Chemistry: electrical current producing apparatus – product – and – Having magnetic field feature
Reexamination Certificate
1998-12-01
2001-02-27
Chaney, Carol (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Having magnetic field feature
C429S007000
Reexamination Certificate
active
06194093
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
In a broad aspect, the field of the invention is that of methods for provision of magnetized ferromagnetic components in an electrochemical apparatus wherein current-producing galvanic reactions are enhanced by means of the influence of magnetic fields established within the apparatus by the magnetized ferromagnetic components.
The present invention relates with special pertinence to battery electrodes which magnetically enhance the galvanic reaction in batteries energizing an external circuit in which current demand from an electrical load, such as a motor, tends to manifest discontinuities including high demand at unscheduled intervals.
The present inventor has been specifically engaged in investigation of internal battery structure modifications aimed at improved performance of battery-powered touring vehicles, such as the one testdriven by himself for the University of Victoria Electric Car Research Project, in British Columbia, the Canadian province with more mountain roads and wind than any other. The magnetized current collectors for batteries which he has devised have originated in response to the problem of transient decline in withdrawable current capacity of a battery, which is caused by discontinuous high electrical demands which arise, exascerbatingly, in circumstances inherently likely to occur when one attempts to tour, in a battery-powered vehicle, mountain roads of intermittently steep grade. Even when the road grade is flat, an electric vehicle's progress can be impeded by high headwinds. Highly variable external conditions in the service environment, in other words, translate into highly variable load demand, creating the ensuing capacity withdrawal limitation problem to which the present invention is chiefly directed.
The problem had in the past cast a shadow of doubt on the viability of lead-acid storage batteries for powering high performance road vehicles suitable for mountain touring.
Electrochemistry of the lead-acid storage battery entails that it has maximum capacity for discharge at constant low rate of current withdrawal. In this regard, and notwithstanding that the lead-acid battery is categorized a secondary battery, it is fairly representative of a wide variety of galvanic cells and batteries, both secondary and primary. In other words, there is no surprise that the suggested modification of the lead-acid battery which has recently been devised with the aim of minimizing impairment of electrode function in discontinuous high drain conditions should be found applicable to both primary and secondary cells and batteries—noting, however, that this is an eventuality which would not have been expected if the chief problem addressed by the inventor ‘this time around’ concerned the electrolysis reaction involved in recharging of secondary batteries.
2. Description of Related Art
In practice, no real solid-state electrodes are atomically smooth, without asperities and/or a degree of porosity. Plate electrodes in lead-acid batteries are intentionally fabricated to have a degree of porosity providing electroactive surface areas several orders of magnitude larger than would be apparent from measurement of the plates' exterior planar dimensions.
Underutilization of the whole electroactive surface area, and an attending drop in withdrawable current capacity in high-load conditions, is associated with reduction of ‘penetration depth’ into such plates to which needed ionic reactant entities can reach. Details of what happens are examined in a passage headed “ELECTROCHEMICAL KINETICS OF POROUS ELECTRODES”, pages 151-159 in
Lead
-
Acid Batteries,
by H. Bode, (Wiley-Interscience, 1977).
An important early event in a too-high power demand condition is a kind of internal scavenging of reactant obtained not from the region of electrolyte between spaced-apart electrode plates but rather from electrolyte already internally present in pore networks. Consequent to this event, if the high load persists, is confinement of vital electron-transferring galvanic reactions to as little as only about half the number of possible reaction sites provided by the electrodes. While apparently regarding as impractical extra apparatus for solving this problem, Dr. Bode nonetheless acknowledges applicability of pumps to solving it, stating (last paragraph, p. 155):
“If a flow of electrolyte through the electrode is brought about by external forces, the diffusion-limited depth of penetration vanishes. Then, even on the high current loading, a capacity may be removed that approaches the maximum for long time discharges.”
This statement reflects awareness of proposals for solving electrolyte transport difficulties by use of means such as the propellor, the rotating electrode, the gas bubbler, and the ultrasonic vibrator, which are depicted by Fig. 4.4 on page 130 of
Electrochemical Science,
J. O'M. Bockris and D. Drazic, (Barnes & Noble, 1972). More so than the other means, it seems, the ultrasonic vibrator has invited close comparison with use of magnetic means to stir electrolyte, to thin diffusion layers, to reduce electrical resistance, to minimize concentration over-potential, and even to promote smooth morphology of metal electrodeposited onto negative electrodes of electrolysis devices.
In a conclusory remark in their paper, “Electrothinning and Electrodeposition of Metals in Magnetic Fields”,
Journal of the Electrochemical Society,
119, pp. 51-56, (1972), J. Dash and W. W. King observe:
“Thus, if further research proves that magnetic fields are as effective as ultrasonic fields in improving electrodeposition and other important electrolytic processes, it would appear that the former have appreciable economic advantages.”
A host of similarly directed observations may be retrieved from publications of workers in a subdivision of electrochemical research that has come to be called ‘magnetoelectrolysis’. Such research focusses on the effects of superposed magnetic fields upon electrolysis reactions in laboratory apparatus powered by current from some easily regulated source.
A sharp focus instead on magnetic field influence on galvanic reactions supplying current to a randomly variable external load would conceivably characterize a type of research for which the designation ‘magnetogalvanics’ would be apt; however, because neither this term nor the focus thereby connoted seems yet to be retrievable from electrochemical research literature, findings in magnetoelectrolysis meanwhile provide useful background to the present invention. Reference is suggested to a review of magnetoelectrolysis issues provided by the present inventor, R. N. O'Brien, and a former colleague, K. S. V. Santhanam, in a passage entitled “MAGNETIC FIELD EFFECT ON ELECTRODEPOSITION”, pages 453-464 in
Techniques for Characterization of Electrodes and Electrochemical Processes,
eds. R. Varma and J. R. Selman, (Wiley-Interscience, 1991). The present inventor's work making magnetoelectrolysis effects visually interpretable by means of laser interferometry have been cited in an overview article entitled “Applications of Magnetoelectrolysis”, by R. A. Tacken and L. J. J. Janssen,
Journal of Applied Electrochemistry.,
25, 1 (1995).
Although there apparently have not been reports in journal literature which describe magnetic field effects on galvanic reactions, as distinct from effects on electrolysis, this lack is counterbalanced to some extent by descriptions appearing in two highly pertinent United States patents:
U.S. Pat. No. 3,597,278 (Aug. 3, 1971), ELECTROLYTIC CELL COMPRISING MEANS FOR CREATING A MAGNETIC FIELD WITHIN THE CELL, J. W. Von Brimer; and,
U.S. Pat. No. 5,051,157 (Sep. 24, 1991), SPACER FOR AN ELECTROCHEMICAL APPARATUS, R. N. O'Brien and K. S. V. Santhanam.
These are believed to constitute close prior art because both disclosures refer to use of permanent magnets integral with the construction of a modified lead-acid storage battery, and in both citations, at certain points, description of a magnetic field effec
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