Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1999-05-17
2001-03-13
Shaw, Clifford C. (Department: 1725)
Metal working
Method of mechanical manufacture
Electrical device making
C029S002000, C429S231950, C429S245000
Reexamination Certificate
active
06200356
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a high energy rechargeable battery, and more specifically to a rechargeable lithium ion battery having a carbon anode. The invention relates even more specifically to a method of preventing the electrochemical dissolution of a copper current collector in the lithium ion battery electrolyte.
2. Discussion of the Prior Art
In a lithium ion battery, the metallic lithium anode is replaced with a lithium intercalation host, which is usually a carbonaceous material. One conventional method for fabricating such an anode employs a slurry of carbonaceous material with a binder solution. Examples of the binder solution include a 5 wt. % PTFE (TEFLON) emulsion; a 2.86 wt. % polyvinylidene fluoride solution in 50:50 1-methyl-2-pyrrolidinine and tetrahydrofuran; or a 2 wt. % aqueous 2-hydroxy ethyl cellulose solution. After the slurry has been spread on an electrolytic copper foil current collector, the electrode is vacuum dried at about 120° C.
A problem associated with such carbon electrodes, however, is that copper metal has been found to dissolve in the battery electrolyte and then deposit at the positive electrode, resulting in premature cell failure.
Therefore, a general need exists to provide a lithium ion battery comprising an electrolyte in which copper is not susceptible to electrochemical dissolution. An even more specific need exists to provide a method of preventing the dissolution of a copper current collector in a rechargeable lithium ion battery having a carbon anode.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a lithium ion secondary electrochemical cell comprising an electrolyte in which copper is not susceptible to electrochemical dissolution. It is a further object of the present invention to provide a method of preventing the electrochemical dissolution of a copper current collector in a lithium ion battery electrolyte.
Accordingly, the present invention advantageously relates to a lithium ion secondary electrochemical cell comprising an anode comprising both a material capable of reversibly incorporating an alkali metal, and a copper current collector, a cathode capable of reversibly incorporating an alkali metal, and an electrolyte comprising a solution of an alkali metal salt dissolved in a polar organic solvent.
The present invention further relates to a method of charging the lithium ion cell immediately after its assembly.
The primary advantage associated with the present cell and method is that by immediately charging the freshly assembled lithium ion cell, lithium will be intercalated into carbon. The copper current collector, therefore, will be at the lithium-carbon potential and thus will be cathodically protected, and will not electrochemically dissolve in the lithium ion battery electrolyte.
REFERENCES:
patent: 5053297 (1991-10-01), Yamahira et al.
patent: 5262254 (1993-11-01), Koksbang et al.
patent: 5340368 (1994-08-01), Koksbang et al.
patent: 5561006 (1996-10-01), Lecerf et al.
patent: 5643695 (1997-07-01), Barker et al.
patent: 5670277 (1997-09-01), Barker et al.
patent: 5712059 (1998-01-01), Barker et al.
patent: 5744265 (1998-04-01), Barker et al.
patent: 5882218 (1999-03-01), Reimers
patent: 6048645 (2000-04-01), Saidi et al.
Behl Wishvender K.
Foster Donald
Wolfenstine Jeffrey
Biffoni U. John
Clohan, Jr. Paul S.
Shaw Clifford C.
Stoner Kiley
The United States of America as represented by the Secretary of
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