JPH04292177A - Method and device for extinguishing fire of sodium-sulfur battery - Google Patents

Abstract

PURPOSE:To rapidly extinguish a fire generated in a sodium-sulfur battery. CONSTITUTION:Gas is supplied from a gas cylinder 12 into a a tank 11 to agitate the inert liquid L and granular fire extinguisher Sa in the tank 11 to prepare a slurry fire extinguisher S when the fire breaks out in a case 1 of the battery. A pump 16 is driven to force feed and supply the slurry fire extinguisher S from the tank 11 to the case 1 of the battery when the internal pressure of the tank 11 rises up to a prescribed value.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a fire extinguishing method and device for a fire in a sodium-sulfur battery, and more specifically, when an abnormality occurs in a sodium-sulfur battery, a chemical reaction occurs between the active materials of the anode and cathode inside the battery. This invention relates to a fire extinguishing method and device for extinguishing fires caused by.

0002

BACKGROUND OF THE INVENTION In recent years, research and development has been progressing on sodium-sulfur batteries that operate at 300 to 350° C. as secondary batteries for electric vehicles and nighttime power storage. This sodium-sulfur battery has excellent characteristics in terms of both performance and economy.In terms of performance, it has a higher theoretical energy density than lead-acid batteries, has no side effects such as the generation of hydrogen or oxygen during charging and discharging, and has two polar The utilization rate of active materials is also high. moreover,
From an economic point of view, metallic sodium and sulfur have the advantage of being inexpensive.

[0003] Moreover, this sodium-sulfur battery is rarely used as a single unit, but a plurality of batteries are connected in series, and a plurality of batteries connected in series are housed in a case. Then, by heating this assembled battery to 300 to 350°C in the case, the active materials, metallic sodium and sulfur, are melted, and in the molten state, the ions of the active materials are moved and electrochemical reactions occur with each other. At the same time, a predetermined amount of electrical energy is obtained.

0004

However, in this conventional sodium-sulfur battery, the solid electrolyte tube inside the battery may be destroyed due to some reason, such as an overcurrent flowing due to an accidental short circuit current. At this time of destruction, the molten metal sodium and molten sulfur, which were separated into the inside and outside by the solid electrolyte tube, come into direct contact, mix with each other, and cause a chemical reaction. This reaction heat causes a problem in that the cover of the battery itself is destroyed and a fire occurs within the case housing the battery. Note that it is not appropriate to use water as an extinguishing agent when a fire occurs because molten metal sodium reacts violently with water.

[0005] The present invention was made by focusing on the problems existing in the conventional technology, and its purpose is to quickly and reliably extinguish fires that occur in sodium-sulfur batteries. An object of the present invention is to provide a method for extinguishing a fire in a sodium-sulfur battery and an apparatus therefor.

[0006]

[Means for Solving the Problems] In order to achieve the above object, in the invention of the fire extinguishing method of claim 1, an inert liquid and a granular fire extinguishing agent are contained in a case housing an assembled battery consisting of a sodium-sulfur battery. This system is characterized by pumping and supplying a slurry-like fire extinguishing agent mixed with In the invention of the fire extinguishing device according to claim 2, a tank containing an inert liquid and a granular extinguishing agent, a stirring means for stirring the inert liquid and granular extinguishing agent in the tank to create a slurry extinguishing agent, and a sodium- Inside the case containing the collective battery made of sulfur batteries,
The present invention is characterized by further comprising a pumping means for pumping and supplying a slurry fire extinguishing agent from the tank.

[0007]

[Function] In the sodium-sulfur battery fire extinguishing system configured as above, if an abnormal reaction occurs in the sodium-sulfur battery and a fire occurs within the case, the inert liquid and granular extinguishing agent will be mixed in the tank. It is stirred to create a slurry fire extinguishing agent. Then, this slurry-like fire extinguishing agent is supplied under pressure from the tank into the case of the assembled battery, and is filled into the gaps between the assembled batteries. When the slurry extinguishing agent is filled in this way, the cooling effect due to the latent heat of vaporization of the inert liquid,
The synergistic effects of the inert gas generated as the inert liquid evaporates to inhibit the reaction between sodium and sulfur, the heat insulating effect of the granular fire extinguishing agent, and the heat dispersion effect of the granular fire extinguisher suppress abnormal reactions in the battery. At the same time, it is possible to prevent the spread of fire to adjacent healthy batteries. Therefore, battery fires can be extinguished quickly and reliably.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fire extinguishing system for a sodium-sulfur battery embodying the present invention will be described in detail below with reference to the drawings. First, to describe the structure of the sodium-sulfur battery, as shown in FIGS. 1 to 3, the case 1 is formed into a square box shape with a double wall structure inside and outside.
A heat insulating material 2 is interposed between the inner and outer walls. The mounting table 3 is disposed at the inner bottom of the case 1 via a support member 4 so as to be located at a predetermined distance from the inner bottom of the case 1 .

The batteries 5 are arranged upright on the upper surface of the mounting table 3, and a plurality of batteries are connected in series and in parallel. electric heater 6
is arranged between the bottom of the case 1 and the mounting table 3, and the temperature inside the case 1 is kept at about 300 to 350 by this electric heater 6.
℃, the metal sodium and sulfur in the battery 5 are melted. The air supply pipe 7 supplies external air and the like into the case 1. The exhaust pipe 8 is provided adjacent to the air supply pipe 7, and the case 1 is
The air inside is exhausted to the outside. And these two pipes 7
, 8 and the temperature control of the electric heater 6, the temperature inside the case 1 is kept at about 300 to 350.
kept at ℃.

The supply pipe 9 is provided at the upper part of the side wall of the case 1, and has a bifurcated supply port 9a formed at its inner end. A slurry fire extinguishing agent S, which will be described later, is supplied into the case 1 via this supply pipe 9. The discharge pipe 10 is provided at the upper part of the side wall of the case 1 so as to be located at a predetermined distance laterally from the supply pipe 9, and the discharge port 10a at the inner end thereof is connected to the supply port 9a of the supply pipe 9.
It is located at the same height as or slightly lower than that. When the slurry-like fire-extinguishing agent S is supplied into the case 1 in excess of a predetermined amount, the excess slurry-like fire-extinguishing agent S is discharged to the outside from the discharge pipe 10.

Next, the configuration of the fire extinguishing system will be described.
As shown in FIGS. 1 and 2, the storage tank 11 is formed into a closed cylindrical shape, and an inert liquid L and a granular fire extinguishing agent Sa are stored therein. A gas cylinder 12 constituting the stirring means is disposed near the storage tank 11, and N2 gas is stored therein. When the gas valve 13 is opened, the gas introduction pipe 1 from the gas cylinder 12
N2 gas is supplied into the storage tank 11 via 4,
While the internal pressure of the storage tank 11 is increased, the inert liquid L and the granular fire extinguishing agent Sa in the storage tank 11 are stirred to create a slurry fire extinguishing agent S.

The liquid feeding pipe 15 is connected to the outer lower part of the storage tank 11, and a supply pipe 9 extending from the case 1 of each sodium-sulfur battery is connected in the middle thereof. A pump 16 constituting a pressure-feeding means is installed on a liquid-feeding pipe 15 in close proximity to the storage tank 11, and when the pump 16 is driven with the main valve 17 open, the slurry fire extinguishing agent S is pumped into the storage tank. The liquid is fed under pressure from inside 11 to liquid sending pipe 15 . A partition valve 18 is provided on the supply pipe 9,
By opening the partition valve 18, the slurry fire extinguishing agent S is supplied under pressure from the liquid sending pipe 15 through the supply pipe 9 into the battery case 1.

Next, the slurry fire extinguishing agent S will be explained in detail. In this example, the mixing ratio of the inert liquid L and the granular fire extinguishing agent Sa in the slurry fire extinguishing agent S is 50 to
The volume ratio is set within the range of 80%:50 to 20%. Further, as the inert liquid L, a fluorine-based inert liquid is used, which is non-flammable and non-conductive, and has a boiling point of 250 to 300°C. When the slurry fire extinguishing agent S is supplied into the battery case 1 at the time of a fire outbreak, most of the inert liquid L in the slurry fire extinguishing agent S evaporates at 250 to 300°C, and due to the latent heat of vaporization. In addition to exhibiting a cooling effect, the inert gas generated during evaporation also suppresses the reaction between sodium and sulfur.

Furthermore, as the granular fire extinguishing agent Sa, a large number of spherical particles are used which are non-reactive with the active material of the battery and the products at the time of fire occurrence, are non-hygroscopic and have insulating properties. ing. Specifically, it is composed of a ceramic material, sand, etc., either singly or in combination, and in this embodiment, ceramic particles are used. Therefore, in detail about the ceramic particles, the particle size of the ceramic particles is preferably in the range of 0.05 to 1.0 mm, and in this example, the particle size of 0.1 mm is used. or,
The surfaces of the ceramic grains are formed to be smooth in order to reduce the coefficient of friction and make it easier to flow into the gaps between the batteries 5. Furthermore, suitable materials include feldspathic ordinary porcelain based on ordinary porcelain, alumina-containing porcelain, cristobalite porcelain, alumina porcelain, zircon porcelain, cordierite porcelain, etc. In this example, feldspathic ordinary porcelain is used. ing. Also, the volume resistivity of these materials decreases slightly with increasing temperature, but is at least 1 MΩ-cm.
It has a volume resistivity of .

[0015] Even if the metallic sodium in the battery 5 is in a solidified state, it cannot contain hydrogen fluoride (HF) or hydrogen chloride (HF).
HCl), hydrogen sulfide (H2S), hydrogen (H), bromine (
Br), fluorine (F), chlorine (Cl), sulfur (S), mercury (Hg), water (H2O), etc., so it is necessary to select and use ceramic grains that do not contain these substances. There is.

[0016] Also, reaction products produced by the oxidation reaction of metallic sodium and sulfur in the battery 5 include sulfur dioxide (SO2), sodium hydroxide (NaOH), sodium oxide (Na2OH), and sodium peroxide ( Na
2 O3 ), sodium sulfide (Na2 NO3 ),
Examples include carbon disulfide (CS2). Furthermore, during the oxidation reaction of metallic sodium and sulfur, nitrogen in the air is oxidized due to the heat of the oxidation reaction, producing nitrogen oxides (NOx).
is generated. Therefore, it is necessary to select and use ceramic grains that do not react with these reaction products.

Next, the operation of the fire extinguishing system for a sodium-sulfur battery constructed as described above will be explained. Now, normally, the inside of the battery case 1 is heated and maintained at about 300 to 350 degrees Celsius by an electric heater 6, and the metallic sodium and sulfur in the single sodium-sulfur battery that constitutes the battery 5 are in a molten state. . In this state, if an abnormal reaction or the like occurs in the sodium-sulfur battery and the internal fixed electrolyte tube is damaged, the molten metal sodium in the fixed electrolyte tube comes into direct contact with the molten sulfur in the anode container and mixes. As a result, the following chemical reaction takes place as the main reaction, and sodium polysulfide, especially sodium trisulfide, is finally produced.

[0018]

[Case 1] 2Na+XS→Na2Sx At this time, a large amount of chemical reaction heat is generated, the cover of the battery 5 itself is thermally destroyed, and metallic sodium and sulfur are
leaks inside. As a result, the metal sodium further reacts with oxygen in the air and the like, resulting in a high temperature state, which in turn causes other batteries 5 to burn out as well.

When a fire occurs in the case 1 as described above, the fire accident is detected by a heat sensor or a gas sensor (not shown), and the power supply to the electric heater 6 in the case 1 is stopped. After that, the gas valve 13 is opened and the gas cylinder 12
N into the storage tank 11 through the gas introduction pipe 14
2 Gas is supplied. As a result, the internal pressure of the storage tank 11 is increased, and the inert liquid L and the granular fire extinguishing agent Sa in the storage tank 11 are stirred to create a slurry fire extinguishing agent S.

When the internal pressure of the storage tank 11 reaches a predetermined value, the main valve 17 is opened and the pump 16 is driven, so that the slurry fire extinguishing agent S is pumped into the storage tank 11.
The liquid is fed under pressure to the liquid feeding pipe 15 from inside. Thereafter, the partition valve 18 corresponding to the case 1 of the battery where the fire occurred is opened, and the slurry extinguishing agent S is fed under pressure into the case 1 from the liquid feed pipe 15 via the supply pipe 9, and the battery pack 5 is The gaps between them are filled.

At this time, the granular fire extinguishing agent Sa in the slurry fire extinguishing agent S is mixed and stirred with the inert liquid L to form a fluid slurry, so that it does not stagnate in the pipes 15 and 9. It is smoothly supplied into the case 1. Further, as shown in FIG. 3, since the supply port 9a of the supply pipe 9 is branched into a forked shape, the slurry fire extinguishing agent S is spread over a wide area inside the case 1 from the forked supply port 9a. Fills and supplies evenly and quickly. Then, as shown in FIG. 3, the case 1 is filled with a predetermined amount of the slurry fire extinguishing agent S, and the liquid level of the slurry fire extinguishing agent S is raised a predetermined distance (for example, about 10 mm) upward from the upper end of the battery pack 5. When the slurry-like fire extinguishing agent S that is subsequently supplied is discharged from the discharge pipe 10 to the outside of the case 1.

[0022] In this way, the slurry extinguishing agent S is
When the inert liquid L in the slurry extinguishing agent S evaporates at 250 to 300°C, the latent heat of evaporation exerts a cooling effect, and the inert liquid generated with evaporation The gas suppresses the reaction between sodium and sulfur. Further, after the inert liquid L evaporates, the granular fire extinguishing agent Sa remains in the case 1, and each battery 5 is shielded by the granular fire extinguishing agent Sa, thereby exerting a heat insulation effect and a heat dispersion effect. Therefore, the cooling effect due to the latent heat of vaporization of the inert liquid L, the reaction suppression effect due to the inert gas generated when the inert liquid L evaporates, the insulation effect due to the granular fire extinguishing agent Sa,
and the synergistic effect of the heat dispersion effect of the granular fire extinguishing agent Sa,
Abnormal battery reactions are suppressed, and a battery fire can be quickly and reliably extinguished by preventing continuation of fire to adjacent batteries.

Note that the present invention is not limited to the configuration of the above-mentioned embodiments; for example, the inert liquid may have a boiling point of approximately 400° C., which is the abnormal heating temperature of the battery;
By selectively depriving latent heat of vaporization only from high-temperature batteries,
It is also possible to arbitrarily change and embody the configuration of each part without departing from the spirit of the present invention, such as by employing other configurations as the stirring means and pressure feeding means in the fire extinguishing device.

[0024]

[Effects of the Invention] Since the present invention is constructed as described above, it achieves the following excellent effects. In the invention of the fire extinguishing method of claim 1, when a fire occurs in a sodium-sulfur battery, a slurry-like fire extinguishing agent mixed with an inert liquid and a granular fire extinguishing agent is pumped into the battery case, so that there is no abnormality in the battery. Fires inside batteries can be quickly and reliably extinguished by suppressing reactions.

Further, in the invention of the fire extinguishing device according to claim 2, the inert liquid and the granular fire extinguishing agent are stirred in the tank by the stirring means to create a slurry fire extinguishing agent, and the slurry fire extinguishing agent is transferred to the battery by the pressure feeding means. Since the configuration is such that the granular fire extinguishing agent Sa is mixed and stirred with the inert liquid L to form a fluid slurry, it can be smoothly fed into the case without stagnation in pipes, etc. and can be supplied quickly.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of a fire extinguishing device for a sodium-sulfur battery embodying the present invention.

FIG. 2 is a perspective view of the fire extinguishing device.

FIG. 3 is an enlarged cross-sectional view of the battery case.

[Explanation of symbols]

1 case, 5 battery, 9 supply pipe, 11
Storage tank, 12 Gas cylinder as stirring means,
16 Pump as pressure feeding means, S slurry fire extinguishing agent, L inert liquid, Sa granular fire extinguishing agent.

Claims (2)

[Claims] Claim 1: A fire in a sodium-sulfur battery, characterized in that a slurry extinguishing agent, which is a mixture of an inert liquid and a granular extinguishing agent, is supplied under pressure into a case housing an assembled battery consisting of a sodium-sulfur battery. fire extinguishing method. Claim 2: An assembly comprising a tank containing an inert liquid and granular fire extinguishing agent, a stirring means for stirring the inert liquid and granular fire extinguishing agent in the tank to create a slurry fire extinguishing agent, and a sodium-sulfur battery. Inside the case containing the battery,
A fire extinguishing device for a sodium-sulfur battery, characterized in that it is provided with a pumping means for pumping and supplying a slurry fire extinguishing agent from the tank.