【TECHNICAL FIELD】
5 Cross Citation with Related Application(s)
This application claims the benefit of Korean Patent Application No. 10-2020-0126271
filed on September 28, 2020 and Korean Patent Application No. 10-2021-0116871 filed on
September 2, 2021 in the Korean Intellectual Property Office, the disclosures of which are
incorporated herein by reference in their entirety.
10 The present disclosure relates to a pouch battery cell and a battery module including the
same, and more particularly to a pouch battery cell that is improved in dimensional stability, delays
a venting phenomenon caused by gas generated inside the battery cell, and prevents electrical
corrosion of the sealing portion, and a battery module including the same.
【BACKGROUND】
15 Along with the increase of technology development and demands for mobile devices, the
demand for batteries as energy sources is increasing rapidly. In particular, a secondary battery has
attracted considerable attention as an energy source for power-driven devices, such as an electric
bicycle, an electric vehicle, and a hybrid electric vehicle, as well as an energy source for mobile
devices, such as a mobile phone, a digital camera, a laptop computer and a wearable device.
20 Based on the shape of a battery case, such a secondary battery is classified into a cylindrical
battery where an electrode assembly is built in a cylindrical metal can, a prismatic battery where
an electrode assembly is built in a prismatic metal can, and a pouch type battery where an electrode
assembly is built in a pouch type case formed of an aluminum laminate sheet. Here, the electrode
assembly built in the battery case is a power generating element, having a structure including a
25 cathode, an anode, and a separator interposed between the cathode and the anode, and capable of
being charged and discharged. The electrode assembly may be classified as a jelly-roll type
electrode assembly configured to have a structure in which a long sheet-type cathode and a long
sheet-type anode, which are coated with active materials, are wound with a separator being
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interposed between the cathode and the anode, and a stacked type electrode assembly configured
to have a structure in which a plurality of cathodes and anodes are sequentially stacked with
separators being interposed between the cathodes and the anodes.
Among them, particularly, a pouch type battery, having a structure in which a stacked type
5 or a stacked/folded type electrode assembly is built in a pouch type battery case formed of an
aluminum laminate sheet, has advantages such as low manufacturing costs, small weight, and easy
shape deformation, and therefore, is gradually increasing in the amount of its usage.
Fig. 1 is a front view showing a conventional pouch battery cell.
Referring to Fig. 1, the pouch battery cell 10 includes a battery case 14 including an upper
10 case 12 and a lower case 13, wherein an electrode assembly (not shown) is built in the upper case
12 and the lower case 13. Further, the upper case 12 and the lower case 13 include a sealing
portion 15 formed by heat-sealing the outer peripheral surfaces of the upper case 12 and the lower
case 13 in order to seal the electrolyte solution contained with the electrode assembly.
Fig. 2 is an enlarged view showing a side portion of the pouch battery cell of Fig. 1. Fig.
15 2(a) is a view before expansion of the battery cell, and Fig. 2(b) is a view after expansion of the
battery cell. Fig. 3 is a diagram showing an expansion region A in which the side portion of the
pouch battery cell of Fig. 1 is expanded.
Referring to Fig. 1, the pouch battery cell 10 is used by being press-bonded to the metal
plate 20 located at both sides of the pouch battery cell 10 when assembling a battery module or
20 battery pack. Referring to Figs. 2 and 3, the pouch battery cell 10 generates a large amount of gas
in the inside of the battery cell during the charging and discharging process, whereby high pressure
is induced inside the sealed case, which causes a swelling phenomenon. The metal plate 20
interrupts the expansion of the pouch battery cell 10 to the upper and lower portions, so that one
side portion of the pouch battery cell 10 can be expanded like the expansion region A.
25 However, referring to Fig. 3, in the case of the conventional pouch battery cell 10, when a
swelling phenomenon occurs in one side portion of the pouch battery cell 10, the one side portion
of the pouch battery cell 10 deviates from the dimensions of the metal plate 20 located at both
sides of the pouch battery cell 10. Thereby, there is a high possibility that the sealing portion 15
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of the pouch battery cell 10 is damaged, which causes a problem that the internal gas is vented to
the outside, and external gas or moisture is flowed into the battery cell, thereby degrading battery
performance.
In addition to this, referring to Fig. 3, the sealing portion 15 is exposed to the outside, and
5 thus, when the pouch battery cell 10 is attached to a battery module (not shown), it may come into
contact with other components. Thereby, when a negative potential is generated during the
charging and discharging process, electrical corrosion occurs in the metal portion exposed to the
sealing portion 15, which causes problems such as the loss of moisture blocking function and the
battery function. Thus, generally, in the prior art, the metal portion exposed from the sealing
10 portion 15 was folded or rolled and thus positioned inside, or a separate tape was attached to the
metal portion. However, in the case of folding or rolling the metal portion exposed from the
sealing portion 15 and thus positioning inside, the sealing portion 15 itself is still exposed on the
outer surface of the battery cell 10, which makes it difficult to completely block the electrical
corrosion generated on the metal portion of the sealing portion 15. Further, when a separate tape
15 is attached to the metal portion, there is a problem that a separate additional process must be
performed.
Therefore, there is a need to develop a pouch battery cell 10 that can delay the venting
phenomenon and prevent electrical corrosion of the sealing portion, while ensuring dimensional
stability against external deformation due to gas generated inside the pouch battery cell 10.

【Claim 1】
A pouch battery cell comprising:
an electrode assembly including a cathode, an anode and a separator interposed between the
5 cathode and the anode; and
a battery case in which the electrode assembly is disposed,
wherein the battery case comprises an upper case, a lower case, and a receiving portion formed
between the upper case and the lower case,
wherein the battery case is formed with sealing portions at which outer peripheral surfaces of
10 the upper case and the lower case are heat-sealed to each other, and
wherein a first end of at least a part of the sealing portions is recessed towards an inside of the
battery case.
【Claim 2】
The pouch battery cell according to claim 1, wherein:
15 a second end of the at least a part of the sealing portions is bent and is disposed adjacent to a
side surface of the upper case or the lower case.
【Claim 3】
The pouch battery cell according to claim 2, wherein:
the second end of the at least a part of the sealing portions is located closer to the electrode
20 assembly than a part of a side surface of the battery case.
【Claim 4】
The pouch battery cell according to claim 1, wherein:
among the sealing portions, the first end of the sealing portion formed on the outer peripheral
surface located at first and second opposite sides of the outer peripheral surface on which an
25 electrode lead of the electrode assembly is formed is recessed towards the inside of the battery
case.
【Claim 5】
The pouch battery cell according to claim 1, wherein:
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among the sealing portions, the first end of a pair of the sealing portions facing each other on
first and second opposite side surfaces of the battery case is recessed towards the inside of the
battery case.
【Claim 6】
5 The pouch battery cell according to claim 5, wherein:
a second end of a pair of the sealing portions is bent and is disposed adjacent to a side surface
of the upper case or the lower case.
【Claim 7】
The pouch battery cell according to claim 6, wherein:
10 the second end of the pair of the sealing portions is located closer to the electrode assembly
than a part of a side surface of the battery case.
【Claim 8】
The pouch battery cell according to claim 5, wherein:
the pair of the sealing portions are respectively formed on the outer peripheral surface located
15 at first and second opposite sides of the outer peripheral surface on which at least one electrode
lead of the electrode assembly is formed.
【Claim 9】
The pouch battery cell according to claim 1, wherein:
the receiving portion comprises a first receiving portion formed in the upper case and a second
20 receiving portion formed in the lower case, and
the first receiving portion and the second receiving portion are together recessed to a
combined length corresponding to the height of the electrode assembly.
【Claim 10】
The pouch battery cell according to claim 1, wherein:
25 the battery case is composed of a pouch type case of a laminated sheet including a resin layer
and a metal layer.
【Claim 11】
The pouch battery cell according to claim 1, wherein:
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the upper case and the lower case have respective shapes that are symmetrical to each other.
【Claim 12】
A battery module comprising the pouch battery cell according to claim 1.
【Claim 13】
5 The battery module according to claim 12,
further comprising a metal plate located on at least one side surface of the pouch battery cell.