A photovoltaic cell stack with a composite metal electrode layer

Abstract

The utility model discloses a photovoltaic cell set with composite metal electrode layer, include: cell piece, the cell piece is provided with a plurality, is provided with composite metal electrode layer at the front and / or back of cell piece, the composite metal electrode layer includes tin electrode layer, the triangle conductive silk one end and the tin electrode layer abuts at one cell piece, the other end and the tin electrode layer abut at another cell piece, and the triangle conductive silk can connect two adjacent cell pieces. Through setting tin electrode layer directly on the surface of cell piece, in the welding process of triangle conductive silk and tin electrode layer, tin electrode layer and triangle conductive silk are welded together directly. Tin electrode layer not only plays the role of conducting electricity, still plays the role of and triangle conductive silk connection fixed role, need not extra tin paste coating, has solved the problem that tin paste coating amount is not easy to control.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic cells, specifically to a photovoltaic cell pack with a composite metal electrode layer. Background Technology

[0002] In recent years, in addition to developing solar cells, the coordination of modules has become increasingly important in the photovoltaic industry. Among them, the production of stacked grid cells / modules is one of the important directions for cost reduction and efficiency improvement in photovoltaic solar cells. The essence is the use of triangular conductive wires, which can reflect sunlight blocked by the conductive wires back to the solar cells through the reflective side of the triangular conductive wires, thereby maximizing the utilization of reflected light to improve photoelectric conversion efficiency.

[0003] However, solder paste needs to be applied to the contact surface between the triangular conductive wires and the solar cell to bond the two components. However, the triangular conductive wires have a linewidth range of only 30-100μm, making it difficult to ensure even and uniform adhesion while preventing wire flipping. Furthermore, controlling the amount of solder paste applied is challenging. Too much paste can cause diffusion, resulting in light obstruction; too little paste can cause the triangular conductive wires to detach from the solar cell, affecting the reliability of the battery module. Utility Model Content

[0004] To overcome the above-mentioned shortcomings, the purpose of this utility model is to provide a photovoltaic cell pack with a composite metal electrode layer on the contact surface between the cell and the triangular conductive wire. By preparing the tin connection layer on the cell, it is not necessary to adhere solder paste to the contact surface of the triangular conductive wire, thus solving the problems of difficulty in controlling the amount of solder paste and the flipping of the conductive wire.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is: a photovoltaic cell module with a composite metal electrode layer, comprising:

[0006] A battery cell, wherein multiple battery cells are provided, and a composite metal electrode layer is provided on the front and / or back of the battery cell, the composite metal electrode layer including a tin electrode layer;

[0007] A triangular conductive wire, one end of which abuts against the tin electrode layer of one battery cell, and the other end of which abuts against the tin electrode layer of another battery cell, is used to connect two adjacent battery cells.

[0008] By directly depositing a tin electrode layer on the surface of the solar cell, the tin electrode layer and the triangular conductive wire are directly welded together during the welding process. The tin electrode layer not only serves to conduct electricity but also to connect and fix the triangular conductive wire. Furthermore, it eliminates the need for additional solder paste adhering to the contact surface of the triangular conductive wire, thus solving the problems of difficult-to-control solder paste application and the issue of conductive wire flipping.

[0009] Furthermore, the composite metal electrode layer includes a metal silicon alloy layer.

[0010] Furthermore, the metal-silicon alloy layer is formed by sintering a metal bonding layer and a poly layer. The poly layer (Polysilicon Layer) is a polycrystalline silicon layer.

[0011] Furthermore, the metal silicon alloy layer is a nickel-silicon alloy layer.

[0012] Furthermore, the metal bonding layer abuts against the n-poly layer or p-poly layer of the battery cell, and the material of the metal bonding layer is selected from a single metal such as nickel, tungsten, or titanium, or a nickel, tungsten, or titanium alloy, and the thickness of the metal bonding layer is 0.05 μm to 2 μm.

[0013] Furthermore, the material of the metal bonding layer is nickel.

[0014] Furthermore, the tin electrode layer and the silicon metal alloy layer abut against each other, and the tin electrode layer is located on the side of the silicon metal alloy layer away from the solar cell.

[0015] Furthermore, the thickness of the tin electrode layer is 0.5 μm to 5 μm.

[0016] Furthermore, a passivation layer is provided on the front and / or back of the solar cell, and an opening is formed on the passivation layer by an etching process. The opening is used to accommodate a composite metal electrode layer prepared by an electroplating process. The tin electrode layer is prepared by an electroplating process, and the thickness of the tin electrode layer can be precisely controlled according to requirements.

[0017] Furthermore, the composite metal electrode layer consists of a nickel-silicon alloy layer and a tin electrode layer. The tin electrode layer is deposited on the surface of the nickel-silicon alloy layer through an electroplating process, and the tin electrode abuts against the triangular conductive wire. By directly electroplating the tin electrode layer onto the nickel-silicon alloy layer, there is no need to additionally set a copper electrode layer. The tin electrode layer replaces the copper electrode layer, providing conductivity, and also replaces solder paste, serving to adhere the battery cells and triangular conductive wire. This not only solves the problem of difficult control of solder paste adhesion on the contact surface of the triangular conductive wire connection, but also simplifies the number of electrode layers and the battery pack manufacturing process. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram illustrating the partial removal of the outermost passivation layer of the battery cell in Example 1;

[0021] Figure 2 This is a schematic diagram of the preparation of a silicon metal alloy layer at the opening in Example 1;

[0022] Figure 3 This is a schematic diagram of the tin electrode layer fabrication in Example 1;

[0023] Figure 4 This is a schematic diagram illustrating the partial removal of the passivation layer on the back of the battery cell in Example 2;

[0024] Figure 5 This is a schematic diagram of the preparation of a silicon metal alloy layer at the opening in Example 2;

[0025] Figure 6 This is a schematic diagram of the tin electrode layer fabrication in Example 2;

[0026] In the diagram: 1. Solar cell; 2. p-poly layer; 3. n-poly layer; 4. Passivation layer; 5. Opening; 6. Metal-silicon alloy layer; 7. Tin electrode layer. Detailed Implementation

[0027] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0028] A photovoltaic cell array with a composite metal electrode layer includes multiple cells 1, wherein the multiple cells are two or more cells. A composite metal electrode layer is disposed on the front and / or back of the cells. Adjacent sets of cells are connected by triangular conductive wires. Specifically, one end of the triangular conductive wire abuts against the composite metal electrode layer of one cell, and the other end abuts against the composite metal electrode layer of another cell. The adjacent cells are connected and connected through the triangular conductive wires, and the multiple cells form a photovoltaic cell array.

[0029] In some embodiments, a passivation layer 4 is provided on the front and / or back of the solar cell. The passivation layer 4 is a single-layer structure or a multi-layer structure formed by stacking multiple layers. The material of the passivation layer 4 is selected from silicon oxide, silicon nitride, and aluminum oxide. An opening 5 is formed on the passivation layer by a continuous or intermittent etching process to expose the poly layer, which includes a p-poly layer 2 and an n-poly layer 3. The opening 5 is used to accommodate the composite metal electrode layer prepared by an electroplating process. The etching process includes laser etching (dry etching) or etch paste etching (wet etching). The specific etching process is a conventional industry practice and will not be described in detail here.

[0030] In some embodiments, the composite metal electrode layer includes a silicon metal alloy layer 6, which is formed by sintering a metal bonding layer and an exposed poly layer through an opening. Specifically, the metal bonding layer is prepared by an electrolytic reduction process, and the metal bonding layer is formed by electroplating at the opening. The metal bonding layer abuts against the n-poly layer 3 or p-poly layer 2 of the battery cell. The material of the metal bonding layer is selected from single metals such as nickel, tungsten, and titanium, or a nickel-tungsten-titanium alloy. The thickness of the metal bonding layer is 0.05 μm to 2 μm.

[0031] The electrolytic reduction process is used to prepare the metal bonding layer. The suitable electroplating current density is 0.5 ASD to 20 ASD. The suitable operating time range is 30 sec to 600 sec. The suitable operating temperature range is 30℃ to 60℃. The thickness of the resulting metal electrode ranges from 0.2 μm to 2 μm. The electroplating solution operating conditions are: nickel sulfamate concentration of 150 g / L to 350 g / L, boric acid concentration of 15 g / L to 35 g / L, and pH value controlled between 2 and 6.

[0032] A silicon alloy layer 6 is formed at the interface between the metal bonding layer and the poly layer by a sintering process. If the material of the metal bonding layer is nickel, the formed silicon alloy layer is a nickel-silicon alloy layer; if the material of the metal bonding layer is tungsten, the formed silicon alloy layer is a tungsten-silicon alloy layer. The preferred material of the metal bonding layer is nickel, forming a nickel-silicon alloy layer.

[0033] The sintering process specifically involves feeding the aforementioned solar cells into a sintering apparatus to prepare a silicon alloy layer. The operating temperature range is 300℃~400℃, and the process can be carried out under atmospheric conditions or with an inert gas atmosphere; the sintering time is 30sec~600sec. After exiting the sintering furnace, the surface oxide layer is removed by applying 1%~5% BOE at room temperature for 30sec~300sec. BOE is short for Buffered Oxide Etchant, which is a wet etching solution used in semiconductor manufacturing, composed of hydrofluoric acid (HF) and ammonium fluoride (NH4F) in a specific ratio.

[0034] In some embodiments, the metal electrode layer further includes a tin electrode layer 7, which is deposited on the surface of the metal-silicon alloy layer by an electroplating process. The thickness of the tin electrode layer is 0.5 μm to 5 μm.

[0035] The tin electrode layer is prepared using an electroplating process, specifically: the suitable electroplating current density is 0.5 ASD to 20 ASD; the suitable operating time range is 30 sec to 600 sec; the suitable operating temperature range is 20℃ to 30℃; and the resulting metal electrode thickness ranges from 0.5 μm to 5 μm. The pH value of the electroplating solution is controlled between 2 and 6, including stannous sulfate with a concentration of 20 g / L to 100 g / L and sulfuric acid with a concentration of 50 g / L to 150 g / L.

[0036] In some embodiments, the composite metal electrode layer is composed of a nickel-silicon alloy layer and a tin electrode layer, with the tin electrode abutting against the triangular conductive wire. Since the tin electrode abutting against the triangular conductive wire is itself composed of metallic tin, it is not necessary to apply solder paste as a connecting layer between the composite metal electrode layer and the triangular conductive wire during the soldering process, thus solving the problem of difficulty in controlling the amount of solder paste adhering during traditional solder paste application.

[0037] Example 1

[0038] The battery cell in this embodiment is a TOPCon battery.

[0039] See appendix Figure 1 As shown, the outermost passivation layer 5 of the TOPCon cell 1 is partially removed to form an opening 5, exposing the n poly layer 3 and the p poly layer 2.

[0040] See appendix Figure 2 As shown, a metal bonding layer is deposited by electroplating and a silicon metal alloy layer 6 is prepared by sintering.

[0041] See appendix Figure 3 As described above, a tin electrode layer 7 is deposited on the surface of the silicon alloy layer 6 by an electroplating process, and the thickness of the tin electrode layer is 2 μm.

[0042] Example 2

[0043] Example 2 is basically the same as Example 1, the main difference being that the thickness of the prepared tin electrode layer is 3 μm.

[0044] Example 3

[0045] Example 3 is basically the same as Example 1, the main difference being that the thickness of the prepared tin electrode layer is 4 μm.

[0046] Example 4

[0047] The battery cells in this embodiment are BC batteries.

[0048] See appendix Figure 4 As shown, the passivation layer 2 on the back of the BC cell 1 is partially removed to form an opening 4, exposing the npoly layer 3 and the ppoly layer 2.

[0049] See appendix Figure 5 As shown, a metal bonding layer is deposited at the opening 5 by electroplating, and a silicon metal alloy layer 6 is prepared by sintering.

[0050] See appendix Figure 6 As described above, a tin electrode layer 7 is deposited on the surface of the silicon alloy layer 6 by an electroplating process, and the thickness of the tin electrode layer is 2 μm.

[0051] Example 5

[0052] Example 5 is basically the same as Example 4, the main difference being that the thickness of the prepared tin electrode layer is 3 μm.

[0053] Example 6

[0054] Example 6 is basically the same as Example 4, the main difference being that the thickness of the prepared tin electrode layer is 4 μm.

[0055] Comparative Example 1

[0056] The main difference between Comparative Example 1 and Example 1 is that the composite metal electrode layer in Example 1 is replaced by conductive silver paste with a thickness of 3 μm, and solder paste is applied between the conductive silver paste and the triangular conductive wire for connection.

[0057] Comparative Example 2

[0058] The main difference between Comparative Example 2 and Example 4 is that the composite metal electrode layer in Example 4 is replaced by conductive silver paste with a thickness of 3 μm, and solder paste is applied between the conductive silver paste and the triangular conductive wire for connection.

[0059] Experimental Examples

[0060] The performance of the solar cells prepared in Examples 1-6 and Comparative Examples 1-2 was tested, and the test data are shown in Table 1.

[0061] Table 1

[0062] Eta Voc FF Rs Example 1 1.04 3.21 1.08 0.9902 Example 2 1.07 3.22 1.11 0.9895 Example 3 1.09 3.20 1.11 0.9884 Comparative Example 1 1 1 1 1

[0063] Table 2

[0064] Eta Voc FF Rs Example 4 1.06 3.41 1.04 0.9912 Example 5 1.09 3.41 1.05 0.9891 Example 6 1.11 3.37 1.05 0.9984 Comparative Example 2 1 1 1 1

[0065] The experimental data in Tables 1 and 2 show that, compared with the traditional method of coating conductive silver paste, the composite metal electrode layer prepared by electroplating improves the photoelectric conversion efficiency (Eta), opening voltage (Voc), and fill factor (FF) of the solar cell, while reducing the series resistance (Rs), resulting in better solar cell performance.

[0066] In the description of this utility model, it should be understood that 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., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0067] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it. They cannot be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the protection scope of this utility model.

Claims

1. A photovoltaic cell pack with a composite metal electrode layer, characterized in that, include: A battery cell, wherein multiple battery cells are provided, and a composite metal electrode layer is provided on the front and / or back of the battery cell, the composite metal electrode layer including a tin electrode layer; A triangular conductive wire, one end of which abuts against the tin electrode layer of one battery cell, and the other end of which abuts against the tin electrode layer of another battery cell, is used to connect two adjacent battery cells.

2. The photovoltaic cell pack with a composite metal electrode layer according to claim 1, characterized in that, The composite metal electrode layer also includes a silicon alloy layer.

3. The photovoltaic cell pack with a composite metal electrode layer according to claim 2, characterized in that, The silicon alloy layer is a nickel-silicon alloy layer.

4. The photovoltaic cell pack with a composite metal electrode layer according to claim 2, characterized in that, The silicon alloy layer is obtained by sintering a metal bonding layer and a poly layer.

5. The photovoltaic cell pack with a composite metal electrode layer according to claim 4, characterized in that, The metal bonding layer abuts against the n-poly layer or p-poly layer of the battery cell. The material of the metal bonding layer is selected from single metals such as nickel, tungsten, and titanium, or nickel alloys, tungsten alloys, and titanium alloys. The thickness of the metal bonding layer is 0.2 μm to 2 μm.

6. The photovoltaic cell pack with a composite metal electrode layer according to claim 5, characterized in that, The material of the metal connecting layer is nickel.

7. The photovoltaic cell pack with a composite metal electrode layer according to claim 2, characterized in that, The tin electrode layer and the silicon metal alloy layer abut against each other, and the tin electrode layer is located on the side of the silicon metal alloy layer away from the solar cell.

8. The photovoltaic cell pack with a composite metal electrode layer according to claim 7, characterized in that, The thickness of the tin electrode layer is 0.5μm to 5μm.

9. The photovoltaic cell pack with a composite metal electrode layer according to claim 1, characterized in that, A passivation layer is provided on the front and / or back of the battery cell, and an opening is formed on the passivation layer by an etching process. The opening is used to accommodate a composite metal electrode layer prepared by an electroplating process.

10. The photovoltaic cell pack with a composite metal electrode layer according to claim 1, characterized in that, The composite metal electrode layer consists of a nickel-silicon alloy layer and a tin electrode layer. The tin electrode layer is deposited on the surface of the nickel-silicon alloy layer by an electroplating process, and the tin electrode abuts against the triangular conductive wire.

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