Battery pack

Abstract

A battery pack according to one embodiment of the present invention may include a case providing an internal space and having a pack cover; a battery cell located inside the case; a partition wall dividing the internal space of the case; and a melting bolt connecting the pack cover and the partition wall, wherein the melting bolt is configured to melt at a specific temperature.

Description

Technology Field

[0001] The present invention relates to a battery pack.

[0002] This application is a priority claim application for Korean Patent Application No. 10-2024-0050779 filed on April 16, 2024, and all contents disclosed in the specification and drawings of said application are incorporated into this application by reference. Background Technology

[0003] Recently, rechargeable batteries capable of repeated charging and discharging are being widely used for driving or energy storage not only in small portable electronic devices such as smartphones, tablet PCs, and smartwatches, but also in medium and large-sized devices such as electric vehicles (EVs) and energy storage systems (ESS), and research on this is actively underway.

[0004] Currently commercialized rechargeable batteries include nickel-cadmium, nickel-hydrogen, nickel-zinc, and lithium-ion batteries. Among these, lithium-ion batteries are gaining attention for their advantages, such as the ability to charge and discharge freely with almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density.

[0005] These lithium secondary batteries primarily use lithium-based oxides and carbon materials as the positive and negative active materials, respectively. The lithium secondary battery comprises an electrode assembly in which a positive plate and a negative plate, each coated with the positive and negative active materials, are arranged with a separator in between, and an outer casing, namely a battery case, that seals and houses the electrode assembly together with an electrolyte.

[0006] Generally, lithium secondary batteries can be classified according to the shape of the casing into can-type secondary batteries, in which the electrode assembly is embedded in a metal can, and pouch-type secondary batteries, in which the electrode assembly is embedded in a pouch of aluminum laminate sheet.

[0007] Recently, secondary batteries are widely used for driving or energy storage not only in small devices such as portable electronic devices but also in medium-to-large devices such as electric vehicles and Energy Storage Systems (ESS). A single battery module can be formed by housing multiple such secondary batteries together inside a module case while electrically connected. In this case, each secondary battery included in a single battery module can be referred to as a battery cell. Furthermore, multiple such battery modules can be connected to form a single battery pack.

[0008] As secondary batteries in the form of battery modules and battery packs, consisting of multiple connected battery cells, have begun to be widely used, ignition and explosion accidents are occurring, and battery safety issues are emerging as an increasingly important concern.

[0009] However, when a battery pack contains multiple battery modules, and each module contains multiple battery cells, it may be vulnerable to thermal chain reactions between modules or cells. For example, if an event such as thermal runaway occurs within a single battery module, it is necessary to suppress the propagation of this runaway to other battery modules or cells. If the propagation of thermal runaway between modules or cells is not properly suppressed, an event originating in a specific module or cell may trigger a chain reaction of thermal reactions in other modules or cells, potentially causing explosions or fires, or significantly amplifying their scale.

[0010] For example, if an event such as thermal runaway occurs in a single battery module, gases or flames may be randomly released to the outside. If the release of such gases or flames is not properly controlled, they may be released toward other battery modules, potentially causing a thermal chain reaction in those modules. In particular, module terminals may be located on the front side of the battery module to provide electrical connections to other battery modules or battery packs, such as module busbars. Therefore, if flames are released toward the front of such a battery module, they can damage the module terminals within the battery pack and cause an electrical short circuit. Furthermore, since other battery modules may be located in front of the battery module, if flames are released toward the front of a specific battery module, the released flames may spread toward other modules, making it easy for fire to spread between battery modules.

[0011] If thermal propagation between battery modules or between battery cells is not properly controlled, a rapid voltage drop in the battery module or battery pack may occur. This can lead to a sudden shutdown of the device equipped with the battery module or battery pack, causing unexpected damage. For example, if a sudden voltage drop in the battery pack occurs while an electric vehicle is in operation, there may not be enough time to move the electric vehicle to a safe location.

[0012] Furthermore, if thermal propagation between battery modules or battery cells is not properly controlled and a fire or explosion occurs suddenly, there is a high possibility of causing casualties to users. For example, if thermal runaway occurs in an electric vehicle and a certain amount of time is not secured before it progresses into a full-scale fire, the occupants may not be able to escape safely. The problem to be solved

[0013] The present invention provides a battery pack with an improved structure capable of appropriately controlling the emission of flames, etc., generated inside a battery module, and an automobile including the same.

[0014] In addition, the present invention provides a structure that facilitates the expansion of the internal space of a battery pack when a thermal event occurs inside a battery module.

[0015] In addition, the present invention may provide a structure in which the pack cover can easily swell when a thermal event occurs inside the battery module.

[0016] In addition, the present invention provides a structure in which the sealing of a battery pack is maintained when a thermal event occurs inside a battery module.

[0017] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by those skilled in the art from the description of the invention below. means of solving the problem

[0018] A battery pack according to one embodiment of the present invention comprises: a case providing an internal space and having a pack cover; a battery cell located inside the case; a partition wall dividing the internal space of the case; and a melting bolt connecting the pack cover and the partition wall, wherein the melting bolt is configured to melt at a specific temperature.

[0019] The above melting bolt may be configured to melt when a thermal event occurs in the battery cell.

[0020] The above melting bolt may include plastic material.

[0021] The battery pack further includes a nut located between the pack cover and the partition wall, and the melting bolt passes through the pack cover and the nut and at least a portion can be inserted into the partition wall.

[0022] The above nut can be coupled to the inner surface of the pack cover.

[0023] The melting bolt comprises: a first part passing through the pack cover and the nut; and a second part extending from the first part and inserted into the partition wall, wherein the first part may be formed to be longer than the second part.

[0024] The melting bolt above may be configured so that the first part and the second part are separated when a thermal event occurs.

[0025] The above partition wall has an insertion hole into which the melting bolt is inserted, and the sum of the thickness of the pack cover and the thickness of the nut can be formed to be longer than the depth of the insertion hole.

[0026] The above melting bolts are provided in multiple numbers, and the multiple melting bolts can be arranged along the length direction of the partition wall.

[0027] The battery pack is installed inside the case and further includes a module case that accommodates the battery cell, and the module case may have a venting hole facing the pack cover.

[0028] An automobile according to one aspect of the present invention includes a battery pack of the present invention.

[0029] A battery pack case according to one embodiment of the present invention comprises: a flat base plate; a side wall installed along the perimeter of the base plate on the upper surface of the base plate; a flat pack cover coupled to the upper surface of the side wall to form an internal space together with the base plate; a partition wall installed on the upper surface of the base plate to partition the internal space; and a melting bolt for fastening the pack cover and the partition wall, wherein the melting bolt is configured to melt at a specific temperature.

[0030] The melting bolt is configured to melt when a thermal event occurs in the battery cell.

[0031] The above melting bolt includes plastic material.

[0032] The battery pack case further includes a nut located between the pack cover and the partition wall, and the melting bolt passes through the pack cover and the nut and at least a portion is inserted into the partition wall.

[0033] The melting bolt comprises a first part passing through the pack cover and the nut; and a second part extending from the first part and inserted into the partition wall, wherein the first part is formed to be longer than the second part.

[0034] The melting bolt is configured such that the first part and the second part separate when a thermal event occurs in the battery cell.

[0035] A battery pack according to one aspect of the present invention includes the pack case. Effects of the invention

[0036] According to at least one of the embodiments of the present invention, when gas or flame is generated inside a battery module, the discharge of such gas or flame can be appropriately controlled.

[0037] According to at least one of the embodiments of the present invention, the electrical safety of the battery pack can be improved.

[0038] According to at least one of the embodiments of the present invention, the sealing of the battery pack can be maintained even if a thermal event occurs inside the battery module.

[0039] According to at least one of the embodiments of the present invention, when a thermal event occurs inside a battery module, the internal space of the battery pack expands, thereby preventing or suppressing the explosion of the battery pack. Brief explanation of the drawing

[0040] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a drawing showing a battery pack according to one embodiment of the present invention. Figure 2 is a diagram showing a partial configuration of the battery pack of Figure 1 separated. Figure 3 is a diagram showing a partial configuration of the battery pack of Figure 2 separated. Figure 4 is a drawing showing the battery module of Figure 3. Figure 5 is a diagram showing a partial configuration of the battery module of Figure 4 separated. Figure 6 is a drawing showing the cross-sectional configuration along the cutting line C-C' of Figure 2. Figure 7 is a drawing showing the cross-sectional configuration along the cutting line A-A' of Figure 1. Figure 8 is a diagram showing the cross-sectional configuration along the cutting line A-A' of Figure 1 when a thermal event occurs. Figure 9 is a diagram showing the cross-sectional configuration along the cutting line A-A' of Figure 1 when a thermal event occurs. Figure 10 is a diagram showing the cross-sectional configuration along the cutting line B-B' of Figure 1 when a thermal event occurs. FIG. 11 is a perspective view illustrating an electric vehicle including a battery pack according to one embodiment of the present invention. In parts of the attached drawings, corresponding components are given the same reference numerals. Those skilled in the art understand that the drawings are intended to illustrate elements simply and clearly and are not necessarily drawn to scale. For example, to aid in understanding various embodiments, the dimensions of some elements depicted in the drawings may be exaggerated compared to others. Additionally, elements of known technology that are useful or essential in commercially viable embodiments may often be omitted so as not to hinder the spirit of the various embodiments of the present invention. Specific details for implementing the invention

[0041] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, and should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0042] Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and that there may be various equivalents and modifications that can replace them.

[0043] FIG. 1 is a drawing showing a battery pack (10) according to an embodiment of the present invention. FIG. 2 is a drawing showing a partial configuration of the battery pack (10) of FIG. 1 separated. FIG. 3 is a drawing showing a partial configuration of the battery pack (10) of FIG. 2 separated.

[0044] Referring to FIGS. 1 to 3, a battery pack (10) according to one embodiment of the present invention may include a pack case (100), a battery module (200), a partition wall (300), and a melting bolt (400).

[0045] The pack case (100) of the battery pack (10) may include a base plate (110), a side wall (120), and a pack cover (150). The base plate (110) may have a square shape. The base plate (110) may have a flat shape. The base plate (110) may form the exterior of the battery pack (10). The base plate (110) may provide an internal space for the battery pack (10).

[0046] The side wall (120) may be installed, fastened, joined, fixed, or attached to the upper surface of the base plate (110). According to one embodiment, the side wall (120) may be composed of four. The side wall (120) may be arranged along the perimeter of the base plate (110). The side wall (120) may form the exterior of the battery pack (10). The side wall (120) may provide an internal space.

[0047] The pack cover (150) may have a square plate shape. According to one embodiment, the pack cover (150) may have a flat plate shape. The pack cover (150) may form the exterior of the battery pack (10). The pack cover (150) may cover the internal space of the battery pack (10).

[0048] The battery module (200) may refer to a secondary battery module. For example, the battery module (200) may be a pouch-type secondary battery. However, the shape of the battery module (200) is not limited to a pouch shape and may have various shapes such as a cylindrical shape or a rectangular parallelepiped shape. The battery module (200) may be provided in multiple numbers.

[0049] The partition wall (300) may include a first partition wall (310) and a second partition wall (320). The partition wall (300) may be provided in multiple numbers. The partition wall (300) may be installed, fastened, fixed, coupled, or attached to the upper surface of the base plate (110) of the pack case (100). The partition wall (300) may partition the internal space of the battery pack (10). A battery module (200) may be located in the space partitioned by the partition wall (300). The partition wall (300) may be configured as a separate structure, or, for example, may be configured integrally with a part of the pack case (100). According to one embodiment, the partition wall (300) may be configured integrally with the base plate (110) of the pack case (100).

[0050] The melting bolt (400) can fasten, combine, install, or secure the pack cover (150) of the pack case (100) and the partition wall (300). According to one embodiment, the melting bolt (400) may include a material that melts at low temperatures.

[0051] According to this configuration of the present invention, the thermal safety of the battery pack (10) can be improved. When a thermal event occurs from the battery module (200), venting gas can be discharged. As a result, the pressure inside the battery pack (10) can increase rapidly. At this time, the melting bolt (400) can melt due to the temperature of the venting gas. As a result, the pack cover (150) and the partition wall (300) can be separated. And as the pack cover (150) bulges outward, the space inside the battery pack (10) can be expanded. As a result, the explosion of the battery pack (10) can be prevented.

[0052] Referring to FIGS. 1 to 3, the melting bolts (400) of the battery pack (10) according to one embodiment of the present invention may be provided in plurality. The plurality of melting bolts (400) may be arranged along the longitudinal direction of the partition wall (300). The first partition wall (310) of the partition wall (300) may be extended along the left-right direction or the Y-axis direction. The second partition wall (320) of the partition wall (300) may be extended along the front-back direction or the X-axis direction. The plurality of melting bolts (400) may be arranged along the longitudinal direction of the first partition wall (310) of the partition wall (300) or along the longitudinal direction of the second partition wall (320) of the partition wall (300).

[0053] According to this configuration of the present invention, the thermal safety of the battery pack (10) can be improved. By joining a plurality of melting bolts (400) along the partition wall (300), the pack cover (150) can be stably joined. In addition, when a thermal event occurs in the battery module (200), the pack cover (150) can swell up completely.

[0054] Referring to FIGS. 1 to 3, a battery pack (10) according to one embodiment of the present invention may include a venting device (500). According to one embodiment, the venting device (500) may be installed on a side wall (120) of a pack case (100). For example, the venting device (500) may be installed on a front side wall (120) of the pack case (100). For example, the venting device (500) may be a gas valve and may optionally switch between an open state and a closed state. The venting device (500) may switch to an open state to discharge gas when the pressure inside the pack case (100) increases. Additionally, the venting device (500) may switch to a closed state to block external air from entering the pack case (100). A plurality of venting devices (500) may be provided.

[0055] According to this configuration of the present invention, the thermal safety of the battery pack (10) can be improved. When a thermal event occurs from the battery module (200), the pressure inside the battery pack (10) may increase rapidly. At this time, the venting device (500) vents the venting gas to the outside, and the pack cover (150) swells outward, thereby preventing or suppressing the explosion of the battery pack (10).

[0056] FIG. 4 is a drawing showing the battery module (200) of FIG. 3. FIG. 5 is a drawing showing a partial configuration of the battery module (200) of FIG. 4 separated.

[0057] Referring to FIGS. 1 to 5, a battery pack (10) according to one embodiment of the present invention may include a plurality of battery modules (200). A battery module (200) may include a module case (210), a plurality of battery cells (220), a module pad (250), a busbar frame assembly (230), and an end cover (240).

[0058] The module case (210) may have a rectangular shape. The module case (210) may also be referred to as a frame (210). The module case (210) may provide space inside. The module case (210) may be equipped with a top plate, a bottom plate, and a pair of side plates. Additionally, the module case (210) may have a shape with an open front and rear. The module case (210) may be equipped with a venting hole (211) in the top plate. The venting hole (211) may connect the inside and outside of the module case (210).

[0059] A battery cell (220) can be accommodated inside a module case (210). A plurality of battery cells (220) can be stacked in the left-right direction or the Y-axis direction. A battery cell (220) may include a storage portion (221) having an electrode assembly, a first sealing portion (222) protruding to the front and rear sides of the storage portion (221), and a second sealing portion (223) protruding to the upper side of the storage portion (221). Additionally, a battery cell (220) may include electrode leads (224) protruding to the front and rear sides of the first sealing portion (222), respectively. Each battery cell (220) may be extended along the front-rear direction or the X-axis direction. The electrode leads (121) may protrude to the front and rear of each battery cell (220).

[0060] A module pad (250) may be placed between a plurality of battery cells (220). The module pad (250) may be placed between at least some of the battery cells (220) and / or outside the stack. For example, the module pad (250) may be configured to be placed between adjacent battery cells (220) in four battery cells (220) stacked in the left-right direction.

[0061] These module pads (250) may be provided with an elastic material to absorb swelling of the battery cell (220). For example, the module pads (250) may be composed of a foam material such as polyurethane. Alternatively, the module pads (250) may be provided with a material capable of blocking heat or flames. For example, the module pads (250) may be provided with an insulating or fireproof material such as silicone or mica.

[0062] A busbar frame assembly (230) may be provided at the front and rear of each of the plurality of battery cells (220). The busbar frame assembly (230) may be electrically connected to the electrode leads (121) of the plurality of battery cells (220).

[0063] A pair of end covers (240) can be attached to the front and rear of the module case (210), respectively. A pair of end covers (240) can cover the front and rear of the module case (210). The end covers (240) can have a rectangular shape.

[0064] The battery module (200) may be installed, fastened, coupled, fixed, or attached to the upper surface of the base plate (110) of the pack case (100). When a thermal event occurs from the battery module (200), the venting gas (g) may be discharged through the venting hole (211) formed in the top plate of the module case (210). The venting hole (211) may face the inner surface of the pack cover (150) of the pack case (100). The venting gas (g) discharged through the venting hole (211) of the module case (210) may push the pack cover (150) of the pack case (100) outward, upward, or in the Z-axis direction.

[0065] The battery module (200) may be located in a space partitioned by a partition wall (300) installed inside the pack case (100). Additionally, the partition wall (300) may face at least one side of the battery module (200).

[0066] FIG. 6 is a drawing showing a cross-sectional configuration along the cutting line C-C' of FIG. 2. FIG. 7 is a drawing showing a cross-sectional configuration along the cutting line A-A' of FIG. 1.

[0067] Referring to FIGS. 6 and 7, a battery pack (10) according to one embodiment of the present invention may include a nut (152). The nut (152) may be located between a pack cover (150) and a partition wall (300). A melting bolt (400) may pass through the nut (152). Additionally, the melting bolt (400) may pass through the pack cover (150). At least a portion of the melting bolt (400) may be inserted, fastened, joined, or fixed to the partition wall (300).

[0068] The pack cover (150) may include a fastening hole (151). The partition wall (300) may include an insertion hole (301). The fastening hole (151) formed in the pack cover (150) and the insertion hole (301) formed in the partition wall (300) may each have screw threads. A melting bolt (400) may be coupled to the screw threads of the fastening hole (151) and nut (152) formed in the pack cover (150) and the insertion hole (301) formed in the partition wall (300).

[0069] According to this configuration of the present invention, the pack cover (150) and the partition wall (300) can be stably combined, fastened, or fixed. The nut (152) can increase the bonding strength between the pack cover (150) and the partition wall (300).

[0070] Referring to FIGS. 6 and 7, a nut (152) of a battery pack (10) according to one embodiment of the present invention may be coupled to an inner surface of a pack cover (150). For example, the nut (152) may be welded to an inner surface of the pack cover (150). Additionally, the nut (152) and the pack cover (150) may be formed integrally. The nut (152) may be positioned to face a fastening hole (151) formed in the pack cover (150).

[0071] According to this configuration of the present invention, the thermal safety of the battery pack (10) can be improved. Since the nut (152) is coupled to the inner surface of the pack cover (150), the coupling strength between the melting bolt (400) and the pack cover (150) can be higher than the coupling strength between the melting bolt (400) and the partition wall (300). As a result, when a thermal event occurs in the battery module (200), the pack cover (150) and the partition wall (300) can be separated while the melting bolt (400) is coupled to the pack cover (150). Additionally, the pack cover (150) can swell while coupled to the melting bolt (400). As a result, the fastening hole (151) can remain sealed, and flames generated inside the battery pack (10) can be prevented from being exposed to the outside through the fastening hole (151). In addition, by sealing the fastening hole (151), external oxygen can be prevented from entering the interior of the battery pack (10).

[0072] Referring to FIGS. 6 and 7, the melting bolt (400) of the battery pack (10) according to one embodiment of the present invention may include a plastic material. By including a plastic material for the melting bolt (400), the bonding strength between the melting bolt (400) and the partition wall (300) may be reduced. Additionally, by including a plastic material for the melting bolt (400), it may melt easily.

[0073] According to this configuration of the present invention, the thermal safety of the battery pack (10) can be improved. When a thermal event occurs in the battery module (200), the melting bolt (400) melts or the connection between the melting bolt (400) and the partition wall (300) separates, thereby allowing the pack cover (150) of the pack case (100) to easily swell.

[0074] Referring to FIGS. 6 and 7, a melting bolt (400) of a battery pack (10) according to one embodiment of the present invention may include a melting bolt head (410) and a melting bolt body (420). The melting bolt body (420) may extend downward from the melting bolt head (410) or along the -Z axis direction. The melting bolt body (420) may have threads. The melting bolt body (420) may include a first part (421) and a second part (422). The first part (421) of the melting bolt body (420) may be a portion that passes through the pack cover (150) and the nut (152). The first part (421) of the melting bolt body (420) may extend from the melting bolt head (410). Additionally, the second part (422) of the melting bolt body (420) may extend downward from the first part (421) or along the -Z axis direction. The second part (422) of the melting bolt body (420) may be a part inserted into the partition wall (300). And the length (d1) of the first part (421) of the melting bolt body (420) may be formed to be longer than the length (d2) of the second part (422).

[0075] According to this configuration of the present invention, the thermal safety of the battery pack (10) can be improved. By forming the first part (421) of the melting bolt body (420) longer than the second part (422), the bonding strength between the melting bolt (400) and the pack cover (150) can be higher than the bonding strength between the melting bolt (400) and the partition wall (300). As a result, when a thermal event occurs in the battery module (200), the pack cover (150) and the partition wall (300) can be separated while the melting bolt (400) is bonded to the pack cover (150). Additionally, the pack cover (150) can swell while bonded to the melting bolt (400). As a result, the sealing of the fastening hole (151) formed in the pack cover (150) can be maintained.

[0076] Referring to FIGS. 6 and 7, the sum of the thickness (d3) of the pack cover (150) and the thickness (d4) of the nut (152) of a battery pack (10) according to one embodiment of the present invention may be formed to be longer than the depth (d2) of the insertion hole (301) formed in the partition wall (300). The sum of the thickness (d3) of the pack cover (150) and the thickness (d4) of the nut (152) may be configured to be substantially the same as the length (d1) of the first part (421) of the melting bolt body (420). Additionally, the depth (d2) of the insertion hole (301) formed in the partition wall (300) may be configured to be substantially the same as the length (d2) of the second part (422) of the melting bolt body (420).

[0077] According to this configuration of the present invention, the thermal safety of the battery pack (10) can be improved. The bonding strength between the melting bolt (400) and the pack cover (150) can be higher than the bonding strength between the melting bolt (400) and the partition wall (300). As a result, when a thermal event occurs in the battery module (200), the pack cover (150) and the partition wall (300) can be separated while the melting bolt (400) is bonded to the pack cover (150). Additionally, the pack cover (150) can swell while bonded to the melting bolt (400). As a result, the sealing of the fastening hole (151) formed in the pack cover (150) can be maintained.

[0078] FIG. 8 is a diagram showing a cross-sectional configuration along the cutting line A-A' of FIG. 1 when a thermal event occurs. Referring to FIGS. 6 through 8, a melting bolt (400) according to one embodiment of the present invention may be configured to melt when a thermal event occurs in a battery module (200). At this time, the melting bolt (400) may be configured so that the first part (421) and the second part (422) of the melting bolt body (420) are separated. Venting gas (g) may flow between the nut (152) and the partition wall (300) to melt the melting bolt (400). As a result, the first part (421) and the second part (422) of the melting bolt body (420) may be separated. And, as the lower part of the first part (421) of the melting bolt body (420) melts, the melting bolt (400) can seal the nut (152) more strongly. The second part (422), separated from the first part (421) of the melting bolt body (420), may be coupled to an insertion hole (301) formed in the partition wall (300).

[0079] According to this configuration of the present invention, the thermal safety of the battery pack (10) can be improved. By separating the first part (421) and the second part (422) of the melting bolt body (420), the sealing state of the fastening hole (151) formed in the pack cover (150) can be maintained.

[0080] FIG. 9 is a diagram showing a cross-sectional configuration along the cutting line A-A' of FIG. 1 when a thermal event occurs in the battery module (200). Referring to FIG. 9, a melting bolt (400) according to one embodiment of the present invention can be separated from the partition wall (300) when a thermal event occurs in the battery module (200). The pack cover (150) can be subjected to outward pressure by the venting gas (g). As a result, the connection between the second part (422) of the melting bolt body (420) and the insertion hole (301) formed in the partition wall (300) can be released, and the second part (422) of the melting bolt body (420) can be separated from the partition wall (300). The pack cover (150) can be inflated while maintaining a state of being connected to the melting bolt (400). At this time, the melting bolt (400) may have a longer pitch than a conventional bolt. As a result, the melting bolt (400) can be easily separated from the partition wall (300) when a thermal event occurs in the battery module (200).

[0081] FIG. 10 is a diagram showing a cross-sectional configuration along the cutting line B-B' of FIG. 1 when a thermal event occurs in the battery module (200). Referring to FIG. 10, when a thermal event occurs in the battery module (200), venting gas (g) can be discharged. The pressure caused by the venting gas (g) can push the pack cover (150) outward. As a result, the pack cover (150) can be separated from the first partition wall (310) of the partition wall (300) while maintaining a state of being combined with the melting bolt (400). Additionally, as the multiple melting bolts (400) and the first partition wall (310) of the partition wall (300) are separated, the pack cover (150) can be swollen overall. As a result, the space inside the battery pack (10) can be expanded. Additionally, the venting gas (g) can be discharged to the outside through the venting device (500). As a result, the explosion of the battery pack (10) can be prevented.

[0082] The battery pack (10) according to the present invention may further include various other components in addition to the battery module (200), such as a BMS, a busbar, a relay, a current sensor, etc., and various other components of the battery pack (10).

[0083] A battery pack (10) according to the present invention can be applied to a vehicle such as an electric vehicle or a hybrid vehicle. Referring to FIG. 11, an electric vehicle (600) according to the present invention may include a battery pack (10) according to the present invention. In addition, the vehicle (600) according to the present invention may further include various other components included in the vehicle in addition to the battery pack (10). For example, the vehicle (600) according to the present invention may further include a vehicle body, a motor, an electronic control unit (ECU), and other control devices.

[0084] As described above, although the present invention has been explained by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols

[0085] 100: Case 110: Base Plate 120: Sidewall 150: Pack Cover 151: Fastening hole 152: Nut 200: Battery module 210: Modular Case 211: Benting Hall 220: Battery cell 221: Storage compartment 222: 1st sealing section 223: Second sealing section 224: Electrode Lead 230: Busbar frame assembly 240: End cover 250: Pad 300: Partition Wall 301: Insertion hole 310: 1st Partition Wall 320: Second Partition Wall 400: Melting Bolt 410: Head 420: Body 421: Part 1 422: Part 2 500: Venting device

Claims

Claim 1 A battery pack comprising: a case providing an internal space and having a pack cover; a battery cell located inside the case; a partition wall dividing the internal space of the case; and a melting bolt connecting the pack cover and the partition wall, wherein the melting bolt is configured to melt at a specific temperature and further comprises a nut located between the pack cover and the partition wall, wherein the melting bolt comprises: a first part passing through the pack cover and the nut; and a second part extending from the first part and inserted into the partition wall, wherein the first part is formed to be longer than the second part. Claim 2 In claim 1, the battery pack is configured such that the melting bolt melts when a thermal event occurs in the battery cell. Claim 3 In claim 1, the melting bolt is a battery pack comprising a plastic material. Claim 4 delete Claim 5 In claim 1, the nut is a battery pack coupled to the inner surface of the pack cover. Claim 6 delete Claim 7 In claim 1, the melting bolt is configured such that the first part and the second part are separated when a thermal event occurs in the battery cell. Claim 8 A battery pack according to claim 1, wherein the partition wall has an insertion hole into which the melting bolt is inserted, and the sum of the thickness of the pack cover and the thickness of the nut is formed to be longer than the depth of the insertion hole. Claim 9 In claim 1, the melting bolts are provided in plurality, and the plurality of melting bolts are arranged along the longitudinal direction of the partition wall in a battery pack. Claim 10 A battery pack according to claim 1, further comprising a module case installed inside the case and accommodating the battery cell, wherein the module case has a venting hole facing the pack cover. Claim 11 An automobile comprising a battery pack of claim 1. Claim 12 A battery pack case comprising: a flat base plate; a side wall installed along the perimeter of the base plate on the upper surface of the base plate; a flat pack cover coupled to the upper surface of the side wall to form an internal space together with the base plate; a partition wall installed on the upper surface of the base plate to partition the internal space; and a melting bolt for fastening the pack cover and the partition wall, wherein the melting bolt is configured to melt at a specific temperature and further comprises a nut located between the pack cover and the partition wall, and the melting bolt comprises: a first part passing through the pack cover and the nut; and a second part extending from the first part and inserted into the partition wall, wherein the first part is formed to be longer than the second part. Claim 13 In claim 12, the above melting bolt is configured to melt when a thermal event occurs, in a battery pack case. Claim 14 In claim 12, the melting bolt is a battery pack case comprising a plastic material. Claim 15 delete Claim 16 delete Claim 17 In claim 12, the melting bolt is configured such that the first part and the second part are separated when a thermal event occurs. Claim 18 A battery pack including a battery pack case of claim 12.

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