Battery pack and device including same

Abstract

A battery pack, according to one embodiment of the present invention, comprises: a plurality of battery cells; a pack frame having an open upper portion so that the battery cells are mounted therein, or the battery cells are mounted therein in a state of being received in a module frame; and a pack cover for covering the pack frame. The pack cover comprises: a first plate; and a second plate located on the upper portion the first plate, wherein an insulating coating is formed on at least a portion of a surface of the first plate.

Description

Battery pack and device including same

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

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0021603, filed February 15, 2024, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a battery pack and a device including the same, and more particularly, to a battery pack capable of preventing external ignition and a device including the same.

[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, further fueling the growing need for secondary battery development.

[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 may be used. Such a battery module improves capacity and output by forming a battery cell stack by connecting multiple battery cells in series or parallel. In addition, one or more battery modules can be mounted together with various control and protection systems such as a BDU (Battery Disconnect Unit), a BMS (Battery Management System), and a cooling system to form a battery pack.

[0009] A battery pack may include battery modules as a sub-concept, and a battery module may include 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 may vary depending on the output or capacity of the battery pack required for the electric vehicle.

[0010] However, safety is a key issue for these battery packs. Specifically, if a thermal event occurs in at least one of the multiple battery cells contained within the pack, high-temperature venting gases and heat are generated.

[0011] Figure 1 is a cross-sectional view showing a conventional battery pack and a chassis inside a vehicle device.

[0012] Referring to Fig. 1, when an ignition phenomenon occurs in at least one battery cell inside a battery pack (1), high-temperature gas may be emitted from a conventional battery pack (1). A high-temperature spark generated due to ignition inside the battery pack (1) heats the surface of the battery pack (1), and the surface temperature of the battery pack (1) rises. An insulating coating may be formed on the surface of the battery pack (1), and when the surface temperature of the battery pack (1) exceeds the spontaneous ignition temperature of the insulating coating material, ignition may occur on the surface of the battery pack (1).

[0013] At this time, high-temperature gas may flow from inside the conventional chassis (10) to the surface of the conventional battery pack (1). At this time, a large flame may occur when the high-temperature gas meets the ignition generated on the surface of the battery pack (1). Since this flame may flow back into the interior of the battery pack (1) and lead to an explosion of the battery pack (1) and the device including the same, a method for preventing ignition on the surface of the battery pack is required.

[0014] The problem to be solved by the present invention is to provide a battery pack and a device including the same that can prevent ignition on the surface even if the battery cells inside ignite.

[0015] 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.

[0016] A battery pack according to one embodiment of the present invention comprises: a plurality of battery cells; a pack frame having an open upper portion, on which the battery cells are mounted or on which the battery cells are mounted in a state of being housed in a module frame; and a pack cover covering the pack frame. The pack cover comprises a first plate and a second plate positioned on an upper portion of the first plate, and an insulating coating is formed on at least a portion of a surface of the first plate.

[0017] The first plate and the second plate may include a metal material.

[0018] An insulating coating may not be formed on the surface of the second plate.

[0019] The second plate may include a metal material, and the metal material of the second plate may be exposed as is.

[0020] When the internal pressure of the pack frame increases, the first plate may bend toward the direction where the second plate is located, so that the first plate and the second plate may come into close contact with each other.

[0021] The second plate may have a greater elastic modulus than the first plate.

[0022] A venting portion may be provided in the above pack frame.

[0023] The second plate can be welded to an exposed portion of the surface of the first plate where an insulating coating is not formed.

[0024] The first plate and the second plate can be joined by physical binding force.

[0025] The above physical binding force may be a bolted fastening, a riveted fastening or a clamp fastening.

[0026] A gasket may be interposed between the first plate and the second plate or a sealant may be applied.

[0027] A device according to one embodiment of the present invention includes the battery pack.

[0028] According to embodiments of the present invention, by providing a pack cover including a first plate and a second plate in a battery pack, even if battery cells inside the battery pack ignite, ignition can be prevented from occurring on the surface of the pack cover.

[0029] 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.

[0030] Figure 1 is a cross-sectional view showing a conventional battery pack and a chassis inside a vehicle device.

[0031] Figure 2 is an exploded perspective view showing a battery pack according to one embodiment of the present invention.

[0032] FIG. 3 is a perspective view showing one of the battery cells included in the battery pack of FIG. 2.

[0033] Figure 4 is a perspective view showing a pack cover included in the battery pack of Figure 2.

[0034] Figure 5 is an exploded perspective view showing the pack cover of Figure 4.

[0035] FIGS. 6 and 7 are schematic drawings of a pack frame and a pack cover in a battery pack according to one embodiment of the present invention.

[0036] Fig. 8 is a partial cross-sectional view showing a cross-section taken along the cutting line A-A' of Fig. 4.

[0037] Figures 9 to 11 are cross-sectional views showing cross-sections of pack covers according to various embodiments of the present invention.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] Fig. 2 is an exploded perspective view showing a battery pack according to one embodiment of the present invention. Fig. 3 is a perspective view showing one of the battery cells included in the battery pack of Fig. 2.

[0045] Referring to FIGS. 2 and 3, a battery pack (1000) according to one embodiment of the present invention includes a plurality of battery cells (110); a pack frame (200) having an open top so that the battery cells (110) are mounted thereon or the battery cells (110) are mounted in a state of being housed in a module frame (120); and a pack cover (300) covering the pack frame (200).

[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 FIGS. 2 and 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 two ends (114a, 114b) of the pouch case (114) and one side (114c) connecting them while the electrode assembly (not shown) is stored 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 (114s), and the sealing portions (114s) have a structure in which they are sealed by a method such as fusion, and the remaining other side 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 stored inside the pouch case (114) and the outer periphery of the pouch case (114) is sealed to form the sealing portion (114s). In Fig. 3, only the sealing portions (114s) formed at both ends (114a, 114b) of the pouch case (114) are shown, and the sealing portion is not shown on the side facing the folding portion (115), but the sealing portion of the side facing the folding portion (115) is folded to one side after the sealing is completed for space utilization.

[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 (114s). 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] The battery cells (110) may be configured in multiples. For example, a plurality of battery cells (110) may be stacked along one direction so as to be electrically connected to each other, thereby forming a battery cell stack (110A). For example, a plurality of battery cells (110) may be stacked in an upright position along a direction parallel to the Y-axis.

[0053] For example, the battery cells (110) may be stacked from one side (220) of the pack frame (200) to the other side (220) in a state where one side thereof is perpendicular to the bottom (210) of the pack frame (200) described later. 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 toward the X-axis direction, and the other electrode lead (111) may protrude toward the -X-axis direction. If the battery cell has electrode leads (111) protruding only in one direction, the electrode leads (111) may protrude in the X-axis direction or the -X-axis direction.

[0054] As described above, in one embodiment of the present invention, a plurality of battery cells (110) can be directly mounted on the pack frame (200). In this way, the structure in which a plurality of battery cells (110) are directly mounted on the pack frame (200) is a so-called cell-to-pack (CTP) structure, in which the battery cells (110) are not stored in a specific module frame (120), but are directly placed on the pack frame (200) with only a minimal fixing structure.

[0055] Meanwhile, in another embodiment of the present invention, a plurality of battery cells (110) may be mounted on a pack frame (200) while being housed in a module frame (120). This embodiment is illustrated in FIG. 2. Specifically, a plurality of battery cells (110) may be stacked along one direction to form a battery cell stack (110A), and a battery module (100) may be formed when the battery cell stack (110A) is housed in the module frame (120). The battery cells (110) may be housed in the pack frame (200) in units of such battery modules (100).

[0056] The pack frame (200) according to the present embodiment may have a space for storing battery cells (110) or battery modules (100) therein, and may be of an open top type. Specifically, the pack frame (200) may include a bottom portion (210) on which battery cells (110) are directly placed or on which battery cells (110) are placed in the form of a battery module (100); and side portions (220) extending along the edge of the bottom portion (210). The side portions (220) may extend in a direction perpendicular to one surface of the bottom portion (210). In addition, the side portions (220) may extend along the edge of the bottom portion (210). An internal space of an open top type is provided by the bottom portion (210) and the side portions (220), and battery cells (110) or battery modules (100) may be stored in this internal space. The pack cover (300) according to the present embodiment can cover the open upper part of the pack frame (200) and can be combined with the side part (220) of the pack frame (200).

[0057] Fig. 4 is a perspective view showing a pack cover included in the battery pack of Fig. 2. Fig. 5 is an exploded perspective view showing the pack cover of Fig. 4.

[0058] Referring to FIGS. 2, 4, and 5 together, the pack cover (300) according to the present embodiment includes a first plate (310) and a second plate (320) positioned on top of the first plate (310). That is, the first plate (310) can directly cover the open top of the pack frame (200), and the second plate (320) can be positioned on top of the first plate (310).

[0059] Meanwhile, an insulating coating is formed on at least a portion of the surface of the first plate (310). The insulating coating is a coating layer containing an electrically insulating material, and there are no particular limitations on the electrically insulating material. Furthermore, there are no particular limitations on the method for forming the insulating coating on the surface of the first plate (310).

[0060] The first plate (310) and the second plate (320) according to the present embodiment may include a metal material. In addition, the pack frame (200) may also include a metal material. Since the first plate (310), the second plate (320), and the pack frame (200) include a metal material, the rigidity of the battery pack (1000) can be secured while reducing the weight of the battery pack (1000). For example, the first plate (310), the second plate (320), and the pack frame (200) may include an aluminum material.

[0061] However, since the first plate (310) is configured to directly face the battery cells (110) or the battery module (100), it may come into contact with the electrical connection paths of the battery cells (110) and cause a short circuit. Such a short circuit may cause ignition and explosion of the battery pack (1000). Therefore, in order to prevent the occurrence of a short circuit, an insulating coating is formed on at least a portion of the surface of the first plate (310). In addition, since the insulating coating is formed on the surface of the first plate (310) including a metal material, the first plate (310) can be prevented from being corroded.

[0062] However, as described above, in the event of ignition of the battery cells (110), the insulating coating formed on the surface of the first plate (310) may become a cause of ignition. Specifically, the high-temperature spark generated by the ignition of the battery cells (110) may heat the first plate (310) of the pack cover (300), and the surface temperature of the first plate (310) may rise. At this time, if the insulating material included in the insulating coating formed on the surface of the first plate (310) exceeds its spontaneous ignition temperature, ignition may occur on the surface of the first plate (310). If the high-temperature venting gas discharged from the battery pack (1000) meets the ignition generated on the surface of the first plate (310), a large flame may occur, and if this flame is reversely introduced into the interior of the battery pack (1000), it may lead to an explosion of the battery pack (1000) and a device including the same.

[0063] In order to prevent ignition on the surface of the pack cover (300) as described above, the pack cover (300) according to the present embodiment further includes a second plate (320) that covers the first plate (310) on top of the first plate (310). That is, the pack cover (300) according to the present embodiment may have a dual structure of the first plate (310) and the second plate (320).

[0064] Specifically, three elements are required for ignition: “combustible material,” “temperature above the ignition point,” and “oxygen.” In the battery pack (1000), among the three elements, the combustible material may correspond to the insulating coating formed on the surface of the first plate (310), and among the three elements, the temperature above the ignition point may be satisfied by an increase in the surface temperature of the first plate (310) due to ignition of the battery cells (110). In this situation, if oxygen is blocked, the elements for ignition are not satisfied, and ignition does not occur. Accordingly, in the battery pack (1000) according to the present embodiment, by arranging the second plate (320) on top of the first plate (310), the amount of oxygen on the surface of the first plate (310) is reduced, thereby attempting to block oxygen, one of the three elements for ignition.

[0065] Since the upper surface of the first plate (310) is covered by the second plate (320) and only a predetermined space or gap exists between the first plate (310) and the second plate (320), the amount of oxygen on the upper surface of the first plate (310) is reduced compared to when the upper surface of the first plate (310) is exposed to the atmosphere. That is, since the amount of oxygen is not sufficient to cause ignition, ignition is prevented from occurring on the surface of the first plate (310). In addition, even if a microflame occurs on the upper surface of the first plate (310), the second plate (320) can prevent the venting gas from coming into contact with the microflame.

[0066] For example, the first plate (310) and the second plate (320) may be plate-shaped members that are recessed upward. Accordingly, a predetermined space or gap may be provided between the first plate (310) and the second plate (320). The temperature of the first plate (310) increases significantly due to the influence of high-temperature venting gas and sparks when the battery cells (110) are ignited. However, since the second plate (320) is spaced apart from the first plate (310) to have a predetermined space, direct heat conduction from the first plate (310) to the second plate (320) is prevented.

[0067] Meanwhile, it is preferable that an insulating coating is not formed on the surface of the second plate (320) according to the present embodiment. That is, as described above, the second plate (320) may include a metal material, and the metal material of the second plate (320) may be exposed as is. Since the second plate (320) is not configured to directly face the battery cells (110) or the battery module (100), an insulating coating is unnecessary. If an insulating coating is formed on the surface of the second plate (320), the insulating material included in the insulating coating may become a combustible material, and thus, it is not possible to properly prevent ignition from occurring in the pack cover (300).

[0068]

[0069] Hereinafter, with reference to FIGS. 6 and 7, the blocking of ignition in the pack cover (300) of the battery pack (1000) according to the present embodiment will be described in detail.

[0070] FIGS. 6 and 7 are schematic drawings of a pack frame and a pack cover in a battery pack according to one embodiment of the present invention. In particular, FIGS. 6 and 7 illustrate cross-sections of a combined pack frame (200) and pack cover (300), but battery cells within the pack frame (200) are not illustrated. In addition, FIG. 6 illustrates a state before ignition occurs within the battery pack, and FIG. 7 illustrates a state after ignition occurs within the battery pack.

[0071] Referring to FIGS. 2, 4, and 7 together, as described above, a pack cover (300) including a first plate (310) and a second plate (320) covers the open upper portion of the pack frame (200). FIG. 6 illustrates a state before a thermal event occurs inside the battery pack (1000).

[0072] At this time, if a thermal event occurs in the battery cells (110) inside the pack frame (200), ignition may occur along with high-temperature venting gas and sparks inside the pack frame (200). As illustrated in FIG. 7, due to the venting gas generated inside the pack frame (200), the pressure inside the battery pack (1000) increases and the first plate (310) and the second plate (320) of the pack cover (300) may bend upward.

[0073] The venting gas can be discharged to the outside through a venting portion (200V, see FIG. 2) provided in the pack frame (200). For example, the venting portion (200V) can be formed on a side surface (220) of the pack frame (200). The venting portion (200V) in the present invention refers to a mechanism for discharging high-temperature venting gas and heat generated inside the battery pack (1000) to the outside of the battery pack (1000). That is, as long as it is possible to discharge high-temperature venting gas and heat generated inside the battery pack (1000) due to a thermal event, there is no particular limitation on the structure or shape of the venting portion (200V). For example, the venting portion (200V) can be a structure that ruptures when the internal pressure exceeds a certain level or a valve-shaped structure that opens. Figure 2 schematically illustrates three venting portions (200V) formed on the side portion (220).

[0074] Since the upper surface of the first plate (310) is covered by the second plate (320) and only a predetermined space (S') exists between the first plate (310) and the second plate (320), the amount of oxygen is insufficient, so that ignition does not occur in the pack cover (300). Accordingly, even if high-temperature venting gas is discharged to the outside of the battery pack (1000) through the venting portion (200V), the high-temperature venting gas can be prevented from igniting and leading to a large explosion.

[0075] More specifically, as illustrated in FIG. 6, before a thermal event occurs inside the battery pack (1000), a predetermined space (S) is maintained between the first plate (310) and the second plate (320). When a thermal event occurs in the battery cells (110) inside the pack frame (200), as illustrated in FIG. 7, the internal pressure of the pack frame (200) increases due to the venting gas generated inside the pack frame (200). When the internal pressure of the pack frame (200) increases, the first plate (310) bends toward the side where the second plate (320) is located, so that the first plate (310) and the second plate (320) can come into close contact with each other. That is, as the first plate (310) bends further, the space (S') between the first plate (310) and the second plate (320) becomes narrower than the space (S) illustrated in FIG. 6. Although both the first plate (310) and the second plate (320) can be bent upward, since the first plate (310) directly receives pressure from within the pack frame (200), the first plate (310) can be bent upward more than the second plate (320). This phenomenon may also occur even if the first plate (310) and the second plate (320) include the same metal material. This is because the first plate (310) is directly subjected to pressure from the venting gas.

[0076] As the space (S') between the first plate (310) and the second plate (320) narrows, the amount of oxygen between the first plate (310) and the second plate (320), i.e., the amount of oxygen on the upper surface of the first plate (310), decreases, and the possibility of ignition is significantly reduced.

[0077] In addition, a small amount of residual oxygen may cause a micro-flame to occur between the first plate (310) and the second plate (320), but since the first plate (310) and the second plate (320) are in close contact, it is difficult for high-temperature venting gas to flow between them. In other words, even if a micro-flame occurs, the micro-flame may be blocked by the second plate (320) from coming into contact with the venting gas discharged from the battery pack (1000).

[0078]

[0079] Meanwhile, according to another embodiment of the present invention, the second plate (320) may have a larger elastic modulus than the first plate (310). As described above, even if the first plate (310) and the second plate (320) include the same material, the first plate (310) can be sufficiently adhered to the second plate (320) because the first plate (310) is directly subjected to the pressure from the venting gas. However, in another embodiment of the present invention, in order to more clearly implement the effect of the first plate (310) being adhered to the second plate (320), the second plate (320) may be set to have a larger elastic modulus than the first plate (310).

[0080] The first plate (310) and the second plate (320) may include a metal material, and the second plate (320) may include a material having a higher elastic modulus than the first plate (310). A tensile strength test may be performed on an elastic body including a metal material, such as the first plate (310) or the second plate (320). Stress is applied to the elastic body and the resulting strain, which is the degree of deformation, is measured. The elastic body may pass through an elastic region where recovery is possible and reach a plastic region where recovery is impossible. At this time, the ratio of the stress value to the strain value, which is the slope in the elastic region, corresponds to the elastic modulus. In other words, the elastic modulus represents the degree of stress relative to the strain in the elastic region in a tensile strength test, etc. That is, the second plate (320) including a material with a higher elastic modulus has more rigidity than the first plate (310), so that when the same stress is applied, the second plate (320) undergoes less deformation and the first plate (310) undergoes more deformation.

[0081] If the second plate (320) has a greater elastic modulus than the first plate (310), there is no particular limitation on the range of the elastic modulus of each of the first plate (310) and the second plate (320). The range of the elastic modulus of each of the first plate (310) and the second plate (320) may vary depending on the capacity, shape, size, etc. of the battery pack (1000).

[0082] Since the second plate (320) includes a material having a higher elastic modulus than the first plate (310), when a similar stress is applied, the first plate (310) may be deformed more, and the second plate (320) may be deformed less than the first plate (310). Therefore, when the internal pressure of the pack frame (200) increases, the first plate (310) may be pressed further toward the second plate (320), and the space (S') between the first plate (310) and the second plate (320) may be further reduced. This may be more effective in preventing ignition from occurring in the pack cover (300).

[0083]

[0084] Fig. 8 is a partial cross-sectional view showing a cross-section taken along the cutting line A-A' of Fig. 4.

[0085] Referring to FIGS. 4, 5, and 8, in a pack cover (300) according to one embodiment of the present invention, a first plate (310) and a second plate (320) may be welded to each other. Specifically, the second plate (320) may be welded to an exposed portion (310E1) on the surface of the first plate (310) where an insulating coating (310C) is not formed. Hereinafter, the surface of the first plate (310) to which the second plate (320) is bonded is referred to as a first exposed portion (310E1).

[0086] As described above, an insulating coating (310C) is formed on at least a portion of the surface of the first plate (310). At this time, rather than applying the insulating coating (310C) to the entire surface of the first plate (310), masking may be performed on a portion of the surface to provide a first exposed portion (310E1) without the insulating coating (310C). The edge area of ​​the second plate (320) may be welded to the first exposed portion (310E1) of the first plate (310). There is no particular limitation on the welding method, and resistance welding or laser welding, etc. may be performed.

[0087] Meanwhile, in FIG. 8, the first exposed portion (310E1) is shown for convenience of explanation, but after welding between the first plate (310) and the second plate (320), an additional insulating coating may be applied to completely cover the first exposed portion (310E1) to cover the exposed portion of the first plate (310).

[0088] Additionally, an additional second exposed portion (310E2) may be provided on the edge of the lower surface of the first plate (310). When the second exposed portion (310E2) of the first plate (310) is welded to the side surface (220) of the pack frame (200), the first plate (310) may be joined to the pack frame (200). In other words, welding may also be applied to the joint between the pack cover (300) and the pack frame (200).

[0089]

[0090] Hereinafter, a method of joining between the first plate and the second plate according to other embodiments of the present invention will be described.

[0091] Figures 9 to 11 are cross-sectional views showing cross-sections of pack covers according to various embodiments of the present invention.

[0092] Referring to FIGS. 9 to 11, in the pack covers (300a, 300b, 300c) according to other embodiments of the present invention, the first plate (310) and the second plate (320) can be joined by a physical restraint. That is, the first plate (310) and the second plate (320) can be joined by a physical restraint rather than the welding method described in FIG. 8. In the case of joining by a physical restraint rather than a welding method, there is a concern that the sealing performance between the first plate (310) and the second plate (320) may be reduced. Therefore, in order to improve the sealing performance, a gasket may be interposed between the first plate (310) and the second plate (320) or a sealant may be applied. In FIGS. 9 to 11, a gasket (400) is shown interposed between the first plate (310) and the second plate (320) at the portion where the first plate (310) and the second plate (320) are joined.

[0093] The physical binding between the first plate (310) and the second plate (320) may be a bolting connection, a riveting connection, or a fitting connection.

[0094] First, referring to FIG. 9, the first plate (310) and the second plate (320) of the pack cover (300a) can be joined through bolting. Specifically, a bolt (510) can pass through a hole formed in each of the first plate (310) and the second plate (320) and be fastened with a nut (520). At this time, a gasket (400) can be interposed between the first plate (310) and the second plate (320), and the bolt (510) can pass through the hole of the gasket (400) and be fastened with the nut (520).

[0095] Referring to the following Figure 10, the first plate (310) and the second plate (320) of the pack cover (300b) can be joined through rivet fastening. Specifically, a rivet pin (600) having a rivet head (600H) formed at only one end is passed through a hole formed in each of the first plate (310) and the second plate (320). Thereafter, the other end of the rivet pin (600) is deformed to form another rivet head (600H). The first plate (310) and the second plate (320) can be fixed between the two rivet heads (600H). At this time, a gasket (400) can be interposed between the first plate (310) and the second plate (320), and the rivet pin (600) can pass through the hole of the gasket (400).

[0096] Referring to the following Figure 11, the first plate (310) and the second plate (320) of the pack cover (300c) can be joined through a fitting connection. Specifically, a bending portion (320B) may be provided at the edge of the second plate (320), and the first plate (310) and the second plate (320) may be joined to each other when the bending portion (320B) of the second plate (320) is fitted to the edge of the first plate (310). However, such a fitting connection is only one example, and there is no limitation on the fitting method between the first plate (310) and the second plate (320). Meanwhile, a gasket (400) may be interposed between the first plate (310) and the second plate (320).

[0097] 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.

[0098] The battery cells or battery modules according to the above-described embodiment can be mounted together with various control and protection systems such as a BMS (Battery Management System), a BDU (Battery Disconnect Unit), and a cooling system to form a battery pack.

[0099] The above 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, as well as ESS (Energy Storage Systems), but is not limited thereto. It can also be applied to various devices that can use secondary batteries.

[0100] 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.

[0101] Description of the symbol

[0102] 100: Battery module

[0103] 110: Battery cell

[0104] 110A: Battery cell stack

[0105] 120: Module Frame

[0106] 200: Pack Frame

[0107] 210: Bottom

[0108] 220: Side

[0109] 300: Pack Cover

[0110] 310: First Plate

[0111] 310C: Insulation coating

[0112] 320: Second Plate

Claims

1. Multiple battery cells; A pack frame having an open top, in which the battery cells are mounted or in which the battery cells are mounted in a state of being housed in a module frame; and A pack cover covering the above pack frame; The above pack cover includes a first plate and a second plate positioned on top of the first plate, A battery pack having an insulating coating formed on at least a portion of the surface of the first plate.

2. In paragraph 1, A battery pack wherein the first plate and the second plate include a metal material.

3. In paragraph 1, A battery pack in which an insulating coating is not formed on the surface of the second plate.

4. In paragraph 1, The second plate comprises a metal material, A battery pack in which the metal material of the second plate is exposed as is.

5. In paragraph 1, A battery pack in which, when the internal pressure of the pack frame increases, the first plate bends toward the direction where the second plate is located, so that the first plate and the second plate come into close contact with each other.

6. In paragraph 1, A battery pack wherein the second plate has a larger elastic modulus than the first plate.

7. In paragraph 1, A battery pack having a venting portion provided in the above pack frame.

8. In paragraph 1, A battery pack in which the second plate is welded to an exposed portion of the surface of the first plate where an insulating coating is not formed.

9. In paragraph 1, A battery pack in which the first plate and the second plate are joined by physical binding force.

10. In paragraph 9, The above physical binding force is a battery pack that is bolted, riveted or fitted.

11. In paragraph 9, A battery pack in which a gasket is interposed between the first plate and the second plate or a sealant is applied.

12. A device including a battery pack according to paragraph 1.

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