Battery rack and power storage device including same

Abstract

A battery rack according to one embodiment of the present invention includes at least one battery pack and a rack frame on which the battery pack is mounted, the battery pack including a battery cell stack in which a plurality of battery cells are stacked, a pack frame that houses the battery cell stack, and a cooling member located on the upper side of the battery cell stack and containing cooling water, the cooling member being connected to a water tank mounted on the rack frame, and a lower plate of the cooling member being formed with at least one weak part that breaks or melts at a predetermined temperature or above or a predetermined pressure or above, and when the weak part of the cooling member is opened and the level of the cooling water drops, cooling water is supplied from the water tank to the cooling member.

Description

[Technical field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0015920 dated February 8, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery rack and a power storage device including the same, and more particularly to a battery rack for preventing a chain reaction of thermal runaway phenomena and a power storage device including the same. [Background technology]

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

[0004] Currently, commercial secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Of these, lithium secondary batteries are attracting the most attention due to their advantages of being freely chargeable and dischargeable, having a low self-discharge rate, and having a high energy density.

[0005] Meanwhile, in the case of a secondary battery used in a small device, two or three battery cells are mainly used, whereas in the case of a secondary battery used in a medium-sized or large device such as an automobile, a medium-sized or large battery module or battery pack in which a plurality of battery cells are electrically connected is used. Here, a battery pack is generally constructed by first constructing a battery module including at least one battery cell, and then adding other components to the at least one battery module, but this is not necessarily the case, and the battery cell can be directly attached to the battery pack. Also, the battery pack may be configured as a power storage device equipped with a battery rack including at least one such battery pack according to various voltage and capacity requirements. Meanwhile, since it is preferable that the battery module or battery pack is manufactured to be small in size and weight, prismatic batteries, pouch-type batteries, etc., which can be stacked with a high degree of integration and are light in weight relative to their capacity, are mainly used.

[0006] Meanwhile, the battery cells installed in the battery pack may generate a large amount of heat during charging and discharging, and if the temperature rises above the appropriate temperature due to overcharging or other reasons, the performance may deteriorate, and if the temperature rises excessively, there is a risk of explosion or fire. If a fire occurs in at least one of the battery packs included in the battery rack, the flames and heat may spread to the surrounding battery packs, leading to additional fires and causing serious property losses and serious injury to human life.

[0007] Recently, in order to prevent such thermal runaway, a method has been developed to extinguish a fire by injecting cooling water into the battery pack when a fire occurs. However, since a relatively large amount of cooling water is required to extinguish a thermal runaway, there is a problem that the fire extinguishing effect is somewhat reduced if the injected cooling water is insufficient.

[0008] Therefore, there is a need to find a solution to provide a battery rack and a power storage device including the same that can prevent the spread of flames and heat to adjacent battery packs by supplying a sufficient amount of cooling water when at least one of the battery packs catches fire. Summary of the Invention [Problem to be solved by the invention]

[0009] The problem to be solved by the present invention is to provide a battery rack and a power storage device including the same that can inject a sufficient amount of cooling water at an appropriate time and place when at least one of the battery packs catches fire internally.

[0010] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0011] A battery rack according to one embodiment of the present invention includes at least one battery pack and a rack frame on which the battery pack is mounted, the battery pack including a battery cell stack in which a plurality of battery cells are stacked, a pack frame that houses the battery cell stack, and a cooling member located on the upper side of the battery cell stack and containing cooling water, the cooling member being connected to a water tank mounted on the rack frame, and a lower plate of the cooling member being formed with at least one weak part that breaks or melts at a predetermined temperature or above or a predetermined pressure or above, and when the weak part of the cooling member is opened and the level of the cooling water drops, cooling water is supplied from the water tank to the cooling member.

[0012] The water tank may be disposed on an upper portion of the rack frame.

[0013] The cooling member includes an inlet port and an outlet port for injecting cooling water into an internal space, and the inlet port and the outlet port are connected to an external cooling system so that the cooling water of the cooling member can circulate through the inlet port and the outlet port.

[0014] The inlet port may be connected to the cooling system through an inlet manifold, the outlet port may be connected to the cooling system through an exhaust manifold, and the water tank may be connected to the exhaust manifold.

[0015] The battery pack may be a plurality of battery packs, and the water tank may be connected to each of the cooling members included in the plurality of battery packs.

[0016] A number of openings may be formed in a lower plate of the cooling member, the openings being closed by a sealing member, and the weak portion may be a portion of the lower plate where the openings closed by the sealing member are located.

[0017] The cooling member may include a cooling tube providing a flow path for cooling water and a cooling hose attached to the cooling tube, a number of openings may be formed in the lower plate, the cooling hoses may be positioned to correspond to the openings, and the weak portion may be a portion of the lower plate where the openings closed by the cooling hoses are located.

[0018] The lower plate and the cooling tubes can be connected by a strap-shaped fastening member.

[0019] The lower plate may include a first portion in which the weak portion is formed and a second portion in which the weak portion is not formed, and a thickness value of the first portion may be smaller than a thickness value of the second portion.

[0020] The first portion may have a thickness value less than or equal to half the thickness value of the second portion.

[0021] The lower plate may be formed by joining a first layer and a second layer having different thicknesses, the thickness of the first portion corresponding to the thickness of the first layer and the thickness of the second portion corresponding to the thicknesses of the first layer and the second layer.

[0022] An upper plate coupled to the lower plate of the cooling member may include a bent portion, a peak of the bent portion corresponding to the first portion, and a valley of the bent portion corresponding to the second portion.

[0023] The top plate of the cooling member may be integral with the pack frame.

[0024] A power storage device according to another embodiment of the present invention includes at least one battery rack as described above. Effect of the Invention

[0025] According to one embodiment, cooling water can be injected from a cooling member inside the battery pack into a battery cell where thermal runaway has occurred, and at this time, a sufficient amount of cooling water can be supplied from the water tank to the cooling member, thereby quickly extinguishing the internal fire and preventing further thermal runaway.

[0026] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief description of the drawings]

[0027] [Figure 1] 1 is a perspective view of a power storage device including a battery rack according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a schematic diagram of one side of the battery rack shown in FIG. 1. [Diagram 3] 1A and 1B are diagrams for explaining changes in the battery rack before and after a thermal runaway phenomenon. [Figure 4] 1A and 1B are diagrams for explaining changes in the battery rack before and after a thermal runaway phenomenon. [Diagram 5]FIG. 2 is a perspective view of a battery pack included in a battery rack according to an embodiment of the present invention. [Figure 6] FIG. 6 is an exploded perspective view of a battery pack included in the battery rack according to FIG. 5. [Figure 7] FIG. 6 is an exploded perspective view of a battery pack included in the battery rack according to FIG. 5. [Figure 8] FIG. 6 is a perspective view of a cell block included in the battery pack according to FIG. 5. [Figure 9] 6 is a diagram showing a lower plate of a cooling member included in the battery pack according to FIG. 5. FIG. [Figure 10] 10A and 10B are diagrams for explaining changes in a cooling member before and after a thermal runaway phenomenon. [Figure 11] 10A and 10B are diagrams for explaining changes in a cooling member before and after a thermal runaway phenomenon. [Figure 12] 6 is a diagram illustrating a change that occurs after a thermal runaway phenomenon occurs when a foam pad is provided in the battery pack shown in FIG. 5. FIG. [Figure 13] FIG. 11 is a perspective view showing a cooling member of a battery pack included in a battery rack according to another embodiment of the present invention. [Figure 14] 14 is a diagram showing the connection between a lower plate and a cover film included in the cooling member shown in FIG. 13. [Figure 15] 13 is a perspective view showing a lower plate of a cooling member for a battery pack included in a battery rack according to another embodiment of the present invention. FIG. [Figure 16] FIG. 16 is a diagram showing an example of the AA cross section of FIG. 15. [Figure 17] 16 is a cross-sectional view of a lower plate for explaining a modified example of the cooling member shown in FIG. [Figure 18] 16 is a cross-sectional view of a lower plate for explaining another modified example of the cooling member shown in FIG. [Figure 19] 16 is a cross-sectional view of a cooling member for illustrating still another modified example of the cooling member in FIG. [Figure 20] FIG. 11 is a perspective view showing a cooling member of a battery pack included in a battery rack according to another embodiment of the present invention. [Figure 21] FIG. 21 is a top view of the cooling member according to FIG. 20. [Figure 22] 21 is a diagram showing the connection between a lower plate, a cooling tube, and a cooling hose included in the cooling member shown in FIG. 20. FIG. [Diagram 23] 22 shows the cooling member of FIG. 21 cut along line BB, and illustrates the flow of cooling water into and out of the cooling tubes and cooling hoses. FIG. [Figure 24] 22 is a cross-sectional view of the cooling member shown in FIG. 21 taken along line BB, showing the injection of cooling water through a cooling hose when a battery cell catches fire. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: FIG. 1 is a block diagram of a semiconductor device according to an embodiment of the present invention;

[0029] In order to clearly explain the present invention, parts that are not necessary for the explanation will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0030] In addition, the size and thickness of each component shown in the drawings are arbitrarily enlarged or reduced for the convenience of explanation, and it is obvious that the contents of the present invention are not limited to those shown in the drawings. In the following drawings, the thickness of each layer is enlarged to clearly show various layers and regions. In the following drawings, the thickness of some layers and regions is exaggerated for the convenience of explanation.

[0031] In addition, when a layer, film, region, plate, etc. is described as being "on" or "above" another part, this should be interpreted as including not only the case where the layer, film, region, plate, etc. is "directly on" the other part, but also the case where there is another part therebetween. Conversely, when a layer, film, region, plate, etc. is described as being "directly on" the other part, it can mean that there is no other part therebetween. In addition, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" the opposite direction to gravity. Meanwhile, similar to the description of being "on" or "above" another part, the description of being "below" or "below" another part should be understood with reference to the above content.

[0032] In addition, since the top / bottom of a particular component can be determined differently depending on the reference direction, throughout this specification, 'top' or 'bottom' is defined to mean two opposing surfaces of the component along the z-axis.

[0033] Additionally, throughout the specification, when a part is said to "comprise" a certain element, this means that it may further include other elements, but not excluding other elements, unless specifically stated to the contrary.

[0034] Additionally, throughout the specification, the term "on a plane" means the part in question viewed from above, and the term "in cross section" means the part in question viewed from the side on a vertical cross section.

[0035] Hereinafter, a battery rack and a power storage device including the battery rack according to an embodiment of the present invention will be described.

[0036] Fig. 1 is a perspective view of a power storage device including a battery rack according to an embodiment of the present invention. Fig. 2 is a schematic view of one side of the battery rack according to Fig. 1. Figs. 3 and 4 are views for explaining changes in the battery rack before and after a thermal runaway phenomenon. Here, Fig. 2 shows the battery rack of this embodiment without showing the inflow / outflow manifolds and the cooling system in order to explain the connection between the in / out ports of the cooling member and the inflow / outflow manifolds.

[0037] 1, the power storage device 1 of this embodiment may include at least one battery rack 10, which will be described below. The power storage device 1 is an energy source and may be used for home or industrial purposes.

[0038] 1 to 4, a battery rack 10 according to the present embodiment may include at least one battery pack 1000 mounted on a rack frame 11. The battery pack 1000 of the battery rack 10 may be connected to a water tank 2000. The battery rack 10 may include the battery pack 1000 and the water tank 2000.

[0039] The battery pack 1000 of the present embodiment may include a cooling member 500. The cooling member 500 may be provided to lower the internal temperature of the battery module or the battery pack, including the battery cells. The cooling member 500 may be a water-cooled cooling member 500 into which a refrigerant or coolant is injected. Since the cooling member 500 is provided in a water-cooled manner, the cooling efficiency of the cooling member 500 can be uniformly maintained, and the battery cells in the battery module or the battery pack can be uniformly cooled. In this case, the cooling water used in the cooling member 500 may be one of known types or a mixture thereof, and any known type may be used as long as it can move along a flow path inside the cooling member 500 to release heat from the battery cells.

[0040] The cooling water in the cooling member 500 can be designed to circulate continuously in order to maintain its temperature constant by connecting it to an external cooling system 60 through an inlet / outlet port 530. The inlet port 532 of the cooling member 500 can be connected to the inlet manifold 40, and the outlet port 534 can be connected to the exhaust manifold 20.

[0041] The exhaust manifold 20 and the inlet manifold 40 may be connected to a cooling system 60. The cooling system 60 may be connected in parallel to each cooling member 500 included in the battery rack 10. The cooling system 60 may include a pump that can facilitate the supply of cooling water to the cooling member 500. When the cooling system 60 includes a pump, a low pressure portion of the pump, i.e., the inlet of the pump, may be connected to the exhaust manifold 20, and a high pressure portion of the pump, i.e., the exhaust port of the pump, may be connected to the inlet manifold 40.

[0042] Meanwhile, in order to effectively suppress a fire in a battery cell, it may be effective to inject a liquid such as cooling water into the battery module or battery pack. Since providing a liquid tank inside the battery module or battery pack may cause a problem of increasing the volume of the battery module and the battery pack, a separate water tank has been provided outside the battery module and the battery pack in the past, and cooling water or the like has been injected into the battery module or battery pack through a nozzle extended from the water tank only when a battery cell fire is confirmed by a sensor.

[0043] However, the conventional water injection system must have a separate control unit or communication unit to determine whether or not to inject cooling water, and errors must not occur in these operations, and even if they operate normally, they must go through many judgment processes, which takes a lot of time. Even after it is decided to inject cooling water, if the path from the water tank to the battery module or battery cell inside the battery pack is somewhat long, it is difficult to quickly supply cooling water from the water tank to the battery cell, and it is difficult for the conventional water injection system to stop the rapid and continuous thermal runaway phenomenon. Therefore, in the present embodiment, a fragile part 600 (see FIG. 10, etc.) that melts or breaks at a predetermined temperature or pressure can be formed in the cooling member 500 so that cooling water can be immediately supplied to the fire site when an internal fire occurs in the battery pack 1000.

[0044] However, if a fire occurs in a particular battery cell, a large amount of cooling water is required to suppress the fire, but since the cooling member 500 of the present embodiment is located inside the battery pack 1000, there may be a limit to how much its volume can be increased. Therefore, even if cooling water is injected into the battery pack 1000 by opening the fragile portion 600, the amount of cooling water may be insufficient and the fire may not be suppressed effectively. Therefore, the battery rack 10 of the present embodiment may include a water tank 2000 that can supply additional cooling water to the cooling member 500.

[0045] The water tank 2000 may be connected to the discharge manifold 20. The water tank 2000 may be connected to the discharge manifold 20 through which low pressure cooling water flows. In a situation where additional cooling water is required, the cooling water in the water tank 2000 may be input to the cooling member 500 through the discharge manifold 20. The discharge manifold 20 may include a pipe branched off from a pipe connected to the outlet port 534 of the cooling member 500 to be connected to the water tank 2000.

[0046] 3, before a fire occurs, the cooling water may circulate in the direction of the arrow through the inlet manifold 40, the inlet port 532, the outlet port 534, the discharge manifold 20, and the cooling system 60 in that order. At this time, the cooling water circulates along a closed circuit and the level of the cooling water in the cooling member 500 is maintained constant, so that the cooling water in the water tank 2000 may not be supplied to the inside of the cooling member 500. The cooling water in the water tank 2000 may not be circulated by the cooling system 60.

[0047] 4, after an ignition event occurs, the cooling water in the cooling member 500 is injected into the battery pack 1000, and the water level in the cooling member 500 may decrease. At this time, the cooling water in the water tank 2000 is supplied to the cooling member 500 by gravity or hydraulic pressure difference, so that additional cooling water is injected into the battery pack 1000, and the ignition event in the battery pack 1000 can be effectively suppressed.

[0048] At this time, the circulation of the cooling water by the cooling system 60 can be stopped. The cooling system 60 can be programmed to stop operating if an ignition occurs in the battery pack 1000. However, this is not necessarily the case, and the cooling system 60 may be designed to continue operating even after the battery pack 1000 ignites.

[0049] The water tank 2000 may be fixed to the rack frame 11. Specifically, the water tank 2000 may be disposed in an empty space in the rack frame 11, for example, on the upper part of the rack frame 11. As shown in Fig. 1, if the water tank 2000 is located in the empty space on the upper part of the rack frame 11, an additional water tank 2000 can be provided in the battery rack 10 without increasing the volume of the battery rack 10 itself, thereby improving the space efficiency of the battery rack 10.

[0050] In addition, if the water tank 2000 is located at the top of the rack frame 11, the cooling water may be easily injected from the water tank 2000 to the cooling member 500 by gravity. If the water tank 2000 is located below the cooling member 500, the water tank 2000 may need to be equipped with a pump or the like to supply additional cooling water to the cooling member 500, but if the water tank 2000 is located above the cooling member 500, the cooling water can be supplied by gravity, which is advantageous in terms of simplifying the structure or design.

[0051] Hereinafter, a battery pack included in a battery rack according to an embodiment of the present invention will be described in more detail.

[0052] Typically, a conventional battery pack has a double assembly structure in which a battery module is formed by assembling a battery cell stack and various components connected thereto, and a plurality of battery modules are then housed in a battery pack.

[0053] At this time, since the battery module includes a module frame that forms its outer surface, the conventional battery cells are doubly protected by the module frame of the battery module and the pack frame of the battery pack. However, such a double assembly structure not only increases the manufacturing cost and manufacturing process of the battery pack, but also has the disadvantage of poor reassembly when a defect occurs in some battery cells. In addition, when a cooling member is present outside the battery module, the heat transfer path between the battery cells and the cooling member becomes somewhat complicated.

[0054] Therefore, the battery cell stack of this embodiment can be provided in a structure that is not sealed by a module frame, and can be directly coupled to the pack frame of the battery pack. This simplifies the structure of the battery pack, provides advantages in terms of manufacturing cost and manufacturing process, and has the effect of achieving a lightweight battery pack. In addition, this allows the battery cell stack to be disposed closer to the cooling member in the pack frame, making it easier to dissipate heat through the cooling member.

[0055] Therefore, the "battery pack" described below is a structure including a battery cell stack and a frame that houses the battery cell stack, and is not limited to including a conventional sealed battery module, but can broadly refer to a structure in which a battery cell stack and various parts connected thereto are assembled. From this perspective, the battery pack of the present embodiment can be referred to as a battery module as necessary.

[0056] Fig. 5 is a perspective view of a battery pack included in a battery rack according to an embodiment of the present invention. Figs. 6 and 7 are exploded perspective views of a battery pack included in the battery rack according to Fig. 5. Fig. 8 is a perspective view of a cell block included in the battery pack according to Fig. 5. Fig. 9 is a view showing a lower plate of a cooling member included in the battery pack according to Fig. 5. Figs. 10 and 11 are views for explaining changes in the cooling member before and after a thermal runaway phenomenon. Fig. 12 is a view for explaining changes after a thermal runaway phenomenon when a foam pad is provided in the battery pack according to Fig. 5.

[0057] 5 to 8, a battery pack 1000 according to an embodiment of the present invention may include at least one cell block 100, a pack frame 200 that houses the cell block 100, a resin layer 300 formed on an inner surface of the pack frame 200, an end plate 400 that closes an open surface of the pack frame 200, and a cooling member 500 disposed between the pack frame 200 and the cell block 100. However, the components included in the battery pack 1000 are not limited thereto, and the battery pack 1000 may be provided with some of the above-mentioned components omitted or with other components not mentioned added, depending on the design.

[0058] The battery pack 1000 according to the present embodiment may include a cell block 100 that is not sealed by a frame, etc. The cell block 100 is similar to a conventional battery module in which the module frame is omitted, and therefore may be called a battery module with an 'open structure' or a 'module-less structure'.

[0059] The cell block 100 may include a battery cell stack 120 in which a plurality of battery cells 110 are stacked in one direction, side plates 130 located at both ends of the battery cell stack 120 in the stacking direction, holding straps 140 that surround the side plates 130 and the battery cell stack 120 to fix their shape, and a bus bar frame 150 that covers the front and rear of the battery cell stack 120.

[0060] Each battery cell 110 may include an electrode assembly, a cell case, and electrode leads protruding from the electrode assembly. The battery cells 110 may be provided in a pouch type or a square type that maximizes the number of cells stacked per unit area. Meanwhile, although the positive and negative leads of the battery cells 110 are shown protruding in opposite directions in Figs. 5 to 8, this is not necessarily the case, and the electrode leads of the battery cells 110 may protrude in the same direction.

[0061] The battery cell stack 120 may be formed by stacking a plurality of electrically connected battery cells 110 in one direction. The direction in which the plurality of battery cells 110 are stacked (hereinafter referred to as the 'stacking direction') may be the y-axis direction (or the -y-axis direction, and hereinafter the expression 'axis direction' may be interpreted to include both + / - directions) as shown in Figures 5 to 8.

[0062] Meanwhile, by arranging the battery cells 110 in one direction, the electrode leads of the battery cells 110 may be arranged on one side of the battery cell stack 120, or on both the one side and the other side opposite the one side. Thus, the side of the battery cell stack 120 on which the electrode leads are located may be referred to as the front or rear side of the battery cell stack 120, and the front and rear sides of the battery cell stack 120 are illustrated as two sides facing each other on the x-axis in Figures 5 to 8. Also, the side of the battery cell stack 120 on which the outermost battery cells 110 are located may be referred to as the side of the battery cell stack 120, and the side sides of the battery cell stack 120 are illustrated as two sides facing each other on the y-axis.

[0063] The side plates 130 may be provided to maintain the overall shape of the battery cell stack 120. The side plates 130 are plate-shaped members and can complement the rigidity of the cell block 100 in place of a module frame. The side plates 130 can be disposed on both ends of the battery cell stack 120 in the stacking direction, and can contact the outermost battery cells 110 on both sides of the battery cell stack 120.

[0064] The side plate 130 may be made of a variety of materials and may be provided through a variety of manufacturing methods. For example, the side plate 130 may be made of a plastic material manufactured by injection molding. For another example, the side plate 130 may be made of a leaf spring material. For still another example, the side plate 130 may be made of an elastic material such that a portion of its shape is deformed in response to a volume change of the battery cell stack 120 due to swelling.

[0065] The holding straps 140 may be for fixing the positions and shapes of the side plates 130 at both ends of the battery cell stack 120. The holding straps 140 may be members having a length and a width. Specifically, the battery cell stack 120 may be disposed between the two side plates 130 that contact the outermost battery cells 110, and the holding straps 140 may connect the two side plates 130 across the battery cell stack 120. Thus, the holding straps 140 may prevent the distance between the two side plates 130 from increasing beyond a certain range, and thus the overall shape of the cell block 100 may be maintained within a certain range.

[0066] The holding strap 140 may have locking devices at both ends in the length direction for stable connection with the side plate 130. The locking devices may be formed by bending both ends in the length direction of the holding strap 140. Meanwhile, locking grooves may be formed in the side plate 130 at positions corresponding to the locking devices, and the holding strap 140 and the side plate 130 may be stably connected through connection between the locking devices and the locking grooves.

[0067] The holding straps 140 may be made of various materials or through various manufacturing methods. For example, the holding straps 140 may be made of an elastic material, which allows the volumetric change of the battery cell stack 120 due to swelling to be within a certain range.

[0068] Meanwhile, the holding strap 140 is for fixing the relative position between the side plate 130 and the battery cell stack 120, and may be provided in a form different from that shown in the drawing, so long as its purpose as a 'fixing member' is achieved. For example, the fixing member may be provided in the form of a long bolt that can cross between the two side plates 130. The side plate 130 may have a groove into which the long bolt can be inserted, and the long bolt can fix the relative positions of the two side plates 130 by simultaneously connecting the two side plates 130 through the groove. The long bolt may be provided at an edge of the side plate 130, preferably at a position close to the apex of the side plate 130. Depending on the design, the holding strap 140 may be replaced by the long bolt described above, but both the holding strap 140 and the long bolt may be provided to the cell block.

[0069] The bus bar frame 150 may be located on one side of the battery cell stack 120 to cover one side of the battery cell stack 120 and guide the connection of the battery cell stack 120 to an external device. The bus bar frame 150 may be disposed on the front or rear side of the battery cell stack 120. A bus bar may be attached to the bus bar frame 150, and thus, an electrode lead of the battery cell stack 120 may be connected to the bus bar, thereby electrically connecting the battery cell stack 120 to an external device.

[0070] The bus bar frame 150 may include an electrically insulating material. The bus bar frame 150 may limit contact of the bus bar with other parts of the battery cell 110 other than the part connected to the electrode lead, thereby preventing an electrical short circuit from occurring.

[0071] The pack frame 200 may be for protecting the cell block 100 and electrical components connected thereto from external physical impacts. The pack frame 200 may accommodate the cell block 100 and electrical components connected thereto in an internal space of the pack frame 200. Here, the pack frame 200 includes an internal surface and an external surface, and the internal space of the pack frame 200 may be defined by the internal surface.

[0072] The pack frame 200 may be provided in a hollow shape that is open along one direction. For example, as shown in FIG 6, a plurality of cell blocks 100 may be positioned one after the other along the stacking direction of the battery cells 110, and the pack frame 200 may have a hollow shape that is open along the stacking direction.

[0073] The pack frame 200 may include a lower frame 210 and an upper frame 220. Here, the lower frame 210 may be provided in a plate shape, and the upper frame 220 may be provided in a U shape. At least one cell block 100 may be disposed on the plate-shaped lower frame 210, and the U-shaped upper frame 220 may be provided to surround the upper surface and two surfaces on the x-axis of the cell block 100. Also, any one of the upper frame 220 and the lower frame 210 may be formed to surround two surfaces on the y-axis of the battery pack 1000, and in this case, the end plate 400 may be omitted. However, the shape of the pack frame 200 shown in FIG. 6 is merely an example, and the pack frame 200 may be provided in a form different from that described above, such as a monoframe, a U-shaped lower frame 210, and a plate-shaped upper frame 220.

[0074] The pack frame 200 may include a portion having high thermal conductivity to rapidly release heat generated in the internal space to the outside. For example, at least a portion of the pack frame 200 may be made of a metal having high thermal conductivity, such as aluminum, gold, silver, copper, platinum, or an alloy including these metals. In addition, the pack frame 200 may have partial electrical insulation, and an insulating film may be provided or an insulating coating may be applied to a position where insulation is required. The portion of the pack frame 200 to which the insulating film or insulating coating is applied may be referred to as an insulating portion.

[0075] A resin layer 300 may be provided between the cell block 100 and the inner surface of the pack frame 200. The resin layer 300 may be provided between a bottom surface of the cell block 100 and the lower frame 210. The resin layer 300 may be provided between a top surface of the cell block 100 and the upper frame 220. The resin layer 300 may also be provided between a cooling member 500 (described later) and the upper frame 220.

[0076] The resin layer 300 may be formed by injecting a resin between the battery cell stack 120 and one side of the inner surfaces of the pack frame 200. However, this is not necessarily the case, and the resin layer 300 may be a member provided in a plate shape.

[0077] The resin layer 300 may be made of various materials, and the function of the resin layer 300 may vary depending on the material. For example, the resin layer 300 may be made of an insulating material, and the insulating resin layer 300 may prevent electron transfer between the cell block 100 and the pack frame 200. As another example, the resin layer 300 may be made of a thermally conductive material. The resin layer 300 made of a thermally conductive material may transfer heat generated in the battery cell 110 to the pack frame 200, thereby dissipating / transferring the heat to the outside. As another example, the resin layer 300 may include an adhesive material, thereby fixing the cell block 100 and the pack frame 200 to each other. As a specific example, the resin layer 300 may be provided to include at least one of a silicone-based material, a urethane-based material, and an acrylic-based material.

[0078] The end plate 400 may serve to protect the cell block 100 and electrical components connected thereto from external physical impacts by sealing the open sides of the pack frame 200. Each corner of the end plate 400 may be joined to a corresponding corner of the pack frame 200 by a method such as welding. Two end plates 400 may be provided to seal the two open sides of the pack frame 200, and may be made of a metal material having a predetermined strength.

[0079] The end plate 400 may have an opening 410 for exposing an inlet / outlet port 530 of a cooling member 500 described below, and may have a connector 420 for LV (Low voltage) connection or HV (High voltage) connection with an external device.

[0080] The cooling member 500 can be disposed on one side of the battery cell stack to release heat from the battery cells. The cooling member 500 can be disposed parallel to the stacking direction of the battery cell stack so as to be located close to a number of battery cells in the battery cell stack. Specifically, the cooling member 500 can be disposed on the top of the battery cell stack (in the +z-axis direction in FIG. 6 ). However, this is not necessarily the case, and the cooling member 500 may be disposed on the bottom (in the -z-axis direction) or the side (in the + / -y-axis direction) of the battery cell stack depending on the design.

[0081] The cooling member 500 may include an upper plate 510 and a lower plate 520 that form the outer shape of the cooling member 500, and an inlet / outlet port 530 that injects cooling water into the cooling member 500. The cooling member 500 may be formed by joining edges of the upper plate 510 and the lower plate 520. Cooling water may be stored or circulated between the upper plate 510 and the lower plate 520 that are joined together in the cooling member 500.

[0082] The upper plate 510 and the lower plate 520 may be provided in a plate shape. Although the upper plate 510 or the lower plate 520 is provided in a plate shape, the central portion may be recessed or indented to have a step with the edge portion. Specifically, the upper plate 510 or the lower plate 520 may have a concave shape based on the upper cross section in the width direction. This may be because the upper plate 510 or the lower plate 520 forms an internal space through the step to accommodate cooling water. Here, the width direction of the upper plate 510 or the lower plate 520 may be parallel to the short side of the upper plate 510 or the lower plate 520.

[0083] In order to improve the overall heat dissipation performance of the cooling member 500, the upper plate 510 or the lower plate 520 of the cooling member 500 may be made of a material with high thermal conductivity. The upper plate 510 and the lower plate 520 forming the outer shape of the cooling member 500 may be made of a metal with high rigidity, specific examples of which include aluminum, gold, silver, copper, platinum, or alloys containing these metals.

[0084] Meanwhile, in the drawings of this specification, the upper plate 510 is illustrated as a separate structure from the pack frame 200, but in order to reduce the weight of the battery pack 1000 or improve thermal conductivity, the upper plate 510 may be replaced by the upper surface of the pack frame 200, and the cooling member 500 may be provided in a structure integrated with the pack frame 200.

[0085] Coolant can be supplied through the inlet ports 532 arranged in parallel and discharged to the outlet port 534. The inlet port 532 and the outlet port 534 can be arranged in parallel on one end side of the cooling member 500. This can be for simplifying the design of the inflow and outflow of the cooling water supplied from the outside of the battery pack 1000. This can also be for minimizing the temperature difference between the vicinity of the inlet port 532 and the vicinity of the outlet port 534. Specifically, the cooling water flowing into the inlet port 532 can have the lowest temperature, and the cooling water discharged to the outlet port 534 can have the highest temperature. Therefore, if the inlet / outlet ports 530 are arranged adjacent to each other, heat exchange occurs between them, and the temperature deviation of the entire cooling water flowing in the internal space of the cooling member can be minimized. Therefore, by arranging the inlet / outlet ports 530 in parallel, the cooling member 500 can have a uniform heat dissipation performance overall.

[0086] Meanwhile, at least one weakened portion 600 may be formed in the cooling member 500 of the present embodiment.

[0087] The fragile portion 600 may refer to a portion that melts or breaks at a predetermined temperature or pressure. The fragile portion 600 is configured to be opened when an internal fire occurs in the battery pack 1000, thereby allowing cooling water to be immediately supplied to the fire site, and may be provided in various structures.

[0088] 9 to 11, for example, lower plate 520 may include at least one opening 521, which may be sealed by a sealing member 529. As shown in Fig. 10, sealing member 529 may seal opening 521 before a thermal runaway phenomenon to prevent the coolant from leaking out, and as shown in Fig. 11, sealing member 529 may melt or break after a thermal runaway phenomenon to allow the coolant in cooling member 500 to be injected toward battery cell 110.

[0089] In this embodiment, the fragile portion 600 may refer to a portion of the lower plate 520 where the opening 521 is located. The fragile portion 600 may refer to a portion of the lower plate 520 where the sealing member 529 is located. The fragile portion 600 may refer to a portion of the lower plate 520 where the opening 521 sealed by the sealing member 529 is formed.

[0090] The sealing member 529 can be made of a material that melts or breaks at a predetermined temperature or pressure. For example, the sealing member 529 can be made of a material having a melting point of 300° C. or less. As a specific example, the sealing member 529 can be made to include polyamide (PA). As another specific example, the sealing member 529 can be made to include a thermoplastic polymer resin having a melting point of 200° C. or less. Examples of the thermoplastic polymer resin include high density polyethylene (HDPE), polyethylene (PE), polypropylene (PP), polyphenylene oxide (PPO), and other materials having a melting point of about 100° C. or more and 200° C. or less.

[0091] The sealing member 529 may be provided in an I-shape. At least a portion of both ends of the sealing member 529 may be in surface contact with the upper and lower surfaces of the lower plate 520, thereby facilitating the joining of the sealing member 529 and the lower plate 520. Depending on the design, a raised or recessed protrusion or groove may be formed on the contact surface where the sealing member 529 and the lower plate 520 come into contact with each other. The protrusion or groove formed on the sealing member 529 and the groove or protrusion formed on the lower plate 520 engage with each other, thereby more effectively preventing the sealing member 529 from falling off due to the pressure of the cooling water.

[0092] Meanwhile, even if the cooling water is discharged from the cooling member 500 toward the battery cell 110 by opening the fragile portion 600, if the cooling water is not concentrated around the fire site, it may be difficult to quickly extinguish the fire. Therefore, the battery pack 1000 of the present embodiment may include a foam pad 700 that allows the cooling water to be concentrated around the fire site.

[0093] 12, a foam pad 700 may be disposed between the cooling member 500 and the cell block 100. The foam pad 700 may be disposed between the cooling member 500 and the battery cell stack 120.

[0094] The foam pad 700 may guide the flow of cooling water discharged from the cooling member 500 when the vulnerable portion 600 is opened. When thermal runaway occurs in the first battery cell 110A, only the vulnerable portion 600 around the position where thermal runaway occurs is opened, and the flow of the cooling water discharged through the opened vulnerable portion 600 is restricted by the foam pad 700 and can be concentrated on the first battery cell 110A. However, if the foam pad 700 is not present, the cooling water will spread widely on the upper surface of the battery cell stack 120, and as a result, it may be difficult to supply a sufficient amount of cooling water to the first battery cell 110A.

[0095] The foam pad 700 may include at least one pad opening 710. The pad opening 710 may correspond to the weak portion 600 of the cooling member 500. Since the pad opening 710 corresponds to the weak portion 600, the cooling water discharged from the weak portion 600 may be concentrated on the first battery cell 110A without being obstructed by the foam pad 700.

[0096] The foam pad 700 may be for absorbing a portion of the cooling water discharged from the cooling member 500. The foam pad 700 may be provided with a large number of pores and may absorb fluid through the pores. When the cooling water discharged from the cooling member 500 is absorbed by the foam pad 700, moisture remains around the first battery cell 110A, thereby enabling the first battery cell 110A to be quickly extinguished. In addition, the moisture remaining on the top of the first battery cell 110A may minimize the emission of particles or gas induced from the first battery cell 110A.

[0097] The foam pad 700 may correspond to the battery cell stacks 120 included in the battery pack 1000. When the battery pack 1000 includes a plurality of battery cell stacks 120, the foam pad 700 may correspond to the plurality of battery cell stacks 120. In this case, a plurality of foam pads 700 may be provided to correspond to each battery cell stack 120, or one foam pad may be provided to correspond to the plurality of battery cell stacks 120.

[0098] Hereinafter, a battery rack according to another embodiment of the present invention will be described.

[0099] The battery rack of the embodiment described below is the same as the above embodiment except for the structure of the cooling member included in the battery pack. Therefore, in describing this embodiment, the same reference numbers are used for the components common to the above embodiment, and detailed descriptions thereof will be omitted.

[0100] Fig. 13 is a perspective view showing a cooling member for a battery pack included in a battery rack according to another embodiment of the present invention, and Fig. 14 is a view showing a combination of a lower plate and a cover film included in the cooling member according to Fig. 13.

[0101] 13 and 14, the cooling member 500 of the present embodiment may include a cover film 580. The cover film 580 may be configured to close the opening 521 of the lower plate 520 before the battery cell 110 ignites and to open the opening 521 when the battery cell 110 ignites. When the cover film 580 is broken by the temperature and pressure caused by the battery cell ignition, the cooling water inside the cooling member 500 is injected toward the battery cell, thereby extinguishing the fire.

[0102] In this embodiment, the fragile portion 600 may refer to a portion of the lower plate 520 where the opening 521 is located. The fragile portion 600 may refer to a portion of the lower plate 520 where the opening 521 closed by the cover film 580 is formed.

[0103] The cover film 580 can be made from a material that melts or breaks at a predetermined temperature or at a predetermined pressure. The cover film 580 can be made from the same or similar material as the sealing member 529 of the previous embodiment.

[0104] The cover film 580 may be disposed between the upper plate 510 and the lower plate 520 and disposed to cover the lower plate 520. The cover film 580 may be attached to the lower plate 520. The outer shape of the cover film 580 may be similar or the same as the outer shape of the lower plate 520 as a whole. The specific shape of the cover film 580 may be similar or the same as the shape of the lower plate 520 except for the opening 521.

[0105] It is preferable that the cover film 580 has a certain thickness or more so that it can withstand gravity due to the weight of the cooling water and frictional force due to the flow of the cooling water, but if the cover film 580 is too thick, it may reduce the heat dissipation performance of the cooling member 500, so it is necessary to adjust the thickness to an appropriate value. The cover film 580 may be manufactured to a thickness of 2 mm or less, or 1.5 mm or less, but is preferably manufactured to a thickness of 0.5 to 1.0 mm when considering the durability of the cover film 580 and the reduction in heat dissipation performance due to the cover film 580. If the thickness of the cover film 580 is less than 0.5 mm, durability may be a problem, and if the thickness of the cover film 580 is more than 1.0 mm, the heat dissipation performance of the cooling member 500 may be reduced.

[0106] Since the cover film 580 is disposed by being coupled with the lower plate 520, the cooling water flows between the upper surface of the cover film 580 and the lower surface of the upper plate 510. Even if the cover film 580 is attached to the cooling member 500, the inflow and outflow of the cooling water through the inlet / outlet port 530 is not restricted by the cover film 580, so the cooling water in the cooling member 500 can be designed to be connected to an external cooling system 60 connected to the inlet / outlet port 530 to continuously circulate for the constancy of its temperature.

[0107] Meanwhile, when the sealing member 529 or the cover film 580 made of a material having a lower melting point than the lower plate 520 is provided to the cooling member 500, the cooling member 500 can include two kinds of materials with different physical properties. Conventionally, the upper plate 510 and the lower plate 520 of the cooling member 500 were mainly joined by brazing or laser welding, so when the cooling member 500 is designed to include two or more kinds of materials, there was a problem that one of the materials was deformed during the welding process, making the welding process difficult or impossible. In addition, when laser welding is used, a local temperature gradient may be formed in the upper plate 510 or the lower plate 520, which causes at least a portion of the upper plate 510 or the lower plate 520 to bend.

[0108] Therefore, in order to minimize such problems, the cooling member 500 of the present embodiment can be manufactured using a mechanical fastening method. The mechanical fastening method used in the manufacture of the present embodiment does not apply heat or applies heat at a temperature lower than the melting point of the material provided for the cooling member 500, thereby minimizing damage to the material forming the cooling member 500.

[0109] An example of a mechanical fastening method used in the cooling member 500 is a rivet, which is a connection using a fastening member. The cooling member 500 may include a number of fastening parts that are connected using a fastening member such as a rivet, and the lower plate 520 may have a fastening hole into which the fastening member is inserted. In FIG. 14, the positions of the fastening holes formed in the lower plate 520 or the cover film 580 are illustrated by dots.

[0110] Another example of a mechanical fastening method used for the cooling member 500 is clinching. Clinching is a deformation joining method in which a punch is used to press one side of two stacked plate-shaped members to deform their shape, thereby mechanically joining the two members. Considering the shape, clinching can also be called penetration joining.

[0111] In this way, if the mechanical fastening method is used instead of the welding method when manufacturing the cooling member 500, excessive heat is not generated during the manufacturing process, so that unintended deformation of the cooling member 500 can be minimized, and the difference between the pre-designed dimensions and the dimensions of the final product can be reduced, thereby ensuring dimensional stability. In particular, in the case of aluminum material that has been mainly used for the cooling member 500, it may start to deform when exposed to temperatures above its melting point of 660°C, but if the mechanical fastening method is used, heat above its melting point is not applied to the cooling member 500, so that the dimensional stability of the cooling member 500 can be further improved.

[0112] In addition, if a mechanical fastening method is applied when manufacturing the cooling member 500, certain materials that are sensitive to temperature may not be deformed during the manufacturing process, so that structures of various materials and shapes may be applied to the cooling member 500, and the design of the cooling member 500 may be easier and more diverse.

[0113] Meanwhile, when a mechanical fastening method is applied during the manufacture of the cooling member 500, an elastic member 590 can be disposed between the upper plate 510 and the lower plate 520 to further improve watertightness between the upper plate 510 and the lower plate 520. When a conventional welding method is applied, it is difficult to provide the elastic member 590, which is somewhat vulnerable to heat, when the upper plate 510 and the lower plate 520 are joined. Therefore, when a welding process is used, a sealant, etc. is applied through an additional process after the upper plate 510 and the lower plate 520 are joined in order to complement the watertightness of the welded surface. However, since the cooling member 500 according to the present embodiment is formed through a mechanical fastening method, the elastic member 590, which is vulnerable to heat, can be joined together during the process of joining the upper plate 510 and the lower plate 520, thereby achieving simplification of the manufacturing process and reduction in manufacturing costs.

[0114] The elastic member 590 may include a strip-shaped elastic member 592 disposed on an edge of the cooling member 500. The strip-shaped elastic member 592 may be provided on a surface where the upper plate 510 and the lower plate 520 contact each other, and may improve the watertightness of the upper plate 510 and the lower plate 520. The strip-shaped elastic member 592 may be compressed by an external force when the upper plate 510 and the lower plate 520 are joined together, thereby filling a gap between the upper plate 510 and the lower plate 520. The strip-shaped elastic member 592 may prevent the cooling water inside the cooling member 500 from leaking out through the gap. Here, the strip-shaped elastic member 592 may also be called a water pad.

[0115] The elastic member 590 may include a ring-shaped elastic member 594. When the cooling member 500 is formed by a rivet or the like, a fastening hole is formed at the fastening portion, which may reduce the watertightness of the cooling member 500. However, the watertightness of the fastening portion can be complemented by the ring-shaped elastic member 594. When the cover film 580 is provided to the cooling member 500, the ring-shaped elastic member 594 may be disposed on the cover film 580, and the watertightness of the cooling member 500 can be improved by sealing the gap around the fastening portion. Here, the ring-shaped elastic member 594 may be referred to as a 'water ring'.

[0116] The elastic member 590 can be made of a flexible material having elasticity. Examples of materials from which the elastic member 590 can be made include a silicone-based foam pad, an acrylic-based foam pad, and a urethane-based foam pad.

[0117] Hereinafter, a battery rack according to another embodiment of the present invention will be described.

[0118] The battery rack of the embodiment described below is the same as the above-mentioned embodiment except for the structure of the cooling member included in the battery pack. Therefore, in describing this embodiment, the same reference numbers are used for the configurations common to the above-mentioned embodiment, and detailed descriptions thereof will be omitted.

[0119] Fig. 15 is a perspective view showing a lower plate of a cooling member for a battery pack included in a battery rack according to another embodiment of the present invention. Fig. 16 is a view showing an example of an AA cross section of Fig. 15. Fig. 17 is a cross-sectional view of a lower plate for explaining a modified example of the cooling member according to Fig. 15. Fig. 18 is a cross-sectional view of a lower plate for explaining another modified example of the cooling member according to Fig. 15. Fig. 19 is a cross-sectional view of a cooling member for explaining yet another modified example of the cooling member according to Fig. 15.

[0120] 15 to 19, the fragile portion 600 of this embodiment may be a portion having a relatively smaller thickness than other portions of the lower plate 520. Specifically, the lower plate 520 may have a first portion called the fragile portion 600 and a second portion where the fragile portion 600 is not formed, and here the thickness of the second portion may be greater than the thickness of the first portion. The thickness of the first portion may be less than half the thickness of the second portion. By having a thickness somewhat smaller than other portions, the fragile portion 600 can be broken relatively easily by heat or pressure.

[0121] 15, the lower plate 520 of the cooling member 500 according to the present embodiment may include at least one groove 522. The groove 522 may be a portion formed to be thin so as to be easily broken by high temperature or high pressure when the battery cell ignites. Therefore, in the present embodiment, the fragile portion 600 may refer to the portion of the lower plate 520 where the groove 522 is formed or the groove 522.

[0122] In the above embodiment, the cooling water is located between the upper plate 510 and the lower plate 520 and directly contacts the lower plate 520 having the fragile portion 600 formed therein, so there is a problem that the cooling water may leak through the gap around the opening 521. In addition, manufacturing the lower plate 520 to include two materials with different physical properties involves a complicated manufacturing process, which may increase the manufacturing time and manufacturing costs. However, in the cooling member 500 of the present embodiment, the sealing member 529 or the cover film 580 having a low melting point is not disposed on the lower plate 520, and the opening 521 is not formed in the lower plate 520, so that it is possible to reduce watertightness and simplify the manufacturing process.

[0123] Referring to FIG. 16, the cross section of the groove 522 may have various shapes. The groove 522 may have a rectangular cross section as shown in FIG. 16(a) by vertically connecting a first portion where the groove 522 is formed and a second portion where the groove 522 is not formed. In addition, when a slope is formed on the connecting surface between the first and second portions, a part of the lower plate 520 may have a triangular cross section as shown in FIG. 16(b) or a trapezoidal cross section as shown in FIG. 16(d). When a connecting surface between the first and second portions is formed to have a curvature, a part of the lower plate 520 may have a rounded cross section as shown in FIG. 16(c). Meanwhile, the cross section of the lower plate 520 formed by the groove 522 is not limited to the above example, and may be variously modified in consideration of ease of design, etc.

[0124] Considering that the fragile portion 600 must be broken by heat or temperature, it is preferable that the fragile portion 600 includes as many thin portions as possible, so the other shapes of Fig. 16 may be more preferable than the shape of Fig. 16(b). However, since the temperature and pressure at which the fragile portion 600 breaks can be affected by factors such as thickness, physical properties, shape, etc., the other shapes of Fig. 16 may not necessarily be more preferable than the shape of Fig. 16(b).

[0125] 17, grooves 522 formed in lower plate 520 may be exposed to the outside, not facing the inside of cooling member 500. In this case, the bottom surface of cooling member 500 may have a locally protruding shape, and the protruding bottom surface of cooling member 500 may be located close to or in contact with the battery cell, thereby promoting heat dissipation from the battery cell. The cross-sectional shape shown in FIG. 17 can be described with reference to the content of FIG. 16, except that the top and bottom directions are reversed, and detailed description thereof will be omitted.

[0126] Meanwhile, the groove 522 of the present embodiment can be formed in various ways.

[0127] For example, the grooves 522 can be formed by partially etching the bottom plate 520. The grooves 522 can be formed using a notching process.

[0128] As another example, the bottom plate 520 can be formed by bonding two layers together, thereby forming the weakened portion 600 or groove 522 .

[0129] 18, the lower plate 520 can be formed by joining a first layer 520A provided as a plate-shaped mold member and a second layer 520B having a number of holes. The grooves 522 or the weakened portions 600 can be formed by holes formed in the second layer 520B. For reference, the shaded portion in FIG. 18, excluding the first layer 520A, represents the second layer 520B, and the partially empty spaces between the shaded portions represent cross sections of the holes formed in the second layer 520B.

[0130] A portion of the lower plate 520 may have a relatively large thickness by including the first layer 520A and the second layer 520B, and another portion of the lower plate 520 may have a relatively small thickness by including only the first layer 520A. Here, the portion having the first layer 520A may be referred to as the first portion, and the portion having both the first layer 520A and the second layer 520B may be referred to as the second portion. Thus, the thickness of the first portion may correspond to the thickness of the first layer 520A, and the thickness of the second portion may correspond to the thickness of the first layer 520A and the second layer 520B.

[0131] Meanwhile, when the fragile portion 600 is formed by bonding two layers as shown in FIG. 18 compared to when the fragile portion 600 is formed through a notching process, the dimensional stability of the fragile portion 600 is improved, and the process costs and process time due to defective products can be minimized.

[0132] Specifically, when the groove 522 is formed through an etching process, the equipment used therefor may be difficult to control with a precise level, and when the thickness of the lower plate 520 is thin or when the desired thickness of the fragile portion 600 is thin, the lower plate 520 may be damaged in the process of forming the groove 522. Specifically, in order to provide the fragile portion 600 in the lower plate 520, a part of the already sufficiently thin lower plate 520 must be removed to form a thickness at the level of a thin film, and if the control of the equipment is not perfect, the lower plate 520 may be damaged or the dimensional stability of the fragile portion 600 may decrease, resulting in an increase in defective products, and thus wasting process costs and process time.

[0133] When the lower plate 520 is formed by bonding two layers, the thickness of each layer can be freely adjusted, so that the fragile portion 600 can be formed sufficiently thin. The first layer 520A forming the fragile portion 600 can be provided as an aluminum material that can melt or break due to temperature, pressure, or sparks during a thermal runaway phenomenon, and in this case, the thickness of the first layer 520A can be designed to be sufficiently thick to a level at which it can melt due to thermal runaway of the battery cell. Specifically, the first layer 520A can be provided with a thickness of 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, 0.2 mm or less, or 0.1 mm or less.

[0134] For example, when the first layer 520A and the second layer 520B are both made of aluminum, the first layer 520A may be made of an aluminum plate having a thickness of 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, 0.2 mm or less, or 0.1 mm or less, and the second layer 520B may be made of an aluminum plate having a thickness of 1.0 to 1.5 mm or more with holes formed therein. In addition, depending on the embodiment, the first layer 520A may be made even thinner, for example, an aluminum plate having a thickness of 0.03 to 0.07 mm, or 0.04 to 0.06 mm, or 0.05 mm. In this way, when the aluminum plate of the second layer 520B is bonded to one side of the first layer 520A, a lower plate 520 having a weak portion 600 with a sufficiently thin thickness can be formed.

[0135] Also, when the lower plate 520 is formed by bonding two layers, all of the weakened portions 600 may have the same thickness. When the first and second weakened portions are formed in the lower plate 520, the thicknesses of the first and second weakened portions may be substantially the same. The thickness value of each weakened portion 600 may not vary depending on its position. If thickness deviation occurs depending on the position in the weakened portion 600, some of the weakened portions may be formed thicker than designed, and therefore the particular portion may be less likely to break due to heat or pressure. In this embodiment, all of the weakened portions 600 are formed to have a uniform thickness, so that the error between the design and the actual product should be minimized.

[0136] Various bonding processes can be used to bond the two layers that form the lower plate 520. Since cooling water is located on the upper surface of the lower plate 520, the bond between the two layers must be firm.

[0137] As an example, the bond between the two layers can be formed through a welding process. Examples of the welding process used for the bond include brazing or laser welding. The two layers can be melt-bonded by applying a temperature level similar to the melting point of the material to the two layers. Through the melt-bonding, the watertightness of the lower plate 520 can be achieved at a desired level.

[0138] As another example, the bond between the two layers can be formed through a rolling process. The rolling process is a method of bonding two layers by passing a laminate in which two or more layers are stacked between a pair of rolls. During interlayer bonding through the rolling process, the laminate can be heated. If the heating temperature is equal to or higher than the recrystallization temperature of the metal, it can be called hot rolling, and if the heating temperature is lower than the recrystallization temperature, it can be called cold rolling. By applying pressure and / or heat to the laminate, a wide bonding surface between the two layers can be formed, thereby ensuring sufficient watertightness of the lower plate 520.

[0139] On the other hand, when the lower plate 520 is formed by bonding two layers, the materials of the two layers may be different from each other, or may be the same or similar to each other. If the materials of the two layers are the same or similar to each other, the melting points of the two layers are the same / similar to each other, so that the above-mentioned bonding process involving heat or pressure should be performed more easily.

[0140] Meanwhile, when joining two layers through a brazing process, the joining process may not be performed smoothly depending on the physical properties or melting point of the metal. For example, if the two layers are made of a single type of aluminum, if the brazing process temperature is set to 660°C, which is the melting point of aluminum, deformation of the aluminum layer may occur during the joining process. To prevent such deformation of the layers, the first layer 520A or the second layer 520B can be manufactured from a clad metal, which is a double-layered metal material.

[0141] For example, the layers are bonded through a brazing process, and the first layer 520A is located below the second layer 520B, so that the cross section of the lower plate 520 can be similar to that shown in FIG. 16. Here, the first layer 520A may be 3000 series aluminum, and the second layer 520B may be a clad metal including 3000 series and 4000 series aluminum. Since the second layer 520B includes a clad metal, the temperature of the brazing process can be set to about 600°C, thereby preventing the aluminum from deforming during the bonding process. In this case, the upper plate 510 may be 3000 series aluminum.

[0142] As another example, the layers are bonded through a brazing process, and the first layer 520A is located above the second layer 520B, so that the cross section of the lower plate 520 can be provided with a structure similar to that of FIG. 17. Here, the first layer 520A can include 3000-series and 4000-series clad metals, and the second layer 520B can include 3000-series aluminum. In this case, the upper plate 510 can also be 3000-series aluminum, and the bonding between the layers can be smoothly performed through the 4000-series aluminum formed on the upper and lower surfaces of the first layer 520A provided as a clad metal. Alternatively, the first layer 520A can be provided as 3000-series aluminum, and the second layer 520B or the upper plate 510 can be provided as 3000-series and 4000-series clad metals.

[0143] 19, the cooling member 500 can be described as having three layers. Specifically, the upper plate 510 of the cooling member 500 can have one layer, and the lower plate 520 can have two layers. Here, the lower plate 520 having two layers has been fully described above, so a detailed description will be omitted.

[0144] In the cooling member 500, the cooling water is contained between the upper plate 510 and the lower plate 520, so the flow rate deviation of the cooling water can be determined according to the separation distance between the upper plate 510 and the lower plate 520. The flow rate deviation of the cooling member 500 can depend on the thickness difference of the lower plate 520. Specifically, the flow rate per unit length may be relatively large around the first portion where the weak portion 600 is formed, and the flow rate per unit length may be relatively small around the second portion where the weak portion 600 is not formed. If the flow rate around the first portion is larger, the cooling water is injected more quickly by hydraulic pressure when the weak portion 600 is opened, so the larger the flow rate around the first portion, the more preferable it is.

[0145] Therefore, in this embodiment, an upper plate 510 having a bent portion 514 may be provided so that a flow rate deviation of the cooling water in the cooling member 500 is formed. The bent portion 514 may have a corrugated cross-sectional shape based on a longitudinal upper cross-section of the cooling member 500. Here, based on the cross-section, the highest point, i.e., a crest, of the bent portion 514 may correspond to a first portion of the lower plate 520 in which the weak portion 600 is formed. Also, the lowest point, i.e., a trough, of the bent portion 514 may correspond to a second portion of the lower plate 520. Since the crest of the bent portion 514 corresponds to the first portion, the flow rate per unit length around the first portion can be increased, and when the weak portion 600 is opened, the cooling water in the cooling member 500 can be injected more quickly toward the first battery cell 110A in which the ignition phenomenon has occurred.

[0146] 19, the layers of the cooling member 500 are arranged in the order of the first layer 520A, the second layer 520B, and the upper plate 510, but it is also possible to arrange them in the order of the second layer 520B, the first layer 520A, and the upper plate 510. In this case, the second layer 520B forming the lower surface of the cooling member 500 is located close to the battery cells or can be in contact with the battery cells, so that the second layer 520B should have the effect of promoting heat dissipation from the battery cells.

[0147] In addition, in the cooling member 500 as shown in FIG. 19, the upper plate 510 may be referred to as the third layer and may be made of aluminum. When the third layer is made of aluminum, the upper plate 510 is preferably formed to a thickness of 1.0 to 2.0 mm, 1.3 to 1.7 mm, or 1.5 mm. In addition, the second layer 520B included in the lower plate 520 is preferably formed to a thickness of 1.0 to 1.5 mm, 1.2 to 1.4 mm, or 1.3 mm. The first layer 520A may have a thickness of 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, 0.2 mm or less, or 0.1 mm or less. In addition, the first layer 520A may be formed thin enough to have the characteristics of the fragile portion 600, and may have a thickness of 0.03 to 0.07 mm, or 0.04 to 0.06 mm.

[0148] In the cooling member 500 having three layers, various bonding processes such as a welding process, a rolling process, etc. can be applied to bond the layers together. In the cooling member 500 including three layers, when the layers are bonded through brazing, the physical properties of the first layer 520A, the second layer 520B, and the third layer which is the upper plate 510 can be explained above, so detailed explanation will be omitted.

[0149] Hereinafter, a battery rack according to another embodiment of the present invention will be described.

[0150] The battery rack of the embodiment described below is the same as the above-mentioned embodiment except for the structure of the cooling member included in the battery pack. Therefore, in describing this embodiment, the same reference numbers are used for the configurations common to the above-mentioned embodiment, and detailed descriptions thereof will be omitted.

[0151] Fig. 20 is a perspective view showing a cooling member of a battery pack included in a battery rack according to another embodiment of the present invention. Fig. 21 is a top view of the cooling member according to Fig. 20. Fig. 22 is a view showing a connection between a lower plate, a cooling tube, and a cooling hose included in the cooling member according to Fig. 20. Fig. 23 is a view showing the cooling member according to Fig. 21 cut along line BB, showing cooling water flowing into and out of the cooling tube and cooling hose. Fig. 24 is a cross-sectional view of the cooling member according to Fig. 21 cut along line BB, showing the introduction of cooling water through the cooling hose when a battery cell catches fire.

[0152] 20 to 24, the cooling member 500 of the present embodiment may include cooling tubes 540 and cooling hoses 550 through which cooling water flows. The lower plate 520 is preferably provided in a plate shape to support the cooling tubes 540, etc. The upper plate 510 may be omitted and replaced by the cooling tubes 540, etc. The cooling member 500 may be manufactured by attaching the cooling tubes 540 to the upper surface of the lower plate 520, attaching the cooling hoses 550 to the cooling tubes 540, and then combining the fixing member 560 with the lower plate 520.

[0153] In the above embodiment, since the cooling water is located between the upper plate 510 and the lower plate 520 and directly contacts the lower plate 520 having the weak portion 600 formed thereon, there is a problem that the cooling water may leak through the gap around the opening 521. In addition, manufacturing the lower plate 520 to include two materials with different physical properties involves a complicated manufacturing process, which may increase the manufacturing time and manufacturing costs. However, in the cooling member 500 of the present embodiment, the cooling water is isolated in the cooling tube 540 or the cooling hose 550, so that the decrease in watertightness due to the opening 521 can be minimized. In addition, by connecting the lower plate 520 to the cooling tube 540 and the cooling hose 550 through the fixing member 560, the manufacturing process of the cooling member 500 can be simplified, and the manufacturing time and cost can be reduced.

[0154] Referring to FIG. 22, the lower plate 520 may include at least one opening 521. The opening 521 may be for injecting internal cooling water to the battery cell by heat or pressure generated by ignition when the battery cell ignites internally. A protrusion 524 may be formed around the lower plate 520, extending from one side of the lower plate 520 and continuously positioned along one corner of the lower plate 520. The protrusion 524 may be disposed in contact with or adjacent to an electrode lead of each battery cell stack or a bus bar connected to the electrode lead, thereby promoting heat dissipation of the corresponding portion. In addition, a bank portion 526 may be formed on the lower plate 520. The bank portion 526 may extend along the length of the cooling member 500 at the upper center in the width direction of the cooling member 500 except for a predetermined section. The bank portion 526 allows the cooling tube 540 to be mounted at a fixed position and the fixing member 560 to be stably fixed. Here, the width direction of the cooling member 500 may be parallel to the short side of the cooling member 500. The length direction of the cooling member 500 may be a direction parallel to the long side of the cooling member 500 .

[0155] 22 and 23, the cooling tube 540 can provide a flow path of coolant for dissipating heat from the battery cell. Coolant injected through an inlet port 532 is accommodated inside the cooling tube 540, and the coolant accommodated in the cooling tube 540 can be discharged through an outlet port 534. The cooling member 500 can be maintained at a relatively constant temperature as the coolant flows in and out of the cooling tube 540. The coolant in the cooling tube 540 can be designed to be continuously circulated by being connected to an external cooling system 60 connected to the inlet / outlet port 530 to maintain the temperature constant.

[0156] The lower plate 520 cooled by the cooling tube 540 can promote heat dissipation of the battery cells. The cooling tube 540 can be made of a material with high thermal conductivity, which can rapidly absorb heat from the lower plate 520. The cooling tube 540 can be made of a material with sufficient rigidity to withstand the pressure and weight of the cooling water contained therein. The cooling tube 540 can be made of the same material as the lower plate 520 or a similar material. Examples of materials for the cooling tube 540 include aluminum, gold, silver, copper, platinum, and alloys containing these metals.

[0157] The cooling tube 540 may be attached to the lower plate 520 at a position where the bank portion 526 is not formed. The outer shape of the cooling tube 540 may be similar to the outer shape of the lower plate 520 except for the protrusion 524.

[0158] The cooling tube 540 may have a square tube shape and may branch into two parts corresponding to the inlet port 532 and the outlet port 534, respectively, in consideration of the position of the bank portion 526. Thus, the cooling tube 540 may form a U-shaped flow path. The cooling tube 540 may include a first portion 542 extending from the inlet port 532 along a straight line parallel to the length direction of the cooling member 500, a second portion 544 extending from an end of the first portion 542 along a curve rotating in a clockwise or counterclockwise direction, and a third portion 546 extending from an end of the second portion 544 toward the outlet port 534 along a straight line parallel to the length direction of the cooling member 500.

[0159] The cooling tube 540 may include a receiving portion 548 in which the cooling hose 550 is attached. The receiving portion 548 may refer to a receiving space in the cooling tube 540 in which the cooling hose 550 is attached. The receiving portion 548 may be a long groove extending along the length of the cooling member 500, and the cross section of the receiving portion 548 may be a polygon such as a square or a circle. Both ends of the cooling hose 550 may be connected to both ends of the receiving portion 548 in the length direction. Both ends of the cooling hose 550 may be inserted into both ends of the receiving portion 548 in the length direction. The connection portions between both ends of the receiving portion 548 in the length direction and both ends of the cooling hose 550 may be sealed to ensure watertightness. For example, a gasket may be provided at the connection portion between the cooling hose 550 and the receiving portion 548, and watertightness between the two members may be ensured through the gasket. As another example, the cooling hose 550 may have an extension extending in a circumferential direction from the end of the cooling hose 550 at both ends, and the extension is inserted into the end of the receiving portion 548 and positioned inside the cooling tube 540 to complement the connection between the cooling hose 550 and the cooling tube 540. As another example, the cooling hose 550 may have an end formed with a first extension extending in a circumferential direction and a second extension spaced apart from the first extension. The first extension may be positioned inside the cooling tube 540, and the second extension may be positioned outside the cooling tube 540, and the two extensions may be in close contact with the cooling tube 540 to further complement the connection between the cooling hose 550 and the cooling tube 540. In addition, a protrusion may be formed on the extension, the first extension, or the second extension, and the extension may be further in close contact with one side of the cooling tube 540 through the protrusion.

[0160] The cooling hose 550 is connected to the cooling tube 540 and can provide a flow path for the coolant that dissipates heat from the battery cell. The coolant flowing in from the inlet / outlet port 530 can move through the cooling hose 550. The cooling hose 550 can receive the coolant from the cooling tube 540 located close to the inlet / outlet port 530.

[0161] The fixing member 560 may be for complementing the rigidity of the cooling member 500 by fixing the cooling tubes 540 and the cooling hoses 550 to the lower plate 520. The fixing member 560 may fix the positions of the cooling tubes 540 and the cooling hoses 550 through bonding with the lower plate 520.

[0162] The fixing member 560 may be provided in the form of a strap having a length. The fixing member 560 may be arranged parallel to the width direction of the cooling member 500. A plurality of fixing members 560 may be provided along the length direction of the cooling member 500, and the plurality of fixing members 560 may be arranged at uniform intervals.

[0163] The fixing member 560 can be made of a highly rigid material in order to maintain the shape of the cooling member 500, and as an example, can be made of metal.

[0164] The fixing member 560 may be connected to both ends of the cooling member 500 in the width direction. The fixing member 560 may be connected to the center of the cooling member 500 in the width direction. The fixing member 560 may include end connecting parts 562 formed at both ends of the fixing member 560 in the length direction, respectively, and a center connecting part 564 formed at the center of the fixing member 560 in the length direction. The end connecting parts 562 of the fixing member 560 may be connected to the protrusions 524 located at both ends of the lower plate 520 in the width direction. The center connecting part 564 of the fixing member 560 may be connected to the bank part 526 located at the center of the lower plate 520 in the width direction. The end connecting parts 562 and the center connecting part 564 may be formed to have a step with other parts of the fixing member 560, and may have a height slightly lower than other parts of the fixing member 560. Considering the shapes of the protrusion 524 and the bank 526 , the end joint 562 may be formed to have a larger step than the central joint 564 .

[0165] In this manner, when the fixing member 560 is used in manufacturing the cooling member 500, excessive heat is not generated during the manufacturing process compared to a joining method using a welding process, and therefore a specific material that is vulnerable to temperature may not be deformed during the manufacturing process. Therefore, by using the fixing member 560, the cooling member 500 can be manufactured to include two or more materials with different properties, and structures of various materials and shapes, such as the cooling hose 550, can be applied to the cooling member 500, and the design of the cooling member 500 may be easier and more diverse.

[0166] 24, the cooling hose 550 can be disposed to correspond to the opening 521 of the lower plate 520. The cooling hose 550 can be melted or broken when an internal fire occurs, thereby injecting internal cooling water toward the battery cell. When a battery cell catches fire, a part of the cooling hose 550 corresponding to the opening 521 is opened by melting or breaking, and thus the cooling water is sprayed, ejected, or injected in the direction of gravity, thereby extinguishing the fire in the battery cell located below the cooling member 500. Meanwhile, in order to achieve this effect, the receiving portion 548 to which the cooling hose 550 is attached must also be formed to correspond to the opening 521 of the lower plate 520.

[0167] Considering the structure of this embodiment, the weak portion 600 of this embodiment may refer to a portion of the lower plate 520 where the opening 521 is located. The weak portion 600 may refer to a portion of the lower plate 520 where the opening 521 closed by the cooling hose 550 is formed.

[0168] The cooling hose 550 can be made from a material that melts or breaks at a predetermined temperature or at a predetermined pressure. The cooling hose 550 can be made from the same or similar material as the sealing member 529 of the previous embodiment.

[0169] Meanwhile, in order to achieve the above-mentioned effect, it is also possible to configure the cooling tube 540 so that the cooling water is introduced by breaking a part of the cooling tube 540 without separately manufacturing the cooling hose 550. However, since the cooling tube 540 must be manufactured from a material having sufficient rigidity in order to withstand the pressure of the cooling water flowing inside and maintain its shape, there is a problem that the overall durability of the cooling member 500 may be reduced if the cooling tube 540 is manufactured from a material that melts in heat or is easily broken by pressure. Therefore, it is preferable to configure the cooling hose 550, which is easily broken by heat, separately from the cooling tube 540 as in this embodiment in order to improve the performance of the entire cooling member 500.

[0170] Meanwhile, the battery pack included in the embodiment of the present invention may additionally include a battery management system (BMS) for managing the temperature, voltage, etc. of the battery and / or a cooling device.

[0171] 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]

[0172] 1: Power storage device 10: Battery rack 11: Rack frame 20: Exhaust manifold 40: Inlet manifold 60: Cooling system 1000: Battery pack 2000: Water Tank 100: Cell Block 110: Battery cell 120: Battery cell stack 130: Side plate 140: Holding strap 150: Busbar frame 200: Pack Frame 300: Resin layer 400: End plate 500: Cooling material 510: Upper plate 520: Lower plate 530: Inlet / Outlet Ports 540: Cooling tube 550: Cooling hose 560: Fixing member 580: Cover film 590: Elastic member 600: Weakened part 700: Foam pad

Claims

1. At least one battery pack and a rack frame on which the battery pack is mounted; The battery pack a battery cell stack in which a plurality of battery cells are stacked; A pack frame that houses the battery cell stack; and a cooling member located on an upper side of the battery cell stack and containing cooling water; The cooling member is connected to a water tank mounted on the rack frame, At least one fragile part is formed on the lower plate of the cooling member, the fragile part being broken or melted when the temperature or pressure exceeds a predetermined value, A battery rack, wherein when the weak portion of the cooling member is opened and the level of the cooling water becomes low, cooling water is supplied from the water tank to the cooling member.

2. The battery rack of claim 1 , wherein the water tank is located on an upper portion of the rack frame.

3. the cooling member includes an inlet port and an outlet port for injecting cooling water into an internal space; the inlet port and the outlet port are connected to an external cooling system; The battery rack according to claim 1 or 2, wherein cooling water for the cooling member circulates through the inlet port and the outlet port.

4. the inlet port is connected to the cooling system through an inlet manifold; the outlet port is connected to the cooling system through an exhaust manifold; The battery rack of claim 3 , wherein the water tank is coupled to a drain manifold.

5. 3. The battery rack according to claim 1, wherein the battery pack is a plurality of battery packs, and the water tank is connected to each of the cooling members included in the plurality of battery packs.

6. A number of openings are formed in a lower plate of the cooling member, and the openings are closed by a sealing member; The battery rack according to claim 1 or 2, wherein the weakened portion is a portion of the lower plate where the opening closed by the sealing member is located.

7. the cooling member includes a cooling tube that provides a flow path for cooling water and a cooling hose attached to the cooling tube; The lower plate is formed with a number of openings, and the cooling hoses are positioned to correspond to the openings. The battery rack according to claim 1 or 2, wherein the weak portion is a portion of the lower plate where the opening closed by the cooling hose is located.

8. The battery rack according to claim 7 , wherein the lower plate and the cooling tube are connected by a strap-shaped fastening member.

9. the lower plate includes a first portion in which the weak portion is formed and a second portion in which the weak portion is not formed, The battery rack according to claim 1 or 2, wherein a thickness value of the first portion is smaller than a thickness value of the second portion.

10. 10. The battery rack of claim 9, wherein the thickness value of the first portion is less than or equal to half the thickness value of the second portion.

11. The lower plate is formed by bonding a first layer and a second layer having different thicknesses; a thickness of the first portion corresponds to a thickness of the first layer; 10. The battery rack of claim 9, wherein a thickness of the second portion corresponds to a thickness of the first layer and the second layer.

12. an upper plate coupled to the lower plate of the cooling member includes a bent portion; The crest of the bent portion corresponds to the first portion, The battery rack of claim 9 , wherein a valley of the bend corresponds with the second portion.

13. The battery rack according to claim 1 or 2, wherein an upper plate of the cooling member is integrated with the pack frame.

14. 3. An electrical power storage device comprising at least one battery rack according to claim 1 or 2.

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