Battery pack with improved fire prevention performance

Abstract

A battery pack according to one embodiment of the present invention includes: a cell module assembly including a battery cell stack in which a plurality of battery cells are stacked; a pack case that houses the cell module assembly in its internal space; and a fire extinguishing unit that can supply a fire extinguishing agent into the pack case to extinguish a fire in the battery cell when a thermal event occurs in the battery cell, and the pack case includes at least one drain hole in at least one of the lengthwise edge and widthwise edge of the bottom surface of the pack case.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0179747 dated December 20, 2022 and Korean Patent Application No. 10-2022-0179748 dated December 20, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery pack, and more particularly to a battery pack that is configured to facilitate drainage of moisture generated within the battery pack under normal conditions.

[0003] The present invention also relates to a battery pack, and more particularly to a battery pack that allows a fire extinguishing agent (fire extinguishing liquid) to remain in the battery pack for a long period of time when a thermal event occurs. [Background technology]

[0004] Currently commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Of these, lithium secondary batteries are attracting attention due to their advantages of almost no memory effect compared to nickel-based secondary batteries, free charging and discharging, very low self-discharge rate, and high energy density.

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

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

[0007] These secondary batteries are widely used not only in small devices such as portable electronic devices but also in medium- to large-sized devices such as electric vehicles and energy storage systems (ESS), and their usage is rapidly increasing. In addition, there has been a recent trend toward using residential battery packs for storing power. Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides a battery pack that is configured to facilitate drainage of moisture generated within the battery pack under normal conditions.

[0009] Another object of the present invention is to provide a battery pack that allows a fire extinguishing agent (fire extinguishing liquid) to remain within the battery pack for a long period of time when a thermal event occurs.

[0010] However, the technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below. [Means for solving the problem]

[0011] A battery pack according to one embodiment of the present invention includes: a cell module assembly including a battery cell stack in which a plurality of battery cells are stacked; a pack case that houses the cell module assembly in an internal space; and a fire extinguishing unit that can supply a fire extinguishing agent into the pack case to extinguish a fire in the battery cell when a thermal event occurs in the battery cell, and the pack case may include at least one drain hole in at least one of a lengthwise edge and a widthwise edge of a bottom surface of the pack case.

[0012] The drain port may further include a thermal expansion member positioned at the drain port, the thermal expansion member expanding in volume at a predetermined temperature or higher to seal the drain port.

[0013] The thermal expansion member may further include a thermal expansion member connecting portion disposed a predetermined distance from an inner surface of the drain outlet and disposed across a cross section of the drain outlet to fix the thermal expansion member.

[0014] The thermal expansion member may have a groove at at least one end thereof, the thermal expansion member coupling part may be bar-shaped, and the thermal expansion member coupling part may be fixedly coupled to the groove of the thermal expansion member.

[0015] The thermal expansion member coupling may be located at at least one of the inlet and outlet of the drain opening.

[0016] The thermal expansion member may have a pin shape that is arranged along the path of the drain hole.

[0017] The thermal expansion member and the interior surface of the drain port may be coaxially arranged.

[0018] The thermal expansion member may contact and surround at least a portion of an interior surface of the drain outlet.

[0019] The thermal expansion member may be made of a polymer material.

[0020] The thermal expansion member may be any one selected from the group consisting of PDMS (Poly-Di-Methyl-Siloxane), polyvinyl acetate, polystyrene, butyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, and combinations thereof.

[0021] The thermal expansion member may include a core of heat resistant material positioned within the thermal expansion member along the length of the thermal expansion member.

[0022] The fire extinguishing unit may be a fire extinguishing tank located above the cell module assembly and covering the upper surface of the pack case.

[0023] The extinguishing agent may be in a liquid state.

[0024] The height of the bottom surface of the drain hole may decrease from the inside to the outside of the pack case.

[0025] The cross section of the drain hole may have a tapered shape that increases in size from the inside to the outside of the pack case.

[0026] The internal space of the pack case may further include a plurality of protruding surfaces protruding upward from the bottom surface and a first drainage channel between the plurality of protruding surfaces, and the plurality of protruding surfaces may be arranged in a line along the length and width directions of the bottom surface of the pack case.

[0027] The protruding surface may include: a top surface located at the center of the protruding surface and on which the cell module assembly is placed; and an inclined surface formed radially from the top surface, the inclined surface decreasing in height from the top surface to the edge of the protruding surface.

[0028] The top surface may have a circular plate shape, and the radially inclined surfaces may be equiangularly arranged with respect to the center of the protruding surface.

[0029] The first drainage channels may be arranged parallel to at least one of the lengthwise edge and the widthwise edge of the bottom surface of the pack case.

[0030] The bottom surface of the drain outlet may have the same height as or lower than the first drain channel.

[0031] The internal space of the pack case may further include second drainage channels arranged on the longitudinal and widthwise edges of the bottom surface of the pack case, and the second drainage channels may have the same height as or lower than the first drainage channel.

[0032] The bottom surface of the drain outlet may have the same height as or a lower height than the second drain channel.

[0033] The pack case may further include a plate-shaped partition wall disposed across the pack case, and the internal space of the pack case may be divided into a storage space for the cell module assembly and a storage space for the electrical connection unit based on the partition wall, and the plurality of protruding surfaces and the first drainage channel may be provided in at least one of the storage space for the cell module assembly and the storage space for the electrical connection unit.

[0034] The pack case may further include an auxiliary case made of a metal material for temporarily housing the cell module assembly, the cell module assembly being housed in the auxiliary case, the auxiliary case being placed on the top surface of the protruding surface of the pack case, and the auxiliary case may include at least one opening in a bottom surface thereof.

[0035] The opening may be provided on an edge of the bottom surface of the auxiliary case or on a corner of the bottom surface of the auxiliary case.

[0036] The battery pack may be provided in a plurality of pieces, and the plurality of battery packs may be connected to each other by mechanical and / or electrical connections.

[0037] The plurality of battery packs may be stackable in a vertical direction.

[0038] The plurality of battery packs may be electrically connected in series so that the voltages of the plurality of battery packs can be variably realized.

[0039] The plurality of battery packs may be electrically connected in parallel so that the storage capacities of the plurality of battery packs can be variably realized.

[0040] To achieve the above object, an energy storage device according to another aspect of the present invention includes one or more of the above-described battery packs according to the present invention. [Effects of the Invention]

[0041] According to one aspect of the present invention, a battery pack can be provided that ensures drainage and safety of the battery cells so that moisture does not affect the battery cells when moisture occurs inside the battery pack due to condensation, snow, rain, etc. under normal conditions.

[0042] According to one aspect of the present invention, in the event of a fire or thermal runaway in the cell module assembly, the thermal expansion member expands in volume above a predetermined temperature to seal the drain outlet. This prevents the fire extinguishing agent (fire extinguishing liquid) from being discharged to the outside of the pack case through the drain outlet when the fire extinguishing agent (fire extinguishing liquid) is supplied into the pack case. This allows the fire extinguishing agent (fire extinguishing liquid) to remain in the cell module assembly 100 inside the pack case for a long time. This means that the fire or thermal runaway in the cell module assembly can be more stably extinguished.

[0043] Furthermore, according to one aspect of the present invention, there is no need to design a special waterproof and dustproof structure.

[0044] Furthermore, according to one aspect of the present invention, by stacking a plurality of battery packs of the same type, it is possible to provide products with a variety of voltages and / or storage capacities.

[0045] In addition, various other additional effects may be achieved by various embodiments of the present invention. Such various effects of the present invention will be described in detail in each embodiment, or a description of effects that can be easily understood by a person skilled in the art will be omitted. [Brief explanation of the drawings]

[0046] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical concept of the present invention, and therefore the present invention should not be interpreted as being limited solely to the matters depicted in the drawings. [Figure 1] 1 is an exploded perspective view showing a schematic configuration of a battery pack according to an embodiment of the present invention; [Figure 2] 2 is a diagram illustrating a configuration for discharging a fire extinguishing agent in the battery pack of FIG. 1. [Figure 3] FIG. 10 is a perspective view schematically illustrating the configuration of a battery pack according to another embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view taken along line A4-A4′ in FIG. 3. [Figure 5] FIG. 10 is an exploded perspective view schematically illustrating the configuration of a battery pack according to yet another embodiment of the present invention. [Figure 6] FIG. 6 is a perspective view of a cell module assembly included in the battery pack of FIG. 5. [Figure 7] 6 is a perspective view of a blocking member included in the battery pack of FIG. 5. FIG. [Figure 8] FIG. 6 is a perspective view of a pack case included in the battery pack of FIG. 5. [Figure 9] 9 is a diagram illustrating a case in which the cell module assembly of FIG. 8 is housed in a pack case. [Figure 10] 9 is a diagram illustrating a case in which the cell module assembly of FIG. 8 is housed in a pack case. [Figure 11] FIG. 9 is a top view of the pack case of FIG. 8. [Figure 12] FIG. [Figure 13] FIG. [Figure 14] 1 illustrates an embodiment of a thermal expansion member. [Figure 15] 1 illustrates an embodiment of a thermal expansion member. [Figure 16] FIG. 6 is a perspective view of a fire extinguishing tank included in the battery pack of FIG. 5. [Figure 17]FIG. 17 is a perspective cross-sectional view of the fire tank of FIG. 16. [Figure 18] FIG. 18 is a perspective view of a battery pack in which all of the components of the battery packs described above with reference to FIGS. 5 to 17 are combined. [Figure 19] FIG. 19 is a perspective view schematically showing the battery pack of FIGS. 1 to 18. [Figure 20] 20 is a view showing an embodiment in which the pack cases shown in FIG. 19 are stacked in different numbers. [Figure 21] 20 is a view showing an embodiment in which the pack cases shown in FIG. 19 are stacked in different numbers. DETAILED DESCRIPTION OF THE INVENTION

[0047] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and phrases used in the specification and claims should not be interpreted in a limited manner based on their ordinary or dictionary meanings, but should be interpreted in a manner that is consistent with the technical concept of the present invention, based on the principle that an inventor can appropriately define the concept of a term in order to best describe his or her invention.

[0048] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can replace them at the time of this application.

[0049] In order to clearly explain the present invention, parts unnecessary for the explanation have been omitted and the same reference numerals have been used throughout the specification to refer to the same or similar components.

[0050] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are exaggerated to clearly show multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0051] Furthermore, when a layer, film, region, plate, or other part is said to be "above" another part, this includes not only the case where it is "directly above" that part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. Furthermore, being "above" a reference part means being located above or below the reference part, and does not necessarily mean being "above" in the direction opposite to gravity.

[0052] Furthermore, throughout the specification, when a part is said to "comprise" a certain element, this does not mean that other elements are excluded and that other elements may also be included, unless specifically stated to the contrary.

[0053] Also, throughout the specification, "on a plane" means when the subject part is viewed from above, and "on a cross section" means when the subject part is cut vertically and viewed from the side.

[0054] FIG. 1 is an exploded perspective view schematically showing the configuration of a battery pack according to one embodiment of the present invention.

[0055] Referring to FIG. 1, a battery pack according to the present invention includes a cell module assembly 100, a pack case 300, and a fire tank 400.

[0056] The cell module assembly 100 may include one or more battery cells 110. Here, each battery cell 110 may represent a secondary battery. A secondary battery may include an electrode assembly, an electrolyte, and a battery case. In particular, the battery cells 110 included in the cell module assembly 100 may be pouch-type secondary batteries. However, other types of secondary batteries, such as cylindrical batteries and prismatic batteries, may also be used in the cell module assembly 100 of the present invention.

[0057] A plurality of secondary batteries may be stacked on one another to form the cell module assembly 100. That is, the cell module assembly 100 may be formed in the form of a battery cell stack. For example, a plurality of battery cells 110 may be stacked in a horizontal arrangement (X-axis direction) with each battery cell 110 standing vertically (Z-axis direction in the drawing). Each battery cell 110 may have an electrode lead, which may be located at both ends or one end of each battery cell 110. A secondary battery with electrode leads protruding in both directions is called a bidirectional cell, and a secondary battery with electrode leads protruding in one direction is called a unidirectional cell. FIG. 1 illustrates a bidirectional cell. However, the present invention is not limited to the specific type or shape of such a secondary battery, and various types of secondary batteries known at the time of filing of the present invention may be used in the cell module assembly 100 of the present invention.

[0058] The pack case 300 may be configured to have an empty space formed therein to accommodate the cell module assemblies 100. For example, the pack case 300 may be configured in a box shape as shown in Fig. 1. The box-shaped pack case 300 may be integrally molded or may be manufactured by connecting at least one surface to an adjacent surface.

[0059] The fire tank 400 may contain a fire extinguishing agent. In particular, the fire tank 400 may have an internal space and may contain the fire extinguishing agent in the internal space. For example, as shown in FIG. 1, the fire tank 400 may include a lower tank 410 and an upper cover 420. Here, the lower tank 410 may be configured in the form of a box with an open top, and may provide a space in which the fire extinguishing agent can be contained. The upper cover 420 may be configured to cover the open top of the lower tank 410 and seal the fire extinguishing agent-containing space of the lower tank 410.

[0060] The fire tank 400 may be housed inside the pack case 300. In particular, the fire tank 400 may be disposed above the cell module assembly 100 in the internal space of the pack case 300.

[0061] According to this embodiment of the present invention, a thermal event in the cell module assembly 100 can be more easily controlled by discharging the extinguishing agent from the fire tank 400 located on the upper side of the cell module assembly 100. In particular, the extinguishing agent discharged from the fire tank 400 can easily move downward by gravity. Therefore, the heat and fire in the cell module assembly 100 can be more easily extinguished by the extinguishing agent.

[0062] In particular, when the cell module assembly 100 includes a plurality of battery cells 110 arranged horizontally, i.e., in the left-right direction (X-axis direction), as shown in Fig. 1, when fire extinguishing agent is discharged from the fire tank 400 located above, the fire extinguishing agent can be easily supplied to all of the battery cells 110. Therefore, according to this embodiment, a thermal event can be more effectively suppressed for the entire cell module assembly 100.

[0063] The fire extinguishing tank 400 may be configured to discharge a fire extinguishing agent toward the cell module assembly 100 when heat is applied from the cell module assembly 100. This will be described in more detail with reference to FIG.

[0064] FIG. 2 is a diagram schematically illustrating a configuration for discharging a fire extinguishing agent in the battery pack of FIG.

[0065] 2, a fire tank 400 is located above the cell module assembly 100. Among the multiple battery modules stacked in the left-right direction (e.g., the X-axis direction in the drawing), a thermal event such as overheating, fire, or thermal runaway may occur in a specific battery cell 110, as indicated by A1. In this case, heat generated in the battery cell 110 may be applied to the fire tank 400, for example, the portion indicated by A2 in FIG. 2. Then, a fire extinguishing agent may be discharged from the fire tank 400, as indicated by arrow A3.

[0066] In particular, the fire tank 400 may be configured so that at least a portion thereof melts due to heat applied from the cell module assembly 100. For example, in the configuration of Fig. 2, the portion of the fire tank 400 indicated by A2 may melt due to heat. Then, the extinguishing agent may be discharged through the melted portion as indicated by arrow A3.

[0067] For this purpose, at least a portion of the fire tank 400 may be made of a material that can melt due to heat applied from the cell module assembly 100. For example, the fire tank 400 may be entirely made of a plastic material. In particular, the fire tank 400 may be made in the form of a plastic injection molding.

[0068] The fire tank 400 may be configured to melt due to heat or venting gas emitted from the battery cell 110. For example, if thermal runaway occurs in the battery cell 110 and venting gas is emitted, the venting gas may be at a high temperature above a certain temperature. The fire tank 400 may be configured with a material and / or shape that can be melted by such high-temperature venting gas. Alternatively, if thermal runaway occurs in the battery cell 110, the battery cell 110 may be at a higher temperature than normal even if no venting gas is emitted. The fire tank 400 may be configured with a material and / or shape that can be melted by heat applied from the battery cell 110 in such an abnormally high temperature state.

[0069] In particular, the fire tank 400 may be configured so that the base plate 411 melts due to the high temperature of heat and / or gas generated during an event in the battery cell 110. In this case, the fire extinguishing agent may flow into the melted portion at the bottom of the fire extinguishing tank 400 and be discharged downward. Therefore, the fire extinguishing agent may be quickly injected toward the cell module assembly 100.

[0070] According to this embodiment of the present invention, the extinguishing agent is injected in a manner that melts the projectile, effectively suppressing the thermal event inside the battery pack while minimizing the thermal event propagation between the battery cells 110.

[0071] The fire tank 400 may contain a liquid fire extinguishing agent. In this case, the fire extinguishing agent may be referred to as a fire extinguishing liquid. For example, the fire tank 400 may contain water or other coolants as a fire extinguishing agent. The fire tank 400 may also contain antifreeze as a fire extinguishing agent. In particular, when a battery pack is used in cold seasons such as winter or in cold regions such as polar regions, the fire tank 400 may contain antifreeze as a fire extinguishing agent, which does not easily freeze even at low temperatures. Furthermore, in the case of a residential battery pack, which may be located outdoors, antifreeze may be provided as a fire extinguishing agent.

[0072] The fire tank 400 may be configured such that the thickness of the base plate 411 varies depending on the position, which will be described in more detail with reference to FIGS.

[0073] Figure 3 is a perspective view schematically illustrating the configuration of a battery pack according to another embodiment of the present invention. For ease of explanation, some components are shown transparently in Figure 3. Also, Figure 4 is a cross-sectional view taken along line A4-A4' in Figure 3. Regarding various embodiments included in this specification, including this embodiment, detailed descriptions of parts that are the same or similar to those described in other embodiments will be omitted, and differences will be mainly described.

[0074] 3 and 4, the fire extinguishing tank 400 may include a base plate 411 and a side wall 412. Here, the side wall 412 may be configured to protrude upward from the edge of the base plate 411. The bottom and sides of the fire extinguishing tank 400 are defined by the base plate 411 and the side wall 412, forming a space capable of holding an extinguishing agent. At this time, the top of the fire extinguishing tank 400 may be sealed by the pack case 300. That is, as shown in FIG. 4, the pack case 300 includes a lower case 300a and an upper case 300b, and the top of the fire extinguishing tank 400 is covered by the upper case 300b, thereby allowing the extinguishing agent to be held inside the fire extinguishing tank 400. Alternatively, the fire extinguishing tank 400 may be configured to include an upper cover 420, as shown in FIG. 1, to seal the top of the extinguishing agent holding space.

[0075] In the fire tank 400 having the base plate 411, the base plate 411 may be formed to have different thicknesses in different parts. In particular, the fire tank 400 may be configured to have a thinner thickness in a specific part, such as the part indicated by reference numeral 411a in Figures 3 and 4. For example, the base plate 411 of the fire tank 400 may be formed in the form of a plastic injection molding having an overall thickness of 1 mm, but the part indicated by reference numeral 411a may be configured to have a thickness of 0.5 mm.

[0076] In particular, the thinned portion of the base plate 411 of the fire tank 400 can function as the weak portion 411a. That is, when the temperature rises in the cell module assembly 100, the weak portion 411a can be damaged first. When the weak portion 411a is damaged, the extinguishing agent stored inside the fire tank 400 can be discharged to the cell module assembly 100 side through the weak portion 411a.

[0077] A plurality of fragile portions 411a may be provided. The fragile portions 411a may have, for example, a narrow width and a long length. That is, they may have a linear shape and be arranged parallel to one edge of the fire extinguisher tank 400, and the fragile portions 411a may be arranged parallel to each other.

[0078] According to this embodiment, when venting gas or a fire occurs due to thermal runaway in the cell module assembly 100, there is no need to provide a separate structure for injecting a fire extinguisher such as coolant. Therefore, a structure for injecting a fire extinguisher into the battery pack can be realized with a simple structure. Furthermore, in this structure, when an event occurs, the fire extinguisher can be discharged through the thin, weakened portion 411a, so the portion from which the fire extinguisher is discharged can be specified in advance.

[0079] 4, a plurality of fragile portions 411a may be provided in one fire tank 400. Furthermore, the plurality of fragile portions 411a may be arranged on the base plate 411 of the fire tank 400 at predetermined intervals along the stacking direction of the cell module assemblies 100. For example, a plurality of battery cells 110 may be stacked in the left-right direction (X-axis direction) in the cell module assembly 100, and a plurality of fragile portions may also be arranged in the left-right direction at intervals on the base plate 411 of the fire tank 400 located on top of the cell module assembly 100.

[0080] In particular, the fire extinguishing tank 400 may be configured such that a weakened portion 411a having a relatively small thickness is located in the center portion between horizontally stacked cells.

[0081] For example, in the configuration of FIG. 4, two battery cells 110, B1 and B2, are arranged adjacent to each other in the left-right direction on the left side of the cell module assembly 100. In this case, the leftmost weak portion 411a among the multiple weak portions 411a may be arranged between B1 and B2 in the left-right direction. In other words, the weak portion 411a is located above B1 and B2 in the vertical direction (Z-axis direction), but is located between B1 and B2 in the horizontal direction (X-axis direction). Furthermore, for battery cells 110 other than B1 and B2, one weak portion 411a may be configured to be located in the space between every two adjacent battery cells 110 in the horizontal direction.

[0082] According to this embodiment of the present invention, when a thermal event occurs in a specific battery cell 110 and heat is applied to the upper vulnerable portion 411a, the vulnerable portion 411a may be damaged. Then, the extinguishing agent may be discharged through the damaged vulnerable portion 411a and flow into the space between adjacent battery cells 110 as indicated by the arrows in FIG. 4 .

[0083] Therefore, this embodiment can more effectively prevent the transmission of a thermal event between battery cells 110. Furthermore, this embodiment of the present invention can inject a fire extinguishing agent intensively around a battery cell 110 where a thermal event such as overheating or ignition has occurred, thereby enabling more effective cooling and fire extinguishing operations. Therefore, this embodiment can inject a fire extinguishing agent at the right time and place when a fire or other event occurs inside the battery without the need for any other components other than the fire tank 400.

[0084] FIG. 5 is an exploded perspective view schematically showing the configuration of a battery pack according to another embodiment of the present invention.

[0085] Referring to FIG. 5, the battery pack includes a cell module assembly 100, a blocking member 200, a pack case 300, a fire tank 400, an outer cover 500, and an electrical connection unit 600.

[0086] In FIG. 5, the cell module assembly 100 may also include a plurality of battery cells 110 (see FIG. 1) stacked in a manner that they are arranged horizontally (e.g., along the X-axis direction in the drawing) with each battery cell 110 standing vertically (e.g., along the Z-axis direction in the drawing). In this case, the length direction of the battery cells 110 is, for example, along the Y-axis direction in the drawing. For ease of understanding, the illustration of the battery cells 110 is omitted in FIG. 5. If the battery cells 110 are, for example, pouch-type or prismatic battery cells, the battery cells 110 are arranged alongside (parallel to) the blocking member 200.

[0087] FIG. 6 is a perspective view of a cell module assembly 100 included in the battery pack of FIG.

[0088] For reference, in order to more clearly show the components included in the cell module assembly 100, Fig. 6 shows the remaining components excluding the plurality of battery cells 110. The plurality of battery cells 110 may be conventional pouch-type battery cells or prismatic battery cells.

[0089] 6, a pair of bus bar housings 130 are disposed on the front and rear surfaces of a stack of multiple battery cells 110. Each of the bus bar housings 130 is disposed in a direction perpendicular to the length direction of the battery cells 110 (for example, in the X-axis direction in the drawing).

[0090] A pair of end plates 120 are provided on both ends of the outermost portion of the stack of the plurality of battery cells 110. The end plates 120 are arranged parallel to the battery cells 110. The pair of end plates 120 connects the pair of bus bar housings 130, respectively.

[0091] At least one strap 140 may be included on each of the upper and lower sides between the pair of end plates 120, connecting the pair of end plates 120. The strap 140 strengthens the binding of the cell module assembly 100. More specifically, it strengthens the binding of the pair of end plates 120 and the stack of multiple battery cells 110 disposed therebetween. This makes it possible to prevent the stack of multiple battery cells 110 from becoming misaligned.

[0092] Other details regarding the cell module assembly 100 overlap with those described with reference to FIG. 1, so please refer to what was described above in connection with FIG.

[0093] Meanwhile, as shown in Fig. 5, a predetermined number of battery cells 110 may be grouped and stored. Also, as shown in Figs. 5 to 7, a blocking member 200 is provided between a group of a predetermined number of battery cells 110 and an adjacent group of a predetermined number of battery cells 110.

[0094] 7 is a perspective view of the blocking member 200 included in the battery pack of FIG. 5. The blocking member 200 may be configured to be interposed between adjacent battery cells 110 to block heat. For example, if a thermal event occurs in some battery cells 110 and heat or high-temperature venting gas is generated, the blocking member 200 can suppress or block the generated heat or gas from being transferred to adjacent battery cells 110. In addition, the blocking member 200 can play a role in blocking flames, sparks, etc. that are emitted from a specific battery cell 110.

[0095] The blocking member 200 has a substantially plate-like shape. The blocking member 200 may be configured in the form of a plate that stands vertically. The blocking member 200 may have a height that is the same as or similar to the height of the battery cells 110 that also stand vertically. The height of the blocking member 200 may be smaller or larger than the height of the battery cells 110.

[0096] The number of blocking members 200 may correspond to the number of battery cells. As described above, the blocking members 200 may be stacked together with the battery cells 110 to form the cell module assembly 100.

[0097] According to this embodiment of the present invention, in a battery pack including a plurality of battery cells 110, the insulating member 200 can effectively prevent thermal runaway propagation between cells.

[0098] The blocking member 200 may also have a large triple-layer structure. For example, a pair of swelling pads 220 is provided on each side of a support plate 210. The support plate 210 maintains the shape and rigidity of the blocking member 200 and blocks flames or sparks erupting from the battery cells 110 between the battery cells 110. The support plate 210 may be made of, for example, a metal material. The swelling pads 220 reduce the pressure applied to the battery cells 110 by the support plate 210 when the battery cells 110 expand. The swelling pads 220 may be made of, for example, a silicone material or a soft plastic material.

[0099] Meanwhile, the support plate 210 includes a plurality of through holes 230 formed to penetrate the support plate 210 in the vertical direction, and the plurality of through holes 230 are arranged along the length direction of the support plate 210 .

[0100] When a fire extinguishing agent (fire extinguishing liquid) is poured into the cell module assembly 100 from the fire tank 400 located above the cell module assembly 100, the fire extinguishing agent (fire extinguishing liquid) also enters the plurality of through-holes 230. In other words, the fire extinguishing agent (fire extinguishing liquid) remains in the plurality of through-holes 230, thereby more effectively cooling and extinguishing the battery cell 110 in which a thermal event has occurred.

[0101] The plurality of through holes 230 may be open on both the upper and lower surfaces of the support plate 210. Alternatively, the plurality of through holes 230 may be open only on the upper surface and closed on the lower surface so that the extinguishing agent (extinguishing liquid) can remain for a longer period of time within the through holes 230. In the former case, if the support plate 210 of the blocking member 200 is disposed so as to be in close contact with the lower inner surface of the pack case 300, the extinguishing agent (extinguishing liquid) can remain for a longer period of time within the through holes 230, as in the latter case.

[0102] Fig. 8 is a perspective view of the pack case 300 included in the battery pack of Fig. 5. Figs. 9 and 10 are diagrams illustrating the case where the cell module assembly 100 of Fig. 8 is housed in the pack case 300.

[0103] 8, the pack case 300 may be configured in a box shape. The box-shaped pack case 300 may be integrally molded or may be manufactured by combining at least one surface with an adjacent surface.

[0104] The pack case 300 includes at least one vent port 320. A filter is attached to the vent port 320.

[0105] When a thermal event occurs in a battery cell 110 housed inside the pack case 300, venting gas generated in the battery cell 110 can be discharged through the vent port 320. The venting gas discharged from the vent port 320 can pass through the space between the pack case 300 and the outer cover 500 (see FIG. 5 ) and be discharged to the outside of the outer cover 500.

[0106] The internal space of the pack case 300 is roughly divided into two storage spaces based on the partition wall 380. One is a space S1 in which the cell module assembly 100 is stored, and the other is a space S2 in which an electrical connection unit including a connector 610 is stored.

[0107] The space S2 on the bottom surface of the pack case 300 includes a connector through-hole 370 into which the connector 610 of the battery pack stacked in the lower layer can be inserted for electrical connection between the vertically stacked battery packs, as will be described later. This allows the connector 610 of the battery pack to be connected to the connector 610 of the battery pack stacked in the lower layer. Similarly, in the same manner, the connector 610 of the battery pack to be connected to the connector 610 of the battery pack stacked in the upper layer.

[0108] 9 and 10, the cell module assembly 100 shown in FIG. 6 may be housed in the internal space of an auxiliary case 310 and then attached to the pack case 300. By temporarily housing the cell module assembly 100 in the internal space of the auxiliary case 310 and then finally housing it in the pack case 300, the rigidity of the cell module assembly 100 can be enhanced and misalignment of the stack of multiple battery cells 110 in the cell module assembly 100 can be prevented. The auxiliary case 310 may be made of, for example, metal or stainless steel.

[0109] A drainage structure for a battery pack in a normal state according to an embodiment of the present invention will be described below.

[0110] Fig. 11 is a top view of the pack case 300 of Fig. 8. Figs. 12 and 13 are partial enlarged views of the pack case 300. For reference, Figs. 11 to 13 do not show the auxiliary case 310 shown in Figs. 9 and 10.

[0111] First, condensed water may form in the internal space of the pack case 300. In some cases, moisture from snow and rain may enter the interior of the pack case 300 and condense into water, which may then reside in the internal space of the pack case 300. If the water in the internal space of the pack case 300 accumulates on the bottom of the pack case 300 due to gravity, it may affect the performance of the battery cells and electrical connection units 600 housed inside the pack case 300. To prevent such problems, the battery pack according to an embodiment of the present invention has a structure that can easily drain moisture (humidity, water, etc.) that may normally reside inside the pack case 300. In an embodiment of the present invention, the following components related to the drainage structure are included.

[0112] As shown in FIG. 11, the bottom surface of the pack case 300 includes a plurality of protruding surfaces 330. The protruding surfaces 330 are arranged in a line along at least one of the length and width directions of the pack case 300. FIG. 12 shows an enlarged view of the protruding surfaces 330. The protruding surfaces 330 protrude upward from the bottom surface of the pack case 300. That is, the protruding surfaces 330 are higher than other portions of the bottom surface of the pack case 300. First drainage channels 340 are disposed between the protruding surfaces 330. The first drainage channels 340 are at the same height as or lower than the edges of the protruding surfaces 330. The height of the first drainage channels 340 may decrease from the center of the bottom surface of the pack case 300 toward the edges. Alternatively, the height of the first drainage channels 340 may be generally flat.

[0113] In addition, a second drainage channel 350 may be further arranged along the edge in the length direction (e.g., the Y-axis direction in the drawing) and / or the edge in the width direction (e.g., the X-axis direction in the drawing) of the bottom surface of the pack case 300. The first drainage channel 340 and the second drainage channel 350 are connected to each other. The first drainage channel 340 has the same height as or is higher than the second drainage channel 350. The height of the bottom surface of the drainage opening 360, which will be described later, is the same height as or lower than the heights of the first drainage channel 340 and the second drainage channel 350. The drainage opening 360 may have a tapered shape (a truncated cone or a square pyramid shape), for example.

[0114] Water in the interior space of pack case 300 flows along protruding surface 330 on the bottom surface of pack case 300 to first drainage channel 340 and is then discharged to the outside through drainage port 360 located on the edge of the bottom surface of pack case 300. Alternatively, water that has flowed into first drainage channel 340 moves along second drainage channel 350 and is then discharged to the outside through drainage port 360.

[0115] According to one embodiment of the present invention, the protruding surface 330 includes a top surface 331 located at the center of the protruding surface 330 and an inclined surface 332 formed radially from the top surface 331. The cell module assembly 100 is placed on the top surface 331. The cell module assembly 100 may be placed in direct contact with the top surface 331. Meanwhile, when the cell module assembly 100 is housed in an auxiliary case 310 as described below, the auxiliary case 310 housing the cell module assembly 100 may be placed in direct contact with the top surface 331. The top surface 331 may be circular as shown. However, the present invention is not limited thereto, and any shape that can support the cell module assembly 100 may suffice.

[0116] As shown in the cross section taken along line A6-A6' in Figure 12, the height of the inclined surfaces 332 decreases from the top surface 331 to the edge of the protruding surface 330. The inclined surfaces 332 are formed radially from the center of the protruding surface 330 (e.g., the top surface 331). The inclined surfaces 332 may be arranged equiangularly from the center of each of the radially formed protruding surfaces 330.

[0117] Furthermore, according to one embodiment of the present invention, a plurality of protruding surfaces 330 are provided. The plurality of protruding surfaces 330 are arranged in a line along the length and width directions of the bottom surface of the pack case 300, in a so-called lattice (checkerboard) arrangement. The first drainage channels 340 disposed between the protruding surfaces 330 are arranged parallel to the lengthwise edges and / or widthwise edges of the bottom surface of the pack case 300.

[0118] In addition, the pack case 300 includes at least one drain hole 360 ​​on the edge of its bottom surface. That is, the pack case 300 may include one drain hole 360. Alternatively, the pack case 300 may include a plurality of drain holes 360 arranged in a line or arranged on each of the four sides of the pack case 300, i.e., the front, rear, left, and right sides. The position and number of the drain holes 360 may be modified and changed to suit various environments in which the present invention is embodied.

[0119] FIG. 13 shows an enlarged cross section of the drain hole 360 ​​in a front view of the pack case 300. The cross section of the drain hole 360 ​​increases in size from the inside to the outside of the pack case 300. For example, if the top surface of the drain hole 360 ​​is a truncated cone (i.e., a truncated cone), the inner diameter of the cross section of the drain hole 360 ​​increases from the inside to the outside of the pack case 300. In this case, the bottom surface of the drain hole 360 ​​slopes and decreases in height from the inside to the outside of the pack case 300. This allows water inside the pack case 300 to be smoothly discharged to the outside through the drain hole 360.

[0120] 9 and 10, the cell module assembly 100 may be housed in an auxiliary case 310 to protect the battery cells and facilitate storage, and then housed together with the auxiliary case 310 in the pack case 300. In this case, the auxiliary case 310 also includes at least one opening 310a on the bottom and / or edge of the bottom of the auxiliary case 310. FIG. 10 shows a case where the opening 310a is provided on the edge of the bottom of the auxiliary case 310. More specifically, the opening 310a may be provided in the bottom of the auxiliary case 310, may be disposed along the edge of the bottom of the auxiliary case 310, or may be disposed at a corner of the bottom of the auxiliary case 310. If water is generated inside the auxiliary case 310, the water is drained to the outside of the auxiliary case 310 through the opening 310a. As described above, the water discharged to the outside of the auxiliary case 310 flows through the protruding surface 330 and / or the first drainage channel 340 and / or the second drainage channel 350 of the pack case 300, and then is discharged to the outside of the battery pack through the drain port 360.

[0121] 8 and 9, the shape of the bottom of the auxiliary case 310 may be flat. However, the present invention is not limited to the illustrated examples and various modifications and variations are possible. For example, the bottom of the auxiliary case 310 may include components having the same shape and structure as the protruding surface 330 and / or the first drainage channel 340 and / or the second drainage channel 350, like the bottom of the pack case 300.

[0122] Hereinafter, a description will be given of an embodiment of the present invention in which the drain outlet is sealed during a thermal event to improve fire extinguishing performance of the battery pack.

[0123] According to one embodiment of the present invention, the pack case 300 includes a thermal expansion member 360a provided in the drain port 360. Figures 14 and 15 each show an embodiment of the thermal expansion member 360a. Figure 14 shows a case in which the thermal expansion member 360a is disposed in contact with the entire or partial inner surface of the drain port 360. Figure 15 shows a case in which the thermal expansion member 360a is disposed a predetermined distance away from the inner surface of the drain port 360.

[0124] 14 shows a case where the thermal expansion member 360a is disposed in contact with the entire or a portion of the inner surface of the drain outlet 360. The thermal expansion member 360a may surround the entire inner surface of the drain outlet 360. Alternatively, the thermal expansion member 360a may be disposed on only a portion of the inner surface of the drain outlet 360. In the latter case, for example, the thermal expansion member 360a may be disposed only partially along the length of the drain outlet 360, and the thermal expansion member 360a may be disposed entirely around the vertical cross section of the drain outlet 360. In other words, it is sufficient that the thermal expansion member 360a can effectively seal the drain outlet 360 in the event of a fire or thermal runaway of the cell module assembly 100, as described below.

[0125] Figure 15 shows a case where the thermal expansion member 360a is arranged at a predetermined distance from the inner surface of the drain port 360. In this case, a thermal expansion member joining portion 360b is further provided across the cross section of the drain port 360. Figure 15 shows a cross section of the drain port 360 and the thermal expansion member joining portion 360b across it, viewed from the inlet side of the drain port 360.

[0126] For example, a groove may be formed on at least one end of the thermal expansion member 360a, and the thermal expansion member coupling portion 360b may be bar-shaped. The thermal expansion member 360a may be disposed a predetermined distance away from the inner surface of the drain hole 360, with the thermal expansion member coupling portion 360b fixedly coupled to the groove of the thermal expansion member 360a. When viewing the cross section of the drain hole 360, for example, the inner surface of the drain hole 360 ​​and the thermal expansion member 360a may be disposed coaxially.

[0127] Meanwhile, the thermal expansion member 360a may have, for example, a pin shape arranged along the path of the drain hole 360. Although Fig. 15 shows an example in which the thermal expansion member 360a has a pin shape, the present invention is not limited thereto, and it is sufficient if the thermal expansion member 360a has a structure or shape that can effectively seal the drain hole 360 ​​in the event of a fire or thermal runaway in the cell module assembly 100.

[0128] 15 shows a case where the thermal expansion member joining portion 360b is provided at the entrance of the drain outlet 360 (inside the pack case 300), but the present invention is not limited to this and the thermal expansion member joining portion 360b may be provided in the path of the drain outlet 360, or at the exit of the drain outlet 360 (outside the pack case 300). In other words, the shape, position, and structure of the thermal expansion member joining portion 360b are sufficient as long as the thermal expansion member joining portion 360b does not block the drain outlet 360 and the thermal expansion member 360a can be positioned at the drain outlet 360.

[0129] The thermal expansion member 360a is configured to expand in volume above a predetermined temperature to seal the drain port 360. In the event of a fire or thermal runaway in the cell module assembly 100, the thermal expansion member 360a expands in volume due to high-temperature gas, and the expanded thermal expansion member 360a can seal the drain port 360. When a fire extinguishing agent (fire extinguishing liquid) is supplied into the pack case 300 from a fire extinguishing unit (e.g., a fire tank 400 located above the cell module assembly 100), the thermal expansion member 360a sealing the drain port 360 prevents the fire extinguishing agent (fire extinguishing liquid) from being discharged to the outside of the pack case 300 through the drain port 360. This allows the fire extinguishing agent (fire extinguishing liquid) to remain in the cell module assembly 100 inside the pack case 300 for a long time. This means that fires and thermal runaway in the cell module assembly 100 can be more stably extinguished.

[0130] Meanwhile, the present invention is not limited to the fire extinguishing tank 400 described above, but can be applied to any fire extinguishing unit that can supply a fire extinguishing agent (fire extinguishing liquid) into the pack case 300. For example, the fire extinguishing unit may be located outside the pack case 300, and the fire extinguishing agent (fire extinguishing liquid) may be supplied into the pack case 300 through a pipe connected to the fire extinguishing unit. Alternatively, for example, a cooling plate structure may be located on the top or bottom of the pack case 300, and the fire extinguishing agent (fire extinguishing liquid) may be supplied into the pack case 300 when a thermal event occurs. The present invention is not limited to the fire extinguishing unit described above, and various modifications and variations may be made to suit the environment in which the present invention is embodied.

[0131] For this purpose, the thermal expansion member 360a may be made of various thermal expansion materials known at the time of filing of the present invention. For example, the thermal expansion member 360a may be made of a polymer material with a large thermal expansion coefficient. The thermal expansion member 360a may be made of a polymer material such as PDMS (Poly-Di-Methyl-Siloxane), polyvinyl acetate, polystyrene, butyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, or a combination thereof, and may be thermally expandable.

[0132] The thermal expansion member 360a may further include a heat-resistant material. For example, the outer surface of the thermal expansion member 360a may be coated with a heat-resistant material such as ceramic. Alternatively, the thermal expansion member 360a may include a core of a heat-resistant material such as ceramic provided along the length of the thermal expansion member 360a. For example, the thermal expansion member 360a may surround a core of a heat-resistant material. This allows the thermal expansion member 360a to expand in volume due to the heat of the venting gas but not be damaged.

[0133] The thermal expansion of the thermal expansion member 360a can be suitably set depending on the shape and thermal expansion coefficient of the thermal expansion material contained in the thermal expansion member 360a. The degree of thermal expansion of the thermal expansion member 360a can be suitably set by the user depending on various conditions, such as the size or shape of the thermal expansion member 360a and the drain hole 360, and the type of battery cell.

[0134] Fig. 16 is a perspective view of fire tank 400 included in the battery pack of Fig. 5. Fig. 17 is a perspective cross-sectional view of fire tank 400 of Fig. 16, showing a cross section taken along line A5-A5' of Fig. 5.

[0135] 1, the fire extinguishing tank 400 includes a lower tank 410 and an upper cover 420. The lower tank 410 and the upper cover 420 may be manufactured separately and then hermetically coupled, or may be manufactured as an integrated unit. The upper cover 420 may further include an inlet 430 through which a fire extinguishing agent can be injected. The inlet 430 may be closed with a cap to seal the fire extinguishing tank 400.

[0136] The thinner portion of the base plate 411 of the lower tank 410 may function as the weak portion 411a. In other words, if a thermal event occurs in the battery cell 110 of the cell module assembly 100, the weak portion 411a, which is relatively thinner, may be damaged first. If the weak portion 411a is damaged and an opening is formed in the base plate 411, the extinguishing agent held inside the fire tank 400 may be discharged to the cell module assembly 100 side through the weak portion 411a.

[0137] A plurality of fragile portions 411a may be provided. The fragile portions 411a may have, for example, a narrow width and a long length. That is, they may have a linear shape and be arranged parallel to one edge of the fire extinguisher tank 400, and the fragile portions 411a may be arranged parallel to each other.

[0138] According to this embodiment, the length direction of the battery cell 110 (for example, the Y-axis direction in the drawing) and the length direction of the vulnerable portions 411a (for example, the X-axis direction in the drawing) can be perpendicular to each other. In other words, a plurality of vulnerable portions 411a are arranged intersecting the length direction of the battery cell 110. This allows the extinguishing agent to be supplied simultaneously through the plurality of open vulnerable portions 411a throughout the entire battery cell 110 along the length direction of the battery cell 110 in which a thermal event has occurred, thereby more efficiently and quickly extinguishing the fire in the battery cell 110 in which a thermal event has occurred.

[0139] The lower surface of the base plate 411 of the fire tank 400 and the upper surface of the cell module assembly 100 have shapes that are approximately the same. As a result, the fire tank 400 is disposed in closer contact with the cell module assembly 100, which allows the battery cells 110 that have experienced temperature increases to be cooled more effectively and allows fire extinguishing agent to be injected more quickly into the battery cells 110 that have experienced overheating or ignition. In addition, more fire extinguishing agent can be efficiently stored in the fire tank 400. In other words, if the height of the base plate 411 of the lower tank 410 of the fire tank 400 is uniform overall, the fire tank 400 will store less fire extinguishing agent due to the empty space.

[0140] The extinguishing agent provided in the fire extinguishing tank 400 may be in the form of, for example, a fire extinguishing liquid, and a duplicated description will be omitted and reference will be made to the above.

[0141] FIG. 18 is a perspective view of a battery pack in which all of the components of the battery packs described above with reference to FIGS. 5 to 17 are combined.

[0142] In addition, where the description of the battery packs of FIGS. 5 to 18 overlaps with the description of the battery packs of FIGS. 1 to 4, reference should be made to what has been described above with reference to FIGS.

[0143] Meanwhile, a plurality of pack cases 300 may be provided and configured to be stackable in the vertical direction, which will be described in more detail with reference to Figures 19 to 21.

[0144] Figure 19 is a perspective view schematically illustrating the configuration of at least a portion of the battery pack of Figures 1 to 18 of the present invention. Figures 20 and 21 are drawings showing an embodiment in which a plurality of pack cases 300 shown in Figure 19 are stacked. For ease of understanding, Figures 19 to 21 illustrate the battery packs schematically, and the detailed configuration of the battery packs is described above with reference to Figures 1 to 18.

[0145] 19, the pack case 300 may have a bottom and sidewalls. The cell module assembly 100 may be housed in the internal space of the pack case 300, and the top of the cell module assembly 100 is covered with a fire tank 400 to form a battery pack. For reference, in FIG. 19, the height of the upper side of the pack case 300 is shown to be higher than the height of the upper surface of the fire tank 400. However, FIG. 19 is a schematic view and merely an embodiment, and the present invention is not limited to what is shown in FIG. 19. In other words, various modifications are possible, such as the opposite, the height of the upper surface of the fire tank 400 may be higher than the height of the upper side of the pack case 300, or the height of the upper surface of the fire tank 400 may be the same as the height of the upper side of the pack case 300.

[0146] A plurality of pack cases 300 as shown in Fig. 19 may be provided to form a stacked structure of battery packs as shown in Fig. 20 or 21. In this case, the battery pack of Fig. 19 may be one unit pack. A plurality of such unit packs may be provided to form a modular stacked overall battery pack as shown in Fig. 20 or 21.

[0147] More specifically, for example, the configuration of Fig. 20 shows a configuration in which three unit packs D are stacked vertically, and the configuration of Fig. 21 shows a configuration in which five unit packs D are stacked vertically. The present invention is not limited to the illustrated configuration, and the number of unit packs D can be variously changed to suit the environment in which the present invention is embodied.

[0148] For example, when the battery pack of the present invention is embodied as an energy storage system (ESS), various voltages and / or storage capacities of the energy storage system can be realized by adjusting the number of unit battery packs. According to this embodiment of the present invention, a single unit pack having a common structure can be stacked in various ways, and products with various voltages and / or storage capacities can be realized depending on the number of stacks. For example, by adjusting the number of stacks of the same unit pack, it is possible to realize a low-voltage product as shown in FIG. 20 and a high-voltage product as shown in FIG. 21. Therefore, compared to products limited to a specific voltage standard, economic efficiency and compatibility can be improved. Furthermore, this embodiment also allows products with various capacities to be realized depending on the number of stacks.

[0149] In other words, when stacked unit packs are connected in series, products with various voltages can be realized depending on the number of stacked packs. Also, when stacked unit packs are connected in parallel, products with various capacities (storage capacities) can be realized depending on the number of stacked packs.

[0150] In particular, each unit pack D may include a cell module assembly 100 therein. Also, as described above, each unit pack D includes a connector 610 so that the cell module assemblies 100 can be electrically connected to each other when stacked. In particular, such connector 610 may be configured to couple the unit packs D to each other by stacking them one above the other.

[0151] In addition, in the above embodiment, each unit pack D may house a fire tank 400 together with the cell module assembly 100. That is, each unit pack D includes the fire tank 400 on top of the cell module assembly 100, as described above. A battery pack formed by stacking multiple battery packs has a stacked structure of fire tank 400-cell module assembly 100-fire tank 400-cell module assembly 100 from top to bottom. The stacked battery pack of the present invention having this structure can be configured by increasing (expanding) the number of cell module assemblies 100 to increase various voltages and / or storage capacities, while also safely preparing for thermal events such as fires in the cell module assemblies 100. Therefore, this embodiment of the present invention can further improve the safety of the battery pack.

[0152] Referring again to FIG. 19, another example of a coupling method between vertically stacked battery packs (pack cases) 300 is as follows. The upper end of the side wall of the pack case 300 may have a step, such as a coupling step C1, that is recessed inward. For example, this step may be a portion where the thickness of the side wall of the pack case 300 is thin. Also, although not shown in FIG. 19, the bottom of the pack case 300 may have a coupling recess into which the coupling step C1 of the side wall is inserted. That is, when different pack cases 300 are stacked vertically, the coupling step C1 formed on the upper end of the side wall of the lower pack case 300 may be inserted into the coupling recess formed on the bottom of the upper pack case 300. As a result, when multiple pack cases 300 are stacked vertically and coupled, the outer surfaces of the pack cases 300 may have an overall flat shape.

[0153] Meanwhile, the coupling method for the fastening structure between the vertically stacked battery packs is not limited to that shown in FIG. 19 and / or FIG. 8, and various other coupling methods can be modified or changed and applied to the present invention.

[0154] The battery pack of the present invention may also be connected to a battery management system (BMS, not shown). The battery management system monitors and manages the battery pack(s). The battery management system may be located on the top layer of a stack of battery packs. However, the location of the battery management system is not limited to the above and may be variously modified or changed to suit the manner or environment in which the present invention is embodied.

[0155] In addition to the above-described components, the battery pack according to the present invention may further include various other components included in the battery pack. For example, the battery pack according to the present invention may include many electrical components for controlling or managing the charging and discharging of the battery pack, such as a battery management system (BMS), relays, fuses, and current sensors.

[0156] An energy storage system (ESS) according to the present invention includes one or more battery packs according to the present invention. In addition to the battery pack, the energy storage system according to the present invention may further include other general components included in an energy storage system.

[0157] Meanwhile, although terms indicating directions such as up, down, left, and right may be used in this specification, it will be obvious to those skilled in the art that such terms are used merely for convenience of explanation and may vary depending on the position of the object of interest, the position of the observer, etc.

[0158] As described above, the present invention has been described using limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary skill in the art to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims set forth below. [Explanation of symbols]

[0159] 100: Cell module assembly 110: Battery cell 120: End plate 130: Busbar housing 140: Strap 200: Blocking member 210: Support plate 220:Swelling pad 230:Through hole 300: Pack case 300a: Lower case 300b: Upper case 310: Auxiliary case 310a: opening 320: Venting port 330:Protruding surface 340: 1st drainage canal 350:Second drainage canal 360: Drain 360a: Thermal expansion member 360b: Thermal expansion member joint 370: Connector through hole 380: Compartment wall 400: Fire tank 410: Lower tank 411: Base plate 411a: Weak area 412: Side wall 420: Upper cover 430: Inlet 500:External cover 600: Electrical connection unit 610: Connector

Claims

1. a cell module assembly including a battery cell stack in which a plurality of battery cells are stacked; a pack case that houses the cell module assembly in its internal space; and a fire extinguishing unit that supplies a fire extinguishing agent into the pack case when a thermal event occurs in the battery cell to extinguish the fire in the battery cell; The battery pack, wherein the pack case includes at least one drain hole in at least one of a lengthwise edge and a widthwise edge of the bottom surface of the pack case.

2. The battery pack according to claim 1 , further comprising a thermal expansion member located at the drain port, the thermal expansion member expanding in volume at a predetermined temperature or higher to seal the drain port.

3. The thermal expansion member is disposed at a predetermined distance from an inner surface of the drain outlet, The battery pack according to claim 2 , further comprising a thermal expansion member coupling portion disposed across a cross section of the drain hole to secure the thermal expansion member.

4. a groove on at least one end of the thermal expansion member; The thermal expansion member joint is bar-shaped, The battery pack according to claim 3 , wherein the thermal expansion member joining portion is fixedly joined to the groove of the thermal expansion member.

5. The battery pack according to claim 3 , wherein the thermal expansion member joint is disposed at at least one of an inlet and an outlet of the drain port.

6. The battery pack according to claim 2 , wherein the thermal expansion member has a pin shape that is arranged along the path of the drain hole.

7. The battery pack according to claim 2 , wherein the thermal expansion member and the inner surface of the drain hole are arranged coaxially.

8. The battery pack according to claim 2 , wherein the thermal expansion member contacts and surrounds at least a portion of an inner surface of the drain port.

9. The battery pack according to claim 2 , wherein the thermal expansion member is made of a polymer material.

10. 10. The battery pack of claim 9, wherein the thermal expansion member is any one selected from the group consisting of PDMS (polydimethylsiloxane), polyvinyl acetate, polystyrene, butyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, and combinations thereof.

11. 3. The battery pack of claim 2, wherein the thermal expansion member includes a core of heat-resistant material positioned within the thermal expansion member along the length of the thermal expansion member.

12. The battery pack according to claim 1 , wherein the fire extinguishing unit is a fire extinguishing tank located above the cell module assembly and covering an upper surface of the pack case.

13. The battery pack according to claim 1 , wherein the fire extinguishing agent is a liquid fire extinguishing agent.

14. The battery pack according to claim 1 , wherein the height of the bottom surface of the drain hole gradually decreases from the inside to the outside of the pack case.

15. The battery pack according to claim 1 , wherein the cross section of the drain hole has a tapered shape that increases in size from the inside to the outside of the pack case.

16. The pack case further includes, in its internal space, a plurality of protruding surfaces protruding upward from a bottom surface thereof, and a first drainage channel between the plurality of protruding surfaces, The battery pack according to claim 1 , wherein the plurality of protruding surfaces are arranged in a line along at least one of the length direction and the width direction of the pack case.

17. The protruding surface comprises: a top surface located at the center of the protruding surface and on which the cell module assembly is placed; and a slope formed radially from the top surface, The battery pack according to claim 16 , wherein the inclined surface decreases in height from the top surface to an edge of the protruding surface.

18. The top surface has a circular plate shape, The battery pack according to claim 17 , wherein the radially inclined surfaces are disposed equiangularly with respect to the center of the protruding surface.

19. The battery pack according to claim 16 , wherein the first drainage channels are arranged parallel to at least one of the lengthwise edge and the widthwise edge of the bottom surface of the pack case.

20. The battery pack according to claim 16 , wherein a bottom surface of the drain hole has the same height as or lower than the first drain channel.

21. the internal space of the pack case further includes second drainage channels disposed on the lengthwise edges and widthwise edges of the bottom surface of the pack case; The battery pack according to claim 16 , wherein the second drainage channel has a height equal to or lower than that of the first drainage channel.

22. The battery pack according to claim 21 , wherein a bottom surface of the drain hole has the same height as or lower than the second drain channel.

23. the pack case further includes a plate-shaped partition wall disposed across the pack case, the internal space of the pack case is divided into a storage space for the cell module assembly and a storage space for the electrical connection unit based on the partition wall; The battery pack according to claim 16 , wherein the plurality of protruding surfaces and the first drainage channel are provided in at least one of the storage space of the cell module assembly and the storage space of the electrical connection unit.

24. further comprising an auxiliary case made of a metal material for temporarily housing the cell module assembly; the cell module assembly is housed in the auxiliary case, and the auxiliary case is placed on the uppermost surface of the protruding surface of the pack case; The battery pack of claim 16 , wherein the auxiliary case includes at least one opening on a bottom surface of the auxiliary case.

25. The battery pack according to claim 24 , wherein the opening is provided at an edge of the bottom surface of the auxiliary case or at a corner of the bottom surface of the auxiliary case.

26. The battery pack is provided in a plurality of pieces, 2. The battery pack according to claim 1, wherein the plurality of battery packs are connected to each other by mechanical or electrical connections.

27. 27. The battery pack according to claim 26, wherein the plurality of battery packs can be stacked vertically.

28. 27. The battery pack of claim 26, wherein the plurality of battery packs are electrically connected in series so that various voltages of the plurality of battery packs can be realized.

29. The battery pack of claim 26, wherein the plurality of battery packs are electrically connected in parallel so that the storage capacities of the plurality of battery packs can be variably realized.

30. 30. An energy storage device comprising a battery pack according to any one of claims 1 to 29.

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