Acoustic low-pressure water mist fire extinguishing device for lithium ion power battery box of electric motor coach
Technical Field
The invention belongs to the technical field of fire extinguishing devices, and particularly relates to an acoustic low-pressure water mist fire extinguishing device for a lithium ion power battery box of an electric motor coach.
Background
Since 2012, new energy automobile product technology is continuously broken through and matured, and new energy automobile sales volume is increasing. But car safety accidents face a multiplied situation. According to statistics, 29 new energy vehicles have fire accidents in 2016, and 40 vehicles are in total, wherein the accident rate of new energy passenger vehicles and special vehicles reaches 97%, and compared with the reserved quantity of 40 thousands of new energy vehicles in the end of the year, the calculated related ratio is about 50 PPM. According to the ratio, when the new energy automobile keeping quantity reaches 500 thousands in 2020, the fire accidents are equivalent to 250 times. From the consequences of each fire accident that has occurred, serious casualty accidents are inevitable at this frequency, and the consequences are not imaginable. According to public data arrangement, the electric automobile fire accident 9 commonly occurs at home and abroad in the last half of 2017, the total number of vehicles is up to 98, and the safety problem caused by new energy automobiles becomes a hotspot and a difficulty in the automobile industry.
The current situation and problems of new energy automobile safety accidents gradually become new topics of the automobile industry or will hinder the development and popularization of electric automobiles. The reasons for causing the safety accidents of the new energy automobile are that the whole automobile non-electric vehicle platform is modified, so that the bearing hidden danger of a battery, the defects of a power battery system (including electrochemical reaction problems), the lack of battery materials, the improper use of the battery and the like are caused. The spontaneous combustion case of the new energy automobile caused by the power battery is mainly caused by mechanical safety, electrical safety, functional safety and chemical safety, wherein the electrical safety and the chemical safety are particularly outstanding, the spontaneous combustion case is more embodied under the condition that the new energy automobile is placed in a static state, and the functional safety is more and more emphasized. Today, the degree of automotive electronics is higher and higher, the electrical safety is relatively more mature, but the functional safety and the chemical safety become new issues. For example, in the aspect of functional safety, the battery system cannot monitor and alarm faults in advance due to incomplete management, so that overcharge, short circuit and leakage of the battery are caused, and finally thermal runaway, spontaneous combustion and fire are caused.
The Chinese patent application 'a special gas fire extinguishing device for a lithium ion battery box and a fire extinguishing implementation method' (publication number CN 107320871A) applies that a fire extinguishing agent is a chemical fire extinguishing agent, and the fire extinguishing mechanism mainly comprises the steps of absorbing a large amount of heat when the fire extinguishing agent is sprayed, achieving the purpose of extinguishing a fire by cooling, and failing to achieve a quick and accurate fire extinguishing effect. Most of parts adopted by the fire extinguishing device are specially manufactured, the universality is poor, and the cost is high.
At present, the domestic water mist fire extinguishing system generally adopts high-pressure and medium-pressure technologies to realize the refinement of mist drops, and the high-pressure and medium-pressure water mist system cannot be applied to a passenger car due to the limitation of equipment.
On the second international lithium battery fire safety seminar, the expert summarizes the current lithium battery fire extinguishing system as follows:
(1) after the fire extinguishing systems such as carbon dioxide, heptafluoropropane, aerosol, dry powder and the like are sprayed, although flames can be extinguished, the efficiency is different, the surface temperature of the battery is quickly raised to 400-500 ℃, and the phenomenon of re-combustion occurs;
(2) after the water mist and the perfluorohexanone fire extinguishing system is sprayed, the fire can be extinguished quickly, the surface temperature is reduced quickly, and the fire extinguishing system has a good cooling effect and a certain afterburning resistance effect.
(3) The requirements of the fire extinguishing system and the fire extinguishing agent are quick and accurate fire extinguishing, efficient cooling, cleanness, energy conservation, re-combustion resistance and insulation.
However, the acoustic low-pressure water mist fire extinguishing device for the lithium battery of the passenger car is still a blank up to now.
Disclosure of Invention
The invention aims to overcome the defects of the existing fire extinguishing technology for lithium batteries of electric motor coaches, and provides a fire extinguishing device for a lithium ion power battery box of an electric motor coach, which has the advantages of quick and accurate fire extinguishing, efficient cooling, cleaning, energy saving, strong re-combustion resistance and good insulation effect.
The low-pressure water mist fire extinguisher is a fixed fire extinguisher with water as medium and special nozzle to spray water mist under specific working pressure. The system becomes an ideal substitute of the haloalkane extinguishing agent by virtue of the advantages of high extinguishing efficiency, wide application range, environmental protection, no electric damage and the like, and plays an increasingly important role in replacing greenhouse gases such as carbon dioxide and heptafluoropropane.
The technical scheme for realizing the purpose of the invention is as follows:
an acoustic low-pressure water mist fire extinguishing device for a lithium ion power battery box of an electric motor coach comprises a gas storage bottle, a pressure reducing valve, a water storage bottle, a partition control valve, a low-pressure water mist nozzle, a connecting pipeline and a pipe fitting. A container valve and an electromagnetic driving device are installed at the air port of the air storage cylinder, and the pressure reducing valve is connected with the container valve; a bottle valve is connected to the bottle mouth of the water storage bottle, an output air pipe of the pressure reducing valve is connected to the three-way pipe fitting, one end of the split gas is connected to the bottle valve through a first gas conveying pipe, the bottle valve is connected with a second zone control valve through a water conveying pipe, and a water conveying hose of the spray head is connected with the second zone control valve and the low-pressure water mist spray head; the other end of the split gas is connected to the first zone control valve through a second gas pipe and then connected to a spray head gas pipe, and the spray head gas pipe is connected with the low-pressure water mist spray head; the low-pressure water mist spray head is fixed on the shell of the lithium battery box.
The low-pressure water mist fire extinguishing nozzle comprises a bolt, a nut, a body, a cone, a resonance body, a shell and an upper cover, wherein the resonance body and the cone are connected together through the bolt; the cone and the body are connected into a whole by a nut; the upper end of the body is provided with an air inlet, and a sealing gasket is arranged at the connecting position of the nut in consideration of the impact effect of air flow. The shell is in threaded connection with the body, the upper cover is in threaded connection with the shell and the body, a gas distributing hole is formed in the inner wall of the body, and a horn-shaped cavity is formed by the inner conical surface of the body and the outer conical surface of the cone and is communicated with the gas distributing hole. The water diversion slotted hole is arranged at the lower end of the body close to the outer diameter, the water inlet connecting pipe is arranged on the side walls of the shell and the body, the water flow joint hole of the water inlet connecting pipe is communicated with the water diversion slotted hole, the sealing ring for preventing water leakage is arranged at the gap between the body and the shell at the upper position and the lower position of the water flow joint hole, and the gap between the body and the resonance body forms a fine water mist spray outlet. The low-pressure water mist nozzle is a double-fluid low-pressure open nozzle, and gas generates sound waves at the nozzle, so that water flowing out of the nozzle is rapidly atomized for extinguishing fire.
The gas storage cylinder group stores nitrogen with certain pressure, and the electromagnetic driving device on the container valve opens the container valve to release gas after receiving the starting signal. The container valve is provided with a pressure gauge and a safety relief device.
The pressure reducing valve presets pressure reducing outlet pressure, and high-pressure gas released by the gas storage cylinder group is reduced in pressure and then is conveyed to a downstream pipeline. The pressure reducing valve is provided with a pressure gauge.
The water storage bottle group stores water with certain mass, the air inlet end of the bottle valve is provided with a one-way valve, and the water outlet is connected to the partition control valve.
The partition control valve can receive the control signal and automatically open to enable the spray head to spray to the corresponding protection object to implement the fire extinguishing control valve.
The working principle of the invention is as follows:
(1) and the acoustical low-pressure water mist fire extinguishing system of the lithium ion power battery box of the electric motor coach receives a fire extinguishing instruction, starts an electromagnetic driving device on the gas storage cylinder group and simultaneously opens the partition control valve of the corresponding protection area.
(2) The high-pressure gas of the gas storage cylinder group flows out, is decompressed by the decompression valve and then is output.
(3) The gas output by pressure reduction is conveyed to the water storage bottle group through a three-way pipe fitting, one path of the gas is conveyed to the water storage bottle group, the water in the water storage bottle group is pressed out, and the gas flows through the opened zone control valve and is conveyed to the spray head; the other path of gas is delivered to the spray head through a pipeline and a zone control valve.
(4) The low-pressure water mist spray head arranged on the lithium ion battery box can quickly generate water mist under the action of gas, water and sound waves to quickly and accurately extinguish fire.
The invention has the beneficial effects that:
1. compared with other fire extinguishing systems of the same type, the fire extinguishing system can meet the general technical requirements of quick and accurate fire extinguishing, efficient cooling, cleanness, energy conservation, re-combustion resistance and good insulation effect.
2. The method adopts the low-pressure fine water mist spray nozzle to spray mist drops for carrying out particle size distribution test, the average particle size range of the fine water mist generated by the spray nozzle is 50-300 mu m, compared with the existing water mist spray nozzle, the specific surface area of the water mist is improved by millions of times, the fine water mist instantly vaporizes when meeting flames and absorbs heat to form steam, the temperature of a fire scene is reduced, a high-efficiency anoxic environment is formed, and the optimal fire extinguishing principle of cooling, suffocation and dust removal is achieved.
3. The fire extinguishing is rapid, and the fire extinguishing time is less than 1min through practical tests.
4. The invention can not cause short circuit of fire hazard of electrical appliances, and common water can normally extinguish fire below 6000V and is not conductive; if distilled water is selected, the fire can be extinguished under the condition of high pressure of 10KV, and the fire cannot be extinguished and does not conduct electricity, and the explosion reaction with hot oil cannot happen.
5. The system has low pressure grade, is in a low pressure range, reduces the water consumption and meets the requirement of energy conservation.
6. The invention has obvious energy-saving effect:
(1) the dosage of the fire extinguishing agent, namely the dosage of water and gas is greatly reduced.
(2) Due to the adoption of the low-pressure atomization technology, the cost of the fire extinguishing system equipment is greatly reduced.
7. The environment-friendly effect is obvious, and the fire extinguishing agent consists of nitrogen and water and does not contain other chemicals, carbon dioxide and other substances harmful to the environment.
Drawings
FIG. 1 is a schematic view of the overall structure of the apparatus of the present invention.
FIG. 2 is a schematic view of a low pressure fine mist spray head according to the present invention.
In fig. 1: 1-gas storage bottle, 2-container valve, 3-electromagnetic driving device, 4-water storage bottle, 5-bottle valve, 6-pressure reducing valve, 7-three-way pipe fitting, 8-first gas pipe, 9-water pipe, 10-second gas pipe, 11-first zone control valve, 12-nozzle water delivery hose, 13-nozzle gas pipe, 14-low-pressure water mist nozzle, 15-water mist nozzle, 16-lithium battery box, 17-second zone control valve, 18-bolt, 19-nut, 20-body, 21-cone, 22-resonance body, 23-shell, 24-upper cover, 25-water inlet connecting pipe, 26-water inlet and 27-gas inlet.
Detailed Description
The embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in figures 1 and 2, the acoustic low-pressure water mist fire extinguishing device for the lithium ion power battery box of the electric motor coach comprises a gas storage bottle 1, a pressure reducing valve 6, a water storage bottle 4, a first zone control valve 11, a second zone control valve 17, a low-pressure water mist spray head 14, a connecting pipeline and a pipe fitting. A container valve 2 and an electromagnetic driving device 3 are arranged at the air port of the air storage bottle 1, and a pressure reducing valve 6 is connected with the container valve 2; the bottle mouth of the water storage bottle 4 is connected with a bottle valve 5, and an output air pipe of a pressure reducing valve 6 is connected with a three-way pipe fitting 7; one end of the split gas is connected to the cylinder valve 5 through a gas transmission pipe I8, and the cylinder valve 5 is connected with a partition control valve II 17 through a water transmission pipe 9; the other end of the split gas is connected to a first zone control valve 11 through a second gas pipe 10 and then connected to a spray head gas pipe 13, and the spray head gas pipe 13 is connected with a gas inlet 27 of a low-pressure water mist spray head 14; one end of the spray head water delivery hose 12 is connected with a second partition control valve 17, and the other end of the spray head water delivery hose is connected to the low-pressure water mist spray head 14 through a water inlet connecting pipe 25; the low-pressure water mist head 14 is fixed to the casing of the lithium battery box 16.
The low-pressure water mist fire extinguishing nozzle comprises a bolt 18, a nut 19, a body 20, a cone 21, a resonance body 22, a shell 23 and an upper cover 24, wherein the resonance body 22 and the cone 21 are connected together through the bolt 18; the cone 21 and the body 20 are connected into a whole by the nut 19; the upper end of the body 20 is provided with an air inlet 27, and a sealing gasket is provided at the coupling position of the nut 19 in consideration of the impact of the air flow. The shell 23 is in threaded connection with the body, the upper cover 24 is in threaded connection with the shell 23 and the body, a gas diversion hole is formed in the inner wall of the body 20, and a horn-shaped cavity is formed by the inner conical surface of the body 20 and the outer conical surface of the cone and is communicated with the gas diversion hole. A water diversion slotted hole is arranged at the lower end of the body near the outer diameter, a water inlet connecting pipe 25 is arranged on the side walls of the shell 23 and the body 20, a water flow joint hole of the water inlet connecting pipe 25 is communicated with the water diversion slotted hole, a sealing ring for preventing water leakage is arranged at the gap between the body and the shell at the upper and lower positions of the water flow joint hole, and a fine water spray outlet 15 is formed at the gap between the body and the resonance body. The resonator body 20 is specially designed to comply with acoustic principles.
The working flow of the device of the invention for extinguishing fires is described below with reference to fig. 1 and 2:
the gas storage bottle 1 stores nitrogen with the pressure of 10MPa, the water storage bottle 4 stores water with certain mass, and the container valve 2, the first partition control valve 11 and the second partition control valve 17 are in a closed state;
when a fire extinguishing instruction is received, the electromagnetic driving device 3, the first zone control valve 11 and the second zone control valve 17 on the container valve 2 are rapidly opened, high-pressure gas in the gas storage bottle 1 flows out, the pressure is reduced to 0.8MPa +/-0.2 MPa through the pressure reducing valve 6, and the reduced-pressure gas is divided into two paths through the three-way pipe fitting 7;
one path of gas enters the water storage bottle 4 through the gas transmission pipe I8 and the bottle valve 5, the water of the water storage bottle 4 is pressed out to the water transmission pipe 9, and the water passes through the opened water path partition control valve 17 and flows through the water transmission hose 12 of the spray head to reach the low-pressure water mist spray head 14;
the other path of gas passes through the opened gas path partition control valve I11 through the gas transmission pipe II 10 and then reaches the low-pressure water mist spray head 14 through the spray head gas transmission pipe 13.
The fire extinguishing process with the generation of water mist according to the invention is described further below with reference to fig. 2:
the water path and the gas path in the low-pressure water mist fire extinguishing nozzle are separated. The gas with the pressure of 0.5MPa +/-0.3 MPa enters the gas inlet 27 to reach the body 20, is divided by the gas dividing holes, enters the horn-shaped cavity formed by the inner conical surface of the body 20 and the outer conical surface of the cone 21, is sprayed out by secondary division formed by the body 20 and the cone 21, strikes the resonance body 22, and then is sprayed out in a fine water mist mode. Water with the pressure of 0.03MPa-0.1MPa enters the water flow joint from the water inlet 26 and then enters the circular inner ring formed by the shell 23 and the body 20, and because the upper and lower sealing rings are sealed, the water cannot leak from the interior of the fire extinguishing nozzle and then is sprayed out from the water diversion slotted hole. At this time, the water flowing out of the fire extinguishing head is instantaneously atomized into fine mist droplets by the sound waves generated from the resonating body 22, and the fine mist droplets are ejected from the fine mist ejection port 15 and rapidly spread throughout the space.
Tests prove that the average particle size range of the fine water mist generated by the low-pressure fine water mist nozzle 14 is 50-300 mu m, compared with the existing water mist nozzle, the water mist nozzle improves the specific surface area of the water mist by millions times, and instantly vaporizes when encountering flames to absorb heat to form steam, so that the temperature of a fire scene is reduced, a high-efficiency anoxic environment is formed, and the optimal fire extinguishing principle of cooling, suffocating and dust removal is achieved.