JP2016225284A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell having higher durability of a separator than a conventional fuel cell.SOLUTION: An electrode opposing region 144 of a separator 140 facing an electrode 120 includes a plurality of conductive portions 145, and a plurality of high resistance portions 146 having higher resistance than the plurality of conductive portions 145 and electrically separating each of the plurality of conductive portions 145. The separator 140 is formed using a base material made of a metal material. The plurality of high resistance portions 146 are formed by oxidizing a part of the base material. Therefore, the plurality of high resistance portions 146 are made of oxides of the base material generated by oxidizing a part of the base material. The plurality of conductive portions 145 are composed of a base material. This makes it possible to increase the durability of the separator, as compared with the case of forming the separator by joining the members constituting the plurality of conductive portions and the members constituting the plurality of high resistance portions.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a fuel cell.

  Patent Document 1 discloses a fuel cell in which a region of a separator facing an electrode is divided into a plurality of conductive regions. In the fuel cell of Patent Document 1, a plurality of conductive regions are formed of a conductive material, a portion that partitions the plurality of conductive regions is formed of a nonconductive material, and two of a conductive material and a nonconductive material are used. The members are joined and integrated.

  According to this, since the region facing the electrode in the separator is divided into a plurality of conductive regions, by measuring the current flowing through each of the plurality of conductive regions, the power generation surface of the fuel cell Current distribution can be measured.

JP2013-30471A

  However, in the conventional fuel cell described above, since the separator is formed by integrating the two members of the conductive material and the non-conductive material, thermal stress is applied to the joint surface between the two members during the cooling cycle, and the joint surface There is a risk of cracking. If a crack occurs in the joint surface between the two members, leakage of the reaction gas (fuel gas or oxidant gas) occurs from there. As described above, in the conventional fuel cell, there is a high possibility that cracks are generated in the separator due to thermal stress, and the durability of the separator is low.

  In view of the above points, an object of the present invention is to provide a fuel cell having a separator having higher durability than the above-described conventional fuel cell.

In order to achieve the above object, in the invention described in claim 1,
An electrolyte (110);
A cathode side electrode (120) and an anode side electrode (130) provided on both sides of the electrolyte;
A cathode side separator (140, 180) provided on the opposite side of the cathode side electrode from the electrolyte side and having a flow path (141c) for an oxidant gas supplied to the cathode side electrode;
An anode separator (150) provided on the opposite side of the anode side electrode from the electrolyte side and having a fuel gas flow path (153c) supplied to the anode side electrode;
At least one of the anode-side separator and the cathode-side separator has a plurality of conductive portions (145) higher than the plurality of conductive portions in the electrode facing region (144, 154) facing the anode-side electrode or the cathode-side electrode. A high resistance portion (146) that separates each of the plurality of conductive portions;
At least one of the separators is composed of a base material made of a metal material,
The plurality of conductive parts are made of a base material,
The high resistance portion is characterized by being composed of an oxide of a base material.

In the invention according to claim 2,
The electrolyte (110), the cathode side electrode (120) and anode side electrode (130) provided on both sides of the electrolyte, and the oxidation provided on the opposite side of the cathode side electrode from the electrolyte side and supplied to the cathode side electrode A cathode separator (140) having a flow path (141c) for the agent gas, and an anode having a flow path (153c) for the fuel gas provided on the opposite side of the anode side electrode from the electrolyte side and supplied to the anode side electrode A plurality of cells (10a) having a side separator (150) and stacked on each other;
Comprising at least one current sensor (13) laminated with a plurality of cells and electrically connected in series with the plurality of cells;
One current sensor has a plurality of current measuring units (13a) in contact with adjacent cells,
The separator adjacent to the current sensor among the anode-side separator and the cathode-side separator of each of the plurality of cells has a plurality of conductive portions (145) in the electrode facing region (144, 154) facing the anode-side electrode or the cathode-side electrode. And a high resistance portion (146) that is higher in resistance than the plurality of conductive portions and separates each of the plurality of conductive portions,
Each of the plurality of conductive parts is electrically connected to any one of the plurality of current measurement parts.
The separator adjacent to the current sensor is composed of a base material made of a metal material,
The plurality of conductive parts are made of a base material,
The high resistance portion is characterized by being composed of an oxide of a base material.

  According to the first and second aspects of the invention, the electrode facing region of the separator is divided into a plurality of conductive portions, and by measuring the current flowing through each of the plurality of conductive portions, the power generation surface of the fuel cell The current distribution within can be measured. Furthermore, since a part of one member constituting the separator is oxidized (chemical change) to form a high resistance portion, compared to the case where the separator is formed by joining and integrating the two members, Generation of cracks due to thermal stress can be suppressed.

  Therefore, according to the first and second aspects of the invention, a fuel cell having high separator durability can be provided.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

It is a figure showing the whole fuel cell system composition in a 1st embodiment. It is a perspective view of the fuel cell in a 1st embodiment. FIG. 3 is a plan view of the current sensor in FIG. 2. It is sectional drawing of the 1st cell in 1st Embodiment, and a current sensor. It is a top view of the cathode side separator of the 1st cell in a 1st embodiment. It is sectional drawing of the 2nd cell and current sensor in 1st Embodiment. It is sectional drawing of the 1st cell and current sensor in 2nd Embodiment. It is sectional drawing of the 1st cell and current sensor in 3rd Embodiment. It is sectional drawing of the 1st cell and current sensor in 4th Embodiment. It is sectional drawing which shows the manufacturing process of the current sensor in 4th Embodiment. It is sectional drawing which shows the manufacturing process of the current sensor in 4th Embodiment. It is a top view of the cathode side separator of the 1st cell in other embodiments.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
First, a fuel cell system including the fuel cell 10 of the present embodiment shown in FIG. 1 will be described. This fuel cell system is applied to a so-called fuel cell vehicle, which is a kind of electric vehicle, and supplies electric power to an electric load such as an electric motor for driving a vehicle, a secondary battery, and various auxiliary machines for vehicles (not shown). It is.

  The fuel cell 10 generates electric power by utilizing an electrochemical reaction between hydrogen and oxygen. In the present embodiment, a solid polymer electrolyte type is used as the fuel cell 10.

  The fuel cell 10 is configured by electrically connecting a plurality of fuel cell cells 10a (hereinafter simply referred to as cells 10a) as basic units. In each cell 10a, as shown below, hydrogen and oxygen are electrochemically reacted to output electric energy.

(Negative electrode side) H2 → 2H ++ 2e−
(Positive electrode side) 2H ++ 1 / 2O2 + 2e− → H2O
The electric energy output from the fuel cell 10 is measured by a cell monitor 11 that detects a voltage output from each cell 10a of the fuel cell 10 and a current sensor 12 that detects a current output as the fuel cell 10 as a whole. . Note that detection signals from the cell monitor 11 and the current sensor 12 are input to a control device 50 described later.

  Further, on the air electrode (positive electrode, cathode side electrode) side of the fuel cell 10, an air supply pipe 20 a for supplying air (oxygen) as an oxidant gas to the fuel cell 10, and the fuel cell 10 An air discharge pipe 20b for discharging the surplus air after the chemical reaction and the generated water generated at the air electrode from the fuel cell 10 to the outside air is connected.

  An air pump 21 is provided at the most upstream portion of the air supply pipe 20a to pump air sucked from the atmosphere to the fuel cell 10, and an air discharge pipe 20b adjusts the pressure of the air in the fuel cell 10. An air pressure regulating valve 23 is provided.

  Further, the air supply pipe 20 a and the air discharge pipe 20 b are provided with a humidifier 22 for moving the humidity (water vapor) of the air flowing out from the air pressure regulating valve 23 to the air pumped from the air pump 21. . The humidifier 22 functions to humidify the air supplied to the fuel cell 10.

  On the hydrogen electrode (negative electrode, anode side electrode) side of the fuel cell 10, a hydrogen supply pipe 30a for supplying hydrogen, which is a fuel gas, to the fuel cell 10, the generated water accumulated on the hydrogen electrode side is fueled with a small amount of hydrogen. A hydrogen discharge pipe 30b for discharging from the battery 10 to the outside air is connected. Furthermore, the hydrogen supply pipe 30a and the hydrogen discharge pipe 30b are connected via a hydrogen circulation pipe 30c.

  A high-pressure hydrogen tank 31 filled with high-pressure hydrogen is provided at the most upstream portion of the hydrogen supply pipe 30a, and is supplied to the fuel cell 10 between the high-pressure hydrogen tank 31 and the fuel cell 10 in the hydrogen supply pipe 30a. A hydrogen pressure regulating valve 32 for adjusting the pressure of hydrogen is provided.

  The hydrogen discharge pipe 30b is provided with an electromagnetic valve 34 that opens and closes at predetermined time intervals in order to discharge the produced water together with a small amount of hydrogen to the outside air. In the above-described electrochemical reaction, generated water is not generated on the hydrogen electrode side, but generated water that has permeated the electrolyte membrane of each cell 10a from the oxygen electrode side may accumulate on the hydrogen electrode side. Therefore, in this embodiment, the hydrogen discharge pipe 30b and the electromagnetic valve 34 are provided.

  The hydrogen circulation pipe 30c is provided to connect the downstream side of the hydrogen pressure regulating valve 32 of the hydrogen supply pipe 30a and the upstream side of the electromagnetic valve 34 of the hydrogen discharge pipe 30b. Thereby, the unreacted hydrogen flowing out from the fuel cell 10 is circulated to the fuel cell 10 and re-supplied. Further, a hydrogen pump 33 for circulating hydrogen in the hydrogen flow path 30 is disposed in the hydrogen circulation pipe 30c.

  By the way, the fuel cell 10 needs to be maintained at a constant temperature (for example, about 80 ° C.) during operation in order to ensure power generation efficiency. Therefore, a cooling water circuit 40 for cooling the fuel cell 10 is connected to the fuel cell 10. The coolant circuit 40 is provided with a water pump 41 that circulates coolant (heat medium) in the fuel cell 10 and a radiator 43 that includes an electric fan 42.

  Further, the cooling water circuit 40 is provided with a bypass flow path 44 through which the cooling water flows so as to bypass the radiator 43. A flow path switching valve 45 for adjusting the flow rate of the cooling water flowing through the bypass flow path 44 is provided at the junction of the cooling water circuit 40 and the bypass flow path 44. The cooling capacity of the cooling water circuit 40 is adjusted by adjusting the valve opening degree of the flow path switching valve 45.

  Further, a temperature sensor 46 as a temperature detecting means for detecting the temperature of the cooling water flowing out from the fuel cell 10 is provided in the vicinity of the outlet side of the fuel cell 10 in the cooling water circuit 40. By detecting the cooling water temperature by the temperature sensor 46, the temperature of the fuel cell 10 can be indirectly detected. The detection signal of the temperature sensor 46 is also input to the control device 50.

  The control device 50 controls the operation of various electric actuators constituting the fuel cell system on the basis of input signals, and is composed of a well-known microcomputer comprising a CPU, ROM, RAM, etc. and its peripheral circuits. Yes.

  Specifically, a current signal output from a current detection circuit 51 described later is input to the input side of the control device 50 in addition to the detection signals of the cell monitor 11, the current sensor 12, and the temperature sensor 46 described above. . On the other hand, on the output side, various electric actuators such as the air pump 21, the air pressure regulating valve 23, the hydrogen pressure regulating valve 32, the hydrogen pump 33, the electromagnetic valve 34, the water pump 41, and the flow path switching valve 45 are connected. Yes.

  As shown in FIG. 2, the fuel cell 10 includes a plurality of current sensors 13. The plurality of current sensors 13 measure the current flowing through the fuel cell 10 and are electrically connected to the control device 50 via a current detection circuit 51 as shown in FIG.

  The current sensor 13 is disposed adjacent to the cell 10a. In the present embodiment, a plurality of current sensors 13 are stacked together with a plurality of cells 10a, and the plurality of current sensors 13 and the plurality of cells 10a are electrically connected in series. The plurality of current sensors 13 are arranged between the adjacent cells 10a and the ones arranged adjacent to the cells 10a located at the end in the stacking direction among the stacked cells 10a. is there.

  As shown in FIG. 3, the current sensor 13 is configured by a plate-like member 13b in which a plurality of current measuring units 13a are integrally formed. The current measuring unit 13a is for measuring a current flowing in the stacking direction of the plurality of cells 10a.

  The current measuring unit 13a has the same configuration as that described in JP 2012-248305 A. That is, as shown in FIG. 4, the current measurement unit 13a includes a pair of electrode portions 13c and 13d disposed on both surfaces of the plate-like member 13b and a resistor (not shown) formed inside the plate-like member 13b. I have. The plate-like member 13b is made of an insulator, and the pair of electrode portions 13c and 13d are made of a conductor. The resistor is electrically connected to the pair of electrode portions 13c and 13d. As long as the current flowing in the stacking direction of the plurality of cells 10a can be measured, the structure of the current measurement unit 13a is not limited to the above structure, and may be another structure.

  As shown in FIG. 3, the plurality of current measuring units 13 a are arranged in a matrix in the surface direction of the current sensor 13. In other words, the plurality of current measuring units 13 a are arranged in a grid in two orthogonal directions on the plane of the current sensor 13. Thereby, when the current sensor 13 is arranged adjacent to the cell 10a, a plurality of current measuring units 13a are arranged in the plane direction of the cell 10a, so that the current distribution in the plane of the cell 10a is measured by the current sensor 13. can do.

  A through-hole penetrating in the stacking direction of the plurality of cells 10 a is formed in the outer peripheral portion of the current sensor 13. These through holes constitute a manifold part through which air (Air), cooling water (H 2 O), and hydrogen (H 2) flow in the stacking direction of the plurality of cells 10 a when the plurality of cells 10 a are stacked. In the present embodiment, an air supply manifold portion 14a, a cooling water supply manifold portion 15a, and a hydrogen supply manifold portion 16a are formed on the outer peripheral portion on one end side in the longitudinal direction of the current sensor 13. An air discharge manifold portion 14b, a cooling water discharge manifold portion 15b, and a hydrogen discharge manifold portion 16b are formed on the outer peripheral portion on the other end side in the longitudinal direction of the current sensor 13.

  The current detection circuit 51 is a signal processing circuit that performs arithmetic processing on the current flowing in the stacking direction of the cells 10 a from the output signals of the plurality of current measurement units 13 a and outputs the current signal to the control device 50. Specifically, the potential difference between the pair of electrodes 13c and 13d of each current measurement unit 13a detected by a voltage sensor (not shown) and the resistance value of the current path between the pair of electrodes 13c and 13d of each current measurement unit 13a. And processing using. Thereby, the value of the current flowing in the stacking direction of the cells 10a per region corresponding to each current measuring unit 13a of the cell 10a is calculated.

  The control device 50 detects the current distribution in the plane of each cell 10 a based on the current value of each current measurement unit 13 a obtained by the current detection circuit 51. Then, the control device 50 estimates the power generation state of the fuel cell 10 based on the detected current distribution, and controls the air supply amount and supply pressure, the hydrogen supply pressure, the cooling water circulation amount, and the like. This improves the efficiency and reliability of the fuel cell system.

  Here, the DC current distribution in the plane of the cell 10a is detected. However, the AC current distribution in the plane of the cell 10a is detected to detect the impedance distribution in the plane of the cell 10a. Good. In this case, an alternating voltage is applied to the fuel cell 10 using an alternating voltage application means. When an alternating voltage is applied to the fuel cell 10, the current distribution input from the cell monitor 11 and the current detection circuit 51 is measured. And based on the change of the voltage value measured with the cell monitor 11, and the change of the current distribution input from the current detection circuit 51, the alternating current impedance of each cell 10a can be measured by calculation.

  As shown in FIG. 2, the plurality of cells 10 a includes a first cell 10 a 1 having a cathode separator adjacent to the current sensor 13, a second cell 10 a 2 having an anode separator adjacent to the current sensor 13, and the current sensor 13. The third cell 10a3 is not (that is, away from the current sensor 13). Hereinafter, the first cell 10a1 will be described with reference to FIGS. FIG. 4 is a cross-sectional view of the first cell 10a1 corresponding to the cross-sectional position along the line AA in FIG.

  As shown in FIG. 4, the first cell 10a1 includes an electrolyte membrane 110, a cathode side electrode 120 (also referred to as an oxygen electrode or an oxidant electrode), an anode side electrode 130 (also referred to as a hydrogen electrode or a fuel electrode), a cathode A side separator 140 and an anode side separator 150 are provided. Although not shown, the cathode side electrode 120 has a catalyst layer on the electrolyte membrane side and a gas diffusion layer. Although not shown, the anode side electrode 130 includes a catalyst layer on the electrolyte membrane side and a gas diffusion layer. In this embodiment, a membrane electrode gas diffusion layer assembly (MEGA) in which an electrolyte membrane, a catalyst layer, and a gas diffusion layer are integrated is used as the structure of the electrolyte membrane 110 and both electrodes 120 and 130.

  The cathode-side separator 140 and the anode-side separator 150 electrically connect adjacent cells 10a, and a reactive gas (hydrogen or air) flowing through one cell 10a of the adjacent cells 10a flows into the other cell 10a. It is a thing to cut off.

  As shown in FIG. 5, a through-hole penetrating in the stacking direction of the plurality of cells 10 a is formed in the outer peripheral portion of the cathode-side separator 140. These through holes constitute a manifold part through which air (Air), cooling water (H 2 O), and hydrogen (H 2) flow in the stacking direction of the plurality of cells 10 a when the plurality of cells 10 a are stacked. In the present embodiment, an air supply manifold portion 141a, a cooling water supply manifold portion 142a, and a hydrogen supply manifold portion 143a are formed on the outer peripheral portion on one end side in the longitudinal direction of the cathode side separator 140. An air discharge manifold portion 141b, a cooling water discharge manifold portion 142b, and a hydrogen discharge manifold portion 143b are formed on the outer peripheral portion on the other end side in the longitudinal direction of the cathode side separator 140.

  An air flow in which air flows in a direction orthogonal to the stacking direction of the plurality of cells 10a in the electrode facing region 144 facing the cathode side electrode 120 of the cathode side separator 140 and facing the cathode side electrode 120. A channel (oxidant gas channel) 141c is provided. The air flow path 141c has a plurality of linear flow path shapes between the air supply manifold portion 141a and the air discharge manifold portion 141b.

  Further, as shown in FIG. 4, a cooling water flow path 142c through which cooling water flows is provided on the surface of the cathode side separator 140 opposite to the cathode side electrode 120 side.

  Although not shown, each manifold portion is formed on the outer peripheral portion of the anode-side separator 150 similarly to the cathode-side separator 140. As shown in FIG. 4, a hydrogen channel (fuel gas channel) 153 c through which hydrogen flows is provided on the surface of the anode separator 150 that faces the anode electrode 130. Similar to the air flow path 141c, the hydrogen flow path 153c has a plurality of linear flow path shapes between the hydrogen supply manifold portion and the hydrogen discharge manifold portion. Further, a cooling water flow path 152 c is provided on the surface of the anode side separator 150 opposite to the anode side electrode 130 side, similarly to the cooling water flow path 142 c of the cathode side separator 140.

  As shown in FIG. 4, the electrode facing region 144 of the cathode separator 140 of the first cell 10a1 and the plurality of electrode portions 13c of the current sensor 13 are in contact with each other. The electrode facing region 144 of the cathode-side separator 140 has a plurality of conductive portions 145 and a high resistance portion 146 that is higher in resistance than the plurality of conductive portions 145 and partitions each of the plurality of conductive portions 145. Yes. The high resistance portion 146 is formed at a site that structurally connects two adjacent electrode portions 13c.

  In the present embodiment, as shown in FIG. 5, the number of the plurality of conductive portions 145 is the same as the number of the plurality of electrode portions 13 c arranged on the one surface side of the current sensor 13, and the plurality of conductive portions 145 are: Similar to the plurality of electrode portions 13c of the current sensor 13, they are arranged in a matrix. That is, the plurality of conductive portions 145 are arranged side by side in a direction parallel to a plurality of linear air flow paths 141c and in a direction perpendicular to the direction. Each of the plurality of conductive portions 145 is in contact with the electrode portion 13 c facing each of the plurality of conductive portions 145 among the plurality of electrode portions 13 c of the current sensor 13. In other words, any one of the plurality of conductive portions 145 is electrically connected to any one of the plurality of electrode portions 13 c of the current sensor 13. For this reason, when a current flows in the stacking direction of the plurality of cells 10a, a current flowing through one conductive portion 145 flows into one opposing electrode portion 13c.

  As a result, current wraparound when current flows from each of the local regions of the cell 10a1 to the plurality of current measurement units 13a can be suppressed. That is, when a current flows in the stacking direction of the cells 10a, a current flowing out from a partial region of the cell 10a1 flows toward one current measuring unit 13a, and the stacking direction of the cells 10a1 in the separator 140 It is possible to suppress the flow from flowing in a direction orthogonal to the direction toward the adjacent current measuring unit 13a.

  In the present embodiment, as shown in FIG. 4, the electrode facing region 144 of the cathode side separator 140 has a corrugated cross section, and has an uneven shape on both sides of the cathode side separator 140. For this reason, the electrode facing region 144 of the cathode separator 140 includes a first contact portion 144a that contacts the cathode side electrode 120, a second contact portion 144b that contacts the electrode portion 13c of the current sensor 13, and the cathode side electrode 120. It has the connection part 144c which does not contact any of the electrode parts 13c and connects the first contact part 144a and the second contact part 144b. The high resistance portion 146 includes a high resistance portion 146a extending in a direction parallel to the plurality of linear air flow paths 141c and a high resistance portion 146b extending in a direction perpendicular to the plurality of linear air flow paths 141c. (See FIG. 5). A high resistance portion 146a extending in a direction parallel to the plurality of linear air flow paths 141c is formed in the connecting portion 144c. Moreover, the high resistance part 146 has the frame-shaped high resistance part 146c surrounding all the some linear air flow paths 141c, as shown in FIG. In addition, although the high resistance parts 146a, 146b, and 146c of each shape are connected in this embodiment, they may not be connected. In short, the high resistance portion 146 may be one or may be divided into a plurality.

  The cathode-side separator 140 is manufactured by press-molding a base material made of a single plate-like metal material. Concave and convex shapes are formed on both surfaces of the cathode-side separator 140 by press molding. The air flow path 141c is configured by the concavo-convex shape formed on one side of the cathode-side separator 140. The cooling water flow path 142c is configured by an uneven shape formed on the other side of the cathode-side separator 140.

  The high resistance portion 146 is formed by oxidizing a part of the press-molded base material, and is composed of an oxide of the base material, that is, an oxide of a metal element contained in the base material. ing. For this reason, the high resistance part 146 has no joint surface between the conductive part 145 and has an integrated structure continuous with the conductive part 145. As the oxidation treatment for forming the high resistance portion 146, a thermal oxidation treatment in which heating is performed in an oxygen atmosphere can be employed.

In this embodiment, the separator 140 is manufactured by press-molding a metal plate made of Ti. Then, the region where the high resistance portion 146 is to be formed in the press-molded metal plate is locally heated using a semiconductor laser in an oxygen atmosphere. At this time, the heating conditions are set so that the entire thickness direction of the metal plate is oxidized. Thereby, the high resistance part 146 made of TiO ₂ is formed in the separator 140.

  In addition, as an oxidation process for forming the high resistance part 146, you may employ | adopt the anodic oxidation process which electrolyzes in electrolyte solution. However, when anodizing is performed on the metal plate, an oxide film is formed on the surface of the metal plate. For this reason, when the anodizing treatment is employed, the surface of the first contact portion 144a that contacts the cathode-side electrode 120 or the electrode portion of the current sensor 13 so that the current flow between the adjacent conductive portions 145 can be suppressed. The high resistance portion 146 is formed on the surface of the second contact portion 144b that comes into contact with 13c. Even if it does in this way, the wraparound of the electric current when an electric current flows into each of the some electric current measurement part 13a from each local area | region of the cell 10a1 can be suppressed. Also in this case, as shown in FIG. 5, the high resistance portion 146 is formed at a position separating each of the plurality of conductive portions 145 on the planar layout of the cathode-side separator 140.

  The anode-side separator 150 is also manufactured by press-molding a base material made of a single plate-like metal material, like the cathode-side separator 140, except for the formation of the high resistance portion 146.

  Next, the second cell 10a2 will be described with reference to FIG. FIG. 6 is a cross-sectional view of the second cell 10a2, and corresponds to FIG.

  The second cell 10a2 is different from the first cell 10a1 in that the high resistance portion 156 is formed on the anode side separator 150 adjacent to the current sensor 13 and the high resistance portion 146 is not formed on the cathode side separator 140. In other respects, the configuration is the same as that of the first cell 10a1.

  That is, the anode-side separator 150 of the second cell 10a2 has a plurality of conductive portions 155 and a high resistance portion 156 in the electrode facing region 154 facing the anode-side electrode 130. The electrode facing region 154, the conductive portion 155, and the high resistance portion 156 correspond to the electrode facing region 144, the conductive portion 145, and the high resistance portion 146 in the cathode separator 140 of the first cell 10a1, respectively.

  The second cell 10a2 is located on the downstream side of the current sensor 13 in the current flow in the stacking direction of the plurality of cells 10a. For this reason, in the 2nd cell 10a2, the wraparound of the electric current to the surface direction of the cell in the electric current which flows into the 2nd cell 10a2 from the current sensor 13 can be suppressed.

  Of the plurality of cells 10a, the third cell 10a3 is basically the same structure as the first cell 10a1. However, the cathode side separator 140 of the third cell 10a3 has the same shape as the cathode side separator 140 of the first cell 10a1, but is different in that the high resistance portion 146 is not provided.

  As described above, in the present embodiment, in the first cell 10a1, the electrode facing region 144 of the cathode-side separator 140 has a plurality of conductive portions 145 and a high resistance portion 146 that separates each of the plurality of conductive portions 145. doing. According to this, since the electrode facing region 144 of the cathode separator 140 is divided into the plurality of conductive portions 145, the current distribution in the plane of the cell 10a can be measured. Note that “separate each of the plurality of conductive portions 145” means that the plurality of conductive portions 145 are separated to an extent that current flow between at least adjacent conductive portions 145 can be suppressed, It does not mean that each of the plurality of conductive portions 145 is completely insulated and separated.

  Further, in the present embodiment, the cathode separator 140 of the first cell 10a1 is formed using a base material made of a single plate-like metal material, and the high resistance portion 146 is oxidized against a part of the base material. Formed by processing. For this reason, the high resistance part 146 is comprised with the oxide of the metal element contained in a base material. According to this, a part of one member constituting the cathode side separator 140 is oxidized (chemically changed) to form the high resistance portion 146. Therefore, the two members are joined and integrated to form the separator. Compared with the case where it does, the crack generation by a thermal stress can be suppressed.

  In the present embodiment, also in the anode-side separator 150 of the second cell 10a2, the electrode facing region 154 is divided into a plurality of conductive portions 155 by the high resistance portion 156. The high resistance portion 156 of the second cell 10a2 is also formed by oxidizing part of the base material constituting the anode separator 150. Therefore, the same can be said for the anode-side separator 150 of the second cell 10a2 as for the cathode-side separator 140 of the first cell 10a1.

  Therefore, according to the present embodiment, the durability of the cathode side separator 140 of the first cell 10a1 and the anode side separator 150 of the second cell 10a2 can be improved as compared with the fuel cell of Patent Document 1 described above. .

  In the present embodiment, the cathode side having the high resistance portion 146 of the first cell 10a1 is formed by press-molding a base material made of a single plate-like metal material and oxidizing part of the base material. The separator 140 is manufactured. The same applies to the anode-side separator 150 of the second cell 10a2. For this reason, according to this embodiment, the complexity of the process of integrating the two members in the case of forming the separator having the high resistance portion by integrating the two members of the conductive material and the non-conductive material. Can be eliminated.

  In the present embodiment, the cathode separator 140 of the first cell 10a1 is configured using a separator having the same shape as the cathode separator of the third cell 10a3. The same applies to the anode-side separator 150 of the second cell 10a2. As a result, the production of the fuel cell 10 is made in comparison with the case where the cathode-side separator 140 of the first cell 10a1 and the anode-side separator 150 of the second cell 10a2 are configured with shapes different from the separator of the third cell 10a3. Can increase the sex.

(Second Embodiment)
In the first embodiment, the current sensor 13 with the separator not attached to the surface is laminated with the plurality of cells 10a. However, in this embodiment, as shown in FIG. The pasted current sensor 13 is stacked with a plurality of cells 10a. The separator 160 has the same shape as the cathode-side separator 140 of the first embodiment, and the separator 170 has the same shape as the anode-side separator 150 of the first embodiment.

  In the present embodiment, two separators of the separator 140 and the separator 170 are overlapped to constitute the cathode side separator 180 of the first cell 10a1.

  Also in the present embodiment, in the cathode side separator 180 of the first cell 10a1, the electrode facing region 144 is partitioned into a plurality of conductive portions 145 by the high resistance portion 146, similarly to the cathode side separator 140 of the first embodiment. ing. For this reason, there exists an effect similar to 1st Embodiment.

  Also in the present embodiment, as in the first embodiment, the cathode separator 180 of the first cell 10a1 is configured using a separator having the same shape as the separator not adjacent to the current sensor 13. Thereby, the productivity of the fuel cell 10 can be increased. In the present embodiment, the cathode separator of the first cell 10a1 has been described. The same applies to the anode separator of the second cell 10a2.

  In the present embodiment, the electrode portions 13c and 13d of the current sensor 13 are not joined to the opposing separators 170 and 160, but are simply in contact with each other. Portions of the current sensor 13 other than the electrode portions 13c and 13d are joined to the opposing separators 170 and 160 via an adhesive. In particular, portions of the current sensor 13 around the manifold portions 14a, 14b, 15a, 15b, 16a, and 16b are joined to the opposing separators 170 and 160 via an adhesive. This prevents gas leakage.

(Third embodiment)
As shown in FIG. 8, in the present embodiment, as in the second embodiment, the current sensor 13 having separators 160 and 170 attached in advance to the surface is stacked with a plurality of cells 10a. For this reason, the two separators 140 and 170 are overlapped to form a cathode-side separator 180 adjacent to the current sensor 13. The separator 170 constitutes a first separator, and the separator 140 constitutes a second separator located on the side farther from the current sensor than the first separator.

  Furthermore, in this embodiment, as described below, a conductive material is arranged in a space that is not used as a gas flow path in the separator 170.

  The separator 170 has an uneven shape, similar to the anode-side separator 150. Separator 170 forms cooling water flow path 142 c between separator 140. The separator 170 forms a plurality of spaces 171 between the current sensor 13. Therefore, the separator 170 separates the cooling water flowing through the cooling water flow path 142 c and the plurality of spaces 171 between the separator 170 and the current sensor 13. The plurality of spaces 171 includes a space 172 that faces only one electrode portion 13c and a space 173 that faces two electrode portions 13c. The space 172 is a space surrounded by the separator 170 and one electrode portion 13c. This space 172 is a space having the same shape as the hydrogen flow path 153c, but is not used as a hydrogen flow path.

  Therefore, in the present embodiment, a solidified material 174 obtained by solidifying a conductive paste is disposed in the space 172 as a conductive material. The conductive paste is obtained by dissolving or dispersing conductive powder in a solvent. Therefore, the solidified product 174 of the conductive paste is an aggregate of conductive powder. Examples of the conductive powder include metal powders such as copper and silver. The shape of the conductive powder may be either spherical or rod-like. The size of the conductive powder may be any size. Examples of the solvent include organic solvents, synthetic resins, and water. In manufacturing the current sensor 13 in which the separators 160 and 170 are integrated, after the conductive paste is poured into the space 172, the conductive paste is solidified. Thereby, the solidified product 174 of the conductive paste is formed.

  According to the present embodiment, since the conductive material is disposed in the space 172, the current path connected to the current measuring unit 13a in the cathode side separator 180 can be expanded. Thereby, the resistance of the current path connected to the current measurement unit 13a can be reduced, and the accuracy of current measurement by the current sensor 13 can be improved.

  In this embodiment, the conductive paste is solidified. However, the conductive paste may not be solidified as long as it has conductivity. Further, as the conductive material, a material other than the conductive paste may be used. The conductive material should just be the structure which electrically connected the part which opposes on both sides of the space 172 with respect to one electrode part 13c among separators, and one electrode part 13c.

  Further, when the conductive material is densely disposed in the space 172, the heat capacity inside the space 172 increases. On the other hand, when the conductive material is disposed in the space 172 in a sparse state, the electrical resistance inside the space 172 increases. For this reason, it is preferable to select a conductive material so that the heat capacity and electric resistance inside the space 172 have desired sizes. For example, when it is desired to keep the heat capacity small, it is preferable to use a structure having a void called a conductive foam or a conductive cushion material as the conductive material.

  In the present embodiment, the conductive material is disposed in the space 172 surrounded by the separator 170 and the one electrode portion 13c in the separator 170 among the separators 160 and 170 attached to the current sensor 13. A conductive material may be disposed in a space surrounded by 160 and one electrode portion 13d.

(Fourth embodiment)
As shown in FIG. 9, in the present embodiment, in the current sensor 13 in which the separators 160 and 170 are attached to the surface in advance, the separator 170 and the plurality of electrode portions 13 c are joined via the low melting point metal material 191. Yes. In other words, the cathode-side separator 180 adjacent to the current sensor 13 and the plurality of electrode portions 13 c are joined via the low melting point metal material 191. Further, in the current sensor 13 in which the separators 160 and 170 are attached to the surface in advance, the separator 160 and the plurality of electrode portions 13 d are joined via the low melting point metal material 192.

  The low melting point metal materials 191 and 192 are metal materials having a melting point lower than that of the base material constituting the separators 160 and 170 and the metal material constituting the electrode portions 13c and 13d. For example, titanium is used as the base material, copper is used as the metal material constituting the electrode portions 13c and 13d, and solder is used as the low melting point metal materials 191 and 192.

  Next, a method for joining the separators 160 and 170 and the plurality of electrode portions 13c and 13d will be described.

  As shown in FIG. 10, paste-like or melted low-melting point metal materials 191 and 192 are applied to the surfaces of the plurality of electrode portions 13c and 13d. Thereby, the low melting point metal materials 191 and 192 are installed on the surfaces of the plurality of electrode portions 13c and 13d.

  Subsequently, as shown in FIG. 11, the separators 160 and 170 are assembled to the current sensor 13 with the low melting point metal materials 191 and 192 installed on the surfaces of the plurality of electrode portions 13 c and 13 d. At this time, although not shown, at least the portions around the manifold portions 14a, 14b, 15a, 15b, 16a, and 16b of the current sensor 13 are bonded to the opposing separators 170 and 160 with an adhesive.

  Then, the low melting point metal materials 191 and 192 are heated and melted by flowing hot air through the space between the current sensor 13 and the separators 160 and 170. Thereafter, the low melting point metal materials 191 and 192 are cooled and solidified. Thereby, separators 160 and 170 and a plurality of electrode parts 13c and 13d are joined via low melting metal material 191 and 192. Thereafter, as shown in FIGS. 2 and 9, the plurality of cells 10 and the current sensor 13 are stacked.

  In the present embodiment, the low melting point metal materials 191 and 192 installed on the surfaces of the electrode portions 13c and 13d are melted, so that the separators 160 and 170 and the electrode portions 13c and 13d form the low melting point metal materials 191 and 192. It is joined metallically. According to this, compared with the case where the separators 160 and 170 and the electrode parts 13c and 13d are simply contacting, the contact resistance with the separators 160 and 170 in one electrode part 13c and 13d can be lowered. Further, variation in contact resistance with the separators 160 and 170 in each of the plurality of electrode portions 13c and 13d can be reduced.

  In the present embodiment, the low melting point metal materials 191 and 192 are heated by flowing hot air through the space between the current sensor 13 and the separators 160 and 170, but other heating methods may be employed. For example, hot air may be applied to the surface of the separators 160 and 170 opposite to the current sensor 13 side. In addition, a plate-shaped heating plate may be applied to the surface of the separators 160 and 170 on the side opposite to the current sensor 13 side, and heat pressing may be performed. Further, a heating plate having a concavo-convex shape along the surface opposite to the current sensor 13 side of the separators 160 and 170 is applied to the surface of the separators 160 and 170 opposite to the current sensor 13 side, and is heated and pressed. Also good.

  In the present embodiment, both the separator 170 and the separator 160 are joined to the plurality of electrode portions via the low melting point metal material, but only the separator 170 of the separator 170 and the separator 160 is made of the low melting point metal material. It may be joined to a plurality of electrode parts via.

  Further, the contact structure between the separators 160 and 170 of the present embodiment and the plurality of electrode portions 13c and 13d may be applied to the contact structure between the separator 140 and the plurality of electrode portions 13c of the first embodiment. That is, you may join the separator 140 of 1st Embodiment, and the some electrode part 13c via a low melting metal material.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be appropriately modified within the scope described in the claims as follows.

  (1) In the first embodiment, the air flow channel 141c of the cathode separator 140 has a plurality of linear flow channel shapes between the air supply manifold portion 141a and the air discharge manifold portion 141b. As shown in FIG. 12, it may have a serpentine-like channel shape. The same applies to the hydrogen flow path 153c of the anode-side separator 150.

  (2) The cross-sectional shape of the cathode-side separators 140 and 180 of the first cell 10a1 is not limited to the shape shown in FIGS. 4 and 7, and may be other shapes. The same applies to the cross-sectional shape of the anode separator 150 of the second cell 10a2.

  (3) In the first embodiment, as in the first cell 10a1 and the second cell 10a2, the high resistance portions 146 and 156 are formed on one of the cathode side separator 140 and the anode side separator 150 in one cell 10a. However, when the current sensor 13 is disposed on both sides of one cell 10a, the high resistance portions 146 and 156 may be formed on both the cathode side separator 140 and the anode side separator 150 in one cell 10a. .

  (4) Although the fuel cell 10 of the first embodiment includes a plurality of current sensors 13, the number of the current sensors 13 may be one. The fuel cell of the present invention only needs to include at least one current sensor 13.

  (5) The above-described embodiments are not irrelevant to each other, and can be appropriately combined unless the combination is clearly impossible. In each of the above-described embodiments, it is needless to say that elements constituting the embodiment are not necessarily essential unless explicitly stated as essential and clearly considered essential in principle. Yes.

DESCRIPTION OF SYMBOLS 10 Fuel cell 10a Cell 10a1 1st cell 10a2 2nd cell 110 Electrolyte membrane 120 Cathode side electrode 130 Anode side electrode 140 Cathode side separator 144 Electrode facing area 145 Conductive part 146 High resistance part 150 Anode side separator 180 Cathode side separator

Claims (5)

An electrolyte (110);
A cathode side electrode (120) and an anode side electrode (130) provided on both sides of the electrolyte;
A cathode side separator (140, 180) provided on the opposite side of the cathode side electrode from the electrolyte side and having a flow path (141c) for an oxidant gas supplied to the cathode side electrode;
An anode separator (150) provided on the opposite side of the anode side electrode from the electrolyte side and having a fuel gas flow path (153c) supplied to the anode side electrode;
At least one of the anode-side separator and the cathode-side separator has a plurality of conductive portions (145) and a plurality of the plurality of conductive portions in the electrode facing regions (144, 154) facing the anode-side electrode or the cathode-side electrode. A high resistance portion (146) that is higher in resistance than the conductive portion and separates each of the plurality of conductive portions;
The at least one separator is composed of a base material made of a metal material,
The plurality of conductive portions are composed of the base material,
The fuel cell according to claim 1, wherein the high resistance portion is made of an oxide of the base material. The electrolyte (110), the cathode side electrode (120) and the anode side electrode (130) provided on both sides of the electrolyte, and the cathode side electrode provided on the opposite side of the electrolyte side, A fuel gas supplied to the anode side electrode, provided on the opposite side of the anode side electrode from the electrolyte side of the cathode side separator (140, 180) having a flow path (141c) for the supplied oxidant gas A plurality of cells (10a) stacked together and having an anode-side separator (150) having a flow path (153c) of
Including at least one current sensor (13) stacked with the plurality of cells and electrically connected in series with the plurality of cells;
One current sensor has a plurality of current measuring units (13a) in contact with the adjacent cells,
Among the anode side separator and the cathode side separator of each of the plurality of cells, a separator adjacent to the current sensor is a plurality in the electrode facing region (144, 154) facing the anode side electrode or the cathode side electrode. A conductive portion (145), and a high resistance portion (146) that is higher in resistance than the plurality of conductive portions and separates each of the plurality of conductive portions,
Each of the plurality of conductive parts is electrically connected to any one of the plurality of current measurement parts.
The separator adjacent to the current sensor is composed of a base material made of a metal material,
The plurality of conductive portions are composed of the base material,
The fuel cell according to claim 1, wherein the high resistance portion is made of an oxide of the base material.   The separator adjacent to the current sensor is configured using a separator having the same shape as the separator not adjacent to the current sensor among the anode side separator and the cathode side separator of each of the plurality of cells. The fuel cell according to claim 2. In the separator (180) adjacent to the current sensor, the first separator (170) and the second separator (140) located on the side farther from the current sensor than the first separator are overlapped,
A space (172) surrounded by the first separator and the one current measuring unit is formed,
The fuel cell according to claim 2, wherein a conductive material (174) is disposed in the space. The current measuring unit includes an electrode unit (13c) made of a metal material,
The separator (180) adjacent to the current sensor is joined to the electrode part via a metal material constituting the electrode part and a low melting point metal material (191) having a melting point lower than that of the base material. The fuel cell according to any one of claims 2 to 4, wherein:

Images