Solar cell and photovoltaic module

Abstract

The utility model discloses a solar cell and a photovoltaic module, the solar cell comprises a half cell and a section passivation layer, the side wall of the half cell is provided with at least one section along the circumferential direction of the solar cell, the section passivation layer covers the section, and the section passivation layer covers the section along the length direction and / or the width direction of the solar cell. And the thickness H of the section passivation layer is more than or equal to 15nm and less than or equal to 100nm, so that the section is passivated through the section passivation layer covering the half cell section, the interface state defect density at the section is reduced, the dangling bond is saturated, and the possibility that the dangling bond becomes a recombination center is reduced. Fixed charges can be introduced into the section passivation layer to form a built-in electric field, so that recombination of carriers is further inhibited, and the overall photoelectric conversion efficiency of the battery piece is improved. In addition, the section passivation layer can protect the section so as to reduce the possibility that the working performance of the half cell is affected by environmental factors such as moisture on the section, and the stability and the reliability of the cell in the working process are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a solar cell and a photovoltaic module. BACKGROUND

[0002] At present, in order to avoid the problems of low module power and hot spot caused by the difference in electrical performance of solar cells, the half-piece, shingle and overlap welding module technologies are gradually adopted to reduce or even eliminate the inter-string spacing in the cell string, increase the effective area, reduce the current in the cell string circuit, and thus reduce the circuit transmission loss.

[0003] Among them, the half-piece photovoltaic module and the shingle photovoltaic module need to cut the solar cell in the manufacturing process to cut the complete square solar cell into multiple small solar cells, and then connect each small solar cell to each other by inter-string interconnection technology to form a cell string, and then perform a series of subsequent module production and manufacturing processes such as string arrangement, detection, lamination and frame installation.

[0004] In the prior art, laser cutting technology is usually used to cut the complete solar cell to form small solar cells, but due to mechanical damage and cutting surface suspension in the cutting process, it is easy to cause the photoelectric conversion efficiency of the cut solar cell to be reduced, thereby causing the overall working performance of the photovoltaic module to be reduced. CONTENT OF THE UTILITY MODEL

[0005] Therefore, the present application provides a solar cell and a photovoltaic module to solve the technical problem of reduced photoelectric conversion efficiency of the solar cell after being cut in the prior art.

[0006] The present application provides a solar cell, which comprises a half-piece cell and a cross-section passivation layer, the side wall of the half-piece cell has at least one cross-section along the circumference of the solar cell, and the cross-section passivation layer covers the cross-section, wherein the thickness of the cross-section passivation layer is H along the length direction and / or the width direction of the solar cell, and H satisfies 15nm≤H≤100nm.

[0007] In the embodiments of the present application, by setting the cross-section passivation layer and covering it on the cross-section of the half-cell, the cross-section can be passivated to reduce the interface state defect density at the cross-section and saturate the dangling bonds, thereby reducing the possibility of dangling bonds becoming recombination centers. Moreover, the cross-section passivation layer can also introduce fixed charges for forming an internal electric field on the contact surface with the cross-section, thereby being able to further inhibit the recombination of carriers and improve the overall photoelectric conversion efficiency of the cell piece. At the same time, the cross-section passivation layer can also protect the cross-section to reduce the possibility of the cross-section being affected by environmental factors such as moisture to affect the working performance of the half-cell, which is conducive to improving the stability and reliability of the cell piece during working.

[0008] In a possible implementation, along the length direction and / or the width direction of the solar cell piece, the cross-section passivation layer has a first contact surface on the side facing the cross-section, the defect state density of the first contact surface is D, and D satisfies D < 10 8 ev -1 cm -2 .

[0009] In a possible implementation, along the length direction and / or the width direction of the solar cell piece, the cross-section passivation layer at least includes a first cross-section passivation layer and a second cross-section passivation layer, the first cross-section passivation layer covers the cross-section, and the second cross-section passivation layer covers the side of the first cross-section passivation layer away from the cross-section, wherein the first cross-section passivation layer includes silicon oxide, and the second cross-section passivation layer includes metal oxide.

[0010] In a possible implementation, the cross-section passivation layer further includes a third cross-section passivation layer, the third cross-section passivation layer is located between the first cross-section passivation layer and the second cross-section passivation layer, the first cross-section passivation layer and the third cross-section passivation layer both have silicon elements, and the third cross-section passivation layer and the second cross-section passivation layer have the same metal element.

[0011] In a possible implementation, the thickness of the first cross-section passivation layer is h1, the thickness of the second cross-section passivation layer is h2, and the thickness of the third cross-section passivation layer is h3, and h1, h2 and h3 satisfy h1 < h3 < h2, h1 satisfies 5 nm ≤ h1 ≤ 6 nm, h2 satisfies 60 nm < h2 ≤ 70 nm, and h3 satisfies 15 nm < h3 ≤ 30 nm.

[0012] In one possible implementation, the first cross-sectional passivation layer is a SiOx layer with a fixed charge density of Qf1, the second cross-sectional passivation layer is a SiAlOx layer with a fixed charge density of Qf2, and the third cross-sectional passivation layer is an AlOx layer with a fixed charge density of Qf3, wherein Qf1, Qf2, and Qf3 satisfy Qf1 < Qf3 < Qf2, and Qf1 satisfies Qf1 < 10¹² cm⁻¹. -2 Qf2 satisfies 10 14 cm -2 <Qf2, Qf3 satisfy 10 12 cm -2 <Qf3<10 14 cm -2 .

[0013] In one possible implementation, the half-cell includes a substrate. Along the thickness direction of the solar cell, the substrate has a front side and a back side disposed opposite to each other. The angle between the cross-section and the front side is a first angle, and the angle between the cross-section and the back side is a second angle. The first angle and the second angle are complementary angles. The first angle is α, the second angle is β, and α satisfies 85° < α ≤ 90°, or β satisfies 85° < β ≤ 90°.

[0014] In one possible implementation, the front side is covered with a first passivation layer, the back side is covered with a second passivation layer, and along the length and width directions of the solar cell, the cross-sectional passivation layer covers at least the side of the first passivation layer, the substrate, and the second passivation layer on the side facing the cross-section, wherein the cross-sectional passivation layer is made of the same material as at least one of the first passivation layer and the second passivation layer.

[0015] In one possible implementation, the cross-sectional passivation layer extends along the thickness direction of the solar cell, one end of the cross-sectional passivation layer covers at least a portion of the first passivation layer, and / or, the other end of the cross-sectional passivation layer covers at least a portion of the second passivation layer.

[0016] This application also provides a photovoltaic module, the photovoltaic module including a cover plate, an encapsulating film and a battery string, the battery string including a plurality of solar cells, the solar cells being any of the solar cells described above, wherein, along the thickness direction of the solar cells, the encapsulating film covers one side of the battery string, and the cover plate covers the side of the encapsulating film opposite to the battery string.

[0017] In the embodiments of the present application, the photovoltaic module can include a plurality of cell strings, the plurality of cell strings are electrically connected in series and / or in parallel, and each cell string includes the above-mentioned half-cell, and the power loss of each cell string during operation can be improved by covering the cross-section passivation layer on the cross-section of each half-cell, thereby facilitating to improve the photoelectric conversion efficiency of the photovoltaic module as a whole.

[0018] It should be understood that the above general description and the following detailed description are only exemplary and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 is a structural schematic diagram of the half-cell provided by the present application in an embodiment;

[0021] Figure 2 is a structural schematic diagram of the half-cell provided by the present application in another embodiment.

[0022] Explanation of reference signs:

[0023] 1-half-cell;

[0024] 11-substrate;

[0025] 12-cross-section;

[0026] 13-front surface;

[0027] 131-first passivation layer;

[0028] 14-back surface;

[0029] 141-second passivation layer;

[0030] 2-cross-section passivation layer;

[0031] 21-first cross-section passivation layer;

[0032] 22-second cross-section passivation layer;

[0033] 23-third cross-section passivation layer.

[0034] The drawings herein are incorporated into the specification and form part of the specification, show embodiments consistent with the present application, and together with the specification serve to explain the principles of the present application. DETAILED DESCRIPTION

[0035] For better understanding of the technical solutions of the present application, the embodiments of the present application are described in detail below with reference to the drawings.

[0036] It should be clear that the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0037] The terms used in the embodiments of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0038] It should be understood that the term "and / or" used herein is only to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0039] The embodiments of the present application provide a solar cell piece, as shown in Figure 1 and Figure 2 As shown, the solar cell piece includes a half-cell 1 and a cross-section passivation layer 2. Along the circumference of the solar cell piece, the side wall of the half-cell 1 has at least one cross-section 12, and the cross-section passivation layer 2 covers the cross-section 12.

[0040] In the embodiments of the present application, when the solar cell piece is cut into a half-cell 1, since the laser melts the local solar cell piece along the preset path, and then makes it break along the preset path through mechanical force, the cross-section 12 will be formed at the breaking part of the half-cell 1, and there will be laser damage, mechanical damage and surface defects on the cross-section 12. These defects are easy to become recombination centers, so that a large number of carriers will recombine based on the recombination centers, resulting in a decrease in the open-circuit voltage and short-circuit current of the half-cell 1, thereby affecting the photoelectric conversion efficiency of the half-cell 1.

[0041] Based on this, the embodiment can passivate the section 12 by setting the section passivation layer 2 and covering the section 12 of the half-cell 1, reduce the interface state defect density at the section 12, and saturate the dangling bonds, thereby reducing the possibility of the dangling bonds becoming recombination centers. The section passivation layer 2 can also introduce fixed charges to form an internal electric field on the contact surface with the section 12, thereby further inhibiting the recombination of carriers and improving the overall photoelectric conversion efficiency of the cell sheet.

[0042] In a specific embodiment, the thickness of the section passivation layer 2 along the length direction and / or the width direction of the solar cell sheet is H, and H satisfies 15 nm≤H≤100 nm. The thickness of the section passivation layer 2 can be specifically 15 nm, 17 nm, 19 nm, 21 nm, 23 nm, 25 nm, 27 nm, 29 nm, 31 nm, 33 nm, 35 nm, 37 nm, 39 nm, 41 nm, 43 nm, 45 nm, 47 nm, 49 nm, 51 nm, 53 nm, 55 nm, 57 nm, 59 nm, 61 nm, 63 nm, 65 nm, 67 nm, 69 nm, 71 nm, 73 nm, 75 nm, 77 nm, 79 nm, 81 nm, 83 nm, 85 nm, 87 nm, 89 nm, 91 nm, 93 nm, 95 nm, 97 nm, 99 nm, 100 nm, etc.

[0043] When the thickness of the section passivation layer 2 is too small (for example, H<15 nm), the section passivation layer 2 is too thin, and thus cannot effectively cover all the dangling bonds and surface defects of the section 12, so that more carriers are prone to recombine at the surface, resulting in a decrease in the open-circuit voltage and short-circuit current of the half-cell 1, and further affecting the overall photoelectric conversion efficiency of the cell sheet.

[0044] When the thickness of the section passivation layer 2 is too large (for example, H>100 nm), the section passivation layer 2 is too thick, and thus more raw materials and processing time are required, making the preparation process more complex and leading to an increase in production cost.

[0045] Therefore, when the thickness of the section passivation layer 2 satisfies 15 nm≤H≤100 nm, the thickness of the section passivation layer 2 is moderate, which effectively covers the section 12 to improve the photoelectric conversion efficiency of the half-cell 1 while reducing the overall production cost.

[0046] In a specific embodiment, as shown in FIG. 2, the section passivation layer 2 is formed on the section 12 of the half-cell 1. Figure 1 and Figure 2As shown, along the length and / or width direction of the solar cell, the passivation layer 2 has a first contact surface (not shown in the figure) on the side facing the cross-section 12. The defect state density of the first contact surface is D, and D satisfies D < 10. 8 ev -1 cm -2 .

[0047] In this embodiment of the application, when the defect state density of the first contact surface satisfies D < 10⁸ eV -1 cm -2 At this time, the lower defect state density reduces the number of recombination centers, which helps to reduce carrier loss, thereby increasing the open-circuit voltage and short-circuit current of half-cell 1, and thus improving the overall photoelectric conversion efficiency of the cell. Simultaneously, the lower defect state density also indicates higher material quality of the passivation layer 2, enabling it to better protect the cross-section 12 and reduce the impact of environmental factors such as humidity or temperature. This is beneficial for improving the stability and reliability of half-cell 1 during operation and extending its service life.

[0048] In one specific implementation, such as Figure 1 As shown, along the length and / or width direction of the solar cell, the cross-sectional passivation layer 2 includes at least a first cross-sectional passivation layer 21 and a second cross-sectional passivation layer 22. The first cross-sectional passivation layer 21 covers the cross-section 12, and the second cross-sectional passivation layer 22 covers the side of the first cross-sectional passivation layer 21 away from the cross-section 12.

[0049] In this embodiment, by setting the cross-sectional passivation layer 2 as a multi-layer structure, the first cross-sectional passivation layer 21 can undergo chemical passivation to reduce the number of recombination centers through saturated dangling bonds and repair of surface defects. The second cross-sectional passivation layer 22 can undergo field passivation to reduce the concentration of minority carriers on the surface by fixing charges to shield minority carriers, thereby further reducing the number of recombination centers. This improves the overall passivation effect of the cross-sectional passivation layer 2, thereby increasing the open-circuit voltage and short-circuit current of the half-cell 1 and improving the overall photoelectric conversion efficiency of the cell. Simultaneously, setting the cross-sectional passivation layer 2 as a multi-layer structure also improves the overall mechanical strength, reducing physical damage to the half-cell 1 and improving the structural integrity of the half-cell 1, thus enhancing the stability and reliability of the half-cell 1 during operation.

[0050] In one specific embodiment, the first cross-section passivation layer 21 comprises silicon oxide, and the second cross-section passivation layer 22 comprises a metal oxide.

[0051] The first section passivation layer 21 is configured to chemically passivate the section 12 to reduce the interface defect state density at the section 12, saturate dangling bonds on the section 12, and thus reduce the number of recombination centers. The first section passivation layer 21 is also configured to reduce the possibility of impurities polluting the section 12 during the deposition process due to the high density of the silicon oxide material. The first section passivation layer 21 is configured to cover the section 12,

[0052] The second section passivation layer 22 is configured to field passivate the section 12 to have a high density of fixed charges by the metal elements, and generate a large energy band bending between the second section passivation layer 22 and the section 12 by the electric field generated by the fixed charges, so as to reduce the possibility of the minority carriers migrating to the section 12, and thus reduce the concentration of the minority carriers at the section 12, and further reduce the possibility of the majority carriers and the minority carriers recombining at the section 12.

[0053] Therefore, by configuring the section passivation layer 2 as a multi-layer structure, the first section passivation layer 21 and the second section passivation layer 22 can cooperate with each other to simultaneously perform chemical passivation and field passivation on the section 12, which is conducive to improving the overall working performance of the battery piece and prolonging the service life of the battery piece.

[0054] In a possible implementation, the metal elements in the second section passivation layer 22 can be one or more of Al, Ti, Zn, Zr, Hf, Mo, W, and Ni.

[0055] In a specific implementation, as shown in Figure 1 The section passivation layer 2 further includes a third section passivation layer 23. The third section passivation layer 23 is located between the first section passivation layer 21 and the second section passivation layer 22. The third section passivation layer 23 and the first section passivation layer 21 both have silicon elements. The third section passivation layer 23 and the second section passivation layer 22 have the same metal elements.

[0056] In the embodiment of the present application, the third section passivation layer 23 and the first section passivation layer 21 have a second contact surface (not shown in the figure), by setting that the third section passivation layer 23 and the first section passivation layer 21 both have silicon elements, so that the crystal lattices of the surfaces (i.e. the second contact surface) in contact with each other are more adaptive, which is conducive to reducing the interface stress at the second contact surface and improving the adhesion between the third section passivation layer 23 and the first section passivation layer 21. At the same time, the third section passivation layer 23 and the second section passivation layer 22 have a third contact surface (not shown in the figure), by setting that the third section passivation layer 23 and the second section passivation layer 22 both have the same metal elements, so that the crystal lattices of the surfaces (i.e. the third contact surface) in contact with each other are more adaptive, which is conducive to reducing the interface stress at the third contact surface and improving the adhesion between the third section passivation layer 23 and the second section passivation layer 22.

[0057] Therefore, by setting that the third section passivation layer 23 and the first section passivation layer 21 both have silicon elements, and the third section passivation layer 23 and the second section passivation layer 22 have the same metal elements, the third section passivation layer 23 can act as a transition layer between the first section passivation layer 21 and the second section passivation layer 22, so that the crystal lattices at the interface (i.e. the second contact surface) where the first section passivation layer 21 and the third section passivation layer 23 contact each other and the interface (i.e. the third contact surface) where the third section passivation layer 23 and the second section passivation layer 22 contact each other are adaptive, thereby avoiding the risk of large lattice mismatch between the first section passivation layer 21 and the second section passivation layer 22 when they directly contact each other. And through such a design, the connection strength between the first section passivation layer 21 and the third section passivation layer 23, and between the third section passivation layer 23 and the second section passivation layer 22 can be improved, and the possibility of relative movement between adjacent two section passivation layers can be reduced, thereby being conducive to improving the structural stability of the section passivation layer 2 as a whole, so as to guarantee the passivation effect on the section 12.

[0058] In a specific embodiment, the thickness of the first section passivation layer 21 is h1, the thickness of the second section passivation layer 22 is h2, and the thickness of the third section passivation layer 23 is h3, and h1, h2 and h3 satisfy h1 < h3 < h2, h1 satisfies 5nm ≤ h1 ≤ 6nm, h2 satisfies 60nm < h2 ≤ 70nm, and h3 satisfies 15nm < h3 ≤ 30nm.

[0059] In the embodiments of the present application, by setting the gradually increasing thickness of the first cross-section passivation layer 21, the third cross-section passivation layer 23 and the second cross-section passivation layer 22, the overall cross-section passivation layer 2 forms a gradient structure in the direction from the first cross-section passivation layer 21 to the second cross-section passivation layer 22, so that the transition between different materials in the cross-section passivation layer 2 is smoother, which is beneficial to reduce the stress concentration and other problems caused by material properties, and improve the stability and reliability of the connection between the cross-section passivation layers.

[0060] At the same time, by such a design, the passivation mechanism of the overall cross-section passivation layer 2 can be optimized. Specifically, the thinner first cross-section passivation layer 21 is mainly used for chemical passivation, for removing interface defect states and saturating dangling bonds, so as to provide a higher quality interface; the third cross-section passivation layer 23 in the middle is mainly used for introducing field passivation effect while maintaining good chemical passivation, so as to play a good transition role; and the thicker second cross-section passivation layer 22 is mainly used for field passivation, and due to its large thickness, it can also act as an effective barrier to prevent external impurities from invading and contaminating.

[0061] Therefore, by adjusting the thicknesses of the first cross-section passivation layer 21, the second cross-section passivation layer 22 and the third cross-section passivation layer 23, the three can cooperate with each other, so that the cross-section passivation layer 2 can play a good passivation effect on the cross-section 12, thereby improving the overall working performance of the battery piece.

[0062] In a specific embodiment, the thickness of the first cross-section passivation layer 21 can be specifically 5 nm, 5.1 nm, 5.2 nm, 5.3 nm, 5.4 nm, 5.5 nm, 5.6 nm, 5.7 nm, 5.8 nm, 5.9 nm, 6 nm, etc. When the thickness of the first cross-section passivation layer 21 satisfies 5 nm≤h1≤6 nm, the thickness of the first cross-section passivation layer 21 is moderate, so that the first cross-section passivation layer 21 can play an effective chemical passivation effect on the cross-section 12 while facilitating the migration of carriers, which is beneficial to improve the photoelectric conversion efficiency of the half-piece battery 1.

[0063] In a specific embodiment, the thickness of the second cross-section passivation layer 22 can be specifically 61 nm, 62 nm, 63 nm, 64 nm, 65 nm, 66 nm, 67 nm, 68 nm, 69 nm, 70 nm, etc. When the thickness of the second cross-section passivation layer 22 satisfies 60 nm<h2≤70 nm, the thickness of the second cross-section passivation layer 22 is moderate, so that the first cross-section passivation layer 21 can play an effective field passivation effect on the cross-section 12 while preventing external impurities from invading and contaminating, which is beneficial to improve the stability and reliability of the half-piece battery 1 during operation.

[0064] In a specific embodiment, the thickness of the third facet passivation layer 23 can be specifically 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm, 30 nm, etc. When the thickness of the third facet passivation layer 23 satisfies 15 nm < h3 ≤ 30 nm, the thickness of the third facet passivation layer 23 is moderate, so that the third facet passivation layer 23 has good interface compatibility, so as to fully play a transition role, which is conducive to improving the stability and reliability of the connection between the adjacent first facet passivation layer 21 and the third facet passivation layer 23 and the connection between the third facet passivation layer 23 and the second facet passivation layer 22, thereby improving the overall structural stability of the facet passivation layer 2.

[0065] In a specific embodiment, the first facet passivation layer 21 is a SiOx layer, the fixed charge density of which is Qf1, the second facet passivation layer 22 is a SiAlOx layer, the fixed charge density of which is Qf2, the third facet passivation layer 23 is an AlOx layer, the fixed charge density of which is Qf3, and Qf1, Qf2 and Qf3 satisfy Qf1 < Qf3 < Qf2, Qf1 satisfies Qf1 < 10 12 cm -2 , Qf2 satisfies 10 14 cm -2 < Qf2, and Qf3 satisfies 10 12 cm -2 < Qf3 < 10 14 cm -2 .

[0066] In the embodiments of the present application, by setting the fixed charge densities of the first facet passivation layer 21, the third facet passivation layer 23 and the second facet passivation layer 22 to gradually increase, a stable built-in electric field can be formed in each facet passivation layer, so as to optimize the motion path of the carriers, so that the carriers can flow smoothly, thereby improving the mobility of the carriers, reducing the possibility of recombination between the majority carriers and the minority carriers, and further improving the photoelectric conversion efficiency of the half-cell 1.

[0067] Specifically, the fixed charge density Qf1 of the first facet passivation layer 21 satisfies Qf1 < 10 12 cm -2 . The first facet passivation layer 21 covers the facet 12, so as to provide a good foundation for the subsequent facet passivation layer with less fixed charge, thereby ensuring that the majority carriers can move smoothly without being disturbed too much. The first facet passivation layer 21 can be SiO2.

[0068] Specifically, the fixed charge density Qf3 of the third facet passivation layer 23 satisfies 10 12 cm -2< Qf3 < 10 14 cm -2 The third section passivation layer 23 covers the side of the first section passivation layer 21 away from the section 12 to improve the field passivation effect by an appropriate amount of fixed charge and optimize the migration path of the majority carriers, guiding them away from the area with high defect density. The third section passivation layer 23 can be Al2O3·SiO2.

[0069] Specifically, the fixed charge density Qf2 of the second section passivation layer 22 satisfies 10 14 cm -2 < Qf2. The second section passivation layer 22 covers the side of the third section passivation layer 23 away from the first section passivation layer 21 to further strengthen the field passivation effect by more fixed charge and help the stable flow of majority carriers, and provide a barrier for minority carriers to reduce the recombination loss. The second section passivation layer 22 can be Al2O3.

[0070] In a specific embodiment, as shown in Figure 1 and Figure 2 The half-cell 1 includes a substrate 11, which has a front surface 13 and a back surface 14 arranged opposite to each other along the thickness direction of the solar cell. The angle between the section 12 and the front surface 13 is a first angle, and the angle between the section 12 and the back surface 14 is a second angle. The first angle and the second angle are complementary angles, wherein the first angle is α, and the second angle is β, and α satisfies 85° < α ≤ 90°, or β satisfies 85° < β ≤ 90°.

[0071] In the embodiments of the present application, the first angle and the second angle can be 85.1°, 85.3°, 85.5°, 85.7°, 85.9°, 86°, 86.1°, 86.3°, 86.5°, 86.7°, 86.9°, 87°, 87.1°, 87.3°, 87.5°, 87.7°, 87.9°, 88°, 88.1°, 88.3°, 88.5°, 88.7°, 88.9°, 89°, 89.1°, 89.3°, 89.5°, 89.7°, 89.9°, 90°, etc.

[0072] Specifically, taking the first angle as an example, when the first angle satisfies 85° < α ≤ 90°, the section 12 can be arranged obliquely or perpendicularly to the front surface 13 along the thickness direction of the solar cell. When the section 12 is arranged obliquely to the front surface 13, the inclination of the section 12 is small, which can avoid stress concentration between the section 12 and the front surface 13, thereby reducing the possibility of fracture of the area under pressure during the assembly of the half-cell 1, and improving the structural stability of the half-cell 1.

[0073] More specifically, the cross section 12 of the half-cell 1 can be set as an inclined surface, so that the atomic arrangement density and the covalent bond surface density on the cross section 12 are smaller, and the connection stability between adjacent atoms on the cross section 12 is lower, so that the cross section passivation layer 2 bonds with the dangling bonds on the cross section 12, and the dangling bonds on the cross section 12 are easily saturated, which is beneficial to further improve the passivation effect and improve the photoelectric conversion efficiency of the half-cell 1.

[0074] In a specific embodiment, as shown in Figure 1 and Figure 2 , the front surface 13 is covered with a first passivation layer 131, and the back surface 14 is covered with a second passivation layer 141. Along the length direction and the width direction of the solar cell, the side of the cross section passivation layer 2 facing the cross section 12 covers at least the side of the first passivation layer 131, the substrate 11, and the second passivation layer 141, and the material of the cross section passivation layer 2 is the same as that of at least one of the first passivation layer 131 and the second passivation layer 141.

[0075] In the embodiments of the present application, when the material of the cross section passivation layer 2 is the same as that of at least one of the first passivation layer 131 and the second passivation layer 141, the cross section passivation layer 2 and the first passivation layer 131, or the cross section passivation layer 2 and the second passivation layer 141 can be processed by the same preparation process, which is beneficial to reduce the processing difficulty and cost of the whole half-cell 2. At the same time, using the same passivation material can ensure the consistency of charge transport inside the half-cell 1, reduce the risk of additional loss caused by different material properties, and improve the overall photoelectric conversion efficiency of the cell.

[0076] In a specific embodiment, as shown in Figure 1 and Figure 2 , the cross section passivation layer 2 extends along the thickness direction of the solar cell, one end of the cross section passivation layer 2 covers at least part of the first passivation layer 131, and / or the other end of the cross section passivation layer 2 covers at least part of the second passivation layer 141.

[0077] In the embodiments of the present application, during the preparation of the cross section passivation layer 2, the material of the cross section passivation layer 2 has the possibility of extending along the thickness direction of the solar cell towards the front surface 13, so that one end of the cross section passivation layer 2 covers the edge of the first passivation layer 131, that is, Figure 2 the dashed portion in the first passivation layer 131. At the same time, during the preparation of the cross section passivation layer 2, the material of the cross section passivation layer 2 has the possibility of extending along the thickness direction of the solar cell towards the back surface 14, so that the other end of the cross section passivation layer 2 covers the edge of the second passivation layer 141, that is, Figure 2The dashed line portion is located on the second passivation layer 141. In addition, in the process of preparing the section passivation layer 2, there is a possibility that the material of the section passivation layer 2 extends along the thickness direction of the solar cell piece and simultaneously extends towards the front surface 13 and the back surface 14, so that one end of the section passivation layer 2 covers the edge of the first passivation layer 131 and the other end covers the edge of the second passivation layer 141.

[0078] Specifically, taking the case that one end of the section passivation layer 2 covers at least part of the first passivation layer 131. Through such a design, the end of the section passivation layer 2 can provide good protection to the edge position of the first passivation layer 131 close to the section 12, which is conducive to further reducing the possibility of carrier recombination caused by interface state defects in the overlapping area of the two, thereby further improving the photoelectric conversion efficiency of the half-cell 1. It can also improve the structural strength of the overlapping area of the two, reduce the possibility of fracture of the edge position of the half-cell 1 due to mechanical stress concentration, and further improve the structural stability of the half-cell 1. It can also provide good sealing effect to the side surface of the first passivation layer 131 and the substrate 11 on the section 12, which is conducive to further reducing the possibility of external impurity invasion and pollution, and improving the stability and reliability of the half-cell 1 in the working process.

[0079] The embodiment of the present application also provides a photovoltaic module, which comprises a cover plate, an adhesive film and a cell string, the adhesive film covers one side of the cell string along the thickness direction of the solar cell piece, and the cover plate covers the side of the adhesive film away from the cell string, wherein the cell string is formed by electrically connecting a plurality of solar cell pieces, and the solar cell piece is the above-mentioned solar cell piece.

[0080] In the embodiment of the present application, the photovoltaic module can comprise a plurality of cell strings, the plurality of cell strings are electrically connected in series and / or parallel, and the solar cell pieces of each cell string all comprise the above-mentioned half-cell 1. By covering the section passivation layer 2 on the section 12 of each half-cell 1, the power loss of each cell string in the working process can be improved, thereby facilitating the improvement of the overall photoelectric conversion efficiency of the photovoltaic module.

[0081] In a possible implementation, the adhesive film comprises a first encapsulation layer and a second encapsulation layer. The first encapsulation layer covers the front surface of the cell string along the thickness direction of the solar cell piece, the second encapsulation layer covers the back surface of the cell string, and the material of the first encapsulation layer and the second encapsulation layer can be one or more of polyvinyl butyral adhesive film, ethylene-vinyl acetate copolymer adhesive film, polyethylene octene copolymer elastomer adhesive film and polyethylene terephthalate adhesive film.

[0082] In a possible implementation, the cover plate includes a first cover plate and a second cover plate. The first cover plate covers the side of the first adhesive film away from the battery string along the thickness direction of the solar cell, the second cover plate covers the side of the second adhesive film away from the battery string, and the surfaces of the first cover plate and the second cover plate on the side of the adhesive film are both concave-convex structures to increase the utilization rate of incident light. The first cover plate and the second cover plate can be made of glass or plastic.

[0083] In a possible implementation, the solar cell includes, but is not limited to, a passivated emitter and rear cell (PERC), an interdigitated back contact (IBC), a tunnel oxide passivated contact (TOPCon), a heterojunction technology (HJT), a solar thin film cell, and a stacked cell.

[0084] The solar thin film cell includes, but is not limited to, a perovskite solar thin film cell, a copper indium selenium solar thin film cell, a gallium arsenide solar thin film cell, and a cadmium sulfide solar thin film cell. The stacked cell includes, but is not limited to, a perovskite cell stacked with a crystalline silicon cell, a perovskite cell stacked with a perovskite cell, and a perovskite cell stacked with a thin film cell.

[0085] The above embodiments shown in the drawings explain the structure, features, and effects of the present application in detail. The above description is only the preferred embodiments of the present application, but the present application is not limited by the drawings. Any changes or modifications made in accordance with the concept of the present application, or equivalent embodiments with equivalent changes, are still within the scope of the present application.

Claims

1. A solar cell, characterized by, The solar cell piece comprises: a half-cell, a side wall of the half-cell having at least one section along a circumferential direction of the solar cell piece; a section passivation layer covering the section; wherein a thickness of the section passivation layer is H along a length direction and / or a width direction of the solar cell piece, and H satisfies 15nm≤H≤100nm.

2. The solar cell according to claim 1, wherein The cross-section passivation layer has a first contact surface on the side facing the cross-section along the length direction and / or the width direction of the solar cell piece, and a defect state density of the first contact surface is D, and D satisfies D < 10 8 ev -1 cm -2 .

3. The solar cell of claim 1, wherein, The section passivation layer comprises at least a first section passivation layer and a second section passivation layer along the length direction and / or the width direction of the solar cell piece, the first section passivation layer covering the section, and the second section passivation layer covering a side of the first section passivation layer away from the section; wherein the first section passivation layer comprises silicon oxide, and the second section passivation layer comprises metal oxide.

4. The solar cell of claim 3, wherein, The section passivation layer further comprises a third section passivation layer between the first section passivation layer and the second section passivation layer, the third section passivation layer and the first section passivation layer both having silicon element, and the third section passivation layer and the second section passivation layer having the same metal element.

5. The solar cell of claim 4, wherein, A thickness of the first section passivation layer is h1, a thickness of the second section passivation layer is h2, and a thickness of the third section passivation layer is h3, and h1, h2 and h3 satisfy h1 6. The solar cell of claim 4, wherein, The first section passivation layer is a SiOx layer, the fixed charge density of which is Qf1, the second section passivation layer is a SiAlOx layer, the fixed charge density of which is Qf2, the third section passivation layer is an AlOx layer, the fixed charge density of which is Qf3, and Qf1, Qf2 and Qf3 satisfy Qf1 < Qf3 < Qf2, Qf1 satisfies Qf1 < 10 12 cm -2 , Qf2 satisfies 10 14 cm -2 < Qf2, and Qf3 satisfies 10 12 cm -2 < Qf3 < 10 14 cm -2 .

7. The solar cell according to any one of claims 1-6, wherein, The half-cell comprises a substrate, the substrate having a front side and a back side oppositely arranged along a thickness direction of the solar cell piece, an included angle between the section and the front side is a first included angle, and an included angle between the section and the back side is a second included angle, the first included angle and the second included angle being complementary angles; wherein the first included angle is α, and the second included angle is β, and α satisfies 85°<α≤90°, or β satisfies 85°<β≤90°.

8. The solar cell of claim 7, wherein, The front side is covered with a first passivation layer, and the back side is covered with a second passivation layer, and along the length direction and the width direction of the solar cell piece, a side of the section passivation layer away from the section covers at least a side of the first passivation layer, the substrate and the second passivation layer; wherein a material of the section passivation layer is the same as that of at least one of the first passivation layer and the second passivation layer.

9. The solar cell of claim 8, wherein, The section passivation layer extends along the thickness direction of the solar cell piece, one end of the section passivation layer covering at least part of the first passivation layer, and / or the other end of the section passivation layer covering at least part of the second passivation layer.

10. A photovoltaic module, characterized by, The photovoltaic module comprises: a cover plate; an adhesive film; a cell string comprising a plurality of solar cell pieces, the solar cell piece being the solar cell piece according to any one of claims 1-9; wherein along a thickness direction of the solar cell piece, the adhesive film covers one side of the cell string, and the cover plate covers a side of the adhesive film away from the cell string.

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