Battery packs and automobiles including them

Abstract

The battery pack according to the present invention includes a plurality of battery modules and a pack case having a housing space for housing the plurality of battery modules, wherein the pack case may be configured such that at least one surface of the pack case deforms when the internal pressure rises due to vent gas and flames generated by a thermal event in the battery modules.

Description

Technical Field

[0001] The present invention relates to a battery pack, and more specifically, when a thermal event occurs in a battery module, the internal space of the pack case expands in response to the increased internal pressure, reducing the internal pressure of the battery pack or reducing the rate of increase in internal pressure, thereby delaying heat transfer. This application claims priority based on Korean Patent Application No. 10-2023-0087250 filed on July 5, 2023, and all the contents disclosed in the specification and drawings of the said application are incorporated into this application.

Background Art

[0002] A secondary battery is a rechargeable semi-permanent battery that converts electrical energy into chemical energy, and is distinguished from a primary battery that cannot be reused after being used once.

[0003] In particular, lithium-ion secondary batteries have high energy storage density, can be lightweight and miniaturized, and have advantages such as excellent safety, low discharge rate, and long life. Recently, they have been actively used as batteries for electric vehicles. For reference, lithium-ion secondary batteries are generally classified into cylindrical, square, and pouch types according to their manufacturing form, and their uses are also diverse, including batteries for energy storage systems (ESS) and other electrical devices in addition to electric vehicle batteries.

[0004] Currently, the operating voltage per lithium-ion secondary battery cell is about 2.5V to 4.5V. Therefore, in order to apply a secondary battery as an energy source for an electric vehicle, a battery module is configured by connecting a plurality of lithium-ion secondary battery cells in series and / or in parallel, and further, a battery pack is configured by connecting the said battery modules in series and / or in parallel.

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

[0006] Therefore, if a specific battery module overheats or experiences a thermal runaway, the vent gas and flames generated in the affected battery module can increase the internal pressure within the battery pack, accelerating the accumulation of thermal energy and potentially easily triggering thermal propagation to adjacent battery modules. This can lead to a chain reaction of thermal runaway in battery modules and ultimately the explosion of the entire battery pack.

[0007] Therefore, it is necessary to improve the structure of the battery pack so that the internal pressure inside the battery pack, which rises due to vent gas and flames generated by the thermal event in the first battery module to ignite, can be reduced and thermal energy can be effectively dispersed, thereby delaying the thermal transition phenomenon that propagates in a chain reaction to adjacent battery modules. [Overview of the project] [Problems that the invention aims to solve]

[0008] The present invention has been made in consideration of the above problems, and the problem that the present invention aims to solve is to provide a battery pack that can delay the thermal transition phenomenon that propagates in a chain reaction to adjacent battery modules by mitigating the internal pressure inside the battery pack that has risen due to vent gas and flames generated by a thermal event in the first battery module to ignite, or by reducing the rate at which the internal pressure rises, and by effectively dispersing the thermal energy.

[0009] The technical problems that this invention aims to solve are not limited to those described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention below. [Means for solving the problem]

[0010] The battery pack according to the present invention includes a plurality of battery modules and a pack case having a housing space for housing the plurality of battery modules, wherein the pack case may be configured such that at least one surface of the pack case deforms when the internal pressure rises due to vent gas and flames generated by a thermal event in the battery modules.

[0011] In response to an increase in internal pressure, the pack case may form an expanded space separate from the storage space.

[0012] The aforementioned expanded space can be formed by deformation of the lower surface of the pack case.

[0013] The pack case may include a pack frame provided with an open upper and lower end for housing the battery module inside, and a lower frame portion positioned below the pack frame for mounting and supporting a plurality of the battery modules.

[0014] The lower frame portion may include a base plate connected to the pack frame and supporting the battery module, and a bottom cover positioned on the lower surface of the pack case so as to cover the base plate.

[0015] The bottom cover may be provided such that it plastically deforms and bulges downwards from the pack case when the internal pressure increases.

[0016] The bottom cover may be manufactured from steel or stainless steel.

[0017] The bottom cover may be provided with a thickness of 1.6 mm to 2.5 mm.

[0018] The base plate may be provided with a plurality of lower vent holes through which solid discharges, including the vent gas and electrode discharges, are moved into the expanded space.

[0019] The battery module is arranged along the width and length directions within the housing space of the pack case, and the plurality of lower vent holes may be arranged parallel to the width direction.

[0020] One or more of the lower vent holes may be provided for each of the battery modules.

[0021] The lower frame portion further includes a bottom reinforcement bar provided between the bottom of the base plate and the bottom cover, and the plurality of lower vent holes may be formed in positions that do not interfere with the bottom reinforcement bar.

[0022] A heat-resistant / fire-resistant gasket may be interposed between the base plate and the bottom cover.

[0023] The heat-resistant / fire-resistant gasket may be provided along the outer circumference of the base plate and the bottom cover.

[0024] The pack frame may be provided with a plurality of vent valves along the width direction of the battery module.

[0025] The vent valve can be activated when the internal pressure exceeds a preset pressure after the bottom cover has deformed and the expanded space has been formed.

[0026] The solid discharged material, along with the vent gas, is collected in the expanded space through the lower vent hole, and the vent valve may be configured to discharge only the vent gas.

[0027] In other embodiments, the expansion space is formed by the deformation of the upper and lower surfaces of the pack case, and the expansion space formed by the deformation of the upper surface of the pack case and the expansion space formed by the deformation of the lower surface of the pack case can be communicated with each other by the lower vent hole.

[0028] The pack case further includes a top cover disposed on the upper part of the pack frame so as to seal the accommodation space in which the battery module is accommodated. The bottom cover is provided so as to plastically deform and bulge downward of the pack case when the internal pressure rises, and the top cover can be provided so as to plastically deform and bulge upward of the pack case when the internal pressure rises.

[0029] Further, according to the present invention, an automobile including one or more of the above-described battery packs can be provided.

Advantages of the Invention

[0030] According to one aspect of the present invention, when a thermal event occurs in the first ignited battery module and internal pressure rises when vent gas, flame, etc. occur, an additional expansion space is formed to lower the internal pressure of the battery pack or reduce the internal pressure rise rate. Thereby, by effectively dispersing the thermal energy inside the battery pack, the heat transfer phenomenon that propagates chain-reaction to adjacent battery modules can be delayed, and an explosion of the entire battery pack can be prevented.

[0031] Also, according to one aspect of the present invention, solid discharges including electrode discharges are collected and separated in an additional expansion space formed on the lower side of the battery pack, and only vent gas can be discharged to the outside of the pack case, so that the clogging phenomenon of the vent valve can be minimized.

[0032] Furthermore, according to another aspect of the present invention, the top cover can also plastically deform in response to the rise in internal pressure of the battery pack to form an additional expansion space, thereby further reducing the internal pressure of the battery pack or further reducing the rate of internal pressure rise.

[0033] The effects of the present invention are not limited to those described above, and any effects not mentioned herein will be clearly understood by a person with ordinary skill in the art to which the present invention pertains from this specification and the accompanying drawings.

[0034] The following drawings accompanying this specification illustrate preferred embodiments of the invention and, together with the detailed description of the invention, serve to further illustrate the technical idea of ​​the invention; therefore, the invention should not be construed as being limited solely to what is shown in the drawings. [Brief explanation of the drawing]

[0035] [Figure 1] This is an overall perspective view of a battery pack according to one embodiment of the present invention. [Figure 2] Figure 1 is an exploded perspective view of the main components of the battery pack. [Figure 3] This is a schematic side cross-sectional view of a battery pack according to one embodiment of the present invention. [Figure 4] Figure 2 is an exploded perspective view of the lower frame of the battery pack. [Figure 5] This is a top view of a battery pack with the top cover removed, according to one embodiment of the present invention. [Figure 6] This is a bottom view of a battery pack with the bottom cover removed, according to one embodiment of the present invention. [Figure 7] This is an enlarged cross-sectional view of a battery pack according to one embodiment of the present invention. [Figure 8] This diagram schematically shows a deformed state of the bottom cover in a battery pack according to one embodiment of the present invention. [Figure 9]This diagram schematically shows the state in which vent gas is discharged through a vent valve in a battery pack according to one embodiment of the present invention. [Figure 10] This is a schematic side cross-sectional view of a battery pack according to another embodiment of the present invention. [Figure 11] This is a diagram illustrating an automobile relating to one embodiment of the present invention. [Modes for carrying out the invention]

[0036] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Prior to this, terms and words used in this specification and in the claims shall not be interpreted in their usual and dictionary sense, but rather in a sense and concept appropriate to the technical idea of ​​the present invention, in accordance with the principle that the inventor himself may appropriately define the concept of terms in order to best describe the invention.

[0037] Therefore, it should be understood that the configurations shown in the embodiments described herein represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the present invention, and that there are various equivalents and modifications that can be substituted therein at the time of filing this application.

[0038] Figure 1 is an overall perspective view of a battery pack according to one embodiment of the present invention, Figure 2 is an exploded perspective view of the main components of the battery pack in Figure 1, and Figure 3 is a schematic side cross-sectional view of the battery pack according to one embodiment of the present invention, which is a cross-sectional view taken along line A-A' in Figure 1.

[0039] Referring to Figures 1 to 3, the battery pack 10 according to this embodiment may include a plurality of battery modules 100 and a pack case 200 having a housing space S in which the plurality of battery modules 100 are housed.

[0040] Referring primarily to Figure 2, the battery module 100 may include a plurality of battery cells (not shown). The battery cell refers to a secondary battery including an electrode assembly, an electrolyte, and a pouch case housing the electrode assembly. In this embodiment, a pouch-type battery cell with high energy density and easy stacking is targeted, but it goes without saying that cylindrical or prismatic secondary batteries can also be applied as battery cells.

[0041] The pouch-type battery cell may include a pair of electrode leads (not shown) connected to the electrode assembly and extending outwards from the pouch case to function as electrode terminals. The pair of electrode leads may extend forward and backward along the longitudinal direction, or they may extend 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.

[0042] The battery module 100 may include a module case 120 for housing 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 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 are either positive or negative electrodes and are provided on both sides of the battery module 100, or in some cases on only one side.

[0043] As shown in Figure 2, the pack case 200 can accommodate a plurality of the battery modules 100. For this purpose, the pack case 200 may have a housing space S formed inside in which a plurality of the battery modules 100 are housed. The battery modules 100 may be arranged within the housing space S of the pack case 200 along the width direction (X-axis direction) and the length 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 the like, and may be made of a material with excellent mechanical rigidity (except for the lower surface of the pack case 200).

[0044] Referring mainly to Figure 2, the pack case 200 is shown separated into a pack frame 210 and a lower frame portion 220. As shown in the drawing, the pack case 200 is provided by the pack frame 210 and the lower frame portion 220 being interconnected, so that the bottom surface of the pack case 200 can become the top surface of the lower frame portion 220.

[0045] As shown in Figures 2 and 3, a plurality of lower vent holes H may be formed in the lower frame portion 220. The plurality of lower vent holes H may be provided at both ends in the longitudinal direction (Y-axis direction) of the battery module 100 and arranged parallel to the width direction (X-axis direction). One or more lower vent holes H may be provided per battery module 100.

[0046] Referring to Figure 3, the storage space S of the pack case 200 and the interior of the lower frame portion 220 can communicate with each other through the lower vent hole H. Gas discharges containing vent gas and solid discharges containing electrode discharges can be provided to move through the lower vent hole H.

[0047] Such a pack case 200 may be configured such that at least one surface of the pack case 200 deforms when the internal pressure rises due to vent gas and flames generated by a thermal event in the battery module 100. In response to the rise in internal pressure, an expanded space ES1 separate from the containment space S may be formed in the pack case 200. For example, as shown in Figure 3, the expanded space ES1 may be formed by the deformation of the lower surface of the pack case 200 (in this embodiment, the bottom cover 223, which will be described later).

[0048] More specifically, the lower frame portion 220 includes a base plate 221, a bottom reinforcement bar 222, and a bottom cover 223, as described later. When the internal pressure rises, the bottom cover 223 can deform within the pack case 200. This means that vent gas and solid discharges generated in the containment space S can be discharged into the lower frame portion 220 through the lower vent hole H. Here, the expanded space ES1 can be formed inside the lower frame portion 220 when the bottom cover 223 is deformed and expanded. As a result, when vent gas and flames are generated due to a thermal event, and the internal pressure of the battery pack 10 rises due to such discharges, another expanded space ES1 can be formed in addition to the containment space S of the battery pack 10. This allows the generated vent gas and solid discharges to be discharged not only into the containment space S but also into the expanded space ES1 formed by the deformation of the bottom cover 223 of the lower frame portion 220, thereby reducing the internal pressure of the battery pack 10 or slowing the rate of internal pressure increase. Since the thermal transition rate decreases when the increase in internal pressure is alleviated, the present invention makes it possible to improve the thermal transition delay performance.

[0049] The following provides a more detailed explanation of Pack Case 200.

[0050] Referring again to Figure 2, the pack case 200 may include a pack frame 210 that houses the battery module 100 inside, a top cover 240 positioned on the top of the pack frame 210, and a lower frame portion 220 positioned on the bottom of the pack frame 210.

[0051] The pack frame 210 may be provided as a rectangular frame. The pack frame 210 may also be provided with its upper and lower ends open. 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 accommodating the battery module 100.

[0052] Figure 4 is an exploded perspective view of the lower frame portion of the battery pack in Figure 2, Figure 5 is a top view of the battery pack with the top cover removed from the battery pack according to one embodiment of the present invention, Figure 6 is a bottom view of the battery pack with the bottom cover removed from the battery pack according to one embodiment of the present invention, and Figure 7 is an enlarged cross-sectional view of the battery pack according to one embodiment of the present invention.

[0053] Referring to Figures 2, 3, and 4 through 7, the pack frame 210 is provided with transverse partitions 211 (in the Y-axis direction) and longitudinal partitions 212 (in the X-axis direction) that partition the interior of the pack frame 210. The transverse partitions 211 are arranged in the length direction (Y-axis direction), but may be spaced apart by the width of the battery modules 100. The longitudinal partitions 212 are arranged to extend from the center of the pack frame 210 in the width direction (X-axis direction) and may be provided to separate the battery modules 100 that are adjacent to each other in the length direction. In this embodiment, it is shown that five transverse partitions 211 and one longitudinal partition 212 are provided inside the pack frame 210, and that 10 battery modules 100 are housed in the housing space S. On the other hand, the scope of the present invention is not limited to the number of transverse partitions 211 and longitudinal partitions 212 or the number of battery modules 100 housed in this embodiment.

[0054] Multiple vent valves 213 may be provided on one side of such a pack frame 210 along the width direction of the battery module 100. The vent valves 213 may be provided on both sides in the width direction (X-axis direction). Such vent valves 213 may be provided so that vent gas is discharged in the width direction (X-axis direction, or overall direction in the case of an automobile) of the battery module 100. The vent valves 213 can be operated to open and close the internal housing space S of the pack case 200 and the outside. The vent valves 213 operate when the internal pressure exceeds a preset pressure, which will be explained in detail later during the operation process.

[0055] Referring again to Figures 1 and 2, the top cover 240 is positioned on top of the pack frame 210 and may be 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.

[0056] Referring to Figures 4 to 7, the lower frame portion 220 is located below the pack frame 210 and is the portion that mounts and supports the multiple battery modules 100. The lower frame portion 220 may include a base plate 221 that is coupled to the pack frame 210 and supports the battery modules 100, a lower reinforcing bar 222 provided between the bottom of the base plate 221 and the bottom cover 223, and a bottom cover 223 that is positioned on the lower surface of the pack case 200 so as to cover the base plate 221.

[0057] The base plate 221 can be coupled to the lower part of the pack frame 210. Referring mainly to Figure 7, the base plate 221 can be coupled to a step 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 provided opposite the bottom of the plurality of battery modules 100 housed in the housing space S. This allows for stable mounting and support of the plurality of battery modules 100.

[0058] On the other hand, the bottom surface of the base plate 221 may be provided with channels through which multiple coolant flows are formed, although these channels are not shown in the figures, so that the base plate 221 and the cooling configuration are integrated. For example, the base plate 221 may be integrated with a heat sink.

[0059] Multiple lower vent holes H may be formed on the edge of the base plate 221. These multiple lower vent holes H may be arranged parallel to the width direction of the battery module 100. Pairs of the multiple lower vent holes H may be provided along both sides in the length direction (Y-axis direction) of the battery module 100. One or more of these lower vent holes H may be provided per battery module 100. In this embodiment, as shown in Figures 5 and 6, two lower vent holes H may be formed per battery module 100. Through these lower vent holes H, the vent gas and solid discharges, including electrode discharges, generated in the containment space S can move to the expanded space ES1 of the lower frame portion 220. On the other hand, the arrangement of the multiple lower vent holes H and the number of lower vent holes H per battery module 100 are not limited to this embodiment and can be changed in various ways.

[0060] Referring mainly to Figure 4, 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 provided so as to be in direct contact with the bottom of the base plate 221. The lower reinforcing bar 222 can support the base plate 221 from below and structurally reinforce it, thereby preventing sagging or bending of the base plate 221. Referring mainly to Figures 4 and 6, multiple such lower reinforcing bars 222 may be provided. Furthermore, the lower reinforcing bar 222 may be formed in a position that does not interfere with the multiple lower vent holes H. As a result, the lower reinforcing bar 222 does not obstruct the flow of vent gas and solid discharges discharged through the lower vent holes H.

[0061] As shown in Figure 4, a heat-resistant / fire-resistant gasket 224 may be interposed between the base plate 221 and the bottom cover 223. The heat-resistant / fire-resistant gasket 224 may be provided along the outer circumference of the base plate 221 and the bottom cover 223. Specifically, as shown in Figure 6, the heat-resistant / fire-resistant gasket 224 may be arranged along the edge area of ​​the base plate 221 and also provided at both ends of the lower reinforcing bar 222. As a result, as shown in Figure 7, the heat-resistant / fire-resistant gasket 224 can seal the base plate 221, the lower reinforcing bar 222, and the bottom cover 223 in that order from top to bottom in the outer circumference section where the lower reinforcing bar 222 is located, and can seal the base plate 221 and the bottom cover 223 in the outer circumference section where the lower reinforcing bar 222 is not located. The heat-resistant / fire-resistant gasket 224 may be made of a material that has heat resistance and fire resistance. The presence of such a heat-resistant / fire-resistant gasket 224 prevents vent gas or solid discharges from leaking out of the pack case 200 into the expanded space ES1, which is under relatively high temperature or high pressure conditions compared to the outside.

[0062] The bottom cover 223 may be positioned on the lower surface of the pack case 200 so as to cover the base plate 221. As shown in Figure 7, the bottom cover 223 may be positioned opposite the lower end of the pack frame 210 and spaced a predetermined distance from the base plate 221 and the lower reinforcing bar 222. Although not shown in the drawings, such a bottom cover 223 can be bolted to the pack frame 210. Even if the bottom cover 223 deforms due to increased internal pressure caused by vent gas and flames, the bottom cover 223 can be firmly fixed to the pack frame 210.

[0063] The bottom cover 223 may be provided such that it plastically deforms when the internal pressure in the containment space S increases, causing it to bulge downwards from the pack frame 210. In other words, the bottom cover 223 may be spaced at a predetermined distance or more from the base plate 221 or the lower reinforcing bar 222. Furthermore, the space formed by this separation can create an expanded space ES1. In this case, neither the base plate 221 nor the lower reinforcing bar 222 undergoes any deformation.

[0064] Such a bottom cover 223 can be manufactured from steel or stainless steel. Furthermore, the thickness t of the bottom cover 223 can be made relatively thin compared to the pack frame 210. In this embodiment, the bottom cover 223 can be made with a thickness of 1.6 mm to 2.5 mm. This allows the bottom cover 223 to be easily deformed, particularly plastically deformable, and the deformation can form an expanded space ES1 within the pack case 200. The expanded space ES1 can be formed by deforming the bottom cover 223 with little to no deformation of the base plate 221 and the lower reinforcing bar 222.

[0065] According to this embodiment, by providing an additional expansion space ES1 in addition to the existing containment space S, the internal volume of the pack case 200 that can contain vent gas and the like is increased, and the vent gas and solid discharges are arranged to be dispersed in the expansion space ES1, thereby reducing the internal pressure or the rate at which the internal pressure rises. This effectively disperses thermal energy, delaying the thermal transition phenomenon that is propagated in a chain reaction to adjacent battery modules 100, and preventing the explosion of the entire battery pack 10.

[0066] Furthermore, according to this embodiment, solid discharges, including electrode discharges, are collected and separated in the additional expansion space ES1 formed on the lower side of the battery pack 10, and only vent gas is discharged to the outside, thereby minimizing clogging of the vent valve 213. That is, the vent valve 213 can be activated when the internal pressure exceeds a preset pressure after the bottom cover 223 has deformed to form the expansion space ES1, and the vent valve 213 can be configured to discharge only the vent gas.

[0067] Furthermore, according to the above embodiment, it is possible to effectively prevent vent gases and flames from moving towards the upper side of the battery pack 10 in situations such as thermal runaway. In particular, when an occupant is located on the upper side of the battery pack 10, such as in an electric vehicle, according to the above embodiment, it is possible to suppress or delay the movement of gases and flames towards the occupant. In addition, while ensuring the safety of the upper side of the battery pack 10, it is possible to be freed from the structural and other constraints of the layout required to mount the battery pack 10 to the vehicle.

[0068] Figure 8 is a schematic diagram showing a deformed bottom cover in a battery pack according to one embodiment of the present invention, and Figure 9 is a schematic diagram showing a state in which vent gas is discharged through the vent valve in a battery pack according to one embodiment of the present invention.

[0069] 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 1 to 9.

[0070] First, when a thermal event occurs in a specific battery module 100 in Figure 8, the internal pressure in the containment space S increases, generating a large amount of vent gas and solid discharge within the containment space S.

[0071] Next, the vent gas and solid discharge can be discharged to the lower frame section 220 through the lower vent hole H. The vent gas and other materials enter the expanded space ES1 of the lower frame section 220, at which point the heat-resistant / fire-resistant gasket 224 can completely seal the base plate 221 and the bottom cover 223 (refer to the arrows in the drawing for the direction of movement of the vent gas and other materials).

[0072] Next, as the internal pressure in the containment space S increases, the bottom cover 223 undergoes plastic deformation in response to the internal pressure. In this process, the gap between the bottom cover 223 and the base plate 221 expands, and the inside of the lower frame portion 220 is formed as another expanded space ES1.

[0073] As a result, the generated vent gas and solid discharges can be discharged not only into the containment space S but also into the expansion space ES1. In particular, solid discharges that move into the expansion space ES1 can be collected in the expansion space ES1. Solid discharges, including electrode discharges, are solid particles and are relatively heavier than gaseous discharges, so they can be collected in the expansion space ES1.

[0074] Finally, after the expansion space ES1 is formed, if the internal pressure exceeds a preset pressure, the vent valve 213 operates as shown in Figure 9. Through the vent valve 213, only the vent gas in the containment space S and the expansion space ES1 is discharged to the outside of the pack case 200. The direction of discharge of the vent gas can be in the width direction of the battery module 100. In addition, solid discharges, including electrode discharges, remain collected within the expansion space ES1 due to their own weight.

[0075] This stepped configuration allows for a reduction in the internal pressure of the battery pack 10 or a decrease in the rate of internal pressure increase. This effectively disperses thermal energy, thereby delaying the thermal transition phenomenon that propagates sequentially to adjacent battery modules 100.

[0076] Furthermore, solid discharges, including electrode discharges, are collected and separated in the additional expansion space ES1 formed on the lower side of the battery pack 10, and only vent gas is discharged to the outside, thereby minimizing clogging of the vent valve 213.

[0077] Next, other embodiments of the battery pack 10 of the present invention will be briefly described with reference to Figure 10.

[0078] Figure 10 is a schematic side cross-sectional view of a battery pack according to another embodiment of the present invention.

[0079] The same part numbers as in the previous drawing refer to the same part, and redundant explanations of the same part will be omitted. The main focus will be on explaining the differences from the embodiment described above.

[0080] The pack case 200 is provided with a top cover 240 on its upper part, and although not shown in the drawing, the top cover 240 is bolted to the upper surface of the pack frame 210. At this time, connecting members are arranged along the edge of the top cover 240 so that it can be connected to the pack frame 210. However, there is no connection between the central region of the top cover 240 and the vertical bulkhead 212 of the pack frame 210.

[0081] In such a pack case 200, an expanded space separate from the storage space S is formed in response to the increase in internal pressure, and an expanded space ES2 may be formed by the deformation of the upper surface of the pack case 200, along with the expanded space ES1 formed by the deformation of the lower surface of the pack case 200 in the above embodiment.

[0082] Specifically, the top cover 240 may be provided such that it plastically deforms and bulges upward above the pack case 200 when the internal pressure rises. This allows for the formation of an expanded space ES2 formed by the deformation of the top cover 240 of the pack case 200. In this way, the expanded space ES2 formed on the upper side of the pack case 200 communicates with the storage space S of the pack case 200 and can communicate with the expanded space ES1 formed by the deformation of the lower surface of the pack case 200 by the lower vent hole H.

[0083] In this embodiment, the top cover 240 may be manufactured from aluminum or stainless steel so as to be easily plastically deformable. The top cover 240 may be provided with a thickness of 1.6 mm to 2.5 mm, similar to the bottom cover 223.

[0084] With this configuration, when a thermal event occurs, the vent gas and solid discharge are released and move upward to the containment space S (see the thick arrow pointing in the Z-axis direction in the drawing), temporarily expanding the top cover 240 to form the expanded space ES2. The vent gas and solid discharge are also moved to both sides in the drawing (see the thick arrows pointing in the ±Y-axis direction and the thick arrow pointing in the -Z-axis direction in the drawing), secondarily expanding the bottom cover 223 through the lower vent hole H to form the expanded space ES1. The deformation of the top cover 240 to form the expanded space ES2 on the upper side of the pack case 200 has the advantage of making the movement of the generated vent gas and other materials smoother. Furthermore, compared to the above embodiment, the increased size of the expanded space ES2 has the advantage of increasing the available space for containing the vent gas and other materials.

[0085] On the other hand, the order in which the expanded spaces ES1 and ES2 are formed is not limited to the above description. For example, the bottom cover 223 may deform to form the expanded space ES1 first at the bottom of the pack case 200, followed by the top cover 240 deforming to form the expanded space ES2 at the top of the pack case 200. Alternatively, expanded spaces ES1 and ES2 may be formed simultaneously at the top and bottom of the pack case 200.

[0086] According to this embodiment, expanded spaces ES1 and ES2 are formed on the upper and lower surfaces of the pack case 200, respectively. This further reduces the internal pressure that has risen due to a thermal event, or further reduces the rate at which the internal pressure rises. By effectively dispersing thermal energy, the thermal transition phenomenon that propagates sequentially to adjacent battery modules 100 can be delayed. In particular, the top cover 240 also undergoes plastic deformation in response to the rise in internal pressure of the battery pack 10, and an additional expanded space ES2 can be formed in the expanded space ES1 created by the deformation of the housing space S and the bottom cover 223. This further reduces the internal pressure of the battery pack 10 or further reduces the rate at which the internal pressure rises.

[0087] Furthermore, solid discharges, including electrode discharges, are collected and separated in the additional expansion space ES1 formed on the lower side of the battery pack 10, and only vent gas is discharged to the outside, thereby minimizing clogging of the vent valve 213 (see Figure 9).

[0088] 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 BMS (Battery Management System), a current sensor, a fuse, etc., although these are not shown in the figures.

[0089] Figure 11 is a diagram illustrating an automobile according to one embodiment of the present invention.

[0090] Referring to Figure 11, the battery pack 10 according to the present invention can be applied to an automobile V such as an electric vehicle or a hybrid vehicle. That is, an 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 body frame under the vehicle seats or in the trunk space, and when installing it in the vehicle, the battery pack 10 can be installed in the reverse order of placement as needed.

[0091] In this specification, terms indicating directions such as up, down, left, right, front, and back are used, but such terms are for explanatory convenience 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.

[0092] Although the present invention has been described above with reference to limited embodiments and drawings, it goes without saying that the present invention is not limited thereto, and various modifications and variations are possible within the equivalent scope of the technical idea of ​​the present invention and the claims described below by persons with ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0093] V: Automobile 10: Battery Pack 100: Battery Module 120: Module Case 140: Terminal 200: Pack Case S: Containment space 210: Pack Frame 211: Transverse bulkhead 212: Mediastinal wall 213: Vent Valve 220: Lower frame section ES1, ES2: Extended Spaces 221: Base plate H: Lower vent hole 222: Lower reinforcement bar 223: Bottom cover 224: Heat-resistant / fire-resistant gasket 240: Top cover

Claims

1. Multiple battery modules, A pack case having a housing space formed for housing multiple battery modules, The battery pack is configured such that at least one surface of the pack case deforms when the internal pressure increases due to vent gas and flames generated by a thermal event in the battery module.

2. The battery pack according to claim 1, wherein the pack case has an expanded space separate from the housing space formed in response to an increase in the internal pressure.

3. The battery pack according to claim 2, wherein the expanded space is formed by deformation of the lower surface of the pack case.

4. The aforementioned pack case is A pack frame is provided with its upper and lower ends open, and which houses the battery module inside. The battery pack according to claim 2, further comprising a lower frame portion disposed below the pack frame for mounting and supporting a plurality of the battery modules.

5. The aforementioned lower frame portion is A base plate connected to the pack frame and supporting the battery module, The battery pack according to claim 4, further comprising: a bottom cover disposed on the lower surface of the pack case so as to cover the base plate.

6. The battery pack according to claim 5, wherein the bottom cover is provided such that it plastically deforms and bulges downward when the internal pressure increases.

7. The battery pack according to claim 5, wherein the bottom cover is made of steel or SUS material.

8. The battery pack according to claim 5, wherein the bottom cover is provided to be 1.6 mm to 2.5 mm thick.

9. The battery pack according to claim 5, wherein the base plate is provided with a plurality of lower vent holes for moving the vent gas and solid discharges including electrode discharges into the expanded space.

10. The battery modules are arranged along the width and length directions within the housing space of the pack case. The battery pack according to claim 9, wherein the plurality of lower vent holes are arranged parallel to the width direction.

11. The battery pack according to claim 10, wherein one or more of the lower vent holes are provided for each of the battery modules.

12. The lower frame portion further includes a lower reinforcing bar provided between the bottom of the base plate and the bottom cover, The battery pack according to claim 10, wherein the plurality of lower vent holes are formed in positions that do not interfere with the lower reinforcing bar.

13. The battery pack according to claim 5, wherein a heat-resistant / fire-resistant gasket is interposed between the base plate and the bottom cover.

14. The battery pack according to claim 13, wherein the heat-resistant / fire-resistant gasket is provided along the outer circumference of the base plate and the bottom cover.

15. The battery pack according to claim 9, wherein the pack frame is provided with a plurality of vent valves along the width direction of the battery module.

16. The battery pack according to claim 15, wherein the vent valve operates when the internal pressure exceeds a preset pressure after the bottom cover has deformed to form the expanded space.

17. The solid discharged material, along with the vent gas, is collected in the expanded space through the lower vent hole. The battery pack according to claim 16, wherein the vent valve is provided to discharge only the vent gas.

18. The aforementioned expanded space is formed by the deformation of the upper and lower surfaces of the pack case. The battery pack according to claim 9, wherein an expanded space formed by deformation of the upper surface of the pack case and an expanded space formed by deformation of the lower surface of the pack case are in communication with each other through the lower vent hole.

19. The pack case further includes a top cover positioned on top of the pack frame to seal the housing space in which the battery module is housed, The bottom cover is provided such that it plastically deforms and bulges downward when the internal pressure rises, The battery pack according to claim 18, wherein the top cover is provided such that it plastically deforms and bulges upward above the pack case when the internal pressure rises.

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

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