JP2010176939A - Power storage system, and operation method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power storage system capable of more efficiently utilizing thermal energy between terms of a power generation and electrolyzation, and also improving storage efficiency of electric power, and to provide an operation method thereof with little fear of breakage of a solid oxide electrolyte due to switching between the electrolyzation and the power generation. <P>SOLUTION: The power storage system is equipped with an electrolyzation-cum-power generation cell 2 provided with the solid oxide electrolyte 15 and used both as a steam electrolyzation cell and a power generation cell, a gas supplying means 3 which supplies fuel gas and air, respectively, to the electrolyzation-cum-power generation cell 2, a steam supplying means supplying steam to the electrolyzation-cum-power generation cell 2, a first and a second reheating heat exchangers which perform heat exchange between exhausted gas discharged from the electrolyzation-cum-power generation cell 2 and the fuel gas and the air supplied to the electrolyzation-cum-power generation cell 2, respectively, and a temperature control system 11 which controls inner temperature of the electrolyzation-cum-power generation cell 2 to a predetermined temperature by circulating a heating medium in the cell. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power storage system including an electrolytic and power generation unit that includes a solid oxide electrolyte and serves as both a steam electrolysis cell and a power generation cell, and an operation method thereof.

  If there is a significant difference in power consumption between daytime and nighttime, or if there are many wind power plants that have different power generation capacity depending on the wind conditions in the power system, surplus nighttime power, etc., is used for effective use of the power generation facilities. It is necessary to store electric power and discharge it during the daytime when electric power demand peaks to cope with peak load. As a representative example of a power storage device that stores surplus power, a large-scale power generation facility includes a pumped-storage power plant with good responsiveness. The pumped-storage power plant pumps up water to the dam with surplus electricity at night and generates electricity with the water pumped up to the dam during the day to cope with peak loads.

  Further, as a relatively large-scale device, there is an electric power storage device using hydrogen (for example, see Patent Document 1 and Patent Document 2). This is based on the fact that a solid oxide fuel cell can generate power by adding oxygen and hydrogen, but as an inverse reaction, it can be electrolyzed by applying voltage by adding water vapor to obtain oxygen and hydrogen. Electric power is used to electrolyze water vapor to produce hydrogen to store the electric power, and when electric power is needed, the produced hydrogen is used to generate electricity.

  Patent Document 1 discloses an electrolysis / power generation unit that includes a solid oxide electrolyte and serves as both a water vapor electrolysis cell and a fuel cell, a storage unit for hydrogen and oxygen generated by the electrolysis / power generation unit, and an electrolysis / power generation unit. It has a heat exchange means that absorbs exhaust heat, a hot water supply means for heating that uses heat obtained by the heat exchange means, and a cooling water supply means for cooling, and is a system that mainly uses the heat generated during power generation for cooling and heating. . Also, in Patent Document 2, the oxygen and hydrogen / water vapor flow paths supplied to the solid oxide fuel cell are the same during power generation and during electrolysis.

  In addition, in a power storage system equipped with a solid electrolyte cell capable of reversible operation of steam electrolysis and solid fuel cells in a power generation plant, one of the heat necessary for steam electrolysis is produced when hydrogen is produced by surplus power and stored. The main steam on the power plant side is used for the part, and at the time of power generation, the surplus heat from the solid electrolyte cell is used to superheat the main steam on the power plant side to effectively use the heat energy (for example, Patent Document 3). reference). Further, in a power storage device using a solid electrolyte, hydrogen and oxygen are subjected to an exothermic reaction, and water heated by the generated thermal energy is supplied to a reaction cell that generates electricity as water to be electrolyzed, There is one in which the electrolysis efficiency is increased (for example, see Patent Document 4).

  However, effective use of heat generated during power generation and effective acquisition of heat required during electrolysis are required, and when using heat generated during power generation, supply and use must be harmonized. There is a demand for effective use of heat. In addition, since solid oxide fuel cells have lower power storage efficiency than fuel cells using methane as a fuel, it is a problem to improve them, and the solid oxide electrolyte is a ceramic. If a sudden temperature change occurs due to switching between electrolysis and power generation, the solid oxide electrolyte may be damaged.

Japanese Patent No. 3253985 Japanese Patent No. 3105668 JP 2001-160404 A JP 2001-332271 A

  The present invention has been made in view of the above situation, and the object of the present invention is to enable more effective use of heat between power generation and electrolysis and to improve power storage efficiency. Another object of the present invention is to provide a power storage system that can reduce the risk of damage to a solid oxide electrolyte due to switching between electrolysis and power generation, and an operation method thereof.

  The present invention achieves the above object, and an electric power storage system includes an electrolysis / power generation means having a solid oxide electrolyte and serving as both a steam electrolysis cell and a power generation cell, and hydrogen and water vapor in the electrolysis / power generation means. Gas supply means for supplying fuel gas and air respectively, water vapor supply means for supplying water vapor to the electrolysis / power generation means, exhaust gas discharged from the electrolysis / power generation means, and the electrolysis / power generation means A power storage system comprising heat exchange means for exchanging heat with fuel gas and air, respectively, wherein the internal temperature of the electrolysis / power generation means is set to a predetermined temperature by circulating a heat medium inside the electrolysis / power generation means. A temperature control system for controlling is provided.

  Also, the operation method of the power storage system includes an electrolysis / power generation unit having a solid oxide electrolyte and serving as both a steam electrolysis cell and a power generation cell, and a fuel gas and air composed of hydrogen and water vapor in the electrolysis / power generation unit. Gas supply means for supplying water, steam supply means for supplying water vapor to the electrolysis / power generation means, exhaust gas discharged from the electrolysis / power generation means, the fuel gas and air supplied to the electrolysis / power generation means, A method of operating a power storage system comprising a heat exchanging means for performing heat exchange and a temperature control system for controlling the internal temperature of the electrolysis / power generation means to a predetermined temperature, wherein the electrolysis / power generation means is operated as an electrolysis cell. During the electrolysis mode operation, the temperature of the solid oxide electrolyte of the electrolysis and power generation means is operated at a lower temperature than during the power generation mode operation that operates as a power generation cell. A method characterized by and.

  According to the present invention, heat can be used more effectively between power generation and electrolysis, and power storage efficiency can be improved. By switching between electrolysis and power generation, solid oxidation of the electrolysis and power generation means can be achieved. This has the effect of reducing the possibility of damage to the physical electrolyte.

It is a lineblock diagram showing the electric power storage system concerning a 1st embodiment of the present invention. It is a perspective view which shows schematic structure of the principal part of the electrolytic power generation combined apparatus in the 1st Embodiment of this invention. It is a figure which shows schematic structure of the temperature control system in the 2nd Embodiment of this invention. It is a figure which shows schematic structure of the temperature control system in the 3rd Embodiment of this invention. It is a figure which shows schematic structure of the deformation | transformation form of the temperature control system in the 3rd Embodiment of this invention. It is a figure which shows schematic structure of the temperature control system in the 4th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a first embodiment will be described with reference to FIGS. FIG. 1 is a configuration diagram showing an electric power storage system, and FIG. 2 is a perspective view showing a schematic configuration of a main part of the apparatus for combined use with electrolytic power generation.

  1 and 2, the power storage system 1 is configured to include an electrolysis / power generation cell 2 having a solid oxide electrolyte that is an electrolysis / power generation means that serves both as a steam electrolysis cell and a power generation cell. The electrolysis / power generation cell 2 generates electric power as a solid oxide electrolyte fuel cell using the supplied hydrogen, water vapor fuel gas and air, and supplies electric power. Further, surplus electric power and water vapor are supplied, so that hydrogen is generated by water vapor electrolysis. And oxygen is generated and electricity is stored by storing these.

  The power storage system 1 includes a hydrogen storage tank 4 as gas supply means 3 for supplying hydrogen and water vapor fuel gas and air to the electrolysis / power generation cell 2, and heat exchange means on the hydrogen electrode side of the electrolysis / power generation cell 2. A first regenerative heat exchanger 5 and a condenser 6 are provided, and an air supply source 7 and a second regenerative heat exchanger 8 as a heat exchanging means are provided on the oxygen electrode side. Furthermore, the power storage system 1 is provided with a regenerator 10 as a heat storage means for storing heat generated in the electrolysis / power generation cell 2 when generating power and heating water from the water supply source 9 when storing power. It has been. Although not shown, an oxygen storage tank for storing oxygen is provided on the oxygen electrode side during steam electrolysis, and oxygen can be supplied to the electrolysis / power generation cell 2 as necessary during power generation. It is like that.

  Further, a temperature control system 11 is formed between the regenerator 10 for heating water from the water supply source 9 and the electrolysis / power generation cell 2 in order to bring the inside of the electrolysis / power generation cell 2 to a predetermined temperature. The temperature control system 11 includes a medium flow path 12 through which a heat medium such as N 2, CO 2, and He that is a sealed gaseous heat medium flows through the inside of the electrolysis / power generation cell 2 and further flows through the regenerator 10. The medium circulation loop 13 provided is formed. A circulation fan 14 is inserted into the medium flow path 12, and the heat medium circulates through the medium flow path 12 by the circulation fan 14 and circulates through the medium circulation loop 13.

  Moreover, the electrolysis / power generation cell 2 constituting the main part of the power storage system 1 has porous electrodes 16 and 17 made of, for example, platinum on both surfaces of a solid oxide electrolyte 15 made of ceramics such as stabilized zirconia. Further, a unit cell in which end plates 18 and 19 having conductivity or a separator plate 20 having conductivity are arranged on the other surface side of the porous electrodes 16 and 17 is used as a unit cell. It is configured by The current A in the electrolysis / power generation cell 2 flows in the stacking direction of the unit cells.

  Further, the end plates 18 and 19 and the separator plate 20 are provided with a fuel gas passage 21 and an air passage 22 so that fuel gas and air circulate in a direction orthogonal to each other. A plurality of flow channel pipes 23 that penetrate in the same direction to form the flow channel 12 are provided so as to form a one-through configuration. Note that one flow path pipe 23 may be arranged so as to meander around the separator plates 18, 19, and 20 to cover the whole. In this case, there are only two ends of the flow channel pipe 23, namely, an inlet and an outlet.

  In the power storage system 1 configured as described above, in the power generation mode in which power generation is performed using the electrolysis / power generation cell 2 as a power generation cell, as shown by the solid line arrow in FIG. Gas is supplied from the hydrogen storage tank 4 and the condenser 6 to the hydrogen electrode side of the electrolysis / power generation cell 2 via the first reheat exchanger 5. Further, as indicated by a one-dot chain line arrow in FIG. 1, air is supplied from the air supply source 7 to the oxygen electrode side via the second reheat exchanger 8. Reference numerals 24 and 25 are blowers inserted into the supply path so as to control the flow rates of fuel gas and air.

  The fuel gas supplied to the electrolysis / power generation cell 2 flows through the fuel gas passage 21 and the air flows through the air passage 22 to generate power. Since the power generation is an exothermic reaction, the exhaust gas of the fuel gas and air after the power generation, which is at a high temperature, flows through the first reheat exchanger 5 and the second reheat exchanger 8, respectively, Exchanges heat with fuel gas and air supplied to the pole side. Thereby, fuel gas and air are supplied to the electrolysis / power generation cell 2 in a heated state, and the heat of the exhaust gas is effectively used. The exhaust gas of the fuel gas after power generation is a mixed gas of hydrogen and water vapor. After flowing through the first reheat exchanger 5, it flows into the condenser 6, condenses in the condenser 6, and is separated into water and steam. And water and hydrogen are discharged. The separated hydrogen is supplied again as fuel gas to the electrolysis / power generation cell 2.

  On the other hand, the heat of the electrolysis / power generation cell 2 generated by the power generation heats the heat medium flowing through the medium flow path 12 of the medium circulation loop 13 constituting the temperature control system 11 by the circulation fan 14, thereby causing the electrolysis / power generation cell. 2 is taken out to heat the regenerator 10. Further, by controlling the rotation of the circulation fan 14, the flow rate of the heat medium can be controlled, and the amount of heat discharged to the outside can be adjusted. In this way, the temperature control system 11 removes the heat inside the electrolysis / power generation cell 2, the cell temperature can be maintained at an appropriate value, and overheating of the solid oxide electrolyte 15 and the like can be avoided. When the heat storage temperature of the heat accumulator 10 is set to a predetermined temperature, for example, about 800 ° C., a heating gas combustion means (not shown) is provided when only the temperature rise using the medium circulation loop 13 is insufficient. Also good.

  Further, in the electrolysis mode in which steam electrolysis is performed using the electrolysis / power generation cell 2 as a steam electrolysis cell, water is supplied from the water supply source 9 to the hydrogen electrode side of the electrolysis / power generation cell 2 as shown by a broken line arrow in FIG. 10, supplied via the first reheat exchanger 5. Further, as indicated by a one-dot chain line arrow in FIG. 1, air is supplied from the air supply source 7 to the oxygen electrode side via the second reheat exchanger 8. The flow rate of water supplied from the water supply source 9 can be controlled by the blower 26.

  The water supplied to the electrolysis / power generation cell 2 is heated while flowing through the heat accumulator 10 and the first reheat exchanger 5, and is supplied to the hydrogen electrode side as water vapor. The amount of water vapor supplied to the hydrogen electrode side can be adjusted to an appropriate value by a control valve 27 inserted between the first reheat exchanger 5 and the hydrogen electrode side of the electrolysis / power generation cell 2. . Then, the water vapor supplied to the electrolysis / power generation cell 2 flows through the fuel gas flow path 21, the air flows through the air flow path 22, and surplus power from the outside is supplied to the electrolysis / power generation cell 2 to flow current. As a result, steam electrolysis is performed, and hydrogen and oxygen are generated.

  The hydrogen generated by the steam electrolysis is discharged from the hydrogen electrode side of the electrolysis / power generation cell 2, flows through the first reheat exchanger 5, flows into the condenser 6, condenses in the condenser 6, and is separated from the water. Water and hydrogen are discharged. The separated hydrogen is stored in the hydrogen storage tank 4 so as to be compressed by a pump or the like. Oxygen generated by steam electrolysis is discharged from the oxygen electrode side of the electrolysis / power generation cell 2, flows through the second reheat exchanger 8, and is stored in an oxygen storage tank (not shown) or the like.

  In this way, the surplus power is stored, that is, stored, by electrolyzing water vapor with surplus power from the outside, generating hydrogen and oxygen, and storing them respectively. Hydrogen is stored and used as a fuel gas for power generation. However, oxygen may not be used for power generation when air is supplied to the oxygen electrode side of the electrolysis / power generation cell 2 to generate power. There is no need to provide a storage tank.

  Further, since steam electrolysis for storing electricity is an endothermic reaction, it is necessary to supply heat from the outside of the electrolysis / power generation cell 2. For this reason, the heat required for the reaction is such that the heat stored in the regenerator 10 flows into the medium flow path 12 of the medium circulation loop 13 while flowing the heat medium while adjusting the flow rate, and enters the electrolysis / power generation cell 2. Then, the internal temperature is maintained at the required temperature, and the endothermic reaction is maintained.

  At this time, the flow rate of the heat medium in the medium circulation loop 13 is adjusted, and the solid oxide electrolyte 15 of the electrolysis / power generation cell 2 is operated at a temperature lower than the temperature in the power generation mode. Thereby, the energy loss in electrical storage and electric power generation can be made small. Further, the amount of water vapor flowing in is adjusted by a control valve 27 inserted between the hydrogen electrode side of the electrolysis / power generation cell 2 and the first reheat exchanger 5, and the water vapor concentration in the electrolysis mode is changed to the water vapor concentration in the power generation mode. By operating at a higher level, energy loss in power storage and power generation can be reduced.

  As described above, according to the present embodiment, the heat generated in the electrolysis / power generation cell 2 in the power generation mode is sent to the outside by the medium circulation loop 13 so that the solid oxide electrolyte 15 and the like have a predetermined appropriate temperature. In addition, the transmitted heat is stored in the regenerator 10, and heat necessary for the endothermic reaction of water vapor electrolysis is sent from the regenerator 10 into the electrolysis / power generation cell 2 through the medium circulation loop 13 in the electrolysis mode in which electricity is stored. Steam electrolysis is maintained and also used for the generation of water vapor, so that heat can be used effectively so as to achieve harmony between the power generation mode and the electrolysis mode. In addition, since energy loss during power storage and power generation can be reduced, the efficiency of power storage can be improved. Furthermore, the solid oxide electrolyte 15 is set to a predetermined appropriate temperature, and a rapid temperature change associated with switching between the power generation mode and the electrolysis mode can be prevented, and the possibility of breakage can be reduced.

  Next, a second embodiment will be described with reference to FIG. FIG. 3 is a diagram showing a schematic configuration of the temperature control system. Note that this embodiment is different from the first embodiment only in the temperature control system, and therefore, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. A different configuration of the present embodiment will be described.

  In FIG. 3, the power storage system of the present embodiment, which is different from the configuration of the first embodiment only in the temperature control system, has its electrolysis / power generation cell 2 operating as a power generation cell by supplying fuel gas and air. The surplus power is stored by supplying the surplus power and water vapor and supplying the surplus power and water vapor to operate as a water vapor electrolysis cell and storing the generated hydrogen. The power storage system is provided with a temperature control system 30 for causing the internal temperature of the electrolysis / power generation cell 2 to be a predetermined temperature.

  The temperature control system 30 is provided outside the electrolysis / power generation cell 2, and stores the heat generated during power generation and heats the water supplied when the power is stored to generate water vapor to generate the water vapor 10. The medium distribution loop 31 is formed between the electrolysis and power generation cell 2. The medium circulation loop 31 includes a medium flow path 12 that circulates through the medium circulation loop 31 so that the enclosed heat medium flows through the inside of the electrolysis / power generation cell 2 and flows through the heat accumulator 10.

  The heat accumulator 10 is installed on the mounting portion 33 of the lifting device 32 that is a position moving means. The mounting portion 33 can be moved up and down in the vertical direction as indicated by a double arrow Y in FIG. And the heat accumulator 10 is located above the installation position of the electrolysis / power generation cell 2 by raising the placement part 33 to be positioned at the upper position point, and lowering the placement part 33. By being positioned at the lower position point, it is positioned lower than the installation position of the electrolysis / power generation cell 2.

  For this reason, in the power generation mode, the heat accumulator 10 is positioned above the electrolysis / power generation cell 2 by raising the mounting portion 33 of the lifting device 32 and positioning it at the upper position point. As a result, the internal temperature of the electrolysis / power generation cell 2 performing power generation becomes a high temperature, the heat medium sealed so as to circulate through the medium circulation loop 31 is also heated, and the heat storage device 10 is at a low temperature. Then, natural convection occurs, and the heat medium having a high temperature flows so as to rise in the medium flow path 12 and conveys heat to the heat accumulator 10 having a lower temperature. Thereby, the temperature of the regenerator 10 rises, and the heat of the electrolysis / power generation cell 2 accompanying power generation is stored in the regenerator 10.

  On the other hand, in the electrolysis mode, the heat accumulator 10 is positioned below the electrolysis / power generation cell 2 by lowering the placement portion 33 of the elevating device 32 and positioning it at the lower position point. Thereby, the internal temperature of the electrolysis / power generation cell 2 performing steam electrolysis becomes a low temperature, and the heat medium enclosed in the medium circulation loop 31 becomes a low temperature in the electrolysis / power generation cell 2, and conversely, the heat accumulator. 10 is heated to a high temperature and flows so as to circulate through the medium flow path 12 by causing natural convection, and transports the heat of the regenerator 10 to the electrolysis / power generation cell 2 having a lower temperature. With this heat transport, the temperature of the electrolysis / power generation cell 2 rises, and further heat transport continues, so that steam electrolysis, which is an endothermic reaction, proceeds, hydrogen is generated, and excess power is stored.

  By configuring as described above, the operation of the power storage system in the power generation mode and the electrolysis mode is performed in the same manner as in the first embodiment, except that the operation of the temperature control system 30 is different. Therefore, the same effects as those of the first embodiment can be obtained, the circulation of the heat medium in the temperature control system 30 does not require a circulation fan that can be used at a high temperature, an increase in cost can be avoided, maintenance, etc. Becomes easy.

  Note that a circulation assisting fan that assists circulation based on natural convection of the heat medium, for example, driven by a water-cooled driving unit, may be provided in the medium flow path 12 of the medium circulation loop 31.

  Next, a third embodiment will be described with reference to FIGS. FIG. 4 is a diagram showing a schematic configuration of the temperature control system, and FIG. 5 is a diagram showing a schematic configuration of the temperature control system in a modified embodiment. Note that this embodiment is different from each of the above embodiments only in the temperature control system. Therefore, the same parts as those of the embodiments are denoted by the same reference numerals, and the description thereof is omitted. The configuration of will be described.

  In FIG. 4, the power storage system of the present embodiment, which differs from the configuration of the first embodiment only in the temperature control system, is such that the electrolysis / power generation cell 2 supplies fuel gas and air and operates as a power generation cell. The surplus power is stored by supplying the surplus power and water vapor and supplying the surplus power and water vapor to operate as a water vapor electrolysis cell and storing the generated hydrogen. The power storage system is provided with a temperature control system 35 for ensuring that the internal temperature of the electrolysis / power generation cell 2 is an appropriate predetermined temperature.

  The temperature control system 35 is configured such that a medium circulation loop 37 is formed between the electrolysis / power generation cell 2 and the heat storage 10 that is heat storage means outside the electrolysis / power generation cell 2 and the radiator 36 that is cooling means. ing. The medium circulation loop 37 includes a medium flow path 38 in which the enclosed heat medium flows through the inside of the electrolysis / power generation cell 2 and is divided into the heat accumulator 10 and the heat radiator 36, and flows through each of them and circulates. It has become.

  For this reason, the heat medium divided into the radiator 36 flows through the medium dividing flow path 38 a so that the flow rate is adjusted to a predetermined flow rate by the inserted flow control valve 39, and is cooled while flowing through the heat radiator 36. After that, it returns to the electrolysis / power generation cell 2. On the other hand, the heat medium branched to the regenerator 10 side flows through the medium distribution flow path 38b, stores heat in the heat accumulator 10, or flows through while being heated, and then returns to the electrolysis / power generation cell 2. The flow rate control valve 39 is inserted into the medium branch flow path 38a and the flow rate is adjusted to change the flow rate ratio of the heat medium flowing through the regenerator 10 and the radiator 36, and the temperature of the heat medium returning to the electrolysis / power generation cell 2 is changed. It can be set to a desired temperature, and the internal temperature of the electrolysis / power generation cell 2 can be set to an appropriate predetermined temperature, and this temperature can be maintained.

  That is, in the power generation mode, for example, it is cooled to about 700 ° C. by the high-temperature heat medium after flowing out from the electrolysis / power generation cell 2 at about 800 ° C. and storing heat in the heat accumulator 10 and the radiator 36 by the atmosphere. A low-temperature heat medium adjusted to a predetermined flow rate is obtained, and the high-temperature heat medium and the low-temperature heat medium are mixed, whereby the heat medium flowing back to the electrolysis / power generation cell 2 flows into a desired temperature. Can be. In the electrolysis mode, the flow rate is adjusted so as to convey a high-temperature heat medium so that the electrolysis / power generation cell 2 has a necessary temperature. The heat medium is circulated through the medium circulation loop 37 by a circulation fan, a lifting device, or the like shown in the above-described embodiment (not shown).

  And the electric power storage system of this embodiment which has the temperature control system 35 of the above structure changes the internal temperature of the electrolysis / power generation cell 2 by changing the flow rate ratio of the heat medium flowing through the regenerator 10 and the radiator 36. While maintaining an appropriate predetermined temperature, in the power generation mode, while supplying power, the heat medium is heated inside the electrolysis / power generation cell 2 that is at a high temperature by power generation, and the heat accumulator 10 is stored. In the electrolysis mode, the heat medium is heated by the heat stored in the regenerator 10, transports the heat to the electrolysis / power generation cell 2, and sets the inside of the electrolysis / power generation cell 2 to an appropriate predetermined temperature, thereby performing an endothermic reaction. Steam electrolysis proceeds, hydrogen is generated, and surplus power is stored. As in the above embodiment, the steam used for steam electrolysis is obtained by heating water with the heat of the heat accumulator 10.

  With the configuration described above, the operation of the power storage system in the power generation mode and the electrolysis mode is performed in the same manner as in the first embodiment, except that the operation of the temperature control system 35 is different. Therefore, the same effect as that of the first embodiment can be obtained, and the temperature control system 35 can set the internal temperature of the electrolysis / power generation cell 2 to a more appropriate predetermined temperature and can maintain this. In addition, since the rapid temperature change is not applied to the solid oxide electrolyte membrane, the possibility of breakage can be reduced, and the possibility of failure or the like in the electrolysis / power generation cell 2 can be reduced.

  In the above embodiment, the flow rate control valve 39 is provided to adjust the flow rate of the heat medium to change the flow rate ratio of the heat medium flowing through the heat accumulator 10 and the radiator 36, and thereby the inside of the electrolysis / power generation cell 2. Although the temperature is set to an appropriate temperature, it may be configured as a modification shown in FIG. 5 to change the flow rate ratio of the heat medium.

  That is, in FIG. 5, the temperature control system 40 is configured to form a medium circulation loop 41 between the electrolysis / power generation cell 2, the heat accumulator 10, and the radiator 36. The medium circulation loop 41 includes a medium flow path 42 through which the heat medium flows through the inside of the electrolysis / power generation cell 2 and circulates through the heat accumulator 10 and the radiator 36. Further, in the medium flow path 42, the heat medium flowing out from the electrolysis / power generation cell 2 is diverted by the flow dividing section 43, flows through the medium diversion flow paths 42a and 42b, and flows to the heat accumulator 10 and the radiator 36, respectively. .

  Furthermore, a valve plate 45 that rotates as indicated by a double-headed arrow R about the rotation shaft 44 is provided in the flow dividing portion 43 of the medium flow path 42. Then, the valve plate 45 is rotated to adjust the flow rate of the heat medium flowing through the medium flow channel 42 to the medium distribution channels 42a and 42b. By adjusting the flow rate, the regenerator 10 and the radiator 36 are adjusted. The flow rate ratio of the heat medium flowing through the electrolysis / power generation cell 2 can be changed, and the temperature of the heat medium returning to the electrolysis / power generation cell 2 can be set to a desired temperature, and the internal temperature of the electrolysis / power generation cell 2 is set to an appropriate predetermined temperature. Can be maintained.

  As a result, the same effects as those of the above embodiment can be obtained in this modified embodiment.

  Next, a fourth embodiment will be described with reference to FIG. FIG. 6 is a diagram showing a schematic configuration of the temperature control system. Since the present embodiment is different from the above embodiments only in the temperature control system, the same parts as those of the embodiments are denoted by the same reference numerals and the description thereof is omitted, and the present embodiment is different from the embodiments. The configuration will be described.

  In FIG. 6, the power storage system of the present embodiment, which is different only in the configuration of the temperature control system from the configuration of the first embodiment, has its electrolysis / power generation cell 2 operating as a power generation cell by supplying fuel gas and air. The surplus power is stored by supplying the surplus power and water vapor and supplying the surplus power and water vapor to operate as a water vapor electrolysis cell and storing the generated hydrogen. The electric power storage system is provided with a temperature control system 47 for ensuring that the internal temperature of the electrolysis / power generation cell 2 is an appropriate predetermined temperature.

  The temperature control system 47 is configured to form a medium circulation loop 48 between the electrolysis / power generation cell 2, the heat storage device 10 that is a heat storage unit outside the electrolysis / power generation cell 2, and the radiator 36 that is a cooling unit. ing. The medium circulation loop 48 includes a medium flow path 38 through which the encapsulated heat medium flows through the inside of the electrolysis / power generation cell 2 and is divided into the heat accumulator 10 and the radiator 36, and flows through each of them. It has become.

  The medium flow path 38 includes a medium distribution path 38a through which the heat medium flows through the radiator 36 and a medium distribution path 38b through which the heat storage apparatus 10 flows, and the electrolysis / power generation cell 2, the radiator 36, the heat storage, and the like. Flow rate control valves 49a and 49b are inserted in the respective medium distribution channels 38a and 38b between the container 10 and the container 10. Each flow rate control valve 49a, 49b inserted in each medium branch channel 38a, 38b is configured such that its opening degree Op is adjusted under the control of the control unit 50, which is a control means. As a result, the flow rate ratio of the heat medium flowing through the regenerator 10 and the radiator 36 can be changed, and the total flow rate of the heat medium can also be changed by adjusting the flow rate at both flow rate control valves 49a and 49b. The temperature of the heat medium flowing out from the electrolysis / power generation cell 2 can also be changed.

  Regarding the control by the control unit 50 of each of the flow control valves 49a and 49b, the generated heat density of the electrolysis / power generation cell 2 in the power generation mode differs depending on the current density Id of the connected load, and is generally the current density of the load. It is based on the fact that the generated heat density of Id and the electrolysis / power generation cell 2 can be considered to be proportional. If the temperature of the heat medium is adjusted so as to cancel the change in the generated heat density, the internal temperature of the electrolysis / power generation cell 2 and the temperature of the solid oxide electrolyte membrane can be set to appropriate temperatures within an allowable range. Is shown.

  For this reason, the control by the control unit 50 is to provide a thermometer (not shown) or measure the temperature of the heat medium together with the feedforward control based on the change in the load current density Id, that is, the load fluctuation. Thus, the temperature of the solid oxide electrolyte membrane is measured, and feedback control is performed based on the change, so that highly accurate control can be performed. Each graph shown in FIG. 6 is a control graph in which the horizontal axis indicates the current density Id and the vertical axis indicates the opening degree Op of each flow control valve 49a, 49b.

  In the power generation mode, the heat medium diverted toward the radiator 36 flows through the medium diverting flow path 38 a so that the flow rate is adjusted to a predetermined flow rate by the inserted flow rate control valve 49 a and flows through the heat dissipator 36. After being cooled, the electrolysis / power generation cell 2 is returned to. On the other hand, the heat medium divided to the regenerator 10 side also flows through the medium diversion channel 38b so that the flow rate is adjusted to a predetermined flow rate by the inserted flow control valve 49b, and heat storage in the regenerator 10 is performed. And then return to the electrolysis / power generation cell 2. Further, in the electrolysis mode, the flow rate of the heat medium on the heat accumulator 10 side is increased by adjusting the flow rate of the heat medium on the radiator 36 side to be reduced by the flow rate control valve 49 a, and the heat accumulated in the heat accumulator 10 is increased. Since the heated heat medium is carried to the electrolysis / power generation cell 2, a temperature necessary for steam electrolysis can be secured.

  As described above, in the power storage system of the present embodiment having the temperature control system 47 having the above-described configuration, the flow rate of the heat medium flowing through the regenerator 10 and the radiator 36 by adjusting the flow rate by the flow rate control valves 49a and 49b. The ratio is changed and the internal temperature of the electrolysis / power generation cell 2 is maintained at an appropriate predetermined temperature, and in the power generation mode, the power is supplied and the heat medium is heated inside the electrolysis / power generation cell 2 at a high temperature by power generation. Is heated to store heat in the heat accumulator 10.

  In the electrolysis mode, water vapor used for water vapor electrolysis is obtained by heating water with the heat of the regenerator 10, and the heat medium is further heated by the heat stored in the regenerator 10 to supply heat to the electrolysis / power generation cell 2. When the inside of the electrolysis / power generation cell 2 is set to an appropriate predetermined temperature, steam electrolysis of the endothermic reaction proceeds, hydrogen is generated, and surplus power is stored. In both cases of the power generation mode and the electrolysis mode, the temperature of the heat medium that returns to the electrolysis / power generation cell 2 can be set to a desired temperature, and the internal temperature of the electrolysis / power generation cell 2 is set to an appropriate predetermined temperature. And maintaining the solid oxide electrolyte membrane at an appropriate temperature.

  As described above, with the above configuration, the operation of the power storage system in the power generation mode and the electrolysis mode is performed in the same manner as in the first embodiment, except that the operation of the temperature control system 47 is different. Therefore, the same effect as that of the first embodiment can be obtained, and the temperature control system 47 can set the internal temperature of the electrolysis / power generation cell 2 to a more appropriate predetermined temperature, and can maintain this. In addition, since the rapid temperature change is not applied to the solid oxide electrolyte membrane, the possibility of breakage can be reduced, and the possibility of failure or the like in the electrolysis / power generation cell 2 can be reduced.

DESCRIPTION OF SYMBOLS 1 ... Electric power storage system 2 ... Electrolysis and power generation cell 3 ... Gas supply means 4 ... Hydrogen storage tank 7 ... Air supply source 9 ... Water supply source 10 ... Heat storage 11 ... Temperature control system 13 ... Medium distribution loop 15 ... Solid oxide Electrolytes

Claims (8)

An electrolysis / power generation means having a solid oxide electrolyte and serving as both a water vapor electrolysis cell and a power generation cell; a gas supply means for supplying fuel gas and air each comprising hydrogen and water vapor to the electrolysis / power generation means; and the electrolysis A steam supply means for supplying steam to the power generation means; and a heat exchange means for exchanging heat between the exhaust gas discharged from the electrolysis / power generation means and the fuel gas and air supplied to the electrolysis / power generation means. A power storage system,
A power storage system comprising a temperature control system for controlling the internal temperature of the electrolysis / power generation means to a predetermined temperature by circulating a heat medium in the electrolysis / power generation means.   The temperature control system comprises a heat storage means arranged outside the electrolysis / power generation means, and a medium circulation loop for circulating the heat medium between the inside of the electrolysis / power generation means and the heat storage means. The power storage system according to claim 1.   The power storage system according to claim 2, wherein the medium circulation loop includes a circulation fan that circulates the heat medium.   During the power generation mode operation in which the temperature control system operates the electrolysis / power generation means as a power generation cell, the heat storage means is positioned above the electrolysis / power generation means, and the electrolysis / power generation means is operated as an electrolysis cell. The power storage system according to claim 2, further comprising a position moving means for positioning the heat storage means at a position below the electrolysis / power generation means during the electrolysis mode operation.   The temperature control system is connected to the electrolysis / power generation means in parallel with the heat storage means, and dissipates heat of at least a part of the heat medium flowing through the medium circulation loop to The power storage system according to claim 2, further comprising cooling means for controlling the temperature.   It comprises control means for detecting a temperature change of the solid oxide electrolyte corresponding to electrolysis of the electrolysis / power generation means and load fluctuation during power generation, and controlling the solid oxide electrolyte to a temperature within an allowable range. The power storage system according to claim 1, wherein the power storage system is a power storage system. An electrolysis / power generation means having a solid oxide electrolyte and serving as both a water vapor electrolysis cell and a power generation cell; a gas supply means for supplying fuel gas and air each comprising hydrogen and water vapor to the electrolysis / power generation means; and the electrolysis Steam supply means for supplying steam to the power generation means, heat exchange means for exchanging heat with the exhaust gas discharged from the electrolysis / power generation means, and the fuel gas and air supplied to the electrolysis / power generation means, A method of operating a power storage system comprising a temperature control system for controlling the internal temperature of the electrolysis and power generation means to a predetermined temperature,
During electrolysis mode operation in which the electrolysis / power generation means is operated as an electrolysis cell, the temperature of the solid oxide electrolyte of the electrolysis / power generation means is set to be lower than that during power generation mode operation as a power generation cell. A method for operating a power storage system characterized by the above.   The amount of water supplied to the water vapor supply means is increased during the electrolysis mode operation than in the power generation mode operation, and the water vapor concentration on the hydrogen electrode side of the electrolysis / power generation means is operated as a high concentration. Item 8. A method for operating the power storage system according to Item 7.

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