Cooling fin, battery module, battery pack and device including same

Abstract

A battery pack according to one embodiment of the present invention includes a battery module including a battery cell stack in which a plurality of battery cells are stacked, a pack frame that houses the battery module, and a heat sink located between the battery cell stack and the pack frame, and a cooling fin is disposed between two adjacent battery cells, and the cooling fin includes a main body portion that contacts the battery cells and an extension portion that extends to the upper side (z-axis) of the battery cell stack and is located adjacent to the heat sink, and the extension portion has a bent portion formed by bending in a direction different from the upper side (z-axis).

Description

[Technical field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0086817 filed on July 2, 2021, and Korean Patent Application No. 10-2021-0172790 filed on December 6, 2021, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a cooling fin, a battery module, a battery pack, and a device including the same, and more specifically to a cooling fin, a battery module, a battery pack, and a device including the same, with improved cooling performance. [Background technology]

[0003] In modern society, as the use of portable devices such as mobile phones, laptops, camcorders, and digital cameras has become commonplace, the development of technologies related to these mobile devices is progressing vigorously. 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 address air pollution caused by existing gasoline-powered vehicles that use fossil fuels, and the need for the 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. Among these, lithium secondary batteries are attracting the most attention due to their advantages of being freely chargeable and dischargeable, having a low self-discharge rate, and having a high energy density.

[0005] Meanwhile, in the case of secondary batteries used in small devices, mainly two to three battery cells are used, while in the case of secondary batteries used in medium- to large-sized devices such as automobiles, medium- to large-sized battery modules in which a number of battery cells are electrically connected are used. Since it is preferable to manufacture medium- to large-sized battery modules to be as small and lightweight as possible, prismatic batteries and pouch-shaped batteries, which can be stacked with a high degree of integration and are light in weight relative to their capacity, are mainly used as battery cells for medium- to large-sized battery modules.

[0006] Meanwhile, the battery cells installed in the battery module generate a large amount of heat during charging and discharging, and if the temperature becomes higher than the appropriate temperature due to overcharging or other reasons, the performance may be degraded, and if the temperature rises excessively, there is a risk of explosion or fire. When a fire occurs inside a battery module, high-temperature heat, gas, or flames are emitted to the outside of the battery module, and at this time, the heat, gas, sparks, or flames emitted from one battery module may be transferred to other battery modules adjacent to each other at a small distance within the battery pack, and as a result, continuous thermal runaway may occur within the battery pack.

[0007] In order to prevent such a thermal runaway phenomenon, cooling members or heat dissipation members have been provided in conventional battery modules, and recently attempts have been made to apply water-cooled cooling members or water-cooled heat dissipation members in which cooling water is injected. However, even if a cooling (heat dissipation) member is provided in a battery module, a separation space is formed between the cooling (heat dissipation) member and the battery cells due to assembly or design reasons, and there is a problem that the cooling (heat dissipation) member cannot fully function due to the air gap caused by such a separation space.

[0008] Therefore, there is a need for a technology that can solve such problems of the conventional technology. Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a battery pack and a device including the same that can minimize a decrease in cooling performance caused by an air gap between a cooling member and a battery cell.

[0010] Another problem to be solved by the present invention is to provide a cooling fin capable of forming a stable contact surface with a heat sink, and a battery module and a battery pack including the same.

[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] A battery pack according to one embodiment of the present invention includes a battery module including a battery cell stack in which a plurality of battery cells are stacked, a pack frame that houses the battery module, and a heat sink located between the battery cell stack and the pack frame, and a cooling fin is disposed between two adjacent battery cells, and the cooling fin includes a main body portion that contacts the battery cells and an extension portion that extends to the upper side (z-axis) of the battery cell stack and is located adjacent to the heat sink, and the extension portion has a bent portion formed by bending in a direction different from the upper side (z-axis).

[0013] The heat sink may be located outside the battery module, and the extension may be in contact with the heat sink.

[0014] The bend formed in the extension may have an L-shaped spring shape or an S-shaped spring shape.

[0015] The cooling fins may be elastic.

[0016] The bend may be deformable depending on the distance between the battery cell stack and the heat sink.

[0017] The battery pack may include a heat dissipation layer formed between the battery cell stack and the heat sink.

[0018] The heat dissipation layer may be positioned discontinuously in the stacking direction of the battery cell stack.

[0019] The number of the cooling fins may be two or more, the two or more cooling fins may be spaced apart, and the heat dissipation layer may be formed in a plurality of pieces corresponding to the two or more cooling fins, respectively.

[0020] The heat dissipation layer may be in contact with the extension.

[0021] The heat dissipation layer may be located closer to a second point, which is an end of the extension portion, than to a first point where the body portion and the extension portion abut.

[0022] The heat dissipation layer may be in contact with the extension and the heat sink.

[0023] The battery module may include a side plate in contact with an outermost battery cell of the battery cell stack.

[0024] The number of the side plates is at least two, the battery cell stack is disposed between the two side plates, and the relative positions of the two side plates and the battery cell stack can be fixed by a retaining strap.

[0025] The retaining strap may include a locking claw formed at an end in the longitudinal direction, and the side plate may be formed with a locking groove corresponding to the locking claw.

[0026] A device according to another embodiment of the present invention includes at least one battery pack as described above.

[0027] According to another embodiment of the present invention, a cooling fin that forms a heat transfer path between a battery cell and a heat sink includes a main body portion positioned parallel to the battery cell and an extension portion extending from one end of the main body portion toward the heat sink, and the extension portion has a round shape curved to have a curvature.

[0028] The extension may include a first point having a first curvature and a second point having a second curvature, and the first curvature and the second curvature may be different from one another.

[0029] The extension may include a first point having a first slope and a second point having a second slope, the first slope and the second slope being different from each other.

[0030] On a cross section of the extension, an absolute value of the first slope may be smaller than an absolute value of the second slope, and the first point may be located farther from one end of the main body than the second point.

[0031] The first point may be located closer to the heat sink than the second point.

[0032] The second point may be out of contact with the heat sink.

[0033] The extension may be deformable according to a distance between the battery cell and the heat sink.

[0034] A plurality of the extensions may be formed on one cooling fin.

[0035] A heat dissipation layer may be positioned between the heat sink and a battery cell stack in which a plurality of the battery cells are stacked, and the extension may be in contact with the heat dissipation layer.

[0036] The heat dissipation layer may be formed in a plurality of pieces, the extension portion may be formed in a plurality of pieces on one cooling fin, and the plurality of heat dissipation layers may correspond to the plurality of extension portions formed on one cooling fin, respectively.

[0037] The heat dissipation layer may be positioned discontinuously in the stacking direction of the battery cell stack.

[0038] The number of the cooling fins may be two or more, the two or more cooling fins may be spaced apart, and the heat dissipation layer may be formed in a plurality of pieces corresponding to the two or more cooling fins, respectively.

[0039] The heat dissipation layer may be in contact with the extension and the heat sink.

[0040] A battery module according to another embodiment of the present invention includes at least one cooling fin as described above.

[0041] A battery pack according to still another embodiment of the present invention includes at least one cooling fin as described above. Effect of the Invention

[0042] According to the embodiment, the reduction in cooling performance due to the air gap between the cooling member and the battery cell is minimized, so that heat inside the battery pack can be effectively removed and a chain thermal runaway phenomenon can be prevented.

[0043] Furthermore, according to the embodiment, the contact surface between the heat sink and the cooling fins is stably formed, so that heat dissipation from the battery cells can be promoted and a chain reaction thermal runaway phenomenon can be prevented.

[0044] 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]

[0045] [Figure 1] 1 is an exploded perspective view showing a battery pack according to an embodiment of the present invention; [Diagram 2] 2 is a perspective view of a battery module included in the battery pack shown in FIG. 1. [Diagram 3]FIG. 2 is a perspective view of a heat sink included in the battery pack according to FIG. 1. [Figure 4] 2 is a cross-sectional view of the battery pack shown in FIG. 1 taken along the yz plane. [Diagram 5] 5 is a cross-sectional view showing a modified example of the battery pack in FIG. [Figure 6] FIG. 5 is a diagram showing the battery pack of FIG. 4 provided with a heat dissipation layer. [Figure 7] 11A and 11B are diagrams illustrating an example of a battery module or a battery pack equipped with cooling fins according to another embodiment of the present invention. [Figure 8] 13 is a diagram showing another example of a battery module or a battery pack having cooling fins according to still another embodiment of the present invention. FIG. [Figure 9] FIG. 2 is a perspective view of a cooling fin according to an embodiment of the present invention. [Figure 10] 13A and 13B are diagrams showing an experiment to confirm how the size of the contact surface formed differs depending on the shape of the cooling fin and the results thereof. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in order to enable those skilled in the art to easily carry out the present invention. The present invention may 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.

[0047] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0048] In addition, the size and thickness of each component shown in the drawings are arbitrarily enlarged or reduced for convenience of explanation, and it is obvious that the contents of the present invention are not limited to those shown. In the following drawings, the thickness of each layer is exaggerated to clearly express multiple layers and regions. In the following drawings, the thickness of some layers and regions is exaggerated for convenience of explanation.

[0049] In addition, when a layer, film, region, plate, etc. is described as being "on" or "above" another part, this should be interpreted as including not only the case where the corresponding layer, film, region, plate, etc. is "directly above" the other part, but also the case where there is another part between them. Conversely, when a corresponding layer, film, region, plate, etc. is described as being "directly above" another part, it means that there is no other part between them. 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 of gravity. Meanwhile, similar to the description of being "on" or "above" another part, the description of being "below" or "below" another part can also be understood with reference to the above content.

[0050] In addition, because the top / bottom of a particular component can be determined differently depending on the reference direction, throughout this specification, "top" or "bottom" is defined to mean the two opposing surfaces of the component on the z-axis.

[0051] Also, throughout the specification, when a part is said to "comprise" certain elements, this means that it may further include other elements, but not to the exclusion of other elements, unless specifically stated to the contrary.

[0052] Furthermore, throughout the specification, the term "on a plane" means when the relevant part is viewed from above, and the term "on a cross section" means when the relevant part is cut vertically and viewed from the side.

[0053] A battery pack according to an embodiment of the present invention will now be described.

[0054] First, the cooling fins of the present embodiment may be provided between battery cells in a battery pack or a battery module, and may promote heat dissipation from the battery cells to maintain a temperature within an appropriate range. In this case, a heat sink may be disposed above the battery cells, and the cooling fins may transfer heat from the battery cells to the heat sink to promote heat dissipation from the battery cells.

[0055] Fig. 1 is an exploded perspective view showing a battery pack according to an embodiment of the present invention, Fig. 2 is a perspective view of a battery module included in the battery pack according to Fig. 1, Fig. 3 is a perspective view of a heat sink included in the battery pack according to Fig. 1.

[0056] 1, 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 an inner surface of the pack frame 200, an end plate 400 that closes an open surface of the pack frame 200, a heat sink 500 disposed between the pack frame 200 and the battery cell stack 120, and a cooling fin 600 that dissipates heat of the battery cell 110 by contacting the battery cell 110. However, the components included in the battery pack 1000 are not limited thereto, and the battery pack 1000 may be provided with some of the above-mentioned components omitted or with other components not mentioned added, depending on the design.

[0057] 1 and 2, a battery module 100 provided in the present embodiment may have a module-less structure in which a module frame is omitted.

[0058] Generally, a conventional battery pack has a double assembly structure in which a battery module is formed by assembling a battery cell stack and a number of parts connected thereto, and the battery modules are then housed in a battery pack. At this time, since the battery module includes a module frame forming its outer surface, the conventional battery cells are doubly protected by the module frame of the battery module and the pack frame of the battery pack. However, such a double assembly structure not only increases the manufacturing cost and manufacturing process of the battery pack, but also has the disadvantage of reducing reassembly when some battery cells are defective. In addition, when a heat sink, which is a cooling member, is present outside the battery module, there is a problem that the heat transfer path between the battery cells and the heat sink becomes somewhat complicated.

[0059] Therefore, the battery module 100 of the present embodiment may be provided in the form of a "cell block" in which the module frame is omitted, and the battery cell stack 120 included in the cell block may be directly coupled to the pack frame 200 of the battery pack 1000. This allows the structure of the battery pack 1000 to be further simplified, and advantages in terms of manufacturing cost and manufacturing process may be obtained, and the weight of the battery pack may be reduced.

[0060] Hereinafter, the 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 for those having a battery cell stack 120 segmented into predetermined units for modularization, regardless of the presence or absence of a module frame, and the battery module 100 should be interpreted as including all normal battery modules and cell blocks having a module frame.

[0061] Referring to FIG. 2 , the battery module 100 of the present 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 in the stacking direction of the battery cell stack 120, retention straps 140 that surround the periphery of 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.

[0062] Although FIG. 2 illustrates a battery module 100 provided in the form of a cell block, the contents of this drawing do not exclude the case where a battery module 100 having a sealed structure having a module frame is applied to the battery pack 1000 of this embodiment.

[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 or rectangular shape that can maximize the number of cells stacked per unit area. For example, the battery cell 110 provided in a pouch shape may be manufactured by housing an electrode assembly including a positive electrode, a negative electrode, and a separator in a cell case of a laminate sheet, and then heat-sealing a sealing portion of the cell case. Meanwhile, although the positive and negative electrode leads of the battery cell 110 protrude in opposite directions in FIGS. 1 and 2, 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 a stack of multiple electrically connected battery cells 110 stacked in one direction. The direction in which the multiple 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 as including both + / - directions) as shown in Figures 1 and 2.

[0065] Meanwhile, since the battery cells 110 are arranged in one direction, the electrode leads of the battery cells 110 may be located on one side of the battery cell stack 120, or on both the one side and the other side opposite the one side. Thus, the side of the battery cell stack 120 on which the electrode leads are located is called the front or rear side of the battery cell stack 120, and in Figures 1 and 2, the front and rear sides of the battery cell stack 120 are shown as two sides facing each other on the x-axis.

[0066] Furthermore, the surface of the battery cell stack 120 on which the outermost battery cell 110 is located is referred to as the side surface of the battery cell stack 120, and in Figures 1 and 2 the side surfaces of the battery cell stack 120 are shown as two surfaces facing each other on the y axis.

[0067] The side plates 130 may be provided to maintain the overall shape of the battery cell stack 120. The side plates 130 are plate-like members and can complement the rigidity of the cell blocks in place of a module frame. The side plates 130 are disposed on both ends of the battery cell stack 120 in the stacking direction, and can contact the outermost battery cells 110 on both sides of the battery cell stack 120.

[0068] The side plate 130 may be made of various materials and may be provided by 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 yet another example, the side plate 130 may be made of an elastic material such that a part of its shape is deformed in response to a volume change of the battery cell stack 120 due to swelling.

[0069] The retaining 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 retaining 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 retaining straps 140 may connect the two side plates 130 across the battery cell stack 120. In this way, the retaining straps 140 may prevent the distance between the two side plates 130 from increasing beyond a certain range, and therefore the overall shape of the cell block may be maintained within a certain range.

[0070] The holding strap 140 may have locking claws at both ends in the longitudinal direction for stable connection with the side plate 130. The locking claws may be formed by bending both ends in the longitudinal direction of the holding strap 140. Meanwhile, the side plate 130 may have locking grooves at positions corresponding to the locking claws, and the holding strap 140 and the side plate 130 may be stably connected by the connection between the locking claws and the locking grooves.

[0071] The retention straps 140 may be made of a variety of materials or may be manufactured using a variety of methods, including, for example, a material having elasticity, which allows the volumetric change of the battery cell stack 120 due to swelling to be within a certain range.

[0072] Meanwhile, the retaining strap 140 is for fixing the relative position between the side plate 130 and the battery cell stack 120, and may be provided in a form different from that shown in the drawing, so long as its purpose as a "fixing member" is achieved. For example, the fixing member may be provided in the form of a long bolt that crosses between the two side plates 130. The side plate 130 may have a groove into which the long bolt is inserted, and the long bolt may be simultaneously coupled to the two side plates 130 through the groove, thereby fixing the relative positions of the two side plates 130. The long bolt may be provided at an edge of the side plate 130, preferably at a position close to the apex of the side plate 130. Depending on the design, the retaining strap 140 may be replaced with the long bolt described above, or both the retaining strap 140 and the long bolt may be provided to the cell block.

[0073] The busbar frame 150 may be located on one side of the battery cell stack 120 to cover one side of the battery cell stack 120 and guide the connection of the battery cell stack 120 to an external device. The busbar frame 150 may be located on the front or rear side of the battery cell stack 120. Two busbar frames 150 are provided, one on the front side and the other on the rear side of the battery cell stack 120. A busbar is attached to the busbar frame 150, and thus, the electrode leads of the battery cell stack 120 are connected to the busbar, thereby electrically connecting the battery cell stack 120 to an external device.

[0074] 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.

[0075] The pack frame 200 may be for protecting the battery module 100 and electrical components connected thereto from external physical impacts. The pack frame 200 accommodates the battery module 100 and electrical components connected thereto in an internal space of the pack frame 200. Here, the pack frame 200 includes an internal surface and an external surface, and the internal space of the pack frame 200 is defined by the internal surface.

[0076] There may be a plurality of battery modules 100 housed within the pack frame 200. A plurality of battery modules 100 are referred to as a "module assembly." The module assembly is arranged in rows and columns within the pack frame 200. Here, a "row" refers to a set of battery modules 100 arranged in one direction, and a "column" refers to a set of battery modules 100 arranged in a direction perpendicular to the one direction. For example, the battery modules 100 may be arranged along the stacking direction of the battery cell stack shown in FIG. 1 to form a module assembly in one row or column.

[0077] The pack frame 200 is provided in a hollow shape that is open in one direction. For example, as shown in FIG 1, a plurality of battery modules 100 may be positioned consecutively in a stacking direction of the battery cells 110, and the pack frame 200 may have a hollow shape that is open in the stacking direction.

[0078] The structure of the pack frame 200 may be varied. For example, as shown in Fig. 1, 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 may be provided to surround the upper surface of the module assembly and two surfaces on the x-axis.

[0079] The pack frame 200 may include a portion having high thermal conductivity 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 where insulation is required. The portion of the pack frame 200 to which the insulating film or insulating coating is applied may be referred to as an insulating portion.

[0080] 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 heat sink 500 (described later) and the upper frame 220.

[0081] 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 also be a member provided in a plate shape.

[0082] The resin layer 300 may be made of various materials, and the function of the resin layer 300 varies depending on the material. For example, the resin layer 300 may be made of an insulating material, and electron transfer between the battery module 100 and the pack frame 200 may be prevented through the insulating resin layer 300. 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 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.

[0083] The end plate 400 may serve to protect the battery module 100 and electrical components connected thereto from external physical impact by sealing an open side of the pack frame 200. Each edge of the end plate 400 may be coupled to a corresponding edge of the pack frame 200 by a method such as welding. Two end plates 400 are provided to seal the two open sides of the pack frame 200, and may be made of a metal material having a predetermined strength.

[0084] The end plate 400 has an opening 410 for exposing an inlet / outlet port 530 of a heat sink 500 described below, and is fitted with a connector 420 for LV (Low voltage) connection or HV (High voltage) connection with an external device.

[0085] The heat sink 500 may be for cooling the inside of the battery pack 1000 by dissipating heat generated from the battery cells 110. Considering that high-temperature air or gas released when the battery cells 110 ignite mainly moves in the direction opposite to gravity, it is preferable that the heat sink 500 is located above the battery cells 110 as shown in Fig. 1. However, this is not necessarily the case, and the heat sink 500 may be located below the battery cells 110 for various design reasons.

[0086] The heat sink 500 may be a water-cooled heat sink 500 into which a coolant, for example, cooling water, is injected. In this case, any coolant may be used for the heat sink 500 as long as it can dissipate heat from the battery cells 110 by moving along a flow path inside the heat sink 500.

[0087] 3, the heat sink 500 may include an upper plate 510, a lower plate 520, and an inlet / outlet port 530. The heat sink 500 is formed by combining the upper plate 510 and the lower plate 520. An empty space is formed between the combined upper plate 510 and the lower plate 520, and cooling water may be injected into the empty space through the inlet / outlet port 530. The cooling water is supplied through the inlet port 530 and discharged to the outlet port 530.

[0088] A groove 540 is formed in the heat sink 500, which determines the flow of the cooling water. Figure 3 shows an example of this, in which the flow of the cooling water is formed in a U-shape by the groove 540 formed along the length of the heat sink 500.

[0089] Meanwhile, in the above description, the heat sink 500 is provided outside the battery module 100, but this is not necessarily the case, and the heat sink 500 may be disposed inside the battery module 100. When the heat sink 500 is disposed inside the battery module 100, heat transfer between the heat sink 500 and the battery cells 110 can be easily achieved even if the battery module 100 has a closed structure having a module frame.

[0090] As described above, the heat sink 500 is provided in the battery pack 1000 or the battery module 100, so that heat generated in the battery cells 110 is absorbed and released by the heat sink 500. However, since it is nearly impossible to design the heat sink 500 and the battery cells 110, which are assembled after being manufactured, to be in perfect contact with each other in the battery pack 1000 or the battery module 100, a space may usually be generated between the heat sink 500 and the battery cells 110. As described above, an air gap or an air pocket is formed in the space generated between the heat sink 500 and the battery cells 110, so that heat transfer from the battery cells 110 to the heat sink 500 is not smooth, and the cooling efficiency of the heat sink 500 may be somewhat reduced.

[0091] In order to solve the problem of the cooling efficiency being reduced due to air pockets, etc., a method of forming a heat transfer path by filling the above-mentioned 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 unit price 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 the present embodiment may be provided with a cooling fin 600 for minimizing the cooling efficiency being reduced due to the air gap.

[0092] Fig. 4 is a cross-sectional view of the battery pack according to Fig. 1 cut along the yz plane. Fig. 5 is a cross-sectional view showing a modified example of the battery pack of Fig. 4. Fig. 6 is a view showing a case where a heat dissipation layer is provided in the battery pack of Fig. 4. Here, Figs. 4 to 6 show cross sections of the battery pack in an exploded state, and the arrows in Figs. 4 to 6 indicate the joining direction of each component in the battery pack.

[0093] 4 to 6, the cooling fin 600 of the present embodiment may be for maintaining the temperature inside the battery pack 1000 or the battery module 100 within an appropriate range.

[0094] The cooling fins 600 are provided between the battery cells 110 facing one side thereof, and the cooling fins 600 can absorb heat generated from the battery cells 110 by contacting one side of the battery cells 110. The cooling fins 600 transfer the heat absorbed from the battery cells 110 to the heat sink 500. A part of the cooling fins 600 may be present in a space between the battery cells 110 and the heat sink 500, and thus the heat of the battery cells 110 is transferred to the heat sink 500 through the cooling fins 600. The cooling fins 600 are present in the space between the battery cells 110 and the heat sink 500, and thus the amount of heat dissipation interface material used in the battery module 100 or the battery pack 1000 can be minimized, and the manufacturing cost of the battery module 100 or the battery pack 1000 can be reduced or the manufacturing process can be simplified.

[0095] The cooling fin 600 includes a body portion 610 in surface contact with one side of the battery cell 110, and an extension portion 620 extending beyond the upper surface of the battery cell stack 120 and positioned adjacent to the heat sink 500. The body portion 610 is in contact with the battery cell 110 to receive heat from the battery cell 110, and the extension portion 620 is positioned adjacent to the heat sink 500 to release the heat transferred toward the heat sink 500. Here, the extension portion 620 of the cooling fin 600 may be positioned adjacent to the lower plate 520 of the heat sink 500 or may be positioned to contact the lower plate 520.

[0096] A plurality of cooling fins 600 are provided in the battery cell stack 120. The cooling fins 600 may be provided between all of the two adjacent battery cells 110, but this is not necessarily the case, and the cooling fins 600 may be provided only on some of the two adjacent battery cells 110. In this case, when the cooling fins 600 are provided only on some of the two adjacent battery cells 110, it is preferable that the cooling fins 600 are arranged at regular intervals so that the effect of the cooling fins 600 is equally exerted in the battery cell stack 120.

[0097] The cooling fins 600 may be made of a material having high thermal conductivity. For example, the cooling fins 600 may be made of aluminum, gold, silver, copper, platinum, or an alloy including these. The cooling fins 600 made of a material having high thermal conductivity may have a much lower thermal resistance than air, and the cooling fins 600 may allow heat to be transferred more smoothly between the battery cells 110 and the heat sink 500.

[0098] 4 and 5, the cooling fin 600 of the present embodiment may have an elastic structure. Specifically, the extension 620 of the cooling fin 600 is provided in the form of a spring having a bend. The extension 620 may have a bend formed by being bent in a direction different from the upper side (z-axis) of the battery cell stack 120.

[0099] For example, the extension 620 of the cooling fin 600 extends to the outside of the battery cell stack 120 along the z-axis direction as shown in FIG. 4, but the extension direction can be bent or curved to have an x-axis or y-axis component. When a part of the cooling fin 600 is bent, the absolute length of the cooling fin 600 present in the space between the battery cell 110 and the heat sink 500 becomes longer. In this way, when a bent part is formed in the cooling fin 600, the cooling fin 600 crosses more of the space in the air gap, so that the deterioration of cooling performance due to the air gap between the battery cell 110 and the heat sink 500 can be minimized. Here, the "absolute length" of the cooling fin 600 means the length before the bend is formed, or the length when the cooling fin 600 with the bend is formed straight. Meanwhile, the shape of the bent part of the cooling fin 600 provided as shown in FIG. 4 is called an L-shaped spring shape.

[0100] As another example, the extension 620 of the cooling fin 600 may be bent or folded two or more times to have an x-axis or y-axis component as shown in FIG. 5. As the number of bends or the length section of the bent portion formed in the cooling fin 600 increases, the absolute length of the cooling fin 600 present in the space between the battery cell 110 and the heat sink 500 in FIG. 5 becomes longer than that in FIG. 4. Compared to the cooling fin 600 in FIG. 4, the cooling fin 600 in FIG. 5 exists in the air gap space between the battery cell 110 and the heat sink 500 more than in FIG. 4, so that the effect of the cooling fin 600 can be maximized as the number of bends or the length section of the bent portion of the cooling fin 600 increases. Meanwhile, the shape of the bent portion of the cooling fin 600 formed by bending it two or more times as shown in FIG. 5 is called an S-shaped spring shape.

[0101] The cooling fin 600 may be an elastic body whose shape is deformed by an external force. In order to achieve a good heat dissipation effect by the cooling fin 600, it is preferable that the end of the cooling fin 600 in the longitudinal direction contacts the heat sink 500. However, since it is impossible to predict the size of the space formed between the battery cell 110 and the heat sink 500 in the battery pack 1000 or the battery module 100, it is very difficult to design an appropriate size of the cooling fin 600. If the cooling fin 600 is provided as an elastic body, even if the extension 620 of the cooling fin 600 is designed to be larger than the size of the actual air gap, the extension 620 of the cooling fin 600 is appropriately deformed during the assembly process to fit the size of the air gap between the battery cell 110 and the heat sink 500, making it easier to design the cooling fin 600. That is, if the cooling fin 600 is provided as an elastic body, the length of the extension 620 is longer than the distance between the battery cell stack 120 and the heat sink 500 when no external force is applied. Here, the length of the extension 620 may be the length on the z-axis that the extension 620 occupies on the cooling fin 600. In this case, the distance between the battery cell stack 120 and the heat sink 500 refers to the distance on the z-axis.

[0102] Here, the cooling fin 600 is elastic because the cooling fin 600 is made of an elastic material such as a 10xx aluminum alloy, but this is not necessarily the case. In other words, even if the cooling fin 600 is not made of an elastic material or is made of a material with a somewhat low elasticity, the cooling fin 600 can exhibit all the effects of the cooling fin 600 made of an elastic material as long as it has the elastic structure as shown in Figs. 4 and 5.

[0103] 4 and 5, the portion of the cooling fin 600 marked "overlap" is compressed by an external force, so that the extension portion 620 of the cooling fin 600 conforms to the size of the air gap between the battery cell 110 and the heat sink 500. At this time, the compression allows a larger portion of the cooling fin 600 to contact the heat sink 500, so that the heat dissipation effect of the cooling fin 600 can be improved.

[0104] Meanwhile, since the cooling fins 600 are provided, it is possible to not use any heat dissipation interface material in the battery pack 1000 at all, but in order to further improve the cooling performance of the battery pack 1000, it is also possible to apply an additional heat dissipation interface material to the battery pack 1000 provided with the cooling fins 600.

[0105] Referring to FIG. 6 , a heat dissipation layer 700 is provided in at least a portion of the space between the battery cell 110 and the heat sink 500 .

[0106] The heat dissipation layer 700 can improve the cooling performance of the battery pack 1000 by providing a heat transfer path in the space between the battery cell 110 and the heat sink 500. The heat dissipation layer 700 can be formed of a heat transfer material having a lower thermal resistance than air, i.e., a heat dissipation interface material. Since the heat dissipation layer 700 is formed of a material having high thermal conductivity, it can contribute to preventing a decrease in cooling performance due to an air gap between the battery cell 110 and the heat sink 500.

[0107] At this time, since the battery pack 1000 of the present embodiment includes the above-mentioned cooling fins 600, the size (volume) of the heat dissipation layer 700 is significantly reduced compared to a case where the heat dissipation layer 700 is formed but the cooling fins 600 are not used. Therefore, even though the battery pack 1000 of Fig. 6 includes the heat dissipation layer 700, the amount of heat dissipation interface material used can be minimized as long as the battery pack 1000 includes the cooling fins 600, and therefore the manufacturing cost can be significantly reduced.

[0108] For example, the heat dissipation layer 700 may be formed only around the cooling fin 600, specifically, the extension portion 620. Also, the heat dissipation layer 700 may be formed only around one end of the extension portion 620. In other words, when a first point where the body portion 610 and the extension portion 620 abut on the cooling fin 600 and a second point which is the end of the extension portion 620 are defined, the heat dissipation layer 700 is located closer to the second point than the first point. Here, the end of the extension portion 620 corresponds to the end of the cooling fin 600.

[0109] 6, the heat dissipation layer 700 is discontinuously formed at a position corresponding to the cooling fins 600. Specifically, the cooling fins 600 are provided in a plurality of pieces and are spaced apart from each other, and the heat dissipation layer 700 is formed in a plurality of pieces so as to correspond to each of the cooling fins 600. That is, the heat dissipation layer 700 may be discontinuously present in the stacking direction of the battery cell stack 120, thereby minimizing the use of heat dissipation interface material for improving the performance of the cooling fins 600.

[0110] The heat dissipation layer 700 can improve the heat dissipation performance of the cooling fin 600. As described above, even if the cooling fin 600 is provided as an elastic body, a somewhat large external force must be applied to deform the shape of the cooling fin 600, so the actual deformation level of the cooling fin 600 is not large. In addition, even if the cooling fin 600 is deformed, the heat conduction area between the cooling fin 600 and the heat sink 500 is not large enough. However, when the heat dissipation layer 700 is added to the end of the cooling fin 600 as in the present embodiment, a large heat conduction path between the cooling fin 600 and the heat sink 500 is formed by the heat dissipation layer 700, so that the heat dissipation performance of the cooling fin 600 can be further improved.

[0111] The heat dissipation layer 700 is in contact with the cooling fin 600. The heat dissipation layer 700 is formed around the extension portion 620 of the cooling fin 600, thereby improving the thermal capacity of the cooling fin 600. The heat dissipation layer 700 is located between the cooling fin 600 and the heat sink 500, and may be in contact with both the cooling fin 600 and the heat sink 500. At this time, the heat dissipation layer 700 contributes to the transfer of heat between the cooling fin 600 and the heat sink 500, and thus the transfer of heat between the cooling fin 600 and the heat sink 500 is promoted by the heat dissipation layer 700.

[0112] Here, the cooling fins 600 may simply contact the heat dissipation layer 700, or may be formed so that the cooling fins 600 penetrate the heat dissipation layer 700 or a portion of the cooling fins 600 is impregnated in the heat dissipation layer 700. As the contact area between the cooling fins 600 and the heat dissipation layer 700 increases, such as when the cooling fins 600 penetrate or are impregnated in the heat dissipation layer 700, the heat transfer between the two components becomes easier.

[0113] The heat dissipation layer 700 compensates for errors in design or assembly of the cooling fin 600. In particular, the cooling fin 600 may not contact the heat sink 500 due to errors in design or assembly, but if the heat dissipation layer 700 is located around the cooling fin 600, heat conduction between the cooling fin 600 and the heat sink 500 through the heat dissipation layer 700 can be achieved, thereby eliminating such design errors. In addition, since the heat dissipation layer 700 may be compressed to some extent by the elastic force of the cooling fin 600 during the assembly process of the battery module 100, even if the cooling fin 600 and the heat sink 500 are manufactured / designed to be in contact with each other or to be somewhat spaced apart from each other, the heat dissipation layer 700 can more stably form a heat transfer path for the cooling fin 600. Therefore, the provision of the heat dissipation layer 700 in the battery pack 1000 allows more freedom in designing the heat sink 500 or the cooling fin 600.

[0114] The heat dissipation layer 700 is formed by hardening a liquid material. For example, after the battery module 100 is disposed inside the pack frame 200, a liquid resin is applied thereto, and the applied resin is hardened to form the heat dissipation layer 700.

[0115] FIG. 7 is a diagram showing an example of a battery module or a battery pack to which cooling fins according to a modification of FIG. 4 are attached, as still another embodiment of the present invention.

[0116] 7, the cooling fins 600 of the present embodiment are provided between the battery cells 110 facing one side thereof to promote heat dissipation from the battery cells 110. The cooling fins 600 can absorb heat generated from the battery cells 110 by contacting one side of the battery cells 110. The cooling fins 600 can be connected to a heat sink 500 located on the upper side of the battery cells 110, and can transfer the heat absorbed from the battery cells 110 to the heat sink 500. Here, the cooling fins 600 can be in contact with the heat sink 500, or can be connected, coupled or attached via a heat dissipation layer 700 described below.

[0117] The cooling fin 600 includes a main body 610 arranged parallel to one surface of the battery cell 110, and an extension 620 extending from one end of the main body 610. The main body 610 is located close to the battery cell 110 to receive heat from the battery cell 110, and the extension 620 is located close to the heat sink 500 to release the transferred heat toward the heat sink 500.

[0118] The body 610 is in surface contact with one surface of the battery cell 110. Depending on the design, a thermally conductive material may be disposed between the body 610 and one surface of the battery cell 110, and the body 610 and the battery cell 110 may be in close contact with each other through the thermally conductive material.

[0119] The extension portion 620 may extend from one end of the body portion 610 toward the upper side (+z-axis direction) of the battery cell stack 120 and be positioned adjacent to the heat sink 500. Here, the extension portion 620 of the cooling fin 600 may be positioned adjacent to a lower plate located on the lower surface of the heat sink 500 or may be positioned to contact the lower plate.

[0120] The extension 620 may be formed to have a long width or a short width at one edge of the body 610. When the extension 620 has a short width, a plurality of extensions 620 are formed on one cooling fin 600.

[0121] In this embodiment, a plurality of cooling fins 600 may be provided on the battery cell stack 120 in which a plurality of battery cells 110 are stacked in one direction. The cooling fins 600 may be provided between every two adjacent battery cells 110, but this is not necessarily the case, and the cooling fins 600 may be provided only on some of the two adjacent battery cells 110. In this case, when the cooling fins 600 are provided only on some of the two adjacent battery cells 110, it is preferable that the cooling fins 600 are arranged at regular intervals so that the effect of the cooling fins 600 is equally exerted on the battery cell stack 120.

[0122] Also, in this embodiment, the cooling fins 600 may be made of a material with high thermal conductivity. For example, the cooling fins 600 may be made of aluminum, gold, silver, copper, platinum, or an alloy containing these metals. The cooling fins 600 made of a material with high thermal conductivity have a much lower thermal resistance than air, and the cooling fins 600 may allow heat to be transferred more smoothly between the battery cells 110 and the heat sink 500.

[0123] In this embodiment, the cooling fin 600 may be an elastic body whose shape is deformed by an external force. In order to achieve a good heat dissipation effect by the cooling fin 600, it is preferable that the end (the end on the z-axis, i.e., the end in the longitudinal direction) of the cooling fin 600 contacts the heat sink 500. However, since it is impossible to predict the size of the space formed between the battery cell 110 and the heat sink 500 in the battery pack 1000 or the battery module 100, it is very difficult to design an appropriate size of the cooling fin 600. If the cooling fin 600 is provided as an elastic body, even if the extension 620 of the cooling fin 600 is designed to be larger than the actual air gap size, the extension 620 of the cooling fin 600 is appropriately deformed during the assembly process to fit the air gap size between the battery cell 110 and the heat sink 500, making it easier to design the cooling fin 600. That is, when the cooling fin 600 is provided as an elastic body, the length of the extension 620 in the absence of an external force is longer than the distance between the battery cell stack 120 and the heat sink 500. Here, the length of the extension 620 may be the length on the z-axis that the extension 620 occupies in the cooling fin 600. In this case, the distance between the battery cell stack 120 and the heat sink 500 refers to the distance on the z-axis.

[0124] Here, the cooling fins 600 may be elastic because the cooling fins 600 are made of an elastic material such as a 10xx aluminum alloy, but this is not necessarily the case. In other words, even if the cooling fins 600 are not made of an elastic material or made of a material with a somewhat low elasticity, the cooling fins 600 can exhibit all the effects of the cooling fins 600 made of an elastic material if they are formed into a deformable shape.

[0125] 7 again, the cooling fin 600 of this embodiment is provided in a round shape. The extension 620 of the cooling fin 600 may have a round shape curved in the thickness direction. The extension 620 is formed by bending in a direction different from the upper side (z-axis) of the battery cell stack 120. The extension 620 extends to the outside of the battery cell stack 120 along the z-axis direction, but may be folded or bent so that the extension direction has a y-axis component.

[0126] The extension 620 may have a curvature. The curvature of the extension 620 varies depending on the position. The extension 620 includes a first point 622 having a first curvature and a second point 624 having a second curvature. Here, the first curvature and the second curvature may be different from each other.

[0127] The extension 620 is formed so that its cross section has an inclination. Here, the cross section of the extension 620 refers to a cross section (yz plane) in a direction perpendicular to the bottom surface of the battery cell stack 120 or the ground. The cross section of the extension 620 may be a plane parallel to the stacking direction of the battery cells 110 or the thickness direction of the extension 620. Here, the inclination is calculated based on the direction parallel to the bottom surface of the battery cell stack 120 or the ground. On the cross section of the extension 620, the inclination is calculated based on the stacking direction of the battery cells 110 or the thickness direction of the extension 620 (y axis).

[0128] The slope of the extension 620 does not have to be constant, but rather the extension 620 is formed such that the absolute value of the slope gradually decreases within a predetermined section.

[0129] For example, the extension 620 may have a slope with a larger absolute value closer to one end of the extension 620 that abuts against one end of the body 610, and a slope with a smaller absolute value closer to the other end. However, this is not the case when the other end of the extension 620 is formed in a raised shape, as shown in the enlarged view of FIG.

[0130] As another example, the extension 620 may have a slope value with a smaller absolute value as it is farther from one end of the body 610, from a point where it abuts against one end of the body 610 to a point located closest to the heat sink 500. The extension 620 may have a slope value with a smaller absolute value as it is closer to the heat sink 500, from the point where it abuts against one end of the body 610 to the point where it is closest to the heat sink 500, in the extension direction extending from one end of the body 610 until it contacts the heat sink 500. In this case, the point of the extension 620 located closest to the heat sink 500 may have a slope value of 0 or close to it.

[0131] The extension 620 may include a first point 622 having a first slope and a second point 624 having a second slope. The first slope and the second slope may be different from each other. The absolute value of the first slope may be less than the absolute value of the second slope.

[0132] Here, the first point 622 is located farther from the body 610 than the second point 624. The first point 622 is located closer to the heat sink 500 than the second point 624. The second point 624 does not contact the heat sink 500. The second point 624 is non-contact with the heat sink 500. The first point 622 may contact the heat sink 500, but this is not necessarily the case.

[0133] Also, here, the first point 622 may be a point located closest to the heat sink 500 , and the second point 624 may be a point located between the first point 622 and one end of the main body portion 610 .

[0134] As will be described below, when a heat dissipation layer 700 is formed on the underside of the heat sink 500, the first point 622 contacts the heat dissipation layer 700. The second point 624 may also contact the heat dissipation layer 700, but this is not required and may or may not be the case depending on the design.

[0135] Referring again to FIG. 7, a heat dissipation layer 700 may be formed in the space between the battery cell 110 and the heat sink 500 to stably form thermal contact between the cooling fins 600 and the heat sink 500 and to increase the thermal contact area.

[0136] The heat dissipation layer 700 can improve the cooling performance of the heat sink 500 by providing a heat transfer path in the space between the battery cell 110 and the heat sink 500. The heat dissipation layer 700 is made of a thermal transfer material having a lower thermal resistance than air, i.e., a thermal interface material (TIM). Since the heat dissipation layer 700 is made of a material with high thermal conductivity, it can contribute to preventing a decrease in cooling performance caused by an air gap between the battery cell 110 and the heat sink 500.

[0137] The heat dissipation layer 700 is formed on the bottom surface of the heat sink 500. The heat dissipation layer 700 may be in contact with the bottom plate of the heat sink 500.

[0138] The heat dissipation layer 700 may be in contact with the cooling fin 600. The heat dissipation layer 700 may be formed around the extension portion 620 of the cooling fin 600, thereby improving the thermal capacity of the cooling fin 600. The heat dissipation layer 700 may be located between the cooling fin 600 and the heat sink 500, and may be in contact with both the cooling fin 600 and the heat sink 500. In this case, the heat dissipation layer 700 may contribute to the transfer of heat between the cooling fin 600 and the heat sink 500, and thus the transfer of heat between the cooling fin 600 and the heat sink 500 may be promoted by the heat dissipation layer 700.

[0139] Here, the cooling fins 600 may simply contact the heat dissipation layer 700, or may be formed so that the cooling fins 600 penetrate the heat dissipation layer 700 or a portion of the cooling fins 600 is impregnated in the heat dissipation layer 700. As the contact area between the cooling fins 600 and the heat dissipation layer 700 increases, such as when the cooling fins 600 penetrate or are impregnated in the heat dissipation layer 700, the heat transfer between the two components becomes easier.

[0140] The heat dissipation layer 700 can improve the heat dissipation performance of the cooling fin 600. As described above, even if the cooling fin 600 is provided as an elastic body, a somewhat large external force must be applied to deform the shape of the cooling fin 600, so the actual deformation level of the cooling fin 600 is not large. In addition, even if the cooling fin 600 is deformed, the heat conduction area between the cooling fin 600 and the heat sink 500 is not large enough. However, when the heat dissipation layer 700 is added to the lower surface of the cooling fin 600 as shown in the figure, a large heat conduction path between the cooling fin 600 and the heat sink 500 is formed by the heat dissipation layer 700, so that the heat dissipation performance of the cooling fin 600 can be further improved.

[0141] The heat dissipation layer 700 compensates for errors in design or assembly of the cooling fin 600. Specifically, the cooling fin 600 may not contact the heat sink 500 due to errors in design or assembly, but if the heat dissipation layer 700 is located around the cooling fin 600, heat conduction between the cooling fin 600 and the heat sink 500 through the heat dissipation layer 700 can be achieved, thereby eliminating such design errors. In addition, since the heat dissipation layer 700 may be compressed to some extent by the elastic force of the cooling fin 600 during the assembly process of the battery module or battery pack, even if the cooling fin 600 and the heat sink 500 are manufactured / designed to be in contact with each other or to be somewhat spaced apart from each other, the heat dissipation layer 700 can more stably form a heat transfer path for the cooling fin 600. Therefore, the provision of the heat dissipation layer 700 allows more freedom in the design of the heat sink 500 or the cooling fin 600.

[0142] The heat dissipation layer 700 may be formed to have a large width so as to cover more than half of the width (x-axis direction) of the battery cell 110. Alternatively, the heat dissipation layer 700 may be formed to have a width smaller than half of the width (x-axis direction) of the battery cell 110. When a plurality of extensions 620 are formed on one cooling fin 600, the heat dissipation layer 700 may be formed to have a large width so as to correspond to all of the extensions 620, or a plurality of narrow-width heat dissipation layers 700 may be formed to correspond to each extension 620. By forming a plurality of narrow-width heat dissipation layers 700, the amount of heat dissipation interface material used in the battery module or battery pack can be minimized, thereby achieving cost reduction.

[0143] The heat dissipation layer 700 is formed in an elongated shape extending in the stacking direction of the battery cells 110. However, this is not necessarily the case, and the heat dissipation layer 700 may be positioned at intervals in the stacking direction of the battery cells 110. This will be described later with reference to FIG.

[0144] The heat dissipation layer 700 is formed by hardening a liquid material. For example, after the battery cell stack 120 is disposed inside the frame of the battery module or battery pack, a liquid resin may be applied thereto, and the applied resin may be hardened to form the heat dissipation layer 700.

[0145] FIG. 8 is a diagram showing another example of a battery module including cooling fins according to a modification of FIG. 7, according to still another embodiment of the present invention.

[0146] 8, the heat dissipation layer 700 may be discontinuously formed at a position corresponding to the cooling fin 600. The heat dissipation layer 700 may be formed only around the cooling fin 600, specifically, the extension portion 620. The heat dissipation layer 700 may also be formed only around one end of the extension portion 620. Specifically, the cooling fins 600 provided in a plurality of pieces are spaced apart, and at this time, the heat dissipation layer 700 is formed in a plurality of pieces corresponding to the plurality of cooling fins 600, respectively. The heat dissipation layer 700 may be discontinuously formed in the stacking direction of the battery cell stack 120. Considering that the unit price of the heat dissipation interface material used in the heat dissipation layer 700 is high, it is preferable to minimize the use of the heat dissipation interface material by forming the heat dissipation layer 700 discontinuously.

[0147] FIG. 9 shows a perspective view of a cooling fin according to the embodiment of FIGS.

[0148] FIG. 10 is a diagram showing an experiment for confirming the size of the contact surface formed differently depending on the shape of the cooling fin in the above-mentioned embodiment and the results thereof.

[0149] 10, unlike the above, the cooling fin 600 may be formed to have two flat parts with different inclinations due to bending without having a curvature. For convenience of explanation, such a shape will be called AA type, and a shape with a curvature as in this embodiment will be called BB type. The cooling fin 600 used in the experiment of FIG. 10 was made of 10xx series aluminum material and had a thickness of 0.4 mm.

[0150] As described above, the length of the extension 620 of the cooling fin 600 may be longer than the distance between the battery cell stack 120 and the heat sink 500, and thus the extension 620 may be deformed to stably form a heat transfer path between the cooling fin 600 and the heat sink 500. The heat sink 500 may be positioned above the extension 620 shown as "overlap dimension" in Fig. 10, and the lower surface of the heat sink 500 during assembly may be pressed until it is positioned at the dotted line, thereby deforming the extension 620 and reducing its length on the z-axis. After assembly, the lower surface of the heat sink 500 is positioned on the dotted line, and the heat dissipation layer 700 is positioned in the section from the dotted line to the solid line below it.

[0151] Here, the amount of change in length of the extension 620 that is deformed by pressure is referred to as a first overlap length OL1, and the first overlap length OL1 of the extension 620 shown in Fig. 10 may be about 1 mm. That is, the length of the extension 620 on the z-axis may be designed to be about 1 mm larger than the distance between the battery cell stack 120 and the heat sink 500.

[0152] In addition, the extension 620 after assembly of the heat sink 500 may contact the heat dissipation layer 700 formed on the lower surface of the heat sink 500, and the degree of overlap between the extension 620 and the heat dissipation layer 700 is referred to as a second overlap length OL2. The second overlap length OL2 is calculated based on the length of the extension 620 before deformation, and the second overlap length OL2 of the extension 620 shown in Fig. 10 may be about 3 mm. That is, the thickness of the heat dissipation layer 700 used in the experiment may be about 2 mm.

[0153] 10, in order to compare the size of the contact area between the cooling fin 600 and the heat dissipation layer 700 or the heat sink 500 depending on the shape of the cooling fin 600, the cooling fin 600 was inserted between a plate-like member separately manufactured similar to the battery cell 110, the heat dissipation layer 700 was positioned, and then the upper surface of the heat dissipation layer 700 was pressed with an acrylic plate. Here, the plate-like member corresponds to the battery cell 110, and the acrylic plate corresponds to the heat sink 500.

[0154] The heat dissipation layer 700 includes two heat dissipation layers, a first heat dissipation layer and a second heat dissipation layer, each having a different width, and the contact lengths between the first heat dissipation layer with the narrower width and the cooling fin 600 are denoted as AA1 and BB1, and the contact lengths between the second heat dissipation layer with the wider width and the cooling fin 600 are denoted as AA2 and BB2, respectively. The contact area between the cooling fin 600 and the heat dissipation layer 700 is proportional to the size of the contact length.

[0155] 10, it can be seen that the difference in contact length depends on the shape of the cooling fin 600. Here, the numbers on the horizontal axis indicate each cooling fin 600, and the numbers on the vertical axis indicate the length value of the contact area formed between each cooling fin 600 and the heat dissipation layer 700.

[0156] Referring to the experimental results, the overall contact length of the AA type cooling fin 600 was greater than that of the BB type cooling fin 600. However, the experimental results for the AA type cooling fin 600 showed a large deviation in the contact length depending on the position, with non-contact occurring at positions 14, 15, 16, and 20. Considering this, a problem may occur in which the AA type cooling fin 600 cannot contact the heat dissipation layer 700 due to design or assembly errors.

[0157] On the other hand, when examining the experimental results of the BB type cooling fins 600, it can be seen that there is no large deviation in the contact length formed between each cooling fin 600 and the heat dissipation layer 700. Also, unlike the experimental results of the AA type cooling fins 600, no non-contact occurred.

[0158] If the contact area between each cooling fin 600 provided between the battery cells 110 and the heat dissipation layer 700 is not uniform, the heat dissipation of some of the battery cells 110 is reduced, resulting in temperature deviation in the battery cell stack 120, making it difficult to effectively control heat transfer or thermal runaway. Referring to the experimental results, it is difficult for the AA type cooling fin 600 having a flat shape to form a uniform contact surface with the heat dissipation layer 700 compared to the BB type cooling fin 600 having a round shape, so for effective heat dissipation of the battery cells 110, it is preferable to provide the cooling fin 600 in a round shape.

[0159] Meanwhile, although not specifically mentioned above, the cooling fin 600 according to an embodiment of the present invention may be installed within a battery module or a battery pack.

[0160] A battery module according to an embodiment of the present invention includes a battery cell stack consisting of a plurality of battery cells and a module frame that houses the battery cell stack. A cooling member 500 may be provided between the module frame and the battery cell stack, and cooling fins 600 may be provided between the battery cells.

[0161] Battery packs according to embodiments of the present invention may be provided in a variety of forms.

[0162] As an example, a battery pack according to an embodiment of the present invention may include at least one of the battery modules described above. The battery pack according to an embodiment of the present invention may include a pack frame and at least one battery module mounted in the pack frame, and the battery module may include a battery cell stack, a module frame, a cooling member 500 located between the battery cell stack and the module frame, and cooling fins 600 provided between adjacent battery cells.

[0163] As another example, a battery pack according to an embodiment of the present invention may include a battery cell stack and a pack frame that houses the battery cell stack, with a cooling member 500 being provided between the battery cell stack and the pack frame, and cooling fins 600 being provided between adjacent battery cells.

[0164] Here, the battery cell stack may be provided in a module-less structure that is not sealed by a module frame, etc. The battery cell stack may be provided in an open structure. In this case, the battery cell stack is provided in a state where its outer shape is maintained by fixing members such as side plates or holding straps, and such a type of battery cell stack is called a cell block.

[0165] Typically, a battery pack may be formed in 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. At this time, since the battery module includes a module frame forming its outer surface, the conventional battery cells are doubly protected by the module frame of the battery module and the pack frame of the battery pack. However, such a double assembly structure not only increases the manufacturing cost and manufacturing process of the battery pack, but also has the disadvantage of reducing reassembly when some battery cells are defective. In addition, when a cooling member, which is a cooling member, is present outside the battery module, there is a problem that the heat transfer path between the battery cells and the cooling member becomes somewhat complicated. Therefore, the battery cell stack of the present embodiment is provided in a structure that is not sealed by the module frame, and may be directly coupled to the pack frame of the battery pack. As a result, the structure of the battery pack is simplified, advantages in terms of manufacturing cost and manufacturing process can be obtained, and the weight of the battery pack can be reduced. Also, since the battery cell stack is provided in a module-less structure, the battery cell stack can be positioned closer to the cooling member 500 in the pack frame, making it easier to achieve heat dissipation by the cooling member 500.

[0166] Meanwhile, although not specifically mentioned above, the battery pack according to an embodiment of the present invention may additionally include a Battery Management System (BMS) for managing the temperature, voltage, etc. of the battery and / or a cooling unit.

[0167] 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.

[0168] 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]

[0169] 100 Battery Module 110 Battery Cell 120 Battery cell stack 130 Side Plate 140 Retaining Strap 150 Busbar Frame 200 Pack Frames 300 Resin layer 400 End Plate 500 Heatsink 600 Cooling Fins 700 Heat dissipation layer

Claims

1. a battery module including a battery cell stack in which a plurality of battery cells are stacked; A pack frame that houses the battery module; and a heat sink located between the battery cell stack and the pack frame; A cooling fin is disposed between two adjacent battery cells; the cooling fin includes a body portion that contacts the battery cells and an extension portion that extends above the battery cell stack (z-axis) and is positioned adjacent to the heat sink; The battery pack has a bent portion formed by bending the extension portion in a direction different from the upper side (z-axis), and has a rounded shape curved to have a curvature at a portion in contact with the heat sink or a heat dissipation layer provided on the heat sink.

2. the heat sink is located outside the battery module; The battery pack of claim 1 , wherein the extension contacts the heat sink.

3. The battery pack according to claim 1 , wherein the bent portion formed in the extension portion has an L-shaped spring shape or an S-shaped spring shape.

4. The battery pack according to claim 1 , wherein the cooling fin is made of an elastic material.

5. The battery pack according to claim 1 , wherein the bent portion is deformable according to a distance between the battery cell stack and the heat sink.

6. The battery pack according to claim 1 or 2, further comprising a heat dissipation layer formed between the battery cell stack and the heat sink.

7. The battery pack according to claim 6 , wherein the heat dissipation layer is discontinuously positioned in a stacking direction of the battery cell stack.

8. The cooling fins are two or more in number, and the two or more cooling fins are spaced apart; The battery pack according to claim 6 , wherein the heat dissipation layer is formed in a plurality of pieces corresponding to the two or more cooling fins, respectively.

9. The battery pack of claim 6 , wherein the heat dissipation layer is in contact with the extension.

10. The battery pack of claim 6 , wherein the heat dissipation layer is located closer to a second point, which is an end of the extension portion, than to a first point where the body and the extension portion abut against each other.

11. The battery pack of claim 6 , wherein the heat dissipation layer contacts the extension and the heat sink.

12. The battery pack of claim 1 or 2, wherein the battery module includes a side plate in contact with an outermost battery cell of the battery cell stack.

13. The side plates are at least two in number, The battery cell stack is disposed between the two side plates; 13. The battery pack of claim 12, wherein the relative positions of the two side plates and the battery cell stack are fixed by retaining straps.

14. The retaining strap includes a locking tab formed at an end in a longitudinal direction thereof, The battery pack according to claim 13 , wherein the side plate is formed with a locking groove corresponding to the locking claw.

15. A device comprising at least one battery pack according to claim 1 or 2.

16. In the cooling fins that form a heat transfer path between the battery cell and the heat sink, a main body portion positioned parallel to the battery cell and an extension portion extending from one end of the main body portion toward the heat sink; A cooling fin, wherein the extension portion has a bent portion formed by bending in a direction different from the direction in which the main body portion extends, and has a rounded shape curved to have a curvature at the portion in contact with the heat sink or a heat dissipation layer provided on the heat sink.

17. The cooling fin of claim 16 , wherein the extension includes a first point having a first curvature and a second point having a second curvature, the first curvature and the second curvature being different from one another.

18. The cooling fin of claim 16 or 17, wherein the extension portion includes a first point having a first inclination and a second point having a second inclination, the first inclination and the second inclination being different from each other.

19. A cooling fin forming a heat transfer path between a battery cell and a heat sink, a main body portion positioned parallel to the battery cell and an extension portion extending from one end of the main body portion toward the heat sink; The extension portion has a round shape curved to have a curvature, the extension portion includes a first point having a first slope and a second point having a second slope, the first slope and the second slope being different from each other; A cooling fin, wherein on a cross section of the extension portion, an absolute value of the first slope is smaller than an absolute value of the second slope, and the first point is located farther from one end of the main body portion than the second point.

20. The cooling fin of claim 18 , wherein the first point is located closer to the heat sink than the second point.

21. The cooling fin of claim 18 , wherein the second point is out of contact with the heat sink.

22. The cooling fin according to claim 16 or 17, wherein the extension portion is deformable according to a distance between the battery cell and the heat sink.

23. The cooling fin according to claim 16 or 17, wherein a plurality of the extensions are formed on one cooling fin.

24. The cooling fin according to claim 16 or 17, wherein a heat dissipation layer is located between the heat sink and a battery cell stack in which a plurality of the battery cells are stacked, and the extension portion is in contact with the heat dissipation layer.

25. The heat dissipation layer is formed in a plurality of pieces, The extension portion is formed in a plurality of pieces on one cooling fin, The cooling fin of claim 24 , wherein the plurality of heat dissipation layers respectively correspond to a plurality of extensions formed on one cooling fin.

26. The cooling fin according to claim 24 , wherein the heat dissipation layer is positioned discontinuously in a stacking direction of the battery cell stack.

27. The cooling fins are two or more in number, and the two or more cooling fins are spaced apart; The cooling fin according to claim 24 , wherein the heat dissipation layer is formed in a plurality of pieces corresponding to the two or more cooling fins, respectively.

28. The cooling fin of claim 24 , wherein the heat dissipation layer contacts the extension and the heat sink.

29. A battery module comprising at least one cooling fin according to claim 16 or 17.

30. A battery pack comprising at least one cooling fin according to claim 16 or 17.

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