Electricity: battery or capacitor charging or discharging – Cell or battery charger structure
Reexamination Certificate
2001-11-08
2003-01-21
Tso, Edward H. (Department: 2838)
Electricity: battery or capacitor charging or discharging
Cell or battery charger structure
C320S166000
Reexamination Certificate
active
06509714
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to button or coin shaped secondary batteries and capacitors capable of being reflow soldered and, more particularly, to the structure of secondary battery or capacitor having terminals.
2. Description of the Related Art
Coin or button shaped primary and secondary batteries and capacitors which are used as auxiliary power supplies for backup for clocks and memories of portable devices are generally fitted with terminals for taking leads from the positive and negative electrodes of the batteries in use.
With respect to their terminal shapes, components have decreased in size in recent years. In a known type, terminals are inserted into a mounting board or substrate provided with holes for terminals, and the terminals are soldered from the rear side of the substrate (FIGS.
1
and
2
). Also, the surface mount type (
FIGS. 3-6
) is prevalent. In particular, a secondary battery or capacitor fitted with terminals is placed on a substrate intact. Solder-plated portions at the front ends of the terminals are placed on the front surface of the substrate. A soldering operation is performed from this front side of the substrate. The terminals of the surface mount type are so shaped that both positive and negative terminals extend a considerable distance outwardly from the outer surface of a button or coin shaped secondary battery or capacitor, for the following reason. The positive and negative terminals are hand soldered to the substrate and so the secondary battery or capacitor is protected from thermal effects.
Recently, button or coin shaped secondary batteries and capacitors have been increasingly required to be capable of being reflow soldered in order to streamline mounting operations. In the past, gaskets made of polypropylene were used. Secondary batteries and capacitors which use better heatproof gaskets made of thermoplastic engineering materials such as polyphenylene sulfide and which can be reflow soldered have been devised and put into practical use.
To surface-mount a secondary battery or capacitor, which can be reflow soldered, to a substrate, it has been necessary to bring the surfaces of the positive and negative terminals into parallel contact with the substrate surface simply if the secondary battery or capacitor having the terminals is placed on the substrate surface. with respect to the terminal shape, where the positive and negative terminals are directed in the same direction (FIGS.
7
and
8
), the center of gravity of the secondary battery or capacitor having the terminals has poor balance. This is unsuited for surface mounting. Where positive and negative terminals are directed in opposite directions (
FIGS. 3-6
; spaced apart by 180°), both positive and negative terminals easily make parallel contact with a substrate. Therefore, this type is advantageous for surface mounting and has become a mainstream.
With respect to terminal shapes of surface mount type secondary batteries and capacitors that can be reflow soldered, the shape type in which positive and negative terminals are spaced apart by 180° and directed in opposite directions is mainstream. This shape has the disadvantage that where a secondary battery or capacitor with terminals is surface-mounted to a substrate by a reflow process, the secondary battery or capacitor with terminals occupies a large area on the substrate. As components have been required to be fabricated in smaller size, it is quite important to minimize the area occupied on the substrate by the secondary battery or capacitor with terminals.
SUMMARY OF THE INVENTION
The present invention provides a structure, where either one of positive and negative terminals is placed within a square that the outer surface of a button or coin shaped secondary battery or capacitor inscribes. This greatly reduces the area taken up on the substrate by the secondary battery or capacitor fitted with the terminals.
Where the negative electrode side is placed opposite to the substrate surface, the positive electrode can and the negative terminal are brought into contact with each other by the weight of the secondary battery or capacitor after reflow solder. This creates the possibility that the positive and negative electrodes are shorted to each other. To prevent this electrical shorting, at least one step is formed on the negative terminal mounted on the negative electrode can opposite to the substrate surface. Further details of the configuration of the present invention are as follows.
(1) A secondary battery or capacitor fitted with terminals. The positive and negative terminals are mounted to the secondary battery or capacitor to take leads. Either one of these two terminals is placed substantially within a square that the outer surface of the secondary battery or capacitor inscribes.
(2) A secondary battery or capacitor fitted with terminals. The positive and negative terminals are mounted to the secondary battery or capacitor. The solder-plated portions of the positive and negative terminals are placed parallel to the substrate surface on which the secondary battery or capacitor is mounted.
(3) A secondary battery or capacitor fitted with terminals including a terminal opposite to the substrate surface on which the secondary battery or capacitor is mounted. The terminal opposite to the substrate surface has at least one step.
Generally, many of electronic components mounted on substrates are rectangular in shape. Therefore, where a round secondary battery or capacitor is mounted, dead space is created. As shown in
FIG. 15
, dead space is often created at the corners of a square
5
n
where the outer surface of a secondary battery or capacitor inscribes the square
5
n.
Therefore, a terminal
5
c
connected with an electrode located on the side of a substrate is preferably made smaller. However, the size can be increased within the range of the square
5
n.
If the terminal
5
c
is too small, the secondary battery becomes unstable. Therefore, the width
5
L is preferably set to more than 40% of the diameter R of the secondary battery. It is also necessary to set the width
5
L to less than the diameter R of the secondary battery or capacitor so that the outside diameter of the battery or capacitor does not go beyond the inscribed square
5
n.
Where stability occurring when a secondary battery is placed on a substrate is taken into consideration, the end of the terminal
5
c
should not be too close to the center of the secondary battery or capacitor. Where the distance from the end of the terminal
5
c
to the outer surface of the secondary battery or capacitor is
5
m
and the radius of the battery or capacitor is r, it is important to have 0≦
5
m
<r.
However, depending on the accuracy at which the terminal is welded, the terminal
5
c
may jut a distance equal to about 10% of the diameter of the secondary battery or capacitor out of the square
5
n.
This extent is within the scope of the present invention.
Since a terminal
5
b
connected with an electrode located on the opposite side of the substrate juts out of the inscribed square
5
n,
the size is preferably made as small as possible. The stability of the secondary battery or capacitor is secured by making the terminal
5
c
wide. This makes use of the dead space and allows more substantial high-density packaging. Consequently, the width
5
L of the terminal
5
c,
at its end, connected with the electrode on the substrate side and the width
5
k
of the terminal
5
b,
at its end, connected with the electrode located on the opposite side of the substrate preferably satisfy
5
k
<
5
L.
The terminal
5
b
connected with the electrode located on the opposite side of the substrate does not need to be positioned on a line with the terminal
5
c.
The packaging efficiency is also effectively increased by slightly tilting the terminal
5
b
such that it is located in a dead space at one corner of the inscribed square
5
n.
In this case, it is necessary to stabilize the secondary battery or capacitor
Ogata Kenji
Takiguchi Taisuke
Tomitsuka Koji
Watanabe Shunji
Adams & Wilks
SII Micro Parts Ltd.
Tso Edward H.
LandOfFree
Secondary battery with terminals and capacitor with terminals does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Secondary battery with terminals and capacitor with terminals, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Secondary battery with terminals and capacitor with terminals will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3017012