JP2011228211A - Molten-salt battery and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molten-salt battery having an enlarged electrode using sodium as an active material, and to provide a method of manufacturing the same.SOLUTION: The molten-salt battery has a negative electrode 1 which is obtained by forming a sodium film 12 on a metal substrate 11, or by forming a base film 13 exhibiting good wettability to molten metallic sodium on the substrate 11 and then forming the sodium film 12 on the base film 13. The negative electrode 1 is produced by immersing the substrate 11 on which the base film 13 is formed or not formed into molten metallic sodium. The negative electrode 1 has high strength as compared with an electrode formed of metallic sodium, and since the facility required for producing the electrode is simplified, the negative electrode 1 can be enlarged.

Description

  The present invention relates to a molten salt battery using sodium as an active material of an electrode, and a method for manufacturing a molten salt battery.

  In recent years, utilization of natural energy such as sunlight or wind power has been promoted. When power generation is performed using natural energy, the power generation amount is likely to fluctuate due to changes in natural conditions such as the weather, and it is difficult to adjust the power generation amount according to the power demand. Therefore, in order to supply electric power generated using natural energy, it is necessary to level the supplied electric power by charging / discharging using a storage battery. For this reason, in order to further promote the use of natural energy, a storage battery with high energy density and high efficiency is indispensable. As such a storage battery, there is a sodium-sulfur battery disclosed in Patent Document 1. The sodium-sulfur battery is a battery using molten sodium as an active material, and the internal temperature is a high temperature exceeding the melting point of sodium (about 98 ° C.). A sodium-sulfur battery is manufactured by enclosing metallic sodium in a container, and then operates as a battery after the internal temperature is raised to dissolve the metallic sodium.

JP-A-2-040866

Addison, Iberson and Manning, "Liquid Metals. Part V. The Role of Oxide Films in the Wetting of Iron, Cobalt, and Nickel by Liquid Sodium, and by Solutions of Barium and Calcium in Liquid Sodium.", J. Chem. Soc ., 1962, 2699. Addison and Iberson, "Liquid Metals. Part XI. The Wetting of Chromium, Molybdenum, and Tungsten by Liquid Sodium.", J. Chem. Soc., 1965, 1437.

  Since the sodium-sulfur battery needs to be operated at a high temperature exceeding the melting point of sodium, there is a problem that it takes time to raise the internal temperature when used. Moreover, since sodium in a molten state has high reactivity, there is a problem that sodium-sulfur batteries have low safety. On the other hand, a molten salt battery using molten salt that melts at a temperature lower than the melting point of sodium as an electrolyte and using unmelted sodium as an active material has attracted attention. In such a molten salt battery, since the operating temperature is lower than that of the sodium-sulfur battery, the time required for the temperature rise is shortened and the safety is improved.

In the molten salt battery, the capacity density can be maximized when one of the electrodes is metallic sodium. However, since metallic sodium is soft, an electrode made by processing metallic sodium becomes more fragile as it becomes larger. Moreover, since metallic sodium is highly reactive and it is dangerous to process metallic sodium in the atmosphere, it is necessary to perform the work of processing metallic sodium in a glove box with an adjusted atmosphere. Although it is possible to manually produce a small sodium electrode in the glove box, it is difficult to produce a large sodium electrode by machining that requires equipment such as a roll press. For these reasons, there is a problem that it is difficult to produce a large sodium electrode that can be used in a practical molten salt battery.
The present invention has been made in view of such circumstances, and an object thereof is to provide a molten salt battery in which an electrode using sodium as an active material is enlarged by forming an electrode with a sodium film, and It is providing the manufacturing method of a molten salt battery.

  The molten salt battery according to the present invention is a molten salt battery using sodium as an active material of an electrode, wherein the electrode is formed by coating a metal base material with a sodium film.

  In the molten salt battery according to the present invention, a base film serving as a base for the sodium film is formed on the base material using a metal having better wettability of molten metal sodium than the base material. The sodium film is formed on the substrate.

  The molten salt battery according to the present invention is characterized in that the material of the base film is iron, tungsten, chromium or molybdenum.

  The molten salt battery according to the present invention is characterized in that the material of the base film is nickel or cobalt.

  The molten salt battery according to the present invention is characterized in that the main material of the substrate is nickel.

  The molten salt battery according to the present invention is characterized in that the main material of the substrate is aluminum.

  The method for producing a molten salt battery according to the present invention is a method for producing a molten salt battery using sodium as an active material of an electrode, wherein the substrate is obtained by immersing a metal substrate in molten metal sodium. A molten salt battery is manufactured by coating with a sodium film and using the substrate coated with a sodium film as one electrode.

  The manufacturing method of the molten salt battery according to the present invention is a method in which the base metal is immersed in molten metal sodium, the metal having a better wettability of the molten metal sodium than the base material, and the sodium A base film serving as a base of the film is formed, and the temperature of molten metal sodium is adjusted to be equal to or higher than a temperature at which the components of the base film react with sodium.

  In the method for manufacturing a molten salt battery according to the present invention, the base material is formed in a flat plate shape, a temperature gradient is generated in the molten metal sodium, and the base material is oriented in a direction in which the temperature changes in the thickness direction. It is characterized by being immersed in molten metal sodium.

  In the present invention, the molten salt battery includes an electrode in which a metal base material is immersed in molten metal sodium to coat the base material with a sodium film. Compared to forming the electrode with metallic sodium, the strength of the electrode is increased, and the equipment required for manufacturing the electrode is simplified.

  In the present invention, an electrode for a molten salt battery is manufactured by forming a base film on a base material with a metal having better wettability of molten metal sodium than the base material, and forming a sodium film on the base film. . Compared to forming a sodium film directly on the substrate, the sodium film is formed at a low temperature or in a short time.

  In the present invention, the base film is made of iron, tungsten, chromium, or molybdenum, so that the sodium film can be formed at a low temperature or in a short time.

  In the present invention, by using nickel or cobalt as the base film material, a sodium film can be formed even when a base material having low reactivity with respect to sodium is used.

  Moreover, in this invention, the tolerance with respect to the electrolyte of an electrode becomes high by making the material of the base material of an electrode into nickel.

  Moreover, in this invention, an electrode is reduced in weight by making the material of the base material of an electrode into aluminum.

  Moreover, in this invention, a sodium film is formed in the single side | surface of a base material by immersing a flat base material in the molten metal sodium which has a temperature gradient.

  In the present invention, the electrode of the molten salt battery has higher strength and can be made larger than an electrode formed of metallic sodium. Also, the equipment necessary for manufacturing the electrode becomes simpler, and it becomes easier to enlarge the electrode. Therefore, the present invention has excellent effects, such as the realization of a practical molten salt battery in which an electrode using sodium as the active material of the electrode is enlarged.

It is a typical exploded sectional view showing an example of composition of a molten salt battery concerning Embodiment 1 of the present invention. 2 is a schematic cross-sectional view of a negative electrode of a molten salt battery according to Embodiment 1. FIG. It is typical sectional drawing which shows the method of forming a sodium film | membrane. It is a characteristic view which shows the relationship between the temperature of molten metal sodium, and the immersion time of the base material until a sodium film is formed. 6 is a schematic cross-sectional view of a negative electrode of a molten salt battery according to Embodiment 2. FIG.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
(Embodiment 1)
FIG. 1 is a schematic exploded cross-sectional view showing a configuration example of a molten salt battery according to Embodiment 1 of the present invention. The molten salt battery is configured such that a positive electrode 2, a separator 3, and a negative electrode 1 are stacked in a box-shaped battery container 41 whose upper surface is open, and a lid 42 is attached to the battery container 41. The positive electrode 2 and the negative electrode 1 are formed in a rectangular flat plate shape, and the separator 3 is formed in a sheet shape. The separator 3 is interposed between the positive electrode 2 and the negative electrode 1, and the positive electrode 2, the separator 3, and the negative electrode 1 are arranged so that the positive electrode 2 is located on the bottom side of the battery container 41.

The positive electrode 2 is formed by applying a positive electrode material 22 including a positive electrode active material such as NaCrO ₂ and a binder on a rectangular plate-shaped positive electrode current collector 21 made of aluminum. The positive electrode active material is not limited to NaCrO ₂ , and may be other metals or metal compounds, or may be a non-metallic material such as sulfur. The positive electrode current collector 21 is not limited to aluminum, and may be stainless steel, for example. The separator 3 is formed of an insulating material such as glass cloth so that the electrolyte can be held inside. The separator 3 is impregnated with a molten salt that is an electrolyte. In the present embodiment, a molten salt composed of FSI (bisfluorosulfonylimide) or TFSI (bistrifluoromethylsulfonylimide) anion and sodium and / or potassium cations is used as the electrolyte. This molten salt is a molten salt that melts at 80 ° C. or higher, which is lower than the melting point of sodium.

  FIG. 2 is a schematic cross-sectional view of negative electrode 1 of the molten salt battery according to Embodiment 1. The negative electrode 1 has a configuration in which a metal base 11 formed in a rectangular plate shape is covered with a sodium film 12. The sodium film 12 is formed with sodium as a negative electrode active material as a main component. The sodium film 12 is made of metallic sodium and may contain a compound of sodium and another substance. The thickness of the sodium film 12 is 20 μm to 100 μm. The thickness of the sodium film 12 is related to the capacity of the molten salt battery. In order to secure the minimum capacity in the molten salt battery, the thickness of the sodium film 12 needs to be 20 μm or more.

  The substrate 11 serves as a negative electrode current collector. The material of the base material 11 is nickel, cobalt, iron, tungsten, chromium, or molybdenum. These metals are metals having the wettability of molten metal sodium. Among these metals, nickel is most resistant to the molten salt that is an electrolyte, and hardly dissolves into the molten salt during charging and discharging of the molten salt battery. For this reason, when nickel is used as the material of the base material 11, when the molten salt battery is repeatedly charged and discharged, the negative electrode 1 is hardly deteriorated, and the life of the molten salt battery is maximized. Therefore, it is desirable that the material of the base material 11 is nickel from the viewpoint of the life of the molten salt battery. In addition, the base material 11 does not need to be formed of a single metal, and may be formed of an alloy of nickel, cobalt, iron, tungsten, chromium, or molybdenum, and includes a compound with another substance. Also good.

  The sodium film 12 is formed by immersing the base material 11 in molten metal sodium. FIG. 3 is a schematic cross-sectional view showing a method for forming the sodium film 12. A reaction vessel 52 formed of a heat-resistant material such as heat-resistant glass is placed on a flat heater 53 such as a hot plate, and metallic sodium is put into the reaction vessel 52. By heating the metallic sodium in the reaction vessel 5 with the heater 53, the metallic sodium melts at 98 ° C. or higher to become molten metallic sodium 51. A temperature control unit (not shown) is connected to the heater 53, and the heater 53 adjusts the temperature of the molten metal sodium 51 in the reaction vessel 52. By heating the molten metal sodium 51 with the heater 53 on which the reaction vessel 52 is placed, a temperature gradient is generated in the molten metal sodium 51 such that the lower side is high and the upper side is low. The rectangular plate-shaped base material 11 is immersed in the molten metal sodium 51 in such a direction that the direction in which the temperature changes due to the temperature gradient becomes the thickness direction. The base material 11 is immersed after being gripped by a gripping tool (not shown), or is immersed in a part of a rectangular flat plate of a member bent in an L shape in a side view as the base material 11. Then, it is immersed in the molten metal sodium 51. The above operations are performed in a glove box with an adjusted atmosphere.

The reactivity of nickel, cobalt and iron to sodium is described in Non-Patent Document 1, and the reactivity of tungsten, chromium and molybdenum to sodium is described in Non-Patent Document 2. These metals react with sodium at a temperature equal to or higher than the wetting temperature specific to each metal, and the wettability of the molten metal sodium 51 is improved. That is, a compound is formed at the interface between the base material 11 and the molten metal sodium 51 at a specific temperature or higher according to the material of the base material 11, and the wettability between the base material 11 and the molten metal sodium 51 is improved. The molten metal sodium 51 adheres to the base material 11 to form the sodium film 12. For example, when the material of the base material 11 is tungsten, Na ₂ WO ₄ is generated at the interface between the base material 11 and the molten metal sodium 51 at 160 ° C. or higher, and the sodium film 12 is further formed. The higher the temperature of the molten metal sodium 51, the higher the rate at which the sodium film 12 is formed. Since a temperature gradient in the thickness direction of the base material 11 is generated in the molten metal sodium 51, the sodium film 12 is formed on the surface of the base material 11 where the temperature is higher. In the example shown in FIG. 3, the sodium film 12 is formed on the lower surface of the base material 11. Further, the higher the temperature of the molten metal sodium 51, the shorter the immersion time, which is the time during which the substrate 11 is immersed in the molten metal sodium 51 until the sodium film 12 having a thickness of 20 μm or more is formed.

  FIG. 4 is a characteristic diagram showing the relationship between the temperature of the molten metal sodium 51 and the immersion time of the base material 11 until the sodium film 12 is formed. FIG. 4 shows the experimental results when the material of the base material 11 is nickel, tungsten, or molybdenum. The sodium film 12 is not formed on the base material 11 made of tungsten or molybdenum at a temperature lower than 160 ° C. When the material of the base material 11 is tungsten, the immersion time until the sodium film 12 having a thickness of 20 μm or more is formed is 100 minutes at 160 ° C., 60 minutes at 180 ° C., 30 minutes at 200 ° C., and 220 ° C. It was 15 minutes. Further, when the material of the base material 11 is molybdenum, the immersion time until the sodium film 12 having a thickness of 20 μm or more is formed is 90 minutes at 160 ° C., 45 minutes at 180 ° C., 25 minutes at 200 ° C., 220 It was 15 minutes at ° C. Even when the material of the base material 11 is chromium, the sodium film 12 is formed at substantially the same temperature and time as tungsten or molybdenum. Further, the sodium film 12 is not formed on the base material 11 made of nickel at a temperature lower than 195 ° C. When the material of the substrate 11 is nickel, the immersion time until the sodium film 12 having a thickness of 20 μm or more is formed is 200 ° C. for 60 minutes, 220 ° C. for 20 minutes, 240 ° C. for 8 minutes, and 260 ° C. It was 3 minutes. Even when the material of the base material 11 is cobalt, the sodium film 12 is formed at substantially the same temperature and time as nickel.

  After immersing the base material 11 in the molten metal sodium 51 at a temperature equal to or higher than the wetting temperature corresponding to the material of the base material 11 for a time longer than the immersion time, the base material 11 is pulled up from the molten metal sodium 51 to thereby remove the base material 11 from sodium. The negative electrode 1 formed by coating with the film 12 is manufactured. The base material 11 made of tungsten, chromium or molybdenum can form the sodium film 12 at a lower temperature than the substrate 11 made of nickel, and the sodium film 12 can be formed in a shorter time at the same temperature. can do. Therefore, it is desirable that the material of the base material 11 be tungsten, chromium, or molybdenum from the viewpoint of energy saving and efficiency improvement in the process of manufacturing the negative electrode 1.

  After the negative electrode 1 is manufactured, the positive electrode material 22 of the positive electrode 2 and the sodium film 12 of the negative electrode 1 face each other, and the separator 3 is interposed between the positive electrode 2 and the negative electrode 1, so that the positive electrode 2, the separator 3, and the negative electrode 1 is placed in the battery container 41. The inside of the battery container 41 has an insulating structure by a method such as coating with an insulating resin in order to prevent a short circuit between the positive electrode 2 and the negative electrode 1. The lid 42 is attached to the battery container 41 while being insulated from the battery container 41 by a method such as bonding to the battery container 41 using an insulating adhesive. Further, the positive electrode current collector 21 of the positive electrode 2 is electrically connected to the battery container 41 directly or via a conductive member such as a lead wire, and the base material 11 of the negative electrode 1 is similarly connected to the lid portion 42. Electrically connected. As described above, the molten salt battery according to the present embodiment is manufactured.

  The molten salt battery functions as a secondary battery having the battery container 41 as a positive electrode terminal and the lid portion 42 as a negative electrode terminal within a temperature range below the melting point of sodium and at which the molten salt melts. In the present embodiment, the molten salt melts at a temperature of 80 ° C. or higher to become an electrolytic solution. That is, in the molten salt battery according to the present embodiment, the molten salt becomes an electrolytic solution containing sodium ions at a temperature of 80 ° C. to 98 ° C., and operates as a secondary battery. The configuration of the molten salt battery shown in FIG. 1 is a schematic configuration. In the molten salt battery, a heater that heats the inside, an elastic member that absorbs deformation of the positive electrode 2 or the negative electrode 1 due to charge / discharge, Alternatively, other components (not shown) such as a temperature sensor may be included.

  As described above in detail, in the molten salt battery according to the present embodiment, the negative electrode 1 is manufactured by covering the metal base 11 with the sodium film 12. Since the metal base 11 has higher strength than metal sodium, the negative electrode 1 in the present invention has higher strength and can be made larger than an electrode formed from metal sodium. Moreover, since the negative electrode 1 in this invention is manufactured by immersing the base material 11 in the molten metal sodium 51, without requiring metal sodium machining, the facilities required for manufacture become simpler, and the negative electrode 1 It becomes easier to increase the size. Therefore, a practical molten salt battery in which the negative electrode 1 using sodium as the negative electrode active material is enlarged can be realized.

  In addition, in this Embodiment, although the form which coat | covers the single side | surface of the rectangular-shaped base material 11 with the sodium film | membrane 12 was shown, the molten salt battery of this invention coat | covers both surfaces of the base material 11 with the sodium film | membrane 12. The form provided with the negative electrode 1 formed may be sufficient. In the case of this form, the sodium film 12 is formed on both surfaces of the base material 11 by immersing the base material 11 in molten metal sodium 51 having no temperature gradient. The molten salt battery of this embodiment includes two positive electrodes 2 and a separator 3, and is configured by disposing the separator 3 and the positive electrode 2 at positions facing both surfaces of the negative electrode 1. By forming the sodium film 12 on both surfaces of the base material 11 and providing the two positive electrodes 2, the capacity of the molten salt battery can be increased. Further, the shape of the molten salt battery is not limited to a rectangular parallelepiped shape, and may be other shapes. For example, a molten salt battery is provided by forming the base material 11 in a columnar shape, including the negative electrode 1 having the surface of the base material 11 covered with a sodium film 12, and including the cylindrical separator 3 and the positive electrode 2 around the negative electrode 1. The shape may be cylindrical.

  In the present embodiment, an example of a molten salt battery that operates at a temperature of 80 ° C. or higher using a molten salt composed of an FSI or TFSI anion and a cation of sodium and / or potassium as an electrolyte is shown. As long as the molten salt battery of the present invention is a molten salt that melts at a temperature not higher than the melting point of sodium, a form using other molten salt as an electrolyte may be used. A molten salt battery using another molten salt as an electrolyte operates at a temperature equal to or higher than a temperature at which the molten salt melts.

(Embodiment 2)
Embodiment 2 shows a mode in which a material having low reactivity with sodium is used as a material for a negative electrode substrate. The configuration of the molten salt battery according to Embodiment 2 is the same as that of Embodiment 1, and the description thereof is omitted.

  FIG. 5 is a schematic cross-sectional view of negative electrode 1 of the molten salt battery according to Embodiment 2. The negative electrode 1 has a three-layer structure. On the base material 11 formed in the shape of a rectangular plate with a metal having no wettability of the molten metal sodium 51, a base film 13 which is a base of the sodium film 12 and having a wettability of the molten metal sodium 51 is formed. In addition, a sodium film 12 is formed on the base film 13. For example, the main material of the base material 11 is aluminum, and the base material 11 is formed of a metal whose main component is metal aluminum or an aluminum alloy. The thickness of the base film 13 is 50 nm or more, and the thickness of the sodium film 12 is 20 μm to 100 μm, as in the first embodiment. The material of the base film 13 is nickel, cobalt, iron, tungsten, chromium or molybdenum having wettability with the molten metal sodium 51.

  The base film 13 is formed by performing metal plating on the surface of the substrate 11. For example, the base film 13 is formed by performing strike plating on the surface of the substrate 11. Further, for example, the base film 13 is formed by plating the surface of the base material 11 with zinc and then plating the material metal of the base film 13 as a zincate treatment. Further, the base film 13 may be formed by physical vapor deposition or vapor phase plating. The base film 13 does not need to be formed of a single metal, and may be formed of an alloy of nickel, cobalt, iron, tungsten, chromium, or molybdenum, and may contain a compound with another substance. .

  The sodium film 12 is formed by immersing the base material 11 having the base film 13 formed on the surface in the molten metal sodium 51. A compound is formed at the interface between the base film 13 and the molten metal sodium 51 at a temperature equal to or higher than the wetting temperature corresponding to the material of the base film 13, and the wettability between the base film 13 and the molten metal sodium 51 is improved. Molten metal sodium 51 adheres to the base film 13 to form the sodium film 12. When the material of the base film 13 is tungsten, chromium or molybdenum, the sodium film 12 is formed at a temperature of 160 ° C. or higher. When the material of the base film 13 is iron, the sodium film 12 is formed at a temperature of 140 ° C. or higher. When the material of the base film 13 is nickel or cobalt, the sodium film 12 is formed at a temperature of 195 ° C. or higher. Since nickel is most resistant to molten salt, it is desirable that the material of the base film 13 is nickel from the viewpoint of the life of the molten salt battery. Further, from the viewpoint of energy saving and efficiency improvement in the process of manufacturing the negative electrode 1, it is desirable that the material of the base film 13 be iron, tungsten, chromium, or molybdenum.

  After immersing the base material 11 in a molten metal sodium 51 having a temperature equal to or higher than the wetting temperature corresponding to the material of the base film 13 for a time longer than the time for forming the sodium film 12 having a thickness of 20 μm or more, the base material 11 is melted. The negative electrode 1 is manufactured by pulling up from the sodium 51. After the negative electrode 1 is manufactured, a molten salt battery is manufactured using the manufactured negative electrode 1 as in the first embodiment. Also in this embodiment, it is easier to increase the size of the negative electrode 1 than to form the electrode with metallic sodium, and a practical molten salt in which the negative electrode 1 using sodium as the negative electrode active material is increased in size. A battery becomes feasible.

  Since aluminum is lightweight, if the material of the base material 11 can be aluminum, the weight of the negative electrode 1 can be reduced. However, since aluminum does not have the wettability of the molten metal sodium 51, it is difficult to form the sodium film 12 directly on the aluminum base material 11. In the present embodiment, the base film 13 is formed of a metal having wettability of the molten metal sodium 51 on the substrate 11, and the sodium film 12 is formed on the base film 13, whereby the wettability of the molten metal sodium 51 is formed. The production of the negative electrode 1 using the base material 11 that does not have any of them was made possible. For this reason, it is possible to reduce the weight of the molten salt battery by using aluminum as the main material of the base material 11 of the negative electrode 1 using sodium as the negative electrode active material.

(Embodiment 3)
The configuration of the molten salt battery according to the third embodiment is the same as that of the second embodiment, and the materials of the base material 11 and the base film 13 of the negative electrode 1 are different from those of the second embodiment. In the present embodiment, the main material of the base material 11 is nickel. The base material 11 is formed of a metal whose main component is metallic nickel or a nickel alloy. The material of the base film 13 is a metal that has better wettability with molten metal sodium than nickel, such as iron, tungsten, chromium, or molybdenum. The base film 13 does not need to be formed of a single metal but may be formed of an alloy of iron, tungsten, chromium, or molybdenum, and may include a compound with another substance. The manufacturing method of negative electrode 1 and the manufacturing method of the molten salt battery are the same as in the second embodiment. Also in this embodiment, it is easier to increase the size of the negative electrode 1 than to form the electrode with metallic sodium, and a practical molten salt in which the negative electrode 1 using sodium as the negative electrode active material is increased in size. A battery becomes feasible.

  In the present embodiment, by using nickel as the main material of the substrate 11, the resistance of the negative electrode 1 to the molten salt that is the electrolyte of the molten salt battery is increased, and the life of the molten salt battery is extended. Moreover, the sodium film 12 is directly formed on the base material 11 by forming the sodium film 12 on the base film 13 formed of a metal having better wettability of molten metal sodium than nickel such as iron, tungsten, chromium or molybdenum. Therefore, the sodium film 12 can be formed at a lower temperature or in a shorter time. Therefore, in the present embodiment, it is possible to achieve both a long life of the molten salt battery and energy saving and efficiency improvement in the process of manufacturing the negative electrode 1.

  In the above first to third embodiments, an embodiment in which an electrode formed by coating a metal substrate with a sodium film is used as a negative electrode is shown. However, the molten salt battery of the present invention is not limited to this. Alternatively, an electrode in which the base material is coated with a sodium film may be used as the positive electrode. For example, depending on the material of the other electrode, an electrode in which the base material is coated with a sodium film can be used as the positive electrode. Moreover, it is also possible to use the electrode which coat | covered the base material with the sodium film as a positive electrode after discharge.

DESCRIPTION OF SYMBOLS 1 Negative electrode 11 Base material 12 Sodium film | membrane 13 Base film 2 Positive electrode 3 Separator 41 Battery container 42 Cover part 51 Molten metal sodium

Claims (9)

In the molten salt battery using sodium as the active material of the electrode,
The electrode is formed by coating a metal base with a sodium film, and a molten salt battery. On the base material, a metal having better wettability of molten metal sodium than the base material is formed, and a base film as a base of the sodium film is formed, and the sodium film is formed on the base film The molten salt battery according to claim 1, wherein:   The molten salt battery according to claim 2, wherein the material of the base film is iron, tungsten, chromium, or molybdenum.   The molten salt battery according to claim 2, wherein the material of the base film is nickel or cobalt.   The molten salt battery according to claim 1, wherein a main material of the base material is nickel.   The molten salt battery according to claim 2, wherein a main material of the base material is aluminum. In a method of manufacturing a molten salt battery using sodium as an active material of an electrode,
By immersing a metal base in molten metal sodium, the base is covered with a sodium film,
A method for producing a molten salt battery, comprising producing the molten salt battery using the base material coated with a sodium film as one electrode. Before immersing the base material in molten metal sodium, a base film that forms the base of the sodium film is formed on the base material with a metal having better wettability of the molten metal sodium than the base material,
The method for manufacturing a molten salt battery according to claim 7, wherein the temperature of the molten sodium metal is adjusted to be equal to or higher than a temperature at which the components of the base film react with sodium. The base material is formed in a flat plate shape,
Generate a temperature gradient in the molten metal sodium,
The method for producing a molten salt battery according to claim 7 or 8, wherein the base material is immersed in molten metal sodium in a direction in which the temperature changes in the thickness direction.

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