An adaptive voltage equalization thin-film array capacitor

Abstract

This invention discloses an adaptive voltage-equalizing thin-film array capacitor, relating to the field of capacitors. It comprises: multiple composite dielectric films of the same thickness stacked sequentially, each composite dielectric film having a non-uniformly distributed relative permittivity, forming at least two regions with different permittivity; each composite dielectric film has at least two sets of mutually isolated electrode layers, each set of electrode layers corresponding one-to-one with a region on the composite dielectric film with a different permittivity and covering the upper and lower surfaces of the composite dielectric film in that region, thereby forming a capacitor unit in each region. This invention, by inversely relating the non-uniform distribution of permittivity to dielectric strength and matching the electrode layer area, makes the capacitance value of each series-connected capacitor unit adapt to its dielectric strength, thereby achieving adaptive and balanced voltage distribution of each unit without adding external voltage-equalizing components, significantly improving the overall voltage withstand capability and service life of the capacitor.

Description

Technical Field

[0001] This invention relates to a capacitor, and more specifically to an adaptive voltage equalization thin-film array capacitor. Background Technology

[0002] Film capacitors are widely used in pulse power, power electronics, and new energy fields due to their high power density, low loss, and good frequency characteristics. Traditional multilayer film capacitors typically use dielectric films with uniform dielectric constants, and the capacitor cells are directly connected in parallel or series. However, in practical applications, due to material defects, uneven temperature distribution, or aging effects, the withstand voltage (dielectric strength) of each capacitor cell may vary. When a high voltage is applied, the cells with weaker dielectric strength will break down first, leading to the failure of the entire capacitor.

[0003] To address the problem of uneven voltage distribution, existing technologies attempt to achieve voltage equalization among units by connecting voltage-equalizing resistors in parallel with the capacitors or by employing voltage balancing circuits. However, these methods increase the system's size, cost, and energy consumption, and exhibit lag in response under high-frequency or high-voltage transient conditions, resulting in limited voltage equalization effectiveness. Summary of the Invention

[0004] This invention aims to provide an adaptive voltage-equalizing thin-film array capacitor to solve the technical problem of uneven voltage distribution and localized breakdown caused by inconsistent dielectric strengths of individual capacitor units when used in series with existing thin-film capacitors, thus reducing overall withstand voltage reliability. This invention achieves adaptive and balanced voltage distribution of each unit without adding external voltage-equalizing components, significantly improving the overall withstand voltage capability and service life of the capacitor. It inversely correlates the non-uniform distribution of dielectric constant with dielectric strength and matches the electrode layer area, ensuring that the capacitance value of each series capacitor unit is adapted to its dielectric strength.

[0005] To address the above problems, this invention discloses an adaptive voltage equalization thin-film array capacitor, comprising: Multiple composite dielectric films of the same thickness are stacked sequentially. In the planar direction of each composite dielectric film, the relative permittivity is non-uniformly distributed, forming at least two regions with different permittivity, wherein the permittivity of the region is inversely proportional to the permittivity. Each composite dielectric film has at least two sets of mutually isolated electrode layers. Each set of electrode layers corresponds one-to-one with a region on the composite dielectric film with a different dielectric constant and covers the upper and lower surfaces of the composite dielectric film in that region, thereby forming a capacitor unit in each region. From the stacking direction, the electrode layers of adjacent capacitor units are connected to each other to form a series circuit; The area of ​​each electrode layer is matched with the dielectric constant of the composite dielectric film in the area it covers, so that the capacitor cell formed in the region with a lower dielectric constant has a smaller capacitance value, and the capacitor cell formed in the region with a higher dielectric constant has a larger capacitance value.

[0006] In one embodiment of the present invention, the dielectric constant distributions of the plurality of composite dielectric films are all the same, so that when viewed from the stacking direction, the dielectric constants of each capacitor unit in the same series circuit are the same.

[0007] In one embodiment of the present invention, the composite dielectric films of adjacent stacks have alternating regions of high and low dielectric constant. Along the stacking direction, any series branch simultaneously includes a capacitor unit formed by a region of high dielectric constant and a region of low dielectric constant.

[0008] In one embodiment of the present invention, in a plurality of composite dielectric films stacked sequentially, all high dielectric constant regions have the same dielectric constant, and all low dielectric constant regions have the same dielectric constant.

[0009] In one embodiment of the present invention, the electrode layer thickness in the region with lower dielectric constant is greater than the electrode layer thickness in the region with higher dielectric constant.

[0010] In one embodiment of the present invention, each composite dielectric film is further provided with at least one insulating filler strip, which penetrates the composite dielectric film along the thickness direction and is located between the two sets of electrode layers covering the composite dielectric film, so as to isolate the capacitor unit based on the two sets of electrode layers.

[0011] In one embodiment of the present invention, in the composite dielectric film, the dielectric material corresponding to the region with a high dielectric constant is doped with a nonlinear dielectric filler, so that the relative dielectric constant of the region under a high electric field increases with the increase of the electric field strength.

[0012] In one embodiment of the present invention, the nonlinear dielectric filler is barium strontium titanate or silicon carbide micro powder.

[0013] In one embodiment of the present invention, the capacitor further includes two end electrodes, which are respectively disposed on two opposite sides of the stacked body; wherein, the outer electrode layers of the two outermost capacitor units located in the stacking direction extend to the corresponding side and directly contact the end electrodes on the side to form two leads of the entire series circuit.

[0014] In one embodiment of the present invention, a conductive adhesive layer is provided between adjacent capacitor units in the stacked layers from the stacking direction; the conductive adhesive layer covers the electrode layer region of the capacitor unit and does not extend to the region where the insulating filler tape is located.

[0015] The embodiments of the present invention have the following advantages: In this embodiment of the invention, the region with a lower dielectric constant has a higher dielectric strength, and its capacitance is smaller through electrode area matching, so that the capacitor unit can withstand a higher voltage during series voltage division; while the region with a higher dielectric constant has a lower dielectric strength and a larger capacitance, so that it can withstand a lower voltage. In this way, the voltage that each capacitor unit withstands is exactly proportional to its withstand voltage capability, realizing adaptive voltage balance and avoiding local overvoltage breakdown.

[0016] The adaptive voltage-equalizing thin-film array capacitor based on embodiments of the present invention eliminates the need for external voltage-equalizing resistors, achieving automatic voltage balancing from the capacitor's internal structure, saving space and cost, and eliminating additional power consumption. Specifically, the design of high-voltage withstand units effectively avoids the risk of localized overvoltage breakdown caused by capacitance variations in traditional capacitors, significantly improving the overall operating voltage and lifespan of the array. Furthermore, it transforms unavoidable manufacturing tolerances into designable and usable parameters, reducing the stringent requirements for thin-film uniformity and process consistency. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application.

[0018] Figure 1 This is a schematic diagram of the dielectric constant region distribution of a composite dielectric thin film according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the dielectric constant region distribution of a composite dielectric thin film according to another embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of an adaptive voltage equalization thin-film array capacitor according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an adaptive voltage equalization thin-film array capacitor according to another embodiment of the present invention; Figure 5 This is an equivalent connection diagram of the capacitor unit in one embodiment of the present invention; Figure 6 This is an equivalent connection diagram of the capacitor unit in another embodiment of the present invention. Detailed Implementation

[0019] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0020] Hereinafter, the terms "second," "first," etc., are used for descriptive convenience only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "second," "first," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0021] In the embodiments of this application, unless otherwise expressly specified and limited, the term "connection" should be interpreted broadly, and can refer to direct connection or indirect connection through an intermediate medium.

[0022] In this embodiment of the application, "and / or" describes the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

[0023] This invention discloses an adaptive voltage equalization thin-film array capacitor, with reference to... Figures 1-6 The method includes: multiple composite dielectric films stacked sequentially with the same thickness; in the planar direction of each composite dielectric film, the relative permittivity is non-uniformly distributed, forming at least two regions with different permittivity, wherein the permittivity of the region is inversely proportional to the dielectric strength; each composite dielectric film has at least two sets of mutually isolated electrode layers, each set of electrode layers corresponding one-to-one with the region with different permittivity on the composite dielectric film and covering the upper and lower surfaces of the composite dielectric film in that region, thereby forming a capacitor unit in each region; from the stacking direction, the electrode layers of adjacent capacitor units are interconnected to form a series circuit; wherein the area of ​​each set of electrode layers matches the permittivity of the composite dielectric film in the region it covers, so that the capacitor unit formed in the region with lower permittivity has a smaller capacitance value, and the capacitor unit formed in the region with higher permittivity has a larger capacitance value.

[0024] In this invention, a composite dielectric film refers to a thin film layer composed of multiple dielectric materials, used to form the dielectric of a capacitor. Through processes such as gradient doping and irradiation modification, its dielectric constant can be made non-constant within the film plane, thus forming a non-uniform distribution. By stacking these composite dielectric films layer by layer along their thickness direction, multiple composite dielectric films arranged in sequence are formed, i.e., a stacked structure.

[0025] The relative permittivity is a physical quantity characterizing the degree of polarization of a dielectric material in an electric field. Non-uniform distribution refers to the fact that the permittivity values ​​differ at different planar locations on the same thin film, naturally dividing it into regions of high and low permittivity. In one example, such as... Figure 1 As shown, a composite dielectric film contains only two dielectric constant regions: the left half is a high dielectric constant region, and the right half is a low dielectric constant region. In another example, such as... Figure 2 As shown, a composite dielectric film has four dielectric constant regions, which are distributed alternately from left to right along the plane of the composite dielectric film, for example, from left to right. The number of dielectric constant regions on each composite dielectric film can be odd, even, or more than four; this invention does not limit this.

[0026] It is worth noting that, for the sake of simplifying the process, in this embodiment of the invention, all high dielectric constant regions have the same dielectric constant, and all low dielectric constant regions have the same dielectric constant. Therefore, the terms "low dielectric constant region" and "high dielectric constant region" as used in this invention are relative. Regions with dielectric constants lower than other regions are called low dielectric constant regions; regions with dielectric constants higher than other regions are called high dielectric constant regions. Those skilled in the art can design capacitors based on their operating voltage range and capacitance standards.

[0027] Regarding the dielectric constant regions on the same composite dielectric film, which are not shown in the figure, they can be distributed in a lattice or a ring, etc. Among the multiple dielectric constant regions that are distributed in a lattice or a ring, there is at least one high dielectric constant region and at least one low dielectric constant region.

[0028] The dielectric constant of each region is inversely proportional to its dielectric strength. In this field, dielectric strength generally refers to the maximum electric field strength that a dielectric material can withstand without breakdown. For a single region, the dielectric constant and dielectric strength are inversely proportional; specifically, regions with higher dielectric constants have lower dielectric strengths, and vice versa. In practical implementations, this inverse relationship between dielectric constant and dielectric strength can be achieved by utilizing the inherent physical properties of the material itself (generally, materials with high dielectric constants tend to have lower breakdown voltages, while materials with low dielectric constants tend to have higher breakdown voltages).

[0029] In an embodiment of the present invention, reference is made to Figure 3 and Figure 4Each composite dielectric film has at least two sets of mutually isolated electrode layers. The electrode layers are thin layers formed of conductive materials (such as metals, conductive oxides, etc.) used to conduct charge. Each set of electrode layers includes an upper electrode layer and a lower electrode layer. The upper electrode layer covers the upper surface of its corresponding region on the composite dielectric film, and the lower electrode layer covers the lower surface of its corresponding region on the composite dielectric film. Due to the non-uniform distribution of relative permittivity within the same composite dielectric film, at least two regions with different permittivity are formed. Therefore, each composite dielectric film has at least two sets of mutually isolated electrode layers, i.e., at least four electrode layers: two upper electrode layers and two lower electrode layers. One set of electrode layers corresponds to the region with a lower permittivity on the composite dielectric film, and the other set of electrode layers corresponds to the region with a higher permittivity. When one set of electrode layers covers the corresponding region of the composite dielectric film, a capacitor unit is formed. Interconnection of the electrode layers of adjacent capacitor units means that the lower electrode layer of one capacitor unit is directly or indirectly connected to the upper electrode layer of the next capacitor unit, so that the capacitor units are connected end-to-end, forming a series circuit.

[0030] In this design, the area of ​​each electrode layer is matched to the dielectric constant of the composite dielectric film in the area it covers. This can be understood as adjusting the capacitance value of each capacitor unit by designing the size of the electrode area, so that it is consistent with the trend of the dielectric constant. That is, the capacitor unit formed in the region with the lower dielectric constant has a smaller capacitance value, and the capacitor unit formed in the region with the higher dielectric constant has a larger capacitance value.

[0031] According to the capacitance calculation formula, the capacitance value of a capacitor cell is positively correlated with its electrode layer area and also positively correlated with its dielectric constant. To achieve smaller capacitance values ​​for capacitor cells formed in regions with lower dielectric constants and larger capacitance values ​​for capacitor cells formed in regions with higher dielectric constants, in one feasible approach, assuming the thickness of each composite dielectric film is the same, the electrode layer area corresponding to each region is the same. In this case, the capacitance value of the capacitor cell is linearly positively correlated with the dielectric constant. In other feasible approaches, the area of ​​the low dielectric constant region can be designed to be smaller, and the area of ​​the high dielectric constant region to be larger, resulting in a greater difference in capacitance values ​​between different regions.

[0032] In a series capacitor circuit, the voltage across each capacitor cell is inversely proportional to its capacitance (i.e., the larger the capacitance, the smaller the voltage received, and vice versa). Therefore, in this embodiment of the invention, regions with lower dielectric constants have higher dielectric strength, and their capacitance is smaller through electrode area matching, allowing these capacitor cells to withstand higher voltages during series voltage division. Conversely, regions with higher dielectric constants have lower dielectric strength and larger capacitance, allowing them to withstand lower voltages. In this way, the voltage across each capacitor cell is directly proportional to its withstand voltage capability, achieving adaptive voltage balance and preventing localized overvoltage breakdown.

[0033] The adaptive voltage-equalizing thin-film array capacitor based on embodiments of the present invention eliminates the need for external voltage-equalizing resistors, achieving automatic voltage balancing from the capacitor's internal structure, saving space and cost, and eliminating additional power consumption. Specifically, the design of high-voltage withstand units effectively avoids the risk of localized overvoltage breakdown caused by capacitance variations in traditional capacitors, significantly improving the overall operating voltage and lifespan of the array. Furthermore, it transforms unavoidable manufacturing tolerances into designable and usable parameters, reducing the stringent requirements for thin-film uniformity and process consistency.

[0034] In one embodiment of the present invention, such as Figure 3 As shown, the dielectric constant distributions of the multiple composite dielectric films are identical, ensuring that, viewed from the stacking direction, the dielectric constants of each capacitor unit in the same series circuit are the same. In this embodiment, the identical dielectric constant distributions of the multiple composite dielectric films can be understood as the high and low dielectric constant regions of all composite dielectric films used in the stack having completely identical or corresponding shapes, sizes, and relative positions within the film plane. This ensures that, viewed from the stacking direction (i.e., from a top view along the thickness direction), each capacitor unit traversed by the same series circuit (e.g., the branch formed by the series connection of capacitor units corresponding to the upper left corner regions of all films) has the same dielectric constant characteristics (high and low). This aligned stacking method ensures that each series branch is composed of capacitor units with completely identical characteristics, resulting in good circuit symmetry, simple design and analysis, and easy batch fabrication of electrodes using a unified mask or patterning process, thus simplifying the manufacturing process. Figure 3 In the diagram, the region with low dielectric constant is denoted by L, and the region with high dielectric constant is denoted by H.

[0035] In another embodiment of the invention, such as Figure 4As shown, in the composite dielectric films of adjacent stacks, regions with high and low dielectric constants are arranged alternately. Along the stacking direction, any series branch simultaneously contains capacitor units formed by both high and low dielectric constant regions. In this embodiment, the alternating arrangement means that the high and low dielectric constant regions of adjacent composite dielectric films are not aligned in the planar projection, but are staggered. For example, in the first layer, the high dielectric constant region is on the left and the low dielectric constant region is on the right; in the second layer, the high dielectric constant region is on the right and the low dielectric constant region is on the left, and so on. When the high and low regions are arranged alternately, each series branch contains both capacitor units with high dielectric constant (low dielectric strength) and capacitor units with low dielectric constant (high dielectric strength). Since the dielectric constant and dielectric strength are inversely proportional, the inverse relationship between the withstand voltage and capacitance of each unit compensates for each other within the branch, making the voltage distribution of the entire branch smoother. Meanwhile, this staggered arrangement avoids the vertical alignment of low-dielectric-constant regions of all thin films, which would lead to excessive concentration of local electric fields. This further optimizes the electric field distribution, reduces local hot spots, and improves the capacitor's dielectric strength and reliability. Figure 4 In the diagram, the region with low dielectric constant is denoted by L, and the region with high dielectric constant is denoted by H.

[0036] In some embodiments of the present invention (not shown in the figures), the electrode layer thickness in regions with lower dielectric constants is greater than that in regions with higher dielectric constants. In this embodiment, regions with lower dielectric constants have higher dielectric strength, enabling them to withstand higher voltages, and correspondingly, smaller capacitance values ​​for the capacitor cells (according to the design of claim 1). They withstand higher voltages in series circuits. Increasing the thickness of the electrode layer in these regions improves the conductivity and heat dissipation performance of the electrodes, preventing overheating and oxidation due to excessive voltage, thereby enhancing the voltage withstand stability of the capacitor cells. Conversely, regions with higher dielectric constants have lower dielectric strength, corresponding to larger capacitance values ​​for the capacitor cells, and withstand lower voltages. Therefore, thinner electrode layers can be used, reducing the amount of electrode material used while maintaining conductivity, lowering costs, and simultaneously reducing the overall thickness of the capacitor.

[0037] Without an insulating filler strip, two regions with different dielectric constants on the same composite dielectric film are directly adjacent. During high-voltage operation, electric field distortion occurs at the interface between the two materials with different dielectric constants. The electric field lines are more concentrated on the side with the lower dielectric constant, and the local field strength may reach several times the average field strength. This distortion may cause current to creep along the interface surface instead of penetrating the dielectric, leading to surface breakdown. Therefore, in some embodiments of the present invention, each composite dielectric film is further provided with at least one insulating filler strip. The insulating filler strip penetrates the composite dielectric film along its thickness direction and is located between two sets of electrode layers covering the composite dielectric film to isolate the capacitor unit formed based on the two sets of electrode layers. The insulating filler strip refers to a strip-shaped isolation structure formed by filling with an insulating material (such as silicon oxide, polyimide, etc.) for capacitor units formed based on the same composite dielectric film. For example, as shown... Figure 1 and Figure 2 As shown, the composite dielectric film has two dielectric constant regions: a high dielectric constant region and a low dielectric constant region. The low dielectric constant region is located on the left side of the composite dielectric film, with electrode layers on both its upper and lower surfaces, forming a capacitor unit. The high dielectric constant region is located on the right side of the composite dielectric film, with electrode layers on both its upper and lower surfaces, forming another capacitor unit. There is a gap between the electrode layers of the two capacitor units, without electrode coverage. In this embodiment, an insulating filler tape is placed precisely in this gap, penetrating the composite dielectric film from top to bottom, completely separating the two dielectric constant regions. This blocks the surface discharge path between adjacent capacitor units, completely isolating each unit physically and electrically. This significantly improves the insulation withstand voltage between the high and low dielectric constant regions, prevents interface breakdown, and improves the overall reliability of the capacitor.

[0038] In one embodiment of the present invention, in the composite dielectric film, the dielectric material corresponding to the region with a high dielectric constant is doped with a nonlinear dielectric filler, so that the relative dielectric constant of this region increases with the increase of the electric field strength under a high electric field. Based on the present invention, the dielectric strength of the high dielectric constant region is low, the corresponding capacitance value of the capacitor unit is large, and the voltage it withstands in the series circuit is low. However, in actual operation, due to the fluctuation of the electric field distribution, there may be a local increase in the electric field strength (i.e., a high electric field environment). If conventional materials are used in the high dielectric constant region, their dielectric constant is fixed and may not be able to adapt to the change in electric field, leading to further concentration of the local electric field. However, after doping with the nonlinear dielectric filler, under a high electric field, the relative dielectric constant of this region will increase with the increase of the electric field strength. According to the capacitance formula, the capacitance value is proportional to the dielectric constant, and the capacitance value will increase with the dielectric constant. According to the voltage division principle of series capacitors, the voltage across the capacitor unit with the increased capacitance value will decrease, thereby automatically offsetting the effect of the local increase in electric field and realizing adaptive voltage equalization of the electric field. Therefore, this invention achieves adaptive adjustment of the electric field. When the local electric field increases, the voltage across the corresponding capacitor unit can be automatically reduced, avoiding local electric field concentration and further improving the voltage equalization effect. This invention can improve the capacitor's adaptability to electric field fluctuations and enhance its stability in high-voltage and complex electric field environments. The entire implementation process requires no additional adjustment devices, achieving further optimization of adaptive voltage equalization and improving the overall performance of the capacitor.

[0039] Optionally, the nonlinear dielectric filler can be barium strontium titanate or silicon carbide micropowder. Barium strontium titanate is a typical perovskite ferroelectric material with excellent nonlinear dielectric properties; its relative permittivity changes significantly with the electric field strength. Silicon carbide micropowder is an inorganic nonmetallic material with good nonlinear dielectric properties and high-temperature and corrosion resistance. Doping it into dielectric materials can effectively adjust the dielectric properties of the medium. Both barium strontium titanate and silicon carbide micropowder have excellent nonlinear dielectric properties. Doping them into dielectric materials in the high dielectric constant region can increase the relative permittivity of that region with increasing electric field strength under high electric fields. Among them, barium strontium titanate has a higher nonlinear dielectric constant, making it suitable for scenarios with high voltage equalization accuracy requirements; silicon carbide micropowder has better high-temperature and corrosion resistance, making it suitable for applications in high-temperature and harsh environments. Choosing one of these two materials allows for flexible adjustment of the composite dielectric film's performance according to the specific application requirements, ensuring the achievement of adaptive voltage equalization.

[0040] In an embodiment of the present invention, reference is made to Figure 5 and Figure 6The capacitor further includes two end electrodes, respectively disposed on two opposite sides of the stack; wherein, the outer electrode layers of the two outermost capacitor units in the stacking direction extend to their respective sides and directly contact the end electrodes on those sides, forming two leads of the entire series circuit. Figure 3 and Figure 4 The structure shown, based on the core concept of this invention, comprises multiple series circuits (each composite dielectric film forms at least two capacitor units, which are stacked to form multiple independent series circuits). When all series circuits are connected to these two terminal electrodes, a structure of multiple series circuits connected in parallel is formed. The parallel connection of multiple series circuits compensates for the small capacitance of series circuits, allowing the capacitor to simultaneously meet high voltage withstand and sufficient capacity, adapting to the practical application requirements of high-voltage power electronic equipment. On one hand, the parallel structure of multiple series circuits formed in this embodiment improves reliability. When a single series circuit fails (such as a capacitor unit breaking down), the remaining series circuits can still operate normally, preventing the entire capacitor from failing completely, thus providing stronger fault tolerance. On the other hand, it optimizes current distribution. The parallel connection of multiple branches can disperse the total current, avoiding excessive current in a single series circuit that leads to overheating and aging, thereby extending the capacitor's lifespan. Figure 5 and Figure 6 In the diagram, the region with low dielectric constant is denoted by L, and the region with high dielectric constant is denoted by H.

[0041] In this embodiment of the invention, a conductive adhesive layer is disposed between adjacent capacitor units in the stacked structure, from the stacking direction. The conductive adhesive layer covers the electrode layer region of the capacitor unit but does not extend into the region where the insulating filler strip is located. This embodiment utilizes the conductive adhesive layer to achieve conductive connection between electrode layers, ensuring smooth current transmission, and also to bond adjacent composite dielectric films together, fixing the stacked structure and improving the mechanical stability of the capacitor. Furthermore, by specifying that the conductive adhesive layer only covers the electrode layer region and does not extend into the region where the insulating filler strip is located, the insulating isolation effect of the insulating filler strip can be avoided.

[0042] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0043] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand this application, and the content of this specification should not be construed as a limitation of this application. Furthermore, for those skilled in the art, there will be different forms of changes in the specific implementation methods and application scope based on this application. It is neither necessary nor possible to exhaustively list all implementation methods here, and obvious changes or modifications derived therefrom are still within the protection scope of this application.

Claims

1. An adaptive voltage equalization thin-film array capacitor, characterized in that, include: Multiple composite dielectric films of the same thickness are stacked sequentially. In the planar direction of each composite dielectric film, the relative permittivity is non-uniformly distributed, forming at least two regions with different permittivity, wherein the permittivity of the region is inversely proportional to the permittivity. Each composite dielectric film has at least two sets of mutually isolated electrode layers. Each set of electrode layers corresponds one-to-one with a region on the composite dielectric film with a different dielectric constant and covers the upper and lower surfaces of the composite dielectric film in that region, thereby forming a capacitor unit in each region. From the stacking direction, the electrode layers of adjacent capacitor units are connected to each other to form a series circuit; The area of ​​each electrode layer is matched with the dielectric constant of the composite dielectric film in the area it covers, so that the capacitor cell formed in the region with a lower dielectric constant has a smaller capacitance value, and the capacitor cell formed in the region with a higher dielectric constant has a larger capacitance value.

2. The adaptive voltage equalization thin-film array capacitor according to claim 1, characterized in that, The dielectric constants of the multiple composite dielectric films are all the same, so that when viewed from the stacking direction, the dielectric constants of each capacitor unit in the same series circuit are the same.

3. The adaptive voltage equalization thin-film array capacitor according to claim 1, characterized in that, In the composite dielectric thin film of adjacent stacks, regions with high and low dielectric constants are arranged alternately. Along the stacking direction, any series branch simultaneously contains a capacitor unit formed by regions with high and low dielectric constants.

4. The adaptive voltage equalization thin-film array capacitor according to claim 1, characterized in that, In a composite dielectric film stacked in sequence, all regions with high dielectric constant have the same dielectric constant, and all regions with low dielectric constant have the same dielectric constant.

5. The adaptive voltage equalization thin-film array capacitor according to claim 1, characterized in that, The electrode layer thickness in regions with lower dielectric constants is greater than that in regions with higher dielectric constants.

6. The adaptive voltage equalization thin-film array capacitor according to claim 1, characterized in that, Each composite dielectric film is also provided with at least one insulating filler strip, which penetrates the composite dielectric film along the thickness direction and is located between the two sets of electrode layers covering the composite dielectric film, so as to isolate the capacitor unit based on the two sets of electrode layers.

7. The adaptive voltage equalization thin-film array capacitor according to claim 1, characterized in that, In the composite dielectric film, the dielectric material corresponding to the region with a high dielectric constant is doped with a nonlinear dielectric filler, so that the relative dielectric constant of the region increases with the increase of the electric field strength under a high electric field.

8. The adaptive voltage equalization thin-film array capacitor according to claim 7, characterized in that, The nonlinear dielectric filler is barium strontium titanate or silicon carbide micro powder.

9. The adaptive voltage equalization thin-film array capacitor according to claim 1 or 2, characterized in that, The capacitor also includes two end electrodes, which are respectively disposed on two opposite sides of the laminate. In this circuit, the outer electrode layers of the two outermost capacitor units located in the stacking direction extend to their respective sides and directly contact the end electrodes on those sides, forming the two leads of the entire series circuit.

10. The adaptive voltage equalization thin-film array capacitor according to claim 1 or 6, characterized in that, From the stacking direction, a conductive adhesive layer is provided between adjacent capacitor units in the stack; the conductive adhesive layer covers the electrode layer area of ​​the capacitor unit and does not extend to the area where the insulating filler tape is located.

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