TECHNICAL FIELD
[0002] The present invention relate to a secondary battery.
BACKGROUND ART
[0003] Secondary batteries are rechargeable unlike primarily
batteries, and also, the possibility of compact size and high
15 capacity is high. Thus, recently, many studies on secondary
batteries are being carried out. As technology development
and demands for mobile devices increase, the demands for
secondary batteries as energy sources are rapidly increasing.
[0004] Rechargeable batteries are classified into coin type
20 batteries, cylindrical type batteries, prismatic type
batteries, and pouch type batteries according to a shape of a
battery case. The secondary battery accommodates an electrode
assembly and an electrolyte. In such a secondary battery, an
electrode assembly mounted in a battery case is a chargeable
25 and dischargeable power generating device having a structure
3
in which an electrode and a separator are stacked.
[0005] The electrode assembly may be approximately classified
into a jelly roll type electrode assembly in which a separator
is interposed between a positive electrode and a negative
5 electrode, each of which is provided as the form of a sheet
coated with an active material, and then, the positive
electrode, the separator, and the negative electrode are wound,
a stacked type electrode assembly in which a plurality of
positive and negative electrodes with a separator therebetween
10 are sequentially stacked, and a stack/folding type electrode
assembly in which stacked type unit cells are wound together
with a separation film having a long length.
[0006] A cylindrical battery is constituted by a jelly rolltype electrode assembly and a can containing the electrode
15 assembly.
[0007] The typical cylindrical battery has a risk of being
ignited under various conditions (overcharge, a high
temperature, and an external impact).
[0008] In addition, when the cylindrical battery is ignited,
20 there is a problem that there is no device capable of
extinguishing the fire by itself or preventing the fire from
being spread.

CLAIMS
1. A secondary battery comprising:
an electrode assembly in which electrodes and separators
5 are alternately stacked to be wound;
a can configured to accommodate the electrode assembly
therein, having an opening in an upper end thereof, and
provided with a beading part that is bent inward to form a
recessed groove;
10 a cap assembly seated on the beading part to cover the
opening of the can;
an extinguishing agent accommodated in the recessed
groove to extinguish ignition when the secondary battery is
ignited; and
15 a sealing part configured to seal the recessed groove.
2. The secondary battery of claim 1, wherein the
extinguishing agent is provided as a compressed extinguishing
agent comprising a compressed gas so as to be ejected when the
20 secondary battery is ignited, thereby extinguishing fire in a
surrounding space.
3. The secondary battery of claim 1, wherein the
extinguishing agent is made of at least any one or more of a
25 Halon gas, nitrogen, and carbon dioxide.
22
4. The secondary battery of claim 1, wherein the
sealing part comprises a rubber material.
5 5. The secondary battery of claim 1, wherein the
sealing part is made of an adhesive rubber to adhere to the
can so as to cover the recessed groove.
6. The secondary battery of claim 1, wherein a notch
10 is formed in the beading part of the can.
7. The secondary battery of claim 6, wherein the notch
is formed in at least one surface of an outer surface or an
inner surface of the beading part.
15
8. The secondary battery of claim 6, wherein the can
is formed in a cylindrical shape, and
the notch is formed along the outer surface or the inner
surface of the beading part.
20
9. The secondary battery of claim 6, wherein the notch
is formed in a triangular groove shape.
10. A battery pack comprising the secondary battery of
25 any one of claims 1 to 9.