Busbar assembly and battery pack including same

Abstract

A bus bar assembly according to an embodiment of the present invention includes a bus bar for guiding electrical connections within a battery pack, and a glass fiber layer including glass fibers and encasing the bus bar, wherein at least one glass fiber forms a glass fiber strand, and a refractory silicone layer is coated on a surface of the glass fiber strand.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0011441, filed January 30, 2023, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a busbar assembly and a battery pack including the same, and more particularly to a busbar assembly with improved fire resistance and a battery pack including the same. [Background technology]

[0003] In modern society, the use of portable devices such as mobile phones, laptops, video cameras, and digital cameras has become commonplace, and technological development in fields related to these mobile devices is accelerating. Furthermore, rechargeable secondary batteries are being used as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), and other vehicles as a way to address air pollution caused by conventional gasoline-powered vehicles that use fossil fuels, and this has led to an increased need for the development of secondary batteries.

[0004] Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Of these, lithium secondary batteries are attracting attention due to their advantages over nickel-based secondary batteries, such as almost no memory effect, freedom in charging and discharging, extremely low self-discharge rate, and high energy density.

[0005] Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as positive and negative electrode active materials, respectively, and include an electrode assembly in which positive and negative electrode plates coated with the positive and negative electrode active materials are arranged with a separator sandwiched therebetween, and a battery case that hermetically houses the electrode assembly together with an electrolyte.

[0006] Generally, lithium secondary batteries can be classified into can-type secondary batteries, in which an electrode assembly is housed in a metal can, and pouch-type secondary batteries, in which an electrode assembly is housed in a pouch made of an aluminum laminate sheet, depending on the shape of the exterior material.

[0007] Secondary batteries used in small devices are configured with two or three battery cells, while secondary batteries used in medium- to large-sized devices such as automobiles use battery modules in which multiple battery cells are electrically connected. These battery modules improve capacity and output by connecting multiple battery cells in series or parallel to form a battery cell stack. One or more battery modules can also be mounted with various control and protection systems, such as a Battery Disconnect Unit (BDU), Battery Management System (BMS), and cooling system, to form a battery pack.

[0008] In a battery pack made up of multiple battery modules, the heat generated from the multiple battery cells can be combined in a small space, causing a rapid temperature rise. In other words, a battery module with multiple stacked battery cells and a battery pack equipped with such a battery module can produce high output, but there is a high possibility of explosion or fire if the battery cells do not properly dissipate heat or if thermal runaway occurs in the battery cells.

[0009] Meanwhile, a bus bar connected to the battery module is provided inside the battery pack. Fig. 1 is a plan view showing a conventional bus bar, and Fig. 2 is a cross-sectional view taken along the line A-A' in Fig. 1.

[0010] 1 and 2, a conventional busbar 20 is a rod-shaped metal member extending in a longitudinal direction, and through-holes may be formed at both ends of the busbar 20 for connection to terminal busbars of a battery module. Such a busbar 20 is configured to perform HV (High Voltage) connection in a battery pack. HV connection refers to a connection that serves as a power source for supplying power, and the busbar 20 is configured to guide the electrical connection of the battery modules and is generally made of a metal material with excellent electrical conductivity. For example, the busbar 20 may include a copper (Cu) material.

[0011] The covering member 20C can encase such bus bars 20. The covering member 20C can include an electrically insulating material, for example, a silicone material or an epoxy material. Because the covering member 20C encases the bus bars 20, through which a high current flows, the bus bars 20 are prevented from coming into contact with other electrical components or conductive members other than the terminal bus bars of the battery module, which could cause a short circuit.

[0012] Recently, battery packs have been required to have equipment that prevents flames from spreading to the outside of the battery pack even if a fire occurs inside the battery pack. A flame that breaks out inside the battery pack can reach temperatures as high as approximately 1000°C, which can melt the covering material 20C that encases the busbar 20 and expose the busbar 20. If the exposed busbar 20 comes into contact with other electrical components or conductive members, causing a short circuit, the internal flame can spread further and potentially propagate to the outside of the battery pack. Ultimately, this can lead to an explosion of the battery pack or the vehicle in which the battery pack is installed.

[0013] In response to this, there is a need for technological development of busbar assemblies that can maintain electrical insulation even if a flame occurs inside the battery pack. Summary of the Invention [Problem to be solved by the invention]

[0014] An object of the present invention is to provide a bus bar assembly that can maintain electrical insulation without melting even if a flame occurs inside the battery pack, and a battery pack including the bus bar assembly.

[0015] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0016] A bus bar assembly according to an embodiment of the present invention includes a bus bar for guiding electrical connections within a battery pack, and a glass fiber layer including glass fibers and encasing the bus bar, wherein at least one glass fiber forms a glass fiber strand, and a refractory silicone layer is coated on a surface of the glass fiber strand.

[0017] In the glass fiber layer, voids may be formed between the glass fiber strands.

[0018] The glass fiber layer may be a fabric in which the glass fiber strands are woven.

[0019] The glass fiber layer may have a configuration in which the glass fiber strands are cross-laminated for each layer.

[0020] The refractory silicon layer may include a silicon material that is ceramified at high heat.

[0021] A battery pack according to an embodiment of the present invention includes at least one busbar assembly, battery modules, a BDU (Battery Disconnect Unit) module for controlling electrical connections of the battery modules, and a BMS (Battery Management System) module for monitoring and controlling operation of the battery modules. The at least one busbar assembly electrically connects at least one of the battery modules, the battery modules and the BDU module, the battery modules and the BMS module, or the BDU module and the BMS module. [Effects of the Invention]

[0022] According to an embodiment of the present invention, the glass fiber layer surrounding the bus bar is formed using glass fiber strands and a fire-resistant silicone layer coated thereon, thereby maintaining electrical insulation of the bus bar assembly even in high heat or flame conditions. Specifically, while utilizing the rigidity of the glass fiber, the fire-resistant silicone layer ensures fire resistance, thereby protecting the internal bus bar even in fire or high heat conditions.

[0023] Additionally, the voids provided within the glass fiber layers allow for rapid evacuation of gases generated when the bus bar assembly is exposed to a flame.

[0024] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 10 is a plan view showing a conventional bus bar. [Figure 2] FIG. 2 is a cross-sectional view showing a cross section taken along the line AA' in FIG. [Figure 3] 1 is a plan view showing a battery pack according to an embodiment of the present invention; [Figure 4]4 is a perspective view showing one of the battery modules included in the battery pack of FIG. 3. FIG. [Figure 5] 5 is a partial perspective view showing the battery module of FIG. 4 with a module frame and end plates removed. FIG. [Figure 6] FIG. 2 is a plan view showing a busbar assembly according to an embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view showing a cross section taken along the line BB' in FIG. [Figure 8] FIG. 10 is a plan view showing a busbar assembly according to another embodiment of the present invention. [Figure 9] 9 is a cross-sectional view showing a cross section taken along the line CC' in FIG. 8. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will now be described in detail with reference to the accompanying drawings, in which various embodiments of the present invention can be easily implemented by those skilled in the art. The present invention can be implemented in several different forms and is not limited to the examples described herein.

[0027] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0028] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are exaggerated to clearly show multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0029] Furthermore, when a layer, film, region, plate, or other part is said to be "on" or "above" another part, this includes not only the case where it is "directly above" that other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in the middle. Furthermore, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being "above" or "above" facing the opposite direction of gravity.

[0030] Furthermore, throughout the specification, when a part "comprises" a certain element, it does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0031] Also, throughout the specification, "on a plane" means when the target part is viewed from above, and "on a cross section" means when the target part is cut vertically and viewed from the side.

[0032] FIG. 3 is a plan view showing a battery pack according to one embodiment of the present invention.

[0033] 3 , a battery pack 1000 according to an embodiment of the present invention includes a busbar assembly 100, battery modules 1200, a battery disconnect unit (BDU) module 1300 for controlling the electrical connection of the battery modules 1200, and a battery management system (BMS) module 1400 for monitoring and controlling the operation of the battery modules 1200. At least one busbar assembly 100 according to this embodiment electrically connects at least one of the battery modules 1200 together, the battery modules 1200 and the BDU module 1300 together, the battery modules 1200 and the BMS module 1400 together, or the BDU module 1300 and the BMS module 1400 together. Specifically, a plurality of battery modules 1200 may be housed in a pack frame 1100, and electrical connection between the battery modules 1200 and the battery modules 1200 and the BDU module 1300 may be made by the busbar assembly 100. That is, the bus bar assembly 100 according to this embodiment can serve as an HV (High Voltage) connection. Here, the HV connection is a connection that serves as a power source for supplying power that requires high voltage, and refers to a connection between battery cells or between battery modules.

[0034] Meanwhile, the BDU module 1300 is a component for controlling the electrical connection of the battery module 1200, and can cut off the power supply between the power conversion device and the battery module 1200. The BDU module 1300 can ensure the safety of the battery pack 1000 by cutting off the power supply to the battery pack 1000 when a condition occurs in which the current exceeds a set range.

[0035] Meanwhile, the LV connection member 100′ according to this embodiment may be responsible for electrical connection between the battery module 1200 and the BMS module 1400. The electrical connection here is a low voltage (LV) connection, which refers to a sensing connection for sensing and controlling the voltage and temperature of the battery module 1200. Specifically, sensors and the like are disposed inside the battery module 1200, and real-time temperature and voltage information of the battery module 1200 is transmitted to the BMS module 1400 through the LV connection member 100′. The real-time operating status of the battery module 1200 can be monitored and controlled through the BMS module 1400. Although not specifically shown, an HV current sensor may be integrated into the BMS module 1400. In this case, the busbar assembly according to this embodiment may be responsible for electrical connection between the battery module 1200 and the BMS module 1400 or between the BDU module 1300 and the BMS module 1400.

[0036] A battery module 1200 according to this embodiment will be described below with reference to Figures 4 and 5. However, the battery module 1200 described below is 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.

[0037] Fig. 4 is a perspective view showing one of the battery modules included in the battery pack of Fig. 3. Fig. 5 is a partial perspective view showing the battery module of Fig. 4 with a module frame and an end plate removed.

[0038] 4 and 5, a battery module 1200 according to this embodiment may include a battery cell stack 11A in which a plurality of battery cells 11 are stacked. The battery cell stack 11A is shown in Fig. 5. Such a battery cell stack 11A may be housed in a module frame 30 and end plates 40.

[0039] The battery cells 11 may be pouch-type battery cells. Such pouch-type battery cells may be formed by encapsulating an electrode assembly in a pouch case made of a laminate sheet including a resin layer and a metal layer, and then fusing the outer periphery of the pouch case. Such battery cells 11 may be formed in a rectangular sheet structure. Electrode leads 11L connected to the electrode assembly protrude from the pouch case, and the electrode leads 11L of each battery cell 11 may be electrically connected to each other via a lead bus bar 21. Meanwhile, at least one electrode lead 11L may be connected to a terminal bus bar 22. A portion of the terminal bus bar 22 may be exposed to the outside of the battery module 1200, as shown in FIG. 4 . The lead bus bar 21 and the terminal bus bar 22 may both include a metal material with excellent electrical conductivity.

[0040] The busbar assembly 100 according to this embodiment is electrically connected to the terminal busbar 22, and the above-described HV connection can be performed. 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 busbar assembly 100 connected to the terminal busbar 22.

[0041] As described above, the battery cells and battery modules described in Figures 4 and 5 are exemplary structures, and there are no particular limitations on the types or shapes of the battery cells and battery modules included in the battery pack to which the busbar assembly according to this embodiment is applied. That is, although pouch-type battery cells have been described as an example, prismatic battery cells and cylindrical battery cells can also be applied to the battery module according to this embodiment. Furthermore, although a battery module in which battery cells are housed in a module frame has been described as an example, a CTP (cell to pack) type battery module in which multiple battery cells are attached to a battery pack without being housed in a module frame can also be applied as an example of the present invention.

[0042] Hereinafter, a busbar assembly according to an embodiment of the present invention will be described in detail with reference to FIGS.

[0043] Fig. 6 is a plan view showing a busbar assembly according to an embodiment of the present invention, and Fig. 7 is a cross-sectional view showing a cross section taken along the line BB' in Fig. 6.

[0044] 6 and 7, a bus bar assembly 100a according to one embodiment of the present invention includes a bus bar 200 for guiding electrical connections within a battery pack 1000; and a glass fiber layer 400 including glass fiber and wrapping the bus bar 200.

[0045] The busbar 200 is a component for guiding the electrical connection of the battery modules, i.e., the HV connection, and may include a metal material with excellent electrical conductivity. For example, the busbar 200 may include a copper (Cu) material. The busbar 200 may be a metal rod extending in the length direction (Ld).

[0046] In the glass fiber layer 400 according to this embodiment, at least one glass fiber forms a glass fiber strand 400S, and the surface of the glass fiber strand 400S can be coated with a refractory silicone layer 300. For example, the glass fiber strand 400S can be a single glass fiber or a member in which multiple glass fibers are twisted. In Figures 6 and 7, the glass fiber strand 400S on which the refractory silicone layer 300 is formed is shown as a glass fiber member 400G.

[0047] The refractory silicone layer 300 may include a refractory silicone material. There is no particular limitation on the method for forming the refractory silicone layer 300 on the surface of the glass fiber strands 400S.

[0048] The glass fiber strands 400S coated with the electrically insulating refractory silicone layer 300 function as an insulating layer to protect the bus bar 200 and prevent the bus bar 200 from coming into contact with other electrical equipment or conductive components and causing a short circuit.

[0049] Unlike typical silicon materials that burn when exposed to flames or high heat, the refractory silicon material is a material that ceramifies when exposed to flames or high heat. The refractory silicon material may be a silicon material that ceramizes above a certain temperature. The refractory silicon material may include a silicon polymer and silica. The silicon polymer may be a polysiloxane-based compound having a vinyl group as a functional group and corresponds to the base material of the refractory silicon material. Silica may be a reinforcing filler contained in the silicon polymer, and may be fumed silica. High-purity silicon chloride (SiCl4) compound can be produced from metal silicon as the main raw material through a reaction with hydrochloric acid and a purification process, and fumed silica can be obtained by reacting this compound with hydrogen and oxygen in a high-temperature flame. The refractory silicon material may also include platinum (Pt) as a catalyst.

[0050] When the refractory silicone material is exposed to flame or high heat, the silicone polymer decomposes and silica (SiO2) cross-links to form a ceramic material. The refractory silicone layer 300 according to this embodiment is ceramified and maintains electrical insulation without burning or melting, even when exposed to internal flame or in a high-heat environment.

[0051] At this time, gaps (S) may be formed between the glass fiber strands 400S in the glass fiber layer 400. As an example, the glass fiber layer 400 according to this embodiment may be a fabric in which the glass fiber strands 400S coated with the refractory silicone layer 300 are woven. There are no particular limitations on the type of weave, and various weave types such as plain weave, twill weave, and satin weave may be applied. Because the glass fiber layer 400 is a fabric, gaps (S) may be formed between the woven glass fiber strands 400S in the glass fiber layer 400, and gaps may also be formed between the glass fiber layer 400 and the bus bar 200.

[0052] Fig. 8 is a plan view showing a busbar assembly according to another embodiment of the present invention, and Fig. 9 is a cross-sectional view showing a cross section taken along the line CC' in Fig. 8.

[0053] 8 and 9, a bus bar assembly 100b according to another embodiment of the present invention includes a bus bar 200 for guiding electrical connections within a battery pack 1000, and a glass fiber layer 400 containing glass fiber and wrapping the bus bar 200. In the glass fiber layer 400, at least one glass fiber forms a glass fiber strand 400S, and a refractory silicone layer 300 may be coated on the surface of the glass fiber strand 400S. A description of the bus bar 200 and the refractory silicone layer 300 will be omitted as it is the same as that described above.

[0054] In the glass fiber layer 400, gaps (S) may be formed between the glass fiber strands 400S. As an example, the glass fiber layer 400 according to this embodiment may have a form in which glass fiber strands 400S coated with the refractory silicone layer 300 are cross-laminated for each layer. Gaps (S) may be formed between the cross-laminated glass fiber strands 400S in the glass fiber layer 400, and gaps may also be formed between the glass fiber layer 400 and the bus bar 200.

[0055] In summary, unlike a configuration in which the outer surface of the busbar 200 is directly coated with a fire-resistant silicone material, in this embodiment, the glass fiber strands 400S coated with the fire-resistant silicone layer 300 may be woven or layered. That is, because glass fiber accounts for the majority of the coating material of the busbar 200, the busbar assemblies 100a, 100b according to this embodiment have superior rigidity compared to those simply coated with a fire-resistant silicone material. At the same time, because the surface of the glass fiber strands 400S is coated with the fire-resistant silicone layer 300, the busbar assemblies 100a, 100b can have fire resistance in addition to the rigidity of glass fiber. When exposed to flames or high heat, the outer fire-resistant silicone layer 300 becomes ceramicized and expands, functioning as a type of thermal insulation layer and slowing heat transfer to the interior where the busbar 200 is located.

[0056] As described above, the glass fiber layer 400, in which the glass fiber strands 400S are woven or layered, may have voids (S) between the glass fiber strands 400S. If the bus bar assembly 100 is exposed to fire or heated to high temperatures, gas may be generated from the refractory silicone layer 300. The gas generated from the refractory silicone layer 300 may accelerate an internal fire, impair the structural stability of the bus bar assembly 100, and adversely affect the insulating performance of the bus bar 200. In this embodiment, because the voids (S) are formed between the glass fiber strands 400S, the gas can be quickly discharged to the outside. This solves the problems caused by undischarged gas.

[0057] In this embodiment, terms indicating directions such as front, back, left, right, up, and down are used, but these terms are used for convenience of explanation and may differ depending on the position of the object in question, the position of the observer, etc.

[0058] One or more battery modules according to the above-described embodiments may be mounted together with various control and protection systems such as a BMS (Battery Management System), a BDU (Battery Disconnect Unit), and a cooling system to form a battery pack.

[0059] The battery module or battery pack can be applied to various devices, specifically, but not limited to, transportation means such as electric bicycles, electric vehicles, and hybrids, and ESS (Energy Storage Systems).

[0060] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0061] 100a, 100b Busbar assembly 200 Busbar 300 fire-resistant silicone layer 400 fiberglass layers 400S glass fiber strand 1000 battery packs 1100 Pack Frame 1200 battery module 1300 BDU Module 1400 BMS Module

Claims

1. bus bars for guiding electrical connections within the battery pack; and a glass fiber layer including glass fibers and encasing the bus bar; A busbar assembly comprising at least one glass fiber forming a glass fiber strand, the surface of the glass fiber strand being coated with a refractory silicone layer.

2. The busbar assembly of claim 1 , wherein the fiberglass layer includes voids formed between the fiberglass strands.

3. The busbar assembly according to claim 1 , wherein the glass fiber layer is a woven fabric made of the glass fiber strands.

4. The busbar assembly according to claim 1 , wherein the glass fiber layers are formed by cross-stacking the glass fiber strands layer by layer.

5. The busbar assembly of claim 1 , wherein the refractory silicone layer comprises a silicone material that is ceramified at high heat.

6. At least one busbar assembly according to claim 1; Battery module; a BDU (Battery Disconnect Unit) module for controlling the electrical connection of the battery module; and a BMS (Battery Management System) module that monitors and controls the operation of the battery module; At least one of the busbar assemblies electrically connects at least one of the battery modules, the battery modules and the BDU module, the battery modules and the BMS module, or the BDU module and the BMS module.

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