JPH09330738A - Sodium-sulfur battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakage of a cell and enhance the cell life by lowering the temperature of the cell in the state where the temperature of the cell upper part is regularly lower than the lower part, when the cell temperature is lowered, so as to solidifying positive and negative electrode active materials from the cell upper part toward the lower part. SOLUTION: In a module vessel 11, cells 10 are housed within cell covers 12, and the adjacent covers 12 are mutually connected by a cell cover connecting plate 18. The vessel 11 has a fluid temperature control device 16 for the heating and cooling necessary for temperature rise and fall of the cells, and an inlet pipe 14 for introducing a heating and cooling fluid 8 into the vessel 11 and an exhaust pipe 15 for exhausting it are set on the upper part of the vessel 11. A periodic inspection requires to lower the temperature from steady operating temperature to room temperature. Since the cooling fluid 8 is then carried on the upper part of the vessel 11, the cell 10 is gradually cooled from the upper part to the lower part. Since the positive and negative active materials are thus solidified from the cell upper part to the lower part within the battery 10, the density is roughed to produce holes, so that no stress acts on each cell component to transformation expansion, particularly, after solidification of sulfur of the positive electrode active material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sodium-sulfur battery module, and more particularly to a sodium-sulfur battery module most suitable for reducing the stress generated in the battery during temperature lowering and temperature raising and improving the reliability of strength of the battery.

[0002]

2. Description of the Related Art Many proposals have been made in the past regarding heating and cooling methods for sodium-sulfur battery modules. For example, in Japanese Unexamined Patent Publication (Kokai) No. 2-256174, when the battery storage cases are brought into surface contact with each other and integrally connected, heat conduction is uniformly performed by surface contact when heating and cooling the battery. The temperature distribution of is uniformed. Further, Japanese Patent Application Laid-Open No. 58-25088 is devised so that a space is provided between holding members for holding the cells and all the side surfaces of the cells are air-cooled to uniformly cool the cells. Further, JP-A-49-21629 is devised so that when the cell is heated and heated, sodium as a negative electrode active material and sulfur as a positive electrode active material are melted from the upper part to the lower part of the battery.

[0003]

As described above, in the conventional sodium-sulfur battery module, a device for reducing and making uniform the temperature distribution in the unit cell and the temperature distribution between the cells at the time of heating and cooling. Also, while sodium of the negative electrode active material is melted by heating the sulfur of the positive electrode active material at elevated temperature, it is devised from the viewpoint of reducing the stress generated by melting from the upper part to the lower part. It is considered from the viewpoint of solidifying sodium of the negative electrode active material and sulfur of the positive electrode active material toward the lower part, and particularly reducing the stress generated by transformation expansion that occurs after solidification of the positive electrode active material and increasing the battery life. There wasn't.

[0004]

In order to achieve the above object, a first aspect of the present invention is to shrink a large number of sodium-sulfur batteries in which a plurality of cells each having a pair of positive electrode terminals and negative electrode terminals are connected in series and parallel to each other. -In the module of the sulfur battery, when the temperature of the battery is lowered, the sodium of the negative electrode active material and the sulfur of the positive electrode active material are solidified from the upper part to the lower part of the battery,
A sodium-sulfur battery module having a structure characterized in that means for constantly lowering the temperature of the upper part of the battery than the lower part of the battery is installed.

A second aspect of the invention is to exhaust heat and exhaust only from the upper part of the battery as means for solidifying the sodium of the negative electrode active material and the sulfur of the positive electrode active material from the upper part to the lower part of the battery when the temperature of the battery is lowered. It is a sodium-sulfur battery module having a characteristic structure.

A third aspect of the invention is a means for solidifying sodium as a negative electrode active material and sulfur as a positive electrode active material from the upper part to the lower part of the battery when the temperature of the battery is lowered, and the entire battery is cooled while heating the lower part of the battery when the temperature of the battery is lowered. It is a sodium-sulfur battery module having a structure characterized by

According to the first to third inventions, since sodium of the negative electrode active material and sulfur of the positive electrode active material solidify from the upper part to the lower part of the battery when the temperature of the battery is lowered, both active materials are contracted during solidification cooling. It solidifies from the top while the density becomes coarse. In particular, in the case of sulfur, stress does not act on each component of the battery even with respect to volume expansion due to transformation after solidification, which prevents damage to the battery and increases battery life. In the sodium of the negative electrode active material and the sulfur of the positive electrode active material that have undergone the solidification process even after reheating after solidification, even if volume expansion due to melting and heat transformation occurs during heating at elevated temperature, the pressure increase is caused in each active material. Can be absorbed by and can prevent stress from acting on each part of the battery. Therefore, it is possible to prevent damage to the battery and increase the battery life.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the sodium-sulfur battery module of the present invention is shown in FIG. In a sodium-sulfur battery module container 11 for storing a large number of sodium-sulfur batteries, each of which has a pair of positive electrode terminals 1 and negative electrode terminals 2 connected in series and in parallel, each of the single cells 10 is attached to a battery cover 12. The battery cover 12 connects the adjacent battery covers 12 with each other by the battery cover connecting plate 18. Fireproof sand 13 is provided between the connecting covers 12. The sodium-sulfur battery module has a fluid temperature control device 16 for heating and cooling necessary for raising and lowering the temperature of the battery, and supplies the heating and cooling fluid 8 to the module container 1
1, the introduction pipe 14 drawn into the upper part of the module container 11,
A discharge pipe 15 for exhausting the heating and cooling fluid 8 is also installed above the module container 11. In FIG. 1, it is necessary to lower the temperature from the steady operating temperature to room temperature at the time of regular inspection. At that time, in the structure of the present invention, the cooling fluid 8 flows in the upper part of the battery module container 11 from the introduction pipe 14 to the discharge pipe 15, so that the battery 10 is cooled from the upper part to the lower part. In the inside of the unit cell 10 at that time, as shown in FIG. 2, since sodium of the negative electrode active material 5 and sulfur of the positive electrode active material 6 solidify from the upper part of the battery toward the lower part of the battery,
Both active materials 5 and 6 have a coarse density due to shrinkage during solidification and cooling, and voids 9 are generated in the solid negative electrode active material 5-2 and the solid positive electrode active material 6-2 due to shrinkage. The stress does not act on each component of the battery due to the transformation expansion after solidification. The positive and negative active materials 6 and 5 of sodium and sulfur that have undergone the solidification process do not exert stress on the various components of the battery even when they are subjected to thermal expansion and transformation expansion due to reheating after solidification, preventing damage to the battery and improving battery life. Has the effect of increasing.

FIG. 3 shows an embodiment of the present invention. The battery module container 11 has a vacuum 17 heat insulating structure, and the upper lid 22 also has a vacuum 17 heat insulating structure. During heating, heating is performed by the upper heater 7-1, and during steady operation, the side heater 7-2 maintains a constant temperature. When the temperature is decreased from the steady operating temperature to room temperature, all the heaters 7-1 and 7-2 in the module container 11 are turned off to naturally cool.
The heat is radiated only from the heat sealing plate 24 between the module container 11 and the upper lid 22, which is not a vacuum heat insulating unit, so that the battery is cooled from the upper portion toward the lower portion. That is, since sodium of the negative electrode active material 5 and sulfur of the positive electrode active material 6 solidify from the upper part to the lower part of the battery, stress is generated in each part of the battery structure caused by thermal expansion of reheating after solidification and volume expansion due to transformation. It has the effects of reducing the amount, preventing damage to the battery, and increasing the battery life. The present invention has a simple structure in which the fluid temperature control device shown in FIG. 1 is unnecessary.

4 and 5 show another embodiment of the present invention.
At the time of heating and operation, as shown in FIG. 4, the upper movable cover 20 is pushed until it contacts the stopper 19 to prevent heat radiation, and when the battery cooling temperature is lowered, the movable cover 20 is pulled as shown in FIG. By appropriately opening and discharging heat, sodium in the negative electrode active material 5 and sulfur in the positive electrode active material 6 are solidified from the upper part to the lower part of the battery when the temperature is lowered. Also in this embodiment, similarly to the invention shown in FIGS. 1 and 3, transformation due to sulfur after solidification, thermal expansion at the time of reheating and stress generation in each part of the battery structure due to transformation expansion are reduced, and damage to the battery is prevented. Along with this, the battery life is increased. In this embodiment, the fluid temperature control device 16 as shown in FIG. 1, the vacuum heat insulating container 11 and the vacuum heat insulating upper lid 22 as shown in FIG. 3 are unnecessary, and the structure is extremely simple.

FIG. 6 shows a modified application example of the present invention. A heater 7-3 is installed in the lower part of the battery module structure, and as the means for solidifying sodium of the negative electrode active material 5 and sulfur of the positive electrode active material 6 from the upper part to the lower part of the battery when the battery temperature is decreased, the battery temperature decrease is performed. Sometimes the lower part of the battery is heated by a heater 7-3
The temperature of the entire battery can be lowered while heating. This battery module structure also has the effects of reducing stress generation in various parts of the battery structure, preventing damage to the battery, and increasing battery life. According to the present invention, it is possible to more reliably lower the temperature of the entire battery while making the temperature of the lower portion of the battery higher than that of the upper portion thereof, as compared with the inventions of FIGS. 1 and 3, 4 and 5.

[0012]

According to the present invention, the stress generated in each part of the battery is reduced, damage to the battery is prevented, and the battery life is increased.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a solidification state of positive and negative electrode active materials in a unit cell.

FIG. 3 is an explanatory view of another embodiment of the present invention.

FIG. 4 is an explanatory diagram of another embodiment of the present invention.

FIG. 5 is an explanatory view of another embodiment of the present invention.

FIG. 6 is an explanatory diagram of an application modification example of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Positive electrode terminal, 2 ... Negative electrode terminal, 3 ... Insulating ring, 4 ... Solid electrolyte tube, 5 ... Negative electrode active material, 5-1 ... Liquid negative electrode active material, 5-2 ... Solid negative electrode active material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisamitsu Hato 3-1-1, Saiwai-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Tadahiko Miyoshi 3-chome, Hitachi-shi, Ibaraki No. 1 No. 1 Stock Company Hitachi Ltd. Hitachi factory

Claims (3)

[Claims] 1. A sodium-sulfur battery module containing a large number of sodium-sulfur batteries, each of which has a pair of positive and negative terminals connected in series and in parallel, in a sodium-sulfur battery module from the upper part to the lower part of the battery when the temperature of the battery is lowered. A sodium-sulfur battery module, characterized in that means for constantly cooling the upper part of the battery at a lower temperature than the lower part of the battery is installed so that sodium of the negative electrode active material and sulfur of the positive electrode active material solidify. 2. The method according to claim 1, wherein as the means for solidifying the sodium of the negative electrode active material and the sulfur of the positive electrode active material from the upper part to the lower part of the battery when the temperature of the battery is lowered, the exhaust heat and exhaust gas from only the upper part of the battery are used. Sulfur battery module. 3. The battery according to claim 1, wherein as the means for solidifying the sodium of the negative electrode active material and the sulfur of the positive electrode active material from the upper part to the lower part of the battery when the temperature of the battery is lowered, the battery is heated while the lower part of the battery is heated. Sodium-sulfur battery module that cools the whole.