Thin film capacitor

Abstract

The invention provides a thin-film capacitor. The thin-film capacitor comprises a shell, a thin-film core, a lap joint busbar, a busbar terminal, a soft sealing element and a potting material, the shell is provided with a mounting cavity, and a large opening and a small opening which are communicated with the mounting cavity; the thin film core is mounted in the mounting cavity; the lap joint busbar is connected with the metal spraying surface of the thin film core; the busbar terminal is fixedly connected with the lap-joint busbar and extends out of the small opening; the soft sealing element wraps the busbar terminal, and the outer surface of the soft sealing element is in contact with the inner wall of the small opening so as to realize sealing between the busbar terminal and the small opening; and the potting material is injected into the mounting cavity through the large opening so as to package the thin film core, the lap joint busbar and the busbar terminal. The film capacitor is simple in structure, can omit a manual gluing step, greatly improves the production and filling efficiency, is reliable in sealing, effectively reduces the glue leakage reject ratio, and is suitable for a complex terminal scene.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, and more specifically to a thin-film capacitor. Background Technology

[0002] Film capacitors are widely used in electronic equipment, industrial control, automobiles, and many other fields. Their typical structure includes a capacitor core (containing plates, dielectric, and a metal layer sprayed onto both ends), lead electrodes (such as leads, solder pads, or busbars), a package casing, and a filling resin (such as epoxy resin). In film capacitors where the busbar penetrates the package casing, leakage at the interface between the electrodes and the package casing must be avoided during resin filling.

[0003] In existing technologies, the solution to the aforementioned material leakage problem is as follows: because the part of the busbar extending outside the outer shell needs to be made into a complex shape to match the client, it is impossible to assemble a sealing plug on the busbar. Therefore, a cover plate is placed at the large opening end of the outer shell and sealed by applying adhesive, and then material is poured in through a funnel from the small opening. However, this solution has significant drawbacks: on the one hand, due to the special nature of the product structure, automatic adhesive application is often not possible, and the cover plate sealing requires manual operation, resulting in low production efficiency; on the other hand, the funnel filling method at the small opening is cumbersome to operate and also suffers from low filling efficiency, making it difficult to meet the needs of large-scale production. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the aforementioned technologies. Therefore, the objective of the present invention is to provide a film capacitor with a simple structure, which eliminates the need for manual glue application, significantly improves production and filling efficiency, provides reliable sealing, effectively reduces glue leakage defects, and is suitable for complex terminal scenarios.

[0005] To achieve the above objectives, the present invention provides a thin-film capacitor, comprising: a shell, a thin-film core, a lap busbar, busbar terminals, a flexible sealant, and a potting compound; The outer casing is provided with a mounting cavity, and a large opening and a small opening communicating with the mounting cavity; The thin film core is installed inside the mounting cavity; The overlapping busbar connects to the gold-plated surface of the thin film core; The busbar terminal is fixedly connected to the overlapping busbar and extends out from the small opening; The flexible seal covers the busbar terminal, and the outer surface of the flexible seal contacts the inner wall of the small opening to achieve a seal between the busbar terminal and the small opening; The potting compound is injected into the mounting cavity through the large opening to encapsulate the film core, the overlapping busbar, and the busbar terminals.

[0006] This invention discloses a film capacitor designed for complex terminal products. It optimizes the traditional method of sealing with a large opening and filling with a small opening to sealing with a small opening and filling with a large opening. Reliable sealing of the small opening is achieved by wrapping the busbar terminals with a soft sealing element. Simultaneously, the integrated busbar is improved into a separate connection structure where the busbar and busbar terminals overlap, making it more suitable for complex terminal shapes. This film capacitor has a simple structure, eliminating the need for manual glue application, significantly improving production and filling efficiency, ensuring reliable sealing, effectively reducing glue leakage defects, and making it suitable for complex terminal scenarios.

[0007] In addition, a thin-film capacitor according to the above embodiments of the present invention may also have the following additional technical features: Optionally, the material of the soft seal is at least one of silicone, rubber, thermoplastic elastomer or thermoplastic polyurethane elastomer.

[0008] Furthermore, the soft seal and the busbar terminal are covered and fixed by in-mold injection molding, in-mold vulcanization, or separate assembly.

[0009] Optionally, the overlapping busbar is connected to the gold-plated surface of the film core by laser welding, soldering, or riveting.

[0010] Optionally, the overlapping busbar and the busbar terminal are fixedly connected by laser welding, soldering or riveting.

[0011] Optionally, the overlapping busbar includes a first busbar and a second busbar, the first busbar and the second busbar being connected to the two gold-plated surfaces of the film core in a one-to-one correspondence; the busbar terminal includes a third busbar and a fourth busbar, the third busbar and the fourth busbar being connected to the first busbar and the second busbar in a one-to-one correspondence, and the flexible sealing element covering the third busbar and the fourth busbar.

[0012] Furthermore, a connection gap is formed between the first busbar and the second busbar, one end of the third busbar and the fourth busbar extends into the connection gap and is connected to the first busbar and the second busbar, and an insulating element is sandwiched between the third busbar and the fourth busbar. Attached Figure Description

[0013] Figure 1 An exploded view of a thin-film capacitor according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a thin-film capacitor according to an embodiment of the present invention; Figure 3 for Figure 2 A structural diagram from another perspective; Figure 4 for Figure 3Sectional view along AA; Figure 5 This is a schematic diagram of the outer casing according to an embodiment of the present invention; Figure 6 for Figure 5 A structural diagram from another perspective; Explanation of reference numerals in the attached figures: 1. Outer shell, 11. Mounting cavity, 12. Large opening, 13. Small opening, 2. Film core, 3. Overlapping busbar, 3. First busbar, 31. Second busbar, 32. Busbar terminal, 4. Third busbar, 41. Fourth busbar, 42. Soft sealant, 5. Potting compound, 6. Insulating component, 7. Detailed Implementation

[0014] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0015] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0016] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0017] The following is for reference. Figures 1-6 The implementation of the thin-film capacitor proposed in the embodiments of the present invention will be described in detail.

[0018] According to an embodiment of the present invention, a film capacitor includes: a housing 1, a film core 2, a connecting busbar 3, busbar terminals 4, a flexible sealing element 5, and a potting compound 6; The outer casing 1 is provided with a mounting cavity 11, and a large opening 12 and a small opening 13 communicating with the mounting cavity 11; The thin film core 2 is installed inside the mounting cavity 11; The overlapping busbar 3 connects to the gold-plated surface of the thin film core 2; Busbar terminal 4 is fixedly connected to overlapping busbar 3 and extends out from small opening 13; The soft seal 5 covers the busbar terminal 4, and the outer surface of the soft seal 5 contacts the inner wall of the small opening 13 to achieve a seal between the busbar terminal 4 and the small opening 13. The potting compound 6 is injected into the mounting cavity 11 through the large opening 12 to encapsulate the film core 2, the overlapping busbar 3 and the busbar terminal 4.

[0019] In other words, the core of this technical solution is to adjust the division of labor between sealing and filling openings. The soft sealing component 5 directly replaces the glue sealing structure between the cover plate and the outer shell 1 in the original technology, eliminating the need for an additional cover plate and saving the tedious step of manual glue application. At the same time, the integrated busbar is split into a separate structure of overlapping busbar 3 and busbar terminal 4. During assembly, the overlapping busbar 3 is connected to the gold-plated surface of the thin-film core 2. Then, the busbar terminal 4, covered with the flexible sealant 5, is connected to the overlapping busbar 3. The assembled capacitor body, consisting of the thin-film core 2, overlapping busbar 3, busbar terminal 4, and the flexible sealant 5 covering the busbar terminal 4, is then inserted into the mounting cavity 11 through the large opening 12. The busbar terminal 4 extends from the small opening 13. The tight fit between the outer surface of the flexible sealant 5 and the inner wall of the small opening 13 achieves a seal. The potting compound 6 fills the gap between the flexible sealant 5 and the small opening 13. During the curing process, the potting compound 6 forms an interlocking structure with the flexible sealant 5, further improving the sealing reliability and fixing the capacitor body to the mounting cavity 11. This design not only solves the leakage problem and reduces the product defect rate but also significantly improves production and potting efficiency, effectively meeting the application needs of electronic equipment, automobiles, and other fields.

[0020] The overlapping busbar 3 and the film core 2, as well as the overlapping busbar 3 and the busbar terminal 4, can be connected by existing connection methods, such as welding or bonding; the soft sealing element 5 can be made of existing materials, such as rubber or silicone, and can be finished and fitted onto the busbar terminal 4 or coated onto the busbar terminal 4 by an encapsulation process; the overlapping busbar 3 and the busbar terminal 4 can be set in pairs to lead the two electrodes of the film core 2 out to the outside of the mounting cavity 11; the small opening 13 can be formed by the protrusion extending from the outer shell 1 out of the cavity.

[0021] Therefore, this film capacitor, designed for complex terminal products, optimizes the original method of sealing the large opening 12 and filling the small opening 13 into sealing the small opening 13 and filling the large opening 12. A reliable seal for the small opening 13 is achieved by wrapping the busbar terminal 4 with a soft sealing element 5. Simultaneously, the integrated busbar is improved into a separate connection structure where the overlapping busbar 3 and the busbar terminal 4 are connected, making it more suitable for complex terminal shapes. This film capacitor has a simple structure, eliminating the need for manual glue application, significantly improving production and filling efficiency, ensuring reliable sealing, effectively reducing glue leakage defects, and making it suitable for complex terminal scenarios.

[0022] Optionally, the flexible seal 5 is made of at least one of silicone, rubber, thermoplastic elastomer, or thermoplastic polyurethane elastomer. Understandably, these materials all possess excellent elastic deformation capacity and aging resistance. Utilizing the inherent flexibility of the material, the flexible seal 5 can tightly conform to the inner wall of the small opening 13 and the surface of the busbar terminal 4, filling the assembly gap. Simultaneously, these materials are resistant to high and low temperatures and chemical corrosion, adapting to temperature changes during capacitor operation and the chemical environment of the potting compound 6. This ensures the long-term stability of the sealing structure and prevents seal failure due to material aging, thereby extending the overall service life of the capacitor and meeting application requirements under different operating conditions.

[0023] Furthermore, the flexible seal 5 and the busbar terminal 4 are encapsulated and fixed through in-mold injection molding, in-mold vulcanization, or separate assembly. Understandably, different encapsulation and fixing methods adapt to different production scenarios and precision requirements. The flexible seal 5 encapsulates the busbar terminal 4 to form a robust, integrated structure, preventing relative displacement from affecting the sealing effect. In-mold injection molding and vulcanization allow the flexible seal 5 and the busbar terminal 4 to form a tightly fitting connection surface, resulting in higher sealing reliability and suitability for mass production. Separate assembly offers assembly flexibility, facilitating later maintenance or specification adjustments. All three methods ensure complete encapsulation of the busbar terminal 4 by the flexible seal 5, preventing leakage of the potting compound 6 from the connection point, while simultaneously improving assembly efficiency and reducing production difficulty.

[0024] Optionally, the overlapping busbar 3 and the gold-plated surface of the thin-film core 2 are connected by laser welding, soldering, or riveting. Understandably, laser welding and soldering enable the overlapping busbar 3 and the gold-plated surface to form a tight metallic bond, effectively reducing contact resistance and power loss, while also improving connection sealing and preventing the potting compound 6 from seeping in and affecting electrode performance. Riveting, on the other hand, achieves a tight connection through mechanical pressure; this process is simple, low-cost, and suitable for scenarios with moderate connection strength requirements. All three methods ensure the stability of the connection between the thin-film core 2 and the overlapping busbar 3, improve the reliability of the capacitor, and prevent malfunctions caused by loose connections.

[0025] Optionally, the overlapping busbar 3 and busbar terminal 4 are fixedly connected by laser welding, soldering, or riveting. Understandably, laser welding and soldering can achieve seamless connections between busbars, reducing connection resistance, ensuring smooth current transmission, and preventing localized heating from affecting capacitor performance; riveting enables quick and secure assembly and provides good vibration resistance, making it suitable for high-frequency vibration scenarios such as automobiles. This design not only accommodates the need for split busbars but also compensates for potential stability defects in split structures through reliable connections, while enriching manufacturing process options and improving product adaptability.

[0026] Optionally, the connecting busbar 3 includes a first busbar 31 and a second busbar 32, which are connected one-to-one to the two gold-plated surfaces of the thin-film core 2; the busbar terminals 4 include a third busbar 41 and a fourth busbar 42, which are connected one-to-one to the first busbar 31 and the second busbar 32, and the flexible sealing element 5 covers the third busbar 41 and the fourth busbar 42. Understandably, the paired busbar structure, corresponding to the two gold-plated surfaces of the thin-film core 2 respectively, enables independent lead-out of the two terminals, ensuring normal current flow into and out of the capacitor. The paired busbars make the current transmission path clearer and more regular, reducing signal coupling interference between the two terminals, reducing transmission loss, and effectively improving the electrical stability of the capacitor; simultaneously, the flexible sealing element 5 synchronously covers the paired busbar terminals 4, ensuring consistent sealing of the two leads and preventing overall leakage caused by the failure of a single terminal seal. Furthermore, the split-type paired busbar design allows for more flexible adjustment of the terminal structure to meet the complex shape requirements of clients, further enhancing product adaptability and production convenience. The third busbar 41 and the fourth busbar 42 can be spaced apart to achieve insulation between them.

[0027] Furthermore, a connection gap is formed between the first busbar 31 and the second busbar 32. One end of the third busbar 41 and the fourth busbar 42 extends into the connection gap and connects with the first busbar 31 and the second busbar 32. An insulating element 7 is sandwiched between the third busbar 41 and the fourth busbar 42. Understandably, one end of the first busbar 31 and the second busbar 32 are respectively connected to the two opposing gold-plated surfaces of the thin-film core 2, and the other ends converge above the thin-film core 2 to form a connection gap. This connection gap provides assembly space for the busbar docking. Simultaneously, the insulating element 7 blocks current conduction between the paired third busbar 41 and the fourth busbar 42, preventing short-circuit faults. The sandwiching of the insulating element 7 between the third busbar 41 and the fourth busbar 42 makes the structure more compact. The insulating element 7 can be insulating paper, the first busbar 31 and the second busbar 32 can be Z-shaped, and the third busbar 41 and the fourth busbar 42 can be L-shaped.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and 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. Therefore, they should not be construed as limitations on this invention.

[0029] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0033] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A thin-film capacitor, characterized in that, include: Housing, film core, overlapping busbar, busbar terminal, flexible sealant and potting compound; The outer casing is provided with a mounting cavity, and a large opening and a small opening communicating with the mounting cavity; The thin film core is installed inside the mounting cavity; The overlapping busbar connects to the gold-plated surface of the thin film core; The busbar terminal is fixedly connected to the overlapping busbar and extends out from the small opening; The flexible seal covers the busbar terminal, and the outer surface of the flexible seal contacts the inner wall of the small opening to achieve a seal between the busbar terminal and the small opening; The potting compound is injected into the mounting cavity through the large opening to encapsulate the film core, the overlapping busbar, and the busbar terminals.

2. The thin-film capacitor according to claim 1, characterized in that, The soft seal is made of at least one of silicone, rubber, thermoplastic elastomer, or thermoplastic polyurethane elastomer.

3. The thin-film capacitor according to claim 1 or 2, characterized in that, The soft seal and the busbar terminal are covered and fixed by in-mold injection molding, in-mold vulcanization, or separate assembly.

4. The thin-film capacitor according to claim 1, characterized in that, The overlapping busbar is connected to the gold-plated surface of the film core by laser welding, soldering or riveting.

5. The thin-film capacitor according to claim 1, characterized in that, The overlapping busbar and the busbar terminal are fixedly connected by laser welding, soldering or riveting.

6. The thin-film capacitor according to claim 1, characterized in that, The overlapping busbar includes a first busbar and a second busbar, which are connected to the two gold-plated surfaces of the film core in a one-to-one correspondence; the busbar terminal includes a third busbar and a fourth busbar, which are connected to the first busbar and the second busbar in a one-to-one correspondence; and the soft sealing element covers the third busbar and the fourth busbar.

7. The thin-film capacitor according to claim 6, characterized in that, A connection gap is formed between the first busbar and the second busbar. One end of the third busbar and the fourth busbar extends into the connection gap and is connected to the first busbar and the second busbar. An insulating element is sandwiched between the third busbar and the fourth busbar.

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