Chemistry: electrical current producing apparatus – product – and – Means externally releasing internal gas pressure from closed... – Blowout type
Reexamination Certificate
2001-10-30
2004-03-09
Ryan, Patrick (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Means externally releasing internal gas pressure from closed...
Blowout type
C429S053000, C429S055000
Reexamination Certificate
active
06703157
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a cylindrical battery, such as an alkaline battery or a lithium battery, in which power generating elements are accommodated in a cylindrical battery case and an opening of the battery case is sealed with a sealing member, as well as to a method for manufacturing such a cylindrical battery.
BACKGROUND ART
In alkaline batteries having zinc as the anode active material, there is a fear that a gas is produced inside the battery, due to the wrong charge or the corrosion of zinc, so as to increase the internal pressure of the battery and even lead to an explosion of the battery. The alkaline batteries thus generally have a burst-proof mechanism, which functions in response to an increase in internal pressure of the battery to avoid a possible explosion.
The principle of the burst-proof mechanism is to intentionally break a specific part of lowered mechanical strength, which is a portion of a sealing member to seal the opening of the battery, on the occasion of an increase in internal pressure of the battery, so as to forcibly discharge the gas outside the battery and thereby prevent the battery from being exploded.
A typical alkaline battery having a prior art burst-proof mechanism is described with FIG.
5
.
A battery case
21
keeps therein a cathode mixture
22
, a separator
23
, and an anode
24
as power generating elements. An upper opening of the battery case
21
has a stepped portion
25
, which is bent inward by an external grooving process. A sealing member
29
of a synthetic resin,
1
for example, nylon, is used to seal the opening of the battery case
21
, and includes an inner tubular member
30
that supports an anode collector
28
, an outer tubular member
32
that is clamped by the opening end of the battery case
21
, and a joint member
31
that joins the inner tubular member
30
with the outer tubular member
32
. The joint member
31
has a thin wall portion
34
. A metal washer
26
having a center through hole, in which the inner tubular member
30
is fitted, and an outer circumferential portion of an anode terminal plate
33
are fitted in the outer tubular member
32
of the sealing member
29
. The opening end of the battery case
21
is caulked, so that the metal washer
26
and the outer circumferential portion of the anode terminal plate
33
are securely held by the outer tubular member
32
. The securely held portion is fixed on the stepped portion
25
of the battery case
21
.
When the internal pressure of the battery excessively increases, the thin wall portion
34
of the sealing member
29
is broken, and the gas flowing through this broken portion is discharged outside via through holes
26
a
and
33
a
respectively formed in the metal washer
26
and the anode terminal plate
33
.
As clearly understood from
FIG. 5
, the prior art burst-proof mechanism has a rather complicated structure and located inside the battery. The space required for the burst-proof mechanism sacrifices the capacity for the power generating elements.
Once this burst-proof mechanism functions to break the thin wall portion
34
of the sealing member
29
, an electrolyte leaks through the opening of the broken portion. The opening is not closed and the leakage continues. After the release of the gas, even the dischargeable battery can thus not be used any longer.
In a high temperature environment of or over 60° C., the thin wall portion of the sealing member stretches not to be broken. This accordingly does not work as the burst-proof mechanism, and may lead to an explosion of the battery.
The primary object of the present invention is thus to provide a cylindrical battery having a burst-proof mechanism that does not sacrifice the space for power generating elements but increases the total capacity for power generating elements.
Another object of the present invention is also to provide a cylindrical battery that is continuously usable by shielding the inside of the battery from the outside again after the burst-proof mechanism functions to release the gas from the inside of the battery.
DISCLOSURE OF INVENTION
The primary object of the present invention is attained by a cylindrical battery that includes a battery case, in which power generating elements are accommodated, a sealing member that seals an opening of the battery case, and a circular groove that is disposed in the vicinity of the opening of the battery case and has a bottom bent inward the battery case, wherein the bottom of the groove has at least one gas discharge aperture that is sealed with a seal element.
The primary object and another object of the present invention are attained by a cylindrical battery that includes a battery case, in which power generating elements are accommodated, a sealing member that seals an opening of the battery case, and a circular groove that is disposed in the vicinity of the opening of the battery case and has a bottom bent inward the battery case, wherein the bottom of the groove has at least one gas discharge aperture that is sealed with an elastic ring set in the groove.
REFERENCES:
patent: 2595963 (1952-05-01), Lewis et al.
patent: 3256117 (1966-06-01), Howatt et al.
patent: 3970478 (1976-07-01), Jurva
patent: 5042675 (1991-08-01), Patterson
patent: 624066 (1935-12-01), None
patent: 857987 (1953-03-01), None
patent: 2424428 (1975-12-01), None
patent: 4014945 (1991-11-01), None
patent: 617756 (1949-02-01), None
patent: 62-5558 (1987-01-01), None
patent: 8-31397 (1996-02-01), None
Kubo Isao
Mototani Yuji
Shoji Yasuhiko
Yamamoto Kenji
Dove Tracy
McDermott & Will & Emery
Ryan Patrick
LandOfFree
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