Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Electrode
Patent
1994-11-21
1997-10-14
Willis, Jr., Prince
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Electrode
4234471, 4234472, H01M 436
Patent
active
056770847
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an electrode using carbon fibers and a chargeable/dischargeable secondary battery using the same.
BACKGROUND ART
In recent years, small secondary batteries having high capacitance have been remarkably demanded with the spread of portable devices such as video cameras and notebook-type personal computers. Most of the secondary batteries currently used are nickel-cadmium batteries which use alkaline electrolytic solutions. Such secondary batteries, however, show low battery voltages of about 1.2 V, and therefore are difficult to be improved in energy density. Under these circumstances, it has been investigated the high energy-type secondary batteries using lithium metal, which is the basest metal, for negative electrode.
However, the secondary batteries in which lithium metal is used for negative electrode have disadvantages such that the lithium develops to dendrites by the (re)charging/discharging cycle, which may cause a short circuit and further cause the danger of ignition of the batteries. In addition, as lithium metal used in a secondary battery is very active, such a battery itself involves highly dangerous factors. Therefore, they are questionable in domestic applicability. In order to solve the problems relating to safety described above, lithium ion secondary batteries using various carbonaceous materials have been proposed recently, by which high energy inherent to the lithium electrode can be given. The secondary batteries of this type are devised by utilizing the phenomenon that, since the carbonaceous material doped with lithium ions at charging comes to have the same electric potential as metal lithium, the carbonaceous material doped with lithium ions can be used for negative electrode in place of metal lithium. In this type of secondary battery, when discharged, the lithium ions which have been doped to the carbonaceous material are dedoped from the negative electrode and go back to the carbonaceous material to which the lithium ions have been doped originally. Therefore, the use of carbonaceous material doped with lithium ions for negative electrode never causes the problem of dendrite production, and furthermore gives excellent safety since metal lithium is not present; therefore has now been investigated extensively.
As the secondary batteries utilizing the doping of lithium ions to carbonaceous material, those have been known, for example, disclosed in Japanese Patent Application Laid-open Nos. 90863/1987 and 122066/1987. The carbonaceous materials used in the references above are generally in a form of powder, and therefore is required to be incorporated with a polymer as a binder such as Teflon and poly(vinylidene fluoride) for molding into an electrode. That is, an electrode can be prepared in the manner that a powdery carbonaceous material is mixed with a binder and then adhered to a metal mesh, or applied on a metal foil as a slurry. On the contrary, as for carbon fibers, there has been no precedent in which carbon fibers are practically used for electrodes of secondary batteries industrially. Therefore, the form or structure of electrode to be preferably employed or the preparation technique of such electrode has been quite unknown. In particular, the most serious technical problems are how to shape carbon fibers into an electrode, how to take the electrical contact of the carbon fiber with a current collector, how to solve a problem of electrical short circuit between a positive electrode and a negative electrode caused by the penetration of fluffs of the carbon fibers through a separator, and so on.
However, when carbon fibers are used in a form of non-woven fabric or woven fabric, the electrode can be prepared without or, if any, a trace amount of a binder. In addition, it is recognized that the use of carbon fibers for electrode is excellent with respect to chemical stability against electrolytes, structural stability against volume expansion caused by doping, cyclicity of (re)charging and discharging, and so on. As the seco
REFERENCES:
patent: 3853610 (1974-12-01), Byrne et al.
patent: 3886386 (1975-05-01), Hillig
patent: 4046663 (1977-09-01), Fleet et al.
patent: 4064330 (1977-12-01), Gaines, Jr. et al.
patent: 4510216 (1985-04-01), Nogami et al.
patent: 4855122 (1989-08-01), Kitamura et al.
patent: 4861575 (1989-08-01), Levan
patent: 4865931 (1989-09-01), McCullough et al.
patent: 5080963 (1992-01-01), Totarchuk et al.
patent: 5093216 (1992-03-01), Azuma et al.
patent: 5158843 (1992-10-01), Batson et al.
patent: 5225296 (1993-07-01), Ohsawa et al.
Kidai Masayuki
Nakae Takeji
Nii Mikio
Suzuki Tatsuhiko
Tsukamoto Jun
Chaney Carol
Toray Industries Inc.
Willis Jr. Prince
LandOfFree
Electrode and secondary battery using 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 Electrode and secondary battery using the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrode and secondary battery using the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1553750