer, including a first side mating surface 401 and a second side mating surface 402. The extending directions of the first side mating surface 401 and the second side mating surface 402 are parallel to the extending direction of the extension 203 of the first doped layer.

[0307] Referring now to Figures 28 and 29, several examples of the back contact battery 100 of this application embodiment will be described.

[0308] In Figure 28, at mark 801, the extension 203 of the first doped layer extends below the body portion 304 of the adjacent second doped layer, and its end extends below the body portion 304 of the second doped layer; at mark 802, the extension 203 of the first doped layer extends beyond the downstream side of the body portion 304 of the second doped layer, and its end further extends to the upstream side of the body portion 204 of another first doped layer adjacent to the body portion 304 of the second doped layer; at mark 803, the extension 303 of the second doped layer extends below the body portion 204 of the adjacent first doped layer, and its end extends below the body portion 204 of the first doped layer; at mark 804, the extension 303 of the second doped layer extends beyond the downstream side of the body portion 204 of the first doped layer, and its end further extends to the upstream side of the body portion 304 of another second doped layer adjacent to the body portion 204 of the first doped layer.

[0309] In Figure 29, at mark 901, the extension 203 of the first doped layer (which extends from the connecting portion 202 of the first doped layer toward the end of the strip-shaped portion 301 of the adjacent second doped layer) extends below the end of the strip-shaped portion 301 of the adjacent second doped layer, and its end extends below the strip-shaped portion 301 of the second doped layer; at mark 902, the extension 203 of the first doped layer (which extends from the strip-shaped portion 201 of the first doped layer toward the strip-shaped portion 301 of the adjacent second doped layer) extends below the strip-shaped portion 301 of the adjacent second doped layer, and its end extends below the strip-shaped portion 301 of the second doped layer; at mark 903, the extension 203 of the first doped layer (which extends from the end of the strip-shaped portion 201 of the first doped layer toward the connecting portion 302 of the adjacent second doped layer) extends below the end of the strip-shaped portion 301 of the adjacent second doped layer, and its end extends below the strip-shaped portion 301 of the second doped layer; The first doped layer extension 203 (which extends from the strip portion 201 of the upstream first doped layer toward the strip portion 301 of the adjacent second doped layer) extends below the strip portion 301 of the adjacent second doped layer, and its end extends to the strip portion 201 of the downstream first doped layer downstream of the strip portion 301 of the second doped layer; at mark 904, the first doped layer extension 203 (which extends from the end of the strip portion 201 of the upstream first doped layer toward the connection portion 302 of the adjacent second doped layer) extends below the connection portion 302 of the adjacent second doped layer, and its end extends to the end of the strip portion 201 of the downstream first doped layer downstream of the connection portion 302 of the second doped layer.

[0310] In some embodiments, the side contact surface 400 of the back contact battery 100 of this application embodiment has a bent structure 500; in other words, the side contact surface 400 is not a flat surface. When there are multiple side contact surfaces, one or more of them may have a bent structure 500. In the back contact battery 100 of this application embodiment, compared with a planar contact surface, the 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 the battery conversion efficiency loss caused by PN region contact while improving the hot spot effect.

[0311] For example, in the example shown in Figure 21, 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 21, 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 21.

[0312] The overall structure of the back contact battery 100 according to an embodiment of this application will be described below with reference to FIG22.

[0313] As shown in Figure 22, 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 one side of the backlight surface 112 of the semiconductor substrate 101. The first doped layer 200 and the second doped layer 300 have opposite conductivity types. There is a gap region 190 between the main body portion 204 of the first doped layer and the main body portion 304 of the second doped layer. The first doped layer 200 also includes an extension portion 203 of the first doped layer, which extends across the gap region 190 and extends below the main body portion 304 of the second doped layer. The extension portion 203 of the first doped layer and the main body portion 304 of the second doped layer are electrically connected.

[0314] The back contact battery 100 shown in Figure 22 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 of the first doped layer 203 and the extension of the second doped layer 303, 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.

[0315] The fabrication method of the back contact battery 100 in this embodiment can refer to any existing method that can be used to fabricate the back contact battery 100, and is not limited thereto. To ensure that the extension 203 of the first doped layer extends at least across a portion of the spacing region 190 and extends below the second doped layer 300, this can be achieved by first fabricating the first doped layer, retaining the extension at a predetermined location during the patterning of the first doped layer, and then fabricating the second doped layer. The electrical connection between the first and second doped layers and the fabrication of the first bending structure can be similarly referred to the description in Embodiment A.

[0316] Implementation Plan D

[0317] The preceding sections, Implementation Scheme A, Implementation Scheme B, and Implementation Scheme C, described some features of the back-contact battery. It should be understood that Implementation Scheme A, Implementation Scheme B, and Implementation Scheme C can be implemented individually, and some or all features of Implementation Scheme A, some or all features of Implementation Scheme B, and some or all features of Implementation Scheme C can also be used in combination, provided that such combinations are technically feasible.

[0318] 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 bent structure, it can be obtained using existing laser etching, chemical etching, or other methods; for example, using laser etching, the specific shape or structure of the bent structure can be controlled by controlling the spot size, etc.; or, for example, using chemical etching, the specific shape or structure of the bent structure can be controlled by adjusting the composition, concentration, and processing time of the chemical reagent, etc. Typically, the first bent structure can be formed using laser etching, and the specific structure of the first bent structure can be controlled by controlling the spot size, etc.; the second bent structure can be formed using chemical etching, and the specific structure of the second bent structure can be controlled by controlling the composition of the etching solution, the ratio between the components, the etching time, etc. The electrical connection between the first doped layer and the second doped layer, and the fabrication of the first bent structure, can be similarly referred to the description in Embodiment A.

[0319] Although this application is defined in the claims, it should be understood that it may be defined alternatively according to the following embodiments:

[0320] Example 1. A back contact battery, wherein the back contact battery includes: a semiconductor substrate, a first doped layer, and a second doped layer;

[0321] The main body portions of the first doped layer and the main body portions of the second doped layer are alternately distributed on one side of the backlight surface of the semiconductor substrate, and the conductivity types of the first doped layer and the second doped layer are opposite; wherein a portion of the first doped layer and a portion of the second doped layer have a conductive connection structure, and wherein a single conductive connection structure includes at least two side mating surfaces.

[0322] Example 2. According to the back contact battery of Example 1, there is a gap region between the main body of the first doped layer and the main body of the second doped layer; 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, and the extensions of the first doped layer and the extensions of the second doped layer are electrically connected at the gap region to form a conductive connection structure.

[0323] Example 3. The back contact battery according to Example 2, wherein the extensions of the first doped layer and the extensions of the second doped layer are staggered.

[0324] Example 4. The back contact battery according to Example 2, wherein the extension of the second doped layer covers the extension of the first doped layer to achieve overlap, and in the extension direction of the spacer region, the length of the extension of the second doped layer is greater than the length of the extension of the first doped layer.

[0325] Example 5. The back contact battery according to Example 4, wherein the end of the extension of the second doped layer extends to the junction of the spacer region and the main body of the first doped layer.

[0326] Example 6. The back contact battery according to Example 5, wherein the extension of the second doped layer extends across the spacing region and extends such that the end of the extension of the second doped layer is covered by the main body of the first doped layer.

[0327] Example 7. A back contact battery according to Example 1, wherein a spacer region is provided between the main body portion of the first doped layer and the main body portion of the second doped layer; the second doped layer further includes an extension portion of the second doped layer; the extension portion of the second doped layer extends across the spacer region and extends such that the end of the extension portion of the second doped layer is covered by the main body portion of the first doped layer.

[0328] Example 8. The back contact battery according to Example 1, wherein the side contact surface has a first bending structure; the first bending structure includes a plurality of contact sections that are bent and connected in a direction parallel to the backlight surface.

[0329] Example 9. The back contact battery according to Example 8, wherein each docking segment has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1; in a direction perpendicular to the extension direction of the first bending structure, the first bending structure has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1; wherein, 0.00005≤T1 / δ1≤500000.

[0330] Example 10: A photovoltaic module, wherein the photovoltaic module includes: a battery string formed by electrically connecting a plurality of back-contact batteries as in any one of Examples 1-9; and an encapsulation layer covering the surface of the back-contact batteries.

[0331] Example 11: A back contact battery, wherein the back contact battery includes: a semiconductor substrate, a first doped layer, and a second doped layer;

[0332] The main body portion of the first doped layer and the main body portion of the second doped layer are alternately distributed on one side of the back surface of the semiconductor substrate, and the conductivity types of the first doped layer and the second doped layer are opposite; 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; wherein, the first doped layer further includes an extension portion of the first doped layer, the extension portion of the first doped layer extends at least across a portion of the gap region and extends below the second doped layer, and the extension portion of the first doped layer and the second doped layer are electrically connected.

[0333] Example 12. The back contact battery according to Example 11, wherein the second doped layer further includes an extension of the second doped layer, the extension of the second doped layer extending at least across a portion of the spacing region, and the extension of the first doped layer and the extension of the second doped layer are electrically connected to form a conductive connection structure.

[0334] Example 13. The back contact battery according to Example 12, wherein, in the extending direction of the spacer region, the length of the extension of the first doped layer of at least one conductive connection structure is equal to the length of the extension of the second doped layer; and / or, in the extending direction of the spacer region, the length of the extension of the first doped layer of at least one conductive connection structure is greater than the length of the extension of the second doped layer; and / or, in the extending direction of the spacer region, the length of the extension of the first doped layer of at least one conductive connection structure is less than the length of the extension of the second doped layer.

[0335] Example 14. A back contact battery according to Example 11, wherein an extension of the first doped layer extends across the spacer region and extends below the main body of the second doped layer, and the extension of the first doped layer and the main body of the second doped layer are electrically connected.

[0336] Example 15. The back contact battery according to Example 14, wherein the extension of the first doped layer extends below the main body of the adjacent second doped layer, and the end extends below the main body of the second doped layer and terminates at a position not exceeding the main body of the second doped layer.

[0337] Example 16. According to the back contact battery of Example 15, a second electrode is disposed above the second doped layer; in the extending direction of the extension of the first doped layer, the distance between the end of the extension of the first doped layer and the upstream side of the projection of the contact portion of the second electrode is W1, wherein W1 > 0.

[0338] Example 17. The back contact battery according to Example 16, wherein the width of the spacer region in the extension direction of the extension of the first doped layer is W2, wherein W2 > W1.

[0339] Example 18. The back contact battery according to Example 11, wherein the extension of the first doped layer extends below the main body of the adjacent second doped layer, and the end extends beyond the downstream side of the main body of the second doped layer.

[0340] Example 19. A back contact battery according to Example 14, wherein an extension of a first doped layer extends below the body portion of an adjacent second doped layer, and its end extends beyond the downstream side of the body portion of the second doped layer, and its end further extends to the upstream side of the body portion of another first doped layer adjacent to the body portion of the second doped layer.

[0341] Example 20. A back contact battery according to Example 11, wherein the main body of the first doped layer includes a strip-shaped portion of the first doped layer, and the main body of the second doped layer includes a strip-shaped portion of the second doped layer; wherein an extension of the first doped layer extends from a local region of the strip-shaped portion of the first doped layer toward the strip-shaped portion of the second doped layer, and the extension of the first doped layer extends across the interval region and extends below the strip-shaped portion of the second doped layer, and the extension of the first doped layer and the strip-shaped portion of the second doped layer are electrically connected.

[0342] Example 21. A back contact battery according to Example 11, wherein the main body of the first doped layer includes a strip-shaped portion of the first doped layer and a connecting portion of the first doped layer, wherein the connecting portion of the first doped layer is used to connect multiple strip-shaped portions of the first doped layer; the second doped layer includes a strip-shaped portion of the second doped layer and a connecting portion of the second doped layer, wherein the connecting portion of the second doped layer is used to connect multiple strip-shaped portions of the second doped layer; wherein the back contact battery further includes one or more of the following structures: an extension of the first doped layer extends from a local region of the strip-shaped portion of the first doped layer toward the strip-shaped portion of the second doped layer, and the extension of the first doped layer extends across the spacing region and into the second doped layer. The first doped layer extends below the strip-shaped portion, and the extension portion of the first doped layer and the strip-shaped portion of the second doped layer are electrically connected; the extension portion of the first doped layer extends from a local area of ​​the strip-shaped portion of the first doped layer toward the connecting portion of the second doped layer, and the extension portion of the first doped layer extends across the gap region and extends below the connecting portion of the second doped layer, and the extension portion of the first doped layer and the connecting portion of the second doped layer are electrically connected; the extension portion of the first doped layer extends from all or part of the connecting portion of the first doped layer toward the strip-shaped portion of the second doped layer, and the extension portion of the first doped layer extends across the gap region and extends below the strip-shaped portion of the second doped layer, and the extension portion of the first doped layer and the strip-shaped portion of the second doped layer are electrically connected.

[0343] Example 22. The back contact battery according to Example 11, wherein the extension of the first doped layer and the second doped layer form a stacked structure having at least two side mating surfaces.

[0344] Example 23. The back contact battery according to Example 22, wherein the side contact surface has a bent structure; the bent structure includes multiple contact sections that are bent and connected in a direction parallel to the backlight surface.

[0345] Example 24. The back contact battery according to Example 23, wherein each docking segment has a protrusion, and the distance between the maximum points of two adjacent protrusions is T1; in a direction perpendicular to the extension direction of the bending structure, the bending structure has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1; wherein, 0.00005≤T1 / δ1≤500000.

[0346] Example 25: A photovoltaic module, wherein the photovoltaic module includes: a battery string formed by electrically connecting a plurality of back-contact batteries as in any of Examples 11-24; and an encapsulation layer covering the surface of the battery string.

[0347] 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.

[0348] 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.

[0349] 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.

Claims

1. A back-contact battery, comprising: Semiconductor substrate, first doped layer, and second doped layer; The main body portions of the first doped layer and the main body portions of the second doped layer are alternately distributed on one side of the backlight surface of the semiconductor substrate, and the first doped layer and the second doped layer have opposite conductivity types; A portion of the first doped layer and a portion of the second doped layer are electrically connected and form a side mating surface, wherein the side mating surface has a first bending structure.

2. The back contact battery according to claim 1, wherein, The first bending structure includes a plurality of first docking sections that are bent and connected in a direction parallel to the backlight surface.

3. The back contact battery according to claim 2, wherein, At least one of the plurality of the first docking sections has a second bending structure.

4. The back contact battery according to claim 3, wherein, The second bending structure includes a plurality of second docking sections that are bent and connected in a direction parallel to the backlight surface.

5. The back contact battery according to claim 3, wherein, The first portion of the first doped layer and the second portion of the second doped layer are electrically connected and form a first side mating surface; The second portion of the second doped layer is also electrically connected to the semiconductor substrate and forms a second side mating surface; Both the first side mating surface and the second side mating surface have the first bending structure, and the second side mating surface also has the second bending structure.

6. The back contact battery according to claim 4, wherein, Each of the first docking sections has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1; Each of the second docking sections has a second protrusion, and the distance between the maximum points of two adjacent second protrusions is T2; Where T1 > T2.

7. The back contact battery according to claim 6, wherein, T1 is 5-100 times that of T2.

8. The back contact battery according to claim 6, wherein, In a direction perpendicular to the extension direction of the first bending structure, the first bending structure has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1. In a direction perpendicular to the extension direction of the second bending structure, the second bending structure has a second maximum point and a second minimum point, and the distance between the second maximum point and the second minimum point is δ2. Among them, δ1>δ2.

9. The back contact battery according to claim 2, wherein, Each of the first docking sections has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1; In a direction perpendicular to the extension direction of the first bending structure, the first bending structure has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1. Where 0.00005≤T1 / δ1≤500000.

10. The back contact battery according to claim 2, wherein, In a direction parallel to the backlight surface, each of the side mating surfaces has a bending unfolding length L and an end straight line length D, where L > 1.001D.

11. The back contact battery according to claim 2, wherein, Each of the first docking sections has a first protrusion, which has one or more of the following shapes: arc-shaped, square-shaped, trapezoidal, triangular, and irregular.

12. The back contact battery according to claim 1, in, A conductive connection structure is provided between a portion of the first doped layer and a portion of the second doped layer, wherein each of the conductive connection structures includes at least two side mating surfaces.

13. The back contact battery according to claim 12, wherein, 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; 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 extensions of the first doped layer and the extensions of the second doped layer are electrically connected at the spacer region to form the conductive connection structure.

14. The back contact battery according to claim 13, wherein, The extensions of the first doped layer and the extensions of the second doped layer overlap in an alternating manner.

15. The back contact battery according to claim 13, wherein, The extension of the second doped layer covers the extension of the first doped layer to achieve an overlap, and in the extension direction of the interval region, the length of the extension of the second doped layer is greater than the length of the extension of the first doped layer.

16. The back contact battery according to claim 15, wherein, The end of the extension of the second doped layer extends to the junction of the spacer region and the main body of the first doped layer.

17. The back contact battery according to claim 16, wherein, The extension of the second doped layer extends across the interval region and extends such that the end of the extension of the second doped layer is covered by the body of the first doped layer.

18. The back contact battery according to claim 12, wherein, 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; The second doped layer further includes an extension of the second doped layer; The extension of the second doped layer extends across the interval region and extends such that the end of the extension of the second doped layer is covered by the body of the first doped layer.

19. The back contact battery according to claim 12, wherein, The first bending structure includes multiple docking sections that are bent and connected in a direction parallel to the backlight surface.

20. The back contact battery according to claim 19, wherein, Each of the docking sections has a protrusion, and the distance between the maximum points of two adjacent protrusions is T1; In a direction perpendicular to the extension direction of the first bending structure, the first bending structure has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1. Where 0.00005≤T1 / δ1≤500000.

21. The back contact battery according to claim 1, wherein, 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; The first doped layer further includes an extension of the first doped layer, which extends at least across a portion of the spacing region and extends below the second doped layer, and the extension of the first doped layer and the second doped layer are electrically connected.

22. The back contact battery according to claim 21, wherein, The second doped layer further includes an extension of the second doped layer, which extends at least across a portion of the spacer region, and the extensions of the first doped layer and the second doped layer are electrically connected to form a conductive connection structure.

23. The back contact battery according to claim 22, wherein, In the extending direction of the spacer region, the length of the extension of the first doped layer included in at least one of the conductive connection structures is equal to the length of the extension of the second doped layer; and / or, in the extending direction of the spacer region, the length of the extension of the first doped layer included in at least one of the conductive connection structures is greater than the length of the extension of the second doped layer; and / or, in the extending direction of the spacer region, the length of the extension of the first doped layer included in at least one of the conductive connection structures is less than the length of the extension of the second doped layer.

24. The back contact battery according to claim 21, wherein, The extension of the first doped layer extends across the spacing region and extends below the main body of the second doped layer, and the extension of the first doped layer and the main body of the second doped layer are electrically connected.

25. The back contact battery according to claim 24, wherein, The extension of the first doped layer extends below the body portion of the adjacent second doped layer, and its end extends below the body portion of the second doped layer and terminates at a position without exceeding the body portion of the second doped layer.

26. The back contact battery according to claim 25, wherein, A second electrode is disposed above the second doped layer; In the extending direction of the extension of the first doped layer, the distance between the end of the extension of the first doped layer and the upstream side of the projection of the contact portion of the second electrode is W1, where W1 > 0.

27. The back contact battery according to claim 26, wherein, The width of the spacer region in the extension direction of the extension portion of the first doped layer is W2, where W2 > W1.

28. The back contact battery according to claim 21, wherein, The extension of the first doped layer extends below the body portion of the adjacent second doped layer, and its end extends beyond the downstream side of the body portion of the second doped layer.

29. The back contact battery according to claim 24, wherein, An extension of the first doped layer extends below the body portion of an adjacent second doped layer, with its end extending beyond the downstream side of the body portion of the second doped layer, and its end further extending to the upstream side of the body portion of another first doped layer adjacent to the body portion of the second doped layer.

30. The back contact battery according to claim 21, wherein, The main body of the first doped layer includes a strip-shaped portion of the first doped layer, and the main body of the second doped layer includes a strip-shaped portion of the second doped layer; Wherein, the extension of the first doped layer extends from a local region of the strip-shaped portion of the first doped layer toward the strip-shaped portion of the second doped layer, and the extension of the first doped layer extends across the interval region and extends below the strip-shaped portion of the second doped layer, and the extension of the first doped layer and the strip-shaped portion of the second doped layer are electrically connected.

31. The back contact battery according to claim 21, wherein, The main body of the first doped layer includes a strip-shaped portion of the first doped layer and a connecting portion of the first doped layer, wherein the connecting portion of the first doped layer is used to connect multiple strip-shaped portions of the first doped layer; the second doped layer includes a strip-shaped portion of the second doped layer and a connecting portion of the second doped layer, wherein the connecting portion of the second doped layer is used to connect multiple strip-shaped portions of the second doped layer. The back contact battery further includes one or more of the following structures: The extension of the first doped layer extends from a local region of the strip-shaped portion of the first doped layer toward the strip-shaped portion of the second doped layer, and the extension of the first doped layer extends across the interval region and extends below the strip-shaped portion of the second doped layer, and the extension of the first doped layer and the strip-shaped portion of the second doped layer are electrically connected. The extension of the first doped layer extends from a local area of ​​the strip-shaped portion of the first doped layer toward the connection portion of the second doped layer, and the extension of the first doped layer extends across the interval region and extends below the connection portion of the second doped layer, and the extension of the first doped layer and the connection portion of the second doped layer are electrically connected. The extension of the first doped layer extends from all or part of the connecting portion of the first doped layer toward the strip-shaped portion of the second doped layer, and the extension of the first doped layer extends across the spacing region and extends below the strip-shaped portion of the second doped layer, and the extension of the first doped layer and the strip-shaped portion of the second doped layer are electrically connected.

32. The back contact battery according to claim 21, wherein, The extension of the first doped layer and the second doped layer form a stacked structure with at least two side mating surfaces.

33. The back contact battery according to claim 32, wherein, The side mating surface of the stacked structure has the first bending structure; The first bending structure includes multiple docking sections that are bent and connected in a direction parallel to the backlight surface.

34. The back contact battery according to claim 33, wherein, Each of the docking sections has a protrusion, and the distance between the maximum points of two adjacent protrusions is T1; In a direction perpendicular to the extension direction of the first bending structure, the first bending structure has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1. Where 0.00005≤T1 / δ1≤500000.

35. A photovoltaic module, wherein, The photovoltaic module includes: Battery string, the battery string being formed by the electrical connection of a plurality of back-contact batteries as described in any one of claims 1-34; and An encapsulation layer that covers the surface of the battery string.

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