Conformal assembly and battery weld assembly

Abstract

The application relates to a bonding assembly and a battery welding assembly, the bonding assembly is used for welding a battery piece and a welding strip, and the bonding assembly comprises a bonding piece, the side, away from the battery piece, of the bonding piece is outwardly convex to form a convex part, the outer surface of the convex part is arranged in a curved surface mode, and the convex part can be used for gathering laser spots so that the diameter of the gathered laser spots is smaller than the width of the welding strip. When laser irradiation is performed, the convex part can change the path of the laser, thereby gathering the laser spots, so that the laser spots become small, the diameter of the gathered laser spots is smaller than the width of the welding strip, and the setting of the convex part can avoid that the laser directly irradiates on the peripheral insulating glue of the welding strip, and can avoid that the insulating glue is invalid and a short circuit problem occurs.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a bonding module and a battery welding module. Background Technology

[0002] Back-contact batteries have no grid lines on the front; the positive and negative electrodes are arranged alternately on the back. During the fabrication of back-contact battery modules, insulating adhesive is applied to the positions corresponding to the solder ribbons connecting the positive and negative electrodes on the negative electrode grid lines of the battery cells. Similarly, insulating adhesive is also applied to the positions corresponding to the solder ribbons connecting the negative and positive electrodes on the positive electrode grid lines. Currently, conventional back-contact battery modules use infrared welding. This method uses infrared heating tubes to first weld the individual battery cells into battery strings using solder ribbons, then transports the battery strings onto the module's backplate, and finally solders multiple battery strings together using a soldering iron. This method requires a second handling of the battery strings on the backplate after welding the cells, which can easily cause microcracks at the beginning and end of the battery strings, affecting battery quality.

[0003] Laser welding is currently an alternative to infrared welding. The main steps of laser welding include: printing solder paste on the solder joints of the solar cells, applying insulating adhesive where needed, placing the solder ribbon in the direction of the main busbar, laying an organic silicone film on top of the entire module, and finally irradiating the solder joint area with a laser spot for localized laser welding. However, this method has the following problems: during laser welding, the minimum diameter of the laser spot irradiating the solder ribbon after collimation is 2mm, while the width of a typical flat solder ribbon is no more than 1.5mm. This can easily lead to some laser light directly irradiating the insulating adhesive around the solder ribbon, causing the insulating adhesive to fail and resulting in a short circuit. Utility Model Content

[0004] Based on this, a bonding component and a battery welding component are provided. During the laser welding process of the bonding component, the laser path is changed and the laser spot is focused, thereby making the laser spot smaller. The diameter of the focused laser spot is smaller than the width of the welding strip, which avoids some laser directly irradiating the insulating adhesive on the outer edge of the welding strip, thus avoiding short circuit problems caused by insulation adhesive failure.

[0005] To this end, in a first aspect, embodiments of this application provide a bonding assembly for welding a battery cell to a solder strip, including a bonding member, wherein the bonding member protrudes outward on the side opposite to the battery cell to form a protrusion, the outer surface of the protrusion being curved, and the protrusion being used to focus a laser spot so that the diameter of the focused laser spot is smaller than the width of the solder strip.

[0006] In one embodiment, the protrusion is a spherical cap, the height of the protrusion is H, and the diameter of the bottom surface of the protrusion is D, where H:D = 1:2-4.

[0007] In one embodiment, a plurality of protrusions are provided, and the plurality of protrusions are arranged at intervals along the length and width directions of the bonding member.

[0008] In one embodiment, the material of the bonding element is any one of silicone film, EVA film, PVB film, and POE film.

[0009] In one embodiment, the side of the bonding component facing away from the protrusion is provided with a protective groove, the protective groove being used to cover the solder ribbon and solder paste, and the protrusion being provided corresponding to the protective groove.

[0010] In one embodiment, the cross-section of the protective groove is either rectangular or trapezoidal.

[0011] In one embodiment, a transparent adhesive layer is provided inside the protective groove.

[0012] In one embodiment, the transparent adhesive layer is coated on the inner wall of the protective groove.

[0013] In one embodiment, the transparent adhesive layer is any one of acrylic adhesive, epoxy resin adhesive, and silicone adhesive.

[0014] Secondly, embodiments of this application provide a battery welding assembly, including battery cells, welding strips, and bonding components as described in any of the preceding claims.

[0015] According to the embodiments of this application, the bonding assembly and battery welding assembly are used to weld battery cells to welding ribbons. The bonding assembly includes a bonding member, which protrudes outward from the side opposite to the battery cell to form a protrusion. The outer surface of the protrusion is curved. The protrusion can be used to focus the laser spot so that the diameter of the focused laser spot is smaller than the width of the welding ribbon. When the laser irradiates, the protrusion can change the laser path, thereby focusing the laser spot and making the laser spot smaller. The diameter of the focused laser spot is smaller than the width of the welding ribbon. The protrusion can prevent the laser from directly irradiating the insulating adhesive around the welding ribbon, thus avoiding short circuit problems caused by adhesive failure. Attached Figure Description

[0016] Figure 1 This illustration shows a structural schematic diagram of a battery welding assembly provided in an embodiment of this application.

[0017] Figure 2 This illustration shows a structural schematic diagram of a battery cell provided in an embodiment of this application;

[0018] Figure 3 This illustration shows a structural diagram of a battery cell and solder strip provided in an embodiment of this application;

[0019] Figure 4 This illustration shows a structural diagram of a battery cell and solder paste provided in an embodiment of this application;

[0020] Figure 5 This diagram illustrates the structure of an adhesive component according to an embodiment of this application.

[0021] Figure 6 This diagram shows a partial schematic of a battery welding assembly provided in an embodiment of this application.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Battery cell; 11. Positive main grid line; 111. Positive fine grid line; 112. Positive solder joint; 12. Negative main grid line; 121. Negative fine grid line; 122. Negative solder joint; 2. Solder ribbon; 3. Adhesive piece; 31. Protrusion; 32. Protective groove; 33. Transparent adhesive layer; 4. Insulating adhesive; 5. Solder paste; 6. Laser spot. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0025] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. Therefore, the drawings only show the components related to this utility model and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0026] The structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0027] The orientations or positional relationships indicated by terms such as "upper," "lower," "left," "right," "middle," "longitudinal," "transverse," "horizontal," "inner," "outer," "radial," and "circumferential" used in this specification are based on the orientations or positional relationships shown in the accompanying drawings and are only for the purpose of simplifying the description. They do not 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 limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] Laser welding achieves main busbar laser plate welding. Solder paste 5 is printed on the solder joints of the solar cell 1, and insulating adhesive is applied where necessary. The solder ribbon 2 is placed in the direction of the main busbar, and then an organic silicone film is laid on top of the entire module. Finally, the laser spot 6 irradiates the solder joint area for local laser welding. However, this method has the following problems: During the laser welding process, after the laser spot 6 is adjusted by the collimator, the minimum spot diameter irradiating the solder ribbon 2 is 2mm, while the width of the commonly used flat solder ribbon 2 is no more than 1.5mm. This can easily cause some laser to directly irradiate the insulating adhesive 4 around the solder ribbon, leading to the failure of the insulating adhesive 4 and a short circuit problem.

[0029] To solve the above problems, refer to Figures 1-6 , Figure 1 This diagram illustrates the structure of a battery welding assembly according to an embodiment of this application. Figure 2 This illustration shows a structural schematic diagram of a battery cell provided in an embodiment of this application. Figure 3 This illustration shows a structural diagram of a battery cell and solder strip according to an embodiment of this application. Figure 4 This diagram illustrates the structure of a battery cell and solder paste according to an embodiment of this application. Figure 5 This diagram illustrates the structure of an adhesive component according to an embodiment of this application. Figure 6 This diagram shows a partial schematic of a battery welding assembly provided in an embodiment of this application.

[0030] This application provides a bonding assembly for welding a battery cell 1 to a solder strip 2. The bonding assembly includes a bonding member 3, which protrudes outward on the side opposite to the battery cell 1 to form a protrusion 31. The outer surface of the protrusion 31 is curved. The protrusion 31 can be used to focus a laser spot 6 so that the diameter of the focused laser spot 6 is smaller than the width of the solder strip 2.

[0031] Reference Figures 2-4It is important to understand that the battery cell 1 includes a positive main grid line 11 and a negative main grid line 12 with opposite polarities. The positive main grid line 11 extends into a positive fine grid line 111, and the negative main grid line 12 extends into a negative fine grid line 121. The positive fine grid line 111 and the negative fine grid line 121 are arranged in parallel. The positive fine grid line 111 and the negative main grid line 12 do not intersect, and the negative fine grid line 121 and the positive main grid line 11 do not intersect. The positive main grid line 11 and the negative main grid line 12 are mainly used to collect the current generated by the battery cell and transmit it to the external circuit. The positive fine grid line 111 and the negative fine grid line 121 are distributed on the surface of the battery cell and are used to collect the current generated in various areas of the battery cell 1 and transmit it to the positive main grid line 11 and the negative main grid line 12. They are usually thin and densely distributed. Their function is to reduce the series resistance of the battery cell 1 and improve the output performance of the battery.

[0032] Positive electrode solder joints 112 are distributed on the positive electrode main grid line 11 of the battery cell 1, and negative electrode solder joints 122 are distributed on the negative electrode main grid line 12. After the insulating adhesive and solder paste 5 are printed and dried respectively, solder ribbon 2 is placed on the battery cell 1. The solder ribbon 2 corresponds to the positive electrode solder joint 112 or the negative electrode solder joint 122. The laser spot 6 hits the solder ribbon 2 corresponding to the positive electrode solder joint 112 or the negative electrode solder joint 122. The solder paste 5 melts to complete the welding between the solder ribbon 2 and the positive electrode solder joint 112 or the negative electrode solder joint 122, so as to complete the welding between the battery cell 1 and the solder ribbon 2.

[0033] Reference Figure 1 , Figure 4 and Figure 5 The bonding assembly includes a bonding member 3, which is plate-shaped and rectangular, used to connect the battery cell 1 to the solder ribbon 2. A protrusion 31 is integrally formed on the side of the bonding member 3 opposite to the battery cell 1, corresponding to the positive electrode solder joint 112 or the negative electrode solder joint 122. The surface of the protrusion 31 is curved. When irradiated by a laser, the protrusion 31 can change the laser path, thereby focusing the laser spot 6, making the laser spot 6 smaller. The diameter of the focused laser spot 6 is smaller than the width of the solder ribbon 2. In one example, the diameter of the laser spot 6 is 0.5mm-5mm. The protrusion 31 prevents the laser from directly irradiating the insulating adhesive 4 surrounding the solder ribbon 2, avoiding short circuit problems caused by the failure of the insulating adhesive 4.

[0034] During welding, the battery cell 1 and the welding ribbon 2 are arranged, and then the bonding component 3 is placed on top of the welding ribbon 2 so that the protrusion 31 of the bonding component 3 corresponds to the positive electrode welding point 112 or the negative electrode welding point 122. Then, vacuum fixation is performed. After fixation is completed, the laser is directed towards the protrusion 31 to weld the positive electrode welding point 112 or the negative electrode welding point 122 of the battery cell 1 to the welding ribbon 2.

[0035] Reference Figure 6In some optional embodiments, protrusion 31 is a spherical cap, with a height of H and a bottom diameter of D, where H:D = 1:2-4. A spherical cap is a portion of a sphere cut off by a plane. After the diameter perpendicular to the cross-section is cut off, the remaining length of the spherical cap is called its height, and the cross-section is called its bottom. The height of protrusion 31 is the height of the spherical cap, and the bottom of protrusion 31 is the bottom of the spherical cap. H:D can be 1:2, 1:3, or 1:4; this application does not impose any limitations. When H:D equals 1:3, the welding effect between the battery cell 1 and the solder ribbon 2 is optimal, without affecting the insulating adhesive 4.

[0036] Reference Figure 5 In some optional embodiments, multiple protrusions 31 are provided, and the multiple protrusions 31 are arranged at intervals along the length and width directions of the bonding member 3. The number of protrusions 31 is equal to the total number of positive electrode solder joints 112 and negative electrode solder joints 122. Each protrusion 31 corresponds to a solder joint, which can be either a positive electrode solder joint 112 or a negative electrode solder joint 122. The arrangement of multiple protrusions 31 ensures that the laser spot 6 at the solder joint of the battery cell 1 is smaller than the width of the solder strip 2.

[0037] In some optional embodiments, the material of the bonding element 3 is any one of silicone film, EVA film, PVB film, and POE film.

[0038] Silicone film has high temperature resistance: it has excellent high temperature resistance and can maintain stable physical and chemical properties at high temperatures. It can be used for a long time in environments above 200°C, and can even withstand higher temperatures for a short time. This makes it suitable for some high-temperature applications. Silicone film also has chemical stability: it has good resistance to most chemicals and is not easily corroded by acids, alkalis, organic solvents, etc., which improves its service life.

[0039] EVA film (ethylene-vinyl acetate copolymer film) has good transparency, which allows light transmittance to reach a high level, enabling more light to pass through to the solar cell 1 and improving the photoelectric conversion efficiency of the cell; it also has anti-aging properties: it has good anti-aging properties, is not prone to embrittlement or cracking, and extends its service life.

[0040] PVB film (polyvinyl butyral film) has excellent optical properties and can maintain the transparency and clarity of glass.

[0041] POE film (polyolefin elastomer film) has excellent optical properties: it has high light transmittance, which allows solar cells to better receive sunlight and improve photoelectric conversion efficiency. At the same time, its low haze allows light to be evenly scattered within the film, reducing shading on the surface of the cell and further improving cell performance. It also has excellent weather resistance: it has strong resistance to ultraviolet rays, heat, oxygen and moisture, and is not prone to aging, yellowing or embrittlement.

[0042] Reference Figure 1 and Figure 6 In some optional embodiments, a protective groove 32 is provided on the side of the bonding component 3 facing away from the protrusion 31. The protective groove 32 is used to cover the solder ribbon 2 and solder paste 5, and the protrusion 31 is correspondingly provided with the protective groove 32. The protective groove 32 extends along the width direction of the bonding component 3. The protective groove 32 can cover the solder ribbon 2 and solder paste 5, thereby improving the tightness between the bonding component 3 and the solder ribbon 2 and avoiding misalignment. At the same time, it can also prevent the bonding component 3 from squeezing the solder ribbon 2, causing solder dross to splatter everywhere. The protective groove 32 can concentrate the solder dross in the protective groove 32 and prevent it from escaping. It can effectively prevent solder dross from splattering onto the battery surface during laser welding and solve the problem of battery short circuit caused by solder dross splattering.

[0043] In some optional embodiments, the cross-section of the protective groove 32 can be either rectangular or trapezoidal. The cross-section of the protective groove 32 can be either rectangular or trapezoidal, and when the cross-section of the protective groove 32 is trapezoidal, it is preferable that the upper base is smaller than the lower base.

[0044] In some optional embodiments, a transparent adhesive layer 33 is provided in the protective groove 32. The transparent adhesive layer 33 can be provided on the upper bottom surface of the protective groove 32, or on one or both side walls of the protective groove 32. This application does not impose any restrictions. The transparent adhesive layer 33 can adhere the splashed solder dross, so as to facilitate the removal of solder dross later. At the same time, the transparent adhesive layer 33 does not affect the laser path and does not affect the welding of the battery cell 1 and the solder ribbon 2.

[0045] In some optional embodiments, the transparent adhesive layer 33 is coated on the inner wall of the protective tank 32, that is, the transparent adhesive layer 33 is coated on the top surface and two side walls of the protective tank 32 to increase the area of ​​the transparent adhesive layer 33 so that more solder dross is adhered.

[0046] In some optional embodiments, the transparent adhesive layer 33 is any one of acrylic adhesive, epoxy resin adhesive, and silicone adhesive. Acrylic adhesives have fast curing speed, high bonding strength, high transparency, and good weather resistance. Epoxy resin adhesives have high bonding strength: the epoxy groups in their molecular structure can react with a variety of substances to form strong chemical bonds, resulting in excellent adhesion to various materials. Silicone adhesives are resistant to both high and low temperatures: they maintain stable performance over a wide temperature range and also have good weather resistance.

[0047] Reference Figures 1-6 This application also includes a battery welding assembly, comprising a battery cell 1, a welding ribbon 2, and a bonding assembly as described in any of the above. The bonding assembly is used to weld the battery cell 1 to the welding ribbon 2. The bonding assembly includes a bonding member 3, which protrudes outward from the side opposite to the battery cell 1 to form a protrusion 31. The outer surface of the protrusion 31 is curved. The protrusion 31 can be used to focus a laser spot 6 so that the diameter of the focused laser spot 6 is smaller than the width of the welding ribbon 2.

[0048] When irradiated by laser, the protrusion 31 can change the laser path, thereby focusing the laser spot 6 and making the laser spot 6 smaller. The diameter of the focused laser spot 6 is smaller than the width of the solder ribbon 2. The protrusion 31 can prevent the laser from directly irradiating the insulating adhesive 4 on the outer periphery of the solder ribbon 2, thus avoiding short circuit problems caused by the failure of the insulating adhesive 4.

[0049] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0050] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A bonding assembly for welding a battery cell (1) to a solder strip (2), characterized in that, The assembly includes a bonding component (3), which protrudes outward on the side opposite to the battery cell (1) to form a protrusion (31). The outer surface of the protrusion (31) is curved. The protrusion (31) can be used to focus the laser spot (6) so that the diameter of the focused laser spot (6) is smaller than the width of the solder strip (2).

2. The bonding component according to claim 1, characterized in that, The protrusion (31) is a spherical cap, the height of the protrusion (31) is H, the bottom diameter of the protrusion (31) is D, and H:D = 1:2-4.

3. The bonding component according to claim 1, characterized in that, The protrusions (31) are provided in multiple ways, and the multiple protrusions (31) are arranged at intervals along the length and width directions of the bonding member (3).

4. The bonding component according to claim 1, characterized in that, The material of the bonding component (3) is any one of silicone film, EVA film, PVB film, and POE film.

5. The bonding component according to claim 1, characterized in that, The bonding component (3) has a protective groove (32) on the side facing away from the protrusion (31). The protective groove (32) is used to cover the solder strip (2) and solder paste (5). The protrusion (31) is provided in correspondence with the protective groove (32).

6. The bonding component according to claim 5, characterized in that, The cross-section of the protective groove (32) can be either rectangular or trapezoidal.

7. The bonding component according to claim 5, characterized in that, A transparent adhesive layer (33) is provided inside the protective groove (32).

8. The bonding component according to claim 7, characterized in that, The transparent adhesive layer (33) is coated on the inner wall of the protective groove (32).

9. The bonding component according to claim 7, characterized in that, The transparent adhesive layer (33) can be any one of acrylic resin, epoxy resin, and silicone.

10. A battery welding assembly, characterized in that, It includes a battery cell (1), a solder strip (2), and a bonding assembly as described in any one of claims 1-9.

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