Capacitor

Details Capacitor Capacitor

2000-03-02

2001-10-30

Dinkins, Anthony (Department: 2831)

Electricity: electrical systems and devices

Electrostatic capacitors

Fixed capacitor

C361S517000, C361S535000

Reexamination Certificate

active

06310756

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a capacitor for use in various kinds of electronic equipment.
BACKGROUND OF THE INVENTION
A conventional capacitor of this kind is described with reference to FIG.
17
and FIG.
18
.
As
FIG. 18
shows, a capacitor element
40
comprises a pair of electrode plates
37
a
and
38
b
, lead tabs
38
a
to
38
d
connected to the electrode plates
37
a
and
37
b
and a separator
39
. The pair of electrode plates
37
a
and
38
b
, to which the lead tabs
38
a
to
38
d
are connected, are wound with the separator
39
sandwiched therebetween.
As
FIG. 17
shows, the capacitor element
40
is contained in a bottomed cylindrical case
42
and fixed in position by a locating member
43
disposed on the inner bottom of the case
42
. A terminal plate
44
seals an opening of the case
42
using an O ring
47
. Terminals
45
for external connection are mounted on the terminal plate
44
and connected to the respective lead tabs
38
a
to
38
d
. A pressure vent
46
is provided on the terminal plate
44
. The conventional capacitor is structured as described above.
In recent years, requirements from the market have been increasing for a capacitor to have a lower resistance and a smaller size. When reducing the internal resistance with the capacitor of the foregoing structure, there are the following methods:
1. increasing the number of lead tabs like the lead tabs
38
a
to
38
d
; and
2. optimizing the connecting positions of lead tabs such as
38
a
to
38
d.
In addition to the methods of increasing the number of lead tabs, the lead out resistance, or resistance of electrical current collector, of the capacitor element
40
can be reduced as the number of lead tabs is increased as Equation 1 shows. When it comes to connecting the lead tabs, which are increased in number, to the terminal
45
for external connection, the increased number of lead tabs overlaid one over another have to be connected to a lead tab connecting member of the terminal
45
. However, there is a limit in the number of lead tabs that are allowed to be connected to the lead tab connecting member of the terminal
45
because of such problems as a limited available space in the case
42
, workability involved with lead tab connection, reliability of connection and the like, thereby prohibiting the number of lead tabs from being increased indiscriminately.
Resistance of Electrical Current Collector=1/(
3×n
2
)×(3×(L
x
/L−1/2)
2
+1/4)×L/W×&rgr;/tp1  (Equation 1)
where n: the number of lead tabs, L
x
: a distance between the end of electrode and the lead tab, L: a length of electrode, W: a width of electrode, &rgr;: specific resistance of aluminum and tp1: a thickness of electrode.
Regarding the optimizing the connecting positions of the lead tabs, when the distances between adjoining lead tabs of a plurality of lead tabs such as
38
a
to
38
d
that are connected to electrodes are made equal to one another and also the distances between the end parts of electrodes
37
a
and
37
b
and the lead tabs
38
a
and
38
c
, which are located closest to the end parts of respective electrodes
37
a
and
38
b
, are made ½ of the distances between the end parts of electrode
37
a
and
37
b
and the lead tabs
38
b
and
38
d
, respectively, the lead out resistance of the electrodes
37
a
and
37
b
of the capacitor element
40
becomes an ideal value in resistance.
However, when these electrodes are wound together, the positions of lead tabs
38
a
to
38
d
led out of the respective electrodes
37
a
and
37
b
tend to be shifted in position as the lead tabs
38
a
to
38
d
move away from the center of winding, resulting in an inadvertent problem of the lead out resistance of the electrodes
37
a
and
37
b
being increased in comparison with the foregoing ideal resistance.
With a capacitor having a structure formed by the method proposed by the same inventors of the present invention in the Japanese Patent Application No. H09-322596, when both terminals of cathode and anode electrodes are arranged to be taken out in the same direction, such problems as difficulties in reducing the height of the capacitor due to a complicated internal structure and also in producing the capacitor in large quantities have been left unsolved.
The present invention aims to address the above problems and aims at providing a capacitor that enables a reduction in internal resistance as well as in the number of components and in size.
SUMMARY OF THE INVENTION
A capacitor of the present invention comprises a hollow capacitor element formed by winding a pair of flat sheet electrodes with a separator sandwiched therebetween and with edges of respective electrodes protruding in directions opposite to each other.
The edges of the electrodes are connected with an electrode connecting material by at least one selected from a group consisting of plasma-sprayed metal, welded metal, solder and a conductive adhesive material. A terminal for external connection is connected to the electrode and a metal case containing the capacitor element together with a driving electrolyte is provided with a sealing plate to close an opening of the metal case securely.
The present invention enables the capacitor thus prepared to reduce a resistance between the pair of electrodes, to realize a reduction in size and to decrease a number of the components.


REFERENCES:
patent: 3648337 (1972-03-01), Greskamp et al.
patent: 4760494 (1988-07-01), Crum
patent: 5381301 (1995-01-01), Hudis
patent: 5847919 (1998-12-01), Shimizu et al.

Affiliated with

Also associated with

Rating

Capacitor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Capacitor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Capacitor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2599480