Safety structure of large capacity battery

Abstract

The application discloses a safety structure of a large-capacity battery, which comprises a battery main body, a pressure relief port arranged on the battery main body, and a fire-fighting cooling cavity arranged outside the pressure relief port and used for inhibiting and cooling combustible substances at high temperatures; the fire-fighting cooling cavity is connected with the pressure relief port, and the pressure relief port is sealed and isolated from the fire-fighting cooling cavity through a pressure relief film. When the battery is in thermal runaway and the pressure relief port is opened, various substances in the battery are sprayed outward, pass through the fire-fighting cavity, and are non-flammable, and the non-flammable gas is cooled by the substances in the cooling cavity after passing through the cooling cavity, and then is discharged through an exhaust port, so that the explosion, ignition and secondary disasters caused by the combustible gas leakage of the battery due to the thermal runaway are avoided.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to a safety pressure relief structure for large-capacity batteries. Background Technology

[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] Thermal aerosol fire extinguishing devices are characterized by their small size, high extinguishing efficiency, wide operating temperature range, and pressureless storage, making them widely used in various fields. However, products that integrate thermal aerosol extinguishing agents directly with large-capacity lithium batteries into a single structure are not yet available on the market. This invention combines the advantages of thermal aerosol fire extinguishing devices—small size and good temperature resistance—with the ability to prevent combustion of flammable materials during lithium battery thermal runaway. By combining these two features, it avoids the risk of combustion and explosion of the released materials after lithium battery thermal runaway.

[0005] Most cases of applying thermal aerosol fire extinguishing agents to lithium batteries involve determining the required amount of thermal aerosol fire extinguishing equipment based on the volume of the battery compartment and the extinguishing capacity of the thermal aerosol fire extinguishing agent. This method of fire extinguishing presents the following problems: 1. Unlike ordinary fires, the process of battery thermal runaway continuously generates flammable gases and a large amount of heat. If the thermal aerosol fire extinguishing agent is activated simultaneously with the battery thermal runaway, the gases continuously generated during the battery thermal runaway will constantly push the thermal aerosol fire extinguishing agent out of the battery compartment. Therefore, designing the amount of thermal aerosol fire extinguishing equipment solely based on the size of the battery compartment is clearly insufficient to extinguish battery fires; 2. Existing thermal aerosol fire extinguishing equipment is placed at a certain distance from the outside of the battery casing. This placement method may not be able to promptly suffocate the flammable gases ejected during battery thermal runaway.

[0006] Patent CN212700167U and others describe a fire-fighting chamber on the outside of the battery pack, 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 on the battery. However, when extinguishing a fire in this way, because the temperature during battery thermal runaway is high and the time is long, there is a possibility that the pressurized fire extinguishing agent may explode, or the fire extinguishing agent may be released prematurely, failing to achieve the purpose of extinguishing the fire. Summary of the Invention

[0007] To solve the above-mentioned technical problems, the technical solution adopted in this application is as follows:

[0008] This application provides a safety structure for a large-capacity battery, including a battery body, a pressure relief port disposed on the battery body, and a fire-fighting cooling chamber disposed outside the pressure relief port for suppressing and cooling high-temperature flammable substances; the fire-fighting cooling chamber is connected to the pressure relief port, and the pressure relief port and the fire-fighting cooling chamber are sealed and isolated by a pressure relief membrane. The fire-fighting cooling chamber includes a fire-fighting chamber connected to the pressure relief port, and a cooling chamber connected to the fire-fighting chamber; a porous partition is provided between the fire-fighting chamber and the cooling chamber.

[0009] Furthermore, in the embodiments provided in this application, the fire-fighting chamber is equipped with a fire extinguishing assembly; the fire extinguishing assembly includes a temperature-sensing activation device for detecting battery temperature, and a thermal aerosol fire extinguishing agent unit connected to the temperature-sensing activation device. The thermal aerosol fire extinguishing agent unit is provided with a flame-retardant silicone rubber coating layer. The temperature-sensing activation device is a temperature-sensing cable activation device, or an electric activation device.

[0010] Furthermore, in the embodiments provided in this application, the pressure relief membrane is a metal diaphragm.

[0011] Furthermore, in the embodiments provided in this application, the cooling cavity is filled with one or more combinations of ceramic balls, honeycomb ceramic sheets, graphite rods, and porous ceramics.

[0012] Furthermore, in the embodiments provided in this application, the cooling chamber is provided with an exhaust port. A moisture-proof membrane is provided on the exhaust port, and the moisture-proof membrane can seal the exhaust port. An exhaust pipe or an airbag can be connected to the outside of the exhaust port. The beneficial effects of this invention are:

[0013] When a battery experiences thermal runaway, causing the pressure relief vent to open and various substances inside the battery to be released outwards, the first substances reach the fire-fighting chamber. The high-temperature substances inside the battery activate the temperature-sensing activation device of the thermal aerosol extinguishing agent, releasing highly effective extinguishing substances. These highly effective extinguishing substances mix with the various substances inside the battery. Due to the chemical inhibition effect of the aerosol extinguishing agent, the released substances are non-flammable. Furthermore, the release time of this thermal aerosol extinguishing substance is longer than the gas release time during battery thermal runaway, ensuring that the released substances remain non-flammable even during battery thermal runaway. This non-flammable gas is then cooled by substances in the cooling chamber before being discharged through the exhaust port, thus preventing secondary disasters such as explosions and fires caused by flammable gas leakage due to battery thermal runaway.

[0014] Other advantages, objectives and features of this application will be partly apparent from the description below, and partly understood by those skilled in the art through study and practice of this application. Attached Figure Description

[0015] 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.

[0016] Figure 1 This is an overall structural diagram of the cylindrical high-capacity battery safety structure of Embodiment 1 of this application.

[0017] Figure 2 This is an overall structural diagram of the square large-capacity battery safety structure of Embodiment 2 of this application.

[0018] Explanation of reference numerals in the attached figures:

[0019] Positive terminal 11 / 21; Negative terminal 111 / 211; Battery body 110 / 210; Pressure relief port 18 / 28; Pressure relief membrane 19 / 29; Fire suppression chamber 15 / 25; Porous separator 14 / 24; Cooling chamber 13 / 23; Exhaust port 12 / 22; Starting device 16 / 26; Flame retardant coating material 213. Detailed Implementation

[0020] The present application 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.

[0021] The technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 , 2 As shown, this application provides a safety structure for a large-capacity battery, including a battery body, a pressure relief port disposed on the battery body, and a fire-fighting cooling chamber disposed outside the pressure relief port for suppressing and cooling high-temperature flammable substances; the fire-fighting cooling chamber is connected to the pressure relief port, and the pressure relief port and the fire-fighting cooling chamber are sealed and isolated by a pressure relief membrane. The fire-fighting cooling chamber includes a fire-fighting chamber connected to the pressure relief port, and a cooling chamber connected to the fire-fighting chamber; a porous partition is provided between the fire-fighting chamber and the cooling chamber.

[0023] Furthermore, in the embodiments provided in this application, the fire-fighting chamber is equipped with a fire extinguishing assembly; the fire extinguishing assembly includes a temperature-sensing activation device for detecting battery temperature, and a thermal aerosol fire extinguishing agent unit connected to the temperature-sensing activation device. The thermal aerosol fire extinguishing agent unit is provided with a flame-retardant silicone rubber coating layer. The temperature-sensing activation device is a temperature-sensing cable activation device, or an electric activation device.

[0024] Furthermore, in the embodiments provided in this application, the pressure relief membrane is a metal diaphragm.

[0025] Furthermore, in the embodiments provided in this application, the cooling cavity is filled with one or more combinations of ceramic balls, honeycomb ceramic sheets, graphite rods, and porous ceramics.

[0026] Furthermore, in the embodiments provided in this application, the cooling chamber is provided with an exhaust port. A moisture-proof membrane is provided on the exhaust port, and the moisture-proof membrane can seal the exhaust port. An exhaust pipe or an airbag can be connected to the outside of the exhaust port.

[0027] Example 1

[0028] like Figure 1As shown, a safety structure for a cylindrical high-capacity battery, such as... Figure 1 As shown, the device includes a fire-fighting chamber 15 and a cooling chamber 13. The positive electrode 11 and negative electrode 111 of the high-capacity battery 110 are located on the top and bottom surfaces of the cylindrical battery 110. A pressure relief port 18 is located on the top surface of the cylindrical battery casing. The pressure relief port 18 seals the battery into a closed structure through a pressure relief membrane 19. The fire-fighting chamber 15 is located on the top of the battery, adjacent to the outside of the pressure relief port 18. The cooling chamber 13 is located above the fire-fighting chamber 15, with a perforated metal plate 14 between the fire-fighting chamber 15 and the cooling chamber 13. An exhaust port 12 is located on the upper part of the cooling chamber. The fire-fighting chamber 15 is filled with a thermal aerosol extinguishing agent. This thermal aerosol extinguishing agent uses potassium nitrate as an oxidizer and is coated with flame-retardant silicone rubber to ensure orderly combustion. The thermal aerosol extinguishing agent is activated by a temperature-sensing activation device 16 at a starting temperature of 170°C. When the battery experiences thermal runaway, the release time of the thermal aerosol extinguishing agent must be greater than 2 minutes, and also greater than the time it takes for flammable gases to be released during battery thermal runaway. This must be addressed by filling the cooling chamber. A moisture-proof film is pasted on the top vent of the ceramic ball.

[0029] When a battery experiences thermal runaway, causing the pressure relief vent to open and various substances inside the battery to be released outwards, the first substances reach the fire-fighting chamber. The high-temperature substances inside the battery activate the temperature-sensing activation device of the thermal aerosol extinguishing agent, releasing highly effective extinguishing substances. These highly effective extinguishing substances mix with the various substances inside the battery. Due to the chemical inhibition effect of the aerosol extinguishing agent, the released substances are non-flammable. Furthermore, the release time of this thermal aerosol extinguishing substance is longer than the gas release time during battery thermal runaway, ensuring that the released substances remain non-flammable even during battery thermal runaway. This non-flammable gas is then cooled by substances in the cooling chamber before being discharged through the exhaust port, thus preventing secondary disasters such as explosions and fires caused by flammable gas leakage due to battery thermal runaway.

[0030] Example 2

[0031] like Figure 2 As shown, a safety structure for a square high-capacity battery, such as Figure 2As shown, the battery includes a fire-fighting chamber 25 and a cooling chamber 23. The positive electrode 21 and negative electrode 211 of the large-capacity battery 210 are located on the same side of the top surface of the square battery. The pressure relief port 28 is located in the middle of the side casing of this square battery. The pressure relief port 28 seals the battery into a closed structure through the pressure relief membrane 29. The fire-fighting chamber 25 is located on the side of the battery, adjacent to the outside of the pressure relief port. The cooling chamber 23 is located on the upper part of the fire-fighting chamber 25. A porous metal plate 24 is provided between the fire-fighting chamber 25 and the cooling chamber 23. An exhaust port 22 is located on the upper part of the cooling chamber. The fire-fighting chamber 25 is filled with a thermal aerosol extinguishing agent. This thermal aerosol extinguishing agent uses potassium nitrate and strontium nitrate as oxidants and is coated with flame-retardant silicone rubber 213 to enable orderly combustion. The thermal aerosol extinguishing agent is activated by a temperature-sensing activation device 26 with an activation temperature of 170°C. When the battery experiences thermal runaway, the time for the thermal aerosol extinguishing agent to release extinguishing substances is greater than 5 minutes, and also greater than the time for the flammable gas to be released during battery thermal runaway. The cooling chamber is filled with honeycomb ceramic sheets, and an exhaust pipe is installed at the top exhaust port to discharge the released mixed gas to a safe area.

[0032] When a battery experiences thermal runaway, causing the pressure relief vent to open and various substances inside the battery to be released outwards, the first substances reach the fire-fighting chamber. The high-temperature substances inside the battery activate the temperature-sensing activation device of the thermal aerosol extinguishing agent, releasing highly effective extinguishing substances. These highly effective extinguishing substances mix with the various substances inside the battery. Due to the chemical inhibition effect of the aerosol extinguishing agent, the released substances are non-flammable. Furthermore, the release time of this thermal aerosol extinguishing substance is longer than the gas release time during battery thermal runaway, ensuring that the released substances remain non-flammable even during battery thermal runaway. This non-flammable gas is then cooled by substances in the cooling chamber before being discharged to a safe area through the exhaust port. This prevents secondary disasters such as explosions and fires caused by flammable gas leakage due to battery thermal runaway.

[0033] Although the embodiments of this application have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this application. 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, this application is not limited to the specific details and examples shown and described herein.

Claims

1. A safety structure for a high-capacity battery, comprising a battery body and a pressure relief port disposed on the battery body, characterized in that, It also includes a fire-fighting cooling chamber located outside the pressure relief port and used to suppress and cool down high-temperature flammable materials; The fire-fighting cooling chamber is connected to the pressure relief port, and the pressure relief port and the fire-fighting cooling chamber are sealed and isolated by a pressure relief membrane; The fire-fighting cooling chamber includes a fire-fighting chamber connected to the pressure relief port and a cooling chamber connected to the fire-fighting chamber; the fire-fighting chamber is located on the top of the battery adjacent to the outside of the pressure relief port, or the fire-fighting chamber is located on the side of the battery adjacent to the outside of the pressure relief port; the cooling chamber is located above the fire-fighting chamber, and the cooling chamber is provided with an exhaust port, and the exhaust port is provided with a moisture-proof membrane; A perforated partition is provided between the fire-fighting chamber and the cooling chamber; The fire-fighting chamber is equipped with a fire extinguishing assembly; the fire extinguishing assembly includes a temperature-sensing activation device for detecting battery temperature, and a thermal aerosol fire extinguishing agent unit connected to the temperature-sensing activation device; when the battery is thermally runaway, the thermal aerosol fire extinguishing agent unit releases the fire extinguishing substance for a longer time than the time it releases flammable gas, so that the sprayed substance is non-flammable, and the non-flammable gas is cooled by the substance in the cooling chamber after passing through the cooling chamber, and then discharged through the exhaust port; The exhaust port is externally connected to an exhaust pipe or an airbag.

2. The safety structure of a high-capacity battery as described in claim 1, characterized in that, The thermal aerosol extinguishing agent unit is equipped with a flame-retardant silicone rubber coating layer.

3. The safety structure of a high-capacity battery as described in claim 1, characterized in that, The temperature-sensing start device is either a temperature-sensing cable start device or an electric start device.

4. The safety structure of a high-capacity battery as described in claim 1, characterized in that, The pressure relief membrane is a metal diaphragm.

5. The safety structure of a high-capacity battery as described in claim 1, characterized in that, The cooling chamber is filled with one or more of the following: ceramic balls, honeycomb ceramic sheets, graphite rods, and porous ceramics.

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