Battery module and battery pack including same

Abstract

The battery module according to an embodiment of the present invention comprises: a battery cell assembly formed by stacking multiple battery cells; a module frame for containing the battery cell assembly, the module frame comprising a bottom portion; and a phase change material layer disposed on the lower portion of the battery cell assembly. The phase change material layer is configured such that a part thereof corresponding to a battery cell which has undergone a high-temperature phenomenon among the multiple battery cells, is melted and removed, and the bottom portion is opened by the removed part of the phase change material layer, thereby discharging the battery cell which has undergone a high-temperature phenomenon.

Description

Battery module and battery pack including the same

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

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0168581, filed November 28, 2023, the entire contents of which are incorporated herein by reference.

[0003] 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 cope with a temperature increase in one battery cell within the battery module.

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

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

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

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

[0008] Recently, secondary batteries have been widely used not only in small devices like portable electronic devices, but also in medium- to large-sized devices like automobiles and power storage devices. For applications in medium- to large-sized devices, numerous secondary batteries can be electrically connected to increase capacity and output. Pouch-type secondary batteries are increasingly being used due to their advantages, such as easy stacking and lightweight design.

[0009] Secondary batteries used in small devices are configured with two to three battery cells, but secondary batteries used in medium to large devices such as automobiles utilize battery modules in which multiple battery cells are electrically connected. These battery modules have improved capacity and output by forming a battery cell assembly in which multiple battery cells are connected in series or parallel. In addition, one or more battery modules may be mounted together with various control and protection systems, such as a Battery Disconnect Unit (BDU), a Battery Management System (BMS), and a cooling system, to form a battery pack.

[0010] Battery modules and packs, which are densely packed with numerous battery cells, can be vulnerable to fire. For example, if a single battery cell experiences an abnormally high temperature and ignites, the heat can easily spread to adjacent cells, leading to a larger fire. Therefore, even if a fire breaks out in a few battery cells, the fire can spread beyond the battery module or pack to encompass the entire battery rack or power storage device, increasing the risk of casualties and potentially causing significant economic losses. Therefore, it is crucial to quickly and accurately extinguish fires before all battery modules within the battery rack or power storage device are completely consumed or damaged.

[0011] Various fire suppression technologies have been proposed for devices containing battery modules, such as power storage devices. However, effective fire suppression techniques remain elusive. In particular, fires originating from lithium-ion batteries within battery modules are difficult to extinguish with standard fire extinguishing agents. Furthermore, in densely packed battery modules, it is difficult to selectively extinguish a fire in a single battery module. Therefore, a method is needed to effectively prevent a fire from spreading into a larger one by isolating a battery cell that has experienced high temperatures from other cells.

[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 effectively extinguish a fire even if a fire occurs in some battery cells and prevent the fire from spreading to a larger fire.

[0013] However, the problems to be solved by the embodiments of the present invention are not limited to the problems described above and can be expanded in various ways within the scope of the technical ideas included in the present invention.

[0014] A battery module according to one embodiment of the present invention comprises a battery cell assembly formed by stacking a plurality of battery cells, a module frame that accommodates 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 erased at a portion corresponding to a battery cell in which a high temperature phenomenon has occurred among the plurality of battery cells, and the bottom portion is opened at a portion where the phase change material layer has been erased so that the battery cell in which the high temperature phenomenon has occurred is discharged to the outside.

[0015] An injection nozzle into which nitrogen gas is injected can be formed on the upper surface of the above module frame.

[0016] By injecting nitrogen through the injection nozzle, the battery cell in which the high temperature phenomenon occurred can be pressurized downward and discharged.

[0017] The above bottom part can be broken and opened by the battery cell in which a high temperature phenomenon has occurred being pressed downward.

[0018] A lubricant may be applied between the plurality of battery cells.

[0019] At least one spring may be further included on the upper portion of each of the plurality of battery cells to press each of the plurality of battery cells downward.

[0020] After the battery cell in which the high temperature phenomenon occurred is discharged, the spring can fill at least a portion of the space in which the battery cell in which the high temperature phenomenon occurred was placed.

[0021] The above bottom portion may include a plurality of opening and closing portions corresponding to each of the battery cells.

[0022] The above opening and closing part may be configured to be opened by heat or pressure applied by the battery cell in which the high temperature phenomenon has occurred.

[0023] A battery pack according to one embodiment of the present invention includes the battery module.

[0024] According to embodiments of the present invention, a battery module and a battery pack including the same can be provided, which can prevent a fire by early separating a battery cell in which a high temperature phenomenon has occurred from other battery cells before a fire occurs.

[0025] 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.

[0026] Figure 1 is a perspective view showing a battery module according to one embodiment of the present invention.

[0027] Figure 2 is an exploded perspective view of the battery module of Figure 1.

[0028] Figure 3 is a drawing showing a cross-section along line A-A' of Figure 1.

[0029] Figure 4 is a drawing showing a state of discharging a cell in which a high temperature phenomenon occurred in Figure 3.

[0030] FIG. 5 is a drawing illustrating a state in which a cell in which a high temperature phenomenon has occurred is discharged in a battery module according to another embodiment of the present invention.

[0031] FIG. 6 is a drawing illustrating a state in which a cell in which a high temperature phenomenon has occurred is discharged in a battery module according to another embodiment of the present invention.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] Hereinafter, a battery module according to one embodiment of the present invention will be described with reference to FIGS. 1 to 4.

[0039] 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 taken along line A-A' of FIG. 1, and FIG. 4 is a view showing a state in which a cell in which a high temperature phenomenon has occurred in FIG. 3 is discharged.

[0040] Referring to FIGS. 1 to 3, a battery module (100) according to one 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.

[0041] First, the battery cell (110) may be a pouch-type battery cell, but is not limited thereto, and various types of battery cells may be applied. A plurality of battery cells are stacked so as to be electrically connected to each other to form a battery cell assembly (120). For example, as illustrated in FIG. 2, a plurality of battery cells (110) may be stacked along 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. A busbar frame (not shown) may be positioned 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 busbar frame is not limited thereto, and may be arranged to cover the other side of the battery cell assembly (120). That is, as long as the position in which the electrode leads (111) and the busbar can be electrically connected depending on the protruding direction of the electrode leads (111), the busbar frame may also be appropriately changed to correspond thereto, and is not particularly limited thereto.

[0042] These battery cells (110) are stacked along one direction to form a battery cell assembly (120). Specifically, the battery cells (110) can be stacked along the one direction while standing upright with one side of the battery cells (110) facing each other.

[0043] The module frame (200) according to the present embodiment is a member that accommodates a battery cell assembly (120) therein, and may include two side portions (210, 220), an upper portion (230), and a bottom portion (240). In addition, one side (x-axis direction) and the other side (-x-axis direction) of the module frame (200) may be open, and the battery cell assembly (120) may be accommodated through the open one side or the other side. The module frame (200) illustrated in FIG. 2 may be a monoframe in which the two side portions (210, 220), the upper portion (230), and the bottom portion (240) are integrated. That is, it may be manufactured by extrusion molding, and the two side portions (210, 220), the upper portion (230), and the bottom portion (240) may be integrated. Although not specifically illustrated, as another embodiment of the present invention, a module frame in which a U-shaped frame and an upper plate are welded to each other, or an inverted U-shaped frame and a lower plate are welded to each other, is also possible, and various shapes of frames can be applied without particular limitation. Looking at the stacking direction of the module frame (200) and the battery cells (110), the battery cells (110) can be stacked from one side (210) to the other side (220) such that one side of the battery cells (110) is parallel to one side of the side portions (210, 220) of the module frame (200).

[0044] Meanwhile, the battery module (100) according to the present embodiment may further include end plates (300) positioned on the open one side and the other side of the module frame (200), respectively. The end plates (300) may be positioned to cover the battery cell assembly (120) on the open one side and the other side of the module frame (200). The 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 assembly (120) and other electrical components from external impact.

[0045] The battery module (100) may further include a phase change material layer (400) located 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). The phase change material is a material that repeatedly exhibits the characteristics of heat storage and heat generation by absorbing heat when the surrounding temperature rises and releasing heat by crystallizing when the surrounding temperature drops. In the normal state of the battery cell (110), the phase change material may absorb heat from the battery cell (110) to obtain a cooling effect. In addition, the phase change material included in the phase change material layer (400) may melt at a specific temperature, particularly at a high temperature close to the ignition temperature of the battery cell (110), so that a portion supporting the battery cell (110) where a high temperature phenomenon occurs may be erased. As such phase change materials, paraffin, various salt hydrates, polyethylene glycol (polyethylenglycol, PSG), etc. can be used. In addition, the phase change material layer (400) may not only contain the phase change material alone, but may also be used mixed with various materials for ease of handling during the process, etc., and is not particularly limited.

[0046] As described above, when a high temperature phenomenon occurs in some of the plurality of battery cells (110), the phase change material layer (400) can be erased by absorbing the heat generated from the corresponding battery cell and melting. That is, as illustrated in FIG. 4, a portion corresponding to a battery cell (110') in which a high temperature phenomenon occurs is erased by melting, and then the bottom portion (240) of the corresponding portion is opened, so that the battery cell (110') in which the high temperature phenomenon occurred can be discharged to the outside. The process of the battery cell (110') in which the high temperature phenomenon occurred being discharged to the outside can be accomplished by falling downward due to gravity or the pressure of the venting gas generated from the battery cell (110') in which the high temperature phenomenon occurred. At this time, the bottom portion (240) of the lower portion of the phase change material layer (400) can be opened by being fractured by the high temperature and pressure.

[0047] Alternatively, in addition, it is also possible to artificially discharge the battery cell (110') in which the high temperature phenomenon has occurred before ignition is completely achieved. For this purpose, an injection nozzle (500) for injecting nitrogen may be further included in the upper surface (210) of the module frame (200). This injection nozzle (500) is connected to a nitrogen storage container (not shown) separately provided on the outside of the battery module (100), and when a specific temperature is reached, it opens to inject nitrogen into the battery module (100), thereby increasing the pressure inside the battery module (100). By this, the battery cell (110) in which the high temperature phenomenon has occurred can be pressurized from above, and in this process, only the battery cell (110') in which the high temperature phenomenon has occurred can be pushed downward and discharged because the phase change material layer (400) thereunder is eliminated by the high temperature and pressure. Therefore, the battery cell (110') in which the high temperature phenomenon has occurred can be discharged before ignition occurs, thereby preventing ignition.

[0048] Meanwhile, when discharging a battery cell (110') in which a high temperature phenomenon has occurred in this manner, lubricant may be applied between the battery cells (110) to facilitate smooth discharge. This reduces friction between neighboring battery cells (110), thereby achieving the effect of more quickly discharging the battery cell (110') in which a high temperature phenomenon has occurred to the outside.

[0049] As described above, according to one embodiment of the present invention, when a high-temperature phenomenon occurs in a battery cell (110') including a phase change material layer (400) at the bottom of a battery cell assembly (120), the phase change material layer (400) melts and disappears, thereby allowing the battery cell (110') in which the high-temperature phenomenon occurs to be quickly discharged to the outside (bottom), thereby isolating the battery cell (110') in which the high-temperature phenomenon occurs from other battery cells (110), thereby preventing the spread of fire and preventing the occurrence of fire, thereby improving the safety of the battery module (100). Meanwhile, in the present embodiment, a case where the battery cell assembly (120) is housed in the module frame (200) and discharged to the outside of the module frame (200) has been described as an example, but the present invention is not limited thereto, and can be applied to any structure in which a plurality of battery cells (110) are arranged in combination.

[0050] Hereinafter, a battery module according to another embodiment of the present invention will be described with further reference to FIG. 5.

[0051] FIG. 5 is a drawing illustrating a state in which a cell in which a high temperature phenomenon has occurred is discharged in a battery module according to another embodiment of the present invention.

[0052] Referring to FIG. 5, in a battery module (100) according to another embodiment of the present invention, at least one spring (410) for pressing the battery cell (110) downward may be included on the upper portion of each of the plurality of battery cells (110). For example, a plurality of springs (410) may be provided along the longitudinal direction (x-axis direction) of the battery cell (110). Due to the elasticity of the springs (410), the battery cell (110) may be pressed downward. At this time, when a battery cell (110') in which a high temperature phenomenon occurs as illustrated in FIG. 5 occurs, the battery cell (110') in which a high temperature phenomenon occurs can be pressurized and discharged more quickly downward because it is pressurized by the spring (410). That is, it is possible to effectively pressurize and discharge the battery cell (110') in which a high temperature phenomenon occurs without, or together with, nitrogen injection through the injection nozzle (500).

[0053] In addition, as illustrated in FIG. 5, after the battery cell (110') in which the high temperature phenomenon occurred is discharged, the spring (410) that has lost its elasticity is placed in the empty space as it is after the battery cell (110') in which the high temperature phenomenon occurred is discharged, so that at least a portion of the space in which the battery cell (110') in which the high temperature phenomenon occurred was placed can be filled. As a result, the remaining battery cells (110) can also maintain a stacked structure.

[0054] Hereinafter, a battery module according to another embodiment of the present invention will be described with further reference to FIG. 6.

[0055] FIG. 6 is a drawing illustrating a state in which a cell in which a high temperature phenomenon has occurred is discharged in a battery module according to another embodiment of the present invention.

[0056] Referring to FIG. 6, a battery module (100) according to another embodiment of the present invention includes a plurality of opening / closing parts (241) corresponding to each of the battery cells (110) in the bottom part (240). These opening / closing parts (241) may be configured to be closed under normal conditions, but to open only when an abnormal situation occurs and a certain level of heat or pressure is generated and applied. This configuration may be implemented in various ways. For example, under normal conditions, a portion supporting the opening / closing parts (241) is fixed by a phase change material layer (400), but when the phase change material layer (400) is erased, a configuration is also possible in which the portion supporting the opening / closing parts (241) is erased together and opened. Alternatively, the joint between the opening / closing parts (241) may be configured to have a lower melting point or a smaller thickness than other portions so as to melt first at a high temperature, thereby allowing the opening / closing parts (241) to open. By providing a separately set opening / closing part (241) in this way, the battery cell (110') in which a high temperature phenomenon has occurred can be discharged to the outside more quickly.

[0057] 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.

[0058] One or more 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.

[0059] The above battery module or battery pack can be applied to various devices. Specifically, it can be applied to transportation vehicles such as electric bicycles, electric vehicles, and hybrid vehicles, 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.

[0060] 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.

[0061] [Explanation of symbols]

[0062] 100: Battery module

[0063] 110: Battery cell

[0064] 120: Battery cell assembly

[0065] 200: Module Frame

[0066] 240: Bottom

[0067] 241: Opening and closing parts

[0068] 300: End Plate

[0069] 400: Phase change material layer

[0070] 410: Spring

[0071] 500: Injection nozzle

Claims

1. A battery cell assembly formed by stacking multiple battery cells; A module frame accommodating the above battery cell assembly and including a bottom portion, and Including a phase change material layer disposed at the bottom of the above battery cell assembly, The above phase change material layer melts and disappears in a portion corresponding to a battery cell among the plurality of battery cells in which a high temperature phenomenon has occurred. A battery module in which the bottom part is opened at a portion where the phase change material layer is removed, and the battery cell in which the high temperature phenomenon occurs is discharged to the outside.

2. In paragraph 1, A battery module in which an injection nozzle for injecting nitrogen gas is formed on the upper surface of the module frame.

3. In paragraph 2, A battery module in which a battery cell in which a high-temperature phenomenon has occurred is pressurized downward and discharged by injecting nitrogen through the injection nozzle.

4. In paragraph 3, The above bottom part is a battery module in which a battery cell in which a high temperature phenomenon has occurred is broken and opened by being pressed downward.

5. In paragraph 1, A battery module with a lubricant applied between the plurality of battery cells.

6. In paragraph 1, A battery module further comprising at least one spring on the upper portion of each of the plurality of battery cells for pressurizing each of the plurality of battery cells downward.

7. In paragraph 6, A battery module in which the spring fills at least a portion of the space in which the battery cell in which the high temperature phenomenon occurred was placed after the battery cell in which the high temperature phenomenon occurred is discharged.

8. In paragraph 1, The bottom part is a battery module including a plurality of opening and closing parts corresponding to each of the battery cells.

9. In paragraph 8, A battery module in which the above opening / closing part is configured to open due to heat or pressure applied by a battery cell in which the above high-temperature phenomenon has occurred.

10. A battery pack including a battery module according to paragraph 1.

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