Solar cell and photovoltaic module

Abstract

The invention discloses a solar cell and a photovoltaic module. The solar cell comprises a silicon substrate; a plurality of grooves are formed in the first surface of the silicon substrate, and the first surface has a first direction and a second direction which are intersected; the plurality of grooves are arranged at intervals along a first direction and penetrate through the silicon substrate along a second direction. According to the solar cell structure, the flexibility and the high conversion efficiency of the cell are considered at the same time, the solar cell structure can be better suitable for a curved surface application scene, and the power generation performance of the cell can be improved.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, and particularly relates to a solar cell and a photovoltaic module. Background Art

[0002] With the continuous development of photovoltaic technology, the application requirements of photovoltaic modules are becoming more and more diverse. For example, they are applied to curved application scenarios such as building roofs and vehicle roofs. In these application scenarios, the photovoltaic modules are required to have a certain degree of flexibility.

[0003] In current solar cells, in order to ensure the conversion efficiency, the silicon wafers used to make the solar cells usually have a certain thickness, and the toughness of the cell wafers is poor, which cannot be applied to curved application scenarios. In related technologies, by reducing the thickness of the silicon wafer, the cell wafer is made to have a certain degree of flexibility, but the thinner thickness will cause the light absorption rate of the cell wafer to decrease, thereby resulting in a lower cell efficiency.

[0004] In some other existing technologies, as Figure 8 shown, by forming holes 6 in the cell 1 to increase the flexibility of the cell 1, a bendable cell wafer is made. However, for the cell formed in this way, as Figure 8 shown by the dashed box in, a structure similar to a rib will be formed in the part between two adjacent holes 6. In this way, it is not conducive to the bending of the cell wafer, and thus will affect the curvature of the cell. Moreover, forced bending will cause irreversible damage to the part of the cell where the holes 6 are not provided. Therefore, there is an urgent need for a solar cell with both flexibility and high efficiency to solve the above problems. Summary of the Invention

[0005] In order to solve the above technical problems, the present application is implemented as follows:

[0006] In a first aspect, an embodiment of the present application provides a solar cell, including: a silicon substrate; a plurality of grooves are provided on a first surface of the silicon substrate, and the first surface has an intersecting first direction and a second direction; the plurality of grooves are arranged at intervals along the first direction, and the grooves penetrate through the silicon substrate along the second direction.

[0007] Optionally, the groove has a groove wall, and at least part of the groove wall is provided with an uneven structure. Preferably, the uneven structure includes a pyramid structure or an inverted pyramid structure.

[0008] Optionally, the extending directions of the plurality of grooves are all parallel.

[0009] Optionally, the first surface has two opposite long sides and two opposite short sides, the length of the long side is greater than the length of the short side, and the extending direction of the groove is parallel to the long side or parallel to the short side;

[0010] And / or, multiple said grooves are arranged at equal intervals.

[0011] Optionally, it further includes a passivation layer, the passivation layer is disposed on the first surface, the passivation layer at least partially covers the groove wall of the groove, the radius of curvature of the battery in the bent state is R μm, and the thickness of the battery at the bottom of the groove is H1 μm, satisfying: 1500 ≤ R / H1 ≤ 10000.

[0012] Optionally, the width of the groove in the notch along the first direction is W1 μm, and the depth of the groove is H2 μm, satisfying: 0.1 ≤ W1 / H2 ≤ 10.

[0013] Optionally, the depth of the groove is H2 μm, and the thickness of the part of the battery other than the groove is H3 μm, satisfying: 0.1 ≤ H2 / H3 ≤ 0.9.

[0014] Optionally, the width of the groove in the notch along the first direction is W1 μm, and the distance between two adjacent grooves is W2 μm, satisfying: 0.1 ≤ W2 / W1 ≤ 10.

[0015] Optionally, the solar cell satisfies at least one of the following conditions:

[0016] A. The thickness H1 of the battery at the bottom of the groove is H1 ≥ 15 μm;

[0017] B. The depth H2 of the groove satisfies: 15 μm ≤ H2 ≤ 100 μm;

[0018] C. The thickness of the part of the battery other than the groove is H3, satisfying: 50 μm ≤ H3 ≤ 300 μm;

[0019] D. The width W1 of the groove in the notch along the first direction satisfies: 9 μm ≤ W1 ≤ 200 μm;

[0020] F. The cross-sectional shape of the groove along the direction perpendicular to the second direction includes one or a combination of two or more of a circular arc shape, an elliptical arc shape, and a polygon.

[0021] In a second aspect, an embodiment of the present application provides a photovoltaic module, including the solar cell according to any one of the first aspect.

[0022] In the embodiments of the present application, by providing a plurality of grooves arranged at intervals on the surface of the silicon substrate, the thickness of the battery at the grooves is reduced, so that the battery has strong toughness and low brittleness at the grooves, enabling the battery to be bent and deformed. At the same time, in the part of the battery where no grooves are provided, sufficient thickness can be maintained to ensure strong light absorption ability. Moreover, when incident light irradiates the first surface, multiple reflections can occur on the groove walls to form a light trapping effect, thereby increasing the light absorption rate of the battery. In this way, by adopting the solar cell structure of the present application, both the flexibility and the high conversion efficiency of the battery are taken into account, which can not only be better applied to curved application scenarios, but also improve the performance of the battery.

[0023] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented in accordance with the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specific embodiments of the present application are specifically exemplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments. Among them:

[0025] Figure 1 is a schematic diagram of a solar cell according to an embodiment of the present application;

[0026] Figure 2 is a side view of a solar cell according to an embodiment of the present application;

[0027] Figure 3 is a schematic diagram of the light trapping effect of a solar cell according to an embodiment of the present application in a flattened state;

[0028] Figure 4 is a schematic diagram of the light trapping effect of a solar cell according to an embodiment of the present application in a bent state;

[0029] Figure 5 is another schematic diagram of the structure of a solar cell according to an embodiment of the present application;

[0030] Figure 6 is still another schematic diagram of the structure of a solar cell according to an embodiment of the present application;

[0031] Figure 7 is a schematic diagram of a photovoltaic module according to an embodiment of the present application;

[0032] Figure 8 is a schematic diagram of a solar cell of the prior art.

[0033] Reference numerals:

[0034] 1: Battery; 10: First surface; 11: Long side; 12: Short side; 13: Silicon substrate; 2: Groove; 3: Encapsulation material layer; 4: Rear cover plate; 5: Front cover plate; X: First direction; Y: Second direction; 6: Hole. Detailed implementation manners

[0035] Embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0036] The terms "first" and "second" in the description and claims of the present application may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, "a plurality of" means two or more. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally means an "or" relationship between the associated objects before and after.

[0037] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0038] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0039] The solar cell and photovoltaic module provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0040] As Figure 1 and Figure 2 shown, the solar cell 1 according to some embodiments of the present application includes: a silicon substrate 13; a plurality of grooves 2 are provided on a first surface 10 of the silicon substrate 13, and the first surface 10 has intersecting first direction X and second direction Y; the plurality of grooves 2 are arranged at intervals along the first direction X, and the grooves 2 penetrate the silicon substrate 13 along the second direction Y, and the silicon substrate 13 can be bent and deformed in a direction perpendicular to the first surface 10. It should be noted that the intersection includes but is not limited to perpendicular intersection.

[0041] In the embodiments of the present application, by providing a plurality of grooves 2 arranged at intervals on the surface of the silicon substrate 13, the thickness of the cell 1 at the grooves 2 is reduced, so that the cell 1 has strong toughness and low brittleness at the grooves 2, so that the cell 1 can be bent and deformed; at the same time, the part of the cell 1 where the grooves 2 are not provided can maintain a sufficient thickness to ensure strong light absorption ability. And when the incident light irradiates the first surface 10, multiple reflections can be generated on the groove walls of the grooves 2 to form a light trapping effect, thereby increasing the light absorption rate of the cell 1. In this way, by adopting the solar cell structure of the present application, while taking into account the flexibility of the cell and the higher conversion efficiency, it can not only be better applied to the curved surface application scenario, but also improve the power generation performance of the cell.

[0042] It can be understood that the solar cell of the present application may include PERC cells, TOPCon cells, HJT cells, BC cells, etc. Of course, the solar cell structure of the present application is not limited to being applied to the foregoing types, and those skilled in the art can flexibly set according to actual selection.

[0043] Specifically, the solar cell 1 includes a silicon substrate 13, and the silicon substrate 13 can generate a photovoltaic effect under sunlight irradiation. The first surface 10 may be the light-receiving surface of the silicon substrate 13, that is, the surface of the silicon substrate 13 irradiated by the incident light. Furthermore, a plurality of grooves 2 are provided in the first surface 10 of the silicon substrate 13, and the grooves 2 are recessed from the first surface 10 into the silicon substrate 13. The plurality of grooves 2 are arranged at intervals along the first direction X, and the grooves 2 penetrate the silicon substrate 13 along the second direction Y.

[0044] It should be noted that the groove 2 may extend linearly, curvilinearly, or in a broken line along the second direction Y, and the embodiments of the present application do not limit this. Moreover, the groove 2 penetrates the silicon substrate 13 along the second direction Y to ensure that when the battery 1 is bent and deformed, the stress received at different positions on the bottom of the groove 2 is more uniform. The groove 2 penetrates the silicon substrate 13 along the second direction Y, that is, the groove 2 extends from one edge of the first surface 10 to the other edge along the second direction Y. It can be understood that in the actual processing process, due to processing conditions or processing methods, there is a certain distance between the end of the groove 2 and the side edge of the silicon substrate 13, such as not exceeding 2 mm, preferably not exceeding 1 mm, which is also regarded as the groove 2 penetrating the silicon substrate 13 along the second direction Y.

[0045] It can be understood that in the solar cell 1, as the thickness of the silicon substrate 13 decreases, its toughness will increase, but as the thickness of the silicon substrate 13 decreases, its light absorption rate will also decrease, resulting in a reduction in the conversion efficiency of the battery. In the present application, by providing a plurality of grooves 2 in the silicon substrate 13 to thin part of the area in the battery 1, in this way, the thickness of the part of the battery 1 where the grooves 2 are provided is relatively thin, which can improve the toughness of this part of the battery 1 and reduce brittleness, so that the battery 1 has a certain flexible deformation ability and can thus be bent. And for the part of the battery 1 other than where the grooves 2 are provided, it is not thinned and can maintain a certain thickness, which can ensure a strong light absorption ability, thereby ensuring the conversion efficiency of the solar cell. In addition, when the incident light refracts into the groove, it can be reflected multiple times between the groove walls of the groove 2 and be effectively absorbed by the battery 1, thereby improving the conversion efficiency of the battery. This can not only make the battery flexible but also maintain a high conversion efficiency.

[0046] In some embodiments, the solar cell of the present application can be a full-cell, half-cell, or third-cell, etc.

[0047] In some other embodiments, as Figure 2 、 Figure 5 and Figure 6 shown, the cross-sectional shape of the groove 2 perpendicular to the second direction Y includes one or a combination of two or more of an arc shape, an elliptical arc shape, and a polygon. Among them, the polygon includes but is not limited to: a square, a rectangle, a trapezoid, etc. Of course, the specific shape and structure of the groove 2 can be flexibly set according to actual needs and are not limited here.

[0048] Optionally, the groove 2 has a groove wall, and at least part of the groove wall is provided with a concavo-convex structure.

[0049] In the embodiments of the present application, by providing an uneven structure on at least part of the groove walls of the groove 2, a light trapping effect is formed on the groove walls by the uneven structure. When incident light irradiates the first surface 10, on the one hand, the groove walls of the groove 2 reflect the incident light multiple times to form a primary light trapping effect, and on the other hand, the light irradiated on the groove walls can be reflected again by the uneven structure to form a secondary light trapping effect. In this way, it helps to further improve the light absorption rate of the battery 1, thereby improving the conversion efficiency of the battery.

[0050] In some embodiments, the uneven structure includes a pyramid structure or an inverted pyramid structure. For example, during the battery manufacturing process, a pyramidal or inverted pyramidal nap structure can be formed on the groove walls of the groove 2 through a texturing process. Specifically, a nap structure can be formed on the side walls and / or the bottom wall of the groove 2. Of course, the uneven structure can also be set to other structures that can produce a light trapping effect, and those skilled in the art can set it flexibly according to the actual situation, which is not limited herein.

[0051] Optionally, as Figure 1 shown, the extending directions of the multiple grooves 2 are all parallel. By arranging the multiple grooves 2 in parallel, the arrangement regularity of the multiple grooves 2 on the battery 1 is improved, which helps to improve the bendable deformation ability of the battery 1. At the same time, it is also convenient for design and processing.

[0052] In some embodiments, as Figure 1 and Figure 2 shown, the multiple grooves 2 can be arranged at equal intervals, that is, the intervals between any two adjacent grooves 2 are equal.

[0053] By arranging the multiple grooves 2 at equal intervals, when the battery 1 is bent and deformed, it can ensure that the force distribution at different positions in the battery 1 is more uniform, thereby reducing the risk of hidden cracks or breakage caused by local stress concentration in the battery 1.

[0054] Optionally, as Figure 1 shown, the first surface 10 has two opposite long sides 11 and two opposite short sides 12, the length of the long side 11 is greater than the length of the short side 12, and the extending direction of the groove 2 is parallel to the long side 11 or parallel to the short side 12.

[0055] It can be understood that in the process of preparing a photovoltaic module from solar cells, electrical connectors (such as solder tapes) are needed to connect multiple solar cells in series to form a cell string. During the series connection process, in order to improve the compactness and regularity of the layout structure, the solar cells are arranged in a way that the sides of adjacent solar cells are parallel. Therefore, in the embodiments of the present application, by setting the extending direction of the groove 2 in the battery 1 to be parallel to the long side 11 or the short side 12 of the first surface 10, when connecting multiple solar cells in series, it can ensure the consistency of the bending deformation directions of the multiple solar cells, thereby improving the bendability and structural regularity of the prepared photovoltaic module.

[0056] It should be noted that the extending direction of the groove 2 in the present application is not limited to being parallel to the long side 11 and the short side 12, and can also be flexibly set according to actual application needs to meet different application scenarios. For example, the extending direction of the groove 2 can also be set to be parallel to the diagonal of the first surface 10, which is not limited herein.

[0057] Optionally, the battery 1 has a flattened state and a bent state. Among them, as Figure 3 shown, in the flattened state, the first surface 10 of the battery 1 is a plane or an approximate plane; as Figure 4 shown, in the bent state, the first surface 10 of the battery 1 is a curved surface.

[0058] Optionally, the solar cell further includes a passivation layer, and the passivation layer is provided on the first surface, and the passivation layer at least partially covers the groove wall of the groove 2. In the embodiments of the present application, by providing a passivation layer on the first surface of the silicon substrate 13, the passivation layer at least partially covers the groove wall of the groove 2 to reduce the recombination effect of non-equilibrium carriers on the groove wall of the groove 2, thereby improving the conversion efficiency of the solar cell.

[0059] Optionally, the radius of curvature of the solar cell in the bent state is R μm, and the thickness of the battery 1 at the bottom of the groove 2 is H1 μm, satisfying: 1500*H1 ≤ R ≤ 10000*H1.

[0060] It can be understood that when the radius of curvature R < 1500*H1, the battery chip is overly bent, which will cause irreversible damage such as cracks in the passivation layer, thereby affecting the conversion efficiency of the solar cell; when R > 10000*H1, the battery chip cannot form enough bending to meet the design requirements. At the same time, by controlling the thickness of the battery 1 at the bottom of the groove 2 to be H1 and the radius of curvature R of the solar cell in the bent state, the bendable deformation ability of the battery and a relatively high conversion efficiency can be taken into account.

[0061] The radius of curvature refers to the radius of curvature corresponding to any point on the curved surface of the battery when it is in a bent state. When measuring the radius of curvature, the curved battery in the finished battery assembly can be measured. For example, the finished battery assembly can be cut to expose the curved section of the battery, so as to obtain the radius of curvature of the battery according to the curved section. The finished battery assembly can also be disassembled to remove some battery cells, and the radius of curvature corresponding to any point on the curved surface can be measured when the battery cells are bent under force. During measurement, the degree of bending of the battery cells can be kept roughly the same as that of the specific usage scenario, or the curvature can be measured while ensuring that the battery is in a state of bending. The cell can be bent as far as possible without destroying the macro structure of the cell. During measurement, the passivation layer, anti-reflection film and electrode on the cell can be retained, or the passivation layer, anti-reflection film or electrode can be partially or completely peeled off, and the present application does not impose any restrictions on this. A single cell that has not formed a battery assembly can also be bent. During measurement, the degree of bending of the cell can be kept roughly the same as that of the specific usage scenario, or the cell can be bent as far as possible while ensuring that the macro structure of the cell is not destroyed, and then the radius of curvature corresponding to any point on the curved surface is measured. The above measurement methods are only examples, and the present application does not impose any restrictions on this.

[0062] The thickness H1 of the battery 1 at the bottom of the groove 2 is the distance from any point of the bottom of the groove 2 to the side of the battery 1 away from the first surface 10 along the thickness direction of the battery 1 .

[0063] Exemplarily, the ratio of the radius of curvature R of the battery in a bent state to the thickness H1 of the battery 1 at the bottom of the groove 2 can be set to: 1500, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, etc.

[0064] Alternatively, if Figure 2 As shown, the width of the groove 2 along the first direction X at the notch is W1 μm, and the depth of the groove 2 is H2 μm, satisfying: 0.1≤W1 / H2≤10. For example, W1 / H2 can be set to: 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0065] In the embodiment of the present application, by setting the ratio of the width W1 of the groove 2 along the first direction X at the notch to the depth H2 of the groove 2 in the range of 0.1-10, it can ensure that the battery 1 has a certain flexibility at the groove 2 so that it can bend and deform, and at the same time, it can also ensure that the groove 2 can form a light trapping effect, thereby improving the light absorption rate of the battery 1, thereby improving the conversion efficiency of the solar cell.

[0066] Among them, the width W1 of the groove 2 at the notch is the distance between the opposite two side walls at the notch of the groove 2 along the first direction X; the depth H2 of the groove 2 is the depth at any position of the groove 2 along the thickness direction of the battery 1.

[0067] It can be understood that when the W1 / H2 is less than 0.1, either the groove 2 is set too deep. Given the certain overall thickness of the battery 1, the battery 1 at the bottom of the groove 2 will be too thin, reducing the structural strength of the battery 1 at the groove 2. At the same time, the too thin silicon substrate 13 has a large volume resistance, which is not conducive to the transmission of carriers; or the width of the groove 2 is too small, that is, the groove 2 has a slit structure, which is not conducive to light entering the groove 2 to form a light trapping effect.

[0068] And when the W1 / H2 is greater than 10, either the depth of the groove 2 is too shallow, and the toughness of the battery 1 at the groove 2 is insufficient to meet the bending deformation requirements of the overall battery 1; or the width of the groove 2 is too large, which will occupy a large space on the first surface 10, reducing the area of the non-thinned area of the battery 1, thereby affecting the conversion efficiency of the solar cell.

[0069] Optionally, as Figure 2 shown, the depth of the groove 2 is H2 μm, and the thickness of the part of the battery 1 other than the groove 2 is H3 μm, satisfying: 0.1 ≤ H2 / H3 ≤ 0.9. For example, the H2 / H3 can be set to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, etc.

[0070] It can be understood that when the groove 2 is provided in the battery 1, the depth of the groove 2 is equivalent to the size of the local thickness reduction of the battery 1. If the thickness reduction at the groove 2 is too small, it cannot play a role in improving the toughness of the corresponding part of the battery 1, thereby affecting the bending deformation ability of the battery 1; and if the thickness reduction at the groove 2 is too large, it will cause the structural strength at different positions of the battery 1 to vary greatly, making the battery 1 prone to local cracking when bent. Therefore, in this application, by setting a reasonable ratio range of the depth H2 of the groove 2 to the thickness H3 of the part of the battery 1 other than the groove 2, while improving the bendable deformation ability of the battery 1, the overall structural strength of the battery 1 is taken into account, thereby improving the service performance of the solar cell.

[0071] Among them, the thickness H3 μm of the part of the battery 1 other than the groove 2 is the distance between the opposite two surfaces of the part of the battery 1 where the groove 2 is not provided along the direction perpendicular to the first surface.

[0072] Optionally, as Figure 2As shown, the width of the groove 2 along the first direction X at the notch is W1 μm, and the distance between two adjacent grooves 2 is W2 μm, satisfying: 0.1 ≤ W2 / W1 ≤ 10. For example, the W2 / W1 can be set to 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0073] It can be understood that when the area of the first surface 10 of the silicon substrate 13 is fixed, if the groove 2 is set too wide, it will affect the area of the part without the groove 2, and further reduce the conversion efficiency of the battery 1; while if the distance between two adjacent grooves 2 is too large, it will limit the number of grooves 2 and the width of the groove 2. In this way, the effect of improving the bendable deformation of the silicon substrate 13 by setting the groove 2 is limited, and it is not conducive to forming an effective light trapping effect through the groove 2. Therefore, in this application, by setting the W2 / W1 within a reasonable range, the bendable deformation ability of the battery 1 can be improved by setting the groove 2, and the conversion efficiency of the battery 1 can be taken into account at the same time.

[0074] In some embodiments, the thickness H1 of the battery 1 at the bottom of the groove 2 is H1 ≥ 15 μm. For example, the H1 can be set to: 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 50 μm, 80 μm, etc.

[0075] In the embodiments of this application, by setting the thickness H1 of the battery 1 at the bottom of the groove 2 to be greater than or equal to 15 μm, the battery 1 can have a certain deformability by setting the groove 2. At the same time, by controlling the thickness of the battery 1 at the bottom of the groove 2, the structural strength and light absorption ability of the battery 1 in this part can be ensured.

[0076] It can be understood that if the thickness of the battery 1 at the groove 2 is less than 15 μm, the thickness of the battery 1 at the groove 2 is too thin and the structural strength is low. When the battery 1 is bent, it is easy to crack at the corresponding position of the groove 2. Moreover, the thinner silicon substrate 13 not only has a poor light absorption ability, but also has a high volume resistance, which is not conducive to the flow of carriers.

[0077] In some embodiments, the depth H2 of the groove 2 satisfies: 15 μm ≤ H2 ≤ 100 μm. For example, the depth H2 of the groove 2 can be set to: 15 μm, 20 μm, 30 μm, 4 μm, 5 μm, 6 μm, 7 μm, 80 μm, 90 μm, 100 μm, etc.

[0078] In the embodiments of the present application, by controlling the depth of the groove 2 in the battery 1, while ensuring that the battery 1 has a certain bending deformation ability, it is avoided that the depth of the groove 2 is too deep, which is not conducive to forming a light trapping effect. Moreover, when the total thickness of the battery 1 is certain, if the depth of the groove 2 is too deep, the thickness of the battery 1 at the groove 2 is too thin. In this way, the local structural strength and light absorption performance of the battery 1 will be reduced.

[0079] In some embodiments, the thickness H3 of the part of the battery 1 other than the groove 2 satisfies: 50 μm ≤ H3 ≤ 300 μm. For example, the thickness H3 can be set to: 50 μm, 80 μm, 100 μm, 120 μm, 130 μm, 150 μm, 200 μm, 250 μm, 300 μm, etc.

[0080] In the present application, by setting the thickness range of the thickness H3 of the part of the battery 1 other than the groove 2, it is ensured that the part of the battery 1 other than the area where the groove 2 is provided can have a certain thickness, so as to ensure the light absorption rate and improve the overall conversion efficiency of the battery.

[0081] In some embodiments, the width W1 of the groove 2 at the groove opening along the first direction X satisfies: 10 μm ≤ W1 ≤ 200 μm. For example, the width W1 can be set to 10 μm, 20 μm, 50 μm, 80 μm, 100 μm, 150 μm, 200 μm, etc.

[0082] In the embodiments of the present application, by setting the range of the width W1 of the groove 2 at the groove opening along the first direction X to be between 10 μm and 200 μm, it is ensured that the groove 2 has a certain width at the groove opening, which can allow incident light to enter the groove 2 to form a light trapping effect and is also convenient for processing; at the same time, it is avoided that the width of the groove 2 at the groove opening is too large, which affects the area of the region of the battery 1 where the groove 2 is not provided, so as to ensure that the solar cell can have a high conversion efficiency.

[0083] In some embodiments, electrodes can also be laid on the first surface. The electrodes can be laid along the extension direction of the groove 2 and are arranged in the region of the battery 1 where the groove 2 is not provided. Or, the electrodes can also be laid along a direction intersecting the extension direction of the groove 2, that is, the electrodes can be laid across multiple grooves 2.

[0084] In some embodiments, the solar cells of the present application and the conventional solar cells without the groove 2 are tested by the standard test condition (STC) test method. The difference amplitude of the calibrated power of the solar cells of the present application compared with the conventional cells is less than 1%.

[0085] Furthermore, under standard test conditions, the incident light obliquely irradiates the first surface of the silicon substrate, and the angle between the incident light and the normal of the first surface is the incident angle. When the incident angle is 45°, the power generation of a conventional solar cell is 90% of the rated power, while that of the solar cell of the present invention is 95% of the rated power; when the incident angle is 60°, the power generation of a conventional solar cell is 70% of the rated power, while that of the solar cell of the present invention is 90% of the rated power; when the incident angle is 70°, the power generation of a conventional solar cell is 45% of the rated power, while that of the solar cell of the present invention is 80% of the rated power. Thus, compared with conventional solar cells, the solar cell of the present application can still maintain a high power generation efficiency when the incident light is incident at a large angle.

[0086] Optionally, an embodiment of the present application further provides a method for manufacturing a solar cell for manufacturing the solar cell in the above embodiment, including:

[0087] Form a plurality of grooves 2 in the first surface of the silicon substrate 13; the first surface has an intersecting first direction X and a second direction Y, and the plurality of grooves 2 are arranged at intervals along the first direction X, and the grooves 2 penetrate the silicon substrate 13 along the second direction Y, and the silicon substrate 13 can be bent and deformed in a direction perpendicular to the first surface.

[0088] In the embodiment of the present application, by forming a plurality of grooves 2 arranged at intervals on the surface of the silicon substrate 13, the thickness of the battery 1 at the grooves 2 is reduced, so that the battery 1 has strong toughness and low brittleness at the grooves 2, so that the battery 1 can be bent and deformed; at the same time, the battery 1 can maintain a sufficient thickness at the part where the grooves 2 are not provided to ensure strong light absorption ability. And when the incident light irradiates the first surface 10, multiple reflections can be generated on the groove walls of the grooves 2 to form a light trapping effect, thereby increasing the light absorption rate of the battery 1. In this way, adopting the solar cell structure of the present application, while taking into account the flexibility of the battery and a high conversion efficiency, it can not only be better applied to curved surface application scenarios, but also improve the power generation performance of the battery.

[0089] In a specific application, the grooves 2 can be formed in the silicon substrate 13 by means of laser etching or chemical etching first; then, a passivation layer and an antireflection film layer are formed on the surface of the silicon substrate 13 in sequence.

[0090] Alternatively, the passivation layer and the antireflection film layer can also be formed on the surface of the silicon substrate 13 in sequence first; then, the grooves 2 are formed by means of laser etching or chemical etching, etc., so that the grooves 2 extend into the silicon substrate 13; finally, a passivation layer is formed on the groove walls of the grooves 2.

[0091] Optionally, an embodiment of the present application further provides a photovoltaic module, including the solar cell in the above embodiment.

[0092] In the embodiment of the present application, by providing a plurality of grooves 2 arranged at intervals on the surface of the silicon substrate 13 in the solar cell, the thickness of the cell 1 at the grooves 2 is reduced, so that the cell 1 has strong toughness and low brittleness at the grooves 2, so that the cell 1 can be bent and deformed; at the same time, the cell 1 can maintain a sufficient thickness at the part where the grooves 2 are not provided to ensure a strong light absorption ability. And when the incident light irradiates the first surface 10, multiple reflections can be generated on the groove walls of the grooves 2 to form a light trapping effect, thereby increasing the light absorption rate of the cell 1. In this way, adopting the solar cell structure of the present application, while taking into account the flexibility of the cell and a high conversion efficiency, it can not only be better applied to curved application scenarios, but also improve the power generation performance of the cell.

[0093] In some embodiments, as Figure 7 shown, the photovoltaic module further includes a packaging material layer 3. A plurality of solar cells in the above embodiment are connected in series to form a cell string through electrical connectors such as solder tapes, and then the cell string is embedded in the packaging material layer 3, so that the packaging material layer 3 covers the periphery of the cell string to form a packaging protection for the cell string.

[0094] Among them, the packaging material layer 3 can be made of a flexible material, so that the photovoltaic module formed after the cell string is embedded in the packaging material layer 3 has a certain flexibility and can be curled, so as to be applicable to scenarios with a large bending curvature requirement. For example, it can be applied to photovoltaic power generation blankets or other mobile terminal products.

[0095] In other embodiments, the photovoltaic module further includes a front cover plate 5 and a back cover plate 4, which are arranged on both sides of the packaging material layer 3 to play a role of support and protection. For example, the front cover plate 5 and the back cover plate 4 can be structural members made of inorganic glass, organic glass, or other transparent materials.

[0096] Among them, the front cover plate 5 and the back cover plate 4 can have a certain bending curvature. Then, after the packaging material layer 3 embedded with the cell string is clamped between the front cover plate 5 and the back cover plate 4, a curved photovoltaic module with a certain bending curvature can be prepared, and then it can be applied to curved application scenarios such as BIPV buildings and vehicle roofs.

[0097] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0098] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A solar cell, characterized in that: include: Silicon substrate; The first surface of the silicon substrate is provided with a plurality of grooves, and the first surface has a first direction and a second direction intersecting with each other; A plurality of the grooves are arranged at intervals along the first direction, and the grooves penetrate the silicon substrate along the second direction.

2. The solar cell according to claim 1, characterized in that The groove has a groove wall, and at least a portion of the groove wall is provided with a concave-convex structure. Preferably, the concave-convex structure includes a pyramid structure or an inverted pyramid structure.

3. The solar cell according to claim 1, characterized in that The extension directions of the plurality of grooves are all parallel.

4. The solar cell according to claim 3, characterized in that: The first surface has two opposite long sides and two opposite short sides, the length of the long sides is greater than the length of the short sides, and the extension direction of the groove is parallel to the long sides or parallel to the short sides; And / or, the plurality of grooves are arranged at equal intervals.

5. The solar cell according to any one of claims 1 to 4, characterized in that: It also includes a passivation layer, which is arranged on the first surface and at least partially covers the groove wall of the groove; the curvature radius of the battery in a bent state is Rμm, and the thickness of the battery at the bottom of the groove is H1μm, satisfying: 1500*H1≤R≤10000*H1.

6. The solar cell according to any one of claims 1 to 4, characterized in that: The width of the groove along the first direction at the notch is W1 μm, and the depth of the groove is H2 μm, satisfying: 0.1≤W1 / H2≤10.

7. The solar cell according to any one of claims 1 to 4, characterized in that: The depth of the groove is H2 μm, and the thickness of the battery except for the groove is H3 μm, satisfying: 0.1≤H2 / H3≤0.

9.

8. The solar cell according to any one of claims 1 to 4, characterized in that: The width of the groove along the first direction at the notch is W1 μm, and the distance between two adjacent grooves is W2 μm, satisfying: 0.1≤W2 / W1≤10.

9. The solar cell according to any one of claims 1 to 4, characterized in that: The solar cell meets at least one of the following conditions: A. The thickness H1 of the battery at the bottom of the groove is ≥ 15 μm; B. The depth H2 of the groove satisfies: 15 μm ≤ H2 ≤ 100 μm; C. The thickness H3 of the battery except for the groove satisfies: 50 μm ≤ H3 ≤ 300 μm; D. The width of the groove along the first direction at the notch is W1, satisfying: 10 μm ≤ W1 ≤ 200 μm; F. The cross-sectional shape of the groove along the direction perpendicular to the second direction includes one or a combination of two or more of a circular arc, an elliptical arc, and a polygon.

10. A photovoltaic module, characterized in that: The invention comprises a solar cell as claimed in any one of claims 1 to 9.

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