Cooling member and battery pack including same

Abstract

A cooling member according to one embodiment of the present invention is attached to a battery cell stack in which a plurality of battery cells are stacked. The cooling member includes an upper plate, a lower plate, a refrigerant contained in an internal space between the upper plate and the lower plate, and at least one of an upper structure supporting the upper plate and a lower structure supporting the lower plate, wherein the upper plate and the lower plate are made of a material that can melt or break when a thermal event occurs in the battery cell, and the upper structure and the lower structure are made of a material that maintains rigidity when a thermal event occurs in the battery cell.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0125134, filed on September 30, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a cooling member and a battery pack including the same, and more particularly to a cooling member provided with a reinforcing structure and a battery pack including the same. [Background technology]

[0003] In modern society, as the use of portable devices such as mobile phones, laptops, video cameras, and digital cameras has become commonplace, technological development in fields related to these mobile devices is accelerating. Furthermore, rechargeable secondary batteries are being used as the power source for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), and other vehicles as a way to address air pollution caused by existing gasoline-powered vehicles that use fossil fuels, and there is a growing need for the development of secondary batteries.

[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 able to be charged and discharged freely, having a low self-discharge rate, and having a high energy density.

[0005] Meanwhile, secondary batteries used in small devices typically use two to three battery cells, while secondary batteries used in medium- to large-sized devices such as automobiles typically use medium- to large-sized battery modules in which a number of battery cells are electrically connected. Since medium- to large-sized battery modules are preferably manufactured to be as small in size and weight as possible, prismatic batteries and pouch-shaped batteries, which can be stacked with a high degree of integration and have a low capacity-to-weight ratio, are primarily used as battery cells for medium- to large-sized battery modules.

[0006] Meanwhile, battery cells installed in a battery module can generate a large amount of heat during charging and discharging, and if their temperature rises above the appropriate temperature due to overcharging or other reasons, their performance can be reduced, and if the temperature rises excessively, there is a risk of explosion or fire. If a fire occurs inside a battery module, high-temperature heat, gas, or flames can be emitted outside the battery module. At this time, the heat, gas, sparks, or flames emitted from one battery module can be transferred to other adjacent battery modules at close intervals within the battery pack, causing continuous thermal runaway within the battery pack.

[0007] To prevent this thermal runaway phenomenon, recent attempts have been made to apply water-cooled cooling members or water-cooled heat dissipation members filled with a refrigerant. FIGS. 1 and 2 are perspective views of a conventional cooling member and a portion of a battery pack including the same, respectively. The cooling member 50 is provided to lower the internal temperature of a battery module or battery pack, including battery cells. The cooling member 50 may be a refrigerant or a water-cooled cooling member 50 into which a refrigerant is injected. By providing the cooling member 50 as a water-cooled type, the cooling efficiency of the cooling member 50 can be maintained uniformly, allowing the battery cells in the battery module or battery pack to be evenly cooled. Meanwhile, conventional cooling members 50 are made of a metal material such as aluminum to enable heat transfer. For example, the cooling member 50 is formed by joining two metal plates using a brazing process or the like.

[0008] However, because the cooling member 50 according to the prior art is made of a metal material, it is somewhat heavy, and the weight increases further when filled with a refrigerant (coolant). When a battery pack including such a cooling member 50 is installed in, for example, an automobile, the fuel efficiency of the automobile may be somewhat reduced. However, when the cooling member 50 is manufactured by injection molding of plastic or the like in order to reduce the weight, there is a problem that the rigidity of the cooling member is reduced.

[0009] Therefore, there is a need to develop a cooling member that is lighter in weight and less costly while increasing the rigidity of the heat dissipation member, and that is also easy to manufacture. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention provides a cooling member and a battery pack including the same that can inject a refrigerant at an appropriate time and place when a fire occurs inside a battery module or battery pack. More specifically, the present invention provides a cooling member and a battery pack including the same that can be easily manufactured while achieving weight reduction and cost reduction while increasing rigidity.

[0011] 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]

[0012] According to one embodiment of the present invention, a cooling member attached to a battery cell stack in which a plurality of battery cells are stacked includes an upper plate, a lower plate, a refrigerant contained in an internal space between the upper plate and the lower plate, and at least one of an upper structure supporting the upper plate and a lower structure supporting the lower plate, wherein the upper plate and the lower plate are made of a material that can melt or break when a thermal event occurs in the battery cell, and the upper structure and the lower structure are made of a material that maintains rigidity when a thermal event occurs in the battery cell.

[0013] The upper structure is attached to the outer surface of the upper plate, and the lower structure is attached to the outer surface of the lower plate.

[0014] A portion of the upper plate that does not contact the upper structure forms a weak portion, and a portion of the lower plate that does not contact the lower structure forms the weak portion, and the weak portion can melt or break when a thermal event occurs in the battery cell, thereby injecting the refrigerant into the battery cell.

[0015] At least one of the upper plate and the lower plate is made of plastic, and at least one of the upper structure and the lower structure is made of metal.

[0016] At least one of the upper plate and the lower plate is made of PP or PE, and at least one of the upper structure and the lower structure is made of stainless steel, aluminum, copper, or an alloy containing any of these.

[0017] The upper structure may include at least one of a vertical bar attached to the upper plate in the vertical direction and arranged parallel to the long side, a horizontal bar attached to the upper plate in the horizontal direction and arranged parallel to the short side, and a peripheral portion attached along the periphery of the upper plate.

[0018] The upper plate includes a groove in which the upper structure is mounted, and a low step is formed along the periphery of the upper plate, so that the structure and shape of the upper structure and the structure and shape of the groove and periphery of the upper plate can correspond to and engage with each other.

[0019] The grooves of the upper plate may include a first groove formed in a middle portion of the upper plate and arranged parallel to the long side of the upper plate, second grooves formed on both sides of the first groove and arranged parallel to the long side of the upper plate, and a third groove intersecting the first groove and the second groove and arranged parallel to the short side of the upper plate.

[0020] The vertical bars of the upper structure are fitted into the first groove and the second groove of the upper plate, and the horizontal bars of the upper structure are fitted into the third groove of the upper plate.

[0021] The cooling member may further include an inlet port and an outlet port on a first short side of the two short sides through which the refrigerant flows in and out, and one end of the first groove of the upper plate may be in contact with the first short side, and the other end of the first groove of the upper plate may be spaced a predetermined distance from a second short side of the cooling member so that the refrigerant can flow in a U-shape in the internal space of the cooling member.

[0022] Both ends of the second groove of the upper plate may be spaced apart from the first short side and the second short side by a predetermined distance so that the refrigerant can flow in the internal space of the cooling member.

[0023] The third groove of the upper plate and the horizontal bar of the upper structure are each formed in plural pieces.

[0024] The lower structure may include at least one of a vertical bar attached to the lower plate in the vertical direction and arranged parallel to the long side, a horizontal bar attached to the lower plate in the horizontal direction and arranged parallel to the short side, and a peripheral portion attached along the periphery of the lower plate.

[0025] The lower plate includes a groove in which the lower structure is mounted, and a low step is formed along the periphery of the lower plate, so that the structure and shape of the lower structure and the structure and shape of the groove and periphery of the lower plate can correspond to and engage with each other.

[0026] The grooves of the lower plate may include a fourth groove arranged parallel to a long side of the lower plate, and a fifth groove intersecting the fourth groove and arranged parallel to a short side of the lower plate.

[0027] The vertical bar of the lower structure is fitted into the fourth groove of the lower plate, and the horizontal bar of the lower structure is fitted into the fifth groove of the upper plate.

[0028] The fourth groove of the lower plate and the vertical bar of the lower structure each may be formed in plural, or the fifth groove of the lower plate and the horizontal bar of the lower structure each may be formed in plural.

[0029] The cooling member may further include a sealing pad disposed between the upper plate and the lower plate to prevent the coolant from leaking out of the cooling member.

[0030] The upper plate, the lower plate and the sealing pad can be riveted or bolted together.

[0031] The upper plate and the lower plate are integrally formed.

[0032] The cooling member may further include an inlet port through which the refrigerant flows into the cooling member, and an outlet port through which the refrigerant flows out of the cooling member.

[0033] The cooling member is attached to the upper surface of the battery cell stack.

[0034] A battery pack according to another embodiment of the present invention includes the cooling member described above. [Effects of the Invention]

[0035] When a fire occurs inside a battery module or a battery pack, the cooling member according to an embodiment of the present invention can quickly extinguish the fire inside the battery module or the battery pack by opening a portion of the battery module or the battery pack and injecting a refrigerant at an appropriate time and place, thereby preventing a continuous thermal runaway phenomenon.

[0036] Furthermore, the cooling member according to the embodiment of the present invention has the advantages of being lighter in weight, reducing costs, and being easier to manufacture, while still providing increased rigidity.

[0037] 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 explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a perspective view showing a cooling member according to the prior art and a part of a battery pack including the cooling member. [Figure 2] FIG. 1 is a perspective view showing a cooling member according to the prior art and a part of a battery pack including the cooling member. [Figure 3] 1 is an exploded perspective view showing a battery pack according to an embodiment of the present invention; [Figure 4] FIG. 4 is a perspective view of a battery module included in the battery pack shown in FIG. 3. [Figure 5] 4 is a perspective view of a cooling member included in the battery pack shown in FIG. 3 and a battery module disposed below the cooling member. [Figure 6] FIG. 6 is a partially enlarged view of FIG. 5. [Figure 7] FIG. 6 is an exploded perspective view of the cooling member of FIG. 5. [Figure 8] FIG. 6 is a perspective view of the top plate of the cooling member of FIG. 5. [Figure 9] FIG. 6 is a perspective view of a lower plate of the cooling member of FIG. 5. [Figure 10] FIG. 6 is a perspective view of an upper structure of the cooling member of FIG. 5. [Figure 11] FIG. 6 is a perspective view of a lower structure of the cooling member of FIG. 5. [Figure 12] FIG. 6 is a perspective view of a sealing pad of the cooling member of FIG. 5. [Figure 13] FIG. 10 is a diagram showing a method for injecting refrigerant into a cooling member when a thermal event occurs in a battery cell. [Figure 14] FIG. 2 is an enlarged view of a portion of the flow of the refrigerant. [Figure 15] 6A to 6C are diagrams showing the process of assembling the cooling member of FIG. 5. [Figure 16] 6A to 6C are diagrams showing the process of assembling the cooling member of FIG. 5. [Figure 17] 6A to 6C are diagrams showing the process of assembling the cooling member of FIG. 5. [Figure 18] 6A to 6C are diagrams showing the process of assembling the cooling member of FIG. 5. [Figure 19] 6A to 6C are diagrams showing the process of assembling the cooling member of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0039]

[0023] Hereinafter, 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 can be realized in various different forms other than those described below, and the scope of the present invention is not limited to the embodiments described herein.

[0040] In order to clearly explain the present invention, parts that are not necessary for the explanation will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0041] Furthermore, the size and thickness of each component shown in the drawings are arbitrarily enlarged or reduced for the sake of convenience, and it is obvious that the content of the present invention is 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 sake of convenience.

[0042] Furthermore, when a layer, film, region, plate, or other portion is described as being "above" another portion, this should be interpreted as including not only the case where the corresponding layer, film, region, plate, or other portion is "directly above" the other portion, but also the case where there is another portion between them. Conversely, when a corresponding layer, film, region, plate, or other portion is described as being "directly above" another portion, it can mean that there is no other portion between them. Furthermore, being "above" a reference portion means being located above or below the reference portion, and does not necessarily mean being "above" in the opposite direction of gravity. Meanwhile, the description of being "above" another portion, as well as the description of being "below" another portion, can be understood with reference to the above content.

[0043] Furthermore, since the upper and lower surfaces of a particular component may be determined differently depending on the reference direction, throughout this specification, "upper surface" or "lower surface" is defined to mean the two surfaces of the component that face each other along the z-axis.

[0044] Furthermore, throughout the specification, when a part "comprises" a certain element, this means that it can further include other elements, but not excluding other elements, unless specifically stated to the contrary.

[0045] Furthermore, throughout the specification, "on a plane" means when the part is viewed from above, and "on a cross section" means when the part is cut vertically and viewed from the side.

[0046] A battery pack according to an embodiment of the present invention will now be described.

[0047] FIG. 3 is an exploded perspective view of a battery pack according to an embodiment of the present invention. FIG. 4 is a perspective view of a battery module included in the battery pack according to FIG. 3. Referring to FIG. 3, a battery pack 1000 according to an embodiment of the present invention may include at least one battery module 100, a pack frame 200 that houses the battery module 100, a resin layer 300 formed on the inner surface of the pack frame 200, an end plate 400 that closes the open surface of the pack frame 200, a cooling member 500 disposed between the pack frame 200 and the battery cell stack 120, and cooling fins 600 that contact the battery cells 110 to release heat from the battery cells 110. However, the components included in the battery pack 1000 are not limited thereto, and the battery pack 1000 may be provided without some of the above-mentioned components or with other unmentioned components added, depending on the design.

[0048] 3 and 4, the battery module 100 provided in this embodiment may have a module-less structure in which a module frame is omitted.

[0049] Typically, conventional battery packs have a double-assembly structure in which a battery module is formed by assembling a battery cell stack and various components connected thereto, and multiple battery modules are then housed in the battery pack. Since the battery module includes a module frame that forms its outer surface, 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 if some battery cells are defective. Furthermore, if a cooling element is located outside the battery module, the heat transfer path between the battery cells and the cooling element becomes somewhat complicated.

[0050] Therefore, the battery module 100 of this embodiment is provided in the form of a "cell block" that omits the module frame, and the battery cell stack 120 included in the cell block is directly coupled to the pack frame 200 of the battery pack 1000. This simplifies the structure of the battery pack 1000, provides advantages in terms of manufacturing cost and manufacturing process, and achieves the effect of reducing the weight of the battery pack.

[0051] Hereinafter, a battery module 100 without a module frame will be referred to as a "cell block" to distinguish it from a battery module with a module frame. However, the battery module 100 is a general term that refers to a battery cell stack 120 that has been segmented into predetermined units for modularization, regardless of whether or not a module frame is present, and the battery module 100 should be interpreted as including all conventional battery modules and cell blocks that have a module frame.

[0052] Referring to FIG. 4 , the battery module 100 of this embodiment 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 bus bar frames 150 that cover the front and rear of the battery cell stack 120.

[0053] Meanwhile, while FIG. 4 shows a battery module 100 provided in the form of a cell block, the content of this drawing does not exclude the application of a sealed structure battery module 100 having a module frame to the battery pack 1000 of this embodiment.

[0054] Each battery cell 110 may include an electrode assembly, a cell case, and electrode leads protruding from the electrode assembly. The battery cells 110 may be provided in a pouch or prismatic shape to maximize the number of cells stacked per unit area. For example, a pouch-type battery cell 110 may be manufactured by placing an electrode assembly including a positive electrode, a negative electrode, and a separator in a cell case made of a laminate sheet and then heat-sealing the sealing portion of the cell case. While FIGS. 3 and 4 show the positive and negative electrode leads of the battery cell 110 protruding in opposite directions, this is not necessarily the case; the electrode leads of the battery cell 110 may also protrude in the same direction.

[0055] 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" may be interpreted as including both + / - directions) as shown in Figures 3 and 4.

[0056] Meanwhile, by arranging the battery cells 110 in one direction, the electrode leads of the battery cells 110 can be located on one side of the battery cell stack 120, or on one side and the other side opposite the one side. In this way, the side of the battery cell stack 120 on which the electrode leads are located is referred to as the front side or rear side of the battery cell stack 120, and in Figures 3 and 4, the front side and rear side of the battery cell stack 120 are shown as two sides facing each other on the x-axis.

[0057] 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 in Figures 3 and 4, the side surfaces of the battery cell stack 120 are shown as two surfaces facing each other on the y-axis.

[0058] The side plates 130 are provided to maintain the overall shape of the battery cell stack 120. The side plates 130 are plate-shaped members that can supplement the rigidity of the cell blocks in place of the module frame. The side plates 130 are arranged at both ends of the battery cell stack 120 in the stacking direction and can come into contact with the outermost battery cells 110 on both sides of the battery cell stack 120.

[0059] The side plate 130 can be made of various materials and provided by various manufacturing methods. For example, the side plate 130 may be made of a plastic material manufactured by injection molding. For another example, the side plate 130 may be made of a leaf spring material. For yet another example, the side plate 130 may be made of an elastic material so that its shape can be partially deformed in response to a volume change of the battery cell stack 120 due to swelling.

[0060] The holding straps 140 are used to fix the position and shape of the side plates 130 on both ends of the battery cell stack 120. The holding straps 140 may be members having a length and width. Specifically, the battery cell stack 120 is positioned between the two side plates 130 that contact the outermost battery cells 110, and the holding straps 140 may cross the battery cell stack 120 to connect the two side plates 130. In this way, the holding straps 140 prevent the distance between the two side plates 130 from increasing beyond a certain range, thereby maintaining the overall shape of the cell block within a certain range.

[0061] The holding strap 140 may have hooks at both longitudinal ends for stable connection with the side plate 130. The hooks are formed by bending both longitudinal ends of the holding strap 140. Meanwhile, locking grooves are formed in the side plate 130 at positions corresponding to the hooks, and the connection between the hooks and the locking grooves allows the holding strap 140 and the side plate 130 to be stably connected.

[0062] The holding straps 140 may be made of various materials or manufactured by various methods. For example, the holding straps 140 may be made of an elastic material, which allows the volumetric change of the battery cell stack 120 due to swelling to be within a certain range.

[0063] Meanwhile, the holding straps 140, which are used to secure the relative positions between the side plates 130 and the battery cell stack 120, may be provided in a form different from that shown in the drawing, as long as their purpose as a "securing member" is achieved. For example, the securing member may be provided in the form of a long bolt that can traverse between the two side plates 130. The side plates 130 may have grooves into which the long bolts can be inserted, and the long bolts can secure the relative positions of the two side plates 130 by simultaneously connecting them through the grooves. The long bolts are provided on the periphery of the side plates 130, preferably near the apexes of the side plates 130. Depending on the design, the holding straps 140 may be replaced with the long bolts described above, or both the holding straps 140 and the long bolts may be provided on the cell block.

[0064] The bus bar frame 150 is positioned on one side of the battery cell stack 120 to cover that side and also to guide the connection of the battery cell stack 120 to an external device. The bus bar frame 150 may be positioned on the front or rear side of the battery cell stack 120. Two bus bar frames 150 are provided, one on the front side and one on the rear side of the battery cell stack 120. Bus bars are attached to the bus bar frames 150, and electrode leads of the battery cell stack 120 are connected to the bus bars, thereby enabling the battery cell stack 120 to be electrically connected to an external device.

[0065] The bus bar frame 150 may include an electrically insulating material. The bus bar frame 150 may limit contact between the bus bar and other parts of the battery cell 110 other than the part connected to the electrode lead, thereby preventing an electrical short circuit from occurring.

[0066] The pack frame 200 is intended to protect the battery modules 100 and the electrical components connected thereto from external physical impacts. The pack frame 200 can accommodate the battery modules 100 and the electrical components connected thereto in the 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 is defined by the internal surface.

[0067] A plurality of battery modules 100 may be accommodated within the pack frame 200. A plurality of battery modules 100 is referred to as a "module assembly." The module assembly is arranged in rows and columns within the pack frame 200. Here, a "row" may refer to a set of battery modules 100 arranged in one direction, and a "column" may refer to a set of battery modules 100 arranged in a direction perpendicular to the one direction. For example, as shown in FIG. 3, the battery modules 100 may be arranged along the stacking direction of the battery cell stack to form a module assembly in one row or column.

[0068] The pack frame 200 is provided in a hollow shape that is open in one direction. For example, as shown in Fig. 3, a plurality of battery modules 100 are sequentially positioned in the stacking direction of the battery cells 110, and the pack frame 200 may have a hollow shape that is open in the stacking direction.

[0069] The structure of the pack frame 200 may vary. For example, as shown in Fig. 3, the pack frame 200 may include a lower frame 210 and an upper frame 220. Here, the lower frame 210 is provided in a plate shape, and the upper frame 220 is provided in a U-shape. At least one battery module 100 is disposed on the plate-shaped lower frame 210, and the U-shaped upper frame 220 is provided to surround the top surface of the module assembly and two sides on the x-axis.

[0070] The pack frame 200 may include a portion with high thermal conductivity to quickly release heat generated from the internal space to the outside. For example, at least a portion of the pack frame 200 may be made of a metal with high thermal conductivity, such as aluminum, gold, silver, copper, platinum, or an alloy containing these. In addition, the pack frame 200 may be partially electrically insulating, and an insulating film may be provided or an insulating coating may be applied to a location 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.

[0071] A resin layer 300 is provided between the battery module 100 and the inner surface of the pack frame 200. The resin layer 300 is provided between the bottom surface of the battery module 100 and the lower frame 210. The resin layer 300 is provided between the top surface of the battery module 100 and the upper frame 220. Specifically, the resin layer 300 is provided between a cooling member 500 (described later) and the upper frame 220.

[0072] 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 limited to this, and the resin layer 300 may also be a member provided in a plate shape.

[0073] The resin layer 300 may be made of various materials, and its functions vary depending on the material. For example, the resin layer 300 may be made of an insulating material to prevent electron transfer between the battery module 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 transfers heat generated from the battery cells 110 to the pack frame 200, thereby allowing the heat to be released / transferred to the outside. As yet another example, the resin layer 300 may include an adhesive material, thereby fixing the battery module 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.

[0074] The end plates 400 serve to protect the battery modules 100 and the 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 can be joined to a corresponding corner of the pack frame 200 by welding or other methods. Two end plates 400 are provided to seal the two open sides of the pack frame 200, and are made of a metal material having a predetermined strength.

[0075] The end plate 400 has an opening 410 for exposing an inlet / outlet port 530 of the cooling member 500 described later, and is fitted with a connector 420 for LV (Low voltage) connection or HV (High voltage) connection with an external device.

[0076] The cooling member 500 cools the inside of the battery pack 1000 by dissipating heat generated from the battery cells 110. Considering that high-temperature air or gases released when the battery cells 110 ignite move primarily in the direction opposite to gravity, it is preferable that the cooling member 500 be located above the battery cells 110 as shown in Fig. 3. However, this is not necessarily the case, and the cooling member 500 may also be located below the battery cells 110 for various design reasons.

[0077] The cooling member 500 may be a water-cooled cooling member 500 into which a refrigerant is injected, for example. In this case, any refrigerant may be used in the cooling member 500 as long as it can dissipate heat from the battery cells 110 by moving along a flow path inside the cooling member 500.

[0078] FIG. 5 is a perspective view of a cooling element included in the battery pack according to FIG. 3 and a battery module disposed below the cooling element. FIG. 6 is a partially enlarged view of FIG. 5. FIG. 7 is an exploded perspective view of the cooling element of FIG. 5. FIGS. 8 and 9 are perspective views of the upper and lower plates of the cooling element of FIG. 5, respectively. FIGS. 10 and 11 are perspective views of the upper and lower structures of the cooling element of FIG. 5, respectively. FIG. 12 is a perspective view of the sealing pad of the cooling element of FIG. 5. FIG. 13 shows a method for injecting refrigerant into the cooling element when a thermal event occurs in a battery cell. FIG. 14 shows an enlarged view of a portion of the refrigerant flow.

[0079] 5 to 7, and more specifically, FIG. 7, the cooling member 500 may include an upper plate 510, a lower plate 520, and an inlet / outlet port 530. The cooling member 500 is formed by combining the upper plate 510 and the lower plate 520. A space is formed between the combined upper plate 510 and lower plate 520, and a refrigerant is injected into the space through the inlet / outlet port 530. The refrigerant is supplied through the inlet port 530 and discharged to the outlet port 530. The cooling member 500 further includes an upper structure 540 that supports the upper plate 510 and a lower structure 550 that supports the lower plate 520.

[0080] 8 and 9, grooves 511 and 521 are formed on the outer surface of the upper plate 510 and the outer surface of the lower plate 520, respectively. Here, the outer surface refers to the outer surface of the cooling member 500 when the upper plate 510 and the lower plate 520 are combined to form the cooling member 500.

[0081] An upper structure 540 shown in Fig. 10 and a lower structure 550 shown in Fig. 11 are attached to grooves 511 of upper plate 510 and grooves 521 of lower plate 520, respectively, and the flow of the refrigerant (cooling water) is determined by the structure of grooves 511 and 521. Fig. 5 shows, as an example, that the flow of the refrigerant (cooling water) is formed in a U-shape by grooves 511 and 521 formed in cooling member 500.

[0082] For example, referring to groove 511 of upper plate 510 in Fig. 7, groove 511 includes a first groove 511a located in the middle in the vertical direction (in the y-axis direction) and two second grooves 511b located on both sides of first groove 511a. Groove 511 also includes one or more third grooves 511c in the horizontal direction perpendicular to the vertical direction. Third groove 511c intersects with first groove 511a and second groove 511b.

[0083] The flow of the refrigerant (coolant) is determined by the structure of the first groove 511a. More specifically, the first groove 511a extends vertically from a first short side of the cooling member 500, on which the inlet / outlet port 530 is provided, to a midpoint between the inlet port 530 and the outlet port 530 of the cooling member 500. At this time, the first groove 511a extends only to a point spaced a predetermined distance from a second short side, which is the remaining short side of the two short sides of the cooling member 500. This forms a point where the refrigerant makes a detour (U-turn) (see FIG. 14).

[0084] In other words, one end of the first groove 511a contacts the first short side where the inlet / outlet port 530 is provided, and the other end of the first groove 511a is spaced a predetermined distance from the second short side. As a result, the refrigerant flows into the inlet port 530, passes through the space between the end of the first groove 511a and the second short side, and flows out of the outlet port 530. As a result, the flow of the refrigerant (cooling water) in the cooling member 500 is formed in a U-shape.

[0085] In addition, the bottom of the first groove 511a can contact the lower plate 520. As a result, the inside of the cooling member 500 is roughly divided into two sections: a section where the refrigerant flows into the inlet port 530 and to the detour point, and a section where the refrigerant flows from the detour point to the outlet port 530.

[0086] Of course, as will be described later, an upper structure 540 is attached to the first groove 511a to complement the rigidity of the cooling member 500.

[0087] The second grooves 511b are provided to supplement the rigidity of the cooling member 500 in the vertical direction. The two second grooves 511b are arranged on both sides of the first groove 511a in the vertical direction of the cooling member 500, and both ends of the second grooves 511b are spaced a predetermined distance from the two short sides of the cooling member 500, respectively. This prevents the U-shaped flow of refrigerant (coolant) inside the cooling member 500 from being obstructed (see FIG. 14). On the other hand, as long as the depth of the second grooves 511b is somewhat shallow and does not obstruct the flow of refrigerant in the internal space of the cooling member 500, i.e., as long as the second grooves 511b do not come into contact with the sealing pad 560 and / or the lower plate 520, which will be described later, the both ends of the second grooves 511b may come into contact with the two short sides of the cooling member 500.

[0088] The third groove 511c is also provided to improve the rigidity of the cooling member 500. One or more third grooves 511c are provided in the lateral direction (x-axis direction) of the cooling member 500. In the embodiment of FIGS. 5 to 7, a plurality of third grooves 511c are shown. The third grooves 511c are provided to complement the rigidity of the cooling member 500 in the lateral direction. Both ends of the third groove 511c contact the two long sides of the cooling member 500, respectively. At this time, the depth of the third groove 511c is shallower than the depth of the first groove 511a so that the flow of the U-shaped refrigerant is not obstructed by the third groove 511c.

[0089] Furthermore, the peripheral edge 512 of the upper plate 510 has a step with respect to the cross section of the upper plate 510 in the height direction (with respect to the z-axis). That is, the height of the peripheral edge 512 along the periphery of the upper plate 510 is lower than the height of the portion of the upper plate 510 through which the refrigerant flows. As will be described later, the height of the peripheral edge 522 along the periphery of the lower plate 520 is lower than the height of the portion of the lower plate 520 through which the refrigerant flows. As a result, the peripheral edge 512 of the upper plate 510 and the peripheral edge 522 of the lower plate 520 abut and are coupled to each other, and a channel through which the refrigerant flows is formed in the internal space between the upper plate 510 and the lower plate 520.

[0090] 10, the upper structure 540 is mounted in a groove 511 formed on the outer surface of the upper plate 510. In this case, the outer surface of the upper plate 510 to which the upper structure 540 is coupled may be substantially flat.

[0091] The upper structure 540 includes at least one of vertical bars 541, 542 attached to the upper plate 510 in the vertical direction and arranged parallel to the long side, a horizontal bar 543 attached to the upper plate 510 in the horizontal direction and arranged parallel to the short side, and a peripheral portion 544 attached to the peripheral portion 512 of the upper plate 510.

[0092] Furthermore, the shape and structure of the upper structure 540 may entirely or partially match the shape and structure of the groove 511 and / or the shape and structure of the peripheral edge 512. To further explain, for example, the upper structure 540 includes a portion that matches the first groove 511a and at least one of the two second grooves 511b, and / or a portion that matches the third groove 511c, and / or a portion that matches the peripheral edge 512 of the upper plate 510.

[0093] In the embodiment of Figure 10, for example, the upper structure 540 includes a first vertical bar 541 attached to the first groove 511a in the middle part of the upper plate 510, a second vertical bar 542 attached to each of the two second grooves 511b of the upper plate 510, a horizontal bar 543 attached to the third groove 511c of the upper plate 510, and a peripheral portion 544 attached to the peripheral portion 512 of the upper plate 510.

[0094] The first vertical bar 541 and the second vertical bar 542 are arranged parallel to the two long sides of the cooling member 500 along the vertical direction (y-axis direction) of the cooling member 500. One end of the first vertical bar 541 contacts the first short side of the two short sides of the peripheral edge 544, where the inlet / outlet port 530 is provided, and the other end of the first vertical bar 541 is spaced a predetermined distance from the second short side. Both ends of the second vertical bar 542 are spaced a predetermined distance from the two short sides of the peripheral edge 544. The horizontal bar 543 connects the two short sides of the cooling member 500 to each other along the horizontal direction (x-axis direction) of the cooling member 500.

[0095] Meanwhile, the cooling member 500 may be a cooling tank type that does not have the inlet / outlet ports 530. The first vertical bar 541 and the second vertical bar 542 may have a shape in which both ends thereof extend to the peripheral edge 544 and contact each other. In other words, they may have the same shape and structure as the lower structure 550 described below. The present invention is not limited to the above and various modifications and variations are possible.

[0096] The grooves 521 of the lower plate 520 of FIG. 9 may have a generally quadrangular (e.g., rectangular or square) lattice structure, slightly different from the grooves 511 of the upper plate 510 of FIG. 8. That is, one or more fourth grooves 521a are formed along the vertical direction (y-axis direction) of the cooling member 500, connecting the two long sides of the cooling member 500 to each other. That is, both ends of the fourth groove 521a are in contact with the two long sides, respectively. In addition, one or more fifth grooves 521b are formed along the horizontal direction (x-axis direction) of the cooling member 500, connecting the two short sides of the cooling member 500 to each other. That is, both ends of the fifth groove 521b are in contact with the two short sides, respectively.

[0097] Referring to FIG. 11, the lower structure 550 is mounted in a groove 521 formed on the outer surface of the lower plate 520, and the shape and structure of the lower structure 550 may entirely or partially match the shape and structure of the groove 521 and / or the shape and structure of the peripheral portion 522.

[0098] The lower structure 550 includes at least one of a vertical bar 551 attached to the lower plate 520 in the vertical direction and arranged parallel to the long side, a horizontal bar 552 attached to the lower plate 520 in the horizontal direction and arranged parallel to the short side, and a peripheral portion 553 attached to the peripheral portion 522 of the lower plate 520.

[0099] 11, for example, the lower structure 550 includes a plurality of vertical bars 551 respectively mounted in the plurality of fourth grooves 521a of the lower plate 520, a plurality of horizontal bars 552 respectively mounted in the plurality of fifth grooves 521b of the lower plate 520, and a peripheral portion 553 mounted on the peripheral portion 522 of the lower plate 520. The vertical bars 551 connect the two long sides of the cooling member 500 to each other along the vertical direction (y-axis direction) of the cooling member 500. The horizontal bars 552 connect the two short sides of the cooling member 500 to each other along the horizontal direction (x-axis direction) of the cooling member 500.

[0100] 9 and 13, the area surrounded by the fourth groove 521a and the fifth groove 521b forms a fragile portion 523, which will be described later. A rigid lower structure 550 is attached to the groove 521 of the lower plate 520. However, the fragile portion 523 surrounded by the fourth groove 521a and the fifth groove 521b exists only in the lower plate 520, which is injection-molded from a material such as plastic. Therefore, when a thermal event occurs in a battery cell in contact with the lower part of the cooling member 500, the fragile portion 523, which is the portion where the rigid lower structure 550 is not attached, melts, and the coolant of the cooling member 500 is injected into the battery module 100.

[0101] 7 and 12, the sealing pad 560 is disposed between the upper plate 510 and the lower plate 520. When a refrigerant flows in the internal space between the upper plate 510 and the lower plate 520, the sealing pad 560 prevents the refrigerant from leaking out of the cooling member 500.

[0102] 12 , the first vertical bar 561 of the sealing pad 560 matches the structure and shape of the first groove 511a of the upper plate 510 and is disposed between the bottom of the first groove 511a of the upper plate 510 and the top of the fourth groove 521a of the lower plate 520. The two second vertical bars 562 of the sealing pad 560 match the structure and shape of the two second grooves 511b of the upper plate 510 and are disposed between the bottom of the second groove 511b of the upper plate 510 and the top of the fourth groove 521a of the lower plate 520. The peripheral edge 563 of the sealing pad 560 is disposed between the peripheral edge 512 of the upper plate 510 and the peripheral edge 522 of the lower plate 520.

[0103] Meanwhile, the upper plate 510 and the lower plate 520 are made of a material that is resistant to coolant and does not have a high heat resistance so that they can melt when a thermal event occurs in the battery cells, such as a plastic material such as PP or PE. The upper plate 510 and the lower plate 520 are manufactured by injection molding and can melt / break when a thermal event occurs in the battery cells. The upper structure 540 and the lower structure 550 are made of a rigid metal material such as stainless steel, aluminum, copper, or an alloy containing these. The upper structure 540 and the lower structure 550 enable the cooling member 500 to maintain its overall structure and shape. The sealing pad 560 is made of an elastic material such as a silicone-based foam pad, an acrylic-based foam pad, or a urethane-based foam pad.

[0104] 5 to 13 are merely examples, and the present invention is not limited thereto. In other words, various modifications and changes can be made to the structure, shape, and arrangement of cooling member 500 and each of the components of cooling member 500 depending on the environment in which the present invention is realized.

[0105] For example, the upper plate 510 and / or the lower plate 520 may not be provided with the grooves described above, and only the upper structure 540 and / or the lower structure 550 may surround the flat upper plate 510 and / or the lower plate 520 or may be attached to the upper plate 510 and / or the lower plate 520. Alternatively, the upper structure 540 and / or the lower structure 550 may be attached to the inner surface of the upper plate 510 and / or the lower plate 520, and various other modifications and variations are possible.

[0106] 15 to 19 show the process of assembling the components of the cooling member 500 of FIG. 5 to manufacture the cooling member 500. First, a lower plate 520 is provided (FIG. 15). Next, a sealing pad 560 is placed on the inner surface (upper surface) of the lower plate 520 (FIG. 16). Next, an upper plate 510 is placed on the sealing pad 560 (FIG. 17). Here, for the detailed arrangement of components between the lower plate 520, the sealing pad 560, and the upper plate 510, please refer to the description above with reference to FIGS. 7 to 12.

[0107] Next, the lower structure 550 is mounted on the outer surface of the lower plate 520 (FIG. 18). The assembly in which the lower plate 520, sealing pad 560, and upper plate 510 are connected as described above in FIGS. 15 to 17 may be inverted and mounted on the lower structure 550, and then the assembly together with the lower structure 550 may be inverted again. Alternatively, the assembly in which the lower plate 520, sealing pad 560, and upper plate 510 are connected may be mounted directly on the lower structure 550. Alternatively, after the lower plate 520 is mounted on the lower structure 550 in FIG. 15, the sealing pad 560 and upper plate 510 may be mounted, respectively, in the manner described in FIGS. 16 and 17.

[0108] Finally, the upper structure 540 is attached to the outer surface (upper surface) of the upper plate 510, and the lower structure 550, lower plate 520, sealing pad 560, upper plate 510, and upper structure 540 are fastened together using rivets or bolts to complete the manufacturing of the cooling member 500.

[0109] Meanwhile, the present invention is not limited to the above, and various modifications and variations are possible, such as in some cases not including the sealing pad 560, the upper plate 510 and the lower plate 520 being integrally injection molded, and the upper structure 540 and the lower structure 550 being attached to the outer surfaces of the upper plate 510 and the lower plate 520, respectively.

[0110] Meanwhile, although the above description has been given on the basis that the cooling member 500 is provided outside the battery module 100, this is not necessarily limited thereto, and the cooling member 500 may also be disposed inside the battery module 100. If the cooling member 500 is disposed inside the battery module 100, heat transfer between the cooling member 500 and the battery cells 110 can be easily achieved even if the battery module 100 has a closed structure having a module frame.

[0111] As described above, when the cooling member 500 is provided in the battery pack 1000 or the battery module 100, heat generated from the battery cells 110 is absorbed and released by the cooling member 500. However, since it is nearly impossible to design the cooling member 500 and the battery cells 110, which are assembled after being manufactured, so that they are in perfect contact within the battery pack 1000 or the battery module 100, a separation space usually occurs between the cooling member 500 and the battery cells 110. As described above, an air gap or air pocket may be formed in the separation space generated between the cooling member 500 and the battery cells 110, which may inhibit smooth heat transfer from the battery cells 110 to the cooling member 500, resulting in a slight decrease in the cooling efficiency of the cooling member 500.

[0112] In order to overcome the reduction in cooling efficiency due to air pockets, a method of forming a heat transfer path by filling the above-mentioned separation space with a thermal interface material (TIM) has been proposed. However, there are problems in that the overall manufacturing cost of the battery pack 1000 increases due to the cost of the thermal interface material, and the manufacturing time of the battery pack 1000 increases due to the additional process. Therefore, the battery module 100 or the battery pack 1000 of this embodiment is provided with cooling fins 600 to minimize the reduction in cooling efficiency due to the air gap.

[0113] Meanwhile, although not specifically mentioned above, a battery pack according to an embodiment of the present invention may additionally include a battery management system (BMS) that manages the temperature, voltage, etc. of the battery and / or a cooling device.

[0114] Furthermore, 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 vehicle, a hybrid vehicle, 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, and this also falls within the scope of the present invention.

[0115] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0116] 100: Battery module 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 511, 521: Groove 512, 522: Periphery 523: Weak part 530: Inlet / Outlet Port 540:Superstructure 550: Substructure 560: Sealing pad 541, 542, 551, 561, 562: Vertical bars 543, 552: Horizontal bar 544, 553, 563: Periphery 600: Cooling fin

Claims

1. A cooling member attached to a battery cell stack in which a plurality of battery cells are stacked, an upper plate, a lower plate, and a refrigerant contained in an internal space between the upper plate and the lower plate; at least one of an upper structure supporting the upper plate and a lower structure supporting the lower plate, the upper plate and the lower plate are made of a material that can melt or break when a thermal event occurs in the battery cell; The upper structure and the lower structure are cooling members made of a material that maintains rigidity when a thermal event occurs in the battery cell.

2. the upper structure is attached to an outer surface of the upper plate; The cooling element of claim 1 , wherein the substructure is attached to an exterior surface of the lower plate.

3. a portion of the upper plate that does not contact the upper structure forms a weak portion; a portion of the lower plate that does not come into contact with the lower structure forms the weak portion; The cooling member according to claim 1 or 2, wherein the fragile portion melts or breaks when a thermal event occurs in the battery cell, thereby allowing the coolant to be injected into the battery cell.

4. At least one of the upper plate and the lower plate is made of plastic, 3. The cooling member according to claim 1, wherein at least one of the upper structure and the lower structure is made of a metal material.

5. At least one of the upper plate and the lower plate is made of PP or PE, The cooling member according to claim 4 , wherein at least one of the upper structure and the lower structure is made of stainless steel, aluminum, copper, or an alloy containing any of these.

6. The superstructure is a vertical bar attached to the upper plate in the vertical direction and arranged parallel to the long side; a horizontal bar attached to the upper plate in the horizontal direction and arranged parallel to the short side; and a peripheral portion attached along the periphery of the upper plate; The cooling member according to claim 1 or 2, comprising at least one of the following:

7. the upper plate includes a groove in which the upper structure is mounted; A low step is formed along the periphery of the upper plate, The cooling element of claim 6 , wherein the configuration and shape of the upper structure and the configuration and shape of the groove and the periphery of the top plate correspond and mate with each other.

8. The groove in the upper plate is a first groove formed in a middle portion of the upper plate and arranged parallel to a long side of the upper plate; second grooves formed on both sides of the first groove and arranged parallel to the long sides of the upper plate; The cooling member according to claim 7 , further comprising a third groove intersecting the first groove and the second groove and disposed parallel to a short side of the upper plate.

9. the vertical bar of the upper structure is fitted into the first groove and the second groove of the upper plate; The cooling member of claim 8 , wherein the cross bar of the upper structure is mounted in the third groove of the top plate.

10. The cooling member further includes an inlet port and an outlet port on a first short side of the two short sides through which the refrigerant flows in and out, One end of the first groove of the upper plate contacts the first short side, 9. The cooling member of claim 8, wherein the other end of the first groove of the upper plate is spaced a predetermined distance from a second short side of the cooling member so that the refrigerant can flow in a U-shape in the internal space of the cooling member.

11. The cooling member of claim 10 , wherein both ends of the second groove of the upper plate are spaced a predetermined distance from the first short side and the second short side, respectively, so that the refrigerant can flow in the internal space of the cooling member.

12. The cooling member according to claim 8 , wherein the third groove of the upper plate and the horizontal bar of the upper structure are each formed in a plurality of pieces.

13. The substructure is a vertical bar attached to the lower plate in the vertical direction and arranged parallel to the long side; a horizontal bar attached to the lower plate in the horizontal direction and arranged parallel to the short side; and a peripheral portion attached along the periphery of the lower plate; The cooling member according to claim 1 or 2, comprising at least one of the following:

14. the lower plate includes a groove in which the lower structure is mounted; A low step is formed along the periphery of the lower plate, The cooling element of claim 13 , wherein the configuration and shape of the lower structure and the configuration and shape of the groove and the periphery of the lower plate correspond and mate with each other.

15. The groove of the lower plate is a fourth groove disposed parallel to the long side of the lower plate; The cooling member according to claim 14 , further comprising a fifth groove intersecting the fourth groove and disposed parallel to a short side of the lower plate.

16. The vertical bar of the lower structure is fitted into the fourth groove of the lower plate, The cooling member of claim 15 , wherein the cross bar of the lower structure is mounted in the fifth groove of the upper plate.

17. The fourth groove of the lower plate and the vertical bar of the lower structure are each composed of a plurality of pieces, or The cooling member according to claim 16 , wherein the fifth groove of the lower plate and the horizontal bar of the lower structure are each formed in a plurality of pieces.

18. The cooling member according to claim 1 or 2, further comprising a sealing pad disposed between the upper plate and the lower plate to prevent the coolant from leaking outside the cooling member.

19. The cooling element of claim 18 , wherein the top plate, the bottom plate, and the sealing pad are riveted or bolted together.

20. The cooling member according to claim 1 or 2, wherein the upper plate and the lower plate are integrally formed.

21. an inlet port through which the refrigerant flows into the cooling member; The cooling member according to claim 1 or 2, further comprising an outlet port through which the coolant flows into the interior of the cooling member.

22. The cooling member according to claim 1 or 2, wherein the cooling member is attached to an upper surface of the battery cell stack.

23. A battery pack comprising the cooling member according to claim 1 or 2.

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