Battery assembly and battery pack including the same

Abstract

A battery assembly according to one embodiment of the present invention includes a plurality of battery cell units, each including at least one battery cell and a cell cover covering a bottom surface and both side surfaces of the at least one battery cell, wherein the cell cover includes at least one cell cover venting hole in a bottom surface portion corresponding to the bottom surface of the battery cell, electrode leads protruding from both longitudinal end surfaces of the battery cell, and a foam layer disposed adjacent to at least one electrode lead of the at least one battery cell.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0172420 filed on December 1, 2023, and Korean Patent Application No. 10-2024-0162319 filed on November 14, 2024, and all contents disclosed in the documents of these Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery assembly and a battery pack including the same, and more particularly to a battery assembly and a battery pack including the same that improve safety by inducing gas venting in a desired direction in a thermal runaway situation. [Background technology]

[0003] In modern society, the use of portable devices such as mobile phones, laptops, video cameras, and digital cameras has become commonplace, leading to active development of technologies related to these mobile devices. Furthermore, rechargeable secondary batteries are being used as the power source for electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (P-HEVs), as a solution to address air pollution caused by conventional gasoline-powered vehicles that use fossil fuels, and there is an increasing need for the development of secondary batteries.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Of these, lithium secondary batteries are attracting attention due to their advantages over nickel-based secondary batteries, such as almost no memory effect, freedom in charging and discharging, extremely low self-discharge rate, and high energy density.

[0005] Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as positive and negative electrode active materials, respectively, and include an electrode assembly in which positive and negative electrode plates coated with the positive and negative electrode active materials are disposed with a separator between them, and a battery case that hermetically houses the electrode assembly together with an electrolyte.

[0006] Generally, lithium secondary batteries can be classified into can-type secondary batteries, in which an electrode assembly is housed in a metal can, and pouch-type secondary batteries, in which an electrode assembly is housed in a pouch made of an aluminum laminate sheet, depending on the shape of the exterior material.

[0007] Secondary batteries used in small devices typically have two to three battery cells, while secondary batteries used in medium- to large-sized devices such as automobiles typically use battery modules in which multiple battery cells are electrically connected. These battery modules improve capacity and output by connecting multiple battery cells in series or parallel to each other to form a stack of battery cells. One or more battery modules may be installed with various control and protection systems, such as a battery management system (BMS), a battery disconnect unit (BDU), and a cooling system, to form a battery pack.

[0008] A battery pack includes a battery module as a sub-concept, and a battery module includes a battery cell as a sub-concept. The number of battery cells in a battery module or the number of battery modules in a battery pack can be determined in various ways depending on the output and capacity of the battery pack required for the electric vehicle.

[0009] However, one of the most important issues in such battery packs is safety. In particular, if a thermal event occurs in one of the many battery cells included in the battery pack, it is necessary to prevent the propagation of the thermal event to other battery cells and modules.

[0010] If thermal propagation between battery cells and modules is not properly suppressed, it may lead to thermal events in other battery cells included in the battery pack, which may cause larger problems such as fire or explosion of the battery pack. Furthermore, fire or explosion occurring in the battery pack may cause significant damage to surrounding lives and property. Therefore, for such battery packs, a configuration that can properly control the above-mentioned thermal events and the propagation of such thermal events is required. Summary of the Invention [Problem to be solved by the invention]

[0011] The problem to be solved by the present invention is to provide a battery assembly and a battery pack including the same that, when a thermal event occurs in a specific battery cell, can prevent the heat transfer event from propagating to other adjacent battery cells and battery assemblies by venting venting gas, particles, flames, etc. only in a specific intended direction, thereby moving them along a predetermined path and discharging them to the outside.

[0012] However, the problems to be solved by the embodiments of the present invention are not limited to the above-mentioned problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0013] A battery assembly according to one embodiment of the present invention includes a plurality of battery cell units, each including at least one battery cell and a cell cover covering a bottom surface and both side surfaces of the at least one battery cell, wherein the cell cover includes at least one cell cover venting hole in a bottom surface portion corresponding to the bottom surface of the battery cell, electrode leads protruding from both end surfaces in a length direction of the battery cell, and a foam layer disposed adjacent to the electrode leads of the at least one battery cell.

[0014] The cell cover includes openings on both sides that expose the electrode leads, and the foam layer expands in volume at high temperatures to close the openings on both sides.

[0015] The battery assembly may further include a first thermally conductive resin layer disposed on an upper portion of the battery cell.

[0016] The cell cover may include side portions that extend vertically from the bottom portion and correspond to both side surfaces of the battery cell, and upper ends of the side portions may be in contact with the first thermally conductive resin layer.

[0017] The battery assembly may further include an anti-blocking bump disposed adjacent to a cell cover venting hole adjacent to the electrode lead among the at least one cell cover venting hole.

[0018] The battery assembly may further include a storage frame that stores the plurality of battery cell units, and the storage frame may include at least one vent hole formed in a lower surface of the storage frame at a position corresponding to the cell cover vent hole.

[0019] A battery pack according to an embodiment of the present invention includes the battery assembly and a pack housing that houses the battery assembly.

[0020] The battery pack may further include a plurality of venting channels communicating with the cell cover venting holes and extending from an interior of the bottom frame of the pack housing.

[0021] Each of the venting channels may be in communication with each of the battery cell units in a one-to-one relationship.

[0022] The battery assembly may further include a receiving frame that receives the plurality of battery cell units and includes at least one venting hole formed at a position corresponding to the cell cover venting hole, and the venting channel may be in communication with the venting hole.

[0023] The battery assembly may further include a first thermally conductive resin layer disposed between an upper portion of the battery cell and an upper surface of the storage frame, and the battery pack may further include a pack cover disposed outside the storage frame and coupled to an upper portion of the pack housing.

[0024] The battery pack may further include a second thermally conductive resin layer disposed between the pack cover and the upper surface of the storage frame. [Effects of the Invention]

[0025] According to an embodiment of the present invention, when a thermal event occurs in a specific battery cell, venting gas, particles, flames, etc. can be vented only in a specific intended direction, allowing them to travel along a predetermined path and be discharged to the outside, thereby minimizing the propagation of the thermal event to other adjacent battery cells and battery assemblies.

[0026] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a perspective view showing a battery assembly according to an embodiment of the present invention; [Figure 2] FIG. 2 is an exploded perspective view of the battery assembly of FIG. 1. [Figure 3] 3 is a plan view showing a battery cell included in the battery assembly of FIG. 2. FIG. [Figure 4] 4 is a perspective view showing a battery cell stack included in the battery assembly of FIG. 2 and including the battery cell of FIG. 3. [Figure 5] 5 is an exploded perspective view of a battery cell unit included in the battery cell stack of FIG. 4. FIG. [Figure 6] 6(a) is a perspective view of the cell cover of FIG. 5 seen from another angle, and FIG. 6(b) is a cross-sectional view showing a cross section cut along the cutting line AA' of FIG. 5. [Figure 7] FIG. 10 is an exploded perspective view of a battery cell unit included in a battery assembly according to another embodiment of the present invention. [Figure 8] FIG. 10 is an exploded perspective view showing a battery pack according to still another embodiment of the present invention. [Figure 9] 9 is a cross-sectional view showing a cross section taken along the line BB' in FIG. 8. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention may be embodied in various different forms and is not limited to the embodiments set forth herein.

[0029] In order to clearly describe the present invention, portions unnecessary for the explanation will be omitted and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0030] Furthermore, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are exaggerated to clearly show multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0031] Furthermore, when a layer, film, region, plate, or other part is said to be "on" or "above" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. Furthermore, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "above" or "above" the direction opposite to gravity.

[0032] Also, throughout the specification, when a part is said to "comprise" a certain element, this means that it may further include other elements, not excluding other elements, unless otherwise specified.

[0033] Also, throughout the specification, "in a plane" means when the subject part is viewed from above, and "in cross section" means when the subject part is cut vertically and viewed from the side.

[0034] Hereinafter, a battery assembly according to one embodiment of the present invention will be described with reference to FIGS.

[0035] FIG. 1 is a perspective view showing a battery assembly according to one embodiment of the present invention, FIG. 2 is an exploded perspective view of the battery assembly of FIG. 1, FIG. 3 is a plan view showing a battery cell included in the battery assembly of FIG. 2, FIG. 4 is a perspective view showing a battery cell stack included in the battery assembly of FIG. 2 and including the battery cell of FIG. 3, FIG. 5 is an exploded perspective view of a battery cell unit included in the battery cell stack of FIG. 4, FIG. 6(a) is a perspective view of the cell cover of FIG. 5 from another angle, and FIG. 6(b) is a cross-sectional view showing a cross-section cut along the cutting line A-A' of FIG. 5.

[0036] 1 to 5, the battery cells 110 according to this embodiment may be stacked in one direction to form a battery cell stack 110 A. The battery cells 110 will be described below.

[0037] The battery cell 110 according to this embodiment may be a battery cell of various shapes, such as a pouch-type battery cell, a prismatic battery cell, or a cylindrical battery cell. As an example, as shown in FIG. 3, the battery cell 110 according to this embodiment may be a pouch-type battery cell. While a pouch-type battery cell will be described below, the battery cell 110 according to this embodiment is not limited thereto, and various types of battery cells may be applied.

[0038] The battery cell 110 according to this embodiment may have a configuration in which an electrode assembly having electrode leads 111 protruding in one or both directions is housed in a pouch case 114. Such a battery cell 110 may be in the form of a rectangular sheet. The battery cell 110 may be formed by housing an electrode assembly in a pouch case 114 made of a laminate sheet including a resin layer and a metal layer, and then bonding the outer periphery of the pouch case 114. As an example, the battery cell 110 may have a structure in which two electrode leads 111 face each other and protrude from one end 114a and the other end 114b of the cell body 113, respectively. As another example, the electrode leads 111 of the battery cell 110 may all protrude in one direction. One of the electrode leads 111 is a positive electrode lead, and the other is a negative electrode lead.

[0039] The battery cell 110 can be manufactured by bonding both ends 114a, 114b of the pouch case 114 and one side 114c connecting them together while an electrode assembly (not shown) is housed in the pouch case 114. That is, the battery cell 110 according to one embodiment of the present invention has a total of three sealing portions corresponding to both ends 114a, 114b and one side 114c, and the sealing portions can be sealed by a method such as fusion welding, and the remaining other portion can be formed as a folding portion 115. That is, the battery cell 110 according to this embodiment can be a pouch-type secondary battery in which an electrode assembly is housed inside the pouch case 114 and the outer periphery of the pouch case 114 is sealed to form a sealing portion.

[0040] The laminate sheet pouch case 114 may include an inner resin layer for sealing, a metal layer for preventing penetration of substances, and an outermost resin layer. Based on the electrode assembly inside the pouch case 114, the inner resin layer may be located innermost, the outer resin layer may be located outermost, and the metal layer may be located between the inner and outer resin layers.

[0041] The outer resin layer protects the electrode assembly from the outside and may have excellent tensile strength and resistance to corrosion relative to its thickness, as well as electrical insulation. This outer resin layer may include polyethylene terephthalate (PET) resin or nylon resin. The metal layer may prevent air, moisture, etc. from entering the pouch-type secondary battery. This metal layer may include aluminum (Al). The inner resin layer may be heat-sealed by applying heat and / or pressure with the electrode assembly inside. This inner resin layer may include cast polypropylene (CPP) or polypropylene (PP).

[0042] The pouch case 114 may be divided into two sections, and at least one of the two sections may have a recessed storage section in which an electrode assembly can be placed. The inner resin layers of the two sections of the pouch case 114 may be joined together along the outer periphery of the storage section to form a sealing section. The pouch case is sealed in this manner, and the battery cell 110, which is a pouch-type secondary battery, can be manufactured.

[0043] Within the battery cell stack 110A, the battery cell 110 may be composed of multiple battery cells. The multiple battery cells 110 may be stacked so as to be electrically connected to each other. In particular, the multiple battery cells 110 may be stacked in an upright state in a direction parallel to the x-axis. This allows the electrode leads 111 to protrude in a direction perpendicular to the stacking direction of the battery cells 110. In the battery cell 110, one electrode lead 111 may protrude in the y-axis direction, and the other electrode lead 111 may protrude in the -y-axis direction. In the case of a battery cell in which the electrode leads 111 protrude in only one direction, the electrode leads 111 may protrude in the x-axis direction or the -x-axis direction.

[0044] 4 is a perspective view showing a battery cell stack included in the battery assembly of FIG. 2 and including the battery cell of FIG. 3, and FIG. 5 is an exploded perspective view of a battery cell unit included in the battery cell stack of FIG.

[0045] 4 and 5 , in the battery cell stack 110A according to this embodiment, the battery cells 110 may be stacked to form a battery cell unit 110U. Specifically, the battery assembly 100 according to this embodiment may include a plurality of battery cell units 110U, and each battery cell unit 110U may include at least one battery cell 110 and a cell cover 200 that partially covers the at least one battery cell 110.

[0046] That is, according to this embodiment, one or more battery cells 110 are arranged inside the cell cover 200 to form a battery cell unit 110U, and such battery cell units 110U can be stacked in one direction to form a battery cell stack 110A.

[0047] Within the battery cell unit 110U, the battery cell 110 may be composed of one or more battery cells. As an example, FIG. 4 shows the battery cell unit 110U including three battery cells 110. The multiple battery cells 110 may be stacked so as to be electrically connected to each other. In particular, within the battery cell unit 110U, the multiple battery cells 110 may be stacked along a direction parallel to the x-axis in an upright state with one surface of the cell body 113 facing each other.

[0048] 6(a) is a perspective view of the cell cover of FIG. 5 seen from another angle, and FIG. 6(b) is a cross-sectional view showing a cross section cut along the cutting line AA' of FIG. 5.

[0049] 6(a) and 6(b), the cell cover 200 according to this embodiment may include a side portion 210 that covers one side of the battery cell 110. The cell cover 200 may also include a bottom portion 220 that connects the side portion 210 and covers the bottom of at least one battery cell 110.

[0050] The cell cover 200 may include two side portions 210 and one bottom portion 220. One side of the side portion 210 and one side of the bottom portion 220 may be perpendicular, and the side portions 210 may extend upward from opposite sides of the bottom portion 220. The cell cover 200 according to this embodiment may have an open top. That is, when the cell cover 200 in FIG. 5 is cut along the xz plane, the cell cover 200 may have a "U" shape. The cell cover 200 may be provided to cover at least a portion of three of the remaining four sides of the six battery cell 110, excluding the two sides on which the electrode leads 111 are formed. In this embodiment, the cell cover 200 is provided to cover three sides excluding the two sides on which the electrode leads 111 are formed and the top surface of the battery cell 110, i.e., the surface in the +Z direction of the Z axis direction.

[0051] Corresponding to the two surfaces on which the electrode leads 111 are formed, openings 201 defined by two side surfaces 210 and one bottom surface 220 are formed on both sides. That is, the openings 201 are formed on both ends in the Y-axis direction as viewed in the drawing. The electrode leads 111 can be exposed in the openings 201.

[0052] A foam layer 120 is formed adjacent to the electrode lead 111 and between the side surface portion 210 and the battery cell 110. As will be described later, the foam layer 120 expands during thermal runaway to block the open portion 201, thereby enabling venting gas and the like to be guided in a specific direction. The foam layer 120 will be described later.

[0053] Meanwhile, as described above, the battery cells 110 are positioned between the side portions 210 of the cell cover 200, so that the battery cells 110 in the battery cell stack 110A can be divided into battery cell units 110U. By dividing the battery cells 110 in the battery cell stack 110A into battery cell units 110U using the cell covers 200, the propagation of a thermal event or thermal runaway can be delayed. Even if a thermal event or thermal runaway occurs in one of the battery cells 110, the side portions 210 of the cell cover 200 are located in the direction in which the battery cells 110 are stacked, so that the propagation of the thermal event or thermal runaway to the battery cells 110 of adjacent battery cell units 110U is blocked.

[0054] The cell cover 200 can not only delay thermal runaway but also complement the rigidity of the battery cells 110, thereby enabling the battery cells 110 to maintain an upright state. The cell cover 200 can support the battery cells 110 by covering at least a portion of the battery cells 110, and can stably maintain the stacked state of the battery cells 110 arranged upright in one direction. More specifically, the side portion 210 of the cell cover 200 supports the side of the battery cells 110, thereby enabling the battery cells 110 to maintain an upright state.

[0055] The cell cover 200 may be made of a material that has a high melting point so as not to melt even in the event of thermal runaway and that can block the propagation of thermal events and thermal runaway. In addition, the cell cover 200 may be made of a material that has a mechanical strength above a predetermined range so as to stably support the battery cell 110, thereby protecting the battery cell 110 from external impacts, etc. There are no particular limitations on the material used for the cell cover 200, and examples include at least one of mica, steel, aluminum, and plastic.

[0056] Pads 400 may be interposed between the battery cell units 110U, i.e., between the cell covers 200. Pads 400 may also be interposed on the outer surface of the cell cover 200 of the outermost battery cell unit 110U. Such pads 400 may function as a thermal barrier that can block the propagation of thermal events or thermal runaway. In other words, there are no particular limitations on the material of the pad 400 according to this embodiment, as long as it can exhibit a predetermined thermal insulation performance. For example, the pad 400 may include a silicon (Si) material or an aerogel material.

[0057] Meanwhile, according to this embodiment, a cell cover venting hole 220H may be formed in the lower surface portion 220 of the cell cover 200. If a thermal event occurs in one of the battery cells 110 and high-temperature gas, particles, or flames are generated, as described above, the side surface portion 210 of the cell cover 200 can prevent the high-temperature gas, particles, or flames from spreading to an adjacent battery cell 110. The high-temperature gas, particles, or flames can be exhausted through the cell cover venting hole 220H formed in the lower surface portion 220. The cell cover venting hole 220H may be connected to the venting hole 300VH provided on the lower surface of the battery assembly 100.

[0058] At this time, high-temperature gas, particles, or flames are discharged through the cell cover venting holes 220H, but as described above, because the cell cover 200 includes the opening 201 exposing the electrode lead 111, the high-temperature gas, particles, or flames may be discharged not only through the cell cover venting holes 220H but also through the opening 201 exposing the electrode lead 111. However, in one embodiment of the present invention, by including the foam layer 120 disposed adjacent to the electrode lead 111 as described above, this possibility is prevented, and the high-temperature gas, particles, or flames can be discharged only in the intended direction, i.e., through the cell cover venting holes 220H.

[0059] For this reason, the foam layer 120 may be formed of a foamable material whose volume can expand at high temperatures. For example, a silicon-based material or a graphite-based material may be used, and a thermally expandable silicon foam member may be preferably used. The foam layer 120 may be formed by coating the periphery of the electrode lead 111 with the material or by attaching a tape made of a foamable material, but is not particularly limited thereto.

[0060] The foam layer 120 expands in volume in a high-temperature environment, filling the gap between the electrode lead 111 and the side surface 210 of the cell cover 200 and closing the opening 201. Therefore, when thermal runaway occurs, the venting gas is prevented from venting toward the electrode lead 111, and can be guided to vent in the intended direction, i.e., toward the cell cover venting hole 220H.

[0061] Meanwhile, the battery cell stack 110A may be housed in a storage frame 300 or may form a battery assembly 100 by itself. That is, a plurality of battery cell stacks 110A may be provided to directly form a battery pack 1000, or a plurality of battery cell stacks 110A may be housed in a storage frame 300 to form a battery pack 1000. If the storage frame 300 is omitted and the battery cell stack 110A directly forms the battery pack 1000, the number of components is reduced, thereby reducing costs and weight and increasing energy density. When the battery pack 1000 is constructed after being housed in the storage frame 300, disassembly and reassembly are advantageous. Hereinafter, a case in which the battery pack 1000 is constructed by housing the battery cell stack 110A in the storage frame 300 will be described as an example, but is not limited thereto. Referring to FIGS. 1 and 2, the storage frame 300 may include an upper frame 310 and a lower frame 320, and the battery cell stack 110A may be housed in an internal space formed by the upper frame 310 and the lower frame 320. A venting hole 300VH is formed on the underside of the battery assembly 100, which is connected to the cell cover venting hole 220H of the cell cover 200. Specifically, the venting hole 300VH may be formed on the underside of the lower frame 320. The venting hole 300VH communicates with a venting channel formed in a pack housing of the battery pack, which will be described later, to allow high-temperature gas, particles, or flames caused by a thermal event occurring in a particular battery cell 110 to be exhausted to the outside. This will be described in more detail later.

[0062] In addition, the lower surface, i.e., the inner surface, of the upper frame 310 faces the upper end of the cell cover 200. The upper end of the cell cover 200 is open, exposing the upper portions of the battery cells 110. A first thermally conductive resin layer 610 (shown in FIG. 9 ) may be formed at the upper end of the cell cover 200 between the upper portions of the battery cells 110 and the lower surface of the upper frame 310. The first thermally conductive resin layer 610 is formed to contact the upper end of the side portion 210 of the cell cover 200 and to cover the open upper end of the cell cover 200. This allows the battery cell unit 110U to be fixed, cools heat generated inside the battery cell unit 110U, and prevents venting gas from being discharged to the upper end when a thermal event occurs.

[0063] In the battery cell stack 110A, a bus bar frame 500 is disposed on one or both surfaces in the direction in which the electrode leads 111 protrude. As an example, in the battery cell 110 according to this embodiment, the electrode leads 111 can protrude in both directions, i.e., the y-axis direction and the -y-axis direction. This allows the bus bar frame 500 to be disposed on both surfaces of the battery cell stack 110A in the y-axis direction and the -y-axis direction.

[0064] A bus bar 510 and a terminal bus bar 520 may be attached to the bus bar frame 500 on a surface opposite to the surface facing the battery cell stack 110A. The electrode lead 111 may pass through a slit formed in the bus bar frame 500, bend, and be connected to the bus bar 510 or the terminal bus bar 520. The manner in which the electrode lead 111 is connected to the bus bar 510 or the terminal bus bar 520 is not particularly limited as long as an electrical connection is possible, and may be, for example, by welding. The battery cells 110 in the battery cell stack 110A may be electrically connected using the bus bar 510. Meanwhile, as shown in FIG. 1 , a portion of the terminal bus bar 520 is exposed to the outside of the storage frame 300. The battery assembly 100 forms an HV connection with other battery assemblies and electrical components through the terminal bus bar 520.

[0065] On the other hand, according to this embodiment, even if a thermal event occurs in some of the battery cells 110, the opening 201 of the cell cover 200 in which the electrode lead 111 is formed is blocked by the expansion of the foam layer 120, thereby preventing high-temperature gas, particles, or flames generated by the thermal event from being discharged outside the electrode lead 111, and therefore preventing damage to the bus bar frame 500 and various components included therein located on the outside in that direction.

[0066] As described above, according to one embodiment of the present invention, the foam layer 120 disposed adjacent to the electrode lead 111 expands at high temperatures to prevent high-temperature gas, particles, or flames from being discharged into the opening 201 of the cell cover 200, and venting can be controlled to occur only in the intended direction (cell cover venting hole 220H of the lower surface 220), thereby improving safety through control of venting gas.

[0067] Hereinafter, a battery assembly according to another embodiment of the present invention will be described with reference to FIG.

[0068] FIG. 7 is an exploded perspective view of a battery cell unit included in a battery assembly according to another embodiment of the present invention.

[0069] Referring to FIG. 7, a battery assembly according to another embodiment of the present invention is the same as the above-described embodiment except that it further includes an anti-blocking bump 130, and therefore only this will be described.

[0070] 7, an anti-clogging bump 130 may be provided adjacent to one of the cell cover venting holes 220H adjacent to the electrode lead 111. When the foam layer 120 expands in volume at high temperatures, the anti-clogging bump 130 prevents the expanded foam layer 120 material from flowing into the cell cover venting hole 220H and clogging the cell cover venting hole 220H. Thus, the anti-clogging bump 130 may be disposed between the cell cover venting hole 220H and the foam layer 120. The anti-clogging bump 130 may be made of a material with excellent heat resistance. For example, the anti-clogging bump 130 may be formed by attaching a pad made of a heat-resistant resin or a pad made of the same material as the cell cover 200, but is not particularly limited thereto.

[0071] By further including the anti-clogging bump 130, unnecessary portions, i.e., the cell cover venting holes 220H, are prevented from being blocked by the expansion of the foam layer 120, and only the open portion 201 of the cell cover 200 is blocked, thereby more effectively directing the venting gas in the intended direction.

[0072] Hereinafter, a battery pack according to another embodiment of the present invention will be described with reference to FIGS.

[0073] FIG. 8 is an exploded perspective view showing a battery pack according to still another embodiment of the present invention, and FIG. 9 is a cross-sectional view showing a cross section taken along line BB' in FIG.

[0074] 8 and 9, a battery pack 1000 according to an embodiment of the present invention includes at least one battery assembly 100 as described above, and a pack housing 1100 that houses the at least one battery assembly 100. A plurality of venting channels (VC) connected in one direction are formed inside the pack housing 1100, and the venting channels (VC) communicate with the venting holes 300VH of the battery assemblies 100 described above. Each of the venting channels (VC) has an independent venting flow path that is not shared with another.

[0075] When a thermal event occurs in a specific battery cell 110 and high-temperature gas, particles, or flames are emitted from the battery cell 110, the gas, particles, or flames flow from the battery cell 110 into the venting channels (VC). Here, the particles may be metal particles. The venting channels (VC) do not share space with each other and may have independent venting paths. As a result, high-temperature gas, particles, or flames passing through one venting channel (VC) are not propagated to other adjacent venting channels (VC), thereby minimizing the propagation of a thermal event generated in a specific battery cell 110 to other battery cells 110.

[0076] The pack housing 1100 includes a bottom frame 1150 on which the battery assemblies 100 are placed, and a plurality of venting channels (VC) may be formed inside the bottom frame 1150. The bottom frame 1150 also has an opening 1151P formed therein, which can guide high-temperature gas, particles, or flames generated during a thermal event in the battery cells 110 into the venting channel (VC). Specifically, the venting hole 300VH formed in the lower frame 320 of the storage frame 300 can communicate with the venting channel (VC) through the opening 1151P of the bottom frame 1150. In addition, in the battery cell unit 110U according to this embodiment, the cell cover venting hole 220H formed in the cell cover 200 can communicate with the venting hole 300VH. That is, the venting hole 300VH may be positioned corresponding to the opening 1151P, and the cell cover venting hole 220H may be positioned corresponding to the venting hole 300VH.

[0077] As a result, when a thermal event occurs in a specific battery cell 110 and high-temperature gas, particles, or flames are emitted from the battery cell 110, the gas, particles, or flames can flow into the venting channel (VC) inside the bottom frame 1150 of the pack housing 1100 through the cell cover venting hole 220H, the venting hole 300VH, and the opening 1151P. The gas, particles, or flames that flow into the venting channel (VC) are discharged to the outside of the battery pack 1000. The battery pack 1000 according to this embodiment has a "bottom venting" structure that discharges high-temperature gas, particles, or flames generated inside the battery assembly 100 to the outside using the bottom frame 1150 of the pack housing 1100. As described above, a high-voltage current path exists in the upper region of the battery assembly 100, such as the HV (High Voltage) connection of the terminal bus bar. Here, the HV connection refers to a connection between battery cells or between battery assemblies, which functions as a power source for supplying power requiring high voltage. If high-temperature gases or particles caused by a thermal event in a battery cell come into contact with a high-voltage path such as an HV connection, a short circuit or arc discharge may occur, which may lead to an additional explosion or fire. Meanwhile, the battery pack according to this embodiment has a "bottom venting" structure, as described above, so that high-temperature gases or particles caused by a thermal event are discharged downward, i.e., to the bottom frame 1150 of the pack housing 1100. Therefore, there is no risk of high-temperature gases or particles coming into contact with a high-voltage path such as an HV connection, ultimately improving safety against thermal runaway.

[0078] Meanwhile, in the battery assembly 100 according to an embodiment of the present invention, the battery cell 110 may be arranged such that the folding portion 115 of the battery cell 110 faces upward and one side 114c of the battery cell 110 faces downward. That is, the battery cell 110 may be arranged such that the folding portion 115 of the battery cell 110 faces upward and the sealing portion of one side 114c of the battery cell 110 faces downward.

[0079] The lower end of the battery cell 110 may be a sealing portion where the pouch case 114 is sealed, and the upper end of the battery cell 110 may be a folding portion 115 where the pouch case 114 is folded rather than a sealing portion. As a result, the battery cell 110 can be positioned so that the sealing portion of the battery cell 110 faces the venting channel (VC) inside the pack housing 1100. Also, the sealing portion of the battery cell 110 can be positioned to face the cell cover venting hole 220H of the cell cover 200. Referring to FIG. 4, the battery cell 110 has a sealing portion on one side 114c, and can be positioned in the battery assembly 100 so that the sealing portion of the one side 114c faces downward and the folding portion 115 of the battery cell 110 faces upward.

[0080] When a thermal event or thermal runaway occurs in the battery cell 110, venting gas is generated in the battery cell 110, increasing the internal pressure of the battery cell 110. This venting gas can be discharged mainly through the sealing portion of the battery cell 110. That is, the increased internal pressure causes a portion of the sealing portion to become unsealed, and the venting gas can be discharged through the unsealed portion of the sealing portion.

[0081] In the battery assembly 100 according to this embodiment, the battery cells 110 may be arranged so that their lower ends form the sealing portion and their upper ends form the folding portion 115. This arrangement more clearly achieves a "bottom venting" structure that discharges venting gas and particles generated from the battery cells 110 downward. Each venting channel (VC) has an independent venting flow path that is not shared with other venting channels. Therefore, gas, particles, or flames may flow into any one venting channel (VC) connected to a battery cell 110 in which a thermal event has occurred, but the gas, particles, or flames do not propagate to other adjacent venting channels (VC). Therefore, gas, particles, or flames do not flow into other battery cells 110 connected to other venting channels (VC), and ultimately, the thermal event does not propagate or trigger to other battery cells 110.

[0082] In particular, each venting channel (VC) may be positioned to correspond to each battery cell unit 110U. Each venting channel (VC) may be in one-to-one communication with each battery cell unit 110U. That is, the number of venting channels (VC) may match the number of battery cell units 110U in the battery cell stack 110A, and any one battery cell unit 110U may be in communication only with the venting channel (VC) located above it, and not with the other venting channels (VC).

[0083] High-temperature gases and flames generated in any battery cell unit 110U are exhausted only to the venting channel (VC) connected to it, and movement to other venting channels (VC) is restricted. As described above, in the battery cell stack 110A according to this embodiment, the battery cells 110 are housed in the cell cover 200 to form the battery cell unit 110U. High-temperature gases and flames generated by thermal runaway in any battery cell unit 110U are blocked by the side surface 210 of the cell cover 200 and cannot propagate to adjacent battery cell units 110U. In addition, the expansion of the foam layer 120 also blocks the opening 201 of the cell cover 200, preventing the gases and flames from escaping in the direction of the electrode leads 111.

[0084] When high-temperature gas or flame is discharged from the top of a battery cell unit 110U into a corresponding venting channel (VC), the venting channels (VC) each have an independent venting flow path that is not shared with each other, preventing the high-temperature gas or flame from flowing into adjacent venting channels (VC). Therefore, there is no risk of high-temperature gas or flame backflowing into adjacent venting channels (VC) and other battery cell units 110U located above them. If the venting flow paths of the venting channels (VC) were shared with each other, there would be a risk of high-temperature gas or flame flowing into a battery cell unit 110U in which thermal runaway is not occurring, because the internal pressure is relatively lower than that of a battery cell unit 110U in which thermal runaway is occurring. In this embodiment, by providing a separate venting path for each battery cell unit 110U, thermal runaway transition between battery cells 110 is minimized, preventing structural collapse of the battery pack.

[0085] In the battery pack 1000 according to this embodiment, the number of battery cells 110 may be greater than the number of venting channels (VC). A battery cell unit 110U may include a plurality of battery cells 110 and a cell cover that partially covers the battery cells 110. The plurality of battery cells 110 in the battery cell unit 110U may be covered with a cell cover 200. Each of the venting channels (VC) may be located to correspond to each of the battery cell units 110U. One venting channel (VC) may correspond to a plurality of battery cells 110 in the battery cell unit 110U. Therefore, the number of battery cells 110 may be greater than the number of venting channels (VC).

[0086] If the number of battery cells 110 and the number of venting channels (VC) were set to be the same and one venting channel (VC) were set to correspond to each individual battery cell 110, multiple independent venting channels (VC) would be required, which would be structurally complex and inefficient. Therefore, in this embodiment, multiple battery cells 110 are bundled together to form battery cell units 110U, and each venting channel (VC) is provided to correspond to each of these battery cell units 110U, thereby efficiently realizing independent venting channels (VC).

[0087] Meanwhile, the pack housing 1100 according to an embodiment of the present invention may be a housing with an open top. The pack housing 1100 may include a bottom frame 1150 on which the battery assembly 100 is placed, and side portions 1110, 1120, 1130, and 1140 connected along the edge of the bottom frame 1150. For example, the pack housing 1100 may include a first side portion 1110, a second side portion 1120, a third side portion 1130, and a fourth side portion 1140, and the bottom frame 1150. The first to fourth side portions 1110, 1120, 1130, and 1140 may be arranged along the four sides of the rectangular bottom frame 1150. The battery assembly 100 may be fitted in an internal space formed by the bottom frame 1150 and the first to fourth side portions 1110, 1120, 1130, and 1140.

[0088] In addition, a pack cover 1200 may cover the open top of the pack housing 1100. Although not specifically shown, gaskets may be interposed between the first to fourth side portions 1110, 1120, 1130, and 1140 of the pack housing 1100 and the pack cover to improve sealing performance.

[0089] A second thermally conductive resin layer 620 may be further disposed between the pack cover 1200 and the battery assembly 100. That is, as shown in FIG. 9, a second thermally conductive resin layer 620 may be further formed on the upper portion of the battery assembly 100 exposed to the open top of the pack housing 1100. The second thermally conductive resin layer 620 is formed in succession in contact with the upper surface of the storage frame 300 of the battery assembly 100 and the first thermally conductive resin layer 610 formed on the inner surface of the upper surface, thereby effectively cooling and dissipating heat generated inside the battery assembly 100 to the outside. A cooling member (not shown) may also be further included on the upper portion of the battery assembly 100 for additional cooling. To achieve a "bottom venting" structure in which high-temperature gases, particles, or flames generated inside the battery assembly 100 are discharged to the outside using the bottom frame 1150 of the pack housing 1100, the cooling member may be located at the top rather than the bottom of the battery assembly 100. The cooling member is not particularly limited in its form or method as long as it can cool the heat generated from the battery assembly 100. For example, the cooling member may be a heat sink with a circulating coolant flowing inside. At the same time, the cooling device is not limited thereto and may be applied in various forms.

[0090] The bottom frame 1150 according to this embodiment may include a venting plate 1151 on which the battery assembly 100 is placed and a lower plate 1152 located below the venting plate 1151. A venting unit 1300 may be located between the venting plate 1151 and the lower plate 1152, and the above-mentioned venting channel (VC) may be formed in the venting unit 1300.

[0091] In a "bottom venting" battery pack structure, the space between the venting plate 1151 and the bottom plate 1152 is used as a space through which gas or flame flows, i.e., a venting channel (VC) is formed. The venting unit 1300 can realize this space as a venting channel (VC) that is an independent venting flow path that is not shared with other venting channels. The openings 1151P described above can be formed in the venting plate 1151 of the bottom frame 1150. That is, the venting plate 1151 can include openings 1151P formed in portions corresponding to the venting holes 300VH of the battery assembly 100, and the venting holes 300VH can communicate with the venting channel (VC) through the openings 1151P. The openings 1151P can be formed by opening at least a portion of the area of ​​the venting plate 1151 corresponding to the venting channel (VC). There are no particular limitations on the number or area of ​​the openings 1151P. A flange portion 300F provided on the outer periphery of the venting hole 300VH can be inserted into the venting flow path of the venting channel (VC) while passing through the opening 1151P of the bottom frame 1150.

[0092] As described above, according to the embodiments of the present invention, even if a thermal event occurs in some cells and high-temperature gas, flames, and particles are generated, the gas can be discharged in the intended direction and to the outside through the flow paths formed in the battery pack. In particular, during this process, the cell cover prevents the high-temperature gas from being transmitted to adjacent battery cell units, and the opening of the cell cover is also blocked by the expansion of the foam layer, so gas venting can be controlled more effectively, thereby improving the safety of the battery assembly and battery pack.

[0093] In this embodiment, terms indicating directions such as front, back, left, right, up, and down are used, but these terms are used only for convenience of explanation and may change depending on the position of the object of interest, the position of the observer, etc.

[0094] The battery assembly or battery pack can be applied to various devices, specifically, but not limited to, transportation means such as electric bicycles, electric cars, and hybrids, and ESS (Energy Storage Systems), and can be applied to various devices that can use secondary batteries.

[0095] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art by utilizing the basic concept of the present invention defined in the claims below also fall within the scope of the present invention. [Explanation of symbols]

[0096] 100 Battery Assembly 110 battery cells 110U battery cell unit 110A battery cell stack 120 foam layer 130 Anti-occlusion bump 200 cell covers 300 Storage Frame 400 pads 1000 battery packs

Claims

1. 1. A battery assembly comprising: a plurality of battery cell units, each including at least one battery cell and a cell cover covering a bottom surface and both side surfaces of the at least one battery cell; the cell cover includes at least one cell cover vent hole in a lower surface portion corresponding to a lower surface of the at least one battery cell; Electrode leads protrude from both end surfaces of the at least one battery cell in the longitudinal direction, a foam layer disposed adjacent to at least one electrode lead of the at least one battery cell.

2. the cell cover includes openings on both sides that expose the electrode leads; The battery assembly according to claim 1 , wherein the foam layer expands in volume at high temperatures to close the openings on both sides.

3. The battery assembly according to claim 1 , further comprising a first thermally conductive resin layer disposed on the at least one battery cell.

4. the cell cover includes side surfaces extending vertically from the bottom surface portion and corresponding to the two side surfaces of the at least one battery cell; The battery assembly according to claim 3 , wherein the upper end of the side surface portion is in contact with the first thermally conductive resin layer.

5. The battery assembly according to claim 1 , further comprising an anti-blocking bump disposed adjacent to the cell cover venting hole adjacent to the electrode lead among the at least one cell cover venting hole.

6. further comprising a storage frame that stores the plurality of battery cell units; The battery assembly according to claim 1 , wherein the receiving frame includes at least one vent hole formed on a lower surface of the receiving frame at a position corresponding to the at least one cell cover vent hole.

7. The battery assembly according to any one of claims 1 to 6; and A battery pack including a pack housing that houses the battery assembly.

8. The battery pack according to claim 7 , further comprising a plurality of venting channels communicating with the at least one cell cover venting hole and extending from the interior of the bottom frame of the pack housing.

9. The battery pack according to claim 8 , wherein each of the venting channels is in communication with each of the battery cell units in a one-to-one relationship.

10. the battery assembly further includes a receiving frame that receives the plurality of battery cell units and includes at least one vent hole formed at a position corresponding to the at least one cell cover vent hole; The battery pack according to claim 8 , wherein the venting channel communicates with the venting hole.

11. the battery assembly further includes a first thermally conductive resin layer disposed between an upper portion of the at least one battery cell and an upper surface of the storage frame; The battery pack of claim 10 , further comprising a pack cover disposed outside the storage frame and coupled to an upper portion of the pack housing.

12. The battery pack according to claim 11 , further comprising a second thermally conductive resin layer disposed between the pack cover and the upper surface of the housing frame.

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