U.S. patent application number 10/457377 was filed with the patent office on 2004-12-16 for battery charging method using supercapacitors at two stages.
Invention is credited to O'Brien, Robert Neville.
Application Number | 20040251880 10/457377 |
Document ID | / |
Family ID | 33510445 |
Filed Date | 2004-12-16 |
United States Patent
Application |
20040251880 |
Kind Code |
A1 |
O'Brien, Robert Neville |
December 16, 2004 |
BATTERY CHARGING METHOD USING SUPERCAPACITORS AT TWO STAGES
Abstract
A method for rapidly charging an electrically rechargeable
battery or batteries string by a series of charging pulses,
interspersed with battery discharge pulses effective to eliminate
undesired concentration polarization by substantially thinning or
dispelling electrical double layers and diffusion layers at
electrodes contacted by an aqueous electrolyte solution. In
contrast to related schemes which intermittently discharge a
limited portion of battery charge to a load comprising components
featuring significant resistance and/or inductance, in this case
supercapacitors receive the reversedly pulsed depolarizing
discharge.
Inventors: |
O'Brien, Robert Neville;
(Victoria, CA) |
Correspondence
Address: |
Robert N. O'Brien
2614 Queenswood Drive
Victoria
BC
V8N 1X5
CA
|
Family ID: |
33510445 |
Appl. No.: |
10/457377 |
Filed: |
June 10, 2003 |
Current U.S.
Class: |
320/166 |
Current CPC
Class: |
H02J 7/345 20130101;
H02J 7/0016 20130101; H02J 7/0019 20130101; H02J 7/00711
20200101 |
Class at
Publication: |
320/166 |
International
Class: |
H02J 007/00 |
Claims
What is claimed as new is:
1. In an improved method for rapidly charging an electrically
rechargeable battery or batteries string by a series of charging
pulses, interspersed with battery discharge pulses effective to
eliminate undesired concentration polarization by substantially
thinning or dispelling electrical double layers and diffusion
layers at electrodes contacted by an aqueous electrolyte solution,
the steps of: procuring a first apparatus portion stage essentially
comprising a DC current source, a first stage supercapacitor, and
conductor means having a first switch between said current source
and said first stage supercapacitor, and a second switch between
said first stage supercapacitor and a second apparatus portion
stage; procuring the second apparatus portion stage, essentially
comprising an array of at least three second stage supercapacitors
alternately connectable in series or parallel by means of a set of
associated switches and conductor means, a sensor to detect slope
of a charging pulse from said first apparatus portion stage, and
microprocessor means for governing said associated switches in
suitable accord with data from said sensor; procuring a third
apparatus portion stage essentially comprising a batteries string
of electrical rechargeable batteries, and third stage conductor
means capable of interconnecting said batteries alternately in
series or parallel with one another and with said second stage
supercapacitors in a suitable manner by use of said set of
associated switches; charging said first stage supercapacitor with
electrical energy from said DC current source; discharging said
first stage supercapacitor through said conductor means of said
first stage and thence to said second stage and thereon through to
said third stage; disconnecting said first stage from said second
and third stages remaining in connection with one another while
said first stage supercapacitor is recharged by reconnection to
said DC current source; discharging a limited portion of
accumulated charge from said battery string of said third stage,
back into said supercapacitors array of said second stage; and,
repeating the cycle of discharging to said second and third stages
from said first stage supercapacitor; followed by repeating the
limited discharge from said battery string a number of times which
is one less time than the total number of times said first stage
supercapacitor discharges to complete this method of
recharging.
2. An apparatus comprising the three stages procured for carrying
out the method of recharging of claim 1, wherein both said first
stage supercapacitor and said second stage supercapactors are all
of a type having magnetized parts and which thereby procure short
time constants and low internal resistance due to
magnetohydrodynamic stirring of an electrolyte solution in said
supercapacitors of both the first and second stages.
3. The apparatus of claim 2, wherein capacity of said first stage
supercapacitor is scaled from one-tenth to one-fourth the capacity
of said second stage supercapacitors and third stage rechargeable
batteries in combination.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] Not applicable
STATEMENT RE. FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable
BACKGROUND OF THE INVENTION--TECHNICAL FIELD
[0003] In general, this invention relates to battery chargers, and
more particularly to a method of charging a secondary battery or
string of batteries by the use of pulses of direct current, as
opposed to continuous current, specifically where a repeated step
in enactment of the method involves pulsed discharges of current
taken from the battery or batteries string, interspersing such
discharging pulses between charging pulses. Another aspect of
general pertinence concerns timely switching back and forth between
parallel and series arrangements of circuitry. Types of batteries
chargeable in accordance with the method to be described may
include, but are not confined to, batteries having magnetized
current collectors, such as those described in U.S. Pat. No.
6,194,093 B1 by O'Brien, the same inventor as at present.
BACKGROUND OF THE INVENTION--DESCRIPTION OF RELATED ART
[0004] Descriptions of battery chargers delivering charging current
pulses interspersed by pulsed battery discharges are extant,
including chargers devised to procure depolarization of batteries
by means of the discharges. Such depolarization mitigates adverse
consequences of high current rapid charging, including elevated
internal energy losses, overheating, and gas evolution dangerously
building up pressure within battery casings. In background
discussion for U.S. Pat. No. 4,829,225 by Podrazhansky et al.,
earlier implementation of a reversedly pulsing approach to battery
charging was credited to others, eg., Burkett et al.
[0005] U.S. Pat. No. 4,829,225 particularly teaches "charging a
battery by providing a charge pulse to the battery, followed
immediately by a depolarization pulse created by allowing the
battery to discharge across a load, followed by a stabilization
period, and repeating this sequence cyclically until the battery is
charged." The same patent also suggests that the "discharge load
may be provided by a transistor . . . controlled by the system
control logic . . . to provide a variable resistance." There is no
suggestion by Podrazhansky et al. that the component loaded by
discharge pulses should be a supercapacitor--preferably employing
the new supercapacitors with magnetized parts that O'Brien
describes in U.S. Pat. No. 6,556,424 B2 which is herewith
incorporated by reference.
[0006] In general, one kind of distinction thought helpful for
distinguishing between the reversedly pulsing
(charging/discharging) arrangements of some inventions in this
field, from others, is the distinction concerning the specific type
of component or locally grouped set of components to which
discharge pulses from a battery or batteries string are to be
delivered. Thus, on the point that discharges are delivered to a
variable-resistance transistor for the Podrazhansky et al battery
charger, more of a family resemblance thereto than strong
distinction therefrom is perceptible in the pulsed charger
described in U.S. Pat. No. 5,621,297 by Feldstein, who discloses
means whereby discharge pulses flow through "isolation diodes" to
"discharge current resistors", as and when permitted by
transistorized control. Podrazhansky et al and Feldstein therefore
would likely concur in accepting the inevitable energy losses
associated with delivering battery current to resistors. Acceptance
of degradation of electric energy to heat is not part of the
approach adopted for the present invention, however, albeit also
involves interspersal of battery current discharge pulses between
battery charging pulses.
[0007] Another approach perceptible in the background art is to
locally group inductors and ordinary capacitors in suitably
switched circuitry, so as to use a subset of inductors and
capacitors both to discharge pulses of charging current into a
battery or batteries string, and to intermittently receive pulses
of battery current discharged thereto. This approach seems to use
inductors and capacitors, basically, in substitution for the kind
of use of resistors as has been mentioned above with regard to the
Podrazhansky et al and Feldstein inventions. Both W. Newman in U.S.
Pat. No. 4,016,473 and Pascual et al in U.S. Pat. No. 5,710,504
describe using inductors and capacitors grouped to intermittently
receive delivery of battery discharge pulses.
[0008] When current flowing through an inductor is switched off,
there will of course occur a collapsing magnetic field, causing
dissipation of heat in local conductors, which is as truly an
instance of energy degradation as is that occurring with components
more ostensibly identified as resistors. The difference that
resistors generate heat during the period of time when current is
flowing, whereas inductors generate heat immediately after flowing
current is interrupted, is not of significance to the point
presently made, that the substitution for resistors that appears
adopted by Newman and by Pascual et al incurs energy loss because
of switching off inductors. Moreover, neither Newman nor Pascual et
al specify a requirement that the capacitors they use to both
transmit and receive pulsed current should be supercapacitors, as
specified hereinafter as an essential feature of the present
invention.
[0009] The abovecited Pascual et al. invention, which does not in
every embodiment require using inductors to the same extent Newman
uses them, is ostensibly concerned with an "active equalization"
method whereby batteries in a long string may be equalized. The
inference is not avoidable, however, that an incidental effect of
the method of equalization proposed by Pascual et al. is
depolarization procured in a substantially similar manner as for
the several battery charger patents of the background art.
[0010] The practice of discharging depolarization pulses from a
battery by use of a special charger is applicable to secondary
electrochemical cells of well known types having solid-phase
electroactive materials for anodes and cathodes, in contact with
liquid-phase, usually aqueous, electrolyte solutions, noting that
such cells operate at temperatures below melting points of the
electroactive materials involved. High temperature cells using
electroactive materials such as sodium and sulfur in a molten
flowing state do not incur the identical entire set of problems
addressed by pulsed charging methods, including, for example, the
battery life cycle problem of shedding of electroactive materials
from typical metal electrode grids or current collectors, which can
occur due to the difference in thermal expansion properties between
the grids and/or current collectors on the one hand, and the
electroactive materials on the other hand. The present invention
applies to the same types of batteries as do the background art
inventions, and like them helps prolong battery life cycles by
avoiding the high continuous current method of charging that
exascerbates a tendency of overheated electrode assemblies to shed
electroactive materials.
BRIEF SUMMARY OF THE INVENTION
[0011] Objects of this invention include providing an improved
method and apparatus for rapidly charging an electrically
rechargeable battery or batteries string by a series of charging
pulses, interspersed with battery discharge pulses effective to
eliminate undesired concentration polarization, by substantially
thinning or dispelling electrical double layers and diffusion
layers at electrodes contacted by an aqueous electrolyte solution.
Concurrent objects include prevention of overheating batteries, and
of dangerously built-up pressure from gas evolution. A major
general aim is to conserve energy in the course of enacting
intermittent discharge pulses interspersed with charging pulses. An
important specific object of invention is to effect discharge
pulses in such a manner that electrical energy is not degraded to
heat energy either by dissipation in resistive elements or in
consequence of magnetic field collapses when local currents
suddenly cease. Electrical energy of discharge pulses is to be
stored temporarily in supercapacitors that will experience no
significant heating during their service in accordance with the
method of the invention.
[0012] For a preferred embodiment of the invention, the new
supercapacitors with magnetized parts shall be employed to
advantage; however, supercapacitors such as those to which the
recent invention of supercapacitors with magnetized parts applies
as an improvement will be serviceable in other embodiments, without
necessity of magnetized parts. Regarding the preferred embodiment,
permanent magnet materials for the pertinent parts will have been
pre-selected for ability to withstand predetermined electrical
conditions and current-associated magnetic fields, without
incurring de-magnetization. A preferred embodiment charger,
moreover, is expected to be most effective when the type of battery
charged is one having magnetized current collectors.
[0013] Intermittent charging and discharging of electronic
components is to be performed for three basic sections or
subassemblies of grouped features, nominally referred to
respectively using the terms "first stage", "second stage", and
"third stage", where the key feature of the third stage is a
temporarily emplaced actual battery or batteries string to be
brought up to full charge according to the method of the invention,
and where the key feature of the first stage is a supercapacitor
with a per discharge releasable capacity that may be scaled in
typical instances at from about 10% to 25% of the total amount of
energy stored by the end of the process in both the second and
third stages. The first stage supercapacitor is charged by current
from any suitable DC current source, such as a rectifier drawing
mains AC current, or a generator.
[0014] The abovestated limitation pertaining to capacity of the
first stage supercapacitor logically suggests needing from at least
four to ten charging/discharging cycles of the first stage
supercapacitor, to enact a typical complete battery charging
process very rapidly. Actual practice would not necessarily be
limited to a particular number of first stage discharges, however,
because of variables in sizes and types of battery strings, and
rising costs of larger size supercapacitors, the pseudo-capacitance
procuring materials in which are quite expensive.
[0015] Multiple surges of current to be periodically discharged
from a first stage supercapacitor will be delivered into and
through the array of second stage supercapacitors wherein they are
alternately electrically connectible amongst one another in either
a series or else parallel arrangement, besides being connected
alternately in series or in parallel to the third stage, which in
its instance when several batteries are "stringed" is also variably
internally connected with the batteries in series or parallel,
wholly or partially. Second stage supercapacitors should have
higher energy storage capacities when batteries requiring
relatively more protection from large charging surges are charged,
and may have relatively lower capacities when not so much surge
protection is needed by a particular battery type. An estimated 10%
to 50% of the amount of energy the third stage (battery or
batteries string) will ultimately store may be a suitable second
stage capacity, but again the size and capacity for supercapacitors
in the second stage may in practice vary for a number of reasons.
It is generally desirable that there should be a possibility, at
conclusion of the process, of storing energy in the second stage
supercapacitors array. For example, assuming enactment of a
complete battery charging procedure that involves ten discharges of
a first stage supercapacitor, the last depolarization pulse of
energy back to the second stage supercapacitors array from the
third stage batteries string may be left stored in the second stage
supercapacitors array for future use of any kind, including
delivery in a manner to be described hereinafter to a load that may
be the same electric motor the charged-up batteries are to
power.
[0016] Regarding series and parallel arrangement alternatives
amongst the second stage supercapacitors, they will have been
electrically connected to one another in series, and in series to
the third stage batteries also in series, just prior to receiving a
surge of energy discharged from the first stage supercapacitor, the
surge feeding both into the second stage supercapacitors array and
a portion thereof passing therethrough to the third stage. The
slope of the energy surge from a first stage discharge should be
detected by a suitable sensor, used to ascertain when the surge
subsides from peak energy transfer.
[0017] Charging pulse surge slope information should be fed to a
microprocessor control unit responsible for switching electrical
connections from series to parallel arrangements. At the same time
the arrayed supercapacitors are in parallel with one another, a
third stage batteries string may have some rather than necessarily
all its batteries changed from series to parallel interconnection,
depending on how close to completion is the overall charging
procedure. During the initial and peak transfer phase of energy
discharged by each pulse from the first stage supercapacitor, the
second stage supercapacitors array operates in a filtering or
smoothing manner, so to speak, which protects the third stage
batteries from deleterious consequences of a sudden power surge,
such as overheating and damage to electrode structure which could
otherwise occur from a similarly strong surge but absent the
intervening second stage supercapacitors. During the lattermost
portion of energy transfer from a particular discharge of the first
stage supercapacitor, parallel interconnecting arrangements can
procure an equalizing effect and reasonable speed and voltage of
charging of the batteries.
[0018] Upon virtual exhaustion of a discharge from the first stage
supercapacitor, this will be sensed by a suitable sensor and a
switch will operate to disconnect the first stage from the
remaining-connected second and third stages. During the period of
its disconnection from them is when the first stage supercapacitor
will be recharged from the DC source, and while this is happening a
portion of the energy already received by the third stage batteries
will be pulsed back into the second stage supercapacitors array in
generally a similar manner as for the known depolarizing pulses in
abovecited background art inventions--with the notable exception
that here the so-called "bucking voltage" energy definitely is not
dissipated in heat-generating components like resistors and/or
inductors, because it will be received and conserved in the
supercapacitors which are the special technical feature of the
second stage.
[0019] During the periods of discharging a pulse of current to the
second stage array of supercapacitors from the third stage
batteries, as many of the latter as are needed to be in a series
mode of arrangement should be switched thereto, in order that the
voltage for their discharge pulse will be well above any voltage
possibly remaining at the time in the second stage supercapacitors
array, which itself should briefly be left in parallel arrangement
for this period of reversed discharging, which is estimated to take
typically from about 10 to 15 seconds. The time needed depends on
how long it takes both for electrical double layers at the battery
and supercapacitor electrodes, and for the diffusion layers
adjacent battery and supercapacitor electrodes, to be dispelled,
thereby, in the instance of the batteries, removing the principal
causes of concentration polarization.
[0020] In the instance of the supercapacitors, reducing the time
constant is effected--in both instances, of magnetically enhanced
batteries and magnetically enhanced supercapacitors, reducing
internal resistance and preventing overheating and gas evolution.
Time for dispelling diffusion layers, which is the slower attained
of the two objectives here, since electrical double layers dispel
more rapidly, is significantly shorter when magnetohydrodynamic
stirring of an electrolyte solution is a present factor. The best
contemplated way to match a shortened depolarizing discharge pulse
period from the batteries is to employ supercapacitors in the
second stage array which themselves feature a magnetically enhanced
electrolyte convection process, by virtue of their having
magnetized parts in accordance with the above cross-referenced
related application, descriptive contents of which are properly
incorporated herewith by reference.
[0021] Any suitable sensing means whereby a determination can be
made that the diffusion layers adjacent battery electrodes have
been dispelled will inform the microprocessor control unit of the
fact, so that appropriate terminal reconnections readying the
second stage for receipt of the next discharge pulse from the first
stage supercapacitor may be made. By way of summary: while the
depolarizing discharge pulse transfer of energy to the second stage
array of supercapacitors from the third stage batteries takes
place, the first stage supercapacitor is being brought up to its
full charge state to ready it for discharge when connected again to
the second stage. That re-connection should not occur until the
second stage supercapacitors have been brought back again into
series arrangement amongst themselves, which is best for absorbing
the initial and peak transfer of energy to and through them. Their
switching back to series may be initiated upon receipt of a
microprocessor control unit of sensed information that a suitable
amount of discharged current from the third stage may be inferred
to have resulted in adequate battery depolarization for the time
being.
[0022] Especially in view of extensive applicable details and
options taught in prior art teachings of pulsed charging methods
wherein it has been known to interperse discharge pulses from
batteries, with charging pulses, now, together with a high level of
skill and knowledge in the field, plus relatively recent
disclosures by R. N. O'Brien (the present inventor) concerning
magnetohydrodynamic stirring to reduce internal resistances of
batteries and supercapacitors, it is considered instantly within
the capabilities of artisans of the field, without need for undue
experiment or necessity to independently discover special
materials, to give engineered effect to the here-suggested present
invention. For greater understanding of the suggestion,
illustration by way of detailed description with reference to a
schematic figure follows.
[0023] In the instance of the supercapacitors, reducing the time
constant is effected--in both instances, of magnetically enhanced
batteries and magnetically enhanced supercapacitors, reducing
internal resistance and preventing overheating and gas evolution.
Time for dispelling diffusion layers, which is the slower attained
of the two objectives here, since electrical double layers dispel
more rapidly, is significantly shorter when magnetohydrodynamic
stirring of an electrolyte solution is a present factor. The best
contemplated way to match a shortened depolarizing discharge pulse
period from the batteries is to employ supercapacitors in the
second stage array which themselves feature a magnetically enhanced
electrolyte convection process, by virtue of their having
magnetized parts in accordance with U.S. Pat. No. 6,556,424 B2 by
O'Brien, incorporated herewith by reference.
[0024] Any suitable sensing medals whereby a determination can be
made that the diffusion layers adjacent battery electrodes have
been dispelled will inform the microprocessor control unit of the
fact, so that appropriate terminal reconnections readying the
second stage for receipt of the next discharge pulse from the first
stage supercapacitor may be made. By way of summary: while the
depolarizing discharge pulse transfer of energy to the second stage
array of supercapacitors from the third stage batteries takes
place, the first stage supercapacitor is being brought up to its
full charge state to ready it for discharge when connected again to
the second stage. That re-connection should not occur until the
second stage supercapacitors have been brought back again into
series arrangement amongst themselves, which is best for absorbing
the initial and peak transfer of energy to and through them. Their
switching back to series may be initiated upon receipt of a
microprocessor control unit of sensed information that a suitable
amount of discharged current from the third stage may be inferred
to have resulted in adequate battery depolarization for the time
being.
[0025] Especially in view of extensive applicable details and
options taught in prior art teachings of pulsed charging methods
wherein it has been known to interperse discharge pulses from
batteries, with charging pulses, now, together with a high level of
skill and knowledge in the field, plus relatively recent
disclosures by R. N. O'Brien (the present inventor) concerning
magnetohydrodynamic stirring to reduce internal resistances of
batteries and supercapacitors, it is considered instantly within
the capabilities of artisans of the field, without need for undue
experiment or necessity to independently discover special
materials, to give engineered effect to the here-suggested present
invention. For greater understanding of the suggestion,
illustration by way of detailed description with reference to a
schematic figure follows.
BRIEF DESCRIPTION OF THE DRAWING
[0026] FIG. 1 is a schematic illustration to assist understanding
how essential steps of the pulsed charging/discharging method of
the invention can be enacted using apparatus elements that are
preferably arranged basically in three stages as suggested.
DETAILED DESCRIPTION OF THE INVENTION
[0027] With reference to the schematics of FIG. 1, certain of the
enumerated figure elements group together as features
representatively of and respectively belonging to each of the three
basic sections or subassemblies referred to in the SUMMARY above
using the terms "first stage", "second stage", and "third
stage".
[0028] Regarding the first stage, generally designated by numeral 1
at the side of a stylized "bracket" having arrowheaded leadlines at
top and bottom, the uppermost feature is a suitable DC current
source 10, an the lowermost feature is conductor means 15 leading
to the second stage. The key special feature of stage 1 is
supercapacitor 14, which is intended to be charged by current drawn
from source 10 through conductor means 13 when on/off switch 12 is
so closed as to pass current through from conductor means 11 below
source 10 in the figure. Switch 12 may be turned on and off in
accordance with a predetermined timing mechanism. Typical per
discharge releasable capacity of supercapacitor 14 may be from
about 10% to 25% of the total amount of energy stored by the end of
the overall charging process in both the second and third stages,
which, although logically suggesting supercapacitor 14 would
typically be charged and then discharged from at least four to ten
times for a complete battery charging process, should not be taken
to mean actual practice and technical definition of the invention
would necessarily be limited to a particular number of stage 1
charge/discharge cycles.
[0029] Regarding the second stage, generally designated by numeral
2 at the side of another stylized "bracket" having arrowheaded
leadlines at top and bottom, the uppermost feature shown here is an
on/off switch 20, which when closed allows current to discharge
through conductor means 15 of stage 1, coming on into stage 2, and
in so doing being subjected to measurement by means of sensor 22
shown on conductor means 21 just below switch 20. As mentioned in
the above SUMMARY, what sensor 21 measures is the changing slope of
the energy surge associated with a given discharge from stage 1
into stage 2.
[0030] Pulse surge slope information should be fed from sensor 22
to a microprocessor control unit, not shown but well within the art
to provide and suitably arrange, and the purpose of which will be
to correctly operate a system of switches yet to be described so
that certain electrical connections shall be changed from series to
parallel arrangements.
[0031] Continuing with regard to stage 2 features, series/parallel
selection switches 24 are shown at various locations on general
stage 2 conductor means 23 whereby a second stage array 25 of at
least three supercapacitors is effectively interposed between stage
3 and surge-discharging supercapacitor 14 of stage 1. By commands
via the microprocessor, supercapacitors 25, which will have been
electrically connected to one another in series just prior to
receiving a surge of energy discharged from first stage
supercapacitor 14, will be re-arranged amongst one another into a
parallel arrangement after the detected peak of a charging pulse
surge, and in other words during the subsiding slope phase of
supercapacitor 14's discharge pulse to and onwardly through them to
stage 3.
[0032] Features of the third stage as illustrated and designated
generally 3 by the numeral beside the corresponding stylized
"bracket" for this stage are associated conductor means 26 and
emplaced batteries string 27 comprising batteries 27a, 27b, and
27c, which are to be brought up to full charge according to the
method of the invention. The batteries of string (or "battery
pack") 27 are, like the supercapacitors of array 25, intended to
also be connectable alternately in series or in parallel within
their stage 3 emplacement, as well as in relation as a set to stage
2; however, and here not shown, there should preferably also be
means for partial series or parallel interconnection among them,
when appropriate, to accomodate the circumstances of voltage needed
for brief depolarizing pulses therefrom, back into the stage 2
supercapacitors array 25, which would not be expected to always
have the same amount of remaining voltage therein when receiving
the discharge pulse from stage 3 batteries string 27 that will
shortly be described, after immediately next reiterating an
important point from the above SUMMARY. During the initial peak
transfer phase of energy discharged by a pulse from stage 1
supercapacitor 14, not only do stage 2 supercapacitors 25 operate
in a manner protecting stage 3 batteries string 27 from overheating
and damage to electrode structure which could otherwise occur as
deleterious consequences of a sudden power surge, but battery
string 27 will have been additionally protected by its own series
arrangement during the peak energy transfer period, after which a
parallel arrangement procures an equalizing effect and reasonable
speed of completing charge acceptance.
[0033] Upon virtual exhaustion of a discharge from supercapacitor
14, sensor 22's detection of the event, via suitable microprocessor
control, should then disconnect stage 1 from the
remaining-connected stages 2 and 3, switch 20 turning off
synchronously with switch 12 turning back on so that supercapacitor
14 will be recharged from DC source 10. It is while this is
happening that a portion of the energy already charged into
batteries string 27 will be pulsed back into supercapacitors array
25, in generally a similar manner as for the wide variety of
pulsing chargers of abovecited and similar background art
inventions--with the notable exception that here the so-called
"bucking voltage" energy definitely is not dissipated in
heat-generating components like resistors and/or inductors, because
it will be received and conserved in the supercapacitors 27 which
constitute the most special technical feature of stage 2.
[0034] Magnitudes and durations of reverse discharge pulses into
array 25 from batteries string 27 should be limited to what is
minimally needed in order to discharge electrical double layers at
battery electrodes and to remove built-up diffusion layers in
electrolyte solution adjacent battery electrodes, thereby
eliminating about 99% of the undesirable concentration
polarization. The period of reversed discharging per pulse is
estimated to typically require from about 10 to 15 seconds,
depending largely on battery drain properties, and therefore of
shorter duration for notably high drain battery types. The exact
time needed may be ascertained either in advance by routine
experimentation, followed by setting of time delay switch controls,
preferably built into the microprocessor unit already mentioned, or
alternatively by the use of any suitable kind of direct or indirect
polarization sensors (not shown) which may appropriately be used to
get real-time data on the prevailing states of polarization of
batteries 27a, b, and c. Furthermore, as would obviously be
apparent to those of skill in the art, there clearly must always
have been a cessation of any depolarizing reversed pulse from stage
3 into stage 2 before any re-commenced pulsed charging from stage 1
will have been permitted, which again is a matter of timing.
VARIANT PHYSICAL APPARATUS EMBODIMENTS
[0035] It will be borne in mind that FIG. 1 merely supplies a
schematic illustration for assistance in understanding how steps of
the method of the invention proceed, viz., briefly: with charge
intermittently passing from stage 1 to and through stage 2 and
onward to stage 3, followed by brief and very limited reverse
charge transfer back to stage 2 from stage 3, before repeating
discharge from the supercapacitor 14 of stage 1.
[0036] Furthermore, what is shown pictorially in the figure should
not be confused with details of a wiring diagram, and, for example,
various "conductor means" shown do not represent individual wires,
nor do their convergences at various spots respecting other figure
elements indicate precisely where particular terminals and/or
terminal leads should be. All such matters of a wiring diagram
and/or actual physical apparatus depiction are herewith
deliberately left to those of skill in the art to flesh out--which
provision is not thought to tax their skills, providing the basic
suggestion of the invention is considered followable by reference
to the description and illustration supplied as above. Yet further,
and importantly also noted, it is not intended that mechanically
permanent affixation of any particular elements to any other(s)
should be considered to have been specified by the description and
illustration here supplied.
[0037] Next, the artisans' attention is drawn to a few readily
viable options respecting actual physical apparatuses which are not
specifically depicted. The emplacement of batteries at stage 3 may
or may not be such as to permit easy removability of batteries from
that stage. There may be, or optionally may not be, easy
disconnectability of stages 2 and 3 from one another, and/or, in
turn, from stage 1, including DC current source 10, which has
already been indicated to be of no specific type. From these points
it is apparent that either in whole or partially, means for
carrying out the method of the invention may equally well be either
portable or stationary. For example, stages 2 and 3 may be integral
with structure of an electric vehicle but they do not have to be.
Were stage 3 alone, with its battery string 27, mounted in an
electric vehicle, the state of the art certainly suffices for the
balance of other stages (2 and 1) to be engineered into an electric
vehicle charging facility wherein obvious expedients for
interconnecting the stages as needed may be practiced. As another
option, particularly if DC current source 10 were desired to be a
combustion engine-powered generator, the whole set of cooperating
stages 1, 2, and 3 could be aboard a vehicle. In other words, the
invention is not to be limited to a particular mode of application,
vehicular or otherwise, nor must it be used at a particular
physical size scale. Sizes of apparatus could vary from small for
handheld tools, other portable equipment such as wireless
communicators or notebook computers, through vehicular size and
upwards to industrial plant installations on land or even possibly
aboard a ship, or perhaps even at a subsea colony. The foregoing
ideas regarding a great variety of possible settings for using the
invention are not especially exceptional by comparison with similar
wide variety of applications proposed by others with related
battery charging schemes.
[0038] What has been lacking in the prior art is inadequate
attention to the wastage of energy accompanying use of resistors,
inductors, and similar solid-state circuitry components that
dissipate heat during normal operation--besides which there has
been no teaching how to use supercapacitors in pulsed-type battery
chargers, whereas the present invention has been described with
reference to the illustrative figure so as to positively enable
suggested use of supercapacitors to achieve the objects of the
invention, with the most preferred supercapacitors being those of
the very new type having magnetized parts. It is now apparent that,
although objects of the invention are generally similar to those
pursued previously by others with varying degrees of success, these
objects will now be attained in a significantly simplified manner
requiring fewer different types of electronic components than
heretofore. Moreover, the rapid charging done without overheating
and/or other causes of possible damage to the batteries is also now
done with minimal degradation of electric energy to heat, thereby
truly qualifying the invention as one pertaining to conservation of
practical energy supplies.
[0039] The advantages associated with using the preferred new type
of supercapacitor having magnetized parts will be evident from
acquaintance with the abovecited incorporated-by-reference United
States patent by O'Brien. Time constants and very low internal
resistance associated with that invention are understood as lending
themselves superbly to enabling better practice of the present
invention than would be feasible otherwise.
[0040] Furthermore, when such or similar supercapacitors used with
the invention are let to retain charge therein after the associated
batteries are fully charged, this means that a motor or other
electrical load may be powered, if desired, with utilization of
current and voltage derived both from batteries and
supercapacitors.
[0041] When using charged supercapacitors to supply additional
power to that from batteries, it will be borne in mind that it
would be prudent to have a switch isolating the types of energy
storage to limit leakage, when both are "on standby" for future
use, since leakage tends to be greater from capacitors than from
batteries. In general, a combined energy package comprising stages
2 and 3 as described above and retained together, especially
wherein supercapacitors of stage 2 may store a quarter or more as
much energy as the batteries, provides a good combination with
special utility in electric vehicle applications.
[0042] Although the invention has been described above with
concise, accurate, and sufficient description by way of
illustration of how principles of the invention should be applied,
it will be understood that references heretofore to details of what
has been suggested, described, and illustrated are not intended to
rule out any unillustrated variations and modifications which may
be produced without undue experimentation while remaining within
the spirit of equivalence to and scope of recited definition of
essential features, per the following limits of the claims.
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