Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Cell enclosure structure – e.g. – housing – casing – container,...
Reexamination Certificate
1999-04-16
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, C429S057000, C429S176000
Reexamination Certificate
active
06207319
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 for a secondary battery which can enhance a seal effect and prevent electrolyte from leaking.
2. Description of the Prior Art
Generally, secondary batteries are rechargeable and compact in size, and yet has a large capacity. Well known as secondary batteries are a nickel metal hydride battery, a lithium battery, and a lithium ion(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. Lithium salt dissolved in an organic solvent is used as the electrolyte via which the lithium ions move between positive and negative electrodes.
Charging and discharging operations are realized while the lithium ions are moved between positive and negative electrodes.
FIG. 5
shows a conventional Li-ion battery.
A rolled electrode assembly
1
is inserted into a can
12
filled with electrolyte, the rolled electrode assembly
1
consisting of positive and negative electrodes and a separator disposed between the positive and negative electrodes. Mounted on an upper end of the can
12
is a cap assembly
2
.
The cap assembly
2
is insulated from the can
12
by an intermediate gasket
18
. That is, the upper end of the can
12
is crimped on the outer periphery of the cap assembly
2
with the gasket
18
interposed therebetween.
The cap assembly
2
comprises a plate
10
provided with a safety groove
8
, a current control member
6
disposed on the plate
10
, and a cap cover
4
disposed on the current control member
12
. Welded under the central portion of the plate
10
is a circuit breaker
16
with an insulator
14
disposed therebetween. The gasket
18
is down-skirted and crimped under the periphery of the insulator
14
.
The central portion of the plate
10
that is welded to the circuit breaker
16
serves the function of disconnecting a flow of the current when internal pressure of the battery is increased and of discharging gas generated within the battery due to an abnormal chemical reaction.
To realize this, the safety groove
8
, which is mechanically weak, is formed when casting the plate
10
so that, when internal pressure is overly increased, the plate can be broken at a portion where the safety groove
8
is formed.
However, although the upper end of the can
12
is crimped on a periphery of the cap assembly, since tiny gaps may be formed between the parts constituting the cap assembly, the electrolyte may be leaked through the gaps during the charging and discharging operations of the battery.
In addition, the cap assembly
2
is assembled by first forming the plate
10
using a press working process. After forming the plate, the circuit breaker
16
is first welded to the plate
10
, then, after interposing the insulator
14
between the plate
10
and the circuit breaker
16
, down-skirted under the periphery of the insulator
14
. This causes the manufacturing process to be complicated, decreasing productivity.
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 or a secondary battery, which can enhance a seal effect of the battery and be easily assembled to improve manufacturing productivity.
To achieve the above objective, the present invention provides a cap assembly for a secondary battery having a can containing an electrolyte and an electrode assembly, the cap assembly mounted on the upper end of the can with a gasket disposed between the cap assembly and the can.
The cap assembly comprises a cap cover, a current control member disposed under the cap cover, a cap plate disposed under the current control member, a circuit break disk welded on the cap plate, and an insulator disposed between the cap plate and the circuit break disk.
The cap plate is provided with a safety groove and an indented projection outside the safety groove. The projection is tightly disposed between the gasket and the insulator so as to fixedly support the insulator.
The projection exerts more pressure toward the gasket than otherwise so that air-tightness between the cap plate and the upper end of the can. An indention in the projection serves as a guide groove.
According to a feature of the present invention, the projection comprises a ring-shaped projection formed on a bottom surface of the cap plate.
According to another feature of the present invention, the projection comprises a plurality of point projections formed along a circular direction on a bottom surface of the cap plate.
REFERENCES:
patent: 4670362 (1987-06-01), Wiacek et al.
patent: 5080985 (1992-01-01), Wiacek et al.
patent: 6025090 (2000-02-01), Sargeant et al.
patent: 6042967 (2000-03-01), Sargeant et al.
patent: 6127062 (2000-10-01), Sargeant et al.
Alejandro Raymond
Baker & McKenzie
Kalafut Stephen
Samsung Display Devices Co. Ltd.
LandOfFree
Cap assembly for secondary battery does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cap assembly for secondary battery, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cap assembly for secondary battery will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2506310