Prosecution Insights
Last updated: April 19, 2026
Application No. 17/816,256

SYSTEMS AND METHODS FOR CIRCULATING ELECTROLYTE AND ELECTRIC CURRENT IN SERIES COUPLED REDOX FLOW BATTERY CELLS

Non-Final OA §102§103
Filed
Jul 29, 2022
Examiner
GODO, OLATUNJI A
Art Unit
1752
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Ess Tech Inc.
OA Round
1 (Non-Final)
86%
Grant Probability
Favorable
1-2
OA Rounds
2y 5m
To Grant
95%
With Interview

Examiner Intelligence

Grants 86% — above average
86%
Career Allow Rate
950 granted / 1106 resolved
+20.9% vs TC avg
Moderate +9% lift
Without
With
+9.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 5m
Avg Prosecution
30 currently pending
Career history
1136
Total Applications
across all art units

Statute-Specific Performance

§101
0.5%
-39.5% vs TC avg
§103
45.7%
+5.7% vs TC avg
§102
32.1%
-7.9% vs TC avg
§112
16.4%
-23.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1106 resolved cases

Office Action

§102 §103
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 . Allowable Subject Matter Claims 6, 13-16, 20 are allowable over the prior art of record. 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. 1. Claims 1-3, 7-12 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Vanderzaden (US20190190400). 2. Regarding claim 1, Vanderzaden teaches a redox flow battery system comprising: a plurality of redox flow battery cells electrically coupled in series, such that each of the plurality of redox flow battery cells is directly electrically coupled to at least one adjacent redox flow battery cell (In one example, electric energy storage device 105 may be comprised of a plurality of battery cells 106. In another example, electric energy storage device may be an all iron redox flow battery as is shown in FIG. 6. Battery cells 106 may be arranged in a series electrical connection scheme to increase voltage of electric energy storage device 105 [0017]), wherein each of the plurality of redox flow battery cells (Referring now to FIG. 6, an example embodiment of an all iron redox flow battery (IFB) is shown [0060]) comprises positive and negative electrode compartments respectively housing redox and plating electrodes (The IFB includes a negative electrode 614 and a positive electrode 616 [0060]; positive reactor 624 and negative reactor 622 of the IFB [0060]). 3. Regarding claim 2, Vanderzaden teaches further comprising a plurality of electrolyte storage tanks, wherein each of the plurality of electrolyte storage tanks is fluidically coupled to the positive and negative electrode compartments of a respective one of the plurality of redox flow battery cells (The IFB may include plating electrolyte that is stored in plating electrolyte tank 600. The IFB may also include redox electrolyte that is stored in redox electrolyte tank 601…Both tanks may be in fluidic communication with the positive reactor 624 and negative reactor 622 of the IFB. Separating the negative and positive reactors and their respective electrolytes is barrier 620 [0060]). 4. Regarding claim 3, Vanderzaden teaches wherein each of the plurality of electrolyte storage tanks is prismatic in shape (electrolyte tanks 600 and 601 [0060]; see Figure 6). 5. Regarding claim 7, Vanderzaden teaches wherein the redox flow battery system is an all-iron hybrid redox flow battery system (Referring now to FIG. 6, an example embodiment of an all iron redox flow battery (IFB) is shown [0060]). 6. Regarding claim 8, Vanderzaden teaches a system (FIG. 2 is a schematic diagram of an electric power conversion system that utilizes a sole DC/DC converter [0010]), comprising: an electrolyte subsystem (The IFB may include plating electrolyte that is stored in plating electrolyte tank 600. The IFB may also include redox electrolyte that is stored in redox electrolyte tank 601 [0060]); a redox flow battery cell (Referring now to FIG. 6, an example embodiment of an all-iron redox flow battery (IFB) is shown. The IFB is an electric energy storage device that may be included in the system of FIG. 2 as element 20 [0060]) fluidically coupled to the electrolyte subsystem (The IFB may include plating electrolyte that is stored in plating electrolyte tank 600. The IFB may also include redox electrolyte that is stored in redox electrolyte tank 601… Both tanks may be in fluidic communication with the positive reactor 624 and negative reactor 622 of the IFB [0060]); a power inverter directly electrically coupled to the redox flow battery cell (Thus, electric energy storage device 205 solely supplies electric power to stationary AC electric power grid 114 via inverter 112 [0035]; Referring now to FIG. 6, an example embodiment of an all iron redox flow battery (IFB) is shown. The IFB is an electric energy storage device that may be included in the system of FIG. 2 as element 205 [0060]); and an electrical grid directly electrically coupled to the power inverter (Inverter 112 is electrically coupled to stationary AC electric power grid 114 [0022]; Figure 2). 7. Regarding claim 9, Vanderzaden teaches wherein the redox flow battery cell operates in a first voltage range of 40 to 75 V (As such, battery voltage (e.g., 48 volts) [0030]), and wherein the power inverter operates in a second voltage range of 600 to 1000 V (In one example, voltage of DC buss 203 is controlled to a voltage that may provide 300-1000 VDC when switched to match inverter 112 input [0023]). 8. Regarding claim 10, Vanderzaden teaches wherein the redox flow battery cell is electrically coupled to at least one additional redox flow battery cell in series (Battery cells 106 may be arranged in a series electrical connection scheme to increase voltage of electric energy storage device 105 [0017]). 9. Regarding claim 11, Vanderzaden teaches wherein the electrolyte subsystem comprises an electrolyte storage tank (Referring now to FIG. 6, an example embodiment of an all-iron redox flow battery (IFB) is shown [0060]; The IFB may include plating electrolyte that is stored in plating electrolyte tank 600. The IFB may also include redox electrolyte that is stored in redox electrolyte tank 601…Both tanks may be in fluidic communication with the positive reactor 624 and negative reactor 622 of the IFB. Separating the negative and positive reactors and their respective electrolytes is barrier 620 [0060]), and wherein the system further comprises a closed electrolyte flow path passing through the electrolyte storage tank and the redox flow battery cell (see Figure 6). 10. Regarding claim 12, Vanderzaden teaches wherein the closed electrolyte flow path comprises a positive electrolyte flow loop and a negative electrolyte flow loop (see Figure 6). 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 of this title, 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. 11. Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Vanderzaden (US20190190400) as applied to claim 1 in view of Jaramillo et al. (US20200136153) 12. Regarding claim 4, Jaramillo teaches wherein each of the plurality of redox flow battery cells is fluidically isolated from each other of the plurality of redox flow battery cells (As examples, pumps, valves, and other partitions of the primary battery units 110 may be used to fluidically isolate portions of the primary battery units 110 to enable the electrolyte levels in the primary battery units 110 to be raised and/or lowered to facilitate collection and removal of spent fuel [0052]) for the benefit of providing a refuelable battery to provide a sustainable, cost-effective, and/or operationally efficient solution [0019]. 13. It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified Vanderzaden with Jaramillo’s teachings for the benefit of providing a refuelable battery to provide a sustainable, cost-effective, and/or operationally efficient solution. 14. Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Vanderzaden (US20190190400) as applied to claim 1 in view of Aarskog (US 20200328446) 15. Regarding claim 5, Aarskog teaches wherein no electrical path electrically coupling any one of the plurality of redox flow battery cells to a DC-to-DC boost converter is present in the redox flow battery system (A plurality of electrical switches (two electrical switches 191, 192 in the embodiment of FIG. 3) is provided between the flow battery module 101 and the electrical power converter 190. The electrical switches 191, 192 permit to electrically isolate the flow battery module 101 from the electrical power converter 190 [0091]) in case an electrical failure occurs in the flow battery module 101 or in the electrical power converter 190 [0091]. 16. It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified Vanderzaden with Aarskog’s teachings in case an electrical failure occurs in the flow battery module or in the electrical power converter. 17. Claims 17-19 are rejected under 35 U.S.C. 103 as being unpatentable over Vanderzaden (US20190190400) in view of Jaramillo et al. (US20200136153) 18. Regarding claims 17 and 19, Vanderzaden teaches a method for a redox flow battery system, the method comprising: coupling a plurality of redox flow battery cells in series (In one example, electric energy storage device 105 may be comprised of a plurality of battery cells 106. In another example, electric energy storage device may be an all iron redox flow battery as is shown in FIG. 6. Battery cells 106 may be arranged in a series electrical connection scheme to increase voltage of electric energy storage device 105 [0017]); circulating an electrolyte across each of the plurality of series coupled redox flow battery cells of the redox flow battery system ((Referring now to FIG. 6, an example embodiment of an all-iron redox flow battery (IFB) is shown [0060]; The IFB may include plating electrolyte that is stored in plating electrolyte tank 600. The IFB may also include redox electrolyte that is stored in redox electrolyte tank 601…Both tanks may be in fluidic communication with the positive reactor 624 and negative reactor 622 of the IFB. Separating the negative and positive reactors and their respective electrolytes is barrier 620 [0060]); and while the electrolyte is circulating across each of the plurality of series coupled redox flow battery cells (FIG. 6 shows a schematic diagram of an example electric energy storage device that may be included in the electric power conversion system of FIG. 2 [0014]), circulating a first electric current across the plurality of series coupled redox flow battery cells and a power inverter (charge from electric energy storage device 105 may be supplied to stationary AC electrical power grid 114 via DC bus 108, second DC/DC converter 110, and inverter 112 [0017]). 19. Vanderzaden is silent each of the plurality of series coupled redox flow battery cells is fluidically isolated from each other of the plurality of series coupled redox flow battery cells. 20. Jaramillo teaches wherein each of the plurality of redox flow battery cells is fluidically isolated from each other of the plurality of series coupled redox flow battery cells (As examples, pumps, valves, and other partitions of the primary battery units 110 may be used to fluidically isolate portions of the primary battery units 110 to enable the electrolyte levels in the primary battery units 110 to be raised and/or lowered to facilitate collection and removal of spent fuel [0052]) for the benefit of providing a refuelable battery to provide a sustainable, cost-effective, and/or operationally efficient solution [0019]. 21. It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified Vanderzaden with Jaramillo’s teachings for the benefit of providing a refuelable battery to provide a sustainable, cost-effective, and/or operationally efficient solution. 22. Regarding claim 18, Vanderzaden teaches further comprising reversibly flowing the first electric current between the power inverter and an electrical grid (Electric power output from second DC/DC converter 110 is converted to AC electri6c power via inverter 112. Inverter 112 transfers AC electric power to stationary AC electrical power grid 114. [0018]). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to OLATUNJI GODO whose telephone number is (571)272-3104. The examiner can normally be reached 8:00 am - 5:30 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, Nicholas Smith can be reached on 571-272-8760. 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. /OLATUNJI A GODO/Primary Examiner, Art Unit 1752
Read full office action

Prosecution Timeline

Jul 29, 2022
Application Filed
Nov 15, 2025
Non-Final Rejection — §102, §103 (current)

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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
86%
Grant Probability
95%
With Interview (+9.1%)
2y 5m
Median Time to Grant
Low
PTA Risk
Based on 1106 resolved cases by this examiner. Grant probability derived from career allow rate.

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