Battery assembly and device including the same

Abstract

A battery assembly according to one embodiment of the present invention comprises a plurality of battery cell units, each comprising at least one battery cell and a cell cover covering the bottom surface and both sides of the at least one battery cell, wherein the cell cover includes at least one cell cover venting hole in the bottom surface corresponding to the bottom surface of the battery cell, electrode leads protrude from both ends in the longitudinal direction of the battery cell, and includes a foam layer disposed adjacent to the electrode leads of at least one of the at least one battery cell.

Description

Technology Field

[0001] The present invention relates to a battery assembly and a battery pack including the same, and more specifically, 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

[0002] In modern society, as the use of portable devices such as mobile phones, laptops, camcorders, and digital cameras has become commonplace, the development of technologies related to such mobile devices is becoming active. Furthermore, rechargeable secondary batteries are being utilized as power sources 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 vehicles using fossil fuels; consequently, the need for the development of secondary batteries is increasing.

[0003] Currently commercialized rechargeable batteries include nickel-cadmium, nickel-hydrogen, nickel-zinc, and lithium-ion batteries. Among these, lithium-ion batteries are gaining attention for their advantages, such as the ability to charge and discharge freely with almost no memory effect compared to nickel-based batteries, a very low self-discharge rate, and high energy density.

[0004] These lithium secondary batteries primarily use lithium-based oxides and carbon materials as the positive and negative active materials, respectively. The lithium secondary battery comprises an electrode assembly in which a positive plate and a negative plate, each coated with the positive and negative active materials, are arranged with a separator in between, and a battery case that seals and houses the electrode assembly together with an electrolyte.

[0005] Generally, lithium secondary batteries can be classified according to the shape of the casing into can-type secondary batteries, in which the electrode assembly is embedded in a metal can, and pouch-type secondary batteries, in which the electrode assembly is embedded in a pouch of aluminum laminate sheet.

[0006] In the case of secondary batteries used in small devices, 2 to 3 battery cells are arranged, whereas in the case of secondary batteries used in medium to large devices such as automobiles, battery modules in which multiple battery cells are electrically connected are used. In such battery modules, capacity and output are improved by connecting multiple battery cells in series or parallel to form a stack of battery cells. One or more battery modules can be mounted together 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.

[0007] A battery pack includes battery modules as a sub-concept, and battery modules include battery cells as a sub-concept. Furthermore, 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 or capacity of the battery pack required for an electric vehicle.

[0008] However, in the case of such battery packs, one of the most critical issues is safety. In particular, if a thermal event occurs in any one of the multiple battery cells included in the pack, it is necessary to prevent the propagation of such thermal event to other battery cells and modules.

[0009] If thermal propagation between battery cells and modules is not properly suppressed, it can lead to thermal events in other battery cells within the battery pack, potentially causing more serious problems such as ignition or explosion of the battery pack. Furthermore, ignition or explosion occurring within the battery pack can cause significant damage to surrounding human lives and property. Therefore, such battery packs require a configuration capable of appropriately controlling the aforementioned thermal events and their propagation. The problem to be solved

[0010] The problem that the present invention aims to solve is to provide a battery assembly and a battery pack including the same, which can prevent a thermal event from propagating to adjacent battery cells and battery assemblies by venting a venting gas, particle, or flame, etc., only in a specific intended direction so that it moves along a predetermined path and is discharged to the outside when a thermal event occurs in a specific battery cell.

[0011] However, the problems that the embodiments of the present invention aim to solve are not limited to the problems described above and can be expanded in various ways within the scope of the technical ideas included in the present invention. means of solving the problem

[0012] A battery assembly according to one embodiment of the present invention comprises a plurality of battery cell units, each comprising at least one battery cell and a cell cover covering the bottom surface and both sides of the at least one battery cell, wherein the cell cover includes at least one cell cover venting hole in the bottom surface corresponding to the bottom surface of the battery cell, electrode leads protrude from both ends in the longitudinal direction of the battery cell, and a foam layer disposed adjacent to the electrode leads of at least one of the at least one battery cell.

[0013] The cell cover includes two open portions that expose the electrode leads, and the foam layer can block the two open portions by expanding in volume at high temperature.

[0014] The above battery assembly may further include a first thermally conductive resin layer disposed on the upper part of the battery cell.

[0015] The cell cover above includes a side portion that extends vertically from the lower surface and corresponds to both sides of the battery cell, and the upper end of the side portion can be in contact with the first thermally conductive resin layer.

[0016] The battery assembly may further include a blockage prevention ridge disposed adjacent to the cell cover venting hole adjacent to the electrode lead among the at least one cell cover venting hole.

[0017] The battery assembly further includes a storage frame for accommodating the plurality of battery cell units, and the storage frame may include at least one venting hole formed at a position corresponding to the cell cover venting hole on the lower surface of the storage frame.

[0018] A battery pack according to one embodiment of the present invention includes the battery assembly and a pack housing that accommodates the battery assembly.

[0019] The battery pack may further include a plurality of venting channels that communicate with the cell cover venting hole and extend from the inside of the bottom frame of the pack housing.

[0020] Each of the above venting channels can be connected one-to-one with each of the above battery cell units.

[0021] The battery assembly further includes a storage frame that accommodates 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 can communicate with the venting hole.

[0022] The battery assembly further includes a first thermally conductive resin layer disposed between the upper portion of the battery cell and the upper surface of the storage frame, and the battery pack may further include a pack cover disposed on the outside of the storage frame and coupled to the upper portion of the pack housing.

[0023] 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

[0024] According to embodiments of the present invention, when a thermal event occurs in a specific battery cell, venting gas, particles, or flames, etc., are vented only in a specific intended direction so that they travel along a predetermined path and are discharged to the outside, thereby minimizing the propagation of the said thermoelectric event to adjacent other battery cells and battery assemblies.

[0025] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims. Brief explanation of the drawing

[0026] FIG. 1 is a perspective view showing a battery assembly according to one embodiment of the present invention. Figure 2 is an exploded perspective view of the battery assembly of Figure 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 that is included in the battery assembly of FIG. 2 and includes 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 viewed from a different angle, and FIG. 6(b) is a cross-sectional view showing a cross section cut along the cutting line A-A' of FIG. 5. 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. FIG. 8 is an exploded perspective view showing a battery pack according to another embodiment of the present invention. Figure 9 is a cross-sectional view showing a cross-section cut along the cutting line B-B' of Figure 8. Specific details for implementing the invention

[0027] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0028] To clearly explain the present invention, parts unrelated to the explanation have been omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0029] Furthermore, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and thus the present invention is not necessarily limited to what is illustrated. Thicknesses have been enlarged in the drawings to clearly represent various layers and regions. Additionally, for convenience of explanation, the thickness of some layers and regions has been exaggerated in the drawings.

[0030] Furthermore, when a part such as a layer, membrane, region, or plate is said to be "on" or "on" 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. Also, saying that a part is "on" or "on" a reference part means that it is located above or below the reference part, and does not necessarily mean that it is located "on" or "on" facing the opposite direction of gravity.

[0031] Furthermore, throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0032] Additionally, throughout the specification, "planar" means when the subject part is viewed from above, and "cross-sectional" means when the cross-section obtained by vertically cutting the subject part is viewed from the side.

[0033] Hereinafter, a battery assembly according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

[0034] 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 viewed from a different angle, FIG. 6 (b) is a cross-sectional view showing a cross-section cut along the cutting line A-A' of FIG. 5.

[0035] Referring to FIGS. 1 to 5, the battery cells (110) according to the present embodiment can be stacked along one direction to form a battery cell stack (110A). Below, the battery cells (110) will be described first.

[0036] The battery cell (110) according to the present embodiment may be a battery cell of various shapes, for example, a pouch-type battery cell, a prismatic battery cell, or a cylindrical battery cell. For example, as shown in FIG. 3, the battery cell (110) according to the present embodiment may be a pouch-type battery cell. Although the following description is about a pouch-type battery cell, the battery cell (110) according to the present embodiment is not limited thereto, and various types of battery cells may be applied.

[0037] The battery cell (110) according to the present embodiment may be in the form 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 shape of a rectangular sheet. The battery cell (110) may be formed by housing an electrode assembly in a pouch case (114) of a laminate sheet comprising a resin layer and a metal layer, and then bonding the outer periphery of the pouch case (114). For 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 embodiment, a structure in which all electrode leads (111) of the battery cell (110) protrude in one direction is also possible. One of the electrode leads (111) is a positive electrode lead, and the other is a negative electrode lead.

[0038] A battery cell (110) can be manufactured by bonding the two ends (114a, 114b) of a pouch case (114) and the one side (114c) connecting them, while the electrode assembly (not shown) is housed in the pouch case (114). In other words, a battery cell (110) according to one embodiment of the present invention has a total of three sealing portions corresponding to the two ends (114a, 114b) and the one side (114c), and the sealing portions are structured to be sealed by a method such as fusion, and the other one side may be formed as a folding portion (115). That is, the battery cell (110) according to the present embodiment may be a pouch-type secondary battery in which the 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.

[0039] The pouch case (114) of the laminate sheet may include an inner resin layer for sealing, a metal layer for preventing penetration of material, and an outermost resin layer. Based on the electrode assembly inside the pouch case (114), the inner resin layer may be located at the innermost position, the outer resin layer at the outermost position, and the metal layer may be located between the inner resin layer and the outer resin layer.

[0040] The outer resin layer may possess excellent tensile strength and weather resistance relative to its thickness and electrical insulation properties to protect the electrode assembly from the outside. This outer resin layer may include polyethylene terephthalate (PET) resin or nylon resin. The metal layer may prevent air, moisture, etc. from entering the interior of the pouch-type secondary battery. This metal layer may include aluminum (Al). The inner resin layers may be thermally fused together by applied heat and / or pressure while the electrode assembly is embedded. This inner resin layer may include casted polypropylene (CPP) or polypropylene (PP).

[0041] A pouch case (114) may be divided into two parts, and a concave-shaped storage portion may be formed in at least one of the two parts so that an electrode assembly can be seated thereon. Along the outer circumference of this storage portion, the inner resin layers of the two parts of the pouch case (114) may be bonded together to form a sealing portion. In this way, the pouch case is sealed so that a battery cell (110), which is a pouch-type secondary battery, can be manufactured.

[0042] In a battery cell stack (110A), the battery cells (110) may be composed of multiple cells. Multiple battery cells (110) may be stacked so as to be electrically connected to each other. In particular, multiple battery cells (110) may be stacked upright along a direction parallel to the x-axis. Accordingly, electrode leads (111) may protrude in a direction perpendicular to the direction in which the battery cells (110) are stacked. In a battery cell (110), one electrode lead (111) may protrude toward the y-axis direction, and another electrode lead (111) may protrude toward the -y-axis direction. If the battery cell has electrode leads (111) protruding in only one direction, the electrode leads (111) may protrude toward the x-axis direction or the -x-axis direction.

[0043] FIG. 4 is a perspective view showing a battery cell stack including the battery cell of FIG. 3, which is included in the battery assembly of FIG. 2, and FIG. 5 is an exploded perspective view of a battery cell unit included in the battery cell stack of FIG. 4.

[0044] Referring to FIGS. 4 and FIGS. 5 together, in a battery cell stack (110A) according to the present embodiment, battery cells (110) may be stacked to form a battery cell unit (110U). Specifically, a battery assembly (100) according to the present embodiment may include a plurality of battery cell units (110U), and a 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).

[0045] That is, according to the present embodiment, a battery cell unit (110U) is formed by arranging one or more battery cells (110) inside a cell cover (200), and a battery cell stack (110A) can be formed by stacking these battery cell units (110U) along one direction.

[0046] In the battery cell unit (110U), the battery cells (110) may be composed of one or more. FIG. 4 illustrates, for example, that the battery cell unit (110U) includes three battery cells (110). Multiple battery cells (110) may be stacked so that they can be electrically connected to one another. In particular, multiple battery cells (110) may be stacked in the battery cell unit (110U) along a direction parallel to the x-axis while standing upright so that one side of the cell body (113) faces each other.

[0047] FIG. 6(a) is a perspective view of the cell cover of FIG. 5 viewed from a different angle, and FIG. 6(b) is a cross-sectional view showing a cross section cut along the cutting line A-A' of FIG. 5.

[0048] Referring to FIG. 6 (a) and (b) together, the cell cover (200) according to the present embodiment may include side portions (210) that cover one side of the battery cell (110). Additionally, the cell cover (200) may include a bottom portion (220) that connects the side portions (210) and covers the bottom of at least one battery cell (110).

[0049] The cell cover (200) may include two side portions (210) and one bottom portion (220). One side of the side portions (210) and one side of the bottom portion (220) may be perpendicular, and the side portions (210) may each extend upward from the opposite sides of the bottom portion (220). The cell cover (200) according to the present embodiment may have an open top side. That is, if 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, excluding the two sides where the electrode leads (111) are formed in the six-sided battery cell (110). In this embodiment, it is provided to wrap three sides excluding the two sides where the electrode lead (111) is formed and the upper surface of the battery cell (110), that is, the side in the +Z direction of the Z-axis direction.

[0050] Corresponding to the two surfaces on which the electrode lead (111) is formed, an opening (201) defined by two side portions (210) and one bottom portion (220) is formed on both sides. That is, an opening (201) is formed at both ends in the Y-axis direction in the drawing. The electrode lead (111) can be exposed through the opening (201).

[0051] Adjacent to the electrode lead (111), a foam layer (120) is formed between the side portion (210) and the battery cell (110). As described later, the foam layer (120) expands during thermal runaway to block the opening (201), thereby allowing venting gas, etc., to be guided in a specific direction. The foam layer (120) will be described in more detail later.

[0052] Meanwhile, as described above, by positioning the battery cells (110) between the side portions (210) of the cell cover (200), the battery cells (110) within the battery cell stack (110A) can be divided into units of battery cell units (110U). By dividing the battery cells (110) within the battery cell stack (110A) into battery cell units (110U) using the cell cover (200), the propagation of a thermal event or thermal runaway can be delayed. Even if a thermal event or thermal runaway occurs in one battery cell (110), the propagation of the thermal event or thermal runaway to the battery cells (110) of an adjacent battery cell unit (110U) is blocked because the side portions (210) of the cell cover (200) are positioned in the direction in which the battery cells (110) are stacked.

[0053] The cell cover (200) can not only delay the thermal runaway phenomenon but also allow the battery cell (110) to maintain an upright state by supplementing the rigidity of the battery cell (110). The cell cover (200) can support the battery cell (110) by covering at least a portion of the battery cell (110) and can stably maintain the stacked state of the battery cells (110) arranged upright in one direction. More specifically, the side portions (210) of the cell cover (200) support the side of the battery cell (110), thereby maintaining the upright state of the battery cell (110).

[0054] The cell cover (200) may be manufactured from a material having a high melting point so as not to melt even during thermal runaway, and capable of blocking the propagation of thermal events or thermal runaway. Additionally, the cell cover (200) may be manufactured from a material having a mechanical strength greater than a predetermined range so as to stably support the battery cell (110), thereby protecting the battery cell (110) from external impacts. There are no special restrictions on the material used for the cell cover (200), but, for example, it may include at least one of mica, steel, aluminum, or plastic.

[0055] A pad (400) may be interposed between the battery cell units (110U), that is, between the cell covers (200). Additionally, a pad (400) may be interposed on the outer surface of the cell cover (200) of the outermost battery cell unit (110U). Such a pad (400) can function as a thermal barrier capable of blocking the propagation of thermal events or thermal runaway. That is, the pad (400) according to the present embodiment has no particular restrictions on its material as long as it can exhibit a certain thermal insulation performance. For example, the pad (400) may include silicon (Si) material or aerogel material.

[0056] Meanwhile, a cell cover venting hole (220H) may be formed on the lower portion (220) of the cell cover (200) according to the present embodiment. When high-temperature gas, particles, or flames are generated due to a thermal event in any one battery cell (110), the side portion (210) of the cell cover (200) can prevent the high-temperature gas, particles, or flames from propagating to an adjacent battery cell (110) as described above. The high-temperature gas, particles, or flames may be discharged through the cell cover venting hole (220H) formed on the lower portion (220). This cell cover venting hole (220H) may be connected to a venting hole (300VH) provided on the lower surface of the battery assembly (100).

[0057] At this time, high-temperature gas, particles, or flames may be discharged through the cell cover venting hole (220H). However, as described above, since the cell cover (200) includes an opening (201) that exposes the electrode lead (111), there is a possibility that high-temperature gas, particles, or flames may be discharged not only through the cell cover venting hole (220H) but also through the opening (201) where the electrode lead (111) is exposed. However, in one embodiment of the present invention, as described above, a foam layer (120) is included that is disposed adjacent to the electrode lead (111), thereby blocking this possibility and making it possible to discharge high-temperature gas, particles, or flames only in the intended direction, that is, through the cell cover venting hole (220H).

[0058] To this end, the foam layer (120) may be formed from a foaming material that can expand in volume at high temperatures. For example, a silicon-based material or a graphite-based material may be used, and a thermally expandable silicone foam member may be preferably used. This foam layer (120) may be obtained by coating the material around the electrode lead (111), or it may be formed by attaching a tape made of the foaming material, and is not particularly limited.

[0059] The foam layer (120) expands in volume in a high-temperature environment, filling the space between the electrode lead (111) and the side portion (210) of the cell cover (200) to block the opening (201). Therefore, in the event of thermal runaway, the venting gas is prevented from venting toward the electrode lead (111) and can be guided to vent toward the intended direction, namely the cell cover venting hole (220H).

[0060] Meanwhile, such a battery cell stack (110A) may be stored in a storage frame (300) or form a battery assembly (100) independently. That is, the battery cell stack (110A) itself may be provided in multiple units to directly form a battery pack (1000), or it may be stored in a storage frame (300) and provided in multiple units to form a battery pack (1000). If the battery cell stack (110A) directly forms a battery pack (1000) without the storage frame (300), the number of parts is reduced, thereby reducing costs and weight, and increasing energy density. If the battery pack (1000) is formed after being stored in a storage frame (300), it may be advantageous for separation and reassembly. In the following description, the case in which the battery pack (1000) is formed by being stored in a storage frame (300) is described as an example, but it is not limited thereto. Referring to FIGS. 1 and 2 together, the storage frame (300) may include an upper frame (310) and a lower frame (320), and a battery cell stack (110A) may be stored in the internal space formed by the upper frame (310) and the lower frame (320). A venting hole (300VH) is formed on the lower surface of the battery assembly (100) and communicates with the cell cover venting hole (220H) of the cell cover (200). Specifically, a venting hole (300VH) may be formed on the lower surface of the lower frame (320). This venting hole (300VH) communicates with a venting channel formed in the pack housing of the battery pack described later, enabling the discharge of high-temperature gas, particles, or flames caused by a thermal event generated in a specific battery cell (110) to the outside. This will be explained in more detail later.

[0061] Additionally, the lower surface of the upper frame (310), i.e., the inner surface, faces the upper portion of the cell cover (200). The upper portion of the cell cover (200) is open, so that the upper portion of the battery cell (110) is exposed. At the upper portion of the cell cover (200), a first thermally conductive resin layer (610, illustrated in FIG. 9) may be formed between the upper portion of the battery cell (110) and the lower surface of the upper frame (310). This first thermally conductive resin layer (610) is formed to be in contact with the upper portion of the side portion (210) of the cell cover (200) and to cover the upper portion of the open cell cover (200). By doing so, the battery cell unit (110U) can be fixed, and at the same time, heat generated inside the battery cell unit (110U) can be cooled, and venting gas can be prevented from being discharged upward in the event of a thermal event.

[0062] In a battery cell stack (110A), a busbar frame (500) may be disposed on one or both sides in the direction in which the electrode leads (111) protrude. For example, in a battery cell (110) according to the present embodiment, the electrode leads (111) may protrude in both directions, namely the y-axis direction and the -y-axis direction. Accordingly, a busbar frame (500) may be disposed on each side in the y-axis direction and the -y-axis direction of the battery cell stack (110A).

[0063] A busbar (510) and a terminal busbar (520) may be mounted on the opposite side of the busbar frame (500) facing the battery cell stack (110A). An electrode lead (111) may be connected to the busbar (510) or the terminal busbar (520) by bending it after passing through a slit formed in the busbar frame (500). The form in which the electrode lead (111) is connected to the busbar (510) or the terminal busbar (520) is not particularly limited as long as an electrical connection is possible, and, for example, a welded joint may be formed. The battery cells (110) within the battery cell stack (110A) may be electrically connected to each other using the busbar (510). Meanwhile, as shown in FIG. 1, a portion of the terminal busbar (520) is exposed to the outside of the storage frame (300). The battery assembly (100) forms an HV connection with another battery assembly or electrical component through this terminal busbar (520).

[0064] Meanwhile, according to the present embodiment, even if a thermal event occurs in some battery cells (110), the opening (201) of the cell cover (200) on which the electrode lead (111) is formed is blocked by the expansion of the foam layer (120), so that high-temperature gas, particles, or flames generated by the thermal event are prevented from being discharged to the outside of the electrode lead (111), and thus damage to the busbar frame (500) and various parts included therein, which are positioned on the outside in that direction, can also be prevented.

[0065] As such, according to one embodiment of the present invention, a foam layer (120) disposed adjacent to an electrode lead (111) can be controlled to prevent high-temperature gas, particles, or flames from being discharged through the opening (201) of the cell cover (200) when it expands at a high temperature, and to allow venting to occur only in an intended direction (cell cover venting hole (220H) of the lower portion (220)), thereby improving safety through the control of the venting gas.

[0066] Hereinafter, a battery assembly according to another embodiment of the present invention will be described with reference to FIG. 7.

[0067] 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.

[0068] Referring to FIG. 7, a battery assembly according to another embodiment of the present invention is identical to the embodiment described above except that it further includes a blockage prevention ridge (130), so only this will be described.

[0069] That is, as illustrated in FIG. 7, a blockage prevention ridge (130) may be included adjacent to the cell cover venting hole (220H) adjacent to the electrode lead (111) among the cell cover venting holes (220H). The blockage prevention ridge (130) serves to prevent the cell cover venting hole (220H) from being blocked by the material of the expanded foam layer (120) flowing into the cell cover venting hole (220H) when the volume of the foam layer (120) expands at a high temperature. To this end, the blockage prevention ridge (130) may be positioned to be interposed between the cell cover venting hole (220H) and the foam layer (120). Additionally, the blockage prevention ridge (130) may be made of a material with excellent heat resistance, for example, by attaching a pad made of a heat-resistant resin or by attaching a pad made of the same material as the cell cover (200), and is not particularly limited.

[0070] By including the blockage prevention ridge (130) in this manner, the unwanted part, namely the cell cover venting hole (220H), is prevented from being blocked by the expansion of the foam layer (120), and only the opening (201) of the cell cover (200) is blocked, thereby allowing the venting gas to be guided more effectively in the intended direction.

[0071] Hereinafter, a battery pack according to another embodiment of the present invention will be described with reference to FIGS. 8 and 9.

[0072] FIG. 8 is an exploded perspective view showing a battery pack according to another embodiment of the present invention, and FIG. 9 is a cross-sectional view showing a cross-section cut along the cutting line B-B' of FIG. 8.

[0073] Referring to FIGS. 8 and 9, a battery pack (1000) according to one embodiment of the present invention comprises at least one battery assembly (100) described above; and a pack housing (1100) that accommodates at least one battery assembly (100). A plurality of venting channels (VCs) extending along one direction are formed inside the pack housing (1100), and the venting channels (VCs) are in communication with the venting holes (300VH) of the battery assembly (100) described above. Each of the venting channels (VCs) has an independent venting path that is not shared with one another.

[0074] When a thermal event occurs in a specific battery cell (110) and high-temperature gas, particles, or flames are ejected from the battery cell (110), the gas, particles, or flames flow from the battery cell (110) into a venting channel (VC). Here, the particles may be metal particles. The venting channels (VCs) may not share space with each other and may have independent venting paths. Accordingly, high-temperature gas, particles, or flames passing through one venting channel (VC) do not propagate to an adjacent venting channel (VC), thereby minimizing the propagation of a thermal event generated in a specific battery cell (110) to other battery cells (110).

[0075] The pack housing (1100) includes a bottom frame (1150) on which the battery assembly (100) is placed, and a plurality of venting channels (VC) may be formed inside the bottom frame (1150). Additionally, an opening (1151P) is formed in the bottom frame (1150) to guide high-temperature gas, particles, or flames generated during a thermal event of the battery cell (110) into the venting channel (VC). Specifically, a venting hole (300VH) formed in the lower frame (320) of the storage frame (300) may be in communication with the venting channel (VC) through the opening (1151P) of the bottom frame (1150). Furthermore, in the battery cell unit (110U) according to the present embodiment, a cell cover venting hole (220H) formed in the cell cover (200) may be in communication with the venting hole (300VH). That is, the venting hole (300VH) can be positioned corresponding to the opening (1151P), and the cell cover venting hole (220H) can also be positioned corresponding to the venting hole (300VH).

[0076] Accordingly, when a thermal event occurs in a specific battery cell (110) and high-temperature gas, particles, or flames are ejected from the battery cell (110), the gas, particles, or flames may flow into the venting channels (VCs) 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 channels (VCs) are discharged to the outside of the battery pack (1000). The battery pack (1000) according to the present 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 busbar. Here, the HV connection is a connection that serves as a power source to supply power requiring high voltage, and refers to a connection between battery cells or between battery assemblies. At this time, if high-temperature gas or particles resulting from a thermal event in the battery cell come into contact with a high-voltage path such as the HV connection, a short circuit or arc discharge may occur, which may lead to additional explosions and flames. On the other hand, in the case of the battery pack according to the present embodiment, as mentioned earlier, it has a "bottom venting" structure, so high-temperature gas or particles resulting from a thermal event are discharged downward, that is, to the bottom frame (1150) of the pack housing (1100). Therefore, there is no risk of high-temperature gas or particles coming into contact with a high-voltage path such as the HV connection, and ultimately, safety against thermal runaway phenomena can be enhanced.

[0077] Meanwhile, in a battery assembly (100) according to one embodiment of the present invention, the battery cells (110) may be arranged such that the folding portion (115) of the battery cell (110) faces upward and the side portion (114c) of the battery cell (110) faces downward. That is, the battery cells (110) may be arranged such that the folding portion (115) of the battery cell (110) faces upward and the sealing portion of the side portion (114c) of the battery cell (110) faces downward.

[0078] The lower part of the battery cell (110) may be a sealing part where the sealing of the pouch case (114) is performed, and the upper part of the battery cell (110) may not be a sealing part but a folding part (115) where the pouch case (114) is folded. Accordingly, the battery cell (110) may be positioned so that the sealing part of the battery cell (110) faces the venting channel (VC) inside the pack housing (1100). Additionally, the sealing part of the battery cell (110) may be positioned to face the cell cover venting hole (220H) of the cell cover (200). Referring to FIG. 4, the sealing part is provided on one side (114c) of the battery cell (110), and the battery cell (110) may be positioned within the battery assembly (100) such that the sealing part of the one side (114c) faces downward and the folding part (115) of the battery cell (110) faces upward.

[0079] When a thermal event or thermal runaway occurs in the battery cell (110), venting gas is generated in the battery cell (110) and the internal pressure of the battery cell (110) increases. This venting gas can be discharged mainly through the sealing portion of the battery cell (110). That is, due to the increased internal pressure, the sealing is released in some parts of the sealing portion, and venting gas can be discharged through the released sealing portion.

[0080] In the battery assembly (100) according to the present embodiment, the battery cell (110) can be arranged such that the lower part of the battery cell (110) becomes a sealing part and the upper part of the battery cell (110) becomes a folding part (115). Through this arrangement, a “bottom venting” structure that discharges venting gas and particles generated in the battery cell (110) in a downward direction can be more clearly implemented. Each of the venting channels (VC) has an independent venting path that is not shared among them. Therefore, gas, particles, or flames are introduced into a venting channel (VC) that is in communication with the battery cell (110) where a thermal event has occurred, but such gas, particles, or flames do not propagate to an adjacent venting channel (VC). Consequently, gas, particles, or flames are not introduced into other battery cells (110) that are in communication with other venting channels (VC), and ultimately, the thermal event is not propagated or triggered to other battery cells (110).

[0081] In particular, each of the venting channels (VC) can be positioned to correspond to each of the battery cell units (110U). Each of the venting channels (VC) can be connected one-to-one with each of the battery cell units (110U). That is, the number of venting channels (VC) can correspond to the number of battery cell units (110U) within the battery cell stack (110A), and any one battery cell unit (110U) may be connected only to the venting channel (VC) located above it and not to other venting channels (VC).

[0082] High-temperature gas and flames generated in any one battery cell unit (110U) are discharged only through the venting channel (VC) connected thereto, and movement to other venting channels (VC) is restricted. As described above, in the battery cell stack (110A) according to the present embodiment, the battery cells (110) can form a battery cell unit (110U) by being housed in the cell cover (200). High-temperature gas or flames resulting from a thermal runaway phenomenon generated in any one battery cell unit (110U) are blocked by the side portion (210) of the cell cover (200) and cannot propagate to an adjacent battery cell unit (110U). Additionally, since the opening (201) of the cell cover (200) is also blocked by the expansion of the foam layer (120), they cannot be discharged in the direction in which the electrode lead (111) is positioned.

[0083] When high-temperature gas or flame is discharged from the upper part of the corresponding battery cell unit (110U) into a venting channel (VC) that corresponds one-to-one, the high-temperature gas or flame does not flow into an adjacent venting channel (VC) because each of the venting channels (VC) has an independent venting path that is not shared among them. Therefore, there is no risk of high-temperature gas or flame flowing back into an adjacent venting channel (VC) or another battery cell unit (110U) located above it. If the venting paths of the venting channels (VC) were shared among them, the battery cell unit (110U) that has not experienced thermal runaway would be at risk of the generated high-temperature gas or flame flowing into it because its internal pressure is relatively lower compared to the battery cell unit (110U) that has experienced thermal runaway. In this embodiment, by implementing an independent venting path for each battery cell unit (110U), the transfer of thermal runaway between battery cells (110) is minimized and structural collapse of the battery pack can be prevented.

[0084] In the battery pack (1000) according to the present 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 encloses the battery cells (110). A plurality of battery cells (110) in the battery cell unit (110U) may be covered by a cell cover (200). Each of the venting channels (VC) may be positioned to correspond to each of these battery cell units (110U). One venting channel (VC) may correspond to multiple battery cells (110) within the battery cell unit (110U). Thus, the number of battery cells (110) may be greater than the number of venting channels (VC).

[0085] If the number of battery cells (110) and the number of venting channels (VC) are set to be the same so that one venting channel (VC) corresponds to each individual battery cell (110), it becomes structurally complex and inefficient because a large number of independent venting channels (VC) must be provided. Accordingly, in this embodiment, multiple battery cells (110) are grouped to form a battery cell unit (110U), and each venting channel (VC) is provided to correspond to each of these battery cell units (110U), thereby enabling the efficient implementation of independent venting channels (VC).

[0086] 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 a battery assembly (100) is placed and side portions (1110, 1120, 1130, 1140) extending along the edges 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), a fourth side portion (1140), and a bottom frame (1150). The first to fourth side portions (1110, 1120, 1130, 1140) may be arranged along the four sides of the edges of the bottom frame (1150), which is rectangular in shape. The battery assembly (100) can be seated in the internal space formed by the bottom frame (1150) and the first to fourth side parts (1110, 1120, 1130, 1140).

[0087] Additionally, the open top of the pack housing (1100) may be covered by a pack cover (1200). Although not specifically illustrated, a gasket may be interposed between the first to fourth side portions (1110, 1120, 1130, 1140) of the pack housing (1100) and the pack cover to increase sealing performance.

[0088] Additionally, a second thermally conductive resin layer (620) may be further disposed between the pack cover (1200) and the battery assembly (100). That is, as disclosed in FIG. 9, a second thermally conductive resin layer (620) may be further formed on the upper surface of the battery assembly (100) exposed to the open upper surface of the pack housing (1100). Since this second thermally conductive resin layer (620) is formed by sequentially contacting 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 side of the upper surface, it can effectively cool the heat generated inside the battery assembly (100) and release it to the outside. Additionally, for further cooling, a cooling member (not shown) may be further included on the upper surface of the battery assembly (100). As a structure of “bottom venting” is implemented to discharge 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), the cooling member may be located at the top rather than the bottom of the battery assembly (100). As long as the cooling member can cool the heat generated in the battery assembly (100), there are no special restrictions on its form or method. For example, the cooling member may be a heat sink through which a refrigerant circulating inside flows. Furthermore, the cooling device is not limited to this and can be applied in various forms.

[0089] The bottom frame (1150) according to the present embodiment may include a venting plate (1151) on which a 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 venting channels (VCs) described above may be formed in this venting unit (1300).

[0090] In the battery pack structure of “bottom venting,” the space between the venting plate (1151) and the bottom plate (1152) is utilized as a space where gas or flame flows, i.e., where a venting channel (VC) is formed. Additionally, the venting unit (1300) can implement this space as a venting channel (VC) of an independent venting path that is not shared with one another. Furthermore, the previously described opening (1151P) can be formed in the venting plate (1151) of the bottom frame (1150). That is, the venting plate (1151) may include an opening (1151P) formed in a portion corresponding to the venting hole (300VH) of the battery assembly (100), and the venting hole (300VH) may be connected to the venting channel (VC) through the opening (1151P). The opening (1151P) may be formed by opening at least a portion of the area corresponding to the venting channel (VC) within the venting plate (1151). There are no specific limitations on the number or area of ​​the opening (1151P). The flange portion (300F) provided on the outer perimeter of the venting hole (300VH) may be inserted into the venting channel (VC) while passing through the opening (1151P) of the bottom frame (1150).

[0091] As described above, according to an embodiment of the present invention, even if a thermal event occurs in some cells and high-temperature gas, flames, and particles are generated, it is possible to discharge them in an intended direction and to discharge them to the outside through a flow path formed in the battery pack. In particular, in this process, the high-temperature gas, etc., are not only blocked from being transmitted to adjacent battery cell units by the cell cover, but the opening of the cell cover is also blocked by the expansion of the foam layer, thereby allowing for more effective control of gas venting and thus improving the safety of the battery assembly and battery pack.

[0092] In this embodiment, terms indicating directions such as front, back, left, right, up, and down have been used; however, these terms are for convenience of explanation only and may vary depending on the location of the object or the position of the observer.

[0093] The above battery assembly or battery pack can be applied to various devices. Specifically, it can be applied to means of transportation such as electric bicycles, electric vehicles, and hybrids, or to Energy Storage Systems (ESS), but is not limited thereto and can be applied to various devices capable of using secondary batteries.

[0094] Although 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 by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention. Explanation of the symbols

[0095] 100: Battery assembly 110: Battery cell 110U: Battery cell unit 110A: Battery cell stack 120: Foam layer 130: Blockage prevention layer 200: Cell Cover 300: Storage Frame 400: Pad 1000: Battery pack

Claims

Claim 1 A battery assembly comprising at least one battery cell, a plurality of battery cell units including cell covers covering the bottom surface and both sides of the at least one battery cell, and a first thermally conductive resin layer disposed on the top of the battery cell, wherein the cell cover includes at least one cell cover venting hole in a bottom surface corresponding to the bottom surface of the battery cell, electrode leads protrude from both ends in the longitudinal direction of the battery cell, and a foam layer disposed adjacent to the electrode leads of at least one of the at least one battery cell, wherein the cell cover includes two openings that expose the electrode leads, and the foam layer expands in volume at a high temperature to block the two openings. Claim 2 delete Claim 3 delete Claim 4 A battery assembly according to claim 1, wherein the cell cover includes a side portion that extends vertically from the lower surface and corresponds to both sides of the battery cell, and the upper end of the side portion contacts the first thermally conductive resin layer. Claim 5 A battery assembly according to claim 1, further comprising a blockage prevention ridge disposed adjacent to the cell cover venting hole adjacent to the electrode lead among the at least one cell cover venting hole. Claim 6 A battery assembly according to claim 1, further comprising a storage frame for accommodating a plurality of battery cell units, wherein the storage frame comprises at least one venting hole formed at a position corresponding to the cell cover venting hole on the lower surface of the storage frame. Claim 7 A battery assembly described in claim 1; and a battery pack comprising a pack housing that accommodates the battery assembly. Claim 8 A battery pack according to claim 7, further comprising a plurality of venting channels communicating with the cell cover venting hole and extending from the inside of the bottom frame of the pack housing. Claim 9 In paragraph 8, each of the above venting channels is a battery pack that communicates one-to-one with each of the above battery cell units. Claim 10 In claim 8, the battery assembly further comprises a storage frame that accommodates 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 is a battery pack communicating with the venting hole. Claim 11 In claim 10, the battery assembly further comprises a first thermally conductive resin layer disposed between the upper part of the battery cell and the upper surface of the storage frame, and further comprises a pack cover disposed on the outside of the storage frame and coupled to the upper part of the pack housing. Claim 12 A 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 storage frame.

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