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, and first areas and second areas on the backlight surface of the solar cell are alternately distributed and are connected through connecting areas. The first polarity function layer is assembled in the first area, and at a specific position of the connection area, a part of the layer extends above the connection area. The second polarity function layer group is located in the second area. The third polar functional layer group is located in the connection area, and a part of the layer forms a wrapping part, covers the extending part and extends to the first polar functional layer group. The outer edge, close to the connecting area, of the wrapping part is a first boundary line, the outer edge, away from the connecting area, of the wrapping part is a second boundary line, and the first boundary line is larger than the second boundary line in undulation. The first boundary line is large in undulation degree, the contact area between the second polarity function layer group and the first polarity function layer group can be increased, and the hot spot effect is improved. The second boundary line is small, the contact area with the first polarity function layer group is reduced, parasitic absorption is reduced, and the conversion efficiency is improved.

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 arranged opposite to each other, a first region and a second region are arranged on the backlight surface of the silicon substrate, a distance from the first region to the light-facing surface is greater than a distance from the second region to the light-facing surface, the first region and the second region are arranged alternately, and the second region extends a connection region to the first region, partially overlapping with the first region; A first polarity functional layer group stacked on the first region, wherein at a second preset position of the connection region, along the arrangement direction of the first region and the second region, at least some functional layers in the first polarity functional layer group have a protruding portion extending above the connection region; A second polarity functional layer group stacked on the second region; A third polarity functional layer group stacked in the connection region, wherein the third polarity functional layer group has the same polarity as the second polarity functional layer group and has a different polarity from the first polarity functional layer group; At the second preset position, the first polarity functional layer group and the third polarity functional layer group are in composite contact, and at least part of the functional layers in the third polarity functional layer group have a wrapping portion, which overlaps and covers the protruding portion and extends to cover the first polarity functional layer group; The edge of the wrapped portion closest to the connection area is a first boundary line, and the edge of the wrapped portion farthest from the connection area is a second boundary line. The undulation of the first boundary line is greater than that of the second boundary line.

[0006] Optionally, the adjacent first region and second region are separated by a groove region, part of the second region is connected to the first region through the connection region, the edge of the first polar functional layer group closest to the groove region is a third boundary line, and the undulation of the third boundary line is greater than that of the first boundary line.

[0007] Optionally, the first polarity functional layer group includes a first dielectric layer and a first polarity doped layer, the second polarity functional layer group includes a second dielectric layer and a second polarity doped layer, and the third polarity functional layer group includes a third dielectric layer, a fourth dielectric layer and a third polarity doped layer; The first dielectric layer is stacked on the first region, the first polarity doped layer is stacked on the first dielectric layer, and at the second preset position, along the arrangement direction of the connection region and the first region, the first polarity doped layer has a second extension portion extending above the connection region, and the second extension portion has a first surface facing the connection region and a second surface facing away from the connection region; The second dielectric layer is stacked on the second region, and the second polarity doped layer is stacked on the second dielectric layer; The third dielectric layer is stacked in the connection area, the fourth dielectric layer is arranged on at least part of the first surface, the fourth dielectric layer has a tunneling function, the third polarity doped layer is stacked on the third dielectric layer and the fourth dielectric layer, the third polarity doped layer on the third dielectric layer and the third polarity doped layer on the fourth dielectric layer are connected, and at the second preset position, the third polarity doped layer has a first wrapping portion, the first wrapping portion wraps around the end of the second extension portion and the second surface of the second extension portion and extends to the first area.

[0008] Optionally, an insulating layer is provided between the wrapping portion and the second surface.

[0009] Optionally, the insulating layer has a third extending portion protruding from the second extending portion along an arrangement direction of the connecting region and the first region.

[0010] Optionally, the first surface and the second surface intersect at an end of the second extending portion to form a tip portion, and the surrounding portion surrounds the tip portion.

[0011] Optionally, a hole is formed at the end of the tip portion.

[0012] Optionally, at a first preset position of the groove region, along an 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.

[0013] The present invention also provides a battery assembly, comprising the above-mentioned solar cell.

[0014] The present invention also provides a photovoltaic system, comprising the above-mentioned battery assembly.

[0015] 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. The first polarity functional layer group is arranged in the first area, and at a specific position of the connection area, part of the layer extends above the connection area. The second polarity functional layer group is located in the connection area and the second area, and part of the layer forms a wrapping part, covers the extended part and extends to the first polarity functional layer group. Among them, the outer edge of the wrapping part close to the connection area is the first boundary line, and the outer edge away from the connection area is the second boundary line, and the undulation of the first boundary line is greater than that of the second boundary line. The first boundary line has a large undulation, which can increase the contact area between the third polarity functional layer group and the first polarity functional layer group, improve the hot spot effect, and make the photogenerated carriers more effectively collected into the third polarity functional layer group and transmitted to the electrode, thereby improving the short-circuit current and photoelectric conversion efficiency. The second boundary line is small, which reduces the contact area with the first polarity functional layer group, reduces parasitic absorption, and improves conversion efficiency. At the same time, it can reduce the recombination of carriers at the boundary and improve the collection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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 7is 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.

[0017] 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 dielectric layer; 122, first polarity doping layer; 1221, first extension portion; 1222, second extension portion; 1222.1, first surface; 1222.2, second surface; 1222.3, tip portion; 130, second polarity functional layer group; 131, second dielectric layer; 132, second polarity doped layer; 140, insulating layer; 141, third extension portion; 150, passivation layer; 160, third polarity functional layer group; 161, third dielectric layer; 162, fourth dielectric layer; 163, third polarity doped layer; 1631, wrapping portion; 1001, first boundary line; 1002, second boundary line; 1003, third boundary line; 1004, first edge; 1005, second edge; 1006, third edge. DETAILED DESCRIPTION

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] The first area and the second area on the backlight surface of the solar cell of the present invention are alternately distributed, separated by the groove area, and connected by the connection area. The first polarity functional layer group is arranged in the first area, and at a specific position of the connection area, part of the layer extends above the connection area. The second polarity functional layer group is located in the connection area and the second area, and part of the layer forms a wrapping part, covers the extended part and extends to the first polarity functional layer group. Among them, the outer edge of the wrapping part close to the connection area is the first boundary line, and the outer edge away from the connection area is the second boundary line, and the undulation of the first boundary line is greater than that of the second boundary line. The first boundary line has a large undulation, which can increase the contact area between the third polarity functional layer group and the first polarity doped layer, improve the hot spot effect, and make the photogenerated carriers more effectively collected into the third polarity functional layer group and transmitted to the electrode, thereby improving the short-circuit current and photoelectric conversion efficiency. The second boundary line is small, which reduces the contact area with the first polarity functional layer group, reduces parasitic absorption, and improves conversion efficiency. At the same time, it can reduce the recombination of carriers at the boundary and improve the collection efficiency.

[0025] Example like Figures 1 to 9 As 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, a distance from the first region 101 to the light-facing surface is greater than a distance from the second region 102 to the light-facing surface, the first region 101 and the second region 102 are alternately arranged, and the second region 102 extends a connecting region 104 toward the first region 101, partially overlapping with the first region 101; A first polarity functional layer group 120 stacked on the first region 101, at a second preset position, 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; A second polarity functional layer group 130 stacked on the second region 102; A third polarity functional layer group 160 stacked on the connection region 104 , wherein the third polarity functional layer group 160 has the same polarity as the second polarity functional layer group 130 , and has a different polarity from the first polarity functional layer group 120 ; At the second preset position, the first polarity functional layer group 120 and the third polarity functional layer group 160 are in composite contact, and at least part of the functional layers in the third polarity functional layer group 160 have a wrapping portion, which overlaps and covers the protruding portion and extends to cover the first polarity functional layer group 120; The edge of the wrapped portion closest to the connection area 104 is a first boundary line 1001 , and the edge of the wrapped portion farthest from the connection area 104 is a second boundary line 1002 . The undulation of the first boundary line 1001 is greater than that of the second boundary line 1002 .

[0026] 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.

[0027] 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.

[0028] The distance from the first region 101 to the light-facing surface is greater than the distance from the second region 102 to the light-facing surface. That is, assuming that the light-facing surface is placed facing downward, the position of the first region 101 on the silicon substrate 110 is higher than that of the second region 102 , and there is a height difference between the first region 101 and the second region 102 .

[0029] 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.

[0030] The second area 102 extends a connection area 104 toward the first area 101, and partially overlaps with the first area 101, that is, the connection area 104 is arranged between the first area 101 and the second area 102, and covers a part of the first area 101, and plays a role of connecting the two. It can be understood that when the first area 101 and the second area 102 are arranged adjacent to each other, there is a side wall connecting the first area 101 and the second area 102, and the connection area 104 is the side wall between the first area 101 and the second area 102 and the part of the first area 101 corresponding to the side wall. When other areas are arranged between the first area 101 and the second area 102, the connection area 104 includes a first part and a second part, the first part is arranged in the other area between the first area 101 and the second area 102, and the second part is the side wall between the first part and the second area 102 and the part of the first area 101 corresponding to the side wall.

[0031] 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.

[0032] The third polarity functional layer group 160 is stacked in the connection region 104. The third polarity functional layer group 160 generally also includes a plurality of layers with different functions, such as a doping layer, a conductive layer, a tunneling layer, etc. These functional layers work together to make the third polarity functional layer group 160 exhibit polarity. The third polarity functional layer group 160 and the second polarity functional layer group 130 have the same polarity, which is different from the polarity of the first polarity functional layer group 120. The third polarity functional layer group 160 and the second polarity functional layer group 130 can be connected, that is, the third polarity functional layer group 160 and the second polarity functional layer group 130 can be an integrated structure, and each functional layer in the third polarity functional layer group 160 is integrally connected with each functional layer in the second polarity functional layer group 130 (for example, the doping layer in the third polarity functional layer group 160 is integrally connected with the doping layer in the second functional layer group 130, and the tunneling layer in the third polarity functional layer group 160 is integrally connected with the tunneling layer in the second functional layer group 130). An insulating medium may also be disposed between the third polarity functional layer group 160 and the second polarity functional layer group 130 , and the third polarity functional layer group 160 and the second polarity functional layer group 130 may be electrically connected in other ways.

[0033] Specifically, the second region 102 is stacked with the second polarity functional layer group 130, and the connection region 104 is stacked with the third polarity functional layer group 160. At the second preset position, the third polarity functional layer group 160 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 third polarity functional layer group 160 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 third polarity functional layer group 160 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 wrapped portion forms a composite contact with the first polarity functional layer group 120. Specifically, the wrapped portion may form a composite contact with the surface of the first polarity functional layer group 120 facing the connection area 104, or the wrapped portion may form a composite contact with the surface of the first polarity functional layer group 120 facing the connection area 104 and the side wall connecting the two surfaces, or the wrapped portion may form a composite contact with other positions of the first polarity functional layer group 120, which is not limited here.

[0034] It should be noted that, in this article, "composite contact" means that there is no insulation between the first polarity functional layer group 120 and the third polarity functional layer group 160, 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 third polarity functional layer group 160 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.

[0035] When a hot spot occurs, the resistance of the problematic cell increases, making it difficult for current to flow normally. The existence of the leakage channel provides an additional flow path for the current. Part of the current can bypass the problematic cell through the leakage channel, thereby avoiding a large amount of current from being concentrated in the hot spot area and reducing the heat generation power in this area.

[0036] The leakage channel can also balance the voltage between cells. In the case of hot spots, the voltage across the problematic cell will change, forming a voltage difference with other normal cells. The existence of the leakage channel allows the current to be adjusted between different cells, making the voltage of each cell more balanced. This can reduce the voltage difference between cells, further reduce the possibility of hot spots, and improve the stability and reliability of the entire solar cell 100 assembly.

[0037] It should be noted that, in the embodiments of the present application, when the first area 101 and the second area 102 are arranged adjacent to each other, the "second preset position" is placed in the second area 102, and when other areas are arranged between the first area 101 and the second area 102, the "second preset position" is placed in the connection area 104. The "second preset position" can be understood as the entire connection area 104 or the second area 102, or as a partial position of the connection area 104 or the second area 102, and is not specifically limited here. In some embodiments, the second preset position is preferably a partial position of the connection area 104 or the second area 102. In this case, in each connection area 104 or the second area 102, the number of second preset positions can be single or multiple. In a single connection area 104 or the second area 102, multiple second preset positions can be arranged at intervals along a direction perpendicular to the arrangement of the first area 101 and the second area 102, and is not specifically limited here.

[0038] like Fig. 9 As shown, 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.

[0039] The first boundary line 1001 is the outer contour of the wrapping part, and the inner contour of the wrapping part corresponds to the outer contour, and the inner contour of the wrapping part is in composite contact with the first polarity functional layer group 120. It can be understood that the thickness of the third polarity functional layer group 160 is relatively uniform, and the outer contour corresponds to the inner contour. The more rugged the outer contour is, the more rugged the inner contour is, and the smoother the outer contour is, the smoother the inner contour is.

[0040] 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 .

[0041] 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.

[0042] 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.

[0043] On the one hand, the first boundary line 1001 is the edge of the wrapping part closest to the connection area. When the first boundary line 1001 has a large undulation, it means that the boundary presents a complex, uneven shape. Since the inner contour of the wrapping part is in composite contact with the first polarity functional layer group 120, and the thickness of the third polarity functional layer group 160 is relatively uniform, the undulation of the outer contour will correspond to the inner contour. In this way, the contact area between the third polarity functional layer group 160 and the first polarity functional layer group 120 will be significantly increased. Photogenerated carriers can be more effectively collected into the third polarity functional layer group 160. This means that during the operation of the battery, the charge can be conducted more smoothly, reducing the problem of local overheating caused by charge accumulation and improving the hot spot effect.

[0044] On the other hand, when the undulation of the second boundary line 1002 is small, the contact area between the third polarity functional layer group 160 and the first polarity functional layer group 120 is reduced. This means that the contact areas that may cause parasitic absorption inside the battery are reduced. At some unnecessary contact interfaces, light scattering, reflection or other ineffective absorption processes may occur. Reducing the contact area can reduce the probability of these parasitic absorption phenomena, so that more light energy can be used to generate photogenerated carriers, thereby improving conversion efficiency.

[0045] Specifically, during observation, it can be a top view of a magnified view of a solar cell microscope. Since the first boundary line 1001 and the second boundary line 1002 are both outer contours of the third polarity functional layer group 160, the first boundary line 1001 and the second boundary line 1002 of the solar cell form obvious contour lines on the cell, such as Fig. 9 As shown, the contour lines formed in the top view are the first boundary line 1001 and the second boundary line 1002 .

[0046] In this embodiment, the first region 101 and the second region 102 are alternately distributed on the backlight surface of the solar cell 100 and connected by the connection region 104. The first polarity functional layer group 120 is provided in the first region 101, and has an extended portion that partially extends out of the first region 101 at a specific position. The third polarity functional layer group 160 is provided in the connection region 104, and partially forms a wrapping portion, covers the extended portion and extends to the first polarity functional layer group 120. Among them, the outer edge of the wrapping portion close to the connection region 104 is the first boundary line 1001, and the outer edge away from the connection region 104 is the second boundary line 1002, and the undulation of the first boundary line 1001 is greater than that of the second boundary line 1002. The first boundary line 1001 has a large undulation, which can increase the contact area between the third polarity functional layer group 160 and the first polarity doping layer 122, improve the hot spot effect, and make the photogenerated carriers more effectively collected into the third polarity functional layer group 160 and transmitted to the electrode, thereby improving the short-circuit current and photoelectric conversion efficiency. The second boundary line 1002 is small, which reduces the contact area with the first polarity functional layer group 120, reduces parasitic absorption, and improves conversion efficiency. At the same time, it can reduce carrier recombination at the boundary and improve collection efficiency.

[0047] like Fig. 9 As shown, in some embodiments, the adjacent first region 101 and second region 102 are separated by a groove region 103, a portion of the second region 102 is connected to the first region 101 via a connecting region 104, and the edge of the first polarity functional layer group 120 closest to the groove region 103 is the third boundary line 1003, and the undulation of the third boundary line 1003 is greater than the undulation of the first boundary line 1001.

[0048] 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.

[0049] A groove region 103 is provided between the adjacent first region 101 and the second region 102, for isolating the first region 101 from 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, which is placed 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 provided in the connection region 104, and the first region 101 and the second region 102 are connected.

[0050] The third boundary line 1003 is the edge of the first layer group on one side facing the groove region 103 . When the solar cell 100 is viewed from above, the boundary between the first layer group and the groove region 103 is the third boundary line 1003 .

[0051] The main function of the groove area 103 is to isolate the first area 101 and the second area 102 to prevent unnecessary current leakage between them. The larger undulation of the third boundary line 1003 means that its contact boundary with the groove area 103 is more complex and tortuous. This increases the difficulty of the current flowing from the first polarity functional layer group 120 across the groove area 103 to the second area 102, which is equivalent to extending the leakage path. When the current passes through such a complex boundary, it will encounter more obstacles, thereby effectively reducing the possibility of leakage and improving the electrical isolation performance of the battery.

[0052] like Figures 5 to 7 As shown, in some embodiments, the first polarity functional layer group 120 includes a first dielectric layer 121 and a first polarity doped layer 122, the second polarity functional layer group 130 includes a second dielectric layer 131 and a second polarity doped layer 132, and the third polarity functional layer group 160 includes a third dielectric layer 161, a fourth dielectric layer 162 and a third polarity doped layer 163; 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. At a 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. The second dielectric layer 131 is stacked on the second region 102 , and the second polarity doped layer 132 is stacked on the second dielectric layer 131 ; The third dielectric layer 161 is stacked on the connection area 104, and the fourth dielectric layer 162 is arranged on at least part of the first surface 1222.1. The fourth dielectric layer 162 has a tunneling function. The third polarity doped layer 163 is stacked on the third dielectric layer 161 and the fourth dielectric layer 162. The third polarity doped layer 163 on the third dielectric layer 161 and the third polarity doped layer 163 on the fourth dielectric layer 162 are connected. At the second preset position, the third polarity doped layer 163 has a first wrapping portion 1631. The first wrapping portion 1631 wraps around the end of the second extension portion 1222 and the second surface 1222.2 of the second extension portion 1222 and extends to the first area 101.

[0053] The first polarity functional layer group 120 includes a first dielectric layer 121 and a first polarity doped layer 122. 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. The specific type may be selected according to actual conditions and is not specifically limited here.

[0054] 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. In this embodiment, at least part of the functional layers in the first polarity functional layer group 120 have an extension portion extending above the connection region 104, that is, the first polarity doped layer 122 in the first polarity functional layer group 120 has a first extension portion extending above the connection region 104.

[0055] The second polarity functional layer group 130 includes a second dielectric layer 131 and a second polarity doping layer 132 . The second dielectric layer 131 is stacked in the second region 102 , and the second polarity doping layer 132 is stacked on the second dielectric layer 131 .

[0056] The third dielectric layer 161 is stacked on the connection area 104, and the fourth dielectric layer 162 is arranged on at least part of the first surface 1222.1, that is, the fourth dielectric layer 162 covers all or part of the first surface 1222.1. The third dielectric layer 161 is stacked on the connection area 104, that is, when the first area 101 and the second area 102 are arranged adjacent to each other, the third dielectric layer 161 is stacked on the side wall between the first area 101 and the second area 102; when there are other areas (such as the groove area 103) between the first area 101 and the second area 102, the third dielectric layer 161 can be arranged only on the bottom surface of the connection area 104, or it can be arranged on the bottom surface of the connection area 104 and extend to the side wall between the connection area 104 and the first area 101. Specifically, the third dielectric layer 161 on the side wall between the connection area 104 and the first area 101 can be connected or disconnected with the fourth dielectric layer 162, which is not limited here. The fourth dielectric layer 162 has a tunneling function. The fourth dielectric layer 162 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.

[0057] The second polarity doped layer 132 is stacked on the third dielectric layer 161 and the fourth dielectric layer 162, and the second polarity doped layer 132 on the third dielectric layer 161 and the second polarity doped layer 132 on the fourth dielectric layer 162 are connected, that is, regardless of whether the second dielectric layer 131 and the third dielectric layer 161 are connected or not, the second polarity doped layer 132 stacked on the second dielectric layer 131 and the third dielectric layer 161 is not interrupted. Specifically, the second polarity doped layer 132 may be in direct contact with the third dielectric layer 161 and the fourth dielectric layer 162, or other functional layers may be disposed between the second polarity doped layer 132 and the third dielectric layer 161 and the fourth dielectric layer 162, which is not limited here. The second polarity doping layer 132 has a first wrapping portion 1631 , which wraps around an end of the second extension portion 1222 and a second surface 1222 . 2 of the second extension portion 1222 and extends to the first region 101 .

[0058] Specifically, at the second preset position of the connection area 104, the first wrapping portion 1631 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 1631 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 1631 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.

[0059] In this embodiment, the outer contour of the second polarity doping layer 132 surrounding the first protruding portion may be a first boundary line 1001 , and the edge of the second polarity doping layer 132 extending to the first region 101 may be a second boundary line 1002 .

[0060] 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.

[0061] 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 surface of the silicon substrate 110 in the first region 101 is The surface of the silicon substrate 110 has a height difference with the surface of the other regions (the connection region 104, the second region 102 and the groove region 103), and the second extension portion 1222 of the first polarity doped layer 122 at the second preset position extends above the connection region 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 the second extension portion 1222 extending above the connection region 104.

[0062] 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 second extension portion 1222. 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 1631 at a second preset position, and the first wrapping portion 1631 wraps around the end of the second extension portion 1222 and the second surface 1222.2 of the second extension portion 1222 and extends to the first region 101.

[0063] 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.

[0064] like Figure 2 As shown, in some embodiments, 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 a third polarity doping layer 163 is stacked on the connection region 104. The third polarity doping layer 163 and the first polarity doping layer 122 are in composite contact in the connection region 104. The second polarity doping layer 132 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.

[0065] The first polarity doped layer 122 is stacked on the first region 101. 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. The second edge 1005 may be specifically an edge of the second extension portion 1222 close to the connection region.

[0066] 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 has a third edge 1006, which 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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 third polarity doping layer 163 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.

[0074] like Figure 1 As shown, in some embodiments, the third edge 1006 is flush with the edge of the second region 102 .

[0075] 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 .

[0076] 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.

[0077] This structural design can improve the compactness and regularity of the internal structure of the battery, facilitate the uniform conduction of current, reduce resistance loss, and thus improve the photoelectric conversion efficiency of the battery.

[0078] 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 .

[0079] 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 .

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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 .

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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 wrapping portion extends to cover the first polarity doping layer 122 on the protruding portion and covers a portion 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 wrapping portion, 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.

[0096] like Figure 4 As shown, in some embodiments, at the second preset position, the first wrapping portion 1631 wraps around the side walls on both sides of the end portion of the second extension portion 1222 .

[0097] The second extension portion 1222 has two opposite side walls, and the first wrapping portion 1631 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 portions are all wrapped by the first wrapping portion 1631 .

[0098] The first wrapping portion 1631 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.

[0099] In some embodiments, an insulating layer 140 is disposed between the wraparound portion and the second surface 1222 . 2 .

[0100] The wrapping portion is a portion 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 wrapping portion 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.

[0101] In this embodiment, the provision of the insulating layer 140 prevents the unnecessary flow of electrons between the wrapping portion and the second extension portion 1222, 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, and further improving the photoelectric conversion efficiency of the battery.

[0102] 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 .

[0103] The insulating layer 140 is not only arranged between the wrapping portion 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.

[0104] 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.

[0105] 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.

[0106] 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 second extension 1222 to form a tip portion 1222.3, and the wrapping portion wraps around the tip portion 1222.3.

[0107] The end of the second extension portion 1222 is pointed. Even if the first wrapping portion 1631 wraps around the tip portion 1222.3, there is only line-surface contact between the first wrapping portion 1631 and the tip of the tip portion 1222.3, which can reduce the contact area between the end of the second extension portion 1222 and the first wrapping portion 1631 and reduce the composite.

[0108] Of course, it can be understood that in some embodiments, the end of the second extension portion 1222 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 1631 may wrap around the end face of the second extension portion 1222. When the first wrapping portion 1631 wraps around the end face of the second extension portion 1222, a dielectric layer may or may not be provided between the end face and the first wrapping portion 1631. 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.

[0109] In some embodiments, a hole is formed at the end of the tip portion 1222.3.

[0110] 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 1631 and the end of the tip portion 1222.3, thereby reducing the composite.

[0111] 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.

[0112] 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 .

[0113] 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.

[0114] The second polarity doping layer 132 is closer to the light-facing surface than the first polarity doping layer 122 (H2

[0115] This embodiment provides a battery assembly including a plurality of solar cells 100 .

[0116] 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.

[0117] 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.

[0118] ​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.

[0119] 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.

[0120] 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.

[0121] This embodiment also provides a photovoltaic system, including a battery assembly.

[0122] 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.

[0123] 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.

[0124] 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 arranged opposite to each other, a first region and a second region are arranged on the backlight surface of the silicon substrate, a distance from the first region to the light-facing surface is greater than a distance from the second region to the light-facing surface, the first region and the second region are arranged alternately, and the second region extends a connection region to the first region, partially overlapping with the first region; A first polarity functional layer group stacked on the first region, wherein at a second preset position, along the arrangement direction of the first region and the second region, at least part of the functional layers in the first polarity functional layer group have a protruding portion extending above the connection region; A second polarity functional layer group stacked on the second region; A third polarity functional layer group stacked on the connection region, wherein the third polarity functional layer group has the same polarity as the second polarity functional layer group and has a different polarity from the first polarity functional layer group; At the second preset position, the first polarity functional layer group and the third polarity functional layer group are in composite contact, and at least part of the functional layers in the third polarity functional layer group have a wrapping portion, which overlaps and covers the protruding portion and extends to cover the first polarity functional layer group; The edge of the wrapped portion closest to the connection area is a first boundary line, the edge of the wrapped portion farthest from the connection area is a second boundary line, and the undulation of the first boundary line is greater than that of the second boundary line.

2. The solar cell according to claim 1, characterized in that The adjacent first region and second region are separated by a groove region, part of the second region is connected to the first region through the connection region, the edge of the first polarity functional layer group closest to the groove region is a third boundary line, and the undulation of the third boundary line is greater than that of the first boundary line.

3. The solar cell according to claim 1, characterized in that The first polarity functional layer group includes a first dielectric layer and a first polarity doped layer, the second polarity functional layer group includes a second dielectric layer and a second polarity doped layer, and the third polarity functional layer group includes a third dielectric layer, a fourth dielectric layer and a third polarity doped layer; The first dielectric layer is stacked on the first region, the first polarity doped layer is stacked on the first dielectric layer, and at the second preset position, along the arrangement direction of the connection region and the first region, the first polarity doped layer has a second extension portion extending above the connection region, and the second extension portion has a first surface facing the connection region and a second surface facing away from the connection region; The second dielectric layer is stacked on the second region, and the second polarity doped layer is stacked on the second dielectric layer; The third dielectric layer is stacked in the connection area, the fourth dielectric layer is arranged on at least part of the first surface, the fourth dielectric layer has a tunneling function, the third polarity doped layer is stacked on the third dielectric layer and the fourth dielectric layer, the second polarity doped layer on the third dielectric layer and the second polarity doped layer on the fourth dielectric layer are connected, and at the second preset position, the third polarity doped layer has a first wrapping portion, the first wrapping portion wraps around the end of the second extension portion and the second surface of the second extension portion and extends to the first area.

4. The solar cell according to claim 3, characterized in that: An insulating layer is disposed between the wrapping portion and the second surface.

5. The solar cell according to claim 4, characterized in that: The insulating layer has a third extending portion protruding from the second extending portion along an arrangement direction of the connecting region and the first region.

6. The solar cell according to claim 3, characterized in that: The first surface and the second surface intersect at an end of the second extension portion to form a tip portion, and the surrounding portion surrounds the tip portion.

7. The solar cell according to claim 6, characterized in that A hole is formed at the end of the tip portion.

8. The solar cell according to claim 2, characterized in that: At a first preset position of the groove region, along an 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.

9. A battery assembly, characterized in that: The invention comprises a plurality of solar cells according to claims 1 to 8.

10. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 9.

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