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 .
Response to Amendment
Applicant amended claims 1, 15, and 18; claims 1-4, and 7-20 are pending and considered in the present Office action.
The rejections of the claims are withdrawn in view of the amendments. However, upon further consideration a new ground of rejection is necessitated by amendment.
Response to Arguments
Applicant’s arguments with respect to the claim(s) 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.
Claim Rejections - 35 USC § 103
Claim(s) 1-3, 7-8, 12, and 16-19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Bhavaraju (US 2014/0356654) in view of Nakabayashi et al. (US 4,027,075), Park et al. (US 2016/0240890), and Winn (US 3,533,848), hereinafter Bhavaraju, Nakabayashi, Park, and Winn.
Regarding Claims 1-3, 7, 12 and 18-19, Bhavaraju teaches a method of operating a rechargeable galvanic cell (e.g., 100, Figs. 1-2), the method comprising: providing a rechargeable galvanic cell comprising a negative electrode compartment housing a negative electrode active material (e.g., 124, see Figs. 1-2, 4A-4B) , wherein the negative electrode active material comprises a liquid alkali metal (i.e., molten Na [0025]; please note, while Fig. 4A shows "Solid Na" due to the temperature, i.e., cold start/-30 °C, the disclosure explains the cell is heated to about 100 °C (see e.g., Fig. 3); considering sodium melts at 98 °C (inherent melting point), Bhavaraju suggests the cell operates upon discharge when the negative electrode active material is liquid (molten Na) around 100 °C, thereby having greater power and current density, [0004-0005, 0012, 0043-0044, 0046]). It is further noted upon charge, the cell is cooled to about 100 °C (see Fig. 3); thus, Bhavaraju suggests the cell operates upon charge when the negative electrode active material is liquid (molten Na) around 100 °C. Bhavaraju suggests the negative electrode compartment (124) is in fluid communication with a first reservoir (i.e., 142, see Fig. 1) such that the liquid alkali metal may flow between the negative electrode compartment and the first reservoir as the galvanic cell charges or discharges, see [0037]. While Bhavaraju does not explicitly suggest the flow is passive through a conduit, one of ordinary skill in the art would understand such construction and behavior for the first reservoir 142 of Bhavaraju based on what is known (functionally about the cell) and common practice in the art. Nakabayashi explains during charging and discharging of sodium sulfur cells, pressure changes necessitate molten sodium (11) to move back and forth through a conduit (21’) from the negative electrode compartment (11’) to a reservoir (5). It would be obvious to one having ordinary skill in the art a conduit between the first reservoir and the negative electrode compartment allows passive flow during charging and discharging to accommodate the pressure fluctuations expected in the cell, as suggested by Nakabayashi.
Bhavaraju further suggests a positive electrode compartment housing a positive electrolyte (e.g., 114) comprising a mixture of positive electrode active material and a solvent, wherein the positive electrode active material comprises Na2Sx ([0051]) depending on the charge state of the galvanic cell, wherein x has a value between 1 and 32 (i.e., x = 2, 6, 8, [0051]), the solvent comprises a polar organic solvent (e.g., tetraglyme, water, NMF, see e.g., [0018], [0051]), optionally comprising a polar protic organic solvent (i.e., NMF), that partially or completely dissolves the Na2Sx and the negative electrode compartment and the positive electrode compartment are separated by a sodium ion conductive ceramic membrane (120, Fig. 1); maintaining the temperature of the ceramic membrane, the negative electrode active material, and/or the positive electrolyte at a temperature from about 100 °C to about 130 °C (see [0012]); and charging or discharging the rechargeable galvanic cell while circulating the positive electrolyte from a second external reservoir through the positive electrode compartment and back to the second external reservoir ([0027]). Specifically, the positive electrode compartment is in fluid communication with a pump (150) and the second external reservoir (148) such that the pump may circulate the positive electrolyte between the second external reservoir and the positive electrode compartment during charge or discharge of the galvanic cell, see Fig. 2, [0023], [0042].
Bhavaraju suggest the solvent (e.g., tetraglyme, NMF, water) includes sodium salts dissolved therein to form highly sodium ion conductive solutions which allow for sufficient sodium ion transport through the solid sodium ion selective conducting separator between the electrodes during battery cycling, [0017, 0036, 0051, 0053]. Thus, Bhavaraju suggests a conductivity enhancer, but does not suggest the conductivity enhancer comprises sodium carboxylates (i.e., sodium formate (HCOONa), sodium acetate (CH3COONa)), sodium sulfur oxygenates (i.e., Na2SO4, Na2SO3 Na2S2O4), or a combination thereof, wherein the amount of the conductivity enhancer is about 0.01 wt% to 20 wt%. However, Park discloses a sodium secondary battery in which sodium ions serve as the ion conduction transport material between the electrodes during charging and discharging; further, the electrolyte includes sodium ions from salts and two additives, also serving as the ion conduction transport material, which is preferable to improve the ionic conductivity of the battery, [0009-0030, 0070, 0074]. Specifically, Park suggests the use of a first additive (i.e., sodium sulfate (Na2SO4), sodium thiosulfate (Na2S2O3), sodium sulfite (Na2SO3)) and a second additive (i.e., sodium acetate, sodium formate), which maintains the ionic conductivity, even at low temperatures (Table 1, [0008-0030, 0074]). Park’s disclosure of the amount of the first additive (i.e., 3-10 wt%) and the second additive (i.e., 0.1-3 wt%) overlaps with that claimed, see e.g., [0055-0056]. It would be obvious to one having ordinary skill in the art to use sodium carboxylates and/or a sodium sulfur oxygenate as a conductivity enhancer in an amount of 0.01 wt% to 20 wt% with the expectation of improving the ionic conductivity of the electrolyte of the battery and/or to maintain the ionic conductivity, even at low temperatures, as suggested by Park.
In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). Similarly, a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985). Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). MPEP 2144.05, I. and II.
It is unclear whether Bhavaraju explicitly suggests heating the positive electrolyte from about 100 °C to about 150 °C, or about 110 °C to about 130 °C, or heating the positive electrolyte prior to or upon entering the positive electrode compartment to a first temperature from about 100 °C to a temperature of about 200 °C. However, Bhavaraju teaches an operating temperature between 100 °C to 130 °C (or about 110 °C) offers favorable kinetics leading to higher capacity and power for both electrodes and the overall battery, [0043]. Winn suggests the sulfur zone is heated up to or near the desired operating temperature (e.g., 110 °C to 1000 °C) so that the sulfur is easily transported, see column 2 line 67 to column 3 line 9. It would be obvious to one having ordinary skill in the art to heat the positive electrolyte to a temperature from about 100 °C to a temperature of about 150 °C (or about 110 °C to about 130 °C), or from about 100 °C to a temperature of about 200 °C prior to or upon entering the positive electrode compartment with the expectation of higher capacity at both electrodes and the overall battery due to favorable kinetics, and to easily transport the positive electrolyte, as suggested by Bhavaraju and Winn.
Regarding Claim 8, Bhavaraju teaches the sodium ion conductive ceramic membrane comprises at least one of NaSICON, sodium ion conducting garnet-like ceramic, sodium p"- alumina, and a sodium conducting glass ceramic, [0026].
Regarding Claim 16, Bhavaraju teaches the rechargeable galvanic cell further comprises a positive electrode current collector (128) disposed in the positive electrode compartment and electrically connected to the positive electrode active material (110), see e.g., Fig. 1.
Regarding Claim 17, Bhavaraju teaches the positive electrode current collector comprises nickel foam, nickel mesh, carbon foam, or carbon felt ([0023] and Table 1).
Claim(s) 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Bhavaraju, Nakabayashi, Park, and Winn in view of Gordon (WO 2017117373, of record), hereinafter Gordon.
Regarding Claim 4, Bhavaraju does not teach cooling the positive electrolyte after it exits the positive electrode compartment to a temperature of about 80 °C to less than 100 °C. However, Gordon teaches an electrochemical cell operating between 100 °C to 160 °C comprising two compartments; elemental sulfur is recovered from one of the compartments. The recovery process includes removing, then cooling, the electrolyte comprising the elemental sulfur; when cooled, the solubility of elemental sulfur decreases, thereby allowing the recovery of the precipitated elemental sulfur, see e.g., [0012-0016, 0034-0039, 0046, 0050-0055, 0057-0062, 0064, 0065, 0072, 0074-0077]. It would be obvious to one having ordinary skill in the art to cool the positive electrolyte after it exits the positive electrode compartment below the operating temperature of the cell (i.e., 100 °C) to decrease the solubility of the elemental sulfur, thereby allowing the recovery of the precipitated elemental sulfur from the cathode compartment (i.e., during charge), as suggested by Gordon.
Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Bhavaraju, Nakabayashi, Park, and Winn, further in view of Bhavaraju (US 2014/0212707, of record), hereinafter Bhavaraju II.
Regarding Claim 9, Bhavaraju does not disclose the conductivity of the positive electrolyte. However, like Bhavaraju, Bhavaraju II teaches using NaSICON as the separating membrane between two compartments of a molten sodium secondary battery; the sodium ion conductivity of the membrane is 20 to 50 mS/cm. Further, the positive electrolyte has a higher sodium ion conductivity (i.e., 50 mS/cm to 100 mS/cm) than the electrolyte membrane, thereby providing good sodium ion conductivity that allows the cell to function (sodium ion transport between the electrodes). Further, Park suggests electrolyte conductivity is 140 ms/cm or more (e.g., 300ms/cm or more, [0057]) where a cycle characteristic may be improved with the high ionic conductivity ([0092]). It would be obvious to one having ordinary skill in the art the positive electrolyte has high sodium ion conductivity of at least 30 mS/cm (i.e., 50-100 mS/cm, 140 ms/cm or more, etc.), as suggested by Park and Bhavaraju II, with the expectation of providing good sodium ion conductivity that allows the cell to function, where the high ionic conductivity is expected to improve a cycle characteristic.
Claim(s) 10-11, and 13-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Bhavaraju, Nakabayashi, Park, and Winn in view of Yang (US 2013/0288153), and Chae et al. (US 2016/0049658), hereinafter Yang and Chae.
Regarding Claims 10-11, Bhavaraju does not teach the polar organic solvent comprises one or more of 1,3- propanediol,1,4-butanediol, dihydroxybenzyl alcohol, cyclopentane-1,2-diol, cyclopentane-1,3-diol, cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, ethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol, dimethyl acetamide, N-methyl-2-pyrrolidone, dimethyl carbonate, diethyl carbonate, and diglyme.
Regarding Claims 13-15, Bhavaraju does not explicitly suggest the solvent comprises a greater quantity of a mixture of ethylene glycol and another polar aprotic solvent, and a lesser quantity of a polar aprotic solvent, wherein the polar aprotic solvent comprises dimethylacetamide, N-methyl-2-pyrrolidone (NMP), DMC, DEC, tetraglyme, and diglyme; or that the positive electrolyte comprises 96% ethylene glycol, 2-20 wt% water, and 1-40 wt% NMP.
However, Bhavaraju, concerned with low temperature sodium sulfur batteries (i.e., “room temperature” to 130 °C, see e.g., title, [0013]), suggests the use of various organics solvents (e.g., tetraglyme, n-methyl formamide, and water, [0017]) in the catholyte when the cathode is a sulfur cathode; water is used because it can dissolve lower and higher sodium polysulfides, [0051], and the solvents dissolve sodium salts, thereby supporting the charge/discharge reactions.
Yang, concerned with low temperature (e.g., room temperature, 10-100 °C, [0016, 0029, 0050]) sodium sulfur batteries, appreciates various solvents (i.e., polar, polar aprotic, [0050, 0051, 0069]) in the catholyte including water, formamides, tetraglyme, diglymes, etc., because they remain liquid at the operating temperature range, are capable of conducting sodium ions between electrodes, and are beneficial for suspending dissolved elemental sulfur and sodium polysulfides, [0069].
Chae, concerned with low temperature sodium sulfur batteries (e.g., 98-200 °C, [0039, 0043, 0073]), suggests one or more organic solvents such as ethylene glycol, NMP, formamides, cyclopentane-1,3-diol, cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, diethylene glycol, triethylene glycol, tetraethylene glycol, etc, are useful in the cathode electrolyte solution provided they dissolves sodium salts, and are chemically stable in a battery operating (charge and discharge) condition, thereby maintaining conductivity of the sodium ions stably for a long period, [0043, 0060-0061, 0073].
Relevant to Claims 10-11, it would be obvious to one having ordinary skill in the art the polar organic solvent includes one or more of 1,3- propanediol,1,4-butanediol, dihydroxybenzyl alcohol, cyclopentane-1,2-diol, cyclopentane-1,3-diol, cyclohexane-1,2-diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, ethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol, dimethyl acetamide, N-methyl-2-pyrrolidone, dimethyl carbonate, diethyl carbonate, and diglyme with the expectation of dissolving sodium salt, and because such solvents are chemically stable in a low temperature battery operating (charge and discharge) condition, thereby maintaining conductivity of the sodium ions stably for a long period.
Relevant to Claims 13-15, "It is prima facie obvious to combine two compositions each of which is taught by the prior art to be useful for the same purpose, in order to form a third composition to be used for the very same purpose.... [T]he idea of combining them flows logically from their having been individually taught in the prior art." In re Kerkhoven, 626 F.2d 846, 850, 205 USPQ 1069, 1072 (CCPA 1980). See further, MPEP 2144.06. Bhavaraju, Yang, and Chae suggest solvents (or combination of solvents) appropriate in the catholyte of a low temperature sodium sulfur battery include water, ethylene glycol and NMP. It would be obvious to one having ordinary skill in the art to combine ethylene glycol, NMP and water considering the prior art has recognized their equivalence for the same purpose and in view of their ability to dissolve sodium salts, hence maintain conductivity, in a low temperature sodium sulfur battery environment.
Further, generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). MPEP 2144.05, II., A. In this case, absent evidence of the criticality of the claimed wt% for ethyelene glycol, water, and NMP, the determination of the weight percent of each solvent with respect to the total would be determined through nothing more than routine experimentation to determine the workable range in view of maintaining ionic conductivity of the catholyte.
Claim(s) 20 is rejected under 35 U.S.C. 103 as being unpatentable over Bhavaraju Nakabayashi, Park, and Winn in view of Lloyd et al. (US 2017/0033383, of record), hereinafter Lloyd.
Regarding Claim 20, Bhavaraju does not disclose the first reservoir and the second external reservoir are of a size to hold the respective electrode active materials sufficient for about 1 to about 50 hours of discharge operation of the cell. However, it is well understood in the art, and explained by Lloyd, electrolyte volume, hence tank size/volume, is related to the energy capacity of the battery; specifically, discharge time depends on electrolyte volume (hence tank size/volume) and varies from minutes to days. Depending on the desired application (e.g., small scale vs industrial scale energy needs), the charge/discharge time is small (e.g., minutes) to large (i.e., days), thereby necessitating smaller or larger volumes of electrolyte (hence tanks size) to achieve the desired energy capacity for a particular application. See [0003-0004, 0009] of Lloyd. It would be obvious to one having ordinary skill in the art the first reservoir and the second external reservoir are of a size to hold the respective electrode active materials sufficient for about 1 to about 50 hours of discharge operation of the cell depending on the desired energy capacity/application (e.g., short times (minutes) when a small energy capacity is desired, medium times (hours) when a medium amount of energy capacity is desired, or large times (days) when large energy capacity is desired), as suggested by Lloyd.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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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/ANNA KOROVINA/Examiner, Art Unit 1729
/ULA C RUDDOCK/Supervisory Patent Examiner, Art Unit 1729