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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 October 1, 2025 has been entered.
Summary
The Applicant’s arguments and claim amendments received on October 1, 2025 have been entered into the file. Currently, claim 1 is amended; and claims 2 and 7 are cancelled; resulting in claims 1, 3-6, and 8 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.
Claims 1, 3-6, and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Hiroki, et al. (JP 2020095853 A) in view of Tamaki, et al. (US PGPub 2013/0004845 A1, cited on IDS), and further in view of Katsushi, et al. (WO 2016208480 A1), as evidenced by Ballisteri, A., et al. Thermal Decomposition of Acrylonitrile Copolymers Investigated by Direct Pyrolysis in the Mass Spectrometer Die Makromolekulare Chemie: Macromolecular Chemistry and Physics, Vol 180, no. 12 (1979), pp. 2835-2842.
Regarding claims 1 and 6, Hiroki teaches a non-aqueous electrolyte secondary battery with a negative electrode (20) including a negative electrode current collector (21; substrate), a first negative electrode active material layer (22A), and a second negative electrode active material layer (22B), layered in that order (¶ [0007], Ln. 49-53; Fig. 3). The first negative electrode active material layer (22A) contains a first graphite particle group (1) (¶ [0018], Ln. 163-164) and the second negative electrode active material layer (22A) contains a second graphite particle group (2) and a ceramic particle group (3) (¶ [0020], Ln. 190-191). The porosity of the second active material layer is greater than the porosity of the first active material layer (¶ [0007], Ln. 61). The ceramic particle group (3) forms pores (voids) in the second electrode active material layer (22B) (¶ [0021], Ln. 202-203). As shown in the cross-section view in Figure 3, the second active material layer (22B) has more voids than the first active material layer. Hiroki further teaches that the ceramic particles enter the gaps between the graphite particles, forming voids and allowing the second active material layer to have a relatively high porosity (¶ [0008], Ln. 69-72). The pores serve as diffusion paths for lithium ions and the high porosity promotes diffusion of lithium ions, improving input characteristics (¶ [0009], Ln. 76-78).
Hiroki is silent to the number density of voids having a diameter of 3 µm or more per mm2 unit area in a transverse cross section parallel to the thickness direction. Therefore, the reference does not expressly teach that the first negative electrode active material layer has a number density of voids having a diameter of 3 µm or more per unit area of less than 200/mm2 and the second negative electrode active material layer has a number density of voids having a diameter of 3 µm or more per unit area of from 200/mm2 to 1500/mm2.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to adjust the number density of voids having a diameter of 3 µm or more per unit area to less than 200/mm2 in the first negative electrode active material layer and to adjust the number density of voids having a diameter of 3 µm or more per unit area to 200-1500/mm2 in the second negative electrode active material layer through routine optimization. As taught by Hiroki, having a relatively high porosity in the second active material layer promotes the diffusion of lithium ions, improving input characteristics. Additionally, it is well-known in the art that a low porosity of active material results in higher energy density. Based on the teachings of Hiroki, it would be obvious to adjust the amount of ceramic particles used in the second active material layer in order to adjust the number of voids. It would be obvious to one ordinary skill in the art to optimize the porosity of the negative electrode active material layer in order to promote the diffusion of lithium ions while maintaining a high energy density of the battery.
Hiroki is silent to teach the mass density per unit volume of the negative electrode and therefore, does not expressly teach that the mass density per unit volume of the negative electrode active material layer is 1.2 g/cm3 or more.
Tamaki teaches a lithium-ion battery comprising a cathode and an anode, wherein the anode has at least two layers: a collector-side active material layer (24a; first active material layer) provided on the anode collector; and a surface-side active material layer (24b; second active material layer) provided on the collector-side active material layer (¶ [0013], Ln. 1-9). The collector-side active material layer (24a; first active material layer) and the surface-side active material layer (24b; second active material layer) are constructed of an anode active material (21) consisting of carbon material (¶ [0053], Ln. 8-9). The specific surface area of the anode active material in the surface-side active material layer (24b; second active material layer) is greater than the specific surface area of the anode active material in the collector-side active material layer (24a; first active material layer) (¶ [0053], Ln. 11-15) and, as shown in Figure 5, the particle size of the anode active material in the surface-side active material layer (24b; second active material layer) is smaller than the particle size of the anode active material in the collector-side active material layer (24a; first active material layer). Tamaki further teaches that the density of the active material layer is approximately 1.0-1.5 g/cm3 (¶ [0062], Ln. 7-10). Specifically, examples 2-1 – 2-6 and 4-1 – 4-6 teach a density of 1.4 g/cm3 (Table 1, Examples 2-1 – 2-6, 4-1 – 4-6). The density is adjusted during the pressing process (¶ [0063], Ln. 20-23) and Tamaki teaches that a density of the active material layers in this range allows for retention of electrolyte (¶ [0062], Ln. 6-7).
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 of Hiroki to have a mass density per unit volume between 1.0 and 1.5 g/cm3, such as 1.4 g/cm3, as taught by Tamaki, meeting the limitations of claims 1 and 6. The density adjustment could be made during the compression of the negative electrode. One would be motivated to adjust the density within this range in order to allow for adequate retention of the electrolyte within the electrode.
Hiroki further teaches that the second negative electrode active material layer (22A) contains a second graphite particle group (2) and a ceramic particle group (3) (¶ [0020], Ln. 190-191). The ceramic particle group (3) forms pores (voids) in the second electrode active material layer (22B) (¶ [0021], Ln. 202-203). The ceramic particles form pores because they make it difficult for gaps between the particles of the second negative electrode active material layer (22B) to be crushed during compression of the electrode (¶ [0021], Ln. 202-206). Hiroki does not expressly teach that the second electrode active material layer (22B) includes a thermoplastic resin that is degradable in an oxygen-containing atmosphere at a temperature of 200 °C or more.
Katsushi teaches a negative electrode for a nonaqueous secondary battery wherein the negative electrode includes a negative electrode active material, a negative electrode binder, and organic hollow particles having an outer shell made of a thermoplastic resin (¶ [0006], Ln. 60-62). Katsushi teaches that the organic hollow particles introduce voids to the negative electrode active material layer (¶ [0015], Ln. 142-144). Katsushi further teaches that including organic hollow particles in the slurry for the negative electrode results in a secondary battery with excellent cycle characteristics (¶ [0012], Ln 116-119). The particle size of the organic hollow particles is preferably 3.0-10 µm (¶ [0028], Ln. 348-349). The thermoplastic resin is formed by polymerization of a polymerizable monomer component and a crosslinking agent (¶ [0039], Ln. 507-510). The polymerizable monomer is preferably a nitrile-based monomer such as acrylonitrile or methacrylonitrile (¶ [0040], Ln. 516, 521-522) and further includes a monomer other than the nitrile monomer such as a (meth)acrylic acid ester monomer, a carboxyl group-containing monomer, a vinyl ester monomer, or an acrylamide monomer (¶ [0043], Ln. 562-565). Ballisteri teaches that the thermal decomposition of pendant ester groups in methyl acrylate and methyl methacrylate copolymers occurs at 200-260 °C. Additionally, Ballisteri teaches that polyacrylonitrile decomposition fragments are typically detected in the 240-300 °C temperature range (pg. 2835). Based on these teachings, one of ordinary skill in the art would understand that the thermal degradation temperature of the thermoplastic resin of Katsushi is at a temperature above 200 °C. Katsushi also teaches that the organic hollow particles are expanded at a temperature between 90-150 °C, and the maximum expansion temperature is 250 °C (¶ [0034], Ln. 451-456).
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 second negative electrode active material layer (22B) of Hiroki to include organic hollow particles to form voids in the active material layer as taught by Katsushi. Organic hollow particles serve the same purpose as the ceramic particles taught by Hiroki of forming voids in the active material layer. One would be motivated to use organic hollow particles as taught by Katsushi in order to produce a secondary battery with excellent cycle characteristics.
Hiroki further teaches that the first negative electrode active material layer (22A) contains a first graphite particle group (1; first active material particles) (¶ [0018], Ln. 163-164) and the second negative electrode active material layer (22A) contains a second graphite particle group (2; second active material particles) (¶ [0020], Ln. 190-191). Additionally, Hiroki teaches that graphite particles with a relatively small particle size in the surface layer of a negative electrode active material increases reaction area between electrolyte and the graphite particles, improving input characteristics (¶ [0004], Ln. 27-32). Hiroki teaches that the first graphite particle group has a first average particle diameter “d1” and the second graphite particle group has a second average particle diameter “d2” (¶ [0023], Ln. 228-231), further teaching that d1 and d2 satisfy the relationship 0.8≤d2/d1≤1.13 (¶ [0025], Ln. 244-245). Hiroki teaches that the first average particle size is more than 10 µm and less than 30 µm (¶ [0027], Ln. 257), overlapping the claimed range of more than 10 µm and less than 20 µm. Using the relationship between d1 and d2, the resulting second average particle size is more than 8 µm and less than 34 µm, overlapping the claimed range of from 4 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)). Example 5 teaches that average particle diameter of the first graphite particle group (1) is 15 µm and the average particle diameter of the second graphite particle group (2) is 12 µm, using the relationship d2/d1=0.8 and providing an example where the average particle size of the second active material particles is less than an average particle size of the first active material particles (Table 1, Example 5). It would be obvious to one of ordinary skill in the art to select a first average particle size within the taught range, such as 11 µm, and a second average particle size using the relationship d2/d1=0.8, resulting in a particle size of 8.8 µm, based on the teachings of Hiroki.
Regarding claim 3, Hiroki in view of Tamaki and Katsushi teaches all of the limitations of claim 1 above. The relationship between particle size and specific surface area is well-known: the smaller the particle size, the larger the specific surface area. Therefore, as Hiroki teaches a second average particle size that is less than the first average particle size, Hiroki also teaches that the BET specific surface area of the second graphite particle group is more than the BET specific surface area of the first graphite particle group based on the provided average particle size.
Regarding claim 4, Hiroki in view of Tamaki and Katsushi teaches all of the limitations of claim 1 above. Additionally, Hiroki teaches that the mass density per unit volume of the second negative electrode active material layer (22B) is less than the mass density per unit volume of the first negative electrode active material layer (22A), as a higher porosity would result in a lower density. Figure 3 shows the first negative electrode active material layer (22A) and the second negative electrode active material layer (22B), and also demonstrates the high porosity of the second negative electrode active material layer (22B). Figure 3, along with the teaching of Hiroki that the second negative electrode active material layer has a relatively high porosity compared to the first negative electrode active material layer due to ceramic particles entering the gaps between the graphite particles and forming voids in the second negative electrode active material layer (¶ [0008], Ln. 69-72), teaches that the second negative electrode active material layer (22B) has a lower mass density per unit volume than the first negative electrode active material layer (22A).
Regarding claim 5, Hiroki in view of Tamaki and Katsushi teaches all of the limitations of claim 1 above, and Hiroki further teaches that the thickness of the first negative electrode active material layer is 88-111 µm (¶ [0041], Ln. 368-370)) and that the ratio of the thickness (t2) of the second negative electrode active material layer (22B) to the thickness (t1) of the first negative electrode active material layer (22A) is 0.1<(t2/t1)<0.5 (¶ [0039], Ln. 354-355), resulting in a preferred range for the thickness of the second negative electrode active material layer (22B) of 8.8 µm to 55.5 µm, overlapping the claimed range of 10 µm to 40 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)).
Regarding claim 8, Hiroki teaches a non-aqueous secondary battery including a positive electrode, the negative electrode previously referenced, and an electrolyte solution (¶ [0007], Ln. 49-50). Therefore, Hiroki in in view of Tamaki and Katsushi teaches a non-aqueous secondary battery comprising a negative electrode meeting the limitations of claim 1.
Response to Arguments
Response-Claim Rejections – 35 U.S.C. 103
In light of Applicant’s amendment to claim 1 to incorporate the limitations of claim 3 and further limit the average particle size of the first active material particles and second active material particles, the previous rejection of claim 1 under 35 U.S.C. 103 as being unpatentable over Hiroki, et al. (JP 2020095853 A), and further in view of Tamaki, et al. (US PGPub 2013/0004845 A1, cited on IDS) and Katsushi, et al. (WO 2016208480 A1), as evidenced by Ballisteri, A., et al. Thermal Decomposition of Acrylonitrile Copolymers Investigated by Direct Pyrolysis in the Mass Spectrometer Die Makromolekulare Chemie: Macromolecular Chemistry and Physics, Vol 180, no. 12 (1979), pp. 2835-2842 is modified above. Any arguments with respect to the reference that are still deemed valid will be addressed herein.
The Applicant argues, see pages 4-5 of the remarks filed October 1, 2025, that Hiroki does not teach examples with first graphite particles having a particle size within the claimed range of 10 µm to 20 µm and second graphite particles having a particle size within the claimed range of 4 µm to 10 µm and further, that Hiroki discourages the use of graphite with relatively small average particle size. This argument is not persuasive. Although Hiroki does not include specific examples with graphite particles having particle sizes within the claimed ranges, Hiroki teaches that the first graphite particle group has a first average particle diameter “d1” which is more than 10 µm and less than 30 µm (¶ [0027], Ln. 257), overlapping the claimed range of more than 10 µm and less than 20 µm. Further, Hiroki teaches that the second graphite particle group has a second average particle diameter “d2” (¶ [0023], Ln. 228-231), and that d1 and d2 satisfy the relationship 0.8≤d2/d1≤1.13 (¶ [0025], Ln. 244-245). Using the relationship between d1 and d2, the resulting second average particle size is more than 8 µm and less than 34 µm, overlapping the claimed range of from 4 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)). Additionally, Hiroki teaches that graphite particles with a relatively small particle size in the surface layer of a negative electrode active material increases reaction area between electrolyte and the graphite particles, improving input characteristics (¶ [0004], Ln. 27-32).
Conclusion
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/SARAH J JACOBSON/Examiner, Art Unit 1785
/MARK RUTHKOSKY/Supervisory Patent Examiner, Art Unit 1785
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