Solar cell and photovoltaic module

Abstract

The embodiment of the utility model relates to the photovoltaic field, and provides a solar cell and a photovoltaic module, and the solar cell comprises a substrate which is provided with a first surface and a second surface which are opposite to each other; the first doped conductive layer and the second doped conductive layer are alternately distributed on the second surface, and doped elements in the first doped conductive layer and doped elements in the second doped conductive layer have different conductive types; and the connecting structure is positioned on the second surface and is positioned between the first doped conductive layer and the second doped conductive layer, and the connecting structure is electrically contacted with the first doped conductive layer and the second doped conductive layer. The embodiment of the utility model at least can improve the hot spot phenomenon of the solar cell.

Description

Technical Field

[0001] This disclosure relates to the photovoltaic field, and particularly to a solar cell and a photovoltaic module. Background Technology

[0002] Crystalline silicon solar cells have evolved from BSF and PERC to PERC+. Through continuous technological iteration and upgrades, the conversion efficiency of crystalline silicon solar cells has been increasing. Currently, the mass-produced efficiency of PERC+ has reached approximately 23.45%, approaching its theoretical limit of 24.5%. Further efficiency improvements are becoming increasingly difficult, and the potential for improvement is limited. Today, TOPcon cells, HJT cells, and back-contact cells have become new development trends in crystalline silicon solar cells, representing the forefront of international research and industrialization.

[0003] Back-contact solar cells are crystalline silicon solar cells where both the emitter and base electrodes are located on the back of the cell. Because there are no metal grid electrodes obstructing the front of the cell, back-contact cells increase light absorption efficiency and significantly improve short-circuit current. Furthermore, the use of amorphous or microcrystalline silicon, or doped silicon, to passivate the cell surface enhances open-circuit voltage. These factors effectively increase the conversion efficiency of back-contact solar cells, making them a promising technology with excellent development prospects.

[0004] Currently, back-contact solar cells are plagued by hot spot phenomena, and it is necessary to propose a solar cell to improve the hot spot phenomenon of solar cells. Utility Model Content

[0005] This disclosure provides a solar cell and a photovoltaic module that can at least improve the hot spot phenomenon of solar cells.

[0006] According to some embodiments of this disclosure, one aspect of this disclosure provides a solar cell, comprising: a substrate having a first surface and a second surface opposite to each other; a first doped conductive layer and a second doped conductive layer, the first doped conductive layer and the second doped conductive layer being alternately distributed on the second surface, wherein the doping elements in the first doped conductive layer and the doping elements in the second doped conductive layer have different conductivity types; and a connection structure located on the second surface and between the first doped conductive layer and the second doped conductive layer, the connection structure being in electrical contact with both the first doped conductive layer and the second doped conductive layer.

[0007] In some embodiments, the solar cell further includes: a spacer region located between the first doped conductive layer and the second doped conductive layer, the spacer region including a first spacer sub-region and a second spacer sub-region, the first spacer sub-region extending along a first direction and the second spacer sub-region extending along a second direction, wherein the connection structure is located on the first spacer sub-region and / or the second spacer sub-region.

[0008] In some embodiments, the shape of the orthographic projection of the connection structure onto the second surface includes at least one of a rectangle, a triangle, a parallelogram, a trapezoid, an arc, and an ellipse.

[0009] In some embodiments, the connection structure is an integral structure with the first doped conductive layer or the second doped conductive layer.

[0010] In some embodiments, the solar cell further includes: a third doped conductive layer, the third doped conductive layer being in contact with the first doped conductive layer, wherein the doping element in the third doped conductive layer has a different conductivity type than the doping element in the first doped conductive layer; wherein the connection structure is located in one of the first spacer sub-region and the second spacer sub-region; and the third doped conductive layer is located in the other of the first spacer sub-region and the second spacer sub-region.

[0011] In some embodiments, the second surface is provided with alternating first protrusions, second protrusions, and recesses located between the first protrusions and the second protrusions; the first doped conductive layer covers the surface of the first protrusion away from the first surface, and the first doped conductive layer protrudes from the sidewall of the first protrusion, and the second doped conductive layer covers the bottom surface of the second protrusion; the recesses include a flat region, a sloping region, and a textured region, the flat region being adjacent to the first protrusion; the sloping region is located between the flat region and the textured region, the sloping region being inclined relative to the flat region, and the textured region having a pyramidal structure; the third doped conductive layer is located on the flat region.

[0012] In some embodiments, the third doped conductive layer includes: a first doped conductive portion, the first doped conductive portion covering the sidewall of the first protrusion and in electrical contact with the first doped conductive layer; a second doped conductive portion, the second doped conductive portion being connected to the first doped conductive portion and covering the surface of the flat region opposite to the first surface; wherein the thickness of the first doped conductive portion is greater than the thickness of the second doped conductive portion.

[0013] In some embodiments, the first doped conductive layer protrudes from both sides of the first protrusion, and the third doped conductive layer covers the two opposite sidewalls of the first protrusion.

[0014] In some embodiments, the doping element in the third doped conductive layer is the same as the doping element in the second doped conductive layer, and the doping concentration of the doping element in the third doped conductive layer is equal to the doping concentration of the doping element in the second doped conductive layer.

[0015] According to some embodiments of this disclosure, another aspect of this disclosure also provides a photovoltaic module, including: a battery string, formed by connecting a plurality of solar cells as described in any of the above embodiments; a solder ribbon, the solder ribbon being electrically connected to at least two of the solar cells to connect adjacent solar cells in series; an encapsulating film, the encapsulating film being used to cover the surface of the battery string; and a cover plate, the cover plate being used to cover the surface of the encapsulating film facing away from the battery string.

[0016] The technical solutions provided in this disclosure have at least the following advantages:

[0017] The solar cell is provided with a connection structure for electrically connecting the first doped conductive layer and the second doped conductive layer. When the solar cell is partially shaded or an abnormality occurs in the solar cell causing localized abnormal heating, the connection structure can shunt the current, so that the current is not all concentrated in the shaded area or the abnormally heated area of ​​the solar cell, thereby reducing the current density in the shaded area or the abnormally heated area, which helps to reduce the heating power in the shaded area or the abnormally heated area, and thus can improve the hot spot effect of the solar cell. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a partial cross-sectional structural diagram of a solar cell provided in an embodiment of the present disclosure;

[0020] Figure 2 This is a first partial top view of a solar cell provided in an embodiment of the present disclosure;

[0021] Figure 3 This is a second partial top view of a solar cell provided in an embodiment of the present disclosure;

[0022] Figure 4This is a third partial top view of a solar cell provided in an embodiment of the present disclosure;

[0023] Figure 5 This is a fourth partial top view of a solar cell provided in an embodiment of the present disclosure;

[0024] Figure 6 A fifth partial top view of a solar cell provided in an embodiment of this disclosure;

[0025] Figure 7 A sixth partial top view of a solar cell provided in an embodiment of this disclosure;

[0026] Figure 8 for Figure 2 A schematic diagram of a cross-sectional structure along the cross-sectional direction MM1;

[0027] Figure 9 This is a partial three-dimensional structural diagram of a photovoltaic module provided in an embodiment of the present disclosure;

[0028] Figure 10 for Figure 9 A schematic diagram of a cross-sectional structure along the cross-sectional direction AA1. Detailed Implementation

[0029] As the background technology indicates, currently, when solar cells are partially shaded or malfunction, hot spots are easily generated on them. Hot spots refer to the phenomenon where certain areas of a solar cell or module experience significantly higher temperatures than other parts due to localized overheating. This phenomenon is usually caused by uneven current distribution or excessively high local resistance, and can severely impact cell performance and lifespan. Therefore, it is necessary to improve the hot spot phenomenon in solar cells.

[0030] This disclosure provides a solar cell and a photovoltaic module. The solar cell is provided with a connection structure for electrically connecting a first doped conductive layer 101 and a second doped conductive layer 102. When the solar cell is partially shaded or an abnormality occurs in the solar cell causing localized abnormal heating, the connection structure can shunt the current, so that the current is not all concentrated in the shaded area or the abnormally heated area of ​​the solar cell, thereby reducing the current density in the shaded area or the abnormally heated area, which helps to reduce the heating power in the shaded area or the abnormally heated area, thereby improving the hot spot effect of the solar cell.

[0031] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0032] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0033] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0034] In the description of the embodiments of this disclosure, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two groups), and "multiple pieces" refers to two or more (including two pieces).

[0035] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0036] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0037] In the accompanying drawings corresponding to the embodiments of this disclosure, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0038] In the description of embodiments of this disclosure, when a component "includes" another component, other components are not excluded unless otherwise stated, and may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Additionally, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0039] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0040] Figure 1 This is a partial cross-sectional structural diagram of a solar cell provided in an embodiment of this disclosure. Figure 2 This is a first partial top view of a solar cell provided in an embodiment of this disclosure.

[0041] refer to Figure 1 and Figure 2The solar cell includes: a substrate 100 having a first surface 110 and a second surface 120 opposite to each other; a first doped conductive layer 101 and a second doped conductive layer 102, the first doped conductive layer 101 and the second doped conductive layer 102 being alternately distributed on the second surface 120, the doping elements in the first doped conductive layer 101 and the doping elements in the second doped conductive layer 102 having different conductivity types; and a connection structure 102 located on the second surface 120 and between the first doped conductive layer 101 and the second doped conductive layer 102, the connection structure 102 being in electrical contact with the first doped conductive layer 101 and the second doped conductive layer 102.

[0042] In some embodiments, the material of the substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material may be monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon may be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0043] In some embodiments, the substrate 100 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium arsenide, perovskite, cadmium telluride, copper indium selenide, etc.

[0044] The substrate 100 can also be a sapphire substrate, a silicon substrate on an insulator, or a germanium substrate on an insulator.

[0045] The substrate 100 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type dopant element, which can be any one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type dopant element, which can be any one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0046] The substrate 100 has a first surface 110 and a second surface 120 facing each other. In some embodiments, the solar cell is a single-sided cell, in which case the first surface 110 of the substrate 100 can serve as a light-receiving surface for receiving incident light, and the second surface 120 serves as a backlight surface. In some embodiments, the solar cell is a bi-sided cell, in which case both the first surface 110 and the second surface 120 of the substrate 100 can serve as light-receiving surfaces and can both be used to receive incident light. It is understood that the backlight surface referred to in the embodiments of this application can also receive incident light, but the degree of reception of incident light is weaker than that of the light-receiving surface, and therefore it is defined as a backlight surface.

[0047] In some embodiments, a texturing process can be performed on at least one of the first or second surfaces of the substrate to form a texturized surface on at least one of the first or second surfaces of the substrate, thereby enhancing the absorption and utilization rate of incident light on the first and second surfaces of the substrate.

[0048] In some embodiments, the textured surface can be a pyramid textured surface. As a common textured surface, pyramid textured surface not only reduces the reflectivity of the substrate surface, but also forms a light trap, enhancing the substrate's absorption of incident light and improving the photoelectric conversion efficiency of the solar cell.

[0049] Specifically, if the solar cell is a single-sided cell, a textured surface, such as a pyramidal textured surface, can be formed on the light-receiving side of the substrate, while the back-lighting side of the substrate can be a polished surface, meaning the back-lighting side of the substrate is flatter than the light-receiving side. It should be noted that for single-sided cells, a textured surface can also be formed on both the light-receiving and back-lighting sides of the substrate.

[0050] If the solar cell is a bifacial cell, a textured surface can be formed on both the light-receiving side and the back-lighting side of the substrate.

[0051] The doping element in the first doped conductive layer 101 is either a P-type doping element or an N-type doping element, and the doping element in the second doped conductive layer 102 is either a P-type doping element or an N-type doping element.

[0052] The first doped conductive layer 101 can be doped polysilicon, which has good electrical conductivity and can effectively transport charge carriers.

[0053] The material of the second doped conductive layer 102 can be the same as that of the first doped conductive layer 101. This can reduce the number of types of materials in the solar cell, reduce the number of processes required to form the solar cell, and reduce the difficulty of forming the solar cell. The material of the second doped conductive layer 102 can also be doped amorphous silicon.

[0054] Understandable, Figure 1 In the example, the second surface 120 is a plane, with the first doped conductive layer 101 and the second doped conductive layer 102 flush. In reality, the second surface can be an uneven surface, and the first doped conductive layer 101 and the second doped conductive layer 102 can also be uneven. Figure 1 The thickness of the connection structure 103 in the example is less than the thickness of the first doped conductive layer 101. In fact, the thickness of the connection structure can also be equal to or greater than the thickness of the first doped conductive layer 101. Figure 1 The thickness of the connection structure 103 in the example is less than the thickness of the second doped conductive layer 102. In fact, the thickness of the connection structure can also be equal to or greater than the thickness of the second doped conductive layer 102.

[0055] In some embodiments, the solar cell further includes: a spacer region 104, which is located between the first doped conductive layer 101 and the second doped conductive layer 102. The spacer region 104 includes a first spacer sub-region 114 and a second spacer sub-region 124, wherein the first spacer sub-region 114 extends along a first direction X and the second spacer sub-region 124 extends therein along a second direction Y.

[0056] The spacer region 104 is used to isolate the first doped conductive layer 101 and the second doped conductive layer 102.

[0057] The connection structure 102 is electrically connected to the first doped conductive layer 101 and the second doped conductive layer 102, forming a leakage channel between the first doped conductive layer 101 and the second doped conductive layer 102, so as to shunt current and improve the hot spot phenomenon of the solar cell when the solar cell is partially shaded or the solar cell malfunctions and causes local abnormal heating.

[0058] The connection structure 102 is located on the first spacer sub-region 114 and / or the second spacer sub-region 124.

[0059] In some embodiments, the number of connection structures 102 is 10 to 100, for example, 10, 20, 40, 60, 80, or 100. The number of connection structures 102 within the above range ensures the shunting effect of leakage contacts on the solar cell, thereby further improving the hot spot phenomenon of the solar cell.

[0060] Understandable, Figure 2 The diagram illustrates a case where a connection structure 102 is located in the first spacer sub-region 114. In reality, a solar cell can have multiple connection structures. These multiple connection structures can all be located in the first spacer sub-region, or they can all be located in the second spacer sub-region, or some connection structures can be located in the first spacer sub-region and the other part of the connection structures can be located in the second spacer sub-region.

[0061] In some embodiments, the shape of the orthographic projection of the connection structure 102 onto the second surface 120 includes at least one of a rectangle, triangle, parallelogram, trapezoid, arc, and ellipse. That is, the shape of the connection structure 102 is a regular shape, and the leakage current of the connection structure 102 can be adjusted by adjusting the specific dimensional parameters of the above-mentioned regular shape so that the solar cell can be suitable for different application scenarios.

[0062] In some embodiments, the connection structure 102 is integral with the first doped conductive layer 101 or the second doped conductive layer 102. This configuration allows the connection structure 102 and the first doped conductive layer 101 or the second doped conductive layer 102 to be formed in the same process step, reducing the number of process steps required to form a solar cell.

[0063] In some embodiments, the shape of the orthographic projection of the connection structure 102 onto the second surface 120 is rectangular, and the two opposite short sides of the rectangle are in contact with the first doped conductive layer 101 and the second doped conductive layer 102, respectively. The length of the short side of the rectangle is 5μm to 50μm, for example, 5μm, 10μm, 20μm, 30μm, 40μm, 45μm, or 50μm; the length of the long side of the rectangle is 20μm to 200μm, for example, 20μm, 40μm, 60μm, 80μm, 100μm, 150μm, or 200μm. The dimensional parameters of the connection structure 102 affect the magnitude of the leakage current on the connection structure 102. If the parameters of the connection structure 102 are within the above range, the problem of excessive power consumption of the solar cell caused by excessive leakage current of the connection structure 102 can be avoided. Furthermore, the problem of insufficient leakage current of the connection structure 102, making it difficult to achieve current shunting effect in the shaded or abnormal areas of the battery, can also be avoided.

[0064] Figure 3 This is a second partial top view of a solar cell provided in an embodiment of this disclosure.

[0065] refer to Figure 1 and Figure 3In some embodiments, the shape of the orthographic projection of the connection structure 102 on the second surface 120 is trapezoidal. The trapezoid includes a first base and a second base arranged relatively parallel to each other. The first base of the trapezoid is in contact with one of the first doped conductive layer 101 and the second doped conductive layer 102, and the second base of the trapezoid is in contact with the other of the first doped conductive layer 101 and the second doped conductive layer 102. The length of the first base is 5μm to 50μm, for example, 5μm, 10μm, 20μm, 30μm, 40μm, 45μm or 50μm. The length of the second base is 5μm to 50μm, for example, 5μm, 10μm, 20μm, 30μm, 40μm, 45μm or 50μm. The distance between the first base and the second base is 20μm to 200μm, for example, 20μm, 40μm, 60μm, 80μm, 100μm, 150μm or 200μm. The size parameters of the connection structure 102 affect the leakage current on the connection structure 102. If the size parameters of the connection structure 102 are within the above range, the problem of excessive power consumption of solar cells caused by excessive leakage current of the connection structure 102 can be avoided. It can also avoid the problem of insufficient leakage current of the connection structure 102, which makes it difficult to achieve the current diversion effect in the shaded or abnormal areas of the battery.

[0066] Figure 4 This is a third partial top view of a solar cell provided in an embodiment of this disclosure.

[0067] refer to Figure 1 and Figure 4 In some embodiments, the shape of the orthographic projection of the connection structure 102 on the second surface 120 is a triangle. One vertex of the triangle contacts one of the first doped conductive layer 101 and the second doped conductive layer 102, and the base opposite the vertex contacts the other of the first doped conductive layer 101 and the second doped conductive layer 102. The length of the base is 5μm to 50μm, for example, 5μm, 10μm, 20μm, 30μm, 40μm, 45μm or 50μm. The distance between the vertex and the base is 20μm to 200μm, for example, 20μm, 40μm, 60μm, 80μm, 100μm, 150μm or 200μm. The size parameters of the connection structure 102 affect the leakage current on the connection structure 102. If the parameters of the connection structure 102 are within the above range, the problem of excessive power consumption of the solar cell caused by excessive leakage current of the connection structure 102 can be avoided. It can also avoid the problem of insufficient leakage current of the connection structure 102, which makes it difficult to achieve the current diversion effect of the battery shaded area or abnormal heat generation area.

[0068] Figure 5 This is a fourth partial top view of a solar cell provided in an embodiment of this disclosure.

[0069] refer to Figure 1 and Figure 5 In some embodiments, the shape of the orthographic projection of the connection structure 102 on the second surface 120 is a parallelogram. The parallelogram includes a first base and a second base arranged relatively parallel to each other. The first base of the trapezoid contacts one of the first doped conductive layer 101 and the second doped conductive layer 102, and the second base of the trapezoid contacts the other of the first doped conductive layer 101 and the second doped conductive layer 102. The length of the first base is 5μm to 50μm, and the length of the second base is 5μm to 50μm, for example, 5μm, 10μm, 20μm, 30μm, 40μm, 45μm or 50μm. The distance between the first base and the second base is 20μm to 200μm, for example, 20μm, 40μm, 60μm, 80μm, 100μm, 150μm or 200μm. The size parameters of the connection structure 102 affect the leakage current on the connection structure 102. If the parameters of the connection structure 102 are within the above range, the problem of excessive power consumption of the solar cell caused by excessive leakage current of the connection structure 102 can be avoided. It can also avoid the problem of insufficient leakage current of the connection structure 102, which makes it difficult to achieve the current diversion effect in the shaded area or abnormal area of ​​the battery.

[0070] Figure 6 This is a fifth partial top view of a solar cell provided in an embodiment of this disclosure.

[0071] refer to Figure 1 and Figure 6 In some embodiments, the shape of the orthographic projection of the connection structure 102 on the second surface 120 is an arc shape. The arc edge is in electrical contact with one of the first doped conductive layer 101 and the second doped conductive layer 102, and the bottom edge of the arc is in electrical contact with the other of the first doped conductive layer 101 and the second doped conductive layer 102. The length of the bottom edge is 0.5μm to 3μm, for example, 0.5μm, 1μm, 1.5μm, 2μm, 0.5μm or 3μm. The maximum distance between the arc edge and the bottom edge is 20μm to 200μm, for example, 20μm, 40μm, 60μm, 80μm, 100μm, 150μm or 200μm. The size parameters of the connection structure 102 affect the leakage current on the connection structure 102. If the parameters of the connection structure 102 are within the above range, the problem of excessive power consumption of the solar cell caused by excessive leakage current of the connection structure 102 can be avoided. It can also avoid the problem of insufficient leakage current of the connection structure 102, which makes it difficult to achieve the current diversion effect in the shaded area or abnormal area of ​​the battery.

[0072] Figure 7 This is a sixth partial top view of a solar cell provided in an embodiment of this disclosure.

[0073] refer to Figure 1 and Figure 7 In some embodiments, the orthographic projection of the connection structure 102 onto the second surface 120 is elliptical; the length of the major semi-axis of the ellipse is 20μm to 200μm, for example, 20μm, 40μm, 60μm, 80μm, 100μm, 150μm, or 200μm, and the length of the minor semi-axis of the ellipse is 5μm to 50μm, for example, 5μm, 10μm, 20μm, 30μm, 40μm, 45μm, or 50μm. The dimensional parameters of the connection structure 102 affect the magnitude of the leakage current on the connection structure 102. When the parameters of the connection structure 102 are within the above-mentioned range, the problem of excessive power consumption of the solar cell due to excessive leakage current of the connection structure 102 can be avoided. Furthermore, the problem of insufficient leakage current of the connection structure 102, making it difficult to achieve current shunting effects in the shaded or abnormal areas of the battery, can also be avoided.

[0074] Figure 8 for Figure 2 A schematic diagram of a cross-sectional structure along the cross-sectional direction MM1.

[0075] Reference Figure 2 and Figure 8 In some embodiments, the solar cell further includes: a third doped conductive layer 105, which is electrically in contact with the first doped conductive layer 101, wherein the doping element in the third doped conductive layer 105 has a different conductivity type than the doping element in the first doped conductive layer 101; wherein the connection structure 102 is located in one of the first spacer sub-region 114 and the second spacer sub-region 124; and the third doped conductive layer 105 is located in the other of the first spacer sub-region 114 and the second spacer sub-region 124.

[0076] The third doped conductive layer 105 is used for electrical contact with the first doped conductive layer 101, and the doping elements in the third doped conductive layer 105 have different conductivity types than the doping elements in the first doped conductive layer 101, so as to form a leakage channel between the first doped conductive layer 101 and the third doped conductive layer 105. When the solar cell is partially shaded or the solar cell malfunctions and causes local heat abnormality, the leakage channel will shunt the current to improve the impact of hot spot phenomenon.

[0077] The connecting structure 102 is located in one of the first spacer sub-region 114 and the second spacer sub-region 124; the third doped conductive layer 105 is located in the other of the first spacer sub-region 114 and the second spacer sub-region 124. This arrangement, distributing the connecting structure 102 and the third doped conductive layer 105 across the two spacer sub-regions, disperses the two leakage channels formed by the connecting structure 102 and the third doped conductive layer 105. This avoids the problem of heat concentration caused by excessive current concentration in one area when the connecting structure 102 and the third doped conductive layer 105 are concentrated in one area.

[0078] Understandably, exemplarily, Figure 2 and Figure 8 The illustration only shows the case where the connection structure 102 is located on the first spacer sub-region 114 and the third doped conductive layer 105 is located on the second spacer sub-region 124. In reality, the connection structure can also be located on the second spacer sub-region and the third doped conductive layer can be located on the first spacer sub-region.

[0079] In some embodiments, the doping element in the third doped conductive layer 105 is the same as the doping element in the second doped conductive layer 102, and the doping concentration of the doping element in the third doped conductive layer 105 is equal to the doping concentration of the doping element in the second doped conductive layer 102. With this configuration, the third doped conductive layer 105 and the second doped conductive layer 102 can be doped in the same process step, thereby reducing the number of process steps in forming the solar cell and improving the fabrication efficiency of the solar cell.

[0080] In some embodiments, the second surface 120 is provided with alternating first protrusions 130 and second protrusions 140, and a recess 150 located between the first protrusions 130 and the second protrusions 140; a first doped conductive layer 101 covers the surface of the first protrusion 130 away from the first surface 110, and the first doped conductive layer 101 protrudes from the sidewall of the first protrusion 130, and a second doped conductive layer 102 covers the bottom surface of the second protrusion 140; the recess 150 includes a flat region 160, a ramp region 170 and a textured region 180, the flat region 160 is adjacent to the first protrusion 130; the ramp region 170 is located between the flat region 160 and the textured region 180, the ramp region 170 is inclined relative to the flat region 160, and the textured region 180 has a pyramid structure; a third doped conductive layer 105 is located on the flat region 160.

[0081] The first doped conductive layer 101 is provided to protrude from the sidewall of the first protrusion 130, and this protruding part of the first doped conductive layer 101 is used as a contact window for the third doped conductive layer 105 to contact it, thereby forming a leakage channel between the first doped conductive layer 101 and the third doped conductive layer 105. This leakage channel will shunt current when the solar cell is partially shaded or when the solar cell malfunctions and causes localized abnormal heating, thereby improving the impact of hot spot phenomenon. Secondly, the first doped conductive layer 101 protrudes from the sidewall of the first protrusion 130, which can protect the third doped conductive layer 105 located below the first doped conductive layer 101. This makes it easier to retain the third doped conductive layer 105 located below the first doped conductive layer 101 to construct a good leakage path. Moreover, during the formation of the third doped conductive layer 105, since the first doped conductive layer 101 protrudes from the sidewall of the first protrusion 130, the surface of the third doped conductive layer 105 can be prevented from being eroded by the etching reagent, so as to construct a relatively complete leakage channel on the back of the solar cell. The complete leakage channel can provide a uniform transport path for charge carriers, avoid current concentration in certain areas, reduce local resistance increase and heat accumulation, and the uniform current distribution reduces the risk of hot spots caused by excessive local current.

[0082] It is understandable that the heights of the first protrusion 130, the second protrusion 140, and the recess 150 can be different. These different heights refer to the different thicknesses of the substrate 100 at the locations corresponding to the first protrusion 130, the second protrusion 140, and the recess 150. The recess 150 is a spacer region 104 between the first doped conductive layer 101 and the second doped conductive layer 102. The recess 150 isolates the first protrusion 130 and the second protrusion 140, preventing direct contact between them and avoiding the formation of additional recombination centers beyond the PN junction. This prevents increased carrier recombination and reduced battery efficiency. The recess 150 also increases electrical isolation between the first protrusion 130 and the second protrusion 140, reducing leakage current.

[0083] The flat region 160 corresponds to the portion of the first doped conductive layer 101 that protrudes from the first protrusion 130. During the formation of the third doped conductive layer 105, due to the protection of the first doped conductive layer 101, a portion of the third doped conductive layer 105 located on the surface of the recess 150 is retained. Subsequently, during the formation of the textured region 180 within the recess 150, this retained portion of the third doped conductive layer 105 protects part of the recess 150 from being etched, thus forming the flat region 160, the slope region 170, and the textured region 180.

[0084] The flat region 160 in the recess 150 is used to support the third doped conductive layer 105, and the slope region 170 is used to form a transition bridge between the flat region 160 and the textured region 180. The morphological difference between the flat region 160 and the textured region 180 may cause the concentration of mechanical stress. The slope region 170 can also disperse stress through the gradually changing surface morphology, so as to avoid cracks or damage to the cell at the junction due to stress concentration. The textured region 180 is used to increase the light reflection capability in the recess 150, reflecting the light incident on the back side back into the substrate 100, thereby improving the light absorption capability of the solar cell.

[0085] It should be noted that the flat area 160 here is relatively flat compared to the velvet area 180, not that the surface of the flat area 160 is absolutely flat.

[0086] In some embodiments, the third doped conductive layer 105 includes: a first doped conductive portion 115, which covers the sidewall of the first protrusion 130 and is in electrical contact with the first doped conductive layer 101; and a second doped conductive portion 125, which is connected to the first doped conductive portion 115 and covers the surface of the flat region facing away from the first surface 110; wherein the thickness of the first doped conductive portion 115 is greater than the thickness of the second doped conductive portion 125. Compared with the technical solution of setting the entire third doped conductive layer 105 of the same thickness to be in electrical contact with the first doped conductive layer 101, setting the third doped conductive layer 105 into first doped conductive portions 115 and second doped conductive portions 125 of different thicknesses, and achieving electrical contact with the first doped conductive layer 101 through the first doped conductive portion 115, the volume of the third doped conductive layer 105 can be reduced, thereby saving the material cost of the third doped conductive layer 105.

[0087] In some embodiments, the first doped conductive layer 101 protrudes from both sides of the first protrusion 130, and the third doped conductive layer 105 covers the two opposite sidewalls of the first protrusion 130. The presence of the third doped conductive layer 105 on both sides of the first protrusion 130 increases the current shunting effect of the third doped conductive layer 105, further improving the hot spot effect of the solar cell.

[0088] In some embodiments, the solar cell further includes a first tunneling layer 106, which is located between the first doped conductive layer 101 and the substrate 100. The material of the first tunneling layer 106 may be silicon oxide, silicon nitride, or silicon oxynitride, etc. The first tunneling layer 106 serves to passivate the substrate 100 on the one hand, and does not affect the transport of charge carriers on the other hand. It can also buffer the interfacial tension between the substrate 100 and the first doped conductive layer 101, thereby reducing the loss in the transport of charge carriers.

[0089] In some embodiments, the solar cell further includes a second tunneling layer 107 located between the second doped conductive layer 102 and the substrate 100. The material of the second tunneling layer 107 can be the same as that of the first tunneling layer 106, such as silicon oxide, silicon nitride, or silicon oxynitride. Using the same material for the second tunneling layer 107 as the first tunneling layer 106 can reduce the number of material types in the solar cell, reduce the number of processes required to form the solar cell, and lower the difficulty of forming the solar cell.

[0090] In some embodiments, the solar cell further includes a third tunneling layer 108, which is located between the third doped conductive layer 105 and the substrate 100. The material of the third tunneling layer 108 can be the same as that of the second tunneling layer 107. Thus, the third tunneling layer 108 and the second tunneling layer 107 can be formed in the same process step, which can reduce the number of process steps in forming the solar cell.

[0091] This disclosure also provides a photovoltaic module in some embodiments, which may include the solar cells as described in some or all of the above embodiments. It should be noted that parts that are the same as or corresponding to those described in the above embodiments can be referred to in the above embodiments, and will not be repeated hereafter.

[0092] Figure 9 This is a partial three-dimensional structural diagram of a photovoltaic module provided in an embodiment of the present disclosure. Figure 10 for Figure 9 A schematic diagram of a cross-sectional structure along the cross-sectional direction AA1.

[0093] refer to Figure 9 and Figure 10 The photovoltaic module includes: a battery string, which includes: a plurality of solar cells 40 as in any of the above embodiments; and a solder ribbon 43 electrically connected to at least two solar cells 40 to connect adjacent solar cells 40 in series.

[0094] The photovoltaic module also includes an encapsulating film 41, which is used to cover the surface of the cell string.

[0095] The photovoltaic module also includes a cover plate 42, which is used to cover the surface of the encapsulating film 41 away from the cell string.

[0096] In some embodiments, the encapsulating film 41 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front or back sides of the solar cell, and the second encapsulating layer covers the other of the front or back sides of the solar cell. Specifically, at least one of the first or second encapsulating layer can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene elastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first or second encapsulating layer can also be an EP film, an EPE film, or a PVP film. Here, EP film refers to a co-extruded film composed of stacked EVA film and POE film; EPE film refers to a co-extruded film formed by sequentially stacking EVA film, POE film, and EVA film; and PVP film refers to a co-extruded film formed by stacking POE film, EVA film, and POE film. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0097] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After lamination, the photovoltaic module will no longer have the concept of a first encapsulation layer and a second encapsulation layer. That is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0098] In some embodiments, the cover plate 42 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulating film 41 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0099] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this disclosure. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.

Claims

1. A solar cell, characterized in that, include: A substrate having opposing first and second surfaces; A first doped conductive layer and a second doped conductive layer are alternately distributed on the second surface. The doping elements in the first doped conductive layer and the doping elements in the second doped conductive layer have different conductivity types. A connection structure is located on the second surface and between the first doped conductive layer and the second doped conductive layer, and the connection structure is in electrical contact with the first doped conductive layer and the second doped conductive layer.

2. The solar cell according to claim 1, characterized in that, The solar cell also includes: The spacer region is located between the first doped conductive layer and the second doped conductive layer. The spacer region includes a first spacer sub-region and a second spacer sub-region. The first spacer sub-region extends along a first direction, and the second spacer sub-region extends along a second direction. The connection structure is located on the first spacer sub-region and / or the second spacer sub-region.

3. The solar cell according to claim 2, characterized in that, The shape of the orthographic projection of the connecting structure onto the second surface includes at least one of a rectangle, triangle, parallelogram, trapezoid, arc, and ellipse.

4. The solar cell according to any one of claims 1 to 3, characterized in that, The connection structure is an integral structure with the first doped conductive layer or the second doped conductive layer.

5. The solar cell according to claim 2, characterized in that, The solar cell also includes: A third doped conductive layer is electrically contacted with the first doped conductive layer, and the doping elements in the third doped conductive layer have different conductivity types than the doping elements in the first doped conductive layer. The connection structure is located in one of the first spacer sub-region and the second spacer sub-region; the third doped conductive layer is located in the other of the first spacer sub-region and the second spacer sub-region.

6. The solar cell according to claim 5, characterized in that, The second surface is provided with alternating first protrusions, second protrusions, and recesses located between the first protrusions and the second protrusions; the first doped conductive layer covers the surface of the first protrusion away from the first surface, and the first doped conductive layer protrudes from the sidewall of the first protrusion, and the second doped conductive layer covers the bottom surface of the second protrusion. The recessed portion includes a flat area, a sloping area, and a velvety area. The flat area is adjacent to the first protrusion. The sloping area is located between the flat area and the velvety area, and the sloping area is inclined relative to the flat area. The velvety area has a pyramid structure. The third doped conductive layer is located on the flat region.

7. The solar cell according to claim 6, characterized in that, The third doped conductive layer includes: A first doped conductive portion covers the sidewall of the first protrusion and is in electrical contact with the first doped conductive layer. A second doped conductive portion is connected to the first doped conductive portion, and the second doped conductive portion covers the surface of the flat region away from the first surface; The thickness of the first doped conductive portion is greater than the thickness of the second doped conductive portion.

8. The solar cell according to claim 6, characterized in that, The first doped conductive layer protrudes from both sides of the first protrusion, and the third doped conductive layer covers the two opposite sidewalls of the first protrusion.

9. The solar cell according to claim 5, characterized in that, The doping element in the third doped conductive layer is the same as the doping element in the second doped conductive layer, and the doping concentration of the doping element in the third doped conductive layer is equal to the doping concentration of the doping element in the second doped conductive layer.

10. A photovoltaic module, characterized in that, include: A battery string, comprising multiple solar cells connected together as described in any one of claims 1 to 9; A solder strip, which is electrically connected to at least two of the solar cells to connect adjacent solar cells in series; An encapsulating film, the encapsulating film being used to cover the surface of the battery string; A cover plate for covering the surface of the encapsulating film facing away from the battery string.

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