Battery module with improved heat dissipation structure

Abstract

The disclosed invention relates to a battery module, which in one example includes a plurality of battery cells and a module case that houses the plurality of battery cells, and a plurality of recessed structures are formed on the outer surface of a lower frame of the module case, and the plurality of recessed structures form a space that houses a thermal resin.

Description

【Technical Field】 【0001】 The present invention relates to a battery module that improves the heat dissipation performance of a battery pack by promoting conductive heat transfer transmitted from a battery module to a pack case. 【0002】 This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0026624 filed on February 28, 2023, and all the contents disclosed in the documents of the Korean patent application are incorporated herein by reference. 【Background Art】 【0003】 A secondary battery is rechargeable, unlike a primary battery, and has been extensively researched and developed in recent years due to its potential for miniaturization and high capacity. With the increasing development of technology and demand for mobile devices, as well as the emergence of electric vehicles and energy storage systems in line with the contemporary requirements of environmental protection, the demand for secondary batteries as an energy source has been increasing even more rapidly. 【0004】 Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries according to the shape of the battery case. The electrode assembly installed inside the battery case in a secondary battery is a power generation element capable of charge and discharge, which has a laminated structure of electrodes and a separator. 【0005】 Since secondary batteries are required to be used continuously for a long period of time, it is necessary to effectively control the heat generated during the charge and discharge process. If the cooling of the secondary battery is not smoothly performed, an increase in temperature causes an increase in current, and a chain reaction occurs in which the increase in current causes a further increase in temperature, resulting in a catastrophic state of thermal runaway. 【0006】 Furthermore, when secondary batteries are arranged in a group in the form of modules or packs, a thermal runaway in one secondary battery can cause a thermal propagation phenomenon in which surrounding secondary batteries continuously overheat. In other words, when a 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 terminals of the battery module. This causes dust to accumulate on the high-voltage terminals of adjacent battery modules, and the heat transfer from the gas and flames triggers the thermal propagation phenomenon. 【0007】 To prevent or delay heat transfer from a battery cell or module experiencing thermal runaway to an adjacent battery cell or module, the following designs are applied: an insulating design that uses insulating material to prevent or delay heat transfer from the battery module experiencing thermal runaway to an adjacent battery module, and a heat dissipation design that quickly and initially releases the heat from the battery module experiencing thermal runaway to the outside of the battery pack, thereby reducing heat transfer to an adjacent battery module. 【0008】 Suppressing and delaying heat transfer is a critical issue, especially in electric vehicles where it directly impacts human life, and related regulations are being strengthened daily. Specifically, they require a sufficient delay time before heat transfer dissipates, ensuring enough time for emergency evacuation and safety measures after a thermal runaway occurs. Therefore, there is a real need for more effective methods to suppress or delay heat transfer in battery packs. [Overview of the Initiative] [Problems that the invention aims to solve] 【0009】 The present invention aims to provide a battery module that, in order to suppress and delay heat propagation, rapidly transfers heat generated from a battery module experiencing thermal runaway to the pack case via conductive heat transfer, thereby enabling rapid release to the outside as convective heat transfer within the pack case. 【0010】 However, the technical problems that the present invention aims to solve are not limited to those described above, and other problems not mentioned can be clearly understood by an ordinary person of the art from the description of the invention below. [Means for solving the problem] 【0011】 The present invention relates to a battery module, which in one example includes a plurality of battery cells and a module case housing the plurality of battery cells, wherein a plurality of engraved structures are formed on the outer surface of the lower frame of the module case, and the plurality of engraved structures form a space for housing thermal resin. 【0012】 In one embodiment of the present invention, the engraved structure may form a grid structure uniformly arranged vertically and horizontally on the outer surface of the lower frame. 【0013】 The above-described incised structure increases the heat transfer area of ​​the lower frame to the thermal resin filled inside, compared to a flat surface. 【0014】 In exemplary embodiments, the engraved structure may form a curved surface including a hemisphere and a semi-ellipsoid. 【0015】 Alternatively, the above-described incised structure may form a honeycomb structure. 【0016】 On the other hand, the present invention provides a battery pack comprising a plurality of battery modules having the above configuration, a pack case housing the plurality of battery modules, and a thermal resin applied between the lower frame of the battery module and the base plate of the pack case, wherein the thermal resin is filled into a plurality of incised structures formed on the outer surface of the lower frame of the module case. 【0017】 In the battery pack of the present invention, the area of ​​conductive heat transfer flowing from the thermal resin filled in the engraved structure to the base plate is increased compared to planar contact. 【0018】 Furthermore, the battery pack of the present invention includes a pack case which includes partition members that separate the plurality of battery modules from each other, and the base plate which may have slots formed through the region that contacts the partition members. 【0019】 In one embodiment, it is preferable that the slot is not exposed to the outside of the partition member. 【0020】 Furthermore, multiple slots may be formed at intervals along the partition wall member. [Effects of the Invention] 【0021】 The battery module of the present invention, having the configuration described above, has an incised structure provided on the lower frame of the module case that provides an expanded heat transfer area to the thermal resin. This expanded heat transfer area increases the amount of heat conducted from the battery module to the base plate. As a result, heat from the battery module experiencing thermal runaway is quickly transferred to the base plate and dissipated to the outside of the battery pack, thus contributing to the suppression or delay of heat propagation. 【0022】 Furthermore, the slots formed through the base plate along the partition members that form boundaries between battery modules physically remove a portion of the heat conduction path between battery modules. This not only reduces and delays excessive heat transfer caused by battery modules experiencing thermal runaway, but also further promotes heat dissipation on the base plate. 【0023】 However, the technical effects that can be obtained by the present invention are not limited to those described above, and other effects not mentioned can be clearly understood by an ordinary person of the art from the description of the invention below. 【0024】 The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention to be described later. Therefore, the present invention should not be construed as being limited only to the matters described in such drawings. 【Brief Description of the Drawings】 【0025】 [Figure 1] It is a drawing showing a battery module according to the present invention. [Figure 2] It is a drawing showing the outer surface of the lower frame of the module case. [Figure 3] It is a cross-sectional view taken along the line "A - A" of FIG. 2. [Figure 4] It is a drawing showing another embodiment of the lower frame of the module case. [Figure 5] It is a drawing showing a battery pack according to the present invention. [Figure 6] It is a cross-sectional view showing the contact surface between the battery module and the base plate. [Figure 7] It is a drawing showing the conduction heat transfer path in the battery pack of FIG. 6. [Figure 8] It is a drawing showing another embodiment of the pack case. [Figure 9] It is a drawing showing the conduction heat transfer path in the battery pack of FIG. 8. [[ID=3S]]【Embodiments for Carrying Out the Invention】 【0026】 Since the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described in detail below. 【0027】 However, this is not intended to limit the present invention to specific embodiments, and it can be understood to include all modifications, equivalents or alternatives included in the spirit and technical scope of the present invention. 【0028】 In the present invention, terms such as "includes" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof as described in the specification, and do not preemptively exclude the presence or possibility of adding one or more other features, numbers, steps, operations, components, parts, or combinations thereof. 【0029】 Furthermore, in this invention, when a part such as a layer, film, region, or plate is described as being "on top" of another part, this includes not only the case where it is "directly on top" of the other part, but also the case where another part is located in between. Conversely, when a part such as a layer, film, region, or plate is described as being "below" another part, this includes not only the case where it is "directly below" the other part, but also the case where another part is located in between. Also, in this application, being "on top" may include being located not only at the top but also at the bottom. 【0030】 The present invention relates to a battery module, which in one example includes a plurality of battery cells and a module case housing the plurality of battery cells, wherein a plurality of engraved structures are formed on the outer surface of the lower frame of the module case, and the plurality of engraved structures form a space for housing thermal resin. 【0031】 Here, the engraved structure increases the heat transfer area of ​​the lower frame to the thermal resin filled inside it, compared to a flat surface. 【0032】 As a result, the battery module of the present invention, from the viewpoint of heat dissipation design, can rapidly transfer heat generated in a battery module that has experienced thermal runaway to the pack case in the form of conductive heat transfer due to the increased heat transfer area to the thermal resin. Consequently, a large amount of heat is transferred to the pack case early, and the amount of heat released to the outside as convective heat transfer increases, thereby effectively suppressing or delaying heat propagation within the battery pack. 【0033】 Specific embodiments of the battery module 200 according to the present invention will be described in detail below with reference to the attached drawings. For reference, the forward / backward and up / down / left / right directions used in the following description to specify relative positions are for the purpose of aiding the understanding of the invention, and unless otherwise defined, the directions shown in the drawings are used as the reference. 【0034】 (First Embodiment) Figure 1 is a drawing showing a battery module 200 according to the present invention, and Figure 2 is a drawing showing the outer surface of the lower frame 222 of the module case 220. 【0035】 Referring to Figures 1 and 2, the battery module 200 broadly includes a plurality of battery cells 210 and a module case 220 that houses the plurality of battery cells 210. In addition, the battery module 200 may include accessories such as insulating material for heat insulation between the battery cells 210 and a busbar frame assembly (BFA) for electrical connection between the plurality of battery cells 210 and external output, but such accessories are not directly related to the heat dissipation design of the battery module 200 according to the present invention, so a description thereof will be omitted. 【0036】 Figure 2, which shows the bottom surface of the module case 220, shows that multiple engraved structures 230 are formed on the outer surface of the lower frame 222 of the module case 220. The multiple engraved structures 230 can form a grid structure that is uniformly arranged vertically and horizontally on the outer surface of the lower frame 222, and each engraved structure 230 forms a concave space. 【0037】 The multiple engraved structures 230 can be manufactured by applying any one of the known processing techniques, such as press working, mechanical cutting, plasma processing, electrolytic processing, etching, and casting. The multiple engraved structures 230 can be processed so that the corresponding engraved structures protrude into the interior of the lower frame 222, but this may adversely affect the capacity of the battery module 200, so it is preferable that the inner surface of the lower frame 222 be flat. 【0038】 In this invention, the multiple engraved structures 230 form spaces for housing thermal resin 300. The battery module 200 is housed in the pack case 100 to complete the battery pack 10, but the base plate 110 forming the bottom surface of the pack case 100 and the lower frame 222 of the module case 220 are in contact with each other, and conductive heat transfer occurs. To promote conductive heat transfer, thermal resin 300, which has excellent thermal conductivity, is interposed at the contact surface between the base plate 110 and the module case 220. 【0039】 When thermal runaway occurs in a battery module 200 within the battery pack 10, heat is transferred to adjacent battery modules 200 along the base plate 110, where conductive heat transfer is active. On the other hand, the base plate 110 is often provided with heat dissipation means such as cooling channels 114. Therefore, within the pack case 100, before the heat from the battery module 200 diffuses to other sides other than the base plate 110 by convective heat transfer, it may be advantageous to increase the amount of heat dissipated to the outside of the battery pack 10 by conducting the heat from the thermally runaway battery module 200 to the base plate 110 as quickly as possible, thereby suppressing or delaying heat transfer. 【0040】 From this heat dissipation perspective, the engraved structure 230 provided on the lower frame 222 of the module case 220 provides an expanded heat transfer area to the thermal resin 300. Figure 3 is a cross-sectional view taken along the line "AA" in Figure 2, and as shown in the drawing, the thermal resin 300 filled in the concave engraved structure 230 is provided with a wider heat transfer surface to the battery module 200 compared to a flat contact surface. 【0041】 The amount of heat conducted from the battery module 200 to the base plate 110 increases proportionally through the expanded heat transfer area provided by the engraved structure 230. As a result, the heat from the battery module 200 experiencing thermal runaway is quickly transferred to the base plate 110, giving it an opportunity to be dissipated to the outside of the battery pack 10. Therefore, the numerous engraved structures 230 formed on the bottom surface of the battery module 200 contribute to suppressing or delaying heat propagation through the thermal resin 300. 【0042】 In the exemplary embodiment shown in Figure 3, the engraved structure 230 has a curved surface including hemispheres and semiellipsoids. This is because curved surfaces are advantageous surface morphologies for expanding the heat transfer area. Alternatively, as shown in Figure 4, the engraved structure 230 can also have a honeycomb structure. While the honeycomb structure may be somewhat less effective than the case in Figure 3 in terms of expanding the heat transfer area, it can be effective in complementing or strengthening the structural rigidity of the lower frame 222, which may be weakened by the engraved structure 230. 【0043】 (Second Embodiment) Figure 5 is a drawing showing a battery pack 10 according to the present invention. Multiple battery modules 200 described in the first embodiment are housed in a pack case 100. The illustrated pack case 100 includes a base plate 110 forming the bottom surface, side plates 120 surrounding the outer casing of the base plate 110, partition members 130 arranged vertically and / or horizontally to partition the housing space defined by the side plates 120, and a lid 160 closing the top surface of the housing space. The base plate 110 is provided with cooling channels 114 through which cooling fluid is stored or flows. However, although Figure 5 shows the base plate 110 with cooling channels 114, it is also possible for a separate cooling plate (not shown) to be joined to the base plate 110. 【0044】 Here, the partition member 130 can also be distinguished into a vertical center beam 140 that crosses the center of the pack case 100 and divides the internal storage space into left and right sections, and a horizontal cross beam 150 that forms a grid shape with respect to the center beam 140, depending on the direction of arrangement relative to the base plate 110. 【0045】 Figure 6 is a cross-sectional view showing the contact surface between the battery module 200 and the base plate 110. The battery pack 10 in Figure 6 includes thermal resin 300 which is applied between the lower frame 222 of the battery module 200 and the base plate 110 of the pack case 100. As a result, the thermal resin 300 fills the multiple incised structures 230 formed on the outer surface of the lower frame 222 of the module case 220. 【0046】 As described in the first embodiment, the engraved structure 230 provided on the lower frame 222 of the module case 220 provides an expanded heat transfer area to the thermal resin 300, and the amount of heat conducted from the battery module 200 to the base plate 110 increases proportionally to the expansion of the heat transfer area on the module case 220. Figure 7 is a diagram showing the conductive heat transfer path in the battery pack 10 of Figure 6. Assuming that the illustrated battery module 200 experiences thermal runaway, the large amount of heat generated by the thermal runaway is conducted and transferred to the base plate 110 in greater quantities due to the increased heat transfer area provided by the engraved structure 230. A large amount of the heat transferred to the base plate 110 is released to the outside of the battery pack 10 via the base plate 110 and the cooling fluid, thereby reducing the amount of heat that is transmitted to other surrounding battery modules 200 using the base plate 110 as a heat conduction medium. This improvement in heat dissipation performance contributes to suppressing and delaying heat propagation within the battery pack 10. 【0047】 Figure 8 is a drawing showing another embodiment of the pack case 100. In the embodiment of the pack case 100 shown in Figure 8, the pack case 100 includes a partition member 130 that separates a plurality of battery modules 200 from each other, while the base plate 110 has a slot 112 formed through the region that contacts the partition member 130. The slot 112 formed through the base plate 110 is a structure for limiting conductive heat transfer that occurs across the bottom surface of the partition member 130. 【0048】 The partition members 130 forming the center beam 140 and / or cross beam 150 form a boundary between the battery modules 200, but conductive heat transfer propagating across the partition members 130 to adjacent battery modules 200 is limited by slots 112 formed through the base plate 110. That is, as shown in Figure 9, a portion of the heat conduction path between the battery modules 200 via the base plate 110 is physically removed by slots 112 formed through the base plate 110, thereby reducing and delaying excessive heat transfer caused by a battery module 200 experiencing thermal runaway. For reference, if cooling channels 114 are provided in the base plate 110, the slot 112 structure needs to be formed to avoid the cooling channels 114. 【0049】 In other respects, the through-slots 112 in the base plate 110 also serve to promote heat dissipation by convection. In other words, conductive heat transfer that propagates across the partition member 130 to the adjacent battery module 200 is restricted and delayed by the through-slots 112 formed in the base plate 110, and as a result, the base plate 110 has more opportunities for heat dissipation. 【0050】 In one embodiment, it is preferable that the slots 112, which are arranged alongside the partition member 130, are not exposed to the outside of the partition member 130. To ensure that conductive heat transfer is reliably limited, the slots 112 are formed through the base plate 110, but these through-formed slots 112 affect the airtightness of the pack case 100. Therefore, the airtightness of the pack case 100 can be ensured by designing the size of the slots 112 such that the partition member 130 completely surrounds the slots 112 so as to close the slots 112 formed through the base plate 110. 【0051】 Furthermore, multiple slots 112 can be formed at intervals along the partition member 130. Conductive heat transfer occurs in the regions between the spaced-apart slots 112, but when multiple slots 112 are formed at intervals, preferably evenly spaced, the heat conducted to adjacent battery modules 200 is not locally concentrated, which can be advantageous in preventing further thermal runaway. 【0052】 The present invention has been described in more detail above through the drawings and embodiments. However, the configurations described in the drawings or embodiments described herein are merely one embodiment of the present invention and do not represent the entire technical concept of the present invention. Therefore, there may be various equivalents and modifications that can substitute for them at the time of filing. [Explanation of symbols] 【0053】 10: Battery Pack 100: Pack Case 110: Base plate 112: Slot 114: Cooling Channel 120: Side Plate 130: Partition member 140: Center beam 150: Crossbeam 160: Lid 200: Battery Module 210: Battery cell 220: Module Case 222: Lower frame 230: Intaglio structure 300: Thermal Resin

Claims

[Claim 1] Multiple battery cells, A module case housing the aforementioned plurality of battery cells, A battery module in which multiple incised structures are formed on the outer surface of the lower frame of the module case, each forming a concave space, the inner surface of the lower frame is a flat surface, and the multiple incised structures form spaces for housing thermal resin. [Claim 2] The aforementioned incised structure is The battery module according to claim 1, wherein the lattice structure is uniformly arranged vertically and horizontally on the outer surface of the lower frame. [Claim 3] The aforementioned incised structure is The battery module according to claim 1, wherein the heat transfer area of ​​the lower frame to the thermal resin filled inside is increased compared to a flat surface. [Claim 4] The aforementioned incised structure is The battery module according to claim 1, having a curved surface including a hemisphere and a semi-ellipsoid. [Claim 5] The aforementioned incised structure is The battery module according to claim 2, having a honeycomb structure. [Claim 6] A plurality of battery modules according to any one of claims 1 to 5, A pack case for housing the aforementioned multiple battery modules, The thermal resin is applied between the lower frame of the battery module and the base plate of the pack case, A battery pack in which the thermal resin is filled into a plurality of engraved structures formed on the outer surface of the lower frame of the module case. [Claim 7] The battery pack according to claim 6, wherein the area of ​​conductive heat transfer flowing to the base plate via the thermal resin filled in the engraved structure is increased compared to planar contact. [Claim 8] The pack case includes partition members that separate the plurality of battery modules from each other. The battery pack according to claim 6, wherein the base plate has a slot formed through it in a region that contacts the partition member. [Claim 9] The aforementioned slot is The battery pack according to claim 8, wherein the partition member is not exposed to the outside. [Claim 10] The aforementioned slot is The battery pack according to claim 8, wherein a plurality of units are formed spaced apart along the partition wall member.

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