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 § 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.
Claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over Min, et. al. (US2019280316A1), in view of Song, et. al. (US20200144641A1), and Song II (US 20180316037 A1; The Office notes that II here indicates the second incidence of the same author – because Evans is also the second author on this application as cited, the numeral is provided for distinction between the two references).
Regarding Claim 1, Min teaches a method of refreshing an asymmetric redox flow battery system comprising: providing a completely discharged or at least partially charged redox flow battery system (“[0074] The stopping of the operation of the flow battery may stop the operation of the flow battery that is being operated through repeating charge and discharge two or more times into a fully discharged state (SOC: 0)”) comprising: at least one rechargeable cell (anode and cathode cells 103, 104) comprising a positive electrolyte (“cathode electrolyte liquid 104a”), a negative electrolyte (“cathode electrolyte liquid 103a”), and a separator (“separator 105”) positioned between the positive electrolyte and the negative electrolyte (Fig. 1), the positive electrolyte in contact with a positive electrode, and the negative electrolyte in contact with a negative electrode (“[0006] A flow battery is configured so as to place cathode and anode electrodes on both sides with a separator as a center”); the positive electrolyte comprising water and a metal precursor and having a volume (“[0056] the electrolyte liquid active material of the flow battery may be any one of vanadium ions, titanium ions, chromium ions, manganese ions, iron . . . [0058] The solvent is not particularly limited as long as it is capable of dissolving the electrolyte liquid active material, and examples thereof may comprise an aqueous sulfuric acid solution, an aqueous hydrochloric acid solution, an aqueous nitric acid solution and a mixed solution thereof” where aqueous teaches a solvent containing water); the negative electrolyte comprising water and the metal precursor and having a volume (see prior; because “the” metal precursor is claimed, this must be the same material, for example an Fe / Fe redox flow battery, and Fe ions are taught as an option within the Markush groups); and preventing a mixed electrolyte from flowing past the negative electrode (see below); mixing the positive electrolyte and the negative electrolyte to form the mixed electrolyte having a concentration of metal precursor between the concentration of the metal precursor in the positive electrolyte and the concentration in the negative electrolyte (“[0009] mixing the anode electrolyte liquid and the cathode electrolyte liquid of the flow battery ; electrically oxidizing or reducing the mixed electrolyte liquid” ; because the metal precursor is the same substance, the concentration must be “between” the two concentrations as the reduction or oxidation reaction occurs); apportioning the mixed electrolyte based on the negative electrolyte volume and the positive electrolyte volume to form a refreshed negative electrolyte and a refreshed positive electrolyte (“[0009] dividing the oxidized or reduced electrolyte liquid into each of the cathode electrolyte liquid storage unit and the anode electrolyte liquid storage unit”). Min at [006, 9, 56, 58, 72 – 84].
Examiner notes the preamble recites an asymmetric redox flow battery system. While “asymmetric,” is not used as a descriptor, an asymmetric redox flow battery configuration is one in which a selective membrane and having separated electrolytes, is utilized to hinder crossover between catholyte and anolyte. See, e.g. Shrestha, et. al., Realization of an Asymmetric Non-Aqueous Redox Flow Battery through Molecular Design to Minimize Active Species Crossover and Decomposition, Chem. Eur. J. 2020, 26, 5369. As such, Min teaches an asymmetric redox flow battery system.
Regarding the term, “the negative electrolyte having a concentration of the metal precursor greater than a concentration of the metal precursor in the positive electrolyte,” Min teaches unbalanced states “an unbalanced state with relatively more ion amounts in the cathode electrolyte liquid,” as well as “in an unbalanced state with relatively more ion amounts in the anode electrolyte liquid,” at least suggesting an unbalanced state wherein the negative electrolyte having a concentration of the metal precursor greater than a concentration of the metal precursor in the positive electrolyte. Min at [0076]. Min teaches this may be within the “fully discharged state,” indicating this step falls within the required order of the method, i.e. taking place after complete or partial discharge but prior to mixing of the electrolyte. Id.
Regarding the term, “resuming a flow of the refreshed negative electrolyte past the negative electrode” Min teaches “[0121] When the flow battery is a vanadium battery, metal ions comprised in the electrolyte liquid are in a state where V4+ and V3+ in a fully discharged state are mixed with each other after the dividing, and therefore, the re-operating of the flow battery may be charging the flow battery first, and then operating through repeating charge and discharge.” While this does not include the Fe as selected, “re-operating,” reads upon “resuming a flow,” and because the flow comprises a flow along the negative electrode (see Fig. 1), this reads upon, “resuming a flow of the refreshed negative electrolyte past the negative electrode.”
Regarding the term, “preventing a mixed electrolyte from flowing past the negative electrode,” this is interpreted as preventing the mixing of the electrolyte prior to the mixing step, which is accomplished by the selective membrane 105 during normal operation. See id at Fig. 1, [0035].
Min additionally teaches “[0011] The present specification has an advantage of recovering battery capacity by regenerating an electrolyte liquid of which performance declines due to a membrane permeation phenomenon and an unintended oxidation/reduction reaction. [0012] The present specification has an advantage of recovering battery capacity even when the degree of ion imbalance of an electrolyte liquid is high.” Min at [0011-12].
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Fig. 1 of the redox flow battery of Min, having liquid storage tanks 101 (anolyte), 102 (catholyte), 108 (mixed electrolyte), and 109 (aqueous acid storage unit), connected to electrodes contained within anode cells 103 and cathode cells 104. As capacity drops, electrolyte is channeled via a three way valve into the mixed electrolyte chamber, where it is reduced or oxidized as needed. This is then divided and returned back to the original storage units upon the recycling of the electrolyte. This lower system 200 is referenced further in Claims 2-3.
While Min provides a suggestion of an unbalanced state prior to the mixing stage, Min does not disclose the specific unbalanced state of “the negative electrolyte having a concentration of the metal precursor greater than a concentration of the metal precursor in the positive electrolyte,” despite presenting the unbalanced state in the correct order of steps.
One of ordinary skill would find it obvious to modify the method of Min, such that the unbalanced step prior to the mixing of the electrolyte liquid comprises the negative electrolyte having a concentration of the metal precursor greater than a concentration of the metal precursor in the positive electrolyte, because Min teaches its process has an advantage of recovering battery capacity even when the degree of ion balance of an electrolyte liquid is high, and because one of ordinary skill would not anticipate new or unexpected results by specifying a higher precursor concentration in the negative electrolyte. See MPEP 2144.065 IV(C).
However, modified Min is silent as to preventing a mixed electrolyte from flowing past the negative electrode by isolating the negative electrode from the mixed electrolyte.
Song teaches an all-iron flow battery, having a negative electrolyte (“[0018] FeCl2, FeCl3, FeSO4, Fe2(SO4)3 and the like”) within the plating side (e.g., negative reactor 122), referred to as a plating electrolyte, and a positive electrolyte on the redox side (e.g. positive reactor 124) referred to as the redox electrolyte. Song at [0018 – 20]. Further, Song teaches “both the plating electrolyte and redox electrolyte may use the same salt at different molar concentrations, a feature of the IFB not available in batteries with different reactive compounds.” Id. In addition, Song teaches “[0022] During normal operation (e.g., not during a cleansing cycle), first three-way valve 170 prevents flow of plating electrolyte through bypass passage 180 and permits flow of plating electrolyte from negative reactor 122 to pump 131 as indicated by arrow 177. Similarly, during normal operation, second three-way valve 171 prevents flow of redox electrolyte through bypass passage 181 and permits flow of redox electrolyte from positive reactor 124 to pump 130 as indicated by arrow 178. Thus, plating electrolyte is separated and isolated from redox electrolyte. [0023] During a cleansing cycle, it may be desirable to mix plating electrolyte with redox electrolyte. The mixing may be accomplished via positioning first three-way valve 170 and second three-way valve 171 to second positions. While operating in their second positions, first valve 170 permits plating electrolyte to flow through bypass passage 180 as indicated by arrow 172 and prevents plating electrolyte from flowing from negative reactor 122 to pump 131 . Similarly, while in a second position, second valve 171 permits plating electrolyte to flow through bypass passage 181 as indicated by arrow 173 and prevents plating electrolyte from flowing from positive reactor 124 to pump 130. Valves 170 and 171 may be adjusted between first and second positions via controller 150.” Id. at [0022]. This reads upon “isolating the negative electrode from the mixed electrolyte,” because the mixed electrolyte is not generated until a later “cleansing” step, and a valve isolates the negative electrode. Song also teaches the measurement of SOC via a control system and sensors. Song at [0020-22]. Finally, Song teaches “[0007] The present description may provide several advantages. In particular, the approach may improve SOC estimates for an oxidation-reduction flow battery. Further, the approach may be useful to improve control of an oxidation-reduction flow battery. In addition, the approach may be useful to determine when it may be desirable to perform an oxidation-reduction flow battery cleansing procedure to improve battery cell efficiency.” Id. at [0007]. This teaches or at least suggests a benefit to preventing cleansing or mixing of the electrolyte via isolation (accomplished by the valve apparatus) until the SOC estimate indicates mixing the electrolytes would be beneficial.
However, Song does not directly disclose “mixing the positive electrolyte and the negative electrolyte to form the mixed electrolyte having a concentration of metal precursor between the concentration of the metal precursor in the positive electrolyte and the concentration in the negative electrolyte; apportioning the mixed electrolyte based on the negative electrolyte volume and the positive electrolyte volume to form a refreshed negative electrolyte and a refreshed positive electrolyte; and resuming a flow of the refreshed negative electrolyte past the negative electrode.”
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Fig. 1 of Song.
One of ordinary skill in the art would find it obvious to modify the flow battery of Min, such that it comprises the method of “preventing a mixed electrolyte from flowing past the negative electrode by isolating the negative electrode from the mixed electrolyte,” because Song teaches or at least suggests cleansing only when the SOC estimate indicates it would be beneficial improves control and battery efficiency.
Modified Min teaches the isolation of two electrolytic mixtures but does not directly teach “partially or fully charging the battery system before preventing the mixed electrolyte from flowing past the negative electrode.”
Song II teaches an iron redox flow battery (IFB), wherein “[0019] As discussed above, the negative electrolyte used in the all iron redox flow battery (IFB) may provide a sufficient amount of Fe2+ so that, during charge, Fe2+ can accept two electrons from the negative electrode to form Fe0 and plate onto a substrate,” and the flow battery 10 comprises sensors which supply information about an SOC after “[0052] charge, discharge, and idle modes.” Song II at [0052]. Song II teaches the cleansing mode is activated in response to battery capacity being lower than a threshold (e.g. 90%) compared to an SOC as detected by the sensors. Id. at [0053]. Next, “[0059] During the cleansing mode, electrolyte may initially flow from the second electrolyte circuit 282 to the first electrolyte circuit 280 . This may include opening the first mixing valve 210 and activating the negative electrolyte pump 30 to draw electrolyte from the second electrolyte circuit 282 to the first electrolyte circuit 280 . Furthermore, the positive electrolyte pump 32 may be deactivated.” In other words, negative electrolyte is provided and plating occurs onto the negative electrode 26. This process is the “[0060] first threshold duration.” Next, “[0067] As a further example, additionally or alternatively, during the time delay following the first threshold duration, the second mixing valve 310 and the first mixing valve 210 are moved to closed positions, thereby fluidly isolating the first 280 and second 282 electrolyte circuits from one another. However, by arranging the second mixing valve 310 in the location of the orifice 220 of FIG. 2, the positive electrolyte pump 32 may be active during the time delay.” This indicates a step of plating which occurs before isolation, or, “partially or fully charging the battery system before preventing the mixed electrolyte from flowing past the negative electrode.” Song II teaches its method of cleansing “[0008] may maintain increased redox flow battery system electrolyte health, including reduced battery system capacity degradation caused by repeated and cyclic charging and discharging, as compared with conventional battery systems. In particular, the systems and methods described herein enable operation of redox flow battery systems for an increased number of cycles without experiencing a loss of capacity greater than a threshold capacity loss. Furthermore, the methods and systems described herein may be performed while utilizing existing electrolyte storage chambers, and without further additional electrolyte storage tanks, thereby reducing a system complexity and cost.”
One of ordinary skill in the art before the effective filing date of the claimed invention would find it obvious to further modify the method of modified Min, such that includes the step “partially or fully charging the battery system before preventing the mixed electrolyte from flowing past the negative electrode” in the claimed sequence, because Song II teaches a benefit to improved electrolyte health and capacity due to its cleansing methodology.
Claim 1 is obvious over Min, in view of Song and Song II.
Claims 2 – 7, 9 – 12, 14 – 17, and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Min, in view of Song and Song II, as applied to Claim 1, and further in view of Evans (US2014363747A1).
Regarding Claim 2, Claim 2 relies upon Claim 1. Claim 1 is obvious over modified Min.
Min teaches an “upper system” of the device for regenerating a flow electrolyte liquid, wherein the upper system 100 contains the cathode and anode cells 103 and 104 and the anode and cathode electrolyte liquid storage units 101 and 102, whereas the lower system contains the mixed electrolyte storage unit 108 and the cell system utilized to reduce or oxidize the mixed electrolyte, as well as an aqueous acids storage unit 109. Min at [0035]. Circulation through this lower system 200 would read upon “circulation through the battery system,” without necessarily flowing past the negative electrode of the upper system 100.
Min is silent as to lowering the pH of the mixed electrolyte using hydrogen gas.
Evans teaches an electrolyte rebalancing system for a redox flow battery system, comprising directing hydrogen gas generated on the negative electrode of the redox flow battery system to a catalyst surface (catalyst bed 234), and fluidly contacting the hydrogen gas with the positive electrolyte comprising a metal ion at the catalyst surface (catalyst bed 234). Evans at [0005, 41- 44]. Evans reads upon a “separate hydrogen gas recombination system,” comprising hydrogen gas source 220, trickle bed reactor 230, diluent source 210, and metering device 222, which then return these products to the electrolyte source 240. Id. Evans is silent as to the mixed electrolyte. Evans teaches a benefit to simplicity and cost by utilizing waste hydrogen gas and utilizing this to maintain the pH and state of charge balance. Id. Evans further discloses acid from an external acid tank may be utilized to reduce precipitate formation in the electrolytes, providing a benefit to buildup of precipitate. Id. at [0021].
One of ordinary skill would find it obvious to modify the method of Min, such that it comprises lowering the pH of the mixed electrolyte of Min using hydrogen gas in a separate hydrogen gas recombination system (the hydrogen gas source 220, and packed catalyst bed 234) of Evans, comprising the mixed electrolyte of Min; and circulating the mixed electrolyte having the lower pH through the (lower) battery system of Min, while no mixed electrolyte is flowing past the negative electrode (of the upper system of Min) to remove precipitates, rust, or both, (i.e., by mixing the mixed electrolyte in the lower system with the aqueous acid of Min, because Evans teaches a benefit to the removal of precipitates) before apportioning the mixed electrolyte (as previously taught by the method of Min). This would be obvious because Evans teaches a benefit to lower cost and complexity, as well as reducing precipitate buildup. As such, Claim 2 is obvious over Min, in view of Song and Song II , further in view of Evans.
Regarding Claim 3, Claim 3 relies upon Claim 1. Claim 1 is obvious over modified Min.
Evans teaches an all iron redox flow battery, which may allow “the electrons provided to the negative electrode 26 (e.g., plating electrode) can reduce the Fe2+ in the negative electrolyte to form Fe0 at the plating substrate causing it to plate onto the negative electrode. [0029] Discharge can be sustained while Fe0 remains available to the negative electrolyte for oxidation and while Fe3+ remains available in the positive electrolyte for reduction.” Evans at [0028]. As modified, this step is prior to that of preventing the mixed electrolyte from flowing past the negative electrolyte, prior to the mixing of the spent electrolyte liquid into a mixed electrolyte as in Min. As such, Claim 3 is obvious over Min, in view of Song and Song II , further in view of Evans.
Regarding Claim 4, Claim 4 relies upon Claim 1. Claim 1 is obvious over modified Min.
Regarding the term, “resuming a flow of the refreshed negative electrolyte past the negative electrode” Min teaches “[0121] When the flow battery is a vanadium battery, metal ions comprised in the electrolyte liquid are in a state where V4+ and V3+ in a fully discharged state are mixed with each other after the dividing, and therefore, the re-operating of the flow battery may be charging the flow battery first, and then operating through repeating charge and discharge.” While this does not include the Fe as selected, “re-operating,” reads upon “resuming a flow,” and because the flow comprises a flow along the negative electrode (see Fig. 1), this reads upon, “resuming a flow of the refreshed negative electrolyte past the negative electrode.” The further limitations of Claim 4, “discharging the battery system after resuming the flow of the refreshed negative electrolyte past the negative electrode,” would logically be included within “repeating charge and discharge,” given at least one instance of discharge takes place after the resumption of flow.
As such, Claim 4 is obvious over Min, in view of Song and Song II , further in view of Evans.
Regarding Claim 5, Claim 5 relies upon Claim 1. Claim 1 is obvious over modified Min.
Min teaches a “a fully charged state (SOC: 100)” of the flow battery, which reads upon “providing the completely discharged or at least partially charged redox flow battery system comprises providing a fully charged redox flow battery system.” Min at [0057].
As such, Claim 5 is obvious over Min, in view of Song and Song II , further in view of Evans.
Regarding Claim 6, Claim 6 relies upon Claim 1. Claim 1 is obvious over modified Min. 6.
Min and Evans teach the metal of the liquid electrolyte comprise iron. Min at [0056], Evans at [0026].
Song teaches an all-iron flow battery. Song at [0018 – 22].
As such, Claim 6 is obvious over Min, in view of Song and Song II, further in view of Evans.
Regarding Claim 7, Claim 7relies upon Claim 1. Claim 1 is obvious over modified Min.
Evans teaches the metal comprises iron and wherein the metal precursor comprises FeCl2, FeCl3, FeSO4, Fe2(SO4)3, FeO, Fe, Fe203, or combinations thereof. Evans at [0026] (“[0026] One example of a hybrid redox flow battery is an all iron redox flow battery (IFB), in which the electrolyte comprises iron ions in the form of iron salts (e.g., FeCl2 , FeCl3 , and the like), wherein the negative electrode comprises metal iron.”).
Song also teaches an all-iron flow battery. Song at [0018 – 22].
As such, Claim 7 is obvious over Min, in view of Song and Song II, further in view of Evans.
Regarding Claim 9, Claim 9 relies upon Claim 1. Claim 1 is obvious over modified Min.
Evans teaches “[t]he separator 24 may comprise an electrically insulating ionic conducting barrier which prevents bulk mixing of the positive electrolyte and the negative electrolyte while allowing conductance of specific ions therethrough.” Evans at [0019].
As such, Claim 9 is obvious over Min, in view of Song and Song II, further in view of Evans.
Regarding Claim 10, Claim 10 relies upon Claim 1. Claim 1 is obvious over modified Min.
Evans teaches “[t]he separator 24 may comprise an electrically insulating ionic conducting barrier which prevents bulk mixing of the positive electrolyte and the negative electrolyte while allowing conductance of specific ions therethrough . . . For example, the separator 24 may comprise an ion-exchange membrane or a microporous membrane.” Evans at [0019].
Min teaches an “[0066] anion separator” or a “[0066] cation separator.”
Taken together, this reads upon “the ionically conductive membrane comprises an ionically conductive thin film composite membrane, an ionically conductive asymmetric composite membrane, a size exclusion membrane, an anion exchange membrane, or a cation exchange membrane.”
As such, Claim 10 is obvious over Min, in view of Song and Song II, further in view of Evans.
Regarding Claim 11, Claim 11 relies upon Claim 1. Claim 1 is obvious over modified Min.
Min teaches an aqueous acid solution containing sulfuric acid, hydrochloric acid, nitric acid, or a mixture thereof, which reads upon “the positive electrolyte, the negative electrolyte, or both further comprise at least one of . . . an inorganic acid.” Min at [0010].
As such, Claim 11 is obvious over Min, in view of Song and Song II, further in view of Evans.
Regarding Claim 12, Claim 12 relies upon Claim 1. Claim 1 is obvious over modified Min.
Min teaches an aqueous acid solution containing sulfuric acid, hydrochloric acid, nitric acid, or a mixture thereof, which reads upon “the inorganic acid comprises HCl, H2SO4, or combinations thereof.” Min at [0010].
As such, Claim 12 is obvious over Min, in view of Song and Song II, further in view of Evans.
Regarding Claim 14, Min teaches a method of refreshing an asymmetric redox flow battery system comprising wherein the metal redox flow battery system comprises: at least one rechargeable cell (anode and cathode cells 103, 104) comprising a positive electrolyte (“cathode electrolyte liquid 104a”), a negative electrolyte (“cathode electrolyte liquid 103a”), and a separator (“separator 105”) positioned between the positive electrolyte and the negative electrolyte (Fig. 1), the positive electrolyte in contact with a positive electrode, and the negative electrolyte in contact with a negative electrode (“[0006] A flow battery is configured so as to place cathode and anode electrodes on both sides with a separator as a center”); the positive electrolyte comprising water and a metal precursor and having a volume (“[0056] the electrolyte liquid active material of the flow battery may be any one of vanadium ions, titanium ions, chromium ions, manganese ions, iron . . . [0058] The solvent is not particularly limited as long as it is capable of dissolving the electrolyte liquid active material, and examples thereof may comprise an aqueous sulfuric acid solution, an aqueous hydrochloric acid solution, an aqueous nitric acid solution and a mixed solution thereof” where aqueous teaches a solvent containing water); the negative electrolyte comprising water and the metal precursor and having a volume (see prior; because “the” metal precursor is claimed, this must be the same material, for example an Fe / Fe redox flow battery, and Fe ions are taught as an option within the Markush groups); and preventing a mixed electrolyte from flowing past the negative electrode (see below); mixing the positive electrolyte and the negative electrolyte to form the mixed electrolyte having a concentration of metal precursor between the concentration of the metal precursor in the positive electrolyte and the concentration in the negative electrolyte (“[0009] mixing the anode electrolyte liquid and the cathode electrolyte liquid of the flow battery ; electrically oxidizing or reducing the mixed electrolyte liquid” ; because the metal precursor is the same substance, the concentration must be “between” the two concentrations as the reduction or oxidation reaction occurs); apportioning the mixed electrolyte based on the negative electrolyte volume and the positive electrolyte volume to form a refreshed negative electrolyte and a refreshed positive electrolyte (“[0009] dividing the oxidized or reduced electrolyte liquid into each of the cathode electrolyte liquid storage unit and the anode electrolyte liquid storage unit”). Min at [006, 9, 56, 58, 72 – 84].
Examiner notes the preamble recites an asymmetric redox flow battery system. While “asymmetric,” is not used as a descriptor, an asymmetric redox flow battery configuration is one in which a selective membrane and having separated electrolytes, is utilized to hinder crossover between catholyte and anolyte. See, e.g. Shrestha, et. al., Realization of an Asymmetric Non-Aqueous Redox Flow Battery through Molecular Design to Minimize Active Species Crossover and Decomposition, Chem. Eur. J. 2020, 26, 5369. As such, Min teaches an asymmetric redox flow battery system.
Regarding the term, “the negative electrolyte having a concentration of the metal precursor greater than a concentration of the metal precursor in the positive electrolyte,” Min teaches unbalanced states “an unbalanced state with relatively more ion amounts in the cathode electrolyte liquid,” as well as “in an unbalanced state with relatively more ion amounts in the anode electrolyte liquid,” at least suggesting an unbalanced state wherein the negative electrolyte having a concentration of the metal precursor greater than a concentration of the metal precursor in the positive electrolyte. Min at [0076]. Min teaches this may be within the “fully discharged state,” indicating this step falls within the required order of the method, i.e. taking place after complete or partial discharge but prior to mixing of the electrolyte. Id.
Regarding the term, “resuming a flow of the refreshed negative electrolyte past the negative electrode” Min teaches “[0121] When the flow battery is a vanadium battery, metal ions comprised in the electrolyte liquid are in a state where V4+ and V3+ in a fully discharged state are mixed with each other after the dividing, and therefore, the re-operating of the flow battery may be charging the flow battery first, and then operating through repeating charge and discharge.” While this does not include the Fe as selected, “re-operating,” reads upon “resuming a flow,” and because the flow comprises a flow along the negative electrode (see Fig. 1), this reads upon, “resuming a flow of the refreshed negative electrolyte past the negative electrode.”
Regarding the term, “preventing a mixed electrolyte from flowing past the negative electrode,” this is interpreted as preventing the mixing of the electrolyte prior to the mixing step, which is accomplished by the selective membrane 105 during normal operation. See id at Fig. 1, [0035].
Min additionally teaches “[0011] The present specification has an advantage of recovering battery capacity by regenerating an electrolyte liquid of which performance declines due to a membrane permeation phenomenon and an unintended oxidation/reduction reaction. [0012] The present specification has an advantage of recovering battery capacity even when the degree of ion imbalance of an electrolyte liquid is high.” Min at [0011-12].
While Min provides a suggestion of an unbalanced state prior to the mixing stage, Min does not disclose the specific unbalanced state of “the negative electrolyte having a concentration of the metal precursor greater than a concentration of the metal precursor in the positive electrolyte,” despite presenting the unbalanced state in the correct order of steps.
Min is silent as to preventing a mixed electrolyte from flowing past the negative electrode by isolating the negative electrode from the mixed electrolyte.
Song teaches an all-iron flow battery, having a negative electrolyte (“[0018] FeCl2, FeCl3, FeSO4, Fe2(SO4)3 and the like”) within the plating side (e.g., negative reactor 122), referred to as a plating electrolyte, and a positive electrolyte on the redox side (e.g. positive reactor 124) referred to as the redox electrolyte. Song at [0018 – 20]. Further, Song teaches “both the plating electrolyte and redox electrolyte may use the same salt at different molar concentrations, a feature of the IFB not available in batteries with different reactive compounds.” Id. In addition, Song teaches “[0022] During normal operation (e.g., not during a cleansing cycle), first three-way valve 170 prevents flow of plating electrolyte through bypass passage 180 and permits flow of plating electrolyte from negative reactor 122 to pump 131 as indicated by arrow 177. Similarly, during normal operation, second three-way valve 171 prevents flow of redox electrolyte through bypass passage 181 and permits flow of redox electrolyte from positive reactor 124 to pump 130 as indicated by arrow 178. Thus, plating electrolyte is separated and isolated from redox electrolyte. [0023] During a cleansing cycle, it may be desirable to mix plating electrolyte with redox electrolyte. The mixing may be accomplished via positioning first three-way valve 170 and second three-way valve 171 to second positions. While operating in their second positions, first valve 170 permits plating electrolyte to flow through bypass passage 180 as indicated by arrow 172 and prevents plating electrolyte from flowing from negative reactor 122 to pump 131 . Similarly, while in a second position, second valve 171 permits plating electrolyte to flow through bypass passage 181 as indicated by arrow 173 and prevents plating electrolyte from flowing from positive reactor 124 to pump 130. Valves 170 and 171 may be adjusted between first and second positions via controller 150.” Id. at [0022]. This reads upon “isolating the negative electrode from the mixed electrolyte,” because the mixed electrolyte is not generated until a later “cleansing” step, and a valve isolates the negative electrode. Song also teaches the measurement of SOC via a control system and sensors. Song at [0020-22]. Finally, Song teaches “[0007] The present description may provide several advantages. In particular, the approach may improve SOC estimates for an oxidation-reduction flow battery. Further, the approach may be useful to improve control of an oxidation-reduction flow battery. In addition, the approach may be useful to determine when it may be desirable to perform an oxidation-reduction flow battery cleansing procedure to improve battery cell efficiency.” Id. at [0007]. This teaches or at least suggests a benefit to preventing cleansing or mixing of the electrolyte via isolation (accomplished by the valve apparatus) until the SOC estimate indicates mixing the electrolytes would be beneficial.
However, Song does not directly disclose “mixing the positive electrolyte and the negative electrolyte to form the mixed electrolyte having a concentration of metal precursor between the concentration of the metal precursor in the positive electrolyte and the concentration in the negative electrolyte; apportioning the mixed electrolyte based on the negative electrolyte volume and the positive electrolyte volume to form a refreshed negative electrolyte and a refreshed positive electrolyte; and resuming a flow of the refreshed negative electrolyte past the negative electrode.”
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Fig. 1 of Song.
One of ordinary skill would find it obvious to modify the method of Min, such that the unbalanced step prior to the mixing of the electrolyte liquid comprises the negative electrolyte having a concentration of the metal precursor greater than a concentration of the metal precursor in the positive electrolyte, because Min teaches its process has an advantage of recovering battery capacity even when the degree of ion balance of an electrolyte liquid is high and because one of ordinary skill would not anticipate new or unexpected results by specifying a higher precursor concentration in the negative electrolyte. See MPEP 2144.065 IV(C). One of ordinary skill in the art would also find it obvious to modify the flow battery of Min, such that it comprises the method of Song wherein “preventing a mixed electrolyte from flowing past the negative electrode by isolating the negative electrode from the mixed electrolyte,” because Song teaches or at least suggests cleansing only when the SOC estimate indicates it would be beneficial improves control and battery efficiency.
However, Modified Min is silent as to charging the battery to plate metal on a negative electrode, wherein the metal comprises iron, copper, or zinc.
Evans teaches an electrolyte rebalancing system for a redox flow battery system (which may be an all iron flow battery), comprising directing hydrogen gas generated on the negative electrode of the redox flow battery system to a catalyst surface (catalyst bed 234), and fluidly contacting the hydrogen gas with the positive electrolyte comprising a metal ion at the catalyst surface (catalyst bed 234). Evans at [0005, 41- 44]. Evans reads upon a “separate hydrogen gas recombination system,” comprising hydrogen gas source 220, trickle bed reactor 230, diluent source 210, and metering device 222, which then return these products to the electrolyte source 240. Id. Evans is silent as to the mixed electrolyte. Evans teaches a benefit to simplicity and cost by utilizing waste hydrogen gas and utilizing this to maintain the pH and state of charge balance. Id. Evans further discloses acid from an external acid tank may be utilized to reduce precipitate formation in the electrolytes, providing a benefit to buildup of precipitate. Id. at [0021].
One of ordinary skill would further find it obvious to modify the method of Min, such that it comprises the iron flow battery structure of Evans, because Evans teaches a benefit to the removal of precipitates. This would be obvious because Evans teaches a benefit to lower cost and complexity, as well as reducing precipitate buildup.
Modified Min teaches the isolation of two electrolytic mixtures but does not directly teach “charging the battery system to plate metal on the negative electrode before preventing the mixed electrolyte from flowing past the negative electrode.”
Song II teaches an iron redox flow battery (IFB), wherein “[0019] As discussed above, the negative electrolyte used in the all iron redox flow battery (IFB) may provide a sufficient amount of Fe2+ so that, during charge, Fe2+ can accept two electrons from the negative electrode to form Fe0 and plate onto a substrate,” and the flow battery 10 comprises sensors which supply information about an SOC after “[0052] charge, discharge, and idle modes.” Song II at [0052]. Song II teaches the cleansing mode is activated in response to battery capacity being lower than a threshold (e.g. 90%) compared to an SOC as detected by the sensors. Id. at [0053]. Next, “[0059] During the cleansing mode, electrolyte may initially flow from the second electrolyte circuit 282 to the first electrolyte circuit 280 . This may include opening the first mixing valve 210 and activating the negative electrolyte pump 30 to draw electrolyte from the second electrolyte circuit 282 to the first electrolyte circuit 280 . Furthermore, the positive electrolyte pump 32 may be deactivated.” In other words, negative electrolyte is provided and plating occurs onto the negative electrode 26. This process is the “[0060] first threshold duration.” Next, “[0067] As a further example, additionally or alternatively, during the time delay following the first threshold duration, the second mixing valve 310 and the first mixing valve 210 are moved to closed positions, thereby fluidly isolating the first 280 and second 282 electrolyte circuits from one another. However, by arranging the second mixing valve 310 in the location of the orifice 220 of FIG. 2, the positive electrolyte pump 32 may be active during the time delay.” This indicates a step of plating which occurs before isolation, or, “charging the battery system to plate metal on the negative electrode before preventing the mixed electrolyte from flowing past the negative electrode.” Song II teaches its method of cleansing “[0008] may maintain increased redox flow battery system electrolyte health, including reduced battery system capacity degradation caused by repeated and cyclic charging and discharging, as compared with conventional battery systems. In particular, the systems and methods described herein enable operation of redox flow battery systems for an increased number of cycles without experiencing a loss of capacity greater than a threshold capacity loss. Furthermore, the methods and systems described herein may be performed while utilizing existing electrolyte storage chambers, and without further additional electrolyte storage tanks, thereby reducing a system complexity and cost.”
One of ordinary skill in the art before the effective filing date of the claimed invention would find it obvious to further modify the method of modified Min, such that includes the step “charging the battery system to plate metal on the negative electrode before preventing the mixed electrolyte from flowing past the negative electrode” in the claimed sequence, because Song II teaches a benefit to improved electrolyte health and capacity due to its cleansing methodology.
As such, Claim 14 is obvious over Min, in view of Song and Song II, further in view of Evans.
Regarding Claim 15, Claim 15 relies upon Claim 14. Claim 14 is obvious over modified Min.
Min teaches an “upper system” of the device for regenerating a flow electrolyte liquid, wherein the upper system 100 contains the cathode and anode cells 103 and 104 and the anode and cathode electrolyte liquid storage units 101 and 102, whereas the lower system contains the mixed electrolyte storage unit 108 and the cell system utilized to reduce or oxidize the mixed electrolyte, as well as an aqueous acids storage unit 109. Min at [0035]. Circulation through this lower system 200 would read upon “circulation through the battery system,” without necessarily flowing past the negative electrode of the upper system 100.
Min is silent as to lowering the pH of the mixed electrolyte using hydrogen gas.
Evans teaches an electrolyte rebalancing system for a redox flow battery system, comprising directing hydrogen gas generated on the negative electrode of the redox flow battery system to a catalyst surface (catalyst bed 234), and fluidly contacting the hydrogen gas with the positive electrolyte comprising a metal ion at the catalyst surface (catalyst bed 234). Evans at [0005, 41- 44]. Evans reads upon a “separate hydrogen gas recombination system,” comprising hydrogen gas source 220, trickle bed reactor 230, diluent source 210, and metering device 222, which then return these products to the electrolyte source 240. Id. Evans is silent as to the mixed electrolyte. Evans teaches a benefit to simplicity and cost by utilizing waste hydrogen gas and utilizing this to maintain the pH and state of charge balance. Id. Evans further discloses acid from an external acid tank may be utilized to reduce precipitate formation in the electrolytes, providing a benefit to buildup of precipitate. Id. at [0021].
One of ordinary skill would find it obvious to modify the method of Min, such that it comprises lowering the pH of the mixed electrolyte of Min using hydrogen gas in a separate hydrogen gas recombination system (the hydrogen gas source 220, and packed catalyst bed 234) of Evans, comprising the mixed electrolyte of Min; and circulating the mixed electrolyte having the lower pH through the (lower) battery system of Min, while no mixed electrolyte is flowing past the negative electrode (of the upper system of Min) to remove precipitates, rust, or both, (i.e., by mixing the mixed electrolyte in the lower system with the aqueous acid of Min, because Evans teaches a benefit to the removal of precipitates) before apportioning the mixed electrolyte (as previously taught by the method of Min). This would be obvious because Evans teaches a benefit to lower cost and complexity, as well as reducing precipitate buildup.
As such, Claim 15 is obvious over Min, in view of Song and Song II, further in view of Evans.
Regarding Claim 16, Claim 16 relies upon Claim 14. Claim 14 is obvious over modified Min.
Regarding the term, “resuming a flow of the refreshed negative electrolyte past the negative electrode” Min teaches “[0121] When the flow battery is a vanadium battery, metal ions comprised in the electrolyte liquid are in a state where V4+ and V3+ in a fully discharged state are mixed with each other after the dividing, and therefore, the re-operating of the flow battery may be charging the flow battery first, and then operating through repeating charge and discharge.” While this does not include the Fe as selected, “re-operating,” reads upon “resuming a flow,” and because the flow comprises a flow along the negative electrode (see Fig. 1), this reads upon, “resuming a flow of the refreshed negative electrolyte past the negative electrode.” The further limitations of Claim 16, “discharging the battery system after resuming the flow of the refreshed negative electrolyte past the negative electrode,” would logically be included within “repeating charge and discharge,” given at least one instance of discharge takes place after the resumption of flow.
As such, Claim 16 is obvious over Min, in view of Song and Song II, further in view of Evans.
Regarding Claim 17, Claim 7relies upon Claim 14. Claim 1 is obvious over modified Min.
Evans teaches the metal comprises iron and wherein the metal precursor comprises FeCl2, FeCl3, FeSO4, Fe2(SO4)3, FeO, Fe, Fe203, or combinations thereof. Evans at [0026] (“[0026] One example of a hybrid redox flow battery is an all iron redox flow battery (IFB), in which the electrolyte comprises iron ions in the form of iron salts (e.g., FeCl2 , FeCl3 , and the like), wherein the negative electrode comprises metal iron.”).
As such, Claim 17 is obvious over Min, in view of Song and Song II, further in view of Evans.
Regarding Claim 19, Claim 19 relies upon Claim 14. Claim 14 is obvious over modified Min.
Min teaches an aqueous acid solution containing sulfuric acid, hydrochloric acid, nitric acid, or a mixture thereof, which reads upon “the positive electrolyte, the negative electrolyte, or both further comprise at least one of . . . an inorganic acid.” Min at [0010]. Min teaches an aqueous acid solution containing sulfuric acid, hydrochloric acid, nitric acid, or a mixture thereof, which reads upon “the inorganic acid comprises HCl, H2SO, or combinations thereof.” Min at [0010].
As such, Claim 19 is obvious over Min, in view of Song and Song II, further in view of Evans.
Claims 8, 13, 18, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Min, in view of Song, Song II, and Evans, and further in view of Selverston, et. al. (WO 2019246538 A1).
Regarding Claim 8, Claim 8 relies upon Claim 1. Claim 1 is obvious over modified Min.
Min and Evans are silent as to the precise amount of metal precursor within the electrolytes, but Evans teaches an iron flow battery comprising FeCl2 within its electrolyte liquid.
Selverston teaches an all-iron flow battery, having a positive and negative electrolyte, wherein “[0061] a flow cell of the invention comprises FeCl2 at a concentration between 0.1 and 5 M . . . In some embodiments, a flow cell of the invention comprises FeCl3 at a concentration between 0.1 and 5 M.” Selverston at [0061]. Selverston also teaches the use of additives such as KCl and NH4Cl. Id. at [0018]. Selverston teaches this system may be utilized with pH balancing or chemical rebalancing. Id. at [0066 – 68]. Selverston teaches the use of this range improves current efficiency (see [0091]) and the use of additives may improve solubility and/or hinder precipitation. Id. at [0062].
Selverston reads upon “the metal precursor in the negative electrolyte comprises FeCl2 at the concentration of 1.0-4.5 M; and the metal precursor in the positive electrolyte comprises FeCl2, at the concentration of 0.5-4.0 M,” because an overlapping range presents a prima facie case of obviousness. MPEP 2144.05.
One of ordinary skill in the art would find it obvious to further modify the electrolytes of Min with the concentration range of Selverston, because Selverston teaches a benefit to current efficiency and solubility, and because an overlapping range presents a prima facie case of obviousness. MPEP 2144.05.
As such, Claim 8 is obvious over Min, in view of Song, Song II and Evans, and further in view of Selverston.
Regarding Claim 13, Claim 8 relies upon Claim 1. Claim 1 is obvious over modified Min.
Selverston teaches an all-iron flow battery, having a positive and negative electrolyte, wherein “[0061] a flow cell of the invention comprises FeCl2 at a concentration between 0.1 and 5 M . . . In some embodiments, a flow cell of the invention comprises FeCl3 at a concentration between 0.1 and 5 M.” Selverston at [0061]. Selverston also teaches the use of additives such as KCl and NH4Cl. Id. at [0018]. Selverston teaches this system may be utilized with pH balancing or chemical rebalancing. Id. at [0066 – 68]. Selverston teaches the use of this range improves current efficiency (see [0091]) and the use of additives may improve solubility and/or hinder precipitation. Id. at [0062].
Selverston reads upon “the negative electrolyte comprises FeCl2 at the concentration of 1.0-4.5 M; and NaCl, KCl, NH4Cl or combinations thereof. . . ; and the positive electrolyte comprises FeCl2 at the concentration of 0.5-4.0 M; and NaCl, KCl, NH4Cl, or combinations thereof” because an overlapping range presents a prima facie case of obviousness. MPEP 2144.05.
As such, Claim 13 is obvious over Min, in view of Song, Song II and Evans, and further in view of Selverston.
Regarding Claim 18, Claim 18 relies upon Claim 14. Claim 14 is obvious over modified Min.
Min and Evans are silent as to the precise amount of metal precursor within the electrolytes, but Evans teaches an iron flow battery comprising FeCl2 within its electrolyte liquid.
Selverston teaches an all-iron flow battery, having a positive and negative electrolyte, wherein “[0061] a flow cell of the invention comprises FeCl2 at a concentration between 0.1 and 5 M . . . In some embodiments, a flow cell of the invention comprises FeCl3 at a concentration between 0.1 and 5 M.” Selverston at [0061]. Selverston also teaches the use of additives such as KCl and NH4Cl. Id. at [0018]. Selverston teaches this system may be utilized with pH balancing or chemical rebalancing. Id. at [0066 – 68]. Selverston teaches the use of this range improves current efficiency (see [0091]) and the use of additives may improve solubility and/or hinder precipitation. Id. at [0062].
Selverston reads upon “the metal precursor in the negative electrolyte comprises FeCl2 at the concentration of 1.0-4.5 M; and the metal precursor in the positive electrolyte comprises FeCl2, at the concentration of 0.5-4.0 M,” because an overlapping range presents a prima facie case of obviousness. MPEP 2144.05.
One of ordinary skill in the art would find it obvious to further modify the electrolytes of Min with the concentration range of Selverston, because Selverston teaches a benefit to current efficiency and solubility, and because an overlapping range presents a prima facie case of obviousness. MPEP 2144.05.
As such, Claim 18 is obvious over Min, in view of Song, Song II, and Evans, and further in view of Selverston.
Regarding Claim 20, Claim 20 relies upon Claim 14. Claim 14 is obvious over modified Min.
Selverston teaches an all-iron flow battery, having a positive and negative electrolyte, wherein “[0061] a flow cell of the invention comprises FeCl2 at a concentration between 0.1 and 5 M . . . In some embodiments, a flow cell of the invention comprises FeCl3 at a concentration between 0.1 and 5 M.” Selverston at [0061]. Selverston also teaches the use of additives such as KCl and NH4Cl. Id. at [0018]. Selverston teaches this system may be utilized with pH balancing or chemical rebalancing. Id. at [0066 – 68]. Selverston teaches the use of this range improves current efficiency (see [0091]) and the use of additives may improve solubility and/or hinder precipitation. Id. at [0062].
Selverston reads upon “the negative electrolyte comprises FeCl2 at the concentration of 1.0-4.5 M; and NaCl, KCl, NH4Cl or combinations thereof. . . ; and the positive electrolyte comprises FeCl2 at the concentration of 0.5-4.0 M; and NaCl, KCl, NH4Cl, or combinations thereof” because an overlapping range presents a prima facie case of obviousness. MPEP 2144.05.
As such, Claim 20 is obvious over Min, in view of Song, Song II, and Evans, and further in view of Selverston.
Response to Arguments
Applicant’s arguments with respect to claims 1-20 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/K.R.H./Examiner , Art Unit 1725
/NICOLE M. BUIE-HATCHER/Supervisory Patent Examiner, Art Unit 1725