TECHNICAL FIELD
The present application claims priority to Korean Patent Application No. 10-2020-
0147669 filed on November 6, 2020 and Korean Patent Application No. 10-2021-0142441
filed on October 25, 2021 in the Republic of Korea, the disclosures of which are
incorporated herein by reference.
10 The present disclosure relates to a battery cell and a battery module including the
same, and more particularly, to a battery cell with improved external emission of gas
generated inside the battery cell, and a battery module including the same.
BACKGROUND ART
15 As technology development and demand for mobile devices increase, the demand
for secondary batteries as an energy source is rapidly increasing. In particular, secondary
batteries are of great interest as energy sources not only for mobile devices such as mobile
phones, digital cameras, notebooks and wearable devices, but also for power devices such
as electric bicycles, electric vehicles and hybrid electric vehicles.
20 Depending on the shape of a battery case, these secondary batteries are classified
into a cylindrical battery and a prismatic battery in which a battery assembly is included in
a cylindrical or prismatic metal can, and a pouch-type battery in which the battery
assembly is included in a pouch-type case of an aluminum laminate sheet. Here, the
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battery assembly included in the battery case is a power element including a positive
electrode, a negative electrode, and a separator interposed between the positive electrode
and the negative electrode, and capable of charging and discharging, and is classified into a
jelly-roll type in which long sheet-type positive and negative electrodes coated with an
5 active material are wound with a separator being interposed therebetween, and a stack type
in which a plurality of positive and negative electrodes are sequentially stacked with a
separator being interposed therebetween.
Among them, in particular, a pouch-type battery in which a stack-type or
stack/folding-type battery assembly is included in a pouch-type battery case made of an
10 aluminum laminate sheet is being used more and more due to low manufacturing cost,
small weight, and easy deformation.
FIG. 1 is a top view showing a conventional battery cell. FIG. 2 is a crosssectional view, taken along the axis a-a’ of FIG. 1. Referring to FIGS. 1 and 2, a
conventional battery cell 10 includes a battery case 20 having an accommodation portion
15 21 in which a battery assembly 11 is mounted, and a sealing portion 25 formed by sealing
an outer periphery thereof by heat fusion. Here, the battery cell 10 includes an electrode
lead 30 protruding out of the battery case 20 via the sealing portion 25, and a lead film 40
is positioned between upper and lower portions of the electrode lead 30 and the sealing
portion 25.
20 However, as the energy density of the battery cell increases in recent years, there is
a problem that the amount of gas generated inside the battery cell also increases. In the
case of the conventional battery cell 10, a component capable of discharging the gas
generated inside the battery cell is not included, so a venting may occur in the battery cell
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due to gas generation. In addition, moisture may penetrate into the battery cell damaged
by the venting, which may cause side reactions, and there is a problem that battery
performance deteriorates and additional gas is generated. Accordingly, there is an
increasing need to develop a battery cell with improved external emission of gas generated
5 inside the battery cell.
DISCLOSURE
Technical Problem
The present disclosure is designed to solve the problems of the related art, and
10 therefore the present disclosure is directed to providing a battery cell with improved
external emission of gas generated inside the battery cell, and a battery module including
the same.
The object to be solved by the present disclosure is not limited to the abovementioned object, and the objects not mentioned here may be clearly understood by those
15 skilled in the art from this specification and the accompanying drawings.
Technical Solution
In one aspect of the present disclosure, there is provided a battery cell, comprising:
a battery case having an accommodation portion in which a battery assembly is mounted,
20 and a sealing portion formed by sealing an outer periphery thereof by heat fusion; an
electrode lead electrically connected to an electrode tab included in the battery assembly
and protruding out of the battery case via the sealing portion; and a lead film positioned at
a portion corresponding to the sealing portion in at least one of an upper portion and a
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lower portion of the electrode lead, wherein the lead film includes a gas discharge portion
formed to extend from the inside of the battery case to the outside of the battery case, and
the gas discharge portion is opened toward the inside of the battery case.
A front surface and both side surfaces of the gas discharge portion based on a
5 protruding direction of the electrode lead may be closed.
The battery cell may further comprise an inner layer configured to cover at least a
part of a surface of the gas discharge portion.
A material of the inner layer may have a higher melting point compared to a
material of the lead film and may not react with an electrolytic solution.
10 The lead film may comprise a polyolefin-based material, and the inner layer may
contain at least one of polyolefin-based, fluorine-based and porous ceramic-based
materials.
The lead film may have a greater width than the electrode lead.
The lead film may have a greater length than the sealing portion and have a
15 smaller length than the electrode lead.
The gas discharge portion may have a greater width than the electrode lead.
The lead film may include a first lead film and a second lead film, the first lead
film may be positioned at an upper portion of the electrode lead, and the second lead film
may be positioned at a lower portion of the electrode lead.
20 The electrode lead may be positioned between the first lead film and the second
lead film, and the first lead film and the second lead film may be connected to each other.
An end of the gas discharge portion formed within the lead film may be positioned
outer than an outer surface of the battery case.
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An end of the gas discharge portion opened toward the inside of the battery case
may be positioned inner than an inner surface of the battery case.
In another aspect of the present disclosure, there is also provided a battery module,
comprising the battery cell described above.
5
Advantageous Effects
According to the embodiments, since the present disclosure provides a battery cell
including an electrode lead to which a lead film having a maximum penetration area is
attached, and a battery module including the same, it is possible to improve the external
10 emission of gas generated inside the battery cell.
The effect of the present disclosure is not limited to the above effects, and the
effects not mentioned here will be clearly understood by those skilled in the art from this
specification and the accompanying drawings.
15 DESCRIPTION OF DRAWINGS
FIG. 1 is a top view showing a conventional battery cell.
FIG. 2 is a cross-sectional view, taken along the axis a-a’ of FIG. 1.
FIG. 3 is a top view showing a battery cell according to this embodiment.
FIG. 4 is a perspective view showing an electrode lead included in the battery cell
20 of FIG. 3.
FIG. 5 is a cross-sectional view, taken along the axis c-c’ of FIG. 4.
FIG. 6 is a cross-sectional view, taken along the axis d-d’ of FIG. 4.
FIG. 7 is a cross-sectional view, taken along the axis b-b’ of FIG. 3.
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FIG. 8 is a diagram showing the flow of gas generated inside the battery cell of
FIG. 7 and discharged to the outside.
FIG. 9 is a diagram showing a cross section of a battery cell according to
Experimental Example 1.
5 FIG. 10 is a diagram showing a measurement result of a gas pressure in a battery
cell according to Experimental Example 2.
BEST MODE
Hereinafter, with reference to the accompanying drawings, various embodiments
10 of the present disclosure will be described in detail so as to be easily implemented by those
skilled in the art. The present disclosure may be implemented in various different forms
and is not limited to the embodiments described herein.
In order to clearly explain the present disclosure, parts irrelevant to the description
are omitted, and identical or similar components are endowed with the same reference
15 signs throughout the specification.
In addition, since the size and thickness of each component shown in the drawings
are arbitrarily expressed for convenience of description, the present disclosure is not
necessarily limited to the drawings. In order to clearly express various layers and regions
in the drawings, the thicknesses are enlarged. Also, in the drawings, for convenience of
20 explanation, the thickness of some layers and regions is exaggerated.
In addition, throughout the specification, when a part “includes” a certain
component, it means that other components may be further included, rather than excluding
other components, unless otherwise stated.
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In addition, throughout the specification, when referring to “top view”, it means
that the target part is viewed from above, and when referring to “cross-sectional view”, it
means that a vertically-cut section of the target part is viewed from a side.
Hereinafter, a pouch battery cell 100 according to an embodiment of the present
5 disclosure will be described. However, here, the description will be made based on one
side surface of both side surfaces of the pouch battery cell 100, but it is not necessarily
limited thereto, and the same or similar contents may be described in the case of the other
side surface.
FIG. 3 is a top view showing a battery cell according to this embodiment.
10 Referring to FIG. 3, the battery cell 100 according to this embodiment includes a
battery case 200, an electrode lead 300, and a lead film 400.
The battery case 200 includes an accommodation portion 210 in which a battery
assembly 110 is mounted, and a sealing portion 250 formed by sealing an outer periphery
thereof by heat fusion. The battery case 200 may be a laminate sheet including a resin
15 layer and a metal layer. More specifically, the battery case 200 may be made of a
laminate sheet, and may include an outer resin layer forming the outermost layer, a barrier
metal layer preventing penetration of materials, and an inner resin layer for sealing.
Also, the battery assembly 110 may have a structure of a jelly-roll type (winding
type), a stack type (lamination type), or a composite type (stack/folding type). More
20 specifically, the battery assembly 110 may include a positive electrode, a negative
electrode, and a separator disposed therebetween.
Hereinafter, the electrode lead 300 and the lead film 400 will be mainly described.
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FIG. 4 is a perspective view showing an electrode lead included in the battery cell
of FIG. 3.
Referring to FIGS. 3 and 4, the electrode lead 300 is electrically connected to an
electrode tab (not shown) included in the battery assembly 110, and protrudes out of the
5 battery case 200 via the sealing portion 250. In addition, the lead film 400 is positioned
at a portion corresponding to the sealing portion 250 in at least one of an upper portion and
a lower portion of the electrode lead 300. Accordingly, the lead film 400 may improve
the sealing properties of the sealing portion 250 and the electrode lead 300 while
preventing a short circuit from occurring in the electrode lead 300 during thermal fusion.
10 In addition, the lead film 400 may have a greater width than the electrode lead 300.
The lead film may have a greater length than the sealing portion and have a smaller length
than the electrode lead. Accordingly, the lead film 400 may prevent the side surface of
the electrode lead 300 from being exposed to the outside without interfering with the
electrical connection of the electrode lead 300.
15 In addition, the lead film 400 may include a first lead film and a second lead film,
the first lead film may be positioned at an upper portion of the electrode lead 300, and the
second lead film may be positioned at a lower portion of the electrode lead 300. At this
time, the electrode lead 300 may be heat-fused together with the sealing portion 250 in a
state of being located between the first lead film and the second lead film, so that the first
20 lead film and the second lead film may be connected to each other.

WHAT IS CLAIMED IS:
1. A battery cell, comprising:
a battery case having an accommodation portion in which a battery assembly is
5 mounted, and a sealing portion formed by sealing an outer periphery thereof by heat
fusion;
an electrode lead electrically connected to an electrode tab included in the battery
assembly and protruding out of the battery case via the sealing portion; and
a lead film positioned at a portion corresponding to the sealing portion in at least
10 one of an upper portion and a lower portion of the electrode lead,
wherein the lead film includes a gas discharge portion formed to extend from the
inside of the battery case to the outside of the battery case, and
the gas discharge portion is opened toward the inside of the battery case.
15 2. The battery cell according to claim 1,
wherein a front surface and both side surfaces of the gas discharge portion based
on a protruding direction of the electrode lead are closed.
3. The battery cell according to claim 2, further comprising:
20 an inner layer configured to cover at least a part of a surface of the gas discharge
portion.
4. The battery cell according to claim 3,
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wherein a material of the inner layer has a higher melting point compared to a
material of the lead film and does not react with an electrolytic solution.
5. The battery cell according to claim 4,
5 wherein the lead film contains a polyolefin-based material, and
the inner layer contains at least one of polyolefin-based, fluorine-based and porous
ceramic-based materials.
6. The battery cell according to claim 1,
10 wherein the lead film has a greater width than the electrode lead.
7. The battery cell according to claim 6,
wherein the lead film has a greater length than the sealing portion and has a
smaller length than the electrode lead.
15
8. The battery cell according to claim 6,
wherein the gas discharge portion has a greater width than the electrode lead.
9. The battery cell according to claim 1,
20 wherein the lead film includes a first lead film and a second lead film,
the first lead film is positioned at an upper portion of the electrode lead, and
the second lead film is positioned at a lower portion of the electrode lead.
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10. The battery cell according to claim 9,
wherein the electrode lead is positioned between the first lead film and the second
lead film, and the first lead film and the second lead film are connected to each other.
5 11. The battery cell according to claim 1,
wherein an end of the gas discharge portion formed within the lead film is
positioned outer than an outer surface of the battery case.
12. The battery cell according to claim 11,
10 wherein an end of the gas discharge portion opened toward the inside of the
battery case is positioned inner than an inner surface of the battery case.
13. A battery module, comprising the battery cell according to claim 1.