Bus bar assembly and battery pack including the same

Abstract

A bus bar assembly according to an embodiment of the present invention comprises: a bus bar for guiding an electrical connection within a battery pack; and a glass fiber layer including glass fibers and surrounding the bus bar. At least one glass fiber forms a glass fiber bundle, and a refractory silicone layer is coated on the surface of the glass fiber bundle.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2023-0011441 filed on January 30, 2023, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

[0003] The present disclosure relates to a bus bar assembly and a battery pack including the same, and more particularly, to a bus bar assembly having improved fire resistance and a battery pack including the same. Background Art

[0004] In modern society, with the daily use of portable devices such as mobile phones, notebook computers, video cameras and digital cameras, the development of technology in the field related to the above mobile devices has been activated. In addition, rechargeable / dischargeable secondary batteries are used as power sources for electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (P-HEV), etc., in an attempt to solve the air pollution caused by the use of fossil fuels by existing gasoline vehicles. Therefore, the demand for the development of secondary batteries is growing.

[0005] Currently commercial secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. Among them, lithium secondary batteries have attracted much attention due to their advantages (for example, they have almost no memory effect compared to nickel-based secondary batteries, can be charged and discharged freely, have a very low self-discharge rate, and have high energy density).

[0006] Such lithium secondary batteries generally use lithium oxides and carbon materials as positive electrode active materials and negative electrode active materials, respectively. The lithium secondary battery includes: an electrode assembly in which a positive electrode plate and a negative electrode plate coated with positive electrode active materials and negative electrode active materials, respectively, are arranged with a separator interposed therebetween; and an external material or battery case that hermetically houses the electrode assembly together with an electrolyte.

[0007] According to the shape of external materials, generally, lithium secondary batteries can be divided into can type secondary batteries in which an electrode assembly is incorporated into a metal can and pouch type batteries in which an electrode assembly is incorporated into a pouch of an aluminum laminate sheet.

[0008] In the case of a secondary battery for a small device, two to three battery cells are provided, but in the case of a secondary battery for a medium or large device (such as a car), a battery module electrically connected to a plurality of battery cells is used. In such a battery module, a plurality of battery cells are connected in series or in parallel to each other to form a battery assembly, thereby increasing capacity and output. In addition, one or more battery modules may be installed together with various control and protection systems (such as a BDU (battery disconnect unit), a BMS (battery management system), and a cooling system) to form a battery pack.

[0009] In a battery pack configured to gather multiple battery modules, the heat generated by multiple battery cells can be accumulated in a narrow space, so that the temperature can rise more quickly and excessively. In other words, a battery module stacked with multiple battery cells and a battery pack equipped with these battery modules can obtain high output, but it is not easy to remove the heat generated by the battery cells during charging and discharging. When the heat dissipation of the battery cells is not properly performed or a thermal runaway phenomenon occurs in the battery cells, the possibility of explosion or fire increases.

[0010] In addition, bus bars connected to the battery modules are provided inside the battery pack. Figure 1 is a plan view showing a conventional bus bar, and Figure 2 is shown along Figure 1 A cross-sectional view of the cross section taken along the cutting line AA' in FIG.

[0011] refer to Figure 1 and Figure 2 , the conventional bus bar 20 is a rod-shaped metal member extending in the longitudinal direction, and through holes for connecting to the terminal bus bars of the battery module may be formed at both ends of the bus bar 20. Such a bus bar 20 is configured to be responsible for the HV (high voltage) connection in the battery pack. The HV connection refers to a connection used as a power source to supply electric power, and the bus bar 20 is configured to guide the electrical connection of the battery module and generally includes a metal material with excellent electrical conductivity. As an example, the bus bar 20 may include a copper (Cu) material.

[0012] The cover member 20C may surround such a bus bar 20. The cover member 20C may include an electrically insulating material, and as an example, it may include a silicone material or an epoxy material. Since the cover member 20C surrounds the bus bar 20 through which a large current flows, the bus bar 20 may be prevented from contacting other electrical devices or conductive members except for the terminal bus bar of the battery module, thereby interrupting the generation of a short circuit.

[0013] In recent years, even if a fire occurs inside a battery pack, it is required that the battery pack has a device that does not eject flames to the outside of the battery pack. Since the flame generated inside the battery pack has a very high temperature of about 1000°C, the covering member 20C surrounding the bus bar 20 may melt, so that the bus bar 20 may be exposed. If the exposed bus bar 20 contacts another electrical component or a conductive member to cause a short circuit, the internal flame may spread further, and the flame may propagate to the outside of the battery pack. This may eventually cause the battery pack or a vehicle equipped with the battery pack to explode.

[0014] Therefore, it is necessary to develop a technology that can maintain the electrical insulation characteristics of the bus bar assembly even if flames are generated inside the battery pack. Summary of the invention

[0015] Technical issues

[0016] An object of the present disclosure is to provide a bus bar assembly that can maintain electrical insulation characteristics without melting even when a fire occurs inside a battery pack, and a battery pack including the bus bar assembly.

[0017] However, the technical problems to be solved by the embodiments of the present disclosure are not limited to the above-mentioned problems, and various extensions can be made within the scope of the technical concept included in the present disclosure.

[0018] Technical Solution

[0019] According to one embodiment of the present disclosure, a bus bar assembly is provided, comprising: a bus bar for guiding electrical connections inside a battery pack; and a glass fiber layer, the glass fiber layer comprising glass fibers and surrounding the bus bar, wherein at least one glass fiber forms a glass fiber bundle, and a fire-resistant silicone layer is coated on a surface of the glass fiber bundle.

[0020] In the glass fiber layer, gaps may be formed between the glass fiber bundles.

[0021] The glass fiber layer may be a fabric woven from the glass fiber bundles.

[0022] The glass fiber layer may be formed such that the glass fiber bundles are crossed and stacked layer by layer.

[0023] The refractory silicone layer may include a silicon material that forms a ceramic at high temperatures.

[0024] According to another embodiment of the present disclosure, a battery pack is provided, comprising: at least one bus bar assembly as described above; a battery module; a BDU (battery disconnect unit) module, which controls the electrical connection of the battery module; and a BMS (battery management system) module, which monitors and controls the operation of the battery module, wherein the at least one bus bar assembly electrically connects at least one of the battery modules, between the battery module and the BDU module, between the battery module and the BMS module, or between the BDU module and the BMS module.

[0025] Beneficial Effects

[0026] According to an embodiment of the present disclosure, a glass fiber layer surrounding a bus bar is formed by using a glass fiber bundle and a fire-resistant silicone layer coated on the glass fiber bundle, so that the electrical insulation characteristics of the bus bar assembly can be maintained even under high temperature or flame conditions. Specifically, the present disclosure utilizes the rigidity of the glass fiber while ensuring fire resistance through the fire-resistant silicone layer, so that this makes it possible to protect the internal bus bar even under high temperature or flame conditions.

[0027] Furthermore, gas generated when the bus bar assembly is exposed to flames may be quickly discharged due to pores provided in the glass fiber layer.

[0028] Effects obtainable from the present disclosure are not limited to the above-described effects, and other additional effects not mentioned herein will be clearly understood by those skilled in the art from the description of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a plan view showing a conventional bus bar.

[0030] Figure 2 is shown along Figure 1 A cross-sectional view of the cross section taken along the cutting line AA' in FIG.

[0031] Figure 3 is a plan view showing a battery pack according to an embodiment of the present disclosure.

[0032] Figure 4 It is shown that the Figure 3 A three-dimensional view of a battery module in a battery pack.

[0033] Figure 5 It is shown Figure 4 A partial perspective view of a battery module in which a module frame and end plates are removed.

[0034] Figure 6 is a plan view showing a bus bar assembly according to an embodiment of the present disclosure.

[0035] Figure 7 is shown along Figure 6 A cross-sectional view of the cross section taken along the cutting line BB'.

[0036] Figure 8 is a plan view showing a bus bar assembly according to another embodiment of the present disclosure.

[0037] Fig. 9 is shown along Figure 8 A cross-sectional view of the section taken along the cutting line CC'. DETAILED DESCRIPTION

[0038] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily perform them. The present disclosure can be modified in various different ways and is not limited to the embodiments set forth herein.

[0039] For clarity, explanations of parts not relevant to the description will be omitted, and the same reference numerals will be used throughout the description to denote the same or like elements.

[0040] In addition, in the drawings, for the convenience of description, the size and thickness of each element are arbitrarily shown, and the present disclosure is not necessarily limited to the size and thickness shown in the drawings. In the drawings, for the sake of clarity, the thickness of layers, regions, etc. are exaggerated. In the drawings, for the convenience of description, the thickness of components and regions is exaggerated.

[0041] In addition, it should be understood that when an element such as a layer, film, region, or plate is referred to as being "on" or "over" another element, it can be directly on the other element, or intervening elements may also be present. Conversely, when an element is referred to as being "directly on" another element, this means that no other intervening elements are present. In addition, a particular portion being "on" or "over" a reference portion means that the particular portion is above or below the reference portion, and does not specifically mean that the particular portion is "on" or "over" in the opposite direction of gravity.

[0042] Furthermore, throughout the specification, when a part is referred to as “including” or “comprising” a certain component, it means that the part may further include other components, without excluding the other components, unless otherwise specified.

[0043] Furthermore, throughout the specification, when referred to as “plane”, this means observing the target portion from the upper side, and when referred to as “cross section”, this means observing the target portion from one side of the cross section cut vertically.

[0044] Figure 3 is a plan view showing a battery pack according to an embodiment of the present disclosure.

[0045] refer to Figure 3 , a battery pack 1000 according to one embodiment of the present disclosure includes a bus bar assembly 100; a battery module 1200; a BDU (battery disconnect unit) module 1300 for controlling the electrical connection of the battery module 1200; and a BMS (battery management system) module 1400 that monitors and controls the operation of the battery module 1200. At least one bus bar assembly 100 according to the present embodiment electrically connects at least one of the battery modules 1200, the battery module 1200 and the BDU module 1300, the battery module 1200 and the BMS module 1400, or the BDU module 1300 and the BMS module 1400. Specifically, a plurality of battery modules 1200 may be accommodated in a battery pack frame 1100, and the electrical connection between the battery modules 1200 or the electrical connection between the battery modules 1200 and the BDU module 1300 may be performed by the bus bar assembly 100. That is, the bus bar assembly 100 according to the present embodiment may be responsible for HV (high voltage) connection. Here, the HV connection is a connection that plays the role of a power source for supplying electric power requiring a high voltage, and means a connection between battery cells or a connection between battery modules.

[0046] In addition, the BDU module 1300 is a member for controlling the electrical connection of the battery module 1200, and can cut off the power supply between the power converter and the battery module 1200. When the current exceeds the set range, the BDU module 1300 can cut off the power supply to the battery pack 1000 to ensure the safety of the battery pack 1000.

[0047] In addition, the LV connecting member 100' according to the present embodiment can be responsible for the electrical connection between the battery module 1200 and the BMS module 1400. The electrical connection here is a LV (low voltage) connection, which means a sensing connection for detecting and controlling the voltage and temperature of the battery module 1200. Specifically, sensors and the like are arranged inside the battery module 1200, and the real-time temperature information or voltage information of the battery module 1200 is transmitted to the BMS module 1400 via the LV connecting member 100'. The real-time operating state of the battery module 1200 can be monitored and controlled via the BMS module 1400. Although not specifically shown, the HV current sensor can be integrated into the BMS module 1400. In this case, the bus bar assembly according to the present embodiment can be responsible for the electrical connection between the battery module 1200 and the BMS module 1400 or between the BDU module 1300 and the BMS module 1400.

[0048] Next, we will refer to Figure 4 and Figure 5A battery module 1200 according to the present embodiment is described. In this regard, the battery module 1200 described below has one exemplary structure of a battery module including a plurality of battery cells 11 , and various types of battery modules including a plurality of battery cells may be applied.

[0049] Figure 4 It is shown that the Figure 3 A three-dimensional view of a battery module in a battery pack. Figure 5 It is shown Figure 4 A partial perspective view of a battery module in which a module frame and end plates are removed.

[0050] refer to Figure 4 and Figure 5 The battery module 1200 according to the present embodiment may include a battery cell stack 11A in which a plurality of battery cells 11 are stacked. Figure 5 Such a battery cell stack 11A may be accommodated in a module frame 30 and an end plate 40 .

[0051] The battery cell 11 may be a pouch-type battery cell. Such a pouch-type battery cell may be formed by housing an electrode assembly in a pouch shell made of a laminate sheet including a resin layer and a metal layer, and then fusing the peripheral portion of the pouch shell. Such a battery cell 11 may be formed into a rectangular sheet structure. The electrode lead 11L connected to the electrode assembly protrudes to the outside of the pouch shell, wherein the electrode leads 11L of each battery cell 11 may be electrically connected to each other via a lead bus bar 21. On the other hand, at least one electrode lead 11L may be connected to a terminal bus bar 22. As Figure 4 As shown, a portion of the terminal bus bar 22 may be exposed to the outside of the battery module 1200. Both the lead bus bar 21 and the terminal bus bar 22 may include a metal material having excellent electrical conductivity.

[0052] The bus bar assembly 100 according to the present embodiment is electrically connected to such a terminal bus bar 22, so that the above-mentioned HV connection can be achieved. That is, the battery module 1200 can be electrically connected to another battery module 1200, a BDU module 1300, or a BMS module 1400 via the bus bar assembly 100 connected to the terminal bus bar 22.

[0053] As mentioned above, Figure 4 and Figure 5The battery cells and battery modules described in are exemplary structures, and the types or forms of the battery cells and battery modules included in the battery pack to which the bus bar assembly according to the present embodiment is applied are not particularly limited. That is, although the pouch-type battery cells are described as examples, prismatic battery cells or cylindrical battery cells may also be applied to the battery modules according to the embodiments of the present disclosure. In addition, a battery module in which the battery cells are accommodated in a module frame is described as an example, but a CTP (cell to pack) type battery module in which a plurality of battery cells are mounted on a battery pack without being accommodated in a module frame may also be applied as an example of the present disclosure.

[0054] Next, we will refer to Figures 6 to 9 A bus bar assembly according to an embodiment of the present disclosure is described in detail.

[0055] Figure 6 is a plan view showing a bus bar assembly according to an embodiment of the present disclosure. Figure 7 is shown along Figure 6 A cross-sectional view of the cross section taken along the cutting line BB'.

[0056] refer to Figure 6 and Figure 7 , the bus bar assembly 100 a according to an embodiment of the present disclosure includes a bus bar 200 for guiding electrical connection within a battery pack 1000 ; and a glass fiber layer 400 including glass fibers and surrounding the bus bar 200 .

[0057] The bus bar 200 is configured to guide the electrical connection (ie, HV connection) of the battery module and may include a metal material having excellent conductivity. As an example, the bus bar 200 may include a copper (Cu) material. The bus bar 200 may be a metal rod extending in the longitudinal direction Ld.

[0058] In the glass fiber layer 400 according to the present embodiment, at least one glass fiber forms a glass fiber bundle 400S, and the fire-resistant silicone layer 300 may be applied to the surface of the glass fiber bundle 400S. As an example, the glass fiber bundle 400S may be a single glass fiber, or may be a member in which a plurality of glass fibers are twisted and wound. Figure 6 and Figure 7 , a state in which the fire-resistant silicone layer 300 is formed on the surface of the glass fiber bundle 400S is indicated as a glass fiber member 400G.

[0059] The fire-resistant silicone layer 300 may include a fire-resistant silicone material. A method of forming the fire-resistant silicone layer 300 on the surface of the glass fiber bundle 400S is not particularly limited.

[0060] The glass fiber bundle 400S coated by the fire-resistant silicone layer 300 having electrical insulation properties serves as an insulating layer to protect the bus bar 200 , thereby preventing the bus bar 200 from contacting other electrical devices or conductive members and causing a short circuit.

[0061] Unlike common silicone materials that may burn when exposed to flames or high temperatures, refractory silicone materials are materials that are formed into ceramics when exposed to flames or high temperatures. Refractory silicone materials can be silicon materials that are formed into ceramics when the temperature exceeds a specific temperature. Refractory silicone materials can include silicone polymers and silicon dioxide. The silicone polymers used can be polysiloxane compounds with vinyl as functional groups, and correspond to substrates for refractory silicone materials. Silicon dioxide can be fumed silica, which is a reinforcing filler contained in silicone polymers. Using metallic silicon as the main raw material, by reacting with hydrochloric acid and a purification process, a high-purity silicone chloride (SiCl4) compound can be produced, and can be reacted with hydrogen and oxygen under a high-temperature flame to obtain fumed silica. In addition, the refractory silicone can contain platinum Pt as a catalyst.

[0062] When the refractory silicone material is exposed to flame or high temperature, silicon dioxide (SiO2) crosslinks with the decomposition of the silicone polymer to form a ceramic material. The refractory silicone layer 300 according to the present embodiment does not burn or melt, but can form a ceramic and maintain electrical insulation properties even when exposed to flame or placed in a high temperature environment.

[0063] At this time, in the glass fiber layer 400, a gap S may be formed between the glass fiber bundles 400S. As an example, the glass fiber layer 400 according to the present embodiment may be a fabric formed in such a manner that the glass fiber bundles 400S coated with the fire-resistant silicone layer 300 are woven. The weaving method is not particularly limited, and various weaving methods such as plain weaving, twill weaving, and satin weaving may be applied. Since the glass fiber layer 400 is a fabric, the gap S may be formed between the glass fiber bundles 400S woven in the glass fiber layer 400, and the gap may also be formed between the glass fiber layer 400 and the bus bar 200.

[0064] Figure 8 is a plan view showing a bus bar assembly according to another embodiment of the present disclosure. Fig. 9 is shown along Figure 8 A cross-sectional view of the section taken along the cutting line CC'.

[0065] refer to Figure 8 and Fig. 9, a bus bar assembly 100b according to another embodiment of the present disclosure may include a bus bar 200 for guiding electrical connection inside a battery pack 1000; and a glass fiber layer 400 including glass fibers and surrounding the bus bar 200. In the glass fiber layer 400, at least one glass fiber forms a glass fiber bundle 400S, and a fire-resistant silicone layer 300 may be applied to a surface of the glass fiber bundle 400S. The description of the bus bar 200 and the fire-resistant silicone layer 300 is omitted because it is repeated with the above content.

[0066] In the glass fiber layer 400, a gap S may be formed between the glass fiber bundles 400S. As an example, the glass fiber layer 400 according to the present embodiment may be formed such that the glass fiber bundles 400S coated with the fire-resistant silicone layer 300 are crossed and stacked layer by layer. The gap S may be formed between the cross-laminated glass fiber bundles 400S within the glass fiber layer 400, or the gap may also be formed between the glass fiber layer 400 and the bus bar 200.

[0067] In summary, unlike the configuration in which the outer peripheral surface of the bus bar 200 is directly coated with a fire-resistant silicone material, the present embodiment may have a configuration in which the glass fiber bundle 400S coated with a fire-resistant silicone layer 300 is woven or stacked layer by layer. That is, since the glass fiber occupies most of the covering material of the bus bar 200, the bus bar assemblies 100a and 100b according to the present embodiment have more excellent rigidity than those bus bar assemblies simply coated with a fire-resistant silicone material. In addition, since the surface of the glass fiber bundle 400S is coated with a fire-resistant silicone layer 300, in addition to the rigidity of the glass fiber, the bus bar assemblies 100a and 100b can also have fire resistance. When exposed to flames or high temperatures, the outer fire-resistant silicone layer 300 is formed as a ceramic and expands to serve as a type of heat insulation layer. The heat transfer to the interior where the bus bar 200 is located can be delayed.

[0068] In addition, as described above, the glass fiber layer 400 in which the glass fiber bundles 400S are woven or stacked layer by layer may be formed with gaps S between the glass fiber bundles 400S. When the bus bar assembly 100 is exposed to flames or reaches a high temperature, gas may be generated in the fire-resistant silicone layer 300. The gas generated in the fire-resistant silicone layer 300 may accelerate internal combustion and may damage the structural stability of the bus bar assembly 100, thereby adversely affecting the insulation performance of the bus bar 200. In the case of the present embodiment, since the structure allows the gaps S to be formed between the glass fiber bundles 400S, such gas can be quickly discharged to the outside. Therefore, the above-mentioned problem caused by the unexhausted gas can be solved.

[0069] In this embodiment, terms indicating directions such as front, back, left, right, upper and lower sides have been used, but the terms used are provided only for the convenience of description and may become different depending on the position of the object, the position of the observer, etc.

[0070] One or more battery modules according to the embodiments of the present disclosure described above may be installed together with various control and protection systems such as a BMS (Battery Management System) module, a BDU (Battery Disconnect Unit) module, and a cooling system to form a battery pack.

[0071] The battery module or battery pack can be applied to various devices. Specifically, it can be applied to vehicle devices such as electric bicycles, electric vehicles, hybrid electric vehicles or ESS (Energy Storage System), and can be applied to various devices that can use secondary batteries, but is not limited thereto.

[0072] Although the present invention has been described in detail with reference to the preferred embodiments of the present invention, the scope of the present disclosure is not limited thereto, and those skilled in the art may make various modifications and improvements using the basic concepts of the present disclosure defined in the appended claims, which also fall within the scope of the present disclosure.

[0073] Description of Reference Numerals

[0074] 100a, 100b: Bus bar assembly

[0075] 200: Busbar

[0076] 300: Fire-resistant silicone layer

[0077] 400: Glass fiber layer

[0078] 400S: Fiberglass Bundle

[0079] 1000: Battery Pack

[0080] 1100: Battery Pack Frame

[0081] 1200: Battery module

[0082] 1300: BDU module

[0083] 1400: BMS module

Claims

1. A bus bar assembly, comprising: A bus bar used to guide electrical connections inside the battery pack; as well as a fiberglass layer, the fiberglass layer comprising glass fibers and surrounding the bus bar, At least one glass fiber forms a glass fiber bundle, and a fire-resistant silicone resin layer is coated on the surface of the glass fiber bundle.

2. The bus bar assembly according to claim 1, wherein: In the glass fiber layer, gaps are formed between the glass fiber bundles.

3. The bus bar assembly according to claim 1, wherein: The glass fiber layer is a fabric formed by weaving the glass fiber bundles.

4. The bus bar assembly according to claim 1, wherein: The glass fiber layers are formed such that the glass fiber bundles are crossed and stacked layer by layer.

5. The bus bar assembly according to claim 1, wherein: The refractory silicone layer includes a silicon material formed into a ceramic at a high temperature.

6. A battery pack, comprising: At least one bus bar assembly according to claim 1; Battery modules; A battery disconnect unit BDU module, the BDU module controls the electrical connection of the battery module; as well as A battery management system (BMS) module, which monitors and controls the operation of the battery module, Among them, the at least one bus bar assembly is electrically connected in at least one of the following electrical connection modes: electrically connected between the battery modules, electrically connected between the battery module and the BDU module, electrically connected between the battery module and the BMS module, or electrically connected between the BDU module and the BMS module.

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