JP2012109194A - Molten salt battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molten salt battery pack which allows for rigid mechanical connection and electrical connection of adjoining molten salt batteries simultaneously.SOLUTION: Connection tabs 42 and 22 of the positive electrode and negative electrode 21 in one and the other adjoining molten salt batteries are connected, respectively, to two connection members 43 and 23 consisting of an aluminum alloy and having a U-shaped plan view. When the sidewalls 1A, 1B of the adjoining battery containers 10, 10 are abutted and fastened using a bolt 51 and nuts 52, 52 consisting of an aluminum alloy, the two connection members 43 and 23 are connected electrically by the bolt 51 and nuts 52, 52.

Description

  The present invention relates to a molten salt assembled battery in which a plurality of molten salt batteries each including a battery container containing a positive electrode and a negative electrode are arranged and electrically connected.

  In recent years, power generation using natural energy such as sunlight and wind power has been promoted as a means for generating electric power without discharging carbon dioxide. In the case of power generation using natural energy, the amount of power generation is often affected by natural conditions such as climate and weather, and it is difficult to adjust the amount of power generation according to power demand. It becomes. In order to charge and discharge the generated electrical energy and level it, a high-energy density, high-efficiency, large-capacity storage battery is required. As a storage battery that satisfies these conditions, molten salt is used as the electrolyte. Salt batteries are attracting attention.

  A unit cell of a molten salt battery includes, for example, sodium, between a positive electrode in which an active material made of a sodium compound is contained in a current collector, and a negative electrode in which a metal such as tin is plated on the current collector. A power generation element including a separator impregnated with a molten salt composed of an alkali metal cation such as potassium and an anion containing fluorine is provided in the battery container.

  By the way, it is not limited to a molten salt battery, but is often used as an assembled battery by combining a plurality of single cells. For example, Patent Document 1 discloses an assembled battery in which five unit cells are connected in parallel to a square nonaqueous electrolyte secondary battery with copper connection leads.

JP 2009-211136 A

  However, in the assembled battery disclosed in Patent Document 1, a positive electrode terminal and a negative electrode terminal project from the lid of the outer container (battery container), and the connection leads are connected to the positive electrode terminal and the negative electrode terminal of the adjacent unit cell. In order to electrically connect the two, the mechanical connection that firmly fixes the cells using bolts and nuts and the electrical connection must be performed separately. there were.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a molten salt assembled battery that can simultaneously perform mechanically strong electrical connection between adjacent molten salt batteries. There is to do.

  (1) In the molten salt assembled battery according to the present invention, one or a plurality of positive electrodes and negative electrodes are accommodated in a battery container made of a conductor, and current is taken out from connection tabs of each of the positive electrodes and the negative electrodes. In a molten salt assembled battery in which a plurality of molten salt batteries are connected in series, the battery containers of adjacent molten salt batteries are fastened using bolts and nuts made of conductors, and the adjacent The molten salt battery includes two connection members that electrically connect the bolts to connection tabs of a positive electrode and a negative electrode, respectively, and the bolts and nuts are insulated from the battery containers of the adjacent molten salt batteries. It is characterized by.

In the invention of (1), the connection tabs of the positive electrode and the negative electrode included in one and the other of the adjacent molten salt batteries are connected to the two connection members, respectively, and the battery of the adjacent molten salt battery When the containers are fastened using a bolt and a nut made of a conductor, the two connecting members are electrically connected to each other via the bolt and the nut. For this reason, the molten salt batteries that are mechanically firmly connected are electrically connected in series.
Further, since the bolts and nuts are insulated from each battery container, electrical insulation between the positive and negative electrodes electrically connected between adjacent molten salt batteries and each battery container mechanically connected Is preserved.

  (2) Further, in the molten salt assembled battery according to the present invention, the battery container has a container body having an opening in the upper part, and a lid for sealing the opening of the container body, and the positive electrode and the negative electrode are laterally arranged. The positive electrode and the negative electrode are immersed in a molten salt.

In the invention of (2) above, the upper part of the container body of the battery container is open, and the positive electrode and the negative electrode arranged side by side in the opposite direction are immersed in a molten salt filled in the battery container. Let
Thereby, the positive electrode and the negative electrode superimposed on the outside of the battery container can be easily inserted into the container main body from above the opening of the container main body with the opposing direction as the horizontal direction. Moreover, molten salt can be inject | poured from the opening of a container main body, and it can spread suitably between a positive electrode, a separator, and a negative electrode. Furthermore, the influence of corrosion etc. by molten salt is reduced by positioning the above-mentioned connecting member above the liquid surface of the molten salt.

  (3) Moreover, the molten salt assembled battery which concerns on this invention is characterized by the parallel arrangement direction of the said positive electrode and a negative electrode being a direction which cross | intersects the arrangement direction of the said molten salt battery.

In the invention of (3), the direction in which the positive electrode and the negative electrode are arranged side by side and the direction in which the molten salt batteries are arranged next to each other are crossed. That is, the molten salt batteries are arranged in a direction along the surfaces where the positive electrode and the negative electrode face each other.
As a result, when the battery container has a rectangular parallelepiped shape, the molten salt batteries are arranged side by side with the side walls that are normally positioned on the short side in a plan view.
In addition, when the connection tabs for taking out current from each of the positive electrode and the negative electrode are arranged side by side on both sides in the direction along the surface where the positive electrode and the negative electrode face each other, the connection tabs of the positive electrode and the negative electrode for each molten salt battery By aligning the juxtaposed direction in the same direction, the length of the connection member connecting the connection tabs and the bolts is shortened.

  (4) Moreover, as for the molten salt assembled battery which concerns on this invention, the battery container of the said adjacent molten salt battery has a through-hole connected in the upper position from the liquid level of the said molten salt, In this through-hole, The bolt is inserted, and an insulating bushing for insulatingly supporting the bolt and nut in the through hole is provided.

In the invention of the above (4), an insertion hole is formed in the abutting portion between the battery containers so that the spaces in the battery containers of adjacent molten salt batteries communicate with each other at a position above the liquid level of the molten salt. Insulating bushings are further fitted into the insertion holes, and the bolts are inserted into the bushings.
Thereby, the battery containers of adjacent molten salt batteries are fastened with the bolts and nuts that are not visually recognized from the outside, and insulation between each battery container and the bolts and nuts is easily ensured.

  (5) Moreover, the molten salt assembled battery which concerns on this invention is characterized by the said connection tab, a connection member, a volt | bolt, and a nut containing the same kind of electrically conductive material as the said positive electrode and a negative electrode.

In the invention of (5) above, the connection tab and the connection member, the bolt and the nut, the positive electrode and the negative electrode contain the same kind of conductive material. That is, all the members for connecting between the positive electrode and negative electrode of adjacent molten salt batteries contain the same kind of conductive material as the positive electrode and negative electrode.
Thereby, the electric corrosion which may occur when the member which connects between a positive electrode and a negative electrode contacts molten salt is suppressed.

  (6) In the molten salt assembled battery according to the present invention, the conductive material is an alloy containing 90% by weight or more of aluminum.

  In the invention of (6) above, since all the members for connecting between the positive electrode and the negative electrode of adjacent molten salt batteries, and the positive electrode and the negative electrode contain an alloy containing 90% by weight or more of aluminum, As will be described later, it is excellent in workability, corrosion resistance and deterioration resistance. When the content is less than 90% by weight, the workability is particularly deteriorated.

  (7) Moreover, the molten salt assembled battery which concerns on this invention is equipped with the conducting wire connected to the said volt | bolt, and this conducting wire is a through-hole formed in the cover body which one battery container of the said adjacent molten salt battery has. And is insulated from the through hole.

In the invention of (7) above, a through hole is formed in the lid of one of the two battery containers of the molten salt battery adjacent to each other, and the adjacent to the through hole. The lead wire connected to the bolt for fastening the molten salt battery is insulated from the lid and inserted.
As a result, when monitoring the battery voltage and the charging depth of each of the molten salt batteries arranged in line is performed using a conductor, each molten salt is discharged by performing an amount of discharge corresponding to the magnitude of the charging depth. The degree of progress of battery deterioration can be made uniform.

  (8) Further, in the molten salt assembled battery according to the present invention, one or a plurality of positive electrodes and negative electrodes are accommodated in a battery container made of a conductor, and an electric current is taken out from a connection tab of each of the positive electrode and the negative electrode. In the molten salt assembled battery in which a plurality of molten salt batteries are connected in parallel, the battery containers of adjacent molten salt batteries are fastened using at least two bolts and nuts made of conductors. And two connecting members for electrically connecting one bolt to each positive electrode provided in each of the adjacent molten salt batteries, and another bolt on a connection tab of a negative electrode provided in each of the adjacent molten salt batteries. And the other two connecting members that electrically connect each other, wherein the bolt and the nut are insulated from each battery container of the adjacent molten salt battery.

In the invention of (8), one or a plurality of positive electrode connection tabs provided in each of the adjacent molten salt batteries and one bolt made of a conductor are separately provided by two connection members made of a conductor. The battery containers of adjacent molten salt batteries are fastened using the one bolt and one nut made of a conductor. Similarly, one or a plurality of negative electrode connection tabs provided in each of the adjacent molten salt batteries and another bolt made of a conductor are connected separately by two other connection members made of a conductor, and the other The battery containers of adjacent molten salt batteries are fastened together using a bolt and another nut made of a conductor. For this reason, the molten salt batteries electrically connected in parallel are mechanically firmly connected.
In addition, since the one bolt and nut and the other bolt and nut are insulated from each battery container, the positive and negative electrodes electrically connected in parallel between adjacent molten salt batteries, a machine Electrical insulation from each battery container connected to each other is maintained.

  (9) Further, the present invention provides a molten salt assembled battery in which a plurality of battery containers for molten salt batteries containing electrodes are connected and the electrodes of each battery container are electrically connected in series or in parallel with each other. Each of the adjacent molten salt batteries includes a fastening member that is inserted into a hole formed in the conductive side wall of each battery container of the adjacent molten salt battery and fastens the battery containers, and the adjacent molten salt battery. Separately provided electrodes are electrically connected to one end and the other end of the fastening member, respectively, and the fastening member is insulated from each battery container of the adjacent molten salt battery, and the fastening member is fastened to And an insulating seal member that seals the hole.

  In the invention of (9), two adjacent electrodes are electrically connected to each other via the connecting member by fastening the battery containers of the molten salt batteries adjacent to each other using a fastening member made of a conductor. Connected to. In this way, the molten salt batteries that are mechanically firmly connected are electrically connected in series or in parallel. Further, by fastening, the insulating sealing member seals the hole of each battery container to ensure sealing performance, and insulates the fastening member from the battery container.

  (10) In the molten salt assembled battery of (9), the fastening member is a bolt and a nut, and the insulating seal member is provided for each battery container, and the bolt A ring-shaped rubber member for interpolating a portion other than the head of the rubber member, and covering the rubber member so as to be wrapped from one end side in the axial direction, and a part of the rubber member protruding from the other axial end side A pressing member, and an insulating washer interposed between the pressing member and the connecting member, and the pressing member presses the rubber member and bites into the hole by fastening of the fastening member. Accordingly, the molten salt assembled battery may be configured to seal the hole.

  In this case, by allowing the rubber member to bite into the hole, the gap between the hole and the bolt passed through the hole is completely closed, and excellent sealing performance against liquid and gas can be obtained. In addition, since the seals are independent for each hole, the sealing performance is not easily impaired even when vibration or impact is applied to the battery container. On the other hand, the connecting member is insulated from the battery container by the insulating washer.

  According to the present invention, a mechanically strong connection and an electrical connection between adjacent molten salt batteries can be simultaneously performed while maintaining an electrical insulation relationship between the electrodes (positive electrode and negative electrode) and the battery container. Can be done.

It is a perspective view which shows typically the principal part structure of the molten salt battery which comprises the molten salt assembled battery which concerns on Embodiment 1 of this invention. It is a cross-sectional view which shows typically the structure of the laminated | stacked electric power generation element. A is a top view schematically showing the configuration of the molten salt battery, and B is a longitudinal sectional view schematically showing the configuration of the molten salt battery. A is a top view of the cover body of a molten salt battery, B is a longitudinal cross-sectional view of the cover body. It is a longitudinal cross-sectional view of the molten salt assembled battery which concerns on Embodiment 1 of this invention. It is an expanded sectional view of the connection part of the molten salt assembled battery shown in FIG. FIG. 6 is a partial top view schematically showing a configuration of a molten salt assembled battery according to a modification of Embodiment 1 of the present invention. It is a partial top view which shows schematically the structure of the molten salt assembled battery which concerns on Embodiment 2 of this invention. It is a partial top view which shows the structure of the molten salt assembled battery which concerns on the modification of Embodiment 2 of this invention schematically. It is a partial top view which shows the structure of the molten salt assembled battery which concerns on Embodiment 3 of this invention schematically. It is an expanded sectional view of the connection part of the molten salt assembled battery in Embodiment 4 of this invention. (A) is sectional drawing which shows the rubber member and pressing member in the free state before mounting | wearing like FIG. 11, (b) is an expanded rubber member and pressing member in the state of FIG. It is sectional drawing shown.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
Embodiment 1
1 is a perspective view schematically showing a main part configuration of a molten salt battery constituting a molten salt assembled battery according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view schematically showing a configuration of stacked power generation elements. 3A is a top view schematically showing the structure of the molten salt battery, B is a longitudinal sectional view schematically showing the structure of the molten salt battery, and FIG. 4A is a plan view of the lid of the molten salt battery. Drawing B is a longitudinal section of the lid.

  In the molten salt battery of the present invention, a plurality (six in the figure) of negative electrodes 21, 21,... 21 in a rectangular plate and a plurality (in the figure) accommodated in bag-shaped separators 31, 31,. , And 41) rectangular plate-like positive electrodes 41, 41,... 41 are arranged in parallel in the horizontal direction (front-rear direction in the figure) alternately facing each other in the vertical direction. One set of negative electrode 21, separator 31 and positive electrode 41 constitute one power generation element, and in this embodiment, five power generation elements and one negative electrode 21 are laminated to form a rectangular parallelepiped aluminum (hereinafter simply referred to as aluminum). It is accommodated in a battery container 10 made of an alloy. The inner side of the battery container 10 is subjected to insulation treatment by fluororesin coating.

The battery container 10 includes a container body 1 having an opening 1E on the upper surface, and a rectangular flat plate-shaped lid that is fitted in a step 1G formed on the inner periphery of the opening 1E of the container body 1 to close the opening 1E. 7. The container body 1 includes two side walls 1A and 1B located on the short side in plan view, two side walls 1C and 1D located on the long side, and a bottom wall 1F. On the inner side of the upper end portions of the four side walls 1A, 1B, 1C, 1D of the container body 1, a step portion 1G having a vertical dimension equal to the plate thickness of the lid body 7 is formed over the entire circumference. The lid body 7 is a rectangular parallelepiped plate body, and the outer dimension in plan view is substantially the same as or slightly smaller than the inner circumferential dimension of the step portion 1G of the container body 1. Cover body 1 from above with lid 7
The lid 7 is fitted into the opening 1E of the container body 1 by being dropped into the step 1G.

The upper ends of the negative electrodes 21, 21,... 21 have connection tabs 22, 22,・
-The lower end part of 22 is joined. The upper portions of the connection tabs 22, 22, 22 and 22, 22, 22 are two opposite surfaces of the two arm portions 231 and 231 included in the connection member 23 having a U-shape opened in the plan view on the side wall 1B side. Are welded to each. The connection member 23 has a rectangular connection plate portion 232 whose surface direction is parallel to the arm portions 231 and 231, and is attached to the upper center of the connection plate portion 232 so as to face the through hole 1 </ b> H formed in the side wall 1 </ b> A. A hole 233 is provided.

The upper ends of the positive electrodes 41, 41,... 41 are connected to the connection tabs 42, 42, 42 made of rectangular aluminum alloy for taking out current on the side close to the other side wall 1 B located on the short side of the container body 1.・
-The lower end part of 42 is joined. The upper portions of the connection tabs 42, 42 and 42, 42, 42 are respectively opposite to the two opposite surfaces of the two arm portions 431 and 431 of the connection member 43 having a U-shape in plan view that is open to the side wall 1A. Welded. The connection member 43 has a rectangular connection plate portion 432 whose surface direction is parallel to the arm portions 431 and 431, and is mounted in the upper center of the connection plate portion 432 so as to face the through hole 1H formed in the side wall 1B. A hole 433 is provided. The five power generating elements and one negative electrode 21 described above are electrically connected in parallel to constitute a molten salt battery having a large battery capacity.

  The negative electrodes 21, 21,... 21 are made of aluminum foil plated with tin, which is a negative electrode active material. Aluminum is a material suitable for the current collector of each positive / negative electrode, and has corrosion resistance against molten salt. The negative electrodes 21, 21,... 21 have an active material-containing thickness of about 0.14 mm, and the vertical and horizontal dimensions are 100 mm and 120 mm, respectively.

The positive electrodes 41, 41,... 41 have an aluminum alloy porous body as a current collector, and the current collector is filled with a mixture containing a binder, a conductive additive, and NaCrO _{2 as a} positive electrode active material, The plate thickness is about 1 mm. The vertical and horizontal dimensions of the positive electrodes 41, 41,... 41 are smaller than the vertical and horizontal dimensions of the negative electrodes 21, 21,. The outer edges of the positive electrodes 41, 41,... 41 face the peripheral portions of the negative electrodes 21, 21,. The current collector of the positive electrodes 41, 41,... 41 may be, for example, a nonwoven fabric made of fibrous aluminum.

  The separators 31, 31,... 31 are made of a fluororesin film that is resistant to molten salt at a temperature at which the molten salt battery operates, and are formed in a porous and bag-like manner. The separators 31, 31,... 31 and the negative electrodes 21, 21,... 21 and the positive electrodes 41, 41,... Soaked down from the position. Thereby, a slight drop in the liquid level is allowed.

  Each of the connecting members 23 and 43 serves as an external electrode for connecting the negative electrodes 21, 21,... 21 and the positive electrodes 41, 41,. It is located above the liquid level. The molten salt 6 is composed of an FSI (bisfluorosulfonylimide) or TFSI (bistrifluoromethylsulfonylimide) anion and a cation of sodium and / or potassium, but is not limited thereto.

In the configuration described above, the entire battery container 10 is heated to 85 ° C. to 95 ° C. using an external heating means (not shown), whereby the molten salt 6 is melted and charged and discharged via the connecting members 23 and 43. Is possible.
Next, a molten salt assembled battery in which a plurality of molten salt batteries are electrically connected in series to increase the battery voltage will be described. FIG. 5 is a longitudinal sectional view of the molten salt assembled battery according to Embodiment 1 of the present invention, and FIG. 6 is an enlarged sectional view of a connecting portion of the molten salt assembled battery shown in FIG. In addition, although the example which connected four molten salt batteries is shown in FIG. 5, the number of connection is not limited to four. In the case where the number of connections is four, the nominal voltage of the molten salt assembled battery is 12V, and it is easy to divert equipment (for example, a charger) used for existing automotive lead acid batteries.

  In the molten salt assembled battery, four molten salt batteries in a state where the lid body 7 is not mounted are arranged so that the side walls 1A, 1B on the short side of the adjacent container bodies 1, 1 face each other. In this state, the five power generation elements (the negative electrode 21 and the positive electrode 41 wrapped in the separator 31) and one negative electrode 21 and the molten salt 6 connected in parallel by the connecting members 23 and 43 are put into each container body 1. Is done.

  Through holes 1H and 1H penetrating in the lateral direction are provided in the upper center of the abutted side walls 1A and 1B. Teflon (registered) is provided from the side of the side walls 1A and 1B with respect to the through holes 1H and 1H. Insulating bushings (bearing cylinders) 81, 81 made of a trademark) are fitted. Of the butted portions of the side walls 1A and 1B, a concave groove is provided in a portion facing the through holes 1H and 1H, and Viton (registered trademark) is provided between the concave groove and a gap where the bushings 81 and 81 are opposed to each other. An O-ring 82 is attached.

  The bushing 81, 81 has an outer diameter substantially the same as the inner diameter of the bushing 81, 81, and a bolt 51 made of an aluminum alloy is passed through a washer 53 made of an aluminum alloy and a mounting hole 233 of the connection plate portion 232. Are inserted from the side wall 1A side. The bolt 51 is screwed into the nuts 52 and 52 made of an aluminum alloy via the attachment hole 433 of the connection plate portion 432 on the side wall 1B side. The two nuts 52, 52 are used to prevent loosening of the screwing.

A lead wire 54 made of an aluminum alloy is joined to the washer 53, and the lead wire 54 is inserted into an insulating member fitted in a through-hole 7 </ b> B provided in the lid body 7, and the battery container 10. Has been pulled out of. The lead wire 54 serves as a terminal for monitoring the voltage at the connection point of two molten salt batteries connected in series from the outside and discharging each molten salt battery individually as appropriate.
In addition, when the bolt 51 is inserted into the bushings 81, 81, the washer 53 is not limited to the side wall 1 </ b> A side, but the bolt 51 is connected to the nut 52, via the washer 53 on the side wall 1 </ b> B side. 52 may be screwed. In this case, a through hole 7B may be formed in the lid body 7 fitted to the side wall 1B in FIG. 6, and the lead wire 54 may be inserted into the insulating member fitted in the through hole.

  In the molten salt battery positioned at both ends of the molten salt assembled battery, for example, the bushings 83 and 83 whose lengths of the portions fitted into the through-holes 1H are about half of the bushing 81 are formed on the side wall 1B (or the side wall 1A). From both sides, an O-ring is appropriately inserted and inserted into the through hole 1H. Then, the bolts 51 are inserted into the bushings 83, 83 from the outside of the side wall 1B (or side wall 1A) through the other connecting member 24 (or 44), and connected from the inside of the side wall 1B (or side wall 1A). The nuts 52 and 52 are screwed through the member 43 (or 23).

  With the above configuration, the side walls 1A, 1B of the two adjacent molten salt batteries are fastened by the bolts 51 and the nuts 52, 52 via the insulating bushings 81, 81, and the connection members 23, 43 are Electrical connection is established via bolts 51 and nuts 52, 52 (hereinafter simply referred to as bolts 51). The bolt 51 and the nuts 52 and 52 are electrically insulated from the side walls 1A and 1B.

On the other hand, connection tabs 22, 22,... 22 and 42, 42,... 42 are welded to each of the connection members 23 and 43, and the connection tabs 22, 22,. .. 42 are respectively joined to the negative electrodes 21, 21,... 21 and the positive electrodes 41, 41,. Therefore, the negative electrodes 21, 21,... 21 and the positive electrodes 41, 41,... 41 and the positive electrodes 41, 41,. Matching molten salt batteries are electrically connected in series.
After each connection described above, the lid body 7 is fitted into the opening 1E of each container body 1 and, for example, laser light is irradiated from above to weld the peripheral edge portion 7A of the lid body 7 to the container body 1.

Now, the conductive material used for the molten salt battery will be described below.
When a metal (conductive material) having a different ionization tendency is placed at a site in contact with the electrolyte, such as the molten salt 6, electric corrosion occurs due to current flowing from one metal to the other. Therefore, in the first embodiment, as described above, the connection tabs 22, 22,... 22, 42, 42,
..42, connecting members 23 and 43, bolts 51 and nuts 52 and 52 are negative electrodes 21, 21
.. And 21 and positive electrodes 41, 41,... 41, and the same kind of conductive material (aluminum alloy in the first embodiment) is included to prevent the occurrence of electrolytic corrosion. As described above, the battery container 10 is also made of an aluminum alloy.

Next, the ratio of elements to be included in the aluminum alloy will be described.
For example, JIS standard aluminum alloy A5052P has copper (Cu), chromium (Cr), iron (Fe), magnesium (Mg), manganese (Mn), titanium (Ti), silicon (Si) as alloy components. , And zinc (Zn). The solid solubility limit of these components (the limit for forming a solid solution, that is, the limit for melting as an alloy) is small, and if the proportion of each component exceeds 10% (weight%, the same applies hereinafter), the workability Therefore, the alloy component added to aluminum is limited to 10%.

  By the way, since the molten salt battery operates in an environment of 85 ° C. to 95 ° C. as described above, the bolt 51 and the nuts 52 and 52 that are mechanically constrained are subjected to thermal stress in the process of heating and cooling. It is assumed that it will occur. For this reason, especially with respect to the bolt 51 and the nuts 52 and 52, it is necessary to consider creep resistance.

Specifically, creep resistance is improved by setting the ratio of zirconium (Zr) and titanium added to aluminum to 0.1 to 0.3%. When this proportion is smaller than 0.1%, the effect of improving the creep resistance cannot be obtained. Moreover, since zirconium and titanium form an intermetallic compound with hardly dissolving in aluminum, the upper limit of the above ratio is set to 0.3%.
When it exceeds 0.3%, the workability deteriorates, and the compound phase precipitated in the aluminum matrix phase causes a corrosion reaction on the positive electrode 41, 41,.

Below, the limit value of each alloy component is demonstrated.
The ratio of copper (Cu), chromium (Cr), and iron (Fe) is 0.5% or less, 0.5% or less, and 1% or less, respectively. At room temperature, copper, chromium and iron hardly dissolve in aluminum. When the proportion of copper is larger than 0.5%, various intermetallic compound phases are often formed. When the proportion of chromium is larger than 0.5%, Al ₇ Cr is often formed. Further, when the proportion of iron is larger than 1%, FeAl ₃ is often formed.
The copper compound phase, Al ₇ Cr and FeAl ₃ deposited in the aluminum matrix phase have low corrosion resistance and cause a corrosion reaction on the positive electrode 41, 41,.

The proportion of magnesium (Mg) is 4% or less. At normal temperature, magnesium often exists in a supersaturated state, but when the proportion of magnesium is particularly greater than 4%, Al ₂ Mg ₃ may be precipitated. Since Al ₂ Mg ₃ precipitated in the aluminum matrix significantly reduces workability, it becomes difficult to process the battery container 10.

The proportions of manganese (Mn) and titanium (Ti) are 1.5% or less and 0.2% or less, respectively. At room temperature, manganese and titanium are hardly dissolved in aluminum and often form Al ₆ Mn and TiAl ₃ , respectively.
Since Al ₆ Mn and TiAl ₃ precipitated in the aluminum matrix significantly reduce workability, it is difficult to process the battery container 10.

  The ratio of silicon (Si) is 1.5% or less. At room temperature, silicon is often present in a supersaturated state with almost no solid solution in aluminum. However, when the proportion of silicon is particularly greater than 1.5%, it may precipitate as a single phase of silicon. In this case, there is a problem that SiNa alloy is formed in the reaction on the negative electrode 21, 21,.

  The ratio of zinc (Zn) is 1% or less. The solid solubility limit of zinc at room temperature is about 1%. When the proportion of zinc is greater than 1%, there is a high possibility that a single phase of zinc precipitates and local corrosion occurs.

As described above, according to the first embodiment, the connection tabs of the five positive electrodes and the six negative electrodes included in one and the other of the adjacent molten salt batteries are made of an aluminum alloy having a U-shape in plan view. When connecting the two connection members to each other, and fastening the side walls of the adjacent battery containers together with the bolts and nuts made of an aluminum alloy, the two connection members are bolts and nuts. It is made to be electrically connected via. For this reason, the molten salt batteries that are mechanically firmly connected are electrically connected in series.
Further, since the bolt and nut are insulated from each battery container by a bushing made of Teflon (registered trademark), five positive electrodes and six negative electrodes electrically connected between adjacent molten salt batteries, Electrical insulation from each battery container that is mechanically connected is maintained.
Therefore, it is possible to simultaneously perform mechanically strong connection and electrical connection between adjacent molten salt batteries while maintaining the electrical insulation relationship between the positive electrode and the negative electrode and the battery container.

Moreover, the upper part of the container main body of the battery container is opened in a rectangular shape, and five positive electrodes and six negative electrodes arranged side by side with the opposing direction in the horizontal direction are immersed in a molten salt filled in the battery container.
Therefore, the five positive electrodes and the six negative electrodes stacked outside the battery container can be easily inserted into the container main body from above the opening of the container main body with the stacking direction being the horizontal direction. Moreover, it becomes possible to inject | pour molten salt from the opening of a container main body, and to spread suitably between a positive electrode, a separator, and a negative electrode. Furthermore, since the above-mentioned connecting member is located above the liquid surface of the molten salt, it is possible to reduce the influence of corrosion or the like due to the molten salt.

Furthermore, the direction in which the five positive electrodes and the six negative electrodes are laminated is orthogonal to the direction in which the molten salt batteries are arranged next to each other. That is, the molten salt batteries are arranged in a direction along a surface where the positive electrode and the negative electrode alternately face each other.
Therefore, among the side walls of the battery container having a rectangular parallelepiped shape, the molten salt batteries can be arranged side by side with the side walls located on the short side in a plan view.
In addition, connection tabs for taking out current from each of the positive electrode and the negative electrode are arranged in parallel on both sides in the direction along the surface where the positive electrode and the negative electrode alternately face each other. By aligning the juxtaposed direction of the connecting tabs with the arranging direction of the molten salt batteries, it is possible to shorten the length of the connecting member that connects the connecting tabs and the bolts.

Furthermore, an insertion hole that communicates the space in each battery container of adjacent molten salt batteries with each other at a position above the liquid level of the molten salt is formed in the side wall that is abutted between the battery containers. Further, a bushing made of Teflon (registered trademark) is inserted, and the above-described bolt is inserted into the bushing.
Therefore, battery containers of adjacent molten salt batteries can be fastened with bolts and nuts that are not visible from the outside, and insulation between each battery container and the bolts and nuts can be easily secured.

Furthermore, the connection tab and the connection member, the bolt and the nut, the positive electrode and the negative electrode are made of an aluminum alloy. That is, all the members for connecting between the positive electrode and negative electrode of adjacent molten salt batteries contain the same kind of conductive material as the positive electrode and negative electrode.
Thereby, it becomes possible to suppress the electric corrosion which may occur when the member which connects between a positive electrode and a negative electrode contacts a molten salt.

  Furthermore, since all the members for connecting the positive and negative electrodes of adjacent molten salt batteries and the positive and negative electrodes are made of an aluminum alloy containing 90% by weight or more of aluminum, the corrosion resistance and the deterioration resistance are excellent. ing. In addition, a battery container that is particularly complicated to process can be appropriately processed from an aluminum alloy material.

Furthermore, among two battery containers of adjacent molten salt batteries, a through hole is formed in the lid of the battery container in which a bolt head (bolt head) for fastening each molten salt battery is located, A lead wire connected to the bolt via a washer is inserted into the through hole through an insulating member fitted in the through hole.
Therefore, it is possible to monitor the battery voltage and the charging depth of each of the molten salt batteries arranged in a row by using a lead wire, and when each discharge is performed in an amount corresponding to the magnitude of the charging depth, It becomes possible to make the progress of deterioration of the salt battery uniform.

  In the first embodiment, a maximum of three connection tabs 22, 22, 22 and 42, 42, 42 are welded together to one arm portion 231 and 431 of each of the connection members 23 and 43. When the thickness of 22 and 42 is about 0.1 mm, a maximum of about 10 connection tabs 22, 22,... 22 and 42, 42,. It is possible to weld. Therefore, even when the number of power generation elements is increased to about 10, it is possible to apply the connection members 23 and 43 having a U-shaped plan view used in the first embodiment.

(Modification)
FIG. 7 is a partial top view schematically showing the configuration of the molten salt assembled battery according to the modification of the first embodiment of the present invention. The molten salt battery according to Embodiment 1 shown in FIG. 3 includes five positive electrodes 41, 41,... 41 and six negative electrodes 21, 21,. However, in the molten salt battery according to the modified example, the positive electrode 41, the separator 31, and the negative electrode 21 are provided one by one, and the connection members 23 and 43 are planar. The view is L-shaped. In the modified example, only one set of adjacent molten salt batteries among the four or more adjacent molten salt batteries that are continuously adjacent to each other is shown in a more simplified manner than FIG.

  Each of the connection members 23 and 43 of the first embodiment has a large number of connection tabs 22, 22,... 22 and 42, 42,. However, since each of the connection members 23 and 43 of the modification has one connection tab 22 and 42 to be connected, each of the arm portions 231 and 431 has one each. It ’s enough. If the number of pairs of the positive electrode 41 and the negative electrode 21 is about 10 or less, the connection tabs 22, 22,... 22 and 42, 42,. Is possible. In this case, the front and rear positions of the arm portions 231 and 431 may be changed as appropriate.

<< Embodiment 2 >>
The modification of the first embodiment is a form in which molten salt batteries are arranged in a direction along the surface where the positive electrode 41 and the negative electrode 21 face each other, whereas in the second embodiment, the positive electrode 41 and the negative electrode 21 face each other. This is a form in which molten salt batteries are arranged in a line in the direction.
FIG. 8 is a partial top view schematically showing the configuration of the molten salt assembled battery according to Embodiment 2 of the present invention. FIG. 8 shows only one set of adjacent molten salt batteries among four or more adjacent molten salt batteries that are adjacent to each other. It arrange | positions so that side wall 1C, 1D of a side may be faced | matched. Each molten salt battery includes one positive electrode 41, one separator 31, and one negative electrode 21.

  Through holes 1H and 1H penetrating in the lateral direction (the front-rear direction in the figure) are provided at positions close to the side wall 1A (or one of the positions near the side wall 1B) of the upper portions of the abutted side walls 1C and 1D. Bushings 81 and 81 are fitted into the through holes 1H and 1H from the side walls 1C and 1D, respectively. Of the abutting portions of the side walls 1C and 1D, an O-ring (not shown) is provided between a concave groove (not shown) provided in a portion facing the through holes 1H and 1H and a gap facing the bushings 81 and 81. Is attached. Bolts 51 made of an aluminum alloy are inserted into the bushings 81, 81 from the side wall 1D side through a connection member 23 made of an aluminum alloy. The bolt 51 is screwed onto a nut 52 made of an aluminum alloy via a connection member 43 made of an aluminum alloy on the side wall 1C side.

  In the second embodiment, the joining positions of the connection tabs 42 and 22 with respect to the positive electrode 41 and the negative electrode 21, respectively, are biased in the opposite directions, differing between adjacent molten salt batteries. Specifically, in one molten salt battery shown on the back side in FIG. 8, the connection tab 42 (or 22) made of an aluminum alloy at a position near the side wall 1B (or 1A) of the positive electrode 41 (or the negative electrode 21). In the other molten salt battery shown in FIG. 8 on the front side, the connection tab 42 (or 22) is joined at a position near the side wall 1A (or 1B) of the positive electrode 41 (or the negative electrode 21). To do. Then, the connection tabs 22 and 42 are welded to the connection members 23 and 43, respectively. In this case, the connection members 23 and 43 may be short in the lateral direction of FIG.

  With the above configuration, the side wall 1D of one container body 1 and the side wall 1C of the other container body 1 are fastened by the bolt 51 and the nut 52 via the bushings 81, 81, and the connection members 23, 43 are It is electrically connected via a bolt 51. The bolt 51 and the nut 52 are electrically insulated from the side walls 1C and 1D. On the other hand, connection tabs 22 and 42 are welded to the connection members 23 and 43, respectively, and the connection tabs 22 and 42 are respectively connected to the negative electrode 21 and the positive electrode 41. Therefore, the negative electrode 21 and the positive electrode 41 accommodated in the container main bodies 1 and 1 having the side walls 1C and 1D facing each other are electrically connected, and adjacent molten salt batteries are electrically connected in series. The

  In addition, the same code | symbol is attached | subjected to the location corresponding to Embodiment 1, and the detailed description is abbreviate | omitted.

As described above, according to the second embodiment, the direction in which the positive electrode and the negative electrode face each other coincides with the direction in which the molten salt batteries are arranged next to each other.
Therefore, among the side walls of the battery container having a rectangular parallelepiped shape, the molten salt batteries can be arranged side by side with the side walls located on the long side in a plan view.

(Modification)
FIG. 9 is a partial top view schematically showing the configuration of the molten salt assembled battery according to the modification of the second embodiment of the present invention. In the molten salt assembled battery according to the second embodiment shown in FIG. 8 described above, the side walls 1C and 1D of the adjacent container bodies 1 and 1 are arranged so as to face each other, whereas the molten salt according to the modification is provided. In the salt battery, the side walls 1C and 1C of the adjacent container main bodies 1 and 1 and the side walls 1D and 1D are arranged in a row so as to face each other. In the modification, the direction in which the connection positions of the connection tabs 42 and 22 are biased with respect to the positive electrode 41 and the negative electrode 21 is constant for each molten salt battery, as in the first embodiment and the modification. .

  In the second embodiment, the direction in which the positive electrode 41 and the negative electrode 21 face each other is aligned with the direction in which the molten salt batteries are arranged. However, in the modification, the direction in which the positive electrode 41 and the negative electrode 21 face each other is adjacent to each other. The reverse direction occurs between salt batteries. Thereby, when connecting the positive electrode 41 and the negative electrode 21 with which each adjacent molten salt battery is provided separately, the connection tabs 42 and 22 can be biased to one side intersecting the arrangement direction. The lengths of the connecting members 23 and 43 can be shortened. In this case, the shapes of the connecting members 23 and 43 may be changed as appropriate.

<< Embodiment 3 >>
While Embodiments 1 and 2 are a form in which a plurality of molten salt batteries are electrically connected in series, Embodiment 3 is a form in which a plurality of molten salt batteries are electrically connected in parallel.
FIG. 10 is a partial top view schematically showing the configuration of the molten salt assembled battery according to Embodiment 3 of the present invention. FIG. 10 shows only one set of adjacent molten salt batteries among four or more adjacent molten salt batteries, and each molten salt battery has a length of a container body 1, 1 made of an aluminum alloy. It arrange | positions so that side wall 1C, 1D of a side may be faced | matched. Each molten salt battery includes one positive electrode 41, one separator 31, and one negative electrode 21.

  Through holes 1H and 1H penetrating in the lateral direction (front-rear direction in the figure) are provided at positions near the side wall 1A (or positions near the side wall 1B) of the upper portions of the butted side walls 1C and 1D. Bushings 81 and 81 are fitted into the holes 1H and 1H from the side walls 1C and 1D, respectively. Of the abutting portions of the side walls 1C and 1D, an O-ring (not shown) is provided between a concave groove (not shown) provided in a portion facing the through holes 1H and 1H and a gap facing the bushings 81 and 81. Is attached. Bolts 51 made of an aluminum alloy are inserted into the bushings 81, 81 through connection members 23 (or 43) made of an aluminum alloy. The bolt 51 is screwed into a nut 52 made of an aluminum alloy via a connection member 43 (or 23) on the side wall 1C side.

  The lower end portion of the connection tab 22 made of a rectangular aluminum alloy for taking out current is joined to the upper end portion of the negative electrode 21 on the side close to the side wall 1A. The upper part of the connection tab 22 is welded to the side surface of the arm portion 231 of the connection member 23. The lower end portion of the connection tab 42 made of a rectangular aluminum alloy for taking out current is joined to the upper end portion of the positive electrode 41 on the side close to the side wall 1B. The upper portion of the connection tab 42 is welded to the side surface of the arm portion 431 included in the connection member 43.

  With the above configuration, the side wall 1D of one container main body 1 and the side wall 1C of another container main body 1 are connected to two sets of bolts 51, nuts 52, and the like through two sets of bushings 81, 81, 81, 81, respectively. While being fastened by the bolt 51 and the nut 52, the connection members 23, 23 and 43, 43 are electrically connected via the bolts 51 and 51, respectively. Each bolt 51 and nut 52 are electrically insulated from the side walls 1C and 1D. On the other hand, the connection tabs 22, 22 and 42, 42 are welded to the connection members 23, 23 and 43, 43, respectively. The connection tabs 22, 22 and 42, 42 are respectively connected to the negative electrodes 21, 21 and The positive electrodes 41 and 41 are connected separately. Accordingly, the negative electrodes 21 and 21 and the positive electrodes 41 and 41 accommodated in the container main bodies 1 and 1 having the respective side walls 1C and 1D facing each other are electrically connected to each other, and adjacent molten salt batteries are connected to each other. Are electrically connected in parallel.

In addition, the same code | symbol is attached | subjected to the location corresponding to Embodiment 1, and the detailed description is abbreviate | omitted.

As described above, according to the third embodiment, the connection tab of the positive electrode provided in each of the adjacent molten salt batteries and one bolt made of an aluminum alloy are separately provided by two connection members made of an aluminum conductor. The battery containers of adjacent molten salt batteries are fastened using the one bolt and one nut made of an aluminum alloy. Similarly, the connection tab of the negative electrode provided in each of the adjacent molten salt batteries and other bolts made of aluminum alloy are connected separately by the other two connection members made of aluminum alloy, and the other bolts The battery containers of the adjacent molten salt batteries are fastened using other nuts made of an aluminum alloy. Accordingly, the molten salt batteries can be electrically connected in parallel and mechanically firmly connected.
In addition, since the one bolt and nut and the other bolt and nut are insulated from each battery container, the positive and negative electrodes electrically connected in parallel between adjacent molten salt batteries, a machine It is possible to maintain electrical insulation with each battery container connected to the battery.

  In Embodiments 2 and 3, an example in which one positive electrode 41 and one negative electrode 21 are provided has been described. However, the present invention is not limited to this, and a plurality of positive electrodes 41, 41,. ,... 21 may be provided. In this case, the connection tabs 42, 42,... 42 and 22, 22,... 22 may be welded to the arm portions appropriately provided on the connection members 43 and 23. Moreover, each positive electrode 41 may be wrapped in the separator 31.

<< Embodiment 4 >>
Next, Embodiment 4 in which a bolt and a nut as a fastening member are insulated from the battery case 10 and an insulating seal structure for closing the through hole 1H of the battery case 10 is different from the above embodiment will be described. To do. In addition, since it is the same as that of Embodiment 1 (or 2, 3) except the said insulation seal structure, description is abbreviate | omitted here.

  FIG. 11 is an enlarged cross-sectional view of a connection portion of the molten salt assembled battery in the fourth embodiment. The difference from FIG. 6 is that the bushing 81 and the O-ring 82 in FIG. 6 are not provided. Therefore, in FIG. 11, the concave groove (circumferential groove) for mounting the O-ring is not formed at the edge of the through hole 1H in the side walls 1A and 1B. On the other hand, in the structure of FIG. 11, as parts not shown in FIG. 6, an insulating washer 91 made of, for example, Teflon (registered trademark), a rubber member 92 made of, for example, fluoro rubber, and a rubber member 92 are arranged in the axial direction ( In the figure, there is provided a pressing member 93 made of, for example, an aluminum alloy so as to be wrapped from one end side. These members (91 to 93) constitute an insulating seal member 90 that insulates the bolt 51 and nut 52, which are fastening members, from the battery container 10 and seals the through hole 1H by fastening the bolt 51 and nut 52. ing. One set of insulating seal member 90 is provided for each battery container.

  12A is a cross-sectional view showing the rubber member 92 and the pressing member 93 in a free state before being mounted as shown in FIG. The rubber member 92 and the pressing member 93 are ring-shaped members into which screw parts 51S (FIG. 11) excluding the heads of the bolts 51 are inserted. Further, the pressing member 93 has a peripheral surface portion 93b continuous from the bottom surface portion 93a, thereby covering the rubber member 92 so as to be wrapped from one end side in the axial direction (left-right direction in FIG. 12). Moreover, it is not completely covered, but a part of the rubber member 92 protrudes from the other axial end side.

  When the bolt 51 is passed through the rubber member 92 and the pressing member 93 shown in FIG. 12A and the nut 52 is screwed to fasten the bolt 51 and the nut 52 as shown in FIG. 93 presses the rubber member 92 between the side walls 1A and 1B, respectively. As a result, the rubber member 92 is deformed and bites into the through hole 1H, thereby sealing the through hole 1H as shown in FIG. FIG. 12B is an enlarged sectional view showing the rubber member 92 and the pressing member 93 in the state shown in FIG.

  In FIG. 11, the rubber member 92 biting into the through hole 1H is in close contact with the entire circumference of the inner peripheral surface of the through hole 1H, and also against the peripheral portion 1P of the through hole 1H on the inner surface side of the side walls 1A and 1B. , Close contact with the entire circumference. Further, the rubber member 92 projects to the inner peripheral side due to the deformation, and the inner diameter is slightly reduced (see FIG. 12B). As a result, the rubber member 92 is also in close contact with the outer peripheral surface of the threaded portion 51S of the bolt 51. Accordingly, the gap due to the through hole 1H is completely closed by the rubber member, and excellent sealing performance against liquid and gas can be obtained. Further, since the seals are independent for each through-hole 1H, even if vibration or impact is applied to the container body 1, the seal performance is not easily impaired.

  Further, the connecting members 23 and 43 are insulated from the side walls 1A and 1B by the insulating washer 91, respectively. Note that a gap is formed between the inner peripheral surface of the pressing member 93 and the screw portion 51S of the bolt 51, and is insulated from the screw portion 51S.

  In the structure of FIG. 6, members corresponding to the insulating seal member 90 are a bushing 81 and an O-ring 82. In the structure of FIG. 6, the bushing 81 is mainly for insulation, and the sealing performance for preventing leakage of liquid and gas from the pair of left and right through holes 1 </ b> H depends on one O-ring 82. In this case, when vibration or impact is applied to the container body 1, a minute shift or gap is generated between the pair of container bodies 1, and the sealing performance may be slightly impaired. In that respect, as described above, the insulating seal structure of FIG. 11 is less likely to deteriorate the sealing performance even if vibration or impact is applied to the container body 1.

In the fourth embodiment, the material of the washer 91 may be nylon or other resin. The material of the rubber member 92 may be silicon rubber, for example.
Bolts (including screws) and nuts are typical examples of fastening members, but other than that, for example, fastening members in which nuts are screwed to both ends of a bar screw may be used, or rivets may be used. Is possible.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 Container body 1A, 1B Side wall 1H Through hole (through hole in side wall)
10 Battery container 21, 21, ... 21 Negative electrode 22, 22, ... 22 Connection tab 23 Connection member 31, 31, ... 31 Separator 41, 41, ... 41 Positive electrode 42, 42, ... 42 Connection tab 43 Connection member 51 Bolt 52, 52 Nut 54 Lead wire (conductive wire)
6 Molten salt 7 Lid 7B Through-hole (through-hole of lid)
81 Bushing (insulating bushing)
90 (91, 92, 93) Insulating seal member 91 Washer 92 Rubber member 93 Holding member

Claims (10)

One or a plurality of positive electrodes and negative electrodes are housed in a battery container made of a conductor, and a plurality of rows of molten salt batteries configured to take out current from connection tabs of each of the positive electrodes and the negative electrodes are connected in series. In the molten salt assembled battery,
Using bolts and nuts made of conductors, the battery containers of adjacent molten salt batteries are fastened together,
The two adjacent connection members that electrically connect the bolts to the connection tabs of the positive and negative electrodes provided separately by the adjacent molten salt batteries,
The bolt and nut are insulated from each battery container of the adjacent molten salt battery. The battery container has a container body having an opening in the upper part, and a lid for sealing the opening of the container body,
The positive electrode and the negative electrode are juxtaposed in the lateral direction,
The molten salt assembled battery according to claim 1, wherein the positive electrode and the negative electrode are immersed in a molten salt.   The molten salt assembled battery according to claim 2, wherein the parallel arrangement direction of the positive electrode and the negative electrode is a direction intersecting with the arrangement direction of the molten salt batteries. The battery container of the adjacent molten salt battery has a through hole that communicates at a position above the liquid surface of the molten salt,
The bolt is inserted through the through hole,
The molten salt assembled battery according to claim 2, further comprising an insulating bushing that insulates and supports the bolt and the nut in the through hole.   The molten salt assembled battery according to any one of claims 1 to 4, wherein the connection tab, the connection member, the bolt, and the nut include a conductive material of the same type as the positive electrode and the negative electrode.   The molten salt assembled battery according to claim 5, wherein the conductive material is an alloy containing 90% by weight or more of aluminum. Comprising a conducting wire connected to the bolt;
The lead wire is inserted into and insulated from a through hole formed in a lid of one battery container of the adjacent molten salt battery. The molten salt assembled battery according to any one of the above. One or a plurality of positive and negative electrodes are accommodated in a battery container made of a conductor, and a plurality of molten salt batteries arranged to take out current from connection tabs of each of the positive and negative electrodes are connected in parallel. In the molten salt assembled battery,
Using at least two sets of bolts and nuts made of a conductor, battery containers of adjacent molten salt batteries are fastened together,
Two connecting members that electrically connect one bolt to each positive electrode provided in each of the adjacent molten salt batteries;
Two other connecting members that electrically connect other bolts to the connection tabs of the negative electrodes provided in the adjacent molten salt batteries, respectively,
The bolt and nut are insulated from each battery container of the adjacent molten salt battery. A molten salt assembled battery in which a plurality of battery containers for molten salt batteries containing electrodes are connected, and the electrodes of each battery container are electrically connected in series or in parallel with each other,
A fastening member made of a conductor and inserted into a hole formed in the conductive side wall of each battery container of adjacent molten salt batteries, and fastening the battery containers,
Connection members that electrically connect the electrodes provided separately by the adjacent molten salt batteries to one end and the other end of the fastening member, respectively,
A molten salt assembled battery comprising: an insulating seal member that insulates the fastening member from each battery container of the adjacent molten salt battery and seals the hole by fastening of the fastening member. The fastening members are bolts and nuts,
The insulating seal member is provided for each of the battery containers,
A ring-shaped rubber member for interpolating a portion excluding the head of the bolt;
A pressing member that covers the rubber member so as to wrap from one end side in the axial direction, and a part of the rubber member protrudes from the other end side in the axial direction;
An insulating washer interposed between the pressing member and the connecting member;
The molten salt assembled battery according to claim 9, wherein when the fastening member is fastened, the pressing member presses the rubber member to bite into the hole, thereby sealing the hole.