Electrochemical device

Abstract

To provide an electrochemical device capable of achieving miniaturization and efficiency of electric power, and improving safety.SOLUTION: The electrochemical device 1 includes a cell stack 2, a power converter 3, a controller 4, and a heating tank 5. The electric power converter 3 is electrically connected to the cell stack 2. The controller 4 controls the power conversion device 3. The heating tank 5 has a housing space 50 for housing the cell stack 2 and heats the cell stack 2. The cell stack 2 is configured to electrolyze water by supplied electric power to produce hydrogen, or is configured to generate electric power by an electrochemical reaction between hydrogen and an oxidant. The power converter 3 is disposed outside the heat tank 5 and on the Z1 below the cell stack 2. The power converter 3 is disposed so as to at least partially overlap the heating tank 5 when viewed in the vertical direction Z.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to electrochemical devices. [Background technology]

[0002] For example, as disclosed in Patent Document 1, a fuel cell system is known that includes a fuel cell stack that uses hydrogen as fuel, a control device that controls the amount of power generated by the fuel cell stack, and a power conversion device that converts the DC power generated by the fuel cell stack into required power specifications. In the fuel cell system described in Patent Document 1, the fuel cell stack, control device, and power conversion device are housed in a housing. The housing also has an opening / closing door that can be opened and closed relative to the housing main body, and the power conversion device and control device are attached to the opening / closing door. This allows for a simple and compact configuration and facilitates maintenance of the power conversion device and other components inside the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-228180 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the fuel cell system described in Patent Document 1, the power conversion device is located at a position distant from the fuel cell stack. Therefore, the wiring electrically connecting the power conversion device and the fuel cell stack tends to be long. This tends to increase power loss and lead to an increase in size. Furthermore, in the fuel cell system described in Patent Document 1, the power conversion device is located in the upper part of the housing. Therefore, it can be said that there is room for improvement from the perspective of ensuring safety against hydrogen gas leakage.

[0005] The present invention has been made in view of the above problems, and aims to provide an electrochemical device that can be made smaller and more power efficient, while also improving safety. [Means for solving the problem]

[0006] One aspect of the present invention is a fuel cell system including: a cell stack (2) formed by stacking a plurality of electrochemical cells (20); a power converter (3) electrically connected to the cell stack; a control unit (4) for controlling the power conversion device; a storage space (50) for storing the cell stack and a heating tank (5) for heating the cell stack; the cell stack is configured to produce hydrogen by electrolyzing water using supplied power, or to generate electricity through an electrochemical reaction between hydrogen and an oxidant, the power conversion device is disposed outside the heating tank and below the cell stack (Z1); the power converter and the cell stack are electrically connected via a conductor (11) that penetrates a wall (51) of the heating tank; The power converter is located in an electrochemical device (1) that is arranged so that at least a portion of the power converter overlaps with the heating tank when viewed from the vertical direction (Z). [Effects of the Invention]

[0007] In the electrochemical device, the power converter is positioned so that at least a portion of the power converter overlaps with the heating tank when viewed from above. This makes it easier to shorten the length of the conductors electrically connecting the power converter and the cell stack. As a result, the electrochemical device can be made smaller and more efficient in terms of power consumption.

[0008] In addition, in the electrochemical device, the power converter is disposed outside the heating chamber and below the cell stack. Therefore, even if hydrogen gas leaks from the cell stack, the power converter is unlikely to become an ignition source. As a result, safety can be improved.

[0009] As described above, according to the above aspect, it is possible to provide an electrochemical device that can be made smaller and more efficient in terms of power consumption, while also improving safety. In addition, the symbols in parentheses described in the claims and the means for solving the problems indicate the correspondence with the specific means described in the embodiments described below, and do not limit the technical scope of the present invention. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of an electrochemical device according to a first embodiment. [Figure 2] 1 is a cross-sectional view taken along the vertical direction of an electrochemical device according to a first embodiment. [Figure 3] FIG. 2 is a top view of the electrochemical device according to the first embodiment. [Figure 4] FIG. 1 is a cross-sectional view of an electrochemical cell according to a first embodiment. [Figure 5] FIG. 10 is a cross-sectional view taken along the vertical direction of the electrochemical device according to the second embodiment. [Figure 6] FIG. 11 is a cross-sectional view taken along the vertical direction of the electrochemical device according to the third embodiment. [Figure 7] FIG. 10 is a vertical cross-sectional view of an electrochemical device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Embodiment 1) An embodiment of the electrochemical device will be described with reference to FIGS. As shown in Figs. 1 and 2, the electrochemical device 1 of this embodiment includes a cell stack 2, a power converter 3, a control unit 4, and a heating tank 5. As shown in Fig. 2, the cell stack 2 is formed by stacking a plurality of electrochemical cells 20. The power converter 3 is electrically connected to the cell stack 2. The control unit 4 controls the power converter 3. The heating tank 5 has a storage space 50 that stores the cell stack 2, and heats the cell stack 2.

[0012] The cell stack 2 is configured to produce hydrogen by electrolyzing water using supplied power, or to generate electricity through an electrochemical reaction between hydrogen and an oxidant.

[0013] The power converter 3 is disposed outside the heating tank 5 and is disposed below the cell stack 2 in a direction Z1. The power converter 3 and the cell stack 2 are electrically connected via a conductor 11 that penetrates a wall 51 of the heating tank 5. As shown in FIG. 3 , the power converter 3 is disposed so that at least a portion of it overlaps with the heating tank 5 when viewed from the vertical direction Z.

[0014] The electrochemical device 1 can be used, for example, as a fuel cell that generates electricity by utilizing a reaction between hydrogen and oxygen as an oxidant, or as a hydrogen production device that produces hydrogen by electrolyzing water vapor using supplied power. The electrochemical device 1 of this embodiment is a hydrogen production device that produces hydrogen. In this embodiment, the cell stack 2 electrolyzes water, which is a raw material, using power supplied from a power source 10 (see FIG. 2) via a power conversion device 3 to produce hydrogen.

[0015] In the cell stack 2, the electrochemical cells 20 are electrically connected in series. In this embodiment, the electrochemical cells 20 constituting the cell stack 2 are SOECs (Solid Oxide Electrolysis Cells). As shown in FIG. 4, the electrochemical cells 20 have an air electrode 202 and a hydrogen electrode 201, and further include an electrolyte 203 interposed between the hydrogen electrode 201 and the air electrode 202.

[0016] In this embodiment, a gas containing water vapor is supplied to the hydrogen electrode 201, and air is supplied to the air electrode 202. In other words, water to be electrolyzed is supplied to the hydrogen electrode 201 in the form of water vapor. The electrolyte 203 is made of solid oxide ceramic and contains oxide ions (O 2- The electrolyte 203 can be made of, for example, yttria-stabilized zirconia, perovskite-type oxide, or the like.

[0017] The water vapor supplied to the electrochemical cell 20 is converted into "H2O+2e - →H2+O 2- In addition, the cathode 202 undergoes an electrolytic reaction of "O 2- →1 / 2O2+2e - That is, at the hydrogen electrode 201, water vapor is electrolyzed to produce hydrogen gas and oxide ions (O 2- ) occurs. The oxide ions move through the electrolyte 203 toward the air electrode 202, where they are oxidized to form oxygen gas. The hydrogen-containing gas produced by this electrolytic reaction is discharged from the hydrogen electrode 201 to the outside of the electrochemical cell 20, and the oxygen-containing gas produced is also discharged from the air electrode 202 to the outside of the electrochemical cell 20.

[0018] In this embodiment, the power conversion device 3 supplies power to the cell stack 2. Specifically, the power conversion device 3 converts AC power from the power source 10 shown in FIG.

[0019] As shown in FIG. 3 , when viewed from the vertical direction Z, the power converter 3 is arranged so that more than half of its projection area projected in the vertical direction Z overlaps with the heating tank 5. When viewed from the vertical direction Z, the power converter 3 is arranged so that its entirety overlaps with the heating tank 5. When viewed from the vertical direction Z, the power converter 3 is arranged so that at least a portion of it overlaps with the cell stack 2. When viewed from the vertical direction Z, the power converter 3 is arranged so that more than half of its projection area projected in the vertical direction Z overlaps with the cell stack 2. The vertical direction Z is a direction along the vertical direction.

[0020] Of the power converter 3 and the cell stack 2, the one with a smaller area of ​​the projected region projected in the vertical direction Z is referred to as the small-area section 18, and the one with a larger area of ​​the projected region projected in the vertical direction Z is referred to as the large-area section 19. In this embodiment, the small-area section 18 is arranged such that, when viewed from the vertical direction Z, more than half of its projected region projected in the vertical direction Z overlaps with the large-area section 19. Furthermore, the large-area section 19 is arranged such that, when viewed from the vertical direction Z, more than half of its projected region projected in the vertical direction Z overlaps with the small-area section 18. In this embodiment, the small-area section 18 is arranged such that, when viewed from the vertical direction Z, its entirety overlaps with the large-area section 19. Furthermore, in this embodiment, the small-area section 18 is the power converter 3, and the large-area section 19 is the cell stack 2.

[0021] The electrochemical device 1 of this embodiment includes a plurality of cell stacks 2 and a plurality of power converters 3. Each of the plurality of cell stacks 2 is electrically connected to a separate power converter 3. The electrically connected cell stacks 2 and the power converters 3 are arranged so that they at least partially overlap each other when viewed in the vertical direction Z. In this embodiment, in the small-area portion 18 and the large-area portion 19 that are electrically connected to each other, the small-area portion 18 is arranged so that, when viewed in the vertical direction Z, more than half of the projected area of ​​the small-area portion 18 overlaps with the large-area portion 19. In addition, in the small-area portion 18 and the large-area portion 19 that are electrically connected to each other, the large-area portion 19 is arranged so that, when viewed in the vertical direction Z, more than half of the projected area of ​​the large-area portion 19 overlaps with the small-area portion 18. In this embodiment, in the small-area portion 18 and the large-area portion 19 that are electrically connected to each other, the small-area portion 18 is arranged so that, when viewed in the vertical direction Z, the small-area portion 18 entirely overlaps with the large-area portion 19. In this embodiment, the number of cell stacks 2 and the number of power converters 3 are the same.

[0022] Furthermore, the wall 51 of the heating tank 5 is covered with a heat insulating material (not shown) on the side facing the storage space 50. In other words, the cell stack 2 is housed in the storage space 50 that is covered with the heat insulating material. The heating tank 5 heats and keeps the cell stack 2 warm to a temperature suitable for the electrolysis of water.

[0023] 2, the heating tank 5 has a cell heating unit 52 for heating the cell stack 2 within the accommodation space 50. The cell heating unit 52 can be, for example, an electric heater, a combustor, a heat exchanger, etc. The control unit 4 controls the cell heating unit 52 to adjust the temperature of the cell stack 2 to, for example, 550 to 850°C.

[0024] An apparatus housing chamber 53 for housing the power converter 3 is provided on a lower side Z1 of the bottom wall 511 of the heating tank 5. In addition to the power converter 3, a control unit 4 is also arranged in an inner space 530, which is the space inside the apparatus housing chamber 53. The wall covering the upper side Z2 of the inner space 530 is also the bottom wall 511 of the heating tank 5.

[0025] As shown in Figures 1 and 2, the cell stack 2 and the power converter 3 are directly connected by a bus bar, which is a conductor 11. As shown in Figure 2, the cell stack 2 and the power converter 3 face each other in the vertical direction Z, via the bottom wall 511 of the heating tank 5, which is provided with a heat insulating material. In other words, the cell stack 2 and the power converter 3 are arranged so as to sandwich the bottom wall 511 in the vertical direction Z. In addition, the bus bar 11 penetrates the bottom wall 511 of the heating tank 5.

[0026] The control unit 4 is disposed on the lower side Z1 than the power conversion device 3. In this embodiment, the control unit 4 controls the power conversion device 3 to adjust the power supplied to the cell stack 2. The control unit 4 has a processor and a memory.

[0027] The electrochemical device 1 of this embodiment also includes a ventilation unit 6. The ventilation unit 6 supplies air from the outside of the heating tank 5 into the accommodation space 50, thereby ventilating the accommodation space 50.

[0028] In this embodiment, the ventilation unit 6 is installed near the bottom wall 511 and is also provided on the wall 51 of the heating tank 5. The ventilation unit 6 can be, for example, a blower fan.

[0029] A ventilation hole 510 that connects the storage space 50 to the outside is formed in the top plate portion 512 of the wall portion 51 of the heating tank 5. Air supplied into the storage space 50 by the ventilation unit 6 is discharged to the outside of the storage space 50 through the ventilation hole 510. In the heating tank 5, the ventilation hole 510 is formed at a position away from the ventilation unit 6. As shown in FIG. 3 , the ventilation hole 510 and the ventilation unit 6 are located at diagonal corners of the heating tank 5 when viewed from the vertical direction Z.

[0030] 2, the electrochemical device 1 is provided with an exhaust flow path 22 through which gas discharged from the cell stack 2 flows. The exhaust flow path 22 penetrates the wall 51 of the heating tank 5 and extends from the cell stack 2 to the outside of the heating tank 5.

[0031] The electrochemical device 1 also includes a discharge passage heat exchanger 71. The discharge passage heat exchanger 71 is disposed in the accommodation space 50 and cools the gas flowing through the discharge passage 22.

[0032] In this embodiment, the electrochemical device 1 includes, as the exhaust flow path 22, a hydrogen electrode exhaust flow path 221 and a cathode exhaust flow path 222. The hydrogen electrode exhaust flow path 221 is connected to the cell stack 2 and is a flow path through which gas exhausted from the hydrogen electrode 201 flows. The cathode exhaust flow path 222 is connected to the cell stack 2 and is a flow path through which gas exhausted from the cathode 202 flows. In this embodiment, gas containing hydrogen produced by the cell stack 2 flows through the hydrogen electrode exhaust flow path 221, and gas containing oxygen produced by the cell stack 2 flows through the cathode exhaust flow path 222.

[0033] In this embodiment, both the hydrogen electrode discharge flow path 221 and the air electrode discharge flow path 222 are connected to the discharge flow path heat exchanger 71. Gas discharged from the hydrogen electrode 201 passes through the hydrogen electrode discharge flow path 221 and the discharge flow path heat exchanger 71, and then passes through the hydrogen electrode discharge flow path 221 to be discharged from the accommodation space 50 to the outside of the heating tank 5. Gas discharged from the air electrode 202 passes through the air electrode discharge flow path 222 and the discharge flow path heat exchanger 71, and then passes through the air electrode discharge flow path 222 to be discharged from the accommodation space 50 to the outside of the heating tank 5.

[0034] The electrochemical device 1 of this embodiment also includes a water vapor supply channel 211 that supplies a gas containing water vapor to the hydrogen electrode 201 of the electrochemical cell 20, and an air supply channel 212 that supplies air to the air electrode 202. Both the water vapor supply channel 211 and the air supply channel 212 penetrate the wall portion 51 of the heating chamber 5 and extend from the outside of the heating chamber 5 to the cell stack 2 in the accommodation space 50. Both the water vapor supply channel 211 and the air supply channel 212 are connected to the discharge channel heat exchanger 71. In this embodiment, the water vapor-containing gas and air are supplied to the cell stack 2 after their temperatures are increased by passing through the water vapor supply channel 211 or the air supply channel 212 and the discharge channel heat exchanger 71. That is, the temperatures of both the gas flowing through the water vapor supply channel 211 and the gas flowing through the air supply channel 212 are increased by heat exchange with the gas flowing through the discharge channel 22 in the discharge channel heat exchanger 71.

[0035] The discharge flow path heat exchanger 71 may be, for example, a heat exchanger group including a plurality of heat exchangers. In this case, the discharge flow path heat exchanger 71 may include, for example, a heat exchanger that performs heat exchange between gas flowing through the water vapor supply flow path 211 and gas flowing through the hydrogen electrode discharge flow path 221, or a heat exchanger that performs heat exchange between gas flowing through the water vapor supply flow path 211 and gas flowing through the cathode discharge flow path 222. The discharge flow path heat exchanger 71 may also include, for example, a heat exchanger that performs heat exchange between gas flowing through the air supply flow path 212 and gas flowing through the hydrogen electrode discharge flow path 221, or a heat exchanger that performs heat exchange between gas flowing through the air supply flow path 212 and gas flowing through the cathode discharge flow path 222.

[0036] Furthermore, outside the heating tank 5, an evaporator 13 is provided in the water vapor supply passage 211. The evaporator 13 evaporates liquid water to generate water vapor. The water vapor generated by the evaporator 13 passes through the water vapor supply passage 211 and is supplied to the hydrogen electrode 201. The temperature of the water vapor generated by the evaporator 13 can be, for example, approximately 150°C. Furthermore, the evaporator 13 can include, for example, a heater or a heat pump for heating the liquid water.

[0037] The electrochemical device 1 is connected to the evaporator 13 and includes a water supply flow path 214 that supplies water to the evaporator 13. A water pump 14 and a water purifier 15 are provided in the water supply flow path 214. The water pump 14 supplies water to the evaporator 13 via the water purifier 15. The water purifier 15 purifies the water supplied from the water pump 14 into pure water by removing particulate matter, ions, and the like contained in the water supplied from the water pump 14. The water purifier 15 can be, for example, a device including a reverse osmosis membrane, an ion exchange resin, or the like.

[0038] Furthermore, outside the heating tank 5, an air pump 12 is provided in the air supply passage 212. The air pump 12 supplies pressurized air to the air electrode 202.

[0039] Additionally, an external heat exchanger 72 is provided in the hydrogen electrode discharge passage 221 outside the heating tank 5. Cooling water is introduced into the external heat exchanger 72. The external heat exchanger 72 can cool the gas flowing through the hydrogen electrode discharge passage 221 from approximately 500°C to approximately 10°C, for example.

[0040] Next, the effects of this embodiment will be described. In the electrochemical device 1, the power converter 3 is disposed so that at least a portion thereof overlaps with the heating tank 5 when viewed from the vertical direction Z. This makes it easy to shorten the length of the conductor 11 that electrically connects the power converter 3 and the cell stack 2. As a result, the electrochemical device 1 can be made smaller and power efficiency can be improved.

[0041] Furthermore, in the electrochemical device 1, the power converter 3 is disposed outside the heating tank 5 and is disposed below the cell stack 2 in the Z1 direction. Therefore, even if hydrogen gas leaks from the cell stack 2, the power converter 3 is unlikely to become an ignition source. As a result, safety can be improved.

[0042] In other words, since the length of the conductor 11 is shorter, the space required for installing the conductor 11 can be reduced, allowing for a more compact electrochemical device 1. Furthermore, the shorter the length of the conductor 11, the less loss of power supplied from the power converter 3 to the cell stack 2 tends to occur, allowing for more efficient power consumption. Furthermore, hydrogen is lighter than air and therefore tends to move toward the upper side Z2. Therefore, by placing the power converter 3 on the lower side Z1 than the cell stack 2, it is possible to prevent the power converter 3 from becoming an ignition source even in the unlikely event that hydrogen leaks from the cell stack 2. This allows for improved safety.

[0043] When viewed from the vertical direction Z, the power converter 3 is disposed so that at least a portion thereof overlaps with the cell stack 2. This makes it easier to further shorten the length of the conductor 11. As a result, the electrochemical device 1 can be further miniaturized, and power efficiency can be further improved.

[0044] Furthermore, the cell stack 2 and the power converter 3 are arranged so as to sandwich the bottom wall 511 of the heating tank 5 in the vertical direction Z. This allows the length of the conductor 11 in the vertical direction Z to be further shortened. As a result, the electrochemical device 1 can be further miniaturized, and power efficiency can be further improved.

[0045] The electrochemical device 1 of this embodiment includes a plurality of cell stacks 2 and a plurality of power converters 3. Each of the plurality of cell stacks 2 is electrically connected to a separate power converter 3. Therefore, power can be supplied from the power converter 3 to the cell stack 2 individually according to each cell stack 2. This makes it possible to supply power according to the deterioration state of the cell stack 2, etc. As a result, the life of each cell stack 2 can be extended. Furthermore, the cell stacks 2 and the power converters 3, which are electrically connected to each other, are arranged so that at least a portion of them overlap when viewed from the vertical direction Z. This allows the electrochemical device 1 to be made smaller and more efficient in terms of power.

[0046] The electrochemical device 1 of this embodiment includes a ventilation unit 6. Therefore, even if hydrogen-containing gas leaks from the cell stack 2, the hydrogen can be efficiently discharged from the accommodation space 50 to the outside. As a result, safety can be further improved.

[0047] The control unit 4 is disposed on the lower side Z1 than the power converter 3. Therefore, even if water leaks in the electrochemical device 1 or the electrochemical device 1 is submerged in water, the control unit 4 is stopped first, thereby stopping the operation of the entire electrochemical device 1. As a result, safety can be further improved.

[0048] In this embodiment, the cell stack 2 and the power converter 3 are directly connected by the bus bar 11. This allows the electrochemical device 1 to be sufficiently miniaturized, and also allows for sufficient improvement in power efficiency.

[0049] As described above, according to this embodiment, it is possible to provide an electrochemical device 1 that can be made smaller and more efficient in terms of power consumption, while also improving safety.

[0050] In the first embodiment, air is supplied to the air electrode 202. However, the electrochemical device may also be configured to supply, for example, a gas with a lower oxygen partial pressure than air to the air electrode.

[0051] (Embodiment 2) This embodiment is different from the first embodiment in the ventilation means for the accommodation space 50.

[0052] The electrochemical device 1 of this embodiment is configured to ventilate the accommodation space 50 by supplying gas discharged from the air electrode 202 (see FIG. 4 of the first embodiment) into the accommodation space 50.

[0053] 5 , the electrochemical device 1 of this embodiment includes an intra-space discharge flow path 23 through which gas discharged from the air electrode 202 flows and in which a gas discharge port 231 is disposed within the accommodation space 50. The intra-space discharge flow path 23 is connected to the cell stack 2. In this embodiment, the gas discharged from the air electrode 202 passes through the intra-space discharge flow path 23 and is then supplied from the discharge port 231 into the accommodation space 50. Other aspects are the same as those of embodiment 1. Note that, among the symbols used in embodiment 2 and onwards, the same symbols as those used in the previous embodiments represent the same components, etc. as those in the previous embodiments, unless otherwise specified.

[0054] The electrochemical device 1 of this embodiment is configured to ventilate the storage space 50 by supplying gas exhausted from the air electrode 202 into the storage space 50. Therefore, even if hydrogen-containing gas leaks from the cell stack 2, the hydrogen can be efficiently exhausted from the storage space 50 to the outside. As a result, safety can be further improved. In addition, because the exhaust gas from the air electrode 202 is used for ventilation, the storage space 50 can be ventilated without the need for a new device or the like. As a result, the electrochemical device 1 can be further miniaturized while further improving safety. In addition, the same effects as those of the first embodiment are achieved.

[0055] (Embodiment 3) As shown in FIG. 6, this embodiment is different from the first embodiment in the configuration of the water supply channel 214.

[0056] In this embodiment, the power converter 3 is configured to be cooled by cooling water. After cooling the power converter 3, the cooling water flows into the exhaust flow path heat exchanger 71, thereby cooling the gas flowing through the exhaust flow path 22.

[0057] In this embodiment, the water supply passage 214 extending from the water purifier 15 penetrates the wall of the device accommodation chamber 53 and is connected to the power converters 3 arranged in the inner space 530. Within the inner space 530, the water supply passage 214 branches and is connected to each of the power converters 3. That is, the water that has passed through the water purifier 15 is supplied to each of the power converters 3 as cooling water. The cooling waters supplied to each of the power converters 3 merge after passing through the power converters 3. The water supply passage 214 through which the merged cooling water flows penetrates the bottom wall 511 and extends from the inner space 530 to the accommodation space 50, and is connected to the discharge passage heat exchanger 71. That is, the cooling water that has cooled the power converters 3 passes through the water supply passage 214 and the discharge passage heat exchanger 71, and is then supplied to the evaporator 13 through the water supply passage 214.

[0058] Here, when the temperature of the cooling water introduced into the power converter 3 is approximately 30°C, the temperature of the cooling water discharged from the power converter 3 becomes, for example, approximately 40°C. The cooling water at approximately 40°C is then introduced into the exhaust flow path heat exchanger 71 and exchanges heat with the gas discharged from the cell stack 2, and is then discharged from the exhaust flow path heat exchanger 71 at, for example, approximately 80°C. The cooling water at approximately 80°C is then introduced into the evaporator 13, where it is heated to become water vapor. The water vapor generated from the cooling water is again introduced into the exhaust flow path heat exchanger 71, where it exchanges heat with the gas discharged from the cell stack 2, and after its temperature has increased, is introduced into the cell stack 2.

[0059] The gas discharged from the hydrogen electrode 201 is introduced into the discharge flow path heat exchanger 71 through the hydrogen electrode discharge flow path 221. The gas discharged from the hydrogen electrode 201 is cooled, for example, from about 700°C to about 500°C in the discharge flow path heat exchanger 71 by heat exchange with the cooling water from the power converter 3 and the water vapor from the evaporator 13. Thereafter, the gas discharged from the hydrogen electrode 201 is cooled, for example, to about 10°C by the external heat exchanger 72.

[0060] Like the gas discharged from the hydrogen electrode 201, the gas discharged from the air electrode 202 is cooled, for example, from about 700°C to about 500°C in the discharge flow path heat exchanger 71 by heat exchange with cooling water from the power converter 3. Thereafter, the gas discharged from the air electrode 202 passes through the air electrode discharge flow path 222 and is discharged to the outside of the heating tank 5.

[0061] When the discharge flow path heat exchanger 71 is a heat exchanger group, the discharge flow path heat exchanger 71 may include, for example, a heat exchanger that exchanges heat between water flowing through the water supply flow path 214 and gas flowing through the hydrogen electrode discharge flow path 221, or a heat exchanger that exchanges heat between water flowing through the water supply flow path 214 and gas flowing through the air electrode discharge flow path 222.

[0062] In addition, in this embodiment, a branch flow path 215 is provided which branches off from the water supply flow path 214 which connects the power converter 3 and the discharge flow path heat exchanger 71. The branch flow path 215 penetrates the wall portion 51 of the heating tank 5 and extends from the water supply flow path 214 to the outside of the accommodation space 50.

[0063] The electrochemical device 1 also has a temperature measuring unit 216 that measures the temperature of the water flowing through the branch flow path 215. The branch flow path 215 is also provided with a flow rate adjusting unit (not shown) that adjusts the amount of water supplied from the water supply flow path 214 to the branch flow path 215. The flow rate adjusting unit provided in the branch flow path 215 can be, for example, an electromagnetic valve.

[0064] In the electrochemical device 1 of this embodiment, a coolant heat exchanger 17 is provided in the water supply passage 214 near the water pump 14, which is capable of exchanging heat between the water flowing through the branch passage 215 and the water supply passage 214. The evaporator 13 is also equipped with a heat pump (not shown), and is configured to use the water from the branch passage 215 as a heat source for the heat pump. That is, the branch passage 215 branches (not shown) outside the heating tank 5 and is connected to the coolant heat exchanger 17 and the evaporator 13, respectively. The branch passage 215 connected to the coolant heat exchanger 17 or the heat pump is also provided with a flow rate adjuster for adjusting the flow rate of water.

[0065] The electrochemical device 1 of this embodiment is configured to adjust the flow rate of water flowing through the branch flow path 215 under control of the control unit 4. The control unit 4 calculates the amount of water to be supplied to the coolant heat exchanger 17 and the heat pump based on information such as the temperature of the water flowing through the branch flow path 215 and the amount of heat required by the coolant heat exchanger 17 and the heat pump of the evaporator 13. Then, based on the calculation result, the control unit 4 controls the flow rate adjustment unit provided in the branch flow path 215 to adjust the amount of water to be supplied to the coolant heat exchanger 17 and the heat pump. In other words, the control unit 4 prioritizes the coolant heat exchanger 17 and the evaporator 13 and then adjusts the amount of water to be supplied. The rest is the same as in the first embodiment.

[0066] In this embodiment, the power converter 3 is configured to be cooled by cooling water. After cooling the power converter 3, the cooling water flows into the discharge passage heat exchanger 71, thereby cooling the gas flowing through the discharge passage 22. Therefore, the power converter 3 and the gas flowing through the discharge passage 22 can be efficiently cooled by the cooling water. As a result, the energy efficiency of the electrochemical device 1 can be improved.

[0067] The electrochemical device 1 of this embodiment includes a branch flow path 215 branching from the water supply flow path 214. This allows for effective use of the exhaust heat emitted from the power converter 3. That is, water heated by the power converter 3 can be supplied to the coolant heat exchanger 17 and the heat pump of the evaporator 13 via the branch flow path 215. This allows the exhaust heat from the power converter 3 to be used to prevent the coolant heat exchanger 17 from freezing the water supply flow path 214, or to be used as a heat source for the heat pump. This allows for improved energy efficiency and operational reliability of the electrochemical device 1.

[0068] Furthermore, in this embodiment, the water introduced into both the power converter 3 and the exhaust flow path heat exchanger 71 is configured to be supplied to the evaporator 13. Therefore, water whose temperature has been increased by the exhaust heat from both the power converter 3 and the exhaust flow path 22 can be supplied to the evaporator 13. As a result, energy efficiency can be further improved.

[0069] The electrochemical device 1 is configured to adjust the flow rate of water flowing through the branch flow path 215 using the control unit 4. Therefore, the water flowing through the branch flow path 215 can be supplied to each device according to the amount of heat required by the coolant heat exchanger 17, the evaporator 13, etc. As a result, energy efficiency can be further improved. In addition, the same effects as those of the first embodiment are achieved.

[0070] In the third embodiment, the branch flow path 215 branches off from the water supply flow path 214 that connects the power converter 3 and the discharge flow path heat exchanger 71. However, the branch flow path may also branch off from the water supply flow path that connects the discharge flow path heat exchanger and the evaporator, for example.

[0071] The water flowing through the branch flow path 215 can also be used, for example, as cooling water flowing through the external heat exchanger 72, or to prevent freezing of the air supply flow path 212. The water flowing through the branch flow path 215 can also be used, for example, as a heat source for a polymer electrolyte membrane (PEM) water electrolysis device or an ammonia synthesizer.

[0072] (Embodiment 4) In this embodiment, the cell stack 2 functions as a fuel cell. That is, the cell stack 2 is configured to generate electricity through an electrochemical reaction between hydrogen and an oxidant.

[0073] In this embodiment, the electrochemical cell 20 of the cell stack 2 is an SOFC (Solid Oxide Fuel Cell). In the cell stack 2, air containing oxygen as an oxidant is supplied to the air electrode 202 (see FIG. 4 of the first embodiment) of the electrochemical cell 20, and gas containing hydrogen is supplied to the hydrogen electrode 201 (see FIG. 4 of the first embodiment) of the electrochemical cell 20.

[0074] 7, the electrochemical device 1 of this embodiment includes a hydrogen supply channel 213 that supplies a gas containing hydrogen to the hydrogen electrode of the cell stack 2. In addition, an air supply channel 212 supplies air to the air electrode of the cell stack 2.

[0075] The electrochemical device 1 of this embodiment includes a hydrogen supply unit 16 that supplies a 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. The hydrogen supply unit 16 can be, for example, a reformer. The reformer reforms methane gas or city gas containing methane as a main component through a catalytic reaction to generate a gas containing hydrogen gas. The hydrogen supply unit 16 can also be, for example, a storage tank that stores hydrogen gas.

[0076] When the discharge flow path heat exchanger 71 is a heat exchanger group, the discharge flow path heat exchanger 71 may include, for example, a heat exchanger that exchanges heat between gas flowing through the hydrogen supply flow path 213 and gas flowing through the hydrogen electrode discharge flow path 221, or a heat exchanger that exchanges heat between gas flowing through the hydrogen supply flow path 213 and gas flowing through the air electrode discharge flow path 222.

[0077] Next, the reactions that occur in the cell stack 2 during power generation will be described. In this embodiment, oxygen is reduced at the air electrode of the electrochemical cell 20 to generate oxide ions. Furthermore, a reaction occurs at the hydrogen electrode to generate protons and electrons from the fuel hydrogen. The generated electrons then flow to the power converter 3, and the protons react with oxide ions that have migrated to the hydrogen electrode side through the electrolyte, generating water vapor. The water vapor generated at the hydrogen electrode is discharged into the hydrogen electrode discharge flow path 221, and the air after oxygen has been consumed at the air electrode is discharged into the air electrode discharge flow path 222.

[0078] The power conversion device 3 is also electrically connected to an external load (not shown). In this embodiment, the power conversion device 3 converts the output power of the cell stack 2. Specifically, the power conversion device 3 converts DC power, which is the output power of the cell stack 2, to AC power and converts the magnitude of the voltage in accordance with the external load to which the power is output. The rest is the same as in the first embodiment.

[0079] In this embodiment, the power converter 3 is also arranged so that at least a portion thereof overlaps with the heating tank 5 when viewed from the vertical direction Z. This makes it easy to shorten the length of the conductor 11. As a result, the electrochemical device 1 can be made more compact and power efficiency can be improved. Furthermore, because the power converter 3 is arranged below the cell stack 2 in the Z1 direction, the power converter 3 is unlikely to become an ignition source even in the unlikely event that hydrogen leaks from the cell stack 2. In addition, the same effects as those of the first embodiment are achieved.

[0080] In the above-described embodiment 4, air is supplied to the air electrode. However, the electrochemical device may also be configured to supply, for example, a gas with a higher oxygen partial pressure than air to the air electrode.

[0081] In the above-described first to fourth embodiments, the cell stack 2 and the power converter 3 are directly connected by the bus bar 11. However, for example, the cell stack and the power converter can also be electrically connected to each other by connecting the bus bar connected to the cell stack and the bus bar connected to the power converter to each other via a conductive member.

[0082] In the above-described first to fourth embodiments, the electrochemical device 1 includes a plurality of cell stacks 2 and a plurality of power converters 3. However, the electrochemical device may also be configured to include one cell stack and one power converter. The electrochemical device may also be configured to include two cell stacks and two electrochemical devices, or may also be configured to include three or more cell stacks and three or more electrochemical devices.

[0083] The present invention is not limited to the above-described embodiments, and can be applied to various embodiments within the scope of the present invention.

[0084] <Other> The features of the present invention are as follows. [Section 1] a cell stack (2) formed by stacking a plurality of electrochemical cells (20); a power converter (3) electrically connected to the cell stack; a control unit (4) for controlling the power conversion device; a storage space (50) for storing the cell stack and a heating tank (5) for heating the cell stack; the cell stack is configured to produce hydrogen by electrolyzing water using supplied power, or to generate electricity through an electrochemical reaction between hydrogen and an oxidant, the power conversion device is disposed outside the heating tank and below the cell stack (Z1); the power converter and the cell stack are electrically connected via a conductor (11) that penetrates a wall (51) of the heating tank; The electrochemical device (1) is arranged so that at least a portion of the power converter overlaps with the heating tank when viewed from the vertical direction (Z). [Section 2] Item 2. The electrochemical device according to item 1, wherein the power converter is disposed so that at least a portion of the power converter overlaps with the cell stack when viewed from above and below. [Section 3] Item 3. The electrochemical device according to item 2, comprising a plurality of the cell stacks and a plurality of the power conversion devices, each of the plurality of cell stacks being electrically connected to a different one of the power conversion devices, and the cell stacks and the power conversion devices electrically connected to each other being arranged so that at least a portion of each of the cell stacks and the power conversion devices overlap each other when viewed from above and below. [Section 4] 4. The electrochemical device according to any one of items 1 to 3, further comprising a ventilation unit (6) that ventilates the storage space by supplying air from outside the heating tank into the storage space. [Section 5] 5. The electrochemical device according to any one of items 1 to 4, wherein the electrochemical cell has an air electrode (202) and a hydrogen electrode (201), and is configured to ventilate the accommodation space by supplying gas discharged from the air electrode into the accommodation space. [Section 6] 6. The electrochemical device according to any one of items 1 to 5, wherein the control unit is disposed below the power converter. [Section 7] a discharge flow path (22) through which gas discharged from the cell stack flows, the discharge flow path penetrating a wall portion of the heating tank and extending from the cell stack to the outside of the heating tank; a discharge flow path heat exchanger (71) that is disposed in the accommodation space and cools the gas flowing through the discharge flow path; 7. The electrochemical device according to any one of items 1 to 6, wherein the power conversion device is configured to be cooled by cooling water, and the cooling water is configured to cool the gas flowing through the exhaust flow path by flowing into the exhaust flow path heat exchanger after cooling the power conversion device. [Explanation of symbols]

[0085] 1... electrochemical device, 2... cell stack, 3... power converter, 4... control unit, 5... heating tank, 11... conductor, 20... electrochemical cell, 50... accommodation space, 51... wall portion, Z... vertical direction, Z1... lower side

Claims

1. a cell stack (2) formed by stacking a plurality of electrochemical cells (20); a power conversion device (3) electrically connected to the cell stack; A control unit (4) that controls the power conversion device; a storage space (50) for storing the cell stack and a heating tank (5) for heating the cell stack; the cell stack is configured to produce hydrogen by electrolyzing water using supplied power, or to generate electricity through an electrochemical reaction between hydrogen and an oxidant, the power conversion device is disposed outside the heating tank and below the cell stack (Z1); The power converter and the cell stack are electrically connected via a conductor (11) that penetrates a wall portion (51) of the heating tank, The electrochemical device (1) is arranged so that at least a portion of the power converter overlaps with the heating tank when viewed from the vertical direction (Z).

2. The electrochemical device according to claim 1 , wherein the power converter is disposed so that at least a portion of the power converter overlaps with the cell stack when viewed from above and below.

3. 3. The electrochemical device according to claim 2, comprising a plurality of the cell stacks and a plurality of the power conversion devices, wherein the plurality of cell stacks are each electrically connected to a different one of the power conversion devices, and the cell stacks and the power conversion devices that are electrically connected to each other are arranged so that at least a portion of each overlaps with each other when viewed from above and below.

4. 3. The electrochemical device according to claim 1, further comprising a ventilation section (6) that ventilates the accommodation space by supplying air from outside the heating tank into the accommodation space.

5. 3. The electrochemical device according to claim 1, wherein the electrochemical cell has an air electrode (202) and a hydrogen electrode (201), and is configured to ventilate the accommodation space by supplying gas discharged from the air electrode into the accommodation space.

6. The electrochemical device according to claim 1 or 2, wherein the control unit is disposed below the power conversion device.

7. an exhaust flow path (22) through which gas exhausted from the cell stack flows, the exhaust flow path penetrating a wall portion of the heating tank and extending from the cell stack to the outside of the heating tank; a discharge flow path heat exchanger (71) that is disposed in the accommodation space and cools the gas flowing through the discharge flow path; 3. The electrochemical device according to claim 1, wherein the power conversion device is configured to be cooled by cooling water, and the cooling water is configured to cool the gas flowing through the exhaust flow path by flowing into the exhaust flow path heat exchanger after cooling the power conversion device.

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