DETAILED ACTION
Response to Amendment
Claims 1, 2, 5, 11-14, 22, 24, and 25 are current pending. Claims 3, 4, 6-10, 15-21, and 23 are cancelled. The amended claims do not overcome the previously stated 103 rejections. Therefore, upon further consideration, claims 1, 2, 5, 11-14, 22, 24, and 25 are rejected under the following 103 rejection.
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, 2, 5, 11-14, 22, 24, and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Miyayama et al (JP 2005123107 A, machine translation) in view of Yamashita et al (US 2018/0083284), and further in view of Sukino et al (JP 2011228293 A, machine translation).
Regarding claims 1, 2, 5, 11-14, 22, 24, and 25, Miyayama et al discloses an electrochemical device (lithium ion secondary battery) comprising:
a positive electrode;
a negative electrode; and
a nonaqueous electrolyte (electrolytic solution);
wherein the positive electrode comprises:
a positive electrode current collector and a positive electrode mixture (positive electrode active material layer) that is provided on the positive electrode current collector and includes a composite (electrically conductive substance) comprising:
a carbon material (plurality of electrically conductive supports), each carbon material comprising artificial graphite (sheet-shaped carbon material), acetylene black, carbon black (spherical carbon material), carbon fiber (fibrous carbon material), or carbon nanotube;
a lithium phosphate compound (plurality of electrically conductive particles) supported by the carbon material, wherein the lithium phosphate compound comprising primary particles that are formed on and coupled to surfaces of the carbon material (electrically conductive supports) and consisting of a lithium compound comprising a lithium phosphate compound represented by LiFePO4 ([0013],[0016]-[0020],[0026] and Fig. 2).
However, Miyayama et al does not expressly teach a lithium phosphate compound represented by LiMn0.75Fe0.20Mg0.05PO4 (claim 1).
Yamashita et al discloses a positive electrode active material (electrically conductive particles) that is LiMn0.75Fe0.20Mg0.05PO4 ([0145]).
Therefore, 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 Yamashita indicates that LiMn0.75Fe0.20Mg0.05PO4 is a suitable material for use as a positive 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 LiMn0.75Fe0.20Mg0.05PO4.
However, Miyayama et al as modified by Yamashita et al does not expressly teach primary particles having an average particle size ranging from 21 nm to 26 nm; and a covering layer covering at least a part of the electrically conductive supports and the electrically conductive particles supported thereon to thereby cover at least a part of the electrically conductive substance, the covering layer comprising carbon derived from a water-soluble carbon source (claim 1); the secondary particles having an average particle size from 50 nanometers to 1000 nanometers (claim 2); wherein the positive electrode active material layer further includes a positive electrode active material (claim 12); wherein the average particle size of the electrically conductive particles is 26 nm (claim 22); wherein the carbon source of the covering layer includes sucrose (claim 25).
Sukino et al teaches the concept of coating a surface of active material particles such as lithium phosphate (electrically conductive substance) with carbon (covering layer) that can be obtained by heat treating a carbon source that is water soluble such as sucrose; wherein the average particle size of the secondary particles is preferably 0.5 (500 nm) to 50 um (50,000 nm) and the particle size of the primary particles of LiFePO4 is 50 nm to 500 nm; wherein the positive electrode active material layer further includes a lithium transition metal composite oxide (positive electrode active material) ([0032]-[0034]).
Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was made to modify the Miyayama/Yamashita composite to include primary particles of a lithium phosphate compound having an average particle size of 50 nm to 500 nm and secondary particles having an average particle size from 500 nm to 50,000 nm; a covering layer covering at least a part of the carbon material and the lithium phosphate compound supported thereon to thereby cover at least a part of the composite (electrically conductive substance), the covering layer comprising carbon derived from a water-soluble carbon source such as sucrose; wherein the positive electrode active material layer further includes a positive electrode active material such as lithium transition metal composite oxide in order to ensure sufficient electron conduction between particles to fully exhibit the effects of the invention ([0032]); thereby providing a battery having a high ratio of a low-SOC output with respect to a high-SOC output, and a high energy density (Abstract). In addition, it would have been obvious to one of ordinary skill in the art at the time the invention was made to modify the Miyayama/Yamashita/Sukino composite to include primary particles of the lithium phosphate compound having an average particle size ranging from 21 nm to 26 nm or 26 nanometers and secondary particles having an average particle size from 50 nanometers to 1000 nanometers 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). Sukino et al also discloses that by reducing the primary particle size of LiFePO4, the conduction path length of electrons in the solid phase and the diffusion path length of Li ions can be shortened, making it possible to maximize the performance of the LiFePO4 ([0034]). So, the average particle sizes of the primary particles and secondary particles are result effective variables of shortening the conduction path length of electrons in the solid phase and the diffusion path length of Li ions to maximize the performance of the lithium phosphate compound. 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 average particle size of primary particles and secondary particles the lithium phosphate compound. Lastly, the Office takes the position that the Sukino carbon covering layer inherently covers at least a part of the Miyayama composite (electrically conductive substance).
Response to Arguments
Applicant's arguments filed 9/14/26 have been fully considered but they are not persuasive.
The Applicant argues that “Miyayama does not teach or suggest LiMn0.75Fe0.20Mg0.05PO4 primary particles that are formed on and coupled to surfaces of electrically conductive supports, as required by claim 1. Nor does Miyayama teach or suggest primary particles having an average particle size of 21 nm to 26 nm. Further, Miyayama does not teach or suggest a carbon-containing covering layer covering at least a part of both the electrically conductive supports and the electrically conductive particles supported thereon. Accordingly, Miyayama does not disclose or suggest the claimed support-coupled architecture, either alone or in combination with the additional features recited in claim 1.
Yamashita is directed to a different electrode technology involving lithium fluoride distribution in an electrode layer, and does not teach or suggest LiMn0.75Fe0.20Mg0.05PO4 primary particles formed on and coupled to surfaces of electrically conductive supports, as required by claim 1. Yamashita teaches a preferred primary particle size of 100 nm to 1 µm for the positive electrode active material, explaining that particles of 100 nm or more are advantageous for industrial handling and particles of 1 µm or less facilitate lithium-ion diffusion (see paragraph [0047] of Yamashita). Thus, far from suggesting the claimed primary particle size of 21 nm to 26 nm, Yamashita expressly identifies substantially larger particles as preferred. A person of ordinary skill in the art following Yamashita's teachings would therefore have been guided toward particle sizes well outside the presently claimed range, rather than toward the claimed nanoscale particles. Furthermore, as acknowledged by the Examiner, Yamashita does not teach or suggest a carbon-containing covering layer covering at least a part of both the electrically conductive supports and the electrically conductive particles supported thereon. Accordingly, Yamashita supplies only the recited chemical composition and does not remedy the deficiencies of Miyayama with respect to the claimed support-coupled particle architecture, the claimed particle-size range, or the claimed covering-layer arrangement. structure recited in claim 1.
Sukino does not teach or suggest the formation of LiMno.75Fe0.20Mg0.05PO4 primary particles on and coupled to surfaces of electrically conductive supports, as required by claim 1. Rather, Sukino treats the active material particles as pre-existing particles that may subsequently be coated with carbon. Importantly, coating active material particles with carbon is not equivalent to forming the active material particles on electrically conductive supports and coupling the particles to those supports. Sukino does not teach or suggest a structure in which the lithium phosphate primary particles are formed on and coupled to surfaces of the conductive supports themselves, nor does Sukino teach or suggest a composite substance in which such supported and coupled particles are thereafter covered, at least in part, by a carbon-containing covering layer”.
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). Miyayama is relied upon for teaching a plurality of electrically conductive particles supported by carbon material (electrically conductive supports), wherein the electrically conductive particles are formed on and coupled to surfaces of the carbon material, wherein the electrically conductive particles consists of a lithium compound comprising a lithium phosphate compound. Although Miyayama does not expressly teach “primary particles having an average particle size of 21 nm to 26 nm”, Sukino is relied upon for teaching the concept of reducing the primary particle size of LiFePO4 in order to shorten the conduction path length of electrons in the solid phase and the diffusion path length of Li ions, making it possible to maximize the performance of the LiFePO4” (see para. [0034]). Based upon this teaching, one of ordinary skill in the art would have been motivated to reduce the particle size of a lithium phosphate compound to include primary particles having an average particle size of less than 50 nm such as from 21 nm to 26 nm in order to shorten the conduction path length of electrons, thereby reducing the internal resistance of the lithium phosphate particles. In addition, Sukino further teaches the concept of coating a surface of active material particles (such as a composite of lithium phosphate compound supported by a carbon material taught by Miyayama) with a carbon derived from a water-soluble carbon source such as sucrose. One of ordinary skill in the art would have recognized that this teaching of Sukino could be applied to Miyayama composite in order to ensure sufficient electron conduction between particles to fully exhibit the effects of the invention (Sukino, [0032]). The Sukino teaching of a carbon source such as a liquid organic substance necessarily covers at least a part of the Miyayama composite (electrically conductive supports and electrically conductive particles supported thereon) to thereby cover at least a part of the composite (electrically conductive substance).
In addition, the Yamashita reference is relied upon for teaching a positive electrode active material (electrically conductive particles) that is LiMn0.75Fe0.2Mg0.05PO4. Therefore, the selection of a known material based on its suitability for its intended use has generally been held to be prima facie obvious.
Lastly, the Office points out that the Applicant has not provided sufficient evidence to show the criticality of the claimed average particle size ranging from 21 nm to 26 nm. Table 1 of the present application only shows Examples 2 and 4 having an average particle size of 26 nm and 21 nm, respectively. Although Table 1 shows Example 5 of a lithium phosphate compound LMFMP having an average particle size of 43 nm, this lithium phosphate compound is not supported on an electrically conductive support or covered with a covering layer. Therefore, one of ordinary skill in the art would not be able to ascertain whether the decrease in discharge capacity and charge capacity retention rate is due to the larger average particle size of the lithium phosphate compound. Absent evidence of criticality of the claimed average particle size of the lithium phosphate compound, the Office maintains the contention that it would have been obvious to one of ordinary skill in the art to optimize the average particle size in order to shorten the conduction path length of electrons in the solid phase and the diffusion path length of Li ions. By shortening the conduction path length of electrons in the solid phase, the impedance of the Miyayama composite would necessarily be decreased.
The Applicant further argues that “The present application further supports the significance of the claimed structural relationship. The specification explains that, during hydrothermal synthesis, crystals of the lithium phosphate compound grow on surfaces of the electrically conductive supports and that the resulting electrically conductive particles are firmly coupled to the supports, for example through interaction with functional groups present on the support surfaces (see paragraphs [0038]-[0039] of the application as filed). This support-coupling relationship secures electrical conductivity through the electrically conductive supports, while the extremely small primary particle size reduces electrical resistance of the lithium phosphate particles (see paragraph [0041] of the application as filed). The application further explains that the carbon-containing covering layer decreases electrical resistance and improves electrical conductivity”.
In response, the Office first points out that Miyayama discloses that “The obtained mixture was placed in a pressure vessel and subjected to hydrothermal synthesis … to obtain a composite of LiFePO4 and a carbon material” (see para. [0028]). Since Miyayama teaches the same hydrothermal synthesis as the present invention, Miyayama necessarily teaches the same structural relationship between the lithium phosphate compound and the electrically conductive supports. In addition, Sukino also teaches extremely small primary particle size that reduces electrical resistance of the lithium phosphate particles. Lastly, Sukino teaches the same covering layer as the present invention that improves the electron conductivity and as a result decreases electrical resistance (see para. [0032]).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Tsuji et al (US 2017/0352879) discloses a lithium manganese phosphate (lithium phosphate compound) having a crystallite size (primary particle average particle size) that is greater than or equal to 10 nm and less than or equal to 50 nm … When the crystallite size exceeds 50 nm, an excessive voltage is required for desorption of lithium ions from lithium manganese phosphate at the time of charging. Moreover, having a crystallite size of less than 10 nm results in a state of having substantially no crystallinity, making it difficult for lithium to be extracted and inserted reversibility ([0021]). Tsuiji et al further teaches a covering layer covering the lithium manganese phosphate nanoparticles, the covering layer comprising a carbon derived from glucose (water-soluble carbon source).
THIS ACTION IS MADE FINAL. 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to TONY S CHUO whose telephone number is (571)272-0717. The examiner can normally be reached Monday - Friday, 9:00am - 5:30pm.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jonathan Leong can be reached on 571-270-1292. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/T.S.C/Examiner, Art Unit 1751
/JONATHAN G LEONG/Supervisory Patent Examiner, Art Unit 1751 10/8/2026
