Back contact battery and photovoltaic module

Abstract

The invention provides a back contact battery, which comprises a semiconductor substrate, a first doping layer, a second doping layer and an electrode contact part, and is characterized in that the electrode contact part is arranged on the first doping layer; the main body part of the first doping layer and the main body part of the second doping layer are alternately distributed on the backlight surface of the semiconductor substrate at intervals, the first region of the first doping layer is electrically connected with the first region of the second doping layer, and the conduction types of the first doping layer and the second doping layer are opposite; wherein at least one concave structure is formed on the backlight surface of the semiconductor substrate, and the at least one concave structure is arranged between the electrode contact part and the electrical connection part. The invention also provides a photovoltaic module. According to the back contact battery provided by the invention, the hot spot risk of the back contact battery is further reduced by forming the concave structure.

Description

Technical Field

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

[0002] A back-contact cell refers to a solar cell with no electrodes on the light-facing side of the cell, and both the positive and negative electrodes are arranged on the back-light side of the cell. This can reduce the shading of the cell by the electrodes, increase the short-circuit current of the cell, and improve the energy conversion efficiency of the cell. During the actual use of the back-contact cell, bird droppings, leaves, dust and other obstructions may fall on the back-contact cell. When the cell is blocked, the temperature will rise and produce a hot spot effect. If the temperature generated by the hot spot exceeds a certain temperature value, it will cause problems such as delamination of the photovoltaic module, burning of the back panel, and cracking of the glass, which will cause the entire solar cell to be scrapped. In severe cases, it may cause a fire risk.

[0003] Therefore, there is still a need to provide an improved back contact cell and photovoltaic module to reduce the hot spot problem. Summary of the invention

[0004] In a first aspect of the present invention, a back contact battery is provided, comprising: a semiconductor substrate, a first doping layer, a second doping layer and an electrode contact portion, wherein the electrode contact portion is disposed on the first doping layer;

[0005] The main body of the first doping layer and the main body of the second doping layer are alternately distributed on the backlight surface of the semiconductor substrate, the first region of the first doping layer and the first region of the second doping layer are electrically connected, and the first doping layer and the second doping layer have opposite conductivity types;

[0006] Wherein, at least one recessed structure is formed on the backlight surface of the semiconductor substrate, and the at least one recessed structure is arranged between the electrode contact portion and the electrical connection portion.

[0007] The back contact cell of the present invention forms a leakage channel at the electrical connection between the first doping layer and the second doping layer by electrically connecting the first region of the first doping layer and the first region of the second doping layer, thereby reducing the risk of hot spots in the back contact cell; at the same time, at least one recessed structure is provided between the electrode contact portion on the backlight surface of the semiconductor substrate and the electrical connection, and the recess of the recessed structure helps to bring the distance between other regions of the first doping layer and other regions of the second doping layer closer between the semiconductor substrate, thereby enabling carriers to be transmitted to form another leakage channel. In other words, a new leakage channel is added within a certain distance range of the electrical connection, further reducing the risk of hot spots.

[0008] Optionally, at least one recessed structure enables a carrier transmission distance between the second region of the first doped layer and the second region of the second doped layer in the semiconductor substrate to be less than a preset distance. The recessed structure can form another leakage channel, further reducing the risk of hot spots.

[0009] Optionally, along the direction away from the backlight surface of the semiconductor substrate, the main body of the first doped layer is higher than or flush with the main body of the second doped layer, and at least one recessed structure is arranged below the first doped layer. By arranging the recessed structure below the high-doped layer, the carrier transmission distance between the part of the high-doped layer that is recessed with the recessed structure and the low-doped layer between the semiconductor substrate can be made closer, so that the carriers are transmitted in the newly added leakage channel, further reducing the risk of hot spots.

[0010] Optionally, the first region of the second doped layer is stacked on the first region of the first doped layer, and an insulating layer is disposed between the stacks, which are electrically connected at side butt surfaces of the stacks, and at least one recessed structure is disposed under the stacks.

[0011] Optionally, along a direction away from the backlight surface of the semiconductor substrate, a main body of the first doping layer is higher than a main body of the second doping layer, and at least one recessed structure is disposed below the second doping layer.

[0012] Optionally, along the direction away from the backlight surface of the semiconductor substrate, the main body of the first doped layer is higher than or flush with the main body of the second doped layer, at least one recessed structure is a plurality of recessed structures, the first part of the plurality of recessed structures is located below the first doped layer, and the second part of the plurality of recessed structures is located below the second doped layer.

[0013] Optionally, a distance between at least one recessed structure and the electrical connection point is less than or equal to a distance between the electrode contact portion and the electrical connection point.

[0014] Optionally, a longitudinal section of the at least one recess structure along a thickness direction of the semiconductor substrate has an inverted trapezoidal shape.

[0015] Optionally, at least one of the recessed structures has a depth h of 0.5 μm. <h<5μ m。

[0016] Optionally, at least one recessed structure is a plurality of recessed structures that are partially or completely continuous.

[0017] Optionally, the plurality of partially continuous or fully continuous recessed structures include a plurality of recessed structure groups, wherein each of the plurality of recessed structure groups includes a plurality of fully continuous or partially continuous recessed structures in the same direction.

[0018] Optionally, the recessed structures included in the plurality of recessed structure groups are parallel to each other; or,

[0019] The angles between the recessed structures included in the plurality of recessed structure groups are less than or equal to 50°.

[0020] Optionally, the recess structures included in the first recess structure group among the plurality of recess structure groups are along an extension direction of the main body of the first doping layer or the main body of the second doping layer.

[0021] Optionally, the recess structures included in the first recess structure group among the plurality of recess structure groups are distributed along a direction in which the main body portion of the first doping layer and the main body portion of the second doping layer are alternately spaced.

[0022] Optionally, the length of the partially or fully continuous plurality of recess structures is greater than or equal to the length of the electrical connection along the extension direction of the main body of the first doping layer or the main body of the second doping layer.

[0023] Optionally, depths of the plurality of partially or fully continuous recessed structures are the same or different.

[0024] In a second aspect of the present invention, a photovoltaic module is provided, comprising a cover plate, a back plate, and a back contact cell disposed between the cover plate and the back plate, wherein the back contact cell is the back contact cell described in the first aspect.

[0025] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0027] Figure 1 Schematic diagram of some components of a back contact battery according to an embodiment of the present invention.

[0028] Figure 2 FIG. 4 is a schematic diagram of some components of a back contact battery according to another embodiment of the present invention.

[0029] Figure 3 FIG. 4 is a schematic diagram of some components of a back contact battery according to another embodiment of the present invention.

[0030] Figure 4 FIG. 4 is a schematic diagram of some components of a back contact battery according to another embodiment of the present invention.

[0031] Figure 5 FIG. 4 is a schematic diagram of some components of a back contact battery according to another embodiment of the present invention.

[0032] Figure 6 Schematic diagram of some components of a back contact battery provided with multiple recessed structures.

[0033] Figure 7 It is a schematic diagram of the distribution relationship between the first doping layer and the second doping layer of the back contact battery according to an embodiment of the present invention.

[0034] Figure 8 This is another schematic diagram of the distribution relationship between the first doping layer and the second doping layer of the back contact battery according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the present invention will 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 the present invention. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0036] Various structural schematic diagrams according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0037] In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. In addition, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "under" the other layer / element. In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] The embodiment of the present invention provides a back contact battery 100, which includes: a semiconductor substrate 101, a first doping layer 200, a second doping layer 300 and an electrode contact portion 123, wherein the electrode contact portion 123 is arranged on the first doping layer 200; the main body portion 204 of the first doping layer and the main body portion 304 of the second doping layer are alternately distributed on the backlight surface of the semiconductor substrate 101, and the first doping layer and the second doping layer are electrically connected (such as Figure 1 As shown in the electrical connection 400), the conductivity types of the first doping layer 200 and the second doping layer 300 are opposite; wherein at least one recessed structure 700 is formed on the backlight surface of the semiconductor substrate 101, and at least one recessed structure 700 is arranged between the electrode contact portion 123 and the electrical connection 400.

[0041] It can be understood that the electrical connection between the first doping layer and the second doping layer can be that the end portions of the first region 251 of the first doping layer and the second region 351 of the second doping layer are in contact. Figure 1 As shown, the first region 251 of the first doped layer may be the end of the first doped layer close to the second doped layer, and the first region 351 of the second doped layer may be the end of the second doped layer close to the first doped layer. This application does not limit this.

[0042] The back contact cell 100 of the embodiment of the present invention forms a leakage channel at the electrical connection 400 between the first doping layer 200 and the second doping layer 300 by electrically connecting the first region 251 of the first doping layer and the first region 351 of the second doping layer, thereby reducing the risk of hot spots in the back contact cell 100; at the same time, at least one recessed structure 700 is provided between the electrode contact portion 123 on the backlight surface of the semiconductor substrate 101 and the electrical connection 400, and the recess of the recessed structure 700 helps to bring other regions of the first doping layer 200 and other regions of the second doping layer 300 closer to each other between the semiconductor substrate 101, that is, to limit the range of the recessed structure, thereby enabling carriers to be transmitted to form another leakage channel. In other words, within a certain distance range of the electrical connection 400, a new leakage channel is added, further reducing the risk of hot spots.

[0043] In addition, by providing at least one recessed structure 700 , carriers can be better collected, thereby improving the efficiency of the battery.

[0044] In a possible implementation, the recessed structure 700 may be disposed between the electrical connection portion 400 and the electrode contact portion 123 along a straight line perpendicular to the electrode extension direction, that is, Figure 1 The first direction in the diagram is between the electrical connection 400 and the electrode contact portion 123. The electrode extension direction is a direction perpendicular to the paper surface, and can also be called the collector electrode extension direction, the fine grid line extension direction, or the second direction.

[0045] refer to Figure 1 , the electrode contact portion 123 is disposed on the first doped layer 200. Generally, the first electrode 121 may include a transmission portion (not numbered in the figure) and an electrode contact portion 123, and the transmission portion is in electrical contact with the first doped layer 200 through the electrode contact portion 123. Similarly, the second electrode 122 may include a transmission portion and a contact portion, and the transmission portion is in electrical contact with the second doped layer 300 through the contact portion.

[0046] The embodiment of the present invention further provides a photovoltaic module (not shown in the figure), wherein the photovoltaic module includes a cover plate, a back plate, and a back contact cell 100 disposed between the cover plate and the back plate, and the back contact cell 100 is the aforementioned back contact cell 100. The photovoltaic module has an effect similar to that of the aforementioned back contact cell 100.

[0047] The back contact battery 100 according to the embodiment of the present invention will be described in more detail below with reference to the accompanying drawings.

[0048] The back contact cell 100 refers to a solar cell in which the light-facing side 111 of the cell has no electrode, and the positive electrode and the negative electrode are both arranged on the backlight side 112 of the cell. This can reduce the shading of the electrode to the cell, increase the short-circuit current of the cell, and improve the energy conversion efficiency of the cell.

[0049] It can be understood that, in this article, "first doping layer" and "second doping layer" are only for convenience of description, and the first doping layer 200 and the second doping layer 300 can be interchanged in terms of function and setting position. Alternatively, the back contact battery 100 includes: a semiconductor substrate 101, a first doping layer 200, a second doping layer 300 and an electrode contact portion 123, and the electrode contact portion 123 is arranged on the second doping layer 300; the main body 204 of the first doping layer and the main body 304 of the second doping layer are alternately distributed on the backlight surface of the semiconductor substrate 101, the first region 251 of the first doping layer and the first region 351 of the second doping layer are electrically connected, and the first doping layer 200 and the second doping layer 300 have opposite conductivity types; wherein at least one recessed structure 700 is formed on the backlight surface of the semiconductor substrate 101, and the at least one recessed structure 700 is arranged between the electrode contact portion 123 and the electrical connection. In other words, the recessed structure 700 may be disposed between the electrical connection 400 and the positive electrode contact portion, or may be disposed between the electrical connection 400 and the negative electrode contact portion, which is not limited in the present application.

[0050] For the convenience of description, the back contact cell 100 according to the embodiment of the present invention is described in detail below by way of example, assuming that the electrode contact portion 123 is disposed on the first doping layer 200 .

[0051] In some embodiments, at least one recessed structure 700 enables the transmission distance of carriers between the second region 252 of the first doped layer and the second region 352 of the second doped layer in the semiconductor substrate 101 to be less than a preset distance. The preset distance may be the transmission distance of carriers between the second region 252 of the first doped layer and the second region 352 of the second doped layer in the semiconductor substrate 101 when the recessed structure 700 is not provided; wherein, when the recessed structure 700 is not provided, the transmission path of carriers in the semiconductor substrate 101 may be ideally described as from the second region 252 of the first doped layer ( Figure 1 The second region 252 of the first doped layer when the recessed structure 700 is not provided is shown by a dotted line. Figure 1 point a in the figure, and then transmitted downward to the semiconductor substrate 101 corresponding to the second region 252 of the first doped layer ( Figure 1 b), and then propagates in the semiconductor substrate 101 until it reaches the second region 352 of the second doping layer ( Figure 1 point c). Figure 1The single-point dashed line in FIG. 1 shows a schematic diagram of the transmission path of carriers in the semiconductor substrate 101. In the case of setting the recessed structure 700, it can be seen that the presence of the recessed structure 700 makes the second region 252 of the first doped layer (the right side wall of the recessed structure 700) and the second region 352 of the second doped layer close to each other, and the local area of ​​the semiconductor substrate 101 is placed between the right side wall of the recessed structure 700 and the second region 352 of the second doped layer, so that the carriers can be on the right side wall of the recessed structure 700 ( Figure 1 Specifically, point b) and the second region 352 ( Figure 1 Specifically, the portion of the semiconductor substrate 101 between the points c in the figure is directly transmitted, thereby enabling better leakage. It can be understood that Figure 1 The path between point b and point c in is also the new leakage channel mentioned above.

[0052] Regarding the location of the recessed structure 700, the recessed structure 700 may be located below the first doping layer 200, below the second doping layer 300, or a portion of the recessed structure 700 may be located below the first doping layer 200 and another portion of the recessed structure 700 may be located below the second doping layer 300; when the first doping layer 200 and the second doping layer 300 form a stacked layer 600, the recessed structure 700 may also be located below the stacked layer 600. It is understood that when there are a plurality of recessed structures 700, the recessed structure 700 may be formed at one or more of the aforementioned locations.

[0053] Herein, the recessed structure 700 is disposed under a certain structure, which means that the recessed structure 700 is formed on the backlight surface of the portion of the semiconductor substrate 101 corresponding to the certain structure, and a portion of the certain structure is recessed in the recessed structure 700. For example, the recessed structure 700 is disposed under the first doping layer 200, which means that the recessed structure 700 is formed on the backlight surface of the portion of the semiconductor substrate 101 corresponding to the first doping layer 200, and a portion of the first doping layer 200 is recessed in the recessed structure 700. For another example, the recessed structure 700 is disposed under the second doping layer 300, which means that the recessed structure 700 is formed on the backlight surface of the portion of the semiconductor substrate 101 corresponding to the second doping layer 300, and a portion of the second doping layer 300 is recessed in the recessed structure 700. For another example, the recessed structure 700 is disposed below the stacked layer 600 , which means that the recessed structure 700 is formed on the backlight surface of the semiconductor substrate 101 corresponding to the stacked layer 600 , and a portion of the stacked layer 600 is recessed into the recessed structure 700 .

[0054] In some embodiments, Figure 1As shown, along the direction away from the backlight surface of the semiconductor substrate 101, the main body 204 of the first doped layer is higher than the main body 304 of the second doped layer, and at least one recessed structure 700 is disposed below the first doped layer 200. By disposing the recessed structure 700 below the high-doped layer, the carrier transmission distance between the portion of the high-doped layer recessed by the recessed structure 700 and the low-doped layer in the semiconductor substrate 101 can be made closer, so that the carriers are transmitted in the newly added leakage channel, further reducing the risk of hot spots.

[0055] In some embodiments, Figure 2 As shown, in the direction away from the backlight surface of the semiconductor substrate 101, the main body 204 of the first doped layer is flush with the main body 304 of the second doped layer, and at least one recessed structure 700 is disposed under the first doped layer 200. By disposing the recessed structure 700 under the flush doped layers, the carrier transmission distance between the two doped layers on the semiconductor substrate 101 can be made closer, so that the carriers are transmitted in the newly added leakage channel, further reducing the risk of hot spots.

[0056] In some embodiments, along the direction away from the backlight surface of the semiconductor substrate 101, the main body 204 of the first doped layer is higher than or flush with the main body 304 of the second doped layer, and a portion of at least one recessed structure 700 is disposed below the first doped layer 200, and another portion is disposed below the second doped layer 300. In other words, a portion of the curvature of the curvature of the recessed area of ​​a recessed structure 700 is disposed below the first doped layer 200, and another portion of the curvature is disposed below the second doped layer 300. It can be understood that if the first doped layer 200 and the second doped layer 300 are butted sideways to be electrically connected in the recessed area, the first region 251 of the first doped layer 200 and the second region 252 of the first doped layer 200 may partially overlap.

[0057] The “direction away from the backlight surface of the semiconductor substrate 101” refers to the direction away from the backlight surface in the thickness direction of the semiconductor substrate 101. The thickness direction of the semiconductor substrate 101 can also be described as the direction from the light-facing surface to the backlight surface of the semiconductor substrate 101, or from the backlight surface to the light-facing surface. Figure 1 For example, the thickness direction of the semiconductor substrate 101 is Figure 1 In the up-down direction, the direction away from the backlight surface of the semiconductor substrate 101 is Figure 1 The upward direction in .

[0058] In the phrase “the main body of the first doped layer is higher than or flush with the main body of the second doped layer”, “the main body of the first doped layer is higher than the main body of the second doped layer” means that the main body 204 of the first doped layer is farther away from the backlight surface of the semiconductor substrate 101 than the main body 304 of the second doped layer; “the main body of the first doped layer is flush with the main body of the second doped layer” means that the main body 204 of the first doped layer and the main body 304 of the second doped layer are at the same degree away from the backlight surface of the semiconductor substrate 101. In other words, the backlight surface of the portion of the semiconductor substrate 101 corresponding to the main body 204 of the first doped layer is higher than or flush with the backlight surface of the portion of the semiconductor substrate 101 corresponding to the main body 304 of the second doped layer. The main body 204 of the first doped layer is higher than the main body 304 of the second doped layer means that the backlight surface of the portion of the semiconductor substrate 101 corresponding to the main body 204 of the first doped layer is higher than the backlight surface of the portion of the semiconductor substrate 101 corresponding to the main body 304 of the second doped layer, such as Figure 1 The main body 204 of the first doped layer is flush with the main body 304 of the second doped layer. The backlight surface of the semiconductor substrate 101 corresponding to the main body 204 of the first doped layer is flush with the backlight surface of the semiconductor substrate 101 corresponding to the main body 304 of the second doped layer. Figure 2 shown.

[0059] The first doping layer 200 and the second doping layer 300 are distinguished by whether a stacked layer 600 is formed between the first doping layer 200 and the second doping layer 300 or not. "Stacked layer" means that a part of the first doping layer 200 and a part of the second doping layer 300 are electrically connected in an overlapping manner, for example, the first region 251 of the first doping layer 200 and the first region 351 of the second doping layer 300 are electrically connected in an overlapping manner, such as Figure 2 As shown; “not forming a stack” means that a portion of the first doping layer 200 and a portion of the second doping layer 300 are electrically connected in a butt-jointed manner, for example, the first region 251 of the first doping layer 200 and the first region 351 of the second doping layer 300 are electrically connected in a butt-jointed manner, such as Figure 1 It can be understood that when the stack 600 is formed and the first doping layer 200 is located at the bottom of the stack 600, at least one recessed structure 700 is disposed below the first doping layer 200, which actually includes three situations: the first is that at least one recessed structure 700 is disposed below the portion of the first doping layer 200 where the stack 600 is not formed, such as Figure 3 As shown at the mark 701 in the middle; the second is that at least one recessed structure 700 is disposed below the portion of the first doping layer 200 that forms the stack 600. This situation is referred to herein as the recessed structure 700 being disposed below the stack 600. Figure 3 As shown at mark 702; the third is a combination of the above two, such as Figure 3shown.

[0060] like Figure 3 As shown, in some embodiments, a portion of the second doping layer 300 is stacked on a portion of the first doping layer 200, and an insulating layer 150 is disposed between the stacks 600, and the stacks 600 are electrically connected at the side interface 400, and at least one recessed structure 700 is disposed under the stack 600. By disposing the recessed structure 700 under the stack 600, the distance between the second region 252 of the first doping layer 200 and the second region 352 of the second doping layer 300 is made close to the semiconductor substrate 101, which can further facilitate the transmission of carriers.

[0061] Figure 2 and Figure 3 600 are shown in FIG. Figure 2 Only one recessed structure 700 is shown, and the recessed structure 700 is disposed below a portion of the first doping layer 200 where the stacked layer 600 is not formed; Figure 3 Two recessed structures 700 are shown, wherein at mark 701 , the recessed structure 700 on the left is disposed below the portion of the first doping layer 200 where the stack 600 is not formed, and at mark 702 , the recessed structure 700 on the right is disposed below the stack 600 .

[0062] In one example, reference Figure 3 , along the direction away from the backlight surface of the semiconductor substrate 101, the main body 204 of the first doping layer is higher than the main body 304 of the second doping layer, and a part of the second doping layer 300 is stacked on a part of the first doping layer 200, and an insulating layer 150 is arranged between the stacked layers 600, and they are electrically connected at the side interface 400 of the stacked layers 600, and at least one recessed structure 700 is arranged below the stacked layers 600. Further, the first part of the first doping layer 200 and the second part of the second doping layer 300 are electrically connected, and a first side interface 401 is formed; the second part of the second doping layer 300 (i.e., the second region 402 of the second doping layer) can also realize carrier transmission with the part of the semiconductor substrate 101 with a height difference below the stacked layers 600.

[0063] like Figure 1 As shown, in other embodiments, along the direction away from the backlight surface of the semiconductor substrate 101, the main body 204 of the first doping layer is higher than or flush with the main body 304 of the second doping layer, and a portion of the first doping layer 200 and a portion of the second doping layer 300 are butt-jointed to form a side butt joint 400, and at least one recessed structure 700 is disposed under the first doping layer 200.

[0064] In some other embodiments, along a direction away from the backlight surface of the semiconductor substrate 101 , the main body 204 of the first doping layer is higher than the main body 304 of the second doping layer, and at least one recessed structure 700 is disposed below the second doping layer 300 .

[0065] refer to Figure 4 In the case of forming a stack 600, that is, the first region 251 of the first doping layer 200 and the first region 351 of the second doping layer 300 are overlapped to form an electrical connection, the second doping layer 300 may include a main body 304 of the second doping layer and an extension 303 of the second doping layer, and there is a spacing region 190 between the main body 204 of the first doping layer and the main body 304 of the second doping layer, wherein the extension 303 of the second doping layer extends across the spacing region 190 and is stacked on the first region 251 of the first doping layer 200, and an insulating layer 150 is disposed between the stack 600, and is electrically connected at the side interface 400 of the stack 600. In this case, the recessed structure 700 can be disposed below the portion of the second doping layer 300 that does not form the stack 600 and is located in the spacing region 190, and can also be disposed below the portion of the second doping layer 300 that does not form the stack 600 and is not located in the spacing region 190, that is, below the main body 304 of the second doping layer. Figure 4 In the figure, the recessed structure marked 703 is arranged below the portion of the second doping layer 300 located in the spacing region 190, that is, below the portion of the extension portion 303 of the second doping layer located in the spacing region 190; the recessed structure marked 704 is arranged below the main body 304 of the second doping layer.

[0066] In some other embodiments, along the direction away from the backlight surface of the semiconductor substrate 101, the main body 204 of the first doped layer is higher than or flush with the main body 304 of the second doped layer, the at least one recessed structure 700 is a plurality of recessed structures 700, the first portion of the plurality of recessed structures 700 is located below the first doped layer 200, and the second portion of the plurality of recessed structures 700 is located below the second doped layer 300. Figure 4 and Figure 5 The recessed structure marked 701 is disposed below the first doping layer 200 ; the recessed structure marked 703 and the recessed structure marked 704 are disposed below the second doping layer 300 .

[0067] In some embodiments, the distance between at least one recessed structure 700 and the electrical connection is less than or equal to the distance between the electrode contact portion 123 and the electrical connection. With the electrical connection as the center, in a direction parallel to the backlight surface, the recessed structure 700 may be arranged around the electrical connection, and the distance between the recessed structure 700 and the electrical connection is less than or equal to the distance between the electrode contact portion 123 and the electrical connection.

[0068] It is understood that the distance between the electrode contact portion 123 and the electrical connection is usually not greater than 500 microns, such as 500 microns, 400 microns, 300 microns, 200 microns, and 100 microns. The distance between the recessed structure 700 and the electrical connection can be, for example, 500 microns, 400 microns, 300 microns, 200 microns, and 100 microns.

[0069] When the stack 600 is formed and the insulating layer 150 is disposed between the stacks 600, and when the stack 600 is not formed, the electrical connection is the side interface 400. At this time, the distance between the electrode contact portion 123 and the electrical connection is the distance between the electrode contact portion 123 and the side interface 400 projected on the semiconductor substrate 101. In the direction parallel to the backlight surface, with the position of the side interface 400 as the center, the recessed structure 700 can be arranged around the side interface 400, and the distance between the recessed structure 700 and the side interface 400 is less than or equal to the distance between the electrode contact portion 123 and the electrical connection. The distance between the recessed structure 700 and the side interface 400 is usually the distance between the bottom midpoint of the recessed structure 700 and the projection of the side interface 400 on the semiconductor substrate 101, such as Figure 2 As shown in D.

[0070] In the case where the stack 600 is formed but the insulating layer 150 is not disposed between the stacks 600, the electrical connection includes the side interface 400 and the top interface in the stack 600. At this time, the distance between the recessed structure 700 and the electrical connection can be the distance between the electrode contact portion 123 and the side interface 400 and / or the top interface. For example, in the direction parallel to the backlight surface, with the position of the side interface 400 as the center, the recessed structure 700 can be arranged around the side interface 400, and the distance between the recessed structure 700 and the side interface 400 is less than or equal to the distance between the electrode contact portion 123 and the electrical connection. For another example, in the direction parallel to the backlight surface, with the position of the center point of the top interface as the center, the recessed structure 700 can be arranged around the top interface, and the distance between the recessed structure 700 and the top interface is less than or equal to the distance between the electrode contact portion 123 and the electrical connection. The distance between the recess structure 700 and the top-surface junction surface is generally the distance between the projections of the bottom midpoint of the recess structure 700 and the center point of the top-surface junction surface on the semiconductor substrate 101 .

[0071] In some embodiments, Figure 6As shown, the length of the electrical connection along the extension direction of the main body 204 of the first doping layer is L. Optionally, L∈(20μm-2000μm). The length of the electrical connection along the extension direction of the main body 204 of the first doping layer or the main body 304 of the second doping layer can also be considered as the length of the side docking surface 400 in its extension direction. L can be, for example, 20μm, 100μm, 500μm, 1000μm, 2000μm. By limiting L∈(20μm-2000μm), it is possible to avoid the problem that the side docking surface 400 is too small, resulting in too little improvement in the anti-hot spot effect due to the setting of the side docking surface 400. It is also possible to avoid the problem that the side docking surface 400 is too large, resulting in a large loss in battery conversion efficiency due to PN zone contact. "The extension direction of the main body of the first doping layer or the main body of the second doping layer" specifically refers to the extension direction of the strip-shaped portion of the first doping layer or the strip-shaped portion of the second doping layer, which will be referred to below. Figure 7 and Figure 8 Describe in detail.

[0072] It is understandable that the extension direction of the main body 204 of the first doping layer is the same as the extension direction of the main body 304 of the second doping layer. The extension direction of the main body 204 of the first doping layer and the extension direction of the main body 304 of the second doping layer are perpendicular to the first direction.

[0073] In some embodiments, Figure 1 As shown, the longitudinal section of at least one recessed structure 700 along the thickness direction of the semiconductor substrate 101 has an inverted trapezoidal shape. The longitudinal section of the recessed structure 700 may be a standard inverted trapezoidal shape or may be approximately inverted trapezoidal shape. By setting the longitudinal section of the recessed structure 700 to have an inverted trapezoidal shape, on the one hand, it is convenient for processing, and on the other hand, the inverted trapezoidal shape enables the right side slope of the recessed structure 700 to better realize the transmission of carriers in the semiconductor substrate 101.

[0074] It is understandable that the longitudinal cross-section in the thickness direction may also be a rectangle, a regular trapezoid, or other shapes, and the present application does not limit this.

[0075] It is understandable that the cross section of at least one recess structure 700 along the direction parallel to the backlight surface of the semiconductor substrate 101 may have at least one of the following shapes: rhombus, square, trapezoid, approximately rhombus, approximately square, approximately trapezoid.

[0076] In some embodiments, Figure 5As shown, the depth of the recessed structure 700 is h. Optionally, 0.5μm < h < 5μm. The depth h of the recessed structure 700 is the distance between the bottom of the recessed structure 700 and the top of the adjacent semiconductor substrate 101 in the thickness direction of the semiconductor substrate 101. When the heights of the tops of the two semiconductor substrates 101 adjacent to the recessed structure 700 are different, two depths can be calculated and then averaged. The depth h of the recessed structure 700 can be, for example, 0.6μm, 1μm, 2μm, 4μm, 4.9μm. By defining 0.5μm < h < 5μm, it is possible to avoid the problem that the setting of the recessed structure 700 has too little improvement on the carrier transport effect due to the overly shallow recess degree, and it is also possible to avoid the problem that the recessed structure 700 is too large and affects the processing efficiency. When a plurality of recessed structures 700 are formed on the backlight surface of the semiconductor substrate 101, the depths of the plurality of recessed structures 700 can be the same or different.

[0077] Next, the relative relationship between the plurality of recessed structures 700 in the back contact battery 100 when there are a plurality of recessed structures 700 will be described.

[0078] In some embodiments, at least one recessed structure 700 is a plurality of recessed structures 700 that are partially continuous or completely continuous. The plurality of completely continuous recessed structures 700 means that among the plurality of recessed structures 700, there are overlapping parts between adjacent recessed structures 700, such as Figure 6 the recessed structures at the marked 701, 702, 731, 704. The plurality of partially continuous recessed structures 700 means that among the plurality of recessed structures 700, there are not overlapping parts between adjacent recessed structures 700.

[0079] It can be understood that the overlapping part between the recessed structures 700 can be that a vertex or an edge of the recessed structure 700 overlaps, or a region overlaps. The present application does not limit this.

[0080] The length of the plurality of recessed structures 700 that are partially continuous or completely continuous can be greater than or equal to the length of the electrical connection portion along the extension direction of the main body 204 of the first doping layer or the main body 304 of the second doping layer. Figure 6 In, the lengths of the plurality of recessed structures at the marked 701, 702, 704 are greater than or equal to the length L of the electrical connection portion along the extension direction of the main body 204 of the first doping layer or the main body 304 of the second doping layer.

[0081] It should be noted that in the case of the semiconductor substrate 101 where the plurality of recessed structures 700 are in the spacer region 190, in order to avoid affecting the spacer region texturing, the length of the plurality of recessed structures 700 is less than or equal to the length L of the electrical connection portion along the extension direction of the main body 204 of the first doping layer, such as Figure 6The multiple recessed structures at the mark 703 (including marks 731, 732, 733, 734) are Figure 6 The extension portion 303 of the second doping layer extends across the spacing region 190 and overlaps the main body 204 of the first doping layer to form a stack 600. The multiple recessed structures 700 in the spacing region 190 are actually arranged under the portion of the extension portion 303 of the second doping layer in the spacing region 190. Therefore, the length of the multiple recessed structures 700 is less than or equal to the length of the extension portion 303 of the second doping layer along the extension direction of the main body 204 of the first doping layer.

[0082] The depths of the partially or fully continuous plurality of recess structures 700 may be the same or different. For example, the depth h of some recess structures 700 may be 0.6 μm, and the depth h of other recess structures 700 may be 4.9 μm.

[0083] In some embodiments, the partially or completely continuous plurality of recessed structures 700 may include a plurality of recessed structure groups, wherein each of the plurality of recessed structure groups includes a plurality of recessed structures 700 that are completely or partially continuous in the same direction. Figure 6 In the figure, the multiple recessed structures marked 701, 702, 731, 732, 733, 734, and 704 are respectively a recessed structure group, and each recessed structure group may include multiple recessed structures 700 that are completely continuous or partially continuous in the same direction.

[0084] In some possible implementations, a plurality of recessed structure groups may be disposed under the first doping layer 200 and under the second doping layer 300 at the same time.

[0085] In some other possible implementations, the plurality of recessed structure groups may be partially disposed under the first doping layer 200 , and another portion disposed under the second doping layer 300 .

[0086] The recessed structures 700 included in the plurality of recessed structure groups are parallel to each other; or, the angles between the recessed structures 700 included in the plurality of recessed structure groups are less than or equal to 50°. Figure 6 In the embodiment, the recessed structures included in the recessed structure groups marked 701, 702, 731, 732, 733, and 704 are parallel to each other, and the recessed structure included in the recessed structure group marked 734 has an angle less than 50° with other recessed structures. The angles between the recessed structures included in the plurality of recessed structure groups are less than or equal to 50°, for example, 50°, 40°, 30°, 20°, or 10°.

[0087] In some embodiments, the first recessed structure group among the plurality of recessed structure groups includes a recessed structure 700 along the extension direction of the main body 204 of the first doped layer. When the recessed structure 700 is along the extension direction of the main body 204 of the first doped layer, the anti-hot spot effect is better improved.

[0088] It can be understood that the recessed structures included in other recessed structure groups among the plurality of recessed structure groups may have the same direction as the recessed structures included in the first recessed structure group, that is, the recessed structures in other recessed structure groups also have the same extension direction as the main body 204 of the first doping layer. Alternatively, the recessed structures in other recessed structure groups among the plurality of recessed structure groups may have a different direction from the recessed structures included in the first recessed structure group, which is not limited in the present application.

[0089] In some other embodiments, the recessed structures 700 included in the first recessed structure group among the plurality of recessed structure groups are arranged in a direction along which the main body portion 204 of the first doping layer and the main body portion 304 of the second doping layer are alternately spaced. “The direction in which the main body portion of the first doping layer and the main body portion of the second doping layer are alternately spaced” specifically refers to the direction in which the strip-shaped portion of the first doping layer or the strip-shaped portion of the second doping layer is alternately spaced, see Figure 7 and Figure 8 .

[0090] It can be understood that the recessed structures included in other recessed structure groups in the plurality of recessed structure groups may have the same direction as the recessed structures included in the first recessed structure group, that is, the recessed structures in other recessed structure groups are also in the same direction as the main body portion 204 of the first doping layer and the main body portion 304 of the second doping layer are alternately distributed. Alternatively, the recessed structures in other recessed structure groups in the plurality of recessed structure groups may have a different direction from the recessed structures included in the first recessed structure group, which is not limited in the present application.

[0091] The extension direction of the main body 204 of the first doping layer or the main body 304 of the second doping layer intersects with the direction in which the main body 204 of the first doping layer and the main body 304 of the second doping layer are alternately distributed, and the two are usually perpendicular. "The direction in which the main body 204 of the first doping layer and the main body 304 of the second doping layer are alternately distributed" is the same as the first direction.

[0092] The distribution relationship between the first doping layer 200 and the second doping layer 300 of the back contact cell 100 can be two kinds, respectively: Figure 7 and Figure 8 shown.

[0093] Combine the following Figure 7 A back contact cell 100 according to an embodiment of the present application is described.

[0094] exist Figure 7In the embodiment, the first doping layer 200 includes a main body 204 of the first doping layer, and the second doping layer 300 includes a main body 304 of the second doping layer. The main body 204 of the first doping layer and the main body 304 of the second doping layer are alternately distributed in strips. There is a spacing region 190 between the main body 204 of the first doping layer and the main body 304 of the second doping layer. Specifically, Figure 7 , the main body 204 of the first doping layer includes the strip-shaped portion 201 of the first doping layer. The main body 304 of the second doping layer includes the strip-shaped portion 301 of the second doping layer. The spacing region 190 is formed between the strip-shaped portion 201 of the first doping layer and the strip-shaped portion 301 of the second doping layer. Here, the region where the strip-shaped portion 201 of the first doping layer is located is the first doping region 191, the region where the strip-shaped portion 301 of the second doping layer is located is the second doping region 192, and the spacing region 190 is formed between the first doping region 191 and the second doping region 192.

[0095] In a possible implementation, the first doping layer 200 may further include an extension portion 203 of the first doping layer, the extension portion 203 of the first doping layer extending from a local area of ​​the main body 204 of the first doping layer toward the second doping layer 300, that is, extending from a local area of ​​the strip portion 201 of the first doping layer toward the strip portion 301 of the second doping layer 300. In other words, the first doping layer extends toward the second doping layer, and an electrical connection is achieved at the second doping layer. Accordingly, the recessed structure 700 is disposed below the first doping layer, which can be understood as the recessed structure 700 being disposed below the main body of the first doping layer and / or below the extension portion of the first doping layer (that is, the spacing area).

[0096] In another possible implementation, the second doping layer 300 may further include an extension portion 303 of the second doping layer, and the extension portion 303 of the second doping layer extends from a local area of ​​the main body 304 of the second doping layer toward the first doping layer 200, that is, extends from a local area of ​​the strip portion 301 of the second doping layer toward the strip portion 201 of the first doping layer. In other words, the second doping layer extends toward the first doping layer to achieve electrical connection, and achieves electrical connection at the first doping layer. Accordingly, the recessed structure 700 is disposed under the second doping layer, which can be understood as the recessed structure 700 being disposed under the main body of the second doping layer and / or under the extension portion of the second doping layer (i.e., the spacing area).

[0097] In yet another possible implementation, the first doped layer and the second doped layer extend toward each other respectively and are electrically connected at the spacing region 190 .

[0098] It is understandable that the electrical connection between the first doped layer and the second doped layer can be a side contact or a top-bottom stacking contact. The side contact can also be a full side contact or a partial side contact, for example, an isolation layer is provided between the sides and only the holes are directly in contact. The stacking contact can also be a full stacking surface contact or a partial stacking surface contact, for example, an isolation layer is provided at the stacking and only the top-bottom of the holes are in contact. Alternatively, the stacking contact can be an insulating layer provided in the middle and the stacking side contact, as described above. Figure 2 shown.

[0099] It should be noted that the extension portion 203 of the first doping layer is usually formed integrally with the main body portion 204 of the first doping layer, that is, it is extended from a local area of ​​the main body portion 204 of the first doping layer toward the second doping layer 300. However, the extension portion 203 of the first doping layer can also be formed separately from the main body portion 204 of the first doping layer, that is, using an additional process, it is independent of the main body portion 204 of the first doping layer to form a conductive block, wherein the conductive block is structurally connected to the main body portion 204 of the first doping layer and can be the same in material. The extension portion 303 of the second doping layer is similar to the extension portion 203 of the first doping layer, and will not be described in detail here.

[0100] In this way, when forming the stack 600, a portion of the second doping layer 300 is stacked on a portion of the first doping layer 200, and the "portion of the second doping layer" can be a portion of the main body 304 of the second doping layer, or the whole or a portion of the extension 303 of the second doping layer, and the "portion of the first doping layer" can be a portion of the main body 204 of the first doping layer, or the whole or a portion of the extension 203 of the first doping layer. The aforementioned "extension direction of the main body of the first doping layer or the main body of the second doping layer" is the extension direction of the strip portion 201 of the first doping layer or the strip portion 301 of the second doping layer. The aforementioned "direction in which the main body of the first doping layer and the main body of the second doping layer are alternately distributed" is the direction in which the strip portions 201 of the first doping layer or the strip portions 301 of the second doping layer are alternately distributed.

[0101] Regarding the positions of the first doping layer 200 and the second doping layer 300 relative to the semiconductor substrate 101, the first doping layer 200 and the second doping layer 300 may both be formed within the semiconductor substrate 101. Alternatively, the first doping layer 200 and the second doping layer 300 may both be formed on the semiconductor substrate 101. Alternatively, the first doping layer 200 is formed within the semiconductor substrate 101, and the second doping layer 300 is formed on the semiconductor substrate 101.

[0102] Regarding the specific structure of the spacing region 190 , the spacing region 190 may be a blank spacing region disconnected between the main body 204 of the first doping layer and the main body 304 of the second doping layer.

[0103] by Figure 1 and Figure 4 As an example, the formation position and formation method of the electrical connection, that is, the side interface 400 are described. The side interface 400 can be formed at any position of the spacing region 190, the first doping region 191, the second doping region 192, the junction of the spacing region 190 and the first doping region 191, and the junction of the spacing region 190 and the second doping region 192. Specifically, when the side docking surface 400 is formed in the spacing region 190, the side docking surface 400 is electrically connected between all or part of the extension portion 203 of the first doping layer and all or part of the extension portion 303 of the second doping layer; when the side docking surface 400 is formed in the first doping region 191, or at the junction of the spacing region 190 and the first doping region 191, the side docking surface 400 is electrically connected between a part of the strip portion 201 of the first doping layer and all or part of the extension portion 303 of the second doping layer; when the side docking surface 400 is formed in the second doping region 192, or at the junction of the spacing region 190 and the second doping region 192, the side docking surface 400 is electrically connected between a part of the strip portion 301 of the second doping layer and all or part of the extension portion 203 of the first doping layer. The side butt joint surface 400 may be formed by butting a portion of the first doping layer 200 and a portion of the second doping layer 300, or by overlapping a portion of the first doping layer 200 and a portion of the second doping layer 300, for example, a portion of the second doping layer 300 is overlapped on a portion of the first doping layer 200. Figure 1 , a portion of the second doping layer 300 overlaps a portion of the first doping layer 200 to form a side interface 400. Figure 4 , a portion of the first doping layer 200 and a portion of the second doping layer 300 are butted against each other to form a side butt interface 400. As for the contact mode between a portion of the first doping layer 200 and a portion of the second doping layer 300, a portion of the first doping layer 200 and a portion of the second doping layer 300 can be directly in contact with each other to form a side butt interface 400; a portion of the first doping layer 200 and a portion of the second doping layer 300 can also be indirectly in contact with each other to form a side butt interface 400, that is, other layer structures may be provided between a portion of the first doping layer 200 and a portion of the second doping layer 300 as needed, and it is sufficient that a portion of the first doping layer 200 and a portion of the second doping layer 300 can be electrically butted against each other. For example, Figure 7In the figure, at mark 801, the side butt joint 400 is formed by butting between the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer at the spacing region 190; at mark 802, the side butt joint 400 is formed by overlapping between a part of the strip portion 201 of the first doping layer and the extension portion 303 of the second doping layer at the first doping region 191; at mark 803, the side butt joint 400 is formed by overlapping between the extension portion 203 of the first doping layer and the extension portion 301 of the second doping layer at the second doping region 192.

[0104] Regarding the location of the recessed structure 700, depending on the location of the side butt surface 400, the recessed structure 700 can be formed on the semiconductor substrate 101 corresponding to one or more of the following locations: the spacing region 190, the first doping region 191, and the second doping region 192. As mentioned above, when there are multiple recessed structures 700, the multiple recessed structures 700 can be all disposed in the same region on the backlight surface of the semiconductor substrate 101, or can be respectively disposed in different regions on the backlight surface of the semiconductor substrate 101, or can be partially disposed in the same region and the other partially disposed in different regions. Similarly, one or more recessed structures 700 can be formed in the same region on the backlight surface of the semiconductor substrate 101.

[0105] Combine the following Figure 8 A back contact cell 100 according to an embodiment of the present application is described.

[0106] exist Figure 8 In the embodiment, the first doping layer 200 includes a main body 204 of the first doping layer, and the second doping layer 300 includes a main body 304 of the second doping layer. The main body 204 of the first doping layer and the main body 304 of the second doping layer are alternately distributed in a forked shape. There is a spacing region 190 between the main body 204 of the first doping layer and the main body 304 of the second doping layer.

[0107] Specifically, Figure 8In the embodiment, the main body 204 of the first doping layer includes a strip portion 201 of the first doping layer and a connecting portion 202 of the first doping layer, wherein the connecting portion 202 of the first doping layer is used to connect multiple strip portions 201 of the first doping layer. The second doping layer 300 includes a strip portion 301 of the second doping layer and a connecting portion 302 of the second doping layer, wherein the connecting portion 302 of the second doping layer is used to connect multiple strip portions 301 of the second doping layer. The region where the strip portion 201 of the first doping layer is located is the first doping region 191, the region where the strip portion 301 of the second doping layer is located is the second doping region 192, the region where the connecting portion 202 of the first doping layer is located is the third doping region 193, and the region where the connecting portion 302 of the second doping layer is located is the fourth doping region 194. In this case, the spacing region 190 can be: formed between the strip portion 201 of the first doping layer and the strip portion 301 of the adjacent second doping layer, that is, between the first doping region 191 and the second doping region 192; formed between the strip portion 201 of the first doping layer and the connecting portion 302 of the adjacent second doping layer, that is, between the first doping region 191 and the fourth doping region 194; formed between the connecting portion 202 of the first doping layer and the strip portion 301 of the adjacent second doping layer, that is, between the third doping region 193 and the second doping region 192.

[0108] The first doping layer 200 may further include an extension portion 203 of the first doping layer, the extension portion 203 of the first doping layer extending from a local area of ​​the main body portion 204 of the first doping layer toward the second doping layer 300, that is, extending from the strip portion 201 of the first doping layer, or the connecting portion 202 of the first doping layer toward the second doping layer 300. Specifically, the extension portion 203 of the first doping layer extends from a local area of ​​the strip portion 201 of the first doping layer toward the strip portion 301 of the second doping layer or the connecting portion 302 of the second doping layer, or extends from the entire or local area of ​​the connecting portion 202 of the first doping layer toward the strip portion 301 of the second doping layer.

[0109] The second doping layer 300 may further include an extension portion 303 of the second doping layer, and the extension portion 303 of the second doping layer extends from a local area of ​​the main body portion 304 of the second doping layer toward the first doping layer 200, that is, extends from the strip portion 301 of the second doping layer, or the connecting portion 302 of the second doping layer toward the first doping layer 200. Specifically, the extension portion 303 of the second doping layer extends from a local area of ​​the strip portion 301 of the second doping layer toward the strip portion 201 of the first doping layer or the connecting portion 202 of the first doping layer, or extends from the entire or local area of ​​the connecting portion 302 of the second doping layer toward the strip portion 201 of the first doping layer.

[0110] and Figure 7 similar, Figure 8 The extension portion 203 of the first doping layer is usually formed integrally with the main body portion 204 of the first doping layer, but the extension portion 203 of the first doping layer can also be formed separately from the main body portion 204 of the first doping layer. The extension portion 303 of the second doping layer is similar to the extension portion 203 of the first doping layer, and will not be described in detail here.

[0111] Thus, when forming the stack 600, a portion of the second doping layer 300 is stacked on a portion of the first doping layer 200, and "a portion of the second doping layer" may be a portion of the strip portion 301 of the second doping layer, or may be all or part of the connecting portion 302 of the second doping layer, or may be all or part of the extending portion 303 of the second doping layer; "a portion of the first doping layer" may be a portion of the strip portion 201 of the first doping layer, or may be all or part of the connecting portion 202 of the first doping layer, or may be all or part of the extending portion 203 of the first doping layer. It should be understood that a portion of the first doping layer 200 and a portion of the second doping layer 300 in adjacent positions are usually electrically connected to form a side butt interface 400. The aforementioned "extension direction of the main body of the first doping layer or the main body of the second doping layer" is the extension direction of the strip portion 201 of the first doping layer or the strip portion 301 of the second doping layer. The aforementioned “direction in which the main body of the first doping layer and the main body of the second doping layer are distributed alternately at intervals” refers to the direction in which the strip portions 201 of the first doping layer or the strip portions 301 of the second doping layer are distributed alternately at intervals.

[0112] As for the formation position of the electrical connection, similar to the above, it can be the spacing region 190, the first doping region 191, the second doping region 192, the third doping region 193, the fourth doping region 194, the junction between the spacing region 190 and the first doping region 191, the junction between the spacing region 190 and the second doping region 192, the junction between the spacing region 190 and the third doping region 193, the junction between the spacing region 190 and the fourth doping region 194, etc.

[0113] The positions of the first doping layer 200 and the second doping layer 300 relative to the semiconductor substrate 101, the specific structure of the spacing region 190, the formation method of the side docking surface 400, and the contact method between a portion of the first doping layer 200 and a portion of the second doping layer 300 are similar to the above and will not be repeated here.

[0114] For example, Figure 8In the figure, at mark 901, the side butt interface 400 may be formed between an extension portion 203 of the first doping layer (the extension portion 203 of the first doping layer is specifically formed by extending from the connecting portion 202 of the first doping layer toward the strip portion 301 of the second doping layer) and a portion of the end of the strip portion 301 of the second doping layer; at mark 902, the side butt interface 400 may be formed between a portion of the strip portion 201 of the first doping layer and an extension portion 303 of the second doping layer (the extension portion 303 of the second doping layer is specifically formed by extending from the strip portion 301 of the second doping layer toward the strip portion 201 of the first doping layer); at mark 903, the side butt interface 400 may be formed between a portion of the end of the strip portion 201 of the first doping layer and an extension portion 303 of the second doping layer (the extension portion 303 of the second doping layer is specifically formed by extending from the connecting portion 302 of the second doping layer toward the strip portion 201 of the first doping layer).

[0115] Regarding the setting position of the recessed structure 700, similar to the above, depending on the different formation positions of the side docking surfaces, the recessed structure 700 can be formed in the area of ​​the semiconductor substrate 101 corresponding to one or more of the following positions: in the spacing region 190, the first doping region 191, the second doping region 192, the third doping region 193, the fourth doping region 194, the junction between the spacing region 190 and the first doping region 191, the junction between the spacing region 190 and the second doping region 192, the junction between the spacing region 190 and the third doping region 193, and the junction between the spacing region 190 and the fourth doping region 194.

[0116] Combine the following Figure 1 , the overall structure of the back contact battery 100 of an embodiment of the present application is described.

[0117] like Figure 1 As shown, the back contact battery 100 includes: a semiconductor substrate 101, a first doping layer 200, a second doping layer 300 and an electrode contact portion 123, wherein the electrode contact portion 123 is arranged on the first doping layer 200; the main portion 204 of the first doping layer and the main portion 304 of the second doping layer are alternately distributed on the backlight surface of the semiconductor substrate 101, the first region 251 of the first doping layer and the first region 351 of the second doping layer are electrically connected, and the first doping layer 200 and the second doping layer 300 have opposite conductivity types; wherein at least one recessed structure 700 is formed on the backlight surface of the semiconductor substrate 101, and at least one recessed structure 700 is arranged between the electrode contact portion 123 and the electrical connection. The first region 351 of the second doping layer 300 is stacked on the first region 251 of the first doping layer 200, and an insulating layer 150 is arranged between the stacked layers 600, and the stacked layers 600 are electrically connected at the side butt surface 400. Figure 1In the embodiment, the recessed structure 700 is formed between the electrode contact portion 123 and the electrical connection portion and below the first doped layer 200 .

[0118] Figure 1 The back contact cell 100 shown may also include a first dielectric layer 131 between the first doping layer 200 and the semiconductor substrate 101, a second dielectric layer 132 between the second doping layer 300 and the semiconductor substrate 101, a surface passivation layer 140 above the first doping layer 200 and the second doping layer 300, a first electrode 121, and a second electrode 122, wherein the first electrode 121 has an electrode contact portion 123. Electrode contacts (not numbered in the figure) are also provided below the second electrode 122 and above the second doping layer 300.

[0119] It should be noted that, in terms of the specific electrode structure of the positive electrode and the negative electrode, the back contact battery 100 of the embodiment of the present invention may be a "back contact battery without a main grid". In this case, the electrode structure in the back contact battery only includes a plurality of collector electrodes (a first electrode 121 and a second electrode 122). The collector electrodes may also be referred to as fine grid lines. The plurality of collector electrodes may extend along the second direction and be spaced apart along the first direction. Alternatively, the back contact battery 100 of the embodiment of the present invention may also be a "back contact battery with a main grid. In this case, the back contact battery includes a plurality of collector electrodes and a plurality of bus structures (not shown in the figure). The bus structures may also be referred to as bus electrodes. The bus structures are spaced apart along the second direction and extend along the first direction, and are electrically coupled to collector electrodes of the same conductivity type as themselves. The bus structure may be a structure extending over the entire cell or a structure extending over only part of the cell.

[0120] The materials of the various layers and electrodes of the back contact battery 100 of the embodiment of the present invention can refer to any material in the prior art that can be used to prepare the back contact battery 100. The materials of each layer are briefly described below.

[0121] The semiconductor substrate may be a silicon substrate. The silicon substrate may be N-type or P-type silicon with a thickness of 30-500 microns. The backlight surface and the light-facing surface of the semiconductor substrate may be flat. Alternatively, the light-facing surface of the semiconductor substrate may also be a velvet surface.

[0122] The conductivity type of the first doped layer can be N-type, in which case the conductivity type of the second doped layer is P-type; or, the conductivity type of the first doped layer can also be P-type, in which case the conductivity type of the second doped layer is N-type. For the specific materials of the first doped layer and the second doped layer, the N-type doped layer can be one or more of single crystal silicon, polycrystalline silicon, amorphous silicon, microcrystalline silicon, nanocrystalline silicon and silicon oxide, and its N-type doping 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 single crystal silicon, polycrystalline silicon, amorphous silicon, microcrystalline silicon, nanocrystalline silicon and silicon oxide, and its P-type doping element can be one or more of boron, aluminum, gallium, indium, thallium, carbon, and nitrogen. The thickness of the first doped layer and the second doped layer can be set as needed, for example, 3-3000nm.

[0123] The first dielectric layer and the second dielectric layer can be one or more of oxide, nitride, oxynitride, halide, carbide, silicon, and their thickness can be set as needed, for example, 0-10nm. 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.

[0124] The insulating layer may be one or more of oxide, nitride, oxynitride, halide, carbide, silicon, and its thickness may be set as required, for example, 0-5000 nm. Preferably, the insulating layer may be one or more of phosphosilicate glass, borosilicate glass, aluminosilicate glass, gallium silicon glass, silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, silicon carbide, amorphous silicon, etc.

[0125] The surface passivation layer can be one or more of oxide, nitride, oxynitride, halide, carbide, silicon, and its thickness can be set as needed, for example, 0-1000nm. 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, nanocrystalline silicon, etc.

[0126] Unless there are technical obstacles or contradictions, the various technical features disclosed in this application can be freely combined to form additional embodiments, and these additional embodiments are all within the protection scope of this application.

[0127] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "an example", "some embodiments", or "preferred embodiment" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0128] The embodiments of the present invention are described in detail above. However, aspects of the present invention are not limited to the above embodiments. Various modifications and substitutions may be applied to the above embodiments without departing from the scope of the present invention.

Claims

1. A back contact battery, characterized in that: include: A semiconductor substrate, a first doping layer, a second doping layer and an electrode contact portion, wherein the electrode contact portion is disposed on the first doping layer; The main body of the first doping layer and the main body of the second doping layer are alternately and spacedly distributed on the backlight surface of the semiconductor substrate, the first region of the first doping layer and the first region of the second doping layer are electrically connected, and the first doping layer and the second doping layer have opposite conductivity types; Wherein, at least one recessed structure is formed on the backlight surface of the semiconductor substrate, and the at least one recessed structure is arranged between the electrode contact portion and the electrical connection portion.

2. The back contact cell according to claim 1, characterized in that: The at least one recessed structure enables a transmission distance of carriers between the second region of the first doping layer and the second region of the second doping layer in the semiconductor substrate to be shorter than a preset distance.

3. The back contact cell according to claim 1, characterized in that: Along a direction away from the backlight surface of the semiconductor substrate, a main body of the first doping layer is higher than or flush with a main body of the second doping layer, and the at least one recessed structure is disposed below the first doping layer.

4. The back contact cell according to claim 3, characterized in that: The first region stack of the second doped layer is arranged on the first region of the first doped layer, and an insulating layer is arranged between the stacks, which are electrically connected at the side butt surfaces of the stacks, and the at least one recessed structure is arranged below the stacks.

5. The back contact cell according to claim 1, characterized in that: Along a direction away from the backlight surface of the semiconductor substrate, a main body of the first doping layer is higher than a main body of the second doping layer, and the at least one recessed structure is disposed below the second doping layer.

6. The back contact cell according to claim 1, characterized in that: Along the direction away from the backlight surface of the semiconductor substrate, the main body of the first doped layer is higher than or flush with the main body of the second doped layer, the at least one recessed structure is a plurality of recessed structures, the first part of the plurality of recessed structures is located below the first doped layer, and the second part of the plurality of recessed structures is located below the second doped layer.

7. The back contact cell according to claim 1, characterized in that: The distance between the at least one recessed structure and the electrical connection point is less than or equal to the distance between the electrode contact portion and the electrical connection point.

8. The back contact cell according to claim 1, characterized in that The longitudinal section of the at least one recessed structure along the thickness direction of the semiconductor substrate has an inverted trapezoidal shape; and / or the depth of the at least one recessed structure is h, 0.5 μm<h<5 μm.

9. The back contact cell according to any one of claims 1 to 8, characterized in that The at least one recessed structure is a plurality of recessed structures that are partially or completely continuous.

10. The back contact cell according to claim 9, characterized in that: The plurality of partially continuous or fully continuous recessed structures include a plurality of recessed structure groups, wherein each of the plurality of recessed structure groups includes a plurality of fully continuous or partially continuous recessed structures in the same direction.

11. The back contact cell according to claim 10, characterized in that: The recessed structures included in the plurality of recessed structure groups are parallel to each other; or, The angles between the recessed structures included in the plurality of recessed structure groups are less than or equal to 50°.

12. The back contact cell according to claim 10, characterized in that: The recessed structures included in a first recessed structure group among the plurality of recessed structure groups are along an extension direction of a main body portion of the first doping layer or a main body portion of the second doping layer.

13. The back contact cell according to claim 10, characterized in that The recessed structures included in a first recessed structure group among the plurality of recessed structure groups are arranged in a direction in which the main body of the first doping layer and the main body of the second doping layer are alternately spaced.

14. The back contact cell according to claim 9, characterized in that: The length of the partially or completely continuous plurality of recess structures is greater than or equal to the length of the electrical connection along the extension direction of the main body of the first doping layer or the main body of the second doping layer.

15. The back contact cell according to claim 9, characterized in that: The depths of the partially or completely continuous plurality of recessed structures are the same or different.

16. A photovoltaic module, characterized in that: The photovoltaic module comprises a cover plate, a back plate, and a back contact cell disposed between the cover plate and the back plate, wherein the back contact cell is the back contact cell according to any one of claims 1 to 15.

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