WO2006082911A1

WO2006082911A1 - Fuel cell stack

Info

Publication number: WO2006082911A1
Application number: PCT/JP2006/301813
Authority: WO
Inventors: Masaaki Kondo
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2005-02-01
Filing date: 2006-01-27
Publication date: 2006-08-10
Also published as: JP2008135188A

Abstract

[1] A fuel cell stack (23) includes: a pair of separators (18) having a cell module (19) and an impurities trap module (50) and electrically communicating at least at a part of opposing surfaces of the impurities track module (50); and a impurities removal body (51) arranged in a space between the pair of separators for removing impurities from a fluid. [2] The impurities trap module (50) is arranged at the fluid supply side end of the fuel cell stack. [3] The impurities trap module (50) is arranged at the end opposite to the fluid supply side end of the fuel cell stack. [4] The impurities removal body is an ion exchange resin. [5] The impurities removal body (51) captures impurities and holds the captured impurities. [6] The impurities trap module (50) has a pressure loss almost identical to that of the cell module (19).

Description

Specification

Fuel cell stack technology

The present invention relates to a stack of fuel cells (cells). Background art

A solid polymer electrolyte fuel cell (PEMFC) is composed of a stack of a membrane-electrode assembly (MEA) and a separator. MEA consists of an electrolyte membrane made of ion exchange membrane, an electrode (anode, fuel electrode) consisting of a catalyst layer placed on one side of this electrolyte membrane, and an electrode (force sword) made of a catalyst layer placed on the other side of the electrolyte membrane. Air electrode). The separator has a fluid passage for supplying fuel gas (hydrogen) and oxidizing gas (oxygen, usually air) to the anode and the power sword, and also has a refrigerant flow path for flowing the refrigerant. A diffusion layer is provided between ME A and Separeto. One or more cells are stacked to form a cell module, and cell modules are stacked to form a module group. Terminals, insulants, and end plates are placed at both ends of the module group in the stacking direction. The fuel cell stack is configured by fastening to a fastening member (eg, tension plate, tension port, etc.) extending in the module stacking direction on the outside of the module stack, and applying a tightening load to the module stack in the module stacking direction.

In solid polymer electrolyte fuel cells, the reaction that converts hydrogen into hydrogen ions and electrons occurs on the anode side, and the hydrogen ions move to the force sword side in the electrolyte membrane, and oxygen and hydrogen ions on the force sword side. And electrons (electrons generated at the anode of the adjacent MEA pass through the separator overnight, or electrons generated at the anode of the cell at one end of the cell stack pass through an external circuit to the cathode of the cell at the other end of the cell stack. Reaction to produce water from the anode side: H ₂ → 2 H + + 2 e " Force sword side: 2 H + + 2 e— + (1/2) 0 ₂ → H ₂ 0

In order for hydrogen ions to move through the electrolyte membrane, the electrolyte membrane needs to be moderately moistened. It was generated by the above power generation reaction in addition to supplying the cell stack with the reaction gas being appropriately humidified. Water is used to wet the electrolyte membrane.

Impurities (plumbing iron iron, pumping resin abrasion powder, etc.) in fluids such as reaction gas (fuel gas, oxidizing gas) and refrigerant supplied to the cell turn on in moisture contained in the gas flow. If they contain foreign materials that do not become ions or become foreign substances, they can cause deterioration of the fuel cell. For example, when ions attach to the hornworm medium, the catalyst performance decreases, and when they enter the electrolyte membrane (with ions in the hands of the molecules used for proton transfer), the proton movement in the membrane is inhibited, Japanese Patent Laid-Open No. 2 00 1-3 5 5 1 9 which deteriorates a fuel cell is equipped with an ion exchange resin outside the fuel cell stack in the cooling water system in order to keep the cooling water supplied to the cell clean. The thing is disclosed. However, removal of ions from the cooling water system does not reduce the ions in the humidified water in the reaction gas. Since an impurity removal device is provided in series with the fuel cell stack, the entire amount of cooling water can be removed from the impurity removal device. There are problems such as passing through and increasing the flow pressure loss.

Japanese Patent Laid-Open No. 2 0 3-3 3 8 3 0 5 discloses a fuel cell system in order to reduce impurities contained in a gas supplied to a cell and to reduce impurities in a stack. It discloses a fuel cell stack structure in which a cell (dummy cell) without an electrolyte membrane is provided at the end of the tack, and impurities are accumulated in the gas flow path of the dummy cell to reduce the impurities. However, the impurity reduction configuration of Japanese Patent Laid-Open No. 2 03-3-3 3 8 3 0 5 has the following problems.

(Ii) The above impurity reduction configuration does not actively take impurities, so there is a limit to the reduction of impurities, and further improvement in the purity of the fluid has been desired. (Mouth) The impurity reduction configuration described above does not actively retain the accumulated impurities, so once accumulated impurities may flow again in the fluid flow and circulate to the fuel cell. Disclosure of the invention

An object of the present invention is to provide a fuel cell stack that can positively adsorb or remove impurities from a fluid and desirably retain the adsorbed or trapped impurities at any time. The present invention for achieving the above object is as follows.

The fuel cell stack according to the present invention includes a cell module having a gas flow path, a void communicating with the gas flow path, and an impurity removing body for removing impurities from the fluid provided in the void. A trap module.

The fuel cell stack has a gas manifold, the gas manifold includes a gas supply manifold and a gas exhaust manifold, and the impurity trap module includes a gas supply manifold and a gas in the fuel cell stack. This layer communicates with the exhaust manifold. The fuel cell stack of the present invention has a cell module and an impurity trap module, and the impurity trap modules are opposed to each other to form a void therebetween, and are electrically connected to each other at least at a part of the opposed surface. A pair of separators, and an impurity remover provided in a space between the pair of separators and removing impurities from the fluid.

Preferably, an impurity trap module is provided at the end of the fuel cell stack on the fluid supply side.

Alternatively, an impurity trap module is provided at the fluid supply side end and the opposite end of the fuel cell stack.

Alternatively, the impurity trap module is provided at the fluid supply side end of the fuel cell stack and the end opposite to the fluid supply side end of the fuel cell stack.

The impurity removing body may be an ion exchange resin. The impurity removal body may capture impurities and hold the captured impurities. The impurity remover may include an ion exchange resin and one that traps impurities and retains the trapped impurities.

The impurity removing module includes an ion exchange resin and a substance that traps impurities and retains the trapped impurities, and the impurity trap module having the impurity removing body composed of the ion exchange resin supplies fluid to the fuel cell stack. An impurity trap module is provided at the end opposite to the fluid supply side end of the fuel cell stack, which is provided at the side end and has an impurity remover composed of an element that captures and retains the trapped impurity. May be.

Preferably, the impurity trap module has substantially the same pressure loss as the cell module. According to the fuel cell stack of the present invention, the stack has an impurity trap module, and the impurity trap module has an impurity remover that removes impurities from the fluid, so that impurities are accumulated in the fluid flow path like a conventional dummy cell, Impurities can be adsorbed or trapped in fluids more aggressively than those that precipitate. Further, by using an impurity removal body that can retain impurities, it is possible to prevent impurities once adsorbed or trapped from flowing back into the flow and flowing into the fuel cell.

When the impurity trap module connects the gas supply manifold and gas output manifold hold, even if condensed water accumulates in the communication part of the impurity trap module when power generation is stopped (when gas supply is stopped), Impurities can be reduced, and deterioration of the cell during power outage can be suppressed.

When the impurity trap module is provided at the fluid supply side end of the fuel cell stack, the impurity trap module can selectively and efficiently remove ions. Ions tend to selectively degrade the cells at the fluid supply end of the stack or a few cells from the fluid supply end (moisture contained in the gas stream passes through the manifold) Since it falls into the flow channel in the cell plane while passing 2 to 3 cells from the end cell, 2 to 3 ions from the end cell or end In-cell gas of the cell The impurity trap module can be removed selectively and efficiently by arranging the impurity trap module at the fluid supply side end of the stack (to flow into the flow path and degrade the cell). When installed at the end opposite to the fluid supply side end, the impurity trap module can selectively and efficiently remove foreign substances in the fluid. Foreign matter tends to selectively deteriorate the cells at the end opposite to the fluid supply side or two to three cells from the end opposite to the fluid supply end (included in the gas flow) Foreign matter flows through the manifold to the end opposite to the end on the fluid supply side, and flows into the cell on the side opposite to the end on the fluid supply side or into the in-cell gas flow path of two to three cells from the end. In order to degrade the cell), the impurity trap module is disposed at the end opposite to the fluid supply side of the fuel cell stack, so that foreign matters can be selectively and efficiently removed. If the impurity trap module is provided at the fluid supply side end of the fuel cell stack and the end opposite to the fluid supply side of the fuel cell stack, the impurities at the fluid supply side end of the fuel cell stack The trap module selectively and efficiently removes ions mixed in the moisture in the gas stream, and the impurity trap module at the end opposite to the fluid supply side of the fuel cell stack Remove foreign matter selectively and efficiently. This removes both ions and foreign matter.

When the impurity removing body is an ion exchange resin, ions contained in moisture in the gas stream are positively adsorbed and held on the ion exchange resin by ion exchange. Since holding is also performed, ions once adsorbed are prevented from flowing again and circulating to the cell. As a result, it is possible to supply a reaction gas with high purity. Impurity-removed bodies that have absorbed and retained ions and have reduced adsorption capacity are replaced with new ion exchange resins.

If the impurity remover is one that captures impurities and retains the trapped impurities (for example, non-woven cloth or breathable vapor), foreign substances in the gas flow are actively captured and retained. Since holding is also performed, ions once trapped are prevented from flowing again and circulating to the cell. As a result, it is possible to supply a reaction gas with high purity. Impurity-removed bodies whose trapping ability has been reduced by capturing and holding foreign substances are replaced with new impurity-removed bodies. When the impurity remover includes an ion exchange resin and a substance that traps impurities and retains the trapped impurities, the ions mixed in the moisture in the gas stream are adsorbed and retained by the ion exchange resin. Foreign matter contained in the flow is captured and retained by the one that captures and retains the captured impurities. As a result, it is possible to supply a high-purity reaction gas that contains almost no ions or foreign substances.

An impurity trap module having an impurity remover composed of an ion exchange resin is provided at the fluid supply side end of the fuel cell stack, and has an impurity remover composed of one that captures impurities and holds the captured impurities When the impurity trap module is installed at the end of the fuel cell stack opposite to the fluid supply side, the ions that are likely to flow through the trap module at the end of the stack on the fluid supply side The foreign matter that easily flows through the trap module on the opposite end of the stack to the fluid supply side can be effectively removed by trapping impurities and holding the trapped impurities.

When the impurity trap module has almost the same pressure loss as the cell module, the flow rate flowing through the trap module arranged in parallel with the cell module can be made substantially the same as the flow rate through each cell module. As a result, it is possible to prevent the flow rate of the cell module from flowing through the trap module and reducing the power generation performance, and to prevent the impurity removal performance from being deteriorated due to the flow of the trap module being too small. Brief Description of Drawings

The objects and features of the present invention will be further understood from the following description with reference to the drawings.

FIG. 1 is a side view of a fuel cell stack including an impurity trap module disposed at an end of a cell stack according to the present invention.

Fig. 2 is a cross-sectional view of the fuel cell stack of Fig. 1 at the impurity trap module. FIG. 3 is a cross-sectional view of the impurity trap module of the fuel cell stack in the case where the impurity removing body in FIG. 2 is made of a granular ion exchange resin placed in a porous container. Fig. 4 is a front view of the fuel cell stack of Fig. 1 in the impurity trap module.

FIG. 5 is a sectional view of the impurity trap module of the fuel cell stack, showing the energization site in FIG.

FIG. 6 is a side view of a fuel cell stack including an impurity trap module disposed at an end of a cell stack and an intermediate portion in the cell stacking direction according to the present invention.

FIG. 7 is an enlarged cross-sectional view of a part of the cell module portion of the fuel cell stack of FIGS.

FIG. 8 is a front view of the cell module portion of the fuel cell stack of FIGS. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the fuel cell stack of the present invention will be described with reference to FIGS.

The fuel cell applied to the fuel cell stack of the present invention is, for example, a solid polymer electrolyte fuel cell 10. The fuel cell (cell) 10 is mounted on, for example, a fuel cell vehicle. However, it may be used for other than automobiles.

As shown in FIGS. 1, 7, and 8, the solid polymer electrolyte fuel cell 10 is composed of a laminate of a membrane-electrode assembly (MEA) and a separator 18. ME A was placed on the electrolyte membrane 1 1 made of ion exchange membrane and electrode 1 4 (anode, fuel electrode) made of catalyst layer placed on one side of electrolyte membrane 1 1 and on the other side of electrolyte membrane 1 1 It consists of an electrode 17 consisting of a catalyst layer (force sword, air electrode). In the separate evening 18, gas flow paths 2 7, 2 8 (fuel gas flow path 2 7 for supplying fuel gas (hydrogen) and oxidizing gas (oxygen, usually air) to the electrodes 14, 1 7 In addition, an oxidizing gas channel 2 8) and a cooling water channel 26 through which cooling water for cooling the fuel cell flow are formed. Between MEA and Separation 1 8 there is a diffusion layer 13 on the anode side and a diffusion layer 16 on the force sword side. It is. ME A and separator plate 18 are stacked to form a cell, and the cell module 19 is formed by stacking at least one layer of the cell, and the cell module 19 is stacked to form a cell stack (referred to as a module stack). And at an appropriate location in the cell stacking direction of the cell stack (for example, at least one of the fluid supply side end, the fluid supply side end opposite to the end of the cell stack, and the intermediate portion of the cell stack) An impurity trap module 50 that does not contribute to power generation, which will be described later, is disposed. Then, the terminal 20, the insulative evening 21, and the end plate 2 2 are arranged at both ends of the cell stack including the impurity trap module 50 in the cell stack direction, and the end plate 22 at both ends is connected to the cell stack. Tighten to the fastening member 24 (ex. Tension plate, tension port, etc.) that extends in the cell stacking direction with a port 25 nut, and apply a tightening load to the cell stack in the module stacking direction (for example, one end A pressure plate is installed between the end plate and the inner side of the plate, a spring is placed between the end plate and the pressure plate plate at one end, and the spring force is adjusted to adjust the module stacking direction to the cell stack. The tightening load is applied to the fuel cell stack 2 3.

In the cell 10, the electrolyte membrane 11 is made of a solid polymer membrane ion exchange membrane, and hydrogen ions (protons) move through the membrane in a wet state. The electrolyte membrane 11 is a non-conductive membrane. The catalyst layers 12 and 15 are made of platinum (Pt), carbon (C), and an electrolyte. The diffusion layers 1 3 and 16 have gas permeability and are made of a single bond (C).

Separator evening 18 separates either fuel gas and oxidizing gas, fuel gas and cooling water, or oxidizing gas and cooling water, and between adjacent cells, electrons flow from the anode of the adjacent cell to the cathode. An electric passage is formed.

Separetsu 18 is impervious to gas and water and has electrical conductivity. Separator 18 is usually made of either one of force (including the case of graphite), metal (metal), or conductive resin.

A fuel gas flow path 27 is formed in the separation side on one side of the MEA, and an oxidizing gas flow path 28 is formed in the separation side on the other side of the MEA. The cooling water channel 26 is provided for each cell or for each of a plurality of cells. In the example of Fig. 7, 1 module 1 9 is configured with 1 cell 1 0. The cooling water channel 26 is provided between the modules. In addition, the portion of the cell 10 where the MEA is provided and the fuel gas and the oxidizing gas are supplied to both sides thereof constitutes a power generation unit 34 of the fuel cell.

The Separeto 18 usually has a square shape or a substantially square shape. However, the shape of Separation 18 is not limited to a square.

The gas flow paths 27, 28 (fuel gas flow path 27, oxidant gas flow path 28) have a plurality of protrusions within the width of the groove group or the flow path group in which a plurality of flow grooves are parallel. It consists of a flow path. The gas flow path may be formed in a so-called serpentine flow path formed so as to meander in the in-plane direction of the separator by the partition wall.

In the separate night 18, a cooling water manifold 29, a fuel gas manifold 30, and an oxidant gas manifold 31 are formed at opposite ends across the power generation unit 34. These manifolds 29, 30 and 31 are sealed together so that different fluids do not mix. Separate separators on both sides of ME A are usually sealed with adhesive 33, and adjacent cells are usually sealed with gasket 32. In FIG. 1, pipes 3 6, 3 7 and 3 8 for supplying and discharging cooling water, fuel gas and oxidizing gas are connected to manifolds 29, 30 and 31, respectively. As shown in FIG. 1, the cooling water, the fuel gas, and the oxidizing gas are discharged from the hole of the end plate 22 at one end of the fuel cell stack 23 in the cell stacking direction. That is, the stack end on the fluid supply side and the stack end on the fluid discharge side are at the same stack end. Fluid (reactive gas, cooling water) flows into the stack from one end of the stack, makes a U-turn at each cell 10 and trap module 50, and flows out from the same stack end as the inflow side. Each cell 10 and the trap module 50 are parallel to each other in terms of flow path.

Piping 3 6, 3 7 and 3 8 are made of stainless steel piping, and have a valve and a circulation pump on the way. 鎗 (A small amount of acid (hydrofluoric acid, sulfuric acid) dissolves from the electrolyte, so the moisture in the gas becomes acidic. Easy to wear even in the case of stainless steel) and bearings such as coating powder (which often contains fluorine in the case of resin) are mixed in, and moisture in the gas (due to humidification gas) The hydrogen system is partially circulated, so the generated water circulates, so there is moisture ) And cooling water, they become ions (for example, iron ions and fluorine ions) and may be foreign matter. Cell 10 hates impurities made up of ions and foreign matter.

In the inventors' tests, it has been discovered that the poisoning of cells by impurities (decreased power generation performance) is concentrated in the cells 10 at specific sites.

In the case of ions, the cells 10 on the gas-filled end of the stack 23 are likely to be poisoned or the cells 10 to 2 to 3 from the gas-filled end. This is presumably because water containing ions falls into the cell flow path (or flows in by gas flow) in the first 1 to 3 cells while passing through the manifold.

In the case of foreign substances that are not ions, the mass is larger than that of mist containing ions, so the inertia flows through the manifold until it reaches the end of the manifold on the opposite side of the gas inlet. Since the U-turn is made through the gas flow path of a cell on the opposite side of the gas-filled end or a few cells close to that cell, the cell on the opposite side of the gas-filled end or its cell A few cells close to are poisoned intensively. As shown in FIGS. 1 to 6, in order to prevent or suppress performance degradation due to impurities in the cells 10 of the stack 23, the fuel cell stack 23 of the present invention includes a cell module 10 having a gas flow path and An impurity trap module 50 having an empty space 52 communicating with the gas flow path and having an impurity removing body 51 for removing impurities from the fluid provided in the empty space 52 is provided.

The fuel cell stack 23 of the present invention has a cell module 10 and at least one impurity trap module 50. The impurity trap module 50 is provided so as to form a parallel flow path with the cell module 10.

The fuel cell stack 23 has a fuel gas manifold 30 and an oxidizing gas manifold 31. Gas manifolds 30 and 31 are fuel cell stacks 2 3. All cells 10 and impurity trap module 50 and fuel cell stack 23. Evening 2 1 and end plate 2 2 are penetrated in the cell stacking direction. It extends. Gas manifolds 3 0 and 3 1 are connected to pipes 3 7 and 3 8. The fuel gas manifold 30 and the oxidizing gas manifold 31 are formed in each cell 10 and also in the impurity trap module 50. The fuel gas manifold 30 and the oxidizing gas manifold 31 of each cell 10 and the impurity trap module 50 include a gas supply manifold and a gas exhaust manifold, respectively. The gas flow paths 2 7 and 2 8 of the cell 10 communicate the gas supply manifold and the gas discharge manifold formed in the cell. Further, a void (also referred to as a gap) 52 formed in the impurity trap module 50 communicates the gas supply manifold and the gas exhaust manifold. The impurity trap module 50 is a layer that connects the gas supply manifold and the gas discharge manifold formed in the impurity trap module 50. Impurity removal body (impurity removal body may be referred to as impurity removal body material) 5 1 is arranged in void (gap) 5 2 of impurity trap module 50.

Impurity trap module 50 is opposed to each other, and a space (gap) 52 is provided between the separators (between a pair of separators), and is electrically connected to at least part of the opposing surface. (53 indicates a conductive part. The conductive part 53 is not coated with an electrical insulating material, and a pair of separators are in direct contact with each other or through a conductive material.) Provided in a space (gap) 5 2 between a pair of separate evenings 18 and a pair of separate evenings 18, impurities (ions or ions) from fluid (gas containing moisture, cooling water) Impurity removal body for removing (foreign matter) (impurity removal body may be referred to as impurity removal body material) 5 1. The cell module 19 is electrically isolated by the electrolyte membrane 11 and the adhesive 33, while the impurity trap module 50 is a pair of conducting parts. 5 3 are connected to each other. Without this conducting portion 53, the impurity trap module 50 provided at the stack end portion electrically cuts off the cell module 19 and the terminal 20 on both sides, and the fuel cell stack is not established. Impurity removal body 5 1 Separation on both sides of 1 18 Fluid flow path 2 6, 2 7, 2 8 (Flow path through which fluid same as fluid flow path 2 6, 2 7, 2 8 of cell 10) The impurity is removed while the fluid flows through the fluid flow paths 2 6, 2 7 and 2 8 of the impurity trap module 50. The impurities in the fluid are positively adsorbed or trapped on the impurity removing body 51 and retained and removed by making sufficient contact with the dead body 51. The fluid flow paths 2 6, 2 7 and 2 8 of the impurity trap module 50 communicate with the fluid manifolds 2 9, 3 0 and 3 1 of the stack 2 3, respectively.

As shown in Fig. 2, Fig. 4, and Fig. 5, when one impurity trap module 50 is provided at one end of the stack 23, the impurity removal for removing impurities in the fuel gas is performed in one impurity trap module 50. The body 51 and the impurity removing body 51 for removing the impurities of the oxidizing gas are provided in different locations in the same cell plane. However, two impurity trap modules 50 are provided, and only one impurity remover 51 for removing fuel gas impurities is provided on the cell surface of one trap module 50, and fuel is provided on the cell surface of the other trap module 50. It is advisable to provide only an impurity remover 51 that removes gas impurities.

As shown in FIGS. 1 and 6, the impurity trap module 50 is provided at least at the fluid supply side end of the fuel cell stack 23.

Further, it is desirable that the impurity trap module 50 is also provided at the end of the fuel cell stack 23 opposite to the end of the fluid supply side.

As shown in FIG. 1 and FIG. 6, the impurity trap module 50 is attached to both ends of the fluid supply side end of the fuel cell stack 23 and the end opposite to the fluid supply side of the fuel cell stack. It is desirable to be provided.

In the example of FIG. 6, at least one impurity trap module 50 is also provided in the middle part of the fuel cell stack 23 in the cell stack direction (a plurality of impurity trap modules 50 are provided in the middle part of the stack). May also be provided).

The impurity remover 51 may be an ion exchange resin that adsorbs and holds impurities made of ions. When the impurity-removing body 51 is made of an ion exchange resin, the ion exchange resin may be formed into a sheet shape or a plate shape as shown in FIG. Alternatively, as shown in FIG. 3, it may be formed into a plurality of particles, placed in a porous container 54, and mounted in a space (gap) 52. The impurity-removed body 51 may be one that captures impurities made of foreign substances that are not ions and retains the captured impurities (for example, a nonwoven fabric or a vapor).

When the impurity remover 51 is provided at a plurality of locations of the stack 23, the impurity remover 51 provided at a certain location may be an ion exchange resin that adsorbs and retains impurities made of ions. The impurity removing body 51 provided at the location may be one that captures impurities composed of foreign matters that are not ions and retains the captured impurities (for example, a nonwoven fabric).

When the impurity remover 51 includes an ion exchange resin and a substance that captures and traps impurities (for example, a nonwoven fabric or a vapor), the impurity remover 5 made of an ion exchange resin 5 The impurity trap module 50 having 1 is preferably provided at the fluid supply side end of the fuel cell stack 23 (because the cell at the fluid supply side end is deteriorated by ions) and traps impurities. An impurity trap module 50 having an impurity removal body 51 made of a material that holds trapped impurities (for example, a nonwoven fabric or a vapor) has a cell on the opposite end to the fluid supply side end. Preferably, it is provided at the end of the fuel cell stack opposite to the end of the fluid supply side.

The impurity trap module 50 has almost the same pressure loss as the cell module 10. Therefore, even if the impurity trap module 50 is inserted into the stack 23, the flow rate of the fluid flowing through each cell 10 is hardly changed. Next, functions and effects of the fuel cell stack 23 of the present invention will be described.

In the fuel cell stack of the present invention, the fuel cell stack 23 has an impurity trap module 50, and the impurity trap module 50 removes impurities from a fluid (fuel gas, oxidizing gas, cooling water). Since it has 5 1, it is more active than the conventional dummy cell (Japanese Patent Laid-Open No. 2 0 3-3 3 8 3 0 5) in which impurities are simply accumulated and precipitated in the fluid flow path. Impurities from the fluid can be removed by adsorption or trapping.

In addition, by using an impurity remover 51 that can hold impurities, It is possible to prevent or suppress impurities adsorbed or trapped from flowing out into the flow again and flowing into the fuel cell 10.

The impurity trap module 50 makes the gas supply manifold and the gas discharge manifold communicate with each other through the impurity removing body 51. When the impurity trap module 50 is located at the end on the front side of the gas introduction direction in the cell stacking direction, most of the condensed water that has traveled along the inner wall surface of the gas pipes 37, 38 is transferred to the impurity trap module 50. Inflow, power generation cell

Without flowing into 10, it is directly discharged from the cell stack through the gas outlet manifold. In other words, the impurity trap module 50 has gas self-pipe 3 7 and 3

It plays the role of cutting the condensate supplied from 8. Conversely, when the impurity trap module 50 is located at the end of the cell stack on the back side in the gas introduction direction, the condensed water that travels along the inner wall surface of the gas supply manifold is supplied to the power generation cell on the back side. It can be suppressed.

Condensed water may accumulate in the communication part of the impurity trap module 50 when power generation is stopped (when gas supply is stopped). However, according to the present invention, impurities can be reduced from the condensed water that is stored during power generation stop. It is possible to suppress the deterioration of the power generation cell. The gas supplied to the power generation cell 10 is, for example, a gas humidified with moisture contained in the off-gas, and condensed water is likely to be generated. Therefore, the present invention is particularly effective.

If the impurity trap module 50 is provided at the fluid supply side end of the fuel cell stack 23 (including the impurity remover 51 made of ion exchange resin), the impurity trap module 50 Can selectively and efficiently remove ions contained in the fluid (for example, iron ions and fluorine ions that may be dissolved in moisture in the gas). The ions tend to selectively degrade 2 to 3 cells 10 from the fluid supply side end of the stack 2 3 at the fluid supply side end (the moisture contained in the gas flow is The cell that is passing through the second hold or drops from the end to the in-cell flow path while passing 2 to 3 cells from the end. 2 to 3 cells flow into the in-cell gas flow path and deteriorate the cell) by placing the impurity trap module 50 at the fluid supply side end of the stack 23 Can be removed selectively and efficiently.

When the impurity trap module 50 is provided at the end opposite to the fluid supply side end of the fuel cell stack (including the impurity removing body 51 for removing foreign matter), the impurity trap module 50 It is possible to selectively and efficiently remove foreign matter (non-ionized, relatively large foreign matter) inside. The foreign matter tends to selectively deteriorate the cell 10 at the end opposite to the fluid supply end or two to three cells 10 from the end opposite to the fluid supply end (gas Foreign matter contained in the flow flows through the manifold to the end opposite to the end on the fluid supply side, or within the cell plane of 2 to 3 cells from the end opposite to the end on the fluid supply side. The impurity trap module 50 is arranged at the end opposite to the fluid supply side of the fuel cell stack 2 3 so that the foreign matter is selectively and It can be removed efficiently.

If the impurity trap module 50 is installed at the fluid supply side end of the fuel cell stack 23 and at the end opposite to the fluid supply side end of the fuel cell stack 23, the fuel cell stack Impurity trap module 50 at the end of fluid supply (impurity removal body of this trap module is preferably made of ion exchange resin) selectively and efficiently removes ions mixed in moisture in gas flow Remove the impurity trap module 50 at the end opposite to the fluid supply side of the fuel cell stack 23 (the impurity removal body of this trap module is preferably a foreign matter removal method). Are removed selectively and efficiently. As a result, both ions and foreign substances can be removed.

When the impurity removing body 51 is an ion exchange resin, ions contained in moisture in the gas flow are positively adsorbed and held on the ion exchange resin by ion exchange. Since retention is also performed, ions once adsorbed are prevented from flowing again and circulating to the cell. As a result, it is possible to supply a reaction gas with high purity. Impurity-removed bodies that have reduced adsorption capacity due to adsorption and retention of ions are replaced with new ion exchange resins.

If the impurity remover 51 is one that captures impurities and retains the trapped impurities (for example, non-woven fabric or breathable vapor), foreign matter in the gas flow touches the surface of the non-woven fabric ( It is even more actively captured and retained. Also hold Therefore, the ions once trapped are prevented from flowing again and circulating to the cell. As a result, it is possible to supply a reaction gas with high purity. Impurity-removed bodies whose trapping ability has been reduced by capturing and holding foreign substances are replaced with new impurity-removed bodies.

If the impurity remover 51 contains an ion exchange resin and something that captures and retains impurities (for example, non-woven fabric or breathable vapor), it will be mixed with moisture in the gas stream. Ions are adsorbed and retained by the ion exchange resin, and foreign substances contained in the gas flow are captured and retained by those that capture the impurities and retain the captured impurities (for example, nonwoven fabric or breathable paper). Is done. As a result, it is possible to supply a highly pure reaction gas containing almost no ions or foreign substances.

Impurity trap module 50 having impurity remover 51 made of ion exchange resin is provided at the fluid supply side end of fuel cell stack 23 to capture and retain the trapped impurity ( For example, an impurity trap module 50 having an impurity removing body 51 made of a nonwoven fabric or a breathable vapor is provided at the end opposite to the fluid supply side end of the fuel cell stack 23. In this case, ions that tend to flow through the trap module 50 at the end of the fluid supply side of the stack 23 can be effectively removed by the ion exchange resin, and the end opposite to the end of the fluid supply side of the stack 23 That traps impurities and retains them (for example, non-woven fabric) By the over-Pas) base breathable go-between can be effectively removed.

The impurity trap module 50 forms a parallel path with the cell module 10 and has almost the same pressure loss as each cell module 10, so the flow rate of the trap module 50 placed in parallel with the cell module 10 Can be made substantially the same as the flow rate flowing through each cell module 10. As a result, it is possible to prevent the flow rate of the cell module 10 from decreasing due to excessive flow to the trap module 50 and reducing the power generation performance of the cell module, and the flow of the trap module 50 is too small to remove impurities. Can be prevented from decreasing.

Claims

The scope of the claims

1. a cell module having a gas flow path;

An impurity trap module having a void communicating with the gas flow passage inside, and an impurity removing body for removing impurities from the fluid provided in the void;

A fuel cell stack comprising:

2. The fuel cell stack includes a gas manifold, the gas manifold includes a gas supply manifold and a gas discharge manifold, and the impurity trap module includes the gas supply manifold of the fuel cell stack. 2. The fuel cell stack according to claim 1, wherein the fuel cell stack is a layer communicating with the gas exhaust manifold.

3. With cell module,

An impurity trap module;

Have

The impurity trap module is

A pair of separate evenings that form a void in opposition to each other and that are electrically connected to each other on at least a part of the opposing surface;

An impurity removing body provided in the space between the pair of separators for removing impurities from the fluid;

Including fuel cell stack.

4. The fuel cell stack according to claim 1, wherein the impurity trap module is provided at a fluid supply side end of the fuel cell stack.

5. The fuel cell stack according to claim 1 or 3, wherein the impurity trap module is provided at an end opposite to the fluid supply side of the fuel cell stack.

6. The impurity trap module is provided at a fluid supply side end of the fuel cell stack and a fluid supply side end opposite to the fluid supply side end of the fuel cell stack. The fuel cell stack according to item.

7. The fuel cell stack according to claim 1 or 3, wherein the impurity removing body is an ion exchange resin.

8. The fuel cell stack according to claim 1 or 3, wherein the impurity removing body captures impurities and holds the captured impurities.

9. The fuel cell stack according to claim 1 or 3, wherein the impurity removing body includes an ion exchange resin and a substance that traps impurities and retains the trapped impurities.

10. The impurity remover includes an ion exchange resin and an impurity trapping and retaining the trapped impurity, and an impurity trap module having an impurity remover composed of the ion exchange resin is provided in the fuel cell stack. An impurity trap module having an impurity remover, which is provided at the end of the fluid supply side and has an impurity remover configured to capture impurities and hold the trapped impurities, is located at the end of the fuel cell stack opposite to the end of the fluid supply side. The fuel cell stack according to claim 1 or 3, wherein the fuel cell stack is provided.

11. The fuel cell stack according to claim 1, wherein the impurity trap module has substantially the same pressure loss as the cell module.