A high current resonant capacitor and a method for preparing an external electrode thereof

Abstract

This invention discloses a high-current resonant capacitor, comprising a core and lead-out terminals. The end face of the core is provided with a metal layer formed by spraying. The lead-out terminals are provided with a central protrusion and a connecting ring. The central protrusion of the lead-out terminals is inserted into the central through-hole of the core. The connecting ring is placed within the corresponding metal layer, and both of its large surfaces are covered by the corresponding metal layer. This invention also discloses a method for preparing the external electrode of the high-current resonant capacitor. This invention achieves a reliable connection between the lead-out terminals and the metal layer by placing the connecting ring within the metal layer on the end face of the core, avoiding the influence of high welding temperatures on the capacitor. This significantly improves the withstand voltage qualification rate, enhances the current withstand capability, strengthens the capacitor's charge and discharge performance, and ensures safety and stability. Simultaneously, the contact area between the connecting ring and the metal layer is larger, resulting in better conductivity and a longer service life. Furthermore, it saves on welding materials and welding processes, reducing costs and improving efficiency.

Description

Technical Field

[0001] This invention relates to a resonant capacitor, and more particularly to a high-current resonant capacitor and a method for preparing its external electrodes, belonging to the field of resonant capacitor manufacturing technology. Background Technology

[0002] Resonant capacitors are widely used in high-current resonant circuits. Their main application is in high-current, high-pulse circuits for coupling, such as in UPS, SMPSs, induction heating power supplies, inverter power supplies, high-frequency heating machines, welding machine power supplies, etc. Their functions and application range are constantly expanding.

[0003] like Figures 1-3 As shown, the basic structure of a traditional resonant capacitor includes a core 2 and lead-out terminals 1. A metal layer 3 is provided on the end face of the core 2. The specific metal used for the metal layer 3 depends on the requirements. The lead-out terminals 1 have a central protrusion 11 and a connecting ring 12. The connecting ring 12 is annular and distributed around the central protrusion 11. The central protrusion 11 is inserted into the central through-hole 21 of the core 2. The connecting ring 12 is welded to the metal layer 3. Note: The resonant capacitor's package is not shown in the figure. Also, generally, one lead-out terminal 1 is installed at each end of the core 2. Due to the symmetrical structure, the metal layer 3 and lead-out terminal 1 at the other end of the core 2 are not shown in the figure. After the lead-out terminal 1 is welded to the metal layer 3, it forms the external electrode of the resonant capacitor. The traditional method for preparing this external electrode is as follows: First, metal particles are sprayed onto the end face of the core 2 to form the metal layer 3. The number of spraying passes and the thickness depend on actual needs. Then, the central protrusion 11 of the lead-out terminal 1 is inserted into the central through hole 21 of the core 2, and the connecting ring 12 is brought into close contact with the metal layer 3. Finally, the connecting ring 12 of the lead-out terminal 1 is welded to the metal layer 3. Specific welding methods generally include two types: one is spot welding, which involves spot welding at multiple locations between the circumferential edge of the connecting ring 12 and the metal layer 3, such as... Figure 3 As shown, multiple welding points 4 are formed along the circumference; another method is to first apply solder paste to the surface of the connecting ring 12 near the metal layer 3, then make the connecting ring 12 and the metal layer 3 into close contact, and then heat the solder paste application position at high frequency to make the connecting ring 12 and the metal layer 3 bond at high temperature, thereby achieving welding between the connecting ring 12 and the metal layer 3.

[0004] The aforementioned traditional resonant capacitors and their welding methods have the following drawbacks: They all require heating of the connecting rings and metal layers at the leads, with temperatures reaching 200℃~300℃ to melt the solder or solder paste for a secure weld. However, the capacitor core's temperature resistance generally does not reach this level. Therefore, the core is easily burned during welding, leading to a decrease in capacitance, an increase in the loss tangent (tgδ), a reduction in voltage withstand capability, and a weakening of current withstand capability. This makes them prone to damage during high-current resonance, significantly reducing their lifespan and negatively impacting their stability and safety during use. Furthermore, traditional structures and welding methods require not only welding equipment but also independent welding procedures, increasing costs and reducing efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a high-current resonant capacitor that does not require welding and a method for preparing its external electrode in order to solve the above-mentioned problems.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] A high-current resonant capacitor includes a core and lead terminals. One or two end faces of the core are provided with a metal layer formed by spraying. The lead terminals are provided with a central protrusion and a connecting ring. The central protrusion of one or two of the lead terminals is inserted into one or both ends of the central through hole of the core. The connecting ring is electrically connected to the corresponding metal layer. The connecting ring is placed in the corresponding metal layer and its two large surfaces are covered by the corresponding metal layer.

[0008] Preferably, in order to make the connection between the connecting ring and the metal layer more stable and reliable, the connecting ring is provided with a plurality of through holes along the circumferential direction, and all the through holes are filled with the corresponding metal layer.

[0009] Preferably, in order to ensure a stable and reliable connection between the connecting ring and the metal layer and to ensure the strength of the connecting ring, the plurality of through holes are evenly distributed along the circumferential direction, and the diameter of the through holes is 2mm and the spacing between the holes is 10mm.

[0010] A method for fabricating the external electrode of a high-current resonant capacitor includes the following steps:

[0011] Step 1: Spray metal particles onto one or both ends of the core to form a metal underlayer;

[0012] Step 2: Drill holes along the circumferential direction on the connecting ring of one or two of the leads to form multiple through holes; the order of this step and step 1 can be interchanged;

[0013] Step 3: Insert the center protrusion of one or two of the lead-out terminals into one or both ends of the center through hole of the core, and make the connecting ring of one or two of the lead-out terminals in close contact with the corresponding metal bottom layer;

[0014] Step 4: Spray metal particles onto the metal underlayer and the connecting ring at one or both ends of the core to form a metal surface layer. The metal surface layer simultaneously fills all the through holes on the corresponding connecting ring. After the metal surface layer covers the corresponding connecting ring, the metal surface layer and the corresponding metal underlayer together form the metal layer, completing the preparation of the external electrode.

[0015] The beneficial effects of this invention are as follows:

[0016] This invention achieves a reliable connection between the lead-out terminal and the metal layer on the end face of the core by placing the connecting ring within the metal layer. This eliminates the need for welding between the connecting ring and the metal layer, avoiding the impact of high welding temperatures on the capacitor and preventing capacitance reduction and increased loss tangent (tgδ) caused by high-temperature burns. The voltage withstand capability is significantly improved, current withstand capability is enhanced, and capacitor charging and discharging performance is strengthened, thus ensuring safety and stability. Simultaneously, the contact area between the connecting ring and the metal layer is larger, resulting in better conductivity and a longer service life. Furthermore, it saves on welding materials and welding processes, reducing costs and increasing efficiency. By using separate metal underlayer and metal toplayer coatings, the connecting ring can be encased within the metal layer during the coating process without significantly increasing time and labor costs, and the amount of metal layer material used is minimal. Therefore, overall, it ensures cost reduction and efficiency improvement. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the main structure of a traditional resonant capacitor before assembly; the encapsulation housing is not shown in the figure.

[0018] Figure 2 This is a schematic diagram of the main structure of a traditional resonant capacitor after assembly; the packaging shell is not shown in the figure.

[0019] Figure 3 This is a top view of the assembled structure of a traditional resonant capacitor. The package housing is not shown in the figure, and the scale is smaller than [missing information]. Figure 1 and Figure 2 ;

[0020] Figure 4 This is a schematic diagram of the main structure of the high-current resonant capacitor after assembly according to the present invention. The packaging shell is not shown in the figure.

[0021] Figure 5 This is a schematic diagram of the main structure of the high-current resonant capacitor core after a metal underlayer has been sprayed onto one end face.

[0022] Figure 6 This is a top view of the structure of the high-current resonant capacitor described in this invention after drilling the lead-out terminals;

[0023] Figure 7 This is a schematic diagram of the main structure of the high-current resonant capacitor described in this invention, showing the central protrusion of one of its leads inserted into one end of the central through hole of the core.

[0024] Figure 8 This is a schematic diagram of the main structure of the high-current resonant capacitor described in this invention, after the central protrusion of one of the leads is inserted into one end of the central through hole of the core and a metal surface layer is sprayed on. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings:

[0026] like Figure 4 As shown, the high-current resonant capacitor of the present invention includes a core 2 and lead-out terminals 5. One or two end faces of the core 2 (one end face is shown in the figure, but in actual applications, two end faces are generally used) are provided with a sprayed metal layer 6. The lead-out terminals 5 are provided with a central protrusion 51 and a connecting ring 52. One or two (one is shown in the figure, but in actual applications, two) central protrusions 51 of the lead-out terminals 5 are inserted into one or both ends (one end is shown in the figure, but in actual applications, two ends are generally used) of the central through hole 21 of the core 2. The connecting ring 52 is electrically connected to the corresponding metal layer 6. The connecting ring 52 is placed in the corresponding metal layer 6 and both of its large surfaces are covered by the corresponding metal layer 6. Figure 4 and Figure 6 As shown, preferably, the connecting ring 52 has multiple through holes 53 along the circumferential direction and all the through holes 53 are filled with the corresponding metal layer 6; the multiple through holes 53 are evenly distributed along the circumferential direction, the diameter of the through holes 53 is 2mm and the spacing between the holes is 10mm.

[0027] like Figures 4-8 As shown, the method for preparing the external electrode of the high-current resonant capacitor of the present invention includes the following steps:

[0028] Step 1: Spray metal particles onto one or both ends of the core 2 to form a metal underlayer 61, such as... Figure 5 As shown;

[0029] Step 2: Drill multiple through holes 53 along the circumferential direction on the connecting ring 52 of one or two leads 5, such as... Figure 6 As shown; the order of this step and step 1 can be interchanged;

[0030] Step 3: Insert the center protrusion 51 of one or two leads 5 into one or both ends of the center through hole 21 of the core 2, and ensure that the connecting ring 52 of one or two leads 5 are in close contact with the corresponding metal substrate 61. Figure 7 As shown;

[0031] Step 4: Spray metal particles onto the metal underlayer 61 and connecting ring piece 52 at one or both ends of the core 2 to form a metal surface layer 62. The metal surface layer 62 simultaneously fills all the through holes 53 on the corresponding connecting ring piece 52. After the metal surface layer 62 covers the corresponding connecting ring piece 52, the metal surface layer 62 and the corresponding metal underlayer 62 together form a metal layer 6, such as... Figure 8 and Figure 4 As shown, the external electrode fabrication is complete.

[0032] Note: The above-mentioned lead-out terminal 5 corresponds to the lead-out terminal 1 in the background art, but the structure of its connecting ring has changed, so although the names are the same, different marking numbers are used; the above-mentioned metal layer 6 corresponds to the metal layer 3 in the background art, but the connection structure between it and the connecting ring has changed, so although the names are the same, different marking numbers are used; the above-mentioned lead-out terminal 1 is exactly the same as the lead-out terminal 1 in the background art, so the same name and marking numbers are used.

[0033] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the technical solutions of the present invention. Any technical solution that can be implemented based on the above embodiments without creative effort should be considered to fall within the scope of protection of the patent of the present invention.

Claims

1. A method for fabricating the external electrode of a high-current resonant capacitor, the high-current resonant capacitor comprising a core and lead-out terminals, wherein one or two end faces of the core are provided with a metal layer formed by spraying, the lead-out terminals are provided with a central protrusion and a connecting ring, one or two central protrusions of the lead-out terminals are inserted into one or both ends of a central through hole of the core, the connecting ring is electrically connected to the corresponding metal layer, the connecting ring is placed within the corresponding metal layer and both of its large surfaces are covered by the corresponding metal layer, the connecting ring is provided with a plurality of through holes along the circumferential direction and all the through holes are filled by the corresponding metal layer, the plurality of through holes are evenly distributed along the circumferential direction, the diameter of the through holes is 2 mm and the spacing between the holes is 10 mm; characterized in that: The method for fabricating the external electrode of the high-current resonant capacitor includes the following steps: Step 1: Spray metal particles onto one or both ends of the core to form a metal underlayer; Step 2: Drill holes along the circumferential direction on the connecting ring of one or two of the leads to form multiple through holes; the order of this step and step 1 can be interchanged; Step 3: Insert the center protrusion of one or two of the lead-out terminals into one or both ends of the center through hole of the core, and make the connecting ring of one or two of the lead-out terminals in close contact with the corresponding metal bottom layer; Step 4: Spray metal particles onto the metal underlayer and the connecting ring at one or both ends of the core to form a metal surface layer. The metal surface layer simultaneously fills all the through holes on the corresponding connecting ring. After the metal surface layer covers the corresponding connecting ring, the metal surface layer and the corresponding metal underlayer together form the metal layer, completing the preparation of the external electrode.

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