DETAILED ACTION
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 4/17/26 has been entered.
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 (plurality of electrically conductive particles) supported by the carbon material, wherein the lithium phosphate comprising primary particles each consisting of a lithium compound including 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 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 that includes 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 4/17/26 have been fully considered but they are not persuasive.
The Applicant argues that “In contrast, conventional granulation techniques produce significantly larger particles (typically ≥ 35 nm) that are not formed on, nor structurally integrated with, conductive supports. Thus, the claimed invention is directed to a specific synthesis-driven architecture, not merely a size-selected material.
This architecture provides demonstrable technical advantages. The conductive supports facilitate electron transport, while the nanoscale particle size reduces internal resistance of the lithium phosphate particles. The resulting composite exhibits markedly improved electrical conductivity relative to conventional systems comprising larger, unsupported particles.
The claimed covering layer further distinguishes the claimed invention. As described in paragraphs [0059]-[0060] of the published application, the carbon-containing layer, derived from a water-soluble carbon source, covers at least a portion of the electrically conductive substance, including both the particles and the supports. This additional structural feature further reduces electrical resistance and enhances electrical conductivity”.
In response, there is no evidence to show that other techniques such as the pulverization method taught by the cited Sukino reference is not capable of forming primary particles having an average particle size ranging from 21 nm to 26 nm. In addition, Sukino 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” (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 ranging 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 lithium phosphate with a carbon derived from a water-soluble carbon source such as sucrose. 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. There are no comparison examples showing an average particle size of greater than 26 nm.
The Applicant further argues that “Miyayama fails to teach or suggest:
(i) the claimed doped lithium phosphate composition;
(ii) the claimed nanoscale particle size in combination with supported particles; and (iii)the claimed covering layer structure.
Furthermore, Miyayama does not provide any teaching or suggestion that would have motivated a person of ordinary skill in the art to modify its disclosure to arrive at the claimed combination of features, nor would such a person have had a reasonable expectation of success in doing so”.
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). The claimed doped lithium phosphate composition is taught by the cited Yamashita reference. Therefore, the selection of a known material based on its suitability for its intended use has generally been held to be prima facie obvious. The claimed nanoscale particle size and the claimed covering layer structure is taught by the cited Sukino reference. Therefore, one of ordinary skill in the art would have been motivated to modify the Miyayama composite to include the claimed nanoscale particle size and covering layer structure in order to shorten the conduction path of electrons in the solid phase, making it possible to maximum the performance of the lithium phosphate compound ([0034]); and to ensure sufficient electron conduction between particles to fully exhibit the effects of the invention, 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 and [0032]).
The Applicant further argues that “First, Yamashita is silent with respect to a hydrothermal synthesis process. In particular, Yamashita does not disclose or suggest a process in which lithium phosphate particles are formed in situ on electrically conductive supports under high-temperature and high-pressure aqueous conditions. As a result, Yamashita does not disclose or suggest electrically conductive particles supported on electrically conductive supports, as required by claim 1. Rather, the particles disclosed in Yamashita are formed independently and are not described as being grown from, or
supported on, a conductive substrate.
Second, Yamashita does not disclose or suggest particles having an average particle size within the narrowly defined range of 21 nm to 26 nm. To the contrary, paragraph [0047] of Yamashita discloses that the primary particle size of the positive electrode active material is preferably from 100 nm to 1 µm. Yamashita further explains that particles having a size of 100 nm or more are advantageous for handling during industrial production, while particles of 1 µm or less facilitate lithium ion diffusion.
Thus, Yamashita not only fails to disclose the claimed nanoscale particle size, but
affirmatively teaches particle sizes that are significantly larger than those recited in claim 1. In doing so, Yamashita directs the skilled person toward a different size regime for reasons of manufacturability and performance. Accordingly, Yamashita teaches away from the use of particles having the claimed size of 21-26 nm.
Third, similar to Miyayama, Yamashita fails to disclose or suggest a covering layer as required by claim 1. As acknowledged in the Office Action, Yamashita does not describe a layer covering at least a portion of the electrically conductive supports. Amended claim 1 further requires that the covering layer covers at least a portion of the electrically conductive substance, including the electrically conductive particles supported on the supports, and comprises carbon derived from a water-soluble carbon source. Yamashita contains no teaching or suggestion of such a coating structure or material”.
In response, the Office first points out that the claims of the present application do not require a hydrothermal synthesis process or any specific process of forming the lithium phosphate particles. 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). The Yamashita reference is relied upon for teaching a positive electrode active material (electrically conductive particles) that is LiMn0.75Fe0.2Mg0.05PO4. The claimed supported particles is taught by the cited Miyayama reference. As stated above, the claimed 21-26 nm particle size is obvious in view of the Sukino reference because there is no evidence of criticality of the claimed range and the claimed covering layer is also taught by the Sukino reference.
The Applicant further argues that “First, Sukino does not disclose or suggest a lithium manganese iron phosphate material doped with magnesium and having the specific composition LiMn0.75Fe0.20Mg0.05PO4 Rather, Sukino is limited to conventional lithium iron phosphate materials and provides no teaching or suggestion toward the claimed modified composition.
Second, Sukino is silent with respect to a hydrothermal synthesis process. In particular, Sukino does not disclose or suggest a process in which lithium phosphate particles are formed in situ on electrically conductive supports under high-temperature and high-pressure aqueous conditions. As a result, Sukino does not disclose or suggest electrically conductive particles supported on electrically conductive supports, as required by claim 1. Rather, the particles disclosed in Sukino are formed independently and are not described as being grown from, or supported on, a conductive substrate.
Third, Sukino does not disclose or suggest particles having an average particle size within the narrowly defined range of 21 nm to 26 nm. Instead, Sukino discloses primary particle sizes for LiFePO4 in the range of 50 nm to 500 nm, which are significantly larger than the claimed range.
Fourth, and critically, Sukino discloses carbon coatings applied to the surfaces of active material particles. In contrast, amended claim 1 requires a covering layer that covers at least a portion of the electrically conductive substance, including not only the electrically conductive particles but also the electrically conductive supports on which the particles are supported. Sukino does not disclose or suggest a coating that extends over a composite structure including both supports and supported particles, nor does it disclose a configuration in which the coating is applied to, or derived in relation to, electrically conductive supports”.
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). First, the claimed doped lithium phosphate composition is taught by the cited Yamashita refence. Second, the claims of the present application do not require a hydrothermal synthesis process and the electrically conductive particles supported on electrically conductive supports is taught by the cited Miyayama reference. Third, particles having an average particle size within the range of 21 nm to 26 nm is obvious in view of Sukino based upon the teaching of reducing the primary particle size of LiFePO4 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]). Fourth, Sukino is relied upon for teaching the concept of coating the surface of the active material particles with a carbon material. So, one of ordinary skill in the art would have recognized that the teachings of Sukino can be applied to the [electrically conductive particles supported by the electrically conductive supports] (active material particles) taught by the Miyayama reference in order to further ensure sufficient electron conduction between particles to improve the performance of the battery.
Conclusion
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/T.S.C/Examiner, Art Unit 1751
/Haroon S. Sheikh/Primary Examiner, Art Unit 1751
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