Battery pack and device including same

Abstract

A battery pack according to one embodiment of the present invention includes a battery module including a plurality of battery cells, and a pack frame that houses the battery module. The battery modules are arranged in a row along the width direction within the pack frame to form a battery module group, and the battery cells are stacked along the width direction within the battery module to form a battery cell stack. A cover member that covers the entire top surface of the battery module group is located between the top surface of the battery module group and the pack frame.

Description

[Technical field]

[0001] Cross-reference to related applications This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0051382 filed on April 20, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery pack and a device including the same, and more particularly to a battery pack and a device including the same that have improved safety against flame occurrence. [Background technology]

[0003] In modern society, as the use of portable devices such as mobile phones, notebook computers, camcorders, and digital cameras has become commonplace, there has been active development of technology related to such mobile devices. In addition, rechargeable secondary batteries are a solution to address air pollution caused by existing gasoline-powered vehicles that use fossil fuels, and are used as the power source for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), etc., so there is an increasing need for the development of secondary batteries.

[0004] Currently, commercial secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Of these, lithium secondary batteries are in the spotlight for their advantages over nickel-based secondary batteries, such as almost no memory effect, freedom in charging and discharging, a very low self-discharge rate, and high energy density.

[0005] Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as positive and negative active materials, respectively, and include an electrode assembly in which positive and negative plates coated with the positive and negative active materials are arranged with a separator between them, and a battery case that hermetically houses the electrode assembly together with an electrolyte.

[0006] In general, lithium secondary batteries can be classified into can-type secondary batteries in which an electrode assembly is housed in a metal can and pouch-type secondary batteries in which an electrode assembly is housed in a pouch made of an aluminum laminate sheet, depending on the shape of the exterior material.

[0007] In the case of a secondary battery used in a small device, two or three battery cells are arranged, whereas in the case of a secondary battery used in a medium to large device such as an automobile, a battery module in which a plurality of battery cells are electrically connected is used. In such a battery module, a plurality of battery cells are connected to each other in series or parallel to form a battery cell stack, thereby improving capacity and output. In addition, one or more battery modules may be mounted with various control and protection systems such as a BMS (Battery Management System) and a cooling system to form a battery pack.

[0008] In a battery pack made up of multiple battery modules, the heat generated from the multiple battery cells can be combined in a small space, causing the temperature to rise rapidly and sharply. In other words, a battery module in which multiple battery cells are stacked and a battery pack equipped with such a battery module can obtain high output, but it is not easy to remove the heat generated in the battery cells during charging and discharging. If the heat of the battery cells is not properly dissipated, the battery cells deteriorate faster, their lifespan is shortened, and the possibility of explosion or fire increases.

[0009] Furthermore, battery modules included in vehicle battery packs are frequently exposed to direct sunlight and may be placed in high temperature conditions such as in summer or in desert regions. In addition, since multiple battery modules are arranged in a concentrated manner to increase the mileage of a vehicle, flames or heat generated in any one battery module may easily spread to adjacent battery modules, which may ultimately lead to the battery pack itself catching fire or exploding.

[0010] Therefore, it is necessary to design a model that will not lead to a fire or explosion of the battery pack itself even if a thermal runaway phenomenon occurs in any one battery cell. Summary of the Invention [Problem to be solved by the invention]

[0011] An object of the present invention is to provide a battery pack and a device including the same, which can prevent a thermal runaway phenomenon from leading to a fire or explosion even if the thermal runaway phenomenon occurs in any one of the battery cells.

[0012] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0013] A battery pack according to an embodiment of the present invention includes a battery module including a plurality of battery cells, and a pack frame that houses the battery module. Inside the pack frame, the battery modules are arranged in a row along a width direction to form a battery module group, and inside the battery module, the battery cells are stacked along the width direction to form a battery cell stack. A cover member that covers the entire top surface of the battery module group is located between the top surface of the battery module group and the pack frame.

[0014] The battery cells may be stacked along the width direction in an upright state such that one surface of the cell body of the battery cell is perpendicular to the bottom of the pack frame.

[0015] The battery cell may be a pouch-type battery cell.

[0016] The battery module group may include a first battery module group and a second battery module group spaced apart from each other along the width direction.

[0017] The cover member may include a first cover member covering an upper surface of the first battery module group and a second cover member covering an upper surface of the second battery module group.

[0018] The first cover member may be disposed so as to correspond to the entire upper surface of the first battery module group.

[0019] The second cover member may be disposed so as to correspond to the entire upper surface of the second battery module group.

[0020] The pack frame may include a partition portion located between the first battery module group and the second battery module group.

[0021] The battery pack may further include a connecting member connecting adjacent ones of the battery modules. Effect of the Invention

[0022] According to an embodiment of the present invention, even if a thermal runaway phenomenon occurs in any one battery cell, thermal propagation is designed to occur sequentially, thereby preventing fire or explosion in the battery pack.

[0023] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief description of the drawings]

[0024] [Figure 1] 1 is a perspective view showing a battery module and a connecting member according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an exploded perspective view of the battery module of FIG. [Diagram 3] 3 is a perspective view of a battery cell included in the battery module of FIG. 2. [Figure 4] 1 is a cross-sectional view of a battery pack according to an embodiment of the present invention; [Diagram 5] 5 is a cross-sectional view that shows a schematic representation of a state in which a thermal runaway phenomenon occurs in one of the battery cells in the battery pack of FIG. 4. [Figure 6] 11 is a cross-sectional view of a battery pack according to another embodiment of the present invention. [Figure 7] 7 is a cross-sectional view that illustrates a state in which a thermal runaway phenomenon occurs in one of the battery cells in the battery pack of FIG. 6. [Figure 8] 10 is a cross-sectional view of a battery pack including a partition according to a modified embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may, however, be embodied in various different forms and should not be construed as being limited to the embodiments set forth herein.

[0026] In order to clearly explain the present invention, parts that are not necessary for the explanation will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0027] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, the thicknesses of various layers and regions are exaggerated to clearly express the layers and regions. In the drawings, the thicknesses of some layers and regions are exaggerated to facilitate explanation.

[0028] In addition, when a part such as a layer, film, region, or plate is said to be "on" or "above" another part, this includes not only the case where it is "directly on" another part, but also the case where there is another part in between. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between. In addition, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" the direction against gravity.

[0029] Additionally, throughout the specification, when a part is said to "comprise" a certain element, this means that it may further include other elements, but not excluding other elements, unless specifically stated to the contrary.

[0030] Also, throughout the specification, the term "in a plane" means when the subject part is viewed from above, and the term "in cross section" means when the subject part is cut vertically and viewed from the side.

[0031] Fig. 1 is a perspective view showing a battery module and a connecting member according to an embodiment of the present invention, Fig. 2 is an exploded perspective view of the battery module of Fig. 1, Fig. 3 is a perspective view of a battery cell included in the battery module of Fig. 2.

[0032] 1 to 3, a battery module 100 according to an embodiment of the present invention includes a plurality of battery cells 110. The battery cells 110 are preferably pouch-type battery cells and may be formed in a rectangular sheet-type structure. For example, the battery cell 110 according to this embodiment has a structure in which two electrode leads 111 and 112 face each other and protrude from one end and the other end, respectively.

[0033] 3, the battery cell 110 according to this embodiment has two electrode leads 111 and 112 that face each other and protrude from one end 114a and the other end 114b of a cell body 113. More specifically, the electrode leads 111 and 112 are connected to an electrode assembly (not shown) and protrude from the electrode assembly (not shown) to the outside of the battery cell 110.

[0034] Meanwhile, the battery cell 110 can be manufactured by bonding both ends 114a, 114b of the cell case 114 and one side 114c connecting them in a state where an electrode assembly (not shown) is housed in the cell case 114. In other words, the battery cell 110 according to this embodiment has a total of three sealing parts 114sa, 114sb, and 114sc, and the sealing parts 114sa, 114sb, and 114sc are structured to be sealed by a method such as heat fusion, and the other side can be formed as the connecting part 115. The cell case 114 can be formed of a laminate sheet including a resin layer and a metal layer.

[0035] In addition, the connecting portion 115 extends long along one edge of the battery cell 110, and a protrusion 110p of the battery cell 110 called a bat-ear may be formed at an end of the connecting portion 115. However, the protrusion 110p is only one exemplary structure, and a battery cell 110 according to another embodiment of the present invention may have a shape in which the connecting portion 115 extends in a straight line without any protrusion.

[0036] FIG. 3 only describes a battery cell 110 having electrode leads 111, 112 protruding in both directions. However, as another embodiment of the present invention, a unidirectional pouch-type battery cell in which electrode leads both protrude in one direction is also possible.

[0037] A plurality of such battery cells 110 may be configured, and the plurality of battery cells 110 may be stacked so as to be electrically connected to each other to form a battery cell stack 120. In particular, as shown in Fig. 2, the plurality of battery cells 110 may be stacked along a direction parallel to the y-axis. Thus, one electrode lead 111 of the battery cell 110 may protrude toward the x-axis direction, and another electrode lead 112 may protrude toward the -x-axis direction.

[0038] The battery cell stack 120 may be housed in a module frame 200. The module frame 200 may be a metal frame with both sides open. More specifically, the module frame 200 is open in both directions in which the electrode leads 111 and 112 protrude with respect to the battery cell stack 120. However, the module frame 200 shown in FIG. 2 is only an exemplary structure, and there is no particular limitation on the shape of the module frame 200 as long as it can house the battery cell stack 120. For example, a shape in which an upper cover is joined to a U-shaped frame with an open top, a shape in which a U-shaped frame and an upside-down U-shaped frame are joined to each other, etc. are possible.

[0039] End plates 410 and 420 may be disposed on both open sides of the module frame 200. The two end plates 410 and 420 are referred to as a first end plate 410 and a second end plate 420, respectively. The end plates 410 and 420 may cover both open sides of the module frame 200. The battery cell stack 120 is accommodated in a space formed by the module frame 200 and the end plates 410 and 420, so that the battery cell stack 120 can be physically protected. To this end, the module frame 200 and the end plates 410 and 420 may include a metal material having a certain strength, such as aluminum, or a plastic material. Meanwhile, the module frame 200 and the end plates 410 and 420 may be joined by a method such as welding while corresponding corners are in contact with each other. However, this is an exemplary method, and bolt fastening, hook fastening, etc. may be applied as a mechanical connection form.

[0040] Meanwhile, the battery module 100 according to the present embodiment may further include a bus bar frame 300 to which the bus bars 510 and the terminal bus bars 520 are attached.

[0041] The busbar 510 and the terminal busbar 520 may be joined to the electrode leads 111, 112 of the battery cells 110 to electrically connect the plurality of battery cells 110. Specifically, the busbar frames 300 to which the busbars 510 and the terminal busbars 520 are attached may be disposed on one side (x-axis direction) and the other side (-x-axis direction) of the battery cell stack 120, respectively. In other words, any one of the busbar frames 300 may be disposed between any one of the end plates 410, 420 and the battery cell stack 120. In FIG. 2, the busbar frame located on the other side (-x-axis direction) of the battery cell stack 120 is omitted from illustration.

[0042] A lead slit is formed in the bus bar frame 300, and the electrode leads 111, 112 can be bent after passing through the lead slit and joined to the bus bar 510 and the terminal bus bar 520. As long as a physical and electrical connection is possible, there is no particular limitation on the joining method, and welding can be used as an example.

[0043] Meanwhile, a portion of the terminal bus bar 520 may be exposed to the outside of the battery module 100. Specifically, a first terminal bus bar opening 410H is formed in the first end plate 410 to expose a portion of the terminal bus bar 520. The exposed portion of the terminal bus bar 520 may be joined to a connection member 1400 as shown in FIG. 1 in order to form a HV (High Voltage) connection by being connected to another battery module or a BDU (Battery Disconnect Unit). That is, the battery module 100 may be connected to another battery module or a BDU (Battery Disconnect Unit) through the connection member 1400. Here, the HV connection is a connection that serves as a power source for supplying power, and refers to a connection between battery cells or a connection between battery modules.

[0044] There are no particular limitations on the material of the connecting member 1400 as long as it is capable of electrical connection, and a metal material can be used.

[0045] The battery pack 1000a according to an embodiment of the present invention will be described in detail below with reference to FIG.

[0046] 4 is a cross-sectional view of a battery pack according to an embodiment of the present invention, specifically, a battery pack 1000a in which the battery module 100 shown in FIGS. 1 and 2 is housed in a pack frame 1200 is cut along a yz plane.

[0047] 2 to 4, a battery pack 1000a according to an embodiment of the present invention includes a battery module 100 including a plurality of battery cells 110, and a pack frame 1200 that houses the battery module 100. In this embodiment, the battery module 100 may be the battery module 100 shown in FIGS. 1 and 2. In FIG. 4, the battery cells 110 included in the battery module 100 are roughly represented by dotted lines for the sake of convenience. In addition, the battery modules 100 may be electrically connected to each other by a connecting member 1400 to form an HV connection. In FIG. 4, the connecting member 1400 is roughly represented, unlike in FIG. 1.

[0048] The pack frame 1200 may include an upper frame 1210 and a lower frame 1220. The upper frame 1210 may be in a plate shape, and the lower frame 1220 may be in a shape that includes a bottom 1200 on which the battery module 100 is placed and has an open top. The upper frame 1210 is placed on the open top of the lower frame 1220, and the upper frame 1210 and the lower frame 1220 are joined at corresponding corners to complete the pack frame 1200. The space between the upper frame 1210 and the lower frame 1220 is the space in which the battery module 100 is accommodated. However, the above structure is an exemplary structure of the pack frame 1200 according to the present embodiment, and it goes without saying that modified forms are possible as long as the battery module 100 can be accommodated therein.

[0049] Inside the pack frame 1200, the battery modules 100 are arranged in a row along the width direction d1 to form a battery module group 100G. Inside the battery module 100, the battery cells 110 are stacked along the width direction d1 to form a battery cell stack. In this specification, the width direction d1 is one of the directions parallel to the ground or one surface of the bottom 1200F of the pack frame 1200, in other words, one of the directions parallel to the xy plane.

[0050] More specifically, the battery cells 110 can be stacked along the width direction d1 in an upright state in which one surface of the cell body 113 of the battery cell 110 is perpendicular to one surface of the bottom 1200F of the pack frame 1200. That is, the direction in which the battery modules 100 are arranged in the battery module groups 100Ga and 100Gb can coincide with the direction in which the battery cells 110 are stacked.

[0051] Meanwhile, the battery pack 1000a according to the present embodiment includes a cover member 1300. The cover member 1300 covers the entire upper surface of the battery module group 100G and is located between the upper surface of the battery module group 100G and the pack frame 1200. Specifically, the cover member 1300 may be disposed between the upper surface of the battery module group 100G and the upper frame 1210.

[0052] As an example, the cover member 1300 may be in a plate shape as shown in Fig. 4. However, there is no limitation on the shape of the cover member 1300 as long as it covers the entire upper surface of the battery module group 100G. For example, a structure in which beads are formed to ensure rigidity other than a plate shape is also possible, and a shape in which other electrical components are arranged is also possible.

[0053] Although there is no particular restriction on the material of the cover member 1300, it is preferable that the cover member 1300 contains a material having heat resistance because it is necessary to suppress heat propagation. The suppression of heat propagation by the cover member 1300 will be described later.

[0054] Hereinafter, with reference to FIGS. 3 to 5, advantages of the battery pack 1000a according to the present embodiment when a thermal runaway phenomenon occurs in any one of the battery cells will be described.

[0055] FIG. 5 is a cross-sectional view that illustrates a state in which a thermal runaway phenomenon occurs in one of the battery cells in the battery pack of FIG.

[0056] 3 to 5, a thermal runaway phenomenon may occur in one of the battery cells 110 included in the battery pack 1000a according to the present embodiment. An example of a thermal runaway phenomenon is as follows. Physical, thermal, and electrical damage may occur to the battery cell 110, including overcharging, and the internal pressure of the battery cell 110 may increase. If the fusion strength limit of the cell case 114 of the battery cell 110 is exceeded, high temperature heat, venting gas, and the like generated in the battery cell 110 may be ejected to the outside of the battery cell 110.

[0057] A thermal runaway phenomenon occurring in any one battery cell may spread to adjacent battery cells and even to adjacent battery modules due to heat transfer effects, i.e., effects of conduction, convection, radiation, etc. In particular, due to the structure of a battery pack in which battery modules are closely packed to increase space utilization, the thermal runaway phenomenon does not propagate sequentially to the battery modules, but occurs simultaneously in multiple closely packed battery modules. In other words, a thermal runaway phenomenon that starts from a battery cell and spreads simultaneously to multiple battery modules can lead to the battery pack itself catching fire or exploding, which is a serious problem.

[0058] However, in the battery pack 1000a according to the present embodiment, the battery modules 100 in the battery module group 100G are arranged in a row along the width direction d1, and a cover member 1300 is positioned to cover the entire upper surface of the battery module group 100G, so that the propagation of the thermal runaway phenomenon occurs not only in units of the battery modules 100 but also in units of the battery cells 110 in sequence. That is, as shown in FIG. 5, when a thermal runaway phenomenon occurs in any one battery cell in any one battery module, venting gas and heat are propagated in sequence to the adjacent battery cells 110. As an example, FIG. 5 shows the propagation of the thermal runaway phenomenon to the battery cell 110' of the leftmost battery module and the battery cell 110" of the third battery module from the left.

[0059] In addition, the venting gas and heat are prevented from immediately propagating to other battery modules that are not adjacent to the cover member 1300. In this embodiment, a heat insulating structure is designed so that the thermal runaway phenomenon does not propagate between the battery modules 100 by skipping the HV connection order of the connection member 1400.

[0060] As described above, by designing the sequential propagation, the time for the venting gas and heat to propagate can be increased, and the intensity of the thermal runaway gradually decreases or does not increase during the sequential propagation. That is, the battery pack 1000a according to the present embodiment can prevent the battery pack 1000a from catching fire or exploding even if a thermal runaway phenomenon occurs in any one of the battery cells 110. If the cover member 1300 is not provided or the battery modules 100 are not arranged in a row along the width direction d1, the thermal runaway phenomenon that started in any one of the battery cells 110 may immediately propagate to other battery modules that are not adjacent to each other, and a large amount of venting gas and high-temperature heat may be discharged from the battery modules 100 in a short time. This is likely to lead to the battery pack 1000a catching fire or exploding.

[0061] Meanwhile, as described above, in the present embodiment, the direction in which the battery modules 100 are arranged in the battery module group 100G can coincide with the direction in which the battery cells 110 are stacked. This allows the thermal runaway phenomenon to propagate sequentially between the battery cells 110 in the battery module 100. By aligning the arrangement direction of the battery modules 100 with the stacking direction of the battery cells 110, it is intended to further delay the propagation of the thermal runaway phenomenon.

[0062] Hereinafter, a battery pack 1000b according to another embodiment of the present invention will be described in detail with reference to FIG.

[0063] 6 is a cross-sectional view of a battery pack according to another embodiment of the present invention. Like FIG. 4, this shows a state in which the battery pack 1000b in which the battery module 100 shown in FIG. 1 and FIG. 2 is housed in a pack frame 1200 is cut along the yz plane.

[0064] 2, 3 and 6, a battery pack 1000b according to an embodiment of the present invention may include a battery module 100 including a plurality of battery cells 110 and a pack frame 1200 that houses the battery module 100. In this embodiment, the battery module 100 may be the battery module 100 shown in Figures 1 and 2. In Figure 6, the battery cells 110 included in the battery module 100 are roughly represented by dotted lines for ease of explanation.

[0065] In addition, the battery pack 1000b may further include a connecting member 1400 that connects adjacent battery modules among the battery modules 100. The battery modules 100 may be electrically connected to each other through the connecting member 1400 to form an HV connection. In FIG. 6, the connecting member 1400 is illustrated in a schematic manner, unlike FIG. 1.

[0066] The pack frame 1200 may include an upper frame 1210 and a lower frame 1220. In this case, the lower frame 1220 may further include a partition wall portion 1200W. The partition wall portion 1200W will be described in detail again together with the first to third battery modules 100Ga, 100Gb, and 100Gc.

[0067] The battery modules 100 according to the present embodiment are arranged in a row along the width direction d1 to form a battery module group 100G, which may include a first battery module group 100Ga, a second battery module group 100Gb, and a third battery module group 100Gc. There is no particular limit to the number of battery module groups 100G. As shown in FIG. 6, three battery module groups 100Ga, 100Gb, and 100Gc or four or more battery module groups are also possible, and two battery module groups are also possible.

[0068] The first battery module group 100Ga, the second battery module group 100Gb, and the third battery module group 100Gc can be spaced apart from each other along the width direction d1. That is, the first battery module group 100Ga can be positioned at a distance from the second battery module group 100Gb, and the second battery module group 100Gb can be positioned at a distance from the third battery module group 100Gc.

[0069] The battery pack 1000b according to the present embodiment may include a cover member 1300, and the cover member 1300 may include a first cover member 1300a, a second cover member 1300b, and a third cover member 1300c. The first cover member 1300a covers the entire upper surface of the first battery module group 100Ga, the second cover member 1300b covers the entire upper surface of the second battery module group 100Gb, and the third cover member 1300c covers the entire upper surface of the third battery module group 100Gc. More specifically, the first cover member 1300a may be disposed to correspond to the entire upper surface of the first battery module group 100Ga. The second cover member 1300b may be disposed to correspond to the entire upper surface of the second battery module group 100Gb. The third cover member 1300c may also be disposed to correspond to the entire upper surface of the third battery module group 100Gc.

[0070] Meanwhile, the above-mentioned partition wall 1200W can be disposed at least in one of between the first battery module group 100Ga and the second battery module group 100Gb and between the second battery module group 100Gb and the third battery module group 100Gc. That is, the first to third battery module groups 100Ga, 100Gb, 100Gc are spatially separated and separated from each other by the partition wall 1200W.

[0071] Hereinafter, advantages of the battery pack 1000b according to the present embodiment when a thermal runaway phenomenon occurs in one of the battery cells will be described with reference to Figures 3, 6, and 7. Figure 7 is a cross-sectional view that shows a schematic diagram of a state in which a thermal runaway phenomenon occurs in one of the battery cells in the battery pack of Figure 6.

[0072] 3, 6 and 7, a thermal runaway phenomenon may occur in one of the battery cells 110 included in the battery pack 1000b according to the present embodiment. For example, the thermal runaway phenomenon may occur in one of the battery cells included in the right battery module of the first battery module group 100Ga.

[0073] A thermal runaway phenomenon that occurs in any one battery cell may spread to an adjacent battery cell due to the convection effect, and may further spread to an adjacent battery module. In particular, due to the structure of a battery pack in which battery modules are closely packed together to increase space utilization, the thermal runaway phenomenon may not propagate sequentially to the battery modules, but may occur simultaneously in multiple closely packed battery modules. In other words, a thermal runaway phenomenon that starts from a battery cell and spreads simultaneously to multiple battery modules may lead to the battery pack itself catching fire or exploding, which is a serious problem.

[0074] However, in the battery pack 1000b according to the present embodiment, the battery modules 100 in each of the battery module groups 100Ga, 100Gb, and 100Gc are arranged in a row along the width direction d1, and cover members 1300a, 1300b, and 1300c are positioned to cover the upper surfaces of the battery module groups 100Ga, 100Gb, and 100Gc, respectively, so that the propagation of the thermal runaway phenomenon occurs not only in units of the battery modules 100 but also in units of the battery cells 110 in sequence. That is, as shown in FIG. 7, when a thermal runaway phenomenon occurs in one battery cell in one battery module, venting gas and heat are propagated to the adjacent battery cells 110 in sequence. As an example, FIG. 7 shows the propagation of the thermal runaway phenomenon to a battery cell 110′ included in a battery module in the first battery module group 100Ga and a battery cell 110″ included in a battery module in the second battery module group 100Gb.

[0075] In addition, the cover members 1300a, 1300b, and 1300c prevent the venting gas and heat from immediately propagating to other battery module groups or battery modules that are not adjacent to each other. In this embodiment, the heat insulating structure is designed so that the thermal runaway phenomenon does not propagate between the battery modules 100 by skipping the HV connection order of the connection member 1400.

[0076] As described above, by designing for sequential propagation, the time for the venting gas and heat to propagate can be increased, and the intensity of thermal runaway can be gradually reduced or not further increased during the sequential propagation. In other words, even if a thermal runaway phenomenon occurs in any one of the battery cells 110, the battery pack 1000b according to the present embodiment can prevent the battery pack 1000b itself from catching fire or exploding.

[0077] Also, as described above, the direction in which the battery modules 100 are arranged in the battery module groups 100Ga, 100Gb, and 100Gc can be aligned with the direction in which the battery cells 110 are stacked. This allows the thermal runaway phenomenon to be propagated sequentially between the battery cells 110 in the battery module 100. By aligning the arrangement direction of the battery modules 100 with the stacking direction of the battery cells 110, it was attempted to further delay the propagation of the thermal runaway phenomenon.

[0078] At the same time, the partition wall 1200W is formed to spatially separate the battery module groups 100Ga, 100Gb, and 100Gc, and the cover members 1300a, 1300b, and 1300c are arranged to correspond to each of the battery module groups 100Ga, 100Gb, and 100Gc, so that the venting gas and heat can be transmitted sequentially not only in the battery module units but also in the battery module group units. In addition, the transmission time can be further delayed, and the effect of reducing the intensity of thermal runaway during the transmission process can be further increased. As described above, a structure with high thermal resistance can be formed by the structure that suppresses heat transmission, and when the thermal resistance is realized to a certain level or higher, the sequential transmission of thermal runaway can be terminated.

[0079] Although Fig. 6 shows a partition 1200W having a shape in which a portion of the lower frame 1220 is recessed, there is no particular limitation on the shape as long as the battery module group can be divided. As another example, Fig. 8 shows the shape of a partition 1200W' according to a modified embodiment of the present invention. Fig. 8 is a cross-sectional view of a battery pack 1000b' including a partition 1200W' according to a modified embodiment of the present invention.

[0080] 8, the partition wall 1200W' according to the present embodiment may be disposed at least one of between the first battery module group 100Ga and the second battery module group 100Gb and between the second battery module group 100Gb and the third battery module group 100Gc. The partition wall 1200W' may have a plate shape extending upward from the bottom 1200F of the lower frame 1220.

[0081] The partition wall 1200W shown in Fig. 6 and the partition wall 1200W' shown in Fig. 8 are structures capable of controlling the effects of heat transfer such as conduction, convection, and radiation, and function to prevent the spread of heat transfer. The partition walls 1200W and 1200W' may include a heat insulating material to prevent conduction, and may also include a thin metal plate material to prevent venting gas.

[0082] In this embodiment, terms indicating directions such as front, back, left, right, up, and down are used, but these terms are merely for convenience of explanation and may change depending on the position of the target object or the position of the observer, etc.

[0083] The battery pack according to the present embodiment described above may include not only the battery module but also various control and protection systems such as a Battery Management System (BMS), a Battery Disconnect Unit (BDU), and a cooling system.

[0084] The battery pack can be applied to various devices, specifically, transportation means such as electric bicycles, electric cars, and hybrids, and ESS (Energy Storage Systems), but is not limited thereto, and can be applied to various devices that can use secondary batteries.

[0085] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0086] 1000a, 1000b: Battery pack 100: Battery module 110: Battery cell 120: Battery cell stack 100G: Battery module group 1300: Cover material

Claims

1. a battery module including a plurality of battery cells; and a pack frame that houses the battery module; Within the pack frame, the battery modules are arranged in a row along a width direction to form a battery module group; The battery cells are stacked in the width direction inside the battery module to form a battery cell stack; the battery module group includes a first battery module group and a second battery module group spaced apart from each other along the width direction, a cover member positioned between the top surface of the battery module group and the pack frame, the cover member including a first cover member covering the top surface of the first battery module group and a second cover member covering the top surface of the second battery module group.

2. The battery pack according to claim 1 , wherein the battery cells are stacked along the width direction in an upright state such that one surface of a cell body of the battery cell is perpendicular to a bottom of the pack frame.

3. The battery pack according to claim 1 or 2, wherein the battery cells are pouch-type battery cells.

4. The battery pack according to claim 1 , wherein the first cover member is positioned so as to correspond to the entire upper surface of the first battery module group.

5. The battery pack according to claim 1 , wherein the second cover member is positioned so as to correspond to the entire upper surface of the second battery module group.

6. The battery pack according to claim 1 , wherein the pack frame includes a partition portion located between the first battery module group and the second battery module group.

7. The battery pack according to claim 1 , further comprising a connecting member that connects adjacent battery modules together among the battery modules.

8. A device comprising a battery pack according to any one of claims 1 to 7.

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