Fireproof busbar and battery pack equipped with same

Abstract

The present invention provides a battery pack including the fireproof busbar, the fireproof busbar comprising: a busbar conductor portion; a fireproof silicone coating layer that covers the busbar conductor portion except for both ends and that is ceramicized at a high temperature to support the busbar conductor portion; and a protective layer that covers the fireproof silicone coating layer, the fireproof silicone coating layer having a built-in metal sheet that reinforces the structural rigidity of the fireproof silicone coating layer.

Description

[Technical field]

[0001] The present invention relates to a fire-resistant bus bar and a battery pack including the same.

[0002] More specifically, the present invention relates to a fire-resistant bus bar and a battery pack that are provided with a fire-resistant silicone coating layer that is ceramicized at high temperatures and a protective layer that encases the coating layer, and that can maintain insulating and airtight properties even at high temperatures that could cause fire inside the battery pack.

[0003] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0139401 dated October 26, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference. [Background technology]

[0004] A battery pack applied to an electric vehicle or the like has a structure in which a number of battery modules, each including a plurality of secondary batteries, are connected in series or parallel to obtain high output. The secondary battery can be repeatedly charged and discharged by electrochemical reactions between components including positive and negative electrode current collectors, separators, active materials, electrolytes, etc.

[0005] A bus bar is used to electrically connect the battery modules, and the bus bar is used to electrically connect terminal portions of adjacent battery modules or to connect the battery module to an external electric device.

[0006] FIG. 1 is a schematic diagram showing a conventional busbar structure.

[0007] As shown in the figure, a conventional busbar 1 is composed of a busbar conductor portion 10 and a coating layer 20 that encases the busbar conductor portion. The busbar conductor portion 10 is, for example, a high-purity copper conductor portion such as C1100 or a metal conductor portion such as aluminum. The coating layer 20 is made of a material such as ordinary silicone rubber or epoxy. The coating layer 20 covers the main body of the busbar conductor portion 10 except for both end portions 11. Fastening holes 11a are arranged at both end portions 11 of the busbar conductor portion 10 for fastening to corresponding electrical connecting portions.

[0008] 2, the bus bar 1 electrically connects battery modules M installed in a battery pack. The bus bar 1 is installed in a through hole H of a partition wall W installed between battery modules M, and both ends 11 of an exposed metal conductor portion 10 of the bus bar 1 are connected to module terminal portions on both sides of the partition wall, respectively.

[0009] When the battery modules are electrically connected, for example, by the above-mentioned conventional bus bar in a battery pack, no problem occurs in the operation of the battery pack at normal temperatures where the battery pack normally operates.

[0010] However, when a fire breaks out inside a battery pack, the temperature of the flame is so high (500 to 800°C, or over 800°C, and in severe cases over 1000°C), that the silicone rubber and epoxy coating layers melt completely, exposing the busbar conductor to the outside. When this happens, the exposed busbar conductor comes into electrical contact with other metal parts of the pack, causing a short circuit, and the heat generated by the electrical short causes the flame to spread further.

[0011] In order to prevent thermal propagation, a bus bar using a mica sheet, glass fiber, or heat-resistant silicone (rubber) as the covering layer may be considered.

[0012] However, in the above-mentioned intense heat generation situation, the above-mentioned materials cannot sufficiently prevent heat diffusion. For example, ordinary heat-resistant silicone rubber has a heat resistance temperature of only 125 to 300°C and cannot effectively deal with the ignition situation inside the battery pack. In addition, the covering layer made of mica sheet or glass fiber does not have sufficient fire resistance.

[0013] Thus, recent battery packs are required to be designed in such a way that in the event of an internal fire, flames will not escape to the outside of the pack.

[0014] In addition, a design is required that can thermally and electrically insulate the busbar conductor from its surroundings even at high temperatures when a flame occurs.

[0015] In view of the above, it can be said that there is a demand for the development of a technology that can improve the insulating strength and ease of assembly while maintaining electrical insulating properties by providing fire resistance at high temperatures. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Korean Patent Publication No. 2022-0001228 Summary of the Invention [Problem to be solved by the invention]

[0017] The present invention provides a fire-resistant busbar that can maintain thermal and electrical insulation for as long as possible even in the event of a fire inside a battery pack.

[0018] The present invention also provides a battery pack including the above-mentioned fire-resistant bus bar. [Means for solving the problem]

[0019] The fireproof busbar of the present invention, which has been made to solve the above-mentioned problems, includes a busbar conductor portion, a fireproof silicone coating layer that covers a portion of the busbar conductor portion except for both ends and that is ceramicized at a high temperature to support the busbar conductor portion, and a protective layer that covers the fireproof silicone coating layer, wherein the fireproof silicone coating layer has a built-in metal sheet that reinforces the structural rigidity of the fireproof silicone coating layer.

[0020] The fire-resistant silicone can be ceramicized at a temperature of 500 to 1700°C.

[0021] The fire-resistant silicone can be made into a ceramic by sintering a silicone resin containing a silicone compound represented by the following chemical formula 1 and a metal oxide containing silicon oxide.

[0022]

number

[0023] In the above Chemical Formula 1, m and n are integers of 10 to 30, respectively.

[0024] The silicone resin and the metal oxide may be contained in a weight ratio of 1:0.5 to 1.5.

[0025] The silicon oxide-containing metal oxide may include one or more of pure silicon dioxide, silica, quartz, silica stone, tridymite, and keatite.

[0026] The metal sheet may be extended along the fire-resistant silicone coating layer surrounding the bus bar conductor portion and embedded in the fire-resistant silicone coating layer so as to surround the bus bar conductor portion.

[0027] A fire-resistant silicone coating layer is provided between the inner side of the metal sheet and the bus bar conductor portion, and a fire-resistant silicone coating layer is provided between the outer side of the metal sheet and the protective layer, and the fire-resistant silicone coating layers on the inner and outer sides of the metal sheet can be connected via through holes formed in the metal sheet.

[0028] The metal sheet may be molded with the fire resistant silicone coating layer.

[0029] The metal sheet has a plurality of through holes, and the fire-resistant silicone is injection molded onto the upper and lower surfaces of the metal sheet, so that the fire-resistant silicone is coated onto the upper and lower surfaces of the metal sheet and filled into the through holes, thereby forming the metal sheet and the fire-resistant silicone coating layer integrally.

[0030] The integrated metal sheet and fire-resistant silicone coating layer are processed into a tape, and the tape is wound around the bus bar conductor, whereby the bus bar conductor can be coated with the fire-resistant silicone coating layer.

[0031] The fire-resistant busbar of the present invention has the busbar conductor portions and the metal sheet disposed in a mold, the metal sheet enveloping the busbar conductor portions while being spaced apart from the busbar conductor portions, and a fire-resistant silicone coating layer including the metal sheet can cover the busbar conductor portions by insert injection molding in which the fire-resistant silicone is injected into the mold.

[0032] The protective layer may be made of fiberglass or mica material.

[0033] The fire-resistant bus bar may be a high-voltage bus bar that electrically connects high-voltage terminal portions of a plurality of battery modules.

[0034] A battery pack according to another aspect of the present invention may include a plurality of battery modules, fireproof partitions installed between the battery modules, the fireproof bus bars electrically connecting the battery modules, and a pack housing accommodating the battery modules and the fireproof partitions.

[0035] The fireproof partition may include a busbar installation through-hole or a busbar installation groove, the fireproof busbar may be seated in the busbar installation through-hole or the busbar installation groove, and both ends of the fireproof busbar may be electrically coupled to terminal portions of battery modules located on both sides of the fireproof partition. Effect of the Invention

[0036] The fire-resistant busbar of the present invention has a fire-resistant silicone coating layer that is ceramicized to support the busbar conductor portion instead of a coating layer that will not burn in the event of a flame breaking out inside the pack, and therefore can maintain its insulating and airtight properties even at high temperatures.

[0037] In addition, the fire-resistant silicone coating layer is provided with a metal sheet to reinforce the structural rigidity of the coating layer, thereby preventing deformation due to external forces, and the metal sheet maintains the insulation and shape of the busbar, and also performs the shielding function required for high voltage.

[0038] In addition, the fire-resistant busbar of the present invention includes a protective layer for protecting the fire-resistant silicone coating layer, and the protective layer serves as a primary fire-resistant wall while preventing the fire-resistant silicone coating layer from being directly exposed to flames, thereby enabling the fire-resistant busbar to maintain its overall shape and dimensions. [Brief description of the drawings]

[0039] [Figure 1] 1A and 1B are a schematic view and a cross-sectional view showing a conventional busbar structure. [Diagram 2] FIG. 1 is a schematic diagram showing a state in which battery modules are connected by a conventional bus bar. [Diagram 3]1A and 1B are perspective and cross-sectional views of a fire-resistant busbar according to an embodiment of the present invention; [Figure 4] FIG. 2 is a schematic diagram showing an example of a process for producing the fire-resistant busbar of the present invention. [Diagram 5] FIG. 4 is a schematic diagram showing another example of a process for producing the fire-resistant busbar of the present invention. [Figure 6] FIG. 1 is a schematic diagram showing an example of a battery pack structure in which the fire-resistant busbar of the present invention is installed. [Figure 7] FIG. 11 is a schematic diagram showing another example of a battery pack structure in which the fire-resistant busbar of the present invention is installed. [Figure 8] FIG. 2 is a side cross-sectional view showing a state in which the fire-resistant bus bar of the present invention is installed in a battery pack. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] Hereinafter, detailed configurations of the present invention will be described in detail with reference to the attached drawings and various embodiments. The embodiments described below are illustratively shown to facilitate understanding of the present invention, and the attached drawings are not drawn to actual scale to facilitate understanding of the invention, and the dimensions of some components may be exaggerated.

[0041] Since the present invention can be modified in various ways and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text, but this is not intended to limit the present invention to the specific disclosed forms, and it is understood that the present invention includes all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0042] [Fireproof busbar] The fireproof busbar of the present invention includes a busbar conductor portion, a fireproof silicone coating layer that covers a portion of the busbar conductor portion except for both ends and that is ceramicized at a high temperature to support the busbar conductor portion, and a protective layer that covers the fireproof silicone coating layer, and the fireproof silicone coating layer has a built-in metal sheet that reinforces the structural rigidity of the fireproof silicone coating layer.

[0043] The busbar conductor portion may be a normal metal conductor portion. That is, it may be made of a high purity tough pitch copper material of 99.9% or more, such as C1100, or may be manufactured from an aluminum material. That is, the busbar conductor portion of the present invention is not particularly limited as long as it is a metal material that can function as a busbar conductor for connecting electrical components. Both ends of the busbar conductor portion are electrically connected to corresponding electrical connection portions.

[0044] The fire-resistant silicone coating layer is a layer that coats the busbar conductor while wrapping the busbar conductor except for both ends. That is, the fire-resistant silicone coating layer coats the periphery of the central part of the busbar conductor except for both ends. The fire-resistant silicone coating layer is ceramicized at high temperature to support the busbar conductor. The fire-resistant silicone can be ceramicized at a temperature of 500 to 1700°C. The fire-resistant silicone of the present invention is distinguished from heat-resistant silicone having a heat-resistant temperature of less than 300°C in that the fire-resistant temperature is 500°C or higher. Heat-resistant silicone is a silicone resin or rubber composition having flexibility and pliability due to the characteristics of silicone, but is a material that does not burn or turns to ash at a high temperature of 500°C or higher. Therefore, there is a limit to its application to preventing short circuits of a battery pack during heat propagation or preventing heat propagation.

[0045] The fire-resistant silicone coating layer has a "fire-resistant" property of being ceramicized at high temperatures of 500°C or more, and therefore can maintain insulating properties and airtight properties within the battery pack even in the event of a flame.

[0046] In this manner, the fire-resistant busbar according to the present invention can realize high fire resistance by providing fire-resistant silicone inside as well as structural improvements.

[0047] The fire-resistant silicone is a composition mainly composed of silicone resin and metal oxide, and has softness and flexibility due to the characteristics of silicone at room temperature. It also has a certain elasticity, shows high impact resistance and insulation, and when exposed to high temperatures, it can form a silicone sintered body with a complex ceramic structure by sintering the silicone resin and metal oxide.

[0048] Specifically, the silicone resin contained in the fireproof silicone generates powdered silica when burned at high temperatures. The silica thus generated reacts with the metal oxide of the fireproof silicone to form a "eutectic mixture" at the edge of the metal oxide, thereby performing a bridging role between the silica and the metal oxide, so that it hardens at the ignition temperature and forms a condensed ceramic product when cooled. Such a ceramic body prevents short circuits or disconnections between conductors due to damage to the fireproof silicone coating layer even when an external mechanical impact is applied during a fire or moisture penetrates, and the busbar itself can perform its electrical function.

[0049] For this reason, the fire-resistant silicone according to the present invention comprises a silicone resin and a metal oxide.

[0050] The silicone resin is not particularly limited as long as it is a resin containing silicon (Si) in the molecule, but preferably contains a silicone compound represented by the following chemical formula 1 (hereinafter referred to as "silicone compound of chemical formula 1"):

[0051]

number

[0052] In the above Chemical Formula 1, m and n are integers of 10 to 30, respectively.

[0053] The silicone compound of formula 1 contains a methylsiloxane repeating unit and a vinyl group at the inside and end of the methylsiloxane repeating unit. The vinyl group is present not only at the end of the silicone compound of formula 1 but also inside the repeating unit, and plays a role in increasing the degree of polymerization of the silicone resin when exposed to high temperatures, thereby achieving better fire resistance than silicone compounds that do not contain vinyl groups.

[0054] In addition, the silicone compound of Chemical Formula 1 may have a weight average molecular weight adjusted to a specific range. The silicone compound of Chemical Formula 1 is a compound that forms the base of a silicone resin, and may affect the physical properties of the fireproof silicone at room temperature and high temperature depending on the weight average molecular weight of the silicone compound of Chemical Formula 1. For example, if the weight average molecular weight of the silicone compound of Chemical Formula 1 is excessively high, the viscosity of the silicone resin may increase and the reactivity during high-temperature sintering may decrease, and if the weight average molecular weight is significantly low, the elasticity and flexibility of the silicone resin at room temperature may decrease, and the manufacturing processability of the fireproof busbar may decrease, while there is a limit to the decrease in impact resistance, etc. Therefore, the silicone compound of Chemical Formula 1 according to the present invention may have a weight average molecular weight adjusted to 1,000 to 9,000 g / mol, specifically 3,000 to 8,000 g / mol, or 5,000 to 7,000 g / mol.

[0055] In addition, the metal oxide is a composition containing silicon oxide, and when exposed to high temperatures, it acts as a crystal nucleus and can play a role in forming a high density ceramic body together with the silicone resin described above.

[0056] Such metal oxides may include one or more of silicon dioxide, silica, quartz, silica stone, tridymite, and keatite. The metal oxides include minerals such as quartz containing silicon dioxide (SiO2) as a main component as well as pure silicon dioxide (SiO2), and therefore are not only highly economical but also have a high melting point (high fire resistance) and a high sintering degree, and can exhibit excellent electrical insulation performance. In particular, silicon dioxide, silica, quartz, etc. can improve various performances during the sintering process, induce easy melting and molding of the fireproof silicone, and reduce defects that may occur in the ceramic body.

[0057] The metal oxide may have a crystal structure that increases fire resistance, insulation, mechanical strength, etc., when sintered with the silicone resin. Such metal oxide is in a powder form, and although there is no particular limitation, one having a size of 200 μm or less, specifically, for example, 0.1 μm to 200 μm or 0.1 μm to 100 μm can be used.

[0058] The silicone resin may further include a silicone compound represented by the following formula 2 (hereinafter, referred to as "silicone compound of formula 2"). The silicone compound of formula 2, together with the silicone compound of formula 1, participates in the sintering of metal oxide at high temperatures to form a silicone sintered body:

[0059]

number

[0060] In the above Chemical Formula 2, p is an integer of 10-30.

[0061] The silicone compound of Formula 2 increases the flexibility of the fireproof silicone at room temperature, while at the same time inducing the termination of sintering of the silicone resin by dehydration condensation with the silicone compound of Formula 1 during sintering, thereby terminating the reaction of forming a ceramic body.

[0062] For this reason, the silicone compound of Formula 2 may be used in an amount of less than 10 parts by weight, specifically 0.5 to 9 parts by weight, 1 to 6 parts by weight, or 2 to 5 parts by weight, based on 100 parts by weight of the fire-resistant silicone.

[0063] In addition, the fireproof silicone may contain a certain ratio of silicone resin and metal oxide to realize high elasticity at room temperature and to rapidly form a ceramic body when exposed to high temperature.

[0064] Specifically, the weight ratio of the silicone resin to the metal oxide in the fireproof silicone may be 1:0.5-1.5, specifically 1:0.8-1.2. If the weight ratio of the metal oxide is less than 0.5, it is difficult to obtain a ceramic structure having a high density crystal structure at high temperatures, and there is a problem that fire resistance and mechanical strength are not sufficiently realized. In addition, if the weight ratio of the metal oxide exceeds 1.5, the flexibility of the fireproof silicone at room temperature is reduced, and there is a limit to good handling.

[0065] As one example, the fireproof silicone of the present invention may contain 35 to 50% by weight of a silicone compound of Chemical Formula 1, 16 to 32% by weight of quartz, 10 to 27% by weight of silicon dioxide, and 1 to 6% by weight of a second silicone compound of Chemical Formula 2, and in some cases, may further contain a predetermined solvent to improve processability during production.

[0066] As described above, the fire-resistant silicone of the present invention is cured and ceramicized by sintering the silicone resin and metal oxide at 500° C. or higher. It can also be ceramicized up to 1700° C., and theoretically can maintain partial ceramicization even at temperatures above 1700° C. However, if the temperature exceeds 1700° C., the ceramicization time is shortened and the required fire resistance in the battery pack may not be maintained.

[0067] The fire-resistant silicone has rubber-like properties, including flexibility, softness, and elasticity, before being ceramified, as described above, so that the fire-resistant silicone coating layer can be easily injection molded or coated onto the busbar conductor, as described below.

[0068] The fireproof silicone coating layer has flexibility before being ceramized, and can flexibly follow deformation of the busbar conductor. Therefore, when the fireproof busbar of the present invention is installed in a battery pack, even if there is a slight assembly tolerance, it can be easily accommodated, improving assembly. For example, when a battery module is fastened to a battery pack by bolting, if the busbar conductor connected to the battery module flows or is slightly twisted, the fireproof silicone coating layer can absorb such flow or twist. In addition, even if the battery pack vibrates due to vibration of the electric vehicle, the fireproof silicone coating layer can naturally absorb the vibration.

[0069] On the other hand, when the fireproof silicone is ceramified at high temperature, the thermal and electrical insulation is maintained, but the mechanical strength is somewhat weakened, and there is a risk of cracking due to external force. In the present invention, in order to structurally improve the rigidity of such a fireproof silicone coating layer, a metal sheet is embedded in the fireproof silicone coating layer, and a protective layer is provided that encases the fireproof silicone coating layer.

[0070] The protective layer is a layer that surrounds the exterior of the fireproof silicone coating layer and protects the fireproof silicone coating layer from being directly exposed to flames. That is, the protective layer primarily serves as a fireproof wall. When the fireproof silicone coating layer is ceramicized, the protective layer encases the ceramicized coating layer and maintains the overall shape and dimensions of the coating layer.

[0071] The protective layer may be made of, for example, glass fiber or mica material that has both insulating and heat resistance. That is, a glass fiber tape or mica tape may be wrapped around the outside of the fire-resistant silicone coating layer to prevent the fire-resistant silicone coating layer from being exposed to the outside. However, the protective layer is not limited to this, and the protective layer may be made of other materials that have excellent insulating or heat resistance.

[0072] In order to reinforce the rigidity of the fire-resistant silicone coating layer, a metal sheet is embedded in the coating layer. The metal sheet is embedded in the fire-resistant silicone coating layer and serves as a kind of skeleton. The fire-resistant silicone coating layer has flexibility and pliability before being ceramized, and may be structurally fragile. For example, even if the fire-resistant silicone coating layer is coated or applied to the busbar conductor portion and hardened, it may be deformed due to the characteristics of the material. However, when a metal sheet is provided in the fire-resistant silicone coating layer, the metal sheet serves as a skeleton and serves to structurally support the coating layer.

[0073] In particular, when the fire-resistant silicone coating layer is ceramified at high temperatures, it may become brittle and its mechanical strength may be weakened. In this case, the metal sheet structurally supports the ceramified silicone, thereby preventing deformation of the coating layer due to external forces. This allows the shape of the fire-resistant silicone coating layer to be maintained, and the insulating function of the coating layer to be stably maintained. In addition, since the metal sheet is made of metal, the metal sheet can also perform an electromagnetic wave shielding function, for example, when the fire-resistant busbar is used as a high-voltage busbar. Therefore, the fire-resistant busbar of the present invention having the built-in metal sheet can be suitably used as a high-voltage busbar.

[0074] The metal sheet may be made of one of the following metals, for example: aluminum, steel, or stainless steel, but is not limited thereto, and may be made of other suitable metals that can reinforce the rigidity of the fireproof silicone coating layer and have an electromagnetic wave shielding function.

[0075] Specific configurations of the fire-resistant busbar and metal sheet will be described in detail in the following embodiments.

[0076] (First embodiment) FIG. 3 is a perspective view and a cross-sectional view of a fire-resistant busbar according to an embodiment of the present invention.

[0077] As shown in the figure, the fire-resistant busbar 100 has a busbar conductor portion 110 at its innermost portion, and a covering portion P is provided on the busbar conductor portion 110 except for both end portions 111. Both end portions 111 of the busbar conductor portion 110 are exposed to the outside and have fastening holes 111a for coupling with corresponding electrical connecting portions (e.g., terminal portions).

[0078] The covering portion P includes a fire-resistant silicone covering layer 120 that covers the bus bar conductor portion 110, and a protective layer 130 that covers the fire-resistant silicone covering layer 120. The fire-resistant silicone covering layer 120 has a metal sheet 140 built therein.

[0079] The fireproof silicone coating layer 120 may be transparent or opaque depending on the detailed configuration of the coating layer. In the perspective view of FIG. 3, the fireproof silicone coating layer 120 is shown in a transparent state in order to clearly show the shape of the embedded metal sheet 140.

[0080] As shown in FIG. 3, the metal sheet 140 extends along the fireproof silicone coating layer 120 that covers the bus bar conductor portion 110, and is embedded in the fireproof silicone coating layer 120 to cover the bus bar conductor portion 110. That is, the metal sheet 140 extends along the fireproof silicone coating layer 120 like a skeleton. The thickness of the metal sheet 140 may be suitably determined depending on the thickness of the coating layer 120, the composition and physical properties of the fireproof silicone coating layer 120, etc. Also, in the case of a high voltage bus bar, the thickness of the metal sheet 140 may be set to a thickness required for electromagnetic wave shielding. For example, the metal sheet 140 may be manufactured to a thickness of 0.3 to 3 mm.

[0081] It is preferable that the metal sheet 140 and the bus bar conductor portion 110 are spaced apart for insulation. In this case, as shown in the cross-sectional view of FIG. 3, the fireproof silicone coating layer 120 is disposed (filled) between the metal sheet 140 and the bus bar conductor portion 110. In addition, the fireproof silicone coating layer 120 is provided between the outer side of the metal sheet 140 and the protective layer 130. Therefore, the fireproof silicone coating layer 120 is located on the inner side and the outer side of the metal sheet 140 with the metal sheet 140 as a boundary. In this case, the fireproof silicone coating layer 120 on the inner side and the outer side of the metal sheet 140 may be blocked by the metal sheet 140. However, it is more preferable that the fireproof silicone coating layer 120 on the inner side and the outer side of the metal sheet 140 are connected to each other via the metal sheet 140 in order to make the bond between the metal sheet 140 and the fireproof silicone coating layer 120 stronger.

[0082] For this purpose, as shown in FIG. 3, a through hole 141 may be disposed in the metal sheet 140. In this case, the inner and outer fireproof silicone coating layers 120 of the metal sheet 140 may be connected to each other through the through hole 141. In this case, the metal sheet 140 and the inner and outer fireproof silicone coating layers 120 may be more firmly bonded together, so that the structural rigidity of the fireproof silicone coating layer 120 may be further improved. Therefore, when the fireproof silicone coating layer 120 is ceramized, the metal sheet 140 may more firmly support the coating layer 120. The through hole 141 may be formed in a plurality of pieces spaced apart on the metal sheet 140. The through hole 141 may have a circular, rectangular, or other shape, and the size of the through hole 141 may also be suitably selected.

[0083] The metal sheet 140 may be molded together with the fire-resistant silicone coating layer 120. The molding of the fire-resistant silicone coating layer 120 or the manufacturing process of the fire-resistant busbar 100 of the present invention will be described in detail in the following embodiments.

[0084] Second embodiment FIG. 4 is a schematic diagram showing an example of a process for producing the fire-resistant busbar 100 of the present invention.

[0085] In this embodiment, the metal sheet 140 is molded together with the fire resistant silicone coating layer 120 .

[0086] The metal sheet 140 has a plurality of circular through holes 141, for example. The fireproof silicone may be injected toward the metal sheet 140 from nozzles 151 of the fireproof silicone storage tanks 150 located at the top and bottom of the metal sheet 140. As described above, the fireproof silicone may be a mixture of silicone resin and metal oxide, and may be in the form of a coating liquid or slurry having fluidity by being contained in a predetermined solvent. When the fireproof silicone coating liquid is injected onto the top and bottom surfaces of the metal sheet 140, the top and bottom surfaces of the metal sheet 140 are coated with the fireproof silicone, and the through holes 141 are filled with the fireproof silicone at the same time. In this case, the fireproof silicone on the top and bottom surfaces of the metal sheet 140 are integrally connected through the through holes 141 of the metal sheet 140 as shown in the drawing. The injection of the fireproof silicone may be performed in a certain mold, so the metal sheet 140 and the fireproof silicone may be integrally manufactured by injection molding. The fire-resistant silicone coating layer 120 coated on the metal sheet 140 may have physical properties similar to those of silicone rubber after undergoing a drying and predetermined curing process.

[0087] The integrated metal sheet 140 and fireproof silicone coating layer 120 can be processed into a tape shape as shown in Fig. 4. By winding such a fireproof silicone coating tape around the busbar conductor portion 110, the busbar conductor portion 110 can be coated with the fireproof silicone coating layer 120. Next, by winding a protective layer 130, for example, a glass fiber tape, on the fireproof silicone coating layer 120, the fireproof busbar 100 of the present invention can be manufactured.

[0088] The protective layer 130 tape may be wound after the fire-resistant silicone coated tape is wound around the busbar conductor portion 110, or as shown in Fig. 4, the protective layer 130 tape may be attached to the fire-resistant silicone coated tape in advance to produce the coated portion P. In this case, the fire-resistant busbar 100 can be manufactured at one time by winding the coated portion tape around the busbar conductor portion 110, which has the advantage of shortening the manufacturing process.

[0089] In the present embodiment, the covering portion P is formed in a tape shape, and the tape of the covering portion P can be repeatedly wound around the bus bar conductor portion 110 as necessary, so that the insulation property and fire resistance can be further enhanced. In addition, it is convenient to adjust the number of windings of the covering portion tape to adjust the insulation property and fire resistance to meet the design values.

[0090] However, in the case of this embodiment, when processing into a tape, the flexibility of the metal sheet 140 may become a problem. If the thickness of the metal sheet 140 is made very thin, the metal sheet 140 may bend following the bending of the fireproof silicone coating layer 120, but if the thickness of the metal sheet 140 is relatively thick, it may be difficult to wind it into a tape. The following embodiment solves such manufacturing difficulties by processing the shape of the metal sheet 140 in advance.

[0091] Third embodiment FIG. 5 is a schematic diagram showing another example of a process for producing the fire-resistant busbar 100 of the present invention.

[0092] In this embodiment, the fire-resistant busbar 100 is manufactured by a type of insert injection molding method in which the metal sheet 140 and the busbar conductor portion 110 are placed in a mold in advance, and fire-resistant silicone is injected into the mold.

[0093] The busbar conductor portion 110 and the metal sheet 140 are disposed in the upper and lower molds 160, 160' for insert injection molding as shown in FIG. 5, whereby the metal sheet 140 may be separated from the busbar conductor portion 110 while enveloping the busbar conductor portion 110. Then, a coating liquid or slurry of fireproof silicone is injected through an injection port 161 provided in the molds 160, 160'. In this case, the fireproof silicone is filled between the metal sheet 140 and the busbar conductor portion 110 through the through-holes 141 of the metal sheet 140, and is also filled between the outside of the metal sheet 140 and the molds 160, 160'. When the molds are removed after a predetermined drying and curing process, a coating layer having the busbar conductor portion 110 embedded therein can be obtained as shown in FIG. 3. Then, a tape of the protective layer 130 such as a glass fiber tape or a mica tape is wound on the coating layer to obtain the fireproof busbar 100 of the present invention.

[0094] In this embodiment, since the metal sheet 140 is bent in advance to wrap the bus bar conductor portion 110, a relatively thick metal sheet 140 can be easily used. In addition, since the fireproof silicone can be filled simultaneously on the inside and outside of the metal sheet 140 through the through holes 141 of the metal sheet 140, the manufacturing process is greatly simplified. In addition, the thickness of the fireproof bus bar covering layer 120 can be easily adjusted depending on the size of the mold.

[0095] [Battery pack] FIG. 6 is a schematic diagram showing an example of a battery pack structure in which a fire-resistant busbar of the present invention is installed, FIG. 7 is a schematic diagram showing another example of a battery pack structure in which a fire-resistant busbar of the present invention is installed, and FIG. 8 is a side cross-sectional view showing the state in which the fire-resistant busbar of the present invention is installed in a battery pack.

[0096] The fire-resistant busbar 100 of the present invention includes the fire-resistant silicone coating layer 120 that is ceramicized at high temperature, the protective layer 130 that wraps the fire-resistant silicone coating layer 120 to maintain its shape, and the metal sheet 140 that reinforces the rigidity of the coating layer. Therefore, when applied to a battery pack in which internal fire may occur, the safety of the battery pack can be significantly improved.

[0097] The fire-resistant busbar 100 may be used, for example, to electrically connect a plurality of battery modules housed in a battery pack to each other. In this case, the fire-resistant busbar 100 may electrically connect terminal portions of adjacent battery modules. Alternatively, the fire-resistant busbar 100 may be used to connect a battery module to an external electric device.

[0098] In particular, the high voltage terminal of the battery module generates relatively high heat due to high current. As a result, when a fire occurs inside the pack, high heat may be concentrated on the high voltage terminal. Therefore, the fire-resistant busbar 100 of the present invention is suitable for use as a high voltage busbar that electrically connects high voltage terminals of a plurality of battery modules. In addition, the fire-resistant busbar 100 includes the metal sheet 140 having an electromagnetic wave shielding function, and is therefore more suitable for use as a high voltage busbar that requires high electromagnetic wave shielding.

[0099] The battery pack 1000 of the present invention may include a plurality of battery modules 200, fire prevention partitions 300 installed between the battery modules, the above-described fireproof busbar 100 that electrically connects the battery modules, and a pack housing 400 that accommodates the battery modules and the fire prevention partitions.

[0100] 6, a plurality of battery modules 200 are accommodated in a pack housing 400. The battery module 200 includes a cell stack (not shown) in which a plurality of battery cells are stacked, and cell leads of different polarities are led out from the battery cells of the cell stack. The cell leads are electrically connected to a bus bar, such as a terminal bus bar or an inter bus bar, or to a bus bar. The fireproof bus bar 100 according to the present invention may be applied to electrically connect the plurality of battery modules.

[0101] Meanwhile, Figs. 6 and 7 disclose a typical battery module 200 in which a module housing completely surrounds the top, bottom, left and right sides of a battery cell stack. However, the present invention is not limited thereto, and the fire-resistant busbar 100 of the present invention may be applied to, for example, a battery module having a module housing of a moduleless structure in which at least one of the top, bottom, left and right sides of the cell stack is open, or a battery cell block in which the entire top, bottom, left and right sides of the cell stack are open. In this way, a cell block or a battery module in which all or part of the module housing is omitted may be installed in a battery pack to configure a so-called cell-to-pack battery pack. The fire-resistant busbar 100 of the present invention may be used for electrically connecting the cell block or the module-less battery module installed in such a battery pack of the cell-to-pack structure.

[0102] In order to prevent flame propagation between adjacent modules, the battery pack 1000 may include a fire prevention partition 300 installed between the battery modules. The fire prevention partition 300 may be made of a metal material to ensure rigidity. The fire prevention partition 300 serves to prevent flame propagation to an adjacent module when a fire occurs in one module. In this case, the fire prevention partition 300 may be provided with a busbar installation through hole 310 or a busbar installation groove 320. FIG. 6 shows that the fire prevention partition 300 is provided with a busbar installation through hole 310, and FIG. 7 shows that the fire prevention partition 300 is provided with a busbar installation groove 320. In terms of fire prevention and airtightness, a partition provided with the busbar installation through hole 310 as shown in FIG. 6 is advantageous. The busbar installation groove 320 in FIG. 7 has an open upper portion, which is advantageous for performing busbar installation and electrical connection work of the busbar.

[0103] The fireproof busbar 100 may be seated in the busbar installation through-hole 310 or the busbar installation groove 320. At this time, both ends 111 of the busbar conductor portion 110 may be electrically coupled to terminal portions 210 and 220 of the battery modules 200 located on both sides of the fire prevention partition 300.

[0104] 8 shows how the fireproof busbar 100 electrically connects the battery modules 200 in the battery pack 1000. A fireproof partition 300 is located between adjacent battery modules 200, and the fireproof partition has a busbar installation through-hole 310. The fireproof busbar 100 of the present invention is inserted into the through-hole.

[0105] Meanwhile, in the case where a fire occurs in the battery pack 1000, the fireproof busbar of the present invention forms a dense sintered body by ceramicizing the fireproof silicone coating layer 120 surrounding the busbar conductor portion 110. That is, unlike conventional heat-resistant silicone, which does not burn or turn to ash at a high temperature of 500°C or more, the fireproof silicone coating layer 120 is ceramicized and maintains its shape. As a result, the fireproof silicone coating layer 120 stably supports the busbar conductor portion 110 even when a fire occurs. At this time, the metal sheet 140 reinforces the rigidity of the fireproof silicone coating layer 120 to prevent the coating layer 120 from cracking. In addition, the protective layer 130 prevents the fireproof silicone coating layer 120 from directly contacting the flame, thereby preventing deformation of the fireproof silicone, and further strengthens the insulation and fire resistance.

[0106] [Experimental Example]

[0107] (Experimental Example 1) A fireproof silicone consisting of 50 parts by weight of the silicone compound of the above chemical formula 1, 20 parts by weight of quartz, and 30 parts by weight of pure silicon dioxide was applied to a thickness of 0.5 to 3 mm. 2 A copper busbar conductor having a predetermined cross-sectional area selected from the range of cross-sectional areas was coated with a predetermined thickness on the portion excluding both ends. A 0.18 mm thick glass fiber tape (product name: AGTWO) manufactured by SWECO was wound twice around the above-mentioned fire-resistant silicone coated busbar to manufacture the fire-resistant silicone coated busbar of Example 1.

[0108] The length of the busbar conductor portion and the exposed length of both ends were set to be the same as in Example 1, and a glass fiber tape of AGTWO was wound around the center of the busbar conductor portion to produce a busbar of Comparative Example 2. The coating thickness of the wound glass fiber tape was set to be approximately the same as the coating thickness of Example 1.

[0109] For the busbar of Comparative Example 2, a mica tape made of phlogopite mica, which is a natural mica, was wound around the center of the busbar conductor, and then a glass fiber tape made of AGTWO was wound on top of that. The length of the busbar conductor and the exposed length of both ends were the same as those of Example 1 and Comparative Example 1.

[0110] In order to test the insulation characteristics (insulation maintenance performance) in the event of a fire, a copper wire was wound around the coating of the busbars of Example 1 to Comparative Example 2 with the same number of turns, and one end of the copper wire at the outermost part of the coating was connected to the negative terminal of a voltage resistance tester, and one end of the busbar conductor was connected to the positive terminal of the voltage resistance tester. With a voltage of 1000V applied to the busbars by the voltage resistance tester, the entire surface of the busbar was uniformly heated with a large torch with a flame temperature of 1100 to 1150°C.

[0111] Under the above voltage and heating temperature conditions, the insulation failure time until the insulation state is broken down, i.e., a short circuit occurs, was measured, and the measurement results are shown in Table 1 below.

[0112] [Table 1]

[0113] As shown in Table 1 above, the busbar having the coating layer according to the present invention had the longest insulation failure time, and showed a large difference from Comparative Example 1 and Comparative Example 2 in terms of insulation failure time.

[0114] Therefore, it can be seen that the insulating properties of the fireproof busbar of the present invention having the above-mentioned fireproof silicone coating layer and protective layer are very excellent. In Example 1, the insulating performance was tested without a metal sheet, and it can be said that it is clear that the insulating performance against high external temperatures is further improved when a metal sheet is embedded in the fireproof silicone coating layer. In addition, when a metal sheet is installed, the mechanical strength of the ceramicized fireproof silicone coating layer is superior, and an electromagnetic wave shielding function can be additionally obtained.

[0115] (Experimental Example 2) The weight ratio of the silicone compound of the above Chemical Formula 1 and the weight ratio of the metal oxide were varied to prepare fireproof silicones having the compositions shown in Table 2 below.

[0116] Under the same conditions as in Experimental Example 1, the copper busbar conductor was coated with a fire-resistant silicone coating layer to a predetermined thickness, and AGTWO glass fiber tape was wound on the fire-resistant silicone coating layer.

[0117] A copper wire was wound on the fireproof silicone coating layer under the same conditions as in Experimental Example 1, and connected to a voltage tester. With voltage applied, it was heated with a large torch under the same conditions as in Experimental Example 1, and the insulation failure time was measured. The measurement results are shown in Table 2 below.

[0118] [Table 2]

[0119] In the above Examples 1 to 5, the weight ratio of the silicone compound to the metal oxide was 1:1, 1:0.5, 1:1.5, 1:0.4, and 1:1.6.

[0120] All the examples have a much longer insulation fail time than the comparative examples 1 and 2. However, in the case of Example 4, in which the weight ratio is less than 0.5, the insulation fail time is somewhat shorter. This is believed to be due to the fact that the metal oxide is insufficient, resulting in a somewhat insufficient generation of a ceramic structure having a high density crystal structure at high temperatures.

[0121] In the case of Example 5 in which the weight ratio was 1.6, the insulation failure time was sufficiently long, but the metal oxide was excessive, reducing the flexibility of the fire-resistant silicone at room temperature, making it difficult to conform to and cover the bus bar conductors.

[0122] The present invention has been described in detail above with reference to the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments, etc. in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0123] 100: Fireproof busbar 110: Busbar conductor section 120: Fire-resistant silicone coating layer 130: Protective layer 140: Metal sheet 141:Through hole 150: Fireproof silicone storage tank 160, 160': Upper and lower dies 200: Battery module 210, 220: Terminal section 300: Bulkhead for flame prevention 310: Busbar installation through hole 320: Busbar installation groove 400: Pack housing 1000: Battery pack

Claims

1. A bus bar conductor portion; a fire-resistant silicone coating layer that covers the bus bar conductor portions except for both ends and that is ceramicized at a high temperature to support the bus bar conductor portions; a protective layer that encases the fire-resistant silicone coating layer; The fire-resistant silicone coating layer has an embedded metal sheet that reinforces the structural rigidity of the fire-resistant silicone coating layer.

2. 2. The fire resistant busbar of claim 1, wherein the fire resistant silicone coating layer ceramizes at a temperature of 500-1700°C.

3. The fire-resistant silicone coating layer is ceramicized by sintering a silicone resin containing a silicone compound represented by the following chemical formula 1 and a metal oxide containing silicon oxide: [0010] 2. The fire-resistant busbar according to claim 1, wherein in the formula 1, m and n are each an integer of 10 to 30.

4. The fire-resistant busbar according to claim 3, wherein the silicone resin and the metal oxide are contained in a weight ratio of 1:0.5 to 1.

5.

5. 4. The fire-resistant busbar of claim 3, wherein the metal oxide containing silicon oxide comprises one or more of pure silicon dioxide, silica, quartz, silica stone, tridymite and keatite.

6. The fire-resistant busbar according to claim 1 , wherein the metal sheet is extended along the fire-resistant silicone coating layer surrounding the busbar conductor portion and is embedded in the fire-resistant silicone coating layer so as to surround the busbar conductor portion.

7. a fire-resistant silicone coating layer is provided between the inner side of the metal sheet and the bus bar conductor portion; a fire-resistant silicone coating layer is provided between the outer side of the metal sheet and the protective layer; 7. The fire-resistant busbar according to claim 6, wherein the inner and outer fire-resistant silicone coating layers of the metal sheet are connected via through holes formed in the metal sheet.

8. The fire resistant busbar of claim 1 , wherein the metal sheet is molded with the fire resistant silicone coating layer.

9. the metal sheet has a plurality of through holes; 9. The fire-resistant busbar according to claim 8, wherein the fire-resistant silicone is injection-molded onto the upper and lower surfaces of the metal sheet, so that the fire-resistant silicone is coated onto the upper and lower surfaces of the metal sheet and filled into the through-holes, thereby forming the metal sheet and the fire-resistant silicone coating layer integrally.

10. 10. The fire-resistant busbar according to claim 9, wherein the integrated metal sheet and the fire-resistant silicone coating layer are processed into a tape, and the tape is wound around the busbar conductor portion, thereby covering the busbar conductor portion with the fire-resistant silicone coating layer.

11. the bus bar conductor portion and the metal sheet are disposed in a die, the metal sheet enveloping the bus bar conductor portion while being spaced apart from the bus bar conductor portion; 9. The fire-resistant busbar according to claim 8, wherein the busbar conductor portions are coated with a fire-resistant silicone coating layer comprising the metal sheet by insert injection molding in which fire-resistant silicone is injected into the mold.

12. The fire resistant busbar according to claim 1 , wherein the protective layer is made of a glass fiber or mica material.

13. The fire-resistant busbar according to claim 1 , wherein the fire-resistant busbar is a high-voltage busbar that electrically connects high-voltage terminal portions of a plurality of battery modules.

14. A plurality of battery modules; a fire prevention partition installed between the battery modules; A fire-resistant busbar according to any one of claims 1 to 13, electrically connecting the battery modules; A battery pack including the battery module and a pack housing that houses a flame-prevention partition.

15. The fire prevention partition has a bus bar installation through hole or a bus bar installation groove, The fireproof busbar is seated in the busbar installation through-hole or the busbar installation groove, The battery pack according to claim 14 , wherein both ends of the fire-resistant bus bar are electrically coupled to terminals of battery modules located on both sides of the fire prevention partition.

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