Battery module and battery pack including same

Abstract

A battery module according to one embodiment of the present invention includes a battery cell assembly formed by stacking a plurality of battery cells, a module frame that houses the battery cell assembly and includes a bottom portion, and a phase-change material layer disposed at a lower portion of the battery cell assembly, wherein the phase-change material layer is melted and removed at a portion of the plurality of battery cells corresponding to a battery cell in which a high temperature phenomenon has occurred, and the bottom portion is opened at the portion where the phase-change material layer has been removed, thereby allowing the battery cell in which the high temperature phenomenon has occurred to be discharged to the outside.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0168581, filed November 28, 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 and a battery pack including the same that can effectively deal with a temperature rise in one battery cell within the battery module. [Background technology]

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

[0004] Currently commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Of these, lithium secondary batteries are attracting attention due to their advantages over nickel-based secondary batteries, such as almost no memory effect, freedom in charging and discharging, a very 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] Recently, secondary batteries have been widely used not only in small devices such as portable electronic devices but also in medium- to large-sized devices such as automobiles and power storage devices. For application to medium- to large-sized devices, multiple secondary batteries may be electrically connected to increase capacity and output. At this time, pouch-type secondary batteries are becoming more widely used due to their advantages such as easy stacking and light weight.

[0008] While secondary batteries used in small devices typically have two to three battery cells, secondary batteries used in medium- to large-sized devices such as automobiles typically use battery modules in which multiple battery cells are electrically connected. These battery modules improve capacity and output by connecting multiple battery cells in series or parallel to form a battery cell assembly. One or more battery modules may also 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.

[0009] Battery modules and battery packs formed with a large number of closely packed battery cells can be vulnerable to fire. For example, if an abnormally high temperature occurs in one battery cell and ignites, the heat can be transferred to other adjacent battery cells, easily spreading into a larger fire. Therefore, even if a fire breaks out in only a few battery cells, the fire can spread beyond the battery module or battery pack to the entire battery rack or power storage device, increasing the risk of loss of life and causing enormous economic losses. Therefore, it is necessary to quickly and accurately extinguish the fire before all battery modules in the battery rack or power storage device are burned or damaged.

[0010] Various technologies have been proposed to extinguish fires in devices that include battery modules, such as power storage devices. However, no effective fire extinguishing technology has yet been established. In particular, fires that occur in lithium-ion batteries included in battery modules are difficult to extinguish using conventional fire extinguishing agents, and selective extinguishing of a fire in a battery module where multiple battery modules are closely spaced remains a challenge. Therefore, there is a need for a solution that can quickly separate a battery cell that has experienced a high temperature phenomenon from other cells to effectively prevent the fire from spreading to a large-scale fire. Summary of the Invention [Problem to be solved by the invention]

[0011] The problem to be solved by the present invention is to provide a battery module and a battery pack including the same that can effectively extinguish a fire even if it occurs in some battery cells, thereby preventing the fire from spreading to a larger scale.

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

[0013] A battery module according to one embodiment of the present invention includes a battery cell assembly formed by stacking a plurality of battery cells, a module frame that houses the battery cell assembly and includes a bottom portion, and a phase-change material layer disposed at the bottom of the battery cell assembly, wherein the phase-change material layer is melted and removed at a portion of the plurality of battery cells corresponding to a battery cell in which a high temperature phenomenon has occurred, and the bottom portion is opened at the portion where the phase-change material layer has been removed, allowing the battery cell in which the high temperature phenomenon has occurred to be discharged to the outside.

[0014] An injection nozzle for injecting nitrogen gas may be formed on the upper surface of the module frame.

[0015] As nitrogen is injected through the injection nozzle, the battery cell where the high temperature phenomenon occurs may be pressurized downward and discharged.

[0016] The bottom part can be broken and opened when a battery cell in which a high temperature phenomenon occurs is pressed downward.

[0017] Lubricating oil may be applied between the plurality of battery cells.

[0018] The battery pack may further include at least one spring disposed above each of the plurality of battery cells to press the battery cell downward.

[0019] After the battery cell in which the high temperature phenomenon occurred is ejected, the spring may fill at least a portion of the space in which the battery cell in which the high temperature phenomenon occurred was disposed.

[0020] The bottom portion may include a plurality of opening / closing portions corresponding to the respective battery cells.

[0021] The opening / closing part may be configured to be opened by heat or pressure applied by the battery cell in which the high temperature phenomenon occurs.

[0022] A battery pack according to an embodiment of the present invention includes the battery module. [Effects of the Invention]

[0023] According to an embodiment of the present invention, it is possible to provide a battery module and a battery pack including the same that can prevent a fire from occurring by quickly separating a battery cell in which a high temperature phenomenon has occurred from other battery cells before a fire occurs.

[0024] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned above will be clearly understood by those skilled in the art from the description of the claims. [Brief explanation of the drawings]

[0025] [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. 1. [Figure 3] 2 is a cross-sectional view taken along line AA' in FIG. 1; [Figure 4] 4 is a diagram showing a state in which a cell in which a high temperature phenomenon occurs in FIG. 3 is discharged. [Figure 5] 10 is a view illustrating a state in which a cell in which a high temperature phenomenon occurs is removed from a battery module according to another embodiment of the present invention. [Figure 6] 10 is a view illustrating a state in which a cell in which a high temperature phenomenon occurs is removed from a battery module according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention may be embodied in various different forms and is not limited to the embodiments set forth herein.

[0027] In order to clearly explain the present invention, parts unnecessary for the explanation are omitted, and the same reference numerals are used throughout the specification to refer to the same or similar components.

[0028] 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.

[0029] Furthermore, when a layer, film, region, plate, or other part is said to be "on" another part, this does not only mean that it is "directly on" that other part, but also includes cases where there are other parts in between. Conversely, when a part is said to be "directly on" another part, it means that there are no other parts in between. Furthermore, being "on" a reference part means being located above or below the reference part, and does not necessarily mean being "on" in the opposite direction of gravity.

[0030] Furthermore, throughout the specification, when a part is said to "comprise" a certain element, this does not mean that it excludes other elements and may further include other elements, unless specifically stated to the contrary.

[0031] Also, throughout the specification, "on a plane" means when the subject part is viewed from above, and "on a cross section" means when the subject part is cut vertically and viewed from the side.

[0032] A battery module according to one embodiment of the present invention will now be described with reference to FIGS.

[0033] FIG. 1 is a perspective view showing a battery module according to one embodiment of the present invention, FIG. 2 is an exploded perspective view of the battery module of FIG. 1, FIG. 3 is a view showing a cross section A-A' of FIG. 1, and FIG. 4 is a view showing a state in which a cell in FIG. 3 where a high temperature phenomenon has occurred is removed.

[0034] 1 to 3, a battery module 100 according to an embodiment of the present invention includes a battery cell assembly 120 in which a plurality of battery cells 110 are stacked in one direction, and a module frame 200 that houses the battery cell assembly 120 therein.

[0035] First, the battery cell 110 may be a pouch-type battery cell, but is not limited thereto and various other types of battery cells may be used. A plurality of battery cells are stacked to be electrically connected to each other to form a battery cell assembly 120. For example, as shown in FIG. 2, a plurality of battery cells 110 may be stacked in a direction parallel to the y-axis. Accordingly, the electrode leads 111 may protrude in the x-axis direction and the -x-axis direction, respectively. Bus bar frames (not shown) may be located on both sides of the battery cell assembly 120 in the direction in which the electrode leads protrude. However, this is an exemplary arrangement, and the position of the bus bar frame is not limited thereto and may be located to cover the other side of the battery cell assembly 120. In other words, the position of the bus bar frame may be changed appropriately depending on the protruding direction of the electrode leads 111 as long as it is a position that allows electrical connection between the electrode leads 111 and the bus bar, but is not particularly limited thereto.

[0036] Such battery cells 110 are stacked in one direction to form a battery cell assembly 120. Specifically, the battery cells 110 may be stacked in the one direction while standing upright so that one side of each battery cell 110 faces each other.

[0037] The module frame 200 according to this embodiment is a member that houses the battery cell assembly 120 therein and includes two side portions 210 and 220, a top portion 230, and a bottom portion 240. One side (x-axis direction) and the other side (-x-axis direction) of the module frame 200 are open, and the battery cell assembly 120 can be housed through the open side or the other side. The module frame 200 shown in FIG. 2 may be a monoframe in which the two side portions 210 and 220, the top portion 230, and the bottom portion 240 are integrated. That is, the module frame 200 may be manufactured by extrusion molding, in which the two side portions 210 and 220, the top portion 230, and the bottom portion 240 are integrated. Although not specifically shown, in other embodiments of the present invention, a module frame in which a U-shaped frame and an upper plate are welded to each other or a module frame in which an inverted U-shaped frame and a lower plate are welded to each other may also be used. Various frame shapes are applicable, without being particularly limited. In terms of the stacking direction of the module frame 200 and the battery cells 110, the battery cells 110 may be stacked from one side surface 210 to the other side surface 220 with the one side surface of the battery cell 110 parallel to one side surface of the side surfaces 210 and 220 of the module frame 200.

[0038] Meanwhile, the battery module 100 according to this embodiment may further include end plates 300 located on the one and other open sides of the module frame 200. The end plates 300 may be located to cover the battery cell assemblies 120 on the one and other open sides of the module frame 200. Corners of each end plate 300 may be joined to corresponding corners of the module frame 200 by welding. The end plates 300 may include a metal material having a predetermined strength and may protect the battery cell assemblies 120 and other electrical components from external impacts.

[0039] The battery module 100 may further include a phase change material layer 400 positioned between the battery cell assembly 120 and the bottom portion 240 of the module frame 200. The phase change material layer 400 may include a phase change material (PCM). A phase change material is a material that exhibits repeated heat storage and heat generation characteristics, absorbing heat when the ambient temperature rises and crystallizing and releasing heat when the ambient temperature drops. In the normal state of the battery cells 110, it absorbs heat from the battery cells 110 to provide a cooling effect. In addition, the phase change material included in the phase change material layer 400 may melt at a specific temperature, particularly a high temperature close to the ignition temperature of the battery cells 110, thereby eliminating the portion supporting the battery cells 110 that has experienced a high temperature phenomenon. Examples of such phase change materials include paraffin, various salt hydrates, and polyethylene glycol (PSG). Furthermore, the phase-change material layer 400 may include a phase-change material alone or may be mixed with various materials for ease of handling during processing, but is not particularly limited thereto.

[0040] When a high temperature occurs in one of the plurality of battery cells 110, the phase-change material layer 400 can be eliminated by absorbing the heat generated in the battery cell and melting. That is, as shown in FIG. 4, the portion corresponding to the battery cell 110' where the high temperature occurs is melted and eliminated, and then the bottom portion 240 of the corresponding portion is opened, allowing the battery cell 110' where the high temperature occurs to be discharged to the outside. The process of the battery cell 110' where the high temperature occurs to be discharged to the outside can be performed by gravity or by the pressure of venting gas generated from the battery cell 110' where the high temperature occurs, causing it to fall to the outside. At this time, the bottom portion 240 below the phase-change material layer 400 can be broken and released due to the high temperature and pressure.

[0041] Alternatively, the battery cell 110' experiencing a high temperature can be manually ejected before complete ignition occurs. To this end, the upper surface 230 of the module frame 200 may further include an injection nozzle 500 for injecting nitrogen. The injection nozzle 500 is connected to a nitrogen storage container (not shown) separately provided outside the battery module 100 and is opened when a specific temperature is reached to inject nitrogen into the battery module 100, thereby increasing the pressure inside the battery module 100. This allows the battery cell 110 to be pressurized from above. During this process, the phase-change material layer 400 underneath the battery cell 110' experiencing a high temperature is erased by the high temperature and pressure, allowing only the battery cell 110' experiencing a high temperature to be pushed downward and ejected. Therefore, the battery cell 110' experiencing a high temperature can be ejected before ignition occurs, preventing ignition.

[0042] Meanwhile, to facilitate smooth ejection of the battery cell 110′ in which a high temperature phenomenon has occurred, lubricating oil may be applied between the battery cells 110. This reduces friction between adjacent battery cells 110, thereby achieving the effect of more quickly ejecting the battery cell 110′ in which a high temperature phenomenon has occurred to the outside.

[0043] As described above, according to one embodiment of the present invention, by including the phase-change material layer 400 at the bottom of the battery cell assembly 120, when a high temperature occurs in a battery cell 110′, the phase-change material layer 400 melts and disappears, allowing the battery cell 110′ in which the high temperature occurs to be quickly discharged to the outside (bottom), and thereby separating the battery cell 110′ in which the high temperature occurs from the other battery cells 110, thereby preventing the spread of a fire and preventing the occurrence of a fire, thereby improving the safety of the battery module 100. Meanwhile, in this embodiment, a case in which the battery cell assembly 120 is housed in the module frame 200 and is discharged to the outside of the module frame 200 has been described as an example, but the present invention is not limited thereto and may be applied to any structure in which a plurality of battery cells 110 are combined and arranged.

[0044] Hereinafter, a battery module according to another embodiment of the present invention will be described with further reference to FIG.

[0045] FIG. 5 is a view showing a state in which a cell in which a high temperature phenomenon occurs is removed from a battery module according to another embodiment of the present invention.

[0046] Referring to FIG. 5, a battery module 100 according to another embodiment of the present invention may include at least one spring 410 at an upper portion of each of a plurality of battery cells 110, pressing the battery cell 110 downward. For example, a plurality of springs 410 may be provided along the length direction (x-axis direction) of the battery cells 110. The battery cells 110 may be pressed downward due to the elasticity of the springs 410. In this case, when a battery cell 110' experiencing a high temperature phenomenon occurs as shown in FIG. 5, the battery cell 110' experiencing a high temperature phenomenon can be pressed downward and ejected more quickly because it is pressed by the spring 410. In other words, the battery cell 110' experiencing a high temperature phenomenon can be effectively pressed and ejected without or in addition to nitrogen injection through the injection nozzle 500.

[0047] 5, after the battery cell 110' in which the high temperature phenomenon has occurred is ejected, the spring 410 loses its elasticity and is placed in the space vacated by the ejected battery cell 110' in which the high temperature phenomenon has occurred, thereby filling at least a portion of the space formerly occupied by the battery cell 110' in which the high temperature phenomenon has occurred. As a result, the remaining battery cells 110 can maintain their stacked structure.

[0048] Hereinafter, a battery module according to still another embodiment of the present invention will be described with further reference to FIG.

[0049] FIG. 6 is a view showing a state in which a cell in which a high temperature phenomenon has occurred is removed from a battery module according to still another embodiment of the present invention.

[0050] Referring to FIG. 6 , a battery module 100 according to another embodiment of the present invention includes a bottom portion 240 and a plurality of opening / closing portions 241 corresponding to the battery cells 110. The opening / closing portions 241 are normally closed and may be configured to open when an abnormal condition occurs and a certain level of heat or pressure is generated and applied. This configuration may be implemented in various ways. For example, a portion supporting the opening / closing portion 241 may be fixed by the phase-change material layer 400 under normal conditions. When the phase-change material layer 400 is removed, the portion supporting the opening / closing portion 241 may also be removed and opened. Alternatively, the joint portion between the opening / closing portions 241 may be configured to have a lower melting point or a smaller thickness than the other portions, so that it melts first at high temperatures, thereby opening the opening / closing portion 241. By providing the separately set opening / closing portions 241, a battery cell 110′ experiencing a high temperature phenomenon can be more quickly evacuated to the outside.

[0051] In this embodiment, terms indicating directions such as front, back, left, right, up, and down are used, but these terms are merely for convenience of explanation and may change depending on the position of the target object, the position of the observer, etc.

[0052] 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.

[0053] The battery module or battery pack may be applied to various devices, specifically, but not limited to, transportation means such as electric bicycles, electric cars, and hybrids, and energy storage systems (ESS), and may be applied to various devices that can use secondary batteries.

[0054] 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. [Explanation of symbols]

[0055] 100: Battery module 110: Battery cell 120: Battery cell assembly 200:Module frame 240: Bottom part 241: Opening and closing section 300: End plate 400: Phase change material layer 410: Spring 500: Injection nozzle

Claims

1. a battery cell assembly formed by stacking a plurality of battery cells upright in one direction with one face facing each other; a module frame that houses the battery cell assembly and includes a bottom portion, the bottom portion being parallel to the one direction and positioned below the plurality of battery cells; and a phase change material layer disposed under the battery cell assembly and over the bottom portion; The phase change material layer is melted and erased at a portion corresponding to a battery cell where a high temperature phenomenon occurs among the plurality of battery cells, The bottom part is opened at the portion where the phase change material layer is removed, and the battery cell in which the high temperature phenomenon occurs is ejected to the outside.

2. The battery module according to claim 1 , wherein an injection nozzle for injecting nitrogen gas is formed on an upper surface of the module frame.

3. The battery module of claim 2 , wherein the battery cell in which the high temperature phenomenon occurs is pressurized downward and discharged by injecting nitrogen through the injection nozzle.

4. The battery module according to claim 3 , wherein the bottom portion is broken and opened when the battery cell in which the high temperature phenomenon occurs is pressed downward.

5. The battery module according to claim 1 , wherein a lubricant is applied between the plurality of battery cells.

6. The battery module according to claim 1 , further comprising at least one spring at an upper portion of each of the plurality of battery cells for pressing each of the plurality of battery cells downward.

7. 7. The battery module according to claim 6, wherein after the battery cell in which the high temperature phenomenon occurred is ejected, the spring fills at least a part of the space in which the battery cell in which the high temperature phenomenon occurred was disposed.

8. The battery module according to claim 1 , wherein the bottom portion includes a plurality of opening / closing portions corresponding to the respective battery cells.

9. The battery module according to claim 8 , wherein the opening / closing part is configured to be opened by heat or pressure applied by the battery cell in which the high temperature phenomenon occurs.

10. A battery pack comprising the battery module according to any one of claims 1 to 9.

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