Solar cell and photovoltaic module

Abstract

Solar cell comprising: a substrate having a first surface and a second surface adjacent to each other on the substrate, at least one of which is a side surface of the substrate; wherein the substrate further comprises a common multiple pyramid body having a common surface on common prismatic edges and / or common corners where the first surface and the second surface are adjacent; wherein the common multiple pyramid body, when viewed in the direction of the first surface, comprises a first pyramid structure formed by enclosing a plurality of first triangular surfaces and a plurality of third triangular surfaces, and wherein the common multiple pyramid body, when viewed in the direction of the second surface, comprises a second pyramid structure formed by enclosing a plurality of second triangular surfaces and a plurality of third triangular surfaces, and wherein the third triangular surface is the common surface and the triangular surfaces in the first triangular surface, the second triangular surface and the third triangular surface have the shape of a triangle or a quasi-triangle.

Description

FIELD OF TECHNOLOGY

[0001] This application relates to the field of a solar cell, in particular a solar cell and a photovoltaic module. STATE OF THE ART

[0002] The substrate of a solar cell is its core component. However, in current solar cells, the substrate still exhibits, among other things, difficult-to-remove defects and contamination by impurities that are difficult to completely remove in some locations. These problems limit further improvements in the photoelectric conversion efficiency of solar cells. SUMMARY OF THE INVENTION

[0003] To solve the above technical problem, this application discloses a solar cell and a photovoltaic module.

[0004] In a first aspect, the present application provides a solar cell comprising: a substrate having a first surface and a second surface adjacent to each other on the substrate, at least one of which is a side surface of the substrate; wherein the substrate further comprises a common multiple pyramid body having a common surface on common prismatic edges and / or common corners where the first surface and the second surface are adjacent; wherein the common multiple pyramid body, when viewed in the direction of the first surface, comprises a first pyramid structure formed by enclosing a plurality of first triangular surfaces and a plurality of third triangular surfaces, and wherein the common multiple pyramid body, when viewed in the direction of the second surface, comprises a second pyramid structure formed by enclosing a plurality of second triangular surfaces and a plurality of third triangular surfaces, and wherein the third triangular surface is the common surface and the triangular surfaces in the first triangular surface, the second triangular surface and the third triangular surface have the shape of a triangle or a quasi-triangle.

[0005] Furthermore, the common multiple pyramid body is a common double pyramid body and wherein the first surface is a first side surface of the substrate, the second surface includes a first bottom surface which is any one of the light-receiving surface, the back surface and a second side surface of the substrate, and the common double pyramid body is provided on the common prismatic edge in a zone where the first surface and the first bottom surface are adjacent.

[0006] Furthermore, the common multiple pyramid body is a common triple pyramid body and wherein the first surface is a first side surface of the substrate, the second surface includes a first bottom surface and a second bottom surface, the first bottom surface is the light-receiving surface or the back surface of the substrate, the second bottom surface is the second side surface adjacent to the first side surface, and the common triple pyramid body is provided on the common corner in a zone where the first surface, the first bottom surface, and the second bottom surface are adjacent.

[0007] Furthermore, the solar cell is a disc cell, the substrate has a cut side surface and the side surface of the substrate includes the cut side surface and / or the first surface and the second surface are perpendicular to each other.

[0008] Furthermore, the first pyramid structure has, in an orthogonal projection of the first surface, a first diagonal with a length L1, and 0.1 µm ≤ L1 ≤ 7 µm; the second pyramid structure has, in an orthogonal projection of the second surface, a second diagonal with a length L2, and 0.1 µm ≤ L2 ≤ 7 µm; and For each of the common multiple pyramid bodies, 0.5 ≤ L1 / L2 ≤ 2.

[0009] Furthermore, the first pyramid structure has a first height H1 in a direction perpendicular to the first surface, and 0.1 µm ≤ H1 ≤ 3 µm; the second pyramid structure has a second height H2 in a direction perpendicular to the second surface, and 0.1 µm ≤ H2 ≤ 3 µm; and For each of the common multiple pyramid bodies, 0.5 ≤ H1 / H2 ≤ 2.

[0010] Furthermore, the common multiple pyramid body is arranged along the longitudinal direction of the common prismatic edge and wherein the common prismatic edge has a central region and edge regions arranged on both sides of the central region; wherein the length of the diagonal of the common multiple pyramid body arranged in the central region is smaller than that of the diagonal of the common multiple pyramid body arranged in the edge regions; the height of the common multiple pyramid body arranged in the central region is smaller than that of the common multiple pyramid body arranged in the edge regions and / or for a region of length of 100 µm corresponding to the common prismatic edge, the number of common multiple pyramid bodies is greater than or equal to 1.

[0011] Furthermore, the number of common multiple pyramid bodies for the region with a length of 100 µm, which corresponds to the common prismatic edge, is at least 10.

[0012] Furthermore, a plurality of third pyramid structures are provided on the first surface, and a plurality of fourth pyramid structures are provided on the second surface.

[0013] Furthermore, the first pyramid structure has, in an orthogonal projection of the first surface, a first diagonal with a length L1, and 0.1 µm ≤ L1 ≤ 7 µm, and the third pyramid structure has a third diagonal with a length L3, and 0.1 µm ≤ L3 ≤ 7 µm and 0.5 ≤ L3 / L1 ≤ 2; and wherein the second pyramid structure has a second diagonal with a length L2 in an orthogonal projection of the second surface, and 0.1 µm ≤ L2 ≤ 7 µm, and the fourth pyramid structure has a fourth diagonal with a length L4, and 0.1 µm ≤ L4 ≤ 7 µm and 0.5 ≤ L4 / L2 ≤ 2.

[0014] Furthermore, the first pyramid structure has a first height H1 in the direction perpendicular to the first surface, and 0.1 µm ≤ H1 ≤ 3 µm, and the third pyramid structure has a third height H3, and 0.1 µm ≤ H3 ≤ 5 µm and 0.5 ≤ H3 / H1 ≤ 2; and wherein the second pyramid structure has a second height H2 in the direction perpendicular to the second surface, and 0.1 µm ≤ H2 ≤ 3 µm, and the fourth pyramid structure has a fourth height H4, and 0.1 µm ≤ H4 ≤ 5 µm and 0.5 ≤ H4 / H2 ≤ 2.

[0015] The solar cell also includes: a semiconductor layer arranged on the light-receiving surface and / or the back side of the substrate; a passivation layer arranged on a surface of the semiconductor layer facing away from the substrate and arranged on the side surface of the substrate, and an electrode.

[0016] The solar cell also includes: the substrate; a first semiconductor layer and a first electrode provided sequentially in a P-type conductive region on the back side of the substrate; and a second semiconductor layer and a second electrode provided sequentially in an N-type conductive region on the back side of the substrate; wherein the first semiconductor layer and the second semiconductor layer are arranged alternately in an interlocking manner and an insulation region is present between the first semiconductor layer and the second semiconductor layer.

[0017] The solar cell also includes: a first passivation layer provided on a surface of the first semiconductor layer facing away from the substrate; a second passivation layer provided on a surface of the second semiconductor layer facing away from the substrate; a third passivation layer provided on the light-receiving surface of the substrate; and a fourth passivation layer provided on the side surface of the substrate.

[0018] Furthermore, a first dielectric layer is provided between the substrate and the first semiconductor layer and a second dielectric layer is provided between the substrate and the second semiconductor layer.

[0019] Furthermore, the first semiconductor layer is a first layer of doped polycrystalline silicon or a first layer of doped amorphous silicon deposited on the back side of the substrate, and the second semiconductor layer is a second layer of doped polycrystalline silicon or a second layer of doped amorphous silicon deposited on the second dielectric layer; and / or wherein the first passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer, the second passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer, the third passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer, and the fourth passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer; and / or wherein the first dielectric layer is a silicon oxide layer, a layer of amorphous silicon, a layer of polycrystalline silicon and / or a silicon nitride layer and the second dielectric layer is a silicon oxide layer, a layer of amorphous silicon, a layer of polycrystalline silicon and / or a silicon nitride layer.

[0020] The solar cell also includes: the substrate; a first semiconductor layer and a first electrode provided sequentially on the light-receiving surface of the substrate, wherein the first semiconductor layer and the substrate each have different conductivity types; and a dielectric layer, a second semiconductor layer and a second electrode provided sequentially on the back side of the substrate.

[0021] The solar cell also includes: a fifth passivation layer provided on a surface of the first semiconductor layer facing away from the substrate; a sixth passivation layer provided on a surface of the second semiconductor layer facing away from the substrate; and a seventh passivation layer provided on the side surface of the substrate.

[0022] Furthermore, the first semiconductor layer is formed by thermal diffusion of doped elements into the substrate, or the first semiconductor layer is a first layer of doped polycrystalline silicon or a first layer of doped amorphous silicon deposited on the back side of the substrate, and the second semiconductor layer is a second layer of doped polycrystalline silicon or a second layer of doped amorphous silicon deposited on the second dielectric layer; and / or wherein the fifth passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer or silicon nitride layer, the sixth passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer or silicon nitride layer and the seventh passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer or silicon nitride layer; and / or wherein the dielectric layer is a silicon oxide layer, a layer of amorphous silicon, a layer of polycrystalline silicon and / or a silicon carbide layer.

[0023] In a second aspect, the present application provides a photovoltaic module, wherein the photovoltaic module comprises a solar cell according to the first aspect.

[0024] Compared to the prior art, this application has at least the following advantageous effects:

[0025] Because the above-mentioned common multiple pyramid bodies are provided at the common prismatic edges and / or common corners where the first surface and the second surface of the substrate are adjacent, the solar cell of one embodiment of the present application serves to reduce defect states of the substrate surface, thereby further improving the purity of the substrate and minimizing the effect of impurity contamination on subsequent processes, thereby being helpful for increasing the photoelectric efficiency of the solar cell. SHORT DESCRIPTION OF THE CHARACTERS

[0026] To more clearly illustrate technical solutions in embodiments of the present application, a brief introduction to the figures to be used in the embodiments is provided below. Obviously, the figures in the following brief description represent only some of the embodiments of the present application. Other figures can also be obtained from these figures by a person of ordinary skill in the art without resorting to any creative work. Fig. 1 is a schematic diagram of a structure of a substrate in a solar cell of an embodiment of the present application; Fig. Figure 2 is an enlarged schematic diagram of the structure at A in Fig. 1; Fig. 3 is a schematic diagram of a structure of a common multiple pyramid body in an embodiment of the present application in a view from different directions; Fig.4 is a schematic diagram of variant structures of a triangular surface in an embodiment of the present application; Fig. 5 is a schematic structural diagram of another common multiple pyramid body in embodiments of the present application in a view from different directions; Fig. 6 is a schematic structural diagram of pyramid structures provided in a first surface and a second surface in an embodiment of the present application; Fig. 7 is a schematic structural diagram of a solar cell with back contacts of an embodiment of the present application; Fig. 8 is an SEM view of a common multiple pyramid body provided on a common prismatic edge in one embodiment of the present application; Fig.9 is an SEM view of a common multiple pyramid body provided on a common prismatic edge of an embodiment of the present application. Description of reference numbers:

[0027] 1. Substrate; a. first surface; b. second surface; b1. first subsurface; b2. second subsurface; c. common prismatic edge; d. common corner; 11. common multiple pyramid body; 111. first pyramid structure; 112. second pyramid structure; 1121. first class of a second pyramid; 1122. second class of a second pyramid; 12. third pyramid structure; 13. fourth pyramid structure; 11a. first triangular surface; 11b. second triangular surface; 11b1, first class of a second triangular surface; 11b2, first class of a second triangular surface; 11c. third triangular surface; 21. first semiconductor layer; 22. second semiconductor layer; 31. first electrode; 32. second electrode; 4. insulation region; 51. first passivation layer; 52. second passivation layer; 53. third passivation layer; 54. fourth passivation layer; 61. first dielectric layer; 62. second dielectric layer. DETAILED EMBODIMENTS

[0028] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the figures in the embodiments of the present application. It is obvious that the described embodiments are not all embodiments, but only a part of the embodiments of the present application. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without performing creative work are within the scope of the present application.

[0029] Throughout this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inside," "outside," "vertical," "horizontal," "across," "perpendicular," etc., refer to an orientation or positional relationship based on what is shown in the accompanying drawings. These terms are primarily intended to better describe this application and its embodiments and are not intended to imply any limitation that the specified device, element, or component must have a particular orientation or operate in a particular orientation.

[0030] Furthermore, some of the above terms may be used to indicate other meanings in addition to the orientation or positional relationship. For example, the term "on" may also be used in some cases to indicate a specific dependency or connection relationship. A person of ordinary skill in the art can understand the specific meaning of these terms in the present application, taking into account the specific circumstances.

[0031] Furthermore, the terms "mounted," "arranged," "having," "connected," and "connected to" are to be understood in a broad sense. For example, it may be a fixed connection, a removable connection, or a monolithic configuration; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection via an intermediate medium; or it may be an internal communication between two devices, elements, or components. A person of ordinary skill in the art may understand the specific meaning of the above terms in the present application, taking into account the specific circumstances.

[0032] Furthermore, the terms "first," "second," etc., are not used to indicate or imply a relative importance or number of the specified devices, elements, or components, but are primarily used to distinguish different devices, elements, or components (where the specific species and configurations may be the same or different). Unless otherwise noted, "plural" means two or more.

[0033] In the present application, a solar cell and a photovoltaic module are provided to improve defect states of a substrate of the solar cell and to reduce its contamination by impurities to a certain extent, so as to further increase the electrical performance of the solar cell, such as the photoelectric efficiency and so on, through these improvements.

[0034] In a first aspect, the present application provides a solar cell which, in connection with the Fig. 1 to 3. Fig. 1 is a schematic diagram of a structure of the substrate 1 in the solar cell of an embodiment of the present application, Fig. Figure 2 is an enlarged schematic diagram of the structure at A in Fig. 1, and Fig. Figure 3 is a schematic diagram of a structure of a common multiple pyramid body 11 in an embodiment of the present application, viewed from different directions. For a clear illustration of structural features of the common multiple pyramid body 11, only one common multiple pyramid body 11 is shown as an example. Fig.2 for the positions arranged at common prismatic edges c and common corners d, respectively, wherein the number of common multiple pyramid bodies 11 in the solar cell of the present application is not limited to the example of Fig. 2 is limited.

[0035] The solar cell of one embodiment of the present application comprises: a substrate 1 having a first surface a and a second surface b adjacent to each other thereon, at least one of which is a side surface of the substrate; wherein the substrate 1 further comprises common multiple pyramid bodies 11 having a common surface on the common prismatic edges c and / or common corners d where the first surface a and the second surface b are adjacent.

[0036] As in connection with the Fig. 2 and Fig.3, the common multiple pyramid body 11 comprises, when viewed in the direction of the first surface a (ie when viewed along the z-axis in the direction of the first surface a in Fig. 2) a first pyramid structure 111 formed by enclosing a plurality of first triangular surfaces 11a and a plurality of third triangular surfaces 11c; and when viewed in the direction of the second surface (ie, when viewed along the x-axis in the direction of the second surface b in Fig. 2 and / or when viewed along the y-axis in the direction of the second surface b in Fig.2) The common multiple pyramid body 11 has a second pyramid structure 112 formed by enclosing a plurality of second triangular faces 11b and a plurality of third triangular faces 11c; wherein the third triangular face 11c is a common face, and the triangular faces in the first triangular face 11a, the second triangular face 11b, and the third triangular face 11c have the shape of a triangle or a quasi-triangle.

[0037] That is, the term "common multiple pyramid body 11" in the present application means that such a polyhedral structure exists in the zone where the first face a and the second face b are adjacent. When viewed from different angles, the polyhedral structure has corresponding pyramid structures at different angles, so that some of the triangular faces in the different pyramid structures can be used as common faces, and they can thus form a common body via the common faces and other triangular faces. Because the common body shares some of the faces in the different pyramid structures, the common body constitutes a common multiple pyramid body 11.For example, a common solid obtained by utilizing the common faces of two pyramid structures that can be viewed from two different angles is known as a double pyramid common solid; and a common solid obtained by utilizing the common faces of three pyramid structures that can be viewed from three different angles is known as a triple pyramid common solid.

[0038] Of these, the pyramid structure, viewed from any angle, is formed by the inclusion of several triangular faces. These triangular faces can each be in the shape of a standard triangle or a quasitriangle. The overall shape of quasitriangles is close to that of a standard triangle due to defects such as small dimples that are missing from some faces of the pyramid structure, which is why the triangular faces used for inclusion to form the pyramid structure can have the shape of the aforementioned quasitriangle. For example, in Fig.4 shows several alternative triangular faces, where the vertices of a triangle may be sharp corners or curved corners, and small dimples may be present at the corners or sides of the triangles, while their overall shape is still generally triangular, and so on. The overall shape of the pyramid structure formed by the inclusion of these triangular faces should also be understood in the broadest sense, in that the shape of these pyramid structures may be a standard pyramid shape or a shape that approximates a pyramid in its overall profile.

[0039] When it is stated that the pyramid structures are formed by enclosing several triangular surfaces, this means that the outer surfaces of the pyramid structures are formed by enclosing these triangular surfaces. Although the base surfaces of the pyramid structures do not exist as actual structural surfaces, they can be understood as orthogonal projection surfaces of the pyramid structure on the corresponding surfaces. Taking the first pyramid structure 111 as an example, when viewed in the direction of the first surface a (i.e., when viewed along the z-axis in the direction of the first surface a in Fig.2) Only the first triangular face 11a and the third triangular face 11c are visible, which are used to enclose the outer surface of the first pyramid structure 111, and the base surface of the first pyramid structure 111 is practically invisible. However, parameters such as the shape and dimensions of the base surface of the first pyramid structure 111 can be determined by the orthogonal projection of the shape formed by enclosing the first triangular face 11a and the third triangular face 11c on the first face a.

[0040] Furthermore, a pyramid structure refers to a structure with the same or similar shape as a pyramid, and thus, the pyramid structure of the present application is not a planar structure but a three-dimensional structure. For example, although the first pyramid structure 111 can be viewed in the direction of the first face a, it can also be seen in a scanning electron micrograph that a common center exists for the first triangular face 11a and the third triangular face 11c used for inclusion to form the first pyramid structure 111, and the first pyramid structure 111 is actually a three-dimensional structure rather than a planar structure.

[0041] Furthermore, in the present application, the term "first triangular surface 11a" refers to the triangular surface located on the first surface a, the term "second triangular surface 11b" refers to the triangular surface located on the second surface b, and the third triangular surface 11c is located on both the extension surface of the first surface a and the extension surface of the second surface b, thus forming a common surface. Thus, it can also be understood that the main difference between the first triangular surface 11a, the second triangular surface 11b, and the third triangular surface 11c in the present application mainly lies in the fact that the surfaces on which they are located are arranged at different positions.

[0042] The solar cell of one embodiment of the present application contributes to further increasing the photoelectric efficiency of the solar cell due to the above-described common multiple pyramid bodies 11 provided on the common prismatic edge c and / or the common corner d, wherein the first surface a and the second surface b of the substrate 1 are adjacent, which serves to reduce the defect states on the surfaces of the substrate 1 and improve the purity of the substrate 1 to minimize effects due to contamination by impurities in the subsequent process.

[0043] First, if the pyramid structures are provided only on the first surface a or the second surface b, and the common multiple pyramid bodies 11 are not formed in the region where the two surfaces are adjacent, more defect states and a certain amount of dangling bonds will exist in the substrate 1 in the region where the two adjacent surfaces are adjacent, which is likely to result in recombination. However, in the present application, common multiple pyramid bodies 11 are provided in the region where the two surfaces are adjacent, which serves to reduce the defect states at this position and reduce the presence of dangling bonds, thereby reducing recombination.In addition, the presence of the common multiple pyramid bodies 11 also contributes to increasing the stability of the mechanical structure of the substrate 1 at the common prismatic edge c, so that the common prismatic edge c is less susceptible to physical damage during processing of the solar cell, which in turn contributes to increasing the durability and reliability of the solar cell.

[0044] Second, due to the presence of a common face, the common multi-pyramid body 11 has a smaller total surface area, which is advantageous for improving the purity of the substrate 1. Specifically, in the case where a common multi-pyramid body 11 is a common double-pyramid body, the common double-pyramid body has only 6 triangular faces compared to the total surface area of the two separate pyramids with a total of 8 triangular faces, which is reduced by 2 triangular faces, and thus has a smaller surface area. The feature of a smaller total surface area of the common multiple-pyramid body 11 contributes to reducing the possibility of impurities accumulating on the surface of the substrate 1, especially in gaps and corner areas near the common prismatic edges c, while ensuring light utilization efficiency.

[0045] As can be seen in the present application, by providing common multiple pyramid bodies 11 in the zone where the first surface a and the second surface b are adjacent, several advantages, such as a reduction in defect states, an improvement in structural stability and an increase in purity, can be brought about for the substrate 1 of the solar cell, which in turn improves the degree of adhesion of functional layers, such as passivation layers and anti-reflection layers, which are subsequently formed on the substrate 1, thus further improving the passivation capability of the solar cell and optimizing the performance of the solar cell.

[0046] As an alternative embodiment in connection with Fig. 2 and Fig.3, the common multiple pyramid body 11 is a common double pyramid body. In this embodiment, the common double pyramid body can be formed by two adjacent surfaces and their common prismatic edge c. Of these, the first surface a is a first side surface of the substrate 1, and the second surface b includes a first sub-surface b1. The first sub-surface b1 is the light-receiving surface, the back surface, or a second side surface of the substrate 1. A common double pyramid body is provided on the common prismatic edge c, which is located in the zone where the first surface a and the first sub-surface b1 are adjacent.The structural feature of the common double pyramid body formed in the zone where the two surfaces are adjacent is advantageous to optimize the reflection path of light, effectively guide more light to the body of the substrate 1, and ensure the light utilization rate.

[0047] For example, in a case where the first subsurface b1 is the light-receiving surface or back surface of the substrate 1, the above-mentioned common double pyramid body is formed on the common prismatic edge c in the region where the first side surface and the light-receiving surface (or back surface) are adjacent. An advantage of this structure is that, although the side surface of the solar cell is not directly exposed to sunlight, the formation of the above-mentioned shaped common double pyramid body between the side surface and the light-receiving surface (or back surface) is equivalent to forming an additional light absorption zone on the side surface of the substrate 1, which serves to increase light scattering, reduce light reflection, improve the utilization of the side surface for reflecting light, and further increase the light utilization rate.

[0048] In another case, where the first sub-substrate b1 is a second side surface of the substrate 1, the above-mentioned common double pyramid body is formed on the common prismatic edge c in the zone where the first side surface and the second side surface are adjacent. The advantages of this structure are that it facilitates the redirection of light reflected from the side surfaces back to the light-receiving surface, reduces light leakage from the side surfaces, and ensures that more light can be absorbed and utilized by the cell.Furthermore, compared to the case where the common multiple pyramid bodies 11 are not provided at the common prismatic edge c, the common double pyramid bodies located at the common prismatic edge c also serve to improve the structural stability of the substrate 1 and provide better resistance to mechanical stress during the solar cell manufacturing process.

[0049] As an alternative embodiment, which is Fig.2, the common multiple pyramid body 11 is a common triple pyramid body. In this embodiment, the common triple pyramid body can be formed by three adjacent surfaces and their common corner d. Of these, the first surface a is a first side surface of the substrate 1, and the second surface b includes a first sub-surface b1 and a second sub-surface b2. The first sub-surface b1 is the light-receiving surface or back surface of the substrate 1, and the second sub-surface b2 is a second side surface adjacent to the first side surface. A common triple pyramid body is formed on the common corner d, which is located in the zone where the first surface a, the first sub-surface b1, and the second sub-surface b2 are adjacent.The term “common triple pyramid body” refers to a common body formed by the three pyramid structures when viewed from three different perspectives, some of which share triangular surfaces.

[0050] The structure of the common triple pyramid body is described below with reference to the Fig. 2 and Fig. 5. When viewed in the direction of the first surface a (ie in the direction of the first surface a in the direction of the z-axis in Fig. 2) the common triple pyramid body comprises a first pyramid structure 111 enclosed by a first triangular surface 11a and a plurality of third triangular surfaces 11c. When viewed in the direction of the light-receiving surface (ie in the direction of the light-receiving surface in the direction of the y-axis in Fig.2) the common triple pyramid body comprises a second pyramid 1121 of a first class, which is enclosed by second triangular faces 11b1 of a first class and several third triangular faces 11c. When viewed in the direction of the second face (ie in the direction of the second face in the direction of the x-axis in Fig.2) the common triple pyramid body comprises a second pyramid 1122 of a second class, which is enclosed by several second triangular surfaces 11b2 of a second class and several third triangular surfaces 11c.Here, the term “first triangular surface 11a” refers to triangular surfaces arranged on the first surface a, the term “second triangular surfaces 11b1 of the first class” refers to triangular surfaces arranged on the first sub-surface b1 of the second surface b, the term “second triangular surfaces 11b2 of the second class” refers to triangular surfaces arranged on the second sub-plane b2 of the second surface b, and the term “third triangular surfaces 11c” refers to triangular surfaces arranged simultaneously on an extension surface of the first surface a, an extension surface of the first sub-surface b1 and an extension surface of the second sub-surface b2, and thus the third triangular surfaces 11c are common surfaces.

[0051] Compared with the individually provided pyramid structures, the common triple pyramid body provided in the zone where the three surfaces are adjacent has more common surfaces, and thus the surface area is smaller, which is more conducive to reducing defect states of the substrate 1 and improving the cleanliness of the surfaces of the substrate 1.

[0052] Furthermore, the solar cell can be a solar cell as a whole part or a solar cell as a cut part. If the solar cell is a solar cell as a cut part, it has a cut side surface in the substrate 1 as a result of a cutting process. The side surfaces of the substrate 1 include the cut side surface. It is understood that the side surfaces of the substrate 1 can include both the cut side surface and other side surfaces. The common multiple pyramid body 11 can be located on a common prismatic edge c and / or a common corner d of the cut side surface and the light-receiving surface, the back side, or other adjacent side surfaces.Furthermore, after performing a cutting process on the solar cell, a post-processing process such as texturing or the like may be performed on side surfaces at cut locations to form a common multiple pyramid body 11 in zones where the cut surfaces and their adjacent surfaces are adjacent.

[0053] After cutting a complete solar cell, some damage is present at the cut side surfaces, resulting in more defect states and more dangling bonds. Therefore, there is a tendency for more severe recombination problems to occur at the cut side surfaces. By providing multiple pyramid bodies 11 at a common prismatic edge c and / or a common corner d of the cut side surface and its adjacent surfaces, problems related to more numerous defect states at the cut side surfaces due to the cutting process can be better resolved.

[0054] Furthermore, the first surface a and the second surface b are perpendicular to each other.

[0055] An explanatory description for each pyramid structure follows.

[0056] In an orthogonal projection onto the first surface a, the first pyramid structure 111 has a first diagonal with a length L1, and 0.1 µm ≤ L1 ≤ 7 µm; in a view in the direction of the orthogonal projection onto the second surface b, the second pyramid structure 112 has a second diagonal with a length L2, and 0.1 µm ≤ L2 ≤ 7 µm; and for each of the common multiple pyramid bodies 11, 0.5 ≤ L1 / L2 ≤ 2.

[0057] The length L1 of the first diagonal is an average of lengths of the diagonals on the bottom side of the first pyramid structure 111. For example, if the bottom side of the first pyramid structure 111 is a rectangle enclosing two diagonals, the length L1 of the first diagonal represents an average of the lengths of the two diagonals. For example, L1 can be 0.1 µm, 0.2 µm, 0.5 µm, 1 µm, 2 µm, 3 µm, 5 µm, or 7 µm. The length L2 of the second diagonal is an average of the lengths of the diagonals on the bottom side of the second pyramid structure 112. For example, L2 can be 0.1 µm, 0.2 µm, 0.5 µm, 1 µm, 2 µm, 3 µm, 5 µm, or 7 µm. For example, L1 / L2 can be 0.5, 0.8, 0.9, 1, 1.1, 1.2, 1.5, or 2.

[0058] When the lengths of the diagonals of the pyramid structures in both directions are within the above ranges and the ratio of the two is controlled within the above ranges, the overall size difference between one single common multiple pyramid body 11 and another is relatively small. In particular, when the ratio L1 / L2 tends to be close to 1 (e.g., when L1 / L2 is 0.8 to 1.2), it reflects better overall dimensional stability of the single common multiple pyramid body 11. This promotes, first, better light utilization and, second, subsequent deposition of functional layers, such as passivation layers, on the substrate 1 with better adhesion.

[0059] In a direction perpendicular to the first surface a, the first pyramid structure 111 has a first height H1, where 0.1 µm ≤ H1 ≤ 3 µm; in a view perpendicular to the second surface b, the second pyramid structure 112 has a second height H2, where 0.1 µm ≤ H2 ≤ 3 µm; and for each of the common multiple pyramid bodies 11, 0.5 ≤ H1 / H2 ≤ 2 applies. For example, H1 is 0.1 µm, 0.2 µm, 0.5 µm, 1 µm, 1.5 µm, 2 µm or 3 µm. For example, H2 is 0.1 µm, 0.2 µm, 0.5 µm, 1 µm, 1.5 µm, 2 µm, or 3 µm. For example, H1 / H2 is 0.5, 0.8, 0.9, 1, 1.1, 1.2, 1.5, or 2.

[0060] When the heights of the pyramid structures in both directions are within the above ranges and the ratio of the two is controlled within the above ranges, the overall height difference between one single common multiple pyramid body 11 and another is relatively small. In particular, when the ratio H1 / H2 tends to be close to 1 (e.g., when H1 / H2 is 0.8 to 1.2), it reflects better overall height uniformity of the single common multiple pyramid body 11. This better height uniformity and relatively small differences in different directions promote the quality of film formation when functional layers, such as passivation layers, are subsequently deposited on the substrate 1, and they promote a reduction in the likelihood of cracking of the functional layers due to large height differences between the common multiple pyramid bodies 11 in different directions.

[0061] Furthermore, the common multiple pyramid bodies 11 are arranged along the longitudinal direction of the common prismatic edge c. The common prismatic edge c has a central region and edge regions located on both sides of the central region. The lengths of the diagonals of the common multiple pyramid bodies 11 arranged in the central region are smaller than those of the common multiple pyramid bodies 11 arranged in the edge regions, and the heights of the common multiple pyramid bodies 11 arranged in the central region are smaller than those of the common multiple pyramid bodies 11 arranged in the edge regions.

[0062] The common multiple pyramid body 11 on the common prismatic edge c has relatively smaller sizes and heights in the center zone and relatively larger sizes and heights in the edge zone. Compared to the center zone, the edge zones of the substrate 1 are more susceptible to dirt ingestion, making cleaning problems more difficult to solve. The sizes and heights of the common multiple pyramid bodies 11 in the edge zones are relatively larger, which is more conducive to solving the dirt and contamination problems on the substrate 1 in the edge zones and therefore results in improved cleanliness.

[0063] The number of common multiple pyramid bodies 11 for the region with the length of 100 µm, which corresponds to the common prismatic edge c, is greater than or equal to 1. Preferably, the number of common multiple pyramid bodies 11 for the region with the length of 100 µm, which corresponds to the common prismatic edge c, is at least 10 and preferably 10 to 20.

[0064] Below is an explanation for the first face a and the second face b of the pyramid structure.

[0065] In addition to providing common multiple pyramid bodies 11 on the zone in which the first surface a and the second surface b are adjacent, the present application also provides a plurality of third pyramid structures 12 on the first surface a and a plurality of fourth pyramid structures 13 on the second surface b, as shown in Fig. 6 is shown.

[0066] Because the first surface a and / or the second surface b are a side surface of the substrate 1, pyramid structures are provided on this surface to contribute to increasing light absorption and utilization efficiency. Furthermore, the provision of pyramid structures on this surface can also cooperate with the common multi-pyramid body 11 to improve adhesion when multiple functional layers (such as passivation layers) are arranged on the substrate 1, so that the functional layers function more effectively.

[0067] Furthermore, the first pyramid structure 111 has a first diagonal with a length L1 in the direction of the orthogonal projection onto the first surface a, and 0.1 µm ≤ L1 ≤ 7 µm, and the third pyramid structure 12 has a third diagonal with a length L3, and 0.1 µm ≤ L3 ≤ 7 µm, 0.5 ≤ L3 / L1 ≤ 2. The length L3 of the third diagonal refers to an average length of the diagonal on the underside of the third pyramid structure 12. For example, L3 is 0.1 µm, 0.2 µm, 0.5 µm, 1 µm, 2 µm, 3 µm, 5 µm or 7 µm. For example, L3 / L1 is 0.5, 0.8, 0.9, 1, 1.1, 1.2, 1.5, or 2.

[0068] The second pyramid structure 112 has, in the orthogonal projection of the second surface b, a second diagonal with a length L2, and 0.1 µm ≤ L2 ≤ 7 µm, and the fourth pyramid structure 13 has a fourth diagonal with a length L4, and 0.1 µm ≤ L4 ≤ 7 µm, 0.5 ≤ L4 / L2 ≤ 2. The term “length L4 of the fourth diagonal” refers to the mean value of the lengths of the diagonals on the underside of the fourth pyramid structure 13. For example, L4 is 0.1 µm, 0.2 µm, 0.5 µm, 1 µm, 2 µm, 3 µm, 5 µm or 7 µm. For example, L4 / L2 is 0.5, 0.8, 0.9, 1, 1.1, 1.2, 1.5, or 2.

[0069] When the diagonal lengths of the first pyramid structure 111 and the third pyramid structure 12 are within the above range and ratio, and the diagonal lengths of the second pyramid structure 112 and the fourth pyramid structure 13 are within the above range and ratio, the differences between the overall dimensions of these pyramid structures on the first surface a, the second surface b, and the zones where the first surface a and the second surface b are adjacent are relatively smaller, reflecting better uniformity of the overall dimensions of the pyramid structures at different positions. This can reduce problems of numerous defects of pits between pyramid structures due to large size differences, thereby reducing the risks of numerous defects and increased contamination with impurities.

[0070] Furthermore, the first pyramid structure 111 has a first height H1 in a direction perpendicular to the first surface a, and 0.1 µm ≤ H1 ≤ 3 µm, and the third pyramid structure 12 has a third height H3, and 0.1 µm ≤ H3 ≤ 5 µm, 0.5 ≤ H3 / H1 ≤ 2. For example, H3 is 0.1 µm, 0.5 µm, 1 µm, 1.5 µm, 2 µm, 3 µm, 4 µm, or 5 µm. For example, H3 / H1 is 0.5, 0.8, 0.9, 1, 1.1, 1.2, 1.5, or 2.

[0071] The second pyramid structure 112 has a second height H2 in a direction perpendicular to the second surface b, and 0.1 µm ≤ H2 ≤ 3 µm, and the fourth pyramid structure 13 has a fourth height H4, and 0.1 µm ≤ H4 ≤ 5 µm, 0.5 ≤ H4 / H2 ≤ 2. For example, H4 is 0.1 µm, 0.5 µm, 1 µm, 1.5 µm, 2 µm, 3 µm, 4 µm, or 5 µm. For example, H4 / H2 is 0.5, 0.8, 0.9, 1, 1.1, 1.2, 1.5, or 2.

[0072] When the heights of the first pyramid structure 111 and the third pyramid structure 12 are in the above ranges and ratios, and the heights of the second pyramid structure 112 and the fourth pyramid structure 13 are in the above ranges and ratios, the differences between the total heights of these pyramid structures on the first surface a, the second surface b, and the zones where the first surface a and the second surface b are adjacent are relatively smaller, which reflects better uniformity of the total heights of the pyramid structures at different positions.

[0073] Below is an explanation of other structures of the solar cell in the embodiments of the present application.

[0074] The solar cell of the present embodiments further comprises: a semiconductor layer arranged on the light-receiving surface and / or the back side of the substrate 1; a passivation layer arranged on a surface of the semiconductor layer facing away from the substrate 1 and arranged on the side surface of the substrate 1, and an electrode.

[0075] Of these, the electrode can penetrate the passivation layer and form an ohmic contact with the semiconductor layer.

[0076] As an alternative embodiment, which is Fig. As shown in Figure 7, the solar cell is a back-contact solar cell. The solar cell comprises: the substrate 1; a first semiconductor layer 21 and a first electrode 31 provided successively in a P-type conductive region on the back side of the substrate 1; and a second semiconductor layer 22 and a second electrode 32 provided sequentially in an N-type conductive region on the back side of the substrate 1; wherein the first semiconductor layer 21 and the second semiconductor layer 22 are arranged alternately in an interlocking manner and an insulation region 4 is present between the first semiconductor layer 21 and the second semiconductor layer 22.

[0077] The solar cell also includes: a first passivation layer 51 provided on a surface of the first semiconductor layer 21 facing away from the substrate; a second passivation layer 52 provided on a surface of the second semiconductor layer 22 facing away from the substrate; a third passivation layer 53 provided on the light-receiving surface of the substrate 1; and a fourth passivation layer 54 provided on the side surface of the substrate 1.

[0078] It should be understood that the first passivation layer 51 and the second passivation layer 52 may be provided on the first semiconductor layer 21 and the second semiconductor layer 22, respectively, because both the first semiconductor layer 21 and the second semiconductor layer 22 are provided on the backside of the substrate 1. Alternatively, the first passivation layer 51 and the second passivation layer 52 may be provided as a complete passivation layer on the entire backside, covering the first semiconductor layer 21 and the second semiconductor layer 22 as well as the isolation region 4 on the substrate 1.

[0079] Because the common prismatic edges c and / or the common corners d of the light-receiving surface and the side surface of the substrate 1 have the above-described common multiple pyramid bodies 11 with common surfaces and third pyramid structures 12 are provided on the side surfaces, an improvement of adhesion results of the fourth passivation layer 54 provided on the side surfaces of the substrate 1 is facilitated, which in turn enhances the passivation performance of the fourth passivation layer 54.

[0080] Furthermore, a first dielectric layer 61 is provided between the substrate 1 and the first semiconductor layer 21 and a second dielectric layer 62 is provided between the substrate 1 and the second semiconductor layer 22.

[0081] Optionally, the first semiconductor layer 21 is a first doped layer of polycrystalline silicon or a first doped layer of amorphous silicon deposited on the backside of the substrate 1. The second semiconductor layer 22 is a second doped layer of polycrystalline silicon or a second doped layer of amorphous silicon deposited on the second dielectric layer.

[0082] Optionally, the first passivation layer 51 is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer. The second passivation layer 52 is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer. The third passivation layer 53 is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer. The fourth passivation layer 54 is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer.

[0083] Optionally, the first dielectric layer 61 is a silicon oxide layer, a layer of amorphous silicon, a layer of polycrystalline silicon, and / or a silicon nitride layer. The second dielectric layer 62 is a silicon oxide layer, a layer of amorphous silicon, a layer of polycrystalline silicon, and / or a silicon nitride layer.

[0084] As an alternative embodiment, the solar cell is a solar cell with passivated contacts. The solar cell comprises: the substrate 1; a first semiconductor layer 21 and a first electrode 31 provided sequentially on the light-receiving surface of substrate 1, wherein the first semiconductor layer 21 and the substrate 1 each have different conductivity types; and a dielectric layer, a second semiconductor layer 22 and a second electrode 32, which are provided successively on the back side of substrate 1.

[0085] Of these, the first electrode 31 is in ohmic contact with the first semiconductor layer 21, and the second electrode 32 is in ohmic contact with the second semiconductor layer 22.

[0086] The solar cell also includes: a fifth passivation layer provided on a surface 21 of the first semiconductor layer facing away from the substrate; a sixth passivation layer provided on a side surface of the second semiconductor layer 22 facing away from the substrate; and a seventh passivation layer provided on the side of substrate 1.

[0087] Because the common prismatic edges c and / or the common corners d of the light-receiving surface (or back surface) and the side surface of the substrate 1 have the above-described common multiple pyramid bodies 11 having common surfaces and third pyramid structures 12 are provided on the side surfaces, improvement of adhesion results of the seventh passivation layer provided on the side surfaces of the substrate 1 is facilitated, which in turn enhances the passivation performance of the seventh passivation layer.

[0088] Optionally, the first semiconductor layer 21 is formed by thermal diffusion of doping elements into the substrate 1, or the first semiconductor layer 21 is a first doped layer of polycrystalline silicon or a first doped layer of amorphous silicon deposited on the backside of the substrate 1. The second semiconductor layer 22 is a second doped layer of polycrystalline silicon or a second doped layer of amorphous silicon deposited on the second dielectric layer.

[0089] Optionally, the fifth passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer. The sixth passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer. The seventh passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer.

[0090] Optionally, the dielectric layer is a silicon oxide layer, a layer of amorphous silicon, a layer of polycrystalline silicon and / or a silicon carbide layer.

[0091] In the present embodiment of the present application, a method for manufacturing the above-mentioned solar cell is also provided. It is understood that the solar cell of the embodiments of the present application can also be obtained by other manufacturing methods and is not limited by the present application.

[0092] As an example, the fabrication of a solar cell with back contacts using the substrate described above is described as follows. In the embodiments of the present application, a method for fabricating a solar cell with back contacts is provided, comprising the following steps: A first polishing step: a mixed solution of alkali and additives is used to pretreat the silicon substrate and remove scratches and oil contamination from surfaces. The alkali solution contains NaOH or KOH at a concentration of 0.6 to 4.8 wt% and additives at a concentration of 0.9 to 1.1 wt%. The polishing temperature is 50 to 90°C, and the polishing time is 400 to 900 seconds. After polishing, a mixed solution of hydrofluoric acid and hydrochloric acid is used for deep cleaning, followed by thorough rinsing with deionized water and finally drying. a first coating:

[0093] LPCVD is used to sequentially deposit a silicon oxide layer with a thickness of 0.6 nm to 2.8 nm as the first dielectric layer and a layer of intrinsically amorphous silicon with a thickness of 120 nm to 280 nm on the backside of a silicon substrate at a deposition temperature of 540 °C to 660 °C. Preferably, a 2 nm silicon oxide layer and a 250 nm intrinsically amorphous silicon layer are deposited; by doping the intrinsically amorphous silicon layer using a thermal diffusion method, thereby converting the intrinsically amorphous silicon layer into the first doped crystalline silicon layer. The doping type is opposite to that of the silicon substrate. For example, if the silicon substrate is an N-type silicon substrate, a boron source is doped into the intrinsically amorphous silicon layer using a thermal diffusion method to obtain the boron-doped crystalline silicon layer as the first doped crystalline silicon layer. After doping is completed, a first doped silicon oxide mask layer is formed on a surface of the first doped crystalline silicon layer, and the thickness of the first doped silicon oxide mask is 18-62 nm; a first pattern formation: on one side of the back side of the silicon substrate, wherein the first mask of doped silicon oxide is opened by laser etching until the first layer of doped crystalline silicon is exposed and a patterned first mask of doped silicon oxide is obtained; wherein the conditions for the laser etching include: (1) the laser type, which includes at least nanoseconds, picoseconds and / or femtoseconds; (2) the wavelength of the laser, which can be selected from an infrared laser, visible light emitting laser or ultraviolet laser; (3) the laser energy, which can be within 30-3000 mJ / cm 2 controlled; (4) the wavelength range, which can be between 700-1000 nm; (5) the shape of the laser spot, including circular, square, rectangular, or elliptical; A second polishing step: an alkaline solution is used to etch and remove the first layer of doped crystalline silicon and the first dielectric layer, corresponding to a laser-irradiated zone, until the silicon substrate is exposed (underlying film layers are protected during this process due to the protection of the patterned mask of doped silicon oxide). The alkaline solution contains NaOH or KOH at a concentration of 0.5 wt% to 5 wt% and additives at a concentration of 0.9 wt% to 1.1 wt%, consisting mainly of sodium gluconate, protectants, and brighteners. The process temperature is 65–85°C, and the polishing time is 300–800 seconds.After the second polishing is completed, alkaline washing with an alkaline solution and water washing are carried out in sequence, and then acid washing with an acid solution, water washing and drying are carried out.

[0094] A second coating: A PECVD process is used to sequentially deposit a second dielectric layer with a thickness of 1.5 nm, a second layer of doped amorphous silicon with a thickness of 200 nm, and a second mask of doped silicon oxide on one side of the back surface. Annealing is performed to convert the second layer of doped amorphous silicon into the second layer of doped polycrystalline silicon, with the second mask of doped silicon oxide having a thickness of 20 nm to 60 nm.

[0095] A second pattern formation: on one side of the back surface, a large portion of the second mask of doped silicon is removed by laser etching (wherein a removed zone includes: a zone corresponding to the first layer of doped crystalline silicon and a zone used to form a trench zone) to expose the second layer of doped polycrystalline silicon; where laser etching conditions include: (1) the laser type, which includes at least nanoseconds, picoseconds, and / or femtoseconds; and (2) the wavelength of the laser, which can be selected from an infrared laser, visible light emitting laser, or ultraviolet laser; (3) the laser energy, which can be within 30-3000 mJ / cm 2 controlled; (4) the wavelength range, which can be between 700-1000 nm; and (5) the shape of the laser spot, which is (20-400) µm × (20-400) µm.

[0096] Acid polishing and texturing: The light-receiving surface is polished with acid; a chain-type machine is used as the acid polishing station; a mixed acid solution of hydrofluoric acid, nitric acid, and sulfuric acid is used to corrode and remove the mask layer on the light-receiving surface. At the same time, due to the adsorbing capillary action during the acid polishing process, the rising chemical solution also reacts with and corrodes the mask layer. Therefore, acid polishing removes all coating layers and doped silicon oxide masks on the light-receiving surface and side surfaces, exposing the substrate of the light-receiving surface and side surfaces.During this process, a water film is sprayed on the back before acid polishing to protect the film layers on the back and ensure that the back is not corroded during the acid polishing process of the light-receiving surface and side surfaces. Texturing: wherein, during the texturing process, due to differences in the corrosion rate by an alkaline solution between the surface (100) and the surface (111) of a silicon wafer, a third pyramid structure and a fourth pyramid structure are formed on the side surface and the light-receiving surface, respectively, and a common multiple pyramid body is formed in the zone where the light-receiving surface and the side surface are adjacent, wherein an alkaline solution and texturing additives are used for texturing. The alkaline solution is KOH or NaOH, and its concentration is controlled within a range of 1-5 wt%. The concentration of texturing additives is 0.5-2 wt%, and its main components include carboxymethyl cellulose, sodium lignosulfate, a defoamer, and so on. In the texturing additives, 1 wt% carboxymethyl cellulose, 1 wt%-% sodium lignosulfonate and 0.5 wt.% defoamer. The texturing temperature is set at 60-85 °C, and the texturing time is 300-800 seconds.

[0097] Alkaline washing, water washing, acid washing, water washing, and drying: After texturing is complete, alkaline washing is performed using a mixed solution of KOH and H2O2 or NaOH and H2O2 to remove residual additive substances from the texturing process. Then, the silicon wafers are washed. Acid washing removes the first mask of doped silicon oxide and the second mask of doped silicon oxide on the backside using an HF solution. A third coating: PECVD is used to deposit a 4 nm thick aluminum oxide layer on the light-receiving surface, side surfaces, and back surface. Then, silicon nitride layers are deposited separately to create passivation and reflection reduction effects; the silicon nitride layer on the light-receiving surface is 75 nm, the silicon nitride layer on the back surface is 92 nm, and the silicon nitride layer on the side surface is 167 nm. screen printing and sintering to form electrodes.

[0098] In the solar cell obtained by the above method, the light-receiving surface of the substrate has a plurality of fourth pyramidal structures, the side surfaces have a plurality of third pyramidal structures, and the common prismatic edges have a plurality of common multi-pyramidal bodies, with the light-receiving surface and the side surfaces being adjacent. In connection with scanning electron microscopy images in Fig. 8 and Fig. 9, the common multiple pyramid bodies are shown, especially those in a view from angles towards the cut side surface. The scanning electron micrographs in the Fig. 8 and Fig. 9 are obtained with a scanning electron microscope from ZEISS (Zeiss, Germany). Observation conditions in Fig.8 include an accelerating voltage of 15.00 kV in InLens mode, a working distance of 6.8 mm, and a magnification of 5.00 KX. Observation conditions in Fig. 9 include an accelerating voltage of 15.00 kV in InLens mode, a working distance of 11.7 mm, and a magnification of 10.00 KX.

[0099] Furthermore, in the manufacturing method of the embodiments of the present application, cutting a semi-finished solar cell may be performed before the texturing step, and then texturing and subsequent operations may be performed after cutting. For example, in the context of the previously introduced manufacturing method, cutting may be performed after acid polishing the light-receiving surface and before texturing. Cutting may also be performed after the second patterning step and before the acid polishing step of the light-receiving surface. By cutting the semi-finished solar cell, at least one side surface of the substrate may become a cut side.In a finished solar cell, common multiple pyramid bodies are arranged where the light-receiving surface and the side surface are adjacent; further, common multiple pyramid bodies are arranged on the common prismatic edges where the side surfaces are adjacent; and common triple pyramid bodies are arranged on the common corners where the light-receiving surface and two side surfaces are adjacent.

[0100] In a second aspect, embodiments of the present application also provide a photovoltaic module comprising the solar cell described in the first aspect.

[0101] An explanation is provided below, along with more specific examples and experimental data. Embodiment 1

[0102] In this embodiment, a solar cell is provided comprising: an N-type silicon substrate; a first dielectric layer, a first semiconductor layer, and a first electrode arranged sequentially on a -type conductive region of the back surface of the substrate; wherein the first semiconductor layer is a boron-doped polycrystalline silicon layer; a second dielectric layer, a second semiconductor layer, and a second electrode arranged sequentially on a P-type conductive region of the back surface of the substrate; wherein the second semiconductor layer is a phosphorus-doped polycrystalline silicon layer; wherein the first semiconductor layer and the second semiconductor layer are arranged alternately in an interlocking manner and an insulation region is present between the first semiconductor layer and the second semiconductor layer; a first passivation layer provided on a surface of the first semiconductor layer facing away from the substrate; a second passivation layer provided on a surface of the second semiconductor layer facing away from the substrate; wherein the first passivation layer and the second passivation layer belong to a structure of a whole layer, the first electrode penetrates the first passivation layer and forms an ohmic contact with the first semiconductor layer, and the second electrode penetrates the second passivation layer and forms an ohmic contact with the second semiconductor layer; a third passivation layer provided on the light-receiving surface of the substrate; a fourth passivation layer provided on the side surfaces of the substrate.

[0103] In this case, the substrate is provided with a plurality of third pyramid structures on the side surfaces and a plurality of fourth pyramid structures on the light-receiving surfaces in addition to light-receiving surfaces and side surfaces; and furthermore, common multiple pyramid bodies with common surfaces are provided on the common prismatic edge at which the light-receiving surfaces and the side surfaces are adjacent.

[0104] When viewed toward a side surface, the common multiple pyramid body includes a first pyramid structure enclosed by a plurality of first triangular faces and a plurality of third triangular faces. When viewed toward the light-receiving surface, the common multiple pyramid body includes a second pyramid structure enclosed by a plurality of second triangular faces and a plurality of third triangular faces, the third triangular face being a common face, and triangular faces in the first triangular face, the second triangular face, and the third triangular face having the shape of a triangle or quasi-triangle.

[0105] In an orthogonal projection of a side surface, the first pyramid structure has a first diagonal with length L1 in the orthogonal projection of the light-receiving surface, ranging from 0.1 µm to 7 µm, the second pyramid structure has a second diagonal with length L2, ranging from 0.1 µm - 7 µm, and for each of the common multiple pyramid bodies, 0.5 ≤ L1 / L2 ≤ 2.

[0106] The first pyramid structure has a first height H1 in a direction perpendicular to the side surface, which ranges from 0.1 µm to 3 µm; the second pyramid structure has a second height H2 in a direction perpendicular to the light-receiving surface, which ranges from 0.1 µm to 3 µm; and for each of the common multiple pyramid bodies, 0.5 ≤ H1 / H2 ≤ 2 applies.

[0107] The number of common multiple pyramid bodies for the region with a length of 100 µm, which corresponds to the common prismatic edge, is greater than or equal to one.

[0108] In an orthogonal projection of the side surface, the third pyramid structure has a diagonal with a length L3 ranging from 0.1 µm - 7 µm, and 0.5 ≤ L3 / L1 ≤ 2. In an orthogonal projection of the light-receiving surface, the fourth pyramid structure has a fourth diagonal with a length L4 ranging from 0.1 µm - 7 µm, and 0.5 ≤ L4 / L2 ≤ 2.

[0109] The third pyramid structure has a third height H3 in a direction perpendicular to the side surface, which ranges from 0.1 µm to 3 µm, and 0.5 ≤ H3 / H1 ≤ 2. The fourth pyramid structure has a fourth height H4 in a direction perpendicular to the light-receiving surface, which ranges from 0.1 µm to 3 µm, and 0.5 ≤ H4 / H2 ≤ 2. Embodiment 2

[0110] The differences between this embodiment and Embodiment 1 are that the solar cell is a cut-piece solar cell and that a cut side surface is formed at the cut points.

[0111] In addition to the common double pyramid bodies having common surfaces provided on the common prismatic edges where the cut side surfaces and the light-receiving surfaces are adjacent, on the common prismatic edges where the cut side surface and the other side surfaces are adjacent, and on the substrate, the common triple pyramid bodies are further provided on the common prismatic corner of the three surfaces of the cut side surface, the light-receiving surface and the side surface adjacent to the cut side surface and on the substrate. Comparison example 1

[0112] The difference between this comparative example and Embodiment 1 is only that the light-receiving surface of the solar cell has a fourth pyramid structure, and the side surface does not have a third pyramid structure and a common multiple pyramid body. Comparison example 2

[0113] The difference between this comparative example and Embodiment 1 is only that the side surface of the solar cell has a third pyramid structure and the light-receiving surface of the solar cell has a fourth pyramid structure without a common multiple pyramid body. Performance tests

[0114] A Halm testing and sorting device was used to conduct performance tests on open-circuit voltage, fill factor, photoelectric efficiency, and other aspects. Halm machines are devices that simulate sunlight and are equipped with electronic loads, data acquisition, and calculation devices for testing the electrical performance of photovoltaic devices (including solar cells). The calibrated light intensity of the solar cell used to control the test is 1000 ± 5 W / m 2 .

[0115] Test results are shown in Table 1 below. Table 1 - Test results of embodiments 1 to 2 and comparative examples 1 to 2 Open circuit voltage (V) Fill factor (%) Short-circuit current (A) Photoelectric efficiency (%) Embodiment 1 0,7346 81,98 8,228 25,84 Embodiment 2 0,7367 81,72 8,243 25,87 Comparison example 1 0,7353 81,43 8,234 25,71 Comparison example 2 0,7355 81,34 8,213 25,72

[0116] Comparing the test results of Embodiment 1 with Comparative Examples 1 and 2, it can be seen that when pyramid structures are provided on adjacent surfaces of the substrate and common multiple pyramid bodies with common surfaces are provided on the common prismatic edges of the adjacent surfaces, the photoelectric efficiency of the solar cell is improved by more than 0.1%. In the field of solar cells, the effect of an improvement of more than 0.1% means that higher practical significance is obtained when solar cells are assembled into photovoltaic modules for application. As a result, the solar cell of the present embodiment promotes further improvement in cell performance due to the presence of common multiple pyramid bodies.

[0117] Furthermore, comparing Embodiment 1 and Embodiment 2, it can be seen that after cutting the cells, the common multiple pyramid bodies formed at the cut positions include both common double pyramid bodies and common triple pyramid bodies. These structural features are advantageous for further improving the performance of the solar cells.

[0118] The above provides a detailed introduction to the technical solutions disclosed in the embodiments of this application. Specific examples are used here to explain the principles and implementation methods of this application. The above description of the embodiments is intended only to assist in understanding the technical solution and basic inventive points of this application. At the same time, changes to the embodiments and the scope of application may be made by a person skilled in the art based on ideas from this application. Therefore, the content of this application should not be construed as limiting this application.

Claims

[1] Solar cell comprising: a substrate having a first surface and a second surface adjacent to each other on the substrate, at least one of which is a side surface of the substrate; wherein the substrate further comprises a common multiple pyramid body having a common surface on common prismatic edges and / or common corners where the first surface and the second surface are adjacent; wherein the common multiple pyramid body, when viewed in the direction of the first surface, comprises a first pyramid structure formed by enclosing a plurality of first triangular surfaces and a plurality of third triangular surfaces, and wherein the common multiple pyramid body, when viewed in the direction of the second surface, comprises a second pyramid structure formed by enclosing a plurality of second triangular surfaces and a plurality of third triangular surfaces, and wherein the third triangular surface is the common surface and the triangular surfaces in the first triangular surface, the second triangular surface and the third triangular surface have the shape of a triangle or a quasi-triangle. [2] The solar cell according to claim 1, wherein the common multi-pyramidal body is a common double-pyramidal body, and wherein the first surface is a first side surface of the substrate, the second surface includes a first bottom surface which is any one of a light-receiving surface, a back surface, and a second side surface of the substrate, and the common double-pyramidal body is provided on the common prismatic edge in a region where the first surface and the first bottom surface are adjacent; or wherein the common multiple pyramid body is a common triple pyramid body, and wherein the first surface is a first side surface of the substrate, the second surface includes a first bottom surface and a second bottom surface, the first bottom surface is a light-receiving surface or a back surface of the substrate, the second bottom surface is a second side surface adjacent to the first side surface, and the common triple pyramid body is provided on the common corner in a zone where the first surface, the first bottom surface, and the second bottom surface are adjacent. [3] The solar cell of claim 1, wherein the solar cell is a disc cell, the substrate has a cut side surface, and the side surface of the substrate includes the cut side surface, and / or the first surface and the second surface are perpendicular to each other. [4] The solar cell according to claim 1, wherein, in an orthogonal projection of the first surface, the first pyramid structure has a first diagonal with a length L1, and 0.1 µm ≤ L1 ≤ 7 µm; the second pyramid structure has a second diagonal with a length L2 in an orthogonal projection of the second surface, and 0.1 µm ≤ L2 ≤ 7 µm, and for each of the common multiple pyramid bodies L1 and L2 satisfy 0.5 ≤ L1 / L2 ≤ 2; or wherein in a direction perpendicular to the first surface, the first pyramid structure has a first height H1, and 0.1 µm ≤ H1 ≤ 3 µm; in a direction perpendicular to the second surface, the second pyramid structure has a second height H2, and 0.1 µm ≤ H2 ≤ 3 µm, and for each of the common multiple pyramid bodies H1 and H2 satisfy 0.5 ≤ H1 / H2 ≤ 2. [5] The solar cell according to claim 1, wherein the common multiple pyramid body is arranged along a longitudinal direction of the common prismatic edge and wherein the common prismatic edge has a central region and edge regions arranged on both sides of the central region; wherein the length of the diagonal of the common multiple pyramid body arranged in the central region is smaller than that of the diagonal of the common multiple pyramid body arranged in the edge regions; the height of the common multiple pyramid body arranged in the central region is smaller than that of the common multiple pyramid body arranged in the edge regions and / or the number of common multiple pyramid bodies for a region of length 100 µm corresponding to the common prismatic edge c is greater than or equal to 1; where appropriate, the number of common multiple pyramid bodies for the region with a length of 100 µm corresponding to the common prismatic edge is at least 10. [6] A solar cell according to any one of claims 1 to 5, wherein a plurality of third pyramid structures are provided on the first surface and a plurality of fourth pyramid structures are provided on the second surface; wherein, optionally, the first pyramid structure has, in an orthogonal projection of the first surface, a first diagonal with a length L1, where 0.1 µm ≤ L1 ≤ 7 µm, and the third pyramid structure has a third diagonal with a length L3, where 0.1 µm ≤ L3 ≤ 7 µm, and 0.5 ≤ L3 / L1 ≤ 2; and wherein the second pyramid structure has, in an orthogonal projection of the second surface, a second diagonal with a length L2, where 0.1 µm ≤ L2 ≤ 7 µm, and the fourth pyramid structure has a fourth diagonal with a length L4, where 0.1 µm ≤ L4 ≤ 7 µm and 0.5 ≤ L4 / L2 ≤ 2; wherein optionally the first pyramid structure has a first height H1 in a direction perpendicular to the first surface, where 0.1 µm ≤ H1 ≤ 3 µm, and the third pyramid structure has a third height H3, where 0.1 µm ≤ H3 ≤ 5 µm and 0.5 ≤ H3 / H1 ≤ 2; and wherein the second pyramid structure has a second height H2 in a direction perpendicular to the second surface, where 0.1 µm ≤ H2 ≤ 3 µm, and the fourth pyramid structure has a fourth height H4, where 0.1 µm ≤ H4 ≤ 5 µm and 0.5 ≤ H4 / H2 ≤ 2. [7] A solar cell according to any one of claims 1 to 6, wherein the solar cell further comprises: a semiconductor layer disposed on a light-receiving surface and / or a back surface of the substrate; a passivation layer arranged on a surface of the semiconductor layer facing away from the substrate and arranged on the side surface of the substrate, and an electrode; wherein the solar cell optionally comprises: the substrate; a first semiconductor layer and a first electrode provided sequentially in a P-type conductive region on the back side of the substrate; and a second semiconductor layer and a second electrode provided successively in an N-type conductive region on the back of the substrate, wherein the first semiconductor layer and the second semiconductor layer are arranged alternately in an interlocking manner and an insulation region is present between the first semiconductor layer and the second semiconductor layer; wherein the solar cell may further comprise: a first passivation layer provided on a surface of the first semiconductor layer facing away from the substrate; a second passivation layer provided on a surface of the second semiconductor layer facing away from the substrate; a third passivation layer provided on the light-receiving surface of the substrate; and a fourth passivation layer provided on the side surface of the substrate; wherein optionally a first dielectric layer is further provided between the substrate and the first semiconductor layer and a second dielectric layer is further provided between the substrate and the second semiconductor layer. [8] The solar cell of claim 7, wherein the first semiconductor layer is a first layer of doped polycrystalline silicon or a first layer of doped amorphous silicon deposited on the backside of the substrate, and the second semiconductor layer is a second layer of doped polycrystalline silicon or a second layer of doped amorphous silicon deposited on the second dielectric layer; and / or wherein the first passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer, the second passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer, the third passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer, and the fourth passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer; and / or wherein the first dielectric layer is a silicon oxide layer, a layer of amorphous silicon, a layer of polycrystalline silicon and / or a silicon nitride layer and the second dielectric layer is a silicon oxide layer, a layer of amorphous silicon, a layer of polycrystalline silicon and / or a silicon nitride layer. [9] A solar cell according to claim 7, wherein the solar cell comprises: the substrate; a first semiconductor layer and a first electrode provided sequentially on the light-receiving surface of the substrate, wherein the first semiconductor layer and the substrate have different conductivity types; and a dielectric layer, a second semiconductor layer and a second electrode provided sequentially on the back side of the substrate; wherein the solar cell may further comprise: a fifth passivation layer provided on a surface of the first semiconductor layer facing away from the substrate; a sixth passivation layer provided on a surface of the second semiconductor layer facing away from the substrate; and a seventh passivation layer provided on the side surface of the substrate; wherein optionally the first semiconductor layer is formed by thermal diffusion of doped elements into the substrate or the first semiconductor layer is a first layer of doped polycrystalline silicon or a first layer of doped amorphous silicon deposited on the back side of the substrate, and the second semiconductor layer is a second layer of doped polycrystalline silicon or a second layer of doped amorphous silicon deposited on the second dielectric layer; and / or wherein the fifth passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer, the sixth passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer, and the seventh passivation layer is one or more layers of an aluminum oxide layer, silicon oxide layer, silicon oxynitride layer, or silicon nitride layer; and / or wherein the dielectric layer is a silicon oxide layer, a layer of amorphous silicon, a layer of polycrystalline silicon, and / or a silicon carbide layer. [10] A photovoltaic module, wherein the photovoltaic module comprises a solar cell according to any one of claims 1-9.

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