SEPARATOR FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY COMPRISING SAME
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 .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 11/24/2025 has been entered.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 12/22/2025 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Response to Amendment
In response to communication filed on 11/24/2025:
Claim 1 has been amended; no new matter has been entered.
Previous rejections under 35 USC 103 have been upheld.
Response to Arguments
Applicant's arguments filed 11/24/2025 have been fully considered but they are not persuasive.
The Applicant discloses: “Honda discloses that the proportion of the thickener (e.g., PVP) with respect to the total amount of the resin particles, inorganic filler, and thickener is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less. ¶[0018] and [0119]. However, Honda does not disclose the heat resistant binder polymer is present in an amount of 7 parts to 11 parts by weight based on a total weight of the porous coating layer, as required by claim 1. In this regard, the mass% values in Honda are based on a total amount of the resin particles, inorganic filler, and thickener, as discussed above. Claim 1 requires 7 parts to 11 parts by weight based on a total weight of the porous coating layer. In other words, the denominator in the mass% value in Honda, i.e., a total amount of the resin particles, inorganic filler, and thickness, is not necessarily the same as in claim 1, i.e., the porous coating layer.
The Examiner respectfully traverses. Honda discloses the heat resistant porous layer comprises resin particles (which addresses the fluoride binder being that they can comprise PVDF according to paragraph 0099) in an amount of 0.5-30% by mass of the porous layer (Paragraph 0107). Further, the heat resistant porous layer comprises inorganic filler at 65-99% by mass of the total amount of resin particles and inorganic fillers (Paragraph 0115). Finally, the heat resistant porous layer can comprise thickener (which addresses the heat resistant binder polymer) at 10% by mass or less of the total amount of resin particles, inorganic filler, and thickener. These three components make up the total contents of the heat resistant porous layer which read on claim 1. The Applicant still makes the argument that these are different but provides no reasoning as to why.
The Applicant discloses: “Similar arguments apply to the claimed weight ratio, R, of the flame-resistant particles to the heat resistant binder polymer, as argued in the August 25, 2025 Amendment. In the Response to Arguments, the Examiner asserts that "Applicant provided no explanation as to how the weight bases in Honda are different than in claim 1". However, Honda discloses the inorganic filler from 65% by mass to 99% by mass of the total amount of resin particles and inorganic fillers, and the thickener from 10% by mass or less with respect to the total amount of the resin particles, inorganic filler, and thickener, ¶[0115] and [0119]. Claim 1 requires a weight ratio, R, of a weight of the flame-resistant particles in the porous coating layer to a weight of the heat resistant binder polymer in the porous coating layer satisfies Formula 1 (5 < R < 10), as required by claim 1. As argued in the August 25 Amendment, the weight basis (i.e., denominator) in Honda is different than in the claimed weight ratio R and therefore the Examiner's derived R values in Honda do not correspond to the claimed weight ratio R.”
The Examiner respectfully traverses. The Applicant still provides no explanation as to how the weight bases are different. However, Honda discloses the heat resistant porous layer comprises resin particles (which addresses the fluoride binder being that they can comprise PVDF according to paragraph 0099) in an amount of 0.5-30% by mass of the porous layer (Paragraph 0107). Further, the heat resistant porous layer comprises inorganic filler at 65-99% by mass of the total amount of resin particles and inorganic fillers (Paragraph 0115). Finally, the heat resistant porous layer can comprise thickener (which addresses the heat resistant binder polymer) at 10% by mass or less of the total amount of resin particles, inorganic filler, and thickener. These three components make up the total contents of the heat resistant porous layer which read on claim 1.
Finally, with the content limitations of the components of the heat-resistant porous layer provided by Honda and listed above, one of ordinary skill in the art can still determine that Honda reads on the claim. As Applicant correctly states, Honda discloses the inorganic filler from 65% by mass to 99% by mass of the total amount of resin particles and inorganic fillers, and the thickener from 10% by mass or less with respect to the total amount of the resin particles, inorganic filler, and thickener. Assuming 10% by mass of PVP is used, this means that 90% of the remaining components of the porous layer must comprise mass% of both filler and resin. Therefore, the mass % ranges of filler and resin are 58.5-89.1 mass% (90 x [65-99%]) and 0.9-31.5 (90-[58.5, 89.1]) mass% respectively. The R value can now range from 1.9 to 99.
The Applicant discloses: “In any case, any alleged prima facie case of obviousness has been rebutted since the claimed amount of heat resistant binder polymer and weight ratio R produce unexpected results. As argued in the August 25 Amendment, all of the Inventive Examples in the specification (Examples 1-3) have an amount of heat resistant binder polymer and a weight ratio R within the claimed range, while Comparative Examples 1-4 do not, i.e., they have an amount of heat resistant binder polymer and a weight ratio R outside the claimed range. See Table 1. As seen in Table 1, Examples 1-3 had superior air permeation time, heat shrinkage, and/or fracture property, as compared to Comparative Examples 1-4. The claimed K-value (120 or more) also produces unexpected results in terms of heat shrinkage based on the comparison of Example 2 and Comparative Examples 5 and 6 in Table 2.”
The Examiner respectfully traverses. There is only one data point for R<5. This is not sufficient enough to present unexpected results.
MPEP 716.02(d) Unexpected Results Commensurate in Scope With Claimed Invention
II. DEMONSTRATING CRITICALITY OF A CLAIMED RANGE
To establish unexpected results over a claimed range, applicants should compare a sufficient number of tests both inside and outside the claimed range to show the criticality of the claimed range. In re Hill, 284 F.2d 955, 128 USPQ 197 (CCPA 1960).
The Applicant discloses: “Honda does not disclose or even contemplate these unexpected results. Indeed, the preferred ranges of the thickener in Honda, 5% by mass or less and 3% by mass or less, are outside the proposed claimed range and correspond to Comparative Examples 3 and 2, respectively, which are shown in Table 1 to be inferior.”
The Examiner respectfully traverses. Honda et al. still disclose the addition of thickener (PVP) in the amount of 10% by mass or less. This still reads on the claimed limitation.
New grounds of rejection under 35 USC 103 have been introduced in addition to the original grounds of rejection.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-13 are rejected under 35 U.S.C. 103 as being unpatentable over Honda et al. (US 2015/0263325 A1) and further in view of Matsumoto et al. (US 2014/0045031 A1).
Regarding claims 1-3, 5-7, 10, and 12, Honda et al. a separator for a lithium secondary battery (Abstract), comprising: a porous polymer substrate (Abstract and paragraph 0030 disclose a porous substrate having a thermoplastic resin.); and
a porous coating layer on at least one surface of the porous polymer substrate (Abstract discloses a heat resistant porous layer provided on or both sides of the porous substrate.), wherein the porous coating layer comprises flame-resistant particles (Paragraphs 0096-0097 disclose the heat resistant porous layer can comprise inorganic fillers. Further, paragraphs 0108-0109 disclose the inorganic fillers can comprise metal hydroxides such as Mg(OH)2, Ca(OH)2, or Al(OH)3.), a heat resistant binder polymer (Paragraphs 0116-0118 discloses the heat resistant porous layer can also include a thickener such as polyvinyl pyrrolidine.) and a fluorine-containing binder polymer (Paragraphs 0098-0105 discloses the heat resistant porous layer can comprise resin particles such as PVDF.),
wherein a weight ratio, R, of the flame-resistant particles to the heat resistant binder polymer satisfies Formula 1, and
wherein an amount of fluorine-containing binder polymer is larger than an amount of the heat resistant binder polymer:
[Formula 1]
5<R≤10 (Paragraphs 0115 and 0119 discloses the inorganic fillers, such as the as-claimed metal hydroxides, comprise 65-99 wt.% and the thickener, such as PVP, can comprise 3-10 wt.%. In addition, Honda discloses the inorganic filler from 65% by mass to 99% by mass of the total amount of resin particles and inorganic fillers, and the thickener from 10% by mass or less with respect to the total amount of the resin particles, inorganic filler, and thickener. Assuming 10% by mass of PVP is used, this means that 90% of the remaining components of the porous layer must comprise mass% of both filler and resin. Therefore, the mass % ranges of filler and resin are 58.5-89.1 mass% (90 x [65-99%]) and 0.9-31.5 (90-[58.5, 89.1]) mass% respectively. The R value can now range from 1.9 to 99, which reads on the claim.),
wherein the heat resistant binder polymer is present in an amount of 7 parts to 11 parts by weight based on a total weight of the porous coating layer (Paragraph 0119 discloses the thickener, PVP, can be present in the heat resistant binder at 10% by mass or less.).
However, Honda et al. do not teach wherein the flame-resistant particles have an endothermic reaction temperature at 150 °C to 250 °C.
Honda et al. disclose the same flame-resistant particles as the claimed invention and therefore cannot have mutually exclusive properties.
MPEP 2112.01 Composition, Product, and Apparatus Claims
II. COMPOSITION CLAIMS — IF THE COMPOSITION IS PHYSICALLY THE SAME, IT MUST HAVE THE SAME PROPERTIES
"Products of identical chemical composition cannot have mutually exclusive properties." In re Spada, 911 F.2d 705, 709, 15 USPQ2d 1655, 1658 (Fed. Cir. 1990). A chemical composition and its properties are inseparable. Therefore, if the prior art teaches the identical chemical structure, the properties applicant discloses and/or claims are necessarily present.
However, Honda et al. do not teach wherein the heat resistant binder polymer has a K-value of 120 or more and a glass transition temperature of 100°C or higher.
Matsumoto et al. disclose a separator comprising a heat resistant porous film (Abstract) for a secondary battery. Further, the film can comprise fine particles and a binder comprising polyvinyl pyrrolidine (PVP) (Paragraphs 0022, 0028, 0037, and 120). Matsumoto further discloses that the PVP preferably has an average molecular weight of 1,500,000 or more (Paragraph 0032). Finally, organic binder PVP has a K-value of 120, a molecular weight of 3,500,000, and a glass transition temperature of 176 °C (Paragraph 0138; Example 1).
Therefore, it would have been obvious to one of ordinary skill in the art to modify the PVP of Honda with that of Matsumoto in order for the battery being able to retain a high capacity while improving the overall safety of the battery.
Regarding claims 4 and 13, the combination of Honda and Matsumoto et al. teach the separator for the lithium secondary battery according to claim 1. Further, Honda et al. teach wherein the weight ratio of the heat resistant binder polymer to the fluorine containing binder polymer is 20:80 to 40:60 (Paragraph 0119 discloses the PVP, or thickener is at most 10 wt.% whereas paragraph 0105 discloses PVDF is about most 30 wt.% which is within the claimed range.).
Regarding claim 8, the combination of Honda and Matsumoto et al. teach the separator for the lithium secondary battery according to claim 1. Further, Honda et al. teach wherein the separator has a thickness of from 2 µm to 10 µm (Paragraph 0223 discloses a total thickness from 1 to 10 µm.).
Regarding claim 9, the combination of Honda and Matsumoto et al. teach the separator for the lithium secondary battery according to claim 1. Further, Honda et al. teach a heat shrinkage ≤ 25% wherein the heat shrinkage is calculated by measuring a change in length in a machine direction (MD) and a transverse direction (TD) and using the formula of (initial length - length after heat shrinking at 150°C for 30 minutes)/(initial length) X 100 (Paragraph 0143-0144 disclose the separator according to the first embodiment is subjected to a heat treatment at 150°C for 30 minutes, the thermal shrinkage ratio of the separator according to the first embodiment in both the MD direction and the TD direction is preferably 3% or less, and more preferably 2% or less. When the thermal shrinkage ratio is in this range, the shape stability of a separator is high, thereby providing a battery in which a short circuit is less likely to occur even when exposed to high temperatures.). However, they do not teach a rate of increase in air permeation time ≤ 500%, a temperature at break ≥ 300°C, or a fracture area ≤ 10 mm2.
MPEP 2112.01 Composition, Product, and Apparatus Claims
I. PRODUCT AND APPARATUS CLAIMS — WHEN THE STRUCTURE RECITED IN THE REFERENCE IS SUBSTANTIALLY IDENTICAL TO THAT OF THE CLAIMS, CLAIMED PROPERTIES OR FUNCTIONS ARE PRESUMED TO BE INHERENT
Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977).
Regarding claim 11, Honda and Matsumoto et al. teach a lithium secondary battery, comprising: a cathode, an anode, and a separator interposed between the cathode and the anode, wherein the separator is the same as defined in claim 1 (Honda: claim 20; Matsumoto: claim 10).
Claims 1-8 and 10-13 are rejected under 35 U.S.C. 103 as being unpatentable over Sano et al. (JP 2011/124177 A) and further in view of Gu et al. (KR 10-2018-0116008 A) and further in view of Sung et al. (KR 10-2020-0056337 A).
Regarding claims 1-3, 5-7, 10, and 12, Sano et al. a separator for a lithium secondary battery (Abstract), comprising: a porous polymer substrate (Abstract and paragraph 0030 disclose a polyolefin microporous membrane.); and
a porous coating layer on at least one surface of the porous polymer substrate (Abstract discloses a heat resistant porous layer provided on or both sides of the porous substrate.), wherein the porous coating layer comprises flame-resistant particles (Paragraphs 0052-0053 disclose the heat resistant porous layer can comprise inorganic fillers such as metal hydroxides Mg(OH)2, Ca(OH)2, or Al(OH)3.), a heat resistant binder polymer (Paragraph 0058 discloses the heat resistant porous layer can also include a heat resistant resin.) wherein the flame-resistant particles have an endothermic reaction temperature at 150 °C to 250 °C (Paragraph 0053 discloses the endothermic reaction occurs in the range of 200-400 °C.)
wherein a weight ratio, R, of the flame-resistant particles to the heat resistant binder polymer satisfies Formula 1, and
[Formula 1]
5<R≤10 (Paragraph 0056 discloses the inorganic filler comprises 50-95% by weight in the layer. Paragraph 0058 discloses the heat-resistant resin is present at 4-9% by weight. Therefore, R is in the range of 5.6-23.75 which is within the claimed range.),
wherein the heat resistant binder polymer is present in an amount of 7 parts to 11 parts by weight based on a total weight of the porous coating layer (Paragraph 0058 discloses the heat-resistant resin can be present in the layer at 4-9 by weight.).
However, Sano et al. do not teach a fluorine-containing binder or wherein the heat resistant binder polymer has a K-value of 120 or more and a glass transition temperature of 100°C or higher, wherein an amount of fluorine-containing binder polymer is larger than an amount of the heat resistant binder polymer.
Gu et al. teach a porous separating layer and an electrochemical device having the same as a separator. The porous separating layer comprises: a plurality of inorganic particles; a heat-resistant polymer and a binder polymer (Abstract). Further, the inorganic particles include boehmite (An aluminum hydroxide material), the content of the inorganic particles is 30 to 94 parts by weight, the content of the heat-resistant polymer is 1 to 30 parts by weight, and the content of the binder polymer is 5 to 40 parts by weight (Claim 1). Further, the heat-resistant polymer include polyimide (PI; glass transition temperature of about 400°C or higher), polyetheretherketone (PEEK; glass transition temperature of about 143°C, melting point of about 343°C), polyetherimide (PEI; glass transition temperature of about 216°C), polyamideimide (PAI; glass transition temperature of about 274°C), polysulfone (PSF; glass transition temperature of about 190°C), polyarylsulfone (PAS; glass transition temperature of about 230°C), polyethersulfone (PES; glass transition temperature of about 225°C), polyphenylene oxide (PPO; glass transition temperature of about 215°C), and polytetrafluoroethylene (PTFE; melting point of about 327 to 335°C), perfluoroalkoxy alkane (PFA; melting point about 300°C), fluorinated ethylene propylene (FEP; melting point about 250°C), ethylenetetrafluoroethylene (ETFE; melting point about 270°C), polyglycolic acid (PGA; glass transition temperature about 35 to 40°C, melting point about 225 to 230°C), polyethylene terephthalate (PET; glass transition temperature about 70°C, melting point about 265°C), polybutylene terephthalate (PBT; glass transition temperature about 50°C, melting point about 245°C) (Paragraph 0056). Further, the binder can comprise PVDF (Paragraph 0032; Examples).
The mass of the inorganic particles can be 70-75% by weight (Paragraph 0085); the heat-resistant polymer may be 5-10% by weight (Paragraph 0086); the binder may be 20% by weight. Therefore, the amount of the fluorine containing binder is larger than an amount of the heat resistant binder. The R value obtained can range from 7-15.
Therefore, it would have been obvious to one of ordinary skill in the art to modify Sano with Gu in order to improve lifespan, safety, and lower resistance in the battery.
However, neither Sano nor Gu et al. teach wherein the heat resistant binder polymer has a K-value of 120 or more.
Sung et al. teach a porous polymer substrate having a plurality of pores; and a porous coating layer formed on at least one surface of the porous polymer substrate and including a mixture of inorganic particles and a particulate binder polymer, and a polyvinyl pyrrolidone binder polymer (Abstract). Further, the polyvinyl pyrrolidone has a K value of 60-130 (Paragraph 0130) and a molecular weight of 10,000-1,000,000 (Paragraph 0084).
Therefore, it would have been obvious to one of ordinary skill in the art to modify Sano and Gu with Sung in order to control viscosity and adhesiveness.
Regarding claims 4 and 13, the combination of Sano, Gu, and Sung et al. teach the separator for the lithium secondary battery according to claim 1. Further, Gu et al. teach wherein the weight ratio of the heat resistant binder polymer to the fluorine containing binder polymer is 20:80 to 40:60 (The heat-resistant polymer may be 5-10% by weight (Paragraph 0086); the binder may be 20% by weight. Therefore, the weight ratio of heat-resistant binder to fluorine binder maybe 1:4 to 1:2.)
Therefore, it would have been obvious to one of ordinary skill in the art to modify Sano with Gu in order to improve lifespan, safety, and lower resistance in the battery.
Regarding claim 8, the combination of Sano, Gu, and Sung et al. teach the separator for the lithium secondary battery according to claim 1. Further, Sano et al. teach wherein the separator has a thickness of from 2 µm to 10 µm (Paragraph 0019 teaches a total thickness of 30 µm or less.)
Regarding claim 11, the combination of Sano, Gu, and Sung et al. teach a lithium secondary battery, comprising: a cathode, an anode, and a separator interposed between the cathode and the anode, wherein the separator is the same as defined in claim 1 (Sano: paragraph 0004).
Conclusion
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Daniel S. Gatewood, Ph.D.
Primary Examiner
Art Unit 1729
/DANIEL S GATEWOOD, Ph. D/Primary Examiner, Art Unit 1729 January 14th, 2026