Hit solar cell and cell module

Abstract

The present invention relates to the technical field of solar cells. Disclosed are an HIT solar cell and a cell module. The HIT solar cell comprises a silicon substrate, wherein the silicon substrate has two side surfaces that are oppositely arranged in the thickness direction of the silicon substrate; on each of the two side surfaces, an a-Si:H layer, a TCO film layer and a passivation layer are sequentially arranged outwards from the silicon substrate in the thickness direction; and a metal electrode is further protrudingly arranged on the side of each passivation layer away from the silicon substrate in the thickness direction. The present invention can improve an adhesion force between a cell and a module encapsulant film, and can improve the connection of electrode grid lines; in addition, a passivation layer is used to form three graded refractive index layers together with a TCO film layer and an amorphous silicon layer, thereby effectively reducing optical losses in the power generation process of cells.

Description

HIT solar cells and battery modules Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a HIT solar cell and a cell assembly. Background Art

[0002] HIT (Heterojunction with Intrinsic Thin-layer) is known in Chinese as a heterojunction cell, and its full name is "crystalline silicon heterojunction solar cell." The current mainstream HIT cell structure in the industry is silver electrode-TCO thin film-a-Si:H(P+) layer-a-Si:H(i) layer-N-type silicon substrate-a-Si:H(i) layer-a-Si:H(N+) layer-TCO thin film-silver electrode. This cell has advantages such as high open-circuit voltage and low efficiency drop at the module end. However, it also has the following disadvantages:

[0003] 1. Poor adhesion between TCO film and module end film;

[0004] 2. The refractive index gradient only has two layers: TCO film and amorphous silicon. Summary of the Invention

[0005] The purpose of the present invention is to design a HIT solar cell and a cell assembly that can solve the above problems.

[0006] To achieve the above-mentioned object, the present invention provides a HIT solar cell, comprising: a silicon substrate, the silicon substrate having two side surfaces arranged opposite to each other along its thickness direction, the two side surfaces being provided with an a-Si:H layer, a TCO film layer, and a passivation layer in sequence outwardly along the silicon substrate in the thickness direction, and each of the passivation layers being provided with a metal electrode protruding from a side facing away from the silicon substrate in the thickness direction.

[0007] Furthermore, the passivation layer is an oxide layer or silicon nitride.

[0008] Furthermore, a through groove communicating with the TCO film layer is provided on the passivation layer, and the metal electrode is provided on the through groove and connected to the TCO film layer through the through groove.

[0009] Furthermore, it includes a plurality of the metal electrodes, which are arranged in sequence along the length direction of the silicon substrate at intervals, and a plurality of through grooves are spaced apart on the passivation layer along the length direction, and each of the metal electrodes is arranged in each of the through grooves in a one-to-one correspondence.

[0010] Furthermore, the outer wall of the metal electrode abuts against the groove wall of the through groove.

[0011] Furthermore, the metal electrode is a silver electrode or a silver-aluminum electrode.

[0012] Furthermore, the metal electrode is an electroplated copper electrode.

[0013] Further, the two a-Si:H layers are respectively defined as a first layer and a second layer, the first layer includes a first a-Si:H(i) layer and an a-Si:H(P+) layer stacked in the thickness direction, and the first a-Si:H(i) layer is located on the side of the a-Si:H(P+) layer facing the silicon substrate; the second layer includes a second a-Si:H(i) layer and an a-Si:H(N+) layer stacked in the thickness direction, and the second a-Si:H(i) layer is located on the side of the a-Si:H(N+) layer facing the silicon substrate.

[0014] Furthermore, the dimension of the a-Si:H(P+) layer in the thickness direction is 15 mm to 25 mm.

[0015] The present invention also provides a HIT solar cell assembly, comprising the above-mentioned HIT solar cell.

[0016] Compared with the prior art, the HIT solar cell and battery assembly according to the embodiment of the present invention have the following advantages:

[0017] The HIT solar cell and cell assembly of the embodiments of the present invention have a passivation layer that can improve the adhesion between the cell structure and the adhesive film. At the same time, the passivation layer, TCO film layer and a-Si:H layer are combined to form a gradient refractive layer, which effectively reduces optical loss during the cell power generation process. The use of an electroplated metal electrode process greatly reduces product costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a cross-sectional view of a HIT solar cell according to an embodiment of the present invention;

[0019] FIG2 is a cross-sectional view of a HIT solar cell according to another embodiment of the present invention.

[0020] In the figure, 1. silicon substrate; 2. a-Si:H layer; 21. first layer; 211. first a-Si:H(i) layer; 212. a-Si:H(P+) layer; 22. second layer; 221. second a-Si:H(i) layer; 222. a-Si:H(N+) layer; 3. TCO film layer; 4. passivation layer; 41. through groove; 5. metal electrode; x, thickness direction; y, length direction. DETAILED DESCRIPTION

[0021] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0022] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" used in the present invention to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] In the description of the present invention, it should be understood that the terms "connected," "connected," "fixed," etc. used in the present invention should be interpreted broadly. For example, the terms may be fixedly connected, detachably connected, or integrated; may be mechanically connected or welded; may be directly connected or indirectly connected through an intermediate medium; may be internal communication between two elements or an interactive relationship between two elements, unless otherwise clearly defined. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] The present invention uses terms such as "first" and "second" to describe various types of information, but the information should not be limited to these terms. These terms are used only to distinguish information of the same type from each other. For example, "first" information can also be referred to as "second" information, and similarly, "second" information can also be referred to as "first" information without departing from the scope of the present invention.

[0025] In this description, the thickness of a HIT solar cell is defined as the thickness direction, and the length of the HIT solar cell is defined as the length direction. The thickness direction and the length direction are perpendicular to each other, and errors may occur in actual applications. In the HIT solar cell structure, the thickness direction is closer to the silicon substrate and the thickness direction is farther from the silicon substrate.

[0026] As shown in FIG1 , a HIT solar cell according to a preferred embodiment of the present invention comprises: a silicon substrate 1 having two side surfaces opposite to each other along a thickness direction x thereof, wherein both side surfaces are provided with an a-Si:H layer 2, a TCO film layer 3, and a passivation layer 4 in sequence outwardly along the silicon substrate 1 in the thickness direction x, and each of the passivation layers 4 is further provided with a metal electrode 5 protruding from a side facing away from the silicon substrate 1 in the thickness direction x.

[0027] The TCO film layer 3 is a thin TCO film, and the a-Si:H layer 2 is an amorphous silicon layer. A passivation layer 4 is provided on the outer surface of the TCO film layer 3 to optimize the adhesion between the cell structure and the module end film. Specifically, the silicon substrate 1 can be an N-type silicon substrate. The refractive index of the passivation layer 4 is approximately 1.5, the refractive index of the TCO film layer 3 is approximately 2.1, and the refractive index of the a-Si:H layer 2 (amorphous silicon layer) is approximately 3.3. These three layers form a gradient refractive index layer, which effectively reduces optical losses during the cell power generation process.

[0028] In some improved solutions of the present application, the passivation layer 4 is an oxide layer or silicon nitride.

[0029] As shown in Figure 2, since the addition of a functional passivation layer 4 on the TCO film will increase the contact resistance between the metal electrode 5 and the battery, in some improved solutions of the present application, a through groove 41 connected to the TCO film layer 3 is opened on the passivation layer 4, and the metal electrode 5 is arranged on the through groove 41 and directly connected to the TCO film layer 3 through the through groove 41 to avoid affecting its contact resistance.

[0030] In some improved solutions of the present application, a plurality of metal electrodes 5 are provided, spaced apart in sequence along the length direction y of the silicon substrate 1. A plurality of through-grooves 41 are provided on the passivation layer 4 at intervals along the length direction y, and each metal electrode 5 is disposed in a corresponding through-grooves 41. This allows the metal electrodes 5 to directly contact the TCO film layer 3, thereby avoiding affecting the contact between the metal electrodes 5 and the battery structure.

[0031] In some improved solutions of the present application, the outer wall of the metal electrode 5 abuts against the groove wall of the through groove 41, so that the passivation layer 4 plays the role of fixing the metal electrode 5 and avoiding problems such as gate detachment.

[0032] In some improved solutions of the present application, the metal electrode 5 is a silver electrode or a silver-aluminum electrode, which can be prepared by screen printing technology, which has good repeatability and high preparation efficiency.

[0033] In some improved solutions of the present application, the metal electrode 5 is an electroplated copper electrode. Using the electroplating copper process to manufacture the metal electrode 5 can reduce costs and improve the adhesion between the metal electrode 5 and the TCO film layer 3. It should be noted that other types of metal conductive materials can also be electroplated to replace the current printed silver electrode, greatly reducing costs.

[0034] In some improved schemes of the present application, the two a-Si:H layers 2 are defined as a first layer 21 and a second layer 22, respectively. The first layer 21 includes a first a-Si:H(i) layer 211 and an a-Si:H(P+) layer 212 stacked in the thickness direction x, and the first a-Si:H(i) layer 211 is located on the side of the a-Si:H(P+) layer 212 facing the silicon substrate 1; the second layer 22 includes a second a-Si:H(i) layer 221 and an a-Si:H(N+) layer 222 stacked in the thickness direction x, and the second a-Si:H(i) layer 221 is located on the side of the a-Si:H(N+) layer 222 facing the silicon substrate 1. The first a-Si:H(i) layer 211 and the second a-Si:H(i) layer 221 are both intrinsic non-gold silicon layers, the a-Si:H(P+) layer 212 is a P-type amorphous silicon layer, and the a-Si:H(N+) layer 222 is an amorphous silicon layer.

[0035] In some improved solutions of the present application, the dimension of the a-Si:H(P+) layer 212 in the thickness direction x is 15 mm to 25 mm.

[0036] The present invention also provides a HIT solar cell assembly, comprising the HIT solar cell structure in the above solution.

[0037] In summary, the embodiments of the present invention provide a HIT solar cell and a battery assembly, which have the following advantages:

[0038] 1. A new passivation layer 4 is provided on the front and back surfaces of the battery to optimize the adhesion between the battery structure and the component end film;

[0039] 2. The passivation layer 4 with a refractive index of 1.5, the TCO film layer 3 with a refractive index of 2.1 and the a-Si:H layer 2 with a refractive index of 3.3 are combined to form a three-layer gradient refractive layer, which can effectively reduce the optical loss during the battery power generation process;

[0040] 3. Use copper electroplating process to make metal electrodes 5 to reduce costs;

[0041] 4. The passivation layer 4 is provided with a groove 41 at the connection between the electrode and the TCO film 3, which can fix the metal electrode 5 and avoid problems such as gate detachment.

[0042] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A HIT solar cell, characterized in that: include: A silicon substrate, wherein the silicon substrate has two side surfaces arranged opposite to each other along its thickness direction, and the two side surfaces are sequentially provided with an a-Si:H layer, a TCO film layer and a passivation layer along the silicon substrate outward in the thickness direction, and each of the passivation layers is also protrudingly provided with a metal electrode on the side away from the silicon substrate in the thickness direction.

2. The HIT solar cell according to claim 1, characterized in that: The passivation layer is an oxide layer or silicon nitride.

3. The HIT solar cell according to claim 1, characterized in that: The passivation layer is provided with a through groove connected to the TCO film layer, and the metal electrode is arranged on the through groove and connected to the TCO film layer through the through groove.

4. The HIT solar cell according to claim 3, characterized in that: It comprises a plurality of metal electrodes, which are arranged in sequence along the length direction of the silicon substrate at intervals, and a plurality of through grooves are arranged on the passivation layer along the length direction at intervals, and each of the metal electrodes is arranged in each of the through grooves in a one-to-one correspondence.

5. The HIT solar cell according to claim 3, characterized in that: The outer wall of the metal electrode abuts against the groove wall of the through groove.

6. The HIT solar cell according to claim 1, wherein: The metal electrode is a silver electrode or a silver-aluminum electrode.

7. The HIT solar cell according to claim 1, characterized in that: The metal electrode is an electroplated copper electrode.

8. The HIT solar cell according to claim 1, wherein: The two a-Si:H layers are defined as a first layer and a second layer, respectively. The first layer includes a first a-Si:H(i) layer and an a-Si:H(P+) layer stacked in the thickness direction, and the first a-Si:H(i) layer is located on the side of the a-Si:H(P+) layer facing the silicon substrate; the second layer includes a second a-Si:H(i) layer and an a-Si:H(N+) layer stacked in the thickness direction, and the second a-Si:H(i) layer is located on the side of the a-Si:H(N+) layer facing the silicon substrate.

9. The HIT solar cell according to claim 8, characterized in that: The dimension of the a-Si:H(P+) layer in the thickness direction is 15 mm to 25 mm.

10. A HIT solar cell module, characterized in that: The method comprises the HIT solar cell according to any one of claims 1 to 9.

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