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 .
Election/Restrictions
Applicant’s election without traverse of Species 2A in the reply filed on 06/08/2026 is acknowledged.
Claims 1-6, 12-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected Species 1A-1B, Species 2A, and Species 3A-3B, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 06/08/2026.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim 7 is rejected under 35 U.S.C. 102(a)(1) as being anticipated by Waki et al. (JP 2007165025 A).
Regarding claim 7, Waki discloses a fuel cell ([2]) comprising: a gas diffusion layer (GDL) ([9];[12];[66], Fig. 5, 5) situated between a catalyst layer (i.e. in contact with electrode catalyst layer, [13];[9], Fig. 5, 2) and a flow field plate of the fuel cell (i.e. separator, [99]).
Waki further discloses the gas diffusion layer comprises a water repellent layer and a gas diffusion base ([12]) where the water repellent layer is divided into a hydrophobic portion (Fig. 5, 6) and a hydrophilic portion (Fig. 5, 7) ([66]). Furthermore, Waki discloses that in the water repellent layer, there is a concentration gradient of a material having thermal conductivity from the electrode catalyst layer to the gas diffusion base material and the concentration of the material having thermal conductivity decreases towards the gas diffusion material ([67]). One of ordinary skill would recognize that in possessing a concentration gradient of a material having thermal conductivity from the electrode catalyst side to the gas diffusion base material side, the water repellent layer, as well as the GDL, possess a gradient of thermal conductivity.
Thus, Waki satisfies the claim limitation, “the GDL having a gradient of thermal conductivity between a first region of the GDL and a second region of the GDL along a thickness direction of the fuel cell, the first region being adjacent to the catalyst layer having a higher thermal conductivity, the second region being adjacent to the flow field plate having a lower thermal conductivity than the higher thermal conductivity” as shown in annotated Waki Fig. 5 below.
PNG
media_image1.png
426
897
media_image1.png
Greyscale
Annotated Waki Fig. 5
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Waki et al. (JP 2007165025 A), as applied to claim 7 above.
Regarding claim 11, Waki teaches the thermal conductivity of the material to be in the range of 0.2 to 100 W/m∙K, which overlaps with the claimed range of 0.1 to 20 W/m∙K. Waki further teaches if the thermal conductivity of the material is less than 0.2 W/m∙K, the temperature drop in the water repellent layer becomes large and the water vapor tends to condense and flooding is likely to occur ([18]). Conversely, if the thermal conductivity exceeds 100 W/m∙K, the hydrophobicity of the carbon becomes strong making it difficult to draw water from the catalyst layer, thus leading to flooding ([18]).
While Waki does not explicitly disclose a thermal conductivity for the gradient, a skilled artisan would recognize that Waki, in a desire to control the thermal conductivity of the material having thermal conductivity within the water repellent layer, would also have a desire to control the thermal conductivity of the gradient within the water repellent layer and GDL.
Waki further teaches the water repellent layer comprising of the gradient of material having thermal conductivity ([67]) further comprises a water repellent material ([26]) which is preferably polytetrafluoroethylene (PFTE) ([28]). PFTE has a thermal conductivity of 0.25 W/m∙K (see Ebnesajjad et al., pg. 62, Table 3.46).
The water repellent layer within the GDL having a concentration gradient of the material with thermal conductivity of 0.2 to 100 W/m∙K, as well as PFTE with thermal conductivity of 0.25 W/m∙K, would result in a gradient with a thermal conductivity range overlapping with or encompassing the claimed range of 0.2 to 100 W/m∙K.
Thus, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have routinely selected and optimized within the overlapping portion of the ranges for the thermal conductivity of the material having thermal conductivity, as well as the gradient in the GDL, in order to achieve the desired balance between the temperature drop in the water repellent layer and the hydrophobicity of carbon in order to prevent flooding, as taught by Waki.
Claims 7-10 is rejected under 35 U.S.C. 103 as being unpatentable over Quayle et al. (US 20080268297 A1) in view of Waki et al. (JP 2007165025 A).
Regarding claim 7, Quayle discloses a fuel cell ([0002]) comprising: a gas diffusion layer (GDL) (i.e. gas diffusion electrode, [0004]) situated adjacent to a catalyst layer of the fuel cell (i.e. gas diffusion substrate adjacent to electrocatalyst layer, [0032]).
While Quayle does not explicitly disclose the gas diffusion layer adjacent to a flow field plate such that it is situated between a catalyst layer and flow field plate, a skilled artisan would recognize that Quayle’s fuel cell requires a flow field plate.
Nevertheless, Waki teaches a similar membrane electrode assembly ([2]) and further teaches that generally the electrode, specifically the membrane electrode assembly including the gas diffusion layer, is sandwiched between flow field plates (i.e. separators, [99]), and is adjacent to a catalyst layer ([11]). Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to have situated the GDL between a catalyst layer of the fuel cell and a flow field plate of the fuel cell, with reasonable expectation of success in achieving a satisfactory fuel cell as this is a well-known configuration in the art for fuel cells.
Quayle further teaches the GDL comprises a gradient of concentration of graphitic particles and hydrophobic particles across the thickness of the fibre network, wherein there is a higher concentration of graphitic particles and hydrophobic particles at the face adjacent to the electrocatalyst layer ([0032]). Quayle further discloses the amount of graphitic particles and hydrophobic polymer at a first face (i.e. adjacent to the electrocatalyst layer) is at least 2 times, and preferably at least 4 times, the amount of graphitic particles and hydrophobic polymer at a second face ([0017]) (i.e. adjacent to the flow field plate). Quayle further discloses the graphitic particles may be flake graphite or spherical graphite, and the hydrophobic polymer is preferably PTFE, all of which a skilled artisan would recognize necessarily and inherently possess respective thermal conductivities (see Ding et al., Table 4.7 and Ebnesajjad et al., pg. 62, Table 3.46 ).
Therefore, in possessing a gradient of concentration of graphitic particles and hydrophobic polymer across the thickness of the GDL such that the highest concentration of particles is at the face adjacent to the electrocatalyst layer and the lowest concentration is adjacent to the fuel flow plate, modified Quayle satisfies the claim limitation, “the GDL having a first region and a second region along a thickness direction of the fuel cell, the first region being adjacent to the catalyst layer and having a higher thermal conductivity, the second region being adjacent to the flow field plate and having a lower thermal conductivity”.
Regarding claim 8-10, modified Quayle discloses all limitations as set forth above.
Modified Quayle discloses the GDL comprises a non-woven network of carbon fibres (Quayle, [0009]), as well as a gradient of graphitic particles and hydrophobic polymer across the thickness of the fibre network (Quayle, [0017]).
Modified Quayle further discloses the graphitic particles may be graphitized carbon blacks, but are suitably flake graphite or spherical graphite (Quayle, [0015]), thus rendering obvious the selection of flake or spherical graphite as the first material with reasonable expectation that such a selection would lead to a successful GDL.
As spherical graphite, the first material, has a thermal conductivity of 80 W/m∙K (see Ding et al., Table 4.7) and carbon fiber, the second material, has a thermal conductivity of 2.2-7 W/m∙K (see Biron et al., Table 3.19), modified Quayle satisfies the claim limitations, “wherein the GDL includes a mixture of a first material and a second material, the first material having a first thermal conductivity, the second material having a second thermal conductivity lower than the first thermal conductivity” of claim 8, “the first material includes graphite” of claim 9, and “the second material includes carbon fibers” of claim 10.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Wang et al. (JP 20098116 A) discloses a gas diffusion layer with a thermal conductivity gradient in the length direction.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ESTHER J TAN whose telephone number is (571)272-3479. The examiner can normally be reached M-F 7:30 AM-4:30PM.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jonathan Leong can be reached at (571)270-1292. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/E.J.T./Examiner, Art Unit 1751
/Haroon S. Sheikh/Primary Examiner, Art Unit 1751
Prosecution Insights