Field on the invention
[0001] Aspects of embodiments of the present invention relate to a rechargeable
battery.
BACKGROUND
2. Description of the Related Art
[0002] A rechargeable battery differs from a primary battery in that it can be
repeatedly charged and discharged, while the latter is incapable of being recharged.
[0003] A low-capacity rechargeable battery is used in small portable electronic
devices such as mobile phones, notebook computers, and camcorders, while a
high-capacity rechargeable battery can be widely used as a power source for driving a
motor of hybrid vehicles and the like.
[0004] Recently, a high power rechargeable battery using a non-aqueous electrolyte
and hav'mg high energy density has been developed, and the high power rechargeable
battery consists of a large-capacity rechargeable battery in which a plurality of
rechargeable batteries are connected in series, such that it can be used as a power
source for driving a motor of a device requiring a large amount of electric power, for
example, an electric vehicle or the like.
[0005] In addition, a high-capacity rechargeable battery generally includes a plurality
of rechargeable batteries connected in series, and the rechargeable battery may have a
cylindrical shape, a prismatic shape, etc.
[0006] When internal pressure of the rechargeable battery, of which a case is made
of a metal, etc., is increased by an abnormal reaction, the case should be opened and
charging and discharging operations needs to be disabled.
[0007] In order to disable the charging and discharging operations, a short-circuit
should be induced to discharge a charged current.
[0008] The above information disclosed in this Background 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 in this country to
a person of ordinary skill in the art.
SUMMARY
[0009] According to an aspect of embodiments of the present invention, a
rechargeable battery is capable of inducing and maintaining a short circuit state when a
danger occurs and thus stably discharging a charged current. According to an aspect of
embodiments of the present invention, a rechargeable battery has a short-circuit
protrusion.
[0010] According to one or more exemplary embodiments of the present invention, a
rechargeable battery includes: an electrode assembly including a first electrode and a
second electrode; a case for accommodating the electrode assembly; a first terminal
electricaliy coupled to the first electrode and a second terminal electrically coupled to the
second electrode; a cap plate combined to the case and formed with a short-circuit hole;
a membrane fixed to the cap plate and electricaliy separating or short-circuiting the first
electrode and the second electrode; and a short-circuit protrusion electrically coupled to
the second electrode and disposed above the membrane to protrude theretoward. The
short-circuit protrusion is disposed to be shifted toward one side from a center of the
short-circuit hole.
[0011] The membrane may be disposed to be inserted into the short-circuit hole, the
short-circuit protrusion may be disposed above the short-circuit hole, and the
3
short-circuit protrusion may be disposed to be shifted from a center of the short-circuit
hole and to be adjacent to a connection terminal that is inserted into the second terminal.
[0012] The short-circuit protrusion may be disposed between the center of the
short-circuit hofe and a connection terminal that is inserted into the second terminal, and
the short-circuit protrusion may be formed to be elongated in an arc shape.
[0013] A cross-section of the short-circuit protrusion may be formed in a semi-circuiar
shape, and a groove having an arc-shaped cross-section may be formed at a bottom
surface of the short-circuit protrusion.
[0014] The short-circuit protrusion may be formed to protrude from a bottom surface
of the second terminal, a connection plate may be disposed under the second terminal,
and the short-circuit protrusion may be formed to protrude from the connection plate.
[0015] An inclined portion may be slantedly formed at a lower end of the short-circuit
protrusion with respect to the connection plate, a cylindrical portion protruding toward the
membrane and having a tubal shape may be formed in the connection plate, and the
short-circuit protrusion may be formed to protrude from a lower end of the cylindrical
portion.
[0016] A cap may be installed to be inserted into the cylindrical portion, an upper
insulating member may be disposed between the connection plate and the cap plate,
and the upper insulating member may be installed to enclose the connection piate.
[0017] According to an aspect of embodiments of the present invention, resistance
between the membrane and the short-circuit protrusion is decreased to maintain the
short circuit state, thereby stably discharging a charged current.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a perspective view of a rechargeable battery according to an
exemplary embodiment of the present invention.
[0019] FIG. 2 is a cross-sectional view of the rechargeable battery of FIG. 1, taken
along the line ll-ll.
[0020] FIG. 3 is a perspective view of a second terminal according to a first
exemplary embodiment of the present invention viewed from the bottom.
[0021] FIG. 4 is a partial cross-sectional view of the rechargeable battery according
to the first exemplary embodiment of the present invention.
[0022] FIG. 5 is a vertical cross-sectional view of a rechargeable battery according to
a second exemplary embodiment of the present invention.
[0023] FIG. 6 is a perspective view of a connection plate according to the second
exemplary embodiment of the present invention viewed from the bottom.
[0024] FIG. 7 is a vertical cross-sectional view of the connection plate according to
the second exemplary embodiment of the present invention.
[0025] FIG. 8 is a perspective view of a connection plate according to a third
exemplary embodiment of the present invention viewed from the bottom.
[0026] FIG. 9 is a vertical cross-sectional view of the connection plate according to a
third exemplary embodiment of the present invention.
[0027] FIG. 10 is a vertical cross-sectional view of a rechargeable battery according
to a fourth exemplary embodiment of the present invention.
[0028] FIG. 11 is a perspective view of a connection plate according to the fourth
exemplary embodiment of the present invention viewed from the bottom.
Description of Reference Numerals Indicating Some Elements in the Drawings
[0029]
10|: rechargeable battery 10: electrode assembly
11: first electrode • 11a: first electrode uncoated region
12: second electrode 12a: second electrode uncoated region
5
13: separator
22, 62, 72: second terminal
22b, 64b, 67b, 84: short-circuit protrusion
26: connection terminal
30: cap assembly
37: short-circuit hole
42: second current collecting member
54, 65, 74: upper insulating member
56: membrane
63: cover plate
64c: inclined portion
81: plate portion
83: bottom
21, 71: first terminal
22a, 64a, 67a, 86: terminal hole
25, 26, 73, 75: connection terminal
27:case
31: cap plate
41: first current collecting member
43, 45: lower insulating member
55, 59: sealing gasket
58: connection member
64, 67, 80: connection plate
78: cap
82: cylindrical portion
85: through-hole
DETAILED DESCRIPTION
[0030] The present invention will be described more fully hereinafter with reference to
the accompanying drawings, in which some exemplary embodiments of the invention
are shown.
[0031] As those skilled in the art would realize, the described embodiments may be
modified in various different ways, all without departing from the spirit or scope of the
present invention. Accordingly, the drawings and description are to be regarded as
illustrative in nature and not restrictive.
[0032] Like referehce numerals designate like elements throughout the specification
and the drawings.
6
[0033] FIG. 1 is a perspective view of a rechargeable battery according to an
exemplary embodiment of the present invention; and FIG. 2 is a cross-sectional view of
the rechargeable battery of FIG. 1, taken along the line ll-ll.
[0034] Referring to FIGS. 1 and 2, a rechargeable battery 101 according to an
exemplary embodiment of the present invention includes an electrode assembly 10
formed by winding a first electrode (e.g., a positive electrode) 11 and a second electrode
(e.g., a negative electrode) 12 while interposing a separator 13 therebetween, a case 27
for accommodating the electrode assembly 10, and a cap assembly 30 combined to an
opening of the case 27.
[0035] The rechargeable battery 101 according to one embodiment is illustrated as a
prism-shaped lithium ion rechargeable battery. However, the present invention is not
limited thereto, and the present invention may be applied to various types of batteries
such as a lithium polymer battery, a cylindrical battery, etc.
[0036] The positive electrode 11 and the negative electrode 12 include coated
regions where an active material is coated on a current collector formed of a thin metal
foil, and uncoated regions 11a and 12a where the active material is not coated thereon.
[0037] The positive electrode uncoated region 11 a is formed at one lateral end of the
positive electrode 11 along a length direction thereof, and the negative electrode
uncoated region 12a is formed at the other lateral end of the negative electrode 12 along
a length direction thereof.
[0038] The positive electrode 11 and the negative electrode 12 are wound while
interposing the separator 13 as an insulator therebetween.
[0039] However, the present invention is not limited thereto, and the electrode
assembly 10 may be formed in a layered structure in which the negative electrode 12
and the positive electrode 11, respectively formed of a plurality of sheets, are layered
while interposing the separator 13 between them.
7
[0040] The case 27 is substantially formed as a cuboid, and one side thereof is
formed with an opening.
[0041] The case 27 may be formed of a metal such as aluminum, stainless steel, etc.
[0042] The cap assembly 30 includes a cap plate 31 that covers the opening of the
case 27, a first terminal 21 that protrudes out of the cap plate 31 to be electncally
coupled to the positive electrode 11, and a second terminal 22 that protrudes out of the
cap plate 31 to be electrically coupled to the negative electrode 12.
[0043] The cap plate 31 is formed as an elongated plate in one direction such that it is
combined to the opening of the case 27.
[0044] The cap plate 31 is provided with a sealing cap 38 that is inserted in an
electrolyte injection opening 32, and a vent plate 39 that is provided in a vent hole 34 to
be opened at a predetermined pressure and that is formed with a notch 39a.
[0045] The first and second terminals 21 and 22 are installed to protrude above the
cap plate 31.
[0046] The first terminal 21 is electrically coupled to the positive electrode 11 through
a first current collecting member 41, and the second terminai 22 is electrically coupled to
the negative electrode 12 through a second current collecting member 42.
[0047] However, the present invention is not limited thereto, and the first terminal 21
may be electrically coupled to the negative electrode, while the second terminal 22 may
be electrically coupled to the positive electrode.
[0048] The first terminal 21 has a rectangular plate shape. The first terminal 21 is
electrically coupled to the positive electrode 11 through a connecting terminal 25 that is
bonded to the first current collecting member 41.
[0049] The connecting terminals 25 combined to the first terminal 21 and a
connecting terminal 26 combined to the second terminal 22 have the same structure.
[0050] A sealing gasket 59 for sealing is installed between the first terminal 21 and
the cap plate 31 to be inserted Into a hole through which the terminal penetrates, and a
lower insulating member 43 is provided under the cap plate 31 to support the first current
collecting member 41.
[0051] A connection member 58 is installed under the first terminal 21 to electrically
connect the first terminal 21 with the cap plate 31.
[0052] Accordingly, the cap plate 31 and the case 26 are positively charged.
[0053] The second terminal 22 has a cuboid shape.
[0054] The second terminal 22 is electrically coupled to the negative electrode 12
through the connecting terminal 26 that is bonded to the second current collecting
member 42.
[0055] The connecting terminal 26 penetrates the cap plate 31 and the second
terminal 22 such that its upper portion is fixed to the second terminal 22,
[0056] A sealing gasket 55 for sealing is provided between the second terminal 22
and the cap plate 31 to be inserted into a hole through which the terminal penetrates,
and a lower insulating member 45 is provided under the cap plate 31 to insulate the
second terminal 22 from the second current collecting member 42.
[0057] The second terminal 22 is formed to be elongated in one direction so as to
cover the short-circuit hole 37.
[0058] An upper insulating member 54 is installed between the second terminal 22
and the cap plate 31 to electrically insulate the second terminal 22 from the cap plate 31.
[0059] Since the cap assembly 30 includes a membrane 56 for short-circuiting the
positive electrode 11 with the negative electrode 12, the membrane 56 is electrically
coupled to the cap plate 31 and is deformed to be coupled to the second terminal 22
when internal pressure of the rechargeable battery 101 increases.
[0060] The short-circuit hole 37 is formed in the cap plate 31, and the membrane 56 is
disposed between the upper insulating member 54 and the cap plate 31 at the
short-circuit hole 37.
[0061] The membrane 56 includes a curved portion that is downwardly convex in an
arc shape, and an edge portion that is formed at end portions of the curved portion to be
fixed to the cap plate 31.
[0062] When a gas is generated due to an abnormal reaction in the rechargeable
battery 101, the internal pressure of the'rechargeable battery 101 increases.
[0063] When the internal pressure of the rechargeable battery 101 exceeds a
predetermined pressure, the curved portion is deformed to be upwardly convex, and in
this case, the short-circuit protrusion and the membrane 56 contact each other to cause
a short-circuit.
[0064] As shown in FIGS. 3 and 4, the second terminal 22 is formed with a terminal
hole 22a into which the connection terminal 26 is inserted, and a short-circuit protrusion
22b protruding toward the short-circuit hole 37.
[0065] The connection terminal 26 is fixed by riveting to an upper end of the terminal
hole 22a.
[0066] In addition, a groove 22c into which a catching protrusion formed in the upper
insulating member 54 is inserted is formed at opposite lateraf sides of the second
terminal 22.
[0067] The short-circuit protrusion 22b protrudes toward the membrane 56 from a
bottom surface of the second terminal 22 and is formed to be elongated in an arc shape.
[0068] A cross-section of the short-circuit protrusion 22b may have a substantially
semi-circular shape.
10
[0069] The short-circuit protrusion 22b is disposed to be shifted toward one side from
a center X1 of the short-circuit hole 37 such that it is adjacent to the connection terminal
26.
[0070] The short-circuit protrusion 22b is disposed between the center of the
short-circuit hole 37 and the connection terminal 26.
[0071] When the short-circuit protrusion 22b is disposed to be shifted as such, the
short-circuit protrusion 22b and the membrane 56 contact each other at a position where
the short-circuit protrusion 22b and the membrane 56 are adjacent to the connection
terminal 26 when the membrane 56 is inversely deformed.
[0072] The short-circuit current flows to the connection terminal 26 from the
membrane 56 byway of the short-circuit protrusion 22b and the second terminal 22, and
a current path increases in its length and thus a relatively great amount of heat is
generated when the short-circuit protrusion is disposed further away from the connection
terminal 26.
[0073] Since a large amount of current flows in a short period of time when the
short-circuit occurs, even a small difference in resistance may cause a large difference in
the generated heat.
[0074] When much heat is generated, the short-circuit protrusion 22b or membrane
56 is melted to halt a short-circuit state such that an unstable state is maintained.
[0075] Thus, it is very crucial to maintain the short-circuit state by decreasing the
generated heat.
[0076] As in the current first exemplary embodiment, when the short-circuit protrusion
22b is disposed to be shifted toward the connection terminal 26, the path of the
short-circuit current decreases in length and thus the generated heat is reduced, thereby
maintaining the short-circuit state.
11
[0077] FIG. 5 is a vertical cross-sectional view of a rechargeable battery according to
a second exemplary embodiment of the present invention.
[0078] Referring to FIG. 5, since the rechargeable battery 102 according to the
current second exemplary embodiment has the same structure as the rechargeable
battery according to the aforementioned first exemplary embodiment, except for a
second terminal 62 and a connection plate 64, a repeated description of the same
structure will be omitted.
[0079] The second terminal 62 has a cuboid shape.
[0080] The second terminal 62 is electrically coupled to the negative electrode 12
through the connection terminal 26 that is bonded to the second current collecting
member 42.
[0081] The connection terminal 26 penetrates the cap plate 31 and the second
terminal 22 such that its upper end is fixed to the second terminal 62.
[0082] The connection plate 64 is disposed under the second terminal 62, and the
connection plate 64 is disposed to be elongated from under the second terminal 62 to
above the short-circuit hole 37.
[0083] A cover plate 63 is installed above the connection plate 64 such that its lateral
end contacts the second terminal 62, and an upper insulating member 65 is installed
between the connection plate 64 and the cap plate 31 to insulate the connection plate 64
from the cap plate 31.
[0084] FIG. 6 is a perspective view of a connection plate according to the second
exemplary embodiment of the present invention viewed from the bottom, and FIG. 7 is a
vertical cross-sectional view of the connection plate according to the second exemplary
embodiment of the present invention.
[0085] Referring to FIGS. 6 and 7, the connection plate 64 is electrically coupled to
the second terminal 62 to be negatively charged.
12
[0086] A terminal hole 64a into which the connection terminal 26 is inserted is formed
in the connection plate 64, and a short-circuit protrusion 64b protruding toward the
membrane 56 is formed at a bottom surface of the connection plate 64.
[0087] The short-circuit protrusion 64b is disposed to be shifted toward one side from
the center of the short-circuit hole 37 such that it is adjacent to the connection terminaf
26.
[0088] The short-circuit protrusion 64b is disposed between the center of the
short-circuit hole 37 and the connection terminal 26.
[0089] The short-circuit protrusion 64b protrudes toward the membrane 56 from the
bottom surface of the connection plate 64 and is formed to be elongated in an arc shape.
[0090] A cross-section of the short-circuit protrusion 64b may have a substantially
semi-circular shape.
[0091] Meanwhile, an inclined portion 64c is slantedly formed at a bottom surface of
the short-circuit protrusion 64b with respect to the connection plate.
[0092] FIG. 8 is a perspective view of a connection plate according to a third
exemplary embodiment of the present invention viewed from the bottom, and FIG. 9 is a
vertical cross-sectionai view of the connection plate according to a third exemplary
embodiment of the present invention.
[0093] Referring to FIGS. 8 and 9, the rechargeable battery according to the current
third exemplary embodiment has the same structure as the rechargeable battery
according to the aforementioned second exemplary embodiment, except for a
connection plate 67, so a repeated description of the same structure will be omitted.
[0094] The connection plate 67 is disposed under the second terminal 62, and is
electrically coupled to the second terminal 62 to be negatively charged.
[0095] A terminal hole 67a into which the connection terminal 26 is inserted is formed
in the connection plate 67, and a short-circuit protrusion 67b protruding toward the
membrane 56 is formed at a bottom surface of the connection plate 67.
[0096] The short-circuit protrusion 67b is disposed to be shifted toward one side from
the center of the short-circuit hole 37 such that it is adjacent to the connection terminal
26.
[0097] The short-circuit protrusion 67b is disposed between the center of the
short-circuit hole 37 and the connection terminal 26.
[0098] The short-circuit protrusion 67b protrudes toward the membrane 56 from the
bottom surface of the connection plate 67, and a cross-section of the short-circuit
protrusion 67b may have a substantially semi-circular shape.
[0099] In addition, a groove 67c is slantedly formed at the bottom surface of the
short-circuit protrusion 67b.
[00100] As such, when the groove 67c having an arc-shaped cross-section is formed
at the bottom surface of the short-circuit protrusion 67b, a contact area between the
membrane 56 and the short-circuit protrusion 67b increases and thus resistance
therebetween can be decreased.
[00101] FIG. 10 is a vertical cross-sectional view of a rechargeable battery according
to a fourth exemplary embodiment of the present invention, and FIG. 11 is a perspective
view of a connection plate according to the fourth exemplary embodiment of the present
invention viewed from the bottom.
[00102] Referring to FIGS. 10 and 11, the rechargeable battery 103 according to the
current fourth exemplary embodiment has a structure that is identical or similar to that of
the rechargeable battery according to the aforementioned third exemplary embodiment,
except for-a connection plate 80 and a cap 78, so a repeated description of the same
structure will be omitted.
14
[00103] A first terminal 71 has a cuboid shape and is electrically coupled to the first
current collecting member 41 through a connection terminal 73 having a pillar shape.
[00104] The connection member 58 is installed under the first terminal 71 to
electrically connect the first terminal 71 with the cap plate 31.
[00105] The second terminal 62 has a cuboid shape and is electrically coupled to the
negative electrode 12 through a connection terminal 75 that is bonded to the second
current collecting member 42.
[00106] The connection terminal 75 penetrates the cap plate 31 and a second terminal
72 such that its upper end is fixed to the second terminal 72.
[00107] The connection plate 80 is disposed under the second terminal 72, and the
connection plate 80 is disposed to be elongated from under the second terminal 72 to
above the short-circuit hole 37.
[00108] The connection plate is disposed above the membrane 56 to be separated
therefrom, and an upper insulating member 74 is installed between the connection plate
80 and the cap plate 31 to insulate the connection plate 80 from the cap plate 31.
[00109] The connection plate 80 includes a plate portion 81 that contacts a bottom
surface ofthe second terminal 72 to be coupled thereto, and a cylindrical portion 82 that
protrudes toward the membrane 56 from the piate portion 81.
[00110] In addition, a terminal hole 86 into which the connection terminal 75 is inserted
is formed in the connection plate 80.
[00111] A bottom 83 traversing the cylindrical portion 82 is formed at a bottom ofthe
cylindrical portion 82, and a through-hole 85 is formed at the bottom 83.
[00112] A cap 78 is inserted on top ofthe cylindrical portion 82, and the cap 78 not only
prevents water from being introduced into the cylindrical portion 82 but also allows air to
be discharged outside from inside ofthe cylindrical portion 82.
[00113] A short-circuit protrusion 84 protruding downwardly toward the membrane 56
is formed at a lower end of the cylindrical portion 82, and the short-circuit protrusion 84
downwardly protrudes from an external circumferential surface of the cylindrical portion
82.
[00114] The short-circuit protrusion 84 is disposed to be shifted toward one side from
the center of the short-circuit hole 37 such that it is adjacent to the connection terminal
75.
[00115] The short-circuit protrusion 84 is disposed between the center of short-circuit
hole 37 and the connection terminal 75.
[00116] The short-circuit protrusion 84 protrudes toward the membrane 56 from a
bottom surface of the connection plate 64, and is formed to be elongated in an arc
shape.
[00117] A cross-section of the short-circuit protrusion 84 may have a substantially
semi-circular shape.
[00118] While the present invention has been described in connection with some
exemplary embodiments, it is to be understood that the present invention is not limited to
the disclosed embodiments, but, on the contrary, is intended to cover various
modifications and equivalent arrangements included within the spirit and scope of the
appended claims.

WE CLAIM:
1. A rechargeable battery comprising:
an electrode assembly including a first electrode and a second electrode;
a case for accommodating the electrode assembly;
a first terminal electrically coupled to the first electrode and a second terminal
electrically coupled to the second electrode;
a cap plate combined to the case and formed with a short-circuit hole;
a membrane fixed to the cap plate and electrically separating or short-circuiting
the first electrode and the second electrode; and
a short-circuit protrusion electrically coupled to the second electrode and
disposed above the membrane to protrude theretoward, wherein the short-circuit
protrusion is disposed to be shifted toward one side from a center of the short-circuit
hole.
2. The rechargeable battery as claimed in claim 1, wherein the membrane is
disposed to be inserted into the short-circuit hole, and the short-circuit protrusion is
disposed above the short-circuit hole.
3. The rechargeable battery as claimed in claim 2, wherein the short-circuit
protrusion is disposed to be shifted from a center of the short-circuit hole and to be
adjacent to a connection terminal that is inserted into the second terminal.
4. The rechargeable battery as claimed in claim 2, wherein the short-circuit
protrusion is disposed between the center of the short-circuit hole and a connection
terminal that is inserted into the second terminal.
17
5. The rechargeable battery as claimed in claim 3, wherein the short-circuit
protrusion is formed to be elongated in an arc shape.
6. The rechargeable battery as claimed in claim 3, wherein a cross-section of
the short-circuit protrusion is formed in a semi-circular shape.
7. The rechargeable battery as claimed in claim 6, wherein a groove having
an arc-shaped cross-section is formed at a bottom surface of the short-circuit protrusion.
8. The rechargeable battery as claimed in claim 4, wherein the short-circuit
protrusion is formed to protrude from a bottom surface of the second terminal.
9. The rechargeable battery as claimed in claim 4, wherein a connection plate
is disposed under the second terminal, and the short-circuit protrusion is formed to
protrude from the connection plate.
10. The rechargeable battery as claimed in claim 4, wherein an inclined portion
is slantedly formed at a lower end of the short-circuit protrusion with respect to the
connection plate.
11. The rechargeable battery as claimed in claim 9, wherein a cylindrical
portion protruding toward the membrane and having a tubal shape is formed in the
connection plate, and the short-circuit protrusion is formed to protrude from a lower end
of the cylindrical portion.
12. The rechargeable battery as claimed in ^laim 11, wherein a cap is installed
to be inserted into the cylindrical portion.
13. The rechargeable battery as claimed in c|ajm 11, wherein an upper
insulating member is disposed between the connection plate and the cap plate, and the
upper insulating member is installed to enclose the connection plate.