Electricity: battery or capacitor charging or discharging – Battery or cell discharging – With charging
Patent
1997-12-17
1999-05-18
Tso, Edward H.
Electricity: battery or capacitor charging or discharging
Battery or cell discharging
With charging
H01M10/44
Patent
active
059053631
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a method for reducing the internal resistance of rechargeable accumulators, in particular nickel-cadmium accumulators. However, the invention relates also to the application of the method to other types of accumulators (nickel-metallic hydride, lithium ion accumulators and the like). In addition, the invention relates to such accumulators that can be obtained by the inventive method. The term "accumulator" is used throughout the specification and has the same meaning as the more conventional term "battery".
For reducing the capacity of rechargeable accumulators, various methods are known in the state of the art. Most of these methods are based on controlling the charging current or the charging voltage with respect to time and absolute value during the charging operation of the accumulator. Moreover, special discharging devices ensure the complete discharge of the accumulator prior to its recharging.
All these methods and approaches for the treatment of rechargeable accumulators, however, have in common that the accumulators are charged by means of relatively low voltages and currents.
In view of this, the invention is based on the object to increase the capacity of the accumulators per se.
For this purpose, the invention utilizes the surprising finding that it is possible to reduce the internal resistance of accumulators.
According to the invention, the poles of the accumulator are connected with an electrical energy source which is adapted to output an electrical energy of at least the 40-fold product of the absolute value of the short-circuit current and of the absolute value of the nominal voltage of an untreated accumulator. According to a preferred embodiment of the inventive method, the energy source is a d.c. voltage source, the positive terminal of which is connected with the anode of the accumulator and the negative terminal of which is connected with the cathode of the accumulator. It is, however, also possible to reverse the polarity so that the positive terminal is connected with the cathode of the accumulator and the negative terminal is connected with the anode of the accumulator. Alternatively, the energy source can be an a.c. voltage source as well.
According to the invention, the energy source is connected with the accumulator for at least one millisecond.
It is also possible to repeatedly switch the energy source off and on so that the accumulator is supplied several times with electric energy.
The energy source is preferably adapted for an output of at least 1.5 times the short-circuit current and approx. 30 times the nominal voltage of the accumulator. In order to improve the inventive effect, the energy source is adapted for an output of at least 1.5 times the short-circuit current and approx. 40 times the nominal voltage of the accumulator. According to a currently particularly preferred embodiment, the energy source is adapted for an output of at least 60 times the short-circuit current and approx. 40 times the nominal voltage of an accumulator with six individual cells. For a nickel-cadmium accumulator with a nominal voltage of 7.2 V and a short-circuit current of approx. 150 A, this means a d.c. voltage of approx. 300 V at approx. 10 kA.
The energy source is preferably connected with the accumulator for approx. 1 .mu.sec.
The voltage or the current, respectively, can be increased in order to enhance the desired effect of reducing the internal resistance. If problems occur in conjunction with the heating of the accumulator during its treatment, the accumulator can be suitably cooled.
This is preferably done by immersion in a liquid (oil, frigen, liquid nitrogen or the like).
The energy source is preferably connected with the accumulator for at least 2 msec. In addition to the above mentioned cooling of the accumulator in order to avoid an undesired or detrimental heating of the accumulator, the energy source can also be repeatedly switched on and off, thereby dividing the treatment of the accumulator into several time-sequential sections. A pulsed t
REFERENCES:
patent: Re35643 (1997-10-01), Gali
patent: 4829225 (1989-05-01), Podrazhansky
patent: 5063341 (1991-11-01), Gali
Agulla Manuel
Helbing Ralf
GM Racing Modellsportvertrieb GmbH
Tso Edward H.
LandOfFree
Method for reducing the internal resistance of rechargeable batt does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for reducing the internal resistance of rechargeable batt, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for reducing the internal resistance of rechargeable batt will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1761968