JPH03112568A - Extinguishing method for fire of sodium-surfur battery - Google Patents

Abstract

PURPOSE:To rapidly extinguish the fire of a sodium-sulfur battery by a method wherein oil having a high flash point higher than the melting temperature of the active material of the battery and nonreactivity against the active material and a product produced during the occurrence of a fire and insulating properties is injected in a case containing the battery. CONSTITUTION:When an abnormal even is detected by, for example, a heat sensor and a gas sensor in a case 2, a control device closes an inflow pipe 9a and a discharge pipe 9b to stop the circulation of air and stop heating effected by an electric heater 6. An outflow pipe 8 is opened and an injection pipe 7 is opened to inject silicone oil 3 from a position below the case 2, and an injection pipe 10 is opened to jet in nitrogen gas G. In which case, since the silicone oil 3 has high heat capacity, metallic sodium, surfur, and sodium polysulfide flowing in the case 2 are rapidly cooled for coagulation. Meanwhile, the silicone oil 3 does never chemically react to metallic sodium and surfur, and since the flash point of the silicone oil 3 is higher than the melting temperatures of metallic sodium and surfur, the silicone oil 3 is prevented from taking fire.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for extinguishing a fire in a sodium-sulfur battery, and more specifically, a fire extinguishing method for extinguishing a fire in a sodium-sulfur battery due to a chemical reaction of the active material inside the battery. This relates to methods for extinguishing fires.

[Prior Art] Recently, secondary batteries for electric vehicles and nighttime power storage have been developed that are excellent in both performance and economical aspects, and
Research and development of high-temperature sodium-sulfur batteries that operate at ℃ is progressing.

In other words, in terms of performance, sodium-sulfur batteries have a higher theoretical energy density than lead-acid batteries, do not generate hydrogen or oxygen during charging and discharging, and have a high utilization rate of the positive electrode active material, and are economically superior to metals. Sodium and sulfur have the advantage of being cheap. This sodium-
Multiple sulfur batteries are connected in series, and then multiple sulfur batteries are placed in series. Then, by heating the battery group arranged in this way to 300 to 400 degrees Celsius with a heater, the metals such as lithium and sulfur that become the active materials are melted, and the ions of the active materials are transferred to the molten state. Let's electrify each other? A reaction is carried out to obtain a predetermined amount of electrical energy.

[Problem to be solved by the invention] However, due to some circumstances such as an overcurrent flowing through the sodium-sulfur battery due to an accidental short-circuit current, etc., the solid electrolyte tube inside the sodium-sulfur battery may be destroyed. . , = In the case of destruction, the molten metal sulfur and sulfur, which were separated into the inside and outside by the solid electrolyte tube, come into direct contact and mix, causing a chemical reaction. The heat of reaction causes a fire to occur within the case. In this case, it is not appropriate to use water as a fire extinguishing agent because metallic sodium reacts violently with water.

An object of the present invention is to provide a method for extinguishing a fire in a sodium-sulfur battery, which can quickly extinguish a fire in a sodium-sulfur battery.

[Solve the problem! In order to achieve the object set forth in F, the first invention of the present application is: 1. Contains a sodium-sulfur battery; , has a high flash point L7 higher than the melting temperature of the active material of the battery, has non-reactivity with the active material and products in the event of a fire, and
Fill with insulating oil. 'l-, is its gist.

In a second aspect of the invention, the oil is injected into the case from below L20, the oil is injected into the case at a predetermined NJ, 1. The gist is that when L is stored, 4- flows out from the top of the case.

The gist of the third invention is that the oil is injected into the case and an inert gas is also injected into the case.

[Function] When oil is injected into the case using the J structure acid, the molten sulfur, metal sodium 11, and sulfur and lithium polysulfides are cooled by the inflowing oil to a temperature below their respective melting points and solidified. Becomes a solid. Solidified sulfur and sodium polysulfide lack reactivity and are inactivated6. On the other hand, metallic sodium is covered with oil and is prevented from reacting with oxygen in the air. Furthermore, oil does not react with metallic sodium, sulfur, etc.

Moreover, in claim 2, the oil injected from the bottom of the case cools the metal sodium and sulfur, and then flows out from the top of the case.

Furthermore, in claim 3, when inert gas is injected into the case, the inert gas discharges the air inside the case to the outside of the tooth, thereby suppressing the chemical reaction between oxygen in the air and metal sodium and sulfur.

[Example] Hereinafter, an example embodying the present invention will be described based on the drawings.6 As shown in Figure 1, the case 2 is formed in a square box shape and has a double wall structure inside and outside. A heat insulating material 1 is interposed between the inner and outer walls. A mounting table 4 is disposed at the bottom of the case 2 via a support member 11, and a plurality of battery packs 5 are erected on the mounting table 4. Although not shown in the drawings, each battery pack 5 has single sodium-sulfur batteries vertically stacked and connected in series. In a single thorium-sulfur battery, metal sulfur and sulfur are separately housed through a solid electrolyte tube. Reference numeral 6 denotes an electric heater provided at the bottom of the mounting table 4 and the game device 2, which heats the temperature inside the case 2 to about 320° C. and melts the metal sodium and sulfur inside the battery pack 5. .

In Fig. 1, the injection pipe 7 is located on the lower left side of the case 2.
is installed through the case 1 on the right side 1. An outflow pipe 8 is provided through the side.

This outflow pipe 8 is provided at a position sufficiently higher than the height of the battery pack 5.

And, on the upper left side of the case 2, a pair of pipes 9a,
9b is provided through it. The pipe 9a on the - side is an inflow pipe 9a through which external air flows in, and the other pipe 91) is an exhaust pipe 9b through which air inside the case 2 is discharged. The temperature inside the gate 2 is maintained at about 320 DEG C. by circulating air through the pipes 9a and 9b and by controlling the temperature of the electric heater 6. Furthermore, an injection pipe 10 for injecting dry inert gas G is installed through the upper left side of the case 2.

Next, the characteristics and type of the oil 3 injected into the case 2 through the injection pipe 7 will be explained.

The melting temperature of metallic sodium in the sodium-sulfur battery constituting the battery assembly 5 is approximately 98°C, and the melting temperature of sulfur is 1
Since the temperature is 19°C, the flash point temperature of the oil 3 is set to be 120°C or higher. Furthermore, in order to improve fluidity, oil 3 with low viscosity is used. Then, the adjacent battery pack 5
In order to prevent the oil 3 from short-circuiting them, a volume specific resistivity of 109ΩC11 or more is suitable.

Here, even in the solidified state, metallic sodium is hydrogen fluoride (HF), hydrogen chloride (HCj), and sulfide.

Hydrogen (Has), hydrogen (H), bromine (Br), fluorine (
F), chlorine (Cj), sulfur (S), mercury (Hg), water (
It is necessary to select an oil 3 that does not contain substances that are reactive with metallic sodium.

Furthermore, it is necessary to select an oil 3 that does not contain substances that react with sulfur.

Also, the reactants produced based on metallic sodium and sulfur, sulfur dioxide (SOW), sodium hydroxide (NaOH), sodium hydride (Na20), sodium peroxide (Na20x), sodium sulfide (Na2
sow), carbon disulfide (C8z), nitrogen oxides (N
Ox), etc.

Therefore, it is necessary to select an oil 3 that does not react with the above-mentioned reactants.

Therefore, examples of the oil 3 that satisfies the above conditions include the following.

Suitable electrical insulating oils include mineral oil, alkylbenzene, polybutene, alkylnaphthalene, alkyldiphenylethane, silicone oil, and a mixture of mineral oil and alkylbenzene. In addition, vegetable oils such as rapeseed oil are also suitable.

Further, a dry inert gas G is injected into the case 2, and suitable types of the inert gas G include helium, neon, argon gas, nitrogen gas, and the like.

In this embodiment, silicone oil is used as the oil 3 and has a specific gravity that is substantially the same as that of metallic sodium, and nitrogen gas is used as the inert gas G.

Next, a method of extinguishing a fire in a sodium-sulfur battery will be explained.

When the inside of the case 2 is maintained at about 320° C., the metal sodium and sulfur of the sodium-sulfur battery constituting the battery pack 5 are in a molten state.

If the solid electrolyte tube of the sodium-sulfur battery constituting the battery assembly 5 is damaged for some reason, the molten metal sodium in the solid electrolyte tube will come into direct contact with and mix with the molten sulfur in the anode container. It turns out. Then, the following chemical reaction takes place as the main reaction, producing sodium polysulfide, especially disodium sulfide.

2 Na1X S-N a2 S x At this time, a large amount of chemical reaction heat is generated, the case of the battery pack 5 is thermally destroyed, and metallic sodium and sulfur flow into the case 2.

Then, the metal sodium further reacts with oxygen, water, etc. in the air, becomes high temperature, and destroys the other battery packs 5.

Therefore, when a sensor (not shown) inside the case 2, such as a heat sensor or a gas sensor that detects gas in the event of a fire, detects this abnormal situation, the control device controls the inflow pipe 9a,
The exhaust pipe 9b is closed to stop air circulation, and the electric heater 6 stops heating. Then, the outflow pipe 8 is opened, and the injection pipe 7 is opened to inject the silicone oil 3 from below the case 2, and the injection pipe 110 is opened to inject the nitrogen gas G.

Then, since the silicone oil 3 has a large heat capacity, it quickly cools the metal sodium, sulfur, and sodium polysulfide that have leaked into the case 2. This removes heat from the sulfur and sodium polysulfide and solidifies them, stopping the chemical reaction and turning them into chemically safe substances. On the other hand, metallic sodium also loses heat and solidifies. In addition, since the entire metal layer is immersed in the silicone oil 3, water and oxygen are blocked and the reaction is stopped. On the other hand, there is no chemical reaction between silicone oil 3 and metal 1-lium, and between silicone oil 3 and sulfur, and the flash point of silicone oil 3 is
・Because it is higher than the melting temperature of sulfur, silicone oil 3 will not catch fire.

When the level of the silicone oil 3 reaches the outflow pipe 8 of the gas 2, it is stored in a discharge tank (not shown) via the outflow pipe 8. Therefore, the silicone oil 3 is not discharged from the inside of the woofer 2 to a high temperature, and the metals sulfur, lithium, and sulfur can be efficiently cooled.

In addition, the air inside the case 2 is discharged from the outflow pipe 8 by the 9-element gas G injected from the upper part of the case 2.
- Space 2 is filled with nitrogen gas. As a result, since the specific gravity of the silicone oil 3 and the specific gravity of the metal sulfur and lithium are approximately the same, even if the metal satorium reaches the liquid level of the silicone oil 3,
7, metallic sodium does not react with nitrogen gas.

Furthermore, since the silicone oil 3 is a low viscosity oil 1, the battery pack 5 is placed on the raft M (.
- Can be easily injected into the tank 2 and quickly
The fire inside the space 2 can be extinguished.

Note that this invention is not limited to the above-mentioned practical example (:'':T!l), and may be arbitrarily modified without departing from the gist of the invention in Section 5.2.

[Effects of the Invention] As described above in detail 1 and 2, according to the present invention, by injecting oil into the case, the heat of the metal strium, sulfur, and 1-lium polysulfide is stimulated, and the air is Reactions with oxygen and water inside can be suppressed, and since there is no chemical reaction with oil, safety is improved, and fires in collective batteries can be quickly extinguished.

In addition, when the oil injected from below the case accumulates in excess of a predetermined amount within the case, the oil will flow out from one side of the case, making it possible to efficiently cool the metal sodium and sulfur and quickly extinguish the fire. effective.

Furthermore, by filling the case with inert gas,
Since it prevents metal sodium and sulfur from reacting with oxygen and water in the air, it has the effect of reliably preventing metal sodium from causing a chemical reaction with oxygen again during fire extinguishing work.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of the inside of a case in which an assembled battery is housed, and FIG. 2 is an explanatory diagram showing a state in which silicone oil is injected into the case to fill the inside of the case. 2... Case, 3... Oil, 5... Collective battery, G.
...Inert gas.

Claims (1)

[Scope of Claims] 1. A case containing a group of assembled batteries constituted by sodium-sulfur batteries has a high flash point higher than the melting temperature of the active material of the battery, and has a high flash point that is higher than the melting temperature of the active material of the battery. A method for extinguishing a fire in a sodium-sulfur battery, characterized by injecting oil that is non-reactive with the generated products and has insulating properties. 2. Inject the oil into the case from below,
2. The method of extinguishing a fire in a sodium-sulfur battery according to claim 1, wherein the oil flows out from above the case when a predetermined amount or more of the oil is stored in the case. 3. The method for extinguishing a fire in a sodium-sulfur battery according to claim 1 or 2, characterized in that the oil is injected into the case and an inert gas is also injected into the case.