JP2019074246A - Heat storage device - Google Patents

Abstract

To provide a heat storage device in which crystallization starts and heat can be extracted surely even in the case where a heat storage material is held at high temperature in a liquid state and then voltage is applied in a super cooling state.SOLUTION: A heat storage device includes: a heat storage material whose main component is sodium acetate trihydrate; and a pair of electrodes 13 at least one of which includes a silver electrode including silver or silver alloy. The electrode 13 has an oxide film 17 which includes silver at least at part of a surface 16, and the electrode 13 comes into contact with the heat storage material at least via the oxide film 17. The oxide film 17 has a hole part 18 recessed toward the electrode surface, and in the hole part 18, sodium acetate anhydride 19 exists.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a heat storage device.

  When thermal energy is used for industrial use or household use, the amount or timing of use is often different with respect to the amount or time of generation of thermal energy, and thermal energy is temporarily temporarily used to effectively utilize all the generated heat. It has been proposed to use a medium for storing energy, a so-called heat storage material.

  Thermal storage materials are roughly classified into sensible heat storage materials and latent heat storage materials. The latent heat storage material is a heat storage material that utilizes a phase change of a substance. The latent heat storage material has an advantage that the heat extraction temperature is stable because the heat storage density is high and the temperature at the time of phase change is constant as compared with the sensible heat storage material. When heat storage is performed using a latent heat storage material, the latent heat storage material is heated to be in a liquid state at the time of heat storage. After that, the liquid state is kept in a state of being kept warm so that the liquid state is maintained. The heat stored in the held latent heat storage can be taken out by crystallizing the latent heat storage material when necessary.

  Among the latent heat storage materials, sodium acetate trihydrate is known as a substance that can store heat efficiently with a small capacity because it has a relatively large amount of latent heat of melting. Moreover, since sodium acetate trihydrate does not show toxicity and is a safe substance, various applications are considered. For example, Patent Document 1 discloses a system using sodium acetate trihydrate as a heat storage material.

  It is known that sodium acetate trihydrate melts at the melting point, but does not solidify even below the melting point at the time of solidification, i.e., so-called supercooling state. Then, after making the heat storage material containing sodium acetate trihydrate into a liquid state by heating, keeping heat storage material in a supercooling state and storing heat is examined. At the time of heat release, the heat stored in the heat storage material can be taken out by releasing the supercooling state of the heat storage material containing sodium acetate trihydrate.

  An electrode mainly composed of silver that applies a voltage to a heat storage material in a subcooling state is known as a means for releasing the subcooling state (see, for example, Patent Document 2).

  Further, in Patent Document 3, a sealed container, a latent heat storage material for causing a supercooling phenomenon sealed in the sealed container, a heating element for heating the latent heat storage material, and application to a voltage are provided in the sealed container. A thermal storage device is disclosed which comprises: an electrode for stimulating the latent heat storage material. In the heat storage device of this configuration, the heat generating element is energized to heat and melt the latent heat storage material, thereby storing heat and causing a supercooling phenomenon, and applying a voltage to the latent heat storage material at any time to stimulate And release the subcooling of the latent heat storage material with this stimulus to release latent heat. Thereby, heat can be taken out at the required time.

JP 2008-20177 A Japanese Patent Application Laid-Open No. 61-204293 Japanese Utility Model Publication No. 62-135392

  However, in the conventional configuration, even if the heat storage material containing sodium acetate trihydrate is heated to be in a liquid state in the heat storage process, if the heat storage material is held at a temperature above the melting point for a certain period of time, then supercooling In the state, even if a voltage is applied using an electrode containing silver as a main component (hereinafter referred to as a silver electrode), crystallization of the heat storage material is not started, and the stored heat can not be extracted. .

  The present disclosure solves the above-mentioned conventional problems, and even when the heat storage material containing sodium acetate trihydrate is held in the liquid state at a temperature above the melting point, voltage application in the subsequent supercooling state is performed. It is an object of the present invention to provide a heat storage device capable of starting crystallization and reliably extracting stored heat.

  In order to solve the above-mentioned conventional problems, the heat storage device of the present disclosure comprises at least one of a heat storage material containing sodium acetate trihydrate, and a silver electrode in contact with the heat storage material and containing silver or a silver alloy. A thermal storage device comprising a pair of electrodes, wherein the electrode has an oxide film containing silver and bromine on at least a part of the surface, and is in contact with the thermal storage material through at least the oxide film The oxide film has a hole having a shape which is recessed toward the surface, and sodium acetate anhydride is attached to the hole.

  According to the technology of the present disclosure, even when the heat storage material containing sodium acetate trihydrate is in a liquid state by heating and then held at a temperature above the melting point, a voltage is applied in the subsequent supercooling state. By doing this, crystallization of the heat storage material can be started, and the stored heat can be reliably taken out.

Schematic of a heat storage device in an embodiment of the present disclosure Schematic of the electrode surface of the heat storage device in the embodiment of the present disclosure

<Findings based on the study of the present inventors>
As described above, the heat storage device using sodium acetate trihydrate as the heat storage material shown in Patent Document 1 heats the heat storage material to be in a liquid state, and then stores the heat storage material in a supercooled state to store heat. It is known that the heat stored in the heat storage material can be taken out by releasing the subcooling state of the heat storage material at the time of heat release. Then, if a voltage is applied to the heat storage material in the supercooled state using a silver electrode as one of the means for releasing the supercooling state, nucleation is surely recognized, that is, the supercooling is canceled. Is disclosed in Patent Document 2. However, in this configuration, when the heat storage material is heated to be in a liquid state in the heat storage process and then held at a high temperature, that is, a temperature higher than the melting point, for a certain period of time, The inventors found that even if a voltage is applied using a typical silver electrode, there is a problem that the subcooling is not released, that is, the heat can not be extracted. In this regard, the present inventors repeated analysis, and when crystallization is started when a voltage is applied when the heat storage material containing sodium acetate trihydrate as a main component is in a state of supercooling, immediately before the application of voltage. In the heat storage material of the present invention, attention is focused on the presence of nano-sized fine particles, that is, clusters derived from sodium acetate hydrate. And when crystallization did not occur even if it applied a voltage using a silver electrode, it discovered that this thermal storage material in front of a voltage application did not have this cluster. From this, it can be sufficiently predicted that the cluster functions as an origin of crystallization, that is, a crystal nucleus. Therefore, when exposed to a situation in which this cluster disappears before the subcooling state, the crystal nucleus does not exist even if a voltage is applied using the silver electrode in the subcooling state, so that crystals do not exist. Does not occur. Since this cluster is derived from sodium acetate hydrate, if it is held at a temperature higher than the melting point of sodium acetate hydrate, the cluster is considered to melt and disappear if the holding time is long. The melting point of sodium acetate trihydrate is 58 ° C., but according to the experiments of the inventors, when the heat storage material in which the presence of clusters is confirmed in the liquid state is held at 90 ° C. for one hour, for example In this condition, it is confirmed that the clusters disappear completely, because no crystallization occurred even if a voltage was applied using a silver electrode in the subsequent supercooling state. There is.

  On the other hand, the present inventors, even if exposed to the condition that the clusters disappear at high temperature, if the heat storage material has a configuration that functions as a crystal nucleus instead of the clusters, crystallization occurs by voltage application. I found that I could do it. And in such a heat storage material, a solid material having a temperature sufficiently higher than the temperature at which clusters disappear, ie, the melting point of sodium acetate hydrate, can contribute to nucleation of the heat storage material. It has been found that a configuration as present in is desirable. That is, even if the heat storage material is exposed to a high temperature at which the cluster disappears, this material can be present as a solid at least as long as it is below the melting point of this solid material, so it is fully expected to function as a crystal nucleus it can.

  Based on the above, the present inventors are in a supercooled state even when the heat storage material containing sodium acetate trihydrate as a main component is held in a liquid state at a high temperature above the melting point and the clusters melt and disappear. A heat storage device capable of generating crystallization by voltage application and extracting the stored heat was examined.

  One embodiment of the present disclosure includes a heat storage material comprising sodium hydroxide trihydrate-containing heat storage material, and a pair of electrodes in contact with the heat storage material and having at least one silver electrode containing silver or a silver alloy. In the apparatus, the silver electrode has an oxide film containing silver and bromine on at least a part of the surface, and is in contact with the heat storage material via at least the oxide film, and the oxide film is provided on the surface It has a hole having a concave shape, and sodium acetate anhydride is attached to the hole.

  According to the present disclosure, even when the heat storage material in the liquid state is held under the condition that the sodium acetate hydrate salt cluster disappears, crystallization of the heat storage material is started, and the stored heat is reliably extracted. it can. From this, when a voltage is applied, sodium acetate anhydride, which is a solid substance having a melting point higher than that of sodium acetate hydrate, adheres to and is present in the pores of the oxide film on the surface of the silver electrode. It is considered to function as a crystal nucleus.

Embodiment
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present invention is not limited by the embodiment.

  FIG. 1 is a schematic view of a heat storage device according to an embodiment of the present disclosure.

  In FIG. 1, the heat storage device 10 includes a heat storage tank 11 filled with a heat storage material 12, a pair of electrodes 13, a DC power supply 14, and a switch 15.

  The heat storage tank 11 is kept warm by a heat insulating material. An example of a thermal insulation is glass wool. The heat storage tank 11 stores the heat storage material 12 inside. In the present embodiment, the heat storage material 12 contains sodium acetate trihydrate (melting point: 58 ° C.) as a main component. As an example, the heat storage material 12 contains 65 to 100% by weight of sodium acetate trihydrate.

The heat storage material 12 may contain an additive. Additives include, for example, supercooling release aids, viscosity modifiers, foam stabilizers, antioxidants, defoamers, abrasive grains, fillers, pigments, dyes, colorants, thickeners, surfactants, Known materials such as flame retardants, plasticizers, lubricants, antistatic agents, heat stabilizers, tackifiers, curing catalysts, stabilizers, silane coupling agents and waxes can be used. These additives are not particularly limited in their types and amounts, as long as the purpose of the present disclosure is not impaired.

  As shown in FIG. 1, the pair of electrodes 13 is electrically connected to the DC power supply 14 through the wiring and the switch 15.

  The pair of electrodes 13 is disposed to be in contact with the heat storage material 12, and the distance between the parts in contact with the heat storage material 12 is not particularly limited. The said distance is 1 mm-30 mm, for example.

  When at least one of the pair of electrodes 13 contains a silver alloy, the silver alloy is present in at least a portion of the surface 16 of the pair of electrodes 13 in contact with the heat storage material 12. Here, the silver alloy is, for example, a silver-palladium alloy or a silver-copper alloy. The pair of electrodes 13 may be entirely formed of silver or a silver alloy, or may be formed on a main body made of another metal such as stainless steel or copper, and on the main body. It may be provided with the formed silver or silver alloy. Further, the shape of the pair of electrodes 13 is not particularly limited, and is, for example, plate-like or wire-like.

  FIG. 2 is a schematic view showing a part of the surface of the electrode 13. As shown in FIG. 2, an oxide film 17 containing silver and bromine is formed on a part of the surface 16 of the electrode containing a silver alloy among the pair of electrodes 13. The thickness L of the oxide film 17 is approximately several tens of microns. This oxide film 17 has pores 18, and sodium acetate anhydride 19 is present in the pores 18. The size D of the hole 18 is typically about several microns at the largest opening. Sodium acetate anhydrous 19 (melting point: 324 ° C.) has a melting point sufficiently higher than sodium acetate trihydrate (melting point: 58 ° C.). Therefore, when the heat storage material in the liquid state is held at a high temperature above the melting point of sodium acetate trihydrate, the sodium acetate hydrate salt cluster melts and disappears, but the melting point of sodium acetate anhydride If it is less than this, sodium acetate anhydride 19 is present at the surface 16 of the electrode 13 without melting. As a result, even when the heat storage material 12 is held under the condition that the sodium acetate hydrate salt cluster disappears, the sodium acetate anhydride 19 functions as a crystal nucleus by applying a voltage, so the heat storage material 12 is Crystallization can start, and the stored heat can be taken out.

  Here, a method of forming an oxide film 17 containing silver and bromine on a part of the surface 16 of the pair of electrodes 13 containing a silver alloy in at least one side will be described.

  An aqueous solution containing potassium bromide is prepared, and a voltage is applied to the pair of electrodes 13 in contact with the aqueous solution, whereby an oxide film 17 containing silver and bromine is formed on part of the surface 16 of the electrode 13. As the bromide ions present in the potassium bromide aqueous solution attack the surface of the formed oxide film 17, pitting proceeds to form pores 18.

  Next, a method for introducing sodium acetate anhydride 19 into the pores 18 of the oxide film 17 containing silver and bromine will be described.

  The electrode 13 on which the oxide film 17 having the holes 18 is formed is immersed in a sodium acetate aqueous solution so that the holes 18 are immersed, and left at a predetermined temperature for a predetermined time. As a result, the pores 18 of the oxide film 17 are impregnated with the sodium acetate aqueous solution. Thereafter, by cooling the aqueous sodium acetate solution, sodium acetate anhydride 19 precipitates. By this operation, sodium acetate anhydride 19 can be introduced into the pores 18 of the oxide film 17.

  In the step of introducing sodium acetate anhydride 19 into pores 18, after sodium acetate trihydrate is held by pores such as rubbing, sodium acetate trihydrate in pores 18 is heated by heating. The product may be dehydrated to introduce sodium acetate anhydride 19 into the pores 18. Alternatively, the sodium acetate anhydride 19 may be directly rubbed into the pores 18 of the oxide film 17.

  The heat storage device 10 according to the present embodiment may include a plurality of heat storage tanks 11. Each heat storage tank 11 includes a pair of electrodes 13 in contact with each heat storage material 12, and the plurality of heat storage tanks 11 may be electrically connected in parallel to the DC power supply 14.

  Further, the power supply in the heat storage device 10 is not limited to the DC power supply 14, and each of the pair of electrodes 13 may be electrically connected to the AC power supply by wiring.

  Next, how to use the heat storage device 10 will be described.

  First, the heat storage material 12 in the liquid state is cooled and brought into the subcooling state. In this way, the latent heat is stored in sodium acetate trihydrate.

  Thereafter, a voltage is applied to the pair of electrodes 13 to crystallize the heat storage material 12 in the subcooled state. As a result, the heat storage material 12 releases heat. That is, latent heat is taken out.

  As described above, after the heat storage material 12 releases heat, the heat storage device 10 is heated at a temperature above the melting point for repeated use. Thus, the crystallized sodium acetate trihydrate melts. Even if the heat storage material 12 is melted to be in a liquid state and the heat storage material 12 is heated at a temperature of 90 ° C. or more, the sodium acetate anhydride 19 is held on the surface 16 of the electrode 13. The sodium acetate anhydride 19 functions as a crystal nucleus, and crystallization of the heat storage material 12 is started again.

  In the present specification, even if the heat storage material is held in a liquid state at a high temperature (a temperature higher than the melting point of sodium acetate hydrate salt) to the extent that clusters disappear, it can be crystallized in the supercooled state There is. On the other hand, since the heat storage material containing sodium acetate trihydrate as the main component is a mixture of sodium acetate and water, it can not be evaporated and can not maintain its liquid state when heated to a predetermined temperature (for example, 123 ° C.) or higher , Will not function as a heat storage material. Therefore, the heat storage material mainly composed of sodium acetate trihydrate can be left as it is in the atmosphere above the melting point of sodium acetate anhydride when storing heat in the heat storage material as a general method of use, sodium acetate anhydride It is not used by adding thermal energy more than the melting point of For this reason, in the present specification, the condition for keeping the temperature high enough to eliminate the clusters is substantially higher than the melting point of sodium acetate anhydride, which is a temperature sufficiently higher than the melting point of sodium acetate hydrate. Low temperature shall be included.

  Next, the embodiment will be more specifically described by way of examples. The present invention is not limited by these examples.

Example 1
A pair of wire-like silver electrodes (purity 99.9%) having a diameter of 1.5 mm and a length of 65 mm were energized for 2 hours at a direct current voltage of +1 V in a 1 wt% aqueous solution of potassium bromide at room temperature. After this, current was supplied for 2 hours with a direct current voltage of -1 V. As a result, an oxide film was formed on the surface of both of the pair of silver electrodes. The observation of the fine structure of the oxide film and the elemental analysis were carried out using a scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation). As a result, it was confirmed that there were pores in the surface of the oxide film. In addition, silver and bromine were detected from the oxide film surface. It is considered that pitting corrosion progresses by attack of bromide ions on the oxide film surface generated by the electric current treatment, and a hole is formed.

  The pair of silver electrodes on which the oxide film formed as described above was formed was immersed in an aqueous solution of 65 wt% of sodium acetate and allowed to stand in an atmosphere of 70 ° C. for 2 hours. Thereby, the pores of the oxide film can be impregnated with an aqueous solution of sodium acetate. Thereafter, the sodium acetate aqueous solution was cooled to precipitate sodium acetate anhydride in the pores.

  Next, a 60 cc glass sample bottle is prepared as a heat storage tank, 28.8 g of sodium acetate and 23.3 g of water are added as a heat storage material to this sample bottle and mixed, and the acetic acid prepared above is further prepared A pair of silver electrodes holding sodium anhydride was immersed in the heat storage material for about 5 mm, and the sample bottle was covered, and the heat storage device according to Example 1 was manufactured.

  The heat storage material in the sample bottle was completely melted in the atmosphere of 70 ° C. to be in a liquid state, and then left in the atmosphere of 90 ° C. for 1 hour.

  After that, it was allowed to cool to room temperature to be in a supercooled state, and when a DC voltage of 2 V was applied for 2 minutes, it was visually observed whether the heat storage material was crystallized. In addition, five samples produced by the same method were prepared for evaluation.

  Table 1 shows the results. The fractional molecules included in Table 1 are the number of samples in which the heat storage material has crystallized. Also, the denominator of the fractions included in Table 1 is the total number of samples (ie, five).

  As shown in Table 1, even when left at 90 ° C. for 1 hour, application of a voltage confirmed that all five samples were crystallized.

Comparative Example 1
A heat storage device according to Comparative Example 1 was produced in the same manner as Example 1, except that the step of forming the oxide film on the surface of the silver electrode and the step of introducing sodium acetate anhydride were omitted.

  The heat storage material in the sample bottle was completely melted in the atmosphere of 70 ° C. to be in a liquid state, and then left in the atmosphere of 90 ° C. for 1 hour.

Thereafter, the resultant was allowed to cool to room temperature to be in a supercooled state, and a crystallization experiment by voltage application was performed in the same manner as in Example 1. The results are shown in Table 1.

  As shown in Table 1, all five samples did not crystallize. As described above, it can be seen that the effect can not be obtained if no pores are formed in the oxide film and the step of introducing sodium acetate anhydride is omitted.

Comparative Example 2
A heat storage device according to Comparative Example 2 was produced in the same manner as Example 1, except that the step of forming the oxide film on the surface of the silver electrode was omitted. In this case, no hole exists in the silver electrode surface.

  The heat storage material in the sample bottle was completely melted in the atmosphere of 70 ° C. to be in a liquid state, and then left in the atmosphere of 90 ° C. for 1 hour.

  Thereafter, the resultant was allowed to cool to room temperature to be in a supercooled state, and a crystallization experiment by voltage application was performed in the same manner as in Example 1. The results are shown in Table 1.

  As shown in Table 1, all five samples did not crystallize. Thus, it can be seen that when the oxide film is not formed, the effect can not be obtained even if the step of introducing sodium acetate anhydride is performed.

Comparative Example 3
A heat storage apparatus according to Comparative Example 3 was produced in the same manner as Example 1, except that the step of introducing sodium acetate anhydride was omitted.

  The heat storage material in the sample bottle was completely melted in the atmosphere of 70 ° C. to be in a liquid state, and then left in the atmosphere of 90 ° C. for 1 hour.

  Thereafter, the resultant was allowed to cool to room temperature to be in a supercooled state, and a crystallization experiment by voltage application was performed in the same manner as in Example 1. The results are shown in Table 1.

  As shown in Table 1, all five samples did not crystallize. As described above, it can be understood that even when the pores are formed in the oxide film, the effect can not be obtained if the step of introducing sodium acetate anhydride is omitted.

Comparative Example 4
A pair of wire-like silver electrodes (purity 99.9%) with a diameter of 1.5 mm and a length of 65 mm were energized for 0.5 hours with a direct voltage of +0.6 V in a 1 wt% aqueous solution of potassium bromide at room temperature . After this, current was further applied for 0.5 hours with a direct current voltage of -0.6V. As a result, an oxide film was formed on the surface of both silver electrodes. According to the same method as in Example 1, the observation of the microstructure of the oxide film and the elemental analysis were carried out. As a result, the presence of pores was not confirmed on the surface of the oxide film. In addition, silver was detected from the oxide film, but no bromine was detected. Since the value of the applied voltage is low and the application time is short, it is considered that pitting corrosion by bromide ions does not progress and holes are not formed in the oxide film as compared with Example 1.

  A heat storage device according to Comparative Example 4 was produced in the same manner as Example 1, except that the pair of silver electrodes on which the oxide film produced under the above conditions was formed was used.

  The heat storage material in the sample bottle was completely melted in the atmosphere of 70 ° C. to be in a liquid state, and then left in the atmosphere of 90 ° C. for 1 hour.

  Thereafter, the resultant was allowed to cool to room temperature to be in a supercooled state, and a crystallization experiment by voltage application was performed in the same manner as in Example 1. The results are shown in Table 1.

  As shown in Table 1, only one was crystallized by applying a voltage. As described above, even when the oxide film is formed, when the pores are not formed on the surface of the oxide film, the crystallization rate is low even if the step of introducing sodium acetate anhydride is performed, and almost no effect is obtained. I understand.

Comparative Example 5
A 60 cc glass sample bottle is prepared as a heat storage tank, and the same method as Comparative Example 1 is used except that 34.0 g of sodium acetate and 18.3 g of water as a heat storage material are added to this sample bottle and mixed. The heat storage device according to Comparative Example 5 was manufactured. In the heat storage material prepared with sodium acetate and water at this ratio, sodium acetate anhydride is dispersed in the heat storage material in the supercooled state.

  The heat storage material in the sample bottle was completely melted in the atmosphere of 70 ° C. to be in a liquid state, and then left in the atmosphere of 90 ° C. for 1 hour.

  Thereafter, the resultant was allowed to cool to room temperature to be in a supercooled state, and a crystallization experiment by voltage application was performed in the same manner as in Example 1. The results are shown in Table 1.

  As shown in Table 1, all five samples did not crystallize. Thus, it can be seen that even if sodium acetate anhydride is dispersed in the heat storage material, no oxide film is formed, and further, if the step of introducing sodium acetate anhydride is omitted, the effect can not be obtained.

Comparative Example 6
A 60 cc glass sample bottle is prepared as a heat storage tank, and the same method as Comparative Example 3 is used except that 34.0 g of sodium acetate and 18.3 g of water as a heat storage material are added to this sample bottle and mixed. The heat storage device according to Comparative Example 6 was manufactured. As in Comparative Example 5, in the heat storage material prepared with sodium acetate and water in this ratio, sodium acetate anhydride is dispersed in the heat storage material in the supercooled state.

  The heat storage material in the sample bottle was completely melted in the atmosphere of 70 ° C. to be in a liquid state, and then left in the atmosphere of 90 ° C. for 1 hour.

  Thereafter, the resultant was allowed to cool to room temperature to be in a supercooled state, and a crystallization experiment by voltage application was performed in the same manner as in Example 1. The results are shown in Table 1.

  As shown in Table 1, all five samples did not crystallize. As described above, it can be understood that the effect can not be obtained if the step of introducing sodium acetate anhydride is omitted even if the pores are formed in the oxide film and the sodium acetate anhydride is dispersed in the heat storage material.

  From the above results, by forming an oxide film containing silver and bromine having pores on the surface of the silver electrode and introducing sodium acetate anhydride into the pores, the heat storage material is hydrated with sodium acetate in a liquid state. Even in the case where the salt clusters are left (for example, at 90 ° C. for one hour), crystallization of the heat storage material is started by applying a voltage, and heat can be extracted.

As described above, according to the heat storage device according to the present disclosure, even when the heat storage material is held at high temperature in the liquid state, crystallization of the heat storage material can be started by voltage application in the subsequent supercooling state. It will be possible to take out heat reliably.

  As one example, the heat storage device according to the present disclosure is attached to a vehicle equipped with an engine that drives wheels. The heat released from the heat storage material is used to warm up an internal combustion engine such as an engine provided in a vehicle. Also, as an example, the heat storage device according to the present disclosure may be attached to a boiler, an air conditioner or a water heater.

DESCRIPTION OF SYMBOLS 10 thermal storage apparatus 11 thermal storage tank 12 thermal storage material 13 electrode 14 DC power supply 15 switch 16 surface 17 oxide film 18 hole part 19 sodium acetate anhydride

Claims (1)

A heat storage material containing sodium acetate trihydrate,
A pair of electrodes in contact with the heat storage material and having at least one silver electrode containing silver or a silver alloy;
A heat storage device provided with
The silver electrode is
Having an oxide film containing silver and bromine on at least a part of the surface, and
Contact with the heat storage material through at least the oxide film,
The oxide film is
It has a hole having a concave shape toward the surface,
In the holes,
Anhydrous sodium acetate is attached,
Heat storage device.

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