Patent Description:
Recently, with the rapid increase in demand for portable electronic products such as laptop computers, video cameras and mobile phones and the extensive development of electric vehicles, accumulators for energy storage, robots and satellites, 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, and among them, 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.

These lithium secondary battery mainly uses lithium-based oxide and carbon material as a positive electrode active material and a negative electrode active material, respectively. In addition, this lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate respectively coated with the positive electrode active material and the negative electrode active material are disposed with a separator interposed therebetween, and an exterior, namely a battery case, for hermetically accommodating the electrode assembly together with an electrolyte.

In addition, depending on the shape of the exterior, lithium secondary batteries may be classified into a can-type secondary battery in which the electrode assembly is included in a metal can and a pouch-type secondary battery in which the electrode assembly is included in a pouch made of an aluminum laminate sheet.

In particular, the demand for large-capacity battery modules applied to electric vehicles and the like is increasing recently. The large-capacity battery module includes a plurality of battery cells, and thus, when a fire or explosion occurs in some of the plurality of battery cells, flames and high-temperature gas are discharged to increase the temperature of other adjacent battery cells, which may propagate fire or thermal runaway, leading to a secondary explosion. Accordingly, there is a need for a method to increase the stability against fire or gas explosion of the battery module.

Examples of background art can be found in <CIT> and <CIT>.

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing a battery module with enhanced stability against fire and explosion, a battery pack comprising the same and a vehicle.

In accordance with the independent claim <NUM>, there is provided a battery module, comprising:.

Also, the screen member may include a heat-resistant sheet provided in close contact with an outer surface of the cell frame to seal the exposure hole and configured such that a portion thereof facing the exposure hole is raptured by the gas pressure to open the exposure hole, and
the protection plate may be located at an outer side of the heat-resistant sheet so that the heat-resistant sheet is fixed to the outer surface of the cell frame.

In addition, the protection plate may include a rib protruding outward from an outer circumference of the communication hole.

Further, the protection plate may further include a perforating needle configured to perforate a part of the heat-resistant sheet when a portion of the heat-resistant sheet facing the exposure hole expands by the gas pressure.

Also, the heat-resistant sheet may include a rupture portion formed to have a relatively smaller sheet thickness than other portion.

Moreover, the screen member may further include an adhesive sheet attached to the protection plate to seal the communication hole and configured to be detached from the protection plate by an explosion pressure when the battery cell explodes.

In addition, the screen member may include a heat-resistant film coated in the exposure hole to seal the exposure hole.

Further, the battery module may further comprise a module case having an inner space configured to accommodate the cell frame, and a staying space formed between an outer wall thereof and the cell frame spaced apart from each other to temporarily accommodate gas discharged from the battery cell and configured to communicate with the communication hole.

In addition, to achieve the above-described object, a battery pack of the present disclosure includes at least one battery module.

Further, to achieve the above-described object, a vehicle of the present disclosure includes at least one battery module.

According to an embodiment of the present disclosure, since the present disclosure includes the screen member configured to seal the exposure hole and to open the exposure hole by gas pressure and the protection plate configured to fix the screen member, the gas generated inside the cell frame may be discharged to the outside through the open exposure hole and the communication hole. Since the gas discharged to the outside of the cell frame is not able to flow into other exposure holes sealed by the screen member, it is possible to effectively prevent fire or thermal runaway from propagating to other battery cells adjacent to the battery cell where the fire or thermal runaway has occurred. Accordingly, in the present disclosure, it is possible to provide a safe battery module.

In addition, according to an embodiment of the present disclosure, since the present disclosure includes the heat-resistant sheet having the rupture portion with a relatively smaller thickness, it is possible to prevent in advance the case in which, even though gas is discharged from some battery cells, the exposure hole is not opened since the heat-resistant sheet is not ruptured. Accordingly, in the present disclosure, the exposure hole may be reliably opened, thereby preventing that the discharged gas stays inside the cell frame to increase the temperature of other adjacent battery cells and thus propagate thermal runaway. Ultimately, the safety of the battery module may be effectively improved.

<FIG> is a perspective view schematically showing a battery module according to the first embodiment of the present disclosure. <FIG> is a bottom view schematically showing the battery module according to the first embodiment of the present disclosure. <FIG> is an exploded perspective view schematically showing the battery module according to the first embodiment of the present disclosure. Also, <FIG> is a sectional view schematically showing a battery cell of the battery module according to the first embodiment of the present disclosure.

Referring to <FIG>, the battery module <NUM> according to the first embodiment of the present disclosure includes a plurality of battery cells <NUM>, a cell frame <NUM>, a screen member <NUM>, and a protection plate <NUM>.

Here, the battery cell <NUM> may include an electrode assembly <NUM>, a battery can <NUM>, and a cap assembly <NUM>.

The electrode assembly <NUM> may have a structure in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween. Also, a positive electrode tab <NUM> may be attached to the positive electrode plate and connected to the cap assembly <NUM>, and a negative electrode tab <NUM> may be attached to the negative electrode plate and connected to a lower end of the battery can <NUM>.

The battery can <NUM> may have an empty space formed therein to accommodate the electrode assembly <NUM> therein. In particular, the battery can <NUM> may be configured in a cylindrical shape with an open top. Also, the battery can <NUM> may be made of a metal material such as steel or aluminum to secure rigidity. In addition, the negative electrode tab may attached to the lower end of the battery can <NUM> so that not only a lower portion of the battery can <NUM> but also the battery can <NUM> itself may function as the negative electrode terminal <NUM>.

In addition, the battery cell <NUM> may have electrode terminals <NUM> located at one end and the other end thereof, respectively. The plurality of battery cells <NUM> may be electrically connected by a bus bar (not shown) having a metal material. The bus bar may be in the form of a wire or a metal plate. The plurality of battery cells <NUM> may be electrically connected in series, in parallel, or in series and in parallel by the bus bar. For example, although not shown, the bus bar may be accommodated in a recessed groove portion of the cell frame <NUM> so as not to protrude to the outside of the cell frame <NUM>.

The cap assembly <NUM> may be coupled to a top opening of the battery can <NUM> to seal the open end of the battery can <NUM>. The cap assembly <NUM> may have a circular or rectangular shape depending on the shape of the battery can <NUM>, and may include subcomponents such as a top cap C1, a vent unit C2, and a gasket C3.

Here, the top cap C1 may be located at an uppermost portion of the cap assembly <NUM> and configured to protrude upward. In particular, the top cap C1 may function as the positive electrode terminal <NUM> in the battery cell <NUM>. Accordingly, the top cap C1 may be electrically connected to another battery cell <NUM> or a charging device through an external device, for example a bus bar. The top cap C1 may be formed of, for example, a metal material such as stainless steel or aluminum.

In addition, the vent unit C2 may be configured such that the shape of the vent unit C2 is deformed (ruptured) when the internal pressure of the battery cell <NUM>, namely the internal pressure of the battery can <NUM>, increases over a predetermined level, so that the gas inside the battery can <NUM> may be discharged to the outside through an opening D of the top cap C1. Here, the predetermined level of the internal pressure may be <NUM> to <NUM> atmospheres.

Moreover, the gasket C3 may be made of a material having electric insulation so that edge portions of the top cap C1 and the vent unit C2 may be insulated from the battery can <NUM>.

Meanwhile, the cap assembly <NUM> may further include a current interrupt device C4. The current interrupt device C4 is also called CID. When the internal pressure of the battery increases due to gas generation so that the shape of the vent unit C2 is reversed, the contact between the vent unit C2 and the current interrupt device C4 may be cut off or the current interrupt device C4 may be damaged to block the electrical connection between the vent unit C2 and the electrode assembly <NUM>.

The configuration of the battery cell <NUM> is widely known to those skilled in the art at the time of filing of this application and thus will not be described in detail here. In addition, although an example of the battery cell <NUM> is illustrated in <FIG>, the battery module <NUM> according to the present disclosure is not limited to the configuration of the battery cell <NUM> having a specific shape. That is, various types of battery cells <NUM> known at the time of filing of this application may be employed in the battery module <NUM> according to the present disclosure.

In addition, the cell frame <NUM> may have an accommodation space for accommodating the plurality of battery cells <NUM> therein. The cell frame <NUM> may have a plurality of hollows H in a size corresponding to the battery cells <NUM> to accommodate the battery cells <NUM>. For example, as shown in <FIG>, the cell frame <NUM> may include a first frame <NUM> and a second frame <NUM>. The plurality of hollows H may be formed in each of the first frame <NUM> and the second frame <NUM>. The plurality of hollows H may have a shape extending in a vertical direction from the top to the bottom of the cell frame <NUM>. That is, the cell frame <NUM> may have a plurality of exposure holes P1. The exposure hole P1 may be opened so that the gas discharged from the battery cell <NUM> moves to the outside. For example, as shown in <FIG> and <FIG>, the plurality of exposure holes P1 may be formed in each of an upper portion and a lower portion of the cell frame <NUM>. The exposure hole P1 may be formed at a position corresponding to the vent unit C2 of the battery cell <NUM>. For example, in the battery cell <NUM> of <FIG>, since the vent unit C2 is located at the top end of the battery cell <NUM>, the exposure hole P1 may be provided at the top end of the battery cell <NUM>. More specifically, the exposure hole P1 may be provided at a position adjacent to the opening D of the top cap C1 through which the gas discharged from the vent unit C2 is discharged to the outside of the battery can <NUM>.

Preferably, the exposure hole P1 may be formed in a size capable of covering of the opening D of the battery can <NUM> entirely. For example, referring to <FIG> as an example, the top cap C1 of the battery can <NUM> may have a ring-shaped opening D. In this case, the diameter of the exposure hole P1 may be configured to be greater than or equal to the diameter of the ring-shaped opening D.

The screen member <NUM> may be fixed to the cell frame <NUM> to seal the exposure hole P1. In this case, for the fixing, for example, an adhesive may be used so that the screen member <NUM> is attached to the outer surface of the cell frame <NUM>. The screen member <NUM> may be configured such that, when gas is discharged from the vent unit C2 of the battery cell <NUM> to the exposure hole P1, a region thereof corresponding to the exposure hole P1 among the entire region of the screen member <NUM> is ruptured and opened by the gas pressure. In other words, the screen member <NUM> seals the exposure hole P1 at ordinary time, but when a gas explosion occurs in some battery cells <NUM> among the plurality of battery cells <NUM>, the screen member <NUM> may be configured such that a region thereof corresponding to the exposure hole P1 facing the some battery cells <NUM> is converted from a sealed state to an open state by the gas explosion pressure.

In addition, the protection plate <NUM> may be configured to fix the screen member <NUM>. For example, the protection plate <NUM> may be located in close contact with the outer surface of the screen member <NUM> so that the screen member <NUM> is fixed on the cell frame <NUM>. That is, the screen member <NUM> is interposed between the protection plate <NUM> and the cell frame <NUM>. For example, after an adhesive is applied to the outer surface of the screen member <NUM> attached to the outer surface of the cell frame <NUM>, the protection plate <NUM> may be bonded to the outer surface of the screen member <NUM>.

Further, the protection plate <NUM> may have a plate shape extending in a horizontal direction. The protection plate <NUM> may include a plurality of communication holes P2 located corresponding to the exposure holes P1. Therefore, ultimately, the vent unit C2 of the battery cell <NUM>, the opening D of the top cap C1, the exposure hole P1, and the communication hole P2 may all be positioned on the same line. Accordingly, the discharge path of the gas is minimized, and thus the gas may be smoothly discharged to the outside of the battery cell <NUM>. According to this configuration of the present disclosure, since the present disclosure includes the screen member <NUM> configured to seal the exposure hole P1 and ruptured in a region corresponding to the exposure hole P1 by gas pressure and the protection plate <NUM> configured to fix the screen member <NUM>, the gas generated inside the cell frame <NUM> may be discharged to the outside through the open exposure hole P1 and the communication hole P2 communicating with the exposure hole P1. Since the gas discharged to the outside of the cell frame <NUM> is not able to flow into other exposure holes P1 sealed by the screen member <NUM>, it is possible to effectively prevent fire or thermal runaway from propagating to other battery cells <NUM> adjacent to the battery cell <NUM> where the fire or thermal runaway has occurred. Accordingly, in the present disclosure, it is possible to provide a safe battery module <NUM>.

More specifically, the screen member <NUM> may include a heat-resistant sheet <NUM> having a heat-resistant material. For example, the heat-resistant material may be polycarbonate. The heat-resistant sheet <NUM> may be in close contact with the outer surface of the cell frame <NUM> to seal the exposure hole P1. The heat-resistant sheet <NUM> may have a predetermined thickness so that, when the battery cell <NUM> explodes, a portion thereof facing the exposure hole P1 is ruptured by the pressure of the gas discharged during the explosion. For example, the thickness of the heat-resistant sheet <NUM> may be <NUM> to <NUM>. As a portion of the heat-resistant sheet <NUM> is ruptured, gas may be discharged to the outside of the cell frame <NUM> through the exposure hole P1.

In addition, the protection plate <NUM> may have an electric insulating plastic material. For example, the protection plate <NUM> may include polyvinyl chloride. The protection plate <NUM> may be located at an outer side of the heat-resistant sheet <NUM> so that the heat-resistant sheet <NUM> is fixed to the outer surface of the cell frame <NUM>. For example, as shown in <FIG> and <FIG>, the battery module <NUM> of the present disclosure may include the screen member <NUM> and the protection plate <NUM> at the upper portion and the lower portion of the cell frame <NUM>, respectively. At this time, the protection plate <NUM> may be fixed to the outer surface of the heat-resistant sheet <NUM> so that, except for a portion of the heat-resistant sheet <NUM> facing the exposure hole P1, the remaining portion of the heat-resistant sheet <NUM> comes into close contact with the outer surface of the cell frame <NUM>.

Therefore, according to this configuration of the present disclosure, since the present disclosure includes the heat-resistant sheet <NUM> and the protection plate <NUM> for fixing the heat-resistant sheet <NUM>, a region of the heat-resistant sheet <NUM> corresponding to the exposure hole P1 may be opened by the gas discharged from some battery cells <NUM> to effectively discharge the gas to the outside of the cell frame <NUM>, and the battery cells <NUM> are not easily damaged by the flame, thereby safely protecting other battery cells <NUM> where thermal runaway or fire does not occur. That is, in the present disclosure, the sealed state of the exposure holes P1 of the cell frame <NUM> facing the remaining battery cells <NUM> may be continuously maintained, except for the battery cells <NUM> where the explosion has occurred, thereby effectively preventing secondary explosion, fire or thermal runaway from propagating.

<FIG> is a perspective view schematically showing some components of a battery module according to the second embodiment of the present disclosure. Also, <FIG> is a partially sectioned view schematically showing a part of the battery module, taken along the line C-C' of <FIG>.

Referring to <FIG> along with <FIG>, the battery module <NUM> according to the second embodiment of the present disclosure may further include a module case <NUM>. The module case <NUM> may have an inner space configured to accommodate the cell frame <NUM> therein. That is, the module case <NUM> may include an outer wall 150a of a rectangular box shape with an empty interior.

In addition, the module case <NUM> may have a staying space S formed between an outer wall 150a thereof and the cell frame <NUM> spaced apart from each other. The staying space S may communicate with the communication hole P2. The staying space S may be configured to temporarily accommodate the gas discharged from the battery cell <NUM>.

Therefore, according to this configuration of the present disclosure, the present disclosure is configured such that the high-temperature gas discharged by the explosion of the battery cell <NUM> temporarily stays in the staying space S, and it is possible to prevent the gas from flowing again into the cell frame <NUM> through other exposure holes P1 by means of the heat-resistant sheet <NUM> interposed between the cell frame <NUM> and the protection plate <NUM>. Accordingly, the discharged gas is not discharged to the outside of the module case <NUM>, thereby preventing damage to a person or other devices located near the battery module <NUM>.

<FIG> is a partially sectioned view schematically showing a part of a battery module according to the third embodiment of the present disclosure.

Referring to <FIG> along with <FIG>, the battery module according to the third embodiment of the present disclosure is different from the battery module <NUM> according to the first embodiment of <FIG>, in that the protection plate 140A further includes a rib <NUM>. However, other components of the battery module according to the third embodiment of <FIG> are the same as those of the battery module <NUM> of the first embodiment of <FIG> and thus will not be described again.

The protection plate 140A of the battery module <NUM> according to the third embodiment of the present disclosure may include a rib <NUM> protruding from an outer circumference of the communication hole P2 in the outward direction (toward the outer wall 150a of the module case <NUM>). The rib <NUM> may have a tubular shape communicating with the communication hole P2. For example, as shown in <FIG>, the protection plate 140A fixed to the heat-resistant sheet <NUM> may include a rib <NUM> protruding upward from the outer circumference of the communication hole P2.

Therefore, according to this configuration of the present disclosure, since the present disclosure further includes the rib <NUM> on the protection plate 140A, it is possible to prevent the gas discharged from some battery cells <NUM> among the plurality of battery cells <NUM> from directly flowing into the cell frame <NUM> through another communication hole P2 directly adjacent thereto. Accordingly, in the present disclosure, it is possible to safely protect the remaining battery cells <NUM> where thermal runaway or fire does not occur.

<FIG> is a partially sectioned view schematically showing a part of a battery module according to the fourth embodiment of the present disclosure.

Referring to <FIG> along with <FIG>, the battery module according to the fourth embodiment of the present disclosure is different from the battery module <NUM> according to the first embodiment of <FIG>, in that a perforating needle <NUM> is further provided to the protection plate 140B, and other components may be the same.

The perforating needle <NUM> may be provided in the communication hole P2 of the protection plate 140B. The perforating needle <NUM> may include an extending portion 142a extending from an inner surface of the communication hole P2 to a central position of the communication hole P2, and a needle portion 142b provided at an end of the extending portion 142a. When a portion of the heat-resistant sheet <NUM> facing the exposure hole is expands outward (toward the perforating needle) by the gas pressure, the perforating needle <NUM> may be configured to come into contact with a part of the heat-resistant sheet <NUM> to perforate a part of the heat-resistant sheet <NUM>. The needle portion 142b may have a shape sharply protruding toward the heat-resistant sheet <NUM> from the end of the extending portion 142a.

Therefore, according to this configuration of the present disclosure, since the present disclosure includes the perforating needle <NUM> configured to perforate a part of the heat-resistant sheet <NUM>, it is possible to prevent in advance the case in which, even though gas is discharged from some battery cells <NUM>, the exposure hole P1 is not opened since the heat-resistant sheet <NUM> is not ruptured. Accordingly, in the present disclosure, the exposure hole P1 may be reliably opened, thereby preventing that the discharged gas stays inside the cell frame <NUM> to increase the temperature of other adjacent battery cells <NUM> and thus propagate thermal runaway. Ultimately, the safety of the battery module <NUM> may be effectively improved.

<FIG> is a plan view schematically showing a battery module according to the fifth embodiment of the present disclosure.

Referring to <FIG> along with <FIG>, the battery module according to the fifth embodiment of the present disclosure is different from the battery module <NUM> according to the first embodiment, in that the heat-resistant sheet <NUM> of the screen member 130C further includes a rupture portion 131a. Other components are the same as those of the battery module <NUM> according to the first embodiment and thus will not be described again.

The heat-resistant sheet <NUM> of the battery module <NUM> according to the fifth embodiment of the present disclosure may include a rupture portion 131a configured to have a smaller thickness than the remaining portion of the sheet. For example, the rupture portion 131a may have a linear shape. For example, as shown in <FIG>, the rupture portion 131a may have a cross shape in a plan view. The rupture portion 131a may be formed in a portion of the heat-resistant sheet <NUM> facing the exposure hole P1.

Therefore, according to this configuration of the present disclosure, since the present disclosure includes the heat-resistant sheet <NUM> having the rupture portion 131a with a relatively smaller thickness, it is possible to prevent in advance the case in which, even though gas is discharged from some battery cells <NUM>, the exposure hole P1 is not opened since the heat-resistant sheet <NUM> is not ruptured. Accordingly, in the present disclosure, the exposure hole P1 may be reliably opened, thereby preventing that the discharged gas stays inside the cell frame <NUM> to increase the temperature of other adjacent battery cells <NUM> and thus propagate thermal runaway. Ultimately, the safety of the battery module <NUM> may be effectively improved.

<FIG> is a plan view schematically showing a battery module according to the sixth embodiment of the present disclosure.

Referring to <FIG> along with <FIG>, the battery module according to the sixth embodiment of the present disclosure is different from the battery module <NUM> according to the first embodiment, in that the screen member 130D may further include an adhesive sheet <NUM>. The adhesive sheet <NUM> may be provided at an outer side of the heat-resistant sheet <NUM>. That is, the adhesive sheet <NUM> may be located between the heat-resistant sheet <NUM> and the protection plate <NUM> and/or between the heat-resistant sheet <NUM> and the cell frame <NUM>. Other components are the same as those of the battery module <NUM> according to the first embodiment and thus will not be described again.

The adhesive sheet <NUM> may be attached to the protection plate <NUM> to seal the communication hole P2. The adhesive sheet <NUM> may be attached to the outer circumference of the communication hole P2 by the adhesive applied to the adhesive sheet <NUM>. That is, the adhesive sheet <NUM> may be located to cover the communication hole P2.

In addition, the adhesive sheet <NUM> may be configured to be detached from the protection plate <NUM> by explosion pressure when the battery cell <NUM> explodes. That is, the adhesive sheet <NUM> may be pushed out and separated from the protection plate <NUM> by the pressure of the gas introduced into the exposure hole P1.

Therefore, according to this configuration in the present disclosure, since the present disclosure includes the adhesive sheet <NUM>, the adhesive sheet <NUM> may seal the communication hole P2 at ordinary time, and when it is required to discharge gas since some battery cells <NUM> of the plurality of battery cells <NUM> explode, the adhesive sheet <NUM> may open the communication hole P2. Accordingly, in the present disclosure, even if gas explosion occurs in some battery cells <NUM>, the heat-resistant sheet <NUM> for sealing the exposure hole P1 and the adhesive sheet <NUM> for sealing the communication hole P2 perform double sealing, thereby reliably preventing the gas from flowing into other adjacent battery cells <NUM>. Ultimately, the safety of the battery module <NUM> may be improved.

<FIG> is a plan view schematically showing a battery module according to the seventh embodiment of the present disclosure.

Referring to <FIG> along with <FIG>, the battery module according to the seventh embodiment of the present disclosure is different from the battery module <NUM> according to the first embodiment, in that the screen member 130E may have a different configuration. That is, the screen member 130E of the battery module according to the seventh embodiment may include a heat-resistant film <NUM> instead of the heat-resistant sheet <NUM>. However, since other components are the same as those of the battery module <NUM> according to the first embodiment and thus will not be described again.

The heat-resistant film <NUM> may be coated in the exposure hole P1 to seal the exposure hole P1. That is, the heat-resistant film <NUM> may be formed by filling the inside of the exposure hole P1 with a resin having heat resistance and then curing the resin. The heat-resistant film <NUM> may include, for example, polycarbonate. For example, as shown in <FIG>, the heat-resistant film <NUM> may be provided in each of the plurality of exposure holes P1. In some cases, the heat-resistant film <NUM> may be partially interposed and fixed between the outer wall of the cell frame <NUM> and the protection plate <NUM>.

Therefore, according to this configuration of the present disclosure, since the present disclosure includes the heat-resistant film <NUM>, when compared with the heat-resistant sheet <NUM> of the battery module <NUM> of the first embodiment, the amount of the screen member 130E may be minimized, thereby reducing material costs.

Meanwhile, a battery pack according to an embodiment of the present disclosure may include at least one battery module <NUM> and a BMS electrically connected to the battery module <NUM>. The BMS may include various types of circuits or devices to control the charge/discharge of the plurality of battery cells.

Meanwhile, a vehicle (not shown) according to an embodiment of the present disclosure may include at least one battery module <NUM> and a vehicle body having a receiving space in which the battery module <NUM> is received. For example, the vehicle may be an electric vehicle, an electric scooter, an electric wheelchair or an electric bike.

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 module (<NUM>), comprising:
a plurality of battery cells (<NUM>) configured to have electrode terminals (<NUM>) respectively formed at one end and the other end thereof and have a vent unit (C2) that is opened to discharge gas to the outside when an internal pressure increases over a predetermined level;
a cell frame (<NUM>) configured to have an accommodation space for accommodating the plurality of battery cells (<NUM>), the cell frame (<NUM>) having a plurality of exposure holes (P1) opened so that the gas discharged from the battery cell (<NUM>) moves to the outside;
a screen member (<NUM>) fixed to the cell frame (<NUM>) to seal the exposure hole (P1) and configured to open a region thereof corresponding to the exposure hole (P1) by a gas pressure when gas is discharged from the vent unit (C2) of the battery cell (<NUM>); and
a protection plate (<NUM>) located in close contact with the outer surface of the screen member (<NUM>), the protection plate (<NUM>) being configured to fix the screen member (<NUM>) and have a plurality of communication holes (P2) located corresponding to the exposure holes (P1).