Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Cell enclosure structure – e.g. – housing – casing – container,...
Reexamination Certificate
1998-02-25
2001-09-18
Brouillette, Gabrielle (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Cell enclosure structure, e.g., housing, casing, container,...
C429S211000
Reexamination Certificate
active
06291098
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
This invention relates to a thin type electric cell used for reducing the size and weight of a portable electric equipment. More particularly, it relates to an electrode terminal structure thereof.
2. Description of Related Art
Recently, an electric cell has come to play a crucial role industrially as a power source for portable electrical equipments. For reducing the size and the thickness of the equipments, there is raised a demand for the cell to be able to be housed in a limited space in the equipment. For this purpose, a lithium cell having high energy density and high output density is thought to be most appropriate.
On the other hand, for reducing the size and the weight of the equipment, such a cell which is flexible and high in the degree of freedom in morphology, thin in thickness and large-sized in area or which is thin in thickness and small-sized in area, is desired. These requirements, however, cannot be met if a conventional metal can is used as an outer packaging member. In particular, with a moisture-proofing type multi-layered film, comprised of a heat-fusion type high molecular weight film layer and a metal foil layer, a heretically sealed structure can be realized by hot sealing, while the film itself has superior strength and air-tightness. Thus, the moisture-proofing type multi-layered film is promising as a candidate for the outer packaging material for a cell having high degree of freedom in morphology or a thin type cell.
However, in establishing electrical conduction between the electrode and the external terminal in the moisture-proofing type multi-layered film, through an electrode terminal at a sealing opening of the outer packaging material, the thin sealing opening cannot be sealed with a thick metal wire, while a fine metal wire by itself cannot assure sufficient conductivity. The sealing opening can be reduced in thickness, while conductivity can also be provided, if a metal foil is used for the electrode terminal. However, sufficient tightness in adhesion cannot be provided between the heat fusion type high molecular weight film layer and the metal foil (electrode terminal). The result is that application of the slightest stress leads to delamination to render it impossible to maintain air-tightness of the cell.
Thus, with the electrode terminal of a metal wire or a metal foil, satisfactory air-tightness or mechanical strength cannot be achieved. In particular, the lithium cell, for which investigations are proceeding briskly because of the high energy density and high output density, and which has a sufficient moisture-proof construction is required to be high in air-tightness.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a thin type cell having superior air-tightness and mechanical strength.
As a result of our perseverant researches, the present inventors have found that, by using a netted or porous electrically conductive material for the electrode terminals, it becomes possible to improve tight bonding between the moisture-proofing multi-layered film and the electrode terminals.
That is, the present invention provides a thin type cell including a cathode, an anode and an electrolyte, sheathed within a moisture-proofing multi-layered film formed by a high molecular weight film and a metal foil, in which electrode terminals interconnecting electrodes and external terminals are formed of a netted or porous electrically conductive member.
The netted or porous electrically conductor may preferably be one of metal nets, expanded metal, punched metal and aggregates of carbon fibers.
The netted or porous electrically conductor may preferably be one of carbon, nickel, aluminum, copper, tungsten, stainless steel, iron, silver, gold, alloys thereof or metal plated with the above metals or alloys.
In the thin type cell of the present invention, since the electrode terminals are formed of a netted or porous electrically conductive member, the high molecular weight films at the sealing portion, such as the heat fusible high molecular film layer or the adhesive resin, penetrates into the interstices of the electrode terminals to render the electrode terminal and the high molecular film less liable to be delaminated from each other to realize superior air tightness and mechanical strength.
In the thin type cell of the present invention, it is desirable that the opening portion of the moisture-proofing multi-layered film is sealed by the high molecular weight film and that the high molecular weight film passed through by the electrode terminal is thicker than the remaining areas of the sealing portion. For example, a resin piece is desirably applied or otherwise covers the surface of the electrode terminal in register with the sealing portion.
If the portion of the high molecular weight film lying at the sealing portion passed through by the electrode terminal is thicker than other areas of the sealing portion, the electrode terminals (cathode and the anode) can be prevented from shorting due to contact with the metal foil layer.
With the thin type cell of the present invention, in which the electrode terminals are formed by the netted or porous electrically conductive members, the bonding between the electrode terminals and the moisture-proofing multi-layered film can be improved in tightness to assure superior air-tightness and mechanical strength. Moreover, the shorting of the cathode and the anode can be prevented from occurring, as a result of which the service life, long-term storage characteristics and mechanical strength of the cell can be improved to improve the performance and the reliability of the cell.
REFERENCES:
patent: 3607401 (1971-09-01), Halpert et al.
patent: 4092464 (1978-05-01), Dey et al.
patent: 4758482 (1988-07-01), Yamana et al.
patent: 4997732 (1991-03-01), Austin et al.
patent: 5077153 (1991-12-01), Grange-Cossou et al.
patent: 5456813 (1995-10-01), Grange-Cossou et al.
patent: 5591540 (1997-01-01), Louie et al.
patent: 5837397 (1998-11-01), Xing
patent: 0 390 557 A2 (1990-10-01), None
patent: 2 200 068 A (1988-07-01), None
Akashi Hiroyuki
Shibuya Mashio
Bell Boyd & Lloyd LLC
Brouillette Gabrielle
Sony Corporation
Tsang Susy
LandOfFree
Thin type cell having superior air-tightness and mechanical... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thin type cell having superior air-tightness and mechanical..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thin type cell having superior air-tightness and mechanical... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2459856