Showing papers on "Tantalum capacitor published in 2018"

Investigation of thermal effects and lifetime estimation of electrolytic double layer capacitors during repeated charge and discharge cycles in dedicated application

Abstract: The article is firstly focused on thermal analysis of electrolytic double layer capacitor (EDLC) operated at repeated cycles of charging and discharging. This process is mostly applied at switched mode power supplies (SMPS), where electrolytic capacitor within given period of operation acts as energy storage element (discharge period). Charging and discharging process of EDLC may cause additional heating, which consequently influences capacitor’s lifetime. This parameter (lifetime) is nowadays very important parameter of EDLC, because operational life of the most of complex power electronic systems is directly influenced by its most critical components, i.e., by electrolytic capacitors. In this paper, the theory necessary for capacitor analysis and analysis of heat transfer is presented. The particular aluminum electrolytic capacitor Nichicon is examined in the paper. The implementation of real model into COMSOL Multiphysics and consequent simulation settings are being described too. Based on the main parameters of target application, the simulation analysis is processed. These results are consequently verified by experimental measurements on a given sample of EDLC. Deviations between measured and simulated data are identified, and optimization steps for better accuracy are also given. Finally, the factors influencing the lifetime of electrolytic capacitors together with calculation of capacitor’s lifetime in power application are described. During lifetime estimation, heat transfer simulation modeling of capacitor is utilized. Presented approach offers acceleration of necessary variables identification, which are hardly to be identified with the use of measurements, e.g., capacitor’s core temperature. Thus, more accurate results regarding lifetime estimation can be achieved.

Ultra-High Density, Thin-Film Tantalum Capacitors with Improved Frequency Characteristics for MHz Switching Power Converters

Abstract: High-density passive components are needed for continued miniaturization of complex high-performance electronic systems. Tantalum (Ta) capacitors provide some of the highest volumetric densities achieved due to their combination of high-surface area and relatively high dielectric constant, but suffer from low frequency stability and large form-factors due to the electrode design. In this paper, a printed thin-film tantalum capacitor design is presented. Tantalum capacitor arrays of 1 μF/mm2 up to and beyond 1 MHz. The improved frequency stability comes from the ultra-thin structure of the capacitors, which reduces the path length of the charging and discharging current. The capacitors showed low equivalent series resistance and consistent electrical performance before and after thermal moisture testing at 65°C and 95% relative humidity for 500 h and 1000 h. Due to the ultra-low form-factor, the thin-film Ta capacitor technology can be extended to highly-miniaturized power converters with efficient substrate- or wafer-scale integration.

Anomalous Transients in Chip Polymer Tantalum Capacitors

Abstract: Contrary to MnO2 tantalum capacitors, transient processes in polymer tantalum capacitors after voltage application might result in anomalously high, ampere-level currents when a capacitor might appear as a short circuit for a time that is much greater than a transient time in MnO2 capacitors. In this work, conditions that cause anomalous transients in different types of polymer tantalum capacitors have been analyzed. Related phenomena that included increasing of capacitance and dissipation factors with voltage, parametric surge current test failures without damage to capacitors, and increasing leakage currents at low temperatures are described. It has been shown that anomalous transients increased substantially with applied voltage and with reduction of moisture content in capacitors caused by storage or operation at high temperatures and/or in vacuum. Different types of capacitors exhibited different level of transients and modification of conductive polymers or process of their application might decrease transient leakage currents substantially. For space applications, the risk of failures related to anomalous transients can be mitigated by special testing procedures to select parts with an acceptable level of transients and by voltage derating.

Back-end production detection process and production line of tantalum capacitors

Abstract: The invention provides a back-end production detection process and a production line of tantalum capacitors, which can realize the circulation of tantalum capacitors between different test devices, and can achieve convenient and quick circulation, improve the production efficiency, and reduce the labor cost. The production line includes a strip-shaped tantalum capacitor tester, a capacitor shaper,a shape screening machine, and a capacitor auto-loader which are sequentially arranged; the auto-loader includes a circulation plate; capacitor fixing grooves capable of accommodating the capacitorsare distributed on the circulation plate; a single tantalum capacitor screened by the shape screening machine is mounted in the capacitor fixing groove of the circulation plate; the circulation platecirculates among a front-end aging fixture contact test machine, an aging box, a back-end aging fixture contact test machine, a tantalum capacitor high-low temperature surge machine, a high-low temperature 4 parameter test machine, and a normal temperature 4 parameter test machine.

Major Degradation Mechanisms

Abstract: The basic bilayer of all types of tantalum capacitors, tantalum anode, and anodic oxide film of tantalum as a dielectric is not a thermodynamically stable system. This is demonstrated by the tantalum-oxygen equilibrium diagram that does not contain two-phase equilibrium areas for pure tantalum and tantalum pentoxide]. Relaxation of the Ta-Ta2O5 system into the thermodynamically stable state occurs through oxygen migration from Ta2O5 to Ta, resulting in oxygen vacancies in the tantalum oxide dielectric. Conductivity of the dielectric and, thereby, DCL of tantalum capacitor increase exponentially with the concentration x of oxygen vacancies in the depleted with oxygen Ta2O5–x. Another reason for the thermodynamic instability of tantalum capacitors is the amorphous structure of the anodic oxide film of tantalum formed on crystalline tantalum. Amorphous dielectrics trend to ordering and crystallization spontaneously to reduce their internal energy. Growth of crystalline inclusions in amorphous matrix of the anodic oxide film induces mechanical stress in the film, which results in a disruption of the dielectric and, thereby, in the failure of the capacitor.

Anode tantalum block and preparation method thereof

Abstract: The invention relates to an anode tantalum block and a preparation method thereof. The anode tantalum block comprises a column-shaped tantalum block body. A side wall of the column-shaped tantalum block body is provided with multiple grooves with equal intervals along a radial direction, each groove passes through two ends of the tantalum block body along an axial direction, the depth of each of the grooves is 5% to 80% of the radius of the tantalum block body, and the ESR value of a non-solid electrolyte tantalum capacitor is reduced. The preparation method of the anode tantalum block comprises the steps of pressing tantalum powder to form a green body of the anode tantalum block and carrying out vacuum sintering. The anode tantalum block which effectively reduces the ESR value of the non-solid electrolyte tantalum capacitor is prepared, and the industrial production is facilitated at the same time.

Abnormal Capacitance Increasing at Elevated Temperature in Tantalum Capacitors with PEDOT:PSS Electrodes

Abstract: Due to the importance of capacitance temperature stability in precise analog circuit applications, capacitance instability at elevated temperature of 125°C was investigated in tantalum capacitors with PEDOT:PSS counter electrodes. Capacitance-voltage measurement supposed that residual ions in the PEDOT:PSS dispersion caused an accumulation of charges at the dielectric-cathode interface which contributed to an increase in the dielectric constant and resulted in the capacitance increasing at high temperature. Based on the hypothesis, water wash process was applied and capacitance dropped significantly at high temperature. This study shows that an additional water wash process is necessary to improve the capacitance temperature stability after each dispersion dip step.

Molded packaging liquid tantalum capacitor capable of surface mounting

Abstract: The invention discloses a molded packaging liquid tantalum capacitor capable of surface mounting. The molded packaging liquid tantalum capacitor comprises a tantalum core, a metal shell and a molded packaging layer, wherein the metal shell is arranged outside the tantalum, the molded packaging layer is arranged outside the shell, the tantalum core is connected with a positive lead frame via the tantalum core, the positive lead frame is arranged at one end of the exterior of the molded packaging layer, a negative lead frame is arranged at the other end of the exterior of the molded packaging layer, a gap exists between the shell and the tantalum core, and the gap is filled with a liquid electrolyte. A traditional tantalum capacitor solid electrolyte is changed to a liquid electrode, a molded packaging mode capable of surface mounting is used, the volume of the whole tantalum capacitor can be reduced, so that the occupancy space can be reduced, a ripple current higher than those of the other types of surface-mounting capacitor can be borne, and a reverse voltage higher 3V also can be borne.

Technological method for reducing ESR of tantalum capacitor film coating process

Abstract: The invention belongs to the technical field of capacitor manufacture, particularly to a technological method for reducing the ESR of a tantalum capacitor film coating process. Processing of a tantalum core is completed through steps of impregnation, dehydration, decomposition, complementary forming, re-impregnation, re-dehydration, re-decomposition and subsequent treatment, through adjustment andcontrol of process parameters, proceeding of decomposition process is promoted, and the effective series resistance (ESR) of the tantalum capacitor is effectively improved; and in the re-decomposition process, through control of oxygen content, a phenomenon that solution splashing causes tantalum wires to be dirty is effectively prevented.

Silicon-lithium-tantalum capacitor battery

Abstract: A silicon-lithium-tantalum capacitor battery comprises a positive plate, a negative plate, electrolyte, a diaphragm connected between the positive plate and the negative plate, and a shell; all the positive plate, the negative plate, the electrolyte, the diaphragm and the electrode are hermetically arranged in the shell. The silicon-lithium-tantalum capacitor battery is characterized in that a tantalum capacitor is also arranged in the shell and is connected parallelly between the positive plate and the negative plate, the positive plate includes lithium nickel cobaltate, lithium cobalt oxideand tantalum oxide which have a mass ratio of 1:1:1; the positive plate is prepared by spraying the lithium cobalt oxide and the tantalum oxide to the surface of lithium nickel cobaltate by laser spraying; the diaphragm is a semiconductor diaphragm. Compared with traditional lithium batteries and lead-acid batteries, the silicon-lithium-tantalum capacitor battery has greatly increased energy density, greatly shortened charging time and long service life, is environmentally friendly and never causes contamination.

A ultrasonic vibration self -interacting embossing mold utensil for tantalum electric capacity press forming

Abstract: The utility model discloses an ultrasonic vibration self -interacting embossing mold utensil for tantalum electric capacity press forming to solve current tantalum electrolytic capacitor embossing mold utensil assembly complicacy and the relatively poor problem of tantalum core density uniformity and consistency. The utility model discloses a self -interacting pressure device, die cavity, piezoceramics, electrode briquetting, dress matching board, the fixing bolt six boards divide and form, the utility model discloses a design self -interacting loading system greatly reduced the complexity ofmould assembly, fit with a contraceptive ring piezoceramics at the die cavity outer wall of mould and produce high -frequency vibration based on adverse pressure electricity effect excitation die cavity, utilize supersound antifriction principle, so reduce between tantalum powder granule with tantalum powder granule and die cavity in intermural frictional force to reach the even mesh of tantalum core density distribution. In this way,

Thin film lubrication scheme in tantalum spinneret micro-pore punching process

Abstract: The invention provides a thin film lubrication method in a tantalum spinneret micro-pore punching process The thin film lubrication method is characterized by comprising the following steps: (a) machining and producing a metal tantalum plate into a tantalum spinneret; (b) generating one layer of amorphous tantalum pentoxide Ta2O5 film with a certain thickness on the surface of a tantalum spinneret blank produced by step (a) according to an existing anode oxidization method for producing a tantalum electrolytic capacitor; (c) after coating a blank of the amorphous tantalum pentoxide Ta2O5 filmwith the certain thickness, which is produced by step (b), with fluid lubricating oil, carrying out guide hole punching according to pre-designed parameters; (d) after washing the tantalum spinneretsubjected to first-time guide hole punching of step (c), carrying out anode oxidization of step (b), so as to generate one layer of the amorphous tantalum pentoxide Ta2O5 film on the surface of a spraying nozzle including a spinneret micro-pore; (e) coating the tantalum spinneret with the fluid lubricating oil after step (d), and carrying out next time of punching according to designed parameter requirements; (f) repeating the steps above; carrying out the anode oxidization to generate one layer of the proper amorphous tantalum pentoxide film before each time of punching and then adding the fluid lubricating oil until the final time of punching is finished

Method for removing adhesive in anode block of solid electrolytic capacitor

Abstract: The invention belongs to the technical field of manufacturing of electrolytic capacitors, and particularly discloses a method for removing an adhesive in an anode block of a solid electrolytic capacitor. Treatment is carried out through the following 11 steps of dissolving, spaying, drying, compression, reciprocating sifting, first elution, standing, second elution, third elution, boiling and drying in all, so that the adhesive and a solvent can be removed clean without a residue, improvement of electric performance parameters of the capacitor is facilitated, meanwhile, fine powder particles blocked in micropores and powder particles adhered to the surface of an anode blank are also burst through, the capacity extraction rate of the capacitor is improved, and the probability of crystallization when an anode is formed is reduced. According to the method, increase of the content of impurities of carbon and oxygen in the tantalum blank is effectively suppressed, the porosity in the tantalum blank is improved and the stability and the reliability of the tantalum electrolytic capacitor are improved.

High-energy tantalum capacitor easy to install

Abstract: The invention discloses a high-energy tantalum capacitor easy to install. The high-energy tantalum capacitor comprises a capacitor body and an insulation installation plate, wherein the insulation installation plate is arranged on the capacitor body and is provided with a metal reinforcement plate, the metal reinforcement plate is inserted onto and fixed on the insulation installation plate, and three studs are arranged on the metal reinforcement plate at equal distance. By the high-energy tantalum capacitor, the volume of the integral device can be greatly reduced, so that the installation space can be reduced, and the miniature development of terminal equipment is facilitated.

Tantalum capacitor including an anode lead frame having a bent portion and method of manufacturing the same

Abstract: A tantalum capacitor includes a capacitor body; a tantalum wire protruding from one surface of the capacitor body; a molded part enclosing the capacitor body and the tantalum wire; an anode lead frame connected to the tantalum wire and exposed to an outer surface of the molded part; and a cathode lead frame disposed on an outer surface of the capacitor body and exposed to the outer surface of the molded part. The anode lead frame includes a bend portion.

Surface-mounting solid tantalum capacitor without lead frame

Abstract: The invention discloses a surface-mounting solid tantalum capacitor without a lead frame The surface-mounting solid tantalum capacitor comprises a capacitor body, a tantalum core a positive electrodelead and a negative electrode lead are arranged in the capacitor body, and the tantalum core is packaged by epoxy resin outside the capacitor, and the positive electrode lead and the negative electrode lead are led out from the bottom of the capacitor body respectively A form without lead frame is adopted, so that the positive and negative leads of a tantalum capacitor are packaged downwards, the transverse size is reduced, the needed printed circuit board space is smaller, and the development of the small-sized terminal equipment is facilitated

High-rated voltage solid electrolyte tantalum capacitor anode, preparation method thereof, and solid electrolyte tantalum capacitor

Abstract: The invention relates to a high-rated voltage solid electrolyte tantalum capacitor anode, a preparation method thereof, and a solid electrolyte tantalum capacitor and belongs to the tantalum capacitortechnical field. According to the preparation method of the high-rated voltage solid electrolyte tantalum capacitor anode of the invention, a tantalum core to be formed is arranged in a formation liquid, and a power source is turned on, constant-temperature constant-current voltage boosting is performed until a voltage is formed, then temperature is increased, a constant voltage current reductionprocess is performed; the tantalum core is sequentially subjected to spray, boiling, washing, and heat treatment; and after the tantalum core is cooled, the cooled tantalum core is placed in the formation liquid, the power source is turned on, and the temperature is increased, so that complementary formation is carried out, the rated voltage of a tantalum capacitor composed of the prepared high-rate voltage solid electrolytic tantalum capacitor anode ranges from 63 to 100V. In the whole preparation process of the preparation method of the high-rated voltage solid electrolyte tantalum capacitor anode of the present invention, the crystallization or breakdown of the prepared tantalum capacitor anode when a formation voltage is high can be avoided. The preparation method of the invention canfurther reduce electricity consumption and lower production costs compared with a commonly-used method which is used for preparing a solid electrolyte tantalum capacitor anode and adopts a direct high temperature voltage-increase and voltage-constant strategy.

Method for obtaining the agglomerated tantal powder

Abstract: FIELD: technological processes.SUBSTANCE: invention refers to the production of the agglomerated condenser tantalum powder that can be used during manufacturing of various types of tantalum capacitors. Heating of the metal tantalum, its hydrogenation in the hydrogen atmosphere during the cooling process with the average rate of 5–20°C/min using sponge titanium hydride as the source of hydrogen are carried out. Mass of the cellular titanium hydride is determined from the following relationship: M=k⋅M, where M– mass of cellular titanium hydride, kg, M– mass of metallic tantalum, kg, k – empirical coefficient, which is equal to 0.15–0.6. Resulting tantalum hydride is ground, after which the powder is classified and the specified fraction of the tantalum hydride powder is extracted. Isolated fraction is dehydrogenated and agglomerated during heating in the inert gas flow up to the temperature of not more than 1,650 °C, where heating in the temperature range of 500–800 °C is carried out at the speed of 3–10 °C/min. Hydrogen, which is extracted during dehydrogenation, is absorbed by the cellular titanium hydride, which is used during hydrogenation, and it is used in the closed cycle. Resulting sinter is ground in order to obtain the agglomerated tantalum powder.EFFECT: reduction of 10–40 % in the hydrogenation time of the metal tantalum and the reduction in the carbon impurity content in the agglomerated tantalum powder up to three and one-half times is ensured.7 cl, 5 ex

Impregnated silver paste and tantalum capacitor

Abstract: The invention discloses impregnated silver paste and a tantalum capacitor. The raw materials of the impregnated silver paste comprise the following components, in mass percentage: polymer resin carriers 4% - 18%, silver powder 27% - 50%, graphite 1% - 8%, carbon black 1% - 8%, and solvent 42% - 70%. The tantalum capacitor includes a tantalum core, a graphite layer and a silver layer, wherein the graphite layer and the silver layer cover the tantalum core; the graphite layer is prepared by the impregnated graphite slurry; and the silver layer is prepared by the impregnated silver paste. In theimpregnated silver paste, the impregnated graphite slurry and the impregnated silver paste have similar organic components, good compatibility and uniform curing temperature, and a transition layer isformed between the cured silver layer and the cured layer after the impregnating and curing technology is modified, so that the interface mechanical strength is high; the adhesive force is high; thehigh temperature resisting mold pressing capacity is high; the conductive particles have good contact; and the inter-interface resistance is low. The impregnated silver paste and the preparation method thereof make the silver layer and the graphite layer to be overlapped preferably, and are low in the contact interface resistance so as to greatly reduce the ESR (Equivalent series Resistance) of atantalum capacitor.

Effect of Gamma Radiation on the electronic properties of PEDOT cathode tantalum capacitor

Abstract: Gamma radiation induces surface defects in PEDOT which could recover under electric field, where gamma ray restricts the polarization of dipole. Parameters of PEDOT tantalum capacitor in space could be stable when resting and vary less when working. Gamma ray favors the use of PEDOT cathode tantalum capacitor in space.

Plastic-packaged non-polar high molecular polymer tantalum capacitor

Abstract: The present invention discloses a plastic-packaged non-polar high molecular polymer tantalum capacitor. The capacitor comprises two tantalum cores. The outside of each tantalum core is wrapped with agraphite layer, the outside of each graphite layer is wrapped with a silver-plated layer, and the silver-plated layers are connected via a silver adhesive. The outside of the whole silver-plated layeris provided with an epoxy resin encapsulation layer, and the outside of the encapsulation layer is provided with extracted electrode piece(s). The capacitor can be applied to alternating current circuit(s) and relatively high using frequency circuit(s), the capacitor has a relatively high capacitance value and a relatively low internal resistance, and meanwhile the capacitor has relatively high safety and reliability.

Button-type package tantalum capacitor with stud

Abstract: The invention discloses a button-type package tantalum capacitor with a stud. The button-type package tantalum capacitor comprises a tantalum core, a tantalum shell and a metal elastic sheet, whereinthe tantalum core is arranged in the tantalum shell, the metal elastic sheet is connected with the tantalum core by a tantalum wire welded with the metal elastic sheet, a metal stud is arranged on thetantalum shell and is perpendicular to the tantalum shell, a fixed rack is arranged in the tantalum shell and is used for fixing the tantalum core, the tantalum shell is of a structure with an opening in an upper end, an upper end of the tantalum shell is packaged by a package plate, a sealing ring is arranged between the package plate and the tantalum shell, and the tantalum shell is filled witha liquid electrolyte. The button-type package tantalum capacitor has the advantage of small size, also has relatively high capability of resisting a ripple current and a reverse voltage and has relatively high reliability and long life cycle when used in a complicated environment.

High-energy tantalum hybrid capacitor

Abstract: The present invention discloses a high-energy tantalum hybrid capacitor. The capacitor comprises a capacitor body and a laser welding surface. The middle part of one surface of the capacitor body is provided with a perforating hole used for extracting a positive electrode of the tantalum capacitor, and the plane where the welding surface is located does not coincide with the plane where the perforating hole is located. The welding surface is a laser welding surface. According to the capacitor, a tantalum shell welding surface is changed to side welding, so that the positive electrode lead surface is smooth and flat maximally, and the height is reduced to be convenient for the installation of device(s). The tantalum shell welding surface is relatively far from the positive electrode weldingpoint, and the welding surface is largely reduced compared with the welding surface of a conventional product, so that the effect of high temperature on the positive electrode of the capacitor is greatly lowered when the welding is performed, and the original electrical properties of the device(s) can be better maintained.

Chip type tantalum capacitor

Abstract: The invention provides a chip type tantalum capacitor. The chip type tantalum capacitor comprises a plurality of ceramic medium diaphragms, wherein the plurality of ceramic medium diaphragms are sequentially stacked and staggered to form a tantalum chip; a layer of adhering conductive glue is coated to the exterior of the tantalum chip; a metal outer casing is coated to the exterior of the adhering conductive glue; a nickel tape is arranged at the lower end of the tantalum chip, fixedly welded on the tantalum chip, adhered into the metal outer casing by adhering silver paste, and communicatedwith a cathode leading-out end which is fixedly arranged on the metal outer casing. The chip type tantalum capacitor has the advantages that by additionally arranging the nickel tape between an anodetantalum core and the adhering silver paste, the nickel tape is used for releasing the temperature stress produced by the tantalum core, so that the high temperature-resistant ability of the capacitoris improved, and the problem of failure to meet the high-temperature working environment in the existing capacitor is solved; a new leading-out metal wire is led out and welded from an anode tantalumwire of a core block, so that the fusion welding is facilitated.

Development of High Temperature Tantalum Polymer Capacitors

Abstract: This paper focuses on the development of new 150°C capable surface mount polymer tantalum capacitors and the enabling technologies. The conductivity stability of the conducting polymers at...

Solid tantalum capacitor with extremely low ESR value and leading-out welding sheet at gold plating end

Abstract: The invention discloses a solid tantalum capacitor with an extremely low ESR value and a leading-out welding sheet at a gold plating end. The solid tantalum capacitor comprises a tantalum core and a tantalum wire, wherein an epoxy resin encapsulation layer wraps the tantalum core, a positive electrode gold plating cap and a negative electrode gold plating cap are respectively arranged at two endsof the encapsulation layer, the negative electrode gold plating cap is arranged at an opening end of the encapsulation layer, and the negative electrode gold plating cap and the tantalum core are connected by a surface welding mode. Spot welding between an existing wire and the tantalum wire is changed to contact surface welding, and the ESR value of the tantalum capacitor can be effectively reduced by large-area welding; and moreover, existing positive/negative pole plate tin plating is changed to gold plating cap leading out, the conductivity of a welding position can be greatly improved, and the contact resistance of the tantalum capacitor on a circuit board also can be greatly reduced.

Preparation method of stable and reliable chip tantalum capacitor

Abstract: The invention belongs to the technical field of electrolytic capacitor manufacturing, and particularly provides a preparation method of a stable and reliable chip tantalum capacitor. The stable and reliable chip tantalum capacitor is completed through nine steps of anode preparation, chemical formation, shielding, nitrogen treatment, post formation, adhesive layer formation, formation of the polymer electrolytic layer, post treatment and cooling and packaging. The film formation quality of the dielectric oxide film and the polymer film layer and the bonding strength between the interfaces canbe effectively improved, the problem of substantial increasing of electrostatic capacity in the high temperature or thermal shock test of the high-voltage and super-capacity organic solid electrolytechip tantalum capacitor and the problem of gradual out-of-tolerance of the leakage current along with time can be solved and the stability and the reliability of the tantalum electrolytic capacitor can be enhanced.