Method of and apparatus for producing membrane electrode assembly
10971749 ยท 2021-04-06
Assignee
Inventors
- Hiroyuki Nakatsuka (Tochigi-ken, JP)
- Seiichi Kouketsu (Tochigi-ken, JP)
- Masaya Igaki (Tochigi-ken, JP)
Cpc classification
H01M8/0297
ELECTRICITY
Y02P70/50
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H01M8/04731
ELECTRICITY
Y02E60/50
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
International classification
H01M8/0297
ELECTRICITY
Abstract
A method of producing an MEA includes a first joining step of joining an anode to one surface of a solid polymer electrolyte membrane to thereby form a joint body and a second joining step of joining a cathode to another surface of the solid polymer electrolyte membrane. In the first joining step, the solid polymer electrolyte membrane is attracted by suction and heated through the anode placed on a suction/heating surface of a suction/heating plate. In the second joining step, a stack body of the joint body and the cathode is pressed and heated in a stacking direction, between the suction/heating surface and a heating plate.
Claims
1. A method of producing a membrane electrode assembly including a solid polymer electrolyte membrane, a porous first electrode and a porous second electrode, the first electrode and the second electrode being joined to respective both sides of the solid polymer electrolyte membrane, the first electrode and the second electrode each including a gas diffusion layer and an electrode catalyst layer, the method comprising: a first joining step of attracting by suction and heating the solid polymer electrolyte membrane stacked on the first electrode, through the first electrode placed on a suction/heating surface of a suction/heating plate having a suction unit and a heating unit, and then joining the first electrode to one surface of the solid polymer electrolyte membrane to thereby form a joint body; and a second joining step of pressing and heating a stack body including the solid polymer electrolyte membrane of the joint body and the second electrode stacked together, in a stacking direction between the suction/heating surface and a heating plate, to thereby join the second electrode to another surface of the solid polymer electrolyte membrane.
2. The method of producing the membrane electrode assembly according to claim 1, further comprising, between the first joining step and the second joining step, the steps of: transferring the joint body from the suction/heating surface to a transportation unit; after the joint body is transferred from the suction/heating surface, placing the second electrode on the suction/heating surface and attracting the second electrode by suction to the suction/heating surface; and stacking the joint body on the second electrode attracted to the suction/heating surface by suction, to thereby form the stack body, wherein, in the second joining step, the stack body is pressed and heated in a state where the solid polymer electrolyte membrane is attracted by suction through the second electrode.
3. The method of producing the membrane electrode assembly according to claim 1, wherein the heating plate is configured to attract the second electrode by suction, the method further comprising, between the first joining step and the second joining step, the step of, in a state where the joint body is attracted to the suction/heating surface by suction, moving the heating plate with the second electrode being attracted by suction thereto, closer to the joint body, and then stacking the joint body and the second electrode together to thereby form the stack body, wherein, in the second joining step, in a state where the solid polymer electrolyte membrane is attracted by suction through the first electrode and the second electrode by the suction/heating surface and the heating plate, the stack body is pressed and heated by the suction/heating surface and the heating plate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
DESCRIPTION OF THE PREFERRED EMBODIMENTS
(14) Hereinafter, preferred embodiments of a method of and an apparatus for producing a membrane electrode assembly according to the present invention will be described with reference to the accompanying drawings.
(15)
(16) The anode 14 includes a first electrode catalyst layer 14a joined to one surface 12a of the solid polymer electrolyte membrane 12, and a first gas diffusion layer 14b stacked on the first electrode catalyst layer 14a. The first electrode catalyst layer 14a and the first gas diffusion layer 14b have the same surface size or planar size. The surface size of the first electrode catalyst layer 14a and the surface size of the first gas diffusion layer 14b are the same as or less than the surface size of the solid polymer electrolyte membrane 12.
(17) The cathode 16 includes a second electrode catalyst layer 16a joined to a surface 12b of the solid polymer electrolyte membrane 12, and a second gas diffusion layer 16b stacked on the second electrode catalyst layer 16a. The second electrode catalyst layer 16a and the second gas diffusion layer 16b have the same outer size.
(18) Further, the surface size (outer size) of the cathode 16 is smaller than the surface sizes (outer sizes) of the solid polymer electrolyte membrane 12 and the anode 14. That is, the MEA 10 is the so-called stepped type of MEA, which has different sizes of components. Instead of adopting the above structure, the surface size of the anode 14 may be smaller than the surface sizes of the solid polymer electrolyte membrane 12 and the cathode 16. The anode 14 and the cathode 16 may have substantially the same surface size.
(19) The first electrode catalyst layer 14a includes platinum alloy supported on porous carbon particles, and the carbon particles are deposited uniformly on the surface of the first gas diffusion layer 14b to thereby form the first electrode catalyst layer 14a. The first gas diffusion layer 14b comprises a carbon paper, carbon cloth, etc. The second electrode catalyst layer 16a includes platinum alloy supported on porous carbon particles, and the carbon particles are deposited uniformly on the surface of the second gas diffusion layer 16b to thereby form the second electrode catalyst layer 16a. The second gas diffusion layer 16b comprises a carbon paper, carbon cloth, etc.
(20) Next, an apparatus for producing the membrane electrode assembly according to the first embodiment (hereinafter also simply referred to as the production apparatus) 20 will be described with reference to
(21) For example, the suction/heating plate 26 is a plate of metal, etc. One main surface of the suction/heating plate 26 is a suction/heating surface 26a. The first suction unit 22 includes a plurality of through holes 40 passing through the suction/heating plate 26 in the thickness direction, a chamber 44 formed by a housing 42 attached to a back surface 26b of the suction/heating surface 26a, a vacuum pump 46 for reducing the pressure in the chamber 44, and a connection channel 48 connecting the chamber 44 and the vacuum pump 46.
(22) One end of each of the through holes 40 is opened to the suction/heating surface 26a, and the other end of each of the through holes 40 is connected to the chamber 44. Therefore, in the first suction unit 22, by driving the vacuum pump 46 to reduce the pressure in the chamber 44, a suction target such as the anode 14 can be attracted to the suction/heating surface 26a by suctioning through the through holes 40. The details of the suction target will be described later. It should be noted that the first suction unit 22 is not limited to have the above structure as long as the first suction unit 22 can provide the suction/heating surface 26a with a suction function.
(23) The first heating unit 24 is a heater, etc. provided inside the suction/heating plate 26. For example, it is possible to raise the temperature of the suction/heating surface 26a up to a temperature where the solid polymer electrolyte membrane 12 can be joined to each of the anode 14 and the cathode 16 (hereinafter also referred to as the joining temperature). It should be noted that the first heating unit 24 is not limited to the heater as long as the first heating unit 24 can provide a heating function to the suction/heating surface 26a.
(24) As shown in
(25) Therefore, as described later, the suction/heating plate 26 and the heating plate 30 can heat a stack body 10a interposed between the heating plate 30 and the suction/heating surface 26a up to the joining temperature, and presses the stack body 10a in the stacking direction.
(26) The transportation unit 32 includes transportation plates 50a, 50b having a second suction unit (not shown), and a drive mechanism (not shown) for moving the transportation plates 50a, 50b. Hereinafter, in the case where there is no need to make any distinctions between the transportation plates 50a, 50b, these transportation plates 50a, 50b are also referred to as the transportation plate 50, collectively. For example, the second suction unit has the same structure as the first suction unit 22, and a suction target such as the anode 14 can be attracted to a main surface 52 of the transportation plate 50 by suction. The details of the transportation target will be described later.
(27) That is, in the transportation unit 32, in the state where the transportation target is suctioned and attracted to the main surface 52 by the second suction unit, the transportation plate 50 is moved by the drive mechanism, and thereafter a suctioned state by the second suction unit is released, whereby it is possible to transport the transportation target to a desired position.
(28) The cleaner 34 performs air-suction while blowing away foreign materials, e.g., by an air blow, to thereby remove the foreign materials from the surface of the solid polymer electrolyte membrane 12, the surface of the first electrode catalyst layer 14a of the anode 14, and the surface of the second electrode catalyst layer 16a of the cathode 16 for cleaning.
(29) The cameras 36 capture images of a suction target suctioned on the suction/heating surface 26a of the suction heating plate 26, and/or a transportation target suctioned on the main surface 52 of the transportation plate 50. Based on the image data captured in this process, it is possible to detect the stack position where the suction target and the transportation target are stacked together. Therefore, by moving the transportation unit 32 to the detected stack position, it is possible to stack the suction target and the transportation target in a desired positional relationship.
(30) Next, a production method according to the first embodiment using the production apparatus 20 will be described. Firstly, as shown in
(31) Next, as shown in
(32) Next, as shown in
(33) As described above, since the anode 14 has porosity, the solid polymer electrolyte membrane 12 stacked on the anode 14 is suctioned on the suction/heating surface 26a through the anode 14. By this suction force, the solid polymer electrolyte membrane 12 is pressed against the anode 14, and the state where the anode 14 and the solid polymer electrolyte membrane 12 are stacked together in the desired positional relationship is maintained (the anode 14 and the solid polymer electrolyte membrane 12 are fixedly positioned).
(34) Further, heat of the suction/heating surface 26a heated by the first heating unit 24 is transmitted to the solid polymer electrolyte membrane 12 through the anode 14. At this time, since the shape of the solid polymer electrolyte membrane 12 is maintained by the suction force, thermal deformation of the solid polymer electrolyte membrane 12 is suppressed.
(35) It should be noted that when to raise the temperature of the suction/heating surface 26a by the first heating unit 24 is not limited specially. The temperature of the suction/heating surface 26a may be raised before placing the anode 14 and/or the solid polymer electrolyte membrane 12 on the suction/heating surface 26a. Alternatively, the temperature of the suction/heating surface 26a may be raised after placing the anode 14 and/or the solid polymer electrolyte membrane 12 on the suction/heating surface 26a.
(36) In the state where the anode 14 and the solid polymer electrolyte membrane 12 are attracted by suction, the anode 14 and the solid polymer electrolyte membrane 12 are heated up to the joining temperature, whereby it is possible to join the first electrode catalyst layer 14a of the anode 14 to one surface 12a of the solid polymer electrolyte membrane 12 to thereby form a joint body 60 (first joining step).
(37) Next, as shown in
(38) Further, in the state where the cathode 16 (transportation target) is suctioned and attracted to the main surface 52 of the transportation plate 50b, the cathode 16 is transported by the transportation unit 32. After the joint body 60 is transferred from the suction/heating surface 26a to the transportation plate 50a, the cathode 16 is placed on the suction heating surface 26a (see
(39) Next, as shown in
(40) Next, as shown in
(41) In the stack body 10a formed in the manner as described above, the joint body 60 is suctioned on the suction/heating surface 26a through the porous cathode 16. This suction force maintains the state where the cathode 16 and the joint body 60 are stacked together in the desired positional relationship (the cathode 16 and the solid polymer electrolyte membrane 12 are fixedly positioned).
(42) Next, as shown in
(43) The temperature of the solid polymer electrolyte membrane 12 of the stack body 10a pressed and heated as described above reaches the joining temperature, whereby it is possible to join the second electrode catalyst layer 16a of the cathode 16 and the other surface 12b of the solid polymer electrolyte membrane 12 together (second joining step). As a result, it is possible to obtain the MEA 10 formed by joining the anode 14 and the cathode 16 on respective both sides of the solid polymer electrolyte membrane 12.
(44) That is, in this production method, in the first joining step, the anode 14 is joined to one surface 12a of the solid polymer electrolyte membrane 12 to fixedly position the solid polymer electrolyte membrane 12 and the anode 14 together, and thereafter, in the second joining step, the cathode 16 is joined to the other surface 12b of the solid polymer electrolyte membrane 12. In this manner, for example, in comparison with the case where the anode 14, the solid polymer electrolyte membrane 12, and the cathode 16 are simply stacked together and subjected to hot pressing, it is possible to easily suppress positional deviation between these components.
(45) Further, as described above, in the first joining step, one surface 12a of the solid polymer electrolyte membrane 12 can be pressed against the anode 14 and heated to thereby join the solid polymer electrolyte membrane 12 and the anode 14 together in a manner that structural component parts other than the anode 14 do not contact the solid polymer electrolyte membrane 12. Therefore, even if the anode 14 is joined to one surface 12a of the solid polymer electrolyte membrane 12, for example, unlike the case where hot pressing, etc. is performed using a die (not shown), the solid polymer electrolyte membrane 12 softened by heating is not adhered to the die.
(46) Further, since a suction force from the suction/heating surface 26a is applied to the solid polymer electrolyte membrane 12, in a state where positional deviation and/or thermal deformation is suppressed, the solid polymer electrolyte membrane 12 is joined to the anode 14 and the cathode 16. Thus, it is possible to easily join the anode 14, the solid polymer electrolyte membrane 12, and the cathode 16 together in a desired positional relationship, and suppress deformation of the solid polymer electrolyte membrane 12.
(47) As described above, in this production method, it is possible to easily suppress positional deviation between the anode 14, the solid polymer electrolyte membrane 12, and the cathode 16, and also easily suppress deformation of the solid polymer electrolyte membrane 12, and thus the MEA 10 having excellent quality can be obtained.
(48) Further, in the production method according to the first embodiment of the present invention, the joint body 60 is transferred from the suction/heating surface 26a to the transportation plate 50a of the transportation unit 32. After the joint body 60 has been transferred from the suction/heating surface 26a to the transportation plate 50a, the cathode 16 is transported to the suction/heating surface 26a by the transportation plate 50b. That is, the production apparatus 20 according to the first embodiment of the present invention includes the transportation plate 50a and the transportation plate 50b. The joint body 60 is transferred from the suction/heating surface 26a to the transportation plate 50a. After the joint body 60 has been transferred from the suction/heating surface 26a to the transportation plate 50a, the transportation plate 50b transports the cathode 16 to the suction/heating surface 26a.
(49) In the structure, the suction/heating plate 26 can be used to attract the anode 14 by suction, attract the solid polymer electrolyte membrane 12 by suction through the anode 14, attract the cathode 16 by suction, and attract the solid polymer electrolyte membrane 12 (joint body 60) by suction though the cathode 16. Consequently, it becomes possible to simplify the structure of the production apparatus 20.
(50) Next, a production apparatus 70 according to a second embodiment will be described with reference to
(51) As shown in
(52) For example, the third suction unit 72 has the same structure as the first suction unit 22. That is, it is possible for the third suction unit 72 to attract the cathode 16 to the main surface 30a by suction through a plurality of through holes 74 formed in the heating plate 30.
(53) Next, a production method according to the second embodiment using the production apparatus 70 will be described. In the production method according to the second embodiment, as shown in
(54) In this manner, after the joint body 60 is formed on the suction/heating surface 26a, as shown in
(55) Next, as shown in
(56) Next, as shown in
(57) Next, the heating plate 30 with the cathode 16 being attracted by suction thereto is moved closer to the joint body 60 attracted to the suction/heating surface 26a by suction. In this manner, as shown in
(58) In a state where the temperature of the heating plate 30 is raised by the second heating unit 28, by moving the heating plate 30 much closer to the suction/heating surface 26a, it is possible to press and heat the stack body 10a, and join the cathode 16 to the other surface 12b of the solid polymer electrolyte membrane 12 (second joining step). As a result, it is possible to obtain the MEA 10 formed by joining the anode 14 and the cathode 16 to respective both sides of the solid polymer electrolyte membrane 12.
(59) That is, in the production method according to the second embodiment, in the same manner as in the case of the production method according to the first embodiment, it is possible to easily suppress positional deviation between the anode 14, the solid polymer electrolyte membrane 12, and the cathode 16, and also easily suppress deformation of the solid polymer electrolyte membrane 12, and thus the MEA 10 having excellent quality can be obtained.
(60) Further, in the production method according to the second embodiment, by providing the third suction unit 72 on the heating plate 30, it is possible to stack the cathode 16 on the joint body 60 formed on the suction/heating surface 26a, using the heating plate 30, to thereby form the stack body 10a. Further, since the solid polymer electrolyte membrane 12 and the cathode 16 can be joined together by moving the heating plate 30 closer to the suction/heating surface 26a directly, it is possible to improve the efficiency of producing the MEA 10.
(61) The present invention is not limited to the above described embodiments. It is a matter of course that various structures may be adopted without departing from the scope of the present invention.
(62) For example, in the production method according to the first embodiment and the second embodiment, in the first joining step, the anode 14 as the first electrode is joined to one surface 12a of the solid polymer electrolyte membrane 12. Further, in the second joining step, the cathode 16 as the second electrode is joined to the other surface 12a of the solid polymer electrolyte membrane 12.
(63) However, in the first joining step, instead of the anode 14, the cathode 16 as the first electrode may be joined to one surface 12a of the solid polymer electrolyte membrane 12. Further, in the second joining step, instead of the cathode 16, the anode 14 as the second electrode may be joined to the other surface 12b of the solid polymer electrolyte membrane 12.