DETAILED ACTION
Response to Amendment
Claims 1 and 4-10 are currently pending. Claims 2 and 3 are cancelled. New claims 7-10 have been added. The amended claims do overcome the previously stated 103 rejections. However, upon further consideration, claims 1 and 4-10 are rejected under the following new 103 rejections. This action is made FINAL as necessitated by the amendment.
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.
Claims 1 and 4-10 are rejected under 35 U.S.C. 103 as being unpatentable over Xia et al (CN 104347842 B, machine translation) in view of Lee et al (KR 10-2019-0019854) using (US 2020/0176753) as an equivalent English translation, and further in view of Sunano et al (US 2017/0346066).
Regarding claims 1, 5-7, and 9, Xia et al discloses a lithium-ion secondary battery (non-aqueous electrolyte secondary battery) comprising a negative electrode sheet (negative electrode), a positive electrode sheet (positive electrode), and an electrolyte (non-aqueous electrolyte); wherein the negative electrode sheet comprises a metal current collector (negative electrode core) and a negative electrode active layer (negative electrode mixture layer) coated (provided) on a surface of the metal current collector, wherein the negative electrode active layer is a bilayer consisting essentially of a first negative electrode active layer (second layer) and a second negative electrode active layer (first layer); wherein the first negative electrode active layer (second layer) is directly disposed on the metal current collector and is disposed between the second negative electrode active layer (first layer) and the metal current collector; wherein the second negative electrode active layer (first layer) includes only natural graphite as the negative electrode active material; wherein the first negative electrode active layer (second layer) includes only a silicon-based active material (element to be alloyed with lithium) as the negative electrode active material ([0023],[0072],[0073]).
However, Xia et al does not expressly teach graphite having a BET specific surface area of 0.5 to 2.5 m2/g; and a second layer that includes a binder (claims 1 and 6).
Lee et al discloses a first negative electrode mixture layer (first layer) including graphite having a specific surface area of 2.5 m2/g as the negative electrode active material; and a second negative electrode mixture composition (second layer) including SiO (element to be alloyed with lithium) and styrene butadiene rubber as a binder ([0099],[0101]).
Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was made to modify the Xia negative electrode active layer to include graphite having a BET specific surface area of 0.5 to 2.5 m2/g, and a second layer that includes a binder in order to utilize a defined specific surface area that improves the adhesion of the negative electrode sheet and to prevent the degradation of bindability among particles caused by severe swelling of particles after lithium ion intercalation during repeated charge/discharge cycles ([0053],[0065]).
However, Xia et al as modified by Lee et al does not expressly teach a mass ratio of binder to the negative electrode active material in the second layer that is 1.5 to 10 times a mass ratio of binder to the negative electrode active material in the first layer.
However, it would have been obvious to one of ordinary skill in the art at the time the invention was made to modify the Xia/Lee negative electrode sheet to include a mass ratio of binder to the negative electrode active material in the second layer that is 1.5 to 10 times a mass ratio of binder to the negative electrode active material in the first layer because it has been held that the discovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art. In re Boesch, 205 USPQ 215 (CCPA 1980). The mass ratio of the binder to the negative electrode active material in the first layer and the mass ratio of the binder to the negative electrode active material in the second layer are result effective variables of optimizing the binding between the negative electrode active material and the conductive material and binding to the current collector. 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. In re Aller, 220 F.2d 454. 456, 105 USPQ 233, 235 (CCPA 1955)). There is no evidence of criticality of the claimed mass ratio of the binder to the negative electrode active material in the first layer and the mass ratio of the binder to the negative electrode active material in the second layer.
However, Xia et al as modified by Lee et al does not expressly teach a second layer including the compound containing the element to be alloyed with lithium as the negative electrode active material, wherein said compound includes at least one of: a SiO particle formed of a silicon oxide phase and elemental Si dispersed in the silicon oxide phase; and an LSX particle formed of a lithium silicate phase and elemental Si dispersed in the lithium silicate phase (claims 1 and 6); wherein the second layer includes the compound containing the element to be alloyed with lithium as the negative electrode active material in a form of particle with a particle size of 4 um to 10 um (claims 7 and 9).
Sunano et al discloses a negative electrode active material particle that includes silicon particles “12” dispersed in a lithium silicate phase “11”, wherein the negative electrode active material particles have an average particle size of 4 to 10 um ([0030],[0062]).
Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was made to modify the Xia/Lee negative electrode active layer to include a second layer including the compound containing the element to be alloyed with lithium as the negative electrode active material, wherein the compound includes an LSX particle formed of a lithium silicate phase and elemental Si dispersed in the lithium silicate phase, wherein the second layer includes the compound containing the element to be alloyed with lithium as the negative electrode active material in a form of particle with a particle size of 4 um to 10 um in order to provide a negative electrode active material with higher capacity and improved cycle characteristics ([0062]). In addition, the invention as a whole would have been obvious to one of ordinary skill in the art at the time the invention was made because the disclosure of Sunano indicates that silicon particles dispersed in a lithium silicate phase is a suitable material for use as negative electrode active material. The selection of a known material based on its suitability for its intended use has generally been held to be prima facie obvious (MPEP §2144.07). As such, it would be obvious to use silicon particles dispersed in a lithium silicate phase.
Regarding claim 4, Xia et al does not expressly teach a negative electrode active material included in the second layer that is present in an amount 0.03 to 9.6 times that of a negative electrode active material included in the first layer.
Lee et al also discloses first negative electrode mixture layer and second negative electrode mixture layer that have the same composition, wherein the first negative electrode mixture layer has a thickness of 40 um and the second negative electrode mixture layer has a thickness of 20 um which corresponds to a negative electrode active material (SiO) included in the second layer that is present in
an amount 0.5 times that of the negative electrode active material (graphite) included in
the first layer based upon the ratio of the thickness of the second layer to the thickness
of the first layer ([0099],[0101]).
Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was made to modify the Xia negative electrode sheet to include a negative electrode active material included in the second layer that is present in an amount 0.5 times that of a negative electrode active material included in the first layer in order to improve the output and life characteristics of the battery ([0139]-[0142] and Table 2).
Regarding claims 8 and 10, Xia et al also discloses a thickness of the silicon-based active material layer (second layer) that is 5 nm to 2 um ([0041]).
However, Xia et al does not expressly teach a second layer that has a thickness of 10 um to 120 um (claims 8 and 10).
However, it would have been obvious to one of ordinary skill in the art at the time the invention was made to modify the Xia negative electrode sheet to include a second layer that has a thickness of 10 um to 120 um because changes in size was held to have been obvious (In re Rose, 220 F.2d 459, 105 USPQ 237 (CCPA 1955)). An increase in the thickness of the silicon-based active material layer would necessarily result in a higher capacity battery due to the increase in the amount of silicon-based active material. There is no evidence of criticality of the claimed thickness of the second layer.
Response to Arguments
Applicant’s arguments with respect to claims 1 and 4-10 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
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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/T.S.C/Examiner, Art Unit 1751
/JONATHAN G LEONG/Supervisory Patent Examiner, Art Unit 1751 11/3/2025
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