Patent Description:
The present disclosure relates to a battery pack, and an electronic device and a vehicle including the battery pack, and more particularly, to a battery pack with improved safety by preventing a secondary explosion or thermal runaway phenomenon.

Recently, as the demand for portable electronic products such as laptops, video cameras and portable telephones is rapidly increasing along with full-scale developments of electric vehicles, energy storage batteries, robots, satellites, and the like, a high-performance secondary battery capable of repetitive charging and discharging is being actively studied.

The lithium secondary battery mainly uses lithium-based oxides and carbonaceous materials as a positive electrode active material and a negative electrode active material, respectively. In addition, the lithium secondary battery includes an electrode assembly in which a positive electrode plate coated with the positive electrode active material and a negative electrode plate coated with the negative electrode active material are disposed with a separator being interposed therebetween, and an exterior, namely a battery case, for hermetically containing the electrode assembly together with an electrolyte.

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

In particular, the demand for large-capacity battery packs applied to electric vehicles is increasing recently. Such a large-capacity battery pack includes a plurality of battery modules. Thus, if a fire or thermal runaway occurs in some of the plurality of battery modules, the fire or thermal runaway propagates to other adjacent battery modules. Accordingly, the safety of the battery pack has become a major problem.

Moreover, the battery pack mounted to a vehicle needs to be prepared for a large impact caused by a vehicle collision. Accordingly, there is a need to solve problems such as damage to internal components in the battery pack caused by an external impact, or a fire or explosion of the secondary batteries. In particular, if a cooling member is damaged, the coolant inside the cooling member leaks out, thereby causing an electrical short between the battery modules.

The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing a battery pack with improved safety by preventing a secondary explosion or thermal runaway phenomenon.

In one aspect of the present disclosure, there is provided a battery pack, comprising: a plurality of battery modules respectively having a discharge port configured to discharge a gas generated therein to the outside; a tray to which the plurality of battery modules are mounted, the tray having a discharge hole for discharging a gas to the outside; and a pair of side covers having body portions elongated in one direction and respectively located at one side and the other side of the tray, a plurality of inlets formed by opening a part thereof and respectively connected to the discharge port, and at least a gas discharge portion configured to transport a gas introduced from the inlet to the discharge hole.

Also, the gas discharge portion may have a sectional area that is gradually increasing as being closer to the discharge hole of the tray.

Moreover, the body portion of the side cover may have an inner space surrounded by an outer wall, and a reinforcing rib extending from an inner surface of one side of the body portion to an inner surface of the other side of the body portion may be provided in the inner space.

In addition, the battery module may include: a plurality of secondary batteries; and a module housing configured to accommodate the plurality of secondary batteries therein, wherein a fixing portion configured to be coupled to the side cover may be provided at at least one of one side and the other side of the module housing.

Also, the plurality of secondary batteries may be configured to discharge a gas in one side direction or in the other side direction when an abnormal behavior occurs.

Moreover, the battery pack may further comprise a cooling pipe configured to allow a coolant to flow therein, wherein the side cover may include a pipe accommodation portion configured to surround at least a part of the cooling pipe so that the cooling pipe is accommodated therein.

In addition, the tray may include a temporary storage portion configured so that when a coolant leaks out from the cooling pipe, the leaked coolant flows into the temporary storage portion.

Also, the side cover may further include a mounting portion having a fastening structure to be coupled to an external device and provided to an outer side of the body portion.

Moreover, the battery module may include a stopper configured to seal the discharge port below a predetermined temperature and to be melt and lost above the predetermined temperature to open the discharge port.

In addition, in another aspect of the present disclosure, there is also provided an electronic device, comprising at least one battery pack.

Also, in another aspect of the present disclosure, there is also provided a vehicle, comprising at least one battery pack.

According to an embodiment of the present disclosure, since the present disclosure includes a pair of side covers having body portions elongated in one direction and respectively located at one side and the other side of the tray, a plurality of inlets formed by opening a part thereof and respectively connected to the discharge port, and a gas discharge portion configured to transport the gas introduced from the inlet to the discharge hole, when a high-temperature gas is generated due to an abnormal behavior such as fire or thermal runaway at any one of the plurality of battery modules, the generated high-temperature gas may be discharged to the outside through the gas discharge portion of the side cover located in an outer direction without raising the temperature of adjacent battery modules, thereby increasing the safety of the battery pack.

Moreover, according to an embodiment of the present disclosure, since the side cover includes a pipe accommodation portion whose outer wall is formed to surround at least a part of the cooling pipe so that the cooling pipe is accommodated therein, the side cover may surround and protect the cooling pipe, thereby preventing the cooling pipe from being damaged due to an external impact.

<FIG> is a perspective view schematically showing a battery pack according to an embodiment of the present disclosure. <FIG> is an exploded perspective view schematically showing components of the battery pack according to an embodiment of the present disclosure. Also, <FIG> is a perspective view schematically showing a plurality of secondary batteries, employed at the battery pack according to an embodiment of the present disclosure.

Referring to <FIG>, a battery pack <NUM> according to an embodiment of the present disclosure includes a plurality of battery modules <NUM>, a tray <NUM>, an upper cover <NUM>, and side covers <NUM> including a pair of side covers 330a, 330b.

Specifically, the battery module <NUM> may include a plurality of secondary batteries100. The secondary battery <NUM> may be a pouch-type secondary battery <NUM> having an electrode assembly (not shown), an electrolyte (not shown) and a pouch <NUM> accommodating them therein. For example, as shown in <FIG>, when viewed directly in the F direction (indicated <FIG>), a plurality of pouch-type secondary batteries, for example, <NUM> pouch-type secondary batteries <NUM> may be stacked side by side in a front and rear direction inside the battery module <NUM>.

Meanwhile, in this specification, unless otherwise specified, the "upper", "lower", "front", "rear", "left" and "right" directions will be based on when viewed in the F direction.

Further, as shown in <FIG>, a positive electrode lead <NUM> and a negative electrode lead <NUM> may be formed at left and right ends opposite to each other with respect to the center of the secondary battery <NUM>. That is, the positive electrode lead <NUM> may be provided at one end (left end) based on the center of the secondary battery <NUM>. In addition, the negative electrode lead <NUM> may be provided at the other end (right end) based on the center of the secondary battery <NUM>.

In addition, the secondary battery <NUM> may have a body provided in the form of standing upright in an upper and lower direction. The body of the secondary battery <NUM> may be elongated in a left and right direction. In addition, the plurality of secondary batteries <NUM> may be configured to discharge a gas in one side direction or the other side direction when an abnormal behavior such as a fire or thermal runaway occurs. For example, if the secondary battery <NUM> is a pouch-type battery, a part B1 of a sealing portion at one side or the other side of the pouch <NUM> may be formed to have a weakened sealing force. Alternatively, a part of the sealing portion at one side or the other side of the pouch may have a narrower sealing area than the other part.

Therefore, according to this configuration of the present disclosure, since the plurality of secondary batteries <NUM> are configured to discharge a gas in one direction or the other direction when an abnormal behavior occurs, it is possible to discharge a gas in an intended direction (towards a discharge port, explained below) from the inside of the battery module <NUM>. Accordingly, it is possible to reduce gas stagnation inside the battery module <NUM>, thereby effectively reducing a secondary explosion or the increase of fire of the secondary battery <NUM> inside the battery module <NUM>.

However, the battery pack <NUM> according to the present disclosure is not limited to the pouch-type secondary battery <NUM> described above, and various types of secondary batteries <NUM> known at the time of filing of this application may be employed.

The battery pack <NUM> may include at least one bus bar (not shown) configured to electrically connect the plurality of secondary batteries <NUM> to each other. Specifically, the bus bar may have a conductive metal, and, for example, may have copper, aluminum, nickel, or the like.

Further, the battery pack <NUM> may include a wire-type bus bar (not shown) for electrically connecting the plurality of battery modules <NUM> to each other.

Meanwhile, each of the plurality of battery modules <NUM> may include a discharge port <NUM>. The discharge port <NUM> may have an opening for discharging the gas generated inside the battery module <NUM> to the outside. The discharge port <NUM> may be formed at one side (for example, in a negative direction of the Y-axis) and/or the other side (for example, in a positive direction of the Y-axis, as shown in <FIG>) of the battery module <NUM>. For example, even if the discharge ports <NUM> are formed at both sides of the battery module <NUM>, any one of the discharge ports <NUM> at one side and the other side may be sealed by blocking the opening.

For example, among six battery modules shown in <FIG>, the battery module <NUM> located at a left side may be sealed by blocking the opening of the discharge port at the other side (right side), and the battery module <NUM> located at a right side may be sealed by blocking the opening of the discharge port at one side (left side).

Further, the discharge port <NUM> may have a tube shape protruding toward the side cover <NUM>. The discharge port <NUM> may be configured to be connected to an inlet E1 of side cover <NUM> so that its end having a tube shape communicates with the inside of the side cover <NUM>.

In addition, the tray <NUM> may be configured so that the plurality of battery modules <NUM> are mounted thereto. The tray <NUM> may include a mount plate <NUM> extending in a horizontal direction (X-axis direction and Y-axis direction). Moreover, the tray <NUM> may have a base plate <NUM> that is coupled to a lower portion of the mount plate <NUM>. The tray <NUM> may include a front frame <NUM> and a rear frame <NUM> having a plate shape standing upright in an upper and lower direction (Z-axis direction). The front frame <NUM> may be coupled to a front end of the mount plate <NUM>. The rear frame <NUM> may be coupled to a rear end of the mount plate <NUM>.

Moreover, the tray <NUM> may have a discharge hole E2 for discharging a gas to the outside. For example, as shown in <FIG>, the discharge hole E2 may be formed at each of a left side and a right side of the front frame <NUM>. The discharge hole E2 may have an open shape so that the inside and the outside of the battery pack <NUM> communicate with each other.

In addition, the upper cover <NUM> may be coupled to an upper portion of the tray <NUM>. The upper cover <NUM> may have a size capable of covering the plurality of battery modules <NUM> mounted to the tray <NUM>.

<FIG> is a partial sectional view schematically showing the battery pack of <FIG>, taken along the line C-C'.

Referring to <FIG> along with <FIG>, the side cover <NUM> may have a shape elongated in one direction (X-axis direction). The side cover <NUM> may be shaped by extrusion molding. The front end of the side cover <NUM> may be coupled to the front frame <NUM>. The rear end of the side cover <NUM> may be coupled to the rear frame <NUM>.

Further, the side cover <NUM> may be positioned at each of one side and the other side of the mount plate <NUM> of the tray <NUM>. For example, as shown in <FIG> and <FIG>, two side covers <NUM> may have body portions <NUM> located at left and right ends of the mount plate <NUM>, respectively. Accordingly, the body portions <NUM> may serve as a left wall and a right wall of the battery pack <NUM>. The body portions <NUM> may have a shape extending in a front and rear direction (X-axis direction). For example, the body portion <NUM> may be formed in a plate shape by extrusion molding in a front and rear direction. The body portions <NUM> may have a shape standing upright in an upper and lower direction. The body portions <NUM> may have a plate shape with an empty inside.

In addition, the side cover <NUM> may include an inlet E1 formed by opening a part thereof. For example, the inlet E1 may be formed by opening a part of a gas discharge portion <NUM> of side cover <NUM>, explained later. The inlet E1 may be configured so that the outside and the inside of the side cover <NUM> may communicate with each other. Each of the plurality of inlets E1 may be connected to the discharge port <NUM>. That is, the inlet E1 may be configured to face the opening of the discharge port <NUM> so that the gas discharge portion <NUM> and the discharge port <NUM> communicate with each other.

Moreover, the gas discharge portion <NUM> may have a shape extending in one direction to transport the gas introduced from the inlet E1 to the discharge hole E2. The gas discharge portion <NUM> may be formed at an inner side of the body portion <NUM>. The gas discharge portion <NUM> may have a tube shape that extends in a front and rear direction and has an empty inside by means of extrusion molding. For example, as shown in <FIG>, each of the two side covers <NUM> may have a gas discharge portion <NUM>, and the gas discharge portion <NUM> may have a shape extending in a front and rear direction. A front end of the gas discharge portion <NUM> may be configured to be connected to the discharge hole E2 provided in the front frame <NUM>.

In addition, the gas discharge portion <NUM> may be located above a pipe accommodation portion <NUM>, explained later. Accordingly, the gas discharge portion <NUM> may utilize the empty space of the battery pack <NUM> formed in an upper and lower direction (Z-axis direction), so that the battery module <NUM> having a higher capacity may be mounted to the tray <NUM>. That is, it is possible to increase the energy density of the battery pack <NUM>.

Therefore, according to this configuration of the present disclosure, since the present disclosure includes a pair of side covers 330a, 330b having body portions <NUM> elongated in one direction and respectively located at one side and the other side of the tray <NUM>, a plurality of inlets E1 formed by opening a part thereof and respectively connected to the discharge port <NUM>, and a gas discharge portion <NUM> configured to transport the gas introduced from the inlet E1 to the discharge hole E2, when a high-temperature gas is generated due to an abnormal behavior such as fire or thermal runaway at any one of the plurality of battery modules <NUM>, the generated high-temperature gas may be discharged to the outside through the gas discharge portion <NUM> of the side cover <NUM> located in an outer direction (Y-axis direction) without raising the temperature of adjacent battery modules <NUM>, thereby increasing the safety of the battery pack <NUM>.

That is, in the present disclosure, the high-temperature gas generated from the battery module <NUM> may be transported to the side cover <NUM>, thereby minimizing the effect of the high-temperature gas. Accordingly, when a fire or thermal runaway occurs at one battery module <NUM>, it is possible to effectively prevent the thermal runaway or fire from spreading successively to other adjacent battery modules <NUM>.

Moreover, since the side cover <NUM> is positioned at one side or the other side of the tray <NUM>, it is possible to protect the plurality of battery modules <NUM> from impacts in a front and rear direction and a left and right direction. Accordingly, it is possible to increase the safety of the battery pack <NUM>.

<FIG> is a partial sectional view schematically showing a gas discharge portion, employed at the battery pack according to an embodiment of the present disclosure.

Referring to <FIG> along with <FIG> and <FIG>, the side cover <NUM> of <FIG> may is different from the side cover <NUM> of <FIG> in view of the shape of the gas discharge portion 335A. For example, the gas discharge portion 335A of the side cover <NUM> may be configured such that the sectional area of its inner tube is gradually increasing as being closer to the discharge hole E2 of the tray <NUM>. That is, in the gas discharge portion 335A, the inner diameter D1 of the inner tube located far from the discharge hole E2 of the tray <NUM> may be smaller than the inner diameter D2 of the inner tube located close to the discharge hole E2.

Accordingly, in the present disclosure, since the gas discharge portion 335A is configured to have an increasing sectional area in a direction G toward the discharge hole E2, among the entire region of the gas discharge portion 335A, a region close to the discharge hole E2 has a largest sectional area, so the region close to the discharge hole E2 may have a small internal pressure compared to the region located far from the discharge hole E2. Accordingly, it is possible to guide the gas introduced into the gas discharge portion 335A to move toward the discharge hole E2 of the gas discharge portion 335A where a relatively low pressure is formed.

Therefore, according to this configuration of the present disclosure, since the gas discharge portion 335A is configured so that its sectional area is gradually increasing as being closer to the discharge hole E2 of the tray <NUM>, the gas may be guided to move to the discharge hole E2 so that the gas may be discharged quickly, thereby improving the safety of the battery pack <NUM>.

Meanwhile, referring to <FIG> again along with <FIG>, the body portion <NUM> of the side cover <NUM> may have an inner space surrounded by an outer wall. A reinforcing rib R1 may be provided in the inner space to extend from an inner surface of one side thereof to an inner surface of the other side thereof. For example, as shown in <FIG>, the inner space surrounded by an outer wall may be formed inside the body portion <NUM> of the side cover <NUM>. In the inner space, a plurality of reinforcing ribs R1 may be shaped to extend from an inner surface of one side thereof to an inner surface of the other side thereof.

In addition, the reinforcing rib R1 has a linear sectional area. The reinforcing rib R1 may have a shape elongated in a portion of the body portion <NUM>, but it is also possible that the reinforcing rib R1 has a shape elongated from a front end to a rear end of the body portion <NUM>. However, the reinforcing rib R1 is not necessarily provided only to the body portion <NUM> of the side cover <NUM>, and the reinforcing rib R1 may also be provided to the gas discharge portion <NUM>, a mounting portion <NUM>, explained later, and the pipe accommodation portion <NUM>. That is, the gas discharge portion <NUM>, the mounting portion <NUM> and the pipe accommodation portion <NUM> are components of the side cover <NUM>, and when an external impact is applied to the battery pack <NUM>, the reinforcing rib R1 may protect the internal components by means of its characteristic mechanical rigidity.

Therefore, according to this configuration of the present disclosure, since the reinforcing rib R1 is formed in the inner space of the side cover <NUM>, it is possible to effectively increase the mechanical rigidity of the side cover <NUM>. Accordingly, the battery pack <NUM> may safely protect the plurality of battery modules <NUM> from external impacts in a left and right direction and a front and rear direction.

<FIG> is a bottom view schematically showing a battery module, employed at the battery pack according to an embodiment of the present disclosure.

Meanwhile, referring to <FIG> and <FIG>, the battery module <NUM> of the battery pack of the present disclosure may include a module housing <NUM>. The module housing <NUM> may have an inner space for accommodating the plurality of secondary batteries <NUM> therein. The module housing <NUM> may include a fixing portion <NUM> configured to be coupled to the side cover <NUM>. The fixing portion <NUM> may be formed at one side and/or the other side of the module housing <NUM>.

For example, as shown in <FIG>, among the plurality of battery modules <NUM>, a battery module <NUM> disposed at a right side may have a fixing portion <NUM> formed at a right side thereof. Conversely, a battery module <NUM> disposed a left side may have a fixing portion <NUM> formed at a left side thereof. Alternatively, fixing portions <NUM> may be provided at both sides of the battery module <NUM>. The battery module <NUM> may have two fixing portions <NUM> at one side or the other side thereof. For example, the two fixing portions <NUM> may have a coupling hole H3 formed at a position corresponding to a fastening hole H1 formed in the side cover <NUM>. The fixing portion <NUM> may be coupled to the side cover <NUM> using a fastening bolt (not shown) and a nut (not shown) respectively inserted into the fastening hole H1 and the coupling hole H3.

Therefore, according to this configuration of the present disclosure, since the fixing portion <NUM> configured to be coupled to the side cover <NUM> is provided to at least one of one side and the other side of the module housing <NUM>, the plurality of battery modules <NUM> may be fixed to the side cover <NUM>. Accordingly, when the battery pack <NUM> is mounted to a vehicle exposed to a frequent vibration environment, damage to the battery module <NUM> caused by frequent vibration may be effectively reduced.

Meanwhile, referring to <FIG>, <FIG> and <FIG> again, the battery pack <NUM> may further include a cooling pipe <NUM> configured to allow a coolant (not shown) to flow therein. The cooling pipe <NUM> may have a pipe shape. The coolant may be water.

In addition, the side cover <NUM> may include a pipe accommodation portion <NUM> configured to accommodate the cooling pipe <NUM> therein. The pipe accommodation portion <NUM> may be a space whose outer wall is formed to surround at least a part of the cooling pipe <NUM>. For example, as shown in <FIG>, the pipe accommodation portion <NUM> includes a part 339a extending in an inner direction (left direction) from the inner surface of the body portion <NUM>, and a remaining part 339b extending from an end of the extended part 339a in a lower direction.

Therefore, according to this configuration of the present disclosure, since the side cover <NUM> includes a pipe accommodation portion <NUM> whose outer wall is formed to surround at least a part of the cooling pipe <NUM> so that the cooling pipe <NUM> is accommodated therein, the side cover <NUM> may surround and protect the cooling pipe <NUM>, thereby preventing the cooling pipe <NUM> from being damaged due to an external impact.

Meanwhile, referring to <FIG> again, the tray <NUM> may include a temporary storage portion <NUM>. Specifically, the temporary storage portion <NUM> may be configured such that when a coolant leaks out from the cooling pipe <NUM>, the leaked coolant flows therein. For example, as shown in <FIG>, the temporary storage portion <NUM> may be formed in a space between the mount plate <NUM> and the base plate <NUM>.

In addition, an end 323a of the mount plate <NUM> may be configured to be spaced apart from the body portion <NUM> of the side cover <NUM>. If a coolant leaks out from the cooling pipe <NUM>, the leaked coolant may flow into the temporary storage portion <NUM> through a spaced gap between the end 323a of the mount plate <NUM> and the side cover <NUM>.

Therefore, according to this configuration of the present disclosure, since the tray <NUM> includes a temporary storage portion <NUM> configured such that when a coolant leaks out from the cooling pipe <NUM>, the leaked coolant flows therein, it is possible to prevent the leaked coolant from flowing into the battery module <NUM>, thereby preventing the occurrence of an electric leakage, a circuit interruption, a short circuit, or the like of the battery module <NUM> by the coolant.

Meanwhile, referring to <FIG> again, the side cover <NUM> may further include a mounting portion <NUM>. The mounting portion <NUM> may be provided to an outer side of the body portion <NUM> to be coupled to an external device. The mounting portion <NUM> may have a fastening structure to be coupled to an external device. For example, the mounting portion <NUM> may be bolted to a component in a vehicle body. For the bolting connection, the mounting portion <NUM> may have a bolting hole H2 into which a bolt is inserted.

Therefore, according to this configuration of the present disclosure, since the side cover <NUM> further includes a mounting portion <NUM> having a fastening structure to be coupled to an external device and provided at an outer side of the body portion <NUM>, the battery pack <NUM> may be stably fixed to an external device.

Moreover, the mounting portion <NUM> may be configured to protect the plurality of battery modules <NUM> located therein from an external impact. To this end, the mounting portion <NUM> may have a shape protruding outward from the body portion <NUM>. The mounting portion <NUM> may be formed to have a hollow therein. That is, the mounting portion <NUM> may have a shape protruding outward to absorb or prevent an impact applied to the left and right sides of the battery pack <NUM>.

<FIG> is a partial bottom view schematically showing a battery module, employed at a battery pack according to another embodiment of the present disclosure.

Referring to <FIG> along with <FIG> and <FIG>, a battery module 200B of the battery pack according to another embodiment of the present disclosure may include a stopper <NUM> in the discharge port <NUM>. The stopper <NUM> may seal an outlet of the discharge port <NUM> below a predetermined temperature. The stopper <NUM> may be configured to be melt and lost above the predetermined temperature. For example, the stopper <NUM> may have a material with a melting point of <NUM> or higher. For example, the stopper <NUM> may be made of a paraffin material. The stopper <NUM> may be configured to open the discharge port <NUM>, for example, at <NUM> by being melted and lost.

Therefore, according to this configuration of the present disclosure, since the battery module 200B of the present disclosure includes a stopper <NUM> configured to seal the discharge port <NUM> below a predetermined temperature and to be melt and lost above the predetermined temperature to open the discharge port <NUM>, the stopper <NUM> is melt and lost due to a high-temperature gas of the battery module 200B where a fire or thermal runaway occurs, thereby opening the discharge port <NUM> to discharge the high-temperature gas to the outside. The discharge port <NUM> is sealed during ordinary times when the internal temperature is maintained below the predetermined temperature, thereby preventing foreign substances (conductive substances) from flowing into the battery module 200B.

Moreover, by applying the stopper <NUM>, when high-temperature gas is discharged from the battery module 200B where a fire or thermal runaway occurs, the battery module 200B of the present disclosure may prevent the gas moving to the gas discharge portion <NUM> from flowing into other adjacent battery modules 200B through the discharge port <NUM> of the adjacent battery modules 200B.

Meanwhile, the battery pack <NUM> according to an embodiment of the present disclosure may further include various devices (not shown) for controlling the charging and discharging of the battery module <NUM>, for example, a BMS (Battery Management System), a current sensor, a fuse, and the like.

Meanwhile, an electronic device (not shown) according to an embodiment of the present disclosure includes at least one battery pack <NUM> described above. The electronic device may further include a device housing (not shown) having an accommodation space for accommodating the battery pack <NUM>, and a display unit through which the user may check the state of charge of the battery pack <NUM>.

In addition, the battery pack <NUM> according to an embodiment of the present disclosure may be included in a vehicle such as an electric vehicle or a hybrid electric vehicle. That is, the battery pack <NUM> according to an embodiment of the present disclosure as described above may be mounted in a vehicle body of the vehicle according to an embodiment of the present disclosure. At this time, the side cover <NUM> may be coupled to a vehicle body of the vehicle.

Meanwhile, even though the terms indicating directions such as upper, lower, left, right, front and rear directions are used in the specification, it is obvious to those skilled in the art that these merely represent relative positions for convenience in explanation and may vary based on a position of an observer or an object.

Claim 1:
A battery pack (<NUM>), comprising:
a plurality of battery modules (<NUM>) respectively having a discharge port (<NUM>) configured to discharge a gas generated therein to the outside;
a tray (<NUM>) to which the plurality of battery modules (<NUM>) are mounted, the tray (<NUM>) having a discharge hole (E2) for discharging a gas to the outside; and
a pair of side covers (<NUM>, 330a, 330b) having body portions (<NUM>) elongated in one direction and respectively located at one side and the other side of the tray (<NUM>), a plurality of inlets (E1) formed by opening a part thereof and respectively connected to the discharge port (<NUM>), and at least a gas discharge portion (<NUM>) configured to transport a gas introduced from the inlet (E1) to the discharge hole (E2).