【Technical Field】
[1] This application claims the benefit of priority
to Korean Patent Application No. 2020-0053494 filed on
May 4, 2020, the disclosure of which is incorporated
herein by reference in its entirety.
[2] The present invention relates to a battery module
having a fire-extinguishing unit including a fireextinguishing
material, and more particularly to a
battery module having a fire-extinguishing unit including
a fire-extinguishing material capable of extinguishing
fire in a battery cell without a sensing device when
thermal runaway occurs in the battery cell, whereby it is
possible to improve safety and energy density of the
battery module.
[3]
【Background Art】
[4] A secondary battery, which has high ease of
application based on product family and electrical
characteristics, such as high energy density, has been
2
universally applied to an electric vehicle (EV) or a
hybrid electric vehicle (HEV) driven by an electrical
driving source as well as portable devices. Such a
secondary battery has attracted attention as a new energy
source capable of enhancing environmental friendliness
and energy efficiency in that the secondary battery has a
primary advantage of remarkably reducing the use of
fossil fuels and in that no by-products due to the use of
energy are generated.
[5] There are a lithium ion battery, a lithium
polymer battery, a nickel-cadmium battery, a nickelhydride
battery, and a nickel-zinc battery as secondary
batteries that are widely used at present. The operating
voltage of such a unit secondary battery cell, i.e. a
unit battery cell, is about 2.5V to 4.5V. In the case in
which output voltage higher than the above operating
voltage is required, therefore, a plurality of battery
cells may be connected to each other in series to
constitute a battery module.
[6] Of course, a plurality of battery modules may be
connected to each other in parallel or in series
depending on required charge and discharge capacities to
constitute a battery pack.
[7] Meanwhile, in order to satisfy required output
voltage, a plurality of battery cells is received in a
3
battery module. The received battery cells are disposed
in tight contact with each other in order to improve
energy density. When an issue, such as thermal runaway,
occurs, therefore, a secondary accident, such as outbreak
of fire, may occur.
[8] FIG. 1 is a perspective view illustrating a
battery module having a conventional fire extinguisher.
Referring to FIG. 1, the battery module is configured
such that a fire extinguisher 20 containing a fireextinguishing
material is located between a plurality of
battery cells 10 and such that a rupture portion (not
shown), which is made of a shape memory alloy and which
is formed in the shape of a spring having a pointed end,
is provided in an injection portion 21 located at the
lower part of the fire extinguisher 20. At ordinary
times, the rupture portion is located so as to be shorter
than the height of a clogged part of the injection
portion 21. When heat is generated from the battery
cells 10 due to thermal runaway or the like, the rupture
portion is increased in length to form a hole in the
injection portion 21 such that the fire-extinguishing
material is injected therethrough.
[9] In the conventional art, the rupture portion, the
shape of which is changed depending on temperature, is
surrounded by the injection portion 21 and is spaced
4
apart from the battery cells 10, from which heat is
generated, by a predetermined distance, whereby it is
difficult to inject the fire-extinguishing material in a
timely manner. Furthermore, an additional device and
space are necessary to fix the fire extinguisher 20 in
the battery module, whereby a manufacturing process is
complicated and energy density is low.
[10]
[11] (Prior Art Document)
[12] (Patent Document 1) Korean Patent Application
Publication No. 2019-0041725
[13]
【Disclosure】
【Technical Problem】
[14] The present invention has been made in view of
the above problems, and it is an object of the present
invention to provide a battery module having a fireextinguishing
unit including a fire-extinguishing
material capable of sensitively responding to change in
heat of the battery module to secure safety, whereby it
is possible to reduce a secondary accident rate.
[15] It is another object of the present invention to
provide a battery module having a fire-extinguishing unit
including a fire-extinguishing material capable of
5
improving space utilization in the battery module while
maintaining fire-extinguishing performance, whereby it is
possible to improve energy density.
[16]
【Technical Solution】
[17] In order to accomplish the above objects, a
battery module according to the present invention
includes a plurality of battery cells (100) stacked in a
vertical direction or a horizontal direction and a fireextinguishing
unit (200) located adjacent to each of the
battery cells (100), wherein the fire-extinguishing unit
(200) includes a fire-extinguishing pack (210) containing
a fire-extinguishing material and at least one breaking
unit (220) interposed between the battery cell (100) and
the fire-extinguishing pack (210).
[18] Also, in the battery module according to the
present invention, the fire-extinguishing pack (210) may
be in tight contact with one surface or opposite surfaces
of the battery cell (100).
[19] Also, in the battery module according to the
present invention, the breaking unit (220) may be a
coupling portion (221) fixed to the battery cell (100) or
the fire-extinguishing pack (210) and a blade portion
(222) extending from the coupling portion (221), and the
6
blade portion (222) may be made of a shape memory alloy.
[20] Also, in the battery module according to the
present invention, when the temperature of the battery
cell (100) increases to a predetermined temperature or
higher, the blade portion (222) may be deformed by a
predetermined angle to rupture the fire-extinguishing
pack (210).
[21] Also, in the battery module according to the
present invention, the breaking unit (220) may be located
adjacent to an electrode lead (110) of the battery cell
(100).
[22] Also, in the battery module according to the
present invention, the blade portion (222) may be
provided along the edge of the coupling portion (221) in
plural.
[23] Also, in the battery module according to the
present invention, the blade portion (222) may extend so
as to have a thickness equal to the thickness of the
coupling portion (221).
[24] Also, in the battery module according to the
present invention, the blade portion (222) may have a
thickness gradually decreasing with increasing distance
from the edge of the coupling portion (221).
[25] Also, in the battery module according to the
present invention, a recessed portion (223) may be formed
7
in the portion at which the blade portion (222) and the
coupling portion (221) are connected to each other.
[26] In addition, a battery pack according to the
present invention includes the battery module.
[27]
【Advantageous Effects】
[28] A battery module having a fire-extinguishing unit
including a fire-extinguishing material according to the
present invention has an advantage in that a breaking
unit made of a shape memory alloy, which is deformed at a
predetermined temperature or higher, is located in tight
contact with a battery cell, whereby it is possible to
extinguish fire without recognition through a separate
sensing device, and therefore it is possible to prevent
non-operation due to systemic errors.
[29] In addition, the battery module according to the
present invention has an advantage in that a sensing
device configured to sense temperature or voltage of the
battery module and a separate device configured to fix
the breaking unit are not necessary, whereby a
manufacturing process is simple and energy density is
improved.
[30]
8
【Description of Drawings】
[31] FIG. 1 is a perspective view illustrating
extinguishment of fire in a battery module using a
conventional fire-extinguishing unit.
[32] FIG. 2 is a perspective view and a side front
view of a battery module according to a first preferred
embodiment of the present invention.
[33] FIG. 3 is an exploded perspective view of a
battery cell and a fire-extinguishing unit according to a
first preferred embodiment of the present invention.
[34] FIG. 4 is a view illustrating change of the
fire-extinguishing unit depending on temperature in the
battery cell according to the first preferred embodiment
of the present invention.
[35] FIG. 5 is a plan view illustrating breaking
units according to second and third preferred
embodiments of the present invention.
[36] FIG. 6 is a sectional view illustrating breaking
units according to preferred modifications of the
present invention.
[37]
【Best Mode】
[38] In the present application, it should be
understood that the terms “comprises,” “has,” “includes,”
9
etc. specify the presence of stated features, numbers,
steps, operations, elements, components, or combinations
thereof, but do not preclude the presence or addition of
one or more other features, numbers, steps, operations,
elements, components, or combinations thereof.
[39] 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 in
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.
[40]
[41] Hereinafter, a battery module having a fireextinguishing
unit including a fire-extinguishing
material according to the present invention will be
described with reference to the accompanying drawings.
[42] FIG. 2 is a perspective view and a side front
view of a battery module according to a first preferred
embodiment of the present invention, and FIG. 3 is an
exploded perspective view of a battery cell and a fire10
extinguishing unit according to a first preferred
embodiment of the present invention.
[43] Referring to FIGS. 2 and 3, the battery module
having the fire-extinguishing unit according to the
present invention includes a plurality of battery cells
100 and a fire-extinguishing unit 200.
[44] First, the plurality of battery cells 100 may be
stacked side by side in a vertical direction or in a
horizontal direction with respect to the ground and may
be connected to each other in series and in parallel.
[45] Here, it is preferable for each of the battery
cells 100 to be a pouch-shaped battery cell including a
cell assembly (not shown), a cell case, and a pair of
electrode leads 110. The cell assembly may be a jellyroll
type cell assembly, which is configured to have a
structure in which a long sheet type positive electrode
and a long sheet type negative electrode are wound in
the state in which a separator is interposed
therebetween, a stacked type cell assembly including unit
cells, each of which is configured to have a structure in
which a rectangular positive electrode and a rectangular
negative electrode are stacked in the state in which a
separator is interposed therebetween, a stacked and
folded type cell assembly, which is configured to have a
structure in which unit cells are wound using a long
11
separation film, or a laminated and stacked type cell
assembly, which is configured to have a structure in
which unit cells are stacked in the state in which a
separator is interposed therebetween and are then
attached to each other. However, the present invention
is not limited thereto.
[46] The cell assembly is mounted in the cell case.
The cell case is generally configured to have a laminate
sheet structure including an inner layer, a metal layer,
and an outer layer. The inner layer is disposed in
direct contact with the cell assembly, and therefore the
inner layer must exhibit high insulation properties and
high resistance to an electrolytic solution. In addition,
the inner layer must exhibit high sealability in order to
hermetically seal the cell case from the outside, i.e. a
thermally-bonded sealed portion between inner layers must
exhibit excellent thermal bonding strength. The inner
layer may be made of a material selected from among a
polyolefin-based resin, such as polypropylene,
polyethylene, polyethylene acrylate, or polybutylene, a
polyurethane resin, and a polyimide resin, which exhibit
excellent chemical resistance and high sealability.
However, the present invention is not limited thereto,
and polypropylene, which exhibits excellent mechanicalphysical
properties, such as tensile strength, rigidity,
12
surface hardness, and resistance to impact strength, and
excellent chemical resistance, is the most preferably
used.
[47] The metal layer, which is disposed so as to abut
the inner layer, corresponds to a barrier layer
configured to prevent moisture or various kinds of gas
from permeating into the battery from the outside.
Aluminum film, which is light and easily shapeable, may
be used as a preferred material for the metal layer.
[48] The outer layer is provided on the other surface
of the metal layer. The outer layer may be made of a
heat-resistant polymer that exhibits excellent tensile
strength, resistance to moisture permeation, and
resistance to air transmission such that the outer layer
exhibits high heat resistance and chemical resistance
while protecting the electrode assembly. As an example,
the outer layer may be made of nylon or polyethylene
terephthalate. However, the present invention is not
limited thereto.
[49] Meanwhile, the pair of electrode leads 110
includes a positive electrode lead and a negative
electrode lead. The positive electrode lead and the
negative electrode lead may be exposed outwards from the
cell case in the state in which positive electrode tabs
and negative electrode tabs of the cell assembly are
13
electrically connected to the positive electrode lead and
the negative electrode lead, respectively, or the
positive electrode lead and the negative electrode lead
may be directly connected to the cell assembly without
electrode tabs. The battery cells correspond to commonly
known constructions, and therefore a more detailed
description thereof will be omitted.
[50] Next, the fire-extinguishing unit 200 will be
described in detail. The fire-extinguishing unit 200
includes a fire-extinguishing pack 210 and a breaking
unit 220. The fire-extinguishing pack 210 may have
defined therein a space configured to receive a fireextinguishing
material, and may be made of at least one
of a polyolefin-based resin, such as polypropylene,
polyethylene, polyethylene acrylate, or polybutylene,
polytetrafluoroethylene, a polyurethane resin, and a
polyimide resin, each of which has a predetermined
thickness that can be torn by the breaking unit 220. In
addition, the fire-extinguishing pack 210 may be located
at one surface or opposite surfaces of each of the
battery cells 100, and may be prismatic, which is similar
to the outer shape of the battery cell 100. However, the
fire-extinguishing pack 210 may be amorphous, whereby the
shape of the fire-extinguishing pack may be freely
changed.
14
[51] A fire-extinguishing material configured to
inhibit an increase in temperature of the battery cells
100 to a predetermined temperature or higher or flames
generated by outbreak of fire is contained in the fireextinguishing
pack 210. At least one of inorganic
carbonate, inorganic phosphate, inorganic sulfate, sodium
bicarbonate, potassium bicarbonate, and ammonium
phosphate monobasic may be used as an example of the
fire-extinguishing material. However, the fireextinguishing
material is not particularly restricted as
long as the fire-extinguishing material is a material
having a fire-extinguishing function.
[52] Here, it is more preferable for the fireextinguishing
material to be liquid such that the fireextinguishing
material can be rapidly discharged,
although the fire-extinguishing material may be powder.
[53] The breaking unit 220 includes a coupling portion
221 fixed to a predetermined part of the battery cell 100
or the fire-extinguishing pack 210 and a blade portion
222 extending from the edge of one side of the coupling
portion 221.
[54] The coupling portion 221 is fixed to the battery
cell 100 or the fire-extinguishing pack 210 in order to
prevent movement of the breaking unit 220. The blade
portion 222 tears or breaks the fire-extinguishing pack
15
210 in order to discharge the fire-extinguishing material
contained therein.
[55] Here, it is preferable for the blade portion 222
to be configured such that the width of the blade portion
(Y-axis direction) gradually decreases with increasing
distance from the coupling portion 221 so as to have a
pointed shape.
[56] Meanwhile, it is preferable for the breaking unit
220 to be made of a shape memory alloy such that the
shape of the blade portion 222 is changed by a
predetermined temperature or higher, which will be
described below in more detail.
[57] The position of the breaking unit 220 is not
particularly restricted as long as the breaking unit 220
comes into tight contact with the fire-extinguishing pack
210. Preferably, the breaking unit 220 is located in the
vicinity of each of the electrode leads 110. More
preferably, two or more breaking units 220 are provided.
The reason for this is that, when heat is generated from
the battery cell 100 due to overcharging, a larger amount
of heat is generated in the vicinity of each of the
electrode leads 110, and therefore it is possible to more
rapidly discharge the fire-extinguishing material in the
case in which two or more breaking units 220 are provided
in the vicinity of each of the electrode leads 110.
16
[58] FIG. 4 is a view illustrating change of the
fire-extinguishing unit based on temperature in the
battery cell according to the first preferred embodiment
of the present invention.
[59] Referring to FIG. 4, the shape of the breaking
unit 220 is changed when the breaking unit is heated to a
predetermined temperature or higher, since the breaking
unit is made of a shape memory alloy, the shape of which
is changed depending on temperature, as previously
described.
[60] That is, when the battery cell 100 is repeatedly
charged and discharged in a normal state, as shown in
FIG. 4, the coupling portion 221 and the blade portion
222 are simply disposed in tight contact between the
battery cell 100 and the fire-extinguishing pack 210.
However, when thermal runaway occurs due to overcharging
and thus the temperature of the battery cell increases to
a predetermined temperature or higher, for example 100°C
or higher, heat is transferred to the breaking unit 220,
whereby the blade portion 222 rises by a predetermined
angle, i.e. the shape of the blade portion is changed.
[61] A portion of the fire-extinguishing pack 210
ruptures as the result of deformation of the blade
portion 222. As a result, the fire-extinguishing
material contained in the fire-extinguishing pack is
17
ejected to control overheating or fire of the battery
cell 100.
[62] Since the breaking unit 220 according to the
present invention is a thin flat plate that is located
between the battery cell 100 and the fire-extinguishing
pack 210 and that is made of a shape memory alloy, which
is deformed depending on temperature, as described above,
a space occupied by the breaking unit is small, unlike a
sensing device configured to sense temperature and
voltage, whereby space utilization is improved, and
therefore it is possible to improve energy density of the
battery module.
[63] Here, the shape memory alloy, of which the
breaking unit 220 is made, may include at least one of a
nickel-titanium (Ni-Ti) alloy, a copper-zinc (Cu-Zn)
alloy, a copper-zinc-aluminum (Cu-Zn-Al) alloy, a coppercadmium
(Cu-Cd) alloy, a nickel-aluminum (Ni-Al) alloy, a
copper-zinc-aluminum (Cu-Zn-Al) alloy, and a copperaluminum-
nickel (Cu-Al-Ni) alloy, the shape of each of
which is changed due to crystal structure change when
heated to a predetermined temperature or higher.
[64] In the case in which the fire-extinguishing pack
210 is located at one side or opposite sides of the
battery cell 100 and the breaking unit 220, which is made
of a shape memory alloy, is located between the battery
18
cell 100 and the fire-extinguishing pack 210, as
described above, the fire-extinguishing material is
discharged from the fire-extinguishing pack 210 when the
temperature of the battery cell 100 abnormally increases,
whereby it is possible to rapidly inhibit outbreak of
fire. In addition, no complicated sensing device or no
installation space is necessary, and therefore it is
possible to simplify a manufacturing process and to
improve energy density.
[65] FIG. 5 is a plan view illustrating breaking
units according to second and third preferred
embodiments of the present invention.
[66] Referring to FIG. 5, (a) of FIG. 5 is a plan
view of the breaking unit 220 according to the second
preferred embodiment of the present invention, wherein
four blade portions 222 are formed along the edge of a
quadrangular coupling portion 221.
[67] In the breaking unit 220 according to the second
embodiment, when thermal runaway occurs in the battery
cell 100 due to overcharging, the four blade portions
222 rise by a predetermined angle to rupture a portion
of the fire-extinguishing pack 220. Consequently, it is
possible to induce rapid discharge of the fireextinguishing
material while reducing the installation
number of the breaking unit 220.
19
[68] In the breaking unit 220 according to the third
embodiment shown in (b) of FIG. 5, two blade portions
222 are formed at one side of a quadrangular coupling
portion 221.
[69] In the breaking unit 220 according to the third
embodiment, when thermal runaway occurs in the battery
cell 100 due to overcharging, the two blade portions 222
rise by a predetermined angle to rupture a portion of
the fire-extinguishing pack 220. Consequently, it is
possible to induce rapid discharge of the fireextinguishing
material while reducing the installation
number of the breaking unit.
[70] Of course, two blade portions 222 according to
the third embodiment may be provided at one side of the
quadrangular coupling portion 221 according to the
second embodiment, the shape of the coupling portion 221
may be polygonal, for example triangular, pentagonal,
hexagonal, or octagonal, or circular, and three or more
blade portions 222 may be formed at the edge of one side
of the coupling portion.
[71] FIG. 6 is a sectional view illustrating breaking
units according to preferred modifications of the
present invention.
[72] Referring to FIG. 6, the breaking unit 220 may
be configured such that a coupling portion 221 and a
20
blade portion 222 extend so as to have the same
thickness, as shown in (a) of FIG. 6. In this case, it
is possible to easily manufacture the breaking unit.
[73] The breaking unit 220 shown in (b) of FIG. 6 is
configured such that a blade portion 222 extending from
a flat coupling portion 221 has a thickness gradually
decreasing with increasing distance from the edge of the
coupling portion 221, specifically the blade portion has
a triangular shape somewhat spaced apart from one side
of the battery cell 100. In this case, the tip end of
the blade portion 222 is very sharp, whereby it is
possible to easily rupture the fire-extinguishing pack
210.
[74] The breaking unit 220 shown in (c) of FIG. 6 is
configured such that a coupling portion 221 and a blade
portion 222 extend so as to have the same thickness, in
the same manner as shown in (a) of FIG. 6, and a
recessed portion 223 having a predetermined depth is
further formed in the portion at which the coupling
portion 221 and the blade portion 222 are connected to
each other. When heat is generated from the battery
cell 100, therefore, the blade portion 222 may be more
sensitively deformed.
[75] The breaking unit 220 shown in (d) of FIG. 6 is
configured such that a blade portion 222 extending from
21
a flat coupling portion 221 has a thickness gradually
decreasing with increasing distance from the edge of the
coupling portion 221, in the same manner as shown in (b)
of FIG. 6, and a recessed portion 223 having a
predetermined depth is formed in the portion at which
the coupling portion 221 and the blade portion 222 are
connected to each other. Consequently, the blade
portion 222 may be easily deformed, as described with
reference to (c) of FIG. 6. Although the recessed
portion 223 is shown as being provided at only one side
of the coupling portion in the figures, one recessed
portion may be provided at each of opposite sides of the
coupling portion.
[76]
[77] Although the specific details of the present
invention have been described in detail, those skilled in
the art will appreciate that the detailed description
thereof discloses only preferred embodiments of the
present invention and thus does not limit the scope of
the present invention. Accordingly, those skilled in the
art will appreciate that various changes and
modifications are possible, without departing from the
category and the technical idea of the present invention,
and it will be obvious that such changes and
modifications fall within the scope of the appended
22
claims.
[78]
[79] (Description of Reference Numerals)
[80] 100: Battery cell
[81] 110: Electrode lead
[82] 200: Fire-extinguishing unit
[83] 210: Fire-extinguishing pack
[84] 220: Breaking unit
[85] 221: Coupling portion
[86] 222: Blade portion
[87] 223: Recessed portion.

【Claim 1】 A battery module having a fireextinguishing
unit, the battery module comprising:
a plurality of battery cells (100) stacked in a
vertical direction or a horizontal direction; and
a fire-extinguishing unit (200) located adjacent to
each of the battery cells (100),
wherein the fire-extinguishing unit (200) comprises
a fire-extinguishing pack (210) containing a fireextinguishing
material and at least one breaking unit
(220) interposed between the battery cell (100) and the
fire-extinguishing pack (210).
【Claim 2】 The battery module according to claim 1,
wherein the fire-extinguishing pack (210) is in tight
contact with one surface or opposite surfaces of the
battery cell (100).
【Claim 3】 The battery module according to claim 1,
wherein the breaking unit (220) comprises: a coupling
portion (221) fixed to the battery cell (100) or the
fire-extinguishing pack (210); and a blade portion (222)
extending from the coupling portion (221), and
wherein the blade portion (222) is made of a shape
24
memory alloy.
【Claim 4】 The battery module according to claim 3,
wherein, when a temperature of the battery cell (100)
increases to a predetermined temperature or higher, the
blade portion (222) is deformed by a predetermined angle
to rupture the fire-extinguishing pack (210).
【Claim 5】 The battery module according to claim 1,
wherein the breaking unit (220) is located adjacent to an
electrode lead (110) of the battery cell (100).
【Claim 6】 The battery module according to claim 3,
wherein the blade portion (222) is provided along an edge
of the coupling portion (221) in plural.
【Claim 7】 The battery module according to claim 3,
wherein the blade portion (222) extends so as to have a
thickness equal to a thickness of the coupling portion
(221).
【Claim 8】 The battery module according to claim 3,
wherein the blade portion (222) has a thickness
gradually decreasing with increasing distance from an
edge of the coupling portion (221).
25
【Claim 9】 The battery module according to claim 7 or
8, wherein a recessed portion (223) is formed in a
portion at which the blade portion (222) and the
coupling portion (221) are connected to each other.
【Claim 10】 A battery pack comprising the battery
module according to any one of claims 1 to 8.