JP6876904B2 - Stack aging method - Google Patents

Description

The present invention, stack and relates aging process of stack used in a solid polymer fuel cell system that includes a power conversion circuit board connected to the stack.

A fuel cell is one in which a fuel gas such as hydrogen and an oxidant gas such as air are electrochemically reacted to generate electricity and heat at the same time.

The polymer electrolyte fuel cell is composed of a cell in which an electrolyte membrane-electrode assembly (hereinafter referred to as “MEA”) is sandwiched between a pair of separators.

The MEA is provided with a pair of electrodes on both main surfaces of a polymer electrolyte membrane (hereinafter, also referred to as “electrolyte membrane”) that selectively transports hydrogen ions.

The separators are arranged on both sides of the MEA to mechanically fix the MEA, and also have conductivity because the adjacent MEAs are electrically connected to each other in series.

A groove is formed on the surface of the separator in contact with the MEA, which serves as a gas flow path for supplying a reaction gas such as hydrogen or air to the electrode and carrying away the gas generated by the reaction or excess gas. A groove is formed on the surface of the separator opposite to the surface in contact with the MEA, which serves as a cooling water flow path for supplying and discharging the cooling water for recovering the heat generated by the reaction.

Many fuel cells have a laminated structure in which many MEAs and separators are stacked, and a pair of current collector plates for extracting electricity generated by the reaction are arranged at both ends in the laminated direction. .. Such a laminate is called a stack.

The stack has a reaction gas manifold that penetrates the cell and supplies and discharges the reaction gas to the gas flow path of the separator, and a cooling water manifold that penetrates the cell and supplies and discharges the cooling water to the cooling water flow path of the separator. ..

The current generated in the stack is adjusted by a power conversion circuit board electrically connected to the current collector and then taken out of the fuel cell system. The current collector plate and the power conversion circuit board are connected by a harness, and the current collector plate is provided with terminals for attaching the harness.

The positional relationship between the stack and the power conversion circuit board in the fuel cell system can take various forms depending on the layout. As shown in FIG. 7, the power conversion circuit board 32 is arranged above the stack 31. When both are connected by a harness 33 (see, for example, Patent Document 1), or as shown in FIGS. 8 and 9, the power conversion circuit board 32 is arranged in the front-rear and left-right directions (horizontal direction, substantially horizontal direction) of the stack 31. Then, there is a case where both are connected by a harness 33 (see, for example, Patent Document 2).

In both cases, the partition 34 divides the inside of the fuel cell system housing into a space in which the stack 31 and the fuel reformer are arranged and a space in which the high voltage circuit such as the power conversion circuit board 32 is arranged.

Regardless of the positional relationship between the stack 31 and the power conversion circuit board 32 in Patent Document 1 and Patent Document 2, by shortening the length of the harness 33 to be connected as much as possible, the power due to the IR loss of the harness 33 can be obtained. Loss can be minimized.

JP-A-2010-092750 Japanese Unexamined Patent Publication No. 2009-158463

When the power conversion circuit board 32 is arranged above the stack 31 or in the front-back and left-right directions (horizontal direction, substantially horizontal direction) of the stack 31 as in the above conventional example, the terminal of the current collector plate is provided on the upper part of the stack 31. Is common.

When arranging the power conversion circuit board 32 below the stack 31, if the terminal of the current collector plate is provided on the upper part of the stack 31, the harness 33 becomes long, so that the terminal of the current collector plate is provided on the lower part of the stack 31. Can be considered.

By the way, in the stack manufacturing process, if the electrolyte membrane and ionomer, which are the materials constituting the MEA, lose water or impurities adhere to the catalyst surface during the catalyst layer manufacturing process, the MEA and the stack immediately after assembly are originally produced. The performance that should be generated cannot be exhibited.

Therefore, in the manufacturing process of the fuel cell system, the stack is used for the purpose of wetting the electrolyte membrane and ionomer and cleaning the surface of the catalyst after the stack is assembled and before being mounted on the fuel cell system. It is connected to an aging device to generate preliminary power generation as a stack activation process, and to inspect the performance of the stack.

During aging, the terminals of the stack and the aging device are electrically connected by a harness. If the terminals of the current collector plate are provided at the bottom of the stack, the terminals and harness may be damaged due to poor workability of attaching the harness. In addition, the connection with the harness may be insufficient and the contact resistance may increase. In either case, it is considered unsafe when a current flows through the terminals.

Since wiring for various measurements is also arranged in and around the harness of the aging device, when attaching to the terminal of the current collector plate at the bottom of the stack, it is better than when mounting on the fuel cell system. It has a large effect on the deterioration of workability.

It is conceivable to provide a terminal of the current collector plate at the bottom of the stack so that the stack is turned upside down during aging to connect the stacked upside down and the aging device.

However, if it is structurally difficult to hold the upside-down stack in that state, or if the reaction gas and cooling water are designed to flow inside the stack in the direction of gravity, the reaction will occur. During aging, the reaction gas and cooling water will flow inside the stack against gravity in order to allow the gas and cooling water to flow into the stack from the original inlet side, or the reaction gas and cooling water will flow inside the stack. During aging, the reaction gas and cooling water flow into the stack from the original outlet side so that the product flows in the direction of gravity. Therefore, there is a problem that the result of the performance inspection may differ from the original performance.

In view of the above problems, the present invention is a method for aging a stack used in a fuel cell system having good workability during aging while minimizing power loss even if a power conversion circuit board is arranged below the stack. The purpose is to provide.

In order to solve the above problems, in the stack aging method of the present invention, a pair of cells in which an electrolyte film-electrode junction is sandwiched between a pair of separators is laminated at both ends in a substantially horizontal direction. A fuel cell system comprising a stack with a power plate and a power conversion circuit board located below the stack and electrically connected to the current collector, wherein the stack penetrates the cell. It has a reaction gas manifold that supplies and discharges reaction gas to the cell, and a cooling water manifold that supplies and discharges cooling water that penetrates the cell and recovers heat generated during power generation in the cell. Each of the current collector plates includes an upper terminal that draws current from above the cooling water inlet and the cooling water outlet of the cooling water manifold, and a lower terminal that draws current from the lower part of the stack. , A method of aging a stack used in a fuel cell system, which is electrically connected only to the lower terminal by a harness. The upper terminal of the stack and an aging device are electrically connected by a harness. It is characterized by performing aging.

In the fuel cell system to which the present invention is applied, even if the power conversion circuit board is arranged below the stack, the length of the harness connecting the stack and the power conversion circuit board can be shortened by this configuration. Power loss due to IR loss can be minimized.

Further, the aging process of the stack of the present invention is a aging process of the stack used for the fuel cell system, and the upper terminal of the stack, and aging device, the aging electrically connected by a harness This method improves the workability of aging.

In the stack aging method of the present invention, the stack collecting plate includes an upper terminal that draws current from above the cooling water inlet and cooling water outlet of the cooling water manifold, and a lower terminal that draws current from the lower part of the stack. , The power conversion circuit board located below the stack is a stack aging method used in a fuel cell system in which only the lower terminal is electrically connected by a harness, and the upper terminal of the stack and the aging device are harnessed. Since aging is performed by electrically connecting with, the workability of aging is improved.

Schematic vertical cross-sectional view showing a cross section when the stack used in the fuel cell system according to the first embodiment of the present invention is cut in a plane including the central axis of a pair of cooling water manifolds. Schematic side view of the stack used in the fuel cell system according to the first embodiment of the present invention when viewed from the entrance / exit side of each manifold. Schematic vertical sectional view showing the configuration of the fuel cell system according to the first embodiment of the present invention. External perspective view of the stack used in the fuel cell system according to the first embodiment of the present invention. Schematic side view showing a connection state between the stack and the aging device when the stack used in the fuel cell system according to the first embodiment of the present invention is being aged. Schematic side view of a main part showing a connection state between a stack and a power conversion circuit board in the fuel cell system according to the first embodiment of the present invention. Schematic perspective view of a main part showing a connection state between a stack and a power conversion circuit board in a conventional fuel cell system disclosed in Patent Document 1. Schematic top view of a main part showing a connection state between a stack and a power conversion circuit board in a conventional fuel cell system disclosed in Patent Document 2. Schematic side view of a main part showing a connection state between a stack and a power conversion circuit board in a conventional fuel cell system disclosed in Patent Document 2.

A fuel cell system to which the present invention is applied is a stack in which a large number of cells sandwiching an electrolyte membrane-electrode junction between a pair of separators are laminated in a substantially horizontal direction, and a pair of current collector plates are provided at both ends in the stacking direction. A fuel cell system including a power conversion circuit board arranged below the stack and electrically connected to the current collector plate, the stack penetrating the cell and reacting to the cell. Each of the current collector plates has a reaction gas manifold that supplies and discharges gas, and a cooling water manifold that supplies and discharges cooling water that penetrates the cell and recovers heat generated during power generation in the cell. The power conversion circuit board includes only the lower terminal, which includes an upper terminal for taking out current from above the cooling water inlet and the cooling water outlet of the cooling water manifold and a lower terminal for taking out current from the lower part of the stack. It is characterized by being electrically connected by a harness.

With this configuration, even if the power conversion circuit board is placed below the stack, the length of the harness that connects the stack and the power conversion circuit board is longer than when the upper terminal of the stack and the power conversion circuit board are connected by a harness. Since it can be shortened, the power loss due to the IR loss of the harness can be reduced.

In addition, by arranging the power conversion circuit board below the stack, even if flammable fuel gas such as hydrogen leaks from the stack, these fuel gases will flow to the top of the stack lighter than air. , The possibility of flowing into the power conversion circuit board having a high voltage is reduced, and the possibility of causing a problem such as ignition can be reduced.

Further, since the upper terminal can be used for connection with the aging device during aging, workability during aging can be ensured.

In the fuel cell system applying the present invention, the upper terminal, than the upper end surface of the collector plate protrudes upward, the lower terminal, be projected lower than the lower end surface of the collector plate Good.

With this configuration, the upper terminals can be projected upward from the upper end surface (of the laminated body) of the stack, so that workability during aging can be further improved. Further, since the lower terminal can be projected below the lower end surface (of the laminated body) of the stack, the length of the harness connecting the stack and the power conversion circuit board can be further shortened, and the IR loss of the harness can be further shortened. The power loss due to the above can be further reduced.

Further, in the fuel cell system to which the present invention is applied, the power conversion circuit board may be provided with a connection terminal electrically connected to the lower terminal by the harness at the upper part of the power conversion circuit board.

With this configuration, the length of the harness connecting the stack and the power conversion circuit board can be further shortened, and the power loss due to the IR loss of the harness can be further reduced.

Further, in the fuel cell system to which the present invention is applied, the cooling water inlet may be located above the cooling water outlet, and the cooling water may flow from top to bottom with respect to the cell.

This configuration allows the temperature at the top of the stack to be lower. When using the upper terminal during aging, the upper terminal of the current collector plate will be located at the upper part where the temperature of the stack is lower.

If power is generated at a higher current or temperature than when the fuel cell system is installed to check the performance of the stack during aging, the upper terminal of the current collector plate will become hotter, which may be unsafe. Conceivable. By using the upper terminal during aging in a configuration in which the temperature of the upper part of the stack is lower, the temperature of the upper terminal can be kept lower. As a result, safety during aging can be improved.

Further, in the fuel cell system to which the present invention is applied, the reaction gas inlet of the reaction gas manifold is located above the reaction gas outlet of the reaction gas manifold, and the reaction gas is from top to bottom with respect to the cell. May flow towards .

With this configuration, the reaction gas inlet and the cooling water inlet are located close to each other at the upper part of the stack. Since the power generation reaction is concentrated near the reaction gas inlet due to the high concentration of the reaction gas, the stack temperature near this is higher, but the cooling water inlet is near the reaction gas inlet for efficient cooling. It is possible to suppress the temperature rise near the reaction gas inlet.

As a result, the temperature distribution at the top and bottom of the stack can be made more uniform, so that local deterioration due to high temperature can be suppressed, and as a result, the durability of the stack can be improved.

Further, even when condensed water is generated in the reaction gas flow path in the stack, the condensed water can be discharged from the reaction gas outlet of the stack by utilizing the flow and gravity of the reaction gas, and the condensed water is generated in the reaction gas flow path. It is possible to prevent the condensed water from obstructing the flow of the reaction gas.

The stack aging method of the present invention is a stack aging method used in the fuel cell system having the above configuration, in which the upper terminal of the stack and the aging device are electrically connected by a harness to perform aging. It is characterized by that.

By this method, workability when connecting the stack and the aging device with a harness can be improved as compared with the case where the stack and the aging device are connected to the lower terminal. It is possible to prevent unsafety due to insufficient connection between the terminals of the stack and the harness. As a result, work efficiency and safety during aging can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments.

(Embodiment 1)
FIG. 1 is a schematic vertical sectional view showing a cross section when a stack used in the fuel cell system according to the first embodiment of the present invention is cut in a plane including a central axis of a pair of cooling water manifolds. FIG. 2 is a schematic side view of the stack used in the fuel cell system according to the first embodiment of the present invention when viewed from the entrance / exit side of each manifold. FIG. 3 is a schematic vertical sectional view showing the configuration of the fuel cell system according to the first embodiment of the present invention.

FIG. 4 is an external perspective view of a stack used in the fuel cell system according to the first embodiment of the present invention. FIG. 5 is a schematic side view showing a connection state between the stack and the aging device when the stack used in the fuel cell system according to the first embodiment of the present invention is being aged. FIG. 6 is a schematic side view of a main part showing a connection state between the stack and the power conversion circuit board in the fuel cell system according to the first embodiment of the present invention.

As shown in FIGS. 1 to 6, the stack 1 used in the fuel cell system 15 of the present embodiment is formed at both ends in the stacking direction of a laminated body 4 in which a large number of cells 4a in which MEA2 is sandwiched between a pair of separators 3 are laminated. A pair of current collector plates 5 are provided. In order to apply fastening pressure to the stack 1 and hold it as a unit, a pair of end plates 6 are placed on the surface of the pair of current collector plates 5 opposite to the surface facing the laminated body 4 (further outside the current collector plates 5). Both ends plates 6 are fastened with the annular band 22 so that a force for compressing the laminated body 4, the pair of current collector plates 5 and the pair of end plates 6 is applied in the stacking direction.

The stack 1 is a reaction gas manifold 7 that penetrates the cell 4a to supply and discharge the reaction gas to the cell 4a, and cooling water that penetrates the cell 4a and supplies and discharges cooling water that recovers the heat generated during power generation in the cell 4a. It has a manifold 8.

In FIG. 1, which shows a cross section when the stack 1 is cut in a plane including the central axes of the pair of cooling water manifolds 8, the reaction gas manifold 7 is not shown, but the stack 1 is formed by the central axes of the pair of reaction gas manifolds 7. In the cross section when cut in a plane including, the cooling water manifold 8, the cooling water inlet 9, and the cooling water outlet 10 in FIG. 1 are replaced with the reaction gas manifold 7, the reaction gas inlet 13, and the reaction gas outlet 14, respectively. Corresponds to.

The current collector plate 5 includes an upper terminal 11 that draws current from above the cooling water inlet 9 and the cooling water outlet 10 of the cooling water manifold 8, and a lower terminal 12 that draws current from the lower part of the stack 1. The upper terminal 11 projects upward from the upper surface of the stack 1, and the lower terminal 12 projects downward from the lower surface of the stacked portion of the stack 1. The pair of end plates 6 are integrally provided with leg portions 6a projecting downward from the lower terminal 12.

One end plate 6 of the pair of end plates 6 is provided with a reaction gas inlet 13 and a reaction gas outlet 14 of the reaction gas manifold 7, a cooling water inlet 9 and a cooling water outlet 10 of the cooling water manifold 8, respectively. There is. Since the reaction gas requires a fuel gas such as hydrogen and an oxidant gas such as air, two reaction gas inlets 13 and two reaction gas outlets 14 are provided.

In the housing of the fuel cell system 15, the power conversion circuit board 16 is arranged below the stack 1, and is electrically connected only to the lower terminal 12 by the harness 17. The electric power generated by the stack 1 is adjusted by the power conversion circuit board 16 and then taken out to the outside of the fuel cell system 15. The power conversion circuit board 16 is composed of circuits such as a booster circuit and an inverter circuit, and sensors such as a voltage sensor and a current sensor.

Air is supplied to the stack 1 from the air blower 18 to one reaction gas inlet 13, and the surplus gas after being used for power generation is discharged from one reaction gas outlet 14. Further, a fuel gas containing hydrogen is supplied from the fuel reformer 19 to the other reaction gas inlet 13, and the surplus gas after being used for power generation is provided in the fuel reformer 19 from the other reaction gas outlet 14. It is supplied to the burner and used for burning the burner to maintain the temperature of the fuel reformer 19. A raw material gas such as city gas, which is a raw material for the fuel gas, is supplied to the fuel reformer 19 from the outside of the fuel cell system 15 and reformed into a fuel gas containing hydrogen.

Cooling water is supplied to the stack 1 from the heat exchanger 20 to the cooling water inlet 9, and the heat generated in the stack 1 by power generation is recovered by the cooling water flowing through the stack 1, and then heat is exchanged again from the cooling water outlet 10. It is returned to the vessel 20.

Hot water having a low temperature is supplied to the heat exchanger 20 from the hot water storage tank 21, and after heat exchange with the cooling water to raise the temperature, the heat exchanger 20 is returned to the hot water storage tank 21 again. Hot water is supplied from the hot water storage tank 21 to the outside of the fuel cell system 15, and instead, water is replenished from the outside.

The present embodiment is characterized in that the power conversion circuit board 16 is arranged below the stack 1 and is electrically connected only to the lower terminal 12 by a harness 17. As a result, the length of the harness 17 can be shortened. The lower side means that the upper end surface of the power conversion circuit board 16 is at the same height or lower position as the lower end surface of the stack 1. If the power conversion circuit board 16 is significantly below the stack 1, the length of the harness 17 becomes long, so it is preferable to arrange the power conversion circuit board 16 in the vicinity of the stack 1.

In the present embodiment, the terminals of the current collector plate 5 arranged on the upper part of the stack 1 are called the upper terminal 11, but the upper terminal 11 is more than the upper end surface of the stack 1, that is, the upper end surface of the current collector plate 5. It is preferable that it protrudes upward. As a result, workability during aging can be further improved.

Other configurations of the upper terminal 11 include a configuration in which the current collector plate 5 protrudes horizontally at the same height as the upper end surface, and a configuration in which the current collector plate 5 projects horizontally at a height lower than the upper end surface of the current collector plate 5. Etc. can also be taken.

In the present embodiment, the terminals of the current collector plate 5 arranged at the lower part of the stack 1 are called lower terminals 12, but the lower terminal 12 is closer to the lower end surface of the stack 1, that is, the lower end surface of the current collector plate 5. It is preferable that it protrudes downward. As a result, the length of the harness 17 connecting the stack 1 and the power conversion circuit board 16 can be shortened.

Other configurations of the lower terminal 12 include a configuration in which the lower end surface of the current collector plate 5 projects in the horizontal direction at the same height as the lower end surface, and a configuration in which the lower terminal surface 5 protrudes in the horizontal direction at a position higher than the lower end surface of the current collector plate 5. Can also be taken.

The shape of the current collector plate 5 is generally a rectangular plate having the same area as the separators 3 and MEA2 to be laminated, and the terminals are projected. For the connection between the terminals of the current collector plate 5 (upper terminal 11 and lower terminal 12) and the harness 17, it is common to use bolts and nuts to ensure a secure connection.

Therefore, there is a hole for inserting a bolt for inserting the bolt. Alternatively, it may have a U-shaped terminal shape. In order to improve the mounting workability of the harness 17, it is preferable to attach a caulking nut to the terminals (upper terminal 11 and lower terminal 12) of the current collector plate 5 or the terminal portion of the harness 17 in advance.

As the material of the current collector plate 5, a metal having high conductivity such as aluminum or brass is used. Further, it is preferable that the portion in contact with the separator 3 and the portion in contact with the harness 17 are plated with a metal such as gold or carbon coated, which has low contact resistance and high corrosion resistance.

The arrangement of the cooling water inlet 9 and the cooling water outlet 10 in the stack 1 can take various positions, but the cooling water inlet 9 is located above the cooling water outlet 10 and the cooling water is directed to the cell 4a. It is preferable that the water flows from above to below.

As a result, the temperature of the upper terminal 11 can be suppressed to a lower level. Further, when the upper terminal 11 is used during aging, even if the temperature of the upper terminal 11 rises, the temperature of the upper terminal 11 can be suppressed to a lower level, so that safety can be improved.

The reaction gas inlet 13 and the reaction gas outlet 14 in the stack 1 can be arranged in various positions, but the cooling water inlet 9 is located above the cooling water outlet 10 and the cooling water is directed to the cell 4a. In the case of a configuration in which the reaction gas flows from the upper side to the lower side, it is preferable that the reaction gas inlet 13 is located above the reaction gas outlet 14 and the reaction gas flows from the upper side to the lower side with respect to the cell 4a.

As a result, the temperature near the reaction gas inlet 13 in which the power generation reaction is concentrated can be suppressed to a lower temperature. Since the temperature distributions at the upper and lower parts of the stack 1 can be made more uniform, the durability of the stack 1 can be improved.

In the present embodiment, the annular band 22 is arranged so as to surround the side surface of the stack 1, and the stack 1 is integrally fixed by the force with which the annular band 22 fastens the end plate 6. Another method of fastening the end plate 6 of the stack 1 is to use a plurality of bolts and nuts, but the structure can be simplified by using the annular band 22, and the stack 1 can be assembled. It is more preferable because it also improves workability.

The upper end of the annular band 22 is arranged so as to be at the same height as the upper end surface of the stack 1 or at a position lower than the upper end surface, and is configured so as not to be an obstacle when attaching the harness of the aging device to the upper terminal 11. There is.

Similarly, the lower end of the annular band 22 is arranged so as to be at the same height as the lower end surface of the stack 1 (excluding the leg portion 6a) or at a position higher than the lower end surface, and the power conversion circuit board 16 is connected to the lower terminal 12. It is configured so as not to be an obstacle when attaching the harness 17 for connecting to.

At the lower part (four corners of the lower surface) of the stack 1, leg portions 6a integrally formed with the end plate 6 project downward. The height of the leg portion 6a is higher than the length at which the lower terminal 12 projects downward from the lower end surface of the stack 1 (excluding the leg portion 6a), and the stack 1 is installed on a flat table. Even in this case, the lower terminal 12 does not come into contact with the base.

The leg portion 6a also has a role of protecting the lower terminal 12 so that a human hand or a conductive object does not come into contact with the lower terminal 12 unintentionally and become dangerous. On the other hand, a gap is provided between the adjacent legs 6a so that the harness 17 and tools can be inserted so as not to interfere with the attachment of the harness 17 for connecting to the power conversion circuit board 16 to the lower terminal 12. ..

In the stack 1 of the present invention, it is preferable that the upper terminal 11 and the aging device are electrically connected by a harness to perform aging. As the harness, a harness dedicated to the aging device may be used, or a harness 17 mounted on the fuel cell system 15 may be used.

The upper terminal 11 and the lower terminal 12 are made as short as possible within the range to which the harness can be connected. Thereby, the power loss due to the IR loss at the terminal can be reduced.

Therefore, when the stack 1 is installed on the flat work table of the aging device 23, only a narrow space corresponding to the length of the lower terminal 12 can be secured below the stack 1, and the harness 17 is attached. Or, there is not enough work space when turning the fixing bolts. However, as shown in FIG. 5, by using the upper terminal 11 during aging, work efficiency and safety during aging can be improved.

As described above, in the fuel cell system 15 of the present embodiment, the pair of current collector plates 5 at both ends in the stacking direction of the laminated body 4 in which a large number of cells 4a sandwiching the MEA 2 between the pair of separators 3 are stacked in a substantially horizontal direction. A stack 1 provided with the above, and a power conversion circuit board 16 arranged below the stack 1 and electrically connected to the current collector plate 5 are provided.

Then, the stack 1 supplies and discharges a reaction gas manifold 7 that penetrates the cell 4a to supply and discharge the reaction gas to the cell 4a, and a cooling water that penetrates the cell 4a and recovers the heat generated during power generation in the cell 4a. It has a cooling water manifold 8.

Further, each of the current collector plates 5 includes an upper terminal 11 that draws current from above the cooling water inlet 9 and the cooling water outlet 10 of the cooling water manifold 8, and a lower terminal 12 that draws current from the lower part of the stack 1. .. Further, the power conversion circuit board 16 is electrically connected only to the lower terminal 12 by a harness 17.

With this configuration, even if the power conversion circuit board 16 is arranged below the stack 1, the stack 1 and the power conversion circuit board are more than when the upper terminal 11 of the stack 1 and the power conversion circuit board 16 are connected by the harness 17. Since the length of the harness 17 connecting the 16 can be shortened, the power loss due to the IR loss of the harness 17 can be reduced.

Further, by arranging the power conversion circuit board 16 below the stack 1, even if a flammable fuel gas such as hydrogen leaks from the stack 1, these fuel gases are lighter than air and move above the stack 1. Since the gas flows, the possibility of flowing into the power conversion circuit board 16 having a high voltage is reduced, and the possibility of causing a problem such as ignition can be reduced.

Further, since the upper terminal 11 can be used for connection with the aging device 23 during aging, workability during aging can be ensured.

Further, in the stack 1 of the present embodiment, the upper terminal 11 projects upward from the upper end surface of the current collector plate 5, and the lower terminal 12 projects downward from the lower end surface of the current collector plate 5.

With this configuration, the upper terminal 11 can be projected upward from the upper end surface (of the laminated body 4) of the stack 1, so that the upper terminal 11 is projected from the upper part of the side surface of the stack 1 during aging. Workability can be further improved. Further, since the lower terminal 12 can be projected below the lower end surface (of the laminated body 4) of the stack 1, power conversion with the stack 1 is performed as compared with the case where the lower terminal 12 is projected from the lower portion of the side surface of the stack 1. The length of the harness 17 connecting the circuit board 16 can be further shortened, and the power loss due to the IR loss of the harness can be further reduced.

Further, when the annular band 22 is arranged so as to surround the side surface of the stack 1 and the annular band 22 integrally fixes the stack 1 by the force for fastening the end plate 6, the upper terminal 11 and the lower terminal 12 are connected. It does not get in the way of the annular band 22.

When the upper terminal 11 or the lower terminal 12 protrudes from the side surface of the stack 1, the annular band is particularly arranged so that the upper terminal 11 or the lower terminal 12 does not interfere with the fastening and integration of the stack 1 by the annular band 22. When the 22 is made of metal (conductive), the annular band 22 needs to have a notch or a hole to avoid the upper terminal 11 or the lower terminal 12 so that the upper terminal 11 or the lower terminal 12 does not come into contact with the annular band 22. Therefore, the notch or the hole increases the manufacturing cost of the annular band 22 or reduces the strength of the annular band 22.

Further, the power conversion circuit board 16 in the present embodiment is provided with a connection terminal 16a that is electrically connected to the lower terminal 12 by the harness 17 at the upper part of the power conversion circuit board 16, so that the power conversion circuit board 16 is provided. The length of the harness 17 connecting the stack 1 and the power conversion circuit board 16 can be further shortened as compared with the case where the connection terminal 16a is provided at a position other than the upper part of the harness 17, and the power loss due to the IR loss of the harness 17 can be further reduced. It can be made smaller.

Further, since the cooling water inlet 9 of the stack 1 in the present embodiment is located above the cooling water outlet 10 and the cooling water flows from the top to the bottom with respect to the cell 4a, the upper part of the stack 1 The temperature can be lower than other parts. When the upper terminal 11 is used during the aging of the stack 1, the upper terminal 11 of the current collector plate 5 is located at the upper part where the temperature of the stack 1 is lower.

If power is generated at a higher current or temperature than when the fuel cell system 15 is mounted for performance inspection of the stack 1 during aging, the upper terminal 11 of the current collector plate 5 becomes hotter, which is unsafe. There is a possibility that it will become.

In this embodiment, the temperature of the upper part of the stack 1 is lowered, and the temperature of the upper terminal 11 can be kept lower by using the upper terminal 11 at the time of aging. As a result, safety during aging can be improved.

Further, the reaction gas inlet 13 of the reaction gas manifold 7 of the stack 1 in the present embodiment is located above the reaction gas outlet 14 of the reaction gas manifold 7, and the reaction gas flows from top to bottom with respect to the cell 4a. By flowing toward the stack 1, the reaction gas inlet 13 and the cooling water inlet 9 are located close to each other on the upper part of the stack 1. Since the power generation reaction is concentrated near the reaction gas inlet 13 due to the high concentration of the reaction gas, the temperature of the stack 1 in this vicinity becomes higher, but the cooling water inlet 9 is near (near) the reaction gas inlet 13. ), It is possible to cool efficiently, and it is possible to suppress a temperature rise in the vicinity (near) of the reaction gas inlet 13.

As a result, the temperature distribution of the upper part and the lower part of the stack 1 can be made more uniform, so that local deterioration due to high temperature can be suppressed, and as a result, the durability of the stack 1 can be improved.

Further, even when condensed water is generated in the reaction gas flow path in the stack 1, the condensed water can be discharged from the reaction gas outlet 14 of the stack 1 by utilizing the flow and gravity of the reaction gas, and the reaction gas flow path. It is possible to prevent the condensed water generated in the above from obstructing the flow of the reaction gas.

Further, in the aging of the stack 1 in the present embodiment, the upper terminal 11 of the stack 1 and the aging device 23 are electrically connected by the harness 17 to perform aging.

By this aging method of the stack 1, the workability when connecting the stack 1 and the aging device 23 with the harness 17 can be improved as compared with the case where the aging device 23 is connected to the lower terminal 12 with the harness 17. It is possible to prevent unsafeness due to insufficient connection between the terminal of the stack 1 and the harness 17. As a result, work efficiency and safety during aging can be improved.

The fuel cell system to which the present invention is applied can shorten the length of the harness connecting the stack and the power conversion circuit board, and the stack aging method of the present invention ensures workability during aging. Therefore, it can be suitably used as a fuel cell system of various types including those for home cogeneration.

1 stack 2 MEA
3 Separator 4 Laminated body 4a Cell 5 Current collector plate 6 End plate 6a Leg 7 Reaction gas manifold 8 Cooling water manifold 9 Cooling water inlet 10 Cooling water outlet 11 Upper terminal 12 Lower terminal 13 Reaction gas inlet 14 Reaction gas outlet 15 Fuel cell System 16 Power conversion circuit board 16a Connection terminal 17 Harness 23 Aging device

Claims (1)

A stack in which a large number of cells sandwiching an electrolyte membrane-electrode assembly between a pair of separators are laminated in a substantially horizontal direction and a pair of current collector plates are provided at both ends in the stacking direction.
A power conversion circuit board located below the stack and electrically connected to the current collector is provided.
The stack has a reaction gas manifold that penetrates the cell and supplies and discharges the reaction gas to the cell, and a cooling water manifold that penetrates the cell and supplies and discharges cooling water that recovers heat generated during power generation in the cell. And have
Each of the current collector plates includes an upper terminal that draws current from above the cooling water inlet and cooling water outlet of the cooling water manifold, and a lower terminal that draws current from the lower part of the stack.
The power conversion circuit board is a stack aging method used in a fuel cell system, which is electrically connected only to the lower terminal by a harness.
A stack aging method in which the upper terminal of the stack and an aging device are electrically connected by a harness to perform aging.

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