【Technical Field】
[1] This application claims the benefit of priority
to Korean Patent Application No. 2020-0136880 filed on
October 21, 2020, the disclosure of which is incorporated
herein by reference in its entirety.
[2] The present invention relates to a pouch-shaped
battery case shaping apparatus using an electromagnetic
field and a pouch-shaped battery case shaping method
using the same. More particularly, the present invention
relates to a pouch-shaped battery case shaping apparatus
using an electromagnetic field including a punch
configured to shape a laminate sheet that is used as a
pouch-shaped battery case into a rectangular
parallelepiped shape, wherein an electromagnetic field is
generated in the laminate sheet in order to minimize
damage to the surface of the laminate sheet, and a pouchshaped
battery case shaping method using the same.
【Background Art】
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[3] Demand for a secondary battery as an energy
source for mobile devices and electric vehicles has
abruptly increased. In particular, demand for a lithium
secondary battery, which has high energy density and
discharge voltage, is very high.
[4] Based on the shape thereof, the lithium secondary
battery may be classified as a cylindrical battery, a
prismatic battery, or a pouch-shaped battery. The pouchshaped
battery has advantages in that the pouch-shaped
battery can be stacked with high degree of integration,
has high energy density per unit weight, is inexpensive,
and is easily deformable. The pouch-shaped battery uses
a laminate sheet as a battery case, and is configured to
have a structure in which an electrode assembly is
received in a receiving portion formed in the laminate
sheet together with an electrolytic solution.
[5] The receiving portion of the pouch-shaped battery
is formed by pressing a ductile laminate sheet through
deep drawing using a punch in the state in which the
sheet is fixed. During pressing using the punch, defects,
such as pin-holes or cracks, are formed on the outer
surface of the laminate sheet due to the force of
friction between the punch and the laminate sheet as the
result of contact therebetween and limited ductility of
the laminate sheet. As deep drawing progresses,
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frictional force at the edge distal end of the punch is
exponentially increased, whereby defects are frequently
formed in the laminate sheet that contacts the edge
distal end of the punch. For this reason, it is not
possible to greatly reduce the thickness of the laminate
sheet, which is used as a battery case, which acts as a
limitation in increasing the capacity of the battery per
unit volume.
[6] In order to solve the above problem, various
attempts, including disposing a heater in a pressing
punch, including an electromagnetic force generation unit,
or providing a punch head made of a low coefficient of
friction material, have been made.
[7] Patent Document 1 relates to a shaping method for
securing a pouch residual rate for secondary batteries,
wherein a shaping die is disposed at the upper side, a
pressing punch is disposed at the lower side, a pouch
shaping metal is disposed between the shaping die and the
pressing punch, a holder or a roller is located at a
lateral inlet of each of the shaping die and the pressing
punch, and a heater is disposed in the shaping die, the
pressing punch, and the holder, or the roller.
[8] In Patent Document 1, when the pouch shaping
metal is shaped, corner portions of the pouch shaping
metal are heated by the heater to increase the residual
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rate and flexibility of the pouch shaping metal, whereby
it is possible to prevent cracks from being formed at
lower end corners of an electrode assembly receiving
portion.
[9] Patent Document 2 relates to a pouch shaping
apparatus having the following construction. The pouch
shaping apparatus includes a die having formed therein a
shaping space inwardly depressed from the upper surface
thereof, a first corner forming an opening of the shaping
space being filleted so as to have a first radius of
curvature; a holder disposed above the die, when a pouch
film is seated on the upper surface of the die, the
holder moving downwards to fix the pouch film while the
holder is in contact with the die in the state in which
the pouch film is interposed between the die and the
holder; and an electromagnetic force generation unit
disposed above the shaping space, the electromagnetic
force generation unit being configured to generate
electromagnetic force and to apply the generated
electromagnetic force to the shaping space.
[10] In Patent Document 2, the electromagnetic force
generation unit, which is disposed above the shaping
space, generates electromagnetic force and applies the
generated electromagnetic force toward the shaping space.
A cup portion is brought into tight contact with the
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pouch film along the shaping space by the electromagnetic
force (repulsive force; Lorentz force), whereby the pouch
film is drawn.
[11] Patent Document 3 relates to a battery case
shaping apparatus including a die, a punch, and a holder.
In Patent Document 3, a punch head having a lower
coefficient of friction of 0.04 to 0.2 than a
conventional punch is provided in order to prevent cracks
from being formed in a sheet type base material due to
deep drawing of the punch.
[12] Patent Documents 1 to 3 disclose a construction
for preventing the occurrence of cracks but do not
disclose a construction of providing an electromagnetic
field in order to reduce the force of friction between a
punch and a laminate sheet according to the present
invention.
[13] (Prior Art Documents)
[14] (Patent Document 1) Korean Patent Application
Publication No. 2018-0092174 (2018.08.17)
[15] (Patent Document 2) Korean Patent Application
Publication No. 2019-0098581 (2019.08.22)
[16] (Patent Document 3) Korean Patent Application
Publication No. 2018-0028194 (2018.03.16)
【Disclosure】
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【Technical Problem】
[17] The present invention has been made in view of
the above problems, and it is an object of the present
invention to provide a pouch-shaped battery case shaping
apparatus using an electromagnetic field capable of
reducing friction between a punch and a laminate sheet
when shaping a pouch-shaped battery case, thereby
preventing damage to the laminate sheet, and a pouchshaped
battery case shaping method using the same.
[18] It is another object of the present invention to
provide a pouch-shaped battery case shaping method
capable of improving shapeability of a laminate sheet.
[19] It is a further object of the present invention
to provide a pouch-shaped battery case shaping method
capable of increasing energy density.
【Technical Solution】
[20] In order to accomplish the above objects, the
present invention provides a pouch-shaped battery case
shaping apparatus including a punch configured to press a
laminate sheet in order to shape a pouch-shaped battery
case; a die in which an accommodation portion is formed,
the accommodation portion having a size corresponding to
an electrode assembly receiving portion that is shaped by
the punch; and a holder configured to fix the outer
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periphery of the laminate sheet, wherein a means
configured to generate an electromagnetic field is added
to the punch.
[21] In the pouch-shaped battery case shaping
apparatus according to the present invention, the means
configured to generate the electromagnetic field may be
a punch coil formed as the result of an electric wire
being wound.
[22] In the pouch-shaped battery case shaping
apparatus according to the present invention, the surface
of the punch configured to press the laminate sheet may extend and protrude outwardly from the center of the punch.

【Claim 1】 A pouch-shaped battery case shaping
apparatus comprising:
a punch configured to press a laminate sheet in
order to shape a pouch-shaped battery case;
a die in which an accommodation portion is formed,
the accommodation portion having a size corresponding to
an electrode assembly receiving portion that is shaped by
the punch; and
a holder configured to fix an outer periphery of the
laminate sheet,
wherein a means configured to generate an
electromagnetic field is added to the punch.
【Claim 2】 The pouch-shaped battery case shaping
apparatus according to claim 1, wherein the means
configured to generate the electromagnetic field is a
punch coil formed as a result of an electric wire being
wound.
【Claim 3】 The pouch-shaped battery case shaping
apparatus according to claim 1, wherein a surface of the
punch configured to press the laminate sheet extends and
protrudes outwardly from a center of the punch.
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【Claim 4】 The pouch-shaped battery case shaping
apparatus according to claim 3, wherein a crosssectional
shape of the extending and protruding portion
defines an acute angle.
【Claim 5】 The pouch-shaped battery case shaping
apparatus according to claim 4, wherein the acute corner
portion is rounded.
【Claim 6】 The pouch-shaped battery case shaping
apparatus according to claim 3, wherein a punch coil
formed as a result of an electric wire being wound is
added adjacent to the extending and protruding portion.
【Claim 7】 A pouch-shaped battery case shaping method
using the pouch-shaped battery case shaping apparatus
according to any one of claims 1 to 6, the pouch-shaped
battery case shaping method comprising:
S1) disposing the laminate sheet on the die;
S2) fixing the laminate sheet to the die using the
holder; and
S3) pressing the laminate sheet using the punch
having the means configured to generate the
electromagnetic field added thereto.
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【Claim 8】 The pouch-shaped battery case shaping
method according to claim 7, wherein the means
configured to generate the electromagnetic field is
operated when the punch presses the laminate sheet.
【Claim 9】 The pouch-shaped battery case shaping
method according to claim 8, wherein a metal layer of
the laminate sheet and the punch are vibrated by the
electromagnetic field generated as a result of an
alternating current supplied to the means configured to
generate the electromagnetic field.
【Claim 10】 The pouch-shaped battery case shaping
method according to claim 7, wherein the step S3) is
replaced by:
S3-1) a preliminary shaping step of pressing the
laminate sheet up to a portion of a depth of the
depressed portion of the die using the punch; and
S3-2) a step of generating vibration of a metal
layer of the laminate sheet using an electromagnetic
field generated by supplying alternating current to the
means configured to generate the electromagnetic field
of the punch in a state of the punch being inserted into
the depressed portion.
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【Claim 11】 The pouch-shaped battery case shaping
method according to claim 7, further comprising applying
single current and high current pulses to the means
configured to generate the electromagnetic field to
generate a strong electromagnetic impact.
【Claim 12】 A pouch-shaped battery case manufactured by
the pouch-shaped battery case shaping method according to
claim 7.
【Claim 13】 A secondary battery comprising the pouchshaped
battery case according to claim 12.