Cable resistance welding module

Abstract

The invention discloses a cable resistance welding module which comprises a metal plate, a cable resistance welding spot, a tin storage groove, a chip welding area, a bus bar through groove and a plastic package body. The metal plate is arranged in the length direction, and cable resistance welding spots are arranged at the two ends of the metal plate. Two rectangular tin storage grooves are symmetrically arranged on the inner side of the cable welding spot, and a chip welding area is formed between the tin storage grooves. A through bus bar through groove is formed in the position, corresponding to the tin storage groove, of the metal plate and used for allowing a bus bar to penetrate through and completing welding together with molten tin in the tin storage groove. The tin storage tank is used for storing tin needed by chip welding and bus bar welding and providing controlled welding flux for a chip welding area in the heating process. The zoned structure between the cable welding spot and the chip welding area enables transient heat of resistance welding not to directly act on the chip welding spot, and the welding reliability is improved. The above structure is finally integrally packaged by a plastic package body, and can be used for bypass diode connection in a photovoltaic module.

Description

A cable resistance welding module Technical Field

[0001] This invention relates to the field of photovoltaic module packaging technology, specifically a cable resistance welding module. Background Technology

[0002] Bypass diodes are commonly found in photovoltaic (PV) modules to provide a bypass path when the module is partially shaded, hotspots occur, or current is discontinuous, thus preventing thermal failure of some cells due to reverse bias. Bypass diodes are typically connected to metal conductive sheets, busbars, and external cables via soldering, and the reliability of this soldering directly affects the overall operational stability and lifespan of the PV module.

[0003] Existing bypass diode soldering structures mainly fall into two categories: one is manual soldering or reflow soldering, where the chip is soldered to the center of a metal plate, and the busbar is connected using solder paste or solder ribbon; the other is riveting or mechanical crimping, where the cable or busbar is fixed to the outside of the metal plate. However, traditional soldering structures generally have the following problems: First, the heating areas of the chip solder joint, busbar solder joint, and cable solder joint are close to each other, making thermal coupling easy to occur during the soldering process. This causes the chip soldering area to be affected by the transient high temperature generated by the cable or busbar soldering, resulting in thermal shock or solder layer voids. Second, in traditional structures, solder often relies on manual coating or localized application, making solder distribution difficult to control. This can lead to insufficient solder, uneven solder diffusion, and cold solder joints, affecting the chip solder joint resistance and long-term stability. Third, the busbar is usually connected to the metal plate by direct soldering or crimping. If the soldering position lacks a stable source of solder or a current-carrying structure, insufficient solder wetting can easily result in a small contact area and high resistance at the solder joint.

[0004] Furthermore, in existing structures, cable solder joints are typically located close to the chip soldering area. The instantaneous heat generated during resistance welding or high-temperature welding is rapidly conducted to the bottom of the chip. Especially when using high-current resistance welding, the chip solder layer is prone to localized overheating, uneven solder melting, and excessive welding stress, affecting the reliability of the bypass diode. For structures employing dual-chip series connection, since the soldering surfaces of both chips need to maintain solder layer consistency, existing single-slot or non-conductive solder storage structures struggle to ensure that both chips receive equal amounts of solder during reflow. This results in inconsistent solder joint thickness and uneven current distribution, potentially causing premature aging or failure of one chip in severe cases. Therefore, designing a cable resistance welding module is essential. Summary of the Invention

[0005] The purpose of this invention is to provide a cable resistance welding module to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a cable resistance welding module, comprising a metal plate, cable resistance welding joints, a solder reservoir, a chip welding area, a busbar channel, and a molding compound. Cable resistance welding joints are provided at both ends of the metal plate. Inside the cable resistance welding joints, two rectangular solder reservoirs are symmetrically arranged along the length of the metal plate, forming a chip welding area between the two solder reservoirs. A busbar channel is provided through the metal plate at the corresponding position of the solder reservoir for the busbar to pass through and weld together with the solder in the solder reservoir. The metal plate, solder reservoir, chip welding area, and cable resistance welding joints are completely encapsulated by the molding compound.

[0007] According to the above technical solution, the rectangular tin storage tank is a downwardly recessed tank structure, which is recessed along the thickness direction of the metal plate to form a tin storage space.

[0008] According to the above technical solution, the surface of the chip welding area is provided with a silver plating layer or a tin plating layer.

[0009] According to the above technical solution, the busbar channel is arranged through the metal plate in a direction perpendicular to the surface of the metal plate.

[0010] According to the above technical solution, the resistance welding joint of the cable is separated from the chip welding area by a solder reservoir, so that the transient heat generated by resistance welding does not directly act on the chip welding area.

[0011] According to the above technical solution, the chip welding area includes two independent welding areas on the left and right. The two welding areas are arranged in correspondence with two solder storage tanks. The metal plate between the two welding areas maintains continuous conductivity to form a dual-chip serial path.

[0012] According to the above technical solution, the solder storage tank includes two outer rectangular solder storage tanks and a narrow middle solder storage tank located therebetween. The three solder storage tanks are arranged at equal intervals along the transverse direction to guide the molten solder to spread evenly to the left and right chip soldering areas during reflow soldering.

[0013] According to the above technical solution, the metal plate surrounding the chip welding area is provided with a heat-limiting boundary to restrict the diffusion range of molten solder.

[0014] Compared with existing technologies, the beneficial effects achieved by this invention are as follows: This invention, through a partitioned structural layout comprising cable resistance soldering joints, a rectangular solder reservoir, a chip soldering area, and busbar through-slots, isolates the transient high temperatures generated by the cable resistance soldering joints from the solder reservoir, preventing direct heat transfer to the chip soldering area and effectively reducing the thermal shock risk of the chip solder joints. The solder reservoir of this invention employs a symmetrically arranged rectangular groove structure, allowing molten solder to diffuse in a controlled manner into the chip soldering area during heating, improving the uniformity of the solder layer thickness and reducing the probability of cold solder joints. The busbar through-slots are arranged correspondingly to the solder reservoir, enabling the busbar to be soldered simultaneously using the molten solder in the solder reservoir after insertion, improving the wettability and conductive area of ​​the busbar solder joints.

[0015] In the dual-chip structure embodiment, the chip soldering area is divided into two independent soldering regions, left and right. A molten solder guiding structure composed of a three-chamber solder reservoir ensures that the molten solder is evenly distributed along the central channel to both sides during reflow, achieving consistent solder joint formation at both chip locations and improving the current balance capability of the series circuit. The overall structure of this invention is ultimately encapsulated by a plastic encapsulation, forming a closed protective interface between the metal plate, solder reservoir, cable solder joints, and chip soldering area, significantly improving solder joint stability and environmental adaptability. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 is a schematic diagram of the overall structure of a cable resistance welding module proposed in this invention.

[0017] In the diagram: 1. Cable resistance solder joint, 2. Metal plate, 3. Solder reservoir, 4. Busbar channel, 5. Molded enclosure, 6. Chip soldering area. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: Referring to Figure 1: A cable resistance welding module, this example provides a cable resistance welding photovoltaic module. The overall structure consists of a metal plate 2, cable resistance welding joints 1, solder reservoirs 3, chip welding area 6, busbar channel 4, and a molding compound 5. The components are connected by a fixing structure and welding process to form an integrated encapsulation unit. The metal plate 2 is arranged in a long strip along the horizontal direction, with cable resistance welding joints 1 processed at its left and right ends. The cable generates an instantaneous molten nugget through resistance welding in this area, forming a stable conductive connection between the cable and the metal plate 2. Inside the cable resistance welding joints 1, two rectangular solder reservoirs 3 are symmetrically formed along the length of the metal plate 2. The solder reservoirs 3 are recessed structures with a depth moderately reduced relative to the base surface of the metal plate 2, giving them the dual functions of solder storage and heat buffering during heating, thus delaying the rapid transfer of heat to the chip welding joints during the resistance welding heating stage.

[0020] The flat metal area between the two solder reservoirs 3 forms the chip soldering area 6. The surface of the chip soldering area 6 is treated with silver or tin plating to enhance solder wetting and thermal uniformity. The solder pre-stored in the solder reservoirs 3 melts during the reflow heating stage and extends inward along the chip soldering area 6, filling the bottom soldering interface of the chip and ensuring a stable and consistent solder layer thickness. The chip soldering area 6 and the solder reservoirs 3 are arranged continuously in the transverse direction, allowing the molten solder to flow naturally to the chip solder joints after heating, improving solder coverage and reducing the probability of cold solder joints.

[0021] A busbar channel 4 is installed through the metal plate 2 at the center of the solder reservoir 3. After passing through the busbar channel 4, the busbar completes reflow soldering together with the molten solder in the solder reservoir 3, forming a continuous low-impedance conductive path between the busbar and the chip soldering area 6 within the metal plate 2. The cable resistance solder joint 1 is located on the outermost side of the entire structure, so that the high temperature generated during resistance soldering is blocked by the solder reservoir 3 and the metal structure, and will not directly affect the position of the chip soldering area 6, effectively reducing the risk of thermal shock to the chip solder joint. Finally, the metal plate 2, the solder reservoir 3, the chip soldering area 6, the cable solder joint 1, and the busbar channel 4 are all completely encapsulated by the molding compound 5, forming a package structure with high mechanical strength and reliable electrical insulation.

[0022] Example 2: This example further improves upon Example 1, providing a dual-chip cascaded package structure suitable for high-current bypass scenarios. The overall unit still consists of a metal plate 2, cable resistance solder joints 1, a solder reservoir 3, a chip soldering area 6, a busbar channel 4, and a molding compound 5, but the internal structural layout and molten solder conduction method are further optimized. The metal plate 2 still has a long strip structure, with cable resistance solder joints 1 at both ends. The metal thickness in the solder joint area is relatively increased to withstand the thermal load and mechanical stress of the dual-chip cascaded system under high current.

[0023] Two outer rectangular solder reservoirs 3 are arranged inside the resistance welding joint 1 of the cable, and a narrow middle solder reservoir 3 is added in the central area. The three solder reservoirs 3 are arranged equidistantly in the horizontal direction to form a "three-chamber molten solder storage and guiding structure". The middle solder reservoir 3 is smaller than the two main solder reservoirs 3. As a molten solder guiding path, it enables the molten solder in the two side solder reservoirs 3 to diffuse horizontally uniformly during heating and reflow, so that the welding surfaces on both sides of the chip welding area 6 receive the same amount of molten solder during heating.

[0024] In this embodiment, the chip soldering area 6 is divided into two independent regions, left and right. Two bypass diode chips are soldered to the two chip soldering areas 6 respectively. The two soldering areas are electrically connected in series through a continuous, non-perforated metal segment inside the metal plate 2. The three-chamber arrangement of the solder reservoir 3 and the chip soldering area 6 forms a controlled molten solder flow path during heating, allowing the molten solder to automatically diffuse to the left and right sides along the middle solder reservoir 3 during chip soldering, improving the consistency of the solder layer thickness of the two chips.

[0025] Corresponding to the three solder reservoirs 3, a through-hole duct 4 is formed in the metal plate 2. The busbar passes through the duct and, together with the solder interfaces of the left and right chip soldering areas 6, completes the solder reflow soldering. The metal plate 2 surrounding the chip soldering area 6 forms a heat-limiting boundary that is slightly higher than the solder reservoir 3. During reflow, it restricts the diffusion of molten solder to the periphery, keeping the molten solder stably within the chip soldering area 6 and the solder reservoir 3, thus improving the accuracy of solder formation. The two chip soldering areas 6 achieve a consistent solder layer thickness due to the controlled molten solder flow, enabling the series circuit to maintain low loss and thermal uniformity under high current conditions.

[0026] The resistance solder joint 1 of the cable remains outside the solder reservoir 3. Through the multi-layer thermal path barrier formed by the metal plate 2 and the solder reservoir 3, transient thermal shock to the chip soldering area 6 caused by resistance soldering heating can be avoided. Finally, the metal plate 2, the solder reservoir 3, the chip soldering area 6, the resistance solder joint 1 of the cable, and the busbar channel 4 are completely encapsulated by the molding compound 5 to complete the dual-chip serial packaging structure.

[0027] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0028] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cable resistance welding module, comprising a metal plate (2), a cable resistance welding joint (1), a solder reservoir (3), a chip welding area (6), a busbar channel (4), and a molding compound (5), characterized in that: Cable resistance welding points (1) are provided at both ends of the metal plate (2); inside the cable resistance welding points (1), two rectangular tin storage tanks (3) are symmetrically arranged along the length of the metal plate (2), and a chip welding area (6) is formed between the two tin storage tanks (3); a busbar through groove (4) is provided through the metal plate (2) at the corresponding position of the tin storage tank (3) for the busbar to pass through and to complete the welding together with the tin material in the tin storage tank (3); the metal plate (2), tin storage tank (3), chip welding area (6) and cable resistance welding points (1) are completely covered by a plastic encapsulation body (5).

2. The cable resistance welding module according to claim 1, characterized in that: The rectangular tin storage tank (3) is a downwardly recessed tank structure that is recessed along the thickness direction of the metal plate (2) to form a tin storage space.

3. The cable resistance welding module according to claim 1, characterized in that: The surface of the chip welding area (6) is provided with a silver plating layer or a tin plating layer.

4. The cable resistance welding module according to claim 1, characterized in that: The busbar channel (4) is provided through the metal plate (2) in a direction perpendicular to the surface of the metal plate (2).

5. A cable resistance welding module according to claim 1, characterized in that: The resistance welding joint (1) of the cable is separated from the chip welding area (6) by a solder reservoir (3) so that the transient heat generated by resistance welding does not directly act on the chip welding area (6).

6. A cable resistance welding module according to claim 1, characterized in that: The chip welding area (6) includes two independent welding areas on the left and right. The two welding areas are arranged in correspondence with two tin storage tanks (3). The metal plate (2) between the two welding areas is continuously conductive to form a dual-chip serial path.

7. A cable resistance welding module according to claim 6, characterized in that: The solder reservoir (3) includes two outer rectangular solder reservoirs and a narrow middle solder reservoir located therebetween. The three solder reservoirs are arranged equidistantly in the transverse direction to guide the molten solder to diffuse evenly to the left and right chip soldering areas (6) during reflow soldering.

8. A cable resistance welding module according to claim 6, characterized in that: The metal plate (2) surrounding the chip welding area (6) is provided with a heat-limiting boundary to restrict the diffusion range of molten solder.

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