CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of the
5 priority of Korean Patent Application Nos. 10-2018-0137484,
filed on November 09, 2018, and 10-2019-0010004, filed on
January 25, 2019, which are hereby incorporated by reference
in their entirety.
10 BACKGROUND OF THE INVENTION
Field, of the invention
[0002] The present invention relates to a pouch forming method
and a pouch forming device.
15 Description of the Related, Art
[0003] Secondary batteries are rechargeable unlike primarily
batteries, and also, the possibility of compact size and high
capacity is high. Thus, recently, many studies on rechargeable
batteries are being carried out. As technology development and
20 demands for mobile devices increase, the demands for
rechargeable batteries as energy sources are rapidly
increasing.
[0004] Rechargeable batteries are classified into coin type
batteries, cylindrical type batteries, prismatic type
25 batteries, and pouch type batteries according to a shape of a
1
battery case. In such a secondary battery, an electrode
assembly mounted in a battery case is a chargeable and
dischargeable power generating device having a structure in
which an electrode and a separator are stacked.
5 [0005] The electrode assembly may be approximately classified
into a jelly-roll type electrode assembly in which a separator
is interposed between a positive electrode and a negative
electrode, each of which is provided as the form of a sheet coated
with an active material, and then, the positive electrode, the
10 separator, and the negative electrode are wound, a stacked type
electrode assembly in which a plurality of positive and negative
electrodes with a separator therebetween are sequentially
stacked, and a stack/folding type electrode assembly in which
stacked type unit cells are wound together with a separation
15 film having a long length.
[0006] Recently, the pouch-type battery in which a
stack/folding type electrode assembly is built in a pouch-type
battery case provided as an aluminum lamination sheet is
attracting'much attention due to its low manufacturing cost,
20 small weight, easy shape deformation, and the like, and thus,
its usage is gradually increasing.
[0007] However, in the process of forming the accommodation
part in a pouch sheet accommodating the electrode assembly so
as to manufacture the secondary battery, a large amount of
25 cracks occur in a portion at which the pouch sheet is formed.
2
[Prior Art Document]
[Patent Document]
Korean Patent Publication No. 10-2014-0015647
5 SmMARY OF THE INVENTION
[0008] One aspect of the prevent invention is to provide a pouch
forming method and device, which are capable of preventing
cracks from occurring when an accommodation part accommodating
an electrode assembly is formed in a pouch sheet.
10 [0009] According to another aspect of the present invention,
there is provided a pouch forming method for forming an
accommodation part accommodating an electrode assembly in a
pouch sheet, the pouch forming method comprising: a seating
process of seating the pouch sheet on a top surface of a lower
15 die in which a forming groove is formed in an upper portion
thereof; a vacuum elongation process of elongating a lower
portion of the pouch sheet, in which the accommodation part is
formed, through vacuum; and an accommodation part formation
process of pressing the portion of the pouch sheet, which is
20 elongated through the vacuum, by using a punch disposed above
the pouch sheet in a direction in which the forming groove is
formed to form the accommodation part.
[0010] According to another aspect of the present invention,
there is provided a pouch forming device for forming an
25 accommodation part accommodating an electrode assembly in a
pouch sheet, the pouch forming device comprising: a lower die
which is disposed on a lower portion of the pouch sheet and in
which a forming groove is formed in an upper portion thereof;
a punch unit disposed above the pouch sheet and comprising a
5 punch pressing the pouch sheet in a direction of the forming
groove of the lower die to form the accommodation part in the
pouch sheet in a shape corresponding to the forming groove; and
a vacuum unit connected to the forming groove of the lower side
to apply vacuum to the pouch sheet seated on a top surface of
10 the lower die so as to elongate the forming portion of the pouch
sheet-
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The above and other aspects, features and other
15 advantages of the present invention will be more clearly
understood from the following detailed description taken in
conjunction with the accompanying drawings, in which:
FIG. 1 is an exploded perspective view of a secondary
battery to which a pouch sheet formed through a pouch forming
20 method is applied according to a first embodiment of the present
invention;
FIG. 2 is a cross-sectional view illustrating an example
of a seating process in the pouch forming method according to
the first embodiment of the present invention;
25 FIG. 3 is a cross-sectional view illustrating an example
4
of a pouch supporting process in the pouch forming method
according to the first embodiment of the present invention;
FIG. 4 is a cross-sectional view illustrating a vacuum
elongation process in the pouch forming method according to the
5 first embodiment of the present invention;
FIG. 5 is a cross-sectional view illustrating an example
of a state in which the pouch sheet is elongated through the
vacuum elongation process in the pouch forming method according
to the first embodiment of the present invention;
10 FIG. 6 is a cross-sectional view illustrating an example
of an accommodation part formation process in the pouch forming
method according to the first embodiment of the present
invention;
FIG. 7 is a cross-sectional view illustrating an example
15 of a state in which an accommodation part is formed in the pouch
sheet through the accommodation part formation process in the
pouch forming method according to the first embodiment of the
present invention;
FIG. 8 is a cross-sectional view illustrating a vacuum
20 elongation process in a pouch forming method according to a
second embodiment of the present invention;
FIG. 9 is a cross-sectional view illustrating an example
of a state in which a pouch sheet is elongated through the vacuum
elongation process in the pouch forming method according to the
25 second embodiment of the present invention;
5
FIG. 10 is a cross-sectional view illustrating an example
of a state in which an accommodation part is formed in the pouch
sheet through the vacuum elongation process and an
accommodation part formation process in the pouch forming
method according to the second embodiment of the present
invention;
FIG. 11 is a cross-sectional view illustrating an example
of a state in which the accommodation part is formed after the
vacuum elongation process and the accommodation part formation
process in the pouch forming method according to the second
embodiment of the present invention;
FIG. 12 is an exploded perspective view illustrating an
example of a pouch forming device used in a pouch forming method
according to a third embodiment of the present invention;
FIG. 13 is a cross-sectional view illustrating an example
of a state in which the pouch sheet is elongated through the
vacuum elongation process in the pouch forming method according
to the third embodiment of the present invention;
FIG. 14 is' a cross-sectional view illustrating an example
of an accommodation part formation process in the pouch forming
method according to the third embodiment of the present
invention;
FIG. 15 is a cross-sectional view illustrating an example
of a state in which an accommodation part is formed in the pouch
sheet through the accommodation part formation process in the
pouch forming method according to the third embodiment of the
present invention;
FIG. 16 is a graph illustrating a relationship between
pressing force and a forming depth of a stripper in the pouch
forming method according to the third embodiment of the present
invention;
FIG. 17 is a graph illustrating a relationship between
a descending speed and a forming depth of a punch in the pouch
forming method according to the third embodiment of the present
invention;
FIG. 18 is a table showing results obtained through
Experimental Example 1 in a pouch forming device according to
a fourth embodiment of the present invention; and
FIG. 19 is a table showing results obtained through
Experimental Example 2 in a pouch forming device according to
a fifth embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED ElfflODIIffiMT
[0012] The objectives, specif ic advantages, and novel features
of the present invention will become more apparent from the
following detailed description taken in conjunction with the
accompanying drawings. It should be noted that the reference
numerals are added to the components of the drawings in the
present specification with the same numerals as possible, even
if they are illustrated In other drawings. Also, the present
7
invention may be embodied m different forms and should not be
construed as limited to the embodiments set forth herein. In
the following description of the present invention, the
detailed descriptions of related arts which may unnecessarily
obscure the gist of the present invention will be omitted.
[0013] FIG. 1 is an exploded perspective view of a secondary
battery to which a pouch sheet formed through a pouch forming
method is applied according to a first embodiment of the present
invention, FIG. 2 is a cross-sectional view illustrating an
example of a seating process in the pouch forming method
according to the first embodiment of the present invention, and
FIG. 3 is a cross-sectional view illustrating an example of a
pouch supporting process in the pouch forming method according
to the first embodiment of the present invention.
[0014] FIG. 4 is a cross-sectional view illustrating a vacuum
elongation process in the pouch forming method according to the
first embodiment of the present invention, FIG. 5 is a
cross-sectional view illustrating an example of a state in which
the pouch"sheet is elongated through the vacuum elongation
process in the pouch forming method according to the first
embodiment of the present invention, and FIG. 6 is a
cross-sectional view illustrating an example of an
accommodation part formation process in the pouch forming
method according to the first embodiment of the present
invention.
[0015] Referring to FIGS. 1 to 5, a pouch forming method for
forming an accommodation part lib accommodating an electrode
assembly 12 in a pouch sheet 11 according to a first embodiment
of the present invention comprises a seating process of seating
5 the pouch sheet 11 on a lower die 110 in which a forming groove
111 is formed, a vacuum elongation process of elongating a
portion of the pouch sheet 11, in which the accommodation part
lib is formed, through vacuum, and an accommodation part
formation process of pressing the portion of the pouch sheet,
10 which is elongated through the vacuum, by using a punch 151 to
form the accommodation part lib. Also, the pouch forming method
according to the first embodiment of the present invention may
further comprise a pouch supporting process supporting the
pouch sheet 11 on the lower die 110 before the vacuum elongation
15 process is performed.
[0016] Hereinafter, the pouch forming method according to the
first embodiment of the present invention will be described in
more detail with reference to FIGS. 1 to 7.
[0017] Referring to FIG. 2, in the seating process, the pouch
20 sheet 11 may be seated on a top surface of the lower die 110
in which a forming groove 111 is formed in an upper portion
thereof. Here, the pouch sheet 11 may cover an upper portion
of the forming groove 111 of the lower side to seal the forming
groove 111.
25 [0018] Also, the pouch sheet 11 may be provided as, for example,
9
a sheet made of aluminum (Al).
[0019] Referring to FIG. 3, in the pouch supporting process,
before the vacuum elongation process is performed, an outer
portion lie of the accommodation part lib in the pouch sheet
5 11 may be pressed through a stripper 121 disposed above the pouch
sheet 11 to support the pouch sheet 11 to the lower die 110 so
that the pouch sheet 11 is fixed. Here, a stripper unit 120
comprising the stripper 121 and a stripper moving part allowing
the stripper 121 to move may be provided (see FIG. 1) .
10 [0020] Thus, when the accommodation part 11 is formed by
pressing the pouch sheet 11 through an accommodation part
formation process that will be described below, the pouch sheet
11 may be prevented from moving.
[0021] Referring to FIGS. 1, 4, and 5, in the vacuum elongation
15 process, the lower portion of the pouch sheet 11, in which the
accommodation part lib is formed, may be elongated through
vacuum.
[0022] Also, in the vacuum elongation process, a space of the
forming groove 111 may be vacuumized through vacuum passages
20 112 and 113 connected to the forming groove 111 in the lower
die 110 to elongate a portion of the pouch sheet 11, which faces
the forming groove 111.
[0023] Furthermore, in the vacuum elongation process, the
space of the forming groove 111 may be vacuumized through
25 suction holes 112a and 113a of the vacuum passages 112 and 113
10
formed in plurality along a lower portion of a side surface of
the forming groove 111 to elongate a forming portion lid of the
pouch sheet 11. Here, in the vacuum elongation process, for
example, the space of the forming groove 111 may be vacuumized
5 through a vacuum unit 130 for 0.1 seconds to 0.2 seconds.
[0024] When the vacuum elongation process is performed before
the accommodation part formation process, elongation
efficiency may be improved. That is, in the vacuum elongation
process, when the pouch sheet 11 is elongated through the vacuum,
10 the elongation efficiency may be improved compared to a case
in which the pouch sheet 11 is elongated through the vacuum
during the accommodation part formation process.
[0025] FIG. 7 is a cross-sectional view illustrating an example
of a state in which an accommodation part is formed in the pouch
15 sheet through the accommodation part formation process in the
pouch forming method according to the first embodiment of the
present invention.
[0026] Referring to FIGS. 6 and 7, in the accommodation part
formation process, the portion of the pouch sheet 11, which is
20 elongated through the vacuum, may be pressed by a punch 151
disposed above the pouch sheet 11 in a direction, in which the
forming groove 111 is formed, to form the accommodation part
lib. Here, the pouch sheet 11 may have a body 11a having a shape
that is convex downward by the punch 151. Here, a punch unit
25 150 comprising the punch 151 and the punch moving part allowing
11
the punch 151 to move may be provided.
[0027] Also, in the accommodation part formation process, the
pouch sheet 11 may be pressed by the punch 151 so that the
accommodation part lib has a depth, for example, 7 mm to 8 mm
5 in the pouch sheet 11.
[0028] Referring to FIGS. 4 to 7, in the above-described pouch
forming method according to the first embodiment of the present
invention, the forming portion lid in which the accommodation
part is formed may be elongated through the vacuum before the
10 accommodation part lib is formed in the pouch sheet 11. Thus,
when the punch 151 is pressed to form the pouch sheet 11,
occurrence of cracks in the forming portion may be prevented.
[0029] Hereinafter, a pouch forming method according to a
second embodiment of the present invention will be described.
15 [0030] FIG. 8 is a cross-sectional view illustrating a vacuum
elongation process in a pouch forming method according to a
second embodiment of the present invention, and FIG. 9 is a
cross-sectional view illustrating an example of a state in which
a pouch sheet is elongated through the vacuum elongation process
20 in the pouch forming method according to the second embodiment
of the present invention.
[0031] FIG. 10 is a cross-sectional view illustrating an
example of a state in which an accommodation part is formed in
the pouch sheet through the vacuum elongation process and an
25 accommodation part formation process in the pouch forming
12
method according to the second embodiment of the present
invention, and FIG. 11 is a cross-sectional view illustrating
an example of-astate in which the accommodation part is formed
after the vacuum elongation process and the accommodation part
formation process in the pouch forming method according to the
second embodiment of the present invention.
[0032] Referring to FIGS. 8 to 11, a pouch forming method for
forming an accommodation part lib accommodating an electrode
assembly in a pouch sheet 11 according to a first embodiment
of the present invention comprises a seating process of seating
the pouch sheet 11 on a lower die 110 in which a forming groove
111 is formed, a pouch supporting process of supporting the
pouch sheet 11 on the lower die 110, a vacuum elongation process
of elongating a portion of the pouch sheet 11, in which the
accommodation part lib is formed, through vacuum, and an
accommodation part formation process of pressing the portion
of the pouch sheet, which is elongated through the vacuum, by
using a punch 151 to form the accommodation part lib. Here,
the vacuum elongation process and the accommodation formation
process may be performed at the same time.
[0033] The pouch forming method according to the second
embodiment of the present invention is different from the pouch
forming method according to the foregoing first embodiment of
the present invention in that the vacuum elongation process and
the accommodation formation process are performed at the same
13
time. Thus, contents of this embodiment,, which are duplicated
with those according to the foregoing first embodiment, will
be briefly described, and also, differences therebetween will
be mainly described.
5 [0034] In more detail, in the vacuum elongation process of the
pouch forming method according to the second embodiment of the
present invention, a lower portion of the pouch sheet 11, in
which the accommodation part lib is formed, may be elongated
through vacuum. Also, in the vacuum elongation process, a space
10 of the forming groove 111 may be vacuumized through vacuum
passages 112 and 113 connected to the forming groove 111 in the
lower die 110 to elongate a portion of the pouch sheet 11, which
faces the forming groove 111.
[0035] Also, in the accommodation part formation process, the
15 portion of the pouch sheet 11, which is elongated through the
vacuum, may be pressed by a punch 151 disposed above the pouch
sheet 11 in a direction, in which the forming groove 111 is formed,
to form the accommodation part lib.
[0036] Here, in the pouch forming method according to the
20 second embodiment of the present invention, the vacuum
elongation process and the accommodation part formation process
may be performed at the same time.
[0037] That is, in the pouch forming method according to the
second embodiment of the present invention, the vacuum may be
25 applied to press the pouch sheet by the punch while elongating
14
the pouch sheet 11, thereby forming the accommodation part lib.
[0038] Thus, the vacuum elongation process and the
accommodation part formation process may be performed at the
same time to reduce a manufacturing time.
5 [0039] Hereinafter, a pouch forming method according to a third
embodiment of the present invention will be described.
[0040] FIG. 12 is an exploded perspective view illustrating
an example of a pouch forming device used in a pouch forming
method according to a third embodiment of the present invention,
10 and FIG. 13 is a cross-sectional view illustrating an example
of a state in which the pouch sheet is elongated through the
vacuum elongation process in the pouch forming method according
to the third embodiment of the present invention.
[0041] FIG. 14 is a cross-sectional view illustrating an
15 example of an accommodation part formation process in the pouch
forming method according to the third embodiment of the present
invention, and FIG. 15 is a cross-sectional view illustrating
an example of a state in which an accommodation part is formed
in the pouch sheet through the accommodation part formation
20 process in the pouch forming method according to the third
embodiment of the present invention;
[0042] Referring to FIGS. 12 to 15, a pouch forming method for
forming an accommodation part lib accommodating an electrode
assembly in a pouch sheet 11 according to a first embodiment
25 of the present invention comprises a seating process of seating
15
the pouch sheet 11 on a lower die 110 in which a forming groove
111 is formed, a pouch supporting process of supporting the
pouch sheet 11 on the lower die 110 through a stripper 221, a
vacuum elongation process of elongating a portion of the pouch
5 sheet 11, in which the accommodation part lib is formed, through
vacuum, an accommodation part formation process of pressing the
portion of the pouch sheet, which is elongated through the
vacuum, by using a punch 251 to form the accommodation part lib,
and a control process of controlling vertical movement of the
10 stripper 221.
(0043] The pouch forming method according to the third
embodiment of the present invention is different from the pouch
forming method according to the foregoing first embodiment of
the present invention and the pouch forming method according
15 to the foregoing second embodiment of the present invention
in that the control process is further performed. Thus,
contents of this embodiment, which are duplicated with those
according to the forgoing embodiment, will be omitted or briefly
described, and also, differences therebetween will be mainly
20 described.
[0044] In more detail, referring to FIGS . land 13, in the pouch
supporting process of the pouch forming method according to the
third embodiment of the present invention, an outer portion lie
of the accommodation part lib in the pouch sheet 11 may be pressed
2,5 through the stripper 221 disposed above the pouch sheet 11 so
16
as to be supported on the lower die 110. Here, in the pouch
supporting process, the outer portion lie of the pouch sheet
11 may be pressed-through the stripper 221 so that the outer
portion lie of pouch sheet 11 is supported to be fixed.
5 Thereafter, when pressing force of the stripper 221 may be
adjusted through the control process to allow the punch 251 to
press the pouch sheet 11, the position of the outer portion lie
of the pouch sheet 11 may move.
[0045] In the vacuum elongation process, a lower portion of
10 the pouch sheet 11, in which the accommodation part lib is formed,
may be elongated through vacuum. Also, in the vacuum elongation
process, a space of the forming groove 111 may be vacuumized
through vacuum passages 112 and 113 connected to the forming
groove 111 in the lower die 110 to elongate a portion of the
15 pouch sheet 11, which faces the forming groove 111.
[0046] Referring to FIGS. 14 and 15, in the accommodation part
formation process, the portion of the pouch sheet 11, which is
elongated through the vacuum, may be pressed by a punch 251
disposed above the pouch sheet 11 in a direction, in which the
20 forming groove 111 is formed, to form the accommodation part
lib.
[0047] In the control process, a stripper moving part 222 for
allow the stripper 221 to vertically move may be controlled
through a control unit (not shown).
25 Also, in the control process, when the punch 251 is
7
inserted into the forming groove 111 of the lower die 110 to
press the pouch sheet 11, the stripper moving part 222 may ascend
to reduce the pressing force of the stripper 221 for pressing
the pouch sheet.
5 [0049] Furthermore, in the control process, the stripper
moving part 222 and the punch moving part 252 allowing the punch
251 to vertically move may be controlled, and thus, the stripper
221 may gradually ascend, and also, a descending speed of the
punch 251 may be gradually reduced.
10 [0050] FIG. 16 is a graph illustrating a relationship between
the pressing force and the forming depth of the stripper in the
pouch forming method according to the third embodiment of the
present invention, and FIG. 17 is a graph illustrating a
relationship between the descending speed and the forming depth
15 of the punch in the pouch forming method according to the third
embodiment of the present invention.
[0051] As shown in the graph of FIG. 16, in the control process,
the pressing force of the stripper 221 and a depth at which the
punch 251 is inserted into the forming groove 111 are inversely
20 proportional to each other. That is, as a depth of the punch
251 inserted into the forming groove 111 increases, the pressing
force of the stripper 221 may gradually decrease to expand an
elongation area of the pouch sheet 11. As a result, a local
elongation of the pouch may increase to prevent the cracks from
25 occurring. (see FIGS. 13 and 14)
18
[0052] Also, as illustrated m FIG. 17, in the control process,
the descending speed of the punch 251 and the depth of the punch
251 inserted into the forming groove 111 are inversely
proportional to each other. That is, as the depth of the punch
251 inserted into the forming groove 111 increases, the
descending speed, i.e. , the pressing force of the punch 251 may
gradually decrease to expand an elongation area of the pouch
sheet 11. As a result, a local elongation of the pouch sheet
11 may increase to prevent the cracks from occurring. (see 13
and 14)
[0053] Thus, referring to FIGS. 14 and 15, in the pouch forming
method according to the third embodiment of the present
invention, when the pouch sheet 11 is formedf the elongation
may gradually increase to form the accommodation part lib
accommodating the electrode assembly in the pouch sheet 11
without the occurrence of the cracks, thereby manufacturing the
pouch having the high quality. Here, referring to FIG. 13, the
forming portion lid of the pouch sheet 11, in which the
accommodation part lib is formed, may be elongated through the
vacuum and then pressed by using the punch 151 to form the pouch
sheet 11, the occurrence of the cracks in the forming portion
may be more effectively prevented. (see FIG. 1)
[0054] Hereinafter, a pouch forming method according to a
fourth embodiment of the present invention will be described.
Referring to FIGS. 1, 2, and 4, a pouch forming device
19
100 according to the fourth embodiment of the present invention
comprises a lower die 110 which is disposed below a pouch sheet
11 and in which a forming groove 11 is formed in an upper portion
thereof, a punch unit 150 comprising a punch 151 that presses
5 the pouch sheet 11 to form an accommodation part lib having a
shape corresponding to the forming groove 111 in the pouch sheet
11, and a vacuum unit 130 applying vacuum to the pouch sheet
11 to elongate a forming portion lid of the pouch sheet 11. Also,
the pouch forming device 100 according to the fourth embodiment
10 of the present invention may further comprise a stripper unit
120 supporting the pouch sheet 11 on the lower die 110.
[0056] The pouch forming device 100 according to the fourth
embodiment of the present invention relates to a device for
forming the pouch sheet 11, which is applied to the pouch forming
15 method according to the foregoing first embodiment of the
present invention and the pouch forming method according to the
foregoing second embodiment of the present invention. Thus,
in this embodiment, contents duplicated with those according
to the foregoing embodiments will be briefly described, and
20 differences therebetween will be mainly described.
[0057] In more detail, in the pouch forming device 100
according to the fourth embodiment of the present invention,
the accommodation part lib accommodating the electrode assembly
12 may be formed in the pouch sheet 11.
25 Here, the electrode assembly 12 may be a chargeable and
20
dischargeable power generation element and have a structure in
which an electrode 12c and a separator 12d are combined and
alternately -stacked. The electrode assembly 12 may be
accommodated in the pouch sheet 11 to constitute a secondary
5 battery 10. Also, in the secondary battery 10, an electrode
lead 13 connected to the electrode 12c of the electrode assembly
12 so as to be electrically connected to an external device may
be further provided.
[0059] The electrode 12c may comprise a positive electrode 12a
10 and a negative electrode 12b. Also, the separator 12d may
separate the positive electrode 12a from the negative electrode
12b to electrically insulate the positive electrode 12a from
the negative electrode 12b.
[0060] The positive electrode 12a may comprise a positive
15 electrode collector (not shown) and a positive electrode active
material (not shown) applied to the positive electrode
collector, and the negative electrode 12b may comprise a
negative electrode collector (not shown) and a negative
electrode active material (not shown) applied to the negative
20 electrode collector.
[0061] For example, the positive electrode collector may be
provided as foil made of an aluminum (Al) material.
[0062] The positive electrode active material may comprise,
for example, lithium manganese oxide, lithium cobalt oxide,
25 lithium nickel oxide, lithium iron phosphate, or a compound
21
containing at least one of these and mixtures thereof.
[0063] For example, the negative electrode collector may be
provided as foil made of a copper (Cu) or nickel (Ni) material.
[0064] The negative electrode active material may comprise
5 synthetic graphite, lithium a metal, a lithium alloy, carbon,
petroleum coke, activated carbon, graphite, a silicon compound,
a tin compound, a titanium compound, or an alloy thereof.
[0065] The separator 12d is made of an insulation material is
alternatively stacked with the positive electrode 12a and the
10 negative electrode 12b. Here, the separator 12dmay be disposed
between the positive electrode 12a and the negative electrode
12b and also disposed on an outer surface of each of the positive
electrode 12a and the negative electrode 12b. Also, the
separator 12d may be made of, for example, a polyolefin-based
15 resin film such as polyethylene or polypropylene having
micropores.
[0066] The lower die 110 may be disposed below the pouch sheet
11, and a forming groove 111 may be formed in an upper portion
of the lower side 110.
20 [0067] Also, vacuum passages 112 and 113 serving as passage
through which the forming groove 111 and the vacuum unit 130
are connected to each other may be formed in the lower die 110.
[0068] Suction holes 112a and 113a of the vacuum passages 112
and 113 may be connected to the forming groove 111 and disposed
25 in a lov/er portion of a side surface of the forming groove 111.
22
Thus, a forming portion of a corner of a body 11a, at which
deformation of the pouch sheet 11 largely occurs may be
effectively elongated. That is, the suction holes 112a and 113a
of the vacuum passages 112 and 113 may be formed in the lower
5 portion of the side surface of the forming groove 111, which
faces a portion at which the corner is formed on the body 11a
of the pouch sheet 11. Thus, when the corner of the body 11a
of the pouch sheet 11 is formed, an adjacent portion may be
sufficient elongated to deeply form the accommodation part lib
10 without an occurrence of cracks in the corner.
[0069] Also, the suction holes 112a and 113a of the vacuum
passages 112 and 113 may be provided in plurality along the lower
portion of the side surface of the forming groove 111.
[0070] Each of the vacuum passages 112 and 113 formed in the
15 lower die 110 may have one side connected to the forming groove
111 and the other side connected to the vacuum unit 130. Here,
each of the circular suction holes 112a and 113a may be formed
in the one side of each of the vacuum passages 112 and 113, and
each of circular connection holes 112b and 113b may be formed
20 in the other side of each of the vacuum passages 112 and 113.
Here, each of the vacuum passages 112 and 113 may have a shape
that gradually decreases in diameter toward each of the suction
holes 112a and 113a. That is, each of the vacuum passages 112
and 113 may form a circular passage and have a shape that
25 gradually decreases in diameter from the other side to one side
23
thereof. Thus, vacuum suction force in the vicinity of the
suction holes 112a and 113a of the vacuum passages 112 and 113
may increase, and thus, the elongation of the pouch sheet 11
may increase.
5 [0071] A stripper 121 may be disposed above the pouch sheet
11 to press an outer portion lie of the accommodation part 11
in the pouch sheet 11 so that the pouch sheet 11 is fixed to
the lower die 110. Here, a stripper unit 120 comprising the
stripper 121 and a stripper moving part allowing the stripper
10 121 to move may be provided.
[0072] A lower end of the stripper 121 may press the pouch sheet
II to allow the outer portion lie of the pouch sheet 11 to be
engaged with the lower die 110, thereby preventing the pouch
sheet 11 from moving when the portion of the pouch sheet 11,
15 in which the accommodation part lib is formed, is pressed
through the punch 151.
[0073] The punch 151 may be disposed above the pouch sheet 11
to press the pouch sheet 11 in a direction of the forming groove
III of the'lower die 110, thereby forming the accommodation part
20 lib in a shape corresponding to the forming groove 111 in the
pouch sheet 11. Here, a punch unit 150 comprising the punch
151 and the punch moving part allowing the punch 151 to move
may be provided.
[0074] An end 151a of the punch 151 may be disposed at a position
25 facing the forming groove 111 of the lower die 110. The end
24
151a of the punch 151 may be inserted into the forming groove
111 of the lower die 110 to press the pouch sheet 11, thereby
forming the accommodation part lib.
[0075] Also, the end 151a of the punch 151 may have a width
5 less than that of the forming groove 111 of the lower die 110.
For example, a portion of the punch 151, which is inserted into
the forming groove 111 of the lower die 110 and an inner surface
of the forming groove 111 of the lower die 110 may be spaced
a thickness of the pouch sheet 11 from each other.
10 [0076] The vacuum unit 130 may be connected to the forming
groove 111 of the lower die 110 to apply vacuum to the pouch
sheet 11 seated on a top surface of the lower die 110, thereby
elongating the forming portion lid of the pouch sheet 11.
|0077] Also, the vacuum unit 130 may comprise a vacuum pump
15 131. The vacuum unit 130 may further comprise a vacuum tube
132 which connects the vacuum pump 131 to the vacuum passages
112 and 113 of the lower die 110. Here, a space of the forming
groove 111 of the lower die 110 may be connected to the vacuum
pump 131 through the vacuum passages 112 and 131 and the vacuum
20 tube 132 so that the space of the forming groove 111 of the lower
die 110 is vacuumized through the vacuum pump 131. Thus, a
portion of the pouch sheet 111, which covers the space of the
forming groove 111 of the lower die 110, may be elongated. As
a result, the occurrence of the cracks in the elongated pouch
25 sheet 11 may be prevented when being pressed by the punch 151.
25
[0078] Hereinafter, a pouch forming method according to a fifth
embodiment of the present invention will be described.
[0079] Referring to FIGS. 1, and 2 and 12 to 15, a pouch forming
device 200 according to the fifth embodiment of the present
5 invention comprises a lower die 110 which is disposed below a
pouch sheet 11 and in which a forming groove 11 is formed in
an upper portion thereof, a punch unit 250 comprising a punch
251 that presses the pouch sheet 11 to form an accommodation
part lib having a shape corresponding to the forming groove 111
10 in the pouch sheet 11, a vacuum unit 130 applying vacuum to the
pouch sheet 11 to elongate a forming portion lid of the pouch
sheet 11, and a stripper unit 220 comprising a stripper 221
supporting the pouch sheet 11 on the lower die 110.
[0080] The pouch forming device 200 according to the fifth
15 embodiment of the present invention relates to a device for
forming the pouch sheet 11, which is applied to the pouch forming
method according to the foregoing third embodiment of the
present invention. Thus, in this embodiment, contents
duplicated with those according to the foregoing embodiments
20 will be omitted or briefly described, and differences
therebetween will be mainly described.
[0081] In more detail, in the pouch forming device 200
according to the fifth embodiment of the present invention, the
accommodation part lib accommodating the electrode assembly 12
25 may be formed in the pouch sheet 11.
26
[0082] The lower die 110 may be disposed below the pouch sheet
11, and a forming groove 111 may be formed in an upper portion
of the lower side 110.
[0083] Also, vacuum passages 112 and 113 serving as passage
5 through which the forming groove 111 and the vacuum unit 130
are connected to each other may be formed in the lower die 110.
[0084] Suction holes 112a and 113a of the vacuum passages 112
and 113 may be connected to the forming groove 111 and disposed
in a lower portion of a side surface of the forming groove 111.
10 [0085] Each of the vacuum passages 112 and 113 formed in the
lower die 110 may have one side connected to the forming groove
111 and the other side connected to the vacuum unit 130.
[0086] The stripper unit 220 may comprises the stripper 221
supporting the pouch sheet 11 on the lower die 110 and a stripper
15 moving part 222 allowing the stripper 221 to vertically move.
[0087] The stripper 221 may be disposed above the pouch sheet
11 to press the outer portion lie of the accommodation part 11
in the pouch sheet 11, thereby supporting the pouch sheet 11
on the lower die 110.
20 [0088] For example, the stripper 221 may have a bottom surface
having a size corresponding to that of the top surface of the
lower die 110. Here, a through-hole 221a vertically passing
through the stripper 221 and having a size corresponding to that
of the forming groove 111 of the lower die 110 may be formed
25 in the stripper 221,
27
[0089] The stripper moving part 222 may allow the stripper 221
to vertically move and allow the punch 251 to descend, thereby
supporting the pouch sheet 11. For example, the stripper moving
part 222 may comprise a pneumatic or hydraulic actuator. Here,
5 the stripper moving part 222 may be provided with a moving rod
222a for allowing the stripper 221 to move at a lower portion
thereof.
[0090] The punch unit 250 may comprise a punch 251 forming the
accommodation part 111b in the pouch sheet 11 in a shape
10 corresponding to the forming groove 111 of the lower die 110
and a punch moving part 252 allowing the punch 251 to vertically
move. Here, the punch unit 250 may further comprise a punch
plate 253 connecting the punch 251 to the punch moving part 252 .
[0091] The punch 251 may be disposed above the pouch sheet 11
15 to press the pouch sheet 11 in the direction of the forming groove
111 of the lower die 110, thereby forming the accommodation part
lib in the pouch sheet 11 in a shape corresponding to the forming
groove 111 of the lower die 110. Here, an end 251a of the punch
251 may be disposed at a position facing the forming groove 111
20 of the lower die 110. The end 251a of the punch 251 may be
inserted into the forming groove 111 of the lower die 110 to
press the pouch sheet 11, thereby forming the accommodation part
lib.
[0O£"2] The punch moving part 252 may allow the punch 251 to
25 vertically move, for example, descend, thereby pressing the
28
pouch sheet 11. For example, the punch moving part 252 may
comprise a pneumatic or hydraulic actuator.
[0093] The punch plate 253 may be provided as a plate that is
disposed on an upper end of the punch 251 to further extend in
5 a horizontal direction. Here, the punch moving part 252 may
allow the punch plate 253 to vertically move so that the punch
moves. For example, the punch 251 and the punch plate 253 may
be integrally formed.
[0094] The vacuum unit 130 may be connected to the forming
10 groove 111 of the lower die 110 to apply vacuum to the pouch
sheet 11 seated on a top surface of the lower die 110, thereby
elongating the forming portion lid of the pouch sheet 11.
[0095] A control unit (not shown) may adjust pressing force
of the stripper 221, which presses the pouch sheet 11.
15 [0096] Also, the control unit may control the stripper moving
part 222 to allow the stripper 221 to ascend when the punch 251
is inserted into the forming groove 111 to press the pouch sheet
11 so that the pressing force of the stripper 221, which presses
the pouch sheet 11, is reduced.
20 [0097] The control unit may control the punch moving part 252
and the stripper moving part 222. Here, the control unit may
electrically connect the punch moving part 252 to the stripper
moving part 222.
The control unit may control the punch moving part 252
25 so that the stripper 221 gradually ascends and simultaneously
29
control the stripper moving part 222 so that a descending speed
of the punch 251 gradually decreases.
[0099] [Experimental Example 1]
[00100] FIG. 18 is a table showing results obtained through
5 Experimental Example 1 in a pouch forming device according to
a fourth embodiment of the present invention.
[00101] Comparative Example 1
[00102] In Comparative Example 1, an accommodation part
accommodating an electrode assembly is formed in a pouch sheet
10 by using a pouch forming device comprising a lower die, a
stripper, and a punch. That is, the pouch sheet is formed by
using the constituents except for the vacuum unit in the pouch
forming device according to the fourth embodiment of the present
invention.
15 [00103] Manufacturing Example 1
[00104] In Manufacturing Example 1, an accommodation part
accommodating an electrode assembly is formed in a pouch sheet
by using a pouch forming device comprising a lower die, a punch,
a stripper, and a vacuum unit. That is, the pouch sheet is
20 formed by using the constituents of the pouch forming device
according to the fourth embodiment of the present invention.
[00105] Here, in Comparative Example 1 and Manufacturing
Example 1, the same pouch sheet is used, and the pouch sheet
is formed under the same environment. Here, the same
25 environment has following conditions: a pressure of the
30
stripper: 4 kg/cm2, an initial descending speed of the punch:
30 ran/s, and a surface roughness of the punch: 0.1 s.
[00106] Elongation
[00107] As results obtained by measuring whether the pouch
5 sheet formed through Comparative Example 1 and Manufacturing
Example 1 is defective, a result table as illustrated in FIG.
18 may be obtained.
[00108] Referring to the result table of FIG. 18, in
Comparative Example 1, it is seen that wrinkles and cracks occur
10 in the pouch sheet from a point at which the punch descends by
8 mm from the uppermost end of the forming groove of the lower
die. Also, in Manufacturing Example^ it is seen that wrinkles
and cracks occur in the pouch sheet from a point at which the
punch descends by 10 mm from the uppermost end of the forming
15 groove of the lower die.
[00109] In summary, in Manufacturing Example 1, the wrinkles
and the cracks occur after further descending by 2 mm when
compared to Comparative Example 1. As the results of the above
experiments, in Manufacturing Example 1, it is confirmed that
20 the elongation increases when compared to Comparative Example
1.
[00110] [Experimental Example 2]
[00111] FIG. 19 is a table showing results obtained through
Experimental Example 2 in a pouch forming device according to
25 a fifth embodiment of the present invention.
31
[00112] Comparative Example 2
[00113] In Comparative Example 2, an accommodation part
accommodating an electrode assembly is formed in a pouch sheet
by using a pouch forming device comprising a lower die, a
5 stripper, and a punch. That is, the pouch sheet is formed by
using the constituents except for the vacuum unit and the
control unit in the pouch forming device according to the fifth
embodiment of the present invention.
[00114] Manufacturing Example 2
10 [00115] In Manufacturing Example 2, an electrode assembly
accommodation part is formed In a pouch sheet by using a pouch
forming device comprising a lower die, a stripper, a punch, a
vacuum unit, and a control unit. That is, the pouch sheet is
formed by using the constituents of the pouch forming device
15 according to the fifth embodiment of the present invention.
[00116] Here, in Comparative Example 2 and Manufacturing
Example 2, the same pouch sheet is used, and the pouch sheet
is formed under the same environment. Here, the same
environment has following conditions: a pressure of the
20 stripper member: 4 kg/cilf, an initial descending speed of the
punch: 30mm/s, a pressure inverse proportion control rate : 95%,
and a surface roughness of the punch: 0.1 s.
[00117] Elongation
I/«HJ,I«~] AS results obtained by measuring whether the pouch
25 sheet formed through Comparative Example 2 and Manufacturing
32
Example 2 is defective, a result table as illustrated in FIG.
19 may be obtained.
[00119] Referring to the result table of FIG. 19, in
Comparative Example 2, it is seen that wrinkles and cracks occur
5 in the pouch sheet from a point at which the punch descends by
8 mm from the uppermost end of the forming groove of the lower
die. Also, in Manufacturing Example 2, it is seen that wrinkles
and cracks occur in the pouch sheet from a point at which the
punch descends by 13 mm from the uppermost end of the forming
10 groove of the lower die.
[00120] In summary, in Manufacturing Example 2, the wrinkles
and the cracks occur after further descending by 5 mm when
compared to Comparative Example 2. As the results of the above
experiments, in Manufacturing Example 2, it is confirmed that
15 the elongation increases when compared to Comparative Example
2.
[00121] According to the present invention, when the punch
presses the pouch sheet to form the accommodation part
accommodating the electrode assembly, the vacuum may be applied
20 to the portion, at which the accommodation part is formed, of
the pouch sheet to elongate the portion, thereby preventing the
cracks from occurring.
[00122] Also, according to the present invention, when the
pouch is formed, the pressing force of the stripper supporting
25 the pouch sheet may gradually decrease, or the descending speed
33
of the punch may gradually decrease to gradually increase in
elongation when the pouch is formed, thereby stably forming the
pouch. Particularly, when the pouch is formed, the local
portion, i.e., the edge or vertex portion of the electrode
5 assembly accommodation part formed in the pouch may be
effectively prevented from being cracked.
[00123] While the present invention has been particularly
shown and described with reference to exemplary embodiments
thereof, it is to be understood that the scope of the present
10 invention is not limited to the pouch forming method and the
pouch forming device according to the present invention. It
will be understood by those of ordinary skill in the art that
various changes in form and details may be made therein without
departing from the spirit and scope of the invention.
15 [00124] Furthermore, the scope of protection of the present
invention will be clarified by the appended claims.

What: Is Claimed Is:
1. A pouch forming method for forming an accommodation part
accommodating an electrode assembly in a pouch sheet, the pouch
forming method comprising:
5 a seating process of seating the pouch sheet on a top
surface of a lower die in which a forming groove is formed in
an upper portion thereof;
a vacuum elongation process of elongating a lower portion
of the pouch sheet, in which the accommodation part is formed,
10 through vacuum; and
an accommodation part formation process of pressing the
portion of the pouch sheet, which is elongated through the
vacuum, by using a punch disposed above the pouch sheet in a
direction in which the forming groove is formed to form the
15 accommodation part.
2 . The pouch forming method of claim 1, wherein, in the vacuum
elongation process, a space of the forming groove is vacuumized
through a vacuum passage connected to the forming groove in the
20 lower die to elongate a portion of the pouch sheet, which faces
the forming groove.
3 . The pouch forming method of claim 2 , wherein, in the vacuum
elongation process, the space of the forming groove is
25 vacuumized through a plurality of suction holes the vacuum
35
passage, which are formed along a lower portion of a side surface
of the forming groove, to elongate the forming portion.
4. The pouch forming method of claim 1, wherein the vacuum
5 elongation process is performed before the accommodation part
formation process.
5. The pouch forming method of claim 1, wherein the vacuum
elongation process and the accommodation part formation process
10 are performed at the same time.
6. The pouch forming method of claim 1, further comprising
a pouch supporting process of pressing an outer portion of the
accommodation part in the pouch sheet through a stripper
15 disposed on an upper portion of the pouch sheet to support the
pouch sheet on the lower die.
7. The pouch forming method of claim 6, further comprising
a control process of controlling a stripper moving part, which
20 allows the stripper to vertically move, through a control unit,
wherein, in the control process, when the punch is
inserted into the forming groove of the lower die to press the
pouch sheet, the stripper allows the stripper moving part to
ascend so as to decrease in pressing force that presses the pouch
25 sheet,
36
8. The pouch forming method of claim 7, wherein, in the
control process-, the stripper moving part and a punch moving
part, which allows the punch to vertically move, are controlled
5 so that the stripper gradually ascends, and simultaneously, the
punch gradually decreases in descending speed.
9. A pouch forming device for forming an accommodation part
accommodating an electrode assembly in a pouch sheet, the pouch
10 forming device comprising:
a lower die which is disposed on a lower portion of the
pouch sheet and in which a forming groove is formed in an upper
portion thereof;
a punch unit disposed above the pouch sheet and comprising
15 a punch pressing the pouch sheet in a direction of the forming
groove of the lower die to form the accommodation part in the
pouch sheet in a shape corresponding to the forming groove; and
a vacuum unit connected to the forming groove of the lower
side to apply vacuum to the pouch sheet seated on a top surface
20 of the lower die so as to elongate the forming portion of the
pouch sheet.
10. The pouch forming device of claim 9, wherein a vacuum
passage serving as a passage connecting the forming groove to
25 the vacuum unit is further formed in the lower die.
37
11. The pouch forming device of claim 10, wherein a suction
hole of the' vacuum passage connected to the forming groove is
provided in a lower portion of a side surface of the forming
5 groove.
12. The pouch forming device of claim 11, wherein the suction
hole of the vacuum passage is provided in plurality along the
lower portion of the side surface of the forming groove.
10
13. The pouch forming device of claim 11, wherein the vacuum
passage has a shape that gradually decreases in diameter toward
the suction hole.
15 14. The pouch forming device of claim 9, wherein the vacuum
unit comprises a vacuum pump.
15. The pouch forming device of claim 10, wherein an end of
the punch is disposed at a position facing the forming groove
20 of the lower die, and
the end of the punch is inserted into the forming groove
of the lower die to press the pouch sheet so as to form the
accommodation part.
25 16. The pouch forming device of claim 9, further comprising
38
a stripper unit comprising: a stripper disposed above the pouch
sheet and pressing an outer portion of the accommodation part
in the pouch sheet to support the pouch sheet on the lower die;
and a stripper moving part allowing the stripper to vertically
5 move.
17. The pouch forming device of claim 16, further comprising
a control unit adjusting pressing force for pressing the pouch
sheet through the stripper,
10 wherein, when the punch is inserted into the forming
groove of the lower die to press the pouch sheet, the control
unit controls the stripper moving"part to allow the stripper
to ascend so that the stripper presses the pouch sheet.
15 18. The pouch forming device of claim 17, wherein the punch
unit further comprises a punch moving part allowing the punch
to vertically move, wherein the punch moving part allows the
punch to descend so as to press the pouch sheet, and
the control unit controls the punch moving part and the
20 stripper moving part so that the stripper gradually ascends,
and simultaneously, the punch gradually decreases in descending
speed.