Solar cell and cell module

Abstract

The utility model is applicable to the field of photovoltaic technology, and provides a solar cell and a cell module, the solar cell comprises a silicon substrate, the silicon substrate is provided with a first surface and a second surface which are oppositely arranged, the silicon substrate is provided with a sunken structure extending from the first surface to the second surface, the sunken structure is columnar, and the first surface is provided with a first surface; according to the solar cell, the sunken structures extending from the first surface to the second surface are arranged, the sunken structures are columnar, light rays are almost not reflected when entering the sunken structures, the light trapping effect is optimal, absorption of sunlight is facilitated, and the light energy utilization capacity of the solar cell is improved.

Description

Technical Field

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

[0002] In the prior art, in order to reduce the light reflection on the surface of the solar cell and increase the light energy absorption, the surface of the solar cell is textured. Usually, before texturing the surface of the crystalline silicon cell, it is necessary to remove the impurities on the surface of the silicon wafer, eliminate the damaged layer on the surface of the silicon wafer, and perform polishing and leveling treatment, so that a pyramid-shaped velvet surface with the same size can be formed on the surface of the crystalline silicon cell. However, there is still a large light reflection effect on the surface of the existing crystalline silicon cell, and the light energy utilization is insufficient, which further affects the photoelectric conversion efficiency of the crystalline silicon cell. Summary of the Utility Model

[0003] This application provides a solar cell, aiming to solve the problem that there is still a large light reflection effect on the surface of the existing crystalline silicon cell, the light energy utilization is insufficient, and the photoelectric conversion efficiency of the crystalline silicon cell is affected.

[0004] This application is implemented as follows. A solar cell includes a silicon substrate, the silicon substrate has a first surface and a second surface arranged oppositely, the silicon substrate has a concave structure extending from the first surface towards the second surface, the concave structure is columnar, and a plurality of the concave structures are arranged at intervals.

[0005] Optionally, the ratio of the depth of the concave structure to the thickness of the silicon substrate is less than 10%.

[0006] Optionally, the depth of the concave structure is greater than 0 and less than or equal to 3 micrometers.

[0007] Optionally, at least some of the plurality of concave structures are arranged at equal intervals.

[0008] Optionally, at least some of the plurality of concave structures are arranged at unequal intervals.

[0009] Optionally, the spacing distance between adjacent concave structures is greater than 0 and less than or equal to 10 micrometers.

[0010] Optionally, the aperture range of the concave structure is greater than 2 and less than or equal to 20 micrometers.

[0011] Optionally, the cross-sectional shape of the concave structure is at least one of a circle, a polygon, and an ellipse.

[0012] Optionally, the cross-section of the concave structure is the same everywhere in the thickness direction of the silicon substrate.

[0013] Optionally, the reflectivity of the solar cell is less than 10%.

[0014] Optionally, the first surface is the front surface of the solar cell, and the second surface is the back surface of the solar cell.

[0015] In this application, a concave structure extending from the first surface towards the second surface is provided. The concave structure is columnar, and there is almost no reflection when light enters the concave structure, so the light trapping effect is optimal, which is beneficial to the absorption of sunlight and improves the light energy utilization ability of the solar cell.

[0016] A battery module includes the above-mentioned solar cell. The technical effects of this application are the same as those of the above-mentioned solar cell, and will not be elaborated here. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of the solar cell provided by the present application;

[0018] Figure 2 is a schematic diagram showing the distribution of the concave structure of the solar cell provided by the present application Figure 1 ;

[0019] Figure 3 is a schematic diagram showing the distribution of the concave structure of the solar cell provided by the present application Figure 2 ;

[0020] Figure 4 is a schematic diagram showing the distribution of the concave structure of the solar cell provided by the present application Figure 3 。

[0021] Description of the Reference Numerals:

[0022] 100, solar cell; 101, first surface; 102, second surface; 20, concave structure. Detailed Embodiments

[0023] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. Examples of the embodiments are shown in the 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 drawings are exemplary only for explaining the present application and should not be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0024] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the drawings. These terms are only used 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. Therefore, it should not be construed as a limitation to the present application.

[0025] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present application, "a plurality of" means two or more, unless otherwise specifically defined.

[0026] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, an electrical connection, or a connection capable of mutual communication; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0027] In the present application, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "over", and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "under", and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0028] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present application. In addition, the present application may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0029] As Figure 1 shown, a solar cell 100 includes a silicon substrate 10. The silicon substrate 10 serves as the support and foundation of the cell. The silicon substrate 10 has excellent semiconductor properties and mechanical stability. The material of the silicon substrate 10 can be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. Among them, the elemental semiconductor material can be in single crystal state, polycrystalline state, amorphous state or microcrystalline state (the state with both single crystal state and amorphous state is called microcrystalline state). For example, silicon can be at least one of single crystal silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon. Preferably, the silicon substrate 10 is made of n-type single crystal silicon.

[0030] The silicon substrate 100 has a first surface 101 and a second surface 102 which are oppositely arranged. In the embodiments of the present application, the first surface 101 and the second surface 102 can be the light-facing surface and the backlight surface of the silicon substrate 10 respectively. The light-facing surface can be understood as the side facing the sun when the solar cell 100 is installed, and the backlight surface can be understood as the side facing away from the sun when the solar cell 100 is installed. In some embodiments, the solar cell is a bifacial cell, that is, both the first surface 101 and the second surface 102 of the silicon substrate 10 can be used as the light-receiving surfaces and can be used to receive incident light. In the embodiments of the present application, the first surface is the front surface of the solar cell, and the second surface is the back surface of the solar cell.

[0031] As Figure 1As shown, the silicon substrate 10 has a recessed structure 20 extending from the first surface 101 towards the second surface 102. The recessed structure 20 is columnar. In particular, the cross-section of the recessed structure 20 in the thickness direction of the silicon substrate is the same everywhere, and multiple recessed structures 20 are arranged at intervals. In this application, a recessed structure 20 extending from the first surface 101 towards the second surface 102 is provided on the silicon substrate 10. The cross-section of the recessed structure 20 in the thickness direction of the silicon substrate is the same everywhere. It can be understood that the recessed structure 20 has a constant aperture in the thickness direction of the silicon substrate, and the inner sidewall of the recessed structure 20 is perpendicular to the surface of the silicon substrate 10. Compared with the conventional pyramid texture structure, light is directly reflected out at the inclined surface part of the pyramid, and there is almost no reflection when light enters the recessed structure 20. Even if part of the light is reflected when entering the inner sidewall of the recessed structure 20 at a certain angle, it can be absorbed during subsequent multiple reflection processes, and can be maximally absorbed and utilized by the silicon substrate, with the best light trapping effect, thereby improving the light energy utilization ability of the solar cell.

[0032] In some embodiments, the ratio of the depth of the recessed structure 20 to the thickness of the silicon substrate is less than 10%. For example, the ratio of the depth of the recessed structure 20 to the thickness of the silicon substrate can be 5%, 6%, 7%, 8%, 9%, etc. Preferably, the ratio of the depth of the recessed structure 20 to the thickness of the silicon substrate is greater than or equal to 8% and less than or equal to 10%. When the ratio of the depth of the recessed structure 20 to the thickness of the silicon substrate is within the above range, the best light trapping effect can be achieved. Even if part of the light is reflected when entering the inner sidewall of the recessed structure 20 at a certain angle, it can be absorbed during subsequent multiple reflection processes, achieving the effect that there is almost no reflection when light enters the recessed structure 20. And it can reduce the damage to the silicon substrate, and during the subsequent growth process of the passivation layer on the silicon substrate surface, a better passivation effect can be produced, forming a relatively smooth passivation layer.

[0033] In some embodiments, the depth of the recessed structure 20 is greater than 0 and less than or equal to 3 microns. Preferably, the depth of the recessed structure 20 is greater than or equal to 1 and less than or equal to 3 microns. Specifically, in such an embodiment, the depth of the recessed structure 20 can be 1μm, 1.5μm, 2μm, 2.5μm, 3μm or any value between 1μm - 3μm, and specific values are not limited here. The recessed structure 20 can be formed by using the method of reactive ion etching or mask wet etching. In addition, if the depth of the recessed structure 20 is too large, it is not easy to deposit the passivation layer into the recessed structure, resulting in a poor passivation effect.

[0034] As Figures 2 - 4As shown, in some embodiments, at least some of the plurality of recessed structures 20 are arranged at equal intervals. It can be understood that some of the plurality of recessed structures 20 can be arranged at equal intervals, and all of the plurality of recessed structures 20 can also be arranged at equal intervals. Such equally spaced recessed structures 20 can optimize the texture of the surface of the silicon substrate and further enhance the drag reduction effect of the silicon substrate. The arrangement of the recessed structures 20 can also reduce stress concentration and improve the reliability and stability of the solar cell.

[0035] As Figures 2 - 4 As shown, in other embodiments, at least some of the plurality of recessed structures 20 are arranged at unequal intervals. It can be understood that some of the plurality of recessed structures 20 can be arranged at unequal intervals, and all of the plurality of recessed structures 20 can also be arranged at unequal intervals. The unequally spaced recessed structures 20 can achieve a light trapping effect by adjusting the propagation path and reflection times of light. This effect can increase the absorption path of light in the silicon substrate, thereby improving the light absorption efficiency, which plays an important role in enhancing the performance of the solar cell. And the unequally spaced recessed structures 20 can form a non-uniform stress distribution on the silicon substrate, thereby effectively dispersing the impact and stress concentration of external forces on the silicon substrate. This structure can improve the mechanical strength and fatigue resistance of the silicon substrate and extend the service life of the silicon substrate.

[0036] The spacing distance between adjacent recessed structures 20 is greater than 0 and less than or equal to 10 microns. Preferably, the minimum spacing distance between adjacent recessed structures 20 is greater than or equal to 5 and less than or equal to 10 microns. Within this range, the minimum spacing distance between adjacent recessed structures 20 being greater than 0 ensures the physical separation between the plurality of recessed structures 20 and avoids the loss of the light trapping effect caused by the interconnection of the recessed structures 20; the minimum spacing distance between the plurality of recessed structures 20 being less than or equal to 10 microns can ensure that a sufficient number of recessed structures 20 are arranged per unit area on the silicon substrate, enhancing the light absorption ability of the silicon substrate surface, forming a fully black panel, and making the appearance more beautiful. The spacing distance of the recessed structures 20 affects the propagation path and reflection times of light. By precisely controlling the spacing distance, the light trapping effect can be improved, the absorption path of light in the silicon substrate can be increased, thereby improving the light absorption efficiency and the photoelectric conversion efficiency. If the spacing distance between adjacent recessed structures 20 is too large, the reflectivity is too high.

[0037] In other embodiments, it can be understood that the plurality of recessed structures 20 are spaced apart, and between the plurality of recessed structures 20 is a continuous polished surface structure. The continuous polished surface structure constitutes the base layer for the deposition and passivation of the silicon substrate, and ensuring a certain area of continuous polished surface structure facilitates the implementation of subsequent doping and passivation processes.

[0038] In some embodiments, the aperture of the recessed structure 20 ranges from greater than 2 and less than or equal to 20 microns. Preferably, the aperture of the recessed structure 20 is greater than or equal to 5 and less than or equal to 10 microns. Specifically, in such embodiments, the aperture of the recessed structure 20 can be 5μm, 6μm, 7μm, 8μm, 10μm, or any value between 5μm - 10μm, and specifically there is no limitation here. Setting the aperture of the recessed structure 20 within this range can, on the one hand, prevent the structure strength of the silicon substrate from being damaged by the setting of the recessed structure 20, and on the other hand, a better passivation film layer can be formed during the process of growing the passivation layer.

[0039] The cross-sectional shape of the recessed structure 20 is at least one of a circle, a polygon, and an ellipse. In other embodiments, the cross-sectional shape of the recessed structure 20 can also be a rectangle, a polygon, or a triangle. There is no limitation in this application and it can be flexibly set according to the process and processing requirements, as long as the aperture of the recessed structure 20 is consistent in the thickness direction of the silicon substrate, to avoid a large amount of direct reflection of the incident light by the inner sidewall of the recessed structure 20.

[0040] In some embodiments, the reflectivity of the solar cell is less than 10%. Compared with the reflectivity of the solar cell after texturing in the prior art, which is generally between 11% - 15%, the low reflectivity of the solar cell of this application means that a large amount of incident light is effectively absorbed and utilized for photoelectric conversion. This will lead to an increase in the photoelectric conversion efficiency and the effective utilization of energy. It can be understood that in other embodiments, further measures (such as depositing an antireflection thin film) can be taken to reduce the reflectivity of the silicon substrate to further improve the photoelectric conversion efficiency, and there is no limitation in this application.

[0041] A battery module includes the above-mentioned solar cell. Based on the above-mentioned solar cell, those skilled in the art know that by using multiple such solar cells and / or other corresponding existing accessories, the corresponding battery module can be obtained.

[0042] In the description of this specification, the description with reference to terms such as "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of this application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0043] The above are only the preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims

1. A solar cell, characterized in that: The invention comprises a silicon substrate, wherein the silicon substrate has a first surface and a second surface which are arranged opposite to each other, and the silicon substrate has a concave structure extending from the first surface toward the second surface, wherein the concave structure is columnar, and a plurality of the concave structures are arranged at intervals.

2. The solar cell according to claim 1, wherein: The ratio of the depth of the recessed structure to the thickness of the silicon substrate is less than 10%.

3. The solar cell according to claim 1, wherein: The depth of the recessed structure is greater than 0 and less than or equal to 3 micrometers.

4. The solar cell according to claim 1, wherein: At least some of the recessed structures are arranged at equal intervals.

5. The solar cell according to claim 1, wherein: At least some of the multiple recessed structures are arranged at unequal intervals.

6. The solar cell according to claim 1, wherein: The spacing distance between adjacent recessed structures is greater than 0 and less than or equal to 10 micrometers.

7. The solar cell according to claim 1, wherein: The aperture of the recessed structure is in the range of greater than 2 and less than or equal to 20 micrometers.

8. The solar cell according to claim 1, wherein: The cross-section of the recessed structure is in at least one of a circular, polygonal and elliptical shape.

9. The solar cell according to claim 1, wherein: The cross section of the recessed structure in the thickness direction of the silicon substrate is the same everywhere.

10. The solar cell according to claim 1, wherein: The reflectivity of the solar cell is less than 10%.

11. The solar cell according to claim 1, wherein: The first surface is the front side of the solar cell, and the second surface is the back side of the solar cell.

12. A battery assembly, characterized in that: A solar cell comprising any one of claims 1 to 11.

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