Prosecution Insights
Last updated: April 19, 2026
Application No. 18/301,927

METHODS AND SYSTEM FOR REDOX FLOW BATTERY IDLE STATE

Non-Final OA §102§103
Filed
Apr 17, 2023
Examiner
HANSEN, JARED A
Art Unit
1723
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Ess Tech Inc.
OA Round
1 (Non-Final)
54%
Grant Probability
Moderate
1-2
OA Rounds
3y 11m
To Grant
99%
With Interview

Examiner Intelligence

Grants 54% of resolved cases
54%
Career Allow Rate
55 granted / 101 resolved
-10.5% vs TC avg
Strong +45% interview lift
Without
With
+45.1%
Interview Lift
resolved cases with interview
Typical timeline
3y 11m
Avg Prosecution
47 currently pending
Career history
148
Total Applications
across all art units

Statute-Specific Performance

§101
1.4%
-38.6% vs TC avg
§103
54.6%
+14.6% vs TC avg
§102
18.0%
-22.0% vs TC avg
§112
17.8%
-22.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 101 resolved cases

Office Action

§102 §103
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 . 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. (a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention. Claim(s) 1, 10-14 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by US20180316031A1 (cited in IDS filed 17 April 2023; hereafter referred to as Song-031). Regarding claim 1, Song-031 discloses a method of operating a redox flow battery system (Song-031, [0077]), responsive to switching the redox flow battery system to an idle mode, wherein the idle mode includes operation of the redox flow battery system outside of a charging mode and outside of a discharging mode (Song-031, [0077]), initiating an off cycle timer (Song-031. [0063], “in response to the redox flow battery system being in idle mode, the controller 88 begins cycling of the electrolyte pumps, including deactivating the electrolyte pump and initiating a first timer”) monitoring an off cycle threshold period of time (Song-031, [0064], “the controller 88 may determine if the first timer is greater than a first threshold duration), activating an electrolyte pump in response to elapsing of the off cycle threshold period of time to circulate electrolytes through one or more electrode compartments (Song-031, [0066], “If the first timer is greater than the first threshold duration, then the method proceeds from 410 to 414 to send a control signal to the actuator of the electrolyte pump to activate the electrolyte pump at an idle threshold flow rate”, Song-031, [0029], “Electrolytes are stored in one or more tanks external to the cell, and are pumped via pumps 30 and 32 through the negative electrode compartment 20 side and the positive electrode compartment 22 side of the battery, respectively.”) Regarding claim 10, Song-031 discloses a method for a redox flow battery system (Song-031, [0077]), comprising: responsive to operation of the redox flow battery system in an idle mode, cycling an electrolyte pump between an off interval and an on interval, the off interval having a duration corresponding to an off threshold period of time and the on interval having a duration corresponding to an on threshold period of time (Song-031, [0064], “The first threshold duration may be based on target amount of time between successive activation (cycling ON) of the electrolyte pump during redox flow battery idle mode…the first threshold duration may correspond to a pump OFF interval during idle mode…a pump ON interval corresponding to a second threshold duration.”), wherein electrolytes are circulated through one or more electrode compartments during the on interval (Song-031, [0029], “Electrolytes are stored in one or more tanks external to the cell, and are pumped via pumps 30 and 32 through the negative electrode compartment 20 side and the positive electrode compartment 22 side of the battery, respectively.”, [0064], “a pump ON interval corresponding to a second threshold duration.”). Regarding claim 11, Song-031 further discloses wherein the off threshold period of time is longer than the on threshold period of time (Song-031, [0064]). Regarding claim 12, Song-031 also discloses wherein the off threshold period of time is adjusted based on a power module voltage of the redox flow battery system, and wherein the off threshold period of time is increased when the power module voltage is increased and decreased when the power module voltage is decreased (Song-031, [0065]). Regarding claim 13, Song-031 additionally discloses wherein the electrolytes are circulated through the one or more electrode compartments during the on interval at an idle threshold flow rate, and wherein the idle threshold flow rate is lower than a charge or discharge threshold flow rate (Song-031, [0077]). Regarding claim 14, Song-031 further discloses wherein the duration of the off threshold period of time is decreased when anticipated power demands are increased and the duration of the off threshold period of time is increased when the anticipated power demands are decreased (Song-031, [0070]). 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. 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(s) 2-3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Song US20180316031A1 (cited in IDS filed 17 April 2023, hereafter referred to as Song-031), as applied to claims 1 and 10 above, in view of Keshavarz US20110086247A1. Regarding claim 2, Song-031 discloses all of the claim limitations as set forth above and further discloses wherein initiate an off cycle timer (Song-031. [0063], “in response to the redox flow battery system being in idle mode, the controller 88 begins cycling of the electrolyte pumps, including deactivating the electrolyte pump and initiating a first timer”) and an on cycle timer is initiated after the off cycle threshold period of time elapses (Song-031, [0066], “A second timer is initiated in conjunction with the activation of the electrolyte pump, the second timer measuring a pump ON duration during the idle pump cycling”), and wherein the on cycle timer measures an on cycle threshold period of time for circulating the electrolytes (Song-031, [0029], “Electrolytes are stored in one or more tanks external to the cell, and are pumped via pumps 30 and 32 through the negative electrode compartment 20 side and the positive electrode compartment 22 side of the battery, respectively.”, [0064], “a pump ON interval corresponding to a second threshold duration.”). Song-031 further discloses wherein the electrolyte is replaced (Song-031, [0025]), electrolytes in redox flow battery cells may be replenished and refreshed sufficiently to increase a power module voltage, while reducing parasitic power and shunting losses in the idle mode (Song-031, [0074]) and the controller determines electrolyte pumps’ statuses and pump timers (Song-031, [0059]), which pumps, statuses and times are used to determine if the electrolyte is sufficiently refreshed (Song-031, [0074]), which the skilled artisan would understand to disclose a means of draining and it would be obvious to the skilled artisan to modify the method of Song-031 wherein initiate a drain timer and a period of time monitored by the drain timer while the redox flow battery system is still in the idle mode thereby electrolytes in redox flow battery cells may be replenished and refreshed sufficiently to increase a power module voltage, while reducing parasitic power and shunting losses in the idle mode. Song-031 however does not disclose wherein a drain timer is initiated concurrent with the off cycle timer and the drain timer monitors a drain threshold period of time. In a redox flow battery system Keshavarz teaches a power module comprising a plurality of redox flow battery cell stacks, each of the plurality of redox flow battery cell stacks comprising a redox flow battery cell (Keshavarz, [0033], “multiple redox flow cells 100 can be electrically coupled (e.g., stacked) either in series to achieve higher voltage or in parallel in order to achieve higher current”), an electrolyte pump capable of delivering electrolyte from an electrolyte tank to the power module (Keshavarz, [0034], “pumping system is used to transport the electrolytes to and from the redox flow cell”), one or more electrode compartments (Keshavarz, [0034], “half-cell 110 of redox flow cell 100 contains anolyte 126 and the other half-cell 108 contains catholyte 124, the anolyte and catholyte being collectively referred to as electrolytes”), a power control system with a controller storing executable instructions in non-transitory memory (Keshavarz, [0097], “control system 500 includes a controller 510. Controller 510 includes one or more processors, volatile and non-volatile memory to store data and programming”). Keshavarz also teaches in order to rebalance the parity between the active components of the electrolytes (Keshavarz, [0054]) the controller beings a state to cycle through fill and drain electrode electrolyte compartment states to prepare for performing rebalance reactions (Keshavarz, [0101]), including opening and closing a drain valve based on an elapsed time, monitoring a drain threshold period of time (Keshavarz, [0103]) in order to effectively removes or recycles parasitic side products produced during the charge/discharge cycles of a flow cell battery to rebalance the charge states between the two electrolytic solutions (Keshavarz, [0007]). Therefore it would be obvious to the skilled artisan before the effective filing date of the claimed invention to modify the system of modified Song-031 with the teaching of Keshavarz wherein initiate a drain timer and the drain timer monitors a drain threshold period of time thereby effectively removing or recycling parasitic side products produced during the charge/discharge cycles of a flow cell battery to rebalance the charge states between the two electrolytic solutions. It would further be obvious to one of ordinary skill in the art to modify the instructions of modified Song-031 wherein initiate an off cycle timer and a drain timer concurrently in order to deactivate the pump(s) and drain the electrode electrolyte compartments. Regarding claim 3, modified Song-031 also teaches wherein drain valve 342 may remain open for some period of time after electrolyte begins to fill electrode electrolyte compartment 240 in order to flush electrode electrolyte compartment 240 (Keshavarz, [0087]), satisfying the claim limitation wherein the drain threshold period of time is longer than the off cycle threshold period of time. Claim(s) 4-9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Song US20180316031A1 (cited in IDS filed 17 April 2023, hereafter referred to as Song-031) in view of Keshavarz US20110086247A1, as applied to claims 2 above, in view of Song US20180316032A1 (cited in IDS file 17 April 2023; hereafter referred to as Song-032). Regarding claim 4, modified Song-031 additionally teaches wherein the electrolyte is replaced (Song-031, [0025]), electrolytes in redox flow battery cells may be replenished and refreshed sufficiently to increase a power module voltage, while reducing parasitic power and shunting losses in the idle mode (Song-031, [0074]) and the controller determines electrolyte pumps’ statuses and pump timers (Song-031, [0059]), which pumps, statuses and times are used to determine if the electrolyte is sufficiently refreshed (Song-031, [0074]), and in order to rebalance the parity between the active components of the electrolytes (Keshavarz, [0054]) the controller beings a state to cycle through fill and drain electrode electrolyte compartment states to prepare for performing rebalance reactions (Keshavarz, [0101]), including opening and closing a drain valve based on an elapsed time elapsing a threshold (Keshavarz, [0103]) in order to effectively removes or recycles parasitic side products produced during the charge/discharge cycles of a flow cell battery to rebalance the charge states between the two electrolytic solutions (Keshavarz, [0007]). satisfying the claim limitation, completely drain the electrolyte from the one or more electrode compartments of the redox flow battery system and refilling the one or more electrode compartments with fresh electrolytes. Modified Song-031 however does not teach purging the one or more electrode compartments with a gas, and refilling the one or more electrode compartments with fresh electrolytes when the drain threshold period of time elapses. In a redox flow battery system Song-032 teaches comprising a power module (Song-032, [0030]) comprising a plurality of redox flow battery cell stacks, each of the plurality of redox flow battery cell stacks comprising a redox flow battery cell (Song-032, [0035]), an electrolyte pump (Song-032, [0026]) capable of delivering electrolyte from an electrolyte tank to the power module (Song-032, [0026]), and a power control system with a controller storing executable instructions in non-transitory memory (Song-032, [0057]), the instructions executable to completely drain the electrolyte from the one or more electrode compartments of the redox flow battery system (Song-032, [0041-0042]), purge the drained one or more electrode compartments with a gas (Song-032, [0041-0042]) and refill the purged and drained one or more electrode compartments with fresh electrolyte (Song-032, [0041-0042]) in order to achieve performance step-increases (e.g., higher charging and discharging rates) (Song-032, [0041]). Therefore it would be obvious to the skilled artisan to modify the method of modified Song-031 with the teaching of Song-032 wherein completely draining electrolytes from one or more electrode compartments of the redox flow battery system, purging the one or more electrode compartments with a gas, and refilling the one or more electrode compartments with fresh electrolytes when the drain threshold period of time elapses thereby achieving performance step-increases (e.g., higher charging and discharging rates). Regarding claim 5, modified Song-031 further teaches wherein a vacuum is generated in the one or more electrode compartments when the one or more electrode compartments are drained, and wherein the vacuum draws the gas into the one or more electrode compartments to purge the one or more electrode compartments Song-032, [0041], “operating a redox flow battery with a positive cross-over pressure, whereby a pressure in the positive electrode compartment is maintained greater than a pressure in the negative electrode compartment, can aid in purging gas from a microporous membrane layer 234 of a redox flow battery cell separator 230, thereby reducing a resistivity of the redox flow battery cell”). Regarding claim 6, modified Song-031 teaches all of the claim limitations as set forth above including wherein a drain timer is initiated concurrent with the off cycle timer (see claim 2 above). Song-031 additionally teaches wherein the off cycle threshold period of time corresponds to deactivating the electrolyte pump (Song-031, [0063]) and further comprising completely draining electrolytes from one or more electrode compartments of the redox flow battery system, purging the one or more electrode compartments with a gas (see claim 4 above) in order to account for performance step-increases (e.g., higher charging and discharging rates) (Song-032, [0041]). Therefore while Song-031 is not explicitly directed toward the priority of the draining and pumping, it would be obvious to one of ordinary skill in the art to modify the method of modified Song-031 wherein when elapsing of the off cycle threshold period of time is concurrent with elapsing of the drain threshold period of time, the draining of the electrolytes from the one or more electrode compartments is prioritized over activation of the electrolyte pump thereby accounting for performance step-increases (e.g., higher charging and discharging rates). Regarding claim 7, modified Song-031 additionally teaches wherein in response to maintaining the redox flow battery system in the idle mode, the electrolyte pump is repeatedly cycled between the active and inactive states (Song-031, [0069]) and the various redox flow battery system parameters, including time thresholds, may be adjusted according to the anticipated power demands during a battery idle mode (Song-031, [0070]) in order that idle mode operation parameters may be adjusted by the controller depending on the anticipated power needs to maintain a redox flow battery system responsiveness while reducing parasitic and shunting losses (Song-031, [0070]). Therefore it would be obvious to one of ordinary skill in the art to modify the method of modified Song-031 wherein further comprising, in response to maintaining the redox flow battery system in the idle mode after the drain threshold period of time has elapsed and the one or more electrode compartments are refilled with the fresh electrolytes, initiating the off cycle timer again thereby idle mode operation parameters may be adjusted by the controller depending on the anticipated power needs to maintain a redox flow battery system responsiveness while reducing parasitic and shunting losses. Regarding claim 8, modified Song-031 also teaches wherein the electrolytes are drained from the one or more electrode compartments by opening a drain valve of the one or more electrode compartments (Keshavarz, [0087]; Song-032, [0041-0042]). Regarding claim 9, modified Song-031 further teaches wherein the electrolyte drained from the electrode electrolyte compartment, and filled with an inert gas such as argon (Ar), purging gas from the microporous membrane layer (Song-032, [0041]) in order to reduce a resistivity of the redox flow battery cell (Song-032, [0041]), which would be obvious to one of ordinary skill in the art wherein the drain valve is closed when the one or more electrode compartments are purged with the gas, and wherein the gas is argon thereby reducing a resistivity of the redox flow battery cell, since if the drain valve were not closed, the compartment could not be filled/flushed with the argon gas. Claim(s) 15-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Song US20180316031A1 (cited in IDS filed 17 April 2023, hereafter referred to as Song-031), as applied to claim 10 above, in view of Keshavarz US20110086247A1 and further in view of Song US20180316032A1 (cited in IDS file 17 April 2023; hereafter referred to as Song-032). Regarding claim 15, Song-031 discloses all of the claim limitations as set forth above and further discloses initiation of an off threshold period of time (Song-031. [0063], “in response to the redox flow battery system being in idle mode, the controller 88 begins cycling of the electrolyte pumps, including deactivating the electrolyte pump and initiating a first timer”), wherein the electrolyte is replaced (Song-031, [0025]), electrolytes in redox flow battery cells may be replenished and refreshed sufficiently to increase a power module voltage, while reducing parasitic power and shunting losses in the idle mode (Song-031, [0074]) and the controller determines electrolyte pumps’ statuses and pump timers (Song-031, [0059]), which pumps, statuses and times are used to determine if the electrolyte is sufficiently refreshed (Song-031, [0074]), which the skilled artisan would understand to disclose a means of draining and it would be obvious to the skilled artisan to modify the method of Song-031 wherein initiate a drain timer and a period of time monitored by the drain timer while the redox flow battery system is still in the idle mode thereby electrolytes in redox flow battery cells may be replenished and refreshed sufficiently to increase a power module voltage, while reducing parasitic power and shunting losses in the idle mode. Song-031 however does not explicitly disclose further comprising monitoring a drain threshold period of time, the drain threshold period of time initiated concurrently with initiation of the off threshold period of time, and wherein when the drain threshold period of time elapses, the one or more electrode compartments are drained, purged, and refilled. In a redox flow battery system Keshavarz teaches a power module comprising a plurality of redox flow battery cell stacks, each of the plurality of redox flow battery cell stacks comprising a redox flow battery cell (Keshavarz, [0033], “multiple redox flow cells 100 can be electrically coupled (e.g., stacked) either in series to achieve higher voltage or in parallel in order to achieve higher current”), an electrolyte pump capable of delivering electrolyte from an electrolyte tank to the power module (Keshavarz, [0034], “pumping system is used to transport the electrolytes to and from the redox flow cell”), one or more electrode compartments (Keshavarz, [0034], “half-cell 110 of redox flow cell 100 contains anolyte 126 and the other half-cell 108 contains catholyte 124, the anolyte and catholyte being collectively referred to as electrolytes”), a power control system with a controller storing executable instructions in non-transitory memory (Keshavarz, [0097], “control system 500 includes a controller 510. Controller 510 includes one or more processors, volatile and non-volatile memory to store data and programming”). Keshavarz also teaches in order to rebalance the parity between the active components of the electrolytes (Keshavarz, [0054]) the controller beings a state to cycle through fill and drain electrode electrolyte compartment states to prepare for performing rebalance reactions (Keshavarz, [0101]), including opening and closing a drain valve based on an elapsed time, monitoring a drain threshold period of time (Keshavarz, [0103]) in order to effectively removes or recycles parasitic side products produced during the charge/discharge cycles of a flow cell battery to rebalance the charge states between the two electrolytic solutions (Keshavarz, [0007]). Therefore it would be obvious to the skilled artisan before the effective filing date of the claimed invention to modify the system of modified Song-031 with the teaching of Keshavarz wherein initiate a drain threshold period of time thereby effectively removing or recycling parasitic side products produced during the charge/discharge cycles of a flow cell battery to rebalance the charge states between the two electrolytic solutions. It would further be obvious to one of ordinary skill in the art to modify the instructions of modified Song-031 wherein the drain threshold period of time initiated concurrently with initiation of the off threshold period of time in order to deactivate the pump(s) and drain the electrode electrolyte compartments. Modified Song-031 additionally teaches wherein the controller begins a state to cycle through fill and drain electrode electrolyte compartment states to prepare for performing rebalance reactions (Keshavarz, [0101]), including opening and closing a drain valve based on an elapsed time elapsing a threshold (Keshavarz, [0103]) in order to effectively removes or recycles parasitic side products produced during the charge/discharge cycles of a flow cell battery to rebalance the charge states between the two electrolytic solutions (Keshavarz, [0007]). satisfying the claim limitation, wherein when the drain threshold period of time elapses, the one or more electrode compartments are drained and refilled. Modified Song-031 however is silent as to one or more electrode compartments are purged. In a redox flow battery system Song-032 teaches comprising a power module (Song-032, [0030]) comprising a plurality of redox flow battery cell stacks, each of the plurality of redox flow battery cell stacks comprising a redox flow battery cell (Song-032, [0035]), an electrolyte pump (Song-032, [0026]) capable of delivering electrolyte from an electrolyte tank to the power module (Song-032, [0026]), and a power control system with a controller storing executable instructions in non-transitory memory (Song-032, [0057]), the instructions executable to completely drain the electrolyte from the one or more electrode compartments of the redox flow battery system (Song-032, [0041-0042]), purge the drained one or more electrode compartments with a gas (Song-032, [0041-0042]) and refill the purged and drained one or more electrode compartments with fresh electrolyte (Song-032, [0041-0042]) in order to achieve performance step-increases (e.g., higher charging and discharging rates) (Song-032, [0041]). Therefore it would be obvious to the skilled artisan to modify the method of modified Song-031 with the teaching of Song-032 wherein when the drain threshold period of time elapses, the one or more electrode compartments are drained, purged, and refilled thereby achieving performance step-increases (e.g., higher charging and discharging rates). Regarding claim 16, modified Song-031 also teaches wherein drain valve 342 may remain open for some period of time after electrolyte begins to fill electrode electrolyte compartment 240 in order to flush electrode electrolyte compartment 240 (Keshavarz, [0087]), satisfying the claim limitation wherein the drain threshold period of time is longer than the off threshold period of time. Regarding claim 17, modified Song-031 teaches all of the claim limitations as set forth above including wherein drain valve 342 may remain open for some period of time after electrolyte begins to fill electrode electrolyte compartment 240 in order to flush electrode electrolyte compartment 240 (Keshavarz, [0087]), the off cycle threshold period of time corresponding to the electrolyte pump being activated in the idle mode, the on cycle threshold period of time corresponding to the electrolyte pump being deactivated in the idle mode. Therefore it would be obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the instructions of modified Song-031 wherein the drain threshold period of time is longer than the off threshold period of time and the on threshold period of time combined thereby completely draining the electrode electrolyte compartments. Regarding claim 18, modified Song-031 teaches when the electrolyte has not been refreshed/rebalanced that a pH of the electrolytes in the one or more electrode compartments rises and causes iron to be reduced and formation of iron hydroxide (Song-031, [0039]; Keshavarz, [0053-0054]) and that in order to rebalance the parity between the active components of the electrolytes (Keshavarz, [0054]) the controller beings a state to cycle through fill and drain electrode electrolyte compartment states to prepare for performing rebalance reactions (Keshavarz, [0101]), including opening and closing a drain valve based on an elapsed time, monitoring a drain threshold period of time (Keshavarz, [0103]) in order to effectively removes or recycles parasitic side products produced during the charge/discharge cycles of a flow cell battery to rebalance the charge states between the two electrolytic solutions (Keshavarz, [0007]). Therefore it would be obvious to the skilled artisan to modify the method of modified Song-031 wherein the drain threshold period of time is a duration of time before a pH of the electrolytes in the one or more electrode compartments rises and causes formation of iron hydroxide thereby rebalancing the parity between the active components of the electrolytes and rebalancing the charge states between the two electrolytic solutions. Regarding claim 19, modified Somg-031 teaches all of the claim limitations as set forth above including wherein accumulation of reduced iron, including in the form of iron hydroxide, reduces battery performance (Song-031, [0039]; Keshavarz, [0053-0054]) and wherein opening and closing a drain valve based on an elapsed time, monitoring a drain threshold period of time (Keshavarz, [0103]) in order to effectively removes or recycles parasitic side products produced during the charge/discharge cycles of a flow cell battery to rebalance the charge states between the two electrolytic solutions (Keshavarz, [0007]). Therefore it would be obvious to one of ordinary skill in the art to modify the method of modified Song-031 wherein the drain threshold period of time is a duration of time where a likelihood of reduced battery performance is increased due to accumulation of iron hydroxide thereby rebalancing the parity between the active components of the electrolytes and rebalancing the charge states between the two electrolytic solutions. Regarding claim 20, modified Song-031 also teaches wherein the one or more electrode compartments are refilled with the electrolytes from an electrolyte storage tank or at least one rebalancing reactor (Song-031, [0034-0035]). Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Chang US20130084506A1 (discloses a method for a redox flow battery system comprising pumps, cells, a controller, timers and instructions to execute), Kumamoto US20170098849A1 (discloses a method for a redox flow battery system comprising pumps, drains, cells, a controller, timers and instructions to execute), Song US20180316036A1 (discloses a method for a redox flow battery system comprising cells, pumps, tanks, drains, a controller, timers, instructions to execute, placing the system in an idle mode). Any inquiry concerning this communication or earlier communications from the examiner should be directed to JARED HANSEN whose telephone number is (571)272-4590. The examiner can normally be reached M-F. 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, Tiffany Legette can be reached at 571-270-7078. 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. /JARED HANSEN/Examiner, Art Unit 1723 /TIFFANY LEGETTE/Supervisory Patent Examiner, Art Unit 1723
Read full office action

Prosecution Timeline

Apr 17, 2023
Application Filed
Nov 28, 2025
Non-Final Rejection — §102, §103 (current)

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Prosecution Projections

1-2
Expected OA Rounds
54%
Grant Probability
99%
With Interview (+45.1%)
3y 11m
Median Time to Grant
Low
PTA Risk
Based on 101 resolved cases by this examiner. Grant probability derived from career allow rate.

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