Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Cell enclosure structure – e.g. – housing – casing – container,...
Reexamination Certificate
1999-05-20
2001-03-27
Kalafut, Stephen (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Cell enclosure structure, e.g., housing, casing, container,...
C429S175000, C429S185000, C429S163000, C429S007000, C429S061000, C429S062000, C429S082000, C429S053000, C429S056000
Reexamination Certificate
active
06207320
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a secondary battery and, more particularly, to a cap assembly of a secondary battery, which is designed to seal the battery housing more effectively and thus prevent electrolyte from leaking.
2. Description of Related Art
Generally, secondary batteries are made compact in size and rechargeable, and yet have a large capacity. Well known as secondary batteries are a Ni—MH battery, a Li battery, and a Li-ion battery.
Particularly, the Li-ion battery uses lithium metal oxide as a positive active material and carbon or a carbon compound as a negative active material. An organic solvent in which lithium salt is dissolved is used as the electrolyte via which the lithium ions move between positive and negative electrodes. Batteries are charged and discharged as the lithium ions are moved between positive and negative electrodes.
FIG. 4
shows a conventional Li-ion battery.
A rolled electrode assembly
2
is inserted into a can
4
filled with electrolyte, the rolled electrode assembly
2
comprising of positive and negative electrodes and a separator disposed between the positive and negative electrodes. Mounted on an upper end of the can
4
is a cap assembly
6
.
The cap assembly
6
is insulated from the can
4
by a gasket
8
. That is, the upper end of the can
4
is crimped on an outer periphery of the cap assembly
6
with the gasket
8
in between. The cap assembly
6
comprises a plate
14
provided with a safety groove, a current control member
12
disposed on the plate
14
, and a cap cover
10
disposed on the current control member
12
. Attached under the plate
14
is a circuit breaker
18
with an insulator
16
disposed therebetween. The insulator
16
is supported by a support plate
17
, which is designed to maintain its attaching state even when the circuit breaker
18
is detached from the plate
14
.
The circuit breaker
18
is welded on a positive lead
20
so that it is electrically coupled to a positive electrode of the electrode assembly
2
.
In the conventional Li-ion battery structured as described above, to enhance airtightness and prevent the electrolyte from leaking, the gasket
8
is designed to be compressed by a predetermined level of pressure. However, if the gasket
8
is mis-assembled, the degree of airtightness may degrade, thereby allowing the electrolyte to leak.
Particularly, in the case of a cylindrical Li-ion battery, airtightness depends on the contacting area between the plate
14
and the gasket
8
. However, in the conventional battery, the contacting area is insufficient and the housing may be not airtight.
SUMMARY OF THE INVENTION
Therefore, the present invention has been made in an effort to solve the above-described problems.
It is an objective of the present invention to provide a cap assembly of a secondary battery, which can enhance airtightness of the battery housing by providing an enlarged contacting area with a gasket and thus prevent electrolyte leakage.
To achieve the above objective, the present invention provides a cap assembly for a battery comprising a can filled with an electrolyte and an electrode assembly. The cap assembly is close-tightly mounted on an upper end of the can with a gasket interposed between the cap assembly and the upper end of the can. The cap assembly comprises a plate provided with a safety groove, a current control member disposed on the plate, a cap cover disposed on the current control member, and a circuit breaker disposed under the plate and supported by a support plate.
As a feature of the present invention, the circumferential edge of at least one of the plate, the current control member, and the cap cover of the cap assembly is bent around the support plate.
The cap assembly may further comprise an insulator disposed between the plate and the circuit breaker. The insulator is fixed by the support plate.
REFERENCES:
patent: 5609972 (1997-03-01), Kaschmitter et al.
patent: 6215747 (1994-08-01), None
Choi Eung-Kil
Hwang Ea-Joo
Kim Hyoung-Su
Song Man-gon
Baker & McKenzie
Kalafut Stephen
Martin Angela J.
Samsung Display Devices Co. Ltd.
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