Prosecution Insights
Last updated: April 19, 2026
Application No. 17/572,679

FUEL CELL STACK AND METHOD FOR MANUFACTURE

Non-Final OA §103§112
Filed
Jan 11, 2022
Examiner
WEST, ROBERT GENE
Art Unit
1721
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Plug Power Inc.
OA Round
3 (Non-Final)
77%
Grant Probability
Favorable
3-4
OA Rounds
3y 4m
To Grant
99%
With Interview

Examiner Intelligence

Grants 77% — above average
77%
Career Allow Rate
76 granted / 99 resolved
+11.8% vs TC avg
Strong +25% interview lift
Without
With
+24.9%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
56 currently pending
Career history
155
Total Applications
across all art units

Statute-Specific Performance

§103
55.4%
+15.4% vs TC avg
§102
19.3%
-20.7% vs TC avg
§112
23.8%
-16.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 99 resolved cases

Office Action

§103 §112
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 . If status of the application as subject to 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 a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 9/29/2025 has been entered. Status of Claims Claims 1-21 are pending in the application. Claims 1-13 are withdrawn. Claims 14-21 were rejected in the office action mailed 5/29/2025. Claims 14-21 are presently examined. Response to Amendment / Arguments The amendment filed 9/29/2025, in response to the office action mailed 5/29/2025, has been entered. Applicant’s arguments overcame all 35 U.S.C. 102 & 103 rejections; nevertheless, claim 21 remains rejected under 35 U.S.C. 103 due to additional prior art. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. Claim 21 is rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor(s) regard as the invention. Claim 21 states “the first opening”. There is insufficient antecedent basis for this limitation in this claim. For present examination, “the first opening” means “the opening”. 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: Determining the scope and contents of the prior art. Ascertaining the differences between the prior art and the claims at issue. Resolving the level of ordinary skill in the pertinent art. Considering objective evidence present in the application indicating obviousness or nonobviousness. The claims are in bold font, the prior art is in parentheses. Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over CN110571448A machine translation (Fan) in view of US20140186740A1 (Kwon). Fan teaches the following claim 21 limitations (amended according to Examiner’s interpretation in the 112(b) section above): A method for use in manufacturing a fuel cell system (page 7, lines 29-36; figures 2-3: bipolar plate 400a for a fuel cell) comprising: forming an opening (page 7, lines 35-40; figure 3: hollow portion 401x) in [a] …sheet (page 7, lines 35-40; figure 3: sealing layer 401); locating a first metal separator (page 7, lines 35-40; figure 3: metal plate 405a) on a first side of the sheet (401) covering the opening (401x) in a first sheet portion of the sheet (401); locating a coolant flow layer (page 7, lines 35-40; figure 3: coolant flow material layer 403) in the(401x); locating a second metal separator (page 7, lines 35-40; figure 3: metal plate 405b) on a second side of the sheet (401) covering the opening (401x). Figure A: Annotated, Fan Figure 3 PNG media_image1.png 598 677 media_image1.png Greyscale Fan doesn’t refer to manufacture of the above structure. Fan does, however, teach the opening (page 7, lines 35-40; figure 3: hollow portion 401x), which must have been formed. Fan also illustrates the separate components, as in claim 21. It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, to manufacture Fan’s bipolar plate, as required by the claim 21 method, based on the teachings of Fan. Fan doesn’t teach that the sheet is electrically non-conductive. Kwon teaches a fuel cell stack (paragraphs 16, 60, & 63) with high output voltage (abstract). Kwon’s fuel cell stack has a plurality of openings (paragraph 42; figure 1: openings 25 & 26) in an electrically non-conductive sheet (paragraphs 42 & 44: first and second divided separators 20a and 20b connected in an insulated manner). It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, for Fan’s sealing layer 401 to be insulated / electrically non-conductive, as taught by Kwon, as part of a fuel cell stack with high output voltage. Allowable Subject Matter Withdrawn claims 1-13 could be allowed with claims 14-20 if all structural features of allowed claim 14 are added into claims 1 & 7. Claims 14-20 are allowed. The following is a statement of reasons for allowance: US20140186740A1 (Kwon) in view of CN110571448A machine translation (Fan) and US20150228988A1 (Andreas) are the closest prior art of record for claims 14-20. Kwon teaches the following claim 14 limitations: A method for use in manufacturing a fuel cell system (paragraphs 16, 60, & 63) comprising: forming a plurality of openings (paragraph 42; figure 1: openings 25 & 26) in an electrically non-conductive sheet (paragraphs 42 & 44: first and second divided separators 20a and 20b connected in an insulated manner), the openings linearly spaced on the sheet (Figure B below; figure 1); …a first opening (paragraph 42; figure 1: coolant supply manifold 25) of the plurality of openings in a first sheet portion of the sheet (Figure B below)… …a second opening (paragraph 42; figure 1: hydrogen supply manifold 26) of the plurality of openings in a second sheet portion of the sheet connected to the first sheet portion of the sheet, the first opening and the second opening spaced longitudinally relative to each other along a longitudinal dimension of the sheet (Figure B below)… Figure B: Annotated, partial Kwon figure 1 PNG media_image2.png 372 760 media_image2.png Greyscale Although Kwon teaches the first opening, Kwon fails to teach the following structure associated with the first opening. This structure is taught by Fan: locating a first metal separator (page 7, lines 35-40; figure 3: metal plate 405a) on a first side of the sheet (page 7, lines 35-40; figure 3: sealing layer 401) to cover a first opening (page 7, lines 35-40; figure 3: hollow portion 401x)… locating a coolant flow layer (page 7, lines 35-40; figure 3: coolant flow material layer 403) in the first opening (401x) bounded by interior surfaces of the first sheet portion; locating a second metal separator (page 7, lines 35-40; figure 3: metal plate 405b) on a second side of the sheet (401) covering the first opening (401x) to form a first subassembly (page 7, lines 35-40; page 10, lines 6-16; figure 3: coolant manifold); Fan is directed to fuel cell cooling for temperature uniformity (page 5, lines 30-32). Although Kwon teaches the second opening, Kwon fails to teach the following structure associated with the second opening. This structure is taught by Andreas: locating a membrane (paragraph 59; figure 2: membrane electrode assembly 12) in a second opening… connecting a first gas diffusion layer (paragraph 59; figure 2: gas diffusion layer 36) to the second sheet portion on a first side of the second opening and a second gas diffusion layer (paragraph 59; figure 2: gas diffusion layer 36) located to the second sheet portion on a second side of the second opening, the membrane (12) being located between the first gas diffusion layer (36) and the second gas diffusion layer (36) Andreas is directed to a membrane electrode assembly, for a fuel cell, which is easier to manufacture (abstract; paragraph 15). Fan’s hollow portion 401x and Andreas’ membrane electrode assembly 12 are not the same as Kwon’s coolant supply manifold 25 and hydrogen supply manifold 26, respectively. Thus, it would NOT have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, for Kwon’s coolant supply manifold 25 to have the structure taught by Fan, or for Kwon’s hydrogen supply manifold 26 to have the membrane electrode assembly 12 and gas diffusion layer 36 structure taught by Andreas. Claims 15-20 are allowed due to their dependence on claim 14. Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.” Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ROBERT WEST whose telephone number is 703-756-1363 and email address is Robert.West@uspto.gov. The examiner can normally be reached Monday-Friday 10 am - 7 pm ET. 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, Allison Bourke can be reached at 303-297-4684. 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. /R.G.W./Examiner, Art Unit 1721 /ALLISON BOURKE/Supervisory Patent Examiner, Art Unit 1721
Read full office action

Prosecution Timeline

Jan 11, 2022
Application Filed
Dec 10, 2024
Non-Final Rejection — §103, §112
Feb 26, 2025
Response Filed
May 28, 2025
Final Rejection — §103, §112
Sep 29, 2025
Request for Continued Examination
Oct 02, 2025
Response after Non-Final Action
Dec 23, 2025
Examiner Interview (Telephonic)
Jan 26, 2026
Non-Final Rejection — §103, §112 (current)

Precedent Cases

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
77%
Grant Probability
99%
With Interview (+24.9%)
3y 4m
Median Time to Grant
High
PTA Risk
Based on 99 resolved cases by this examiner. Grant probability derived from career allow rate.

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