Endothermic pad for secondary battery and battery pack including same

Abstract

Provided is an endothermic pad for a secondary battery, comprising: a pouch having an inner space; and an endothermic material accommodated in the inner space, wherein the pouch comprises a bent portion processed by a forming process so as to define the inner space, and the bent portion maintains a bent state when no external force is applied from the outside of the pouch.

Description

Heat-absorbing pad for secondary battery and battery pack including the same

[0001] The present invention relates to a heat-absorbing pad for a secondary battery and a battery pack including the same, and more particularly, to a heat-absorbing pad for a secondary battery having excellent heat-absorbing efficiency and contributing to improved energy density, and a battery pack including the same.

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0008631, filed January 19, 2024, the entire disclosure of which is incorporated herein by reference.

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. They are widely used as a power source for various wireless devices, including handsets, laptops, and cordless vacuum cleaners. Recently, improved energy density and economies of scale have dramatically reduced the per-unit manufacturing cost of secondary batteries. Furthermore, as the range of battery electric vehicles (BEVs) has increased to match that of fuel-powered vehicles, the primary use of secondary batteries is shifting from mobile devices to mobility.

[0004] Meanwhile, demand for large-capacity battery packs for electric vehicles and other applications is increasing. Large-capacity battery packs installed in automobiles are expected to increase capacity and enhance safety.

[0005] The first technical task to be achieved by the present invention is to provide a heat absorption pad for a secondary battery that has excellent heat absorption efficiency and can contribute to improving energy density.

[0006] The second technical task to be achieved by the present invention is to provide a battery pack having excellent heat absorption efficiency and contributing to improved energy density.

[0007] The present invention provides a heat absorbing pad for a secondary battery, which comprises a pouch having an internal space and an absorbing material accommodated in the internal space, in order to achieve the first technical task, wherein the pouch includes a bent portion processed by a forming process to define the internal space, and the bent portion maintains a bent state when no external force is applied from outside the pouch.

[0008] In some embodiments, the pouch may include folds having corresponding shapes in each of the first layer and the second layer.

[0009] In some embodiments, the pouch comprises a first layer and a second layer facing each other while defining the interior space, and the first layer and the second layer can extend at least partially from each other at the bend while maintaining a constant distance from each other.

[0010] In some embodiments, the secondary battery heat-absorbing pad further includes a superabsorbent resin, and the heat-absorbing material may be absorbed into the superabsorbent resin.

[0011] In some embodiments, the superabsorbent resin may be in a powder state and the heat-absorbing material may be water.

[0012] In some embodiments, the pouch includes a first layer and a second layer facing each other while defining the interior space, and the pouch may include a pattern of the folds repeated a plurality of times at predetermined intervals in at least one of the first layer and the second layer.

[0013] In order to achieve the second technical task, the present invention provides a battery pack comprising: a plurality of battery cells arranged in a first direction in a vertical coordinate system defined by a first direction, a second direction, and a third direction that are perpendicular to each other; at least one heat-absorbing pad arranged between the plurality of battery cells; and a pack housing that accommodates the plurality of battery cells, wherein the heat-absorbing pad comprises: a pouch including a bending portion corresponding to at least a portion of an outer shape of the battery cell; and a superabsorbent resin and a heat-absorbing material absorbed in the superabsorbent resin.

[0014] In some embodiments, the heat-absorbing pad may be provided between two adjacent battery cells.

[0015] In some embodiments, the folded portion of the pouch can maintain a folded state when no external force is applied by the battery cells.

[0016] In some embodiments, the heat-absorbing pad is provided between the battery cell and the pack housing, the heat-absorbing pad includes a bend corresponding to the shape of the battery cell and the pack housing, and the bend can maintain a bend state when no external force is applied by the battery cell and the pack housing.

[0017] In some embodiments, the pouch comprises a first layer and a second layer facing each other while defining the interior space, and the first layer and the second layer can extend at least partially from each other at the bend while maintaining a constant distance from each other.

[0018] In some embodiments, the central portion of the first layer may be formed to be convex compared to the outer edge of the first layer, and the entire central portion and outer edge of the first layer may be folded.

[0019] The heat absorption pad of the present invention has an outer shape corresponding to the complex shape of the cooling target, thereby having excellent heat absorption efficiency and contributing to improving energy density by increasing internal space efficiency.

[0020] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from practicing the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0021] FIG. 1 is a perspective view of a battery pack according to exemplary embodiments of the present invention.

[0022] FIG. 2 is a perspective view illustrating some elements of a battery pack according to exemplary embodiments of the present invention.

[0023] Fig. 3 is a side cross-sectional view showing a cross-section of the heat-absorbing pad cut along line III-III' of Fig. 1.

[0024] FIG. 4 is an enlarged perspective view showing battery cells mounted within a lower case according to one embodiment of the present invention.

[0025] Figure 5 is a schematic cross-sectional view showing the above-described heat-absorbing pad inserted between battery cells.

[0026] Fig. 6 is a cross-sectional side view showing the heat-absorbing pad of Fig. 5 without contact with the battery cells.

[0027] Figure 7 is a perspective view showing a heat absorbing pad according to one embodiment of the present invention.

[0028] Fig. 8 is a cross-sectional view showing the cross-section of the heat-absorbing pad of Fig. 7 taken along line VIII-VIII'.

[0029] Figure 9 is a perspective view showing a heat absorbing pad according to another embodiment of the present invention.

[0030] Fig. 10 is a cross-sectional view showing the cross-section of the heat-absorbing pad of Fig. 9 taken along line XX'.

[0031] Fig. 11 is a side view schematically showing an electrified vehicle according to one embodiment of the present invention.

[0032] Figure 12 is a schematic diagram conceptually showing the battery pack and other components mounted on the electric vehicle.

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention may be modified in various different forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. It is preferable to interpret that the embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art. Like numbers refer to like elements throughout. Furthermore, various elements and areas in the drawings are schematically drawn. Therefore, the present invention is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0034] While terms like "first" and "second" may be used to describe various components, these components are not limited by these terms. These terms are used solely to distinguish one component from another. For example, a first component could be referred to as a "second component," and vice versa, without departing from the scope of the present invention.

[0035] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the inventive concept. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the expressions "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, operations, components, parts, or combinations thereof.

[0036] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Furthermore, it is to be understood that commonly used terms, such as those defined in dictionaries, should be interpreted to have a meaning consistent with their meaning within the relevant technical context, and should not be interpreted in an overly formal sense unless explicitly defined herein.

[0037] In some embodiments, where implementations are otherwise feasible, specific process sequences may be performed in a different order than described. For example, two processes described in succession may be performed substantially simultaneously, or in a reverse order from the described order.

[0038] In the accompanying drawings, variations in the shapes depicted may be expected, for example, depending on manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as being limited to the specific shapes of the regions depicted herein, but should include, for example, changes in shapes resulting from the manufacturing process. All terms "and / or" used herein include each and every combination of one or more of the mentioned components. In addition, the term "substrate" used herein may mean the substrate itself, or a laminated structure including the substrate and a predetermined layer or film formed on the surface thereof. In addition, the "surface of the substrate" in this specification may mean the exposed surface of the substrate itself, or the outer surface of a predetermined layer or film formed on the substrate.

[0039]

[0040] (Example 1)

[0041] FIG. 1 is a perspective view of a battery pack (100) according to exemplary embodiments of the present invention.

[0042] FIG. 2 is a perspective view showing some elements of a battery pack (100) according to exemplary embodiments of the present invention.

[0043] In FIGS. 1 and 2, the battery pack (100) is illustrated as being defined in a vertical coordinate system defined by a first direction along the X-axis, a second direction along the Y-axis, and a third direction along the Z-axis while being perpendicular to each other, but the first direction, the second direction, and the third direction are not particularly limited as long as they are relatively perpendicular to each other.

[0044] Referring to FIGS. 1 and 2, a battery pack (100) may include a lower case (110), battery cells (120), a center beam (130), a cross beam (116), a plurality of exhaust devices (140), a plurality of first embedded guides (151), a plurality of second embedded guides (153), a pack gasket (160), and an upper case (170). The battery pack (100) may be a final form of a battery system mounted on a mobility device, etc. Hereinafter, a secondary battery may refer to any battery cell capable of charging and discharging.

[0045] The pack housing (101) defining the appearance of the battery pack (110) may include the lower case (110) and the upper case (170).

[0046] The lower case (110) may provide a receiving space (119) for mounting a plurality of battery cells (120). In some embodiments, the lower case (110) may include a plate portion (110P) and a side wall (110S). Two directions substantially parallel to the plate portion (110P) are defined as a first direction (e.g., an X-axis direction) and a second direction (e.g., a Y-axis direction), and a direction substantially perpendicular to the plate portion (110P) of the housing (110) is defined as a third direction (e.g., a Z-axis direction). Each of the X-axis direction, the Y-axis direction, and the Z-axis direction may be substantially perpendicular to each other. Unless otherwise stated, the definitions of directions are the same for the drawings below.

[0047] A plurality of battery cells (120) may be arranged on a plate portion (110P) of a lower case (110). The plate portion (110P) may support the plurality of battery cells (120). The plate portion (110P) may include an upper surface and a lower surface that are substantially parallel. The upper surface of the plate portion (110P) may face the plurality of battery cells (120). The lower surface of the plate portion (110P) is the opposite surface of the upper surface of the plate portion (110P).

[0048] The side wall (110S) can horizontally surround a plurality of battery cells (120). The side wall (110S) can protect the plurality of battery cells (120) in a lateral direction. The side wall (110S) can include a first side wall (111), a second side wall (112), a third side wall (113), and a fourth side wall (114). The first to fourth side walls (111, 112, 113, 114) can be fixed to each other by a method such as friction stir welding, spot welding, etc., and are not particularly limited thereto.

[0049] The first and second side walls (111, 112) may be substantially perpendicular to the second direction (e.g., the Y-axis direction). The third and fourth side walls (113, 114) may each be substantially perpendicular to the first direction (e.g., the X-axis direction). In some embodiments, the first and second side walls (111, 112) may cover a side surface of the plate portion (110P). In some embodiments, the third and fourth side walls (113, 114) may be disposed on the plate portion (110P).

[0050] In some embodiments, the first to fourth side walls (111, 112, 113, 114) may be provided by an extrusion process. According to exemplary embodiments, the first to fourth side walls (111, 112, 113, 114) may include an internal empty space, and thus the side wall (110S) may be lightweight. According to exemplary embodiments, the empty space of the first to fourth side walls (111, 112, 113, 114) may be either a venting path for a gas or a channel for a coolant.

[0051] Hereinafter, the technical concept of the present invention will be described with reference to an embodiment in which each of the plurality of battery cells (120) does not include a module frame. However, this is a non-limiting example and does not limit the technical concept of the present invention in any way. Those skilled in the art will readily understand battery packs that employ battery modules that include a module frame that exposes one edge of the battery cells, based on the description herein.

[0052] In some embodiments, the receiving space (119) may be partitioned into two or more partition spaces (119d) by one or more partition beams (130, 116). The partition beams (130, 116) may include a center beam (130). In some embodiments, the partition beams (130, 116) may include one or more cross beams (116).

[0053] The center beam (130) can isolate elements mounted on the lower case (110) from each other. Accordingly, the center beam (130) can protect a plurality of battery cells (120) while preventing unwanted short circuits between them.

[0054] A center beam (130) may extend between the third and fourth side walls (113, 114). The center beam (130) may extend in a first direction (e.g., in the X-axis direction). The center beam (130) may contact the third side wall (113) and the fourth side wall (114). The center beam (130) may isolate the plurality of battery cells (120) from each other. The center beam (130) may be interposed between the plurality of battery cells (120). In some embodiments, the center beam (130) may divide the receiving space (119) into two regions in a second direction (e.g., in the Y-axis direction).

[0055] In some embodiments, the cross beam (116) may be provided to divide the receiving space (119) into two or more regions in a first direction (e.g., X-axis direction). The cross beam (116) may further isolate elements isolated by the center beam (130).

[0056] Some cross beams (116) may extend in a second direction (e.g., in the Y-axis direction) between the center beam (130) and the first side wall (111). Other cross beams (116) may extend in a second direction (e.g., in the Y-axis direction) between the center beam (130) and the second side wall (112). In some embodiments, the cross beams (116) may be provided to define a space in which a single battery cell stack or a group of battery cells are accommodated.

[0057] The arrangement of the center beam (130), cross beam (116), and multiple battery cells (120) disclosed in FIG. 1 is a non-limiting example and does not limit the technical concept of the present invention in any way. One of ordinary skill in the art will readily be able to arrive at a battery pack comprising various arrangements and numbers of center beams and battery cells based on the description herein.

[0058] In some embodiments, a plurality of exhaust devices (140) may be coupled to the fourth side wall (114). The fourth side wall (114) may include a plurality of exhaust holes connected to the plurality of exhaust devices (140). The plurality of exhaust holes may be configured to provide a path for exhausting gases and heat within the battery pack (100).

[0059] The plurality of exhaust devices (140) may be configured to delay thermal propagation by releasing high temperature gas inside the battery pack (100) to the outside when at least one of the plurality of battery cells (120) is in a thermal runway state.

[0060] Here, thermal runaway of multiple battery cells (120) is a state in which temperature changes in multiple battery cells (120) further accelerate the temperature change, which is an uncontrollable positive feedback. Multiple battery cells (120) in a state of thermal runaway exhibit a rapid temperature increase and can emit a large amount of high-pressure gas and combustion debris.

[0061] In some embodiments, a plurality of first embedding guides (151) may be disposed on the side wall (110S). The plurality of first embedding guides (151) may be disposed on corners (110C) of the upper surface of the side wall (110S). The plurality of first embedding guides (151) may be coupled to the corners (110C) of the upper surface of the side wall (110S). The plurality of first embedding guides (151) may be partially embedded in the side wall (110S). The plurality of first embedding guides (151) may partially protrude from the side wall (110S).

[0062] In some embodiments, a plurality of second embedding guides (153) may be disposed on the side wall (110S). The plurality of second embedding guides (153) may be disposed on the upper surface of the side wall (110S). The plurality of second embedding guides (153) may be interposed between corners (110C) of the side wall (110S). The plurality of second embedding guides (153) may be interposed between the plurality of first embedding guides (151). The plurality of second embedding guides (153) may be coupled to the upper surface of the side wall (110S). The plurality of second embedding guides (153) may be partially embedded in the side wall (110S). The plurality of second embedding guides (153) may partially protrude from the side wall (110S).

[0063] In some embodiments, each of the plurality of first and second embedding guides (151, 153) may comprise a metallic material. Each of the plurality of first and second embedding guides (151, 153) may comprise, for example, aluminum. Each of the plurality of first and second embedding guides (151, 153) may also comprise, for example, steel, such as carbon steel, nickel steel, chromium steel, nickel-chromium steel, and manganese steel.

[0064] The battery pack (100) may further include electrical components. In some embodiments, the electrical components may be mounted on the lower case (110). In some embodiments, the electrical components may be positioned between the fourth side wall (114) where the exhaust devices (140) are installed and the plurality of battery cells (120). In some embodiments, the electrical components may include any electronic components necessary to operate the battery pack.

[0065] In some embodiments, the electrical components may include, for example, a battery management system (BMS). The BMS may be configured to monitor, balance, and control the battery pack. In some embodiments, monitoring the battery pack (100) may include measuring the voltage and current of a specific battery cell among a plurality of battery cells (120) and measuring the temperature of set locations within the battery pack (100). In some embodiments, the battery pack (100) may include measuring instruments for measuring the voltage, current, and temperature described above.

[0066] Balancing of the battery pack (100) is an operation to reduce the deviation between the plurality of battery cells (120). Control of the battery pack (100) includes preventing the occurrence of overcharge, overdischarge, and overcurrent. Through monitoring, balancing, and control, the battery pack (100) can operate under optimal conditions, thereby preventing or reducing the shortening of the lifespan of each of the plurality of battery cells (120).

[0067] The above-described electrical components may further include a cooling device, a PRA (power relay assembly), a safety plug, etc. The cooling device may include a cooling fan. The cooling fan may prevent overheating of each of the plurality of battery cells (120) by circulating air inside the battery pack (100). The PRA may be configured to supply or cut off power from the high-voltage battery to an external load (e.g., a motor of a vehicle). The PRA may protect the plurality of battery cells (120) and the external load (e.g., a motor of a vehicle) by cutting off power supply to the external load (e.g., a motor of a vehicle) in a situation where an abnormal voltage, such as a voltage surge, occurs.

[0068] The battery pack (100) may further include a plurality of bus bars configured to electrically connect a plurality of battery cells (120). The plurality of battery cells (120) may be connected in series and / or in parallel by the plurality of bus bars. Accordingly, the battery pack (100) may be configured to output a high voltage to an external load (e.g., a vehicle motor).

[0069] The gasket (160) may include a material that is elastic in response to applied pressure. The gasket (160) may include, for example, rubber synthesized from a material such as EPDM (ethylene-propylene diene monomer). When the lower case (110) and the upper case (170) are coupled, the gasket (160) may be interposed between the lower case (110) and the upper case (170). The lower case (110) and the upper case (170) may pressurize the gasket (160) so that a certain amount of deformation occurs in the gasket (160). Accordingly, the battery pack (100) may be sealed, and external fluid may be blocked from the internal space of the battery pack (100).

[0070] The upper case (170) may be coupled to the lower case (110) to cover the receiving space (119). In some embodiments, the upper case (170) may include a main surface and an edge portion. The main surface may cover elements mounted in the battery pack (100), such as a plurality of battery cells (120) and electrical components. The edge portion is a surface that comes into contact with the lower case (110). In some embodiments, the upper case (170) may have a flat shape, in which case the edge portion may horizontally surround the main surface. In some embodiments, the main surface may be elevated relative to the edge portion, and the edge portion and the main surface may be connected by a curved portion.

[0071] In some embodiments, the upper case (170) may be coupled to a side wall (110S) of the lower case (110) by a plurality of first and second embedding guides (151, 153). According to exemplary embodiments, the battery pack (100) may further include elements coupled to the plurality of first and second embedding guides (151, 153) to secure the upper case (170) to the side wall (110S) of the lower case (110). The elements may include, but are not limited to, bolts and nuts.

[0072] The above battery pack (100) may further include a heat-absorbing pad (180). FIG. 3 is a side cross-sectional view showing a cross-section of the heat-absorbing pad (180) taken along line III-III' of FIG. 1.

[0073] Referring to FIGS. 1 and 3, the heat absorbing pad (180) may be configured to absorb heat generated from the battery cells (120) and / or block or delay the transfer of the heat.

[0074] In some embodiments, the heat absorbing pad (180) may be provided on top of the battery cells (120). In some embodiments, the heat absorbing pad (180) may be provided between the upper case (170) and the battery cells (120).

[0075] The above-described heat-absorbing pad (180) may have a predetermined area along a plane perpendicular to a third direction (e.g., the Z-axis direction). The heat-absorbing pad (180) may include a laminate sheet (180c) having an internal space. The laminate sheet (180c) may constitute an outer appearance of the heat-absorbing pad (180). In some embodiments, the heat-absorbing pad (180) may include an absorbent member (180p) and a heat-absorbing material provided in the internal space of the laminate sheet (180c). The laminate sheet (180c) may include a first layer (180a) and a second layer (180b) that are generally parallel, and the internal space may be defined between the first layer (180a) and the second layer (180b).

[0076] The above laminate sheet (180c) may be formed of a single layer or may be a laminate in which two or more layers are laminated. In some embodiments, the laminate sheet (180c) may include a multilayer structure in which an outermost outer resin layer made of an insulating material such as polyethylene terephthalate (PET) or nylon, a metal layer made of aluminum that maintains mechanical strength and prevents the penetration of moisture and oxygen, and an inner resin layer made of a polyolefin-based material that has heat-adhesive properties and acts as a sealant are laminated.

[0077] The above-mentioned heat-absorbing material may be absorbed into the absorbent member (180p) and may be a material that can undergo phase change according to temperature changes. The above-mentioned laminate sheet (180c) may be configured to be deformable according to the phase change of the heat-absorbing material.

[0078] In some embodiments, the absorbent member (180p) may include an absorbent polymer such as a super absorbent polymer (SAP). Any material known in the art may be used as the super absorbent polymer, and is not particularly limited thereto. In some embodiments, the super absorbent polymer may include polyacrylamide, polyacrylic acid, polymethacrylic acid, polyethylene oxide, polyvinyl alcohol, gelatin, polysaccharide, chitosan, sodium carboxymethyl cellulose, or a combination thereof, but the present invention is not limited thereto. In some embodiments, the absorbent member (180p) may have a form such as a powder, granules, pellets, platelets, or slabs, and is not particularly limited thereto.

[0079] The absorbent member (180p) may have a liquid heat-absorbing material absorbed therein. In some embodiments, the heat-absorbing material may include a material that can repeatedly vaporize and condense within the operating temperature range of the battery cells (120) and within a pressure range within and outside of atmospheric pressure. For example, the heat-absorbing material may include a material that can vaporize or condense within a pressure range of about 1 atm to about 10 atm and a temperature of about 70°C to about 130°C.

[0080] In some embodiments, the heat-absorbing material may include water, ethanol, isopropyl alcohol, or the like. The heat-absorbing material may be absorbed in the absorbent member (180p) when in a liquid state. The heat-absorbing material may be vaporized by heat transferred from the battery cells (120) through the second layer (180b) of the laminate sheet (180c). The vaporized heat-absorbing material may exist in a gaseous state in the laminate sheet (180c) and may be condensed and liquefied as it cools, and may be reabsorbed in the absorbent member (180p). Since the heat transferred from the battery cells (120) is used as a temperature increase and enthalpy of vaporization of the heat-absorbing material, the transfer of the heat to other neighboring battery cells (120) may be reduced or blocked.

[0081] The above-described heat-absorbing pad (180) may include a folded portion (180f). The folded portion (180f) may be formed by a forming process. The forming process may be a process of forming the laminate sheet (180c) by applying pressure so that the laminate sheet (180c) has a desired shape. The laminate sheet (180c) may be formed into an at least partially folded shape by the forming process.

[0082] As shown in FIG. 3, the bending portion (180f) can maintain a bent state even when no external force is applied. In other words, the bending state can be maintained even when no external force is applied to the heat-absorbing pad (180) by the upper case (170) and the battery cells (120). However, the bending state when no external force is applied to the heat-absorbing pad (180) does not need to be completely identical to the bending state when the heat-absorbing pad (180) is interposed between the upper case (170) and the battery cells (120) and assembled. In some embodiments, the bending state when no external force is applied to the heat-absorbing pad (180) may be somewhat deformed when the heat-absorbing pad (180) is interposed between the upper case (170) and the battery cells (120), but the overall bending state of the heat-absorbing pad (180) can be generally maintained.

[0083] In some embodiments, the bending portion (180f) may be provided only in the first layer (180a). In some embodiments, the bending portion (180f) may be provided only in the second layer (180b). In some embodiments, the bending portion (180f) may be provided in both the first layer (180a) and the second layer (180b).

[0084] In some embodiments, the bending portion (180f) may be provided in the first layer (180a) and the second layer (180b), and the bending portion of the first layer (180a) and the bending portion of the second layer (180b) may have corresponding shapes. Here, the term "corresponding shapes" means that the degree of bending may be somewhat different, but the bent shape and / or direction are the same or similar.

[0085] In some embodiments, the bent portion of the first layer (180a) and the bent portion of the second layer (180b) may extend at least partially while maintaining a constant distance from each other. As illustrated in FIG. 3, each of the first layer (180a) and the second layer (180b) includes a portion extending generally in the Z-axis direction and a planar portion bent therefrom and extending in a direction perpendicular to the Z-axis direction.

[0086] In some embodiments, the laminate sheet (180c) may include a pattern of folds (180f) that are repeated multiple times at predetermined intervals. In the embodiment illustrated in FIGS. 1 and 3, the laminate sheet (180c) includes a pattern of folds (180f) that are repeated three times in the X-axis direction and twice in the Y-axis direction.

[0087] In some embodiments, the thermal pad (180) may have a bonding portion (180m). In some embodiments, the bonding portion (180m) may be a portion formed by fusing facing laminate sheets of the thermal pad (180) (i.e., the first layer (180a) and the second layer (180b)). In some embodiments, the thermal pad (180) may be configured such that the bonding portion (180m) is opened or a specific location of the bonding portion (180m) is opened when a thermal event occurs inside.

[0088] As illustrated in FIG. 1, when a heat-absorbing pad (180) is placed between the upper surface of the battery cells (120) and the upper case (170), even if a thermal event occurs in a specific battery cell (120), flame energy can be effectively weakened and the upper case (170) can be mitigated or prevented from being damaged by heat.

[0089]

[0090] FIG. 4 is an enlarged perspective view showing battery cells (120) mounted in a lower case (110) according to one embodiment of the present invention.

[0091] Referring to FIG. 4, battery cell stacks (S1, S2, . . . , S6) are arranged within each region defined by each of the side walls (111, 112, 113, 114) of the lower case (110), the center beam (130), and the cross beam (116). Each of the battery cell stacks (S1, S2, . . . , S6) includes a plurality of battery cells (120). Hereinafter, a battery cell stack may simply mean a collection of a plurality of battery cells, or may mean an assembly that accommodates a plurality of battery cells within a specific frame.

[0092] In some embodiments, the battery cells (120) may be pouch-shaped battery cells, but the present invention is not limited thereto. In some embodiments, the battery cells (120) may be cylindrical battery cells or square battery cells.

[0093] In some embodiments, the battery cells (120) may have a thin plate-shaped body and may be configured as a pouch cell structure. The pouch cell may include an electrode assembly in which a positive electrode, a separator, and a negative electrode are alternately laminated within a pouch made of a laminate sheet. An electrode tab may be drawn out from at least one side of the electrode assembly and connected to a cell lead. The positive and negative electrodes may be manufactured by applying a slurry of an electrode active material, a binder resin, a conductive agent, and other additives to at least one surface of a current collector. For the positive electrode, a typical positive electrode active material such as a lithium-containing transition metal oxide may be used, and for the negative electrode, a typical negative electrode active material such as lithium metal, carbon material, and metal compound or a mixture thereof capable of absorbing and releasing lithium ions may be used. In addition, a typical porous polymer film used in a lithium secondary battery may be employed as the separator.

[0094] As the electrolyte accommodated in the pouch together with the electrode assembly, a typical lithium secondary battery electrolyte may be employed. The pouch is formed of a sheet material and has a receiving portion for accommodating the electrode assembly. The sheet material constituting the pouch may include a multilayer structure in which an outermost outer resin layer made of an insulating material such as polyethylene terephthalate (PET) or nylon, a metal layer made of aluminum that maintains mechanical strength and prevents the penetration of moisture and oxygen, and an inner resin layer made of a polyolefin-based material that has thermal adhesive properties and serves as a sealant are laminated.

[0095] The sheet material forming the above pouch may have a predetermined adhesive resin layer interposed between the inner resin layer and the metal layer, and between the outer resin layer and the metal layer, as needed. The adhesive resin layer is formed as a single layer or multiple layers for smooth adhesion between different materials, and the material is typically a polyolefin resin, or a polyurethane resin may be used for smooth processing, and a mixture of these may also be employed.

[0096] The plurality of battery cells (120) may be arranged in a first direction (e.g., X-axis direction). In some embodiments, the first battery cell stack (S1), the second battery cell stack (S2), and the third battery cell stack (S3) may be arranged in the first direction (e.g., X-axis direction). In some embodiments, the fourth battery cell stack (S4), the fifth battery cell stack (S5), and the sixth battery cell stack (S6) may be arranged in the first direction (e.g., X-axis direction).

[0097] In some embodiments, the first battery cell stack (S1) and the fourth battery cell stack (S4) may be arranged in a second direction (e.g., in the Y-axis direction). In some embodiments, the second battery cell stack (S2) and the fifth battery cell stack (S5) may be arranged in a second direction (e.g., in the Y-axis direction). In some embodiments, the third battery cell stack (S3) and the sixth battery cell stack (S6) may be arranged in a second direction (e.g., in the Y-axis direction).

[0098]

[0099] Fig. 5 is a schematic side cross-sectional view showing the above-described heat-absorbing pad (181) inserted between battery cells (120). The side cross-section shown in Fig. 5 is, for example, a cross-section cut along line VV' of Fig. 4.

[0100] Referring to FIGS. 4 and 5, the heat-absorbing pad (181) may have a shape that extends in a second direction (e.g., Y-axis direction), which is generally the longitudinal direction of the battery cells (120). In some embodiments, the heat-absorbing pad (181) extends in the second direction (e.g., Y-axis direction) and may be in direct contact with a side surface of an adjacent battery cell (120).

[0101] The above-described heat-absorbing pad (181) may have a predetermined area along a plane perpendicular to a first direction (e.g., X-axis direction). In some embodiments, the heat-absorbing pad (181) may be interposed between a pair of battery cells (120). A first side surface (181a) forming one side of the heat-absorbing pad (181) may be in direct contact with one of the battery cells (120) of the pair of battery cells. In addition, a second side surface (181b) forming the other side of the heat-absorbing pad (181) may be in direct contact with the remaining one of the battery cells (120) of the pair of battery cells.

[0102] In some embodiments, the side surfaces of the battery cells (120) may include curved portions. As illustrated in FIG. 5, the side surfaces (181a, 181b) of the heat-absorbing pad (181) facing the battery cells (120) may have a folded portion (181f) corresponding to the curved portions of the side surfaces of the battery cells (120).

[0103] Fig. 6 is a cross-sectional view showing a state in which the heat-absorbing pad (181) of Fig. 5 is not in contact with the battery cells (120).

[0104] Referring to Fig. 6, the bending state of the bending portion (181f) of the heat-absorbing pad (181) can be generally maintained even when not in contact with the battery cells (120). Although there may be some deformation in the shape of the bending portion (181f) when the heat-absorbing pad (181) is in close contact with the neighboring battery cells (120) and when it is spaced apart from the battery cells (120), the bending state of the bending portion (181f) can be generally maintained.

[0105] Referring back to FIG. 5, in some embodiments, the heat absorbing pad (181) may be thermally connected to the lower case (110) and may transfer heat received from the battery cells (120) to the plate portion (110P). In some embodiments, the heat absorbing pad (181) may be thermally connected to the upper case (170) and / or the heat absorbing pad (180) (see FIG. 1). Here, the fact that the heat absorbing pad (181) is 'thermally connected' to an object may mean that most of the heat emitted from the heat absorbing pad (181) is removed through the object, for example, more than 50% of the heat emitted from the heat absorbing pad (181) is removed through the object.

[0106] In some embodiments, the plate portion (110P) of the lower case (110) may include a heat sink (110FP). For example, the heat sink (110FP) may include a passage configured to allow a cooling fluid to flow therein. Accordingly, heat transferred to the lower plate portion (110P) through the heat absorption pad (181) may be smoothly removed by the cooling fluid flowing through the heat sink (110FP). To this end, the heat absorption pad (181) may be arranged closer to the lower case (110) than to the upper case (170).

[0107] In some embodiments, the heat-absorbing pads (181) may be arranged alternately with the battery cells (120). In some embodiments, the heat-absorbing pads (181) may be provided one by one for each of two or more battery cells (120). That is, two or more battery cells (120) may be arranged between two closest adjacent heat-absorbing pads (181).

[0108] In some embodiments, the heat absorption pad (181) may be provided at both ends of a plurality of battery cells (120) provided in one compartment space (119d) in the first direction (e.g., X-axis direction). In this case, a thermal event occurring in one compartment space (119d) may be effectively prevented or delayed from being transferred to another adjacent compartment space (119d). In this case, the heat absorption pad (181) may be arranged to directly face the cross beam (116).

[0109] In some embodiments, two battery cells (120) may be placed between two closest adjacent heat-absorbing pads (181). In this case, since at least one side of any battery cell (120) is in contact with the heat-absorbing pad (181), even if a thermal event occurs in a battery cell (120), heat transfer to the neighboring battery cell (120) may be minimized.

[0110] The above heat absorption pad (181) has an outer shape corresponding to the complex shape of the cooling target (e.g., battery cell (120)), thereby having excellent heat absorption efficiency and contributing to improving energy density by increasing the space efficiency inside the battery pack (100).

[0111]

[0112] (Example 2)

[0113] FIG. 7 is a perspective view showing a heat absorbing pad (180) according to one embodiment of the present invention, and FIG. 8 is a cross-sectional view showing a cross-section of the heat absorbing pad (180) of FIG. 7 taken along line VIII-VIII'.

[0114] Referring to FIGS. 7 and 8, the heat-absorbing pad (180) may include bends, such as embossed structures (1801, 1802) formed by a forming process. The embossed structures (1801, 1802) maintain a bended state even when no external force is applied. In some embodiments, the embossed structures (1801, 1802) may be partially deformed in response to an external force applied thereto.

[0115] In some embodiments, the first embossing structure (1801) may include folds corresponding to the first layer (180a) and the second layer (180b). In some embodiments, the first layer (180a) and the second layer (180b) of the first embossing structure (1801) may have substantially similar fold directions and shapes. In some embodiments, the first layer (180a) and the second layer (180b) of the first embossing structure (1801) may extend at least partially while maintaining a constant gap.

[0116] In some embodiments, the second embossing structure (1802) may include folds corresponding to the shapes of the first layer (180a) and the second layer (180b). In some embodiments, the first layer (180a) and the second layer (180b) of the second embossing structure (1802) may have similar fold shapes but opposite fold directions. In some embodiments, the first layer (180a) and the second layer (180b) of the second embossing structure (1802) may extend at least partially while maintaining a constant gap.

[0117] The first embossing structure (1801) and / or the second embossing structure (1802) may be repeated multiple times at regular intervals. In some embodiments, the heat-absorbing pad (180) may have folded portions that are repeated at regular intervals in the first layer (180a). Although FIG. 8 illustrates a case where convex folded portions are repeated horizontally toward the top of the drawing, the present invention is not limited thereto. In some embodiments, the heat-absorbing pad (180) may have folded portions that are repeated at regular intervals in the second layer (180b). Although FIG. 8 illustrates a case where concave folded portions and convex folded portions are alternately repeated toward the bottom of the drawing, the present invention is not limited thereto.

[0118] The above heat absorption pad (180) can increase the adhesion to the object to be cooled through the first embossing structure (1801) and the second embossing structure (1802), thereby improving the heat absorption efficiency.

[0119]

[0120] (Example 3)

[0121] FIG. 9 is a perspective view showing a heat absorbing pad according to another embodiment of the present invention, and FIG. 10 is a cross-sectional view showing a cross-section of the heat absorbing pad (180) of FIG. 9 taken along line XX'.

[0122] Referring to FIGS. 9 and 10, the heat-absorbing pad (180) may have its entire first layer (180a) folded by a forming process. In addition, the second layer (180b) may be folded to correspond to the shape of the first layer (180a). The first layer (180a) and the second layer (180b) may extend while maintaining a constant distance from each other at least partially.

[0123] In some embodiments, the central portion of the first layer (180a) may be formed to be convex relative to the outer edge of the first layer (180a). In some embodiments, the central portion of the second layer (180b) may be neither concave nor convex relative to the outer edge of the second layer (180b), and may extend along the same plane as the outer edge.

[0124] The above-described heat-absorbing pad (180) can be formed into a shape that generally matches the external shape of the object to be cooled. The shape of the heat-absorbing pad (180) can maintain a generally bent state even when no external force is applied by the object to be cooled. In some embodiments, the heat-absorbing pad (180) can be partially deformed in compliance with the external force applied by the object to be cooled.

[0125] The above heat-absorbing pad (180) has an overall folded shape, thereby increasing the adhesion to the object to be cooled, thereby improving the heat-absorbing efficiency.

[0126]

[0127] (Example 4)

[0128] Fig. 11 is a side view schematically showing an electric vehicle (10) according to one embodiment of the present invention. Fig. 12 is a schematic diagram conceptually showing a battery pack (100) and other components mounted on the electric vehicle (10).

[0129] Referring to FIGS. 11 and 12, an electric vehicle (10) according to one embodiment of the present invention may include at least one battery pack (100). The electric vehicle (10) may include, for example, a body having a space for accommodating at least the battery pack (100). For example, the electric vehicle (10) may be a battery electric vehicle (BEV), a plug-in hybrid-electric vehicle (PHEV), or a full hybrid-electric vehicle (FHEV).

[0130] The electric vehicle (10) may include one or more electrical machines (214) mechanically coupled to one or more gearboxes or hybrid transmissions (216). The electrical machines (214) may operate as motors or generators. In addition, when the electric vehicle (10) is a PHEV or FHEV, the electric vehicle (10) may include an engine (218), and the hybrid transmission (216) may be mechanically coupled to the engine (218).

[0131] Additionally, the hybrid transmission (216) may be mechanically coupled to a drive shaft (220) that is mechanically coupled to a wheel (222). The electric machine (214) may be configured to propel or decelerate the vehicle depending on the on / off state of the engine (218), or may act as a generator to recover energy. The electric machine (214) may allow the engine (218) to operate at a more efficient speed to reduce exhaust emissions, and may allow the electric vehicle (10) to turn off the engine (218) and operate in an electric mode under certain conditions. When the electric vehicle (10) is a BEV, the engine (218) is omitted.

[0132] The battery pack (100) stores energy used by the electrical machine (214), and has been described with reference to FIGS. 1 to 9, so a duplicate description will be omitted. The battery pack (100) can provide a high-voltage direct current (DC) output. The contactor module (242) can include one or more contactors configured to isolate the battery pack (100) from the high-voltage bus (252) when opened, and connect the battery pack (100) to the high-voltage bus (252) when closed.

[0133] One or more inverters (226) may be electrically connected to the high voltage bus (252). The inverters (226) are also connected to the electrical machine (214) and may be capable of bidirectionally transferring energy between the battery pack (100) and the electrical machine (214). For example, the battery pack (100) may provide a DC voltage while the electrical machine (214) operates on three-phase AC. The inverter (226) may convert the DC voltage into three-phase AC current to operate the electrical machine (214). In regenerative mode, the inverter (226) may convert the three-phase AC current from the electrical machine (214) into a DC voltage that may be applied to the battery pack (100).

[0134] In some embodiments, the battery pack (100) may provide energy for other electrical systems of the vehicle in addition to energy for vehicle propulsion. The electric vehicle (10) may include a DC / DC converter module (228) that converts a high voltage DC output from a high voltage bus (252) to a low voltage DC level of a low voltage bus (254) that is compatible with a low voltage load (256). The output of the DC / DC converter module (228) may be electrically connected to an auxiliary battery (230) (e.g., a 12 V battery) to charge the auxiliary battery (230). The low voltage load (256) may be electrically connected to the auxiliary battery (230) via the low voltage bus (254). One or more high voltage loads (246) may be connected to the high voltage bus (252). The high voltage loads (246) may be, for example, a fan, an electric heating element, and / or an air conditioner compressor.

[0135] The electric vehicle (10) may be configured to recharge the battery pack (100) with an external power source (236). In some embodiments, the external power source (236) may be electrically connected to an electric vehicle supply equipment (EVSE) (238). The external power source (236) may supply DC or AC power to the EVSE (238), and the EVSE (238) may include circuitry that manages and controls the transfer of energy between the external power source (236) and the electric vehicle (10).

[0136] The EVSE (238) may include a charging connector (240) that may be connected to a charging port (234) of the electric vehicle (10). The charging port (234) may be any port that may transmit power from the EVSE (238) to the electric vehicle (10). The charging port (234) may be electrically connected to a power conversion module (232). The power conversion module (232) processes power from the EVSE (238) and converts it into a voltage and current level suitable for the battery pack (100).

[0137] In some embodiments, the battery pack (100) may be electrically connected to the auxiliary battery (230). The auxiliary battery (230) may be configured to supply power necessary to perform some functions of the battery pack (100).

[0138] All functions of the electric vehicle (10) described above can be controlled by the system controller (248).

[0139] While the embodiments of the present invention have been described in detail above, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, modifications to future embodiments of the present invention will not depart from the scope of the invention.

[0140] [Explanation of symbols]

[0141] 100: Battery pack

[0142] 101: Pack Housing

[0143] 110: Lower case

[0144] 110FP: Heat Sink

[0145] 110P: Plate part

[0146] 110S: Sidewall

[0147] 116: Cross beam

[0148] 120: Battery cells

[0149] 130: Center beam

[0150] 140: Exhaust system

[0151] 160: Pack gasket

[0152] 170: Upper case

[0153] 180, 181: Heat absorbing pad

[0154] 214: Electrical Machine

[0155] 216: Transmission

[0156] 218: Engine

[0157] 226: Inverter

[0158] 228: DC / DC converter module

[0159] 230: Auxiliary battery

[0160] 232: Power conversion module

[0161] 234: Charging port

[0162] 236: External power

[0163] 238: Electric vehicle charging station

[0164] 240: Charging connector

[0165] 242: Contactor module

[0166] 246: High voltage load

[0167] 248: System Controller

[0168] 252: High voltage bus

[0169] 256: Low voltage load

Claims

1. A heat absorbing pad comprising a pouch having an internal space and a heat absorbing material accommodated in the internal space, The above pouch includes a folded portion processed by a forming process to define the internal space, The above-mentioned bending part is a heat-absorbing pad for a secondary battery that maintains a bent state when no external force is applied from outside the pouch.

2. In paragraph 1, A heat-absorbing pad for a secondary battery, characterized in that the pouch includes folded portions having shapes corresponding to each other in each of the first layer and the second layer.

3. In paragraph 1, The above pouch comprises a first layer and a second layer facing each other while defining the internal space, A heat-absorbing pad for a secondary battery, characterized in that the first layer and the second layer extend at least partially while maintaining a constant gap from each other in the above-mentioned bending portion.

4. In paragraph 1, A heat absorbing pad for a secondary battery, further comprising a superabsorbent resin, characterized in that the heat absorbent material is absorbed into the superabsorbent resin.

5. In paragraph 4, A heat absorbing pad for a secondary battery, characterized in that the superabsorbent resin is in a powder state and the heat absorbing material is water.

6. In paragraph 1, The above pouch comprises a first layer and a second layer facing each other while defining the internal space, A heat-absorbing pad for a secondary battery, wherein the pouch includes a pattern of the folded portion repeated multiple times at predetermined intervals in at least one of the first layer and the second layer.

7. In a vertical coordinate system defined by the first, second, and third directions which are perpendicular to each other, A plurality of battery cells arranged in the first direction; At least one heat absorbing pad disposed between the plurality of battery cells; and A pack housing for accommodating the plurality of battery cells; Including, The above absorbent pad: A pouch including a folded portion corresponding to at least a portion of the outer shape of the battery cell; and Superabsorbent resin and an endothermic substance absorbed in the superabsorbent resin; A battery pack comprising:

8. In paragraph 7, A battery pack characterized in that the above heat-absorbing pad is provided between two adjacent battery cells.

9. In paragraph 7, A battery pack characterized in that the folded portion of the above pouch maintains a folded state when no external force is applied by the battery cells.

10. In paragraph 7, The above heat absorbing pad is provided between the battery cell and the pack housing, The above heat-absorbing pad includes a bend corresponding to the shape of the battery cell and the pack housing, A battery pack characterized in that the above-mentioned bending portion maintains a bent state when no external force is applied by the battery cell and the pack housing.

11. In paragraph 7, The above pouch comprises a first layer and a second layer facing each other while defining the internal space, A battery pack characterized in that the first layer and the second layer extend at least partially from each other while maintaining a constant gap at the above-mentioned bending portion.

12. In paragraph 11, A battery pack characterized in that the center of the first layer is formed to be convex compared to the outer edge of the first layer, and the entire center and outer edge of the first layer are folded.

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