Solar cell electrode structure, solar cell and photovoltaic module

Abstract

The utility model relates to a solar cell electrode structure, a solar cell and a photovoltaic module. The solar cell electrode structure comprises a metal substrate layer and a metal reflecting layer. The metal substrate layer is arranged on the surface of the solar cell body, and the metal reflecting layer is arranged on the surface, away from the solar cell body, of the metal substrate layer. The metal reflecting layer comprises a protruding part, and the radial width of the protruding part is gradually reduced from the bottom end of the protruding part to the top end of the protruding part. The solar cell electrode structure is provided with the metal reflecting layer arranged on the surface of the metal base material layer, the metal reflecting layer comprises the protruding part with the radial width gradually narrowed from the bottom end to the top end, and when sunlight enters the surface of the protruding part, the protruding part can reflect the incident sunlight downwards, so that the sunlight is reflected to the surface of the metal base material layer. Therefore, total reflection of sunlight incident to the surface of the solar cell electrode is reduced, and the optical utilization rate of the solar cell is improved.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a solar cell electrode structure, a solar cell and a photovoltaic module. Background Art

[0002] Copper electroplating interconnection solar cell technology is a cost-reducing method for metallization of solar cells. It uses copper electroplating interconnection to prepare copper grid electrodes instead of traditional silver electrodes formed by screen printing silver paste, which can significantly reduce the metallization costs associated with expensive silver paste for screen printing. Copper electroplating interconnection to prepare grid electrodes is one of the hot technologies in the photovoltaic industry. However, the grid lines formed on the surface of the cell by copper electroplating technology are relatively flat, and traditional metal grid lines are prone to total reflection of incident sunlight, resulting in low optical utilization of the cell. Utility Model Content

[0003] Based on this, it is necessary to provide a solar cell electrode structure, a solar cell and a photovoltaic module. The solar cell electrode structure of the present application can reduce the total reflection of sunlight incident on the surface of the solar cell electrode and improve the optical utilization rate of the solar cell.

[0004] In a first aspect, the present application provides a solar cell electrode structure, comprising a metal substrate layer and a metal reflective layer;

[0005] The metal substrate layer is arranged on the surface of the solar cell body, and the metal reflective layer is arranged on the surface of the metal substrate layer away from the solar cell body;

[0006] The metal reflective layer includes a protrusion, and the radial width of the protrusion gradually narrows from the bottom end of the protrusion to the top end thereof.

[0007] In some embodiments, the metal reflective layer includes a plurality of protrusions, and the plurality of protrusions are arranged at intervals on the surface of the metal substrate layer.

[0008] In some embodiments, at least a portion of the outer surface of the protrusion is a curved surface.

[0009] In some embodiments, the solar cell electrode structure further includes a metal protective layer, which covers the surface of the metal substrate layer away from the solar cell body, and the protrusion is arranged on the surface of the metal protective layer away from the solar cell body.

[0010] In some embodiments, the metal protection layer also covers the side surfaces of the metal substrate layer.

[0011] In some embodiments, the metal substrate layer is a copper substrate layer.

[0012] In some embodiments, the metal protective layer is a tin protective layer.

[0013] In some embodiments, the metal reflective layer is a tin reflective layer.

[0014] In some embodiments, the solar cell electrode structure further includes a metal intermediate layer, wherein the metal intermediate layer is disposed between the metal protective layer and the metal substrate layer, and the metal intermediate layer is a zinc alloy intermediate layer.

[0015] In some embodiments, the width of the metal substrate layer is 20 μm to 50 μm.

[0016] In some embodiments, the thickness of the metal substrate layer is 3 μm to 20 μm.

[0017] In a second aspect, the present application provides a solar cell comprising any of the solar cell electrode structures described above.

[0018] In a third aspect, the present application provides a photovoltaic module, comprising the above-mentioned solar cell.

[0019] The above-mentioned solar cell electrode structure has a metal reflective layer arranged on the surface of the metal substrate layer, and the metal reflective layer includes a protrusion whose radial width gradually narrows from the bottom end to the top end. When sunlight is incident on the surface of the protrusion, the protrusion can reflect the incident sunlight downward, thereby reducing the total reflection of sunlight incident on the surface of the solar cell electrode and improving the optical utilization rate of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is a schematic diagram of a solar cell electrode structure provided by an embodiment of the present application;

[0021] FIG2 is a schematic diagram of a solar cell electrode structure provided by another embodiment of the present application;

[0022] FIG3 is a schematic diagram of light path simulation paths for electrode surfaces of different morphologies, wherein (a) is a light path simulation path for a regular electrode surface, and (b) is a light path simulation path for an irregular electrode surface;

[0023] FIG4 is an optical microscope image of electrode surfaces of different morphologies, wherein (a) is an optical microscope image of a regular electrode surface, and (b) is an optical microscope image of an irregular electrode surface.

[0024] Description of Reference Numerals

[0025] 10. Metal substrate layer; 20. Metal protective layer; 30. Metal reflective layer; 31. Raised portion; 40. Metal intermediate layer. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0028] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0029] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0030] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0031] As shown in FIG1 , the present application provides a solar cell electrode structure, comprising a metal substrate layer 10 and a metal reflective layer 30. The metal substrate layer 10 is disposed on the surface of the solar cell body, and the metal reflective layer 30 is disposed on the surface of the metal substrate layer 10 away from the solar cell body. The metal reflective layer 30 comprises a protrusion 31, and the radial width of the protrusion 31 gradually narrows from the bottom end of the protrusion 31 to the top end thereof.

[0032] The above-mentioned solar cell electrode structure has a metal reflective layer 30 arranged on the surface of the metal substrate layer 10, and the metal reflective layer 30 includes a protrusion 31 whose radial width gradually narrows from the bottom end to the top end. When sunlight is incident on the surface of the protrusion 31, the protrusion 31 can reflect the incident sunlight downward, thereby reducing the total reflection of sunlight incident on the surface of the solar cell electrode and improving the optical utilization rate of the solar cell.

[0033] For ease of understanding, please refer to FIG. 3, which is a schematic diagram of the light path simulation path of electrode surfaces with different morphologies, wherein a is the light path simulation path of a regular electrode surface, and b is the light path simulation path of an irregular electrode surface. It can be seen that when sunlight is incident on the relatively flat surface of a traditional solar cell electrode, total reflection of sunlight is more likely to occur. When sunlight is incident on the surface of the protrusion 31, since the radial width of the protrusion 31 gradually narrows from the bottom end of the protrusion 31 to the top end thereof, the surface of the protrusion 31 will reflect the incident light at different angles according to the position of the surface of the protrusion 31 where the incident light is incident, and part of the sunlight will be irradiated onto the surface of the solar cell body after reflection, thereby being absorbed by the solar cell body, thereby improving the optical utilization rate of the solar cell.

[0034] In some embodiments, the metal reflective layer 30 includes a plurality of protrusions 31 , and the plurality of protrusions 31 are arranged on the surface of the metal substrate layer 10 at intervals.

[0035] The plurality of protrusions 31 are arranged at intervals on the surface of the metal substrate layer 10 , which can increase the effective reflection of sunlight incident on the protrusions 31 , reduce the total reflection of sunlight incident on the surface of the solar cell electrode, and improve the optical utilization rate of the solar cell.

[0036] In some embodiments, at least a portion of the outer surface of the protrusion 31 is a curved surface.

[0037] At least part of the outer surface of the raised portion 31 is a curved surface, which enables sunlight incident on different positions of the outer surface of the raised portion 31 to have different reflection angles. Part of the sunlight will irradiate the surface of the solar cell body after reflection, and then be absorbed by the solar cell body, thereby improving the optical utilization rate of the solar cell.

[0038] In some embodiments, the protrusion 31 has a hemispherical structure.

[0039] After the cell package with the above-mentioned solar cell electrode structure supports the photovoltaic module, the front of the solar cell is usually packaged by a glass cover. The surface of the hemispherical protrusion 31 is more likely to form multiple reflections of the light path. As shown in Figure 3, when the angle between the light reflected by the protrusion 31 and the surface of the battery body is 22.5°~45°, the light can form a total reflection effect on the glass surface, which can make the light have a higher utilization rate inside the photovoltaic module.

[0040] 1 , in some embodiments, the solar cell electrode structure further includes a metal protective layer 20, which covers the surface of the metal substrate layer 10 away from the solar cell body, and the protrusion 31 is arranged on the surface of the metal protective layer 20 away from the solar cell body.

[0041] It is understandable that, in order to save costs, the metal substrate layer 10 is usually a copper substrate layer produced by electroplating. A metal protective layer 20 is provided on the surface of the copper substrate, and the metal protective layer 20 is mainly used to isolate the copper substrate layer from the outside air, prevent oxidation of the copper substrate layer, and prevent copper ions from diffusing to other locations, resulting in reduced reliability of the battery cell.

[0042] In some embodiments, the metal protection layer 20 also covers the side surfaces of the metal substrate layer 10 .

[0043] The metal protection layer 20 is mainly used to isolate the copper substrate layer from the outside air, to prevent the copper substrate layer from being oxidized and to prevent copper ions from diffusing to other locations, which would reduce the reliability of the battery cell.

[0044] In some embodiments, the metal substrate layer 10 is a copper substrate layer.

[0045] In some embodiments, the metal protective layer 20 is a tin protective layer.

[0046] In some embodiments, the metal reflective layer 30 is a tin reflective layer.

[0047] For the solar cell electrode structure having the above structure, it is convenient to prepare the raised portion 31 of the metal reflective layer 30 through the electroplating process. It should be noted that the raised portion 31 of the metal reflective layer 30 can be prepared by the following preparation method: after electroplating a copper substrate layer as the metal substrate layer 10, electroplating a tin protective layer on the surface of the metal substrate layer 10 as the metal protective layer 20; while electroplating a small amount of copper to prepare the tin protective layer, the high-temperature solidification point of the tin protective layer is inconsistent and agglomerates are formed, thereby forming the raised portion 31 of the tin reflective layer located on the surface of the tin protective layer. It can be understood that the tin agglomeration can form an irregular hemispherical raised portion 31.

[0048] The raised portion 31 of the metal reflective layer 30 can also be prepared by the following preparation method: after electroplating a copper substrate layer as the metal substrate layer 10, electroplating a tin protective layer on the surface of the metal substrate layer 10 as the metal protective layer 20, when electroplating the tin protective layer, the tin protective layer can be made non-wettable by electroplating solution formulation or additives, and the metal tin on the surface of the tin protective layer can be controlled by controlling the process temperature to control the agglomeration of metal tin, thereby forming the metal reflective layer 30 with the raised portion 31. It should be noted that the temperature at which the tin protective layer produces non-wetting is 220°C to 260°C.

[0049] 2 , in some embodiments, the solar cell electrode structure further includes a metal intermediate layer 40 , which is disposed between the metal protective layer 20 and the metal substrate layer 10 , and the metal intermediate layer 40 is a zinc alloy intermediate layer.

[0050] The solar cell electrode structure with the above structure is convenient for preparing the raised portion 31 of the metal reflective layer 30 through the electroplating process. It should be noted that the raised portion 31 of the metal reflective layer 30 can be prepared by the following preparation method: after electroplating a copper substrate layer as the metal substrate layer 10, electroplating a zinc alloy intermediate layer on the surface of the metal substrate layer 10 as the metal intermediate layer 40, and then electroplating a tin protective layer on the surface of the metal intermediate layer 40 as the metal protective layer 20; after the preparation is completed, the electrode is baked at a high temperature. Since the melting point of tin is lower than the baking temperature of the zinc alloy, when the temperature rises, the tin will melt first and form a layer of liquid tin on the surface. At this time, due to the effect of surface tension, the liquid tin will agglomerate, thereby forming the raised portion 31 of the tin reflective layer located on the surface of the tin protective layer.

[0051] In some embodiments, the width of the metal substrate layer 10 is 20 μm to 50 μm.

[0052] 1 , illustratively, the X direction in FIG. 1 is the width direction of the metal substrate layer 10. Optionally, the width of the metal substrate layer 10 is 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, 32 μm, 34 μm, 36 μm, 38 μm, 40 μm, 42 μm, 44 μm, 46 μm, 48 μm or 50 μm. Alternatively, the width of the metal substrate layer 10 may also be within the range between any two of the above widths.

[0053] In some embodiments, the thickness of the metal substrate layer 10 is 3 μm to 20 μm.

[0054] 1 , exemplarily, the Y direction in FIG. 1 is the thickness direction of the metal substrate layer 10. Optionally, the thickness of the metal substrate layer 10 is 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 1.5 μm, 16 μm, 16.5 μm, 17 μm, 17.5 μm, 18 μm, 18.5 μm, 19 μm, 19.5 μm or 20 μm. Alternatively, the thickness of the metal substrate layer 10 may also be within the range between any two of the above thicknesses.

[0055] Referring to FIG. 4 , FIG. 4 is an optical microscope image of electrode surfaces of different morphologies, wherein a is an optical microscope image of a regular electrode surface, and b is an optical microscope image of an irregular electrode surface.

[0056] In some embodiments, the solar cell electrode structure includes a metal substrate layer 10 and a metal reflective layer 30. The metal substrate layer 10 is disposed on the surface of the solar cell body, and the metal reflective layer 30 is disposed on the surface of the metal substrate layer 10 away from the solar cell body. The metal reflective layer 30 includes a protrusion 31, and the radial width of the protrusion 31 gradually narrows from the bottom end of the protrusion 31 to the top end thereof. The metal reflective layer 30 includes a plurality of protrusions 31, and the plurality of protrusions 31 are arranged at intervals on the surface of the metal substrate layer 10. At least part of the outer surface of the protrusion 31 is a curved surface. The solar cell electrode structure also includes a metal protective layer 20, which covers the surface of the metal substrate layer 10 away from the solar cell body, and the protrusion 31 is disposed on the surface of the metal protective layer 20 away from the solar cell body. The metal protective layer 20 also covers the side of the metal substrate layer 10. The metal substrate layer 10 is a copper substrate layer, the metal protective layer 20 is a tin protective layer, and the metal reflective layer 30 is a tin reflective layer.

[0057] Yet another embodiment of the present application provides a solar cell, comprising any of the above-mentioned solar cell electrode structures.

[0058] In some embodiments, the solar cell includes a silicon substrate having a front side and a back side arranged opposite to each other. The front side of the silicon substrate is sequentially stacked with a semiconductor layer and the above-mentioned solar cell electrode structure, and the semiconductor layer and the silicon substrate have opposite doping types. The back side of the silicon substrate is provided with a back electrode.

[0059] Yet another embodiment of the present application provides a photovoltaic module, comprising the above-mentioned solar cell.

[0060] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0061] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims, and the description and drawings may be used to interpret the contents of the claims.

Claims

1. A solar cell electrode structure, characterized in that: It comprises a metal substrate layer (10) and a metal reflective layer (30); The metal substrate layer (10) is arranged on the surface of the solar cell body, and the metal reflective layer (30) is arranged on the surface of the metal substrate layer (10) away from the solar cell body; The metal reflective layer (30) comprises a protruding portion (31), and the radial width of the protruding portion (31) gradually narrows from the bottom end of the protruding portion (31) towards the top end thereof.

2. The solar cell electrode structure according to claim 1, characterized in that: The metal reflective layer (30) comprises a plurality of protrusions (31), and the plurality of protrusions (31) are arranged at intervals on the surface of the metal substrate layer (10).

3. The solar cell electrode structure according to claim 1, characterized in that: At least part of the outer surface of the raised portion (31) is a curved surface.

4. The solar cell electrode structure according to claim 1, characterized in that: The solar cell electrode structure further comprises a metal protective layer (20), wherein the metal protective layer (20) covers a surface of the metal substrate layer (10) away from the solar cell body, and the protrusion (31) is arranged on a surface of the metal protective layer (20) away from the solar cell body.

5. The solar cell electrode structure according to claim 4, characterized in that: The metal protective layer (20) also covers the side surfaces of the metal substrate layer (10).

6. The solar cell electrode structure according to claim 4, characterized in that: The metal substrate layer (10) is a copper substrate layer; And / or, the metal protective layer (20) is a tin protective layer; And / or, the metal reflective layer (30) is a tin reflective layer.

7. The solar cell electrode structure according to claim 4, characterized in that: The solar cell electrode structure further comprises a metal intermediate layer (40), wherein the metal intermediate layer (40) is arranged between the metal protective layer (20) and the metal substrate layer (10), and the metal intermediate layer (40) is a zinc alloy intermediate layer.

8. The solar cell electrode structure according to any one of claims 1 to 7, characterized in that: The width of the metal substrate layer (10) is 20 μm to 50 μm; and / or, The thickness of the metal substrate layer (10) is 3 μm to 20 μm.

9. A solar cell, characterized in that: The invention comprises the solar cell electrode structure as described in any one of claims 1 to 8.

10. A photovoltaic module, characterized in that: Comprising the solar cell as claimed in claim 9.

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