Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Electrode
Reexamination Certificate
2000-04-07
2002-05-14
Chaney, Carol (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Electrode
C429S185000, C429S181000, C429S178000, C429S163000
Reexamination Certificate
active
06387567
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a secondary battery, and more particularly, to a secondary battery which has an improved structure in which charging and discharging improve the battery capacity.
2. Description of the Related Art
In general, secondary batteries capable of charging and discharging are applied to portable electronic apparatus such as cellular phones, notebook-type computers, computer camcorders and the like, and research into secondary batteries is being vigorously conducted.
In particular, secondary batteries are classified into a variety of batteries, including nickel-cadmium (Ni—Cd) batteries, lead acid storage batteries, nickel metal hydride (Ni—MH) batteries, lithium ion batteries, lithium polymer batteries, metal lithium batteries, air-zinc acid storage batteries, and the like.
Among the above-mentioned batteries, lithium batteries have a service life three times longer than Ni—Cd batteries or Ni—MH batteries and are in widespread use in terms of their excellent energy density per unit weight.
Lithium batteries are classified into liquid electrolyte batteries and polymer electrolyte batteries according to the type of electrolyte used. Generally, batteries using a liquid electrolyte are called lithium ion batteries and batteries using a polymer electrolyte are called lithium polymer batteries.
Lithium secondary batteries may have various shapes. Typically, cylindrical or prismatic batteries are fabricated to be used mainly as lithium-ion batteries. Lithium polymer secondary batteries have flexibility so that they are relatively free in view of shape design. Accordingly, lithium polymer secondary batteries having excellent safety and freedom in shape design and being light-weight are advantageous in attaining miniaturized and light-weight portable electronic apparatus, and research into the lithium polymer secondary battery is being carried out in various manners.
The above-described lithium polymer secondary battery is schematically shown in FIG.
1
.
Referring to
FIG. 1
, the lithium polymer secondary battery includes an electrode assembly, a lower case
11
having a space
11
a
in which the electrode assembly is accommodated, and an upper case
12
for hermetically closing the space
11
a
of the lower case
11
. One side periphery of the upper case
12
is connected to the lower case
11
.
The electrode assembly has positive electrode plates
13
and negative electrode plates
14
stacked sequentially, with separators
15
interposed therebetween. A positive electrode tab extends from the positive electrode plate
13
at one side thereof and a negative electrode tab extends from the negative electrode plate
14
at one side thereof. A plurality of positive electrode tabs at the positive electrode plates
13
are mutually welded to form a positive electrode tab group
16
. Also, a plurality of negative electrode tabs drawn out from the negative electrode plates
14
in the same direction are mutually welded to form a negative electrode tab group
17
. A positive electrode terminal
18
and a negative electrode terminal
19
are welded to the positive and negative electrode tab groups
16
and
17
, respectively, to then be drawn outside the upper and lower case values
11
and
12
.
In the lithium polymer secondary battery having the above-described configuration, the upper and lower cases
11
and
12
which are Al multi-film pouches, are formed of various materials such as nylon, polyethylene (PE), aluminum (Al), ethyl acetic acid (EAA), polyethylene terephthalate (PET), polypropylene (PP) and the like. An electrolytic solution is injected into the upper and lower cases
11
and
12
and then the electrode assembly is installed therein. In this case, when the electrode assembly is inserted into the upper and lower cases
11
and
12
and then the upper and lower cases
11
and
12
are sealed, the electrolytic solution sticking to the portions of the positive electrode tab group
16
and the negative electrode tab group
17
stick to the sealing portions at the peripheries of the upper and lower cases
11
and
12
, which results in a sealing strength that is insufficient.
As shown in
FIG. 1
, the positive electrode terminal
18
made of Al and the negative electrode terminal
19
made of Cu or Ni which protrude outside the upper and lower cases
11
and
12
must be folded to be connected to a terminal (not shown) of a battery pack. However, in this case, the positive and negative electrode terminals
18
and
19
may contact the upper or lower case
11
or
12
in a direction in which the positive and negative electrode terminals
18
and
19
are folded, thereby undesirably causing shorts in the battery.
SUMMARY OF THE INVENTION
To solve the above problems, it is an object of the present invention to provide a secondary battery having improved safety and productivity, by preventing an electrolytic solution from sticking to the sealing portion of a case and preventing a short-circuiting from occurring due to contact between the case and terminals protruding outside the case.
Accordingly, to achieve the above object, there is provided a secondary battery including an electrode assembly formed by sequentially stacking positive electrode plates each having a positive electrode tab formed at one side thereof, negative electrode plate each having a negative electrode tab formed at one side thereof, and separators interposed between the positive electrode plates and the negative electrode plates, for insulating the positive and negative electrode plates from each other, the positive electrode tabs being welded to each other to form a positive electrode tab group, and the negative electrode tabs being welded to each other to form a negative electrode tab group, a case having a lower case part having a space in which the electrode assembly is accommodated, and an upper case part connected to one side periphery of the lower case part and fixed to the lower case part, for hermetically sealing the space of the lower case part, the upper case part and the lower case part having sealing portions at the peripheries thereof to be sealed to each other, a positive electrode terminal welded to the positive electrode tab group, the positive electrode tab group being supported in the sealing portion and protruding outward from the case, a negative electrode terminal welded to the negative electrode tab group, the negative electrode tab group being supported in the sealing portion thereof and protruding outward from the case, and short preventing means provided between the positive and negative electrode terminals and the case in a direction in which the terminals are folded.
In an embodiment of the present invention, the short preventing means,is an insulating member fixed to the positive electrode terminal and the negative electrode terminal.
In still another embodiment of the present invention, the short preventing means is an insulating member fixed to the front sidewall of the case.
Also, in another embodiment of the present invention, the short preventing means is a supporting portion formed by protruding the sealing portion outward from the case to support the positive and negative electrode terminals.
According to another aspect of the present invention, there is provided a secondary battery including an electrode assembly formed by sequentially stacking positive electrode plates each having a positive electrode tab formed at one side thereof, negative electrode plate each having a negative electrode tab formed at one side thereof, and separators interposed between the positive electrode plates and the negative electrode plates, for insulating the positive and negative electrode plates from each other, the positive electrode tabs being welded to each other to form a positive electrode tab group, and the negative electrode tabs being welded to each other to form a negative electrode tab group, a case having a lower case part having a space in which the electrode assembly is accommodated, and an upper case pa
Chaney Carol
Leydig , Voit & Mayer, Ltd.
Samsung SDI & Co., Ltd.
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