【Technical Field】
[1] This application claims the benefit of priority
to Korean Patent Application No. 2020-0069118 filed on
June 8, 2020, the disclosure of which is incorporated
herein by reference in its entirety.
[2] The present invention relates to a method of
manufacturing an electrode including a folding portion
and an electrode sheet including the folding portion, and
more particularly to a method of manufacturing an
electrode including a folding portion usable to
manufacture a foldable battery cell and an electrode
sheet including the folding portion.
【Background Art】
[3] A lithium secondary battery, which is capable of
being charged and discharged, has been widely used as an
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,
2
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
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
3
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] However, 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
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 an electrode
4
configured to have a structure in which an electrode
active material is printed on a band type electrode
current collector so as to have a pattern repeated at
regular intervals.
[13] However, the invention disclosed in Patent
Document 3 relates to an electrode cut so as to have a
predetermined length and width, wherein the electrode is
received in a sheathing member in a state of being bent.
[14] As can be seen from the above description, each
of the above patent documents discloses only an electrode
including an uncoated portion that is coated with no
electrode mixture. Therefore, a method of manufacturing
an electrode having the above structure or research on
the shape of an electrode sheet is needed.
[15] (Prior Art Documents)
[16] (Patent Document 1) Korean Patent Application
Publication No. 2012-0022385 (2012.03.12)
[17] (Patent Document 2) Korean Patent Application
Publication No. 2017-0033513 (2017.03.27)
[18] (Patent Document 3) Japanese Patent Application
Publication No. 1995-153438 (1995.06.16)
【Disclosure】
【Technical Problem】
[19] The present invention has been made in view of
5
the above problems, and it is an object of the present
invention to provide a method of manufacturing an
electrode including a folding portion constituted by an
uncoated portion having no electrode mixture formed
thereon by coating in order to manufacture an electrode
for foldable battery cells and an electrode sheet
including the folding portion.
【Technical Solution】
[20] An electrode manufacturing method according to
the present invention to accomplish the above object
includes a coating step of forming an electrode mixture
coated portion on an electrode sheet so as to include an
uncoated portion having no electrode mixture formed
thereon by coating, a step of slitting the electrode
sheet into a plurality of unit electrode sheets, and a
step of notching the slit electrode sheet, wherein the
uncoated portion includes a first uncoated portion
formed so as to be parallel to a direction in which the
electrode sheet is taken out and a second uncoated
portion formed so as to be perpendicular to the
direction in which the electrode sheet is taken out.
[21] In the electrode manufacturing method according
to the present invention, the slitting step may be a step
of slitting the coated portion between the first
6
uncoated portion and another first uncoated portion
adjacent to the first uncoated portion.
[22] In the electrode manufacturing method according
to the present invention, the second uncoated portion may
be a folding portion, and the notching step may be a
step of cutting a coated portion located between the
second uncoated portion and another second uncoated
portion adjacent to the second uncoated portion to
manufacture a unit electrode.
[23] In the electrode manufacturing method according
to the present invention, the second uncoated portion may
include a notching portion and a folding portion, the
notching portion and the folding portion may be
alternately disposed, and a unit electrode may be
manufactured by notching the notching portion.
[24] In addition, the electrode manufacturing method
may include a step of forming the uncoated portion such
that the width of the notching portion and the width of
the folding portion are different from each other.
[25] In the electrode manufacturing method according
to the present invention, the notching step may include a
notching process for forming an electrode tab on the
first uncoated portion and a coated portion notching
process for manufacturing the unit electrode.
[26] In addition, the notching process for forming
7
the electrode tab and the coated portion notching
process may be simultaneously performed.
[27] In the electrode manufacturing method according
to the present invention, the notching step may include a
notching process for forming an electrode tab on the
first uncoated portion and a coated portion notching
process for manufacturing the unit electrode.
[28] In the electrode manufacturing method according
to the present invention, the notching process for
forming the electrode tab and the coated portion
notching process may be simultaneously performed.
[29] An electrode sheet according to the present
invention includes a coated portion having an electrode
mixture coated thereon and an uncoated portion having no
electrode mixture formed thereon by coating, wherein the
uncoated portion includes a first uncoated portion
formed so as to be parallel to a direction in which the
electrode sheet is taken out and a second uncoated
portion formed so as to be perpendicular to the
direction in which the electrode sheet is taken out, the
first uncoated portion is an electrode tab formation
portion, and the second uncoated portion includes a
notching portion and a folding portion.
[30] In the electrode sheet according to the present
invention, the notching portion and the folding portion
8
may be alternately arranged.
[31] An electrode tab may be formed at a boundary
portion between any one of a first coated portion and a
second coated portion formed on opposite sides of the
folding portion and the portion at which the electrode
tab is to be formed.
[32] In the electrode sheet according to the present
invention, the first coated portion and the second
coated portion are formed so as to have the same size.
[33] In the electrode sheet according to the present
invention, the width of the folding portion may be formed
so as to be greater than the width of the notching
portion.
[34] In the electrode sheet according to the present
invention, the width of the folding portion may be
greater than the thickness of the coated portion x π.
【Advantageous Effects】
[35] As is apparent from the above description, in an
electrode manufacturing method according to the present
invention, in order to form not only an uncoated portion,
which is an electrode tab formation portion, but also an
uncoated portion, which is configured to manufacture a
folded electrode, on an electrode sheet, a method of
coating a portion of the electrode sheet with an
9
electrode mixture is used, whereby it is possible to
reduce the number of manufacturing steps as compared to
a method of coating the entirety of the electrode sheet
with the electrode mixture and then removing the coating
and to reduce defects that may occur during a coating
removal process.
[36] Also, in a notching process for manufacturing a
unit electrode, notching is performed such that a folding
portion is included in the unit electrode, whereby it is
possible to obtain a unit electrode having a coated
portion and an uncoated portion formed so as to have
regular areas.
[37] In addition, when notching is performed such that
the folding portion is included in the unit electrode, an
electrode tab is formed at every other coated portion
formed on opposite sides of the portion at which the
electrode tab is to be formed in a direction in which
the electrode sheet is taken out. When unit electrodes
are stacked, therefore, electrode tabs may overlap in
the direction in which the unit electrodes are stacked.
【Description of Drawings】
[38] FIG. 1 is a plan view of an electrode sheet
according to an embodiment.
[39] FIG. 2 is a plan view showing a notching portion
10
formed in the electrode sheet of FIG. 1.
[40] FIG. 3 is a plan view of an electrode sheet
according to another embodiment.
[41] FIG. 4 is a vertical sectional view of the
electrode sheet of FIG. 3.
【Best Mode】
[42] 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.
[43] 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
11
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.
[44] Embodiments of the present invention will be
described in detail with reference to the accompanying
drawings.
[45] FIG. 1 is a plan view of an electrode sheet
according to an embodiment.
[46] An electrode manufacturing method according to
the present invention includes a coating step of forming
an electrode mixture coated portion on an electrode
sheet so as to include an uncoated portion having no
electrode mixture formed thereon by coating, a step of
slitting the electrode sheet into a plurality of unit
electrode sheets, and a step of notching the slit
electrode sheet.
[47] Referring to FIG. 1, an electrode mixture coated
portion 110 is formed at the electrode sheet while the
electrode sheet is taken out in an arrow direction. At
this time, the coated portion 110 is formed such that an
uncoated portion having no electrode mixture formed
thereon by coating is formed, wherein a first uncoated
portion 120 is formed so as to be parallel to a
direction in which the electrode sheet is taken out, and
12
a second uncoated portion 130 is formed so as to be
perpendicular to the direction in which the electrode
sheet is taken out.
[48] The coated portion may be formed at any one of
the upper surface and the lower surface of the electrode
sheet or may be formed at opposite surfaces of the
electrode sheet.
[49] The first uncoated portion 120 is an electrode
tab formation portion, and an electrode tab 102 of an
unit electrode 101 is formed at the first uncoated
portion 120.
[50] The second uncoated portion 130 is a folding
portion, which is a portion at which an electrode is
folded, and the unit electrode 101 is notched so as to
include the second uncoated portion 130.
[51] That is, a first coated portion 110a and a
second coated portion 110b are formed on opposite sides
of the second uncoated portion 130, an electrode tab is
formed at any one of the first coated portion 110a and
the second coated portion 110b, and the first coated
portion 110a and the second coated portion 110b have the
same size.
[52] The electrode sheet is slit into a plurality of
unit electrode sheets 150, and a slitting line 140 is
formed on a coating layer. Consequently, two unit
13
electrode sheets 150 are formed from the electrode sheet
of FIG. 1.
[53] However, the coated portion and the uncoated
portion may be formed such that two or more slitting
lines are formed depending on the width of the electrode
sheet and the size of the unit electrode, and the
slitting line may be formed so as to divide the coated
portion into two equal parts.
[54] That is, the slitting step may be performed
using a method of slitting a coated portion 110 located
between a first uncoated portion 120 and another first
uncoated portion 120 adjacent to the first uncoated
portion 120.
[55] FIG. 2 is a plan view showing a notching portion
formed in the electrode sheet of FIG. 1.
[56] Referring to FIG. 2, the notching step is a
process of punching the electrode sheet along outer
peripheries of an electrode tab and a unit electrode,
wherein, in order to form a unit electrode 101 indicated
by a thick dotted line, an electrode tab 102 and a
coated portion 110 located between a second uncoated
portion 130 and another second uncoated portion 130
adjacent to the second uncoated portion 130 are cut to
manufacture the unit electrode.
[57] The notching step includes a notching process
14
for forming an electrode tab 102 on the first uncoated
portion 120 and a coated portion notching process for
manufacturing a unit electrode, and the notching process
for forming the electrode tab and the coated portion
notching process may be sequentially performed.
[58] Alternatively, the notching process for forming
the electrode tab and the coated portion notching
process may be simultaneously performed. In the case in
which the notching process for forming the electrode tab
and the coated portion notching process are
simultaneously performed, it is possible to reduce an
electrode manufacturing time.
[59] FIG. 3 is a plan view of an electrode sheet
according to another embodiment.
[60] Referring to FIG. 3, a coated portion 210 is
formed at the electrode sheet while the electrode sheet
is taken out in an arrow direction. At this time, the
coated portion 210 is formed such that an uncoated
portion having no electrode mixture formed thereon by
coating is formed, wherein a first uncoated portion 220
is formed so as to be parallel to a direction in which
the electrode sheet is taken out, and a second uncoated
portion 230 is formed so as to be perpendicular to the
direction in which the electrode sheet is taken out.
[61] The first uncoated portion 220 is an electrode
15
tab formation portion, and an electrode tab 202 of a
unit electrode 201 indicated by a thick solid line is
formed at the first uncoated portion 220.
[62] The second uncoated portion 230 comprises a
folding portion 231, which is a portion at which an
electrode is folded, and a notching portion 232.
[63] In the present invention, a unit electrode is
formed so as to include the folding portion 231. The
folding portion 231 and the notching portion 232 are
alternately arranged in the direction in which the
electrode sheet is taken out, except the coated portion.
[64] A first coated portion 210a and a second coated
portion 210b are formed on opposite sides of the folding
portion 231 of the second uncoated portion 230, an
electrode tab is formed at any one of the first coated
portion 210a and the second coated portion 210b, and the
first coated portion 210a and the second coated portion
210b have the same size.
[65] In the electrode sheet of FIG. 3, the notching
portion 232 is formed as an uncoated portion, unlike the
electrode sheet of FIGS. 1 and 2. In the case in which
the notching portion 232 is widened, the coated portion
is narrowed, whereby the capacity of a battery cell may
be reduced. In the case in which the notching portion
232 is punched to manufacture an unit electrode, however,
16
it is possible to prevent occurrence of a problem in
that an electrode mixture layer is separated from the
coated portion or the coated portion is contaminated due
to powder generated from the electrode mixture layer in
the case in which the coated portion is punched.
[66] A step of notching the electrode sheet of FIG. 3
includes a notching process for forming an electrode tab
202 on a first uncoated portion 220 and a notching
portion 232 notching process for manufacturing a unit
electrode 201. The notching process for forming the
electrode tab and the notching portion notching process
may be sequentially performed.
[67] Alternatively, the notching process for forming
the electrode tab and the notching portion notching
process may be simultaneously performed. In the case in
which the notching process for forming the electrode tab
and the notching portion notching process are
simultaneously performed, it is possible to reduce an
electrode manufacturing time.
[68] FIG. 4 is a vertical sectional view of the
electrode sheet of FIG. 3.
[69] Referring to FIG. 4, on the assumption that the
direction in which the electrode sheet is taken out is a
width W2 direction of the notching portion 232 and a
width W1 direction of the folding portion 231, the width
17
W2 of the notching portion 232 and the width W1 of the
folding portion 231 may be formed so as to be different
from each other. For example, the width W2 of the
notching portion 232 may be formed so as to be less than
the width W1 of the folding portion 231.
[70] The folding portion 231 is disposed so as to
face each other in the state in which the electrode is
folded. It is preferable for the width W1 of the
folding portion 231 to be at least 1/2 of the
circumference of a circle having the thickness H of the
coated portion as a radius. Consequently, the width W1
of the folding portion 231 may be formed so as to be
greater than the thickness H of the coated portion x π.
[71] 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.
[72] (Description of Reference Symbols)
[73] 101, 201: Unit electrodes
[74] 102, 202: Electrode tabs
[75] 110, 210: Coated portions
[76] 110a, 210a: First coated portions
[77] 110b, 210b: Second coated portions
[78] 120, 220: First uncoated portions
18
[79] 130, 230: Second uncoated portions
[80] 140, 240: Slitting lines
[81] 150: Unit electrode sheet
[82] 231: Folding portion
[83] 232: Notching portion
[84] H: Thickness of coated portion
[85] W1: Width of folding portion
[86] W2: Width of notching portion
【Industrial Applicability】
[87] As is apparent from the above description, an
electrode manufacturing method according to the present
invention, in order to form not only an uncoated portion,
which is an electrode tab formation portion, but also an
uncoated portion, which is configured to manufacture a
folded electrode, on an electrode sheet, a method of
coating a portion of the electrode sheet with an
electrode mixture is used, whereby it is possible to
reduce the number of manufacturing steps as compared to
a method of coating the entirety of the electrode sheet
with the electrode mixture and then removing the coating
and to reduce defects that may occur during a coating
removal process.
[88] Also, in a notching process for manufacturing a
unit electrode, notching is performed such that a folding
19
portion is included in the unit electrode, whereby it is
possible to obtain a unit electrode having a coated
portion and an uncoated portion formed so as to have
regular areas.
[89] In addition, when notching is performed such that
the folding portion is included in the unit electrode, an
electrode tab is formed at every other coated portion
formed on opposite sides of the portion at which the
electrode tab is to be formed in a direction in which
the electrode sheet is taken out. When unit electrodes
are stacked, therefore, electrode tabs may overlap in
the direction in which the unit electrodes are stacked.

【CLAIMS】
【Claim 1】 An electrode manufacturing method
comprising:
a coating step of forming an electrode mixture
coated portion on an electrode sheet so as to include an
uncoated portion having no electrode mixture formed
thereon by coating;
a step of slitting the electrode sheet into a
plurality of unit electrode sheets; and
a step of notching the slit electrode sheet,
wherein the uncoated portion comprises:
a first uncoated portion formed so as to be
parallel to a direction in which the electrode sheet is
taken out; and
a second uncoated portion formed so as to be
perpendicular to the direction in which the electrode
sheet is taken out.
【Claim 2】 The electrode manufacturing method
according to claim 1, wherein the slitting step is a
step of slitting the coated portion between the first
uncoated portion and another first uncoated portion
adjacent to the first uncoated portion.
21
【Claim 3】 The electrode manufacturing method
according to claim 1, wherein
the second uncoated portion is a folding portion,
and
during the notching step, a coated portion located
between the second uncoated portion and another second
uncoated portion adjacent to the second uncoated portion
is cut to manufacture a unit electrode.
【Claim 4】 The electrode manufacturing method
according to claim 1, wherein
the second uncoated portion comprises a notching
portion and a folding portion,
the notching portion and the folding portion are
alternately disposed, and
a unit electrode is manufactured by notching the
notching portion.
【Claim 5】 The electrode manufacturing method
according to claim 4, comprising a step of forming the
uncoated portion such that a width of the notching
portion and a width of the folding portion are different
from each other.
【Claim 6】 The electrode manufacturing method
22
according to claim 3, wherein the notching step
comprises:
a notching process for forming an electrode tab on
the first uncoated portion; and
a coated portion notching process for manufacturing
the unit electrode.
【Claim 7】 The electrode manufacturing method
according to claim 6, wherein the notching process for
forming the electrode tab and the coated portion
notching process are simultaneously performed.
【Claim 8】 The electrode manufacturing method
according to claim 4, wherein the notching step
comprises:
a notching process for forming an electrode tab on
the first uncoated portion; and
a coated portion notching process for manufacturing
the unit electrode.
【Claim 9】 The electrode manufacturing method
according to claim 8, wherein the notching process for
forming the electrode tab and the coated portion
notching process are simultaneously performed.
23
【Claim 10】 An electrode sheet comprising:
a coated portion having an electrode mixture coated
thereon; and
an uncoated portion having no electrode mixture
formed thereon by coating,
wherein the uncoated portion comprises:
a first uncoated portion formed so as to be
parallel to a direction in which the electrode sheet is
taken out; and
a second uncoated portion formed so as to be
perpendicular to the direction in which the electrode
sheet is taken out,
the first uncoated portion is an electrode tab
formation portion, and
the second uncoated portion comprises a notching
portion and a folding portion.
【Claim 11】 The electrode sheet according to claim 10,
wherein the notching portion and the folding portion are
alternately arranged.
【Claim 12】 The electrode sheet according to claim 10,
wherein an electrode tab is formed at a boundary portion
between any one of a first coated portion and a second
coated portion formed on opposite sides of the folding
24
portion and the portion at which the electrode tab is to
be formed.
【Claim 13】 The electrode sheet according to claim 12,
wherein the first coated portion and the second coated
portion are formed so as to have an identical size.
【Claim 14】 The electrode sheet according to claim 10,
wherein a width of the folding portion is formed so as
to be greater than a width of the notching portion.
【Claim 15】 The electrode sheet according to claim 10,
wherein a width of the folding portion is greater than a
thickness of the coated portion x π.