BATTERY UNIT AND BATTERY MODULE USING THE SAME
1. Field
[0001] One or more embodiments of the present invention relate to a battery unit
and a battery module using a plurality of the battery units coupled with each other.
BACKGROUND
2. Description of the Related Art
[0002] In general, secondary batteries can be discharged and recharged
repeatedly, unlike primary batteries that are not designed to be recharged. Secondary
batteries are used as energy sources for mobile devices, electric vehicles, hybrid cars,
electric bikes, uninterruptable power supplies, etc. Also, secondary batteries are used
in the form of a single battery or a battery module in which a plurality of batteries are
electrically coupled in a single unit by using a bus bar, in accordance with the type of
external device adopting the secondary battery.
[0003] A compact mobile device such as a mobile phone with output and capacity
of a single battery may operate for a predetermined time. However, when longer
duration operations or high power operations are needed, as in electric vehicles or
hybrid cars, a battery module is often used to prevent an output or capacity problem.
The battery module may increase an output voltage or an output current according to
the number of batteries included in the battery module. The battery module may reach
a desired output voltage or output current by coupling a plurality of batteries in series
or in parallel.
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SUMMARY
[0004] One or more embodiments of the present invention include a battery unit
having an improved electrode temriinal assembly, which may reduce manufacturing
costs, and a battery module using the battery unit.
[0005] Additional aspects of embodiments of the present invention will be set forth
in part in the description which follows and. In part, will be apparent from the
description, or may be learned by practice of the presented embodiments of the
present invention.
[0006] According to one or more embodiments of the present invention, a battery
unit includes a case accommodating an electrode assembly, the case having an
opening, and a cap plate covering the opening, the cap plate having a temriinal
insertion portion. The battery unit may further include a terminal member inserted into
the case through the terminal insertion portion from an outside of the case and coupled
to the electrode assembly, the terminal member including a current collector electrically
coupled to the electrode assembly; a terminal portion extending parallel to an upper
surface of the cap plate to an outside of the cap plate; and a connection portion
electrically coupled to the current collector and to the terminal portion. The battery unit
further includes a fixing member in the terminal insertion portion fixing the terminal
member to the cap plate, the fixing member having injection-molded plastic resin in the
terminal insertion portion and surrounding the terminal member..
[0007] The terminal portion may be separated from the upper surface of the cap
plate.
[0008] The terminal portion may extend in a direction along a major side of the cap
plate.
[0009] The connection portion may include a first bending portion extending
downwardly from the terminal portion, and a second bending portion extending in the
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direction along the major side from the first bending portion. In some embodiments,
the current collector may extend downwardly from an edge of the second bending
portion in a direction along a minor side of the cap plate.
[0010] The second bending portion may be partially buried in the fixing member.
[0011] The second bending portion may be entirely buried in the fixing member.
[0012] The fixing member may include a first fixing portion filling the temiinal
insertion portion, and a second fixing portion filling a gap between the temriinal portion
and the upper surface of the cap plate.
[0013] The second fixing portion may extend to an upper portion of the first fixing
portion.
[0014] The second fixing portion may be located over an edge of the terminal
insertion portion.
[0015] The terminal member may include a positive terminal member and a
negative tennina! member.
[0016] The positive terminal member and the negative terminal member may each
include a metal. In some embodiments, the metal of the positive terminal member and
the negative terminal member is the same.
[0017] The positive terminal member and the negative terminal member may
include dissimilar metals.
[0018] The positive terminal member may include aluminum (Al) and the negative
terminal member may include copper (Cu).
[0019] The battery unit may include a welding layer on an upper surface of one of
the positive terminal member or the negative terminal member. In some embodiments,
the welding layer may include the same metal as that of any one of the positive
terminal member or the negative terminal member and may be located on an upper
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surface of the other one of the positive terminal member or the negative terminal
member including a dissimilar metal than the welding layer.
[0020] According to one or more embodiments of the present invention, a battery
module includes a plurality of battery units and a bus bar. The battery units of the
plurality of battery units each includes a case accommodating an electrode assembly,
the case having an opening, and a cap plate covering the opening, the cap plate
having a terminal insertion portion. Each battery unit may further include a tennlnal
member inserted into the case through the terminal insertion portion from an outside of
the case and coupled to the electrode assembly, the tenninal member including a
current collector electrically coupled to the electrode assembly; a terminal portion
extending parallel to an upper surface of the cap plate to an outside of the cap plate;
and a connection portion electrically coupled to the current collector and to the terminal
portion. Each battery unit further includes a fixing member in the terminal insertion
portion fixing the terminal member to the cap plate, the fixing member having injectionmolded
plastic resin in the terminal insertion portion and surrounding the terminal
member. The bus bar may couple the terminal portions of the battery units of the
plurality of battery units to respective neighboring battery units of the plurality of battery
units.
[0021] The terminal portion of each of the battery units of the plurality of battery
units may be separated from the upper surface of its respective cap plate.
[0022] The terminal portion of each of the battery units of the plurality of battery
units may extend in a direction along a major side of its respective cap plate.
[0023] The fixing member of each battery unit of the plurality of battery units may
include a first fixing portion filling the terminal insertion portion and a second fixing
portion filling a gap between the terminal portion and the upper surface of the cap
plate.
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[0024] The second fixing portion of the fixing member may extend to an upper
portion of the first fixing portion.
[0025] The second fixing portion of the fixing member may be located over an edge
of the terminal insertion portion.
[0026] The bus bar of the battery module may be welded to the tenninal portions.
[0027] The tenninal member of each of the battery units of the plurality of battery
units may include a positive terminal member and a negative terminal member.
[0028] The positive terminal member and the negative terminal member of the
terminal member may include dissimilar metals.
[0029] The bus bar of the battery module may include a same metal as either of the
positive terminal member or the negative tenninal member of the tenninal member.
[0030] The battery units of the plurality of battery units may each further include a
welding layer on an upper surface of one of the positive terminal member or the
negative terminal member. In some embodiments, the welding layer may include the
same metal as that of the bus bar and may be located on an upper surface of one of
the positive terminal member or the negative terminal member, including a metal
different from that of the welding layer and the bus bar.
[0031] The positive terminal member may include aluminum (Al) and the negative
terminal member may include copper (Cu); the bus bar may include Al, and the
welding layer including Al may be on an upper surface of a terminal portion of the
negative terminal member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] These and/or other aspects of embodiments of the present invention will
become apparent and more readily appreciated from the following description of the
embodiments, taken in conjunction with the accompanying drawings, of which:
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[0033] FIG. 1 is an exploded perspective view of a battery unit according to an
embodiment of the present invention;
[0034] FIG. 2 is a cross-sectional view taken along the line X-X' of FIG. 1;
[0035] FIG. 3 is a perspective view illustrating an example of an electrode
assembly;
[0036] FIG. 4 is a perspective view illustrating a negative (positive) terminal member
according to an embodiment of the present invention;
[0037] FIGS. 5A to 5C are perspective views illustrating arrangements of a positive
terminal member and a positive current collector and a negative terminal member and
a negative current collector where the current collectors are coupled on the same
surface of an electrode assembly;
[0038] FIGS. 6A to 6C are perspective views illustrating arrangements of a positive
terminal member and a positive current collector and a negative terminal member and
a negative current collector where the current collectors are coupled on different
surfaces of an electrode assembly;
[0039] FIGS. 7A to 7C illustrate an example of a process for fixing a positive
terminal member and a negative tenninal member to a cap plate, and for forming a
fixing member through an insert injection molding method;
[0040] FIG. 8 is a perspective view of a battery module according to an embodiment
of the present invention;
[0041] FIG. 9 is a perspective view of terminal members according to another
embodiment of the present invention;
[0042] FIG. 10 is a cross-sectional view illustrating a battery unit according to an
embodiment of the present invention;
[0043] FIG. 11 is a perspective view illustrating a part of a cap assembly of FIG. 10;
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[0044] FIG. 12 is a cross-sectional view illustrating an example of a process for
fixing a positive terminal member and a negative terminal member on the cap plate by
an insert injection molding method and for forming the fixing member of FIG. 10; and
[0045] FIG. 13 is a perspective view illustrating a part of a cap assembly according
to another embodiment of the present invention.
DETAILED DESCRIPTION
[0046] Reference will now be made in detail to embodiments, examples of which
are illustrated in the accompanying drawings, wherein like reference numerals refer to
the like elements throughout. In this regard, the present embodiments may have
different fonns and should not be construed as being limited to the descriptions set
forth herein. Accordingly, the embodiments are merely described below, by referring to
the figures, to explain aspects of the present description. As used herein, the term
"and/or" includes any and all combinations of one or more of the associated listed
items. Expressions such as "at least one of," when preceding a list of elements, modify
the entire list of elements and do not modify the individual elements of the list. As used
herein, the temri "plurality" means greater than one.
[0047] FIG. 1 is an exploded perspective view of a battery unit 1 according to an
embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the
line X-X' of FIG. 1. FIG. 3 is a perspective view illustrating an example of an electrode
assembly 10. Referring to FIGS. 1 and 2, the battery unit 1 includes an electrode
assembly 10, a case 20 for accommodating the electrode assembly 10, and a cap
assembly 30 for closing an upper end of the case 20.
[0048] The battery unit 1 may be a secondary battery such as a lithium ion battery.
The battery unit 1 may include a variety of battery unit types such as a cylindrical
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battery unit, a prismatic battery unit, or a polymer battery unit. However, the present
invention is not limited to any one of the above battery unit types.
[0049] Referring to FIG. 3, the electrode assembly 10 may include a positive plate
11, a negative plate 12, and a separator 13 interposed between the positive plate 11
and the negative plate 12. For example, a stack body of the positive plate 11, the
negative plate 12, and the separator 13 may be wound in a jelly-roll shape.
[0050] In some embodiments, the positive plate 11 includes a positive current
collector portion 11a and a positive active material layer 1 l b on at least one surface of
the positive current collector portion 11a. In some embodiments, a positive material
uncoated portion 11c where the positive active material layer 1 lb is not coated is at an
edge portion of the positive current collector portion 11a in a widthwise direction
thereof. In some embodiments, the negative plate 12 includes a negative current
collector portion 12a and a negative active material layer 12b on at least one surface of
the negative current collector portion 12a. In some embodiments, a negative material
uncoated portion 12c where the negative active material layer 12b is not coated is at
an edge portion of the negative current collector portion 12a in a widthwise direction
thereof. The positive material uncoated portion 11c and the negative material
uncoated portion 12c may be arranged to be separated from each other in a widthwise
direction of the electrode assembly 10. For example, the positive material uncoated
portion 11c and the negative material uncoated portion 12c may be arranged at
opposite edge portions of the electrode assembly 10 in the widthwise direction.
[0051] The cap assembly 30 includes a cap plate 310, temriinal members 320 and
330 that are electrically coupled to the electrode assembly 10, and terminal fixing
members 340 and 350 for fixing the terminal members 320 and 330 to the cap plate
310.
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[0052] The case 20 has an opening 21 for inserting the electrode assembly 10. The
opening 21 is closed as the cap plate 310 is coupled to the case 20. In some
embodiments, an edge 311 of the cap plate 310 is shape-matched with an upper edge
22 of the ease 20 that forms the opening 21. In this embodiment, as the cap plate 310
is coupled to the case 20 by, for example, laser welding, a housing for accommodating
the electrode assembly 10 is formed. The cap plate 310 includes a safety vent 32.
The safety vent 32 may be designed to be breakable to provide a gas exhaust path
when the internal pressure of the case 20 exceeds a preset point. The cap plate 310
includes an electrolyte injection hole 33 for injecting an electrolyte into the case 20.
When the injection of an electrolyte is completed, the electrolyte injection hole 33 is
closed by a sealing plug 34.
[0053] The terminal members 320 and 330 may be a positive terminal member 320
and a negative terminal member 330, respectively. In some embodiments, the
terminal members 320 and 330 may be a negative terminal member 320 and a positive
terminal member 330, respectively. The positive terminal member 320 and the
negative terminal member 330 are electrically coupled to the positive material
uncoated portion 11c and the negative material uncoated portion 12c, respectively, of
the electrode assembly 10. The positive material uncoated portion 11c and the
negative material uncoated portion 12c of the electrode assembly 10 may be
electrically exposed to an outside of the case 20 via the positive terminal member 320
and the negative terminal member 330. Terminal insertion portions 35 and 36 may be
a positive terminal insertion portion 35 and a negative terminal insertion portion 36,
respectively. The terminal insertion portions 35 and 36 are formed by vertically
penetrating the cap plate 310. The positive terminal member 320 and the negative
terminal member 330 may be inserted into the terminal insertion portions 35 and 36,
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respectively, and fixed to the cap plate 310 by the positive terminal fixing member 340
and the negative terminal fixing member 350, respectively.
[0054] FIG. 4 is a perspective view illustrating the negative (positive) terminal
member 330 (320) according to an embodiment of the present invention. In most
embodiments, the terminal members 320 and 330 have the same shape or shapes
symmetrical to each other. In FIG. 4, reference numerals of constituent elements
forming the positive terminal member 320 are indicated in parentheses together with
the reference numerals of constituent elements of the negative terminal member 330.
[0055] Referring to FIGS. 1, 2, and 4, the positive terminal member 320 may
include a positive terminal portion 321, a positive current collector 324, and a positive
connection portion 325, coupling the positive terminal portion 321 and the positive
current collector 324. The negative terminal member 330 may include a negative
terminal portion 331, a negative current collector 334, and a negative connection
portion 335, coupling the negative terminal portion 331 and the negative current
collector 334. The negative terminal portion 331 and the positive tenninal portion 321
extend parallel to an upper surface 312 of the cap plate 310. The positive terminal
member 320 and the negative terminal member 330 may be a metal having electrical
conductivity. For example, the positive terminal member 320 and the negative terminal
member 330 may be formed by cutting and bending a metal panel member into a
desired shape by a processing method that includes pressing.
[0056] In one embodiment, the negative terminal portion 331 extends in a first
direction, for example a horizontal direction, along a major side of the cap plate 310.
The negative current collector 334 may extend in a second direction, for example
downwardly, in a direction along the thickness direction of the cap plate 310. The
negative connection portion 335 may be bent from the negative tenninal portion 331 to
couple the negative terminal portion 331 and the negative current collector 334. The
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negative connection portion 335 may include a first negative bending portion 332 bent
in the second direction, for example downwardly, from an edge 331a of the negative
terminal portion 331 in a third direction, for example in a direction opposite to the first
direction, and extended therefrom; and a second negative bending portion 333 bent in
the third direction from an edge 332a of the first negative bending portion 332 in the
second direction and extended therefrom. The negative current collector 334 may be
bent in the second direction, for example downwardly, from an edge 333a of the
second negative bending portion 333 in a fourth direction, for example in a direction
crossing the first and second directions, in a minor side direction of the cap plate 310,
and extended therefrom.
[0057] In one embodiment, a large area portion 334b, and not a thickness portion
334c, of the negative current collector 334 is located parallel to the negative material
uncoated portion 12c of the electrode assembly 10. A width W of the large area
portion 334b may be detennined such that a contact area between the large area
portion 334b and the negative material uncoated portion 12c is as large as possible.
Thus, in this embodiment, a large contact area between the negative current collector
334 and the negative material uncoated portion 12c may be achieved, reducing contact
resistance.
[0058] FIGS. 5A to 5C are perspective views illustrating arrangements of the
positive terminal member 320 and the positive current collector 324, and the negative
terminal member 330 and the negative current collector 334. In FIGS. 5A to 5C, the
positive current collector 324 and the negative current collector 334 are coupled on a
same surface of the electrode assembly 10.
[0059] Referring to FIG. 5A, the positive terminal member 320 and the negative
terminal member 330 may be arranged such that the positive terminal portion 321 and
the negative terminal portion 331 face each other. Referring to FIG. 5B, the positive
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terminal member 320 and the negative tenninal member 330 may be arranged such
that the positive tenninal portion 321 and the negative terminal portion 331 face
opposite directions. In the embodiments illustrated in FIGS. 5A and 5B, the positive
terminal member 320 and the negative tenninal member 330 have symmetrical shapes
with respect to a major side direction along the cap plate 310. Referring to FIG. 5C,
the positive tenninal member 320 and the negative terminal member 330 may be
arranged such that the positive terminal portion 321 and the negative terminal portion
331 face the same direction. In this embodiment, the shapes of the positive terminal
member 320 and the negative terminal member 330 are the same.
[0060] FIGS. 6A to 6C are perspective views illustrating arrangements of the
positive terminal member 320 and the positive current collector 324 and the negative
terminal member 330 and the negative current collector 334. In FIGS. 6A to 6C, the
positive current collector 324 and the negative current collector 334 are coupled on
different surfaces of the electrode assembly 10. In the embodiments illustrated in
FIGS. 6A and 6B, the positive terminal member 320 and the negative terminal member
330 have the same shape. In the embodiment illustrated in FIG. 6C, the shapes of the
positive terminal member 320 and the negative terminal member 330 are symmetrical
to each other with respect to the major side direction along the cap plate 310.
[0061] In embodiments where the shape of the positive terminal member 320 is the
same as that of the negative terminal member 330, as illustrated in FIG. 4, for
example, the positive terminal member 320 includes the positive terminal portion 321
extending in the first direction, the positive current collector 324 extending in the
second direction, and the positive connection portion 325 bending from the positive
terminal portion 321 and coupling the positive terminal portion 321 and the positive
current collector 324. The positive connection portion 325 may include a first positive
bending portion 322 that is bent in the second direction from an edge 321a of the
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positive terminal portion 321 in the third direction and extended therefrom, and a
second positive bending portion 323 that is bent in the third direction from an edge
322a of the first positive bending portion 322 in the second direction and extended
therefrom. The positive current collector 324 may be bent in the second direction from
an edge 323a of the second positive bending portion 323 in the fourth direction.
[0062] In some embodiments, a large area portion 324b, and not a thickness
portion 324c, of the positive current collector 324 is located parallel to the positive
material uncoated portion 11c of the electrode assembly 10. The width W of the large
area portion 324b may be determined such that a contact area between the large area
portion 324b and the positive material uncoated portion 11c is as large as possible.
Thus, in this embodiment, a large contact area between the positive current collector
324 and the positive material uncoated portion 11c may be achieved, thereby reducing
contact resistance.
[0063] In embodiments where the shape of the positive terminal member 320 is
symmetrical to the shape of the negative terminal member 330, as indicated by a
dotted line of FIG. 4, for example, the positive current collector 324 may be bent in the
second direction from a second edge 323b of the second positive bending portion 323
in a fifth direction that is opposite to the fourth direction and extended therefrom.
[0064] In some embodiments, the positive terminal member 320 and the negative
terminal member 330 are respectively inserted in the positive temiinai insertion portion
35 and the negative terminal insertion portion 36. In these embodiments, the positive
terminal portion 321 and the negative terminal portion 331 are located above the cap
plate 310, whereas the positive current collector 324 and the negative current collector
334 are located under the cap plate 310. In these embodiments, the positive terminal
member 320 and the negative terminal member 330 are respectively fixed to the cap
plate 310 by a positive terminal fixing member 340 and a negative terminal fixing
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member 350 that are respectively inserted into the positive terminal insertion portion 35
and the negative temiinal insertion portion 36. The positive temriinal fixing member
340 and the negative terminal fixing member 350 may be fomned of, for example,
electrical insulation plastic. The positive terminal portion 321 and the negative terminal
portion 331 may protrude above from the cap plate 310. In some embodiments, gaps
G1 and G2 are respectively formed between an upper surface 312 of the cap plate 310
and the positive temiinal portion 321 and the negative terminal portion 331,
respectively. Accordingly, the positive terminal portion 321 and the negative terminal
portion 331 may be fixed to the cap plate 310, and the positive terminal portion 321
and the negative terminal portion 331 may be electrically insulated from the cap plate
310 by the positive terminal fixing member 340 and the negative terminal fixing
member 350, respectively.
[0065] The electrical insulation may include a plastic. For example, in some
embodiments, the electrical insulation includes common plastics such as polyvinyl
chloride (PVC), polystyrene, high density polyethylene, and acrylonitrile butadiene
styrene copolymer (ABS); common engineering plastics such as polyacetal,
polyphenylene oxide (PPO), polyphenylene ether (PRE), polyamide (PA),
polycarbonate (PC), and polybutylene terephthalate (PBT); high performance
engineering plastics such as U-polymer, polysulfone (PSU), polyphenylene sulfide
(PPS), polyetherimide (PEI), polyethersulfone (PES), polyacrylate,
polyetheretherketone (PEEK), and polytetrafluoroethylene (PTFE); and super heat
resisting engineering plastics such as polyamide-imide (PAI) and polyimide (PI). In
one embodiment, the positive terminal fixing member 340 and the negative terminal
fixing member 350 may be formed of resin produced by adding 40% fiberglass to PPS.
[0066] The positive terminal fixing member 340 and the negative terminal fixing
member 350 may be formed by an insert injection molding method. In some
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embodiments, this method includes inserting the positive terminal member 320 and the
negative terminal member 330, into the positive terminal insertion portion 35 and the
negative terminal insertion portion 36, respectively. The method further may include
injecting a material such as an electrical insulation, for example the resin produced by
adding 40% fiberglass to PPS describe above, to mold into the positive terminal
insertion portion 35 and the negative terminal insertion portion 36. For example, the
embodiments shown in FIGS. 7A to 7C illustrate an example of a process for fixing the
positive terminal member 320 and the negative terminal member 330 to the cap plate
310, and forfonning the positive and negative terminal fixing members 340 and 350
through an insert injection molding method.
[0067] Referring to FIG. 7A, an upper core 1001 and a lower core 1002 of an
injection mold may be separated from each other, thereby opening the injection mold.
In some embodiments, the cap plate 310 is placed on a lower parting line PL2 of the
lower core 1002, and the positive terminal member 320 and the negative terminal
member 330 are inserted into the lower core 1002 by passing through the cap plate
310 via the positive terminal insertion portion 35 and the negative terminal insertion
portion 36, respectively. Support holes 1002a and 1002b for respectively supporting
the positive current collector 324 and the negative current collector 334 may be
provided in the lower core 1002. In these embodiments, when the positive current
collector 324 and the negative current collector 334 are supported by the support holes
1002a and 1002b, respectively, the positive terminal portion 321 and the negative
terminal portion 331 are separated from the upper surface 312 of the cap plate 310.
To prevent gaps 1009 and 1010 between each of the positive terminal portion 321 and
the negative terminal portion 331 and the upper surface 312 of the cap plate 310 from
being filled with, for example the plastic resin, the gaps 1009 and 1010 may be filled
with the upper core 1001. The gaps 1009 and 1010 correspond to under-cut portions
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with respect to an operational direction of the upper core 1001. The gaps 1009 and
1010 may be filled with slide cores 1003 and 1004 that move in a direction crossing the
operational direction of the upper core 1001 when operated. In other words, when the
upper core 1001 approaches or is separated from the lower core 1002, the slide cores
1003 and 1004 may move in the direction crossing the operational direction of the
upper core 1001, thereby filling the gaps 1009 and 1010 or move in a direction away
from the gaps 1009 and 1010, respectively.
[0068] Referring to the embodiment illustrated in FIG. 7B, the upper core 1001
approaches the lower core 1002 once the cap plate 310, the positive temninal member
320, and the negative terminal member 330, are supported on the lower core 1002.
When the upper core 1001 and the lower core 1002 are coupled to each other, molding
spaces 1005 and 1006, where the positive temninal fixing member 340 and the
negative terminal fixing member 350, respectively, are to be formed, may be defined
by an upper parting line PL1 and the lower parting line Pl_2. In these embodiments,
the gaps 1009 and 1010 are filled by the slide cores 1003 and 1004, respectively. In
these embodiments, the molding spaces 1005 and 1006 are filled with a material, for
example resin, through gates 1007 and 1008. In these embodiments, once a
predetermined cooling time has passed and the material, for example resin, filling the
molding spaces 1005 and 1006 has cured, the positive temninal fixing member 340 and
the negative terminal fixing member 350, fixing the positive terminal member 320 and
the negative terminal member 330 to the cap plate 310, are formed.
[0069] Next, referring to the embodiment illustrated in FIG. 7C, the upper core 1001
is separated from the lower core 1002, and the cap assembly 30 is separated from the
lower core 1002.
[0070] Referring back to FIG. 2, the positive terminal portion 321 and the negative
terminal portion 331 may be separated from the upper surface 312 of the cap plate
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310, fomning gaps G1 and G2 therebetween. The gaps G1 and G2 may be the same.
The positive terminal fixing member 340 and the negative terminal fixing member 350
partially or entirely surround the positive connection portion 325 and the negative
connection portion 335, respectively. Gaps between the positive connection portion
325 and the negative connection portion 335, and edges of the positive terminal
insertion portion 35 and the negative terminal insertion portion 36 of the cap plate 310,
are filled with a material, for example a resin, forming the positive terminal fixing
member 340 and the negative terminal fixing member 350, respectively. Accordingly,
in these embodiments, the positive temninal member 320 and the negative terminal
member 330 may be electrically and entirely insulated from the cap plate 310. The
second positive bending portion 323 and the second negative bending portion 333 may
be partially or entirely (refer to the dashed line of FIG. 2) buried in the positive tenninal
fixing member 340 and the negative terminal fixing member 350, respectively. In these
embodiments, as the positive connection portion 325 and the negative connection
portion 335, each having bending portions, are buried in the positive terminal fixing
member 340 and the negative terminal fixing member 350, respectively, the positive
terminal member 320 and the negative tenninal member 330 are each respectively
coupled to the cap plate 310 by the positive terminal fixing member 340 and the
negative terminal fixing member 350, thereby improving a coupling strength between
each of the positive terminal member 320 and the negative terminal member 330 with
the cap plate 310.
[0071] The completed cap assembly 30 may include the electrode assembly 10, the
positive terminal member 320, and the negative terminal member 330 electrically
coupled to one another. In some embodiments, the positive current collector 324 is
electrically coupled to the positive material uncoated portion 11c, whereas the negative
current collector 334 is electrically coupled to the negative material uncoated portion
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12c. The coupling of the positive current collector 324 to the positive material
uncoated portion 11c and the coupling of the negative current collector 334 to the
negative material uncoated portion 12c may be, for example, by ultrasound welding.
[0072] Once the cap assembly 30 and the electrode assembly 10 are coupled to
each other, the electrode assembly 10 may be inserted into the case 20 through the
opening 21. In these embodiments, once the cap plate 310 is coupled to the case 20
by, for example, a laser welding method, the opening 21 is closed, electrically exposing
the electrode assembly 10 to the outside of the case 20 via the positive terminal
member 320 and the negative temriinal member 330. After the opening 21 is closed,
an electrolyte may be injected through the electrolyte injection hole 33, and the
electrolyte injection hole 33 may be closed by using the sealing plug 34, thus
completing the manufacturing of the battery unit 1.
[0073] According to the above-described battery unit 1, each of the positive terminal
member 320 and the negative terminal member 330 may be formed by a single metal
plate. In other words, all components of the positive terminal member 320 and the
negative terminal member 330 from the positive current collector 324 and the negative
current collector 334 to the positive teminal portion 321 and the negative terminal
portion 331 may be formed of the same metal. Thus, since the positive terminal
member 320 and the negative terminal member 330 may be formed without the need
for a coupling process by welding, etc., the manufacturing cost may be reduced while
maintaining an electrical characteristic of a current path from the positive current
collector 324 and the negative current collector 334 to the positive terminal portion 321
and the negative terminal portion 331, respectively. Also, as the positive terminal
member 320 and the negative terminal member 330 are coupled to the cap plate 310
by the insert injection molding method using, for example plastic or resin, the cap plate
310 may be coupled to the respective positive terminal member 320, negative terminal
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member 330, with an electrical insulation therebetween. Also, in embodiments where
the positive txerminal portion 321 and the negative terminal portion 331 extend in a
direction parallel with each other and with the upper surface 312 of the cap plate 310,
for example in a horizontal direction,, this may allow for a more streamlined coupling of
the positive terminal portion 321 and the negative terminal portion 331 of neighboring
battery units 1 forming a battery module 2 as illustrated in FIG. 8, and described below.
Also, the positive terminal portion 321 and the negative terminal portion 331,
extending, for example, in a horizontal direction, may be advantageous in allowing a
sufficient area for welding.
[0074] FIG. 8 is a perspective view of the battery module 2 according to an
embodiment of the present Invention. Referring to FIG. 8, the battery module 2 may
include a plurality of battery units 1 arranged in a row. For example, the battery
module 2 may include the battery units 1 arranged in one direction or in a stacked
structure, arranging the battery units 1 in one or more rows.
[0075] The battery units 1 may be electrically coupled to one another in series or in
parallel by coupling the positive terminal portion 321 and the negative terminal portion
331 of neighboring battery units 1. For example, as illustrated in FIG. 8, the battery
units 1 may be coupled to each other in series by coupling the terminal portions of
different polarities of a pair of neighboring battery units 1 by using a bus bar 400. In
this embodiment, the battery units 1 may be arranged such that the polarities of the
terminal portions thereof are alternately arranged in a coupling direction A of the bus
bar 400. The bus bar 400 may be coupled to the positive tenninal portion 321 and the
negative terminal portion 331 by welding, for example. Although it is not illustrated in
FIG. 8, the battery units 1 may be coupled in parallel to each other by coupling the
terminal portions of the same polarity of a pair of neighboring battery units 1 by using a
bus bar 400.
20
w
[0076] The bus bar 400 may be formed of a metal material exhibiting superior
conductivity. Also, the bus bar 400 may be formed of a metal material having a
uniform composition. When the positive terminal portion 321 and the negative terminal
portion 331 each are formed of a similar metal to that of the bus bar 400, each of the
positive terminal portion 321 and the negative terminal portion 331 and the bus bar 400
may be coupled by welding the similar metals. In some embodiments, the similar
metal may include, for example, aluminum (Al) and/or copper (Cu).
[0077] The positive terminal portion 321 and the negative terminal portion 331 may
be formed of dissimilar metals. When the bus bar 400 is formed of a metal material
different from those of the positive terminal portion 321 and/or the negative terminal
portion 331, the coupling between these dissimilar metals may be formed between the
positive terminal portion 321 and the bus bar 400 and between the negative terminal
portion 331 and the bus bar 400, respectively. When the bus bar 400 is formed of a
similar metal as any one of the positive terminal portion 321 and/or the negative
terminal portion 331, the coupling between dissimilar metals may be between the bus
bar 400 and the other, not similar metal, one of the positive terminal portion 321 and
the negative terminal portion 331.
[0078] For example in one embodiment, laser welding between similar metals may
result in a sufficient welding strength; example similar metals may include AI-AI or Cu-
Cu. However, if the laser welding in these embodimetns is between dissimilar metals
such as Al-Cu, for example, weldability is degraded and a sufficient welding strength
may not be achieved. In embodiments having dissimilar metals, friction stir welding
(FSW) may be performed instead of laser welding. FSW uses a welding tool (not
shown) inserted in a base member rotated at a high speed. The base members
around the welding tool may be softened due to frictional heat between the welding
tool and the base members. A flow of the base members, such as plastic, resulting
21
#
from an agitation operation by the rotating welding tool allows two base members to be
forcibly mixed with each other with respect to a boundary surface of the two base
members. Thus, FSW may provide a sufficient welding strength between dissimilar
metals that have lower weldability.
[0079] For example, in one embodiment, the positive temninal portion 321 may be
formed of Al that is electrochemically suitable for a positive electrode, the negative
terminal portion 331 may be formed of Cu that is electrochemically suitable for a
negative electrode, and the bus bar 400 may be formed of Al. The positive terminal
portion 321 and the bus bar 400 may be coupled by laser welding, whereas the
negative terminal portion 331 and the bus bar 400 may be coupled by FSW.
Accordingly, in this embodiment, a sufficient welding strength may result between the
bus bar 400 and each of the positive terminal portion 321 and the negative terminal
portion 331. In other embodiments, both of the positive temiinal portion 321 and the
negative terminal portion 331 may be coupled to the bus bar 400 by FSW.
[0080] FIG. 9 is a perspective view of the positive temiinal member 320 and the
negative terminal member 330 applied to the battery unit 1, according to another
embodiment of the present invention. When the positive terminal portion 321 and the
negative terminal portion 331 are of dissimilar metals, and the bus bar 400 is of a metal
that is the same as any one of the positive terminal portion 321 and the negative
terminal portion 331, the other one of the positive terminal portion 321 and the negative
terminal portion 331 may include a welding layer 326 or 336 of a similar metal to the
bus bar 400. For example, when the positive terminal portion 321 is formed of Al that
is electrochemically suitable for a positive electrode, the negative temiinal portion 331
may be formed of Cu that is electrochemically suitable for a negative electrode, and
the bus bar 400 may be fomned of Al, the welding layer 336 formed of Al that is the
same as the bus bar 400 may be on an upper surface of the negative terminal member
22
t
330. When the bus bar 400 is formed of Cu, the welding layer 326 formed of Cu that is
the same as the bus bar 400 may be on the upper surface of the positive terminal
portion 321. The welding layers 326 and 336 may be on the positive terminal portion
321 and the negative terminal portion 331, respectively, by laser welding or FSW. In
some embodiments, the gaps G1 and G2, illustrated in FIG. 2, may be different from
each other to allow for the final heights of the upper surfaces of the positive terminal
portion 321 and the negative terminal portion 331 to be the same. According to the
above embodiment, since the coupling between the bus bar 400 and each of the
positive terminal portion 321 and the negative terminal portion 331 is between similar
metals, a sufficient welding strength may result even by laser welding.
[0081] FIG. 10 is a cross-sectional view illustrating the battery unit 1 according to an
embodiment of the present invention. FIG. 11 is a perspective view illustrating a part
of the cap assembly 30 of FIG. 10. Referring to FIGS. 10 and 11, the positive terminal
fixing member 340 and the negative terminal fixing member 350 are respectively
located between the positive terminal insertion portion 35 and the negative terminal
insertion portion 36, and the gaps G1 and G2 between the positive terminal portion 321
and the negative temiinal portion 331 and the upper surface 312 of the cap plate 310.
In other words, the positive terminal fixing member 340 and the negative terminal fixing
member 350 respectively include first fixing portions 341 and 351 that fill the positive
terminal insertion portion 35 and the negative terminal insertion portion 36, and second
fixing portions 342 and 352 that fill the gaps G1 and G2 between each of the positive
terminal portion 321 and the negative terminal portion 331 and the upper surface 312
of the cap plate 310.
[0082] The positive and negative terminal fixing members 340 and 350 may be
formed by an insert injection molding method. For example, as illustrated in FIG. 12, in
embodiments where the upper core 1001 and the lower core 1002 of an injection mold
23
ii
are separated from each other, opening the mold, the cap plate 310 is inserted in the
lower core 1002, and the positive terminal member 320 and the negative terminal
member 330 are inserted into the lower core 1002 by penetrating the cap plate 310
respectively via the positive terminal insertion portion 35 and the negative terminal
insertion portion 36. Then, the upper core 1001 may approach the lower core 1002.
When the upper core 1001 and the lower core 1002 are coupled to each other, molding
spaces 1005 and 1006, where the positive and negative terminal fixing members 340
and 350 are respectively formed, are defined by the upper parting line PL1 and the
lower parting line PL2. Gaps 1009 and 1010 between the positive terminal portion 321
and the negative terminal portion 331, respectively, and the upper surface 312 of the
cap plate 310 are coupled to the respective molding spaces 1005 and 1006, thereby
allowing the gaps 1009 and 1010 to be filled with a material, for example with resin. In
some embodiments, a resin is injected into the molding spaces 1005 and 1006 and the
gaps 1009 and 1010 via the gates 1007 and 1008. In these embodiments, once a
predetermined cooling time has passed and the material, for example resin, filling the
molding spaces 1005 and 1006 and the gaps 1009 and 1010 has cured, the positive
and negative terminal fixing members 340 and 350, respectively, including the first
fixing portions 341 and 351 and the second fixing portions 342 and 352 that fix the
positive and negative terminal members 320 and 330 to the cap plate 310, are fomned.
Next, the upper core 1001 may be separated from the lower core 1002, and the cap
assembly 30 may be separated from the lower core 1002.
[0083] According to these embodiments, the coupling strength between the cap
plate 310 and each of the positive terminal member 320 and the negative terminal
member 330 may be improved. In other words, as the second fixing portions 342 and
352 respectively increase the contact areas between the positive terminal member 320
and the negative terminal member 330with the cap plate 310 and the positive terminal
24
1^
fixing member 340 and the negative terminal fixing member 350, respectively, the
coupling strength between the cap plate 310 and each of the positive terminal member
320 and the positive terminal fixing member 340, and each of the negative terminal
member 330 and the negative terminal fixing member 350 may be improved. Also,
when the bus bar 400 is coupled to the positive terminal portion 321 and the negative
terminal portion 331 by a method such as welding, a downward pressure may be
applied by the welding tool to the positive terminal portion 321 and the negative
terminal portion 331. In this embodiment, since the positive terminal portion 321 and
the negative terminal portion 331 are supported on the cap plate 310 by the second
fixing portions 342 and 352, the possibility that the positive temriinal fixing member 340
and the negative terminal fixing member 350 will separate from the positive terminal
insertion portion 35 and the negative terminal insertion portion 36, respectively, may be
reduced.
[0084] In some embodiments, in a welding process, heat transferred to the positive
terminal portion 321 and the negative terminal portion 331 may be distributed through
the second fixing portions 342 and 352.
[0085] Since the positive terminal portion 321 and the negative terminal portion 331
are supported by the second fixing portions 342 and 352, in some embodiments, the
positive terminal portion 321 and the negative terminal portion 331 may be prevented
from being bent downwardly during the process of welding the bus bar 400.
Accordingly, in these embodiments, the coupling quality between the bus bar 400 and
each of the positive temriinal portion 321 and the negative terminal portion 331 may be
improved. Also, electrical insulation between the cap plate 310 and each of the
positive terminal member 320 and the negative terminal member 330 may be improved
in these embodiments.
25
^
[0086] FIG. 13 is a perspective view illustrating a part of the cap assembly 30
according to another embodiment of the present invention. Referring to FIG. 13, the
second fixing portions 342 and 352 may extend over the first fixing portions 341 and
351, thereby completely covering the positive and negative terminal insertion portions
35 and 36. In other words, the second fixing portions 342 and 352 may extend over
edges 35a and 36a of the positive and negative temninal insertion portions 35 and 36,
respectively, in a major side direction and in a minor side direction of the cap plate 310.
According to the above embodiment, the intrusion of moisture into the case 20 through
the gaps between the positive and negative terminal fixing members 340 and 350 and
the positive and negative terminal insertion portions 35 and 36 is prevented, reducing
the possibility of corrosion of the cap plate 310, the electrode assembly 10, the positive
and negative current collectors 324 and 334, and the case 20.
[0087] It should be understood that the exemplary embodiments described herein
should be considered in a descriptive sense only and not for purposes of limitation.
Descriptions of features or aspects within each embodiment should typically be
considered as available for other similar features or aspects in other embodiments.
The scope of the present disclosure is defined in the claims and their equivalents.
26

WE CLAIM:
1. A battery unit comprising:
a case accommodating an electrode assembly and having an opening;
a cap plate covering the opening, the cap plate having a terminal insertion
portion;
a terminal member inserted into the case through the temninal insertion portion
from an outside of the case and coupled to the electrode assembly, the terminal
member comprising:
a current collector electrically coupled to the electrode assembly;
a temiinal portion extending parallel to an upper surface of the cap plate
to an outside of the cap plate; and
a connection portion electrically coupled to the current collector and to
the terminal portion; and
a fixing member in the terminal insertion portion and fixing the terminal member
to the cap plate, the fixing member comprising injection-molded plastic resin in the
terminal insertion portion and surrounding the terminal member.
2. The battery unit as claimed in claim 1, wherein the temninal portion is
separated from the upper surface of the cap plate.
3. The battery unit as claimed in claim 2, wherein the temriinal portion
extends in a direction along a major side of the cap plate.
4. The battery unit as claimed in claim 3, wherein the connection portion
comprises:
27
a first bending portion extending downwardly from the terminal portion;
and a second bending portion extending in the direction along the major
side from the first bending portion; and
wherein the current collector extends downwardly from an edge of the
second bending portion in a direction along a minor side of the cap plate.
5. The battery unit as claimed in claim 4, wherein the second bending
portion is partially buried in the fixing member.
6. The battery unit as claimed in claim 4, wherein the second bending
portion is entirely buried in the fixing member.
7. The battery unit as claimed in claim 2, wherein the fixing member
comprises a first fixing portion filling the terminal insertion portion and a second fixing
portion filling a gap between the terminal portion and the upper surface of the cap
plate.
8. The battery unit as claimed in claim 7, wherein the second fixing portion
extends to an upper portion of the first fixing portion.
9. The battery unit as claimed in claim 8, wherein the second fixing portion
is located over an edge of the terminal insertion portion.
10. The battery unit as claimed in claim 1, wherein the terminal member
comprises a positive terminal member and a negative terminal member.
28
11. The battery unit as claimed in claim 10, wherein the positive terminal
member and the negative terminal member each comprise a metal, the metal of the
positive terminal member and the negative terminal member being the same.
12. The battery unit as claimed in claim 11, wherein the positive terminal
member and the negative terminal member comprise dissimilar metals.
13. The battery unit as claimed in claim 12, wherein the positive terminal
member comprises aluminum (Al) and the negative terminal member comprises copper
(Cu).
14. The battery unit as claimed in claim 12, wherein the battery unit further
comprises a welding layer on an upper surface of one of the positive terminal member
or the negative terminal member, the welding layer comprising a metal that is the same
metal as that of any one of the positive terminal member or the negative terminal
member and being located on an upper surface of the one of the positive terminal
member or the negative temninal member comprising a dissimilar metal than the
welding layer.
15. A battery module comprising:
a plurality of battery units, the battery units each comprising:
a case accommodating an electrode assembly and having an opening;
a cap plate covering the opening, the cap plate having a terminal
Insertion portion;
29
u 4 1
t}£C 10«
a terminal member inserted into the case through the tenninal insertion
portion from an outside of the case and coupled to the electrode assembly, the
terminal member comprising:
a current collector electrically coupled to the electrode assembly;
a terminal portion extending parallel to an upper surface of the cap
plate to an outside of the cap plate; and
a connection portion electrically coupled to the current collector
and to the terminal portion;
a fixing member in the terminal insertion portion and fixing the terminal
member to the cap plate, the fixing member comprising injection-molded plastic resin
in the terminal insertion portion and surrounding the terminal member; and
a bus bar coupling the terminal portions of the battery units of the plurality of
battery units to respective neighboring battery units of the plurality of battery units.
16. The battery module as claimed in claim 15, wherein the terminal portion
is separated from the upper surface of the cap plate.
17. The battery module as claimed in claim 16, wherein the terminal portion
extends in a direction along a major side of the cap plate.
18. The battery module as claimed in claim 16, wherein the fixing member
comprises:
a first fixing portion filling the terminal insertion portion; and
a second fixing portion that filling a gap between the terminal portion and
the upper surface of the cap plate.
30
19. The battery module as claimed in claim 18, wherein the second fixing
portion extends to an upper portion of the first fixing portion.
20. The battery module as claimed in claim 19, wherein the second fixing
portion is located over an edge of the tenninal insertion portion.
21. The battery module as claimed in claim 15, wherein the bus bar is welded
to the terminal portions.
22. The battery module as claimed in claim 21, wherein the tenninal member
comprises a positive terminal member and a negative terminal member.
23. The battery module as claimed in claim 22, wherein the positive tenninal
member and the negative terminal member comprise dissimilar metals.
24. The battery module as claimed in claim 23, wherein the bus bar
comprises a same metal as either the positive terminal member or the negative
terminal member.
25. The battery module as claimed in claim 24, wherein the battery units
each further comprise a welding layer on an upper surface of one of the positive
terminal member or the negative tenninal member, the welding layer comprising the
same metal as that of the bus bar and being located on an upper surface of one of the
positive terminal member or the negative terminal member comprising a metal different
from that of the welding layer and the bus bar.
31
1>
^ '--^ ^ . ^ r o '0>
26. The battery module as claimed in claim 25, wherein the positive terminal
member comprises aluminum (Al) and the negative terminal member comprises copper
(Cu), the bus bar comprises Al, and the welding layer comprising Al is on the upper
surface of a temriinal portion of the negative terminal member.