JP5101444B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device that combines a water electrolysis device and a fuel cell.

  A power storage device in which a water electrolysis device and a fuel cell are combined is connected to a natural energy power generation device such as a solar cell or a windmill that has a large temporal variation. When the power generation device is generating surplus power with respect to power demand, the power storage device operates the water electrolysis device to decompose water to generate hydrogen and oxygen, which are stored in the hydrogen tank and oxygen tank, respectively. . When the electric power demand exceeds the amount of power generation, the fuel cell is operated to generate electric power when generating water from the stored hydrogen and oxygen. As described above, leveling of the electric power generated by natural energy can be achieved by connecting the natural energy power generation device to the power storage device.

  In recent years, the gap between daytime power demand and late-night power demand has increased. When the power storage device is connected to a normal power system, it can also be used as a power leveling device using surplus power at night.

  In the above power storage device, the water electrolysis device and the fuel cell are repeatedly started and stopped. Each time the water electrolysis device or fuel cell stops, the temperature of the water electrolysis device or fuel cell decreases. Therefore, when starting the water electrolysis apparatus or the fuel cell, it is necessary to perform water electrolysis or power generation after heating the circulating water with a heater or a burner, and it takes a long time to start. As a result, there is a problem that the system efficiency is lowered.

As a means for solving the above problem, Patent Document 1 discloses a power generation system that heats and keeps a water circulation system, particularly a pure water tank, using exhaust heat from a fuel cell. According to the power generation system, by effectively utilizing the residual heat to heat the electrolyzed water, the startup time can be shortened and the efficiency during water electrolysis can be improved.
JP 2002-056880 A

  However, in the power generation system of Patent Document 1, the temperature of the electrolyzed water to be heated and kept is about 60 ° C. In order to improve the electrolysis efficiency, it is necessary to make the water for electrolysis about 60 to 120 ° C. Therefore, in the power generation system of Patent Document 1, it is necessary to further heat the water for electrolysis using a heating device such as a heater.

  The present invention has been made in view of the above problems, and provides a power storage device that can improve the efficiency by simplifying the device configuration and shortening the startup time of the water electrolysis device and the fuel cell. .

  In order to solve the above problems, the present invention accommodates a water electrolysis device that electrolyzes circulating water to generate hydrogen and oxygen, a fuel cell that generates circulating water from hydrogen and oxygen, and the circulating water. A container, a purification layer provided in the container, for purifying circulating water, a partition plate that hangs down from the top of the container body and separates the container body into a first chamber and a second chamber; A hydrogen storage section provided outside the container and comprising a hydrogen tank and a hydrogen pipe connecting the first chamber and the hydrogen tank; an oxygen tank provided outside the container; and the second tank An oxygen storage unit comprising an oxygen pipe connecting the chamber and the oxygen tank, and the circulating water discharged from the container is passed through the fuel cell and the water electrolysis device and sent to the first chamber. And a first feed that delivers hydrogen to the first chamber. A circulating water discharged from the pipe and the container passes through the fuel cell and the water electrolysis device, and is supplied to the second chamber, and oxygen is supplied to the second chamber. A feed pipe, one end of which is connected to the first feed pipe on the downstream side of the fuel cell, and a hydrogen feed pipe for supplying hydrogen to the fuel cell from the first chamber, The power storage device includes an oxygen supply pipe that is connected to the second supply pipe on the downstream side of the fuel cell and supplies oxygen to the fuel cell from the second chamber.

  Since the power storage device of the present invention has a configuration in which the fuel cell and the water electrolysis device are connected in series by the first feeding pipe and the second feeding pipe, one of the fuel cell and the water electrolysis device is During operation, even if the other of the fuel cell and the water electrolysis device is stopped, the temperature is maintained by the circulating water. Therefore, when switching between water electrolysis and power generation, an activation device for activating the stopped fuel cell or water electrolysis device is not required, and the activation time can be greatly shortened. Since the hydrogen supply pipe and the oxygen supply pipe are respectively connected to the first supply pipe and the second supply pipe on the downstream side of the fuel cell, not only when the water electrolysis apparatus is operated but also when the fuel cell is operated. The natural circulation of water in the system can be generated. Moreover, it can be set as the structure which purifies the impurity which generate | occur | produced in the water electrolysis apparatus at the time of water electrolysis, and the impurity which generate | occur | produced in the fuel cell at the time of power generation with a common purification layer. Therefore, the apparatus configuration can be simplified and the operating efficiency can be greatly improved.

  In the said invention, it is preferable that at least one of the said hydrogen piping and the said oxygen piping is arrange | positioned so that hydrogen or oxygen may be supplied in the circulating water accommodated in the said container.

  By setting it as the said structure, the electrolytic membrane used for a water electrolysis apparatus and a fuel cell can be humidified.

  According to the above invention, when switching between water electrolysis and power generation, the startup device for starting the stopped fuel cell or water electrolysis apparatus is not required, and the startup time can be greatly shortened. In addition, it is possible to generate a natural circulation of water in the system during the operation of either the water electrolysis apparatus or the fuel cell. In the power storage device of the present invention, since the purification layer of the water electrolysis device and the purification layer of the fuel cell can be used in common, the device configuration can be simplified and the operation efficiency can be greatly improved. it can.

Below, the electric power storage apparatus which concerns on this invention is demonstrated with reference to drawings.
FIG. 1 is a schematic diagram of an embodiment of a power storage device according to the present invention. The power storage device 10 according to this embodiment includes a water electrolysis device 11 that electrolyzes circulating water to generate hydrogen and oxygen, a fuel cell 12 that generates circulating water from hydrogen and oxygen, and generates electricity. And a container 13 for storing circulating water. The water electrolysis device 11 is, for example, a solid polymer membrane water electrolysis device. The fuel cell 12 is, for example, a solid polymer fuel cell.

  The container 13 is provided at a predetermined interval from the lower end surface of the container 13, purifies the circulating water, and hangs down from the top of the container 13. A partition plate 15 is provided for separation into the room 17. A heat insulating material (not shown) is disposed on the outer periphery of the container 13 so that the container 13 can be kept warm.

  Circulating water is accommodated in the container. The pressure in each room is measured by a pressure gauge (not shown) so that the water level of the circulating water in the container is constant, and the pressure in each room is adjusted to be equal. Since circulating water is consumed by water electrolysis, a water level meter (not shown) is installed in the container, and a predetermined amount of water is supplied through a water supply pipe (not shown) by a ball tap or the like.

  The purification layer 14 is made of, for example, an ion exchange resin. In order to fill the container with the ion exchange resin, a support member having a net or pores at a predetermined distance from the lower end surface of the container 13 is provided, and this support member is filled with the ion exchange resin. When the circulating water passes through the ion exchange resin of the purification layer 14, impurities in the circulating water are removed. Circulating water from which impurities have been removed by the purification layer 14 is stored below the purification layer 14 in the container 13.

  A hydrogen storage unit 20 and an oxygen storage unit 30 are provided outside the container 13. The hydrogen storage unit 20 includes a hydrogen tank 21, a hydrogen pipe 22 a that connects the top of the first chamber 16 and the hydrogen tank 21, and a hydrogen pipe that connects the hydrogen tank 21 and the side surface of the first chamber 16. 22b. The oxygen storage unit 30 includes an oxygen tank 31, an oxygen pipe 32 a that connects the top of the second chamber 17 and the oxygen tank 31, and an oxygen pipe that connects the oxygen tank 31 and the side surface of the second chamber 17. 32b.

  A first feed pipe 25 that supplies the circulating water purified by the purification layer 14 from the lower part of the container 13 to the circulating water above the first chamber 16 through the fuel cell 12 and the water electrolysis device 11. Is provided. Further, from the lower part of the container 13, the second feed that supplies the circulating water purified by the purification layer 14 to the circulating water above the second chamber 17 through the fuel cell 12 and the water electrolysis device 11. A tube 35 is provided. That is, the fuel cell 12 and the water electrolysis device 11 are connected in series by the first supply pipe 25 and the second supply pipe 35.

  A hydrogen supply pipe 26 that supplies hydrogen stored in the space above the first chamber 16 to the fuel cell 12 is provided. An oxygen supply pipe 36 for supplying oxygen stored in the space above the second chamber 17 to the fuel cell is provided. In the present embodiment, the downstream (fuel cell side) end of the hydrogen supply pipe 26 is connected to the first supply pipe 25. The downstream end of the oxygen supply pipe 36 is connected to the second supply pipe 35.

A process of leveling power using the power storage device of the present embodiment will be described below.
When nighttime power is used, or when the natural energy power generation device generates excessive power with respect to power demand, the power storage device of the present embodiment is operated in the following process.

The water electrolyzer is rated at about 80 ° C.
Circulating water is supplied from the first supply pipe 25 to the water electrolysis apparatus 11 through the fuel cell 12. Night power or surplus power is input to the water electrolysis apparatus 11. Thereby, in the water electrolysis apparatus 11, circulating water is electrolyzed and hydrogen and oxygen are generated. Circulating water is heated by internal losses that occur during electrolysis. The generated hydrogen is supplied to the circulating water above the first chamber 16 through the first supply pipe 25 together with the excess circulating water. Oxygen is supplied to the circulating water above the second chamber 17 through the second feed pipe 35 together with the excess circulating water. Therefore, the density of the mixture of circulating water and hydrogen or oxygen flowing through the first feeding pipe 25 or the second feeding pipe 35 on the downstream side of the water electrolysis device 11 is the first density on the upstream side of the water electrolysis device 11. The density becomes lower than the density of circulating water flowing through one feeding pipe 25 or the second feeding pipe 35, and natural circulation occurs in the water in the system.

  The hydrogen supplied to the first chamber 16 is discharged from the top of the first chamber 16 and supplied to the hydrogen tank 21 through the hydrogen pipe 22a. The hydrogen supplied to the hydrogen tank 21 is pressurized and stored in the hydrogen tank 21.

  The oxygen supplied to the second chamber 17 is discharged from the top of the second chamber 17, supplied to the oxygen tank 31 through the oxygen pipe 32 a, pressurized, and stored in the oxygen tank 31.

  When the circulating water in the first chamber 16 and the second chamber 17 passes through the purification layer 14 and moves to the lower part of the container 13, impurities are removed by the purification layer 14. The circulating water from which impurities have been removed passes through the fuel cell 12 from the first supply pipe 25 and the second supply pipe 35 and is supplied again to the water electrolysis apparatus 11.

  Thus, since the circulating water naturally circulates in the water electrolysis process, a pump for circulating the circulating water becomes unnecessary. Since the circulating water is heated by the internal loss generated during electrolysis, no heating means such as a heater is required, and thermal independence can be achieved. Further, since the fuel cell and the water electrolysis device are connected in series by the first feeding pipe and the second feeding pipe, the heated circulating water passes through the fuel cell and is subjected to water electrolysis (that is, The fuel cell is kept warm even when the fuel cell is stopped.

  When the power demand exceeds the power generation amount in the daytime, or when the power generation amount of the natural energy power generation device is less than the power demand, the power storage device of this embodiment is operated in the following process.

  As described above, the fuel cell 12 is kept at about 80 ° C. by the circulating water even when it is stopped (water electrolysis). Therefore, a starting device such as a heater is unnecessary, and the starting time is greatly shortened.

  The hydrogen in the hydrogen tank 21 is supplied to the circulating water in the first chamber 16 from the side surface of the first chamber 16 through the hydrogen pipe 22b. The hydrogen supplied to the first chamber 16 is supplied to the fuel cell 12 from the upper space of the first chamber 16 through the hydrogen supply pipe 26.

  Simultaneously with hydrogen, oxygen in the oxygen tank 31 is supplied to the circulating water in the second chamber 17 from the side surface of the second chamber 17 through the oxygen pipe 32b. Oxygen supplied to the second chamber 17 is supplied from the upper space of the second chamber 17 to the fuel cell 12 through the oxygen supply pipe 36.

  In the fuel cell 12, hydrogen and oxygen react to generate water and generate electricity. The generated water is heated by Joule heat generated by the reaction between hydrogen and oxygen. The heated water passes through the water electrolysis apparatus 11 through the first feed pipe 25 and the second feed pipe 35 as circulating water, and enters the first chamber 16 and the second chamber 17. Supplied. The circulating water supplied to the first chamber 16 and the second chamber 17 passes through the purification layer 14, is discharged from the lower portion of the container 13, and is discharged by the first supply pipe 25 and the second supply pipe 35. , And supplied to the fuel cell 12.

  Here, surplus hydrogen and oxygen supplied to the fuel cell 12 from the hydrogen supply pipe 26 and the oxygen supply pipe 36 and passed through the fuel cell 12 without reacting with each other on the downstream side of the fuel cell 12 respectively. Supplied to the supply pipe and the second supply pipe. Therefore, the density of the mixture of circulating water and hydrogen or oxygen flowing through the first feed pipe 25 or the second feed pipe 35 on the downstream side of the fuel cell 12 is the same as that of the first feed pipe on the upstream side of the fuel cell 12. The density becomes lower than the density of the circulating water flowing through the supply pipe 25 or the second supply pipe 35, and natural circulation occurs in the water in the system.

As described above, the power storage device of the present embodiment does not require a heating unit for starting the fuel cell, and can significantly reduce the start-up time. Since the circulating water is heated by Joule heat generated during power generation, thermal independence can be achieved. In addition, since the water electrolysis device can be kept warm during power generation, the start time of the water electrolysis device can be greatly shortened when switching to the water electrolysis process, and heating means such as a heater for starting the water electrolysis device are provided. It becomes unnecessary.
In the power storage device of the present embodiment, since the circulating water naturally circulates even during power generation, a pump for circulating the circulating water becomes unnecessary. Furthermore, since the impurities generated in the water electrolysis apparatus during water electrolysis and the impurities generated in the fuel cell during power generation can be purified by a common purification layer, the apparatus can be simplified.

  When a solid polymer membrane water electrolysis device is applied to the power storage device of this embodiment, the circulating water passes through the water electrolysis device even during power generation (when the water electrolysis device is stopped), so that the solid polymer electrolyte membrane is humidified. be able to.

  As described above, the power storage device of the present embodiment can simplify the device configuration, and greatly reduce the startup time of the water electrolysis device and the fuel cell when the operation is switched between water electrolysis and power generation. Therefore, the driving efficiency can be greatly improved. Further, it is advantageous in that the apparatus configuration can be simplified, for example, no circulating water heating means such as a heater is required.

  In the above embodiment, the heat insulating material is arranged on the outer periphery of the container. However, when the heat generation during water splitting or power generation is excessive and the circulating water temperature rises excessively, for example, the first supply pipe In addition, a heat radiating means such as a radiator can be provided in the second feed pipe.

It is the schematic of one Embodiment of the electric power storage apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electric power storage apparatus 11 Water electrolysis apparatus 12 Fuel cell 13 Container 14 Purification layer 15 Partition plate 16 1st chamber 17 2nd chamber 20 Hydrogen storage part 21 Hydrogen tank 22a, 22b Hydrogen piping 25 1st feed pipe 26 Hydrogen Supply pipe 30 Oxygen storage section 31 Oxygen tanks 32a, 32b Oxygen pipe 35 Second supply pipe 36 Oxygen supply pipe

Claims (2)

A water electrolyzer that electrolyzes the circulating water to produce hydrogen and oxygen;
A fuel cell that generates circulating water from hydrogen and oxygen;
A container for containing circulating water;
A purification layer provided in the container for purifying circulating water;
A partition plate that hangs down from the top of the container body and separates the inside of the container body into a first chamber and a second chamber;
A hydrogen storage unit provided outside the container, comprising a hydrogen tank, and a hydrogen pipe connecting the first chamber and the hydrogen tank;
An oxygen storage unit provided outside the container and comprising an oxygen tank and an oxygen pipe connecting the second chamber and the oxygen tank;
Circulating water discharged from the container passes through the fuel cell and the water electrolyzer, and is fed to the first chamber, and hydrogen is fed to the first chamber. Tube,
Circulating water discharged from the container passes through the fuel cell and the water electrolyzer, and is supplied to the second chamber, and oxygen is supplied to the second chamber. Tube,
One end is connected to the first feed pipe downstream from the fuel cell, and a hydrogen supply pipe for supplying hydrogen from the first chamber to the fuel cell;
A power storage device comprising: one end connected to the second supply pipe downstream from the fuel cell, and an oxygen supply pipe for supplying oxygen from the second chamber to the fuel cell.   The power storage device according to claim 1, wherein at least one of the hydrogen pipe and the oxygen pipe is arranged to supply hydrogen or oxygen into the circulating water stored in the container.

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