DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Priority
Acknowledgment is made of applicant's claim for foreign priority based on an application filed in Japan on 9 Apr 2020. It is noted, however, that applicant has not filed a certified copy of the JP2020-070590 application as required by 37 CFR 1.55.
Response to Arguments
Applicant’s arguments, filed 13 Jan 2026, have been fully considered but are not considered persuasive. Regarding claim 1, Applicant argues that the limitations of the amended claim, which now recites “an integrated pore volume for all the pores having the diameter of 3 nm or more and 5.5 um or less in the fuel electrode side-electrocatalyst layer and the oxygen electrode-side electrocatalyst layers,” are not taught by the prior art. The Examiner respectfully disagrees, and submits that this limitation is taught by the prior art reference of Green et al. (US 2009/0208751), as set forth below.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim(s) 1-4 and 9-13 are rejected under 35 U.S.C. 103 as being unpatentable over Kawai et al. (US 2007/0015041) in view of Green et al. (US 2009/0208751).
As to claim 1, Kawai et al. discloses a membrane electrode assembly (see e.g. membrane-electrode assembly, [0014]) for use in a polymer electrolyte fuel cell, comprising:
a polyelectrolyte membrane (see e.g. ion exchange resin membrane, [0014]) having a first surface and a second surface facing away from the first surface (see e.g. ion exchange membrane has a first surface facing an anode catalyst layer and an opposing second surface facing a cathode catalyst layer, [0014]);
a fuel electrode-side electrocatalyst layer (see e.g. anode catalyst layer, [0014], [0025]) bonded to the first surface and containing a first catalytic material (see e.g. the anode catalyst layer, comprises an anode catalyst platinum which reads on the first catalytic material, [0025]-[0026]), a first electrically conductive carrier supporting the first catalytic material (see e.g. carbon support, which supports the catalyst and may be the conductive material carbon black, [0026]-[0027]), and a first polyelectrolyte (see e.g. ion-conductive polymer electrolyte, which is in the electrode paste, see [0024], [0030]-[0031]); and
an oxygen electrode-side electrocatalyst layer (see e.g. cathode catalyst layer, [0014], [0025]) bonded to the second surface and containing a second catalytic material (see e.g. the cathode catalyst layer, comprises a cathode catalyst platinum which reads on the second catalytic material, [0025]-[0026]), a second electrically conductive carrier supporting the second catalytic material (see e.g. carbon support, which supports the catalyst and may be the conductive material carbon black, [0026]-[0027]), a second polyelectrolyte (see e.g. ion-conductive polymer electrolyte, which is in the electrode paste, see [0024], [0030]-[0031]), and a fibrous material (see e.g. carbon fibers, [0081]), and
the fuel electrode-side electrocatalyst layer and the oxygen electrode-side electrocatalyst layer contain voids which include pores (see e.g. [0101]).
Kawai et al. is silent as to the diameter of these pores, and does not explicitly disclose pores having a diameter of 3 nm or more and 5.5 mm or less.
Additionally, Kawai et al. discloses an overall integrated pore volume of 0.1 to 3.0 cm3/g for all pores (see e.g. [0101]), but Kawai et al. is silent as to the integrated pore volume for all the pores having the diameter of 3 nm or more and 5.5 mm.
Green et al., also working in the field of catalyst materials for fuel cells, teaches a catalyst carrier comprising pores having a pore diameter of 100 nm or less (see e.g. Green et al.: [0088] and [0071], giving a maximum pore size of about 100 nm), which lies within and thereby anticipates the claimed range of 3 nm or more and 5.5 mm or less. Green et al. obviates an integrated pore volume of 3.0 to about 5.0 cm3/g for pores that have a diameter of 3 nm or more or 5.5 mm or less (see e.g. Green et al.: [0025] - because the maximum pore diameter is 100 nm or less, the total pore volume is substantially the same as the pore volume for pores that have a diameter of 3 nm or more or 5.5 mm or less), which substantially overlaps and thereby renders obvious the claimed range of 2.8 to 4.5 cm3/g. Green et al. further teaches that this catalyst carrier is suitable for use as a catalyst support for a fuel cell (see e.g. Green et al.: [0088]).
It would therefore have been obvious to one of ordinary skill in the art prior to the filing date of the claimed invention to modify the membrane assembly of Kawai et al. by substituting Green et al.’s catalyst carrier for Kawai et al.’s catalyst carrier, resulting in catalyst layers containing voids which include pores having a diameter of 3 nm or more and 5.5 mm or less and wherein an integrated pore volume for all the pores having the diameter of 3 nm or more and 5.5 mm or less in the fuel electrode side-electrocatalyst layer and the oxygen electrode-side electrocatalyst layers is a first integrated volume, a value obtained by dividing the first integrated volume by a mass of a catalytic material, that is a mass of the catalytic material contained in both of the electrocatalyst layers, is in a range of 2.8 cm3/g or more and 4.5 cm3/g or less. Said artisan would have been motivated to make such a substitution because Green et al. teaches that this catalyst carrier is appropriate for use in a fuel cell. Greene et al teach these mesoporous carbon black particles are highly desirable for fuel cell applications in that they allow mass transfer across the entire surface area of the particles, thereby enabling both the deposition of the platinum or platinum alloy catalyst particles and the transfer of ions and species for efficient fuel cell operation (paragraph [0095]).
As to claim 2, Kawai et al. in view of Green et al. teaches the membrane electrode assembly of claim 1.
Kawai et al. in view of Green et al. does not teach a membrane assembly wherein when an integrated pore volume for the pores having a pore size of 50 nm or less is a second integrated volume, a percentage of the second integrated volume to the first integrated volume is in a range of 25% or more and 45% or less in at least one of the fuel electrode-side electrocatalyst layer and the oxygen electrode-side electrocatalyst layer.
However, as described in MPEP 2112 III, a rejection under 35 USC §103 can be made when the prior art product seems to be identical except that the prior art is silent as to an inherent characteristic. In this case, Kawai et al. discloses pores having a structure that lies within the scope of the instantly-claimed pores, as set forth above.
Kawai et al. in view of Green et al. further discloses that the pore structure of the catalyst layer affects performance of the fuel cell by facilitating the transport of water (see e.g. Kawai et al.: [0101]), which is similar to the goal pursued by applicant in forming the claimed porous structure including the claimed integrated pore volume per mass range (see Instant Specification, [0007], [0010]). Thus, the catalyst layers of Kawai et al. in view of Green et al. are compositionally similar to that of applicant’s invention, as claimed, and further appear to be configured to achieve the same, or substantially the same, function in terms of smooth supply of gases in order to enhance power generation.
One of ordinary skill in the art would therefore have reasonably expected that the pores in the electrocatalyst layers of Kawai et al. in view of Green et al. would have a second integrated pore volume for the pores having a pore size of 50 nm or less, such that a percentage of the second integrated volume to the first integrated volume is in the claimed range of 25% or more and 45% or less in either of the electrocatalyst layers, as similar structure is present and similar functional results are achieved.
Further, Green et al. teach that the pore size and distribution materially effects the properties of the catalyst layer in fuel cell applications (paragraph [0095-99]), and therefore establishes that the that pores size and distribution is a result effective variable that should be optimized (per MPEP 2144.05 Part II).
As to claim 3, Kawai et al. in view of Green et al. teaches the membrane electrode assembly of claim 1.
Kawai et al. in view of Green et al. does not teach a membrane assembly wherein when an integrated pore volume for the pores having a pore size of 90 nm or more is a third integrated volume, a percentage of the third integrated volume to the first integrated volume is in a range of 15% or more and 35% or less in at least one of the fuel electrode-side electrocatalyst layer and the oxygen electrode-side electrocatalyst layer.
However, as described in MPEP 2112 III, a rejection under 35 USC §103 can be made when the prior art product seems to be identical except that the prior art is silent as to an inherent characteristic. In this case, Kawai et al. discloses pores having a structure that lies within the scope of the instantly-claimed pores, as set forth above.
Kawai et al. in view of Green et al. further discloses that the pore structure of the catalyst layer affects performance of the fuel cell by facilitating the transport of water (see e.g. Kawai et al.: [0101]), which is similar to the goal pursued by applicant in forming the claimed porous structure including the claimed integrated pore volume per mass range (see Instant Specification, [0007], [0010]). Thus, the catalyst layers of Kawai et al. in view of Green et al. are compositionally similar to that of applicant’s invention, as claimed, and further appear to be configured to achieve the same, or substantially the same, function in terms of smooth supply of gases in order to enhance power generation.
One of ordinary skill in the art would therefore have reasonably expected that the pores in the electrocatalyst layers of Kawai et al. in view of Green et al. would have an integrated pore volume for the pores having a pore size of 90 nm or more is a third integrated volume, a percentage of the third integrated volume to the first integrated volume is in a range of 15% or more and 35% or less in at least one of the fuel electrode-side electrocatalyst layer and the oxygen electrode-side electrocatalyst layer, as similar structure is present and similar functional results are achieved.
Further, Green et al. teach that the pore size and distribution materially effects the properties of the catalyst layer, and therefore establishes that the that pores size and distribution is a result effective variable that should be optimized (per MPEP 2144.05 Part II).
As to claim 4, Kawai et al. in view of Green et al. teaches the membrane electrode assembly of claim 1.
Kawai et al. in view of Green et al.’s pore size distribution has a peak of a distribution curve indicating the pore volume plotted against the pore size at approximately 0.05 mm (see e.g. Green et al.: Fig. 5B), which is close enough to the claimed range of 0.06 mm or more and 0.11 mm as to render the claimed range obvious to one of ordinary skill in the art.
As to claim 9, Kawai et al. in view of Green et al. teaches the membrane electrode assembly of claim 1.
Kawai et al. in view of Green et al. does not teach a membrane assembly wherein when an integrated pore volume for the pores having a pore size of 50 nm or less is a second integrated volume, a percentage of the second integrated volume to the first integrated volume is in a range of 25% or more and 55% or less in at least one of the fuel electrode-side electrocatalyst layer and the oxygen electrode-side electrocatalyst layer.
However, as described in MPEP 2112 III, a rejection under 35 USC §103 can be made when the prior art product seems to be identical except that the prior art is silent as to an inherent characteristic. In this case, Kawai et al. in view of Green et al. discloses pores having a structure that lies within the scope of the instantly-claimed pores, as set forth above.
Kawai et al. in view of Green et al. further discloses that the pore structure of the catalyst layer affects performance of the fuel cell by facilitating the transport of water (see e.g. Kawai et al.: [0101]), which is similar to the goal pursued by applicant in forming the claimed porous structure including the claimed integrated pore volume per mass range (see Instant Specification, [0007], [0010]). Thus, the catalyst layers of Kawai et al. in view of Green et al. are compositionally similar to that of applicant’s invention, as claimed, and further appear to be configured to achieve the same, or substantially the same, function in terms of smooth supply of gases in order to enhance power generation.
One of ordinary skill in the art would therefore have reasonably expected that the pores in the electrocatalyst layers of Kawai et al. would have a second integrated pore volume for the pores having a pore size of 50 nm or less, such that a percentage of the second integrated volume to the first integrated volume is in the claimed range of 25% or more and 55% or less in either of the electrocatalyst layers, as similar structure is present and similar functional results are achieved.
As to claim 10, Kawai et al. in view of Green et al. teaches the membrane electrode assembly of claim 1.
Kawai et al. in view of Green et al. does not teach a membrane assembly wherein when an integrated pore volume for the pores having a pore size of 90 nm or more is a third integrated volume, a percentage of the third integrated volume to the first integrated volume is in a range of 10% or more and 35% or less in at least one of the fuel electrode-side electrocatalyst layer and the oxygen electrode-side electrocatalyst layer.
However, as described in MPEP 2112 III, a rejection under 35 USC §103 can be made when the prior art product seems to be identical except that the prior art is silent as to an inherent characteristic. In this case, Kawai et al. in view of Green et al. discloses pores having a structure that lies within the scope of the instantly-claimed pores, as set forth above.
Kawai et al. in view of Green et al. further discloses that the pore structure of the catalyst layer affects performance of the fuel cell by facilitating the transport of water (see e.g. Kawai et al.: [0101]), which is similar to the goal pursued by applicant in forming the claimed porous structure including the claimed integrated pore volume per mass range (Instant Specification, [0007], [0010]). Thus, the catalyst layers of Kawai et al. in view of Green et al. are compositionally similar to that of applicant’s invention, as claimed, and further appear to be configured to achieve the same, or substantially the same, function in terms of smooth supply of gases in order to enhance power generation.
One of ordinary skill in the art would therefore have reasonably expected that the pores in the electrocatalyst layers of Kawai et al. in view of Green et al. would have a third integrated pore volume for the pores having a pore size of 90 nm or less, such that a percentage of the third integrated volume to the first integrated volume is in a range of 10% or more and 35% or less in at least one of the fuel electrode-side electrocatalyst layer and the oxygen electrode-side electrocatalyst layer.
As to claim 11, Kawai et al. in view of Green et al. teaches a polymer electrolyte fuel cell (see e.g. fuel cell sample, Kawai et al.: [0127]) that comprises a membrane electrode assembly that meets all of the limitations of claim 1, as set forth in the rejection of claim 1 above.
As to claim 12, Kawai et al. in view of Green et al. teaches the membrane electrode assembly of claim 1, wherein the value obtained by dividing the first integrated volume by the mass of the catalytic material contained in both of the electrocatalyst layers, is in a range of 3.21 cm3/g or more and 4.5 cm3/g or less (see e.g. Green et al.: [0025], teaching a total integrated pore volume of 3.0 cm3/g to 5.0 cm3/g, which overlaps and thereby renders obvious the claimed range of 3.21 cm3/g or more and 4.5 cm3/g or less).
As to claim 13, Kawai et al. in view of Green et al. teaches the membrane electrode assembly of claim 1, wherein the value obtained by dividing the first integrated volume by the mass of the catalytic material contained in both of the electrocatalyst layers, is in a range of 3.33 cm3/g or more and 4.5 cm3/g or less (see e.g. Green et al.: [0025], teaching a total integrated pore volume of 3.0 cm3/g to 5.0 cm3/g, which overlaps and thereby renders obvious the claimed range of 3.33 cm3/g or more and 4.5 cm3/g or less).
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Kawai et al. (US 2007/0015041) in view of Green et al. (US 2009/0208751) as applied to claim 1 above, and further in view of Tokuda et al. (US 2010/0323265).
As to claim 5, Kawai et al. in view of Green et al. teaches the membrane electrode assembly of claim 1, wherein the fibrous material contains carbon nanofibers (see e.g. carbon fibers, Kawai et al.: [0015], [0081]), but does not teach fibers selected from electron- conducting fibers and proton-conducting fibers.
Tokuda et al., also working in the field of membrane assemblies for fuel cells, teaches the use of conductive carbon nanofibers as a support for a catalyst in a fuel cell catalyst layer (see e.g. Tokuda et al.: [0046]).
It would therefore have been obvious to one of ordinary skill in the art prior to the filing date of the claimed invention to use the conductive carbon nanofibers taught by Tokuda et al. as a support for a catalyst layer instead of the generic carbon fibers disclosed by Kawai et al. in view of Green et al., because conductive carbon nanofibers were a known catalyst support material used for the same intended purpose and such a substitution would yield only readily predictable effects.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Kawai et al. (US 2007/0015041) in view of Green et al. (US 2009/0208751) as applied to claim 1 above, and further in view of Hong et al. (US 2014/0170525).
As to claim 6, Kawai et al. in view of Green et al. teaches the membrane electrode assembly of claim 1, wherein the fuel electrode-side electrocatalyst layer (see e.g. anode catalyst layer, Kawai et al.: [0009]) further contains a fibrous material (see e.g. carbon fibers, which are included in the electrode paste that makes up the anode layer, Kawai et al.: [0025], [0081]); and when the fibrous material contained in the fuel electrode-side electrocatalyst layer is a first fibrous material (i.e., carbon fiber), and the fibrous material contained in the oxygen electrode-side electrocatalyst layer is a second fibrous material (see e.g. carbon fibers, which are included in the electrode paste that makes up the cathode layer, Kawai et al.: [0025], [0081]).
Kawai et al. in view of Green et al. is silent as to the mass of the first fibrous material per unit volume and the mass of the second fibrous material per unit volume, and does not teach a mass of the first fibrous material per unit volume of the fuel electrode-side electrocatalyst layer is larger than a mass of the second fibrous material per unit volume of the oxygen electrode-side electrocatalyst layer.
Hong et al., also working in the field of membrane electrode assembly design for fuel cells, teaches that it is advantageous for the fuel electrode-side catalyst layer (i.e., the anode layer) to have a greater pore volume than the oxygen electrode-side layer (cathode layer), because doing so improves the durability of the anode by improving acid retention (see e.g. Hong et al.: [0037], [0046]). Further, Kawai et al. teaches that the fibrous material have an effect of increasing the pore volume of the catalyst layer (see e.g. Kawai et al.: [0082]),
It would therefore have been obvious to one of ordinary skill in the art prior to the filing date of the claimed invention to set the mass of the first and second fibrous materials in the fuel and oxygen electrode catalyst layers of Kawai et al. in view of Green et al. such that a mass of the first fibrous material per unit volume of the fuel electrode-side electrocatalyst layer is larger than a mass of the second fibrous material per unit volume of the oxygen electrode-side electrocatalyst layer. Said artisan would have been motivated to adjust the amounts of first and second fibrous materials in this way in order to make the pore volume of the fuel electrode-side catalyst layer greater than that of the oxygen electrode-side catalyst layer in order to improve the durability of the membrane assembly, as taught by Hong et al..
Claims 7-8 are rejected under 35 U.S.C. 103 as being unpatentable over Kawai et al. (US 2007/0015041) in view of Green et al. (US 2009/0208751) as applied to claim 1 above, and further in view of Kofuji (JP 2020132965, as read via machine translation).
As to claim 7, Kawai et al. in view of Green et al. teaches the membrane electrode assembly of claim 1.
Kawai et al. in view of Green et al. is silent as to the thickness of the oxygen electrode-side electrocatalyst layer and does not teach a membrane electrode assembly wherein the oxygen electrode-side electrocatalyst layer has a thickness in a range of 5 mm or more and 30 mm or less.
Kofuji, also working on the problem of materials for fuel cells, teaches a similar membrane electrode assembly comprising an oxygen electrode-side electrocatalyst layer (see e.g. catalyst layer in anode section, Kofuji: [0030], Fig. 3). Kofuji further teaches that it is preferable for the oxygen electrode-side electrocatalyst layer (see e.g. catalyst layer, Kofuji: [0030]) of a fuel cell to have a thickness in the range of 5 mm to 100 mm in order to balance the diffusion distance of the carbon dioxide gas and thereby improve the efficiency of the catalyst (see e.g. Kofuji: [0027], [0035], and Fig. 1). Kofuji further teaches that the thickness of the oxygen electrode-side electrocatalyst layer must not be too thick or too thin in order to prevent non-uniformity in the diffusion layer and minimize the cost of the components (see e.g. Kofuji: [0024]). The thickness range taught by Kofuji overlaps and thereby renders obvious the instantly-claimed range of 5 mm to 30 mm.
It would therefore have been obvious to one of ordinary skill in the art prior to the filing date of the instantly-claimed invention to produce the oxygen electrode-side electrocatalyst layer in the membrane electrode assembly of Kawai et al. in view of Green et al. with a thickness of 5 mm to 30 mm. Said artisan would have been motivated to select such a thickness in order to improve the efficiency of the fuel cell, as taught by Kofuji.
As to claim 8, Kawai et al. in view of Green et al. teaches the membrane electrode assembly of claim 1, including a fuel-side electrocatalyst layer (see e.g. anode layer, Kawai et al. [0009]).
Kawai et al. in view of Green et al. is silent as to the thickness of the fuel-side electrocatalyst layer.
Kofuji, also working on the problem of materials for fuel cells, teaches a similar membrane electrode assembly comprising an oxygen electrode-side electrocatalyst layer (see e.g. catalyst layer in anode section, Kofuji: [0030], Fig. 3). Kofuji further teaches that it is preferable for the oxygen electrode-side electrocatalyst layer (see e.g. catalyst layer, Kofuji: [0030]) of a fuel cell to have a thickness in the range of 5 mm to 100 mm in order to balance the diffusion distance of the carbon dioxide gas and thereby improve the efficiency of the catalyst (see e.g. Kofuji: [0027], [0035], and Fig. 1). Kofuji further teaches that the thickness of the oxygen electrode-side electrocatalyst layer must not be too thick or too thin in order to prevent non-uniformity in the diffusion layer and minimize the cost of the components (see e.g. Kofuji: [0024]). The thickness range taught by Kofuji overlaps and thereby renders obvious the instantly-claimed range of 5 mm to 20 mm.
It would therefore have been obvious to one of ordinary skill in the art prior to the filing date of the instantly-claimed invention to produce the oxygen electrode-side electrocatalyst layer in the membrane electrode assembly of Kawai et al. in view of Green et al. with a thickness of 5 mm to 20 mm. Said artisan would have been motivated to select such a thickness in order to improve the efficiency of the fuel cell, as taught by Kofuji.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/A.M.H./Examiner, Art Unit 1723
/NICHOLAS P D'ANIELLO/Primary Examiner, Art Unit 1723
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