Heat absorption pad for secondary battery and battery pack including same

Abstract

A heat-absorbing pad for a secondary battery is provided, which includes a pouch having an internal space and a heat-absorbing material accommodated in the internal space, wherein the pouch includes a folding portion processed by a forming process to define the internal space, and the folding portion maintains a folded state when no external force is applied from outside the pouch.

Description

[Technical Field]

[0001] The present invention relates to a heat absorption pad for a secondary battery and a battery pack including the same, and more specifically to a heat absorption pad for a secondary battery that has excellent heat absorption efficiency and can contribute to improving energy density, and a battery pack including the same.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0008631, filed January 19, 2024, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for a variety of cordless devices, such as handsets, laptops, and cordless vacuum cleaners. In recent years, improvements in energy density and economies of scale have dramatically reduced the manufacturing cost per unit capacity of secondary batteries. As the driving range of battery electric vehicles (BEVs) has increased to the same level as fuel-powered vehicles, the primary use of secondary batteries has shifted from mobile devices to mobility.

[0004] Meanwhile, in recent years, there has been an increasing demand for large-capacity battery packs that are used in electric vehicles, etc. Large-capacity battery packs installed in automobiles are required to have not only larger capacity but also improved safety. Summary of the Invention [Problem to be solved by the invention]

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

[0006] A second technical problem to be achieved by the present invention is to provide a battery pack that has excellent heat absorption efficiency and can contribute to improving energy density. [Means for solving the problem]

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

[0008] In some embodiments, the pouch can include folds in the first layer and the second layer that have corresponding configurations.

[0009] In some embodiments, the pouch includes a first layer and a second layer facing each other while defining the interior space, and at the folded portion, the first layer and the second layer can be extended while maintaining a constant distance from each other at least partially.

[0010] In some embodiments, the heat-absorbing pad for a secondary battery may further include a highly absorbent resin, and the heat-absorbing substance may be absorbed into the highly absorbent resin.

[0011] In some embodiments, the superabsorbent resin may be in a powder form and the endothermic material may be water.

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

[0013] To achieve the second technical problem, the present invention provides a battery pack including, in a vertical coordinate system defined by a first direction, a second direction, and a third direction that are perpendicular to each other, a plurality of battery cells arranged in the first direction, at least one heat absorption pad arranged between the plurality of battery cells, and a pack housing that accommodates the plurality of battery cells, wherein the heat absorption pad includes a pouch including a folded portion that corresponds to at least a portion of the outline of the battery cell, a superabsorbent resin, and a heat absorption material absorbed in the superabsorbent resin.

[0014] In some embodiments, the heat absorption 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 cell.

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

[0017] In some embodiments, the pouch includes a first layer and a second layer facing each other while defining the interior space, and at the folded portion, the first layer and the second layer can be extended while maintaining a constant distance from each other at least partially.

[0018] In some embodiments, the center of the first layer is formed convexly relative to the outer edge of the first layer, and the entire center and outer edge of the first layer may be folded. [Effects of the Invention]

[0019] The heat-absorbing pad of the present invention has an outer shape that corresponds to the complex shape of the object to be cooled, thereby having excellent heat absorption efficiency, and has the effect of contributing to an improvement in energy density by increasing the internal space efficiency.

[0020] The effects 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 from the following description by a person having ordinary skill in the art to which the exemplary embodiments of the present disclosure belong. In other words, unintended effects accompanying the implementation of the exemplary embodiments of the present disclosure can also be derived from the exemplary embodiments of the present disclosure by a person having ordinary skill in the art. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective view of a battery pack according to an exemplary embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view illustrating some elements of a battery pack according to an exemplary embodiment of the present invention. [Figure 3] 3 is a side cross-sectional view showing a cross section of the heat-absorbing pad taken along line III-III' in FIG. 1. FIG. [Figure 4] 1 is an enlarged perspective view showing a state in which a battery cell is mounted in a lower case according to an embodiment of the present invention; FIG. [Figure 5] 4 is a schematic side cross-sectional view showing the heat-absorbing pad inserted between battery cells. FIG. [Figure 6] 6 is a side cross-sectional view showing a state in which the heat-absorbing pad of FIG. 5 is not in contact with the battery cell. [Figure 7] 1 is a perspective view showing a heat-absorbing pad according to an embodiment of the present invention; [Figure 8] 8 is a cross-sectional view showing the cross section of the heat-absorbing pad of FIG. 7 taken along line VIII-VIII'. FIG. [Figure 9] FIG. 10 is a perspective view showing a heat-absorbing pad according to another embodiment of the present invention. [Figure 10]10 is a cross-sectional view showing the cross section of the heat-absorbing pad of FIG. 9 taken along line XX'. FIG. [Figure 11] 1 is a side view schematically illustrating an electrified vehicle according to an embodiment of the present invention. [Figure 12] FIG. 2 is a schematic diagram conceptually showing a battery pack and other components mounted on the electric vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the inventive concept will now be described in detail with reference to the accompanying drawings. However, the embodiments of the inventive concept can be modified into various different forms, and the scope of the inventive concept should not be construed as being limited by the embodiments described below. The embodiments of the inventive concept are preferably construed as being provided to more completely explain the inventive concept to those of ordinary skill in the art. The same reference numerals refer to the same elements throughout. Furthermore, various elements and regions in the drawings are drawn schematically. Therefore, the inventive concept is not limited by the relative sizes or spacings depicted in the accompanying drawings.

[0023] Terms such as "first," "second," etc. may be used to describe various components, but the components are not limited by these terms. These terms are used only to distinguish one component from another. For example, a first component may be designated a "second component," and vice versa, without departing from the scope of the inventive concept.

[0024] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the concept of the present invention. A singular expression includes a plural expression unless the context clearly indicates otherwise. In this application, expressions such as "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, and are understood not to preclude the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0025] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the concept of the present invention belongs. Furthermore, terms defined in commonly used dictionaries can be interpreted to have a meaning consistent with what they mean in the context of the relevant art, and unless explicitly defined herein, they should not be interpreted as overly formal.

[0026] In other embodiments, the order of certain steps may be different from that described, for example, two steps described in succession may be performed substantially simultaneously or may be performed in the reverse order from that described.

[0027] In the accompanying drawings, variations in the shapes shown may be expected due, for example, to manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as limited to the specific shapes of regions shown herein and may include, for example, variations in shapes resulting from the manufacturing process. As used herein, the term "and / or" includes each and every combination of one or more of the referenced elements. Furthermore, the term "substrate" as used herein may refer to the substrate itself or a laminated structure including the substrate and a predetermined layer or film formed on its surface. Furthermore, as used herein, the term "surface of the substrate" may refer to the exposed surface of the substrate itself or the outer surface of a predetermined layer or film formed on the substrate.

[0028] (First embodiment) FIG. 1 is a perspective view of a battery pack 100 according to an exemplary embodiment of the present invention.

[0029] FIG. 2 is a perspective view showing some elements of battery pack 100 according to an exemplary embodiment of the present invention.

[0030] In Figures 1 and 2, the battery pack 100 is shown as being defined in a vertical coordinate system in which a first direction is along the X axis, a second direction is along the Y axis, and a third direction is along the Z axis, all of which are perpendicular to one another. However, the first direction, second direction, and third direction may be perpendicular to one another, and are not particularly limited thereto.

[0031] 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 the final form of a battery system to be installed in a mobility device or the like. Hereinafter, a secondary battery may refer to any battery cell that can be charged and discharged.

[0032] A pack housing 101 that defines the appearance of the battery pack 110 may include the lower case 110 and the upper case 170 .

[0033] The lower case 110 can provide an accommodating space 119 for mounting a plurality of battery cells 120. In some embodiments, the lower case 110 can 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). The X-axis direction, the Y-axis direction, and the Z-axis direction can be substantially perpendicular to each other. Unless otherwise specified, the definitions of directions are the same for the following drawings.

[0034] A plurality of battery cells 120 may be disposed on the plate portion 110P of the lower case 110. The plate portion 110P may support the plurality of battery cells 120. The plate portion 110P may include substantially parallel upper and lower surfaces. 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 surface opposite to the upper surface of the plate portion 110P.

[0035] The sidewall 110S may horizontally surround the plurality of battery cells 120. The sidewall 110S may laterally protect the plurality of battery cells 120. The sidewall 110S may include a first sidewall 111, a second sidewall 112, a third sidewall 113, and a fourth sidewall 114. The first to fourth sidewalls 111, 112, 113, and 114 may be fixed to each other by a method such as friction stir welding or spot welding, and are not particularly limited thereto.

[0036] The first side wall 111 and the second side wall 112 may be substantially perpendicular to the second direction (e.g., the Y-axis direction). The third side wall 113 and the fourth side wall 114 may be substantially perpendicular to the first direction (e.g., the X-axis direction). In some embodiments, the first side wall 111 and the second side wall 112 may cover the side surfaces of the plate portion 110P. In some embodiments, the third side wall 113 and the fourth side wall 114 may be disposed on the plate portion 110P.

[0037] In some embodiments, the first to fourth side walls 111, 112, 113, and 114 may be provided by an extrusion process. According to an exemplary embodiment, the first to fourth side walls 111, 112, 113, and 114 may include an internal empty space, thereby reducing the weight of the side wall 110S. According to an exemplary embodiment, the empty space in the first to fourth side walls 111, 112, 113, and 114 may be any one of a gas venting path and a coolant channel.

[0038] 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. Based on what is described herein, a person skilled in the art can easily reach a battery pack employing a battery module including a module frame that exposes one side edge of the battery cell.

[0039] In some embodiments, the storage space 119 can be divided into two or more compartment spaces 119d by one or more compartment beams 130, 116. The compartment beams 130, 116 can include a center beam 130. In some embodiments, the compartment beams 130, 116 can include one or more cross beams 116.

[0040] The center beam 130 can isolate elements mounted on the lower case 110 from one another, thereby protecting the multiple battery cells 120 and preventing undesired short circuits between them.

[0041] The center beam 130 may extend between the third side wall 113 and the fourth side wall 114. The center beam 130 may extend in a first direction (e.g., 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 separate 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 storage space 119 into two regions in a second direction (e.g., the Y-axis direction).

[0042] In some embodiments, the cross beam 116 can be provided to divide the storage space 119 into two or more regions in a first direction (e.g., the X-axis direction). The cross beam 116 can further separate elements separated by the center beam 130.

[0043] Some of the cross beams 116 may extend in a second direction (e.g., the Y-axis direction) between the center beam 130 and the first side wall 111. Other cross beams 116 may extend in the second direction (e.g., 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 one battery cell stack or a group of battery cells is housed.

[0044] 1 is a non-limiting example and does not limit the technical concept of the present invention in any way. Those skilled in the art can easily arrive at battery packs including various arrangements and numbers of center beams and battery cells based on what is described herein.

[0045] 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 coupled to the plurality of exhaust devices 140. The plurality of exhaust holes may be configured to provide a path for exhausting gas and heat inside the battery pack 100.

[0046] The multiple exhaust devices 140 may be configured to slow thermal propagation by releasing hot gases inside the battery pack 100 to the outside when at least one of the multiple battery cells 120 is in a thermal runway state.

[0047] Here, thermal runaway of the battery cells 120 is a state in which the temperature change of the battery cells 120 accelerates the temperature change, which is an uncontrollable positive feedback. The battery cells 120 in the thermal runaway state exhibit a rapid temperature rise and can emit a large amount of high-pressure gas and combustion debris.

[0048] In some embodiments, the plurality of first recessed guides 151 can be disposed on the side wall 110S. The plurality of first recessed guides 151 can be disposed on corners 110C of the upper surface of the side wall 110S. The plurality of first recessed guides 151 can be coupled to the corners 110C of the upper surface of the side wall 110S. The plurality of first recessed guides 151 can be partially recessed in the side wall 110S. The plurality of first recessed guides 151 can be partially protruding from the side wall 110S.

[0049] In some embodiments, the plurality of second recessed guides 153 may be disposed on the side wall 110S. The plurality of second recessed guides 153 may be disposed on the upper surface of the side wall 110S. The plurality of second recessed guides 153 may be interposed between the corners 110C of the side wall 110S. The plurality of second recessed guides 153 may be interposed between the plurality of first recessed guides 151. The plurality of second recessed guides 153 may be coupled to the upper surface of the side wall 110S. The plurality of second recessed guides 153 may be partially recessed in the side wall 110S. The plurality of second recessed guides 153 may partially protrude from the side wall 110S.

[0050] In some embodiments, each of the plurality of first embedded guides 151 and the plurality of second embedded guides 153 may include a metallic material. For example, each of the plurality of first embedded guides 151 and the plurality of second embedded guides 153 may include aluminum. For example, each of the plurality of first embedded guides 151 and the plurality of second embedded guides 153 may include steel, such as carbon steel, nickel steel, chromium steel, nickel-chromium steel, and manganese steel.

[0051] Battery pack 100 may further include electrical components. In some embodiments, the electrical components may be mounted on lower case 110. In some embodiments, the electrical components may be disposed between fourth side wall 114, on which exhaust device 140 is installed, and multiple battery cells 120. In some embodiments, the electrical components may include any electronic elements necessary to operate the battery pack.

[0052] 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 the plurality of battery cells 120 and measuring the temperature at a predetermined location inside the battery pack 100. In some embodiments, the battery pack 100 may include instruments for measuring the voltage, current, and temperature described above.

[0053] Balancing the battery pack 100 is an operation to reduce the deviation between the battery cells 120. Controlling the battery pack 100 includes preventing overcharging, overdischarging, and overcurrent. Through monitoring, balancing, and control, the battery pack 100 can operate under optimal conditions, thereby preventing or reducing a shortening of the lifespan of each of the battery cells 120.

[0054] The electrical components may further include a cooling device, a power relay assembly (PRA), a safety plug, etc. The cooling device may include a cooling fan. The cooling fan circulates air inside the battery pack 100 to prevent overheating of each of the battery cells 120. The PRA may be configured to supply or cut off power from the high-voltage battery to an external load (e.g., a vehicle motor). The PRA may protect the battery cells 120 and the external load (e.g., a vehicle motor) by cutting off power supply to the external load (e.g., a vehicle motor) in the event of an abnormal voltage such as a voltage surge.

[0055] The battery pack 100 may further include a plurality of bus bars configured to electrically connect the plurality of battery cells 120. The plurality of battery cells 120 may be connected in series and / or parallel by the plurality of bus bars. This allows the battery pack 100 to be configured to output a high voltage to an external load (e.g., a vehicle motor).

[0056] 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 together, 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 apply pressure to the gasket 160 such that some deformation occurs in the gasket 160. As a result, the battery pack 100 may be sealed and external fluid may be blocked from the internal space of the battery pack 100.

[0057] The upper case 170 may be coupled to the lower case 110 to cover the storage 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 the plurality of battery cells 120 and electrical components. The edge portion is a surface that contacts the lower case 110. In some embodiments, the upper case 170 may have a flat plate shape, in which case the edge portion may horizontally surround the main surface. In some embodiments, the main surface may be elevated compared to the edge portion, and the edge portion and the main surface may be connected by a curved portion.

[0058] In some embodiments, the upper case 170 may be coupled to the side wall 110S of the lower case 110 by a plurality of first embedded guides 151 and second embedded guides 153. According to an exemplary embodiment, the battery pack 100 may further include elements coupled to the plurality of first embedded guides 151 and second embedded guides 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.

[0059] The battery pack 100 may further include a heat absorbing pad 180. Figure 3 is a side cross-sectional view showing a cross section of the heat absorbing pad 180 taken along line III-III' in Figure 1 .

[0060] 1 and 3, the heat absorption pad 180 may be configured to absorb heat generated in the battery cell 120 and / or block or delay the transfer of the heat.

[0061] In some embodiments, the heat absorption pad 180 may be provided on top of the battery cell 120. In some embodiments, the heat absorption pad 180 may be provided between the upper case 170 and the battery cell 120.

[0062] The 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 form the exterior 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 to each other, and the internal space may be defined between the first layer 180a and the second layer 180b.

[0063] The laminate sheet 180c may be a single layer or a laminate of two or more layers. In some embodiments, the laminate sheet 180c may have a multi-layer structure including an outermost resin layer made of an insulating material such as polyethylene terephthalate (PET) or nylon, an aluminum metal layer that maintains mechanical strength and prevents moisture and oxygen from penetrating, and an inner resin layer made of a polyolefin-based material that has thermal adhesive properties and serves as a sealant.

[0064] The heat-absorbing material may be absorbed in the absorbent member 180p and may be a material that can change phase in response to a temperature change. The laminate sheet 180c may be configured to be deformable in response to the phase change of the heat-absorbing material.

[0065] In some embodiments, the absorbent member 180p may include an absorbent resin such as a super absorbent polymer (SAP). The super absorbent resin may be any material known in the art, and is not particularly limited thereto. In some embodiments, the super absorbent resin 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, but is not limited to, powder, granules, pellets, platelets, slabs, etc.

[0066] The absorbent member 180p may have a liquid endothermic substance absorbed therein. In some embodiments, the endothermic substance may include a material that can be repeatedly vaporized and condensed within the operating temperature range of the battery cell 120 and within a pressure range both inside and outside atmospheric pressure. For example, the endothermic substance may include a material that can be vaporized or condensed within a pressure range of about 1 atmosphere to about 10 atmospheres and at a temperature of about 70°C to about 130°C.

[0067] In some embodiments, the heat-absorbing material may include water, ethanol, isopropyl alcohol, etc. The heat-absorbing material may be absorbed in the absorbent member 180p in a liquid state. The heat-absorbing material may be vaporized by heat transferred from the battery cell 120 through the second layer 180b of the laminate sheet 180c. The vaporized heat-absorbing material exists in a gaseous state in the laminate sheet 180c, but may condense and liquefy as it cools, and may be reabsorbed in the absorbent member 180p. The heat transferred from the battery cell 120 is used to increase the temperature of the heat-absorbing material and provide enthalpy of vaporization, thereby reducing or preventing the heat from being transferred to other adjacent battery cells 120.

[0068] The heat-absorbing pad 180 may include a bent portion 180f. The bent portion 180f may be formed by a forming process. The forming process may be a process of pressing the laminate sheet 180c so that the laminate sheet 180c has a desired shape. The laminate sheet 180c may be formed into an at least partially bent shape through the forming process.

[0069] 3, the bent portion 180f can maintain the bent state even when no external force is applied. That is, the bent state can be maintained even when no external force is applied to the heat absorption pad 180 by the upper case 170 and the battery cell 120. However, the bent state of the heat absorption pad 180 when no external force is applied does not necessarily have to be exactly the same as the bent state of the heat absorption pad 180 when assembled between the upper case 170 and the battery cell 120. In some embodiments, the bent state of the heat absorption pad 180 when no external force is applied may be slightly deformed when assembled between the upper case 170 and the battery cell 120, but the overall bent state of the heat absorption pad 180 may be generally maintained.

[0070] In some embodiments, the bend 180f may be provided only in the first layer 180a. In some embodiments, the bend 180f may be provided only in the second layer 180b. In some embodiments, the bend 180f may be provided in both the first layer 180a and the second layer 180b.

[0071] In some embodiments, the bent portion 180f may be provided in the first layer 180a and the second layer 180b, and the bent portion of the first layer 180a and the bent portion of the second layer 180b may have corresponding shapes. Here, "corresponding shapes" means that the bent shape and / or direction are the same or similar, although the degree of bending may vary slightly.

[0072] In some embodiments, the bent portions of the first layer 180a and the second layer 180b may be at least partially extended while maintaining a constant distance from each other. As shown in Fig. 3, each of the first layer 180a and the second layer 180b includes a portion that extends generally in the Z-axis direction and a flat portion that is bent from the portion and extends in a direction perpendicular to the Z-axis direction.

[0073] 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 shown in Figures 1 and 3, the laminate sheet 180c includes a pattern of folds 180f that is repeated three times in the X-axis direction and two times in the Y-axis direction.

[0074] In some embodiments, the heat absorption pad 180 may have a joining section 180m. In some embodiments, the joining section 180m may be formed by fusing opposing laminate sheets (i.e., the first layer 180a and the second layer 180b) of the heat absorption pad 180. In some embodiments, the heat absorption pad 180 may be configured such that the joining section 180m is opened or a specific portion of the joining section 180m is opened when a thermal event occurs therein.

[0075] As shown in FIG. 1, when a heat absorption pad 180 is placed between the upper surface of the battery cell 120 and the upper case 170, even if a thermal event occurs in a particular battery cell 120, the flame energy can be effectively weakened, and damage to the upper case 170 due to heat can be mitigated or prevented.

[0076] FIG. 4 is an enlarged perspective view showing a state in which the battery cell 120 is mounted in the lower case 110 according to an embodiment of the present invention.

[0077] 4, battery cell stacks S1, S2, ..., S6 are arranged in each area defined by the side walls 111, 112, 113, 114, the center beam 130, and the cross beam 116 of the lower case 110. Each of the battery cell stacks S1, S2, ..., S6 includes a plurality of battery cells 120. Hereinafter, the term "battery cell stack" may simply mean a collection of a plurality of battery cells, or may mean an assembly in which a plurality of battery cells are housed in a specific frame.

[0078] In some embodiments, the battery cell 120 may be a pouch-type battery cell, but the present invention is not limited thereto. In some embodiments, the battery cell 120 may be a cylindrical battery cell or a prismatic battery cell.

[0079] In some embodiments, the battery cell 120 may have a thin plate-shaped body and may have 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 stacked within a pouch made of a laminate sheet. An electrode tab may extend from at least one side of the electrode assembly and be connected to a cell lead. The positive and negative electrodes may be fabricated by coating at least one surface of a current collector with a slurry containing an electrode active material, a binder resin, a conductive material, and other additives. The positive electrode may be a conventional positive electrode active material, such as a lithium-containing transition metal oxide, and the negative electrode may be a conventional negative electrode active material, such as lithium metal, a carbon material, a metal compound, or a mixture thereof, capable of absorbing and releasing lithium ions. The separator may be a conventional porous polymer film used in lithium secondary batteries.

[0080] The electrolyte contained in the pouch together with the electrode assembly may be a typical electrolyte for lithium secondary batteries. The pouch is made of a sheet material and includes a receiving portion for containing the electrode assembly. The sheet material forming the pouch may have a multilayer structure including an outermost resin layer made of an insulating material such as polyethylene terephthalate (PET) or nylon, a metal layer made of aluminum material that maintains mechanical strength and prevents moisture and oxygen from penetrating, and an inner resin layer made of a polyolefin-based material that has thermal adhesiveness and serves as a sealant.

[0081] The sheet material forming the 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 for smooth adhesion between different materials and may be formed as a single layer or multiple layers. The material may typically be a polyolefin resin, or a polyurethane resin for smooth processing, or a mixture thereof.

[0082] The plurality of battery cells 120 may be arranged in a first direction (e.g., an 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., an 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., an X-axis direction).

[0083] 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., a 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., a 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., a Y-axis direction).

[0084] 5 is a schematic side cross-sectional view showing the heat absorption pad 181 inserted between the battery cells 120. The side cross-section shown in FIG. 5 is, for example, a cross-section taken along line V-V' in FIG.

[0085] 4 and 5, the heat absorption pad 181 may have a shape that extends in a second direction (e.g., Y-axis direction) that is generally the longitudinal direction of the battery cell 120. In some embodiments, the heat absorption pad 181 may extend in the second direction (e.g., Y-axis direction) and directly contact a side surface of an adjacent battery cell 120.

[0086] The heat absorption pad 181 may have a predetermined area along a plane perpendicular to a first direction (e.g., the X-axis direction). In some embodiments, the heat absorption pad 181 may be interposed between a pair of battery cells 120. A first side surface 181a forming one side of the heat absorption pad 181 may be in direct contact with one of the pair of battery cells 120. A second side surface 181b forming the other side of the heat absorption pad 181 may be in direct contact with the remaining battery cell 120 of the pair of battery cells 120.

[0087] In some embodiments, the side surfaces of the battery cells 120 may include curved portions. As shown in FIG. 5, the side surfaces 181a and 181b of the heat absorption pad 181 facing the battery cells 120 may have bent portions 181f corresponding to the curved portions of the side surfaces of the battery cells 120.

[0088] FIG. 6 is a side cross-sectional view showing a state in which the heat absorbing pad 181 of FIG. 5 is not in contact with the battery cell 120. As shown in FIG.

[0089] 6, the heat absorption pad 181 can generally maintain the bent state of the bent portion 181f even when not in contact with the battery cell 120. When the heat absorption pad 181 is in close contact with the adjacent battery cell 120 and when it is separated from the battery cell 120, the shape of the bent portion 181f may be slightly deformed, but the bent state of the bent portion 181f can generally be maintained.

[0090] 5, in some embodiments, the heat absorption pad 181 may be thermally coupled to the lower case 110 and may transfer heat transferred from the battery cells 120 to the plate portion 110P. In some embodiments, the heat absorption pad 181 may be thermally coupled to the upper case 170 and / or the heat absorption pad 180 (see FIG. 1). Here, the heat absorption pad 181 being "thermally coupled" to a certain object may mean that most of the heat emitted from the heat absorption pad 181 is removed through the object, for example, more than 50% of the heat emitted from the heat absorption pad 181 is removed through the object.

[0091] 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 channel configured to allow a cooling fluid to flow therethrough. Therefore, the 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. For this reason, the heat absorption pad 181 may be disposed closer to the lower case 110 than the upper case 170.

[0092] In some embodiments, the heat absorption pads 181 may be arranged alternately with the battery cells 120. In some embodiments, the heat absorption pads 181 may be provided one for every two or more battery cells 120. That is, two or more battery cells 120 may be arranged between the two nearest adjacent heat absorption pads 181.

[0093] In some embodiments, the heat absorption pads 181 may be provided at both ends in a first direction (e.g., the X-axis direction) of the plurality of battery cells 120 provided in one compartment space 119d. In this case, it is possible to effectively prevent or delay a thermal event occurring in one compartment space 119d from transferring to another adjacent compartment space 119d. In this case, the heat absorption pads 181 may be disposed so as to directly face the cross beam 116.

[0094] In some embodiments, two battery cells 120 may be disposed between the two closest adjacent heat absorption pads 181. In this case, at least one side of any battery cell 120 is in contact with the heat absorption pad 181, so that even if a thermal event occurs in a battery cell 120, heat transfer to the adjacent battery cell 120 may be minimized.

[0095] The heat absorption pad 181 has an outer shape that corresponds to the complex shape of the object to be cooled (e.g., the battery cell 120), and thus has excellent heat absorption efficiency, and has the effect of contributing to improving the energy density by increasing the space efficiency inside the battery pack 100.

[0096] (Second embodiment) 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'.

[0097] 7 and 8, the heat-absorbing pad 180 may include folded portions such as embossing structures 1801 and 1802 formed by a forming process. The embossing structures 1801 and 1802 maintain their folded state even when no external force is applied. In some embodiments, when an external force is applied, the embossing structures 1801 and 1802 may be partially deformed to accommodate the external force.

[0098] In some embodiments, the first embossing structure 1801 may include folded portions of corresponding shapes in 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 generally similar folded directions and shapes. In some embodiments, the first layer 180a and the second layer 180b of the first embossing structure 1801 may be extended while maintaining at least a constant distance between them.

[0099] In some embodiments, the second embossing structure 1802 may include folded portions of corresponding shapes in 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 folded shapes but folded in opposite directions. In some embodiments, the first layer 180a and the second layer 180b of the second embossing structure 1802 may be extended while maintaining at least a constant distance between them.

[0100] 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 repeated at regular intervals in the first layer 180a. Although FIG. 8 illustrates a state in which 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 repeated at regular intervals in the second layer 180b. Although FIG. 8 illustrates a state in which concave folded portions and convex folded portions are alternately repeated toward the bottom of the drawing, the present invention is not limited thereto.

[0101] The heat absorbing pad 180 can increase the adhesion to the object to be cooled by the first embossing structure 1801 and the second embossing structure 1802, thereby improving the heat absorbing efficiency.

[0102] (Third embodiment) 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'.

[0103] 9 and 10, the heat-absorbing pad 180 may have the entire first layer 180a folded by a forming process. Also, 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 be at least partially extended while maintaining a predetermined distance from each other.

[0104] In some embodiments, the center of the first layer 180a may be formed convexly relative to the outer edge of the first layer 180a, and in some embodiments, the center of the second layer 180b may be extended along the same plane as the outer edge of the second layer 180b, rather than being concave or convex relative to the outer edge of the second layer 180b.

[0105] The heat-absorbing pad 180 may be shaped to generally match the contour of the object to be cooled. This shape of the heat-absorbing pad 180 may maintain an alternative folded state even when no external force is applied by the object to be cooled. In some embodiments, when an external force is applied by the object to be cooled, the heat-absorbing pad 180 may be partially deformed to accommodate the external force.

[0106] The heat absorbing pad 180 has a folded shape as a whole, thereby increasing the adhesion to the object to be cooled, thereby improving the heat absorbing efficiency.

[0107] (Fourth embodiment) Fig. 11 is a side view schematically showing an electrified 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.

[0108] 11 and 12, an electric vehicle 10 according to an embodiment of the present invention can include at least one battery pack 100. The electric vehicle 10 can include, for example, a vehicle body having an accommodation space for accommodating at least the battery pack 100. For example, the electric vehicle 10 can be a battery electric vehicle (BEV), a plug-in hybrid-electric vehicle (PHEV), or a full hybrid-electric vehicle (FHEV).

[0109] The electric vehicle 10 may include one or more electric machines 214 mechanically coupled to one or more gearboxes or hybrid transmissions 216. The electric machines 214 may operate as motors or generators. If 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.

[0110] The hybrid transmission 216 may also be mechanically coupled to a drive shaft 220 that is mechanically coupled to wheels 222. The electric machine 214 may propel or slow down depending on whether the engine 218 is on or off, and 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 emissions, and under certain conditions may allow the electric vehicle 10 to operate in electric mode with the engine 218 off. When the electric vehicle 10 is a BEV, the engine 218 is omitted.

[0111] The battery pack 100 stores energy used by the electric machine 214 and has been described with reference to FIGS. 1 to 9, so a redundant 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 a high-voltage bus 252 when opened and to couple the battery pack 100 to the high-voltage bus 252 when closed.

[0112] One or more inverters 226 may be electrically coupled to the high-voltage bus 252. The inverters 226 may also be coupled to the electric machine 214 and may transfer energy bidirectionally between the battery pack 100 and the electric machine 214. For example, the battery pack 100 may provide a DC voltage while the electric machine 214 operates on three-phase AC. The inverters 226 may convert the DC voltage to three-phase AC current for the electric machine 214 to operate. In a regeneration mode, the inverters 226 may convert the three-phase AC current from the electric machine 214 to a DC voltage that can be applied to the battery pack 100.

[0113] In some embodiments, the battery pack 100 can provide energy for other vehicle electrical systems in addition to energy for propulsion of the vehicle. The electric vehicle 10 can 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 on a low-voltage bus 254 that is compatible with low-voltage loads 256. The output of the DC / DC converter module 228 can be electrically coupled to an auxiliary battery 230 (e.g., a 12V battery) to charge the auxiliary battery 230. The low-voltage loads 256 can be electrically coupled to the auxiliary battery 230 via the low-voltage bus 254. One or more high-voltage loads 246 can be coupled to the high-voltage bus 252. The high-voltage loads 246 can be, for example, a fan, an electric heating element, and / or an air conditioner compressor.

[0114] 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 coupled to an electric vehicle supply equipment (EVSE) 238. The external power source 236 may provide DC or AC power to the EVSE 238, and the EVSE 238 may include circuitry to manage and control energy transfer between the external power source 236 and the electric vehicle 10.

[0115] The EVSE 238 may include a charging connector 240 that may be coupled to a charging port 234 of the electric vehicle 10. The charging port 234 may be any port that can transmit power from the EVSE 238 to the electric vehicle 10. The charging port 234 may be electrically coupled to a power conversion module 232. The power conversion module 232 processes and converts the power from the EVSE 238 to voltage and current levels suitable for the battery pack 100.

[0116] In some embodiments, the battery pack 100 can be electrically coupled to the auxiliary battery 230. The auxiliary battery 230 can be configured to provide the power necessary to perform some functions of the battery pack 100.

[0117] All of the functions of the electric vehicle 10 described above can be controlled by the system controller 248.

[0118] Although the embodiments of the present invention have been described in detail above, those skilled in the art can make various modifications to the present invention without departing from the spirit and scope of the present invention as defined in the appended claims. Therefore, future changes to the embodiments of the present invention cannot depart from the technology of the present invention. [Explanation of symbols]

[0119] 100: Battery pack 101: Pack Housing 110: Lower case 110FP: Heat sink 110P: Plate part 110S: Side wall 116: Cross beam 120: Battery cell 130: Center beam 140: Exhaust system 160: Pack gasket 170: Upper case 180, 181: Heat absorption pad 214: Electrical Machine 216: Transmission 218: Engine 226: Inverter 228: DC / DC converter module 230: Auxiliary battery 232: Power conversion module 234: Charging port 236: External power supply 238: Electric vehicle charging equipment 240: Charging connector 242: Contactor module 246: High voltage load 248: System Controller 252: High voltage bus 256: Low voltage load

Claims

1. A heat-absorbing pad comprising a pouch having an interior space and a heat-absorbing material contained within the interior space, the pouch includes a fold shaped to define the interior space; the folding portion maintains the folded state when no external force is applied from outside the pouch, The pouch includes a first layer and a second layer facing each other while defining the internal space, and the first layer and the second layer each include a folded portion having a shape corresponding to each other.

2. A heat absorption pad for a secondary battery as described in Claim 1, wherein, in the folded portion, the first layer and the second layer are extended while at least partially maintaining a constant distance from each other.

3. The heat-absorbing pad for a secondary battery according to claim 1 , further comprising a highly absorbent resin, wherein the heat-absorbing material is absorbed in the highly absorbent resin.

4. 4. The heat-absorbing pad for a secondary battery according to claim 3, wherein the highly absorbent resin is in a powder state and the heat-absorbing material is water.

5. the pouch includes a first layer and a second layer opposing each other and defining the interior space; The heat-absorbing pad for a secondary battery according to claim 1 , wherein the pouch includes a pattern of the folded portions that is repeated a plurality of times at predetermined intervals in at least one of the first layer and the second layer.

6. In a vertical coordinate system defined by a first direction, a second direction, and a third direction that are perpendicular to each other, a plurality of battery cells arranged in the first direction; at least one heat absorption pad disposed between the plurality of battery cells; a pack housing that houses the plurality of battery cells; Including, The heat-absorbing pad is a pouch including a fold portion corresponding to at least a portion of the outer shape of the battery cell; a high-absorbency resin and an endothermic substance absorbed in the high-absorbency resin; Including, The pouch includes a first layer and a second layer facing each other while defining an internal space, and the first layer and the second layer each include a folding portion having a shape corresponding to each other.

7. The battery pack of claim 6 , wherein the heat-absorbing pad is provided between two adjacent battery cells.

8. The battery pack according to claim 6 , wherein the folded portion of the pouch maintains the folded state when no external force is applied by the battery cell.

9. The heat absorption pad is provided between the battery cell and the pack housing; the heat absorption pad includes a bent portion corresponding to the shape of the battery cell and the pack housing; The battery pack according to claim 6 , wherein the bent portion maintains the bent state when no external force is applied by the battery cell and the pack housing.

10. A battery pack as described in claim 6, wherein, in the folded portion, the first layer and the second layer are extended while at least partially maintaining a constant distance from each other.

11. 11. The battery pack of claim 10, wherein a central portion of the first layer is convexly shaped compared to an outer edge of the first layer, and the central portion and the entire outer edge of the first layer are folded.

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