Battery pack

Abstract

A battery pack is provided, comprising a pack case including a lower case and an upper case defining an internal space, a plurality of battery cells provided within the internal space, a separation sheet provided between the bottom surface of the pack case and the plurality of battery cells, and a thermally conductive resin layer provided between the separation sheet and the plurality of battery cells, wherein the separation sheet and the thermally conductive resin layer are bonded together with a first adhesive force, which is the adhesive strength per unit area, and the first adhesive force is less than a second adhesive force, which is the adhesive strength per unit area when the pack case and the thermally conductive resin are bonded together.

Description

Technical Field

[0001] The present invention relates to a battery pack, and more specifically, to a battery pack in which a desired battery cell can be easily removed from a pack case, significantly improving the convenience of maintenance.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0048545 filed on April 13, 2023, and all the contents disclosed in the literature of the Korean patent application are included as part of this specification.

Background Art

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as an energy source for various wireless devices such as handsets, notebook computers, and wireless vacuum cleaners. In recent years, due to improvements in energy density and economies of scale, the manufacturing cost per unit capacity of secondary batteries has decreased epochally, and as the cruising range of battery electric vehicles (BEVs) has increased to a level equivalent to that of fuel vehicles, the main applications of secondary batteries have shifted from mobile devices to mobility.

[0004] On the other hand, in recent years, the demand for large-capacity battery packs applied to electric vehicles and the like has been increasing. A large-capacity battery pack mounted on a vehicle may cause thermal events due to temperature rise in some battery cells during the charging and discharging of a large number of battery cells, and sometimes, aftermeasures such as replacement of the problematic battery cells are required. Therefore, a solution that can make such aftermeasures easier is required.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The technical problem that this invention aims to solve is to provide a battery pack in which the convenience of maintenance is greatly improved by allowing the desired battery cell to be easily removed from the pack case. [Means for solving the problem]

[0006] To solve the above technical problems, the present invention provides a battery pack comprising a pack case including a lower case and an upper case defining an internal space, a plurality of battery cells provided within the internal space, a separation sheet provided between the bottom surface of the pack case and the plurality of battery cells, and a thermally conductive resin layer provided between the separation sheet and the plurality of battery cells, wherein the separation sheet and the thermally conductive resin layer are bonded together with a first adhesive force, which is the adhesive strength per unit area, and the first adhesive force is smaller than the second adhesive force, which is the adhesive strength per unit area when the pack case and the thermally conductive resin layer are bonded together.

[0007] In some embodiments, the first adhesive strength may be 10% to 70% of the second adhesive strength.

[0008] In some embodiments, the thermally conductive resin layer may be provided only between the separation sheet and the plurality of battery cells. In some embodiments, the thermally conductive resin layer may not be in contact with the pack case.

[0009] In some embodiments, the separation sheet may be a sheet that has adhesive properties to the pack case.

[0010] In some embodiments, the plurality of battery cells include one or more battery cell stacks, the surface of the battery cell stack facing the bottom surface facing the separator sheet, and the width of the separator sheet may be less than the width of the surface of the battery cell stack. In some embodiments, the separator sheet may extend along the side surface of the battery cell stack.

[0011] In some embodiments, the separation sheet includes a perforated line that crosses the separation sheet and may pass between the battery cell stack and the bottom surface.

[0012] In some embodiments, the thermally conductive resin layer may be placed only between the surface of the battery cell stack facing the bottom surface and the separation sheet. In some embodiments, one surface of the thermally conductive resin layer may be in contact with the separation sheet, and the other surface of the thermally conductive resin layer may be in contact with the surface of the battery cell stack.

[0013] In some embodiments, the plurality of battery cells include one or more battery cell stacks, and the separation sheet includes a first separation sheet and a second separation sheet, the first separation sheet being located between the battery cell stack and the bottom surface at one end of the battery cell stack, and the second separation sheet, separated from the first separation sheet, being located between the battery cell stack and the bottom surface at the other end of the battery cell stack.

[0014] In some embodiments, the battery cell stack can face the bottom surface directly between the first separation sheet and the second separation sheet.

[0015] Another aspect of the present invention provides a battery pack comprising a plurality of battery cells stacked in the first direction in a vertical coordinate system defined as a first, second, and third direction perpendicular to each other, a pack case including a lower case and an upper case, which includes an internal space capable of housing the plurality of battery cells, a separation sheet provided between the bottom surface of the pack case and the plurality of battery cells, and a thermally conductive resin layer provided between the separation sheet and the plurality of battery cells, wherein the separation sheet is configured to be separated from the thermally conductive resin layer by a shear force applied to the thermally conductive resin layer.

[0016] In some embodiments, the thermally conductive resin layer may not come into contact with the pack case.

[0017] In some embodiments, the lower case includes side walls and a cross beam extending across the lower case, and the separation sheet may be configured to be detachably attached to the side walls and / or the cross beam. [Effects of the Invention]

[0018] The battery pack of the present invention allows for easy removal of desired battery cells from the pack case, thus significantly improving the convenience of maintenance.

[0019] The effects that can be obtained from exemplary embodiments of the present invention are not limited to those mentioned above, and other effects not mentioned can be clearly derived and understood by a person of ordinary skill in the art to which the exemplary embodiments of this disclosure belong, from the following description. That is, unintended effects associated with carrying out exemplary embodiments of this disclosure can also be derived by a person of ordinary skill in the art from exemplary embodiments of this disclosure. [Brief explanation of the drawing]

[0020] [Figure 1] This is a perspective view of a battery pack according to an exemplary embodiment of the present invention. [Figure 2] This is a perspective view showing some elements of a battery pack according to an exemplary embodiment of the present invention. [Figure 3] This is a magnified perspective view showing how a battery cell is installed inside the lower case of one embodiment of the present invention. [Figure 4] This is an exploded perspective view showing how the separation sheet described above surrounds the bottom and a pair of sides of the first battery cell stack. [Figure 5] This is a perspective view showing how the separation sheet described above surrounds the bottom and a pair of sides of the first battery cell stack. [Figure 6]It is a side view showing a state where the separation sheet surrounds the bottom surface and a pair of side surfaces of the first battery cell stack. [Figure 7] It is a conceptual diagram showing a method of removing a specific battery cell stack in a battery pack according to an embodiment of the present invention. [Figure 8] It is a conceptual diagram showing a method of removing a specific battery cell stack in a battery pack according to an embodiment of the present invention. [Figure 9] It is a conceptual diagram showing a method of removing a specific battery cell stack in a battery pack according to an embodiment of the present invention. [Figure 10] It is a conceptual diagram showing a method of removing a specific battery cell stack in a battery pack according to an embodiment of the present invention. [Figure 11] It is a conceptual diagram showing a method of removing a specific battery cell stack in a battery pack according to an embodiment of the present invention. [Figure 12] It is an exploded perspective view showing a state where a pair of separation sheets according to another embodiment of the present invention surrounds a part of the bottom surface and a pair of side surfaces of the first battery cell stack. [Figure 13] It is a side view showing a state where the pair of separation sheets surrounds the bottom surface and a pair of side surfaces of the first battery cell stack. [Figure 14] It is a conceptual diagram showing a method of removing a specific battery cell stack in a battery pack according to another embodiment of the present invention. [Figure 15] It is a conceptual diagram showing a method of removing a specific battery cell stack in a battery pack according to another embodiment of the present invention. [Figure 16] It is a conceptual diagram showing a method of removing a specific battery cell stack in a battery pack according to another embodiment of the present invention. [Figure 17] It is an exploded perspective view showing a state where a separation sheet according to another embodiment of the present invention surrounds the bottom surface and a pair of side surfaces of the first battery cell stack. [Figure 18]This is a conceptual diagram illustrating a method for removing a specific battery cell stack in a battery pack according to another embodiment of the present invention. [Figure 19] This is a conceptual diagram illustrating a method for removing a specific battery cell stack in a battery pack according to another embodiment of the present invention. [Modes for carrying out the invention]

[0021] Preferred embodiments of the concept of the present invention will be described in detail below with reference to the attached drawings. However, embodiments of the concept of the present invention may be modified into various different forms, and the scope of the concept of the present invention should not be construed as being limited by the embodiments described above. It is preferable that embodiments of the concept of the present invention be construed as being provided to more fully explain the concept of the present invention to a person of average knowledge in the art. The same reference numerals mean the same element throughout. Furthermore, the various elements and areas in the drawings are depicted schematically. Therefore, the concept of the present invention is not limited by the relative sizes or spacings depicted in the attached drawings.

[0022] Terms such as "first," "second," etc., may be used to describe a variety of components, but the components are not limited by these terms. The terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the concept of the present invention, the first component may be named the second component, and conversely, the second component may be named the first component.

[0023] The terms used in this application are used solely to describe specific embodiments and are not intended to limit the concepts of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, expressions such as “includes” or “has” are intended to specify the existence of features, quantities, steps, operations, components, parts, or combinations thereof described in the specification, and are understood not to pre-exist to exclude the existence or possibility of adding one or more other features, quantities, steps, operations, components, parts, or combinations thereof.

[0024] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as those commonly understood by those of ordinary skill in the art to which the concepts of this invention pertain. Furthermore, terms defined in commonly used dictionaries may be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an overly formal sense unless explicitly defined herein.

[0025] Where a particular embodiment can be otherwise realized, a specific sequence of steps may be performed in a different order than that described. For example, two steps described consecutively may be performed substantially simultaneously, or in the reverse order of the description.

[0026] In the accompanying drawings, deformation of the shown shapes may be expected, for example, due to manufacturing techniques and / or tolerances. Therefore, embodiments of the present invention should not be construed as being limited to specific shapes of the regions shown herein, and may include, for example, changes in shape resulting from the manufacturing process. All terms used herein, "and / or," include each of the components mentioned and all combinations of one or more of them. The term "substrate" as used herein may mean the substrate itself or a laminated structure including a substrate and a predetermined layer or film formed on its surface. The term "surface of the substrate" as used herein may mean the exposed surface of the substrate itself or an outer surface of a predetermined layer or film formed on the substrate.

[0027] (First Embodiment) Figure 1 is a perspective view of a battery pack 100 according to an exemplary embodiment of the present invention.

[0028] Figure 2 is a perspective view showing some elements of a battery pack 100 according to an exemplary embodiment of the present invention.

[0029] In Figures 1 and 2, the battery pack 100 is shown to be defined in a vertical coordinate system defined as a first direction along the X-axis, a second direction along the Y-axis, and a third direction along the Z-axis, all of which are perpendicular to each other. However, the first, second, and third directions only need to be perpendicular to each other and are not particularly limited.

[0030] Referring to Figures 1 and 2, the battery pack 100 may include a lower case 110, battery cells 120, a center beam 130, a cross beam 116, multiple exhaust devices 140, multiple first embedding guides 151, multiple second embedding guides 153, a gasket 160, and an upper case 170. The battery pack 100 is the final form of a battery system to be installed in a mobility vehicle or the like.

[0031] The pack case 101, which corresponds to the housing of the battery pack 100, may include the lower case 110 and the upper case 170.

[0032] The lower case 110 may provide internal space 119 for mounting multiple 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 the first direction (e.g., the X-axis direction) and the second direction (e.g., the Y-axis direction), and a direction substantially perpendicular to the plate portion 110P of the lower case 110 is defined as the third direction (e.g., the Z-axis direction). The X-axis, Y-axis, and Z-axis directions may each be substantially perpendicular to one another. Unless otherwise stated, the definitions of directions are the same for the following drawings.

[0033] Multiple battery cells 120 may be arranged on a plate portion 110P of the lower case 110. The plate portion 110P can support the multiple 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 multiple battery cells 120. The lower surface of the plate portion 110P is the opposite surface of the upper surface of the plate portion 110P.

[0034] The side wall 110S can horizontally surround multiple battery cells 120. The side wall 110S can protect multiple battery cells 120 from the side. The side wall 110S may 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, and 114 may be fixed to each other by methods such as friction stir welding or spot welding, and are not particularly limited.

[0035] 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 each 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 sides of the plate portion 110P. In some embodiments, the third side wall 113 and the fourth side wall 114 may be positioned on the plate portion 110P.

[0036] In some embodiments, the first to fourth side walls 111, 112, 113, and 114 may be provided by an extrusion process. According to exemplary embodiments, the first to fourth side walls 111, 112, 113, and 114 may include internal voids, thereby reducing the weight of the side wall 110S. According to exemplary embodiments, the voids in the first to fourth side walls 111, 112, 113, and 114 may be either gas venting paths or coolant channels.

[0037] The technical idea of ​​the present invention will be described below with reference to embodiments in which each of the multiple battery cells 120 does not include a module frame. However, this is a non-limiting example and does not limit the technical idea of ​​the present invention in any sense. Based on what has been described herein, ordinary articulators of the art will also readily arrive at battery packs employing battery modules that include a module frame exposing one side edge of the battery cells.

[0038] The center beam 130 can isolate the elements mounted on the lower case 110 from each other. This allows the center beam 130 to protect the multiple battery cells 120 while simultaneously preventing unwanted short circuits between them.

[0039] 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 be in contact with the third side wall 113 and the fourth side wall 114. The center beam 130 may isolate a plurality of battery cells 120 from each other. The center beam 130 may be interposed between a plurality of battery cells 120. In some embodiments, the center beam 130 may divide the internal space 119 into two regions in a second direction (e.g., the Y-axis direction).

[0040] In some embodiments, the crossbeam 116 may be provided to divide the internal space 119 into two or more regions in a first direction (e.g., the X-axis direction). The crossbeam 116 may further isolate elements isolated by the center beam 130.

[0041] Some crossbeams 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 crossbeams 116 may extend in a second direction (e.g., the Y-axis direction) between the center beam 130 and the second side wall 112. In some embodiments, the crossbeams 116 may be provided to define a space in which a single battery cell stack or a group of battery cells are housed.

[0042] The arrangement of the center beam 130, cross beam 116, and multiple battery cells 120 disclosed in Figure 1 is a non-limiting example and does not limit the technical idea of ​​the present invention in any sense. A person of ordinary skill in the art can readily arrive at battery packs including a variety of arrangements and numbers of center beams and battery cells based on what has been described herein.

[0043] Multiple exhaust devices 140 may be coupled to the fourth side wall 114. The fourth side wall 114 may include multiple exhaust holes connected to the multiple exhaust devices 140. The multiple exhaust holes may be configured to provide a path for exhausting gases and heat from inside the battery pack 100.

[0044] Multiple exhaust devices 140 may be configured to slow down thermal propagation by releasing high-temperature gas from inside the battery pack 100 to the outside when at least one of the multiple battery cells 120 is in a thermal runway state.

[0045] Here, thermal runaway of multiple battery cells 120 is a state in which the temperature change of multiple battery cells 120 further accelerates that temperature change, resulting in an uncontrollable positive feedback loop. Multiple battery cells 120 in a thermal runaway state exhibit a rapid temperature increase and may emit large amounts of high-pressure gas and combustion residue.

[0046] Multiple first embedded guides 151 may be positioned on the side wall 110S. Multiple first embedded guides 151 may be positioned on the corners 110C of the upper surface of the side wall 110S. Multiple first embedded guides 151 may be coupled to the corners 110C of the upper surface of the side wall 110S. Multiple first embedded guides 151 may be partially embedded in the side wall 110S. Multiple first embedded guides 151 may partially protrude from the side wall 110S.

[0047] Multiple second embedding guides 153 may be positioned on the side wall 110S. Multiple second embedding guides 153 may be positioned on the upper surface of the side wall 110S. Multiple second embedding guides 153 may be interposed between the corners 110C of the side wall 110S. Multiple second embedding guides 153 may be interposed between multiple first embedding guides 151. Multiple second embedding guides 153 may be coupled to the upper surface of the side wall 110S. Multiple second embedding guides 153 may be partially embedded in the side wall 110S. Multiple second embedding guides 153 may partially protrude from the side wall 110S.

[0048] Each of the multiple first embedding guides 151 and second embedding guides 153 may contain a metallic material. Each of the multiple first embedding guides 151 and second embedding guides 153 may contain, for example, aluminum. Each of the multiple first embedding guides 151 and second embedding guides 153 may also contain, for example, steel such as carbon steel, nickel steel, chromium steel, nickel-chromium steel, and manganese steel.

[0049] The battery pack 100 may further include electrical components. In some embodiments, these electrical components may be mounted on the lower case 110. In some embodiments, these electrical components may be located between the fourth side wall 114, where the exhaust device 140 is installed, and the plurality of battery cells 120. In some embodiments, the electrical components may include any electronic elements necessary to power the battery pack.

[0050] 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 at a set location inside the battery pack 100. In some embodiments, the battery pack 100 may include measuring instruments for measuring the voltage, current, and temperature mentioned above.

[0051] Balancing the battery pack 100 is an operation to reduce deviations between multiple battery cells 120. Control of the battery pack 100 includes preventing overcharging, over-discharging, and overcurrent. Through monitoring, balancing, and control, the battery pack 100 can operate under optimal conditions, thereby preventing or reducing shortening of the lifespan of each of the multiple battery cells 120.

[0052] The above electrical components may further include a cooling system, a power relay assembly (PRA), a safety plug, and the like. The cooling system may include a cooling fan. The cooling fan can prevent each of the multiple battery cells 120 from overheating 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., the vehicle's motor). The PRA can protect the multiple battery cells 120 and the external load (e.g., the vehicle's motor) by cutting off the power supply to the external load (e.g., the vehicle's motor) in situations where abnormal voltages occur, such as a voltage surge.

[0053] The battery pack 100 may further include a plurality of busbars configured to electrically connect a plurality of battery cells 120 to each other. The plurality of battery cells 120 may be connected in series and / or parallel by the plurality of busbars. This may configure the battery pack 100 to output a high voltage to an external load (e.g., a vehicle motor).

[0054] The gasket 160 may contain a material that expands and contracts in response to applied pressure. The gasket 160 may contain rubber synthesized from a material such as EPDM (ethylene-propylene diene monomer). When the lower case 110 and the upper case 170 are joined, 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 can pressurize the gasket 160 so that it deforms slightly. This allows the battery pack 100 to be sealed and external fluids to be isolated from the internal space of the battery pack 100.

[0055] The upper case 170 may be coupled to the lower case 110. In some embodiments, the upper case 170 may include a main surface and an edge. The main surface may cover elements mounted on the battery pack 100, such as a plurality of battery cells 120 and electrical components. The edge is the surface that contacts the lower case 110. In some embodiments, the upper case 170 may have a flat plate form, in which case the edge may horizontally surround the main surface. In some embodiments, the main surface may be elevated compared to the edge, and the edge and the main surface may be connected by a curved portion.

[0056] 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 embedding guides 151 and second embedding guides 153. According to an exemplary embodiment, the battery pack 100 may further include elements coupled to the plurality of first embedding guides 151 and second embedding guides 153 for securing the upper case 170 to the side wall 110S of the lower case 110. These elements may include, but are not limited to, bolts and nuts.

[0057] Figure 3 is an enlarged perspective view showing how a battery cell 120 is installed inside a lower case 110 according to one embodiment of the present invention.

[0058] Referring to Figure 3, battery cell stacks S1, S2, ..., S6 are arranged within the regions defined by 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 contains multiple battery cells 120. Hereinafter, a battery cell stack may simply mean a collection of multiple battery cells, or it may mean an assembly of multiple battery cells housed within a particular frame.

[0059] 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 prismatic battery cell.

[0060] In some embodiments, the battery cell 120 has a thin, plate-like body and may preferably consist of a pouch cell structure. The pouch cell may consist of an electrode assembly formed by alternately stacking a positive electrode, a separator, and a negative electrode, with an electrode tab drawn out on at least one side and connected to a cell lead. The positive and negative electrodes may be manufactured by coating at least one surface of a current collector with a slurry of electrode active material, binder resin, conductive material, and other additives. As the electrode active material, in the case of the positive electrode, a conventional positive electrode active material such as a lithium-containing transition metal oxide may be used, and in the case of the negative electrode, a conventional negative electrode active material such as lithium metal, carbon material, and metal compounds or mixtures thereof, which can intercept and release lithium ions, may be used. Furthermore, as the separator, a conventional porous polymer film used in lithium secondary batteries may be used.

[0061] A standard lithium secondary battery electrolyte can be used as the electrolyte housed within the cover along with the electrode assembly. The cover is made of a sheet material and includes a storage compartment for housing the electrode assembly. Preferably, the cover is formed by joining a first case and a second case, both formed by processing the sheet material into a predetermined shape. The sheet material forming the cover has a multilayer structure in which an outermost 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 sealing material are laminated together.

[0062] The sheet material forming the cover may, if necessary, have a predetermined adhesive resin layer interposed between the internal resin layer and the metal layer, and between the external resin layer and the metal layer. The adhesive resin layer is for smooth adhesion between dissimilar materials and is formed in single or multilayer form. The material is usually a polyolefin resin, or a polyurethane resin may be used for smooth processing, and mixtures thereof can also be used.

[0063] The above-mentioned plurality of battery cells 120 may be arranged in a first direction (for example, in the 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 a first direction (for example, in the 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 a first direction (for example, in the X-axis direction).

[0064] 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., 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., 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., the Y-axis direction).

[0065] Each of the battery cell stacks S1, S2, ..., S6 is provided with a corresponding isolation sheet 184. The isolation sheet 184 can surround the bottom and a pair of sides of the battery cell stacks S1, S2, ..., S6 without interfering with the electrical connection of the battery cells 120. In some embodiments, the isolation sheet 184 can face the bottom of the battery cell stacks S1, S2, ..., S6.

[0066] The separation sheet 184 may extend horizontally over the entire or partial bottom surface of the battery cell stacks S1, S2, ..., S6, and then substantially vertically along the sides of the battery cell stacks S1, S2, ..., S6.

[0067] In some embodiments, the separation sheet 184 may extend across the bottom surface of the battery cell stacks S1, S2, ..., S6 along a first direction (e.g., the X-axis direction) and / or a second direction (e.g., the Y-axis direction), then bend at the side ends of the battery cell stacks S1, S2, ..., S6, and then extend along the sides of the battery cell stacks S1, S2, ..., S6.

[0068] In some embodiments, the separation sheet 184 may consist of two separation sheets that extend from near both ends of the bottom surface of the battery cell stack S1, S2, ..., S6 to both ends along a first direction (e.g., the X-axis direction) and / or a second direction (e.g., the Y-axis direction), and then extend along the sides of the battery cell stack S1, S2, ..., S6. This will be described in more detail later with reference to Figures 12 and 13.

[0069] Figure 4 is an exploded perspective view showing how the separation sheet 184 surrounds the bottom and a pair of sides of the first battery cell stack S1. Figure 5 is a perspective view showing how the separation sheet 184 surrounds the bottom and a pair of sides of the first battery cell stack S1. Here, the separation sheet 184 surrounds the first battery cell stack S1, but an average engineer can understand that the same configuration can be applied to the second to sixth battery cell stacks S2, S3, ..., S6.

[0070] Referring to Figures 4 and 5, the bottom surface of the first battery cell stack S1, which includes battery cells 120 stacked in a first direction (e.g., the X-axis direction), and a pair of sides perpendicular to the first direction (e.g., the X-axis direction) can face the separation sheet 184.

[0071] The separation sheet 184 described above may be made of polyethylene terephthalate, polyvinyl chloride, polystyrene, polyethylene, polyethylene naphthalate, polybutylene terephthalate, polyacetal, polyamide, polyester sulfone, polyphenylene oxide, polyphenylene sulfide, polypropylene, or copolymers thereof. However, the present invention is not limited thereto.

[0072] The separation sheet 184 may have adhesive properties on at least one surface. In some embodiments, the separation sheet 184 may be positioned so that the adhesive surface faces the pack case 101. In some embodiments, the separation sheet 184 may be positioned so that the adhesive surface faces the lower case 110. In some embodiments, the separation sheet 184 may be positioned so that the adhesive surface faces the plate portion 110P of the lower case 110. The separation sheet 184 may be bonded to the plate portion 110P by the adhesive force when it comes into contact with the plate portion 110P. In some embodiments, both sides of the separation sheet 184 may have adhesive properties.

[0073] To provide the above-mentioned adhesive strength to the separation sheet 184, the separation sheet 184 may include an adhesive layer. The adhesive layer may be any substance known in the art, such as, but is not limited to, acrylic adhesive compositions, epoxy adhesive compositions, polyolefin adhesive compositions, polyamide adhesive compositions, polyurethane adhesive compositions, or EVA adhesive compositions.

[0074] A thermally conductive resin layer 182 may be provided between the separation sheet 184 and the bottom surface of the first battery cell stack S1. The thermally conductive resin layer 182 may contain a thermally conductive resin, and more specifically, a thermally conductive adhesive. In some embodiments, the thermally conductive resin may contain one or more of silicone resins, urethane resins, or acrylic resins. However, the present invention is not limited to these, and any thermally conductive resin known in the art to which the present invention belongs may be used.

[0075] The above-mentioned thermally conductive resin is in a liquid phase when applied, but hardens after application and can play a role in fixing the separation sheet 184 and the first battery cell stack S1 to each other. Furthermore, the above-mentioned thermally conductive resin has excellent thermal conductivity properties and can quickly transfer the heat generated in the battery cell 120 to the plate portion 110P, thereby preventing overheating of the battery pack 100.

[0076] In some embodiments, the width W2 of the separation sheet 184 in the second direction (e.g., the Y-axis direction) may be smaller than the width W1 of the first battery cell stack S1. The width W3 of the thermal conductive resin layer 182 in the second direction (e.g., the Y-axis direction) may be smaller than or the same as the width W2 of the separation sheet 184 in the second direction (e.g., the Y-axis direction).

[0077] Since the width W3 of the thermal conductive resin layer 182 in the second direction (e.g., the Y-axis direction) is smaller than or equal to the width W2 of the separation sheet 184 in the second direction (e.g., the Y-axis direction), the thermal conductive resin layer 182 can be provided only between the first battery cell stack S1 and the separation sheet 184. In other words, the thermal conductive resin layer 182 can be provided so as not to contact the pack case 101. In some embodiments, one surface of the thermal conductive resin layer 182 may be in contact with the separation sheet 184, and the other surface of the thermal conductive resin layer 182 may be in contact with the bottom surface of the first battery cell stack S1.

[0078] In some embodiments, when the separation sheet 184 is extended in the third direction (e.g., the Z-axis direction), the height h2 of the separation sheet 184 in that third direction (e.g., the Z-axis direction) may be greater than the height h1 of the first battery cell stack S1. As a result, the upper end of the separation sheet 184 may extend higher than the upper surface of each battery cell stack S1, S2, ..., S6, as shown in Figure 3. However, since the separation sheet 184 is made of a flexible material, the upper end portion of the separation sheet 184 may be folded parallel to the upper surface of the battery cell stacks S1, S2, ..., S6 within the battery pack 100.

[0079] Figure 6 is a side view showing how the separation sheet 184 surrounds the bottom and a pair of sides of the first battery cell stack S1.

[0080] Referring to Figure 6, the bottom surface of the first battery cell stack S1 is one side edge of the battery cell 120 included in the first battery cell stack S1. The bottom surface of the first battery cell stack S1 faces the separation sheet 184 with the thermal conductive resin layer 182 in between.

[0081] The separation sheet 184 and the thermal conductive resin layer 182 can be bonded together with an adhesive strength of a first adhesive strength, which is the adhesive strength per unit area. The thermal conductive resin layer 182 does not come into contact with the pack case 101, but if the thermal conductive resin layer 182 were bonded to the pack case 101, and in particular to the plate portion 110P which is the bottom surface of the lower case 110, the second adhesive strength, which is the adhesive strength per unit area between them, would be even greater than the first adhesive strength. In other words, the first adhesive strength is even smaller than the second adhesive strength formed in a hypothetical situation (i.e., when the thermal conductive resin layer 182 is bonded to the plate portion 110P which is the bottom surface of the lower case 110).

[0082] In some embodiments, the first adhesive strength is approximately 15 gf / mm² when measured according to ASTM D3163 standard. 2 ~approximately 65 gf / mm2 This is possible. In some embodiments, the second adhesive strength is approximately 30 gf / mm² when measured according to ASTM D3163 standard. 2 ~approximately 90 gf / mm 2 This is possible. If the first adhesive force is too strong, it may not be easy to remove the separation sheet 184 later when needed. If the first adhesive force is too weak, the battery cell 120 may not be sufficiently secured to the battery pack 100, and the cell leads may be damaged.

[0083] In some embodiments, the first adhesive strength may be about 10% to about 70% of the second adhesive strength. In some embodiments, the first adhesive strength may be about 10% to about 70%, about 15% to about 65%, about 20% to about 60%, about 25% to about 55%, about 30% to about 50%, about 35% to about 45%, or any two of these values.

[0084] The above adhesive strength can be measured by methods such as ASTM D950, ASTM D1876, ASTM D3163, ASTM D1002, ASTM D5868, ASTM D4541, ASTM D2295, ASTM D7234, ISO 13445, and ISO 4624.

[0085] As shown in Figure 6, the separation sheet 184 may extend in a first direction (e.g., the X-axis direction) across the bottom surface of the first battery cell stack S1. Subsequently, the separation sheet 184 may extend along the side surface of the first battery cell stack S1 after being folded at the side end of the first battery cell stack S1. In some embodiments, the separation sheet 184 may extend in a third direction (e.g., the Z-axis direction) along the side surface at the side end of the first battery cell stack S1.

[0086] In Figures 4 and 6, the thermally conductive resin layer 182 is shown as a single continuous layer, but the layers may also be arranged discontinuously horizontally.

[0087] Figures 7 to 11 are conceptual diagrams illustrating a method for removing a specific battery cell stack in a battery pack 100 according to an embodiment of the present invention. Figures 7 to 11 illustrate the first battery cell stack S1, but an ordinary technician can understand that the same method may be applied to other battery cell stacks S2, S3, ..., S6.

[0088] Referring to Figure 7, the first battery cell stack S1 is located between the crossbeam 116 and the fourth side wall 114, and a separation sheet 184 and a thermally conductive resin layer 182 are provided as described in Figures 4 to 6.

[0089] The separation sheet 184 may be configured to be attachable to and detachable from the cross beam 116 and the fourth side wall 114. As described above, the separation sheet 184 may have an adhesive layer on at least one surface, and the separation sheet 184 may be positioned so that the adhesive layer faces the plate portion 110P of the lower case. The adhesive layer may also be attached to the cross beam 116 and the fourth side wall 114, and the separation sheet 184 may be detached from the cross beam 116 and the fourth side wall 114 by applying force in a suitable direction to the end portion of the separation sheet 184.

[0090] Referring to Figure 8, a force F is applied to one end of the separation sheet 184 in a direction away from the plate portion 110P. The force F is transmitted to the separation sheet 184 attached to the bottom of the first battery cell stack S1, and a predetermined shear force is generated in the horizontal direction (i.e., perpendicular to the third direction (for example, the Z-axis direction)).

[0091] Referring to Figure 9, when the force F is continuously applied, the shear force gradually increases, and when the shear force exceeds a certain critical point, the separating sheet 184 overcomes the adhesive force with the thermal conductive resin layer 182 and the adhesive force with the plate portion 110P, and begins to be pulled out to one side. That is, the separating sheet 184 begins to be pulled out in the direction in which the shear force generated by the force F applied to one end of the separating sheet 184 acts (in this case, the -X axis direction).

[0092] Referring to Figure 10, once the separation sheet 184 has begun to be pulled out, it can be further pulled out by a continuously applied force F, and finally completely removed from the surface of the first battery cell stack S1.

[0093] Referring to Figure 11, since there is a separation between the plate portion 110P and the thermally conductive resin layer 182, the first battery cell stack S1 can be easily removed from the lower case 110.

[0094] (Second Embodiment) Figure 12 is an exploded perspective view showing how a pair of separation sheets 184a and 184b according to another embodiment of the present invention surround a portion of the bottom surface and a pair of sides of the first battery cell stack S1. Figure 13 is a side view showing how the pair of separation sheets 184a and 184b surround the bottom surface and a pair of sides of the first battery cell stack S1.

[0095] Referring to Figures 12 and 13, while the embodiment shown in Figure 4 provides one separation sheet 184, this embodiment provides a pair of separation sheets, namely a first separation sheet 184a and a second separation sheet 184b.

[0096] The first separation sheet 184a may extend along one side of the first battery cell stack S1. The first separation sheet 184a may extend at least over the entire height of the first battery cell stack S1. After being folded at the lower end of the one side of the first battery cell stack S1, the first separation sheet 184a may extend to a predetermined length toward the center of the bottom surface of the first battery cell stack S1.

[0097] A first thermally conductive resin layer 182a may be provided between the bottom surface of the first battery cell stack S1 and the first separation sheet 184a. In some embodiments, the first thermally conductive resin layer 182a may be located only between the bottom surface of the first battery cell stack S1 and the first separation sheet 184a.

[0098] The second separation sheet 184b may extend along the other side of the first battery cell stack S1. The other side is the surface opposite to the one side. The second separation sheet 184b may extend at least over the entire height of the first battery cell stack S1. After being folded at the lower end of the other side of the first battery cell stack S1, the second separation sheet 184b may extend to a predetermined length toward the center of the bottom surface of the first battery cell stack S1.

[0099] A second thermally conductive resin layer 182b may be provided between the bottom surface of the first battery cell stack S1 and the second separation sheet 184b. In some embodiments, the second thermally conductive resin layer 182b may be located only between the bottom surface of the first battery cell stack S1 and the second separation sheet 184b.

[0100] In some embodiments, a thermally conductive resin layer may not be provided between the first separation sheet 184a and the second separation sheet 184b. In this case, the bottom surface of the first battery cell stack S1 can directly face the plate portion 110P (see Figure 2) between the first separation sheet 184a and the second separation sheet 184b.

[0101] Figures 14 to 16 are conceptual diagrams illustrating a method for removing a specific battery cell stack in a battery pack 100 according to another embodiment of the present invention. While Figures 14 to 16 describe a first battery cell stack S1, an ordinary technician can understand that the same method may be applied to other battery cell stacks S2, S3, ..., S6.

[0102] Referring to Figure 14, the first battery cell stack S1 is located between the crossbeam 116 and the fourth side wall 114, and a first separation sheet 184a and a second separation sheet 184b and a first thermal conductive resin layer 182a and a second thermal conductive resin layer 182b are provided as described in Figures 12 and 13.

[0103] Each of the first separation sheet 184a and the second separation sheet 184b may be configured to be able to adhere to and detach from the fourth side wall 114 and the cross beam 116. Each of the first separation sheet 184a and the second separation sheet 184b has an adhesive layer on at least one surface, and the first separation sheet 184a and the second separation sheet 184b may be arranged such that the adhesive layer faces the plate portion 110P side of the lower case. The adhesive layer may also adhere to the fourth side wall 114 and the cross beam 116, and can be detached from the fourth side wall 114 and the cross beam 116 by applying force in a suitable direction to the ends of the first separation sheet 184a and the second separation sheet 184b.

[0104] Referring to Figure 15, a force F is applied to the ends of the first separation sheet 184a and the second separation sheet 184b in a direction away from the plate portion 110P. The force F is transmitted to the first separation sheet 184a and the second separation sheet 184b, which are provided between the bottom of the first battery cell stack S1 and the plate portion 110P, and a predetermined shear force is generated in the horizontal direction (i.e., in a direction perpendicular to the third direction (for example, the Z-axis direction)).

[0105] When the above force F is continuously applied, the shear force gradually increases, and when the shear force exceeds a certain critical point, the first separating sheet 184a and the second separating sheet 184b overcome the adhesive force with the first thermal conductive resin layer 182a and the second thermal conductive resin layer 182b and the adhesive force with the plate portion 110P, and begin to be pulled out to one side. That is, the separating sheet 184 begins to be pulled out in the direction in which the shear force generated by the force F applied to one end of the first separating sheet 184a and the second separating sheet 184b acts.

[0106] Referring to Figure 16, once the first separation sheet 184a and the second separation sheet 184b have begun to be pulled out, they can be further pulled out by a continuously applied force F, and ultimately the first separation sheet 184a and the second separation sheet 184b can be removed from the space between the bottom of the first battery cell stack S1 and the plate portion 110P.

[0107] Since the first thermally conductive resin layer 182a and the second thermally conductive resin layer 182b are separated from the plate portion 110P by a distance approximately corresponding to the thickness of the separation sheet 184, the first battery cell stack S1 or a specific battery cell 120 can be removed from the lower case 110 relatively easily. In the battery pack 100 according to the embodiment of the present invention, if a specific battery cell 120 is defective, only that battery cell 120 can be selectively and easily replaced, thereby greatly improving the convenience of maintenance of the battery pack 100.

[0108] (Third embodiment) Figure 17 is an exploded perspective view showing how a separation sheet 184 according to another embodiment of the present invention surrounds the bottom surface and a pair of sides of the first battery cell stack S1.

[0109] Referring to Figure 17, the separation sheet 184 has a perforated line 185, which differs from the embodiment described with reference to Figures 4 to 11. Therefore, the following explanation will focus on these differences.

[0110] In some embodiments, the cutting lines 185 may consist of incisions that penetrate the separation sheet 184 and are arranged in a straight line at predetermined intervals. In some embodiments, the cutting lines 185 may not penetrate the separation sheet 184, but may consist of intermittent or continuous cuts to a predetermined depth.

[0111] The cut line 185 can help the separation sheet 184 break easily when a shear force is applied perpendicular or oblique to it. In particular, the separation sheet 184 can break along the cut line 185. When the separation sheet 184 breaks along the cut line 185, not only is the predictability of the break location improved, but the separation sheet 184 can be removed more quickly because a force F can be applied to both ends of the separation sheet 184, similar to the embodiments described with reference to Figures 12 to 16.

[0112] Thermally conductive resin layers 182a and 182b may be provided between the bottom surface of the first battery cell stack S1 and the separation sheet 184. In some embodiments, the first thermally conductive resin layer 182a may be provided on one side of the cut line 185, and the second thermally conductive resin layer 182b may be provided on the other side. In some embodiments, no thermally conductive resin layer may be interposed between the bottom surface of the first battery cell stack S1 and the cut line 185.

[0113] Figures 18 and 19 are conceptual diagrams illustrating a method for removing a specific battery cell stack in a battery pack 100 according to another embodiment of the present invention.

[0114] Referring to Figures 17 and 18, when a force F is applied to both ends of the separation sheet 184, a horizontal shear force is formed on the separation sheet 184 located between the bottom of the first battery cell stack S1 and the plate portion 110P. If the force F is continued to be applied, the shear force can overcome the adhesive force between the first thermal conductive resin layer 182a and the second thermal conductive resin layer 182b, the adhesive force with the plate portion 110P, and the breaking strength of the separation sheet 184 at the cut line 185. As a result, the separation sheet 184 breaks at the cut line 185 and separates into the first separation sheet 184a and the second separation sheet 184b, which are then pulled out along the lower surface of the first battery cell stack S1.

[0115] Referring to Figure 19, if a continuous force F is applied to the ends of the first separation sheet 184a and the second separation sheet 184b, the first separation sheet 184a and the second separation sheet 184b will continue to be pulled out, and ultimately the separation sheet 184 can be removed from the space between the bottom of the first battery cell stack S1 and the plate portion 110P.

[0116] Since the thermally conductive resin layer 182 is separated from the plate portion 110P by a distance approximately corresponding to the thickness of the separation sheet 184, the first battery cell stack S1 or a specific battery cell 120 can be removed from the lower case 110 relatively easily. In the battery pack 100 according to the embodiment of the present invention, if a specific battery cell 120 is defective, only that battery cell 120 can be selectively and easily replaced, thus greatly improving the convenience of maintenance of the battery pack 100.

[0117] As described above, embodiments of the present invention have been described in detail, but a person with ordinary skill in the art to which the present invention pertains can modify and implement the present invention in various ways without departing from the spirit and scope of the invention as defined in the appended claims. Accordingly, any future modifications of embodiments of the present invention will not depart from the art of the present invention. [Explanation of symbols]

[0118] 100 Battery Packs 101 Pack Case 110 Lower case 110C Corner 110P Plate Section 110S side wall 111 First side wall 112 Second side wall 113 Third side wall 114 Fourth side wall 116 Crossbeam 119 Interior space 120 battery cells 130 Center Beam 140 Exhaust system 151 First Embedding Guide 153 Second Embedding Guide 160 Gasket 170 Top Case 182 Thermally conductive resin layer 182a First thermally conductive resin layer 182b Second thermally conductive resin layer 184 Separation Sheet 184a First Separation Sheet 184b Second Separation Sheet 185 Cutting line S1 First Battery Cell Stack S2 Second Battery Cell Stack S3 Third Battery Cell Stack S4 4th Battery Cell Stack S5 5th Battery Cell Stack S6 6th Battery Cell Stack W1 width W2 width W3 width

Claims

1. A pack case including a lower case and an upper case that define the internal space. Multiple battery cells provided within the aforementioned internal space, A separation sheet provided between the bottom surface of the pack case and the plurality of battery cells, A battery pack comprising a thermally conductive resin layer provided between the separation sheet and the plurality of battery cells, The separation sheet and the thermally conductive resin layer are bonded together with a first adhesive strength, which is the adhesive strength per unit area. A battery pack in which the first adhesive strength is less than the second adhesive strength, which is the adhesive strength per unit area when the pack case and the thermally conductive resin layer are bonded together.

2. The battery pack according to claim 1, wherein the first adhesive strength is 10% to 70% of the second adhesive strength.

3. The battery pack according to claim 1, wherein the thermally conductive resin layer is provided only between the separation sheet and the plurality of battery cells.

4. The battery pack according to claim 3, wherein the thermally conductive resin layer does not come into contact with the pack case.

5. The battery pack according to any one of claims 1 to 4, wherein the separation sheet is a sheet that has adhesive force to the pack case.

6. The plurality of battery cells include one or more battery cell stacks, The surface of the battery cell stack facing the bottom surface faces the separation sheet, The battery pack according to any one of claims 1 to 4, wherein the width of the separation sheet is smaller than the width of the surface of the battery cell stack.

7. The battery pack according to claim 6, wherein the separation sheet extends along the side surface of the battery cell stack.

8. The separation sheet includes a cut line that crosses the separation sheet, The battery pack according to claim 6, wherein the cut line passes between the battery cell stack and the bottom surface.

9. The battery pack according to claim 6, wherein the thermally conductive resin layer is disposed only between the surface of the battery cell stack facing the bottom surface and the separation sheet.

10. The battery pack according to claim 9, wherein one surface of the thermally conductive resin layer is in contact with the separation sheet, and the other surface of the thermally conductive resin layer is in contact with the surface of the battery cell stack.

11. The plurality of battery cells include one or more battery cell stacks, The separation sheet includes a first separation sheet and a second separation sheet. The first separation sheet is located between the battery cell stack and the bottom surface at one end of the battery cell stack. The battery pack according to any one of claims 1 to 4, wherein the second separation sheet, separated from the first separation sheet, is located between the battery cell stack and the bottom surface on the other end side of the battery cell stack.

12. The battery pack according to claim 11, wherein the battery cell stack faces the bottom surface directly between the first separation sheet and the second separation sheet.

13. In a vertical coordinate system defined as a first direction, a second direction, and a third direction that are perpendicular to each other, Multiple battery cells stacked in the first direction, A pack case including a lower case and an upper case, which includes an internal space for housing the plurality of battery cells, A separation sheet provided between the bottom surface of the pack case and the plurality of battery cells, The separation sheet and the plurality of battery cells include a thermally conductive resin layer provided between them, A battery pack in which the separation sheet is configured to be separated from the thermally conductive resin layer by a shear force applied to the thermally conductive resin layer.

14. The battery pack according to claim 13, wherein the thermally conductive resin layer does not come into contact with the pack case.

15. The lower case includes side walls and crossbeams that cross the lower case, The battery pack according to claim 13 or 14, wherein the separation sheet is configured to be detachably attached to the side wall and / or the cross beam.

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