JP6702174B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system.

  The fuel cell system is connected to a supply passage for sending an anode gas toward the fuel cell, a circulation passage for circulating the anode off gas discharged from the fuel cell to the fuel cell, and a supply passage and a circulation passage. , And a confluent flow path for sending the anode gas and the anode off gas toward the fuel cell.

JP, 2013-251178, A

  In the fuel cell system of Patent Document 1, the supply channel is connected to the confluent channel in the horizontal direction, and the circulation channel is connected to the confluent channel from the lower side in the gravity direction. In such a fuel cell system, the anode gas is sent from the horizontal direction toward the confluence channel, and the anode off-gas is sent from the lower side in the direction of gravity. For this reason, the anode gas and the anode off-gas may not be sufficiently mixed, and the gas may be sent to the fuel cell while being nonuniform in concentration. If the gas concentration is non-uniform, there is a single cell of which the gas concentration is insufficient among the plurality of single cells forming the fuel cell, which causes a decrease in cell voltage and catalyst deterioration. In order to solve such a problem, there has been a demand for a technique capable of preventing the gas concentration from being sent to the fuel cell while being nonuniform.

  The present invention has been made to solve at least a part of the problems described above, and can be realized as the following modes.

  (1) According to one aspect of the present invention, a fuel cell system is provided. This fuel cell system is a fuel cell system including a fuel cell and a tank for storing anode gas supplied to the fuel cell, which is connected to the tank and sends the anode gas toward the fuel cell. A supply flow path, a discharge flow path for sending an anode off gas discharged from the fuel cell, a circulation flow path connected to the discharge flow path for circulating the anode off gas to the fuel cell, the supply flow path and the A merging channel connected to a circulation channel and sending the anode gas and the anode off-gas toward the fuel cell, the supply channel being connected to the merging channel from a first direction, The circulation channel is connected to the merging channel from a second direction that is the opposite direction to the first direction, and the merging channel is located at a position where the supply channel is connected to the merging channel. From a certain first opening and a second opening located at a position where the circulation flow path is connected to the merging flow path, in a third direction orthogonal to the first direction and the second direction. And a positional relationship between the first opening and the second opening is such that when the flow path portion is cut by a plane perpendicular to the third direction, In the cross section, the first opening is arranged on the side of one region divided by a straight line extending along the first direction and the second direction through the center of the cross section, and the first opening is divided by the straight line. The second opening is arranged on the side of the other region formed, and the first opening and the second opening have a positional relationship of being arranged at a position overlapping the cross section. With such a configuration, a swirling flow is easily generated in the confluent flow path, so that the anode gas and the anode off gas are sufficiently mixed. As a result, the mixed gas has a uniform concentration, and thus it is possible to prevent the gas from being sent to the fuel cell while the concentration of the gas is uneven.

  (2) According to one aspect of the invention, a fuel cell system is provided. This fuel cell system is a fuel cell system including a fuel cell and a tank for storing the anode gas supplied to the fuel cell, which is connected to the tank and sends the anode gas toward the fuel cell. A supply flow path, a discharge flow path for sending anode off-gas discharged from the fuel cell, a circulation flow path connected to the discharge flow path for circulating the anode off-gas to the fuel cell, the supply flow path and the A merging passage connected to a circulation passage and sending the anode gas and the anode off-gas toward the fuel cell, the supply passage being connected to the merging passage from a first direction, The circulation channel is connected to the merging channel from a second direction that is the opposite direction to the first direction, and the merging channel is located at a position where the supply channel is connected to the merging channel. From a certain first opening and a second opening located at a position where the circulation flow path is connected to the merging flow path, in a third direction orthogonal to the first direction and the second direction. And a positional relationship between the first opening and the second opening is such that when the flow path portion is cut by a plane perpendicular to the third direction, In the cross section, the first opening and the second opening are provided on the side of one region divided by a straight line extending along the first direction and the second direction through the center of the cross section. The first opening portion and the second opening portion are arranged such that the first opening portion and the second opening portion are displaced from each other in the third direction. With such a configuration, the anode gas sent from the supply flow path and the anode off-gas sent from the circulation flow path generate a counter-rotating swirl flow in the merging flow path. Since the counter-rotating swirl flows are generated from the respective positions shifted in the third direction, turbulent flow that facilitates mixing of the anode gas and the anode off gas is likely to occur. As a result, since the mixed gas has a uniform concentration, it is possible to prevent the gas from being sent to the fuel cell while the concentration of the gas is nonuniform.

  The mode of the present invention is not limited to the fuel cell system, and may be applied to various modes such as a fuel cell system mounted on a vehicle and a ship that use electric power as a power source, the vehicle itself, the ship itself, and the like. It is possible. In addition, the present invention is not limited to the above-described embodiments, and it goes without saying that the present invention can be implemented in various forms without departing from the spirit of the present invention.

It is an explanatory view showing the composition of a fuel cell system. It is explanatory drawing which shows the positional relationship of a supply flow path, a circulation flow path, and a merging flow path. It is an explanatory view showing the composition of a fuel cell system. It is explanatory drawing which shows the positional relationship of a supply flow path and a merge flow path. It is explanatory drawing which shows the positional relationship of a circulation flow path and a merge flow path. It is an explanatory view showing the composition of a fuel cell system.

A. First embodiment:
FIG. 1 is an explanatory diagram showing a configuration of a fuel cell system 20 according to an embodiment of the present invention. In FIG. 1, XYZ axes that are orthogonal to each other are illustrated. The Z axis in the XYZ axes of FIG. 1 is a coordinate axis from the lower side to the upper side in the gravity direction. The XYZ axes in FIG. 1 correspond to the XYZ axes in the other figures. On the XYZ axes, the direction indicated by the arrow is the + side, and the direction opposite to the direction indicated by the arrow is the − side.

  The fuel cell system 20 is installed as a power source for a vehicle driven by a motor. The fuel cell system 20 includes a fuel cell stack 50 and an anode gas supply system 100. The fuel cell system 20 additionally includes a cathode gas supply system and an FC cooling system, but in the present embodiment, for ease of understanding, only the fuel cell stack 50 and the anode gas supply system 100 will be described. ..

  The fuel cell stack 50 is a unit that generates electricity by an electrochemical reaction between hydrogen and oxygen. The fuel cell stack 50 is formed by stacking a plurality of unit cells 55. The unit cell 55 is a power generation element capable of generating power even by a single unit, and is disposed on both outer sides of the membrane electrode assembly, which is a power generation body in which electrodes (cathode, anode) are disposed on both surfaces of the electrolyte membrane. And a separator that is formed. The electrolyte membrane is composed of a solid polymer thin film that exhibits good proton conductivity in a wet state in which water is contained. Various types can be applied to the fuel cell stack 50, but in the present embodiment, a solid polymer type is used.

  The anode gas supply system 100 has a function of supplying the anode gas to the fuel cell stack 50, a function of discharging the anode off gas discharged from the fuel cell stack 50 to the outside of the fuel cell system 20, and a function of discharging the anode off gas to the fuel cell system 20. It has a function of circulating the inside. The anode gas supply system 100 includes a hydrogen tank 110, a supply flow path 120, a discharge flow path 130, a gas-liquid separation section 140, a drain flow path 150, a circulation flow path 160, and a confluent flow path 170. ..

  The hydrogen tank 110 stores high-pressure hydrogen to be supplied to the fuel cell stack 50. In the present embodiment, the fuel cell stack 50 is supplied with hydrogen as the anode gas and oxygen as the cathode gas from the cathode gas supply system.

  The supply channel 120 is connected to the hydrogen tank 110. The supply flow path 120 is a flow path that sends the anode gas toward the fuel cell stack 50. The supply flow channel 120 is a flow channel including a portion extending along the Y-axis direction and a portion extending along the Z-axis direction. The supply flow path 120 has an opening/closing valve 125.

  The open/close valve 125 is a valve that can adjust the inflow amount of the anode gas into the fuel cell stack 50. The on-off valve 125 controls the inflow amount of the anode gas into the fuel cell stack 50 by being controlled by the ECU (not shown) to open and close.

  The discharge flow path 130 is connected to the fuel cell stack 50. The discharge flow path 130 is a flow path for sending the anode off gas discharged from the fuel cell stack 50. The discharge channel 130 is a channel that extends along the Y-axis direction. The discharge flow path 130 is connected to the gas-liquid separation section 140.

  The gas-liquid separation unit 140 separates the anode off-gas flowing through the discharge flow path 130 into a gas component and a liquid component. In the gas-liquid separator 140, the gas component of the anode off gas is guided to the circulation flow channel 160, and the liquid component of the anode off gas is guided to the drainage flow channel 150.

  The drainage flow path 150 is connected to the gas-liquid separation section 140. The drainage channel 150 is a channel for draining the liquid component of the anode off-gas separated by the gas-liquid separator 140 to the outside of the fuel cell system 20. The drainage channel 150 is a channel that extends along the Z-axis direction. The drainage channel 150 has a drainage valve 155.

  The drainage valve 155 is a valve that can adjust the opening and closing of the drainage flow path 150. The opening/closing of the drain valve 155 is controlled by an ECU (not shown). The drainage valve 155 opens the drainage flow path 150 at a preset drainage timing or an anode off-gas discharge timing.

  The circulation flow path 160 is connected to the discharge flow path 130 via the gas-liquid separation section 140. The circulation flow path 160 is a flow path for circulating the anode off gas in the fuel cell stack 50. The circulation channel 160 is a channel that extends along the Z-axis direction.

  The circulation channel 160 is connected to the merging channel 170 from the − side in the Z-axis direction. The supply channel 120 is connected to the merging channel 170 from the + side in the Z-axis direction. The position where the supply flow channel 120 and the circulation flow channel 160 are connected to the confluent flow channel 170 will be referred to as a connection position Cn1. The circulation flow path 160 has a circulation pump 165.

  The circulation pump 165 functions as a circulation pump that sends out the gas component of the anode off-gas separated in the gas-liquid separation unit 140 to the merging flow path 170. Since hydrogen is contained in the gas component of the anode off-gas, by operating the circulation pump 165, the hydrogen gas not consumed by the fuel cell stack 50 can be circulated to the fuel cell stack 50 again.

  The merging flow path 170 is connected to the connection position Cn from the + side in the Y-axis direction. The confluent flow passage 170 is a flow passage for sending the anode gas sent from the supply flow passage 120 and the anode off gas sent from the circulation flow passage 160 toward the fuel cell stack 50. The confluence channel 170 is a cylindrical channel that extends along the Y-axis direction. In the present embodiment, the two broken lines drawn along the Y-axis direction at the connection position Cn1 indicate the region occupied by the confluence channel 170 at the connection position Cn1.

  FIG. 2 is an explanatory diagram showing a positional relationship among the supply flow channel 120, the circulation flow channel 160, and the merge flow channel 170. FIG. 2 is a cross-sectional view of the connection position Cn1 in FIG. 1 viewed from the arrow II-II. The opening located at the position where the supply channel 120 is connected to the merging channel 170 is referred to as a first opening 122. The opening located at the position where the circulation flow path 160 is connected to the merging flow path 170 is referred to as a second opening 162.

  A cross section of the merging flow path 170 at the connection position Cn1 viewed from the arrow II-II is referred to as a cross section 170P. The first opening 122 is arranged in one region (+ side in the X axis direction) divided by a straight line L extending along the Z axis direction through the center C of the cross section 170P. The second opening 162 is arranged in the other region (the − side in the X-axis direction) divided by the straight line L.

  Further, the first opening 122 and the second opening 162 are arranged at positions overlapping the cross section 170P. In other words, the cross section 170P is arranged within the range where the first opening 122 and the second opening 162 exist in the Y-axis direction.

  The anode gas is sent from the supply channel 120 connected to the merging channel 170 from the + side in the Z-axis direction. On the other hand, the anode off gas is sent from the circulation flow path 160 connected to the merging flow path 170 from the − side in the Z-axis direction. Anode gas sent from one region (+ side in the X-axis direction) divided by the straight line L to the confluence channel 170 and anode off gas sent from the other region (-side in the X-axis direction) divided by the straight line L As a result, the swirling flow S is generated in the confluent flow path 170.

  According to the embodiment described above, the swirling flow S is easily generated in the confluent flow path 170, so that the anode gas and the anode off gas are sufficiently mixed. As a result, since the mixed gas has a uniform concentration, it is possible to prevent the gas from being sent to the fuel cell stack 50 while the concentration of the gas is not uniform. Therefore, it is possible to prevent the cell voltage from being lowered and the catalyst from being deteriorated due to the presence of the single cell 55 in which the hydrogen concentration is insufficient among the single cells 55 in the fuel cell stack 50.

B. Second embodiment:
FIG. 3 is an explanatory diagram showing the configuration of the fuel cell system 20a in the second embodiment. The fuel cell system 20a includes the supply channel 120a different from the supply channel 120 according to the first embodiment and the circulation channel 160a different from the circulation channel 160 according to the first embodiment. The configuration is similar to that of the fuel cell system 20 in FIG. The position where the supply flow path 120a and the circulation flow path 160a are connected to the merging flow path 170 is referred to as a connection position Cn2. The two broken lines drawn along the Y-axis direction at the connection position Cn2 indicate the area occupied by the confluence channel 170 at the connection position Cn2.

  The supply channel 120a is connected to the merging channel 170 from the + side in the Z-axis direction. The circulation channel 160a is connected to the merging channel 170 from the − side in the Z-axis direction. The supply flow channel 120a and the circulation flow channel 160a are connected to the merging flow channel 170 at positions displaced in the Y-axis direction. The position shifted in the Y-axis direction means a position where the first opening 122a (shown in FIG. 4) and the second opening 162a (shown in FIG. 5) do not overlap each other in the Y-axis direction. ..

  FIG. 4 is an explanatory diagram showing a positional relationship between the supply flow channel 120a and the merge flow channel 170. FIG. 4 is a cross-sectional view of the connection position Cn2 in FIG. 3 viewed from the arrow IV-IV. The opening located at the position where the supply flow path 120a is connected to the merging flow path 170 is referred to as a first opening 122a.

  A cross section of the merging flow path 170 at the connection position Cn2 viewed from the arrow IV-IV is referred to as a cross section 170P1. The first opening 122a is arranged in one region (+ side in the X-axis direction) divided by a straight line L1 extending along the Z-axis direction through the center C1 of the cross section 170P1.

  The anode gas is sent from the supply channel 120a connected to the merge channel 170 from the + side in the Z-axis direction. A swirl flow S1 is generated in the confluence channel 170 by the anode gas sent to the confluence channel 170 from one region (+ side in the X-axis direction) divided by the straight line L1.

  FIG. 5 is an explanatory diagram showing a positional relationship between the circulation flow channel 160a and the merge flow channel 170. FIG. 5 is a cross-sectional view of the connection position Cn2 in FIG. 3 viewed from the arrow VV. The opening at the position where the circulation flow path 160a is connected to the merging flow path 170 is referred to as a second opening 162a.

  A cross section of the merging flow path 170 at the connection position Cn2 viewed from the arrow V-V is a cross section 170P2. The second opening 162a is arranged in one region (+ side in the X-axis direction) divided by a straight line L2 extending along the Z-axis direction through the center C2 of the cross section 170P2.

  The anode off gas is sent from the circulation flow path 160a connected to the merging flow path 170 from the − side in the Z-axis direction. A swirl flow S2 is generated in the confluent flow passage 170 by the anode off gas sent from the other region (+ side in the X-axis direction) divided by the straight line L2. The swirl flow S2 is a swirl flow that is in reverse rotation to the swirl flow S1.

  According to the embodiment described above, the anode gas sent from the supply passage 120a and the anode off gas sent from the circulation passage 160a generate the swirling flow S1 and the swirling flow S2 in the confluent flow passage 170. The swirling flow S1 and the swirling flow S2 are swirling flows of reverse rotation. Since the swirling flow S1 and the swirling flow S2 are generated at positions displaced in the Y-axis direction, a turbulent flow that facilitates mixing of the anode gas and the anode off gas is likely to occur. As a result, since the mixed gas has a uniform concentration, it is possible to prevent the gas from being sent to the fuel cell stack 50 while the concentration of the gas is not uniform. Therefore, it is possible to prevent the cell voltage from being lowered and the catalyst from being deteriorated due to the presence of the single cell 55 in which the hydrogen concentration is insufficient among the single cells 55 in the fuel cell stack 50.

C. Third embodiment:
FIG. 6 is an explanatory diagram showing the configuration of the fuel cell system 20b in the third embodiment. The fuel cell system 20b according to the first embodiment is different from the supply passage 120 according to the first embodiment in that it includes a supply passage 120b different from the supply passage 120 according to the first embodiment and a circulation passage 160b different from the circulation passage 160 according to the first embodiment. It has the same configuration as the fuel cell system 20. The position where the supply flow path 120b and the circulation flow path 160b are connected to the merging flow path 170 will be referred to as a connection position Cn3. Note that the four broken lines drawn along the Y-axis direction at the connection position Cn3 indicate the region occupied by the confluence channel 170 at the connection position Cn3.

  The supply channel 120b has two branch channels 128. The branch channel 128 is connected to the merging channel 170 from the + side in the Z-axis direction. The circulation flow path 160b has two branch flow paths 168. The branch channel 168 is connected to the merging channel 170 from the − side in the Z-axis direction. The two branch channels 128 and the two branch channels 168 are connected to the merging channel 170 at positions displaced in the Y-axis direction.

  Each of the two branch flow channels 128 is on the + side in the X-axis direction when viewed from the center of the cross section of the cross section of the confluent flow channel 170, like the supply flow channel 120a in the second embodiment (illustrated in FIG. 4). The part is connected from the + side in the Z-axis direction. Like the circulation channel 160a in the second embodiment (illustrated in FIG. 5 ), the two branch channels 168 are on the + side in the X-axis direction when viewed from the center of the cross section of the merge channel 170. The part is connected from the − side in the Z-axis direction.

  According to the embodiment described above, the swirling flow S1 is generated in the confluent flow passage 170 by the anode gas sent from the two branch flow passages 128, and the swirl flow is generated by the anode off gas sent from the two branch flow passages 168. S2 is generated in the confluence channel 170. Since the two branch channels 128 and the two branch channels 168 are connected to the merging channel 170 at positions displaced in the Y-axis direction, the swirling flow S1 and the swirling flow S2 are respectively It occurs from a position displaced in the Y-axis direction. Therefore, the turbulent flow that promotes the mixing of the anode gas and the anode off gas is more likely to occur. As a result, since the mixed gas has a uniform concentration, it is possible to prevent the gas from being sent to the fuel cell stack 50 while the concentration of the gas is not uniform. Therefore, it is possible to prevent the cell voltage from being lowered and the catalyst from being deteriorated due to the presence of the single cell 55 in which the hydrogen concentration is insufficient among the single cells 55 in the fuel cell stack 50.

D. Modification:
In the first embodiment, the second embodiment, and the third embodiment, the merging passage 170 is a passage extending along the Y-axis direction, but the present invention is not limited to this. For example, the confluent channel 170 has a channel portion extending along the Y-axis direction from a position where the supply channel 120 and the circulation channel 160 are connected to the confluent channel 170, and a portion extending along the X-axis direction. The flow channel may include at least one of the portions extending along the Z-axis direction and the connection portion that connects the flow channel portion and the fuel cell stack 50.

  In the third embodiment, the number of the branch channels 128 and the number of the branch channels 168 are two, but the present invention is not limited to this. For example, the number of branch channels 128 and the number of branch channels 168 may each be three or more.

  The present invention is not limited to the above-described embodiments, examples, and modified examples, and can be realized with various configurations without departing from the spirit of the invention. For example, technical features in the embodiments, examples, and modified examples corresponding to the technical features in each mode described in the section of the outline of the invention are to solve some or all of the above problems, or In order to achieve a part or all of the above effects, it is possible to appropriately replace or combine them. If the technical features are not described as essential in this specification, they can be deleted as appropriate.

20, 20a, 20b... Fuel cell system 50... Fuel cell stack 55... Single cell 100... Anode gas supply system 110... Hydrogen tanks 120, 120a, 120b... Supply channel 122, 122a... First opening 125... Open/close valve 128... Branch flow path 130... Exhaust flow path 140... Gas-liquid separation part 150... Drainage flow path 155... Drain valve 160, 160a, 160b... Circulation flow path 162, 162a... Second opening 165... Circulation pump 168... Branch Channel 170P, 170P1, 170P2... Cross section 170... Confluent channel C, C1, C2... Center Cn, Cn1, Cn2, Cn3... Connection position L, L1, L2... Straight line S, S1, S2... Swirling flow

Claims (2)

A fuel cell system comprising: a fuel cell; and a tank for storing an anode gas supplied to the fuel cell,
A supply flow path that is connected to the tank and sends an anode gas toward the fuel cell;
An exhaust flow path for sending anode off-gas exhausted from the fuel cell,
A circulation flow path that is connected to the discharge flow path and circulates the anode off-gas to the fuel cell;
A confluent flow path that is connected to the supply flow path and the circulation flow path and sends the anode gas and the anode off-gas toward the fuel cell,
The supply channel is connected to the confluent channel from a first direction,
The circulation flow path is connected to the confluence flow path from a second direction which is a direction opposite to the first direction,
The confluent channel is formed from a first opening at a position where the supply channel is connected to the confluent channel and a second opening at a position where the circulation channel is connected to the confluent channel. A channel portion extending in a third direction orthogonal to the first direction and the second direction,
The positional relationship between the first opening and the second opening is
The flow path portion is divided by a straight line that extends along the first direction and the second direction through the center of the cross section in the cross section when cut in a plane perpendicular to the third direction. The first opening and the second opening are arranged on the side of the one region, and the first opening and the second opening are displaced from each other in the third direction. A fuel cell system, which is a positional relationship arranged in the. The fuel cell system according to claim 1, wherein
  The supply channel includes two branch channels,
  The circulation channel includes two branch channels,
  The two branch flow channels of the supply flow channel and the two branch flow channels of the circulation flow channel are connected to the confluent flow channel at positions displaced from each other in the third direction. , Fuel cell system.

Images