Busbar assembly including firewall and battery pack including 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 based on Korean Patent Application No. 10-2022-0127380, filed 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 firewall 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 the 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-power devices. In order to supply high-capacity and high-power 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. Compared to cables, 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.

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

[0006] FIG. 1 is a perspective view showing a conventional busbar before and after it has been damaged by a 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 bus bar body 110, and the portion of the bus bar 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 surrounding battery cells, which can spread the fire. If a fire in a battery cell damages the silicone tube 130 of the bus bar connecting the battery modules, the insulating tape 120 may expand, exposing the bus bar body 110 inside.

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

[0011] Patent Document 1 discloses a bus bar including a metal bar made 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 the metal bar does not come into direct contact with surrounding metal objects, preventing short circuits.

[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 the surface of the busbar body in an intermediate portion 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 with fine voids inside, and the expandable graphite functions as a heat insulator. This prevents the insulating member from being exposed to high-temperature gas, thereby preventing thermal damage to the insulating member and exposure of the busbar body.

[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, a gap may form between the busbar body and the heat-resistant member, or if the expandable graphite is ceramified and a gap forms, the busbar body may be exposed. Therefore, these can only be used as a limited safety measure against fire.

[0016] Therefore, there is a need for a more robust technology 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] Japanese 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 an object of the present invention is to provide a busbar assembly that can delay the penetration of flames between the busbar body and the heat-resistant member when the busbar assembly is exposed to high temperatures, thereby delaying the ceramicization of the heat-resistant member. [Means for solving the problem]

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

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

[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 a temperature of at least 1,200°C or higher.

[0027] The outer 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 member may be at least one of a bolt and nut, a bolt, a pin, and a rivet.

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

[0031] The battery pack may include a battery pack housing that accommodates two or more battery modules, a pack frame that arranges 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 various combinations of means for solving the above problems. [Effects 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 firewall 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, and therefore 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, the busbar body is minimally exposed to the outside, thereby reducing the risk of a short circuit. [Brief explanation of the drawings]

[0036] [Figure 1]1A and 1B are perspective views showing a conventional bus bar before and after it has been damaged by fire. [Figure 2] FIG. 1 is a perspective view of a busbar assembly according to the present invention. [Figure 3] 1 is a vertical cross-sectional view of a busbar assembly according to the present invention; [Figure 4] 10A to 10C are vertical cross-sectional views illustrating 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. [Figure 5] 1 is a perspective view of a battery pack including a bus bar assembly according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0037] Hereinafter, with reference to the accompanying drawings, a detailed description will be given of an embodiment of the present invention that will enable a person of ordinary skill in the art to easily carry out the present invention. However, in 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] Furthermore, 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 a direct connection but also an indirect connection via another element therebetween. Furthermore, unless otherwise specified, "including a certain element" does not mean that other elements are excluded, but that other elements may also be included.

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

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

[0041] Furthermore, throughout the description of the present invention and the claims, unless otherwise specified, "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 thereof, a firewall 220 coupled to the outer surface of the busbar body 210 adjacent to the electrical connection portions, and a heat-resistant member 230 that encloses the firewall 220 and surrounds the outer surface of the busbar body 210 excluding 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 can 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 can be determined in consideration of the amount of current to be passed and resistance.

[0047] Although the drawings of the present invention all show a straight line, the shape of the busbar body can be manufactured taking into consideration the position of the connector of the electrical component or battery module to be electrically connected, and therefore, it 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 a V shape bent at both ends 90 degrees on the plane, etc. The busbar can also be branched in the middle of the busbar body to have two or more electrical connections.

[0048] Firewalls 220 are coupled to a first surface of busbar body 210 and a second surface opposite the first surface. Firewall 220 is located between busbar body 210 and heat-resistant member 230 at the end of heat-resistant member 230. Although heat-resistant member 230 is shown in FIGS. 2 to 4 as completely surrounding firewall 220, it may be located only inside firewalls 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, or an alloy 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 separated 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 firewall 220 is coupled, and may be formed of, for example, a heat-shrinkable tube. 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 insulation state. However, if the heat-resistant member 230 is made of a material that ceramicizes at high temperatures, cracks caused by the ceramicization may expose the busbar body 210 inside, potentially causing a short circuit.

[0056] Referring to FIG. 3, the portions at both ends of the heat-resistant member 230 where the busbar body 210 and the heat-resistant member 230 come into contact are the portions most at 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 preventing flames from penetrating between the heat-resistant member 230 and the busbar body 210.

[0058] In this way, the firewall 220 and the heat-resistant member 230 provided between the firewalls 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 ceramizing at high temperatures, for example, at least 1,200° C. or higher, and more particularly, 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 can become ceramic and crack.

[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 gases and flames 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 bus bar body 110 in the related art, the problem of the silicon tube 130 disappearing and the bus bar body being exposed can be prevented.

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

[0065] Referring to FIG. 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 alternately.

[0067] 2 shows a structure in which slits are formed in firewall 220 on the first surface, which is the top surface of busbar body 210, but a firewall 220 of the same shape as firewall 220 attached to the first surface can also be attached to the 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 slits are formed by removing parts of the outer surface on the side attached to busbar body 210 and the opposite side.

[0068] By forming the outer surface of the firewall 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 recessed portion 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, two or more through holes may be formed at each end of the busbar body.

[0071] For example, the busbar assembly may be coupled to the connectors of the battery modules to electrically connect the battery modules installed inside the 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 performing a bolting operation using bolts and nuts to connect to the battery module connectors, the busbar assembly may be coupled to the first and second battery modules by inserting bolts into the through-holes 211 and then fastening them with nuts.

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

[0073] FIG. 4 is a vertical cross-sectional view illustrating 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 breaks out on the left side of the busbar assembly, the high heat causes the portion of heat-resistant member 230 adjacent to the fire to melt and begin to disappear. If heat-resistant member 230 is gradually removed and even the 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 spreading further to the right side of the busbar assembly.

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

[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 bus bar assembly 200 that electrically connects the battery modules 301, wherein the bus bar assembly 200 is 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 bus bar body 210 that do not include the heat-resistant member 230 are coupled to connectors of the battery modules 301.

[0078] In this way, 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 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 fire to break out, the firewall coupled to the outer surface of the busbar body 210 can block the movement of the flames, thereby delaying the ceramicization of the heat-resistant member 230 and maintaining the insulation state of the busbar body.

[0080] Meanwhile, unlike the example shown in FIG. 5 , even if the bus bar assembly is arranged not on the top surface of pack frame 310 but in another location in the battery pack so as to come into contact with a component made of an electrically conductive metal material, insulation can be maintained 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 be able to make various applications and modifications within the scope of the present invention 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 packs 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 encloses the firewall and surrounds the outer surface of the bus bar body except for the electrical connection portion; Including, The outer surface of the firewall has a structure in which slits are formed.

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

3. 2. The busbar assembly of claim 1, wherein the firewall is located at a distal end of the heat-resistant member.

4. 10. 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 according to claim 7 , wherein the heat-resistant member ceramizes at a temperature of at least 1,200° C. or higher.

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

10. The busbar assembly according to claim 9 , wherein the fastening member is at least one of a bolt and nut, a bolt, a pin, and a rivet.

11. a battery pack housing that houses two or more battery modules; a pack frame in which the battery modules are arranged in a space partitioned therein for fixing the positions of the battery modules; a busbar assembly according to any one of claims 1 to 10, which electrically connects the battery modules; Including the battery pack.

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