Fuel Cell System And Fuel Cell System Installation Section

An exemplary fuel cell system includes a fuel cell module, an air intake unit that takes air into the fuel cell module, and a housing that houses the fuel cell module and the air intake unit. The housing includes a first outer surface wall on which a desalination device is disposed upstream of the air intake unit, and a second outer surface wall provided with an electric wire arrangement part in which an electric wire is arranged.

This application claims foreign priority of JP2023-037044 filed Mar. 10, 2023, the disclosure of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a fuel cell system and an installation section thereof.

BACKGROUND ART

Conventionally, a configuration is known in which a desalination filter is attached to an opening formed in a housing container that houses a fuel cell system (see, for example, Patent Document 1). In Patent Document 1, the air that has passed through the desalination filter is sent to a fuel cell stack through a dedicated pipe.

PRIOR ART DOCUMENT

Patent Document

SUMMARY OF INVENTION

Technical Problem

The fuel cell system may be mounted on a ship. Further, the fuel cell system may be used on the coast of the sea. In these cases, it is particularly important to deal with salt damage, and a technique for suppressing the influence of salt damage is required. In addition, in the fuel cell system, for example, due to a layout or the like, a dedicated pipe connecting the desalination filter to the fuel cell stack may not be installed. In this case, a configuration is employed in which an air intake port is provided inside the housing, and it is considered that a salt damage countermeasure different from a conventional configuration is required.

An object of the present invention is to provide a technique capable of reducing the possibility of occurrence of an adverse effect due to salt damage in a fuel cell system.

Solution to Problem

An exemplary fuel cell system of the present invention includes a fuel cell module, an air intake unit that takes air into the fuel cell module, and a housing that houses the fuel cell module and the air intake unit. The housing includes a first outer surface wall on which a desalination device is disposed upstream of the air intake unit, and a second outer surface wall provided with an electric wire arrangement part in which an electric wire is arranged.

Advantageous Effects of Invention

According to an exemplary present invention, it is possible to reduce the possibility of occurrence of an adverse effect due to salt damage in a fuel cell system.

DESCRIPTION OF EMBODIMENTS

An embodiment of the present invention is described with reference to the drawings. In the drawings, the same reference numerals are given to the same or equivalent parts, and the description will not be repeated unless it is particularly necessary.

1. Overview of Fuel Cell System

FIG.1is a schematic perspective view illustrating an appearance of a fuel cell system100according to an embodiment of the present invention.FIG.2is a schematic diagram illustrating an internal configuration of the fuel cell system100according to the embodiment of the present invention. InFIG.2, arrows of a solid line, a one-dot chain line, and a two-dot chain line indicate a fluid passage (pipe in a detailed example) and a direction in which a fluid flows through a fluid passage. InFIG.2, a broken line indicates a wire. First, an overview of the fuel cell system100will be described with reference toFIGS.1and2.

As illustrated inFIG.1, the fuel cell system100includes a housing1. As illustrated inFIG.2, the housing1houses a fuel cell module2. In other words, the fuel cell system100includes the fuel cell module2. Specifically, the number of the fuel cell modules2accommodated in the housing1is four. However, the number of the fuel cell modules2accommodated in the housing1may be singular or a plurality other than four.

The fuel cell module2includes a fuel cell stack2a.Further, the fuel cell module2is configured to include a boost converter, a compressor for supplying air, and a pump for circulating a coolant (all of which are not illustrated). The fuel cell stack2ais configured with a plurality of stacked cells. Each cell includes a solid polymer electrolyte membrane, an anode electrode, a cathode electrode, and a pair of separators. The solid polymer electrolyte membrane is sandwiched between the anode electrode and the cathode electrode. The anode electrode is a negative electrode (fuel electrode). The anode electrode includes an anode catalyst layer and a gas diffusion layer. The cathode electrode is a positive electrode (air electrode). The cathode electrode includes a cathode catalyst layer and a gas diffusion layer. The anode electrode, the solid polymer electrolyte membrane, and the cathode electrode constitute a membrane electrode assembly (MEA). The pair of separators sandwich the membrane electrode assembly. Each separator has a plurality of grooves. Each groove of one separator forms a flow passage of hydrogen gas. Each groove of the other separator forms a flow passage of oxidant gas.

On the anode side, hydrogen is catalytically split into hydrogen ions and electrons. The hydrogen ions pass through the solid polymer electrolyte membrane and move to the cathode side. Meanwhile, the electrons move to the cathode side through an external circuit. As a result, a current is generated (electric power is generated). On the cathode electrode side, oxygen contained in the oxidant gas combines with the electrons that have flowed through the external circuit and the hydrogen ions that have passed through the solid polymer electrolyte membrane to produce water. The generated water is included in the exhaust gas and discharged to the outside of the fuel cell system100. The electric power generated by the fuel cell stack is boosted by the boost converter and extracted to the outside of the fuel cell system100.

In the fuel cell system100, measures against hydrogen leakage are appropriately taken from the perspective of safety. Further, even if hydrogen leaks, the fuel cell system100can safely process the leaked hydrogen. Furthermore, as illustrated inFIG.1, the fuel cell system100includes a desalination device3. The fuel cell system100is configured to be able to suppress salt damage by devising the disposition relating to the desalination device3. The fuel cell system100is not particularly limited, but is suitable for use in a ship, for example.

The housing1of the fuel cell system100has, for example, a rectangular parallelepiped shape. In the following description of the fuel cell system100, directions are defined as follows. A direction orthogonal to a horizontal floor surface on which the fuel cell system100is disposed is defined as an up-down direction, and a side on which the fuel cell system100is disposed with respect to the floor surface is defined as an upper side. In addition, front and rear are defined such that a side of the housing1on which the desalination device3is disposed is a front side and a side opposite to the front side of the housing1is a rear side. Left and right are defined such that the left-right direction is a direction orthogonal to the up-down direction and the front-rear direction, and that the left side when looking from the front to the rear is the left and the right side when looking from the front to the rear is the right. In a plan view of the housing1from above, the longitudinal direction of the housing1is the left-right direction, and the lateral direction is the front-rear direction. These directions are merely used for the purpose of illustration, and are not intended to limit the actual positional relation or directions.

2. Detailed Configuration of Fuel Cell System

As illustrated inFIG.2, the housing1includes a first section11and a second section12. The second section12is adjacent to the first section11. Specifically, the first section11and the second section12are arranged vertically. The first section11is disposed above the second section12. The configuration in which the first section11and the second section12are arranged in the vertical direction is an example, and another configuration may be employed. For example, the first section and the second section may be arranged side by side. The fuel cell module2is disposed in the first section11. An auxiliary machine relating to the operation of the fuel cell module2is disposed in the second section12.

The auxiliary machine will be described below.

The partition wall13sections the first section11and the second section12. The partition wall13constitutes a bottom wall of the first section11. Further, the partition wall13constitutes an upper wall of the second section12.

In addition to the partition wall13, the first section11includes a first section front wall11a,a first section rear wall11b,a first section left wall11c,a first section right wall11d,and a first section upper wall11e.The first section front wall11aconstitutes an upper portion of a front surface wall1aof the housing1. The first section rear wall11bconstitutes an upper portion of a rear surface wall1bof the housing1. The first section left wall11cconstitutes an upper portion of a left surface wall1cof the housing1. The first section right wall11dconstitutes an upper portion of a right surface wall1dof the housing1. The first section upper wall11econstitutes an upper surface wall1eof the housing1.

Further, in addition to the partition wall13, the second section12includes a second section front wall12a,a second section rear wall12b,a second section left wall12c,a second section right wall12d,and a second section bottom wall12e. The second section front wall12aconstitutes a lower portion of the front surface wall1aof the housing1. The second section rear wall12bconstitutes a lower portion of the rear surface wall1bof the housing1. The second section left wall12cconstitutes a lower portion of the left surface wall1cof the housing1. The second section right wall12dconstitutes a lower portion of the right surface wall1dof the housing1. The second section bottom wall12econstitutes a bottom surface wall1fof the housing1.

Specifically, the partition wall13airtightly sections the first section11and the second section12. In the present embodiment, as will be described in detail below, the first section11is a section from which hydrogen may leak. However, since the partition wall13for airtightly sectioning the two sections11and12is provided, even if hydrogen leaks from the first section11, hydrogen can be prevented from flowing into the second section12. For this reason, it is possible to eliminate the need for devices disposed in the second section12to have an explosion-proof structure against hydrogen. Further, it is possible to eliminate the need to provide a function of ventilating hydrogen that has leaked into the second section12.

FIG.3is a diagram for explaining a structure of the partition wall13provided inside the housing1. As illustrated inFIG.3, a part of the partition wall13has a through hole131penetrating in the up-down direction. The through hole131is provided to allow a member4such as a wire or a pipe to pass therethrough. That is, the fuel cell system100includes the member4which is disposed across the first section11and the second section12through the through hole131provided in the partition wall13. The member4may include at least one of a wire and a pipe. In the present embodiment, the member4includes a wire and a pipe. In the example illustrated inFIG.3, the member4is a wire41. In the partition wall13, one through hole131is provided for each of the plurality of wires41. However, this is merely an example, and one through hole131may be configured to collectively pass the plurality of wires41. The wires41include a power line and a signal line. The signal line includes a control line and a sensor line.

As illustrated inFIG.3, the partition wall13is provided with a seal structure132that closes a gap between the through hole131and the member4. Airtightness is secured by the seal structure132, and even if hydrogen leaks in the first section11, hydrogen can be prevented from flowing into the second section12. The seal structure132may be configured using, for example, a sealing material such as a silicone-based caulking agent.FIG.3illustrates a configuration for securing airtightness by using a sealing material. As another example, the seal structure132may be configured using a cable gland.

Even in a case where the member4disposed across the first section11and the second section12is a pipe, the same seal structure as in the case of the wire41may be applied.

FIGS.4A and4Bare diagrams for explaining another example of the through hole and the seal structure provided in the partition wall13. In the fuel cell system100according to the present embodiment, the pipes are configured as illustrated inFIGS.4A and4B.

FIG.4Ais an adapter133for disposing a plurality of pipes42across the first section11and the second section12. The adapter133includes a plate-shaped member1331integrated with the plurality of pipes42. The plate-shaped member1331and the plurality of pipes42constitute a single member, and there is no gap between the plate-shaped member1331and each of the pipes42. That is, the adapter133is configured to include a seal structure.

Five pipes42are attached to the adapter133. The five pipes42are arranged in the left-right direction. A rightmost pipe42ais a pipe through which air flows. Second and third pipes42band42cfrom the right are pipes through which a coolant (first coolant) for the fuel cell stack2aincluded in the fuel cell module2flows. Fourth and fifth pipes42dand42efrom the right are pipes through which a coolant (second coolant) for power electronic devices including a boost converter included in the fuel cell module2flows.

FIG.4Billustrates a structure for attaching the adapter133illustrated inFIG.4Ato the partition wall13. As illustrated inFIG.4B, the adapter133is disposed so as to close one through hole131A provided in the partition wall13. Thus, the plurality of pipes42are disposed across the first section11and the second section12through the through hole131A. A seal member1321constituting a seal structure132A is disposed between the adapter133and the partition wall13. Further, as described above, the adapter133itself is configured to include the seal structure. Therefore, it is possible to prevent hydrogen from flowing into the second section12from the first section11.

In the first section11and the second section12, corresponding pipes are coupled to both end portions in the up-down direction of each pipe42included in the adapter133in a sealed state.

As illustrated inFIG.2, a hydrogen flow passage5(thick solid line) is disposed in the first section11. In other words, the fuel cell system100includes the hydrogen flow passage5disposed in the housing1. Specifically, the hydrogen flow passage5includes a hydrogen supply passage51that supplies hydrogen to the fuel cell module2. Further, the hydrogen flow passage5includes a vent passage52that discharges hydrogen from the fuel cell module2. The hydrogen flow passage5can be formed by coupling a plurality of pipes. There is a possibility that hydrogen leaks from a coupling part between the pipes. In consideration of this point, the first section11is provided with a hydrogen leakage countermeasure.

The housing1has a connection part6(seeFIG.1) between the hydrogen flow passage5and an external hydrogen flow passage200disposed outside the housing1, on a wall different from the partition wall13among the walls11ato11eand13constituting the first section11. The connection part6may be a connection portion itself for connecting the hydrogen flow passage5and the external hydrogen flow passage200, or may be a means for implementing the connection between them. In the present embodiment, the connection part6is an opening for exposing or disposing the end portion of the hydrogen flow passage5disposed in the first section11to the outside of the housing1. The hydrogen flow passage5and the external hydrogen flow passage200can be connected to each other by using the opening. Specifically, the connection is a connection between pipes.

In the present embodiment, the connection part6is provided on the first section right wall11d.However, the connection part6may be provided on a wall constituting the first section11other than the partition wall13, such as the first section left wall11c.The connection part6is provided on a wall other than the partition wall13constituting the first section11, and thus the hydrogen flow passage5can be configured not to be disposed in the second section12. That is, in the second section12, it is not necessary to take measures against hydrogen leakage. As a result, it is possible to easily take measures against hydrogen leakage in the fuel cell system100.

Similarly to the hydrogen flow passage5disposed inside the housing1, the external hydrogen flow passage200also includes an external hydrogen supply passage201, which is a passage for supplying hydrogen, and an external vent passage202, which is a passage for exhausting hydrogen. Correspondingly, the connection part6also has a hydrogen-supplying connection part61for connecting the hydrogen supply passage51and the external hydrogen supply passage201, and a vent connection part62for connecting the vent passage52and the external vent passage202(seeFIG.1). In the present embodiment, the hydrogen-supplying connection part61and the vent connection part62are provided on the same wall (first section right wall11d) constituting the first section11. However, this is merely an example, and the hydrogen-supplying connection part61and the vent connection part62may be provided on different walls constituting the first section11.

In the present embodiment, a plurality of fuel cell modules2are disposed in the first section11. The plurality of fuel cell modules2are arranged side by side in the left-right direction. Specifically, the number of the fuel cell modules2disposed in the first section11is four. The hydrogen that has entered the hydrogen supply passage51in the housing1from the external hydrogen supply passage201reaches a branch part56that branches the hydrogen supply passage51into four, through a valve device53. At the branch part56, the hydrogen is distributed to four hydrogen supply passages51provided exclusively for the respective fuel cell modules2. Then, the distributed hydrogen is supplied to the respective fuel cell modules2.

As can be seen from the above description, the number of the hydrogen supply passages51in the first section11which are connected to the external hydrogen supply passage201by using the connection part6is one. That is, in the present embodiment, at the position where the connection part6is provided, the hydrogen supply passage51in the first section11is not provided for each of the plurality of fuel cell modules2, but is shared among the plurality of fuel cell modules2. By performing such sharing, the number of the connection parts6can be reduced. Further, since the number of the connection parts6is reduced, it is possible to improve the sealing property of the first section11.

The valve device53includes a shutoff valve that shuts off the supply of hydrogen to the fuel cell module2. Further, the valve device53includes a bleed valve that releases hydrogen to the vent passage52when the supply of hydrogen to the fuel cell module2is shut off. In the present embodiment, in the first section11, the valve device53is disposed between a wall (first section right wall11d) on which the connection part6is provided and the fuel cell module2. Specifically, the valve device53is disposed between the first section right wall11dand the fuel cell module2in the left-right direction. The valve device53is disposed at such a position, and therefore the connection part6can be disposed at a position away from the fuel cell module2. Pipes through which hydrogen flows are connected to each other at the connection part6or in the vicinity thereof, and therefore the possibility of hydrogen leakage is likely to be higher than in other portions. In this regard, in the present embodiment, the connection part6is disposed at a position away from the fuel cell module2, and therefore it is possible to reduce the possibility that the leaked hydrogen reaches the fuel cell module2. That is, safety can be improved.

The vent passage52includes a shared vent passage521shared among the plurality of fuel cell modules2. The hydrogen discharged from each fuel cell module2is sent to the shared vent passage521. With this configuration, the number of the vent connection parts62connecting the vent passage52and the external vent passage202can be minimized. In the present embodiment, the shared vent passage521is provided, and therefore the number of the vent connection parts62is one. The vent connection part62is an opening for exposing or disposing the end portion of the shared vent passage52to the outside of the housing1. It should be noted that the configuration described above is merely a preferred configuration, and a configuration may be employed in which a separate vent passage is provided for each fuel cell module2, and the gas is separately discharged to the outside of the housing1.

FIG.5is a schematic diagram for explaining a variation of the vent passage52. As illustrated inFIG.5, the fuel cell system100may include a drain part57connected to the vent passage52. Specifically, the drain part57includes a drain passage connected to the vent passage52, and a drain valve that discharges drain water. By providing the drain part57, the condensed water generated in the vent passage52can be prevented from flowing back to the fuel cell stack2aof the fuel cell module2. As a result, the occurrence of a failure in the fuel cell system100can be reduced.

In the example illustrated inFIG.5, the drain part57is provided outside the housing1. However, the drain part57may be provided inside the housing1. Further, the number of the drain part57connected to the vent passage52may be one or more. The drain part57may be provided not only at the end portion of the vent passage52but also at the intermediate portion of the vent passage52.

As described above, the hydrogen flow passage5configured by coupling a plurality of pipes is disposed in the first section11, and thus there is a possibility that hydrogen leaks. For this reason, the first section11is provided with a configuration that enables ventilation as a countermeasure against hydrogen leakage. The first section11is provided with an intake port111and an exhaust port112for ventilation (seeFIGS.1and2). The ventilation may be interpreted as a term indicating replacement of air, but may be interpreted as a term indicating replacement of inert gas such as nitrogen gas or argon gas. In this connection, it may be provided that the first section11can be filled with an inert gas. With such a configuration, when hydrogen leaks from the first section11, the possibility that the leaked hydrogen reacts with oxygen in the first section11can be reduced.

The intake port111may be provided in at least one of the walls11ato11eand13constituting the first section11except for the partition wall13. In the present embodiment, the intake port111is provided on the first section right wall11d.The intake port111provided in the first section right wall11dis a through hole penetrating the wall in the left-right direction. A ventilation fluid (for example, air, nitrogen gas, argon gas, or the like) is supplied into the first section11from the intake port111. A pipe for supplying the ventilation fluid is attached to the intake port111.

In the present embodiment, the opening constituting the connection part6has a function as an inlet of the ventilation fluid. That is, the opening constituting the connection part6has a function as an intake port. A configuration relating to this will be described by taking a case where the connection part6is the hydrogen-supplying connection part61as an example. Although not described, the same configuration may be employed in a case where the connection part6is the vent connection part62.

FIG.6is a diagram illustrating a schematic configuration around the hydrogen-supplying connection part61included in the fuel cell system100according to the embodiment of the present invention. The hydrogen-supplying connection part61is an opening AP, and a pipe51P constituting the hydrogen supply passage51and a pipe201P constituting the external hydrogen supply passage201are connected to each other with the use of the opening AP. In a state where the two pipes51P and201P are connected to each other, the opening AP constituting the hydrogen-supplying connection part61is not entirely closed, and the inside of the first section11communicates with the outside of the housing1through the opening AP.

Around the pipe201P constituting the external hydrogen supply passage201, an outer pipe203is disposed to surround the pipe201P. In other words, the pipe201P constituting the external hydrogen supply passage201is disposed inside the outer pipe203. In the following description ofFIG.6, the pipe201P constituting the external hydrogen supply passage201will be referred to as an inner pipe201P.

The housing1is provided so that the outer pipe203surrounding an outer periphery of the inner pipe201P constituting the external hydrogen flow passage200(for example, the external hydrogen supply passage201) can be attached thereto. The outer pipe203is attached to the housing1by using, for example, a screw. The outer pipe203surrounds the opening AP constituting the hydrogen-supplying connection part61. The inner diameter of the outer pipe203is larger than the diameter of the opening AP. An internal space204formed between the inner pipe201P and the outer pipe203communicates with the inside of the first section11through the opening AP. The ventilation fluid can flow through the internal space204. That is, the first section11is provided so as to be able to supply the ventilation fluid via the internal space204between the inner pipe201P and the outer pipe203.

The ventilation fluid can be supplied into the first section11by using the internal space204, and therefore the size of the intake port111described above can be reduced. In some cases, the intake port111may not be provided. Further, even when hydrogen leaks from the inner pipe201P, the leaked hydrogen can be sent from the internal space204into the first section11together with the ventilation fluid, and can be safely discharged to the outside. The discharge of ventilation fluid from the first section11will be described below.

As illustrated inFIG.6, a hydrogen concentration detection device50is preferably disposed in the vicinity of the connection part6in the first section11. The vicinity of the connection part6is specifically a hydrogen leakage detection range. With such a configuration, it is possible to quickly detect the hydrogen leakage from the connection portion between the two pipes51P and201P or the inner pipe201P. The operation of the fuel cell system100can be promptly stopped by promptly detecting the hydrogen leakage.

The first section11has a ventilation device that ventilates the inside of the section or a ventilation device connection part connected to the ventilation device. In the present embodiment, as illustrated inFIGS.1and2, the first section11has a ventilation device connection part113connected to a ventilation device300. The ventilation device connection part113includes an exhaust port112. The ventilation device300is disposed on the downstream side of the flow of the ventilation fluid with respect to the exhaust port112. The ventilation device300discharges the ventilation fluid to an area excluding the second section12. When the ventilation device300is driven, the fluid in the first section11is discharged to the outside of the first section11through the exhaust port112. Even when hydrogen leaks in the first section11, the hydrogen can be discharged to the outside of the housing1together with the ventilation fluid in such manner that the hydrogen does not leak into the second section12.

Specifically, the exhaust port112is provided in the first section upper wall11e(upper surface wall1eof the housing1). That is, the ventilation device connection part113is provided on the first section upper wall11ewhich is the upper wall of the first section11. Even when hydrogen leaks, it is only necessary to guide the hydrogen above the fuel cell module2, making it easier to discharge hydrogen.

In a case where the first section11is configured to include the ventilation device300, the ventilation device300may be disposed on the downstream side of the flow of the ventilation fluid with respect to the exhaust port112. Also in this case, the ventilation device300is preferably provided on the first section upper wall11e,which is the upper wall of the first section11.

In the first section11, measures are taken to facilitate discharge of the leaked hydrogen from the exhaust port112.FIG.7is a schematic diagram illustrating a configuration example of the hydrogen flow passage5disposed in the first section11. As illustrated inFIG.7, a pipe coupling part54is provided in the first section11to couple the pipes5P constituting the hydrogen flow passage5.

In the present embodiment, the pipe coupling part54includes an upper pipe coupling part541disposed above the fuel cell module2. Although there is a possibility that hydrogen leaks from the pipe coupling part54, the upper pipe coupling part541can prevent the leaked hydrogen from flowing toward the fuel cell module2. That is, safety can be improved.

In a case where a plurality of pipe coupling parts54are provided in the fuel cell system100, all of the pipe coupling parts54are preferably the upper pipe coupling parts541. However, at least some of the plurality of pipe coupling parts54may not be the upper pipe coupling part541.

The fuel cell system100includes a cover member that covers at least a part of the pipe coupling part54. With the configuration in which the cover member is provided, in a case where hydrogen having high diffusibility leaks from the pipe coupling part54, diffusion of hydrogen in the first section11can be suppressed. In the example illustrated inFIG.7, a plate-shaped member55disposed below the pipe coupling part54that couples the two pipes5P extending in the left-right direction to each other corresponds to the cover member that covers a part of the pipe coupling part54. The plate-shaped member55(cover member) disposed below the pipe coupling part54can prevent the leaked hydrogen from diffusing toward the fuel cell module2, and can suppress the leaked hydrogen from remaining behind the components.

FIGS.8A and8Bare diagrams for explaining a cover member55A according to a variation.FIG.8Ais a side view, and a one-dot chain line indicates an internal structure.FIG.8Bis a top view. In the variation, the two pipes5P to be coupled extend vertically. The pipe coupling part54includes a flange portion5F provided at the lower end of the upper pipe5P and a flange portion5F provided at the upper end of the lower pipe5P. The cover member55A has a vertically extending tubular shape and is disposed around the pipe coupling part54. The cover member55A covers the entire periphery of the pipe coupling part54. A plurality of claw portions551protruding inward are provided inside the cylindrical cover member55A. The claw portions551are caught by the pipe coupling part54, and the cover member55A is supported by the pipe coupling part54. Even in such a configuration, the diffusion of the leaked hydrogen can be prevented.

In addition, an exhaust passage7and a reserve tank8are disposed in the first section11(seeFIG.2). InFIG.2, the exhaust passage7is indicated by a thin two-dot chain line.

The exhaust passage7is connected to the fuel cell module2. Specifically, the exhaust passage7is an exhaust pipe. The exhaust passage7is used for circulation of exhaust gas of the fuel cell module2. The exhaust gas includes, for example, water vapor generated during power generation, oxygen and nitrogen that have been supplied to the fuel cell module2but have not been used, and hydrogen that is purged and discharged from the anode path of the fuel cell stack2aas appropriate. In the present embodiment, a separate exhaust passage7is connected to each of the four fuel cell modules2disposed in the first section11. That is, four exhaust passages7are disposed in the first section11. The four exhaust passages7are coupled to an exhaust passage collection part71disposed in the first section11. The exhaust passage collection part71is disposed at a right end portion of the first section11. The exhaust gas in the four exhaust passages7is collected in the exhaust passage collection part71and is discharged to the outside of the first section11through one terminal exhaust passage72(seeFIG.1). The exhaust passage collection part71may be provided outside the first section11. Alternatively, the outlet of each exhaust passage7may be directly connected to an external exhaust passage outside the first section11without providing the exhaust passage collection part71.

As illustrated inFIG.1, the distal end (right end) of the terminal exhaust passage72protrudes outward from the first section right wall11d.An external exhaust passage (not illustrated) is connected to the distal end of the terminal exhaust passage72, and discharges exhaust gas in the fuel cell module2to an appropriate place.

FIG.9is a schematic diagram illustrating a relation between the fuel cell module2and the exhaust passage7. As illustrated inFIG.9, the exhaust passage7includes a flow passage that guides the exhaust gas downward from the fuel cell module2. The flow passage that guides the exhaust gas downward is obtained by forming a portion7aextending downward in the exhaust passage7. The portion7aextending downward is not necessarily parallel to the up-down direction, and may be inclined with respect to the up-down direction. By providing the flow passage that guides the exhaust gas downward, the condensed water generated in the exhaust passage7can be prevented from flowing back to the fuel cell stack2a.That is, the occurrence of a failure in the fuel cell system100can be suppressed.

The reserve tank8is included in a cooling system CS provided for the fuel cell module2(seeFIG.2). Specifically, the cooling system CS provided for the fuel cell module2includes a first cooling system CS1and a second cooling system CS2. Therefore, in particular, the reserve tank8includes a first reserve tank81included in the first cooling system CS1and a second reserve tank82included in the second cooling system CS2.

The first cooling system CS1is a cooling system that cools the fuel cell stack2aof in the fuel cell module2. That is, the reserve tank81included in the cooling system CS1that cools the fuel cell stack2aof the fuel cell module2is disposed in the first section11. The first cooling system CS1circulates a first coolant that cools the fuel cell stack2aby driving a pump (not illustrated) included in the fuel cell module2. The pump described above may be disposed outside the fuel cell module2. The first reserve tank81stores or discharges the first coolant as necessary.

The first reserve tank81is disposed above the fuel cell stack2a.Therefore, even when the first coolant contains hydrogen due to a malfunction, the hydrogen can be released to a position higher than the fuel cell stack2a.The first cooling system CS1is provided for each of the fuel cell modules2. To this end, in the present embodiment, four first reserve tanks81are disposed in the first section11.

As illustrated inFIG.2, each of the first reserve tanks81is connected to an air vent pipe811(thin solid line). Further, as illustrated inFIG.1, an end portion of the air vent pipe811is exposed to the outside through an opening (not illustrated) in the first section right wall11d.Even when hydrogen is contained in the first coolant due to a malfunction, the hydrogen can be discharged to the outside of the first section11through the air vent pipe811.

The second cooling system CS2is a cooling system that cools a power electronic device included in the fuel cell module2. That is, the reserve tank82included in the cooling system CS2that cools the power electronic device of the fuel cell module2is disposed in the first section11. The second cooling system CS2circulates a second coolant that cools the power electronic device by driving a pump (not illustrated) included in the fuel cell module2. The pump described above may be disposed outside the fuel cell module2. The second reserve tank82stores or discharges the second coolant as necessary.

The second cooling system CS2is provided for each of the fuel cell modules2. To this end, in the present embodiment, four second reserve tanks82are disposed in the first section11.

As described above, auxiliary machines relating to the operation of the fuel cell module2is disposed in the second section12. The auxiliary machines include at least one of a switchboard, an air intake unit that takes air into the fuel cell module2, and a heat exchanger through which a coolant that cools components included in the fuel cell module2flows.

As illustrated inFIG.2, in the present embodiment, the auxiliary machines include an air intake unit9, a heat exchanger10, and a switchboard20. That is, the fuel cell system100includes the air intake unit9, the heat exchanger10, and the switchboard20. The housing1houses the air intake unit9, the heat exchanger10, and the switchboard20.

Specifically, the air intake unit9takes in air to be supplied to the air electrode of the fuel cell stack2a.In the present embodiment, the air intake unit9is disposed in the second section12. That is, the air intake unit9is disposed in a section where hydrogen does not leak. Therefore, it is possible to prevent a situation where air containing hydrogen is taken in from the air intake unit9. As a result, the air containing hydrogen can be prevented from being supplied to the air electrode of the fuel cell stack.

Specifically, in the second section12, the same number of air intake units9as the plurality of fuel cell modules2disposed in the first section11are disposed. In the present embodiment, the number of fuel cell modules2is four, and the number of air intake units9is also four. In the present embodiment, the air intake unit9is not shared by the plurality of fuel cell modules2, but the air intake unit9is provided for each fuel cell module2. Therefore, when a malfunction occurs in any of the plurality of fuel cell modules2, it is not necessary to stop all the fuel cell modules2, and the fuel cell module2in which a malfunction does not occur can be continuously operated.

Specifically, the air intake unit9includes a filter. An air pipe421(indicated by a thick two-dot chain line inFIG.2) through which air flows is connected to the air intake unit9. The air pipe421is configured to include a pipe42aprovided in the adapter133(seeFIG.4A) and is disposed across the first section11and the second section12. When the compressor included in the fuel cell module2operates, the air taken in from the air intake unit9is supplied to the air electrode of the fuel cell stack2aincluded in the fuel cell module2.

In the present embodiment, the heat exchanger10is disposed in the second section12. The heat exchanger10having a large volume is disposed in the second section12, and thus an increase in the volume of the first section11can be suppressed. By suppressing an increase in the volume of the first section11, an increase in the size of the ventilation device300can be suppressed.

The heat exchanger10constitutes the cooling system CS provided for the fuel cell module2. As described above, in the present embodiment, the cooling system CS includes the first cooling system CS and the second cooling system CS. To this end, in particular, the heat exchanger10includes a first heat exchanger101constituting the first cooling system CS1and a second heat exchanger102constituting the second cooling system CS2. The first heat exchanger101and the second heat exchanger102are provided for each fuel cell module2. That is, four first heat exchangers101and four second heat exchangers102are disposed in the second section12.

The first heat exchanger101exchanges heat between the first coolant and a third coolant supplied from the outside of the housing1.

The first coolant is sent from the fuel cell stack2ato the first heat exchanger101and is returned from the first heat exchanger101to the fuel cell stack2aby using a first coolant pipe422that connects the first heat exchanger101and a pump included in the fuel cell module2. The first coolant pipe422is configured to include pipes42band42cprovided in the adapter133(seeFIG.4A) and is disposed across the first section11and the second section12. The first coolant pipe422is indicated by a one-dot chain line inFIG.2.

The third coolant is supplied from the outside of the housing1to the first heat exchanger101and discharged from the first heat exchanger101to the outside of the housing1by using a third coolant pipe424disposed in the second section12. As illustrated inFIG.1, the second section right wall12dis provided with a connection port121for connecting the third coolant pipe424for supplying and discharging the third coolant with an external pipe. A device disposed outside the housing1is used to supply the third coolant to the third coolant pipe424. The third coolant may be, but is not limited to, seawater. The third coolant pipe424is indicated by a thick one-dot chain line inFIG.2.

The second heat exchanger102exchanges heat between the second coolant and the third coolant supplied from the outside of the housing1. The equipment for supplying and discharging the third coolant is shared with the first heat exchanger101.

The second coolant is sent from the power electronic device to the second heat exchanger102and is returned from the second heat exchanger102to the power electronic device by using a second coolant pipe423that connects the second heat exchanger102and a pump included in the fuel cell module2. The second coolant pipe423is configured to include pipes42dand42eprovided in the adapter133(seeFIG.4A) and is disposed across the first section11and the second section12. The second coolant pipe423is indicated by a thin one-dot chain line inFIG.2.

The third coolant is supplied from the outside of the housing1to the second heat exchanger102and discharged from the second heat exchanger102to the outside of the housing1by using the third coolant pipe424disposed in the second section12.

In the present embodiment, the switchboard20is disposed in the second section12. That is, the switchboard20is disposed in a section where hydrogen does not leak. Even if hydrogen leaks in the first section11, the leaked hydrogen can be prevented from coming into contact with the switchboard20. Specifically, the switchboard20is disposed at a right end portion of the second section12. The second section right wall12dis provided with an electric wire arrangement part122in which wires connected to the switchboard20are arranged. Specifically, the electric wire arrangement part122is a portion through which an electric wire is taken out from the inside of the housing1to the outside and an electric wire is inserted from the outside to the inside. Further, the electric wire arrangement part122may be a portion that connects an electric wire inside the housing1and an electric wire outside the housing1. The electric wire arrangement part122may be configured by an opening through which an electric wire passes, a connector to which an electric wire is connected, or the like.

The switchboard20includes various terminals and relays. The various terminals include, for example, a terminal connected to a power line411(thick broken line inFIG.2) through which electric power generated by the fuel cell module2flows. The power line411is included in the wires41(seeFIG.3) disposed across the first section11and the second section12. Further, the various terminals include a terminal connected to a control line412(thin broken line inFIG.2) that performs control with the fuel cell module2. The control line412is included in the wires41(seeFIG.3) disposed across the first section11and the second section12. In addition, the various terminals include terminals connected to sensor lines connected to sensors such as a pressure sensor and a temperature sensor. Further, the various terminals include a terminal connected to a communication line for communicating with an external control device.

The external control device is a control device that controls the fuel cell system100. In the present embodiment, the control device is disposed outside the housing1. However, the control device may be disposed in the switchboard20. The control device disposed in the switchboard20may be remotely controlled from the outside.

FIG.10is a schematic horizontal cross-sectional view of the fuel cell system100taken along line A-A illustrated inFIG.1. As illustrated inFIG.10, in the present embodiment, the desalination device3is installed on the second section front wall12a.However, the desalination device3may be provided on a wall other than the partition wall13among the walls12ato12eand13constituting the second section12.

The desalination device3comprises a desalination filter3a. Specifically, the desalination filter3ahas a rectangular plate shape. As illustrated inFIG.1, the second section front wall12ais provided with a window part123that allows air to be taken into the second section12through the desalination filter3a.Air is taken into the second section12through the window part123and the desalination filter3a.Air from which salinity has been removed by the desalination filter3ais taken into the second section12.

Specifically, the fuel cell system100is provided with a plurality of desalination devices3. The number of the desalination devices3may be one, but the load of each desalination device3can be reduced by arranging a plurality of desalination devices3. As a result, the maintenance interval of the desalination device3can be prolonged, the replacement frequency of the desalination filter3acan be reduced, and the pressure loss of the air passing through the desalination device3can be reduced. More specifically, four desalination devices3are arranged side by side in the left-right direction. Four window parts123provided in the second section front wall12aare also arranged side by side in the left-right direction. As in the present embodiment, the plurality of desalination devices3are preferably disposed on the same side surface of the housing1, but in some cases, the plurality of desalination devices3may be disposed on different side surfaces of the housing1.

In the second section12, at least one of an auxiliary machine relating to the operation of the fuel cell module2and a pipe is disposed between the desalination filter3aand the air intake unit9. As illustrated inFIG.10, in the present embodiment, an auxiliary machine and the pipe42are disposed between the desalination filter3aand the air intake unit9. The auxiliary machine disposed between both the desalination filter3aand the air intake unit9is a heat exchanger10. Specifically, the auxiliary machine disposed between the desalination filter3aand the air intake unit9is the box-shaped first heat exchanger101and the box-shaped second heat exchanger102. As a preferred embodiment, when the housing1is viewed from the front (when viewed from the front-rear direction), the desalination filter3aand the heat exchanger10are disposed at positions overlapping each other.

The auxiliary machine10and the pipe42are disposed between the desalination filter3aand the air intake unit9, and it is thereby possible to suppress the air that has passed through the desalination filter3afrom moving linearly toward the air intake unit9. In this case, it is possible to suppress the passage of the air in the desalination filter3afrom being concentrated on a part, and thus it is possible to suppress the desalination filter3afrom being locally clogged. Further, the box-shaped heat exchanger10is disposed between the desalination filter3aand the air intake unit9, and it is thereby possible to enhance the effect of suppressing the air that has passed through the desalination filter3afrom moving linearly toward the air intake unit9.

Further, as illustrated inFIG.10, an electrical component30is disposed in the second section12. The electrical component30is, for example, a relay. The electrical component30is disposed further rearward of the air intake unit9disposed rearward of the desalination device3. The main flow of the air in the second section12is a flow from the desalination device3to the air intake unit9. In the configuration in which the electrical component30is disposed further rearward of the air intake unit9, the electrical component30is out of the mainstream of the air flow. Therefore, even when the salinity is not completely removed by the desalination device3, it is possible to reduce the possibility of salt damage to the electrical component30.

Even when the salinity is not sufficiently removed by the desalination device3, air having a sufficiently reduced salinity is supplied to the fuel cell module2because the air intake unit9includes a filter.

FIG.11is a front view illustrating a schematic configuration of a right end side of the second section12. InFIG.11, the right end portion of the second section12is exposed by removing a part of the front surface wall1aof the housing1for convenience. As illustrated inFIGS.10and11, in a front view from the front surface wall1a(first outer surface wall) of the housing1, the switchboard20offset to one side in the left-right direction with respect to the desalination device3and the air intake unit9is disposed in the second section12. Specifically, the switchboard20is offset to the right with respect to the desalination device3and the air intake unit9. More specifically, the switchboard20is offset to the right with respect to the rightmost one of the four desalination devices3and the rightmost one of the four air intake units9.

With such a configuration, the switchboard20can be disposed at a position away from the flow of air from the desalination device3toward the air intake unit9. Therefore, it is possible to reduce the possibility that the switchboard20is damaged by salt due to a small amount of salt that has not been removed by the desalination device3.

As can be seen from the above, the housing1has a first outer surface wall (the front surface wall1ain a detailed example) on which the desalination device3located upstream of the air intake unit9in the flow of air is disposed (see, for example,FIG.1). In addition, the housing1has a second outer surface wall (the right surface wall1din a detailed example) provided with the electric wire arrangement part122in which wires are arranged. The electric wire taken out from the electric wire arrangement part122to the outside of the housing1is connected to an external control device or an external power using component.

In the periphery of the housing1, the flow rate of the air passing through the periphery of the desalination device3is likely to be larger than the flow rate of the air passing through outside the periphery of the desalination device3, although depending on the installation location. For this reason, the progress of salt damage tends to be faster in the periphery of the desalination device3than outside the periphery of the desalination device3. In the present embodiment, the electric wire arrangement part122is provided on an outer surface wall (right surface wall1d) of the housing1different from the outer surface wall (front surface wall1a) on which the desalination device3is provided. For this reason, the electric wire arrangement part122is positioned in a portion where the flow of air around the housing is small. As a result, the electric wire taken out from the electric wire arrangement part122to the outside of the housing1can be arranged at a position where the salt concentration is relatively low, and the possibility that the electric wire is damaged by salt can be reduced.

In the present embodiment, the second outer surface wall (right surface wall1d) of the housing1is provided with the connection part6that connects the hydrogen flow passage5and the external hydrogen flow passage200disposed outside the housing1. That is, in the present embodiment, external pipes and external wires connected to the fuel cell system100can be collected on one outer surface wall of the housing1.

Specifically, on the second outer surface wall (right surface wall1d) of the housing1, the electric wire arrangement part122is disposed below the connection part6. As a result, the connection part6and the electric wire arrangement part122can be provided on walls constituting different sections. Specifically, the connection part6may be provided on a wall constituting the first section11of the second outer surface wall, and the electric wire arrangement part122may be provided on a wall constituting the second section12of the second outer surface wall. As a result, it is possible to form the fuel cell system100in which measures against hydrogen leakage are appropriately taken, without complicating the structure.

In the present embodiment, the first outer surface wall (front surface wall1a) on which the desalination device3is disposed has a detachable wall which is detachable.FIG.12is a view illustrating a state where a part of a detachable wall is detached from the fuel cell system100illustrated inFIG.1. As illustrated inFIG.12, the detachable wall includes a first section detachable wall110and a second section detachable wall120.

The second section detachable wall120is a wall constituting the second section12. That is, the first outer surface wall (front surface wall1a) is a wall constituting the second section12, and is configured to include the second section detachable wall120which is detachable. In the configuration of the present embodiment in which the first outer surface wall is the front surface wall1a,the second section detachable wall120may be the second section front wall12aitself, or may be a part of the second section front wall12a. In the present embodiment, the second section detachable wall120is a part of the second section front wall12a.

Specifically, the second section front wall12aincludes a plurality of second section detachable walls120. More specifically, the second section front wall12aincludes four second section detachable walls120. The plurality of second section detachable walls120are arranged in the left-right direction. In the example illustrated inFIG.12, the second section detachable wall120which is the third from left to right is detached. The second section detachable wall120is detachably attached to the housing1by using, for example, a screw, but may be attached to the housing1by other detachable means.

In the present embodiment, the desalination device3is attached to the second section detachable wall120. The second section detachable wall120is provided with the window part123that allows air to be taken into the second section12through the desalination filter3a.The desalination device3is attached to the second section detachable wall120, and thus the desalination device3can be taken out from the second section12by detaching the second section detachable wall120. That is, the maintenance of the desalination device3can be facilitated.

The first section detachable wall110is a wall constituting the first section11. That is, the first outer surface wall (front surface wall1a) is a wall constituting the first section11, and is configured to include the first section detachable wall110which is detachable. In the configuration of the present embodiment in which the first outer surface wall is the front surface wall1a,the first section detachable wall110may be the first section front wall11aitself, or may be a part of the first section front wall11a.In the present embodiment, the first section detachable wall110is a part of the first section front wall11a.

Specifically, the first section front wall11aincludes a plurality of first section detachable walls110. More specifically, the first section front wall11aincludes five first section detachable walls110. The plurality of first section detachable walls110are arranged in the left-right direction. In the example illustrated inFIG.12, the first section detachable wall110which is the third from left to right is detached. The first section detachable wall110is detachably attached to the housing1by using, for example, a screw, but may be attached to the housing1by other detachable means. Further, the first section detachable wall110is sealed in a state of being attached to the housing1in such a manner that the hydrogen gas does not leak from the first section11.

By providing the first section detachable wall110, it is possible to facilitate maintenance in the first section11. Further, since the first section detachable wall110is provided separately from the second section detachable wall120, only the first section11can be inspected separately from the second section12. If the first section11needs to be inspected during the operation of the fuel cell system100, the inspection can be performed by detaching only the first section detachable wall110without detaching the second section detachable wall120. Therefore, it is possible to prevent the air containing salt from being supplied from the air intake unit9to the fuel cell module2.

3. Installation Section of Fuel Cell System

Next, an installation section of the fuel cell system100having the housing1in which the fuel cell module2and the desalination device3are disposed will be described.FIG.13is a perspective view illustrating a schematic configuration of a fuel cell system installation section400according to the embodiment of the present invention. As illustrated inFIG.13, the fuel cell system installation section400includes a floor surface401and a vertical wall402.

The housing1is disposed on the floor surface401. In particular, the floor surface401is horizontal. The housing1is disposed in the fuel cell system installation section400with the bottom surface wall1ffacing the floor surface401. The vertical wall402extends upward from the floor surface401. In the present embodiment, the floor surface401and the vertical wall402are orthogonal to each other.

The housing1includes the first outer surface wall, the second outer second outer surface wall, and a third outer surface wall. In the present embodiment, the first outer surface wall is the front surface wall1aon which the desalination device3is disposed. The second outer surface wall is the right surface wall1dprovided with the electric wire arrangement part122in which a wire is arranged. The third outer surface wall is the rear surface wall1bfacing the front surface wall1awhich is the first outer surface wall.

The rear surface wall1b,which is the third outer surface wall, is disposed along the vertical wall402. Specifically, the rear surface wall1bis parallel to the vertical wall402and faces the vertical wall402. The rear surface wall1bis disposed close to the vertical wall402. Further, the right surface wall1d,which is the second outer second outer surface wall, is disposed in a direction orthogonal to the floor surface401and the vertical wall402.

With such a configuration, in the housing1, the wall (front surface wall1a) on which the desalination device3is disposed is disposed on the side opposite to the side on which the vertical wall402is present. Therefore, the air can be appropriately supplied to the air intake unit9without being obstructed by the wall. Further, since the electric wire arrangement part122is disposed on a surface different from the surface on which the desalination device3is disposed, it is possible to make the electric wires less susceptible to salt damage.

The second outer surface wall on which the electric wire arrangement part122is provided may be the left surface wall1cof the housing1. In this case, an external pipe for supplying and exhausting the hydrogen, an external pipe for exhausting the water-containing gas generated in the fuel cell module2, and an external pipe for supplying the coolant may be disposed on the left surface wall1cside. In this case, the disposition of the valve device53and the switchboard20disposed in the housing1may be changed from the right end portion to the left end portion, and the configuration of the pipes and wires in the housing1may be appropriately changed in accordance with this.

Further, in the configuration illustrated inFIG.13, the left surface wall1cof the housing1may extend upward from the floor surface401, and may be disposed close to another vertical wall403that forms a corner together with the vertical wall402.

The various technical features disclosed in the present specification can be modified in various ways without departing from the gist of the technical creation thereof. In addition, the multiple embodiments and variations described in the present specification may be combined to the extent possible.

5. Supplementary Notes

An exemplary fuel cell system of the present invention may have a configuration (first configuration) which includes a fuel cell module, an air intake unit that takes air into the fuel cell module, and a housing that houses the fuel cell module and the air intake unit, and in which the housing has a first outer surface wall on which a desalination device is disposed upstream of the air intake unit, and a second outer surface wall provided with an electric wire arrangement part on which an electric wire is arranged.

The fuel cell system having the above first configuration may have a configuration (second configuration) which includes a hydrogen flow passage disposed in the housing, and in which the second outer surface wall is provided with a connection part that connects the hydrogen flow passage and an external hydrogen flow passage disposed outside the housing.

The fuel cell system having the above second configuration may have a configuration (third configuration) in which the electric wire arrangement part is arranged below the connection part on the second outer surface wall.

In the fuel cell system having the above third configuration, a configuration (fourth configuration) may be employed in which the housing includes a first section in which the fuel cell module is disposed and a second section which is adjacent to the first section and in which the air intake unit is disposed, the connection part is provided in the first section, and the electric wire arrangement part is provided in the second section.

In the fuel cell system having any one of the above first to fourth configurations, a configuration (fifth configuration) may be employed in which the housing includes a first section in which the fuel cell module is disposed and a second section which is adjacent to the first section and in which the air intake unit is disposed, the first outer surface wall includes a second section detachable wall which is a wall constituting the second section and is detachable, and the desalination device is disposed in the second section detachable wall.

In the fuel cell system having the above fifth configuration, a configuration (sixth configuration) may be employed in which the first outer surface wall includes a first section detachable wall which is a wall constituting the first section and is detachable.

In the fuel cell system having the above fifth or sixth configuration, a configuration (seventh configuration) may be employed in which an electrical component is disposed in the second section, and the electrical component is disposed further rearward of the air intake unit disposed rearward of the desalination device.

In the fuel cell system having any one of the above fifth to seventh configurations, a configuration (eighth configuration) may be employed in which the desalination device includes a desalination filter, and at least one of an auxiliary machine relating to an operation of the fuel cell module and a pipe is disposed between the desalination filter and the air intake unit in the second section.

In the fuel cell system having the above eighth configuration, a configuration (ninth configuration) may be employed in which the auxiliary machine is a heat exchanger.

In the fuel cell system having any one of the above fifth to ninth configurations, a configuration (tenth configuration) may be employed in which, in a front view from the first outer surface wall side, a switchboard offset to one side in a left-right direction with respect to the desalination device and the air intake unit is disposed in the second section.

In the fuel cell system having any one of the above first to tenth configurations, a configuration (eleventh configuration) may be employed in which a plurality of the desalination devices are disposed.

An exemplary fuel cell system installation section of the present invention is a fuel cell system installation section for a fuel cell system having a housing in which a fuel cell module and a desalination device are disposed, and may have a configuration (twelfth configuration) which includes a floor surface on which the housing is disposed, and a vertical wall extending upward from the floor surface, and in which the housing includes a first outer surface wall on which the desalination device is disposed, a second outer surface wall provided with an electric wire arrangement part in which an electric wire is arranged, and a third outer surface wall facing the first outer surface wall, and in which the third outer surface wall is disposed along the vertical wall, and the second outer surface wall is disposed in a direction orthogonal to the floor surface and the vertical wall.

REFERENCE SIGNS LIST