DETAILED ACTION
The applicant’s amendment filed on September 30, 2025 was received. Claims 1 and 2 were amended.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office 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 .
Claim Rejections - 35 USC § 102
In view of Applicant’s amendment of claim 1, the Examiner withdraws the previously set forth rejection of claims 1 and 4 under 35 U.S.C. 102(a)(1) as being anticipated by Kondo as detailed in the Office action dated July 2, 2025.
Claim Rejections - 35 USC § 103
In view of Applicant’s amendment of claim 1, the Examiner withdraws the previously set forth rejection of claims 2 and 3 under 35 U.S.C. 103 as being unpatentable over Kondo as detailed in the Office action dated July 2, 2025.
Claims 1-4 are rejected under 35 U.S.C. 103 as being unpatentable over Kondo et al. (hereinafter “Kondo”) (U.S. Pub. No. 2016/0308185A1, already of record) in view of Lu et al. (hereinafter “Lu”) (CN 111129402 A; see English machine translation).
Regarding claims 1 and 4, Kondo teaches a lithium-ion secondary battery 100 comprising a long sheet-shaped separator 70 which includes a substrate layer 90 formed of a porous separator substrate, and a heat resistance layer 80 formed on one surface of the substrate layer 90 (see paragraphs 32 and 69). The heat resistance layer 80 contains heat-resistant fine particles and a binder (see paragraph 36). The separator is formed such that the amount of the binder contained per unit volume in a heat resistance layer end portion 82 positioned at an end portion 70a in the width direction DW perpendicular to the longitudinal direction DL of the separator 70 is higher than the amount of the binder contained per unit volume in a heat resistance layer center portion 84 positioned at a center portion 70b that includes at least the center in the width direction DW of the separator 70 (see paragraph 48; FIG. 2).
Kondo is silent as to a higher binder content in a part facing an edge portion of the electrode in a longitudinal direction.
Lu teaches a composite membrane for a battery separator characterized in that the membrane has two edges along a length of the membrane and two edges along the width of the membrane (see paragraphs 68 and 89). The edges are characterized by an average content of a binder adhesive that is at least 10% by weight higher than an average content of the binder adhesive in the remaining composition forming the composite membrane (see paragraph 69). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the separator of Kondo to increase the binder content along the width direction and the longitudinal direction as taught by Lu because Lu teaches that this reduces a tendency of cracks to form in the edge area during processing of the separator (see paragraph 87).
Regarding claim 2, Kondo teaches that the mass ratio between the filler and the binder contained in the heat resistance layer 80 may be 90:10 to 99.8:0.2 (see paragraph 47).
Although Kondo does not provide separate mass ratios for binder contained in the heat resistance layer end portion 82 and the heat resistance layer center portion 84, Kondo does teach that by increasing the amount of the binder in the heat resistance layer, the peel strength between the substrate layer and the heat resistance layer can be increased. Particularly, increasing the amount of the binder in a region of the heat resistance layer which is close to the substrate layer is effective in increasing the peel strength. Accordingly, thermal shrinkage of the separator can be suppressed. Furthermore, a portion of the heat resistance layer with a high amount of the binder per unit volume tends to cause charge carriers (typically lithium ions) to be less likely to diffuse therethrough. Since the center portion in the width direction of the separator is typically positioned to be interposed between the positive electrode active material layer and the negative electrode active material layer, when the penetration of the charge carriers at the center portion of the heat resistance layer is degraded, there is concern of an increase in the battery resistance of the battery constructed by using the separator. Therefore, by reducing the amount of the binder contained in the heat resistance layer positioned at the center portion in the width direction of the separator to be lower than the amount of the binder contained in the heat resistance layer positioned at the end portion in the width direction of the separator, the penetration of the charge carriers at the center portion in the width direction of the separator can be further ensured in contrast to a case of increasing the peel strength of the entire heat resistance layer on the substrate layer by increasing the amount of the binder in the entire heat resistance layer. Accordingly, the battery resistance of the battery constructed by using the separator can be reduced.
Thus, in consideration of the thermal shrinkage and resistance of the separator of Kondo, it is clear that the amount of binder contained in the heat resistance layer end portion 82 and in the heat resistance layer center portion 84 is a result-effective variable. It has been held by the courts that discovering an optimum value or workable ranges of a known result-effective variable involves only routine skill in the art, and is thus not novel. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980) (see MPEP § 2144.05).
Additionally, differences in concentration or temperature will generally not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. Where 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) (see MPEP § 2144.05).
Regarding claim 3, Kondo teaches that by laminating the separators 70 and the positive and negative electrodes 50, 60 so as to allow the heat resistance layer 80 to face the negative electrode active material layer 64, in a case where the negative electrode active material layer 64 generates heat due to overcharging or the like, the substrate layer 90 of the separator can be protected on the generated heat. On the other hand, by laminating the separators 70 and the positive and negative electrodes 50, 60 so as to allow the heat resistance layer 80 to face the positive electrode active material layer 54, direct contact between the positive electrode 50 and the substrate layer 90 of the separator 70 is prevented, and thus the oxidation of the separator substrate 90 due to the positive electrode 50 can be prevented (see paragraph 71).
Thus, although Kondo only teaches the heat resistance layer 80 on a single surface of the separator substrate 90, it would have been obvious to one of ordinary skill in the art to have provided the heat resistance layer 80 on both surfaces of the separator substrate 90 in order to protect the substrate layer 90 from heat generated in the case of overcharging and the like, while also protecting the separator substrate 90 from oxidation due to the positive electrode 50. It has been held by the courts that mere duplication of parts has no patentable significance unless a new and unexpected result is produced. See In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 1960) (see MPEP § 2144.04).
Response to Arguments
Applicant’s arguments with respect to claim(s) 1-4 have been considered but are no longer relevant to the current rejection(s).
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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/STEPHAN J ESSEX/Primary Examiner, Art Unit 1727