Patent Description:
With technological development of mobile devices, such as smartphones, laptop computers, and digital cameras, and an increase in demand therefor, research on secondary batteries, which are capable of being charged and discharged, has been actively conducted. In addition, secondary batteries, which are energy sources substituting for fossil fuels causing air pollution, have been applied to an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (P-HEV), and an energy storage system (ESS).

There are a lithium ion battery, a lithium polymer battery, a nickel-cadmium battery, a nickel-hydride battery, and a nickel-zinc battery as secondary batteries that are widely used at present. The operating voltage of a unit secondary battery cell, i.e. a unit battery cell, is about <NUM>. 0V to <NUM>. When 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 cell module assembly. In addition, cell module assemblies may be connected to each other in series or in parallel to constitute a battery module depending on required output voltage or charge and discharge capacities. In general, a battery pack is manufactured using at least one battery module by adding an additional component.

During use of the battery pack, gas may be generated from the battery cell. Gas may be generated due to exposure to high temperature, internal short circuit, overcharging, or reaction between an electrolyte and an electrode active material caused by repeated charging and discharging.

If the pressure or temperature in the battery cell is increased due to such generation of gas, problems, such as damage to a battery case, internal short circuit, explosion, and fire outbreak, may occur.

In order to prevent these problems, the battery cell may be provided with a structure capable of discharging gas, or a battery module or a battery pack including the battery cell may be provided with a venting device.

In most conventional venting devices, however, emphasis is placed only on discharging of internal gas, and therefore a device capable of rapidly checking whether gas is generated and at the same time automatically discharging the generated gas is required.

Examples of background art can be found in <CIT>, <CIT>, <CIT>, <CIT>, <CIT>. In particular, <CIT> discloses a venting device according to the preamble of claim <NUM>.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a venting device capable of automatically discharging gas depending on internal gas pressure or internal temperature and having an alarm means configured to inform thereof and a battery module including the same.

A venting device according to the present invention to accomplish the above object is a venting device as defined in the independent claim <NUM>. The venting device is configured to be provided at one side of a battery cell or a battery module and configured to discharge gas in the battery cell or the battery module to an outside, the venting device including a gas inlet configured to allow gas in the battery cell or the battery module to be introduced therethrough, a gas outlet configured to allow the gas introduced through the gas inlet to be discharged to the outside therethrough, an alarm means provided at one side of the gas outlet, the alarm means being configured to generate a sound when the gas is discharged to the outside, a connection portion configured to connect the gas inlet and the gas outlet to each other, and a sealing cap located in the connection portion, the sealing cap being configured to automatically discharge gas to the outside, wherein the sealing cap blocks connection between the gas inlet and the gas outlet, thereby blocking discharge of gas and introduction of external air, in a normal state, and moves in the connection portion under a predetermined condition such that the gas inlet and the gas outlet are connected to each other. In use, when an internal temperature is increased to a predetermined level or higher due to gas generated in the battery cell or the battery module, the sealing cap moves in the connection portion such that the gas inlet and the gas outlet are connected to each other. The connection portion is made of a heat shrink tube configured to shrink at a predetermined temperature or higher.

Also, in the venting device according to the present invention, the heat shrink tube may be formed from polyethylene (PE) and polypropylene (PP).

Also, in the venting device according to the present invention, the heat shrink tube may be formed from silicone.

Also, in the venting device according to the present invention, the heat shrink tube may be formed from polyethylene terephthalate (PET).

Also, in the venting device according to the present invention, the sealing cap may include a main body portion and a recessed portion formed at one side of the main body portion such that a part of the main body portion shrinks when the heat shrink tube shrinks.

Also, in the venting device according to the present invention, a part of the heat shrink tube close to the gas inlet may thermally shrink at the lowest temperature.

In addition, a battery cell according to the present invention has the venting device according to the present invention.

In addition, a battery module according to the present invention has the venting device according to the present invention.

A venting device according to an example has an advantage in that a sealing cap configured to be automatically opened and closed depending on gas pressure is provided, whereby it is possible to automatically discharge gas in a battery cell or a battery module when the pressure of the gas is equal to or greater than a predetermined level and to block the introduction of air from the outside when the pressure of the gas is less than the predetermined level.

A venting device according to the claimed invention has an advantage in that a sealing cap configured to be automatically opened and closed depending on temperature is provided, whereby it is possible to automatically discharge gas when the temperature in the battery cell or the battery module is equal to or greater than a predetermined level and to block the introduction of air from the outside when the temperature is less than the predetermined level.

In addition, the venting device according to the present invention has an advantage in that an alarm means is provided, whereby it is possible to check gas discharge in real time.

In addition, the venting device according to the present invention has an advantage in that the venting device is applied to the battery cell or the battery module, whereby it is possible to reduce a danger of explosion or damage due to an increase in internal gas pressure.

Hereinafter, a venting device according to the present invention will be described with reference to the accompanying drawings.

<FIG> is a sectional view schematically showing a venting device according to an exemplary embodiment not being covered by the claimed invention.

When describing the venting device <NUM> with reference to <FIG>, the venting device <NUM> includes a gas inlet <NUM>, a gas outlet <NUM>, a sealing cap <NUM>, a connection portion <NUM>, and an alarm means <NUM>.

The gas inlet <NUM> is a part that has one side coupled to a battery cell or a battery module and serves as a path through which gas is introduced into the venting device <NUM> from the interior thereof, and the gas outlet <NUM> is a part that serves as a path through which the gas introduced from the gas inlet <NUM> is discharged to the outside of the venting device <NUM>. Each of the gas inlet and the gas outlet may generally be configured in the form of a pipe. However, various forms capable of introducing and discharging gas may be employed.

In addition, the connection portion <NUM> is provided between the gas inlet <NUM> and the gas outlet <NUM> so as to connect the gas inlet and the gas outlet to each other, and a protrusion <NUM> configured to space a lower surface of the sealing cap <NUM> and a bottom surface of the connection portion <NUM> apart from each other is provided at a lower end of the connection portion <NUM>.

When describing the positions of the gas inlet <NUM> and the gas outlet <NUM> attached to the connection portion <NUM>, the gas inlet <NUM> is located at a lower end of the connection portion <NUM> while the gas outlet <NUM> is located at about a middle part of the connection portion <NUM> in a direction opposite the gas inlet <NUM>, as shown in <FIG>.

Of course, depending on circumstances, the gas outlet <NUM> may be provided at various positions, such as a direction perpendicular to the gas inlet <NUM>, not the direction opposite the gas inlet <NUM>.

In the connection portion <NUM>, the sealing cap <NUM> movable in the connection portion <NUM> is located. In a normal state, i.e. when the pressure of gas in the battery cell or the battery module is similar to external air pressure, the sealing cap <NUM> is located at the lower end of the connection portion <NUM> to block the flow of gas between the gas inlet <NUM> and the gas outlet <NUM>, as shown in (a) of <FIG>.

When gas is generated in the battery cell and thus gas pressure in the battery cell or the battery module is increased, however, the sealing cap <NUM> is raised in the connection portion <NUM> by the internal gas pressure, as shown in (b) of <FIG>. When the sealing cap is raised higher than the coupling portion with the gas outlet <NUM>, gas introduced from the gas inlet <NUM> may be discharged to the gas outlet <NUM> through the connection portion <NUM>.

Afterwards, when the internal gas pressure is lowered due to discharge of the gas, the sealing cap <NUM> is lowered to the lower end of the connection portion <NUM> to block the discharge of gas and the introduction of air from the outside.

The material for each of the gas inlet <NUM>, the gas outlet <NUM>, the sealing cap <NUM>, and the connection portion <NUM> of the venting device <NUM> may be appropriately selected from among plastics and metals that exhibit high shapeability and heat resistance.

In addition, the alarm means <NUM>, which generates sound at the time of gas discharge to inform of the gas discharge, is provided at the gas outlet <NUM>.

Various known devices that generate sound when gas flows may be used as the alarm means <NUM>, and the alarm means may be appropriately located in the gas outlet <NUM>.

Meanwhile, <FIG> is a view schematically showing a venting device according to an embodiment of the claimed invention.

When describing the venting device <NUM> different in shape and operating mechanism from the venting device <NUM> described above with reference to <FIG>, the venting device <NUM> includes a gas inlet <NUM>, a gas outlet <NUM>, a sealing cap <NUM>, a connection portion <NUM>, and an alarm means <NUM>.

Here, the functions and positions of the gas inlet <NUM> and the gas outlet <NUM> are similar to those of the venting device <NUM> of <FIG>, and therefore a separate description thereof will be omitted.

The connection portion <NUM> has a pipe form configured such that a lower part of the pipe, which is a part connected to the gas inlet <NUM>, is narrow, and the pipe is gradually widened upwards, whereby the pipe has a trapezoidal section, and thereafter the pipe has a constant width.

In addition, the connection portion <NUM> is made of a heat shrink tube <NUM> configured to shrink at a predetermined temperature or higher.

The heat shrink tube <NUM>, which is a tube having characteristics in which the tub shrinks at a predetermined temperature or higher, may be made of various polymer materials, which may be appropriately combined or selected to set the shrink temperature to a desired range.

As the material used in the heat shrink tube <NUM>, various materials, such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), polyvinylchloride (PVC), polytetrafluorethylene (PTFE), and silicone, may be used alone or in a mixed state.

It is preferable for the heat shrink tube <NUM> according to the present invention to be formed including a mixture of polyethylene (PE) and polypropylene (PP), silicone, or PET in consideration of the shrink temperature thereof, etc..

Also, it is preferable for the heat shrink tube <NUM> to be made of a material that shrinks at the lowest temperature at the entirety of the connection portion <NUM> at a part close to the gas inlet <NUM> and a material that shrinks at a higher temperature with an increase in distance from the gas inlet <NUM>.

Meanwhile, the sealing cap <NUM> is located in the connection portion <NUM> made of the heat shrink tube <NUM>.

The sealing cap <NUM> includes a main body portion <NUM> and a recessed portion <NUM> formed in a lower surface of the main body portion <NUM>, and it is preferable for the sealing cap to be made of a heat resistant material that does not shrink even at the temperature at which the heat shrink tube <NUM> shrinks.

It is preferable for the sealing cap <NUM> to have a size corresponding to the inner diameter of the connection portion <NUM> such that the sealing cap is located at a uniform width part of the connection portion <NUM> to block the flow of gas between the gas inlet <NUM> and the gas outlet <NUM>.

In addition, the alarm means <NUM>, which is capable of informing of gas discharge using sound, is attached to the gas outlet <NUM>.

When describing the operating mechanism of the venting device <NUM> having the above construction with reference to <FIG> of <FIG> shows a normal state in which internal temperature is lower than the shrink temperature of the heat shrink tube <NUM>.

In the normal state, the sealing cap <NUM> in the connection portion <NUM> is located immediately above the narrow part of the connection portion <NUM> to block the flow of gas between the gas inlet <NUM> and the gas outlet <NUM>.

When the temperature in the battery cell or the battery module is increased due to generation of gas, however, the heat shrink tube <NUM> made of the lowest shrink temperature material starts to shrink from a lower side thereof, as shown in (b) of <FIG>. As a result, a part of the lower surface of the sealing cap <NUM>, in which the recessed portion <NUM> is formed, shrinks and is pushed upwards to an upper side of the connection portion <NUM>.

When this process is continuously performed, the sealing cap <NUM> is raised to an upper end of the connection portion <NUM>, as shown in (c) of <FIG>. As a result, the gas inlet <NUM> and the gas outlet <NUM> are connected to each other, whereby gas is discharged.

When the internal temperature is lowered as the result of gas discharge, the heat shrink tube <NUM> is relaxed to the original shape thereof. As a result, the sealing cap <NUM> moves downwards to block the flow of air, as shown in (a) of <FIG>.

As described above, the venting device <NUM> or <NUM> according to the present invention blocks the introduction of air from the outside in a normal state and automatically discharges internal gas under a predetermined condition, whereby an effect of preventing explosion, fire outbreak, etc. due to the generation of gas may be achieved, and gas discharge may be checked through sound using the alarm means <NUM> or <NUM>.

The venting device <NUM> or <NUM> may be attached to various battery products, such as a battery pack, in addition to the battery cell or the battery module mentioned above, and the number of venting devices <NUM> or <NUM> to be attached may be appropriately selected as needed.

In addition, two venting devices <NUM> and <NUM> having different operating mechanisms may be simultaneously attached to one battery product.

Claim 1:
A venting device (<NUM>,<NUM>) configured to be provided at one side of a battery cell or a battery module and configured to discharge gas in the battery cell or the battery module to an outside, the venting device (<NUM>,<NUM>) comprising:
a gas inlet (<NUM>,<NUM>) configured to allow gas in the battery cell or the battery module to be introduced therethrough;
a gas outlet (<NUM>,<NUM>) configured to allow the gas introduced through the gas inlet (<NUM>,<NUM>) to be discharged to the outside therethrough;
a connection portion (<NUM>,<NUM>) configured to connect the gas inlet (<NUM>,<NUM>) and the gas outlet (<NUM>,<NUM>) to each other; and
a sealing cap (<NUM>,<NUM>) located in the connection portion (<NUM>,<NUM>), the sealing cap (<NUM>,<NUM>) being configured to automatically discharge gas to the outside, wherein
the sealing cap (<NUM>,<NUM>) blocks connection between the gas inlet (<NUM>,<NUM>) and the gas outlet (<NUM>,<NUM>), thereby blocking discharge of gas and introduction of external air, in a normal state, and moves in the connection portion (<NUM>,<NUM>) under a predetermined condition such that the gas inlet (<NUM>,<NUM>) and the gas outlet (<NUM>,<NUM>) are connected to each other
wherein, in use,
when an internal temperature is increased to a predetermined level or higher due to gas generated in the battery cell or the battery module, the sealing cap (<NUM>) moves in the connection portion (<NUM>) such that the gas inlet (<NUM>) and the gas outlet (<NUM>) are connected to each other,
characterized in that
an alarm means (<NUM>, <NUM>) is provided at one side of the gas outlet (<NUM>, <NUM>), the alarm means (<NUM>, <NUM>) being configured to generate a sound when the gas is discharged to the outside, and in that the connection portion (<NUM>) is made of a heat shrink tube (<NUM>) configured to shrink at a predetermined temperature or higher.