Battery module and battery pack containing the same

Abstract

A battery module according to one embodiment of the present invention may include a battery cell stack in which a plurality of battery cells are stacked, a module frame that houses the battery cell stack, an inlet port through which a refrigerant flows into the module frame, an outlet port through which the refrigerant flows out from the module frame, and expansion members disposed at the inlet port and the outlet port, respectively, which expand in volume when they reach a predetermined temperature.

Description

Technical Field

[0001] [Cross - reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2024 - 0032007 filed on March 6, 2024, and all the contents disclosed in the literature of the 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 specifically, to a battery module and a battery pack including the same that improve cooling efficiency, enhance cooling performance, and prevent venting gas released due to a thermal runaway phenomenon occurring in the battery module from propagating to an adjacent battery module.

Background Art

[0003] With the development of technology and the increasing demand for mobile devices, the demand for secondary batteries as an energy source has been rapidly increasing. Accordingly, many studies on secondary batteries that can meet various requirements have been conducted.

[0004] Secondary batteries have attracted much attention not only as an energy source for mobile devices such as mobile phones, digital cameras, and notebook computers, but also as an energy source for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles.

[0005] Recently, with the increasing need for large - capacity secondary battery structures, including their use as an energy storage source for secondary batteries, the demand for medium - to - large - sized module - structured battery packs that aggregate battery modules in which a large number of secondary batteries are connected in series / parallel has been increasing.

[0006] On the other hand, when configuring a battery pack by connecting a plurality of battery cells in series / parallel, it is common to configure a battery module consisting of at least one battery cell and then add other components using at least one battery module to configure the battery pack.

[0007] The battery cells that make up such medium- and large-sized battery modules are composed of rechargeable secondary batteries, and such high-power, high-capacity secondary batteries generate a large amount of heat during the charging and discharging process. In this case, the heat from many battery cells can accumulate in a confined space, potentially causing the temperature to rise rapidly and drastically. In other words, while high output can be obtained in battery modules with many battery cells stacked on top of each other and in battery packs equipped with such modules, it is not easy to remove the heat generated by the battery cells during charging and discharging. If the heat from the battery cells is not properly dissipated, the battery cells will deteriorate more quickly, shortening their lifespan and increasing the risk of explosion or fire.

[0008] Furthermore, battery modules included in vehicle battery packs are often exposed to direct sunlight and subjected to high-temperature conditions such as summer or desert regions. In addition, because numerous battery modules are densely arranged to increase the vehicle's driving range, flames or heat generated in one battery module can easily spread to neighboring modules, potentially leading to the battery pack itself catching fire or exploding.

[0009] Furthermore, battery packs are heavy due to their structure, which is composed of numerous battery modules, making them unsuitable for mounting in vehicles or other means of transportation. Therefore, there is a need to improve energy density.

[0010] Figure 1 is a perspective view showing a conventional battery pack. Figure 2 is an exploded perspective view of the battery pack shown in Figure 1.

[0011] Referring to Figures 1 and 2, a conventional battery pack 10 includes a lower pack frame 11 on which multiple battery modules 1 are mounted, an upper pack frame 12 located above the battery modules 1, and an internal beam 13 that demarcates the positions in the battery pack 10 where the battery modules 1 are mounted.

[0012] Thus, when battery modules 1 are installed inside a battery pack 10, the internal beams 13 that partition the battery modules 1 reduce the energy density of the battery pack 10. Therefore, in order to meet the efficiency requirements of a device, a larger number of battery packs 10 must be installed, which presented a problem. In addition, the weight of the battery pack 10 limited the number of battery packs 10 that could be installed in a device. Consequently, in order to reduce the weight of the battery pack 10 while simultaneously increasing its energy density, it was necessary to install a larger number of battery modules 1 inside the battery pack 10.

[0013] As shown in Figures 1 and 2, a conventional battery pack 10 has a configuration in which multiple battery modules 1 are housed. Therefore, in the event that a thermal runaway phenomenon occurs in any one of the multiple battery modules 1, there is a need for a structure or method that can prevent the venting gas generated in the battery module 1 that experienced the thermal runaway phenomenon from spreading to the other battery modules 1, thereby preventing the thermal runaway phenomenon from spreading to the other battery modules 1.

[0014] Furthermore, conventional battery modules 1 and battery packs 10 do not directly cool the battery cell stack provided in the battery module 1, so there is a need for a more effective method to improve cooling efficiency. [Overview of the Initiative] [Problems that the invention aims to solve]

[0015] The problem that the present invention aims to solve is to provide a battery module and a battery pack including the same that can improve the cooling efficiency of the battery module, thereby improving cooling performance, and prevent venting gas released due to thermal runaway phenomena occurring within the battery module from propagating to adjacent battery modules.

[0016] However, the problems that the embodiments of the present invention aim to solve are not limited to those described above, and can be broadly extended within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0017] A battery module according to one embodiment of the present invention may include a battery cell stack in which a plurality of battery cells are stacked, a module frame that houses the battery cell stack, an inlet port through which a refrigerant flows into the module frame, an outlet port through which the refrigerant flows out from the module frame, and expansion members disposed at the inlet port and the outlet port, respectively, which expand in volume when they reach a predetermined temperature.

[0018] The battery module further includes end plates that close both open sides of the module frame and include refrigerant openings formed for the refrigerant to flow in or out, and the expansion member can expand to close the refrigerant openings when it reaches the predetermined temperature.

[0019] The inlet port may be formed on an end plate located on one of the two sides of the module frame, and the outlet port may be formed on an end plate located on the other side of the module frame.

[0020] The upper end of the refrigerant opening may be located above the center with respect to the height of the battery cell stack, and the lower end of the refrigerant opening may be located below the center with respect to the height of the battery cell stack.

[0021] The length of the refrigerant opening from the upper end to the lower end can be between 0.5 and 0.9 times the length of the end plate from the upper corner to the lower corner.

[0022] The expansion member may include a main body formed to surround the periphery of the refrigerant opening and a through-hole formed to allow the refrigerant to flow in or out.

[0023] The main body can be formed with an inclination such that its cross-sectional area decreases as it moves away from the refrigerant opening.

[0024] The main body portion can include a plurality of fine holes formed such that the refrigerant can penetrate into the expansion member.

[0025] Each of the inflow port and the outflow port includes a cover member formed to incline downward on the surface facing the refrigerant opening, and the inflow port and the outflow port can have a decreasing cross-sectional area in the direction from the upper side to the lower side.

[0026] The expansion member can expand toward the internal spaces of the inflow port and the outflow port during expansion to close the refrigerant opening.

[0027] The expansion member can include a foaming layer that foams and expands in volume when reaching a first temperature, and a chemical-resistant layer laminated on both surfaces of the foaming layer and softened at a second temperature lower than the first temperature.

[0028] The chemical-resistant layer can be thermally decomposed at a third temperature higher than the second temperature.

[0029] The third temperature can be higher than or the same as the first temperature.

[0030] The foaming layer can include at least one of silica gel, a foamed silicon pad, a polyurethane foam, and polypropylene.

[0031] The chemical-resistant layer can include at least one of PVC, PET, nylon, PFA, PVDF, and PTFE.

[0032] The module frame can include at least one venting portion formed at the upper end for discharging the internal gas.

[0033] The venting section may include a venting hole that is open to allow internal gas to be discharged, and an opening that closes the venting hole when the pressure or temperature inside the module frame is below a predetermined internal pressure or temperature, and opens the venting hole when the pressure or temperature inside the module frame reaches the predetermined internal pressure or temperature.

[0034] The opening may include a bursting member that ruptures when it reaches a predetermined internal pressure or decomposes thermally when it reaches a predetermined internal temperature.

[0035] The refrigerant may include an insulating refrigerant or a non-flammable refrigerant.

[0036] A battery pack according to another embodiment of the present invention includes a plurality of battery modules according to the above-described embodiment, and includes refrigerant lines connected to the inlet port and the outlet port, respectively, wherein the expansion member can close the inlet port and the outlet port to block the flow of the refrigerant into the refrigerant line when it reaches a predetermined temperature. [Effects of the Invention]

[0037] The battery module and battery pack containing the same according to the embodiment of the present invention can increase the cooling efficiency of direct cooling of the refrigerant to the battery cells, thereby increasing the energy density.

[0038] Furthermore, since it is possible to prevent venting gas released due to thermal runaway occurring within the battery module from propagating to adjacent battery modules, the stability of the battery module and the battery pack containing it can be improved even if specific conditions such as thermal runaway occur.

[0039] Furthermore, because the cooling effect of the refrigerant can be maintained for a longer period in the event of thermal runaway, the stability of the battery module and the battery pack containing it can be further improved.

[0040] The effects of the present invention are not limited to those described above, and other effects not mentioned will be clearly understood by those skilled in the art from the claims. [Brief explanation of the drawing]

[0041] [Figure 1] This is a perspective view showing a conventional battery pack. [Figure 2] Figure 1 is an exploded perspective view of the battery pack. [Figure 3] This is a perspective view showing a battery module according to one embodiment of the present invention. [Figure 4] Figure 3 is an exploded perspective view of the battery module. [Figure 5] This is a plan view showing one of the battery cells included in the battery cell stack shown in Figure 4. [Figure 6] Figure 3 is a diagram of the battery module viewed along the -x axis in the yz plane. [Figure 7] This is a diagram showing the inflow port along the -x axis in the yz plane. [Figure 8] This is a front view of the expansion member. [Figure 9] (a) is a diagram showing the expansion member before it expands in the inlet port, and (b) is a diagram showing the expansion member after it expands in the inlet port. [Figure 10] This is a cross-sectional view of the expansion member. [Figure 11] This is a conceptual diagram to explain the operation of the venting section. [Figure 12] This is a perspective view of a battery pack including a battery module according to an embodiment of the present invention. [Figure 13] Figure 12 is an exploded perspective view of the battery pack. [Figure 14] This is a conceptual diagram illustrating the position of the expansion component in the battery pack. [Modes for carrying out the invention]

[0042] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. The present invention can be realized in a variety of different forms and is not limited to the embodiments described herein.

[0043] To clearly explain the present invention, descriptive parts that are unnecessary have been omitted, and the same or similar reference numerals are used throughout the specification for identical or similar components.

[0044] Furthermore, the dimensions and thicknesses of each component shown in the drawings are arbitrary for the sake of explanation, and therefore the present invention is not necessarily limited to those shown. In the drawings, the thicknesses are shown enlarged to clearly represent various layers and regions. Also, in the drawings, the thicknesses of some layers and regions are shown exaggerated for the sake of explanation.

[0045] Furthermore, when we say that a layer, membrane, region, plate, or other part is "on top" of another part, this includes not only the case where it is "directly above" the other part, but also the case where the other part is in between. Conversely, when we say that one part is "directly above" another part, it means that there is no other part in between. Also, being "on top" of a reference part means being located above or below the reference part, and does not necessarily mean being located "up" in the opposite direction of gravity.

[0046] Furthermore, terms indicating direction such as front, back, left, right, up, and down were used, but these terms are merely for explanatory convenience and can change depending on the position of the object being observed, the observer's position, and so on.

[0047] Furthermore, when a specification states that a part of it "includes" a certain component, unless otherwise specified, this means that it may include other components rather than excluding them.

[0048] Furthermore, throughout the specification, "on a plane" means when the subject is viewed from above, and "on a cross-section" means when the subject is viewed from the side of a cross-section obtained by cutting the subject perpendicularly.

[0049] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0050] Figure 3 is a perspective view showing a battery module according to one embodiment of the present invention. Figure 4 is an exploded perspective view of the battery module of Figure 3. Figure 5 is a plan view showing one of the battery cells included in the battery cell stack of Figure 4.

[0051] Referring to Figures 3 to 5, a battery module 100 according to one embodiment of the present invention includes a battery cell stack 120 formed by stacking a plurality of battery cells 110, a module frame 200 that houses the battery cell stack 120, end plates 400 that close both open sides of the module frame 200, an inlet port 510 formed on the end plate 400 so that a coolant flows into the interior of the module frame 200, an outlet port 516 formed on the other end plate 400 so that a coolant flows out from the interior of the module frame 200, and expansion members 520 that are positioned at the inlet port 510 and the outlet port 516, respectively, and whose volume expands when a predetermined temperature is reached.

[0052] First, the battery cell 110 may be a pouch-type battery in which an electrode assembly having electrode leads 111 protruding in one direction or both directions is housed in a pouch case 114. However, this is just one example, and a battery cell according to another embodiment of the present invention may be a prismatic battery. For the sake of convenience, the following explanation will be based on the battery cell 110, which is a pouch-type battery.

[0053] The battery cell 110 may be in the shape of a rectangular sheet. The battery cell 110 can be formed by housing an electrode assembly in a laminated sheet pouch case 114 containing a resin layer and a metal layer, and then bonding the outer periphery of the pouch case 114. As an example, the battery cell 110 may have a structure in which two electrode leads 111 face each other and protrude from one end and the other end of the cell body 113, respectively. In another embodiment, the battery cell 110 may have a structure in which all electrode leads 111 protrude in one direction. One of the electrode leads 111 is the positive electrode lead and the other is the negative electrode lead.

[0054] The battery cell 110 can be manufactured by sealing the periphery of the pouch case 114 with an electrode assembly (not shown) housed inside the pouch case 114. As another example, the battery cell 110 can be manufactured with one side of the pouch case 114 folded over to house the electrode assembly, while the remaining side is sealed.

[0055] The laminated sheet pouch case 114 may include an inner resin layer for sealing, a metal layer to prevent penetration of materials, and an outermost outer resin layer. With respect to the electrode assembly inside the pouch case 114, the inner resin layer may be located on the innermost side, the outer resin layer on the outermost side, and the metal layer may be located between the inner and outer resin layers.

[0056] The outer resin layer may have excellent tensile strength and weather resistance relative to its thickness, as well as electrical insulation, to protect the electrode assembly from the outside. Such an outer resin layer may include polyethylene terephthalate (PET) resin or nylon resin. A metal layer may prevent air, moisture, etc., from entering the pouch-type secondary battery. Such a metal layer may include aluminum (Al). The inner resin layer may be heat-sealed by heat and / or pressure applied with the electrode assembly assembled. Such an inner resin layer may include casted polypropylene (CPP) or polypropylene (PP).

[0057] The pouch case 114 is divided into two parts, and a recessed storage section can be formed in at least one of the two parts on which an electrode assembly can be placed. The inner resin layers of the two parts of the pouch case 114 are joined together along the outer circumference of this storage section, thereby sealing the pouch case 114 and manufacturing a battery cell 110, which is a pouch-type battery.

[0058] A battery cell 110 can be composed of multiple cells, and multiple battery cells 110 can be stacked so as to be electrically connected to each other to form a battery cell stack 120. In particular, as shown in Figure 4, multiple battery cells 110 can be stacked along one direction parallel to the y-axis while standing upright with one face of each cell body 113 facing each other. This allows the electrode leads 111 to protrude in a direction perpendicular to the direction in which the battery cells 110 are stacked. That is, in a battery cell 110, one electrode lead 111 can protrude in the x-axis direction, and the other electrode lead 111 can protrude in the -x-axis direction. If the electrode leads 111 protrude in only one direction, the electrode leads 111 will protrude in either the x-axis direction or the -x-axis direction.

[0059] The module frame 200 may be for protecting the battery cell stack 120 and the electrical components connected thereto from external physical shocks. The battery cell stack 120 and the electrical components connected thereto can be housed in the internal space of the module frame 200.

[0060] The structure of the module frame 200 can be diverse. According to one embodiment of the present invention, the structure of the module frame 200 may be a monoframe structure. Here, the monoframe may be in the form of a metal plate in which the upper and lower surfaces (in the z-axis direction and the -z-axis direction) and both sides (in the y-axis direction and the -y-axis direction) are integrated. The monoframe can be manufactured by extrusion molding.

[0061] However, the structure of the module frame 200 is not limited to this, and in other embodiments, the module frame 200 may have a structure in which a U-shaped frame and an upper plate are joined. In this case, the U-shaped frame may have a bottom surface and two sides that extend upward from both corners of the bottom surface, and the upper plate may be in the form of a plate. At this time, each frame or plate constituting the U-shaped frame may be manufactured by press molding. Furthermore, the structure of the module frame 200 may be provided as an L-shaped frame structure in addition to a monoframe or a U-shaped frame, and may be provided in a variety of structures not described in the examples above.

[0062] The module frame 200 may be open on both sides. More specifically, the module frame 200 may be provided in an open configuration along the longitudinal direction of the battery cell 110. In this case, the front and rear surfaces of the battery cell stack 120 do not need to be obscured by the module frame 200. The front and rear surfaces of the battery cell stack 120 can be obscured by the busbar assembly 300 and end plates 400, etc., thereby protecting the front and rear surfaces of the battery cell stack 120 from external physical shocks, etc.

[0063] The battery module 100 may include busbar assemblies 300 located on both sides of the battery cell stack 120. Specifically, the busbar assemblies 300 can be positioned in both directions from which the electrode leads 111 of the battery cells 110 contained in the battery cell stack 120 protrude. The busbar assemblies 300 can electrically connect the battery cells 110 constituting the battery cell stack 120 in series or parallel. The busbar assemblies 300 may each include a busbar frame 310, busbars 320, and terminal busbars.

[0064] The busbar frame 310 is located on one surface of the battery cell stack 120, covering one surface of the battery cell stack 120, and may also serve to guide the connection between the battery cell stack 120 and external equipment. The busbar frame 310 can be located on the front (x-axis direction) and rear (-x-axis direction) of the battery cell stack 120.

[0065] A busbar 320 can be mounted on the busbar frame 310. Specifically, the inner surface of the busbar frame 310 is connected to the front (x-axis direction) and rear (-x-axis direction) of the battery cell stack 120, and the outer surface of the busbar frame 310 is connected to the busbar 320.

[0066] The busbar frame 310 may include an electrically insulating material. The busbar frame 310 can restrict contact between the busbar 320 and other parts of the battery cell 110, except for the parts that are joined to the electrode leads (not shown), thereby preventing electrical short circuits.

[0067] The busbar 320 is mounted on one side of the busbar frame 310 and may be used to electrically connect the battery cell stack 120 or the battery cells 110 to an external equipment circuit. Since the busbar 320 is located on the busbar frame 310 and such a busbar assembly 300 is covered by the end plate 400 in Figure 4, it can be protected from external impacts and minimizes the reduction in battery durability due to external moisture and other factors.

[0068] The busbar 320 can be electrically connected to the battery cell stack 120 through the electrode leads of the battery cells 110. Specifically, the electrode leads 111 of the battery cells 110 can pass through slits formed in the busbar frame 310, then bend and connect to the busbar 320. The busbar 320 can connect the battery cells 110 constituting the battery cell stack 120 in series or parallel. There are no particular restrictions on the method of connection between the electrode leads 111 and the busbar 320; for example, welding can be used.

[0069] On the other hand, although not shown in Figures 3 and 4, the battery module 100 may include terminal busbars. The terminal busbars may include a first terminal busbar and a second terminal busbar, and the first terminal busbar and the second terminal busbar may have different polarities.

[0070] The terminal busbars are electrically connected to the busbars 320 or electrode leads and are used to electrically connect one battery module 100 to other battery modules 100. The first and second terminal busbars may have at least a portion exposed to the outside of the end plate 400 to connect one battery module 100 to other external battery modules 100, and the end plate 400 may be provided with terminal busbar openings (not shown) for this purpose. The terminal busbars can be connected to other battery modules 100 or BDUs (Battery Disconnect Units) through the portions exposed via the terminal busbar openings, forming HV (High Voltage) connections.

[0071] The end plates 400 can be positioned on both open sides (x-axis and -x-axis) of the module frame 200 and formed to cover the battery cell stack 120 by closing off the open sides of the module frame 200. Such end plates 400 can physically protect the battery cell stack 120 and other electrical components from external impacts.

[0072] The end plate 400 may include a refrigerant opening 410 formed for the inflow or outflow of refrigerant. The refrigerant opening 410 is an opening provided in the end plate 400, and is a hole that penetrates the end plate 400. This allows refrigerant to flow from the outside to the inside of the module frame 200 or out of the inside of the module frame 200 through the refrigerant opening 410, even when the end plate 400 is installed. The refrigerant opening 410 may be covered by an inflow port 510 or an outflow port 516, described later, and connected to a first refrigerant line 501 or a second refrigerant line 502, respectively.

[0073] The refrigerant opening 410 may be a hole formed by extending in the vertical direction (z-axis direction and -z-axis direction). The upper end of the refrigerant opening 410 may be located above the center with respect to the height of the battery cell stack 120. The lower end of the refrigerant opening 410 may be located below the center with respect to the height of the battery cell stack 120. Specifically, the length from the center of the refrigerant opening 410 to the upper end of the refrigerant opening 410 may be greater than or equal to the length from the upper corner of the end plate 400 to the upper end of the refrigerant opening 410. Also, the length from the center of the refrigerant opening 410 to the lower end of the refrigerant opening 410 may be greater than or equal to the length from the lower corner of the end plate 400 to the lower end of the refrigerant opening 410. More specifically, the length from the upper end to the lower end of the refrigerant opening 410 may be between 0.5 and 0.9 times the length from the upper corner to the lower corner of the end plate 400.

[0074] The refrigerant can flow directly into the interior of the module frame 200. By flowing into the interior of the module frame 200, the refrigerant can transfer heat generated from the battery cell stack 120, busbar assembly 300, or other electrical components housed in the module frame 200, while directly contacting them. However, the above does not limit the refrigerant to direct contact with the components housed in the module frame 200. In other words, the refrigerant may indirectly contact the components housed in the module frame 200. For example, the refrigerant can cool the components housed in the module frame 200 by flowing through the interior of the module frame 200 along a refrigerant channel formed inside the module frame 200.

[0075] The refrigerant may be a fluid. The refrigerant needs to be electrically insulated because it can come into direct contact with the battery cell stack 120, the busbar assembly 300, or other electrical components within the battery module 100. Therefore, the refrigerant may be an insulating refrigerant. As an example, the refrigerant may be an insulating oil. However, the type of refrigerant is not limited to what has been described above. For example, the refrigerant may be a non-flammable refrigerant because it must not ignite even when exposed to a high-temperature environment within the battery module 100.

[0076] In other words, in this embodiment, the refrigerant can directly cool the battery cell stack 120, busbar assembly 300, and other electrical components that generate heat within the battery module 100 by directly contacting them and transferring heat. Therefore, compared to conventional battery modules that indirectly cool the battery module using a heat sink or the like, the battery module 100 according to this embodiment of the present invention can improve cooling efficiency through direct cooling, thereby extending the battery life.

[0077] On the other hand, although not shown in Figure 4, the battery module 100 may further include a sealing assembly. The sealing assembly can be positioned on both open sides of the module frame 200 and formed to cover the battery cell stack 120. In other words, the sealing assembly is positioned between the end plate 400 and the battery cell stack 120, and can isolate both open sides of the module frame 200 from the external environment. Specifically, the sealing assembly can serve to seal the module frame 200 so that the refrigerant does not leak out when it is injected into the interior of the module frame 200.

[0078] Figure 6 is a view of the battery module from Figure 3 along the -x axis on the yz plane. Figure 7 is a view of the inlet port along the -x axis on the yz plane. Figure 8 is a front view of the expansion member. Figure 9(a) shows the expansion member before it expands in the inlet port, and (b) shows the expansion member after it expands in the inlet port.

[0079] Referring to Figures 6 to 9, the battery module 100 includes an inlet port 510 and an outlet port 516 for circulating a refrigerant inside the module frame 200, and expansion members 520 positioned inside the inlet port 510 and the outlet port 516, respectively. The inlet port 510 can be formed on an end plate 400 located on one of the sides of the module frame 200 so that the refrigerant flows into the module frame 200, and the outlet port 516 can be formed on an end plate 400 located on the other side of the module frame 200 so that the refrigerant flows out from the inside of the module frame 200. A detailed description of the expansion members 520 will be given later.

[0080] The refrigerant circulates through refrigerant lines 500 connected to the inlet port 510 and the outlet port 516, respectively. More specifically, the refrigerant moves from the refrigerant storage facility 2100 (described later) through the heat exchanger 2200 and then through the refrigerant lines 500, flows into the module frame 200 through the inlet port 510, flows out to the outside of the module frame 200 through the outlet port 516, and is then recovered back into the refrigerant storage facility 2100 through the refrigerant lines 500. On the other hand, since the outlet port 516 has the same shape and structure as the inlet port 510, the illustration of the outlet port 516 is omitted in Figures 6 and 7, and the following description of the contents that are the same as or corresponding to those of the inlet port 510 is omitted.

[0081] The refrigerant line 500 includes a first refrigerant line 501 connected to the inlet port 510 and a second refrigerant line 502 connected to the outlet port 516. The refrigerant line 500 may be a rigid, pipe-shaped member that allows the refrigerant to flow.

[0082] The inlet port 510 may have a shape corresponding to the refrigerant opening 410 in order to cover the refrigerant opening 410. As mentioned above, since the refrigerant opening 410 is a hole that extends in the vertical direction, the inlet port 510 may also have a shape that extends in the vertical direction. The inlet port 510 may also include a cover member 511 for covering the refrigerant opening 410 of the end plate 400. The cover member 511 may be formed with a downward inclination on the surface facing the refrigerant opening 410. This allows the cross-sectional area of ​​the inlet port 510 to decrease from the top to the bottom (-z axis direction).

[0083] Summarizing the shape and position of the refrigerant opening 410 as described above, the refrigerant opening 410 connected to the inlet port 510 can have its lower end positioned below the center, relative to the height of the battery cell stack 120. In other words, the lower end of the refrigerant opening 410 connected to the inlet port 510 can be positioned close to the lower corner of the end plate 400. Similarly, the refrigerant opening 410 connected to the outlet port 516 can have its upper end positioned above the center, relative to the height of the battery cell stack 120. In other words, the upper end of the refrigerant opening 410 connected to the outlet port 516 can be positioned close to the upper corner of the end plate 400.

[0084] If the lower end of the refrigerant opening 410 connected to the inlet port 510 is located above the center of the battery cell stack 120, the refrigerant will flow into the battery module 100 from a higher position, potentially causing bubbles to form inside the refrigerant. Such bubbles can hinder the cooling effect.

[0085] Furthermore, if the upper end of the refrigerant opening 410 connected to the outlet port 516 is located below the center of the battery cell stack 120, the refrigerant that flows into the battery module 100 will fill up to the height of the outlet port 516 and escape to the outside. As a result, the inside of the battery module 100 may not be filled with a sufficient amount of refrigerant, which could lead to a decrease in cooling performance.

[0086] Preferably, the refrigerant opening 410 connected to the inlet port 510 has its lower end positioned below the center with respect to the height of the battery cell stack 120, and the refrigerant opening 410 connected to the outlet port 516 has its upper end positioned above the center with respect to the height of the battery cell stack 120.

[0087] Furthermore, since the refrigerant opening 410 connected to the inlet port 510 extends vertically, the refrigerant flowing into the module frame 200 through the inlet port 510 can come into overall contact with the battery cell stack 120. Similarly, the refrigerant, in overall contact with the battery cell stack 120, can flow out of the module frame 200 through the outlet port 516. Therefore, the refrigerant can flow without any stagnant areas within the module frame 200, thereby improving cooling performance.

[0088] Furthermore, the refrigerant flowing in from the first refrigerant line 501 can flow along the inclined cover member 511 between the first refrigerant line 501 and the refrigerant opening 410. Therefore, the flow direction of the refrigerant does not change abruptly and it can flow into the inside of the battery module 100, thus reducing the possibility of bubbles forming inside the refrigerant.

[0089] Furthermore, since the cross-sectional area of ​​the inlet port 510 increases from the first refrigerant line 501 toward the refrigerant opening 410, the flow velocity of the refrigerant flowing in from the first refrigerant line 501 decreases inside the inlet port 510. Therefore, since the flow velocity of the refrigerant is reduced before it flows into the module frame 200 and comes into contact with the battery cell stack 120, abrupt changes in flow velocity inside the module frame 200 can be reduced. This reduces the possibility of bubbles forming inside the refrigerant due to abrupt changes in flow velocity, and increases the time the refrigerant is in contact with the battery cell stack 120, thereby improving cooling performance.

[0090] The expansion member 520 is a member that expands in volume when it reaches a predetermined temperature. If a thermal runaway phenomenon occurs in the battery cell 110, a high-temperature venting gas can be generated inside the battery module 100, and at the same time, the temperature of the refrigerant inside the battery module 100 can also rise. When the expansion member 520 reaches a predetermined temperature, it can expand in volume to close the refrigerant opening 410. More specifically, as shown in Figure 9(a), the expansion member 520 can be placed inside the inlet port 510 and the outlet port 516, respectively. If the expansion member 520 reaches a predetermined temperature, as shown in Figure 9(b), the expansion member 520 can expand in volume toward the internal space of the inlet port 510 and the outlet port 516, thereby closing the refrigerant opening 410.

[0091] Referring again to Figures 7 and 8, the expansion member 520 may include a main body 521 formed to surround the refrigerant opening 410 and a through-hole 522 formed for the refrigerant to flow in or out. In a typical environment, the refrigerant can flow into or out of the module frame 200 through the through-hole 522 of the expansion member 520.

[0092] When the expansion member 520 is positioned inside the inlet port 510 and outlet port 516, respectively, the main body 521 can be formed at an angle such that its cross-sectional area decreases as it moves away from the refrigerant opening 410. As shown in Figure 7, the main body 521 of the expansion member 520 is formed at an angle so as to protrude from the refrigerant opening 410, so that when the expansion member 520 comes into contact with the high-temperature refrigerant and / or venting gas generated inside the battery module 100, its volume can expand toward the cover members 511 of the inlet port 510 and outlet port 516. In other words, the expansion direction of the expansion member 520 is guided, so that the inlet port 510 and outlet port 516 can be effectively closed.

[0093] Furthermore, the main body 521 may include a plurality of micro-holes 523 formed to allow the refrigerant to penetrate the expansion member 520. As the high-temperature refrigerant and / or venting gas penetrates into the plurality of micro-holes 523, the penetration of the high-temperature refrigerant and / or venting gas into the foam layer 526 of the expansion member 520, which will be described later, can be facilitated. This allows for smooth volume expansion throughout the entire expansion member 520, rather than volume expansion occurring only in specific parts of the expansion member 520. On the other hand, the number of micro-holes 523 formed per unit area of ​​the main body 521 can be varied and modified as needed.

[0094] Figure 10 is a cross-sectional view of the expansion member.

[0095] Referring to Figure 10, the expanding member 520 includes a foamed layer 526 that foams and expands in volume when it reaches a predetermined temperature, a chemical-resistant layer 527 laminated on both sides of the foamed layer 526, and an adhesive layer 528 applied between the foamed layer 526 and the chemical-resistant layer 527 to bond the chemical-resistant layer 527 to the foamed layer 526.

[0096] The foamed layer 526 can be formed of a material that foams and expands in volume when in contact with a high-temperature refrigerant and / or venting gas. For example, the foamed layer 526 may contain materials equivalent to foamed polymers, and may include at least one of the following: silica gel, foamed silicone pads, polyurethane foam, and polypropylene.

[0097] As shown in Figure 10, the chemical-resistant layer 527 prevents the foam layer 526 from coming into contact with the refrigerant 600 under typical operating conditions. This prevents the foam layer 526 from absorbing the refrigerant 600 and from undergoing a chemical reaction with it. For example, the chemical-resistant layer 527 may include at least one of PVC, PET, nylon, PFA, PVDF, and PTFE.

[0098] On the other hand, the materials of the foam layer 526 and the chemical-resistant layer 527 are not limited to those described above, and may include a variety of foam materials that have high-temperature durability and chemical resistance.

[0099] The foamed layer 526 can foam and expand in volume once it reaches a first temperature. The chemical-resistant layer 527 can soften at a second temperature lower than the first temperature at which the foamed layer 526 foams. Furthermore, the chemical-resistant layer 527 can be thermally decomposed at a third temperature higher than the second temperature. In other words, the chemical-resistant layer 527 can soften at the second temperature before the foamed layer 526 reaches the first temperature at which it foams, and can be thermally decomposed and removed at the third temperature higher than the second temperature. Because the chemical-resistant layer 527 softens before reaching the first temperature, it can be thermally decomposed and removed immediately once it reaches the third temperature. As a result, the foamed layer 526 is prevented from coming into contact with the high-temperature refrigerant and / or venting gas by the chemical-resistant layer 527, and can foam upon contact with the high-temperature refrigerant and / or venting gas after the chemical-resistant layer 527 has been removed.

[0100] At this time, the third temperature at which the chemical-resistant layer 527 is thermally decomposed can be higher than or the same as the first temperature at which the foamed layer 526 is foamed. Since the chemical-resistant layer 527 is thermally decomposed at a temperature higher than or the same as the temperature at which the foamed layer 526 is foamed, it is possible to prevent the foamed layer 526 from undergoing a chemical reaction with the refrigerant and foaming until it reaches the temperature at which the foamed layer 526 is foamed.

[0101] Figure 11 is a conceptual diagram illustrating the operation of the venting section.

[0102] Referring again to Figures 3 and 11, the module frame 200 may include at least one venting section 210 formed at its upper end to discharge internal gases.

[0103] The venting section 210 may include a venting hole 211 that is open to allow internal gas to be discharged, and an opening 212 that closes the venting hole 211 when the pressure or temperature inside the module frame 200 is below a predetermined internal pressure or temperature, and opens the venting hole 211 when the pressure or temperature inside the module frame 200 reaches the predetermined internal pressure or temperature. For example, the opening 212 may include a bursting member 213 that is positioned corresponding to the venting section 210 and bursts when a predetermined internal pressure is reached, or is thermally decomposed when a predetermined internal temperature is reached. In Figure 11(a), the opening 212 is shown filled with the bursting member 213, and in Figure 11(b), it is shown with the bursting member 213 removed and the opening 212 open. However, the form of the bursting member 213 is not particularly limited as long as it can normally close the opening 212 and induce the discharge of internal gas while being removed when a predetermined internal pressure or temperature is reached. Furthermore, the pressure at which the rupture member 213 ruptures or the temperature at which it is thermally decomposed can be varied and modified depending on the type of refrigerant.

[0104] In the operating state of a typical battery module 100, the opening 212 is formed outside the venting hole 211, so the venting hole 211 is closed by the bursting member 213. If a thermal runaway phenomenon occurs in the battery cell 110 and gas is generated inside the battery module 100, the pressure inside the battery module 100 increases, causing the bursting member 213 to rupture and the venting hole 211 to be exposed to the outside. This allows the gas inside the battery module 100 to be discharged to the outside.

[0105] In particular, according to embodiments of the present invention, if a thermal runaway phenomenon occurs inside the battery module 100, the inlet port 510 and outlet port 516 are closed by the expansion member 520, so there is a possibility that a certain level or more of refrigerant 600 remains inside the battery module 100. At this time, the refrigerant 600 remaining inside the battery module 100 can cool the inside of the battery module 100 by absorbing the energy generated inside the battery module 100 and vaporizing. However, since the inlet port 510 and outlet port 516 of the battery module 100 are closed and the refrigerant 600 inside vaporizes, the internal pressure of the battery module 100 can rise. Therefore, when the internal pressure of the battery module 100 reaches a predetermined pressure, the battery module 100 is opened to the outside by the venting section 210, thereby reducing the internal pressure of the battery module 100. If the venting section 210 does not relieve the pressure inside the battery module 100, a problem may occur where refrigerant leaks from the module frame 200 and end plate 400 of the battery module 100, resulting in the battery module 100 not receiving the cooling effect of the refrigerant.

[0106] Therefore, if gas is generated inside the battery module 100 due to thermal runaway of the battery cells 110 and the internal pressure rises above a predetermined range, the venting section 210 can play a role in discharging the gas from inside the battery module 100. This prevents situations where the internal structure of the battery module 100 is exposed to the outside, thereby reducing its stability, while improving the stability of the battery module 100 and ensuring its full performance. Furthermore, since the cooling effect of the refrigerant 600 can be maintained for a longer period when thermal runaway occurs, the stability of the battery module 100 can be further improved.

[0107] Figure 12 is a perspective view of a battery pack including a battery module according to an embodiment of the present invention. Figure 13 is an exploded perspective view of the battery pack shown in Figure 12.

[0108] Referring to Figures 12 and 13, the battery pack 1000 includes a lower pack frame 1100 on which multiple battery modules 100 are mounted, and an upper pack frame 1200 located above the battery modules 100. Here, the lower pack frame 1100 and the upper pack frame 1200 can be joined to each other by welding or other methods to seal the inside of the battery pack 1000. Furthermore, the multiple battery modules 100 can be mounted together with various control and protection systems such as a BMS (Battery Management System) and a BDU (Battery Disconnect Unit) to form the battery pack 1000.

[0109] The lower pack frame 1100 includes the side pack frame 1150 and at least two internal beams 1110 formed on the bottom surface of the lower pack frame 1100. Here, the bottom surface of the lower pack frame 1100 and at least two internal beams 1110, and the bottom surface of the lower pack frame 1100 and the side pack frame 1150 can be joined to each other by methods such as welding.

[0110] Multiple battery modules 100 can be mounted in areas partitioned from each other by the side pack frame 1150 and at least two internal beams 1110. In other words, multiple battery modules 100 can be arranged in the area between the side pack frame 1150 and the internal beams 1110, and in the area located between adjacent internal beams 1110. More specifically, in the battery pack 1000, battery modules 100 can be arranged between a pair of adjacent internal beams 1110 and the side pack frame 1150.

[0111] As a result, multiple battery modules 100 are surrounded by at least two internal beams 1110 and side pack frames 1150, and each battery module 100 can be protected from external impacts.

[0112] The side pack frame 1150 is positioned around the periphery of the bottom surface of the lower pack frame 1100 and can extend upward (in the z-axis direction) from the bottom surface of the lower pack frame 1100. More specifically, it can extend upward from each periphery of the bottom surface of the lower pack frame 1100. Here, the upper end of the side pack frame 1150 can come into contact with the upper pack frame 1200. At this time, the upper end of the side pack frame 1150 and the upper pack frame 1200 can be joined to each other by welding or other methods to seal the inside of the battery pack 1000.

[0113] Multiple internal beams 1110 can be separated from each other. Here, the distance between adjacent internal beams 1110 can be the same as or greater than the size of the battery module 100.

[0114] Furthermore, the ends of the internal beam 1110 can contact the inner surface 1151 of the side pack frame 1150. More specifically, both ends of the internal beam 1110 can each contact the inner surface 1151 of the side pack frame 1150.

[0115] When multiple battery modules 100 are mounted on the lower pack frame 1100, each of the multiple battery modules 100 can be connected to a refrigerant line 500. Specifically, the first refrigerant line 501 is connected to the inlet port 510 of each of the multiple battery modules 100, and the second refrigerant line 502 is connected to the outlet port 516 of each of the multiple battery modules 100.

[0116] In this case, the refrigerant line 500 connecting the multiple battery modules 100 can be extended by passing over the top of the internal beam 1110. As another example, the refrigerant line 500 connecting the multiple battery modules 100 can also be extended by penetrating the internal beam 1110. However, the connection structure of the refrigerant line 500 connecting the multiple battery modules 100 is not limited to the above, and can be varied and modified in many ways depending on the arrangement of the multiple battery modules 100 and various components such as BMS (Battery Management System) and BDU (Battery Disconnect Unit) placed inside the battery pack 1000.

[0117] Figure 14 is a conceptual diagram illustrating the position of the expansion member in the battery pack.

[0118] Referring to Figure 14, the battery pack 1000 can be connected to external devices 2000, including a refrigerant storage unit 2100 and a heat exchanger 2200. For ease of explanation, Figure 14 only shows the components for refrigerant circulation, but a variety of components may be included depending on the device to which the battery pack 1000 is mounted.

[0119] The refrigerant stored in the refrigerant storage unit 2100 passes through the heat exchanger 2200 and then circulates along the refrigerant line 500 of the battery pack 1000. Specifically, the refrigerant that has passed through the heat exchanger 2200 flows into the inlet port 510 of each of the battery modules 100 through the first refrigerant line 501. After the refrigerant has flowed into the battery modules 100 cools them, it flows out into the second refrigerant line 502 through the outlet port 516 of each of the battery modules 100. The refrigerant that has flowed out into the second refrigerant line 502 flows back into the refrigerant storage unit 2100.

[0120] As shown in Figure 14, the expansion members 520 can be placed at the inlet ports 510 and outlet ports 516 of each of the multiple battery modules 100. The expansion members 520 placed at each of the inlet ports 510 and outlet ports 516 of the multiple battery modules 100 can close the inlet ports 510 and outlet ports 516 when a predetermined temperature is reached, thereby blocking the inflow of high-temperature refrigerant and / or venting gas into the refrigerant line 500.

[0121] Therefore, even if a runaway phenomenon occurs in one of the multiple battery modules 100, the expansion member 520 placed in the battery module 100 where the thermal runaway phenomenon occurred can prevent the venting gas generated in the battery module 100 from being discharged into the refrigerant line 500. This prevents the venting gas generated in one of the multiple battery modules 100 from propagating along the refrigerant line 500 to adjacent battery modules 100 and / or external devices 2000.

[0122] On the other hand, the battery module 100 and the battery pack 1000 containing the same according to the embodiment of the present invention can be applied to a variety of external devices 2000. In the embodiment shown in Figure 14, electric vehicles and hybrid vehicles are shown as examples of such devices, but the invention is not limited thereto. In other words, the present invention is applicable to a variety of devices that can use the battery module and the battery pack containing the same, and is applicable to means of transport such as electric bicycles and / or energy storage systems (ESS), which also fall within the scope of the present invention.

[0123] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto. Various modifications and improvements by those skilled in the art, utilizing the basic concepts of the present invention as defined in the following claims, also fall within the scope of the present invention. [Explanation of Symbols]

[0124] 100: Battery Module 110: Battery cell 120: Battery cell stack 200: Module Frame 210: Venting section 211: Venting Hall 212:Open part 213: Bursting member 300: Busbar Assembly 310: Busbar Frame 320: Bus bar 400: End plate 410: Refrigerant opening 500: Refrigerant line 506: Connecting member 510: Inflow port 511: Cover component 516: Leakage Port 520: Expansion member 521: Main body 522: Through-hole 523: Microholes 526: Foam layer 527: Chemical resistant layer 528: Adhesive layer 1000: Battery pack 1100: Lower pack frame 1110: Internal beam 1150: Side pack frame 1200: Upper pack frame 2000: External devices 2100: Refrigerant storage 2200: Heat exchanger

Claims

1. A battery cell stack in which multiple battery cells are stacked, A module frame that houses the aforementioned battery cell stack, The module frame has an inlet port through which refrigerant flows in, An outlet port from which the refrigerant flows out from inside the module frame, A battery module comprising an expandable member disposed inside the inlet port and the outlet port, respectively, which expands in volume when it reaches a predetermined temperature.

2. The module frame further includes end plates that close both open sides of the module frame and include refrigerant openings formed for the refrigerant to flow in or out, The battery module according to claim 1, wherein the expansion member expands to close the refrigerant opening when it reaches the predetermined temperature.

3. The inflow port is formed on an end plate located on either one of the two sides of the module frame. The battery module according to claim 2, wherein the outflow port is formed on an end plate located on one of the other sides of the module frame.

4. The upper end of the refrigerant opening is located above the center, with reference to the height of the battery cell stack. The battery module according to claim 2, wherein the lower end of the refrigerant opening is located below the center with respect to the height of the battery cell stack.

5. The battery module according to claim 4, wherein the length of the refrigerant opening from the upper end to the lower end is between 0.5 and 0.9 times the length of the end plate from the upper corner to the lower corner.

6. The aforementioned expansion member is A main body portion formed to surround the periphery of the refrigerant opening, The battery module according to claim 4, further comprising a through-hole formed to allow the refrigerant to flow in or out.

7. The battery module according to claim 6, wherein the main body is formed inclined such that its cross-sectional area decreases as it moves away from the refrigerant opening.

8. The battery module according to claim 6, wherein the main body includes a plurality of fine holes formed so that the refrigerant can penetrate the expansion member.

9. Each of the inlet port and the outlet port includes a cover member formed so as to be inclined downward on the surface facing the refrigerant opening. The battery module according to claim 2, wherein the cross-sectional area of ​​the inlet port and the outlet port decreases as you move from the top to the bottom.

10. The battery module according to claim 9, wherein the expansion member expands toward the internal space of the inlet port and the outlet port when expanded to close the refrigerant opening.

11. The aforementioned expansion member is A foamed layer that expands in volume when it reaches the first temperature, The battery module according to claim 1, comprising a chemical-resistant layer laminated on both sides of the foam layer and softening at a second temperature lower than the first temperature.

12. The battery module according to claim 11, wherein the chemical-resistant layer is thermally decomposed at a third temperature higher than the second temperature.

13. The battery module according to claim 12, wherein the third temperature is higher than or equal to the first temperature.

14. The battery module according to claim 11, wherein the foam layer comprises at least one of silica gel, foamed silicone pad, polyurethane foam, and polypropylene.

15. The battery module according to claim 11, wherein the chemical-resistant layer comprises at least one of PVC, PET, nylon, PFA, PVDF, and PTFE.

16. The battery module according to claim 1, wherein the module frame includes at least one venting portion formed at its upper end for discharging internal gases.

17. The aforementioned venting section is Vent holes that are opened to allow internal gases to be released, The battery module according to claim 16, further comprising: an opening that closes the venting holes when the pressure or temperature inside the module frame is below a predetermined internal pressure or temperature, and opens the venting holes when the pressure or temperature inside the module frame reaches the predetermined internal pressure or temperature.

18. The battery module according to claim 17, wherein the opening includes a rupture member that ruptures when it reaches a predetermined internal pressure or is thermally decomposed when it reaches a predetermined internal temperature.

19. The battery module according to claim 1, wherein the refrigerant includes an insulating refrigerant or a non-flammable refrigerant.

20. A battery pack comprising a plurality of battery modules according to any one of claims 1 to 19, Includes refrigerant lines connected to the inlet port and the outlet port, respectively. The expansion member, upon reaching the predetermined temperature, closes the inlet port and the outlet port to prevent the refrigerant from flowing into the refrigerant line, and is a battery pack.

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