JP7470005B2 - Fuel cell and its insulating structure - Google Patents

Description

Embodiments of the present invention relate to fuel cells and their insulating structures.

In conventional fuel cells, to prevent leakage current generated by the fuel cell stack (power generation section) from being conducted to the outside via condensed water or cooling water, which could cause ground faults or electric shock, insulating piping made of insulating material is installed between the fuel cell stack and the supply or discharge piping for hydrogen-containing gas, oxygen-containing gas, or cooling water. By installing the insulating piping, an insulating distance is ensured, and the fuel cell is insulated from the outside.

Japanese Patent Application Laid-Open No. 8-329970

However, in conventional fuel cells, the number of piping connections increases due to the installation of insulating piping, and therefore the number of locations where hydrogen-containing gas, oxygen-containing gas, or cooling water leaks through the connections increases. In addition, the cost also increases due to the increase in the number of parts and installation locations. Furthermore, when insulating piping is installed, the installation position of the shutoff valve that stops the supply of hydrogen-containing gas or oxygen-containing gas to the fuel cell is installed away from the fuel cell by the length of the insulating piping. In other words, when the supply of hydrogen-containing gas or oxygen-containing gas is stopped, hydrogen-containing gas or oxygen-containing gas for the length of the insulating piping remains in the fuel cell. In order to prevent the remaining oxygen-containing gas from progressing the deterioration of the fuel cell, the remaining oxygen-containing gas can be reacted with the hydrogen-containing gas to be consumed, but the electricity generated by the power generation of the fuel cell at this time is not used, so the hydrogen-containing gas is consumed unnecessarily. In addition, when the hydrogen-containing gas and oxygen-containing gas are consumed, a pressure drop occurs in the fuel cell by the amount consumed. To prevent deformation of the fuel cell due to a drop in pressure, cooling water or hydrogen-containing gas can be supplied to the fuel cell, but in this case, it is necessary to increase the capacity of the cooling water tank to supply the cooling water, or to increase the supply of hydrogen-containing gas. Thus, conventional fuel cells have various problems associated with the installation of insulating piping.

The problem that the present invention aims to solve is to provide a fuel cell and its insulation structure that can ensure insulation from the outside without installing insulating piping.

The fuel cell according to this embodiment includes a fuel cell stack and a manifold. The fuel cell stack is formed by stacking a plurality of single-cell batteries. The manifold is disposed on a side of the fuel cell stack in a direction perpendicular to the stacking direction of the single-cell batteries. The manifold supplies the hydrogen-containing gas, oxygen-containing gas, or cooling water supplied to the inside of the manifold through a supply port provided in the manifold to the fuel cell stack, or discharges the hydrogen-containing gas, oxygen-containing gas, or cooling water discharged from the fuel cell stack to the outside of the manifold through a discharge port provided in the manifold. The shortest flow path distance from the fuel cell stack to the supply port or discharge port is equal to or greater than the insulation distance.

1 is a schematic perspective view showing a fuel cell according to a first embodiment; FIG. 11 is a schematic perspective view showing a fuel cell according to a second embodiment. FIG. 11 is a schematic perspective view showing a fuel cell according to a third embodiment.

Below, an embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to this embodiment. Also, the schematic diagrams referred to in the following description are diagrams showing the positional relationship of each component, and the dimensional ratios of each component do not necessarily match the actual ones. Also, in the drawings referred to in each embodiment, the same parts or parts having similar functions are given the same or similar symbols, and repeated explanations are omitted.

First Embodiment
1 is a schematic perspective view showing a fuel cell 1 according to a first embodiment. The fuel cell 1 according to the first embodiment comprises a fuel cell stack 2 and a manifold 3.

The fuel cell stack 2 is composed of a plurality of single cell batteries 21 stacked together. The single cell batteries 21 generate electricity by reacting hydrogen-containing gas with oxygen-containing gas, and are configured to cool the heat generated by the power generation with cooling water. For example, the single cell battery 21 has a polymer electrolyte membrane, an anode electrode and a cathode electrode arranged to sandwich the polymer electrolyte membrane, and a separator provided with a hydrogen-containing gas flow path in contact with the anode electrode, an oxygen-containing gas flow path in contact with the cathode electrode, and a cooling water flow path. In addition, the fuel cell stack 2 has a current collector that electrically connects adjacent single cell batteries 21 to each other. The fuel cell stack 2 has a structure in which a plurality of single cell batteries 21 are electrically connected in series.

The manifold 3 is arranged on the side of the fuel cell stack 2 in a direction perpendicular to the stacking direction of the single cell batteries 21. The manifold 3 is made of an insulating material to insulate the fuel cell stack 1 from the surroundings. Although FIG. 1 representatively shows one manifold 3 arranged on one side of the fuel cell stack 2, in reality, four manifolds 3 are arranged on the four side surfaces of the fuel cell stack 2.

The manifold 3 is provided with a supply port for supplying hydrogen-containing gas, oxygen-containing gas, or cooling water from the outside into the manifold 3, or a discharge port for discharging hydrogen-containing gas, oxygen-containing gas, or cooling water from the manifold 3 to the outside. The manifold 3 shown in FIG. 1 is provided with a discharge port 31 for discharging cooling water from the manifold 3 to the outside. The manifold 3 supplies the hydrogen-containing gas, oxygen-containing gas, or cooling water supplied to the inside of the manifold 3 through the supply port to the fuel cell stack 2, or discharges the hydrogen-containing gas, oxygen-containing gas, or cooling water discharged from the fuel cell stack 2 to the outside of the manifold 3 through the discharge port. The manifold 3 shown in FIG. 1 discharges the cooling water discharged from the fuel cell stack 2 to the outside of the manifold 3 through the discharge port 31. In the manifold 3 shown in FIG. 1, the portion 3a for discharging the cooling water is adjacent to the portion 3b for supplying or discharging another fluid (e.g., oxygen-containing gas) across a partition wall 3c.

To ensure insulation between the fuel cell 1 and the outside, the shortest flow path distance from the fuel cell stack 2, which is the power generation part of the fuel cell 1, to the supply port or the exhaust port is equal to or greater than the insulation distance. In the manifold 3 shown in FIG. 1, the distance (flow path length) of the shortest flow path 33 from the fuel cell stack 2 to the cooling water exhaust port 31 is equal to or greater than the insulation distance.

More specifically, inside the manifold 3, a flow path guide plate 32 is provided as an example of an insulating structure of the fuel cell 1 to make the shortest flow path distance equal to or greater than the insulation distance. The flow path guide plate 32 is made of an insulating material. The flow path guide plate 32 shown in FIG. 1 has a flat plate shape parallel to one side (the upper surface in FIG. 1) of the fuel cell stack 2. More specifically, the flow path guide plate 32 shown in FIG. 1 has both ends in the stacking direction of the single cell batteries 21 connected to the partition wall 3c and the side surface 3d of the manifold 3 facing the partition wall 3c, one end in a direction perpendicular to the stacking direction of the single cell batteries 21 connected to the side surface 3e of the manifold 3 on the exhaust port 31 side, and the other end in a direction perpendicular to the stacking direction of the single cell batteries 21 separated from the side surface 3f of the manifold 3 opposite the exhaust port 31.

However, the specific form of the flow path guide plate 32 is not limited to that shown in FIG. 1 and can be modified in various ways. For example, although one flow path guide plate 32 is provided in FIG. 1, the number of flow path guide plates 32 may be two or more.

According to the first embodiment, the shortest flow path distance of the hydrogen-containing gas, oxygen-containing gas, or cooling water inside the manifold 3 is equal to or greater than the insulation distance, so the fuel cell 1 can be insulated from the outside without connecting insulating piping made of insulating material to the manifold 3 for insulation. In addition, since insulating piping made of insulating material is no longer necessary, the number of piping connections can be reduced, which reduces the number of parts and the number of places where leaks occur. In addition, the volume of the insulating piping is reduced, so the amount of residual hydrogen-containing gas and oxygen-containing gas can be reduced.

In addition, according to the first embodiment, the simple configuration of the flow path guide plate 32 allows the shortest flow path distance of the hydrogen-containing gas, oxygen-containing gas, or cooling water to be greater than or equal to the insulation distance.

Second Embodiment
2 is a schematic perspective view showing a fuel cell 1 according to a second embodiment. In the following description, parts having the same or similar basic configurations as those in the first embodiment are given the same reference numerals and duplicated description will be omitted.

In the second embodiment, the flow path guide plate 32 is arranged to block the flow path of the hydrogen-containing gas, the oxygen-containing gas, or the cooling water. The flow path guide plate 32 shown in FIG. 2 is arranged to block the flow path of the cooling water. In the example shown in FIG. 2, both ends of the flow path guide plate 32 in the stacking direction of the single cell battery 21 are connected to the partition wall 3c and the side surface 3d of the manifold 3 facing the partition wall 3c, and both ends in the direction perpendicular to the stacking direction of the single cell battery 21 are connected to the side surface 3e of the manifold 3 on the exhaust port 31 side and the side surface 3f of the manifold 3 opposite the exhaust port 31. The flow path guide plate 32 is provided with a through hole that partially opens the flow path of the hydrogen-containing gas, the oxygen-containing gas, or the cooling water. The flow path guide plate 32 shown in FIG. 2 is provided with a through hole 321 that partially opens the flow path of the cooling water. The through hole is arranged away from the supply port or the exhaust port 31 in a direction perpendicular to the stacking direction of the single cell battery 21. The flow path guide plate 32 shown in FIG. 2 has one through hole 321, but the number of through holes 321 may be two or more.

The smaller the cross-sectional area of the flow path, the greater the electrical resistance, and therefore the shorter the flow path distance required for insulation. According to the second embodiment, the provision of the through holes 321 allows the cross-sectional area of the flow path to be reduced, thereby shortening the flow path distance required for insulation. This allows the manifold 3 to be made smaller and lighter.

Third Embodiment
3 is a schematic perspective view showing a fuel cell 1 according to a second embodiment. In the following description, parts having the same or similar basic configurations as those in the first embodiment are given the same reference numerals and duplicated description will be omitted.

In the third embodiment, the flow path guide plate 32 is integrally molded with the manifold 3.

According to the third embodiment, the manifold 3 and the flow path guide plate 32 are integrally molded, which reduces the number of parts and the labor required to attach the flow path guide plate 32. In addition, it is possible to prevent gas or water from passing through the contact area between the manifold 3 and the flow path guide plate 32, which may occur because the flow path guide plate 32 is a separate part from the manifold 3.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are within the scope of the invention and its equivalents as set forth in the claims, as well as the scope and gist of the invention.

1 Fuel cell, 2 Fuel cell stack, 21 Single cell battery, 3 Manifold, 31 Exhaust port, 33 Shortest flow path

Claims (8)

A fuel cell stack in which a plurality of single cell batteries are stacked;
a manifold disposed on a side of the fuel cell stack in a direction perpendicular to the stacking direction of the single cell batteries, the manifold supplying a hydrogen-containing gas, an oxygen-containing gas, or a cooling water to the inside of the manifold through a supply port provided in the manifold, or discharging the hydrogen-containing gas, the oxygen-containing gas, or the cooling water discharged from the fuel cell stack to the outside of the manifold through a discharge port provided in the manifold;
a shortest flow path distance from the fuel cell stack to the supply port or the exhaust port is equal to or greater than an insulation distance;
the manifold is made of an insulating material;
the manifold includes a flow path guide plate for making the shortest flow path distance equal to or greater than the insulation distance,
the flow path guide plate extends along a side surface of the fuel cell stack from one end on the fuel cell stack side to the other end on the supply port or the discharge port side,
The shortest flow path distance is a flow path distance from the fuel cell stack to the supply port or the discharge port via the flow path guide plate . The fuel cell according to claim 1, wherein the manifolds are disposed on four sides of the fuel cell stack in a direction perpendicular to the stacking direction of the single cell batteries. The fuel cell according to claim 1 , wherein a plurality of said flow path guide plates are provided. 4. The fuel cell according to claim 1, wherein the flow path guide plate is arranged so as to block the flow path of the hydrogen-containing gas, the oxygen-containing gas, or the cooling water, and has a through hole that partially opens the flow path. The fuel cell according to claim 4 , wherein a plurality of the through holes are provided. 6. The fuel cell according to claim 4 , wherein the through-hole is disposed away from the supply port or the discharge port in a direction perpendicular to the stacking direction. The fuel cell according to claim 1 , wherein the flow path guide plate is integrally formed with the manifold. A fuel cell stack in which a plurality of single cell batteries are stacked;
a manifold disposed on a side of the fuel cell stack in a direction perpendicular to the stacking direction of the single cell batteries, the manifold supplying a hydrogen-containing gas, an oxygen-containing gas, or a cooling water to the inside of the manifold through a supply port provided in the manifold, or discharging the hydrogen-containing gas, the oxygen-containing gas, or the cooling water discharged from the fuel cell stack to the outside of the manifold through a discharge port provided in the manifold,
An insulation structure of a fuel cell, the shortest flow path distance from the fuel cell stack to the supply port or the exhaust port being equal to or greater than an insulation distance,
the manifold is made of an insulating material;
the insulating structure includes a flow path guide plate for making the shortest flow path distance equal to or greater than the insulation distance;
the flow path guide plate extends along a side surface of the fuel cell stack from one end on the fuel cell stack side to the other end on the supply port or the discharge port side,
An insulating structure, wherein the shortest flow path distance is a distance of a flow path from the fuel cell stack to the supply port or the exhaust port via the flow path guide plate .

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