KR20240056202A - Fireproof busbar and battery pack hanving the same - Google Patents

Abstract

The fire-resistant bus bar of the present invention includes a bus bar conductor portion; A fire-resistant silicon coating layer that surrounds the bus bar conductor portion except for both ends and is ceramicized at a high temperature to support the bus bar conductor portion; and a metal case in which the bus bar conductor portion and the fire-resistant silicone coating layer are accommodated, and having openings on both sides through which both ends of the bus bar conductor portion are exposed to the outside.
Additionally, the present invention provides a battery pack including the fire-resistant bus bar.

Description

Fireproof busbar and battery pack including the same {FIREPROOF BUSBAR AND BATTERY PACK HANVING THE SAME}

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

More specifically, it relates to a fire-resistant bus bar and battery pack that has a fire-resistant silicon coating layer that becomes ceramic at high temperature and a metal case surrounding this coating layer, and can maintain insulating and airtight properties even at high temperatures where ignition occurs inside the battery pack. will be.

Battery packs applied to electric vehicles, etc. have a structure in which multiple battery modules including a plurality of secondary batteries are connected in series or parallel to obtain high output. In addition, the secondary battery is capable of repeated charging and discharging through electrochemical reactions between components, including positive and negative electrode current collectors, separators, active materials, and electrolyte solutions.

To electrically connect the battery modules, a bus bar is used. The bus bar is used to electrically connect terminal portions of adjacent battery modules or to connect battery modules to external electrical devices.

1 is a schematic and cross-sectional view showing a conventional bus bar structure.

As shown, the conventional bus bar 10 consists of a bus bar conductor portion 11 and a covering layer 12 surrounding the bus bar 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 common silicone rubber or epoxy. In Figure 1, the bus bar 10 is shown to electrically connect the battery module 20 installed in the battery pack. The bus bar 10 is installed in the through hole 31 of the partition wall 30 installed between the battery modules 20, and both ends of the exposed metal conductor part of the bus bar 10 are connected to the module terminal parts on both sides of the partition wall. are connected to each.

When, for example, battery modules are electrically connected to the conventional bus bar within a battery pack, no problem occurs in the operation of the battery pack at normal temperatures at which the battery pack operates normally.

However, when a flame occurs inside the battery pack, the temperature of the flame is very high (500 to 800℃, or over 800℃, and in severe cases, over 1000℃), so the silicone rubber or epoxy coating layer melts and the bus bar conductor part is exposed to the outside. It is exposed as. In this case, the exposed bus bar conductor part electrically contacts other metal parts in the pack, causing a short circuit, and the flame spreads further due to heat generation from the electric short circuit.

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

However, in extreme heat generation situations as described above, the materials exemplified above cannot sufficiently prevent heat diffusion. For example, typical heat-resistant silicone rubber has a heat-resistant temperature of only 125 to 300 degrees Celsius, so it cannot effectively deal with ignition situations inside the battery pack. Additionally, mica sheets and glass fiber coating layers do not have sufficient fire resistance.

As such, in recent battery packs, it is essential to design them so that flames do not leak out of the pack when ignited.

In addition, a design that can thermally and electrically insulate the bus bar conductor from the surroundings is needed even at high temperatures when a flame occurs inside the battery pack.

Meanwhile, when a bus bar connects battery modules, there are cases where the bus bar is supported by or installed through a structure (eg, a partition wall) of the battery pack. In this case, the covering layer of the busbar may be damaged by the sharp edge of the partition, which may damage the insulation of the busbar conductor portion or damage its airtightness.

From the above, there is a need for the development of technology that can improve insulation strength and assembly properties while maintaining electrical insulation properties by providing fire resistance at high temperatures.

Korean Patent Publication No. 2022-0001228

The purpose of the present invention is to provide a fire-resistant bus bar that can maintain thermal and electrical insulation for as long as possible even when a flame occurs inside a battery pack.

Additionally, the present invention is to provide a battery pack equipped with the fire-resistant bus bar.

The fire-resistant bus bar of the present invention for solving the above problems includes a bus bar conductor portion; A fire-resistant silicon coating layer that surrounds the bus bar conductor portion except for both ends and is ceramicized at a high temperature to support the bus bar conductor portion; and a metal case in which the bus bar conductor portion and the fire-resistant silicone coating layer are accommodated, and having openings on both sides through which both ends of the bus bar conductor portion are exposed to the outside.

The refractory silicon can be ceramicized at a temperature of 500 to 1700°C.

The fire-resistant silicone includes a silicone resin containing a silicone compound represented by the following formula (1); It can be ceramicized by sintering a metal oxide containing silicon oxide.

[Formula 1]

In Formula 1, m and n are each integers of 10 to 30.

The silicone resin and metal oxide may be included in a weight ratio of 1:0.5 to 1.5.

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

The metal case includes an upper case and a lower case, and the upper and lower cases can be coupled by hook coupling.

An insulating layer made of a material different from the fire-resistant silicon coating layer may be provided between the bus bar conductor portion and the fire-resistant silicon coating layer.

At least one of the inner and outer surfaces of the metal case may be anodized.

The metal case may be made of aluminum, steel, or stainless steel.

The fire-resistant bus bar may be a high-voltage bus bar that electrically connects high-voltage terminals of a plurality of battery modules.

A battery pack as another aspect of the present invention includes a plurality of battery modules; A flame prevention partition installed between the battery modules; The above-described fire-resistant bus bar electrically connecting the battery module; And it may include a pack housing accommodating the battery module and the flame prevention partition.

The flame prevention partition is provided with a bus bar installation through hole or a bus bar installation groove, and the metal case of the fireproof bus bar is seated in the bus bar installation through hole or the bus bar installation groove, and is led out from the opening of the metal case. Both ends of the bus bar may be electrically coupled to terminal parts of the battery module located on both sides of the flame prevention partition.

The metal case may be formed to correspond to the shape of the bus bar installation through hole or bus bar installation groove.

The fire-resistant bus bar of the present invention has a fire-resistant silicon coating layer that is ceramicized and supports the bus bar conductor portion instead of a coating layer that burns away when a flame occurs inside the pack, so it can maintain insulating and airtight properties even at high temperatures.

In addition, the fireproof bus bar of the present invention is provided with a metal case surrounding the fireproof silicon coating layer. The metal case maintains the shape of the busbar conductor portion and wraps the refractory silicon to prevent the refractory silicon from being directly exposed to flame, thereby preventing deformation of the refractory silicon and further strengthening the insulation and airtight properties.

In addition, the metal case protects the fire-resistant silicon and bus bar conductor, preventing insulation damage due to sharp edges, and improving airtightness with the battery pack partition.

1 is a schematic and cross-sectional view showing a conventional bus bar structure.
Figure 2 is a perspective view of a fire-resistant bus bar according to an embodiment of the present invention.
Figure 3 is a perspective view of the bus bar conductor included in the fire-resistant bus bar of the present invention.
Figure 4 is a perspective view showing a state before assembly of the metal case of the fire-resistant bus bar of Figure 2.
Figure 5 is a cross-sectional view of the fire-resistant bus bar of the embodiment of Figure 2.
Figure 6 is a cross-sectional view of a fire-resistant bus bar of another embodiment of the present invention.
Figure 7 is a perspective view of a bus bar conductor provided in the fire-resistant bus bar of Figure 6.
Figure 8 is a schematic diagram showing an example of a battery pack structure in which the fire-resistant bus bar of the present invention is installed.
Figure 9 is a schematic diagram showing another example of a battery pack structure in which the fire-resistant bus bar of the present invention is installed.
Figure 10 is a perspective view showing the fire-resistant bus bar of the present invention installed in a battery pack.
Figure 11 is a side cross-sectional view showing the fire-resistant bus bar of the present invention installed in a battery pack.

Hereinafter, the detailed configuration of the present invention will be described in detail with reference to the attached drawings and various embodiments. The embodiments described below are shown as examples to aid understanding of the present invention, and the attached drawings are not drawn to scale to aid understanding of the invention, and the dimensions of some components may be exaggerated. .

Since the present invention can be subject to various changes and have various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

[Fireproof bus bar]

The fire-resistant bus bar of the present invention includes a bus bar conductor portion; A fire-resistant silicon coating layer that surrounds the bus bar conductor portion except for both ends and is ceramicized at a high temperature to support the bus bar conductor portion; and a metal case in which the bus bar conductor portion and the fire-resistant silicone coating layer are accommodated, and having openings on both sides through which both ends of the bus bar conductor portion are exposed to the outside.

The bus bar conductor part may be a normal metal conductor part. In other words, it can be made of 99.9% or higher purity tough pitch copper material such as C1100, or it can also be made of aluminum material. That is, the busbar conductor portion of the present invention is not particularly limited as long as it is made of a metal material that can function as a busbar conductor for connecting electrical components. Both ends of the bus bar conductor portion are electrically connected to corresponding electrical connection portions.

The fire-resistant silicone coating layer is a layer that covers the bus bar conductor portion while surrounding the portion excluding both ends of the bus bar conductor portion. That is, the fireproof silicon coating layer is covered around the central portion of the bus bar conductor portion excluding both ends. The refractory silicon coating layer is ceramicized at a high temperature to support the bus bar conductor portion. The refractory silicon can be ceramicized at a temperature of 500 to 1700°C. The fire-resistant silicon of the present invention is distinguished from heat-resistant silicon with a heat-resistant temperature of less than 300° C. in that it has a fire-resistant temperature of 500° C. or higher. Heat-resistant silicone is a silicone resin or rubber composition that has flexibility and flexibility due to the characteristics of silicone, but it is a material that does not become ceramic and burns out or turns into ash at high temperatures above 500°C. Therefore, there is a limit to its application in preventing short-circuiting or heat propagation of a battery pack in a heat propagation situation.

Since the fire-resistant silicone coating layer has 'fire-resistant' properties that make it ceramic at a high temperature of 500°C or higher, it can maintain insulating and airtight properties within the battery pack even when a flame occurs.

In this way, the fire-resistant bus bar according to the present invention can realize high fire-resistant performance by providing fire-resistant silicon inside along with structural improvement.

The fireproof silicone is a composition containing silicone resin and metal oxide as main ingredients, and has flexibility and flexibility due to the characteristics of silicone at room temperature. In addition, it has a certain elasticity and exhibits high impact resistance and insulation, and when exposed to high temperatures, a silicon sintered body with a complex ceramic structure can be formed by sintering silicon resin and metal oxide.

Specifically, the silicone resin contained in fireproof silicon generates silica in powder form when burned at high temperature. The silica produced in this way reacts with the metal oxide of the refractory silicon to form a "eutectic mixture" on the edge of the metal oxide, thereby performing a bridging role between the silica and the metal oxide, so it hardens at the ignition temperature. , when cooled, forms a condensed ceramic product. This ceramic body can exercise the electrical function of the bus bar itself by preventing short circuits or disconnections between conductors due to damage to the fire-resistant silicon coating layer even when external mechanical shock is applied or moisture penetrates in the event of a fire.

For this purpose, the refractory silicone according to the present invention contains a silicone resin and a metal oxide.

The silicone resin is not particularly limited as long as it contains silicon (Si) in the molecule, but preferably may include a silicone compound represented by the following formula (1) (hereinafter referred to as “the silicone compound of formula 1”):

[Formula 1]

In Formula 1, m and n are each integers of 10 to 30.

The silicone compound of Formula 1 includes a methylsiloxane repeating unit, and includes vinyl groups inside and at the ends of the methylsiloxane repeating unit, respectively. The vinyl group is present not only at the ends 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. Through this, it can realize better fire resistance properties compared to silicone compounds that do not contain a vinyl group. You can.

Additionally, the weight average molecular weight of the silicone compound of Formula 1 may be adjusted to a specific range. The silicone compound of Formula 1 is a compound that forms the base of a silicone resin, and depending on the weight average molecular weight of the silicone compound of Formula 1, it can affect the physical properties of fireproof silicon at room temperature and high temperatures. For example, if the weight average molecular weight of the silicone compound of Formula 1 is excessively high, the viscosity of the silicone resin may increase and reactivity may decrease during high temperature sintering, and if the weight average molecular weight is significantly low, the room temperature elasticity and flexibility of the silicone resin may decrease. As a result, the manufacturing process of the fire-resistant bus bar is degraded, and there is a limit to the impact resistance, etc. Therefore, the silicone compound of 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; Alternatively, it may have an adjusted value of 5,000 to 7,000 g/mol.

In addition, the metal oxide is a composition containing silicon oxide, and can act as a crystal nucleus when exposed to high temperature to form a high-density ceramic body together with the above-described silicone resin.

These metal oxides may include one or more of silicon dioxide, silica, quartz, silica, tridymite, and keatite. The metal oxide contains pure silicon dioxide (SiO ₂ ) as well as minerals such as quartz containing silicon dioxide (SiO ₂ ) as a main component, so it is not only highly economical, but also has a high melting point (high refractoriness) and 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 dissolution and molding of refractory silicon, and reduce defects that may occur in ceramic bodies.

In addition, it is good if the metal oxide can be sintered with a silicone resin to have a crystal structure that increases fire resistance, insulation, and mechanical strength. This metal oxide is in the form of a powder, but is not particularly limited, and has a size of 200 μm or less, for example, 0.1 μm to 200 μm; Alternatively, those having a size of 0.1㎛ ~ 100㎛ can be used.

In addition, the silicone resin may further include a silicon compound represented by the following Chemical Formula 2 (hereinafter referred to as “the silicone compound of Chemical Formula 2”), and the silicone compound of Chemical Formula 2, together with the silicon compound of Chemical Formula 1, acts as a metal at high temperature. Participates in sintering of the oxide to form a silicon sintered body:

[Formula 2]

In Formula 2, p is an integer of 10 to 30.

The silicone compound of Formula 2 increases the flexibility of the refractory silicon at room temperature, and can play a role in inducing the completion of sintering of the silicone resin through dehydration condensation with the silicone compound of Formula 1 during sintering, through which The ceramic body formation reaction can be terminated.

For this purpose, 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, based on the total weight of the fireproof silicon; 1 to 6 parts by weight; Alternatively, it may be used in an amount of 2 to 5 parts by weight.

In addition, fireproof silicon may contain silicone resin and metal oxide in a certain ratio in order to realize high elasticity at room temperature and to quickly form a ceramic body when exposed to high temperatures.

Specifically, the refractory silicon may have a weight ratio of silicone resin and metal oxide of 1:0.5 to 1.5, and specifically, 1:0.8 to 1.2. If the weight ratio of the metal oxide is low (less than 0.5), it is difficult to have a ceramic structure with a high density crystal structure at high temperature, so there is a problem of insufficient fire resistance and mechanical strength. Additionally, if the weight ratio of the metal oxide exceeds 1.5, the flexibility of the refractory silicon is reduced at room temperature, resulting in poor handleability.

As an example, the fire-resistant silicone of the present invention contains 35 to 50% by weight of the silicone compound of Formula 1; Quartz 16-32% by weight; 10-27% by weight of silicon dioxide; and a second silicone compound of Formula 2 in an amount of 1 to 6% by weight, and in some cases, a predetermined solvent may be additionally included to increase fairness during manufacturing.

As described above, the refractory silicon of the present invention is hardened by sintering a silicone resin and a metal oxide at 500° C. or higher to become ceramic. In addition, it is ceramicized up to 1700℃, and theoretically, it can partially maintain ceramicization even at temperatures above 1700℃. However, if the temperature exceeds 1700°C, the ceramicization retention time becomes shorter and the fire resistance required for the battery pack may not be maintained.

Before being ceramicized, the refractory silicone has rubber-like properties such as flexibility, flexibility, and elasticity, as described above. Therefore, it is easy to inject the fireproof silicone coating layer into a metal case, which will be described later, and injection mold it or apply it inside the metal case. Additionally, when the bus bar conductor portion is inserted into the fire-resistant silicon coating layer provided in the metal case, the flexible fire-resistant silicon surrounds the bus bar conductor portion while pressing the bus bar conductor portion. Accordingly, the flexible fire-resistant silicon can cover the bus bar conductor portion tightly while following the shape of the bus bar conductor portion.

Since the fireproof silicon coating layer has flexibility before being ceramicized, it can flexibly follow the deformation of the bus bar conductor portion. Therefore, when installing the fire-resistant bus bar of the present invention in a battery pack, even if there is a slight assembly tolerance, it can be easily accommodated, thereby improving assembly efficiency. For example, when attaching a battery module to a battery pack by bolting, if the bus bar conductor portion connected to the battery module moves or is slightly distorted, the fireproof silicon coating layer can absorb such movement or distortion. Additionally, even when the battery pack vibrates due to the vibration of the electric vehicle, the fireproof silicon coating layer can naturally absorb the vibration.

Meanwhile, ceramicized refractory silicon directly surrounds and supports the bus bar conductor portion and can maintain the shape of the bus bar conductor portion.

The fire-resistant bus bar of the present invention also includes a metal case in which the bus bar conductor portion and the fire-resistant silicone coating layer are accommodated.

The metal case may include openings on both sides through which both ends of the bus bar conductor are exposed to the outside. Both ends of the bus bar conductor portion may be exposed to the outside through the openings on both sides. Additionally, both ends of the bus bar conductor portion may be coupled to corresponding electrical connection portions.

The metal case maintains the shape of the bus bar conductor portion. In addition, the fire-resistant silicon coating layer is wrapped to prevent the fire-resistant silicon coating layer from being directly exposed to flame when the inside of the battery pack ignites. Accordingly, the fireproof silicone coating layer can be prevented from being deformed and the insulating and airtight properties can be strengthened. In addition, the metal case holds the outer shape of the fireproof silicon tightly so that it does not collapse when the battery pack ignites internally, making it possible to maintain insulation and airtightness for a long time.

Additionally, when the metal case is installed, for example, in a battery pack, it can maintain airtightness by adhering to the assembly space within the battery pack. Since the metal case has a hard surface, even if there are sharp edges in the assembly space within the battery pack, it can prevent damage to the insulation in the fireproof busbar or the busbar conductor portion.

The metal case may be made of aluminum, steel, or stainless steel. However, it is not limited to this, and the metal case can be manufactured from other metal materials as long as it has the strength to protect the busbar conductor portion and the fireproof silicon coating layer and is easy to form or process.

Surface treatment may be performed on the surface of the metal case to reinforce insulation. For example, anodizing may be performed on the inner or outer surface or both the inner and outer surfaces of the metal case.

Anodizing is one of the metal surface treatment technologies belonging to chemical conversion coating treatment along with phosphate coating treatment and chromate treatment, and is a technology applied to improve corrosion resistance and wear resistance of non-ferrous metal products such as aluminum, titanium, copper, and magnesium. When the target metal is placed on an anode and electrolyzed in a diluted acid solution, an oxide film is formed by oxygen generated from the anode. In the case of aluminum, alumina (Al ₂ O ₃ ) is formed as an oxide film. Since this oxide film is an insulator, a metal case made of anodized metal (e.g., aluminum) becomes a surface insulator. Accordingly, the fire-resistant bus bar of the present invention equipped with an anodized metal case is provided with two electrical insulators. That is, a fireproof silicon coating layer is provided as a first insulator, and an oxide film on the surface of the metal case is provided as a second insulator. Therefore, the insulation of the fire-resistant bus bar is further improved by anodizing treatment.

If the metal case is in a form that accommodates the bus bar conductor part and the fire-resistant silicone coating layer surrounding the bus bar conductor part, it may be in the form of a case formed as an integrated body or in the form of a case in which separate case parts are combined with each other to form a single case. possible. However, whatever the shape, it is necessary to have openings on both sides through which both ends of the bus bar conductor can be brought out to the outside.

The specific forms of the fire-resistant bus bar and metal case will be described in detail in the following embodiments.

(First Embodiment)

Figure 2 is a perspective view of a fire-resistant bus bar according to an embodiment of the present invention, Figure 3 is a perspective view of the bus bar conductor part included in the fire-resistant bus bar of the present invention, and Figure 4 is an assembly of the metal case of the fire-resistant bus bar of Figure 2. It is a perspective view showing the entire state, and Figure 5 is a cross-sectional view of the fire-resistant bus bar of the embodiment of Figure 2.

Referring to the drawings, the metal case 130 according to the fire-resistant bus bar 100 of this embodiment includes an upper case 130A and a lower case 130B. That is, in this embodiment, the metal case 130 is not formed as one piece, but is composed of two parts. The upper case 130A and the lower case 130B can be easily coupled by providing a hook coupling portion 132. That is, the lower case 130B has a protrusion 132B on the upper front side, and the upper case 130A has a hook portion 132A into which the protrusion is inserted on the lower front side. The hook portion 132A and the protrusion 132B constitute the hook coupling portion 132. As shown in FIG. 4, the side surfaces of the upper case 130A and the lower case 130B on which the hook coupling portion 132 is not formed are connected to each other by a hinge coupling. Accordingly, one of the upper and lower cases can be moved (rotated) relative to the other by rotating the hinge. In the state of FIG. 4, one of the upper and lower cases is rotated relative to the other to approach each other, and the protruding portion 132B is inserted into the hook portion 132A to couple the upper and lower cases to form the metal case 130 of the present invention. is achieved.

As shown in FIG. 4, opening grooves 131A and 131B are provided on both sides of the upper case 130A and the lower case 130A, respectively. Accordingly, when the upper and lower cases are combined, the opening groove 131A of the upper case and the opening groove 131B of the lower case are engaged with each other to form the opening 131. Both ends of the bus bar conductor portion 110 may be exposed to the outside through the opening 131. The size or shape of the opening grooves 131A and 131B provided in the upper and lower cases do not necessarily need to be the same. If the two open grooves 131A and 131B can be engaged to form an opening that matches the shape of the bus bar conductor portion, for example, one of the two open grooves may be smaller than the other.

In this embodiment, the two open grooves 131A and 131B are engaged to form the opening 131, but the present invention is not limited thereto. For example, openings may be formed on both sides of one of the upper case 130A or lower case 130B, and the other case may be closed without openings. However, as in the present embodiment, when the two cases each have an opening groove and the two open grooves are combined to form an opening, the bus bar conductor portion 110 is placed between the upper and lower cases, and the upper and lower cases are combined to form an opening. There is an aspect that makes it convenient to assemble the fireproof bus bar.

In addition, the bus bar conductor portion 110 can be more easily fixed to the metal case 130 by hook coupling.

Figure 3 shows the bus bar conductor portion 110. The bus bar conductor portion 110 is a metal conductor portion and is provided with a fastening hole 111A for fastening with an electrical connection portion (eg, a terminal portion of a battery module) corresponding to both ends 111.

Referring to FIG. 4, the inside of the upper case 130A is filled with the upper fire-resistant silicon coating layer 120A, and the inside of the lower case 130B is filled with the lower fire-resistant silicon coating layer 120B. The assembly process of the bus bar conductor portion 110 and the metal case 130 will be described with reference to FIGS. 2 and 4. The bus bar conductor portion 110 is positioned on one of the upper and lower refractory silicon coating layers 120A and 120B, for example, the lower refractory silicon coating layer 120B. At this time, the lower portions of both ends of the bus bar conductor portion 110 are positioned on the open grooves 131B provided on both sides of the lower case 130B, and the both ends are extended out of the open grooves 131B by a certain length. do. Next, the upper case 130A is hooked to the lower case 130B while the open groove 131A of the upper case 130A covers the upper portions of both ends of the bus bar conductor portion 110. When the upper and lower cases are hooked together as shown in Figures 2 and 5, the bus bar conductor portion 110 is pressed by the fireproof silicon coating layers 120A and 120B of the upper and lower parts by the hook coupling force and is fixed within the metal case 130. It will happen. Since the refractory silicon coating layer 120 has elasticity and flexibility, the bus bar conductor portion 110 is pressed and buried in the upper and lower refractory silicon by the hook bonding force. Accordingly, the bus bar conductor portion 110 is covered with the fireproof silicon coating layer 120 and fixed within the metal case 130 in the form shown in FIG. 5. At this time, both ends of the bus bar conductor portion 110 are extended to the outside by a certain length. The outer circumference of the bus bar conductor portion 110 is regulated by the inner peripheral surface of the opening groove 131A of the upper case 130A and the inner peripheral surface of the lower case opening groove 131B, so that the bus bar conductor portion 110 is stably enclosed in the metal case ( 130). Since the fireproof silicone coating layer 120 has flexibility and flexibility, when the upper and lower cases are combined, the combined pressure may partially push out through the opening 131 made of the open grooves 131A and 131B. (See Figure 2).

In this way, by configuring the metal case 130 into an upper and lower case and combining the upper and lower cases by hook coupling, the bus bar conductor portion 110 is fixed (covered) to the fireproof silicone coating layer 120 and the metal case 130. ) can be assembled simultaneously.

If necessary, a shape (not shown) corresponding to the outer circumferential shape of the bus bar conductor portion 110 may be formed in the upper fire-resistant silicon coating layer 120A and the lower fire-resistant silicon coating layer 120B shown in FIG. 4. . For example, if the elasticity and flexibility of the fireproof silicone coating layer 120 are not sufficient, the busbar conductor portion may not be completely surrounded by the fireproof silicone coating layer 120 despite the hook bonding force of the upper and lower cases. In this case, a space may be partially formed between the bus bar conductor portion 110 and the fireproof silicon coating layer 120. In order to prevent the above-mentioned space from being created, for example, shapes corresponding to the upper half outer circumference shape and the lower half outer circumference shape of the bus bar conductor portion 110 are provided on the upper fireproof silicon coated layer 120A and the lower fireproof silicon coated layer 120B. The shape of the upper and lower fireproof silicone coating layers can be molded. However, the fireproof silicon having the composition of the above-described embodiment has sufficient elasticity and flexibility, so in principle, even if the shape of the busbar conductor is not formed, it can be flexibly deformed by the hook bonding force to tightly wrap the busbar conductor.

Assembly of the bus bar conductor portion 110 and the metal case 130 can be performed in advance as shown in FIGS. 4 and 5. Alternatively, the fire-resistant silicone coating layer 120 may be previously charged or applied to the metal case 130, and then the bus bar conductor portion 110 may be joined to the metal case 130 only at the site where the battery pack is installed.

In addition, when forming the fireproof silicon coating layer 120 within the metal case 130, flexible fireproof silicon is applied to the metal case 130, or an opening is formed in a part of the metal case 130 and the fireproof silicon flows through the opening. It is also possible to charge silicon from outside. In the latter case, for example, by placing the bus bar conductor portion 110 in advance within the metal case 130 and injecting (injection molding) fire-resistant silicon into the metal case 130 through the opening, the fire-resistant silicon is naturally It is also possible to surround and cover the bus bar conductor portion 110.

(Second Embodiment)

Figure 6 is a cross-sectional view of a fire-resistant bus bar of another embodiment of the present invention, and Figure 7 is a perspective view of the bus bar conductor portion provided in the fire-resistant bus bar of Figure 6.

The fire-resistant bus bar 100' in FIG. 6(a) adopts a bus bar with the same or similar structure as the conventional bus bar as shown in FIG. 7 as the bus bar conductor portion 110. That is, the metal conductor portion of the bus bar conductor portion 110 is coated with an insulating layer 140 made of a material different from the fireproof silicon coating layer 120. Therefore, in the embodiment of FIG. 6(a), two layers of the insulating layer 140 and the fire-resistant silicone coating layer 120 of different insulating materials are provided, so that the insulation performance of the fire-resistant bus bar 100' is further improved. do.

The material of the insulating layer 140 may be heat-resistant silicone rubber, epoxy, such as a conventional busbar covering layer, or a tape or sheet of a heat-resistant material such as glass fiber or mica sheet. Additionally, various coating methods may be used, such as wrapping an insulating layer tape on the bus bar conductor portion 110, coating, or injection molding on the bus bar.

In the case of the embodiment shown in FIG. 6(a), insulation is improved to some extent even in ignition situations, but more specifically, insulation is greatly improved in normal operation situations of the battery pack. Additionally, an advantage of this embodiment is that the fire-resistant bus bar of the present invention can be easily manufactured by directly applying a commercially available conventional bus bar.

The fire-resistant bus bar 100" of the embodiment of Figure 6(b) is anodized on the inner and outer surfaces of the metal case 130 to reinforce insulation. Except for the anodized oxidation treatment, , provided with a bus bar conductor portion 110 and a fire-resistant silicon coating layer 120 surrounding the bus bar conductor portion 110, and receiving the bus bar conductor portion 110 and the fire-resistant silicon coating layer 120, It is the same as the first embodiment in that a metal case 130 is provided on both sides with openings through which both ends of the bus bar conductor portion are exposed.

The embodiment of FIG. 6(b) is disclosed in that the bus bar is provided with a different insulating layer 140 in the same manner as in FIG. 6(a). However, as shown in FIG. 5, it is of course possible to anodize the metal case of the refractory bus bar provided with the bus bar conductor portion 110, which is formed only of the metal conductor portion without any other insulating layer 40. However, in the case of Figure 6(b), a total of three insulating layers are provided, that is, the insulating layer 40, the fire-resistant silicon coating layer 120, and the anodized layer (oxide film 133), so the insulating performance of the fire-resistant silicon This has the advantage of being maximized.

As described above, anodizing improves the corrosion resistance and wear resistance of non-ferrous metal products. For example, when the metal case is aluminum, the aluminum is placed on the anode and electrolyzed in a diluted acid solution, and the oxygen generated at the anode forms an insulating oxide film 133 on the aluminum surface, that is, a metal oxide (alumina (Al) ₂ O ₃ )) is formed. Therefore, the insulation of the fire-resistant bus bar 100" of this embodiment is further improved.

The anodizing treatment can be performed on the inner or outer surface of the metal case 130, or on both the inner and outer surfaces as shown in FIG. 6(b). If the inner surface of the metal case 130 is anodized, the bus bar conductor portion 110 can be double insulated along with the fireproof silicon coating layer 120 inside the metal case. By anodizing the outer surface of the metal case, the electrical insulation performance of external metal parts can be improved. All of the above effects can be achieved by anodizing both the inner and outer surfaces of the metal case.

[Battery Pack]

Figure 8 is a schematic diagram showing an example of a battery pack structure in which the fire-resistant bus bar of the present invention is installed, Figure 9 is a schematic diagram showing another example of a battery pack structure in which the fire-resistant bus bar of the present invention is installed, and Figures 10 and 11 are the present invention. This is a perspective view and side cross-sectional view showing the fire-resistant bus bar of the invention installed in a battery pack.

The fire-resistant bus bar (100, 100', 100") of the present invention described above includes a fire-resistant silicon coating layer 120 that is ceramicized at a high temperature, and a metal case 130 that surrounds the fire-resistant silicon coating layer to maintain its shape, Therefore, when applied to a battery pack where internal combustion may occur, the safety of the battery pack can be greatly improved.

The fire-resistant bus bar may be used, for example, to electrically connect a plurality of battery modules accommodated in a battery pack to each other. In this case, the fire-resistant bus bar can electrically connect terminal portions of adjacent battery modules. Alternatively, the fire-resistant bus bar can be used to connect battery modules with external electrical devices.

In particular, the high-voltage terminals of the battery module generate relatively high heat due to high current. Accordingly, when a flame occurs inside the pack, higher heat may be concentrated in the high voltage terminal. Therefore, the fire-resistant bus bar of the present invention is suitable for application as a high-voltage bus bar that electrically connects the high-voltage terminals of a plurality of battery modules.

The battery pack 1000 of the present invention includes a plurality of battery modules 200; A flame prevention partition 300 installed between the battery modules; It may include the above-described fire-resistant bus bars (100, 100', 100") that electrically connect the battery module; and a pack housing 400 that accommodates the battery module and a flame-prevention partition.

Referring to FIG. 8, a plurality of battery modules 200 are shown being accommodated in the 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 derived 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 interbus bar. A fire-resistant bus bar according to the present invention may be applied to electrically connect the plurality of battery modules.

Meanwhile, in Figures 8 and 9, a typical battery module 200 is disclosed in which the module housing completely surrounds the top, bottom, left, and right sides of the battery cell stack. However, it is not limited to this, for example, a battery module having a module housing of a modular structure configured to open at least one of the top, bottom, left, and right sides of the cell stack, or a battery module in which the entire top, bottom, left, and right sides of the cell stack are open. The fireproof bus bar of the present invention can also be applied to battery cell blocks. In this way, cell blocks or battery modules with all or part of the module housing omitted can be installed in the battery pack to form a battery pack with a so-called cell-to-pack structure. The fire-resistant bus bars (100, 100', 100") of the present invention can be used for electrical connection of cell blocks installed in a battery pack of this cell-to-pack structure or battery modules of a module-less structure.

In order to prevent flame spread between adjacent modules, the battery pack 1000 may include a flame prevention partition 300 installed between battery modules. The flame prevention partition 300 may be made of metal to ensure rigidity. The flame prevention partition 300 functions to prevent the flame from spreading to adjacent modules when a fire occurs in one module. In this case, the flame prevention partition 300 may be provided with a bus bar installation through hole 310 or a bus bar installation groove 320. Figure 8 shows that the flame prevention partition 300 is provided with a bus bar installation through hole 310, and Figure 9 shows that the flame prevention partition 300 is provided with a bus bar installation groove 320. In terms of flame prevention and airtightness, a partition wall provided with a bus bar installation through hole 310 as shown in FIG. 8 is advantageous. Since the top of the bus bar installation groove 320 in FIG. 9 is open, it is advantageous to install the bus bar and perform electrical connection work on the bus bar.

The fireproof bus bars (100, 100', 100") may be seated in the bus bar installation through hole 310 or the bus bar installation groove 320. At this time, the Both ends 111 of the bus bar conductor portion 110 may be electrically coupled to terminal portions 210 and 220 of the battery module 200 located on both sides of the flame prevention partition 300.

10 and 11 show the fire-resistant bus bar 100 electrically connecting the battery module 200 within the battery pack 1000. A flame-prevention partition wall 300 is located between neighboring battery modules 200, and the flame-prevention partition wall is provided with a bus bar installation through hole 310. The metal case 130 of the fire-resistant bus bar 100 of the present invention is inserted into the through hole. In this case, the shape of the metal case 130 of the fireproof bus bar is formed to correspond to the shape of the bus bar installation through hole 310 (or bus bar installation groove). Therefore, the fire-resistant bus bar 100 of the present invention can be airtightly adhered to the flame prevention partition wall 300. Accordingly, the airtightness of the battery pack can be further improved. In addition, even when the bus bar installation through hole or the bus bar installation groove has a sharp edge due to processing, the metal case 130 protects the fireproof silicon coating layer 120 and the bus bar conductor portion 110 by surrounding them. do. In other words, the insulation strength and airtightness of the fireproof bus bar are further improved by the metal case.

In this case, the insulation of the refractory bus bar 100" can be further improved by anodizing at least one side of the metal case as in the second embodiment.

Meanwhile, when a flame occurs within the battery pack 1000, in the fire-resistant bus bar of the present invention, the fire-resistant silicon coating layer 120 surrounding the bus bar conductor portion 110 is ceramicized to form a dense sintered body. In other words, it does not burn out or turn to ash at high temperatures of 500°C or higher like conventional heat-resistant silicon, but becomes ceramic and maintains its shape. Accordingly, the fire-resistant silicone coating layer stably supports the bus bar conductor portion even when a flame occurs. The metal case not only maintains the shape of the refractory silicon coating layer, but also prevents flames from contacting the refractory silicon coating layer, thereby preventing deformation of the refractory silicon and further strengthening the insulating and airtight properties.

[Experimental example]

(Experimental Example 1)

Fireproof silicon consisting of 50% by weight of the silicon compound of Formula 1, 20% by weight of quartz, and 30% by weight of pure silicon dioxide is applied to a busbar conductor section made of copper with a predetermined thickness having a predetermined cross-sectional area selected from the range of 0.5 to 3 mm ^2. It was coated with. The fireproof silicon-coated busbar of Example 1 was manufactured by exposing both ends of the busbar conductor portion other than the coating portion.

The length of the bus bar conductor portion and the exposed length of both ends were the same as in Example 1, and a glass fiber tape (3M 361) was wound a total of two times over the central portion of the bus bar conductor portion. The bus bar of Comparative Example 1 was manufactured by making the coating thickness of the wound glass fiber tape almost the same as the coating thickness of the fireproof silicon.

As the busbar of Comparative Example 2, a mica tape made of natural mica, phlogopite mica, was wound once around the central portion of the busbar conductor portion, and the glass fiber tape of Comparative Example 1 was wound once thereon. The length of the bus bar conductor portion and the exposed length of both ends are the same as Example 1 and Comparative Example 1.

In order to test the insulation characteristics (insulation maintenance performance) in the event of a fire, copper wire was wound with the same number of turns around the covering part (coating part, tape winding part) of the bus bars of Examples 1 to Comparative Example 2, and the outermost part of the covering part was wrapped. One end of the copper wire was connected to the negative terminal of the withstand voltage tester, and one end of the bus bar conductor was connected to the positive terminal of the withstand voltage tester. With a voltage of 1000 V applied to the bus bars using a withstand voltage tester, the entire surface of the bus bars was uniformly heated using a large torch with a flame temperature of 1100 to 1150°C.

The insulation fail time at which the insulation state is destroyed, that is, a short circuit occurs, was measured under the above voltage and heating temperature conditions, and the measurement results are shown in Table 1 below.

Experimental Example 1 Busbar configuration Insulation Fail Time Comparative Example 1 Copper busbar conductor + glass fiber tape 1 minute 20 seconds Comparative Example 2 Copper busbar conductor + mica tape + glass fiber tape + 4 minutes 25 seconds Example 1 Copper busbar conductor + fireproof silicon 7 minutes 20 seconds

As shown in Table 1, the bus bar with the fireproof silicon coating layer according to the present invention had the longest insulation failure time, and showed a significant difference in insulation failure time from Comparative Examples 1 and 2.

Therefore, it can be seen that the insulating properties of the fire-resistant bus bar of the present invention filled with the above-mentioned fire-resistant silicone coating layer in the metal case are very excellent. Example 1 tested the insulation performance without a metal case, and it is clear that when a metal case is installed outside the fireproof silicon coating layer, the insulation performance will be further improved against high external temperatures because the fireproof silicon is not directly exposed to the flame. something to do.

(Experimental Example 2)

Fireproof silicone with the composition shown in Table 2 below was prepared by varying the weight ratio of the silicon compound of Formula 1 and the weight ratio of the metal oxide.

The fireproof silicon of Examples 1 to 5 was coated to a predetermined thickness on the copper busbar conductor under the same conditions as in Experimental Example 1, and a copper wire was wound on the busbar coating layer and connected to a withstand voltage tester under the same conditions as in Experimental Example 1. .

In addition, 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.

Experimental Example 2 Composition of fireproof silicone coating layer Insulation Fail Time Example 1 Silicone compound 50% by weight: Metal oxide 50% by weight
(Quartz: 20% by weight, pure silicon dioxide: 30% by weight) 7 minutes 20 seconds Example 2 Silicone compound 50% by weight: Metal oxide 25% by weight
(Quartz: 20% by weight, pure silicon dioxide: 15% by weight) 6 minutes 55 seconds Example 3 Silicone compound 50% by weight: Metal oxide 75% by weight
(Quartz: 30% by weight, pure silicon dioxide: 45% by weight) 8 minutes 25 seconds Example 4 Silicone compound 50% by weight: Metal oxide 20% by weight
(Quartz: 10% by weight, pure silicon dioxide: 10% by weight) 6 minutes Example 5 Silicone compound 50% by weight: Metal oxide 80% by weight
(Quartz: 35% by weight, pure silicon dioxide: 45% by weight) 8 minutes 40 seconds

In Examples 1 to 5, the weight ratio of the silicon compound and the metal oxide was 1:1, 1:0.5, 1:1.5, 1:0.4, and 1:1.6.

All examples have much longer insulation fail times than Comparative Examples 1 and 2. However, in the case of Example 4 where the weight ratio was less than 0.5, the insulation failure time was somewhat short, which is believed to be because the metal oxide was not sufficient and the creation of a ceramic structure with a high-density crystal structure at high temperature was somewhat insufficient.

In addition, in the case of Example 5 where the weight ratio was 1.6, the insulation failure time was sufficiently long, but the flexibility of the refractory silicon decreased at room temperature due to excessive metal oxide, making it difficult to follow and cover the bus bar conductor.

Above, the present invention has been described in more detail through drawings and examples. However, since the configurations described in the drawings or examples described in this specification are only one embodiment of the present invention and do not represent the entire technical idea of the present invention, at the time of filing this application, various equivalents and It should be understood that variations may exist.

100,100',100": Fireproof bus bar
110: Busbar conductor part
120: Fireproof silicone coating layer
130: Metal case
131: opening
132: Hook coupling part
133: Oxide film
200: Battery module
210,220: Terminal part
300: Bulkhead for flame prevention
310: Busbar installation through hole
320: Busbar installation groove
400: pack housing
1000: Battery pack

Claims (13)

Busbar conductor section;
A fire-resistant silicon coating layer that surrounds the bus bar conductor portion except for both ends and is ceramicized at a high temperature to support the bus bar conductor portion; and
A fireproof bus bar comprising a metal case in which the busbar conductor portion and the fireproof silicon coating layer are accommodated, and having openings on both sides through which both ends of the busbar conductor portion are brought out to the outside.
According to paragraph 1,
The refractory silicon is a refractory bus bar that becomes ceramic at a temperature of 500 to 1700°C.
According to paragraph 1,
The fire-resistant silicone includes a silicone resin containing a silicone compound represented by the following formula (1); A refractory busbar characterized in that it is ceramicized by sintering a metal oxide containing silicon oxide:
[Formula 1]

In Formula 1, m and n are each integers of 10 to 30.
According to paragraph 3,
A refractory bus bar containing the silicone resin and metal oxide in a weight ratio of 1:0.5 to 1.5.
According to paragraph 3,
The metal oxide containing silicon oxide is a refractory bus bar containing one or more of pure silicon dioxide, silica, quartz, silica, tridymite, and keatite.
According to paragraph 1,
The metal case has an upper case and a lower case, and the upper and lower cases are connected by a hook connection.
According to paragraph 1,
A fire-resistant bus bar comprising an insulating layer made of a material different from the fire-resistant silicon coating layer between the bus bar conductor portion and the fire-resistant silicon coating layer.
According to paragraph 1,
The metal case is a fireproof bus bar in which at least one of the inner and outer sides is anodized.
According to paragraph 1,
The metal case is a fireproof bus bar made of one of aluminum, steel, and stainless steel.
According to paragraph 1,
The fire-resistant bus bar is a high-voltage bus bar and a fire-resistant bus bar that electrically connects high-voltage terminals of a plurality of battery modules.
A plurality of battery modules;
A flame prevention partition installed between the battery modules;
A fireproof bus bar according to any one of claims 1 to 10 electrically connecting the battery module; and
A battery pack including a pack housing accommodating the battery module and a flame prevention partition.
According to clause 11,
The flame prevention partition has a bus bar installation through hole or a bus bar installation groove,
The metal case of the fireproof bus bar is seated in the bus bar installation through hole or bus bar installation groove,
A battery pack in which both ends of the bus bar derived from the opening of the metal case are electrically coupled to terminal parts of a battery module located on both sides of the flame prevention partition.
According to clause 12,
The metal case is a battery pack formed to correspond to the shape of the bus bar installation through hole or the bus bar installation groove.

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