Solar cell, cell module and photovoltaic system

Abstract

The invention is applicable to the field of photovoltaic technology, and provides a solar cell, a cell assembly and a photovoltaic system, first areas and second areas on a backlight surface of the solar cell are alternately distributed, are separated by groove areas, and are connected through connecting areas. A first polarity doping layer is laminated on the first region and is provided with a first edge and a second edge; a second polarity doped layer is stacked on the second region and the connection region, the second polarity doped layer is provided with a third edge, and the first polarity doped layer and the second polarity doped layer are in composite contact in the connection region. The first edge and the third edge are opposite on two sides of the groove area, the second edge is close to the composite contact position, and the projection distance from the second edge to the extension line of the third edge is smaller than the projection distance from the first edge to the third edge, so that the distances from the composite contact position to the first area and the second area are relatively balanced. A carrier transmission path is optimized, so that carriers of the first polarity doping layer can reach the second polarity doping layer more quickly, recombination is reduced, collection efficiency is improved, and energy loss is reduced.

Description

Technical Field

[0001] The invention belongs to the field of photovoltaic technology, and in particular relates to a solar cell, a cell assembly and a photovoltaic system. Background Art

[0002] As one of the most abundant renewable energy sources, solar energy has great development potential and application prospects. Solar cells are the core devices that directly convert solar energy into electrical energy and are the key technology to achieve efficient use of solar energy. Photoelectric conversion efficiency refers to the proportion of solar cells converting incident light energy into electrical energy and is the core indicator for measuring the performance of solar cells. Improving the photoelectric conversion efficiency can increase the power output per unit area and reduce the cost of power generation.

[0003] At present, the photoelectric conversion efficiency of commercial silicon-based solar cells is about 20%~25%. Improving the photoelectric conversion efficiency of solar cells is an important part of solar cell research and development. Improving the photoelectric conversion efficiency can increase the power output per unit area, reduce the cost of power generation, and thus shorten the investment recovery period, enhance market competitiveness, and promote the rapid development of the photovoltaic industry. Therefore, improving the photoelectric conversion efficiency of solar cells not only has important economic, environmental and technical significance, but is also the key to promoting the sustainable development of the photovoltaic industry. Summary of the invention

[0004] The present invention provides a solar cell, a cell assembly and a photovoltaic system, aiming to improve the photoelectric conversion efficiency of the solar cell and solve the problem of low photoelectric conversion efficiency of the solar cell.

[0005] The present invention is achieved in that a solar cell comprises: A silicon substrate, wherein the silicon substrate has a backlight surface and a light-facing surface that are oppositely arranged, a first region and a second region are arranged on the backlight surface of the silicon substrate, the first region and the second region are arranged alternately, adjacent first regions and second regions are separated by a groove region, and a connection region is arranged between the first region and the second region to connect the first region and the second region; A first polarity doped layer stacked on the first region, wherein the first polarity doped layer has a first edge and a second edge; A second polarity doped layer is stacked on the second region and the connection region, the second polarity doped layer and the first polarity doped layer are in composite contact in the connection region, and the second polarity doped layer in the second region has a third edge; Among them, the plane where the second area is located is the first plane, the first edge and the third edge are arranged opposite to each other on both sides of the groove area, the second edge is close to the composite contact position of the second polarity doping layer and the first polarity doping layer, and the projection distance of the extension line from the second edge to the third edge on the first plane is smaller than the projection distance from the first edge to the third edge on the first plane.

[0006] Optionally, the third edge is flush with an edge of the second region.

[0007] Optionally, the third edge is at a preset distance from the edge of the second area.

[0008] Optionally, a first notch recessed toward the first region is provided between the first region and the groove region of the silicon substrate of the first region, the first notch having a first side wall and a second side wall, the first side wall being farther away from the light-facing surface than the second side wall, and the first side wall and the surface of the first region having a first angle; The distances between the surfaces of the second region and the connection region and the bottom of the groove region are smaller than the distance between the surface of the first region and the bottom of the groove region; a second notch is provided between the first region and the connection region and is recessed toward the first region; the second notch has a third sidewall and a fourth sidewall; the third sidewall is further away from the light-facing surface than the fourth sidewall; and a second angle is formed between the second sidewall and the surface of the first region; The first angle is smaller than the second angle.

[0009] Optionally, the second side wall and the bottom of the groove area form a first bottom edge; the fourth side wall and the surface of the connection area form a second bottom edge; the second area and the bottom of the groove area have a third bottom edge; A projection distance from the first bottom edge to the third bottom edge on the first plane is greater than a projection distance from the second bottom edge to the third bottom edge on the first plane.

[0010] Optionally, at a first preset position of the groove region, along the arrangement direction of the first region and the second region, the first polarity doped layer has a first extension portion extending above the groove region, and an edge of the first extension portion is the first edge; At a second preset position of the connection region, along the arrangement direction of the first region and the second region, the first polarity doped layer has a second extension portion extending above the groove region, and an edge of the second extension portion is the second edge.

[0011] Optionally, a length of the first extension portion extending outward is greater than a length of the second extension portion extending outward.

[0012] Optionally, the protruding length of the first extension portion is 0.2-5 μm.

[0013] Optionally, the protruding length of the second extension portion is 0.1-3 μm.

[0014] Optionally, the second polarity doped layer is stacked in the connection area, and at the second preset position, the second polarity doped layer has a first wrapping portion, and the first wrapping portion is stacked to cover the second extension portion and is in composite contact with the second extension portion.

[0015] Optionally, it further includes a first dielectric layer and a second dielectric layer; The first dielectric layer is stacked and arranged in the first region, and the first polarity doped layer is stacked and arranged on the first dielectric layer; The first extension portion has a first surface facing the groove region and a second surface facing away from the groove region; The second dielectric layer is stacked in the second region and the connection region; A third dielectric layer is disposed on at least part of the first surface, wherein the third dielectric layer has a tunneling function; The second polarity doped layer is stacked on the second dielectric layer and the third dielectric layer, and the second polarity doped layer on the third dielectric layer is connected to the second polarity doped layer on the second dielectric layer.

[0016] Optionally, at the second preset position, the first wrapping portion extends to cover the second dielectric layer and wraps around an end of the first extending portion and extends to cover the second surface of the first extending portion.

[0017] Optionally, at the second preset position, the first wrapping portion wraps around side walls on both sides of the end portion of the first extending portion.

[0018] Optionally, an insulating layer is provided between the first wrapping portion and the second surface.

[0019] Optionally, the insulating layer has a third extension portion protruding from the second extension portion along an extension direction of the first extension portion.

[0020] Optionally, the first surface and the second surface intersect at an end of the first extending portion to form a tip portion, and the first surrounding portion surrounds the tip portion.

[0021] Optionally, a hole is formed at the end of the tip portion.

[0022] Optionally, the distance from the surface of the first polarity doped layer to the light-facing surface is H1, the distance from the surface of the second polarity doped layer in the second region to the light-facing surface is H2, and the distance from the surface of the groove region to the light-facing surface is H3, H1>H2>H3.

[0023] The present invention also provides a battery assembly, comprising the above-mentioned solar cell.

[0024] The present invention also provides a photovoltaic system, comprising the above-mentioned battery assembly.

[0025] The beneficial effects achieved by the present invention are that the first area and the second area on the backlight surface of the solar cell are alternately distributed, separated by the groove area, and connected by the connection area. A first polarity doped layer is stacked on the first area, which has a first edge and a second edge; a second polarity doped layer is stacked on the second area and the connection area, which has a third edge, and the two are in composite contact in the connection area. The first and third edges are opposite to each other on both sides of the groove area, and the second edge is close to the composite contact position. The projection distance of the extended line from the second edge to the third edge is less than the projection distance from the first edge to the third edge, so that the distance from the composite contact position to the first area and to the second area is relatively balanced. The carrier transmission path is optimized, so that the carriers of the first polarity doped layer can reach the second polarity doped layer faster, reducing recombination, improving collection efficiency, and reducing energy loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the first structure of the solar cell provided by the present invention; Figure 2 This is a second structural schematic diagram of a solar cell provided by the present invention; Figure 3 This is a third structural schematic diagram of the solar cell provided by the present invention; Figure 4 This is a fourth structural schematic diagram of a solar cell provided by the present invention; Figure 5 This is a schematic diagram of a cross-sectional structure of a solar cell provided by the present invention; Figure 6 It is the enlarged view of point A; Figure 7 is another cross-sectional structural schematic diagram of the solar cell provided by the present invention; Figure 8 This is a schematic diagram of the structure of a silicon substrate provided by the present invention; Fig. 9 It is a top-view microscope magnified view of the solar cell provided by the present invention.

[0027] Description of reference numerals: 100, solar cell; 110, silicon substrate; 101, first region; 102, second region; 103, groove region; 104, connection region; 111, first notch; 1111, first side wall; 1112, second side wall; 112, second notch; 1121, third side wall; 1122, fourth side wall; 113, first bottom edge; 114, second bottom edge; 115, third bottom edge; 120, first polarity functional layer group; 121, first polarity functional layer group; a dielectric layer; 122, a first polarity doped layer; 1221, a first extension; 1222, a second extension; 1222.1, a first surface; 1222.2, a second surface; 1222.3, a tip; 130, a second polarity functional layer group; 131, a second dielectric layer; 132, a second polarity doped layer; 1321, a first wrapping portion; 140, an insulating layer; 141, a third extension; 150, a passivation layer; 160, a third dielectric layer; 1001, first boundary line; 1002, second boundary line; 1003, third boundary line; 1004, first edge; 1005, second edge; 1006, third edge. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. In addition, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] In the description of the present invention, it is necessary to understand that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0030] 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.

[0031] 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, an electrical connection, or mutual communication; 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.

[0032] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0033] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the examples of various specific processes and materials provided by the present invention, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0034] The present invention alternately distributes the first and second regions on the backlight surface of the solar cell, which are separated by the groove region and connected by the connection region. A first polarity doped layer is stacked on the first region, which has a first edge and a second edge; a second polarity doped layer is stacked on the second region and the connection region, which has a third edge, and the two are in composite contact in the connection region. The first and third edges are opposite to each other on both sides of the groove region, the second edge is close to the composite contact position, and the projection distance from the second edge to the edge of the silicon substrate of the second region is less than the projection distance from the first edge to the third edge, so that the distance from the composite contact position to the first region and to the second region is relatively balanced. The carrier transmission path is optimized, so that the carriers of the first polarity doped layer can reach the second polarity doped layer faster, reducing recombination, improving collection efficiency, and reducing energy loss.

[0035] Example like Figures 1 to 8As shown, this embodiment provides a solar cell 100, including: A silicon substrate 110, wherein the silicon substrate 110 has a backlight surface and a light-facing surface that are oppositely arranged, a first region 101 and a second region 102 are arranged on the backlight surface of the silicon substrate 110, the first regions 101 and the second regions 102 are arranged alternately, adjacent first regions 101 and second regions 102 are separated by a groove region 103, and a connection region 104 is arranged between the first region 101 and the second region 102 to connect the first region 101 and the second region 102; A first polarity doping layer 122 is stacked on the first region 101, and the first polarity doping layer 122 has a first edge 1004 and a second edge 1005; A second polarity doping layer 132 is stacked on the second region 102 and the connection region 104 . The second polarity doping layer 132 and the first polarity doping layer 122 are in composite contact in the connection region 104 . The second polarity doping layer 132 disposed in the second region 102 has a third edge 1006 . Among them, the plane where the second region 102 is located is the first plane, the first edge 1004 and the third edge 1006 are arranged opposite to each other on both sides of the groove region 103, the second edge 1005 is close to the composite contact position of the second polarity doping layer 132 and the first polarity doping layer 122, and the projection distance of the extension line from the second edge 1005 to the third edge 1006 on the first plane is smaller than the projection distance from the first edge 1004 to the third edge 1006 on the first plane.

[0036] The silicon substrate 110 has two main surfaces, a light-facing surface and a backlight surface. The light-facing surface directly faces the sunlight, while the backlight surface is the other side. The two surfaces are arranged opposite to each other.

[0037] Two different areas are arranged on the backlight surface of the silicon substrate 110, namely, the first area 101 and the second area 102, and the two areas are arranged alternately. Specifically, a plurality of first areas 101 and a plurality of second areas 102 are arranged alternately along the first direction, and the first area 101 and the second area 102 both extend along the second direction, and the second direction intersects the first direction. The first area 101 and the second area 102 may be arranged alternately along the lateral direction of the silicon substrate 110 and both extend along the longitudinal direction, that is, the first direction may be the lateral direction of the back contact battery, and the second direction may be the longitudinal direction of the back contact battery, and the two are perpendicular to each other. Of course, in other embodiments, the first direction and the second direction may also be other directions, for example, the two may be the diagonal directions of the silicon substrate 110, respectively, which is not limited here. The first area 101 and the second area 102 do not overlap each other, and the first area 101 and the second area 102 are arranged adjacent to each other.

[0038] A first polarity functional layer group 120 is disposed in the first region 101. The first polarity functional layer group 120 generally includes multiple layers with different functions, such as a doping layer, a conductive layer, a tunneling layer, etc. These functional layers work together to make the first polarity functional layer group 120 show polarity. A second polarity functional layer group 130 is disposed in the second region 102. The second polarity functional layer group 130 generally also includes multiple layers with different functions, such as a doping layer, a conductive layer, a tunneling layer, etc. These functional layers work together to make the second polarity functional layer group 130 show polarity. The polarities of the first polarity functional layer group 120 and the second polarity functional layer group 130 are different. Specifically, the first polarity functional layer group 120 may be a P-type functional layer group, and the second polarity functional layer group 130 may be an N-type functional layer group, or the first polarity functional layer group 120 may be an N-type functional layer group, and the second polarity functional layer group 130 may be a P-type functional layer group. The first polarity functional layer group 120 and the second polarity functional layer group 130 form regions with different electrical characteristics, supporting the formation of a PN junction and the separation of carriers.

[0039] A groove region 103 is set between the first region 101 and the second region 102. The groove region 103 is a region where the groove is set. Compared with the surfaces of the first region 101 and the second region 102, the groove region 103 is concave, and the first region 101 and the second region 102 are spatially separated to achieve electrical isolation between the first region 101 and the second region 102, thereby avoiding current interference between the adjacent first region 101 and the second region 102.

[0040] The connection region 104 is arranged between the first region 101 and the second region 102, and serves to connect the two. A groove region 103 is arranged between the adjacent first region 101 and the second region 102, and is used to isolate the first region 101 and the second region 102. The connection region 104 is a portion of the second region 102 extending toward the first region 101, that is, the second region 102 extends toward the first region 101 to form the connection region 104, and is arranged between the first region 101 and the second region 102, and is used to connect the first region 101 and the second region 102 isolated by the groove region 103, that is, no groove is arranged in the connection region 104, and the first region 101 and the second region 102 are connected.

[0041] At the second preset position of the connection region 104, along the arrangement direction of the first region 101 and the second region 102, at least part of the functional layers in the first polarity functional layer group 120 have a protruding portion extending above the connection region 104. One or more functional layers in the first polarity functional layer group 120 have a protruding portion, and the protruding portion is placed above the connection region 104. It can be understood that the first polarity functional layer group 120 is arranged on the surface of the first region 101, and the protruding portion is placed above the connection region 104, that is, the surface of the first region 101 is higher than the surface of the connection region 104.

[0042] The second polarity functional layer group 130 is stacked in the connection region 104. Specifically, the second polarity functional layer group 130 stacked in the second region 102 extends toward the connection region 104 and is stacked in the connection region 104. At the second preset position, the second polarity functional layer group 130 has a wrapping portion, which is stacked and covered on the protruding portion of the first polarity functional layer group 120, and extends to cover the first polarity functional layer group 120. The protruding portion has a surface facing the connection region 104, a surface facing away from the connection region 104, and a side wall connecting the two surfaces. The second polarity doped layer 132 is stacked on the bottom surface of the connection region 104 and the side wall between the connection region 104 and the first region 101, and extends and stacks on the protruding portion, that is, the second polarity doped layer 132 wraps and stacks on the surface of the protruding portion facing the connection region 104, the surface facing away from the connection region 104, and the side wall connecting the two surfaces. At least part of the wrapping portion forms a composite contact with the first polarity doped layer 122. Specifically, the wrapping portion may form a composite contact with the surface of the first polarity doped layer 122 facing the connection area 104, or the wrapping portion may form a composite contact with the surface of the first polarity doped layer 122 facing the connection area 104 and the side wall connecting the two surfaces, or the wrapping portion may form a composite contact with other positions of the first polarity doped layer 122, which is not limited here.

[0043] The first polarity functional layer group 120 includes a first polarity doped layer 122, and the second polarity functional layer group 130 includes a second polarity doped layer 132. The polarities of the first polarity doped layer 122 and the second polarity doped layer 132 are different. Specifically, the first polarity doped layer 122 may be a P-type doped layer, and the second polarity doped layer 132 may be an N-type doped layer. The corresponding polarity of the first polarity functional layer group 120 is P-type, and the polarity of the second polarity functional layer group 130 is N-type. Alternatively, the first polarity doped layer 122 may be an N-type doped layer, and the second polarity doped layer 132 may be a P-type doped layer. The corresponding polarity of the first polarity functional layer group 120 is N-type, and the polarity of the second polarity functional layer group 130 is P-type.

[0044] As shown in Figure 9, the edge of the wrapped portion closest to the connection area 104 is the first boundary line 1001, and the wrapped portion is wrapped and stacked on the protruding portion, that is, the wrapped portion is stacked on the surface of the protruding portion facing the connection area 104, the surface facing away from the connection area 104 and the side wall connecting the two surfaces, and the outer contour of the wrapped portion stacked on the side wall connecting the two surfaces (the contour facing away from the side wall) is the first boundary line 1001.

[0045] The edge of the wrapping portion farthest from the connection region 104 is the second boundary line 1002 . The wrapping portion extends to cover the first polarity functional layer group 120 . The edge extending toward the first region 101 is far from the connection region 104 and is the second boundary line 1002 .

[0046] The undulation of the first boundary line 1001 is greater than that of the second boundary line 1002. The undulation is an indicator used to describe the irregularity or fluctuation of the edge of an object. In the context of the solar cell 100 structure, the undulation is specifically used to measure the irregular shape characteristics of the first boundary line 1001 and the second boundary line 1002 of the surrounding part.

[0047] For the edge of the wrapping part, it is not an absolutely smooth and straight line, but has ups and downs and twists and turns. The greater the undulation, the more obvious the ups and downs and twists and turns of the edge, the more irregular the line and the more volatile it is; the smaller the undulation, the smoother the edge is and the closer it is to a straight line.

[0048] The large undulation of the first boundary line 1001 increases the contact area between the second polarity functional layer group 130 and the external environment (such as air, packaging materials, etc.). This larger contact area is conducive to improving the electric field distribution on the battery surface, so that photogenerated carriers (electrons and holes) can be more effectively collected in the second polarity functional layer group 130. When the battery is working, more carriers can enter the second polarity functional layer group 130 through this irregular boundary and then be transmitted to the electrode, thereby increasing the short-circuit current of the battery and improving the photoelectric conversion efficiency.

[0049] The first boundary line 1001 with large undulation can also reduce the recombination of carriers at the boundary to a certain extent. The irregular surface structure makes the movement path of carriers more complicated, reduces the probability of their meeting and recombination, and further improves the collection efficiency of carriers.

[0050] The irregular shape of the first boundary line 1001 can also guide the current to be more evenly distributed in the second polarity functional layer group 130. Compared with a smooth edge, an edge with a large undulation can disperse the current, avoid the current from being concentrated in certain specific locations, and reduce the risk of local overheating. Uniform current distribution helps to improve the stability and reliability of the battery and extend the service life of the battery.

[0051] like Figure 2 As shown, specifically, the first polarity doped layer 122 is stacked on the first region 101, and the first polarity doped layer 122 may be in direct contact with the first region 101 of the silicon substrate 110, or other functional layers, such as a tunneling functional layer, may be provided between the first polarity doped layer 122 and the silicon substrate 110. The first polarity doped layer 122 has two edges, namely a first edge 1004 and a second edge 1005, the edge facing the groove region 103 is the first edge 1004, and the edge facing the connection region 104 is the second edge 1005.

[0052] The second polarity doped layer 132 is stacked on the second region 102 and the connection region 104. The second polarity doped layer 132 may be in direct contact with the second region 102 and the connection region 104 of the silicon substrate 110, or other functional layers, such as a tunneling functional layer, may be provided between the second polarity doped layer 132 and the silicon substrate 110. The second polarity doped layer 132 in the second region 102 has a third edge 1006, and the third edge 1006 is on the other side of the trench region 103 and is arranged opposite to the first edge 1004 on one side of the trench region 103.

[0053] The second polarity doped layer 132 and the first polarity doped layer 122 form a composite contact in the connection region 104. "Compound contact" means that there is no insulation between the first polarity functional layer group 120 and the second polarity functional layer group 130, but leakage conduction forms a leakage channel. Specifically, the doped layer in the first polarity functional layer group 120 and the doped layer in the second polarity functional layer group 130 may be in direct contact to form a leakage channel, or tunneling may be achieved through other dielectric layers to achieve the function of composite contact, which is not limited here.

[0054] The plane where the second region 102 is located is the first plane. The actual surface of the second region 102 may have concave and convex microstructures and is not an absolute plane, but the first plane is a rough concept of a plane. It can be understood that, on a macro scale, a plane is determined based on the overall distribution of the second region 102 and ignoring the tiny concave and convex undulations on its surface. This plane provides a unified reference benchmark for the subsequent description of the distance relationship between the edges.

[0055] The projection distance of the extension line from the second edge 1005 to the third edge 1006 on the first plane is smaller than the projection distance from the first edge 1004 to the third edge 1006 on the first plane. In the solar cell 100 structure, the first edge 1004, the second edge 1005 and the third edge 1006 are substantially parallel, and when judging the distance between the edges, the undulations of the surface are ignored, and the projections of the edges on the first plane are approximately regarded as straight lines along the extension direction of the edges.

[0056] The projection of the extension line of the third edge 1006 on the first plane is, that is, the extension line of the projection of the third edge 1006 on the first plane.

[0057] On the first plane, the projection lines of each edge are parallel or approximately parallel (the angle difference is small, usually the angle difference is not greater than 2°). It can be understood that the projection lines of each edge may not be absolute straight lines, and each projection line is approximately regarded as a straight line. The projection distance of the extension line from the second edge 1005 to the third edge 1006 on the first plane is recorded as L1. Since the third edge 1006 and the second edge 1005 are not in a relative position, the two are staggered. The projection distance from the second edge 1005 to the third edge 1006 on the first plane is also the projection distance from the extension line from the second edge 1005 to the third edge 1006 on the first plane, that is, the vertical distance between the projection line of the second edge 1005 and the projection line of the third edge 1006 on the first plane. The projection distance from the first edge 1004 to the third edge 1006 on the first plane is the vertical distance between the projection lines from the first edge 1004 to the third edge 1006 on the first plane, recorded as L2, L1<L2.

[0058] It can be understood that the perpendicular distance is also the shortest distance. Find the common perpendicular line of two parallel straight lines (a straight line that intersects both straight lines perpendicularly). The length of the common perpendicular line segment is the perpendicular distance between the two parallel straight lines.

[0059] The projection distance of the extension line from the second edge 1005 to the third edge 1006 on the first plane is smaller than the projection distance from the first edge 1004 to the third edge 1006 on the first plane, which means that the composite contact position is relatively closer to the first area 101, and the distance between the first area 101 and the second area 102 reaches a relatively balanced state through this setting.

[0060] In the solar cell 100, the recombination of carriers (electrons and holes) is one of the important factors affecting the efficiency of the cell. When the distance between the recombination contact position and the first region 101 and the second region 102 is balanced, the transmission path of the carriers can be optimized. Since the recombination contact position is closer to the first region 101, the carriers generated by the first polarity doping layer 122 can be transmitted to the second polarity doping layer 132 through the recombination contact region more quickly, reducing the probability of the carriers recombining with other impurities or defects during the transmission process, thereby improving the collection efficiency of the carriers and reducing energy loss.

[0061] In this embodiment, the first region 101 and the second region 102 are alternately distributed on the backlight surface of the solar cell 100, separated by the groove region 103, and connected by the connection region 104. The first polarity doping layer 122 is stacked on the first region 101, which has a first edge 1004 and a second edge 1005; the second polarity doping layer 132 is stacked on the second region 102 and the connection region 104, and has a third edge 1006, and the two are in composite contact in the connection region 104. The first and third edges are opposite to each other on both sides of the groove region 103, and the second edge 1005 is close to the composite contact position. The projection distance from the second edge 1005 to the edge of the silicon substrate 110 of the second region 102 is less than the projection distance from the first edge 1004 to the third edge 1006, so that the distance from the composite contact position to the first region 101 and to the second region 102 is relatively balanced. This optimizes the carrier transmission path, allowing the carriers from the first polarity doping layer 122 to reach the second polarity doping layer 132 more quickly, thereby reducing recombination, improving collection efficiency, and reducing energy loss.

[0062] like Figure 1 As shown, in some embodiments, the third edge 1006 is flush with the edge of the second region 102 .

[0063] The groove region 103 is disposed adjacent to the second region 102 , and the edge of the second region 102 is also the edge of the groove region 103 , which is the boundary line between the surface of the second region 102 on the silicon substrate 110 and the groove region 103 .

[0064] The third edge 1006 is the boundary of the second polarity doped layer 132 facing the groove region 103 . The two edges are flush, which means that the two boundaries are at the same position in space, that is, the projection distance between the third edge 1006 and the edge of the second region 102 on the first plane is 0.

[0065] This structural design can improve the compactness and regularity of the battery's internal structure, facilitate uniform current conduction, reduce resistance losses, and thus improve the battery's photoelectric conversion efficiency.

[0066] like Figure 2 As shown, in some embodiments, the third edge 1006 is a preset distance away from the edge of the second region 102 .

[0067] The third edge 1006 is at a preset distance L3 from the edge of the second region 102 . The second polarity doped layer 132 has no portion extending above the trench region 103 . Therefore, the distance between the third edge 1006 and the edge of the second region 102 is the distance L3 that the third edge 1006 is retracted from the edge of the second region 102 .

[0068] By setting the second polarity doping layer 132 to have a preset distance L3 from the edge of the groove area 103 (that is, there is a platform area between the second polarity doping layer 132 and the groove area 103), the outermost layer of the backlight surface is usually covered with a passivation film layer. The formed platform area can increase the mobile hydrogen content of the passivation film layer in the local upper layer of the space charge region, thereby achieving enhanced hydrogen passivation in this area, reducing the recombination of the space charge region, and improving battery performance.

[0069] like Figure 8 As shown, in some embodiments, the silicon substrate 110 of the first region 101 has a first notch 111 recessed toward the first region 101 between the first region 101 and the groove region 103, the first notch 111 has a first sidewall 1111 and a second sidewall 1112, the first sidewall 1111 is farther away from the light-facing surface than the second sidewall 1112, and the first sidewall 1111 and the surface of the first region 101 have a first angle; The distance between the surface of the second region 102 and the connection region 104 and the bottom of the groove region 103 is smaller than the distance between the surface of the first region 101 and the bottom of the groove region 103. A second notch 112 is provided between the first region 101 and the connection region 104 and is recessed toward the first region 101. The second notch 112 has a third sidewall 1121 and a fourth sidewall 1122. The third sidewall 1121 is further away from the light-facing surface than the fourth sidewall 1122. The second sidewall 1112 and the surface of the first region 101 have a second angle. The first angle is smaller than the second angle.

[0070] The distance between the surface of the second region 102 and the connection region 104 and the bottom of the groove region 103 is smaller than the distance between the surface of the first region 101 and the bottom of the groove region 103, that is, the height of each region on the silicon substrate 110 is stepped, and there is a height difference between each region. The bottom of the groove region 103 is the lowest, the surface of the second region 102 and the connection region 104 is higher than the bottom of the groove region 103, and the surface of the first region 101 is higher than the surface of the second region 102 and the connection region 104.

[0071] The silicon substrate 110 of the first region 101 has a first notch 111 that is recessed toward the first region 101 between the first region 101 and the groove region 103, and the region has a first sidewall 1111 and a second sidewall 1112. The first notch 111 is a lateral notch, formed by the inward recess of the sidewall between the groove region 103 and the first region 101, and the intersection of the first sidewall 1111 and the second sidewall 1112 is the notch bottom of the first notch 111. The first sidewall 1111 is farther away from the light-facing surface than the second sidewall 1112, that is, the first sidewall 1111 is closer to the surface of the first region 101 than the second sidewall 1112, and the first sidewall 1111 and the surface of the first region 101 form a first angle.

[0072] The silicon substrate 110 of the first region 101 has a second notch 112 that is recessed toward the first region 101 between the first region 101 and the connection region 104, and the region has a third sidewall 1121 and a fourth sidewall 1122. The second notch 112 is a lateral notch, formed by the inward recess of the sidewall between the connection region 104 and the first region 101, and the intersection of the third sidewall 1121 and the fourth sidewall 1122 is the notch bottom of the second notch 112. The third sidewall 1121 is farther away from the light-facing surface than the fourth sidewall 1122, that is, the third sidewall 1121 is closer to the surface of the first region 101 than the fourth sidewall 1122, and the third sidewall 1121 and the surface of the first region 101 form a second angle.

[0073] The first angle is smaller than the second angle, the angle formed by the first side wall 1111 and the surface of the first region 101 is smaller than the angle formed by the third side wall 1121 and the surface of the first region 101 , and the depth of the first notch 111 is greater than the depth of the second notch 112 .

[0074] The greater depth of the first notch 111 means that the spatial structure inside it is more complex. When light hits the surface of the solar cell 100 and enters the first notch 111, the light will experience more reflections inside the notch due to the depth of the notch. Each reflection gives the light more opportunities to be absorbed by the battery material, which is equivalent to increasing the effective absorption area of ​​the battery for light. For example, light that originally directly hits the surface of the battery may only undergo one absorption process, but after multiple reflections inside the first notch 111, the light can be absorbed at different angles and positions, so that more light can be used by the battery.

[0075] The deeper first notch 111 can also expand the angle range of light receiving of the battery. Light incident at different angles can more easily enter the first notch 111, and compared with a shallow notch or a flat structure, it can capture more light from different directions. In practical applications, the position of the sun will change with time and season, and the incident angle of light will also change accordingly. The deep structure of the first notch 111 can enable the battery to better absorb light under different lighting conditions, further increasing the light absorption area.

[0076] In this embodiment, the angle of the first angle is smaller than the angle of the second angle, and the depth of the first notch 111 is greater than the depth of the second notch 112. The position of the first notch 111 corresponds to the groove area 103, and the light cannot be utilized in the groove area 103. The deeper first notch 111 is conducive to increasing the light absorption area. The second notch 112 corresponds to the connection area 104, and the connection area 104 is stacked with a second polarity doping layer 132, which can absorb and utilize light. The depth of the second notch 112 is shallow, and the light that is not absorbed in the second notch 112 can be absorbed and utilized in the second polarity doping layer 132.

[0077] like Figure 8 As shown, in some embodiments, the second sidewall 1112 and the bottom of the groove region 103 form a first bottom edge 113; the fourth sidewall 1122 and the surface of the connection region 104 form a second bottom edge 114; the second region 102 and the bottom of the groove region 103 have a third bottom edge 115; A projection distance from the first bottom side 113 to the third bottom side 115 on the first plane is greater than a projection distance from the second bottom side 114 to the third bottom side 115 on the first plane.

[0078] The second sidewall 1112 and the bottom of the groove region 103 form a first bottom edge 113, the fourth sidewall 1122 and the surface of the connection region 104 form a second bottom edge 114, the second region 102 and the bottom of the groove region 103 have a third bottom edge 115, and the first bottom edge 113 and the third bottom edge 115 are also two boundaries of the bottom surface of the groove region 103. Usually, the first bottom edge 113, the second bottom edge 114 and the third bottom edge 115 are roughly parallel, and when judging the distance between the bottom edges, the undulations on the surface are ignored, and along the extension direction of each edge, the projection of each edge on the first plane is approximately regarded as a straight line, then the projections of the first bottom edge 113, the second bottom edge 114 and the third bottom edge 115 on the first plane are parallel.

[0079] The projection distance from the first base 113 to the third base 115 on the first plane is denoted as S1, and the projection distance from the second base 114 to the third base 115 on the first plane is denoted as S2, S1>S2.

[0080] S1 corresponds to the groove area 103. The main function of the groove area 103 is to achieve electrical isolation between different areas of the battery to prevent leakage. When S1 is larger, it means that the effective isolation distance of the groove area 103 is longer on the projection plane. Leakage is usually caused by the flow of carriers (electrons or holes) on an unexpected path. The longer isolation distance increases the difficulty of carriers crossing the groove area 103, which is equivalent to increasing the resistance of leakage. It effectively reduces the leakage between different areas inside the battery and improves the stability of the battery's electrical performance.

[0081] S2 corresponds to the connection area 104. The function of the connection area 104 is to realize the electrical connection between different parts of the battery so that the carriers can be smoothly transmitted between different areas. A smaller S2 means that the distance of the connection area 104 is relatively short, and the transmission path of the carriers in the connection area 104 is shorter. A shorter transmission path can reduce the energy loss and recombination probability of the carriers during the transmission process, ensure good electrical contact between different areas of the battery, and reduce the contact resistance. Lower contact resistance is conducive to improving the fill factor and output power of the battery, so that the battery can more efficiently convert light energy into electrical energy output.

[0082] In this embodiment, the projection distance from the first bottom edge 113 to the third bottom edge 115 on the first plane is greater than the projection distance from the second bottom edge 114 to the third bottom edge 115 on the first plane. The isolation performance of the groove area 103 and the contact performance of the connection area 104 are optimized by distance, thereby improving the photoelectric conversion efficiency, electrical performance stability and overall reliability of the solar cell 100.

[0083] like Figure 3 As shown, in some embodiments, at a first preset position of the groove region 103, along the arrangement direction of the first region 101 and the second region 102, the first polarity doping layer 122 has a first extension portion 1221 extending above the groove region 103, and the edge of the first extension portion 1221 is the first edge 1004; At the second preset position of the connection region 104 , along the arrangement direction of the first region 101 and the second region 102 , the first polarity doped layer 122 has a second extension portion 1222 extending above the trench region 103 , and the edge of the second extension portion 1222 is the second side.

[0084] Typically, in the production of the solar cell 100, the second region 102 and the connection region 104 are formed by the first etching, and the groove region 103 is formed by the second etching. Each etching will partially remove the silicon substrate 110 at the corresponding position, so that the surface of the first region 101 is higher than the surfaces of the second region 102 and the connection region 104, and the surfaces of the second region 102 and the connection region 104 are higher than the surface of the groove region 103 (the bottom surface of the groove region).

[0085] At the first preset position of the groove region 103, along the arrangement direction of the first region 101 and the second region 102, the first polarity doped layer 122 extends above the groove region 103 to form a first extension portion 1221, whose edge is the first edge 1004. That is, the projection of the first extension portion 1221 along the vertical direction falls into the groove region 103.

[0086] At the second preset position of the connection region 104, along the arrangement direction of the groove region 103 and the non-groove region 103, the first polarity doped layer 122 extends above the groove region 103 to form a second extension portion 1222, whose edge is the second edge 1005. That is, the projection of the second extension portion 1222 along the vertical direction falls into the connection region 104.

[0087] In this embodiment, the first polarity doped layer 122 has a first extension portion 1221 and a second extension portion 1222. The first extension portion 1221 extends above the groove area 103, and the second extension portion 1222 extends above the connection area 104, thereby increasing the effective light receiving area of ​​the battery, allowing more light to be absorbed by the first polarity doped layer 122, thereby improving the light absorption efficiency, increasing the number of photogenerated carriers generated, and thereby improving the photoelectric conversion efficiency of the battery.

[0088] In some embodiments, the length of the first extension portion 1221 is greater than the length of the second extension portion 1222 .

[0089] When the first polarity doping layer 122 has a second extension 1222, the composite contact of the first polarity doping layer 122 and the second polarity doping layer 132 is at the second extension 1222. The longer first extension 1221 can absorb more light in the groove region 103 and generate more photogenerated carriers, while the shorter second extension 1222 can optimize the carrier transmission path while ensuring a certain light absorption, thereby improving the overall performance of the battery.

[0090] Specifically, the first extension portion 1221 has an extension length of 0.2 to 5 μm. The extension length of the first extension portion 1221 may be 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm, 2.2 μm, 2.4 μm, 2.6 μm, 2.8 μm, 3 μm, 3.2 μm, 3.4 μm, 3.6 μm, 3.8 μm, 4 μm, 4.2 μm, 4.4 μm, 4.6 μm, 4.8 μm, 5 μm, or other values ​​within the range of 0.2 to 5 μm, which are not limited here.

[0091] By controlling the extension length of the first extension portion 1221 to be between 0.2 and 5 μm, the light absorption area can be effectively increased, and the number of photogenerated carriers generated can be increased. At the same time, the probability of carrier recombination during transmission will not be greatly increased due to the extension being too long, thus ensuring that the carriers can be smoothly transmitted to the electrode.

[0092] The second extension portion 1222 has an extension length of 0.1 to 3 μm. The extension length of the first extension portion 1221 can be 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm, 2.2 μm, 2.4 μm, 2.6 μm, 2.8 μm, 3 μm, or other values ​​within 0.1 to 3 μm, which are not limited here.

[0093] By controlling the extension length of the second extension portion 1222 to be between 0.1 and 3 μm, a balance between light absorption and carrier transport can be achieved in the battery groove region 103. A shorter length can reduce unnecessary carrier recombination and work in conjunction with the first extension portion 1221 to make the current distribution inside the battery more reasonable.

[0094] In some embodiments, the second polarity doping layer 132 is stacked in the connection region 104 . At the second preset position, the second polarity doping layer 132 has a first wrapping portion 1321 . The first wrapping portion 1321 is stacked to cover the second extension portion 1222 and is in composite contact with the second extension portion 1222 .

[0095] The second polarity doped layer 132 is stacked in the connection area 104, that is, the second polarity doped layer 132 is stacked on the surface of the connection area 104 and the side wall between the first area 101 and the connection area 104, and has a first wrapping portion 1321 extending and covering the second extension portion 1222, and the first wrapping portion 1321 is in composite contact with the second extension portion 1222.

[0096] The second extension portion 1222 has a surface facing the connection region 104, a surface facing away from the connection region 104, and a side wall connecting the two surfaces. The second polarity doped layer 132 is stacked on the bottom surface of the connection region 104 and the side wall between the connection region 104 and the first region 101, and extends and is stacked on the second extension portion 1222. The first wrapping portion 1321 may be the second polarity doped layer 132 wrapped and stacked on the surface of the second extension portion 1222 facing the connection region 104, the surface facing away from the connection region 104, and the side wall connecting the two surfaces, or the second polarity doped layer 132 wrapped and stacked on the surface of the second extension portion 1222 facing the connection region 104 and the side wall connecting the two surfaces, or the second polarity doped layer 132 only wrapped and stacked on the surface of the second extension portion 1222 facing the connection region 104.

[0097] The first wrapping portion 1321 and the second extension portion 1222 are in composite contact. Specifically, the first wrapping portion 1321 and the second extension portion 1222 may form composite contact on the surface facing the connection area 104, or the first wrapping portion 1321 and the second extension portion 1222 may form composite contact on the surface facing the connection area 104 and the side wall connecting the two surfaces, or the first wrapping portion 1321 and the second extension portion 1222 may form composite contact at other positions. The actual selection can be made according to the structure of the first wrapping portion 1321 and is not limited here.

[0098] The design of the first wrapping portion 1321 increases the contact area between the second polarity doping layer 132 and the second extension portion 1222. A larger contact area means that the resistance of carriers when transmitted between the two is reduced, and the carriers can be transmitted more efficiently, thereby improving the overall conductivity of the battery.

[0099] Figure 5 and Figure 7 As shown, in some embodiments, the solar cell 100 further includes a first dielectric layer 121, a second dielectric layer 131 and a third dielectric layer 160; The first dielectric layer 121 is stacked and disposed in the first region 101, and the first polarity doping layer 122 is stacked and disposed on the first dielectric layer 121; The first extension portion 1221 has a first surface 1222.1 facing the trench region 103 and a second surface 1222.2 facing away from the trench region 103. The second dielectric layer 131 is stacked in the connection region 104 and extends to cover at least a portion of the first surface 1222.1. The portion of the second dielectric layer 131 located on the first surface 1222.1 has a tunneling function. The second polarity doping layer 132 is stacked on the second dielectric layer 131 .

[0100] The first dielectric layer 121 is stacked on the first region 101, and the first polarity doped layer 122 is stacked on the first dielectric layer 121. Specifically, the first dielectric layer 121 and the first polarity doped layer 122 may be in direct contact, or other functional layers may be disposed between the first dielectric layer 121 and the first polarity doped layer 122. The first dielectric layer 121 may be a tunneling layer, such as a silicon oxide tunneling layer or other film layer having passivation and tunneling functions, and its specific type may be selected according to actual conditions, and is not specifically limited here.

[0101] At the second preset position, along the arrangement direction of the connection region 104 and the first region 101 , the first polarity doped layer 122 has a second extension portion 1222 extending above the connection region 104 , and the second extension portion 1222 has a first surface 1222 . 1 facing the connection region 104 and a second surface 1222 . 2 facing away from the connection region 104 .

[0102] The second dielectric layer 131 is stacked in the second region 102 and the connection region 104, and the third dielectric layer 160 is disposed on at least part of the first surface 1222.1, that is, the third dielectric layer 160 covers all or part of the first surface 1222.1. The second dielectric layer 131 is stacked in the connection region 104, and there is a side wall between the connection region 104 and the first region 101. The second dielectric layer 131 can be disposed only on the bottom surface of the connection region 104, or on the bottom surface of the connection region 104 and extending to the side wall between the connection region 104 and the first region 101. Specifically, the second dielectric layer 131 on the side wall between the connection region 104 and the first region 101 can be connected to or disconnected from the third dielectric layer 160, which is not limited here. The third dielectric layer 160 has a tunneling function. The third dielectric layer 160 can be an oxide layer, such as a silicon oxide film layer or other film layer with a passivation function. It has a tunneling function at the portion covering the first surface 1222.1. The specific type can be selected according to actual conditions and is not specifically limited here.

[0103] The second polarity doped layer 132 is stacked on the second dielectric layer 131 and the third dielectric layer 160, and the second polarity doped layer 132 on the third dielectric layer 160 is connected to the second polarity doped layer 132 on the second dielectric layer 131, that is, no matter whether the second dielectric layer 131 and the third dielectric layer 160 are connected or not, the second polarity doped layer 132 stacked on the second dielectric layer 131 and the third dielectric layer 160 is not interrupted. Specifically, the second polarity doped layer 132 may be in direct contact with the second dielectric layer 131 and the third dielectric layer 160, or other functional layers may be disposed between the second polarity doped layer 132 and the second dielectric layer 131 and the third dielectric layer 160, which is not limited here. The second polarity doping layer 132 has a first wrapping portion 1321 . Specifically, the first wrapping portion 1321 wraps around an end portion of the second extending portion 1222 and a second surface 1222 . 2 of the second extending portion 1222 and extends to the first region 101 .

[0104] Specifically, at the second preset position of the connection area 104, the first wrapping portion 1321 can wrap around the first surface 1222.1, the end and the second surface 1222.2 of the entire second extension portion 1222, that is, the first wrapping portion 1321 can extend along the side of the connection area 104 to cover the second dielectric layer 131 and wrap around the end of the second extension portion 1222 and extend to cover the second surface 1222.2 of the second extension portion 1222, and can even extend to cover a portion of the first polarity doped layer 122 arranged on the first area 101. In this case, an insulating medium may be provided between the first wrapping portion 1321 and the second surface 1222.2, for example, a silicon oxide layer, a silicon nitride layer, etc. having an insulating function. When the second dielectric layer 131 only covers a portion of the first surface 1222.1, the first surface 1222.1 not covered by the second dielectric layer 131 is covered by the second polarity doping layer 132, and the second polarity doping layer 132 disposed on the second surface 1222.2 and the second polarity doping layer 132 disposed on the second dielectric layer 131 are continuous and uninterrupted.

[0105] In the present application, the silicon substrate 110 may be a P-type silicon substrate 110 or an N-type silicon substrate 110 , and it may be preferably an N-type silicon substrate 110 , which is not specifically limited herein.

[0106] In a possible embodiment, during the manufacturing process, the silicon substrate 110 may be first cleaned and textured, and then a first dielectric layer 121 may be deposited on the entire backlight surface of the silicon substrate 110, and then a first polarity doping layer 122 may be deposited on the first dielectric layer 121, and then a portion of the first polarity doping layer 122 and the first dielectric layer 121 may be removed by etching or the like, and a portion of the silicon substrate 110 may be removed on the backlight surface at a corresponding position, and the portion not etched is the first region 101, so that the silicon substrate 110 in the first region 101 is There is a height difference between the surface and the surface of the silicon substrate 110 in other areas (the connection area 104, the second area 102 and the groove area 103), so that the first extension portion 1221 of the first polarity doped layer 122 at a preset position extends above the connection area 104. For example, in a possible embodiment, a partial recess may be first formed by laser or etching, and then the area of ​​the recess may be laterally expanded by etching so that the first polarity doped layer 122 has a first extension portion 1221 extending above the connection area 104.

[0107] Subsequently, the second dielectric layer 131 may be deposited on the surface and sidewalls of other regions except the first region 101, and on the first surface 1222.1 of the first extension portion 1221. Then, the second polarity doping layer 132 may be deposited by deposition, so that the second polarity doping layer 132 is stacked and covers the second dielectric layer 131, and has a first wrapping portion 1321 at a preset position, and the first wrapping portion 1321 wraps around the end of the first extension portion 1221 and the second surface 1222.2 of the first extension portion 1221 and extends to the first region 101.

[0108] Finally, the second polarity doping layer 132 and the second dielectric layer 131 in the groove area 103 are removed again by etching or the like, and part of the silicon substrate 110 is removed on the backlight surface at the corresponding position, so that the surface of the silicon substrate 110 in the groove area 103 has a height difference with the surfaces of the silicon substrate 110 in the connection area 104 and the second area 102, thereby forming a groove.

[0109] In some embodiments, the solar cell 100 may further include a first electrode and a second electrode, both of which are metal electrodes. A passivation film layer may also be provided on the backlight surface of the silicon substrate 110, and the passivation film layer covers the entire backlight surface (that is, the passivation film layer, as the outermost film layer, covers all the sub-outer film layers on the backlight surface, and the sub-outer film layers of the first region 101 and the sub-outer film layers of the second region 102 are partially different). The first electrode is located in the first region 101 and penetrates the passivation film layer to form an ohmic contact with the first polarity doping layer 122 and is insulated and isolated from the second polarity doping layer 132. For example, when the first wrapping portion 1321 extends to cover the protruding portion and covers part of the first polarity doping layer 122 on the first region 101, the first electrode may be located at a position where the first polarity doping layer 122 is not wrapped and covered by the first wrapping portion 1321, and the second electrode may be located in the second region 102 and penetrate the passivation film layer to form an ohmic contact with the second polarity doping layer 132.

[0110] like Figure 4 As shown, in some embodiments, at the second preset position, the first wrapping portion 1321 wraps around the side walls on both sides of the end portion of the second extending portion 1222 .

[0111] The second extension portion 1222 has two opposite side walls, and the first wrapping portion 1321 wraps around the side walls on both sides of the end of the second extension portion 1222 , that is, except for the connecting portion between the second extension portion 1222 and the first polarity doping layer 122 , the rest of the protruding portion is completely wrapped by the first wrapping portion 1321 .

[0112] The first wrapping portion 1321 wraps around the sidewalls of both sides of the end of the first extension portion 1221, so that the contact area between the second polarity doping layer 132 and the first extension portion 1221 is greatly increased. More contact area provides more composite contact transmission channels for carriers, further reducing contact resistance.

[0113] In some embodiments, an insulating layer 140 is disposed between the first wrapping portion 1321 and the second surface 1222 . 2 .

[0114] The first wrapping portion 1321 is a part of the second polarity doping layer 132, the second surface 1222.2 is a surface of the first polarity doping layer 122, and the insulating layer 140 is disposed between the first wrapping portion 1321 and the second surface 1222.2, that is, the second polarity doping layer 132 and the first polarity doping layer 122 are stacked at this position, and the insulating layer 140 is disposed between the first polarity doping layer 122 and the second polarity doping layer 132. The insulating layer 140 can isolate the electrical connection between the first polarity doping layer 122 and the second polarity doping layer 132 to avoid unnecessary current leakage and interference.

[0115] In this embodiment, the provision of the insulating layer 140 prevents the unnecessary flow of electrons between the first wrapping portion 1321 and the first extension portion 1221, thereby reducing current leakage. This makes the electric field distribution inside the battery more reasonable, and carriers can be more effectively collected and transmitted to the electrodes, thereby improving the open circuit voltage and fill factor, thereby improving the photoelectric conversion efficiency of the battery.

[0116] In some embodiments, the insulating layer 140 has a third extending portion 141 protruding from the second extending portion 1222 along the arrangement direction of the connecting region 104 and the first region 101 .

[0117] The insulating layer 140 is not only disposed between the first wrapping portion 1321 and the second surface 1222.2, but also has a third extension portion 141 protruding from the second extension portion 1222 along the arrangement direction of the connection region 104 and the first region 101. The third extension portion 141 further enhances the insulation and isolation effect and expands the insulation range.

[0118] Assuming that the length of the second extension portion 1222 is 80 nanometers, the third extension portion 141 of the insulating layer 140 protrudes 20-30 nanometers on the basis of the second extension portion 1222. In this way, current leakage can be better prevented at the junction of the connection region 104 and the first region 101.

[0119] In this embodiment, the third extension portion 141 increases the coverage of the insulating layer 140, especially at the edge of the connection region 104 and the first region 101, reducing the possibility of electric field concentration and current leakage at the edge. This helps to protect the edge structure of the battery, prevent battery performance degradation and shortened life due to edge leakage, thereby improving the reliability and stability of the battery.

[0120] Figure 5 to Figure 7 As shown, in some embodiments, the first surface 1222.1 and the second surface 1222.2 intersect at an end of the first extension portion 1221 to form a tip portion 1222.3, and the first wrapping portion 1321 wraps around the tip portion 1222.3.

[0121] The end of the first extension portion 1221 is pointed. Even if the first wrapping portion 1321 wraps around the tip portion 1222.3, there is only line-surface contact between the first wrapping portion 1321 and the tip of the tip portion 1222.3, which can reduce the contact area between the end of the first extension portion 1221 and the first wrapping portion 1321 and reduce the composite.

[0122] Of course, it can be understood that in some embodiments, the end of the first extension portion 1221 may not form a tip, that is, the first surface 1222.1 and the second surface 1222.2 may be connected through an end face. In this case, the first wrapping portion 1321 may wrap around the end face of the first extension portion 1221. When the first wrapping portion 1321 wraps around the end face of the first extension portion 1221, a dielectric layer may or may not be provided between the end face and the first wrapping portion 1321. In the case of providing a dielectric layer, the dielectric layer may be a film layer such as a metal oxide layer, an intrinsic silicon layer, etc., and is not specifically limited here.

[0123] In some embodiments, a hole is formed at the end of the tip portion 1222.3.

[0124] In this way, the hole formed on the end of the tip portion 1222.3 can reduce the contact area between the first wrapping portion 1321 and the end of the tip portion 1222.3, thereby reducing the composite.

[0125] In some embodiments, the distance from the surface of the first polarity doped layer 122 to the light-facing surface is H1, the distance from the surface of the second polarity doped layer 132 to the light-facing surface is H2, and the distance from the surface of the groove region 103 to the light-facing surface is H3, H1>H2>H3.

[0126] That is, when the solar cell 100 is placed horizontally with the light side facing downward, the surface of the first polarity doped layer 122 is higher than the surface of the second polarity doped layer 132 in the second region 102 , and the surface of the second polarity doped layer 132 in the second region 102 is higher than the surface of the groove region 103 .

[0127] Different distance settings enable light to be better absorbed by different doping layers and regions after entering the battery. H3 is the smallest, and the groove area 103 is closer to the light-facing surface. When light irradiates the battery surface, it first reaches the groove area 103. Although the groove area 103 does not perform photoelectric conversion, it can scatter and refract the light. This can make the propagation path of light inside the battery more complex and diversified, increase the propagation distance of light in the first polarity doping layer 122 and the second polarity doping layer 132, thereby improving the absorption efficiency of these two layers for light.

[0128] The second polarity doping layer 132 is closer to the light-facing surface than the first polarity doping layer 122 (H2

[0129] This embodiment provides a battery assembly including a plurality of solar cells 100 .

[0130] The multiple solar cells 100 in the battery module can be connected in series in sequence to form a battery string. The battery strings can be connected in series, in parallel, or in a combination of series and parallel to achieve current bus output. For example, the connection between the individual battery cells can be achieved by welding welding strips, and the connection between the individual battery strings can be achieved by bus bars.

[0131] The battery assembly may also include a metal frame, a back plate, photovoltaic glass and an adhesive film (not shown in the figure). The adhesive film may be filled between the light-facing surface and the photovoltaic glass, the backlight surface and the back plate of the solar cell 100, and the adjacent cells. As a filler, it may be a transparent colloid with good light transmission and aging resistance. For example, the adhesive film may be an EVA adhesive film or a POE adhesive film. The specific selection may be based on actual conditions and is not limited here.

[0132] Photovoltaic glass can cover the adhesive film on the light-facing surface of the solar cell 100. The photovoltaic glass can be ultra-white glass, which has high light transmittance, high transparency, and excellent physical, mechanical and optical properties. For example, the light transmittance of ultra-white glass can reach more than 92%, which can protect the solar cell 100 without affecting the efficiency of the solar cell 100 as much as possible. At the same time, the adhesive film can bond the photovoltaic glass and the solar cell 100 together, and the presence of the adhesive film can seal and insulate the solar cell 100 and prevent water and moisture.

[0133] ​The backplane can be attached to the adhesive film on the backlight surface of the solar cell 100. The backplane can protect and support the solar cell 100 and has reliable insulation, water resistance and aging resistance. There are multiple options for the backplane, which can usually be tempered glass, organic glass, aluminum alloy TPT composite adhesive film, etc. It can be set according to specific circumstances and is not limited here. The whole composed of the backplane, solar cell 100, adhesive film and photovoltaic glass can be set on a metal frame. The metal frame serves as the main external support structure of the entire battery assembly and can stably support and install the battery assembly. For example, the battery assembly can be installed at the required location through the metal frame.

[0134] The beneficial effects of the battery assembly of this embodiment are equivalent to the beneficial effects of the above-mentioned solar cell 100, and will not be described in detail here.

[0135] This embodiment also provides a photovoltaic system, including a battery assembly.

[0136] Photovoltaic systems can be used in photovoltaic power stations, such as ground power stations, rooftop power stations, water power stations, etc., and can also be used in equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. Of course, it is understandable that the application scenarios of photovoltaic systems are not limited to this, that is to say, photovoltaic systems can be used in all fields that require solar energy to generate electricity. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array may be an array combination of multiple battery components. For example, multiple battery components can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid. After that, it is connected to the mains network to realize solar power supply.

[0137] The beneficial effects of the photovoltaic system of this embodiment are equivalent to the beneficial effects of the above-mentioned battery assembly, and will not be described in detail here.

[0138] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A solar cell, characterized in that: include: A silicon substrate, wherein the silicon substrate has a backlight surface and a light-facing surface that are oppositely arranged, a first region and a second region are arranged on the backlight surface of the silicon substrate, the first region and the second region are arranged alternately, adjacent first regions and second regions are separated by a groove region, and a connection region is arranged between the first region and the second region to connect the first region and the second region; A first polarity doped layer stacked on the first region, wherein the first polarity doped layer has a first edge and a second edge; A second polarity doped layer is stacked on the second region and the connection region, the second polarity doped layer and the first polarity doped layer are in composite contact in the connection region, and the second polarity doped layer in the second region has a third edge; Among them, the plane where the second area is located is the first plane, the first edge and the third edge are arranged opposite to each other on both sides of the groove area, the second edge is close to the composite contact position of the second polarity doping layer and the first polarity doping layer, and the projection distance of the extension line from the second edge to the third edge on the first plane is smaller than the projection distance from the first edge to the third edge on the first plane.

2. The solar cell according to claim 1, characterized in that The third edge is flush with the edge of the second region.

3. The solar cell according to claim 1, characterized in that The third edge has a preset distance from the edge of the second area.

4. The solar cell according to claim 1, characterized in that The silicon substrate in the first region has a first notch recessed toward the first region between the first region and the groove region, the first notch has a first sidewall and a second sidewall, the first sidewall is farther away from the light-facing surface than the second sidewall, and the first sidewall and the surface of the first region have a first angle; The distances between the surfaces of the second region and the connection region and the bottom of the groove region are smaller than the distance between the surface of the first region and the bottom of the groove region; a second notch is provided between the first region and the connection region and is recessed toward the first region; the second notch has a third sidewall and a fourth sidewall; the third sidewall is further away from the light-facing surface than the fourth sidewall; and a second angle is formed between the second sidewall and the surface of the first region; The first angle is smaller than the second angle.

5. The solar cell according to claim 4, characterized in that: The second side wall and the bottom of the groove area form a first bottom edge; the fourth side wall and the surface of the connection area form a second bottom edge; the second area and the bottom of the groove area have a third bottom edge; A projection distance from the first bottom edge to the third bottom edge on the first plane is greater than a projection distance from the second bottom edge to the third bottom edge on the first plane.

6. The solar cell according to claim 1, characterized in that: At a first preset position of the groove region, along the arrangement direction of the first region and the second region, the first polarity doped layer has a first extension portion extending above the groove region, and an edge of the first extension portion is the first edge; At a second preset position of the connection region, along the arrangement direction of the first region and the second region, the first polarity doped layer has a second extension portion extending above the groove region, and an edge of the second extension portion is the second edge.

7. The solar cell according to claim 6, characterized in that The first extension portion extends longer than the second extension portion.

8. The solar cell according to claim 7, characterized in that: The first extension portion has a protruding length of 0.2 to 5 μm.

9. The solar cell according to claim 7 or 8, characterized in that: The extension length of the second extension portion is 0.1-3 μm.

10. The solar cell according to claim 6, characterized in that: The second polarity doping layer is stacked in the connection area. At the second preset position, the second polarity doping layer has a first wrapping portion. The first wrapping portion is stacked to cover the second extension portion and is in composite contact with the second extension portion.

11. The solar cell according to claim 10, characterized in that Also comprising a first dielectric layer, a second dielectric layer and a third dielectric layer; The first dielectric layer is stacked and arranged in the first region, and the first polarity doped layer is stacked and arranged on the first dielectric layer; The first extension portion has a first surface facing the groove region and a second surface facing away from the groove region; The second dielectric layer is stacked in the second region and the connection region; A third dielectric layer is disposed on at least part of the first surface, wherein the third dielectric layer has a tunneling function; The second polarity doped layer is stacked on the second dielectric layer and the third dielectric layer, and the second polarity doped layer on the third dielectric layer is connected to the second polarity doped layer on the second dielectric layer.

12. The solar cell according to claim 11, characterized in that At the second preset position, the first wrapping portion extends to cover the second dielectric layer and wraps around the end of the first extending portion and extends to cover the second surface of the first extending portion.

13. The solar cell according to claim 12, characterized in that: At the second preset position, the first wrapping portion wraps around the side walls on both sides of the end portion of the first extending portion.

14. The solar cell according to claim 12, characterized in that: An insulating layer is disposed between the first wrapping portion and the second surface.

15. The solar cell according to claim 14, characterized in that The insulating layer has a third extending portion along an extending direction of the first extending portion and protruding from the second extending portion.

16. The solar cell according to claim 12, characterized in that: The first surface and the second surface intersect at an end of the first extending portion to form a tip portion, and the first surrounding portion surrounds the tip portion.

17. The solar cell according to claim 16, characterized in that A hole is formed at the end of the tip portion.

18. The solar cell according to claim 1, characterized in that: The distance from the surface of the first polarity doped layer to the light-facing surface is H1, the distance from the surface of the second polarity doped layer in the second region to the light-facing surface is H2, and the distance from the surface of the groove region to the light-facing surface is H3, H1>H2>H3.

19. A battery assembly, characterized in that: Including the solar cell described in claims 1-18.

20. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 19.

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