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 .
Status of Claims
Claims 1-3 and 5-7 are currently pending.
Claim 4 has been cancelled.
Claim 1 has been amended.
Status of Amendment
The amendment filed on October 6th, 2025 has been fully considered but does not place the application in condition for allowance.
Status of Pending Objections and Rejections since the Office Action of July 9th, 2025
The 103 rejections of 1 and 5-7 over Oki are withdrawn in view of the applicant’s amendment.
The 103 rejections of claims 2 and 3 over Oki and further in view of Yoo are withdrawn in view of the applicant’s amendment
The 103 rejection of claim 4 over Oki in view of Kawasaki is moot because the claim has been cancelled.
Response to Arguments
Applicant's arguments filed October 6th, 2025 have been fully considered but they are not persuasive. The applicant argues that Oki does not teach or suggest that the positive electrode active material could be lithium iron phosphate (LiFePO4). Oki, however, discloses that “any conventionally known materials can be used” as the positive active material of their disclosure (Oki, column 5, lines 45-46). As it will be discussed below in the relevant rejection, Kucinskis teaches that “some of the most commonly studied cathode materials for lithium-ion batteries are…LiFePO4” (Graphene in lithium-ion battery cathode materials: A review; Overview). Additionally, this article was published in 2013, further supporting the idea that lithium iron phosphate is one of the conventionally known materials that Oki discusses.
In response to applicant's argument that the claimed configuration of lithium iron phosphate, a thick film, single-walled nanotubes, and dispersed carbon black solves a gas retention problem, the fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985).
Applicant’s arguments with respect to claim 1 regarding Kawasaki have been considered but are moot because the new ground of rejection does not rely on Kawasaki.
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.
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, 5, 6, and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Oki (US 8,003,015 B2) and further in view of Kim (WO 2021/066560 A1, but citations will be drawn to US 2022/0216480 A1) andKucinskis (Graphene in lithium ion battery cathode materials: A review).
Regarding claim 1, Oki teaches a nonaqueous electrolyte secondary battery comprising a positive electrode, negative electrode, and nonaqueous electrolyte where the positive electrode includes a positive electrode current collector and a positive electrode active material formed on the positive electrode current collector (col 16, line 59 – col 17 line 16). Oki teaches that the positive electrode active material layer has an average thickness between 1 µm and 500 µm (col 18, lines 40-41), which overlaps with the claimed range of 100 µm or greater. Oki continues to teach that their positive active material layer is comprised of particles that have an average diameter between 0.1 µm – 10 µm (col 5, lines 65 and 66) ), which overlaps with the claimed range of 10 µm or less. Oki teaches that the positive electrode active material layer also includes “a conductive material (b)” and a “fibrous conductive material (c)” (column 4, lines 34-36). This conductive material (b) may be carbon black (column 6, lines 5-10) and the conductive material (c) may be carbon nanotubes (column 8, lines 23-40). Oki continues to teach that the carbon nanotubes have lengths between 1 µm and 10 µm (col 9, lines 12-23), which overlaps with the claimed range of 1 µm to 2 µm. Oki continues to teach that the carbon nanotubes may have a diameter of 1 nm – 300 nm (col 9, lines 24-29) which overlaps with the claimed range of 10 nm or less. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP 2144.05 (I).
The electroconductive material of Oki is thoroughly dispersed (Examples 1 – 4) and the carbon nanotubes and carbon black are dispersed in a region distinguished from a region where the positive electrode active material is present. Two different objects cannot be in the exact same space; therefore, those different objects are in regions distinguished from each other.
Oki teaches a positive active material in an electrode, but does not specifically mention lithium iron phosphate (LiFePO4). Oki, however, discloses that “any conventionally known materials can be used” as the positive active material of their disclosure (col 5, lines 45-46). Kucinskis is analogous art to Oki because both teach positive active materials for lithium-ion batteries. Kucinskis teaches that “some of the most commonly studied cathode materials for lithium-ion batteries are…LiFePO4” (Graphene in lithium-ion battery cathode materials: A review; Overview). Therefore, it would have been obvious to select LiFePO4 as the positive active material of Oki, because selection of a known material based on its suitability for its intended use supports a prima facie obviousness determination. See MPEP 2144.07.
Oki also fails to specifically teach the usage of single-walled carbon nanotubes. Kim is analogous art to Oki because both teach positive electrodes. Kim teaches that the usage of single-walled carbon nanotubes results in a reduction of the resistance of the positive electrode and “the input/output characteristics and life characteristics of the battery may be significantly improved”(Kim, [0052]). Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the present invention to use the single-walled carbon nanotubes of Kim in Oki’s positive electrode in order to improve the input/output and life characteristics of a battery comprised of Oki’s positive electrode.
Oki modified by Kim and Kucinskis will henceforth be referred to as modified Oki.
Regarding claim 5, modified Oki teaches that the mass ratio between the carbon nanotubes, a “conductive material (c)” may have a mass content between 0.2 to 20 parts by weight relative to 100 parts by weight of the positive electrode active material to enhance the conductivity of the active material layer (Oki, col 9, lines 30 – 44). Modified Oki teaches that carbon black, a “conductive material (b)” may also have a mass content between 0.2 and 20 parts by weight relative to 100 parts by weight of the positive electrode active material to more suitably form composite particles of the active material layer (Oki, col 7, lines 52 – 64). Based on those ranges, both the carbon nanotubes and the carbon black may be 10 parts by weight relative to 100 parts by weight of the positive electrode active material. If they have the same weight relative to positive active material layer, then they would have the same weight. If they have the same weight, the mass ratio of carbon nanotubes to carbon black is 50:50. This is not the only possible combination of weight ratios; modified Oki teaches a range for each material which would result in different ratios that would also be in the range claimed by the applicant. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP 2144.05 (I). Furthermore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the present invention to use the weight percents of the carbon nanotubes and carbon black within the claimed ratio to improve the formation and conductivity of the positive active material layer.
Regarding claim 6, the applicant claims that if a cross-sectional image was taken of the positive active material layer and multiple arbitrary lines were drawn throughout, a ratio of the length d1 (which corresponds to cumulative length of the line segments where the carbon nanotubes and carbon black are present) and the length d2 (which corresponds to cumulative length of the line segments where the positive electrode active material is present) has a value between 0.1 and 0.3.
Let there be a hypothetical cross-sectional image taken of the positive electrode active material layer that contains the full diameter of a carbon black particle and the whole diameter of a particle of the positive active material. A line, arbitrarily drawn such that it includes the full diameter of a carbon black particle and the diameter of the positive active material particle, would have a length d1 that corresponds to the diameter of a particle of carbon black and a length d2 that corresponds with the diameter of the positive active material.
Modified Oki teaches that the particle diameter of the carbon black is preferably one-fifth or less than the primary particle diameter of the positive active material (Oki, col 6, lines 36 - 49). In other words, the ratio of d1 to d2 is equal to one-fifth, which is equal to 0.25, which lies within the range claimed by the applicant.
Regarding claim 7, modified Oki teaches that the content of the conductive materials is preferably 15 parts by weight or less relative to 100 parts by weight of the positive electrode active material (Oki, col 13, lines 48 – 62), which results in a positive electrode active material mass percent much greater than 60%. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP 2144.05 (I). Modified Oki does mention that slurries for positive electrode active material layers do include a binder (Oki, col 14, lines 17-20), but it widely known by person of ordinary skill in the art that binders typically comprise a small amount of active material slurries (<5%).
Claims 2 and 3 are rejected under 35 U.S.C. 103 as being unpatentable over modified Oki as applied to claim 1 above, and further in view of Yoo (US 2020/0343541 A1).
Regarding claim 2, the limitations within are drawn to the amount of variation in areas of electroconductive material in the positive electrode active material layer in a cross-sectional image. Small amounts of variation between the areas indicates that the electroconductive material is well-dispersed. The claim recites that the “variation of the areas…is within 15%.” Modified Oki is silent on the quantitative degree of dispersion. Yoo is analogous art to modified Oki because both teach positive electrodes. Yoo teaches that a “carbon nanotube may be uniformly dispersed to improve life-time characteristics of a battery” [0011]. “Uniformly dispersed” indicates that there is 0% variation, and 0% is less than 15%. Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the present invention to apply the teachings of Yoo to achieve uniform dispersion of the electroconductive material throughout the positive active material layer to improve life-time characteristics of a battery. Furthermore, in the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP 2144.05 (I).
Regarding claim 3, the limitations within are drawn to an amount of electroconductive material present within the positive active material layer of an electrode, quantified by the electroconductive material’s area in a cross-sectional image of the active material layer. This cross-sectional area is closely related to its surface area, and optimizing one value is likely to optimize the other. Therefore, the following rationale that discusses surface area also describes the drawbacks and benefits of having too much or too little area in a cross-sectional image.
Modified Oki teaches a desirable range of surface area of carbon black used as electroconductive material. The range recited is 40 – 100 m3/g. There needs to be enough surface area “from the viewpoint of suitably securing the pore volume of the positive electrode” (Oki, col 12, lines 63 – 65). On the other hand, it is preferably not too great “from the viewpoint of moderately suppressing the capacity of the positive electrode to secure the compactness (Oki, col 12, line 67 – col 13, line 2). Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the present invention to optimize the surface area (or volume) of the electroconductive material in the positive active material layer to 1) secure the pore volume of positive electrode and to 2) moderately suppress the capacity of the positive electrode to secure compactness. "[W]here 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). See MPEP § 2144.05 (II).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Kong (US 2014/0239235 A1) discloses a cathode material comprised of lithium iron phosphate [0047] that may also be comprised of single-walled carbon nanotubes [0016] or conductive carbon black [0015].
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/RYAN K. BLACKWELL-RUDASILL/Examiner, Art Unit 1722
/NIKI BAKHTIARI/Supervisory Patent Examiner, Art Unit 1722