U.S. patent application number 13/524299 was filed with the patent office on 2012-12-20 for pouch type secondary battery and method for manufacturing the same.
This patent application is currently assigned to SK INNOVATION CO., LTD.. Invention is credited to GYUSIK KIM, JONHA LEE, JAEMAN SEO.
Application Number | 20120321935 13/524299 |
Document ID | / |
Family ID | 46317200 |
Filed Date | 2012-12-20 |
United States Patent
Application |
20120321935 |
Kind Code |
A1 |
KIM; GYUSIK ; et
al. |
December 20, 2012 |
POUCH TYPE SECONDARY BATTERY AND METHOD FOR MANUFACTURING THE
SAME
Abstract
Provided are a pouch type secondary battery capable of
preventing corrosion of a metal layer due to exposure of the metal
layer to the outside at a distal end of a case thereof, and a
method for manufacturing the same.
Inventors: |
KIM; GYUSIK; (Cheongwon-gun,
KR) ; LEE; JONHA; (Cheonan-si, KR) ; SEO;
JAEMAN; (Daejeon, KR) |
Assignee: |
SK INNOVATION CO., LTD.
Seoul
KR
|
Family ID: |
46317200 |
Appl. No.: |
13/524299 |
Filed: |
June 15, 2012 |
Current U.S.
Class: |
429/151 ;
29/623.2 |
Current CPC
Class: |
H01M 2/0262 20130101;
H01M 10/05 20130101; H01M 2/0237 20130101; Y02E 60/10 20130101;
H01M 2/02 20130101; H01M 2002/0205 20130101; H01M 2/08 20130101;
Y10T 29/4911 20150115; H01M 2/0207 20130101; H01M 2/026 20130101;
H01M 2/0275 20130101; H01M 10/04 20130101 |
Class at
Publication: |
429/151 ;
29/623.2 |
International
Class: |
H01M 2/08 20060101
H01M002/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 16, 2011 |
KR |
10-2011-0058234 |
Claims
1. A pouch type secondary battery comprising: a battery assembly
including a plurality of electrodes; cases having an internal space
part in which the battery assembly is received; a sealing part
sealed by applying a sealant to a predetermined region of
circumferential surfaces of the cases bonded to each other so as to
integrate the cases with each other; and non-bonded parts extended
from the circumferential surfaces of the cases forming the sealing
part.
2. The pouch type secondary battery of claim 1, wherein the center
parts of the non-bonded parts are folded so that end portions of
the non-bonded parts are bonded to each other.
3. The pouch type secondary battery of claim 2, wherein the
non-bonded parts are sealed by applying the sealant to an outer
side of a point at which the non-bonded parts are bonded to each
other.
4. The pouch type secondary battery of claim 1, wherein the sealant
is a thermoplastic resin.
5. A method for manufacturing a pouch type secondary battery, the
method comprising: a primary sealing step of applying a sealant to
a predetermined region of circumferential surfaces of cases bonded
to each other so as to integrate the cases with each other to
perform sealing, thereby forming a sealing part and non-bonded
parts; a folding step of folding the non-bonded parts toward a
space therebetween to bond end portions of the non-bonded parts to
each other; and a secondary sealing step of inserting the sealant
into a point at which the non-bonded parts are folded to be bonded
to each other to perform sealing.
6. The method of claim 5, wherein the folding step includes a
primary folding step of vertically bending the center parts of the
non-bonded parts toward the space between the non-bonded parts.
7. The method of claim 6, wherein in the primary folding step, a
first bending jig of which both sides of one end portion are
inclined symmetrically to each other so that a cross section
increases is inserted into the space between the non-bonded parts
to support inner side surfaces of the non-bonded parts.
8. The method of claim 7, wherein in the primary folding step, a
bar shaped pressure jig supports outer side surfaces of the
non-bonded parts, and the first bending jig and the pressure jig
intersect with each other so as to be in parallel with each other
to vertically fold the center parts of the non-bonded parts.
9. The method of claim 6, wherein the folding step includes a
secondary folding step of folding the end portions of the
non-bonded parts vertically folded in the primary folding step so
as to be bonded to each other.
10. The method of claim 9, wherein in the secondary folding step,
the first bending jig and the pressure jig intersect with each
other so as to be in parallel with each other, and a second bending
jig formed in a shape corresponding to one end portion of the first
bending jig presses outer side surfaces of the non-bonded parts
toward the first bending jig to fold the end portions of the
non-bonded parts so as to be bonded to each other.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.119
to Korean Patent Application No. 10-2011-0058234, filed on Jun. 16,
2011, in the Korean Intellectual Property Office, the disclosure of
which is incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] The following disclosure relates to a pouch type secondary
battery and a method for manufacturing the same, and more
particularly, to a pouch type secondary battery capable of
preventing corrosion of a metal layer to exposure of the metal
layer to the outside at a distal end of a case thereof, and a
method for manufacturing the same.
BACKGROUND
[0003] Generally, research into a secondary battery capable of
being charged and discharged unlike a primary battery has been
actively conducted in accordance with the development of
state-of-the-art fields such as a digital camera, a cellular phone,
a laptop computer, a hybrid automobile, and the like. An example of
the secondary battery includes a nickel-cadmium battery, a
nickel-metal hydride battery, a nickel-hydrogen battery, and a
lithium secondary battery. Among them, the lithium secondary
battery, which has operating voltage of 3.6 V or more, is used as a
power supply of a portable electronic device or a plurality of
lithium secondary batteries are connected in series with each other
to thereby be used for a high output hybrid automobile. Since this
lithium secondary battery has operating voltage three times higher
than that of the nickel-cadmium battery or the nickel-metal hydride
battery and is more excellent in view of energy density
characteristics per unit weight than the nickel-cadmium battery or
the nickel-metal hydride battery, the use of the lithium secondary
battery has rapidly increased.
[0004] The lithium secondary battery may be manufactured in various
types. As a typical type of the lithium secondary battery, there
are a cylindrical type and a prismatic type that are mainly used
for a lithium ion battery. A lithium polymer battery that has been
recently spotlighted is manufactured in a pouch type having
flexibility, such that it has a relatively free shape.
[0005] In this pouch type lithium polymer battery (hereinafter,
referred to as a "pouch type secondary battery"), a battery
assembly including an anode, a separator, and a cathode is inserted
into a pouch type case, and an electrolyte is injected into the
pouch type case, and an edge of the pouch type case is then
sealed.
[0006] Generally, the case of the pouch type secondary battery is
made of a metal such as aluminum and a material coated in order
prevent corrosion of the metal. When this case is subjected to a
cutting process, a metal layer of the case is exposed to the
outside, such that metal layer may be corroded. In addition, a
local defect or a micro crack generated due to the corrosion of the
metal layer at a sealing part sealed after the electrolyte is
injected into the pouch type case becomes an electrical path to the
outside to cause dielectric breakdown of the battery and becomes a
moisture penetration path in the battery to significantly
deteriorate sealing strength.
SUMMARY
[0007] An embodiment of the present invention is directed to
providing a pouch type secondary battery capable of preventing
corrosion of a metal layer due to exposure of the metal layer to
the outside at a distal end of a case thereof, and a method for
manufacturing the same.
[0008] In one general aspect, a pouch type secondary battery 100
includes: a battery assembly 20 including a plurality of
electrodes; cases 10 having an internal space part in which the
battery assembly 20 is received; a sealing part 11 sealed by
applying a sealant 30 to a predetermined region of circumferential
surfaces of the cases 10 bonded to each other so as to integrate
the cases 10 with each other; and non-bonded parts 12 extended from
the circumferential surfaces of the cases 10 forming the sealing
part 11.
[0009] The center parts of the non-bonded parts 12 may be folded so
that end portions of the non-bonded parts 12 are bonded to each
other, the non-bonded parts 12 may be sealed by applying a sealant
30 to an outer side of a point at which the non-bonded parts are
bonded to each other, and the sealant 30 may be a thermoplastic
resin.
[0010] In another general aspect, a method for manufacturing a
pouch type secondary battery includes: a primary sealing step of
applying a sealant 30 to a predetermined region of circumferential
surfaces of cases 10 bonded to each other so as to integrate the
cases 10 with each other to perform sealing, thereby forming a
sealing part 11 and non-bonded parts 12; a folding step of folding
the non-bonded parts 12 toward a space therebetween to bond end
portions of the non-bonded parts to each other; and a secondary
sealing step of inserting the sealant 30 into a point at which the
non-bonded parts 12 are folded to be bonded to each other to
perform sealing.
[0011] The folding step may include a primary folding step of
vertically bending the center parts of the non-bonded parts 12
toward the space between the non-bonded parts 12.
[0012] In the primary folding step, a first bending jig 210 of
which both sides of one end portion are inclined symmetrically to
each other so that a cross section increases may be inserted into
the space between the non-bonded parts 12 to support inner side
surfaces of the non-bonded parts 12.
[0013] In the primary folding step, a bar shaped pressure jig 220
may support outer side surfaces of the non-bonded parts 12, and the
first bending jig 210 and the pressure jig 220 may intersect with
each other so as to be in parallel with each other to vertically
fold the center parts of the non-bonded parts 12.
[0014] The folding step may include a secondary folding step of
folding the end portions of the non-bonded parts 12 vertically
folded in the primary folding step so as to be bonded to each
other.
[0015] In the secondary folding step, the first bending jig 210 and
the pressure jig 220 may intersect with each other so as to be in
parallel with each other, and a second bending jig 230 formed in a
shape corresponding to one end portion of the first bending jig 210
may press outer side surfaces of the non-bonded parts 12 toward the
first bending jig 210 to fold the end portions of the non-bonded
parts 12 so as to be bonded to each other.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a cross-sectional view showing a primary sealing
step according to an exemplary embodiment of the present
invention.
[0017] FIG. 2 is a cross-sectional view showing a folding step
according to the exemplary embodiment of the present invention.
[0018] FIG. 3 is a cross-sectional view showing a secondary sealing
step according to the exemplary embodiment of the present
invention.
[0019] FIG. 4 is a cross-sectional view showing a process of
vertically bending the center side of a non-bonded part in the
folding step according to the exemplary embodiment of the present
invention.
[0020] FIG. 5 is a cross-sectional view showing a process of
folding the non-bonded part having the vertically bent center side
in the folding step according to the exemplary embodiment of the
present invention.
DETAILED DESCRIPTION OF MAIN ELEMENTS
[0021] 100: Pouch type secondary battery
[0022] 10: Case
[0023] 11: Sealing part
[0024] 12: Non-bonded part
[0025] 20: Battery assembly
[0026] 30: Sealant
[0027] 210: First bending jig
[0028] 220: Pressure jig
[0029] 230: Second bending jig
DETAILED DESCRIPTION OF EMBODIMENTS
[0030] Hereinafter, a technical spirit of the present invention
will be described in more detail with reference to the accompanying
drawings.
[0031] However, the accompanying drawings are only examples shown
in order to describe the technical idea of the present invention in
more detail. Therefore, the technical idea of the present invention
is not limited to shapes of the accompanying drawings.
[0032] FIG. 1 is a cross-sectional view showing a primary sealing
step according to an exemplary embodiment of the present invention;
FIG. 2 is a cross-sectional view showing a folding step according
to the exemplary embodiment of the present invention; FIG. 3 is a
cross-sectional view showing a secondary sealing step according to
the exemplary embodiment of the present invention; FIG. 4 is a
cross-sectional view showing a process of vertically bending the
center side of a non-bonded part in the folding step according to
the exemplary embodiment of the present invention; and FIG. 5 is a
cross-sectional view showing a process of folding the non-bonded
part 12 having the vertically bent center side in the folding step
according to the exemplary embodiment of the present invention.
[0033] The present invention relates to a pouch type secondary
battery 100 and a method for manufacturing the same, and more
particularly, to a pouch type secondary battery 100 capable of
preventing corrosion of a metal layer due to exposure of the metal
layer to the outside at a distal end of a case thereof, and a
method for manufacturing the same.
[0034] Referring to FIGS. 1 to 3, the pouch type secondary battery
100 according to an exemplary embodiment of the present invention
includes a pouch type case 10, a sealing part 11 sealed so that an
electrolyte injected into the case 10 is not leaked, and non-bonded
parts 12 formed by extending the case 10 to an outer side of the
sealing part 11, wherein sealing is performed between the
non-bonded parts 12 in a state in which the non-bonded parts 12 are
folded inwardly.
[0035] Referring to FIG. 1, the pouch type secondary battery 100
includes a battery assembly 20 provided in the case 10 and the
electrolyte injected thereinto, wherein the battery assembly 20
includes an anode, a separator, and a cathode.
[0036] Although not shown in the accompanying drawings, the case 10
may include a metal layer made of a metal such as aluminum, wherein
the metal layer may be coated in order to prevent corrosion of the
metal layer. In a process of cutting the case 10 as described
above, the metal layer is exposed to the outside.
[0037] In the pouch type secondary battery 100 according the
exemplary embodiment of the present invention as described above,
the sealing is performed one more time in a state in which the
distal ends of the non-bonded parts 121 at which the metal layer
included in the case 10 is exposed to the outside are folded
inwardly, thereby making it possible to prevent the corrosion of
the metal layer at the distal end of the case 10. Therefore, it is
possible to prevent dielectric breakdown or moisture penetration
due to a local defect or a micro crack generated due to the
corrosion of the metal layer at the sealing part 11 and increase
sealing strength.
[0038] A method for manufacturing a pouch type secondary battery
100 according to the exemplary embodiment of the present invention
includes a primary sealing step, a folding step, and a secondary
sealing step.
[0039] Referring to FIG. 1, in the pouch type secondary battery
100, the battery assembly 20 including the anode, the separator,
and the cathode is inserted into the pouch type case 10 and the
electrolyte is then injected into the pouch type case 10.
[0040] Referring to FIG. 1, in the primary sealing step of the
method for manufacturing a pouch type secondary battery 100
according to the exemplary embodiment of the present invention, the
sealing is performed so that the non-bonded parts 12 of the case 10
that are not bonded to each other are formed at an outer side of
the sealing part 11 formed by extending the case 10 into which the
electrolyte is injected so as to be long and sealed by heat and
pressure.
[0041] Referring to FIG. 2, in the folding step, the non-bonded
parts 12 are folded inwardly.
[0042] Although not shown in the accompanying drawings, the case 10
may include a metal layer made of a metal such as aluminum, wherein
the metal layer may be coated in order to prevent corrosion of the
metal layer. In a process of cutting the case 10 as described
above, the metal layer is exposed to the outside. The non-bonded
parts 12 are folded inwardly so that the distal end of the case 100
of which the metal layer is exposed to the outside due to the
cutting as described above is directed inwardly.
[0043] Here, the metal layer may be coated with a thermoplastic
resin such as polyvinyl chloride, polystyrene, polyethylene,
polypropylene, acrylic, nylon, or the like. The thermoplastic resin
may be softened and deformed by being again applied with heat even
after being molded through of application of the heat. The heat and
the pressure are applied to the cases 10 as described above,
thereby making it possible to perform the sealing so that the
thermoplastic resin may bond between the cases 10.
[0044] Referring to FIG. 3, in the secondary sealing step, a
sealant 30 is inserted into a space between the folded non-bonded
parts 12 and the heat is then applied the sealant 30 to seal
between the non-bonded parts 12.
[0045] In the method for manufacturing a pouch type secondary
battery 100 according the exemplary embodiment of the present
invention as described above, the sealing is secondarily performed
after the distal ends of the non-bonded parts 12 at which the metal
layer included in the case 10 is exposed to the outside are folded
inwardly, thereby making it possible to prevent the corrosion of
the metal layer at the distal end of the case 10. Therefore, it is
possible to prevent dielectric breakdown or moisture penetration
due to a local defect or a micro crack generated due to the
corrosion of the metal layer at the sealing part 11 and increase
sealing strength.
[0046] The sealant 30 used in the secondary sealing step may be a
thermoplastic resin.
[0047] In the secondary sealing step, since the sealant inserted
between the non-bonded parts 12 is used to seal between the
non-bonded parts 12 by being melted through the application of the
heat, it is preferable that the thermoplastic resin capable of
being softened and deformed by being again applied with the heat
even after being molded through the application of the heat is used
as the sealant 30.
[0048] The thermoplastic resin may be polypropylene, more
specifically, a polypropylene tape capable of being easily disposed
at a sealing position so that the polypropylene is not out of the
sealing position in a sealing process.
[0049] Referring to FIG. 4, the folding step may include a process
of vertically bending the center side of the non-bonded part 12.
Since the case 10 of the pouch type secondary battery 100 includes
the metal layer, it is not easy to fold the case 10 by a single
process. Therefore, it is preferable that the folding step includes
the process of bending the center side of the non-bonded part 12 so
as to be vertical to an inward direction.
[0050] In the folding step, the non-bonded part 12 may be folded by
a first bending jig 210 of which both side surfaces of one end
portion are inclined symmetrically to each other so that an area
increases, a pressure jig 220, and a second bending jig 230 formed
at one end portion of the first bending jig 210 so as to correspond
to the first bending jig 210.
[0051] Referring to FIGS. 4 and 5, the first bending jig 210
supports an inner side surface of the non-bonded part, the pressure
jig 220 intersects with the first bending jig 210 so as to be in
parallel with the first bending jig 210 while pressing an outer
side surface of the non-bonded part 12, such that the center side
of the non-bonded part 12 is vertically bent, and the second
bending jig 230 then presses the outer side surface of the
non-bonded part 12, thereby making it possible to easily fold the
non-bonded part 12.
[0052] With the pouch type secondary battery 100 and the method for
manufacturing the same as described above, the corrosion of the
metal layer generated due to the exposure of the metal layer to the
outside at the distal end of the case 10 of the pouch type
secondary battery 100 is prevented, thereby making it possible to
prevent the dielectric breakdown of the pouch type secondary
battery 100 or the moisture penetration due to the local defect or
the micro crack of the metal layer generated at the sealing part 11
and increase the sealing strength.
[0053] Hereinafter, the pouch type secondary battery and the method
for manufacturing the same according to the exemplary embodiment of
the present invention as described above will be described with
reference to the accompanying drawings.
[0054] Referring to FIG. 1, the battery assembly 20 is inserted
into the case 10 of the pouch type secondary battery 100, the
electrolyte is injected into the case 100, and the heat and the
pressure are the applied thereto so that the non-bonded parts 12
are formed at the outer side of the sealing part 11, thereby
performing the primary sealing.
[0055] Next, one cross section of the first bending jig 210 having
a wide area contacts the inner side surface of the non-bonded part
12. Referring to FIG. 4, the outer side surface of the non-bonded
part at a portion that does not contact the one cross section of
the first bending jig 210 is pressed using the pressure jig 220 to
bend the center side of the non-bonded part 12 so as to be vertical
to the inward direction. Here, the first bending jig 210 and the
pressure jig 220 intersect with each other so as to be parallel
with each other.
[0056] Referring to FIG. 5, when the center side of the non-bonded
part 12 is vertically bent, the outer side surface of the
non-bonded part 12 is pressed using the second bending jig 230
formed corresponding one end portion of the first bending jig 210
so that the non-bonded part 12 is folded.
[0057] The distal end of the non-bonded part 12 subjected to the
primary sealing step is folded inwardly as shown in FIG. 2 through
the above-mentioned process.
[0058] Next, as shown in FIG. 3, the sealant 30 is inserted between
the folded non-bonded parts 12 and the heat is applied to the
sealant 30 to seal between the non-bonded parts 12.
[0059] As set forth above, with the pouch type secondary battery
and the method for manufacturing the same according to the
exemplary embodiment of the present invention, the corrosion of the
metal layer generated due to the exposure of the metal layer to the
outside at the distal end of the case of the pouch type secondary
battery 100 is prevented, thereby making it possible to prevent the
dielectric breakdown of the pouch type secondary battery or the
moisture penetration due to the local defect or the micro crack of
the metal layer generated at the sealing part and increase the
sealing strength.
[0060] The present invention is not limited to the above-mentioned
exemplary embodiments, and may be variously applied, and may be
variously modified without departing from the gist of the present
invention claimed in the claims.
* * * * *