Pack case with improved thermal propagation preventing structure

Abstract

The disclosed invention relates to a pack case, and in one example, comprises a base plate forming a bottom surface, side beams each coupled along the front, rear, left, and right corners of the base plate to form a receiving space, an upper cover coupled to the side beams to cover the upper surface of the receiving space, and a lead bracket coupled to the upper cover and the side beams.

Description

Technology Field

[0001] The present invention relates to a pack case accommodating a plurality of battery modules, and more specifically, to a pack case with reinforced structural rigidity capable of withstanding an increase in internal pressure of the pack case due to a thermal runaway phenomenon occurring in a battery cell within a battery module for an extended period. Background Technology

[0002] Unlike primary batteries, secondary batteries are rechargeable and are currently the subject of extensive research and development due to their potential for miniaturization and high capacity. The demand for secondary batteries as an energy source is increasing rapidly due to the growing technological development and demand for mobile devices, as well as the rise of electric vehicles and energy storage systems driven by the contemporary need for environmental protection.

[0003] Rechargeable batteries are classified into coin batteries, cylindrical batteries, prismatic batteries, and pouch batteries according to the shape of the battery case. In rechargeable batteries, the electrode assembly mounted inside the battery case is a power generation device capable of charging and discharging, consisting of a laminated structure of electrodes and separators.

[0004] Since secondary batteries require continuous use over long periods, it is necessary to effectively control the heat generated during the charging and discharging process. If the cooling of the secondary battery is not performed smoothly, a positive feedback chain reaction occurs where the temperature rise causes an increase in current, and this increase in current again causes a temperature rise, eventually leading to a catastrophic state of thermal runaway.

[0005] In addition, when secondary batteries are grouped in the form of modules or packs, a thermal propagation phenomenon occurs in which surrounding secondary batteries are continuously overheated due to thermal runaway in one secondary battery. That is, when thermal runaway occurs in a battery module within a battery pack, a large amount of conductive dust, gas, and flames are ejected from the high-voltage terminal of the battery module, and consequently, dust accumulates on the high-voltage terminal of an adjacent battery module, and the thermal propagation phenomenon is triggered by heat transfer from the gas and flames.

[0006] The internal pressure of the battery pack increases due to heat propagation generated within the pack. The pack case, which houses multiple battery modules, can withstand a certain amount of internal pressure and resist structural deformation; however, as thermal runaway and heat propagation progress, the internal pressure rises to a level that the pack case can no longer handle.

[0007] If the internal pressure rises above the structural rigidity limit of the pack case, the seams of the pack case will eventually separate. High-temperature, high-pressure dust, gases, and flames will then be ejected through these gaps, potentially causing a fire around the battery pack. Therefore, higher structural rigidity of the pack case is advantageous for delaying the spread of heat to the outside of the battery pack.

[0008] To ensure the excellent structural rigidity of such pack cases, they can be constructed from thicker and stronger materials, or manufactured in a form that minimizes seams, such as by machining metal blocks. However, these methods drastically increase production costs, and if the weight increases excessively, there are limitations to their application in fields where self-weight is critical, such as automotive batteries. Prior art literature

[0009] Chinese Utility Model Registration No. 211605235 (Published September 29, 2020) The problem to be solved

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

[0011] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description of the invention below. means of solving the problem

[0012] The present invention relates to a pack case, comprising, in one example, a base plate forming a bottom surface; side beams each coupled along the front, rear, left, and right corners of the base plate to form a receiving space; an upper cover coupled to the side beams to cover the upper surface of the receiving space; and a lead bracket coupled to the upper cover and the side beams.

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

[0014] And, the lead bracket may be provided one per side beam.

[0015] In addition, the lead bracket can be joined to the upper cover and the side beam by a detachable fastening member or by welding.

[0016] In addition, the lead bracket can be fixed collectively to the side beam by means of a fastening member together with the upper cover.

[0017] In addition, a gasket may be interposed between the contact surface of the side beam and the upper cover.

[0018] Meanwhile, according to another embodiment of the present invention, the side beams further include a corner bracket that is joined along the height direction of the corners that meet each other.

[0019] The above corner bracket can be formed in a bent shape that contacts all of the side beams that meet each other.

[0020] In addition, the corner bracket can be joined to the side beam by a detachable fastening member or by welding.

[0021] In addition, heat-resistant silicone may be interposed on the contact surface between the side beams.

[0022] In addition, a brazing material may be interposed on the contact surface between the corner bracket and the side beam. Effects of the invention

[0023] The pack case of the present invention, having the above-described configuration, more effectively suppresses leakage of dust or gas, etc., even when the internal pressure rises excessively due to the emission of a large amount of conductive dust, gas, and flames caused by thermal runaway occurring in the battery module mounted in the receiving space, by reinforcing the fixing force of the upper cover and / or side beam by the lead bracket and / or corner bracket.

[0024] In particular, the present invention has the advantage of not placing an excessive burden on manufacturing costs, process efficiency, or battery pack weight increase, as the pressure resistance performance of the pack case can be improved simply by adding a folded lead bracket and / or corner bracket without constructing the pack case with a thicker and stronger material.

[0025] However, the technical effects obtainable through the present invention are not limited to those described above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description of the invention below. Brief explanation of the drawing

[0026] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a drawing illustrating one embodiment of a pack case according to the present invention. FIG. 2 is a drawing illustrating an embodiment of mounting a lead bracket. FIG. 3 is a cross-sectional view illustrating the mounting structure of a lead bracket. FIG. 4 is a drawing illustrating an embodiment of mounting a corner bracket. FIG. 5 is a drawing showing a state in which a corner bracket is mounted between side beams. FIG. 6 is a cross-sectional view illustrating an embodiment in which heat-resistant silicone is interposed between side beams. FIG. 7 is a cross-sectional view illustrating an embodiment in which a brazing material is interposed between a corner bracket and a side beam. Specific details for implementing the invention

[0027] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are to be described in detail below.

[0028] However, this is not intended to limit the invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0029] In the present invention, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0030] Furthermore, in the present invention, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only cases where it is "immediately above" the other part, but also cases where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only cases where it is "immediately below" the other part, but also cases where there is another part in between. Additionally, in the present application, being "placed on" may include cases where it is placed on the lower part as well as on the upper part.

[0032] The present invention relates to a pack case, and in one example, comprises a base plate forming a bottom surface, side beams each coupled along the front, rear, left, and right corners of the base plate to form a receiving space, an upper cover coupled to the side beams to cover the upper surface of the receiving space, and a lid bracket coupled to the upper cover and the side beams.

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

[0034] The pack case of the present invention, having such a configuration, more effectively suppresses leakage of dust, etc., even when the internal pressure rises excessively due to the emission of a large amount of conductive dust, gas, and flames caused by thermal runaway occurring in the battery module mounted in the receiving space, by reinforcing the fixing force of the upper cover by the lead bracket.

[0035] In particular, the present invention has the advantage of not placing an excessive burden on manufacturing costs, process efficiency, or battery pack weight increase, as the pressure resistance performance of the pack case can be improved simply by adding a folded lead bracket without constructing the pack case with a thicker and stronger material.

[0037] Hereinafter, specific embodiments of the pack case according to the present invention will be described in detail with reference to the attached drawings. For reference, the directions of front, back, up, down, left, and right used to specify relative positions in the following description are intended to aid in understanding the invention, and unless otherwise specifically defined, the directions shown in the drawings are used as the reference.

[0039] [First embodiment]

[0040] FIG. 1 is a drawing illustrating 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) that accommodates a plurality of battery modules (200). The pack case (100) is constructed as a frame structure that can secure structural rigidity of the battery pack (10) while protecting the mounted battery modules (200) and forming a space for accommodating a plurality of battery modules (200). The battery pack (10) illustrated exemplarily in FIG. 1 accommodates a total of eight battery modules (200) and is arranged so that the front of the battery modules (200) faces toward a center beam (130) that crosses the center of the pack case (100). A high-voltage terminal for connecting a bus bar is arranged on the front of the battery module (200), and a thermal barrier (210) for protecting it is mounted on the battery module (200).

[0041] The pack case (100) includes a base plate (110) forming a bottom surface and side beams (120) that are respectively connected along the front, rear, left, and right corners of the base plate (110) to form a receiving space. Four side beams (120) are provided to form a cuboid-shaped pack case (100). 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, according to the positioning of the front and rear defined for the battery pack (10).

[0042] Additionally, the pack case (100) includes an upper cover (140) coupled to a side beam (120) to cover the upper surface of a receiving space in which a battery module (200) is mounted. A gasket (150) may be interposed between the side cover and the upper cover (140) to seal the contact surface between them.

[0043] Conventional pack cases use a fastening member (500), such as the bolt shown in FIG. 1, to detach the upper cover (140) from the side beam (120). The bolt passes through a fastening hole (142) formed in the upper cover (140) and is fastened to a screw hole (122) formed on the upper surface of the side beam (120).

[0044] According to this conventional structure, when the battery module (200) is operating normally, the fixing force of the fastening member (500) provides sufficient sealing force to the gasket (150), thereby ensuring the airtightness of the battery pack is faithfully maintained. However, if the internal pressure of the pack case (100) increases due to thermal runaway in the battery module (200), the fixing force of the fastening member (500) weakens due to the pressure, and a gap is created between the gaskets (150), causing dust, gas, and flames to be ejected to the outside. In addition, a problem arises in which the flame inside the pack case (100) grows more intensely as oxygen is supplied through the gap created in the upper cover (140).

[0045] The pack case (100) of the present invention includes a lead bracket (300) for reinforcing the fixing force of the upper cover (140). The lead bracket (300) is coupled to the upper cover (140) and the side beam (120). In the illustrated embodiment, the lead 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 lead bracket (300) in this bent shape provides additional fixing force to the upper cover (140) by having one bent surface coupled to the upper cover (140) and the other bent surface coupled to the side beam (120) along the edge of the pack case (100) where the upper cover (140) and the side beam (120) meet.

[0046] Due to the additional fixing force provided by the lead bracket (300), even when the internal pressure of the pack case (100) rises excessively, the seal between the upper cover (140) and the gasket (150) is maintained well, thereby more effectively suppressing or delaying the leakage of dust or gas.

[0047] In addition, since the weight and volume of the lead bracket (300) itself are not very large, the pressure resistance performance of the pack case (100) can be improved simply by adding a folded lead bracket (300) without constructing the pack case (100) with a thicker and stronger material, so there is no excessive burden in terms of manufacturing costs, process efficiency, or weight increase of the battery pack (10).

[0048] FIG. 2 is a drawing illustrating an embodiment of mounting a lead bracket (300). Referring to FIG. 2, a lead bracket (300) is provided for each side beam (120). Since the lead bracket (300) has a bent shape, it may be advantageous to assign a lead bracket (300) to each side beam (120) rather than manufacturing it in a form where one side beam (120) is joined across a plurality of side beams (120).

[0049] FIG. 3 is a cross-sectional view illustrating the mounting structure of a lead bracket (300). As described above, the lead bracket (300) can be connected to the upper cover (140) and the side beam (120) using a detachable fastening member (500), such as a bolt as shown in the drawing. In addition to this fastening member (500), the lead bracket (300) can also be mounted using welding. However, using a detachable fastening member (500) has the advantage of making it easy to maintain and repair the inside of the battery pack (10) by removing the lead bracket (300) and the upper cover (140). It is also advantageous in that workability is improved because the lead bracket (300) can be fixed to the side beam (120) together with the upper cover (140) using the fastening member (500) as shown in FIG. 3.

[0051] [Second embodiment]

[0052] A second embodiment of the present invention is an embodiment capable of further enhancing the pressure resistance of the pack case (100), and further includes a corner bracket (400) that reinforces the fastening structure between the side beams (120).

[0053] FIG. 4 is a drawing illustrating an embodiment of mounting a corner bracket (400), wherein the corner bracket (400) is joined along the height direction of the corners where the side beams (120) meet each other. Since the contact surface between the side beams (120) is not very large, a separate gasket is generally not installed, but when the internal pressure rises due to thermal runaway, the side beams (120) become loose and dust and gas are ejected.

[0054] To prevent leakage between these side beams (120), a corner bracket (400) is installed. The corner bracket (400) has a bent shape that contacts both side beams (120) that meet each other on both sides, and strengthens the fixing force between the side beams (120) by joining along the height direction of the corners where the side beams (120) meet each other.

[0055] FIG. 5 is a drawing showing a state in which a corner bracket (400) is mounted between side beams (120). As the fixing force between the side beams (120) is improved, the side beams (120) do not easily separate even when strong internal pressure is applied, and thus the ejection of dust and gas between the side beams (120) is suppressed.

[0056] Also, although FIGS. 4 and 5 show that the corner bracket (400) is connected to the side beam (120) by a detachable fastening member (500), as described in the first embodiment, it is also possible to connect the corner bracket (400) to the side beam (120) by welding.

[0057] FIG. 6 is a cross-sectional view illustrating an embodiment in which heat-resistant silicone (600) is interposed between side beams (120). In addition to improving the fixability of the height-direction corners of the pack case (100) with corner brackets (400), heat-resistant silicone (600) may be interposed on the contact surfaces between the side beams (120). Due to the heat-resistant silicone (600), the close contact between the side beams (120) is maintained well even in a high-temperature environment, thereby further suppressing the leakage of the discharge from the battery module (200).

[0058] Additionally, 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, brazing treatment can be performed on the contact surface between the corner bracket (400) and the side beam (120). By inserting a thin brazing material into the inner surface of the corner bracket (400) and fastening it to the side beam (120), and then applying heat at an appropriate temperature, the brazing material (610) can be interposed on the contact surface between the corner bracket (400) and the side beam (120). After the brazing material (610) melts and fills the gap and then solidifies, the fixing force of the corner bracket (400) is further strengthened, and the airtightness is also improved.

[0060] The present invention has been described in more detail above through drawings and embodiments. However, the configurations described in the drawings or embodiments described in this specification are merely one embodiment of the present invention and do not represent all technical concepts of the present invention; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application. Explanation of the symbols

[0061] 10: Battery Pack 100: Pack Case 110: Base plate 120: Side beam 122: Screw hole 130: Center beam 140: Upper cover 142: Fastening hole 150: Gasket 200: Battery Module 210: Thermal Barrier 300: Lead Bracket 400: Corner bracket 500: Fastening member 600: Heat-resistant silicone 610: Brazing material

Claims

Claim 1 A pack case comprising: a base plate forming a bottom surface; side beams formed by being joined along the front, rear, left, and right corners of the base plate to form a receiving space; an upper cover joined to the side beams to cover the upper surface of the receiving space; and a lead bracket joined to the upper cover and the side beams; wherein the lead bracket has a bent shape that contacts both the edge of the upper cover and the upper corner of the side beams, and the lead bracket is joined to the upper cover and the side beams, respectively, by a detachable fastening member or by welding. Claim 2 delete Claim 3 A pack case according to claim 1, characterized in that the lead bracket is provided one per side beam. Claim 4 delete Claim 5 A pack case according to claim 1, characterized in that the lead bracket is fixed collectively to the side beam by a fastening member together with the upper cover. Claim 6 A pack case according to claim 1, characterized in that a gasket is interposed between the contact surface of the side beam and the upper cover. Claim 7 A pack case according to claim 1, further comprising a corner bracket that joins the side beams along the height direction of the corners that meet each other. Claim 8 A pack case according to claim 7, characterized in that the corner bracket has a bent shape that contacts all of the side beams that meet each other. Claim 9 A pack case according to claim 8, wherein the corner bracket is joined to the side beam by a detachable fastening member or by welding. Claim 10 A pack case characterized in that, in claim 8, heat-resistant silicone is interposed between the contact surfaces of the side beams. Claim 11 A pack case according to claim 7, characterized in that a brazing material is interposed between the corner bracket and the side beam in the contact surface.

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