Battery pack case

Abstract

The disclosed battery pack case includes: a battery pack case; and a cover part covering the open upper surface of the battery pack case, in which fasteners for fixing the cover part to the battery pack case are each equipped with an exhaust mechanism for discharging pressure exceeding a preset value in the battery pack to the outside.

Description

Technical Field

[0001] The present disclosure relates to a battery pack case which can maintain a sealing structure of a cover portion restrained in a battery pack housing for a longer period of time in the event of thermal runaway.

[0002] This application claims priority to Korean Patent Application No. 10-2023-0114714 filed on August 30, 2023, and all contents disclosed in the specification and drawings of that application are incorporated into this application by reference. Background Art

[0003] Unlike primary batteries, secondary batteries are rechargeable and have been extensively researched and developed in recent years due to the potential for miniaturization and large capacity. Due to the increasing demand and technological development for mobile devices and electric vehicles and energy storage systems that have emerged in response to environmental protection needs, the demand for secondary batteries as energy sources is rapidly increasing.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, square batteries, and pouch-type batteries according to the shape of the battery case. In the secondary battery, an electrode assembly mounted in the battery case is a chargeable and dischargeable power generation device including a stacked structure of electrodes and separators.

[0005] Since secondary batteries are required to be used continuously over long periods of time, it is necessary to effectively control the heat generated during the charging and discharging process. If the secondary battery is not properly cooled, the increase in temperature will lead to an increase in current, which will lead to an increase in current, which will again lead to an increase in temperature, which will cause a chain reaction and ultimately lead to the catastrophic condition of thermal runaway.

[0006] In addition, if the secondary batteries are grouped in the form of modules or battery packs, thermal runaway caused by one secondary battery will cause other secondary batteries nearby to overheat continuously, resulting in a heat propagation phenomenon. In other words, when thermal runaway occurs in a battery module in a battery pack, a large amount of conductive dust, gas, and flames are emitted from the high-voltage terminals of the battery module, which causes dust to accumulate on the high-voltage terminals of other adjacent battery modules and triggers the heat propagation phenomenon through heat transfer via gas and flames.

[0007] When heat propagation occurs in a battery pack, the pressure and temperature inside the battery pack increase rapidly. In response to this rapid increase in pressure and temperature, the battery pack should maintain its structural robustness for a considerable period of time. If the battery pack has a structural collapse and outside air flows into the interior, the combustion reaction is quickly activated, resulting in significant risks outside the battery pack, such as fire, explosion, etc.

[0008] In the structure of the battery pack casing covering and restraining cover for the battery pack, there is a restriction on the volume increase inside the battery pack, and when an event such as heat propagation occurs, pressure release is not immediately performed and the battery pack structure may collapse before the exhaust device works, causing flames to be ejected to the outside.

[0009] The suppression and delay of heat propagation are critical, especially in electric vehicles, where they are directly related to life-threatening accidents, and regulations regarding this aspect are becoming increasingly stringent. In other words, in order to allow sufficient time for emergency evacuation and safety measures after thermal runaway occurs, there needs to be a sufficient time delay before the structural collapse of the battery pack occurs. Therefore, it is necessary to develop methods to ensure that the cover portion constrained in the battery pack housing can maintain a sealed structure for a sufficient period of time. Summary of the invention

[0010] Technical issues

[0011] An object of the present disclosure is to provide a battery pack housing, wherein, in a battery pack housing of a structure in which a cover portion is constrained relative to a battery pack outer shell, when an event of thermal runaway or heat propagation occurs and causes a rapid increase in internal pressure, the internal pressure can be properly released before the cover portion exceeds the limit of volume expansion, thereby preventing collapse of the battery pack housing and ensuring the working time of the exhaust device.

[0012] However, the technical problems to be solved by the present disclosure are not limited to the above-mentioned problems, and other problems not mentioned may be clearly understood by those skilled in the art from the description of the present disclosure described below.

[0013] Technical Solution

[0014] The present disclosure relates to a battery pack casing. In one example, the battery pack casing includes a battery pack outer shell and a cover portion covering an open top surface of the battery pack outer shell, wherein a fastener fixing the cover portion to the battery pack outer shell includes a venting mechanism for releasing pressure in the battery pack exceeding a predetermined value to the outside.

[0015] In one embodiment of the present disclosure, the fastener may secure the cover to the battery pack housing by screw engagement.

[0016] The fasteners may be engaged to a center beam and / or cross beams that traverse the interior of the battery pack housing.

[0017] The fastener may include a pressure inlet communicating with a space formed by an inner surface of the cover relative to the center beam and / or the cross beam, and a pressure outlet provided on a head protruding from an outer surface of the cover and communicating with the pressure inlet.

[0018] The cover may be fixed to a side frame of the battery pack case along an edge, wherein the fastener may restrain the cover from being detached from the battery pack case.

[0019] Furthermore, the battery pack housing is provided with at least one vent mechanism, wherein the vent mechanism embedded in the fastener can operate at a pressure lower than the operating pressure of the vent device.

[0020] In one embodiment, the exhaust mechanism may be a valve mechanism provided between the pressure inlet and the pressure outlet in the interior of the fastener and opened and closed by a spring.

[0021] Alternatively, the venting mechanism may be a burst disk disposed within the interior of the fastener between the pressure inlet and the pressure outlet.

[0022] Additionally, the venting mechanism may further include a mesh member disposed between the pressure inlet and the burst disk.

[0023] Additionally, the space formed between the burst disk and the mesh member may include a capsule sealed with a liquid fire extinguishing agent.

[0024] The capsules can be ruptured by the evaporation of the liquid extinguishing agent.

[0025] The capsule may rupture before the bursting disk.

[0026] For example, the liquid fire extinguishing agent may be a fluorinated ketone.

[0027] Beneficial Effects

[0028] According to the battery pack case of the present disclosure as described above, when the relatively thin cover expands and undergoes volume expansion as the internal pressure of the battery pack increases, the venting mechanism embedded in the fastener releases pressure before reaching the limit of volume expansion and the structure of the cover collapses. Therefore, in the event of thermal runaway or heat propagation, the structural collapse of the cover is delayed and suppressed.

[0029] In addition, since the exhaust mechanism embedded in the fastener is configured to work before the exhaust device provided in the battery pack housing, even if the exhaust device fails to work due to a sudden and rapid increase in internal pressure, the exhaust mechanism of the fastener works first, thereby preventing damage to the battery pack housing and ensuring sufficient time for the exhaust device to work normally.

[0030] However, technical effects that can be obtained by the present disclosure are not limited to the above-mentioned effects, and other effects that are not mentioned can be clearly understood by those skilled in the art from the description of the present disclosure described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Since the drawings attached to the present specification illustrate exemplary embodiments of the present disclosure and are used to help understand the technical concept of the present disclosure together with the detailed embodiments of the present disclosure described below, the present disclosure should not be restrictively interpreted based on the drawings.

[0032] Figure 1 is a diagram showing a battery pack case according to one embodiment of the present disclosure.

[0033] Figure 2 It is an exploded perspective view of the battery pack housing.

[0034] Figure 3 It is along Figure 1 Cross-sectional view along line “AA”.

[0035] Figure 4 yes Figure 3 Magnified view of part "B".

[0036] Figure 5 It is a diagram showing a fastener according to another embodiment.

[0037] Figure 6 and Figure 7 It is shown separately Figure 5 A diagram of a modified embodiment of the fastener is shown. DETAILED DESCRIPTION

[0038] The present disclosure may have various modifications and various embodiments, so specific embodiments thereof will be described in detail below.

[0039] However, it should be understood that the present disclosure is not limited to specific embodiments, and includes all modifications, equivalents, or substitutes within the spirit and technical scope of the present disclosure.

[0040] The terms "include", "comprising" and "having" used herein indicate the presence of the features, quantities, steps, actions, components or members described in this specification, or a combination thereof, and it should be understood that the possibility of the presence or addition of one or more other features, quantities, steps, actions, components, members or a combination thereof is not precluded.

[0041] In addition, in the present disclosure, when a portion of a layer, film, region, plate, etc. is disposed "on" another portion, this includes not only a case where one portion is "directly" disposed "on" another portion, but also a case where another portion is interposed therebetween. Conversely, when a portion of a layer, film, region, plate, etc. is disposed "below" another portion, this includes not only a case where one portion is directly disposed "below" another portion, but also a case where another portion is interposed therebetween. In addition, in the present application, "on" may include not only a case where it is disposed on an upper portion, but also a case where it is disposed on a lower portion.

[0042] The present disclosure relates to a battery pack casing. In one example, the battery pack casing includes a battery pack outer shell and a cover portion covering an open top surface of the battery pack outer shell, wherein a fastener fixing the cover portion to the battery pack outer shell includes a venting mechanism for releasing pressure in the battery pack exceeding a predetermined value to the outside.

[0043] Furthermore, the battery pack housing is provided with at least one vent device, wherein the vent mechanism embedded in the fastener can operate at a pressure lower than the operating pressure of the vent device.

[0044] According to the battery pack case of the present disclosure as described above, when the relatively thin cover expands and undergoes volume expansion as the internal pressure of the battery pack increases, the venting mechanism embedded in the fastener releases pressure before reaching the limit of volume expansion and the structure of the cover collapses. Therefore, in the event of heat propagation, the structural collapse of the cover is delayed and suppressed.

[0045] In addition, since the exhaust mechanism embedded in the fastener is configured to work before the exhaust device provided in the battery pack housing, even if the exhaust device fails to work due to a sudden and rapid increase in internal pressure, the exhaust mechanism of the fastener works first, thereby preventing damage to the battery pack housing and ensuring sufficient time for the exhaust device to work normally.

[0046] Specific instructions

[0047] Hereinafter, a specific embodiment of the battery pack case 10 according to the present disclosure will be described in detail with reference to the accompanying drawings. For reference, the front, rear, up, down, left, and right directions used to designate relative positions in the following description are for the purpose of understanding the present disclosure, and unless otherwise specified, refer to the directions shown in the drawings.

[0048] [First embodiment]

[0049] Figure 1 is a diagram showing a battery pack case according to one embodiment of the present disclosure, and Figure 2 This is an exploded perspective view of the battery pack housing. Figure 1 and Figure 2 , the battery pack case 10 of the present disclosure includes a battery pack housing 100 , a cover 200 and a fastener 300 .

[0050] The pack case 100 forms a space for accommodating at least one, preferably a plurality of battery modules (not shown). The pack case 100 includes a bottom plate 110 forming a bottom surface and a plurality of side frames 120 forming wall surfaces in all directions.

[0051] In addition, the battery pack housing 100 includes a central beam 130 and / or a cross beam 140 that form a plurality of spaces for accommodating a plurality of battery modules, respectively. The central beam 130 and the cross beam 140 are used to divide the accommodation space for the battery modules, and at the same time, enhance the overall rigidity of the battery pack housing 10. As will be described later, in the battery pack housing 10 of the present disclosure, the height of the central beam 130 and / or the cross beam 140 is formed to be lower than the height of the side frame 120.

[0052] The cover 200 refers to a member used as a lid covering the open top surface of the battery pack housing 100. The closure or sealing of the battery pack housing 100 is completed by the cover 200. The cover 200 has a low rigidity compared to the bottom plate 110, the side frame 120, the center beam 130 and the cross beam 140 that constitute the battery pack housing 100. Typically, the cover 200 is made of a relatively thin sheet. Due to the relatively low rigidity of the cover 200, the increase in the internal pressure of the battery pack housing 10 causes the cover 200 to deform during expansion, thereby having the effect of expanding the space inside the battery pack housing 10. Through this volume expansion, the initial rapid increase in pressure during a thermal runaway or heat propagation event is partially alleviated.

[0053] However, it is clear that there is a limit to the volume expansion of the cover 200 constrained to the battery pack housing 100, and therefore, the vent 150 provided in the battery pack housing 100 should work to release the excessively increased internal pressure before the constraint on the cover 200 is broken. However, in some cases, there may be a time delay before the vent 150 works, which may result in an explosion of the battery pack caused by the rupture of the cover 200 due to its inability to withstand the pressure.

[0054] The battery pack case 10 of the present disclosure ensures that the cover 200 remains well restrained by appropriately releasing pressure before the venting device 150 of the battery pack housing 100 works. To this end, the pressure release function is assigned to the fastener 300 that fixes the cover 200 relative to the battery pack housing 100. In other words, the fastener 300 that fixes the cover 200 relative to the battery pack housing 100 includes a venting mechanism 310 that releases pressure in the battery pack that exceeds a predetermined value to the outside.

[0055] Figure 3 It is along Figure 1 Cross-sectional view along line “AA”. Figure 4 yes Figure 3 In one embodiment of the present disclosure, the fastener 300 may fix the cover 200 to the battery pack housing 100 by screwing. In particular, the fastener 300 may be coupled to the center beam 130 and / or the cross beam 140 that crosses the interior of the battery pack housing 100.

[0056] refer to Figure 2 , the cover 200 is fixed to the side frame 120 of the battery pack housing 100 along its edge. The cover 200 is attached and fixed to the battery pack housing 100 by a plurality of bolts 400 that penetrate and engage the side frame 120 along the edge of the cover 200. On the other hand, the fastener 300 that fixes the cover 200 to the center beam 130 and / or the cross beam 140 has a tiny space formed between the inner surface of the cover 200 and the center beam 130 and / or the cross beam 140 to allow the pressure within the battery pack to act on the exhaust mechanism 310 embedded therein. In other words, the height of the center beam 130 and / or the cross beam 140 is lower than that of the side frame 120, and therefore, the inner surface of the cover 200 is not attached to the center beam 130 and / or the cross beam 140. In this regard, the fastener 300 does not tightly fix the cover 200 relative to the center beam 130 and / or the cross beam 140 , but may restrict the cover 200 from being separated from the battery pack case 10 .

[0057] refer to Figure 3 and Figure 4 , the fastener 300 includes a pressure inlet 330 and a pressure outlet 340, the pressure inlet 330 is communicated with a space formed by the inner surface of the cover 200 relative to the center beam 130 and / or the cross beam 140, and the pressure outlet 340 is provided on the head 302 protruding from the outer surface of the cover 200 and communicates with the pressure inlet 330 on the inner side. In addition, the exhaust mechanism 310 is provided between the pressure inlet 330 and the pressure outlet 340, and the exhaust mechanism 310 of the illustrated embodiment includes a valve mechanism 312 opened and closed by a spring 316. The valve mechanism 312 in the drawings includes a ball valve 314 and a spring 316, and when a pressure exceeding a set preload on the spring 316 is applied from the pressure inlet 330, the ball valve 314 moves to open the pressure outlet 340.

[0058] In addition, the battery pack housing 100 is provided with at least one exhaust device 150, wherein the exhaust mechanism 310 embedded in the fastener 300 can operate at a pressure lower than the working pressure of the exhaust device 150. In other words, when the pressure in the battery pack increases, the exhaust mechanism 310 embedded in the fastener 300 operates before the exhaust device 150. Therefore, the pressure in the battery pack is partially relieved and released by the volume expansion of the cover 200 and the operation of the exhaust mechanism 310, thereby suppressing the structural collapse of the battery pack housing 10 within a predetermined period of time, during which the exhaust device 150 starts to operate and the pressure in the battery pack is smoothly released.

[0059] [Second Embodiment]

[0060] Figure 5 2 is a diagram showing a fastener according to another embodiment. Figure 5In the embodiment of the present invention, the venting mechanism 310 includes a bursting disk 318 disposed within the interior of the fastener 300 between the pressure inlet 330 and the pressure outlet 340 .

[0061] The bursting disk 318 is a thin plate-shaped member of a metal material having a grooved portion formed on its surface by groove processing. When thermal runaway occurs in the battery pack case 10 and pressure increases, the pressure acts on the pressure inlet 330 of the fastener 300. The pressure transmitted from the pressure inlet 330 causes tensile strain on the bursting disk 318 having a fixed edge inside the fastener 300, thereby causing the grooved portion with low strength to tear, opening the pressure outlet 340.

[0062] Figure 6 and Figure 7 They are shown respectively Figure 5 FIG. 1 is a diagram of a modified embodiment of a fastener shown. Figure 6 In an embodiment of the present invention, the exhaust mechanism 310 may further include a mesh member 320 installed between the pressure inlet 330 and the burst disk 318. The mesh member 320 refers to a sheet-like structure having a plurality of small holes, and may perform a filtering function. In other words, by covering the pressure outlet 340 upstream of the exhaust mechanism 310 with the mesh member 320, high-temperature particles mixed in the exhaust gas are filtered by the mesh member 320 and are not released to the outside. In particular, since high-temperature particles exceeding a certain size serve as an ignition source for external fires, filtering by the mesh member 320 may effectively eliminate the cause of external fires. It should be noted that the mesh size of the mesh member 320 shown is exaggerated for the sake of clarity, and of course, the mesh member 320 may be formed with a mesh size smaller than this.

[0063] In addition, the mesh member 320 can be set as a porous member made of a thermally conductive material. In addition to the filtering function, this also has a fire extinguishing function. The porous mesh member 320 of the thermally conductive material absorbs the heat generated by the burning gas mixture and dissipates it to the surrounding environment, thereby reducing the combustion temperature so that the surrounding gas does not reach the autoignition temperature. This is because the high-temperature gas loses its heat to the thermally conductive porous structure when it passes through the mesh member 320. Therefore, when the flame generated by the thermal runaway generated in the battery pack housing 10 passes through the mesh member 320 upstream of the pressure outlet 340 of the exhaust mechanism 310, the flame loses the amount of heat that it can no longer maintain, thereby suppressing heat propagation or external fire.

[0064] In addition, as in Figure 7In the illustrated embodiment, the space formed between the burst disk 318 and the mesh member 320 may be provided with a capsule 322 sealed with a liquid fire extinguishing agent 324. When the sealed liquid fire extinguishing agent 324 absorbs heat from the high temperature gas and thereby evaporates, the capsule 322 may rupture from the inside, resulting in rapid volume expansion.

[0065] By providing a capsule 322 sealed with a liquid fire extinguishing agent 324 within the fastener 300, a fire caused by a thermal runaway event can be quickly responded to at the start of the fire. By using a liquid fire extinguishing agent 324, because it expands explosively in volume during the evaporation process, an effective fire extinguishing function can be expected while occupying a small space. In order to effectively extinguish the fire, it may be preferred that the capsule 322 ruptures before the burst disk 318. By appropriately selecting the material of the capsule 322, it can be designed to fully evaporate the liquid fire extinguishing agent 324 at a temperature lower than the pressure level at which the burst disk 318 ruptures. By rupturing the capsule 322 before the burst disk 318, the fire extinguishing effect can be more effective while maintaining the sealing of the interior of the battery pack housing 10.

[0066] exist Figure 7 In the embodiment of, the liquid fire extinguishing agent 324 can be a fluorinated ketone. Fluorinated ketone is a substance artificially made by replacing hydrogen atoms in ketones with fluorine, and is colorless and odorless, and its viscosity is almost the same as that of water, so it is easy to put into the capsule 322, and its insulation strength is twice or more that of nitrogen, because fluorine has stable properties, so it is non-conductive and does not cause reactions such as oxidation with substances in contact with it, and its surface tension is very small, so when it contacts an object, it expands well without forming droplets, so it is very suitable for fire extinguishing. In addition, fluorinated ketone is non-toxic and harmless to the human body, and is an effective fire extinguishing agent, which evaporates quickly when in contact with fire or smoke, quickly eliminates heat, and is more environmentally friendly than conventional fire extinguishing substances, because they do not leave any residue after evaporation. In particular, the non-conductivity due to the stability of fluorine is suitable for responding to fires caused by thermal runaway of secondary batteries.

[0067] However, since the boiling point of fluorinated ketones is 49°C, which is much lower than water, they exist as liquids at room temperature but evaporate quickly when the temperature rises. Therefore, it is necessary to design the material, thickness, etc. of the capsule 322 containing the liquid fluorinated ketone so that it acts as a suitable insulating material.

[0068] As described above, the present disclosure has been described in more detail through the drawings and embodiments. However, since the configuration described in the drawings or embodiments described herein is only one embodiment of the present disclosure and does not represent the overall technical spirit of the present disclosure, it should be understood that the present disclosure covers various equivalent forms, modified forms and replacement forms at the time of submitting this application.

[0069] [Description of Reference Signs]

[0070] 10: Battery pack housing 100: Battery pack housing

[0071] 110: Bottom plate 120: Side frame

[0072] 130: Center beam 140: Cross beam

[0073] 150: Exhaust device 200: Cover

[0074] 300: Fastener 302: Head

[0075] 310: Exhaust mechanism 312: Valve mechanism

[0076] 314: ball valve 316: spring

[0077] 318: Bursting disc 320: Mesh component

[0078] 322: Capsule 324: Liquid fire extinguishing agent

[0079] 330: Pressure inlet 340: Pressure outlet

[0080] 400: Bolt

Claims

1. A battery pack housing, comprising: Battery pack housing; as well as a cover portion covering an open top surface of the battery pack housing, The fastener for fixing the cover to the battery pack housing includes a venting mechanism for releasing pressure exceeding a predetermined value in the battery pack to the outside.

2. The battery pack housing according to claim 1, wherein: The fastener fixes the cover to the battery pack housing by screw engagement.

3. The battery pack housing according to claim 2, wherein: The fasteners are engaged to a center beam and / or cross beams that traverse the interior of the battery pack housing.

4. The battery pack housing according to claim 3, wherein: The fastener comprises: a pressure inlet communicating with a space formed by an inner surface of the cover relative to the central beam and / or the cross beam, and A pressure outlet is provided on a head portion protruding from an outer surface of the cover portion and is communicated with the pressure inlet.

5. The battery pack housing according to claim 4, wherein: The cover is fixed to the side frame of the battery pack housing along an edge, The fastener restricts the cover so that the cover does not separate from the battery pack housing.

6. The battery pack housing according to claim 1, wherein: The battery pack housing is provided with at least one exhaust device, Wherein, the exhaust mechanism embedded in the fastener operates at a pressure lower than the working pressure of the exhaust device.

7. The battery pack housing according to claim 6, wherein: The exhaust mechanism is a valve mechanism that is provided between the pressure inlet and the pressure outlet in the interior of the fastener and is opened and closed by a spring.

8. The battery pack housing according to claim 6, wherein: The venting mechanism is a bursting disk disposed within the interior of the fastener between the pressure inlet and the pressure outlet.

9. The battery pack casing according to claim 8, wherein: The vent mechanism also includes a mesh member disposed between the pressure inlet and the burst disk.

10. The battery pack housing according to claim 9, wherein: A space formed between the burst disk and the mesh member includes a capsule sealed with a liquid fire extinguishing agent.

11. The battery pack housing according to claim 10, wherein: The capsules are ruptured by vaporization of the liquid extinguishing agent.

12. The battery pack housing according to claim 11, wherein: The capsule ruptures before the bursting disk.

13. The battery pack housing according to claim 12, wherein: The liquid fire extinguishing agent is a fluorinated ketone.

Images