Easy-to-disassemble battery pack

Abstract

The present invention relates to an easily disassembled battery pack having an insulating film between a thermally conductive resin and a heat sink so that the lower part of the battery pack can be separated from the battery cell while being tightly fixed to the battery cell for heat transfer.

Description

[Technical field]

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0182832 filed on December 23, 2022, and all contents disclosed in the Korean Patent Application are incorporated herein by reference.

[0002] The present invention relates to an easily disassembled battery pack, and more particularly to an easily disassembled battery pack in which a lower portion of the battery pack is tightly fixed to a battery cell for heat transfer, but can be separated from the battery cell. [Background technology]

[0003] A secondary battery is composed of a battery module in which a plurality of battery cells are connected in series and / or parallel according to a desired output voltage or charge / discharge capacity, or a battery pack in which these are further connected.

[0004] Pouch-type batteries, in which a stack-type or stack / folding-type electrode assembly is built into a pouch-type battery case made of a laminate sheet, are also widely used in battery modules or battery packs due to advantages such as low manufacturing costs and high energy density.

[0005] A pouch-type battery is generally manufactured by forming a laminate sheet including an outer coating layer, a metal barrier layer, and an inner adhesive layer into a battery case, and then sealing the laminate sheet to manufacture the pouch-type battery.

[0006] 1, a pouch-type battery 50 has an electrode assembly 20 housed in a receiving portion 13 of a battery case 10, which is composed of a lower portion 11 and an upper portion 12. The electrode assembly 20 has a positive electrode tab 21 and a negative electrode tab 22 welded to two electrode leads 31 and 32, respectively, and is exposed to the outside of the battery case 10. A pair of insulating films 41 and 42 are disposed on the upper and lower portions of the electrode leads 31 and 32, and the outer periphery of the case 10 is sealed.

[0007] 1 illustrates a case where the positive electrode tab 21 and the negative electrode tab 22 are in the same direction. That is, in FIG. 1, the positive electrode tab 21 and the negative electrode tab 22 are only in the +x direction on a plane parallel to the yz plane of the electrode assembly 20. When the positive electrode tab 21 and the negative electrode tab 22 are in the other direction of the electrode assembly 20, that is, when they are located in the +x direction and the -x direction on a plane parallel to the yz plane of the electrode assembly 20 in FIG. 1, the folded edge of the battery case, the folded edge located on the y-axis in FIG. 1, rotates counterclockwise or clockwise to be located on the x-axis.

[0008] 2 is a perspective view of a pouch-type battery 60 with positive and negative tabs on both sides. Referring to FIG 2, the pouch-type battery or battery cell 60 includes a cell case upper part 62, a cell case lower part 61, an electrode assembly (not shown) housed inside the cell case upper part and the cell case lower part, sealing parts 65 on the edges of the cell case upper part and lower part, a pair of electrode tabs (not shown), a pair of electrode leads consisting of a positive electrode lead 66 and a negative electrode lead 67 electrically connected to the electrode tabs on one side and protruding outside the cell case on the other side, and an insulating film (not shown).

[0009] 3 is an exploded perspective view showing a schematic structure of a battery module 100 according to the related art. Referring to FIG. 3, the battery module 100 includes a pouch-type battery cell assembly 110 formed by stacking pouch-type battery cells 111 with electrode leads 112 on both sides, a bus bar frame 120 including a first vertical plate 121 and a second vertical plate 122 disposed on both sides of the pouch-type battery cell assembly 110 corresponding to the positions of the electrode leads 112 of the pouch-type battery cells 111, and an upper plate 123 connected to the first vertical plate 121 and the second vertical plate 122 and disposed on the upper part of the pouch-type battery cell assembly 110, and a mono frame 130 formed in a square tube shape so that the pouch-type battery cell assembly 110 to which the bus bar frame 120 is attached is inserted and disposed in an internal space. Here, a side frame 140 is combined with the mono frame 130 to complete the battery module 100.

[0010] In general, a battery pack is manufactured by forming a battery module from a number of battery cells, and then connecting a number of the battery modules to manufacture the battery pack. After the battery cells are manufactured, a separate manufacturer or a separate assembly line manufactures the battery modules, which are then assembled into a battery pack. In addition, the battery module has an individual case for its own insulation and safety, which takes up space and increases its weight.

[0011] Recently, in order to maximize the efficiency and energy of the assembly process, a simplified battery module in which a part of the battery cell is exposed or a battery cell is directly assembled to a battery pack, CTP (cell to pack), is applied. In order to quickly transfer heat released from the battery module and / or battery pack during charging and discharging, a heat sink is provided at the bottom of the battery module and / or battery pack. In such a battery module and / or battery pack, a thermal resin is used for heat conduction and adhesive purposes to adhere the battery cell to the heat sink and to fix the battery cell. Although the surface area in contact with the battery cell increases due to perfect adhesion, it is very difficult to separate the battery cell from the battery module and / or battery pack because the battery cell is fixed to the bottom of the battery pack. Since the thermal conductive resin is hardened after adhesion, it is virtually impossible to separate the battery cell in a complete state in the case of a pouch-type battery cell.

[0012] Fig. 4 is an example of a CTP, and is a perspective view of a battery pack 200 with the top plate removed, and Fig. 5 is a perspective view of a battery cell stack 220 used in the battery pack 200 of Fig. 4. As shown in Fig. 5, a number of battery cells 210 are stacked to form a battery cell stack 220, which is arranged inside a pack frame 240. Although two battery cell stacks 220 are arranged in Fig. 4, this can be changed as necessary.

[0013] 6 is a perspective view of a simplified battery module 300 according to the prior art. A module frame 250 and a bus bar case 255 surround the battery cell stack 220. Inside the bus bar case 255, the leads of the battery cells and the bus bars are connected.

[0014] Fig. 7 is a diagram showing only a portion E of a vertical cross section taken along line A-A' in Fig. 4. The xz coordinates in Fig. 4 and the xz coordinates in Fig. 7 are the same. Referring to Fig. 7, a battery cell 210, in particular a number of pouch-type battery cells standing vertically z, are stacked in a horizontal direction x. The lower portion of the battery cell 210 is fixed to a heat sink 280 by using a thermally conductive resin 260 for thermal conduction and adhesive purposes.

[0015] FIG. 8 is a diagram showing a simplified battery module 300 according to the prior art in the format of FIG. 7. The xz coordinates in FIG. 6 and FIG. 8 are the same. a) is a vertical cross section taken along the line A-A' in FIG. 6, and b) is a vertical cross section taken along the line B-B' in FIG. 6. In FIG. 8, as in FIG. 7, the battery cell 210 is surrounded by the module frame 250. In a) where the module frame 250 extends to the bottom, a thermally conductive resin 260 is disposed between the battery cell 210 and the module frame 250 to fix them together, and a thermally conductive pad 270 and a heat sink 280 are disposed below the module frame 250. In b) where the module frame 250 is only on the side, the bottom is fixed to the heat sink 280 by using the thermally conductive resin 260 for thermal conduction and adhesive purposes. This makes it difficult to separate the simplified battery module 300, as in FIG. 7.

[0016] Patent Document 1 relates to a battery module, a battery pack including such a battery module, and an automobile including such a battery pack. The battery module according to Patent Document 1 includes at least one battery cell, a module case that houses the at least one battery cell, a heat sink that is attached to one side of the module case and cools the at least one battery cell, and a foam member that is provided between the heat sink and the at least one battery cell and is arranged in contact with one side of the at least one battery cell.

[0017] Patent Document 1 needs to be improved in the following respects. 1) The contact area is very important for heat conduction. If the heat transfer medium does not directly contact the heat source, an air layer is formed in between, and since the air layer is a material with very low thermal conductivity, the heat transfer efficiency drops sharply. As shown in FIG. 6, the foam member must be thick enough to contact all parts of the irregular shape at the bottom of the pouch-type battery cell 210. When the foam member becomes thick, the length of the heat transfer increases, which is a factor in reducing the efficiency of heat transfer. Recently, due to these problems, foam members are not applied to irregular shapes, and in the case of flat surfaces, for example, foam members are applied to the sides of pouch-type battery cells.

[0018] 2) Even if a thick material is used, the foam member can only deform and contact all parts if it is pressed continuously at a certain pressure or more. If there is no pressure, the contact area decreases due to the foam member's restoring force. Therefore, in a CTP, the battery cell stack must be pressed at a certain pressure or more, and a means for maintaining this pressure must be provided. In a CTP where assembly up to the top plate is complete, if a space is created between the top plate and the battery cell stack, there will be no pressure to press or the pressure will not be to the desired extent, and the efficiency of heat transfer will drop sharply.

[0019] 3) Even if the foam material is pressed with a desired pressure or more and comes into contact with all parts, there is a difference in the degree of compression of the foam material in each part. Because it is an unformed shape, some parts are heavily compressed and other parts are insufficiently compressed. This causes density differences in each part and the thermal conductivity efficiency is not uniform. Because the microstructure of the foam pad itself is porous, the thermal conductivity efficiency may actually decrease in the insufficiently compressed parts. If the thermal conductivity efficiency of the part that generates a lot of heat is lower than other parts, the localized heat island effect increases the probability of a fire breaking out. In the case of CTP for energy maximization, the voltage is very high because one battery cell stack may be connected in series, and the amount of heat generated is also much higher than that of a conventional battery cell stack. The localized heat island effect can lead to a very dangerous situation.

[0020] In Patent Document 1, a foam member can be impregnated with a thermally conductive resin for use, but even in this case, the foam member still has the fundamental disadvantages.

[0021] Patent Document 2 relates to a cooling structure for a battery. In Patent Document 2, the cooling surface 14a of a battery module 13, which is a stack of multiple battery cells 14, is supported on a cooling plate 12, and the heat of the battery module 13 is transferred from the cooling surface 14a to the cooling plate 12, thereby cooling the battery cells. A non-conductive insulating sheet 22 is disposed between the cooling surface 14a of the battery module 13 and the cooling plate 12. Patent Document 2 does not recognize the contact area, which is recognized as a problem in Patent Document 1, and therefore the configuration is not suitable for CTP for maximizing energy. Patent Document 2 takes into consideration the cooling surface, and only flat contact.

[0022] Patent Document 3 relates to a battery module that ensures insulation performance and a battery pack including the same, which includes a battery cell stack in which a plurality of battery cells are stacked, a module frame that houses the battery cell stack, and first and second thermally conductive resin layers that are spaced apart from each other and are formed between a bottom of the module frame and the battery cell stack, and a first insulating coating layer is formed between the first thermally conductive resin layer and the second thermally conductive resin layer.

[0023] Patent Document 3 focuses on insulation performance, and attempts to ensure insulation performance by forming a thermally conductive resin layer on the bottom of the module frame and forming an insulating coating layer on the parts where the thermally conductive resin layer is not formed, i.e., the parts where resin is not applied. Patent Document 3 is applied to a normal battery module as shown in FIG. 2, and is similar to the configuration in FIG. 7. Patent Document 3 does not solve the problem of the present invention because it is difficult to separate the module case and the battery cell stack due to the part where the thermally conductive resin layer is formed on the bottom of the module frame. In addition, multiple resin layers are formed and there is a lot of heat conductive medium, so it is not suitable for products that generate a lot of heat.

[0024] Patent Document 4 relates to a composite sheet and a battery pack using the same. Patent Document 4 includes a thermally conductive sheet and a multi-layered insulating sheet. Since Patent Document 4 includes an area with excellent thermal conductivity and an area with excellent insulation, it is not suitable for CTP for maximizing energy.

[0025] Patent Document 5 relates to a battery module and a battery pack including the same. Patent Document 5 includes a battery cell stack in which a plurality of battery cells are stacked, a module frame that houses the battery cell stack, a thermally conductive resin layer located between the lower surface of the module frame and the battery cell stack, and a first adhesive layer located between adjacent battery cells among the plurality of battery cells, and a liquid injection hole for injecting thermally conductive resin is formed on the lower surface of the module frame, and the first adhesive layer is formed adjacent to the thermally conductive resin layer. Patent Document 5 has the same configuration as FIG. 7 and is not suitable for CTP for energy maximization.

[0026] In this way, in a simplified battery module in which a portion of the battery cell is exposed in order to maximize the efficiency and energy of the assembly process, or in a cell to pack (CTP) process in which battery cells are directly assembled into a battery pack, there has yet to be provided a configuration that 1) provides uniform heat conduction efficiency by contacting the entire surface of the amorphous battery cell with uniform density, 2) does not require the application of additional pressure to contact the surface of the amorphous battery cell, 3) minimizes the distance to the heat sink while maintaining the above conditions, 4) maintains insulation performance even with a minimum thickness, and 5) allows the entire battery cell stack to be easily separated from the battery pack. [Prior art documents] [Patent documents]

[0027] [Patent Document 1] Korean Patent Publication No. 10-2017-0107800 [Patent Document 2] JP 2013-122818 A [Patent Document 3] Korean Patent Publication No. 10-2021-0120558 [Patent Document 4] Patent No. 6982738 [Patent Document 5] Korean Patent Publication No. 10-2021-0058109 Summary of the Invention [Problem to be solved by the invention]

[0028] The present invention has been made to solve the above problems, and aims to provide a configuration in a simplified battery module in which battery cells are partially exposed in order to maximize the efficiency and energy of the assembly process, or in a cell to pack (CTP) process in which battery cells are directly assembled into a battery pack, which 1) provides uniform heat conduction efficiency by contacting the entire surface of the amorphous battery cells with uniform density, 2) does not require the application of additional pressure to contact the surface of the amorphous battery cells, 3) minimizes the distance to the heat sink while maintaining the above conditions, 4) maintains insulation performance even with a minimum thickness, and 5) allows the entire battery cell stack to be easily separated from the battery pack. [Means for solving the problem]

[0029] The present invention has been made to solve the above problems, and provides a battery pack including a battery cell stack including one or more battery cells, a heat transfer part that directly contacts the battery cells of the battery cell stack to transfer heat, and a heat sink that faces the heat transfer part and releases the heat to the outside, wherein an insulating film is disposed between the heat transfer part and the heat sink, and the heat transfer part includes a thermally conductive resin.

[0030] The heat transfer part may further include a material such as carbon nanotubes that can improve thermal conductivity in addition to the thermally conductive resin. The additional material improves thermal conductivity, but preferably has low electrical conductivity.

[0031] The thermally conductive resin may be bonded to at least one surface of the battery cell stack, and more specifically, the thermally conductive resin may be bonded to a lower surface of the battery cell stack. The thermally conductive resin may also be bonded to an upper surface of the cell stack. In this case, an insulating film may be disposed on the upper surface of the thermally conductive resin, and a heat sink may be disposed on the upper surface of the insulating film.

[0032] The thermally conductive resin may be adhered to the entire lower surface of the battery cell stack, and an outermost portion of the lower surface of the battery cell stack to which the thermally conductive resin is adhered may be flat.

[0033] The insulating film faces the heat transfer part and the heat sink, respectively, and only one of the surfaces may be bonded to the heat transfer part. Specifically, the insulating film may be bonded only to the heat transfer part.

[0034] The thermally conductive resin is a liquid adhesive, and may be one or more of a urethane type, a silicone type, an acrylic type, and an epoxy type.

[0035] The insulating film may be a film containing one or more of PET, PE, and urethane materials.

[0036] The battery cell may be one of a cylindrical battery cell, a prismatic battery cell, and a pouch battery cell.

[0037] The battery pack may be a cell to pack (CTP) in which battery cells are directly assembled into a battery pack, or a simplified battery module in which some of the cells are exposed.

[0038] The present invention can also provide a combination of solutions to the above problems. Effect of the Invention

[0039] The present invention relates to a simplified battery module in which a part of a battery cell is exposed in order to maximize the efficiency and energy of the assembly process, or a CTP (cell to pack) in which a battery cell is directly assembled into a battery pack. 1) It provides uniform heat transfer efficiency by contacting the entire surface of the amorphous battery cell with uniform density. 2) There is no need to apply additional pressure to contact the surface of the non-uniform battery cells. Even if a gap is generated between the upper plate and the battery cell stack in a CTP where the upper plate is already assembled, there is no problem with the efficiency of heat transfer. 3) While maintaining the above conditions, the distance between the heat sink can be minimized to reduce the size and improve the heat transfer efficiency. 4) Even with a minimum thickness, the insulating performance between the battery cell stack and the pack frame and pack plate can be maintained. 5) The battery cell stack can be easily separated from the battery pack as a whole without being damaged, making future repairs and maintenance very easy. [Brief description of the drawings]

[0040] [Figure 1] FIG. 1 is an exploded perspective view of a pouch-type battery according to the prior art. [Diagram 2] FIG. 1 is an exploded perspective view showing a schematic structure of a battery module according to the prior art; [Diagram 3] FIG. 2 is a perspective view of a pouch-type battery having positive and negative electrode tabs located on either side. [Figure 4] FIG. 2 is a perspective view of a battery pack with the top plate removed as an example of a CTP. [Diagram 5] FIG. 5 is a perspective view of a battery cell stack used in the battery pack of FIG. 4. [Figure 6] FIG. 1 is a perspective view of a simplified battery module according to the prior art. [Figure 7] FIG. 5 is a diagram showing only a part of a vertical cross section taken along line AA' in FIG. [Figure 8] FIG. 7 is a diagram showing a battery module according to the prior art in the form shown in FIG. 6. [Figure 9] FIG. 2 shows only a portion of a vertical cross section of a CTP according to the present invention. [Figure 10] FIG. 2 shows only a portion of a vertical cross-section of a CTP according to the present invention, separated from a heat sink. [Figure 11]FIG. 2 is a cross-sectional view of a simplified battery module according to the present invention. [Figure 12] FIG. 2 is a schematic diagram of application of a thermally conductive resin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will enable those skilled in the art to easily carry out the present invention. However, in describing the operation principle of the preferred embodiments of the present invention in detail, detailed descriptions of related well-known functions or configurations will be omitted if it is determined that such detailed descriptions may unnecessarily obscure the gist of the present invention.

[0042] In addition, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only the case where the part is directly connected to another part, but also the case where the part is indirectly connected via another element between the two parts. In addition, when a part includes a certain component, it does not mean that the other component is excluded, but that the part may further include the other component, unless otherwise specified.

[0043] In addition, in this specification, limitations or additions to a certain embodiment are not only applicable to the specific embodiment, but are equally applicable to all embodiments described in this specification.

[0044] Furthermore, throughout the description of the present invention and the claims, the singular includes the plural unless otherwise stated.

[0045] In addition, throughout the description of the present invention and the claims, unless otherwise stated, "or" includes "and." Therefore, "including A or B" means three cases: including A, including B, or including both A and B.

[0046] Furthermore, all numerical ranges include both end values ​​and all intermediate values ​​therebetween unless expressly stated to exclude.

[0047] The invention will now be explained with reference to the drawings and in conjunction with detailed embodiments.

[0048] 3 is a perspective view of a pouch-type battery with positive and negative tabs on both sides. Referring to FIG. 3, a pouch-type battery or battery cell 60 includes a cell case upper part 62, a cell case lower part 61, an electrode assembly (not shown) housed inside the cell case upper and lower parts, sealing parts 65 on the edges of the cell case upper and lower parts, a pair of electrode tabs (not shown), a pair of electrode leads consisting of a positive electrode lead 66 and a negative electrode lead 67 electrically connected to the electrode tabs on one side and protruding outside the cell case on the other side, and an insulating film (not shown).

[0049] In detail, the cell case upper part 62 and the cell case lower part 61 are provided with a pocket-like space so as to accommodate the electrode assembly.

[0050] These cell cases use laminate sheets consisting of an outer coating layer, a metal layer, and an inner coating layer to form a cavity capable of housing the electrode assembly.

[0051] Since the inner coating layer is in direct contact with the electrode assembly, it must have insulating properties and electrolytic resistance, and must have sealing properties to seal against the outside, i.e., the sealing parts where the inner layers are thermally bonded together must have excellent adhesive strength.

[0052] Materials for such an inner coating layer can be selected from polyolefin resins such as polypropylene, polyethylene, polyethylene acrylate, and polybutylene, which have excellent chemical resistance and good sealing properties, polyurethane resins, and polyimide resins, but are not limited thereto. Polypropylene is preferred, which has excellent mechanical properties such as tensile strength, rigidity, surface hardness, and impact strength, as well as chemical resistance.

[0053] The metal layer in contact with the internal coating layer corresponds to a barrier layer that prevents moisture and various gases from penetrating into the inside of the battery from the outside. A suitable material for such a metal layer is an aluminum thin film, which is lightweight yet has excellent formability.

[0054] The outer surface of the metal layer is provided with an outer coating layer, and the outer coating layer may be made of a heat-resistant polymer having excellent tensile strength, moisture permeability, and air permeability so as to ensure heat resistance and chemical resistance while protecting the electrode assembly, such as, but not limited to, nylon or polyethylene terephthalate.

[0055] The electrode assemblies housed inside the cell case upper part 62 and the cell case lower part 61 may be classified into a stack type electrode assembly in which a plurality of electrodes are stacked; a jelly roll type electrode assembly in which a separator is interposed between a positive electrode and a negative electrode and the electrode is wound up; a lamination / stack type electrode assembly in which a plurality of unit cells are stacked; and a stack / folding type electrode assembly in which a unit cell is positioned on a separator sheet and the electrode is wound up.

[0056] A unit cell is prepared to manufacture the lamination / stack type electrode assembly and the stack / folding type electrode assembly, where the unit cell may be a mono-cell having a separator interposed between a positive electrode and a negative electrode, or a bi-cell having a positive electrode, a negative electrode, and a positive electrode, or a negative electrode, a positive electrode, and a negative electrode, stacked together, with a separator interposed between the positive electrode and the negative electrode.

[0057] The electrode assembly according to the present invention may have a structure in which anode / separator / cathode / separator / anode are stacked. In addition, it goes without saying that the number of cathodes and anodes constituting the electrode assembly may be freely set and used. Also, a lamination / stack type electrode assembly in which a plurality of unit cells are laminated may be used. The electrode assembly structure is applicable to all electrode assemblies described in this specification.

[0058] The positive and negative electrodes of the electrode assembly have a positive tab and a negative tab, respectively, and these pairs of tabs are connected to the positive electrode lead 66 and the negative electrode lead 67, respectively, by spot welding or the like and are arranged to protrude a predetermined length outside the cell case.

[0059] The insulating film is located on the upper and lower surfaces of the pair of electrode leads, more specifically, on a sealing portion 65 where the cell case upper portion 62 and the cell case lower portion 61 are heat-sealed. The insulating film prevents electricity generated in the electrode assembly from flowing to the cell case via the electrode leads and maintains a sealed state between the electrode leads and the cell case. The insulating film is preferably made of a non-conductive material that does not allow electricity to pass through it well, and generally, insulating tape that is relatively thin and can be easily attached to the electrode leads is often used, but is not limited thereto.

[0060] Pouch-type batteries, in which electrode tabs are located on both sides of an electrode assembly, are often used in battery modules or battery packs. A pouch-type battery cell assembly is constructed in which a plurality of pouch-type batteries, each having a positive electrode tab and a negative electrode tab on one side, are vertically arranged, and bus bars are disposed on both ends of the pouch-type battery cell assembly to electrically connect the positive electrode tabs and negative electrode tabs, more specifically, the positive electrode lead and the negative electrode lead. The bus bars disposed on both ends of the pouch-type battery cell assembly may be electrically connected to each other.

[0061] FIG. 9 is a view showing only a part of a vertical cross section of a CTP according to the present invention. The battery cell stack according to the present invention is the same as the battery cell stack used in a battery module or battery pack according to the prior art, and is also the same as FIG. 5. Referring to FIGS. 4, 5 and 9, the CTP according to the present invention is a CTP (cell to pack) in which a battery cell including a battery cell stack 220 including one or more battery cells 210, a thermally conductive resin 260 that directly contacts the battery cell 210 of the battery cell stack 220 to transfer heat, and a heat sink 280 that faces the thermally conductive resin 260 to release the heat to the outside is directly assembled into a battery pack, and an insulating film 290 is disposed between the thermally conductive resin 260 and the heat sink 280. FIG. 9 is a view illustrating a case where the heat transfer part is the thermally conductive resin 260 as an embodiment.

[0062] The thermally conductive resin 260 is adhered to at least one surface of the battery cell stack 220 , specifically, to the lower surface of the battery cell stack 220 .

[0063] The thermally conductive resin is a liquid adhesive that has a similar thermal conductivity to conventional foam pads because the thermally conductive resin can be manufactured using the same or similar materials as those used in the foam pads. The use of a liquid adhesive allows it to fill all of the irregular areas on the underside of the battery cell stack without any gaps.

[0064] The liquid adhesive may take about 24 hours or 48 hours to completely harden. This is the time it takes to completely harden, and it takes 2 to 8 hours to harden to a degree that it can maintain its initial shape. In the case of some products, it can be completely hardened after 2 to 8 hours.

[0065] The thermally conductive resin 260 is adhered to the entire lower surface of the battery cell stack 220, and the outermost portion of the lower surface of the battery cell stack 220 to which the thermally conductive resin 260 is adhered has a flat shape.

[0066] When a liquid adhesive is used for the battery cell stack, the preferred viscosity range is 150 cP to 300 cP. In order to form the bottom surface to which the thermally conductive resin is adhered into a flat shape, the following methods can be used: 1) placing an insulating film on a flat bottom, applying a liquid adhesive thereon, and then placing the battery cell stack on top and pressing, or 2) applying a liquid adhesive only to the portion of the battery cell stack that will contact the bottom in its amorphous form, and then covering it with an insulating film and placing it on the flat bottom.

[0067] Although the present invention has been described based on a pouch-type battery cell, the present invention is not limited to pouch-type battery cells, and can be applied to both cylindrical and rectangular battery cells.

[0068] In order to reduce the thickness of the thermally conductive resin, a planar shape can be formed from the lowest protruding portion of the unshaped portion of the battery cell stack to the outermost side. If a large amount of liquid adhesive is used at once, the liquid adhesive may flow before taking a shape, so it is possible to adjust the amount of liquid adhesive or to adopt a method of completing the shape after the liquid adhesive is partially cured.

[0069] 12 is a schematic diagram of application of thermally conductive resin. Thermally conductive resin 260 is applied from the lowest protruding portion to the outermost portion of the battery cell stack, specifically, the irregular portion of an individual battery cell 210. Here, the applied thickness of thermally conductive resin 260 corresponding to the lowest protruding portion is D.

[0070] Typically, the thickness of the adhesive applied is 0.5 mm to 3.0 mm, but is not limited thereto. In the case of pouch-type battery cells, the lower part of each individual battery cell is bulged at the center, so the thickness of the adhesive applied can be changed to fill all of the irregular space caused by this shape. Referring to FIG. 9, a battery cell 210, in particular a number of pouch-type battery cells standing vertically (z) are stacked in the horizontal direction x. Since the battery cells are not completely in contact with each other, it is not necessary to fill all of the non-contact gaps with adhesive. It can also be seen from FIG. 12 that some of the spaces between the battery cells are filled with adhesive.

[0071] The lower surface of the battery cell stack may be flat, but it is not limited thereto. A thermally conductive resin is attached to the lower surface of the battery cell stack, thereby forming the outermost part of the lower surface of the battery cell stack into a flat shape. The thermally conductive resin also fills the irregular outer surface and spaces of the battery cell stack or the battery. An insulating film 290 is attached thereto. The flat heat sink 280 faces the lower part of the insulating film 290, so that they face each other smoothly. In addition, since the insulating film 290 has no adhesiveness or adhesion, it can be easily separated from the heat sink 280 based on the insulating film 290 for future separation. FIG. 10 shows only a portion of a vertical cross section of the CTP according to the present invention, showing a state in which it has been separated from the heat sink 280.

[0072] The insulating film 290 faces the thermally conductive resin 260 and the heat sink 280, respectively, and is bonded to only one surface of the thermally conductive resin 260 and the heat sink 280. Specifically, the insulating film 290 is bonded only to the thermally conductive resin 260. Although only the thermally conductive resin 260 is shown here, this is an example of the heat transfer part according to the present invention. The heat transfer part according to the present invention includes a thermally conductive resin, and may be made of only the thermally conductive resin or may further include another thermally conductive material in addition to the thermally conductive resin.

[0073] The thermally conductive resin 260 is a liquid adhesive, and is one or more of urethane, silicone, acrylic, and epoxy. Silicone-based curing agents may generate siloxane, so they are not suitable for products such as automobiles. The preferred liquid adhesive is urethane-based, which not only has basic insulating properties but can also be used in the enclosed space of an automobile. In addition, urethane-based adhesives have high adhesive strength and high thermal conductivity. To further increase the thermal conductivity, metal particles with high thermal conductivity can be added to the liquid adhesive.

[0074] The insulating film 290 is a film containing one or more of PET, PE, and urethane materials. The insulating film may be a thin film and may contain one or more of PET, PE, and urethane materials. Since urethane materials are insulating materials, the insulating film is preferably a film of urethane material, but is not limited thereto. Since the thickness of the film is substantially thinner than the thickness of the thermally conductive resin and there is no significant difference in the thermal conductivity of the insulating film, an insulating film having a thickness of 0.5 mm or less, preferably 0.2 mm or less, and more preferably 0.1 mm, does not have a significant effect on thermal conduction.

[0075] Alternatively, an adhesive pad with a film already attached to the outside can be used. The adhesive pad can be attached directly to the battery cell stack. However, it is preferable that the adhesive pad is applied to the bottom of the flat surface.

[0076] FIG. 11 is a cross-sectional view of a simplified battery module according to the present invention. FIG. 11 is an improvement of FIG. 8. The configurations of the thermally conductive resin 260, the insulating film 290, and the heat sink 280 and their coupling relationships are the same as those of FIG. 9, FIG. 10, and FIG. 12, so only the differences will be described. a) and b) are vertical cross sections taken along the line A-A' as in FIG. 8, and b) is a vertical cross section taken along the line B-B'. In a) where the module frame 250 is provided down to the bottom, the thermally conductive pad 27 is provided between the battery cell 210 and the module frame 250, so that they can be separated in the future. The thermally conductive resin 260, the insulating film 290, and the heat sink 280 are provided below. In b) where the module frame 250 is provided only on the side, the battery cell 210 and the insulating film 290 are attached to each other by using the thermally conductive resin 260 for heat conduction and adhesive purposes. A flat heat sink 280 faces the lower part of the insulating film 290, and the heat sink 280 can be easily separated by the insulating film 290.

[0077] Those skilled in the art will appreciate that various applications and modifications within the scope of the present invention will be possible based on the above content. [Explanation of symbols]

[0078] 10 Battery case 11, 61 Lower 12, 62 Upper 13 Storage unit 20 Electrode assembly 21, 22 Electrode tabs 31, 32, 66, 67 Electrode leads 41, 42 Insulating film 50, 60 Pouch type battery 65 Sealing part 100 Battery Module 110 Cell Assembly 111 Pouch-type battery 112 Electrode Lead 120 Busbar Frame 121, 122 vertical plate 123 Upper Board 126 Busbar 130 Monoframe 140 Side Frame 200 CTP 210 Battery Cell 220 Battery cell stack 240 Pack Frame 250 module frame 255 Busbar case 260 Thermally conductive resin 270 Thermally conductive pad 280 Heatsink 290 Insulating Film 300 Simplified battery module D Thermal conductive resin coating thickness E Partially selected

Claims

1. a battery cell stack including one or more battery cells; a heat transfer portion that is in direct contact with the battery cells of the battery cell stack and transfers heat thereto; a heat sink facing the heat transfer portion and dissipating the heat to the outside; A battery pack comprising: An insulating film is disposed between the heat transfer part and the heat sink, The heat transfer portion of the battery pack includes a heat conductive resin.

2. The battery pack according to claim 1 , wherein the thermally conductive resin is bonded to at least one surface of the battery cell stack.

3. The battery pack according to claim 2 , wherein the thermally conductive resin is bonded to a lower surface of the battery cell stack.

4. the thermally conductive resin is bonded to the entire lower surface of the battery cell stack; The battery pack according to claim 3 , wherein an outermost portion of the lower surface of the battery cell stack to which the thermally conductive resin is adhered is flat.

5. The battery pack according to claim 1 , wherein the insulating film faces the heat transfer part and the heat sink, respectively, and only one surface of the insulating film is bonded to the heat transfer part and the heat sink.

6. The battery pack according to claim 5 , wherein the insulating film is adhered only to the heat transfer portion.

7. The battery pack according to claim 1 , wherein the thermally conductive resin is a liquid adhesive and is one or more of a urethane type, a silicone type, an acrylic type, and an epoxy type.

8. The battery pack according to claim 1 , wherein the insulating film is a film containing one or more of PET, PE, and urethane materials.

9. The battery pack according to claim 1 , wherein the battery cells are one of cylindrical battery cells, prismatic battery cells, and pouch battery cells.

10. The battery pack according to claim 1 , wherein the battery pack is a cell to pack (CTP) battery pack in which battery cells are directly assembled into a battery pack, or a battery module in which a part of a cell is exposed.

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