Battery pack and vehicle including same

Abstract

A battery pack according to the present invention comprises: a pack case having an accommodation space in which multiple battery cells are accommodated and an opening formed at one side thereof; a pack lead covering the opening; a partition frame coupled to the pack case so as to partition the accommodation space; a bolt member having at least a portion extending through the pack lead and coupled to the partition frame; an insertion groove recessed in the partition frame; and a nut member which is press-fitted and disposed in the insertion groove and to which the bolt member is fastened, wherein at least a portion of the nut member includes a deformation part deformable by a compression force, and is made of a material having physical properties which change in a predetermined high-temperature environment, thereby weakening a coupling force between the 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. 10-2024-0047645, 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] In addition, another object of the present invention is to provide a battery pack and a vehicle including the same, in which the bonding strength between the bolt member and the partition frame and the fixing strength between the nut member and the partition frame are reinforced.

[0011] In addition, another object of the present invention is to provide a battery pack and a vehicle including the same that can effectively prevent a heat transfer phenomenon 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 improve the assemblability and productivity of the pack case.

[0013] Another purpose is to provide a battery pack with improved structural stability and a vehicle including the same.

[0014] 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.

[0015] 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.

[0016] 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; a bolt member at least partially penetrating the pack lid and coupled to the partition frame; an insertion groove formed recessed in the partition frame; and a nut member press-fitted into the insertion groove and fastened to the bolt member, wherein at least a portion of the nut member is configured as a deformable member made of a material that is deformable by a compressive force and whose physical properties change in a predetermined high-temperature environment to weaken a bonding force between the bolt member and the partition frame.

[0017] The above pack lead may be configured to swell when the internal pressure of the receiving space increases.

[0018] The cross-sectional area of ​​the above-mentioned deformation portion can be formed to be larger than the cross-sectional area of ​​the above-mentioned insertion groove.

[0019] The above-mentioned deformation part may be composed of either resin or rubber, or a composite material of the two.

[0020] The above nut member may be entirely composed of the above deformation member.

[0021] The above-mentioned deformation portion may be formed with a circular cross-section.

[0022] The above deformation portion may be formed with a polygonal cross-section.

[0023] The above-mentioned deformation section can be formed with a constant width of the longitudinal section.

[0024] The above deformation portion may not be formed with a constant width in the longitudinal section.

[0025] The above nut member has a nut portion having a female thread formed on the inside corresponding to the bolt member, and the nut portion can be placed on the pack lead side with respect to the deformation portion.

[0026] The above nut portion has a protrusion that protrudes in a direction different from the fastening direction of the bolt member, and the deformation portion can surround the protrusion.

[0027] It may further include a bushing member disposed between the pack lead and the nut member and through which the bolt member passes.

[0028] The above bushing member can be in close contact with the pack lead and the nut member.

[0029] At least a portion of the above bushing member can be joined to the pack lead.

[0030] The above bushing member may not have a female thread formed on the inside.

[0031] A sealing member may be further placed between the pack lead and the bolt member to seal them.

[0032] A vehicle according to the present invention comprises at least one battery pack according to the present invention.

[0033] According to the present invention, a battery pack and a vehicle including the same can be provided, the structural rigidity of which is further strengthened by a bolt member and a nut member.

[0034] In addition, according to the present invention, a battery pack and a vehicle including the same can be provided in which the bonding force between the bolt member and the partition frame and the fixing force between the nut member and the partition frame are reinforced by the deformation portion.

[0035] 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 nut member and a partition frame 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, which can effectively prevent a heat transfer phenomenon by causing a pack lead to swell when a thermal event occurs inside the battery pack.

[0037] In addition, according to the present invention, the assembly and productivity of the pack case are improved by the bolt member and the nut member, and a battery pack and an automobile including the same with improved structural stability can be provided.

[0038] In addition, according to the present invention, a battery pack and an automobile including the same can be provided, in which assembly and productivity are further improved by the bushing member.

[0039] 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 a sealing member.

[0040] 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.

[0041] 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.

[0042] FIG. 1 is a perspective view showing the overall appearance of a battery pack according to one embodiment of the present invention.

[0043] Figure 2 is a perspective view showing the battery pack of Figure 1 in an exploded state.

[0044] FIG. 3 is a cross-sectional side view showing a bolt member and a nut member combined in a battery pack according to one embodiment of the present invention.

[0045] FIG. 4 is a cross-sectional side view showing a disassembled state of a bolt member and a nut member in a battery pack according to one embodiment of the present invention.

[0046] Figure 5 is a cross-sectional view taken along line AA' of Figure 1.

[0047] Figure 6 is a cross-sectional side view showing the pack lead inflated in Figure 5.

[0048] FIG. 7 is a perspective view illustrating a nut member of a battery pack according to a modified example of one embodiment of the present invention.

[0049] FIG. 8 is a cross-sectional side view showing a nut member of a battery pack according to another modified example of one embodiment of the present invention.

[0050] FIG. 9 is a cross-sectional side view illustrating a nut member of a battery pack according to another embodiment of the present invention.

[0051] FIG. 10 is a side cross-sectional view illustrating a battery pack according to one embodiment of the present invention in which a bushing member is further arranged in addition to a bolt member and a nut member.

[0052] FIG. 11 is a side cross-sectional view illustrating a sealing member further arranged on a bolt member and a nut member in a battery pack according to one embodiment of the present invention.

[0053] FIG. 12 is a drawing showing a vehicle according to one embodiment of the present invention.

[0054] 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.

[0055] 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.

[0056]

[0057] 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 combined appearance of a bolt member and a nut member in a battery pack according to one embodiment of the present invention, and FIG. 4 is a side cross-sectional view showing an exploded appearance of a bolt member and a nut member in a battery pack according to one embodiment of the present invention.

[0058] Hereinafter, a battery pack according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4. A battery pack (10) according to an embodiment of the present invention includes a pack case (200), a pack lid (lid, 300), a partition frame (210), a bolt member (400), and a nut member (500).

[0059] 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).

[0060] 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.

[0061] In the accommodation space (S) of the pack case (200), the battery cells (100) may be accommodated 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 accommodated 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 accommodated 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 arranged on both sides or one side of the module case.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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 member (400) may be coupled to the partition frame (210) by being fastened to the nut member (500).

[0067] 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 screw 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 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.

[0068] A through hole (310) may be formed in the pack lid (300) so that the bolt member (400) may pass through it. The through holes (310) may be formed in a corresponding number at a position 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).

[0069] An insertion groove (220) is formed in the partition frame (210). The insertion groove (220) may be formed in an area of ​​the partition frame (210) facing the pack lid (300). The insertion groove (220) may be formed at the upper end of the partition frame (210). A screw thread may not be formed in the insertion groove (220), and in this case, separate tap processing is unnecessary in the insertion groove (220), thereby reducing the time and cost required for processing the insertion groove (220).

[0070] The nut member (500) is configured to be pressed into and placed in the insertion groove (220), and the bolt member (400) is fastened. A fastening groove (501) corresponding to the threaded portion (410) of the bolt member (400) may be formed in the nut member (500) so that the bolt member (400) may be fastened thereto. The fastening groove (501) may be formed with an open upper side so that the bolt member (400) may be inserted therein. A female thread corresponding to the male thread formed in the threaded portion (410) of the bolt member (400) may be formed on the inside of the fastening groove (501).

[0071] The nut members (500) can be arranged in a corresponding number at positions corresponding to the bolt members (400). A plurality of nut members (500) can be arranged spaced apart from each other. The spacing between a pair of adjacent nut members (500) can be formed differently from the spacing between another pair of adjacent nut members (500). The nut members (500) can be arranged only in a part of the partition frame (210) or can be arranged in the entire area of ​​the partition frame (210).

[0072] When multiple bolt members (400) and nut members (500) are all fastened to the pack lead (300), the pack lead (300) is placed on the upper side of the opening (O) of the pack case (200), and each nut member (500) is aligned with its corresponding insertion groove (220), and then the pack lead (300) is pressed toward the partition frame (210), each nut member (500) can be pressed into its corresponding insertion groove (220) at once. By this simple assembly process, the assembly efficiency and productivity of the battery pack (10) can be improved.

[0073] The nut member (500) is at least partially composed of a deformation portion (510). The deformation portion (510) can be deformed by a compressive force. The deformation portion (510) can be press-fitted into an insertion groove (220) formed in the partition frame (210). That is, the deformation portion (510) can be inserted into the insertion groove (220) in a compressed state. The deformation portion (510) can be composed of an elastic material. The deformation portion (510) can also be composed of a hard or high-strength material in order to form a strong restoring force or repulsive force when deformed, such as by compression. In this case, as the deformation part (510) is inserted into the insertion groove (220) in a compressed state and pressed in, the deformation part (510) can exert a strong restoring force or repulsive force on the inside of the insertion groove (220) due to the property of the deformation part (510) to be restored to its original state, and at the same time, the insertion groove (220) exerts a strong vertical force on the deformation part (510) side. Therefore, the deformation part (510) is strongly fixed within the insertion groove (220), so that the structural rigidity of the battery pack (10) can be further strengthened.

[0074] The deformation portion (510) may constitute the entirety of the nut member (500). In this case, the deformation portion (510) itself may constitute the nut member (500). In addition, a fastening groove (501) into which a bolt member (400) is fastened may be formed on the inside of the deformation portion (510). In this way, when the deformation portion (510) constitutes the entirety of the nut member (500), the structure of the nut member (500) may be simplified, thereby facilitating the manufacture of the nut member (500). For convenience of explanation, in FIGS. 3 and 4, the deformation portion (510) is illustrated as constituting the entirety of the nut member (500), but is not limited thereto.

[0075] Alternatively, the deformation portion (510) may form a part of the nut member (500). In the case where the deformation portion (510) forms a part of the nut member (500), the nut member (500) may have a separate nut member (520) in addition to the deformation portion (510), as in the nut member (500) of the battery pack (10) according to another embodiment of the present invention described below with reference to FIG. 9.

[0076] The cross-sectional area of ​​the deformation portion (510) may be formed to be larger than the cross-sectional area of ​​the insertion groove (220). Preferably, the cross-sectional area of ​​the deformation portion (510) may be formed to be slightly larger than the cross-sectional area of ​​the insertion groove (220). Here, the cross-sectional area refers to the cross-sectional area of ​​a cross-section based on the penetration direction or the fastening direction of the bolt member (400). As the cross-sectional area of ​​the deformation portion (510) is formed to be larger than the cross-sectional area of ​​the insertion groove (220), the deformation portion (510) may have a greater chance of being compressed when inserted into the insertion groove (220). The difference between the cross-sectional area of ​​the deformation portion (510) and the cross-sectional area of ​​the insertion groove (220) may be formed to be an appropriate difference such that the deformation portion (510) can be easily pressed into the insertion portion, while also being sufficiently strongly fixed to the insertion portion in a compressed state.

[0077] The penetration direction or fastening direction of the bolt member (400) may be a direction parallel to the Z direction as illustrated in FIGS. 1 to 4. When the bolt member (400) is inserted into the insertion groove (220) in the Z direction and compressed, the restoring force or repulsive force applied from the deformation portion (510) to the insertion groove (220) and the vertical force applied from the insertion groove (220) to the deformation portion (510) may be formed parallel to the XY plane.

[0078] The cross-sectional shape of the deformation portion (510) may be formed in a shape similar to or similar to the cross-sectional shape of the insertion portion. For example, the insertion portion may be formed by being sunken into a cylindrical shape, and the deformation portion (510) may be formed in a cylindrical shape whose diameter (D1) is slightly larger than the diameter (D2) of the insertion portion (see FIG. 4). In this case, when the cross-section of the deformation portion (510) is formed in a circular shape, even if the deformation portion (510) is rotated around the central axis, it can be inserted into the insertion portion in the same manner, so there is an advantage in that the deformation portion (510) can be easily press-fitted into the insertion portion. However, the shape of the deformation portion (510) is not limited thereto, and may be formed in various shapes as described below with reference to FIGS. 7 and 8.

[0079] The deformation portion (510) may be formed with a constant width. Specifically, the width of the deformation portion (510) may be maintained constant from one side to the other. Here, the width refers to the width when the penetration direction or fastening direction of the bolt member (400) is taken as the longitudinal direction.

[0080] For example, the deformation portion (510) may be formed in a cylindrical shape with a diameter of the same size from top to bottom. In this case, when the width of the deformation portion (510) is formed to be constant, the deformation portion (510) can be easily pressed into the insertion portion, and the deformation portion (510) can be uniformly compressed from one side to the other.

[0081] The nut member (500) is made of a material that can sufficiently secure structural rigidity in a normal state. The deformation portion (510) of the nut member (500) is made of a 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). The material may be referred to as a high-temperature vulnerable material. 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 such as melting, weakening of brittleness, or melting and weakening of brittleness at the same time.

[0082] When a high temperature and high pressure thermal event occurs inside the battery pack (10), the properties of the deformation portion (510) of the nut member (500) change, which may weaken 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.

[0083] 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, the conventional battery pack (10) was vulnerable to the heat transfer phenomenon because the pack lid (300) was fixed so that it could not swell due to the strong bolting.

[0084] In contrast, in the battery pack (10) according to one embodiment of the present invention, by improving the nut member (500), the structural stability is secured to a degree that the vibration and impact test conditions can be met in normal conditions such as normal conditions, while in the event of a thermal event such as a battery cell (100) ignition, the bonding force between the bolt member (400) and the partition frame (210) is weakened so that the pack lid (300) can swell, thereby preventing a heat transfer phenomenon. This effect will be discussed in more detail in the following description with reference to FIGS. 5 and 6.

[0085] The deformation portion (510) of the nut member (500) may be composed of either resin or rubber, or a composite of the two. That is, the high-temperature vulnerable material may be composed of either resin or rubber, or a composite of the two. 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).

[0086] Meanwhile, the nut member (500) may be composed of an elastic material as described above, and may also be composed of a hard or high-strength material to form a strong restoring force or repulsive force when compressed or deformed. Accordingly, when the nut member (500) is inserted and pressed into the insertion groove (220) in a compressed state, the nut member (500) can exert a strong restoring force or repulsive force toward the insertion groove (220).

[0087] The resin absorbs shock and vibration to maintain the joint. 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 engineering plastics such as MC (Mono Casting) nylon or polyacetal, and ether and ester polyurethanes.

[0088] 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 typical plastics, and is more wear-resistant. It can withstand high temperatures up to 200 degrees Celsius and melts at temperatures higher than that, weakening the bond between the bolt member (400) and the partition frame (210) through the deformation portion (510).

[0089] 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) is used under normal conditions.

[0090] The rubber may be natural rubber, synthetic rubber, high-strength rubber, etc., and may be a thermoplastic rubber that can melt in a high-temperature environment. For example, the rubber may be a silicone elastomer, an epoxy elastomer, a polyurethane elastomer, etc., but these are only examples and are not limited thereto. Here, the rubber may be a rubber that originally has the property of melting or softening in a high-temperature environment, which may be a temperature environment of 100 to 250 degrees Celsius, or a rubber that contains an additive that adjusts the melting point to a temperature within the high-temperature environment range.

[0091] Here, the weakening of the bonding force between the bolt member (400) and the partition frame (210) may include the following two cases. The first case is when the fixing force between the nut member (500) and the insertion groove (220) is weakened. In this case, the nut member (500) and the insertion portion are placed in a state where they are easily separated from each other (hereinafter referred to as the first state). The second case is when the fastening force between the bolt member (400) and the nut member (500) is weakened while the nut member (500) is fixedly maintained in the insertion groove (220). In this case, the bolt member (400) and the nut member (500) are placed in a state where they are easily separated from each other (hereinafter referred to as the second state).

[0092]

[0093] 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.

[0094] Hereinafter, with reference to FIGS. 5 and 6, a process of swelling of a pack lead (300) of a battery pack (10) according to one embodiment of the present invention will be described in detail. FIG. 5 illustrates the battery pack (10) before the pack lead (300) is swollen, and FIG. 7 illustrates the battery pack (10) with the pack lead (300) swollen.

[0095] A battery pack (10) in a normal state may have a cross-section as illustrated in FIG. 5. A battery pack (10) according to one embodiment of the present invention may be configured so that the pack lead (300) swells to a state as illustrated in FIG. 6 when the internal pressure of the receiving space increases.

[0096] 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 nut member (500) that are connected to each other (see FIG. 5), and thus a predetermined high temperature environment may be created in the nut member (500). In this high temperature environment, the bonding strength of the bolt member (400) with the partition frame (210) is weakened. 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 be decoupled and separated from the partition frame (210). Then, a space may be created as the pack lid (300) and the partition frame (210) are slightly separated, and the increased internal pressure may be relieved. If the increased internal pressure within the battery pack (10) is not relieved 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 increase in internal pressure is relieved by spacing out the pack lead (300) through weakening the bonding force between the bolt member (400) and the partition frame (210), thereby preventing the heat transfer phenomenon.

[0097] 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.

[0098] Meanwhile, in FIG. 6, a first state is shown in which the nut member (500) is separated from the insertion groove (220) while the bolt member (400) and the nut member (500) are still fastened to each other. However, unlike what is shown in FIG. 6, a second state in which the bolt member (400) is separated from the nut member (500) while the nut member (500) is still fixed to the insertion groove (220) is also possible.

[0099]

[0100] FIG. 7 is a perspective view illustrating a nut member of a battery pack according to a modified example of one embodiment of the present invention, and FIG. 8 is a side cross-sectional view illustrating a nut member of a battery pack according to another modified example of one embodiment of the present invention.

[0101] Hereinafter, with reference to FIGS. 7 and 8, a nut member (500) of a battery pack (10) according to a modified example of one embodiment of the present invention and another modified example will be described in detail. For convenience of explanation, FIGS. 7 and 8 illustrate that the modified portion (510) constitutes the entire nut member (500).

[0102] Referring to FIG. 7, the nut member (500) of the battery pack (10) according to a modified example of one embodiment of the present invention may have a polygonal cross-section of a deformation portion (510). For example, the cross-section of the deformation portion (510) may be formed in a rectangular shape as illustrated in FIG. 7, and although not illustrated in the drawing, it may also be formed in various polygonal shapes such as a triangle or a pentagon. In this way, when the cross-section of the deformation portion (510) is formed in a polygonal shape, the rotation of the deformation portion (510) press-fitted into the insertion groove (220) is prevented, so that the nut member (500) can be more stably fixed to the partition frame (210), while the fastening force between the nut member (500) and the bolt member (400) can be maintained.

[0103] Referring to FIG. 8, in a battery pack (10) according to another modified example of one embodiment of the present invention, the nut member (500) may not have a uniform width of the deformation portion (510). Specifically, the width of the deformation portion (510) may not be uniform from one side to the other. Here, the width refers to the width when the penetration direction or fastening direction of the bolt member (400) is taken as the longitudinal direction.

[0104] For example, as illustrated in FIG. 8, the upper width (W1) of the deformation portion (510) may be formed differently from the lower width (W2). If the lower width (W2) is formed larger than the upper width (W1), when the deformation portion (510) is press-fitted into the insertion groove (220), the fixing force between the nut member (500) and the partition frame (210) may be further strengthened. Conversely, if the upper width (W1) is formed larger than the lower width (W2), the press-fitting of the deformation portion (510) into the insertion groove (220) may be further facilitated.

[0105] Meanwhile, the deformation portion (510) may be formed such that the central portion between the upper and lower sides has a convex central width (W3) greater than the upper width (W1) or the lower width (W2). Conversely, the central portion may be formed such that the central portion has a concave central width (W3) less than the upper width (W1) or the lower width (W2). In this case, when the central portion is formed convex or concave, the nut member (500) can be more strongly fixed to the partition frame (210).

[0106]

[0107] FIG. 9 is a cross-sectional side view illustrating a nut member of a battery pack according to another embodiment of the present invention.

[0108] Hereinafter, with reference to FIG. 9, a nut member (500) of a battery pack (10) according to another embodiment of the present invention will be described in detail. The nut member (500) of the battery pack (10) according to another embodiment of the present invention includes a nut portion (520). That is, the nut member (500) is configured together with a deformation portion (510) and a separate nut portion (520).

[0109] The nut portion (520) may have a female thread corresponding to the male thread of the bolt member (400). That is, the fastening groove (501) described above may be formed in the nut portion (520). The nut portion (520) may be arranged on the pack lid (300) side with respect to the deformation portion (510). The deformation portion (510) may be arranged on the side farther from the pack lid (300) with respect to the nut portion (520). As illustrated in FIG. 9, the nut portion (520) may be arranged on the upper side, and the deformation portion (510) may be arranged on the lower side of the nut portion (520). When the nut member (520) and the deformation member (510) are arranged in this manner, the fastening between the bolt member (400) and the nut member (500) can be stably formed, while at the same time, the pressure fitting of the deformation member (510) into the insertion groove (220) can be facilitated. The nut member (500) can be made of a metal material such as steel / SUS. Such materials are resistant to high temperatures, have excellent rigidity, and can secure high fastening force.

[0110] The nut member (500) may be composed of a nut member (500) having a metal nut corresponding to the nut portion (520), such as a urethane pusher, and a resin cover such as a urethane cover corresponding to the deformation portion (510).

[0111] The nut portion (520) may have a protrusion (521). The protrusion (521) may protrude in a direction different from the fastening direction (or penetration direction) of the bolt member (400), and the deformation portion (510) may surround the protrusion (521). The protrusion (521) may be formed integrally with the nut portion (520). The protrusion (521) may be formed on the lower side of the nut portion (520). By the protrusion (521), the deformation portion (510) may be more stably and strongly coupled to the nut portion (520).

[0112]

[0113] FIG. 10 is a side cross-sectional view illustrating a battery pack according to one embodiment of the present invention in which a bushing member is further arranged in addition to a bolt member and a nut member.

[0114] Hereinafter, referring to FIG. 10, the bushing member (600) will be described in detail. The bushing member (600) is arranged between the pack lead (300) and the nut member (500), and is configured such that the bolt member (400) passes through it. The bushing member (600) may be made of a metal material such as steel / SUS. Such materials are resistant to high temperatures and have excellent rigidity. By virtue of the bushing member (600), the fastening force between the bolt member (400) and the nut member (500) can be further strengthened.

[0115] The bushing member (600) can support the bolt member (400). The bolt member (400) can be supported by the bushing member (600) before being fastened to the nut member (500). The bushing member (600) can guide the fastening or penetration of the bolt member (400).

[0116] The bushing member (600) can support the pack lead (300) and the nut member (500). For example, the bushing member (600) can support the pack lead (300) from the upper side and the nut member (500) from the lower side. In this way, since the bushing member (600) supports the pack lead (300) and the nut member (500), even if shock or vibration is applied to the battery pack (10), these can be effectively buffered, thereby further enhancing structural stability.

[0117] The bushing member (600) can be in close contact with the pack lead (300) and the nut member (500). That is, the bushing member (600) can be in close contact with the pack lead (300) and at the same time be in close contact with the nut member (500). The pack lead (300) and the nut member (500) can be spaced apart from each other while maintaining a gap between them by the bushing member (600). The bushing member (600) can also seal the space between the pack lead (300) and the nut member (500).

[0118] At least a portion of the bushing member (600) can be joined to the pack lead (300). That is, the bushing member (600) can be joined and fixed to the pack lead (300), and the upper portion of the bushing member (600) can be joined to the bottom surface of the pack lead (300). In this case, the plurality of bushing members (600) fixed to the bottom surface of the pack lead (300) can all guide the penetration of the corresponding bolt members (400), so that the plurality of bolt members (400) in a state before fastening can be easily aligned.

[0119] A female thread may not be formed on the inside of the bushing member (600). That is, a female thread corresponding to the male thread of the bolt member (400) is not formed on the inside of the bushing member (600), and the bolt member (400) may simply pass through the bushing member (600). In this case, the bushing member (600) may guide the penetration of the bolt member (400). The bolt member (400) is inserted into the female thread and is fastened to the female thread. However, in the case where a female thread is not formed on the inside of the bushing member (600) as described above, the bolt member (400) passes through the bushing member (600) as is and is fastened only to the female thread formed in the fastening groove (501) of the nut member (500), and as a result, the length or depth to which the bolt member (400) is fastened may be reduced. In this case, the time required for fastening the bolt member (400) is shortened, so that the assembly and productivity of the battery pack (10) can be improved.

[0120]

[0121] FIG. 11 is a side cross-sectional view illustrating a sealing member further arranged on a bolt member and a nut member in a battery pack according to one embodiment of the present invention.

[0122] Hereinafter, with reference to FIG. 11, the sealing member (700) will be described in detail. The sealing member (700) 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 (700) can be formed of a material that can maintain its properties even at high temperatures.

[0123] The sealing member (700) may be placed on the outer surface of the pack lid (300) that is far from the partition frame (210). The sealing member (700) may be placed between the head portion (420) of the bolt member (400) and the outer surface of the pack lid (300).

[0124] The sealing member (700) may be placed on the inner surface of the pack lid (300). In this case, the sealing member (700) may be placed between the inner surface of the pack lid (300) and the partition frame (210).

[0125] Although not shown in Fig. 11, the sealing member (700) may be placed inside the through hole (310) of the pack lead (300).

[0126] 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 (700) can implement a seal between the bolting member (400) and the pack lid (300), thereby preventing the inflow of oxygen or the emission of flames, thereby effectively preventing the heat transfer phenomenon.

[0127] Meanwhile, a combination of FIGS. 10 and 11 is also possible. That is, a battery pack (10) equipped with both a bushing member (600) and a sealing member (700) can also be implemented. In this case, a portion of the sealing member (700) may be configured to seal the space between the pack lead (300) and the bushing member (600) and / or the space between the bushing member (600) and the nut member (500).

[0128]

[0129] 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.

[0130]

[0131] FIG. 12 is a drawing showing a vehicle according to one embodiment of the present invention.

[0132] Referring to FIG. 12 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.

[0133] 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.

[0134] 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.

[0135] [Explanation of symbols]

[0136] 10: Battery pack

[0137] 100: Battery Cell

[0138] 200: Pack Case

[0139] 201: Bottom

[0140] 202: Side wall

[0141] 210: Partition Frame

[0142] 211: Horizontal frame

[0143] 212: Vertical frame

[0144] 220: Insertion groove

[0145] 300: Pack Lead

[0146] 310: Through hole

[0147] 400: Bolt member

[0148] 410: Screw

[0149] 420: Head

[0150] 500: Nutless

[0151] 501: Contract Home

[0152] 510: Transformation section

[0153] 520: Nut section

[0154] 521: Protrusion

[0155] 600: Bushing member

[0156] 700: Sealing member

[0157] O: opening

[0158] S: Reception space

[0159] 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 partition the above-mentioned accommodation space; A bolt member, at least a portion of which penetrates the pack lead and is joined to the partition frame; An insertion groove formed in the above partition frame; and It includes a nut member that is pressed into and placed in the above insertion groove and to which the bolt member is fastened, At least a portion of the above nut member, A battery pack comprising a deformable portion made of a material that can be deformed by compressive force and has properties that change in a predetermined high-temperature environment, thereby weakening the bonding force 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 storage space increases.

3. In paragraph 1, The cross-sectional area of ​​the above-mentioned deformation section is A battery pack formed to have a cross-sectional area larger than that of the above insertion groove.

4. In paragraph 1, The above deformation part is, A battery pack composed of either resin or rubber, or a composite of the two.

5. In paragraph 1, The above nut member is, A battery pack whose entire body is composed of the above-described deformation portion.

6. In paragraph 1, The above deformation part is, A battery pack whose cross-section is circular.

7. In paragraph 1, The above deformation part is, A battery pack whose cross-section is formed into a polygon.

8. In paragraph 1, The above deformation part is, A battery pack in which the width of the cross-section is formed at a constant level.

9. In paragraph 1, The above deformation part is, A battery pack whose cross-sectional width is not uniform.

10. In paragraph 1, The above nut member is, A nut part having a female thread formed on the inside corresponding to the bolt member is provided, The above nut part, A battery pack placed on the pack lead side based on the above-mentioned deformation portion.

11. In paragraph 10, The above nut part, It has a protrusion that protrudes in a direction different from the fastening direction of the above bolt member, The above deformation part is, A battery pack that surrounds the above protrusion.

12. In paragraph 1, A battery pack further comprising a bushing member disposed between the pack lead and the nut member and through which the bolt member passes.

13. In paragraph 12, The above bushing member, A battery pack in close contact with the above pack lead and the above nut member.

14. In paragraph 12, The above bushing member, A battery pack wherein at least a portion of the battery pack is bonded to the pack lead.

15. In paragraph 12, The above bushing member, A battery pack that does not form internal screw holes.

16. 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.

17. A vehicle comprising at least one battery pack according to any one of claims 1 to 16.

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