WO2005101972A2 - Integral separator for electrolytic capacitors - Google Patents

Integral separator for electrolytic capacitors Download PDF

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Publication number
WO2005101972A2
WO2005101972A2 PCT/IL2005/000412 IL2005000412W WO2005101972A2 WO 2005101972 A2 WO2005101972 A2 WO 2005101972A2 IL 2005000412 W IL2005000412 W IL 2005000412W WO 2005101972 A2 WO2005101972 A2 WO 2005101972A2
Authority
WO
WIPO (PCT)
Prior art keywords
valve metal
cathode
metal oxide
anode
layer
Prior art date
Application number
PCT/IL2005/000412
Other languages
English (en)
French (fr)
Other versions
WO2005101972A3 (en
Inventor
Yuri Zarnitsky
Leonid Bregman
Original Assignee
Acktar Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Acktar Ltd filed Critical Acktar Ltd
Priority to JP2007509057A priority Critical patent/JP4739326B2/ja
Publication of WO2005101972A2 publication Critical patent/WO2005101972A2/en
Publication of WO2005101972A3 publication Critical patent/WO2005101972A3/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/0029—Processes of manufacture
    • H01G9/0032—Processes of manufacture formation of the dielectric layer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/02—Diaphragms; Separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/04—Electrodes or formation of dielectric layers thereon
    • H01G9/042—Electrodes or formation of dielectric layers thereon characterised by the material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/004—Details
    • H01G9/07—Dielectric layers

Definitions

  • the present invention relates to electrolytic capacitors and their manufacture.
  • their structure contains as a rule a porous element, which, while separating the plates, simultaneously allows movement of current carriers therethrough.
  • This element is consequently manufactured from an insulating substance, and it must be adequately stable, mechanically, thermally and chemically, when disposed within the electrolyte medium. Also, it must not pollute this medium and must not significantly increase the equivalent series (electrical) resistance (ESR) of the capacitor.
  • ESR equivalent series resistance
  • Conventionally, special kinds of papers or coatings are used in a form of thin and very thin layers, in order to provide reliable electrical properties within a wide range of temperatures.
  • Typical thickness of paper separators lies within the range of 25-200 microns, depending on nominal working voltages, while a cloth separator is characterized by a thickness of 110-120 microns and minimum thickness of 40 ⁇ m.
  • Typical thicknesses of paper separators are about 50-60 microns for low-voltage capacitors and 160-200 microns for high voltage capacitors.
  • the dimensionless coefficient of paper separators' permeability ⁇ is about 25-30, and near 10 for cloth-type separators.
  • Extremely thin types of paper separators are about 12-13 microns in thickness. The contribution of conventional separator thickness may be large, e.g. up to 40% of a capacitor's volume.
  • chromium oxide, boric acid and titanium oxide was proposed, to obtain a continuous film of desirable thickness on the electrode surface.
  • another way of manufacturing a separator layer was proposed on the basis of insulating powder (alumina or silica), attachment to the electrode surface being by application of a fusible body, e.g. of ammonium perborate.
  • a fusible body e.g. of ammonium perborate.
  • vacuum deposition of silicon dioxide (or silicates) has been proposed for obtaining a separator coating of desirable properties.
  • An alternative method of pyrolysis of metal salts with a porous refractory oxide to form a separator layer was disclosed in GB Patent No. 1092741.
  • the central idea of this method was thermal decomposition of aluminum nitrate with subsequent deposition of alumina on colloidal silica dust, sintered in turn in order to create a strong bond to the electrode surface during annealing of an electrode foil.
  • the thickness of the separator film is recommended to be more than 10 ⁇ m in order to avoid short circuits between electrodes. It was noted, however, that this coating gave rise to considerable losses of specific capacitance up to 40-50% of the initial value. It may be assumed also, that high losses of specific capacitance are accompanied by corresponding growth of ESR values.
  • the prior methods such as those enumerated above, suffer from similar disadvantages of capacitance decrease, poor adhesion and low porosity and permeability of these coatings.
  • an electrolytic capacitor which includes an anode with an insulating film on its surface, a cathode, an electrolyte in contact with anode and cathode surfaces, and as an integral anode- cathode separator, at least one valve metal oxide layer integral with at least one surface of at least one electrode selected from the anode and the cathode, the average thickness of the integral valve metal oxide separator layer on either or each of the anode or cathode being less than 10 microns.
  • the capacitor may be characterized by absence of any non-integral anode-cathode separator.
  • the anode and the cathode may each (independently) consist essentially of valve metal and the insulating film may consist essentially of valve metal oxide.
  • the presently preferred valve metal and valve metal oxide are aluminum and alumina, respectively.
  • the integral valve metal oxide separator layer is present on the cathode only.
  • the cathode comprises at least one layer of a mixture of valve metal and valve metal oxide deposited thereon prior to deposition of the integral valve metal oxide separator layer.
  • the invention provides a process for the manufacture of the electrolytic capacitor of the invention, which includes the step of subjecting at least one electrode, selected from the anode and the cathode, to vapor deposition of valve metal in presence of oxygen, under conditions such that valve metal oxide is deposited on at least one surface of the at least one electrode, until a predetermined thickness of less than 10 microns valve oxide layer, is obtained.
  • the cathode is subjected to vapor deposition of at least one layer of a mixture of valve metal and valve metal oxide thereon, prior to vapor deposition of valve metal oxide having the above- defined predetermined thickness.
  • the invention provides a cathode for use in the electrolytic capacitor of the invention, which comprises a substantially planar substrate (e.g. a valve metal foil such as Al foil), a first layer consisting essentially of a mixture of valve metal and valve metal oxide deposited on at least one side of the planar substrate, and a further layer consisting of valve metal oxide less than 10 microns thick, deposited on the first layer.
  • a substantially planar substrate e.g. a valve metal foil such as Al foil
  • a first layer consisting essentially of a mixture of valve metal and valve metal oxide deposited on at least one side of the planar substrate
  • a further layer consisting of valve metal oxide less than 10 microns thick
  • the inventive cathode may be made by subjecting the substrate to vapor deposition of least one layer of a mixture of valve metal and valve metal oxide thereon, and then to vapor deposition of valve metal oxide having the above-defined predetermined thickness. Preferably the two vapor deposition steps are carried out consecutively in the same apparatus, without intermediate venting.
  • the electrolytes used in the inventive capacitors may be solid or liquid, and may be organic or inorganic. Reference may be made to our prior US Patent No. 6,287,673 entitled "Method for producing high surface area foil electrodes", for exemplary details relating to the deposition of a mixture of valve metal and valve metal oxide on a substrate. The entire contents of US Patent No. 6,287,673 are incorporated herein by reference.
  • Figure 1 is a sectional view of an electrode with integral separator in accordance with an embodiment of the present invention.
  • the present invention provides in one aspect, an improved design for valve metal electrolytic capacitors.
  • Such capacitors include an anode plate with an insulating film on its surface, a cathode plate, and an electrolyte in contact with the anode and cathode surfaces.
  • the capacitor of the present invention is characterized additionally, by the presence of a porous valve metal oxide coating on at least one external surface of an electrode, preferably on the cathode plate.
  • an improvement in a method for manufacturing capacitors including an electrolyte in contact with an anode foil having an insulating valve metal oxide coating, preferably an aluminum oxide layer on at least one surface thereof and a cathode foil, which comprises the step of vacuum deposition of a porous valve metal (e.g. aluminum) oxide coating on at least one surface of the cathode.
  • a porous valve metal e.g. aluminum
  • the method may be carried out by a deposition rate in the range of about 120-620 A per second, preferably 400-500 A/sec and a pure oxygen atmosphere with the pressure in the range of about 1-2 mTorr, preferably 1.0-1.4 mTorr, or 0 2 /Ar gas mixture with oxygen partial pressure near 1 mTorr and argon pressure 1.3-2.3 mTorr, preferably 1.7-2 mTorr and with substrate temperature in the range of about 200-350°C, preferably 250-300°C.
  • One advantage of the invention is reduced total thickness (diameter) and weight of the product capacitors, which include an anode foil with a dielectric layer, a separator body and a cathode foil, in comparison with conventional capacitors.
  • Another advantage of the invention is a reduced value of ESR, achieved due to a thinner separator body.
  • Still another advantage of the invention is improved purity of electrolyte composition, in particular a diminished quantity of chlorine ions in comparison with standard capacitors.
  • Yet another advantage of the invention is excellent mechanical strength, flexibility and hardness of the produced separator layer.
  • Another advantage is improved thermo-conductivity of a wound capacitor's _ _
  • valve metal is a metal which, when oxidized, allows current to pass if used as a cathode but opposes the flow of current when used as an anode.
  • valve metals include magnesium, thorium, cadmium, tungsten, tin, iron, silver, silicon, tantalum, titanium, aluminum, zirconium and niobium.
  • the integral separator may be applied for coating capacitor cathode (and anode) foils of different origin and for coating both foils simultaneously.
  • This unavoidable treatment of anode foils could in principle change the structure of an alumina separator (if deposited on the anode) and therefore cause undesirable changes in its properties.
  • alumina separator deposition subsequent to such treatment it would unfortunately complicate the technology of manufacturing anode foils.
  • Both above versions of the alumina coating were obtained by vacuum evaporation of pure aluminum in a reactive atmosphere of pure oxygen, or a gas mixture containing oxygen, with the purpose of totally oxidizing deposited aluminum in the course of the deposition process.
  • the foil substrate band of 32/64 microns thickness was either fixed, or moving with uniform velocity, in a source of vaporized aluminum.
  • the rate of aluminum condensation (evaporation), total gas pressure in the vacuum chamber and the foil velocity (when a moving foil was used), were applied to provide a thickness of alumina coating in the range of 0.3-7 ⁇ m, as well as deposited alumina as a porous layer structure.
  • An embodiment of the invention is illustrated in Fig. 1.
  • the electrode with integral separator comprises an aluminum foil 1 , on both sides of which are consequently applied a layer 2 consisting of aluminum and alumina, and a layer 3 consisting of alumina.
  • the thickness of each of layers 2 and 3 is preferably less than 10 microns. It has been found in accordance with an embodiment of the present invention, that the primary (preliminary) vapor deposited sub-layer structure exerts a strong influence on the properties of the subsequently deposited alumina separator layer. In particular, the porosity of this outer alumina separator layer has been found to depend on irregularities of the inner sub-layer.
  • the volume specific capacitance for samples is near 178 ⁇ F/ ⁇ m/cm 2 , compared with 225 ⁇ F/ ⁇ m/cm 2 in absence of the alumina layer (control sample); moreover this proportion is approximately maintained after electrochemical treatment (so-called passivating) of both samples (see Exs.1- 4).
  • De-ionized water 51%, Ethylene-glycol 34%, Ammonium adipate 13%, Ammonium phosphate 1 %, D-gluconic acid 1 %.
  • the electrolyte composition E-ll used for post-deposition samples' treatment has the following components: De-ionized water 1000 ml, Boric acid 30 g/l, Ammonium adipate 30 g/l, Ammonium 2-hydrophosphate 1.5 g/l, Ammonium 5-borate 0.5 g/l.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)
PCT/IL2005/000412 2004-04-25 2005-04-20 Integral separator for electrolytic capacitors WO2005101972A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2007509057A JP4739326B2 (ja) 2004-04-25 2005-04-20 電解コンデンサ用の一体型セパレータ

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IL16160604A IL161606A0 (en) 2004-04-25 2004-04-25 Integral separator for electrolytic capacitors
IL161606 2004-04-25

Publications (2)

Publication Number Publication Date
WO2005101972A2 true WO2005101972A2 (en) 2005-11-03
WO2005101972A3 WO2005101972A3 (en) 2006-02-02

Family

ID=34074032

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IL2005/000412 WO2005101972A2 (en) 2004-04-25 2005-04-20 Integral separator for electrolytic capacitors

Country Status (3)

Country Link
JP (1) JP4739326B2 (ja)
IL (1) IL161606A0 (ja)
WO (1) WO2005101972A2 (ja)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007208254A (ja) * 2006-01-12 2007-08-16 Acktar Ltd 電極、膜、印刷版原版及び多層多孔質皮膜を含む他の物品、及びそれらの製造方法
EP1857573A1 (en) * 2005-01-07 2007-11-21 Daiso Co., Ltd. Insoluble electrode
JP2008270525A (ja) * 2007-04-20 2008-11-06 Fujitsu Ltd 電解コンデンサ
JP2008270524A (ja) * 2007-04-20 2008-11-06 Fujitsu Ltd 電極箔及びその製造方法
WO2008132829A1 (ja) * 2007-04-20 2008-11-06 Fujitsu Limited 電極箔及びその製造方法,並びに電解コンデンサ

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5181401B1 (ja) * 2012-07-12 2013-04-10 日本蓄電器工業株式会社 アルミニウム電解コンデンサ用陰極箔

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6287673B1 (en) * 1998-03-03 2001-09-11 Acktar Ltd. Method for producing high surface area foil electrodes
DE10104573C1 (de) * 2001-02-01 2002-07-18 Epcos Ag Betriebselektrolyt für einen Aluminium-Elektrolyt-Kondensator, Kondensator mit dem Betriebselektrolyten und Verwendung des Kondensators

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1092741A (ja) *
JPH01298713A (ja) * 1988-05-27 1989-12-01 Elna Co Ltd 電解コンデンサ用陰極箔の製造方法
FR2688092B1 (fr) * 1992-02-14 1994-04-15 Traitement Metaux Alliages Sa Feuille pour electrode de condensateur electrolytique et procede de fabrication.
JP2000277386A (ja) * 1999-03-23 2000-10-06 Toyota Motor Corp 電気二重層キャパシタセパレータおよびその製造方法
JP2003297692A (ja) * 2002-03-29 2003-10-17 Nippon Chemicon Corp 固体電解コンデンサ

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6287673B1 (en) * 1998-03-03 2001-09-11 Acktar Ltd. Method for producing high surface area foil electrodes
DE10104573C1 (de) * 2001-02-01 2002-07-18 Epcos Ag Betriebselektrolyt für einen Aluminium-Elektrolyt-Kondensator, Kondensator mit dem Betriebselektrolyten und Verwendung des Kondensators

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1857573A1 (en) * 2005-01-07 2007-11-21 Daiso Co., Ltd. Insoluble electrode
EP1857573A4 (en) * 2005-01-07 2010-07-07 Daiso Co Ltd NON-SOLUBLE ELECTRODE
JP2007208254A (ja) * 2006-01-12 2007-08-16 Acktar Ltd 電極、膜、印刷版原版及び多層多孔質皮膜を含む他の物品、及びそれらの製造方法
JP2008270525A (ja) * 2007-04-20 2008-11-06 Fujitsu Ltd 電解コンデンサ
JP2008270524A (ja) * 2007-04-20 2008-11-06 Fujitsu Ltd 電極箔及びその製造方法
WO2008132829A1 (ja) * 2007-04-20 2008-11-06 Fujitsu Limited 電極箔及びその製造方法,並びに電解コンデンサ
US8213159B2 (en) 2007-04-20 2012-07-03 Fujitsu Limited Electrode foil, method of manufacturing electrode foil, and electrolytic capacitor

Also Published As

Publication number Publication date
IL161606A0 (en) 2004-09-27
JP2007535145A (ja) 2007-11-29
WO2005101972A3 (en) 2006-02-02
JP4739326B2 (ja) 2011-08-03

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