Fireproof busbar cap and battery pack equipped with same

Abstract

A fireproof bus bar cap according to the present invention is a bus bar cap for covering a bus bar and an electrical connection part coupled to the bus bar, the bus bar cap having an insertion space for a fastening member for fastening the bus bar and the electrical connection part therebetween, the bus bar cap including a fireproof silicone cap body which is ceramicized at high temperature, and a protective layer which covers the fireproof silicone cap body. Also, a battery pack according to the present invention includes the fireproof bus bar cap.

Description

[Technical field]

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

[0002] More specifically, the present invention relates to a fire-resistant bus bar cap and a battery pack equipped with the same, in which the cap body is made of fire-resistant silicone that becomes ceramic at high temperatures and has a protective layer that covers the cap body, thereby enabling the cap to maintain its 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. 10-2022-0139407 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 assembly structure of a bus bar and a cap.

[0007] As shown in the figure, a conventional busbar 10 is composed of a busbar conductor portion 11 and a coating layer 12 that encases the busbar conductor portion. The busbar conductor portion is, for example, a high-purity copper conductor portion such as C1100 or a metal conductor portion such as aluminum. The coating layer is made of a material such as ordinary silicone rubber or epoxy. Conventionally, a cap 20 has been attached to the coating layer 12 of the busbar 10 using a wear-resistant tape 30 or the like. The cap is formed separately so that it can be opened and closed freely when fastening members are fastened to fastening holes 11a at both ends of the busbar 10 to connect the busbar 10 to other electrical connecting portions.

[0008] However, the cap 20 is made of a soft rubber cap, which has poor insulation and is vulnerable to impact. In particular, when the conventional bus bar is used to electrically connect components inside a battery pack, if a fire occurs inside the battery pack, the temperature of the fire is so high (500 to 800°C, or more than 800°C, and in severe cases, more than 1000°C), that the rubber cap melts and the bus bar and electrical connection parts are exposed to the outside. When this happens, the exposed bus bar conductor part electrically contacts other metal parts inside the pack, causing a short circuit, and the heat generated by the electrical short circuit causes the flame to spread further.

[0009] 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.

[0010] In addition, a design is required that can thermally and electrically insulate the bus bar conductors and the electrical connectors connected thereto from the surroundings even at high temperatures when a flame breaks out inside the battery pack.

[0011] 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]

[0012] [Patent Document 1] Korean Patent Publication No. 2022-0001228 Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention provides a fire-resistant busbar cap that can maintain thermal and electrical insulation for as long as possible even in the event of a fire inside a battery pack.

[0014] The present invention also provides a battery pack including the above-mentioned fire-resistant bus bar cap. [Means for solving the problem]

[0015] The fireproof bus bar cap of the present invention, which solves the above problems, is a bus bar cap that covers a bus bar and an electrical connection part coupled to the bus bar, the bus bar cap having an insertion space therein for an insertion member that fastens the bus bar and the electrical connection part, the bus bar cap including a fireproof silicone cap body that is ceramicized at high temperatures, and a protective layer that covers the fireproof silicone cap body.

[0016] The fire-resistant silicone can be ceramicized at a temperature of 500 to 1700°C.

[0017] 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.

[0018] [Chemical formula 1]

number

[0019] In the above Chemical Formula 1, m and n are integers of 10 to 30, respectively.

[0020] The silicone resin and the metal oxide may be contained in a weight ratio of 1:0.5 to 1.5.

[0021] The silicon oxide-containing metal oxide may include one or more of pure silicon dioxide, silica, quartz, silica stone, tridymite, and keatite.

[0022] The protective layer can be a fiberglass layer or a mica layer.

[0023] The protective layer may be provided on an inner peripheral surface of the fastening member insertion space of the fireproof silicone cap body.

[0024] The fire-resistant silicone cap body may include a base portion covering a side surface of the bus bar or a side surface of the bus bar and an electrical connection portion, and a fastening member insertion portion extending upward from the base portion, having an insertion space for the fastening member therein, and covering an upper surface of the bus bar and an electrical connection portion.

[0025] A screw groove corresponding to the thread of the fastening member may be provided along the inner peripheral surface of the fireproof silicone cap body having the insertion space for the fastening member.

[0026] A screw fastening member may be coupled to the fastening member in the insertion space of the fastening member.

[0027] The threaded connection member can be integrally connected to the fire-resistant bus bar cap by insert injection molding, in which the threaded connection member is inserted into a mold and the fire-resistant silicone is injection molded.

[0028] A battery pack according to another aspect of the present invention includes a plurality of battery modules, a fire prevention partition installed between the battery modules, a bus bar electrically connecting the battery modules, a fireproof bus bar cap according to any one of claims 1 to 10 covering an electrical connection portion between the battery modules and the bus bar, and a pack housing accommodating the battery modules and the fire prevention partition.

[0029] the fire-prevention partition has a bus bar installation through hole or a bus bar installation groove, and the bus bar is seated in the bus bar installation through hole or the bus bar installation groove; Both ends of the bus bar may be electrically coupled to terminals of the battery modules located on both sides of the fire prevention partition, and the fireproof bus bar cap may cover electrical connections between the both ends and the terminals. Effect of the Invention

[0030] The fire-resistant bus bar cap of the present invention is not a rubber cap that will not burn in the event of a flame breaking out inside the pack, but rather has a fire-resistant silicone cap body that is ceramicized to reliably cover the bus bar and electrical connections, and can maintain its insulating and airtight properties even at high temperatures.

[0031] In addition, the fire-resistant bus bar cap of the present invention is provided with a protective layer covering the fire-resistant silicone cap body, and the protective layer serves as a primary fire-resistant wall while preventing the fire-resistant silicone cap body from being directly exposed to flames, thereby allowing the overall shape and dimensions to be maintained. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a schematic diagram showing a conventional assembly structure of a bus bar and a cap. [Diagram 2] FIG. 2 is a side cross-sectional view showing a connection relationship between a fireproof bus bar cap and a bus bar according to an embodiment of the present invention. [Diagram 3]1 is a photograph of a glass fiber layer included in a cap-integrated fire-resistant bus bar of the present invention. [Figure 4] FIG. 11 is a side cross-sectional view showing a coupling relationship between a fireproof bus bar cap and a bus bar according to another embodiment of the present invention. [Diagram 5] FIG. 11 is a side cross-sectional view showing a coupling relationship between a fireproof bus bar cap and a bus bar according to another embodiment of the present invention. [Figure 6] FIG. 11 is a side cross-sectional view showing a coupling relationship between a fireproof bus bar cap and a bus bar according to another embodiment of the present invention. [Figure 7] FIG. 11 is a side cross-sectional view showing a coupling relationship between a fireproof bus bar cap and a bus bar according to another embodiment of the present invention. [Figure 8] 8 is a schematic diagram showing a molding process of the fireproof bus bar cap of FIG. 7. FIG. [Figure 9] 8 is a schematic diagram showing a coupling relationship between the fireproof busbar cap and the busbar covering portion in FIG. 7. FIG. [Figure 10] FIG. 1 is a schematic diagram showing an example of a battery pack structure in which the cap-integrated fireproof bus bar of the present invention is installed. [Figure 11] FIG. 11 is a schematic diagram showing another example of a battery pack structure in which the cap-integrated fireproof bus bar of the present invention is installed. [Figure 12] FIG. 2 is a side cross-sectional view showing a state in which the cap-integrated fireproof bus bar of the present invention is installed in a battery pack. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] 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.

[0034] 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.

[0035] [Fireproof busbar cap] The fireproof bus bar cap of the present invention is a bus bar cap that covers a bus bar and an electrical connection part connected to the bus bar, and has an insertion space provided inside for a fastening member that fastens the bus bar and the electrical connection part, and includes a fireproof silicone cap body that is ceramicized at high temperatures, and a protective layer that covers the fireproof silicone cap body.

[0036] The busbar may include a busbar body, which is a metal conductor portion, and a covering portion that covers the busbar. The metal conductor portion may be made of a high-purity tough pitch copper material of 99.9% or more, such as C1100, or may be made of an aluminum material. Both ends of the metal conductor portion are electrically connected to corresponding electrical connection portions.

[0037] The electrical connection portion may be another bus bar fastened to one bus bar, or may be a terminal portion of a battery module fastened to the bus bar, but the corresponding electrical connection portion is not limited thereto, and may be an electrical connection portion of another portion or component that is electrically connected to the bus bar.

[0038] The fire-resistant bus bar cap of the present invention includes a fire-resistant silicone cap body that is ceramicized at high temperatures, and a protective layer that covers the fire-resistant silicone cap body.

[0039] The fire-resistant silicone is ceramicized at high temperatures. The fire-resistant silicone can be ceramicized at temperatures 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 high temperatures of 500°C or higher. Therefore, there is a limit to its application in preventing short circuits or heat propagation in battery packs under heat propagation conditions.

[0040] The fire-resistant silicone cap body has a "fire-resistant" property of being ceramicized at high temperatures of 500°C or more, so that it can maintain insulating properties and airtight properties within the battery pack even in the event of a flame.

[0041] In this manner, the fire-resistant bus bar cap according to the present invention can realize high fire resistance by including the fire-resistant silicone.

[0042] 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.

[0043] 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, which hardens at the ignition temperature and forms a condensed ceramic product when cooled. This ceramic body prevents short circuits or disconnections between conductors caused by damage to the fireproof silicone cap body even when an external mechanical impact is applied during a fire or moisture penetrates, and the busbar itself can perform its electrical function.

[0044] For this reason, the fire-resistant silicone according to the present invention comprises a silicone resin and a metal oxide.

[0045] 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"):

[0046] [Chemical formula 1]

number

[0047] In the above Chemical Formula 1, m and n are integers of 10 to 30, respectively.

[0048] 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.

[0049] In addition, the silicone compound of the formula 1 may have a weight average molecular weight adjusted to a specific range. The silicone compound of the 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 the formula 1. For example, if the weight average molecular weight of the silicone compound of the 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 bus bar cap may decrease, while there is a limit to the decrease in impact resistance. Therefore, the silicone compound of the 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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:

[0054] [Chemical formula 2]

number

[0055] In the above Chemical Formula 2, p is an integer of 10-30.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] As described above, the fire-resistant silicone according to 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 maintenance time becomes shorter, and it may not be possible to maintain the fire resistance required in the battery pack.

[0062] The fireproof silicone has rubber-like properties, such as flexibility, softness, and elasticity, before being ceramified, as described above, so that the fireproof silicone cap body can be easily injection molded as described below.

[0063] Since the fireproof silicone cap body has flexibility before being ceramicized, it can flexibly fit along the shapes of the bus bar and the electrical connection part, and therefore when the fireproof bus bar cap of the present invention is installed in a battery pack, even if there is a slight assembly tolerance, it can easily accommodate it, improving the assembly.

[0064] On the other hand, when the fireproof silicone is ceramified at high temperatures, it maintains thermal and electrical insulation, but its mechanical strength is somewhat weakened, and it may be broken by external force. In the present invention, in order to structurally improve the rigidity of the fireproof silicone cap body, a protective layer is provided to cover the fireproof silicone cap body.

[0065] The protective layer is a layer that covers the exterior of the fireproof silicone cap body and protects the fireproof silicone cap body from direct exposure to flames. That is, the protective layer primarily serves as a fireproof wall. When the fireproof silicone cap body is ceramicized, the protective layer encases the ceramicized cap body and maintains the overall shape and dimensions of the cap body. The protective layer also protects the interior of the fireproof bus bar cap from physical contact with the surroundings to prevent short circuits.

[0066] The protective layer may be made of, for example, glass fiber or mica material having both insulating and heat resistance. For example, a glass fiber tape or mica tape may be wrapped around the outside of the fireproof silicone cap body to prevent the fireproof silicone cap body 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 having excellent insulating or heat resistance.

[0067] Specific configurations of the fire-resistant bus bar cap will be described in detail in the following embodiments.

[0068] (First embodiment) FIG. 2 is a side cross-sectional view showing the connection relationship between a fireproof busbar cap and a busbar according to one embodiment of the present invention, and FIG. 3 is a photograph of a glass fiber layer included in the cap-integrated fireproof busbar of the present invention.

[0069] In this embodiment, two bus bars B1, B2 are electrically connected, and the electrical connection is covered by the fireproof bus bar cap 100. That is, in this embodiment, the electrical connection connected to the bus bar B1 is another bus bar B2. The two bus bars B1, B2 have fastening holes H1, H2 at both ends, respectively, and the two bus bars B1, B2 are electrically connected to each other by inserting and connecting fastening members F into the fastening holes H1, H2.

[0070] As shown in the figure, the fireproof busbar cap 100 includes a fireproof silicone cap body 110. The fireproof silicone cap body 110 covers at least the electrical connection portions of the busbars B1 and B2. An insertion space S for a fastening member F is provided inside the fireproof silicone cap body 110. That is, as shown in FIG. 2, when the fastening member F is fastened to the busbars B1 and B2, an exposed end of the fastening member F is inserted into the insertion space S inside the cap body 110. As a result, the fastening member F is protected by the cap body 110, and a short circuit due to contact with other external parts can be prevented. As shown in the figure, the insertion space S may have a sufficient space to accommodate the fastening member F. If necessary, a coupling member (e.g., a nut, described later) corresponding to the fastening member F may be installed in the insertion space S. Alternatively, if necessary, the size of the insertion space S may be reduced so that an end of the fastening member F is tightly fitted into the insertion space.

[0071] The fireproof silicone cap body 110 covers the upper surfaces of the electrical connection parts of the bus bars B1 and B2, but the shape of the cap body 110 can be modified to cover the side surfaces of the electrical connection parts as well, if necessary. That is, the width of the cap body 110 can be increased, the lower end of the cap body 110 can be extended downward, or a flange portion (base portion) with a large width can be provided at the lower part of the cap body 110, as described later, so that the cap body 110 covers the side surfaces of the electrical connection parts of the bus bars B1 and B2. This covers the upper surfaces and side surfaces of the bus bars B1 and B2 and their electrical connection parts, so that the insulation of the electrical connection parts can be further improved.

[0072] The fireproof silicone cap body 110 may be manufactured by a known molding method, for example, injection molding. For example, the fireproof silicone cap body 110 may be molded by injecting fireproof silicone into a mold having a shape of the fireproof silicone cap body 110. As described above, the fireproof silicone may be, for example, 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. The fireproof silicone coating liquid or slurry may be injected into a mold to mold the fireproof silicone cap body 110. After a predetermined drying and curing process, the mold is removed to obtain the fireproof silicone cap body 110 according to the present invention.

[0073] The fireproof busbar cap 100 of the present invention includes a protective layer 120 that covers the fireproof silicone cap body 110. The shape of the protective layer 120 follows the outer shape of the cap body 110 so as to cover the entire exterior of the cap body 110.

[0074] For example, a protective layer 120 such as a fiberglass tape or a mica tape can be wound onto the fireproof silicone cap body 110 to obtain the fireproof busbar cap 100 of the present invention.

[0075] For example, a material made of glass fiber or mica having both insulating and heat-resistant properties may be used as the protective layer 120. That is, a glass fiber tape or a mica tape may be wrapped around the outside of the fireproof silicone cap body 110 to prevent the fireproof silicone cap body 110 from being exposed to the outside.

[0076] In FIG. 3 a photograph of the glass fiber layer is shown.

[0077] Glass fiber is an inorganic fibrous material mainly made of silicate. Such glass fiber can be made into a glass fiber fabric by weaving a yarn made by twisting and winding glass fiber strands (see FIG. 3(a)) or into a nonwoven fabric (see FIG. 3(b)). The fire-resistant bus bar cap 100 of the present invention can be manufactured by applying a certain adhesive to such glass fiber fabric or nonwoven fabric and attaching it onto the above-mentioned fire-resistant silicone cap body 110. Glass fiber has the advantages of being fire-resistant and having high electrical insulation.

[0078] Mica is a type of silicate mineral, has a layered structure, and is usually formed in a hexagonal plate-like crystal form, and is used as an electrical insulator or heat insulating material. Mica has better fire resistance than the above-mentioned glass fiber. Therefore, mica is more preferable as the protective layer 120 that protects the fire-resistant silicone cap body 110. However, the protective layer is not limited to this, and the protective layer can be made of other materials that have excellent insulating properties or heat resistance.

[0079] For example, the protective layer 120 may be formed by winding a tape of the protective layer 120 processed into a tape shape on the fireproof silicone cap body 110. However, the method of forming the protective layer 120 is not limited thereto. For example, the protective layer 120 may be formed on the cap body by coating, painting, spraying, or other various known methods.

[0080] Second embodiment FIG. 4 is a side cross-sectional view showing a coupling relationship between a fireproof bus bar cap and a bus bar according to another embodiment of the present invention.

[0081] The fireproof busbar cap 101 of this embodiment is provided with the protective layer 120' not only on the exterior of the fireproof silicone cap body but also on the inner peripheral surface of the insertion space S for the fastening member.

[0082] That is, in the embodiment of Figure 2, there was no protective layer on the inner surface of the cap body that was not exposed to the outside, whereas in this example, the inner surface of the cap body 110 is also provided with a cap protective layer 120' such as, for example, glass fiber tape or mica tape.

[0083] In the case where both the inner and outer circumferential surfaces of the cap body 110 are covered with the cap protective layers 120, 120' as in the second embodiment, the following advantages are obtained.

[0084] The protective layers 120, 120' on the inner and outer periphery of the cap portion act as a primary fireproof barrier to ensure that the fireproof silicone of the cap body 110 is not exposed to flames.

[0085] In addition, since the cap protective layers 120, 120' on the inner and outer periphery completely enclose the fireproof silicone cap body 110 placed therebetween, even if the cap body 110 is ceramicized at high temperatures and its strength is somewhat reduced, the cap protective layers 120, 120' support the cap body, and the shape and dimensions of the cap body can be more stably maintained.

[0086] Third embodiment FIG. 5 is a side cross-sectional view showing a coupling relationship between a fireproof bus bar cap and a bus bar according to another embodiment of the present invention.

[0087] In the fireproof busbar cap 102 of this embodiment, the fireproof silicone cap body 110 includes a base portion 110A and a fastening member insertion portion 110B.

[0088] The base portion 110A may cover the side of the bus bar B1, or the side of the bus bar B1 and the corresponding electrical connection portion B2. For this purpose, the base portion 110A may have a shape like a flange portion having a width larger than that of the fastening member insertion portion 110B. The base portion 110A covers the side of the bus bar B1, or the bus bar B1 and the corresponding electrical connection portion B2, so that the insulation of the bus bar and the electrical connection portion can be more reliably achieved. The base portion 110A may extend only the base portion 110A on the exposed side surface downward so as to cover only the exposed side surface of the bus bar and the electrical connection portion. However, the shape of the base portion is not limited thereto, and other shapes of base portions are also possible as long as they can cover the side surface of the bus bar, or the side surface of the bus bar and the electrical connection portion connected thereto.

[0089] Further, the fastening member insertion portion 110B extends upward from the base portion 110A and has an insertion space S for the fastening member therein. The fastening member insertion portion 110B covers the upper surfaces of the bus bar B1 and the electrical connection portion B2.

[0090] A protective layer is provided to cover the cap body 110, following the shape of the fireproof silicone cap body 110. Therefore, the protective layer 120 also includes a base portion protective layer 120A that covers the base portion 110A, and an insertion portion protective layer 120B that covers the fastening member insertion portion 110B.

[0091] Meanwhile, as shown in FIG. 5, a separate protective layer 120' may be included on the inner circumferential surface of the fastening member insertion portion 110B.

[0092] (Fourth embodiment) FIG. 6 is a side cross-sectional view showing a coupling relationship between a fireproof bus bar cap and a bus bar according to another embodiment of the present invention.

[0093] The fireproof busbar cap 103 of this embodiment is provided with a screw groove S1 corresponding to the thread of the fastening member F along the inner peripheral surface of the fireproof silicone cap body 110 having the insertion space S for the fastening member.

[0094] In the first to third embodiments, the insertion space S for the fastening member is relatively larger than the fastening member F. Therefore, the cap body 110 can flow relative to the fastening member F.

[0095] In this embodiment, a thread groove S1 is machined on the inner peripheral surface of the cap body 110 so as to be directly coupled to the threads of the fastening member F. That is, the fastening member F can be easily coupled to the thread groove S1 by rotating the cap body 110 in the screw rotation direction. This allows the fireproof bus bar cap 103 to be reliably coupled to the fastening member F, the bus bar, and the electrical connection portion, thereby further improving the insulation strength.

[0096] Fifth embodiment FIG. 7 is a side cross-sectional view showing a coupling relationship between a fireproof busbar cap and a busbar according to another embodiment of the present invention, and FIG. 8 is a schematic view showing a molding process of the fireproof busbar cap of FIG.

[0097] In the fireproof busbar cap 104 of this embodiment, a screw coupling member N coupled to the fastening member F is coupled to the insertion space S of the fastening member. For example, the screw coupling member N such as a nut is coupled to the insertion space S of the cap body 110. Therefore, in FIG. 7, after the fastening member F is coupled to the fastening holes of the two busbars B1 and B2, when the fireproof busbar cap 104 itself is screwed to the screw coupling portion of the protruding fastening member F, the screw coupling member N inside the fireproof busbar cap 104 is screwed to the fastening member F. As a result, the fireproof busbar cap 104 not only covers the busbars B1 and B2, but also can be more firmly coupled to the busbars B1 and B2 and the fastening member F. Therefore, the insulation performance of the fireproof busbar cap 104 of this embodiment is further improved.

[0098] The fireproof busbar cap 104 of this embodiment may be manufactured by so-called insert injection molding. As shown in Fig. 8, the screw coupling member N is inserted between upper and lower molds 1 and 2 in which the outline shape 111 of the fireproof busbar cap 104 is formed, and the cap body 110 of the fireproof busbar cap 104 of this embodiment may be manufactured by insert injection molding in which the fireproof silicone is injected into the space of the outline shape 111. By such an insert injection molding method, the screw coupling member N may be easily coupled integrally with the fireproof busbar cap body 110.

[0099] After the fire-resistant silicone constituting the cap body 110 is dried and subjected to a predetermined curing process, the outside of the cap body 110 is coated with a protective layer, thereby obtaining the fire-resistant bus bar cap 104 of this embodiment.

[0100] Meanwhile, the fire-resistant busbar caps 100, 101, 102, 103, 104 according to the present invention may be attached to the coating layer 12 of the busbar B1. As shown in Fig. 9, the end of the coating layer 12 may be connected to the lower end (base portion) of the fire-resistant busbar cap with, for example, a wear-resistant tape 30, thereby connecting the busbar and the fire-resistant busbar cap.

[0101] [Battery pack] FIG. 10 is a schematic diagram showing an example of a battery pack structure in which the cap-integrated fire-resistant busbar of the present invention is installed, FIG. 11 is a schematic diagram showing another example of a battery pack structure in which the cap-integrated fire-resistant busbar of the present invention is installed, and FIG. 12 is a side cross-sectional view showing the state in which the cap-integrated fire-resistant busbar of the present invention is installed in a battery pack.

[0102] The above-mentioned fireproof busbar caps 100, 101, 102, 103, and 104 of the present invention include a fireproof silicone cap body 110 that is ceramicized at high temperature, and a protective layer 120 that wraps the fireproof silicone cap body 110 to maintain its shape. Therefore, when applied to a battery pack in which internal fire may occur, the safety of the battery pack can be significantly improved.

[0103] In particular, the high voltage terminals of the battery modules generate relatively high heat due to high currents, and thus, when a fire occurs inside the pack, high heat may be concentrated on the high voltage terminals. Therefore, the fire-resistant bus bar caps 100, 101, 102, 103, and 104 of the present invention are suitable for use as insulating caps for covering electrical connections of the high voltage terminals of multiple battery modules.

[0104] 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, bus bars B1, B2 electrically connecting the battery modules, the fireproof bus bar caps 100, 101, 102, 103, 104 covering the electrical connection portions of the battery modules and the bus bars, and a pack housing 400 accommodating the battery modules and the fire prevention partitions.

[0105] 10, 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. A cap-integrated fireproof bus bar according to the present invention may be applied to electrically connect the plurality of battery modules.

[0106] Meanwhile, Figs. 10 and 11 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 fireproof busbar cap 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 fireproof busbar caps 100, 101, 102, 103, and 104 of the present invention may be used for electrical connection of a cell block or a moduleless battery module installed in such a cell-to-pack battery pack.

[0107] 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. 10 shows that the fire prevention partition 300 is provided with a busbar installation through hole 310, and FIG. 11 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 in FIG. 10 is advantageous. The busbar installation groove 320 in FIG. 11 has an open upper portion, which is advantageous for performing busbar installation and electrical connection work of the busbar.

[0108] The bus bar B1 may be seated in the bus bar installation through hole 310 or the bus bar installation groove 320. At this time, both ends of the bus bar may be electrically coupled to terminal parts 210 and 220 of the battery modules 200 located on both sides of the fire prevention partition 300.

[0109] 10 and 11 show how the busbar electrically connects the battery modules 200 in the battery pack 1000. A fireproof partition 300 is disposed between adjacent battery modules 200, and the fireproof partition has a busbar installation through hole 310. The busbar is seated on the busbar installation through hole 310. The fireproof busbar caps 100, 101, 102, 103, and 104 cover both ends of the busbar and the connection portions of the terminal parts 210 and 220.

[0110] Meanwhile, in the case where a fire occurs in the battery pack 1000, the fireproof busbar caps 100, 101, 102, 103, and 104 of the present invention form a dense sintered body by ceramicizing the cap body 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 busbar caps 100, 101, 102, 103, and 104 are ceramicized and maintain their shape. As a result, the fireproof busbar caps 100, 101, 102, 103, and 104 can stably cover the joints and maintain insulation of the joints. The protective layer 120 prevents the fireproof silicone cap body 110 from coming into direct contact with the flame, preventing deformation of the fireproof silicone, and further enhancing insulation and fire resistance.

[0111] [Experimental Example]

[0112] (Experimental Example 1) A 105×105×1 mm sized fireproof silicone test piece was prepared by mixing 50 parts by weight of the silicone compound of Formula 1, 20 parts by weight of quartz, and 30 parts by weight of pure silicon dioxide, and a 0.18 mm thick glass fiber tape (product name: AGT6WO) manufactured by SWECO was attached to the test piece to prepare Example 1.

[0113] A 0.18 mm thick mica tape (product name: SA765) manufactured by SWECO was attached to the fireproof silicone specimen to prepare a specimen of Example 2.

[0114] Test pieces for Comparative Examples 1 and 2 having the same size and thickness as those for Examples 1 and 2 were manufactured by alternately laminating a plurality of sheets of AGT6WO glass fiber tape and SA765 mica tape.

[0115] The specimens of Examples 1 and 2 and Comparative Example 1 were uniformly heated over the entire surface for 3 minutes with a large torch having a flame temperature of 1100 to 1150°C, and the temperature of the back surface of the specimen was measured. The measurement results are shown in Table 1 below.

[0116] [Table 1] Experimental example 1 Specimen configuration Specimen backside temperature Comparative Example 1: 2 mica tapes + 4 glass fiber tapes 560℃ Comparative Example 2: 4 mica tapes + 2 glass fiber tapes 440℃ Example 1 Fireproof silicone + fiberglass tape 405℃ Example 2 Fireproof silicone + mica tape 350℃

[0117] As shown in Table 1 above, Examples 1 and 2 having the fire-resistant silicone specimen and protective layer applied to the fire-resistant busbar cap of the present invention had a lower temperature rise rate on the back side of the specimen than Comparative Examples 1 and 2.

[0118] Therefore, it can be seen that the insulating and heat insulating properties of the fireproof busbar cap of the present invention, which is equipped with the above-mentioned fireproof silicone cap body and protective layer, are very excellent. In particular, compared to the example using the glass fiber tape as the protective layer like Example 2, Example 2 using the mica tape as the protective layer had better insulating performance.

[0119] (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 silicone specimens having the compositions shown in Table 2 below.

[0120] A mica tape (product name: SA765) of 0.18 mm thickness manufactured by SWECO was attached to a fireproof silicone specimen having the composition of Table 2 to prepare specimens of Examples 1-1 to 1-5.

[0121] The entire surfaces of the specimens of Examples 1-1 to 1-5 were uniformly heated for 3 minutes with a large torch having a flame temperature of 1100 to 1150° C., and the temperature of the back surface of the specimen was measured. The measurement results are shown in Table 2 below.

[0122] [Table 2] Experimental Example 2 Composition of fireproof silicone Temperature on the back side of the specimen Example 1-1 Silicone compound 50 parts by weight: Metal oxide 50 parts by weight (Quartz: 20 parts by weight, pure silicon dioxide: 30 parts by weight) 350℃ Example 1-2 Silicone compound 50 parts by weight: Metal oxide 25 parts by weight (Quartz: 10 parts by weight, pure silicon dioxide: 15 parts by weight) 380℃ Example 1-3 50 parts by weight of silicone compound: 75 parts by weight of metal oxide (Quartz: 30 parts by weight, pure silicon dioxide: 45 parts by weight) 330℃ Examples 1-4 Silicone compound 50 parts by weight: Metal oxide 20 parts by weight (Quartz: 10 parts by weight, pure silicon dioxide: 10 parts by weight) 390℃ Examples 1-5 Silicone compound 50 parts by weight: Metal oxide 80 parts by weight (Quartz: 35 parts by weight, pure silicon dioxide: 45 parts by weight) 321℃

[0123] In the above Examples 1-1 to 1-5, 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.

[0124] In all examples, the temperature of the backside of the specimen was lower than in Comparative Examples 1 and 2. However, in the case of Examples 1-4, in which the weight ratio was less than 0.5, the temperature of the backside of the specimen was somewhat higher. This is believed to be due to the fact that the metal oxide was insufficient, resulting in the formation of a ceramic structure having a high density crystal structure at high temperatures.

[0125] In addition, in the case of Example 1-5 where the weight ratio is 1.6, the temperature of the back surface of the test piece was sufficiently low, but the amount of metal oxide was excessive, so the flexibility of the fireproof silicone at room temperature was reduced, and the moldability of the fireproof bus bar cap was poor.

[0126] 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]

[0127] 100, 101, 102, 103, 104: Fireproof busbar caps 110: Fireproof silicone cap body 110A: Base section 110B: Fastening member insertion part 120, 120': Protective layer 120A: Base protection layer 120B: Insertion part protection layer S: Insertion space for fastening members H1, H2: Fastening holes B1, B2: Busbar S1: Thread groove N: Screw connection material 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 cap for covering a bus bar and an electrical connection coupled to the bus bar, a fire-resistant silicone cap body that is provided with an insertion space for a fastening member for fastening the bus bar and the electrical connection portion thereto, and that is turned into a ceramic at a high temperature; a protective layer covering the fire-resistant silicone cap body; Includes fire resistant busbar caps.

2. 2. The fire resistant bus bar cap of claim 1, wherein the fire resistant silicone cap body is ceramified at a temperature of 500-1700°C.

3. 2. The fireproof busbar cap according to claim 1, wherein the fireproof silicone cap body is ceramicized by sintering a silicone resin including a silicone compound represented by the following chemical formula 1 and a metal oxide including silicon oxide: [Chemical formula 1] [0010] In the above formula 1, m and n are each an integer of 10 to 30.

4. The fireproof bus bar cap 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 bus bar cap 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 cap of claim 1 , wherein the protective layer is a fiberglass layer or a mica layer.

7. The fireproof busbar cap according to claim 1 , wherein the protective layer is provided on an inner peripheral surface of an insertion space of the fireproof silicone cap body for inserting a fastening member.

8. The fire-resistant silicone cap body is a base portion covering a side surface of the bus bar or a side surface of the bus bar and an electrical connection portion; a fastening member inserting portion extending upward from the base portion, the fastening member inserting portion having an insertion space therein for the fastening member, and covering upper surfaces of the bus bar and the electrical connection portion; 2. The fire resistant bus bar cap of claim 1 , comprising:

9. The fireproof busbar cap according to claim 1 , wherein a screw groove corresponding to the screw thread of the fastening member is provided along an inner peripheral surface of a fireproof silicone cap body having an insertion space for the fastening member.

10. The fire-resistant bus bar cap according to claim 1 , wherein a screw-type fastening member is connected to the fastening member in an insertion space of the fastening member.

11. 11. The fire resistant bus bar cap of claim 10, wherein the threaded coupling member is integrally coupled to the fire resistant bus bar cap by insert injection molding, in which the threaded coupling member is inserted into a mold and fire resistant silicone is injection molded.

12. A plurality of battery modules; a fire prevention partition installed between the battery modules; A bus bar electrically connecting the battery modules; A fireproof busbar cap according to any one of claims 1 to 11, which covers an electrical connection between the battery module and the busbar; a pack housing that houses the battery module and a flame-prevention partition.

13. The fire prevention partition has a bus bar installation through hole or a bus bar installation groove, The busbar is seated in the busbar installation through-hole or the busbar installation groove, both ends of the bus bar are electrically connected to terminal portions of the battery modules located on both sides of the fire prevention partition; 13. The battery pack of claim 12, wherein the fire resistant bus bar caps cover the electrical connections at the ends and terminals.

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