[Technical Field]
This specification claims priority to and the benefit
of Korean Patent Application No. 10-2021-0042363 filed in
the Korean Intellectual Property Office on March 31, 2021,
the entire contents of which are incorporated herein by
reference.
The present invention relates to a battery cell
manufacturing method and a battery cell manufacturing
apparatus.
[Background Art]
A secondary battery that is easy to be applied
according to product groups and has electrical
characteristics, such as high energy density, is generally
applied to an Electric Vehicle (EV) and a Hybrid Electric
Vehicle (HEV) driven by an electric driving source, as well
as portable devices.
The secondary battery is attracting attention as a
new energy source for improving eco-friendliness and energy
efficiency because secondary battery has not only the
primary advantage of dramatically reducing the use of
fossil fuels, but also the advantage that no by-products
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are generated from the use of energy.
The types of secondary batteries currently widely
used include lithium ion batteries, lithium polymer
batteries, nickel cadmium batteries, nickel hydride
batteries, nickel zinc batteries, and the like. The
operating voltage of the unit secondary battery cell is
about 2.5 V to 4.5 V. Therefore, when a higher output
voltage is required, a plurality of battery cells is
connected in series to form a battery pack. In addition,
according to the charge/discharge capacity required for the
battery pack, a plurality of battery cells is connected in
parallel to form a battery pack. Accordingly, the number
of battery cells included in the battery pack and the type
of electrical connection may be variously set according to
a required output voltage and/or charge/discharge capacity.
On the other hand, as types of secondary battery
cells, cylindrical, prismatic, and pouch-type battery cells
are known. The battery cell may be a cylindrical battery
cell. In the battery cell, a separation membrane that is
an insulator is interposed between a positive electrode and
a negative electrode, the positive electrode, the
separation membrane, and the negative electrode are wound
to form an electrode assembly in the form of a jelly roll,
and the electrode assembly is inserted into a battery can
together with an electrolyte to form a battery. In
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addition, a strip-shaped electrode tab may be connected to
an uncoated portion of each of the positive electrode and
the negative electrode, and the electrode tab electrically
connects the electrode assembly and the externally exposed
electrode terminal. For reference, the positive electrode
terminal is a cap plate of a sealing body sealing an
opening of the battery can, and the negative electrode
terminal is the battery can.
However, according to the conventional battery cell
having the foregoing structure, since current is
concentrated in the strip-shaped electrode tab coupled to
the uncoated portion of the positive electrode and/or the
uncoated portion of the negative electrode, there are
problem in that resistance is high, a lot of heat is
generated, and current collection efficiency is not good.
For small cylindrical battery cells with a form
factor of 18650 or 21700, resistance and heat are not a big
issue. However, when the form factor is increased in order
to apply the cylindrical battery cell to an electric
vehicle, a problem may arise in that the cylindrical
battery cell ignites as a lot of heat is generated around
the electrode tab during the rapid charging process.
[Detailed Description of the Invention]
[Technical Problem]
The present invention is to provide a battery cell
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manufacturing method and a battery cell manufacturing
apparatus in which safety problems, such as ignition due to
gas generation, are alleviated.
[Technical Solution]
An exemplary embodiment of the present invention
provides a battery cell manufacturing method including: (A)
disposing a battery can which accommodates an electrode
assembly and an electrolyte and has an opening at one side
within an exhaust chamber, or coupling the exhaust chamber
to the opening so as to seal the opening; (B) adjusting the
exhaust chamber to an inert atmosphere; and (C) performing
a pre-charge on the electrode assembly and discharging
exhaust gas generated due to the pre-charge through the
exhaust chamber.
An exemplary embodiment of the present invention
provides a battery cell manufacturing apparatus including
an exhaust chamber in which a battery can which
accommodates an electrode assembly and an electrolyte and
has an opening at one side is disposed or which is coupled
so as to seal the opening.
[Advantageous Effects]
In the case of the battery cell manufacturing method,
since the pre-charge is performed after the assembly of the
battery cell is completed and before the activation process
is performed, an operation of discharging the gas generated
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in this process is not performed.
The battery cell with improved capacity and/or output
has an increased size compared to the 21700 cylindrical
cell, so that the amount of gas generated during charging
increases by approximately 2.5 to 3.5 times based on the
volume compared to the existing case, and as a result, if
gas discharge does not proceed together in the pre-charge
process, the battery cell may be vulnerable to safety. For
this reason, a facility/process capable of discharging gas
during charging is required.
According to one aspect of the present invention, it
is possible to discharge exhaust gas generated during the
pre-charge through the opening and the exhaust chamber by
disposing the battery can which accommodates the electrode
assembly and the electrolyte and has the opening at one
side within the exhaust chamber or coupling the exhaust
chamber to the opening so as to seal the opening.
Therefore, even if the amount of gas generated during the
pre-charge of the battery cell with improved capacity
and/or output is significantly increased compared to the
existing case, the process proceeds while smoothly
discharging the gas during the pre-charge process, thereby
solving the safety problem.