Prosecution Insights
Last updated: April 19, 2026
Application No. 18/078,167

IMPROVED LEAD ACID BATTERY SEPARATORS, BATTERIES AND RELATED METHODS

Non-Final OA §103
Filed
Dec 09, 2022
Examiner
THOMAS, BRENT C
Art Unit
1724
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Daramic LLC
OA Round
7 (Non-Final)
50%
Grant Probability
Moderate
7-8
OA Rounds
3y 10m
To Grant
76%
With Interview

Examiner Intelligence

Grants 50% of resolved cases
50%
Career Allow Rate
215 granted / 434 resolved
-15.5% vs TC avg
Strong +26% interview lift
Without
With
+26.4%
Interview Lift
resolved cases with interview
Typical timeline
3y 10m
Avg Prosecution
25 currently pending
Career history
459
Total Applications
across all art units

Statute-Specific Performance

§101
0.2%
-39.8% vs TC avg
§103
66.0%
+26.0% vs TC avg
§102
18.6%
-21.4% vs TC avg
§112
9.3%
-30.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 434 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application is being examined under the pre-AIA first to invent provisions. Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 12/11/2025 has been entered. Response to Arguments Applicant’s arguments, see pages 5-6, filed 12/11/2025, with respect to the rejection(s) of amened claim(s) 15 under Weerts et al (US 2002/0004166 A1, hereafter Weerts) in view of Pleis (US 1,362,737, hereafter Pleis), in view of La et al. (US 2011/0045339 A1, hereafter La), in view of Nagamatsu et al. (US 2009/0030100 hereafter Nagamatsu), in view of Palmer et al. (US 3,847,676, hereafter Palmer), in view of Whear et al. (US 6,120,939, hereafter Whear ‘939), Bauer et al. (CN 1331843, hereafter Bauer), further in view of Rajaram et al (US 2011/0287324 A1, hereafter Rajaram) have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Weerts et al (US 2002/0004166 A1, hereafter Weerts) in view of Pleis (US 1,362,737, hereafter Pleis), in view of La et al. (US 2011/0045339 A1, hereafter La), in view of Nagamatsu et al. (US 2009/0030100 hereafter Nagamatsu), in view of Palmer et al. (US 3,847,676, hereafter Palmer), in view of Whear et al. (US 6,120,939, hereafter Whear ‘939), Bauer et al. (CN 1331843, hereafter Bauer), in view of Rajaram et al (US 2011/0287324 A1, hereafter Rajaram), in view of Whear et al. (US 2008/0299462 A1, hereafter Whear ‘462), and further in view of the new prior art of Mittal et al. (WO 2010058240 A1, hereafter Mittal). Mittal is relied upon for teaching the use of surfactants to lower water loss as detailed in the claim rejections below. Applicant's arguments filed 12/11/2025 have been fully considered but they are not persuasive. The arguments are presented on pages 7-8 that one of ordinary skill in the art would not use the stiffening material coating of Whear ‘462 with the separator of modified Weerts since it would excessively increase the basis weight. These arguments are not found persuasive due to the fact that the cited 50-100 g/m2 value is only cited for a typical coating applied to a glass mat [0026]. Whear ‘462 teaches only coating the ribs of a separator or coating in a pattern which would reduce added basis weight and teaches a coating weight applied to a separator of only 5-10 g/m2 [0013-0014, 0026]. When added to the 100 to 200 g/m2 taught by Rajaram [0057] this would still overlap and render the claimed range obvious. 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. Claims 15, 17, 19-20, 22-24, and 26-27 is/are rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Weerts et al (US 2002/0004166 A1, hereafter Weerts) in view of Pleis (US 1,362,737, hereafter Pleis), in view of La et al. (US 2011/0045339 A1, hereafter La), in view of Nagamatsu et al. (US 2009/0030100 hereafter Nagamatsu), in view of Mittal et al. (WO 2010058240 A1, hereafter Mittal), in view of Whear et al. (US 6,120,939, hereafter Whear ‘939), Bauer et al. (CN 1331843, hereafter Bauer), in view of Rajaram et al (US 2011/0287324 A1, hereafter Rajaram), and further in view of Whear et al. (US 2008/0299462 A1, hereafter Whear ‘462). With regard to claims 15, 17, 19-20, 22-24 and 26 Weerts teaches a separator for a lead acid battery (claim 17, claim 23) having a front (with major ribs) face facing a positive electrode and a reverse face facing a negative electrode (opposite the face with major ribs) [0001, 0004, 0018], the separator consisting of: a microporous polyethylene (claim 26) membrane having a backweb with integral ribs, wherein said ribs consist of integral ribs on the front face (longitudinal major and mini ribs 20 and 30) that would run parallel to buoyant forces (parallel to longitudinal edges which would be parallel to buoyant forces when the battery is upright) and integral negative cross ribs spaced apart and running across the reverse face (micro ribs 40) [0004, 0018-0019, 0021, 0031, 0035, fig. 4]; Weerts teaches that the micro ribs may be disposed at an angle [0031] but does not explicitly teach that they are perpendicular to the longitudinal ribs (which would be perpendicular to buoyant forces). However, in the same field of endeavor Pleis teaches the use of ribs at right angles on opposite faces of a separator [col. 1 line 45-col. 2 line 2, fig. 1]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the perpendicular orientation of Pleis with the micro ribs of Weerts for the benefits of resisting breakage of the ribs and making the separator strong and light [Pleis col. 1 line 45-col. 2 line 2]. Weerts teaches the use of a microporous polyethylene material [0035] but does not explicitly teach the use of a microporous silica filled polyethylene membrane or a processing oil. However, in the same field of endeavor La teaches the use of a separator material comprising polyethylene, silica (a filler), and a process oil [0025]. La further teaches that the material is oxidation resistant and teaches that oxidation resistance is a desirable property [0008-0009]. Therefore, even if the material of La did not exhibit the claimed values inherently one of ordinary skill in the art would find it obvious to optimize the oxidation resistance based on the teachings of La [0008-0009]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the separator material of La with the separator of Weerts for the benefit of its oxidation resistance and high strength [La 0009]. Weerts and La teach the separator material as detailed above, but do not explicitly disclose the claimed electrical resistance. However, since Weerts and La teach a substantially similar material (microporous silica filled polyethylene membrane) it would exhibit the claimed properties. Weerts does not explicitly teach the claimed puncture resistance. However, in the same field of endeavor, Whear ‘939 teaches a puncture resistance of more than 8 N is desirable (which would overlap and render obvious the claimed range, see MPEP 2144.05) [col. 6 lines 17-24]. It would have been obvious to one of ordinary skill in the art to use the puncture resistance of Whear ‘939 with the separator of modified Weerts since it is known to be effective in a battery separator [Whear ‘939 col. 6 lines 17-24]. Weerts does not explicitly teach the use of a surfactant or the claimed water loss. However, in the same field of endeavor, Mittal teaches the use of surfactants with separators and teaches the use of additives in addition to surfactants to optimize reducing water loss (which would render the claimed values obvious) [pg. 8 lines 14-18]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the surfactants of and additives of Mittal with the separator of modified Weerts for the benefit of a substantial reduction in the rate of water loss [Mittal pg. 8 lines 1-4]. Weerts and La teach the separator material as detailed above but do not explicitly disclose having an Acid Leachable Total Organic Carbon value less than 100 ppm (claim 15), less than 75 ppm (claim 20), nor less than 50 ppm (claim 19). However, this property would be based on the separator composition. Since Weerts and La teach a substantially similar material (microporous silica filled polyethylene membrane) it would exhibit the claimed properties. Furthermore, in the same field of endeavor (battery separator materials) Nagamatsu teaches minimizing acid insoluble impurities including carbon below 150 ppm or less (which would render obvious the claimed ranges of claims 15, 19, and 20) [0088]. Based on the teachings of Nagamatsu one of ordinary skill in the art would find it obvious to minimize carbon amounts for the benefit of avoiding conductive impurities that may cause short circuits in a battery separator [Nagamatsu 0088]. Weerts does not explicitly teach bio-mineral fillers. However, in the same field of endeavor, Bauer teaches the use of hydroxyapatite (a bio-mineral) fillers in battery separators [Bauer machine translation page 4, paragraphs 3-4]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the hydroxyapatite (bio-mineral) of Bauer with the separator of modified Weerts since it is known to be effective in separators with high temperature resistance and mechanical stability [Bauer machine translation page 3 paragraph 4-page 4 paragraph 4]. Weerts does not explicitly teach the claimed thickness or basis weight. However, in the same field of endeavor, Rajaram teaches the use of a lead acid battery separator with a thickness of 100 microns or greater (which overlaps and renders obvious the claimed ranges of claims 15, 22, and 24) [0058] and a basis weight of between 100 to 200 gsm (which overlaps and renders obvious the claimed range) [0057]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the thickness of Rajaram with the separator of Weerts since it is known to be effective in a lead acid battery [0002, 0057-0058]. Modified Weerts teaches reverse face ribs spaced apart (micro ribs 40) [0004, 0018-0019, 0021, 0031, 0035, fig. 4] but does not explicitly teach the claimed stiffness. However, in the same field of endeavor, Whear ‘462 teaches a similar material (microporous polyethylene with ribs) with a glass fiber mat can have a stiffness of 1401 mN in the CMD direction and further teaches the use of a stiffening material to provide a stiffness of 2766 mN in a CMD direction (which falls within and anticipates the claimed range) [0011-0015]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the stiffening material and corresponding stiffness of Whear ‘462 with the separator of modified Weerts for the benefit of enhanced stiffness without hindering ionic flow [Whear ‘462 0013]. The limitations regarding the lead acid battery being an idle start stop battery are considered intended use since they would not further limit the structure of the claimed separator. While intended use recitations and other types of functional language cannot be entirely disregarded. However, in apparatus, article, and composition claims, intended use must result in a structural difference between the claimed invention and the prior art in order to patentably distinguish the claimed invention from the prior art. If the prior art structure is capable of performing the intended use, then it meets the claim. In a claim drawn to a process of making, the intended use must result in a manipulative difference as compared to the prior art. In re Casey, 370 F.2d 576, 152 USPQ 235 (CCPA 1967); In re Otto, 312 F.2d 937, 938, 136 USPQ 458, 459 (CCPA 1963). With regard to claim 17, Weerts teaches in a lead acid battery, the improvement comprising the separator of claim 15 (separator for use in a lead-acid battery) [0001, 0010]. With regard to claim 23, Weerts teaches the use of the separator in a battery [0001, 0010]. With regard to claim 27, Weerts does not explicitly teach the use of a glass mat. However, in the same field of endeavor, Whear ‘462 teaches the use of a glass fiber mat [0017]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the glass fiber mat of Whear ‘462 with the separator of Weerts for the benefit of increased stiffness [Whear ‘462 0017]. Claim 18 is rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Weerts, Pleis, La, Rajaram, Whear ‘939, Bauer, Mittal, and Whear ‘462 as applied to claims 15, 17, 19-20, 22-24, and 26-27 above, and further in view of Hottori et al. (US 6,492,059 B1, hereafter Hottori). With regard to claim 18, Weerts teaches the improvement comprising the lead acid battery of claim 17, but does not explicitly disclose that it is located within a vehicle. However, in the same field of endeavor, Hottori teaches a lead-acid battery separator for use in a car or electric vehicle [col. 3, lines 4-12]. It would have been obvious to a person of ordinary skill in the art at the time of the invention to use the lead-acid battery separator of Weerts in a battery for the car or electric vehicle of Hottori for the benefit of powering motors or accessories within the vehicle. Claim 30 is rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Weerts, Pleis, La, Rajaram, Whear ‘939, Bauer, Mittal, and Whear ‘462 as applied to claims 15, 17, 19-20, 22-24, and 26-27 above, and further in view of Aasen (GB 524,421, hereafter Aasen). With regard to claim 30, modified Weerts does not explicitly teach the use of fish meal as a filler. However, in a field of endeavor relevant to the problem solved, Aasen teaches the use of fish meal as a filler in thermoplastic materials [line 42-line 61]. It would have been obvious to one of ordinary skill in the art to use the fish meal of Aasen with the separator of modified Weerts since it is taught to contain skin and bones that are effective fillers in thermoplastic materials that are workable and able to be hardened in molds [Aasen line 42-line 61]. Claims 31 is/are rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Weerts et al (US 2002/0004166 A1, hereafter Weerts) in view of Pleis (US 1,362,737, hereafter Pleis), in view of La et al. (US 2011/0045339 A1, hereafter La), in view of Palmer et al. (US 3,847,676, hereafter Palmer), in view of Whear et al. (US 6,120,939, hereafter Whear ‘939), in view of Bauer et al. (CN 1331843, hereafter Bauer), and further in view of Whear et al. (US 2008/0299462 A1, hereafter Whear ‘462). With regard to claim 31, Weerts teaches a separator for a lead acid battery (claim 17, claim 23) having a front (with major ribs) face facing a positive electrode and a reverse face facing a negative electrode (opposite the face with major ribs) [0001, 0004, 0018], the separator consisting of: a microporous polyethylene (claim 26) membrane having a backweb with integral ribs, wherein said ribs consist of integral ribs on the front face (longitudinal major and mini ribs 20 and 30) that would run parallel to buoyant forces (parallel to longitudinal edges which would be parallel to buoyant forces when the battery is upright) and integral negative cross ribs spaced apart and running across the reverse face (micro ribs 40) [0004, 0018-0019, 0021, 0031, 0035, fig. 4]; Weerts teaches that the micro ribs may be disposed at an angle [0031] but does not explicitly teach that they are perpendicular to the longitudinal ribs (which would be perpendicular to buoyant forces). However, in the same field of endeavor Pleis teaches the use of ribs at right angles on opposite faces of a separator [col. 1 line 45-col. 2 line 2, fig. 1]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the perpendicular orientation of Pleis with the micro ribs of Weerts for the benefits of resisting breakage of the ribs and making the separator strong and light [Pleis col. 1 line 45-col. 2 line 2]. Weerts teaches the use of a microporous polyethylene material [0035] but does not explicitly teach the use of a microporous silica filled polyethylene membrane or a processing oil. However, in the same field of endeavor La teaches the use of a separator material comprising polyethylene, silica (a filler), and a process oil [0025]. La further teaches that the material is oxidation resistant and teaches that oxidation resistance is a desirable property [0008-0009]. Therefore, even if the material of La did not exhibit the claimed values inherently one of ordinary skill in the art would find it obvious to optimize the oxidation resistance based on the teachings of La [0008-0009]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the separator material of La with the separator of Weerts for the benefit of its oxidation resistance and high strength [La 0009]. Weerts does not explicitly teach the use of a surfactant. However, in the same field of endeavor, Palmer teaches the use of mixtures of ionic and non-ionic surfactants with separators [col. 6 lines 25-49]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the surfactants of Palmer with the separator of modified Weerts for the benefit of increasing the wettability of the separator with acids which improves separator performance [col. 1 lines 9-12, col. 6 lines 25-49]. Weerts does not explicitly teach bio-mineral fillers. However, in the same field of endeavor, Bauer teaches the use of hydroxyapatite (a bio-mineral) fillers in battery separators [Bauer machine translation page 4, paragraphs 3-4]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the hydroxyapatite (bio-mineral) of Bauer with the separator of modified Weerts since it is known to be effective in separators with high temperature resistance and mechanical stability [Bauer machine translation page 3 paragraph 4-page 4 paragraph 4]. Weerts does not explicitly teach the claimed puncture resistance. However, in the same field of endeavor, Whear ‘939 teaches a puncture resistance of more than 8 N is desirable (which would overlap and render obvious the claimed range, see MPEP 2144.05) [col. 6 lines 17-24]. It would have been obvious to one of ordinary skill in the art to use the puncture resistance of Whear ‘939 with the separator of modified Weerts since it is known to be effective in a battery separator [Whear ‘939 col. 6 lines 17-24]. Modified Weerts teaches reverse face ribs spaced apart (micro ribs 40) [0004, 0018-0019, 0021, 0031, 0035, fig. 4] but does not explicitly teach the claimed stiffness. However, in the same field of endeavor, Whear ‘462 teaches a similar material (microporous polyethylene with ribs) with a glass fiber mat can have a stiffness of 1401 mN in the CMD direction and further teaches the use of a stiffening material to provide a stiffness of 2766 mN in a CMD direction (which falls within and anticipates the claimed range) [0011-0015]. It would have been obvious to one of ordinary skill in the art at the time the invention was made to use the stiffening material and corresponding stiffness of Whear ‘462 with the separator of modified Weerts for the benefit of enhanced stiffness without hindering ionic flow [Whear ‘462 0013]. The limitations regarding the lead acid battery being an idle start stop battery are considered intended use since they would not further limit the structure of the claimed separator. While intended use recitations and other types of functional language cannot be entirely disregarded. However, in apparatus, article, and composition claims, intended use must result in a structural difference between the claimed invention and the prior art in order to patentably distinguish the claimed invention from the prior art. If the prior art structure is capable of performing the intended use, then it meets the claim. In a claim drawn to a process of making, the intended use must result in a manipulative difference as compared to the prior art. In re Casey, 370 F.2d 576, 152 USPQ 235 (CCPA 1967); In re Otto, 312 F.2d 937, 938, 136 USPQ 458, 459 (CCPA 1963). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to BRENT C THOMAS whose telephone number is (571)270-7737. The examiner can normally be reached Flexible schedule, typical hours 11-7 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, Miriam Stagg can be reached at (571)270-5256. 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. /BRENT C THOMAS/Examiner, Art Unit 1724 /MIRIAM STAGG/Supervisory Patent Examiner, Art Unit 1724
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Prosecution Timeline

Dec 09, 2022
Application Filed
Apr 22, 2023
Non-Final Rejection — §103
Aug 25, 2023
Response Filed
Dec 02, 2023
Final Rejection — §103
Jan 23, 2024
Response after Non-Final Action
Feb 05, 2024
Response after Non-Final Action
Feb 22, 2024
Request for Continued Examination
Feb 24, 2024
Response after Non-Final Action
Mar 15, 2024
Non-Final Rejection — §103
Jul 22, 2024
Response Filed
Oct 10, 2024
Final Rejection — §103
Dec 17, 2024
Response after Non-Final Action
Dec 31, 2024
Response after Non-Final Action
Jan 13, 2025
Response after Non-Final Action
Jan 13, 2025
Request for Continued Examination
Jan 15, 2025
Response after Non-Final Action
Jan 25, 2025
Non-Final Rejection — §103
Apr 30, 2025
Response Filed
Aug 09, 2025
Final Rejection — §103
Oct 20, 2025
Response after Non-Final Action
Dec 11, 2025
Request for Continued Examination
Dec 18, 2025
Response after Non-Final Action
Jan 24, 2026
Non-Final Rejection — §103 (current)

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

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Prosecution Projections

7-8
Expected OA Rounds
50%
Grant Probability
76%
With Interview (+26.4%)
3y 10m
Median Time to Grant
High
PTA Risk
Based on 434 resolved cases by this examiner. Grant probability derived from career allow rate.

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