Battery pack and vehicle including same

Abstract

A battery pack according to the present invention comprises: a pack case that has, on the inside, an accommodation space for accommodating a plurality of battery cells, and has an opening part on one side; a pack lid that covers the opening part; a partition frame that is coupled to the pack case to partition the accommodation space; and bolt members, at least a portion of each of which passes through the pack lid, and is coupled to the partition frame and has a first threaded part disposed at the end close to the partition frame, wherein the first threaded part includes a high-temperature-sensitive material that changes in material properties in certain high-temperature environments to weaken the coupling strength between a bolt member and the partition frame.

Description

Battery pack and vehicle including same

[0001] The present invention relates to a battery pack, and more particularly, to a battery pack in which a pack lead swells in response to increased internal pressure when a thermal event occurs in the battery pack, thereby reducing the internal pressure of the battery pack or reducing the rate of increase in internal pressure and delaying heat transfer.

[0002] This application claims priority to Korean Patent Application No. 10-2024-0047651, filed April 8, 2024, the entire disclosure of which is incorporated herein by reference.

[0003] A semi-permanent battery that converts electrical energy into chemical energy and can be repeatedly charged and discharged is called a secondary battery, to distinguish it from a primary battery that cannot be reused after a single use.

[0004] In particular, lithium-ion secondary batteries have been actively utilized as electric vehicle batteries recently due to their high energy storage density, lightweight and miniaturized design, excellent safety, low discharge rate, and long lifespan. Lithium-ion secondary batteries are generally classified into cylindrical, prismatic, and pouch types depending on their manufacturing form. Their applications are diverse, encompassing not only electric vehicle batteries but also energy storage system (ESS) batteries and other electrical devices.

[0005] Currently, the operating voltage of a single lithium-ion secondary battery cell is approximately 2.5 V to 4.5 V. Therefore, in order to apply a secondary battery as an energy source for an electric vehicle, a battery module is formed by connecting multiple lithium-ion secondary battery cells in series and / or parallel, and a battery pack is formed by connecting the battery modules in series and / or parallel.

[0006] Meanwhile, secondary batteries undergo chemical reactions during charging and discharging, which can lead to performance degradation if used in environments above their optimal temperature. Furthermore, if thermal control fails to maintain optimal temperatures, there's a constant risk of unexpected fire or explosion. Furthermore, battery packs, which are a collection of secondary batteries, are structured to house these batteries as tightly as possible within the pack case, making them vulnerable to thermal events.

[0007] Accordingly, if a thermal event such as overheating or thermal runaway occurs in a specific battery module, the internal pressure within the battery pack increases due to venting gases and flames generated from the battery module where the event occurred, accelerating the accumulation of thermal energy and easily causing thermal propagation to adjacent battery modules. This can lead to a problem of cascading thermal runaway of battery modules and explosion of the entire battery pack.

[0008] Accordingly, it is necessary to improve the structure of the battery pack to lower the internal pressure increased inside the battery pack due to venting gas and flames generated from thermal events in the first ignited battery module, and to effectively disperse the thermal energy, thereby delaying the thermal transfer phenomenon that propagates chain reaction to neighboring battery modules.

[0009] The present invention was created in consideration of the above-described problems, and has as its primary purpose the provision of a battery pack having further enhanced structural rigidity and an automobile including the same.

[0010] Another object of the present invention is to provide a battery pack having a reinforced fixing force between a pack lead and a partition frame and a vehicle including the same.

[0011] In addition, another object of the present invention is to provide a battery pack and a vehicle including the same, which can effectively prevent a heat transfer phenomenon by weakening the bonding force between a bolt member and a partition frame when a thermal event occurs inside the battery pack.

[0012] In addition, another object of the present invention is to provide a battery pack and a vehicle including the same, which can effectively prevent a heat transfer phenomenon by causing the pack lead to swell when a thermal event occurs inside the battery pack.

[0013] In addition, another object of the present invention is to provide a battery pack and a vehicle including the same, which improve the assemblability and productivity of the pack case.

[0014] Another purpose is to provide a battery pack with improved structural stability and a vehicle including the same.

[0015] In addition, another object of the present invention is to provide a battery pack and a vehicle including the same, which can effectively prevent heat transfer by preventing the inflow of oxygen and the emission of flame.

[0016] The technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0017] A battery pack according to the present invention comprises: a pack case having a space for accommodating a plurality of battery cells therein and an opening formed at one side thereof; a pack lid covering the opening; a partition frame coupled to the pack case to partition the space; and a bolt member having at least a portion penetrating the pack lid, coupled to the partition frame, and having a first screw portion disposed at an end close to the partition frame, wherein the first screw portion includes a high-temperature-vulnerable material whose properties change in a predetermined high-temperature environment to weaken a bonding force between the bolt member and the partition frame.

[0018] The above pack lead may be configured to swell when the internal pressure of the receiving space increases.

[0019] The above high temperature vulnerable material can melt in a certain high temperature environment and function as a lubricant.

[0020] The above high temperature vulnerable material may be composed of a resin material.

[0021] The above first screw portion may have the high temperature vulnerable material coated on its outer surface.

[0022] The above partition frame is formed with a fastening groove having a female thread to fasten the bolt member, and the length of the first screw portion can correspond to the depth of the fastening groove.

[0023] The above bolt member may further include a second screw portion connected to the first screw portion on a side far from the partition frame.

[0024] The above second screw portion may be made of a metal material.

[0025] The outer surface of the above second screw portion may be heat-treated and subjected to a locking coating.

[0026] The second screw portion may be formed to have a core portion extending toward the partition frame, and the first screw portion may be formed such that the high-temperature vulnerable material surrounds the core portion.

[0027] It may further include an intermediate member disposed between the pack lead and the partition frame and through which the bolt member passes.

[0028] The above intermediate member can be in close contact with the pack lead and the partition frame.

[0029] The above intermediate member may be configured as a joint nut having a female thread formed on the inside and at least a portion of which is joined to the pack lead.

[0030] A sealing member may be further placed between the pack lead and the bolt member to seal them.

[0031] A vehicle according to the present invention comprises at least one battery pack according to the present invention.

[0032] According to the present invention, a battery pack and a vehicle including the same can be provided with structural rigidity further enhanced by a bolt member and a partition frame.

[0033] In addition, according to the present invention, a battery pack and a vehicle including the same can be provided in which the fixing force between the pack lead and the partition frame is reinforced by a bolt member.

[0034] In addition, according to the present invention, a battery pack and a vehicle including the same can be provided that can effectively prevent a heat transfer phenomenon by weakening the bonding force between a bolt member and a partition frame when a thermal event occurs inside the battery pack.

[0035] In addition, according to the present invention, a battery pack and a vehicle including the same can be provided, which can effectively prevent a heat transfer phenomenon by causing a pack lead to swell when a thermal event occurs inside the battery pack.

[0036] In addition, according to the present invention, a battery pack and a vehicle including the same can be provided in which the assembling ability and productivity of the pack case are improved by a bolt member.

[0037] In addition, according to the present invention, a battery pack and a vehicle including the same can be provided, in which assembly and productivity are further improved and structural stability is improved by the intermediate member.

[0038] In addition, according to the present invention, a battery pack and a vehicle including the same can be provided that can effectively prevent heat transfer by preventing the inflow of oxygen and the emission of flame by an intermediate member or a sealing member.

[0039] The effects of the present invention are not limited to the effects described above, and effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention pertains from this specification and the attached drawings.

[0040] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0041] FIG. 1 is a perspective view showing the overall appearance of a battery pack according to one embodiment of the present invention.

[0042] Figure 2 is a perspective view showing the battery pack of Figure 1 in an exploded state.

[0043] FIG. 3 is a side cross-sectional view illustrating a bolt member coupled to a partition frame in a battery pack according to one embodiment of the present invention.

[0044] FIG. 4 is a side cross-sectional view showing a battery pack according to one embodiment of the present invention in which a bolt member is disassembled from a partition frame.

[0045] Figure 5 is a cross-sectional view taken along line AA' of Figure 1.

[0046] Figure 6 is a cross-sectional side view showing the pack lead inflated in Figure 5.

[0047] FIG. 7 is a perspective view illustrating a bolt member of a battery pack according to another embodiment of the present invention.

[0048] FIG. 8 is a side cross-sectional view illustrating an intermediate member further arranged in a bolt member and a partition frame in a battery pack according to one embodiment of the present invention.

[0049] FIG. 9 is a side cross-sectional view illustrating a sealing member further arranged on a bolt member and a partition frame in a battery pack according to one embodiment of the present invention.

[0050] FIG. 10 is a drawing illustrating a vehicle according to one embodiment of the present invention.

[0051] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that conforms to the technical spirit of the present invention.

[0052] Therefore, it should be understood that the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0053] FIG. 1 is a perspective view showing the overall appearance of a battery pack according to one embodiment of the present invention, FIG. 2 is an exploded perspective view of the battery pack of FIG. 1, FIG. 3 is a side cross-sectional view showing a bolt member coupled to a partition frame in a battery pack according to one embodiment of the present invention, and FIG. 4 is a side cross-sectional view showing a bolt member exploded from a partition frame in a battery pack according to one embodiment of the present invention.

[0054] Hereinafter, a battery pack (10) according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4. The battery pack (10) according to an embodiment of the present invention includes a pack case (200), a pack lid (300), a partition frame (210), and a bolt member (400).

[0055] A receiving space (S) and an opening (O) are formed in the pack case (200). A plurality of battery cells (100) are received in the receiving space (S). The battery cell (100) may be understood as a secondary battery including an electrode assembly, an electrolyte, and a pouch case that receives the electrode assembly. In the present embodiment, a pouch-type battery cell (100) having a high energy density and easy stacking is used, but the present invention is not limited thereto, and it is obvious that a cylindrical or square secondary battery may be applied as the battery cell (100).

[0056] A pouch-type battery cell (100) may include a pair of electrode leads that are connected to an electrode assembly and extend outward from the pouch case and function as electrode terminals. Such a battery cell (100) may further be equipped with electrical components such as a busbar, a busbar frame, and a module connector adjacent to the pair of electrode leads.

[0057] In the receiving space (S) of the pack case (200), the battery cells (100) may be received as battery modules in module units. In this case, the battery module may include a module case. At least one battery cell (100) may be received in the module case. The module case may be made of a metal material with high rigidity and durability or a plastic material such as ABS resin to physically or chemically protect the received battery cells (100). A terminal of the battery module may be provided on a side of the module case. The terminal may be either a positive or negative terminal, and may be placed on both sides or one side of the module case.

[0058] The receiving space (S) is formed on the inside of the pack case (200). The pack case (200) includes a bottom portion (201) and a side wall portion (202) surrounding the bottom portion (201), and the bottom portion (201) and the side wall portion (202) form a receiving space (S) on the inside.

[0059] A partition frame (210) is coupled to the pack case (200). The partition frame (210) is coupled to the pack case (200) to partition a receiving space (S). The partition frame (210) may be arranged across the receiving space (S). The partition frame (210) may include a horizontal frame (211) and a vertical frame (212). The horizontal frame (211) may be formed to extend in the Y direction and partition the receiving space (S) along the X direction. The vertical frame (212) may be formed to extend in the X direction and partition the receiving space (S) along the Y direction. In the embodiment of the present invention, the pack case (200) is illustrated as having two horizontal frames (211) and one vertical frame (212), but the number of horizontal frames (211) and vertical frames (212) or the number of battery cells (100) accommodated are not limited thereto and may vary. The horizontal frame (211) or the vertical frame (212) may also be referred to as a cross beam or a center beam.

[0060] In order to withstand the load of the battery cell (100) and protect the battery cell (100) from external force, the pack case (200) and the partition frame (210) may be made of a metal material such as steel or aluminum.

[0061] An opening (O) is formed on one side of the pack case (200). As in the illustrated example, the opening (O) may be formed on the upper side of the pack case (200). A pack lid (300) is arranged in the opening (O). The pack lid (300) is arranged to cover the opening (O). The pack lid (300) may cover the receiving space (S) of the pack case (200) to block the receiving space (S) from the outside. The pack lid (300) may be provided in a shape corresponding to the shape of the opening (O). For example, when the opening (O) has a rectangular shape, the pack lid (300) may also be provided in a rectangular shape. The pack lid (300) may be provided in a shape slightly larger than the opening (O) so as to cover the edge of the opening (O). The pack lid (300) may be provided in a thin plate shape. For example, the pack lid (300) may be provided in the form of a thin rectangular plate. The pack lid (300) may be made of a metal material, such as aluminum, identical or similar to the pack case (200) and the partition frame (210). As another example, the pack lid (300) may be provided of a material capable of elastic deformation or plastic deformation by an external force.

[0062] The bolt member (400) is configured such that at least a portion thereof penetrates the pack lead (300) and is coupled to the partition frame (210). A plurality of bolt members (400) may be provided. The direction in which the bolt members (400) penetrate may be formed parallel to the Z direction. The bolt members (400) may be fastened to and coupled to the partition frame (210).

[0063] The bolt member (400) may be provided in a form in which at least a portion thereof is extended toward one end, and at least a portion of the one end thereof may penetrate the pack lead (300). The bolt member (400) includes a screw portion (410) having a male thread formed therein, and may further include a head portion (420) having a head formed therein, and the screw portion (410) may penetrate the pack lead (300). The screw portion (410) may have male threads continuously formed at a predetermined pitch from one end to the other end. The bolt member (400) may be made of a metal material such as steel / SUS. Such a material is resistant to high temperatures, has excellent rigidity, and can secure a high fastening force.

[0064] The bolt member (400) includes a first screw portion (411). The first screw portion (411) is arranged at an end of the bolt member (400) close to the partition frame (210). Referring to the drawing, the lower end of the bolt member (400) may be the first screw portion (411). The first screw portion (411) may constitute a part of the screw portion (410). That is, a portion of the pitch section on the lower end side of the screw portion (410) may be referred to as the first screw portion (411). The first screw portion (411) may be a part of the screw portion (410) that is arranged close to the partition frame (210) and far from the pack lead (300). The first screw portion (411) may be understood as a part that includes a region of the bolt member (400) that is fastened to the partition frame (210).

[0065] A through hole (310) through which a bolt member (400) passes may be formed in the pack lid (300). The through holes (310) may be formed in a corresponding number at positions corresponding to the bolt member (400). Since the through hole (310) does not have a female thread, the screw portion (410) of the bolt member (400) may simply pass through the through hole (310), and the head portion (420) may be positioned on the upper side of the pack lid (300) without passing through the through hole (310).

[0066] A fastening groove (220) may be formed in the partition frame (210). A bolt member (400) may be fastened and coupled to the fastening groove (220). The fastening groove (220) may be formed by forming and recessing a female thread corresponding to the male thread of the screw portion (410) of the bolt member (400). The fastening groove (220) may be formed by tapping the partition frame (210). By means of the fastening groove (220), the bolt member (400) may be bolted and coupled to the partition frame (210). At this time, the first screw portion (411) may be understood as a portion including an area of ​​the bolt member (400) that is fastened to the fastening groove (220).

[0067] The fastening grooves (220) may be arranged in corresponding numbers at positions corresponding to the bolt members (400). A plurality of fastening grooves (220) may be arranged spaced apart from each other. The spacing between a pair of adjacent fastening grooves (220) may be formed differently from the spacing between the fastening grooves (220) of another pair of adjacent fastening grooves. The fastening grooves (220) may be arranged only in a part of the partition frame (210) or may be arranged in the entire area of ​​the partition frame (210).

[0068] The bolt member (400) may further include a second screw portion (412). The second screw portion (412) is a portion connected to the first screw portion (411) on the side far from the partition frame (210). The second screw portion (412) may be a portion between the first screw portion (411) and the head portion (420). The second screw portion (412) may form the screw portion (410) together with the first screw portion (411). The second screw portion (412) may be a portion of the screw portion (410) that is positioned close to the pack lead (300) and far from the partition frame (210). That is, a portion of the pitch section on the upper side of the screw portion (410) may be referred to as the second screw portion (412). The second screw portion (412) can be understood as a portion that includes an area in the bolt member (400) that is not fastened to the partition frame (210) or the fastening groove (220). When the bolt member (400) is completely fastened to the partition frame (210), the second screw portion (412) is arranged in an area corresponding to the pack lead (300), and when an intermediate member (500) is further arranged between the pack lead (300) and the partition frame (210) as described below, the second screw portion (412) can be understood as a portion that is also arranged in an area corresponding to the intermediate member (500).

[0069] The first screw portion (411) includes a high-temperature-vulnerable material whose properties change in a predetermined high-temperature environment, thereby weakening the bonding force between the bolt member (400) and the partition frame (210). Here, the predetermined high-temperature environment may be, for example, a temperature environment of 100 to 250 degrees Celsius, and preferably, a temperature environment of 150 to 200 degrees Celsius. When a thermal event occurs inside the battery pack (10), the predetermined high-temperature environment may be generated due to the discharge of venting gas and solid discharge, and at this time, the internal pressure of the battery pack (10) may increase. Here, the change in properties may be understood as, for example, a change in properties that melt at high temperatures.

[0070] When a high temperature and high pressure thermal event occurs inside the battery pack (10), the physical properties of the portion of the first screw portion (411) that includes a high temperature vulnerable material may change, thereby weakening the fixing force between the pack lead (300) and the partition frame (210), thereby securing space for the pack lead (300) to swell. Through this, the heat transfer phenomenon can be prevented.

[0071] Conventionally, when manufacturing a battery pack (10), bolts and nuts made of steel / SUS material were applied to the fastening portion between the pack case (200) and the pack lid (300). However, in such a battery pack (10), even when a thermal event occurred, the pack lid (300) did not swell due to the strong bolting. In other words, since the pack lid (300) of the conventional battery pack (10) was fixed so as not to swell due to the strong bolting, it was vulnerable to the heat transfer phenomenon.

[0072] In contrast, in the battery pack (10) according to one embodiment of the present invention, since the bolt member (400) including the first screw portion (411) is coupled to the partition frame (210), the bolting is strongly fastened to meet vibration and impact test conditions in normal conditions such as normal conditions, thereby ensuring structural stability. However, when a thermal event such as a battery cell (100) ignition occurs, the bonding force between the bolt member (400) and the partition frame (210) is weakened, thereby allowing the pack lid (300) to swell, thereby preventing a heat transfer phenomenon. Here, the weakening of the bonding force between the bolt member (400) and the partition frame (210) means a state in which the bolt member (400) and the partition frame (210) are easily separated from each other. This effect will be discussed in more detail in the description below with reference to FIGS. 5 and 6.

[0073] The high-temperature vulnerable material included in the first screw portion (411) can melt in a predetermined high-temperature environment and function as a lubricant. Specifically, the first screw portion (411) normally maintains a solid state, but in a predetermined high-temperature environment, its physical properties change and it can melt and become a liquid state, and the high-temperature vulnerable material in this state can perform a lubricant function by reducing the frictional force formed between the bolt member (400) and the fastening groove (220). Accordingly, in a predetermined high-temperature environment, the bolt member (400) is placed in a state where it can be easily separated from the fastening groove (220) of the partition frame (210).

[0074] The high-temperature-vulnerable material included in the first screw portion (411) may be a resin material. The high-temperature-vulnerable material may be a moldable material. The melting point of the high-temperature-vulnerable material may be formed lower than the melting point of the material constituting the partition frame (210). The resin absorbs shock and vibration, thereby maintaining the fastening portion.

[0075] The resin may be a natural resin, a synthetic resin, a high-strength resin, or a resin, and may be a thermoplastic resin that can melt in a high-temperature environment. Examples of the resin include, but are not limited to, polycarbonate, polyurethane, and polyester resin. Here, the resin may be a resin that originally has the property of melting or softening in a high-temperature environment, such as a temperature environment of 100 to 250 degrees Celsius, or a resin that contains an additive that adjusts the melting point or glass transition temperature to a temperature within the high-temperature environment range. Preferred resins may include crystalline plastics belonging to the polyolefin series, such as polypropylene (PP). In addition, preferred resins may include engineering plastics such as MC (Mono Casting) nylon or polyacetal, and ether and ester polyurethanes.

[0076] Polypropylene is a polyethylene molecule in which a methyl group (CH3) is attached to every other carbon atom, and has a regularly short branched structure. Polypropylene has the advantages of being very light with a specific gravity of 0.92, a high melting temperature of 135 to 160 degrees Celsius, and a wide range of applications. In addition, polypropylene has the advantage of not being sticky when melted at high temperatures. Therefore, the bonding strength between the bolt member (400) including the first screw portion (411) and the partition frame (210) can be weakened in a predetermined high-temperature environment.

[0077] MC nylon has a structure that combines imide and ether bonds. The imide bonds provide moderate heat resistance and strength, while the ether bonds exhibit excellent processability. MC nylon has strength similar to metal, is easier to process than general plastics, and is more wear-resistant. It can withstand high temperatures up to 200 degrees Celsius and melts at temperatures higher than that, which can weaken the bonding strength between the bolt member (400) including the first screw portion (411) and the partition frame (210).

[0078] Polyacetal is a high-strength, thermoplastic plastic with a hardness close to that of metal. It can withstand temperatures ranging from approximately 80 to 120 degrees Celsius, but it also has heat resistance that allows it to withstand continuous use temperatures of up to approximately 150 degrees Celsius for short periods of time. Therefore, it can be used without difficulty in temperature environments where a battery pack (10) (10) is used under normal conditions.

[0079] The length (L) of the first screw portion (411) may correspond to the depth (D) of the fastening groove (220). That is, the length (L) of the first screw portion (411) may be formed to be the same as the depth (D) of the fastening groove (220). In this case, the first screw portion (411) may be understood as a portion of the screw portion (410) that is inserted into the fastening groove (220), and the second screw portion (412) may be understood as a portion of the screw portion (410) other than the first screw portion (411). When the length (L) of the first screw portion (411) is formed to be the same as the depth (D) of the fastening groove (220), the fastening force between the bolt member (400) and the partition frame (210) can be maintained strong under normal conditions, while the fastening force between the bolt member (400) and the partition frame (210) can be effectively weakened under a predetermined high temperature environment.

[0080] The first screw portion (411) may have a high temperature vulnerable material coated on its outer surface. In particular, referring to FIG. 4, a first coating portion (C1) may be formed by coating a specific pitch section corresponding to the first screw portion (411) on the outer surface where the male threads of the screw portion (410) are formed. The first coating portion (C1) may be composed of a high temperature vulnerable material. In this case, the first screw portion (411) may be manufactured by forming the first coating portion (C1) by coating a high temperature vulnerable material on a specific pitch section corresponding to the end of the bolt member (400) having the screw portion (410) on the partition frame (210) side, thereby providing an advantage in that the first screw portion (411) may be manufactured easily. In addition, there is an advantage in that the bonding force between the bolt member (400) and the partition frame (210) can be maintained strong under normal conditions, while the bonding force between the bolt member (400) and the partition frame (210) can be effectively weakened under a certain high temperature environment.

[0081] The second screw portion (412) may be composed of a metal material. That is, the first screw portion (411) includes a material vulnerable to high temperatures, whereas the second screw portion (412) may not include a material vulnerable to high temperatures and may be composed of a metal material. The second screw portion (412) may be composed of a metal material such as steel / SUS. Such materials are resistant to high temperatures, have excellent rigidity, and can secure high fastening strength.

[0082] The outer surface of the second screw portion (412) may be treated with a heat treatment locking coating. The heat treatment locking coating is a special type of coating applied to parts such as bolts and screws, and is applied to the surface of the corresponding parts through a heat treatment process, and the hardness and durability of the surface of the corresponding parts may be improved after the heat treatment process. In particular, referring to FIG. 4, on the outer surface where the male threads of the screw portion (410) are formed, a second coating portion (C2) may be formed by coating the remaining specific pitch section corresponding to the second screw portion (412). The second coating portion (C2) may be a coating layer treated with a heat treatment locking coating. The outer surface of the second screw portion (412) is treated with this heat treatment locking coating, thereby reinforcing the sealing between the bolt member (400) and the pack lead (300), thereby preventing the inflow of oxygen or the emission of flame, and thus effectively preventing the heat transfer phenomenon.

[0083] In this way, some pitch sections of the screw portion (410) can form a first coating portion (C1), and the remaining pitch sections can form a second coating portion (C2). In other words, the bolt member (400) can be prepared in the form of a special bolt with a different coating process for each pitch section.

[0084]

[0085] Fig. 5 is a side cross-sectional view taken along line AA' of Fig. 1, and Fig. 6 is a side cross-sectional view showing the pack lead inflated in Fig. 5.

[0086] Hereinafter, with reference to FIGS. 5 and 6, a process of swelling a pack lead (300) of a battery pack (10) according to one embodiment of the present invention will be described in detail. FIG. 5 shows the battery pack (10) before the pack lead (300) is swollen, and FIG. 6 shows the battery pack (10) with the pack lead (300) swollen.

[0087] A battery pack (10) in a normal state may have a cross-section as illustrated in FIG. 5. Since a special bolt-shaped bolt member (400) with a different coating process for each pitch section is used, the bolt member (400) is fixed to the pack lid (300) in a normal state, thereby ensuring structural safety from vibration / shock. The battery pack (10) according to one embodiment of the present invention may be configured such that the pack lid (300) swells to the state illustrated in FIG. 6 when the internal pressure of the receiving space increases.

[0088] When a thermal event occurs inside the battery pack (10), high temperature heat may be generated and the internal pressure may increase due to the discharge of venting gas and solid discharge. The high temperature heat may be transferred to the bolt member (400) and the partition frame (210) that are fastened to each other (see FIG. 5), and thus a predetermined high temperature environment may be created at the first screw portion (411) of the bolt member (400). In this high temperature environment, for example, the first coating portion (C1) of the bolt member (400) may melt and act as a lubricant, thereby weakening the fastening force of the bolt member (400) and the fixing force between the pack lid (300) and the partition frame (210). At the same time, when the increased internal pressure inside the pack case (200) acts on the pack lid (300), the bolt member (400) may eventually be uncoupled and separated from the partition frame (210). Then, a space is created by slightly separating the pack lead (300) and the partition frame (210), so that the increased internal pressure can be alleviated. If the increased internal pressure within the battery pack (10) is not alleviated and continues to be maintained, there is a concern that an event such as a fire occurring in some battery cells (100) may be transferred to other battery cells (100). However, according to the present invention, the pack lead (300) is separated by weakening the bonding force between the bolt member (400) and the partition frame (210), thereby alleviating the increase in internal pressure, thereby preventing the heat transfer phenomenon.

[0089] In addition, when the pack lid (300) is made of a material capable of elastic deformation or plastic deformation by an external force, the pack lid (300) may be further inflated toward the direction in which the internal pressure is applied (see FIG. 6). As the pack lid (300) inflates, the volume of the space between the pack case (200) and the pack lid (300) increases, so that the increased internal pressure can be alleviated, and at the same time, the flow of venting gas or solid discharge can be formed more smoothly. Through this, the heat transfer phenomenon can be effectively delayed or prevented.

[0090] In this way, according to the present invention, by causing expansion of the pack lead (300) so that the gap between the pack lead (300) and the partition frame (210) is widened, the internal space of the battery pack (10) is widened, thereby alleviating an increase in internal pressure and delaying or preventing a heat transfer phenomenon. In addition, even when the gap between the pack lead (300) and the partition frame (210) is widened, the bolt member (400) can be maintained in the through hole (310) of the pack lead (300), and, for example, the second coating portion (C2) can block the inflow of oxygen or the eruption of flames through the through hole (310). Through this battery pack (10) structure, pack safety that prevents a heat transfer phenomenon can be secured.

[0091]

[0092] FIG. 7 is a perspective view illustrating a bolt member of a battery pack according to another embodiment of the present invention.

[0093] Fig. 7 (a) shows the appearance of a bolt member (400) of a battery pack (10) according to another embodiment of the present invention, and Fig. 7 (b) shows the appearance of the bolt member (400) of Fig. 7 (a) disassembled.

[0094] According to another embodiment of the present invention, a bolt member (400) of a battery pack (10) includes a screw portion (410) including a first screw portion (411), a second screw portion (412), and a core portion (413).

[0095] The core portion (413) may be formed to extend toward the partition frame (210). The core portion (413) may be formed to extend away from the head portion (420) from the second screw portion (412), and the core portion (413) may be formed integrally with the second screw portion (412). The core portion (413) may be surrounded by a high-temperature vulnerable material. The first screw portion (411) may be formed such that the high-temperature vulnerable material surrounds the core portion (413). That is, the first screw portion (411) may correspond to a portion corresponding to the core portion (413) and the high-temperature vulnerable material surrounding the core portion (413). When the first screw portion (411) is formed as described above, the first screw portion (411) may include a larger amount of the high-temperature vulnerable material, while being stably coupled to the second screw portion (412).

[0096]

[0097] FIG. 8 is a side cross-sectional view illustrating an intermediate member further arranged in a bolt member and a partition frame in a battery pack according to one embodiment of the present invention.

[0098] Hereinafter, with reference to FIG. 8, the intermediate member (500) will be described in detail. The intermediate member (500) is positioned between the pack lid (300) and the partition frame (210), and is configured such that a bolt member (400) passes through it. The intermediate member (500) may be made of a metal material such as steel / SUS. Such materials are resistant to high temperatures and have excellent rigidity.

[0099] The intermediate member (500) can support the bolt member (400). The bolt member (400) can be supported and fixed by the intermediate member (500) before being joined to the partition frame (210).

[0100] The intermediate member (500) can support the pack lid (300) and the partition frame (210). For example, the intermediate member (500) can support the pack lid (300) from the upper side and the partition frame (210) from the lower side. In this way, since the intermediate member (500) supports the pack lid (300) and the partition frame (210), even if shock or vibration is applied to the battery pack (10), these can be effectively buffered, thereby further enhancing structural stability.

[0101] The intermediate member (500) can be in close contact with the pack lid (300) and the partition frame (210). That is, the intermediate member (500) can be in close contact with the pack lid (300) and at the same time be in close contact with the partition frame (210). The pack lid (300) and the partition frame (210) can be spaced apart from each other by maintaining a gap between them by the intermediate member (500). The intermediate member (500) can seal the space between the pack lid (300) and the partition frame (210).

[0102] The intermediate member (500) may be configured as a joint nut having a female thread formed on the inside and at least a portion of which is joined to the pack lid (300). The threaded portion (410) of the bolt member (400) may be fastened to the female thread of the joint nut. The joint nut may be joined and fixed to the pack lid (300), and an upper portion of the joint nut may be joined to the bottom surface of the pack lid (300). In this way, when the intermediate member (500) is configured as a joint nut joined to the pack lid (300), the bonding force between the bolt member (400) and the partition frame (210) may be further strengthened. The bolt member (400) may be fastened to the joint nut fixed to the pack lid (300), so that the bolt member (400) may be fixed to the pack lid (300) in advance. The bolt member (400) can be sequentially fastened to the partition frame (210) in a state where it is pre-fixed to the pack lead (300).

[0103] That is, while a plurality of intermediate members (500) are fixed to the bottom surface of the pack lid (300), a plurality of bolt members (400) are pre-fixed to the pack lid (300) through the intermediate members (500), and then the pack lid (300) is arranged to cover the opening (O) of the pack case (200), so that the plurality of bolt members (400) can be fastened to the corresponding partition frame (210) at once. Accordingly, since there is no need to individually align and fasten each bolt member (400), the assembly efficiency of the battery pack (10) is improved, and the assembly accuracy is increased.

[0104] In addition, even in a situation where a thermal event occurs inside the battery pack (10) and the bolt member (400) and the partition frame (210) are separated from each other, the bolt member (400) can still remain fixed to the pack lid (300), and the bolt member (400) can be prevented from being separated from or protruding from the pack lid (300). Therefore, even in a high-temperature environment where the pack lid (300) and the partition frame (210) are separated, the bolt member (400) can be reliably maintained in a state of being fastened to the intermediate member (500) in the through hole (310) of the pack lid (300), thereby blocking the inflow of oxygen or the eruption of flames through the through hole (310).

[0105]

[0106] FIG. 9 is a side cross-sectional view illustrating a sealing member further arranged on a bolt member and a partition frame in a battery pack according to one embodiment of the present invention.

[0107] Hereinafter, with reference to FIG. 9, the sealing member (600) will be described in detail. The sealing member (600) is configured to seal the pack lid (300) and the bolt member (400) between them. Unlike the previously described high-temperature vulnerable material, the sealing member (600) can be formed of a material that can maintain its properties even at high temperatures.

[0108] The sealing member (600) may be placed on the outer surface of the pack lid (300) that is far from the partition frame (210). The sealing member (600) may be placed between the head portion (420) of the bolt member (400) and the outer surface of the pack lid (300).

[0109] The sealing member (600) may be placed on the inner surface of the pack lid (300). In this case, the sealing member (600) may be placed between the inner surface of the pack lid (300) and the partition frame (210).

[0110] Although not shown in FIG. 9, the sealing member (600) may be placed inside the through hole (310) of the pack lead (300).

[0111] In the conventional battery pack (10), there was a disadvantage in that it was vulnerable to heat transfer phenomenon due to the inflow of oxygen or the emission of flames through the bolting holes for bolting. In the battery pack (10) according to one embodiment of the present invention, the sealing member (600) can seal between the bolting member (400) and the pack lid (300), thereby preventing the inflow of oxygen or the emission of flames, thereby more effectively preventing the heat transfer phenomenon.

[0112] Meanwhile, a combination of the configurations of FIGS. 8 and 9 is also possible. That is, a battery pack (10) equipped with both an intermediate member (500) and a sealing member (600) can also be implemented. In this case, a portion of the sealing member (600) may be configured to seal the space between the pack lid (300) and the intermediate member (500) and / or the space between the intermediate member (500) and the partition frame (210).

[0113]

[0114] Meanwhile, the battery pack (10) according to the present invention may further include various devices for controlling charging and discharging of battery cells (100), such as a BMS (Battery Management System), a current sensor, a fuse, etc., although not shown.

[0115]

[0116] FIG. 10 is a drawing illustrating a vehicle according to one embodiment of the present invention.

[0117] Referring to FIG. 10 below, the battery pack (10) according to the present invention can be applied to a vehicle (V), such as an electric vehicle or a hybrid vehicle. That is, the vehicle (V) according to the present invention can include the battery pack (10) according to the present invention. The battery pack (10) can be installed in the body frame under the vehicle seat or in the trunk space, and when installed in the vehicle, the battery pack (10) can be arranged in a reversed order as needed.

[0118] In this specification, terms indicating directions such as up, down, left, right, front, and back are used, but these terms are only for convenience of explanation, and it is obvious to those skilled in the art that these terms may vary depending on the location of the target object or the location of the observer.

[0119] As described above, although the present invention has been described by limited embodiments and drawings, the present invention is not limited thereto, and various modifications and variations are possible by a person having ordinary skill in the art to which the present invention pertains within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below.

[0120] [Explanation of symbols]

[0121] 10: Battery pack

[0122] 100: Battery Cell

[0123] 200: Pack Case

[0124] 201: Bottom

[0125] 202: Side wall

[0126] 210: Partition Frame

[0127] 211: Horizontal frame

[0128] 212: Vertical frame

[0129] 220: Contract Home

[0130] 300: Pack Lead

[0131] 400: Bolt member

[0132] 410: Screw

[0133] 411: First Screw Division

[0134] 412: Second Screw Division

[0135] 413: Core

[0136] 420: Head

[0137] 500: Intermediate member

[0138] 600: Sealing member

[0139] C1: First coating section

[0140] C2: Second coating section

[0141] O: opening

[0142] S: Reception space

[0143] V: Car

Claims

1. A pack case having a space for accommodating multiple battery cells on the inside and an opening formed on one side; A pack lid covering the above opening; A partition frame coupled to the pack case to divide the above-mentioned storage space; and A bolt member comprising at least a portion penetrating the pack lead, coupled to the partition frame, and having a first screw portion disposed at an end close to the partition frame; The above first screw part, A battery pack comprising a high-temperature vulnerable material whose properties change in a predetermined high-temperature environment, thereby weakening the bonding strength between the bolt member and the partition frame.

2. In paragraph 1, The above pack lead is, A battery pack configured to swell when the internal pressure of the above-mentioned receiving space increases.

3. In paragraph 1, The above high temperature vulnerable material is, A battery pack that melts in a certain high temperature environment and functions as a lubricant.

4. In paragraph 1, The above high temperature vulnerable material is, A battery pack composed of resin material.

5. In paragraph 1, The above first screw part, A battery pack having the above high temperature vulnerable material coated on the outer surface.

6. In paragraph 1, A fastening groove having a female thread is formed in the above partition frame so that the bolt member can be fastened. A battery pack in which the length of the first screw portion corresponds to the depth of the fastening groove.

7. In paragraph 1, The above bolt member, A battery pack further comprising a second screw portion connected to the first screw portion on a side away from the partition frame.

8. In paragraph 7, The above second screw part, A battery pack made of metal.

9. In paragraph 7, The above second screw part, A battery pack whose outer surface is heat-treated and coated with a locking agent.

10. In paragraph 7, The above second screw part, It has a core portion extending toward the above partition frame, The above first screw part, A battery pack formed by placing the above high temperature vulnerable material so as to surround the core portion.

11. In paragraph 1, A battery pack further comprising an intermediate member disposed between the pack lead and the partition frame and through which the bolt member penetrates.

12. In paragraph 11, The above intermediate member is, A battery pack in close contact with the pack lead and the partition frame.

13. In paragraph 11, The above intermediate member is, A battery pack comprising a connecting nut having a female thread formed therein and at least a portion of which is connected to the pack lead.

14. In paragraph 1, A battery pack in which a sealing member is further placed between the pack lead and the bolt member to seal them.

15. A vehicle comprising at least one battery pack according to any one of paragraphs 1 to 14.

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