Inter-module bus bar including an insulating layer and a battery pack including the same

Abstract

The present invention relates to an intermodule busbar that includes a metal plate for electrical connection, a first insulating layer that encases at least a portion of the metal plate and has high-temperature expandability, and a second insulating layer that is provided on the first insulating layer and is ceramicized at high temperature. In the event of a fire, the metal plate inside the busbar is not exposed, thereby preventing a short circuit due to contact of the metal plates.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0111786, filed on September 5, 2022, and all contents disclosed in the literature of the Korean patent application are incorporated herein by reference in their entirety.

[0002] The present invention relates to an inter-module bus bar including an insulating layer and a battery pack including the same. Specifically, the present invention relates to an inter-module bus bar capable of preventing a short circuit even when contacting a peripheral part because an insulating state is maintained even if a fire occurs inside the battery pack, and a battery pack including the same.

Background Art

[0003] There is an increasing demand for secondary batteries that can solve the problem of air pollution caused by the use of fossil fuels and store electrical energy produced by alternative energy. For example, lithium secondary batteries with high energy density per unit weight are used not only as energy sources for mobile devices such as mobile phones, tablet PCs, Bluetooth (registered trademark) earphones, and e-cigarettes, but also as energy sources for medium and large-sized devices such as electric bicycles, electric kick scooters, and electric vehicles.

[0004] As the types of devices using lithium secondary batteries as energy sources become diverse, the application of lithium secondary batteries has also expanded to devices that require high capacity and high output.

[0005] In response to such a trend, the manufacture and use of battery modules in which a large number of battery cells are electrically connected and battery packs in which the battery modules are connected in series and / or in parallel have been increasing.

[0006] On the one hand, in battery modules and battery packs, inter-module busbars are widely used as electrical connection means between battery cells and between battery modules. Since an inter-module busbar can stably conduct a large current even with a relatively small thickness compared to a cable, it is suitable for use as a large-current conduction means.

[0007] Generally, an inter-module busbar can be in a form where a metal plate containing copper or aluminum with excellent electrical conductivity is disposed inside, and the remaining portion of the outer surface of the metal plate except for both end portions of the metal plate to be joined is coated with a tube or an injection molding to ensure electrical insulation.

[0008] In this regard, FIG. 1 is a perspective view showing before and after a conventional inter-module busbar is damaged by a fire.

[0009] An inter-module busbar is used for the purpose of electrical connection between battery modules. FIG. 1 shows the structure of the inter-module busbar and the state in which the inter-module busbar is damaged by a fire.

[0010] Referring to FIG. 1, a conventional inter-module busbar includes a metal plate 110 made of an electrically conductive material, an insulating tape 120 that wraps the remaining portion of the outer surface of the metal plate 110 except for both ends, and Silicone a tube 130 provided on the outer surface of the insulating tape 120.

[0011] Since the insulating tape 120 and Silicone the tube 130 are made of an electrically insulating material, insulation can be ensured for components other than the devices coupled to both ends of the inter-module busbar.

[0012] If ignition or explosion of a battery cell inside a battery pack occurs, the thermal energy of the battery cell is transmitted to the surrounding battery cells, resulting in a fire. Due to the fire of the battery cell, the Silicone When the tube 130 is damaged, the insulating tape 120 may spread and the metal plate 110 inside may be exposed.

[0013] When the thus-exposed metal plate comes into contact with the battery pack structure, a short circuit may occur. 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.

[0014] In this regard, Patent Document 1 discloses a bus bar including a metal bar formed of a metal material, an insulating tube covering the remaining portion except both ends of the metal bar, a fireproof tape wrapping the metal bar inside the insulating tube, and a bandage member made of a fireproof material, interposed between the insulating tube and the fireproof tape, and wrapping the fireproof tape and fixed to the metal bar.

[0015] Patent Document 1 can prevent a short circuit by preventing the metal bar from directly contacting surrounding metal objects because the bandage member can firmly fix the fireproof tape even if the insulating tube disappears due to a fire.

[0016] Patent Document 2 discloses a bus bar including a metal bar formed of a metal material, a bandage member wrapping the remaining portion except both ends of the metal bar, and an insulating tube wrapping the metal bar and the bandage member together.

[0017] Patent Document 2 can prevent a short circuit because the bandage member on the surface of the metal bar maintains its attachment to the surface of the metal bar even during a fire, so that the metal bar does not directly contact surrounding metal objects.

[0018] However, since the bus bars of Patent Document 1 and Patent Document 2 further include a bandage member, the thickness and weight of the bus bar may increase.

[0019] Therefore, there is a need for a technology for an inter-module bus bar that can prevent the internal metal material from being exposed even if the insulating material provided on the outer surface of the bus bar is lost due to a fire, while minimizing the increase in volume and weight.

Prior Art Documents

Patent Documents

[0020]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0021] In order to solve the above problems, the inter-module bus bar according to the present invention is configured such that, when a fire occurs, even if the second insulating layer on the outer surface is ceramified and cracked, the metal plate inside is not exposed, thereby preventing a short circuit from occurring due to contact with surrounding metal objects.

Means for Solving the Problems

[0022] To achieve such an object, the inter-module bus bar according to the present invention can include a metal plate for electrical connection, a first insulating layer that wraps at least a part of the metal plate and has high-temperature expansibility, and a second insulating layer that is provided on the first insulating layer and ceramifies at high temperature.

[0023] The first insulating layer can include expandable flame retardant Silicone and can be included.

[0024] The second insulating layer has high heat resistance Silicone and may include one or more selected from the group consisting of polyphenylene sulfide, polyether ether ketone, polyphthalamide, polyamide, polysulfone, polyether sulfone, polyether imide, acrylic fiber, and polybenzimidazole.

[0025] The temperature at which the second insulating layer becomes ceramic can be at least 1,200°C.

[0026] When the second insulating layer becomes ceramic and cracks occur during temperature rise, the first insulating layer can expand and be inserted between the cracks to fill the space within the cracks.

[0027] When the first insulating layer expands, the metal plates inside the first insulating layer and the second insulating layer can be prevented from being exposed.

[0028] Both ends of the metal plate are not provided with the first insulating layer and the second insulating layer, and the metal plate can be exposed to form an electrical connection part.

[0029] The electrical connection part can be configured with one or more connection openings formed therein.

[0030] The present invention includes a battery pack in which battery modules are electrically connected via the inter-module bus bar.

[0031] The battery pack includes a battery pack housing that houses two or more battery modules, a pack frame in which the battery modules are arranged in a compartmentalized space inside for fixing the positions of the battery modules, and an inter-module bus bar that electrically connects the battery modules. The inter-module bus bar has a first insulating layer and a second insulating layer disposed on the upper surface of the pack frame, and the electrical connection parts at both ends where the first insulating layer and the second insulating layer are not provided can be coupled to the connectors of the battery modules.

[0032] When the second insulating layer is ceramified and the first insulating layer expands due to the temperature rise of the pack frame, the metal plate is not exposed while the inter-module bus bar is in contact with the pack frame, and the insulating state can be maintained.

[0033] The present invention can also be provided in a form in which various combinations of the means for solving the above problems are combined.

Advantages of the Invention

[0034] As described above, in the inter-module bus bar according to the present invention, even when cracks occur due to ceramification of the second insulating layer during a fire, the first insulating layer having the property of expanding at high temperature penetrates between the cracks of the second insulating layer to fill the gaps, so that it is possible to prevent the metal plate from being exposed.

[0035] Therefore, even when the state where the bus bar is in contact with the surrounding metal objects is maintained during a fire, insulation can be ensured.

Brief Description of the Drawings

[0036]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0037] Hereinafter, embodiments that enable a person having ordinary skill in the technical field to which the present invention pertains to easily implement the present invention will be described in detail with reference to the accompanying drawings. However, when explaining in detail the operating principle of a preferred embodiment of the present invention, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

[0038] Also, the same reference numerals are used for parts having similar functions and actions throughout the drawings. Throughout the specification, when a part is said to be connected to another part, this includes not only the case where they are directly connected, but also the case where they are indirectly connected with other elements interposed therebetween. Also, including a certain component means, unless otherwise stated to the contrary, it does not exclude other components, but means that other components can be further included.

[0039] Also, descriptions that limit or add components for concretization are applicable to all inventions without special limitations and are not limited to specific inventions.

[0040] Also, throughout the description and claims of the present invention, those expressed in the singular include the plural cases unless otherwise mentioned.

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

[0042] The present invention will be described together with detailed embodiments based on the drawings.

[0043] The inter-module bus bar according to the present invention is a kind of bus bar used as an electrical connection means, and refers to a means for connecting battery modules arranged in a battery pack.

[0044] Therefore, the length of the inter-module bus bar can be determined considering the distance between the battery modules to be connected, and the width and thickness thereof can be determined considering the amount of current to be conducted and the resistance.

[0045] In addition, the form of the inter-module bus bar can be determined considering the position of the connector of the battery module, and it can be configured in various forms such as a form bent upward or downward in parallel with the full width, an L-shape bent 90 degrees on a plane, a "C" shape bent 90 degrees on a plane at both ends, and a " TIFF0007712030000001.tif23" shape.

[0046] Generally, since each of both ends of the inter-module bus bar is used as a connection part for connecting to an external device, it will have a structure for connection such as fastening holes for bolt fastening being formed.

[0047] FIG. 2 is a plan view and a vertical cross-sectional view of an inter-module bus bar according to the present invention, and a cross-section along line A-A in the plan view at the upper part of FIG. 2 is shown as a vertical cross-sectional view at the lower part of FIG. 2.

[0048] Referring to FIG. 2, the inter-module bus bar 200 includes a metal plate 210 for electrical connection, a first insulating layer 220 that wraps at least a part of the metal plate 210 and has high-temperature expansibility, and a second insulating layer 230 provided on the first insulating layer 220 and ceramifying at high temperature.

[0049] Both ends of the metal plate 210 are not provided with the first insulating layer 220 and the second insulating layer 230, and the metal plate 210 is exposed to form an electrical connection part 240.

[0050] The electrical connection part 240 is in a form in which one or more connection openings 241 are formed.

[0051] Either one of the electrical connection parts 240 formed at both ends of the inter-module bus bar 200 can be connected to the positive electrode connector of the first battery module, and the other can be connected to the negative electrode connector of the second battery module. Specifically, when performing a bolting operation using bolts and nuts for connection to the connectors of the battery modules, after inserting the bolts into the openings 241, the inter-module bus bar 200 can be connected to the first battery module and the second battery module by fixing them with nuts.

[0052] Since the second insulating layer 230 constitutes the outermost outer surface that is directly contacted by the flame in the event of a fire, it has high heat resistance Silicone and can include one or more selected from the group consisting of polyphenylene sulfide, polyether ether ketone, polyphthalamide, polyamide, polysulfone, polyether sulfone, polyether imide, acrylic fiber, and polybenzimidazole.

[0053] Specifically, the second insulating layer 230 has high heat resistance such that when exposed to a flame or high-temperature gas, small cracks occur while it is being ceramized. Silicone It can be.

[0054] The high heat resistance Silicone exhibits the performance of a normal Silicone resin at normal temperature, but at high temperature, it is converted into a ceramized structure and has ceramic properties, so it has impact resistance while maintaining a certain strength.

[0055] The second insulating layer 230 can be a substance having the property of being ceramized at high temperature. For example, it can be ceramized at a minimum of 1,200 °C or higher.

[0056] Therefore, below 1,200 °C, the second insulating layer can maintain its form and exhibit heat resistance performance against flames. However, above 1,200 °C, it may be ceramized and cracks may occur.

[0057] When ignition and explosion occur in the battery cells within the battery pack and heat is transferred to the inter-module bus bar coupled to the battery module, the second insulating layer ceramicizes due to the gas and flame released from the battery cells but can maintain its form.

[0058] Therefore, conventionally, Silicone When providing the tube on the outer surface of the metal plate, Silicone It is possible to prevent the problem that the tube disappears and the metal plate is exposed.

[0059] The first insulating layer 220 can include an expandable flame retardant having the property of expanding at high temperatures. Silicone can be included.

[0060] The thermal expansion temperature of the first insulating layer 220 may be higher than the temperature at which the second insulating layer 230 ceramicizes.

[0061] That is, when a high-temperature environment is created due to a fire, the second insulating layer ceramicizes and cracks occur. When flame or venting gas penetrates through the cracks and contacts the first insulating layer, the first insulating layer having high-temperature expansibility expands to fill the gaps of the cracks. In this way, since the metal plate is not exposed to the outside in the portion where the first insulating layer and the second insulating layer of the inter-module bus bar are provided, insulation can be ensured.

[0062] FIG. 3 is a vertical cross-sectional view showing before and after the inter-module bus bar according to the present invention is damaged by a fire.

[0063] FIG. 3 shows the process in which the inter-module bus bar is damaged by a fire in three stages, and time elapses from top to bottom.

[0064] Referring to the first figure of FIG. 3, it is a vertical cross-sectional view of the inter-module bus bar 200 in a normal state without a fire. The outer surface of the innermost metal plate 210 is sequentially wrapped by a first insulating layer 220 having high-temperature expansibility and a second insulating layer 230 that ceramifies at high temperatures.

[0065] Referring to the second figure of FIG. 3, when a fire occurs in the battery cell and flames and high-temperature gases are transmitted to the inter-module bus bar, the outermost second insulating layer 230 ceramifies, and cracks occur where the outer sides of the first insulating layer 220 and the second insulating layer 230 communicate.

[0066] Referring to the third figure of FIG. 3, when the second insulating layer 230 ceramifies and cracks occur during temperature rise, when high-temperature gases and flames are transmitted to the first insulating layer 220 through the cracks, the first insulating layer 220 expands and is inserted into the cracks to fill the space inside the cracks.

[0067] In this way, since the first insulating layer 220 expands to fill the gap of the crack generated in the second insulating layer 230, the portion of the inter-module bus bar provided with the first insulating layer 220 and the second insulating layer 230 does not communicate with the outer surface of the second insulating layer 230, and the state of being wrapped by the first insulating layer 220 and the second insulating layer 230 can be maintained.

[0068] Therefore, when the second insulating layer ceramifies and the first insulating layer expands due to a fire, the metal plate portion inside the first insulating layer and the second insulating layer is not exposed.

[0069] FIG. 4 is a perspective view of a battery pack including the inter-module bus bar of FIG. 2.

[0070] The battery pack shown in Fig. 4 is configured such that a plurality of battery modules 301 are electrically connected via the inter-module bus bar 200 according to the present invention. Although Fig. 4 shows a battery pack including nine battery modules, this is merely an example for explanation, and the arrangement form and number of battery modules constituting the battery pack, and the connection position and form of the inter-module bus bar used to connect the battery modules are not limited thereto.

[0071] Referring to Fig. 4, the battery pack 300 according to the present invention includes a battery pack housing 320 that houses two or more battery modules 301, a pack frame 310 that arranges the battery modules in a compartmentalized space inside to fix the positions of the battery modules 301, and an inter-module bus bar 200 that electrically connects the battery modules 301. The inter-module bus bar 200 is arranged such that the first insulating layer and the second insulating layer 230 are located on the upper surface 311 of the pack frame, and the electrical connection portions at both ends of the metal plate 210 without the first insulating layer and the second insulating layer 230 are coupled to the connectors of the battery modules 301.

[0072] Thus, even if the pack frame 310 is made of an electrically conductive metal material, since the second insulating layer 230 of the inter-module bus bar 200 is arranged to contact the pack frame 310, insulation between the inter-module bus bar 200 and the pack frame 310 can be ensured in the normal state of the battery pack 300.

[0073] However, when a flame or high-temperature gas is discharged from the battery cells constituting the battery pack 300 and the temperature of the pack frame 310 rises, thereby causing the second insulating layer 230 to become ceramicized and the first insulating layer 220 to expand, the insulation state can be maintained even when the inter-module bus bar 200 is in contact with the pack frame 310.

[0074] On the other hand, unlike the structure shown in FIG. 4, even when the inter-module bus bar is arranged not on the upper surface of the pack frame 310 but at other positions where the battery pack is configured and contacts a component made of an electrically conductive metal material, it is possible to maintain an insulating state between the inter-module bus bar and the component made of the electrically conductive metal material when a fire occurs in the battery pack.

[0075] As described above, in the present invention, when a fire occurs, the first insulating layer and the second insulating layer provided on the metal plate do not disappear and are maintained in a state of being provided on the outer surface of the metal plate. Further, since the expanded first insulating layer fills the cracks generated in the second insulating layer, the metal plate can be prevented from being exposed to the outside. Therefore, even when the inter-module bus bar is in contact with an adjacent metal component, an insulating state can be maintained.

[0076] Those having ordinary knowledge in the field to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above description.

Explanation of Reference Numerals

[0077] 110, 210 Metal plate 120 Insulating tape 130 Silicone Tube 200 Inter-module bus bar 220 First insulating layer 230 Second insulating layer 240 Electrical connection part 241 Opening 300 Battery pack 301 Battery module 310 Pack frame 311 Upper surface of pack frame 320 Battery pack housing

Claims

1. A metal plate for electrical connection, a first insulating layer covering at least a part of the metal plate, a second insulating layer provided on the first insulating layer, comprising, the first insulating layer contains a flame-retardant silicone having a property of expanding at high temperature, the second insulating layer contains a high heat-resistant silicone that ceramifies at high temperature, an inter-module bus bar.

2. The temperature at which the second insulating layer ceramifies is at least 1,200 °C, the inter-module bus bar according to claim 1.

3. When the second insulating layer ceramifies and cracks occur during temperature rise, the first insulating layer expands and is inserted between the cracks to fill the space in the cracks, the inter-module bus bar according to claim 1.

4. When the first insulating layer expands, the metal plate inside the first insulating layer and the second insulating layer is not exposed, the inter-module bus bar according to claim 3.

5. Both ends of the metal plate are not provided with the first insulating layer and the second insulating layer, and the metal plate is exposed to form an electrical connection part, the inter-module bus bar according to claim 1.

6. The electrical connection part has one or more connection openings formed therein, the inter-module bus bar according to claim 5.

7. A battery pack in which battery modules are electrically connected via the inter-module bus bar according to any one of claims 1 to 6.

8. A battery pack housing that houses two or more battery modules, a pack frame in which battery modules are arranged in a space partitioned inside for fixing the positions of the battery modules, an inter-module bus bar for electrically connecting the battery modules, comprising, in the inter-module bus bar, the first insulating layer and the second insulating layer are arranged on the upper surface of the pack frame, and the electrical connection parts at both ends without the first insulating layer and the second insulating layer are coupled to the connectors of the battery modules, the battery pack according to claim 7.

9. When the second insulating layer ceramifies due to the temperature rise of the pack frame and the first insulating layer expands, the metal plate is not exposed in a state where the inter-module bus bar is in contact with the pack frame, and the insulation state is maintained, the battery pack according to claim 8.

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