Battery disconnect unit and lithium secondary battery including the same

Abstract

The present invention relates to a battery cutoff unit that can be disposed inside a battery pack, etc., and to a battery cutoff unit that maintains performance and improves stability by preventing or delaying the spread of a fire inside the battery pack. The battery cutoff unit according to the present invention comprises: a housing designed to accommodate electrical components inside; and a space formed inside the housing to accommodate a fire extinguishing substance, wherein the fire extinguishing substance accommodated in the internal space is prevented from being released to the outside when the temperature is below a preset temperature, and the fire extinguishing liquid is discharged to the outside when the temperature is above the preset temperature.

Description

Technology Field

[0001] This application is based on Korean Patent Applications No. 10-2023-0035481 and No. 10-2023-0153043, which were filed with the Korean Intellectual Property Office on March 17, 2023 and November 7, 2023, respectively, and whose contents are incorporated in whole into this application by reference herein, and claims priority thereof.

[0002] The present invention relates to a battery cutoff unit, and more specifically, to a battery cutoff unit used in a battery module or battery pack comprising a secondary battery capable of charging and discharging. Background Technology

[0003] Recently, with rising energy prices due to the depletion of fossil fuels and growing concern over environmental pollution, the demand for eco-friendly alternative energy sources has become an indispensable factor for future life. Accordingly, research on various power generation technologies, such as solar, wind, and tidal power, is ongoing, and there is also significant interest in power storage devices, such as batteries, to utilize this generated electrical energy more efficiently.

[0004] Furthermore, as technological development and demand for battery-powered electronic mobile devices and electric vehicles increase, the demand for batteries as an energy source is rapidly rising, and accordingly, much research is being conducted on batteries capable of meeting various requirements.

[0005] Batteries that store electrical energy can generally be classified into primary and secondary batteries. Primary batteries are disposable, consumable batteries, whereas secondary batteries are rechargeable batteries manufactured using materials capable of repeating oxidation and reduction processes between the electric current and the material. In other words, when a reduction reaction is performed on the material by the electric current, the power is charged, and when an oxidation reaction is performed, the power is discharged; electricity is generated as this charging and discharging cycle is repeatedly performed.

[0006] Secondary batteries can be classified into cylindrical cells, pouch cells, prismatic cells, etc., depending on their shape. Among these, pouch cells may include an electrode assembly in which a positive electrode, a negative electrode, a separator, etc., are stacked inside a pouch.

[0007] Meanwhile, multiple secondary batteries described above may be housed within a frame to form a battery module. Additionally, multiple battery modules may form a battery pack. In this case, the battery module or battery pack may include a Battery Disconnect Unit (BDU). For example, in a battery pack, the Battery Disconnect Unit may be positioned between a power converter and a battery module to cut off power to the battery module in situations such as when the current exceeds a set range. The stability of the battery pack can be improved by the Battery Disconnect Unit. The problem to be solved

[0008] The objective of the present invention is to provide a battery cutoff unit capable of continuously weakening a fire for a certain period of time when a fire occurs in a battery. means of solving the problem

[0009] A battery cutoff unit according to an embodiment of the present invention comprises: a housing designed to accommodate electrical components inside; and at least one space formed to accommodate a fire extinguishing substance inside the housing body, wherein the fire extinguishing substance accommodated in the space is prevented from being released to the outside of the housing when the temperature is below a preset temperature and is configured to be released to the outside when the temperature is above the preset temperature.

[0010] The above housing may further include a passage, which is a channel extending from a space where the fire extinguishing material is placed to the outside, and the housing may further include a cover placed in the passage to prevent the external release of the fire extinguishing material at a temperature below a preset temperature.

[0011] The above cover may form a flow path inside so that the extinguishing substance can pass through the passage at a temperature above the above preset temperature.

[0012] The above cover may include fire-resistant silicone.

[0013] The above-mentioned refractory silicone may be configured such that it expands in volume and hardens at a temperature above the above-mentioned preset temperature, thereby forming a gap inside, and the fire extinguishing material passes through the passage through a flow path formed along the gap.

[0014] The above housing may further include a first housing and a second housing designed to be combined with the first housing to accommodate the electrical components.

[0015] The above-mentioned extinguishing material may include a first extinguishing liquid disposed in a first space formed inside the first housing and a second extinguishing liquid disposed in a second space formed inside the second housing.

[0016] In the first housing, a first passage is formed extending from a first space in which the first extinguishing liquid is disposed to the outside, and in the second housing, a second passage, which is a channel extending from a second space in which the second extinguishing liquid is disposed to the outside, may be formed.

[0017] The first passage extends from the first space where the first extinguishing liquid is placed toward the electrical component, and the second passage may extend from the second space where the second extinguishing liquid is placed toward the electrical component.

[0018] The first housing may include a first cover disposed in the first passage to prevent the external discharge of the first extinguishing liquid below the preset temperature, and the second housing may include a second cover disposed in the second passage to prevent the external discharge of the second extinguishing liquid below the preset temperature.

[0019] The second passage may include a lower passage formed by extending in one direction from one side of the space where the second extinguishing liquid is placed, and a side passage formed by extending in another direction from the other side of the second space where the second extinguishing liquid is placed.

[0020] The second housing may include a lower cover disposed in the lower passage and a side cover disposed in the side passage.

[0021] The above housing may be made of any one selected from aluminum, stainless steel, and alloy.

[0022] The above electrical component may include one or more relays configured to open or close an electrical circuit connected to a battery module.

[0023] The above electrical component may further include a busbar connecting the relays to each other.

[0024] The above preset temperature may be 300℃ or higher and 400℃ or lower.

[0025] A battery cutoff unit according to an embodiment of the present invention includes an electrical component and a housing designed to accommodate the electrical component, and the housing may include a cover having a space formed therein for accommodating a fire extinguishing substance, a gap formed therein at a temperature above a preset temperature, and a flow path formed along the gap through which the fire extinguishing substance moves from the space toward the outside of the housing.

[0026] In another embodiment of the present invention, a secondary battery pack including the battery cutoff unit may be provided. Effects of the invention

[0027] A battery cutoff unit according to the present invention comprises a housing designed to accommodate electrical components inside, and at least one space formed to accommodate a fire extinguishing substance inside the housing body, wherein the fire extinguishing substance accommodated in the space is prevented from being released to the outside of the housing when the temperature is below a preset temperature and is configured to be released to the outside when the temperature is above the preset temperature.

[0028] Accordingly, the fire extinguishing material inside the battery cutoff unit leaks out, which can delay thermal runaway.

[0029] In addition, it can prevent or delay the spread of a fire inside the battery pack to the outside.

[0030] In addition, it can continuously supply fire extinguishing substances to the fire for a certain period of time.

[0031] In addition, it can delay the melting and loss of the battery cutoff unit's case.

[0032] This prevents the battery cutoff unit from losing function due to fire.

[0033] In addition, it is possible to secure time for the safety devices inside the battery pack to operate.

[0034] Through this, the stability of the battery pack can be improved.

[0035] The effects according to the present invention are not limited to those exemplified above, and various other effects are included in this specification. Brief explanation of the drawing

[0036] FIG. 1 is an exploded perspective view schematically illustrating a battery cutoff unit according to Embodiment 1 of the present invention. FIG. 2 is a schematic perspective view illustrating a battery pack including a battery cutoff unit according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view showing a battery cut-off unit in an assembled state according to Example 1 of the present invention, cut along A-A' of FIG. 1. Figure 4 is an enlarged view schematically illustrating the discharge of the extinguishing liquid by enlarging B of Figure 3. FIG. 5 is a cross-sectional view showing a battery cut-off unit in an assembled state according to Embodiment 2 of the present invention, cut along A-A' of FIG. 1. In parts of the attached drawings, corresponding components are given the same reference numerals. Those skilled in the art understand that the drawings are intended to illustrate elements simply and clearly and are not necessarily drawn to scale. For example, to aid in understanding various embodiments, the dimensions of some elements depicted in the drawings may be exaggerated compared to others. Additionally, elements of known technology that are useful or essential in commercially viable embodiments may often be omitted so as not to hinder the spirit of the various embodiments of the present invention. Specific details for implementing the invention

[0037] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0038] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0039] Furthermore, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0040] As used herein, "about," "approximately," and "substantially" are used to mean a range of numerical values ​​or degrees or approximations thereof, taking into account inherent manufacturing and material tolerances, and are used to prevent an infringer from unfairly exploiting the disclosure in which precise or absolute figures provided to aid in understanding the invention are mentioned.

[0041] Generally, secondary batteries, also known as rechargeable batteries, are formed with components such as battery cells, modules, battery packs, wires, battery disconnect units (BDUs), battery management systems (BMS), and busbars. In such a configuration, for example, if a problem occurs in a specific cell within the battery pack, a significant amount of heat may be generated in that specific cell and conducted to surrounding cells, eventually leading to a fire. A fire in such a cell can cause a fire in the module.

[0042] The Battery Disconnect Unit (BDU) is typically located near the module, and its casing is made of, for example, aluminum or plastic. Additionally, since electrical components such as relays and busbars inside the Battery Disconnect Unit are usually fixed to the casing, an electrical short circuit occurs between the surrounding pack structures when the casing structure of the Battery Disconnect Unit is destroyed by fire. In such a situation, an electrical closed circuit is formed within the pack structure, accelerating thermal runaway. When such thermal runaway occurs, the temperature rises to, for example, 1,200 °C, making it impossible for materials such as aluminum and plastic to support the structure of the Battery Disconnect Unit.

[0043] Conventional battery cutoff units had the problem of being unable to suppress a fire or delay its spread in the event of a fire. Furthermore, this problem led to an additional issue where the internal insulation performance of the battery cutoff unit could not be properly utilized.

[0044] Accordingly, a battery cutoff unit according to one embodiment of the present invention is designed to prevent or delay the spread of a fire inside a battery pack, thereby maintaining the performance of the battery pack and improving stability.

[0045] Various embodiments of the battery cutoff unit of the present invention are described in detail below together with the attached drawings.

[0046] Example 1

[0047] FIG. 1 is an exploded perspective view schematically illustrating a battery cutoff unit (10) according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view schematically illustrating a battery pack (P) including a battery cutoff unit (10) according to Embodiment 1 of the present invention.

[0048] A battery cutoff unit (10) according to Embodiment 1 of the present invention may include a housing (100) and an electrical component (500).

[0049] Referring to FIG. 1, the battery cutoff unit (10) includes a housing (100) having a structure capable of accommodating an electrical component (500) inside it. That is, the electrical component (500) can be arranged to be accommodated within the housing (100). According to one embodiment, the housing (100) of the battery cutoff unit (10) includes a first housing (110) and a second housing (120), and the first housing (110) and the second housing (120) are combined to have a structure that accommodates the electrical component (500). Here, the battery cutoff unit (10) may refer to a component that cuts off the power of the battery pack (P) for the safety of the battery pack (P) as illustrated in FIG. 2 when a current exceeding a preset range occurs. Additionally, the electrical component (500) may refer to a set of components for the operation of the battery cutoff unit (10). For example, to cut off power to the battery pack (P) (see FIG. 2), the electrical component (500) can cut off the connection between the battery module (M) containing a plurality of secondary batteries and the power converter.

[0050] Referring to FIG. 2, a battery cutoff unit (10) according to Embodiment 1 of the present invention may be disposed inside a battery pack (P). For example, the battery cutoff unit (10) may be disposed at one end or both ends inside the battery pack (P). Additionally, one or more battery modules (M) may be disposed inside the battery pack (P) further inward than the battery cutoff unit (10). Furthermore, a connector (not shown) capable of connecting the battery pack (P) to the outside may be disposed near the battery cutoff unit (10).

[0051] FIG. 3 is a cross-sectional view showing a battery cut-off unit (10) in an assembled state according to Embodiment 1 of the present invention, cut along A-A' of FIG. 1. That is, FIG. 3 is a cross-sectional view of a battery cut-off unit (10) according to Embodiment 1 of the present invention, cut along A-A' of FIG. 1.

[0052] As an example of a configuration for preventing the spread of fire, the housing (100) of the battery cutoff unit (10) according to Embodiment 1 of the present invention may include a space (200) capable of accommodating a fire extinguishing liquid (300). For example, the space (200) may be formed to be embedded inside each of the first housing (110) and the second housing (120) of the housing (100), and the fire extinguishing liquid (300) may be placed in this space (200) formed inside each of the first housing (110) and the second housing (120). At this time, the fire extinguishing liquid (300) may include a substance that exerts a fire suppression effect and may have fluidity.

[0053] A fire extinguishing liquid (300) placed in the internal space (200) of each of the first housing (110) and the second housing (120) of the housing (100) can be discharged to the outside of the housing (100) at a temperature above a preset temperature. Here, the preset temperature may refer to a temperature at which there is a risk that the battery cutoff unit (10) will lose its function due to fire. Accordingly, when the temperature of the battery cutoff unit (10) reaches the preset temperature, the fire extinguishing liquid (300) can be discharged to the outside of the housing (100) to exert a fire extinguishing effect. For example, the preset temperature may be approximately 300°C to 400°C. According to one embodiment, the preset temperature may be a specific temperature between 300°C and 400°C.

[0054] In the battery cutoff unit (10) according to Embodiment 1 of the present invention, since the fire extinguishing liquid (300) is placed in the internal space (200) of the housing (100) which is composed of a first housing (110) and a second housing (120), it can maintain the same function in normal times and perform a fire extinguishing function in the event of a fire, thereby improving safety.

[0055] The housing (100) of the battery cutoff unit (10), that is, the first and second housings (110, 120), may be made of a material with a high melting point so as not to be destroyed by heat in the event of a fire. For example, the housing (100) may be made of metal. According to one embodiment, the housing (100) may be made of aluminum (Al), stainless steel (STS), an alloy containing a plurality of metals, etc. The housing (100) may be made of aluminum (Al) in consideration of manufacturing processes such as formability.

[0056] According to Embodiment 1 of the present invention, the housing (100) formed by the first housing (110) and the second housing (120) may further include a cover (400). In this regard, a passage, which is a channel through which a extinguishing liquid (300) can move to the outside of the first housing (110) and the second housing (120), may be further formed inside each of the first housing (110) and the second housing (120) of the housing (100). According to one embodiment, the passage of the housing (100) may be formed in a tubular shape extending from the space (200) where the extinguishing liquid (300) is placed to the outside of the space (200). Meanwhile, the cover (400) of the housing (100) may be placed in the passage of the extinguishing liquid (300) so as to prevent the extinguishing liquid (300) from being released outside at a temperature below a preset temperature. According to one embodiment, the cover (400) of the housing (100) may be formed at an inlet for injecting a extinguishing liquid (300) into the space (200). That is, the extinguishing liquid (300) may be contained within the space (200) of the housing (100) by the cover (400) under conditions below a preset temperature, and the extinguishing liquid (300) may be discharged from the space (200) to the outside through a passage under conditions above a preset temperature.

[0057] As explained above, the preset temperature can be a specific temperature between 300°C and 400°C.

[0058] The cover (400) may have a cross-section nearly identical to the cross-section of the passage so as to prevent the discharge of the extinguishing liquid (300) under conditions below a preset temperature. However, the length to which the cover (400) extends may be shorter than the length of the passage, or the cover (400) may reach the outer surface of the housing (100) along the passage.

[0059] FIG. 4 is an enlarged view of FIG. 3B schematically illustrating the appearance of the extinguishing liquid (300) being discharged from the space (200).

[0060] The cover (400) of the housing (100), formed by the first housing (110) and the second housing (120), may have a flow path formed inside so that the extinguishing liquid (300) can move at a temperature above a preset temperature. That is, at a temperature above a preset temperature, the extinguishing liquid (300) is discharged to the outside of the housing (100) through the flow path formed inside the cover (400), thereby delaying or preventing the spread of fire.

[0061] As an example of a configuration for forming a flow path at a preset temperature or higher, the cover (400) of the first housing (110) and the second housing (120) may include silicone, and for example, the cover (400) may be made of fire-resistant silicone.

[0062] Fireproof silicone can have fire resistance and can be ceramicized at a preset temperature or higher. Here, fire resistance may refer to the property of not burning easily and withstanding fire, and ceramicization may refer to a state of hardening due to heat. That is, the cover (400) is made of fireproof silicone and can be ceramicized while withstanding fire. Therefore, fireproof silicone can be ceramicized when it reaches a specific temperature of 300°C or higher and 400°C or lower.

[0063] Referring to FIG. 4, the fire-resistant silicone is ceramicized at a temperature above a preset temperature and expands, forming a gap inside, and the fire extinguishing liquid (300) can pass through the passage formed along this gap. For example, as the cover (400) hardens through ceramicization, the inside cracks, and the fire extinguishing liquid (300) can flow through the cracked part. That is, the gap in the cover (400), which is the cracked part, can serve as a passage for the fire extinguishing liquid (300) to move from the space (200) to the outside of the housing (100). Since the passage, which is the channel for the fire extinguishing liquid (300), is connected from the space (200) where the fire extinguishing liquid (300) is received to the outside of the housing (100), the fire extinguishing liquid (300) can be discharged to the outside of the housing (100) as it passes through the passage.

[0064] The housing (100) of the battery cutoff unit (10) according to Embodiment 1 of the present invention includes a cover (400) made of a material that can be ceramicized at a preset temperature or higher, so that a fire extinguishing liquid (300) can be selectively used when necessary. In addition, since the fire extinguishing liquid (300) can be continuously discharged for a certain period of time, the spread of fire can be efficiently delayed or prevented.

[0065] Referring again to FIGS. 1 and 3, according to one embodiment, a first housing (110) may be placed on the upper part of an electrical component (500), and a second housing (120) may be placed on the lower part of an electrical component (500).

[0066] Accordingly, the extinguishing liquid (300) may include a first extinguishing liquid (310) disposed in a space (200) formed inside the first housing (110) and a second extinguishing liquid (320) disposed in a space (200) formed inside the second housing (120). For example, the first extinguishing liquid (310) and the second extinguishing liquid (320) may each be disposed in a plurality of spaces (200) inside the first housing (110) and the second housing (120), respectively.

[0067] A first passage may be formed in the first housing (110) as a channel extending from the space (200) where the first fire extinguishing liquid (310) is placed to the outside, and a second passage may be formed in the second housing (120) as a channel extending from the space where the second fire extinguishing liquid (320) is placed to the outside. Additionally, the first housing (110) may include a first cover (410) placed in the first passage, and the second housing (120) may include a second cover (420) placed in the second passage. That is, the first cover (410) can prevent the first fire extinguishing liquid (310) from being discharged outside the first housing (110) at a temperature below a preset temperature, and the second cover (420) can prevent the second fire extinguishing liquid (320) from being discharged outside the second housing (120) at a temperature below a preset temperature.

[0068] In the battery cutoff unit (10) according to Embodiment 1 of the present invention, a plurality of fire extinguishing liquids (300) are arranged on both sides of the electrical component (500) so that the fire extinguishing liquids (300) can be discharged over a wider range when a fire occurs.

[0069] Meanwhile, the first passage formed in the first housing (110) and the second passage formed in the second housing may have a shape that extends toward the electrical component (500). Accordingly, when the fire extinguishing liquid (300) passes through the passage through the flow path formed by the gap in the cover (400), it can be discharged to the place where the electrical component (500) is placed. Since the passage is formed to extend toward the electrical component (500), the fire extinguishing liquid (300) can efficiently prevent the electrical component (500) from failing to function due to fire.

[0070] The electrical components (500) of the battery cutoff unit (10) according to Embodiment 1 of the present invention may include a relay (510) and a busbar (520). The relay (510) may function to open or close an electrical circuit connected to the battery module (M). Additionally, when the electrical components (500) include a plurality of relays (510), the busbar (520) may electrically connect the plurality of relays (510) to each other.

[0071] Example 2

[0072] FIG. 5 is a cross-sectional view showing a battery cut-off unit in an assembled state according to Embodiment 2 of the present invention, cut along the line at the same position and direction as A-A' in FIG. 1. That is, FIG. 5 is a cross-sectional view of a battery cut-off unit (10') according to Embodiment 2 of the present invention, cut along the same position and direction as A-A' in FIG. 1.

[0073] In the following, the description of the configuration identical to that of the battery cutoff unit (10) according to Embodiment 1 of the present invention is omitted, and the description focuses on the differences. In this regard, the shape of the passage in the battery cutoff unit according to Embodiment 2 of the present invention may differ from that of Embodiment 1. Specifically, the direction in which the passage according to Embodiment 2 extends and the position in which it is placed may differ from that of Embodiment 1.

[0074] A housing (100') according to Embodiment 2 of the present invention may include a first housing (110') and a second housing (120'). The first housing (110') may include a first fire extinguishing liquid (310') disposed in a space (210') formed inside and a first cover (410') disposed in a first passage formed extending from the space (210') to the outside. Additionally, the second housing (120') may include a second fire extinguishing liquid (320') disposed in a space (220') formed inside and a second cover (420') disposed in a second passage formed extending from the space (220') to the outside.

[0075] At this time, the first passage and the second passage may extend in different directions. Referring to FIG. 5, the first passage may extend from the space (210') where the first fire extinguishing liquid (310') is placed toward the electrical component (500), and the second passage may extend from the space (220') where the second fire extinguishing liquid (320') is placed toward the electrical component (500). Therefore, in the event of a fire, the first fire extinguishing liquid (310') and the second fire extinguishing liquid (320') may be discharged to different locations.

[0076] In the case where the battery cutoff unit (10') according to Embodiment 2 of the present invention is exposed to a temperature above a preset temperature due to fire, the first extinguishing liquid (310') can prevent electrical components (500) inside the battery cutoff unit (10') from being lost to fire. Additionally, the second extinguishing liquid (320') can delay or prevent the spread of fire to the outside of the battery cutoff unit (10'). Thus, the second extinguishing liquid (320') can delay thermal runaway inside the battery pack (P). Here, the preset temperature can be a specific temperature of approximately 300°C or higher and 400°C or lower.

[0077] As an example of a configuration for sending the second digestive liquid (320') over a wide range, the second passage according to Example 2 of the present invention may include a lower passage and a side passage.

[0078] Referring to FIG. 5, the lower passage may be formed by extending in one direction from one side of the internal space (220') of the second housing (120') in which the second fire extinguishing liquid (320') is placed. Here, the one side may refer to the lower part of the internal space (220'), and the one direction may refer to the downward direction of the second housing (120'). Thus, the lower passage may be formed in a shape extending toward the lower part of the second housing (120'). The side passage may be formed by extending in the other direction from the other side of the internal space (220') of the second housing (120') in which the second fire extinguishing liquid (320') is placed. Here, the other side may refer to the side of the internal space (220'), and the other direction may refer to the direction toward the side of the second housing (120'). Thus, the side passage may be formed in a shape extending toward the side of the second housing (120').

[0079] In this regard, the second housing (120') according to embodiment 2 of the present invention may include a lower cover (421) and a side cover (422). In this case, the lower cover (421) may be placed in a lower passage, and the side cover (422) may be placed in a side passage.

[0080] The lower cover (421) and the side cover (422) can each prevent the second extinguishing liquid (320') from being discharged to the outside of the second housing (120') at a temperature below a preset temperature. Additionally, the lower cover (421) and the side cover (422) can each allow the second extinguishing liquid (320') to be discharged to the outside of the second housing (120') through a flow path formed along a gap formed inside the lower cover (421) and the side cover (422) at a temperature above a preset temperature. The method of creating a gap inside the lower cover (421) and the side cover (422) and the second extinguishing liquid (320') being discharged to the outside of the second housing (120') through a flow path formed along the gap is the same as described in Embodiment 1 of the present invention, so it is omitted.

[0081] The second housing (120') according to Embodiment 2 of the present invention can efficiently prevent the spread of fire outside the battery cutoff unit by releasing the second fire extinguishing liquid (320') in a more diverse direction.

[0082] Meanwhile, the battery cutoff unit (10) according to various embodiments of the present invention may be assembled to other types of battery packs or battery modules, etc., in addition to the battery pack of the type described as an example in the present invention.

[0083] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention pertains. Accordingly, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be determined by the claims. Explanation of the symbols

[0084] P: Battery pack M: Battery Module 10: Battery disconnect unit 100, 100': Housing 110, 110': 1st Housing 120, 120': 2nd Housing 200: Digestive liquid space 300, 300': Digestive liquid 310, 310': First extinguishing liquid 320, 320': Second extinguishing liquid 400, 400': Cover 410, 410': First cover 420, 420': Second cover 421: Lower cover 422: Side cover 500: Battlefield parts 510: Relay 520: Busbar

Claims

Claim 1 A battery cutoff unit comprising: a housing designed to accommodate electrical components inside; and at least one space formed inside the housing body to accommodate a fire extinguishing liquid, wherein the fire extinguishing liquid accommodated in the space is prevented from being discharged to the outside of the housing when the temperature is below a preset temperature and is discharged to the outside when the temperature is above the preset temperature, wherein the housing further comprises a passage, which is a channel extending from the space where the fire extinguishing liquid is disposed to the outside, and wherein the housing further comprises a cover disposed in the passage to prevent the discharge of the fire extinguishing liquid to the outside when the temperature is below the preset temperature. Claim 2 delete Claim 3 A battery cutoff unit according to claim 1, wherein the cover forms a flow path inside so that the extinguishing liquid can pass through the passage at a temperature above the preset temperature. Claim 4 In claim 1, the cover comprises fire-resistant silicone, a battery cutoff unit. Claim 5 A battery cutoff unit according to claim 4, wherein the fire-resistant silicone hardens while expanding in volume above the preset temperature to form a gap inside, and is configured so that the fire-extinguishing material passes through the passage through a flow path formed along the gap. Claim 6 A battery disconnection unit according to claim 1, wherein the housing further comprises: a first housing; and a second housing designed to be coupled with the first housing to accommodate the electrical components. Claim 7 A battery cutoff unit according to claim 6, wherein the extinguishing material comprises: a first extinguishing liquid disposed in a first space formed inside the first housing; and a second extinguishing liquid disposed in a second space formed inside the second housing. Claim 8 A battery cutoff unit according to claim 7, wherein the first housing has a first passage formed therein, which is a channel extending from a first space in which the first fire extinguishing liquid is disposed to the outside, and the second housing has a second passage formed therein, which is a channel extending from a second space in which the second fire extinguishing liquid is disposed to the outside. Claim 9 A battery cutoff unit according to claim 8, wherein the first passage extends toward the electrical component from the first space in which the first fire extinguishing liquid is disposed, and the second passage extends in a direction away from the electrical component from the second space in which the second fire extinguishing liquid is disposed. Claim 10 A battery cutoff unit according to claim 8, wherein the first housing comprises a first cover disposed in the first passage to prevent external discharge of the first extinguishing liquid below the preset temperature, and the second housing comprises a second cover disposed in the second passage to prevent external discharge of the second extinguishing liquid below the preset temperature. Claim 11 A battery cutoff unit according to claim 8, wherein the second passage comprises: a lower passage formed by extending in one direction from one side of the second space in which the second fire extinguishing liquid is disposed; and a side passage formed by extending in another direction from the other side of the second space in which the second fire extinguishing liquid is disposed. Claim 12 A battery cutoff unit according to claim 11, wherein the second housing comprises: a lower cover disposed in the lower passage; and a side cover disposed in the side passage. Claim 13 A battery disconnection unit according to claim 1, wherein the housing is made of any one selected from aluminum, stainless steel, and alloy. Claim 14 A battery disconnection unit according to claim 1, wherein the electrical component comprises one or more relays arranged to open or close an electrical circuit connected to a battery module. Claim 15 A battery disconnection unit according to claim 14, wherein the electrical component further comprises a busbar connecting the relays to each other. Claim 16 A battery cutoff unit according to claim 1, wherein the preset temperature is 300°C or higher and 400°C or lower. Claim 17 A battery cutoff unit comprising: an electrical component; and a housing designed to accommodate the electrical component, wherein the housing comprises a cover having a space formed therein to accommodate a fire extinguishing substance, a gap formed therein above a preset temperature, and a flow path formed along the gap through which the fire extinguishing substance moves from the space toward the outside of the housing. Claim 18 A secondary battery pack comprising the battery cutoff unit of claim 1.

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