Battery module with improved thermal propagation preventing structure

Abstract

The disclosed invention relates to a battery module, wherein, in one example, the module housing accommodates a plurality of battery cells, a pair of high-voltage terminals provided on the front surface of the module housing, a pair of module lifting holes provided between the high-voltage terminals, a thermal barrier that surrounds a portion of the front surface of the module housing including the high-voltage terminals and has a fastening hole formed through its upper surface, and a fastening member installed through the module lifting hole and the fastening hole to fix the thermal barrier to the module lifting hole.

Description

Technology Field

[0001] The present invention relates to a battery module, and more specifically, to a battery module capable of effectively preventing heat propagation in which a thermal runaway phenomenon generated in a battery cell within the battery module spreads to other surrounding battery modules. Background Technology

[0002] Unlike primary batteries, secondary batteries are rechargeable and are currently the subject of extensive research and development due to their potential for miniaturization and high capacity. The demand for secondary batteries as an energy source is increasing rapidly due to the growing technological development and demand for mobile devices, as well as the rise of electric vehicles and energy storage systems driven by the contemporary need for environmental protection.

[0003] Rechargeable batteries are classified into coin batteries, cylindrical batteries, prismatic batteries, and pouch batteries according to the shape of the battery case. In rechargeable batteries, the electrode assembly mounted inside the battery case is a power generation device capable of charging and discharging, consisting of a laminated structure of electrodes and separators.

[0004] Since secondary batteries require continuous use over long periods, it is necessary to effectively control the heat generated during the charging and discharging process. If the cooling of the secondary battery is not performed smoothly, a positive feedback chain reaction occurs where the temperature rise causes an increase in current, and this increase in current again causes a temperature rise, eventually leading to a catastrophic state of thermal runaway.

[0005] In addition, when secondary batteries are grouped in the form of modules or packs, a thermal propagation phenomenon occurs in which surrounding secondary batteries are continuously overheated due to thermal runaway in one secondary battery. That is, when thermal runaway occurs in a battery module within a battery pack, a large amount of conductive dust, gas, and flames are ejected from the high-voltage terminal of the battery module, and consequently, dust accumulates on the high-voltage terminal of an adjacent battery module, and the thermal propagation phenomenon is triggered by heat transfer from the gas and flames.

[0006] In order to prevent such heat propagation, measures were taken to add a flame-retardant thermal barrier to prevent ejected material and high heat from being transferred to adjacent battery modules, but there was a problem in that the thermal barrier did not perform its function properly because it frequently displaced from its proper position due to the high temperature and high pressure material ejected from the battery modules. Prior art literature

[0007] Korean Patent Publication No. 2021-0059433 (Published May 25, 2021) The problem to be solved

[0008] The purpose of the present invention is to provide a battery module capable of more effectively blocking conductive dust, gas, and flames ejected in large quantities from high-voltage terminals by ensuring that the thermal barrier firmly maintains its position in a situation where thermal runaway occurs in the battery module.

[0009] However, the technical problems that the present invention aims to solve are not limited to those described above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description of the invention below. means of solving the problem

[0010] The present invention relates to a battery module, wherein, in one example, the module housing accommodates a plurality of battery cells; a pair of high-voltage terminals provided on the front surface of the module housing; a pair of module lifting holes provided between the high-voltage terminals; a thermal barrier covering a portion of the front surface of the module housing including the high-voltage terminals, with a fastening hole formed through its upper surface; and a fastening member installed through the module lifting hole and the fastening hole to fix the thermal barrier to the module lifting hole.

[0011] In one embodiment of the present invention, the module lifting hole is formed on the upper surface of a module lifting rib that forms a space open to the front of the module housing, while having a step difference with respect to the upper surface of the module housing.

[0012] In addition, the thermal barrier may form a folded shape that wraps around the upper surface and the front surface of the high-voltage terminal.

[0013] In addition, the width of the thermal barrier can correspond to the front width of the module housing.

[0014] And, the fastening member may include a nut inserted into the interior of the module lifting rib, a washer disposed on the upper surface of the module lifting rib, and a bolt that passes through the fastening hole and the washer and the module lifting hole and screws into the nut.

[0015] Here, it may be preferable for the nut to be installed inside the module lifting rib so as not to rotate together with the rotation of the bolt.

[0016] Alternatively, the fastening member may be a rivet installed by penetrating the fastening hole and the module lifting hole.

[0017] In addition, heat-resistant silicone may be applied to the contact surface between the thermal barrier and the module housing.

[0018] Meanwhile, according to another embodiment of the present invention, the battery module further comprises a busbar and a busbar cover surrounding the busbar, and both ends of the busbar are electrically connected to each other while being mechanically fixed to high-voltage terminals of adjacent module housings.

[0019] The above busbar cover may include: a lower busbar cover having a connection hole on which the busbar is seated and which exposes the busbar to the high voltage terminal; and an upper busbar cover that is coupled with the lower busbar cover to wrap the busbar and has a cover fastening hole corresponding to the module lifting hole.

[0020] In addition, the busbar lower cover and the busbar upper cover can be joined together by a hook structure.

[0021] In addition, it may be desirable for the thermal barrier to wrap around the busbar cover.

[0022] Here, the fastening member can be fastened to the module lifting hole by penetrating the fastening hole of the thermal barrier and the cover fastening hole of the busbar cover.

[0023] These fastening members may be a nut inserted into the interior of the module lifting rib, and a bolt that is screwed onto the nut by penetrating the fastening hole, the cover fastening hole, and the module lifting hole, or a rivet installed by penetrating the fastening hole, the cover fastening hole, and the module lifting hole.

[0024] Additionally, a concave stepped surface corresponding to the step formed by the module lifting rib with respect to the upper surface of the module housing may be formed around the fastening hole of the thermal barrier. Effects of the invention

[0025] The battery module of the present invention, having the above-described configuration, can mechanically and firmly secure the thermal barrier using the module lifting hole already provided in the module housing to handle the heavy battery module. Accordingly, even if thermal runaway occurs in the battery module and a large amount of discharge spills from the high-voltage terminal, the thermal barrier can firmly maintain its position, thereby effectively blocking or delaying heat propagation to other surrounding battery modules.

[0026] In addition, the battery module of the present invention enables more effective prevention of heat propagation by protecting the high-voltage terminal and the busbar with a flame-retardant cover.

[0027] However, the technical effects obtainable through the present invention are not limited to those described above, and other unmentioned effects will be clearly understood by a person skilled in the art from the description of the invention below. Brief explanation of the drawing

[0028] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. FIG. 1 is a drawing illustrating an example of a battery pack having a plurality of battery modules of the present invention. FIG. 2 is a drawing showing a battery module without a thermal barrier. FIG. 3 is an enlarged view of the front of a battery housing equipped with a thermal barrier. FIG. 4 is an exploded perspective view illustrating the mounting structure of a thermal barrier. FIG. 5 is a drawing illustrating a battery module equipped with a thermal barrier. FIG. 6 is a drawing illustrating a busbar cover provided in another embodiment of the present invention. FIG. 7 is a drawing illustrating a structure in which a busbar cover is mounted on a battery module. FIG. 8 is a drawing illustrating a battery module including a thermal barrier and a busbar cover. Fig. 9 is a cross-sectional view taken along the line "AA" in Fig. 8. FIG. 10 is a drawing illustrating another embodiment of a thermal barrier. Specific details for implementing the invention

[0029] The present invention is capable of various modifications and may have various embodiments, and specific embodiments are to be described in detail below.

[0030] However, this is not intended to limit the invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0031] In the present invention, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0032] Furthermore, in the present invention, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only cases where it is "immediately above" the other part, but also cases where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only cases where it is "immediately below" the other part, but also cases where there is another part in between. Additionally, in the present application, being "placed on" may include cases where it is placed on the lower part as well as on the upper part.

[0034] The present invention relates to a battery module, wherein, in one example, the module housing accommodates a plurality of battery cells, a pair of high-voltage terminals provided on the front surface of the module housing, a pair of module lifting holes provided between the high-voltage terminals, a thermal barrier having a fastening hole formed through its upper surface while covering a portion of the front surface of the module housing including the high-voltage terminals, and a fastening member installed through the module lifting hole and the fastening hole to fix the thermal barrier to the module lifting hole.

[0035] The battery module of the present invention, having such a configuration, can mechanically and firmly secure the thermal barrier using the module lifting hole already provided in the module housing to handle the heavy battery module. Accordingly, even if thermal runaway occurs in the battery module and a large amount of discharge spills from the high-voltage terminal, the thermal barrier can firmly maintain its position, thereby effectively blocking or delaying heat propagation to other surrounding battery modules.

[0037] Hereinafter, specific embodiments of a battery module according to the present invention will be described in detail with reference to the attached drawings. For reference, the directions of front, back, up, down, left, and right used to specify relative positions in the following description are intended to aid in understanding the invention, and unless otherwise specifically defined, the directions shown in the drawings are used as the reference.

[0039] [First embodiment]

[0040] FIG. 1 is a drawing illustrating an example of a battery pack (10) in which a plurality of battery modules (100) of the present invention are mounted. The battery pack (10) includes a pack case (12) that is structured as a frame structure capable of securing structural rigidity of the battery pack (10) while protecting the mounted battery modules (100) and forming a space to accommodate a plurality of battery modules (100). The battery pack (10) illustrated exemplarily in FIG. 1 is equipped with a total of eight battery modules (100) and is arranged so that the front of the battery modules (100) faces toward a center frame (14) that crosses the center of the pack case (12). A high-voltage terminal (120) for connecting a bus bar (500) is positioned on the front of the battery module (100), and a thermal barrier (200) for protecting it is mounted on the battery module (100).

[0041] FIG. 2 illustrates a battery module (100) mounted on the battery pack (10) of FIG. 1, wherein the thermal barrier (200) shown in FIG. 1 is omitted. A plurality of battery cells are housed within the battery module (100) (the internal battery cells are not shown in the drawing), and these plurality of battery cells are connected to each other as a series and / or parallel circuit so that charging and discharging occur at a specified voltage and current. A high-voltage terminal (120) is provided on the outside of the battery module (100) as an input / output terminal for the electrically connected plurality of battery cells.

[0042] FIG. 3 is an enlarged view of the front of a module housing (110) in which a thermal barrier (200) is installed. The module housing (110) is a part that forms the body of a battery module (100) that accommodates a plurality of battery cells, and a pair of high-voltage terminals (120) are provided on the front of the module housing (110).

[0043] Additionally, a pair of module lifting holes (132) are provided between the high-voltage terminals (120), which consist of a pair of positive and negative electrodes. Since the battery module (100) equipped with multiple battery cells is quite heavy, a lifting device is used to perform the operation of storing or removing the battery pack (10). The module lifting holes (132) are provided in the module housing (110) for handling the battery module (100), and a pair of module lifting holes (132) are provided on the front and rear of the module housing (110) respectively for balance.

[0044] The thermal barrier (200) is a barrier member for blocking a large amount of conductive dust, gas, and flames discharged at high temperature and high pressure toward the high voltage terminal (120) when thermal runaway occurs within the battery module (100). To this end, the thermal barrier (200) is formed to cover a portion of the front of the module housing (110) and is made of a flame-retardant material capable of withstanding high temperatures, such as mica. Additionally, a fastening hole (210) for fixing to the module housing (110) is formed through the upper surface of the thermal barrier (200).

[0045] The thermal barrier (200) is fixed to the module housing (110) by means of a fastening member (300). Conventionally, the thermal barrier (200) was fixed to the module housing (110) by attaching it with imide tape or heat-resistant silicone. Although the attachment method is simple, it has the disadvantage of insufficient fixing power of the thermal barrier (200). In particular, it was difficult to trust the reliable blocking function because the thermal barrier (200) was displaced from its proper position by high temperature and high pressure ejections. In contrast, the present invention significantly improves the mechanical fixing power of the thermal barrier (200) by installing the fastening member (300) through the module lifting hole (132) and the fastening hole (210).

[0046] Referring to FIG. 3, the module lifting hole (132) is formed on the upper surface of the module lifting rib (130), which forms a space open to the front of the module housing (110) while having a step difference with respect to the upper surface of the module housing (110). The thermal barrier (200) is formed in a folded shape that covers the upper surface and front of the high voltage terminal (120). Both sides of the thermal barrier (200) are open for the withdrawal of the bus bar (500), that is, for connecting the bus bar (500) to an adjacent battery module (100), but by covering the upper surface and front of the high voltage terminal (120), the discharge and diffusion of the ejected material are prevented as much as possible. Additionally, it may be desirable to secure the maximum coverage area by having a width of the thermal barrier (200) that corresponds to the front width of the module housing (110).

[0047] FIG. 4 is an exploded perspective view illustrating the mounting structure of a thermal barrier (200), and FIG. 5 is a drawing illustrating a battery module (100) with a thermal barrier (200) mounted thereon. A module lifting rib (130) having a module lifting hole (132) formed therein forms a space open to the front of the module housing (110). By utilizing this space, a fastening member (300) can be easily installed even if the front and top surfaces are blocked by a folded thermal barrier (200).

[0048] Referring to FIG. 4, the fastening member (300) includes a nut (310) inserted into the interior of the module lifting rib (130), a washer (312) placed on the upper surface of the module lifting rib (130), and a bolt (314) that passes through the fastening hole (210) and washer (312) of the thermal barrier (200) and the module lifting hole (132) and screws into the nut (310).

[0049] Here, it is preferable that the nut (310) be installed inside the module lifting rib (130) in a structure that does not rotate together with the rotation of the bolt (314). For example, the nut (310) may be a square nut, and as the nut (310) is installed semi-fixed inside the module lifting rib (130), the torque of the bolt (314) is fully transferred to the screw fastening of the nut (310). Due to this fastening structure, the fastening member (300) can be easily installed even if the module lifting hole (132) is blocked by the thermal barrier (200). For reference, as shown in FIG. 4, the nut (310) may also be a square nut.

[0050] Alternatively, to reduce costs and improve the process by reducing the number of parts of the fastening member (300), the fastening member (300) may be configured with a rivet (320) that is installed through the fastening hole (210) and the module lifting hole (132) (see FIG. 10). For example, a nail-shaped rivet (320) can be inserted into the fastening hole (210) and the module lifting hole (132), and then the rivet fastening can be completed using a rivet gun. However, unlike bolts (314) and nuts (310), rivet fastening has the disadvantage that repeated fastening and disassembly are impossible, so it is desirable to select an appropriate fastening member (300) considering the need for disassembly, etc.

[0051] In addition, to ensure additional assembly rigidity of the thermal barrier (200), a heat-resistant silicone (330) is applied to the contact surface between the thermal barrier (200) and the module housing (110), after which a fastening member (300) can be attached (see FIG. 10). By combining the adhesive force of the heat-resistant silicone (330) and the fastening force of the fastening member (300), the thermal barrier (200) is very firmly fixed to the module housing (110).

[0053] [Second embodiment]

[0054] A second embodiment of the present invention includes a busbar cover (400) for protecting a busbar (500). Referring to FIG. 1, the fronts of eight battery modules (100) are arranged to face toward a center frame (14) that crosses the center of the pack case (12), and accordingly, a thermal barrier (200) is positioned adjacent to the center frame (14).

[0055] As described above, since both sides of the thermal barrier (200) are open for connecting the busbar (500), the ejection from the battery module (100) that has undergone thermal runaway is effectively blocked to the battery module (100) beyond the center frame (14), but the blocking effect is reduced for the battery modules (100) connected in a row by the thermal barrier (200). The high-voltage terminal (120) and the busbar (500) of the adjacent battery module (100) are susceptible to damage from the high-temperature ejection, and there is also concern about heat propagation due to the accumulation of the ejection.

[0056] The second embodiment of the present invention enables more effective prevention of heat propagation by protecting the high-voltage terminal (120) and the busbar (500) of the battery module (100) with a flame-retardant cover. FIG. 6 is a drawing showing a busbar cover (400) provided in the second embodiment of the present invention, and FIG. 7 is a drawing showing a structure in which the busbar cover (400) is mounted on the battery module (100).

[0057] Referring to the drawing, the battery module (100) includes a busbar (500) and a busbar cover (400) that encloses the entire busbar (500), and both ends of the busbar (500) protected by the busbar cover (400) are each mechanically fixed to high-voltage terminals (120) of adjacent module housings (110) and electrically connected to each other.

[0058] Here, the busbar cover (400) is composed of two pieces: a lower busbar cover (410) and a upper busbar cover (420). The lower busbar cover (410) is a lower structure that supports and supports the bottom surface of the busbar (500) and is provided with a connection hole (412) that exposes the busbar (500) to the high-voltage terminal (120) of the module housing (110). The upper busbar cover (420) is an upper structure that encloses the busbar (500) by combining with the lower busbar cover (410) and is provided with a cover fastening hole (422) corresponding to the module lifting hole (132).

[0059] Since the busbar cover (400) has a structure that encloses the entire busbar (500), the busbar (500) is placed on the lower busbar cover (410), the busbar (500) is fixed to the high-voltage terminal (120) through the connection hole (412) of the lower busbar cover (410), and then the upper busbar cover (420) is attached to assemble the busbar (500) into the module housing (110). In this regard, it may be desirable in terms of assembly to configure the lower busbar cover (410) and the upper busbar cover (420) so that they can be joined together in a one-touch manner using a hook (414) structure.

[0060] FIG. 8 is a drawing illustrating a battery module (100) including a thermal barrier (200) and a busbar cover (400), and FIG. 9 is a cross-sectional view taken along the line "AA" in FIG. 8. The busbar cover (400) is attached to one of a pair of high-voltage terminals (120) and is extended to a length that can be connected to the high-voltage terminal (120) of an adjacent battery module (100). Then, the thermal barrier (200) is attached over the busbar cover (400) to wrap around it. By this double cover of the high-voltage terminals (120), the external discharge of the ejected material from the battery module (100) where thermal runaway has occurred is further prevented, and the inflow of the ejected material to the adjacent battery module (100) is further suppressed.

[0061] In addition, in the second embodiment, the busbar cover (400) and the thermal barrier (200) are fixed simultaneously. In other words, both the busbar cover (400) and the thermal barrier (200) are fixed together to the same module lifting hole (132) of the module housing (110). Referring to FIG. 9, the fastening member (300) is fastened to the module lifting hole (132) by penetrating the fastening hole (210) of the thermal barrier (200) and the cover fastening hole (422) of the busbar cover (400). Since the busbar cover (400) and the thermal barrier (200) can be fixed at once with a single fastening member (300), the assembly processability is improved and the number of parts is reduced, which helps to improve costs.

[0062] In addition, the busbar cover (400) has the storage space of the busbar (500) and the fixing part of the busbar cover (400) separated from each other. That is, the cover fastening hole (422) of the busbar upper cover (420) is not connected to the storage space of the busbar (500), and accordingly, the sealing of the high voltage terminal (120) is ensured.

[0063] The fastening member (300) in the second embodiment, as in the first embodiment, may be a nut (310) inserted into the interior of the module lifting rib (130), a bolt (314) that is screwed into the nut (310) by passing through the fastening hole (210), the cover fastening hole (422), and the module lifting hole (132), or a rivet (320) installed by passing through the fastening hole (210), the cover fastening hole (422), and the module lifting hole (132). However, since the busbar upper cover (420) is interposed between the thermal barrier (200) and the module lifting hole (132), there is little need to additionally place a washer (312) to prevent screw loosening. In addition, to secure additional assembly rigidity of the thermal barrier (200), heat-resistant silicone (330) may also be applied to the contact surface between the thermal barrier (200) and the module housing (110).

[0064] FIG. 10 is a drawing illustrating another embodiment of the thermal barrier (200). For reference, FIG. 10 shows a rivet (320) which is a fastening member (300) and heat-resistant silicone (330) for securing additional assembly rigidity. Also, the thermal barrier (200) illustrated in FIG. 7 to FIG. 10 has a concave stepped surface (220) formed around the fastening hole (210). The stepped surface (220) of the thermal barrier (200) can be formed to a size corresponding to the step formed by the module lifting rib (130) with respect to the upper surface of the module housing (110). Due to this stepped surface (220) of the thermal barrier (200), the gap between the thermal barrier (200) and the high-voltage terminal (120) is reduced, thereby improving the protective effect around the high-voltage terminal (120).

[0066] The present invention has been described in more detail above through drawings and embodiments. However, the configurations described in the drawings or embodiments described in this specification are merely one embodiment of the present invention and do not represent all technical concepts of the present invention; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application. Explanation of the symbols

[0067] 10: Battery pack 12: Pack case 14: Center frame 100: Battery module 110: Module housing 120: High voltage terminal 130: Module lifting rib 132: Module lifting hole 200: Thermal barrier 210: Fastening hole 220: Step surface 300: Fastening member 310: Nut 312: Washer 314: Bolt 320: Rivet 330: Heat-resistant silicone 400: Busbar cover 410: Busbar lower cover 412: Connection hole 414: Hook 420: Busbar upper cover 422: Cover fastening hole 500: Busbar

Claims

Claim 1 A module housing accommodating multiple battery cells; a pair of high-voltage terminals provided on the front of the module housing; a pair of module lifting holes provided between the high-voltage terminals; a thermal barrier covering a portion of the front of the module housing including the high-voltage terminals, with fastening holes formed through its upper surface; A battery module comprising: a fastening member installed through the module lifting hole and the fastening hole to fix the thermal barrier to the module lifting hole; wherein the module lifting hole is formed on the upper surface of a module lifting rib that forms a space open to the front of the module housing while having a step difference with respect to the upper surface of the module housing; wherein the thermal barrier has a folded shape that wraps around the upper surface and front of the high voltage terminal; and further comprises a busbar and a busbar cover that wraps the busbar, wherein both ends of the busbar are each mechanically fixed to the high voltage terminal of an adjacent module housing and electrically connected to each other, and the busbar cover comprises: a lower busbar cover having connection holes at both ends on which the entire busbar is seated and which expose the busbar to the high voltage terminal; and a busbar upper cover that wraps the busbar by being combined with the lower busbar cover and has a cover fastening hole corresponding to the module lifting hole, wherein the cover fastening hole is spaced apart from the lower busbar cover. Claim 2 delete Claim 3 delete Claim 4 A battery module according to claim 1, characterized in that the width of the thermal barrier corresponds to the front width of the module housing. Claim 5 A battery module according to claim 1, wherein the fastening member comprises a nut inserted into the interior of the module lifting rib, a washer disposed on the upper surface of the module lifting rib, a fastening hole and a washer, and a bolt that penetrates the module lifting hole and screws into the nut. Claim 6 A battery module according to claim 5, characterized in that the nut is installed inside the module lifting rib so as not to rotate together with the rotation of the bolt. Claim 7 A battery module according to claim 1, characterized in that the fastening member is a rivet installed through the fastening hole and the module lifting hole. Claim 8 A battery module according to claim 1, characterized in that heat-resistant silicone is applied to the contact surface between the thermal barrier and the module housing. Claim 9 delete Claim 10 delete Claim 11 A battery module according to claim 1, characterized in that the busbar lower cover and the busbar upper cover are mutually coupled by a hook structure. Claim 12 A battery module according to claim 1, wherein the thermal barrier surrounds the busbar cover. Claim 13 A battery module according to claim 12, wherein the fastening member is fastened to the module lifting hole by penetrating the fastening hole of the thermal barrier and the cover fastening hole of the busbar cover. Claim 14 A battery module according to claim 13, wherein the fastening member is a nut inserted into the interior of the module lifting rib, and a bolt that is screwed onto the nut by penetrating the fastening hole, the cover fastening hole, and the module lifting hole, or a rivet installed by penetrating the fastening hole, the cover fastening hole, and the module lifting hole. Claim 15 A battery module according to claim 1, characterized in that a concave stepped surface corresponding to the step formed by the module lifting rib with respect to the upper surface of the module housing is formed around the fastening hole of the thermal barrier.

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