Improved safety of battery packs

Abstract

The present invention relates to a battery pack, and the battery pack has an advantage that when heat is generated or thermal runaway occurs in one of a plurality of battery modules provided inside the battery pack, a thermal conductive pad is evaporated to form a separation space between the base plate and the battery module, thereby preventing the heat of the battery module from being transmitted to an adjacent battery module, thereby improving the safety of the battery pack against fire or explosion.

Description

[Technical field]

[0001] The present invention relates to a battery pack with improved safety in the event of thermal runaway.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0110500 dated September 1, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Currently, commercial secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. Among these, lithium secondary batteries are attracting attention due to 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.

[0004] Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as positive and negative active materials, respectively. The lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate, each coated with a positive electrode active material and a negative electrode active material, are disposed with a separator therebetween, and an exterior material, i.e., a battery case, that hermetically houses the electrode assembly together with an electrolyte.

[0005] Generally, 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.

[0006] In recent years, secondary batteries have been widely used for driving and energy storage not only in small devices such as portable electronic devices but also in medium-sized and large devices such as automobiles and energy storage systems (ESS). The secondary batteries are provided in a battery pack and installed in the medium-sized and large devices. In this case, in order to increase the capacity and output of the battery pack, the battery pack includes a number of secondary batteries which are electrically connected to each other. Here, a number of secondary batteries may be housed inside one module case to form one battery module, and a number of battery modules may be housed inside one pack case to form one battery pack.

[0007] Generally, when a secondary battery is used in an environment where the temperature is higher than the appropriate temperature, the performance of the secondary battery may be degraded, and in the worst case, there may be a risk of explosion or fire. In addition, when a battery pack is formed using a number of secondary batteries, the heat generated from the multiple secondary batteries is added together in a small space, and the temperature of the battery pack may rise more quickly and violently. In particular, battery packs for vehicles and battery packs for power storage devices, which are mainly used outdoors, are frequently exposed to direct sunlight and may be placed in severe high-temperature conditions such as in summer or in desert regions.

[0008] In addition, a battery pack is composed of a plurality of battery modules and a plurality of secondary batteries. When an abnormal condition occurs in some of the battery modules or secondary batteries constituting the battery pack, heat may be generated. Once heat is generated, the temperature of the battery continues to rise and exceeds a certain critical temperature, and the battery continuously goes into a thermal runaway state. When such thermal runaway occurs inside a battery module or battery pack in which a plurality of battery cells are stacked, it may induce explosion or fire of the battery cells. In this case, the flame spreads to other battery cells that are operating normally, causing a chain reaction of explosions of the plurality of battery cells, which may damage the device in which the battery module / pack is installed and may expose users to the risk of safety accidents. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Korean Patent Publication No. 10-2019-0018389 Summary of the Invention [Problem to be solved by the invention]

[0010] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a battery pack with improved safety by effectively controlling heat generation and thermal runaway conditions. [Means for solving the problem]

[0011] To solve the above-mentioned problems, In one embodiment, the present invention comprises: A battery pack housing a plurality of battery modules, a base plate including a module area in which the battery module is located; a sidewall extending vertically along an edge of the base plate so as to surround the module area and being coupled thereto; a partition wall coupled to the side wall to partition the base plate into a plurality of module regions; A pack case comprising: the partition wall includes a fastening portion protruding inwardly from a lower end thereof to be fastened to a battery module, A battery pack is provided, which includes a thermally conductive pad that changes phase to a gaseous state at high temperatures to form a separation space between the battery module located in the module region of the base plate and the base plate.

[0012] In this case, the fastening portion may be located at a height of 0.5 mm to 5.0 mm based on the lower end of the side wall.

[0013] Also, the fastening portion may be formed in a plurality of pieces spaced apart at a predetermined interval along the lower end of the partition wall.

[0014] The thermally conductive pad may contain a polymer that vaporizes or sublimes at 100 to 800°C.

[0015] The thermally conductive pad may have a structure in which a thermally conductive filler is dispersed in a matrix containing a polymer that vaporizes or sublimes at 100 to 800°C.

[0016] Here, the thermally conductive filler is aluminum, copper, zinc, magnesium, stainless steel, silver, alumina (Al 2 O 3 ), silicone (SiO 2 ), Aluminum Nitride (AlN 3 ), carbon nanotubes, silicon carbide (SiC), graphite, and activated carbon.

[0017] The thermally conductive filler may also be in the form of needle-like particles or fiber-like particles.

[0018] The thermally conductive filler may be contained in an amount of 1 to 30% by weight based on the total weight of the thermally conductive pad.

[0019] In addition, the thermally conductive pad may have an average thickness of 0.5 mm to 5.5 mm, and may have a thickness equal to or greater than the distance between the battery module and the base plate.

[0020] Further, the module area may include a central portion and an outer portion, and the thermal conduction pad may be located in the central portion. Effect of the Invention

[0021] The battery pack according to the present invention has an advantage in that when heat is generated or thermal runaway occurs in one of the multiple battery modules installed therein, a separation space is formed between the base plate and the battery module due to evaporation of the thermal conduction pad, thereby preventing the heat from the battery module from being transmitted to an adjacent battery module, thereby improving the safety of the battery pack against fire or explosion. [Brief description of the drawings]

[0022] [Figure 1] 1 is a perspective view showing a structure of a battery pack according to the present invention; [Diagram 2] 1A and 1B are a perspective view and a plan view showing a pack case according to the present invention. [Diagram 3] 1 is a cross-sectional view showing a structure of a battery pack according to the present invention to which a battery module is attached. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Since the present invention can be modified in various ways and can have various embodiments, specific embodiments are described in detail in the detailed description.

[0024] However, this is not intended to limit the invention to any particular embodiment, but is understood to include all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0025] In the present invention, the terms "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are understood as not precluding the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0026] In addition, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion in between. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion in between. In addition, in the present application, being "on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0027] The present invention will now be described in more detail.

[0028] <Battery pack> In one embodiment, the present invention comprises: A battery pack housing a plurality of battery modules, a base plate including a module area in which the battery module is located; a sidewall extending vertically along an edge of the base plate so as to surround the module area and being coupled thereto; a partition wall coupled to the side wall to partition the base plate into a plurality of module regions; A pack case comprising: the side walls and the partition wall each include a fastening portion protruding inwardly from a lower end thereof to be fastened to a battery module, A battery pack is provided, which includes a thermally conductive pad that changes phase to a gaseous state at high temperatures to form a separation space between the battery module located in the module region of the base plate and the base plate.

[0029] The battery pack according to the present invention includes a plurality of battery modules and a pack case accommodating the battery modules. The pack case includes a fastening part for fixing the battery modules to an inner side of a lower end of a partition wall such that the battery modules are disposed at a certain height apart from a base plate, and a thermally conductive pad for changing into a gaseous state at a high temperature to form a separation space between the base plate and the battery modules fixed to the fastening part. The fastening part and the thermally conductive pad may form a separation space between the base plate and the battery modules due to vaporization of the thermally conductive pad when heat is generated or thermal runaway occurs in any one of the battery modules. The thus-formed separation space may prevent heat from the battery module from being transmitted to an adjacent battery module, thereby preventing ignition and / or explosion of the battery pack.

[0030] 1 to 3 are a perspective view, a plan view and a cross-sectional view illustrating the structure of a battery pack 100 according to the present invention. A more detailed description will be given below with reference to FIGS.

[0031] The battery pack 100 of the present invention includes a battery module 110 and a pack case in which the battery module 110 is housed.

[0032] Here, the battery module 110 referred to in the present invention may include a module case to house such secondary batteries. That is, the module case may be said to constitute the exterior or outer surface of the battery module 110, and one or more secondary batteries may be housed inside such a module case. In particular, when a number of secondary batteries are provided in the battery module 110, the secondary batteries may be stacked in a number in at least one direction.

[0033] At this time, when the secondary battery included in the battery module 110 is a pouch-type secondary battery, a number of stacking cartridges may be further included in the battery module 110. The stacking cartridges may be configured to be stackable with each other to facilitate stacking of the pouch-type secondary batteries and improve fixation. Also, the stacking cartridges may be configured in a form in which a frame is provided on the edge of the pouch-type secondary batteries.

[0034] In addition, the secondary battery included in the battery module 110 is not limited to the above-mentioned pouch-type battery cell, and may be, for example, a cylindrical battery cell. That is, the battery cell may be any of various known battery cells.

[0035] The module case may be formed in a substantially rectangular parallelepiped shape as shown in Fig. 1. In this case, the module case may have an upper portion, a lower portion, a left side portion, a right side portion, a front end portion, and a rear end portion.

[0036] Also, a module terminal may be provided at least at one of the front end and the rear end of the module case. The module case may be configured in a form including a body part having an open front end and / or a hollow space therein for accommodating a secondary battery, a front end cover covering the front end and / or a rear end cover covering the rear end. Alternatively, the module case may be configured in a form including a body part having an open top, being box-shaped, for accommodating a secondary battery in its internal space, and an upper cover for sealing the upper open end. The module case may be configured in various other forms.

[0037] The module case may be configured in a sealed form to protect the secondary batteries housed therein from external physical and chemical factors, etc. For example, the module case may be configured in a form in which the top, bottom, left, right, front and rear are all sealed so that the upper, lower, left and right sides, front and rear of the secondary batteries housed therein are not exposed to the outside. With this configuration, the module case may be a component that forms the outside of one battery module and may be a boundary that separates the outside and inside of the battery module.

[0038] The module case may include an electrically insulating material such as plastic to ensure electrical insulation between the outside and the inside of the battery module 110. However, the module case may also be made of various other materials or may further include other materials.

[0039] The multiple secondary batteries included in the battery module 110 may be electrically connected in series and / or parallel to each other. In addition, module terminals (+ terminal, - terminal) may be provided on the outside of the module case of the battery module 110, for example, on the upper front surface of the module case, and may be electrically connected to the secondary batteries inside the battery module 110. The module terminals may be electrically connected to each other via a power cable or a bus bar (not shown) for connecting the battery modules 110 to each other or to a device outside the battery module 110. A detailed configuration of the battery module 110 for this purpose may be a commonly known configuration, and will not be described in detail here.

[0040] A plurality of battery modules 110 may be provided in a battery pack. Also, the plurality of battery modules 110 may be arranged in a left-right direction with their sides facing each other. For example, the battery pack 100 may include at least two battery modules 110. In this case, the two battery modules 110 may be arranged in a left-right direction with their right and left sides facing each other.

[0041] Furthermore, the battery pack 100 may include a pack case including the above-described battery module 110. If necessary, the battery pack 100 may further include a pack case cover (not shown) coupled to the pack case to cover an upper portion of the battery module 110 at an upper portion of the pack case.

[0042] Here, the pack case may include a base plate 120 disposed under the battery module 110 and including a module area in which the battery module 110 is located. The base plate 120 may have a plate shape extending in a horizontal direction. Here, the horizontal direction refers to the surface direction of a flat ground. The base plate 120 may be made of a metal material having excellent mechanical rigidity.

[0043] In addition, a plurality of battery modules 110 may be positioned on the upper portion of the base plate 120. To this end, the base plate 120 may include a module area in which the battery modules 110 are positioned, and side walls 130 extending vertically along edges of the base plate to surround the module area may be coupled to each other to form a space for accommodating the battery modules 110.

[0044] At this time, the base plate 120 may function not only to provide a space for accommodating the battery module 110 thereunder, but also to function as a heat sink for dissipating heat generated in the battery module 110 to the outside. To this end, the base plate 120 may be provided with a cooling means (not shown) on a surface other than the surface on which the battery module 110 is accommodated, the cooling means being provided so that a coolant such as cooling water or air can flow in contact therewith. In addition, the side wall 130 may be coupled in a manner commonly applied in the art, for example, by friction stir welding.

[0045] In addition, the pack case includes a partition wall 140 that divides the internal space into a plurality of battery module regions so that a plurality of battery modules 110 can be mounted in an accommodating space defined by the side walls 130. At this time, the partition wall 140 may have both ends coupled to be perpendicular to two opposing side walls 130, as shown in FIG 1, and a lower end is configured to be coupled to an upper surface of the base plate 120.

[0046] In addition, the partition wall 140 includes a fastening portion 150 for fastening the battery module 110 at an inner lower end thereof so that the battery module 110 is disposed at a position spaced apart from the base plate 120 by a certain height.

[0047] The fastening part 150 is located at the inner lower part of the partition wall 140 and fastened to the lower surface of the battery module 110 to support the battery module 110. For this purpose, the fastening part 150 may be applied without any particular limitation as long as it has a shape capable of supporting the battery module 110 from the lower part. However, preferably, as shown in FIG. 2, the fastening part 150 may include a surface facing the lower surface of the battery module 110, and may include a fastening hole 151 penetrating the surface facing the lower surface of the battery module 110 so that a fastening member such as a bolt (not shown) having a thread structure can be fixed when the surface contacts the lower surface of the battery module 110.

[0048] At this time, the fastening part 150 may be disposed such that the battery module 110 supported on the upper surface of the fastening part is spaced apart from the base plate 120 by a predetermined distance. Specifically, the fastening part 150 may be disposed at a height of 0.5 mm to 5.0 mm based on the upper surface of the base plate 120, and more specifically, at a height of 0.5 mm to 3.0 mm, 0.5 mm to 1.5 mm, or 0.8 mm to 1.2 mm. The present invention adjusts the position of the fastening part 150 to satisfy the above height based on the upper surface of the base plate 120, thereby preventing a decrease in efficiency of dissipating internal heat during normal operation of the battery pack 100 due to an excessive distance. In addition, by adjusting the position of the fastening part 150 as described above, it is possible to prevent heat from being generated in any one of the plurality of battery modules 110 or heat from being rapidly transferred to the adjacent battery module 110 via the base plate 120, which functions as a heat sink, due to a narrow distance during thermal runaway.

[0049] In addition, the fastening portion 150 may be located at the inner lower portion of the partition wall 140 and may be arranged at a predetermined interval so as to be firmly fastened along the lower edge of the battery module 110 .

[0050] As an example, the fastening parts 150 may be disposed at both lower ends of the inner surface of the partition wall 140 in which the battery module 110 is accommodated, as shown in FIG.

[0051] As another example, the fastening parts 150 may be disposed at both lower ends and a central lower part of the inner surface of the partition wall 140 in which the battery module 110 is accommodated.

[0052] The pack case includes a thermally conductive pad 160 in a space formed between the battery module 110 and the base plate 120 by the fastening part 150. The thermally conductive pad 160 transfers heat generated in the battery module 110 during normal operation of the battery pack 100 so that the heat can be dissipated through the base plate 120. In addition, the thermally conductive pad 160 is vaporized or sublimated during abnormal operation of the battery module 110, for example, during heat generation and / or thermal runaway of the battery module 110 in contact with the thermally conductive pad 160, and serves to form a space between the battery module 110 and the base plate 120.

[0053] For this, the thermal conduction pad 160 may include a polymer that vaporizes or sublimes at 100 to 800° C. so as to form an isolation space when the battery module 110 is not operating normally. More specifically, the polymer included in the thermal conduction pad 160 may include acrylic resin, epoxy resin, polystyrene resin, silicone resin, polyester resin, polyolefin resin, etc., and may be vaporized or sublimated at 100 to 600° C., 100 to 400° C., 100 to 300° C., or 150 to 300° C. by using an additive to these resins or by physical and chemical modification. By forming the thermal conduction pad from a polymer that vaporizes or sublimes in the above range, the present invention can realize a cooling effect due to the heat of vaporization / heat of sublimation of the thermal conduction pad when the battery module 110 generates heat and / or experiences thermal runaway, compared to a conventional thermal conduction pad formed from a polymer that simply melts. In addition, the thermal conduction pad can separate the battery module 110 generating heat from the base plate 120 before the battery pack 100 ignites and / or explodes, thereby preventing heat transmission to modules adjacent to the battery module 110 generating heat and / or experiencing thermal runaway.

[0054] In addition, the thermal conduction pad 160 may have a high thermal conductivity in a matrix (hereinafter referred to as a "polymer matrix") containing a polymer that vaporizes or sublimes at 100 to 800°C, and may have a structure in which a thermally conductive filler is dispersed in a matrix containing a polymer that vaporizes or sublimes at 100 to 800°C to achieve higher thermal conductivity.

[0055] In this case, the thermally conductive filler may be applied without any particular limitation as long as it is applied to realize a thermal conductive effect in a battery, a battery module, or a battery pack in the art. Specifically, aluminum, copper, zinc, magnesium, stainless steel, silver, alumina (Al 2 O 3 ), silicone (SiO 2 ), Aluminum Nitride (AlN 3 ), silicon carbide (SiC), carbon nanotubes, graphite, and activated carbon.

[0056] In addition, the thermally conductive filler may be included in an amount of 1 to 30 wt % based on the total weight of the thermally conductive pad in order to prevent contact between the battery module 110 and the base plate 120 after evaporation or sublimation of the polymer matrix. More specifically, the thermally conductive filler may be included in an amount of 1 to 20 wt %, 1 to 10 wt %, 10 to 30 wt %, 15 to 30 wt %, or 10 to 20 wt % based on the total weight of the thermally conductive pad.

[0057] In addition, the thermally conductive filler may be in the form of needle-like particles or fiber-like particles in order to realize high thermal conductivity of the thermally conductive pad even if the thermally conductive filler is contained in a small amount. In this case, the thermally conductive filler has an advantage that it can realize high thermal conductivity because it can form a thermally conductive network between fillers inside the polymer matrix even if it is dispersed in a small amount.

[0058] In this case, the average size of the thermally conductive filler may be 1,000 μm or less, specifically, 900 μm or less, 750 μm or less, 500 μm or less, 300 μm or less, 100 μm or less, 1 to 500 μm, 10 to 500 μm, 50 to 500 μm, 100 to 500 μm, 200 to 400 μm, or 50 to 300 μm. Here, the "average size" may mean the average value of the "major axis length" (the longest length passing through the particle center) and the "minor axis length" (the shortest length passing through the particle center) in the thermally conductive filler. By adjusting the average size of the thermally conductive filler to the above range, the present invention can realize high conductivity of the thermally conductive pad 160 while preventing contact between the battery module 110 and the base plate 120 after vaporization or sublimation of the polymer matrix.

[0059] Meanwhile, the thermal conduction pad 160 may have an average thickness of 0.5 mm to 5.5 mm, and may have a thickness equal to or greater than the distance between the battery module 110 and the base plate 120. The thermal conduction pad 160 may have an average thickness equal to or greater than the distance between the battery module 110 and the base plate 120, and thus may easily release heat generated in the battery module 110 to the base plate 120, i.e., from the upper surface to the lower surface of the thermal conduction pad 160, during normal operation of the battery pack 100. Furthermore, since the thermal conduction pad 160 has the above-mentioned thickness condition, it may act as a buffer when an external force is applied to the battery pack 100, particularly when an external force is applied from above, and thus has an advantage of being safer.

[0060] Furthermore, the thermal conduction pad 160 may be disposed over the entire module area of ​​the base plate 120, or may be disposed partially in some cases. The thermal conduction pad 160 may be disposed over the module area of ​​the base plate 120, and may be formed partially in a certain area, specifically, 60 to 99% of the entire area. Thus, the thermal conduction pad 160 may increase the surface area of ​​the surface in contact with the battery module 110, and thus the thermal conductivity may be further improved.

[0061] As one example, the module region may include a central portion and an outer portion, and the thermal conduction pad may be located in the central portion, which has an advantage that the thermal conduction pad may more effectively dissipate internal heat that is frequently and highly generated during normal operation of the battery pack.

[0062] The battery pack according to the present invention has the above-mentioned configuration, and when heat is generated in one of the plurality of battery modules provided therein or when thermal runaway occurs, a separation space is formed between the base plate and the battery module due to evaporation of the thermal conduction pad, thereby preventing the heat from the battery module from propagating to an adjacent battery module, thereby improving the safety of the battery pack against fire or explosion.

[0063] The present invention will now be described in more detail with reference to examples and experimental examples.

[0064] However, the following examples and experimental examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

[0065] <Comparative Example> A battery pack was prepared in which eight battery modules, each containing ten pouch cells, were inserted horizontally and vertically, two by two, into a pack case. The pack case had the same structure as in Figure 1, but without the "fastening part" and "thermal conduction pad".

[0066] <Example> A battery pack was prepared in which eight battery modules, each including ten pouch cells, were inserted into a pack case, two by two, horizontally and two by two, vertically. A pack case having the same structure as that shown in FIG. 1 was used, and a thermally conductive pad having an average thickness equivalent to the distance between the battery module and the base plate (about 1.8±0.2 mm) was applied. The thermally conductive pad was made of a polymer matrix having a vaporization temperature as shown in Table 1 below, and when a thermally conductive filler was included, the content of the thermally conductive filler was adjusted to about 15 wt % based on the total weight of the thermally conductive pad. The type and arrangement of the thermally conductive filler applied to the thermally conductive pad are as shown in Table 1.

[0067] [Table 1]

[0068] <Experimental Example> In order to evaluate the safety of the battery pack according to the present invention, a thermal runaway was induced in one of the battery modules installed in the battery pack, and the time it took for the battery module in which the thermal runaway was induced and the adjacent battery module to ignite was measured.

[0069] Specifically, the battery packs manufactured in the examples and comparative examples were all charged to SOC 100%. Then, a heating pad was attached to the top of any one of the four battery modules arranged in the center of the eight battery modules housed in the pack case, and the heating pad was operated with 300 W of power to induce thermal runaway in the battery module arranged below the heating pad.

[0070] At this time, the inside of the battery pack was observed for 10 minutes from the time the heating pad was activated, and i) the time it took for the battery module placed under the heating pad to ignite was measured, and ii) whether or not the battery module placed adjacent to the battery module with the heating pad attached had ignited was confirmed. The results are shown in Table 2 below.

[0071] [Table 2]

[0072] As shown in Table 2 above, it can be seen that the battery pack according to the present invention has improved high temperature safety.

[0073] Specifically, it was confirmed that in the battery pack of the embodiment, when the battery module is exposed to high temperatures, the thermally conductive pad evaporates to form a separation space between the battery module and the base plate, which functions as a heat sink, thereby preventing heat transfer to adjacent battery modules and suppressing ignition of the battery module.

[0074] Meanwhile, in a comparative example battery pack in which a battery module exposed to high temperatures was placed adjacent to a base plate, it was found that the adjacent battery module caught fire.

[0075] These results indicate that the battery pack according to the present invention can prevent the heat of a battery module from being transmitted to an adjacent battery module by forming a separation space between the base plate and the battery module through evaporation of the thermal conduction pad when the battery module generates high temperature or experiences thermal runaway.

[0076] Although the present invention has been described above with reference to preferred embodiments, it will be understood that a person skilled in the art or having ordinary knowledge in the art may make various modifications and changes to the present invention without departing from the spirit and technical scope of the present invention as described in the claims below.

[0077] Therefore, the technical scope of the present invention is not limited to the contents described in the Summary of the Invention of the specification, but is defined by the claims. [Explanation of symbols]

[0078] 100: Battery pack of the present invention 110: Battery module 120: Base plate 130: Side wall 140: Bulkhead 150: Fastening part 151: Concluding hole 160:Heat conductive pad

Claims

1. A battery pack housing a plurality of battery modules, a base plate including a module area in which the battery module is located; a sidewall extending vertically along an edge of the base plate to surround the module area; a partition wall coupled to the side wall to partition the base plate into a plurality of module regions; A pack case comprising: the partition wall includes a fastening portion protruding inwardly from a lower end thereof and fastened to the battery module, The battery pack further includes a thermal conductive pad, which is disposed between the battery module and the base plate and changes into a gaseous state at a high temperature to form a space between the battery module and the base plate.

2. The battery pack of claim 1, wherein the fastening portion is located at a height of 0.5 mm to 5.0 mm from a lower end of the side wall.

3. The battery pack of claim 1 , wherein the fastening portion is formed in a plurality of portions spaced apart at predetermined intervals along a lower end of the partition wall.

4. The battery pack of claim 1 , wherein the thermal conductive pad includes a polymer that vaporizes or sublimes at 100 to 800° C.

5. The battery pack according to claim 1 , wherein the thermally conductive pad has a structure in which a thermally conductive filler is dispersed in a matrix containing a polymer that vaporizes or sublimes at 100 to 800° C.

6. The thermally conductive filler may be aluminum, copper, zinc, magnesium, stainless steel, silver, alumina (Al ２ O ３ ), silicone (SiO ２ ), aluminum nitride (AlN ３ 6. The battery pack of claim 5, comprising one or more of the following: carbon nanotubes, silicon carbide (SiC), graphite, and activated carbon.

7. 6. The battery pack according to claim 5, wherein the thermally conductive filler is an acicular particle or a fibrous particle.

8. The battery pack according to claim 5 , wherein the thermally conductive filler is contained in an amount of 1 to 30% by weight based on the total weight of the thermally conductive pad.

9. 2. The battery pack according to claim 1, wherein the thermal conduction pad has an average thickness of 0.5 mm to 5.5 mm and is equal to or greater than a distance between the battery module and the base plate.

10. The battery pack according to claim 1 , wherein the module area includes a central portion and an outer portion, and the thermal conduction pad is located in the central portion.

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