Prosecution Insights
Last updated: July 17, 2026
Application No. 18/595,930

METHOD AND SYSTEM FOR DISCHARGING SPENT LITHIUM ION BATTERIES

Final Rejection §103
Filed
Mar 05, 2024
Priority
Mar 07, 2023 — provisional 63/450,560
Examiner
RUTISER, CLAIRE A
Art Unit
1751
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Agr Lithium Inc.
OA Round
4 (Final)
42%
Grant Probability
Moderate
5-6
OA Rounds
1y 1m
Est. Remaining
65%
With Interview

Examiner Intelligence

Grants 42% of resolved cases
42%
Career Allowance Rate
68 granted / 161 resolved
-22.8% vs TC avg
Strong +22% interview lift
Without
With
+22.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 6m
Avg Prosecution
16 currently pending
Career history
214
Total Applications
across all art units

Statute-Specific Performance

§101
7.0%
-33.0% vs TC avg
§103
80.8%
+40.8% vs TC avg
§102
2.8%
-37.2% vs TC avg
§112
3.3%
-36.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 161 resolved cases

Office Action

§103
Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Status of Claims No amendments are made. Claims 14-21, as filed 5 May 2026, are examined herein. Response to Arguments Applicant argues (page 6) that Yao discloses a range from 0.4 to 0.8 mol/L and because Yao states that 0.8 mol/L is better than 0.4 mol/L, that therefore Yao teaches against the use of a lower concentration solution. (Claimed ranges are 0.1 M to about 0.3 M and about 0.1 M to 0.15 M for the first and second cations, respectively.) Applicant argues that Yao states that when the concentration of FeSO4 solution increased from 0.4 mol/L to 0.8 mol/L, the improvement in discharge efficiency is reflected in all three aspects: the discharge rate in the efficient section, the final voltage, and ADT (as shown in Fig. 4c). Applicant argues that therefore Yao teaches that increasing FeSO4 concentration improves performance, and therefore teaches away from testing lower concentration values. This is not persuasive. Examiner notes that Yao discloses 0.4 to 0.8 mol/L of a discharge solution, which may be FeSO4. Zhang in the field of (abstract) discharge solutions discloses at [0006] the use of a reducing agent to provide efficient discharge. Zhang discloses at [0007-0008] multiple candidates for a 2-component discharge solution, those candidates including ferrous sulfate and ferric sulfate, each at a molar ratio of 0.1 M to 5M. At [0007] Zhang discloses ferrous sulfate as a candidate reducing agent, providing safe and efficient discharge. At [0019] Zhang discloses that compared to traditional methods, the discharge termination voltage is lower. In addition to the motivation set forth below, a person of ordinary skill would understand the because the solution is more efficient, the molar ratio can be lower, and would therefore be motivated to optimize using the broader ranges of Zhang, with a reasonable expectation of selecting values falling within the claimed range. The rejection is maintained. Claim Rejections - 35 USC § 103 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claim(s) 14-21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yao (Yao, Lin Peng, et al. "An environmentally friendly discharge technology to pretreat spent lithium-ion batteries." Journal of Cleaner Production 245 (2020): 118820) in view of Zhang (CN 114552044 A, with citations to the provided Espacenet translation) and Horie (US 20230361370 A1). Regarding claim 14, Yao teaches (FIG. 7) a system for discharging a spent Li-ion battery. Yao teaches (FIG. 7) a container comprising an aqueous discharging solution (page 6 col. 2 FeSO4 solution in water, FIG. 4C 0.4 mol/L and 0.8 mol/L as non-limiting examples) but Yao does not explicitly teach the solution comprising an aqueous solution of (multiple) salts and an organic acid, the salts sharing a common anion and having a redox couple as cations; wherein the redox couple comprises a first cation of a metal having a first oxidation state and a second cation of the same metal having a second oxidation state different from the first oxidation state. Zhang discloses [0001] rapid and safe release of residual charge and [0006] a composite electrolyte solution for the safe and efficient discharge of spent lithium-ion batteries, and at [0007] discloses that the inorganic salts (first cation) are soluble in water and may be selected from options including ferric sulfate, and may include a reducing agent, where the candidates include one or more of ferrous sulfate (second cation) and ascorbic acid (an organic acid). At [0038], Example 4 provides support for selection one sulfate salt from the inorganic salt list, in combination with both ferrous sulfate and ascorbic acid from the reducing agent list. A person of ordinary skill in the art would have been motivated, as of before the effective filing date of the instant invention, to replace Yao’s FeSO4 solution with selections from Zhang’s list of inorganic salts and reducing agents, with a reasonable expectation of successfully having rapid and safe release of residual charge. The person of ordinary skill would have been motivated to specifically select Zhang’s ferric sulfate (first cation), ferrous sulfate (second cation), and ascorbic acid (organic acid) to make the discharge solution, as these represent a selection from a finite number of identified, predictable solutions, with a reasonable expectation of success, thus meeting the limitation the salts sharing a common anion and having a redox couple as cations; wherein the redox couple comprises a first cation of a metal having a first oxidation state and a second cation of the same metal having a second oxidation state different from the first oxidation state. Regarding the limitation wherein the aqueous solution comprises a salt with the first cation at a concentration in a range from about 0.1 M to about 0.3 M and a salt with the second cation at a concentration in a range from about 0.1 M to about 0.15 M, Yao at page 2 column 1 contemplates the need to optimize the medium and concentration of the discharge solution, for the purpose of improved efficiency and reduced environmental impact. However, Yao discloses (FIG. 4C, a non-limiting example) ferric sulfate discharge solution at 0.4 and 0.8 mol/L, which is outside of the claimed range. Zhang at [0007] discloses the inorganic salts in a range of 0.1 to 5 M, and the reducing agent also in a range of in a range of 0.1 to 5 M, which encompasses the instant claim limitation. The person of ordinary skill in the art would have been motivated to optimize the discharge solution of modified Yao with the first and second cation concentrations based on the ranges taught by Zhang, in order to balance efficiency and environmental impact, with a reasonable expectation of selecting a value in the overlapping part of the range. Regarding the limitation initiate a contact between external electrodes of the spent Li-ion battery and the discharging solution, and disengage the contact between the external electrodes and the discharging solution when the voltage measured by the voltage sensor across the external electrodes of the spent Li-ion battery being below a threshold voltage, Yao further teaches (FIG. 7) a conveyor belt which initiates and disengages contact between the external electrodes and the discharge solution, however, Yao does not explicitly teach a voltage sensor configured to measure a voltage across external electrodes of the spent Li-ion battery; a controller operably connected to the voltage sensor, and configured to: initiate a contact between external electrodes of the spent Li-ion battery and the discharging solution, and disengage the contact between the external electrodes and the discharging solution when the voltage measured by the voltage sensor across the external electrodes of the spent Li-ion battery being below a threshold voltage. Horie, in the same field of endeavor, discloses (FIG. 2 and ([0057]) a discharging device 12 comprising a control unit 32 and a voltometer 30 (voltage sensor). At FIG. 3 and ([0064-0066]), Horie discloses discharge step S102 and S104 with voltage monitoring, where the discharge process ends when a lower voltage limit is reached. At ([0075]) Horie discloses a 5th embodiment, where two discharge tanks are used to carry out the discharge process. A person of ordinary skill in the art would have been motivated, as of before the effective filing date of the instant invention, to select the control unit and voltage sensor of Horie for use with the conveyor belt and aqueous discharging solution of modified Yao, in order to have the controller monitor voltage and control belt speed, with a reasonable expectation of successfully monitoring the discharge process for safety, and setting a belt speed in the tank such that a battery with a voltage sensor affixed will be efficiently and safely discharged. Regarding claim 15, Yao in view of Zhang and Horie teaches all of the limitations as set forth above. Zhang discloses [0007] ferric sulfate and ferrous sulfate, which create a sulfate anion (a candidate within the scope of the claimed list of alternatives). The motivation to make this selection from Zhang, as set forth in claim 14, is incorporated herein by reference. Regarding claim 16, Yao in view of Zhang and Horie teaches all of the limitations as set forth above. Zhang discloses at [0007] ferric sulfate and ferrous sulfate, (equivalent to Fe2+/Fe3+) which is a candidate within the scope of the claimed list of alternatives. The motivation to make this selection from Zhang, as set forth in claim 14, is incorporated herein by reference. Regarding claim 17, Yao in view of Zhang and Horie teaches all of the limitations as set forth above. Zhang discloses at [0007] discloses an aqueous solution of ferrous sulfate and ferric sulfate. The motivation to make this selection from Zhang, as set forth in claim 14, is incorporated herein by reference. Regarding claim 18, Yao in view of Zhang and Horie teaches all of the limitations as set forth above. Yao further teaches (FIG. 4(c)) the discharge of the batteries wherein the threshold voltage is in a range from about 0.1 V to about 1.5 V. Regarding claim 19, Yao in view of Zhang and Horie teaches all of the limitations as set forth above. Yao further teaches (see FIG. 7) wherein initiating contact between external electrodes of the spent Li-ion battery and the discharging solution comprises immersing the spent Li-ion battery into the container such that external electrodes of the spent Li-ion battery contact the discharging solution, and disengaging the contact between the external electrodes of the spent Li-ion battery comprises removing the spent Li-ion battery from the container such that the external electrodes do not contact the discharging solution. Regarding claim 20, Yao in view of Zhang and Horie teaches all of the limitations as set forth above. Yao teaches (FIG. 7) a conveyer belt and sediment scraper in the discharge solution tank, and the motivation for the conveyor belt to be controlled by the controller, as set forth in claim 14, is incorporated herein by reference. The instant specification at ([0048]) teaches the need for stirring to actively remove evolved gas or deposited materials and teaches that suitable types of stirring include a magnetic stirrer, ultrasound, or a rocker mechanism. A person of ordinary skill in the art would have understood, as of before the effective filing date of the instant invention, that the conveyor belt of Yao would help to remove evolved gas or deposited materials, thus meeting the instant claim limitation (…comprising an ultrasound generator configured to generate ultrasound vibrations and apply the ultrasound vibrations to the discharging solution, wherein the controller is further configured to control the ultrasound generator.) Regarding claim 21, Yao in view of Zhang and Horie teaches all of the limitations as set forth above. Yao page 1 column 2 mentions a Tesla Model S vehicle bursting into flames because of battery damage in a collision. However, Yao does not explicitly teach a temperature regulator operably coupled to the container and configured to maintain the temperature of the discharging solution while the external electrodes are contacted with the discharging solution. A person of ordinary skill in the art would have understood, as of before the effective filing date of the instant invention, that discharging batteries into a discharge tank will increase the temperature of the discharge liquid, and would have understood the importance of monitoring the temperature of the discharge tank, in order to avoid triggering thermal runaway in batteries being recycled, and would have therefore added a cooling system to the discharge solution tank, with a reasonable expectation of reducing the risk of thermal runaway. 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. Any inquiry concerning this communication or earlier communications from the examiner should be directed to CLAIRE A RUTISER whose telephone number is (571)272-1969. The examiner can normally be reached 9:00 AM to 5:00 PM 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, Jonathan Leong can be reached on 571-270-1292. 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. CLAIRE A. RUTISER Examiner Art Unit 1751 /C.A.R./Examiner, Art Unit 1751 /Haroon S. Sheikh/Primary Examiner, Art Unit 1751
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Prosecution Timeline

Show 3 earlier events
Mar 17, 2025
Response Filed
Mar 26, 2025
Final Rejection mailed — §103
Jun 26, 2025
Response after Non-Final Action
Jul 09, 2025
Request for Continued Examination
Jul 14, 2025
Response after Non-Final Action
Nov 05, 2025
Non-Final Rejection mailed — §103
May 05, 2026
Response Filed
Jun 22, 2026
Final Rejection mailed — §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

5-6
Expected OA Rounds
42%
Grant Probability
65%
With Interview (+22.5%)
3y 6m (~1y 1m remaining)
Median Time to Grant
High
PTA Risk
Based on 161 resolved cases by this examiner. Grant probability derived from career allowance rate.

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