WO2025188011A1 - Battery module and battery pack including same - Google Patents

Abstract

A battery module according to an embodiment of the present invention may comprise: a battery cell stack in which a plurality of battery cells are stacked; a module frame which accommodates the battery cell stack; an inlet port through which a refrigerant is introduced to the inside of the module frame; an outlet port through which the refrigerant is discharged from the inside of the module frame; and expansion members which are respectively disposed at the inlet port and the outlet port and expand in volume when a predetermined temperature is reached.

Description

Battery module and battery pack including same

Cross-citation with related application(s)

This application claims the benefit of priority to Korean Patent Application No. 10-2024-0032007, filed March 6, 2024, the entire contents of which are incorporated herein by reference.

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, which improve cooling efficiency to enhance cooling performance and can prevent venting gas emitted by a thermal runaway phenomenon occurring within the battery module from spreading to adjacent battery modules.

As technological developments and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. Accordingly, extensive research is being conducted on secondary batteries that can meet diverse needs.

Secondary batteries are attracting much attention not only as an energy source for mobile devices such as cell phones, digital cameras, and laptops, but also as a power source for power devices such as electric bicycles, electric cars, and hybrid electric vehicles.

Recently, as the need for large-capacity secondary battery structures has increased, including the use of secondary batteries as energy storage sources, the demand for battery packs with medium- to large-sized module structures that assemble battery modules in which a number of secondary batteries are connected in series/parallel is increasing.

Meanwhile, when configuring a battery pack by connecting multiple battery cells in series/parallel, it is common to configure a battery module composed of at least one battery cell and configure a battery pack by adding other components using at least one battery module.

The battery cells that make up these medium- to large-sized battery modules are composed of rechargeable secondary batteries. Therefore, these high-output, large-capacity secondary batteries generate a large amount of heat during the charging and discharging process. In this case, the heat from multiple battery cells accumulates in a small space, which can cause the temperature to rise rapidly and severely. In other words, battery modules with multiple battery cells stacked on top of each other and battery packs equipped with such battery modules can achieve high output, but it is difficult to remove the heat generated from the battery cells during charging and discharging. If the heat dissipation of the battery cells is not properly performed, the battery cells deteriorate quickly, shortening their lifespan and increasing the risk of explosion or fire.

Moreover, battery modules included in vehicle battery packs are frequently exposed to direct sunlight and may be subjected to high-temperature conditions, such as summer or desert environments. Furthermore, because multiple battery modules are densely packed together to increase vehicle range, flames or heat generated in one battery module can easily spread to neighboring modules, ultimately leading to ignition or explosion of the battery pack itself.

In addition, since the battery pack is composed of a structure in which multiple battery modules are combined, it is heavy and unsuitable for loading multiple batteries into a vehicle such as an automobile, so there is a need to improve the energy density.

Fig. 1 is a perspective view showing a conventional battery pack. Fig. 2 is an exploded perspective view of the battery pack of Fig. 1.

Referring to FIGS. 1 and 2, a conventional battery pack (10) includes a lower pack frame (11) on which a plurality of battery modules (1) are mounted, an upper pack frame (12) positioned above the battery modules (1), and an internal beam (13) that defines a location where the battery modules (1) are mounted within the battery pack (10).

In this way, when a battery module (1) is mounted inside a battery pack (10), the energy density of the battery pack (10) decreases due to the internal beam (13) that partitions between the battery modules (1), so there was a problem that a larger number of battery packs (10) had to be equipped to meet the efficiency required in a device, etc. In addition, there was a limit to the number of battery packs (10) that could be equipped in a device due to the weight of the battery pack (10). Therefore, in order to reduce the weight of the battery pack (10) and increase the energy density of the battery pack (10) at the same time, there was a need to mount a larger number of battery modules (1) inside the battery pack (10).

As illustrated in FIGS. 1 and 2, a conventional battery pack (10) is configured to house a plurality of battery modules (1). Accordingly, in the event that a thermal runaway phenomenon occurs in any one of the plurality of battery modules (1), there is a need for a structure or method capable of preventing the venting gas generated in the battery module (1) in which the thermal runaway phenomenon occurred from being transmitted to other battery modules (1) and the thermal runaway phenomenon from being transmitted to other battery modules (1).

In addition, since the conventional battery module (1) and battery pack (10) do not directly cool the battery cell stack provided in the battery module (1), a more effective method for improving cooling efficiency is needed.

The problem to be solved by the present invention is to provide a battery module and a battery pack including the same, which can improve cooling performance by improving the cooling efficiency of the battery module and prevent venting gas emitted by a thermal runaway phenomenon occurring within the battery module from spreading to adjacent battery modules.

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.

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 accommodating the battery cell stack, an inlet port through which a coolant is introduced into the interior of the module frame, an outlet port through which the coolant is discharged from the interior of the module frame, and an expansion member disposed in each of the inlet port and the outlet port and expanding in volume when a predetermined temperature is reached.

The module frame further includes an end plate that closes both open sides and includes a refrigerant opening formed for the refrigerant to flow in or out, and the expansion member can be expanded to close the refrigerant opening when the predetermined temperature is reached.

The inlet port may be formed in an end plate disposed on one of the two sides of the module frame, and the outlet port may be formed in an end plate disposed on the other of the two sides of the module frame.

The upper end of the coolant opening may be positioned above the center based on the height of the battery cell stack, and the lower end of the coolant opening may be positioned below the center based on the height of the battery cell stack.

The length from the upper end to the lower end of the refrigerant opening may be between 0.5 and 0.9 times the length from the upper edge to the lower edge of the end plate.

The above 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.

The above main body portion may be formed to be inclined so that the cross-sectional area decreases as it moves away from the refrigerant opening.

The above main body may include a plurality of micro holes formed to allow the refrigerant to penetrate the expansion member.

Each of the above inlet port and the above outlet port includes a cover member formed to be inclined downward on a surface opposite to the refrigerant opening, and the cross-sectional area of the above inlet port and the above outlet port may decrease as they go from the upper side to the lower side.

The above expansion member can expand toward the inner space of the inlet port and the outlet port when expanded to close the refrigerant opening.

The above-mentioned expansion member may include a foam layer that foams and expands in volume when a first temperature is reached, and a chemically resistant layer laminated on both sides of the foam layer that softens at a second temperature lower than the first temperature.

The above chemically resistant layer can be thermally decomposed at a third temperature higher than the second temperature.

The third temperature may be higher than or equal to the first temperature.

The foam layer may include at least one of silica gel, foamed silicone pad, polyurethane foam, and polypropylene.

The above chemical resistant layer may include at least one of PVC, PET, Nylon, PFA, PVDF and PTFE.

The above module frame may include at least one venting portion formed at the upper end to discharge gas inside.

The venting portion may include a venting hole that is opened to allow internal gas to be discharged, and an opening portion 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 a predetermined internal pressure or temperature.

The above opening may include a rupture member that ruptures when the predetermined internal pressure is reached or thermally decomposes when the predetermined internal temperature is reached.

The above refrigerant may include an insulating refrigerant or a non-flammable refrigerant.

A battery pack according to another embodiment of the present invention includes a plurality of battery modules according to the above-described embodiments, and includes a refrigerant line connected to each of the inlet port and the outlet port, and the expansion member can block the refrigerant from flowing into the refrigerant line by closing the inlet port and the outlet port when a predetermined temperature is reached.

A battery module and a battery pack including the same according to embodiments of the present invention can increase cooling efficiency by directly cooling a coolant to a battery cell, thereby increasing energy density.

In addition, since the venting gas released by the thermal runaway phenomenon occurring within the battery module can be prevented from spreading to the adjacent battery module, the stability of the battery module and the battery pack including the same can be improved even if a specific situation such as the thermal runaway phenomenon occurs.

In addition, since the cooling effect by the refrigerant can be maintained for a longer period of time in the event of a thermal runaway phenomenon, the stability of the battery module and the battery pack including the same can be further improved.

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.

Figure 1 is a perspective view showing a conventional battery pack.

Figure 2 is an exploded perspective view of the battery pack of Figure 1.

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.

FIG. 5 is a plan view showing one of the battery cells included in the battery cell stack of FIG. 4.

Figure 6 is a drawing of the battery module of Figure 3 viewed along the -x-axis direction on the yz plane.

Figure 7 is a drawing of the inlet port viewed along the -x-axis direction on the yz plane.

Figure 8 is a front view of the expansion member.

Figure 9 (a) is a drawing showing before the expansion member expands within the inlet port, and (b) is a drawing showing after the expansion member expands within the inlet port.

Figure 10 is a cross-sectional view of an expansion member.

Figure 11 is a conceptual diagram for explaining the operation of the venting section.

FIG. 12 is a perspective view of a battery pack including a battery module according to embodiments of the present invention.

Figure 13 is an exploded perspective view of the battery pack illustrated in Figure 12.

Figure 14 is a conceptual diagram illustrating the position where the expansion member is placed in the battery pack.

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.

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.

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.

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.

Additionally, 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.

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.

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.

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

Fig. 3 is a perspective view illustrating a battery module according to one embodiment of the present invention. Fig. 4 is an exploded perspective view of the battery module of Fig. 3. Fig. 5 is a plan view illustrating one of the battery cells included in the battery cell stack of Fig. 4.

Referring to FIGS. 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) accommodating the battery cell stack (120), an end plate (400) closing open sides of the module frame (200), an inlet port (510) formed in the end plate (400) arranged on one of the two sides of the module frame (200) so that a coolant can be introduced into the interior of the module frame (200), an outlet port (516) formed in the end plate (400) arranged on the other of the two sides of the module frame (200) so that a coolant can be discharged from the interior of the module frame (200), and an expansion member (520) disposed on the inlet port (510) and the outlet port (516), respectively, and expanding when a predetermined temperature is reached.

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

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

The battery cell (110) can be manufactured by bonding the periphery of the pouch case (114) while the electrode assembly (not shown) is housed in the pouch case (114). As another example, the battery cell (110) can be housed in a state where one side of the pouch case (114) is folded and the remaining sides are sealed.

The pouch case (114) of the laminate sheet may include an inner resin layer for sealing, a metal layer for preventing penetration of materials, and an outermost outer resin layer. Based on the electrode assembly inside the pouch case (114), the inner resin layer may be positioned at the innermost side, the outer resin layer may be positioned at the outermost side, and the metal layer may be positioned between the inner resin layer and the outer resin layer.

The outer resin layer may have excellent tensile strength and weather resistance relative to its thickness and may exhibit electrical insulation properties to protect the electrode assembly from the outside. The outer resin layer may include polyethylene terephthalate (PET) resin or nylon resin. The metal layer may prevent air, moisture, etc. from entering the pouch-type secondary battery. The metal layer may include aluminum (Al). The inner resin layers may be thermally bonded to each other by heat and/or pressure applied while the electrode assembly is embedded. The inner resin layer may include cast polypropylene (CPP) or polypropylene (PP).

A pouch case (114) may be divided into two parts, and a concave receiving portion in which an electrode assembly can be mounted may be formed in at least one of the two parts. Along the outer periphery of the receiving portion, the inner resin layers of the two parts of the pouch case (114) are bonded to each other, thereby sealing the pouch case (114), and a battery cell (110), which is a pouch-type battery, may be manufactured.

The battery cell (110) may be configured in multiple units, and the multiple battery cells (110) may be stacked so as to be electrically connected to each other to form a battery cell stack (120). In particular, as illustrated in FIG. 4, the multiple battery cells (110) may be stacked along a direction parallel to the y-axis while standing upright with one side of the cell body (113) facing each other. Accordingly, the electrode leads (111) may protrude in a direction perpendicular to the direction in which the battery cells (110) are stacked. That is, in the battery cell (110), one electrode lead (111) may protrude toward the x-axis direction, and the other electrode lead (111) may protrude toward the -x-axis direction. If the electrode leads (111) of the battery cell protrude only in one direction, the electrode leads (111) protrude in the x-axis direction or the -x-axis direction.

The module frame (200) may be intended to protect the battery cell stack (120) and electrical components connected thereto from external physical impact. The battery cell stack (120) and electrical components connected thereto may be accommodated in the internal space of the module frame (200).

The structure of the module frame (200) may vary. 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 (z-axis direction and -z-axis direction) and both side surfaces (y-axis direction and -y-axis direction) are integrated. The monoframe may be manufactured by extrusion molding.

However, the structure of the module frame (200) is not limited thereto, and in another embodiment, the module frame (200) may have a structure in which a U-shaped frame and an upper plate are combined. In this case, the U-shaped frame may have a lower surface and two side surfaces extending upward from both edges of the lower surface, and the upper plate may have a plate-like shape. In this case, each frame or plate constituting the U-shaped frame may be manufactured by press forming. In addition, the structure of the module frame (200) may be provided as an L-shaped frame structure in addition to a mono-frame or a U-shaped frame, and may also be provided as various structures not described in the above-described examples.

The module frame (200) may be open on both sides. More specifically, the module frame (200) may be provided in an open form along the longitudinal direction of the battery cell (110). In this case, the front and rear sides of the battery cell stack (120) may not be covered by the module frame (200). The front and rear sides of the battery cell stack (120) may be covered by the bus bar assembly (300) and the end plate (400), and through this, the front and rear sides of the battery cell stack (120) may be protected from external physical impacts, etc.

The battery module (100) may include a busbar assembly (300) positioned on each of one side and the other side of the battery cell stack (120). Specifically, the busbar assembly (300) may be positioned on each of the two directions in which the electrode leads (111) of the battery cells (110) included in the battery cell stack (120) protrude. The busbar assembly (300) may electrically connect the battery cells (110) constituting the battery cell stack (120) in series or in parallel. The busbar assembly (300) may each include a busbar frame (310), a busbar (320), and a terminal busbar.

The busbar frame (310) may be positioned on one side of the battery cell stack (120) to cover one side of the battery cell stack (120) and simultaneously guide the connection between the battery cell stack (120) and an external device. The busbar frame (310) may be positioned on the front (x-axis direction) and the rear (-x-axis direction) of the battery cell stack (120).

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

The busbar frame (310) may include an electrically insulating material. The busbar frame (310) may limit contact between the busbar (320) and other parts of the battery cells (110) other than the part where the busbar is connected to the electrode lead (not shown), thereby preventing electrical short circuits from occurring.

The bus bar (320) is mounted on one side of the bus bar frame (310) and may be used to electrically connect the battery cell stack (120) or battery cells (110) and an external device circuit. The bus bar (320) is positioned on the bus bar frame (310), and the bus bar assembly (300) is covered by the end plate (500) of FIG. 4, so that it can be protected from external impacts, etc., and the deterioration of the battery's durability due to external moisture, etc. can be minimized.

The bus bar (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 be bent after passing through slits formed in the bus bar frame (310) and connected to the bus bar (320). The battery cells (110) constituting the battery cell stack (120) can be connected in series or in parallel by the bus bar (320). There is no particular limitation on the connection method between the electrode leads (111) and the bus bar (320), and for example, welding may be applied.

Meanwhile, although not shown in FIGS. 3 and 4, the battery module (100) may be provided with a terminal bus bar. The terminal bus bar may include a first terminal bus bar and a second terminal bus bar, and the first terminal bus bar and the second terminal bus bar may have different polarities.

The terminal bus bar may be electrically connected to the bus bar (320) or the electrode lead to electrically connect one battery module (100) to another battery module (100). At least a portion of the terminal bus bar may be exposed to the outside of the end plate (400) to connect one battery module (100) to another external battery module (100), and the end plate (400) may be provided with a terminal bus bar opening (not shown) for this purpose. The terminal bus bar may be connected to another battery module (100) or a BDU (Battery Disconnect Unit) through a portion exposed through the terminal bus bar opening, and may form an HV (High voltage) connection with them.

The end plate (400) can be formed to cover the battery cell stack (120) by positioning it on both open sides (in the x-axis direction and the -x-axis direction) of the module frame (200) and closing the open sides of the module frame (200). This end plate (400) can physically protect the battery cell stack (120) and other electrical components from external impact.

The end plate (400) may include a refrigerant opening (410) formed for the introduction or discharge of refrigerant. The refrigerant opening (410) is an opening provided in the end plate (400) and is a hole penetrating the end plate (400). Accordingly, even when the end plate (510) is mounted, the refrigerant may be introduced from the outside to the inside of the module frame (200) or may be discharged from the inside to the outside of the module frame (200) through the refrigerant opening (410). The refrigerant opening (410) may be covered by an inlet port (510) or an outlet port (516) described below and may be connected to a first refrigerant line (501) or a second refrigerant line (502), respectively.

The coolant opening (410) may be a hole formed to extend in the vertical direction (z-axis direction and -z-axis direction). The upper end of the coolant opening (410) may be located above the center with respect to the height of the battery cell stack (120). The lower end of the coolant 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 coolant opening (410) to the upper end of the coolant opening (410) may be greater than or equal to the length from the upper edge of the end plate (400) to the upper end of the coolant opening (410). Additionally, 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 edge of the end plate (400) to the lower end of the refrigerant opening (410). More specifically, the length from the upper end of the refrigerant opening (410) to the lower end may be between 0.5 and 0.9 times the length from the upper edge of the end plate (400) to the lower edge.

The above-described refrigerant may be directly introduced into the module frame (200). As the refrigerant is introduced into the module frame (200), it may directly contact the battery cell stack (120), busbar assembly (300), or other electrical components accommodated in the module frame (200), thereby receiving heat generated therefrom. However, as described above, the refrigerant is not limited to directly contacting the components accommodated in the module frame (200). That is, the refrigerant may also indirectly contact the components accommodated in the module frame (200). For example, the refrigerant may cool the components accommodated in the module frame (200) by flowing inside the module frame (200) along the refrigerant path formed inside the module frame (200).

The above refrigerant may be a fluid. Since the refrigerant may come into direct contact with the battery cell stack (120), busbar assembly (300), or other electrical components within the battery module (100), it must be electrically insulated. Accordingly, the refrigerant may be an insulating refrigerant. As an example, the refrigerant may be an insulating oil. However, the type of the refrigerant is not limited by the above. For example, since it is necessary that the refrigerant not ignite even when exposed to a high-temperature environment within the battery module (100), the refrigerant may be a non-flammable refrigerant.

That is, in the case of the present 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 receiving heat from them. Therefore, compared to indirectly cooling the battery module using a heat sink or the like in a conventional battery module, the battery module (100) according to the embodiments of the present invention can have improved cooling efficiency through direct cooling, thereby extending the life of the battery.

Meanwhile, although not shown in FIG. 4, the battery module (100) may further include a sealing assembly. The sealing assembly may be formed to cover the battery cell stack (120) by being positioned on both open sides of the module frame (200). That is, the sealing assembly may be positioned between the end plate (400) and the battery cell stack (120), thereby isolating the open sides of the module frame (200) from the external environment. Specifically, the sealing assembly may serve to seal the coolant so that it does not leak to the outside when the coolant is injected into the module frame (200).

Fig. 6 is a drawing of the battery module of Fig. 3 viewed along the -x-axis direction on the yz plane. Fig. 7 is a drawing of the inlet port viewed along the -x-axis direction on the yz plane. Fig. 8 is a front view of the expansion member. Fig. 9 (a) is a drawing showing the expansion member before expansion within the inlet port, and (b) is a drawing showing the expansion member after expansion within the inlet port.

Referring to FIGS. 6 to 9, the battery module (100) includes an inlet port (510) and an outlet port (516) for circulating a coolant into the interior of the module frame (200), and an expansion member (520) disposed inside each of the inlet port (510) and the outlet port (516). The inlet port (510) may be formed in an end plate (400) disposed on one of both surfaces of the module frame (200) so that the coolant may be introduced into the interior of the module frame (200), and the outlet port (516) may be formed in an end plate (400) disposed on the other of both surfaces of the module frame (200) so that the coolant may be discharged from the interior of the module frame (200). Meanwhile, a detailed description of the expansion member (520) will be described later.

The above refrigerant circulates through a refrigerant line (500) connected to an inlet port (510) and an outlet port (516), respectively. More specifically, the refrigerant moves from a refrigerant storage (2100) described below through a heat exchanger (2200) and the refrigerant line (500), then flows into the module frame (200) through the inlet port (510), flows out of the module frame (200) through the outlet port (516), and then is returned to the refrigerant storage (2100) through the refrigerant line (500). Meanwhile, 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 FIGS. 6 and 7, and the description of the same or corresponding content as the inlet port (510) will be omitted below.

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

The inlet port (510) may have a shape corresponding to the refrigerant opening (410) in order to cover the refrigerant opening (410). As described above, since the refrigerant opening (410) is a hole extending in the vertical direction, the inlet port (510) may also have a shape extending in the vertical direction. In addition, the inlet port (510) may include a cover member (511) for covering the refrigerant opening (410) of the end plate (400). The cover member (511) may be formed to be inclined downward on a surface facing the refrigerant opening (410). Accordingly, the cross-sectional area of the inlet port (510) may decrease from the upper side to the lower side (-z-axis direction).

Considering the shape and position of the coolant opening (410) extending vertically as described above, the coolant opening (410) connected to the inlet port (510) may have a lower end positioned lower than the center based on the height of the battery cell stack (120). That is, the lower end of the coolant opening (410) connected to the inlet port (510) may be positioned close to the lower edge of the end plate (400). In addition, the coolant opening (410) connected to the outlet port (516) may have an upper end positioned higher than the center based on the height of the battery cell stack (120). That is, the upper end of the coolant opening (410) connected to the outlet port (516) may be positioned close to the upper edge of the end plate (400).

If the lower end of the refrigerant opening (410) connected to the inlet port (510) is located above the center based on the height of the battery cell stack (120), there is a possibility that bubbles will form inside the refrigerant because the refrigerant will flow into the inside of the battery module (100) as if it were falling from a high position. Such bubbles will hinder the cooling effect.

In addition, if the upper end of the coolant opening (410) connected to the outlet port (516) is located lower than the center based on the height of the battery cell stack (120), the coolant flowing into the inside of the battery module (100) is filled only up to the height of the outlet port (516) and then escapes to the outside, so the inside of the battery module (100) is not filled with a sufficient amount of coolant, which may result in a decrease in cooling performance.

It is preferable that the coolant opening (410) connected to the inlet port (510) has a lower end positioned lower than the center based on the height of the battery cell stack (120), and that the coolant opening (410) connected to the outlet port (516) has an upper end positioned higher than the center based on the height of the battery cell stack (120).

In addition, since the refrigerant opening (410) connected to the inlet port (510) extends in the vertical direction, the refrigerant flowing into the module frame (200) through the inlet port (510) can come into contact with the battery cell stack (120) as a whole. Similarly, the refrigerant in contact with the battery cell stack (120) as a whole can flow out of the module frame (200) through the outlet port (516). Therefore, since the refrigerant can flow without stagnating within the module frame (200), the cooling performance can be improved.

In addition, 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, since the refrigerant can flow into the interior of the battery module (100) without the flow direction of the refrigerant changing abruptly, the possibility of bubbles forming inside the refrigerant can be reduced.

In addition, since the cross-sectional area of the inlet port (510) increases as it moves from the first refrigerant line (501) toward the refrigerant opening (410), the refrigerant flowing in from the first refrigerant line (501) has a reduced flow rate inside the inlet port (510). Therefore, since the flow rate of the refrigerant is reduced in advance before it flows into the interior of the module frame (200) and comes into contact with the battery cell stack (120), a rapid change in flow rate inside the module frame (200) can be reduced. Accordingly, the possibility of bubbles forming inside the refrigerant due to a rapid change in flow rate can be reduced, and the time that the refrigerant comes into contact with the battery cell stack (120) can be increased, so that the cooling performance can be improved.

The expansion member (520) is a member that expands in volume when a predetermined temperature is reached. If a thermal runaway phenomenon of the battery cells (110) occurs, high-temperature venting gas may be generated inside the battery module (100), and at the same time, the temperature of the coolant inside the battery module (100) may also rise. The expansion member (520) may expand in volume to close the coolant opening (410) when the predetermined temperature is reached. More specifically, as shown in (a) of FIG. 9, the expansion member (520) may be respectively disposed inside the inlet port (510) and the outlet port (516). If the expansion member (520) reaches a predetermined temperature, as shown in (b) of FIG. 9, the expansion member (520) may expand in volume toward the inner space of the inlet port (510) and the outlet port (516) to close the coolant opening (410).

Referring again to FIGS. 7 and 8, the expansion member (520) may include a main body (521) formed to surround the periphery of the refrigerant opening (410) and a through hole (522) formed to allow refrigerant to flow in or out. In a typical environment, the refrigerant may flow into the interior of the module frame (200) or flow out from the module frame (200) through the through hole (522) of the expansion member (520).

When the expansion member (520) is respectively disposed inside the inlet port (510) and the outlet port (516), the main body (521) may be formed to be inclined so that the cross-sectional area decreases as it gets farther away from the refrigerant opening (410). As illustrated in FIG. 7, since the main body (521) of the expansion member (520) is formed to be inclined so as to protrude from the refrigerant opening (410), when the expansion member (520) comes into contact with the high-temperature refrigerant and/or venting gas generated inside the battery module (100), the volume may expand toward the cover member (511) of the inlet port (510) and the outlet port (516). That is, since the expansion direction of the expansion member (520) is guided, the inlet port (510) and the outlet port (516) can be effectively closed.

In addition, the main body (521) may include a plurality of micro holes (523) formed to allow the refrigerant to penetrate the expansion member (520). Since the high-temperature refrigerant and/or venting gas penetrates the micro holes (523) of the plurality of micro holes (523), the high-temperature refrigerant and/or venting gas can easily penetrate the foam layer (526) of the expansion member (520) described later. Accordingly, the volume expansion can smoothly occur throughout the entire expansion member (520), rather than only in a specific portion of the expansion member (520). Meanwhile, the number of the plurality of micro holes (523) formed per area of the main body (521) can be variously changed and modified as needed.

Figure 10 is a cross-sectional view of an expansion member.

Referring to FIG. 10, the expansion member (520) includes a foam layer (526) that expands in volume by foaming when a predetermined temperature is reached, a chemical-resistant layer (527) laminated on both sides of the foam layer (526), and an adhesive layer (528) applied between the foam layer (526) and the chemical-resistant layer (527) to adhere the chemical-resistant layer (527) to the foam layer (526).

The foam layer (526) may be formed of a material that foams and expands in volume when contacted with a high-temperature refrigerant and/or venting gas. For example, the foam layer (526) may include materials corresponding to foamed polymers, such as at least one of silica gel, foamed silicone pad, polyurethane foam, and polypropylene.

As illustrated in FIG. 10, the chemical resistant layer (527) prevents the foam layer (526) from contacting the refrigerant (600) in a normal operating environment. Accordingly, the foam layer (526) can be prevented from absorbing the refrigerant (600) and from causing a chemical reaction with the refrigerant (600). For example, the chemical resistant layer (527) can include at least one of PVC, PET, Nylon, PFA, PVDF, and PTFE.

Meanwhile, the materials of the foam layer (526) and the chemical-resistant layer (527) are not limited to those described above, and may include various foam materials having high-temperature durability and chemical resistance.

The foam layer (526) can be foamed and expand in volume when it reaches a first temperature. The chemical resistant layer (527) can be softened at a second temperature lower than the first temperature at which the foam layer (526) is foamed. Additionally, the chemical resistant layer (527) can be thermally decomposed at a third temperature higher than the second temperature. That is, the chemical resistant layer (527) can be softened at the second temperature before the first temperature at which the foam layer (526) is foamed is reached, and can be thermally decomposed and removed at a third temperature higher than the second temperature. Since the chemical resistant layer (527) is softened before reaching the first temperature, it can be thermally decomposed and removed immediately when it reaches the third temperature. Accordingly, the foam layer (526) is prevented from contacting the high-temperature refrigerant and/or venting gas by the chemical-resistant layer (527), and can be foamed upon contacting the high-temperature refrigerant and/or venting gas after the chemical-resistant layer (527) is removed.

At this time, the third temperature at which the chemical resistant layer (527) undergoes thermal decomposition may be higher than or equal to the first temperature at which the foamed layer (526) is foamed. Since the chemical resistant layer (527) undergoes thermal decomposition at a temperature higher than or equal to the temperature at which the foamed layer (526) is foamed, the foamed layer (526) can be prevented from foaming by chemically reacting with the refrigerant until the temperature at which the foamed layer (526) is foamed is reached.

Figure 11 is a conceptual diagram for explaining the operation of the venting section.

Referring again to FIG. 3 and FIG. 11, the module frame (200) may include at least one venting portion (210) formed at the upper portion to discharge internal gas.

The venting portion (210) may include a venting hole (211) that is open to allow internal gas to escape, and an opening portion (212) that closes the venting hole (211) when the pressure or temperature inside the module frame (200) is below a predetermined internal pressure or a predetermined internal temperature, and opens the venting hole (211) when the pressure or temperature inside the module frame (200) reaches a predetermined internal pressure or a predetermined internal temperature. For example, the opening portion (212) may be positioned to correspond to the venting portion (210) and may include a rupture member (213) that ruptures when a predetermined internal pressure is reached or thermally decomposes when a predetermined internal temperature is reached. In (a) of FIG. 11, the opening portion (212) is illustrated in a form filled with the rupture member (213), and in (b) of FIG. 11, the rupture member (213) is removed, and the opening portion (212) is illustrated in an open form. However, there is no particular limitation on the form of the rupture member (213), as long as it can close the opening (212) normally and induce the discharge of internal gas by being removed when a predetermined internal pressure or a predetermined internal temperature is reached. In addition, the pressure at which the rupture member (213) ruptures or the temperature at which it thermally decomposes can be varied and modified in various ways depending on the type of refrigerant.

In the operating state of a typical battery module (100), the opening (212) is formed outside the venting hole (211), so that the venting hole (211) is closed by the rupture member (213). When a thermal runaway phenomenon of the battery cells (110) occurs and gas is generated inside the battery module (100), the pressure inside the battery module (100) increases, causing the rupture member (213) to rupture, exposing the venting hole (211) to the outside. Accordingly, the gas inside the battery module (100) can be discharged to the outside.

In particular, according to embodiments of the present invention, when a thermal runaway phenomenon occurs inside the battery module (100), the inlet port (510) and the outlet port (516) are closed by the expansion member (520), so that a certain level or more of refrigerant (600) may remain inside the battery module (100). At this time, the refrigerant (600) remaining inside the battery module (100) may cool the inside of the battery module (100) by receiving energy generated inside the battery module (100) and vaporizing. However, since the inlet port (510) and the outlet port (516) of the battery module (100) are closed and the refrigerant (600) inside is vaporized, the internal pressure of the battery module (100) may increase. Accordingly, when the internal pressure of the battery module (100) reaches a predetermined pressure, the battery module (100) can be opened to the outside by the venting portion (210), thereby reducing the pressure inside the battery module (100). If the pressure inside the battery module (100) is not relieved by the venting portion (210), a coolant leak may occur in the module frame (200) and end plate (400) of the battery module (100), which may cause a problem in that the cooling effect by the coolant cannot be received inside the battery module (100).

Accordingly, when gas is generated due to thermal runaway of the battery cells (110) inside the battery module (100) and the internal pressure increases above a predetermined range, the venting portion (210) can discharge the gas inside the battery module (100). Accordingly, the stability of the battery module (100) can be improved and the full performance of the battery module (100) can be secured while preventing a situation in which the internal configuration of the battery module (100) is exposed to the outside, thereby lowering the stability. In addition, when a thermal runaway phenomenon occurs, the cooling effect by the refrigerant (600) can be maintained for a longer period of time, thereby further improving the stability of the battery module (100).

Fig. 12 is a perspective view of a battery pack including a battery module according to embodiments of the present invention. Fig. 13 is an exploded perspective view of the battery pack illustrated in Fig. 12.

Referring to FIGS. 12 and 13, a battery pack (1000) includes a lower pack frame (1100) on which a plurality of battery modules (100) are mounted, and an upper pack frame (1200) positioned above the battery modules (100). Here, the lower pack frame (1100) and the upper pack frame (1200) may be joined to each other by a method such as welding, thereby sealing the inside of the battery pack (1000). In addition, the plurality of battery modules (100) may be mounted together with various control and protection systems such as a BMS (Battery Management System) and a BDU (Battery Disconnect Unit) to form a battery pack (1000).

The lower pack frame (1100) includes a 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 the at least two internal beams (1110), and the bottom surface of the lower pack frame (1100) and the side pack frame (1150) may be joined to each other by a method such as welding.

A plurality of battery modules (100) may be mounted in an area partitioned from each other by a side pack frame (1150) and at least two internal beams (1110). In other words, the plurality of battery modules (100) may be respectively disposed in an area between the side pack frame (1150) and the internal beams (1110), and an area positioned between adjacent internal beams (1110). More specifically, in the battery pack (1000), the battery modules (100) may be disposed between a pair of internal beams (1110) that are positioned adjacent to each other among the plurality of internal beams (1110) and the side pack frame (1150).

Accordingly, the plurality of battery modules (100) are surrounded by at least two internal beams (1110) and side pack frames (1150), so that each battery module (100) can be protected from external impact.

The side pack frame (1150) may be arranged at an edge of the bottom surface of the lower pack frame (1100) and may extend upward (in the z-axis direction) from the bottom surface of the lower pack frame (1100). More specifically, it may extend upward from each edge of the bottom surface of the lower pack frame (1100). Here, the upper end of the side pack frame (1150) may be in 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) may be joined to each other by a method such as welding, thereby sealing the inside of the battery pack (1000).

The plurality of inner beams (1110) may be spaced apart from each other. Here, the distance at which the adjacent inner beams (1110) are spaced apart may be equal to or greater than the size of the battery module (100).

Additionally, the end portion of the inner beam (1110) may be in contact with the inner surface (1151) of the side pack frame (1150). More specifically, both ends of the inner beam (1110) may be in contact with the inner surface (1151) of the side frame (1150), respectively.

When a plurality of battery modules (100) are mounted on the lower pack frame (1100), each of the plurality of battery modules (100) can be connected to a refrigerant line (500). Specifically, a first refrigerant line (501) can be connected to an inlet port (510) of each of the plurality of battery modules (100), and a second refrigerant line (502) can be connected to an outlet port (516) of each of the plurality of battery modules (100).

At this time, the refrigerant line (500) connecting the plurality of battery modules (100) may extend through the upper portion of the inner beam (1110). As another example, the refrigerant line (500) connecting the plurality of battery modules (100) may extend through the inner beam (1110). However, the connection structure of the refrigerant line (500) connecting the plurality of battery modules (100) is not limited to the above-described structure, and may be variously changed and modified depending on the arrangement of various components such as the plurality of battery modules (100) and the BMS (Battery Management System), BDU (Battery Disconnect Unit) arranged inside the battery pack (1000).

Figure 14 is a conceptual diagram illustrating the position where the expansion member is placed in the battery pack.

Referring to FIG. 14, the battery pack (1000) may be connected to an external device (2000) including a coolant storage (2100) and a heat exchanger (2200). For convenience of explanation, only components for circulating coolant are illustrated in FIG. 13, but various components may be included depending on the device to which the battery pack (1000) is mounted.

The refrigerant stored in the refrigerant storage (2100) passes through the heat exchanger (2200) and then circulates along the refrigerant line (500) of the battery pack (1000). Specifically, the refrigerant passing through the heat exchanger (2200) flows into the inlet port (510) of each of the plurality of battery modules (100) through the first refrigerant line (501). The refrigerant flowing into the plurality of battery modules (100) cools the battery modules (100) and then flows out through the second refrigerant line (502) through the outlet port (516) of each of the plurality of battery modules (100). The refrigerant flowing out through the second refrigerant line (502) flows back into the refrigerant storage (2100).

As illustrated in FIG. 14, the expansion member (520) may be disposed at the inlet port (510) of each of the plurality of battery modules (100) and the outlet port (516) of each of the plurality of battery modules (100). The expansion member (520) disposed at each of the inlet port (510) and the outlet port (516) of the plurality of battery modules (100) may close the inlet port (510) and the outlet port (516) when a predetermined temperature is reached, thereby blocking the inflow of high-temperature refrigerant and/or venting gas into the refrigerant line (500).

Accordingly, even if a thermal runaway phenomenon occurs in one of the plurality of battery modules (100), the venting gas generated in the battery module (100) can be prevented from being discharged into the refrigerant line (500) by the expansion member (520) disposed in the battery module (100) where the thermal runaway phenomenon occurs. Accordingly, the venting gas generated in one of the plurality of battery modules (100) can be prevented from being transmitted to an adjacent battery module (100) and/or an external device (2000) along the refrigerant line (500).

Meanwhile, the battery module (100) and the battery pack (1000) including the same according to embodiments of the present invention can be applied to various external devices (2000). In the embodiment illustrated in FIG. 14, electric vehicles and hybrid vehicles are shown as examples of such devices, but are not limited thereto. That is, the present invention can be applied to various devices that can use the battery module and the battery pack including the same, and for example, can be applied to transportation means such as electric bicycles and/or energy storage systems (ESS), which also fall within the scope of the present invention.

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]

100: Battery module

110: Battery cell

120: Battery cell stack

200: Module Frame

210: Venting Department

211: Venting Hall

212: Opening

213: Rupture member

300: Busbar assembly

310: Busbar frame

320: Busbar

400: End Plate

410: Refrigerant opening

500: Refrigerant line

506: Absence of connection

510: Inlet port

511: Cover absence

516: Outlet port

520: Expansion member

521: Main body

522: Penetration

523: Micro hole

526: Foam layer

527: Chemical-resistant layer

528: Adhesive layer

1000: Battery Pack

1100: Lower pack frame

1110: Inner beam

1150: Side pack frame

1200: Upper pack frame

2000: External devices

2100: Refrigerant storage

2200: Heat exchanger

Claims (20)

A battery cell stack in which multiple battery cells are stacked; A module frame accommodating the above battery cell stack; An inlet port through which refrigerant flows into the interior of the above module frame; an outlet port through which the refrigerant flows out from the inside of the module frame; and A battery module comprising an expansion member positioned inside each of the inlet port and the outlet port and expanding when a predetermined temperature is reached. In the first paragraph, Further comprising an end plate that closes both open sides of the above module frame and includes a refrigerant opening formed for the refrigerant to flow in or out; A battery module in which the expansion member expands to close the refrigerant opening when the predetermined temperature is reached. In the second paragraph, The above inlet port is formed on an end plate placed on either side of the module frame, A battery module wherein the above-mentioned outlet port is formed on an end plate disposed on the other side of the module frame. In the second paragraph, The upper end of the above refrigerant opening is located above the center based on the height of the battery cell stack, A battery module, wherein the lower end of the above refrigerant opening is located lower than the center based on the height of the battery cell stack. In paragraph 4, A battery module, wherein the length from the upper end of the refrigerant opening to the lower end is between 0.5 and 0.9 times the length from the upper edge to the lower edge of the end plate. In paragraph 4, The above expansion member, A main body formed to surround the periphery of the refrigerant opening; and A battery module comprising a through hole formed to allow the refrigerant to flow in or out. In paragraph 6, A battery module in which the main body is formed to be inclined so that the cross-sectional area decreases as it moves away from the refrigerant opening. In paragraph 6, A battery module, wherein the main body includes a plurality of microscopic holes formed to allow the refrigerant to penetrate the expansion member. In the second paragraph, Each of the above inlet port and the above outlet port includes a cover member formed to be inclined downward on a surface opposite to the refrigerant opening, A battery module, wherein the cross-sectional area of the inlet port and the outlet port decreases from the top to the bottom. In paragraph 9, A battery module wherein the expansion member expands toward the inner space of the inlet port and the outlet port when expanded, thereby closing the refrigerant opening. In the first paragraph, The above expansion member, A foam layer that foams and expands in volume when it reaches the first temperature; and A battery module comprising a chemically resistant layer laminated on both sides of the foam layer and softened at a second temperature lower than the first temperature. In Article 11, A battery module wherein the above chemically resistant layer is thermally decomposed at a third temperature higher than the second temperature. In paragraph 12, The battery module wherein the third temperature is higher than or equal to the first temperature. In Article 11, A battery module, wherein the foam layer comprises at least one of silica gel, foamed silicone pad, polyurethane foam, and polypropylene. In the first paragraph, A battery module wherein the chemical resistant layer comprises at least one of PVC, PET, Nylon, PFA, PVDF and PTFE. In the first paragraph, A battery module, wherein the module frame includes at least one venting portion formed at the upper end to discharge internal gas. In Article 16, The above venting part, Venting holes open to allow the gases inside to escape; and A battery module comprising an opening portion that closes the venting hole when the pressure or temperature inside the module frame is below a predetermined internal pressure or a predetermined internal temperature, and opens the venting hole when the pressure or temperature inside the module frame reaches the predetermined internal pressure or the predetermined internal temperature. In Article 17, A battery module, wherein the opening includes a rupture member that ruptures when the predetermined internal pressure is reached or thermally decomposes when the predetermined internal temperature is reached. In the first paragraph, The above refrigerant is a battery module including an insulating refrigerant or a non-flammable refrigerant. A battery pack comprising a plurality of battery modules according to Article 1, Includes a refrigerant line connected to each of the inlet port and the outlet port, A battery pack, wherein the expansion member closes the inlet port and the outlet port when a predetermined temperature is reached, thereby blocking the refrigerant from flowing into the refrigerant line.