A solar cell, a battery module and a photovoltaic system

Abstract

The present invention is applicable to the field of photovoltaic technology, and provides a solar cell, a battery module and a photovoltaic system. On the backlight surface of the solar cell, a first region and a second region are alternately distributed and connected by a connection region. A first-polarity functional layer is disposed in the first region, and at a specific position in the connection region, a part of the layer extends above the connection region. A second-polarity functional layer is located in the second region. A third-polarity functional layer is located in the connection region, and a part of the layer forms a surrounding part that covers the extending part and extends to the first-polarity functional layer. The outer edge of the surrounding part close to the connection region is the first boundary line, and the outer edge far from the connection region is the second boundary line, and the undulation degree of the first boundary line is greater than that of the second boundary line. The large undulation degree of the first boundary line can increase the contact area between the second-polarity functional layer and the first-polarity functional layer, and improve the hot spot effect. The small second boundary line reduces the contact area with the first-polarity functional layer, reduces parasitic absorption, and improves the conversion efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaics, and particularly relates to a solar cell, a battery module 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. A solar cell is the core device that directly converts solar energy into electrical energy and is a key technology for the efficient utilization of solar energy. The photoelectric conversion efficiency refers to the proportion of incident light energy converted into electrical energy by a solar cell and is the core index for measuring the performance of a solar cell. Improving the photoelectric conversion efficiency can increase the electrical energy output per unit area and reduce the power generation cost.

[0003] Currently, 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 electrical energy output per unit area, reduce the power generation cost, thereby shortening the investment recovery period, enhancing market competitiveness, and promoting 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 also is the key to promoting the sustainable development of the photovoltaic industry. Summary of the Invention

[0004] The present invention provides a solar cell, a battery module 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 implemented as follows. A solar cell includes:

[0006] A silicon substrate having a backlight surface and a light-facing surface disposed opposite to each other. A first region and a second region are provided on the backlight surface of the silicon substrate. The distance from the first region to the light-facing surface is greater than the distance from the second region to the light-facing surface. The first region and the second region are alternately arranged, and the second region extends a connection region towards the first region and partially overlaps with the first region;

[0007] A first-polarity functional layer group stacked on the first region. At a second preset position of the connection region, along the arrangement direction of the first region and the second region, at least some of the functional layers in the first-polarity functional layer group have an extending portion extending above the connection region;

[0008] A second-polarity functional layer group stacked on the second region;

[0009] A third polar functional layer group stacked within the connection region, the third polar functional layer group having the same polarity as the second polar functional layer group and a different polarity from the first polar functional layer group;

[0010] At the second preset position, the first polar functional layer group and the third polar functional layer group are in composite contact. At least some of the functional layers in the third polar functional layer group have a wrapping portion that layer-by-layer covers the protruding portion and extends to cover the first polar functional layer group;

[0011] The edge of the wrapping portion closest to the connection region is the first boundary line, and the edge of the wrapping portion farthest from the connection region is the second boundary line. The undulation degree of the first boundary line is greater than that of the second boundary line.

[0012] Optionally, the adjacent first region and the second region are separated by a trench region, and 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 trench region is the third boundary line, and the undulation degree of the third boundary line is greater than that of the first boundary line.

[0013] Optionally, the first polar functional layer group includes a first dielectric layer and a first polar doping layer, the second polar functional layer group includes a second dielectric layer and a second polar doping layer, and the third polar functional layer group includes a third dielectric layer, a fourth dielectric layer, and a third polar doping layer;

[0014] The first dielectric layer is stacked on the first region, and the first polar doping layer is stacked on the first dielectric layer. At the second preset position, along the arrangement direction of the connection region and the first region, the first polar doping layer has a second extension portion extending above the connection region. The second extension portion has a first surface facing the connection region and a second surface facing away from the connection region;

[0015] The second dielectric layer is stacked on the second region, and the second polar doping layer is stacked on the second dielectric layer;

[0016] The third dielectric layer is stacked on the connection region. The fourth dielectric layer is disposed on at least part of the first surface. The fourth dielectric layer has a tunneling function. The third polar doping layer is stacked on the third dielectric layer and the fourth dielectric layer. The third polar doping layer on the third dielectric layer and the third polar doping layer on the fourth dielectric layer are connected. At the second preset position, the third polar doping layer has a first wrapping portion that wraps the end of the second extension portion and the second surface of the second extension portion and extends to the first region.

[0017] Optionally, an insulating layer is provided between the wrapping portion and the second surface.

[0018] Optionally, the insulating layer has a third extension portion protruding from the second extension portion along the arrangement direction of the connection region and the first region.

[0019] Optionally, the first surface and the second surface intersect at the end of the second extension portion to form a pointed end portion, and the wrapping portion wraps the pointed end portion.

[0020] Optionally, a hole is formed at the end of the pointed end portion.

[0021] Optionally, at a first preset position in the trench region, along the arrangement direction of the first region and the second region, the first polar doping layer has a first extension portion extending above the trench region.

[0022] The present invention also provides a battery assembly, including the above-mentioned solar cell.

[0023] The present invention also provides a photovoltaic system, including the above-mentioned battery assembly.

[0024] The beneficial effects achieved by the present invention are as follows: Since the first region and the second region are alternately distributed on the backlight surface of the solar cell, separated by the trench region and connected by the connection region. The first polar functional layer group is disposed in the first region, and at a specific position in the connection region, part of the layer extends above the connection region. The second polar functional layer group is located in the connection region and the second region, and part of the layer forms a wrapping portion that covers the extending portion and extends to the first polar functional layer group. Among them, the outer edge of the wrapping portion close to the connection region is the first boundary line, and the outer edge far from the connection region is the second boundary line, and the undulation degree of the first boundary line is greater than that of the second boundary line. The large undulation degree of the first boundary line can increase the contact area between the third polar functional layer group and the first polar functional layer group, improve the hot spot effect, enable the photo-generated carriers to be more effectively collected into the third polar functional layer group and transmitted to the electrode, and improve the short-circuit current and the photoelectric conversion efficiency. The small second boundary line reduces the contact area with the first polar functional layer group, reduces parasitic absorption, and improves the conversion efficiency. At the same time, the recombination of carriers at the boundary can be reduced, and the collection efficiency can be improved. Description of the Drawings

[0025] Figure 1 is the first structural schematic diagram of the solar cell provided by the present invention;

[0026] Figure 2 is the second structural schematic diagram of the solar cell provided by the present invention;

[0027] Figure 3It is the third structural schematic diagram of the solar cell provided by the present invention;

[0028] Figure 4 It is the fourth structural schematic diagram of the solar cell provided by the present invention;

[0029] Figure 5 It is a schematic cross-sectional structure diagram of the solar cell provided by the present invention;

[0030] Figure 6 It is an enlarged view at position A;

[0031] Figure 7 It is another schematic cross-sectional structure diagram of the solar cell provided by the present invention;

[0032] Figure 8 It is a schematic structural diagram of the silicon substrate provided by the present invention;

[0033] Figure 9 It is a magnified top view of the solar cell provided by the present invention under a microscope.

[0034] Description of reference numerals:

[0035] 100, solar cell; 110, silicon substrate; 101, first region; 102, second region; 103, trench 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 polar functional layer group; 121, first dielectric layer; 122, first polar doped layer; 1221, first extension; 1222, second extension; 1222.1, first surface; 1222.2, second surface; 1222.3, tip; 130, second polar functional layer group; 131, second dielectric layer; 132, second polar doped layer; 140, insulating layer; 141, third extension; 150, passivation layer; 160, third polar functional layer group; 161, third dielectric layer; 162, fourth dielectric layer; 163, third polar doped layer; 1631, wrapping part;

[0036] 1001, first boundary line; 1002, second boundary line; 1003, third boundary line; 1004, first edge, 1005, second edge; 1006, third edge. Detailed implementation manners

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention, and should not be construed as a limitation to 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 used to limit the present invention.

[0038] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is 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 thus should not be construed as a limitation to the present invention.

[0039] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0040] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection, an electrical connection or a connection capable of mutual communication; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0042] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art can realize the application of other processes and / or the use of other materials.

[0043] On the backlight surface of the solar cell of the present invention, the first region and the second region are alternately distributed, separated by a trench region, and connected by a connection region. The first-polarity functional layer group is disposed in the first region. At a specific position in the connection region, part of the layer extends above the connection region. The second-polarity functional layer group is located in the connection region and the second region. Part of the layer forms a wrapping part that covers the extending part and extends to the first-polarity functional layer group. Among them, the outer edge of the wrapping part close to the connection region is the first boundary line, and the outer edge far from the connection region is the second boundary line, and the undulation degree of the first boundary line is greater than that of the second boundary line. The large undulation degree of the first boundary line can increase the contact area between the third-polarity functional layer group and the first-polarity doping layer, improve the hot spot effect, enable the photo-generated carriers to be more effectively collected into the third-polarity functional layer group and transmitted to the electrode, and improve the short-circuit current and the photoelectric conversion efficiency. The small second boundary line reduces the contact area with the first-polarity functional layer group, reduces parasitic absorption, and improves the conversion efficiency. At the same time, the recombination of carriers at the boundary can be reduced, and the collection efficiency can be improved.

[0044] Embodiment

[0045] As Figures 1 to 9 shown, this embodiment provides a solar cell 100, including:

[0046] A silicon substrate 110, the silicon substrate 110 has a backlight surface and a light-facing surface arranged oppositely. A first region 101 and a second region 102 are provided on the backlight surface of the silicon substrate 110. 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. The first region 101 and the second region 102 are alternately arranged. The second region 102 extends out a connection region 104 to the first region 101 and partially overlaps with the first region 101;

[0047] 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 extending parts that extend above the connection region 104;

[0048] The second-polarity functional layer group 130 stacked on the second region 102;

[0049] The third-polarity functional layer group 160 stacked on the connection region 104, the third-polarity functional layer group 160 has the same polarity as the second-polarity functional layer group 130, and the third-polarity functional layer group 160 has a different polarity from the first-polarity functional layer group 120;

[0050] At the second preset position, the first-polarity functional layer group 120 and the third-polarity functional layer group 160 are in composite contact. At least some of the functional layers in the third-polarity functional layer group 160 have a wrapping portion, and the wrapping portion is stacked and covers the protruding portion, and extends to cover the first-polarity functional layer group 120;

[0051] The edge of the wrapping portion closest to the connection region 104 is the first boundary line 1001, and the edge of the wrapping portion farthest from the connection region 104 is the second boundary line 1002. The undulation degree of the first boundary line 1001 is greater than the undulation degree of the second boundary line 1002.

[0052] The silicon substrate 110 has two main surfaces, a light-facing surface and a backlight-facing surface. The light-facing surface directly faces the sun, and the backlight-facing surface is on the other side. The two surfaces are arranged opposite to each other.

[0053] Two different regions, a first region 101 and a second region 102, are arranged on the backlight-facing surface of the silicon substrate 110, and these two regions are arranged alternately. Specifically, a plurality of first regions 101 and a plurality of second regions 102 are arranged alternately along a first direction, and both the first region 101 and the second region 102 extend along a second direction, and the second direction intersects the first direction. The first region 101 and the second region 102 can be arranged alternately along the lateral direction of the silicon substrate 110 and both extend along the longitudinal direction, that is, the first direction can be the lateral direction of the back-contact battery, and the second direction can 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 can also be other directions. For example, the two can be the diagonal directions of the silicon substrate 110 respectively, and specific details are not limited here. The first region 101 and the second region 102 do not overlap with each other, and the first region 101 and the second region 102 are adjacent to each other.

[0054] 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 the light-facing surface is placed downward, the position of the first region 101 on the silicon substrate 110 is higher than the position of the second region 102, and there is a height difference between the first region 101 and the second region 102.

[0055] A first polar functional layer group 120 is disposed within the first region 101. The first polar functional layer group 120 typically includes multiple layers with different functions. For example, there may be a doping layer, a conductive layer, a tunneling layer, etc. These functional layers work together to make the first polar functional layer group 120 exhibit polarity. A second polar functional layer group 130 is disposed within the second region 102. The second polar functional layer group 130 also typically includes multiple layers with different functions. For example, there may be a doping layer, a conductive layer, a tunneling layer, etc. These functional layers work together to make the second polar functional layer group 130 exhibit polarity. The polarities of the first polar functional layer group 120 and the second polar functional layer group 130 are different. Specifically, the first polar functional layer group 120 can be a P-type functional layer group and the second polar functional layer group 130 can be an N-type functional layer group, or the first polar functional layer group 120 can be an N-type functional layer group and the second polar functional layer group 130 can be a P-type functional layer group. The first polar functional layer group 120 and the second polar functional layer group 130 form regions with different electrical characteristics, supporting the formation of a PN junction and the separation of carriers.

[0056] The second region 102 extends a connection region 104 towards the first region 101, which partially overlaps with the first region 101. That is, the connection region 104 is disposed between the first region 101 and the second region 102 and covers a part of the first region 101, serving to connect the two. It can be understood that when the first region 101 and the second region 102 are adjacent, there is a side wall connecting the two between the first region 101 and the second region 102. The connection region 104 is the side wall between the first region 101 and the second region 102 and the corresponding part of the first region 101. When there are other regions between the first region 101 and the second region 102, the connection region 104 includes a first part and a second part. The first part is disposed within the other region between the first region 101 and the second region 102, and the second part is the side wall between the first part and the second region 102 and the corresponding part of the first region 101.

[0057] At a second preset position of the connection region 104, along the arrangement direction of the first region 101 and the second region 102, at least some of the functional layers in the first polar functional layer group 120 have an extending part that extends above the connection region 104. One or more functional layers in the first polar functional layer group 120 have an extending part, and the extending part is placed above the connection region 104. It can be understood that the first polar functional layer group 120 is disposed on the surface of the first region 101, and the extending part 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.

[0058] The third-polarity functional layer group 160 is stacked inside the connection region 104. The third-polarity functional layer group 160 usually also includes multiple layers with different functions. For example, there may be 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 has the same polarity as the second-polarity functional layer group 130 and a different polarity from 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 integral structure, and each functional layer in the third-polarity functional layer group 160 is integrally connected to the corresponding 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 to 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 to the tunneling layer in the second functional layer group 130). An insulating medium can also be provided 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 are electrically connected in other ways.

[0059] Specifically, the second-polarity functional layer group 130 is stacked in the second region 102, and the third-polarity functional layer group 160 is stacked in the connection region 104. At the second preset position, the third-polarity functional layer group 160 has a wrapping part that is stacked and covers the protruding part of the first-polarity functional layer group 120 and extends to cover the first-polarity functional layer group 120. The protruding part 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 is stacked on the protruding part, that is, the third-polarity functional layer group 160 is wrapped and stacked on the surface of the protruding part 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 part forms a composite contact with the first-polarity functional layer group 120. Specifically, the wrapping part can form a composite contact with the surface of the first-polarity functional layer group 120 facing the connection region 104, or the wrapping part can form a composite contact with the surface of the first-polarity functional layer group 120 facing the connection region 104 and the side wall connecting the two surfaces, or the wrapping part can form a composite contact with other positions of the first-polarity functional layer group 120, which is not limited here.

[0060] It should be noted that in this text, "compound contact" means that there is no insulation between the first polar functional layer group 120 and the third polar functional layer group 160, but leakage conduction forms a leakage channel. Specifically, it can be that the doped layers in the first polar functional layer group 120 and the doped layers in the third polar functional layer group 160 are in direct contact to form a leakage channel, or tunneling can be achieved through other dielectric layers to achieve the function of compound contact, which is not specifically limited here.

[0061] When a hot spot occurs, the resistance of the problematic cell increases, and it is difficult for current to pass through normally. The existence of the leakage channel provides an additional current flow path. Part of the current can bypass the problematic cell through the leakage channel, thus avoiding a large amount of current concentrating in the hot spot area and reducing the heating power of this area.

[0062] The leakage channel can also play a role in balancing the voltage between cells. In the case of a hot spot, the voltage across the problematic cell changes, forming a voltage difference with other normal cells. The existence of the leakage channel enables the current to be adjusted between different cells, making the voltages of each cell more balanced. This can reduce the voltage difference between cells, further reduce the possibility of hot spot generation, and improve the stability and reliability of the entire solar cell 100 module.

[0063] It should be noted that in the embodiments of this application, when the first region 101 and the second region 102 are adjacent, the "second preset position" is located within the second region 102. When there are other regions between the first region 101 and the second region 102, the "second preset position" is located within the connection region 104. The "second preset position" can be understood as the entire connection region 104 or the second region 102, or it can be understood as a partial position of the connection region 104 or the second region 102, which is not specifically limited here. In some embodiments, the second preset position is preferably a partial position of the connection region 104 or the second region 102. In such a case, in each connection region 104 or second region 102, the number of second preset positions can be single or multiple. In a single connection region 104 or second region 102, multiple second preset positions can be arranged at intervals along the direction perpendicular to the arrangement direction of the first region 101 and the second region 102, which is not specifically limited here.

[0064] As Figure 9 shown, the edge of the wrapping part closest to the connection region 104 is the first boundary line 1001. The wrapping part wraps and overlays on the protruding part. That is, the wrapping layer overlays on the surface of the protruding part facing the connection region 104, the surface facing away from the connection region 104, and the side walls connecting the two surfaces. The outer contour of the wrapping part overlaying on the side walls connecting the two surfaces (the contour facing away from this side wall) is the first boundary line 1001.

[0065] The first boundary line 1001 is the outer contour of the wrapped part. Corresponding to the outer contour is the inner contour of the wrapped part, and the inner contour of the wrapped part is in composite contact with the first polar functional layer group 120. It can be understood that the thickness of the third polar functional layer group 160 is relatively uniform. If the outer contour corresponds to the inner contour, the more rugged the outer contour, the more rugged the inner contour, and the flatter the outer contour, the flatter the inner contour.

[0066] The edge of the wrapped part farthest from the connection area 104 is the second boundary line 1002. The wrapped part extends and covers the first polar functional layer group 120, and the edge extending towards the first area 101 and away from the connection area 104 is the second boundary line 1002.

[0067] The undulation degree of the first boundary line 1001 is greater than that of the second boundary line 1002. The undulation degree is an index used to describe the irregularity or fluctuation of an object's edge. In the context of the structure of this solar cell 100, the undulation degree is specifically used to measure the irregular shape characteristics of the first boundary line 1001 and the second boundary line 1002 of the wrapped part.

[0068] For the edge of the wrapped part, it is not an absolutely smooth and straight line, but there are high and low, tortuous changes. The greater the undulation degree, the more obvious these high and low, tortuous changes of the edge are, the more irregular and fluctuating the line is; the smaller the undulation degree, the smoother the edge is and the closer it is to a straight line state.

[0069] On the one hand, the first boundary line 1001 is the edge of the wrapped part closest to the connection area. When the undulation degree of the first boundary line 1001 is large, it means that this boundary presents a complex and uneven shape. Since the inner contour of the wrapped part is in composite contact with the first polar functional layer group 120, and the thickness of the third polar 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 polar functional layer group 160 and the first polar functional layer group 120 will increase significantly. Photo-generated carriers can be more effectively collected into the third polar functional layer group 160. This means that during the operation of the battery, charges can be conducted more smoothly, reducing the problem of local overheating caused by charge accumulation and improving the hot spot effect.

[0070] On the other hand, when the undulation degree of the second boundary line 1002 is small, the contact area between the third polar functional layer group 160 and the first polar functional layer group 120 decreases. This means that inside the battery, the contact areas that may cause parasitic absorption become smaller. At some unnecessary contact interfaces, light scattering, reflection or other non-effective absorption processes may occur. Reducing the contact area can reduce the occurrence probability of these parasitic absorption phenomena, enabling more light energy to be used to generate photo-generated carriers, thereby improving the conversion efficiency.

[0071] Specifically, during observation, it can be a top view of the magnified view of the solar cell microscope. Since both the first boundary line 1001 and the second boundary line 1002 are the 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, as Figure 9 shown, the contour lines formed on the top view are the first boundary line 1001 and the second boundary line 1002.

[0072] 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 are connected by the connection region 104. The first-polarity functional layer group 120 is disposed in the first region 101 and has an extended portion that extends out of the first region 101 at a specific position. The third-polarity functional layer group 160 is disposed in the connection region 104, and part of it forms a surrounding portion that covers the extended portion and extends to the first-polarity functional layer group 120. Among them, the outer edge of the surrounding portion close to the connection region 104 is the first boundary line 1001, and the outer edge far from the connection region 104 is the second boundary line 1002, and the undulation degree of the first boundary line 1001 is greater than that of the second boundary line 1002. The large undulation degree of the first boundary line 1001 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, enable the photo-generated carriers to be more effectively collected into the third-polarity functional layer group 160 and transmitted to the electrode, and improve the short-circuit current and the photoelectric conversion efficiency. The small second boundary line 1002 reduces the contact area with the first-polarity functional layer group 120, reduces parasitic absorption, and improves the conversion efficiency. At the same time, the recombination of carriers at the boundary can be reduced, and the collection efficiency can be improved.

[0073] As Figure 9 shown, in some embodiments, the adjacent first region 101 and second region 102 are separated by the trench region 103, and part of the second region 102 is connected to the first region 101 through the connection region 104. The edge of the first-polarity functional layer group 120 closest to the trench region 103 is the third boundary line 1003, and the undulation degree of the third boundary line 1003 is greater than that of the first boundary line 1001.

[0074] The trench region 103 is provided between the first region 101 and the second region 102. The trench region 103 is the region where the trench is provided. The trench region 103 is in a concave state compared to the surfaces of the first region 101 and the second region 102, and spatially separates the first region 101 and the second region 102 to achieve electrical isolation between the first region 101 and the second region 102 and avoid current interference between the adjacent first region 101 and second region 102.

[0075] A groove region 103 is provided between the adjacent first region 101 and second region 102 to isolate the first region 101 and the second region 102. The connection region 104 is a part of the second region 102 extending towards the first region 101, that is, the second region 102 extends towards the first region 101 to form the connection region 104, which is disposed 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.

[0076] The third boundary line 1003 is the edge of the first layer group facing the groove region 103. When looking down at the solar cell 100, the boundary between the first layer group and the groove region 103 is the third boundary line 1003.

[0077] The main function of the groove region 103 is to isolate the first region 101 and the second region 102 and prevent unnecessary current leakage between them. The relatively large undulation of the third boundary line 1003 means that its contact boundary with the groove region 103 is more complex and tortuous. This increases the difficulty for current to flow from the first polar functional layer group 120 across the groove region 103 to the second region 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.

[0078] As Figures 5 to 7 shown, in some embodiments, the first polar functional layer group 120 includes a first dielectric layer 121 and a first polar doped layer 122, the second polar functional layer group 130 includes a second dielectric layer 131 and a second polar doped layer 132, and the third polar functional layer group 160 includes a third dielectric layer 161, a fourth dielectric layer 162, and a third polar doped layer 163;

[0079] The first dielectric layer 121 is stacked on the first region 101, and the first polar doped layer 122 is stacked on the first dielectric layer 121. At the second preset position, along the arrangement direction of the connection region 104 and the first region 101, the first polar doped layer 122 has a second extension 1222 extending above the connection region 104. The second extension 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;

[0080] The second dielectric layer 131 is stacked on the second region 102, and the second polar doped layer 132 is stacked on the second dielectric layer 131;

[0081] The third dielectric layer 161 is stacked on the connection region 104. The fourth dielectric layer 162 is disposed on at least a part of the first surface 1222.1. The fourth dielectric layer 162 has a tunneling function. The third polar doping layer 163 is stacked on the third dielectric layer 161 and the fourth dielectric layer 162. The third polar doping layer 163 on the third dielectric layer 161 is in communication with the third polar doping layer 163 on the fourth dielectric layer 162. At a second preset position, the third polar doping layer 163 has a first surrounding portion 1631. The first surrounding portion 1631 surrounds 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.

[0082] The first polar functional layer group 120 includes a first dielectric layer 121 and a first polar doping layer 122. The first dielectric layer 121 is stacked on the first region 101. The first polar doping layer 122 is stacked on the first dielectric layer 121. Specifically, the first dielectric layer 121 and the first polar doping layer 122 may be in direct contact, or other functional layers may be provided between the first dielectric layer 121 and the first polar doping layer 122. The first dielectric layer 121 may be a tunneling layer, such as a silicon oxide tunneling layer or other film layers having passivation and tunneling functions. Its specific type can be selected according to actual situations and is not specifically limited here.

[0083] At a second preset position, along the arrangement direction of the connection region 104 and the first region 101, the first polar doping layer 122 has a second extension portion 1222 extending above the connection region 104. 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 a part of the functional layers in the first polar functional layer group 120 has an extending portion extending above the connection region 104. That is, the first polar doping layer 122 in the first polar functional layer group 120 has a first extending portion extending above the connection region 104.

[0084] The second polar functional layer group 130 includes a second dielectric layer 131 and a second polar doping layer 132. The second dielectric layer 131 is stacked on the second region 102. The second polar doping layer 132 is stacked on the second dielectric layer 131.

[0085] The third dielectric layer 161 is stacked on the connection region 104, and the fourth dielectric layer 162 is disposed on at least a part of the first surface 1222.1, that is, the fourth dielectric layer 162 entirely or partially covers the first surface 1222.1. The third dielectric layer 161 is stacked on the connection region 104, that is, when the first region 101 and the second region 102 are adjacent to each other, the third dielectric layer 161 is stacked on the side wall between the first region 101 and the second region 102; when there is another region (such as the trench region 103) between the first region 101 and the second region 102, the third dielectric layer 161 may be disposed only on the bottom surface of the connection region 104, or may be disposed on the bottom surface of the connection region 104 and extend to the side wall between the connection region 104 and the first region 101. Specifically, the third dielectric layer 161 on the side wall between the connection region 104 and the first region 101 may be connected or disconnected from the fourth dielectric layer 162, which is not limited herein. The fourth dielectric layer 162 has a tunneling function. The fourth dielectric layer 162 may be an oxide layer, such as a silicon oxide film layer or other film layers with a passivation function, which has a tunneling function at the position covering the first surface 1222.1, and its specific type may be selected according to actual conditions, which is not specifically limited herein.

[0086] The second-polarity doped layer 132 is stacked on the third dielectric layer 161 and the fourth dielectric layer 162. The second-polarity doped layer 132 on the third dielectric layer 161 is in communication with the second-polarity doped layer 132 on the fourth dielectric layer 162, 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 there may be other functional layers between the second-polarity doped layer 132 and the third dielectric layer 161 and the fourth dielectric layer 162, which is not limited herein. The second-polarity doped layer 132 has a first surrounding portion 1631, and the first surrounding portion 1631 surrounds 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.

[0087] Specifically, at the second preset position of the connection region 104, the first wrapping portion 1631 can wrap the first surface 1222.1, the end portion, and the second surface 1222.2 of the entire second extension portion 1222. That is to say, the first wrapping portion 1631 can extend along the side surface of the connection region 104 to cover the second dielectric layer 131, wrap the end portion of the second extension portion 1222, and extend to cover the second surface 1222.2 of the second extension portion 1222. Even, it can also extend to cover a part of the first polar doping layer 122 disposed on the first region 101. In such a case, an insulating medium, such as a silicon oxide layer, a silicon nitride layer, etc. with insulating functions, can be provided between the first wrapping portion 1631 and the second surface 1222.2. When the second dielectric layer 131 only covers a part of the first surface 1222.1, the first surface 1222.1 not covered by the second dielectric layer 131 is covered by the second polar doping layer 132, and the second polar doping layer 132 disposed on the second surface 1222.2 and the second polar doping layer 132 disposed on the second dielectric layer 131 are continuous without interruption.

[0088] In this embodiment, the outer contour of the second polar doping layer 132 wrapping the first protruding portion can be the first boundary line 1001, and the edge where the second polar doping layer 132 extends to the first region 101 can be the second boundary line 1002.

[0089] In this application, the silicon substrate 110 can be a P-type silicon substrate 110 or an N-type silicon substrate 110, and it is preferably an N-type silicon substrate 110, and specifically there is no limitation here.

[0090] In a possible embodiment, during the manufacturing process, the silicon substrate 110 can be first subjected to processes such as cleaning and texturing, then the first dielectric layer 121 is deposited on the entire backlight surface of the silicon substrate 110, and then the first polar doping layer 122 is deposited on the first dielectric layer 121. Then, part of the first polar doping layer 122 and the first dielectric layer 121 are removed by etching and other means, and part of the silicon substrate 110 is removed on the backlight surface at the corresponding position. The unetched part is the first region 101, so that there is a height difference between the surface of the silicon substrate 110 in the first region 101 and the surfaces of the silicon substrates 110 in other regions (the connection region 104, the second region 102, and the trench region 103), and the second extension portion 1222 of the first polar doping layer 122 extends above the connection region 104 at the second preset position. For example, in a possible embodiment, it can be to first form a part of the depression by laser or etching, and then laterally expand the area of the depression by etching so that the first polar doping layer 122 has a second extension portion 1222 extending above the connection region 104.

[0091] Subsequently, a second dielectric layer 131 can be deposited and formed on the surfaces and sidewalls of other regions except the first region 101, as well as on the first surface 1222.1 of the second extension 1222. Then, a second polar doping layer 132 can be deposited by deposition such that the second polar doping layer 132 is stacked to cover the second dielectric layer 131, has a first surrounding portion 1631 at a second preset position, and the first surrounding portion 1631 surrounds the end of the second extension 1222 and the second surface 1222.2 of the second extension 1222 and extends to the first region 101.

[0092] Finally, the second polar doping layer 132 and the second dielectric layer 131 in the trench region 103 are removed again by etching or the like, and a part of the silicon substrate 110 is removed on the backlight surface at the corresponding position, so that there is a height difference between the surface of the silicon substrate 110 in the trench region 103 and the surface of the silicon substrate 110 in the connection region 104 and the second region 102, forming a trench.

[0093] As Figure 2 shown, in some embodiments, a first polar doping layer 122 is stacked on the first region 101, and the first polar doping layer 122 has a first edge 1004 and a second edge 1005;

[0094] A second polar doping layer 132 is stacked on the second region 102, and a third polar doping layer 163 is stacked on the connection region 104. The third polar doping layer 163 and the first polar doping layer 122 are in composite contact in the connection region 104. The second polar doping layer 132 disposed in the second region 102 has a third edge 1006;

[0095] Wherein, the plane where the second region 102 is located is the first plane. The first edge 1004 and the third edge 1006 are oppositely disposed on both sides of the trench region 103. The second edge 1005 is close to the composite contact position of the second polar doping layer 132 and the first polar doping layer 122. The projection distance of the extension line from the second edge 1005 to the third edge 1006 on the first plane is less than the projection distance from the first edge 1004 to the third edge 1006 on the first plane.

[0096] The first-polarity doping layer 122 is stacked on the first region 101. The first-polarity doping 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 doping layer 122 and the silicon substrate 110. The first-polarity doping layer 122 has two edges, namely the first edge 1004 and the second edge 1005. The edge facing the trench region 103 is the first edge 1004, and the edge facing the connection region 104 is the second edge 1005. Specifically, the second edge 1005 may be the edge of the second extension 1222 on the side close to the connection region.

[0097] The second-polarity doping layer 132 is stacked on the second region 102 and the connection region 104. The second-polarity doping 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 doping layer 132 and the silicon substrate 110. The second-polarity doping layer 132 has a third edge 1006. The third edge 1006 is on the other side of the trench region 103 and is disposed opposite to the first edge 1004 on one side of the trench region 103.

[0098] The plane where the second region 102 is located is the first plane. There may be uneven microstructures on the actual surface of the second region 102, which is not an absolute plane, but the first plane is a general plane concept. It can be understood that, on a macroscopic scale, based on the overall distribution of the second region 102 and ignoring the tiny unevenness on its surface, a plane is determined. This plane provides a unified reference benchmark for describing the distance relationship between the edges.

[0099] The projection distance of the extension line of the second edge 1005 to the third edge 1006 on the first plane is less than the projection distance of the first edge 1004 to the third edge 1006 on the first plane. In the structure of this solar cell 100, the first edge 1004, the second edge 1005, and the third edge 1006 are substantially parallel. When judging the distance between the edges, ignoring the undulations on their surfaces, along the extension directions of the edges, the projections of the edges on the first plane are approximately regarded as straight lines.

[0100] The projection of the extension line of the third edge 1006 on the first plane, that is, the extension line of the projection of the third edge 1006 on the first plane.

[0101] On the first plane, the projection lines of the edges are parallel or approximately parallel (the angle difference is small, usually not more than 2°). It can be understood that the projection lines of the edges may not be absolute straight lines, and the projection lines are approximately regarded as straight lines. The projection distance on the first plane of the extension line of the second edge 1005 to the third edge 1006 is denoted as L1. Since the third edge 1006 and the second edge 1005 are not in a relative position and are staggered from each other, the projection distance on the first plane from the second edge 1005 to the third edge 1006 is also the projection distance on the first plane of the extension line of the second edge 1005 to the third edge 1006, that is, the perpendicular 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 on the first plane from the first edge 1004 to the third edge 1006 is the perpendicular distance between the projection line of the first edge 1004 and the projection line of the third edge 1006 on the first plane, denoted as L2, and L1 < L2.

[0102] It can be understood that the perpendicular distance is also the shortest distance. Find the common perpendicular (a line perpendicular to and intersecting both lines) of two parallel lines, and the length of the common perpendicular segment is the perpendicular distance between the two parallel lines.

[0103] The projection distance on the first plane of the extension line of the second edge 1005 to the third edge 1006 is less than the projection distance on the first plane from the first edge 1004 to the third edge 1006, which means that the composite contact position is relatively closer to the first region 101, and the distance between the first region 101 and the second region 102 reaches a relatively balanced state through this setting.

[0104] In the solar cell 100, the recombination of carriers (electrons and holes) is one of the important factors affecting the cell efficiency. When the distance between the composite contact position and the first region 101 and the second region 102 is balanced, the transport path of carriers can be optimized. Since the composite contact position is closer to the first region 101, the carriers generated by the first polar doping layer 122 can be more quickly transported to the third polar doping layer 163 through the composite contact region, reducing the probability of the carriers recombining with other impurities or defects during the transport process, thereby improving the collection efficiency of the carriers and reducing the energy loss.

[0105] As Figure 1 shown, in some embodiments, the third edge 1006 is flush with the edge of the second region 102.

[0106] The trench region 103 is adjacent to the second region 102, and the edge of the second region 102 is also the edge of the trench region 103, which is the boundary line between the surface of the second region 102 and the trench region 103 on the silicon substrate 110.

[0107] The third edge 1006 is the boundary of the second-polarity doped layer 132 on the side facing the trench region 103. The two edges being flush means that the two boundaries are in the same spatial position, that is, the projected distance between the third edge 1006 and the edge of the second region 102 on the first plane is 0.

[0108] 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.

[0109] As Figure 2 shown, in some embodiments, the third edge 1006 has a preset distance from the edge of the second region 102.

[0110] The third edge 1006 has a preset distance L3 from the edge of the second region 102, and the second-polarity doped layer 132 does not have a 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 by which the third edge 1006 is indented from the edge of the second region 102, which is L3.

[0111] By setting the second-polarity doped layer 132 to have a preset distance L3 from the edge of the trench region 103 (that is, there is a platform region between the second-polarity doped layer 132 and the trench region 103), usually the outermost layer of the backlight surface covers a passivation film layer. The formed platform region can increase the mobile hydrogen content of the passivation film layer in the upper layer of the space charge region, thereby realizing enhanced hydrogen passivation in this region, reducing the recombination in the space charge region, and improving the battery performance.

[0112] As Figure 8 shown, in some embodiments, there is a first notch 111 recessed toward the first region 101 between the silicon substrate 110 of the first region 101 and the trench region 103. The first notch 111 has a first sidewall 1111 and a second sidewall 1112. The first sidewall 1111 is farther 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 included angle;

[0113] The distances from the surfaces of the second region 102 and the connection region 104 to the bottom of the trench region 103 are less than the distance from the surface of the first region 101 to the bottom of the trench region 103. There is a second notch 112 recessed toward the first region 101 between the first region 101 and the connection region 104. The second notch 112 has a third sidewall 1121 and a fourth sidewall 1122. The third sidewall 1121 is farther from the light-facing surface than the fourth sidewall 1122, and the second sidewall 1112 and the surface of the first region 101 have a second included angle;

[0114] The angle of the first included angle is less than the angle of the second included angle.

[0115] The distances from the surfaces of the second region 102 and the connecting region 104 to the bottom of the trench region 103 are less than the distance from the surface of the first region 101 to the bottom of the trench region 103. That is, the heights of the regions on the silicon substrate 110 are stepped, and there are height differences between the regions. The bottom of the trench region 103 has the lowest height. The surfaces of the second region 102 and the connecting region 104 are higher than the bottom of the trench region 103, and the surface of the first region 101 is higher than the surfaces of the second region 102 and the connecting region 104.

[0116] 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 trench region 103. This 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 trench region 103 and the first region 101. The intersection position of the first sidewall 1111 and the second sidewall 1112 is the bottom of the first notch 111. The first sidewall 1111 is farther 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.

[0117] 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 connecting region 104. This 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 connecting region 104 and the first region 101. The intersection position of the third sidewall 1121 and the fourth sidewall 1122 is the bottom of the second notch 112. The third sidewall 1121 is farther 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.

[0118] The angle of the first angle is less than the angle of the second angle. The angle formed by the first sidewall 1111 and the surface of the first region 101 is less than the angle formed by the third sidewall 1121 and the surface of the first region 101. Then the depth of the first notch 111 is greater than the depth of the second notch 112.

[0119] The depth of the first notch 111 is relatively large, which means that the internal spatial structure is more complex. When light irradiates the surface of the solar cell 100 and enters the first notch 111, due to the relatively deep notch, the light will experience more reflections inside the notch. Each reflection gives the light more opportunities to be absorbed by the battery material, which is equivalent to increasing the effective light absorption area of the battery. For example, the light that directly irradiates 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 is utilized by the battery.

[0120] The relatively deep first notch 111 can also expand the light-receiving angle range of the battery. Light rays incident at different angles are more likely to enter the interior of the first notch 111. Compared with a shallow notch or a planar structure, it can capture more light rays from different directions. In practical applications, the position of the sun changes with time and seasons, and the incident angle of light will also change accordingly. The deep structure of the first notch 111 enables the battery to better absorb light under different lighting conditions, further increasing the light absorption area.

[0121] In this embodiment, the angle of the first included angle is smaller than the angle of the second included angle, so the depth of the first notch 111 is greater than the depth of the second notch 112. The first notch 111 corresponds to the trench region 103, and the light cannot be utilized in the trench region 103. The deeper first notch 111 is beneficial to increasing the light absorption area. The second notch 112 corresponds to the connection region 104, and a second polar doping layer 132 is stacked in the connection region 104, which can absorb and utilize light. The depth of the second notch 112 is relatively shallow, and the light that is not absorbed in the second notch 112 can be absorbed and utilized in the second polar doping layer 132.

[0122] As Figure 8 shown, in some embodiments, the second sidewall 1112 and the bottom of the trench 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 trench region 103 have a third bottom edge 115;

[0123] The projection distance of the first bottom edge 113 to the third bottom edge 115 on the first plane is greater than the projection distance of the second bottom edge 114 to the third bottom edge 115 on the first plane.

[0124] The second sidewall 1112 and the bottom of the trench region 103 form a first base 113, the fourth sidewall 1122 and the surface of the connection region 104 form a second base 114, and the second region 102 and the bottom of the trench region 103 have a third base 115. The first base 113 and the third base 115 are the two boundaries of the bottom surface of the trench region 103. Usually, the first base 113, the second base 114, and the third base 115 are substantially parallel. When judging the distance between each base, ignoring the undulations on its surface, along the extension direction of each edge, the projection of each edge on the first plane is approximately regarded as a straight line, so the projections of the first base 113, the second base 114, and the third base 115 on the first plane are parallel.

[0125] The projection distance from the first base 113 to the projection of the third base 115 on the first plane is denoted as S1, and the projection distance from the second base 114 to the projection of the third base 115 on the first plane is denoted as S2, and S1 > S2.

[0126] S1 corresponds to the trench region 103. The main function of the trench region 103 is to achieve electrical isolation between different regions of the battery and prevent leakage. When S1 is larger, it means that in the projection plane, the effective isolation distance of the trench region 103 is longer. Leakage is usually caused by the flow of carriers (electrons or holes) along an undesired path. The longer isolation distance increases the difficulty for carriers to cross the trench region 103, which is equivalent to increasing the resistance to leakage. This effectively reduces the leakage between different regions inside the battery and improves the electrical performance stability of the battery.

[0127] S2 corresponds to the connection region 104. The role of the connection region 104 is to achieve electrical connection between different parts of the battery, enabling carriers to be transmitted smoothly between different regions. A smaller S2 means that the distance of the connection region 104 is relatively short, and the transmission path of carriers in the connection region 104 is shorter. The shorter transmission path can reduce the energy loss and recombination probability of carriers during transmission, ensure good electrical contact between different regions of the battery, and reduce the contact resistance. The lower contact resistance is beneficial to improving the fill factor and output power of the battery, enabling the battery to convert light energy into electrical energy output more effectively.

[0128] In this embodiment, the projection distance from the first base 113 to the projection of the third base 115 on the first plane is greater than the projection distance from the second base 114 to the projection of the third base 115 on the first plane. By optimizing the isolation performance of the trench region 103 and the contact performance of the connection region 104 through the distances respectively, the photoelectric conversion efficiency, electrical performance stability, and overall reliability of the solar cell 100 are improved.

[0129] 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-outermost film layers on the backlight surface, and the sub-outermost film layers in the first region 101 and 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 from the second-polarity doping layer 132. For example, when the wrapping part extends to cover the protruding part and covers the first-polarity doping layer 122 on a part of 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 part. 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.

[0130] As Figure 4 shown, in some embodiments, at the second preset position, the first wrapping part 1631 wraps the side walls on both sides of the end of the second extension part 1222.

[0131] The second extension part 1222 has two opposite side walls. The first wrapping part 1631 wraps the side walls on both sides of the end of the second extension part 1222, that is, except for the connection part between the second extension part 1222 and the first-polarity doping layer 122, the rest of the protruding part is completely wrapped by the first wrapping part 1631.

[0132] The first wrapping part 1631 wraps the side walls on both sides of the end of the first extension part 1221, so that the contact area between the second-polarity doping layer 132 and the first extension part 1221 is greatly increased. The larger contact area provides more composite contact transmission channels for carriers, further reducing the contact resistance.

[0133] In some embodiments, an insulating layer 140 is provided between the wrapping part and the second surface 1222.2.

[0134] The wrapping part is a part of the second-polarity doping layer 132, and the second surface 1222.2 is a surface of the first-polarity doping layer 122. The insulating layer 140 is provided between the wrapping part and the second surface 1222.2, that is, at this position, the second-polarity doping layer 132 and the first-polarity doping layer 122 are stacked, and an insulating layer 140 is provided 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, avoiding unnecessary current leakage and interference.

[0135] In this embodiment, the insulating layer 140 prevents unnecessary electron flow between the wrapping portion and the second extension 1222, reducing current leakage. This makes the electric field distribution inside the battery more reasonable, enabling carriers to be collected and transmitted to the electrodes more effectively, thereby increasing the open-circuit voltage and fill factor, and further enhancing the photoelectric conversion efficiency of the battery.

[0136] In some embodiments, the insulating layer 140 has a third extension 141 that protrudes from the second extension 1222 along the arrangement direction of the connection region 104 and the first region 101.

[0137] The insulating layer 140 is not only disposed between the wrapping portion and the second surface 1222.2, but also has a third extension 141 that protrudes from the second extension 1222 along the arrangement direction of the connection region 104 and the first region 101. The third extension 141 further enhances the insulation and isolation effects and expands the insulation range.

[0138] Assume that the length of the second extension 1222 is 80 nanometers, and the third extension 141 of the insulating layer 140 protrudes an additional 20 - 30 nanometers on the basis of the second extension 1222. This can better prevent current leakage at the junction of the connection region 104 and the first region 101.

[0139] In this embodiment, the third extension 141 increases the coverage of the insulating layer 140, especially at the edges of the connection region 104 and the first region 101, reducing the possibility of electric field concentration and current leakage at the edges. This helps protect the edge structure of the battery, preventing degradation of battery performance and shortening of battery life caused by edge leakage, thereby improving the reliability and stability of the battery.

[0140] Figure 5 to Figure 7 As shown, in some embodiments, the first surface 1222.1 and the second surface 1222.2 intersect at the end of the second extension 1222 to form a pointed end 1222.3, and the wrapping portion wraps around the pointed end 1222.3.

[0141] The end of the second extension 1222 is pointed. Even though the first wrapping portion 1631 wraps around the pointed end 1222.3, the contact between the first wrapping portion 1631 and the tip of the pointed end 1222.3 is only line-plane contact, which can reduce the contact area between the end of the second extension 1222 and the first wrapping portion 1631 and lower the recombination.

[0142] 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 by an end face. In such a case, the first wrapping portion 1631 may wrap the end face of the second extension portion 1222. When the first wrapping portion 1631 wraps 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 or an intrinsic silicon layer, and specific details are not limited herein.

[0143] In some embodiments, a hole is formed at the end of the tip portion 1222.3.

[0144] Thus, forming a hole at 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 and reduce recombination.

[0145] In some embodiments, the distance from the surface of the first polar doping layer 122 to the light-facing surface is H1, the distance from the surface of the second polar doping layer 132 to the light-facing surface is H2, and the distance from the surface of the trench region 103 to the light-facing surface is H3, where H1 > H2 > H3.

[0146] That is, when the solar cell 100 is horizontally placed with the light-facing surface facing down, the surface of the first polar doping layer 122 is higher than the surface of the second polar doping layer 132 in the second region 102, and the surface of the second polar doping layer 132 in the second region 102 is higher than the surface of the trench region 103.

[0147] The different distance settings enable light to be better absorbed by different doping layers and regions after entering the cell. H3 is the smallest, and the trench region 103 is closer to the light-facing surface. When light irradiates the cell surface, it first reaches the trench region 103. Although the trench region 103 does not perform photoelectric conversion, it can scatter and refract the light. This can make the propagation path of light inside the cell more complex and diverse, increasing the propagation distance of light in the first polar doping layer 122 and the second polar doping layer 132, thereby improving the absorption efficiency of these two layers for light.

[0148] The second polar doping layer 132 is closer to the light-facing surface than the first polar doping layer 122 (H2 < H1), and can absorb a part of the shorter wavelength light first, while the first polar doping layer 122 can absorb the remaining longer wavelength light. This layered absorption method enables the cell to make more full use of sunlight of different wavelengths, improving the spectral response range and the overall light absorption ability.

[0149] This embodiment provides a battery module, including a plurality of solar cells 100.

[0150] Multiple solar cells 100 in the battery assembly can be connected in series in sequence to form a battery string. Each battery string can be connected in series, parallel, or in a series-parallel combination to achieve the current collection and output. For example, the connection between each solar cell can be achieved by welding solder tapes, and the connection between each battery string can be achieved by a bus bar.

[0151] The battery assembly may further include a metal frame, a backsheet, a photovoltaic glass, and an encapsulant film (not shown in the figures). The encapsulant film can be filled between the light-facing surface of the solar cell 100 and the photovoltaic glass, the backlight-facing surface and the backsheet, and adjacent solar cells, etc. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulant film can be an EVA encapsulant film or a POE encapsulant film, and the specific selection can be made according to the actual situation, which is not limited herein.

[0152] The photovoltaic glass can cover the encapsulant film on the light-facing surface of the solar cell 100. The photovoltaic glass can be ultra-white glass, which has a high light transmittance, high transparency, and excellent physical, mechanical, and optical properties. For example, the light transmittance of the ultra-white glass can reach more than 92%, and it can protect the solar cell 100 without significantly affecting the efficiency of the solar cell 100. At the same time, the encapsulant film can bond the photovoltaic glass and the solar cell 100 together, and the presence of the encapsulant film can seal and insulate the solar cell 100 and prevent water and moisture.

[0153] The backsheet can be attached to the encapsulant film on the backlight-facing surface of the solar cell 100. The backsheet can protect and support the solar cell 100, and has reliable insulation, water resistance, and aging resistance. The backsheet can have multiple choices, usually it can be tempered glass, plexiglass, aluminum alloy TPT composite film, etc., and its specific setting can be made according to the specific situation, which is not limited herein. The whole composed of the backsheet, the solar cell 100, the encapsulant film, and the photovoltaic glass can be arranged on the metal frame. The metal frame is 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 installation position through the metal frame.

[0154] The beneficial effects of the battery assembly in this embodiment are equivalent to those of the above-mentioned solar cell 100, and will not be elaborated herein.

[0155] This embodiment also provides a photovoltaic system, including a battery assembly.

[0156] Photovoltaic systems can be applied in photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be applied to devices or apparatuses that generate electricity using solar energy, such as user solar power supplies, solar street lights, solar cars, solar buildings, and so on. Of course, it can be understood that the application scenarios of photovoltaic systems are not limited to this, that is to say, photovoltaic systems can be applied in all fields that require solar power generation. Taking a photovoltaic power generation system network as an example, a photovoltaic system can include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array can be an array combination of multiple battery components. For example, multiple battery components can form multiple photovoltaic arrays. The photovoltaic arrays are connected to the combiner box, and the combiner box can collect the current generated by the photovoltaic arrays. The collected current flows through the inverter and is converted into alternating current required by the mains power grid and then connected to the mains network to achieve solar power supply.

[0157] The beneficial effects of the photovoltaic system in this embodiment are equivalent to those of the above-mentioned battery components and will not be elaborated here.

[0158] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall 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 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 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, 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.

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 2, 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 3, 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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