Battery module and battery pack including same

Abstract

A battery module according to an embodiment of the present invention includes a battery cell stack including a plurality of stacked battery cells, a module frame for accommodating the battery cell stack, and a phase-change material layer disposed between the battery cell stack and the module frame, the phase-change material layer including a phase-change material and having a mesh structure, and a vent hole formed in the module frame.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0142114, filed October 23, 2023, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module and a battery pack including the same, and more particularly to a battery module capable of guiding venting in a desired direction and a battery pack including the same. [Background technology]

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

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

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

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

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

[0008] In a battery pack consisting of multiple battery modules, the heat generated from the multiple battery cells can be combined in a small space, which can cause a rapid temperature rise. That is, a battery module in which multiple battery cells are stacked and a battery pack equipped with such a battery module can produce high output, but it is difficult to remove the heat generated from the battery cells during charging and discharging. If the heat from the battery cells is not properly dissipated, the battery cells will deteriorate quickly, their lifespan will be shortened, and there is a greater risk of explosion or fire.

[0009] Because multiple battery modules are placed close together to increase a vehicle's driving range, thermal runaway that occurs in one battery module can easily spread to adjacent battery modules, ultimately leading to the battery pack catching fire or exploding. Although thermal runaway can be prevented or delayed by placing insulation between battery cells, if a thermal runaway occurs in one battery cell within a closed space, it may also occur simultaneously in the battery cell stack that includes that battery cell.

[0010] In addition, when physical, thermal, or electrical damage occurs to a battery cell, including overcharging, the internal pressure of the battery cell increases and exceeds the battery cell's fusion strength limit. This can cause high-temperature gas and flames generated in the battery cell to be released outside the battery module, potentially affecting adjacent battery modules and other electrical components. This can lead to thermal propagation between adjacent battery modules, resulting in a chain reaction of fires within the battery pack.

[0011] Therefore, in order to prevent thermal propagation, it is necessary to develop venting technology that can guide high-temperature gas in a specific direction for each battery module, and technology that can delay thermal runaway between battery cells. Summary of the Invention [Problem to be solved by the invention]

[0012] The problem to be solved by the present invention is to provide a battery module and a battery pack including the same that can guide high-temperature gas and flame generated within the battery module in a specific direction and at the same time delay or prevent thermal runaway.

[0013] However, the problems to be solved by the embodiments of the present invention are not limited to the above-mentioned problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0014] A battery module according to an embodiment of the present invention includes a battery cell stack including a plurality of stacked battery cells, a module frame for accommodating the battery cell stack, and a phase-change material layer disposed between the battery cell stack and the module frame, the phase-change material layer including a phase-change material and having a mesh structure, and a vent hole formed in the module frame.

[0015] The phase change material layer may be located between an upper surface of the battery cell stack and a ceiling of the module frame.

[0016] The phase-change material layer may include an open portion that is an open region of the mesh structure and a block portion that is a closed region of the mesh structure.

[0017] At least one of the venting holes may be located corresponding to the opening of the phase-change material layer.

[0018] The phase change material layer may include a paraffin material.

[0019] The phase change material layer may have a hive-shaped, square-shaped, or diamond-shaped mesh structure.

[0020] The battery module may further include a bus bar frame covering an upper surface of the battery cell stack and a surface of the battery cell stack from which electrode leads protrude. A gas guide hole may be formed in a portion of the bus bar frame, and the portion of the bus bar frame in which the gas guide hole is formed faces a portion of the module frame in which the vent hole is formed.

[0021] The battery cell may include an electrode assembly and a battery case that houses the electrode assembly. A heat-insulating coating may be applied to the surface of the battery case, or the battery case may include a heat-insulating material.

[0022] The battery pack may further include a heat insulating case that encloses at least a portion of an outer surface of the battery cell, and the heat insulating case may have a vent formed therein.

[0023] The venting portion may be positioned to correspond to at least one of the venting holes of the module frame.

[0024] The battery pack according to an embodiment of the present invention includes the battery module, a pack frame in which the battery module is housed, and a pack cover covering the battery module housed in the pack frame, wherein a pack cover vent hole is formed in a portion of the pack cover corresponding to the vent hole.

[0025] The battery pack may further include a venting film covering an upper portion of the pack cover. [Effects of the Invention]

[0026] According to an embodiment of the present invention, a mesh-structured phase-change material layer is disposed between the battery cells and the module frame, and vent holes are formed in the module frame to allow high-temperature gases and flames to be discharged, thereby guiding the high-temperature gases and flames in a specific direction and minimizing thermal propagation between battery modules.

[0027] Additionally, when the thermal runaway temperature is reached, the phase change material layer melts, delaying or preventing thermal runaway and fire in the battery cell.

[0028] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a perspective view showing a battery module according to an embodiment of the present invention; [Figure 2] FIG. 2 is an exploded perspective view of the battery module of FIG. [Figure 3] 3 is a plan view showing one of the battery cells included in the battery module of FIG. 2. FIG. [Figure 4] FIG. 10 is an exploded perspective view showing a battery module according to another embodiment of the present invention. [Figure 5] 1A-1C are partial views illustrating phase change material layers according to various embodiments of the present invention. [Figure 6] 1A-1C are partial views illustrating phase change material layers according to various embodiments of the present invention. [Figure 7] 1A-1C are partial views illustrating phase change material layers according to various embodiments of the present invention. [Figure 8] FIG. 10 is a perspective view showing a battery cell stack according to another embodiment of the present invention. [Figure 9] 9 is an exploded perspective view showing the battery cells and heat insulating cases included in the battery cell stack of FIG. 8. FIG. [Figure 10] FIG. 10 is a perspective view showing the heat insulating case of FIG. 9. [Figure 11] 10A and 10B are cross-sectional views taken along the line CC' in FIG. 10, showing an embodiment of the present invention. [Figure 12] FIG. 10 is a perspective view showing a heat insulating case according to another embodiment of the present invention. [Figure 13] 1 is a partial perspective view showing a battery pack according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will now be described in detail with reference to the accompanying drawings, in which various embodiments of the present invention can be easily implemented by those skilled in the art. The present invention can be implemented in several different forms and is not limited to the examples described herein.

[0031] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0032] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are exaggerated to clearly show multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0033] Furthermore, when a layer, film, region, plate, or other part is said to be "on" or "above" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. Furthermore, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "above" or "above" the direction opposite to gravity.

[0034] Furthermore, throughout the specification, when a part "comprises" a certain element, it does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0035] Also, throughout the specification, "on a plane" means when the target part is viewed from above, and "on a cross section" means when the target part is cut vertically and viewed from the side.

[0036] Fig. 1 is a perspective view showing a battery module according to an embodiment of the present invention, Fig. 2 is an exploded perspective view of the battery module of Fig. 1, and Fig. 3 is a plan view showing one of the battery cells included in the battery module of Fig. 2.

[0037] 1 to 3, a battery module 100 according to an embodiment of the present invention includes a battery cell stack 120 in which a plurality of battery cells 110 are stacked, a module frame 200 that houses the battery cell stack 120, and a phase-change material layer 400a located between the battery cell stack 120 and the module frame 200.

[0038] The battery cell 110 according to this embodiment may be a battery cell of various types, such as a pouch-type battery cell, a prismatic battery cell, or a cylindrical battery cell. For example, as shown in Figures 2 and 3, the battery cell 110 according to this embodiment may be a pouch-type battery cell. While the following description will be given with reference to a pouch-type battery cell, the battery cell 110 according to this embodiment is not limited thereto, and various types of battery cells may be applied.

[0039] The battery cell 110 according to this embodiment may have a configuration in which an electrode assembly having electrode leads 111 protruding in one or both directions is housed in a pouch-shaped battery case 114. Such a battery cell 110 may be in the form of a rectangular sheet. The battery cell 110 may be formed by housing the electrode assembly in a battery case 114 made of a laminate sheet including a resin layer and a metal layer, and then bonding the outer periphery of the battery 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 example, the electrode leads 111 of the battery cell 110 may all protrude in one direction. One of the electrode leads 111 is a positive electrode lead, and the other is a negative electrode lead.

[0040] The battery cell 110 can be manufactured by bonding both ends 114a, 114b of the battery case 114 and one side 114c connecting them together while an electrode assembly (not shown) is housed in the battery case 114. That is, the battery cell 110 according to one embodiment of the present invention has a total of three sealing portions 114s, which are sealed by a method such as fusion, and the remaining side can be configured as a folding portion 115. That is, the battery cell 110 according to this embodiment can be a pouch-type secondary battery in which the electrode assembly is housed inside the battery case 114 and the outer periphery of the battery case 114 is sealed to form the sealing portion 114s. In FIG. 3, only the sealing portions 114s formed at both ends 114a and 114b of the battery case 114 are shown, and the sealing portion on the side facing the folding portion 115 is not shown, but the sealing portion on the side facing the folding portion 115 is folded to one side after sealing is completed to utilize space.

[0041] The laminate sheet battery case 114 may include an inner resin layer for sealing, a metal layer for preventing penetration of materials, and an outermost resin layer. Based on the electrode assembly inside the battery case 114, the inner resin layer may be located innermost, the outer resin layer may be located outermost, and the metal layer may be located between the inner and outer resin layers.

[0042] The outer resin layer may have excellent tensile strength and weather resistance relative to its thickness and electrical insulation 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 layer may be heat-sealed by applying heat and / or pressure with the electrode assembly inside. The inner resin layer may include cast polypropylene (CPP) or polypropylene (PP).

[0043] The battery case 114 is divided into two parts, and at least one of the two parts may have a recessed receiving portion in which an electrode assembly can be mounted. The inner resin layers of the two parts of the battery case 114 are joined together along the outer periphery of the receiving portion to form a sealing portion 114s. In this manner, the pouch case is sealed, and the battery cell 110, which is a pouch-type secondary battery, can be manufactured.

[0044] A plurality of battery cells 110 may be stacked so as to be electrically connected to each other. In particular, a plurality of battery cells 110 may be stacked in one direction in an upright state with one surface of the cell bodies 113 facing each other. For example, the battery cells 110 may be stacked in a direction parallel to the y-axis. As a result, the electrode leads 111 may protrude in a direction perpendicular to the direction in which the battery cells 110 are stacked. In a battery cell 110, one electrode lead 111 may protrude in the x-axis direction, and the other electrode lead 111 may protrude in the negative x-axis direction. If the electrode leads 111 protrude in only one direction, the electrode leads 111 may protrude in either the x-axis direction or the negative x-axis direction.

[0045] The battery cell stack 120 is housed in a module frame 200. The module frame 200 may be a metal frame with open sides. More specifically, both sides of the module frame 200 may be open in both directions in which the electrode leads 111 protrude from the battery cell stack 120. However, the module frame 200 shown in FIG. 2 is merely an exemplary structure, and there are no particular limitations on its shape as long as it can house the battery cell stack 120. The module frame 200 shown in FIG. 2 may include a ceiling 210, both side walls 220 and 230, and a bottom 240, which may cover the top, both side walls, and bottom of the battery cell stack 120, respectively. The module frame 200 may be a monoframe in which the ceiling 210, both side walls 220 and 230, and bottom 240 are integrated.

[0046] According to this embodiment, the module frame 200 has venting holes 200H formed therein. Specifically, the module frame 200 may have a plurality of venting holes 200H formed in the ceiling portion 210. The plurality of venting holes 200H may be arranged in a plurality of rows along the length direction of the battery cell stack 120, i.e., the x-axis direction in FIGS. 1 and 2. At least one of the plurality of rows may be arranged adjacent to one periphery of the ceiling portion 210 of the module frame 200.

[0047] By forming such venting holes 200H in the module frame 200, when a thermal runaway occurs inside the battery module 100, i.e., in the battery cell stack 120, the flow of gases and flames generated along with the thermal runaway can be guided upward, preventing the thermal propagation phenomenon in which the ignition spreads to other adjacent battery modules 100. In addition, the flow of gas guided to the top of the module frame 200 can be observed with the naked eye, thereby providing a solution for inducing a fire delay within the module. In particular, by arranging the venting holes 200H to distribute heat along the length of the battery cell stack 120, it is possible to guide the gas generated from the battery cells 110 across the entire length.

[0048] The vent holes 200H can be formed by applying a punching process to the ceiling portion 210 of the module frame 200. There are no particular limitations on the punching method, and methods such as drilling, punching, and pressing can be applied.

[0049] The battery module 100 according to this embodiment may include a bus bar frame 500 that covers the upper surface of the battery cell stack 120 and one or both surfaces of the battery cells 110 on which the electrode leads 111 protrude.

[0050] For example, the bus bar frame 500 may include an upper frame 510, a front frame 520, and a rear frame 530. The front frame 520 and the rear frame 530 are located on one side and the other side of the battery cell stack 120, respectively, to cover the battery cell stack 120 and to guide the connection between the battery cell stack 120 and an external device. Specifically, the front frame 520 and the rear frame 530 may be fitted with a bus bar 540, a terminal bus bar, a module connector, etc. In particular, the bus bar 540 may be fitted to the surface of each of the front frame 520 and the rear frame 530 opposite to the surface facing the battery cell stack 120.

[0051] The electrode lead 111 of the battery cell 110 passes through a slit formed in the front frame 520 and then bends to be joined to the bus bar 540 attached to the front frame 520. Meanwhile, the other electrode lead 111 of the battery cell 110 passes through a slit formed in the rear frame 530 and then bends to be joined to the bus bar 540 attached to the rear frame 530.

[0052] The bus bars 540 are for electrically connecting the battery cells 110, and may include a metal material and be joined to the electrode leads 111 of the battery cells 110 by welding. The bus bars 540 may connect the battery cells 110 constituting the battery cell stack 120 in series or parallel. In addition, the battery cells 110 may be electrically connected to external devices or circuits via terminal bus bars exposed to the outside of the battery module 100.

[0053] The front frame 520 and the rear frame 530 may include an electrically insulating material. The front frame 520 and the rear frame 530 may limit contact between the bus bar 540 and the battery cell 110, except for the portion where the bus bar 540 is joined to the electrode lead 111, thereby preventing the occurrence of a short circuit.

[0054] The upper frame 510 may be connected to each of the front frame 520 and the rear frame 530 and cover the upper surface of the battery cell stack 120. If the module frame 200 is a monoframe in which the ceiling 210, both side walls 220 and 230, and the bottom 240 are integrated, the battery cell stack 120 and the bus bar frame 500 may be inserted into one of the open sides of the module frame 200. In this manner, to prevent the upper surface of the battery cell stack 120 from being damaged by the module frame 200 during the insertion process, the bus bar frame 500 may be provided with an upper frame 510 that covers the upper surface of the battery cell stack 120.

[0055] According to this embodiment, a gas guide hole 500H may be formed in a portion of the bus bar frame 500, and the portion of the bus bar frame 500 where the gas guide hole 500H is formed faces the portion of the module frame 200 where the venting holes 200H are formed. Specifically, the gas guide hole 500H may be formed in the upper frame 510 of the bus bar frame 500 so as to face the plurality of venting holes 200H formed in the ceiling portion 210 of the module frame 200. The gas guide hole 500H of the bus bar frame 500, together with the venting holes 200H of the module frame 200, can guide gas and flames generated from the battery cell stack 120 to the upper side of the battery module. This can prevent thermal propagation, which is the propagation of fire to other adjacent battery modules 100.

[0056] Meanwhile, the battery module 100 according to this embodiment may include end plates 300 covering both open sides of the module frame 200. One of the end plates 300 may be joined to the module frame 200 while covering the front frame 520, and the other of the end plates 300 may be joined to the module frame 200 while covering the rear frame 530. The front frame 520 may be positioned between one of the end plates 300 and the battery cell stack 120, and the rear frame 530 may be positioned between the other of the end plates 300 and the battery cell stack 120.

[0057] The end plates 300 may be positioned to cover both sides of the battery cell stack 120 in the direction in which the electrode leads 111 protrude. The end plates 300 may protect the battery cell stack 120 and various electrical components from external impacts and, to that end, must have a certain strength and may be made of a metal such as aluminum. Each of the first end plates 300 may be joined to a corresponding corner of the module frame 200 by welding or other methods. Although not specifically shown, insulating covers (not shown) for electrical insulation may be positioned between one end plate 300 and the front frame 520 and between the other end plate 300 and the rear frame 530.

[0058] FIG. 4 is an exploded perspective view showing a battery module according to another embodiment of the present invention.

[0059] 4, a battery module 100 according to another embodiment of the present invention may include a battery cell stack 120, a module frame 200, end plates 300, and a bus bar frame 500. The battery cell stack 120 and the end plates 300 have the same configurations as those described above with reference to FIGS. 1 and 2, and therefore further description thereof will be omitted.

[0060] The module frame 200 according to this embodiment may include an upper cover 200a and a U-shaped frame 200b. The battery cell stack 120 may be housed in an internal space formed by the upper cover 200a and the U-shaped frame 200b. The upper cover 200a may cover the upper surface of the battery cell stack 120. The U-shaped frame 200b may include side walls 220, 230 and a bottom 240. The side walls 220, 230 of the U-shaped frame 200b may cover both sides of the battery cell stack 120, and the bottom 240 of the U-shaped frame 200b may cover the lower surface of the battery cell stack 120.

[0061] The module frame 200 may be completed by welding the side walls 220 and 230 of the U-shaped frame 200b to the upper cover 200a. That is, the upper cover 200a joined to the U-shaped frame 200b may correspond to the ceiling of the module frame 200. The venting holes 200H according to this embodiment may be formed in the ceiling of the module frame 200, i.e., the upper cover 200a. The description of the venting holes 200H will be omitted as it is the same as that described above.

[0062] The bus bar frame 500 according to this embodiment may include a front frame 520 and a rear frame 530. The bus bars 540 described above may be attached to the front frame 520 and the rear frame 530. However, unlike the bus bar frame shown in FIGS. 1 and 2, the bus bar frame 500 according to this embodiment may not include an upper frame. After the battery cell stack 120 and the bus bar frame 500 are inserted through the open top of the U-shaped frame 200b, the U-shaped frame 200b and the upper cover 200a may be joined together. That is, since there is no risk of damage to the top surface of the battery cell stack 120 during the process of inserting the battery cell stack 120 into the module frame 200, the upper frame can be omitted from the bus bar frame 500, thereby reducing the weight and vertical space of the battery module 100 according to this embodiment.

[0063] Hereinafter, the phase change material layer 400a according to an embodiment of the present invention will be described in detail.

[0064] 5 to 7 are partial views illustrating phase-change material layers according to various embodiments of the present invention.

[0065] 2, 4, and 5, the phase change material layer 400a according to this embodiment is located between the battery cell stack 120 and the module frame 200, as described above, includes a phase change material (PCM), and has a mesh structure. In particular, the phase change material layer 400a may be located between the upper surface of the battery cell stack 120 and the ceiling of the module frame 200. In the battery module 100 of FIG. 2, the phase change material layer 400a may be located between the upper surface of the battery cell stack 120 and the upper frame 510 of the bus bar frame 500. In the battery module 100 of FIG. 4, since the bus bar frame 500 does not have an upper frame, the phase change material layer 400a may be located between the upper surface of the battery cell stack 120 and the ceiling of the module frame 200, i.e., the upper cover 200a.

[0066] Because the phase-change material layer 400a according to this embodiment has a mesh structure, it can guide the flow of gas and flames that are guided upward when a thermal runaway phenomenon occurs in the battery cell stack 120. That is, the gas and flames generated in the battery cell stack 120 can pass through the mesh-structured phase-change material layer 400a and then be discharged to the outside through the venting holes 200H of the module frame 200. In the battery module 100 of FIG. 2, the gas and flames can be discharged to the outside by sequentially passing through the mesh-structured phase-change material layer 400a, the gas guide holes 500H of the bus bar frame 500, and the venting holes 200H of the module frame 200.

[0067] The phase change material layer 400a includes a phase change material (PCM). In particular, the phase change material layer 400a according to this embodiment may be a mesh-structured sheet of phase change material. The phase change material layer 400a including the phase change material (PCM) melts when the temperature reaches a thermal runaway temperature during thermal runaway of the battery cell stack 120, thereby delaying or preventing thermal runaway and ignition of the battery cells 110. The phase change material layer 400a can perform a type of fire extinguishing function for the battery cells 110. That is, the phase change material layer 400a according to this embodiment can guide gases and flames generated during a thermal runaway phenomenon of the battery cell stack 120 to be discharged to the vent holes 200H of the module frame 200, and at the same time, can function as a fire extinguishing member that directly extinguishes thermal runaway and ignition of the battery cells 110. The phase change material layer 400a may include paraffin as the phase change material.

[0068] Furthermore, when the phase-change material layer 400a has a mesh structure, the phase-change material layer 400a can be formed to a small thickness, and therefore can be easily inserted into a narrow gap between the battery cell stack 120 and the ceiling portion 210 of the module frame 200 or a narrow gap between the battery cell stack 120 and the upper frame 510 of the bus bar frame 500. Furthermore, when the phase-change material layer 400a has a mesh structure, when the battery module 100 or a battery pack structure including the battery module 100 collapses due to gas or pressure inside the battery module 100, the mesh structure of the phase-change material layer 400a can be expected to partially support the battery module 100 and slow down the rate of collapse.

[0069] The phase-change material layer 400a according to this embodiment may include open portions 410, which are open regions of the mesh structure, and block portions 420, which are closed regions of the mesh structure. When fabricating a mesh structure using a phase-change material such as paraffin, some regions of the mesh structure may be filled with the phase-change material to form the block portions 420, which are closed regions. The open portions 410 may also be left unfilled with the phase-change material. By providing some regions of the mesh-structured phase-change material layer 400a as open portions 410 and other regions as block portions 420, gas discharge in a desired direction, i.e., directional venting, can be more effectively achieved. That is, the designer can form the block portions 420 and open portions 410 in desired areas of the phase-change material layer 400a, thereby easily designing the gas discharge area and the degree of gas discharge in the gas discharge area.

[0070] For example, at least one of the venting holes 200H of the module frame 200 may be positioned to correspond to the opening 410 of the phase-change material layer 400a. "At least one of the venting holes 200H corresponding to the opening 410" means that at least one of the venting holes 200H and the opening 410 overlap each other when viewed from above. Also, "viewing the battery module 100 from above" means viewing the battery module 100 in a direction perpendicular to the ground. That is, "viewing the battery module 100 from above" means viewing the battery module 100 in the -z-axis direction on the xy plane in FIG. 1, 2, or 4.

[0071] Because the venting holes 200H and the openings 410 are positioned to overlap each other, directional venting can be more effectively performed, guiding flames or gases generated during thermal runaway of the battery cell stack 120 to the venting holes 200H. That is, the openings 410 of the phase-change material layers 400a, which are provided to correspond to the venting holes 200H, can guide the gases or flames to the venting holes 200H and allow them to be discharged through the venting holes 200H.

[0072] As described above, the phase-change material layer 400a melts when it reaches a thermal runaway temperature and functions as a fire extinguishing member that directly extinguishes thermal runaway and fire in the battery cell 110. However, to effectively perform the fire extinguishing function, the phase-change material must be provided in a predetermined volume. That is, if the phase-change material is provided only in a mesh structure, the amount of the phase-change material itself may be insufficient and the fire extinguishing function may not be properly performed. By forming the block portion 420, the phase-change material layer 400a can be provided with a predetermined volume of the phase-change material, thereby effectively performing the fire extinguishing function.

[0073] In summary, by forming the open portion 410 and the block portion 420 in the phase-change material layer 400a according to this embodiment, gas can be effectively discharged in the desired direction, i.e., directional venting, and at the same time, direct fire extinguishing can be achieved against thermal runaway and fire in the battery cell 110.

[0074] 5 to 7, the phase-change material layers 400a, 400b, and 400c according to the present invention may have a hive-shaped, square-shaped, or diamond-shaped mesh structure. FIGS. 2, 4, and 5 show a phase-change material layer 400a having a hive-shaped mesh structure. FIG. 6 shows a phase-change material layer 400b having a square-shaped mesh structure, and FIG. 7 shows a phase-change material layer 400c having a diamond-shaped mesh structure. Each of the phase-change material layers 400a, 400b, and 400c may have the open portions 410 and block portions 420 described above. That is, as long as the phase-change material layers 400a, 400b, and 400c according to the present invention have a mesh structure, there are no particular limitations on the specific shape of the mesh structure. However, a hive-shaped mesh structure, which is structurally stable, is most preferred in order for the mesh-structured phase-change material layer to perform its supporting function for the battery module.

[0075] Meanwhile, referring again to FIG. 3 , the battery cell 110 according to this embodiment may include an electrode assembly (not shown) and a battery case 114 that houses the electrode assembly, as described above. In this case, the surface of the battery case 114 may be coated with a thermal insulating coating, or the battery case 114 may contain a thermal insulating material. While a separate insulating material may be disposed between the battery cells 110 of the battery cell stack 120, if a thermal runaway phenomenon occurs in a battery cell 110 in a closed space, the entire battery cell stack may also experience thermal runaway, and a separate insulating material may not be sufficient to protect against this. In contrast, in this embodiment, a thermal insulating coating process is performed to coat the surface of the battery case 114 of the battery cell 110 with a material containing a thermal insulating material, or the battery case 114 itself may contain a thermal insulating material, thereby protecting most surfaces of the battery cell 110 from thermal runaway. There are no particular limitations on the material used as the insulating material as long as it can provide thermal insulation.

[0076] Fig. 8 is a perspective view showing a battery cell stack according to another embodiment of the present invention. Fig. 9 is an exploded perspective view showing battery cells and a heat insulating case included in the battery cell stack of Fig. 8. Fig. 10 is a perspective view showing the heat insulating case of Fig. 9.

[0077] 8 to 10, in a battery cell stack 120 according to another embodiment of the present invention, the outer surface of each battery cell 110 may be enclosed in an insulating case 130. The insulating case 130 may enclose at least a portion of the outer surface of the battery cell 110 and may include an insulating material.

[0078] The heat insulating case 130 may include a top portion 131 and side portions 132 and 133. The top portion 131 may cover an upper portion of the battery cell 110, and the side portions 132 and 133 may cover both side surfaces of the battery cell 110, respectively. One surface of the side portions 132 and 133 and one surface of the top portion 131 may be perpendicular, and the side portions 132 and 133 may extend downward from opposite sides of the top portion 131, respectively. The heat insulating case 130 according to this embodiment may have an open bottom. That is, when the heat insulating case 130 is cut along one plane, the heat insulating case 130 may have an "n" shape. The heat insulating case 130 according to this embodiment may be configured to enclose at least a portion of three of the remaining four sides of the six-sided battery cell 110, excluding two sides on which the electrode leads 111 are formed.

[0079] The heat insulating case 130 can not only delay thermal runaway but also complement the rigidity of the battery cells 110, thereby allowing the battery cells 110 to maintain an upright state. The heat insulating case 130 can support the battery cells 110 by covering at least a portion of the battery cells 110, and can stably maintain the stacked state of the battery cells 110 arranged upright in one direction. More specifically, the side portions 132 and 133 of the heat insulating case 130 support the side surfaces of the battery cells 110, allowing the battery cells 110 to maintain an upright state.

[0080] 11(a) and 11(b) are cross-sectional views taken along the line CC' in FIG. 10, showing an embodiment of the present invention.

[0081] 9 to 11, a venting portion 130V may be formed in the heat insulating case 130. In particular, the venting portion 130V may be formed on the top surface 131 of the heat insulating case 130, and there are no particular restrictions on the number or area thereof. The heat insulating case 130 is box-shaped and contains a heat insulating material, and can prevent thermal runaway generated in a battery cell 110 inside it from spreading to adjacent battery cells 110. There are no particular restrictions on the material used for the heat insulating material contained in the heat insulating case 130, as long as it can perform heat insulating functions.

[0082] When thermal runaway occurs in at least one battery cell 110 inside the thermal insulation case 130, generating high-temperature gas and flame, the venting portion 130V formed in the thermal insulation case 130 functions as a passage for discharging the high-temperature gas and flame. As long as the gas and flame can be efficiently discharged, there is no particular limit to the number and area of ​​the venting portions 130V provided in one thermal insulation case 130. For example, as shown in Figures 8 and 9, three venting portions 130V may be formed on the top surface 131 of the thermal insulation case 130, and the area of ​​the venting portion 130V formed in the center may be slightly larger than the areas of the other venting portions 130V.

[0083] In the past, when a fire occurred in the battery cell 110, gas and sparks moved toward the electrode lead 111, which caused a problem of additional thermal runaway. However, in this embodiment, the vent 130V is formed in the heat insulating case 130, thereby minimizing the movement of gas and sparks toward the electrode lead 111. The gas exhaust path through the vent 130V can be separated from the electrode lead 111, which prevents the electrode lead 111 and the electrical components connected thereto from being damaged by gas, sparks, or flames.

[0084] In addition, the venting portion 130V may be positioned to correspond to at least one of the venting holes 200H of the module frame 200. The positioning of the venting portion 130V to correspond to the venting hole 200H of the module frame 200 means that the venting portion 130V and at least one of the venting holes 200H are positioned so that they overlap each other when the battery module 100 is viewed from above.

[0085] By providing the venting portion 130V in the heat insulating case 130, high-temperature gas and flame generated from the battery cells 110 can be induced to pass through the venting portion 130V and be discharged through the venting holes 200H of the module frame 200. That is, the high-temperature gas and flame generated from the battery cells 110 can be discharged to the outside by sequentially passing through the venting portion 130V, the mesh-structured phase-change material layer 400a, and the venting holes 200H.

[0086] Meanwhile, as shown in Fig. 11(a), venting portion 130Va according to one embodiment of the present invention may be a hole formed by partially penetrating top surface 131 of thermal insulation case 130. Alternatively, as shown in Fig. 11(b), venting portion 130Vb according to another embodiment of the present invention may be a portion of top surface 131 that is relatively weaker in rigidity than the adjacent portion, such that the portion ruptures when a force or heat exceeding a certain pressure is applied. In this embodiment, when high-temperature gas or flame erupts from battery cell 110 enclosed in thermal insulation case 130, the high-temperature gas or flame can be exhausted through venting portion 130V.

[0087] FIG. 12 is a perspective view showing a heat insulating case according to another embodiment of the present invention.

[0088] 12, an insulating case 130' according to another embodiment of the present invention may include an upper surface 131, side surfaces 132 and 133, and a lower surface 134. The upper surface 131 may cover an upper portion of the battery cell 110, the side surfaces 132 and 133 may cover both side surfaces of the battery cell 110, and the lower surface 134 may cover a lower portion of the battery cell 110. When the insulating case 130' is cut along a single plane, the insulating case 130' may have a square shape. The insulating case 130' according to this embodiment may be configured to enclose at least a portion of the remaining four surfaces of the six-sided battery cell 110, excluding the two surfaces on which the electrode leads 111 are formed.

[0089] Meanwhile, venting portions 130V may be formed in the heat insulating case 130'. In particular, the venting portions 130V may be formed on the upper surface 131 of the heat insulating case 130', and there are no particular limitations on the number or area of ​​the venting portions 130V. A detailed description of the venting portions 130V will be omitted as it is the same as that described above.

[0090] A battery pack according to an embodiment of the present invention will now be described.

[0091] FIG. 13 is a partial perspective view showing a battery pack according to one embodiment of the present invention.

[0092] Referring to Figures 1, 2 and 13 together, a battery pack according to one embodiment of the present invention includes a battery module 100, a pack frame 1100 in which the battery module 100 is housed, and a pack cover 1200 that covers the battery module 100 housed in the pack frame 1100.

[0093] The pack frame 1100 may be a structure having an internal space 1100S and an open top, and the battery module 100 may be housed in the internal space 1100S of the pack frame 1100. One or more battery modules 100 may be housed in the pack frame 1100.

[0094] The pack cover 1200 is a structure that covers the open top of the pack frame 1100. Pack cover venting holes 1200H may be formed in the pack cover 1200 at portions corresponding to the venting holes 200H of the module frame 200. High-temperature gas or flames generated due to a thermal runaway phenomenon of the battery module 100 can be discharged through the venting holes 200H of the module frame 200 and then discharged to the outside of the battery pack through the pack cover venting holes 1200H formed in the pack cover 1200.

[0095] Meanwhile, the battery pack according to this embodiment may further include a venting film 1300 covering an upper portion of the pack cover 1200. The venting film 1300 is a member provided to guide venting to a certain section without interfering with the operation of the vehicle when the battery pack is installed in the vehicle. For example, the venting film 1300 may be a mesh-like member. However, the venting film 1300 is provided as needed, and if another venting device can be used instead, the battery pack may not include such a venting film.

[0096] 2 and 4, the battery module 100 according to this embodiment may include a thermally conductive resin layer 700 located between the lower surface of the battery cell stack 120 and the bottom 240 of the module frame 200. The thermally conductive resin layer 700 is formed by injecting a thermally conductive resin and may include a thermally conductive adhesive material. Specifically, the thermally conductive resin may be formed by injecting a flowable thermally conductive resin and then solidifying the thermally conductive resin while in contact with the battery cell stack 120. That is, the thermally conductive resin layer 700 may transfer heat generated from the battery cell stack 120 to the bottom of the battery module 100 and also fix the battery cell stack 120 within the battery module 100.

[0097] The battery module 100 may also include compression pads 800 located on the outermost side of the battery cell stack 120. The compression pads 800 may also be disposed between the battery cells 110. Such compression pads 800 may be disposed to absorb the expansion of the battery cells 110 during charging and discharging.

[0098] In this embodiment, terms indicating directions such as front, back, left, right, up, and down are used, but these terms are used for convenience of explanation and may differ depending on the position of the target object, the position of the observer, etc.

[0099] One or more battery modules according to the above-described embodiments may 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.

[0100] The battery module or battery pack can be applied to various devices, specifically, but not limited to, transportation means such as electric bicycles, electric vehicles, and hybrid vehicles, and ESS (Energy Storage Systems), and can be applied to various devices that can use secondary batteries.

[0101] 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 claims below also fall within the scope of the present invention. [Explanation of symbols]

[0102] 100 Battery Module 110 battery cells 120 Battery cell stack 200 Module Frame 200H Venting Hole 300 End Plate 400a, 400b, 400c Phase change material layer 410 Open Section 420 Block 500 Busbar Frame

Claims

1. a battery cell stack in which a plurality of battery cells are stacked; a module frame that houses the battery cell stack; and a phase change material layer disposed between the battery cell stack and the module frame; the phase-change material layer includes a phase-change material and has a mesh structure; The battery module has a vent hole formed in the module frame.

2. The battery module according to claim 1 , wherein the phase-change material layer is located between the upper surface of the battery cell stack and a ceiling of the module frame.

3. The battery module of claim 1 or 2, wherein the phase-change material layer includes an open portion that is an open region of the mesh structure and a block portion that is a closed region of the mesh structure.

4. The battery module of claim 3 , wherein at least one of the vent holes is positioned corresponding to the opening of the phase change material layer.

5. The battery module according to claim 1 or 2, wherein the phase change material layer includes a paraffin material.

6. 3. The battery module of claim 1, wherein the phase change material layer has a mesh structure of a hive, square, or diamond shape.

7. a bus bar frame covering an upper surface of the battery cell stack and one surface of the battery cell in a direction in which the electrode leads of the battery cells protrude, 3. The battery module of claim 1, wherein a gas guide hole is formed in a portion of the bus bar frame, and the portion of the bus bar frame in which the gas guide hole is formed faces a portion of the module frame in which the vent hole is formed.

8. the battery cell includes an electrode assembly and a battery case that houses the electrode assembly; 3. The battery module according to claim 1, wherein a surface of the battery case is coated with a heat insulating coating, or the battery case contains a heat insulating material.

9. a heat insulating case that encases at least a portion of an outer surface of the battery cell; The battery module according to claim 1 or 2, wherein the heat insulating case is formed with a vent.

10. The battery module of claim 9 , wherein the venting portion is positioned to correspond to at least one of the venting holes of the module frame.

11. The battery module according to claim 1 or 2, a pack frame in which the battery module is housed; and a pack cover that covers the battery module housed in the pack frame, The battery pack has a pack cover vent hole formed in a portion of the pack cover corresponding to the vent hole.

12. The battery pack according to claim 11 , further comprising a venting film covering an upper portion of the pack cover.

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