Battery packs and vehicles containing them

Abstract

The battery pack according to the present invention may include a plurality of cell assemblies, a pack case having a housing space for housing the plurality of cell assemblies, and a discharge unit provided so as to be partially exposed on one side of the pack case, which discharges vent gas generated by thermal events in the cell assemblies to the outside of the pack case.

Description

Technical Field

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[0001] The present invention relates to a battery pack, and more particularly, to a battery pack capable of efficiently and quickly discharging vent gas and delaying heat propagation when a thermal event occurs in a battery module.

[0002] This application claims priority based on Korean Patent Application No. 10-2023-0086788 filed on July 4, 2023, and all the contents disclosed in the specification and drawings of the application are incorporated herein.

Background Art

[0003] A semi-permanent battery that can convert electrical energy into chemical energy and repeat charging and discharging is called a secondary battery, distinguished from a primary battery that cannot be reused once used.

[0004] In particular, lithium-ion secondary batteries have high energy density, can be lightweight and miniaturized, and have advantages such as excellent safety, low discharge rate, and long life. Therefore, in recent years, they have been actively used as batteries for electric vehicles. In addition, lithium-ion secondary batteries are generally classified into cylindrical, prismatic, pouch-type, etc. according to the manufacturing form, and their applications are not limited to electric vehicles, but cover a wide range such as energy storage systems (ESS: Energy Storage System) and other electrical equipment.

[0005] <00​​​​On the other hand, because rechargeable batteries involve chemical reactions during charging and discharging, their performance may degrade if used in environments exceeding the appropriate temperature. Furthermore, if thermal control at the appropriate temperature is not possible, there is always a possibility of unexpected ignition or explosion. In addition, battery packs, which are collections of rechargeable batteries, have a structure in which these batteries are densely housed inside the pack case, making them vulnerable to thermal events.

[0007] Therefore, if a thermal event such as overheating or thermal runaway occurs in a specific battery module, the vent gas and flames generated in that module can increase the internal pressure inside the battery pack, accelerating the accumulation of thermal energy and potentially leading to easy thermal propagation to adjacent battery modules. As a result, this could lead to a chain reaction of thermal runaway in battery modules and even the explosion of the entire battery pack.

[0008] In light of this background, research and development are actively being conducted on structures that effectively discharge vent gas generated by thermal events in the first battery module to the outside of the battery pack. In particular, in the case of automobiles, it is necessary to ensure that the discharge flow of vent gas is not obstructed by structures such as the vehicle body or chassis located adjacent to the battery pack, and to appropriately control the discharge of solid discharged material that is discharged along with the vent gas, so that the vent gas can be discharged smoothly and quickly before thermal energy from discharged material accumulates inside the battery pack. [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention has been made in view of the above-mentioned problems, and the problem that the present invention aims to solve is to provide a battery pack in which vent gas and the like are discharged in a direction that is not obstructed or blocked by structures such as the vehicle body or chassis located adjacent to the battery pack, and solid discharged material that may be discharged together with the vent gas is filtered during the discharge process, thereby enabling the vent gas to be discharged smoothly and quickly before the thermal energy from the discharged material accumulates inside the battery pack, and delaying the heat propagation phenomenon.

[0010] The technical problems that this invention aims to solve are not limited to those described above, and other problems not described will be clearly understood by those skilled in the art from the description of the invention below. [Means for solving the problem]

[0011] The battery pack according to the present invention may include a plurality of cell assemblies, a pack case having a housing space for housing the plurality of cell assemblies, and a discharge unit provided so as to be partially exposed on one side of the pack case, which discharges vent gas generated by thermal events in the cell assemblies to the outside of the pack case. The discharge unit may be configured to collect solid discharges discharged together with the vent gas and to discharge the vent gas to the outside. In other words, the discharge unit may be configured to separate solid discharges and vent gas from the discharges discharged from the cell assembly, collect the solid discharges, and discharge the vent gas to the outside. The discharge unit may be provided on the lower side of the pack case and configured to discharge the vent gas downward from the pack case. The cell assembly is arranged along the width and longitudinal directions within the storage space of the pack case, and the discharge unit may include at least one of a first discharge section provided on the peripheral edge of the lower surface of the pack case and a second discharge section provided along the width direction on the central region of the lower surface. For example, the discharge unit may include a first discharge section provided on the peripheral edge of the lower surface of the pack case. The discharge unit may include a second discharge section provided along the width direction on the central region of the lower surface. The discharge unit may include the first discharge section and the second discharge section. The pack case may include a pack frame provided with an open upper and lower end for housing the cell assemblies inside, and a lower frame portion positioned below the pack frame on which the plurality of cell assemblies are placed and which support the plurality of cell assemblies. The lower frame portion may include a base plate connected to the pack frame to support the cell assembly, and a bottom cover positioned on the lower surface of the pack case so as to cover the base plate. The first and second discharge sections may each include a discharge pipe positioned through the base plate and the bottom cover, and a vent valve connected to the discharge pipe and provided to be exposed on the outer surface of the bottom cover. The battery pack may further include a first mesh net positioned in the discharge pipe for collecting the solid discharge.

[0012] The lower frame portion further includes a bottom reinforcement bar provided between the bottom of the base plate and the bottom cover, and the base plate and the bottom cover have a plurality of through holes into which the discharge pipe is inserted, and the through holes may be formed in positions that are not interfered with by the bottom reinforcement bar. The base plate may be provided with a center beam that extends along the width direction of the cell assembly and separates adjacent cell assemblies in the longitudinal direction from each other. The center beam may have an "n" shape or a "square" shape in its longitudinal cross-section when viewed from the width direction of the cell assembly. The center beam may have discharge holes formed on both sides through which the vent gas is discharged. The discharge hole may be formed on the upper side of the side surface of the center beam. The second discharge section may further include a connecting pipe provided in contact with the inner wall of the center beam, with one end positioned adjacent to the discharge hole and the other end connected to the discharge pipe, and a plurality of second mesh nets arranged in the connecting pipe. A communication groove that communicates with the discharge hole may be formed on one side of the connecting pipe. The connecting pipe may include a first connecting section having a square cross-section, a second connecting section having a circular cross-section, and an axial pipe section connecting the first and second connecting sections and formed in a tapered shape with an inner diameter that gradually decreases along the axial direction. The solid discharge is collected by the first mesh net and the second mesh net, and the vent valve may be configured to discharge the vent gas. The first mesh network or the second mesh network may include two or more types of mesh with different mesh sizes. The cell assembly is housed in a module case to constitute a battery module, and the battery pack further includes a lateral partition wall that, together with the center beam, partitions the housing space for each battery module, and a top cover that can seal the housing space, and vent gas from any of the battery modules can be discharged to the outside of the battery pack through the first or second discharge section from each housing space without affecting other battery modules. The battery module may have top venting or side venting. The second discharge section may be inserted into the center beam. The discharge pipe may be positioned to avoid the flow path through which the coolant flow of the base plate, which can be integrated with the heat sink, is formed.

[0013] The path through which the vent gas is discharged via the first or second discharge section may be spatially completely separated from the area where cooling by the heat sink takes place.

[0014] The vent gas can be discharged to the outside of the battery pack via the exhaust pipe without diffusing into the space between the base plate and the bottom cover.

[0015] A hollow section can be formed within the transverse diaphragm, and a hole can be formed in the transverse diaphragm that communicates with the housing space, thereby enabling communication between the hollow section of the transverse diaphragm and the hollow section of the center beam. The vent gas can flow through the transverse diaphragm and be discharged to the outside of the battery pack through the second discharge section. The second discharge section may further include a baffle plate. According to the present invention, an automobile comprising one or more of the above-described battery packs may be provided. [Effects of the Invention]

[0016] According to one aspect of the present invention, vent gases generated by thermal events can be discharged downwards from the battery pack without being obstructed by structures such as the vehicle body or chassis located adjacent to the battery pack. When a thermal event occurs, vent gas may be generated from the cell assembly, and at this time, solid ejecta such as electrode fragments and spark particles may be discharged along with the vent gas. According to one aspect of the present invention, the solid ejecta and vent gas can be separated from each other, the solid ejecta can be collected, and the vent gas can be discharged to the outside of the battery pack. That is, the solid ejecta can be filtered during the vent gas discharge process. Therefore, vent gas and the like can be discharged smoothly and quickly before thermal energy caused by the ejecta accumulates inside the battery pack. By efficiently discharging the pressure and thermal energy inside the battery pack, the heat propagation phenomenon that propagates in a chain reaction to adjacent cell assemblies can be delayed.

[0017] According to one aspect of the present invention, solid discharges are collected and separated by multiple mesh screens of the discharge unit, and only vent gas can be discharged to the outside of the pack case, thereby minimizing the blockage phenomenon of the vent valve.

[0018] The effects of the present invention are not limited to the above-described effects. Even if there are effects not described, they can be clearly understood by those having ordinary knowledge in the technical field from this specification and the attached drawings.

[0019] The drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention to be described later. Therefore, the present invention is not construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic perspective view of a battery pack according to an embodiment of the present invention. [Figure 2] It is a schematic perspective view of a battery pack according to an embodiment of the present invention. [Figure 3] It is an exploded perspective view of the main components of the battery pack of FIG. 1. [Figure 4] It is an exploded perspective view of the main components of the battery pack of FIG. 1. [Figure 5] It is a longitudinal sectional view of the battery pack along the line A-A' of FIG. 2. [Figure 6] It is a bottom view of a battery pack according to an embodiment of the present invention. [Figure 7] It is a view showing the first discharge part in the discharge unit of a battery pack according to an embodiment of the present invention. [Figure 8] It is a view showing the second discharge part in the discharge unit of a battery pack according to an embodiment of the present invention. [Figure 9] It is a modification of FIG. 8. [Figure 10] It is a cutaway view of the center beam part of a battery pack according to an embodiment of the present invention. [Figure 11] It is a view schematically showing the vent gas discharge process of a battery pack according to an embodiment of the present invention. [Figure 12] This is a partially enlarged view of the first discharge section in Figure 11. [Figure 13] This is a partially enlarged view of the second discharge section in Figure 11. [Figure 14] This figure shows a modified version of part B in Figure 3. [Figure 15] This is another variation of Figure 8. [Figure 16] This is a diagram illustrating an automobile relating to one embodiment of the present invention. [Modes for carrying out the invention]

[0021] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Prior to this, terms and words used herein and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner and concept consistent with the technical idea of ​​the present invention, based on the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

[0022] Therefore, it should be understood that the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the invention, and that various equivalents and modifications may exist that can substitute for them at the time of filing.

[0023] The present invention may be implemented in a form in which each of the following embodiments is carried out independently. Alternatively, it may be implemented in a form in which multiple embodiments are combined. Each of the embodiments described below can be implemented not only individually, but also in any combination with each other.

[0024] Figures 1 and 2 are schematic perspective views of a battery pack according to one embodiment of the present invention, and Figure 3 is an exploded perspective view of the main components of the battery pack shown in Figure 1.

[0025] Referring to Figures 1 to 3, the battery pack 10 according to this embodiment may include a plurality of battery modules 100 corresponding to a plurality of cell assemblies. The battery pack 10 may include a pack case 200 in which a housing space S is formed for housing the plurality of battery modules 100. The battery pack 10 may include a discharge unit 300 for discharging vent gas generated by thermal events in the battery modules 100 to the outside of the pack case 200.

[0026] First, referring to Figure 1, the pack case 200 may include a pack frame 210. The pack case 200 may include a top cover (240) positioned on top of the pack frame 210. The pack case 200 may include a lower frame portion 220 positioned on bottom of the pack frame 210.

[0027] The pack case 200 can form the external appearance of the battery pack 10. The battery pack 10 may have a substantially rectangular parallelepiped appearance with a predetermined width and length in the width direction (X-axis) and longitudinal direction (Y-axis), and a predetermined height in the height direction (Z-axis). The bottom surface (XY plane) of the battery pack 10 may have a larger area than the sides. Such a battery pack 10 is a shape suitable for densely housing battery cells inside.

[0028] Referring to Figure 2, the discharge unit 300 may include a first discharge section 310 located on the lower surface of the pack case 200. The first discharge section 310 may be provided on the peripheral edge of the lower surface of the pack case 200. The first discharge section 310 may include a vent valve 313.

[0029] The discharge unit 300 may include a second discharge section 330 located on the lower surface of the pack case 200. The second discharge section 330 may be provided in the central region of the lower surface, along the width direction (X-axis direction). The second discharge section 330 may include a vent valve 333.

[0030] The discharge unit 300 may be provided so as to be partially exposed on one side of the pack case 200. As shown in the figure, the vent valve 313 of the first discharge section 310 may be provided so as to be exposed on the lower surface of the pack case 200. The vent valve 333 of the second discharge section 330 may be provided so as to be exposed on the lower surface of the pack case 200.

[0031] Referring to Figure 3, the battery pack 10 may include a battery module 100. The battery module 100 may be a type of cell assembly.

[0032] In this specification, a cell assembly may be a unit in which multiple battery cells are electrically connected. For example, a cell assembly may include a cell stack formed by stacking multiple battery cells and a busbar structure electrically coupled to the cell stack. For reference, a battery cell refers to a single completed rechargeable battery that can be repeatedly charged and discharged, and is not limited to shapes such as pouch-type batteries, cylindrical batteries, or prismatic batteries. Furthermore, a cell assembly corresponds to the concept of multiple such battery cells being assembled together. For example, a cell stack formed by bundling pouch-type batteries may be mechanically constrained and electrically connected by busbar frame assemblies at both the front and rear ends to constitute a single cell assembly.

[0033] One or more such cell assemblies can be housed in a module case 120 to form a battery module 100. In this embodiment, the cell assemblies configured as battery modules 100 are shown and described as being included in a battery pack 10. However, in order to increase the space utilization rate of the battery pack 10, if the battery pack is configured as a cell-to-pack structure, the cell assemblies may be directly incorporated into the pack case 200 without providing a module case 120.

[0034] Referring primarily to Figure 3, the battery module 100 may include a plurality of battery cells (not shown). The battery cells refer to secondary batteries including electrode assemblies, electrolytes, and pouch cases that house the electrode assemblies. In this embodiment, pouch-type battery cells with high energy density and easy stacking are targeted, but it goes without saying that cylindrical or prismatic secondary batteries can also be used as battery cells.

[0035] The pouch-type battery cell may include a pair of electrode leads (not shown) connected to the electrode assembly and extended outwards from the pouch case to function as electrode terminals. The pair of electrode leads may be extended forward and backward along the longitudinal direction, or they may be extended from both ends of the battery cell, i.e., in the longitudinal direction (±Y direction). If necessary, the electrode leads may be located only at one end in the Y-axis direction, for example, the -Y-axis end. Electrical components such as busbars, busbar frames, and module connectors may be mounted adjacent to the pair of electrode leads of such a battery cell, although these are not shown.

[0036] The battery module 100 may include a module case 120 for housing such battery cells. The module case 120 is configured to house one or more battery cells and may be made of a rigid and durable metal material or a plastic material such as ABS (Acrylonitrile Butadiene Styrene) resin to physically or chemically protect the housed battery cells. Terminals 140 of the battery module 100 may be provided on the front or rear side portions (both sides in the Y-axis direction) of such a module case 120. The terminals 140 may be either positive or negative and may be provided on both sides of the battery module 100, but may in some cases be located on only one side. Interbus bars (not shown) may be further connected to the terminals 140 for electrical connection between battery modules 100.

[0037] The battery module 100 may have an upper vent structure. For example, exhaust holes or exhaust slits may be formed on the upper surface of the module case 120 so that vent gas generated in the battery cells within the battery module 100 is discharged from the top of the battery module 100.

[0038] As another example, the battery module 100 may have a side vent structure. Discharge holes or slits may be formed on the side of the module case 120 so that vent gas generated in the battery cells within the battery module 100 is discharged from the side of the battery module 100.

[0039] As shown in Figure 3, the pack case 200 can accommodate multiple battery modules 100. Therefore, the pack case 200 may have an internal storage space S for accommodating multiple battery modules 100. The battery modules 100 can be arranged within the storage space S of the pack case 200 along the width direction (X-axis direction) and the longitudinal direction (Y-axis direction). On the other hand, the pack case 200 is a component for protecting the battery modules 100 from external impacts, and may be made of a material with excellent mechanical rigidity.

[0040] In Figure 3, the pack case 200 is shown disassembled into a top cover 240, a pack frame 210, and a lower frame portion 220. The pack case 200 can be constructed by connecting the pack frame 210 and the lower frame portion 220 to each other, so that the bottom surface of the pack case 200 becomes the top surface of the lower frame portion 220. The pack frame 210 and the lower frame portion 220 can be connected to each other to form a pack tray. The upper end of the pack tray is open and can be connected to the top cover 240. When the pack tray and the top cover 240 are connected to each other, various joining processes such as bolting, welding, bonding, and hooking can be applied for sealing.

[0041] The pack frame 210 may be provided with a lateral bulkhead 211 in the lateral direction (Y-axis direction) that partitions the interior. The pack frame 210 may be provided with a lateral center beam 212 in the lateral direction (X-axis direction) that partitions the interior. Here, the center beam 212 may be positioned in the center of the accommodation space S and extending along the width direction (X-axis direction) of the battery module 100. The lateral bulkhead 211 and the center beam 212 can partition and separate a plurality of battery modules 100.

[0042] Discharge holes 213 may be formed along the side of the center beam 212. A discharge unit 300 may be inserted into the center beam 212, and vent gas and the like in the containment space S can be discharged through the discharge unit 300. The vent gas may include electrolyte gas generated in the battery cell and gas produced by the flame. When the vent gas is ejected, solid ejecta such as electrode fragments and spark particles may also be ejected. The internal space of the center beam 212 can provide a discharge path for the vent gas and solid ejecta.

[0043] Referring primarily to Figure 3, the lower frame portion 220 forms the bottom surface of the pack case 200, and multiple through holes H1, H2 (see Figure 4) may be formed in the lower frame portion 220. The lower frame portion 220 is composed of a multilayer laminated structure consisting of a base plate 221 and a bottom cover 223, as will be described in detail later, and the through holes H1, H2 may be formed in both the base plate 221 and the bottom cover 223.

[0044] The discharge unit 300 may be coupled to through holes H1 and H2. The discharge unit 300 may be provided so as to be partially exposed on one side of the pack case 200. The discharge unit 300 can discharge vent gas generated by thermal events in the battery module 100 inside the pack case 200 to the outside of the pack case 200. As an example, as shown in Figure 2, the discharge unit 300 may be provided on the lower surface of the pack case 200 and configured to discharge vent gas downward from the pack case 200. The discharge unit 300 may be inserted into the lower frame portion 220 and configured so as to be partially exposed on the lower surface of the pack case 200.

[0045] Referring to Figure 3, it is shown that a discharge pipe 311 is connected to a through hole H1 located along the periphery of the lower frame portion 220, and a connecting pipe 335 is located in a through hole H2 located along the width direction of the battery module 100 in the central region of the lower frame portion 220. A communication groove 336 may be formed on one side of the connecting pipe 335. These discharge pipes 311 and connecting pipes 335 will be described later.

[0046] Such a discharge unit 300 can be configured such that vent gas generated in the storage space S of the pack case 200 is discharged through the lower frame portion 220 and then discharged to the outside through a plurality of vent valves 313, 333 provided on the lower surface of the pack case 200 as shown in Figure 2. This allows the vent gas and the like to be discharged downwards, in a direction that is not obstructed or blocked by structures such as the vehicle body or chassis located adjacent to the battery pack 10.

[0047] To explain in more detail, in the case of automobiles, the battery pack 10 is usually installed at the bottom of the vehicle body, and the cabin where the occupants sit and live is generally located above the battery pack 10, so it is not easy to discharge the vent gas upwards. In addition, in the width direction (X-axis direction) of the battery module 100, in the overall length direction of the automobile, the layout of the vehicle body and chassis and other structures may cause turbulence in the airflow, which may prevent the smooth discharge of the vent gas.

[0048] On the other hand, since there are relatively few obstacles on the lower side of the battery pack 10, the discharge unit 300 according to this embodiment can discharge vent gas downward through the lower surface of the pack case 200. This allows vent gas and other substances to be discharged smoothly and quickly before heat energy accumulates inside the battery pack 10 due to the discharged material.

[0049] Furthermore, the number of discharge paths can be increased compared to conventional designs. Specifically, when discharge is directed in the direction of the vehicle's overall length, which corresponds to the width direction of the battery module 100, the area constraints on the sides of the battery pack 10 make it difficult to expand the discharge paths, and as a result, the number of discharge paths is inevitably limited. In contrast, when the entire bottom surface of the pack case 200 is utilized, the number of discharge paths can be easily increased. This is because the bottom surface of the pack case 200 has a relatively large area. In this embodiment, it is possible to increase the number of discharge paths and vent valves to more than double that of conventional designs, improving discharge efficiency and delaying the heat propagation phenomenon in which heat is transmitted in a chain reaction to adjacent battery modules within the battery pack.

[0050] Furthermore, according to the above-described embodiment, in situations such as thermal runaway, it is possible to effectively prevent high-temperature gases or flames from moving towards the upper side of the battery pack 10. In particular, when occupants are located on the upper side of the battery pack 10, such as in electric vehicles, according to the above-described embodiment, it is possible to suppress or delay the movement of gases or flames towards the occupants. This ensures the safety of the upper side of the battery pack 10 while also freeing the user from layout structures and other constraints that may be required when mounting the battery pack 10 in a vehicle.

[0051] The following provides a more detailed explanation of Pack Case 200.

[0052] Referring again to Figure 3, the pack frame 210 may be configured as a rectangular frame. The pack frame 210 may be configured with an open upper and lower end. A top cover 240 may be placed at the upper end of the pack frame 210, and a lower frame portion 220 may be placed at the lower end. This allows the pack frame 210 to form a housing space S for housing the battery module 100 inside.

[0053] Figure 4 is an exploded perspective view of the main components of the battery pack shown in Figure 1, and Figure 5 is a longitudinal cross-sectional view of the battery pack along the line A-A' in Figure 2.

[0054] Referring primarily to Figures 2 and 5, the pack frame 210 may be provided with lateral bulkheads 211 in the lateral direction (Y-axis direction) that partition the interior. The lateral bulkheads 211 are arranged along the longitudinal direction (Y-axis direction), but may be spaced apart by the width of the battery module 100.

[0055] The pack frame 210 may be provided with a vertical (X-axis direction) center beam 212 that partitions the interior. The center beam 212 may be positioned extending in the width direction (X-axis direction) in the central part of the pack frame 210 and configured to partition adjacent battery modules 100 in the longitudinal direction. When viewed from the width direction of the battery modules 100, the vertical cross-section of the center beam 212 may be formed in the shape of an "n" or a "square", and the interior of the center beam 212 may be a hollow structure, forming a hollow portion 214. In this embodiment, as shown in Figure 5, the center beam 212 may be "n" shaped with an open lower end. On the other hand, if the vertical cross-section of the center beam 212 is "n" shaped, the lower frame portion 220 may be connected to the open surface at its lower end, making it "square". Wiring and other electrical units may be inserted into the hollow portion 214 of such a center beam 212.

[0056] Multiple discharge holes 213 may be formed on both side surfaces of such a center beam 212. Through the discharge holes 213, vent gas or the like in the containment space S can be discharged into the hollow portion 214 inside the center beam 212. The discharge holes 213 may be formed on the upper side of the side surface of the center beam 212.

[0057] In this embodiment, five transverse bulkheads 211 and one center beam 212 are provided inside the pack frame 210, and ten battery modules 100 are housed in the housing space S. However, the scope of the present invention is not limited to the number of transverse bulkheads 211 and center beam 212 or the number of battery modules 100 housed in this embodiment.

[0058] Referring again to Figures 1 to 3, the top cover 240 may be positioned on top of the pack frame 210 and configured to seal the housing space S in which the battery modules 100 are housed. In this embodiment, the top cover 240 may be configured to completely cover the 10 battery modules 100. The top cover 240 may be made of a material such as aluminum or SUS to ensure rigidity and to be composed of a highly conductive material. There may or may not be a gap between the lower surface of the top cover 240 and the upper surface of the battery modules 100.

[0059] There may or may not be a gap between the upper surfaces of the transverse bulkhead 211 and the center beam 212 and the lower surface of the top cover 240. For example, if the upper surfaces of the transverse bulkhead 211 and the center beam 212 are in contact with the lower surface of the top cover 240 and there is no gap between them, each battery module 100 can be completely enclosed by the transverse bulkhead 211, the center beam 212 and the top cover 240, and isolated from other battery modules 100. That is, the housing spaces S may be separated and isolated from each other according to the number of battery modules 100, and gases generated from any battery module 100 may be discharged from their respective housing spaces S to the outside of the battery pack 10 without affecting other battery modules 100.

[0060] The lower frame portion 220 is located at the bottom of the pack frame 210 and is the portion on which the multiple battery modules 100 are mounted and supported. Referring mainly to Figure 4, the lower frame portion 220 may include a base plate 221 which is coupled to the pack frame 210 and supports the battery modules 100. The lower frame portion 220 may include a lower reinforcing bar 222 which is provided between the bottom of the base plate 221 and the bottom cover 223. The lower frame portion 220 may include a bottom cover 223 which is positioned on the lower surface of the pack case 200 so as to cover the base plate 221.

[0061] The base plate 221 can be coupled to the lower part of the pack frame 210. Referring primarily to Figure 5, the base plate 221 can be coupled to a stepped portion provided at the lower part of the pack frame 210. The base plate 221 can form the bottom surface of the pack case 200 and be positioned opposite the bottom of the multiple battery modules 100 housed in the storage space S. This allows the multiple battery modules 100 to be stably mounted and supported.

[0062] On the other hand, although not shown, the bottom surface of the base plate 221 may be provided with channels through which multiple coolant flows are formed, and the base plate 221 and the cooling structure may be integrated into one unit. For example, the base plate 221 may be integrated with a heat sink.

[0063] Referring primarily to Figures 4 and 5, the lower reinforcing bar 222 may be provided between the bottom of the base plate 221 and the bottom cover 223. The lower reinforcing bar 222 may be configured to directly contact the bottom of the base plate 221. The lower reinforcing bar 222 can support the base plate 221 from below and structurally reinforce it, preventing phenomena such as bending or warping of the base plate 221. Multiple such lower reinforcing bars 222 may be provided.

[0064] The lower reinforcing bars 222 may be provided at positions corresponding to the five transverse bulkheads 211. The lower reinforcing bars 222 may be provided at positions perpendicular to the center beam 212.

[0065] The bottom cover 223 may be positioned on the underside of the pack case 200 so as to cover the base plate 221. As shown in Figure 5, the bottom cover 223 may be positioned opposite the lower end of the pack frame 210 and spaced apart from the base plate 221 and the lower reinforcing bar 222.

[0066] As shown in Figure 4, a plurality of through holes H1 and H2 may be formed in such a lower frame portion 220. That is, the base plate 221 and the bottom cover 223 are provided with a plurality of through holes H1 and H2 into which discharge pipes 311 and 331 can be inserted, and the through holes H1 and H2 may be formed in positions that do not interfere with the lower reinforcing bar 222. The through holes H1 and H2 formed in the base plate 221 and the through holes H1 and H2 formed in the bottom cover 223 may be arranged in alignment along the Z-axis direction. Discharge pipes 311 and 331 can be inserted between the through holes H1 and H2 that are aligned in the Z-axis direction, respectively.

[0067] The exhaust pipes 311 and 331 may be positioned to avoid the flow path through which the coolant flow of the base plate 221, which can be integrated with the heat sink, is formed. In this case, the exhaust of vent gas and the cooling of the battery pack are spatially completely separated within the lower frame section 220. By utilizing the exhaust pipes 311 and 331 rather than simply placing the vent valves 313 and 333 on the underside of the pack case 200, the vent gas can be quickly discharged to the outside of the battery pack 10 via the exhaust pipes 311 and 331 without diffusing into the space between the base plate 221 and the bottom cover 223 when venting downwards.

[0068] The discharge pipes 311 and 331 may also be positioned within the flow path where the coolant flow of the base plate 221, which can be integrated with the heat sink, is formed. This allows the vent gas discharged through the discharge pipes 311 and 331 to be discharged at a reduced temperature during the discharge process. In this case, seals are provided at the connection points between the discharge pipes 311 and 331 and the through holes H1 and H2 to prevent coolant leakage from the flow path.

[0069] The discharge unit 300 will be explained in more detail below.

[0070] Figure 6 is a bottom view of a battery pack according to one embodiment of the present invention, Figure 7 is a diagram showing the first discharge section in the discharge unit of the battery pack according to one embodiment of the present invention, Figure 8 is a diagram showing the second discharge section in the discharge unit of the battery pack according to one embodiment of the present invention, and Figure 9 is a modified example of Figure 8. Figure 10 is a cross-sectional view of the center beam section of the battery pack according to one embodiment of the present invention.

[0071] Referring to Figures 6 to 10, along with Figures 2 to 4, the discharge unit 300 may include at least one of a first discharge section 310 and a second discharge section 330 located on the lower surface of the pack case 200. In this embodiment, an example is shown that includes both the first discharge section 310 and the second discharge section 330.

[0072] As primarily shown in Figure 6, the first discharge section 310 may be provided on the periphery of the lower surface of the pack case 200. In the figure, the vent valve 313 of the first discharge section 310 is shown in the front view, and the first discharge section 310 may communicate with the housing space S. The second discharge section 330 may be provided on the central region of the lower surface along the width direction (X-axis direction). Similarly, in the figure, the vent valve 333 of the second discharge section 330 is shown, and it may communicate with the hollow portion 214 of the center beam 212. The second discharge section 330 may be inserted into the center beam 212. As shown in Figure 6, multiple second discharge sections 330 may be arranged in parallel along the center beam 212. One second discharge section 330 may function in common for both the battery module on the left and the battery module on the right side with respect to the center beam 212. The second discharge section 330 is positioned so as not to be interfered with by the lower reinforcing bar 222, and its number is not limited to the example shown in Figure 6, but can be changed as needed.

[0073] The first discharge section 310 can be provided on the periphery of the lower surface of the pack case 200, and by utilizing the entire lower surface of the pack case 200, the number of discharge paths can be easily increased. For example, compared to providing two vent valves on each side of the front and rear surfaces of the pack case 200, resulting in four vent valves per battery pack 10, in this embodiment, since the bottom surface of the pack case 200 has a relatively large area, it is possible to provide 16 vent valves, for example, 313. This dramatically increases the number of vent valves, improves discharge efficiency, and delays the heat propagation phenomenon that propagates in a chain reaction to adjacent battery modules. At least one first discharge section 310 can be provided for each storage space S. However, the placement and number of the first discharge sections 310 are not limited to the example shown in Figure 6 and can be changed as desired.

[0074] Referring primarily to Figures 5 and 7, the first discharge section 310 may include a discharge pipe 311, a first mesh net 312 positioned, for example, in the middle of the discharge pipe 311, and a vent valve 313 provided at one end of the discharge pipe 311.

[0075] The discharge pipe 311 can be connected to through holes H1 formed in the base plate 221 and the bottom cover 223, respectively. This allows the discharge pipe 311 to be positioned to penetrate the base plate 221 and the bottom cover 223. The discharge pipe 311 may be a pipe shape with a circular cross-section. This allows the storage space S of the pack case 200 and the outside of the pack case 200 to communicate with each other via the discharge pipe 311.

[0076] A first mesh screen 312 may be placed in such a discharge pipe 311. The first mesh screen 312 may be positioned perpendicular to the discharge flow of the discharge pipe 311 (or the longitudinal orientation of the discharge pipe 311). This allows solid discharge material moving along the discharge pipe 311 to be smoothly filtered and collected by the first mesh screen 312.

[0077] The first mesh net 312 may be fitted into a ring-shaped groove provided in the inner wall of the discharge pipe 311. The discharge pipe 311 and the first mesh net 312 may be manufactured by insert injection molding. In order to fix the first mesh net 312 to the inner wall of the discharge pipe 311, the inner wall of the discharge pipe 311 may be provided with a projection (not shown) that protrudes toward the center.

[0078] The first mesh 312 may include two or more types of mesh with different mesh sizes. Mesh with relatively larger mesh sizes may be positioned above the Z-axis than mesh with relatively smaller mesh sizes. Two or more different types of mesh may be positioned in contact with each other. Two or more different types of mesh may also be positioned spaced apart. Two or more different types of mesh may constitute a single unit component, and by attaching this unit component to the discharge pipe 311, the structure shown in Figure 7 can be realized. When the vent gas inside the battery pack 10 flows into the discharge pipe 311 and moves downward, the configuration may be such that large solid discharges are first filtered by the mesh with relatively larger mesh sizes, small solid discharges are secondarily filtered by the mesh with relatively smaller mesh sizes, and then only gas is discharged.

[0079] The vent valve 313 is provided at one end of the discharge pipe 311 and can be connected to the discharge pipe 311. The vent valve 313 may also be provided so as to be exposed on the outer surface of the bottom cover 223. The vent valve 313 opens when the pressure exceeds a predetermined level, allowing for selective opening and closing of the housing space S of the pack case 200 and the outside of the pack case 200. The discharge direction of the vent valve 313 may be directed downwards from the pack case 200. The vent valve 313 may be normally closed, open when the pressure exceeds a predetermined level to discharge gas from inside the battery pack 10, and close again when the pressure drops.

[0080] Thus, the vent gas generated inside the battery module 100 flows into the discharge pipe 311, and after solid discharge is filtered by the first mesh screen 312, it can be discharged to the outside of the battery pack 10 through the vent valve 313, downwards through the pack case 200. Referring mainly to Figure 8, the second discharge section 330, like the first discharge section 310, is configured to include a discharge pipe 331, a first mesh screen 332, and a vent valve 333, and may further include a connecting pipe 335 and a second mesh screen 337.

[0081] The connecting pipe 335 may be a part that guides the vent gas discharged to the center beam 212 to be smoothly discharged downward to the pack case 200 via the vent valve 333 of the second discharge section 330. For this reason, the connecting pipe 335 may be provided such that one end is connected to the discharge pipe 331 and the other end abuts against the bottom wall on the upper side of the center beam 212. In addition, a communication groove 336 communicating with the discharge hole 213 may be formed on one side of the connecting pipe 335.

[0082] Specifically, the connecting pipe 335 may include a first connecting section 335a, a second connecting section 335b having a circular cross-section, and an axial pipe section 335c.

[0083] The first connecting section 335a may refer to the upper region of the connecting pipe 335 in Figure 8. Referring to Figure 10, the first connecting section 335a may have a rectangular cross-section and its outer surface may be positioned facing the inner side wall of the center beam 212. By configuring the first connecting section 335a to correspond to the internal shape of the center beam 212 in this way, the hollow space 214 of the center beam 212 can be utilized to the fullest extent, and the discharge of a large amount of vent gas becomes easier. In addition, a communication groove 336 is formed in the first connecting section 335a, and the communication groove 336 may be positioned to communicate with the discharge hole 213. The communication groove 336 may be substantially the same size as the discharge hole 213. This minimizes the flow of vent gas, etc., into other hollow parts 214 of the center beam 212 instead of into the connecting pipe 335, and the occurrence of leakage phenomena can also be minimized.

[0084] The second connecting section 335b refers to one end of the connecting pipe 335 connected to the discharge pipe 331, and may be provided in the lower region of the connecting pipe 335 in the drawing. The second connecting section 335b may be made of a pipe material with a circular cross-section, and the inner diameter of the second connecting section 335b may be set to be substantially the same as the inner diameter of the discharge pipe 331. By making the second connecting section 335b circular, alignment, connection, or assembly with the discharge pipe 331 can be performed smoothly.

[0085] Figure 9 is a modified example of Figure 8. Referring to Figure 9, the inner diameter of the second connecting section 335b is smaller than the inner diameter of the discharge pipe 331, and it has a length that extends downward from the base plate 221. The second connecting section 335b and the discharge pipe 331 are assembled by press-fitting the second connecting section 335b into the inside of the discharge pipe 331. A sealing member 338 is further applied to the connection portion between the second connecting section 335b and the discharge pipe 331 to prevent gas leakage at the connection portion.

[0086] Referring to Figures 8 and 9, the axial pipe section 335c can connect the first connecting section 335a and the second connecting section 335b to each other. The axial pipe section 335c is formed in a tapered shape with an inner diameter that gradually decreases along the axial direction, so that the discharge flow of vent gas can be maintained without obstruction even as the inner diameter decreases between the first connecting section 335a and the second connecting section 335b.

[0087] The second mesh net 337 can be arranged inside the connecting pipe 335, mainly referring to Figures 8 to 10. Multiple second mesh nets 337 can be provided inside the connecting pipe 335. For example, in this embodiment, two second mesh nets 337 can be provided, with one second mesh net 337a arranged in the first connecting section 335a and the other second mesh net 337b arranged in the second connecting section 335b. Such multiple second mesh nets 337 can further improve the collection efficiency of solid discharged material. On the other hand, in Figure 10, for the sake of explanation, a part of the second mesh net 337 is omitted from the illustration.

[0088] The second mesh screens 337a and 337b may have the same mesh size, or the second mesh screen 337a may have a larger mesh size than the second mesh screen 337b. In this way, by positioning the second mesh screen 337a, which has a relatively larger mesh size, above the second mesh screen 337b, which has a relatively smaller mesh size, when the vent gas inside the battery pack 10 flows into the connecting pipe 335 and moves downward, larger solid discharges are first filtered by the second mesh screen 337a, which has a relatively larger mesh size, then smaller solid discharges are secondarily filtered by the second mesh screen 337b, which has a relatively smaller mesh size, and finally filtered again by the first mesh screen 332, so that only gas can be discharged.

[0089] Through the second discharge section 330 configured in this way, vent gas generated in the internal space of the battery module 100 is released into the containment space S via the side vents or top vents of the battery module 100, and then flows into the connecting pipe 335 via the discharge hole 213 of the center beam 212 and the communication groove 336, where it can be guided and moved downward. At this time, the vent gas is discharged into the interior of the connecting pipe 335 via the communication groove 336 which is arranged to communicate with the discharge hole 213, and does not move into other cavities of the center beam 212. The vent gas that has moved downward can pass through the discharge pipe 331 and the first mesh net 332 and finally be discharged to the bottom of the pack case 200 via the vent valve 333. The vent valve 333 may be structured to be normally closed, open when the pressure exceeds a certain level to discharge gas from inside the battery pack 10, and close again when the pressure drops.

[0090] The second mesh net 337 may be fitted into a ring-shaped groove provided in the inner wall of the connecting pipe 335. The connecting pipe 335 and the second mesh net 337 may be manufactured by insert injection molding. In order to fix the second mesh net 337 to the inner wall of the connecting pipe 335, the inner wall of the connecting pipe 335 may be provided with a projection (not shown) that protrudes toward the center.

[0091] In this way, the vent gas generated inside the battery module 100 flows into the center beam 212, flows through the connecting pipe 335 and the discharge pipe 331, is filtered by the second mesh screen 337 and the first mesh screen 332, and can then be discharged to the outside of the battery pack 10 through the vent valve 333 to the bottom of the pack case 200.

[0092] The discharge holes 213 of the center beam 212 may also be formed on the upper side of the aforementioned side surface of the center beam 212. This allows the vent gas, including solid discharges and gases, to move through a zigzag discharge path in the height direction of the battery module 100, utilizing the entire height space of the center beam 212, thereby ensuring a sufficiently long discharge path. This point will be described in detail in the subsequent explanation of the discharge process.

[0093] In this configuration, vent gases generated by thermal events can be discharged downwards from the battery pack 10 without being obstructed or blocked by structures such as the vehicle body or chassis located adjacent to the battery pack 10. Furthermore, in this configuration, solid discharges can be filtered during the discharge process.

[0094] Therefore, vent gas and other substances can be smoothly and quickly discharged before heat energy accumulates inside the battery pack 10 due to discharged material. By efficiently discharging the pressure and heat energy inside the battery pack 10, the heat propagation phenomenon that propagates in a chain reaction to adjacent battery modules 100 can be delayed.

[0095] Furthermore, the multiple mesh nets of the discharge unit 300 collect and separate solid discharge materials, including electrode discharges and spark particles, so that only vent gas can be discharged outside the pack case 200, thereby minimizing the blockage phenomenon of the vent valves 313 and 333.

[0096] Figure 11 is a schematic diagram showing the vent gas discharge process of a battery pack according to one embodiment of the present invention, and Figures 12 and 13 are enlarged partial views of the first and second discharge sections in Figure 11, respectively.

[0097] The discharge process by which the vent gas according to this embodiment is easily discharged to the outside will be described in detail below with reference to Figures 11 to 13.

[0098] First, when a thermal event occurs in a specific battery module 100 as shown in Figure 11, and the top or side vent is activated, the internal pressure in the containment space S increases, generating a large amount of vent gas and solid discharge within the containment space S.

[0099] Next, the vent gas and solid discharges move along the longitudinal direction of the battery module 100, as shown in Figure 11, toward the first discharge section 310 or the second discharge section 330. The vent gas and other discharges that have moved toward the first discharge section 310 move downward via the discharge pipe 311, as shown in Figure 12. During this movement, the solid discharges are collected by the first mesh net 312, and mainly only the gas can be discharged downwards from the pack case 200. This can reduce the internal pressure of the battery pack 10 or reduce the rate at which the internal pressure rises. Since the rate of heat transfer decreases as the rise in internal pressure is mitigated, the heat transfer delay performance can be improved according to the present invention.

[0100] Furthermore, the vent gas and other materials that have moved to the second discharge section 330 are discharged from the discharge hole 213 of the center beam 212 and introduced into the connecting pipe 335 via the connecting groove 336 that communicates with it. In this process, as shown in Figure 13, the solid discharge material and vent gas may form a discharge flow through a zigzag path in the height direction of the battery module 100. That is, when the solid discharge material rises to the height of the discharge hole 213 and is introduced into the connecting pipe 335 via the connecting groove 336, detachment of the solid discharge material may occur. Then, as it is guided downward by the connecting pipe 335 and discharged, the solid discharge material is collected by multiple second mesh screens 337, and then filtered by the first mesh screen 332 of the discharge pipe 331, so that finally only the vent gas can be discharged downwards from the pack case 200. Compared to the first discharge section 310, the movement path of the vent gas in the second discharge section 330 is formed in a zigzag pattern, and the movement path may be longer. Furthermore, as the vent gas travels along a longer path, multiple second mesh screens 337 perform filtering and collection processes during the process, which can further improve the collection efficiency of solid discharges.

[0101] According to this embodiment, the vented gas vented to the side or top of each module can be moved into the center beam 212 and then vented downward through the second discharge section 330. This can reduce the internal pressure of the battery pack 10 or reduce the rate at which the internal pressure rises. Since the rate of heat transfer decreases as the rise in internal pressure is mitigated, the heat transfer delay performance can be improved according to the present invention.

[0102] As described above, each battery module 100 can be completely enclosed by a lateral bulkhead 211, a center beam 212, and a top cover 240, and isolated from other battery modules 100. That is, each housing space S is isolated from each other, and vent gas generated from any of the battery modules 100 can be discharged downward through the first discharge section 310 and the second discharge section 330 in the housing space S in which the battery module 100 is located. Therefore, even if thermal runaway occurs in a single battery module, it is possible to minimize the impact on other normal battery modules inside the battery pack 10, and vent gas can be discharged in a timely manner, so that high-temperature vent gas does not accumulate inside the battery pack 10 and cause heat buildup, and while vent gas is discharged, damage to other battery modules in the battery pack 10 can also be effectively prevented.

[0103] On the other hand, Figure 14 shows a modified version of part B in Figure 3.

[0104] Referring to Figure 14, it is also possible to form a hollow section 211a within the transverse bulkhead 211, a hole 211b in the transverse bulkhead 211 that communicates with the containment space S, and to connect the hollow section 211a of the transverse bulkhead 211 with the hollow section 214 of the center beam 212. In this case, the vent gas in the containment space S flows into the hollow section 211a of the transverse bulkhead 211 through the hole 211b, moves through the hollow section 211a inside the transverse bulkhead 211, flows into the hollow section 214 of the center beam 212 which is in communication with it, and can be vented downward through the second discharge section 330 connected thereto. When using large capacity battery cells, it is important to ensure the length of the vent path. According to this configuration, although the second discharge section 330 is provided at the bottom of the pack case 200, the vent path can be ensured to be of sufficient length through the inside of the center beam 212, or through the inside of the center beam 212 and the transverse bulkhead 211.

[0105] With this configuration, vent gases and other substances generated by thermal events can be discharged downwards from the battery pack 10 without being obstructed or blocked by structures such as the vehicle body or chassis located adjacent to the battery pack 10. Furthermore, solid discharges can be filtered during the discharge process. Therefore, vent gases and other substances can be discharged smoothly and quickly before thermal energy accumulates inside the battery pack 10 due to the discharges. By efficiently discharging the pressure and thermal energy inside the battery pack 10, the heat propagation phenomenon that propagates in a chain reaction to adjacent battery modules 100 can be delayed.

[0106] Furthermore, the multiple mesh screens 312, 332, and 337 of the discharge unit 300 collect and separate electrode discharges and solid discharges including spark particles, so that only vent gas can be discharged outside the pack case 200, thereby minimizing the blockage phenomenon of the vent valves 313 and 333.

[0107] Figure 15 is another variation of Figure 8.

[0108] Referring to Figure 15, the second discharge section 330 may include a baffle plate 339 within the connecting pipe 335. The baffle plate 339 may be located above the second mesh net 337. The vent gas flowing into the connecting pipe 335 via the communication groove 336 may first collide with the baffle plate 339. The baffle plate 339 can prevent swirling flow and backflow within the communication groove 336. The baffle plate 339 may be a plate-like body with a shield structure provided perpendicular to the longitudinal direction of the connecting pipe 335, as shown in the figure. The baffle plate 339 may be in the form of a disc, a donut-shaped plate, or a crescent-shaped plate with multiple holes. The baffle plate 339 can prevent electrode fragments and spark particles that flow in with the vent gas from returning to the containment space S via the communication groove 336.

[0109] The baffle plate 339 may be fitted into a ring-shaped groove provided in the inner wall of the connecting pipe 335. The connecting pipe 335 and the baffle plate 339 may be manufactured by insert injection molding. To fix the baffle plate 339 to the inner wall of the connecting pipe 335, the inner wall of the connecting pipe 335 may be provided with a projection (not shown) that protrudes toward the center.

[0110] By further including the baffle plate 339 in this way, the vent gas and solid discharged material that flows into the connecting pipe 335 will not be ejected in all directions and upward, thus preventing damage not only to the battery module where the incident occurred but also to surrounding battery modules.

[0111] On the other hand, the battery pack 10 according to the present invention may further include various devices for controlling the charging and discharging of the battery module 100, such as a battery management system (BMS), a current sensor, a fuse, etc., although these are not shown in the figures.

[0112] Figure 16 is a diagram illustrating an automobile according to one embodiment of the present invention.

[0113] Referring to Figure 16, the battery pack 10 according to the present invention is applicable to automobiles such as electric vehicles and hybrid vehicles. That is, the automobile V according to the present invention may include the battery pack 10 according to the present invention. The battery pack 10 can be installed in the vehicle frame located below the vehicle seats or in the trunk space, and when mounted in the vehicle, the arrangement order of the battery pack 10 can be reversed as needed.

[0114] In this specification, terms indicating directions such as up, down, left, right, front, and back are used, but these terms are for convenience of explanation and it will be obvious to those skilled in the art that they may change depending on the position of the object in question, the position of the observer, etc.

[0115] Although the present invention has been described above based on limited embodiments and drawings, it goes without saying that the present invention is not limited thereto, and that various modifications and variations are possible within the equivalent scope of the technical idea of ​​the present invention and the appended claims by persons with ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0116] V Automobile 10 Battery Packs 100 Battery Modules 120 Module Case Terminal 140 200 pack case S Containment space 210 Pack Frame 211 Transverse bulkhead 212 Center beam 220 Lower frame section 221 Base Plate H through hole 222 Lower reinforcement bar 223 Bottom Cover 240 Top Cover 300 discharge units 310 1st discharge section 311 Discharge pipe 312, 332 First Mesh Network 313 Vent valve 330 2nd discharge section 331 Discharge pipe 333 Vent valve 335 Connecting pipe 335a First connecting section 335b Second connecting section 335c Axle tube section 336 Communication groove

Claims

1. Multiple cell assemblies, A pack case having a storage space formed in which the plurality of cell assemblies are housed, A discharge unit is provided so as to be partially exposed on one side of the pack case and discharges vent gas generated by thermal events in the cell assembly to the outside of the pack case, Includes a battery pack.

2. The battery pack according to claim 1, wherein the discharge unit is configured to collect solid discharged together with the vent gas and to discharge the vent gas to the outside.

3. The battery pack according to claim 1, wherein the discharge unit is provided on the lower side of the pack case and is configured to discharge the vent gas downward from the pack case.

4. The cell assembly is arranged along the width and length directions within the storage space of the pack case. The aforementioned discharge unit is A first discharge section is provided on the peripheral edge of the lower surface of the pack case, A second discharge section is provided along the width direction on the central region of the lower surface, The battery pack according to claim 1, comprising at least one of the following.

5. The aforementioned pack case is A pack frame is provided with its upper and lower ends open, and which houses the cell assembly inside. A lower frame portion is located at the bottom of the pack frame, on which the plurality of cell assemblies are placed and which supports the plurality of cell assemblies, The battery pack according to claim 1, including the following:

6. The aforementioned lower frame portion is A base plate that is coupled to the pack frame and supports the cell assembly, A bottom cover is positioned on the lower surface of the pack case so as to cover the base plate, The battery pack according to claim 5, including the following:

7. The cell assembly is arranged along the width and length directions within the storage space of the pack case. The aforementioned discharge unit is A first discharge section is provided on the peripheral edge of the lower surface of the pack case, A second discharge section is provided along the width direction on the central region of the lower surface, Including at least one of the following, The first discharge unit and the second discharge unit are, A discharge pipe is positioned to penetrate the base plate and the bottom cover, A vent valve is provided that is connected to the aforementioned discharge pipe and exposed on the outer surface of the bottom cover, The battery pack according to claim 6, including the following:

8. The battery pack according to claim 7, further comprising a first mesh net disposed in the discharge pipe for collecting solid discharged material discharged together with the vent gas.

9. The lower frame portion further includes a lower reinforcing bar provided between the bottom of the base plate and the bottom cover, The base plate and the bottom cover are provided with a plurality of through holes into which the discharge pipe is inserted. The battery pack according to claim 7, wherein the through hole is formed in a position that is not subject to interference from the lower reinforcing bar.

10. The cell assembly is arranged along the width and length directions within the storage space of the pack case. The battery pack according to claim 7, wherein the base plate is provided with a center beam that extends along the width direction of the cell assembly and separates adjacent cell assemblies in the longitudinal direction from each other.

11. The battery pack according to claim 10, wherein the center beam has discharge holes formed on both sides from which the vent gas is discharged.

12. The battery pack according to claim 11, wherein the discharge hole is formed on the upper side of the side surface of the center beam.

13. The second discharge unit is, A connecting pipe is provided in contact with the inner wall of the center beam, with one end positioned adjacent to the discharge hole and the other end connected to the discharge pipe, Multiple second mesh nets arranged in the connecting pipe, The battery pack according to claim 11, further comprising:

14. The battery pack according to claim 13, wherein a communication groove communicating with the discharge hole is formed on one side of the connecting pipe.

15. The aforementioned connecting pipe is The first connecting section has a connecting groove formed therein and a rectangular cross-section, The second connecting section has a circular cross-section, The first connecting section and the second connecting section are connected to each other, and the axial tube section is formed in a tapered shape with an inner diameter that gradually decreases along the axial direction, The battery pack according to claim 14, including the following:

16. The discharge pipe further includes a first mesh screen arranged therein to collect solid discharge material discharged together with the vent gas, The solid discharge is configured to be collected by the first mesh net and the second mesh net, The battery pack according to claim 13, wherein the vent valve is configured to discharge only the vent gas.

17. The cell assembly is housed in a module case to constitute a battery module. The aforementioned battery pack is Together with the center beam, a lateral partition wall divides the housing space for each battery module, A top cover that allows the aforementioned storage space to be sealed, It further includes, The battery pack according to claim 10, wherein vent gas from any of the battery modules is configured to be discharged from each of the housing spaces to the outside of the battery pack via the first or second discharge section without affecting other battery modules.

18. A hollow section is formed within the transverse diaphragm, and a hole is formed in the transverse diaphragm that communicates with the containment space. The battery pack according to claim 17, wherein the hollow portion of the transverse bulkhead and the hollow portion of the center beam are in communication.

19. The battery pack according to claim 10, wherein the second discharge section is inserted into the center beam.

20. An automobile comprising a battery pack according to any one of claims 1 to 19.

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