TECHNICAL FIELD
[0002] The present invention relates to a method for
manufacturing a secondary battery and a secondary battery.
BACKGROUND ART
[0003] Secondary batteries are rechargeable unlike primarily
15 batteries, and also, the possibility of compact size and high
capacity is high. Thus, recently, many studies on secondary
batteries are being carried out. As technology development
and demands for mobile devices increase, the demands for
secondary batteries as energy sources are rapidly increasing.
20 [0004] Rechargeable batteries are classified into coin type
batteries, cylindrical type batteries, prismatic type
batteries, and pouch type batteries according to a shape of a
battery case. In such a secondary battery, an electrode
assembly mounted in a battery case is a chargeable and
25 dischargeable power generating device having a structure in
3
which an electrode and a separator are stacked.
[0005] Also, 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
5 negative electrode, each of which is provided as the form of
a sheet coated with an active material, and then, the positive
electrode, the 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
10 are sequentially stacked, and a stack/folding type electrode
assembly in which stacked type unit cells are wound together
with a separation 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
15 battery case provided as an aluminum lamination sheet is
attracting much attention due to its low manufacturing cost,
light weight, easy shape deformation, and the like, and thus,
its usage is gradually increasing.
[0007] In the case of the L-shaped pouch-type battery, there
20 have been cases in which pouch cracks occur in an L-shape
section during pouch forming, and a criterion of a residual
amount of aluminum (AL) is not satisfied.
[0008] [Prior Art Document] (Patent Document) Korean Patent
Publication No. 10-2012-0067550
25 DISCLOSURE OF THE INVENTION
4
TECHNICAL PROBLEM
[0009] One aspect of the present invention is to provide a
method for manufacturing a secondary battery, which is capable
of preventing cracks occurring in a bending section when
5 forming from occurring and capable of improving a residual
amount of aluminum.
TECHNICAL SOLUTION
[0010] A method for manufacturing a secondary battery
according to an embodiment of the present invention comprises:
10 a cutting process of slit-cutting a portion of a pouch in an
arc shape to form a cutting part; a forming process of forming
an accommodating part in a bent shape to accommodate an
electrode assembly having a bent shape in the pouch after the
cutting process; and an accommodating process of accommodating
15 the electrode assembly in the accommodating part of the pouch
after the forming process, wherein, in the cutting process,
the cutting part is formed at a portion of the pouch, which is
adjacent to an inner corner portion in the accommodating part
having the bent shape.
20 [0011] A secondary battery according to an embodiment of the
present invention may be a secondary battery manufactured
through the method for manufacturing the secondary battery
according the foregoing embodiment of the present invention.
ADVANTAGEOUS EFFECTS
25 [0012] According to the present invention, when forming the
5
pouch of the pouch-type secondary battery having the bent shape,
the arc slit cut may be performed in the section adjacent to
the accommodating part having the bent shape in the pouch to
relieve the stress generated in the bent-shaped section and
5 improve the residual amount of aluminum.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a plan view illustrating a cutting process
in a method for manufacturing a secondary battery according to
an embodiment of the present invention.
10 [0014] FIG. 2 is a plan view illustrating a forming process
in the method for manufacturing the secondary battery according
to an embodiment of the present invention.
[0015] FIG. 3 is a plan view illustrating an accommodating
process in a method for manufacturing a secondary battery
15 according to an embodiment of the present invention.
[0016] FIG. 4 is a perspective view illustrating a sealing
process in the method for manufacturing the secondary battery
according to an embodiment of the present invention.
[0017] FIG. 5 is a plan view illustrating a first example of
20 a cutting part formed on a pouch in the method for
manufacturing the secondary battery according to an embodiment
of the present invention.
[0018] FIG. 6 is a plan view illustrating a second example of
the cutting part formed on the pouch in the method for
25 manufacturing the secondary battery according to an embodiment
6
of the present invention.
[0019] FIG. 7 is a plan view illustrating a third example of
the cutting part formed on the pouch in the method for
manufacturing the secondary battery according to an embodiment
5 of the present invention.
[0020] FIG. 8 is a plan view illustrating reference symbols
of portions of the pouch that has undergone the cutting process
and the forming process in the method for manufacturing the
secondary battery according to an embodiment of the present
10 invention.
[0021] FIG. 9 is an image illustrating a ratio of thinning at
a portion P6 of the pouch illustrated in FIG. 8.
MODE FOR CARRYING OUT THE INVENTION
[0022] The objectives, specific advantages, and novel
15 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,
20 even if they are illustrated in other drawings. Also, the
present invention may be embodied in 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
25 obscure the gist of the present invention will be omitted.
7
[0023]
[0024] Method for manufacturing secondary battery according
to embodiment
[0025]
5 [0026] FIG. 1 is a plan view illustrating a cutting process
in a method for manufacturing a secondary battery according to
an embodiment of the present invention, FIG. 2 is a plan view
illustrating a forming process in the method for manufacturing
the secondary battery according to an embodiment of the present
10 invention, FIG. 3 is a plan view illustrating an accommodating
process in a method for manufacturing a secondary battery
according to an embodiment of the present invention, and FIG.
4 is a perspective view illustrating a sealing process in the
method for manufacturing the secondary battery according to an
15 embodiment of the present invention.
[0027] Referring to FIGS. 1 to 4, a method for manufacturing
a secondary battery according to an embodiment of the present
invention may comprise a forming process of forming an
accommodating part 112 in a pouch 110, a cutting process of
20 cutting a portion of the pouch 110 adjacent to an inner corner
portion in the accommodating part 112, and an accommodating
process of accommodating an electrode assembly 120 into the
pouch 110 after the forming process to manufacture a secondary
battery 100. In addition, the method for manufacturing the
25 secondary battery according to an embodiment of the present
8
invention may further comprise a sealing process for sealing
the pouch 110.
[0028]
[0029] Hereinafter, the method for manufacturing the
5 secondary battery according to an embodiment of the present
invention will be described in more detail.
[0030] Referring to FIGS. 1 and 2, in the cutting process, a
portion of the pouch 110 is slit-cut in an arc shape to form
a cutting part 111.
10 [0031] Also, in the cutting process, the cutting part 111 may
be formed in consideration of a position at which the
accommodating part 112 that accommodates the electrode
assembly 120 will be formed in a subsequent process. That is,
in the cutting process, the cutting part 111 may be formed at
15 the portion of the pouch 110 adjacent to the inner corner
portion 113 in the bent accommodating part 112.
[0032] In addition, in the cutting process, the cutting part
111 may be formed in an arc shape that is convex toward the
inner corner portion 113 of the pouch 110 accommodating part
20 112.
[0033] In addition, in the cutting process, the cutting part
111 may be formed as an arc-shaped cutting line in the plan
view.
[0034] FIG. 5 is a plan view illustrating a first example of
25 the cutting part formed on the pouch in the method for
9
manufacturing the secondary battery according to an embodiment
of the present invention, FIG. 6 is a plan view illustrating
a second example of the cutting part formed on the pouch in
the method for manufacturing the secondary battery according
5 to an embodiment of the present invention, and FIG. 7 is a
plan view illustrating a third example of the cutting part
formed on the pouch in the method for manufacturing the
secondary battery according to an embodiment of the present
invention.
10 [0035] Referring to FIGS. 5 to 7, in the cutting process, the
arc-shaped cutting line of the cutting part 111 may be formed
in an arc shape at an angle, for example, 60° to 285° (degrees).
Here, in the cutting process, the arc-shaped cutting line of
the cutting part 111 may be formed at an angle of 60 degrees
15 or more to effectively improve thinning of the pouch, and the
cutting line may be formed at an angle of 285 degrees or less
to prevent the portion of the pouch 110, which is cut as the
arc-shaped cutting line, from being torn or separated, thereby
realizing the thinning of the pouch.
20 [0036] Also, In the cutting process, the arc-shaped cutting
line of the cutting part 111 may be specifically formed, for
example, in an arc shape at an angle of 120 degrees to 210
degrees. Here, in the cutting process, a radius of the arc of
the cutting part 111 may be, for example, 4 mm to 12 mm.
25 [0037] More specifically, for example, referring to FIG. 5,
10
in the cutting process, the arc-shaped cutting line of the
cutting part 111 may be formed at an angle t1 of 120 degrees
as a first example, and referring to FIG. 6, the arc-shaped
cutting line of the cutting part 111 may be formed at an angle
5 t2 of 180 degrees as a second example. In addition, referring
to FIG. 7, the arc-shaped cutting line of the cutting part 111
may be formed at an angle t3 of 210 degrees as a third example.
[0038] In addition, in the cutting process, the cutting part
111 may be formed to be spaced a predetermined interval from
10 the accommodating part 112. That is, in the cutting process,
the cutting part 111 may formed to be spaced a predetermined
interval from the accommodating part 112 in consideration of
a position of the accommodating part 112 to be formed in the
subsequent forming process. In this case, in the cutting
15 process, for example, the interval b between the cutting part
111 and the accommodating part 112 may be formed to be 4 mm to
12 mm.
[0039] The pouch 110 may comprise an aluminum (Al) material.
In this case, for example, the pouch 110 may comprise an
20 aluminum layer and a resin layer.
[0040]
[0041] Referring to FIG. 2, in the forming process, the
accommodating part 112 having the bent shape may be formed in
the pouch 110 to accommodate the bent electrode assembly 120
25 after the cutting process. Here, the accommodating part 112
11
may be formed as, for example, a cup-shaped groove. In this
case, the accommodating part 112 may be formed in an upwardly
opened shape. Here, the 'bent shape' does not mean that the
electrode assembly 120 and the accommodating part 112 are bent
5 by external force, but may mean, for example, a vertically
extending shape.
[0042] Furthermore, in the forming process, the accommodating
part 112 may be formed in a shape corresponding to the
electrode assembly 120.
10 [0043] In the forming process, for example, the accommodating
part 112 may be formed by pressing the pouch 110 from the top
to the bottom through a punch.
[0044] Here, the electrode assembly 120 may be formed in a
shape bent at a right angle. In this case, the electrode
15 assembly 120 may be formed to be bent in an “L” shape.
[0045] In addition, in the forming process, the accommodating
part 112 may be formed in a shape bent at a right angle. In
this case, the forming process, the accommodating part 112 may
be formed to be bent in an “L” shape.
20 [0046] In addition, in the forming process, the inner corner
portion 113 of the pouch 110 may be formed in a shape that is
recessed in a direction of the accommodating part 112 in the
plan view. Here, the inner corner portion 113 may be formed,
for example, in a shape that is recessed in a round shape.
25 Here, as the arc-shaped cutting part 111 is formed at a
12
distance adjacent to the inner corner portion 113 in the
previous cutting process, an occurrence of excessive stress
generated when the inner corner portion 113 is formed in a
recessed shape in the forming process may be solved to
5 effectively prevent cracks from occurring.
[0047] The electrode assembly 120 is a power generating
element that is chargeable and dischargeable and forms a
structure in which electrodes and separators are combined and
alternately stacked.
10 [0048] The electrodes may comprise a positive electrode and
a negative electrode. Also, each of the separators separates
the positive electrode from the negative electrode to
electrically insulate the positive electrode from the negative
electrode.
15 [0049] The separator is alternately stacked with the positive
electrode and the negative electrode, which are made of
insulation materials.
[0050] Also, each of the separator 114 may be, for example,
a multi-layered film produced by microporous polyethylene,
20 polypropylene, or a combination thereof or a polymer film for
solid polymer electrolytes or gel-type polymer electrolytes
such as polyvinylidene fluoride, polyethylene oxide,
polyacrylonitrile, or polyvinylidene fluoride
hexafluoropropylene copolymers.
25 [0051] An electrode lead 130 may be connected to the electrode
13
assembly 120 so as to be electrically connected to the outside.
That is, the electrode lead 130 may be connected to the
electrode of the electrode assembly 120 to electrically connect
the electrode to an external terminal.
5 [0052]
[0053] Referring to FIG. 3, in the accommodating process, the
electrode assembly 120 may be accommodated in the accommodating
part 112 of the pouch 110 after the forming process.
[0054] In addition, in the accommodating process, an upper
10 portion of the accommodating part 112 in which the electrode
assembly 120 is accommodated may be covered. That is, the
other side of the pouch 110 may be folded with respect to a
folding line F of the pouch 110 to cover the accommodating
part 112 formed at one side of the pouch 110 with respect to
15 the folding line F of the pouch 110.
[0055] In addition, an inner corner of the electrode assembly
120 may be formed in a shape corresponding to the inner corner
portion 113 formed in the recessed shape in the pouch 110.
That is, an inner corner portion of the electrode assembly 120
20 may be formed in a shape corresponding to the inner corner
portion 113 formed in the recessed shape of the pouch 110.
[0056]
[0057] Referring to FIG. 4, in the sealing process, an outer
circumferential surface of the pouch 110 may be sealed to seal
25 the pouch 110. In this case, in the sealing process, heat may
14
be applied along an edge of the accommodating part 112 of the
pouch 110 to form the sealing part.
[0058] In addition, the sealing process may comprise a
removing process of cutting and removing a portion remaining
5 except for the accommodating part 112 and the sealing part.
In this case, in the removing process, the cutting part 111 of
the pouch 110 may be removed together.
[0059]
[0060] Referring to FIGS. 1 to 4, in the method for
10 manufacturing the secondary battery according to an embodiment
of the present invention, which is configured as described
above, when the pouch 110 of the pouch-type battery having the
bent shape is formed, arc slit cutting may be performed in a
section A adjacent to a portion at which the bent-shaped
15 accommodating part 112 is formed in the pouch 110 to relieve
an occurrence of stress generated in the adjacent section A of
the bent-shaped accommodating part 112, thereby preventing
cracks from occurring and improving a residual amount of
aluminum.
20 [0061]
[0062] Referring to FIG. 4, the secondary battery according
to an embodiment of the present invention may be a product
manufactured by the method for manufacturing the secondary
battery according to the embodiment of the present invention,
25 which is configured as described above.
15
[0063]
[0064]
[0065] Referring to FIG. 5, a portion of a pouch 110′ was
slit-cut in an arc shape to form a cutting part 111′ to form a
5 bent-shaped accommodating part 112. Here, the cutting part
111′ was formed in the portion of the pouch 110′ adjacent to an
inner corner portion of the bent accommodating part 112. Here,
the cutting part 111′ was formed in an arc shape having an
angle t1 of 120 degrees. The cutting part 111' was formed so
10 that a radius R of the cutting part 111' is 8 mm, and a spaced
distance b between the cutting part 111' and the accommodating
part 112 is 8 mm.
[0066]
[0067]
15 [0068] Referring to FIG. 6, the same process as in
Manufacturing Example 1 was performed except that an angle t2
of a cutting part 111'' of a pouch 110" is formed in an arc
shape having an angle of 180 degrees.
[0069]
20 [0070]
[0071] Referring to FIG. 7, the same process as in
Manufacturing Example 1 was performed except that an angle t3
of a cutting part 111''' of a pouch 110"' is formed in an arc
shape having an angle of 210 degrees.
25 [0072]
16
[0073]
[0074] The same process as in Manufacturing Example 1 was
performed except that slit cutting is performed in a pouch to
form a cutting part in a straight line shape.
5 [0075]
[0076]
[0077] FIG. 8 is a plan view illustrating reference symbols
of portions of the pouch that has undergone the cutting process
and the forming process in the method for manufacturing the
10 secondary battery according to an embodiment of the present
invention, and FIG. 9 is an image illustrating a ratio of
thinning at a portion P6 of the pouch illustrated in FIG. 8.
[0078] Here, FEA simulation was performed to measure a maximum
thinning ratio of the pouch at each portion of the pouch
15 illustrated in FIG. 8, and thus, the results were shown in
Table 1 below. Then, the thinning ratio of the pouch at an
inner corner portion P6 illustrated in FIG. 8 was measured,
and an image of FIG. 9 was shown. Here, the thinning of the
pouch at the inner corner portion P6 in Comparative Example 1,
20 Manufacturing Example 1, Manufacturing Example 2, and
Manufacturing Example 3 in the order of FIGS. 9(a), 9(b), 9(c),
and 9(d) (see FIG. 8).
[Table 1]
Round Slit
Cutting
Max, Thinning (%)
P1 P2 P3 P4 P5 P6
Comparative Example 1 0° 26.32 33.67 34.01 22.74 35.12 46.31
17
Straight
Manufacturing Example 1 120° 26.63 33.98 34.23 22.50 35.01 45.80
Manufacturing Example 2 180° 25.90 33.05 34.06 22.40 34.87 45.29
Manufacturing Example 3 210° 25.99 34.30 34.72 22.84 34.50 44.46
[0079] Referring to Table 1, it is confirmed that an effect
of thinning of the pouch in Manufacturing Examples 1 to 3, in
which the arc slit cutting is performed, is improved compared
to Comparative Example 1, in which the cutting part of the
5 pouch is formed in the straight line shape. Particularly, it
is seen that the thinning ratio of the pouch at the inner
corner portion P6 of the pouch is 46.31% in Comparative Example
1, 45.80% in Manufacturing Example 1, 45.29% in Manufacturing
Example 2, and 44.46% in Manufacturing Example 3. Here, it is
10 seen that an amount of inflow from a portion P4 part to the
portion P6 of the pouch increases, and thus, a thinning value
of the pouch decreases to improve a residual amount of AI.
That is, it is seen that an effect of the thinning of the pouch
is improved by about 3.5% in Manufacturing Examples 1 to 3
15 when compared to that of the thinning of the pouch at the inner
corner portion P6 of the pouch.
[0080] 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
20 invention is not limited thereto. 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
18
the spirit and scope of the present invention.
[0081] Furthermore, the scope of protection of the present
invention will be clarified by the appended claims.
[0082]
5 [Description of the Symbols]
[0083] 100: Secondary battery
[0084] 110: Pouch
[0085] 111, 111', 111", 111''': Cutting part
[0086] 112: Accommodating part
10 [0087] 113: Inner corner portion
[0088] 120: Electrode assembly
[0089] 130: Electrode lead
19
CLAIMS
1. A method for manufacturing a secondary battery, the
method comprising:
5 a cutting process of slit-cutting a portion of a pouch
in an arc shape to form a cutting part;
a forming process of forming an accommodating part in a
bent shape to accommodate an electrode assembly having a bent
shape in the pouch after the cutting process; and
10 an accommodating process of accommodating the electrode
assembly in the accommodating part of the pouch after the
forming process,
wherein, in the cutting process, the cutting part is
formed at a portion of the pouch, which is adjacent to an inner
15 corner portion in the accommodating part having the bent shape.
2. The method of claim 1, wherein the electrode
assembly is formed in a shape bent at a right angle, and
in the forming process, the accommodating part is formed
20 in a shape bent at a right angle.
3. The method of claim 1, wherein the electrode
assembly is formed to be bent in an “L” shape, and
in the forming process, the accommodating part is formed
25 to be bent in an “L” shape.
20
4. The method of claim 1, wherein, in the forming
process, the accommodating part is formed in a shape
corresponding to the electrode assembly.
5
5. The method of claim 1, wherein, in the cutting
process, the cutting part is formed in an arc shape that is
convex toward the inner corner portion in the accommodating
part having the bent shape in the pouch.
10
6. The method of claim 5, wherein, in the cutting
process, the cutting part is formed as an arc-shaped cutting
line in a plan view.
15 7. The method of claim 6, wherein, in the cutting
process, the arc-shaped cutting line of the cutting part is
formed in an arc shape having an angle of 60 degrees to 285
degrees.
20 8. The method of claim 7, wherein, in the cutting
process, the arc-shaped cutting line of the cutting part is
formed in an arc shape having an angle of 120 degrees to 210
degrees.
25 9. The method of claim 6, wherein, in the cutting
21
process, the cutting part is formed to be spaced a
predetermined interval from the accommodating part.
10. The method of claim 1, wherein, in the forming
5 process, the inner corner portion of the pouch is formed in a
shape that is recessed in a direction of the accommodating
part in a plan view.
11. A secondary battery manufactured by the method for
10 manufacturing the secondary battery of claims 1 to 10.