【DESCRIPTION】
【Invention Title】
FOLDABLE POUCH-SHAPED BATTERY CELL AND METHOD OF
MANUFACTURING THE SAME
【Technical Field】
[1] This application claims the benefit of priority
to Korean Patent Application No. 2020-0061358 filed on
May 22, 2020, the disclosure of which is incorporated
herein by reference in its entirety.
[2] The present invention relates to a foldable
pouch-shaped battery cell and a method of manufacturing
the same, and more particularly to a foldable pouchshaped
battery cell configured such that an uncoated
portion, which is a portion coated with no electrode
mixture, is formed at a portion of the battery cell to
be folded and a stepped structure having a recessed
shape is formed at the portion of a pouch-shaped battery
case corresponding to the uncoated portion, whereby it is
possible to prevent movement of the electrode assembly,
a method of manufacturing the same.
【Background Art】
[3] A lithium secondary battery, which is capable of
being charged and discharged, has been widely used as an
2
energy source for wireless mobile devices or wearable
devices, and has also been used as an energy source for
electric vehicles and hybrid electric vehicles presented
as alternatives to existing gasoline and diesel vehicles,
which cause air pollution.
[4] In addition, with an increase in kinds of
miniaturized multifunctional products and a trend of
emphasizing design in electronic devices, the number of
products based on new shapes, such as a shape including a
curve or a geometrical shape, other than conventional
simple structures, such as a planar structure and a
prismatic structure, has increased.
[5] Lithium secondary batteries having various shapes,
such as a stepped shape and a polygonal shape, other than
a rectangular shape, have been developed in order to
apply the lithium secondary batteries to such products
having various shapes.
[6] For example, for a smartphone, the side thereof
is curved in order to improve sensation of grip, and
flexible display products capable of being bent or folded
have come on the stage.
[7] In the case in which a rectangular battery cell
is used in a bendable or foldable device, there is a
problem in that dead space is formed in large numbers.
Therefore, it is necessary to develop a battery cell
3
capable of securing capacity while reducing dead space
even though the battery cell is mounted in a device
having an atypical shape.
[8] In connection therewith, Patent Document 1
discloses a secondary battery configured such that a
positive electrode active material layer and a negative
electrode active material layer are formed by coating so
as to be spaced apart from each other by a predetermined
distance and including a bending region configured to be
bent at an uncoated portion, which is not coated with the
positive electrode active material layer and the negative
electrode active material layer.
[9] The secondary battery disclosed in Patent
Document 1 is suitably applied to a long device but has a
problem in that a plurality of bending regions is formed,
whereby the uncoated portion is widened, and therefore
energy density is lowered.
[10] Patent Document 2 relates to a battery cell
including a current collector having at least one
uncoated portion that partitions an electrode mixture,
wherein the portion of a battery case at which the
uncoated portion is located is bent, whereby the shape of
the battery cell is changed.
[11] In Patent Document 2, an electrode assembly is
separated from the battery case, whereby there is a
4
problem in that a bent portion of the battery case and a
bent portion of the electrode assembly may be misaligned
with each other when the battery cell is bent.
[12] Patent Document 3 discloses a battery cell
configured such that a recess is formed in a sealing
portion in order to prevent occurrence of wrinkles at the
sealed portion when the battery cell is bent. In this
structure, however, an electrode mixture layer may be
separated from an electrode assembly when the electrode
assembly is bent.
[13] Therefore, there is a high necessary for a
battery cell applicable to devices having various shapes,
such as a foldable or bendable battery cell, and
technology capable of securing safety of the battery cell
while preventing a decrease in capacity of the battery
cell.
[14] (Prior Art Documents)
[15] (Patent Document 1) Korean Patent Application
Publication No. 2012-0022385 (2012.03.12)
[16] (Patent Document 2) Korean Patent Application
Publication No. 2017-0033513 (2017.03.27)
[17] (Patent Document 3) Korean Patent Application
Publication No. 2015-0096325 (2015.08.24)
【Disclosure】
5
【Technical Problem】
[18] The present invention has been made in view of
the above problems, and it is an object of the present
invention to provide a foldable pouch-shaped battery cell
configured such that an uncoated portion, which is a
portion coated with no electrode mixture, is formed at
an electrode and a stepped structure having a recessed
shape is formed at the portion of a pouch-shaped battery
case corresponding to the uncoated portion, whereby it is
possible to prevent dislocation of an electrode assembly,
and therefore safety of the pouch-shaped battery cell is
improved, and a method of manufacturing the same.
【Technical Solution】
[19] A pouch-shaped battery cell according to the
present invention to accomplish the above object is a
pouch-shaped battery cell having an electrode assembly
received in a pouch-shaped battery case, wherein the
electrode assembly includes positive electrodes and
negative electrodes, each of the positive electrodes and
the negative electrodes being having a structure in
which the length of the electrode in an overall width
direction is less than the length of the electrode in an
overall length direction, each of the positive
electrodes and the negative electrodes has an uncoated
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portion, which is a portion not coated with an electrode
mixture, extending parallel to outer peripheries of the
electrode in the overall width direction or outer
peripheries of the electrode in the overall length
direction and a coated portion, which is coated with the
electrode mixture, formed at the remaining portion of
the electrode excluding the uncoated portion, and a
stepped structure is formed at the part of the pouchshaped
battery case corresponding to the uncoated portion
so as to be recessed inwards.
[20] In the pouch-shaped battery cell according to the
present invention, positive electrode tabs and negative
electrode tabs may protrude from one of the outer
peripheries of the electrode assembly in the overall
width direction.
[21] In the pouch-shaped battery cell according to the
present invention, each of the positive electrodes and
the negative electrodes may have a first coated portion
and a second coated portion formed symmetrical or
asymmetrical with respect to the uncoated portion, and
each of the positive electrodes and the negative
electrodes may be folded at the uncoated portion.
[22] In addition, a positive electrode tab or a
negative electrode tab may protrude from one of the
first coated portion or the second coated portion.
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[23] In the pouch-shaped battery cell according to the
present invention, an insulating member may be added to
outer surfaces of a part of the uncoated portion and a
portion of the coated portion serving as a border
portion between the uncoated portion and the coated
portion.
[24] In addition, the insulating member may be an
insulation tape or an insulating solution.
[25] In the pouch-shaped battery cell according to the
present invention, a wrinkled folding line may be formed
at the uncoated portion.
[26] In the pouch-shaped battery cell according to the
present invention, the pouch-shaped battery case may
include a first battery case and a second battery case,
and a stepped portion may be formed at a portion of at
least one of the first battery case and the second
battery case corresponding to the uncoated portion so as
to be recessed inwards.
[27] In addition, the recessed stepped portion of the
pouch-shaped battery case may be attached to each of the
uppermost electrode and the lowermost electrode of the
electrode assembly.
[28] In the pouch-shaped battery cell according to the
present invention, the pouch-shaped battery case may be
folded as a result of the electrode assembly being folded,
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and a notch may be formed in a sealed portion located at
the portion of the pouch-shaped battery case that is
folded.
[29] In addition, the present invention provides a
method of manufacturing the pouch-shaped battery cell.
Specifically, the method includes (a) coating an
electrode sheet to form a coated portion, which is a
portion coated with an electrode mixture, and an
uncoated portion, which is a portion coated with no
electrode mixture; (b) adding an insulating member to
outer surfaces of a part of the coated portion and a
part of the uncoated portion as a border portion between
the coated portion and the uncoated portion; (c) rolling
the electrode sheet; and (d) slitting the electrode
sheet of step (c).
[30] In the method according to the present invention,
an insulating tape may be attached or an insulation
solution may be applied in step (b).
[31] The method according to the present invention may
include a process of manufacturing an electrode assembly
by stacking a positive electrode and a negative
electrode manufactured by cutting the electrode sheet
slit in step (d) with a separator interposed
therebetween, receiving the electrode assembly in a
pouch-shaped battery case having a stepped portion
9
formed thereat, and hermetically sealing the pouchshaped
battery case.
[32] In addition, the method according to the present
invention may further include a process of receiving the
electrode assembly in a pouch-shaped battery case having
stepped portions formed thereat and attaching each of
the uppermost electrode and the lowermost electrode of
the electrode assembly to a corresponding one of the
stepped portions of the pouch-shaped battery case.
【Advantageous Effects】
[33] As is apparent from the above description, a
pouch-shaped battery cell according to the present
invention is configured to have a structure in which an
uncoated portion, which is a portion coated with no
electrode mixture, is formed at each of a positive
electrode and a negative electrode, and an electrode
assembly is folded at the uncoated portion, whereby it is
possible to prevent separation of an electrode mixture
layer from an electrode current collector as a result of
folding.
[34] In addition, a stepped portion having a recessed
shape is formed at the portion of a pouch-shaped battery
case corresponding to the uncoated portion of the
electrode assembly, whereby it is possible to seat and
10
fix a coated portion of the electrode assembly onto a
protruding portion of the pouch-shaped battery case,
which relatively protrudes.
[35] Also, in the case in which the uncoated portion
of the electrode assembly is attached to the stepped
portion of the pouch-shaped battery case, it is possible
to more securely fix the position of the electrode
assembly. Consequently, it is possible to prevent
separation of the electrode assembly, and therefore it is
possible to prevent damage to electrode tabs and an
electrode lead.
【Description of Drawings】
[36] FIG. 1 is a plan view showing the state in which
electrodes according to the present invention are
stacked.
[37] FIG. 2 is a side view of an electrode according
to the present invention.
[38] FIG. 3 is a side view of an electrode having a
folding line formed thereat.
[39] FIG. 4 is a side view of pouch-shaped battery
cells according to the present invention.
[40] FIG. 5 is a partial enlarged view of a vertical
section of a pouch-shaped battery cell according to the
present invention.
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[41] FIG. 6 is a perspective view of a pouch-shaped
battery cell having a notch formed in a sealed portion
thereof.
[42] FIG. 7 is a perspective view showing a process
of upwardly bending a pouch-shaped battery cell according
to the present invention based on an x axis.
[43] FIG. 8 is a perspective view showing a process
of downwardly bending the pouch-shaped battery cell
according to the present invention based on the x axis.
[44] FIG. 9 is a perspective view showing a process
of upwardly bending a pouch-shaped battery cell according
to the present invention based on a y axis.
【Best Mode】
[45] Now, preferred embodiments of the present
invention will be described in detail with reference to
the accompanying drawings such that the preferred
embodiments of the present invention can be easily
implemented by a person having ordinary skill in the art
to which the present invention pertains. In describing
the principle of operation of the preferred embodiments
of the present invention in detail, however, a detailed
description of known functions and configurations
incorporated herein will be omitted when the same may
obscure the subject matter of the present invention.
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[46] In addition, the same reference numbers will be
used throughout the drawings to refer to parts that
perform similar functions or operations. In the case in
which one part is said to be connected to another part
throughout the specification, not only may the one part
be directly connected to the other part, but also, the
one part may be indirectly connected to the other part
via a further part. In addition, that a certain element
is included does not mean that other elements are
excluded, but means that such elements may be further
included unless mentioned otherwise.
[47] In addition, a description to embody elements
through limitation or addition may be applied to all
inventions, unless particularly restricted, and does not
limit a specific invention.
[48] Also, in the description of the invention and the
claims of the present application, singular forms are
intended to include plural forms unless mentioned
otherwise.
[49] Also, in the description of the invention and the
claims of the present application, “or” includes “and”
unless mentioned otherwise. Therefore, “including A or B”
means three cases, namely, the case including A, the case
including B, and the case including A and B.
[50] In addition, all numeric ranges include the
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lowest value, the highest value, and all intermediate
values therebetween unless the context clearly indicates
otherwise.
[51] Embodiments of the present invention will be
described in detail with reference to the accompanying
drawings.
[52] A pouch-shaped battery cell according to the
present invention is configured to have a structure in
which an electrode assembly is received in a pouchshaped
battery case made of a laminate sheet including
an outer resin layer, a barrier layer, and an inner
adhesive layer in a hermetically sealed state. The
electrode assembly may be a stacked type electrode
assembly, which is configured to have a structure in
which a positive electrode and a negative electrode are
stacked in the state in which a separator is interposed
therebetween, or a laminated and stacked type electrode
assembly, which is configured to have a structure in
which two or more bicells, each of which positive
electrodes and negative electrodes are disposed in the
state in which two separators are interposed
respectively therebetween, are laminated in a state of
being stacked.
[53] Each of the positive electrode and the negative
electrode is configured to have a rectangular planar
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shape of a structure in which the length of the
electrode in an overall width direction is less than the
length of the electrode in an overall length direction,
and has a structure in which an uncoated portion, which
is a portion coated with no electrode mixture, is formed
parallel to the outer peripheries of the electrode in
the overall width direction or the outer peripheries of
the electrode in the overall length direction and a
coated portion, which is coated with an electrode
mixture, is formed at the remaining portion of the
electrode excluding the uncoated portion.
[54] The pouch-shaped battery cell according to the
present invention is foldable, wherein the uncoated
portion is folded, whereby the pouch-shaped battery cell
is folded.
[55] In connection therewith, an electrode mixture
formed on an electrode current collector by coating may
be separated from the folding portion of the electrode
current collector when the pouch-shaped battery cell is
folded. In order to prevent this, in the present
invention, the uncoated portion is formed, and the pouchshaped
battery cell is folded at the uncoated portion,
whereby it is possible to prevent the above problem.
[56] FIG. 1 is a plan view showing the state in which
electrodes according to the present invention are
15
stacked, and FIG. 2 is a side view of an electrode
according to the present invention.
[57] Referring to FIG. 1, electrodes (a) and
electrodes (b) are shown. Referring to FIG. 2, a side
view of the positive electrode (a) of FIG. 1 is shown.
In FIG. 1, a separator interposed between a positive
electrode and a negative electrode is omitted for
convenience of description.
[58] The electrodes (a) and the electrodes (b) are
stacks of positive electrodes 110 and 210 and negative
electrodes 120 and 220 configured to have a structure in
which the length of the electrode in the overall width
direction, i.e. an x-axis direction, is less than the
length of the electrode in the overall length direction,
i.e. a y-axis direction. Each of positive electrode
tabs 112 and 212 and negative electrode tabs 122 and 222
protrudes from one of the outer peripheries of a
corresponding one of the electrodes in the overall width
direction.
[59] Each of the electrodes (a) has a structure in
which an uncoated portion, which is a portion coated
with no electrode mixture, is formed parallel to the
outer peripheries of the electrode in the overall width
direction. The positive electrode 110 has coated
portions 111 formed symmetrical with respect to an
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uncoated portion 115 formed parallel to the outer
peripheries of the electrode in the overall width
direction, and the negative electrode 120 has coated
portions 121 formed symmetrical with respect to an
uncoated portion 125 formed parallel to the outer
peripheries of the electrode in the overall width
direction.
[60] For the positive electrode 110, an insulating
member 113 is added to outer surfaces of a part of the
uncoated portion 115 and a part of each coated portion
111 as a border portion between the uncoated portion 115
and the coated portion 111. For the negative electrode
120, an insulating member 123 is added to outer surfaces
of a part of the uncoated portion 125 and a part of each
coated portion 121 as a border portion between the
uncoated portion 125 and the coated portion 121.
[61] Each of the electrodes (b) has a structure in
which an uncoated portion, which is a portion coated
with no electrode mixture, is formed parallel to the
outer peripheries of the electrode in the overall length
direction. The positive electrode 210 has coated
portions 211 formed symmetrical with respect to an
uncoated portion 215 formed parallel to the outer
peripheries of the electrode in the overall length
direction, and the negative electrode 220 has coated
17
portions 221 formed symmetrical with respect to an
uncoated portion 225 formed parallel to the outer
peripheries of the electrode in the overall length
direction.
[62] For the positive electrode 210, an insulating
member 213 is added to outer surfaces of a part of the
uncoated portion 215 and a part of each coated portion
211 as a border portion between the uncoated portion 215
and the coated portion 211. For the negative electrode
220, an insulating member 223 is added to outer surfaces
of a part of the uncoated portion 225 and a part of each
coated portion 221 as a border portion between the
uncoated portion 225 and the coated portion 221.
[63] Meanwhile, the present invention relates to a
pouch-shaped battery cell that is folded based on an
uncoated portion, and therefore coated portions may be
formed asymmetrical with respect to the uncoated portion,
unlike what is shown in FIGS. 1 and 2.
[64] Although the present invention relates to a
foldable pouch-shaped battery cell, it is preferable to
understand that the pouch-shaped battery cell does not
always remain folded when in use and may be folded or
unfolded as needed.
[65] Consequently, it is preferable for the electrode
tabs to protrude in one direction in the state in which
18
the pouch-shaped battery cell according to the present
invention is not folded. The electrode tabs protrude
from one of the outer peripheries of the electrode in
the overall width direction.
[66] In addition, on the assumption that, for the
electrodes (a), the coated portions 111 and 121 located
above the uncoated portions 115 and 125 are first coated
portions and the coated portions 111 and 121 located
under the uncoated portions 115 and 125 are second
coated portions, the positive electrode tab 112 and the
negative electrode tab 122 protrude from the first
coated portions. On the assumption that, for the
electrodes (b), the coated portions 211 and 221 located
on the left sides of the uncoated portions 215 and 225
are first coated portions and the coated portions 211
and 221 located on the right sides of the uncoated
portions 215 and 225 are second coated portions, the
positive electrode tab 212 and the negative electrode
tab 222 protrude from the first coated portions. Since
the positive electrode tab or the negative electrode tab
is formed at any one coated portion, as described above,
the positions of a positive electrode terminal and a
negative electrode terminal may be uniformly fixed
irrespective of whether the pouch-shaped battery cell is
folded or unfolded.
19
[67] Each of the insulating members 113 and 213 may be
a member configured to have a structure in which an
insulating layer is attached to an adhesive layer as a
substrate, such as an insulating tape. Consequently, the
insulating tape may be added to the border portion
between the coated portion and the uncoated portion by
attachment, or an insulating solution obtained by
dissolving an insulating material in a solvent may be
added to the border portion between the coated portion
and the uncoated portion by coating.
[68] The insulating layer of the insulating tape may
be made of cast polypropylene (CPP) or polyethylene
terephthalate (PET).
[69] The insulating solution may be manufactured, for
example, by mixing styrene butadiene rubber (SBR),
alumina (Al2O3), and carboxymethyl cellulose (CMC) in a
weight ratio of 80:20:0.008 to prepare a mixture and
adding 40 weight% of distilled water to the mixture.
[70] A method of manufacturing a pouch-shaped battery
cell according to the present invention may include (a)
a step of coating an electrode sheet to form a coated
portion, which is a portion coated with an electrode
mixture, and an uncoated portion, which is a portion
coated with no electrode mixture; (b) a step of adding
an insulating member to outer surfaces of a part of the
20
coated portion and a part of the uncoated portion as a
border portion between the coated portion and the
uncoated portion; (c) a step of rolling the electrode
sheet; and (d) a step of slitting the electrode sheet of
step (c).
[71] The insulating member may be formed on the
coated portion by coating so as to have a size of at
least 0.1 mm. Preferably, the insulating member is
formed on the coated portion by coating so as to overlap
the coated portion by less than 0.4 mm. In order to
prevent an increase in overall thickness of the
electrode due to addition of the insulating member,
however, it is preferable for the thickness of the
insulating member not to be greater than the thickness
of the coated portion based on the insulating member
formed on the uncoated portion by coating.
[72] Since the insulation member is added to the
border portion between the uncoated portion and the
coated portion, as in the present invention, it is
possible to prevent occurrence of short circuit due to
contact between the positive electrode and the negative
electrode even though the separator interposed between
the positive electrode and the negative electrode
shrinks.
[73] In connection therewith, since the area of the
21
coated portion of the negative electrode is generally
designed so as to be greater than the area of the coated
portion of the positive electrode, the coated portion of
the negative electrode is disposed in contact with the
coated portion of the positive electrode in the stacking
direction. In the case in which the separator shrinks
due to overheating of the electrode assembly, therefore,
short circuit may occur due to contact between the
coated portion of the negative electrode and the coated
portion of the positive electrode.
[74] In the present invention, since the insulating
member is added to the border between the coated portion
and the uncoated portion, it is possible to prevent
contact between the coated portion of the negative
electrode and the coated portion of the positive
electrode even though the separator shrinks.
[75] In the electrode according to the present
invention, it is preferable for the height of the
uncoated portion, which corresponds to the distance
between the first coated portion and the second coated
portion, to be uniformly formed in a lateral direction
of the uncoated portion perpendicular thereto. In order
to prevent the coated portion from being separated from
the electrode current collector even though the
electrode assembly is folded 180 degrees, the height of
22
the uncoated portion may be set in consideration of the
thickness of the electrode current collector and the
thickness of the coated portion formed on one surface or
opposite surfaces of the electrode current collector by
coating.
[76] FIG. 3 is a side view of an electrode having a
folding line formed thereat.
[77] Referring to FIG. 3, the electrode of FIG. 3 is
similar to the electrode of FIG. 2 but is different from
the electrode of FIG. 2 in that a wrinkled folding line
318 is formed at an uncoated portion 315.
[78] In the case in which the folding line 318 is
formed, as described above, stress concentrated on a
bent portion when the electrode is folded is dispersed,
whereby it is possible to prevent damage to the bent
portion.
[79] The above description of the electrode of FIG. 2
may be equally applied to an electrode tab, coated
portion, uncoated portion, and insulating member of the
electrode of FIG. 3.
[80] Meanwhile, the method of manufacturing the
pouch-shaped battery cell according to the present
invention may include a process of manufacturing an
electrode assembly by stacking a positive electrode and
a negative electrode manufactured by cutting the
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electrode sheet slit in step (d) in the state in which a
separator is interposed therebetween, receiving the
electrode assembly in a pouch-shaped battery case having
a stepped portion formed thereat, and hermetically
sealing the pouch-shaped battery case.
[81] FIG. 4 is a side view of pouch-shaped battery
cells according to the present invention.
[82] Referring to FIG. 4, a pouch-shaped battery cell
(a) and a pouch-shaped battery cell (b) include first
battery cases 431 and 531 and second battery cases 432
and 532, respectively. The first battery case 431 of
the pouch-shaped battery cell (a) has formed therein a
receiving portion 433 configured to receive an electrode
assembly, and a stepped portion 436 is formed at the
receiving portion 433 so as to be recessed inwards. The
stepped portion 436 is formed at a portion corresponding
to the portion of the electrode assembly at which an
uncoated portion is located. The second battery case
432 has a flat shape having no receiving portion formed
therein.
[83] A receiving portion 533 configured to receive an
electrode assembly is formed in each of the first
battery case 531 and the second battery case 532 of the
pouch-shaped battery cell (b), and a stepped portion 536
is formed at the receiving portion 533 so as to be
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recessed inwards. The stepped portion 536 is formed at
a portion corresponding to the portion of the electrode
assembly at which an uncoated portion is located.
[84] Since the pouch-shaped battery cell (a) and the
pouch-shaped battery cell (b) are configured
respectively such that the stepped portions 436 and 536
are formed so as to correspond to the portions of the
electrode assemblies at which the uncoated portions are
located, as described above, coated portions of the
electrode assemblies are received respectively in
protruding portions 437 and 537, which relatively
protrude, whereby fixation in position of the electrode
assemblies in the battery cases may be achieved.
[85] In addition, the method of manufacturing the
pouch-shaped battery cell according to the present
invention may further include a process of receiving the
electrode assembly in a pouch-shaped battery case having
a stepped portion formed thereat and attaching the
uppermost electrode and the lowermost electrode of the
electrode assembly to the stepped portion of the pouchshaped
battery case.
[86] In connection therewith, FIG. 5 is a partial
enlarged view of a vertical section of a pouch-shaped
battery cell according to the present invention.
[87] Referring to FIG. 5, an electrode assembly is
25
the electrode assembly (a) of FIG. 1, and the separator
is omitted for convenience of description. A battery
case is the battery case of the pouch-shaped battery cell
(b) shown in FIG. 4.
[88] The electrode assembly is a stacked type
electrode assembly, which is configured to have a
structure in which positive electrodes 110 and negative
electrodes 120 are alternately stacked in the state in
which separators are interposed respectively between the
positive electrodes and the negative electrodes. Each
of the positive electrodes 110 and the negative
electrodes 120 is provided with a coated portion and an
uncoated portion. A stepped portion of a first battery
case 531 is attached to the uncoated portion of the
negative electrode 120 located at the uppermost end of
the electrode assembly, and a second battery case 532 is
attached to the uncoated portion of the positive
electrode 110 located at the lowermost end of the
electrode assembly.
[89] Since the electrode assembly is coupled to the
pouch-shaped battery case, as described above, it is
possible to prevent movement of the electrode assembly
in the battery case due to external impact.
Consequently, it is possible to prevent damage to
electrode tabs and an electrode lead due to movement of
26
the electrode assembly.
[90] Pouch-shaped battery cells manufactured using
the method of manufacturing the pouch-shaped battery
cell described above are shown in FIGS. 6 to 9.
[91] FIG. 6 is a perspective view of a pouch-shaped
battery cell having a notch formed in a sealed portion
thereof.
[92] In the pouch-shaped battery cell according to the
present invention, a notch may be formed in a battery
case in order to prevent damage to the battery case due
to tensile force generated at a folding portion of the
battery case at the time of folding.
[93] Referring to FIG. 6, a stepped portion 636 and
receiving portions 633 are formed at each of a first
battery case 631 and a second battery case 632. In the
case in which the pouch-shaped battery case is folded
upwards based on the stepped portion 636, as shown in FIG.
6, a sealed portion of the pouch-shaped battery case may
be extended by the two receiving portions 633, which
protrude. Consequently, a notch 660 is formed in the
sealed portion of the portion of the pouch-shaped battery
case that is folded, as in the pouch-shaped battery case
of FIG. 6, whereby it is possible to prevent damage to
the pouch-shaped battery case or to prevent release of
sealing of the sealed portion.
27
[94] FIG. 7 is a perspective view showing a process
of upwardly bending a pouch-shaped battery cell according
to the present invention based on an x axis, and FIG. 8
is a perspective view showing a process of downwardly
bending the pouch-shaped battery cell according to the
present invention based on the x axis.
[95] Referring to FIGS. 7 and 8, the pouch-shaped
battery cell has a structure in which a stepped portion
736 is formed at a pouch-shaped battery case so as to be
parallel to the x axis, i.e. a structure in which a
stepped portion is formed at only a first battery case,
which is an upper battery case, as in the pouch-shaped
battery cell (a) of FIG. 4.
[96] Consequently, in the case in which the pouchshaped
battery cell is bent upwards, as shown in FIG. 7,
the height of an uncoated portion of an electrode
assembly and the distance between protruding portions 737
must be set in consideration of the height of the
protruding portions.
[97] However, in the case in which the pouch-shaped
battery cell is bent downwards, as shown in FIG. 8, the
height of the uncoated portion of the electrode assembly
and the distance between the protruding portions may be
set to be less than the height of the uncoated portion of
the electrode assembly of FIG. 7 and the distance between
28
the protruding portions, since no protruding portions are
formed on a second battery case, which is a lower
battery case.
[98] Unlike what is shown in FIG. 8, the pouch-shaped
battery cell may have a structure in which a stepped
portion and protruding portions are formed at each of the
first battery case and the second battery case, as in the
pouch-shaped battery cell (b) of FIG. 4.
[99] FIG. 9 is a perspective view showing a process
of upwardly bending a pouch-shaped battery cell according
to the present invention based on a y axis.
[100] Referring to FIG. 9, a pouch-shaped battery cell
that has a narrow and long shape may be applied depending
on the shape of a device. As shown in FIG. 9, it is
possible to manufacture the pouch-shaped battery cell so
as to be bent based on the y axis, which is parallel to
the overall length direction of the pouch-shaped battery
cell.
[101] The pouch-shaped battery cell of FIG. 9 has a
structure in which a stepped portion 836 is formed at a
pouch-shaped battery case so as to be parallel to the y
axis, i.e. a structure in which a stepped portion is
formed at only a first battery case, which is an upper
battery case, as in the pouch-shaped battery cell (a) of
FIG. 4.
29
[102] Consequently, the height of an uncoated portion
of an electrode assembly and the distance between
protruding portions 837 must be set in consideration of
the height of the protruding portions.
[103] Although FIG. 9 shows the case in which the
pouch-shaped battery cell is bent upwards, the pouchshaped
battery cell may be bent downwards, as shown in
FIG. 8.
[104] In addition, unlike what is shown in FIG. 9, the
pouch-shaped battery cell may have a structure in which a
stepped portion and protruding portions are formed at
each of the first battery case and the second battery
case, as in the pouch-shaped battery cell (b) of FIG. 4.
[105] As described above, the pouch-shaped battery cell
according to the present invention is configured such
that the uncoated portion is formed at the electrode
assembly and the stepped portion is formed at the pouchshaped
battery case so as to correspond to the uncoated
portion, whereby it is possible for a user to fold or
unfold the pouch-shaped battery cell when in use.
[106] In addition, since the electrode assembly and
the inner surface of the pouch-shaped battery case are
partially coupled to each other, it is possible to
prevent movement of the electrode assembly in the pouchshaped
battery case, and therefore it is possible to
30
improve safety of the pouch-shaped battery cell.
[107] Those skilled in the art to which the present
invention pertains will appreciate that various
applications and modifications are possible within the
category of the present invention based on the above
description.
[108] (Description of Reference Numerals)
[109] 110, 310: Positive electrodes
[110] 111, 121, 211, 221, 311: Coated portions
[111] 112, 212, 312: Positive electrode tabs
[112] 113, 123, 213, 223, 313: Insulating members
[113] 115, 125, 215, 225, 315: Uncoated portions
[114] 120, 220: Negative electrodes
[115] 122, 222: Negative electrode tabs
[116] 431, 531, 631: First battery cases
[117] 432, 532, 632: Second battery cases
[118] 433, 533, 633: Receiving portions
[119] 436, 536, 636, 736, 836: Stepped portions
[120] 437, 537, 737, 837: Protruding portions
[121] 660: Notch
【Industrial Applicability】
[122] As is apparent from the above description, a
pouch-shaped battery cell according to the present
invention is configured to have a structure in which an
31
uncoated portion, which is a portion coated with no
electrode mixture, is formed at each of a positive
electrode and a negative electrode, and an electrode
assembly is folded at the uncoated portion, whereby it is
possible to prevent separation of an electrode mixture
layer from an electrode current collector as a result of
folding.
[123] In addition, a stepped portion having a recessed
shape is formed at the portion of a pouch-shaped battery
case corresponding to the uncoated portion of the
electrode assembly, whereby it is possible to seat and
fix a coated portion of the electrode assembly onto a
protruding portion of the pouch-shaped battery case,
which relatively protrudes.
[124] Also, in the case in which the uncoated portion
of the electrode assembly is attached to the stepped
portion of the pouch-shaped battery case, it is possible
to more securely fix the position of the electrode
assembly. Consequently, it is possible to prevent
separation of the electrode assembly, and therefore it is
possible to prevent damage to electrode tabs and an electrode lead.

【CLAIMS】
【Claim 1】 A pouch-shaped battery cell having an
electrode assembly received in a pouch-shaped battery
case, wherein
the electrode assembly comprises positive electrodes
and negative electrodes, each of the positive electrodes
and the negative electrodes having a structure in which
a length of the electrode in an overall width direction
is less than a length of the electrode in an overall
length direction,
each of the positive electrodes and the negative
electrodes has an uncoated portion, which is a portion
not coated with an electrode mixture, extending parallel
to outer peripheries of the electrode in the overall
width direction or outer peripheries of the electrode in
the overall length direction and a coated portion, which
is coated with the electrode mixture, formed at a
remaining portion of the electrode excluding the
uncoated portion, and
a stepped structure is formed at a part of the
pouch-shaped battery case corresponding to the uncoated
portion so as to be recessed inwards.
【Claim 2】 The pouch-shaped battery cell according to
33
claim 1, wherein positive electrode tabs and negative
electrode tabs protrude from one of the outer
peripheries of the electrode assembly in the overall
width direction.
【Claim 3】 The pouch-shaped battery cell according to
claim 1, wherein each of the positive electrodes and the
negative electrodes has a first coated portion and a
second coated portion formed symmetrical or asymmetrical
with respect to the uncoated portion, and
wherein each of the positive electrodes and the
negative electrodes is folded at the uncoated portion.
【Claim 4】 The pouch-shaped battery cell according to
claim 3, wherein a positive electrode tab or a negative
electrode tab protrudes from one of the first coated
portion or the second coated portion.
【Claim 5】 The pouch-shaped battery cell according to
claim 1, wherein an insulating member is added to outer
surfaces of a part of the uncoated portion and a portion
of the coated portion serving as a border portion
between the uncoated portion and the coated portion.
【Claim 6】 The pouch-shaped battery cell according to
34
claim 5, wherein the insulating member is an insulation
tape or an insulating solution.
【Claim 7】 The pouch-shaped battery cell according to
claim 1, wherein a wrinkled folding line is formed at
the uncoated portion.
【Claim 8】 The pouch-shaped battery cell according to
claim 1, wherein the pouch-shaped battery case comprises
a first battery case and a second battery case, and
wherein a stepped portion is formed at a portion of
at least one of the first battery case and the second
battery case corresponding to the uncoated portion so as
to be recessed inwards.
【Claim 9】 The pouch-shaped battery cell according to
claim 8, wherein the recessed stepped portion of the
pouch-shaped battery case is attached to each of an
uppermost electrode and a lowermost electrode of the
electrode assembly.
【Claim 10】 The pouch-shaped battery cell according to
claim 1, wherein the pouch-shaped battery case is folded
as a result of the electrode assembly being folded, and
wherein a notch is formed in a sealed portion
35
located at a portion of the pouch-shaped battery case
that is folded.
【Claim 11】 A method of manufacturing the pouch-shaped
battery cell according to any one of claims 1 to 10, the
method comprising:
(a) coating an electrode sheet to form a coated
portion, which is a portion coated with an electrode
mixture, and an uncoated portion, which is a portion
coated with no electrode mixture;
(b) adding an insulating member to outer surfaces
of a part of the coated portion and a part of the
uncoated portion as a border portion between the coated
portion and the uncoated portion;
(c) rolling the electrode sheet; and
(d) slitting the electrode sheet of step (c).
【Claim 12】 The method according to claim 11, wherein
an insulating tape is attached or an insulation solution
is applied in step (b).
【Claim 13】 The method according to claim 11,
comprising a process of:
manufacturing an electrode assembly by stacking a
positive electrode and a negative electrode manufactured
36
by cutting the electrode sheet slit in step (d) with a
separator interposed therebetween;
receiving the electrode assembly in a pouch-shaped
battery case having a stepped portion formed thereat;
and
hermetically sealing the pouch-shaped battery case.
【Claim 14】 The method according to claim 13, further
comprising a process of:
receiving the electrode assembly in a pouch-shaped
battery case having stepped portions formed thereat; and
attaching each of an uppermost electrode and a
lowermost electrode of the electrode assembly to a
corresponding one of the stepped portions of the pouchshaped
battery case.
37
【ABSTRACT】
The present invention relates to a pouch-shaped
battery cell having an electrode assembly received in a
pouch-shaped battery case, wherein the electrode assembly
includes positive electrodes and negative electrodes,
each of the positive electrodes and the negative
electrodes having a structure in which the length of the
electrode in an overall width direction is less than the
length of the electrode in an overall length direction,
each of the positive electrodes and the negative
electrodes has an uncoated portion, which is a portion
coated with no electrode mixture, formed parallel to
outer peripheries of the electrode in the overall width
direction or outer peripheries of the electrode in the
overall length direction and a coated portion, which is
coated with an electrode mixture, formed at the
remaining portion of the electrode excluding the
uncoated portion, and a stepped structure is formed at
the part of the pouch-shaped battery case corresponding
to the uncoated portion so as to be recessed inwards.