Battery assembly and battery pack comprising same

Abstract

A battery assembly, according to one embodiment of the present invention, is a battery assembly comprising a plurality of battery cell units, each including at least one battery cell and a cell cover that surrounds the lower 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 portion thereof corresponding to the bottom surface of the battery cell, electrode leads protrude from both end surfaces of the battery cell in the longitudinal direction, and a foam layer is disposed adjacent to at least one of the electrode leads of the at least one battery cell.

Description

Battery assembly and battery pack including same

[0001] Cross-citation with related application(s)

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0172420, filed December 1, 2023, and Korean Patent Application No. 10-2024-0162319, filed November 14, 2024, the entire contents of which are incorporated herein by reference.

[0003] 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, which improve safety by inducing gas venting in a desired direction in a thermal runaway situation.

[0004] In modern society, the widespread use of portable devices like cell phones, laptops, camcorders, and digital cameras has fueled active development of technologies related to these devices. Furthermore, rechargeable secondary batteries are increasingly being used as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (P-HEVs) to address air pollution caused by conventional gasoline-powered vehicles. This, in turn, heightens the need for further development of these batteries.

[0005] Currently commercialized secondary batteries include nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries are receiving attention for their advantages of being able to charge and discharge freely, having a very low self-discharge rate, and having a high energy density, as they have almost no memory effect compared to nickel-based secondary batteries.

[0006] These lithium secondary batteries primarily use lithium oxide and carbon materials as the positive and negative electrode active materials, respectively. The lithium secondary battery comprises an electrode assembly comprising a positive electrode plate and a negative electrode plate, each coated with the positive and negative electrode active materials, with a separator interposed between them, and a battery case that seals and houses the electrode assembly together with an electrolyte.

[0007] In general, lithium secondary batteries can be classified into can-type secondary batteries in which the electrode assembly is built into a metal can and pouch-type secondary batteries in which the electrode assembly is built into a pouch of an aluminum laminate sheet, depending on the shape of the outer packaging material.

[0008] In the case of secondary batteries used in small devices, 2-3 battery cells are arranged, but in the case of secondary batteries used in medium to large devices such as automobiles, a battery module in which multiple battery cells are electrically connected is used. Such a battery module improves capacity and output by forming a battery cell stack by connecting multiple battery cells in series or parallel. 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.

[0009] A battery pack includes battery modules as a sub-concept, and a battery module includes battery cells as a sub-concept. The number of battery cells contained in a battery module or the number of battery modules contained in a battery pack can vary depending on the output or capacity of the battery pack required for the electric vehicle.

[0010] However, for these battery packs, one of the most critical issues is safety. Specifically, if a thermal event occurs in one of the multiple battery cells contained within the pack, it is necessary to prevent the propagation of this thermal event to other cells and modules.

[0011] If thermal propagation between battery cells and modules is not properly controlled, this can lead to thermal events in other battery cells within the battery pack, potentially leading to more serious problems such as fire or explosion within the battery pack. Furthermore, fire or explosion occurring within the battery pack can cause significant damage to people and property in the surrounding area. Therefore, these battery packs require a configuration capable of appropriately controlling the aforementioned thermal events and their propagation.

[0012] The problem to be solved by the present invention is to provide a battery assembly and a battery pack including the same, which can prevent the thermal event from propagating to other adjacent battery cells and battery assemblies by venting gas, particles, flames, etc. only in a specific intended direction and thereby moving along a predetermined path and discharging them to the outside when a thermal event occurs in a specific battery cell.

[0013] However, the problems to be solved by the embodiments of the present invention 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.

[0014] A battery assembly according to one embodiment of the present invention comprises a plurality of battery cell units including at least one battery cell and a cell cover covering a lower surface and both sides of the at least one battery cell, wherein the cell cover includes at least one cell cover venting hole in a lower surface portion corresponding to a lower surface of the battery cell, and an electrode lead protrudes from both longitudinal cross sections of the battery cell, and includes a foam layer disposed adjacent to the electrode lead of at least one of the at least one battery cell.

[0015] The above cell cover includes openings on both sides exposing the electrode leads, and the foam layer can expand in volume at high temperatures to block the openings on both sides.

[0016] The above battery assembly may further include a first thermally conductive resin layer disposed on top of the battery cell.

[0017] The above cell cover extends vertically from the lower surface and includes side portions corresponding to both sides of the battery cell, and an upper end of the side portion can be in contact with the first thermally conductive resin layer.

[0018] The above battery assembly may further include an occlusion prevention step disposed adjacent to the cell cover venting hole adjacent to the electrode lead among the at least one cell cover venting hole.

[0019] The battery assembly further includes a storage frame that accommodates 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.

[0020] A battery pack according to one embodiment of the present invention includes the battery assembly and a pack housing that accommodates the battery assembly.

[0021] The battery pack may further include a plurality of venting channels extending from the interior of the bottom frame of the pack housing and communicating with the cell cover venting holes.

[0022] Each of the above venting channels can be connected one-to-one with each of the above battery cell units.

[0023] The battery assembly further includes a receiving 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.

[0024] The battery assembly may further include 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.

[0025] 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.

[0026] According to embodiments of the present invention, when a thermal event occurs in a specific battery cell, the venting gas, particles, or flames are vented only in a specific intended direction, thereby moving along a predetermined path and being discharged to the outside, thereby minimizing the propagation of the thermal event to other adjacent battery cells and battery assemblies.

[0027] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0028] Figure 1 is a perspective view showing a battery assembly according to one embodiment of the present invention.

[0029] Figure 2 is an exploded perspective view of the battery assembly of Figure 1.

[0030] Figure 3 is a plan view showing a battery cell included in the battery assembly of Figure 2.

[0031] 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.

[0032] FIG. 5 is an exploded perspective view of a battery cell unit included in the battery cell stack of FIG. 4.

[0033] Figure 6 (a) is a perspective view of the cell cover of Figure 5 viewed from a different angle, and Figure 6 (b) is a cross-sectional view showing a cross-section taken along the cutting line A-A' of Figure 5.

[0034] 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.

[0035] Figure 8 is an exploded perspective view showing a battery pack according to another embodiment of the present invention.

[0036] Fig. 9 is a cross-sectional view showing a cross-section taken along the cutting line B-B' of Fig. 8.

[0037] 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 invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0038] In order to clearly explain the present invention, parts that are not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0039] Furthermore, the sizes and thicknesses of each component shown in the drawings are arbitrarily indicated for convenience of explanation, and thus the present invention is not necessarily limited to the illustrated components. In the drawings, the thicknesses are enlarged to clearly represent various layers and regions. Furthermore, in the drawings, the thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0040] Furthermore, when we say that a layer, membrane, region, plate, or other part is "on" or "over" another part, this includes not only cases where it is "directly on" the other part, but also cases where there are other parts in between. Conversely, when we say that a part is "directly on" another part, it means that there are no other parts in between. Furthermore, saying that a part is "on" or "over" a reference part means that it is located above or below the reference part, and does not necessarily mean that it is located "above" or "over" the direction opposite to gravity.

[0041] Additionally, throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0042] Additionally, throughout the specification, when we say "in plan", we mean when the target portion is viewed from above, and when we say "in cross section", we mean when the target portion is viewed from the side in a cross-section cut vertically.

[0043] Hereinafter, a battery assembly according to one embodiment of the present invention will be described with reference to FIGS. 1 to 6.

[0044] 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, and FIG. 6 (b) is a cross-sectional view showing a cross-section taken along the cutting line A-A' of FIG. 5.

[0045] Referring to FIGS. 1 to 5, battery cells (110) according to the present embodiment can be stacked along one direction to form a battery cell stack (110A). Hereinafter, the battery cells (110) will first be described.

[0046] The battery cell (110) according to the present embodiment may be a battery cell of various shapes, for example, a pouch-shaped battery cell, a square battery cell, or a cylindrical battery cell. For example, as illustrated in FIG. 3, the battery cell (110) according to the present embodiment may be a pouch-shaped battery cell. Hereinafter, a pouch-shaped battery cell will be described, but the battery cell (110) according to the present embodiment is not limited thereto, and various types of battery cells may be applied.

[0047] The battery cell (110) according to the present embodiment may be in the form of an electrode assembly having electrode leads (111) protruding in one or both directions, housed in a pouch case (114). Such a battery cell (110) may have a rectangular sheet shape. The battery cell (110) may be formed by housing the electrode assembly in a pouch case (114) of a laminate sheet including 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.

[0048] The battery cell (110) can be manufactured by bonding the opposite ends (114a, 114b) of the pouch case (114) and one side (114c) connecting them while the electrode assembly (not shown) is housed in the pouch case (114). In other words, the battery cell (110) according to one embodiment of the present invention has a total of three sealing portions corresponding to the opposite ends (114a, 114b) and one side (114c), and the sealing portions have a structure in which they are sealed by a method such as fusion, and the remaining other side portion may be formed as a folding portion (115). That is, the battery cell (110) according to the present embodiment can 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 the sealing portion.

[0049] The pouch case (114) of the laminate sheet may include an inner resin layer for sealing, a metal layer for preventing penetration of materials, and an outermost outer resin layer. Based on the electrode assembly inside the pouch case (114), the inner resin layer may be positioned at the innermost side, the outer resin layer may be positioned at the outermost side, and the metal layer may be positioned between the inner resin layer and the outer resin layer.

[0050] The outer resin layer may have excellent tensile strength and weather resistance relative to its thickness and may exhibit electrical insulation properties to protect the electrode assembly from the outside. The 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. The metal layer may include aluminum (Al). The inner resin layers may be thermally bonded to each other by heat and / or pressure applied while the electrode assembly is embedded. The inner resin layer may include cast polypropylene (CPP) or polypropylene (PP).

[0051] A pouch case (114) may be divided into two parts, and a concave receiving portion in which an electrode assembly can be mounted may be formed in at least one of the two parts. Along the outer periphery of the receiving portion, the inner resin layers of the two parts of the pouch case (114) may be bonded to each other to form a sealing portion. In this manner, the pouch case may be sealed, and a battery cell (110), which is a pouch-type secondary battery, may be manufactured.

[0052] Within the battery cell stack (110A), the battery cells (110) may be configured in plurality. The plurality of battery cells (110) may be stacked so as to be electrically connected to each other. In particular, the plurality of battery cells (110) may be stacked in a direction parallel to the x-axis while standing upright. Accordingly, the electrode leads (111) may protrude in a direction perpendicular to the direction in which the battery cells (110) are stacked. 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. If the electrode leads (111) are battery cells 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.

[0053] 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, and FIG. 5 is an exploded perspective view of a battery cell unit included in the battery cell stack of FIG. 4.

[0054] Referring to FIGS. 4 and 5 together, in the battery cell stack (110A) according to the present embodiment, the battery cells (110) may be stacked to form a battery cell unit (110U). Specifically, the battery assembly (100) according to the present embodiment may include a plurality of battery cell units (110U), and the battery cell unit (110U) may include at least one battery cell (110) and a cell cover (200) that partially surrounds at least one battery cell (110).

[0055] That is, according to the present embodiment, a battery cell unit (110U) is formed when one or more battery cells (110) are arranged inside a cell cover (200), and a battery cell stack (110A) can be formed when these battery cell units (110U) are stacked along one direction.

[0056] Within the battery cell unit (110U), the battery cell (110) may be configured as one or more. FIG. 4 illustrates, as an example, a battery cell unit (110U) including three battery cells (110). The plurality of battery cells (110) may be stacked so as to be electrically connected to each other. In particular, the plurality of battery cells (110) may be stacked along a direction parallel to the x-axis, with one side of the cell body (113) facing each other, within the battery cell unit (110U).

[0057] Figure 6 (a) is a perspective view of the cell cover of Figure 5 viewed from a different angle, and Figure 6 (b) is a cross-sectional view showing a cross-section taken along the cutting line A-A' of Figure 5.

[0058] Referring to (a) and (b) of FIG. 6 together, the cell cover (200) according to the present embodiment may include side portions (210) that cover one side of the battery cell (110). In addition, the cell cover (200) may include a lower portion (220) that connects the side portions (210) and covers the lower portion of at least one battery cell (110).

[0059] The cell cover (200) may include two side portions (210) and one lower portion (220). One side of the side portions (210) and one side of the lower portion (220) may be perpendicular, and the side portions (210) may extend upward from opposite sides of the lower portion (220), respectively. The cell cover (200) according to the present embodiment may have an open upper side. That is, when the cell cover (200) is cut along the xz plane in FIG. 5, the cell cover (200) may have a 'U' shape. The cell cover (200) may be arranged to surround at least a portion of three of the four sides of a six-sided battery cell (110), excluding two sides on which electrode leads (111) are formed. In this embodiment, the three sides of the bare AJ sheet are provided to surround the two sides on which the electrode leads (111) are formed and the upper side of the battery cell (110), that is, the side in the +Z direction of the Z-axis.

[0060] Corresponding to the two surfaces on which the electrode leads (111) are formed, an open portion (201) defined by two side portions (210) and one lower portion (220) is formed on both sides. That is, an open portion (201) is formed at both ends in the Y-axis direction in the drawing. The electrode leads (111) can be exposed through the open portion (201).

[0061] Adjacent to the electrode lead (111), a foam layer (120) is formed between the side portion (210) and the battery cell (110). As described below, the foam layer (120) expands during thermal runaway to block the opening (201), thereby allowing venting gas and the like to be directed in a specific direction. The foam layer (120) will be described in more detail later.

[0062] Meanwhile, as described above, since the battery cells (110) are positioned between the side portions (210) of the cell covers (200), the battery cells (110) within the battery cell stack (110A) can be divided into battery cell units (110U). By dividing the battery cells (110) within 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 battery cell (110), the propagation of the thermal event or thermal runaway to the battery cells (110) of another adjacent battery cell unit (110U) is blocked because the side portions (210) of the cell covers (200) are positioned in the direction in which the battery cells (110) are stacked.

[0063] The cell cover (200) can not only delay the thermal runaway phenomenon, but also supplement the rigidity of the battery cell (110), thereby allowing the battery cell (110) to remain upright. 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 upright state of the battery cell (110) can be maintained by supporting the side surfaces (210) of the cell cover (200) of the battery cell (110).

[0064] The cell cover (200) may be manufactured from a material that has a high melting point so as not to melt even in the event of thermal runaway and can block the propagation of a thermal event or thermal runaway. In addition, the cell cover (200) may be manufactured from 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 impact, etc. There is no particular limitation on the material used for the cell cover (200), but for example, it may include at least one of mica (MICA) material, steel, aluminum (Al), or plastic material.

[0065] A pad (400) may be interposed between battery cell units (110U), i.e., between cell covers (200). In addition, a pad (400) may also be interposed on the outer surface of the cell cover (200) of the outermost battery cell unit (110U). This pad (400) may function as a thermal barrier that can block the propagation of a thermal event or thermal runaway. That is, there is no particular limitation on the material of the pad (400) according to the present embodiment as long as it can exhibit a predetermined insulating performance. For example, the pad (400) may include a silicon (Si) material or an aerogel material.

[0066] Meanwhile, a cell cover venting hole (220H) may be formed in the lower surface (220) of the cell cover (200) according to the present embodiment. When a thermal event causes high-temperature gas, particles, or flames to occur in one battery cell (110), as described above, the side surface (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 discharged through the cell cover venting hole (220H) formed in the lower surface (220). This cell cover venting hole (220H) may be communicated with a venting hole (300VH) provided in the lower surface of the battery assembly (100).

[0067] At this time, high-temperature gas, particles or flames may be discharged through the cell cover venting hole (220H), but since the cell cover (200) includes an opening (201) that exposes the electrode lead (111) as described above, there is a possibility that the 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, since the foam layer (120) is disposed adjacent to the electrode lead (111) as described above, it is possible to block this possibility and discharge the high-temperature gas, particles or flames only in the intended direction, i.e., the cell cover venting hole (220H).

[0068] To this end, the foam layer (120) may be formed of a foamable material capable of expanding at high temperatures. For example, a silicone-based material or a graphite-based material may be used, and in particular, a heat-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 may be formed by attaching a tape or the like made of a foamable material, and is not particularly limited thereto.

[0069] The foam layer (120) can expand in volume in a high-temperature environment, thereby filling the space between the electrode lead (111) and the side portion (210) of the cell cover (200) and blocking the opening (201). Therefore, when thermal runaway occurs, the venting gas can be prevented from venting toward the electrode lead (111), and can be induced to vent in the intended direction, i.e., toward the cell cover venting hole (220H).

[0070] Meanwhile, such a battery cell stack (110A) is stored in a storage frame (300) or is formed into a battery assembly (100) on its own. That is, a plurality of battery cell stacks (110A) may be provided to directly form a battery pack (1000), or a plurality of them may be provided by being stored 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 a battery pack (1000), the number of parts is reduced, thereby reducing cost and weight and increasing energy density. If the battery pack (1000) is formed after being stored in the storage frame (300), it may be advantageous in disassembly and reassembly, etc. Hereinafter, a case in which a battery pack (1000) is formed by being stored in the storage frame (300) will be described as an example, but the present invention 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 an 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) to communicate with the cell cover venting hole (220H) of the cell cover (200). Specifically, the 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 a pack housing of a battery pack, which will be described later, to discharge high-temperature gas, particles, or flames generated by a thermal event in a specific battery cell (110) to the outside. This will be described in more detail later.

[0071] In addition, the lower surface, i.e., the inner surface, of the upper frame (310) faces the upper portion of the cell cover (200). The upper portion of the cell cover (200) is open, thereby exposing the upper portion of the battery cell (110). 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 portion of the upper frame (310). The 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), thereby covering the upper portion of the open cell cover (200). As a result, the battery cell unit (110U) can be fixed, and at the same time, heat generated inside the battery cell unit (110U) can be cooled, while preventing venting gas from being discharged to the upper portion when a thermal event occurs.

[0072] In the battery cell stack (110A), a busbar frame (500) may be arranged on one or both sides in the direction in which the electrode leads (111) protrude. For example, in the battery cell (110) according to the present embodiment, the electrode leads (111) may protrude in both directions, i.e., in the y-axis direction and the -y-axis direction. Accordingly, a busbar frame (500) may be arranged on each of the y-axis direction and the -y-axis direction of the battery cell stack (110A).

[0073] A bus bar (510) and a terminal bus bar (520) may be mounted on the opposite side of the side facing the battery cell stack (110A) among the bus bar frames (500). The electrode leads (111) may be connected to the bus bar (510) or the terminal bus bar (520) by passing through the slits formed in the bus bar frame (500) and then being bent. There is no particular limitation on the form in which the electrode leads (111) are connected to the bus bar (510) or the terminal bus bar (520) as long as electrical connection is possible, and for example, welding may be performed. The battery cells (110) within the battery cell stack (110A) may be electrically connected to each other using the bus bar (510). Meanwhile, as illustrated 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 or electrical components through the terminal bus bar (520).

[0074] Meanwhile, according to the present embodiment, even if a thermal event occurs in some battery cells (110), since the opening (201) of the cell cover (200) where the electrode leads (111) are formed is blocked by the expansion of the foam layer (120), high-temperature gas, particles or flames generated by the thermal event can be prevented from being discharged to the outside of the electrode leads (111), and thus damage to the bus bar frame (500) and various components included therein arranged on the outside in the corresponding direction can also be prevented.

[0075] According to one embodiment of the present invention, the foam layer (120) positioned adjacent to the 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) by expanding at high temperatures, and venting can be performed only in the intended direction (cell cover venting hole (220H) of the lower surface (220), thereby improving safety through control of the venting gas.

[0076] Hereinafter, a battery assembly according to another embodiment of the present invention will be described with reference to FIG. 7.

[0077] 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.

[0078] 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 occlusion prevention bump (130), and only this will be described.

[0079] That is, as illustrated in FIG. 7, among the cell cover venting holes (220H), an occlusion prevention bump (130) may be included adjacent to the cell cover venting hole (220H) adjacent to the electrode lead (111). The occlusion prevention bump (130) prevents the material of the expanded foam layer (120) from flowing into the cell cover venting hole (220H) and occluding the cell cover venting hole (220H) when the volume of the foam layer (120) expands at a high temperature. To this end, the occlusion prevention bump (130) may be arranged so as to be interposed between the cell cover venting hole (220H) and the foam layer (120). In addition, the occlusion prevention bump (130) may be formed of a material having excellent heat resistance, and for example, may be formed by attaching a pad made of a heat-resistant resin, or by attaching a pad of the same material as the cell cover (200), but is not particularly limited thereto.

[0080] By further including the occlusion prevention barrier (130) in this way, it is possible to prevent an undesirable portion, i.e., the cell cover venting hole (220H), from being occluded by the expansion of the foam layer (120), and to more effectively guide the venting gas in the intended direction by occluding only the opening (201) of the cell cover (200).

[0081] Hereinafter, a battery pack according to another embodiment of the present invention will be described with reference to FIGS. 8 and 9.

[0082] 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 taken along the cutting line B-B' of FIG. 8.

[0083] Referring to FIGS. 8 and 9, a battery pack (1000) according to one embodiment of the present invention includes at least one battery assembly (100) as described above; and a pack housing (1100) that accommodates at least one battery assembly (100). A plurality of venting channels (VC) extending in one direction are formed inside the pack housing (1100), and the venting channels (VC) are connected to the venting holes (300VH) of the battery assembly (100) described above. Each of the venting channels (VC) has an independent venting path that is not shared with each other.

[0084] 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 a venting channel (VC). Here, the particles may be metal particles. The venting channels (VC) do not share a 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 another adjacent venting channel (VC), thereby minimizing the propagation of a thermal event occurring in a specific battery cell (110) to other battery cells (110).

[0085] 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). In addition, an opening (1151P) may be 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 inside of the venting channel (VC). Specifically, a venting hole (300VH) formed in the lower frame (320) of the receiving frame (300) may be communicated with the venting channel (VC) through the opening (1151P) of the bottom frame (1150). In addition, 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 communicated 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 be positioned corresponding to the venting hole (300VH).

[0086] Accordingly, 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 may flow into the venting channels (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 flowing into the venting channels (VC) are discharged to the outside of the battery pack (1000). The battery pack (1000) according to the present embodiment has a “lower 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, in the upper region of the battery assembly (100), there is a high-voltage current path, such as the HV (High voltage) connection of the terminal bus bar. Here, the HV connection is a connection that serves as a power source to supply power that requires high voltage, and refers to a connection between battery cells or a connection between battery assemblies. At this time, if high-temperature gas or particles, etc. due to a thermal event of 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 explosion and flame generation. On the other hand, in the case of the battery pack according to the present embodiment, as mentioned above, since it has a “bottom venting” structure, high-temperature gas or particles, etc. due to 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, etc. coming into contact with a high-voltage path, such as the HV connection, and ultimately, safety against thermal runaway phenomenon can be enhanced.

[0087] Meanwhile, in the 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 cells (110) faces upward and one side (114c) of the battery cells (110) faces downward. That is, the battery cells (110) may be arranged such that the folding portion (115) of the battery cells (110) faces upward and the sealing portion of the one side (114c) of the battery cells (110) faces downward.

[0088] The lower part of the battery cell (110) may be a sealing part where the pouch case (114) is sealed, and the upper part of the battery cell (110) may not be a sealing part but may be a folding part (115) where the pouch case (114) is folded. Accordingly, the battery cell (110) may be arranged so that the sealing part of the battery cell (110) faces the venting channel (VC) inside the pack housing (1100). In addition, the sealing part of the battery cell (110) may be arranged so as to face the cell cover venting hole (220H) of the cell cover (200). Referring to FIG. 4, a 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) so that the sealing part of the one side (114c) faces downward and the folding part (115) of the battery cell faces upward.

[0089] When a thermal event or thermal runaway occurs in a 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 mainly discharged through the sealing portion of the battery cell (110). That is, due to the increased internal pressure, the sealing portion of the sealing portion is released, and the venting gas, etc. can be discharged through the released sealing portion.

[0090] In the battery assembly (100) according to the present embodiment, the battery cells (110) may be arranged so that the lower portions of the battery cells (110) become the sealing portions and the upper portions of the battery cells (110) become the folding portions (115). Through this arrangement, a “lower venting” structure that discharges venting gases and particles, etc. generated in the battery cells (110) downwards can be more clearly implemented. Each of the venting channels (VC) has an independent venting path that is not shared with each other. Therefore, although gas, particles, or flames flow into one of the venting channels (VC) that is connected to the battery cell (110) where the thermal event has occurred, such 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) that are connected to other venting channels (VC), and ultimately, thermal events do not propagate or trigger to other battery cells (110).

[0091] In particular, each of the venting channels (VC) may be positioned to correspond to each of the battery cell units (110U). Each of the venting channels (VC) may be connected one-to-one with each of the battery cell units (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 of the battery cell units (110U) may be connected only with the venting channel (VC) located above it, and may not be connected with other venting channels (VC).

[0092] High-temperature gas and flame generated from one battery cell unit (110U) are discharged only through the venting channel (VC) connected thereto, and are restricted from moving to other venting channels (VC). 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) while being accommodated in the cell cover (200). High-temperature gas or flame due to thermal runaway phenomenon generated in one battery cell unit (110U) is blocked by the side portion (210) of the cell cover (200), and cannot spread to another adjacent battery cell unit (110U). In addition, since the opening (201) of the cell cover (200) is also blocked by the expansion of the foam layer (120), the gas and flame cannot be discharged in the direction in which the electrode lead (111) is arranged.

[0093] When high-temperature gas or flame is discharged from the upper portion of the corresponding battery cell unit (110U) to the corresponding venting channel (VC), the high-temperature gas or flame does not flow into the adjacent other venting channel (VC) because each of the venting channels (VC) has an independent venting path that is not shared with each other. Therefore, there is no risk of high-temperature gas or flame flowing back into the adjacent other venting channel (VC) and the other battery cell unit (110U) located thereon. If the venting paths of the venting channels (VC) are shared with each other, there is a risk of high-temperature gas or flame flowing into the inside of the battery cell unit (110U) where the thermal runaway phenomenon has not occurred because the internal pressure is relatively lower than that of the battery cell unit (110U) where the thermal runaway phenomenon has occurred. In the present embodiment, by implementing an independent venting path for each battery cell unit (110U), the transfer of thermal runaway between the battery cells (110) is minimized and the structural collapse of the battery pack is prevented.

[0094] 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). The battery cell unit (110U) may include a plurality of battery cells (110) and a cell cover partially covering the battery cells (110). In the battery cell unit (110U), a plurality of battery cells (110) may be covered by a cell cover (200). Each of the venting channels (VC) may be positioned to correspond to each of the battery cell units (110U). One venting channel (VC) may correspond to multiple 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).

[0095] 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. Therefore, in the present embodiment, multiple battery cells (110) are bundled to form a battery cell unit (110U), and each of the venting channels (VC) is provided to correspond to each of the battery cell units (110U), thereby efficiently implementing independent venting channels (VC).

[0096] Meanwhile, the pack housing (1100) according to an embodiment of the present invention may be a housing having 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, 1140) extending 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), 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 edge of the bottom frame (1150) having a rectangular shape. The battery assembly (100) can be installed in an internal space formed by the bottom frame (1150) and the first to fourth side portions (1110, 1120, 1130, 1140).

[0097] Additionally, the open upper portion 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 enhance sealing.

[0098] In addition, 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 portion of the battery assembly (100) exposed through the open upper portion 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. In addition, for additional cooling, a cooling member (not shown) may be further included on the upper portion of the battery assembly (100). As the “bottom venting” structure 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 can be positioned 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 is no particular limitation on its shape or method. For example, the cooling member can be a heat sink with a coolant flowing circulating therein. In addition, the cooling device is not limited thereto and can be applied in various forms.

[0099] The floor frame (1150) according to the present embodiment may include a venting plate (1151) on which the battery assembly (100) is placed and a lower plate (1152) positioned below the venting plate (1151). A venting unit (1300) may be positioned between the venting plate (1151) and the lower plate (1152), and the venting channels (VC) described above may be formed in the venting unit (1300).

[0100] In the battery pack structure of “lower venting”, the space between the venting plate (1151) and the lower plate (1152) is utilized as a space in which gas or flame flows, i.e., a venting channel (VC) is formed. In addition, the venting unit (1300) can implement this space as a venting channel (VC) of an independent venting path that is not shared between each other. In addition, the opening (1151P) described above can be formed in the venting plate (1151) of the bottom frame (1150). That is, the venting plate (1151) can include an opening (1151P) formed in a portion corresponding to the venting hole (300VH) of the battery assembly (100), and the venting hole (300VH) can be communicated with 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) among the venting plates (1151). There is no particular limitation on the number or area of ​​the openings (1151P). The flange portion (300F) provided on the outer periphery of the venting hole (300VH) may be inserted into the venting path of the venting channel (VC) while passing through the opening (1151P) of the floor frame (1150).

[0101] 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 discharge them to the outside through a path formed in the battery pack, and in particular, in this process, not only is the high-temperature gas blocked from being transmitted to an adjacent battery cell unit by the cell cover, but also the opening of the cell cover is closed by the expansion of the foam layer, so that the venting of the gas can be controlled more effectively, and thus the safety of the battery assembly and the battery pack can be improved.

[0102] In this example, terms indicating directions such as front, back, left, right, up, and down are used, but these terms are only for convenience of explanation and may vary depending on the location of the target object or the location of the observer.

[0103] The above battery assembly or battery pack can be applied to various devices. Specifically, it can be applied to transportation vehicles such as electric bicycles, electric vehicles, and hybrid vehicles, or to ESS (Energy Storage Systems), but is not limited thereto. It can also be applied to various devices that can use secondary batteries.

[0104] 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 using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

[0105] [Explanation of symbols]

[0106] 100: Battery assembly

[0107] 110: Battery cell

[0108] 110U: Battery cell unit

[0109] 110A: Battery cell stack

[0110] 120: Foam layer

[0111] 130: Anti-occlusion layer

[0112] 200: Cell Cover

[0113] 300: Storage Frame

[0114] 400: Pad

[0115] 1000: Battery pack

Claims

1. A battery assembly comprising a plurality of battery cell units, each of which includes at least one battery cell and a cell cover covering a lower surface and both sides of the at least one battery cell, The above cell cover includes at least one cell cover venting hole in the lower portion corresponding to the lower surface of the battery cell, Electrode leads protrude from both longitudinal cross sections of the above battery cell, A battery assembly comprising a foam layer positioned adjacent to at least one electrode lead of at least one battery cell.

2. In paragraph 1, The above cell cover includes openings on both sides exposing the electrode leads, A battery assembly in which the above foam layer expands in volume at high temperature to block the above-described openings on both sides.

3. In paragraph 1, A battery assembly further comprising a first thermally conductive resin layer disposed on top of the battery cell.

4. In paragraph 3, The above cell cover extends vertically from the lower surface and includes side portions corresponding to both sides of the battery cell, A battery assembly in which the upper part of the above side is in contact with the first thermally conductive resin layer.

5. In paragraph 1, A battery assembly further comprising an occlusion prevention step disposed adjacent to the cell cover venting hole adjacent to the electrode lead among the at least one cell cover venting hole.

6. In paragraph 1, Further comprising a storage frame for accommodating the plurality of battery cell units, A battery assembly, wherein the storage frame includes at least one venting hole formed at a position corresponding to the cell cover venting hole on the lower surface of the storage frame.

7. Battery assembly as described in paragraph 1; and A battery pack comprising a pack housing for housing the above battery assembly.

8. In paragraph 7, A battery pack further comprising a plurality of venting channels extending from the interior of the bottom frame of the pack housing and communicating with the cell cover venting holes.

9. In paragraph 8, A battery pack in which each of the above venting channels is connected one-to-one with each of the above battery cell units.

10. In paragraph 8, The battery assembly further includes a receiving 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, The above venting channel is a battery pack communicating with the above venting hole.

11. In Article 10, The above 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, A battery pack further comprising a pack cover disposed on the outside of the storage frame and coupled to the upper portion of the pack housing.

12. In Article 11, A battery pack 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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