U.S. patent application number 13/090595 was filed with the patent office on 2011-08-11 for cap assembly and secondary battery using the same.
This patent application is currently assigned to SAMSUNG SDI CO., LTD.. Invention is credited to SANG-JOON LEE.
Application Number | 20110195282 13/090595 |
Document ID | / |
Family ID | 40523544 |
Filed Date | 2011-08-11 |
United States Patent
Application |
20110195282 |
Kind Code |
A1 |
LEE; SANG-JOON |
August 11, 2011 |
CAP ASSEMBLY AND SECONDARY BATTERY USING THE SAME
Abstract
A cap assembly for a secondary battery in which an insulating
member is disposed in a partial or entire terminal plate, resulting
in improved stability. The cap assembly includes a terminal plate
and an insulating member. The insulating member is disposed in a
partial or entire region of the terminal plate other than a region
to which a negative electrode tab is welded.
Inventors: |
LEE; SANG-JOON; (Suwon-si,,
KR) |
Assignee: |
SAMSUNG SDI CO., LTD.
Yongin-si
KR
|
Family ID: |
40523544 |
Appl. No.: |
13/090595 |
Filed: |
April 20, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12193420 |
Aug 18, 2008 |
7951486 |
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13090595 |
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Current U.S.
Class: |
429/7 ; 429/163;
429/181 |
Current CPC
Class: |
H01M 50/172 20210101;
H01M 50/155 20210101; H01M 50/15 20210101; Y02E 60/10 20130101;
H01M 50/543 20210101; H01M 50/147 20210101; H01M 10/0431 20130101;
H01M 10/052 20130101 |
Class at
Publication: |
429/7 ; 429/181;
429/163 |
International
Class: |
H01M 2/04 20060101
H01M002/04; H01M 2/30 20060101 H01M002/30; H01M 10/42 20060101
H01M010/42 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 5, 2007 |
KR |
10-2007-0100372 |
Claims
1. A secondary battery, comprising: an electrode assembly having
two electrode tabs including a positive electrode tab and a
negative electrode tab; an outer can accommodating the electrode
assembly; a cap plate closing the outer can; a terminal plate
including a first region in which the terminal plate rigidly
contacts one of the two electrode tabs and a second region in which
the terminal plate does not contact any one of the two electrode
tabs; and an insulating member located on the second region,
wherein the insulating member is disposed both between the cap
plate and the terminal plate and in a same plane of the first
region.
2. The secondary battery recited in claim 1, wherein the insulating
member is coated with poly-ethylene or
poly-ethylene-terephthalate.
3. The secondary battery recited in claim 1, wherein the insulating
member comprises an insulating tape attached thereon.
4. The secondary battery recited in claim 1, wherein the outer can
has a prismatic shape or an elliptical shape with rounded
edges.
5. The secondary battery recited in claim 4, wherein the outer can
is formed of aluminum, aluminum alloy, or stainless steel.
6. The secondary battery recited in claim 1, wherein the secondary
battery further comprises: a protecting circuit board disposed at
one side thereof.
7. The secondary battery recited in claim 1, wherein the secondary
battery is of an inner pack type.
8. The secondary battery recited in claim 1, wherein the secondary
battery is of a hard pack type.
9. The secondary battery recited in claim 1, wherein the first
region rigidly contacts the positive electrode tab.
10. The secondary battery recited in claim 9, wherein the negative
tab contacts the cap plate.
11. The secondary battery recited in claim 1, wherein the secondary
battery further comprises: a terminal hole disposed in the cap
plate; an insulating gasket coupled with the terminal hole and
having a central hole; an electrode terminal coupled with the
central hole; an insulating plate disposed between the cap plate
and the terminal plate; and an insulating casing located on the
electrode assembly, wherein the terminal plate electrically
connected to the electrode terminal.
Description
CLAIM OF PRIORITY
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/193,420 entitled "Cap Assembly and
Secondary Battery using the same" filed on Aug. 18, 2008, now
allowed, which claims priority to and the benefit of Korean Patent
Application No. 2007-0100372, filed on Oct. 5, 2007 in the Korean
Intellectual Property Office, the entire content of both of which
are incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a cap assembly and a
secondary battery using the same, and more particularly, to a cap
assembly and a secondary battery using the same in which an
insulating member is disposed in a partial or an entire of a
terminal plate, resulting in improved stability.
[0004] 2. Description of the Related Art
[0005] Rechargeable secondary batteries are economical in
comparison to disposable dry cells. In recent years, as low-volume
and high-capacity secondary batteries are developed, they are
widely used as power supplies for portable electronic/electrical
devices, such as cellular phones, camcorders, notebook computers
and the like.
[0006] The secondary batteries include nickel-cadmium batteries,
nickel-metal hydride batteries, nickel-zinc batteries, and lithium
secondary batteries.
[0007] Among them, the lithium secondary batteries are most widely
used because of their small size, high capacity, high operating
voltage, and high energy density per weight.
[0008] The lithium secondary batteries may be classified into
can-type lithium secondary batteries and pouch-type lithium
secondary batteries depending on shapes of a casing, which
accommodates an electrode assembly having a negative electrode
plate, a positive electrode plate and a separator. The can-type
lithium secondary batteries may be further classified into
cylinder-type lithium secondary batteries and prismatic-type
lithium secondary batteries.
[0009] When the lithium secondary battery is of the can type, the
casing is generally formed of a metal such as aluminum and has a
cylindrical shape, a prismatic shape, or a pillar shape with
rounded edges.
[0010] The can has an upper opening through which an electrode
assembly is inserted and electrolyte is injected into the can.
[0011] The can is then finished by a cap assembly having a size and
shape corresponding to the opening of the can, resulting in a
sealed bare cell.
[0012] When the lithium secondary battery is of the pouch-type, a
pouch casing has a space for accommodating an electrode assembly,
which is accommodated on a lower surface of the casing.
[0013] The lower surface is covered with an upper surface of the
pouch casing, and sealing portions are formed at edges of the upper
and lower surfaces of the pouch casing and bonded in order to be
sealed, resulting in a bare cell.
[0014] The bare cell configured above is electrically connected
with a protecting circuit board, which includes a protecting device
for preventing accident caused by abnormal operation, such as
overcharge, overdischarge, overcurrent, and the like.
[0015] In general, the electrical connection between the bare cell
and the protecting circuit board is made via a lead. Such a
secondary battery may be called a core pack.
[0016] The core pack is received in a separate casing or a gap of
the core pack is filled with a hot-melt resin. The core pack is
then subjected to a tubing process with a thin casing and a
labeling process, resulting in a battery pack.
[0017] In a prismatic-type secondary battery, the conductive
terminal plate forming the cap assembly may stab into the electrode
assembly or may be brought into contact and short-circuited with
the can when the cap assembly finishing the opening of the can is
partially distorted and bent toward the electrode assembly by
external pressure, causing a stability issue such as a fire and an
explosion.
[0018] The above information disclosed in this Related Art section
is only for enhancement of understanding of the background of the
invention and therefore it may contain information that does not
form the prior art that is already known to a person of ordinary
skill in the art.
SUMMARY OF THE INVENTION
[0019] In accordance with an exemplary embodiment, the present
invention provides a cap assembly comprising a terminal plate and
an insulating member, wherein the insulating member disposed in a
partial or an entire region of the terminal plate other than a
region to which a positive electrode tab is welded.
[0020] In accordance with another exemplary embodiment, the present
invention provides a secondary battery comprising: an electrode
assembly including a negative electrode tab and a positive
electrode tab; a can for accommodating the electrode assembly, the
can including an upper opening; and a cap assembly for finishing
the upper opening, in which the cap assembly comprises a terminal
plate and an insulating member, wherein the insulating member
disposed in a partial or an entire region of the terminal plate
other than a region to which the negative electrode tab is
welded.
[0021] The insulating member may be coated with poly-ethylene or
poly-ethylene-terephthalate.
[0022] The insulating member may comprise an insulating tape
attached thereon.
[0023] The secondary battery is of an inner pack type or a hard
pack type.
[0024] According to the present invention, it is possible to
prevent the conductive terminal plate forming the cap assembly from
stabbing into the electrode assembly or from being brought into
contact and abnormally short-circuited with the can when the cap
assembly finishing the opening of the can is partially distorted
and bent toward the electrode assembly by external pressure.
[0025] Thus, a fire and an explosion caused by the abnormal
short-circuit can be also prevented, thereby improving stability of
the battery.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] A more complete appreciation of the invention, and many of
the attendant advantages thereof, will be readily apparent as the
same becomes better understood by reference to the following
detailed description when considered in conjunction with the
accompanying drawings in which like reference symbols indicate the
same or similar components, wherein:
[0027] FIG. 1 is an exploded perspective view of a secondary
battery according to an embodiment of the present invention;
and
[0028] FIG. 2 is an assembled cross-sectional view illustrating the
secondary battery of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Hereinafter, preferred embodiments of the present invention
will be described in detail with reference to the accompanying
drawings. Thicknesses, distances and the like of layers and areas
in the drawings may be exaggerated for convenience of
illustration.
[0030] FIGS. 1 and 2 are an exploded perspective view and an
assembled cross-sectional view illustrating a secondary battery
according to an embodiment of the present invention.
[0031] Referring to FIGS. 1 and 2, the secondary battery includes
an electrode assembly 10, a can 20 for accommodating the electrode
assembly 10, and a cap assembly 30 disposed on an opening of the
can 20.
[0032] The electrode assembly 10 includes a positive electrode
plate 11 having a positive electrode collector coated with a
positive electrode active material, a negative electrode plate 13
having a negative electrode collector coated with a negative
electrode active material, and a separator 15 interposed between
the positive electrode plate 11 and the negative electrode plate 13
for preventing a short-circuit between the plates 11 and 13 and
allowing for movement of lithium ions.
[0033] The positive electrode plate 11 includes a non-coating
portion that is not coated with the positive electrode active
material, and the negative electrode plate 13 includes a
non-coating portion that is not coated with the negative electrode
active material.
[0034] A positive electrode tab 17 is bonded to the positive
electrode non-coating portion and electrically connected to a cap
plate, and a negative electrode tab 19 is bonded to the negative
electrode non-coating portion and electrically connected to an
electrode terminal.
[0035] In this case, the positive electrode tab 17 and the negative
electrode tab 19 may be respectively bonded to the positive
electrode non-coating portion and the negative electrode
non-coating portion by ultrasonic welding. The present invention is
not limited to the ultrasonic welding.
[0036] The positive electrode collector may be formed of stainless
steel, nickel, aluminum, titanium, an alloy thereof, aluminum, or
stainless steel that is surface-treated with carbon, nickel,
titanium, or silver. Preferably, the positive electrode collector
is formed of aluminum or aluminum alloy.
[0037] The positive electrode collector may be formed as a foil, a
film, a sheet, a punched material, a porous material, a foam, and
the like. The positive electrode collector has a thickness of 1 to
50 .mu.m and preferably 1 to 30 .mu.m. Here, the positive electrode
collector is not limited to such shapes and thicknesses.
[0038] The positive electrode active material is capable of
inserting or extracting lithium ions. Preferably, the positive
electrode active material is at least one selected from a group
consisting of cobalt, manganese, and nickel and at least one
lithium composite oxide.
[0039] The negative electrode collector may be formed of stainless
steel, nickel, copper, titanium, an alloy thereof, copper, or
stainless steel that is surface-treated with carbon, nickel,
titanium, or silver. Preferably, the negative electrode collector
is formed of copper or a copper alloy.
[0040] The negative electrode collector may be formed as a foil, a
film, a sheet, a punched material, a porous material, a foam, and
the like. The negative electrode collector has a thickness of 1 to
50 .mu.m, preferably 1 to 30 .mu.m. Here, the negative electrode
collector is not limited to such shapes and thicknesses.
[0041] The negative electrode active material is capable of
inserting or extracting lithium ion, and may include a carbon
material, such as crystalline carbon, amorphous carbon, carbon
composite, and carbon fiber, a lithium metal, a lithium alloy,
etc.
[0042] The separator 15 is typically formed of a thermoplastic
resin, such as poly-ethylene (PE) and polypropylene (PP) and has a
surface in a porous film structure.
[0043] This porous film structure becomes an insulating film as the
separator 15 is melted and the holes are clogged when an internal
temperature of the battery is elevated to a melting point of the
thermoplastic resin.
[0044] The insulating film blocks lithium ion between the positive
electrode plate 11 and the negative electrode plate 13 and,
accordingly, current no longer flows, thereby stopping elevation of
the internal temperature of the battery.
[0045] The can 20 may be formed of a metal material and have an
upper opening. The can 20 may accommodate the electrode assembly 10
and the electrolyte, and have an insulating casing disposed on the
electrode assembly.
[0046] The metal material may be light and flexible aluminum,
aluminum alloy or stainless steel. When the can 20 is formed of the
metal material, it may have a polarity and be used as an electrode
terminal.
[0047] The can 20 may have a prismatic shape or an elliptical shape
with rounded edges. The upper opening of the can 20 is welded or
melt-bonded to the cap plate to be sealed.
[0048] The cap assembly 30 is coupled with the upper opening of the
can 20 and includes an insulating casing 31, a cap plate 32, an
insulating gasket 33, an electrode terminal 34, an insulating plate
35, a terminal plate 36, and a plug 37 for an electrolyte injection
hole.
[0049] The insulating casing 31 is located on the electrode
assembly 10 inserted into the can 20 for preventing movement of the
electrode assembly 10.
[0050] The insulating casing 31 has sidewalls so that the terminal
plate 36 and the insulating plate 35 covering the terminal plate 36
are set in the insulating casing 31.
[0051] The insulating casing 31 also isolates between the positive
electrode tab 17 and the negative electrode tab 19 by a
predetermined distance so that they are not short-circuited. The
insulating casing 31 may include an external groove serving as a
guide.
[0052] The insulating casing 31 may be formed of an insulating
polymer resin, such as polypropylene (PP), polyphenylene sulfide
(PPS), polyethersulfone (PES), or degenerated poly phenylene oxide
(PPO).
[0053] The cap plate 32 is coupled with the upper opening of the
can 20 to seal the opening. The cap plate 32 is a metal plate
having the same size and shape as the opening, and includes a
terminal hole 32a into which the insulating gasket 33 and the
electrode terminal 34 may be inserted.
[0054] The cap plate 32 further includes an electrolyte injection
hole 32b that provides a passage for injecting the electrolyte into
the can 10.
[0055] After the electrolyte is injected, the can 20 is sealed by
sealing the electrolyte injection hole 32b with the plug 37.
[0056] The insulating gasket 33 is coupled with the terminal hole
32a of the cap plate 32. The insulating gasket 33 is formed of a
rubber or another nonconductive material having good conductivity
to insulate between the electrode terminal 34 and the cap plate
32.
[0057] The insulating gasket 33 has a central hole for coupling
with the electrode terminal 34. When the insulating gasket 33 is
coupled with the electrode terminal 34, it surrounds an outer side
of the electrode terminal 34.
[0058] The electrode terminal 34 is coupled with the cap plate 32
in such a manner that it is inserted into the hole of the
insulating gasket 33. A lower end of the electrode terminal 34
passing through the cap plate 32 is electrically connected to the
terminal plate 36.
[0059] The insulating plate 35 is formed of an insulating material
and located on a lower surface of the cap plate 32 for insulating
the cap plate 32 and the terminal plate 36, which is located on the
lower surface of the insulating plate 35.
[0060] The insulating plate 35 includes a hole corresponding to the
terminal hole 32a of the cap plate 32.
[0061] The electrode terminal 34 is inserted through the hole and
connected with the terminal plate 36 and electrically connected to
the negative electrode tab 19 of the electrode assembly 10 welded
to the terminal plate 36.
[0062] The terminal plate 36 is located on the lower surface of the
insulating plate 35. The terminal plate 36 is formed of a
conductive material and establishes an electrical path between the
negative electrode tab 19 of the electrode assembly 10, which is
welded to the lower surface of the terminal plate 36, and the
electrode terminal 34.
[0063] The cap assembly 30 may further include an insulating member
36a disposed in a partial or an entire region of the terminal plate
36 other than the region to which the negative electrode tab 19 is
welded. As illustrated in FIG. 2, the insulating member 36a may
include a part locating on a surface to which the negative
electrode tab 19 is welded. The insulating member 36a may be
disposed in an edge of the lower surface of the terminal plate 36.
The insulating member 36a may surround or encase an edge of the
terminal plate 36.
[0064] The insulating member 36a may be coated with a nonconductive
material that is not corroded by the electrolyte, such as
poly-ethylene (PE) or poly-ethylene-terephthalate (PET), or may
include an insulating tape attached thereon.
[0065] The insulating member 36a can prevent the conductive
terminal plate forming the cap assembly from stabbing into the
electrode assembly or from being brought into contact and
short-circuited with the can when the cap assembly finishing the
opening of the can is partially distorted and bent toward the
electrode assembly by external pressure.
[0066] For the secondary battery as the bare cell configured above,
a core pack with a protecting circuit board disposed at one side
thereof may be subjected to a tubing process with a thin casing and
a labeling process, resulting in an inner pack
[0067] Alternatively, the core pack with the protecting circuit
board disposed at one side thereof may be received in a separate
casing, resulting in a hard pack.
[0068] The invention has been described using preferred exemplary
embodiments. However, it is to be understood that the scope of the
invention is not limited to the disclosed embodiments. On the
contrary, the scope of the invention is intended to include various
modifications and alternative arrangements within the capabilities
of persons skilled in the art using presently known or future
technologies and equivalents. The scope of the claims, therefore,
should be accorded the broadest interpretation so as to encompass
all such modifications and similar arrangements.
* * * * *