DETAILED 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 .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 April 28, 2026 has been entered.
Summary
The Applicant’s arguments and claim amendments received April 28, 2026 have been entered into the file. Currently, claims 1 and 11 are amended; and claims 2, 4-5, and 9-10 are cancelled; resulting in claims 1, 3, 6-8, and 11 pending for examination.
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, 3, 6-7, and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Matsuno, et al. (US PGPub 2019/0058189 A1, cited on IDS), and further in view of Oh (US PGPub 2021/0184204 A1).
Regarding claim 1, Matsuno teaches a lithium ion secondary battery including a negative electrode comprising a negative electrode active material (¶ [0036], Ln. 1-4). Matsuno teaches that the negative electrode includes a negative electrode active material layer arranged on a negative electrode current collector (¶ [0054], Ln. 1-3). The negative electrode active material layer includes a negative electrode active material, a negative electrode binder, and a conductive additive (¶ [0058], Ln. 1-6). The negative electrode active material is a silicon oxide material which includes silicon compound particles (silicon-based active material) (¶ [0061], Ln. 1-3).
Matsuno also teaches that the aspect ratio is the ratio of Dl/Ds, which is the ratio of Dl, a long diameter of a particle, to Ds, a short diameter of a particle, and is an average of 1 or more and 1.4 or less (¶ [0083], Ln. 1-8). Because the aspect ratio of the claimed invention is the ratio of a short diameter of a particle to a long diameter of a particle, the inverse of the aspect ratio of Matsuno is used to calculate elongation. Given the range of aspect ratios of 1-1.4, the comparable range of elongation is 0-0.29 as shown below.
In Examples 1-2 to 4-1, the Dl/Ds values range from 1.1-1.5, resulting in comparable elongation values of 0.09-0.33, overlapping the claimed range of 0.20-0.25, and specifically Example 4-3 teaches an Dl/Ds value of 1.3, resulting in a comparable elongation value of 0.23, within the claimed range of 0.20-0.25. (Table 4, Examples 1-2 to 4-4).
Matsuno teaches that the circularity, defined as a ratio of Lc, which is a circumferential length of a circle having the same projected area as a particle, to Lp, which is a circumferential length of the particle, is an average of 0.93 or more (¶ [0080], Ln. 1-9). Matsuno teaches that when the circularity of the negative electrode active material particles is sufficiently high, the initial efficiency of the negative electrode active material can be enhanced more effectively (¶ [0081], Ln. 1-12). In Examples 1-2 to 4-1, the circularity ranges from 0.88 to 0.97, overlapping the claimed range of 0.92-0.98, and specifically Examples 1-2, 4-1, and 4-4 teach circularities of 0.97, 0.93, and 0.95, respectively, within the claimed range of 0.92-0.98. (Table 4, Examples 1-2 to 4-4). Matsuno does not expressly teach an embodiment including both an elongation within the claimed range of 0.20-0.25 and a circularity within the claimed range of 0.92-0.98.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the negative electrode active material particles to have an elongation of 0.20-0.25 and circularity of 0.92-0.98 based on the teachings of Matsuno, as Matsuno teaches overlapping ranges of elongation and a preferred circularity of 0.93 or more. More specifically, based on the teachings of Matsuno and examples provided, it would be obvious to modify the negative electrode active material particles to have a circularity such as 0.93, 0.95, or 0.97. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists (MPEP 2144.05 (I)).
Additionally, Matsuno teaches that the negative electrode active material particles include carbon material in the surface portion in order to enhance conductivity (¶ [0075], Ln. 1-6). The median diameter of the negative electrode active material particles is 1.0 µm or more and 15 µm or less (¶ [0024], Ln. 1-3), overlapping the claimed range of 0.1 µm to 10 µm. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists (MPEP 2144.05(I)).
Matsuno further teaches that the silicon compound particles include at least any one kind or more kinds of Li2SiO3 and Li4SiO4 (metal silicate) (¶ [0062], Ln. 1-3). Matsuno does not expressly teach that that the metal silicate includes magnesium silicate, the magnesium silicate including Mg2SiO4 or MgSiO3.
Oh teaches a negative electrode active material for a secondary battery comprising a silicon oxide composite which includes silicon oxide (¶ [0010], Ln. 1-4), and that the silicon oxide composite includes a carbon-containing coating layer on the surface (¶ [0036], Ln. 1-6). Oh additionally teaches adding magnesium silicate to the negative electrode active material in order to improve battery performance by inhibiting expansion and contraction of silicon (¶ [0027], Ln. 5-8). Oh teaches that the magnesium silicate may include at least one of MgSiO3 and Mg2SiO4 (¶ [0028], Ln. 1-5).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the negative electrode active material of Matsuno by adding a magnesium silicate represented by MgSiO3 or Mg2SiO4 as taught by Oh. One of ordinary skill in the art would have been motivated to do this in order to improve battery performance by inhibiting expansion and contraction of silicon.
Regarding claim 3, Matsuno in view of Oh teaches all of the limitations of claim 1 above. Matsuno further teaches that the silicon compound particles included in the negative electrode active material include SiOx (0.5≤x≤1.6) (¶ [0061], Ln. 1-5).
Regarding claim 6, Matsuno in view of Oh teaches all of the limitations of claim 1 above. Matsuno does not expressly teach that the metal of the metal silicate is included at from 0.1-30 wt% in the silicon compound particles.
Oh teaches adding magnesium silicate to the negative electrode active material in order to improve battery performance by inhibiting expansion and contraction of silicon (¶ [0027], Ln. 5-8). Oh teaches that the magnesium is included in an amount preferably between 4-20 wt% with respect to the total weight of the silicon composite oxide (¶ [0029], Ln. 1-7), and that initial charging or discharging efficiency may be decreased when magnesium is included in an amount of less than 2 wt% and capacity retention rate and handling stability may be decreased when magnesium is included in an amount of more than 40 wt% (¶ [0030], Ln. 1-8).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to include the magnesium in an amount between 4-20 wt% with respect to the total weight of the silicon composite oxide, as taught by Oh. One would be motivated to include the magnesium in this weight percent in order to improve initial charging or discharging efficiency and improve capacity retention rate and handling stability.
Regarding claim 7, Matsuno in view of Oh teaches all of the limitations of claim 1 above. Matsuno further teaches that the negative electrode active material particles including silicon and carbon-based active material are blended with the mass ratio 1:9 to obtain the negative electrode active material (¶ [0142], Ln. 1-4). Matsuno teaches that the negative electrode active material is combined with conductive additive 1, conductive additive 2, a styrene-butadiene rubber binder, and a carboxymethyl cellulose binder with the mass ratio 92.5:1:1:2.5:3 to form the negative electrode layer (¶ [0143], Ln. 1-8), resulting in a silicon compound content in the negative electrode layer of 9.25% by mass.
Regarding claim 11, Matsuno in view of Oh teaches a negative electrode meeting the limitations of claim 1 above. Matsuno does not expressly teach that the carbon material on the surface of the negative electrode active material particles is included in an amount of from 0.1-50 wt% based on a total weight of the silicon-based active material.
Oh additionally teaches that the silicon oxide composite negative electrode active material comprises a carbon-containing coating layer on the surface thereof (¶ [0036], Ln. 1-6). Oh teaches that the carbon-containing coating layer is included in an amount of 2-20 wt% with respect to the total weight of the silicon oxide composite (¶ [0036], Ln. 6-8). Oh teaches that when the carbon-containing coating layer is included in an amount less than 2 wt%, an effect of improving sufficient conductivity cannot be expected, and lifetime for an electrode of a lithium secondary battery may be deteriorated, and when the carbon-containing coating layer is included in an amount more than 20 wt%, discharge capacity may be decreased, and charging or discharging capacity per unit volume may be lowered (¶ [0036], Ln. 14-22).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the carbon material on the surface of the negative electrode active material particles of Matsuno to be included in an amount of from 2-20 wt%, within the claimed range of 0.1-50 wt%, based on the teachings of Oh. One of ordinary skill in the art would be motivated to keep the amount of carbon coating within this range in order to sufficiently enhance conductivity without lowering the charging or discharging capacity.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Matsuno, et al. (US PGPub 2019/0058189 A1) in view of Oh, et al. (US PGPub 2021/0184204 A1) as applied to claim 1 above, and further in view of Kizaki, et al. (US PGPub 2018/0309160 A1).
Regarding claim 8, Matsuno in view of Oh teaches all of the limitations of claim 1 above. Matsuno additionally teaches that a small surface area of the silicon compound particles reduces side reactions, enhancing retention rate (¶ [0175], Ln. 1-5). Matsuno in view of Oh does not expressly teach that the BET specific surface area of the silicon-based active material is from 1-60 m2/g.
Kizaki teaches a negative electrode powder which is used in the negative electrode of a secondary battery (¶ [0022], Ln. 1-4). The negative electrode powder includes silicon oxide and a lithium compound, which generates lithium silicate (¶ [0029], Ln. 1-4). Kizaki teaches that a carbon film is formed on the surface of the particles constituting the powder (¶ [0043], Ln. 1-3). Additionally, the BET specific surface area of the powder is within a range of 0.5-15 m2/g (¶ [0037], Ln. 3). Kizaki teaches that this specific surface area allows for favorable dispersibility and application properties of the slurry (¶ [0037], Ln. 3-5).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the specific surface area of the silicon compound particles taught by Matsuno to be within the range taught by Kizaki. One of ordinary skill in the art would be motivated to do this in order to allow for favorable dispersibility and application properties of the slurry.
Response to Arguments
Response-Claim Rejections – 35 U.S.C. 112
The previous rejection of claim 1 under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement is overcome by Applicant’s amendment to the claim.
Response-Claim Rejections – 35 U.S.C. 103
In light of the amendment to claim 1, the previous rejections of claims 1-3, 6-7, 9, and 11 under 35 U.S.C. 103 over Matsuno, et al. (US PGPub 2019/0058189 A1) in view of Oh (US PGPub 2021/0184204 A1) have been modified above. Applicant's arguments filed April 28, 2026 have been fully considered but are not considered persuasive. The Applicant argues that the unexpected results are commensurate in scope with the claims and that neither Matsuno nor Oh teaches the combination of all limitations recited in amended claim 1.
With respect to the argument, see page 6 of the remarks, that the unexpected results are commensurate in scope with the claims, this argument is not persuasive. It is noted that the data relied upon, as explained in the remarks filed December 26, 2025, pertains to battery cells including a negative electrode prepared according to Examples 3 and 4 of the instant specification. The preparation of Examples 3 and 4 includes combining the silicon-based active material with natural graphite in a weight ratio of 1:9, mixing with carbon black, carboxymethylcellulose and SBR, and coating the slurry onto a copper current collector. It is noted that claim 1 recites that the negative electrode includes a current collector and a negative electrode active material layer with the negative electrode active material, conductive material, and a binder, however the examples relied upon specifically include a copper current collector and mix the silicon-based active material with natural graphite in a weight ratio of 1:9 in order to form the negative electrode active material, which is then further combined with conductive material and binder to form the negative electrode active material layer. Thus, the Applicant’s arguments are not commensurate in scope with the claimed invention. Whether the unexpected results are the result of unexpectedly improved results or a property not taught by the prior art, the "objective evidence of nonobviousness must be commensurate in scope with the claims which the evidence is offered to support” (MPEP 716.02 (d)).
With respect to the argument, see page 6 of the remarks, that neither Matsuno nor Oh teaches the combination of all limitations recited in amended claim 1, this argument is not persuasive. While it is acknowledged that Matsuno does not expressly teach an embodiment including both an elongation within the claimed range of 0.20-0.25 and a circularity within the claimed range of 0.92-0.98, the reference teaches overlapping ranges of elongation and a preferred circularity of 0.93 or more. Further, Matsuno teaches the advantages of circularity and elongation, teaching that when circularity of the negative electrode active material is high, the specific surface area is low, and initial efficiency of the negative electrode active material is enhanced (¶ [0015], Ln. 1-7), and that when the ratio of the long diameter of the particle to the short diameter of the particle is within 1-1.4 (which corresponds to an aspect ratio of 0-0.29 using the calculation provided in the instant specification), the contact area among particles increases, and the cycle characteristics are enhanced (¶ [0016]-[0017]). Thus, it would have been obvious to one of ordinary skill in the art to modify the negative electrode active material particles to have an elongation of 0.20-0.25 and circularity of 0.92-0.98 based on the teachings of Matsuno. Additionally, while it is acknowledged that Matsuno does not expressly teach that the metal silicate included in the silicon compound particles includes a magnesium silicate represented by Mg2SiO4 or MgSiO3, it would have been obvious to modify the negative electrode active material of Matsuno by adding MgSiO3 or Mg2SiO4 based on the teachings of Oh. One of ordinary skill in the art would have been motivated to do this in order to improve battery performance by inhibiting expansion and contraction of silicon. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Conclusion
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/SARAH J JACOBSON/Examiner, Art Unit 1785
/MARK RUTHKOSKY/Supervisory Patent Examiner, Art Unit 1785
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