Devices that contain cooling systems

Abstract

A device according to one embodiment of the present invention is a device having at least one battery pack attached thereto, the battery pack including a battery cell stack having a plurality of stacked battery cells, a pack frame accommodating 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 located inside the device, and a lower plate of the cooling member being formed with at least one weak portion that breaks or melts at a predetermined temperature or pressure or higher, and when the weak portion of the cooling member is opened to cause the level of the cooling water to drop, 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. 10-2022-0030250 filed on March 10, 2022 and Korean Patent Application No. 10-2023-0023100 filed on February 21, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a device including a cooling system, and more particularly to a device including a cooling system capable of preventing a chain reaction of thermal runaway phenomena in a battery pack. [Background technology]

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

[0004] Currently commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Of these, lithium secondary batteries are attracting 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] In the case of secondary batteries used in medium- to large-sized devices such as automobiles, medium- to large-sized battery modules or battery packs in which a number of battery cells are electrically connected are 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 it is also possible to directly attach the battery cell to the battery pack. Since it is preferable that the battery module or battery pack is manufactured to be small in size and weight, if possible, prismatic batteries, pouch-type batteries, and the like that can be stacked with a high degree of integration and have a small weight relative to the 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 becomes higher than the appropriate temperature due to overcharging or the like, the performance may be degraded, and if the temperature rises excessively, there is a risk of explosion or fire. If a fire occurs in at least one battery pack among the battery packs, the flames and heat may spread to the neighboring battery packs, leading to additional fires and causing problems such as property damage and serious injury to human life.

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

[0008] Therefore, there is a need for the development of an electric vehicle that includes a cooling system that can supply a sufficient amount of cooling water in the event of a fire in at least one of the battery packs, thereby preventing the spread of flames and heat to an adjacent battery pack. 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 device including a cooling system that can inject a sufficient amount of cooling water at an appropriate time and place in the event of an internal fire in at least one of the battery packs.

[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 device according to one embodiment of the present invention is a device having at least one battery pack attached thereto, the battery pack including a battery cell stack having a plurality of stacked battery cells, a pack frame accommodating 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 located inside the device, and a lower plate of the cooling member being formed with at least one weak portion that breaks or melts at a predetermined temperature or pressure or higher, and when the weak portion of the cooling member is opened to cause the level of the cooling water to drop, cooling water is supplied from the water tank to the cooling member.

[0012] The cooling water in the water tank can be supplied based on an electrical signal from a control unit that controls the operation of the water tank.

[0013] The cooling water in the water tank may be supplied by a pump that operates based on the electrical signal.

[0014] The water tank is located above the battery pack, and cooling water in the water tank can be supplied to the cooling member by a pressure difference between the cooling member and the water tank.

[0015] The water tanks may include a first water tank located at the front side of the device and a second water tank located at the rear side.

[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 tube may 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. Effect of the Invention

[0024] According to the embodiment, cooling water can be injected from the cooling member inside the battery pack into the battery cell where thermal runaway has occurred, and at this time, a sufficient amount of cooling water is supplied from the water tank to the cooling member, thereby quickly extinguishing the internal fire and preventing further thermal runaway.

[0025] 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]

[0026] [Figure 1] 1 is a side view of an electric vehicle according to an embodiment of the present invention. [Diagram 2] 2 is a diagram for explaining a case where a water tank included in the electric vehicle in FIG. 1 is of a manual type. FIG. [Diagram 3] 1 is a perspective view of a battery pack included in an electric vehicle according to an embodiment of the present invention; [Figure 4] 4 is an exploded perspective view of a battery pack included in the electric vehicle shown in FIG. 3. [Diagram 5] 4 is an exploded perspective view of a battery pack included in the electric vehicle shown in FIG. 3. [Figure 6] 4 is a perspective view of a cell block included in the battery pack shown in FIG. 3. [Figure 7] 4 is a view showing a lower plate of a cooling member included in the battery pack shown in FIG. 3. [Figure 8] 1A and 1B are diagrams for explaining changes in a cooling member before and after a thermal runaway phenomenon. [Figure 9] 1A and 1B are diagrams for explaining changes in a cooling member before and after a thermal runaway phenomenon. [Figure 10] 4 is a diagram for explaining changes that occur after a thermal runaway phenomenon occurs when a foam pad is provided in the battery pack shown in FIG. 3. FIG. [Figure 11] 11 is a perspective view showing a cooling member of a battery pack included in an electric vehicle according to another embodiment of the present invention. [Figure 12]12 is a view showing a combination of a lower plate and a cover film included in the cooling member shown in FIG. 11. [Figure 13] 11 is a perspective view showing a lower plate of a cooling member of a battery pack included in an electric vehicle according to another embodiment of the present invention. FIG. [Figure 14] FIG. 14 is a diagram showing an example of the AA cross section of FIG. 13. [Figure 15] 14 is a cross-sectional view of a lower plate for explaining a modified example of the cooling member shown in FIG. 13. [Figure 16] 14 is a cross-sectional view of a lower plate for explaining another modified example of the cooling member shown in FIG. 13. FIG. [Figure 17] 16 is a cross-sectional view of a cooling member for explaining still another modified example of the cooling member in FIG. 15. FIG. [Figure 18] 11 is a perspective view showing a cooling member of a battery pack included in an electric vehicle according to another embodiment of the present invention. [Figure 19] FIG. 19 is a top view of the cooling member according to FIG. [Figure 20] 19 is a diagram showing the connection between a lower plate included in the cooling member shown in FIG. 18 and a cooling tube and a cooling hose. [Figure 21] FIG. 20 shows the cooling member of FIG. 19 cut along line BB, illustrating the flow of cooling water into and out of the cooling tubes and cooling hoses. [Figure 22] FIG. 20 is a cross-sectional view of the cooling member in FIG. 19 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

[0027] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the embodiments. The present invention may be embodied in various different forms other than those described below, and the scope of the present invention is not limited to the embodiments described herein.

[0028] In order to clearly describe the present invention, parts unnecessary for the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0029] 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.

[0030] In addition, when a layer, film, region, plate, or other part 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, or other part is "directly on" the other part, but also the case where there is another part therebetween. Conversely, when a layer, film, region, plate, or other part is described as being "directly on" the other part, it means 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, being "on" or "above" another part, as well as being described as being "on" or "above" another part, should also be understood with reference to the above content.

[0031] In addition, because the top / bottom of a particular component may be determined differently depending on the reference direction, throughout this specification, "top" or "bottom" is defined to mean the two surfaces of that component that face each other along the z-axis.

[0032] In addition, throughout the specification, when a part "comprises" a certain element, this does not mean to exclude other elements, but means that other elements may also be included, unless specifically stated to the contrary.

[0033] Furthermore, throughout the specification, "on a plane" means when the part in question is viewed from above, and "on a cross section" means when the part in question is cut vertically and viewed from the side.

[0034] An electric vehicle according to an embodiment of the present invention will be described below.

[0035] Fig. 1 is a side view of an electric vehicle according to an embodiment of the present invention, and Fig. 2 is a view for explaining a case where a water tank included in the electric vehicle according to Fig. 1 is a manual type.

[0036] Referring to Figures 1 and 2, an electric vehicle 1 of this embodiment may include a battery pack 1000, a water tank 2000 that supplies additional cooling water to the battery pack 1000, and a cooling water supply pipe 3000 that connects the battery pack 1000 and the water tank 2000.

[0037] 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 cooling water is injected. By providing the cooling member 500 as a water-cooled type, 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.

[0038] The cooling water used in the cooling member 500 may be any one of known types or a mixture thereof, and any one of known types may be used as long as it can dissipate heat from the battery cells by moving along a flow path inside the cooling member 500. However, if the cooling water has electrical conductivity, problems may occur due to electrical conduction, so it is preferable that the cooling water has electrical insulation. In this case, the electrically insulating cooling water may include cooling water having low electrical conductivity, for example, electrical conductivity of 150 uS / cm.

[0039] Meanwhile, in order to effectively suppress a fire in a battery cell, it is 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 can 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 extending from the water tank only when a battery cell fire is confirmed by a sensor.

[0040] 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 these operations must not cause errors, and even if they operate normally, they must go through many decision 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 to stop the rapid and continuous thermal runaway phenomenon in the conventional water injection system. Therefore, in this embodiment, a fragile part (600, see FIG. 8, 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.

[0041] 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 this 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 effectively suppressed. Therefore, the electric vehicle 1 of this embodiment may include a water tank 2000 that can supply additional cooling water to the cooling member 500.

[0042] The water tank 2000 may be connected to the battery pack 1000 through a cooling water supply pipe 3000. When the electric vehicle 1 includes a plurality of battery packs 1000, the water tank 2000 may be connected to each battery pack 1000. When additional cooling water is required, the cooling water in the water tank 2000 may be supplied to the cooling member 500 through the cooling water supply pipe 3000.

[0043] As a specific example, the cooling water in the cooling member 500 according to this embodiment may be designed to be continuously circulated by being connected to an external heat exchanger connected to an inlet port (532, see FIG. 4) and an outlet port (534, see FIG. 4) in order to maintain the temperature constant. The cooling water may be circulated in the order of the inlet port 532, the cooling member 500, the outlet port 534, and the heat exchanger. In this case, since the cooling water circulates along a closed circuit and the level of the cooling water in the cooling member 500 is maintained constant, 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 heat exchanger.

[0044] However, if an ignition occurs inside the battery pack 1000, the cooling water in the cooling member 500 may be injected into the battery pack 1000 due to the opening of the fragile portion 600, and the water level inside the cooling member 500 may decrease. At this time, the cooling water in the water tank 2000 is supplied to the cooling member 500 through the cooling water supply pipe 3000, so that additional cooling water can be injected into the battery pack 1000, and the ignition of the battery pack 1000 can be effectively suppressed.

[0045] In this manner, the water tank 2000 and the cooling water supply pipe 3000 included in the electric vehicle 1 are used to mitigate thermal runaway of the battery pack 1000, and can be collectively referred to as a "cooling system." Alternatively, the cooling system can be described as including not only the water tank 2000 and the cooling water supply pipe 3000, but also the cooling member 500 included in the battery pack 1000.

[0046] The water tank 2000 may be provided in an active structure. The active structure means that the supply of cooling water from the water tank 2000 is performed based on an electrical signal. For this purpose, the water tank 2000 may include or be connected to a controller that generates an electrical signal. That is, the cooling system may include a controller. The controller may receive a sensing value from a sensor unit that detects a thermal runaway phenomenon of the battery pack 1000 or detects a change in the water level of the cooling member 500. When a preset sensing value is detected by the sensor unit, the controller may generate an electrical signal based on the detection, thereby causing cooling water to be supplied to the battery pack 1000. In this case, the sensor unit may be included in the battery pack 1000.

[0047] Here, the cooling water supply pipe 3000 may be designed to be openable and closable by an electrical signal, and may be opened by an electrical signal from the control unit to allow the cooling water in the water tank 2000 to be supplied to the cooling member 500. Alternatively, the water tank 2000 may be designed to be openable and closable by an electrical signal.

[0048] When the water tank 2000 is provided in an active structure, the cooling system may include a pump. The pump can be driven based on an electrical signal, and the cooling water in the water tank 2000 can be supplied to the cooling member 500 of the battery pack 1000 by driving the pump.

[0049] 1 shows the water tank 2000 including the first water tank 2100 located at the front and the second water tank 2200 located at the rear, but if the cooling system includes a pump, the water tank 2000 may be disposed in any space of the electric vehicle 1. The water tank 2000 may include only the first water tank 2100 or the second water tank 2200, or the water tank 2000 may be provided in a location other than that shown.

[0050] The water tank 2000 may be provided in a manual structure, which means that the supply of cooling water in the water tank 2000 is based on gravity or water pressure difference (pressure difference) rather than on an electrical signal.

[0051] The water tank 2000 provided in the manual type structure may not include or be connected to a control unit or pump, thereby further simplifying the structure of the cooling system.

[0052] The position of the water tank 2000 provided in the manual type structure may be limited. Specifically, the water tank 2000 provided in the manual type structure needs to be disposed above the battery pack 1000. If the water tank 2000 is disposed above, when the water level in the cooling member 500 decreases, cooling water can be supplied from the water tank 2000 to the cooling member 500 by gravity or a water pressure difference (pressure difference) without a separate electrical signal.

[0053] Referring to FIG. 2, the electric vehicle 1 may run on flat ground, but may also run on or stop on an incline. In this case, if the electric vehicle 1 includes only the first water tank 2100, it may be difficult to supply cooling water from the first water tank 2100 to the cooling member 500 on a downhill road as shown in FIG. 2(b) even if the water level in the cooling member 500 is low. In contrast, if the electric vehicle 1 includes only the second water tank 2200, it may be difficult to supply cooling water from the second water tank 2200 to the cooling member 500 on an uphill road as shown in FIG. 2(a). Therefore, if the water tank 2000 provided in the electric vehicle 1 is a manual type, it is preferable that the water tank 2000 includes both the first water tank 2100 located at the front of the electric vehicle 1 and the second water tank 2200 located at the rear of the electric vehicle 1.

[0054] Hereinafter, a battery pack included in an electric vehicle according to an embodiment of the present invention will be described in more detail.

[0055] 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.

[0056] In this case, since the battery module includes a module frame that forms the outer surface of the battery module, 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 reduces reassembly when some battery cells are defective. 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.

[0057] As a result, the battery cell stack of this embodiment is 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 allows the structure of the battery pack to be simplified, and advantages can be obtained in terms of the manufacturing cost and manufacturing process, and the weight of the battery pack can be reduced. In addition, this allows the battery cell stack to be positioned closer to the cooling member in the pack frame, making it easier to dissipate heat through the cooling member.

[0058] 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 this embodiment can be referred to as a battery module as necessary.

[0059] Fig. 3 is a perspective view of a battery pack included in an electric vehicle according to an embodiment of the present invention. Figs. 4 and 5 are exploded perspective views of the battery pack included in the electric vehicle according to Fig. 3. Fig. 6 is a perspective view of a cell block included in the battery pack according to Fig. 3. Fig. 7 is a view showing a lower plate of a cooling member included in the battery pack according to Fig. 3. Figs. 8 and 9 are views for explaining changes in a cooling member before and after a thermal runaway phenomenon. Fig. 10 is a view for explaining changes after a thermal runaway phenomenon when a foam pad is provided in the battery pack according to Fig. 3.

[0060] 3 to 6, 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 in a state where some of the above-mentioned components are omitted or in a state where other components not mentioned are added depending on the design.

[0061] The battery pack 1000 according to this embodiment may include a cell block 100 that is not sealed by a frame or the like. The cell block 100 may be similar to a conventional battery module in which the module frame is omitted, and thus may be referred to as a battery module with an "open structure" or a "moduleless structure".

[0062] 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 surfaces of the battery cell stack 120.

[0063] Each battery cell 110 may include an electrode assembly, a cell case, and an electrode lead protruding from the electrode assembly. The battery cells 110 may be provided in a pouch type or a square type that can maximize the number of cells stacked per unit area. Meanwhile, although the positive and negative leads of the battery cell 110 are shown to protrude in opposite directions in Figs. 3 to 6, this is not necessarily the case, and the electrode leads of the battery cell 110 may protrude in the same direction.

[0064] 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 "axial direction" is interpreted to include both + / - directions) as shown in Figures 3 to 6.

[0065] Meanwhile, by arranging the battery cells 110 in one direction, the electrode leads of the battery cells 110 may be located on one surface of the battery cell stack 120, or on both the one surface and the other surface facing the one surface. In this manner, the surface of the battery cell stack 120 on which the electrode leads are located is referred to as the front surface or rear surface of the battery cell stack 120, and the front and rear surfaces of the battery cell stack 120 are shown as two surfaces facing each other on the x-axis in Figures 3 to 6. In addition, the surface of the battery cell stack 120 on which the outermost battery cells 110 are located is referred to as the side surface of the battery cell stack 120, and the side surfaces of the battery cell stack 120 are shown as two surfaces facing each other on the y-axis.

[0066] The side plate 130 may be provided to maintain the overall shape of the battery cell stack 120. The side plate 130 is a plate-shaped member, and can complement the rigidity of the cell block 100 in place of a module frame. The side plate 130 can be disposed at 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.

[0067] The side plate 130 may be made of various materials and may be provided through various manufacturing methods. As one example, the side plate 130 may be made of a plastic material manufactured by injection molding. As another example, the side plate 130 may be made of a leaf spring material. As still another example, the side plate 130 may be made of an elastic material so that a part of its shape can be deformed in response to a volume change of the battery cell stack 120 due to expansion.

[0068] 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 positioned 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. In this way, the holding straps 140 can 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 can be maintained within a certain range.

[0069] The holding strap 140 may have hooks at both ends in the length direction for stable connection with the side plate 130. The hooks may be formed by bending both ends in the length direction of the holding strap 140. Meanwhile, the side plate 130 may have hook grooves at positions corresponding to the hooks, and the holding strap 140 and the side plate 130 can be stably connected through connection between the hooks and the hook grooves.

[0070] 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 expansion to a certain extent.

[0071] 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 drawings, so long as the purpose of the holding strap 140 as a "fixing member" can be achieved. For example, the fixing member may be provided in the form of a long bolt that can traverse between the two side plates 130. The side plate 130 may be provided with 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 on the periphery of the side plate 130, preferably near the apex of the side plate 130. Depending on the design, the holding strap 140 may be replaced with the long bolt described above, or both the holding strap 140 and the long bolt may be provided to the cell block.

[0072] The bus bar frame 150 may be located on one surface of the battery cell stack 120 to cover one surface of the battery cell stack 120 and to guide a connection between the battery cell stack 120 and an external device. The bus bar frame 150 may be located on a front or rear surface of the battery cell stack 120. A bus bar may be attached to the bus bar frame 150, whereby an electrode lead of the battery cell stack 120 is connected to the bus bar, thereby electrically connecting the battery cell stack 120 to an external device.

[0073] The bus bar frame 150 may include an electrically insulating material. The bus bar frame 150 can limit contact between the bus bar and other parts of the battery cell 110 other than the part joined to the electrode lead, thereby preventing an electrical short circuit from occurring.

[0074] The pack frame 200 may be for protecting the cell block 100 and electrical equipment connected thereto from external physical shocks. The pack frame 200 may accommodate the cell block 100 and electrical equipment 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.

[0075] The pack frame 200 may be provided in a hollow form that is open along one direction. For example, as shown in Fig. 4, a plurality of cell blocks 100 may be positioned consecutively along the stacking direction of the battery cells 110, and the pack frame 200 may have a hollow form that is open along the stacking direction.

[0076] 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, since the shape of the pack frame 200 shown in FIG. 4 is merely an example, 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.

[0077] The pack frame 200 may include a portion having high thermal conductivity in order to quickly 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 requiring insulation. 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.

[0078] 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.

[0079] The resin layer 300 may be formed by injecting a resin between the battery cell stack 120 and one side of the inner surface 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.

[0080] 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.

[0081] 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.

[0082] The end plate 400 may have an opening 410 for exposing an inlet / outlet port 530 of the cooling member 500 described later, and may have a connector 420 attached thereto for LV (low voltage) connection or HV (high voltage) connection with an external device.

[0083] The cooling member 500 may be disposed on one side of the battery cell stack to release heat from the battery cells. The cooling member 500 may be disposed parallel to the stacking direction of the battery cell stack so as to be located close to a number of battery cells of the battery cell stack. Specifically, the cooling member 500 may be located at the top of the battery cell stack (in the +z-axis direction in FIG. 4). However, this is not necessarily the case, and the cooling member 500 may be located at the bottom (-z-axis upward direction) or the side (+ / -y-axis upward direction) of the battery cell stack depending on the design.

[0084] 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 inside of the cooling member 500. The cooling member 500 may be formed by joining the peripheries 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 to form the cooling member 500.

[0085] The upper plate 510 and the lower plate 520 may be provided in a plate shape. Alternatively, the upper plate 510 or the lower plate 520 may be provided in a plate shape, but the central portion may be recessed or indented to have a step with respect to the peripheral portion. Specifically, the upper plate 510 or the lower plate 520 may have a recess shape based on a cross section in the width direction. In this case, the upper plate 510 or the lower plate 520 may form an internal space through a 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.

[0086] 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 provided with a material having high thermal conductivity. The upper plate 510 and the lower plate 520 forming the outer shape of the cooling member 500 may be manufactured with a metal having high rigidity, specific examples of which include aluminum, gold, silver, copper, platinum, and alloys containing these metals.

[0087] Meanwhile, in the drawings of this specification, the upper plate 510 is shown 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 substituted for 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.

[0088] Cooling water may be supplied through the inlet ports 532 arranged side by side and discharged to the outlet port 534. The inlet port 532 and the outlet port 534 may be arranged side by side in parallel on one end side of the cooling member 500. This may be for simplifying the design of the inflow and outflow of the cooling water supplied from the outside of the battery pack 1000. This may 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 may have the lowest temperature, and the cooling water discharged to the outlet port 534 may have the highest temperature. Therefore, when the inlet / outlet ports 530 are arranged adjacent to each other, heat exchange occurs between them, thereby minimizing the temperature deviation of the entire cooling water flowing in the internal space of the cooling member. Therefore, by arranging the inlet / outlet ports 530 side by side, the cooling member 500 may have an overall uniform heat dissipation performance.

[0089] Meanwhile, at least one weakened portion 600 may be formed in the cooling member 500 of this embodiment.

[0090] 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.

[0091] 7 to 9, for example, the lower plate 520 may include at least one opening 521, which may be sealed by a sealing member 529. As shown in Fig. 8, the sealing member 529 may seal the opening 521 before a thermal runaway phenomenon to prevent the coolant from flowing out, and as shown in Fig. 9, the sealing member 529 may melt or break after a thermal runaway phenomenon to allow the coolant in the cooling member 500 to flow toward the battery cell 110.

[0092] 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.

[0093] The sealing member 529 may be made of a material that melts or breaks at a predetermined temperature or pressure. For example, the sealing member 529 may be made of a material having a melting point of 300° C. or less. As a specific example, the sealing member 529 may be made to include polyamide (PA). As another specific example, the sealing member 529 may be made to include a thermoplastic polymer resin having a melting point of 200° C. or less. Examples of the thermoplastic polymer resin include substances having a melting point of about 100° C. or more and 200° C. or less, such as high density polyethylene (HDPE), polyethylene (PE), polypropylene (PP), and polyphenylene oxide (PPO).

[0094] 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, so that the sealing member 529 and the lower plate 520 can be easily coupled together. Depending on the design, a convex or concave protrusion or groove may be formed on the contact surface where the sealing member 529 and the upper and lower surfaces of the lower plate 520 come into contact with each other. The protrusion or groove formed on the sealing member 529 engages with the groove or protrusion formed on the lower plate 520, so that the sealing member 529 can be more effectively prevented from falling off due to the pressure of the cooling water.

[0095] Meanwhile, even if the cooling water is discharged from the cooling member 500 toward the battery cells 110 due to the opening of 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 this embodiment may include a foam pad 700 that allows the cooling water to concentrate around the fire site.

[0096] 10, a foam pad 700 may be located between the cooling member 500 and the cell block 100. The foam pad 700 may be located between the cooling member 500 and the battery cell stack 120.

[0097] The foam pad 700 may be for guiding 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 the 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 in the first battery cell 110A. However, if the foam pad 700 is not present, the cooling water may spread widely on the upper surface of the battery cell stack 120, which may make it difficult to supply a sufficient amount of cooling water to the first battery cell 110A.

[0098] 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 can be concentrated on the first battery cell 110A without being blocked by the foam pad 700.

[0099] The foam pad 700 may be for absorbing a portion of the cooling water discharged from the cooling member 500. The foam pad 700 is provided with a large number of pores and can absorb fluid through the pores. When the cooling water discharged from the cooling member 500 is absorbed by the foam pad 700, moisture may remain around the first battery cell 110A, thereby quickly achieving fire extinguishing of the first battery cell 110A. In addition, the release of particles or gas that may be induced from the first battery cell 110A due to moisture remaining on the top of the first battery cell 110A may be minimized.

[0100] The foam pad 700 may correspond to the battery cell stack 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 the respective battery cell stacks 120, or one foam pad may be provided to correspond to the plurality of battery cell stacks 120.

[0101] An electric vehicle according to another embodiment of the present invention will now be described.

[0102] The electric vehicle 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 components common to the above-mentioned embodiment, and detailed description will be omitted.

[0103] Fig. 11 is a perspective view showing a cooling member of a battery pack included in an electric vehicle according to another embodiment of the present invention, and Fig. 12 is a view showing a combination of a lower plate and a cover film included in the cooling member according to Fig. 11.

[0104] 11 and 12, the cooling member 500 of this 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.

[0105] 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.

[0106] The cover film 580 may be made of a material that melts or breaks at a predetermined temperature or pressure. The cover film 580 may be made of the same or similar material as the sealing member 529 of the previous embodiment.

[0107] The cover film 580 may be disposed between the upper plate 510 and the lower plate 520 and may be positioned 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.

[0108] The cover film 580 preferably has a thickness greater than a certain value so as to withstand the gravity caused by the weight of the cooling water and the frictional force caused by 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 needs to be adjusted to an appropriate thickness. The thickness of the cover film 580 may be manufactured to 2 mm or less, or 1.5 mm or less, but considering the durability of the cover film 580 and the reduction in heat dissipation performance caused by the cover film 580, it is preferable to manufacture the cover film 580 to a thickness of 0.5 to 1.0 mm. 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, it may reduce the heat dissipation performance of the cooling member 500.

[0109] Since the cover film 580 is disposed by being coupled with the lower plate 520, cooling water can flow between the upper surface of the cover film 580 and the lower surface of the upper plate 510. In addition, even though the cover film 580 is attached to the cooling member 500, the inflow and outflow of 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 may be designed to be connected to an external heat exchanger connected to the inlet / outlet port 530 to continuously circulate in order to maintain its temperature constant.

[0110] 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 may include two materials having 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, and when the cooling member 500 is designed to include two or more materials, one of the materials may be 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 may cause at least a portion of the upper plate 510 or the lower plate 520 to bend.

[0111] Therefore, in order to minimize such problems, the cooling member 500 of this embodiment may be manufactured through a mechanical fastening method. The mechanical fastening method used in the manufacture of this 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.

[0112] An example of a mechanical fastening method used for the cooling member 500 is a rivet, which is a connection through a fastening member. The cooling member 500 may include a number of fastening parts that are connected through fastening members such as rivets, and the lower plate 520, etc. may be formed with fasteners into which the fastening members can be inserted. In FIG. 12, the positions of the fasteners formed on the lower plate 520 or the cover film 580 are illustrated as dots.

[0113] 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 or the like is used to press one side of two stacked plate-shaped members to deform their shape, thereby mechanically joining the two members. Clinching can be called a penetration joining method in consideration of its shape.

[0114] In this way, when 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, so that dimensional stability can be ensured. In particular, in the case of aluminum material that has been mainly used for the cooling member 500, it starts to deform when temperatures above its melting point of 660°C are applied, but when the above-mentioned mechanical fastening method is applied, heat above the melting point is not applied to the cooling member 500, so that the dimensional stability of the cooling member 500 can be further improved.

[0115] In addition, when a mechanical fastening method is applied during the manufacture of 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 can be applied to the cooling member 500, making the design of the cooling member 500 easier and more diverse.

[0116] Meanwhile, when a mechanical fastening method is applied during the manufacture of the cooling member 500, an elastic member 590 may be positioned between the upper plate 510 and the lower plate 520 in order to further improve the watertightness between the upper plate 510 and the lower plate 520. When the conventional welding method is applied, it is difficult to provide the elastic member 590, which is somewhat vulnerable to heat, during the bonding of the upper plate 510 and the lower plate 520. Therefore, when a welding process is used, a sealant or the like is applied through an additional process after bonding the upper plate 510 and the lower plate 520 in order to complement the watertightness of the welded surface. However, since the cooling member 500 according to the embodiment is formed through a mechanical bonding method, the elastic member 590, which is vulnerable to heat, can be bonded together during the bonding process of the upper plate 510 and the lower plate 520, thereby achieving simplification of the manufacturing process and reduction of manufacturing costs.

[0117] The elastic member 590 may include a band-type elastic member 592 disposed on the periphery of the cooling member 500. The band-type 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 band-type elastic member 592 may be compressed by an external force when the upper plate 510 and the lower plate 520 are combined, thereby filling a gap existing between the upper plate 510 and the lower plate 520. The band-type elastic member 592 may prevent the cooling water inside the cooling member 500 from leaking out through the gap. Here, the band-type elastic member 592 may be referred to as a water pad.

[0118] 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 fastener 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 located 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".

[0119] The elastic member 590 may be made of a flexible material having elasticity. Examples of the material that the elastic member 590 is made of include a silicone-based foam pad, an acrylic-based foam pad, and a urethane-based foam pad.

[0120] An electric vehicle according to another embodiment of the present invention will now be described.

[0121] The electric vehicle 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 components common to the above-mentioned embodiment, and detailed description will be omitted.

[0122] Fig. 13 is a perspective view showing a lower plate of a cooling member of a battery pack included in an electric vehicle according to another embodiment of the present invention. Fig. 14 is a view showing an example of an AA cross section of Fig. 13. Fig. 15 is a cross-sectional view of a lower plate for explaining a modified example of the cooling member according to Fig. 13. Fig. 16 is a cross-sectional view of a lower plate for explaining another modified example of the cooling member according to Fig. 13. Fig. 17 is a cross-sectional view of a cooling member for explaining yet another modified example of the cooling member according to Fig. 15.

[0123] 13 to 17, the weakened portion 600 of this embodiment may be a portion having a thickness value relatively smaller than other portions of the lower plate 520. Specifically, the lower plate 520 may have a first portion called the weakened portion 600 and a second portion where the weakened portion 600 is not formed, and the thickness of the second portion may be greater than the thickness of the first portion. The thickness value of the first portion may be less than half the thickness value of the second portion. By having a thickness value somewhat smaller than other portions, the weakened portion 600 can be relatively easily pierced by heat or pressure.

[0124] 13, the lower plate 520 of the cooling member 500 according to this 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 this 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 itself.

[0125] In the above-described 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 fragile portion 600 formed therein, 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, which has a low melting point, is not located on the lower plate 520, and the opening 521 is not formed in the lower plate 520, so that it is possible to achieve a reduction in watertightness and a simplification of the manufacturing process.

[0126] Referring to FIG. 14, the cross section of the groove 522 may have various shapes. The groove 522 may have a rectangular cross section as shown in FIG. 14(a) by vertically connecting a first portion in which the groove 522 is formed and a second portion in which the groove 522 is not formed. In addition, when an inclination is formed on the connection surface between the first portion and the second portion, a part of the lower plate 520 may have a triangular cross section as shown in FIG. 14(b) or a trapezoidal cross section as shown in FIG. 14(d). When the connection surface between the first portion and the second portion is formed to have a curvature, a part of the lower plate 520 may have a rounded cross section as shown in FIG. 14(c). Meanwhile, the cross section of the lower plate 520 formed by the groove 522 is not limited to the above-mentioned examples, and may be variously modified in consideration of ease of design, etc.

[0127] Considering that the fragile portion 600 should be broken by heat or temperature, it is preferable that the fragile portion 600 includes as many thin portions as possible, and therefore the other shapes of Fig. 14 are more preferable than the shape of Fig. 14(b). However, since the temperature and pressure at which the fragile portion breaks can be affected by factors such as thickness, physical properties, shape, etc., the other shapes of Fig. 14 are not necessarily more preferable than the shape of Fig. 14(b).

[0128] 15, the grooves 522 formed in the lower plate 520 may be exposed to the outside, not facing the inside of the cooling member 500. In this case, the lower surface of the cooling member 500 may have a locally protruding shape, and the protruding lower surface of the 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. 15 can be described with reference to the content of FIG. 14, except that the top and bottom directions are reversed, and detailed description thereof will be omitted.

[0129] Meanwhile, the grooves 522 of this embodiment may be formed in various ways.

[0130] For example, the grooves 522 may be formed by partially etching the bottom plate 520. The grooves 522 may be formed using a notching process.

[0131] As another example, the bottom plate 520 may be formed by bonding two layers together, which may form the weakened portion 600 or groove 522 .

[0132] 16, the lower plate 520 may 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 described above may be formed by holes formed in the second layer 520B. For reference, the shaded portions in FIG. 16, except for the first layer 520A, represent the second layer 520B, and the partially empty spaces between the shaded portions represent cross sections of holes formed in the second layer 520B.

[0133] 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.

[0134] Meanwhile, when the fragile portion 600 is formed by bonding two layers as shown in FIG. 16 compared to when the fragile portion 600 is formed through a notching process, etc., the dimensional stability of the fragile portion 600 is improved, and the process costs and process time due to defective products can be minimized.

[0135] 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 needs to 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.

[0136] 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 may be provided with 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 may be designed to be sufficiently thick to a level at which it melts due to thermal runaway of the battery cell. Specifically, the first layer 520A may 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.

[0137] For example, when both the first layer 520A and the second layer 520B are 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 thinner, for example, an aluminum plate having a thickness of 0.03 to 0.07 mm, 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.

[0138] Also, when the lower plate 520 is formed by bonding two layers, all 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 have deviations depending on its position. If thickness deviations depending on the position occur in the weakened portions 600, some of them may be formed thicker than designed, and as a result, certain portions may be difficult to break due to heat or pressure. In this embodiment, all the weakened portions 600 are formed to have a uniform thickness, so that the error between the design and the actual product can be minimized.

[0139] Various bonding processes may 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 needs to be firm.

[0140] As an example, the two layers may be bonded through a welding process. Examples of the welding process used for the bonding include brazing and laser welding. The two layers can be fused together by applying a temperature level similar to the melting point of the material to the two layers. Through the fusion bonding, the watertightness of the lower plate 520 can be achieved to a desired level.

[0141] As another example, the bond between the two layers may 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 by the rolling process, the laminate is 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.

[0142] 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. When 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 can be performed more easily.

[0143] Meanwhile, when bonding two layers through a brazing process, the bonding process may not be performed smoothly depending on the physical properties or melting points of the metals. For example, if the two layers are made of a single type of aluminum, setting the temperature of the brazing process to 660°C, which is the melting point of aluminum, may cause deformation of the aluminum layer during the bonding process. To prevent such deformation of the layers, the first layer 520A or the second layer 520B may be manufactured from a clad metal, which is a double-layered metal material.

[0144] 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 provided with a structure similar to that shown in FIG. 14. 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 may be set to about 600° C., thereby preventing deformation of the aluminum during the bonding process. In this case, the upper plate 510 may be 3000 series aluminum.

[0145] In 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. 15. Here, the first layer 520A may include 3000-series and 4000-series clad metals, and the second layer 520B may include 3000-series aluminum. In this case, the upper plate 510 may 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 may be provided as 3000-series aluminum, and the second layer 520B or the upper plate 510 may be provided as 3000-series and 4000-series clad metals.

[0146] 17, 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 thereof will be omitted.

[0147] 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 may be determined depending on the separation distance between the upper plate 510 and the lower plate 520. The flow rate deviation of the cooling member 500 may 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 fragile portion 600 is formed, and the flow rate per unit length may be relatively small around the second portion where the fragile portion 600 is not formed. If the flow rate around the first portion is larger, the cooling water can be injected more quickly due to water pressure when the fragile portion 600 is opened, so it is preferable that the flow rate around the first portion is larger.

[0148] Accordingly, 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 cross section in the longitudinal direction 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. By having the crest of the bent portion 514 correspond to the first portion, the flow rate per unit length around the first portion can be increased, and the cooling water of the cooling member 500 can be injected more quickly toward the first battery cell 110A in which the ignition phenomenon has occurred when the weak portion 600 is opened.

[0149] 17, the layers of the cooling member 500 are shown to be 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 may be located close to the battery cells or may be in contact with the battery cells, so that the second layer 520B may have the effect of promoting heat dissipation from the battery cells.

[0150] Also, in the cooling member 500 as shown in FIG. 17, the upper plate 510 is called 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. Also, 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. Also, 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.

[0151] In cooling member 500 having three layers, the layers may be bonded using various bonding processes such as a welding process, a rolling process, etc. In cooling member 500 including three layers, when the layers are bonded through brazing, the physical properties of first layer 520A, second layer 520B, and third layer which is upper plate 510 can be explained in accordance with the above content, and therefore detailed explanation will be omitted.

[0152] An electric vehicle according to another embodiment of the present invention will now be described.

[0153] The electric vehicle 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 components common to the above-mentioned embodiment, and detailed description will be omitted.

[0154] Fig. 18 is a perspective view showing a cooling member of a battery pack included in an electric vehicle according to another embodiment of the present invention. Fig. 19 is a top view of the cooling member according to Fig. 18. Fig. 20 is a view showing a connection between a lower plate included in the cooling member according to Fig. 18 and a cooling tube and a cooling hose. Fig. 21 is a view showing the cooling member according to Fig. 19 cut along line BB, and showing how cooling water flows into and out of the cooling tube and the cooling hose. Fig. 22 is a cross-sectional view of the cooling member according to Fig. 19 cut along line BB, and showing the injection of cooling water through the cooling hose when a battery cell catches fire.

[0155] 18 to 22, the cooling member 500 of this 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-like form 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 an 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.

[0156] 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.

[0157] Referring to FIG. 20, the bottom plate 520 may include at least one opening 521 .

[0158] The opening 521 may be for injecting internal cooling water to the battery cell by heat or pressure generated by the 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 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 from the corresponding portion. In addition, a berm 526 may be formed on the lower plate 520. The berm 526 may extend along the length of the cooling member 500 at the center of the width of the cooling member 500 except for a predetermined section. The berm 526 may attach the cooling tube 540 at a correct position and stably fix the fixing member 560. 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 parallel to the long side of the cooling member 500.

[0159] 20 and 21, the cooling tube 540 may provide a flow path of coolant for dissipating heat from the battery cell. The inside of the cooling tube 540 may receive coolant injected through the inlet port 532, and the coolant contained in the cooling tube 540 may be discharged through the outlet port 534. The cooling member 500 may 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 may be designed to be connected to an external heat exchanger connected to the inlet / outlet port 530 and continuously circulated in order to maintain the homeostasis of its temperature.

[0160] The lower plate 520 cooled by the cooling tube 540 can promote heat dissipation of the battery cells. The cooling tube 540 may be made of a material with high thermal conductivity, thereby quickly absorbing heat from the lower plate 520. The cooling tube 540 may be made of a material having sufficient rigidity to withstand the pressure and weight of the cooling water contained therein. The cooling tube 540 may 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.

[0161] The cooling tube 540 may be attached to the lower plate 520 at a position where the berm 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.

[0162] The cooling tube 540 may have a square tube shape and may be branched into two parts corresponding to the inlet port 532 and the outlet port 534, respectively, taking into account the position of the berm 526. This allows the cooling tube 540 to 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 along a curve rotating clockwise or counterclockwise at an end of the first portion 542, 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.

[0163] The cooling tube 540 may include a receiving portion 548 to which the cooling hose 550 is attached. The receiving portion 548 may refer to a receiving space in the cooling tube 540 to 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 rectangle or a circle. Both ends of the cooling hose 550 in the length direction 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 is provided at the connection portion between the cooling hose 550 and the receiving portion 548, and watertightness between the two members can be ensured through the gasket. As another example, both ends of the cooling hose 550 may be formed with circumferentially extending extensions at the ends of the cooling hose 550, and the extensions may be inserted into the ends of the receiving parts 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 end of the cooling hose 550 may be formed with a first extension extending in the 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, in this case, the extensions, the first extension, or the second extension, may be formed with protrusions, and may be more closely connected to one side of the cooling tube 540 through the protrusions.

[0164] The cooling hose 550 is connected to the cooling tube 540 and may provide a flow path for coolant to dissipate heat from the battery cell. The coolant flowing in from the inlet / outlet port 530 may move through the cooling hose 550. The cooling hose 550 may be supplied with coolant from the cooling tube 540 located close to the inlet / outlet port 530.

[0165] 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.

[0166] The fixing member 560 may be provided in the form of a strap having a length. The fixing member 560 may be located 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.

[0167] The fixing member 560 may be made of a highly rigid material, for example, metal, in order to maintain the shape of the cooling member 500 .

[0168] 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 protruding parts 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 berm 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, or may have a height slightly lower than other parts of the fixing member 560. Considering the shapes of the protruding parts 524 and the berm 526, the end connecting parts 562 may be formed to have a step that is larger than that of the center connecting part 564.

[0169] 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, as 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, making it easier and more diverse to design the cooling member 500.

[0170] 22, the cooling hose 550 may be positioned to correspond to the opening 521 of the lower plate 520. The cooling hose 550 can inject internal cooling water toward the battery cell by melting or breaking when an internal fire occurs. 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 can be sprayed, ejected, or injected in the direction of gravity to extinguish the fire in the battery cell positioned below the cooling member 500. Meanwhile, in order to realize such an effect, the receiving part 548 to which the cooling hose 550 is attached must also be formed to correspond to the opening 521 of the lower plate 520.

[0171] Considering the structure of this embodiment, the fragile portion 600 of this embodiment 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 cooling hose 550 is formed.

[0172] The cooling hose 550 may be made of a material that melts or breaks at a predetermined temperature or pressure. The cooling hose 550 may be made of the same or similar material as the sealing member 529 of the previous embodiment.

[0173] Meanwhile, in order to realize the above-mentioned effect, it is also possible to configure the cooling tube 540 to be partially broken to inject cooling water without separately manufacturing the cooling hose 550. However, since the cooling tube 540 must be made of 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 made of a material that melts with heat or is easily broken by pressure. Therefore, it is preferable to configure the cooling hose 550, which can be easily broken by heat, separately from the cooling tube 540 as in this embodiment in order to improve the performance of the cooling member 500 as a whole.

[0174] Meanwhile, the battery pack included in the embodiment of the present invention may further include a Battery Management System (BMS) for managing the temperature and voltage of the battery and / or a cooling device.

[0175] The battery pack according to an embodiment of the present invention may be applied to various devices. For example, the device to which the battery pack is applied may be a means of transportation such as an electric bicycle, an electric car, a hybrid car, etc. However, the above-mentioned devices are not limited thereto, and the battery pack according to the present embodiment may be used in various devices other than the above-mentioned examples, which also fall within the scope of the present invention.

[0176] 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 belong to the scope of the present invention. [Explanation of symbols]

[0177] 1000: Battery pack 2000: Water Tank 3000: Cooling water supply pipe 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 Port 540: Cooling tube 550: Cooling hose 560: Fixing member 580: Cover film 590: Elastic member 600: Weakened part 700: Foam pad

Claims

1. A device having at least one battery pack attached thereto, The battery pack includes: a battery cell stack in which a plurality of battery cells are stacked; a pack frame that houses the battery cell stack; 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 located inside the device, At least one fragile portion that breaks or melts at a predetermined temperature or pressure or higher is formed on the lower plate of the cooling member, 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 device of claim 1 , wherein the cooling water in the water tank is supplied based on an electrical signal from a control unit that controls the operation of the water tank.

3. The device of claim 2 , wherein the cooling water in the water tank is supplied by a pump that operates based on the electrical signal.

4. the water tank is located above the battery pack; The device according to claim 1 , wherein the cooling water in the water tank is supplied to the cooling member by a pressure difference between the cooling member and the water tank.

5. The device of claim 4 , wherein the water tanks include a first water tank located at a front side of the device and a second water tank located at a rear side of the device.

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

8. The device of claim 7 , wherein the lower plate and the cooling tubes 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 device of claim 1 , wherein the first portion has a thickness value that is less than a thickness value of the second portion.

10. The device of claim 9 , wherein the first portion has a thickness value that 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; The device 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; a peak of the bent portion corresponds to the first portion, The device of claim 9 , wherein a valley of the bend corresponds to the second portion.

13. The device of claim 1 , wherein the top plate of the cooling member is integral with the pack frame.

Images