Electrolysis: processes – compositions used therein – and methods – Electroforming or composition therefor – Sheet – web – wire – or filament
Patent
1998-04-24
2000-11-28
Gorgos, Kathryn
Electrolysis: processes, compositions used therein, and methods
Electroforming or composition therefor
Sheet, web, wire, or filament
C25D 104
Patent
active
061530778
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method of manufacturing a porous electrolytic metal foil and, more particularly, to a method of manufacturing a porous electrolytic metal foil in which when the metal foil is used as a collector of secondary battery, a mixture for electrode can be supported firmly on the collector, and electron transfer reaction can be caused uniformly at the charging/discharging cycle time.
BACKGROUND ART
In recent years, as portable electronic equipment such as video cameras and notebook type computers has widely been used, the demand for small high-capacity secondary batteries has increased as power sources therefor. Most of the secondary batteries now being used are nickel-cadmium batteries containing an alkali electrolyte, the battery voltage thereof being about 1.2 V. For this reason, a nickel-hydrogen battery has received attention as a higher-power battery, and also a lithium battery has been developed.
The nickel-hydrogen battery works with hydrogen used as an active material for negative electrode. The negative electrode thereof is formed by supporting a hydrogen occlusion alloy capable of reversibly occluding/discharging hydrogen on the collector, and the positive electrode is formed by similarly supporting, for example, nickel hydroxide, which is an active material for positive electrode, on the collector.
For example, when a negative electrode of nickel-hydrogen battery is manufactured, predetermined amounts of hydrogen occlusion alloy powder, conductive material powder such as nickel, and binder powder such as polyvinylidene fluoride are mixed to yield a mixed powder, to which, for example, carboxymethyl cellulose solution is added, by which a slurry, which is a mixture for the negative electrode, is prepared. A collector such as a punching Ni sheet with a desirable opening ratio, a Ni foam sheet with a desirable porosity, or a Ni powder sintered body is filled with the slurry. The mixture is supported on the surface of the collector and in the inside voids thereof in a contacting state by sequentially performing drying, rolling, and heat treatment.
When a positive electrode is manufactured, predetermined amounts of nickel hydroxide powder, which is an active material for the positive electrode, and a conductive material such as nickel powder are mixed to yield a mixed powder, to which, a predetermined amount of, for example, carboxymethyl cellulose solution is added, and the whole mixture is agitated into a slurry form, by which a mixture for the positive electrode is prepared. Thereafter, a collector such as a Ni foam sheet is filled with the mixture for the positive electrode. The mixture for the positive electrode is supported on the collector by sequentially drying and rolling it.
Lithium batteries are broadly classified into metallic lithium batteries and lithium ion batteries.
For the metallic lithium battery, the negative electrode is formed of metallic lithium, and the positive electrode is formed by supporting an active material for positive electrode such as LiCoO.sub.2 on a collector. For the lithium ion battery, the positive electrode is formed in the same manner as described above, but the negative electrode is formed by supporting, for example, carbon (C) capable of occluding/discharging lithium ions on a collector.
In the case of the former battery of the batteries of the two types, dendrite recrystallized lithium is deposited on the surface of metallic lithium, which is the negative electrode, during charging, and it grows as the charging/discharging cycle proceeds, so that the battery cycle life is decreased. In the worst case, the grown recrystallized lithium breaks a separator interposed between the positive and negative electrodes, sometimes causing a short circuit.
Thereupon, regarding the lithium battery, the research and development of a lithium ion battery incorporating a negative electrode formed by supporting carbon on the collector is now being carried on. This negative electrode does not present the problem with metallic lithi
REFERENCES:
patent: 2719820 (1955-10-01), Allen
patent: 4073699 (1978-02-01), Hutkin
patent: 4368107 (1983-01-01), Maejima et al.
patent: 4396465 (1983-08-01), Newell
patent: 4537664 (1985-08-01), Novacek
patent: 4684447 (1987-08-01), Murali et al.
patent: 5019221 (1991-05-01), Khalid et al.
patent: 5262040 (1993-11-01), Hardee et al.
patent: 5441627 (1995-08-01), Kato et al.
Akutsu Tsukasa
Ashizawa Koichi
Kato Hitoshi
Circuit Foil Japan Co., Ltd.
Gorgos Kathryn
Smith-Hicks Erica
LandOfFree
Process for preparing porous electrolytic metal foil does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for preparing porous electrolytic metal foil, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for preparing porous electrolytic metal foil will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1721167