Chemistry: electrical current producing apparatus – product – and – Plural concentric or single coiled electrode
Reexamination Certificate
2001-01-19
2003-07-22
Kalafut, Stephen (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Plural concentric or single coiled electrode
C429S054000, C429S082000, C429S164000, C429S185000
Reexamination Certificate
active
06596434
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a cylindrical type alkaline storage battery.
BACKGROUND OF THE INVENTION
There are a variety of cylindrical type storage batteries available at present, and typical ones are a nickel-cadmium storage battery, a nickel-hydrogen storage battery and the like. These batteries are suitable as a power source for small size equipment and are widely used in various kinds of applications such as a portable telephone, a notebook PC and the like. As the equipment using a battery becomes smaller in size, it is required that a cylindrical type alkaline storage battery should be the safer in operation, smaller in size and larger in capacity.
FIG. 5
is a schematic cross-sectional view of a prior art cylindrical type alkaline storage battery D. In
FIG. 5
, the reference symbol D
1
is a sealing plate, reference symbol
1
is a conductive filter, reference symbol la is a gas venting hole located in the center of the filter
1
, reference symbol
2
is a safety valve, reference symbol
4
is an insulating gasket, reference symbol
5
is a metallic case, reference symbol
6
is a belt-shaped positive electrode plate, reference symbol
7
is a belt-shaped negative electrode plate, reference symbol
8
is a separator, reference symbol
9
is a lead tab electrically connecting the positive electrode plate
6
to the filter
1
, reference symbol
10
is a lead tab electrically connecting the negative electrode plate
7
to the inner surface of the case
5
, reference symbol
11
is an insulating ring, reference symbol
14
is a cap-shaped terminal plate of the prior art sealing plate D
1
, reference symbol
14
a
is a top part of the prior art cap-shaped terminal plate
14
and reference symbol
14
b
is a Range of the prior art cap-shaped terminal plate
14
.
As shown in
FIG. 5
, the belt-shaped positive electrode plate
6
and negative electrode plate
7
are wound in a spiral with the separator
8
sandwiched there-between to form a group of electrode plates. The cylindrical type alkaline battery comprises the foregoing group of electrode plates, the metallic case
5
containing the group of electrode plates and the sealing plate D
1
disposed on the top part of the metallic case
5
.
The safety valve
2
is disposed between the cap-shaped terminal plate
14
and the filter
1
so as to close the gas venting hole la and the foregoing filter
1
is bent in such a way as sandwiching the rim of the flange
14
b
and swaged thereto, thereby constituting a single-piece structure of the sealing plate D
1
.
The insulating gasket
4
is disposed between the part of the single-piece structured sealing plate D
1
, where the foregoing swaging has taken place, and the metallic case
5
, and the edge of the metallic case
5
is bent forcefully inward, thereby sealing the metallic case
5
hermetically. A current path between the cap-shaped terminal plate
14
and the filter
1
is secured at the place where the swaging of the filter
1
onto the rim of the sealing plate
14
has taken place. Almost all of an electrolyte, which is not shown in
FIG. 5
, is held within the group of electrode plates.
In the Published Unexamined Japanese Patent Application No. H10-261397, a sealing plate of one-piece design realized by a flange of a cap-shaped terminal plate welded on a filter is disclosed, thereby demonstrating a structure, in which only the filter of the single-piece structured sealing plate is sealed via a gasket disposed between the filter and a metallic case by bending forcefully the edge of the metallic case inward.
In general, a sealing plate of a cylindrical type alkaline storage battery is required to perform such fundamental functions as hermetic sealing of the battery, safe controlling of a battery's internal pressure and forming of a current path for battery's charging/discharging. The amount of active material that creates battery's capacity is limited by the internal volume of a battery case to accommodate the active material and, on the other hand, the sealing plate is a factor responsible for the reduction of the battery's internal volume. In order for the battery's capacity to be increased, therefore, a sealing plate structure which is as simple as possible and causes the smallest reduction to the battery's internal volume is sought, yet, without sacrificing the aforementioned fundamental functions that the battery's sealing plate is expected to fulfill with a high degree of reliability. From this point of view, the prior art sealing plate as described in the above has demonstrated the following problems:
First, the structural design employed in realizing a single-piece sealing plate by sandwiching the rim of the flange
14
b
of the cap-shaped terminal plate
14
between the bent portions of the filter
1
and swaging the metal pieces involved one another not only makes the design of needed component parts complicated but also results in a bulky structure at the swaged segment of the filter
1
due to folding over the edge thereof thereby reducing the battery's internal volume to an intolerable extent and hindering the attempt to increase the battery's capacity.
Next, the structural design employed in realizing another single-piece sealing plate by joining the cap-shaped terminal plate
14
and the filter
1
by welding makes the design of needed component parts complicated in the same way as the above and also results in a loss of the battery's internal volume due to a complicated structure of the safety valve
2
. Furthermore, when break down at the welding point is brought from an inadvertently weak welding in production process or corrosion, vibration and infliction during the use of the battery, the current path can not be secured and further a reduction of reliability in the sealing point is brought about by the breakage of the welded segment since only the side of the filter
1
of the sealing plate D
1
is performing a sealing function between the sealing plate D
1
and the metallic case
5
.
In addition, with a cylindrical type alkaline storage battery, phenomena like excessive current flow are recognized which cause abrupt rise in the internal pressure and leakage of large amount of gas likely when an inappropriate charge circuit is used or a charge circuit is out of order or an inappropriate charging condition is set up. In order to cope with this unusual rise in the internal pressure under abnormal conditions and secure a safe operation of the battery, a safety valve mechanism as shown in
FIG. 5
is usually employed. However, when the aforementioned unusually excessive current flows over a prolonged period, not only a safety control problem caused by a released gas and but also battery performance problems which are caused by drying up of electrolyte and accelerated deterioration of separators due to over heating. In such a case, normal performance is not recovered even if the charge current is returned to the normal level, may be resulted. Therefore, it is required of a sealing plate to include a reversible mechanism whereby the electric circuit is interrupted when an unusually excessive current such as above continues therein and the electric-circuit is preferably recovered when the internal pressure returns to the normal level.
The present invention aims at improving the safety control of the internal pressure and enhances the reliability of the electric current path while achieving a simplification of the mechanism as described above, and, at the same time, maintains the required internal volume of the battery and, further, also aims at realizing a new mechanism whereby interruption of excessive current flows and recovery of the electric current path upon reduction of the internal pressure are made possible.
DISCLOSURE OF THE INVENTION
What is disclosed by the present invention in dealing with the foregoing problems is as follows:
With a cylindrical type alkaline storage battery comprising a group of spirally wound electrode plates formed of belt-shaped positive electrode
Kaiya Hideo
Suzuki Norio
Yoshinaka Takeshi
Alejandro Raymond
Kalafut Stephen
RatnerPrestia
LandOfFree
Cylindrical type alkaline storage 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 Cylindrical type alkaline storage battery, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cylindrical type alkaline storage battery will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3095419