RECHARGEABLE BATTERY HAVING A CURRENT DISTRIBUTION
MEMBER
BACKGROUND
1. Field
[0001] Embodiments relate to a rechargeable battery having a current distribution
member.
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 may be used in small portable electronic
devices, e.g., mobile phones, notebook computers, and camcorders, and a high-capacity
rechargeable batter)' may be used as, e.g., a power source for driving a motor of hybrid
vehicles or the like.
[0004] Recently, a high power rechargeable battery using a non-aqueous electrolyte and
having high energy density has been considered, and the high power rechargeable
battery may be configured such that a plurality of rechargeable batteries are connected
in series for high power so as to be used as a power source for driving a motor of a
device requiring a large amount of electric power, e.g., electric vehicles or the like.
[0005] In addition, a high-capacity rechargeable battery may include a plurality of
rechargeable batteries connected in series, and the rechargeable battery may have a
cylindrical shape, a prismatic shape, or the like.
[0006] The above information disclosed in this Background section is only for
enhancement of understanding of the background of the described technology and
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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
[0007] Embodiments are directed to a rechargeable battery having a current distribution
member.
[0008] The embodiments may be realized by providing a rechargeable battery including
an electrode assembly including a first electrode and a second electrode; a case
accommodating the electrode assembly; a cap assembly coupled with the case, the cap
assembly including a terminal; a first current collecting member, the first current
collecting member including a ftise portion connecting the terminal with the first
electrode, and an electrode bonding portion fixed to the electrode assembly, the fuse
portion having a lower melting point than other portions of the first current collecting
member; and a current distribution member fixed to the first current collecting member,
the current distribution member electrically connecting the first current collecting
member with the case.
[0009] The cap assembly may include a cap plate coupled with the case, and a
connecting member that electrically connects the terminal with the cap plate.
[0010] The connecting member may be coated with a resistive layer, the resistive layer
being formed of a synthetic resin.
[0011] The rechargeable batteiy may further include a safety member that is electrically
connected to the second electrode, the safety member being between the electrode
assembly and the case.
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[0012] The safety member may include a safety member side plate that faces a flat side
surface of the electrode assembly, and a fixing tab that protrudes from the safety
member side plate and that is attached to the electrode bonding portion, a surface of the
safety member side plate that faces the electrode assembly including an insulating film
thereon.
[0013] The current distribution member may be fixed to the first current collecting
member at a connecting path that is between the fuse portion and the electrode assembly.
[0014] The current distribution member may include a current collecting memberfixing
portion that is fixed to the first current collecting member, and a case fixing
portion that is fixed to the case.
[0015] The first current collecting member may include a terminal bonding portion that
is bonded to the terminal, and a current collecting member side plate that is bent from
the terminal bonding portion and that connects the terminal bonding portion with the
electrode bonding portion.
[0016] The fiise portion may be in the terminal bonding portion.
[0017] The current collecting member-fixing portion may be fixed to the current
collecting member side plate.
[0018] The current collecting member-fixing portion may be fixed to the electrode
bonding portion.
[0019] The case fixing portion may be fixed to a bottom of the case.
[0020] The case fixing portion may be fixed to a lateral side of the case, the lateral side
extending between the cap assembly and a bottom of the case.
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[0021] The current distribution member may include two current collecting memberfixing
portions that are spaced apart from each other, and a lower portion of the current
collecting member side plate may be in a supporting groove that is between the current
collecting member-fixing portions.
[0022] The fuse portion may be enclosed by a heat conductive member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Features will be apparent to those of skill in the art by describing in detail
exemplary embodiments with reference to the attached drawings in which:
[0024] FIG. 1 illustrates a perspective view of a rechargeable batter)' according to a first
exemplary embodiment.
[0025] FIG. 2 illustrates a cross-sectional view of FIG. 1 taken along the line II—II.
[0026] FIG. 3 illustrates an exploded perspective view of electrode assemblies and a
current collecting member according to the first exemplary embodiment.
[0027] FIG. 4 illustrates a perspective view of a current distribution member according
to the first exemplary embodiment.
[0028] FIG. 5 illustrates a schematic diagram showing an electrical interconnection
configuration of the rechargeable battery according to the first exemplary embodiment.
[0029] FIG. 6A illustrates a drawing showing temperature distribution of the current
collecting member according to Comparative Example 1, FIG. 6B illustrates a drawing
showing temperature distribution of the current collecting member according to
Comparative Example 2, and FIG. 6C illustrates a drawing showing temperature
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distribution of the current collecting member according to the first exemplary
embodiment.
[0030] FIG. 7 illustrates a drawing showing temperature distribution of the current
distribution member according to the first exemplary embodiment.
[0031] FIG. 8 illustrates a graph showing joule heat generated in the current collecting
members according to passage of time.
[0032] FIG. 9 illustrates a graph showing temperature distribution of parts of the
rechargeable battery.
[0033] FIG. 10 illustrates a partial cross-sectional view of a rechargeable battery
according to a second exemplary embodiment.
[0034] FIG. 11 illustrates a perspective view of a current distribution member according
to the second exemplary embodiment.
[0035] FIG. 12 illustrates a partial cross-sectional view of a rechargeable battery
according to a third exemplary embodiment.
[0036] FIG. 13 illustrates a perspective view of a current distribution member according
to the third exemplary embodiment.
DETAILED DESCRIPTION
[0037] Example embodiments will now be described more Hilly hereinafter with
reference to the accompanying drawings; however, they may be embodied in different
forms and should not be construed as limited to the embodiments set forth
herein. Rather, these embodiments are provided so that this disclosure will be thorough
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and complete, and will fully convey exemplary implementations to those skilled in the
art.
[0038] In the drawing figures, the dimensions of layers and regions may be exaggerated
for clarity of illustration. Like reference numerals refer to like elements throughout.
[0039] FIG. 1 illustrates a perspective view of a rechargeable battery according to a first
exemplary embodiment, and FIG. 2 illustrates a cross-sectional view of FIG. I taken
along the line IT-IT.
[0040] Referring to FIGS. 1 and 2, the rechargeable battery 101 according to the first
exemplary embodiment may include an electrode assembly 10 (formed by winding a
positive electrode (a first electrode) 11 and a negative electrode (a second electrode) 12
with a separator 13 therebetween), a case 26 accommodating the electrode assembly 10,
and a cap assembly 30 combined to or coupled with the case 26 at an opening in the
case 26.
[0041] The rechargeable battery 101 according to the present exemplary embodiment is
exemplarily illustrated as a prismatic-shaped lithium ion rechargeable battery.
[0042] However, the embodiments are not limited thereto, and it may be applied to
various types of batteries such as a lithium polymer battery, a cylindrical battery, or the
like.
[0043] The positive electrode 11 and the negative electrode 12 may include coated
regions (where an active material is coated on a current collector formed of a thin metal
foil), and uncoated regions 1 la and 12a (where the active material is not coated thereon).
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[0044] The positive electrode uncoated region 1 la may be at one lateral end of the
positive electrode 11 along a lengthwise direction thereof, and the negative electrode
uncoated region I2a may be at another lateral end of the negative electrode 12 along a
lengthwise direction thereof.
[0045] The positive electrode 11 and the negative electrode 12 may be wound while
interposing the separator 13, which functions as an insulator, between them.
[0046] In an implementation, 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.
[0047] A plurality of electrode assemblies 10 may be provided in the case 26, and, e.g.,
the number of electrode assemblies 10 disposed therein may a multiple of 2.
[0048] The case 26 may have a cuboid shape, and one side thereof may have an
opening.
[0049] The case 26 may be formed of, e.g., a metal such as aluminum, stainless steel, or
the like.
[0050] The cap assembly 30 may include a cap plate 31 (that covers the opening of the
case 26), a first terminal 21 (that protrudes out of the cap plate 31 to be electrically
connected to the positive electrode 11), and a second terminal 22 (that protrudes out of
the cap plate 31 to be electrically connected to the negative electrode 12).
[0051] The cap plate 31 may have an elongated plate shape that is oblong in one
direction and is coupleable with the opening of the case 26.
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[0052] The cap plate 31 may include 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 includes a notch 39a.
[0053] The first and second terminals 21 and 22 may protrude above the cap plate 31.
[0054] The first terminal 21 may be electrically connected to the positive electrode 11
through a first current collecting member 41, and the second terminal 22 may be
electrically connected to the negative electrode 12 through a second current collecting
member 42.
[0055] In an implementation, the first terminal 21 may be electrically connected to the
negative electrode, and the second terminal 22 may be electrically connected to the
positive electrode.
[0056] The first terminal 21 may have a rectangular plate shape.
[0057] The first terminal 21 may be electrically connected to the positive electrode 11
through a connecting terminal 25 that is bonded to the first current collecting
member 41.
[0058] The connecting terminals 25 that are respectively combined to or coupled with
the first and second terminals 21 and 22 may have the same structure.
[0059] A sealing gasket 59 for sealing may be provided between the first terminal 21
and the cap plate 31 to be inserted into a hole thiough which the connecting terminal 25
penetrates, and a lower insulating member 43 may be provided under the cap plate 31 to
support the first current collecting member 41.
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[0060] A connection member 58 may be provided under the first terminal 21 to
electrically connect the first terminal 21 with the cap plate 31.
[0061] In an implementation, the cap plate 31 and the case 26 may be positively
charged.
[0062] Current may flow from the positive electrode 11 to the case 26 by way of the
first current collecting member 41, the connecting terminal 25, the first terminal 21, and
the cap plate 31.
[0063] A resistive layer 57 may be coated on a surface of the connection member 58.
In an implementation, the resistive layer 57 may be formed of a synthetic resin, e.g.,
polytetrafluomethylene (Teflon) or the like.
[0064] Once the resistive layer 57 is formed, resistance between the connection member
58 and the cap plate 31 may increase when a short-circuit current flows.
[0065] For example, a voltage applied to the first current collecting member 41, which
is connected in series with the connection member 58, may decrease, and an excessive
increase in temperature of the first current collecting member 41 may be reduced and/or
prevented.
[0066] The second terminal 22 may have a rectangular plate shape.
[0067] The second terminal 22 may be electrically connected to the negative electrode
12 through the connecting terminal 25 that is bonded to or coupled with the second
current collecting member 42.
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[0068] The connecting terminal 25 may penetrate through the cap plate 31 and the
second terminal 22 such that its upper portion is fixed to or coupled with the second
terminal 22.
[0069] A sealing gasket 55 for sealing may be provided between the second terminal 22
and the cap plate 31 to be inserted into a hole through which the connecting terminal 25
penetrates, and a lower insulating member 45 may be provided under the cap plate 31 to
insulate the second terminal 22 from the second current collecting member 42.
[0070] In an implementation, a short-circuit protrusion may be formed at a bottom of
the second terminal 22 and may protrude toward a short-circuit hole 37.
[0071] The second terminal 22 may be elongated in one direction so as to cover the
short-circuit hole 37.
[0072] An upper insulating member 54 may be between the second terminal 22 and the
cap plate 31, e.g.* for insulation.
[0073] The cap assembly 30 may include a short-circuit member 56 (for short-circuiting
the positive electrode 11 with the negative electrode 12), the short-circuit member 56
may be electrically connected to the cap plate 31, and may be deformed to be connected
to the second terminal 22 when the internal pressure of the rechargeable battery 101
increases.
[0074] The short-circuit hole 37 may be formed in the cap plate 31, and the short-circuit
member 56 may be between the upper insulating member 54 and the cap plate 31 at the
short-circuit hole 37.
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[0075] The short-circuit member 56 may include 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.
[0076] When a gas is generated due to an abnormal reaction in the rechargeable batteiy
101, the internal pressure of the rechargeable battery 101 may increase.
[0077] 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 short-circuit member 56 contact each other
to cause a short-circuit.
[0078] FIG. 3 illustrates an exploded perspective view of electrode assemblies and a
current collecting member according to the first exemplary embodiment, and FIG. 4
illustrates a perspective view of a current distribution member according to the first
exemplaiy embodiment.
[0079] Referring to FIGS. 3 and 4, the first current collecting member 41 may include a
terminal bonding portion 41a (that is bonded to the connecting terminal 25), a first
current collecting member side plate 41c (that is bent toward a bottom of the case 26
from the terminal bonding portion 41a), and an electrode bonding portion 41b (that is
eiongated toward the bottom of the case 26 and extends from the first current collecting
member side plate 41c).
[0080] The terminal bonding portion 41a may have a quadrangular plate shape, and
may be fixed to the bottom of the connecting terminal 25 by, e.g., welding.
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[0081] The terminal bonding portion 41a may include a coupling hole 4Id, and the
connecting terminal 25 and the terminal bonding portion 41a may be welded to each
other after the protrusion of the connecting terminal 25 is fitted into the coupling
hole4Id.
[0082] The first current collecting member side plate 41c may be bent at one end
portion of the terminal bonding portion 41a, and may be parallel with lateral sides of the
case 26.
[0083] The first current collecting member 41 may include, e.g., two electrode bonding
portions 41b, and the electrode bonding portions 41b may be bonded to or coupled with
the positive electrode uncoated region 1 la and may be bent from the first current
collecting member side plate 4lc to be parallel with the positive electrode uncoated
region I la.
[0084] The electrode bonding portions 41b may be respectively bonded to or coupled
with the positive electrode uncoated regions 1 la of the different electrode assemblies 10
by, e.g., welding.
[0085] The terminal bonding portion 41a may include a fuse hole 41e, and lateral ends
of the fuse hole 41e may include a fuse portion 4 If having a smaller cross-sectional area
than other adjacent portions thereof
[0086] Having a lower melting point than the other portions, the fiise portion 41f may
be melted earlier than the adjacent portions when an overcurrent flows due to, e.g., a
short-circuit, thereby cutting off the current.
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[0087] The fuse portion 41f may include a heat conductive member 46, and the heat
conductive member 46 may be formed of a polymer having superior heat conductivity
and high heat resistance. For example, the heat conductive member may have high heat
conductivity and may not be susceptible to adverse effects of large amounts of heat.
[0088] For example, the heat conductive member 46 may be formed of a polyimide (PI),
and the heat conductive member 46 may be formed by coating such that it may enclose
the fiise portion 4If and the adjacent portions of the fuse portion 41f.
[0089] The second current collecting member 42 may include a terminal bonding
portion 42a that is bonded to or coupled with the connecting terminal 25, a second
current collecting member side plate 42c that is bent toward the bottom of the case 26
from the terminal bonding portion 42a, and an electrode bonding portion 42b that is
elongated toward the bottom of the case 26 and extends from the second current
collecting member side plate 42c.
[0090] The terminal bonding portion 42a has a quadrangular plate shape, and may be
fixed to the bottom of the connecting terminal 25 by, e.g., welding.
[0091] The terminal bonding portion 42a may include a coupling hole 42d, and the
connecting terminal 25 and the terminal bonding portion 42a may be welded to each
other after the protrusion of the connecting terminal 25 is fitted into the coupling
hole 42d.
[0092] The second current collecting member side plate 42c may be bent at one end
portion of the terminal bonding portion 42a, and may be parallel with lateral sides of the
case 26.
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[0093] The second current collecting member 42 may include, e.g., two electrode
bonding portions 42b, and the electrode bonding portions 42b may be bonded to or
coupled with the negative electrode uncoated region 12a while being bent from the
second current collecting member side plate 42c to be parallel with the negative
electrode uncoated region 12a.
[0094] The electrode bonding portions 42b may be respectively bonded to or coupled
with the negative electrode uncoated regions I2a of the different electrode assemblies
10 by, e.g., welding.
[0095] In an implementation, the first current collecting member 41 may be fixed to a
current distribution member 60 that electrically connects the case 26 with the first
current collecting member 41.
[0096] As shown in FIG. 4, the current distribution member 60 may include current
collecting member-fixing portions 61 that are spaced apart from one another, a
connecting portion 63 that downwardly extends toward the bottom of the case 26 from
the current collecting member-fixing portions 61, and a case fixing portion 64 that is
bent from the connecting portion 63 to be fixed to the bottom of the case 26.
[0097] Each current collecting member-fixing portion 61 may have a plate shape, and
may include a supporting groove 62 between the current collecting member-fixing
portions 61.
[0098] A lower end of the first current collecting member side plate 41c of the first
current collecting member 41 may be inserted into the supporting groove 62, and the
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current collecting member-fixing portion 61 may be bonded to or coupled with the side
plate 41c by, e.g., welding.
[0099] The current distribution member 60 may be fixed to the first current collecting
member 41 in anelectrical connection path between the fiise portion 41 f and the
electrode assembly 10. For example, the fiise portion 41 f may be closer to the first
terminal 21 than a bonded or fixed portion of the current distribution member 60 and
the first current collecting member 41.
[00100] For example, the first current collecting member side plate 41c may be the
portion where the current distribution member 60 and the first current collecting
member 41 are bonded or fixed.
[00101] For example, the fuse portion 41f may be between the portion where the first
terminal 21, the current distribution member 60, and the first current collecting member
41 are bonded.
[00102] The connecting portion 63 may have a bar shape, and may electrically connect
the current collecting member-fixing portion 63 with the case fixing portion 64.
[00103] The case fixing portion 64 may be bent at the connecting portion 63, and may
then be parallel with the bottom of the case 26 so as to be bonded thereto by, e.g.,
welding.
[00104] The current may flow from the positive electrode 11 to the case by way of the
first current collecting member 41 and the current distribution member 60.
[00105] In the rechargeable battery 101 according to the present exemplary embodiment,
the current may flow to the case through, e.g., two different paths. The two paths may
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include, e.g., a first path from the first current collecting member 41 to the case 26 by
way of the connecting terminal 25, the first terminal 21, and the cap plate 31 > and a
second path from the first current collecting member 41 to the case 26 by way of the
current distribution member 60.
[00106] When a first resistor (formed of a path from the first current collecting member
41 to the case 26 via the first terminal) has a first resistance, and a second resistor
(formed of a path Com the first current collecting member 41 to the case 26 via the
current distribution member 60) has a second resistance, the first and second resistances
may be equal to or only slightly different from each other.
[00107] For example, in order for the current to flow through both the path via the
current distribution member 60 and the path via the first terminal 21, the resistances for
the two paths may be equal to or similar to each other.
[00108] If the resistance of one path were to be much higher than that of the other path,
the current may only flow through the path having a lower resistance, and may not flow
through the other path, and the current may not be properly distributed.
[00109] It may be very difficult to make the resistances of the two paths exactly identical.
Accordingly, a resistance difference may be in a predetermined range.
[00110] Even if the resistance of one path is smaller than the other, when the resistance
difference is in the predetermined range, the resistance of one path may increase due to,
e.g., a temperature increase as a result of a current flow, such that the resistances of the
both paths may be equal to each other, thereby distributing the current through both
paths.
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[00111] For example, the resistance difference may be variously set according to an
amount of the short-circuit current and resistivity of the current collecting member.
[00112] The resistance of the second path may be controlled by, e.g., varying a thickness
and/or a length of the current distribution member 60.
[00113] The rechargeable battery 101 according to the present exemplary embodiment
may further include a safety member on an external surface of the electrode assemblies
10, and the safety member may include a first safety member 71 at one exterior side of
the stacked electrode assemblies 10, and a second safety member 72 at another exterior
side of the electrode assemblies 10.
[00114] The first safety member 71 may be between one front or wide side surface of the
case 26 and the electrode assembly 10, and the second safety member 72 may be
between another front or wide side surface of the case 26 and the electrode assembly 10.
[00115] The first safety member 71 may contact an external surface of the electrode
assembly 10.
[00116] The first safety member 71 may include a first safety member side plate 71a
facing a flat, e.g., side, surface of the electrode assembly 10 that is directed toward or
that faces the case, and a fixing tab 71c that protrudes from the first safety member side
plate 71a and that is attached to the electrode bonding portion 42b.
[00117] In the present specification, the flat surface may refer to a smooth external
ciicumferential surface of the electrode assembly 10, other than upper and lower curved
portions thereof.
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[00118] The first safety member side plate 71a and the fixing tab 71c may be formed of,
e.g., a conductive metal plate such as copper, stainless steel, or the like.
[00119] An insulating film 71b may be attached to a surface of the first safety member
side plate 71a that faces the electrode assembly 10.
[00120] The insulating film 71b may be formed of a polymer material, and may help
prevent the first safety member side plate 71a from directly contacting the first
electrode assembly 10.
[00121] The second safety member 72 may face the first safety member 71 with the
electrode assemblies 10 therebetween.
[00122] The second safety member 72 may face the flat surface of the electrode
assembly 10 that faces the case 26.
[00123] The second safety member 72 may include a second safety member side plate
72a attached to or facing the flat surface of the electrode assembly that faces outwardly
from the electrode assembly 10, and a fixing tab 72c that protrudes from the second
safety member side plate 72a and that is coupled with the electrode bonding portion 42b.
[00124] The second safety member side plate 72a and the fixing tab 72c may be formed
of, e.g., a conductive metal plate such as copper, stainless steel, or the like.
[00125] An insulating film 72b may be attached to a surface of the second safety
member side plate 72a that faces the electrode assembly 10.
[00126] The insulating film 72b may be formed of a polymer material, and may help
prevent the second safety member side plate 72a from directly contacting the first
electrode assembly 10.
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[00127] The first and second safety members 71 and 72 may be negatively charged and,
as shown in FIG. 5, when a conductive foreign object 75 penetrates therethrough, the
first safety member 71 or second safety member 72 may be electrically connected to the
case 26 through the conductive foreign object 75.
[00128] In this case, the charged current in the electrode assembly 10 may flow to the
case 26, and the current may flow from the first current collecting member 41 to the
case via the first terminal 21 or via the current distribution member 60.
[00129] Without the current distribution member 60, the fuse portion 41 f may be melted
by overheating, e.g., due to overcurrent during the short circuit. Thus, when the
conductive foreign object 75 penetrates, the current may not flow through the first
current collecting member 41.
[00130] Accordingly, an excessive amount of heat may be generated inside the electrode
assembly 10 because the short-circuit current may flow inside the electrode assembly 10.
[00131] When the connection member 58 is coated with the resistive layer 57 so as to
help prevent the excessive amount of heat from being generated in the fuse portion 4 If,
the heat generated from the fuse portion may be decreased.
[00132] However, when only the resistive layer 57 is coated, energy dissipation of the
fuse portion 41f may be too small and a large amount of heat may be generated in the
electrode assembly 10.
[00133] However, as shown in the present exemplary embodiment, when the current is
distributed to the current distribution member 60, the fuse portion 41 f may be sustained
until the short-circuit current is completely discharged, in addition to helping to prevent
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the large amount of heat from being generated in the electrode assembly 10 by
dissipating it through the fuse portion 41f and the current distribution member 60.
[00134] FIG. 6A illustrates a drawing showing temperature distribution of the current
collecting member according to a Comparative Example 1, FIG. 6B illustrates a
drawing showing temperature distribution of the current collecting member according to
a Comparative Example 2, and FIG. 6C illustrates a drawing showing temperature
distribution of the current collecting member according to the first exemplary
embodiment.
[00135] In addition, FIG. 7 illustrates a drawing showing temperature distribution of the
current distribution member according to the first exemplary embodiment.
[00136] Referring to FIGS. 6A to 6C, the rechargeable battery of Comparative Example
1 (in which the connecting member was not formed with the resistive layer and was not
provided with the current distribution member) and the rechargeable battery of
Comparative Example 2 (in which the connection member was formed with the
resistive member but was not provided with the current distribution member) were
tested.
[00137] In addition, the rechargeable battery of the first exemplary embodiment was
provided with the connection member including the resistive layer and the current
distribution member.
[00138] As shown in FIG. 6A, it may be seen that the current collecting member of the
rechargeable battery of Comparative Example 1 had a 700 °C portion that was higher
than a melting point of aluminum (650 °C), and it may be seen that the current
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collecting member of the rechargeable battery of Comparative Example 2 had a
maximum temperature of 50 °C.
[00139] In contrast, it may be seen that the current collecting member of the
rechargeable battery according to the present exemplary embodiment had a maximum
temperature of 130 °C.
[00140] It may be seen that the temperature of the current collecting member exceeded
the melting point of aluminum in the case of Comparative Example 1, and the
temperature of the current collecting member was very low in the case of Comparative
Example 2.
[00141] In addition, it may be seen that the current collecting member of the present
exemplary embodiment had a lower temperature than Comparative Example 1 and a
higher temperature than Comparative Example 2.
[00142] Further, according to the present exemplary embodiment, as shown in FIG. 7, a
large amount of the current flowed to the current distribution member 60, and the
temperature of the current distribution member 60 increased up to 500 °C.
[00143] However, the temperature ofthe current distribution member 60 was maintained
lower than the melting point of aluminum.
[00144] As shown in the first exemplary embodiment, if an amount of heat discharged
through the current distribution member 60 is increased, a voltage applied to the
electrode assembly 10 may decrease with the same amount of current, thereby
decreasing the amount of heat generated in the electrode assembly 10.
-22-
[00145] FIG. 8 illustrates a graph showing joule heat generated outside ofthe electrode
assembly according to passage of time, and FIG. 9 illustrates a graph showing
temperature distribution of rechargeable battery parts.
[00146] As shown in FIG. 8, it may be seen that a larger amount of joule heat was
generated outside ofthe first current collecting member 41 ofthe first exemplary
embodiment than that of Comparative Example 2.
[00147] A larger amount of joule heat was generated outside ofthe electrode assembly
10 of Comparative Example 1 than that ofthe first exemplary embodiment. But, as
shown in FIG. 6A, the temperature ofthe first current collecting member 41 was higher
than the melting point of aluminum (650 °C).
[00148] Further, as shown in FIG. 9, in the case ofthe first exemplary embodiment, the
heat was distributed to the current collecting member 41 and the current distribution
member 60, and the heat was stably discharged while temperatures ofthe parts were
maintained below respective melting points.
[00149] FIG. 10 illustrates a partial cross-sectional view of a rechargeable battery
according to a second exemplary embodiment, and FIG. 11 illustrates a perspective
view of a current distribution member according to the second exemplary embodiment.
[00150] Referring to FIGS. 10 and II, a rechargeable battery 102 according to the
present exemplary embodiment may have the same general structure as the rechargeable
batter>' according to the aforementioned first exemplary embodiment, except for a
current distribution member 80, so a repeated description ofthe same structure may be
omitted.
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[00151] A current distribution member 80 may be fixedly provided on, e.g., fixed to, the
first current collecting member 41 to electrically connect the case 26 and the first
current collecting member 41.
[00152] The current distribution member 80 may include current collecting memberfixing
portions 81 that are spaced apart from one another, a connecting portion 83 that
downwardly extends toward the bottom of the case 26 from the current collecting
member-fixing portions 81, an inclined portion 85' that is slantedly bent, e.g., bent at an
inclined angle, from the connecting portion 83, and a case fixing portion 84 that is bent
at the connecting portion 83 to be fixed to the bottom of the case 26.
[00153] Each current collecting member-fixing portion 81 may have a plate shape, the
current distribution member 80 may have two current collecting member-fixing portions
81 that are spaced apart from each other, and the current collecting member-fixing
portions 81 may include a supporting groove 82 therebetween.
[00154] A lower end of the first current collecting member side plate 41c of the first
current collecting member 41 may be inserted in the supporting groove 82, and the
current collecting member-fixing portion 81 may be bonded to or coupled with the first
current collecting member side plate 41c by, e.g., welding.
[00155] The connecting portion 83 may have a bar shape, and may extend in a
heightwise direction of the case 26.
[00156] The inclined portion 85 may be formed such that it is slantedly bent, with
respect to a lengthwise direction of the connecting portion 83, from the connecting
portion 83 toward a lateral side of the case 26.
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[00157] Here, the lateral side of the case may refer to a side thereof that extends from the
bottom of the case 26 and faces a lateral side end portion of the electrode assembly 10.
[00158] The case fixing portion 84 may be bent, e.g., slantedly bent, from the inclined
portion 85, and may be bonded to a lateral side lower end of the case 26 by, e.g.,
welding, while being while being parallel with the lateral side of the case 26.
[00159] FIG. 12 illustrates a partial cross-sectional view of a rechargeable battery
according to a third exemplary embodiment of, and FIG. 13 illustrates a perspective
view of a current distribution member according to the third exemplary embodiment.
[00160] Referring to FIGS. 12 and 13, the rechargeable battery 103 according to the
present exemplary embodiment may have the same general structure as the rechargeable
battery according to the aforementioned first exemplary embodiment, except for a
current distribution member 90, so a repeated description of the same structure may be
omitted.
[00161] The first current collecting member 41 may be fixedly provided with, e.g., fixed
to, a current distribution member 90 that electrically connects the case 26 with the first
current collecting member 41.
[00162] The current distribution member 90 may include current collecting memberfixing
portions 91 that are spaced apart from one another, a connecting portion 93 that
downwardly extends toward the bottom of the case 26 from the current collecting
member-fixing portions 91, and a case fixing portion 94 that is bent from the connecting
portion 93 an fixed to the bottom of the case 26.
- 2 5 -
[00163] Each current collecting member-fixing portion 91 may have a plate shape, and
two current collecting member-fixing portions 91 may be spaced apart from one another
to face each other.
[00164] The current collecting member-fixing portions 91 may include a supporting
groove 92 therebetween, and a lateral side end portion of the electrode assemblies 10
may be inserted in the supporting groove 92.
[00165] The current collecting member-fixing portion 91 may be fixed to the first current
collecting member 41 such that it is fixed to the electrode bonding portion 41b of the
first current collecting member 41 by, e.g., welding.
[00166] The fuse portion 41f may be closer to the first terminal 21 than a bonded portion
of the current distribution member 90 and the first current collecting member 41.
[00167] For example, the electrode bonding portion 41b may refer to the bonded portion
of the current distribution member 90 and the first current collecting member 41.
[00168] The connecting portion 93 may have a bar shape, and may extend in a
heightwise direction of the case 26.
[00169] The case fixing portion 94 may be bent from the connecting portion 93 and may
be bonded to the bottom of the case 26 by, e.g., welding, while being parallel thereto.
[00170] By way of summation and review, if a short-circuit were to occur inside a
rechargeable battery or external foreign objects were to cause a short-circuit, an
overcurrent may flow in the rechargeable battery.
-26-
[00171] If the overcurrent continuously flows therein, excessive heat may be generated
inside the rechargeable battery, thereby causing explosion or ignition of the
rechargeable battery.
[00172] The embodiments may provide a rechargeable battery that can distribute a shortcircuit
current (and heat associated therewith) if an external short-circuit occurs.
[00173] According to an embodiment, the current distribution member may be provided
to distribute an overcurrent (and heat associated therewith) generated when a shortcircuit
occurs.
[00174] Accordingly, in addition to helping to reduce the likelihood of and/or prevent
the fuse portion from being overheated, the battery according to an embodiment may
help prevent the electrode assembly from being overheated because heat discharging is
induced through the current distribution member.
[00175] Example embodiments have been disclosed herein, and although specific terms
are employed, they are used and are to be interpreted in a generic and descriptive sense
only and not for purpose of limitation. In some instances, as would be apparent to one
of ordinary skill in the art as of the filing of the present application, features,
characteristics, and/or elements described in connection with a particular embodiment
may be used singly or in combination with features, characteristics, and/or elements
described in connection with other embodiments unless otherwise specifically indicated.
Accordingly, it will be understood by those of skill in the art that various changes in
form and details may be made without departing from the spirit and scope of the present
invention as set forth in the following claims.
-27-
[00176]
[00177] 101, 102, 103: rechargeable battery 10: electrode assembly
[00178] 11: positive electrode 1 la: positive electrode imcoated region
[00179] 12: negative electrode 12a: negative uncoated region
[00180] 13: separator 21: first terminal
[00181] 22: second terminal 25: connecting terminal
[00182] 26: case 30: cap assembly
[00183] 31: cap plate 32: electrolyte injection opening
[00184] 34: vent hole 37: short-circuit hole
[00185] 38: sealing cap 39: vent plate
[00186] 41: first current collecting member
[00187] 42: second current collecting member
[00188] 41a, 42a: terminal bonding portion
[00189] 41b, 42b: electrode bonding portion
[00190] 41c, 42c: current collecting member side plate 41d, 42d: coupling hole
[00191] 4Ie: fuse hole 4If: fuse portion
[00192] 42: second current collecting member
[00193] 43: lower insulating member
[00194] 45: lower insulating member 54: upper insulating member
[00195] 55: sealing gasket 56: short-circuit member
[00196] 58: connecting member 59: sealing gasket
[00197] 60, 80, 90: current distribution member
-28-
[00198] 61, 81, 91: current collecting member-fixing portion
[00199] 62, 82, 92: supporting groove 63, 83, 93: connecting portion
[00200] 64, 84, 94: case fixing portion 71: first safety member
[00201] 71a, 72a: safety member side plate 71b, 72b: insulating film
[00202] 71c, 72c: fixing tab 72: second safety member
[00203] 85: inclined portion

WHAT IS CLAIMED IS:
1. A rechargeable battery, comprising:
an electrode assembly including a first electrode and a second electrode;
a case accommodating the electrode assembly;
a cap assembly coupled with the case, the cap assembly including a terminai;
a first current collecting member, the first current collecting member including:
a fuse portion connecting the terminal with the first electrode, and
an electrode bonding portion fixed to the electrode assembly, the fiise
portion having a lower melting point than other portions of the first current
collecting member; and
a current distribution member fixed to the first current collecting member, the
current distribution member electrically connecting the first current coilecting member
with the case.
2. The rechargeable battery as claimed in claim 1, wherein the cap
assembly includes:
a cap plate coupled with the case, and
a connecting member that electrically connects the terminal with the cap plate.
3. The rechargeable battery of claim 2, wherein the connecting member is
coated with a resistive layer, the resistive layer being formed of a synthetic resin.
-30-
4. The rechargeable battery as claimed in claim 2, further comprising a
safety member that is eleetricaiiy connected to the second electrode, the safety member
being between the electrode assembly and the case.
5. The rechargeable battery as claimed in claim 4, wherein the safety
member includes:
a safety member side plate that faces a flat side surface of the electrode
assembly, and
a fixing tab that protrudes from the safety member side plate and that is attached
to the electrode bonding portion, a suriace of the safety member side plate that faces the
electrode assembly including an insulating film thereon.
6. The rechargeable battery as claimed in claim 1, wherein the current
distribution member is fixed to the first current collecting member at a connecting path
that is between the fiise portion and the electrode assembly.
7. The rechargeable battery as claimed in claim 6, wherein the current
distribution member includes:
a current collecting member-fixing portion that is fixed to the first current
collecting member, and
a case fixing portion that is fixed to the case.
-31 -
8. The rechargeable battery as claimed in claim 7, wherein the first current
collecting member includes:
a terminal bonding portion that is bonded to the terminal, and
a current collecting member side plate that is bent from the terminal bonding
portion and that connects the terminal bonding portion with the electrode bonding
portion.
9. The rechargeable battery as claimed in claim 8, wherein the fuse portion
is in the terminal bonding portion.
10. The rechargeable battery as claimed in claim 9, wherein the current
collecting member-fixing portion is fixed to the current collecting member side plate.
11. The rechargeable battery as claimed in claim 9, wherein the current
collecting member-fixing portion is fixed to the electrode bonding portion.
12. The rechargeable battery as claimed in claim 9, wherein the case fixing
portion is fixed to a bottom of the case.
13. The rechargeable battery as claimed in claim 9, wherein the case fixing
portion is fixed to a lateral side of the case, the lateral side extending between the cap
assembly and a bottom of the case.
14. The rechargeable battery as claimed in claim 9, wherein:
the current distribution member includes two current collecting member-fixing
portions that are spaced apart from each other, and
a lower portion of the current collecting member side plate is in a supporting
groove-that is between the current collecting member-fixing portions.
15. The rechargeable battery as claimed in claim 1, wherein the fuse portion
is enclosed by a heat conductive member.