Battery Pack

Abstract

The present invention relates to a battery pack. The battery pack according to the present invention includes a battery module, a lower pack housing having an accommodation space in which the battery module is installed, and an upper cover coupled to the upper portion of the lower pack housing so as to cover the accommodation space. The upper cover includes a first upper cover facing the battery module, and a second upper cover at least partially separated from the first upper cover so as to have a heat insulating layer therebetween.

Description

Technical Field

[0001] The present invention relates to a battery pack provided with an upper cover including a heat insulating layer.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0028170 filed on March 3, 2023, and all contents disclosed in the literature of the Korean patent application are included as part of this specification.

Background Art

[0003] In recent years, rechargeable secondary batteries have been widely used as an energy source for wireless mobile devices. In addition, secondary batteries have also attracted attention as an energy source for electric vehicles, hybrid electric vehicles, etc., which are proposed as a solution to solve air pollution caused by existing gasoline vehicles, diesel vehicles, etc. that use fossil fuels.

[0004] In the case of secondary batteries used in small devices, 2 - 3 battery cells are arranged. In the case of secondary batteries used in medium and large devices such as automobiles, a battery module in which a large number of battery cells are electrically connected is used. In addition, a battery pack in which a plurality of battery modules are electrically connected can be used.

[0005] A battery cell includes an electrode assembly in which a positive electrode, a negative electrode, and a separator are laminated, and an electrolytic solution is housed in a case. Depending on the shape of such a case, the battery cell can be classified into a cylindrical type, a prismatic type, and a pouch type battery cell.

[0006] A battery cell can be repeatedly charged and discharged by an electrochemical reaction between its components. However, if the charging and discharging are repeated excessively, or if there is a defect in the battery cell itself, the temperature of the battery cell may rise abnormally. If the temperature of such a battery cell cannot be properly adjusted, the battery cell may explode and generate high-temperature gas. Or, it may raise the temperature of adjacent battery cells and cause continuous explosions. To prevent this, a battery module containing a plurality of battery cells may be provided with a venting hole at the top of the module. When the temperature inside the battery module rises excessively, the high-temperature gas can be discharged to the top through the venting hole of the battery module.

[0007] FIG. 1 is a cross-sectional view showing a cross-section of a conventional battery pack 10, and FIG. 2 is an enlarged view of region A in FIG. 1.

[0008] As shown in FIG. 1, the battery pack 10 includes a lower pack housing 11 that houses the battery module 1, and an upper cover 12 that covers the lower pack housing 11.

[0009] The battery pack 10 can be installed at the lower part of a vehicle. As described above, when high-temperature gas F is discharged to the top of the battery module 1, the high-temperature heat can be transmitted to the passengers in the vehicle. To prevent this, as shown in FIGS. 1 and 2, in the conventional battery pack 10, a refractory member 13 is attached to the inner surface of the upper cover 12. The refractory member 13 can be a heat-resistant block or a heat-resistant sheet made of a heat-resistant material. Or, it can be a heat-resistant layer in which a heat-resistant resin is applied to the inner surface of the upper cover 12. However, as shown in FIG. 2, there is a problem that the venting hole 1a of the battery module 1 is closed due to the refractory member 13 expanding or melting due to the high-temperature gas and falling onto the battery module 1 disposed below it. In this case, the high-temperature gas cannot be discharged from the inside of the battery module 1, and due to the rapid heat transfer between adjacent battery cells, the battery cell or the battery module 1 may explode.

[0010] Therefore, it is necessary to develop a technology that can prevent the problem that the venting hole 1a is closed by the refractory member 13 described above.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0012] The present invention has been devised to solve the above problems, and provides a battery pack including an upper cover that can effectively block high-temperature heat transmitted in the upward direction of the battery pack without closing the venting hole of the battery module even in a thermal runaway situation.

Means for Solving the Problems

[0013] The battery pack of the present invention for solving the above problems includes a battery module, a lower pack housing having an accommodation space in which the battery module is installed, and an upper cover coupled to the upper part of the lower pack housing so as to cover the accommodation space. The upper cover includes a first upper cover facing the battery module, and a second upper cover at least partially separated from the first upper cover so as to have a heat insulating layer therebetween.

[0014] The first upper cover and the battery module are arranged to be separated from each other, and the lower surface of the first upper cover can directly face the upper surface of the battery module.

[0015] The second upper cover may be provided with a plurality of upper discharge holes so that the heat insulating layer can communicate with the outside.

[0016] The second upper cover may include an upper discharge member that closes the upper discharge hole to hermetically seal the heat insulation layer and ruptures when the temperature inside the heat insulation layer rises above a predetermined temperature to communicate the heat insulation layer with the outside.

[0017] The second upper cover may include an upper plate spaced apart from the first upper cover and partition plates connected to widthwise end portions of the upper plate and bent from the upper plate toward the first upper cover so as to partition the heat insulation layer into a plurality of sections.

[0018] The lower pack housing includes a bottom housing that supports the lower surface of the battery module and cross beams that partition the accommodation space into a plurality of sections and support the side surfaces of the battery module, and the cross beams may be coupled to the upper cover.

[0019] The thickness of the first upper cover may be different from the thickness of the second upper cover.

[0020] The lower pack housing includes a bottom housing that supports the lower surface of the battery module and a side wall housing installed along the edge of the bottom housing, and the side wall housing has a hollow channel inside and may be provided with a side wall communication hole that communicates the accommodation space with the hollow channel on a surface facing the accommodation space.

[0021] It may include a heat insulation member installed in the heat insulation layer.

[0022] The heat insulation member may be a heat insulation block disposed on a surface of the first upper cover facing the heat insulation layer.

[0023] The battery module includes a battery cell stack in which a plurality of battery cells are stacked and a bus bar frame coupled to the battery cell stack on the longitudinal front and rear surfaces of the battery cell stack, and the battery cell stack may have an open upper surface and a lower surface.

[0024] It may further include a thermally conductive resin layer interposed between the lower surface of the battery cell laminate and the lower pack housing.

Advantages of the Invention

[0025] According to the present invention, high-temperature heat transmitted to the upper part of the battery pack can be efficiently blocked.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0027] Hereinafter, the present invention will be described in detail. Before that, terms and words used in this specification and the claims should not be construed as being limited to their ordinary or dictionary meanings, but should be construed as meanings and concepts consistent with the technical idea of the present invention based on the principle that the inventor can appropriately define the concept of the terms in order to explain his own invention in the best way.

[0028] In this application, terms such as "comprising" and "having" are intended to specify the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and should be understood not to preclude in advance the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Also, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only the case where it is directly on the other part but also the case where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only the case where it is directly under the other part but also the case where there is another part in between. Further, in this application, being "disposed on" can include not only the upper part but also the case of being disposed on the lower part.

[0029] The battery pack of the present invention houses a battery module.

[0030] The number of battery modules to be housed can be suitably set according to the required specifications of the battery pack.

[0031] The battery module can be of the same type as the battery module implemented in a conventional battery pack. That is, the battery module can include a module frame housing a plurality of battery cells connected in series or in parallel.

[0032] Each battery cell constituting the battery module includes an electrode assembly, an electrolyte, and a case. A plurality of battery cells can be classified into lithium-ion batteries, lithium-ion polymer batteries, lithium polymer batteries, etc. according to the configuration of the electrode assembly and the electrolyte. Further, the battery cell can be any one of a cylindrical battery cell, a prismatic battery cell, and a pouch-type battery cell according to the shape of the case. For example, the electrode assembly of the cylindrical battery cell is built into a cylindrical metal can. The electrode assembly of the prismatic battery cell is built into a prismatic metal can. The electrode assembly of the pouch-type battery cell is built into a pouch case including an aluminum laminate sheet. Hereinafter, for the convenience of illustration and description, the pouch-type battery cell will be mainly described.

[0033] The electrode assembly built into the battery case includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The electrode assembly is classified into a jelly roll type and a stack type according to the assembled form. The jelly roll type is obtained by winding a positive electrode, a negative electrode, and a separator interposed therebetween. The stack type includes a plurality of positive electrodes stacked in sequence, a plurality of negative electrodes, and a plurality of separators interposed therebetween.

[0034] On the upper part of the module frame, a venting hole for discharging high-temperature gas is provided. Alternatively, a battery module with a minimized module frame structure can be applied to the battery pack for efficient use of the space in the battery pack.

[0035] FIG. 3 is a perspective view of the battery module 100 installed in the battery pack of the present invention.

[0036] As shown in FIG. 3, 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 that provides an electrical connection structure for the battery cells on the front and rear surfaces of the battery cell stack 110.

[0037] The battery cell stack 110 can be manufactured by attaching double-sided tape between a plurality of battery cells 111. Alternatively, although not shown, a band for fixing a plurality of battery cells 111 while surrounding a part of the battery cell stack 110 may be further provided.

[0038] Depending on its design, the electrode lead 111a of the battery cell 111 can protrude from the battery cell in both directions or in a single direction. A plurality of battery cells can be electrically connected by welding the electrode lead 111a to the bus bar or by coupling it with the electrode lead 111a having the other polarity of the adjacent battery cell 111.

[0039] As shown in FIG. 3, when the electrode lead 111a protrudes in both directions, the bus bar frame 120 can be coupled to the battery cell stack 110 at the front and rear surfaces in the longitudinal direction of the battery cell stack 110.

[0040] The bus bar frame 120 may be provided with a plurality of lead slits through which the electrode lead 111a can pass. As shown in FIG. 3, the electrode lead 111a passing through the lead slit can be bent toward the electrode lead 111a having a different polarity from each other and the electrode leads 111a can be welded together. Alternatively, depending on the electrical connection design of the battery cells, an inter-bus bar is provided on the surface opposite to the surface of the bus bar frame 120 facing the battery cell stack 110, and a plurality of battery cells 111 can be electrically connected by welding the electrode lead 111a to the inter-bus bar.

[0041] Terminal bus bars 121 for high-voltage connection of the battery module 100 are provided at both side ends of the bus bar frame 120. When the battery module 100 is installed in a battery pack, an HV (High Voltage) bus bar is connected to the terminal bus bar 121, and a plurality of battery modules 100 can be electrically connected.

[0042] The bus bar frame 120 can be manufactured by a plastic injection molding process for insulation. However, the manufacturing method of the bus bar frame 120 is not particularly limited as long as the insulating material can be suitably molded to provide the electrical connection structure of the battery cell 111.

[0043] As shown in FIG. 3, the battery cell stack 110 of the battery module 100 may have an open upper surface and a lower surface. Thus, by minimizing the application of the module structure of the battery module 100 (for example, the module frame surrounding the upper, lower, left, and right surfaces of the battery cell stack 110, the end plate covering the front and rear surfaces of the battery cell stack 110, etc.), the weight of the battery module 100 can be reduced. Therefore, when such a battery module 100 is installed in a battery pack, the energy density of the battery pack can be improved.

[0044] In the battery module 100 shown in FIG. 3, excessive gas may also be generated inside the battery cell 111 due to a defect in the battery cell 111 itself or excessive charge and discharge. If the battery cell 111 explodes due to this excessive gas, the high-temperature gas will eject into the battery pack. Therefore, even when the battery module 100 shown in FIG. 3 is installed inside the battery pack, due to the high-temperature gas, the fireproof member 13 may expand as shown in FIG. 2, or the fireproof member 13 may fall from the upper cover 12 to the battery cell 111. In the case of the battery module 100 shown in FIG. 3, since the module structure covering the battery cell 111 is minimized, the deformed fireproof member 13 may impact the battery cell 111 and damage the battery cell 111. Therefore, even when the battery module 100 shown in FIG. 3 without a venting hole is applied to the battery pack, it is necessary to solve the problems of the present invention.

[0045] Hereinafter, the battery pack of the present invention will be specifically described with reference to the drawings.

[0046] (First Embodiment) FIG. 4 is a perspective view of the battery pack 1000 according to the first embodiment of the present invention, FIG. 5 is an exploded perspective view of the battery pack 1000 according to the first embodiment of the present invention, and FIG. 6 is a cross-sectional view of the battery pack 1000 taken along the line A-A' of FIG. 4.

[0047] As shown in FIGS. 4 to 6, the battery pack 1000 includes a lower pack housing 1100 having an accommodation space S in which a plurality of battery modules 100 are installed, and an upper cover 1200 coupled to the upper portion of the lower pack housing 1100 so as to cover the accommodation space S.

[0048] As shown in FIGS. 4 and 5, the lower pack housing 1100 includes a bottom housing 1110 that supports the lower surface of the battery module 100, and a side wall housing 1120 installed along the edge of the bottom housing 1110. By installing the side wall housing 1120 on the bottom housing 1110, an accommodation space S with an open upper portion is formed. Then, the upper cover 1200 is coupled to the upper portion of the lower pack housing 1100 to airtight seal the accommodation space S.

[0049] The size of the accommodation space S can be determined by adjusting the area of the bottom housing 1110 and the height of the side wall housing 1120. Such a size of the accommodation space S can be suitably designed in consideration of the number of battery modules 100 installed inside the battery pack 1000, the internal structure of the lower pack housing 1100, etc. to achieve the output required for the battery pack 1000.

[0050] The bottom housing 1110 can be a plate having a rectangular shape. However, this is just an example, and the shape of the bottom housing 1110 can be suitably changed according to the design of the battery pack 1000. Also, the bottom housing 1110 can be manufactured from a suitable material so as to have a strength capable of withstanding the overall load of the battery pack 1000.

[0051] The bottom housing 1110 can be manufactured by an extrusion process. The extrusion process is a method in which a raw material such as metal or plastic is heated and melted, then put into a cylinder and extruded from a die using a screw or the like to form a shape. The molded product manufactured by the extrusion process has a uniform cross-sectional shape along the extrusion direction. The bottom housing 1110 manufactured by such an extrusion process has a cooling channel (not shown) extending in the longitudinal direction of the bottom housing 1110 inside. An external refrigerant supply system can be fluidly connected to such a cooling channel to constitute a cooling system of the battery pack 1000. In this case, since a separate cooling plate may not be provided, the number of parts of the battery pack 1000 can be reduced, and since there is no need to perform a separate process for fastening the cooling plate, the total number of processes can be reduced.

[0052] The battery pack 1000 of the present embodiment may further include a thermally conductive resin layer 300 interposed between the bottom housing 1110 of the lower pack housing 1100 and the battery module. Thereby, the battery module 100 can be more firmly fixed to the bottom housing 1110. Further, when the cooling system of the battery pack 1000 is configured through the bottom housing 1110 as described above, the thermally conductive resin layer 300 can sufficiently contact the lower surface of the battery module 100 and the non-uniform surface of the bottom housing 1110, so that the cooling area of the battery module 100 can be maximized. Such a thermally conductive resin layer 300 can be composed of a thermal resin.

[0053] As shown in FIG. 5, the side wall housing 1120 extends in a direction perpendicular to the edge surface of the bottom housing 1110. The side wall housing 1120 can be coupled to the bottom housing 1110 using a known technique. For example, the side wall housing 1120 can be coupled to the bottom housing 1110 by friction stir welding or brazing.

[0054] The side wall housing 1120 can protect the structures installed inside the battery pack 1000 from external impacts. For this purpose, the side wall housing 1120 can be manufactured to have a predetermined thickness.

[0055] The side wall housing 1120 can provide a fastening structure by which the battery pack 1000 can be fixed when the battery pack 1000 is installed on the vehicle body. Or, when the battery pack 1000 is mounted on an ESS (Energy Storage System), it can provide a coupling structure by which the battery pack 1000 can be installed.

[0056] The side wall housing 1120 can also be manufactured by an extrusion molding method. Accordingly, the side wall housing 1120 can include a hollow channel 1121 extending in the longitudinal direction of the side wall housing 1120 inside. Thereby, the weight of the battery pack 1000 can be reduced by reducing the overall weight of the side wall housing 1120.

[0057] As shown in FIGS. 5 and 6, the lower pack housing 1100 can further include a cross beam 1130 that divides the accommodation space S into a plurality of compartments and supports the side surfaces of the battery modules 100 installed on the bottom housing 1110. Thereby, the battery modules 100 can be fixed more firmly, and the overall structural rigidity of the battery pack 1000 can be improved. In the accommodation space S partitioned by the cross beam 1130, not only the battery modules 100 but also electrical components or devices for managing the electrical state of the battery modules 100 can be installed.

[0058] As shown in FIGS. 5 and 6, the cross beam 1130 can extend in the longitudinal direction and the height direction of the battery module 100. The length of the cross beam 1130 can be suitably selected according to the internal design of the battery pack 1000.

[0059] The length (height) of the cross beam 1130 in the height direction can be set higher than the height of the battery module 100. By setting the height of the cross beam 1130 even higher than the height of the battery module 100, the upper cover 1200 fastened to the upper surface of the cross beam 1130 and the battery module 100 can be separated at a predetermined interval. In this way, the cross beam 1130 can be coupled with the upper cover 1200 to support the upper cover 1200 below the upper cover 1200.

[0060] The cross beam 1130 can also be manufactured by an extrusion molding method. In this case, a through channel 1132 extending along the longitudinal direction of the cross beam 1130 can be formed. Thereby, the overall weight of the cross beam 1130 can be reduced.

[0061] As shown in FIG. 5, the lower pack housing 1100 may further include a center frame 1140 that crosses the center of the bottom housing 1110. The center frame 1140 extends along the longitudinal direction of the bottom housing 1110 and is installed at the center thereof. Thereby, the longitudinal rigidity of the battery pack 1000 can be further improved. Also, the battery modules 100 arranged with the center frame 1140 interposed therebetween can be separated to prevent an undesirable short circuit therebetween.

[0062] As shown in FIGS. 4 to 6, the upper cover 1200 includes a first upper cover 1210 and a second upper cover 1220.

[0063] As shown in FIGS. 5 and 6, the first upper cover 1210 faces the battery module 100 and is partially coupled to the second upper cover 1220.

[0064] The first upper cover 1210 can be disposed below the second upper cover 1220.

[0065] The thicknesses of the first upper cover 1210 and the second upper cover 1220 can be set to be different. 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 if a strong external impact is applied to the upper cover 1200 and the second upper cover 1220 is damaged, the first upper cover 1210 can protect the battery module 100 from the external impact. Or, the thickness of the second upper cover 1220 may be even greater than the thickness of the first upper cover 1210. In this case, even if a strong external force is applied to the upper cover 1200, the second upper cover 1220 itself can protect the battery module 100 or the battery pack 1000 from the external force with its own rigidity.

[0066] The first upper cover 1210 can be manufactured as a flat plate having a shape corresponding to the edge shape of the bottom housing 1110. For example, if the bottom housing 1110 is rectangular, the first upper cover 1210 can also 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 can cover the accommodation space S and airtightly close the inside of the battery pack 1000.

[0067] The first upper cover 1210 is fastened to the upper surfaces of the side wall housing 1120 and the cross beam 1130. At this time, since the height of the cross beam 1130 is even higher than the height of the battery module 100, the first upper cover 1210 is arranged to be spaced apart from the battery module 100 as shown in FIG. 6.

[0068] In the conventional battery pack 10, since the fireproof member 13 was installed on the inner surface of the upper cover 12 facing the battery module 1, there was a problem that the fireproof member 13 blocked the venting hole 1a of the battery module 1 in a situation where high-temperature gas jetted out. However, in the present embodiment, as shown in FIG. 6, the lower surface 1211 of the first upper cover faces the upper surface 130 of the battery module. That is, on the surface of the first upper cover 1210 facing the battery module, even if high-temperature gas is released from the battery module 100, a member that blocks the venting hole of the battery module is not installed. Therefore, it is possible to prevent risks (such as heat transfer to adjacent battery cells, explosion of the battery module, etc.) that may occur due to the blocking of the venting hole. Also, when the battery module 100 shown in FIG. 3 is installed, since no separate fireproof member is provided on the lower surface 1211 of the first upper cover, damage to the battery cell 111 due to a deformed fireproof member does not occur.

[0069] By the first upper cover 1210, the battery module 100 is isolated in the sealed space between the cross beams 1130. Therefore, even if gas jets out from a specific battery module 100, the high-temperature gas is not transmitted to the battery module 100 located beyond the cross beam 1130.

[0070] As shown in FIGS. 4 to 6, the second upper cover 1220 is separated from the first upper cover 1210 at least in part so as to have a heat insulation layer I between the first upper cover 1210. For example, the second upper cover 1220 may be joined at the edge portion with the first upper cover 1210, and at least a part of the central portion may be separated. At this time, the separated space between the first upper cover 1210 and the second upper cover 1220 may be the heat insulation layer I.

[0071] The heat insulation layer I can be an air layer between the first upper cover 1210 and the second upper cover 1220. Or it can be a vacuum space having a predetermined degree of vacuum. Thus, by providing the heat insulation layer I inside the upper cover 1200, heat transfer towards the upper part of the battery pack 1000 can be minimized without separately applying a refractory member to the lower surface 1211 of the first upper cover. Also, when the battery pack 1000 is installed at the lower part of a vehicle, heat transfer of high temperature to a passenger boarding the vehicle can be minimized.

[0072] As shown in FIGS. 5 and 6, a heat insulating member 200 can be installed in the heat insulation layer I to further minimize heat transfer towards the upper part of the battery pack 1000.

[0073] As shown in FIGS. 5 and 6, the heat insulating member 200 is disposed on the surface of the first upper cover 1210 facing the heat insulation layer I. That is, it is installed inside the upper cover 1200. Thereby, even if high-temperature gas jets out from the battery cell 111 or the battery module 100, the first upper cover 1210 can block between the heat insulating member 200 and the battery module 100 to minimize thermal deformation of the heat insulating member 200.

[0074] As shown in FIG. 5, the heat insulating member 200 can be a heat insulating block or a heat insulating sheet having a rectangular shape. Or the heat insulating member can be a heat-resistant resin applied to the surface of the first upper cover 1210 facing the heat insulation layer I.

[0075] Such a heat insulation member 200 may include one or more selected from the group consisting of nitrile butadiene rubber, natural rubber, fluororubber, HBR (High cis BR), styrene butadiene rubber, chloroprene rubber, ethylene propylene terpolymer (EPDM), and silicone rubber. However, in the present invention, since the heat insulation member 200 is provided in the heat insulation layer I between the first upper cover 1210 and the second upper cover 1220, the possibility of damage to the battery module 100 due to thermal deformation of the heat insulation member 200 is low. Therefore, the material of the heat insulation member 200 is not particularly limited as long as it includes a material having a low thermal conductivity and capable of delaying heat transfer.

[0076] 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 shown in FIGS. 5 and 6, it may be a plurality of members arranged at predetermined intervals along the longitudinal direction of the battery pack 1000 so as to correspond to the upper part of the battery module 100. As long as it can be installed on the first upper cover 1210 to block the heat generated from the battery module 100, the number and area of the installed heat insulation members 200 are not particularly limited.

[0077] As shown in FIGS. 4 to 6, the second upper cover 1220 may include an upper plate 1221 that is spaced apart from the first upper cover 1210 to define the heat insulation layer I, and a partition plate 1222 that is bent from the upper plate 1221 toward the first upper cover 1210.

[0078] The partition board 1222 is bent toward the first upper cover 1210 following the widthwise end of the upper plate 1221. At this time, referring to FIGS. 4 to 6, the widthwise 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 widthwise direction of the battery pack 1000. Further, as shown in FIGS. 5 and 6, the partition board 1222 has a flat surface substantially parallel to the first upper cover 1210 at the end in its extending direction. By the flat surface of the partition board 1222 coming into contact with the first upper cover 1210, the heat insulation layer I is partitioned into a plurality of sections.

[0079] As shown in FIGS. 5 and 6, the partition board 1222 can support the upper plate 1221 so that the upper plate 1221 is separated from the first upper cover 1210. Therefore, even if an external impact is applied to the upper plate 1221, the upper plate 1221 and the subsequent partition board 1222 can disperse the external impact or the vibration caused by the external impact. Further, the overall durability and structural rigidity of the second upper cover 1220 can be improved.

[0080] Also, since the heat insulation layer I is partitioned into a plurality of sections by the partition board 1222, for example, even if one section of the heat insulation layer I overheats, heat transfer to the heat insulation layer I of other adjacent sections can be blocked by the partition board 1222. That is, even if a thermal runaway occurs in the module below a specific heat insulation layer I and the specific heat insulation layer I overheats, heat transfer from the specific heat insulation layer I to other adjacent heat insulation layers can be blocked by the partition board 1222. Therefore, the partition board 1222 can also play a role in preventing heat propagation to adjacent modules.

[0081] The partition board 1222 can be fixed to the cross beam 1130 together with the first upper cover 1210. For example, as shown in FIGS. 5 to 6, a plurality of fastening members B penetrate through the second through hole H2 of the partition board 1222 and the first through hole H1 of the first upper cover 1210, and are coupled to the fastening groove 1131 of the cross beam 1130, whereby the partition board 1222 and the first upper cover 1210 can be fastened to the cross beam 1130. In this case, in order to maintain the airtightness or watertightness of the battery pack, a sealing member (not shown) such as an O-ring may be interposed between the fastening member B and the through holes H1 and H2. Such a fastening member B can be a bolt.

[0082] However, the present invention is not limited to this, and as long as the partition board 1222 and the first upper cover 1210 can be fixed to the cross beam 1130, the coupling means is not particularly limited. For example, the partition board 1222 and the first upper cover 1210 can be welded and coupled, and the coupled partition board 1222 and first upper cover 1210 can be welded or fastened to the cross beam 1130.

[0083] The battery pack 1000 of the present embodiment includes the upper cover 1200 provided with the heat insulation layer I, so that it is not necessary to separately install a fireproof member in the accommodation space of the battery module as in the prior art. Therefore, damage or explosion of the battery module 100 or the battery cell 111 due to deformation of the fireproof member can be prevented. Further, a heat insulating member 200 can be installed inside the heat insulation layer I to prevent heat from being transmitted to the upper part of the battery pack 1000.

[0084] However, if gas continuously jets out from the battery module 100, the pressure in the accommodation space S may excessively increase, causing an explosion of the battery pack 1000. Therefore, when the gas jetted out from the battery module 100 accumulates to a certain extent in the accommodation space S, means for jetting it to the outside of the battery pack 1000 is necessary.

[0085] FIG. 7 is a schematic diagram showing the gas discharge path P of the present embodiment.

[0086] As shown in FIG. 7, the side wall housing 1120 may include a side wall communication hole 1122 that communicates the accommodation space S with the hollow channel 1121 on the surface facing the accommodation space S. Further, each side wall housing 1120 installed along the edge of the bottom housing 1110 is installed such that the internal hollow channels 1121 communicate with each other. Therefore, when high-temperature gas jets from the battery module 100 into the accommodation space S, the high-temperature gas flows into the hollow channel 1121 of the side wall housing 1120 facing the battery module 100 through the side wall communication hole 1122 and can flow into the hollow channels 1121 of other side wall housings 1120.

[0087] As shown in FIG. 7, the side wall housing 1120 may include a gas discharge hole (not shown) that communicates the hollow channel 1121 with the outside, and a venting device 1122a installed in the gas discharge hole.

[0088] The venting device 1122a may include a venting cap for preventing the outflow of gas in the gas discharge hole. Further, a gas sealing member may be installed in the gas discharge hole or the venting cap. The gas sealing member is, for example, a sheet-shaped member that deforms at a predetermined pressure and / or above a predetermined temperature to open the gas outlet to the outside. For example, the gas sealing member may be a rupture sheet configured to rupture when the pressure of the venting gas becomes a certain pressure or more. Alternatively, the sheet member may open the gas outlet while melting at a predetermined temperature or more. For this purpose, the sheet member may be provided with a film or foam substance that is vulnerable to high temperatures. Therefore, when high-temperature gas accumulates in the hollow channel 1121 and the pressure and / or temperature of the hollow channel 1121 rises above a predetermined value, the gas sealing member can open the gas discharge hole to discharge the high-temperature gas to the outside.

[0089] The gas discharge path P shown in FIG. 7 exemplarily shows one of various gas discharge paths for the sake of illustration. The gas discharge path is not particularly limited as long as it can discharge the gas in the accommodation space to the outside.

[0090] (Second Embodiment) FIG. 8 is a perspective view of the battery pack 2000 according to the second embodiment of the present invention, and FIG. 9 is a cross-sectional view of the battery pack 2000 taken along line B-B' of FIG. 8.

[0091] Even if the high-temperature gas ejected into the accommodation space S is discharged to the outside of the battery pack 2000 through the side wall housing 1120, the high-temperature gas can transfer heat to the first upper cover 2210 or the second upper cover 2220 during the discharge process to heat the upper cover 2200. When the upper cover 2200 is heated, the air layer of the internal heat insulation layer I thereof can also be heated. In this case, due to a rapid temperature rise, the air expands and the second upper cover 2220 may be detached from the first upper cover 2210, etc., and the upper cover 2200 may be damaged.

[0092] 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 that communicate the heat insulation layer I with the outside of the battery pack 2000.

[0093] The battery pack 2000 of the present embodiment can discharge the heated air from the heat insulation layer I through the upper discharge holes 2223, and can prevent the upper cover 2200 from being damaged due to the air expansion of the heat insulation layer I. Further, the heated air of the heat insulation layer I can be discharged to the outside through the upper discharge holes 2223, and relatively cold air can be made to flow into the heat insulation layer I to circulate the air of the heat insulation layer I. In this way, even if the air of the heat insulation layer I is heated, the air is circulated through the upper discharge holes 2223, and the air of the heat insulation layer I can be cooled. Further, even if the upper discharge holes 2223 are provided, since the first upper cover 2210 closes the accommodation space S, the airtightness or watertightness inside the battery pack is not significantly impaired.

[0094] 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 facing the heat insulation layer I so that the heat insulation layer I can communicate with the outside. The upper discharge hole 2223 may have a circular, elliptical, square, cross-shaped, or a combined shape thereof when viewed from the top of the battery pack 2000.

[0095] As shown in FIGS. 8 and 9, a plurality of upper discharge holes 2223 may be provided in the upper plate 2221.

[0096] However, if the upper discharge hole 2223 is always open, unintended fluid may enter the battery pack 2000 through various paths. Or, foreign matter that has entered through the upper discharge hole 2223 may damage (corrode, contaminate, etc.) the first upper cover 2210. In this case, the airtightness and watertightness of the battery pack 2000 are not maintained, and unexpected failures may occur during the use of the battery pack 2000. To prevent this, an upper discharge member 2223a may be installed in the upper discharge hole 2223.

[0097] The upper discharge member 2223a can close the upper discharge hole 2223 and hermetically seal the heat insulation layer I. However, when the air in the heat insulation layer I is heated by the high-temperature gas discharged from the battery module 100 and the temperature inside the heat insulation layer I rises above a predetermined temperature, the upper discharge member 2223a may rupture or break, allowing the heat insulation layer I to communicate with the outside of the battery pack. When the upper discharge hole 2223 is opened, the heated air inside the heat insulation layer I is discharged as described above, and outside air can flow in to cool the heat insulation layer I.

[0098] The upper discharge member 2223a may be configured similarly to the venting device 1122a of the first embodiment described above. For example, a sheet-shaped gas sealing member may be installed in the upper discharge hole 2223.

[0099] In this way, the upper cover 2200 of the present embodiment can selectively discharge the heated air in the heat insulation layer I only under the condition that the temperature is equal to or higher than a predetermined temperature without immediately discharging it. The predetermined temperature condition can be selected within a suitable range in consideration of the safety of the passengers on board the vehicle.

[0100] Further, the predetermined condition under which the upper discharge member 2223a ruptures or is damaged may be different from the predetermined condition under which the venting device 1122a opens the gas discharge hole. For example, the upper discharge member 2223a may rupture at a temperature lower than the temperature at which the venting device 1122a opens the gas discharge hole to open the upper discharge hole 2223.

[0101] According to the present embodiment, when the temperature of the heat insulation layer I rises excessively, the heated air can be discharged from the heat insulation layer I to prevent deformation and damage of the second upper cover 2220 or the upper cover 2200 due to air expansion, and the heat insulation layer I can be cooled. Further, by installing the upper discharge member 2223a in the upper discharge hole 2223, the heated air can be selectively discharged only in a specific situation where the temperature of the heat insulation layer I rises above a predetermined temperature.

[0102] Configurations overlapping with those of the other first embodiment can also be applied in the same manner in the present embodiment. For example, as shown in FIG. 9, the lower surface 2211 of the first upper cover and the upper surface 130 of the battery module can directly face each other, and the second upper cover 2200 may include an upper plate 2221 and a partition plate 2222.

[0103] The above description merely exemplarily explains the technical idea of the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the drawings disclosed in the present invention are for the purpose of explanation rather than for limiting the technical idea of the present invention, and the scope of the technical idea of the present invention is not limited by such drawings. The protection scope of the present invention should be interpreted by the scope of the claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

[0104] On the one hand, terms indicating directions such as up, down, left, right, front, and back are used in this specification. However, these terms are for convenience of explanation and it is obvious that they can vary depending on the position of the object in question, the position of the observer, etc.

Explanation of Reference Numerals

[0105] 1: Conventional battery module 10: Conventional battery pack 11: Lower pack housing of the conventional battery pack 12: Upper cover of the conventional battery pack 13: Fire-resistant member 100: Battery module 1000, 2000: Battery pack 1100: Lower pack housing 1110: Bottom housing 1120: Side wall housing 1130: Cross beam 1140: Center frame 1200, 2200: Upper cover 1210, 2210: First upper cover 1220, 2220: Second upper cover I: Heat insulation layer

Claims

1. A battery module; a lower pack housing having an accommodation space in which the battery module is installed; an upper cover coupled to an upper portion of the lower pack housing to cover the receiving space, The upper cover is a first upper cover facing the battery module; a second upper cover at least partially spaced apart from the first upper cover to have a thermal insulating layer between the first upper cover and the second upper cover.

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

3. The battery pack of claim 1 , wherein the second upper cover includes a plurality of upper exhaust holes for allowing the insulating layer to communicate with the outside.

4. The second upper cover is 4. The battery pack of claim 3, further comprising an upper exhaust member that closes the upper exhaust hole to hermetically seal the insulation layer and that bursts to connect the insulation layer to the outside when a temperature inside the insulation layer rises to or above a predetermined temperature.

5. The second upper cover is 5. The battery pack of claim 1, further comprising: an upper plate separated from the first upper cover; and a partition plate connected to a widthwise end of the upper plate and bent from the upper plate toward the first upper cover so as to divide the insulating layer into a plurality of parts.

6. The lower pack housing includes: a bottom housing for supporting a lower surface of the battery module; and a cross beam for dividing the accommodating space into a plurality of sections and for supporting a side surface of the battery module, The battery pack of claim 1 , wherein the cross beam is coupled to the top cover.

7. The battery pack of claim 1 , wherein a thickness of the first top cover is different from a thickness of the second top cover.

8. The lower pack housing includes: a bottom housing supporting a lower surface of the battery module; and a side wall housing disposed along an edge of the bottom housing, The side wall housing includes: With a hollow channel inside, The battery pack according to claim 1 , further comprising a side wall communication hole on a surface facing the accommodation space, the side wall communication hole communicating the accommodation space with the hollow channel.

9. The battery pack according to claim 1 , further comprising an insulating member disposed on the insulating layer.

10. The battery pack according to claim 9 , wherein the insulating member is an insulating block disposed on a surface of the first upper cover facing the insulating layer.

11. The battery module includes: a battery cell stack in which a plurality of battery cells are stacked; a bus bar frame coupled to the battery cell stack at a front surface and a rear surface in a longitudinal direction of the battery cell stack; 5. The battery pack of claim 1, wherein the battery cell stack has open top and bottom surfaces.

12. The battery pack according to claim 1 , further comprising a thermally conductive resin layer interposed between the lower surface of the battery module and the lower pack housing.

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