Prosecution Insights
Last updated: April 19, 2026
Application No. 17/797,306

METAL AIR BATTERY SYSTEM

Non-Final OA §103
Filed
Aug 03, 2022
Examiner
HARRIS, MARY GRACE
Art Unit
1729
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Mitsubishi Heavy Industries Ltd.
OA Round
3 (Non-Final)
70%
Grant Probability
Favorable
3-4
OA Rounds
3y 3m
To Grant
99%
With Interview

Examiner Intelligence

Grants 70% — above average
70%
Career Allow Rate
130 granted / 187 resolved
+4.5% vs TC avg
Strong +33% interview lift
Without
With
+32.6%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
43 currently pending
Career history
230
Total Applications
across all art units

Statute-Specific Performance

§103
59.3%
+19.3% vs TC avg
§102
19.1%
-20.9% vs TC avg
§112
18.3%
-21.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 187 resolved cases

Office Action

§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 . Response to Amendment Support for the amendments to claims 1 can be found in original claims 6-7. The amendments to the claims have been entered. Response to Arguments Applicant’s arguments, see Remarks Pages 4-5, filed 07/23/2025, with respect to the rejections under 35 U.S.C. 103 have been fully considered. The rejections have been withdrawn in light of the amendments to the claims and Applicant’s arguments. However, upon further consideration and an updated search, a new ground(s) of rejection is made in view of Hopkins et al (US 20190326603 A1) in view of Joboji (JP2010170819A, using the provided machine English translation from Espacenet) in view of Kondo et al (JP2012028017A, as given in the 11/22/2022 IDS) in view of Kuhl (US 4047894 A). 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. Claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over Hopkins et al (US 20190326603 A1) in view of Joboji (JP2010170819A, using the provided machine English translation from Espacenet) in view of Kondo et al (JP2012028017A, as given in the 11/22/2022 IDS) in view of Kuhl (US 4047894 A). Regarding claim 1, Hopkins discloses a metal air battery system (metal-air battery system 120 in Fig. 2; see entire disclosure and especially P38), comprising: a battery device including a negative electrode and a positive electrode, the battery device having a chamber which is defined between the positive electrode and the metal body and through which an electrolytic solution flows (“The metal-air battery 210 may include a metallic anode 212 and an air cathode 214 spaced apart from the metallic anode 212, such that the air cathode 214 and the metallic anode 212 define a gap 216 within the metal-air battery 210. ”, P39; “The fluid circuit 230 may be in fluid communication with the metal-air battery 210, and more specifically, with the gap 216 of the metal-air battery 210. The fluid circuit 230 may generally include one or more of piping, reservoirs, pumps, and combinations thereof, such that the flowable form of the electrolyte 232 and the liquid 234 are movable between the fluid circuit 230 and the gap 216” P44); an electrolytic solution tank storing the electrolytic solution (first reservoir 238 in Fig. 2; see entire disclosure and especially P58); an electrolytic solution supply line connecting the electrolytic solution tank and the chamber (see the line pump 236 sits on in Fig. 2; see entire disclosure and especially P56); an electrolytic solution return line connecting the electrolytic solution tank and the chamber (see the line above the line pump 236 sits on in Fig. 2; see entire disclosure and especially P56); and a pump disposed in the electrolytic solution supply line (pump 236 sits on in Fig. 2; see entire disclosure and especially P56). However, Hopkins does not disclose a metal body electrically connected to the negative electrode, an oxygen separation device for separating oxygen from air, a bubbling device for supplying a gas containing oxygen separated by the oxygen separation device into the electrolytic solution supplied to the chamber while bubbling the gas, and a carbon dioxide removal device for removing carbon dioxide from the gas containing oxygen separated by the oxygen separation device or air supplied to the oxygen separation device, wherein the bubbling device bubbles the gas into the electrolytic solution flowing through the electrolytic solution supply line between the pump and the chamber. In a similar field of endeavor, Joboji teaches an air battery system (1 in Fig. 1) including an oxygen supply device (150 in Fig. 1) disposed after a pump (P in Fig. 1) and before an air battery (100 in Fig. 1; see entire disclosure and especially P19, 23-24). Joboji teaches the oxygen supply device enriches the amount of oxygen in an electrolyte solution flowing to the air battery by bubbling air (or oxygen) or the like (P24). Joboji teaches this suppresses a decrease in output due to insufficient oxygen supply (P24). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have utilized the teaching of Joboji and provided between the pump (236) and battery (210) of Hopkins a bubbling device for supplying a gas containing oxygen separated by the oxygen separation device into the electrolytic solution supplied to the chamber while bubbling the gas, given Joboji teaches this can enrich the amount of oxygen in the electrolyte solution flowing to the battery, thereby suppressing a decrease in output due to insufficient oxygen supply. Hopkins further teaches the negative electrode (metallic anode) can be made of materials such as lithium and materials for supporting the negative electrode (P40). However, modified Hopkins does not meet the limitation a metal body electrically connected to the negative electrode, an oxygen separation device for separating oxygen from air, and a carbon dioxide removal device for removing carbon dioxide from the gas containing oxygen separated by the oxygen separation device or air supplied to the oxygen separation device. In a similar field of endeavor, Kondo teaches a current collector made of a metal plate such as copper foil can be used to hold metallic lithium that constitutes a negative electrode in a metal-air battery (see entire disclosure and especially P12). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have utilized the teaching of Kondo and provided a current collector made of a metal plate to the negative electrode of modified Hopkins (thereby meeting the limitation “a metal body electrically connected to the negative electrode”), given Kondo teaches a current collector made of a metal plate such as copper foil can be used to hold metallic lithium that constitutes a negative electrode in a metal-air battery. Further, Joboji teaches the oxygen supply device can supply either air or oxygen to the electrolyte (P24). Kondo teaches an oxygen supply device can supply air containing oxygen to an electrolyte to increase the concentration of oxygen in the electrolyte (P32). Kondo teaches using air is simple and convenient, but if one chooses to use oxygen only, a separation device can separate the oxygen in the air from the nitrogen so that only the oxygen in the air is supplied to the electrolyte (P29). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have utilized the teaching of Kondo and provided wherein an oxygen separation device for separating oxygen from air is utilized within the system of modified Hopkins, given Kondo teaches this can separate oxygen from the nitrogen in air to allow only oxygen to be supplied to an electrolyte in a metal-air battery system. Hopkins discloses the electrolytic solution can include sodium hydroxide and potassium hydroxide (P47). However, modified Hopkins still does not meet the limitation a carbon dioxide removal device for removing carbon dioxide from the gas containing oxygen separated by the oxygen separation device or air supplied to the oxygen separation device. In a similar field of endeavor, Kuhl teaches metal-air batteries are operated using an alkaline electrolyte, therefore, it is necessary to remove the carbon dioxide from the air used before it is supplied to the air electrode (C1 / L16-21). Kuhl teaches this prevents the electrolytic liquid from being carbonatized and result in impairment or destruction of the metal and air electrodes (C1 / L21-24). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have utilized the teaching of Kuhl and provided to Kondo a carbon dioxide removal device for removing carbon dioxide from the gas containing oxygen separated by the oxygen separation device or air supplied to the oxygen separation device, given Kondo’s gas containing oxygen separated by the oxygen separation device is bubbled into their electrolyte and Kuhl teaches removing carbon dioxide from an air stream to prevent electrolyte from being carbonatized, therefore, preventing impairment or destruction of the metal and air electrodes. Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Hopkins et al (US 20190326603 A1) in view of Joboji (JP2010170819A, using the provided machine English translation from Espacenet) in view of Kondo et al (JP2012028017A, as given in the 11/22/2022 IDS) in view of Kuhl (US 4047894 A) as applied to claim 1, further in view of Miyazawa et al (JP2015072744A, as given in the 11/22/2022 IDS). Regarding claim 2, modified Kondo does not meet the limitation wherein and average value of bubble diameter of the gas supplied into the electrolytic solution by the bubbling device is 100 micron or less. Miyazawa teaches smaller diameter bubbles can increase the residence time of the gas within the electrolyte such that the oxygen utilization rate can be improved (P23). Therefore, one of ordinary skill in the art would recognize that the average value of bubble diameter of the gas supplied into the electrolytic solution is a result-effective variable based upon the desired residence time of the gas within the electrolytic solution, and it would be obvious to one of ordinary skill in the art to select the average value of bubble diameter accordingly. “[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.” See In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). The discovery of an optimum value of a known result effective variable, without producing any new or unexpected results, is within the ambit of a person of ordinary skill in the art. See In re Boesch, 205 USPQ 215 (CCPA 1980) (see MPEP § 2144.05, II.). Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Hopkins et al (US 20190326603 A1) in view of Joboji (JP2010170819A, using the provided machine English translation from Espacenet) in view of Kondo et al (JP2012028017A, as given in the 11/22/2022 IDS) in view of Kuhl (US 4047894 A) as applied to claim 1, further in view of DuFresne et al (US 20170279149 A1). Regarding claim 8, modified Hopkins does not meet the limitation a recovery container communicating with a bottom portion of the electrolytic solution tank. DuFresne teaches a fuel cell system including a reaction product removal system (P43). DuFresne teaches reaction product can precipitate from and/or within an electrolyte and restrict the flow of an electrolyte (P31, 43). DuFresne teaches an outlet conduit configures to convey an outlet stream including precipitate and electrolyte to a separation assembly (P45). DuFresne teaches pump provides the force to send the precipitate and electrolyte to a separation assembly that separates the two (P44). DuFresne teaches the precipitate can then be sent to a recycling system (P46). As seen in Fig. 2, the precipitate falls towards the bottom of a fuel cell housing and therefore the separation assembly is linked to the bottom of the housing. While DuFresne is drawn to a fuel cell while Hopkins is drawn to a metal air battery, if a technique has been used to improve one device (such as provide an outlet stream, separation assembly, and recycling system), and a person of ordinary skill in the art would recognize that it would improve similar devices in the same way (remove precipitate hindering flow of electrolyte), using the technique is obvious unless its actual application is beyond his or her skill. SEE MPEP § 2141 (III) Rationale C, KSR v. Teleflex (Supreme Court 2007). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have utilized the teaching of DuFresne and provided a recovery container communicating with a bottom portion of the electrolytic solution tank, such as the outlet stream, separation assembly, and recycling system of DuFresne, to Hopkins, given DuFresne teaches this allows precipitate to be removed from electrolyte so it does not restrict electrolyte flow. Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Hopkins et al (US 20190326603 A1) in view of Joboji (JP2010170819A, using the provided machine English translation from Espacenet) in view of Kondo et al (JP2012028017A, as given in the 11/22/2022 IDS) in view of Kuhl (US 4047894 A) as applied to claim 1, further in view of Aizawa (JP2011253789A, as given in the 11/22/2022 IDS). Regarding claim 9, modified Hopkins does not disclose wherein the battery device has a cylindrical shape with the metal body surrounding the positive electrode. In a similar field of endeavor, Aizawa teaches a metal air battery (1 in Figs. 1-2) having a cylindrical shape (P19). Aizawa teaches the negative electrode (3 in Figs. 1-2) includes a cylindrical negative electrode current collector (31 in Figs. 1-2) and a cylindrical negative electrode conductive portion (32 in Figs. 1-2, P24). Aizawa also teaches the positive electrode is of a cylindrical shape (2 in Figs. 1-2, P20). Therefore, it would have been obvious before the effective filing date of the claimed invention to have utilized the teaching of Aizawa and changed the form/shape of the battery device of modified Hopkins such that it has a cylindrical shape with the metal body surrounding the positive electrode in order to, for example, provide the metal air battery in a battery tray that only supports cylindrical battery cells, given it is a known configuration/shape for a metal air battery and the change in form or shape, without any new or unexpected results, is an obvious engineering design. See In re Dailey, 149 USPQ 47 (CCPA 1976) (see MPEP § 2144.04). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to Mary Byram whose telephone number is (571)272-0690. The examiner can normally be reached M-F 8 am-5 pm EST. 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, Ula Ruddock can be reached at (571)272-1481. 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. /MARY GRACE BYRAM/Examiner, Art Unit 1729
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Prosecution Timeline

Aug 03, 2022
Application Filed
Jan 06, 2025
Non-Final Rejection — §103
Apr 10, 2025
Response Filed
Apr 21, 2025
Non-Final Rejection — §103
Jul 23, 2025
Response Filed
Nov 03, 2025
Non-Final Rejection — §103 (current)

Precedent Cases

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
70%
Grant Probability
99%
With Interview (+32.6%)
3y 3m
Median Time to Grant
High
PTA Risk
Based on 187 resolved cases by this examiner. Grant probability derived from career allow rate.

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