U.S. patent application number 15/171204 was filed with the patent office on 2016-12-08 for lithium secondary battery and secondary battery sub module comprising the same.
The applicant listed for this patent is SK Innovation Co., Ltd.. Invention is credited to Hee-Gyoung Kang.
Application Number | 20160359147 15/171204 |
Document ID | / |
Family ID | 57452852 |
Filed Date | 2016-12-08 |
United States Patent
Application |
20160359147 |
Kind Code |
A1 |
Kang; Hee-Gyoung |
December 8, 2016 |
Lithium Secondary Battery and Secondary Battery Sub Module
Comprising the Same
Abstract
The present invention provides a lithium secondary battery and a
lithium secondary battery sub module including the same. The
lithium secondary battery includes: an electrode assembly; a
plastic case which houses the electrode assembly and includes a gas
barrier layer; and a pouch film cover which seals the plastic case
having the electrode assembly housed therein, such that it is
possible to achieve a battery having a significantly increased
thickness so as to increase the capacity thereof without structural
limitation, secure durability of the battery due to having
excellent resistance to permeability, and improve productivity due
to a decrease in an occurrence of poor insulation. Thereby, the
lithium secondary battery sub module including the lithium
secondary battery may have a high energy density and may be formed
in a compact shape with reduced manufacturing costs.
Inventors: |
Kang; Hee-Gyoung; (Daejeon,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SK Innovation Co., Ltd. |
Seoul |
|
KR |
|
|
Family ID: |
57452852 |
Appl. No.: |
15/171204 |
Filed: |
June 2, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 10/625 20150401;
H01M 10/6555 20150401; Y02E 60/10 20130101; H01M 10/613 20150401;
Y02T 10/70 20130101; H01M 2/0285 20130101; Y02P 70/50 20151101;
H01M 2/043 20130101; H01M 10/052 20130101; H01M 10/6551 20150401;
H01M 2220/20 20130101; H01M 2/0262 20130101; H01M 2/0287
20130101 |
International
Class: |
H01M 2/02 20060101
H01M002/02; H01M 10/613 20060101 H01M010/613; H01M 10/625 20060101
H01M010/625; H01M 2/04 20060101 H01M002/04; H01M 10/6554 20060101
H01M010/6554; H01M 10/0525 20060101 H01M010/0525; H01M 10/6551
20060101 H01M010/6551 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 3, 2015 |
KR |
10-2015-0078723 |
Claims
1. A lithium secondary battery comprising: an electrode assembly; a
plastic case which houses the electrode assembly and includes a gas
barrier layer; and a pouch film cover which seals the plastic case
having the electrode assembly housed therein.
2. The lithium secondary battery according to claim 1, wherein the
plastic case is made of at least one selected from a group
consisting of polyethylene, polypropylene, polyethylene
terephthalate and polyethylene naphthalate.
3. The lithium secondary battery according to claim 1, wherein the
plastic case is injection mold.
4. The lithium secondary battery according to claim 1, wherein the
gas barrier layer includes at least one selected from a group
consisting of ethylene-vinyl alcohol copolymer; polyvinylidene
chloride; polyvinyl alcohol; nylon; polyamide; polyacrylonitrile,
linear low-density polyethylene, ethylene-vinyl alcohol copolymer,
and ionomer copolymer; a metal film; a coating layer made of at
least one selected from a group consisting of silica, alumina,
rubber, metal, glass and amorphous carbon; and a film having a
coating layer in which layered silicate nano particles are
dispersed in a polyvinyl alcohol binder.
5. The lithium secondary battery according to claim 1, wherein the
gas barrier layer is formed on an inner surface of the plastic
case.
6. The lithium secondary battery according to claim 1, wherein the
plastic case is formed in a plurality of layers, and the gas
barrier layer is included in an inner layer of the plastic
case.
7. The lithium secondary battery according to claim 1, wherein the
pouch film cover is a stacked film including an inner resin layer,
a metal thin film and an outer resin layer.
8. The lithium secondary battery according to claim 1, wherein the
inner resin layer contacting with the plastic case of the pouch
film cover is made of the same material as the plastic case.
9. A lithium secondary battery sub module comprising: a heat
radiation plate; and the lithium secondary batteries according to
claim 1, which are respectively disposed on both side of the heat
radiation plate, wherein the respective lithium secondary batteries
are disposed so that the pouch film covers face the heat radiation
plate.
10. A lithium secondary battery sub module comprising: a heat
radiation plate; and the lithium secondary batteries according to
claim 2, which are respectively disposed on both side of the heat
radiation plate, wherein the respective lithium secondary batteries
are disposed so that the pouch film covers face the heat radiation
plate.
11. A lithium secondary battery sub module comprising: a heat
radiation plate; and the lithium secondary batteries according to
claim 3, which are respectively disposed on both side of the heat
radiation plate, wherein the respective lithium secondary batteries
are disposed so that the pouch film covers face the heat radiation
plate.
12. A lithium secondary battery sub module comprising: a heat
radiation plate; and the lithium secondary batteries according to
claim 4, which are respectively disposed on both side of the heat
radiation plate, wherein the respective lithium secondary batteries
are disposed so that the pouch film covers face the heat radiation
plate.
13. A lithium secondary battery sub module comprising: a heat
radiation plate; and the lithium secondary batteries according to
claim 5, which are respectively disposed on both side of the heat
radiation plate, wherein the respective lithium secondary batteries
are disposed so that the pouch film covers face the heat radiation
plate.
14. A lithium secondary battery sub module comprising: a heat
radiation plate; and the lithium secondary batteries according to
claim 6, which are respectively disposed on both side of the heat
radiation plate, wherein the respective lithium secondary batteries
are disposed so that the pouch film covers face the heat radiation
plate.
15. A lithium secondary battery sub module comprising: a heat
radiation plate; and the lithium secondary batteries according to
claim 7, which are respectively disposed on both side of the heat
radiation plate, wherein the respective lithium secondary batteries
are disposed so that the pouch film covers face the heat radiation
plate.
16. A lithium secondary battery sub module comprising: a heat
radiation plate; and the lithium secondary batteries according to
claim 8, which are respectively disposed on both side of the heat
radiation plate, wherein the respective lithium secondary batteries
are disposed so that the pouch film covers face the heat radiation
plate.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Korean Patent
Application No. 10-2015-0078723 filed Jun. 3, 2015, the disclosure
of which is hereby incorporated in its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a lithium secondary battery
and a secondary battery sub module including the same.
[0004] 2. Description of the Related Art
[0005] Recently, a lithium secondary battery, which is rechargeable
and lightweight and has high energy and power densities, has been
widely used as an energy source for wireless mobile devices.
Further, as alternative plans to solve problems of air pollution
and greenhouse house with the existing internal combustion engine
vehicles using fossil fuels such as a gasoline vehicle and a diesel
vehicle, a hybrid electric vehicle (HEV), a plug-in hybrid electric
vehicle (PHEV), a battery electric vehicle (BEV), or the like have
been proposed. The lithium secondary battery has been drawn as a
power source for the alternative vehicles to the internal
combustion engine vehicles.
[0006] The lithium secondary battery is classified into a lithium
ion battery using a liquid electrolyte and a lithium polymer
battery using a polymer electrolyte depending on a type of
electrolytic solutions, and is classified into cylindrical,
prismatic, and a pouch types depending on a types of an exterior
material in which an electrode assembly is housed.
[0007] Among these, since the pouch type lithium secondary battery
has an appearance that is made of a metal layer (foil) and a pouch
film formed of multi-layers of a synthetic resin layer coated on
upper and lower surfaces of the metal layer, the weight of the
pouch type lithium secondary battery may be remarkably reduced than
that of the cylindrical lithium secondary battery or the prismatic
lithium secondary battery using a metallic can, such that the pouch
type lithium secondary battery may be lightweight and may be
changed to have various types.
[0008] However, since there is a limitation on a forming depth of
the pouch film in a structural aspect thereof, in order to achieve
the secondary battery having a thickness of 6 mm or more, the
formed pouch should be adhered by folding.
[0009] Korean Patent Laid-Open Publication No. 10-2013-0089614
discloses an exterior material forming composition for a secondary
battery which includes carbon fibers, ceramics and a solvent, and
an exterior material formed by including the same, however, did not
suggest an alternative idea to solve the above-described
problems.
SUMMARY OF THE INVENTION
[0010] Accordingly, it is an object of the present invention to
provide a lithium secondary battery which may achieve a
high-capacity without limitation on a battery thickness to have a
high energy density.
[0011] In addition, another object of the present invention is to
provide a lithium secondary battery having excellent resistance to
permeability and long-term durability.
[0012] Further, another object of the present invention is to
provide a lithium secondary battery sub module having a high energy
density with a compact shape, and reduced manufacturing costs.
[0013] In order to accomplish the above objects, according to an
aspect of the present invention, there is provided a lithium
secondary battery including: an electrode assembly; a plastic case
which houses the electrode assembly and includes a gas barrier
layer; and a pouch film cover which seals the plastic case having
the electrode assembly housed therein.
[0014] In an embodiment of the lithium secondary battery of the
present invention, the plastic case may be made of at least one
selected from a group consisting of polyethylene, polypropylene,
polyethylene terephthalate and polyethylene naphthalate.
[0015] In an embodiment of the lithium secondary battery of the
present invention, the plastic case may be injection mold.
[0016] In an embodiment of the lithium secondary battery of the
present invention, the gas barrier layer may include at least one
selected from a group consisting of ethylene-vinyl alcohol
copolymer; polyvinylidene chloride; polyvinyl alcohol; nylon;
polyamide; polyacrylonitrile, linear low-density polyethylene,
ethylene-vinyl alcohol copolymer, and ionomer copolymer; a metal
film; a coating layer made of at least one selected from a group
consisting of silica, alumina, rubber, metal, glass and amorphous
carbon; and a film having a coating layer in which layered silicate
nano particles are dispersed in a polyvinyl alcohol binder.
[0017] In an embodiment of the lithium secondary battery of the
present invention, the gas barrier layer may be formed on an inner
surface of the plastic case.
[0018] In an embodiment of the lithium secondary battery of the
present invention, the plastic case may be formed in a plurality of
layers, and the gas barrier layer is included in an inner layer of
the plastic case.
[0019] In an embodiment of the lithium secondary battery of the
present invention, the pouch film cover may be a stacked film
including an inner resin layer, a metal thin film and an outer
resin layer.
[0020] In an embodiment of the lithium secondary battery of the
present invention, the inner resin layer contacting with the
plastic case of the pouch film cover may be made of the same
material as the plastic case.
[0021] According to an aspect of the present invention, there is
provided a lithium secondary battery sub module including: a heat
radiation plate; and the lithium secondary batteries according to
the present invention, which are respectively disposed on both side
of the heat radiation plate, wherein the respective lithium
secondary batteries are disposed so that the pouch film covers face
the heat radiation plate.
[0022] The lithium secondary battery of the present invention may
achieve a battery having a significantly increased thickness to
increase the capacity thereof without structural limitation,
thereby having a higher energy density than the conventional
lithium secondary battery.
[0023] The lithium secondary battery of the present invention has
excellent resistance to permeability, such that it is possible to
secure durability of the battery.
[0024] The lithium secondary battery of the present invention is
made without a pouch forming process, such that it is possible to
improve productivity due to a decrease in an occurrence of poor
insulation.
[0025] Further, the lithium secondary battery sub module of the
present invention may have a high energy density and may be formed
in a compact shape, thus having economic advantages due to the
reduction of manufacturing costs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0027] FIG. 1 is a cross-sectional view schematically illustrating
a structure of a conventional pouch type secondary battery;
[0028] FIG. 2 is a cross-sectional view schematically illustrating
a structure of a lithium secondary battery according to an
embodiment of the present invention; and
[0029] FIG. 3 is a cross-sectional view schematically illustrating
a lithium secondary battery sub module according to an embodiment
of the present invention.
DESCRIPTION OF THE INVENTION
[0030] The present invention discloses a lithium secondary battery
including: an electrode assembly; a plastic case which houses the
electrode assembly and includes a gas barrier layer; and a pouch
film cover which seals the plastic case having the electrode
assembly housed therein, such that it is possible to achieve a
battery having a significantly increased thickness so as to
increase the capacity thereof without structural limitation, secure
durability of the battery due to having excellent resistance to
permeability, and improve productivity due to a decrease in an
occurrence of poor insulation. Thereby, the lithium secondary
battery sub module including the lithium secondary battery may have
a high energy density and may be formed in a compact shape with
reduced manufacturing costs.
[0031] FIG. 2 illustrates a lithium secondary battery according to
an embodiment of the present invention, and FIG. 3 illustrates a
lithium secondary battery sub module according to an embodiment of
the present invention.
[0032] Hereinafter, preferred embodiments of the present invention
will be described in detail with reference to the accompanying
drawings. However, since the drawings attached to the present
disclosure are only given for illustrating one of preferable
various embodiments of present invention to easily understand the
technical spirit of the present invention with the above-described
invention, it should not be construed as limited to such a
description illustrated in the drawings.
[0033] Lithium secondary Battery 40
[0034] Pouch Film Cover 10
[0035] The lithium secondary battery 40 of the present invention
includes an electrode assembly 30, a plastic case 20 in which the
electrode assembly 30 is contained, and a pouch film cover 10 which
seals the plastic case 20 having the electrode assembly 30 housed
therein.
[0036] Materials for forming the pouch film cover 10 may be any
material generally used for the pouch film in the related art, and
types thereof are not particularly limited within a range not
departing from the purpose of the present invention.
[0037] In particular, the pouch film cover 10 may be formed in a
multi-layer structure including, for example, an inner resin layer
which plays a role of a sealing material due to having sequential
thermal adhesiveness, and is made of polyethylene, polyolefin such
as non-stretched polypropylene or polypropylene, etc., or an
adhesive layer made of a copolymer thereof; a metal thin film which
plays a role of a base film for maintaining a mechanical strength
and a barrier layer against moisture and oxygen; and an outer resin
layer which functions to protect battery cells from an external
impact applied thereto, and is a functional polymer layer such as
polyethylene terephthalate and polyethylene naphthalate, nylon, or
a liquid crystal polymer resin, etc.
[0038] The above-described inner resin layer, metal thin film and
outer resin layer may be formed in a plurality of layers of two
layers or more, respectively, and any configuration known in the
related art other than the above-described layers may be applied to
the pouch film cover 10 of the present invention, without
particular limitation thereof.
[0039] Sealing between the pouch film cover 10 and the plastic case
20 may be performed by thermal fusion bonding in consideration of
characteristics of the used material, but it is not particularly
limited thereto so long as it is within a range without departing
from the purpose of the present invention.
[0040] Meanwhile, the inner resin layer contacting with the plastic
case 20 for increasing sealing properties therebetween may be made
of the same material as the plastic case 20.
[0041] Plastic Case 20
[0042] The plastic case 20 houses the electrode assembly 30 in an
inner space of the lithium secondary battery 40 of the present
invention, and includes a gas barrier layer.
[0043] As illustrated in FIG. 1, a conventional pouch type
secondary battery 3 is manufactured by a method including the
processes of inserting an electrode assembly 2 into a space formed
by pouch film covers 1, injecting electrolyte therein and sealing
the pouch film covers 1. However, when the battery has a thickness
of 6 mm or more, cracks occur in the pouch due to a limitation on a
forming depth of the pouch film in a structural aspect thereof.
Accordingly, in order to solve this problem, the secondary battery
3 is manufactured by a method of adhering the formed pouch film
covers 1 so as to face each other, however there is a structural
limitation for increasing a capacity of the battery in unit cells
due to the limitation on the forming depth of the pouch film.
[0044] Therefore, in the present invention, a space capable of
containing the electrode assembly 30 is formed by the plastic case
20 including the gas barrier layer, and the electrode assembly 30
is housed in the space, and then the space is covered with the
pouch film cover 10 and is sealed by the thermal fusion bonding.
Thereby, since there is no actual limitation on a form to be formed
in an aspect of characteristics of the plastic material, it is
possible to achieve a secondary battery with no limitation on the
thickness thereof. Accordingly, it is possible to achieve a
high-capacity secondary battery that could not be achieved by the
conventional secondary battery, such that the energy density of the
lithium secondary battery may be increased.
[0045] Meanwhile, since most plastic materials are permeable, when
using the plastic material as an exterior material of the battery,
there may be a problem entailed in long-term durability. Therefore,
the lithium secondary battery 40 of the present invention is
configured in such a way that the plastic case 20 includes the gas
barrier layer, and thereby resistance to permeability may be
secured, and an inlet and outlet of a gas between an inside and
outside of the battery may be prevented so as to provide long-term
durability.
[0046] In addition, since the secondary battery of the present
invention is manufactured without a process of forming the pouch as
in the related art, it is possible to improved productivity upon
manufacturing due to a decrease in an occurrence of poor
insulation.
[0047] Types of the material for forming the plastic case 20
according to the present invention are not particularly limited,
but as a particular example, may include at least one selected from
a group consisting of polyethylene, polypropylene, polyethylene
terephthalate and polyethylene naphthalate, which are preferable in
terms of securing the molding workability, sealing properties and
insulation properties.
[0048] In the present invention, it is possible to achieve a
battery having a large thickness by adjusting a shape of the
plastic case 20 according to the present invention. In this regard,
a processing method of the plastic case 20 is not particularly
limited, but an injection molding method is preferably used in an
aspect of the form of a battery case.
[0049] The gas barrier layer according to the present invention is
not particularly limited, but as a particular example, may include
at least one selected from a group consisting of ethylene-vinyl
alcohol copolymer; polyvinylidene chloride; polyvinyl alcohol;
nylon; polyamide; polyacrylonitrile, linear low-density
polyethylene, ethylene-vinyl alcohol copolymer, and ionomer
copolymer; a metal film; a coating layer made of at least one
selected from a group consisting of silica, alumina, rubber, metal,
glass and amorphous carbon; and a film having a coating layer in
which layered silicate nano particles are dispersed in a polyvinyl
alcohol binder, which are preferable in terms of securing the
workability and resistance to permeability.
[0050] In one embodiment of the present invention, the gas barrier
layer is formed on an inner surface of the plastic case 20, and may
be located so as to contact with the electrode assembly 30 housed
inside the plastic case 20.
[0051] In another embodiment of the present invention, when the
plastic case 20 has a multi-layer structure including one or more
plastic layers on upper and lower portions of the gas barrier
layer, respectively, the gas barrier layer is included as an inner
layer of the plastic case 20. More particularly, when the material
of the plastic case 20 is polypropylene, it may be a multi-layer
structure of polypropylene/gas barrier layer/polypropylene which
are sequentially stacked in this order.
[0052] Electrode Assembly 30
[0053] The electrode assembly 30 included in the lithium secondary
battery 40 of the present invention is known in the related art,
and may have any shape so long as it is within a range not
departing from the purpose of the present invention. As a
particular example, it may have the same shape as the electrode
assembly 30 to be described below, but it is not limited
thereto.
[0054] According to one embodiment of the present invention, the
electrode assembly 30 may have a shape in which a cathode plate, a
separator, and an anode plate are disposed in this order to be
wound in one direction, or a plurality of cathode plates,
separators, and anode plates are stacked. Each of the cathode and
anode plates may be electrically connected with a cathode tap and
an anode tap, and in the cathode and anode plates, one end portion
of the respective cathode and anode taps may protrude to an outside
through a lead. The one end portion of the protruded lead may be
connected with an external terminal (not illustrated). Outer
surfaces of the leads may be wound by an electrode tape,
respectively, in order to prevent an electrical short circuit
between a body and cover of the case and the leads at a portion
contacting with an outer portion.
[0055] The lithium secondary battery 40 according to the present
invention may be applied to medium and large size battery modules
or battery packs to be used as a unit cell. The medium and large
size battery modules or battery packs may be used as a power source
for medium and large size devices such as one or more of an
electric vehicle (EV) including a hybrid electric vehicle (HEV), a
plug-in hybrid electric vehicle (PHEV); an electric truck; an
electric bus & truck; and an energy storage system.
[0056] The medium and large size battery modules are configured in
such a way that a plurality of unit cells are connected with each
other in a series manner or series/parallel manner to provide a
high capacity, which are known in the related art, and therefore
will not described in detail in the present disclosure.
[0057] Lithium Secondary Battery Sub Module 60
[0058] The present invention also provides the lithium secondary
battery sub module 60 which includes the lithium secondary
batteries of the present invention disposed on both sides of a heat
radiation plate 50, wherein the lithium secondary batteries 40 are
disposed so that the pouch film covers 10 face the heat radiation
plate 50.
[0059] The lithium secondary battery sub module 60 of the present
invention includes the heat radiation plate 50 between the unit
lithium secondary batteries 40 so as to absorb and radiate heat
generated inside the battery to the outside. The heat radiation
plate 50 may be made of aluminum, copper, or the like, but it is
not particularly limited thereto.
[0060] The above-described lithium secondary batteries 40 of the
present invention are disposed on both sides of the heat radiation
plate 50. In this case, as described above, the lithium secondary
batteries 40 are disposed so that the pouch film covers 10 face the
heat radiation plate 50.
[0061] The conventional secondary battery sub module using the
pouch type unit lithium secondary battery needs a separate cell
cover for protecting the pouch type secondary battery on the
outside of the module. However, the lithium secondary battery sub
module according to the present invention does not need a separate
cell cover, because the plastic cases 20 are disposed on the
outside of the module.
[0062] Accordingly, the lithium secondary battery sub module 60 of
the present invention has a higher energy density than the
conventional secondary battery sub module including the lithium
secondary battery, as well as may achieve a compact shape due to
excluding a separate cell cover or panel part by a stiffness of the
plastic case 20, and thereby has economic advantages due to the
reduction of manufacturing costs.
DESCRIPTION OF REFERENCE NUMERALS
[0063] 1, 10: pouch film cover
[0064] 20: plastic case
[0065] 2, 30: electrode assembly
[0066] 3, 40: lithium secondary battery
[0067] 50: heat radiation plate
[0068] 60: lithium secondary battery sub module
* * * * *