A battery cell with a stress dispersion structure

Abstract

This utility model discloses a battery cell with a stress-dispersing structure, comprising: a battery cell body; metal grid lines, wherein the metal grid lines are strip-shaped; and a stress-dispersing structure disposed at the ends of the metal grid lines and integrally connected to the metal grid lines, protruding from the metal grid lines in the width direction. This solution increases the stress distribution area by providing a stress-dispersing structure at the ends of the metal grid lines with a width greater than the width of the metal grid lines. This causes the area at stress concentration points to increase along with the area of ​​the stress-dispersing structure, thus reducing the stress per unit area. Therefore, it can prevent the metal grid lines from warping or detaching due to stress concentration at their ends.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic cells, specifically to a cell with a stress dispersion structure. Background Technology

[0002] Electroplated metal grids have become a core metallization technology in the photovoltaic industry for "reducing costs, improving efficiency, and increasing grid density by eliminating silver plating." However, as shown in the attached... Figure 1 As shown, in the prior art, the stress concentration area A1 of a single metal grid line is very small. Therefore, the stress will be concentrated at the endpoints, which will cause the metal grid line to peel off or fall off the solar cell. Utility Model Content

[0003] To overcome the above-mentioned shortcomings, the purpose of this utility model is to provide a battery cell with a stress-dispersing structure. The stress-dispersing structure is set at the end of the original metal grid line to disperse the stress at the end of the metal grid line, improve the bonding force between the metal grid line and the battery cell, and prevent the metal grid line from peeling off or falling off.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is: a battery cell with a stress dispersion structure, comprising:

[0005] The battery cell itself;

[0006] Metal grid lines, wherein the metal grid lines are strip-shaped structures;

[0007] A stress-dispersing structure is disposed at the end of the metal grid line and integrally connected with the metal grid line, and the stress-dispersing structure protrudes from the metal grid line in the width direction of the metal grid line.

[0008] Furthermore, the stress dispersion structure is a strip structure, and the angle between it and the metal grid line ranges from 90° to 175°.

[0009] Furthermore, the stress dispersion structure is a strip structure, with its middle part connected to the end of the metal grid line, forming a "T"-shaped structure with the metal grid line;

[0010] Alternatively, the stress dispersion structure is a "V" shaped structure, connected to the end of the metal grid line, forming a "Y" shaped structure with the metal grid line.

[0011] Furthermore, the included angle formed by the "V"-shaped stress dispersion structure is θ, and the range of θ is 5° to 175°.

[0012] Furthermore, the stress dispersion structure includes reinforcement points, of which 2 to 200 are provided, symmetrically distributed around the metal grid line. The width of the metal grid line is W, and the distance between two adjacent reinforcement points is W2, satisfying the following relationship: 0.2W≤W2≤5W.

[0013] Furthermore, the reinforcement points are linearly distributed at the ends of the metal grid line. The distance from the nearest reinforcement point to the side of the metal grid line is W1, and the distance from the nearest reinforcement point to the end of the metal grid line is H, satisfying the following relationship: 0.2W≤W1≤5W, 0≤H≤3W.

[0014] Furthermore, the reinforcement points are distributed in a V-shape at the ends of the metal grid line, and the distance from the nearest reinforcement point to the metal grid line is W3, satisfying the following relationship: 0.2W≤W3≤5W.

[0015] Furthermore, the reinforcement point is a reinforced nickel-silicon alloy layer located at the end of the metal grid line.

[0016] Furthermore, the stress dispersion structure also includes a reinforced copper metal electrode located on the surface of the reinforced nickel-silicon alloy layer, which is deposited on the surface of the reinforced nickel-silicon alloy layer by an electroplating process.

[0017] Furthermore, the stress dispersion structure also includes a reinforcing tin metal protective layer located on the surface of the reinforced copper metal electrode, which is deposited on the surface of the reinforced copper metal electrode by an electroplating 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 of a metal grid line in the prior art;

[0021] Figure 2 A schematic diagram of a solar cell with a stress-dispersion structure;

[0022] Figure 3 This is a schematic diagram of a stress dispersion structure according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the stress dispersion structure according to another embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the stress dispersion structure of another embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram showing the location of the reinforcement points according to an embodiment of the present invention;

[0026] Figure 7 This is a top view of the opening position according to an embodiment of the present invention;

[0027] Figure 8 This is a front view of the opening position according to an embodiment of the present invention.

[0028] Figure 9 This is a top view of the reinforcement point according to an embodiment of the present invention;

[0029] Figure 10 This is a front view of the reinforcement point according to an embodiment of the present invention;

[0030] Figure 11 This is a top view of a reinforced copper metal electrode according to an embodiment of the present invention;

[0031] Figure 12 This is a front view of a reinforced copper metal electrode according to an embodiment of the present invention;

[0032] Figure 13 This is a top view of a reinforced tin metal protective layer according to an embodiment of the present invention;

[0033] Figure 14 This is a front view of a reinforced tin metal protective layer according to an embodiment of the present invention.

[0034] In the figure: 1. Cell body; 2. Metal grid lines; 21. Nickel-silicon alloy layer; 22. Metal electrode; 23. Tin metal protective layer; 3. Passivation layer; 31. Metal grid line opening; 32. Reinforcement opening; 4. Stress dispersion structure; 41. Reinforcement point; 42. Reinforced copper metal electrode; 43. Reinforced tin metal protective layer. Detailed Implementation

[0035] 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.

[0036] See appendix Figure 2 As shown, a battery cell with a stress-dispersing structure in this embodiment includes a battery cell body 1. Metal grid lines 2 are provided on the front and / or back of the battery cell body 1. The metal grid lines 2 are strip-shaped structures used to collect and transport charge carriers. The metal grid lines 2 can be provided on both the front and back of the battery cell body 1, such as in a TOPCon battery. Alternatively, the metal grid lines 2 can be provided only on the back of the battery cell, such as in a BC battery.

[0037] The solar cell also includes a stress-dispersing structure 4, which is disposed at the end of the metal grid line 2 and integrally connected with the metal grid line 2. The stress-dispersing structure 4 protrudes from the metal grid line 2 in the width direction of the metal grid line 2. (See attached diagram) Figure 1 As shown, in the prior art, the area A1 at the stress concentration point of a single metal grid line 2 is very small. Therefore, the stress will be concentrated almost at the endpoints, causing grid detachment. This solution increases the stress distribution area by setting a stress dispersion structure 4 at the end of the metal grid line 2 with a width greater than the width of the metal grid line 2. This increases the area at the stress concentration point as the area of ​​the stress dispersion structure 4 increases, thus reducing the stress per unit area. Therefore, it avoids the occurrence of metal grid line warping or detachment due to stress concentration at the endpoints of the original metal grid line.

[0038] In some embodiments, the stress dispersion structure 4 is a strip structure, and the angle between it and the metal grid line 2 ranges from 90° to 175°.

[0039] In some embodiments, see Appendix Figure 3 As shown, the stress dispersion structure 4 is a strip structure, with its middle part connected to the end of the metal grid line 2, forming a "T"-shaped structure with the metal grid line 2.

[0040] In some embodiments, see Appendix Figure 4 As shown, the stress dispersion structure 4 is a "V" shaped structure, and the included angle formed by the "V" shaped stress dispersion structure 4 is θ, with θ ranging from 5° to 175°. The "V" shaped stress dispersion structure 4 is connected to the end of the metal grid line 2, forming a "Y" shaped structure with the metal grid line 2.

[0041] In some embodiments, see Appendix Figure 5 As shown, the stress dispersion structure 4 is a polygonal structure, which is connected to the end of the metal grid line 2. The polygon can be a triangle, a quadrilateral, a pentagon, etc.

[0042] In some embodiments, see Appendix Figure 3-5As shown, the stress dispersion structure 4 includes reinforcement points 41, of which 2 to 200 are provided, symmetrically distributed around the metal grid line 2. The reinforcement points 41 are reinforcement nickel-silicon alloy layers located at the ends of the metal grid line 2. A laser-drilled opening is made in the passivation layer 3 of the solar cell, located at the end of the metal grid line. A nickel bonding layer is deposited at the opening, and the nickel bonding layer and the ply layer are calcined to form the reinforcement nickel-silicon alloy layer.

[0043] In some embodiments, see Appendix Figure 3 and attached Figure 4 As shown, the width of the metal grid line 2 is W, and the distance between two adjacent reinforcement points 41 is W2, satisfying the following relationship: 0.2W ≤ W2 ≤ 5W. In this scheme, the distance between reinforcement points 41 is the distance between the center points of reinforcement points 41. When the distance between reinforcement points 41 is relatively small, the laser openings are relatively dense, increasing the difficulty and cost of laser opening. When the distance between reinforcement points 41 is large, when preparing the reinforcement copper metal electrode 42 by electroplating on the reinforcement points 41 later, the reinforcement copper metal electrode 42 on two adjacent reinforcement points 41 may not be connected together, failing to form a continuous straight line, resulting in the inability to disperse the stress at the end of the metal grid line. Therefore, in this scheme, the distance between two adjacent reinforcement points 41 is most suitable between 0.2W and 5W.

[0044] In some embodiments, see Appendix Figure 6 As shown, reinforcement points 41 are linearly distributed at the ends of the metal grid line 2. The distance from the nearest reinforcement point 41 to the side of the metal grid line 2 is W1. The distance W1 is the vertical distance from the reinforcement point 41 to the side of the metal grid line 2 or the extension line of the side of the metal grid line 2. W1 satisfies the following relationship: W≤W1≤5W. The distance from the nearest reinforcement point 41 to the end of the metal grid line 2 is H. The distance H is the vertical distance from the reinforcement point 41 to the top of the metal grid line 2 or the extension line of the top of the metal grid line 2. H satisfies the following relationship: 0≤H≤3W.

[0045] In some embodiments, see Appendix Figure 4 The reinforcement points 41 are distributed in a V-shape at the end of the metal grid line 2. The distance from the nearest reinforcement point 41 to the metal grid line 2 is W3, which satisfies the following relationship: 0.2W≤W3≤5W.

[0046] In some embodiments, the stress dispersion structure 4 further includes a reinforcing copper metal electrode 42 located on the surface of the reinforcement point 41 (reinforcing nickel-silicon alloy layer), which is deposited on the surface of the reinforcement point 41 by an electroplating process. Since the reinforcing copper metal electrode 42 formed during the electroplating process can cover the surface of the reinforcement point 41, its surface area is larger than the surface area of ​​the reinforcement point 41. The reinforcing copper metal electrodes 42 above two adjacent reinforcement points 41 can be connected together to form a linear structure, and can be connected with the metal electrode of the metal grid line 2 to disperse the stress of the metal grid line 2.

[0047] In some embodiments, the stress dispersion structure 4 further includes a reinforced tin metal protective layer 43 located on the surface of the reinforced copper metal electrode 42, which is deposited on the surface of the reinforced copper metal electrode 42 by an electroplating process.

[0048] In some embodiments, the stress dispersion structure 4 and the metal grid line 2 are prepared simultaneously, without the need for additional preparation steps.

[0049] The specific preparation steps are as follows:

[0050] Step 1, see appendix Figure 7 and attached Figure 8 An opening is formed on the passivation layer 3 by laser process. The opening is a dot structure and includes a metal grid opening 31 for preparing the metal grid line and a reinforcement opening 32 located at the end of the metal grid line for preparing the stress dispersion structure 4.

[0051] Step 2, see appendix Figure 9 and attached Figure 10 TOPCon solar cells with exposed n-poly and p-poly layers at the openings are fed into a PVD deposition apparatus to prepare nickel metal layers in the exposed n-poly and p-poly electrode regions. The thickness of the deposited nickel metal layer is 5 nm to 50 nm. Specific operating conditions are: operating power 1–10 kW; operating time 30–600 seconds; operating temperature 200–350 °C. The nickel metal layer is deposited within the metal grid opening 31 and the reinforcement opening 32.

[0052] Step 3: The above-mentioned battery cells are sent to a sintering apparatus to prepare the nickel-silicon alloy layer. The operating temperature range is 200℃~400℃, which can be carried out under atmospheric conditions or with an inert gas; the sintering time is 30sec~600sec; or the sintering can be carried out in a vacuum chamber at a temperature range of 200℃~400℃ and a sintering time of 10sec~300sec. Then, the surface oxide layer is removed by sintering with 1%~5% BOE at room temperature for 30sec~300sec.

[0053] The nickel metal layer and poly layer located within the metal grid opening 31 are sintered to form the nickel-silicon alloy layer 21 of the metal grid 2, and the nickel metal layer and poly layer located within the reinforcement opening 32 are sintered to form the reinforced nickel-silicon alloy layer of the stress dispersion structure 4. The nickel-silicon alloy layer 21 and the reinforced nickel-silicon alloy layer (reinforcement point 41) are formed simultaneously during the sintering process.

[0054] Step 4, see appendix Figure 11 and attached Figure 12 Metal electrodes 22 were prepared using an electrolytic reduction process. The suitable electroplating current density was 5 ASD to 50 ASD. The operating time ranged from 120 seconds to 3600 seconds. The operating temperature ranged from 20℃ to 40℃ for the metal electrode electroplating process. The electroplating solution operating conditions were as follows: copper sulfate concentration: typically controlled at 100 g / L to 250 g / L; sulfuric acid concentration: ranged from 55 g / L to 75 g / L; hydrochloric acid concentration: ranged from 55 g / L to 125 g / L.

[0055] During the fabrication of the copper metal electrode 22 of the metal grid line 2, the reinforced copper metal electrode 42 with stress dispersion structure 4 is simultaneously formed on the surface of the reinforced nickel-silicon alloy layer.

[0056] Step 4, see appendix Figure 13 and attached Figure 14 A tin metal protective layer 23 is prepared using an electrolytic reduction process. The suitable electroplating current density is 2 ASD to 20 ASD. The suitable operating time range is 20 seconds to 360 seconds. The suitable operating temperature range is 20℃ to 40℃ for the metal electrode electroplating process. The electroplating solution operating conditions are Sn... 2+ (Divalent tin) concentration range of 10 g / L to 60 g / L; methanesulfonic acid concentration range of 35 mL / L to 60 mL / L, for electrodeposition of 0.1 μm to 3 μm.

[0057] During the preparation of the tin metal protective layer 23 of the metal grid line 2, the reinforced tin metal protective layer 43 of the stress dispersion structure 4 is simultaneously formed on the surface of the reinforced copper metal electrode.

[0058] This solution utilizes T-shaped or Y-shaped reinforcement points at the ends of the original metal grid lines. This is an effective and easily implemented process that does not significantly increase processing time. The T-shaped or Y-shaped structures are used because the reinforcement points at the ends of the metal grid lines disperse stress along the increased area created by the reinforcement points after metal deposition. Adding these reinforcement points does not significantly increase processing time or cause damage to the solar cells. Furthermore, this process can be implemented on solar cells of any structure.

[0059] 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.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] 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 battery sheet having a stress dispersion structure, characterized by, include: Battery cell body (1); Metal grid line (2), wherein the metal grid line (2) is a strip structure; The stress dispersion structure (4) is disposed at the end of the metal grid line (2) and integrally connected with the metal grid line (2). The stress dispersion structure protrudes from the metal grid line (2) in the width direction of the metal grid line (2).

2. The battery sheet having a stress dispersion structure according to claim 1, wherein, The stress dispersion structure (4) is a strip structure, and the angle between it and the metal grid line (2) is in the range of 90 to 175°.

3. The battery cell with a stress dispersion structure according to claim 1, characterized in that, The stress dispersion structure (4) is a strip structure, the middle part of which is connected to the end of the metal grid line (2), and together with the metal grid line (2) forms a "T" shaped structure; Alternatively, the stress dispersion structure (4) is a "V" shaped structure, connected to the end of the metal grid line (2), and forms a "Y" shaped structure with the metal grid line (2).

4. The battery sheet having a stress dispersion structure according to claim 3, characterized by, The included angle formed by the "V"-shaped stress dispersion structure (4) is θ, and the range of θ is 5° to 175°.

5. The battery sheet having a stress dispersion structure according to claim 1, wherein, The stress dispersion structure (4) includes reinforcement points (41), and there are 2 to 200 reinforcement points (41) symmetrically distributed around the metal grid line (2). The width of the metal grid line (2) is W, and the distance between two adjacent reinforcement points (41) is W2, satisfying the following relationship: 0.2W≤W2≤5W.

6. The battery sheet having a stress dispersion structure according to claim 5, wherein, The reinforcement points (41) are linearly distributed at the ends of the metal grid line (2). The distance from the nearest reinforcement point (41) to the side of the metal grid line (2) is W1, and the distance from the nearest reinforcement point (41) to the end of the metal grid line (2) is H, satisfying the following relationship: 0.2W≤W1≤5W, 0≤H≤3W.

7. The battery cell with a stress dispersion structure according to claim 5, characterized in that, The reinforcement points (41) are distributed in a V-shape at the end of the metal grid line (2). The distance from the reinforcement point (41) closest to the metal grid line (2) to the metal grid line (2) is W3, which satisfies the following relationship: 0.2W≤W3≤5W.

8. The battery sheet having a stress dispersion structure according to claim 5, wherein, The reinforcement point (41) is a reinforced nickel-silicon alloy layer located at the end of the metal grid line (2).

9. The battery sheet having a stress dispersion structure according to claim 8, characterized by, The stress dispersion structure (4) also includes a reinforced copper metal electrode (42) located on the surface of the reinforced nickel-silicon alloy layer, which is deposited on the surface of the reinforced nickel-silicon alloy layer by an electroplating process.

10. The battery sheet having a stress dispersion structure according to claim 9, wherein, The stress dispersion structure (4) also includes a reinforced tin metal protective layer (43) located on the surface of the reinforced copper metal electrode (42), which is deposited on the surface of the reinforced copper metal electrode (42) by an electroplating process.

Images