Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Include electrolyte chemically specified and method
Patent
1989-09-22
1991-12-31
Skapars, Anthony
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Include electrolyte chemically specified and method
429219, 429222, 429223, 429224, H01M 1024
Patent
active
050771515
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an alkaline storage battery, a process for preparing the same, and a method of charging the battery.
BACKGROUND ART
As storage batteries, there are presently being mainly used lead batteries and nickel-cadmium batteries, although silver oxide-zinc batteries are also being used to some extent.
Recently, development of a new storage battery has been expected in relation to the miniaturization and weight reduction of electronic machines and apparatus.
The nickel-cadmium battery now in use usually employs for its positive electrode an active material having a cobalt content of from 2 to 10 wt%. On the other hand, employed as its negative electrode is a sintered nickel substrate having a porosity of about 80%, or a plate prepared by fixing cadmium hydroxide and metallic cadmium as active materials on a nickel-plated perforated steel. When this conventional nickel-cadmium battery is charged, the charging should be carried out so as to apply an electric current in an amount corresponding to 105 to 150% of its charge capacity. This is because oxygen is apt to generate during charge, and this lowers the charge efficiency of the positive electrode, resulting in a low Coulomb efficiency. That is, the conventional nickel-cadmium battery has a drawback that its capacity is recovered only when the charging is performed so as to overcharge it. This means that the conventional nickel-cadmium battery should be overcharged while oxygen is being allowed to evolve from the positive electrode. In the nickel-cadmium battery, the oxygen which has evolved from the positive electrode as a result of the reaction shown by equation (1) is absorbed on the negative plate as shown by equation (2).
Therefore, even in the overcharge region, hydrogen does not evolve from the negative electrode and the oxygen generated from the positive electrode is absorbed on the negative electrode, resulting only in heat generation. For this reason, the charging of a nickel-cadmium battery is performed with a constant current by means of a method in which the charging is stopped after an increase in temperature of the battery due to the heat generated in the overcharge region is detected with a thermistor or the like, a method in which the charging is stopped after a phenomenon wherein a decrease in charging voltage occurs due to gas absorption is detected, or a method in which the charging is stopped after an increase in inner pressure is detected with a pressure sensor. In order to perform quick charge according to this charging method, the gas-absorbing performance in the overcharge region should be improved. Since the rate constant for this gas absorption is in proportion to the partial pressure of oxygen, a cylindrical battery is preferably subjected to quick charge because a cylindrical battery case is difficult to suffer from deformation or breakage even if the inner pressure of the battery increases. Even in this case, charging at 1C is the limit. On the other hand, .from the viewpoint of energy density rectangular battery is more advantageous than a cylindrical one. However, since the withstand pressure of the rectangular battery case is lower than that of the cylindrical battery case, its withstand pressure is about 5 kg/cm.sup.2 at most even if a metal such as iron, etc. is employed as the material for the case. Hence, charging at 0.3 C is the maximum limit. As a method of charging this nickel-cadmium battery, there may be mentioned a method in which an increase in charging voltage is detected, but the value is 100 to 150 mV at most. Further, since the increase in voltage becomes small as the temperature increases, not only it becomes necessary to make temperature corrections, but also the method is not so reliable. Furthermore, in the case of constant-voltage charging, a so-called runaway phenomenon is produced, leading to breakage of batteries in some cases.
Moreover, the active materials of negative electrode for sealed-type batteries currently in use have a means for preventing the evolu
REFERENCES:
patent: 3057942 (1962-10-01), Smith et al.
patent: 3089913 (1963-05-01), Garten et al.
patent: 3170819 (1965-02-01), Abramson
patent: 3951686 (1976-04-01), Ness et al.
patent: 4520087 (1985-08-01), Kamata et al.
patent: 4897323 (1990-01-01), Hennrich et al.
Yasuda Hideo
Yoshimura Kozi
Japan Storage Battery Co., Ltd.
Skapars Anthony
LandOfFree
Alkaline storage battery and process for preparing the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Alkaline storage battery and process for preparing the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Alkaline storage battery and process for preparing the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1509400