JP2022133348A - Water electrolysis method, water electrolysis apparatus, water electrolysis system, operational method of water electrolysis and fuel cell, water electrolysis and fuel cell apparatus, and water electrolysis and fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To administer a suitable water electrolysis treatment by flowing a large amount of raw water for water electrolysis into the reaction area of a water electrolytic cell while suppressing the power of a pump.

SOLUTION: A water electrolytic cell 10 comprises a separator 31 situated on the hydrogen-electrode side and a separator 41 situated on the oxygen-electrode side, which are provided on both sides of an electrode body 21 comprising power feeders arranged on both sides of an electrolyte film. The water electrolytic cell 10 is rectangular, placed oblongly to the vertical direction, and laminated in the horizontal direction. The raw water for water electrolysis is supplied from connecting holes 24, 34, and 44 that are arranged along the lower long side of the water electrolytic cell 10 toward connecting holes 23, 33, and 43 that are arranged along the upper long side.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention provides a water electrolysis method, a water electrolysis apparatus, a water electrolysis system, and water electrolysis/fuel cell operation using a solid polymer water electrolysis fuel cell integrated cell. The present invention relates to a method, a water electrolysis/fuel cell device, and a water electrolysis/fuel cell system.

Conventionally, a plurality of solid polymer type water electrolysis cells, in which power feeders are arranged on both sides of an electrolyte membrane and separators are arranged on the outside of each cell, are stacked and used as a water electrolysis device (Patent Document 1). .

More specifically, the technique of Patent Document 1 aims to distribute the raw water for water electrolysis evenly to the water flow channels and to uniformly and reliably supply the raw water to the entire water flow channels to perform water electrolysis. Therefore, the water electrolysis cells are arranged horizontally and stacked vertically. Specifically, a plurality of inlet connecting channels are provided for communicating the water supply communicating holes and the water channels, and the water supply communicating hole includes a communicating hole inner wall surface to which the plurality of inlet connecting channels open and the The outer wall surface of the communication hole facing the inner wall surface of the communication hole has an elongated elliptical opening cross section.

As a result, the raw water is evenly branched from the oblong water supply passage to a plurality of inlet connection passages, and then supplied to the water passage. It was designed to prevent water from flowing preferentially on the side. As a result, the occurrence of variations in pressure loss within the water flow path is suppressed, and water is evenly distributed over the entire water flow path.

JP 2011-127209 A

However, the above-described prior art aims to distribute the raw water for water electrolysis evenly to the water flow passages and uniformly and reliably supply the raw water to the entire water flow passages to carry out the water electrolysis treatment. There is no particular suggestion about the pressure loss based on the length of the flow path, and in order to flow a large amount of raw water to each water electrolysis cell, it is necessary to raise the pressure of the pump that supplies raw water separately. was there.

The present invention has been made in view of such a point, and an object of the present invention is to perform a suitable water electrolysis treatment by flowing a large amount of raw water for water electrolysis into the reaction area of the cell while suppressing the power of the pump.

In order to achieve the above object, the present invention provides a water electrolysis apparatus in which a plurality of solid polymer type water electrolysis cells are laminated, in which power feeders are arranged on both sides of an electrolyte membrane and separators are placed outside each power feeder. wherein the solid polymer type water electrolysis cell is rectangular, and the water electrolysis cell is horizontally long and vertically arranged and horizontally stacked, The raw material water is supplied into the water electrolysis cell from the lower long side of the rectangular water electrolysis cell toward the upper long side of the water electrolysis cell.

According to the present invention, the solid polymer type water electrolysis cell is rectangular, and the water electrolysis cell is arranged horizontally and vertically. Since the raw material water is supplied into the water electrolysis cell from the long side toward the upper long side, for example, under the same reaction area, the raw material is supplied from the lower long side of the water electrolysis cell. When water is supplied toward the opposite long side, the flow path length is in the short side direction, so the supply source (supply port) for supplying water can be elongated in the longitudinal direction. It can increase the flow rate of water. Since the length of the flow path is in the short side direction, the reaction flow path is shortened, and the pressure loss can be kept low. Therefore, it is possible to supply a large amount of raw water to the reaction area of the cell while suppressing the power of the pump that supplies the raw water.

According to another aspect of the present invention, there is provided a water electrolysis apparatus in which a plurality of solid polymer type water electrolysis cells each having a power feeder disposed on both sides of an electrolyte membrane and a separator disposed outside each power feeder are laminated, The solid polymer type water electrolysis cells are rectangular, and the water electrolysis cells are arranged horizontally and vertically, and are stacked horizontally. A communication port for supplying water is arranged on the side, and a communication port for discharging electrolyzed water and oxygen gas is arranged on the upper long side of each water electrolysis cell.

In the water electrolysis device having such characteristics, a communication port for discharging hydrogen gas may be arranged on the short side of each of the rectangular water electrolysis cells.

Furthermore, it is preferable to use a separator in which a flow path through which a fluid can flow is formed both in the vertical direction and in the horizontal direction. As such a separator, known materials such as an embossed plate, mesh, punching metal, etc. can be used as its constituent material.

According to still another aspect, the present invention provides a water electrolysis system using such a water electrolysis device, wherein the water electrolysis device (directly, power feeders on both sides of the electrolyte membrane) On the other hand) a power supply unit that supplies DC power, a raw water supply channel that supplies raw water to the water electrolysis device, a hydrogen gas discharge channel that releases hydrogen gas generated in the water electrolysis device to the outside of the system, and and an oxygen gas discharge path for discharging oxygen gas generated in the water electrolysis device to the outside of the system.

Furthermore, in view of the characteristics of the water electrolysis cell employed in the water electrolysis method, the water electrolysis device, and the water electrolysis system, the following invention can be proposed.

First, water electrolysis is performed by stacking multiple solid polymer type water electrolysis fuel cell integrated cells, in which power supply/current collectors are arranged on both sides of the electrolyte membrane, and separators are further arranged on the outside of each power supply/current collector. - A method of switching between water electrolysis operation and fuel cell operation using a fuel cell device, wherein the solid polymer type water electrolysis fuel cell integrated cell is rectangular, and the water electrolysis fuel cell The body-shaped cells are arranged horizontally and vertically, and are stacked horizontally. The raw material water is supplied into the water electrolysis fuel cell integrated cell toward the side, and when the fuel cell is operated, it is directed from the short side of the rectangular water electrolysis fuel cell integrated cell to the opposite short side A water electrolysis/fuel cell operating method, characterized by supplying a source gas into a water electrolysis/fuel cell integrated cell.

From another point of view, a solid polymer type water electrolysis fuel cell integrated cell is provided in which feeders and current collectors are arranged on both sides of an electrolyte membrane, and separators are further arranged outside each of the feeders and collectors. A water electrolysis/fuel cell device in which a plurality of layers are stacked, wherein the solid polymer type water electrolysis fuel cell integrated cells are rectangular, and the water electrolysis fuel cell integrated cells are horizontally long and arranged in a vertical direction. , and stacked in the horizontal direction, and on the lower long side of each of the rectangular water electrolysis fuel cell integrated cells, a communication port for supplying raw material water during water electrolysis operation and a cooling water supply A communication port for discharging electrolyzed water and oxygen gas during water electrolysis operation is disposed on the upper long side of each water electrolysis fuel cell integrated cell, and each water electrolysis fuel cell A communication port for discharging hydrogen gas during water electrolysis operation, a communication port for supplying hydrogen gas during fuel cell operation, and a communication port for supplying air or oxygen gas are formed on the short side of the integrated cell. It is possible to propose a water electrolysis/fuel cell device characterized by:

In this case, it is preferable to use a separator in which a flow path through which a fluid can flow is formed in both the vertical direction and the horizontal direction. For this separator, a known separator such as an embossed plate, mesh, punching metal, etc., as described above, can be used.

Furthermore, in such a water electrolysis/fuel cell device, a communication port through which air or oxygen gas and reaction product water are discharged is formed on the short side of the water electrolysis fuel cell integrated cell. The lowermost part of the communication port through which the air or oxygen gas and reaction product water are discharged may be located below the lowermost part of the electrode surface.

As a water electrolysis/fuel cell system using such a water electrolysis/fuel cell device, for example, the following can be proposed. That is, a power supply unit for supplying direct current power to the water electrolysis/fuel cell device, a raw water supply line for supplying raw material water to the water electrolysis/fuel cell device, and hydrogen gas generated in the water electrolysis/fuel cell device. to the outside of the system, an oxygen gas release path to release the oxygen gas generated in the water electrolysis/fuel cell device to the outside of the system, and hydrogen to supply hydrogen gas to the water electrolysis/fuel cell device a gas supply channel, a gas supply channel for supplying oxygen gas or air to the water electrolysis/fuel cell device, and an oxygen gas release channel for releasing water generated in the water electrolysis/fuel cell device outside the system. A water electrolysis/fuel cell system characterized by:

According to the present invention, it is possible to supply a large amount of raw material water to the reaction area of the cell while suppressing the power of the pump that supplies the raw material water, and it is possible to perform suitable water electrolysis treatment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing an outline of a system of a water electrolysis system incorporating a water electrolysis cell stack according to an embodiment; 1 is an exploded perspective view of a water electrolysis cell used in a water electrolysis cell stack according to an embodiment; FIG. FIG. 4 is a front view of the oxygen electrode side separator showing how fluid flows on the oxygen electrode side separator in the water electrolysis cell stack according to the embodiment. FIG. 4 is a front view of the hydrogen electrode side separator showing how fluid flows on the hydrogen electrode side separator in the water electrolysis cell stack according to the embodiment. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing an outline of a system of a water electrolysis/fuel cell system incorporating a stack of water electrolysis/fuel cell cells according to an embodiment; FIG. 4 is an exploded perspective view showing how fluid flows during water electrolysis operation in the solid polymer integrated cell used in the water electrolysis/fuel cell stack according to the embodiment. FIG. 2 is an exploded perspective view showing how fluid flows during operation of the fuel cell in the solid polymer integrated cell used in the water electrolysis/fuel cell stack according to the embodiment. 4 is a graph showing the ratio of channel pressure loss to the aspect ratio of electrodes. In the separator in the solid polymer integrated cell, the communication port for discharging air and reaction product water is set to be positioned below the lowest part of the electrode surface and the lowermost part of the sealing material. It is an explanatory view of the front side showing the state of the.

1 shows a schematic configuration of a water electrolysis system 1 according to an embodiment of the present invention. In this water electrolysis system 1, solid polymer water As a water electrolysis device, a plurality of electrolysis cells (unit cells) 10 are erected in the vertical direction, connected in series in the horizontal direction, stacked, and sandwiched between end plates 11 and 12 from both sides. of water electrolysis cell stack 13 .

As shown in FIG. 2, the water electrolysis cell 10 includes an electrode body 21 having a structure in which an electrolyte membrane is sandwiched between current collectors from both sides, a separator 31 on the hydrogen electrode side sandwiching the electrode body 21 from both sides, an oxygen It has a separator 41 on the pole side.

The electrode body 21, the separator 31 on the hydrogen electrode side, and the separator 41 on the oxygen electrode side have an electrode portion 22 and regions 32 and 42 corresponding to the electrode portion 22 in the center, respectively. Communicating holes 23 , 24 , 33 , 34 , 43 , 44 are formed above and below the electrode portion 22 and regions 32 , 42 . These communication ports 23, 24, 33, 34, 43, 44 function as manifolds for electrolyzed water and oxygen gas generated by water electrolysis. The horizontal lengths of the communication ports 23 , 24 , 33 , 34 , 43 , 44 are set to the same lengths as the electrode portion 22 and the regions 32 , 42 .

In the electrode assembly 21, the hydrogen electrode side separator 31, and the oxygen electrode side separator 41, the central electrode portion 22 and regions 32, 42 corresponding to the electrode portions 22, respectively, are located below one side of the outer side (in the present embodiment, in FIG. 2), vertical communication ports 25, 35, and 45 functioning as manifolds for hydrogen gas generated during water electrolysis are formed, respectively.

As for the separator 31 on the hydrogen electrode side, sealing materials 36 and 37 (indicated by dashed lines) are arranged around the back surface of the communication ports 33 and 34 so as to independently surround the communication ports 33 and 34, respectively. there is A sealing material 38 (indicated by broken lines) is arranged so as to surround the rear surface of the central region 32 and the rear surface of the communication port 35 together. As for the separator 41 on the oxygen electrode side, a sealing material 46 is disposed so as to surround the central region 42 and the communication ports 43 and 44 together, and a sealing material 47 is disposed so as to independently surround only the communication port 45. It is provided on the outer circumference of the communication port 45 . These sealing materials 36 to 38, 46, and 47 prevent each fluid from flowing out of paths other than predetermined paths.

Further, in the present embodiment, at least the central regions 32 and 42 serving as reaction channels in the separator 31 on the hydrogen electrode side and the separator 41 on the oxygen electrode side are configured with general straight channels or serpentine channels. In contrast to the materials used, materials such as embossed plates, meshes, punching metals, etc. are used to form a large number of irregularities on the surface. As a result, the separator 31 on the hydrogen electrode side and the separator 41 on the oxygen electrode side are provided with channels through which fluid can flow both in the vertical direction and the horizontal direction.

As described above, a plurality of water electrolysis cells (unit cells) 10 having the above configuration are vertically erected, and as shown in FIG. A water electrolysis cell stack 13 is configured by connecting and stacking in series and sandwiched between end plates 11 and 12 from both sides.

Next, returning to FIG. 1, the water electrolysis system 1 employing this water electrolysis cell stack 13 will be described. A pure water inlet port P<b>1 of the water electrolysis cell stack 13 is supplied with raw water, such as pure water. Specifically, raw water (pure water) is supplied from a tank 51 having a gas-liquid separation function on the oxygen side to a pure water inlet port P1 serving as a raw water inlet of the water electrolysis cell stack 13. Electrolytic operation is performed.

More specifically, a pipe 52 is connected between the bottom of the tank 51 and the pure water inlet port P1 of the water electrolysis cell stack 13 . Pure water as raw water is supplied from the tank 51 to the pure water inlet port P1 of the water electrolysis cell stack 13 by a pump 53 provided in the pipe 52 . The pipe 52 is provided with a check valve 54 downstream of the pump 53 , and further downstream with a pressure gauge 55 for measuring the pressure inside the pipe 52 . The pure water inlet port P1 communicates with the communication ports 24, 34, 44 shown in FIG.

A return pipe 56 for returning part of the water flowing in the pipe 52 to the tank 51 is connected to the pipe 52 on the downstream side of the pump 53. The return pipe 56 includes a flow control valve V1, a heat An exchanger 57, an ion exchange resin tower 58, and a filter 59 are provided, and the quality of the water in the tank 51 is maintained by treating the return water through these devices. The tank 51 is provided with a liquid level sensor 51a for detecting the water level in the tank. The tank 51 is replenished with pure water as raw material water from an external pure water supply source (not shown) through a pipe 60 based on a signal from the liquid level sensor 51a. Oxygen gas remaining in the air layer inside the tank 51 is discharged to the outside or to an external demand destination through the pipe 63 .

The raw water supplied to the water electrolysis cell stack 13 from the pure water inlet port P1 through the pipe 52 is electrolyzed in the water electrolysis cell stack 13, and oxygen and water accompanied by oxygen are converted into pure water serving as an oxygen-side outlet. It is returned to the tank 51 through the pipe 61 from the outlet port P2, and gas-liquid separation is performed in the tank 51. The pipe 61 is provided with a pressure gauge 62 for measuring the pressure inside the pipe 61 and an electromagnetic valve V2. The pure water outlet port P2 communicates with the communication ports 23, 33, 43 shown in FIG.

A hydrogen outlet port P3 serving as a hydrogen side outlet of the water electrolysis cell stack 13 is connected to a pipe 71, and this pipe 71 communicates with a tank 72 having a gas-liquid separation function on the hydrogen side. The hydrogen outlet port P3 communicates with the communication ports 25, 35 and 45 shown in FIG.

Between the tank 72 and the gas layer part of the tank 51 (the part above the liquid level of the water stored in the tank, the part where the liquid level does not reach even if the stored liquid level rises) , a pipe 73 is connected. The pipe 73 is provided with an electromagnetic valve V3 and a valve V4. A liquid level sensor 72a is provided in the tank 72 to detect the water level in the tank.

As described above, the hydrogen generated by water electrolysis is sent to the tank 72 through the pipe 71 together with the accompanying water, and gas-liquid separation is performed in the tank 72 . The hydrogen gas after gas-liquid separation in the tank 72 is sent through a pipe 74 to, for example, a demand side or a hydrogen storage tank (high-pressure container, not shown). A back pressure valve V5 is provided in the pipe 74, and a discharge pipe 75 is connected to the upstream side of the back pressure valve V5 in the pipe 74. The discharge pipe 75 is provided with an electromagnetic valve V6.

A DC power supply 2 is connected to the water electrolysis cell stack 13, and the pure water for electrolysis supplied from the pure water inlet port P1 is electrolyzed into hydrogen ions and oxygen ions in accordance with the output thereof. Among them, oxygen ions become oxygen molecules on the catalyst in the water electrolysis cell 10, and as described above, are discharged out of the cell together with the pure water from the pure water outlet port P2. Along with this, it moves to the hydrogen side in the water electrolysis cell 10, becomes hydrogen molecules on the hydrogen side catalyst, and is discharged out of the cell from the hydrogen outlet port P3.

According to the water electrolysis system 1 having the above configuration, the pure water supplied from the pure water inlet port P1 to each water electrolysis cell 10 of the water electrolysis cell stack 13 by the electric power from the DC power supply 2 is supplied to each water electrolysis cell. At 10, water is electrolyzed, and oxygen molecules are discharged from the pure water outlet port P2 together with the pure water. At this time, as shown in FIG. Pure water, which is raw material water, flows from the lower communication port 44 communicating with the pure water inlet port P1 to the upper communication port 43 communicating with the pure water outlet port P2. On the other hand, in the separator 31 on the hydrogen electrode side, as shown in FIG. 4, the generated hydrogen gas flows diagonally through the central region 32 toward the communication port 35 (arrows in the figure).

Here, the main requirements for the reaction channel of the water electrolysis cell 10 are that the reaction channel pressure loss of the oxygen electrode is low from the viewpoint of reducing the power of the pump 53 and the pressure difference between upstream and downstream of the channel; From the viewpoint of supplying sufficient pure water to the surface, ensuring the cooling function of the cell, and preventing water drying up downstream of the flow path due to an increase in the void ratio (ratio of air bubbles in the pure water), supply pure water. It is necessary to ensure sufficient flow rate.

In light of this point, looking at the flow of the reaction fluid in the oxygen electrode side separator 41 shown in FIG. Arrows in the figure), the oxygen molecules generated in the central region 42 corresponding to the electrode portion 22 are discharged from the upper communication port 43 together with the electrolyzed water that has not undergone water electrolysis (pure water subjected to water electrolysis). It flows to the outlet port P2. Therefore, considering the same reaction area, as shown in the embodiment, the region 42 and the separator 41 are oblong rectangles, and the communication port 44 serving as the pure water supply port is located on the long side. Since the supply port extends along the longitudinal direction, the length of the communication port 44 can be ensured long, and a large amount of pure water, which is raw material water, can flow into the region 42 . Moreover, since the channel length is in the direction of the short side, the pressure loss in the reaction channel when flowing through the regions 32 and 42 corresponding to the electrode portion 22 is kept low.

On the other hand, in the water electrolysis cell 10, since the supplied electrolyzed water also plays a role of cooling the cell, increasing the flow rate of supplied pure water is also advantageous for cooling the cell. If the flow rate of the electrolyzed water is too low, the heat generated during the reaction cannot be sufficiently removed, and there is a risk of abnormal overheating and damage to the cell. In addition, when the cooling is insufficient, a large temperature change may occur upstream and downstream of the water electrolysis cell 10. However, according to the water electrolysis cell 10 of the embodiment, the pure water flow rate can be increased and the flow rate can be increased. The short length of the road can limit such situations.

In the water electrolysis cell 10 of the embodiment, only one communication port 25, 35, 45 is provided for discharging hydrogen gas for simplification of the system. If desired, communication ports communicating with the hydrogen outlet port P3 may be appropriately increased on both sides of the electrode portion 22 and the regions 32 and 42 .

Further, the vertical position of the communication port for discharging hydrogen gas may be vertically long so as to completely cover the electrode surface from the lower part to the upper part (that is, it may be positioned substantially corresponding to the short sides of the separators 31 and 41). length may be set). However, in that case, a large amount of hydrogen will remain in the communication port portion during operation, and the amount of hydrogen gas in the water electrolysis cell stack 13 will increase. Therefore, from the viewpoint of safety, it is better to reduce the size of the communication port 35 for discharging hydrogen gas and reduce the amount of hydrogen remaining in the water electrolysis cell stack 13 .

As a method of arrangement, for example, the communication port 35 is provided only in the lower part of the electrode surface, and the external pipe 71 communicating with the communication port 35 is provided at a position lower than the lower end of the electrode surface 22, The coordination water may be smoothly discharged. In order to keep the electrolyte membrane moist, the communication port 35 is provided on the upper side of the electrode surface 22, and the external pipe 71 is provided at a position higher than the upper end of the electrode surface 22 so that the electrode surface 22 is submerged. You may do so.

The above is an example of the water electrolysis system 1 using the polymer electrolyte water electrolysis cell 10, but the solid polymer integrated type in which the polymer electrolyte water electrolysis cell and the fuel cell are integrated. Cells (also called water electrolysis fuel cell integrated cells, integrated cells, or reversible cells) have had the following problems.

That is, the solid polymer type integrated cell is an energy converter that integrates a solid polymer type water electrolysis cell and a fuel cell and selectively exhibits the functions of both in one cell. As described above, in the water electrolysis cell, pure water is supplied to the reaction channel of the oxygen generating electrode, and electric power is supplied from the outside to electrolyze the pure water. Oxygen is generated at the oxygen generating electrode and hydrogen is generated at the hydrogen generating electrode, which are separated by a solid polymer diaphragm. The generated hydrogen is discharged out of the cell through the reaction channel of the hydrogen generating electrode and, if necessary, is stored in a storage container or supplied directly to hydrogen demand. At this time, not all of the pure water supplied to the reaction channel of the oxygen generating electrode is decomposed into hydrogen and oxygen. discharged outside.

On the other hand, in the fuel cell, hydrogen is introduced into the reaction channel of the hydrogen electrode (the hydrogen generating electrode of the water electrolysis cell; hereinafter sometimes referred to as the "hydrogen electrode"), and the oxygen electrode (the oxygen generating electrode of the water , Oxygen electrode) is supplied with oxygen-containing gas such as air or oxygen in a humidified state as necessary, and power is generated by connecting a load to the outside.

Along with such power generation, water is produced at the oxygen electrode, and is discharged out of the cell through the reaction channel together with air and oxygen that have not been used in the reaction. Also on the hydrogen electrode side, water generated in the cell is discharged out of the cell through the reaction channel together with hydrogen not used in the reaction.

As with the water electrolysis cell described above, ordinary water electrolysis cells and fuel cells are in the form of stacks in which multiple unit cells are stacked. When the reaction fluid is discharged from the cell to the outside of the cell, it is carried out through a communication port functioning as a manifold connecting the outside of the cell and the reaction channel. Conventionally, this communication port is common to each electrode of the water electrolysis cell and the fuel cell (for example, Japanese Unexamined Patent Application Publication No. 2006-127807).

Here, the main requirements for the reaction channel of the water electrolysis cell are, as mentioned earlier, low pressure loss in the reaction channel of the oxygen electrode from the viewpoint of reducing the pump power and reducing the pressure difference between upstream and downstream of the channel. In addition, it is possible to increase the supply flow rate of pure water from the viewpoint of sufficiently supplying pure water to the electrode surface, ensuring the cooling function of the cell, and preventing water drying up downstream of the flow path due to an increase in void fraction. On the other hand, the main requirements for the reaction channel of the fuel cell are the improvement of the diffusibility of oxygen to the electrode surface and the prevention of clogging of the reaction channel by generated water. It is to increase the flow velocity.

In this case, in order to secure the requirements for the oxygen electrode reaction channel of the water electrolysis cell, it is necessary to increase the cross-sectional area of the channel. Therefore, it is necessary to reduce the flow channel cross-sectional area. Further, the pure water supplied to the oxygen electrode of the water electrolysis cell and the humidified air (oxygen) supplied to the oxygen electrode of the fuel cell differ in density by about 1,000 times. Therefore, if pure water and humidified air are flowed at the same flow rate, the pressure loss when water is flowed will be overwhelmingly larger. In other words, there are contradictory requirements for both reaction channels, particularly for the reaction channel of the oxygen electrode, and it is important how to satisfy them.

In this respect, conventionally, the reaction channel was designed according to the more important function of water electrolysis and the fuel cell, or the reaction channel was designed around the midpoint between the needs of both. Therefore, the optimum reaction channel design for both has not been made.

In view of this point, the communication port of the oxygen electrode (functioning as a manifold), which has been commonly used for the water electrolysis cell and the fuel cell, will be replaced with the communication port of the oxygen electrode of the water electrolysis cell (functioning as a manifold). ) and the communication port (functioning as a manifold) for the oxygen electrode of the fuel cell, respectively, to solve such a problem.

FIG. 5 shows an outline of the configuration of a water electrolysis/fuel cell system 101 according to the embodiment. A plurality of cells 110 are erected in the vertical direction, connected in series in the horizontal direction, stacked, and sandwiched between end plates 111 and 112 from both sides. has a stack 113

FIG. 6 shows an integrated cell 110 in which a water electrolysis cell and a fuel cell are integrated according to the embodiment. Note that FIG. 6 also shows the flow of the fluid when explaining the flow of the fluid during the water electrolysis operation later.

The integrated cell 110 includes an electrode body 121 having a configuration in which an electrolyte membrane is sandwiched between supply and collectors on both sides, and a separator 131 on the hydrogen electrode side and a separator 141 on the oxygen electrode side that sandwich the electrode body 121 from both sides. have.

The electrode body 121, the separator 131 on the hydrogen electrode side, and the separator 141 on the oxygen electrode side have, respectively, a central electrode portion 122, a rear surface of the region 132 corresponding to the electrode portion 122, and various communication elements described below on the outside of the region 142. It has a mouth.

First, the electrode part 122 in the rectangular electrode body 121, the separator 131 on the hydrogen electrode side, and the separator 141 on the oxygen electrode side. , 133a, 133b, 143a, 143b are provided. Similarly, the rectangular electrode body 121, the hydrogen electrode side separator 131, the electrode portion 122 in the oxygen electrode side separator 141, and the regions 132 and 142 corresponding to the electrode portions are provided on both outer sides of the oxygen electrode for the fuel cell. Communication ports 124a, 124b, 134a, 134b, 144a, 144b are provided.

On the other hand, the electrode portion 122 of the rectangular electrode body 121, the hydrogen electrode side separator 131, and the oxygen electrode side separator 141, and below the regions 132 and 142 corresponding to the electrode portion 122, are provided with cooling water communication ports 125a, respectively. , the oxygen electrode communication port 126a, the cooling water communication port 135a, the oxygen electrode communication port 136a, the cooling water communication port 145a, and the oxygen electrode communication port 146a are provided alternately. Further, in the electrode body 121, the hydrogen electrode side separator 131, and the oxygen electrode side separator 141, the electrode portion 122 and the regions 132 and 142 corresponding to the electrode portion 122 are provided above the outside of the regions 132 and 142, respectively, the oxygen electrode communication port 126b and the cooling water. The oxygen communication port 125b, the oxygen electrode communication port 136b, the cooling water communication port 135b, the oxygen electrode communication port 146b, and the cooling water communication port 145b are provided alternately.

Sealing materials are arranged around the communication openings of the separator 131 on the hydrogen electrode side and the separator 141 on the oxygen electrode side, as described below. First, as for the separator 131 on the hydrogen electrode side, a sealing material 137 (indicated by a dashed line) surrounding each of the oxygen electrode communication ports 134a and 134b is arranged independently on the outer periphery of the oxygen electrode communication ports 134a and 134b. A sealing material 138 (indicated by broken lines) is arranged around the hydrogen electrode communication ports 133a and 133b and the central region 132 to integrally surround them. Sealing materials 139 (indicated by dashed lines) are arranged around the cooling water communication ports 135a and 135b and the oxygen electrode communication ports 136a and 136b, respectively, to independently surround them.

On the other hand, regarding the separator 141 on the oxygen electrode side, sealing materials 147 are arranged independently around the oxygen electrode communication ports 143a and 143b for the fuel cell. Sealing materials 148 are arranged around the cooling water communication ports 145a and 145b so as to surround the respective communication ports independently. A sealing material 149 is arranged to integrally surround the remaining oxygen electrode communication ports 146a and 146b and the central region 142. As shown in FIG.

These sealing materials 137 to 139 and 147 to 149 prevent each fluid from flowing outside of a predetermined path. Further, in the present embodiment, at least the central regions 132 and 142, which serve as reaction channels, of the separator 131 on the hydrogen electrode side and the separator 141 on the oxygen electrode side are configured with general straight channels or serpentine channels. In contrast to the materials used, materials consisting of embossing, mesh, perforated metal, etc. are used. As a result, flow paths are formed in the separator 131 on the hydrogen electrode side and the separator 141 on the oxygen electrode side so that the fluid can flow in both the vertical direction and the horizontal direction.

Next, referring back to FIG. 5, the water electrolysis/fuel cell system 101 employing the water electrolysis/fuel cell stack 113 in which the integrated cells 110 are stacked will be described. In FIG. 5, the configuration of members, devices, etc. specified by the same reference numerals as those used in the explanation of FIG. Therefore, redundant description is omitted.

As described above, the integrated cell 110 employed in this water electrolysis/fuel cell system 101 has many types of communication ports that function as manifolds. The number of ports provided in 113 is also increased. Specifically, first, the pure water inlet port P1 communicates with the oxygen electrode communication ports 126a, 136a, and 146a, the pure water outlet port P2 communicates with the oxygen electrode communication ports 126b, 136b, and 146b, and the hydrogen outlet port P3 communicates with the hydrogen electrode. It communicates with the communication ports 123b, 133b, and 143b. Since the water electrolysis/fuel cell system 101 is capable of fuel cell operation, a hydrogen inlet port P4 is newly provided as an introduction port for hydrogen gas, which is a raw material gas.

The hydrogen inlet port P4 communicates with the hydrogen electrode communication ports 123a, 133a and 143a. Furthermore, an air inlet port P5 communicating with oxygen electrode communication ports 124a, 134a, 144a for fuel cells is provided, and an air outlet port P6 communicating with oxygen electrode communication ports 124b, 134b, 144b for fuel cells is provided. . Furthermore, a cooling water outlet port P7 communicating with the cooling water communication ports 125a, 135a and 145a and a cooling water inlet port P8 communicating with the cooling water communication ports 125b, 135b and 145b are newly provided.

A flow path 151 is connected to the hydrogen inlet port P4, and hydrogen gas from a hydrogen gas supply source (not shown) can be introduced into the hydrogen inlet port P4. The flow path 151 is provided with a regulating valve V7, an electromagnetic valve V8, and a pressure gauge 152. As shown in FIG. A flow path 153 communicating with the gas layer of the tank 72 is connected to the downstream side of the solenoid valve V8 in the flow path 151 . A hydrogen pump 154 is provided in the flow path 153 .

A flow path 163 through which air supplied by a blower 161 is introduced via a humidity exchanger 162 is connected to the air inlet port P5. A check valve 164 is provided in the flow path 163 . A flow path 165 is connected to the air outlet port P6 so that air coming out of the water electrolysis/fuel cell stack 113 is discharged to the outside through the humidity exchanger 162 . The flow path 165 is provided with an electromagnetic valve V9.

A pipe 181 is connected to the cooling water outlet port P7, and the cooling water whose temperature has risen is sent to a heat exchanger 183 by a hydrogen pump 182, where it is heat-exchanged with cooling water from the outside, and after the temperature is lowered, it is discharged to the pipe. Through 184, the cooling water is introduced into the water electrolysis/fuel cell stack 113 from the cooling water inlet port P8. As for the water source of the cooling water, for example, city water such as tap water, ground water, or the like can be used. Also, the cooling water whose temperature has been raised after heat exchange may be appropriately supplied to a heat demand destination.

In addition to the direct-current power supply 2 , a power load 3 is connected to the water electrolysis/fuel cell stack 113 .

The water electrolysis/fuel cell system 101 is configured as described above, and the operation method thereof will now be described.

[Water electrolysis operation]
First, the solenoid valve V2 is opened, and the other solenoid valves V3, V6, V8 and V9 are closed. The pure water stored in the tank 51 is supplied to the pure water inlet port P1 of the water electrolysis/fuel cell stack 113 through the pipe 52 by activating the pump 53 . The pure water inlet port P1 communicates with the oxygen electrode communication ports 126a, 136a and 146a, and as shown in FIG. Through the region 142, the oxygen electrode communication ports 126b, 136b, and 146b are discharged from the pure water outlet port P2 to the outside of the water electrolysis/fuel cell stack 113, and the water is returned to the tank 51 through the pipe 61. .

When DC power is supplied from the DC power source 2 to the water electrolysis/fuel cell stack 113 in this state, protons (H ⁺ ) and oxygen are generated on the oxygen electrode. The generated protons (H ⁺ ) move through the electrode body 121 from the oxygen electrode to the hydrogen electrode accompanied by coordination water, and pass through the region 132 of the separator 131 as shown in FIG. 133b to the outside of the water electrolysis/fuel cell stack 113 from the hydrogen outlet port P3. In the tank 72, the hydrogen gas separated into gas and liquid is sent through the pipe 71 to the back pressure valve V5, where the pressure is adjusted and then sent to the hydrogen demand destination or hydrogen storage tank (not shown) outside the system. be done.

The pure water separated in the tank 72 is sent to the tank 51 through the pipe 73 using the pressure difference between the hydrogen side and the oxygen side. An existing known technique may be used to feed the pure water in the tank 72 to the tank 51 .

On the other hand, the oxygen generated in the water electrolysis/fuel cell stack 113, together with undecomposed pure water, passes through the communication ports 126b, 136b, and 146b via the pure water outlet port P2 and then through the pipe 61 to the tank 51. water is returned to The oxygen gas separated into gas and liquid in the tank 51 is discharged outside the system through the pipe 63 . If oxygen gas is required, an oxygen storage tank (not shown) may be provided separately and sent to the oxygen storage tank. The pure water separated in the tank 51 is again supplied to the water electrolysis/fuel cell stack 113 as pure water for electrolysis.

As described above, the pipes 181 and 184 are cooling water systems and serve to remove heat generated by electrolysis. The removed heat may be supplied to the thermal demand via heat exchanger 183, as previously described. However, in the case of water electrolysis operation, cooling is possible with electrolyzed water (pure water) for electrolysis, so cooling water does not need to be circulated.

[Fuel cell operation]
Next, the case of fuel cell operation will be described. During fuel cell operation, the solenoid valves V8 and V9 are opened and the other solenoid valves V2, V3 and V6 are closed. On the hydrogen side, hydrogen pressure-regulated by the regulating valve V7 is supplied through the flow path 151 to the hydrogen inlet port P4. As shown in FIG. 7, the hydrogen supplied to the hydrogen inlet port P4 passes through the communication port 123a, the central electrode portion 122, and the hydrogen electrode communication port 123b and is discharged out of the cell from the hydrogen outlet port P3. By activating the hydrogen pump 154 here, the discharged hydrogen gas is sucked into the hydrogen pump 154 and supplied again to the water electrolysis/fuel cell stack 113 .

On the other hand, on the oxygen side, air is sucked from the atmosphere by activating the blower 161, and after it is appropriately humidified by the humidity exchanger 162, it passes through the pipe 163 and enters the water electrolysis/fuel cell stack from the air inlet port P5. 113. Since the air inlet port P5 communicates with the oxygen electrode communication port 144a, from the oxygen electrode communication port 144a, through the central region 142, from the communication port 144b, and from the air outlet port P6, the water electrolysis/fuel cell stack 113 discharged outside. Then, it is exhausted to the atmosphere through the pipe 165 and the humidity exchanger 162 . When the connection with the external power load 3 is turned on in this state, hydrogen is decomposed into protons on the hydrogen electrode, and protons and oxygen combine on the oxygen electrode to generate water and electricity. The generated electricity will be supplied to the power load 3 .

The hydrogen gas that has not been used in the reaction of the fuel cell operation is discharged from the hydrogen outlet port P3 to the outside of the water electrolysis/fuel cell stack 113 through the hydrogen electrode communication port 123b. supplied to The hydrogen gas separated into gas and liquid in the tank 72 is supplied again to the water electrolysis/fuel cell stack 113 by the hydrogen pump 154 . The amount of hydrogen consumed in the reaction is appropriately supplied from the outside at a constant pressure by the function of the regulating valve V7.

On the other hand, the air not used in the reaction and the water produced by the reaction pass through the communication port 144b and are discharged outside the water electrolysis/fuel cell stack 113 from the air outlet port P6. Then, it is sent to the humidity exchanger 162 via the pipe 165 . In the humidity exchanger 162, after humidifying the air sent from the blower 161, the humidified air is exhausted from the system through the pipe 165. Therefore, even if the air sent from the blower 161 is of low humidity, it is sufficiently humidified by the humidity exchanger 162 before being supplied to the water electrolysis/fuel cell stack 113 . It should be noted that circulation of cooling water in a cooling water system constituted by pipes 181 and 184 is essential for fuel cell operation.

When switching from the water electrolysis operation to the fuel cell operation, the power supply from the DC power supply 2 is first stopped. Next, on the hydrogen side, the solenoid valve V6 is opened to release the pressure of the entire hydrogen system to the outside and reduce the pressure in the system to near normal pressure. On the oxygen side, the pump 53 is stopped, the solenoid valve V2 is closed, the solenoid valve V9 is opened, and then the blower 161 is started to circulate the pure water remaining in the electrode portion 122 of the electrode body 121 and its surroundings. The air is discharged out of the water electrolysis/fuel cell stack 113 from the port 144b via the air outlet port P6. As for the subsequent method for drying the stack 113 of the water electrolysis/fuel cell stack 113, a conventional technique may be appropriately applied.

Also, when switching the operation from the fuel cell operation to the water electrolysis operation, the connection with the power load 3 is first cut off. Next, for the hydrogen side, after stopping the hydrogen pump 154, the electromagnetic valve V8 is closed. As for the oxygen side, after the blower 161 is stopped, the electromagnetic valve V9 is closed. After that, the water electrolysis operation should be started as usual.

Regarding the above water electrolysis operation and fuel cell operation, in the case of the conventional integrated cell, as described above, the communication port of the oxygen electrode was used in common during the water electrolysis operation and the fuel cell operation. The cross-sectional area and the length of the flow path when the reaction fluid was flowed were the same in both operation modes during the water electrolysis operation and the fuel cell operation. Therefore, as described above, it was impossible to satisfy the requirements for both reaction channels.

On the other hand, in the example using the integrated cell 110 according to the embodiment, it is possible to largely change the channel cross-sectional area and the channel length between the water electrolysis operation and the fuel cell operation.

That is, during the water electrolysis operation, as shown in FIG. 6, the reactant fluid in the separator 141 on the oxygen electrode side flows from the lower oxygen electrode communication port 146a to the upper oxygen electrode communication port 146b. Pure water, which is water, flows (arrows in the figure), and oxygen molecules generated in the central region 142 corresponding to the electrode portion 122 are electrolyzed water that has not undergone water electrolysis (pure water that has undergone water electrolysis). At the same time, it flows from the upper oxygen electrode communication port 146b to the pure water outlet port P2. Therefore, considering the same reaction area, as shown in the embodiment, the region 142 and the separator 141 are oblong rectangles, and the oxygen electrode communication port 146a serving as a pure water supply port has a long side Since the supply ports are arranged along the sides and extend in the longitudinal direction, a large number of supply ports can be secured, and a large amount of pure water, which is raw water, can flow to the electrode portion 122 and the region 142 . Moreover, since the channel length is in the lateral direction, the pressure loss in the reaction channel is kept low.

On the other hand, during fuel cell operation, it is necessary to reduce the cross-sectional area of the flow channel in order to ensure the requirements for the oxygen electrode reaction flow channel. Since it flows from the oxygen electrode communication port 144a located on the side to the oxygen electrode communication port 144b located on the opposite short side through the region 142, the cross-sectional area of the flow path is It is smaller than when flowing from the long side to the long side during water electrolysis operation. Similarly, hydrogen gas also flows from the communication port 123a located on the short side toward the hydrogen electrode communication port 123b located on the opposite short side. The area is smaller than during water electrolysis operation.

As described above, in the integrated cell 110 according to the embodiment of the present invention, the communication port of the oxygen electrode, which was conventionally used in common by the water electrolysis cell and the fuel cell, is replaced by the communication port of the oxygen electrode of the water electrolysis cell. and the communication port of the oxygen electrode of the fuel cell, and are provided exclusively for each. Furthermore, the electrode body 121 and the separators 131 and 141 are rectangular and horizontally long, and are arranged vertically. It is possible to flow the humidified air longitudinally while in fuel cell operation.

As a result, even though the same cell is used, the cross-sectional area of the reaction channel can be changed significantly between water electrolysis and fuel cell operation, and the length of the channel, which has a large impact on pressure loss, can be greatly increased. can be changed to As a result, the requirements required for the reaction flow path of the water electrolysis cell and the requirements required for the fuel cell can be satisfied under more ideal conditions even with the same cell.

In order to quantitatively demonstrate this, the extent to which pressure loss and flow velocity in the flow path can be changed between the conventional separator and the separator according to the embodiment with the same electrode shape will be shown below.

First, flow path pressure loss: ΔP is expressed by the following formula.
ΔP=λ・(L/D)・(ρ・v2/2) Equation (1)
In equation (1), λ is the pipe friction coefficient, L is the channel length, D is the channel cross-sectional area, ρ is the fluid density, and v is the flow velocity.

FIG. 8 shows an outline of how the flow path pressure loss changes when the aspect ratio of the electrodes is changed under the condition that the electrode area is fixed. The graph of FIG. 8 is the result of evaluation assuming that the value of the pipe friction coefficient is constant. When the aspect ratio (transverse direction X:longitudinal direction Y) of the electrodes is 1:2, the flow path pressure loss is 1/1 when the fluid is passed in the lateral direction as compared to when the fluid is passed in the longitudinal direction. It can be reduced by 16 times. Furthermore, when the aspect ratio of the electrodes is 1:4, the size can be reduced to 1/258 times. The pipe frictional resistance varies depending on the Reynolds number and whether the flow is laminar or turbulent, but the maximum difference is estimated to be about 5 times when the aspect ratio is about 1:4. By simple calculation, when the aspect ratio is 1:2, it can be reduced to 1/3 or less, and when it is 1:4, it can be reduced to 1/51 or less. Here, the density of gas and water differ by about 1000 times, but the flow rate of humidified air when actually operating a fuel cell with a conventional integrated cell is about 10 times the flow rate of pure water when water electrolysis is performed. be.

Considering these points, the difference in flow path pressure loss when humidified air is actually passed through the integrated cell and when pure water is passed is When the aspect ratio is 1:2, it becomes 3.3 times or less, and when the aspect ratio is 1:4, it becomes 1/5 times or less.

When the communication port is made common as in the conventional method, the difference in flow path pressure loss is 10 times greater when pure water is flowed than when humidified air is flowed regardless of the aspect ratio of the flow path (water density: 1,000 times the density of humidified air, and the flow rate of water: 1/10 times the flow rate of humidified air). . However, during water electrolysis operation, oxygen is generated at the oxygen electrode due to electrolysis, so the flow form of the oxygen electrode reaction channel is such that oxygen gas increases from a single-phase flow of pure water toward the cell outlet. A liquid two-phase flow is obtained. Since the channel pressure loss of gas-liquid two-phase flow is higher than that of single-phase flow, it is necessary to determine the aspect ratio of the channel in consideration of this point.

Next, how the flow velocity v in the channel changes when the aspect ratio of the electrodes is changed. Therefore, it can be obtained by a simple calculation of v=Q/A. The difference between flowing the flow rate Q in the lateral direction and the longitudinal direction is two times when the aspect ratio is 1:2, and four times when the aspect ratio is 1:4. From the analogy of mass transfer and heat transfer, the mass transfer coefficient increases in proportion to the 0.5th power of the flow velocity if the flow is laminar and to the 0.8th power of the flow velocity if the flow is turbulent. Therefore, if the flow velocity is 4 times, the material transfer rate is doubled when the flow is laminar flow and tripled when the flow is turbulent. In addition, the effect of discharging water produced by the reaction is increased.

If the diffusion of oxygen to the electrode surface is promoted, the fuel cell can be operated at a higher current density (=current value/electrode area) than before, and the power density per unit cell can be improved. Regarding this point as well, if the communication port is shared as before, and the cell is designed so that the pressure loss in the flow path during water electrolysis is small, the flow velocity will increase if the aspect ratio is 1:4. Since it becomes 1/4 times, the material transfer rate becomes 1/2 or 1/3 times, and the diffusion of oxygen to the electrode surface is not sufficiently performed, and the effect of discharging water produced by the reaction is also reduced. As a result, it can only be operated at lower current densities.

From the above, it can be seen that the channel pressure loss during water electrolysis and the flow velocity during fuel cell can be both reduced by the shape of the channel and the separator adopted in the integrated cell 110 of the embodiment of the present invention.

In the electrode body 121 and the separators 131 and 141 employed in the integrated cell 110 shown in FIGS. , 125b, 135a, 135b, 145a, and 145b are divided into a plurality of parts. This allows the fluid to be evenly distributed in the reaction channels. In addition to simply dividing the fluid into a plurality of parts, the vertically opposed communication ports are provided so that their uses are alternated, so that the fluid can be uniformly distributed in this respect as well.

By the way, in the above-described embodiment, the water electrolysis cell 10 and the integrated cell 110 are both arranged horizontally and vertically, and are stacked horizontally to form the water electrolysis cell stack 13 and the water electrolysis/fuel cell, respectively. However, if these rectangular cells are arranged vertically and raw material water etc. flow from the side (raw material water etc. flow from the long side), the following will be done. there is a problem. That is, when rectangular cells are arranged vertically and the raw material water, etc., is allowed to flow from the side, during water electrolysis operation, the pressure difference due to the water head pressure between the upper and lower parts of the cells increases (cell the lower part receives a lot of pressure). Therefore, it is necessary to design the entire cell so that it can withstand the strong pressure applied to the lower part of the cell. Therefore, it is preferable to install the cells horizontally so that the pressure difference received within the cells can be reduced.

In addition, when the fuel cell is operated, the water generated on both the oxygen side and the hydrogen side is drained from the electrode surface (by free fall due to gravity) through the manifold to the outside of the cell. At least one of the oxygen side and the hydrogen side flows upward, which hinders drainage. From this point of view as well, it is preferable that each of the rectangular cells described above be installed horizontally.

By the way, since the integrated cell 110 described above is used in an upright state (a state in which it is placed horizontally and stands vertically), the lower edge portion of the sealing material 149 shown in FIG. There is a possibility that reaction-generated water will accumulate in the area (indicated by the wavy line a in the figure). If the reaction product water accumulates in this manner and the electrode surface (the portion corresponding to the central region 142) is submerged, the electrode area that can contribute to the reaction is reduced, resulting in a drop in power generation efficiency.

In order to deal with such a situation, the oxygen electrode communication port 144b through which air and water produced by the reaction are discharged is located at the bottom of the electrode surface (indicated by the wavy line b in the figure) and the top of the sealing material 149 on the lower side ( ), that is, the lower edge of the oxygen electrode communication port 144b (indicated by the broken line d in the drawing) is located below the electrode surface indicated by the broken line b. It can be proposed to set the arrangement so that it is located below the lowest part and the uppermost part on the lower side of the sealing material 149 indicated by the broken line c.

As a result, the reaction product water does not reach the electrode surface and is discharged from the oxygen electrode communication port 144b without submerging the electrode surface. Therefore, it is possible to prevent the electrode from being submerged due to the accumulation of reaction product water, and prevent the electrode area from being reduced and the power generation efficiency from being lowered.

The present invention relates to water electrolysis using solid polymer water electrolysis cells in which power feeders are placed on both sides of an electrolyte membrane and separators are placed on the outside of each of them, and power feeders and current collectors are placed on both sides of the electrolyte membrane. Furthermore, it is useful for a water electrolysis fuel cell using solid polymer water electrolysis fuel cell integrated cells in which separators are arranged on the outside of each cell.

1 Water Electrolysis System 2 DC Power Supply 3 External Load 10 Water Electrolysis Cell 11, 12 End Plate 13 Water Electrolysis Cell Stack 21 Electrode Body 22 Electrode Part 23, 24, 25, 33, 34, 35, 43, 44, 45 Communication Port 31 Hydrogen electrode side separators 32, 42 Regions 36, 37, 38, 46, 47 Sealing material 41 Oxygen electrode side separators 51, 72 Tanks 52, 59, 74 Piping 53 Pump P1 Pure water inlet port P2 Pure water outlet port P3 Hydrogen Outlet port P4 Hydrogen inlet port P5 Air inlet port P6 Air outlet port P7 Cooling water outlet port P8 Cooling water inlet port 101 Water electrolysis/fuel cell system 101
110 integrated cell 111, 112 end plate 113 water electrolysis/fuel cell stack 121 electrode body 122 electrode part 123a, 123b, 133a, 133b, 143a, 143b hydrogen electrode communication port 124a, 124b, 134a, 134b, 144a, 144b Oxygen electrode communication port 131 Hydrogen electrode side separator 132, 142 Regions 137, 138, 139, 147, 148, 149 Seal material 141 Oxygen electrode side separator 151, 153, 163, 165 Flow path 154 Hydrogen pump

As a water electrolysis/fuel cell system using such a water electrolysis/fuel cell device, for example, the following can be proposed. That is, a power supply unit for supplying direct current power to the water electrolysis/fuel cell device, a raw water supply line for supplying raw material water to the water electrolysis/fuel cell device, and hydrogen gas generated in the water electrolysis/fuel cell device. to the outside of the system, an oxygen gas release path to release the oxygen gas generated in the water electrolysis/fuel cell device to the outside of the system, and hydrogen to supply hydrogen gas to the water electrolysis/fuel cell device a gas supply channel, a gas supply channel for supplying oxygen gas or air to the water electrolysis/fuel cell device, and an oxygen gas release channel for releasing water generated in the water electrolysis/fuel cell device outside the system. A water electrolysis/fuel cell system characterized by:

Note that the following configuration examples also belong to the technical scope of the present disclosure.
(1) A method of electrolyzing water using a water electrolysis apparatus in which a plurality of solid polymer water electrolysis cells are stacked, in which power feeders are arranged on both sides of an electrolyte membrane and separators are placed outside each power feeder. and
The solid polymer type water electrolysis cells are rectangular, and the water electrolysis cells are horizontally long and vertically arranged and horizontally stacked,
A water electrolysis method, characterized in that raw material water is supplied into the water electrolysis cell from the lower long side of the rectangular water electrolysis cell toward the upper long side of the water electrolysis cell.
(2) A water electrolysis device in which a plurality of solid polymer water electrolysis cells are stacked, each having power feeders arranged on both sides of an electrolyte membrane and a separator placed outside each power feeder,
The solid polymer type water electrolysis cells are rectangular, and the water electrolysis cells are horizontally long and vertically arranged and horizontally stacked,
A communication port for supplying water is disposed on the lower long side of each rectangular water electrolysis cell, and a communication port for discharging electrolyzed water and oxygen gas is disposed on the upper long side of each water electrolysis cell. is arranged, a water electrolysis device.
(3) The water electrolysis device according to (2), characterized in that a communication port for discharging hydrogen gas is arranged on the short side of each of the rectangular water electrolysis cells.
(4) Water electrolysis according to either (2) or (3), characterized in that the separator is formed with channels through which fluid can flow both in the vertical direction and in the horizontal direction. Device.
(5) A water electrolysis system using the water electrolysis device according to any one of (2) to (4),
a power supply device that supplies DC power to the water electrolysis device;
a raw water supply channel for supplying raw water to the water electrolysis device;
a hydrogen gas release path for releasing hydrogen gas generated in the water electrolysis device to the outside of the system;
an oxygen gas release path for releasing oxygen gas generated in the water electrolysis device to the outside of the system;
A water electrolysis system, comprising:
(6) Water in which a plurality of solid polymer type water electrolysis fuel cell integrated cells are stacked, in which power supply/current collectors are arranged on both sides of the electrolyte membrane, and separators are further arranged on the outside of each power supply/current collector. A method of switching between water electrolysis operation and fuel cell operation using an electrolysis/fuel cell device,
The solid polymer type water electrolysis fuel cell integrated cell is rectangular, and the water electrolysis fuel cell integrated cell is horizontally long and vertically arranged and stacked horizontally,
During the water electrolysis operation, raw water is supplied into the water electrolysis fuel cell integrated cell from the lower long side of the rectangular water electrolysis fuel cell integrated cell toward the upper long side of the water electrolysis fuel cell integrated cell,
During operation of the fuel cell, the raw material gas is supplied into the water electrolysis fuel cell integrated cell from the short side of the rectangular water electrolysis fuel cell integrated cell toward the opposite short side. a water electrolysis/fuel cell operation method.
(7) Water in which a plurality of solid polymer type water electrolysis fuel cell integrated cells are stacked, in which feeders and current collectors are arranged on both sides of the electrolyte membrane, and separators are further arranged on the outside of each of the feeders and collectors. An electrolysis/fuel cell device,
The solid polymer type water electrolysis fuel cell integrated cell is rectangular, and the water electrolysis fuel cell integrated cell is horizontally long and vertically arranged and stacked horizontally,
A communication port for supplying raw material water during water electrolysis operation and a communication port for supplying cooling water are arranged on the lower long side of each rectangular water electrolysis fuel cell integrated cell,
A communication port for discharging electrolyzed water and oxygen gas during water electrolysis operation is arranged on the upper long side of each water electrolysis fuel cell integrated cell,
On the short side of each water electrolysis fuel cell integrated cell, a communication port for discharging hydrogen gas during water electrolysis operation, a communication port for supplying hydrogen gas during fuel cell operation, and a communication port for supplying air or oxygen gas are provided. A water electrolysis/fuel cell device, characterized in that a communication port of is formed.
(8) The water electrolysis/fuel cell device according to (7), characterized in that the separator is formed with channels through which a fluid can flow both in the vertical direction and in the horizontal direction.
(9) A communication port through which air or oxygen gas and reaction product water are discharged is formed on the short side of the water electrolysis fuel cell integrated cell, and the water electrolysis fuel cell integrated cell , air or oxygen gas, and the water electrolysis system according to either one of (7) or (8), characterized in that the lowermost part of the communication port through which the water produced by the reaction is discharged is positioned downward. fuel cell device.
(10) A water electrolysis/fuel cell system using the water electrolysis/fuel cell device according to any one of (7) to (9),
a power supply device that supplies DC power to the water electrolysis/fuel cell device;
a raw water supply path for supplying raw water to the water electrolysis/fuel cell device;
a hydrogen gas release path for releasing hydrogen gas generated in the water electrolysis/fuel cell device to the outside of the system;
an oxygen gas release path for releasing oxygen gas generated in the water electrolysis/fuel cell device to the outside of the system;
a hydrogen gas supply path for supplying hydrogen gas to the water electrolysis/fuel cell device;
a gas supply path for supplying oxygen gas or air to the water electrolysis/fuel cell device;
and an oxygen gas discharge path for discharging water generated in the water electrolysis/fuel cell device to the outside of the system.

Claims (10)

A method of electrolyzing water using a water electrolysis device in which a plurality of solid polymer water electrolysis cells are stacked, in which power feeders are arranged on both sides of an electrolyte membrane and a separator is placed outside each power feeder. ,
The solid polymer type water electrolysis cells are rectangular, and the water electrolysis cells are horizontally long and vertically arranged and horizontally stacked,
A water electrolysis method, characterized in that raw material water is supplied into the water electrolysis cell from the lower long side of the rectangular water electrolysis cell toward the upper long side of the water electrolysis cell. A water electrolysis device in which a plurality of solid polymer type water electrolysis cells are stacked in which power feeders are arranged on both sides of an electrolyte membrane and separators are further placed outside each power feeder,
The solid polymer type water electrolysis cells are rectangular, and the water electrolysis cells are horizontally long and vertically arranged and horizontally stacked,
A communication port for supplying water is disposed on the lower long side of each rectangular water electrolysis cell, and a communication port for discharging electrolyzed water and oxygen gas is disposed on the upper long side of each water electrolysis cell. is arranged, a water electrolysis device. 3. The water electrolysis apparatus according to claim 2, wherein a communication port for discharging hydrogen gas is arranged on a short side of each of the rectangular water electrolysis cells. 4. The water electrolysis apparatus according to claim 2, wherein the separator is formed with flow paths through which fluid can flow both in the vertical direction and in the horizontal direction. A water electrolysis system using the water electrolysis device according to any one of claims 2 to 4,
a power supply device that supplies DC power to the water electrolysis device;
a raw water supply channel for supplying raw water to the water electrolysis device;
a hydrogen gas release path for releasing hydrogen gas generated in the water electrolysis device to the outside of the system;
an oxygen gas release path for releasing oxygen gas generated in the water electrolysis device to the outside of the system;
A water electrolysis system, comprising: Water electrolysis/fuel in which multiple solid polymer type water electrolysis fuel cell integrated cells are stacked, in which feeders/current collectors are arranged on both sides of the electrolyte membrane, and separators are further placed on the outside of each feeder/collector. A method of switching between water electrolysis operation and fuel cell operation using a battery device,
The solid polymer type water electrolysis fuel cell integrated cell is rectangular, and the water electrolysis fuel cell integrated cell is horizontally long and vertically arranged and stacked horizontally,
During the water electrolysis operation, raw water is supplied into the water electrolysis fuel cell integrated cell from the lower long side of the rectangular water electrolysis fuel cell integrated cell toward the upper long side of the water electrolysis fuel cell integrated cell,
During operation of the fuel cell, the raw material gas is supplied into the water electrolysis fuel cell integrated cell from the short side of the rectangular water electrolysis fuel cell integrated cell toward the opposite short side. a water electrolysis/fuel cell operation method. Water electrolysis/fuel in which multiple solid polymer type water electrolysis fuel cell integrated cells are stacked, in which feeders/current collectors are arranged on both sides of the electrolyte membrane, and separators are further placed on the outside of each feeder/collector. A battery device,
The solid polymer type water electrolysis fuel cell integrated cell is rectangular, and the water electrolysis fuel cell integrated cell is horizontally long and vertically arranged and stacked horizontally,
A communication port for supplying raw material water during water electrolysis operation and a communication port for supplying cooling water are arranged on the lower long side of each rectangular water electrolysis fuel cell integrated cell,
A communication port for discharging electrolyzed water and oxygen gas during water electrolysis operation is arranged on the upper long side of each water electrolysis fuel cell integrated cell,
On the short side of each water electrolysis fuel cell integrated cell, a communication port for discharging hydrogen gas during water electrolysis operation, a communication port for supplying hydrogen gas during fuel cell operation, and a communication port for supplying air or oxygen gas are provided. A water electrolysis/fuel cell device, characterized in that a communication port of is formed. 8. The water electrolysis/fuel cell device according to claim 7, wherein said separator has a flow path through which a fluid can flow both vertically and horizontally. On the short side of the water electrolysis fuel cell integrated cell, a communication port for discharging air or oxygen gas and reaction product water is formed, and the air or 9. The water electrolysis/fuel cell device according to claim 7, wherein the lowermost part of the communication port through which the oxygen gas and reaction product water are discharged is positioned downward. . A water electrolysis/fuel cell system using the water electrolysis/fuel cell device according to any one of claims 7 to 9,
a power supply device that supplies DC power to the water electrolysis/fuel cell device;
a raw water supply path for supplying raw water to the water electrolysis/fuel cell device;
a hydrogen gas release path for releasing hydrogen gas generated in the water electrolysis/fuel cell device to the outside of the system;
an oxygen gas release path for releasing oxygen gas generated in the water electrolysis/fuel cell device to the outside of the system;
a hydrogen gas supply path for supplying hydrogen gas to the water electrolysis/fuel cell device;
a gas supply path for supplying oxygen gas or air to the water electrolysis/fuel cell device;
and an oxygen gas discharge path for discharging water generated in the water electrolysis/fuel cell device to the outside of the system.

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