Patent Description:
Recently, there has been a rapid increase in the demand for portable electronic products such as laptop computers, video cameras and mobile phones, and with the widespread use of robots and electric vehicles, many studies are being made on high performance secondary batteries that can be repeatedly recharged.

Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, lithium secondary batteries and the like. In particular, lithium secondary batteries have little or no memory effect, and thus they are gaining more attention than nickel-based secondary batteries for their advantages that recharging can be done whenever it is convenient, the self-discharge rate is very low and the energy density is high.

An individual secondary battery may be used, but in many cases, a plurality of secondary batteries electrically connected in series and/or in parallel may be used. In particular, the electrically connected secondary batteries may form a battery module when received in a module case. Additionally, the battery module may be individually used, or at least two battery modules may be electrically connected in series and/or in parallel to form a device of higher level such as a battery pack.

As electricity shortage or eco-friendly energy issues arise in recent years, much attention is directed to Energy Storage Systems (ESSs) for storing power after the power is produced. Typically, using the energy storage systems, it is easy to build smart grid systems, which makes it possible to easily control the power supply in specific regions or cities.

Battery packs used in energy storage systems may need much higher capacity than medium and small-sized battery packs. Accordingly, in general, the battery pack include a plurality of battery modules. Additionally, to increase the energy density, in many cases, the plurality of battery modules is densely arranged in a very narrow space.

However, when the plurality of battery modules is densely arranged in the narrow space, they may be vulnerable to fires. For example, when thermal runaway occurs in any one battery module, high temperature gas may be vented from at least one battery cell. Furthermore, when the gas is vented, high temperature spark may be vented, and the spark may include active materials separated from the electrode in the battery cell or molten aluminum particles. When the high temperature spark and the high temperature gas meets oxygen, a fire may occur in the battery pack.

In particular, when the fire occurs in the specific battery cell or module, the fire may spread to the neighboring battery cell or battery module or another battery pack. In particular, since the energy storage system includes the plurality of batteries densely arranged in the narrow space, when the fire occurs, it is not easy to stop the fire. Furthermore, when considering the scale or role of the energy storage system, the fire in the battery pack may cause very grave economical damage and loss of human life. Therefore, it is necessary to prevent the fire propagation in the event of thermal runaway. <CIT> discloses a battery pack according to the preamble of claim <NUM>.

The present disclosure is designed to solve the above-described problem, and therefore the present disclosure is directed to providing a battery pack configured to prevent a fire from occurring in surrounding structures of the battery pack or another battery pack when high temperature gas or spark is generated from any battery module due to thermal runaway and an energy storage system comprising the same.

The technical problem of the present disclosure to be solved is not limited to the above-described problem, and these and other problems will be clearly understood by those skilled in the art from the following detailed description.

To achieve the above-described objective, a battery pack according to claim <NUM> is provided.

The mesh may include an entrance mesh and an exit mesh to cover the entrance and the exit of the temperature reducing tunnel, respectively.

The temperature reducing tunnel may include a plurality of gas movement passages extended in a lattice structure between the entrance mesh and the exit mesh.

Each hole of the entrance mesh or the exit mesh may be smaller than a cross-sectional size of each gas movement passage.

Each gas movement passage may include a plurality of partitions, the plurality of partitions may include upper partitions extending obliquely from a ceiling surface of the gas movement passage and spaced apart from each other, and lower partitions alternately disposed with the upper partitions and extending obliquely from a bottom surface of the gas movement passage.

The anti-fire venting unit may be detachably attached to a case hole in a wall of the pack case, the case hole forming an exit of the gas venting path.

The anti-fire venting unit may be provided plurally and the plurality of anti-fire venting units may be arranged at a predetermined interval along the gas venting path inside the pack case.

The anti-fire venting unit may be disposed on the gas venting path corresponding to between any one battery module and its neighboring battery module.

The anti-fire venting unit further includes an outer frame with a hollow structure whereby the temperature reducing tunnel is interference fit therein.

The outer frame may have two openings, each one opening on each of a side and an opposite side, and the mesh may be integrally fixed and coupled to one of the two openings, and rotatably coupled to the other opening.

The outer frame may be fixed and coupled to an inside of the pack case.

The at least one battery module may include two or more battery modules arranged consecutively, and the battery pack may further include a heat transfer suppression unit between the neighboring battery modules to suppress heat transfer between the battery modules.

The heat transfer suppression unit may include a first thermal insulation pad, a first thermally conductive sheet made of a metal, a second thermal insulation pad, a second thermally conductive sheet made of a metal and a third thermal insulation pad, stacked in a direction in that order, and the first thermally conductive sheet and the second thermally conductive sheet may be in surface contact with an upper surface of the pack case.

According to another aspect of the present disclosure, there is provided an energy storage system including the battery pack.

According to the present disclosure, when high temperature venting gas and spark occurs due to thermal runaway of the battery module, it is possible to prevent fires from occurring in the external structures near the battery pack or another battery pack.

Specifically, according to the configuration of the anti-fire venting unit according to the present disclosure, venting gas may be allowed to flow out of the pack case after its temperature is reduced, and high temperature spark may be filtered to prevent it from coming out of the battery pack. Accordingly, it is possible to prevent fires from occurring in the surrounding structures of the battery pack or another battery pack.

The present disclosure may have any other effects, and these and other effects will be described in each embodiment or a description of the effects that can be easily inferred by those skilled in the art is omitted.

Hereinafter, the exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

Therefore, the embodiments described herein and the illustrations shown in the drawings are just an exemplary embodiment of the present disclosure, but not intended to fully describe the technical aspects of the present disclosure, so it should be understood that a variety of other equivalents and modifications could have been made thereto at the time that the application was filed.

<FIG> is a diagram schematically showing the main parts of a battery pack according to an embodiment of the present disclosure, <FIG> is an exploded perspective view of an anti-fire venting unit of <FIG>, and <FIG> is a cross-sectional view of the anti-fire venting unit of <FIG>.

Referring to <FIG>, the battery pack <NUM> according to an embodiment of the present disclosure includes a battery module <NUM>, a pack case <NUM> and the anti-fire venting unit <NUM>.

The battery module <NUM> may include at least one secondary battery <NUM> to store and supply energy. Additionally, the battery pack <NUM> may include at least one battery module <NUM>. In particular, to improve the capacity and/or output of the battery pack <NUM>, the battery pack <NUM> may include a plurality of battery modules <NUM> as shown in <FIG>. In this instance, the plurality of battery modules <NUM> may be arranged in at least one direction.

Although not shown, in addition to the secondary batteries <NUM>, the battery module <NUM> may include components for electrically connecting the secondary batteries <NUM>, components for sensing voltage and temperature, a circuit board, a connector and a module housing accommodating them.

The secondary battery <NUM> may be a pouch-type secondary battery <NUM> including an electrode assembly, an electrolyte solution and a pouch-type case.

For example, the plurality of pouch-type secondary batteries <NUM> may be stacked in the horizontal direction (X axis direction) upright in the vertical direction (Z axis direction) to form a cell stack, which is received in the module housing. In this instance, electrode leads of each pouch-type secondary battery <NUM> may directly contact each other or may be electrically connected through a busbar.

The secondary battery <NUM> may include any other type of secondary battery than the pouch-type, for example, a cylindrical or prismatic secondary battery including a battery case of a metal can.

The module housing may be configured to receive at least one secondary battery <NUM> in the internal space.

For example, the module housing may include a rectangular pipe-shaped housing frame including an upper plate, a lower plate and two side plates. Some plates included in the housing frame, for example, the lower plate and the two side plates may be integrated into one. In this case, the integrated shape of the lower plate and the two side plates may be an approximately U shape.

The cell stack is housed in the limited internal space of the housing frame, and the secondary battery <NUM> cells are electrically connected to each other. In this instance, all the secondary battery <NUM> cells may be connected in series or in parallel by welding the electrode leads of the neighboring secondary battery <NUM> cells to one busbar. Here, the busbar refers to a metal bar-shaped conductor.

A front cover and a rear cover may be mounted in the welded part of the electrode leads of the secondary battery <NUM> cells and the busbar, i.e., on the front side and the rear side of the housing frame, respectively. The front cover and the rear cover may be made of an insulation material, for example, a plastic material to prevent a short circuit from occurring in the electrically connected part. Additionally, the front cover or the rear cover may be used as an installation location of an external terminal of the module and a connector.

The pack case <NUM> is the component used to receive the plurality of battery modules <NUM> and may be formed with a hermetic structure using a material having high mechanical strength to protect the plurality of battery modules <NUM> from external physical and chemical factors. Although <FIG> schematically shows the pack case <NUM> of a box shape with approximately rectangular prism for simplicity of illustration, the pack case <NUM> may include a plate-shaped upper cover <NUM> that forms a top surface and a plate-shaped lower cover <NUM> that forms a bottom surface and walls, and the upper cover <NUM> and the lower cover <NUM> may be coupled and sealed by bolting, hooking, sealing and adhesion.

Additionally, the pack case <NUM> has a case hole <NUM> (see <FIG>). The case hole <NUM> may be on one side of the pack case <NUM>, for example, in the wall of the lower cover <NUM>. The case hole <NUM> may be open at an area of the wall to allow air to pass through the pack case <NUM> so the air may move in and out of the pack case <NUM>.

The case hole <NUM> may prevent the deformation of the pack case <NUM> by removing a pressure difference between the inside and outside of the battery pack <NUM>, and may act as a gas outlet through which venting gas exits the battery pack <NUM> when the venting gas occurs in any battery module <NUM> within the battery pack <NUM>. The case hole <NUM> may be an exit of a gas venting path, i.e., an end of the gas venting path for guiding the release of the venting gas occurred in the battery module <NUM> from the pack case <NUM>.

The anti-fire venting unit <NUM> is a structure that does not allow flames, sparks and impurities to pass through and allows venting gas to pass through to reduce the temperature of the venting gas. The anti-fire venting unit <NUM> of this embodiment may be detachably attached to the case hole <NUM>. For example, the anti-fire venting unit <NUM> may cover the case hole <NUM> and may be attached to the outer wall of the pack case <NUM>. Although not shown, bolts and sealing agents may be used to ensure adequate fixing and sealability between the anti-fire venting unit <NUM> and the pack case <NUM>.

Specifically, as shown in <FIG> and <FIG>, the anti-fire venting unit <NUM> includes a temperature reducing tunnel <NUM> made of a metal having pores and two meshes <NUM>.

The temperature reducing tunnel <NUM> may include a plurality of gas movement passages <NUM> made of a metal having high thermal conductivity and high strength such as, for example, aluminum, and the gas movement passages <NUM> may be extended in a lattice structure. Additionally, the meshes <NUM> may cover the entrance and exit of the temperature reducing tunnel <NUM>.

While high temperature venting gas passes through the temperature reducing tunnel <NUM>, heat is absorbed by the body of the temperature reducing tunnel <NUM>, so the temperature becomes lower. In particular, the porous structure of the temperature reducing tunnel <NUM> made of the metal increases the contact area between the venting gas and the temperature reducing tunnel <NUM>, resulting in the increased amount of thermal radiation of the venting gas.

Additionally, when the venting gas passes through the plurality of narrow gas movement passages <NUM> of this embodiment, the venting gas increases in pressure and speed. The convective heat transfer coefficient is proportional to the air flow rate. Accordingly, as the energy loss of the venting gas increases with the increasing pressure and the convective heat transfer rate increases with the increasing flow rate, a temperature difference of the venting gas before and after the venting gas passes through the temperature reducing tunnel <NUM> significantly increases. Accordingly, in the event of high temperature venting gas in the battery pack <NUM>, when the venting gas exits the battery pack <NUM> through the temperature reducing tunnel <NUM>, the temperature becomes lower, so the venting gas does not act as the factor that causes a fire to the structure outside of the battery pack <NUM> or the other battery pack <NUM>. Additionally, flames may be restrained from moving or extinguished due to trapping in the plurality of narrow gas movement passages <NUM> of the temperature reducing tunnel <NUM>.

In a variation, each gas movement passage <NUM> of the temperature reducing tunnel <NUM> may further include a plurality of partitions <NUM>,<NUM> to promote a turbulent flow in each gas movement passage <NUM>.

For example, as shown in <FIG>, the plurality of partitions may include upper partitions <NUM> and lower partitions <NUM>, the upper partitions <NUM> may be spaced apart from each other, each upper partition <NUM> may extend obliquely from the ceiling surface of the gas movement passage <NUM>, and the lower partitions <NUM> may be alternately disposed with the upper partitions <NUM> and each extend obliquely from the bottom surface of the gas movement passage <NUM>.

According to the internal structure of the gas movement passages <NUM>, although <FIG> shows the flow of venting gas in only one gas movement passage <NUM> for simplicity of illustration, the turbulent flow is remarkably generated while the venting gas passes through the narrow gas movement passages <NUM>. Accordingly, the loss of heat from the venting gas to the temperature reducing tunnel <NUM>, i.e., the convective heat transfer rate further increases. Accordingly, the temperature reducing tunnel <NUM> according to this variation may be more advantageous in reducing the temperature of the venting gas.

The meshes <NUM> are the component used to block high temperature spark that may move with the venting gas, and include the entrance mesh 320a and the exit mesh 320b to cover the entrance and exit of the temperature reducing tunnel <NUM>, respectively. Here, the spark refers to active materials separated from the electrode in the secondary battery <NUM> or molten aluminum particles. When the venting gas is released into the atmosphere, the emission of unfiltered high temperature spark from the battery pack <NUM> significantly increases the risk of fires in the surrounding structures of the battery pack <NUM> or the other battery pack <NUM>.

Some of the conventional battery packs <NUM> use meshes to prevent the ingress of impurities or the emission of sparks. However, in many cases, the meshes are damaged, for example, distorted or torn open, due to the pressure of the venting gas when vented. The present disclosure couples the meshes <NUM> to the entrance and exit of the temperature reducing tunnel <NUM> to prevent the meshes <NUM> from being damaged by the strong pressure of the venting gas when vented.

For example, as the meshes <NUM> are coupled to the entrance and exit of the temperature reducing tunnel <NUM> as shown in <FIG> and <FIG>, the entire area of the meshes <NUM> may be supported by the temperature reducing tunnel <NUM> which is a metal structure, thereby avoiding distortion or perforation under the pressure of the venting gas.

Each hole in the mesh of the entrance mesh 320a and the exit mesh 320b may be much smaller than the cross-sectional size (air hole size) of the gas movement passages <NUM> of the temperature reducing tunnel <NUM>. Accordingly, ordinary spark particles, not in ultrasmall size, are not allowed to pass through the entrance mesh 320a or the exit mesh 320b. The meshes <NUM> may be made of a metal or a fire resistant material (for example, mica) that does not easily melt in heat when exposed to high temperature by the contact with the high temperature spark.

Accordingly, according to the anti-fire venting unit <NUM> of this embodiment as described above, it is possible to allow venting gas out after reducing the temperature while preventing the emission of high temperature spark in the event of high temperature venting gas in the battery pack <NUM>, thereby preventing fires in the surrounding structures of the battery pack <NUM> or the other battery pack <NUM>.

Subsequently, a battery pack <NUM> according to another embodiment of the present disclosure will be described with reference to <FIG>.

<FIG> is a diagram schematically showing the main parts of the battery pack <NUM> according to another embodiment of the present disclosure, <FIG> is a diagram showing battery modules <NUM> and a heat transfer suppression unit <NUM> of <FIG>, <FIG> is a diagram showing the heat insulation and heat dissipation structure between the battery modules <NUM> of the battery pack <NUM> according to another embodiment of the present disclosure, and <FIG> is a perspective view showing an anti-fire venting unit 300A of <FIG>.

The same reference numeral as the previous embodiment indicates the same element. To avoid redundancy, the overlapping description of the same element is omitted and the following description is made based on difference(s) between this embodiment and the previous embodiment.

The battery pack <NUM> according to another embodiment of the present disclosure includes a plurality of anti-fire venting units 300A arranged at a predetermined interval along the gas venting path inside the pack case <NUM>, and further includes the heat transfer suppression unit <NUM> to suppress the movement of heat between the battery modules <NUM>.

Describing the heat transfer suppression unit <NUM>, the heat transfer suppression unit <NUM> is the component used to prevent the spread of heat to the adjacent battery module <NUM> in the event of thermal runaway of any one battery module <NUM>, and may include a first thermal insulation pad <NUM>, a first thermally conductive sheet <NUM>, a second thermal insulation pad <NUM>, a second thermally conductive sheet <NUM> and a third thermal insulation pad <NUM>, stacked in a direction (X axis direction) in that order. As shown in <FIG> and <FIG>, the plurality of battery modules <NUM> may be continuously arranged side by side in the X axis direction, and each one heat transfer suppression unit <NUM> may be positioned between the two adjacent battery modules <NUM>.

Each of the first thermal insulation pad <NUM>, the second thermal insulation pad <NUM> and the third thermal insulation pad <NUM> may be a foam with a porous structure, a pad made of ceramic fibers or a film, and may come in various sizes and shapes as necessary. This embodiment shows the second thermal insulation pad <NUM> divided into two unit second thermal insulation pads 430a, 430b, but this is provided for illustration purposes, and one second thermal insulation pad <NUM> or three or more second thermal insulation pads <NUM> may be contemplated.

Additionally, each of the first thermally conductive sheet <NUM> and the second thermally conductive sheet <NUM> may be a thin film made of a material having high thermal conductivity such as, for example, aluminum or graphite.

Specifically, as shown in <FIG>, the first thermal insulation pad <NUM> may be configured to cover the side of the left battery module <NUM> and part of the upper surface, the first thermally conductive sheet <NUM> may have the upper end bent to conform the first thermal insulation pad <NUM>, and the upper end surface of the first thermally conductive sheet <NUM> may be configured to contact the upper cover <NUM> of the pack case <NUM>, i.e., the upper surface of the pack case <NUM>.

Additionally, the third thermal insulation pad <NUM> and the second thermally conductive sheet <NUM> may be symmetric to the first thermal insulation pad <NUM> and the first thermally conductive sheet <NUM> with respect to the second thermal insulation pad <NUM>, respectively, and may be configured to cover the side of the right battery module <NUM> and part of the upper surface.

According to the above-described configuration, in the event of thermal runaway of the left battery module <NUM> shown in <FIG>, heat from the left battery module <NUM> is transferred to the right battery module <NUM> through five stages (primary heat insulation > primary thermal dispersion > secondary heat insulation > secondary thermal dispersion > tertiary heat insulation). That is, the heat is blocked by the first thermal insulation pad <NUM>, and the heat transferred from the first thermal insulation pad <NUM> is conducted to the pack case <NUM> through the first thermally conductive sheet <NUM>. That is, the heat from the first thermally conductive sheet <NUM> is transferred to the pack case <NUM> having much higher thermal capacity. Additionally, the heat from the first thermally conductive sheet <NUM> is blocked by the second thermal insulation pad <NUM>, and the heat transferred from the second thermal insulation pad <NUM> is transferred to the pack case <NUM> through the second thermally conductive sheet <NUM> and blocked by the third thermal insulation pad <NUM>. Accordingly, as most of the heat is blocked or released into the atmosphere through the five stages, the amount of heat transferred from the left battery module <NUM> to the right battery module <NUM> is very small.

Additionally, the battery pack <NUM> according to another embodiment of the present disclosure may include the battery modules <NUM>, each surrounded by the anti-fire venting units 300A, the heat transfer suppression unit <NUM> and the pack case <NUM>, to allow venting gas to flow along the specific path in the pack case <NUM> in the event of the venting gas in the battery module <NUM>.

For example, as shown in <FIG>, the gas venting path may be designed such that the top and bottom of the second thermal insulation pad <NUM> contact the upper surface and the lower surface of the pack case <NUM>, respectively, and the rear end (a narrow surface placed vertically) of the second thermal insulation pad <NUM> contacts the wall of one side of the pack case <NUM> to stop the venting gas from flowing to the top (+Z axis direction), the bottom (-Z axis direction), the two sides (±X axis direction) and the rear side (+Y axis direction) of each battery module <NUM> and allow the venting gas to flow to the front side (-Y axis direction), move in the -X axis direction along one edge of the pack case <NUM> and exit the case hole <NUM>. In this instance, a barrier W may be added to shield the side of the outermost battery module <NUM> that does not contact the other battery module <NUM>.

Additionally, the anti-fire venting units 300A according to another embodiment of the present disclosure may be arranged at the predetermined interval along the gas venting path.

Preferably, to prevent the spread of high temperature spark to the other battery module <NUM> in the event of venting gas and spark in any battery module <NUM>, each anti-fire venting unit 300A may be disposed on the gas venting path corresponding to between any one battery module <NUM> and its adjacent battery module <NUM>.

In this instance, one side of the anti-fire venting unit 300A may contact the front surface of the second thermal insulation pad <NUM> and the upper surface, the lower surface and the other side of the anti-fire venting unit 300A may contact the upper surface, the lower surface and the -Y axis direction wall of the pack case <NUM>, respectively, or may be covered with them, to allow the venting gas to exit the case hole <NUM> through the anti-fire venting unit 300A in the event of the venting gas in the battery module <NUM>.

As shown in <FIG> and <FIG>, the anti-fire venting unit 300A according to another embodiment of the present disclosure may include the temperature reducing tunnel <NUM>, the entrance mesh 320a, the exit mesh 320b and an outer frame <NUM>.

That is, when compared with the previous embodiment, the anti-fire venting unit 300A of this embodiment further includes the outer frame <NUM> fixed and coupled to the inside of the pack case <NUM>.

As shown in <FIG>, the outer frame <NUM> has a hollow structure with two openings, each one opening on each of one side and the other side, and the temperature reducing tunnel <NUM> is interference fit in the outer frame <NUM> through the openings. The outer frame <NUM> plays a role in protecting the temperature reducing tunnel <NUM> from external impacts. Additionally, the anti-fire venting unit 300A may be fixed to the inside of the pack case <NUM> by coupling brackets (not shown) to the outer side of the outer frame or integrally forming them and connecting the bracket and the pack case <NUM> with bolts.

Additionally, the meshes <NUM> may be attached to the two openings of the outer frame <NUM> by any one of bolting, welding and adhesion methods.

In another variation, the meshes <NUM> may be integrally fixed and coupled to one of the two openings of the outer frame <NUM> and rotatably coupled to the other opening. For example, as shown in <FIG>, the upper end of one opening of the outer frame <NUM> and the upper end of the mesh <NUM> may be connected with hinges <NUM> and the mesh <NUM> may be lifted up to receive the temperature reducing tunnel <NUM> in the outer frame <NUM>. Additionally, after the temperature reducing tunnel <NUM> is received in the outer frame <NUM>, lockers <NUM> at the lower end of one opening of the outer frame <NUM> may be fit in lock holes <NUM> at the lower end of the mesh <NUM>. In this case, the assembly process of the mesh <NUM> and the outer frame <NUM> is more straightforward than the process using bolting, welding and adhesion, so it is possible to perform a rework task more easily when it is necessary to replace or repair the temperature reducing tunnel <NUM> or the mesh <NUM> afterwards.

<FIG> is a diagram schematically showing the main parts of a battery pack <NUM> according to still another embodiment of the present disclosure.

When compared with the battery pack <NUM> of the previous embodiment, the battery pack <NUM> according to still another embodiment of the present disclosure includes the gas venting paths at the two side edges in the pack case <NUM> and the anti-fire venting units 300A in each gas venting path.

As shown in <FIG>, in this embodiment, when venting gas occurs in the battery module <NUM>, the venting gas is allowed to flow out from the front side (-Y axis direction) and the rear side (+Y axis direction) of the battery module <NUM> and move along the two side edges of the pack case <NUM>, so the venting gas may be released into the atmosphere faster than the previous embodiment. Accordingly, the battery pack <NUM> according to this embodiment may be effective in suppressing the fire propagation.

An energy storage system according to the present disclosure may include at least one battery pack according to the present disclosure. In particular, the energy storage system may include a plurality of battery packs according to the present disclosure electrically connected to each other to have high energy capacity. Besides, the energy storage system according to the present disclosure may further include a variety of different components of energy storage systems known at the time the application was filed. Furthermore, the energy storage system may be used at various locations or devices, for example, smart grid systems or electrical power charging stations.

Meanwhile, the terms indicating directions as used herein such as upper, lower, left, right, front and rear are used for convenience of description only, and it is obvious to those skilled in the art that the term may change depending on the position of the stated element or an observer.

Claim 1:
A battery pack (<NUM>, <NUM>, <NUM>), comprising:
at least one battery module (<NUM>);
a pack case (<NUM>) accommodating the battery module (<NUM>); and
an anti-fire venting unit (<NUM>, 300A) positioned on a gas venting path configured to guide gas generated from the battery module (<NUM>) to flow out of the pack case (<NUM>),
wherein the anti-fire venting unit (<NUM>, 300A) includes:
a temperature reducing tunnel (<NUM>); and
a mesh (<NUM>) configured to cover at least one of an entrance or an exit of the temperature reducing tunnel (<NUM>),
characterized in that
the temperature reducing tunnel (<NUM>) is made of metal having pores, and
the anti-fire venting unit (<NUM>, 300A) further includes an outer frame (<NUM>) with a hollow structure whereby the temperature reducing tunnel (<NUM>) is received therein.