A high specific capacitance caseless surface mount film capacitor

Abstract

The invention discloses a high specific capacity shellless surface-mount film capacitor, which belongs to the production technology field of surface-mount film capacitors, including a capacitor core, a sheet electrode, a sealant, an insulating annular reinforcing plate and a welding metal sheet, the two ends of the capacitor core are respectively provided with a core metal plate, the annular reinforcing plate is placed outside the capacitor core, the inner walls at both ends of the annular reinforcing plate and the inner walls on both sides of the opposite sides are respectively in close contact with the outer wall of the core metal plate and the outer walls on both sides of the capacitor core, the two ends of the annular reinforcing plate are respectively provided with reinforcing plate through holes, two welding metal sheets are respectively located at the outer sides of the two ends of the annular reinforcing plate and are welded and connected with the corresponding core metal plate and the connection parts are located in the corresponding reinforcing plate through holes, the welding metal sheet and the sheet electrode are integrally formed or welded, and the sealant is coated outside the annular reinforcing plate. The invention significantly improves the specific capacity and can simultaneously ensure that the product has sufficient strength and excellent insulation, flame retardancy and vibration resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of production of surface-mounted film capacitors, and specifically relates to a caseless surface-mounted film capacitor, and more particularly to a caseless surface-mounted film capacitor with a high specific capacitance. Background Art

[0002] Organic film capacitors are capacitors made of organic film materials as dielectrics. They have the advantages of small size, light weight, and low cost. Due to their excellent performance such as self-healing properties, open circuit failure mode, and stable temperature characteristics, they are widely used in the field of military weapons and equipment. However, in recent years, with the development needs of miniaturization and lightweight of military weapons and equipment, new requirements have been put forward for small size, large capacity, and lightweight components.

[0003] Surface mount film capacitors, also known as chip film capacitors, are organic film capacitors that use chip electrodes (generally "L" shaped). This type of capacitor can fit more closely to the circuit board during installation, so it has a smaller installation volume, which is conducive to product miniaturization and lightweight.

[0004] Specific capacitance is an important indicator of capacitors. The higher the value, the more electricity a capacitor of the same volume or mass can store, or the smaller the volume or mass of the capacitor corresponding to the same amount of electricity storage. Therefore, in the application requirements of small volume, large capacity and lightweight, the larger the specific capacitance of the surface-mount film capacitor, the better.

[0005] Traditional surface-mount film capacitors are packaged in a shell (generally an insulating plastic shell) + sealant (generally epoxy resin). In order to increase the specific capacity, the capacitor core can only be reduced in thickness by reducing the thickness of the shell and the sealant without changing the core. However, reducing the thickness of the sealant will reduce the insulation sealing effect, including reducing the insulation, flame retardancy, and vibration resistance of the product. Moreover, no matter how the thickness of the shell and the sealant is reduced, the thickness of the capacitor core is the total thickness of the shell + the insulating glue. Therefore, it is difficult for traditional surface-mount film capacitors to further increase the specific capacity while ensuring reliable performance. In addition, before the sealant is poured into the shell, the capacitor core needs to be positioned using a positioning tool so that it is located in the middle of the shell, which not only increases the processing difficulty, but also the installation space reserved for the positioning tool further increases the volume of the capacitor.

[0006] If a caseless surface-mount film capacitor without a casing and with an internal structure similar to that of a traditional surface-mount film capacitor is directly used, although the specific capacitance can be increased, it is impossible to simultaneously ensure that the product has sufficient strength and excellent insulation, flame retardancy, and vibration resistance. Summary of the invention

[0007] The purpose of the present invention is to solve the above problems and provide a high specific capacity caseless surface mount film capacitor which can ensure that the product has sufficient strength and excellent insulation, flame retardancy and vibration resistance.

[0008] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0009] A high-specific-capacity shellless surface-mount film capacitor comprises a capacitor core, a sheet electrode and a sealant, wherein core metal plates are respectively arranged at two ends of the capacitor core, two sheet electrodes are respectively connected to the two core metal plates, and the sealant is coated on the outside of the capacitor core. The high-specific-capacity shellless surface-mount film capacitor also comprises an insulating annular reinforcing plate and a welding metal sheet, wherein the annular reinforcing plate is placed outside the capacitor core, the inner walls at both ends of the annular reinforcing plate are in close contact with the outer walls of the core metal plates at both ends of the capacitor core, the inner walls on the opposite sides of the annular reinforcing plate are in close contact with the outer walls on the opposite sides of the capacitor core, reinforcing plate through holes are respectively arranged at both ends of the annular reinforcing plate, and two welding metal sheets are respectively located on the outside of the two ends of the annular reinforcing plate, the welding metal sheets are welded to the corresponding core metal plates and the connection parts are located in the corresponding reinforcing plate through holes, the welding metal sheets are integrally formed or welded to the sheet electrodes, and the sealant is coated on the outside of the annular reinforcing plate.

[0010] Preferably, in order to achieve a more compact structure and reduce the volume while ensuring strength, the middle section of the welding metal sheet is recessed toward the direction close to the corresponding core metal plate and is placed in the corresponding through hole of the reinforcing plate, and a metal sheet sink groove is formed on the outer wall of the middle section of the welding metal sheet, one end of the "L"-shaped sheet electrode is located in the corresponding metal sheet sink groove, and both ends of the welding metal sheet are bent toward the direction close to the core metal plate on the opposite side to form metal plate end plates, and the metal plate end plates are in contact with the corresponding opposite side outer walls of the annular reinforcing plate, and a plurality of spaced welding grooves are provided on the middle section of the welding metal sheet near one side edge, and solder for welding to the corresponding core metal plate is provided in the welding groove.

[0011] Preferably, in order to further achieve a more compact structure while ensuring strength, the outer wall of the annular reinforcing plate corresponding to the metal plate end plate in contact with each other is thinned to form a reinforcing plate groove, and the inner wall of the metal plate end plate close to the suspended end is thinned to form an end plate thinning section, and the end plate thinning section is placed in the corresponding reinforcing plate groove so that the outer wall surface of the metal plate end plate is flush with the outer wall surfaces on the opposite sides corresponding to the annular reinforcing plate, and the sealant is coated on the outside of the welding metal sheet and does not coat the outer wall surface of the sheet electrode.

[0012] Preferably, in order to better connect the sealant and the sheet electrode into a whole to improve the sealing effect and the outer packaging strength and avoid cracking between the sealant and the sheet electrode, an interlayer space is provided in the sheet electrode and the sealant is filled in the interlayer space.

[0013] Preferably, in order to further improve the strength, the welding metal sheet and the sheet electrode are formed integrally.

[0014] Preferably, in order to provide better connection strength between the sealant and the annular reinforcement plate and the capacitor core and avoid cracking between the sealant and the annular reinforcement plate, a plurality of potting through holes are respectively provided on opposite sides of the annular reinforcement plate and the potting through holes are filled with the sealant.

[0015] Preferably, in order to further improve the connection strength and stability between the sealant and the annular reinforcement plate and the capacitor core, the potting through hole includes a first potting through hole and a second potting through hole, the center line of the first potting through hole and the center line of the second potting through hole both have an angle of 10°-60° with the opposite side surfaces of the annular reinforcement plate, the center line of the first potting through hole and the center line of the second potting through hole have an angle of 20°-120° between them, and multiple first potting through holes and multiple second potting through holes are arranged at intervals from each other.

[0016] The beneficial effects of the present invention are:

[0017] The present invention removes the outer shell and adds an annular reinforcement plate and a welding metal sheet on the basis of the structure of a traditional surface-mount film capacitor, and utilizes the annular reinforcement plate of the annular structure and the sealant to ensure that the capacitor has sufficient strength and sealing performance. The total thickness of the capacitor is mainly the thickness of the sealant. The annular reinforcement plate and the welding metal sheet are both coated in the sealant, and the thickness they occupy is the thickness of the sealant. They do not need to occupy thickness space independently, so the insulation and flame retardancy of the product can be ensured to be unaffected by appropriately increasing the thickness of the sealant but the overall thickness is significantly less than the thickness of the traditional structure outer shell + sealant. Therefore, under the premise of ensuring that the volume of the capacitor core remains unchanged, the structure itself is improved. The volume of surface-mount film capacitors is significantly reduced, the specific capacity is significantly improved, and at the same time, it can ensure that the product has sufficient strength and excellent insulation, flame retardancy, and vibration resistance, meeting the application requirements of higher requirements for miniaturization, lightweight and high specific capacity; at the same time, because the outer shell is removed, and the associated structure between the capacitor core, sheet electrodes, annular reinforcement plates, and welding metal sheets can form a positioning connection relationship, only a reasonable potting shell needs to be designed during potting, and no additional positioning tooling is required, which makes the operation simpler and avoids the problem of increasing the volume due to the need to reserve an installation position for the positioning tooling, further ensuring the characteristics of small size and high specific capacity of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is one of the three-dimensional views of the high specific capacity caseless surface-mount film capacitor of the present invention after assembly, in which the top of the product can be seen;

[0019] Figure 2 This is the second three-dimensional diagram of the high specific capacity caseless surface-mount film capacitor of the present invention after assembly, in which the bottom of the product can be seen;

[0020] Figure 3 This is a three-dimensional exploded view of the high specific capacity caseless surface-mount film capacitor of the present invention before assembly and after the sealant is removed. Figure 1 Consistency;

[0021] Figure 4 This is a three-dimensional diagram of the high specific capacity caseless surface mount film capacitor of the present invention after assembly and removal of the sealant. Figure 1 Consistency;

[0022] Figure 5 It is a front view of the caseless surface-mount film capacitor with high specific capacity according to the present invention after being assembled and the sealant is removed;

[0023] Figure 6 yes Figure 5 AA section view in;

[0024] Figure 7 This is a three-dimensional diagram of the potting mold of the caseless surface-mount film capacitor with high specific capacity according to the present invention before assembly;

[0025] Figure 8 This is a three-dimensional diagram of the potting mold of the high specific capacity surface-mount film capacitor of the present invention before assembly during use. Figure 7 same;

[0026] Fig. 9 1 is a three-dimensional diagram of the upper shell of the potting mold of the caseless surface-mount film capacitor with high specific capacity according to the present invention, and the viewing angle in the figure is Figure 7 and Figure 8 different;

[0027] Fig.10 This is a half-section stereogram of the potting mold of the high specific capacity shellless surface-mount film capacitor of the present invention after being assembled during use. Figure 7 and Figure 8 same;

[0028] Fig.11 This is a three-dimensional diagram of the potting mold of the high specific capacity shellless surface-mount film capacitor of the present invention after being assembled during use. Fig. 9 same.

[0029] Among them, 1-sheet electrode, 2-sealant, 3-welding metal sheet, 4-metal plate end plate, 5-end plate thinning section, 6-metal sheet sink groove, 7-welding groove, 8-core metal plate, 9-sandwich space, 10-reinforcement plate through hole, 11-capacitor core, 12-reinforcement plate sink groove, 13-annular reinforcement plate, 14-first potting through hole, 15-second potting through hole, 16-upper shell, 17-upper wedge-shaped groove, 18-connecting through hole, 19-lower wedge-shaped groove, 20-lower shell, 21-annular sink groove, 22-connecting bolt, 23-lower shell inner cavity, 24-annular boss, 25-glue injection through hole, 26-positioning groove, 27-connecting screw hole, 28-positioning boss, 29-upper shell inner cavity. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings:

[0031] like Figure 1-Figure 6 As shown, the shellless surface-mount film capacitor with high specific capacity described in the present invention includes a capacitor core 11, a sheet electrode 1, a sealant 2, an insulating annular reinforcement plate 13 and a welding metal sheet 3, core metal plates 8 are respectively provided at both ends of the capacitor core 11, two sheet electrodes 1 are respectively connected to the two core metal plates 8, the sealant 2 is coated on the outside of the capacitor core 11, the annular reinforcement plate 13 is placed outside the capacitor core 11, the inner walls at both ends of the annular reinforcement plate 13 are in close contact with the outer walls of the core metal plates 8 at both ends of the capacitor core 11, the inner walls on the opposite sides of the annular reinforcement plate 13 are in close contact with the outer walls on the opposite sides of the capacitor core 11, the two ends of the annular reinforcement plate 13 are respectively provided with reinforcement plate through holes 10, two welding metal sheets 3 are respectively located on the outside of the two ends of the annular reinforcement plate 13, the welding metal sheets 3 are welded and connected to the corresponding core metal plates 8 and the connection parts are located in the corresponding reinforcement plate through holes 10, the welding metal sheets 3 are integrally formed or welded with the sheet electrode 1, and the sealant 2 is coated on the outside of the annular reinforcement plate 13.

[0032] like Figure 1-Figure 6 As shown, the present invention also discloses the following more optimized specific structures:

[0033] In order to achieve a more compact structure and reduce the volume while ensuring strength, the middle section of the welding metal sheet 3 is recessed toward the direction close to the corresponding core metal plate 8 and is placed in the corresponding reinforcing plate through hole 10, and a metal sheet sink groove 6 is formed on the outer wall of the middle section of the welding metal sheet 3. One end of the "L"-shaped sheet electrode 1 is located in the corresponding metal sheet sink groove 6. The two ends of the welding metal sheet 3 are bent toward the direction close to the core metal plate 8 on the opposite side to form a metal plate end plate 4. The metal plate end plate 4 is in contact with the corresponding outer walls on the opposite sides of the annular reinforcing plate 13. A plurality of spaced welding grooves 7 are provided near the edge of one side of the middle section of the welding metal sheet 3, and solder (not shown in the figure) for welding to the corresponding core metal plate 8 is provided in the welding groove 7.

[0034] In order to further achieve a more compact structure while ensuring strength, the outer wall of the annular reinforcement plate 13 corresponding to the metal plate end plate 4 in contact with each other is thinned to form a reinforcement plate groove 12, and the inner wall of the metal plate end plate 4 close to the suspended end is thinned to form an end plate thinning section 5. The end plate thinning section 5 is placed in the corresponding reinforcement plate groove 12 so that the outer wall surface of the metal plate end plate 4 is flush with the outer wall surfaces on the opposite sides corresponding to the annular reinforcement plate 13, and the sealant 2 is coated on the outside of the welding metal sheet 3 but does not coat the outer wall surface of the sheet electrode 1.

[0035] In order to better connect the sealant 2 and the sheet electrode 1 into a whole to improve the sealing effect and the outer packaging strength and avoid cracking between the sealant 2 and the sheet electrode 1, an interlayer space 9 is provided in the sheet electrode 1 and the interlayer space 9 is filled with the sealant 2.

[0036] In order to further improve the strength, the welding metal sheet 3 and the sheet electrode 1 are formed in one piece.

[0037] In order to ensure better connection strength between the sealant 2 and the annular reinforcement plate 13 and the capacitor core 11 and avoid cracking between the sealant 2 and the annular reinforcement plate 13, a plurality of potting through holes are respectively provided on opposite sides of the annular reinforcement plate 13 and the potting through holes are filled with sealant 2.

[0038] In order to further improve the connection strength and stability between the sealant 2 and the annular reinforcement plate 13 and the capacitor core 11, the potting through hole includes a first potting through hole 14 and a second potting through hole 15. The center line of the first potting through hole 14 and the center line of the second potting through hole 15 have an angle of 10°-60° with the opposite side surfaces of the annular reinforcement plate 13, and the center line of the first potting through hole 14 and the center line of the second potting through hole 15 have an angle of 20°-120°. Multiple first potting through holes 14 and multiple second potting through holes 15 are arranged at intervals from each other.

[0039] like Figure 7-Figure 11As shown, the potting mold of the shellless surface-mount film capacitor with high specific capacity described in the present invention includes an upper shell 16, a lower shell 20 and connecting bolts 22, and connecting screw holes 27 are respectively provided near the four corners of the upper shell 16, an upper shell inner cavity 29 with a lower opening is provided in the middle of the upper shell 16, and outwardly protruding positioning bosses 28 are respectively provided in the middle of the cavity walls at both ends of the upper shell inner cavity 29, and connecting through holes 18 are respectively provided near the four corners of the lower shell 20, a lower shell inner cavity 23 with an upper opening is provided in the middle of the lower shell 20, and glue injection through holes 25 are respectively provided at the bottom of the lower shell inner cavity 23 near the four corners, and concave positioning grooves 26 are respectively provided at the bottom of the lower shell inner cavity 23 near the middle of both ends, and four connecting bolts 22 are respectively passed through the four connecting through holes 18 from bottom to top and connected with the four connecting screw holes 27. Preferably, in order to facilitate precise alignment and connection of the upper shell 16 and the lower shell 20, a downwardly protruding annular boss 24 is provided on the upper shell 16 near the upper shell inner cavity 29, and a concave annular groove 21 is provided on the lower shell 20 near the lower shell inner cavity 23, and the annular boss 24 is located in the annular groove 21; in order to facilitate rapid separation of the upper shell 16 and the lower shell 20, an upper wedge-shaped groove 17 with an outer end opening is provided on the lower side of the upper shell 16 near the middle of both ends, and a lower wedge-shaped groove 19 with an outer end opening is provided on the upper side of the lower shell 20 near the middle of both ends, and the two upper wedge-shaped grooves 17 are respectively located above the two lower wedge-shaped grooves 19.

[0040] like Figure 1-Figure 11 As shown, during processing, the capacitor core 11, the sheet electrode 1, the annular reinforcing plate 13 and the welding metal sheet 3 are first assembled together according to the above structure, and the sheet electrode 1 is welded to the core metal plates 8 at both ends of the capacitor core 11. At this time, the other components of the entire capacitor except the sealant 2 are stably or basically stably connected together to form a pre-potting assembly; then the pre-potting assembly is placed as a whole in the lower shell cavity 23 of the lower shell 20, so that the bottoms of the two sheet electrodes 1 are respectively placed in the two positioning grooves 26, and then the upper shell 16 is covered on the pre-potting assembly from top to bottom, so that the two positioning bosses 28 of the upper shell 16 are respectively placed In the two metal sheet sink grooves 6 at both ends of the pre-potting component, the four connecting bolts 22 are then passed through the four connecting through holes 18 from bottom to top and connected with the four connecting screw holes 27, thereby completing the purpose of positioning and installing the pre-potting component through the potting mold; then the potting mold is turned over so that the four injection holes 25 are facing upward, and liquid sealant 2 is injected from two of the injection holes 25, and the other two injection holes 25 are used for exhaust. After filling, wait for the sealant 2 to solidify. After solidification is completed, the potting mold is turned over again, the four connecting bolts 22 are removed, the upper shell 16 is removed, the product is taken out, and the caseless surface-mount film capacitor is obtained after polishing.

[0041] like Figure 1 and Figure 2As shown, when the caseless surface-mount film capacitor with high specific capacity of the present invention is used, the corresponding outer walls of the two sheet electrodes 1 are welded to the printed circuit board, so that reliable small-volume installation can be achieved.

[0042] The present invention adopts the above structure, which can significantly reduce the overall thickness of the capacitor core 11 and the volume of the capacitor. Taking the packaging volume of 20mm×20mm×20mm as an example: the shell wall thickness of the traditional capacitor is 1~1.5mm, the sealant thickness is 0.5~1mm, and the total thickness of the capacitor core on both sides is 1.5~2.5mm; the thickness of the annular reinforcement plate 13 of the capacitor of the present invention is 0.2~0.3mm, the sealant thickness is the thinnest 0.6mm, and the total thickness of the capacitor core 11 on both sides is 0.8~0.9mm, which is significantly thinner than the traditional structure.

[0043] The above embodiments are only preferred embodiments of the present invention and are not limitations of the technical solutions of the present invention. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present invention.

Claims

1. A caseless surface-mount film capacitor with high specific capacity, comprising a capacitor core, a sheet electrode and a sealant, wherein core metal plates are respectively arranged at both ends of the capacitor core, two sheet electrodes are respectively connected to two core metal plates, and the sealant is coated on the outside of the capacitor core, characterized in that: The high specific capacity shellless surface-mount film capacitor also includes an insulating annular reinforcement plate and a welding metal sheet. The annular reinforcement plate is placed outside the capacitor core. The inner walls at both ends of the annular reinforcement plate are in close contact with the outer walls of the core metal plates at both ends of the capacitor core. The inner walls on the opposite sides of the annular reinforcement plate are in close contact with the outer walls on the opposite sides of the capacitor core respectively. Reinforcement plate through holes are respectively provided at both ends of the annular reinforcement plate. The two welding metal sheets are respectively located on the outside of the two ends of the annular reinforcement plate. The welding metal sheet is welded to the corresponding core metal plate and the connection part is located in the corresponding reinforcement plate through hole. The welding metal sheet is integrally formed or welded with the sheet electrode, and the sealant is coated on the outside of the annular reinforcement plate.

2. The high specific capacity caseless surface mount film capacitor according to claim 1, characterized in that: The middle section of the welding metal sheet is recessed toward the direction close to the corresponding core metal plate and is placed in the corresponding through hole of the reinforcing plate, and a metal sheet sink groove is formed on the outer wall of the middle section of the welding metal sheet. One end of the "L"-shaped sheet electrode is located in the corresponding metal sheet sink groove. Both ends of the welding metal sheet are bent toward the direction close to the opposite core metal plate to form metal plate end plates. The metal plate end plates are in contact with and cooperate with the corresponding outer walls on the opposite sides of the annular reinforcing plate. A plurality of spaced welding grooves are provided on the middle section of the welding metal sheet near one side edge, and solder for welding to the corresponding core metal plate is provided in the welding groove.

3. The high specific capacity caseless surface mount film capacitor according to claim 2, characterized in that: The outer wall of the annular reinforcing plate corresponding to the metal plate end plate in contact with each other is thinned to form a reinforcing plate groove, and the inner wall of the metal plate end plate close to the suspended end is thinned to form an end plate thinning section, and the end plate thinning section is placed in the corresponding reinforcing plate groove so that the outer wall surface of the metal plate end plate is flush with the outer wall surfaces on the opposite sides corresponding to the annular reinforcing plate, and the sealant is coated on the outside of the welding metal sheet and does not coat the outer wall surface of the sheet electrode.

4. The high specific capacity caseless surface mount film capacitor according to any one of claims 1 to 3, characterized in that: An interlayer space is provided in the sheet electrode and the interlayer space is filled with the sealant.

5. The high specific capacity caseless surface mount film capacitor according to any one of claims 1 to 3, characterized in that: The welding metal sheet and the sheet-type electrode are integrally formed.

6. The high specific capacity caseless surface mount film capacitor according to any one of claims 1 to 3, characterized in that: A plurality of potting through holes are respectively arranged on opposite sides of the annular reinforcement plate and the potting through holes are filled with the sealant.

7. The high specific capacity caseless surface mount film capacitor according to claim 6, characterized in that: The encapsulation through hole includes a first encapsulation through hole and a second encapsulation through hole, the center line of the first encapsulation through hole and the center line of the second encapsulation through hole both have an angle of 10°-60° with the opposite side surfaces of the annular reinforcement plate, the center line of the first encapsulation through hole and the center line of the second encapsulation through hole have an angle of 20°-120° between them, and a plurality of the first encapsulation through holes and a plurality of the second encapsulation through holes are arranged at intervals from each other.

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