Prosecution Insights
Last updated: October 04, 2026
Application No. 18/412,269

NEGATIVE ELECTRODE SPACER FOR FLOW BATTERY

Non-Final OA §102
Filed
Jan 12, 2024
Priority
Feb 03, 2023 — provisional 63/483,203
Examiner
BARCENA, CARLOS
Art Unit
Tech Center
Assignee
ESS Tech Inc.
OA Round
1 (Non-Final)
80%
Grant Probability
Favorable
1-2
OA Rounds
0m
Est. Remaining
93%
With Interview

Examiner Intelligence

Grants 80% — above average
80%
Career Allowance Rate
916 granted / 1138 resolved
+20.5% vs TC avg
Moderate +12% lift
Without
With
+12.3%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
37 currently pending
Career history
1153
Total Applications
across all art units

Statute-Specific Performance

§101
1.0%
-39.0% vs TC avg
§103
46.3%
+6.3% vs TC avg
§102
26.3%
-13.7% vs TC avg
§112
20.6%
-19.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1138 resolved cases

Office Action

§102
DETAILED ACTION Claim Rejections - 35 USC § 102 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. Claims 1, 4, 5, 7, 8, 15 and 17-19 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Bian et al. (WO 2017/171289), machine translation. Regarding claims 1 and 7, Bian discloses a bipolar plate and redox flow cell comprising: bipolar plates 118 and 119 including a plate-shaped body 152 (Fig. 6a); and partition wall 154 (negative electrode spacer comprising an array of discrete structures protruding from the surface of the bipolar plate). Various other shapes are also envisaged (Fig. 7). Figures 6A and 7 to Bian are provided below. PNG media_image1.png 460 678 media_image1.png Greyscale PNG media_image2.png 876 806 media_image2.png Greyscale Regarding claims 4 and 5, Bian discloses wherein the array of discrete structures is spaced apart from one another along a first axis and a second axis of the bipolar plate, the first axis parallel with a direction of predominant electrolyte flow across the bipolar plate and the second axis perpendicular to the first axis, and wherein the array of discrete structures is not mechanically coupled to one another (Fig. 6A). Regarding claim 8, Bian discloses wherein the array of discrete structures extends between the surface of the bipolar plate and a membrane separator of the electrode assembly, and wherein the membrane separator is maintained a uniform distance away from the surface of the bipolar plate by the array of discrete structures (Fig. 4). Regarding claims 15 and 17-19, Bian discloses raised portions interpreted as a square peg (Fig. 7h). Claims 1, 3-5, 7, and 8 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Markiewicz et al. (US 2018/0205067). Regarding claims 1 and 7, Markiewicz discloses additive manufactured electrode for flow battery comprising: bipolar plate 150 and may include electrode 10 (para 0091); and negative electrode spacer comprising an array of discrete structures protruding from the surface of the bipolar plate (Figs. 5A-8B). Exemplary example 6B is provided below. PNG media_image3.png 772 646 media_image3.png Greyscale Regarding claim 3, Markiewicz discloses additive manufacturing techniques (para 0014). Regarding claims 4 and 5, Markiewicz discloses wherein the array of discrete structures is spaced apart from one another along a first axis and a second axis of the bipolar plate, the first axis parallel with a direction of predominant electrolyte flow across the bipolar plate and the second axis perpendicular to the first axis, and wherein the array of discrete structures is not mechanically coupled to one another (Figs. 5A-8B). Regarding claim 8, Markiewicz discloses wherein the array of discrete structures extends between the surface of the bipolar plate and a membrane separator of the electrode assembly, and wherein the membrane separator is maintained a uniform distance away from the surface of the bipolar plate by the array of discrete structures (Fig. 12B). Allowable Subject Matter Claims 9-14 are allowed. Claims 2, 6, 16, and 20 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to CARLOS BARCENA whose telephone number is (571)270-5780. The examiner can normally be reached Monday-Thursday 8-5 pm. 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, Tong Guo can be reached at (571)272-3066. 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. /CARLOS BARCENA/Primary Examiner, Art Unit 1723
Read full office action

Prosecution Timeline

Jan 12, 2024
Application Filed
Sep 01, 2026
Non-Final Rejection mailed — §102 (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

1-2
Expected OA Rounds
80%
Grant Probability
93%
With Interview (+12.3%)
2y 9m (~0m remaining)
Median Time to Grant
Low
PTA Risk
Based on 1138 resolved cases by this examiner. Grant probability derived from career allowance rate.

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