Busbar assembly including a firewall and battery pack including the same

Abstract

The present invention relates to a busbar assembly including a busbar body having electrical connection portions formed on both ends, a fire wall coupled to an outer surface of the busbar body adjacent to the electrical connection portions, and a heat-resistant member enclosing the fire wall and surrounding the outer surface of the busbar body excluding the electrical connection portions, and the safety of the busbar assembly is improved by delaying the penetration of flames between the heat-resistant member and the busbar body.

Description

[Technical field]

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0127380 filed on October 5, 2022, and all contents disclosed in the Korean Patent Application are incorporated herein by reference.

[0002] The present invention relates to a busbar assembly including a fire barrier and a battery pack including the same, and more particularly, to a busbar assembly and a battery pack including the same that can delay ceramicization of the heat-resistant member surrounding the busbar body by preventing flames from entering between the busbar body and a heat-resistant member in the event of a fire. [Background technology]

[0003] The number of devices using lithium secondary batteries as an energy source is increasing, and lithium secondary batteries are being applied to high-capacity and high-output devices. In order to supply high-capacity and high-output energy, the use of battery modules in which a number of battery cells are electrically connected and battery packs in which the battery modules are connected in series and / or parallel is also increasing.

[0004] In the battery modules and battery packs, bus bars are widely used as a means for electrically connecting battery cells and battery modules. The bus bars are suitable for use as a large current carrying means because they can stably carry a large amount of current even with a relatively small diameter compared to cables.

[0005] The busbar has a busbar body made of copper and / or aluminum, which have excellent electrical conductivity, disposed on the inside, electrical connection parts for forming an electrical connection disposed on both ends of the busbar body, and the remaining part except for the electrical connection parts is covered with a tube or extrusion to ensure electrical insulation.

[0006] FIG. 1 is a perspective view showing a conventional busbar before and after it has been damaged by fire.

[0007] Referring to FIG. 1, a conventional busbar includes a busbar body 110 made of an electrically conductive material, an insulating tape 120 surrounding the remaining portion of the outer surface of the busbar body 110 except for both ends, and a silicone tube 130 provided on the outer surface of the insulating tape 120.

[0008] The insulating tape 120 and the silicone tube 130 ensure electrical insulation of the busbar body 110, and the portion of the busbar body 110 that is not provided with the insulating tape 120 and the silicone tube 130 can be physically connected to other devices and function as an electrical connection path.

[0009] When a battery cell ignites or explodes, the generated heat energy is transferred to the surrounding battery cells, and the fire may spread. If the silicone tube 130 of the bus bar connecting the battery modules is damaged by a fire in the battery cell, the insulating tape 120 may spread, exposing the bus bar body 110 inside.

[0010] The exposed busbar body may come into contact with other battery pack structures and cause a short circuit. Such an internal short circuit may form an electrical closed circuit inside the battery pack, which may accelerate the thermal runaway phenomenon inside the battery pack.

[0011] Patent document 1 discloses a bus bar including a metal bar formed of a metal material, a bandage member surrounding the remaining portion of the metal bar except for both ends, and an insulating tube surrounding both the metal bar and the bandage member.

[0012] In Patent Document 1, the bandage material on the surface of the metal bar remains attached to the surface of the metal bar even in the event of a fire, so that the metal bar does not come into direct contact with surrounding metal objects and short circuits can be prevented.

[0013] Patent Document 2 discloses a busbar including a busbar body made of a conductive metal and having two terminals formed thereon, an insulating member covering a surface of a middle portion of the busbar body between the two terminals, and an expandable graphite layer containing thermally expandable graphite formed on the surface of the insulating member.

[0014] In the busbar of Patent Document 2, when the expandable graphite expands, it becomes a porous or foamed structure having fine gaps therein, and the expandable graphite functions as a heat insulating material, thereby preventing the insulating member from being exposed to high-temperature gas, and thus preventing the insulating member from being thermally damaged and the busbar body from being exposed.

[0015] Patent Document 1 ensures safety by preventing the metal bar from coming into direct contact with a metal object in a high-temperature environment, while Patent Document 2 ensures safety by preventing the busbar body from being exposed to a high-temperature environment. Even if the busbar is surrounded by a heat-resistant member or expandable graphite, if these are separated from the busbar body and a gap occurs between the busbar body and the heat-resistant member, or if the expandable graphite is turned into ceramic and a gap occurs, the busbar body may be exposed, so these can only be used as a limited safety measure against fire.

[0016] Therefore, a more robust technique is needed that can ensure safety by delaying exposure of the busbar body to the maximum extent possible. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Korean Patent Publication No. 10-2021-0141095 [Patent Document 2] Patent Publication No. 2022-094702 Summary of the Invention [Problem to be solved by the invention]

[0018] The present invention has been made to solve the above problems, and has an object to provide a busbar assembly that can delay the penetration of flames between a busbar body and a heat-resistant member when the busbar assembly is exposed to high temperatures, thereby delaying the ceramification of the heat-resistant member. [Means for solving the problem]

[0019] To achieve the above object, a busbar assembly according to the present invention may include a busbar body having electrical connection portions formed on both ends thereof, a fire wall coupled to an outer surface of the busbar body adjacent to the electrical connection portions, and a heat-resistant member enclosing the fire wall and surrounding an outer surface of the busbar body excluding the electrical connection portions.

[0020] The firewall may be coupled to a first side of the busbar body and a second side opposite the first side.

[0021] The firewall may be located at a distal end of the heat resistant member.

[0022] The firewall may be made of the same material as the busbar body.

[0023] The firewall may be made of any one or more materials selected from the group consisting of aluminum, copper, nickel, and alloys thereof.

[0024] The firewall may be joined to the busbar body by laser welding.

[0025] The heat-resistant member may include one or more selected from the group consisting of high heat-resistant silicone, polyphenylene sulfide, polyether ether ketone, polyphthalamide, polyamide, polysulfone, polyethersulfone, polyetherimide, acrylic fiber, and polybenzimidazole.

[0026] The heat-resistant member can be ceramified at least at 1,200° C. or higher.

[0027] The exterior surface of the firewall may have a slit structure.

[0028] The electrical connection portion may include a through hole for fastening a coupling member.

[0029] The fastening members may be at least one of a bolt and a nut, a bolt, a pin, and a rivet.

[0030] The present invention provides a battery pack including the busbar assembly.

[0031] The battery pack may include a battery pack housing that accommodates two or more battery modules, a pack frame that disposes the battery modules in a space partitioned therein to fix the positions of the battery modules, and a bus bar assembly that electrically connects the battery modules.

[0032] Furthermore, the present invention can also be provided in the form of a combination of various means for solving the above problems. Effect of the Invention

[0033] As described above, in the bus bar assembly according to the present invention, even if a portion of the heat-resistant member is damaged when exposed to high temperatures, the fire wall can prevent flames from penetrating to the center of the heat-resistant member.

[0034] In this way, the time it takes for the heat-resistant member to become ceramic at high temperatures can be delayed, so that the penetration of flames through cracks that occur in the ceramicized portion of the heat-resistant member can be delayed.

[0035] Therefore, in the event of a fire, exposure of the busbar body to the outside can be minimized, thereby reducing the risk of a short circuit. [Brief description of the drawings]

[0036] [Figure 1]1 is a perspective view showing a conventional bus bar before and after it is damaged by fire; [Diagram 2] FIG. 2 is a perspective view of a busbar assembly according to the present invention; [Diagram 3] FIG. 2 is a vertical cross-sectional view of a busbar assembly according to the present invention. [Figure 4] 5A to 5C are vertical cross-sectional views illustrating a process of delaying the inflow of flames between a busbar body and a heat-resistant member when the busbar assembly according to the present invention is exposed to flames. [Diagram 5] FIG. 2 is a perspective view of a battery pack including a bus bar assembly according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, in which a person having ordinary skill in the art to which the present invention pertains can easily carry out the present invention. However, when describing the operation principle of the preferred embodiment of the present invention in detail, detailed description of related well-known functions or configurations will be omitted if it is determined that such detailed description may unnecessarily obscure the gist of the present invention.

[0038] In addition, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only the case where the part is directly connected to another part, but also the case where the part is indirectly connected via another element between the two parts. In addition, when a part includes a certain component, it does not mean that the other component is excluded, but that the part may further include the other component, unless otherwise specified.

[0039] Furthermore, descriptions that specify or limit components are applicable to all inventions and are not limited to a particular invention unless otherwise specified.

[0040] Furthermore, throughout the description of the present invention and the claims, the singular includes the plural unless otherwise stated.

[0041] In addition, throughout the description of the present invention and the claims, unless otherwise stated, "or" includes "and." Therefore, "including A or B" means three cases: including A, including B, or including both A and B.

[0042] The invention will now be explained with reference to the drawings and in conjunction with detailed embodiments.

[0043] FIG. 2 is a perspective view of a busbar assembly according to the present invention, and FIG. 3 is a vertical cross-sectional view of the busbar assembly according to the present invention.

[0044] 2 and 3, a busbar assembly 200 according to the present invention includes a busbar body 210 having electrical connection portions formed on both ends, a fire wall 220 coupled to an outer surface of the busbar body 210 adjacent to the electrical connection portions, and a heat-resistant member 230 that encloses the fire wall 220 and surrounds the outer surface of the busbar body 210 except for the electrical connection portions.

[0045] The bus bar assembly 200 includes an inter-module bus bar for connecting battery modules arranged in a battery pack as a means for electrically connecting electrical components spaced apart from each other.

[0046] In a busbar assembly, the length of the busbar body may be determined in consideration of the distance between electrical components or battery modules to be electrically connected, and the width and thickness of the busbar body may be determined in consideration of the amount of current to be passed and resistance.

[0047] Although the drawings of the present invention are all shown as straight lines, the shape of the busbar body can be manufactured taking into consideration the positions of the connectors of the electrical components or battery modules to be electrically connected, and therefore the busbar body can be configured in various shapes such as a shape bent upward or downward, an L shape bent 90 degrees on the plane of the busbar body, a U shape or V shape bent at both ends on the plane, etc. The busbar may also be branched in the middle of the busbar body to have two or more electrical connection parts.

[0048] A fire barrier 220 is coupled to a first surface of the busbar body 210 and a second surface opposite to the first surface. In addition, the fire barrier 220 is located between the busbar body 210 and the heat-resistant member 230 at an end portion of the heat-resistant member 230. Although the heat-resistant member 230 is shown to completely surround the fire barrier 220 in FIGS. 2 to 4, it may be located only inside the fire barriers 220 at both ends.

[0049] The busbar body 210 is made of a metal material having excellent electrical conductivity, such as aluminum, nickel, copper, gold, silver, tin, zinc, and alloys thereof.

[0050] Alternatively, the firewall 220 may be made of the same material as the busbar body 210 .

[0051] Specifically, the firewall 220 may be made of one or more materials selected from the group consisting of aluminum, nickel, copper, gold, silver, tin, zinc, and alloys thereof.

[0052] The firewall 220 may be a separate component separate from the busbar body 210 and joined to the busbar body 210 by laser welding, or may be integrally formed when the busbar is manufactured.

[0053] The heat-resistant member 230 may include one or more selected from the group consisting of high heat-resistant silicone, polyphenylene sulfide, polyether ether ketone, polyphthalamide, polyamide, polysulfone, polyethersulfone, polyetherimide, acrylic fiber, and polybenzimidazole.

[0054] The heat-resistant member 230 is provided to surround the outer surface of the busbar body 210 to which the fire barrier 220 is coupled, and may be formed of, for example, a tube having heat shrinkability. A heat-resistant tube may be further provided to further surround the outer surface of the heat-resistant member 230.

[0055] The heat-resistant member 230 can prevent the busbar body 210 and the firewall 220 from being exposed and maintain their insulating state. However, if the heat-resistant member 230 is made of a material that is converted into a ceramic at high temperatures, cracks caused by the conversion into a ceramic may expose the busbar body 210 inside, which may cause a short circuit.

[0056] Referring to FIG. 3, both ends of heat-resistant member 230 where busbar body 210 and heat-resistant member 230 come into contact are at the highest risk of flame penetration.

[0057] Therefore, in the present invention, in the event of a fire, in order to prevent flames from penetrating between the heat-resistant member 230 and the busbar body 210, a fire barrier 220 is attached adjacent to the end of the heat-resistant member 230, thereby making it possible to prevent flames from penetrating between the heat-resistant member 230 and the busbar body 210.

[0058] In this manner, the fire barriers 220 and the heat-resistant member 230 provided between the fire barriers 220 can prevent the flame from spreading, thereby delaying the time it takes for the center of the heat-resistant member 230 to become ceramic and reducing the risk of the busbar body 210 being exposed, thereby providing a busbar assembly with improved safety.

[0059] The center of the heat-resistant member means the center of the heat-resistant member parallel to the y direction in FIG.

[0060] The heat-resistant member 230 may be a material that has the property of being ceramified at high temperatures, for example, at least at 1,200° C. or higher, and more particularly at 1,500° C. or higher.

[0061] Therefore, the heat-resistant material can maintain its shape and exhibit flame resistance at temperatures below 1,200°C. However, at temperatures above 1,200°C, it becomes ceramic and cracks may occur.

[0062] If a battery cell in the battery pack ignites or explodes and heat is transferred to the bus bar connected to the battery module, the heat-resistant member will be ceramicized by the gas and flame released from the battery cell but will be able to maintain its shape.

[0063] Therefore, as shown in FIG. 1, when the silicon tube 130 is provided on the outer surface of the busbar body 110 in the related art, the problem of the silicon tube 130 disappearing and exposing the busbar body can be prevented.

[0064] In one embodiment, the exterior surface of the firewall may have a slit structure.

[0065] 2, the firewall 220 has a structure in which a portion of the busbar body 210 is removed to form a slit on the side opposite to the outer surface of the firewall 220 coupled to the busbar body 210.

[0066] Alternatively, instead of the slits, recesses and protrusions may be formed in a repeated pattern.

[0067] 2 shows a structure in which slits are formed in firewall 220 on a first surface, which is the top surface of busbar body 210, a firewall 220 of the same shape as firewall 220 attached to the first surface may also be attached to a second surface, which is the bottom surface of busbar body 210. Firewall 220 attached to the second surface is attached symmetrically to firewall 220 attached to the first surface with respect to busbar body 210, so that firewall 220 has a structure in which a part of the outer surface on the side attached to busbar body 210 and a part of the opposite side are removed to form slits.

[0068] In this manner, by forming the outer surface of the fire wall 220 unevenly, the surface area can be increased, so that the heat-resistant member 230 can be stably fixed.

[0069] Furthermore, when the firewall is joined to the busbar body by laser welding, the recesses can be used to easily ensure the joining strength by welding.

[0070] The electrical connection portion includes a through hole 211 for fastening a coupling member. Although Fig. 2 shows an embodiment in which one through hole 211 is formed at each end of the busbar body 210, the number of through holes may be two or more at each end of the busbar body.

[0071] For example, the busbar assembly may be coupled to a connector of a battery module for electrical connection between a plurality of battery modules mounted inside a battery pack. One of the through holes 211 formed at both ends of the busbar assembly may be coupled to the connector of a first battery module, and the other through hole may be coupled to the connector of a second battery module. When a bolting operation using bolts and nuts is performed for connection to the battery module connectors, the busbar assembly may be coupled to the first and second battery modules by inserting a bolt into the through hole 211 and then fixing it with a nut.

[0072] Alternatively, a pin including a locking portion can be inserted into the through hole 211 to fix the bus bar assembly and the battery module connector, or a rivet can be fastened into the through hole 211 to fix the bus bar assembly and the battery module connector.

[0073] FIG. 4 is a vertical sectional view showing a process of delaying the intrusion of flames between the busbar body and the heat-resistant member when the busbar assembly according to the present invention is exposed to flames.

[0074] 4, when a fire occurs on the left side of the busbar assembly, the high heat causes a portion of heat-resistant member 230 adjacent to the fire to melt and begin to disappear. When heat-resistant member 230 is gradually removed and even heat-resistant member 230 provided on the outer surface of firewall 220 disappears, firewall 220 can prevent the flame from penetrating, thereby preventing the flame from moving further to the right side of the busbar assembly.

[0075] Therefore, the heat-resistant member 230 on the right side of the fire wall 220 adjacent to the flame can be delayed from being ceramicized.

[0076] FIG. 5 is a perspective view of a battery pack including a bus bar assembly according to the present invention.

[0077] Referring to FIG. 5 , a battery pack 300 according to the present invention includes a battery pack housing 320 that accommodates two or more battery modules 301, a pack frame 310 that arranges the battery modules 301 in a space partitioned therein to fix the positions of the battery modules 301, and a busbar assembly 200 that electrically connects the battery modules 301, the busbar assembly 200 being arranged such that a heat-resistant member 230 is located on an upper surface 311 of the pack frame 310, and electrical connection portions at both ends of the busbar body 210 that are not provided with the heat-resistant member 230 are coupled to connectors of the battery modules 301.

[0078] In this manner, even if the pack frame 310 is made of an electrically conductive metal material, the heat-resistant member 230 of the bus bar assembly 200 and the pack frame 310 are arranged to be in contact with each other, so that insulation between the bus bar assembly 200 and the pack frame 310 can be ensured when the battery pack 300 is in a normal state.

[0079] However, if flames or high-temperature gases are emitted from the battery cells constituting the battery pack 300, causing the temperature of the pack frame 310 to increase and a flame to break out, the fire barrier coupled to the outer surface of the busbar body 210 can block the movement of the flame, thereby delaying the ceramicization of the heat-resistant member 230 and maintaining the insulating state of the busbar body.

[0080] Meanwhile, unlike the configuration shown in FIG. 5 , even if the bus bar assembly is arranged not on the top surface of pack frame 310 but in another part of the battery pack so as to come into contact with a component made of an electrically conductive metal material, it is possible to maintain insulation between the bus bar assembly and the component made of an electrically conductive metal material in the event of a fire in the battery pack.

[0081] Those skilled in the art will appreciate that various applications and modifications within the scope of the present invention will be possible based on the above content. [Explanation of symbols]

[0082] 110, 210 Busbar body 120 Electrical Tape 130 Silicone tube 200 Busbar Assembly 211 Through hole 220 Fire wall 230 Heat-resistant materials 300 Battery Pack 301 Battery Module 310 Pack Frame 311 Top of pack frame 320 Battery Pack Housing

Claims

1. A busbar body having electrical connection portions formed on both ends thereof; a firewall coupled to an outer surface of the busbar body adjacent the electrical connection; a heat-resistant member that contains the fire wall and surrounds an outer surface of the bus bar body except for the electrical connection portion; The busbar assembly includes:

2. 2. The busbar assembly of claim 1, wherein the firewall is coupled to a first side of the busbar body and a second side opposite the first side.

3. The busbar assembly of claim 1 , wherein the fire barrier is located at an end of the heat resistant member.

4. 2. The busbar assembly of claim 1, wherein the firewall is made of the same material as the busbar body.

5. 2. The busbar assembly of claim 1, wherein the firewall is made of any one or more materials selected from the group consisting of aluminum, copper, nickel, and alloys thereof.

6. 10. The busbar assembly of claim 1, wherein the firewall is coupled to the busbar body by laser welding.

7. 2. The busbar assembly according to claim 1, wherein the heat-resistant member includes at least one selected from the group consisting of high heat-resistant silicone, polyphenylene sulfide, polyether ether ketone, polyphthalamide, polyamide, polysulfone, polyethersulfone, polyetherimide, acrylic fiber, and polybenzimidazole.

8. The busbar assembly of claim 7 , wherein the heat-resistant member ceramizes at least at 1,200° C. or higher.

9. 2. The busbar assembly of claim 1, wherein an outer surface of the firewall has a slit structure.

10. The busbar assembly according to claim 1 , wherein the electrical connection portion includes a through hole for fastening a coupling member.

11. The busbar assembly of claim 10 , wherein the fastening members are at least one of a bolt and a nut, a bolt, a pin, and a rivet.

12. a battery pack housing that houses two or more battery modules; a pack frame in which the battery modules are disposed in a space partitioned therein for fixing the positions of the battery modules; The busbar assembly according to any one of claims 1 to 11, which electrically connects the battery modules; Including the battery pack.

Images