A high-voltage multilayer ceramic capacitor for space use

Abstract

The utility model discloses a kind of medium-high voltage multilayer porcelain dielectric capacitors for spaceflight, it relates to capacitor structure field, comprising: inner electrode piece, including multiple misposition stacked inner electrode diaphragm;End electrode piece, including positive electrode and negative electrode, the positive electrode is arranged at one end of the inner electrode piece, the negative electrode is arranged at the other end of the inner electrode piece;Shielding electrode piece, including top shielding electrode diaphragm and / or bottom shielding electrode diaphragm, the top shielding electrode diaphragm is stacked at the outside of top end the inner electrode diaphragm, the bottom shielding electrode diaphragm is stacked at the outside of bottom end the inner electrode diaphragm.The utility model is by setting shielding electrode piece, and limiting shielding electrode piece specific setting position and structure, to reach while guaranteeing the original performance of multilayer porcelain dielectric capacitor, improve vacuum surface flashover hazard, adapt to the purpose of spaceflight field.

Description

Technical Field

[0001] This utility model relates to the field of capacitor structure, specifically to a medium-high voltage multilayer ceramic capacitor for aerospace applications. Background Technology

[0002] Multilayer ceramic capacitors consist of multiple alternating layers of ceramic dielectric and metal electrode layers, sintered at high temperatures to form a ceramic body, with metal electrode layers sealed at both ends for connection to external circuits. Ceramic dielectrics typically have a high dielectric constant, enabling large capacitance within a small volume. Modern electronic devices demand miniaturized, high-performance, high-capacity, and high-voltage ceramic capacitors to meet the energy storage and filtering requirements of circuits within limited space.

[0003] Driven by the future development needs of the aerospace field, ceramic capacitors serve as a dual driver for the upgrading of key electronic components and the expansion of application scenarios. At the same time, they also need to address technical bottlenecks and reliability challenges. For example, under vacuum and certain operating voltage conditions, vacuum surface flashover can occur on the surface of ceramic capacitors, which can lead to the breakdown and failure of electronic components.

[0004] The principle of vacuum surface flashover is as follows: Vacuum surface flashover refers to the gas discharge phenomenon that occurs on the surface of a ceramic insulator when the electric field strength exceeds a certain threshold in a vacuum environment. Increased electric field distortion leads to charge accumulation, eventually causing the metal electrode to release initial electrons into the vacuum under relatively low applied voltage. These initial electrons, after entering the vacuum, bombard the ceramic surface under the influence of the electric field, exciting secondary electrons that accumulate until an electron avalanche forms on the ceramic surface. At a certain stage of the electron avalanche, gas molecules adsorbed on the insulating medium surface desorb, and even the shallow surface layer of the dielectric material vaporizes. Under the influence of a strong electric field, this further ionizes and breaks down, ultimately resulting in surface flashover discharge breakdown at a voltage lower than the internal breakdown voltage (see "A Review of Global Models and Numerical Simulations of Vacuum Surface Flashover" by the State Key Laboratory of Xi'an Jiaotong University). Figure 1 As shown, for multilayer ceramic capacitors, the different relative permittivity of the electrodes, ceramic dielectric, and vacuum leads to electric field distortion at their junctions. These distortions result in an electric field strength at these junctions that is significantly higher than at other locations on the capacitor surface. The substantial increase in electric field strength caused by the distortion at the cathode triple junction (cathode-ceramic dielectric-vacuum) is the core reason for induced vacuum surface flashover.

[0005] Hazards of vacuum surface flashover: (1) Decreased insulation performance: Vacuum surface flashover will cause conductive channels to form on the surface of the insulating medium, resulting in a significant reduction in its insulation performance. This may cause short circuits between electronic components, affecting the normal operation of the circuit, and even causing equipment failure. (2) Component damage: The high temperature and strong current generated during the flashover process will cause direct thermal damage and electrical stress impact on electrical components. Vacuum surface flashover may cause electrode erosion of capacitors, melting of inductor coils, and breakdown of PN junctions of semiconductor devices, thus causing permanent failure of components. (3) Changes in performance parameters: After a flashover occurs, electronic components may not be damaged immediately, but their performance parameters may change. For example, the resistance value of resistors may change due to the heat generated by the flashover, and the amplification factor and threshold voltage of transistors may also be affected, thereby affecting the performance and stability of the entire electronic system.

[0006] While existing technologies have addressed the aforementioned issues, they still have many shortcomings, as detailed below:

[0007] (1) Existing technology 1: Optimization of electrode materials and structure

[0008] Choosing electrode materials with high electrical conductivity and good chemical stability, and employing comb-like or interdigitated electrode structures to increase the contact area between the electrode and the dielectric, results in a more uniform electric field distribution and reduces local electric field intensity. The disadvantages of this technology include increased complexity and cost in electrode manufacturing, and potentially increased capacitor size.

[0009] (2) Existing technology 2: Adjusting the parameters of the dielectric layer

[0010] Optimizing parameters such as the thickness of the ceramic dielectric and the protective layer, as well as the dielectric constant, results in a more rational distribution of the electric field within the dielectric. The disadvantages of this technique include the potential impact on the core electrical performance of the capacitor, and the need for extensive experimentation and calculations to find the optimal parameter combination.

[0011] (3) Existing technology 3: Surface treatment

[0012] The distribution of surface charge is adjusted by coating the ceramic body with an insulating coating. Disadvantages of this technology include potential problems with the adhesion between the coating and the ceramic surface, which may lead to coating peeling under prolonged use or in harsh environments such as high temperature and high humidity. Furthermore, the coating may affect the capacitor's heat dissipation performance.

[0013] In view of the above, this application is hereby submitted. Utility Model Content

[0014] The purpose of this invention is to provide a medium- and high-voltage multilayer ceramic capacitor for aerospace applications. By setting shielding electrodes and limiting the specific location and structure of the shielding electrodes, the invention solves the problem in the prior art of improving the vacuum surface flashover hazard while ensuring the original performance of the multilayer ceramic capacitor.

[0015] This utility model embodiment is achieved through the following technical solution: This utility model embodiment provides a medium-high voltage multilayer ceramic capacitor for aerospace applications, comprising:

[0016] The internal electrode component includes multiple internal electrode films that are staggered and stacked.

[0017] The terminal electrode includes a positive electrode and a negative electrode, with the positive electrode disposed at one end of the inner electrode and the negative electrode disposed at the other end of the inner electrode.

[0018] The shielding electrode includes a top shielding electrode diaphragm and / or a bottom shielding electrode diaphragm, wherein the top shielding electrode diaphragm is stacked on the outside of the top inner electrode diaphragm, and the bottom shielding electrode diaphragm is stacked on the outside of the bottom inner electrode diaphragm.

[0019] Optionally, a single inner electrode diaphragm includes an inner electrode pattern, and both the top shielding electrode diaphragm and the bottom shielding electrode diaphragm include a first shielding electrode pattern and a second shielding electrode pattern.

[0020] The first shielding electrode pattern is connected to the positive electrode, and the second shielding electrode pattern is connected to the negative electrode. There is a gap between the first shielding electrode pattern and the second shielding electrode pattern, and the gap width is d1.

[0021] The first and second shielding electrode patterns are arranged symmetrically along the left and right axes.

[0022] Optionally, the margin distance of the inner electrode pattern is d2, where d2 > d1.

[0023] Optionally, the inner electrode pattern is rectangular, and both the first shielding electrode pattern and the second shielding electrode pattern are rectangular.

[0024] Optionally, the corners of the inner electrode pattern's edge are rounded, and the corners of the ends where the first shielding electrode pattern and the second shielding electrode pattern face each other are also rounded.

[0025] Optionally, the rounded corner radius on the inner electrode pattern is 0.5mm≤R≤2mm, and the rounded corner radius on the first shielding electrode pattern and the second shielding electrode pattern is 0.5mm≤R≤2mm.

[0026] Optionally, it also includes a first side shielding electrode, which includes a first side shielding pattern and a second side shielding pattern disposed on each inner electrode diaphragm. The first side shielding pattern and the second side shielding pattern are symmetrically disposed at both ends of a single inner electrode diaphragm. The first side shielding pattern and the second side shielding pattern are on the same horizontal straight line and have a distance d1 between them.

[0027] Both the first and second side shielding patterns are located above the inner electrode pattern.

[0028] Optionally, it also includes a second side shielding electrode, which includes a third side shielding pattern and a fourth side shielding pattern disposed on each inner electrode diaphragm. The third side shielding pattern and the fourth side shielding pattern are symmetrically disposed at both ends of a single inner electrode diaphragm. The third side shielding pattern and the fourth side shielding pattern are on the same horizontal straight line and have a distance d1 between them.

[0029] Both the third-side shielding pattern and the fourth-side shielding pattern are located below the inner electrode pattern.

[0030] Optionally, the first and second side shielding patterns are arranged in a vertically symmetrical manner with the third and fourth side shielding patterns.

[0031] Optionally, the first shielding electrode pattern or the second shielding electrode pattern can cover the inner electrode pattern in the direction of width d3.

[0032] Compared with the prior art, the embodiments of this utility model have the following advantages and beneficial effects:

[0033] 1. This utility model embodiment optimizes the electric field of the capacitor by changing the top and bottom shielding protection electrodes, thereby reducing the electric field strength and increasing the voltage threshold for vacuum surface flashover.

[0034] 2. This utility model embodiment provides shielding protection electrodes on the side of the capacitor and shielding protection electrodes with the same and opposite potentials on both sides of the effective electrode area. The distance between the two opposite electrodes is increased. By increasing the side shielding electrodes, a Faraday cage-like structure is formed, which changes and optimizes the electric field of the capacitor. The electric field lines are more uniformly distributed, the electric field strength is reduced, and thus the voltage threshold for vacuum surface flashover is increased.

[0035] 3. By setting the electrode pattern to a rounded corner shape, this utility model can increase the radius of curvature of the electrode edge, reduce the electric field distortion caused by abrupt changes in electrode shape, make the electric field lines more uniformly distributed, thereby effectively alleviating the edge effect, improving the electric field distribution, and thus reducing the risk of vacuum surface flashover.

[0036] In general, the embodiments of this utility model provide a medium-high voltage multilayer ceramic capacitor for aerospace applications. By setting shielding electrodes and limiting the specific placement and structure of the shielding electrodes, the original performance of the multilayer ceramic capacitor is guaranteed while mitigating the risk of vacuum surface flashover, thus adapting it to the aerospace field. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the principle of vacuum surface flashover.

[0039] Figure 2 This is a vector diagram of disordered electric fields in existing technologies;

[0040] Figure 3 This is an ordered electric field vector diagram in the embodiments of this utility model;

[0041] Figure 4 This is a structural diagram of a membrane in the prior art;

[0042] Figure 5 This is a diagram showing the disassembled structure of the diaphragm in an embodiment of the present invention;

[0043] Figure 6 This is a structural diagram of a single internal electrode diaphragm in an embodiment of this utility model;

[0044] Figure 7 This is a diagram of a capacitor assembly in the prior art;

[0045] Figure 8 This is an assembly diagram of the capacitor in an embodiment of the present invention.

[0046] The attached diagram shows the markings and corresponding component names:

[0047] 100 - Internal electrode component, 110 - Internal electrode diaphragm, 111 - Internal electrode pattern;

[0048] 200 - End electrode, 201 - Positive electrode, 202 - Negative electrode;

[0049] 300 - Shielding electrode, 310 - Top shielding electrode film, 311 - First shielding electrode pattern, 312 - Second shielding electrode pattern, 320 - Bottom shielding electrode film, 330 - First side shielding electrode, 331 - First side shielding pattern, 332 - Second side shielding pattern, 340 - Second side shielding electrode, 341 - Third side shielding pattern, 342 - Fourth side shielding pattern. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can typically be arranged and designed in various different configurations.

[0051] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0052] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0053] In the description of this utility model, it should be noted that the terms "first", "second", "third", etc. are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0054] Example

[0055] Conventional multilayer ceramic capacitors typically employ a "BB" structure internally, operating at high vacuum levels (≤10). -3 In a vacuum environment (Pa), the junction between the edge of the metallized layer and the ceramic surface forms a "cathode triple junction." Due to the significant difference in dielectric constants among the three materials, this region experiences enhanced electric field distortion under applied voltage, leading to surface charge accumulation and a chaotic electric field distribution (black arrows indicate the direction of the electric field lines). Figure 2 and Figure 7As shown. The shielding protection electrode is an additional unidirectional inner electrode (connected to only one end electrode) added to the upper and lower protective sheets and the side area of ​​the electrode pattern. It lies between the outermost inner electrode and the end metallization layer, and is connected to one end electrode, carrying the same charge. This shielding layer acts as a barrier, preventing the inner electrode from influencing the electric field at the surface cathode triple junction. Adding this shielding protection layer optimizes the electric field distribution of the capacitor, making the electric field distribution more orderly, and reduces the field strength at the capacitor's "cathode triple junction" (e.g., ...). Figure 3 and Figure 8 As shown (the black arrow indicates the direction of the electric field lines), this increases the voltage threshold for inducing the initial electrons in field emission, thereby preventing vacuum surface flashover breakdown under a certain voltage.

[0056] Therefore, this utility model embodiment provides a medium-high voltage multilayer ceramic capacitor for aerospace applications, combined with... Figure 5 and Figure 6 As shown, the device includes an inner electrode 100, an end electrode 200, and a shielding electrode 300. The inner electrode 100 includes a plurality of staggered stacked inner electrode films 110. The end electrode 200 includes a positive electrode 201 and a negative electrode 202, with the positive electrode 201 disposed at one end of the inner electrode 100 and the negative electrode 202 disposed at the other end of the inner electrode 100. The shielding electrode 300 includes a top shielding electrode film 310 and / or a bottom shielding electrode film 320, with the top shielding electrode film 310 stacked on the outside of the top inner electrode film 110 and the bottom shielding electrode film 320 stacked on the outside of the bottom inner electrode film 110.

[0057] Traditional multilayer ceramic capacitors are fabricated by stacking electrode patterns of the same shape in a staggered manner (e.g.) Figure 4 As shown), under vacuum conditions, the electric field distortion at the "cathode triple junction" is large, and the electric field strength at the top and bottom of the capacitor is high. This embodiment of the invention designs top and bottom shielding protection electrodes (such as...). Figure 5 As shown, by changing the electric field of the optimized capacitor, the electric field strength is reduced, thereby increasing the voltage threshold for vacuum surface flashover.

[0058] Further, each inner electrode diaphragm 110 includes an inner electrode pattern 111, and both the top shielding electrode diaphragm 310 and the bottom shielding electrode diaphragm 320 include a first shielding electrode pattern 330 311 and a second shielding electrode pattern 312. The first shielding electrode pattern 330 311 is connected to the positive electrode 201, and the second shielding electrode pattern 312 is connected to the negative electrode 202. There is a gap between the first shielding electrode pattern 330 311 and the second shielding electrode pattern 312, and the gap width is d1. The first shielding electrode pattern 330 311 and the second shielding electrode pattern 312 are arranged symmetrically along the left and right axes. Preferably, the margin distance of the inner electrode pattern 111 is d2, where d2 > d1. More preferably, the first shielding electrode pattern 330 311 or the second shielding electrode pattern 312 can cover the inner electrode pattern 111 in the direction of width d3.

[0059] It should be noted that in this embodiment of the present invention, the inner electrode pattern 111 is rectangular, and both the first shielding electrode pattern 330 pattern 311 and the second shielding electrode pattern 312 are rectangular. Of course, in other embodiments, the inner electrode pattern 111, the first shielding electrode pattern 330 pattern 311, and the second shielding electrode pattern 312 can be other shapes, which are not limited here.

[0060] Because the internal electrode pattern of traditional multilayer ceramic capacitors is square (e.g.) Figure 4 As shown), the electric field strength is high at the electrode edge, making it prone to electric field concentration. The electrode pattern designed in this embodiment has rounded corners (as shown). Figure 5 and Figure 6 As shown in the figure, based on processing feasibility and simulation theory analysis, in this embodiment of the invention, the rounded corner radius of the electrode pattern is 0.5mm≤R≤2mm, including the rounded corner radius on the inner electrode pattern 111, and the rounded corner radius on the first shielding electrode pattern 311 and the second shielding electrode pattern 312. This structure can increase the radius of curvature of the electrode edge, reduce the electric field distortion caused by abrupt changes in electrode shape, make the electric field line distribution more uniform, thereby effectively alleviating the edge effect, improving the electric field distribution, and thus reducing the risk of vacuum surface flashover.

[0061] As a preferred embodiment of this utility model, refer to Figure 6As shown, it also includes a first side shielding electrode, which includes a first side shielding pattern 331 and a second side shielding pattern 332 disposed on each inner electrode diaphragm 110. The first side shielding pattern 331 and the second side shielding pattern 332 are symmetrically disposed at both ends of a single inner electrode diaphragm 110. The first side shielding pattern 331 and the second side shielding pattern 332 are on the same horizontal straight line and have a distance d1 between them. The first side shielding pattern 331 and the second side shielding pattern 332 are both located above the inner electrode pattern 111.

[0062] More preferably, it also includes a second side shielding electrode 340, which includes a third side shielding pattern 341 and a fourth side shielding pattern 342 disposed on each inner electrode diaphragm 110. The third side shielding pattern 341 and the fourth side shielding pattern 342 are symmetrically disposed at both ends of a single inner electrode diaphragm 110, and are on the same horizontal line with a distance d1 between them. Both the third side shielding pattern 341 and the fourth side shielding pattern 342 are located below the inner electrode pattern 111. Further, the first side shielding pattern 331 and the second side shielding pattern 332 are arranged vertically symmetrically with respect to the third side shielding pattern 341 and the fourth side shielding pattern 342.

[0063] Traditional multilayer ceramic capacitors contain only a single, staggered stacked electrode pattern. The electrode pattern is connected to one end electrode, and there is no shielding layer on the side of the electrode pattern (e.g., Figure 4 As shown), under vacuum conditions, the electric field distortion at the "cathode triple junction" is large, and the electric field strength on the side of the capacitor is high. The side shielding protection electrode designed in this embodiment (such as...) Figure 6 As shown, shielding electrodes with the same and opposite potentials are set on both sides of the effective electrode region, with a distance between the two opposing electrodes. By adding side shielding electrodes, a Faraday cage-like structure is formed, which changes and optimizes the capacitor's electric field, making the electric field lines more uniform, reducing the electric field strength, and thus increasing the voltage threshold for vacuum surface flashover.

[0064] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model. It should be noted that the structures or components illustrated in the accompanying drawings are not necessarily drawn to scale, and descriptions of well-known components, processing techniques, and processes have been omitted to avoid unnecessarily limiting the scope of this utility model.

Claims

1. A medium-high voltage multilayer ceramic capacitor for aerospace applications, characterized in that, include: The internal electrode component (100) includes a plurality of internal electrode films (110) arranged in a staggered stack. The end electrode (200) includes a positive electrode (201) and a negative electrode (202), wherein the positive electrode (201) is disposed at one end of the inner electrode (100) and the negative electrode (202) is disposed at the other end of the inner electrode (100); The shielding electrode (300) includes a top shielding electrode film (310) and / or a bottom shielding electrode film (320), the top shielding electrode film (310) being stacked on the outside of the top inner electrode film (110), and the bottom shielding electrode film (320) being stacked on the outside of the bottom inner electrode film (110).

2. The aerospace medium-high voltage multilayer ceramic capacitor according to claim 1, characterized in that, Each of the inner electrode films (110) includes an inner electrode pattern (111), and both the top shielding electrode film (310) and the bottom shielding electrode film (320) include a first shielding electrode pattern (311) and a second shielding electrode pattern (312). The first shielding electrode pattern (311) is connected to the positive electrode (201), and the second shielding electrode pattern (312) is connected to the negative electrode (202). There is a gap between the first shielding electrode pattern (311) and the second shielding electrode pattern (312), and the gap width is d1. The first shielding electrode pattern (311) and the second shielding electrode pattern (312) are arranged symmetrically along the left and right axes.

3. A medium-high voltage multilayer ceramic capacitor for aerospace applications according to claim 2, characterized in that, The margin distance of the inner electrode pattern (111) is d2, where d2 > d1.

4. A medium-high voltage multilayer ceramic capacitor for aerospace applications according to claim 2, characterized in that, The inner electrode pattern (111) is rectangular, and both the first shielding electrode pattern (311) and the second shielding electrode pattern (312) are rectangular.

5. A medium-high voltage multilayer ceramic capacitor for aerospace applications according to claim 4, characterized in that, The corners of the inner electrode pattern (111) are rounded, and the corners of the first shielding electrode pattern (311) and the second shielding electrode pattern (312) facing each other are also rounded.

6. A medium-high voltage multilayer ceramic capacitor for aerospace applications according to claim 5, characterized in that, The rounded corner radius on the inner electrode pattern (111) is 0.5mm≤R≤2mm, and the rounded corner radius on the first shielding electrode pattern (311) and the second shielding electrode pattern (312) is 0.5mm≤R≤2mm.

7. A medium-high voltage multilayer ceramic capacitor for aerospace applications according to any one of claims 1-6, characterized in that, It also includes a first side shielding electrode (330), which includes a first side shielding pattern (331) and a second side shielding pattern (332) disposed on each inner electrode diaphragm (110). The first side shielding pattern (331) and the second side shielding pattern (332) are symmetrically disposed at both ends of a single inner electrode diaphragm (110). The first side shielding pattern (331) and the second side shielding pattern (332) are on the same horizontal straight line and have a distance d1 between them. Both the first side shielding pattern (331) and the second side shielding pattern (332) are located above the inner electrode pattern (111).

8. A medium-high voltage multilayer ceramic capacitor for aerospace applications according to claim 7, characterized in that, It also includes a second side shielding electrode (340), which includes a third side shielding pattern (341) and a fourth side shielding pattern (342) disposed on each inner electrode diaphragm (110). The third side shielding pattern (341) and the fourth side shielding pattern (342) are symmetrically disposed at both ends of a single inner electrode diaphragm (110). The third side shielding pattern (341) and the fourth side shielding pattern (342) are on the same horizontal straight line and have a distance d1 between them. Both the third side shielding pattern (341) and the fourth side shielding pattern (342) are located below the inner electrode pattern (111).

9. A medium-high voltage multilayer ceramic capacitor for aerospace applications according to claim 8, characterized in that, The first side shielding pattern (331) and the second side shielding pattern (332) are arranged in a vertically symmetrical manner with the third side shielding pattern (341) and the fourth side shielding pattern (342).

10. A medium-high voltage multilayer ceramic capacitor for aerospace applications according to claim 4, characterized in that, The first shielding electrode pattern (311) or the second shielding electrode pattern (312) can cover the inner electrode pattern (111) in the direction of width d3.

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