A lithium battery deflagration suppression device and a lithium battery pack

Abstract

This application discloses a lithium battery deflagration suppression device and a lithium battery pack. The lithium battery deflagration suppression device includes: a device base, disposed corresponding to the inlet side of a pressure relief valve; a first groove recessed on one side surface of the device base, the first groove being filled with a solid fire extinguishing material layer; a gas release hole and a normal pressure gas channel recessed on one side surface of the solid fire extinguishing material layer, the gas release hole communicating with the high-pressure gas venting channel of the pressure relief valve, and the normal pressure gas channel communicating with the normal pressure gas venting channel of the pressure relief valve; the solid fire extinguishing material layer being configured to release inert gas under high temperature and high pressure; and a device shell surrounding the device base, with a gap between the device shell and the side surface of the solid fire extinguishing material layer away from the pressure relief valve to form a sandwiched gas channel; the surface of the device shell also has a gas inlet communicating with the sandwiched gas channel. This technical solution can effectively suppress the risk of eruptive open flame combustion or deflagration at the outlet of the pressure relief valve.

Description

Technical Field

[0001] This application relates to the field of lithium battery technology, and in particular to a lithium battery deflagration suppression device and a lithium battery pack. Background Technology

[0002] Currently, when lithium battery packs experience thermal runaway, the open flame or deflagration primarily occurs at the outlet of the pressure relief valve. Traditional battery pack pressure relief valves only provide a path for releasing overpressured gases, offering a single function and failing to effectively suppress open flame or deflagration caused by ejected gases. Specifically, battery pack pressure relief valves typically include a low-pressure gas guiding structure and a high-pressure opening structure. When the internal gas pressure reaches a set threshold, the pressure relief valve will fully open. Taking a 60mm diameter pressure relief valve in a certain application case as an example, it can provide a gas release capacity of up to 50L per second after opening. During battery thermal runaway, a large amount of mixed gas containing hydrogen, flammable alkanes, and a small amount of oxygen is released. Within the confined space of the battery pack, due to the relatively low oxygen concentration, this mixed gas is usually difficult to spontaneously combust. However, when these high-temperature, high-pressure gases are ejected through the pressure relief valve, they quickly mix with the high-concentration external air to form a flammable mixture. When this mixture encounters an ignition source such as an electric spark or arc generated by a battery short circuit, it can easily ignite a violent, eruptive open flame or even a deflagration at the pressure relief valve outlet. Currently, the industry lacks effective technical solutions to extinguish or suppress such open flames at the pressure relief valve outlet in a short time. Summary of the Invention

[0003] The purpose of this application is to provide a lithium battery deflagration suppression device and a lithium battery pack, which aims to improve the problem that the pressure relief valve of the lithium battery pack is prone to ejecting open flames when thermal runaway is vented, and there is a lack of effective suppression methods.

[0004] To achieve this objective, this application provides a lithium battery deflagration suppression device, which is built into a lithium battery pack and tightly connected to a pressure relief valve installed on the surface of the lithium battery pack; the lithium battery deflagration suppression device includes a device base and a device housing, wherein,

[0005] The device base is provided corresponding to the inlet side of the pressure relief valve. A first groove is recessed on the surface of the device base away from the pressure relief valve. The first groove is filled with a solid fire extinguishing material layer. The surface of the solid fire extinguishing material layer away from the pressure relief valve is respectively recessed with a gas release hole and a normal pressure gas channel. The gas release hole is connected to the high pressure gas release channel of the pressure relief valve, and the normal pressure gas channel is connected to the normal pressure gas release channel of the pressure relief valve. The solid fire extinguishing material layer is configured to release inert gas under high temperature and high pressure.

[0006] The device housing surrounds the device base, and the device housing and the surface of the solid fire extinguishing material layer away from the pressure relief valve are spaced apart to form a sandwich gas flow channel. The surface of the device housing is also provided with a gas inlet that communicates with the sandwich gas flow channel.

[0007] Optionally, in some embodiments of this application, the venting hole extends through the solid fire extinguishing material layer along the depth direction of the first tank, and a first through hole is correspondingly formed at the bottom of the first tank to connect the venting hole with the high-pressure gas venting channel; and / or,

[0008] The atmospheric pressure gas channel is provided to penetrate the solid fire extinguishing material layer along the depth direction of the first tank, and a second through hole is correspondingly opened at the bottom of the first tank to connect the atmospheric pressure gas channel and the atmospheric pressure gas venting channel.

[0009] Optionally, in some embodiments of this application, the surface of the solid fire extinguishing material layer away from the pressure relief valve is further recessed with a gas release blind hole.

[0010] Optionally, in some embodiments of this application, the gas release through holes and / or the gas release blind holes are provided in multiples and are distributed in an array or spiral on the solid fire extinguishing material layer.

[0011] Optionally, in some embodiments of this application, the gas release blind hole extends along the depth direction of the first groove, and the depth of the gas release blind hole is 1 / 5 to 4 / 5 of the thickness of the solid fire extinguishing material layer, and the diameter of the gas release blind hole gradually decreases from the opening of the gas release blind hole to the bottom of the hole.

[0012] Optionally, in some embodiments of this application, the device housing has a second groove recessed on one side surface facing the device base, and the inner diameter of the second groove is greater than or equal to the outer diameter of the device base, so that the second groove can surround and cover the device base.

[0013] The depth of the second tank is greater than the thickness of the device base, so that the interlayer gas flow channel is formed between the bottom of the second tank and the side surface of the solid fire extinguishing material layer away from the pressure relief valve.

[0014] Optionally, in some embodiments of this application, the bottom of the second tank is further covered with a fire extinguishing material plate, wherein the fire extinguishing material plate is a thermal aerosol generator plate or a porous ceramic plate impregnated with perfluorohexanone; and / or,

[0015] A sealing ring is provided between the outer peripheral wall of the device base and the groove wall of the second groove to prevent gas from leaking from the lateral gap between the device base and the device housing.

[0016] Optionally, in some embodiments of this application, the solid fire extinguishing material layer is a perfluorohexanone microcapsule compressed body or a modified sodium salt fire extinguishing material compressed body, and the porosity of the solid fire extinguishing material layer is 15%-35%.

[0017] Optionally, in some embodiments of this application, at least one support protrusion is provided between the device housing and the solid fire extinguishing material layer, the support protrusion being configured to maintain a constant gap in the interlayer gas flow channel; and / or,

[0018] A one-way breathable membrane is provided at the gas inlet of the device housing. This one-way breathable membrane is configured to allow external gas to enter the interlayer gas flow channel while preventing internal gas from escaping back through the interlayer gas flow channel; and / or,

[0019] The inner wall of the venting orifice is coated with a thermosensitive triggering layer, which is configured to decompose and cause local rupture of the solid fire extinguishing material layer when the temperature exceeds a threshold.

[0020] In addition, to achieve this purpose, this application embodiment also provides a lithium battery pack, the lithium battery pack including a lithium battery pack body, a pressure relief valve and the lithium battery deflagration suppression device described in any one of the above.

[0021] The pressure relief valve is installed on the outer surface of the housing of the lithium battery pack body, and the outer surface of the housing of the lithium battery pack body is provided with a clearance opening to avoid the inlet side of the pressure relief valve.

[0022] The lithium battery deflagration suppression device is installed inside the housing of the lithium battery pack body, and the device base of the lithium battery deflagration suppression device is positioned directly opposite the clearance opening, so that the lithium battery deflagration suppression device is tightly connected to the pressure relief valve.

[0023] The lithium battery deflagration suppression device and lithium battery pack provided in this application embodiment, through the above-described structural configuration, when thermal runaway occurs in the cells within the lithium battery pack, the released high-temperature, high-pressure gas first enters the interlayer gas flow channel through the gas inlet of the device casing. At this time, the high-temperature, high-pressure gas directly impacts and heats the surface of the solid fire extinguishing material layer in contact with the interlayer gas flow channel. Due to the synergistic effect of high temperature and high pressure, the solid fire extinguishing material layer begins to release inert gas, forming a preliminary inertized environment within the interlayer flow channel. Simultaneously, the high-temperature, high-pressure gas also flows at high speed towards the venting holes and the normal pressure gas channel. The inner walls of these channels also begin to release a large amount of inert gas due to the effects of high temperature and high pressure. The released inert gas premixes with the high-temperature combustible gas before flowing through the pressure relief valve, reducing the concentration of combustible gas. When the mixed gas is finally ejected through the pressure relief valve, its flammability is greatly reduced due to the presence of sufficient inert gas, thereby effectively suppressing the risk of eruptive open flame combustion or deflagration at the pressure relief valve outlet. As can be seen, this technical solution, by constructing a multi-path inert gas release mechanism, dilutes and inertizes the combustible gas before it is ejected, thereby suppressing the concentration of the combustion-supporting agent in the three elements of combustion from the source. This can effectively improve the problem that the pressure relief valve is prone to causing ejected open flames when it vents and lacks effective suppression methods in the existing technology. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0026] Figure 1 This is a schematic diagram of the assembly state structure of the lithium battery deflagration suppression device according to an embodiment of this application;

[0027] Figure 2 for Figure 1 The diagram shows the disassembled structure of the lithium battery deflagration suppression device.

[0028] Figure 3 for Figure 2 Another structural schematic diagram of the lithium battery deflagration suppression device shown;

[0029] Figure 4 for Figure 1 The diagram shows the structural design of the base of the lithium battery deflagration suppression device.

[0030] Figure 5 for Figure 1 Another structural schematic diagram of the base portion of the lithium battery deflagration suppression device shown.

[0031] Figure label:

[0032] 10. Lithium battery deflagration suppression device; 11. Device base; 111. First tank; 1111. First through hole; 1112. Second through hole; 112. Solid extinguishing material layer; 1121. Gas release through hole; 1122. Atmospheric pressure gas channel; 1123. Gas release blind hole; 12. Device shell; 121. Gas inlet; 122. Second tank; 123. Extinguishing material plate; 131. First screw; 132. First nut post; 133. Second screw; 134. Second nut post; 135. Outer nut; 20. Pressure relief valve; 21. High-pressure gas venting channel; 22. Atmospheric pressure gas venting channel; 30. Shell. Detailed Implementation

[0033] To make the inventive objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] In the description of this application, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component centrally located at the same time.

[0035] The technical solution of this application will be further described below with reference to the accompanying drawings and specific embodiments.

[0036] Please see Figures 1 to 5As shown, in one embodiment, this application provides a lithium battery deflagration suppression device 10, which is built into a lithium battery pack and tightly connected to a pressure relief valve 20 installed on the surface of the lithium battery pack. Specifically, the lithium battery deflagration suppression device 10 may include a device base 11 and a device housing 12. The device base 11 is disposed corresponding to the inlet side of the pressure relief valve 20. A first groove 111 is recessed on the side of the device base 11 away from the pressure relief valve 20. The first groove 111 is filled with a solid fire extinguishing material layer 112. A gas release hole 1121 and a normal pressure gas channel 1122 are respectively recessed on the side of the solid fire extinguishing material layer 112 away from the pressure relief valve 20. The gas release hole 1121 communicates with the high-pressure gas release channel 21 of the pressure relief valve 20, and the normal pressure gas channel 1122 communicates with the normal pressure gas release channel 22 of the pressure relief valve 20. The solid fire extinguishing material layer 112 is configured to release inert gas under high temperature and high pressure. The device housing 12 surrounds the device base 11, and the device housing 12 and the surface of the solid fire extinguishing material layer 112 away from the pressure relief valve 20 are spaced apart to form a sandwich gas flow channel (not shown in the figure). The surface of the device housing 12 is also provided with a gas inlet 121 that communicates with the sandwich gas flow channel.

[0037] It should be noted that the lithium battery deflagration suppression device 10 of this application embodiment is mainly used in lithium battery packs in electric vehicles, energy storage power stations, electronic devices, etc., to actively suppress combustion or deflagration of the ejected gas at the valve port when the battery cell experiences thermal runaway and the pressure relief valve 20 opens to vent, thereby improving the overall safety of the battery pack. The solid fire extinguishing material layer 112 mentioned above mainly refers to a solid material layer that can decompose and release inert gases (such as nitrogen, carbon dioxide, etc.) after being heated, such as metal carbonates, metal hydroxides, or flame retardant composite materials. The gas release hole 1121 mentioned above mainly refers to a through-hole structure for the gas released by the solid fire extinguishing material layer 112 under high temperature and high pressure to be discharged outward. It is connected to the high-pressure gas discharge channel 21 of the pressure relief valve 20 to guide the inert gas to the vicinity of the valve port. The aforementioned atmospheric pressure gas channel 1122 mainly refers to the channel structure used to balance the internal and external gas pressure of the device and prevent gas accumulation from causing abnormal expansion. It is connected to the atmospheric pressure gas discharge channel 22 of the pressure relief valve 20 to ensure that the gas can flow smoothly in a non-thermal runaway state.

[0038] Preferably, the gas inlet 121 mentioned above is configured as multiple air inlets evenly distributed around the outer casing 12 of the device, so that when the battery pack experiences thermal runaway and the pressure relief valve 20 opens, the external high-temperature and high-pressure gas can enter the interlayer gas flow channel evenly from all sides, causing the surface of the solid fire extinguishing material layer 112 to be heated evenly, accelerating the release and diffusion of inert gas, thereby forming a continuous and stable inert gas barrier around the valve port, improving the suppression effect and response speed of deflagration flames.

[0039] Furthermore, the aforementioned device base 11 and device housing 12 are not limited to the circular structure shown in the figure. Specifically, they can be flexibly set as elliptical, square, racetrack-shaped or other irregular structures according to the internal space layout of the lithium battery pack and the actual shape of the pressure relief valve 20, so as to achieve compact installation in a limited space and ensure the precise docking of the vent hole 1121, the atmospheric pressure gas channel 1122 and the corresponding flow channel of the pressure relief valve 20, thereby taking into account both structural adaptability and the reliability of the deflagration suppression function.

[0040] Thus, the lithium battery deflagration suppression device 10 provided in this embodiment, through the above-described structural configuration, allows the released high-temperature, high-pressure gas to first enter the interlayer gas flow channel through the gas inlet 121 of the device housing 12 when thermal runaway occurs within the lithium battery pack cells. At this time, the high-temperature, high-pressure gas directly impacts and heats the surface of the solid fire extinguishing material layer 112 in contact with the interlayer gas flow channel. Due to the synergistic effect of high temperature and high pressure, the solid fire extinguishing material layer 112 begins to release inert gas, forming a preliminary inertized environment within the interlayer flow channel. Simultaneously, the high-temperature, high-pressure gas also flows at high speed towards the release hole 1121 and the atmospheric pressure gas channel 1122. The inner walls of these channels also begin to release large amounts of inert gas due to the effects of high temperature and high pressure. The released inert gas premixes with the high-temperature combustible gas before flowing through the pressure relief valve 20, reducing the concentration of the combustible gas. When the mixed gas is finally ejected through the pressure relief valve 20, its flammability is greatly reduced due to the presence of sufficient inert gas, thus effectively suppressing the risk of eruptive open flame combustion or deflagration at the outlet of the pressure relief valve 20. Therefore, this lithium battery deflagration suppression device 10, by constructing a dual inert gas release path of a sandwiched flow channel and a through-hole channel, utilizes the thermal energy and pressure of the thermally runaway gas itself as a triggering energy source. Without the need for additional sensors or actuators, it can dilute and inertize the flammable gas before it is ejected, significantly reducing the risk of combustion and explosion at the outlet of the pressure relief valve 20. It has the advantages of compact structure, rapid response, and high reliability.

[0041] In some examples, such as Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the venting hole 1121 extends through the solid fire extinguishing material layer 112 along the depth direction of the first tank 111, and a corresponding first through hole 1111 is provided at the bottom of the first tank 111 to connect the venting hole 1121 with the high-pressure gas discharge channel 21. This ensures that the inert gas released from the inner wall of the venting hole 1121 under high temperature and pressure can directly and efficiently enter the high-pressure gas discharge channel 21 of the pressure relief valve 20, premixing with the high-temperature combustible gas flowing through it. This reduces the concentration of combustible components before the gas exits the valve, improving the reliability of suppressing deflagration.

[0042] It should be noted that the vent 1121 in this example is a through hole, and its entire inner wall participates in the release of inert gas to increase the effective release area. In this example, the first through hole 1111 is opened at the bottom of the first groove 111, and its diameter matches the diameter of the corresponding vent 1121 to ensure smooth airflow and avoid turbulence or local pressure loss due to abrupt changes in cross-section. This ensures that the high-temperature combustible gas and the released inert gas can be smoothly and fully mixed before entering the pressure relief valve 20.

[0043] In some examples, such as Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the atmospheric pressure gas channel 1122 extends through the solid fire extinguishing material layer 112 along the depth direction of the first tank 111, and a second through hole 1112 is correspondingly opened at the bottom of the first tank 111 to connect the atmospheric pressure gas channel 1122 and the atmospheric pressure gas venting channel 22. This ensures that under normal operating conditions, trace amounts of gas generated inside the lithium battery pack due to temperature changes or cell breathing effects can be smoothly discharged through the atmospheric pressure gas channel 1122 and the second through hole 1112 via the atmospheric pressure gas venting channel 22 of the pressure relief valve 20, thereby maintaining the pressure balance inside and outside the battery pack and preventing the casing 30 from bulging or the seal from failing due to lack of venting. Simultaneously, this channel can also serve as an auxiliary release path for inert gas in the event of thermal runaway, further enhancing the suppression effect.

[0044] It should be noted that the cross-sectional area of ​​the atmospheric pressure gas channel 1122 in this example is usually smaller than the cross-sectional area of ​​the venting hole 1121, so as to limit the large amount of high-temperature and high-pressure gas passing through the channel during thermal runaway while ensuring the daily ventilation function. This guides most of the high-pressure gas to flow preferentially through the venting hole 1121, ensuring that the solid fire extinguishing material layer 112 is fully heated at the inner wall of the venting hole 1121 and releases inert gas.

[0045] In some examples, such as Figure 2 and Figure 5As shown, the surface of the solid fire extinguishing material layer 112 away from the pressure relief valve 20 is also recessed with gas release blind holes 1123. This significantly increases the contact area between the solid fire extinguishing material layer 112 and the high-temperature, high-pressure gas without penetrating the solid fire extinguishing material layer 112. When the thermal runaway gas (i.e., high-temperature, high-pressure gas) enters the interlayer gas flow channel, some of the gas rapidly flows into these gas release blind holes 1123, heating the solid fire extinguishing material layer 112 from multiple directions along the hole walls, causing the material with a larger surface area to simultaneously decompose and release inert gas. Because the gas release blind holes 1123 are bottom-closed structures, the airflow cannot penetrate through the holes after impact, causing the inert gas released from the inner wall of the gas release blind holes 1123 to accumulate briefly before flowing back towards the interlayer gas flow channel, where it mixes thoroughly with the high-temperature thermal runaway gas flowing through it, and then flows together towards the gas release through hole 1121 and the atmospheric pressure gas channel 1122. This process not only prolongs the mixing time of inert gas and combustible gas, but also significantly increases the release rate of inert gas per unit time by utilizing the multi-directional heating effect of the inner wall of the blind hole, thereby generating a higher concentration of inert gas in a short time and effectively improving the suppression response speed and suppression intensity of deflagration.

[0046] It should be noted that the gas release blind hole 1123 in this example is a hole with a closed bottom, which is not connected to the flow channel of the pressure relief valve 20. This structure increases the heat exchange area and avoids gas short-circuiting, ensuring that the high-temperature gas stays in the gas release blind hole 1123 for a slightly longer time, which is conducive to the transfer of heat to the interior of the solid fire extinguishing material layer 112, thereby more fully stimulating the release of inert gas, while preventing unsuppressed high-concentration combustible gas from bypassing the fire extinguishing material and escaping directly.

[0047] In some examples, such as Figure 2 and Figure 5 As shown, multiple release orifices 1121 and / or blind release orifices 1123 are provided, and are arranged in an array or spiral pattern on the solid extinguishing material layer 112. This allows for a more uniform distribution of high-temperature, high-pressure gas as it flows across the surface of the solid extinguishing material layer 112, avoiding uneven material release due to localized airflow concentration. The array or spiral distribution helps to form a regular airflow path, ensuring that each orifice can independently and fully contact the high-temperature gas, thereby making the release of inert gas in the entire solid extinguishing material layer 112 more balanced and efficient, ultimately resulting in a more thorough mixing with the combustible gas and improving the reliability of deflagration suppression.

[0048] It should be noted that the array distribution in this example refers to the channels being arranged in a row and column alignment manner, which is simple to process and uniformly distributed. The spiral distribution refers to the channels being arranged along a spiral line from the center outwards, which is beneficial for guiding the airflow in a vortex shape and prolonging the contact time between the gas and the orifice wall. The specific choice can be made according to the actual flow channel design and processing technology. Furthermore, when multiple venting holes 1121 are set, their correspondence with the high-pressure gas venting channel 21 of the pressure relief valve 20 can be flexibly configured according to actual design requirements: a single venting hole 1121 can correspond to and connect to one high-pressure gas venting channel 21 (e.g., ...). Figure 2 As shown), the diameter of the venting orifice 1121 is approximately equal to the diameter of the high-pressure gas venting channel 21 to ensure the smooth flow of gas in a single path; alternatively, multiple venting orifices 1121 can be connected to a single high-pressure gas venting channel 21 (e.g., Figure 5 As shown in the figure, at this time, the diameter of each individual gas release hole 1121 is smaller than the diameter of the high-pressure gas venting channel 21, so as to increase the contact area between the inert gas and the combustible gas by the diversion method and improve the mixing uniformity.

[0049] In some examples, such as Figure 2 and Figure 5 As shown, the venting blind hole 1123 extends along the depth direction of the first groove 111, and the depth of the venting blind hole 1123 is 1 / 5 to 4 / 5 of the thickness of the solid fire extinguishing material layer 112. The diameter of the venting blind hole 1123 gradually decreases from the opening of the venting blind hole 1123 to the bottom of the hole. In this way, the tapered and tapered hole design can accommodate more high-temperature gas at the opening of the blind hole, and the decreasing hole diameter as the depth increases can produce a certain compression and acceleration effect on the incoming gas, enhance the heat exchange efficiency between the gas and the hole wall, and promote the decomposition and gas release of the material at a deeper depth. By controlling the depth of the venting blind hole 1123 to be between 1 / 5 and 4 / 5 of the material thickness, sufficient venting surface area can be ensured, while sufficient bottom material strength can be maintained to prevent the material from breaking and peeling off at high temperatures and to maintain structural integrity.

[0050] It should be noted that the depth of the venting blind hole 1123 in this example can be optimized based on the total thickness of the solid extinguishing material layer 112 and the thermal conductivity of the material. When its depth is less than 1 / 5, the increase in surface area is limited and the effect is not obvious; while the current depth is greater than 4 / 5, the bottom is too thin and easily cracks and falls off under thermal shock. The conical hole in this example can be achieved by molding or precision drilling.

[0051] In some examples, such as Figure 2 and Figure 5As shown, a second groove 122 is recessed on the surface of the device housing 12 facing the device base 11. The inner diameter of the second groove 122 is greater than or equal to the outer diameter of the device base 11, so that the second groove 122 can surround and cover the device base 11. The groove depth of the second groove 122 is greater than the thickness of the device base 11, so that a sandwich gas flow channel is formed between the bottom of the second groove 122 and the surface of the solid fire extinguishing material layer 112 away from the pressure relief valve 20. In this way, through the nested groove structure, a sandwich gas flow channel can be compactly formed in a limited space without the need for additional gaskets or supports. The device base 11 is completely accommodated inside the second groove 122 of the device housing 12, which not only serves to position and fix the device, but also ensures that the high-temperature and high-pressure gas entering from the gas inlet 121 can more fully contact the solid fire extinguishing material layer 112 in the sandwich gas flow channel, ensuring sufficient and uniform heating.

[0052] It should be noted that the fitting clearance between the inner diameter of the second groove 122 and the outer diameter of the device base 11 should be controlled within a reasonable range, so as to facilitate assembly and prevent excessive airflow from the side. Typically, this single-sided clearance is 2mm to 10mm, and a sealing ring can be added if necessary to achieve better airtightness.

[0053] In some examples, such as Figure 3 As shown, the bottom of the second tank 122 is also covered with a fire extinguishing material plate 123, which is a thermal aerosol generator plate or a porous ceramic plate impregnated with perfluorohexanone. Thus, when high-temperature, high-pressure gas enters the interlayer gas flow channel, it directly impacts and heats the fire extinguishing material plate 123, causing it to decompose and release additional fire extinguishing substances (such as aerosol particles or perfluorohexanone vapor). These fire extinguishing substances work synergistically with the inert gas released from the solid fire extinguishing material layer 112, reducing the concentration of oxygen and combustible gases through physical dilution and significantly enhancing the chemical suppression capability against deflagration flames by chemically interrupting the combustion chain reaction. This is particularly suitable for suppressing extreme thermal runaway scenarios where open flames have already appeared.

[0054] It should be noted that the thermal aerosol generator plate in this example is typically made by pressing strontium nitrate and potassium nitrate as oxidants, phenolic resin as fuel, and adding a coolant. Upon heating, it undergoes a redox reaction to generate a large number of aerosol particles. The perfluorohexanone-impregnated porous ceramic plate in this example adsorbs liquid perfluorohexanone into a highly porous ceramic matrix. Upon heating, the perfluorohexanone rapidly vaporizes and releases, exhibiting high latent heat of vaporization and chemical inhibition, resulting in high fire extinguishing efficiency. For those skilled in the art, this fire extinguishing material plate 123 can also be replaced with other material plates capable of releasing inert gases under high temperature and pressure, such as sodium bicarbonate pressed plates or metal hydroxide composite plates, to achieve inert gas release while also considering cost control or environmental adaptability requirements. The specific material selection does not constitute a limitation on the scope of protection of this application.

[0055] In some examples, such as Figure 1 and Figure 3 As shown, a sealing ring is provided between the outer peripheral wall of the device base 11 and the groove wall of the second groove 122 to prevent gas leakage from the lateral gap between the device base 11 and the device housing 12. This forces the high-temperature, high-pressure gas to pass only through the pre-designed interlayer gas flow channel, the release hole 1121, and the atmospheric pressure gas channel 1122, preventing gas from bypassing and escaping through the assembly gap between the device base 11 and the device housing 12. This ensures that all high-temperature gas flows through the surface and inner walls of the pores of the solid extinguishing material layer 112, maximizing the use of the thermal energy of the thermally runaway gas to trigger the release of the inert gas, while preventing high-concentration combustible gas that has not fully contacted the extinguishing material from directly reaching the pressure relief valve 20, thus improving the reliability and effectiveness of the suppression system.

[0056] It should be noted that the sealing ring can be made of high-temperature resistant silicone rubber or fluororubber and installed in the pre-set annular groove on the outer peripheral wall of the device base 11. When the device housing 12 is assembled with the device base 11, the sealing ring is pressed between the two to form a reliable gas seal.

[0057] In some examples, such as Figure 2 and Figure 5As shown, the solid fire extinguishing material layer 112 is a perfluorohexanone microcapsule compressed body or a modified sodium salt fire extinguishing material compressed body, with a porosity of 15%-35%. When heated, the perfluorohexanone microcapsule compressed body ruptures its microcapsule wall material, releasing liquid perfluorohexanone, which rapidly vaporizes and absorbs a large amount of heat. Simultaneously, the free radical scavengers generated during decomposition interrupt the combustion chain reaction. The modified sodium salt fire extinguishing material (such as a mixture of NaHCO3 or KHCO3 and a binder) compressed body decomposes upon heating, releasing CO2 and water vapor, thus diluting and cooling the material. Controlling the porosity between 15% and 35% ensures sufficient mechanical strength and structural integrity, preventing breakage under vibration or airflow impact, while also providing interconnected microporous channels to facilitate the penetration of high-temperature gases into the material, promoting heat transfer and gas release, and providing pathways for the escape of gaseous products.

[0058] It should be noted that the porosity of the solid fire extinguishing material layer 112 is limited to 15%-35% in this example because a porosity that is too low (<15%) will result in poor gas permeability, making it impossible to effectively heat the interior of the material and leading to low gas release efficiency. Conversely, a porosity that is too high (>35%) will result in insufficient material strength, making it prone to pulverization and peeling under the impact of high-speed airflow during thermal runaway, potentially blocking airflow channels. Specifically, this porosity can be achieved by adjusting the pressing pressure or adding a pore-forming agent. Furthermore, the perfluorohexanone microcapsule press in this example is mainly formed from a material based on perfluorohexanone fire extinguishing microcapsules. Specifically, the perfluorohexanone fire extinguishing microcapsules can be those described in the applicant's previously filed Chinese patent CN 118649393 A. This patent application discloses a perfluorohexanone (PFH) fire extinguishing microcapsule, comprising a capsule wall and a capsule core. The capsule core contains liquid PPH, and the capsule wall comprises an inner shell layer and an outer shell layer stacked together. The inner shell layer comprises a gelatin / montmorillonite / sodium polyphosphate composite, and the outer shell layer comprises polyisocyanate / phenolic resin. This multi-layered encapsulation structure exhibits excellent encapsulation properties for PPH, maintaining structural integrity under high-temperature conditions and preventing premature leakage of the extinguishing agent in a non-triggered state. When the ambient temperature reaches the trigger threshold (typically 110℃-130℃), the microcapsule wall ruptures, releasing PPH to extinguish the fire. This microcapsule can be prepared using a composite agglomeration method or microfluidic technology, with a particle size controllable between 20μm and 600μm and an encapsulation efficiency exceeding 80%. It also possesses good storage stability and thermal trigger response characteristics. Those skilled in the art can select the above-mentioned type of PPH fire extinguishing microcapsule and combine it with an appropriate adhesive for compression according to actual pressing process requirements to obtain a solid fire extinguishing material layer 112 with a porosity of 15%-35%.

[0059] In some examples, such as Figure 2 and Figure 3As shown, at least one support protrusion is provided between the device housing 12 and the solid extinguishing material layer 112. The support protrusion is configured to maintain a constant gap in the interlayer gas flow channel. This prevents uneven deformation or partial closure of the gap in the interlayer gas flow channel between the solid extinguishing material layer 112 and the device housing 12 when subjected to vibration, impact, or high-temperature, high-pressure airflow. The support protrusion, as a rigid support point, ensures that the cross-sectional area of ​​the entire interlayer gas flow channel remains stable, thereby guaranteeing the uniformity of gas flow and uniform heating of the surface of the solid extinguishing material layer 112. This avoids abnormal increases in airflow velocity or uneven pressure distribution due to local narrowing of the interlayer gas flow channel, which could affect the stable release of the inert gas.

[0060] It should be noted that the support protrusion in this example can be set at the bottom of the second groove 122 of the device housing 12, or on the surface of the solid extinguishing material layer 112, or both. The height of the protrusion is slightly smaller than the design gap of the interlayer gas flow channel, usually 0.8 to 0.95 times the gap value, to avoid excessive compression of the material. Preferably, since the device housing 12 and the device base 11 are mainly fastened together by two first screws 131 (generally protruding at the bottom of the second groove 122) and two first nut posts 132 (generally protruding at the bottom of the first groove 111), these two fasteners themselves have a certain supporting function. Therefore, in actual design, a portion of the first screw 131 or a portion of the first nut post 132 can be directly used as the aforementioned support protrusion to reduce the setting of additional components. Furthermore, the bottom of the second groove 122 is provided with four second screws 133, and the bottom of the first groove 111 is provided with four second nut posts 134. The lithium battery deflagration suppression device 10 is assembled and fixed inside the lithium battery pack by having each of the second screws 133 pass through the corresponding second nut posts 134 and the housing 30 of the lithium battery pack, and then locked by the corresponding outer nuts 135. It is understood that these second screws 133 and second nut posts 134 can also provide auxiliary support after assembly, further enhancing the stability of the gap structure of the interlayer gas flow channel.

[0061] In some examples, a one-way breathable membrane (not shown) is provided at the gas inlet 121 of the device housing 12. This membrane is configured to allow external gas to enter the interlayer gas channel while preventing internal gas from escaping back through it. Thus, during normal operation of the battery pack, the one-way breathable membrane allows air to enter the interlayer gas channel, maintaining pressure balance and preventing pressure buildup due to sealing. However, when thermal runaway occurs and the internal pressure rises sharply, the one-way breathable membrane automatically closes under the reverse pressure difference, preventing high-temperature flammable gas from being ejected back from the gas inlet 121 into other areas of the battery pack, thus preventing flame spread. Simultaneously, this also forces all high-temperature gases to be discharged only through the pressure relief valve 20, ensuring that all gases are mixed with an inert gas, improving overall safety.

[0062] It should be noted that the one-way breathable membrane in this example can be a microporous polymer film with directional breathability (such as expanded polytetrafluoroethylene ePTFE membrane) or a valve-type silicone structure, which opens for breathability under a small positive pressure difference and quickly seals under a larger reverse pressure difference.

[0063] In some examples, the inner wall of the venting orifice 1121 is coated with a thermosensitive triggering layer (not shown). This layer is configured to decompose and cause localized rupture of the solid extinguishing material layer 112 when the temperature exceeds a threshold. Thus, when the temperature of the thermal runaway gas reaches a set threshold (e.g., 150°C to 200°C), the thermosensitive triggering layer coated on the inner wall of the venting orifice 1121 rapidly decomposes, generating localized high pressure or micro-shock waves, causing microcracks to form on the inner wall surface of the solid extinguishing material layer 112. These microcracks further increase the contact area between the material and the high-temperature gas, exposing unreacted fresh material inside, thereby accelerating the release of inert gas. This allows the lithium battery deflagration suppression device 10 to respond more quickly to high-temperature thermal runaway events, shortening the delay time between gas ejection and inert gas release.

[0064] It should be noted that the thermal trigger layer in this example can be made by mixing organic compounds with low decomposition temperatures (such as azobisisobutyronitrile, benzoyl peroxide, etc.) with a binder, with a coating thickness of 10μm to 100μm. Its decomposition temperature can be customized according to the actual temperature range of lithium battery thermal runaway.

[0065] In one embodiment, such as Figures 1 to 5As shown in the illustration, this application also provides a lithium battery pack, which includes a lithium battery pack body, a pressure relief valve 20, and a lithium battery deflagration suppression device 10 as described above. The pressure relief valve 20 is installed on the outer surface of the housing 30 of the lithium battery pack body, and the outer surface of the housing 30 of the lithium battery pack body has a clearance opening to avoid the inlet side of the pressure relief valve 20. The lithium battery deflagration suppression device 10 is installed on the inner side of the housing 30 of the lithium battery pack body, and the device base 11 of the lithium battery deflagration suppression device 10 is positioned directly opposite the clearance opening, so that the lithium battery deflagration suppression device 10 is tightly connected to the pressure relief valve 20.

[0066] It should be noted that the lithium battery packs in this application embodiment are mainly used in fields with high safety requirements, such as electric passenger vehicles, electric buses, energy storage containers, home energy storage systems, and portable power tools. Its core advantage is that when the battery cell experiences thermal runaway and triggers the pressure relief valve 20 to release gas, it can actively suppress the deflagration phenomenon at the outlet of the pressure relief valve 20, significantly reducing the risk of fire and explosion and improving the safety of personnel and equipment.

[0067] In this way, the lithium battery pack provided in this embodiment integrates a lithium battery deflagration suppression device 10 inside its casing 30 and tightly connects the lithium battery deflagration suppression device 10 to the pressure relief valve 20. This ensures that when the lithium battery pack experiences thermal runaway, the high-temperature, high-pressure combustible gas generated inside must flow through the interlayer gas channel and venting hole 1121 of the lithium battery deflagration suppression device 10 before reaching the pressure relief valve 20. During this process, the heat and pressure of the gas trigger the solid fire extinguishing material layer 112 to release a large amount of inert gas, which is fully premixed with the combustible gas, thereby significantly reducing the concentration of combustible components before the gas exits the valve. Finally, the gas discharged from the pressure relief valve 20 is sufficiently inertized, making it difficult to form a combustible mixture with the outside air at the valve opening. Even if there is an ignition source such as an electric spark, it will not cause violent deflagration, thus greatly improving the overall safety level of the lithium battery pack under thermal runaway conditions and solving the problem that traditional pressure relief valves 20 can only passively vent gas and cannot suppress open flames.

[0068] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A lithium battery deflagration suppression device, characterized in that, The lithium battery deflagration suppression device is built into the lithium battery pack and is tightly connected to a pressure relief valve installed on the surface of the lithium battery pack; the lithium battery deflagration suppression device includes a device base and a device housing, wherein, The device base is positioned corresponding to the inlet side of the pressure relief valve. A first groove is recessed on the surface of the device base away from the pressure relief valve. The first groove is filled with a solid fire extinguishing material layer. The surface of the solid fire extinguishing material layer away from the pressure relief valve is respectively recessed with a gas release through hole, a normal pressure gas channel, and a gas release blind hole. The gas release through hole is connected to the high-pressure gas release channel of the pressure relief valve, and the normal pressure gas channel is connected to the normal pressure gas release channel of the pressure relief valve. The gas release blind hole extends along the groove depth direction of the first groove, and the depth of the gas release blind hole is 1 / 5 to 4 / 5 of the thickness of the solid fire extinguishing material layer. The diameter of the gas release blind hole gradually decreases from the opening of the gas release blind hole to the bottom of the hole. The porosity of the solid fire extinguishing material layer is 15%-35%, and the solid fire extinguishing material layer is designed to release inert gas under high temperature and high pressure. The device housing surrounds the device base, and the device housing and the surface of the solid fire extinguishing material layer away from the pressure relief valve are spaced apart to form a sandwich gas flow channel. The surface of the device housing is also provided with a gas inlet that communicates with the sandwich gas flow channel.

2. The lithium battery deflagration suppression device according to claim 1, characterized in that, The venting hole extends through the solid fire extinguishing material layer along the depth direction of the first tank, and a first through hole is correspondingly formed at the bottom of the first tank to connect the venting hole with the high-pressure gas release channel; and / or, The atmospheric pressure gas channel is provided to penetrate the solid fire extinguishing material layer along the depth direction of the first tank, and a second through hole is correspondingly opened at the bottom of the first tank to connect the atmospheric pressure gas channel and the atmospheric pressure gas venting channel.

3. The lithium battery deflagration suppression device according to claim 1, characterized in that, The gas release through holes and / or the gas release blind holes are configured in multiples and are distributed in an array or spiral on the solid fire extinguishing material layer.

4. The lithium battery deflagration suppression device according to claim 1, characterized in that, The outer surface of the device housing facing the device base has a second groove recessed therein, and the inner diameter of the second groove is greater than or equal to the outer diameter of the device base, so that the second groove can surround and cover the device base. The depth of the second tank is greater than the thickness of the device base, so that the interlayer gas flow channel is formed between the bottom of the second tank and the side surface of the solid fire extinguishing material layer away from the pressure relief valve.

5. The lithium battery deflagration suppression device according to claim 4, characterized in that, The bottom of the second tank is also covered with a fire extinguishing material plate, which is a thermal aerosol generator plate or a porous ceramic plate impregnated with perfluorohexanone; and / or, A sealing ring is provided between the outer peripheral wall of the device base and the groove wall of the second groove to prevent gas from leaking from the lateral gap between the device base and the device housing.

6. The lithium battery deflagration suppression device according to claim 1, characterized in that, The solid fire extinguishing material layer is a perfluorohexanone microcapsule compressed body or a modified sodium salt fire extinguishing material compressed body.

7. The lithium battery deflagration suppression device according to any one of claims 1-6, characterized in that, At least one support protrusion is provided between the outer shell of the device and the solid fire extinguishing material layer, the support protrusion being configured to maintain a constant gap in the interlayer gas flow channel; and / or, A one-way breathable membrane is provided at the gas inlet of the device housing. This one-way breathable membrane is configured to allow external gas to enter the interlayer gas flow channel while preventing internal gas from escaping in the reverse direction from the interlayer gas flow channel; and / or, The inner wall of the venting orifice is coated with a thermosensitive triggering layer, which is configured to decompose and cause local rupture of the solid fire extinguishing material layer when the temperature exceeds a threshold.

8. A lithium battery pack, characterized in that, The lithium battery pack includes a lithium battery pack body, a pressure relief valve, and a lithium battery deflagration suppression device as described in any one of claims 1-7; The pressure relief valve is installed on the outer surface of the housing of the lithium battery pack body, and the outer surface of the housing of the lithium battery pack body is provided with a clearance opening to avoid the inlet side of the pressure relief valve. The lithium battery deflagration suppression device is installed inside the housing of the lithium battery pack body, and the device base of the lithium battery deflagration suppression device is positioned directly opposite the clearance opening, so that the lithium battery deflagration suppression device is tightly connected to the pressure relief valve.

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