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, 2, and 5-11 are pending.
Claim 6 has been amended.
Status of Amendment
The amendment filed on May 1st, 2025 has been fully considered but does not fully place the application in condition for allowance.
Status of Objections and Rejections Pending since the Office Action of February 2nd, 2026
The 112(b) rejection of claim 6 has been withdrawn in view of the Applicant's amendment.
The 103 rejections of claims 1, 2, and 5-10 are maintained.
The 103 rejection of claim 11 is withdrawn in view of the Applicant’s arguments.
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.
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, 2, and 5-10 are rejected under 35 U.S.C. 103 as being unpatentable over Du (US 2020/0006767 A1) and further in view of Suhara (US 7,381,498 B2) and Kuroda (US 2021/0083286 A1).
Regarding claim 1, Du teaches a positive electrode comprised of a current collector and a positive electrode mixture layer containing positive electrode active material disposed on the surface of the current collector (abstract). The positive electrode active material layer includes a first and a second sublayer, which correspond to the claimed “regions” (abstract). Both the first and second sublayer are wholly comprised of the first and second positive active materials since the electrode is formed by sequentially applying the corresponding electrode slurries to a positive current collector [0046]. Both of these layers have the same thickness in order to enhance mechanical strength [0035].
Du teaches possible compositions of the positive active material of the first sublayer [0013] and the positive active material of the second sublayer [0026]. However, Du is silent on the quantitative compressive strength of these two layers. Kuroda and Suhara are analogous art to Du because all teach secondary batteries. Kuroda teaches a positive active material with the composition of Du’s first sub-layer (Kuroda, abstract) and Suhara teaches a composite oxide as a positive active material layer with the composition of Du’s second sub-layer (Suhara, abstract).
Kuroda teaches the usage of “single particles” in their positive active material layer (abstract). Although Kuroda’s disclosure teaches the usage of these particles in combination with other positive active material particles, Kuroda also teaches that these single particles “do not have grain boundaries within the particles and are less prone to particle breakage. This results in less likelihood of generation of a new surface due to particle breakage. This means that possible decomposition reactions with the electrolyte on the new surface are less likely to occur” [0019]. With all of these benefits, 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 these particles by themselves in an active material layer. 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 particles” taught by Kuroda in the first sub-layer of Du to achieve all of the benefits listed above.
Furthermore, these particles have a compressive strength that is 120 MPa or more and 400 MPa or less (Kuroda, [0035]), overlapping with the claimed range of 250 MPa to 400 MPa. 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).
Suhara provides an example of their composite powder that comprises of two granular powders that individually have compression strengths of 87.6 MPa and 25.3 MPa with a mass mixing ratio of 75:25 of the first to second powder (Suhara, column 9, lines 22-42). Taking a weighted average of those compression strengths results in a value of 72 MPa, which is less than 150 MPa.
Lastly, with respect to both Kuroda and Suhara, “[t]he selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945).” See MPEP 2144.07.
Henceforth, the positive electrode that has a first sublayer using the single particles taught by Kuroda (corresponding to the applicant’s first region and first positive electrode active material, respectively) and a second sublayer using the active material taught by Suhara (corresponding to the applicant’s second region and second positive electrode active material, respectively) will be referred to as “modified Du.”
Regarding claims 2 and 10, modified Du’s second positive active material may have a compression strength of 72 MPa which is less than ¾ of 200 MPa, a value near the low end of the range of compression strengths of modified Du’s first positive active material (75% of 200 is 150). The difference between the two compression strengths (200 – 72 = 128) is 128 MPa, which lies within the range recited within claim 10.
Regarding claim 5, modified Du teaches that the outer layer, the first sublayer/region, may have “high mechanical strength” and have a “certain protective effect on the structural stability” of the second sub-layer which is “conducive to the improvement and processing performance of the positive electrode plate” (Du, [0009] and [0010]). Therefore, when manufacturing a positive electrode active material layer with two sub-layers or regions, 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 a first positive active material with a greater compression strength (modified Du’s first positive active material) in the layer further away from the current collector in order to protect the second positive active material (modified Du’s second positive active material) in the layer closer to the current collector.
Regarding claim 6, modified Du’s first positive active material is composed of single particles that have a diameter of 0.5 µm or more (Kuroda, [0067]) and modified Du’s second positive active material is composed of aggregated primary particles that range from 0.5 – 7 µm (Suhara, column 5, lines 29-31). Both of these ranges overlap with the claimed range of “500 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).
Regarding claims 7 and 8, Du’s method of manufacturing the double layered positive electrode involves sequentially applying and drying electrode slurries onto a current collector. First, the slurry comprised of the second positive active material will be applied and dried, and then the slurry comprised of the first positive active material will be applied and dried (Du, [0046]). Therefore, the weight percent of active material in each region/layer will correspond to the weight percent of active material in the slurry. Modified Du’s second positive electrode active material slurry may be 88% active material by weight (Suhara, column 9, lines 45-75), which is greater than 50%. As mentioned above, the positive active material of Kuroda’s disclosure is not solely comprised of the single particles used for modified Du’s first positive active material. However, the process of making said active material involves creating a slurry that consists of lithium metal composite oxide powder and pure water. That slurry is then subjected to a process of “dehydration, separation and drying at 105 °C” [0189]. Since water evaporates at temperatures greater than 100 °C and one of ordinary skill in the art would not expect a finished active material of a battery to be largely comprised of unevaporated water or solid metal-hydroxide byproducts, it would be reasonable to expect that the amount of active material created is much greater than 50%.
Regarding claim 9, modified Du teaches a secondary battery with a positive electrode, a separator, a negative electrode facing the positive electrode and the separator interposed in between, and a liquid electrolyte (Du, abstract, [0042]).
Response to Arguments
Applicant's request for reconsideration of the finality of the rejection of the last Office action is persuasive and, therefore, the finality of that action is withdrawn.
Applicant's arguments filed May 1st, 2026 with respect to claims 1 and 10 have been fully considered but they are not persuasive. The Applicant alleges that using Suhara’s layer and Kuroda’s layer as the second and first layers of Du’s disclosure would impermissibly change the principle of operation of Du. The Examiner would like to point out that the rationale for rejection set forth above does not use Kuroda’s entire layer, just their “single particles”. The Applicant alleges that mixing secondary particles with single particles is essentially in Kuroda, but the Examiner would like to point out to specific portions of Kuroda’s disclosure that support a motivation for using only the “single particles”. Kuroda teaches that “during the use of secondary batteries, a new surface may be generated due to slight cracks at the particle [active material particles in the conventional art] interfaces. The surface of the particles generated as a new surface becomes a reaction site with the electrolyte. In this reaction site, a decomposition reaction of the electrolytic solution occurs, and gas may be generated. The generated gas causes battery swelling (Kuroda, [0008]). Kuroda continues to teach that “the single particles contained in the lithium metal composite oxide powder of the present embodiment have a structure ensuring high particle strength. Such single particles do not have grain boundaries within the particles and are less prone to particle breakage. This results in less likelihood of a generation of a new surface due to particle breakage. This means that possible decomposition reactions with the electrolyte on the new surface are less likely to occur” (Kuroda, [0019]).
Although Kuroda’s disclosure includes a composite oxide that has aggregated secondary particles as well as different primary particles (i.e., the “single particles”), one of ordinary skill in the art would be able to acknowledge the utility and benefits of only using the “single particles” based on Kuroda’s teaching. Usage of these single particles aligns with Du’s teachings of using a single-crystal structure. Therefore, the Examiner’s position is that the usage of Kuroda’s single particles as a sublayer in Du’s disclosure would have been obvious to one of ordinary skill in the art and that Kuroda is an appropriate secondary reference to sustain a rejection over Du.
The Applicant also discusses the claimed difference in compressive strength between the claimed first and second active material particles that is recited in claim 10. The compressive strength of Kuroda’s single particles ranges from 80 – 500 MPa and Suhara’s layer has a compressive strength of 72 MPa. The difference in compressive strengths would range from 8 to 428 MPa, a range that encompasses the claimed range of a difference of 50 MPa and 150 MPa. The Applicant cites scientific reasoning within their specification to demonstrate that a difference in compressive strength outside of the claimed range has negative results. The Examiner, however, respectfully points out that the Applicant does not have experimental data to demonstrate unexpected results that may occur if the difference in compressive strengths is outside of the claimed range. Therefore, a criticality of the range of difference of the two layers’ compressive strengths has not been persuasively established and the range indirectly taught by the prior art still renders the claimed range obvious.
Applicant’s arguments filed May 1st, 2026 with respect to claim 11 is persuasive. The Examiner agrees that the claimed positive electrode active material layer comprising two regions where a first region, having a compressive strength greater than a second region, is closer to the positive electrode current collector is diametrically opposed to the intent of Du’s disclosure. It would be inappropriate to modify Du to fit the claimed structure because such a modification would change Du’s principle of operation.
Allowable Subject Matter
Claim 11 is allowed.
The following is a statement of reasons for the indication of allowable subject matter: claim 11 is drawn to a composite positive active material layer comprised of two sublayers where the sublayer closer to the positive current collector (an “inner” sublayer) has a greater compressive strength than the sublayer farther away from the current collector (an “outer” sublayer). Du, the closest prior art, teaches a composite positive active material layer where the “outer” sublayer has a greater strength than the “inner” sublayer. Du’s intention is for the “outer” layer to have a structural protective effect on the “inner” layer to prevent the “inner” layer from being crushed. Preventing this crushing of particles helps to suppress problematic gas generation that results from crushed particles (Du; [0009]). The present claim has the exact opposite configuration and one of ordinary skill in the art would not be motivated to design such a configuration based on Du and the rest of the state of the prior art.
Conclusion
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 RYAN K BLACKWELL-RUDASILL whose telephone number is (571)270-0563. The examiner can normally be reached Monday - Friday 9:00 a.m. - 5:00 p.m.
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/R.B.R./Examiner, Art Unit 1722
/ANCA EOFF/Primary Examiner, Art Unit 1722
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