Thin-film polymer multilayer capacitor element and method for manufacturing same

Abstract

The purpose of the present invention is to provide a thin-film polymer multilayer capacitor element in which small size, high voltage, and large current are satisfactorily achieved.　Provided is a thin-film polymer multilayer capacitor element having: a laminate in which a plurality of dielectric layers and a plurality of internal electrode metal layers are alternately laminated; and external electrodes formed at both ends of the laminate in the length direction. Each of the internal electrode metal layers has a plurality of metal regions separated by margin portions, and an internal series structure having a plurality of capacitance appearance portions is formed. Each of the metal regions forming the internal series structure has an active length of 1.8 mm to 5.2 mm along the length direction.

Description

Thin-film polymer multilayer capacitor element and method for manufacturing the same

[0001] The present invention relates to a thin-film polymer multilayer capacitor element and a method for manufacturing the same.

[0002] Conventionally, film capacitors using thermoplastic resins such as polypropylene (PP) as dielectrics are known. These dielectrics can offer advantages such as low loss.

[0003] On the other hand, thin-film polymer multilayer capacitor elements are known, which generally have a structure in which dielectric layers containing thermosetting resin (resin thin film layers) and electrode layers containing metal (metal thin film layers) are alternately stacked, and can provide better heat resistance than conventional film capacitors using thermoplastic resin as the dielectric. Conventionally, thin-film polymer multilayer capacitor elements with improved electrical characteristics by having a heavy edge structure and an internal series structure are known.

[0004] Patent Document 1 describes a thin-film polymer laminated capacitor element in which a heavy-edge structure is formed by vapor-depositing another metal layer onto the portion of one metal layer that is connected to the external electrode. Furthermore, one embodiment described has an internal series structure.

[0005] Japanese Patent Publication No. 2021-019133

[0006] Conventional film capacitors used in inverter circuits for automotive, solar power, and other applications sometimes failed to meet sufficient performance requirements in terms of small size, high voltage, and high current tolerance.

[0007] Against this backdrop, the object of this disclosure is to provide a thin-film polymer multilayer capacitor element that can successfully meet the requirements of small size, high voltage, and high current.

[0008] The problems of this disclosure can be solved by the following embodiments of the invention: <Embodiment 1> A thin-film polymer laminated capacitor element having a laminate in which a plurality of dielectric layers and a plurality of internal electrode metal layers are alternately stacked, and a pair of external electrodes formed at both ends in the longitudinal direction of the laminate, wherein each of the internal electrode metal layers has a plurality of metal regions separated by a margin portion, and the respective metal regions of two adjacent internal electrode metal layers across the dielectric layer are offset in the longitudinal direction of the laminate, thereby forming an internal series structure having a plurality of capacitance appearance portions, and the metal regions forming the internal series structure have an active length of 1.8 mm to 5.2 mm along the longitudinal direction. <Embodiment 2> The thin-film polymer laminated capacitor element according to Embodiment 1, wherein each of the plurality of dielectric layers has a thickness of 0.4 to 0.8 μm. <Embodiment 3> The thin-film polymer laminated capacitor element according to Embodiment 1 or 2, wherein each of the plurality of internal electrode metal layers has a deposition resistance value of 25 to 45 Ω / □. <Aspect 4> A thin-film polymer multilayer capacitor element according to any one of aspects 1 to 3, wherein the dielectric layer comprises a polymer of a monomer having an acrylic group or a methacrylic group. <Aspect 5> A thin-film polymer multilayer capacitor element according to any one of aspects 1 to 4, wherein the number of internal series connections in the internal series structure is 2 to 12. <Aspect 6> A thin-film polymer multilayer capacitor element according to any one of aspects 1 to 5, wherein the metal region of the internal electrode metal layer forms a heavy edge in the end region on the external electrode side. <Aspect 7> A thin-film polymer multilayer capacitor element according to any one of aspects 1 to 6, having a dielectric breakdown voltage (BDV) of 400 V / μm or more. <Aspect 8> A thin-film polymer multilayer capacitor element according to any one of aspects 1 to 7, having an allowable ripple current of 0.4 Arms / μF or more. <Aspect 9> A volume of 1.0 to 3.2 cm³ per unit energy (J) ３A thin-film polymer laminated capacitor element according to Embodiment 8, having and / or having 1,000 to 8,000 layers, with one dielectric layer and one internal electrode metal layer forming one layer. Embodiment 10 A thin-film polymer laminated capacitor element according to any one of Embodiments 1 to 9 for use at a voltage of 400 to 1200 VDC. <Aspect 11> A method for manufacturing a thin-film polymer multilayer capacitor element, comprising: (a) forming a dielectric layer; (b) applying a patterning oil on the dielectric layer and then depositing a metal to form an internal electrode metal layer having a metal region separated by a margin; and (c) continuously and alternately repeating the formation of the dielectric layer and the formation of the internal electrode metal layer in a vacuum to form a laminate, wherein in (c), an internal series structure is formed by stacking two adjacent internal electrode metal layers such that the respective metal regions of the laminate are offset in the longitudinal direction of the laminate, and the metal regions forming the internal series structure have an active length of 1.8 mm to 5.2 mm along the longitudinal direction of the laminate, the method for manufacturing a thin-film polymer multilayer capacitor element.

[0009] According to the present invention, it is possible to provide a thin-film polymer multilayer capacitor element that can successfully satisfy the requirements of being small, high-voltage, and high-current.

[0010] Figure 1 shows a schematic perspective view of an example of a thin-film polymer multilayer capacitor element according to the present invention. Figure 2 shows yet another schematic perspective view of a thin-film polymer multilayer capacitor element according to the present invention. Figure 3 shows the results of allowable ripple current measurement and the relationship between the module volume and active length for examples and comparative examples of module bodies using the thin-film polymer multilayer capacitor element according to the present invention.

[0011] <<Thin-film polymer multilayer capacitor>> The invention relating to this disclosure is a thin-film polymer multilayer capacitor, which has a laminate formed by alternately stacking a plurality of dielectric layers and a plurality of internal electrode metal layers, and a pair of external electrodes formed at both ends in the longitudinal direction of the laminate, wherein each internal electrode metal layer has a plurality of metal regions separated by a margin portion, and the metal regions of two adjacent internal electrode metal layers separated by a dielectric layer are offset in the longitudinal direction of the laminate, thereby forming an internal series structure having a plurality of capacitance appearance portions, and the metal regions forming the internal series structure have an active length of 1.8 mm to 5.2 mm along the longitudinal direction.

[0012] In one embodiment, each metal region forming the internal series structure has an active length of 1.8 mm to 5.2 mm along the longitudinal direction.

[0013] In the present invention, "active length" means the effective length of the metal region of the internal electrode metal layer constituting the internal series structure, that is, half the total length of the portion of a single metal region that contributes to the capacitor function (the portion corresponding to the capacitance appearance site).

[0014] In the case of film capacitors using polypropylene (PP), the thinnest film thickness that can be reliably obtained at present is about 2 microns. In this case, even assuming an operating voltage of less than 500V, miniaturization of the capacitor is difficult. On the other hand, with thin-film polymer multilayer capacitor elements, by using a vapor-deposited dielectric, the dielectric thickness can be as thin as 0.2 microns, making miniaturization possible depending on the desired voltage.

[0015] Conventional thin-film polymer multilayer capacitor elements addressed high voltage requirements by selecting the desired number of internal series connections within the range of film thickness that could be fabricated, thereby achieving the desired withstand voltage. Furthermore, it was claimed that good electrical characteristics (tanδ, ESR) could be obtained by introducing a heavy-edge structure.

[0016] However, these methods alone made it difficult to achieve both miniaturization and high current capacity in thin-film polymer multilayer capacitor elements that use dielectric materials with relatively higher losses than conventional film capacitors using thermoplastic resins such as polypropylene. Furthermore, reducing the aluminum deposition resistor in order to increase the current capacity significantly reduces the voltage withstand capability.

[0017] In contrast, the thin-film polymer laminated capacitor element according to the present invention achieves miniaturization, high voltage, and high current by having the above-described configuration. Although not limited to theory, it is believed that the thin-film polymer laminated capacitor element according to the present invention improves withstand voltage through its internal series structure and optimizes the active length, thereby maximizing the use of the internal series structure, and thereby achieving miniaturization, high voltage, and high current.

[0018] More specifically, in this invention, by setting the active length of the internal series structure to be relatively small (5.2 mm or less), the capacitance per layer is suppressed for a given capacitance, and it is thought that the number of layers can be increased relatively. As the number of layers increases, the metal ratio in the same volume increases, so it is presumed that the ESR is reduced, and thereby the heat generated when ripple current flows is reduced.

[0019] Furthermore, in this invention, by setting the active length of the internal series structure to a range that does not become excessively small (1.8 mm or more), it is presumed that the thin-film polymer multilayer capacitor element can be miniaturized without increasing the number of layers excessively or increasing the margin ratio per internal electrode metal layer excessively. If the number of layers increases excessively, the volume becomes excessively large, making it difficult to meet the requirements for miniaturization.

[0020] Conventionally, it was thought that making the size (length) of each capacitance-generating portion of the internal series structure relatively small could lead to a decrease in capacitance or an increase in volume due to an increase in the margin portion. In contrast, in the present invention, by setting the active length of the internal series structure within a specific range, it is believed that such adverse effects can be avoided or minimized, and the requirements for small size, high voltage, and high current can be well met.

[0021] The thin-film polymer laminated capacitor element according to the present invention has, in particular, a dielectric breakdown voltage (BDV) of 400 V / μm or more and / or an allowable ripple current of 0.4 Arms / μF or more.

[0022] The capacitor of the present invention will be described with reference to the drawings. The drawings are illustrative and not limiting to the present invention. The drawings are not to scale.

[0023] Figure 1 shows a schematic cross-sectional view of an example of a thin-film polymer multilayer capacitor element according to the present invention. The thin-film polymer multilayer capacitor element 10a according to the present invention has a dielectric layer 101a, an internal electrode metal layer 102a, and an external electrode 103a. A laminate 104a is formed by alternately stacking a plurality of dielectric layers and a plurality of internal electrode metal layers, and the external electrodes 103a are formed on one end and the other end of this laminate 104a in the longitudinal direction. In the figure, the dimensions of "width W", "height H", and "length L" are shown. In Figure 1, the number of series connections in the internal series structure is 4.

[0024] The internal electrode metal layer 102a has a plurality of metal regions 106a separated by a margin portion 105a indicated by a circle in the figure, and the metal regions 106a of two adjacent internal electrode metal layers 102a that are separated by a dielectric layer 101a are stacked with a longitudinal offset, thereby forming an internal series structure having a plurality of capacitance appearance portions. The capacitance appearance portion 107a of the internal series structure has an active length of 1.8 to 5.2 mm.

[0025] In Figure 1, the lengths A1 and A2 (in the longitudinal direction of the laminate) of the two capacitance-emerging portions 107a formed by one metal region are the same, and the active length = A1 = A2. The active length can also be expressed as (A1 + A2) / 2.

[0026] Figure 2 shows a schematic cross-sectional view of another example of a thin-film polymer multilayer capacitor element according to the present invention. The only difference from Figure 1 is that in the thin-film polymer multilayer capacitor element 20 according to the present invention, the internal electrode metal layer 202 forms a heavy edge 209 in the end region 208. The heavy edge 209 provides good connectivity between the internal electrode metal layer and the external electrode, good voltage withstand characteristics, and a desired capacitance in a thin-film polymer multilayer capacitor element.

[0027] The components of the present invention will be described in more detail below.

[0028] <Basic Structure of Thin-Film Polymer Multilayer Capacitors> A thin-film polymer multilayer capacitor has a laminate formed by alternately stacking multiple dielectric layers and multiple internal electrode metal layers, and external electrodes formed at both ends in the longitudinal direction of the laminate.

[0029] <Dielectric Layer> A thin-film polymer multilayer capacitor includes a plurality of dielectric layers. The dielectric layers may contain a curable resin, for example, a UV-curable resin and / or a thermosetting resin.

[0030] The dielectric layer is often formed using monomers having acrylic groups or methacrylic groups. Preferably, the dielectric layer contains a polymer of monomers having acrylic groups or methacrylic groups. Examples of such monomers include diacrylate / dimethacrylate compounds having an alicyclic hydrocarbon skeleton. In particular, examples of such monomers include dicyclopentadiene methanol diacrylate, tricyclodecane dimethanol diacrylate, and tricyclodecane dimethanol dimethacrylate.

[0031] In one embodiment, the dielectric layer has a polymer structure obtained by polymerizing a first monomer which is a monofunctional monomer, a second monomer which is a difunctional monomer, and a third monomer which is a trifunctional or polyfunctional monomer. For example, the first monomer may include 2-(biphenyl-2-yloxy)-ethyl acrylate, 4-phenylbenzyl acrylate, stearyl acrylate, or stearyl methacrylate, the second monomer may include tricyclodecanedimethanol diacrylate or tricyclodecanedimethanol dimethacrylate, and / or the third monomer may include triallyl isocyanurate.

[0032] In one embodiment, each dielectric layer may have a thickness of 0.4 to 0.8 μm, preferably 0.50 to 0.75 μm, and more preferably 0.5 to 0.7 μm. This makes it possible to provide a thin-film polymer laminated capacitor element that has the desired high-voltage resistance and is sufficiently miniaturized, while also enabling stable production.

[0033] <Internal Electrode Metal Layers> Thin-film polymer multilayer capacitors include multiple internal electrode metal layers. Each internal electrode metal layer has multiple metal regions separated by margins.

[0034] (Internal series structure) In the thin-film polymer laminated capacitor according to the present invention, the metal regions of two internal electrode metal layers that are adjacent to each other via a dielectric layer are stacked with a longitudinal offset, thereby forming an internal series structure having multiple capacitance appearance regions.

[0035] In an internal series structure, among adjacent metal regions that are offset from each other in the longitudinal direction, the portion that overlaps in the stacking direction functions as a capacitor. The term "capacitance emergence region" refers to this portion that functions as a capacitor.

[0036] In one embodiment, the number of internal series structures may be 2 to 12, preferably 2 to 10, and more preferably 2 to 8. Increasing the number of internal series structures can reduce the capacitance per layer while improving the voltage resistance.

[0037] (Active length) The active length can be changed, for example, by adjusting the oil nozzle pitch and the length of the oil margin (margin length) when applying the patterning oil during the manufacturing process of the capacitor.

[0038] The "active length" can also be calculated by the following formula: Active length = (patterning oil pitch) / 2 - (oil margin length) (unit "mm").

[0039] The metal region with an internal serial structure has an active length of 1.8 mm to 5.2 mm, preferably a length (active length) of 2.0 mm to 5.0 mm or 2.5 to 4.5 mm, or further 3.0 to 4.0 mm. This length (active length) may be 1.9 mm or more, 2.0 mm or more, 2.1 mm or more, 2.2 mm or more, 2.3 mm or more, 2.4 mm or more, 2.5 mm or more, 2.6 mm or more, 2.7 mm or more, 2.8 mm or more, 2.9 mm or more, 3.0 mm or more, 3.1 mm or more, 3.2 mm or more, 3.3 mm or more, or 3.4 mm or more, and / or 5.1 mm or less, 5.0 mm or less, 4.9 mm or less, 4.8 mm or less, 4.7 mm or less, 4.6 mm or less, 4.5 mm or less, 4.4 mm or less, 4.3 mm or less, 4.2 mm or less, 4.1 mm or less, 4.0 mm or less, 3.9 mm or less, 3.8 mm or less, 3.7 mm or less, or 3.6 mm or less.

[0040] (Margin part) The margin part divides each internal electrode metal layer constituting the thin-film polymer laminated capacitor into a plurality of metal regions. The margin part can be formed, for example, by depositing a metal material after applying the patterning oil on the dielectric layer during the manufacturing process of the capacitor. The margin part is usually formed of the material constituting the dielectric layer.

[0041] In one aspect, the margin part may have a length of 0.1 to 1.2 mm or further 0.2 to 0.8 mm in the length direction L of the thin-film polymer laminated capacitor element, preferably a length of 0.3 to 0.5 mm.

[0042] (Metallic Regions) Metallic regions are areas separated from each other by margins within the internal electrode metal layers that constitute a thin-film polymer multilayer capacitor. Metallic regions can be formed, for example, by depositing metal onto a dielectric layer coated with patterning oil during the capacitor manufacturing process.

[0043] In one embodiment, the metal region may have a length of 4 to 11 mm in the longitudinal direction L of the thin-film polymer laminated capacitor element, preferably 6 to 9 mm. The length of the metal region can be changed by adjusting the oil nozzle pitch and the length of the oil margin (margin length) when applying patterning oil during the capacitor manufacturing process.

[0044] Examples of metal materials constituting the metal region of the internal electrode metal layer include at least one selected from the group consisting of aluminum (Al), copper (Cu), zinc (Zn), tin (Sn), gold (Au), silver (Ag), and platinum (Pt), as well as combinations thereof. The metal material constituting the internal electrode metal layer is preferably aluminum.

[0045] In one embodiment, the internal electrode metal layers may each have a deposition resistance value of 25 to 45 Ω / □, preferably 30 to 40 Ω / □ or 32 to 38 Ω / □, and more preferably 34 to 36 Ω / □. This makes it possible to provide a thin-film polymer laminated capacitor element with sufficient breakdown voltage without setting the resistance value excessively high. In the case of a heavy edge, the deposition resistance value of the internal electrode metal layer may be the value measured in the metal region other than the heavy edge.

[0046] Generally, reducing the metal deposition resistance can be considered in order to increase the current, but in this case, sufficient performance may not be obtained, especially when a high withstand voltage is desired. In contrast, in the above-described embodiment of the present invention, particularly good withstand voltage is ensured by limiting the deposition resistance value of the internal electrode metal layer to a specific value.

[0047] (Heavy Edge) In one embodiment, the internal electrode metal layer has a thickness greater than the thickness of the internal electrode metal layer outside the edge region at the end region on the external electrode side, thereby forming a heavy edge (see Figure 2). This makes it easier to obtain the desired capacitance, as well as good connectivity with the external electrode and good dielectric strength.

[0048] In one embodiment, the heavy edge may have a deposition resistance value of 1 to 30 Ω / □, preferably 2 to 20 Ω / □, and more preferably 3 to 10 Ω / □. The deposition resistance value can be measured by a surface resistance meter using the four-terminal method.

[0049] The heavy edge may be formed by increasing the thickness in the stacking direction of a portion of the metal region located on the edge side (external electrode side) of the internal electrode metal layer, or it may be formed from at least two metal regions, that is, for example, by depositing a second metal region on top of a first metal region.

[0050] In one embodiment, the internal electrode metal layer may have a thickness of 1 nm to 100 nm, preferably 2 to 20 nm.

[0051] <Laminate> A laminate is formed by alternately stacking multiple dielectric layers and multiple internal electrode metal layers.

[0052] In one embodiment, the laminate has a thickness of 1.0 to 3.0 mm, preferably 1.2 to 2.7 mm, and more preferably 1.5 to 2.5 mm.

[0053] The thin-film polymer laminated capacitor element according to the present invention may have 1,000 to 8,000 layers, 1,200 to 6,000 layers, or 1,500 to 4,000 layers, for example, by counting one dielectric layer and one internal electrode metal layer as one set, or "one layer". This number of layers may particularly relate to the number of dielectric layers and internal electrode metal layers in the laminated portion of the capacitor that contributes to the capacitor function (for example, the reinforcing portion and the protective portion may be excluded from the calculation).

[0054] The capacitor element of the present invention can be used alone as a capacitor, or a plurality of them can be deposited to form a block body. Further, a plurality of block bodies can be laminated to form a module body.

[0055] <External electrodes> The external electrodes are formed at both ends in the length direction of the laminate.

[0056] As an example, the external electrode has a first external electrode layer formed by spraying a metal and a second external electrode layer formed by plating a metal. According to this configuration, a configuration excellent in solder connection performance can be easily realized during mounting. As an example, for the first external electrode layer, brass, zinc, aluminum, or other known sprayed metals can be applied. As an example, for the second external electrode layer, copper, tin, gold, silver, or other known plated metals can be applied.

[0057] <Dimensions> The thin-film polymer laminated capacitor element according to the present invention may have a height H of 1.0 to 3.0 mm, preferably 1.2 to 2.7 mm, more preferably 1.3 to 2.5 mm, a length L of 8 to 71 mm, preferably 8 to 60.2 m, more preferably 8 to 54.8 mm, and / or a width W of 5 to 100 mm, preferably 5 to 70 mm, more preferably 8 to 70 mm.

[0058] Also, the thin-film polymer laminated capacitor element 10 according to the present invention has an area S (length L × width W) of 40 to 7100 mm ２ , preferably 40 to 6020 mm ２ , more preferably 40 to 5480 mm ２ and may have a volume V (height H × length L × width W) of 40 to 21300 mm ３ , preferably 40 to 18060 mm ３ , more preferably 40 to 16440 mm ３ and may be.

[0059] In one aspect, the thin-film polymer laminated capacitor element according to the present invention may have a volume per unit energy (J) of 1.0 to 3.2 cm ３ , preferably 1.1 to 2.8 cm ３ , more preferably 1.3 to 2.1 cm ３ and may have.

[0060] <Electrical Characteristics> (Dielectric Breakdown Voltage (Allowable Voltage Gradient)) In one embodiment, the thin-film polymer laminated capacitor element according to the present invention has a dielectric breakdown voltage (BDV) of 400 V / μm or more, preferably 600 V / μm or more. The upper limit is not particularly limited, but may be, for example, 800 V / μm or less. The dielectric breakdown voltage (BDV) can be measured using a voltage withstand tester, by applying a voltage at a constant boost rate, and the voltage when it exceeds a certain threshold current may be taken as the BDV value. Typically, the boost rate is 10 to 50 V / sec, and the threshold current is 1 to 10 mA. In this application, measurement can be performed with a boost rate of 25 V / sec and a threshold current of 5 mA.

[0061] (Allowable Ripple Current) In one embodiment, the thin-film polymer laminated capacitor element according to the present invention has an allowable unit ripple current of 0.4 Arms / μF or more, preferably 1.0 Arms / μF or more, at 10 kHz. The upper limit is not particularly limited, but may be, for example, 2.0 Arms / μm or less. The allowable ripple current can be measured by a ripple heating test consisting of a high-frequency high-current power supply and capacitor temperature measurement, and by confirming the current value that reaches the allowable heating temperature.

[0062] (Capacitance) In one embodiment, the thin-film polymer laminated capacitor element according to the present invention has a capacitance of 1 to 30 μF, or more specifically, 1 to 15 μF.

[0063] <Block Module> Multiple thin-film polymer laminated capacitor elements according to the present invention may be stacked (for example, 2 to 30, or even 3 to 20) to form a block structure, and further, multiple such block structures (for example, 2 to 20) may be welded to a busbar to form a module structure. In this case, the capacitance of the block structure (block capacitance) may be 3 to 200 μF, or even 5 to 100 μF, and the capacitance of the module structure (module capacitance) may be 10 to 2000 μF, or even 20 to 1000 μF. Furthermore, the module structure (excluding the module casing) may be 2000 cm². ３ The following, or even 1 to 1500 cm ３ It may have the volume of [this].

[0064] (Relative Permittivity) Preferably, the thin-film polymer laminated capacitor element has a relative permittivity of 2.0 or higher when measured at 25°C and 1 kHz. More preferably, this relative permittivity is 2.1 or higher, 2.2 or higher, 2.3 or higher, or 2.5 or higher. There is no particular upper limit to this relative permittivity, but it may be 5.0 or lower.

[0065] The relative permittivity at 25°C and 1 kHz can be calculated based on the capacitance measured using an LCR meter, as well as the electrode area and dielectric thickness.

[0066] (tanδ) Preferably, the thin-film polymer laminated capacitor element has a tanδ (also called dielectric loss tangent or loss coefficient) of less than 1.0% when measured at 25°C and 1 kHz. More preferably, this tanδ is 0.9% or less, 0.85% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, or 0.1% or less. The lower limit of this tanδ is not particularly limited, but may be 0.05% or more.

[0067] The tanδ at 25°C and 1 kHz can be measured using an LCR meter.

[0068] Furthermore, preferably, the thin-film polymer laminated capacitor element has a tanδ of less than 2.0% when measured at 105°C and 1 kHz. More preferably, this tanδ is 1.5% or less, and even more preferably 1.2% or less. The lower limit of this tanδ is not particularly limited, but may be 0.1% or more.

[0069] The tanδ at 105°C and 1 kHz can be measured using an LCR meter.

[0070] <Applications of thin-film polymer multilayer capacitor elements>

[0071] In one embodiment of the present invention, the thin-film polymer laminated capacitor element according to the present invention may be for automotive inverter circuits and / or solar power inverter circuits.

[0072] In one embodiment of the present invention, the thin-film polymer laminated capacitor element according to the present invention can be used at a voltage of 400 to 1200 VDC.

[0073] Furthermore, this disclosure includes the following aspects of the invention: a thin-film polymer laminated capacitor element having a laminate in which a plurality of dielectric layers and a plurality of internal electrode metal layers are alternately stacked, and external electrodes formed at both ends in the longitudinal direction of the laminate, for use in applications involving voltages of 400 to 1200 VDC, wherein each internal electrode metal layer has a plurality of metal regions separated by a margin portion, and the respective metal regions of two adjacent internal electrode metal layers separated by a dielectric layer are offset in the longitudinal direction of the laminate, thereby forming an internal series structure having a plurality of capacitance appearance portions, and each metal region forming the internal series structure has an active length of 1.8 mm to 5.2 mm along the longitudinal direction.

[0074] A thin-film polymer laminated capacitor element according to a particularly preferred embodiment of the present invention comprises: a laminate formed by alternately stacking a plurality of dielectric layers and a plurality of internal electrode metal layers, and a pair of external electrodes formed at both ends in the longitudinal direction of the laminate, wherein each of the internal electrode metal layers has a plurality of metal regions separated by a margin portion, and the respective metal regions of two adjacent internal electrode metal layers separated by a dielectric layer are offset in the longitudinal direction of the laminate, thereby forming an internal series structure having a plurality of capacitance appearance portions, wherein the plurality of dielectric layers have a thickness of 0.4 to 0.8 μm, the plurality of internal electrode metal layers have a deposition resistance value of 25 to 45 Ω / □, and the metal regions forming the internal series structure have an active length of 1.8 mm to 5.2 mm along the longitudinal direction.

[0075] Details of each component in this particularly preferred embodiment, especially the thickness of the dielectric layer, the deposition resistance of the internal electrode metal layer, and the active length (for example, preferred ranges of values), can be found in the above-mentioned descriptions relating to each of these parameters.

[0076] In this particularly preferred embodiment, in addition to the active length, the thickness of the dielectric layer and the deposition resistance of the internal electrode metal layer are all limited to specific ranges. In this case, better characteristics can be achieved than when only the active length satisfies the above range conditions, or when only the active length and any of the above parameters satisfy the above range conditions.

[0077] To achieve significant miniaturization, higher voltage resistance, and higher current capacity, as well as stable productivity suitable for mass production, a delicate balance of numerous configuration parameters is crucial. In this regard, the thin-film polymer laminated capacitor element according to the present invention has optimized dielectric thickness, deposition resistance, and active length, and this specific combination makes it possible to simultaneously and significantly improve miniaturization, high voltage resistance, high current resistance, and productivity.

[0078] More specifically, by having the thickness of the multiple dielectric layers constituting the laminate be within the range of 0.4 to 0.8 μm, good connectivity between the internal and external electrodes is achieved, further optimizing the ESR and resulting in a sufficiently miniaturized thin-film polymer laminated capacitor element. Furthermore, having the dielectric layer thickness within this range favorably suppresses the increase in tanδ (the effect of suppressing the increase in tanδ becomes particularly pronounced at a film thickness of 0.4 μm). Moreover, stable production is realized. Although there is no intention to limit it by theory, if the film thickness is 0.8 μm or less, it is conceivable that the reduction in the anchoring effect of the thermal spray metal can be avoided or suppressed, so the adhesion strength of the external electrodes to the element body is maintained particularly well, and the increase in tanδ and ESR can be suppressed.

[0079] Furthermore, by having the deposition resistance of the internal electrode layer forming the laminate be in the range of 25 to 45 Ω / □, the desired sufficient high-voltage resistance can be achieved, and undesirable effects that may occur when the deposition resistance is excessively high (e.g., excessive heat generation of the thin-film polymer laminated capacitor element, increase in tanδ) can be avoided. In addition, by reducing the heat generation of the thin-film polymer laminated capacitor element, it is possible to improve the allowable ripple current. In particular, when the deposition resistance is 25 Ω / □ or higher, an excellent withstand voltage value (400 V / μm) can be secured. Also, when the deposition resistance is 45 Ω / □ or lower, it is particularly desirable because the increase in tanδ is well suppressed.

[0080] Regarding the active length, as mentioned above, by setting the active length of the internal series structure to be relatively small (5.2 mm or less), the capacitance per layer is suppressed for a given capacitance, and it is thought that the number of layers can be increased relatively. As the number of layers increases, the metal ratio in the same volume increases, so it is presumed that the ESR is reduced, and thereby the heat generated when ripple current flows is reduced. Furthermore, by setting the active length of the internal series structure to be within a range that is not excessively small (1.8 mm or more), it is presumed that the thin-film polymer multilayer capacitor element can be miniaturized without the number of layers becoming excessively large, and without the margin portion per internal electrode metal layer becoming excessively large.

[0081] In particular, by setting the active length within the specified range under the conditions of dielectric thickness and deposition resistance values ​​described above, it is possible to achieve significant miniaturization compared to conventional capacitors (such as PP capacitors), as well as particularly excellent current characteristics (especially suitability for large currents of 0.4 Arms / μF or more at 10 kHz).

[0082] <<Method for Manufacturing Thin-Film Polymer Multilayer Capacitor Elements>> The method for manufacturing thin-film polymer multilayer capacitor elements according to this disclosure is not particularly limited. For example, the thin-film polymer multilayer capacitor elements according to this disclosure can be manufactured by the method for manufacturing thin-film polymer multilayer capacitor elements according to this disclosure described below.

[0083] The present invention provides a method for manufacturing a thin-film polymer laminated capacitor element, comprising: (a) forming a dielectric layer; (b) applying a patterning oil to the dielectric layer and then depositing a metal to form an internal electrode metal layer having metal regions separated by a margin; and (c) continuously and alternately repeating the formation of the dielectric layer and the formation of the internal electrode metal layer in a vacuum to form a laminate, wherein in (c), an internal series structure is formed by laminating two adjacent internal electrode metal layers such that the respective metal regions of the laminate are offset in the longitudinal direction of the laminate, and each metal region forming the internal series structure has an active length of 1.8 mm to 5.2 mm along the longitudinal direction of the laminate.

[0084] By performing metal deposition so that the metal region of the internal series structure has an active length of 1.8 mm to 5.2 mm, it becomes possible to increase the current capacity and miniaturize thin-film polymer multilayer capacitor elements. Although not limited to theory, since the internal electrode metal layer is formed by depositing metal, a thin layer is formed, and therefore the ratio of the dielectric layer is relatively high, resulting in a relatively high ESR, which is thought to have caused a problem in that the heat generated when ripple current flows cannot be sufficiently suppressed. In contrast, if metal deposition is performed so that the metal region has the above-mentioned active length, miniaturization is ensured, and the ratio of metal in the same volume is also optimized by optimizing the number of layers, so the ESR is suppressed, and it is presumed that the heat generated when ripple current flows can be sufficiently suppressed.

[0085] For preferred ranges of each component (e.g., dielectric layer, internal electrode metal layer, and external electrode) and dimensions in the manufacturing method of the thin-film polymer multilayer capacitor element according to this disclosure, refer to the above description of the thin-film polymer multilayer capacitor element according to this disclosure.

[0086] <Dielectric Layer Provisioning Process> The method for manufacturing a thin-film polymer multilayer capacitor element of the present invention includes providing a dielectric layer.

[0087] The method for providing the dielectric layer is not particularly limited, but for example, the dielectric layer may be provided by depositing monomers in a vacuum chamber to form a monomer layer, and then curing the monomer layer by irradiating it with an electron beam to form the dielectric layer.

[0088] When forming a dielectric layer, for example, a dimethacrylate compound having an alicyclic hydrocarbon skeleton can be used as the monomer to form the monomer layer.

[0089] The dielectric layer is often formed using monomers having acrylic or methacrylic groups. Examples of such monomers include dicyclopentadiene methanol diacrylate, tricyclodecane dimethanol diacrylate, and tricyclodecane dimethanol dimethacrylate.

[0090] In one embodiment, the dielectric layer has a polymer structure obtained by polymerizing a first monomer which is a monofunctional monomer, a second monomer which is a difunctional monomer, and a third monomer which is a trifunctional or polyfunctional monomer. For example, the first monomer may include 2-(biphenyl-2-yloxy)-ethyl acrylate, 4-phenylbenzyl acrylate, stearyl acrylate, or stearyl methacrylate, the second monomer may include tricyclodecanedimethanol diacrylate or tricyclodecanedimethanol dimethacrylate, and / or the third monomer may include triallyl isocyanurate.

[0091] <Internal Electrode Metal Layer Formation Process> The method for manufacturing a thin-film polymer laminated capacitor element of the present invention includes applying a patterning oil onto a dielectric layer and then depositing a metal to form an internal electrode metal layer having a metal region separated by a margin.

[0092] The application of patterning oil and the deposition of metal can be carried out, for example, using a patterning oil apparatus and a metal deposition apparatus, according to known methods.

[0093] Examples of metallic materials for forming the internal electrode metal layer include at least one selected from the group consisting of aluminum (Al), copper (Cu), zinc (Zn), tin (Sn), gold (Au), silver (Ag), and platinum (Pt), as well as combinations thereof.

[0094] (Heavy edge formation method) In one embodiment, in step (b), a heavy edge may be formed in the region of the internal electrode metal layer that will become the edge when the thin-film polymer multilayer capacitor element is completed. This makes it possible to provide a thin-film polymer multilayer capacitor element that has the desired capacitance, as well as good connectivity with the external electrode and good voltage withstand characteristics.

[0095] The method for forming a heavy edge is not particularly limited, but for example, a heavy edge may be formed by forming a thicker internal electrode metal layer in the region on the external electrode side of the internal electrode metal layer of the internal electrode metal layer than the internal electrode metal layer in other regions of the internal electrode metal layer as a thin-film polymer multilayer capacitor element. As another example, a heavy edge may be formed by depositing a metal material onto the edge region and then depositing the same metal material or a different metal material onto the edge region.

[0096] <Laminate Provisioning Process> The manufacturing method of the thin-film polymer laminated capacitor element of the present invention includes forming a laminate by continuously and alternately repeating the formation of a dielectric layer and the formation of an internal electrode metal layer in a vacuum (for example, in a vacuum chamber). In forming this laminate, an internal series structure is formed by stacking two adjacent internal electrode metal layers such that their respective metal regions are offset in the longitudinal direction of the laminate, and each metal region forming the internal series structure has an active length of 1.8 mm to 5.2 mm along the longitudinal direction of the laminate. This makes it possible to provide a thin-film polymer laminated capacitor element that achieves miniaturization and high current capacity well.

[0097] The lamination method is not particularly limited, but for example, a laminated matrix in which dielectric layers and internal electrode metal layers are alternately laminated on a rotating drum may be provided by alternately forming dielectric layers and internal electrode metal layers on a rotating drum in a vacuum chamber. For example, see International Publication No. 2015 / 118693.

[0098] (External electrode formation process) The obtained laminated matrix can be cut into, for example, a stick shape, then external electrodes can be formed, and these can be further cut into a chip shape to obtain a thin-film polymer laminated film capacitor.

[0099] Thin-film polymer laminated film capacitors may be assembled into blocks or modules. In this case, the resulting laminated matrix is ​​cut into stick shapes, external electrodes are formed on the end faces perpendicular to the width direction, and then cut into chip shapes. Next, a block may be formed using multiple cut laminated matrix pieces, and a module may be formed by welding them to a busbar.

[0100] The method for forming the external electrodes is not particularly limited, but for example, external electrodes may be formed on one end and the other end of the laminate using a metallic material.

[0101] In one embodiment, the external electrode may be formed by first forming a first external electrode layer by spraying a metal material using a known metal spraying apparatus, and then forming a second external electrode layer by further plating with another metal material using a known plating apparatus. This method makes it easy to realize a configuration with excellent solder connection performance. As an example, the first external electrode layer can be made of brass, zinc, aluminum, or other known sprayable metals. As an example, the second external electrode layer can be made of copper, tin, gold, silver, or other known plated metals.

[0102] <<Examples 1-7 and Comparative Examples 1-7>> In Examples 1-7 and Comparative Examples 1-7, thin-film polymer multilayer capacitor elements were fabricated, and modules were fabricated using these elements to evaluate their physical properties.

[0103] <Example 1> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Example 1 are summarized in Table 1.

[0104] The procedure for fabricating the thin-film polymer multilayer capacitor element module according to Example 1 includes the following: (1) Oil is applied to a dielectric layer formed using tricyclodecanedimethanol diacrylate as a monomer at a pitch of 4.8 mm using a patterning apparatus, aluminum is deposited, and then zinc is deposited on the end region on the outer region side to form an internal electrode metal layer having a heavy edge. (2) The formation of the dielectric layer and the formation of the internal electrode metal layer are alternately repeated on a rotating drum placed in a vacuum to form a laminate, and then an external electrode is formed on the end face perpendicular to the width direction to obtain a thin-film polymer multilayer capacitor element. At this time, the lamination is carried out so that the multiple internal electrode metal layers have an internal series structure and the active length is 2.0 mm. The metal used to form the external electrode is zinc aluminum. (3) Twenty of the above thin-film polymer multilayer capacitor elements are stacked in the stacking direction (height direction H). (3) Two of the above thin-film polymer multilayer capacitor elements are stacked and then joined together by spraying Sn metallicon (tin zinc) onto both sides of the surface perpendicular to the length direction of the stacked 20 thin-film polymer multilayer capacitor elements to form a block of thin-film polymer multilayer capacitor elements.

[0105] (Measurement of Allowable Ripple) The allowable ripple (Arms) was determined by superimposing a 10 kHz high-frequency current from the power supply to the capacitor, assuming an allowable heat generation temperature of 40°C, measuring the surface temperature of the capacitor element with a thermocouple, and defining the current value at which the allowable heat generation temperature was reached as the allowable ripple current value.

[0106] (Dimensions) Dimensions were measured by observation using an optical microscope or by measurement using calipers.

[0107] (Evaporation Resistance) The evaporation resistance was measured using a surface resistance meter with a four-terminal method.

[0108] <Example 2> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Example 2 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 6.0 mm, the active length is 2.6 mm, the number of layers is 1950, the element H dimension is 1.47 mm, the element L dimension is 12.8 mm, and the number of block elements is 15.

[0109] <Example 3> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Example 3 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 6.8 mm, the active length is 3.0 mm, the number of layers is 1950, the element H dimension is 1.47 mm, the element L dimension is 14.4 mm, and the number of block elements is 13.

[0110] <Example 4> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Example 4 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 8.0 mm, the active length is 3.6 mm, the number of layers is 1920, the element H dimension is 1.45 mm, the element L dimension is 16.8 mm, and the number of block elements is 11.

[0111] <Example 5> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Example 5 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 8.8 mm, the active length is 4.0 mm, the number of layers is 1900, the element H dimension is 1.44 mm, the element L dimension is 18.4 mm, and the number of block elements is 10.

[0112] <Example 6> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Example 6 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 10.0 mm, the active length is 4.6 mm, the number of layers is 1840, the element H dimension is 1.39 mm, the element L dimension is 20.8 mm, and the number of block elements is 9.

[0113] <Example 7> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Example 7 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 10.8 mm, the active length is 5.0 mm, the number of layers is 1900, the element H dimension is 1.44 mm, the element L dimension is 22.4 mm, and the number of block elements is 8.

[0114] <Comparative Example 1> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Comparative Example 1 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 2.0 mm, the active length is 0.6 mm, the number of layers is 1920, the element H dimension is 1.45 mm, the element L dimension is 4.8 mm, and the number of block elements is 66.

[0115] <Comparative Example 2> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Comparative Example 2 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 2.8 mm, the active length is 1.0 mm, the number of layers is 1900, the element H dimension is 1.44 mm, the element L dimension is 6.4 mm, and the number of block elements is 40.

[0116] <Comparative Example 3> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Comparative Example 3 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 4.0 mm, the active length is 1.6 mm, the number of layers is 1900, the element H dimension is 1.44 mm, the element L dimension is 8.8 mm, and the number of block elements is 25.

[0117] <Comparative Example 4> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Comparative Example 4 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 12.0 mm, the active length is 5.6 mm, the number of layers is 1940, the element H dimension is 1.46 mm, the element L dimension is 24.8 mm, and the number of block elements is 7.

[0118] <Comparative Example 5> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Comparative Example 5 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 12.8 mm, the active length is 6.0 mm, the number of layers is 1810, the element H dimension is 1.37 mm, the element L dimension is 26.4 mm, and the number of block elements is 7.

[0119] <Comparative Example 6> The specifications of the thin-film polymer multilayer capacitor element module according to Comparative Example 6 are the same as those of the thin-film polymer multilayer capacitor element module according to Example 1, except that the oil nozzle pitch is 14.0 mm, the active length is 6.6 mm, the number of layers is 1920, the element H dimension is 1.45 mm, the element L dimension is 28.8 mm, and the number of block elements is 6.

[0120] <Comparative Example 7> The specifications of the thin-film polymer multilayer capacitor element module fabricated in Comparative Example 7 are the same as those of the thin-film polymer multilayer capacitor element module in Example 1, except that the oil nozzle pitch is 14.8 mm, the active length is 7.0 mm, the number of layers is 1810, the element H dimension is 1.37 mm, the element L dimension is 30.4 mm, and the number of block elements is 6.

[0121] <Evaluation Results> Figure 3 shows the results of the allowable ripple current measurement at 10 kHz and the relationship between the module volume and the active length for Examples 1 to 7 (E1 to E7) and Comparative Examples 1 to 7 (C1 to C7) of module bodies formed using the thin-film polymer multilayer capacitor element according to the present invention.

[0122] In Figure 3, Examples 1 to 7 (E1 to E7) are shown to have a relatively large allowable ripple current while being contained in a relatively small volume. Specifically, under the conditions of 500V and 100μF, 32cc (32cm³) ３ It has been shown that the device fits within a volume of ) or less and has an allowable ripple current of 40 Arms or more at a switching frequency of 10 kHz. On the other hand, Comparative Examples 1 to 3 (C1 to C3), which have a shorter active length than the example, have a larger volume than the example, and Comparative Examples 4 to 7 (C4 to C7), which have a longer active length than the example, have a smaller allowable ripple current than the example.

[0123] In particular, the module bodies of the examples (E1 to E7) employ a deposition resistance of 35Ω / □ for the internal electrode metal layer. This ensures high current capacity while maintaining sufficient dielectric strength (dielectric breakdown voltage: approximately 500V / μm) by avoiding excessively high resistance.

[0124] 10a, 10b, 20 Thin-film polymer laminated capacitor element 101a, 101b, 201 Dielectric layer 102a, 102b, 202 Internal electrode metal layer 103a, 103b, 203 External electrode 104a, 104b, 204 Laminate 105a, 105b, 205 Margin portion 106a, 106b, 206 Metal region 107a, 107b, 207 Capacitance emergence portion 208 Edge region 209 Heavy edge H Height direction (lamination direction) W Width direction L Length direction

Claims

1. A thin-film polymer laminated capacitor element having a laminate formed by alternately stacking a plurality of dielectric layers and a plurality of internal electrode metal layers, and a pair of external electrodes formed at both ends in the longitudinal direction of the laminate, wherein each of the internal electrode metal layers has a plurality of metal regions separated by a margin portion, and the respective metal regions of two adjacent internal electrode metal layers separated by the dielectric layer are offset in the longitudinal direction of the laminate, thereby forming an internal series structure having a plurality of capacitance appearance portions, and the metal regions forming the internal series structure have an active length of 1.8 mm to 5.2 mm along the longitudinal direction.

2. The thin-film polymer laminated capacitor element according to claim 1, wherein each of the plurality of dielectric layers has a thickness of 0.4 to 0.8 μm.

3. The thin-film polymer laminated capacitor element according to claim 1 or 2, wherein each of the plurality of internal electrode metal layers has a deposition resistance value of 25 to 45 Ω / □.

4. The thin-film polymer laminated capacitor element according to claim 1 or 2, wherein the dielectric layer comprises a polymer of a monomer having an acrylic group or a methacrylic group.

5. The thin-film polymer laminated capacitor element according to claim 1 or 2, wherein the number of internal series connections in the internal series structure is 2 to 12.

6. The thin-film polymer laminated capacitor element according to claim 1 or 2, wherein the metal region of the internal electrode metal layer forms a heavy edge at the end region on the external electrode side.

7. A thin-film polymer multilayer capacitor element according to claim 1 or 2, having a dielectric breakdown voltage (BDV) of 400 V / μm or more.

8. A thin-film polymer multilayer capacitor element according to claim 1 or 2, having an allowable ripple current of 0.4 Arms / μF or more.

9. The volume per unit energy (J) is 1.0 to 3.2 cm³. ３ The thin-film polymer laminated capacitor element according to claim 8, having and / or having 1,000 to 8,000 layers, with one dielectric layer and one internal electrode metal layer forming one layer.

10. A thin-film polymer multilayer capacitor element according to claim 1 or 2, for use with a voltage of 400 to 1200 VDC.

11. A method for manufacturing a thin-film polymer multilayer capacitor element, comprising: (a) forming a dielectric layer; (b) applying a patterning oil to the dielectric layer and then depositing a metal to form an internal electrode metal layer having a metal region separated by a margin; and (c) continuously and alternately repeating the formation of the dielectric layer and the formation of the internal electrode metal layer in a vacuum to form a laminate, wherein in (c), an internal series structure is formed by stacking two adjacent internal electrode metal layers such that the respective metal regions are offset in the longitudinal direction of the laminate, and the metal regions forming the internal series structure have an active length of 1.8 mm to 5.2 mm along the longitudinal direction of the laminate.

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