Energy storage device

Abstract

To provide an energy storage device capable of efficiently utilizing energy.SOLUTION: A container 10a in an energy storage device 1, which generates heat through a chemical reaction of a heat storage material 3 stored inside the container 10a, is a double-walled container 10a having an inside wall 111 and an outside wall 112. A pair of containers 10 consists of a heat generation side container 11 in which the heat storage material 3 generates heat, and a regeneration side container 12 in which the heat storage material 3 used for heat generation is regenerated. The pair of containers 10 is connected by a pipe 9 provided in an ejector 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an energy storage device. [Background technology]

[0002] Solar and wind power generation have been known as renewable energy sources for curbing global warming. Since it can be difficult to stabilize the power supply of renewable energy, various types of batteries are used to store energy. Energy storage devices that use chemical heat storage, which utilizes the heat of chemical reactions, are known for repeatedly regenerating energy. To improve the chemical reaction and thermal efficiency, it has been proposed to hold a heat storage material inside the container and place the container after the heat dissipation reaction in a passage that has been depressurized using a vacuum pump or the like (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-118315 Summary of the Invention [Problem to be solved by the invention]

[0004] Using a vacuum pump requires additional energy. In addition, with the technology disclosed in Patent Document 1, the entire vessel is placed in a passage under reduced pressure, making it difficult to make each reaction efficient. Thus, there is a problem in that energy is not used efficiently. [Means for solving the problem]

[0005] (1) The present invention relates to an energy storage device (e.g., energy storage device 1) that generates heat through a chemical reaction of a heat storage material (e.g., heat storage material 3) stored inside a container (e.g., container 10a), in which the container is configured with a double wall having an inner wall (e.g., inner wall 111) and an outer wall (e.g., outer wall 112), and a pair of containers (e.g., a pair of containers 10) are configured by a heat generation side container (e.g., heat generation side container 11) in which the heat storage material generates heat, and a regeneration side container (e.g., regeneration side container 12) in which the heat storage material used for heat generation is regenerated, and the pair of containers are connected by a pipe (e.g., pipe 9) provided with an ejector (e.g., ejector 4).

[0006] (2) It is preferable that the device has a water vapor flow path (e.g., water vapor flow path 43) through which the water vapor generated in the heat generation side container flows and in which the ejector is provided, and a negative pressure first flow path (e.g., negative pressure first flow path 41) that is connected from the ejector to the inside of the regeneration side container, and that the negative pressure generated by the Venturi effect of the ejector sucks air inside the regeneration side container through the negative pressure first flow path to reduce the pressure.

[0007] (3) It is preferable that the system has a steam flow path through which the steam generated in the heat-generating container flows and in which the ejector is provided, a check valve (e.g., check valve 45) located near the ejector, and a negative pressure second flow path (e.g., negative pressure second flow path 42) connected from the ejector via the check valve between the inner wall and the outer wall of each of the pair of containers, and that the negative pressure generated by the Venturi effect of the ejector sucks air inside the double walls of the containers through the negative pressure second flow path to reduce the pressure.

[0008] (4) It is preferable that the heat storage material is an alkaline earth metal, the heat generation side container is supplied with water, causing the heat storage material to generate heat, the regeneration side container is heated, the hydroxide of the alkaline earth metal is oxidized, and the heat storage material is regenerated, the heat generation side container and the regeneration side container are connected, and a regeneration steam flow path (e.g., regeneration steam flow path 44) through which steam generated from the regeneration side container flows and in which the ejector is provided is provided, and the negative pressure generated by the Venturi effect of the ejector causes steam to be sucked from the regeneration side container to the heat generation side container and supplied to the heat generation side container.

[0009] (5) It is preferable that the heat storage material is a metal oxide that reacts with water, and that the pair of containers are switched between the heat generation container and the regeneration container so that their roles are alternated between heating and supplying water.

[0010] (6) Each of the pair of containers has a water pipe section (e.g., water pipe section 5) through which water or hot water and steam can flow, and in the regeneration side container, it is preferable that water is not supplied to the water pipe section during regeneration of the heat storage material, but the hot water or steam in the water pipe section is supplied to the water pipe section of the heat generation side container.

[0011] (7) The method for manufacturing an energy storage device according to (1) or (2) relates to a method for manufacturing an energy storage device, in which the inner wall and the outer wall of the double wall are joined together under atmospheric pressure. [Effects of the Invention]

[0012] According to the above (1), the heat generation side container and the regeneration side container are connected by a pipe equipped with an ejector, so when depressurizing the regeneration side container, the steam flow generated from the heat generation side container can be used to depressurize the regeneration side container. This eliminates the need for an electric vacuum pump or the like, making it inexpensive and trouble-free, and allowing the regeneration side container to be depressurized easily. Furthermore, depressurizing the regeneration side container encourages chemical reactions in one direction, promoting oxidation and reducing the energy required to regenerate the heat storage material.

[0013] According to (2) above, the pressure in the regeneration side container can be reduced by the negative pressure caused by the Venturi effect of the ejector, so there is no need for an electric vacuum pump or the like, and since it is inexpensive and does not break down, the pressure in the regeneration side container can be reduced easily.

[0014] According to the above (3), the pressure between the inner and outer walls can be reduced by the negative pressure caused by the Venturi effect of the ejector 4, so an electric vacuum pump or the like is not required, and it is inexpensive and does not break down, so the pressure in the regeneration side container can be easily reduced. In addition, since the pressure between the double walls can be reduced and maintained in a nearly vacuum state, the insulation properties are high and the thermal efficiency is good. Therefore, the insulation material for the pair of containers 10 is not required, which makes recycling easier and reduces the environmental burden.

[0015] According to the above (4), the water vapor generated by the endothermic reaction of the heat storage material 3 in the regeneration-side container 12 is decompressed and sucked in by the ejector 4. Because the water vapor generated during the regeneration of the heat storage material 3 is discharged to the outside of the regeneration-side container 12, the thermal energy required for regeneration is reduced and the temperature required for regeneration is also lowered. In addition, the time required for regeneration can be shortened. Furthermore, because the air and water vapor inside the regeneration-side container 12 are decompressed by the ejector 4, the heat loss of the heated regeneration-side container 12 is reduced.

[0016] According to (5) above, by alternately switching between the heat generation side container and the regeneration side container, it becomes possible to continuously regenerate and store energy.

[0017] According to (6) above, the water in the water pipe section heated during regeneration turns into steam and is supplied to the water pipe section 5 of the heat-generating side vessel 11, so that heat can be used without waste.

[0018] According to the above (7), when each of the pair of containers is large, it is not necessary to manufacture a vacuum double-walled container by welding in a reduced-pressure, nearly vacuum environment, which makes it possible to reduce manufacturing costs. There is no need to evacuate the inside of the welded vacuum double-walled container for a long time. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram showing an energy storage device according to an embodiment of the present invention; [Figure 2A] FIG. 2 is a perspective view showing one of a pair of containers of the present embodiment. [Figure 2B] FIG. 2 is a perspective cross-sectional view illustrating the inside of one of a pair of containers of the present embodiment. [Figure 2C] FIG. 2 is a perspective view showing a water pipe section and a thermal unit inside one of a pair of containers of the present embodiment. [Figure 3] FIG. 2 is a schematic diagram illustrating a thermal unit according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. An energy storage device 1 of this embodiment is a device that circulates and stores energy through chemical heat storage. The energy storage device 1 generates heat through a chemical reaction of a heat storage material 3 stored inside a pair of containers 10 consisting of two containers 10a. As shown in FIG. 1, the energy storage device 1 has the pair of containers 10, the heat storage material 3, a reaction section 2, an ejector 4, a water pipe section 5, a generator 6, a condenser 7, a tank 8, and piping 9. The energy storage device 1 also has a water vapor flow path 43, a negative pressure first flow path 41, a negative pressure second flow path 42, and a regenerated water vapor flow path 44, which are formed by the piping 9.

[0021] The heat storage material 3 is a chemical substance that separates into a heat storage product and a produced fluid when heated, and releases heat through the reverse reaction. For example, the heat storage material 3 is an alkaline earth metal that reacts with water. Specific examples include calcium oxide (CaO) and water vapor (HO), and magnesium oxide (MgO) and water vapor (HO), and in this embodiment, calcium oxide and water vapor will be used as an example.

[0022] The pair of containers 10 includes a heat generation side container 11 in which the heat storage material 3 generates heat, and a regeneration side container 12 in which the heat storage material 3 used for heat generation is regenerated. The heat generation side container 11 and the regeneration side container 12 have the same configuration, and are used by switching between heating and water supply so that their roles alternate. Water or steam is supplied to the heat generation side container 11, causing the heat storage material 3 to generate heat, and the regeneration side container 12 is heated, regenerating the heat storage material 3. The pair of containers 10 are connected by piping 9. The piping 9 is composed of pipes that form each flow path through which water, hot water, steam, etc., described below, flows.

[0023] As shown in FIGS. 2A and 2B, each of the pair of containers 10a has a double wall including an inner wall 111 and an outer wall 112. The container 10a is made of, for example, metal, and has a space inside that can accommodate a reaction unit 2, which will be described later. The inner wall 111 is disposed inside the container 10a, and the outer wall 112 is disposed outside the container 10a. A space is formed between the inner wall 111 and the outer wall 112, and the pressure inside the space is reduced to near vacuum when the energy storage device 1 is in operation.

[0024] The inner wall 111 and the outer wall 112 are joined together under atmospheric pressure during manufacturing. The inner wall 111 and the outer wall 112 are assembled and joined by known methods, such as fastening with fastening members such as screws or bolts, or by placing a sealing member between them, but are not joined by welding. A method of forming a double wall without welding, for example, is to form flanges (not shown) at the upper ends of the inner wall 111 and the outer wall 112 so that they overlap each other, and then seal the flanges of the inner wall 111 and the outer wall 112 and fasten them together with bolts. The flanges may be formed to extend circumferentially outward from the upper end of the side surface of the container 10a, or they may be formed to bend inward from the upper end of the side surface of the container 10a. Alternatively, the upper ends of the inner wall 111 and the outer wall 112 may be bent toward each other to seal the joint. Furthermore, a top lid 113 is placed on the double-walled container 10a. The top lid 113 may be fixed with bolts or the like to the overlapping portion of the flange portions of the inner wall 111 and the outer wall 112. By joining the inner wall 111 and the outer wall 112 by a method other than welding rather than by welding, when each of the pair of containers 10 is large, it is not necessary to manufacture a vacuum double-walled container by welding in a reduced-pressure, approximately vacuum environment, and this makes it possible to reduce manufacturing costs.

[0025] 2A to 2C and 3, the reaction section 2 has a plurality of thermal units 20 that cause chemical reactions. The reaction section 2 is arranged in the same configuration in the heat generation side container 11 and the regeneration side container 12. In the reaction section 2, water is supplied to calcium oxide in the heat generation side container 11 to cause an exothermic reaction, and in the regeneration side container 12, calcium hydroxide is heated to cause an endothermic reaction.

[0026] 3, the thermal units 20 are arranged so that they can be separated and replaced one by one. Each thermal unit 20 has a metal container 21, a heat storage material 3, a cover member 23, a heating member 24, and a pipe member 25.

[0027] The metal container 21 has a container body 211 and a plurality of storage chambers 212 . The container body 211 is a shallow dish-shaped container with an open top, and has a bottom surface 211a and a side wall 211b. The metal container 21 is made of a magnetic metal. Specifically, the metal container 21 is made of magnetic stainless steel. The multiple storage chambers 212 are made of a metallic honeycomb structure. Because the honeycomb structure is made of metal, it generates heat through electromagnetic induction heating. When the honeycomb structure is placed on the container body 211, the partition walls 212a are arranged so that they extend vertically from the bottom surface to the upper opening, and the multiple spaces separated by the partition walls 212a form the storage chambers 212. The height of the partition walls 212a is configured so that it does not exceed the height of the container body 211 and is lower than the upper ends of the side walls 211b of the container body 211.

[0028] The heat storage material 3 is made of calcium oxide formed into granules. The heat storage material 3 is filled and stored in the storage chamber 212 of the metal container 21. The granular material may be in any shape, including granular or powdery form, regardless of particle size.

[0029] The lid member 23 is a metal cover provided on the upper part of the metal container 21 and covering the metal container 21. The lid member 23 has through-holes 23a at the top and bottom through which steam can pass. The specific shape of the lid member 23 may be a mesh or a punched metal plate with circular holes formed in it.

[0030] The heating member 24 is a plate-shaped member provided at the bottom of the metallic container 21. The heating member 24 is an induction heater and heats the bottom surface 211a of the metallic container 21. The heating member 24 is heated by energization and its temperature increases.

[0031] The pipe member 25 is a cylindrical body made of a nonmagnetic metal and attached to the top of the cover member 23. Specifically, it is a copper pipe. The pipe member 25 is a water supply pipe with a water flow passage 250 through which water flows, and also a tube with an integrated induction coil for heating. As shown in FIG. 3, when the heating units 20 are stacked one above the other, the bottom surface 211a of the metal container 21 is located above the pipe member 25, and the cover member 23 is located below. An insulating plate 27 is provided between the pipe member 25 and the metal container 21 to prevent the pipe member 25 from directly contacting the metal container 21. The insulating plate 27 has a through-hole and is made of insulating, heat-resistant ceramics, glass, or the like. In addition to the insulating plate 27, a permeable mat (nonwoven fabric), cloth (woven fabric), or sheet made of glass fiber or ceramic fiber can also be placed on the top surface of a cover member with a through-hole to insulate the metal container 21 from the pipe member 25. The pipe member 25 includes a pipe body 251 , a dripping portion 252 , and an induction coil portion 253 .

[0032] 2A to 2C, a plurality of pipe bodies 251 are arranged adjacent to each other so as to cover the lid member 23. The longitudinal direction of the pipe bodies 251 extends along the upper or lower surface of the metal container 21.

[0033] Dripping portion 252 is a slit provided on the lid member 23 side, i.e., the lower part, of pipe body 251. When water flows inside pipe body 251, water drips from dripping portion 252 formed at the lower part and falls toward metal container 21 located below.

[0034] The induction coil section 253 is a copper wire wound in a coil shape on the surface of the pipe main body 251. The induction coil section 253 is integrated with the pipe main body 251. The pipe main body 251 and the induction coil section 253 are both heated, thereby heating the heat storage material 3.

[0035] Renewable energy such as solar power or wind power may be used as the electricity for heating the reaction section 2. By operating the energy storage device 1 while using renewable energy, it becomes possible to use the unstable supply of electricity to produce other energy and store it.

[0036] 1, the ejector 4 is provided in the piping 9. The ejector 4 sucks in high-pressure steam supplied from the heat-generating side container 11 and generates negative pressure by the Venturi effect. The ejector 4 is provided in a steam flow path 43, which will be described later.

[0037] The steam flow path 43 is a pipe 9 connected to the pair of containers 10, and is a flow path through which steam generated in the heat-generation side container 11 flows when one of the pair of containers 10 functions as the heat-generation side container 11. As shown in FIG. 1, the steam flow path 43 is provided with an ejector 4 and is connected to the generator 6 and the condenser 7. In FIGS. 2A and 2B, the steam flow path 43 is omitted. Although not shown in FIG. 1, the steam flow path 43 may extend from the right-side container 10a in FIG. 1 when the right-side container 10a functions as the heat-generation side container 11.

[0038] The negative pressure first flow path 41 is a pipe 9 that is connected from the ejector 4 to the inside of the regeneration-side container 12 via a check valve 45 arranged near the ejector 4. In the negative pressure first flow path 41, the air inside the regeneration-side container 12 is sucked in and reduced in pressure by the negative pressure generated by the Venturi effect of the ejector 4. The inside of the regeneration-side container 12 is reduced in pressure and heated, whereby calcium hydroxide (Ca(OH)2) is regenerated into calcium oxide (CaO).

[0039] The negative pressure second flow path 42 is a pipe 9 that is connected from the ejector 4 to between the inner wall 111 and the outer wall 112 of each of the pair of containers 10 via a check valve 45 that is arranged near the ejector 4. In the negative pressure second flow path 42, the air in the double walls of each container 10a is sucked in and reduced in pressure by the negative pressure generated by the Venturi effect of the ejector 4.

[0040] The regenerated steam flow path 44 is a pipe that connects the heat generation side container 11 and the regeneration side container 12. As shown in Fig. 1, the regenerated steam flow path 44 is provided with an ejector 4, which sucks in steam from inside the regeneration side container 12 using negative pressure due to the Venturi effect of the ejector 4 and supplies the sucked steam to the heat generation side container 11.

[0041] The generator 6 is disposed downstream of the steam flow path 43 and the ejector 4. The generator 6 generates electricity using the steam generated in the thermal unit 20. The type of generator 6 is not particularly limited as long as it can use steam, heat, pressure, etc. For example, it may be a steam turbine, a screw-type generator, etc. Furthermore, it may not only use steam directly, but also be a device that generates electricity using heat, such as a thermoelectric element or a Stirling engine. Furthermore, it may generate electricity using the energy generated when the steam is decompressed.

[0042] The condenser 7 is disposed downstream of the generator 6. The condenser 7 cools and condenses the steam generated in the thermal unit 20 and the steam used for power generation, and condenses it into water. In the condenser 7, impurities such as carbon dioxide contained in the steam can be removed, and the water can be supplied to the thermal unit 20 as pure water.

[0043] The tank 8 is a sealed container that stores the water condensed by the condenser 7. A heat unit water supply passage 81 that supplies water to the heat unit 20 extends from the tank 8.

[0044] The thermal unit water supply passage 81 is connected to each thermal unit 20 of the pair of containers 10. A pump 82 is arranged in the thermal unit water supply passage 81, and when one of the pair of containers 10 is used as the heat-generating container 11, water is supplied to the thermal unit 20 of the heat-generating container 11. The thermal unit water supply passage 81 communicates with the water flow passage 250 of the pipe member 25 in the thermal unit 20. By supplying the pure water returned by the condenser 7 to the thermal unit 20, unintended generation of calcium carbonate, etc. is suppressed.

[0045] As shown in FIGS. 2A to 2C, the water pipe section 5 is disposed around the thermal unit 20 inside each of the pair of containers 10, and water, hot water, steam, etc. flows inside.

[0046] The water pipe section 5 has a vertical pipe 51 , an upper annular section 52 , and a lower annular section 53 . A plurality of vertical pipes 51 are arranged so as to surround the periphery of the heat unit 20. The vertical pipes 51 are arranged so that the longitudinal direction of the substantially cylindrical pipes extends along the vertical direction, and are arranged side by side so as to form a substantially ring shape around the periphery of the heat unit 20 in a plan view. The upper annular portion 52 is an annular member that connects the upper ends of the multiple vertical pipes 51 and is hollow inside. The lower annular portion 53 is an annular member that connects the lower ends of the multiple vertical pipes 51, and is configured to be hollow inside. The upper annular portion 52, the lower annular portion 53, and the vertical pipe 51 are internally connected to each other, and liquid can move through the interiors of each.

[0047] The water pipe section 5 is connected to a water supply source such as a water supply line, and water can be supplied to the inside from the water supply line via a water supply channel 54. Furthermore, the temperature of the water pipe section 5 rises when the pair of containers 10 and the thermal unit 20 are heated, and the water inside turns into hot water or steam. The raised hot water or steam can be discharged from the water pipe section 5 via the hot water channel 55 and used. Furthermore, while the heat storage material 3 is being regenerated in the regeneration side container 12, water is not supplied to the water pipe section 5, but by providing a valve 55a or the like in the hot water channel 55 or forming a supply flow path, the hot water or steam in the water pipe section 5 can be supplied to the water pipe section 5 of the heat generation side container 11.

[0048] According to this embodiment, the following effects are achieved. (1) In the energy storage device 1 that generates heat by a chemical reaction of the heat storage material 3 stored inside the container 10a, the container 10a is configured with a double wall having an inner wall 111 and an outer wall 112. A pair of containers 10 is configured by a heat generation side container 11 in which the heat storage material 3 generates heat, and a regeneration side container 12 in which the heat storage material 3 used for heat generation is regenerated. The pair of containers 10 are connected by a pipe 9 provided with an ejector 4. Since the heat generation side container 11 and the regeneration side container 12 are connected by a pipe 9 equipped with an ejector 4, the pressure in the regeneration side container 12 can be reduced by utilizing the steam airflow generated from the heat generation side container 11. This eliminates the need for an electric vacuum pump or the like, and is inexpensive and trouble-free, making it easy to reduce the pressure in the regeneration side container 12. Furthermore, reducing the pressure in the regeneration side container 12 promotes chemical reactions in one direction, promoting oxidation and reducing the energy required to regenerate the heat storage material 3.

[0049] (2) According to this embodiment, the system is configured to include a water vapor flow path 43 through which the water vapor generated in the heat generation side container 11 flows and in which the ejector 4 is provided, and a negative pressure first flow path 41 that connects the ejector 4 to the inside of the regeneration side container 12. The negative pressure generated by the Venturi effect of the ejector 4 sucks air from the negative pressure first flow path 41 inside the regeneration side container 12, thereby reducing the pressure. Since the pressure in the regeneration side container 12 can be reduced by the negative pressure caused by the Venturi effect of the ejector 4, an electric vacuum pump or the like is not required, and since it is inexpensive and does not break down, the pressure in the regeneration side container 12 can be reduced easily.

[0050] (3) According to this embodiment, the system includes a steam flow path 43 through which the steam generated in the heat-generating side container 11 flows and in which the ejector 4 is provided, a check valve 45 disposed near the ejector 4, and a negative pressure second flow path 42 connected from the ejector 4 to between the inner wall 111 and the outer wall 112 of each of the pair of containers 10 via the check valve 45. The negative pressure generated by the Venturi effect of the ejector 4 sucks air from the double wall of the container 10a through the negative pressure second flow path 42, thereby reducing the pressure. Since the pressure between the inner wall 111 and the outer wall 112 can be reduced by the negative pressure caused by the Venturi effect of the ejector 4, an electric vacuum pump or the like is not required, and it is inexpensive and does not break down, so the regeneration side container 12 can be easily reduced in pressure. In addition, since the space between the double walls can be reduced in pressure and maintained in a substantially vacuum state, insulation is high and thermal efficiency is good. Therefore, insulation material for the pair of containers 10 is not required, recycling is easy, and environmental burden is reduced.

[0051] (4) According to this embodiment, the heat storage material 3 is made of alkaline earth metal. Water is supplied to the heat generation side container 11, causing the heat storage material 3 to generate heat, which heats the regeneration side container 12 and oxidizes the hydroxide of the alkaline earth metal, thereby regenerating the heat storage material 3. The heat generation side container 11 and the regeneration side container 12 are connected, and a regeneration steam flow path 44 is included, through which water vapor generated from the regeneration side container 12 flows and in which the ejector 4 is provided. Negative pressure generated by the Venturi effect of the ejector 4 draws water vapor from the regeneration side container 12 into the heat generation side container 11, and the water vapor is supplied to the heat generation side container 11. The water vapor generated by the endothermic reaction of the heat storage material 3 inside the regeneration-side container 12 is decompressed and sucked in by the ejector 4. Because the water vapor generated during the regeneration of the heat storage material 3 is discharged outside the regeneration-side container 12, less thermal energy is required for regeneration, and the temperature required for regeneration is also lower. This also shortens the time required for regeneration. Furthermore, because the air and water vapor inside the regeneration-side container 12 are decompressed by the ejector 4, heat loss from the heated regeneration-side container 12 is reduced.

[0052] (5) According to this embodiment, the heat storage material 3 is made of a metal oxide that reacts with water, and the pair of containers 10 are switched between the heat generation side container 11 and the regeneration side container 12 so that their roles are alternated between heating and water supply. By alternately switching between the heat generation side container 11 and the regeneration side container 12, it becomes possible to continuously regenerate and store energy.

[0053] (6) According to this embodiment, the pair of containers 10 are each provided with a water pipe section 5 through which water or hot water and steam can flow. In the regeneration side container 12, water is not supplied to the water pipe section 5 during regeneration of the heat storage material 3, but the hot water or steam in the water pipe section 5 is supplied to the water pipe section 5 of the heat generation side container 11. The water in the water pipe section 5 heated during regeneration turns into steam and is supplied to the water pipe section 5 of the heat-generating side vessel 11, thereby making it possible to utilize the heat without waste.

[0054] (7) According to this embodiment, in the method for manufacturing the energy storage device 1, the inner wall 111 and the outer wall 112 of the double walls are joined together under atmospheric pressure. When each of the pair of containers 10 is large, it is not necessary to manufacture a vacuum double-walled container by welding in a reduced-pressure, nearly vacuum environment, which reduces manufacturing costs. Also, it is not necessary to evacuate the inside of the welded vacuum double-walled container for a long time.

[0055] The present invention is not limited to the above-described embodiment, and includes modifications and improvements within the scope of achieving the object of the present invention. In the above-described embodiment, for convenience of explanation, one ejector 4 is illustrated, but there may be multiple ejectors 4, and one may be provided for each negative pressure flow path. In addition, various valves may be provided in the flow paths for air, steam, water, etc. as needed. [Explanation of symbols]

[0056] 1 Energy storage device 3. Heat storage material 4 Ejector 5 Water pipe section 9 Piping 10 Pair of containers 10a container 11 Heat generating container 12 Recycled container 41 Negative pressure first flow path 42 Negative pressure second flow path 43 Steam flow path 44 Regenerated steam flow path 45 Check valve 111 Inner wall 112 Outside wall

Claims

1. An energy storage device that generates heat through a chemical reaction of a heat storage material stored inside a container, The container is double-walled, having an inner wall and an outer wall; a heat generation side container in which the heat storage material generates heat, and a regeneration side container in which the heat storage material used for heat generation is regenerated, forming a pair of containers; the pair of containers are connected by a pipe provided with an ejector, a steam flow path through which the steam generated in the heat-generating side container flows and in which the ejector is provided; a negative pressure first flow path connected from the ejector to the inside of the regeneration side container, The energy storage device, wherein the air in the regeneration side container is sucked through the first negative pressure flow path by a negative pressure generated by a Venturi effect of the ejector, thereby reducing the pressure.

2. A check valve disposed near the ejector; a negative pressure second flow path connected from the ejector through the check valve between the inner wall and the outer wall of each of the pair of containers, 2. The energy storage device according to claim 1, wherein the air in the double wall of the container is sucked through the second negative pressure flow path by a negative pressure generated by a Venturi effect of the ejector, thereby reducing the pressure.

3. The heat storage material is an alkaline earth metal, Water is supplied to the heat generation side container, causing the heat storage material to generate heat, and the regeneration side container is heated, causing the hydroxide of the alkaline earth metal to be oxidized and regenerating the heat storage material, a regeneration steam flow path that connects the heat generation side container and the regeneration side container, through which steam generated in the regeneration side container flows, and in which the ejector is provided; 3. The energy storage device according to claim 1, wherein water vapor is sucked from the regeneration-side container to the heat-generation-side container by a negative pressure generated by a Venturi effect of the ejector, and is supplied to the heat-generation-side container.

4. The heat storage material is a metal oxide that reacts with water, 3. The energy storage device according to claim 1, wherein the pair of containers are switched between the heat generation container and the regeneration container so that the roles of the heat generation container and the regeneration container alternate.

5. a water pipe portion disposed in each of the pair of containers and through which water or hot water and steam can flow; 5. The energy storage device according to claim 4, wherein in the regeneration side container, water is not supplied to the water pipe section during regeneration of the heat storage material, and hot water or steam in the water pipe section is supplied to the water pipe section of the heat generation side container.

6. A method for manufacturing the energy storage device according to claim 1 or 2, comprising: The method for manufacturing an energy storage device, wherein the inner wall and the outer wall of the double wall are joined together under atmospheric pressure.

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