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 .
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 2, 4, 5, 8, and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Wook et al. KR-20210099248-A (machine translation provided in office action filed 04/08/2025) in view of Iwasaki US-20140057180-A1.
Regarding Claim 1, Wook discloses a solid-state battery ([0001]) comprising a structure including a positive electrode current collector ([0101]); a positive electrode layer containing a positive electrode active material 10 ([0082]), a first solid electrolyte 20 ([0084], FIG. 2), and a second solid electrolyte 30 ([0097], FIG. 2).
While Wook discloses a suitability of providing a conductive material in the first solid electrolyte 20 ([0090]), exemplified as Super-P, a particulate conductive material ([0118]), and desires to improve electron conductivity from the active material through the solid electrolyte ([0069]) while also ensuring the solid electrolyte coating maintains contact with the positive electrode active material ([0203]), Wook does not indicate the use of a conductive fiber specifically.
Iwasaki, directed to an all-solid-state battery (Iwasaki [0004]) comprising a positive electrode active material 1 ([0030]) similarly coated by a first solid electrolyte 2 (“coat layer”, [0030]), a second solid electrolyte 5 (“sulfide solid electrolyte material”, [0030]), teaches a conductive fiber 3 (“conductive assistant”, [0035]) which is incorporated into the coating of first solid electrolyte 2 (FIG. 1; [0035]). Advantageously, the structure of the conductive fiber provides a conductive path through the first solid electrolyte 2 ([0035, 0039]) without causing the coating of the first solid electrolyte 2 to fall off (Iwasaki FIGS. 2A-2C, Iwasaki [0035]) and thus lose contact with the positive electrode active material.
As such, in seeking to improve the electrical conductivity through Iwasaki’s first solid electrolyte layer and prevent a loss of contact between the positive electrode active material and first solid electrolyte, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to substitute Iwasaki’s particulate conductive material with the conductive fibers taught by Iwasaki. Such a substitution would be made with a reasonable expectation of success as Wook and Iwasaki are directed to similar structures of positive electrode active material particles with an electrolyte coating (Wook FIG. 2, Iwasaki FIG. 1), and because Wook desires to improve electrical conductivity through the first solid electrolyte layer and ensure ability of the layer to maintain contact with the positive electrode active material.
Wook further discloses a solid-state battery comprising a solid electrolyte layer containing a fourth solid electrolyte (Wook [0105], “a solid electrolyte layer”); a negative electrode layer containing a negative electrode active material and a third solid electrolyte ([0105]); and a negative electrode current collector ([0101]), the positive electrode current collector, the positive electrode layer, the solid electrolyte layer, the negative electrode layer, and the negative electrode current collector being stacked in this order ([0105]), wherein the positive electrode layer includes a fiber-containing region that coats the positive electrode active material ([0079]) and that contains the conductive fiber and the first solid electrolyte (Iwasaki [0034]).
Iwasaki only teaches the use of conductive fibers 3 as being particularly advantageous for the coating of the first solid electrolyte 2 (Iwasaki [0029-0030]; FIGs. 2A-2D); thus, an ordinary skilled artisan would not be motivated to substitute the non-fibrous (i.e., particulate) conductive material 40 dispersed in the electrode 100 disclosed by Wook (FIG. 2; [0091], [0098]) with the conductive fibers taught by Iwasaki
In performing the above substitution of conductive material in Wook’s first solid electrolyte 20, one would create a plurality of fiber-free regions that are each located in a gap surrounded by the positive electrode active material 10 coated by the fiber-containing region being the first solid electrolyte 20, the fiber-free regions being free of the conductive fiber and containing the second solid electrolyte 30 as claimed (see Annotated Wook FIG. 2 below).
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Annot. Wook FIG. 2
Wook in view of Iwasaki does not explicitly indicate an amount of the conductive fiber with respect to the total amount of positive electrode active material and first and second solid electrolyte; however, Wook discloses that a ratio of positive electrode active material to first solid electrolyte coating is preferably at least 99:1 (i.e., 1 wt% first solid electrolyte) to improve the rate-limiting characteristics of the material (Wook [0067]), while less than 92:8 (8 wt% first solid electrolyte) to keep the first solid electrolyte coating thin ([0089]), and produces an example positive electrode comprising 77.8 wt% of a composite of first positive electrode active material and first solid electrolyte and 19.5 wt% second solid electrolyte ([0134]). Iwasaki further indicates that a weight ratio of the conductive fibers to the first solid electrolyte is preferably at least 1% to improve the electron conductivity of the coating while less than 5% to maintain the ion conductivity of the first solid electrolyte ([0040]).
As such, in seeking to balance improving the rate-limiting characteristics of modified Wook’s battery and keeping the first positive electrode active material suitably thin according to Wook’s disclosure, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to utilize a range of 1-8 wt% first solid electrolyte in the coated positive electrode active material composite (MPEP 2144.05 II), corresponding to 0.778-6.224 wt% first solid electrolyte in Wook’s example positive electrode. Furthermore, in seeking to balance improving electron conductivity and maintaining ion conductivity of modified Wook’s first solid electrolyte, it would be obvious to utilize a range of 1-5 wt% conductive fiber in the 0.778-6.22 wt% first solid electrolyte of Wook’s positive electrode as taught by Iwasaki (MPEP 2144.05 II). A corresponding amount of conductive fiber relative to a total amount of positive electrode active material, first solid electrolyte, and second solid electrolyte ranges from 0.0077 wt% (1 wt% fiber, 0.778 wt% 1st electrolyte) to 0.311 wt% (5 wt% fiber, 6.22 wt% 1st electrolyte), which overlaps with a portion of the claimed range between 0.05-0.311 mass% of the conductive fiber.
Modified Wook does not explicitly indicate a filling rate of the positive electrode active material, being a ratio of volume occupied by the materials excluding voids between materials to a total volume as being 60% or more or 100% or less. However, Wook discloses a step of compressing the electrode (Wook [0098]), the pressing step being indicated in the instant specification as providing a filling rate of 60% or more or less than 100% (Instant specification, [0043]); as such, one having ordinary skill in the art would expect Wook’s material to inherently have a filling rate of at least 60% and less than 100% (MPEP 2112 III).
Modified Wook does not explicitly disclose that an ion conduction path is secured in an entire thickness direction in an entire thickness direction of the positive electrode layer by the fiber-free regions. However, Wook illustrates an electrode 100 having fiber-free regions comprising the second solid electrolyte 30 having ion conductivity disposed throughout the entirety of the thickness direction of the electrode 100 (Annot. Wook FIG. 3, [0097-0099], [0105]), which is thus interpreted as the ion conduction path secured by the fiber-free regions.
Regarding claim 2, modified Wook discloses the all-solid-state battery of claim 1, wherein a material of the first solid electrolyte is identical to a material of the second solid electrolyte (Machine Translation of Wook [0099]).
Regarding claim 4, modified Wook discloses the all-solid-state battery of claim 1, wherein the fiber-free regions (i.e., the regions not comprised by the positive active material 10 or first electrolyte 20) continuously extend over the positive electrode layer as a whole in the thickness direction of the positive electrode layer (Annot. Wook FIG. 2)
Regarding claim 5, modified Wook discloses the all-solid-state battery of claim 1. While Wook does not explicitly indicate an average fiber diameter of the conductive fiber, Iwasaki teaches that an average fiber diameter of 1-10nm is suitable in order to secure a conductive path through the coating of first electrolyte 2 without causing peeling of the first solid electrolyte 2 (Iwasaki [0035]); it would thus be obvious to select a conductive fiber having an average fiber diameter of 1-10 nm for this purpose (MPEP 2144.07); such a selection would be made with a reasonable expectation of success as Wook discloses a desirability to maintain contact area between the first solid electrolyte and the positive electrode active material (Wook [0203]).
Regarding claim 8, modified Wook discloses the all-solid-state battery of claim 1. Wook further discloses a step where the solvent is removed (Machine Translation of Wook [0073]), and discloses a desirability in avoiding the use of flammable organic solvents to mitigate the risk of ignition (Machine Translation of Wook [0004]). While Wook does not explicitly disclose a maximum allowable content of solvent component as being 50 ppm or less, it would have been obvious to one having ordinary skill in the art before the effective filing date to utilize the claimed range of solvent within the positive electrode layer in the given process of removing solvent disclosed by Wook in an effort to remove flammable solvents and mitigate the risk of ignition.
Regarding claim 9, modified Wook discloses the all-solid-state battery of claim 1, wherein
the conductive fiber is a carbon-based material (“carbon nanotube”, Iwasaki [0034]).
Claims 3 and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Wook in view of Iwasaki as applied to claim 1, and further in view of Watanabe US20210135279A1.
Regarding claim 3, modified Wook discloses the all-solid-state battery of claim 1, wherein the positive electrode layer 100 includes a plurality of regions, each of the plurality of regions includes the gap, the positive electrode active material 10, and the fiber-free region (Annot. Wook FIG. 2). Wook further provides an example embodiment comprising 77.8 wt% of a composite of the first solid electrolyte and positive electrode active material, 19.5% wt% second solid electrolyte, and a remaining 1.3% and 1.4% conductive material and binder ([0134]), the composite comprising mostly (92-99 wt%) positive electrode active material ([0067]). Given the broad claimed range, it is assumed for the purposes of estimation that a weight of positive electrode active material is reasonably equivalent to the composite weight, that a density of the positive electrode active material and electrolytes are the same, and that the binder and conductive material comprise a negligible weight and volume; as such, Wook provides an experimental example with an estimated 19.5 vol% second solid electrolyte being the fiber-free regions, 77.8 vol% positive electrode active material, and the volume occupied by the fiber-free regions is an estimated ¼ times a volume occupied by the positive electrode active material.
Assuming arguendo that Applicant proves modified Wook is incapable of providing a positive electrode layer with a volume occupied by one of the fiber-free regions is 1/45 times or more and 2 times or less a volume occupied by the positive electrode active material, Watanabe teaches an all-solid-state battery with a positive electrode layer 10 (Watanabe [0031], Watanabe FIG. 1), comprising a positive electrode active material 1 and a solid electrolyte 4 (Watanabe [0036], Watanabe FIG. 2). Watanabe further teaches a desirability to optimize the volume ratio of positive electrode active material to solid electrolyte to be between 70/30 to 80/20 respectively, in order to provide a balance between Li-ion conductive paths and positive electrode capacity (Watanabe [0048]). Watanabe does not teach a first and second solid electrolyte but a broadest reasonable interpretation of the electrolyte volume taught by Watanabe would apply to the total volume of first and second solid electrolytes disclosed by Wook as the composition of the two solid electrolytes may be nearly identical (Machine Translation of Wook [0099]); as such, Watanabe’s teachings regarding solid electrolyte volume would be reasonably expected to apply to a combination of first and second solid electrolyte.
Accordingly, it would be obvious for one having ordinary skilled art before the effective filing date of the instant application use a ratio of positive electrode active material to total volume of first and second solid electrolyte between 70/30 to 80/20 as taught by Watanabe in the positive electrode disclosed by Wook in an effort to balance conductive paths and electrode capacity.
Wook does not directly disclose the volume of first solid electrolyte coating on the positive electrode active material particles, but Wook discloses that the diameter of the composite particle does not appreciably increase in the application of first solid electrolyte (Machine Translation of Wook [0169]) which is desirably kept very thin (Machine Translation of Wook [0089]). Given the wide claimed range, it is assumed that the volume occupied by the fiber-containing first solid electrolyte is negligible in comparison to the volume of second solid electrolyte. It is also assumed that the volume of the fiber-free region, comprising mostly second solid electrolyte with a small fraction of binder and conductive material (Machine Translation of Wook [0134]), is roughly equivalent to the volume of second solid electrolyte. Thus, the ratio of positive electrode active material to total volume of first and second solid electrolyte is roughly equivalent to the ratio of positive electrode active material to fiber-free region.
Using the volume ratio of 80/20 to 70/30 for the relation of positive electrode active material to fiber-free region, the volume occupied by the fiber free region is about 1/4 to 3/7 times a volume occupied by the positive electrode active material, which therefore renders this limitation obvious.
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Annotated Wook FIG. 2
Regarding Claim 7, modified Wook discloses the all-solid-state battery of claim 1, but does not teach an all-solid-state battery wherein in the positive electrode layer, a volume ratio of the positive electrode active material to a total amount of the first solid electrolyte and the second solid electrolyte is 70:30 or more and 85:15 or less.
Watanabe, directed to an all-solid-state battery (Watanabe [0031]; [0036], Watanabe FIGs. 1, 2), teaches a desirability to optimize the volume ratio of positive electrode active material to solid electrolyte to be between 70/30 to 80/20, in order to balance between providing Li-ion conductive paths and positive electrode capacity (Watanabe [0048]). Watanabe does not teach a first and second solid electrolyte but a broadest reasonable interpretation of the electrolyte volume taught by Watanabe would apply to the total volume of first and second solid electrolytes disclosed by Wook as the composition of the two solid electrolytes may be nearly identical (Machine Translation of Wook [0099]); as such, Watanabe’s teachings regarding solid electrolyte volume would be reasonably expected to apply to a combination of first and second solid electrolyte.
As such, it would be obvious to one having ordinary skill in the art before the effective filing date of the instant application to use a range of 70/30 to 80/20 for the volume ratio of active material to a total amount of first and second solid electrolytes as taught by Watanabe, which falls within and renders obvious the claimed range, in the positive electrode layer disclosed by Wook to provide a balance between Li-ion conductive paths and positive electrode capacity.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Wook in view of Iwasaki as applied to claim 1, and further in view of Coleman et al. US-20230216058-A1
Regarding claim 6, modified Wook discloses the all-solid-state battery of claim 1. Although Iwasaki, relied upon to teach the selection of conductive fibers in the first solid electrolyte, further indicates a desirability to prevent entanglement of conductive fibers and ensure dispersion of the conductive fibers (Iwasaki [0073]) and to ensure an end of the conductive fiber contacts the positive electrode active material ([0039]), Wook and Iwasaki do not explicitly disclose that an average fiber length of the conductive fiber is 0.1 times or more and 50 times or less an average particle diameter of the positive electrode active material.
Coleman teaches a composite network of conductive fibers in the form of carbon nanotubes formed on the surface of electrode active materials, such as metal oxide particles, which may be used as a cathode (Coleman [0009]) in a solid-state battery ( [0010]). Coleman further teaches that conductive fibers having a ratio of fiber length to active material particle diameter between 1:2 to 1:1 are preferable to ensure uniform dispersion of the conductive fibers and to allow the fibers to wrap around the active material particle surface, ensuring contact between the particles and the fibers. ([0045], [0100]).
As such, in seeking to ensure dispersion of the conductive fibers and contact between the fibers and positive electrode active material particles, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to select conductive fibers having an average fiber length of the conductive fiber being 1-2 times an average particle diameter of the positive electrode active material, which falls within the claimed range of 0.1 times or more and 50 times or less; such a selection would be made with a reasonable expectation of success as Coleman teaches a suitability of this length of conductive fiber for this purpose (MPEP 2144.07)
Response to Arguments
Applicant notes that Watanabe US20210135279 was omitted from the form PTO-892 of the previous nonfinal office action filed 04/08/2025. An updated PTO-892 citing Watanabe is provided in this office communication.
Applicant's arguments filed 08/08/2025 have been fully considered but they are not persuasive for the reasons below.
Applicant asserts that Wook in view of Iwasaki fails to disclose an ion conduction path is secured in an entire thickness direction of the positive electrode layer by the fiber-free regions, the fiber-free regions extending from one end to the other end in the thickness direction of the positive electrode layer as recited in claim 1 (Remarks pp. 5-6).
While this argument has been considered, it has not been found persuasive, as the arguments do not specifically point out how this feature is patentably distinguished from the disclosure of Wook or Wook in view of Iwasaki.
Applicant asserts that Wook, which does not disclose the use of conductive fibers, and Iwasaki, which discloses a range of conductive fibers outside the claimed range, fail to disclose claim 1 as amended to further recite an amount of conductive fiber is 0.05 mass% or more and 1 mass% or less with respect to a total amount of positive electrode active material and first and solid electrolyte (Remarks pp. 6-7).
While this argument has been fully considered, it has not been found persuasive because the weight content of Wook’s positive electrode active material and first and second electrolytes and the weight content of the conductive fibers may be optimized in view of Wook and Iwasaki’s teachings such that one having ordinary skill in the art would utilize a range of conductive fiber mass between 0.0077 mass% to 0.311 mass%; see discussion of claim 1 pp. 4-5 of this office action.
Applicant asserts that Wook does not disclose the claimed feature of a filling rate of the positive electrode layer between 60%-100%, being the ratio of volume occupied by the materials excluding voids between materials to a total volume of the layer (Remarks pp. 7).
While this argument has been fully considered, it has not been found persuasive because Wook discloses a step of compressing the positive electrode, which, according to applicant disclosure, would inherently provide the claimed structure of a filling rate between 60% to 100%; see pp. 5 of this office action.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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.
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/E.C./Examiner, Art Unit 1751
/JONATHAN G LEONG/Supervisory Patent Examiner, Art Unit 1751 9/26/2025