Pack case with improved heat transfer prevention structure

Abstract

In one example, the disclosed pack case includes a base plate forming a bottom surface, side beams connected along the front, rear, left and right edges of the base plate to form a storage space, an upper cover connected to the side beams so as to cover the upper surface of the storage space, and a lid bracket connected to the upper cover and the side beams.

Description

[Technical field]

[0001] The present invention relates to a pack case that houses a plurality of battery modules, and to a pack case having reinforced structural rigidity so that it can withstand for a long period of time even if the internal pressure of the pack case increases due to a thermal runaway phenomenon occurring in a battery cell in a battery module.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0124853 dated September 30, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference. [Background technology]

[0003] Unlike primary batteries, secondary batteries are rechargeable and have the potential to be small and have large capacity, and have been the subject of much research and development in recent years. The demand for secondary batteries as an energy source is rapidly increasing due to the increasing technological development and demand for mobile devices, as well as the emergence of electric vehicles and energy storage systems in response to the modern demand for environmental protection.

[0004] Secondary batteries are classified into coin type batteries, cylindrical type batteries, square type batteries, and pouch type batteries according to the shape of the battery case. The electrode assembly installed inside the battery case of the secondary battery is a power generating element capable of charging and discharging, which is made of a laminated structure of electrodes and a separator.

[0005] Since secondary batteries are required to be used continuously for long periods of time, it is necessary to effectively control the heat generated during the charging and discharging process.If secondary batteries are not cooled smoothly, a positive feedback chain reaction occurs in which an increase in temperature causes an increase in current, and the increase in current causes another increase in temperature, resulting in a catastrophic state of thermal runaway.

[0006] In addition, when secondary batteries are grouped together in the form of a module or pack, thermal runaway in one secondary battery can cause a thermal propagation phenomenon in which other surrounding secondary batteries are continuously overheated. That is, when thermal runaway occurs in a battery module in a battery pack, a large amount of conductive dust, gas, and flames are ejected from the high-voltage terminal of the battery module, causing dust to accumulate at the high-voltage terminal of other adjacent battery modules, and the thermal propagation phenomenon is triggered by the heat transfer caused by the gas and flame.

[0007] The internal pressure of the battery pack increases due to the heat propagation generated inside the battery pack. The pack case that houses multiple battery modules can withstand a certain amount of internal pressure and resist structural deformation, but as thermal runaway and heat propagation progress, the internal pressure increases to a level that the pack case cannot withstand.

[0008] If the internal pressure rises above the limit of the pack case's structural rigidity, the pack case joints will widen, causing high-temperature, high-pressure dust, gas, and flames to erupt from the widened gaps, which can cause a fire around the battery pack. Therefore, the higher the structural rigidity of the pack case, the more advantageous it is in delaying the spread of heat to the outside of the battery pack.

[0009] In order to ensure excellent structural rigidity of such a pack case, the pack case can be constructed from a thicker and stronger material, or the pack case can be manufactured in a form that can minimize seams, for example, by cutting a metal block. However, such a method drastically increases the production cost of the pack case, and the excessive increase in weight limits its application in fields where weight is important, such as automotive batteries. Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a pack case that can significantly enhance the structural rigidity without significantly increasing the weight of the pack case.

[0011] However, the technical problem that the present invention aims to solve is not limited to the above-mentioned problem, and other problems not mentioned can be clearly understood by a person skilled in the art from the description of the invention described below. [Means for solving the problem]

[0012] The present invention relates to a pack case, which in one example includes a base plate forming a bottom surface, side beams connected along the front, rear, left and right edges of the base plate to form a storage space, an upper cover connected to the side beams so as to cover the top surface of the storage space, and a lid bracket connected to the upper cover and the side beams.

[0013] In one embodiment of the present invention, the lid bracket has a bent shape that contacts both the edge of the upper cover and the upper corner of the side beam.

[0014] And, one lid bracket may be provided for each of the side beams.

[0015] The lid bracket may then be coupled to the top cover and the side beam by separable fasteners or by welding.

[0016] Also, the lid bracket can be fixed together with the upper cover to the side beam by a fastening member.

[0017] A gasket may be interposed between the side beam and the upper cover.

[0018] Meanwhile, according to another embodiment of the present invention, the side beams further include corner brackets coupled to each other along a height direction of the corners where the side beams are adjacent to each other.

[0019] The corner bracket may have a bent shape that contacts both adjacent side beams.

[0020] The corner brackets may then be attached to the side beams by separable fasteners or by welding.

[0021] Heat-resistant silicon may be interposed between the contact surfaces of the side beams.

[0022] A brazing material may be interposed between the contact surfaces of the corner bracket and the side beam. Effect of the Invention

[0023] In the pack case of the present invention having the above-mentioned configuration, even if thermal runaway occurs in the battery module installed in the storage space and a large amount of conductive dust, gas, and flames are ejected, causing the internal pressure to rise excessively, the fixing force of the upper cover and / or side beam is strengthened by the lid bracket and / or corner bracket, thereby more effectively suppressing leakage of dust, gas, etc.

[0024] In particular, the present invention has the advantage that the pressure resistance of the pack case can be improved by simply adding a bent lid bracket and / or a corner bracket, without forming the pack case out of a thicker and stronger material, and therefore there is no excessive burden on manufacturing costs, process efficiency, or weight increase of the battery pack.

[0025] However, the technical effects that can be obtained by the present invention are not limited to the effects described above, and other effects not mentioned can be clearly understood by those of ordinary skill in the art from the description of the invention described below.

[0026] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical ideas of the present invention. Therefore, the present invention should not be interpreted as being limited to the matters depicted in such drawings. [Brief description of the drawings]

[0027] [Figure 1] 1 is a diagram showing an embodiment of a pack case according to the present invention. [Diagram 2] 1 is a diagram showing an embodiment of mounting a lid bracket. [Diagram 3] FIG. 4 is a cross-sectional view showing a mounting structure of a lid bracket. [Figure 4] 1 is a view showing an embodiment of mounting a corner bracket. [Diagram 5] 1 is a view showing a state in which a corner bracket is mounted between side beams. [Figure 6] FIG. 13 is a cross-sectional view showing an embodiment in which heat-resistant silicon is interposed between side beams. [Figure 7] 11 is a cross-sectional view showing an embodiment in which a brazing material is interposed between a corner bracket and a side beam. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described in detail below.

[0029] However, this is not intended to limit the invention to any particular embodiment, but it should be understood to include all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0030] In the present invention, terms such as "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and may be understood as not precluding the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0031] In addition, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion in between. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion in between. In addition, in the present application, being "on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0032] The present invention relates to a pack case, which in one example includes a base plate forming a bottom surface, side beams coupled along the front, rear, left and right edges of the base plate to form a storage space, an upper cover coupled to the side beams so as to cover an upper surface of the storage space, and a lid bracket coupled to the upper cover and the side beams.

[0033] In one embodiment of the present invention, the lid bracket has a bent shape that contacts both the edge of the upper cover and the upper corner of the side beam.

[0034] In the pack case of the present invention having such a configuration, even if thermal runaway occurs in the battery module mounted in the storage space and a large amount of conductive dust, gas, and flames are ejected, causing the internal pressure to rise excessively, the fixing force of the upper cover is strengthened by the lid bracket, thereby more effectively preventing leakage of dust and the like.

[0035] In particular, the present invention has the advantage that the pressure resistance of the pack case can be improved by simply adding a bent lid bracket without constructing the pack case from a thicker and stronger material, and therefore there is no excessive burden on manufacturing costs, process efficiency, or increase in the weight of the battery pack.

[0036] Hereinafter, specific embodiments of the pack case according to the present invention will be described in detail with reference to the accompanying drawings. For reference, the directions of front, back, up, down, left and right specifying relative positions used in the following description are intended to facilitate understanding of the invention, and unless otherwise specified, are based on the directions shown in the drawings.

[0037] (First embodiment) FIG. 1 is a diagram showing an embodiment of a pack case 100 according to the present invention. The pack case 100 refers to a case of a battery pack 10 mounting a plurality of battery modules 200. The pack case 100 has a frame structure that can protect the mounted battery modules 200 while forming a space for accommodating a plurality of battery modules 200 and ensure the structural rigidity of the battery pack 10. The battery pack 10 exemplarily shown in FIG. 1 mounts a total of eight battery modules 200, which are arranged such that the front faces the center beam 130 side crossing the center of the pack case 100. A high-voltage terminal for connecting a bus bar is disposed on the front of the battery module 200, and a thermal barrier 210 for protecting the high-voltage terminal is attached to the battery module 200.

[0038] The pack case 100 includes a base plate 110 forming a bottom surface, and side beams 120 that are coupled along the front, rear, left and right edges of the base plate 110 to form an accommodation space. Four side beams 120 are provided to form the pack case 100 in a hexahedral shape. Here, two of the side beams 120 forming the side walls of the pack case 100 may be referred to as a front beam and a rear beam, respectively, depending on the position designation of the front and rear surfaces defined for the battery pack 10.

[0039] The pack case 100 includes an upper cover 140 coupled to the side beams 120 to cover an upper surface of an accommodation space in which the battery modules 200 are mounted. A gasket 150 may be interposed between the side cover and the upper cover 140 to seal a contact surface between the side cover and the upper cover 140.

[0040] A conventional pack case uses a fastening member 500, such as a bolt shown in Fig. 1, that can separate the top cover 140 from the side beam 120. The bolt passes through a fastening hole 142 formed in the top cover 140 and is fastened to a screw hole 122 formed in the upper surface of the side beam 120.

[0041] According to this conventional configuration, when the battery module 200 operates normally, the fastening force of the fastening member 500 provides sufficient adhesion to the gasket 150, faithfully maintaining the airtightness of the battery pack. However, when the internal pressure of the pack case 100 increases due to thermal runaway occurring in the battery module 200, the fastening force of the fastening member 500 weakens due to the pressure, and gaps are generated between the gaskets 150, causing dust, gas, and flames to spew out to the outside. In addition, there is a problem in that oxygen is supplied to the gaps generated in the upper cover 140, causing the flames inside the pack case 100 to grow more violently.

[0042] The pack case 100 of the present invention includes a lid bracket 300 for reinforcing the fixing force of the upper cover 140. The lid bracket 300 is connected to the upper cover 140 and the side beam 120, and in the illustrated embodiment, the lid bracket 300 has a bent shape that contacts both the edge of the upper cover 140 and the upper corner of the side beam 120. The lid bracket 300 of this bent shape provides additional fixing force to the upper cover 140 by connecting one bent surface to the upper cover 140 and the other bent surface to the side beam 120 along the edge of the pack case 100 where the upper cover 140 and the side beam 120 are in contact with each other.

[0043] Due to the additional fixing force of the lid bracket 300, even if the internal pressure of the pack case 100 rises excessively, the adhesion between the upper cover 140 and the gasket 150 is maintained well, so that leakage of dust, gas, etc. is more effectively suppressed or delayed.

[0044] In addition, since the weight and volume of the lid bracket 300 itself is not so large, the pressure resistance of the pack case 100 can be improved by simply adding the bent lid bracket 300 without constructing the pack case 100 out of a thicker and stronger material, so there is no excessive burden in terms of manufacturing costs, process efficiency, or increase in the weight of the battery pack 10.

[0045] Fig. 2 is a view showing an embodiment of mounting the lid bracket 300. Referring to Fig. 2, one lid bracket 300 is provided for each side beam 120. Since the lid bracket 300 has a bent shape, it is advantageous to allocate one lid bracket 300 to each side beam 120, rather than manufacturing a single side beam 120 connected across multiple side beams 120.

[0046] FIG. 3 is a cross-sectional view showing the mounting structure of the lid bracket 300. As described above, the lid bracket 300 may be connected to the upper cover 140 and the side beam 120 using a separable fastening member 500, for example, a bolt as shown in the drawing. In addition to the fastening member 500, the lid bracket 300 may be mounted by welding. However, when a separable fastening member 500 is used, it is advantageous in that it is easy to remove the lid bracket 300 and the upper cover 140 to perform maintenance inside the battery pack 10, and it is also advantageous in that the lid bracket 300 can be fixed to the side beam 120 together with the upper cover 140 by the fastening member 500 as shown in FIG. 3, which improves workability.

[0047] Second embodiment The second embodiment of the present invention is an embodiment that can further strengthen the pressure resistance of the pack case 100, and further includes corner brackets 400 that reinforce the fastening structure between the side beams 120.

[0048] 4 shows an embodiment of a corner bracket 400, which is attached along the height direction of the corner where the side beams 120 meet. Since the contact surface between the side beams 120 is not large, a separate gasket is not generally installed, but if the internal pressure increases due to thermal runaway, the side beams 120 will lift up, causing dust and gas to escape.

[0049] In order to prevent such leakage between the side beams 120, a corner bracket 400 is installed. The corner bracket 400 has a bent shape that contacts both of the side beams 120 adjacent to each other on both sides, and strengthens the fixing force between the side beams 120 by connecting them along the height direction of the corners where the side beams 120 are adjacent to each other.

[0050] FIG. 5 shows the state in which corner brackets 400 are installed between side beams 120. As the fixing force between the side beams 120 is improved, the space between the side beams 120 does not easily widen even when strong internal pressure is applied, thereby suppressing the escape of dust, gas, etc. from between the side beams 120.

[0051] 4 and 5 show the corner bracket 400 being connected to the side beam 120 by a separable fastener 500, it is also possible to join the corner bracket 400 to the side beam 120 via welding, as described in the first embodiment.

[0052] 6 is a cross-sectional view showing an embodiment in which heat-resistant silicone 600 is interposed between side beams 120. The corner brackets 400 are used to improve the fixation of the corners in the height direction of the pack case 100, and heat-resistant silicone 600 can be interposed between the contact surfaces of the side beams 120. The heat-resistant silicone 600 maintains good adhesion between the side beams 120 even in a high-temperature environment, thereby further preventing the ejection of the battery module 200 from leaking.

[0053] In order to improve the adhesion between the corner bracket 400 and the side beam 120, a brazing material 610 may be interposed on the contact surface between the corner bracket 400 and the side beam 120. That is, a brazing process may be performed on the contact surface between the corner bracket 400 and the side beam 120. After a thin brazing material is sandwiched between the inner surface of the corner bracket 400 and fastened to the side beam 120, the brazing material 610 may be interposed on the contact surface between the corner bracket 400 and the side beam 120 by applying heat to an appropriate temperature. The brazing material 610 melts to fill the gap and then solidifies, which not only further strengthens the fixing force of the corner bracket 400 but also improves airtightness.

[0054] The present invention has been described in detail above with reference to the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments, etc. in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0055] 10: Battery pack 100: Pack case 110: Base plate 120: Side beam 122: Screw hole 130: Center beam 140: Top cover 142: Concluding hole 150: Gasket 200: Battery module 210: Thermal Barrier 300: Lid bracket 400: Corner bracket 500: Fastening members 600: Heat-resistant silicone 610: Brazing material

Claims

1. A base plate forming a bottom surface; side beams coupled to the base plate along the front, rear, left and right edges thereof to form an accommodation space; an upper cover coupled to the side beam so as to cover an upper surface of the receiving space; a lid bracket coupled to the top cover and to a side beam.

2. The lid bracket is The pack case according to claim 1 , wherein the pack case has a bent shape that contacts both edges of the upper cover and upper corners of the side beams.

3. The lid bracket is The pack case of claim 2 , wherein one is provided for each of the side beams.

4. The lid bracket is The pack case according to claim 2 , wherein the top cover and the side beams are connected to each other by separable fastening members or by welding.

5. The lid bracket is The pack case according to claim 4 , wherein the pack case is fixed together with the upper cover to the side beams by fastening members.

6. The pack case according to any one of claims 1 to 5, wherein a gasket is interposed between the side beam and the upper cover at a contact surface thereof.

7. The pack case according to any one of claims 1 to 5, further comprising a corner bracket that connects the side beams along a height direction of the corners where the side beams are adjacent to each other.

8. The corner bracket is 8. The pack case according to claim 7, wherein the pack case has a bent shape in which the adjacent side beams contact each other.

9. The corner bracket is The pack case according to claim 8 , which is connected to the side beams by separable fasteners or by welding.

10. The pack case according to claim 8 , wherein heat-resistant silicone is interposed between the contact surfaces of the side beams.

11. The pack case according to claim 7 , wherein a brazing material is interposed between the corner bracket and the side beam at a contact surface thereof.

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