High-temperature-resistant resonant film capacitor

Abstract

The utility model discloses a high-temperature-resistant resonant film capacitor, which comprises a shell, a capacitor roll core and a tinned lead-out wire, epoxy resin glue is encapsulated at the upper part of the capacitor roll core in the shell, and high-heat-conductivity silica gel is encapsulated at the lower part of the capacitor roll core in the shell and is used for insulating and sealing; the capacitor roll core is formed by winding a polyester double-sided metalized aluminum film and two layers of metalized polypropylene aluminum films which are sequentially stacked from top to bottom, a gap is reserved between an upper first metal aluminum layer and a lower first metal aluminum layer of the polyester double-sided metalized aluminum film, and gaps are reserved at two ends of a second metal aluminum layer of the metalized polypropylene aluminum films. And the second metal aluminum layers of the two metalized polypropylene aluminum films are oppositely arranged. According to the utility model, the equivalent internal resistance can be reduced by 15 + / -1%, the temperature resistance can be maximally improved to 125 DEG C, the ripple current capability can be improved by about 15%, heat in the core can be effectively dissipated, heat balance can be quickly achieved, the requirement of the 800V silicon carbide charging pile field for the high-temperature-resistant and high-ripple-current-capability resonant film capacitor can be effectively met, and the service life of the capacitor is prolonged. Meanwhile, the size is not increased.

Description

Technical Field

[0001] This utility model relates to the field of thin film capacitor technology, and in particular to a high-temperature resistant resonant thin film capacitor specifically designed for high ripple current in new energy charging piles. Background Technology

[0002] Film capacitors have high reliability, excellent frequency characteristics, and low dielectric loss, and have been rapidly developed from the original home appliance field to fields such as new energy charging piles.

[0003] Existing common resonant thin-film capacitors use additional Figure 5 The metal film structure consists of a light film (polypropylene film) 5, a double-sided metallized aluminum polyester film 6, and a layer of metallized polypropylene aluminum film 7, layered sequentially from top to bottom. Its maximum temperature resistance is 85℃, and its ripple current carrying capacity is approximately 0.96A per meter. The capacitor core and outer shell are encapsulated with epoxy resin 1, which has a thermal conductivity of 0.2. Therefore, existing ordinary resonant film capacitors have high equivalent series resistance (ESR), low temperature resistance, low ripple current carrying capacity, and poor heat dissipation, failing to meet the requirements of new energy charging piles.

[0004] Currently, the equivalent series resistance (ESR) is usually reduced by increasing the size of the film capacitor. However, customers are now demanding smaller and smaller sizes, and this solution can no longer meet their requirements. Therefore, resonant film capacitors with high temperature resistance and high ripple current have strong market competitiveness without increasing the size. Utility Model Content

[0005] To address the problems of high equivalent series resistance (ESR), low temperature resistance, low ripple current capability, and poor heat dissipation in existing ordinary resonant film capacitors, this invention provides a high-temperature resistant resonant film capacitor. By improving the insulating and sealing materials and the capacitor core structure, the ESR of the high-temperature resistant resonant film capacitor can be reduced by about 15%, the temperature resistance can be increased to a maximum of 125℃, and the ripple current capability can be increased by about 15%. This effectively dissipates heat from the core, allowing it to reach thermal equilibrium more quickly.

[0006] To achieve the above objectives, this utility model provides a high-temperature resistant resonant film capacitor, comprising a shell, a capacitor core disposed within the shell, and tin-plated leads inserted on the left and right sides of the upper end of the capacitor core. The feature is that: the upper part of the capacitor core inside the shell is encapsulated with epoxy resin for insulation and sealing, and the lower part of the capacitor core inside the shell is encapsulated with high thermal conductivity silicone for insulation and sealing.

[0007] The capacitor core is formed by winding a double-sided metallized aluminum film of polyester and two layers of metallized polypropylene aluminum film stacked from top to bottom. The double-sided metallized aluminum film of polyester includes a polyester film and a first aluminum layer plated on the upper and lower surfaces of the polyester film. A gap is left in the middle of the first aluminum layer on the upper and lower surfaces. The metallized polypropylene aluminum film includes a polypropylene film and a second aluminum layer plated on the upper or lower surface of the polypropylene film. A gap is left at both ends of the second aluminum layer. The second aluminum layers of the two metallized polypropylene aluminum films are arranged opposite to each other.

[0008] Furthermore, the thermal conductivity of the high thermal conductivity silicone is 3±0.5w / mk.

[0009] The thermal conductivity of high thermally conductive silicone is 15 times that of epoxy resin, which greatly improves the heat dissipation capacity of the product, allowing the heat inside the capacitor core to be dissipated more effectively. The capacitor core is more likely to reach thermal equilibrium, thereby achieving the ability to withstand high temperature and high ripple current.

[0010] Furthermore, the volume ratio of the epoxy resin adhesive to the high thermal conductivity silicone adhesive is set to 30-40:60-70.

[0011] Furthermore, gaps S1 and S2 are left in the middle of the first aluminum layer on the upper and lower surfaces of the polyester double-sided metallized aluminum film, respectively. The positions of S1 and S2 are corresponding to each other, and S1=S2, 2.45≤S1≤2.55mm.

[0012] The two ends of the second aluminum metal layer are respectively left with gaps S3 and S4, and S3=S4, 0.95≤S3≤1.05mm.

[0013] Furthermore, both ends of the capacitor winding are provided with a gold plating layer, and the gold plating layer is made of zinc-tin alloy.

[0014] Furthermore, the outer shell is made of PPS flame-retardant plastic, which has a flame retardant rating of UL94V-0.

[0015] Compared with existing technologies, the beneficial effects of this utility model are as follows: 1. By using two metallized polypropylene aluminum films instead of a light film, the equivalent series resistance (ESR) of the resonant film capacitor can be reduced by 15±1%, greatly reducing the temperature rise of the film capacitor without affecting its withstand voltage; 2. The utility model uses high thermal conductivity silicone potting and PPS flame-retardant plastic shell, which greatly improves the heat dissipation capacity of the film capacitor, allowing the heat inside the capacitor core to be dissipated more effectively, making it easier for the capacitor core to reach thermal equilibrium, thereby achieving high temperature and high ripple current resistance; 3. The temperature resistance of the resonant film capacitor of this utility model can be increased to a maximum of 125℃, and the ripple current resistance can be increased by about 15%, which can effectively solve the demand for high temperature and high ripple current resonant film capacitors in the field of 800V silicon carbide charging piles, without increasing the size, significantly shortening the charging time, and providing a fast charging experience. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the metal film layer structure before the capacitor core is wound according to an embodiment of this utility model;

[0017] Figure 2 This is a schematic diagram of the cross-sectional structure of an embodiment of the present utility model;

[0018] Figure 3 This is a schematic diagram of the longitudinal section structure of an embodiment of the present utility model;

[0019] Figure 4 This is a schematic diagram of the cross-sectional structure of an existing resonant thin-film capacitor;

[0020] Figure 5 This is a schematic diagram of the metal film structure of an existing resonant thin-film capacitor before the capacitor core is wound.

[0021] In the diagram: 1. Epoxy resin adhesive, 2. Outer shell, 3. Capacitor winding core, 301. Gold spray layer, 4. Silicone, 5. Optical film (polypropylene film), 6. Polyester double-sided metallized aluminum film, 601. Polyester film, 602. First metallized aluminum layer, 7. Metallized polypropylene aluminum film, 701. Polypropylene film, 702. Second metallized aluminum layer, 8. Tin-plated lead wire. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] like Figure 1 ,2 As shown in Figures 1 and 3, this embodiment of the utility model includes a housing 2, a capacitor core 3 disposed inside the housing 2, and tin-plated lead wires 8 inserted on the left and right sides of the upper end of the capacitor core 3. The upper part of the capacitor core 3 inside the housing 2 is filled with epoxy resin 1. When the epoxy resin 1 is heat-sealed, it is integrated with the housing to form an integral structure for insulation and sealing. The lower part of the capacitor core 3 inside the housing 2 is filled with high thermal conductivity silicone 4 for insulation and sealing. The thermal conductivity of the high thermal conductivity silicone is 3±0.5w / mk.

[0024] The thermal conductivity of the high thermal conductivity silicone 4 is 15 times that of the epoxy resin 1, which greatly improves the heat dissipation capacity of the product, allowing the heat inside the capacitor core 3 to be dissipated more effectively. The capacitor core 3 can more easily reach thermal equilibrium, thereby achieving the ability to withstand high temperature and high ripple current.

[0025] The capacitor core 3 is formed by winding a double-sided metallized aluminum polyester film 6 and two layers of metallized polypropylene aluminum film 7, which are stacked from top to bottom. The double-sided metallized aluminum polyester film 6 includes a polyester film 601 and a first aluminum metal layer 602 plated on the upper and lower surfaces of the polyester film 601. There is a gap between the first aluminum metal layer 602 on the upper and lower surfaces. The metallized polypropylene aluminum film 7 includes a polypropylene film 701 and a second aluminum metal layer 702 plated on the upper or lower surface of the polypropylene film 701. There is a gap at both ends of the second aluminum metal layer 702. The second aluminum metal layers 702 of the two metallized polypropylene aluminum films 7 are arranged opposite to each other.

[0026] Furthermore, the volume ratio of epoxy resin 1 to high thermal conductivity silicone 4 is set to 30-40:60-70.

[0027] Furthermore, gaps S1 and S2 are left in the middle of the first aluminum layer 602 on the upper and lower surfaces of the polyester double-sided metallized aluminum film 6, respectively. The positions of S1 and S2 are corresponding to each other, and S1=S2=2.5mm.

[0028] The two ends of the second aluminum layer 702 have gaps S3 and S4 respectively, and S3=S4=1mm.

[0029] Furthermore, both ends of the capacitor winding core 3 are provided with a gold spray layer 301, which is made of zinc-tin alloy.

[0030] Furthermore, the outer shell 2 is made of PPS flame-retardant plastic, which has a flame retardant rating of UL94V-0.

[0031] According to tests conducted by an analysis and testing institution in Qingdao, the equivalent internal resistance of the high-temperature resonant film capacitor in this embodiment was reduced by 15.1%, the temperature resistance was increased to a maximum of 125℃, and the ripple current capability was improved by about 15.5%.

[0032] This embodiment effectively solves the demand for resonant thin-film capacitors with high temperature and high ripple current resistance in the field of 800V silicon carbide charging piles, while not increasing the size, significantly shortening the charging time, and providing a fast charging experience. It is worthy of widespread application.

[0033] The above are merely preferred embodiments of this utility model. It should be noted that, for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this utility model, and these improvements and substitutions should also be considered within the protection scope of this utility model.

Claims

1. A high-temperature resistant resonant thin-film capacitor, comprising a housing, a capacitor core disposed within the housing, and tin-plated leads inserted on the left and right sides of the upper end of the capacitor core, characterized in that: The upper part of the capacitor winding core in the shell is filled with epoxy resin glue for insulation and sealing, and the lower part of the capacitor winding core in the shell is filled with high-thermal-conductivity silica gel for insulation and sealing; The capacitor winding core is formed by winding polyester double-sided metalized aluminum film and two layers of metalized polypropylene aluminum film from top to bottom, the polyester double-sided metalized aluminum film comprises a polyester film and a first metal aluminum layer plated on the upper and lower surfaces of the polyester film, and gaps are left in the first metal aluminum layer on the upper and lower surfaces, the metalized polypropylene aluminum film comprises a polypropylene film and a second metal aluminum layer plated on the upper or lower surface of the polypropylene film, and gaps are left at the two ends of the second metal aluminum layer, and the second metal aluminum layers of the two layers of metalized polypropylene aluminum film are oppositely arranged.

2. The high temperature resonant thin film capacitor of claim 1, wherein: The high-thermal-conductivity silica gel has a thermal conductivity of 3±0.5 w / m.k.

3. The high temperature resonant thin film capacitor of claim 1, wherein: The volume ratio of the epoxy resin glue to the high-thermal-conductivity silica gel is set to 30-40:60-70.

4. The high temperature resonant thin film capacitor of claim 1, wherein: The first metal aluminum layer on the upper and lower surfaces of the polyester double-sided metalized aluminum film has gaps S1 and S2 left in the middle, respectively, S1 and S2 are oppositely arranged on the upper and lower surfaces, S1=S2, and 2.45≤S1≤2.55 mm; The second metal aluminum layer has gaps S3 and S4 left at the two ends, respectively, S3=S4, and 0.95≤S3≤1.05 mm.

5. The high temperature resonant thin film capacitor of claim 1, wherein: The capacitor winding core is provided with a spray gold layer at the two ends, and the spray gold layer is made of zinc-tin alloy.

6. The high temperature resonant thin film capacitor of claim 1, wherein: The shell is made of PPS flame-retardant plastic, and the PPS flame-retardant plastic has a flame-retardant grade of UL94V-0.

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