JP2010257831A - Method of manufacturing fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a fuel cell in which distribution of ionomer in an electrode is appropriate. <P>SOLUTION: A method of manufacturing the fuel cell includes a step of forming a catalyst ink containing the ionomer under a prescribed forming condition, a step of forming a first electrode by using the catalyst ink, a step of forming a membrane-electrode assembly in which the first electrode is arranged on one face of an electrolyte membrane and a second electrode is arranged on the other face of the electrolyte membrane, a step of forming the fuel cell by using the membrane-electrode assembly, a step of measuring an alternating current impedance of the membrane-electrode assembly equipped in the fuel cell while changing a frequency, a step of estimating distribution of the ionomer in the thickness direction of the first electrode in the first electrode based on the alternating current impedance at every frequency, and a feedback step of adjusting the forming condition (solid content ratio of catalyst ink) in the catalyst ink-forming step so that the distribution of the ionomer becomes the targeted one. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for manufacturing a fuel cell.

  Conventionally, a fuel cell is known. The fuel cell includes a membrane electrode assembly in which electrodes are disposed on both surfaces of an electrolyte membrane. By supplying an oxidizing gas (for example, air) containing oxygen to one electrode and supplying a fuel gas (for example, hydrogen) to the other electrode, the hydrogen and oxygen are reacted electrochemically and directly. Electrical energy can be extracted.

  An AC impedance method has been proposed as a method for inspecting and evaluating fuel cells (see Patent Document 1 below).

JP 2005-71882 A

  However, the conventional technology only determines the quality of the fuel cell, and a fuel cell with an appropriate ionomer distribution in the electrodes provided in the fuel cell can be manufactured even using this quality determination technology. There was a problem that could not.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for manufacturing a fuel cell in which an ionomer distribution in an electrode is appropriate.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples or forms.

[Application Example 1] A fuel cell manufacturing method, in which a catalyst ink containing an ionomer is created under predetermined creation conditions, and a first electrode is created using the catalyst ink A membrane electrode assembly creating step for creating a membrane electrode assembly in which the first electrode is disposed on one surface of the electrolyte membrane and the second electrode is disposed on the other surface of the electrolyte membrane; A fuel cell production step for producing a fuel cell in which a gas diffusion layer and a separator are laminated on a membrane electrode assembly, and a measurement step for measuring the AC impedance of the membrane electrode assembly provided in the fuel cell while changing the frequency, An estimation step of estimating a distribution of the ionomer in the thickness direction of the first electrode in the first electrode based on the AC impedance for each frequency measured in the measurement step; It said estimation step as the distribution of the ionomer obtained is a target distribution by manufacturing method of a fuel cell and a feedback step of adjusting the production conditions in the catalyst ink making process.

  According to the fuel cell manufacturing method described in Application Example 1, the ionomer distribution in the thickness direction of the first electrode in the first electrode provided in the fuel cell is estimated, and the estimation result is generated in the catalyst ink preparation process. Since it is fed back to the conditions, the ionomer distribution in the first electrode is controlled to the target distribution. Therefore, according to the fuel cell evaluation method, a fuel cell in which the ionomer distribution in the electrode is appropriate can be manufactured.

 [Application Example 2] In the fuel cell manufacturing method according to Application Example 1, the predetermined preparation condition is a condition related to a solid content ratio of the catalyst ink, and the feedback step includes a ratio of the solid content of the catalyst ink. The manufacturing method of a fuel cell including the structure which adjusts.

  There is a correlation between the solid content ratio of the catalyst ink and the ionomer distribution in the thickness direction of the first electrode in the first electrode made of the catalyst ink. Therefore, the ionomer distribution in the first electrode can be easily controlled appropriately by feeding back the estimation result of the ionomer distribution and adjusting the ratio of the solid content of the catalyst ink.

 Application Example 3 In the fuel cell manufacturing method according to Application Example 1, the predetermined creation condition is a condition for a catalyst ink creation procedure, and the feedback step changes the catalyst ink creation procedure. A method for producing a fuel cell, comprising:

  There is a correlation between the preparation procedure of the catalyst ink and the ionomer distribution in the thickness direction of the first electrode in the first electrode prepared with the catalyst ink. Therefore, it is possible to easily control the ionomer distribution in the first electrode by feeding back the estimation result of the ionomer distribution and adjusting the preparation procedure of the catalyst ink.

 [Application Example 4] In the method of manufacturing a fuel cell according to Application Example 1, the predetermined preparation condition is a condition regarding an SP value of a solvent used for preparation of the catalyst ink. A method for manufacturing a fuel cell, including a configuration for adjusting an SP value.

  There is a correlation between the SP value of the solvent used in the preparation of the catalyst ink and the ionomer distribution in the thickness direction of the first electrode in the first electrode prepared with the catalyst ink. Therefore, it is possible to easily control the ionomer distribution in the first electrode by feeding back the estimation result of the ionomer distribution and adjusting the SP value of the solvent.

[Application Example 5] In the method of manufacturing a fuel cell according to any one of Application Examples 1 to 4, in the estimation step, an inert gas is introduced into the first electrode of the membrane electrode assembly provided in the fuel cell. A method for manufacturing a fuel cell, which is configured to perform the measurement.

  According to the fuel cell evaluation method described in Application Example 5, the ionomer distribution in the thickness direction can be accurately estimated.

[Application Example 6] In the method of manufacturing a fuel cell according to any one of Application Examples 1 to 5, the estimation step includes plot points each including an AC impedance at each frequency measured in the measurement step in a complex plane. A method for producing a fuel cell, comprising: obtaining a complex impedance plot curve from: and estimating a distribution of the ionomer in the thickness direction of the first electrode on the first electrode based on the complex impedance plot curve. .

  According to the fuel cell manufacturing method described in Application Example 6, it is possible to accurately estimate the ionomer distribution in the thickness direction.

  The present invention can also be realized in other aspects of the method invention, such as a method for manufacturing a membrane electrode assembly or a method for manufacturing a fuel cell electrode, in addition to the above-described method for manufacturing a fuel cell. Further, the present invention is not limited to the aspect of the method invention, and can be realized as an aspect of the apparatus invention. Further, aspects as a computer program for constructing these methods and apparatuses, aspects as a recording medium recording such a computer program, data signals embodied in a carrier wave including the computer program, etc. It can also be realized in various ways.

It is a cross-sectional schematic diagram showing schematic structure of the fuel cell CL manufactured by 1st Example of this invention. It is a flowchart which shows the manufacturing method of the fuel cell CL in 1st Example. It is explanatory drawing which shows schematic structure of the fuel cell evaluation apparatus 10 used with the said manufacturing method with the fuel cell CL. 3 is a flowchart showing a fuel cell evaluation process executed by the fuel cell evaluation device 10. It is explanatory drawing which shows the cyclic voltammogram of a fuel cell. 5 is a graph showing a complex impedance plot curve V. It is the figure which expanded the turning point P vicinity in the complex impedance plot curve V. FIG. It is a flowchart which shows the new catalyst ink preparation process performed by step S220 of the said manufacturing method. It is a figure about Table TBL1 showing the relationship between the solid content ratio of the catalyst ink and the tangent angle θ in the complex impedance plot curve V. It is a figure about Table TBL2 showing the relationship between the preparation procedure of the catalyst ink and the tangent angle θ in the complex impedance plot curve V. It is a flowchart which shows the new catalyst ink preparation process in 2nd Example. It is a figure about Table TBL3 showing the relationship between the SP value of the solvent and the tangent angle θ in the complex impedance plot curve V. It is a flowchart which shows the new catalyst ink preparation process in 2nd Example.

  Hereinafter, embodiments of the present invention will be described based on examples.

A. First embodiment:
Next, a method for manufacturing a fuel cell as a first embodiment of the present invention will be described. A fuel cell is generally configured as a fuel cell stack in which a plurality of fuel cells are stacked. Here, the present invention is applied as a method for manufacturing one fuel cell. The fuel cell is of a solid polymer type and generates power using an oxidizing gas (for example, air) and a fuel gas (for example, hydrogen).

A-1. Fuel cell configuration:
FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a fuel cell CL manufactured by this fuel cell manufacturing method. The fuel cell CL includes a membrane electrode assembly (hereinafter referred to as MEA (Membrane Electrode Assembly)) 50, gas diffusion layers 60 and 70, separators 80 and 90, and a seal member 110.

  The MEA 50 includes an electrolyte membrane 51, a cathode 52 disposed on one surface of the electrolyte membrane 51, and an anode 53 disposed on the other surface of the electrolyte membrane 51. The cathode 52 corresponds to the “first electrode” in the application example, and the anode 53 corresponds to the “second electrode” in the application example.

  The electrolyte membrane 51 is a proton conductive ion exchange membrane formed of a solid polymer material, for example, a fluorine-based resin, and exhibits good proton conductivity in a wet state. The electrolyte membrane 51 is not limited to the fluorine resin, and may be composed of, for example, a hydrocarbon resin.

  The cathode 52 and the anode 53 contain a catalyst metal-supported carrier and an ionomer. The “catalyst metal-supported carrier” is a catalyst metal (platinum, palladium, etc.) supported on a carrier (carbon black, ketjen black, etc.). The “ionomer” is an electrolyte having proton conductivity (for example, a fluorine resin). The ionomer is not limited to a fluorine resin, and may be composed of, for example, a hydrocarbon resin.

  The gas diffusion layer 60 is disposed on one surface of the MEA 50, and the gas diffusion layer 70 is disposed on the other surface of the MEA 50. Each gas diffusion layer 60 and 70 is a carbon porous member having conductivity, and is formed of, for example, carbon cloth or carbon paper.

  A direction in which the members are stacked in the fuel cell CL is also referred to as a stacking direction. The stacking direction is the same direction as the thickness direction of each member of the fuel cell CL.

  The separators 80 and 90 can be formed of a gas-impermeable conductive member, for example, dense carbon that has been made to be gas-impermeable by compressing carbon, or a press-molded metal plate. The separator 80 has an uneven shape in which convex portions 82a and concave portions 82b are alternately formed on one side. In the separator 80, the convex portion 82 a presses the gas diffusion layer 60 (the cathode 52 or the electrolyte membrane 51), and the concave portion 82 b is between the gas diffusion layer 60 and the gas diffusion layer 60 (cathode 52). An in-cell flow path 82 is formed to supply and discharge oxidizing gas. The separator 90 has an uneven shape in which convex portions 92a and concave portions 92b are alternately formed on one surface. In the separator 90, the convex portion 92 a presses the gas diffusion layer 70 (the anode 53 or the electrolyte membrane 51), and the concave portion 92 b is between the gas diffusion layer 70 and the fuel gas with respect to the gas diffusion layer 70 (anode 53). In-cell flow path 92 is formed to supply and discharge the gas.

  Each separator 80, 90 includes holes 103 to 106 at positions corresponding to each other near the outer periphery thereof. When the separators 80 and 90 are stacked together with the MEA 50 and the gas diffusion layers 60 and 15 to assemble the fuel cell, the holes provided at the corresponding positions of the stacked separators 80 and 90 overlap each other. A flow path that penetrates the inside of the fuel cell is formed in the direction. Specifically, the hole 103 forms an oxidizing gas supply manifold, the hole 104 forms an oxidizing gas discharge manifold, the hole 105 forms a fuel gas supply manifold, and the hole 106 is a fuel. A gas exhaust manifold is formed. The oxidizing gas supply manifold is a channel for introducing oxidizing gas into the in-cell channel 82, and the oxidizing gas discharge manifold is a channel for discharging oxidizing gas from the in-cell channel 82. The fuel gas supply manifold is a flow path for introducing fuel gas into the in-cell flow path 92, and the fuel gas discharge manifold is a flow path for discharging fuel gas from the in-cell flow path 92.

  In the fuel cell CL, the seal member 110 is disposed around the in-cell flow path 82, the in-cell flow path 92, and the respective manifolds, and the in-cell flow path 82, the in-cell flow path 92, and the respective manifolds Ensure gas seal.

A-2. Manufacturing method of fuel cell CL:
FIG. 2 is a flowchart showing a method for manufacturing the fuel cell CL in the present embodiment. The manufacturing method of the fuel cell CL is performed by a predetermined operator. Moreover, the atmospheric temperature at the time of performing this manufacturing method is 23 degreeC.

  As shown in the figure, the worker firstly has an electrolyte (for example, a fluorine resin), a solvent (for example, water, alcohol, etc.), and a catalyst metal support (for example, platinum supported on Ketjen Black). And a Teflon (registered trademark) base material are prepared (step S110). Next, the operator mixes the electrolyte, the solvent, and the catalyst metal-supported carrier prepared in Step S110 to create a catalyst ink (Step S120).

  Subsequently, the operator applies the catalyst ink created in step S120 on the base material prepared in step S110 by a decal method to form a layered ink (step S130). Subsequently, the operator creates hot cathode 52 by flowing hot air over the layered ink using a hot air generator (not shown) to create the cathode 52 (step S140). As a result, a cathode 52 containing an ionomer that is an electrolyte and a catalytic metal-supported carrier is produced.

  Thereafter, the operator prepares the anode 53 and the electrolyte membrane 51 prepared in advance (step S150), and creates the MEA 50 by sandwiching the electrolyte membrane 51 between the cathode 52 and the anode 53 created in step S140. (MEA: Step S160). In addition, since the production method of the anode 53 is not directly related to the present invention, it is omitted here, but is produced by a known method. The MEA is performed by hot pressing in a state where the cathode 52 and the anode 53 are disposed on both surfaces of the electrolyte membrane 51. Further, the positional relationship of the cathode 52 with respect to the electrolyte membrane 51 and the positional relationship of the anode 53 with respect to the electrolyte membrane 51 at the time of this hot pressing are the same every time this step S160 is executed. Here, with respect to the electrolyte membrane, The cathode is positioned on the lower side, and the anode is positioned on the upper side with respect to the electrolyte membrane.

  Subsequently, the worker creates fuel cell CL using the manufactured MEA 50 (step S170). Specifically, the gas diffusion layers 60 and 70, the separators 80 and 90, and the seal member 110 are prepared, the seal member 110 is disposed around the MEA 50 created in step S160, and the separators 80 and 90 sandwich them. Thus, the fuel cell CL is created.

  Thereafter, the operator introduces nitrogen (or argon or the like) as an inert gas into the cathode 52 of the fuel cell CL created in step S170, and introduces hydrogen as the active gas into the anode 53 (step S180). . As the hydrogen and nitrogen introduced into the fuel cell CL, a low-humidity gas having a relative humidity in the range of 0.1 to 60% is used. In this case, the relative humidity of hydrogen and nitrogen is particularly preferably in the range of 10 to 20%. Further, the temperature of hydrogen and nitrogen introduced into the fuel cell CL is about 23 ° C. Next, the worker evaluates the fuel cell CL (step S190).

  The evaluation of the fuel cell CL in step S190 is performed using the fuel cell evaluation device 10. FIG. 3 is an explanatory diagram showing a schematic configuration of the fuel cell evaluation device 10 together with the fuel cell CL. As shown in the figure, a fuel cell evaluation device (hereinafter also simply referred to as “evaluation device”) 10 is connected to a fuel cell CL by two sets of wires 20 and 30.

  The evaluation device 10 causes an alternating current to flow through the fuel cell CL via the first wiring 20, measures the AC impedance of the fuel cell CL via the second wiring 30, and determines the fuel cell from the measurement result. The internal state of the cell CL is evaluated (estimated).

  The evaluation device 10 includes a CPU 12, a ROM 14, a RAM 16, an input / output control unit 18, a display unit 19, and the like. The CPU 12 evaluates the internal state of the fuel cell CL described above by executing a process according to a program stored in advance in the ROM 14 (a program describing a fuel cell evaluation process described later). The evaluation result is displayed on the display unit 19 via the input / output control unit 18. In addition, it is good also as a structure which replaces with the display by the display part 19 and alert | reports an evaluation result by another methods, such as an audio | voice.

  FIG. 4 is a flowchart showing a fuel cell evaluation process executed by the evaluation apparatus 10. As shown in the figure, when the processing is started, the CPU 12 of the evaluation apparatus 10 first causes an alternating current to flow through the fuel cell CL at a predetermined interval while changing the frequency at a predetermined interval, and the AC impedance of the fuel cell CL at each frequency. Is detected (measured) (step S310).

  FIG. 5 is an explanatory diagram showing a cyclic voltammogram of the fuel cell. The vertical axis represents the current value [A], and the horizontal axis represents the voltage [V]. The cyclic voltammogram is shown as a current-voltage curve. A region indicated by a one-dot chain line in the figure is an electric double layer region (about 0.3 to 0.5 V). In the process of step S110, a voltage in the electric double layer region (about 0.3 to 0.5 V) shown in FIG. 5 is applied, and an alternating current is supplied with a current value in the electric double layer region.

  Returning to FIG. 3, after executing step S310, the CPU 12 calculates a complex impedance plot curve V for the fuel cell CL based on the AC impedance detected in step S310 (step S320). The complex impedance plot curve is sometimes simply referred to as “complex impedance plot”, and is also referred to as “Cole-Cole plot”. The complex impedance plot curve V is as follows.

  FIG. 6 is a graph showing a complex impedance plot curve V. In FIG. 6, the vertical axis represents the imaginary part value Z2 of the AC impedance, and is hereinafter also referred to as “imaginary part axis”, and the horizontal axis represents the real part value Z1 of the AC impedance. Also called “partial axis”. The complex impedance plot curve V inserts (plots) the AC impedance at each frequency detected in step S310 on a plane formed by the imaginary part axis and the real part axis (hereinafter also referred to as “complex plane”). , A curve (approximate curve) created based on the inserted points (plot points).

  In the drawing, the complex impedance plot curve V is shown by a solid line. Squares in the figure are plot points. Each point in the complex impedance plot curve V has a higher frequency toward the lower left side. Note that the scales of the imaginary part axis and the real part axis are drawn in the same size. That is, in FIG. 6, when the value of the complex impedance plot curve V changes in the real part axis and the imaginary part axis by the same amount, the position on the axis changes by the same amount. In FIG. 6, the turning point P is shown in the complex impedance plot curve V.

The turning point P shown in FIG. 6 is a boundary point where the property of the function changes in the complex impedance plot curve V, that is, in the complex impedance plot curve V, the region greatly affected by the ion conduction resistance of the cathode 52, and the ion This is a boundary point with a region that is hardly affected by conduction resistance. In other words, the turning point P is a point in the complex impedance plot curve V where the slope of the tangent line (the amount of change of the imaginary part value Z2 with respect to the real part value Z1) is equal to or greater than a predetermined threshold value. This threshold value is set in advance based on a specific design of the fuel cell, for example, the following (A) to (C).
(A) In a fuel cell, a cathode manufacturing method (catalyst ink dispersion method, coating method, etc.).
(B) The type, amount, thickness direction and surface direction of the ionomer in the cathode.
(C) The type and particle size of the catalyst metal support in the cathode.

  Returning to FIG. 4, after execution of step S320, the CPU 12 estimates the ionomer distribution in the thickness direction at the cathode 52 of the fuel cell (MEA) based on the complex impedance plot curve V calculated in step S320 ( Step S330). Here, the “thickness direction” is the thickness direction of the cathode 52.

  FIG. 7 is an enlarged view of the vicinity of the turning point P in the complex impedance plot curve V. FIG. The distribution of the ionomer is estimated based on an angle θ of an angle formed by a tangent line at a predetermined point on the higher frequency side than the turning point P and a line segment parallel to the real part axis in the complex impedance plot curve V. The Specifically, the estimation is performed based on the following idea. The “higher frequency side than the turning point P” refers to a range of 10 Hz to 1 kHz, for example.

  That is, when the angle θ is within a range of 45 ° ± α (α: error constant), it is considered that the ion conduction resistance of the ionomer is almost uniform in the thickness direction of the cathode, and the angle θ is 45 ° + α. In the cathode thickness direction, it is considered that the ion conduction resistance of the ionomer on the electrolyte membrane side is lower than that on the gas diffusion layer side, while the angle θ is smaller than 45 ° -α. It is considered that the ion conduction resistance of the ionomer film on the electrolyte membrane side is higher than that on the gas diffusion layer side in the thickness direction of the cathode. The error constant α may be a minute positive value, and takes a value in the range of 0.1 to 1.0, for example.

  Therefore, when the angle θ is within the range of 45 ° ± α, the CPU 12 distributes the ionomer substantially uniformly in the thickness direction of the cathode (hereinafter, this ionomer distribution is referred to as “pattern A”). In the case where the angle θ is larger than 45 ° + α, more ionomers are distributed in the electrolyte membrane 51 side than in the gas diffusion layer 60 side in the thickness direction of the cathode (hereinafter, this ionomer distribution). And the angle θ is smaller than 45 ° −α, the ionomer is distributed more on the gas diffusion layer 60 side than on the electrolyte membrane 51 side in the thickness direction of the cathode. (Hereinafter, this ionomer distribution is referred to as “pattern C”).

  Next, the CPU 12 displays the ionomer distribution obtained in step S330 as an evaluation result on the display unit 19 via the input / output control unit 18 (step S340). That is, the display unit 19 displays which of the patterns A to C is applicable. After execution of step S340, the fuel cell evaluation process is terminated.

  In step S190 in FIG. 2, the operator can know the ionomer distribution of the fuel cell CL from the evaluation result displayed on the display unit 19 of the fuel cell evaluation device 10. The “ionomer distribution” referred to here is an ionomer distribution in the thickness direction of the cathode 52 as described above. In this specification, the term “ionomer distribution” or “ionomer distribution” simply means the ionomer distribution in the thickness direction of the cathode.

  Subsequently, the operator determines whether or not the evaluation result obtained by the fuel cell evaluation device 10 matches a previously intended ionomer distribution (hereinafter referred to as “target distribution”) (step S200). Here, if it is determined that they match, the worker assumes that the fuel cell CL manufactured in step S170 is suitable, and the fuel cell CL is completed. In the case of a fuel cell, the ionomer distribution in the thickness direction of the cathode does not uniquely determine which of the patterns A to C is good, and which pattern is good depending on the mode of use and the like. That will change. In this embodiment, a pattern A having a substantially uniform ionomer distribution is set as a target distribution, and in step S200, it is determined whether or not it matches the target distribution.

  On the other hand, if it is determined in step S200 that the evaluation result obtained by the fuel cell evaluation device 10 is not the pattern A, the created fuel cell CL is not intended, and the operator The fuel cell CL created in step S170 is discarded (step S210), and a new catalyst ink creation process for creating a new catalyst ink is executed (step S220). Thereafter, the operator returns to the process of step S130 and re-executes steps S130 to S170, thereby re-creating the fuel cell CL using the new catalyst ink created by the new catalyst ink creation process.

  Thereafter, the operator evaluates whether or not the newly-created new fuel cell CL is appropriate by executing the processing after step S180 again. Then, by repeating Steps S200 to S220 and Steps S130 to 200, a fuel cell in which the ionomer distribution becomes the target distribution is manufactured.

  FIG. 8 is a flowchart showing a new catalyst ink creation process. As shown in the figure, the operator firstly, as in the process of step S110 (FIG. 2), an electrolyte (for example, a fluororesin), a solvent (for example, water, alcohol, etc.), and a catalyst metal-supporting carrier (for example, And ketjen black carrying platinum) and a Teflon (registered trademark) base material are prepared (step S410).

  Next, the operator determines whether the evaluation result obtained in step S190 is either pattern B or pattern C, that is, on which side the ionomer is unevenly distributed (step S420). Here, when it is determined that the gas diffusion layer 60 is largely distributed on the gas diffusion layer 60 side, the operator determines that the ratio of the solid content of the catalyst ink is the previously created catalyst ink (in this case, when the ink was created in step S110). A catalyst ink that is higher than the catalyst ink is created (step S430). Here, the “solid content ratio” is a value obtained by dividing the weight of the solute (weight of the catalyst metal-supported carrier and ionomer) by the weight of the entire ink, and is expressed, for example, as a percentage. The “solid content ratio” is hereinafter referred to as “solid content ratio”. The preparation of the catalyst ink is performed by mixing the electrolyte prepared in step S410, the solvent, and the catalyst metal-supported carrier. Here, the amount of the solvent is adjusted to increase the solid content ratio.

  The present inventor has found that the solid content ratio of the catalyst ink correlates with the ionomer distribution in the thickness direction at the cathode. Therefore, in this embodiment, the ionomer distribution in the thickness direction at the cathode is controlled by changing the solid content ratio of the catalyst ink. It is clear from the results of the following confirmation test that the ionomer distribution can be controlled by changing the solid content ratio.

  FIG. 9 is a diagram for Table TBL1 showing the relationship between the solid content ratio of the catalyst ink and the tangent angle θ in the complex impedance plot curve V. FIG. As shown in the figure, the present inventor conducted three kinds of confirmation tests, “confirmation test 1”, “confirmation test 2”, and “confirmation test 3”. In each confirmation test, a catalyst ink having a solid content ratio shown in Table TBL1 is created, a fuel cell is created using the created catalyst ink, and an ionomer distribution of the fuel cell is evaluated. This evaluation is performed based on the same principle as that of the fuel cell evaluation apparatus 10 described above, and the above-described angle θ of the tangent in the complex impedance plot curve V is detected.

  In each of the confirmation tests 1 to 3, 1 g of carbon fine particles (Ketjen Black EC: manufactured by Ketjen Black International Co.) carrying 45% by mass of platinum was used as the catalyst metal carrier, and the polymer electrolyte was used as the electrolyte. (SE20092: manufactured by DuPont) 2.2 g is used. From Table TBL1, when the solid content ratio of the catalyst ink is 5%, the angle θ is 36 degrees, and when the solid content ratio of the catalyst ink is 10%, the angle θ is 42 degrees, It can be seen that when the fraction is 20 percent, the angle θ is 45 degrees. If the solid content ratio of the catalyst ink exceeds 20%, the viscosity is too high and the coating accuracy becomes low. Therefore, in this embodiment, the maximum solid content ratio of the catalyst ink is set to 20%.

  When the solid content ratio of the catalyst ink decreases, the amount of solvent per unit volume increases, so that the amount of ionomer present in the solvent is expected to increase. For this reason, the amount of ionomer that moves with the solvent during coating and drying increases, and it is estimated that the ionomer distribution tends to be unevenly distributed. On the other hand, when the solid content ratio of the catalyst ink is appropriate, the ionomer is difficult to move, so that the ionomer distribution is uniform.

From the above confirmation tests 1 to 3 and the above consideration, the following (I) and (II) can be understood.
(I) By setting the solid content ratio of the catalyst ink to a predetermined value Sa or more, the ionomer distribution in the thickness direction at the cathode can be made substantially uniform. Here, the predetermined value Sa is less than 20% and close to 20%.
(II) By adjusting the solid content ratio of the catalyst ink within a range below the predetermined value Sa, the ionomer distribution can be arbitrarily controlled from a substantially uniform state to a state in which it is unevenly distributed on the gas diffusion layer side. .

  Therefore, in step S430, in detail, the operator creates a catalyst ink having a solid content ratio that is higher by a predetermined value ΔSI than the solid content ratio SI of the previously created catalyst ink. Here, the “previously created catalyst ink” is the catalyst ink created in step S110 when the new catalyst ink creation process is executed for the first time, and this new catalyst ink creation process was executed for the second and subsequent times. Sometimes it is the catalyst ink created in step S430 at the previous execution of the new catalyst ink creation process. The predetermined value ΔSI is a minute value, for example, 2%.

  On the other hand, when it is determined in step S420 that the evaluation result shows that the ionomer distribution is unevenly distributed on the gas diffusion layer 60 side, the operator creates a catalyst ink having a solid content ratio of 20% ( Step S440). That is, by setting the solid content ratio to 20%, a catalyst ink is prepared so that the ionomer distribution is substantially uniform.

  After step S430 or step S is executed, the new catalyst ink creation process is temporarily terminated. Thereafter, the fuel cell CL is recreated using the newly created catalyst ink as described above. As a result, it is possible to reliably manufacture a fuel cell including a cathode having a substantially uniform ionomer distribution.

  In the fuel cell manufacturing method and the fuel cell evaluation process, the processes in steps S110 and S120 correspond to the “catalyst ink preparation process” in application example 1, and the processes in steps S130 and S140 are performed in “application example 1”. Corresponding to the “first electrode creation process”, the processes of steps S150 and S160 correspond to the “membrane electrode assembly creation process” in application example 1, and the process of step S170 corresponds to the “fuel cell creation process” in application example 1. The process of step S310 corresponds to the “measurement process” in application example 1, the processes of steps S320 and S330 correspond to the “estimation process” in application example 1, and the processes of steps S200 and S220 are the “feedback” in application example 1. Corresponds to "Process".

  In this embodiment, the aim is to produce a fuel cell having a cathode in which ionomers are distributed substantially uniformly in the thickness direction, but instead, a gas diffusion layer is formed in the thickness direction more than the electrolyte membrane 51 side. It may be aimed to manufacture a fuel cell having a cathode 52 in which a large amount of ionomers are distributed on the 60 side. That is, the pattern C in which the ionomer distribution is larger on the gas diffusion layer 60 side than on the electrolyte membrane 51 side can be set as the target distribution. In this case, the operator may create a catalyst ink having a solid content ratio that is lower than the solid content ratio SI of the previously created catalyst ink by a predetermined value ΔSI. With this configuration, it is possible to manufacture a fuel cell including a cathode in which more ionomers are distributed on the gas diffusion layer 60 side than on the electrolyte membrane 51 side.

  In this embodiment, as a result of the solid content ratio of the catalyst ink being lowered and the ionomer distribution becoming more unevenly distributed, the ionomer is more distributed on the gas diffusion layer 60 side in the cathode 52 than on the electrolyte membrane 51 side. This is because it is determined in such a manner from the method of coating and drying and the positional relationship of the cathode 52 with respect to the electrolyte membrane 51 during hot pressing. For example, the positional relationship of the cathode 52 with respect to the electrolyte membrane 51 during hot pressing is opposite to the relationship in which the cathode is positioned below the electrolyte membrane, that is, the relationship where the cathode is positioned above the electrolyte membrane. In other words, the ionomer is more distributed in the cathode 52 than on the gas diffusion layer 60 side, in other words, the tangent angle θ in the complex impedance plot curve V exceeds 45 degrees. It is also possible to control the range.

A-3. effect:
As described in detail above, according to the fuel cell manufacturing method of the first embodiment, the cathode provided in the fuel cell CL based on the complex impedance plot curve V obtained from the measured AC impedance for each frequency. The ionomer distribution in the thickness direction of the cathode is estimated and the solid content ratio of the catalyst ink at the time of catalyst ink preparation is obtained based on the estimated ionomer distribution (that is, the estimation result is fed back to catalyst ink preparation). The ionomer distribution is controlled to the target distribution. Therefore, according to the fuel cell evaluation method, a fuel cell having an appropriate ionomer distribution at the cathode 52 can be manufactured.

  In particular, in this embodiment, when it is evaluated that the ionomer distribution is unevenly distributed on the gas diffusion layer 60 side, a new catalyst ink is created by increasing the solid content ratio by a minute value ΔSI. Since the fuel cell is created again and then the fuel cell is evaluated again, the ionomer distribution at the cathode 52 can be adjusted to the target distribution with high accuracy.

B. Second embodiment:
Next, a second embodiment of the present invention will be described. In the first embodiment, based on the knowledge that the solid content ratio of the catalyst ink has a correlation with the ionomer distribution in the thickness direction at the cathode, the ionomer distribution is controlled by changing the solid content ratio of the catalyst ink. It was. In contrast, the second embodiment is based on the knowledge that the preparation procedure of the catalyst ink is correlated with the ionomer distribution, and the ionomer distribution is controlled by changing the preparation procedure of the catalyst ink. . Details will be described below.

  FIG. 10 is a diagram for the table TBL2 showing the relationship between the catalyst ink preparation procedure and the tangent angle θ in the complex impedance plot curve V. FIG. Three confirmation tests of “confirmation test 11”, “confirmation test 12”, and “confirmation test 13” were performed, and the preparation procedure and the measurement result of the angle θ in each confirmation test are shown in Table TBL2.

In confirmation test 11,
(I) 1 g of carbon fine particles (Ketjen Black EC: manufactured by Ketjen Black International) carrying 45% by mass of platinum and water are mixed,
(Ii) 2.2 g of polymer electrolyte (SE20092: manufactured by DuPont) is mixed with the mixture of (i),
(Iii) Ethanol was mixed with the mixture of (ii) to prepare a catalyst ink having a solid content of 10%. This preparation procedure of the catalyst ink is referred to as “creation procedure A”.

In confirmation test 12,
(I) 1 g of carbon fine particles (Ketjen Black EC: manufactured by Ketjen Black International) carrying 45% by mass of platinum and water are mixed,
(Ii) 2.2 g of polymer electrolyte (SE20092: manufactured by DuPont) and ethanol were mixed,
(Iii) The mixture of (i) and the mixture of (ii) were mixed to prepare a catalyst ink having a solid content of 10%. This preparation procedure of the catalyst ink is referred to as “creation procedure B”.

In confirmation test 13,
(I) 1 g of carbon fine particles (Ketjen Black EC: manufactured by Ketjen Black International) carrying 45% by mass of platinum and water are mixed,
(Ii) mixing ethanol with the mixture of (i),
(Iii) A polymer ink (SE20092: manufactured by DuPont) (2.2 g) was mixed with the mixture of (ii) to prepare a catalyst ink having a solid content of 10%. This preparation procedure of the catalyst ink is referred to as “creation procedure C”.

  As shown in Table TBL2 of FIG. 10, when the catalyst ink is prepared by the preparation procedure A, the tangent angle θ described above in the complex impedance plot curve V is 44 degrees. When the catalyst ink is prepared by the preparation procedure B, the tangent angle θ is 35 degrees. When the catalyst ink is prepared by the preparation procedure C, the angle θ of the tangent line is 41 degrees.

  From these facts, it can be seen that when the preparation procedure of the catalyst ink is changed to any of the preparation procedures A to C, the ionomer distribution changes in a state where the ionomer distribution is biased toward the gas diffusion layer. As shown in preparation procedure A, (i) a catalyst metal-supported support and water are mixed, (ii) an ionomer is mixed with the mixture of (i), (iii) an alcohol is added to the mixture of (ii), and a catalyst is prepared. By creating the ink, the ionomer distribution can be changed to a state that is slightly biased toward the gas diffusion layer side. In addition, as shown in preparation procedure B, (i) a catalyst metal-supported carrier and water are mixed, (ii) an ionomer is mixed with alcohol, and (iii) a mixture of (i) and a mixture of (ii) are mixed. Thus, by preparing the catalyst ink, the ionomer distribution can be changed to a state that is largely biased toward the gas diffusion layer. In addition, as shown in Preparation Procedure C, (i) a catalyst metal-supported carrier and water are mixed, (ii) an alcohol is mixed with the mixture of (i), and an ionomer is mixed with the mixture of (iii) (ii). By preparing the catalyst ink, the ionomer distribution can be changed to a state that is moderately biased toward the gas diffusion layer side.

  The mechanism by which the ionomer distribution is changed by changing the preparation procedure of the catalyst ink as described above is unknown, but it is presumed to be related to the interaction between the solvent and the ionomer. That is, the distribution of ionomers interacts with both the solvent and carbon, but it seems that a large amount can remain in the solvent by preferentially acting on either of them. When much remains in the solvent, it is estimated that it can move with the solvent during the coating / drying process and the distribution can be biased.

  The fuel cell manufacturing method of the second embodiment is different from the fuel cell manufacturing method of the first embodiment only in the content of the new catalyst ink preparation process, and the other configurations are the same. The processing shown in FIG. 2 is the same, and this second embodiment is executed in the same manner as in the first embodiment.

  FIG. 11 is a flowchart showing a new catalyst ink creation process in the second embodiment. As shown in the drawing, the operator first prepares an electrolyte, a solvent, a catalyst metal carrier, and a base material (step S510), similarly to steps S410 and S420 (FIG. 8) in the first embodiment, and step S190. It is determined whether the evaluation result obtained by the pattern B or the pattern C, that is, on which side the ionomers are unevenly distributed (step S520).

  When it is determined in step S520 that the gas diffusion layer 60 is largely unevenly distributed, the operator has a degree of bias of the ionomer distribution of 1 compared to the catalyst ink preparation procedure at the time of the previous catalyst ink preparation. A creation procedure that is smaller by one step is selected from the creation procedures A to C, and a catalyst ink is created by the selected creation procedure (step S530). Specifically, the operator selects “creation procedure C” when the creation procedure at the previous catalyst ink creation is “creation procedure B”, and the creation procedure at the previous catalyst ink creation is “ In the case of “creation procedure C”, “creation procedure A” is selected. Here, “when the previous catalyst ink is created” means that when this new catalyst ink creation process is executed for the first time, the catalyst ink is created in step S110, and this new catalyst ink creation is performed after the second time. When the process is executed, it is the previous execution of the new catalyst ink creation process.

  Note that if the preparation procedure at the time of preparation of the previous catalyst ink is “creation procedure A”, the ionomer distribution cannot be controlled to the uniform side only by switching the creation procedures A to C. The process for creating the catalyst ink is stopped.

  On the other hand, when it is determined in step S520 that the evaluation result shows that the ionomer distribution is unevenly distributed on the gas diffusion layer 60 side, the worker creates catalyst ink according to “creation procedure A” (step S520). S540). That is, the catalyst ink is prepared by the preparation procedure A that minimizes the degree of bias of the ionomer distribution among the preparation procedures A to C.

  In the second embodiment, the aim is to produce a fuel cell having a cathode in which ionomers are distributed substantially uniformly in the thickness direction, but instead, from the electrolyte membrane 51 side in the thickness direction. Alternatively, it may be aimed to manufacture a fuel cell including the cathode 52 in which a large amount of ionomer is distributed on the gas diffusion layer 60 side. That is, the pattern C in which the ionomer distribution is larger on the gas diffusion layer 60 side than on the electrolyte membrane 51 side can be set as the target distribution. In this case, the operator can select a creation procedure from creation procedures A to C that has a greater degree of bias in the ionomer distribution than the creation procedure of the catalyst ink at the previous creation of the catalyst ink. Good. With this configuration, it is possible to manufacture a fuel cell including a cathode in which more ionomers are distributed on the gas diffusion layer 60 side than on the electrolyte membrane 51 side.

  According to the fuel cell manufacturing method of the second embodiment configured as described above, a fuel cell with an appropriate ionomer distribution at the cathode 52 can be manufactured as in the first embodiment. In particular, in this embodiment, it is possible to easily adjust the ionomer distribution in the cathode 52 by changing the preparation procedure of the catalyst ink.

C. Third embodiment:
Next, a third embodiment of the present invention will be described. In the third embodiment, the SP value (solubility parameter: also referred to as solubility parameter or solubility parameter) of the solvent used for the preparation of the catalyst ink has a correlation with the ionomer distribution in the thickness direction at the cathode. Thus, the ionomer distribution is controlled by changing the type of solvent of the catalyst ink. This is because the SP value can be changed by changing the solvent type of the catalyst ink. Details will be described below.

  FIG. 12 is a diagram for the table TBL3 showing the relationship between the SP value of the solvent and the tangent angle θ in the complex impedance plot curve V. Three types of confirmation tests, “Confirmation Test 21”, “Confirmation Test 22”, and “Confirmation Test 23”, were performed. It was shown to.

  In the confirmation test 21, a solvent having an SP value of 19.5 is prepared with the type and composition ratio of the solvent shown, a cathode is prepared from the catalyst ink prepared using the solvent, and a fuel cell is connected from the cathode. The measurement result that the angle θ is 57 degrees was obtained by measuring the angle θ of the tangent in the complex impedance plot curve V for the fuel cell.

  In the confirmation test 22, a solvent having an SP value of 12 is prepared with the type and composition ratio of the solvent shown in the figure, a cathode is prepared from the catalyst ink prepared using the solvent, and a fuel cell is prepared from the cathode. By measuring the angle θ of the tangent in the complex impedance plot curve V for the fuel cell, a measurement result that the angle θ is 47 degrees was obtained.

  In the confirmation test 23, a solvent having an SP value of 10 was prepared with the type and composition ratio of the solvent shown in the figure, a cathode was prepared from the catalyst ink prepared using the solvent, and a fuel cell was prepared from the cathode. By measuring the angle θ of the tangent in the complex impedance plot curve V for the fuel cell, a measurement result that the angle θ was 43 degrees was obtained. In each of confirmation tests 21 to 23, the ionomer amount is constant at I / C = 0.75. Here, “I” is the weight of ionomer, and “C” is the weight of carbon.

  From these, by changing the type of solvent and increasing the SP value, the ionomer distribution can be changed to a more distributed state on the electrolyte membrane side than on the gas diffusion layer side, and the type of solvent can be changed. It can be seen that the ionomer distribution can be changed to a state in which the ionomer distribution is distributed more on the gas diffusion layer side than on the electrolyte membrane side by lowering the SP value.

  The fuel cell manufacturing method of the third embodiment is different from the fuel cell manufacturing method of the first embodiment only in the contents of the new catalyst ink preparation process, and the other configurations are the same. The processing shown in FIG. 2 is the same, and this third embodiment is executed in the same manner as in the first embodiment.

  FIG. 13 is a flowchart showing a new catalyst ink creation process in the third embodiment. As shown in the drawing, the operator firstly, like the processing in step S410 (FIG. 8) in the first embodiment, an electrolyte (for example, a fluororesin), a solvent (for example, water, alcohol, etc.), a catalyst A metal-supported carrier (for example, one in which platinum is supported on ketjen black) and a base material made of Teflon (registered trademark) are prepared (step S610).

  Next, the operator determines a catalyst ink creation procedure based on the evaluation result obtained in step S190 (FIG. 2), and creates a catalyst ink according to the determined creation procedure (step S620). Specifically, the creation procedure is determined according to the following (a) and (b). Here, a pattern A having a substantially uniform ionomer distribution will be described as a target distribution.

(A) When the evaluation result obtained in step S190 is “pattern B”, that is, when more ionomers are distributed on the electrolyte membrane 51 side than on the gas diffusion layer 60 side, to reduce the angle θ, The catalyst ink is prepared by changing the solvent type to a type having an SP value lower than the SP value of the solvent used in the previous catalyst ink preparation.

(B) When the evaluation result obtained in step S190 is “pattern C”, that is, when more ionomers are distributed on the gas diffusion layer 60 side than on the electrolyte membrane 51 side, to increase the angle θ, The catalyst ink is created by changing the solvent type to a type having an SP value higher than the SP value of the solvent used at the previous creation of the catalyst ink.

  Since it is determined in step S200 (FIG. 2) that the evaluation result is not the target distribution, the evaluation result does not become “pattern A” at the time of step S520. After the execution of step S620, the new catalyst ink creation process is temporarily terminated. Thereafter, similar to the first embodiment, the fuel cell CL is recreated using the newly created catalyst ink. As a result, it is possible to reliably manufacture a fuel cell including a cathode having a substantially uniform ionomer distribution.

  In the third embodiment, the aim is to produce a fuel cell having a cathode in which ionomers are distributed substantially uniformly in the thickness direction. Instead, the gas diffusion layer 60 side in the thickness direction is intended. In addition, it may be aimed to manufacture a fuel cell having a cathode in which more ionomers are distributed on the electrolyte membrane 51 side. That is, the pattern B in which the ionomer distribution is larger on the electrolyte membrane 51 side than on the gas diffusion layer 60 side can be set as the target distribution. In this case, in the process of step S520, the operator changes the solvent type to a type having an SP value higher than the SP value of the currently used solvent in order to increase the angle θ. Create ink.

  It can also be aimed to manufacture a fuel cell including a cathode in which more ionomer is distributed on the gas diffusion layer 60 side than on the electrolyte membrane 51 side in the thickness direction. That is, the pattern C in which the ionomer distribution is larger on the gas diffusion layer 60 side than on the electrolyte membrane 51 side can be set as the target distribution. In this case, in order to reduce the angle θ, the operator changes the solvent type to a type that has an SP value lower than the SP value of the currently used solvent, and creates catalyst ink.

  According to the method of manufacturing the fuel cell of the third embodiment configured as described above, a fuel cell with an appropriate ionomer distribution at the cathode 52 can be manufactured as in the first and second embodiments. . In particular, in this embodiment, it is possible to easily adjust the ionomer distribution at the cathode 52 by changing the SP value of the solvent for forming the catalyst ink.

D. Variation:
It should be noted that elements other than those described in the independent claims among the constituent elements in the first to third embodiments and the modifications described above are additional elements and can be omitted as appropriate. The present invention is not limited to the above-described embodiments and modifications, and can be carried out in various modes without departing from the scope of the invention. For example, the following modifications are possible. is there.

D1. Modification 1:
In the first to third embodiments, the fuel cell manufacturing method is performed by a worker who is a person, but instead, it may be configured such that the work performed by the worker is automated by an automation device. . According to this configuration, an appropriate fuel cell can be created more easily.

D2. Modification 2:
In the fuel cell manufacturing method of each of the above embodiments, when estimating the electrolyte distribution in the thickness direction of the cathode of the manufactured fuel cell, the complex impedance plot curve V has a predetermined point on the higher frequency side than the turning point P. Is estimated based on the angle θ of the angle formed by the tangent line and the line segment parallel to the real part axis, but the present invention is not limited to this. For example, in the complex impedance plot curve V, a straight line (for example, a line connecting two points, an approximate straight line of three points, etc.) obtained by a plurality of points on the higher frequency side than the turning point P, and a line segment parallel to the real part axis The electrolyte distribution in the thickness direction of the cathode may be estimated based on the angle θ of the angle formed by. Even if it does in this way, there can exist an effect similar to the said Example.

D3. Modification 3:
In the method of manufacturing the fuel cell of the embodiment, when estimating the electrolyte distribution in the thickness direction of the cathode 52, the tangent line at a predetermined point on the higher frequency side than the turning point P in the complex impedance plot curve V, and the real part Although the estimation is made based on the angle θ formed by the line segment parallel to the axis, the present invention is not limited to this. For example, a straight line obtained by a plurality of plot points corresponding to a frequency (for example, 10 Hz to 1 kHz) higher than the frequency corresponding to the turning point P in the complex impedance plot curve V (for example, a line connecting two points and an approximate straight line of three points) Etc.) and the angle θ of the angle formed by the line segment parallel to the real part axis, the electrolyte distribution in the thickness direction of the cathode 52 may be estimated. Even if it does in this way, there can exist an effect similar to the said Example.

D4. Modification 4:
In the fuel cell manufacturing method of the above embodiment, the electrolyte distribution in the thickness direction of the cathode is estimated based on the AC impedance (complex impedance plot curve V) at each frequency in the manufactured fuel cell, and the estimation result However, when the distribution state is not intended, a new cathode is newly manufactured based on the estimation result, and a new fuel cell is manufactured. However, the present invention is not limited to this. . For example, in the manufactured fuel cell, when the electrolyte distribution in the thickness direction of the anode is estimated based on the AC impedance (complex impedance plot curve V) at each frequency, and the estimation result is not the intended distribution state Based on the estimation result, a new anode may be remanufactured and a new fuel cell may be manufactured. In this case, the complex impedance plot curve V is detected in a state where nitrogen as an inert gas is introduced into the anode of the fuel cell and hydrogen as the active gas is introduced into the cathode. By doing so, it is possible to manufacture a fuel cell having an anode in which the distribution state of the electrolyte in the thickness direction is the intended distribution state.

D5. Modification 5:
In the fuel cell manufacturing method of each of the above embodiments, the complex impedance plot curve V is detected in a state where hydrogen as an active gas is introduced into the anode of the fuel cell and nitrogen as an inert gas is introduced into the cathode. However, the present invention is not limited to this. For example, an inert gas (for example, nitrogen) may be introduced into the anode of the fuel cell, and the complex impedance plot curve V may be detected in that state. Even if it does in this way, there can exist the effect of the said Example.

D6. Modification 6:
In the fuel cell manufacturing method of each of the above embodiments, a gas having a relative humidity higher than 60% may be used for hydrogen and nitrogen introduced into the fuel cell. Even in this case, at least a part of the effect of the embodiment can be achieved.

D7. Modification 7:
In the fuel cell manufacturing method of each of the above embodiments, when a new MEA is manufactured, the ratio of the solid content of the catalyst ink is adjusted based on the estimation result of the electrolyte distribution in the thickness direction of the cathode, or the catalyst ink However, the present invention is not limited to this, although the production procedure is changed or the SP value of the solvent used for producing the catalyst ink is adjusted to produce a new MEA. For example, when manufacturing a new MEA, based on the estimation result of the electrolyte distribution in the thickness direction of the cathode, the ratio of the solid content of the catalyst ink, the preparation procedure of the catalyst ink, and other preparation conditions other than the SP value of the solvent ( For example, a new MEA may be manufactured by adjusting the ionomer mixing method. Even if it does in this way, there can exist the effect of the said Example.

D8. Modification 8:
The manufacturing method of the fuel cell in each of the above embodiments is an aspect as a manufacturing method of a fuel battery cell, but instead of this, as an aspect as a method of manufacturing a fuel battery stack in which a plurality of fuel battery cells are stacked. Good. In addition, the fuel cell to be manufactured is a solid polymer fuel cell in each embodiment, but is not limited thereto, and various types such as a solid oxide fuel cell electrolyte type and a molten carbonate electrolyte type are available. The fuel cell may be used.

10 ... Fuel cell evaluation device 12 ... CPU
14 ... ROM
16 ... RAM
DESCRIPTION OF SYMBOLS 18 ... Input / output control part 19 ... Display part 20 ... 1st wiring 30 ... 2nd wiring 51 ... Electrolyte membrane 52 ... Cathode 53 ... Anode 60 ... Gas diffusion layer 70 ... Gas diffusion layer 80 ... Separator 82 ... In-cell flow Path 82a ... Convex part 82b ... Concave part 90 ... Separator 92 ... Channel in cell 92a ... Convex part 92b ... Concave part 103-106 ... Hole part 110 ... Seal member CL ... Fuel cell V ... Complex impedance plot curve θ ... Angle

Claims (6)

A fuel cell manufacturing method comprising:
A catalyst ink production step of producing a catalyst ink containing an ionomer under predetermined production conditions;
A first electrode creating step of creating a first electrode using the catalyst ink;
A membrane electrode assembly creating step of creating a membrane electrode assembly in which the first electrode is disposed on one surface of the electrolyte membrane and the second electrode is disposed on the other surface of the electrolyte membrane;
A fuel cell creating step of creating a fuel cell in which a gas diffusion layer and a separator are laminated on the membrane electrode assembly;
A measurement step of measuring the AC impedance of the membrane electrode assembly provided in the fuel cell while changing the frequency;
An estimation step for estimating a distribution of the ionomer in the thickness direction of the first electrode in the first electrode based on the AC impedance for each frequency measured in the measurement step;
A fuel cell manufacturing method comprising: a feedback step of adjusting the creation conditions in the catalyst ink creation step so that the ionomer distribution obtained in the estimation step becomes a target distribution. In the manufacturing method of the fuel cell according to claim 1,
The predetermined preparation condition is a condition regarding the ratio of the solid content of the catalyst ink,
The method of manufacturing a fuel cell, wherein the feedback step includes a configuration for adjusting a solid content ratio of the catalyst ink. In the manufacturing method of the fuel cell according to claim 1,
The predetermined preparation condition is a condition for a preparation procedure of the catalyst ink,
The method of manufacturing a fuel cell, wherein the feedback step includes a configuration that changes a preparation procedure of the catalyst ink. In the manufacturing method of the fuel cell according to claim 1,
The predetermined preparation condition is a condition for the SP value of the solvent used for preparation of the catalyst ink,
A feedback process is a manufacturing method of a fuel cell including the structure which adjusts SP value of the said solvent. In the manufacturing method of the fuel cell in any one of Claims 1 thru | or 4,
The estimation step includes
A method for manufacturing a fuel cell, wherein the measurement is performed with an inert gas introduced into a first electrode of a membrane electrode assembly provided in the fuel cell. In the manufacturing method of the fuel cell in any one of Claims 1 thru | or 5,
The estimation step includes
A step of obtaining a complex impedance plot curve from each plot point in which AC impedance at each frequency measured in the measurement step is entered in a complex plane;
Estimating a distribution of the ionomer in the thickness direction of the first electrode in the first electrode based on the complex impedance plot curve.

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