US20260028733A1

US20260028733A1 - Electrochemical apparatus

Info

Publication number: US20260028733A1
Application number: US19/277,788
Authority: US
Inventors: Satoki KABEYA; Takashi Kaneko; Shota Chatani
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2024-07-25
Filing date: 2025-07-23
Publication date: 2026-01-29

Abstract

An electrochemical apparatus includes a cell stack, a power conversion apparatus, a control unit, and a heating tank. The power conversion apparatus is electrically connected to the cell stack. The control unit controls the power conversion apparatus. The heating tank includes a housing space housing the cell stack and heats the cell stack. The cell stack produces hydrogen by electrolyzing water using supplied power, or generates power through an electrochemical reaction between hydrogen and an oxidizing agent. The power conversion apparatus is disposed outside the heating tank, further toward a lower side than the cell stack is. The power conversion apparatus and the cell stack are electrically connected by a conductor that passes through a wall portion of the heating tank. The power conversion apparatus is disposed such that at least a portion thereof overlaps the heating tank when viewed in a vertical direction.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priority from Japanese Patent Application No. 2024-119406, filed on Jul. 25, 2024. The entire disclosure of the above application is incorporated herein by reference.

BACKGROUND

Technical Field

The present disclosure relates to an electrochemical apparatus.

Related Art

A fuel cell system including a fuel cell stack, a control apparatus, and a power conversion apparatus is known. The fuel cell stack uses hydrogen as fuel. The control apparatus controls an amount of power generated by the fuel cell stack. The power conversion apparatus converts direct-current power generated by the fuel cell stack to power meeting required specifications.

SUMMARY

An aspect of the present disclosure provides an electrochemical apparatus that includes a cell stack, a power conversion apparatus, a control unit, and a heating tank. The cell stack is configured by a plurality of electrochemical cells being stacked. The power conversion apparatus is electrically connected to the cell stack. The control unit controls the power conversion apparatus. The heating tank includes a housing space housing the cell stack and heats the cell stack. The cell stack produces hydrogen by electrolyzing water using supplied power, or generates power through an electrochemical reaction between hydrogen and an oxidizing agent. The power conversion apparatus is disposed outside the heating tank, further toward a lower side than the cell stack is. The power conversion apparatus and the cell stack are electrically connected by a conductor that passes through a wall portion of the heating tank. The power conversion apparatus is disposed such that at least a portion thereof overlaps the heating tank when viewed in a vertical direction.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a perspective view of an electrochemical apparatus according to a first embodiment;

FIG. 2 is a configuration diagram of the electrochemical apparatus according to the first embodiment, taken along a vertical direction;

FIG. 3 is a diagram of the electrochemical apparatus according to the first embodiment, viewed from above;

FIG. 4 is a cross-sectional view of an electrochemical cell according to the first embodiment;

FIG. 5 is a configuration diagram of an electrochemical apparatus according to a second embodiment, taken along the vertical direction;

FIG. 6 is a configuration diagram of an electrochemical apparatus according to a third embodiment, taken along the vertical direction; and

FIG. 7 is a configuration diagram of an electrochemical apparatus according to a fourth embodiment, taken along the vertical direction.

DESCRIPTION OF THE EMBODIMENTS

For example, as disclosed in JP 2011-228180 A, a fuel cell system including a fuel cell stack, a control apparatus, and a power conversion apparatus. The fuel cell stack uses hydrogen as fuel. The control apparatus controls an amount of power generated by the fuel cell stack. The power conversion apparatus converts direct-current power generated by the fuel cell stack to power meeting required specifications. In the fuel cell system described in JP 2011-228180 A, the fuel cell stack, the control apparatus, and the power conversion apparatus are housed in a casing. In addition, the casing includes an opening/closing door that freely opens and closes in relation to a casing main body portion. The power conversion apparatus and the control apparatus are mounted to the opening/closing door. As a result, maintenance of the power conversion apparatus and the like inside the casing can be facilitated through a simple and compact configuration.
However, in the fuel cell system described in JP 2011-228180 A, the power conversion apparatus is disposed in a position away from the fuel cell stack. Therefore, wiring that electrically connects the power conversion apparatus and the fuel cell stack tends to become long. Consequently, in addition to an increase in power loss, size also tends to increase. Furthermore, in the fuel cell system described in JP 2011-228180 A, the power conversion apparatus is disposed in an upper portion of the casing. Therefore, it can be said that there is room for improvement from the perspective of ensuring safety against leakage of hydrogen gas.
It thus desired to provide an electrochemical apparatus that is capable of achieving size reduction and enhanced power efficiency, as well as improved safety.
An exemplary embodiment of the present disclosure is an electrochemical apparatus including: a cell stack configured by a plurality of electrochemical cells being stacked; a power conversion apparatus that is electrically connected to the cell stack; a control unit that controls the power conversion apparatus; and a heating tank that includes a housing space housing the cell stack and heats the cell stack. The cell stack is configured to produce hydrogen by electrolyzing water using supplied power, or generate power through an electrochemical reaction between hydrogen and an oxidizing agent. The power conversion apparatus is disposed outside the heating tank, further toward a lower side than the cell stack is. The power conversion apparatus and the cell stack are electrically connected by a conductor that passes through a wall portion of the heating tank. The power conversion apparatus is disposed such that at least a portion thereof overlaps the heating tank when viewed in a vertical direction.
In the above-described electrochemical apparatus, the power conversion apparatus is disposed such that at least a portion thereof overlaps the heating tank when viewed in the vertical direction. Therefore, a length of the conductor electrically connecting the power conversion apparatus and the cell stack can be easily shortened. Consequently, size reduction of the electrochemical apparatus can be achieved and enhanced power efficiency can be achieved.
In addition, in the above-described electrochemical apparatus, the power conversion apparatus is disposed outside the heating tank, further toward the lower side than the cell stack is. Therefore, even in a rare case of hydrogen gas leaking from the cell stack, the power conversion apparatus is unlikely to become an ignition source. Consequently, improved safety can be achieved.
As described above, according to the above-described exemplary embodiment, an electrochemical apparatus that is capable of achieving size reduction and enhanced power efficiency, as well as improved safety, can be provided.

First Embodiment

An electrochemical apparatus according to a first embodiment will be described with reference to FIG. 1 to FIG. 4 .
As shown in FIG. 1 and FIG. 2 , an electrochemical apparatus 1 according to the present embodiment includes a cell stack 2, a power conversion apparatus 3, a control unit 4, and a heating tank 5. As shown in FIG. 2 , the cell stack 2 is configured by a plurality of electrochemical cells 20 being stacked. The power conversion apparatus 3 is electrically connected to the cell stack 2. The control unit 4 controls the power conversion apparatus 3. The heating tank 5 includes a housing space 50 housing the cell stack 2 and heats the cell stack 2.
The cell stack 2 is configured to produce hydrogen by electrolyzing water using supplied power, or generate power through an electrochemical reaction between hydrogen and an oxidizing agent.
The power conversion apparatus 3 is disposed outside the heating tank 5, further toward a lower side Z1 than the cell stack 2 is. The power conversion apparatus 3 and the cell stack 2 are electrically connected by a conductor 11 that passes through a wall portion 51 of the heating tank 5. As shown in FIG. 3 , the power conversion apparatus 3 is disposed such that at least a portion thereof overlaps the heating tank 5 when viewed in a vertical direction Z.
For example, the electrochemical apparatus 1 can be used as a fuel cell that generates power using a reaction between hydrogen and oxygen that serves as the oxidizing agent, or a hydrogen production apparatus that produces hydrogen by electrolyzing steam using supplied power. The electrochemical apparatus 1 according to the present embodiment is the hydrogen production apparatus that produces hydrogen. According to the present embodiment, the cell stack 2 produces hydrogen by electrolyzing water that serves as a raw material using power supplied from a power source 10 (see FIG. 2 ), through the power conversion apparatus 3.
In the cell stack 2, electrochemical cells 20 are electrically connected to each other in series. According to the present embodiment, the electrochemical cell 20 configuring the cell stack 2 is a solid oxide electrolysis cell (SOEC). As shown in FIG. 4 , the electrochemical cell 20 includes an air electrode 202 and a hydrogen electrode 201, and further includes an electrolyte 203 interposed between the hydrogen electrode 201 and the air electrode 202.
According to the present embodiment, the hydrogen electrode 201 is supplied a gas containing steam and the air electrode 202 is supplied air. That is, water to be electrolyzed is supplied to the hydrogen electrode 201 in a steam state. In addition, the electrolyte 203 is composed of a solid oxide ceramic and has oxide ion (O²⁻) conductivity. For example, the electrolyte 203 can be composed of yttria-stabilized zirconia, perovskite-type oxide, or the like.
The steam supplied to the electrochemical cell 20 undergoes an electrolytic reaction of H₂O+2e⁻→H₂+O²⁻ at the hydrogen electrode 201 and O²⁻→½O₂+2e⁻ at the air electrode 202. That is, at the hydrogen electrode 201, the steam is electrolyzed and hydrogen gas and oxide ions (O²⁻) are produced. The oxide ions move through the electrolyte 203 to the air electrode 202 side, and then are oxidized at the air electrode 202 and become oxygen gas. The gas containing hydrogen produced as a result of the electrolysis reaction is discharged outside the electrochemical cell 20 from the hydrogen electrode 201. The gas containing oxygen that is also generated is discharged outside the electrochemical cell 20 as well, from the air electrode 202.
In addition, according to the present embodiment, the power conversion apparatus 3 supplies power to the cell stack 2. Specifically, the power conversion apparatus 3 converts alternating-current power from the power supply 10 shown in FIG. 2 to direct-current power and supplies the direct-current power to the cell stack 2.
As shown in FIG. 3 , the power conversion apparatus 3 is disposed such that at least half of a projection area projected in the vertical direction Z overlaps the heating tank 5 when viewed in the vertical direction Z. In addition, the power conversion apparatus 3 is disposed such as to overlap the heating tank 5 in its entirety when viewed in the vertical direction Z. Furthermore, the power conversion apparatus 3 is disposed such that at least a portion overlaps the cell stack 2 when viewed in the vertical direction Z. Moreover, the power conversion apparatus 3 is disposed such that half or more of the projection area projected in the vertical direction Z overlaps the cell stack 2 when viewed in the vertical direction Z. The vertical direction Z is a direction along a vertical direction.
Of the power conversion apparatus 3 and the cell stack 2, the one which has a smaller projection area projected in the vertical direction Z is a small area portion 18 and the one which has a larger projection area projected in the vertical direction Z is a large area portion 19. According to the present embodiment, the small area portion 18 is disposed such that half or more of the projection area projected in the vertical direction Z overlaps the large area portion 19 when viewed in the vertical direction Z. In addition, the large area portion 19 is disposed such that half or more of the projection area projected in the vertical direction Z overlaps the small area portion 18 when viewed in the vertical direction Z. According to the present embodiment, the small area portion 18 is disposed such as to overlap the large area portion 19 in its entirety, when viewed in the vertical direction Z. Here, according to the present embodiment, the small area portion 18 is the power conversion apparatus 3 and the large area portion 19 is the cell stack 2.
The electrochemical apparatus 1 according to the present embodiment includes a plurality of cell stacks 2 and a plurality of power conversion apparatuses 3. Each of the plurality of cell stacks 2 is connected to a differing power conversion apparatus 3. The cell stack 2 and the power conversion apparatus 3 that are electrically connected to each other are disposed such that at least portions thereof overlap each other when viewed in the vertical direction Z. According to the present embodiment, of the small area portion 18 and the large area portion 18 that are electrically connected to each other, the small area portion 18 is disposed such that half or more of the projection area projected in the vertical direction Z overlaps the large area portion 19 when viewed in the vertical direction Z. In addition, of the small area portion 18 and the large area portion 18 that are electrically connected to each other, the large area portion 19 is disposed such that half or more of the projection area projected in the vertical direction Z overlaps the small area portion 18 when viewed in the vertical direction Z. According to the present embodiment, of the small area portion 18 and the large area portion 18 that are electrically connected to each other, the small area portion 18 is disposed such as to overlap the large area portion 18 in its entirety when viewed in the vertical direction Z. According to the present embodiment, the number of cell stacks 2 and the number of power conversion apparatuses 3 are the same.
In addition, the wall portion 51 of the heating tank 5 is covered by a thermal insulation material (not shown) on a side facing the housing space 50. That is, the cell stacks 2 are housed in the housing space 50 covered by the thermal insulation material. The heating tank 5 heats and warms the cell stacks 2 to a temperature suitable for electrolysis of water.
As shown in FIG. 2 , the heating tank 5 includes a cell heating unit 52 for heating the cell stacks 2 inside the housing space 50. For example, the cell heating unit 52 can be an electric heater, a burner, or a heat exchanger. The control unit 4 adjusts a temperature of the cell stacks 2 to a range of 550° C. to 850° C., for example, by controlling the cell heating unit 52.
An apparatus housing chamber 53 housing the power conversion apparatuses 3 is provided on the lower side Z1 of a bottom wall 511 of the heating tank 5. In addition to the power conversion apparatuses 3, the control unit 4 is disposed in an internal space 530 that is a space inside the apparatus housing chamber 53. Furthermore, a wall portion covering an upper side Z2 of the internal space 530 is also the bottom wall 511 of the heating tank 5.
As shown in FIG. 1 and FIG. 2 , the cell stack 2 and the power conversion apparatus 3 are directly connected by a bus bar that serves as the conductor 11. As shown in FIG. 2 , the cell stack 2 and the power conversion apparatus 3 oppose each other in the vertical direction Z with the bottom wall 511 of the heating tank 5 provided with the heat insulation material therebetween. That is, the cell stack 2 and the power conversion apparatus 3 are provided such as to sandwich the bottom wall 551 in the vertical direction Z. In addition, the bus bar 11 passes through the bottom wall 511 of the heating tank 5.
The control unit 4 is disposed further toward the lower side Z1 than the power conversion apparatus 3 is. According to the present embodiment, the control unit 4 adjusts power supplied to the cell stack 2 by controlling the power conversion apparatus 3. The control unit 4 includes a processor and a memory.
In addition, the electrochemical apparatus 1 according to the present embodiment includes a ventilating unit 6. The ventilating unit 6 ventilates the housing space 50 by supplying air into the housing space 50 from outside the heating tank 5.
According to the present embodiment, the ventilating unit 6 is provided near the bottom wall 511 in the wall portion 51 of the heating tank 5. For example, the ventilating unit 6 can be an air-blowing fan.
A ventilation hole 510 communicating between the housing space 50 and the outside is formed in a ceiling portion 512 of the wall portion 51 of the heating tank 5. The air supplied to the housing space 50 by the ventilating unit 6 is discharged outside the housing space 50 through the ventilation hole 510. In the heating tank 5, the ventilation hole 510 is formed in a position away from the ventilating unit 6. As shown in FIG. 3 , the ventilation hole 510 and the ventilating unit 6 are positioned on diagonally opposing corners of the heating tank 5 when viewed in the vertical direction Z.
In addition, as shown in FIG. 2 , the electrochemical apparatus 1 includes a discharge flow path 22 through which gas discharged from the cell stack 2 flows. The discharge flow path 22 passes through the wall portion 51 of the heating tank 5 and extends outside the heating tank 5 from the cell stack 2.
Furthermore, the electrochemical apparatus 1 includes a discharge flow path heat exchanger 71. The discharge flow path heat exchanger 71 is disposed in the housing space 50 and cools the gas flowing through the discharge flow path 22.
According to the present embodiment, the electrochemical apparatus 1 includes a hydrogen-electrode discharge flow path 221 and an air-electrode discharge flow path 222 as the discharge flow path 22. The hydrogen-electrode discharge flow path 221 is connected to the cell stack 2 and is a flow path through which the gas discharged from the hydrogen electrode 201 flows. The air-electrode discharge flow path 222 is connected to the cell stack 2 and is a flow path through which the gas discharged from the air electrode 202 flows. According to the present embodiment, the gas containing hydrogen produced by the cell stack 2 flows through the hydrogen-electrode discharge flow path 221 and the gas containing oxygen produced by the cell stack 2 flows through the air-electrode discharge flow path 222.
According to the present embodiment, the hydrogen-electrode discharge flow path 221 and the air-electrode discharge flow path 222 are both connected to the discharge flow path heat exchanger 71. The gas discharged from the hydrogen electrode 201 passes through the discharge flow path heat exchanger 71 through the hydrogen-electrode discharge flow path 221 and is then guided outside the heating tank 5 from the housing space 50 through the hydrogen-electrode discharge flow path 221. The gas discharged from the air electrode 202 passes through the discharge flow path heat exchanger 71 through the air-electrode discharge flow path 222, and is then guided outside the heating tank 5 from the housing space 50 through the air-electrode discharge flow path 222.
In addition, the electrochemical apparatus 1 according to the present embodiment includes a steam supply flow path 211 that supplies gas containing steam to the hydrogen electrode 201 of the electrochemical cell 20 and an air supply flow path 212 that supplies air to the air electrode 202. The steam supply flow path 211 and the air supply flow path 212 both pass through the wall portion 51 of the heating tank 5 and extend to the cell stack 2 inside the housing space 50 from outside the heating tank 5. In addition, the steam supply flow path 211 and the air supply flow path 212 are both connected to the discharge flow path heat exchanger 71. According to the present embodiment, the gas containing steam and the air are supplied to the cell stack 2 after temperatures thereof are raised by passing through the discharge flow path heat exchanger 71 through the steam supply flow path 211 or the air supply flow path 212. That is, the gas flowing through the steam supply flow path 211 and the gas flowing through the air supply flow path 212 both rise in temperature as a result of heat being exchanged with the gas flowing through the discharge flow path 22 in the discharge flow path heat exchanger 71.
For example, the discharge flow path heat exchanger 71 can be a heat exchanger group that includes a plurality of heat exchangers. In this case, for example, the discharge flow path heat exchanger 71 can include a heat exchanger that exchanges heat between the gas flowing through the steam supply flow path 211 and the gas flowing through the hydrogen-electrode discharge flow path 221, and a heat exchanger that exchanges heat between the gas flowing through the steam supply flow path 211 and the gas flowing through the air-electrode discharge flow path 222. In addition, for example, the discharge flow path heat exchanger 71 can include a heat exchanger that exchanges heat between the gas flowing through the air supply flow path 212 and the gas flowing through the hydrogen-electrode discharge flow path 221, and a heat exchanger that exchanges heat between the gas flowing through the air supply flow path 212 and the gas flowing through the air-electrode discharge flow path 222.
Furthermore, outside the heating tank 5, an evaporator 13 is provided on the steam supply flow path 211. The evaporator 13 produces steam by evaporating liquid water. The steam produced by the evaporator 13 is supplied to the hydrogen electrode 201 through the steam supply flow path 211. For example, a temperature of the steam produced by the evaporator 13 can be about 150° C. In addition, for example, the evaporator 13 can include a heater or a heat pump for heating the liquid water.
The electrochemical apparatus 1 includes a water supply flow path 214 that is connected to the evaporator 13 and supplies water to the evaporator 13. The water supply flow path 214 is provided with a water pump 14 and a water purifier 15. The water pump 14 supplies water to the evaporator 13 through the water purifier 15. The water purifier 15 removes particulate matter, ions, and the like contained in the water supplied from the water pump 14, thereby purifying the water supplied from the water pump 14 to pure water. For example, the water purifier 15 can be an apparatus including a reverse osmosis membrane or an ion exchange resin.
In addition, outside the heating tank 5, an air pump 12 is provided on the air supply flow path 212. The air pump 12 supplies air to the air electrode 202 in a pressurized state.
Furthermore, outside the heating tank 5, an external heat exchanger 72 is provided on the hydrogen-electrode discharge flow path 221. The external heat exchanger 72 is configured such that cooling water is introduced. For example, the external heat exchanger 72 can cool the gas flowing through the hydrogen-electrode discharge flow path 221 from about 500° C. to about 10° C.
Next, working effects according to the present embodiment will be described.
In the above-described electrochemical apparatus 1, the power conversion apparatus 3 is disposed such that at least a portion thereof overlaps the heating tank 5 when viewed in the vertical direction Z. Therefore, a length of the conductor 11 electrically connecting the power conversion apparatus 3 and the cell stack 2 can be easily shortened. Consequently, size reduction of the electrochemical apparatus 1 can be achieved and enhanced power efficiency can be achieved.
In addition, in the above-described electrochemical apparatus 1, the power conversion apparatus 3 is disposed outside the heating tank 5, further toward the lower side Z1 than the cell stack 2 is. Therefore, even in a rare case of hydrogen gas leaking from the cell stack 2, the power conversion apparatus 3 is unlikely to become an ignition source. Consequently, improved safety can be achieved.
That is, space required to set up the conductor 11 can be reduced to the extent that the length of the conductor 11 is shortened. Size reduction of the electrochemical apparatus 1 can be achieved. In addition, as the length of the conductor 11 becomes shorter, loss of power supplied to the cell stack 2 from the power conversion apparatus 3 tends to decrease. Enhanced power efficiency can be achieved. Furthermore, because hydrogen is lighter than air, hydrogen tends to move toward the upper side Z2. Therefore, as a result of the power conversion apparatus 3 being disposed further toward the lower side Z1 than the cell stack 2 is, even in the rare case of hydrogen leaking from the cell stack 2, the power conversion apparatus 3 can be prevented from becoming an ignition source. Consequently, improved safety can be achieved.
The power conversion apparatus 3 is disposed such that at least a portion thereof overlaps the cell stack 2 when viewed in the vertical direction Z. Therefore, the length of the conductor 11 can be more easily shortened. Consequently, size reduction of the electrochemical apparatus 1 can be further achieved and enhanced power efficiency can be further achieved.
In addition, the cell stack 2 and the power conversion apparatus 3 are provided such as to sandwich the bottom wall 511 of the heating tank 5 in the vertical direction Z. Therefore, the length of the conductor 11 in the vertical direction X can be further shortened. Consequently, size reduction of the electrochemical apparatus 1 can be further achieved and enhanced power efficiency can be further achieved.
The electrochemical apparatus 1 according to the present embodiment includes a plurality of cell stacks 2 and a plurality of power conversion apparatuses 3. Each of the plurality of cell stacks 2 is electrically connected to respective power conversion apparatuses 3. Therefore, power can be individually supplied to the cell stacks 2 from the power conversion apparatuses 3, to accommodate each cell stack 2. Thus, power supply can be performed based on a state of degradation and the like of the cell stack 2. Consequently, increased lifespan of each cell stack 2 can be achieved. In addition, the cell stack 2 and the power conversion apparatus 3 that are electrically connected to each other are disposed such that at least portions thereof overlap each other when viewed in the vertical direction Z. Consequently, size reduction of the electrochemical apparatus 1 and enhanced power efficiency can be further achieved.
The electrochemical apparatus 1 according to the present embodiment includes the ventilating unit 6. Therefore, even in the rare case of gas containing hydrogen leaking from the cell stack 2, the hydrogen can be efficiently discharged outside from the housing space 50. Consequently, safety can be further improved.
The control unit 4 is disposed further toward the lower side Z1 than the power conversion apparatus 3 is. Therefore, even in the rare case of water leakage in the electrochemical apparatus 1 or water exposure of the electrochemical apparatus 1, operation of the overall electrochemical apparatus 1 can be stopped by the control unit 4 stopping first. Consequently, safety can be further improved.
According to the present embodiment, the cell stack 2 and the power conversion apparatus 3 are directly connected by the bus bar 11. Consequently, size reduction of the electrochemical apparatus 1 can be sufficiently achieved and enhanced power efficiency can be sufficiently achieved.
As described above, according to the present embodiment, the electrochemical apparatus 1 capable of achieving size reduction and enhanced power efficiency, as well as improved safety, can be provided.
According to the above-described first embodiment, the air electrode 202 is supplied air. However, for example, the electrochemical apparatus can be configured such that the air electrode 202 is supplied gas that has a lower oxygen partial pressure than air.

Second Embodiment

According to a second embodiment, a ventilation means for the housing space 50 differs from that according to the first embodiment.
The electrochemical apparatus 1 according to the present embodiment is configured to ventilate the housing space 50 by supplying the gas discharged from the air electrode 202 (see FIG. 4 according to the first embodiment) into the housing space 50.
As shown in FIG. 5 , the electrochemical apparatus 1 according to the present embodiment includes an in-space discharge flow path 23 through which the gas discharged from the air electrode 202 flows and in which a discharge opening 231 for gas is disposed inside the housing space 50. The in-space discharge flow path 23 is connected to the cell stack 2. According to the present embodiment, the gas discharged from the air electrode 202 is supplied into the housing space 50 from the discharge opening 231 after passing through the in-space discharge flow path 23.
Other configurations are similar to those according to the first embodiment. Here, of reference numbers used according to second and subsequent embodiments, reference numbers that are the same as those used in preceding embodiments indicate similar constituent elements as those according to the preceding embodiments unless otherwise specified.
The electrochemical apparatus 1 according to the present embodiment is configured to ventilate the housing space 50 by supplying the gas discharged from the air electrode 202 into the housing space 50. Therefore, even in the rare case of gas containing hydrogen leaking from the cell stack 2, the hydrogen can be efficiently discharged outside from the housing space 50. Consequently, safety can be further improved. In addition, because discharged gas from the air electrode 202 is used for ventilation, the housing space 50 can be ventilated without a new apparatus or the like being provided. Consequently, size reduction of the electrochemical apparatus 1 can be further achieved while further improving safety.
Other working effects are similar to those according to the first embodiment.

Third Embodiment

As shown in FIG. 6 , according to a third embodiment, the configuration of the water supply flow path 214 differs from that according to the first embodiment.
According to the present embodiment, the power conversion apparatus 3 is configured to be cooled by cooling water. The configuration is such that the cooling water flows into the discharge flow path heat exchanger 71 after cooling the power conversion apparatus 3, thereby cooling the gas flowing through the discharge flow path 22.
According to the present embodiment, the water supply flow path 214 extending from the water purifier 15 passes through a wall portion of the apparatus housing chamber 53 and is connected to the power conversion apparatus 3 dispose inside the internal space 530. Inside the internal space 530, the water supply flow path 214 branches out and connects to each power conversion apparatus 3. That is, the water that passes through the water purifier 15 is supplied to each power conversion apparatus 3 as cooling water. The cooling water supplied to each power conversion apparatus 3 merges after passing through the power conversion apparatuses 3. The water supply flow path 214 through which the merged cooling water flows passes through the bottom wall 511, extends to the housing space 50 from the internal space 530, and is connected to the discharge flow path heat exchanger 71. That is, the cooling water that has cooled the power conversion apparatus 3 passes through the discharge flow path heat exchanger 71 through the water supply flow path 214 and is then supplied to the evaporator 13 through the water supply flow path 214.
Here, when a temperature of the cooling water introduced to the power conversion apparatus 3 is about 30° C., the temperature of the cooling water discharged from the power conversion apparatus 3 is about 40° C., for example. The cooling water that is about 40° C. is then introduced to the discharge flow path heat exchanger 71. Heat is exchange between the cooling water and the gas discharged from the cell stack 2, and the cooling water becomes about 80° C., for example, and is discharged from the discharge flow path heat exchanger 71. Then, the cooling water that is about 80° C. is introduced into the evaporator 13 and becomes steam as result of being heated. The steam produced from the cooling water is again introduced into the discharge flow path heat exchanger 71. Heat is exchanged with the gas discharged from the cell stack 2, and the cooling water is then introduced to the cell stack 2 after the temperature rises.
Furthermore, the gas discharged from the hydrogen electrode 201 is introduced to the discharge flow path heat exchanger 71 through the hydrogen-electrode discharge flow path 221. The gas discharged from the hydrogen electrode 201 exchanges heat with the cooling water from the power conversion apparatus 3, the steam from the evaporator 13, and the like in the discharge flow path heat exchanger 71, and is thereby cooled from about 700° C. to about 500° C. Subsequently, the gas discharged from the hydrogen electrode 201 is cooled to about 10° C., for example, by the external heat exchanger 72.
The gas discharged from the air electrode 202 is also cooled from about 700° C. to about 500° C., for example, by heat exchange with the cooling water from the power conversion apparatus 3 and the like in the discharge flow path heat exchanger 71, in a manner similar to the gas discharged from the hydrogen electrode 201. Subsequently, the gas discharged from the air electrode 202 is discharged outside the heating tank 5 through the air-electrode discharge flow path 222.
In the case in which the discharge flow path heat exchanger 71 is a heat exchanger group, for example, the discharge flow path heat exchanger 71 can include a heat exchanger that exchanges heat between the water flowing through the water supply flow path 214 and the gas flowing through the hydrogen-electrode discharge flow path 221, a heat exchanger that exchanges heat between the water flowing through the water supply flow path 214 and the gas flowing through the air-electrode discharge flow path 222, and the like.
In addition, according to the present embodiment, a branching flow path 215 that branches from the water supply flow path 214 connecting the power conversion apparatus 3 and the discharge flow path heat exchanger 71 is included. The branching flow path 215 passes through the wall portion 51 of the heating tank 5 and extends outside the housing space 50 from the water supply flow path 214.
Furthermore, the electrochemical apparatus 1 includes a temperature measuring unit 216 that measures the temperature of the water flowing through the branching flow path 215. In addition, the branching flow path 215 is provided with a flow amount adjusting unit (not shown) for adjusting an amount of water supplied to the branching flow path 215 from the water supply flow path 214. For example, the flow amount adjusting unit provided in the branching flow path 215 is an electromagnetic valve or the like.
In the electrochemical apparatus 1 according to the present embodiment, a cooling water heat exchanger 17 that enables heat exchange between the water flowing through the branching flow path 215 and the water supply flow path 214 is provided near the water pump 14 on the water supply flow path 214. In addition, the evaporator 13 includes a heat pump (not shown) and is configured to use the water from the branching flow path 215 as a heat source of the heat pump. That is, the branching flow path 215 branches out (not shown) and is connected to the cooling water heat exchanger 17 and the evaporator 13 outside the heating tank 5. Furthermore, the flow amount adjusting unit for adjusting an amount of water flow is also provided in the branching flow path 215 connected to the cooling water heat exchanger 17 or the heat pump.
The electrochemical apparatus 1 according to the present embodiment is configured such that the flow amount of water flowing through the branching flow path 215 is adjusted by the control unit 4. The control unit 4 calculates the amount of water to be supplied to the cooling water heat exchanger 17 or the heat pump based on information such as an amount of heat required by the cooling water heat exchanger 17 or the heat pump of the evaporator 13. Then, by controlling the flow amount adjusting unit provided on the branching flow path 215 based on the calculation result, the control unit 4 adjusts the amount of water supplied to the cooling water heat exchanger 17 and the heat pump. That is, the control unit 4 adjusts the amount of water to be supplied upon setting an order of priority between the cooling water heat exchanger 17 and the evaporator 13.
Other configurations are similar to those according to the first embodiment.
According to the present embodiment, the power conversion apparatus 3 is configured to be cooled by the cooling water. The cooling water is configured to cool the gas flowing through the discharge flow path 22 by flowing into the discharge flow path heat exchanger 71 after cooling the power conversion apparatus 3. As a result, the cooling water can efficiently cool the gas flowing through the power conversion apparatus 3 and the discharge flow path 22. Consequently, energy efficiency of the electrochemical apparatus 1 can be improved.
The electrochemical apparatus 1 according to the present embodiment includes the branching flow path 215 branching from the water supply flow path 214. Therefore, waste heat discharged from the power conversion apparatus 3 can be effectively used. That is, the water heated by the power conversion apparatus 3 can be supplied to the cooling water heat exchanger 17 or the heat pump of the evaporator 13 through the branching flow path 215. As a result, the waste heat from the power conversion apparatus 3 can be used to suppress freezing of the water supply flow path 214 by the cooling water heat exchanger 17 or as a heat source for the heat pump. Consequently, energy efficiency of the electrochemical apparatus 1 and reliability of driving can be improved.
In addition, according to the present embodiment, the configuration is such that the water introduced to both the power conversion apparatus 3 and the discharge flow path heat exchanger 71 is supplied to the evaporator 13. Therefore, the water of which the temperature has been raised by heat released from both the power conversion apparatus 3 and the discharge flow path 22 can be supplied to the evaporator 13. Consequently, energy efficiency can be further improved.
The electrochemical apparatus 1 is configured to adjust the amount of water flowing through the branching flow path 215 by the control unit 4. Therefore, the water flowing through the branching flow path 215 can be supplied to each component based on the amount of heat required by the cooling water heat exchanger 17, the evaporator 13, and the like. Consequently, energy efficiency can be further improved.
Other working effects are similar to those according to the first embodiment.
According to the third embodiment, the branching flow path 215 branches out from the water supply flow path 214 connecting the power conversion apparatus 3 and the discharge flow path heat exchanger 71. However, for example, the branching flow path can branch out from a water supply flow path connecting the discharge flow path heat exchanger and the evaporator.
In addition, for example, the water flowing through the branching flow path 215 can also be used as the cooling water flowing through the external heat exchanger 72 or can be used to prevent freezing of the air supply flow path 212. Furthermore, for example, the water flowing through the branching flow path 215 can be used as a heat source for a proton exchange membrane (PEM) water electrolyzer or an ammonia synthesizer.

Fourth Embodiment

According to a fourth embodiment, the cell stack 2 functions as a fuel cell. That is, the cell stack 2 is configured to generate power through an electrochemical reaction between hydrogen and an oxidizing agent.
According to the present embodiment, the electrochemical cell 20 of the cell stack 2 is a solid oxide fuel cell (SOFC). In the cell stack 2, air containing oxygen that serves as the oxidizing agent is supplied to the air electrode 202 (see FIG. 4 according to the first embodiment) of the electrochemical cell 20 and gas containing hydrogen is supplied to the hydrogen electrode 201 (see FIG. 4 according to the first embodiment) of the electrochemical cell 20.
As shown in FIG. 7 , the electrochemical apparatus 1 according to the present embodiment includes a hydrogen supply flow path 213 that supplies the gas containing hydrogen to the hydrogen electrode 201 of the cell stack 2. In addition, the air supply flow path 212 supplies air to the air electrode 202 of the cell stack 2.
The electrochemical apparatus 1 according to the present embodiment includes a hydrogen supplying unit 16 that supplies fuel gas containing hydrogen to the hydrogen supply flow path 213. The hydrogen supply unit 16 is connected to the hydrogen supply flow path 213. For example, the hydrogen supplying unit 16 can be a reformer. The reformer produces gas containing hydrogen by reforming methane gas or city gas of which the main component is methane through catalytic reaction. In addition, for example, the hydrogen supply unit 16 can also be a storage tank that stores hydrogen gas.
In the case in which the discharge flow path heat exchanger 71 is a heat exchanger group, for example, the discharge flow path heat exchanger 71 can include a heat exchanger that exchanges heat between the gas flowing through the hydrogen supply flow path 213 and the gas flowing through the hydrogen-electrode discharge flow path 221, a heat exchanger that exchanges heat between the gas flowing through the hydrogen supply flow path 213 and the gas flowing through the air-electrode discharge flow path 222, and the like.
Next, reactions during power generation in the cell stack 2 will be described.
According to the present embodiment, oxide ions are produced by oxygen being reduced at the air electrode of the electrochemical cell 20. In addition, a reaction in which protons and electrons are produced from the hydrogen in the fuel occurs at the hydrogen electrode. The produced electrons flow to the power conversion apparatus 3. The protons react with the oxide ions that have moved to the hydrogen electrode side through the electrolyte, and steam is produced. The steam produced at the hydrogen electrode is discharged to the hydrogen-electrode discharge flow path 221. The air after oxygen is consumed at the air electrode is discharged to the air-electrode discharge flow path 222.
Furthermore, the power conversion apparatus 3 is electrically connected to an external load (not shown). According to the present embodiment, the power conversion apparatus 3 converts output power from the cell stack 2. Specifically, the power conversion apparatus 3 converts direct-current power that is the output power from the cell stack 2 to alternating-current power or converts a magnitude of voltage.
Other configurations are similar to those according to the first embodiment.
According to the present embodiment as well, the power conversion apparatus 3 is disposed such that at least a portion thereof overlaps the heating tank 5 when viewed in the vertical direction Z. Therefore, the length of the conductor 11 can be easily shortened. Consequently, size reduction of the power conversion apparatus 1 can be achieved and enhanced power efficiency can be achieved. Furthermore, because the power conversion apparatus 3 is disposed further toward the lower side Z1 than the cell stack 2 is, even in the rare case of hydrogen leaking from the cell stack 2, the power conversion apparatus 3 is unlikely to become an ignition source.
Other working effects are similar to those according to the first embodiment.
According to the above-described fourth embodiment, air is supplied to the air electrode. However, for example, the electrochemical apparatus can also be configured such that gas that has a higher oxygen partial pressure than air is supplied to the air electrode.
According to the above-described first to fourth embodiments, the cell stack 2 and the power conversion apparatus 3 are directly connected by the bus bar 11. However, for example, the cells stack 2 and the power conversion apparatus 3 can also be electrically connected to each other by a bus bar connected to the cell stack 2 and a bus bar connected to the power conversion apparatus 3 being connected to each other by a member having conductivity.
According to the above described first to fourth embodiments, the electrochemical apparatus 1 includes a plurality of cell stacks 2 and a plurality of power conversion apparatuses 3. However, the electrochemical apparatus 1 can also be configured to include a single cell stack 2 and a single power conversion apparatus 3. In addition, the electrochemical apparatus 2 can be configured to include two cell stacks 2 and two power conversion apparatuses 3. Alternatively, the electrochemical apparatus can be configured to include three or more cell stacks 2 and three or more power conversion apparatuses 3.
The present disclosure is not limited to the above-described embodiments. Various embodiments are applicable without departing from the spirit of the invention.

<Other>

Characteristics of the present disclosure are as follows:

[Aspect 1]

An electrochemical apparatus (1), including: a cell stack (2) configured by a plurality of electrochemical cells (20) being stacked; a power conversion apparatus (3) that is electrically connected to the cell stack; a control unit (4) that controls the power conversion apparatus; and a heating tank (5) that includes a housing space (50) housing the cell stack and heats the cell stack, in which the cell stack is configured to produce hydrogen by electrolyzing water using supplied power, or generate power through an electrochemical reaction between hydrogen and an oxidizing agent, the power conversion apparatus is disposed outside the heating tank, further toward a lower side (Z1) than the cell stack is, the power conversion apparatus and the cell stack are electrically connected by a conductor (11) that passes through a wall portion (51) of the heating tank, and the power conversion apparatus is disposed such that at least a portion thereof overlaps the heating tank when viewed in a vertical direction (Z).

[Aspect 2]

The electrochemical apparatus according to aspect 1, in which: the power conversion apparatus is disposed such that at least a portion thereof overlaps the cell stack when viewed in the vertical direction.

[Aspect 3]

The electrochemical apparatus according to aspect 2, including: a plurality of cell stacks and a plurality of power conversion apparatuses, in which the plurality of cell stacks are each electrically connected to a differing power conversion apparatus, and the cell stack and the power conversion apparatus that are electrically connected to each other are disposed such that at least portions thereof overlap when viewed in the vertical direction.

[Aspect 4]

The electrochemical apparatus according to any one of aspects 1 to 3, further including: a ventilating unit (6) that ventilates the housing space by supplying air into the housing space from outside the heating tank.

[Aspect 5]

The electrochemical apparatus according to any one of aspects 1 to 4, in which: the electrochemical cell includes an air electrode (202) and a hydrogen electrode (201), and is configured to ventilate the housing space by supplying gas discharged from the air electrode into the housing space.

[Aspect 6]

The electrochemical apparatus according to any one of aspects 1 to 5, in which: the control unit is disposed further toward the lower side than the power conversion apparatus is.

[Aspect 7]

The electrochemical apparatus according to any one of aspects 1 to 6, further including: a discharge flow path (22) through which gas discharged from the cell stack flows, in which the discharge flow path passes through the wall portion of the heating tank and extends outside the heating tank from the cell stack; a discharge flow path heat exchanger (71) is disposed in the housing space and cools gas flowing through the discharge flow path, and the power conversion apparatus is configured to be cooled by cooling water, and the cooling water is configured to cool the gas flowing through the discharge flow path by flowing into the discharge flow path heat exchanger after cooling the power conversion apparatus.
Here, reference numbers in parentheses given in the aspects described above indicate corresponding relationships with specific means described in embodiments described above and do not limit the technical scope of the present disclosure.

Claims

What is claimed is:

1. An electrochemical apparatus, comprising:

a cell stack configured by a plurality of electrochemical cells being stacked;

a power conversion apparatus that is electrically connected to the cell stack;

a control unit that controls the power conversion apparatus; and

a heating tank that includes a housing space housing the cell stack and heats the cell stack, wherein

the cell stack is configured to produce hydrogen by electrolyzing water using supplied power, or generate power through an electrochemical reaction between hydrogen and an oxidizing agent,

the power conversion apparatus is disposed outside the heating tank, further toward a lower side than the cell stack is,

the power conversion apparatus and the cell stack are electrically connected by a conductor that passes through a wall portion of the heating tank, and

the power conversion apparatus is disposed such that at least a portion thereof overlaps the heating tank when viewed in a vertical direction.

2. The electrochemical apparatus according to claim 1, wherein:

the power conversion apparatus is disposed such that at least a portion thereof overlaps the cell stack when viewed in the vertical direction.

3. The electrochemical apparatus according to claim 2, further comprising:

a plurality of cell stacks and a plurality of power conversion apparatuses, wherein

the plurality of cell stacks are each electrically connected to respective power conversion apparatuses, and the cell stack and the power conversion apparatus that are electrically connected to each other are disposed such that at least portions thereof overlap when viewed in the vertical direction.

4. The electrochemical apparatus according to claim 1, further comprising:

a ventilating unit that ventilates the housing space by supplying air into the housing space from outside the heating tank.

5. The electrochemical apparatus according to claim 1, wherein:

the electrochemical cell includes an air electrode and a hydrogen electrode, and is configured to ventilate the housing space by supplying gas discharged from the air electrode into the housing space.

6. The electrochemical apparatus according to claim 1, wherein:

the control unit is disposed further toward the lower side than the power conversion apparatus is.

7. The electrochemical apparatus according to claim 1, further comprising:

a discharge flow path through which gas discharged from the cell stack flows, wherein

the discharge flow path passes through the wall portion of the heating tank and extends outside the heating tank from the cell stack;

a discharge flow path heat exchanger is disposed in the housing space and cools gas flowing through the discharge flow path, and

the power conversion apparatus is configured to be cooled by cooling water, and the cooling water is configured to cool the gas flowing through the discharge flow path by flowing into the discharge flow path heat exchanger after cooling the power conversion apparatus.

8. The electrochemical apparatus according to claim 2, further comprising:

9. The electrochemical apparatus according to claim 2, wherein:

10. The electrochemical apparatus according to claim 2, wherein:

11. The electrochemical apparatus according to claim 2, further comprising: