U.S. patent application number 12/759769 was filed with the patent office on 2010-10-21 for hermetically sealed wet electrolytic capacitor.
This patent application is currently assigned to VISHAY SPRAGUE, INC.. Invention is credited to Stephen Breithaupt, Alex Eidelman, Hila Eshel, John Evans, Edward Fairfield, Sarah Lastella, Vicki Segel, Ilia Skatkov, Pavel Vaisman.
Application Number | 20100268292 12/759769 |
Document ID | / |
Family ID | 42224182 |
Filed Date | 2010-10-21 |
United States Patent
Application |
20100268292 |
Kind Code |
A1 |
Eidelman; Alex ; et
al. |
October 21, 2010 |
HERMETICALLY SEALED WET ELECTROLYTIC CAPACITOR
Abstract
A hermetically sealed wet electrolytic capacitor includes a
hermetically sealed case, a cathode, an anode, and an insulator
between the anode and the cathode to provide electrical insulation
between the anode and the cathode. An electrolytic solution is
disposed within the case. A first terminal is electrically
connected to the anode and a second terminal is electrically
connected to the cathode. The cathode comprises a metal substrate
having an alloy layer formed with a noble metal and a noble
metal/base metal electrode element layer electrochemically
deposited thereon. The electrolytic solution has a conductivity
between 10 and 60 mS/cm. The capacitor may be used in an
implantable device.
Inventors: |
Eidelman; Alex; (Beer-Sheva,
IL) ; Skatkov; Ilia; (Beer-Sheva, IL) ; Segel;
Vicki; (Beer-Sheva, IL) ; Vaisman; Pavel;
(Beer-Sheva, IL) ; Eshel; Hila; (Beer-Sheva,
IL) ; Evans; John; (Pownal, VT) ; Breithaupt;
Stephen; (N. Bennington, VT) ; Lastella; Sarah;
(Troy, NY) ; Fairfield; Edward; (Hopkinton,
NH) |
Correspondence
Address: |
VOLPE AND KOENIG, P.C.
UNITED PLAZA, 30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
VISHAY SPRAGUE, INC.
Bennington
VT
|
Family ID: |
42224182 |
Appl. No.: |
12/759769 |
Filed: |
April 14, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61169764 |
Apr 16, 2009 |
|
|
|
Current U.S.
Class: |
607/5 ; 29/25.03;
361/518 |
Current CPC
Class: |
A61N 1/3975 20130101;
H01G 9/145 20130101; H01G 9/012 20130101; H01G 9/0029 20130101;
H01G 9/008 20130101; H01G 9/10 20130101; H01G 9/035 20130101 |
Class at
Publication: |
607/5 ; 361/518;
29/25.03 |
International
Class: |
A61N 1/39 20060101
A61N001/39; H01G 9/10 20060101 H01G009/10 |
Claims
1. A hermetically sealed wet electrolytic capacitor, comprising: a
hermetically sealed case; a cathode having a first terminal; an
anode having a second terminal; an insulator between the anode and
the cathode for providing electrical insulation between the anode
and the cathode; and an electrolytic solution disposed within the
case; wherein the hermetically sealed wet electrolytic capacitor is
adapted to delivery at least 80 percent of stored energy between
the first and second terminals.
2. The hermetically sealed wet electrolytic capacitor of claim 1
wherein the cathode comprises a metal substrate having an alloy
layer formed with a noble metal and a noble metal/base metal
electrode element layer electrochemically deposited thereon.
3. The hermetically sealed wet electrolytic capacitor of claim 2
wherein the metal substrate comprises a valve metal.
4. The hermetically sealed wet electrolytic capacitor of claim 3
wherein the metal substrate comprises tantalum, niobium, hafnium,
zirconium, titanium or alloys thereof.
5. The hermetically sealed wet electrolytic capacitor of claim 1
wherein the electrolytic solution has conductivity between 10 and
60 mS/cm.
6. The hermetically sealed wet electrolytic capacitor of claim 5
wherein the electrolytic solution comprises water, inorganic acids
(phosphoric and boric), an organic acid (oxalic) and an organic
solvent.
7. An implantable device including the hermetically sealed wet
electrolytic capacitor of claim 1.
8. An implantable cardioverter defibrillator (ICD) including the
hermetically sealed wet electrolytic capacitor of claim 1.
9. An implantable device including: a battery; a processor coupled
to the battery; and a capacitor coupled to the battery and the
processor, including; a hermetically sealed case; a cathode
including a first terminal; an anode including a second terminal;
an insulator between the anode and the cathode which provides
electrical insulation between the anode and the cathode; and an
electrolytic solution disposed within the case having conductivity
between 10 and 60 mS/cm; wherein the cathode comprises a metal
substrate having an alloy layer formed with a noble metal and a
noble metal/base metal electrode element layer electrochemically
deposited thereon; and whereby the capacitor is adapted to provide
at least 80% of its stored energy between said first and second
terminals in a single discharge.
10. The hermetically sealed wet electrolytic capacitor of claim 9
wherein the metal substrate comprises a valve metal.
11. The hermetically sealed wet electrolytic capacitor of claim 10
wherein the metal substrate comprise tantalum, niobium, hafnium,
zirconium, titanium or alloys thereof.
12. The hermetically sealed wet electrolytic capacitor of claim 9
wherein the electrolytic solution comprises water, inorganic acids
(phosphoric and boric), an organic acid (oxalic) and an organic
solvent.
13. The hermetically sealed wet electrolytic capacitor of claim 9
being adapted to provide pulse delivery of at least 80 percent,
preferably greater than 87 percent, of stored energy to the first
and second terminals.
14. An implantable device comprising the hermetically sealed wet
electrolytic capacitor of claim 9.
15. An implantable cardioverter defibrillators (ICD) comprising the
hermetically sealed wet electrolytic capacitor of claim 9.
16. A method of manufacturing a capacitor, comprising: hermetically
sealing a case wherein an electrolytic solution being disposed
within the case, the electrolytic solution having a conductivity
between 10 and 60 mS/cm; electrically connecting a first terminal
to an anode, the anode being insulated from a cathode; and
electrically connecting a second terminal to the cathode, the
cathode comprising a metal substrate having an alloy layer formed
with a noble metal and a noble metal/base metal electrode element
layer electrochemically deposited thereon.
17. The method of claim 16 further comprising preparing the
electrolytic solution by admixing water, inorganic and organic
acids, and an organic solvent.
Description
[0001] This application claims priority to U.S. Provisional Patent
Application No. 61/169,764, filed on Apr. 16, 2009.
FIELD OF THE INVENTION
[0002] The present invention relates to capacitors, and more
specifically to a capacitor suitable for use in medical
applications such as implantable cardioverter defibrillators.
BACKGROUND
[0003] Capacitors are used in a wide range of electronic
applications. Certain applications require a capacitor which is
capable of a rapid electrical charge to a pre-determined voltage
and, once charged, is also capable of delivering sizeable pulses of
energy. One example of such an application is in implantable
devices. In such an application, it is also important that the
capacitor be compact in size and highly reliable.
[0004] Thus, what is needed is a capacitor suitable for use in
applications, such as implantable cardioverter defibrillators,
where reliability and performance are provided in a small size.
SUMMARY
[0005] Therefore, it is a primary object, feature, or advantage of
the present invention to improve over the state of the art.
[0006] It is a further object, feature, or advantage of the present
invention to provide a capacitor suitable for use in implantable
devices.
[0007] A still further object, feature, or advantage of the present
invention is to provide a capacitor that is capable of a rapid
electrical charge to a pre-determined voltage and, once charged, is
also capable of delivering sufficient pulses of energy to restore
the normal function of a patient's heart when used in implantable
cardioverter defibrillators (ICD).
[0008] Another object, feature, or advantage of the present
invention is to provide a capacitor which is efficiently
constructed and shaped to fit into the limited volume available
within an ICD.
[0009] Yet another object, feature, or advantage of the present
invention is to provide a capacitor with high performance and high
reliability.
[0010] One or more of these and/or other objects, features, or
advantages of the present invention will become apparent from the
specification and claims that follow.
[0011] According to one aspect of the present invention, a
hermetically sealed wet electrolytic capacitor is provided. The
capacitor has a hermetically sealed case that encloses a cathode,
an anode, an electrical insulator between the anode and the cathode
and an electrolytic solution. A first terminal is electrically
connected to the anode and a second terminal electrically connected
to the cathode. The hermetically sealed wet electrolytic capacitor
is able to provide a pulse delivery equal to at least 80 percent of
the stored energy.
[0012] According to another aspect of the present invention, the
capacitor's cathode includes a metal substrate having an alloy
layer formed with a noble metal and a noble metal/base metal
electrode element layer electrochemically deposited thereon, and
the electrolytic solution has a conductivity between 10 and 60
mS/cm.
[0013] According to another aspect of the present invention, a
method of manufacturing a capacitor is provided. The method
includes hermetically sealing a case containing an electrolytic
solution having a conductivity between 10 and 60 mS/cm. The method
further includes electrically connecting a first terminal to an
anode, the anode being insulated from a cathode. The method further
includes electrically connecting a second terminal to the cathode.
The cathode is formed from a metal substrate having an alloy layer
formed with a noble metal and a noble metal/base metal electrode
element layer electrochemically deposited thereon.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 illustrates one embodiment of a hermetically sealed
wet electrolytic capacitor.
[0015] FIG. 2 illustrates the capacitor of FIG. 1 placed in an
implantable cardioverter defibrillator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] The present invention is now described with respect to a
particular embodiment. That which is shown is merely for purposes
of illustration and example, and one skilled in the art will
understand that the present invention contemplates other options,
alternatives, or variations.
[0017] FIG. 1 illustrates one embodiment of a capacitor 10 of the
present invention. Although shown in a semi-circle shape, the
capacitor 10 need not have such a shape. This particular shape is
merely an example. In FIG. 1, a hermetically sealed wet
electrolytic capacitor 10 is shown. The capacitor 10 has a
hermetically sealed case 12. The capacitor 10 has a cathode 18 and
an anode 16. One example design for an anode 16 would comprise
sodium reduced capacitor grade tantalum powder pressed to a green
density of between 5.0 and 7.0 grams/cc then vacuum sintered
between 1450.degree. C. and 1650.degree. C. Powder, press and
sinter conditions may be varied to attain the requisite
capacitance. Formation of the anode should be in an electrolyte
capable of sustaining the voltage necessary for the required oxide
thickness.
[0018] An insulator 14, (preferably, but not required, comprising
one or more layers of a polymeric material), is positioned between
the anode 16 and the cathode 18 to electrically insulate the anode
16 from the cathode 18. An electrolytic solution 22 is disposed
within the hermetically sealed case 12 and surrounds both the
cathode 18 and the anode 16. The electrolytic solution 22
preferably comprises a gel which includes DI water, organic and
inorganic acids and an organic solvent. The constituent components
of the electrolytic solution 22 may be admixed in a variety of
concentrations to provide conductivity within a preferred range
between 10 and 60 mS/cm. One example of such an electrolytic
solution 22 would be:
[0019] 65-80% DI water
[0020] 0.2-0.6% phosphoric acid
[0021] 15-30% ethylene glycol
[0022] 3-6% oxalic acid
[0023] 2-4% boric acid
[0024] The cathode 18 is formed from a metal substrate 20 having an
alloy layer 24 formed with a noble metal and a noble metal/base
metal electrode element layer 26 electrochemically deposited on the
alloyed surface from a solution of the metal salts. One example
design for the cathode 18 may be a mixture of Pd and Cu
electrodeposited on a Ti--Pd alloy. To increase adhesion of the
cathode 18 to the alloyed substrate, an initial smooth film of
Pd--Cu may be electrodeposited as a tacking layer. A rough, high
surface area layer can then be deposited on top of the tacking
layer to achieve a high capacitance cathode 18.
[0025] The metal substrate 20 of the cathode 18 can be formed of a
valve metal. Examples of such valve metals include tantalum,
niobium, hafnium, vanadium, zirconium, titanium or any of their
alloys. The metal substrate 20 may have any number of shapes or
configurations, including a planar or cylindrical shape. The metal
substrate 20 may be a liner of any suitable shape and may represent
a part of the capacitor case 12. Such a construction of the cathode
18 results in high cathode capacitance which assists in efficiently
delivering energy stored in the capacitor 10 to a load.
[0026] A first terminal 30 is shown extending through a spacer 32.
The first terminal 30 is electrically connected to the anode 16. A
second terminal 36 is electrically connected to the cathode 18.
[0027] FIG. 2 illustrates one embodiment of an implantable
cardioverter defibrillator (ICD) device 40. The device 40 includes
the capacitor 10 of FIG. 1 (with a first terminal 30 and a second
terminal 36), and a control circuit 42, which is electrically
coupled to the capacitor 10, a detector 43 and a battery 44. The
capacitor 10 is configured to provide a pulse delivery of at least
80 percent, (but preferably greater than 87 percent), of stored
energy between the first and second terminals 30, 36. The detector
43 monitors a patient's condition and provides this patient data to
the control circuit 42. The control circuit 42 monitors the
information from the detector and upon detection of an anomaly or a
critical condition, (which may be defined as one or more
predetermined parameters that have exceeded one or more
predetermined thresholds).
[0028] By way of example, the detector 43 may detect electrical
activity in the heart of a patient and forward this data to the
control circuit 42. The control circuit 42 monitors this electrical
activity and if it drops below a certain electrical level, or if
the electrical activity becomes irregular (as happens with an
arrhythmia), initiates delivery of an electrical shock.
[0029] The battery 44 may be used to charge the capacitor 10 and to
power the ICD device. The charging of the capacitor 10 may be
constant (to counter the effects of charge leakage), such that the
capacitor 10 is always ready for discharge; may be periodic (i.e.
charging at predetermined intervals to keep the charge level of the
capacitor 10 above a predetermined threshold); or may be on demand,
such that when the onset of an anomaly is detected, the battery 44
is used to charge the capacitor at that time.
[0030] In the application of an ICD device 40, the capacitor 10
performs the function of delivering electrical shock therapy into
the heart of a patient when a control circuit 42 of the ICD device
40 detects an anomaly or a critical condition in the patient. The
capacitor 10 allows the capacitor to be capable of providing a
rapid electrical charge to a pre-determined voltage, and thereafter
delivering one or more pulses of sufficient energy to restore
normal functions of a patient's heart.
[0031] The capacitor 10 as shown in FIG. 1 is efficient in nature
and highly compact such that the capacitor 10 is constructed and
shaped to fit within a limited volume within an ICD device 40.
Preferably, the size of the capacitor 10 is 1.5-3.0 CC, and
comprises a half-moon shape as shown in FIG. 1, although this
should not be construed to be limiting to the present invention.
The capacitor 10 is able to conform to any size and shape in order
to fit the particular configuration demanded by the person within
which it is being implanted.
[0032] In order to support the application of an ICD device 40, the
capacitor 10 is able to supply a minimum of 9J, (but preferably
12J), upon demand. The amount of energy actually delivered is
determined by the control circuit 42
[0033] A hermetically sealed wet electrolytic capacitor has been
described. The present invention is not to be limited to the
specific embodiment shown or described herein as the present
invention contemplates variations in the size and shape of the
capacitor, variations in the materials used, and other variations,
alternatives, and options as would be apparent to one skilled in
the art.
* * * * *