High voltage capacitor

Abstract

To provide a high-voltage feed-through capacitor that improves reliability.SOLUTION: An element body 10 is formed with through holes 15, 16 respectively to be open at a first main surface and a second main surface opposing each other. A through-conductor 30 includes a portion 32 located inside the through hole 15 and a portion 33 protruding from the second main surface. A through-conductor 40 includes a portion 42 located inside the through hole 16 and a portion 43 protruding from the second main surface. An insulating case 60 is located to surround the element body 10. An insulating cover 50 is located to surround the portions 33, 43. A resin 70 is located inside the insulating case 50 and coats the element body 10. A resin 80 fills the inside of the insulating cover 60 so as to reach a space between an inner surface 15a and the portion 32 and a space between an inner surface 16a and the portion 42. The resin 80 has an electrical resistivity less than an electrical resistivity of the resin 70.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a high-voltage capacitor. [Background technology]

[0002] A known high-voltage capacitor includes an element body, a through conductor, a grounding metal fitting, an insulating case, an insulating cover, and resin (see, for example, Patent Document 1). The element body has a through hole that opens to a first main surface and a second main surface that face each other. The through conductor has a first portion located within the through hole and a second portion protruding from the second main surface, and is electrically connected to a first electrode that is arranged on the first main surface. The grounding metal fitting is electrically connected to a second electrode that is arranged on the second main surface. The insulating case is arranged to surround the element body. The insulating cover is arranged to surround the second portion. Resin is filled inside the insulating case and inside the insulating cover. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3803258 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of one aspect of the present invention is to provide a high-voltage capacitor with improved reliability. [Means for solving the problem]

[0005] A high-voltage capacitor according to one embodiment comprises an element body, a first electrode, a second electrode, a through conductor, a grounding metal fitting, an insulating case, an insulating cover, a first resin, and a second resin. The element body has a first main surface and a second main surface facing each other. The element body has a through hole opening to the first main surface and the second main surface. The first electrode is disposed on the first main surface. The second electrode is disposed on the second main surface. The through conductor has an outer diameter smaller than the inner diameter of the through hole and is electrically connected to the first electrode. The through conductor has a first portion located within the through hole and a second portion protruding from the second main surface. The grounding metal is electrically connected to the second electrode. The insulating case is disposed to surround the element body. The insulating cover is disposed to surround the second portion. The first resin is filled inside the insulating case so as to cover the element body. The second resin is filled inside the insulating cover so as to reach a space between the inner surface of the element body that defines the through hole and the first portion. The resistivity of the second resin is less than the resistivity of the first resin.

[0006] The present inventors have conducted research into high-voltage capacitors with improved reliability, and as a result have newly discovered the following. The strength of the electric field formed between two conductors, the second electrode and the through conductor, affects the reliability of a high-voltage capacitor. Hereinafter, the strength of the electric field formed between the second electrode and the through conductor may be simply referred to as the "inter-conductor electric field strength." High-voltage capacitors with high inter-conductor electric field strength are prone to dielectric breakdown. Dielectric breakdown occurs, for example, due to discharge along the inner surface of the element body that defines the through hole. Therefore, high-voltage capacitors that employ a configuration that reduces the inter-conductor electric field strength are less likely to suffer from dielectric breakdown. In other words, high-voltage capacitors that employ a configuration that reduces the inter-conductor electric field strength have improved reliability.

[0007] The present inventors conducted research into a configuration for reducing the inter-conductor electric field strength. As a result, the present inventors discovered that the relationship between the resistivity of the first resin and the resistivity of the second resin affects the inter-conductor electric field strength. In other words, a configuration in which the resistivity of the second resin is lower than the resistivity of the first resin reduces the inter-conductor electric field strength. The relationship between the resistivity of the first resin and the resistivity of the second resin has not been considered in the past.

[0008] In the above-described one aspect, the resistivity of the second resin is lower than the resistivity of the first resin, thereby reducing the electric field strength between the conductors and improving reliability. [Effects of the Invention]

[0009] One aspect of the present invention provides a high-voltage capacitor with improved reliability. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an exploded perspective view showing a high-voltage capacitor according to one embodiment. [Figure 2] FIG. 2 is a diagram showing a cross-sectional configuration of the high-voltage capacitor according to this embodiment. [Figure 3] FIG. 3 is a diagram showing the relationship between resistivity and electric field strength. [Figure 4] FIG. 4 is a diagram showing the simulation results of the electric field intensity. [Figure 5] FIG. 5 is a diagram showing the simulation results of the electric field intensity. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same elements or elements having the same functions will be denoted by the same reference numerals, and redundant description will be omitted.

[0012] The configuration of a high-voltage capacitor HC1 according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is an exploded perspective view showing the high-voltage capacitor according to this embodiment. Figure 2 is a diagram showing the cross-sectional configuration of the high-voltage capacitor according to this embodiment. The high-voltage capacitor HC1 includes an element body 10, an electrode 11, an electrode 12, a grounding metal fitting 20, a plurality of through conductors 30, 40, a plurality of electrode connectors 31, 41, a plurality of insulating tubes 37, 47, an insulating case 50, an insulating cover 60, resin 70, and resin 80. In this embodiment, the high-voltage capacitor HC1 includes two through conductors 30, 40, two electrode connectors 31, 41, and two insulating tubes 37, 47.

[0013] The element body 10 has main surfaces 10a and 10b that face each other. In this embodiment, the main surfaces 10a and 10b face each other in the first direction D1. The main surfaces 10a and 10b define both end surfaces of the element body 10 in the first direction D1. The element body 10 has side wall surfaces 10c. The side wall surfaces 10c extend in the first direction D1 so as to connect the main surfaces 10a and 10b to each other. The side wall surfaces 10c define the outer periphery of the element body 10 as viewed in the first direction D1. In this specification, the direction from the main surface 10b toward the main surface 10a is the upward direction, and the main surface 10a is located above the main surface 10b. For example, when the main surface 10a constitutes the first main surface, the main surface 10b constitutes the second main surface.

[0014] The element body 10 is made of, for example, an insulating material. The element body 10 includes, for example, ceramic. The ceramic is, for example, BaTiO 3、 BaZrO 3、 CaTiO 3、 or MgTiO3. The element body 10 may also contain additives to be added to ceramic. The additives include, for example, Si, Mg, Zr, Zn, Y, V, Al, or Mn.

[0015] Electrode 11 is disposed on main surface 10a, and electrode 12 is disposed on main surface 10b. Electrode 11 and electrode 12 face each other in a first direction D1. Element body 10 is located between electrode 11 and electrode 12. Therefore, electrode 11 and electrode 12 indirectly face each other in the first direction D1 with element body 10 located between electrode 11 and electrode 12. Electrode 11 has a pair of conductors 13 and 14. Electrodes 13 and 14 are disposed on main surface 10a. The conductors 13 and 14 are spaced apart from each other on main surface 10a. In this embodiment, conductors 13 and 14 are spaced apart from each other in a second direction D2 intersecting with first direction D1. Each of conductors 13 and 14 faces electrode 12 in the first direction D1. For example, when electrode 11 constitutes a first electrode, electrode 12 constitutes a second electrode.

[0016] The electrodes 11 and 12 include a conductive metal material. The conductive metal material includes, for example, Ag. The electrodes 11 and 12 may include a magnetic material together with the conductive metal material. The magnetic material is, for example, Fe, Co, Ni, Cu, or Sr, or a combination thereof. The electrodes 11 and 12 are formed, for example, by baking a conductive paste applied to the main surface 10a and the main surface 10b. The conductive paste used to form the electrodes 11 and 12 includes the conductive metal material.

[0017] As shown in FIGS. 1 and 2, a plurality of through holes 15, 16 are formed in the element body 10. In this embodiment, two through holes 15, 16 are formed in the element body 10. The element body 10 has an inner surface 15a that defines the through hole 15 and an inner surface 16a that defines the through hole 16. The through hole 15 opens to the main surface 10a and the main surface 10b. The through hole 15 penetrates from the main surface 10a to the main surface 10b. The through hole 16 opens to the main surface 10a and the main surface 10b. The through hole 16 penetrates from the main surface 10a to the main surface 10b. The through holes 15, 16 have a circular shape when viewed from the first direction D1. The through holes 15, 16 may have a shape other than a circular shape.

[0018] A groove 17 is formed in the element body 10. In this embodiment, the groove 17 is formed in the element body 10 so as to be located between the conductor 13 and the conductor 14 when viewed from a direction (first direction D1) perpendicular to the main surface 10a. The conductor 13 and the conductor 14 are separated by the groove 17. No electrode is formed in the groove 17. The element body 10 has wall surfaces 17a that define the groove 17. The groove 17 extends in a third direction D3 that faces the first direction D1 and the second direction D2. The groove 17 reaches both ends of the main surface 10a in the third direction D3. In this embodiment, the first direction D1, the second direction D2, and the third direction D3 are perpendicular to one another.

[0019] The grounding metal 20 is electrically connected to the electrode 12. The grounding metal 20 supports the element body 10. As shown in FIG. 1 , the grounding metal 20 has a protruding portion 21 and a peripheral portion 22. The peripheral portion 22 surrounds the protruding portion 21. The protruding portion 21 protrudes from the peripheral portion 22 toward the element body 10 when viewed from the second direction D2. An opening 23 is formed in the protruding portion 21. The opening 23 penetrates the protruding portion 21 in the first direction D1. In this embodiment, the opening 23 is located in the central region of the protruding portion 21 when viewed from the first direction D1. The grounding metal 20 has a rectangular shape when viewed from the first direction D1. The rectangular shape includes a shape with rounded corners and a shape with rounded corners. The grounding metal 20 may have a shape other than a rectangular shape. The grounding metal 20 includes a conductive metal material, such as Fe, Cu, or a Cu-Zn alloy.

[0020] The element body 10 is arranged so that the electrode 12 is electrically connected to the grounding metal fitting 20. In this embodiment, the element body 10 is supported by the grounding metal fitting 20 so that the protrusion 21 is in contact with the electrode 12. The grounding metal fitting 20 is grounded. The protrusion 21 and the electrode 12 are connected via solder.

[0021] The through conductor 30 is inserted through the through hole 15 and has an outer diameter smaller than the inner diameter of the through hole 15. The through conductor 30 is electrically connected to the electrode 11. The through conductor 30 has a portion 32 located within the through hole 15, a portion 33 protruding from the main surface 10b, a tab portion 34, and a crimp 35. The portion 32 is spaced from the inner surface 15a. In this embodiment, the portions 32 and 33 are integrally formed. The portions 32 and 33 are made of a conductor and have a cylindrical shape when viewed from the first direction D1. The portions 32 and 33 may have a shape other than a cylindrical shape. The tab portion 34 functions as a tab connector. The crimp 35 electrically and physically connects the portions 32 and 33 to the tab portion 34. For example, when the portion 32 constitutes a first portion, the portion 33 constitutes a second portion.

[0022] The through conductor 30 is electrically connected to the conductor 13. In the through conductor 30, the portion 32 and the portion 33 are inserted into the electrode connector 31, the through hole 15, and the opening 23. The electrode connector 31 electrically connects the tab portion 34 and the crimp 35 to the conductor 13. The through conductor 30 is made of, for example, a conductive metal material. The conductive metal material includes, for example, Fe, Cu, or a Cu-Zn alloy.

[0023] The through conductor 40 is inserted through the through hole 16 and has an outer diameter smaller than the inner diameter of the through hole 16. The through conductor 40 is electrically connected to the electrode 11. The through conductor 40 has a portion 42 located within the through hole 16, a portion 43 protruding from the main surface 10b, a tab portion 44, and a crimp 45. The portion 42 is spaced from the inner surface 16a. In this embodiment, the portions 42 and 43 are integrally formed. The portions 42 and 43 are made of a conductor and have a cylindrical shape when viewed from the first direction D1. The portions 42 and 43 may have a shape other than a cylindrical shape. The tab portion 44 functions as a tab connector. The crimp 45 electrically and physically connects the portions 42 and 43 to the tab portion 44. For example, when the portion 42 constitutes a first portion, the portion 43 constitutes a second portion.

[0024] The through conductor 40 is electrically connected to the conductor 14. In the through conductor 40, the portion 42 and the portion 43 are inserted into the electrode connector 41, the through hole 16, and the opening 23. The electrode connector 41 electrically connects the tab portion 44 and the crimping portion 45 to the conductor 14. The through conductor 40 is made of, for example, a conductive metal material. The conductive metal material includes, for example, Fe, Cu, or a Cu-Zn alloy.

[0025] The insulating tube 37 covers the through conductor 30 and has electrical insulation properties. The insulating tube 37 covers the portion 32 and the portion 33. In this embodiment, the insulating tube 37 covers the entire portion 32 and a part of the portion 33. The areas covered by the insulating tube 37, i.e., the entire portion 32 and a part of the portion 33, are inserted into the through hole 15 and the opening 23. The insulating tube 47 covers the through conductor 40 and has electrical insulation properties. The insulating tube 47 covers the portion 42 and the portion 43. In this embodiment, the insulating tube 47 covers the entire portion 42 and part of the portion 43. The areas covered by the insulating tube 47, i.e., the entire portion 42 and part of the portion 43, are inserted into the through hole 16 and the opening 23. Each of the insulating tubes 37 and 47 includes insulating rubber, such as silicone rubber.

[0026] The insulating case 50 has a hollow cylindrical shape. The insulating case 50 may have a shape other than a hollow cylindrical shape. The insulating case 50 houses the element body 10 and the electrodes 11 and 12 inside. In this embodiment, the insulating case 50 houses the entire element body 10, the entire electrodes 11 and 12, a part of the grounding metal 20, and a part of the insulating cover 60 inside. The insulating case 50 is disposed above the insulating cover 60. The insulating case 50 is disposed so as to surround the element body 10. In this embodiment, the insulating case 50 is disposed so as to surround the element body 10, the electrodes 11 and 12, the protrusion 21, the electrode connectors 31 and 41, the portions 32 and 42, the tab portions 34 and 44, and the crimps 35 and 45. The insulating case 50 is physically connected to the grounding metal 20. The insulating case 50 is connected to the grounding metal fitting 20 so that the inner surface of the insulating case 50 located at the lower end contacts the outer surface of the protrusion 21. The lower end surface of the insulating case 50 contacts the upper surface of the peripheral portion 22.

[0027] The insulating cover 60 has a hollow cylindrical shape. The insulating cover 60 may have a shape other than a hollow cylindrical shape. The insulating cover 60 is arranged to surround the portion 33 and the portion 43. In this embodiment, the insulating cover 60 is arranged to surround the portions 33, 43 and the insulating tubes 37, 47. The insulating cover 60 is physically connected to the grounding fitting 20. When viewed from the second direction D2 and the third direction D3, the insulating cover 60 is connected to the grounding fitting 20 so that the surface located at the upper end of the outer surface of the insulating cover 60 contacts the inner surface of the protrusion 21.

[0028] The insulating case 50 and the insulating cover 60 include an insulating material. The insulating material includes, for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), or modified melamine. The insulating material may include an inorganic substance. The inorganic substance includes, for example, glass powder and ceramic powder. The glass powder includes, for example, industrial glass powder. The ceramic powder includes, for example, SiO2 powder, Al2O3 powder, talc (Mg3SiO4O 10 (OH)2), aluminum nitride (AlN), or silicon nitride (Si3N4), or a mixture thereof.

[0029] 2, resin 70 is filled inside the insulating case 50. In this embodiment, resin 70 is filled inside the insulating case 50 so as to cover the element body 10. The resin 70 is disposed between the insulating case 50 and the element body 10, the protrusions 21, the electrode connectors 31 and 41, the tab portions 34 and 44, and the crimps 35 and 45. The resin 70 fills the spaces between the insulating case 50 and the protrusions 21, the element body 10, the electrode connectors 31 and 41, the tab portions 34 and 44, and the crimps 35 and 45. The resin 70 is in contact with the element body 10, the electrodes 11, the grounding metal 20, the electrode connectors 31 and 41, the through conductors 30 and 40, and the insulating case 50. In this embodiment, the resin 70 is in contact with the side wall surface 10c, the wall surface 17a, the electrode 11, the protrusion 21, the electrode connectors 31 and 41, the tab portions 34 and 44, the crimps 35 and 45, and the insulating case 50. The upper edge of the resin 70 reaches a height that buries the crimps 35 and 45, and the lower edge of the resin 70 reaches the protrusion 21. The upper edge of the resin 70 refers to the upper edge of both end edges of the resin 70 in the first direction D1, and the lower edge of the resin 70 refers to the lower edge of both end edges of the resin 70 in the first direction D1.

[0030] The resin 80 fills the inside of the insulating cover 60. In this embodiment, the resin 80 fills the inside of the insulating cover 60 so as to reach the space between the inner surface 15a and the portion 32 and the space between the inner surface 16a and the portion 42. The resin 80 fills the space between the inner surface 15a and the insulating tube 37 and the space between the inner surface 16a and the insulating tube 47. The resin 80 fills the spaces between the insulating cover 60 and the protrusion 21, the inner surfaces 15a and 16a, and the insulating tubes 37 and 47. The resin 80 contacts the element body 10, the electrode 12, the grounding metal 20, the insulating tubes 37 and 47, and the insulating cover 60. In this embodiment, the resin 80 contacts the inner surfaces 15a and 16a, the electrode 12, the protrusion 21, the insulating tubes 37 and 47, and the insulating cover 60. At least the portion of the insulating tube 37 that contacts the resin 80 is located inside the through hole 15. At least the portion of the insulating tube 47 that is in contact with the resin 80 is located inside the through-hole 16. The upper edge of the resin 80 reaches the lower surfaces of the electrode connectors 31, 41, and the lower edge of the resin 80 is located below the lower surface of the peripheral portion 22. The upper edge of the resin 80 refers to the upper edge of both end edges of the resin 80 in the first direction D1, and the lower edge of the resin 80 refers to the lower edge of both end edges of the resin 80 in the first direction D1. For example, if resin 70 constitutes the first resin, resin 80 constitutes the second resin.

[0031] The resin 70 and the resin 80 include an insulating material. The insulating material includes, for example, a thermosetting resin. The thermosetting resin includes, for example, an epoxy resin, a urethane resin, a phenolic resin, or a silicone resin. The resin 70 and the resin 80 may include different insulating materials. In this embodiment, the resin 70 and the resin 80 include an epoxy resin.

[0032] Next, the relationship between the resistivity of each of the resins 70 and 80 and the insulating tubes 37 and 47 and the strength of the electric field formed between the electrode 12 and the through conductors 30 and 40 will be described. The present inventors conducted a simulation to clarify the above relationship. In this simulation, a model was used that was similar to the configuration of high-voltage capacitor HC1, and included element body 10, electrodes 11 and 12, feedthrough conductor 40, insulating tube 47, and resins 70 and 80. In this model, a voltage was applied between electrode 11 and electrode 12, and the strength of the electric field formed between electrode 12 and feedthrough conductor 40 was determined. A DC voltage of 10 kV was applied between electrode 11 and electrode 12.

[0033] The results of the simulation are shown in Figure 3. Figure 3 is a diagram showing the relationship between resistivity and electric field strength. The model used in the above-described simulation does not include the through conductor 30 and the insulating tube 37. However, it will be understood that the results shown in Fig. 3 will be obtained even when a simulation is performed using a model including the through conductor 30 and the insulating tube 37 instead of the through conductor 40 and the insulating tube 47, as long as the shapes and sizes of the through conductor 30 and the insulating tube 37 are equivalent to the shapes and sizes of the through conductor 40 and the insulating tube 47 and the positional relationship between the through conductor 30 and the element body 10 and the electrodes 11, 12 is equivalent to the positional relationship between the through conductor 40 and the element body 10 and the electrodes 11, 12.

[0034] In Example 1, the resistivity ρ1 of resin 70 is 1.0 × 10 13 Ω·m, and the resistivity ρ2 of Resin 80 is 1.0×10 7 Ω·m, and the resistivity ρ3 of the insulating tube 47 is 1.0×10 11 In this case, the strength E of the electric field formed between the electrode 12 and the through conductor 40 is 2.9×10 6 V / m. Hereinafter, the intensity E of the electric field formed between the electrode 12 and the through conductor 40 will be referred to as "electric field intensity E."

[0035] In Example 2, the resistivity ρ1 is 1.0×10 13 Ω m, and the resistivity ρ2 is 1.0×10 9 Ω m, and the resistivity ρ3 is 1.0×10 11Ω·m. In this case, the electric field strength E is 3.1×10 6 V / m. In Example 3, the resistivity ρ1 is 1.0×10 13 Ω m, and the resistivity ρ2 is 1.0×10 11 Ω m, and the resistivity ρ3 is 1.0×10 11 Ω·m. In this case, the electric field strength E is 7.1×10 6 V / m. In Example 4, the resistivity ρ1 is 1.0 × 10 13 Ω m, and the resistivity ρ2 is 1.0×10 13 Ω m, and the resistivity ρ3 is 1.0×10 11 Ω·m. In this case, the electric field strength E is 1.2×10 7 V / m. In Example 5, the resistivity ρ1 is 1.0 × 10 13 Ω m, and the resistivity ρ2 is 1.0×10 15 Ω m, and the resistivity ρ3 is 1.0×10 11 Ω·m. In this case, the electric field strength E is 1.2×10 7 V / m.

[0036] In Example 6, the resistivity ρ1 is 1.0 × 10 13 Ω m, and the resistivity ρ2 is 1.0×10 9 Ω m, and the resistivity ρ3 is 1.0×10 15 Ω·m. In this case, the electric field strength E is 2.8×10 6 V / m. In Example 7, the resistivity ρ1 is 1.0 × 10 13 Ω m, and the resistivity ρ2 is 1.0×10 11 Ω m, and the resistivity ρ3 is 1.0×10 15 Ω·m. In this case, the electric field strength E is 2.3×10 6 V / m.

[0037] In Example 8, the resistivity ρ1 is 1.0 × 10 15 Ω m, and the resistivity ρ2 is 1.0×10 9 Ω m, and the resistivity ρ3 is 1.0×10 15 Ω·m. In this case, the electric field strength E is 2.8×10 6V / m. In Example 9, the resistivity ρ1 is 1.0×10 15 Ω m, and the resistivity ρ2 is 1.0×10 11 Ω m, and the resistivity ρ3 is 1.0×10 15 Ω·m. In this case, the electric field strength E is 2.3×10 6 V / m. In Example 10, the resistivity ρ1 is 1.0 × 10 15 Ω m, and the resistivity ρ2 is 1.0×10 13 Ω m, and the resistivity ρ3 is 1.0×10 15 Ω·m. In this case, the electric field strength E is 2.3×10 6 V / m.

[0038] In Example 11, the resistivity ρ1 is 1.0 × 10 7 Ω m, and the resistivity ρ2 is 1.0×10 13 Ω m, and the resistivity ρ3 is 1.0×10 11 Ω·m. In this case, the electric field strength E is 1.2×10 7 V / m. In Example 12, the resistivity ρ1 is 1.0 × 10 9 Ω m, and the resistivity ρ2 is 1.0×10 13 Ω m, and the resistivity ρ3 is 1.0×10 11 Ω·m. In this case, the electric field strength E is 1.2×10 7 V / m. In Example 13, the resistivity ρ1 is 1.0 × 10 11 Ω m, and the resistivity ρ2 is 1.0×10 13 Ω m, and the resistivity ρ3 is 1.0×10 11 Ω·m. In this case, the electric field strength E is 1.2×10 7 V / m.

[0039] In Example 14, the resistivity ρ1 is 1.0 × 10 13 Ω m, and the resistivity ρ2 is 1.0×10 11 Ω m, and the resistivity ρ3 is 1.0×10 13 Ω·m. In this case, the electric field strength E is 2.4×10 6 V / m. In Example 15, the resistivity ρ1 is 1.0 × 10 13 Ω m, and the resistivity ρ2 is 1.0×10 11 Ω m, and the resistivity ρ3 is 1.0×10 15 Ω·m. In this case, the electric field strength E is 2.3×10 6 V / m.

[0040] In Example 16, the resistivity ρ1 is 1.0 × 10 13 Ω m, and the resistivity ρ2 is 1.0×10 9 Ω m, and the resistivity ρ3 is 1.0×10 9 Ω·m. In this case, the electric field strength E is 9.8×10 6 V / m. In Example 17, the resistivity ρ1 is 1.0 × 10 13 Ω m, and the resistivity ρ2 is 1.0×10 9 Ω m, and the resistivity ρ3 is 1.0×10 13 Ω·m. In this case, the electric field strength E is 2.8×10 6 V / m. In Example 18, the resistivity ρ1 is 1.0 × 10 13 Ω m, and the resistivity ρ2 is 1.0×10 9 Ω m, and the resistivity ρ3 is 1.0×10 15 Ω·m. In this case, the electric field strength E is 2.8×10 6 V / m.

[0041] In Examples 4, 5, and 11 to 13, where the resistivity ρ2 is equal to or greater than the resistivity ρ1, as shown in FIG. 4, the electric field intensity E is 1.0×10 7 V / m or more, and the strength of the electric field formed between the electrode 12 and the through conductor 40 is high. According to the findings of the present inventors, when the electric field strength E is 1.0×10 7 In configurations where the capacitance is greater than or equal to V / m, dielectric breakdown is likely to occur in high-voltage capacitors. In contrast, in Examples 1 to 3, 6 to 10, and 14 to 18, in which the resistivity ρ2 is smaller than the resistivity ρ1, as shown in FIG. 5, the electric field intensity E is 1.0×10 7V / m, and the strength of the electric field formed between the electrode 12 and the through conductor 40 is low. Therefore, it can be understood that a high-voltage capacitor in which the resistivity ρ2 is smaller than the resistivity ρ1 is less likely to suffer from dielectric breakdown. 4 and 5 are diagrams showing the results of a simulation of the electric field strength. In FIG. 4 and FIG. 5, the electric field strength E is 1.0×10 7 As described above, in Examples 1 to 3 and 9 to 13, the electric field strength E was 1.0×10 7 Since the value is less than V / m, the hatched area does not exist in FIG.

[0042] Based on Examples 1 to 3, 6 to 10 and 14 to 18, the following points are understood. Resistivity ρ2 is 1×10 7 Ω m or more 1×10 13 High-voltage capacitors with a dielectric strength of Ω·m or less are less likely to experience dielectric breakdown. A high-voltage capacitor in which the ratio of resistivity ρ2 to resistivity ρ1 is equal to or greater than 0.000001 and equal to or less than 0.01 is less likely to suffer from dielectric breakdown.

[0043] Based on Examples 1 to 3, 6 to 10 and 14 to 18, the following is also understood. A high-voltage capacitor having a resistivity ρ3 equal to or greater than the resistivity ρ2 is less likely to suffer from dielectric breakdown. Resistivity ρ3 is 1×10 9 Ω m or more 1×10 15 High-voltage capacitors with a dielectric strength of Ω·m or less are less likely to experience dielectric breakdown. Dielectric breakdown is unlikely to occur in a high-voltage capacitor in which the ratio of resistivity ρ2 to resistivity ρ3 is 0.000001 or more and 1 or less. Dielectric breakdown is even less likely to occur in a high-voltage capacitor in which the ratio of resistivity ρ2 to resistivity ρ3 is 0.000001 or more and 0.01 or less.

[0044] For the above reasons, the high-voltage capacitor HC1 employs a configuration in which the resistivity of the resin 80 is smaller than the resistivity of the resin 70. Therefore, the high-voltage capacitor HC1 reduces the strength of the electric field formed between the electrode 12 and the through conductor 40 and the strength of the electric field formed between the electrode 12 and the through conductor 30, thereby improving reliability.

[0045] In the high-voltage capacitor HC1, the resistivity of resin 80 is 1 x 10 7 Ω m or more 1×10 13 A configuration with a resistance of Ω·m or less is adopted. Therefore, the high-voltage capacitor HC1 easily and reliably achieves a configuration that is less susceptible to dielectric breakdown.

[0046] The high-voltage capacitor HC1 employs a configuration in which the ratio of the resistivity of the resin 80 to the resistivity of the resin 70 is equal to or greater than 0.000001 and is equal to or less than 0.01. Therefore, the high-voltage capacitor HC1 easily and reliably achieves a configuration that is less susceptible to dielectric breakdown.

[0047] In the high-voltage capacitor HC1, a configuration is adopted in which the resistivity of each of the insulating tubes 37 and 47 is equal to or higher than the resistivity of the resin 80. Therefore, the high-voltage capacitor HC1 easily and reliably achieves a configuration that is less susceptible to dielectric breakdown.

[0048] The resistivity of the insulating tube 37 and the resistivity of the insulating tube 47 may be equivalent. "Equivalent" does not necessarily mean that the values ​​are the same. The values ​​may be considered equivalent even if they include slight differences within a preset range, manufacturing errors, or measurement errors. The resistivity of the insulating tube 37 and the resistivity of the insulating tube 47 may be different from each other.

[0049] In the high-voltage capacitor HC1, the resistivity of each of the insulating tubes 37 and 47 is 1×10 9 Ω m or more 1×10 15 A configuration with a resistance of Ω·m or less is adopted. Therefore, the high-voltage capacitor HC1 easily and reliably achieves a configuration that is less susceptible to dielectric breakdown.

[0050] In the high-voltage capacitor HC1, a configuration is adopted in which the ratio of the resistivity of the resin 80 to the resistivity of each of the insulating tubes 37, 47 is 0.000001 or more and 1 or less. Therefore, the high-voltage capacitor HC1 easily and reliably achieves a configuration that is less susceptible to dielectric breakdown. The high-voltage capacitor HC1 may be configured such that the ratio of the resistivity of the resin 80 to the resistivity of each of the insulating tubes 37 and 47 is 0.000001 or more and 0.01 or less. Therefore, the high-voltage capacitor HC1, which employs a configuration in which the ratio of the resistivity of the resin 80 to the resistivity of each of the insulating tubes 37, 47 is 0.000001 or more and 0.01 or less, easily and reliably realizes a configuration in which dielectric breakdown is even less likely to occur.

[0051] The high-voltage capacitor HC1 employs a configuration in which the resin 70 and the resin 80 contain epoxy resin. Therefore, the high-voltage capacitor HC1 easily realizes the resins 70 and 80 having different resistivities.

[0052] Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0053] Although the high-voltage capacitor HC1 has two through conductors 30, 40, the high-voltage capacitor HC1 may have three or more through conductors. The high-voltage capacitor HC1 may have either one of the two through conductors 30, 40, i.e., a single through conductor. The number of through holes formed in the element body 10, the number of insulating tubes, the number of conductors included in the electrodes 11, and the number of electrode connectors may correspond to the number of through conductors. [Explanation of symbols]

[0054] 10...element body, 10a, 10b...main surfaces, 11, 12...electrodes, 15, 16...through holes, 15a, 16a...inner surfaces, 20...grounding fitting, 30, 40...through conductors, 32, 33, 42, 43...through conductor portions, 37, 47...insulating tubes, 50...insulating case, 60...insulating cover, 70, 80...resin, HC1...high-voltage through-type capacitor.

Claims

1. an element body having a first main surface and a second main surface opposed to each other, and having through holes opening to the first main surface and the second main surface; a first electrode disposed on the first principal surface; a second electrode disposed on the second major surface; a through conductor having an outer diameter smaller than an inner diameter of the through hole, electrically connected to the first electrode, and having a first portion located within the through hole and a second portion protruding from the second main surface; a grounding metal piece electrically connected to the second electrode; an insulating case disposed to surround the element body; an insulating cover disposed to surround the second portion; a first resin filled inside the insulating case so as to cover the element body; a second resin filled inside the insulating cover so as to reach a space between the first portion and an inner surface of the element body that defines the through hole, the first resin and the second resin include an epoxy resin; The high-voltage capacitor, wherein the resistivity of the second resin is lower than the resistivity of the first resin and is equal to or greater than 1×10 7 Ω·m and equal to or less than 1×10 9 Ω·m.

2. further comprising an insulating tube covering the first portion; the second resin is filled inside the insulating cover so as to reach a space between the inner surface and the insulating tube, The high-voltage capacitor according to claim 1 , wherein the resistivity of the insulating tube is equal to or greater than the resistivity of the second resin.

3. The resistivity of the insulating tube is 1×10 ９ Ω・m or more 1×10 １５ The high-voltage capacitor according to claim 2, wherein the resistance is Ω·m or less.

4. 4. The high-voltage capacitor according to claim 2, wherein a ratio of a resistivity of the second resin to a resistivity of the insulating tube is 0.000001 or more and 1 or less.

5. 5. The high-voltage capacitor according to claim 4, wherein a ratio of the resistivity of the second resin to the resistivity of the insulating tube is 0.000001 or more and 0.01 or less.

6. 6. The high-voltage capacitor according to claim 1, wherein a ratio of the resistivity of the second resin to the resistivity of the first resin is 0.000001 or more and 0.01 or less.

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