Thermal runaway safety protection structure for large capacity battery

Abstract

The application relates to a thermal runaway safety protection structure of a large-capacity battery, which comprises a discharge pipeline, a circulation pipeline, a flame-retardant medium releasing device and a starting device. After the positive and negative electrode contact pieces of the starting device are impacted and contacted by thermal runaway gas in the discharge pipeline, the flame-retardant medium releasing device is started, synchronous triggering is achieved by using the gas pressure in the discharge pipeline, a starting signal is sent to the flame-retardant medium releasing device, the combustible gas of the battery thermal runaway is almost synchronously released, the combustible gas of the battery thermal runaway is mixed, diluted, cooled and flame-retarded in the pipeline, the mixed gas can be reduced below the combustible concentration and safely discharged, and secondary disasters such as explosion and ignition caused by the combustible gas leakage due to the thermal runaway of the battery can be effectively avoided.

Description

Technical Field

[0001] This invention belongs to the field of battery safety technology, specifically relating to a thermal runaway safety protection structure for large-capacity batteries. Technical Background

[0002] Lithium batteries are a new type of battery with high specific energy, high voltage, long service life, no environmental harm, and no memory effect. Traditional lithium batteries generate a lot of heat during operation. Since lithium battery materials have poor thermal conductivity, the heat inside the lithium battery will accumulate rapidly, causing the lithium battery temperature to become too high. This may further lead to a decrease in lithium battery performance or thermal runaway, and in severe cases, it may cause dangerous consequences such as combustion or explosion.

[0003] Lithium-ion batteries employ safety structures that improve heat dissipation and cool the battery, including features like pressure relief vents and air collection chambers. Improving heat dissipation and cooling are preventative safety measures, while pressure relief vents and air collection chambers are remedial measures in the event of actual thermal runaway. However, if a lithium-ion battery experiences thermal runaway and the pressure relief vent opens, the electrolyte, positive and negative electrode materials, and other internal components will be ejected into the environment along with the high internal temperature. These substances, especially the electrolyte, are highly flammable, and their temperature upon ejection exceeds their auto-ignition point. They will immediately ignite in the air, setting off nearby materials and causing secondary damage. Fires caused by thermal runaway in lithium-ion batteries are generally considered difficult to extinguish, requiring the exhaustion of internal combustibles. Therefore, the primary safety concern in the event of thermal runaway is minimizing the extent of secondary damage.

[0004] Unlike ordinary fires, the process of battery thermal runaway continuously generates flammable gases and produces a large amount of heat. If the thermal aerosol extinguishing agent is activated at the same time as the battery thermal runaway, the gases continuously generated during the battery thermal runaway will continuously squeeze the thermal aerosol extinguishing agent out of the battery compartment. Therefore, designing the amount of thermal aerosol extinguishing device based solely on the size of the battery compartment is obviously insufficient to meet the extinguishing needs of battery fires.

[0005] For example, patent CN202997005U discloses a battery safety protection device, which includes a battery box and a storage container containing a cooling agent. The battery box is used to hold one or more batteries. The battery box is connected to the storage container through a connecting pipe. The part of the connecting pipe located inside the battery box is provided with one or more activation devices. By placing the battery or battery pack in a battery box and then connecting the battery box to a storage container containing a cooling agent through a connecting pipe, the activation device will open when a battery short-circuits and releases heat, causing the temperature inside the battery box to rise. The cooling agent in the storage container will then enter the battery box to lower the temperature inside the battery box. However, this method can only cool down the battery and prevent thermal runaway. But when the heat of the battery exceeds its cooling capacity, thermal runaway and explosion may still occur.

[0006] For example, patent CN112316332 A proposes an early warning method for lithium-ion battery cabinets. The early warning features include temperature, characteristic gas, smoke, and flame. The fire extinguishing system consists of nozzles and a fire extinguishing agent storage tank located around the lithium battery 1. The three-level early warning includes: 1. Abnormal lithium battery temperature but not reaching a preset temperature threshold; 2. Lithium battery temperature exceeding the preset threshold and detection of characteristic gas, smoke, and flame signals; 3. Lithium battery temperature exceeding the preset threshold and continuous increase in characteristic gas and smoke concentrations exceeding the preset threshold. The fire extinguishing measure is spraying different doses of fire extinguishing agent. This patent monitors the external temperature information of the battery, but a significant temperature difference exists between the inside and outside of the battery, causing it to fail to accurately reflect the battery's thermal runaway state. Patent CN108008083 A proposes an automatic alarm for thermal runaway of lithium-ion battery packs based on gas monitoring, consisting of a collection device, a gas monitoring device, a control device, and an alarm device. The collection device includes a collection cover installed above the positive terminal of the battery, a flame arrester, and a gas pump; the monitoring device includes a gas collection box, a gas sensor, and DuPont wires. The warning method involves a gas collection hood collecting the gas escaping from the lithium-ion battery 1, which is then transmitted to a gas sensor via a gas pump. The concentration thresholds for both CO and H2 are set at 120 ppm. An alarm signal is issued when the concentration of one of the gases reaches the threshold. However, the H2 concentration threshold setting in this patent is unreasonable, and the monitoring is based on only a single gas, resulting in poor reliability and a high risk of false alarms. Furthermore, neither of the two patents can effectively prevent the explosion caused by the mixed gas generated during battery thermal runaway.

[0007] CN212700167U discloses a passive fire extinguishing device and a battery pack. The battery pack has a fire chamber containing a gaseous fire extinguishing agent. The fire extinguishing agent and the driving gas are sealed together to form a pressurized fire extinguishing agent. When the battery experiences thermal runaway, the port of the fire extinguishing gas opens, and the pressure of the driving gas drives the fire extinguishing agent to extinguish the fire in the battery. When extinguishing fire in this way, because the temperature during battery thermal runaway is high and the time is long, it may cause the pressurized fire extinguishing agent to explode, or it may cause the fire extinguishing agent to be released prematurely and fail to achieve the purpose of extinguishing the fire.

[0008] Therefore, when a battery experiences thermal runaway, the key to whether the fire suppression system can effectively suppress a battery fire lies in its ability to systematically spray extinguishing agents to mix with the flammable gases produced during battery thermal runaway, ensuring the mixture reaches concentrations below flammable levels or outside the explosion limits. Because battery thermal runaway typically lasts for several minutes, uncontrolled release of the extinguishing agent could prematurely deplete it, potentially leading to an explosion or ignition of other objects during the subsequent runaway. However, current technologies do not address this issue effectively, failing to resolve ongoing concerns such as whether the fire can be truly extinguished and whether it will cause secondary damage or trigger a secondary fire. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a thermal runaway safety protection structure for large-capacity batteries. The structure utilizes the impact force of the combustible gas released during battery thermal runaway to simultaneously activate a flame-retardant medium release device, discharging the flame-retardant medium to mix and dilute the combustible gas, achieving dilution, cooling, and flame retardancy. After being turbulent, the gas enters a gas circulation pipeline for thorough mixing. When the pressure of the mixed gas exceeds the set value of the gas pressure valve, it is safely discharged through a safety valve on the circulation pipeline. This safety protection structure effectively prevents secondary disasters such as explosions and fires caused by combustible gas leakage due to battery thermal runaway.

[0010] The technical solution adopted in this application is as follows:

[0011] A thermal runaway safety protection structure for a high-capacity battery, comprising:

[0012] The venting pipeline is connected to the pressure relief port of the battery cell to release thermal runaway flammable gases;

[0013] A circulation pipeline is connected to the outlet of the aforementioned venting pipeline to dilute the mixed thermal runaway combustible gas;

[0014] A flame-retardant medium release device, connected to a discharge pipeline, is used to release a flame-retardant medium that can dilute thermally runaway flammable gases;

[0015] The starting device is triggered synchronously by the gas pressure in the venting pipeline and sends a start signal to the flame-retardant medium release device.

[0016] Further specified, the circulation pipeline is a ring pipeline, with a mixed gas inlet and a mixed gas outlet respectively provided on opposite sides of the ring pipeline, so that the mixed thermal runaway combustible gas circulates and extends the flow in the ring pipeline.

[0017] Further specified, a second gas check valve is provided at the inlet of the mixed gas, which is connected to the venting pipeline; a safety valve is provided at the outlet of the mixed gas.

[0018] Further defined, the venting pipeline includes a first branch, a second branch, and a third branch. The first branch and the third branch form a straight-through structure. The first branch is connected to the pressure relief port of the battery. The third branch is connected to the mixed gas inlet of the circulation pipeline. The outlet end of the second branch is connected to the connection point of the first branch and the second branch. The second branch is also connected to the flame-retardant medium release device.

[0019] Furthermore, the inner cavity of the third branch is provided with multiple spoilers, and the multiple spoilers are staggered.

[0020] Furthermore, the spoiler has a semi-circular, fan-shaped, or crescent-shaped structure.

[0021] Further specifying, the starting device includes a negative electrode contact and a positive electrode contact, which are disposed opposite to each other in the first branch of the discharge pipeline, and are electrically connected to the flame-retardant medium release device.

[0022] Furthermore, the starting device also includes a power source, the negative contact is connected to the negative terminal of the power source, and the positive contact is connected to the positive terminal of the power source through the starting switch of the flame-retardant medium release device or a solenoid valve.

[0023] Furthermore, the negative electrode contact piece and the positive electrode contact piece are respectively insulated and fixed to the first branch of the discharge pipeline through an insulating layer.

[0024] Furthermore, the spacing between the negative electrode contact piece and the positive electrode contact piece is sufficient to allow them to contact due to the pressure impact of thermal runaway combustible gas.

[0025] Furthermore, the negative electrode contact and the positive electrode contact are made of magnetic metal material.

[0026] Furthermore, the flame-retardant medium release device is equipped with a flame-retardant medium that can dilute thermally runaway flammable gases.

[0027] Further specifying, the flame retardant medium is one or more of heptafluoropropane, nitrogen, perfluoropropane, perfluorobutane, perfluorohexane, perfluoroacetone, or perfluorohexanone.

[0028] Furthermore, the inner cavity of the first branch is provided with a filter material, which is rock wool or glass fiber wool.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1) The safety protection structure of this application has a simple activation trigger component and does not require human intervention during operation. By using the positive and negative contact plates set in the discharge pipeline, the circuit can be quickly connected to start the flame retardant medium release device under the impact of the thermal runaway combustible gas of the battery, so that the flame retardant medium and the thermal runaway combustible gas of the battery can be released synchronously, thereby achieving the purpose of synchronous release and mixing of thermal runaway combustible gas and flame retardant medium.

[0031] 2) This application provides a turbulence structure at the outlet end of the venting pipeline so that the thermally runaway combustible gas and the flame-retardant medium are mixed and then turbulent by the turbulence plate, extending the flow path so that the two are initially mixed at the outlet end of the venting pipeline.

[0032] 3) The mixed gas circulation pipeline set in this application is conducive to further and more thorough mixing of the mixed gas during the circulation flow in the pipeline. The safety valve on the mixed pipeline can be opened intermittently. When the pipeline pressure reaches the valve opening pressure, the safety valve opens. When the pressure in the pipeline drops, the safety valve closes. The mixed gas in the pipeline is fully mixed under pressure limiting conditions.

[0033] 4) This application can dilute, cool, and flame retard flammable gases caused by battery thermal runaway, greatly reducing their flammability so that they can be safely discharged or collected. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A schematic diagram of the thermal runaway safety protection structure for the first type of large-capacity battery.

[0036] Figure 2 This is a schematic diagram of the thermal runaway safety protection structure for the second type of large-capacity battery.

[0037] Figure 3 Schematic diagram of venting pipeline 2;

[0038] Figure 4 This is a cross-sectional view of the venting pipeline 2;

[0039] Figure 5 Schematic diagram of circulation pipeline 3;

[0040] In the diagram, 1-battery; 2-discharge pipeline; 21-first branch; 22-second branch; 23-connection interface; 24-third branch; 25-baffle; 3-circulation pipeline; 31-mixed gas inlet; 32-mixed gas outlet; 33-ring pipeline; 34-pipe connector; 4-flame retardant medium release device; 5-power supply; 6-first gas check valve; 7-second gas check valve; 8-safety valve; 9-negative contact plate; 10-positive contact plate; 11-solenoid valve. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description. It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not imply the presence or addition of one or more other elements or combinations thereof.

[0042] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] This application is mainly designed as a safety protection structure for the thermal runaway problem of a large-capacity lithium battery 1, but it is not limited to use in lithium battery 1.

[0044] See Figure 1 The thermal runaway safety protection structure for high-capacity batteries in this application includes:

[0045] The venting pipe 2 is connected to the pressure relief port of battery unit 1 to promptly discharge the thermal runaway flammable gas when battery unit 1 experiences thermal runaway.

[0046] The flame retardant medium release device 4 is connected to the discharge pipeline 2 to release a flame retardant medium that can dilute thermally runaway combustible gas to the output section of the discharge pipeline 2.

[0047] The circulation pipeline 3 is connected to the third branch 24 of the discharge pipeline 2. It is used to fully mix the thermally runaway combustible gas with the flame-retardant medium in the pipeline. The flame-retardant medium is used to cool and dilute the thermally runaway combustible gas, so that the concentration of combustible gas is reduced to below the combustible concentration.

[0048] The starting device is triggered synchronously by the pressure of the thermal runaway combustible gas released in the first branch 21 of the venting pipeline 2, and sends a start signal to the flame retardant medium release device 4.

[0049] Specifically, the discharge pipe 2 in this application has a structure similar to a tee, see [link / reference]. Figure 3 , 4 It includes a first branch 21, a second branch 22, and a third branch 24. The first branch 21 and the third branch 24 form a straight-through structure. The first branch 21 is connected to the pressure relief port of the battery 1 through a connection interface 23. Typically, a pressure relief diaphragm or pressure relief valve is installed on the pressure relief port of the battery 1. To prevent gas backflow, a first gas check valve 6 is also installed on the first branch 21. This first gas check valve 6 only allows thermal runaway combustible gas to flow from the pressure relief port of the battery 1 to the third branch 24. The third branch 24 is connected to the mixed gas inlet 31 of the circulation pipeline 3. The outlet end of the second branch 22 is connected to the connection point between the first branch 21 and the second branch 22. The second branch 22 is also connected to the flame retardant medium release device 4. Thus, after the flame retardant medium release device 4 is activated, it releases the flame retardant medium, which is transported to the third branch 24 through the second branch 22, so that the flame retardant medium and the thermal runaway combustible gas output from the first branch 21 are initially mixed in the third branch 24. To further ensure effective gas mixing, the diameter of the third branch 24 is designed to be larger than that of the first branch 21 and the second branch 22, while the diameters of the first branch 21 and the second branch 22 are equal. The diameter of the third branch 24 is 1.5 to 3 times that of the first branch 21. Furthermore, to prevent backflow of the mixed gas, a second gas check valve 7 is installed at the connection between the third branch 24 and the circulation pipeline 3.

[0050] To further explain, in order to filter the solid particles released during thermal runaway, a filter material is installed in the inner cavity of the first branch 21. The thickness of the filter material does not exceed the diameter of the first branch 21. The filter material can be either rock wool or glass fiber wool.

[0051] To further explain, multiple baffles 25 are installed inside the third branch 24 to turbulent and mix the gas mixture, enabling it to achieve a preliminary mixing state. To ensure smooth flow and impeded mixing of the flame-retardant medium and the thermally runaway combustible gas, the baffles 25 are relatively staggered within the third branch 24, with the spacing between them not exceeding the pipe diameter. Individual baffles can also be tilted at an angle of 5-15°. Furthermore, the baffles 25 can be semi-circular, fan-shaped, or crescent-shaped, and their projected area in the pipeline does not exceed two-thirds and is not less than half the cross-section of the third branch 24, ensuring that the combustible gas and flame-retardant medium achieve preliminary mixing before entering the circulation pipeline 3.

[0052] See Figure 5The circulation pipeline 3 in this application is an annular pipeline 33, which can be a rectangular annular pipeline 33, a circular annular pipeline 33, or a triangular annular pipeline. A mixed gas inlet 31 is opened at the bottom of the annular pipeline, and a mixed gas outlet 32 ​​is opened at the top of the annular pipeline, allowing the mixed thermal runaway combustible gas to circulate within the annular pipeline 33. The circulation pipeline extends the flow path of the mixed gas, allowing for thorough mixing of the flame-retardant medium and the thermal runaway combustible gas under pressure-limited conditions. To ensure pressure-limited circulation of the mixed gas in the circulation pipeline 3, a safety valve 8 is connected to the mixed gas outlet 32 ​​via a pipe joint 34. The opening pressure of the safety valve 8 is 0.8–1.0 MPa, and the safety valve 8 can intermittently open and close according to the pressure within the circulation pipeline 3, ensuring that the mixed gas within the circulation pipeline 3 remains under pressure.

[0053] The starting device of this application includes a negative contact 9 and a positive contact 10 installed inside the cavity of the first branch 21. The negative contact 9 and the positive contact 10 are arranged opposite each other and are electrically connected to the flame-retardant medium release device 4 via leads, thereby activating the flame-retardant medium release device 4. Considering the electrical safety of the negative contact 9 and the positive contact 10, insulation layers are provided at the connection ends of the negative contact 9 and the positive contact 10 with the leads, as well as at the connection between the leads and the wall of the first branch 21, to provide insulation protection. The spacing between the negative contact 9 and the positive contact 10 is referenced to be 5-8 mm, specifically to meet the pressure impact of thermal runaway combustible gas to ensure contact. The negative contact 9 and the positive contact 10 can be made of magnetic metal materials such as iron alloys, iron, cobalt, nickel, and other conductive magnetic metals, with a thickness of 0.5-1.5 mm, to facilitate stable contact between the two contacts and ensure stable operation during pressure relief. The material and size specifications of the negative electrode contact 9 and the positive electrode contact 10 are adjusted according to the diameter of the first branch 21. Their contact area does not exceed half of the cross-sectional area of ​​the first branch 21 to ensure that they can make contact and conduct electricity, but without affecting the airflow.

[0054] The aforementioned flame-retardant medium release device 4 includes a power supply 5 and a start switch connected to the power supply 5, see [link to relevant documentation]. Figure 2 The negative contact 9 is connected to the negative terminal of the power supply 5, and the positive contact 10 is connected to the start switch, which is connected to the positive terminal of the power supply 5. When the negative contact 9 and the positive contact 10 come into contact, the starting circuit of the flame retardant medium release device 4 is activated, the start switch is opened, and the flame retardant medium is released normally. That is, the impact force of the thermal runaway flammable gas release causes the negative contact 9 and the positive contact 10 to come into contact, activating the start circuit and releasing the flame retardant medium. This achieves synchronous activation of the pressure relief of battery unit 1 and the release of the flame retardant medium (with a time interval of no more than 2 seconds), ensuring the flame retardant dilution effect. Further explanation: the start switch can also be replaced by a solenoid valve 11.

[0055] The flame retardant medium released into the aforementioned flame retardant medium 4 is mainly one or more of heptafluoropropane, nitrogen, perfluoropropane, perfluorobutane, perfluorohexane, perfluoroacetone, or perfluorohexanone. However, when multiple mixtures are used, the compatibility of the materials and their stability under normal temperature and pressure conditions must be met, which is a known technology.

[0056] In use, the impact force of the thermal runaway flammable gas from battery 1 causes the positive electrode contact 10 and the negative electrode contact 9 to come into contact, activating the start-up circuit of the flame retardant medium release device 4 and simultaneously releasing the flame retardant medium into the second branch 22. The flame retardant medium in the second branch 22 and the thermal runaway flammable gas from the first branch 21 are initially mixed in the third branch 24 and then enter the circulation pipeline 3. Under the pressure-limited state of the circulation pipeline 3, the gas circulates and mixes thoroughly within the pipeline, achieving the purpose of diluting, flame retarding, and cooling the thermal runaway flammable gas using the flame retardant medium. When the pressure in the circulation pipeline 3 reaches the pressure threshold of the safety valve 8, the safety valve 8 opens, discharging the mixed gas or releasing it into the gas collection device, ensuring the safe release of the thermal runaway flammable gas from battery 1 and effectively avoiding secondary disasters such as explosions and fires caused by the thermal runaway of battery 1.

[0057] Example 1

[0058] In this embodiment, the venting pipe 2 has a T-shaped structure, including a first branch 21, a second branch 22, and a third branch 24. The first branch 21 and the third branch 24 form a straight-through structure. The first branch 21 is connected to the pressure relief port of the battery 1, and the third branch 24 is connected to the mixed gas inlet 31 of the circulation pipe 3. The outlet end of the second branch 22 is connected to the connection point between the first branch 21 and the second branch 22, and the second branch 22 is connected to the flame-retardant medium release device 4. The inner diameter of the first branch 21 and the second branch 22 is 25 mm, and the inner diameter of the third branch 24 is 50 mm. The inner cavity of the first branch 21 is filled with rock wool with a thickness of 20 mm to filter the thermal runaway combustible gas. Four crescent-shaped baffles 25 are installed inside the third branch 24 to turbulent and mix the gas mixture, so that it can reach a preliminary mixing state. The thickness of the baffle 25 is 0.3mm, and the projected area of ​​the baffle in the third branch 24 is two-thirds of the cross-section of the third branch 24, ensuring smooth gas flow.

[0059] In this embodiment, the circulation pipeline 3 is a rectangular annular pipeline 33. A mixed gas inlet 31 is located at the bottom of the annular pipeline, and a mixed gas outlet 32 ​​is located at the top of the annular pipeline. This allows the mixed thermal runaway combustible gas to circulate within the annular pipeline 33, extending the flow path and ensuring thorough mixing of the flame-retardant medium and the thermal runaway combustible gas under pressure-limited conditions. To ensure pressure-limited circulation of the mixed gas in the circulation pipeline 3, a safety valve 8 is installed at the mixed gas outlet 32. The opening pressure of the safety valve 8 is 1.0 MPa. The safety valve 8 can intermittently open and close according to the pressure within the circulation pipeline 3, ensuring that the mixed gas within the circulation pipeline 3 remains under pressure.

[0060] In this embodiment, the distance between the negative electrode contact 9 and the positive electrode contact 10 is 5mm. They are made of iron alloy with a thickness of 1mm. It is best if their contact area is one-third of the cross-sectional area of ​​the first branch 21 to ensure that they can make contact and conduct electricity, but without affecting the airflow.

[0061] Example 2

[0062] In this embodiment, the venting pipe 2 has a T-shaped structure, including a first branch 21, a second branch 22, and a third branch 24. The first branch 21 and the third branch 24 form a straight-through structure. The first branch 21 is connected to the pressure relief port of the battery 1, and the third branch 24 is connected to the mixed gas inlet 31 of the circulation pipe 3. The outlet end of the second branch 22 is connected to the connection point between the first branch 21 and the second branch 22, and the second branch 22 is connected to the flame-retardant medium release device 4. The inner diameter of the first branch 21 and the second branch 22 is 30 mm, and the inner diameter of the third branch 24 is 75 mm. The inner cavity of the first branch 21 is filled with rock wool with a thickness of 25 mm to filter the thermal runaway combustible gas. Three semi-circular baffles 25 are installed inside the third branch 24. The baffles 25 are tilted upward at 10° along the gas flow direction to turbulent and mix the gas mixture, so that it can reach a preliminary mixing state. The thickness of the baffles 25 is 0.5mm. The projected area of ​​the baffles in the third branch 24 is half of the cross-section of the third branch 24 to ensure smooth gas flow.

[0063] In this embodiment, the circulation pipeline 3 is a rectangular annular pipeline 33. A mixed gas inlet 31 is located at the bottom of the annular pipeline, and a mixed gas outlet 32 ​​is located at the top of the annular pipeline. This allows the mixed thermal runaway combustible gas to circulate within the annular pipeline 33, extending the flow path and ensuring thorough mixing of the flame-retardant medium and the thermal runaway combustible gas under pressure-limited conditions. To ensure pressure-limited circulation of the mixed gas in the circulation pipeline 3, a safety valve 8 is installed at the mixed gas outlet 32. The opening pressure of the safety valve 8 is 0.8 MPa. The safety valve 8 can intermittently open and close according to the pressure within the circulation pipeline 3, ensuring that the mixed gas within the circulation pipeline 3 remains under pressure.

[0064] In this embodiment, the distance between the negative electrode contact 9 and the positive electrode contact 10 is 8mm. They are made of iron alloy with a thickness of 1.5mm. Their contact area is half of the cross-sectional area of ​​the first branch 21, which ensures that they can make contact and conduct electricity, but does not affect the airflow.

[0065] The starting device of this application can also be replaced by a commercially available pressure sensor, and is not limited to the structure of the negative contact 9 and the positive contact 10 of this application.

[0066] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Other modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and examples shown and described herein.

Claims

1. A thermal runaway safety protection structure for a high-capacity battery, characterized by, The application relates to a battery thermal runaway gas dilution device. The battery thermal runaway gas dilution device comprises a release pipeline (2) in communication with a pressure release port of a battery (1) unit for discharging thermal runaway flammable gas; a circulation pipeline (3) connected with the outlet of the release pipeline (2) for diluting the thermal runaway flammable gas; a fire-retardant medium releasing device (4) in communication with the release pipeline (2) for releasing fire-retardant medium capable of diluting the thermal runaway flammable gas; a starting device synchronously triggered by the gas pressure in the release pipeline (2) and sending a starting signal to the fire-retardant medium releasing device (4); the starting device comprises a negative contact piece (9) and a positive contact piece (10) oppositely arranged in a first branch (21) of the release pipeline (2), and the negative contact piece (9) and the positive contact piece (10) are electrically connected with the fire-retardant medium releasing device (4); the starting device further comprises a power supply (5), the negative contact piece (9) is connected with the negative pole of the power supply (5), and the positive contact piece (10) is connected with the positive pole of the power supply (5) through a starting switch or an electromagnetic valve (11) of the fire-retardant medium releasing device (4); the negative contact piece (9) and the positive contact piece (10) are respectively fixedly connected with the first branch (21) of the release pipeline (2) through an insulating layer, and the distance between the negative contact piece (9) and the positive contact piece (10) meets the requirement that the thermal runaway flammable gas pressure impact makes the two contact. The circulation pipeline (3) is a ring pipeline (33), and a mixed gas inlet (31) and a mixed gas outlet (32) are arranged on the opposite sides of the ring pipeline (33) respectively, so that the mixed thermal runaway flammable gas circulates in the ring pipeline (33) to prolong the thread. A second gas check valve (7) is arranged on the mixed gas inlet (31) and is in communication with the release pipeline (2) through the second gas check valve (7); and a safety valve (8) is arranged on the mixed gas outlet (32). The release pipeline (2) comprises a first branch (21), a second branch (22) and a third branch (24), the first branch (21) and the third branch (24) form a straight-through structure, the first branch (21) is in communication with the pressure release port of the battery (1), the third branch (24) is in communication with the mixed gas inlet (31) of the circulation pipeline (3), the outlet end of the second branch (22) is in communication with the connection point of the first branch (21) and the second branch (22), and the second branch (22) is in communication with the fire-retardant medium releasing device (4). A plurality of spoiler plates (25) are arranged in the inner cavity of the third branch (24), and the plurality of spoiler plates (25) are distributed in a staggered mode. The spoiler plates (25) are in a semicircular, fan-shaped or crescent-shaped structure. The negative contact piece (9) and the positive contact piece (10) are made of magnetic metal material.

2. The thermal runaway safety protection structure of the large capacity battery according to claim 1, wherein, The fire-retardant medium releasing device (4) is internally provided with fire-retardant medium capable of diluting the thermal runaway flammable gas.

3. The thermal runaway safety protection structure for large capacity batteries of claim 2, wherein, The fire-retardant medium is one or more of heptafluoropropane, nitrogen, perfluoropropane, perfluorobutane, perfluorohexane, perfluoropropanone or perfluorohexanone.

4. The thermal runaway safety protection structure of the large capacity battery according to claim 3, characterized in that, The inner cavity of the first branch (21) is provided with filter material, and the filter material is rock wool or glass fiber cotton.

5. The thermal runaway safety protection structure for large capacity batteries of claim 4, wherein, ​ 6. The thermal runaway safety protection structure of the large capacity battery according to claim 5, wherein, ​ 7. The thermal runaway safety protection structure for large format batteries of claim 1, wherein, ​ 8. The thermal runaway safety protection structure for large format batteries of claim 1, wherein, ​ 9. The thermal runaway safety protection structure for large format batteries of claim 8, wherein, ​ 10. The thermal runaway safety protection structure for large format batteries of claim 1, wherein, ​

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