Battery pack

Abstract

The present technology relates to a battery pack. The battery pack according to the present invention comprises: a battery module; a lower pack case having an accommodating space in which the battery module is mounted; and an upper cover coupled to an upper portion of the lower pack case to cover the accommodation space, in which the upper cover includes: a first upper cover facing the battery module; and a second upper cover at least partially spaced apart from the first upper cover such that the insulating layer is located between the first upper cover and the second upper cover.

Description

Technical Field

[0001] The present invention relates to a battery pack having an upper cover with a heat insulation layer.

[0002] This application claims priority based on Korean Patent Application No. 10-2023-0028170 filed on March 3, 2023, the entire contents of which are incorporated herein by reference. Background Art

[0003] Recently, rechargeable secondary batteries have been widely used as energy sources for wireless mobile devices. In addition, secondary batteries have attracted attention as energy sources for electric vehicles, hybrid vehicles, etc., which are proposed as solutions to air pollution caused by existing gasoline vehicles and diesel vehicles using fossil fuels.

[0004] Two or three battery cells are arranged in a secondary battery used in a small device, but a battery module in which a plurality of battery cells are electrically connected is used in a secondary battery used in a medium or large device such as a vehicle. In addition, a battery pack in which a plurality of battery modules are electrically connected may be used.

[0005] The battery cell is manufactured by accommodating an electrode assembly in which a positive electrode, a negative electrode and a separator are stacked and an electrolyte in a case. The battery cell can be divided into a cylindrical battery cell, a square battery cell and a pouch-type battery cell according to the shape of the case.

[0006] A battery cell may be repeatedly charged and discharged through electrochemical reactions between its components. However, the temperature of the battery cell may increase abnormally due to overcharging and discharging of the battery cell or defects in the battery cell. When the temperature of the battery cell is not properly adjusted, the battery cell may burst and high-temperature gas may be generated. In addition, in this case, the temperature of adjacent battery cells may increase, resulting in continuous explosions. In order to prevent this problem, exhaust holes may be formed on the upper portion of a battery module that accommodates a plurality of battery cells. When the internal temperature of the battery module increases excessively, the high-temperature gas may be discharged through the exhaust holes on the upper portion of the battery module.

[0007] Figure 1 is a cross-sectional view illustrating a cross section of a battery pack 10 of the related art, and Figure 2 yes Figure 1 Magnified view of area A.

[0008] like Figure 1 As shown, the battery pack 10 includes a lower pack case 11 for accommodating the battery module 1 and an upper cover 12 covering the lower pack case 11 .

[0009] The battery pack 10 may be installed at the bottom of the vehicle. As described above, when the high temperature gas F is discharged from the upper part of the battery module 1, the high temperature heat may be transferred to the passengers in the vehicle. In order to prevent this problem, Figure 1 and Figure 2 As shown in FIG. 1 , in the battery pack 10 of the related art, the heat-resistant member 13 is attached to the inner side of the upper cover 12. The heat-resistant member 13 may be a heat-resistant block or a heat-resistant sheet formed of a heat-resistant material. Alternatively, the heat-resistant member 13 may be a heat-resistant layer formed on the inner surface of the upper cover 12 using a heat-resistant resin. However, as shown in FIG. Figure 2 As shown, the heat-resistant member 13 may expand or melt due to the high-temperature gas, thereby sagging below the heat-resistant member 13 toward the battery module 1, thereby blocking the exhaust holes 1a in the battery module 1. In this case, the battery cells or the battery module 1 may explode due to failure to exhaust the high-temperature gas from the inside of the battery module 1 and rapid heat transfer between adjacent battery cells.

[0010] Therefore, it is necessary to develop a technology for preventing the exhaust hole 1 a from being blocked by the heat-resistant member (also called fire-resistant member) 13 .

[0011] [Prior art literature]

[0012] (Patent Document 1) Korean Registered Patent Publication No. 10-0852727 Summary of the invention

[0013] Technical issues

[0014] In order to solve the above problems, the present invention is directed to providing a battery pack having an upper cover that can effectively block high-temperature heat transferred toward the upper portion of the battery pack without blocking exhaust holes in a battery module even in the event of thermal runaway.

[0015] Technical Solution

[0016] One aspect of the present invention provides a battery pack, comprising: a battery module; a lower battery pack housing having a accommodating space in which the battery module is installed; and an upper cover connected to an upper portion of the lower battery pack housing to cover the accommodating space, wherein the upper cover comprises: a first upper cover facing the battery module; and a second upper cover, at least a portion of which is spaced apart from the first upper cover to form an insulation layer between the first upper cover and the second upper cover.

[0017] The first upper cover and the battery module may be spaced apart from each other, and a lower surface of the first upper cover may face an upper surface of the battery module.

[0018] The second upper cover may be provided with a plurality of upper discharge holes for communication between the heat insulating layer and the outside.

[0019] The second upper cover may include an upper discharge member configured to close the upper discharge hole to hermetically seal the heat insulation layer, and to break for communication between the heat insulation layer and the outside when an inner temperature of the heat insulation layer increases by a predetermined temperature.

[0020] The second upper cover may include: an upper plate spaced apart from the first upper cover; and a partition plate connected to ends of the upper plate in a width direction and bent from the upper plate toward the first upper cover to divide the heat insulating layer into several parts.

[0021] The lower battery pack case may include: a bottom case configured to support a bottom surface of the battery module; and a cross beam configured to divide the accommodation space into several parts and support a side of the battery module, and the cross beam may be coupled to the upper cover.

[0022] The thickness of the first upper cover may be different from the thickness of the second upper cover.

[0023] The lower battery pack housing may include a bottom housing configured to support the lower surface of the battery module and a side wall housing installed along the periphery of the bottom housing. Each of the side wall housings may include an inner hollow channel and a side wall communication hole, and the side wall communication hole may be provided in a surface of the side wall housing facing the accommodation space for communication between the accommodation space and the inner hollow channel.

[0024] The battery pack may further include a heat insulating member located on the heat insulating layer.

[0025] The heat insulating member may be a heat insulating block located on a surface of the first upper cover facing the heat insulating layer.

[0026] The battery module may include a battery cell stack in which a plurality of battery cells are stacked and a bus bar frame coupled to the front and rear surfaces of the battery cell stack in a longitudinal direction. The upper and lower surfaces of the battery cell stack may be open.

[0027] The battery pack may further include a thermally conductive resin layer between a lower surface of the battery module and the lower pack case.

[0028] Technical Effects

[0029] According to the present invention, high-temperature heat transferred to the upper portion of the battery pack can be effectively blocked. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a cross-sectional view of a battery pack in the prior art.

[0031] Figure 2 yes Figure 1 Magnified view of area A.

[0032] Figure 3is a perspective view of a battery module installed in the battery pack of the present invention.

[0033] Figure 4 It is a perspective view of the battery pack according to the first embodiment.

[0034] Figure 5 It is an exploded perspective view of the battery pack according to the first embodiment.

[0035] Figure 6 is along Figure 4 A cross-sectional view of the battery pack taken along line AA′.

[0036] Figure 7 is a schematic diagram illustrating a gas exhaust path according to the first embodiment.

[0037] Figure 8 It is a perspective view of a battery pack according to a second embodiment.

[0038] Fig. 9 is along Figure 8 A cross-sectional view of the battery pack taken along line BB′. DETAILED DESCRIPTION

[0039] Hereinafter, the present invention will be described in detail. Before describing the present invention, the terms or expressions used in this specification and claims should not be interpreted as limited to those commonly understood or defined in common dictionaries, but should be understood according to the meaning and concept matching the present invention on the basis that the inventor of the application can appropriately define the terms or expressions to best explain the principles of the present invention.

[0040] It should be understood that when the terms "include" and / or "comprise" are used herein, the presence of the mentioned features, wholes, steps, operations, elements, parts or combinations thereof is specified, but the presence or addition of one or more features, wholes, steps, operations, elements, parts or combinations thereof is not excluded. It should be understood that when a component (such as a layer, film, region, plate, etc.) is referred to as being "on" another component, the component is "directly" "on" the other component, or other components are placed between these components. It should be understood that when a component (such as a layer, film, region, plate, etc.) is referred to as being "below" another component, the component is "directly below" the other component, or other components are placed between these components. In addition, it should be understood that when a component is "on" another component, the component is "on" or "below" the other component.

[0041] The battery module is accommodated in the battery pack of the present invention.

[0042] The number of battery modules to be accommodated may be appropriately set according to the specifications required for the battery pack.

[0043] The battery module may be of the same type as that mounted on a conventional battery pack. That is, the battery module may include a module frame in which a plurality of battery cells connected in series or in parallel are housed.

[0044] Each battery cell constituting the battery module includes an electrode assembly, an electrolyte, and a shell. According to the configuration of the electrode assembly and the electrolyte, the plurality of battery cells may be classified as lithium-ion batteries, lithium-ion polymer batteries, lithium polymer batteries, and the like. According to the shape of the shell, each of the battery cells may be a cylindrical battery cell, a square battery cell, or a pouch-type battery cell. For example, the electrode assembly of a cylindrical battery cell is embedded in a cylindrical metal can. The electrode assembly of a square battery cell is embedded in a square metal can. The electrode assembly of a pouch-type battery cell is embedded in a pouch-shaped shell including an aluminum laminate. Hereinafter, for ease of illustration and description, the embodiments will be described with emphasis on pouch-type battery cells.

[0045] The electrode assembly contained in the battery case includes a positive electrode, a negative electrode, and a separator placed between the positive electrode and the negative electrode. According to the assembly form, the electrode assembly can be classified as a core-wound electrode assembly or a stacked electrode assembly. The core-wound electrode assembly is manufactured by winding the positive electrode, the negative electrode, and the separator placed between them. The stacked electrode assembly includes a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators placed between them stacked in sequence.

[0046] An exhaust hole is provided in an upper portion of the module frame to exhaust high temperature gas. Alternatively, a battery module in which a module frame structure is minimized for space utilization of a battery pack may be applied to a battery pack.

[0047] Figure 3 is a perspective view of a battery module 100 installed in the battery pack of the present invention.

[0048] like Figure 3 As shown, the battery module 100 includes a battery cell stack 110 in which a plurality of battery cells 111 are stacked, and a bus bar frame 120 located at the front and rear surfaces of the battery cell stack 110 to provide an electrical connection structure of the battery cells 111 .

[0049] The battery cell stack 110 may be manufactured by attaching a double-sided tape between the plurality of battery cells 111. Alternatively, although not shown, a tape may be further provided to surround a portion of the battery cell stack 110 to fix the plurality of battery cells 111.

[0050] The electrode lead 111a may protrude in a bidirectional or unidirectional manner from the battery cell 111. The battery cells 111 may be electrically connected by welding the electrode lead 111a to a bus bar or coupling the electrode lead 111a to electrode leads 111a of different polarities of adjacent battery cells 111.

[0051] like Figure 3 As shown, when the electrode leads 111 a protrude in a bidirectional manner, the bus bar frame 120 may be coupled to the front and rear surfaces of the battery cell stack 110 in the longitudinal direction.

[0052] A plurality of lead slits that allow the electrode leads 111a to pass therethrough may be provided in the bus bar frame 120. Figure 3 As shown, the electrode lead 111a passing through the lead slit can be bent toward the electrode lead 111a of different polarities to be welded together. Alternatively, according to the electrical connection design of the battery cell, the battery cell 111 can be electrically connected by providing an inner bus bar on the side of the bus bar frame 120 opposite to the surface of the bus bar frame 120 facing the battery stack 110 and welding the electrode lead 111a to the inner bus bar.

[0053] Terminal bus bars 121 are provided at opposite ends of the bus bar frame 120 for high voltage connection of the battery module 100. When the battery module 100 is mounted in a battery pack, the battery module 100 may be electrically connected by connecting a high voltage (HV) bus bar to the terminal bus bar 121.

[0054] The bus bar frame 120 may be manufactured by an injection molding method for insulation. However, the manufacturing method of the bus bar frame 120 is not particularly limited as long as an electrical connection structure of the battery cells 111 can be provided by appropriately molding an insulating material.

[0055] like Figure 3 As shown, the battery cell stack 110 of the battery module 100 may have an open upper surface and a lower surface. As described above, by minimizing the size of the module structure of the battery module 100 (including the module frame surrounding the upper surface, the lower surface, the left surface and the right surface of the battery stack 110, the end plate covering the front surface and the rear surface of the battery stack 110, etc.), the weight of the battery module 100 can be reduced. Therefore, when the battery module 100 is installed in the battery pack, the energy density of the battery pack can be improved.

[0056] Due to defects in the battery cells 111 and excessive charging and discharging, Figure 3 Excessive gas may also be generated in the battery module 100 shown. When the battery cell 111 bursts due to excessive high-temperature gas, the high-temperature gas is sprayed into the battery pack. Figure 3 When the battery module 100 is installed inside the battery pack, the heat-resistant member 13 may also expand or sag downward from the upper cover 12 toward the battery cell 111 due to the high-temperature gas. Figure 2 As shown. Figure 3In the case of the battery module 100 with a vent hole, since the module structure covering the battery cell 111 is minimized, the heat-resistant member 13 may be deformed, thereby applying an impact to the battery cell 111, thereby causing damage to the battery cell 111. Therefore, the present invention is applicable to Figure 3 The battery module 100 is applied to a battery pack.

[0057] Hereinafter, a battery pack of the present invention will be described in detail with reference to the accompanying drawings.

[0058] (First Embodiment)

[0059] Figure 4 It is a perspective view of the battery pack 1000 according to the first embodiment. Figure 5 It is an exploded perspective view of the battery pack 1000 according to the first embodiment. Figure 6 is along Figure 4 AA′ line of the battery pack 1000 is taken in cross section.

[0060] like Figures 4 to 6 As shown, the battery pack 1000 includes: a lower battery pack case 1100 having an accommodation space S in which a plurality of battery modules 100 are mounted; and an upper cover 1200 coupled to an upper portion of the lower battery pack case 1100 to cover the accommodation space S.

[0061] like Figure 4 and Figure 5 As shown, the lower battery pack housing 1100 includes: a bottom housing 1110 supporting the lower surface of the battery module 100 and a side wall housing 1120 installed along the periphery of the bottom housing 1110. Since the side wall housing 1120 is installed on the bottom housing 1110, an accommodation space S with an upper portion opened is formed. Thereafter, an upper cover 1200 is coupled to the upper portion of the lower battery pack housing 1100 to hermetically seal the accommodation space S.

[0062] The size of the accommodation space S may be determined by adjusting the area of ​​the bottom housing 1110 and the height of the sidewall housing 1120. The size of the accommodation space S may be appropriately designed by considering the number of battery modules 100 installed in the battery pack 1000, the internal structure of the lower battery pack housing 1100, etc., to achieve a desired output of the battery pack 1000.

[0063] The bottom case 1110 may be a plate having a rectangular shape. However, the rectangular shape is only an example, and the shape of the bottom case 1110 may be appropriately changed according to the design of the battery pack 1000. The bottom case 1110 may be formed of an appropriate material having a strength sufficient to withstand the overall load of the battery pack 1000.

[0064] The bottom shell 1110 can be manufactured by extrusion molding. Extrusion molding is a method of melting a raw material such as metal or plastic by heating, placing the molten raw material into a cylinder, and molding the molten raw material by extruding it from a mold using a screw or the like. The molded product manufactured by extrusion molding has a uniform cross-sectional shape along the extrusion direction. The bottom shell 1110 manufactured by extrusion molding includes a cooling channel (not shown) extending in the longitudinal direction of the bottom shell 1110. An external refrigerant supply system can be fluidly connected to the cooling channel to configure the cooling system of the battery pack 1000. In this case, since a cooling plate is not additionally required, the number of components of the battery pack 1000 can be reduced, and since there is no need for a process for fastening the cooling plate, the total number of processes can also be reduced.

[0065] The battery pack 1000 of the present embodiment may further include a thermally conductive resin layer 300 between the bottom housing 1110 of the lower battery pack housing 1100 and the battery module 100. Therefore, the battery module 100 may be more securely fixed to the bottom housing 1110. When the cooling system of the battery pack 1000 is configured by the bottom housing 1110 as described above, the thermally conductive resin layer 300 may be in full contact with the lower surface of the battery module 100 and the uneven surface of the bottom housing 1110 to maximize the cooled area of ​​the battery module 100. The thermally conductive resin layer 300 may be formed of a thermally conductive resin.

[0066] like Figure 5 As shown, the side wall housing 1120 extends in a direction perpendicular to the circumferential surface of the bottom housing 1110. The side wall housing 1120 can be coupled to the bottom housing 1110 using known techniques. For example, the side wall housing 1120 can be coupled to the bottom housing 1110 by friction stir welding or brazing.

[0067] The sidewall case 1120 may protect a structure installed in the battery pack 1000 from external impact. To this end, the sidewall case 1120 may be formed to a predetermined thickness.

[0068] The sidewall housing 1120 may provide a fastening structure to fix the battery pack 1000 when the battery pack 1000 is installed in a vehicle. Alternatively, when the battery pack 1000 is installed on an energy storage system (ESS), a coupling structure for mounting the battery pack 1000 may be provided.

[0069] Similarly, the side wall housings 1120 may be manufactured by extrusion molding. Therefore, each of the side wall housings 1120 may be provided with a hollow channel 1121 extending in the longitudinal direction of the side wall housing 1120. Therefore, the weight of the battery pack 1000 may be reduced by reducing the total weight of the side wall housings 1120.

[0070] like Figure 5 and Figure 6 As shown, the lower battery pack housing 1100 may further include a crossbeam 1130 that divides the accommodation space S into several parts and supports the side of the battery module 100 mounted on the bottom housing 1110. Therefore, the battery module 100 may be more firmly fixed and the overall structural rigidity of the battery pack 1000 may be improved. Electronic components or devices that manage the electrical state of the battery module 100 may be installed in the accommodation space S divided by the crossbeam 1130 as well as the battery module 100.

[0071] like Figure 5 and Figure 6 As shown, the cross beam 1130 may extend in the longitudinal direction and the height direction of the battery module 100. The length of the cross beam 1130 may be appropriately selected according to the design of the interior of the battery pack 1000.

[0072] The length (height) of the crossbeam 1130 in the height direction may be set to be greater than the height of the battery module 100. By setting the height of the crossbeam 1130 to be greater than the height of the battery module 100, the upper cover 1200 and the battery module 100 to be fastened to the upper surface of the crossbeam 1130 may be spaced apart from each other by a predetermined distance. As described above, the crossbeam 1130 may be coupled to the upper cover 1200 to support the upper cover 1200 at the bottom of the upper cover 1200.

[0073] The cross beam 1130 may also be manufactured by an extrusion molding method. In this case, a through channel 1132 extending in the longitudinal direction may be formed in the cross beam 1130. Therefore, the overall weight of the cross beam 1130 may be reduced.

[0074] like Figure 5 As shown, the lower battery pack housing 1100 may further include a center frame 1140 spanning the center area of ​​the bottom housing 1110. The center frame 1140 is installed at the center area of ​​the bottom housing 1110 while extending in the longitudinal direction of the bottom housing 1110. Therefore, the rigidity of the battery pack 1000 in the longitudinal direction can be further improved. In addition, by providing the center frame 1140 between the battery modules 100, an undesirable short circuit between the battery modules 100 can be prevented.

[0075] like Figures 4 to 6 As shown, the upper cover 1200 includes a first upper cover 1210 and a second upper cover 1220 .

[0076] like Figure 5 and Figure 6 As shown, the first upper cover 1210 is partially coupled to the second upper cover 1220 while facing the battery module 100 .

[0077] The first upper cover 1210 may be disposed under the second upper cover 1220 .

[0078] The thickness of the first upper cover 1210 and the second upper cover 1220 may be set to be different from each other. For example, the thickness of the first upper cover 1210 may be greater than the thickness of the second upper cover 1220. In this case, even when the second upper cover 1220 is damaged due to a strong external impact applied thereto, the first upper cover 1210 can protect the battery module 100 from external impact. Alternatively, the thickness of the second upper cover 1220 may be greater than the thickness of the first upper cover 1210. In this case, even when a strong external force is applied to the upper cover 1200, due to the rigidity of the second upper cover 1220, the battery module 100 or the battery pack 1000 can be protected from the external force.

[0079] The first upper cover 1210 may be manufactured as a flat plate having a shape corresponding to the circumferential shape of the bottom housing 1110. For example, when the bottom housing 1110 has a rectangular shape, the first upper cover 1210 may be manufactured as a rectangular flat plate. The shape of the first upper cover 1210 is not particularly limited as long as the first upper cover 1210 covers the accommodation space S to hermetically seal the interior of the battery pack 1000.

[0080] The first upper cover 1210 is fastened to the upper surfaces of the side wall housing 1120 and the crossbeam 1130. In this case, the height of the crossbeam 1130 is greater than the height of the battery module 100, so the first upper cover 1210 is disposed to be spaced apart from the battery module 100, such as Figure 6 shown.

[0081] In the battery pack 10 of the related art, the heat-resistant member 13 is mounted on the inner side of the upper cover 12 facing the battery module 1, so when the high-temperature gas is ejected, the exhaust hole 1a of the battery module 1 may be blocked by the heat-resistant member 13. Figure 6 As shown, the lower surface 1211 of the first upper cover 1210 faces the upper surface 130 of the battery module 100. That is, no member that blocks the exhaust holes in the battery module 100 even when high-temperature gas is discharged from the battery module 100 is installed on the surface of the first upper cover 1210 facing the battery module 100. Therefore, dangers that may occur due to the blockage of the exhaust holes (for example, heat transfer to adjacent battery cells, explosion of the battery module 100, etc.) can be prevented. Figure 3 When the battery module 100 is constructed, no separate heat-resistant member is provided on the lower surface 1211 of the first upper cover 1210, thereby preventing the battery cells 111 from being damaged due to deformation of the heat-resistant member.

[0082] Due to the first upper cover 1210 , the battery modules 100 are isolated in the sealed space between the beams 1130 . Therefore, even when high-temperature gas is ejected in a predetermined battery module 100 , the high-temperature gas is not transmitted to the battery modules 100 outside the beams 1130 .

[0083] like Figures 4 to 6 As shown, at least a portion of the second upper cover 1220 is spaced apart from the first upper cover 1210, so that a heat insulation layer I is provided between the first upper cover 1210 and the second upper cover 1220. For example, the edge portions of the first upper cover 1210 and the second upper cover 1220 may be coupled to each other, and at least a portion of their central portions may be spaced apart from each other. In this case, the space between the first upper cover 1210 and the second upper cover 1220 may be the heat insulation layer I.

[0084] The heat insulating layer I may be an air layer between the first upper cover 1210 and the second upper cover 1220. Alternatively, the heat insulating layer I may be a vacuum space having a predetermined vacuum degree. As described above, the heat insulating layer I is disposed inside the upper cover 1200, so that even when a separate heat-resistant member is not applied to the lower surface 1211 of the first upper cover 1210, the transfer of heat toward the upper portion of the battery pack 1000 can be minimized. In addition, when the battery pack 1000 is mounted on the bottom of the vehicle, the transfer of high-temperature heat to passengers in the vehicle can be minimized.

[0085] like Figure 5 and Figure 6 As shown, the insulation member 200 may be installed in the insulation layer I to further minimize the transfer of heat toward the upper portion of the battery pack 1000.

[0086] like Figure 5 and Figure 6 As shown, the heat insulating member 200 is provided on the surface of the first upper cover 1210 facing the heat insulating layer 1. That is, the heat insulating member 200 is installed in the upper cover 1200. Therefore, even when high temperature gas is ejected from the battery cell 111 to the battery module 100, the first upper cover 1210 blocks the gap between the heat insulating member 200 and the battery module 100, thereby minimizing thermal deformation of the heat insulating member 200.

[0087] like Figure 5 As shown, the heat insulating member 200 may be a heat insulating block or a heat insulating sheet having a rectangular shape. Alternatively, the heat insulating member 200 may be a heat resistant resin applied to the surface of the first upper cover 1210 facing the heat insulating layer I.

[0088] The thermal insulation member 200 may include at least one selected from the group consisting of nitrile rubber, natural rubber, fluororubber, high cis BR (HBR), styrene butadiene rubber, chloroprene rubber, ethylene propylene diene monomer (EPDM), and silicone rubber. However, according to the present invention, the thermal insulation member 200 is disposed in the thermal insulation layer I between the first upper cover 1210 and the second upper cover 1220, so the battery module 100 is less likely to be damaged due to thermal deformation of the thermal insulation member 200. Therefore, the material of the thermal insulation member 200 is not particularly limited as long as the thermal conductivity of the material is low and thus heat transfer can be delayed.

[0089] The heat insulation member 200 may be a single member having an area corresponding to the area of ​​the first upper cover 1210. Alternatively, as Figure 5 and Figure 6 As shown, the insulation member 200 may include a plurality of members spaced apart from each other by a predetermined distance in the longitudinal direction of the battery pack 1000 to correspond to the upper portion of the battery module 100. The number and area of ​​the insulation members 200 to be installed are not particularly limited as long as they are installed in the first upper cover 1210 and block the heat generated from the battery module 100.

[0090] like Figures 4 to 6 As shown, the second upper cover 1220 may include an upper plate 1221 spaced apart from the first upper cover 1210 to define the heat insulation layer I, and a partition 1222 bent from the upper plate 1221 toward the first upper cover 1210.

[0091] The partition plate 1222 is connected to the end of the upper plate 1221 in the width direction and is bent toward the first upper cover 1210. In this case, refer to Figures 4 to 6 , the width direction of the upper plate 1221 corresponds to the longitudinal direction of the battery pack 1000, and the longitudinal direction of the upper plate 1221 corresponds to the width direction of the battery pack 1000. Figure 5 and Figure 6 As shown, the extended end of the partition 1222 is provided with a flat surface substantially parallel to the first upper cover 1210. Since the flat surface of the partition 1222 is in contact with the first upper cover 1210, the heat insulation layer I is divided into several parts.

[0092] like Figure 5 and Figure 6 As shown, the partition 1222 can support the upper plate 1221 so that the upper plate 1221 is spaced apart from the first upper cover 1210. Therefore, even when an external shock is applied to the upper plate 1221, the partition 1222 connected to the upper plate 1221 can disperse the external shock or vibration caused by the external shock. In addition, the overall durability and structural rigidity of the second upper cover 1220 can be improved.

[0093] Since the thermal insulation layer I is divided into several parts by the partitions 1222, even if a part of the thermal insulation layer I is overheated, the heat can be blocked from being transferred to the adjacent parts of the thermal insulation layer I by the partitions 1222. That is, even when a module under a part of the thermal insulation layer I has a thermal runaway and the part of the thermal insulation layer I is overheated, the heat can be blocked from being transferred from the part of the thermal insulation layer I to other adjacent parts of the thermal insulation layer I by the partitions 1222. Therefore, the partitions 1222 can also prevent the heat from being propagated to the adjacent modules.

[0094] The partition plate 1222 may be fixed to the crossbeam 1130 together with the first upper cover 1210. Figure 5 and Figure 6 As shown, a plurality of fasteners B may pass through the second through hole H2 in the partition 122 and the first through hole H1 in the first upper cover 1210 and be coupled to the fastening groove 1131 in the crossbar 1130 to fasten the partition 1222 and the first upper cover 1210 to the crossbar 1130. In this case, a sealing member (not shown) such as an O-ring may be interposed between the fastener B and the first through hole H1 and the second through hole H2 to maintain airtightness or watertightness of the battery pack 1000. The fastener B may be a bolt.

[0095] However, the present invention is not limited thereto, and the coupling member is not particularly limited as long as the partition plate 1222 and the first upper cover 1210 can be fixed to the crossbeam 1130. For example, the partition plate 1222 and the first upper cover 1210 may be coupled to each other by welding, and the partition plate 1222 and the first upper cover 1210 coupled to each other may be welded or fastened to the crossbeam 1130.

[0096] The battery pack 1000 according to the present embodiment includes the upper cover 1200 having the heat insulating layer I, and therefore, unlike the prior art, there is no need to install a separate heat-resistant member in the accommodation space S of the battery module 100. Therefore, it is possible to prevent the battery module 100 or the battery cell 111 from being damaged or exploded due to deformation of the heat-resistant member. In addition, by installing the heat insulating member 200 in the heat insulating layer I, it is possible to prevent heat from being transferred to the upper portion of the battery pack 1000.

[0097] However, when gas is continuously ejected from the battery module 100, the pressure of the accommodation space S may excessively increase, thereby causing the battery pack 1000 to explode. Therefore, when the gas ejected from the battery module 100 accumulates in the accommodation space S to a certain extent, a device for discharging the gas to the outside of the battery pack 1000 is required.

[0098] Figure 7 is a schematic diagram illustrating a gas exhaust path P according to the present embodiment.

[0099] like Figure 7 As shown, the surface of the side wall housing 1120 facing the accommodation space S may be provided with a side wall communication hole 1122 for communication between the accommodation space S and the hollow channel 1121. In addition, the side wall housing 1120 is installed along the periphery of the bottom housing 1110 so that the hollow channels 1121 in the side wall housing 1120 can be connected to each other. Therefore, when the high temperature gas is ejected from the battery module 100 to the accommodation space S, the high temperature gas can flow to the hollow channel 1121 of the side wall housing 1120 facing the battery module 100 through the side wall communication hole 1122, and then flow to the hollow channel 1121 of the other side wall housing 1120.

[0100] like Figure 7As shown, each of the side wall housings 1120 may include a gas discharge hole (not shown) for communication between the hollow passage 1121 and the outside, and an exhaust device 1122a installed in the gas discharge hole.

[0101] In the exhaust device 1122a, an exhaust cap for preventing gas leakage may be provided in the gas discharge hole. In addition, a gas sealing member may be installed in the gas discharge hole or the exhaust cap. The gas sealing member may be, for example, a sheet-type member, and may be deformed above a predetermined pressure and / or a predetermined temperature to open a gas outlet to the outside. For example, a gas sealing member may be a rupture piece, which is configured to rupture when the pressure of the gas to be discharged (vented) is greater than or equal to a predetermined pressure. Alternatively, the sheet-type member may melt above a predetermined temperature and open a gas outlet. To this end, the sheet-type member may be formed by a film or foam material susceptible to high temperature. Therefore, when high-temperature gas accumulates in the hollow passage 1121 and the pressure and / or temperature of the hollow passage 1121 rises to above a certain level, the gas sealing member opens the gas discharge hole to discharge high-temperature gas to the outside.

[0102] For ease of illustration, Figure 7 The gas discharge path P shown is merely an example of various gas discharge paths. The gas discharge path is not particularly limited as long as the gas in the housing space S can be discharged to the outside.

[0103] (Second Embodiment)

[0104] Figure 8 It is a perspective view of a battery pack 2000 according to the second embodiment. Fig. 9 is along Figure 8 BB′ line of the battery pack 2000 .

[0105] Even when the high-temperature gas discharged into the accommodation space S is discharged to the outside of the battery pack 2000 through the sidewall housing 1120, the high-temperature gas may transfer heat to the first upper cover 2210 and the second upper cover 2220 during the high-temperature gas discharge. As the upper cover 2200 is heated, the air layer of the heat insulating layer I in the upper cover 2200 may also be heated. In this case, for example, since the air expands due to a sharp increase in temperature, the upper cover 2200 may be separated from the first upper cover 2210, thereby causing damage to the upper cover 2200.

[0106] The battery pack 2000 of the present embodiment is different from the battery pack 1000 of the first embodiment in that the second upper cover 2200 is provided with a plurality of upper discharge holes 2223 for communication between the heat insulation layer 1 and the outside of the battery pack 2000.

[0107] The battery pack 2000 of the present embodiment can discharge heated air from the heat insulating layer 1 through the upper discharge hole 2223, thereby preventing the upper cover 2200 from being damaged due to the expansion of the air in the heat insulating layer 1. In addition, the heated air in the heat insulating layer 1 can be discharged to the outside through the upper discharge hole 2223, and relatively cold air can be supplied to the heat insulating layer 1 to circulate the air in the heat insulating layer 1. As described above, even when the air in the heat insulating layer 1 is heated, the air can be circulated through the upper discharge hole 2223 to cool the air in the heat insulating layer 1. Even if the upper discharge hole 2223 is provided, the accommodation space S is closed by the first upper cover 2210, so the air tightness or water tightness inside the battery pack 2000 is not significantly reduced.

[0108] The upper discharge hole 2223 extends from the outer surface of the second upper cover 2220 to the inner surface of the second upper cover 2200 facing the insulation layer 1, for communicating the insulation layer 1 with the outside. When viewed from the top of the battery pack 2000, the upper discharge hole 2223 may have a circular shape, an elliptical shape, a quadrilateral shape, a cross shape, or a combination thereof.

[0109] like Figure 8 and Fig. 9 As shown, the upper discharge hole 2223 may be provided in the upper plate 2221 .

[0110] However, when the upper discharge hole 2223 is always open, unexpected fluid may penetrate into the battery pack 2000 through various paths. In addition, foreign matter that penetrates through the upper discharge hole 2223 may cause damage (corrosion, contamination, etc.) to the first upper cover 2210. In this case, the air tightness and water tightness of the battery pack 2000 cannot be maintained, resulting in unexpected failures when the battery pack 2000 is used. In order to prevent this problem, an upper discharge member 2223a may be installed in the upper discharge hole 2223.

[0111] The upper discharge member 2223a may close the upper discharge hole 2223 to hermetically close the thermal insulation layer I. However, when the internal temperature of the thermal insulation layer I rises to above a predetermined temperature because the air in the thermal insulation layer I is heated by the high-temperature gas discharged from the battery module 100, the upper discharge member 2223a may be broken or damaged, causing the thermal insulation layer I to communicate with the outside of the battery pack 2000. When the upper discharge hole 2223 is open, the heated air may be discharged from the thermal insulation layer I and the outside air may be introduced to cool the thermal insulation layer I.

[0112] The upper exhaust member 2223a may be configured similarly to the exhaust device 1122a of the above-described first embodiment. For example, a sheet-type gas sealing member may be installed in each upper exhaust hole 2223.

[0113] As described above, the upper cover 2200 of the present embodiment may not discharge heated air directly from the heat insulating layer 1, but may selectively discharge heated air only under conditions above a predetermined temperature. Considering the safety of passengers riding in the vehicle, the predetermined temperature condition may be selected from an appropriate range.

[0114] The conditions that cause the upper discharge member 2223a to rupture or be damaged may be different from the conditions that allow the exhaust device 1122a to open the gas discharge hole. For example, the upper discharge member 2223a may rupture at a temperature lower than the temperature at which the exhaust device 1122a opens the gas discharge hole, thereby opening the upper discharge hole 2223.

[0115] According to the present embodiment, when the temperature of the heat insulation layer 1 excessively rises, heated air may be discharged from the heat insulation layer 1 to prevent deformation and damage of the second upper cover 2220 or the upper cover 2200 due to air expansion and to cool the heat insulation layer 1. In addition, by installing an upper discharge member 2223a in the upper discharge hole 2223, heated air may be selectively discharged only in a specific case where the temperature of the heat insulation layer 1 rises above a predetermined temperature.

[0116] The same configuration as that of the first embodiment can also be applied to this embodiment. Fig. 9 As shown, the bottom surface 2211 of the first upper cover 2210 and the upper surface 130 of the battery module 100 may directly face each other, and the second upper cover 2220 may include an upper plate 2221 and a separator 2222 .

[0117] The above description is intended only to provide examples of the technical concept of the present invention. Therefore, without departing from the essential features of the present invention, a person of ordinary skill in the technical field to which the present invention belongs may make various modifications and changes. Therefore, the drawings of the present invention set forth herein are not intended to limit the technical concept of the present invention, but to describe the technical concept. Moreover, the scope of the technical concept of the present invention is not limited by these drawings. The scope of protection of the present invention should be interpreted based on the attached claims, and all technical concepts within the same scope as the present invention should be interpreted as being included within the scope of the present invention.

[0118] In this specification, terms indicating directions such as up, down, left, right, front, and back are used merely for the purpose of convenience of description, and it is apparent that the terms may change depending on the position of an object or an observer.

[0119] (List of Reference Signs)

[0120] 1: Battery module of the prior art

[0121] 10: Prior art battery pack

[0122] 11: Lower battery pack housing of a battery pack in the prior art

[0123] 12: Upper cover of battery pack in prior art

[0124] 13: Heat-resistant components

[0125] 100: Battery module

[0126] 1000, 2000: Battery pack

[0127] 1100: Lower battery pack housing

[0128] 1110: Bottom shell

[0129] 1120: Sidewall housing

[0130] 1130: Beam

[0131] 1140: Center frame

[0132] 1200, 2200: Upper cover

[0133] 1210, 2210: First cover

[0134] 1220, 2220: Second upper cover

[0135] I: Insulation layer

Claims

1. A battery pack, comprising: Battery modules; a lower battery pack housing having a receiving space in which the battery module is installed; as well as an upper cover coupled to an upper portion of the lower battery pack housing to cover the accommodation space, Wherein, the upper cover comprises: a first upper cover, the first upper cover facing the battery module; and A second upper cover, at least a portion of which is spaced apart from the first upper cover to form a heat insulation layer between the first upper cover and the second upper cover.

2. The battery pack according to claim 1, wherein: The first upper cover and the battery module are spaced apart from each other, and A lower surface of the first upper cover faces an upper surface of the battery module.

3. The battery pack according to claim 1, wherein: The second upper cover is provided with a plurality of upper discharge holes for communication between the heat insulating layer and the outside.

4. The battery pack according to claim 3, wherein: The second upper cover includes an upper discharge member configured to close the upper discharge hole to hermetically seal the heat insulating layer, and to rupture for communication between the heat insulating layer and the outside when an inner temperature of the heat insulating layer increases by a predetermined temperature.

5. The battery pack according to claim 1, wherein: The second upper cover includes: an upper plate spaced apart from the first upper cover; and a partition plate connected to ends of the upper plate in a width direction and bent from the upper plate toward the first upper cover to divide the heat insulating layer into several parts.

6. The battery pack according to claim 1, wherein: The lower battery pack housing includes: a bottom housing configured to support a bottom surface of the battery module; and a crossbeam configured to divide the accommodation space into several parts and support a side surface of the battery module, Wherein, the crossbeam is connected to the upper cover.

7. The battery pack according to claim 1, wherein: The thickness of the first upper cover is different from the thickness of the second upper cover.

8. The battery pack according to claim 1, wherein: The lower battery pack housing includes a bottom housing configured to support a lower surface of the battery module and a side wall housing installed along a periphery of the bottom housing, Wherein, each of the side wall shells comprises: an inner hollow passage; and A side wall communication hole for communication between the accommodation space and the inner hollow passage, the side wall communication hole being provided in a surface of the side wall housing facing the accommodation space. 9 . The battery pack according to claim 1 , further comprising a heat insulating member located on the heat insulating layer.

10. The battery pack according to claim 9, wherein: The heat insulating member includes a heat insulating block located on a surface of the first upper cover facing the heat insulating layer.

11. The battery pack according to claim 1, wherein: The battery module comprises: a battery cell stack in which a plurality of battery cells are stacked; and a bus bar frame coupled to the front and rear surfaces of the battery cell stack in the longitudinal direction, Wherein, the upper surface and the lower surface of the battery cell stack are open. 12 . The battery pack according to claim 1 , further comprising a thermally conductive resin layer between a lower surface of the battery module and the lower pack case.

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