A plastic film capacitor

Abstract

The utility model discloses a plastic film capacitor, including shell, capacitor core, the capacitor core is wrapped with the encapsulation layer outside, and the shell sets in the encapsulation layer outside, capacitor core is by four layer composite film laminated winding and is formed, and is provided with nanometer ceramic coating between two adjacent composite films, the end of capacitor core is connected with the lead -out electrode, and the junction of lead -out electrode and capacitor core is provided with reinforcing contact subassembly, and the insulating cover is set up on lead -out electrode, the centre of capacitor core forms the diameter 2 5mm's hole channel, and the heat conduction core column is inserted in the hole channel. The utility model discloses through setting up nanometer ceramic layer between composite film, improves the pressure resistance and thermal stability, through setting up reinforcing contact subassembly, increases the contact area between electrode and capacitor core, prolongs the service life, through setting up the heat conduction column core, cooperates with the radiating fin, has improved the heat dissipation performance, through setting up the insulating cover, has improved the stability.

Description

Technical Field

[0001] This utility model relates to a capacitor, and more particularly to a plastic film capacitor, belonging to the field of electronic component technology. Background Technology

[0002] Plastic film capacitors are widely used in electronic equipment, power systems, and other fields due to their advantages such as small size, large capacitance, and low loss. However, existing plastic film capacitors still have some drawbacks: limited lifespan with rapid capacitance decay after long-term use; limited withstand voltage, making them prone to dielectric breakdown; poor capacitance stability, greatly affected by temperature; susceptible to environmental influences, with high humidity leading to electrode corrosion; and poor high-frequency performance, especially at high temperatures.

[0003] These problems mainly stem from unreasonable capacitor structural design, such as insufficiently secure connections between electrodes and leads, and poor sealing and heat dissipation in the packaging structure. Therefore, it is necessary to improve the structure of plastic film capacitors to enhance their performance and reliability. Utility Model Content

[0004] To address the shortcomings of the aforementioned technologies, this invention provides a plastic film capacitor. It aims to solve the problems of short lifespan, limited voltage withstand capability, poor capacitance stability, and susceptibility to environmental influences in existing plastic film capacitors.

[0005] To solve the above technical problems, the technical solution adopted by this utility model is: a plastic film capacitor, including a shell and a capacitor core, the capacitor core being wrapped with an encapsulation layer, and the shell being disposed outside the encapsulation layer; The capacitor core is made of four layers of composite film stacked and wound together, with a nano-ceramic coating between adjacent composite film layers; The capacitor core is connected to the end of the lead electrode, and a reinforced contact assembly is provided at the connection between the lead electrode and the capacitor core. An insulating sleeve is fitted on the lead electrode. A channel with a diameter of 2-5mm is formed in the center of the capacitor core, and a heat-conducting core column is inserted into the channel.

[0006] Preferably, the heat-conducting core is a ceramic core or a nickel-plated copper core, and the surface of the nickel-plated copper core is coated with an aluminum oxide insulating layer with a thickness of 10-15μm.

[0007] Preferably, the thickness of the nano-ceramic coating is 5-15 μm, and its material is barium titanate or lead zirconate titanate.

[0008] Preferably, the reinforced contact assembly includes a gold-plated layer disposed at the end of the capacitor core and a connecting piece connected to the gold-plated layer. The connecting piece is welded to the lead electrode, and the thickness of the gold-plated layer is 50-100μm.

[0009] Preferably, the composite film includes a base film layer and metallized electrode layers disposed on both sides of the base film layer.

[0010] Preferably, the base film layer is a biaxially oriented polypropylene film with a thickness of 2-10 μm, and the metallized electrode layer is an aluminum-zinc alloy layer with a thickness of 50-200 nm.

[0011] Preferably, the outer casing is made of aluminum alloy, with a moisture-proof coating on the inner wall and heat dissipation fins on the outer wall.

[0012] Preferably, the encapsulation layer is a dense epoxy resin layer with a thickness of 0.5-2 mm.

[0013] Preferably, the insulating sleeve is made of silicone rubber.

[0014] Compared with the prior art, the utility model has the following beneficial effects: 1) By setting a nano-ceramic coating between two adjacent composite film layers, the voltage withstand capability and thermal stability of the capacitor are improved, and the risk of dielectric breakdown is reduced; 2) The use of reinforced contact components increases the contact area between the lead-out electrodes and the capacitor core, improving connection reliability and extending the service life of the capacitor; 3) By setting the heat-conducting core pillars to cooperate with the heat dissipation fins of the outer shell, the heat dissipation performance of the capacitor is significantly improved, thus improving its performance during high-frequency operation; 4) By installing an insulating sleeve on the lead-out electrodes and combining it with an aluminum alloy shell, the environmental adaptability of the capacitor is improved, and the impact of mechanical damage and moisture corrosion on the capacitor performance is reduced. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0016] Figure 2 This is a schematic diagram of the capacitor core of this utility model.

[0017] Figure 3 This is a schematic diagram of the structure of the reinforced contact assembly of this utility model.

[0018] In the diagram: 1. Outer shell; 2. Capacitor core; 3. Encapsulation layer; 4. Lead electrode; 5. Reinforced contact assembly; 6. Insulating sleeve; 11. Moisture-proof coating; 12. Heat dissipation fins; 21. Nano-ceramic coating; 22. Composite film; 23. Thermally conductive core; 51. Gold spray layer; 52. Connecting piece. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] Example 1

[0021] like Figure 1 The plastic film capacitor shown includes a shell 1 and a capacitor core 2. The capacitor core 2 is wrapped with an encapsulation layer 3, and the shell 1 is disposed outside the encapsulation layer 3. The capacitor core 2 is formed by stacking and winding four layers of composite film 22, with a nano-ceramic coating 21 between adjacent composite film layers; By applying a nano-ceramic coating, the coating exhibits excellent insulation and high-temperature resistance, which can improve the overall dielectric strength, reduce the risk of breakdown, enhance thermal conductivity, and accelerate internal heat dissipation. Preferably, the capacitor core 2 is connected to the end of the lead electrode 4, and a reinforcing contact component 5 is provided at the connection between the lead electrode 4 and the capacitor core 2. An insulating sleeve 6 is fitted on the lead electrode 4. By incorporating reinforced contact components, the stability and reliability of current transmission are ensured; by adding an insulating sleeve, the capacitor's shock resistance and insulation performance are further enhanced.

[0022] like Figure 2 As shown, a channel with a diameter of 2-5mm is formed in the center of the capacitor core 2, and a heat-conducting core column 23 is inserted into the channel.

[0023] For cylindrical capacitor cores, a 2-5mm hole is pre-drilled in the center during winding to insert the heat-conducting core column; The thermally conductive core post 23 is either a ceramic core post or a nickel-plated copper core post. The surface of the nickel-plated copper core post is coated with an aluminum oxide insulating layer with a thickness of 10-15μm. The ceramic core post is made of aluminum nitride and is suitable for high-voltage scenarios (>1kV), with no risk of leakage current due to its insulation properties; the nickel-plated copper core post is suitable for medium and low voltage high-power scenarios. The heat-conducting core is in direct contact with the high-temperature area at the center of the capacitor core. Heat is quickly conducted through the heat-conducting core to the gold-plated layers at both ends of the capacitor core, and then transferred to the encapsulation layer, thereby reducing the temperature rise at the center of the capacitor core.

[0024] The nano-ceramic coating 21 has a thickness of 5-15 μm and is made of barium titanate or lead zirconate titanate.

[0025] Nano-ceramic coatings possess excellent dielectric properties and high-temperature resistance, which can improve the voltage withstand capability and thermal stability of capacitors.

[0026] The nano-ceramic coating forms a synergistic system with the composite film, electrode, and encapsulation layer. It solves the problem of withstand voltage by improving dielectric strength, solves the problem of high-frequency temperature rise by enhancing thermal conduction, and solves the problem of moisture corrosion by dense barrier.

[0027] Furthermore, such as Figure 3As shown, the reinforced contact assembly 5 includes a gold-plated layer 51 disposed at the end of the capacitor core and a connecting piece 52 connected to the gold-plated layer. The connecting piece 52 is welded to the lead electrode 4. The thickness of the gold-plated layer 51 is 50-100μm.

[0028] By increasing the thickness of the gold plating layer and adding connecting tabs, the contact area can be increased, the connection reliability can be improved, and desoldering due to thermal expansion and contraction can be prevented.

[0029] Preferably, the composite film 22 includes a base film layer and metallized electrode layers disposed on both sides of the base film layer. The base film layer is a biaxially oriented polypropylene film with a thickness of 2-10 μm, and the metallized electrode layers are aluminum-zinc alloy layers with a thickness of 50-200 nm.

[0030] Using biaxially oriented polypropylene film as the base film layer provides high mechanical strength and insulation properties; the aluminum-zinc alloy electrode layer enhances the conductivity and corrosion resistance of the electrodes.

[0031] Preferably, the outer casing 1 is made of aluminum alloy, with a moisture-proof coating 11 on the inner wall and heat dissipation fins 12 on the outer wall. The aluminum alloy casing has good heat dissipation performance and mechanical strength. The moisture-proof coating uses nano-silica sol waterproof material, which can prevent moisture intrusion and reduce the damage to the internal metallized film caused by water vapor intrusion during use. The heat dissipation fins can increase the heat dissipation area and improve the heat dissipation effect.

[0032] Encapsulation layer 3 is a dense epoxy resin layer with a thickness of 0.5-2mm. The encapsulation layer is formed using a megasonic vibration-assisted negative pressure potting process. This process reduces air bubbles within the encapsulation layer, improves its density, and enhances the capacitor's resistance to high humidity and high current.

[0033] Preferably, the insulating sleeve 6 is made of silicone rubber. Silicone rubber has good elasticity and insulation properties.

[0034] Example 2

[0035] The difference between this embodiment and Embodiment 1 is that: The surface of the capacitor core is coated with a layer of nano-waterproof material to form a waterproof spray layer; The waterproof spray layer uses nano-silica sol waterproof material. Applying this layer to the outside of the capacitor core improves the product's moisture resistance and reduces the damage to the internal metallized film caused by moisture intrusion during use. It offers advantages such as low cost, ease of operation, high efficiency, and high reliability.

[0036] The outer shell is made of resin, and its surface has several grooves with a U-shaped cross-section. The grooves are arranged in a linear array on the surface of the shell, and the depth of the grooves is 2mm.

[0037] By creating grooves, several grooves are cut on the outer surface of the resin shell, effectively increasing the surface area of ​​the capacitor and improving its heat dissipation performance.

[0038] A protective layer is provided on the outer wall of the capacitor core. The protective layer is welded to the lead-out electrodes.

[0039] The protective layer includes an inner insulating plastic sheet and an outer insulating plastic sheet. A cross-shaped mesh plate is fixedly connected between the inner and outer insulating plastic sheets. The inner insulating plastic sheet is fixedly connected to the outer wall of the capacitor core by non-adhesive.

[0040] When a capacitor is impacted, the protective layer is the first to be hit. The outer insulating plastic sheet transmits the force to the internal cross-shaped mesh plate. Due to the shock absorption of the cross-shaped mesh plate structure and the buffering effect of the plastic mesh plate material itself, the force acting on the capacitor core is greatly weakened, thus protecting the capacitor core and making it less prone to damage during use.

[0041] The lead-out electrodes are not only conductive channels, but also auxiliary paths for heat dissipation from the core. In particular, at the connection between the gold-plated layers at both ends and the electrodes, a thermally conductive silicone rubber coating with a thickness of 10-20μm is applied to the non-conductive area of ​​the lead-out electrodes, i.e. the contact section between the lead-out electrodes and the encapsulation layer.

[0042] Thermally conductive silicone rubber coating can fill the tiny gap between the lead-out electrode and the encapsulation layer, reducing gap thermal resistance and enabling the heat from the electrode to be transferred to the encapsulation layer more efficiently, thus enhancing heat dissipation.

[0043] The lead-out electrode adopts a sheet electrode. The contact end between the electrode and the gold-plated layer is designed as a Φ5-8mm circular metal sheet made of tin-plated brass. It is connected to the gold-plated layer by ultrasonic welding to increase the contact area. Increasing the contact area can reduce the contact thermal resistance, allowing the heat from the capacitor core to be quickly transferred to the circuit board or external heat dissipation structure through the electrodes.

[0044] The purpose of this invention is to provide a plastic film capacitor that improves voltage resistance and thermal stability by setting a nano-ceramic layer between composite films; extends service life by setting a reinforced contact component to increase the contact area between the electrodes and the capacitor core; improves heat dissipation performance by setting a heat-conducting core in conjunction with heat dissipation fins; and improves stability by setting an insulating sleeve. The reasonable structural design effectively improves the service life, capacitance stability, and reliability of the plastic film capacitor, expanding its application range.

[0045] The above embodiments are not intended to limit the present utility model, nor is the present utility model limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the technical solution of the present utility model are also within the protection scope of the present utility model.

Claims

1. A plastic film capacitor, comprising a casing (1) and a capacitor core (2), characterized in that: The capacitor core (2) is wrapped with an encapsulation layer (3), and the outer shell (1) is disposed outside the encapsulation layer (3); The capacitor core (2) is formed by stacking and winding four layers of composite film (22), and a nano-ceramic coating (21) is provided between two adjacent composite film layers. The capacitor core (2) is connected to the end of the lead electrode (4), and a reinforced contact assembly (5) is provided at the connection between the lead electrode (4) and the capacitor core (2). An insulating sleeve (6) is fitted on the lead electrode (4). The center of the capacitor core (2) has a channel with a diameter of 2-5 mm, and a heat-conducting core column (23) is inserted into the channel.

2. The plastic film capacitor according to claim 1, characterized in that: The heat-conducting core (23) is a ceramic core or a nickel-plated copper core, and the surface of the nickel-plated copper core is coated with an aluminum oxide insulating layer with a thickness of 10-15μm.

3. The plastic film capacitor according to claim 1, characterized in that: The thickness of the nano-ceramic coating (21) is 5-15 μm, and its material is barium titanate or lead zirconate titanate.

4. The plastic film capacitor according to claim 1, characterized in that: The reinforced contact assembly (5) includes a gold-plated layer (51) disposed at the end of the capacitor core and a connecting piece (52) connected to the gold-plated layer. The connecting piece (52) is welded to the lead electrode (4). The thickness of the gold-plated layer (51) is 50-100 μm.

5. The plastic film capacitor according to claim 1, characterized in that: The composite film (22) includes a base film layer and metallized electrode layers disposed on both sides of the base film layer.

6. The plastic film capacitor according to claim 5, characterized in that: The base film layer is a biaxially oriented polypropylene film with a thickness of 2-10 μm, and the metallized electrode layer is an aluminum-zinc alloy layer with a thickness of 50-200 nm.

7. The plastic film capacitor according to claim 1, characterized in that: The outer shell (1) is made of aluminum alloy material, with a moisture-proof coating (11) on its inner wall and heat dissipation fins (12) on its outer wall.

8. The plastic film capacitor according to claim 1, characterized in that: The encapsulation layer (3) is a dense epoxy resin layer with a thickness of 0.5-2 mm.

9. The plastic film capacitor according to claim 1, characterized in that: The insulating sleeve (6) is made of silicone rubber.

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