(19) United States
`(12) Patent Application Publication (10) Pub. N0.: US 2001/0024353 A1
`(43) Pub. Date:
`Sep. 27, 2001
`Sanger et al.
`
`US 200l0024353A1
`
`(54) LOW-INDUCTANCE CAPACITOR AND A
`METHOD FOR MINIMIZING INDUCTANCE
`IN A SNUBBER CIRCUIT
`
`(76)
`
`Inventors: Phillip A. Sanger, Avon Lake, OH
`(US); Lyon Mandelcorn, Pittsburgh, PA
`(US); Leban E. Lesster, Boston, MA
`(US); Frank A. Lindberg, Baltimore,
`MD (US)
`
`Correspondence Address:
`Dike, Bronstein, Roberts & Cushman
`Intellectual Property Practice Group
`EDWARDS & ANGELL, LLP
`130 Water Street
`
`Boston, MA 02109 (US)
`
`(21) Appl. No.:
`
`09/809,907
`
`(22)
`
`Filed:
`
`Mar. 16, 2001
`
`Related U.S. Application Data
`
`(63) Non-provisional of provisional
`60/189,963, filed on Mar. 17, 2000.
`
`application No.
`
`Publication Classification
`
`Int. Cl.7 ..................................................... ..H0lG 9/02
`(51)
`(52) U.S.Cl.
`............................................................ ..361/512
`
`(57)
`
`ABSTRACT
`
`A low-voltage, low-inductance device [or storing electrical
`charge in a snubber circuit is disclosed as well as a method
`of minimizing inductance in the snubber circuit using the
`device. The device, a capacitor, comprises a plurality of
`extended electrodes, in parallel or series, that are joined to
`a positive conductor terminal at one end spray and at a
`negative conductor terminal at the other end spray so that
`end sprays of adjacent extended electrodes are alternately
`joined to the positive and negative conductor terminals.
`Accordingly, current flowing though adjacent extended elec-
`trodes is of substantially equal intensity but different in
`direction. As a result, inductance produced effectively can-
`cels out that of adjacent extended electrodes. The method
`includes sandwiching an insulating film between the posi-
`tive and negative conductor terminals and alternately joining
`the conductor terminals to the end sprays of extended
`electrodes so that current
`flows in opposite directions
`between end sprays of adjacent extended electrodes, thereby
`canceling out inductance.
`
`000001
`
`Exhibit 1021
`
`IPR20l6-00636
`
`Exhibit 1021
`IPR2016-00636
`AVX Corporation
`AVX Corporatio
`
`000001
`
`

`

`Patent Application Publication
`
`Sep. 27, 2001 Sheet 1 of 4
`
`US 2001/0024353 A1
`
`1
`
`//0
`
`000002
`
`000002
`
`

`

`aD1
`
`nrA
`
`mjM»Va
`
`t
`
`Sep 27,2001
`
`fl.0
`
`1AA
`
`n_
`
`3-1mw2mm.1a.Jr«(a
`
`mm74Aims/s\,mLi...\/_z
`
`mm.:z§;fs.;V.4‘;4//.4/\SAlina6PFU731/iwM
`
`I/.4/J;.
`
`
`
`s;@m..e§:s;s§a:4mw:§-;;£
`Tx“;g.11?/.H___3,.._aT4__.m;:;::;;::_.n1.asatin
`
`nrLu__s¢_m.m_N__flfill.H.3m:
`
`M...X
`.m.._pr.‘-:naww:nuwunnuw,.T:;:ss;x:uz:¢
`
`
`
`2.giI21:nI4ilYIDt1...;1!i1{.2%3;.«....m.,.w_Tifi.
`-.4.fi__,mAS53;./I_V/23.L71»
`
`§_/5;
`
`‘ 4:
`
`L/
`
`3
`
`L____”_
`
`‘
`
`
`
`22.
`
`/~7
`
`000003
`
`000003
`
`

`

`Patent Application Publication
`
`Sep. 27, 2001 Sheet 3 of 4
`
`US 2001/0024353 A1
`
`000004
`
`000004
`
`

`

` PatentApplicationPublication
`
`Sep. 27, 2001 Sheet 4 of 4
`
`US 2001/0024353 A1
`
`/=7
`
`000005
`
`000005
`
`

`

`US 2001/0024353 Al
`
`Sep. 27, 200]
`
`LOW-INDUCTANCE CAPACITOR AND A
`METHOD FOR MINIMIZING INDUCTANCE IN A
`SNUBBER CIRCUIT
`
`REFERENCE TO RELATED APPLICATIONS
`
`[0001] The present invention claims a right of priority to
`provisional application Ser. No. 60/189,963 entitled Low
`Inductance Capacitor filed on Mar. 17, 2000.
`
`FIELD OF THE INVENTION
`
`[0002] The present invention relates to devices for electric
`circuitry. More precisely, the invention relates to low voltage
`capacitors that produce minimal inductance, e.g., for snub-
`ber circuitry, and to methods for minimizing inductance in
`same.
`
`BACKGROUND OF THE INVENTION
`
`[0003] Capacitance, i.e., the ability of capacitors to store
`charge, plays a dominant role in shaping the time and
`frequency response of modern electrical circuitry. However,
`capacitance can be affected deleteriously by stray induc-
`tance, which is a flux field that is produced by current
`flowing through wires and/or conduction paths of substan-
`tially all electrical circuits and circuitry. Indeed, current (I)
`flowing through circuitry can cause significant voltages (V)
`to develop across stray inductance (L), which condition
`diminishes capacitance
`Therefore, for optimal perfor-
`mance, inductance associated with capacitors must be as low
`as possible. This is especially true at higher frequencies, i.e.,
`5 kHz and higher, where inductive impedance diminishes
`capacitive effectiveness by amplifying microsecond pulses
`to high voltage levels.
`
`[0004] This is particularly true of snubber capacitors,
`which are connected in parallel with one or more switches
`as part of a snubber circuit. Snubber circuits typically are
`used to
`reduce voltage spikes, e.g., switching pulses, that
`occur when power switches are turned on and off,
`i.e.,
`“switched”, repeatedly and (ii) to reduce power and other
`losses that also result from repeated switching. Indeed,
`power loss, which is defined by the equation P=V><I, is
`substantially zero when either there is no current flow, i.e.,
`I=0, which occurs when the switch is off, and/or when the
`voltage is very low,
`i.e., V=>0. When neither of these
`conditions exists, the circuitry experiences significant power
`loss.
`
`[0005] As a result, snubber capacitors, which typically
`operate at high current levels, i.e., I>>0, by default, must be
`designed to suppress switching pulses in inverter circuits to
`as low voltage levels as possible. Accordingly, the use of
`snubber capacitors in this capacity requires a very low
`inductance, otherwise, solid state devices, e.g.,
`insulated
`gate bi-polar transistors (“IGBTS”), and/or insulation may
`fail if the inductance and associated voltage are too high.
`
`DESCRIPTION OF THE RELATED ART
`
`[0006] Bowers (U.S. Pat. No. 6,166,932) discloses snub-
`ber circuitry that minimizes oscillations that are caused by
`repeated switching. Indeed, the snubber circuitry of Bowers
`includes a pair switches in parallel with a pair of capacitors,
`wherein an air-core transformer that is in series with a
`relatively high value resistor is disposed in close proximity
`of the capacitors to inductively couple resistance in the
`
`branch circuit without introducing additional stray induc-
`tance, which might otherwise be the case were the resistors
`directly connected to the capacitors in series. Hence, Bowers
`purports to reduce inductance in the snubber circuitry by
`providing distance between the resistors and the capacitors.
`
`the prior art keeps inductance in
`[0007] Furthermore,
`interconnects and terminals by making interconnects and
`terminals as short as possible and/or by reducing the dis-
`tance between adjacent edges of terminals.
`
`the prior art has apparently failed to
`[0008] However,
`appreciate that to obtain low inductance in snubber capacitor
`design:
`the cross-sectional area of the capacitor should be
`as large as possible, while the length, however, is kept to a
`minimum; (ii) design includes a high aspect ratio for low
`cross-sectional charge density; and (iii) conductors and/or
`terminals of opposite polarity should be disposed as close to
`one another as possible so that their respective flux fields—
`which produce inductance—substantially cancel out each
`other.
`
`SUMMARY OF THE INVENTION
`
`[0009] The present invention produces a low-inductance
`capacitance device, which is particularly useful with snub-
`ber circuitry. The cross-sectional area of the disclosed
`capacitor is relatively large although its length is kept to a
`minimum. The present invention provides a capacitor that
`includes a high aspect ratio for low cross-sectional charge
`density. Furthermore,
`the present
`invention comprises
`capacitors in combination with conductors and/or terminals
`of opposite polarity that are disposed close to one another so
`that the inductance produced by the flux fields substantially
`cancels out each other.
`
`[0010] Accordingly, the invention provides a low-induc-
`tance device for storing electrical charge comprising a
`plurality of extended electrodes, wherein electrical current
`passing through a extended electrode from said plurality of
`extended electrodes flows in a direction opposite of current
`passing through one or more adjacent extended electrodes of
`said plurality of extended electrodes to provide cancellation
`of inductance in the device.
`
`[0011] The invention as provides a method of reducing the
`inductance of a device used for storing an electrical charge,
`the device having a plurality of extended electrodes having
`a first end spray and a second end spray,
`the method
`comprising the steps of: sandwiching an insulating film
`between a positive conductor terminal and a negative con-
`ductor terminal; and joining said negative conductor termi-
`nal to each of the plurality of extended electrodes at a first
`end spray and said positive conductor terminal to each of the
`plurality of extended electrodes at a second end spray so that
`the end sprays of adjacent extended electrodes are joined to
`the negative conductor terminal and the positive conductor
`terminal alternately so that current flows in opposite direc-
`tions between first and second end sprays of adjacent
`extended electrodes.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0012] For a fuller understanding of the nature and desired
`objects of the present invention, reference is made to the
`following detailed description taken in conjunction with the
`accompanying drawing figures wherein like reference char-
`acter denote corresponding parts throughout
`the several
`views and wherein:
`
`000006
`
`000006
`
`

`

`US 2001/0024353 A]
`
`Sep. 27, 200]
`
`[0013] FIG. 1 shows an embodiment of a conventional
`capacitor having parallel sections;
`
`[0014] FIG. 2A shows an illustrative embodiment of a
`snubber capacitor having parallel sections according to the
`present invention;
`
`[0015] FIG. 2B shows an illustrative embodiment of a
`capacitor section according to the present invention;
`
`[0016] FIG. 3A shows another illustrative embodiment of
`a snubber capacitor having parallel sections according to the
`present invention;
`
`[0017] FIG. 3B shows a sectional view of the conductor-
`insulating film-conductor sandwich taken along line 3B-3B
`in FIG. 3A;
`
`[0018] FIG. 4 shows an embodiment of a conventional
`capacitor having terminals and interconnects in series;
`
`[0019] FIG. 5 shows an illustrative embodiment of a
`snubber capacitor having sections in series according to the
`present invention;
`
`[0020] FIG. 6A shows a second illustrative embodiment
`of a snubber capacitor having sections in series according to
`the present invention; and
`
`[0021] FIG. 6B shows a third illustrative embodiment of
`a snubber capacitor having sections in series according to
`the present invention.
`
`DETAILED DESCRIPTION OF THE
`INVENTION AND PREFERRED
`EMBODIMENTS
`
`[0022] FIG. 1 shows an example of a conventional capaci-
`tor 10, having parallel sections 11, interconnects 12, and
`terminals 15, 16, commonly found and practiced in the prior
`art. Shown is a capacitor 10 with four sections 11, which are
`labeled A, B, C, and D. Each section 11 comprises a pair of
`end sprays 14, which are disposed at a distal and a proximal
`end of the section 11. Because the sections 10 are connected
`
`in parallel, four end sprays 14 common to the distal end are
`connected to a first terminal 15 and four end sprays 14
`common to the proximal end are connected to a second
`terminal 16.
`
`[0023] The sections 11 of the capacitor 10 are oriented in
`a common direction (as shown by the arrows). Conse-
`quently, as current I passes through the first terminal 15 and
`through the sections 11, the current 1 produces, i.e., induces,
`inductance, which has a common direction. Accordingly, the
`total inductance produced by the capacitor 10 is the sum of
`the individual inductances produced by the sections A, B, C,
`and D.
`
`[0024] By comparison, FIG. 2A shows an illustrative
`embodiment of the present invention for capacitor sections
`11 in parallel. Shown are the intereonnect-terminal arrange-
`ments for a capacitor 10 having four metallized film sections
`11 in parallel. It should be noted that those skilled in the
`pertinent art can design capacitors 10 with more or fewer
`metallized film sections 11 without violating the scope and
`spirit of this disclosure.
`
`[0025] The capacitor 10 includes a conductor-insulator-
`conductor sandwich 20 arrangement, which provides both
`interconnects 12 and terminals 15 and 16 for a bank of
`extended electrodes, e.g., metallized film sections or MLC
`
`the conductor-insulator-conductor
`layers, 11. Preferably,
`sandwich 20 comprises two substantially planar, i.e., sub-
`stantially flat, approximately 5 to 20 mil thick by 3A: inch
`wide conductors 15 and 16 that are separated by an approxi-
`mately 3 mil thick by 7/3 inch wide layer of insulating film
`21. It is important that the insulating film layer 21 extend
`beyond the edges, i.e., the outer perimeter, of the conductors
`15 and 16 in all directions to further minimize inductance.
`Indeed, insulating films 21 isolate end sprays 22 attached to
`one of the conductors from adjacent end sprays 22 as well
`as from the other conductor.
`
`[0026] For example, preferably, the conductors 15 and 16
`are flat metal sheets, e.g., made of copper or aluminum, that
`are joined, e.g., laminated, to produce a conductor-insulating
`film-conductor sandwich 20. Current I of substantially equal
`intensity flows in opposite directions in conductors 15 and
`16 (as shown by arrows in FIG. 2A). As a result,
`the
`magnetic flux fields induced by the conductors 15 and 16
`overlap and effectively cancel, which is to say, that induc-
`tance produced by the first conductor 15 is substantially
`equal in intensity but opposite in direction to the inductance
`produced by the second conductor 16. Consequently, net
`inductance is negligible.
`
`[0027] Preferably, the conductors 15 and 16 are joined to
`either the first end spray 22a or the second end spray 22b of
`the each of the four sections 11 in an alternating fashion. For
`example, the first end spray 22a of section A is joined to the
`first conductor 15 and the second end spray 22b of section
`A is joined to the second conductor 16. Section B, which is
`immediately adjacent to section A, is joined just the oppo-
`site, i.e., the first end spray 22a of section B is joined to the
`second conductor 16 and the second end spray 22b of section
`B is joined to the first conductor 15. Sections C and D are
`joined to the conductors 15 and 16 in like manner as
`described for sections A and B, respectively.
`
`[0028] Preferably, end sprays 22 are joined to the negative,
`inner conductor 16 by spot welding and to the positive, outer
`conductor 15 using an extension spot weld, i.e., connected
`through bridging tabs (not shown) that extend beyond the
`edge of the conductors 15 and 16. The negative,
`inner
`conductor 16 is isolated from the end sprays 22 to which it
`is not joined and the end sprays 22 are isolated from each
`other by an insulating film collar 23. In one embodiment, the
`insulating film collar 23 comprises an approximately 3 mil
`thick, 5/3 inch wide collar that is disposed about each end
`spray 22 about 1/15 inch beyond the windings. It will become
`obvious to those skilled in the art that the present invention
`can be practiced using other methods of joining end sprays
`22 to the conductors 15 and 16, which methods are within
`the scope and spirit of this disclosure.
`
`[0029] Accordingly, the current I flowing in each of the
`sections 11 is substantially equal in intensity but opposite in
`direction to current flowing in adjacent sections 11. Thus,
`magnetic flux fields induced by the current I flowing in the
`sections 11 overlap and effectively cancel, which is to say,
`that inductance produced by the sections A and C is sub-
`stantially equal in intensity but opposite in direction to the
`inductance produced by the sections B and D so that the net
`inductance is negligible.
`
`[0030] For example, a metallized polypropylene film
`capacitor 10 was built using two 14 ‘uF (“micro-Farads”)
`sections and two 12 ,uF sections according to the present
`invention and tested. The conductors 15 and 16 extended
`about 1-1/4 inch beyond the edge of the bank of sections 11.
`The section end sprays 22 were about 3%: inch Wide, about
`
`000007
`
`000007
`
`

`

`US 2001/0024353 Al
`
`Sep. 27, 200]
`
`3 mil thick, and about 1-1/2 inches high. Furthermore, the first
`end spray 22a was about 1-5/3 inches from the second end
`spray 22b. See FIG. 2B. The inductance measured during
`testing was about 3.2 nII (“nano-IIenrys”). By comparison,
`the inductance produced in a comparable, conventional
`MP8-12820K, 52 uF, 600V-type snubber capacitor from
`Electronics Concepts, Inc. (“ECI”) is about 24.8 nH. As a
`result, the present invention produces about one-eighth the
`inductance as a conventional capacitor. Correspondingly, the
`snubber capacitor of the present invention reduces induc-
`tance in the snubber circuitry by almost 90 percent from
`conventional snubber capacitors.
`
`[0031] An alternative embodiment of the present inven-
`tion preferably uses substantially flat, overlapping conduc-
`tors 15 and 16 that are disposed in a conductor-insulating
`film-conductor sandwich 20 similar to the one that has been
`described above. See FIG. 3A. As with the first embodi-
`ment, the two conductors 15 and 16 are substantially planar
`and are joined, e.g., laminated, so that an insulating film 21
`extends beyond the edges, i.e., the outer perimeter of the
`conductors 15 and 16. The insulating film 21 isolates elec-
`trode terminations 32 from the overlaying conductor 16, or,
`alternatively, the underlying conductor 15 as well as from
`adjacent electrode terminations 32.
`
`[0032] Electrode tabs 31a and 31b are joined to the
`underlying first conductor 15 and the overlying second
`conductor 16, respectively, e.g., by soldering. See FIG. 3B.
`Alternately, the conductors 15 and 16 can be manufactured
`with the electrode tabs 31a and 31b, respectively, e.g., by
`stamping from the same sheet metal. In this latter embodi-
`ment, the electrode tabs 31a and 31b are disposed approxi-
`mately perpendicular to the conductors 15 and 16, i.e., the
`z-direction, which is to say that the electrode tabs 31a and
`31b are bent upwards.
`
`[0033] An embodiment using sections 11 in series will
`now be discussed. With the prior art, when two sections 11
`are in series, the simplest interconnection 12 between adja-
`cent electrodes extensions 32 or end sprays 22 produces
`mutual cancellation of inductance through the sections 11a
`and 11b as current I of substantially equal intensity flows in
`opposite directions. See FIG. 4. However, with conven-
`tional snubber capacitors 10 in series, the terminals 15 and
`16 are disposed too far apart relative to the other for
`significant inductance cancellation.
`
`[0034] Referring to FIG. 5, an illustrative embodiment of
`a capacitor 10 comprising sections 11a and 11b in series
`according to the present invention is shown. While only two
`sections 11a and 11b are shown in FIG. 5, those skilled in
`the pertinent art can practice the disclosed invention using
`more sections 11 in series without violating the scope and
`spirit of this disclosure.
`
`[0035] A first terminal 15 is joined to the first electrode
`termination 32a of the first section 11a. Current I passes
`from the first electrode termination 32a to the second
`electrode termination 32b in the direction shown, producing
`inductance. The second electrode termination 32b of the first
`section 11a is interconnected to the first electrode termina-
`tion 32a of the second section 11b by an interconnection 12.
`Current I passes from the first electrode termination 32a to
`the second electrode termination 32b in the direction shown,
`which direction is opposite of that of the first section 11a,
`also producing inductance. The second electrode termina-
`tion 32b of the second section 11b is joined to the second
`terminal 16, which terminal 16 is separated from the first
`
`terminal 15 by an insulation film 21. Preferably, the elec-
`trode terminations 32a and 32b are joined to the intercon-
`nection 12 and terminals 15 and 16, e.g., by soldering.
`
`[0036] For example, two metallized film PET capacitors
`10 with two sections 11 in series were built to provide a
`capacitance of about 39 ,uF and tested. At a frequency of
`about 1 MHZ, the conventional capacitor 10 produced an
`inductance of about 6.9 nH for 19.7 ,uF. By comparison, a
`series capacitor 11 built in accordance with the present
`invention, having an insulating film 21 thickness of about
`2.4 pm, produced an inductance of about 6.0 nH at the same
`frequency and capacitance. As a result, the present invention
`produces about 13 percent less inductance than the conven-
`tional capacitor.
`
`[0037] However, with this embodiment, the effect of sand-
`wiching, or overlapping, the terminals 15 and 16 is limited
`to currents I in two adjacent capacitor sections 11a and 11b,
`which essentially are contiguous at some point with each
`other, and to a small depth into the windings. The magnetic
`flux fields due to the rest of the current elements in a winding
`are not exposed to canceling flux fields.
`
`[0038] FIGS. 6A and 6B show two additional embodi-
`ments for sections 11 in series for reducing inductance
`further. FIG. 6a shows a first and second section 11a and
`11b of a capacitor 10 that
`include an insulated central
`interconnect 25. The insulated central section 25a of the first
`section 11a is interconnected to the insulated central section
`25b of the first section 11b by an interconnection 12. The
`combination of the two insulated central sections 25a and
`25b and the interconnection 12 create a bridging conductor
`27.
`
`[0039] Current I from the first terminal 15 passes from the
`first electrode termination 32a to the second electrode ter-
`mination 32b of the first section 11a, where it passes through
`a first central interconnect 25a to an interconnection 12 and
`then to a second central interconnect 25b. The currentI then
`passes to the first electrode termination 32a and on to the
`second electrode termination 32b of the second section 11b,
`where it passes to the second terminal 16. As the current I
`arrows in the FIG. 6A show, current I flowing through the
`central interconnects 25a and 25b is substantially equal in
`magnitude but opposite in direction of the current I flowing
`between the first and second electrode terminations 32a and
`32b of each of the sections 11a and 11b. The magnetic flux
`field produced by current I flowing in the bridging conductor
`27 is in relatively close proximity to and, accordingly,
`cancels some but not all of the magnetic field produced by
`current flowing between the electrode terminations 32a and
`32b in both section 11a and 11b. Furthermore, the current I
`flowing in the first and second terminals 15 and 16 are in
`relatively close proximity so that the magnetic flux fields
`associated with each are substantially mutually canceling.
`
`[0040] FIG. 6B shows another embodiment of a capacitor
`10 similar to the embodiment described with reference to
`FIG. 6A. Indeed, the embodiment shown in FIG. 6B differs
`from the embodiment shown in FIG. 6A by the relative
`location of the bridging conductor 27 with respect to the
`second terminal 16. Indeed, with FIG. 6A, the interconnec-
`tion 12 of the bridging conductor 27 is disposed above the
`second terminal 16 with insulation 28 therebetween.
`In
`contrast, with FIG. 6B, the second terminal 16 is disposed
`above the interconnection 12 of the bridging conductor 27
`with insulation 28 disposed therebetween as well as between
`the interconnection 12 and the electrode terminations 32a
`and 32b of the sections 11a and 11b, respectively.
`
`000008
`
`000008
`
`

`

`US 2001/0024353 A1
`
`Sep. 27, 2001
`
`[0041] Although a number of embodiments of the inven-
`tion have been described,
`it should be obvious to those
`skilled in the art that other embodiments to and/or modifi-
`cations, combinations, and substitutions of the present
`invention are possible, all of which are within the scope and
`spirit of the disclosed invention.
`What is claimed is:
`
`1. Alow inductance device for storing an electrical charge
`comprising a capacitor having a plurality of extended elec-
`trodes, wherein electrical current passing through each
`extended electrode from said plurality of extended elec-
`trodes flows in a direction opposite of current passing
`through one or more adjacent extended electrodes of said
`plurality of extended electrodes to provide cancellation of
`inductancc in the device.
`2. The device as recited in claim 1, wherein each extended
`electrode is in parallel with one or more adjacent extended
`electrodes.
`3. The device as recited in claim 1, wherein the device
`further comprises a positive conductor terminal and a nega-
`tive conductor terminal, wherein the negative conductor
`terminal is joined to each of the extended electrodes at a first
`end spray and the positive conductor terminal is joined to
`each of the extended electrodes at a second end spray so that
`the end sprays of adjacent extended electrodes are joined to
`the negative conductor terminal and the positive conductor
`terminal alternately so that current flows in opposite direc-
`tions between first and second end sprays of adjacent
`extended electrodes.
`
`4. The device as recited in claim 3, wherein an insulating
`film separates the positive conductor terminal from the
`negative conductor terminal to produce a conductor-insulat-
`ing film-conductor sandwich.
`5. The device as recited in claim 4, wherein the insulating
`film is wider and longer in dimension than either of the
`positive and negative conductor terminals.
`6. The device as recited in claim 3, wherein the positive
`and the negative conductor terminals are about 3A inch wide
`and between about 5 and 20 mils thick.
`7. The device as recited in claim 4, wherein the conductor-
`insulating film-conductor sandwich is disposed so as to
`substantially surround the plurality of extended electrodes.
`8. The device as recited in claim 4, wherein the conductor-
`insulating film-conductor sandwich is disposed substantially
`beneath the plurality of extended electrodes.
`9. The device as recited in claim 3, wherein end sprays are
`joined to positive conductor terminals using an extension
`spot weld.
`10. The device as recited in claim 3, wherein end sprays
`are joined to negative conductor terminals using soldering
`techniques.
`11. The device as recited in claim 1, wherein the device
`further comprises an insulating film collar that is disposed
`about a first end spray and a second end spray of each of the
`plurality of extended electrodes to further minimize induc-
`tancc.
`
`12. The device as recited in claim 11, wherein the insu-
`lating film collar is about 5/3 inch wide and about 3 mils
`thick.
`
`13. The device as recited in claim 3, wherein a central
`interconnect is disposed centrally within each of the plural-
`ity of extended electrodes that are disposed in series,
`wherein the central interconnect of each of the plurality of
`extended electrodes in series are interconnected by a com-
`mon interconnect to provide cancellation of inductance in
`the device.
`14. The device as recited in claim 13, wherein the
`common interconnect is disposed substantially above the
`negative conductor terminal, wherein an insulating film is
`further disposed between the common interconnect and the
`negative conductor terminal.
`15. The device as recited in claim 13, wherein the
`common interconnect is disposed substantially below the
`negative conductor terminal, wherein an insulating film is
`further disposed between the common interconnect and the
`negative conductor terminal.
`16. The device as recited in claim 3, wherein a central
`intcrconncct is disposed ccntrally within each of the plural-
`ity of extended electrodes that are disposed in series,
`wherein the central interconnect of each of the plurality of
`extended electrodes in series are interconnected by a com-
`mon interconnect to provide cancellation of inductance in
`the device.
`17. Amethod of reducing the inductance of a device used
`for storing an electrical charge, the device having a plurality
`of extended electrodes having a first end spray and a second
`end spray, the method comprising the steps of:
`
`sandwiching an insulating film between a positive con-
`ductor terminal and a negative conductor terminal, and
`
`joining said negative conductor terminal to each of the
`plurality of extended electrodes at a first end spray and
`said positive conductor terminal to each of the plurality
`of extended electrodes at a second end spray so that the
`end sprays of adjacent extended electrodes are joined to
`the negative conductor terminal and the positive con-
`ductor terminal alternately so that current flows in
`opposite directions between first and second end sprays
`of adjacent extended electrodes.
`18. The method as recited in claim 17, wherein the
`method further comprises the steps of:
`
`disposing an insulated central interconnect centrally in
`each of the plurality of extended electrodes in series so
`that current flows in said insulated central interconnect
`
`in an opposite direction to current flowing between the
`first and second end spray of each extended electrode
`sections to provide cancellation of inductance in the
`device; and
`
`joining said insulated central interconnects using a com-
`mon interconnect.
`
`19. The method as recited in claim 17, wherein end sprays
`are joined to the negative conductor terminal by soldering.
`20. The method as recited in claim 17, wherein end sprays
`are joined to the positive conductor terminal using extension
`spot welds.
`
`000009
`
`000009
`
`