DETAILED ACTION
Response to Amendment
In the amendment dated 9/4/26, the following has occurred: Claim 1 has been amended.
Claims 1-12 are pending. Claims 1-10 are examined in this office action. This communication is a Final Rejection in response to the "Amendment" and "Remarks" filed on 9/4/26.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim Rejections - 35 USC § 103
Claims 1 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over WO 2018/175465 A1 (WO'465) in view of WO 2007/116718 A1 (WO'718).
As to Claim 1:
WO'465 discloses a method for producing a secondary battery electrode using a non-aqueous electrolyte (WO'465, Pgs. 2, 5–7), comprising: (1) preparing a composition for producing an electrode substantially free of a liquid medium by using a binder that is a powder which is composed of a composition essentially including a polytetrafluoroethylene resin and a conductive aid and which is free of an active material (WO'465 discloses combining polymeric binder particles comprising polytetrafluoroethylene (PTFE) with an ionically insulating coating material comprising conductive carbon in the absence of active material, mixing them to form coated/composite binder particles free of active material, and combining the coated binder particles with active material particles such as graphite or NMC in a dry, solvent-free process substantially free of liquid medium or solvents; WO'465, Pgs. 2, 4–7, 9, 17); (2) applying shear stress while mixing to the composition in solvent content of 10% mass or less relative to the composition to obtain an electrode mixture (WO'465 discloses milling the mixture of active material particles and composite binder particles in a solvent-free state, corresponding to 0% solvent mass, using a high-shear process such as jet-milling at a shear velocity sufficient to fibrillize the PTFE binder particles to form an electrode film mixture; WO'465, Pgs. 2, 5–7, 9, 17); and rolling the electrode mixture into a sheet shape (WO'465 discloses calendering the electrode film mixture to form a free-standing, self-supporting electrode film; WO'465, Pgs. 2, 5, 7, 10, 17).
However, WO'465 does not explicitly disclose preparing the composition into a sheet during the mixing step (2), forming the electrode mixture obtained in (2) into a bulk shape (step (3)), and rolling the bulk-shape electrode mixture obtained in (3) into a sheet shape (step (4)), because WO'465 feeds the jet-milled powder mixture directly to a calender to form the electrode film without an intermediate bulk shaping step (WO'465, Pgs. 2, 9, 17).
WO'718 discloses dry molding methods for manufacturing an electrode for an electrochemical element, such as a lithium ion secondary battery, from dry particulate electrode materials comprising an active material, a conductive material, and a fibrillizable polytetrafluoroethylene (PTFE) binder (WO'718, Pgs. 2, 5, 10, 11). Specifically, WO'718 teaches that dry molding methods include forming the electrode mixture by extrusion molding (also referred to as paste extrusion) to form an extruded bulk mass, or by filling the electrode material into a mold and pressing and molding in a mold (thereby forming the electrode mixture into a bulk shape as in step (3)), and subsequently post-pressing or rolling the molded bulk-shape electrode mixture into a sheet shape using a roll pressing process with two cylindrical rolls (step (4)) (WO'718, Pg. 10). Furthermore, to the extent that step (2) recites preparing the composition into a sheet by applying shear stress while mixing, WO'718 teaches that dry extrusion molding subjects the material to shear while forming it into an extruded film/sheet, which can be further rolled or post-pressed between rolls to achieve uniform thickness and high density (WO'718, Pg. 10).
WO'465 and WO'718 are analogous arts because both references are from the same field of endeavor, namely the manufacture of dry-processed electrodes for electrochemical energy storage devices including lithium ion secondary batteries using non-aqueous electrolytes, and both references are reasonably pertinent to the particular problem of processing and forming fibrillatable PTFE-containing powder mixtures into durable, uniform, free-standing electrode sheets without relying on liquid processing solvents (WO'465, Pgs. 2, 5–7; WO'718, Pgs. 2, 5, 10, 11).
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to combine the dry-compounded, active-material-free PTFE and conductive carbon binder composition and high-shear jet-milling process of WO'465 with the intermediate bulk shaping (such as paste extrusion or mold pressing) and subsequent roll-pressing steps taught by WO'718, in order to compact and consolidate the aerated, sheared powder mixture into an intermediate bulk form prior to final roll pressing, thereby preventing powder spillage, ensuring continuous and uniform feeding into the roll press, and eliminating variations in electrode sheet thickness to achieve high capacitance and density as taught by WO'718 (WO'718, Pg. 10; WO'465, Pgs. 2, 9).
As to Claim 8:
WO'465 discloses the method for producing a secondary battery electrode according to claim 1 (see the rejection of claim 1); and wherein the secondary battery is a lithium ion secondary battery (WO'465 discloses that the energy storage device can be a lithium ion battery, such as a lithium-cobalt, lithium-manganese, lithium iron phosphate, lithium nickel manganese cobalt oxide, lithium nickel cobalt aluminum oxide, lithium titanate, or lithium sulfur battery; WO'465, Pgs. 2, 5, 6, 7).
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over WO 2018/175465 A1 (WO'465) in view of WO 2007/116718 A1 (WO'718), as applied to Claim 1 above, and further in view of Li et al. , “Evaluation Residual Moisture in Lithium-Ion Battery Electrodes and Its Effect on Electrode Perforamnce”, Pg 1029-1035 (Li).
As to Claim 2:
WO'465 discloses the method for producing a secondary battery electrode according to claim 1 (see the rejection of claim 1; WO'465, Pgs. 2, 4–7, 9, 10, 17); and provides the binder as a dry powder (WO'465, Pgs. 2, 8, 9).
However, as set forth in the rejection of claim 1, WO'465 does not explicitly disclose preparing the composition into a sheet during the mixing step (2), forming the electrode mixture obtained in (2) into a bulk shape (step (3)), and rolling the bulk-shape electrode mixture obtained in (3) into a sheet shape (step (4)) (WO'465, Pgs. 2, 9, 17). Furthermore, WO'465 does not explicitly disclose that the binder has a moisture content of 1,000 ppm or less.
WO'718 discloses dry molding methods for manufacturing an electrode for an electrochemical element, such as a lithium ion secondary battery, from dry particulate electrode materials comprising an active material, a conductive material, and a fibrillizable polytetrafluoroethylene (PTFE) binder (WO'718, Pgs. 2, 5, 10, 11). Specifically, WO'718 teaches forming the electrode mixture into a bulk shape (step (3)) by extrusion molding (paste extrusion) into an extruded mass or by mold pressing, and subsequently rolling or post-pressing the bulk-shape electrode mixture into a sheet shape using a roll pressing process with two cylindrical rolls (step (4)) (WO'718, Pg. 10). Furthermore, to the extent that step (2) recites preparing the composition into a sheet by applying shear stress while mixing, WO'718 teaches that dry extrusion molding subjects the material to shear while forming it into an extruded film/sheet, which can be further rolled or post-pressed between rolls to achieve uniform thickness and high density (WO'718, Pg. 10). Additionally, Li discloses evaluating, measuring, and controlling residual moisture in lithium-ion battery electrodes and materials using Karl Fischer coulometry (Li, Pgs. 1029–1034). Specifically, Li teaches that removing residual moisture is essential for battery performance because residual water decomposes during charging and lowers first-cycle coulombic efficiency (Li, Pgs. 1029, 1030, 1033). Li discloses drying battery electrodes and materials using secondary vacuum drying at 80°C to 120°C to reduce residual moisture levels to 242 ppm, 160 ppm, 87 ppm, and 47 ppm (Li, Pgs. 1031–1032), and explicitly teaches that residual moisture content above 500 ppm results in rapid capacity degradation (Li, Pgs. 1033–1034).
WO'465, WO'718, and Li are analogous arts because each reference is from the same field of endeavor, namely the fabrication and processing of electrodes for lithium-ion secondary batteries, and each reference is reasonably pertinent to the particular problems of dry-processing fibrillatable PTFE electrode mixtures into uniform sheets and eliminating residual moisture to prevent electrochemical decomposition and capacity fading in non-aqueous battery cells (WO'465, Pgs. 2, 5–7; WO'718, Pgs. 2, 5, 10, 11; Li, Pgs. 1029–1034).
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to combine the dry-compounded, active-material-free PTFE and conductive carbon binder composition and high-shear jet-milling process of WO'465 with the intermediate bulk shaping and rolling steps taught by WO'718, and further to dry the binder and electrode materials to maintain a moisture content of 1,000 ppm or less (specifically below 500 ppm, such as 47 to 242 ppm) as taught by Li, in order to consolidate the sheared powder into a bulk form for uniform, continuous feeding into a roll press while eliminating moisture-induced electrolyte breakdown and active material capacity fading, thereby ensuring high first-cycle coulombic efficiency and long cycle life as taught by Li (WO'718, Pg. 10; Li, Pgs. 1029, 1032–1034; WO'465, Pgs. 2, 9).
Claims 3-4 are rejected under 35 U.S.C. 103 as being unpatentable over WO 2018/175465 A1 (WO'465) in view of WO 2007/116718 A1 (WO'718), as applied to Claim 1 above, and further in view of JP H113709 A (JP'709).
As to Claim 3:
WO'465 discloses the method for producing a secondary battery electrode according to claim 1 (see the rejection of claim 1; WO'465, Pgs. 2, 4–7, 9, 10, 17); and discloses that the binder is a powder which is composed of a composition essentially including a polytetrafluoroethylene resin and a conductive aid and which is free of an active material (WO'465, Pgs. 2, 4–7, 9, 17).
However, as set forth in the rejection of claim 1, WO'465 does not explicitly disclose preparing the composition into a sheet during the mixing step (2), forming the electrode mixture obtained in (2) into a bulk shape (step (3)), and rolling the bulk-shape electrode mixture obtained in (3) into a sheet shape (step (4)) (WO'465, Pgs. 2, 9, 17). Furthermore, WO'465 does not explicitly disclose that the binder is produced by a production method comprising (A) mixing a polytetrafluoroethylene resin and a conductive aid in the presence of a liquid medium, as WO'465 forms the coated binder particles by dry mixing or milling (WO'465, Pgs. 2, 8, 9).
WO'718 discloses dry molding methods for manufacturing an electrode for an electrochemical element, such as a lithium ion secondary battery, from dry particulate electrode materials comprising an active material, a conductive material, and a fibrillizable polytetrafluoroethylene (PTFE) binder (WO'718, Pgs. 2, 5, 10, 11). Specifically, WO'718 teaches forming the electrode mixture into a bulk shape (step (3)) by extrusion molding (paste extrusion) into an extruded mass or by mold pressing, and subsequently rolling or post-pressing the bulk-shape electrode mixture into a sheet shape using a roll pressing process with two cylindrical rolls (step (4)) (WO'718, Pg. 10). Furthermore, to the extent that step (2) recites preparing the composition into a sheet by applying shear stress while mixing, WO'718 teaches that dry extrusion molding subjects the material to shear while forming it into an extruded film/sheet, which can be further rolled or post-pressed between rolls to achieve uniform thickness and high density (WO'718, Pg. 10). Additionally, JP'709 discloses producing an electrode for a lithium secondary battery using a polytetrafluoroethylene-containing binder powder that is free of active material (JP'709, Pgs. 1, 4, 7, 10). Specifically, JP'709 teaches that the binder powder is produced by a production method comprising step (A) adding and mixing at least an electron conduction auxiliary agent (such as flake graphite, acetylene black, or carbon black) excluding the positive electrode active material into an aqueous dispersion of polytetrafluoroethylene in the presence of a liquid medium (water) using a planetary mixer or kneader, and subsequently drying the mixture to prepare the polytetrafluoroethylene-containing binder powder (JP'709, Pgs. 1, 4, 7, 10).
WO'465, WO'718, and JP'709 are analogous arts because each reference is from the same field of endeavor, namely the manufacture of electrodes for lithium secondary batteries using non-aqueous electrolytes, and each reference is reasonably pertinent to the particular problem of preparing homogeneous, fibrillatable PTFE and conductive carbon binder compositions and forming them into uniform, high-strength electrode sheets (WO'465, Pgs. 2, 5–7; WO'718, Pgs. 2, 5, 10, 11; JP'709, Pgs. 1–4).
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to combine the dry-compounded, active-material-free PTFE and conductive carbon binder composition and high-shear jet-milling process of WO'465 with the intermediate bulk shaping and rolling steps taught by WO'718, and further to produce the composite PTFE and conductive aid binder powder by mixing an aqueous dispersion of PTFE with the conductive aid in the presence of a liquid medium (water) prior to drying as taught by JP'709, in order to allow the conductive particles to disperse uniformly between the primary PTFE particles to prevent premature PTFE fibril entanglement and clumping during initial binder handling as taught by JP'709, while consolidating the sheared electrode mixture into a bulk shape to ensure continuous and uniform feeding into a roll press to obtain a high-density, defect-free electrode sheet as taught by WO'718 (WO'718, Pg. 10; JP'709, Pgs. 3, 4, 7; WO'465, Pgs. 2, 9).
As to Claim 4:
WO'465 discloses the method for producing a secondary battery electrode according to claim 3 (see the rejection of claim 3; WO'465, Pgs. 2, 4–7, 9, 10, 17); and discloses that the binder is a powder which is composed of a composition essentially including a polytetrafluoroethylene resin and a conductive aid and which is free of an active material (WO'465, Pgs. 2, 4–7, 9, 17).
However, as set forth in the rejections of claims 1 and 3, WO'465 does not explicitly disclose preparing the composition into a sheet during the mixing step (2), forming the electrode mixture obtained in (2) into a bulk shape (step (3)), and rolling the bulk-shape electrode mixture obtained in (3) into a sheet shape (step (4)) (WO'465, Pgs. 2, 9, 17). Furthermore, WO'465 does not explicitly disclose that the binder is produced by a production method comprising (A) mixing a polytetrafluoroethylene resin and a conductive aid in the presence of a liquid medium, and wherein the liquid medium is water, as WO'465 forms the coated binder particles by dry mixing or milling (WO'465, Pgs. 2, 8, 9).
WO'718 discloses dry molding methods for manufacturing an electrode for an electrochemical element, such as a lithium ion secondary battery, from dry particulate electrode materials comprising an active material, a conductive material, and a fibrillizable polytetrafluoroethylene (PTFE) binder (WO'718, Pgs. 2, 5, 10, 11). Specifically, WO'718 teaches forming the electrode mixture into a bulk shape (step (3)) by extrusion molding (paste extrusion) into an extruded mass or by mold pressing, and subsequently rolling or post-pressing the bulk-shape electrode mixture into a sheet shape using a roll pressing process with two cylindrical rolls (step (4)) (WO'718, Pg. 10). Furthermore, to the extent that step (2) recites preparing the composition into a sheet by applying shear stress while mixing, WO'718 teaches that dry extrusion molding subjects the material to shear while forming it into an extruded film/sheet, which can be further rolled or post-pressed between rolls to achieve uniform thickness and high density (WO'718, Pg. 10). Additionally, JP'709 discloses producing a polytetrafluoroethylene-containing binder powder free of active material for a lithium secondary battery electrode (JP'709, Pgs. 1, 4, 7, 10). Specifically, JP'709 teaches that the binder is produced by a production method comprising step (A) adding and mixing at least an electron conduction auxiliary agent (such as flake graphite, acetylene black, or carbon black) excluding the positive electrode active material into an aqueous dispersion of polytetrafluoroethylene in the presence of a liquid medium, wherein the liquid medium is water, and subsequently drying the mixture to prepare the polytetrafluoroethylene-containing binder powder (JP'709, Pgs. 1, 2, 4, 7, 10).
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to combine the dry-compounded, active-material-free PTFE and conductive carbon binder composition and high-shear jet-milling process of WO'465 with the intermediate bulk shaping and rolling steps taught by WO'718, and further to produce the composite PTFE and conductive aid binder powder by mixing an aqueous dispersion of PTFE with the conductive aid in the presence of a liquid medium, wherein the liquid medium is water, prior to drying as taught by JP'709, in order to utilize readily available commercial aqueous PTFE dispersions while avoiding flammable or toxic organic solvents, and allowing the conductive particles to disperse uniformly between the primary PTFE particles in water to prevent premature PTFE fibril entanglement and clumping during initial binder handling as taught by JP'709, while consolidating the sheared electrode mixture into a bulk shape to ensure continuous and uniform feeding into a roll press to obtain a high-density, defect-free electrode sheet as taught by WO'718 (WO'718, Pg. 10; JP'709, Pgs. 1, 2, 4, 7; WO'465, Pgs. 2, 9).
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over WO 2018/175465 A1 (WO'465) in view of WO 2007/116718 A1 (WO'718) and JP H113709 A (JP'709), as applied to Claim 1, and further in view of JP 2008243767 A (JP'767).
As to Claim 5:
WO'465 discloses the method for producing a secondary battery electrode according to claim 3 (see the rejection of claim 3; WO'465, Pgs. 2, 4–7, 9, 10, 17); and discloses that the binder is a powder which is composed of a composition essentially including a polytetrafluoroethylene resin and a conductive aid and which is free of an active material (WO'465, Pgs. 2, 4–7, 9, 17).
However, as set forth in the rejections of claims 1 and 3, WO'465 does not explicitly disclose preparing the composition into a sheet during the mixing step (2), forming the electrode mixture obtained in (2) into a bulk shape (step (3)), and rolling the bulk-shape electrode mixture obtained in (3) into a sheet shape (step (4)) (WO'465, Pgs. 2, 9, 17). Furthermore, WO'465 does not explicitly disclose that the binder is produced by a production method comprising (A) mixing a polytetrafluoroethylene resin and a conductive aid in the presence of a liquid medium, and (B) drying the composition obtained in step (A) by spray drying, as WO'465 forms the coated binder particles by dry mixing or milling (WO'465, Pgs. 2, 8, 9).
WO'718 discloses dry molding methods for manufacturing an electrode for an electrochemical element, such as a lithium ion secondary battery, from dry particulate electrode materials comprising an active material, a conductive material, and a fibrillizable polytetrafluoroethylene (PTFE) binder (WO'718, Pgs. 2, 5, 10, 11). Specifically, WO'718 teaches forming the electrode mixture into a bulk shape (step (3)) by extrusion molding (paste extrusion) into an extruded mass or by mold pressing, and subsequently rolling or post-pressing the bulk-shape electrode mixture into a sheet shape using a roll pressing process with two cylindrical rolls (step (4)) (WO'718, Pg. 10). Furthermore, to the extent that step (2) recites preparing the composition into a sheet by applying shear stress while mixing, WO'718 teaches that dry extrusion molding subjects the material to shear while forming it into an extruded film/sheet, which can be further rolled or post-pressed between rolls to achieve uniform thickness and high density (WO'718, Pg. 10). Additionally, JP'709 discloses producing a polytetrafluoroethylene-containing binder powder free of active material for a lithium secondary battery electrode by a production method comprising step (A) adding and mixing at least an electron conduction auxiliary agent (such as flake graphite, acetylene black, or carbon black) excluding the positive electrode active material into an aqueous dispersion of polytetrafluoroethylene in the presence of a liquid medium (water) using a mixer, and subsequently drying the mixture to prepare the polytetrafluoroethylene-containing binder powder (JP'709, Pgs. 1, 4, 7, 10). Furthermore, JP'767 discloses preparing a powder composed of polytetrafluoroethylene and carbon black free of active material by a method comprising mixing carbon black powder and a PTFE dispersion to obtain a uniform slurry in a liquid medium (step (A)), and drying the resulting composition by spray drying to obtain a uniform, spherical powder having a median particle size in the range of 2 µm to 100 µm (step (B)) (JP'767, Pgs. 2, 4, 7, 11).
WO'465, WO'718, JP'709, and JP'767 are analogous arts because WO'465, WO'718, and JP'709 are each from the same field of endeavor, namely the manufacture of electrodes for lithium secondary batteries using non-aqueous electrolytes, and each of WO'465, WO'718, JP'709, and JP'767 is reasonably pertinent to the particular problem of preparing homogeneous, free-flowing composite powder mixtures comprising fibrillatable PTFE and conductive carbon and processing them into uniform, high-strength electrode layers (WO'465, Pgs. 2, 5–7; WO'718, Pgs. 2, 5, 10, 11; JP'709, Pgs. 1–4; JP'767, Pgs. 2, 4).
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to combine the dry-compounded, active-material-free PTFE and conductive carbon binder composition and high-shear jet-milling process of WO'465 with the intermediate bulk shaping and rolling steps taught by WO'718, and to produce the composite PTFE and conductive aid binder powder by mixing in a liquid medium as taught by JP'709, and further to dry the liquid mixture of PTFE and conductive aid by spray drying as taught by JP'767, in order to rapidly convert the liquid slurry into dry, uniform, substantially spherical composite particles having excellent fluidity and handling characteristics without thermal degradation as taught by JP'767, while allowing the conductive particles to disperse uniformly between the primary PTFE particles to prevent premature fibril entanglement during binder preparation as taught by JP'709, and consolidating the sheared electrode mixture into a bulk shape to ensure continuous and uniform feeding into a roll press to obtain a high-density, defect-free electrode sheet as taught by WO'718 (WO'718, Pg. 10; JP'709, Pgs. 3, 4, 7; JP'767, Pgs. 2, 4, 7; WO'465, Pgs. 2, 9).
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over WO 2018/175465 A1 (WO'465) in view of WO 2007/116718 A1 (WO'718), as applied to Claim 1 above, and further in view of JP 2008243767 A (JP'767).
As to Claim 10:
WO'465 discloses the method for producing a secondary battery electrode according to claim 1 (see the rejection of claim 1; WO'465, Pgs. 2, 4–7, 9, 10, 17); and discloses that the binder is a powder which is composed of a composition essentially including a polytetrafluoroethylene resin and a conductive aid and which is free of an active material, wherein the conductive carbon is present in an amount of about 1% to 50% (such as 5% to 20%) relative to the mass of the PTFE binder particles (WO'465, Pgs. 2, 5, 9, 17).
However, as set forth in the rejection of claim 1, WO'465 does not explicitly disclose preparing the composition into a sheet during the mixing step (2), forming the electrode mixture obtained in (2) into a bulk shape (step (3)), and rolling the bulk-shape electrode mixture obtained in (3) into a sheet shape (step (4)) (WO'465, Pgs. 2, 9, 17). Furthermore, while WO'465 discloses combining PTFE and conductive carbon in proportions of 1% to 50% carbon relative to the mass of PTFE, WO'465 does not explicitly disclose that the binder has an element ratio of fluorine to carbon (F/C ratio) of 0.4 or more and 3.0 or less as measured by elemental analysis.
WO'718 discloses dry molding methods for manufacturing an electrode for an electrochemical element, such as a lithium ion secondary battery, from dry particulate electrode materials comprising an active material, a conductive material, and a fibrillizable polytetrafluoroethylene (PTFE) binder (WO'718, Pgs. 2, 5, 10, 11). Specifically, WO'718 teaches forming the electrode mixture into a bulk shape (step (3)) by extrusion molding (paste extrusion) into an extruded mass or by mold pressing, and subsequently rolling or post-pressing the bulk-shape electrode mixture into a sheet shape using a roll pressing process with two cylindrical rolls (step (4)) (WO'718, Pg. 10). Furthermore, to the extent that step (2) recites preparing the composition into a sheet by applying shear stress while mixing, WO'718 teaches that dry extrusion molding subjects the material to shear while forming it into an extruded film/sheet, which can be further rolled or post-pressed between rolls to achieve uniform thickness and high density (WO'718, Pg. 10). Additionally, JP'767 discloses preparing a powder composition consisting of polytetrafluoroethylene and carbon black conductive aid free of active material, wherein the carbon black and PTFE are mixed at a specific solid content ratio of carbon black to PTFE of 6/4 (40% PTFE and 60% carbon black) (JP'767, Pgs. 2, 4, 7, 11). In such a PTFE and carbon black composition, the elemental ratio of fluorine to carbon (F/C ratio) inherently falls within the range of 0.4 or more and 3.0 or less (specifically, an F/C ratio of approximately 0.44).
WO'465, WO'718, and JP'767 are analogous arts because WO'465 and WO'718 are each from the same field of endeavor, namely the manufacture of dry-processed electrodes for electrochemical devices such as lithium secondary batteries using non-aqueous electrolytes, and each of WO'465, WO'718, and JP'767 is reasonably pertinent to the particular problem of preparing homogeneous, free-flowing composite powder mixtures comprising fibrillatable PTFE and conductive carbon with balanced electrical conductivity and binding strength, and processing them into uniform, high-strength electrode sheets (WO'465, Pgs. 2, 5–7; WO'718, Pgs. 2, 5, 10, 11; JP'767, Pgs. 2, 4).
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to combine the dry-compounded, active-material-free PTFE and conductive carbon binder composition and high-shear jet-milling process of WO'465 with the intermediate bulk shaping and rolling steps taught by WO'718, and further to select the proportion of PTFE and conductive carbon to provide an elemental fluorine to carbon (F/C) ratio of 0.4 or more and 3.0 or less as taught by JP'767 and WO'465, in order to balance electronic conductivity and binder cohesive strength within the electrode while consolidating the sheared electrode mixture into a bulk shape to ensure continuous and uniform feeding into a roll press to obtain a high-density, defect-free electrode sheet as taught by WO'718 (WO'718, Pg. 10; JP'767, Pgs. 2, 7; WO'465, Pgs. 2, 5, 9).
Claims 6 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over WO 2018/175465 A1 (WO'465) in view of WO 2007/116718 A1 (WO'718), as applied to Claim 1 above, and further in view of EP 0735093 A1 (EP'093).
As to Claim 6:
WO'465 discloses the method for producing a secondary battery electrode according to claim 1 (see the rejection of claim 1; WO'465, Pgs. 2, 4–7, 9, 10, 17); and discloses that the binder comprises a fibrillizable polytetrafluoroethylene (PTFE) resin (WO'465, Pgs. 2, 5, 7, 8, 17).
However, as set forth in the rejection of claim 1, WO'465 does not explicitly disclose preparing the composition into a sheet during the mixing step (2), forming the electrode mixture obtained in (2) into a bulk shape (step (3)), and rolling the bulk-shape electrode mixture obtained in (3) into a sheet shape (step (4)) (WO'465, Pgs. 2, 9, 17). Furthermore, WO'465 does not explicitly disclose that the polytetrafluoroethylene resin has a standard specific gravity of 2.11 to 2.20.
WO'718 discloses dry molding methods for manufacturing an electrode for an electrochemical element, such as a lithium ion secondary battery, from dry particulate electrode materials comprising an active material, a conductive material, and a fibrillizable polytetrafluoroethylene (PTFE) binder (WO'718, Pgs. 2, 5, 10, 11). Specifically, WO'718 teaches forming the electrode mixture into a bulk shape (step (3)) by extrusion molding (paste extrusion) into an extruded mass or by mold pressing, and subsequently rolling or post-pressing the bulk-shape electrode mixture into a sheet shape using a roll pressing process with two cylindrical rolls (step (4)) (WO'718, Pg. 10). Furthermore, to the extent that step (2) recites preparing the composition into a sheet by applying shear stress while mixing, WO'718 teaches that dry extrusion molding subjects the material to shear while forming it into an extruded film/sheet, which can be further rolled or post-pressed between rolls to achieve uniform thickness and high density (WO'718, Pg. 10). Additionally, EP'093 discloses a binder for non-aqueous electrolyte lithium secondary battery electrodes comprising fibrillating polytetrafluoroethylene (PTFE) resin (EP'093, Pgs. 2, 3, 6, 8, 9). Specifically, EP'093 teaches that the fibrillating PTFE resin has a standard specific gravity (measured according to ASTM D-1457) of up to 2.210, preferably 2.200 to 2.130 (which falls within the claimed range of 2.11 to 2.20), and explicitly exemplifies a fibrillating PTFE powder having a standard specific gravity of 2.180 that exhibits excellent paste extrudability and elongation (EP'093, Pgs. 3, 8). EP'093 further explains that maintaining the standard specific gravity within this range is critical because an SSG greater than 2.210 results in lower molecular weight where the polymer is less likely to fibrillate, whereas an SSG less than 2.130 represents an excessively high molecular weight that is difficult to produce (EP'093, Pg. 3).
WO'465, WO'718, and EP'093 are analogous arts because each reference is from the same field of endeavor, namely the manufacture of electrodes for lithium secondary batteries using non-aqueous electrolytes, and each reference is reasonably pertinent to the particular problem of selecting and processing fibrillatable PTFE binders having suitable physical properties and molecular weights to facilitate fibril formation and provide sufficient mechanical strength when forming dry electrode sheets (WO'465, Pgs. 2, 5–7; WO'718, Pgs. 2, 5, 10, 11; EP'093, Pgs. 2–4, 8, 9).
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to combine the dry-compounded, active-material-free PTFE and conductive carbon binder composition and high-shear jet-milling process of WO'465 with the intermediate bulk shaping and rolling steps taught by WO'718, and further to select a polytetrafluoroethylene resin having a standard specific gravity within the range of 2.11 to 2.20 (such as 2.180) as taught by EP'093, in order to ensure that the PTFE resin possesses sufficient molecular weight to readily fibrillate under shear stress and impart high tensile strength and elongation to the electrode sheet while avoiding unworkable polymers that are difficult to produce as taught by EP'093, and consolidating the sheared electrode mixture into a bulk shape to ensure continuous and uniform feeding into a roll press to obtain a high-density, defect-free electrode sheet as taught by WO'718 (WO'718, Pg. 10; EP'093, Pgs. 3, 8; WO'465, Pgs. 2, 5, 9).
As to Claim 9:
WO'465 discloses the method for producing a secondary battery electrode according to claim 1 (see the rejection of claim 1; WO'465, Pgs. 2, 4–7, 9, 10, 17); and discloses that the polytetrafluoroethylene resin has a fibrous structure in the secondary battery electrode (WO'465 discloses applying high shear stress via jet-milling at a shear velocity sufficient to physically fibrillize the PTFE binder particles into a network or matrix of thin web-like fibers and fibrils that enmesh and support the active material particles to form a self-supporting electrode film; WO'465, Pgs. 2, 5, 7, 9, 17).
However, as set forth in the rejection of claim 1, WO'465 does not explicitly disclose preparing the composition into a sheet during the mixing step (2), forming the electrode mixture obtained in (2) into a bulk shape (step (3)), and rolling the bulk-shape electrode mixture obtained in (3) into a sheet shape (step (4)) (WO'465, Pgs. 2, 9, 17). Furthermore, WO'465 does not explicitly disclose that the polytetrafluoroethylene resin has a fibril diameter (median value) in the secondary battery electrode of 20 nm or more.
WO'718 discloses dry molding methods for manufacturing an electrode for an electrochemical element, such as a lithium ion secondary battery, from dry particulate electrode materials comprising an active material, a conductive material, and a fibrillizable polytetrafluoroethylene (PTFE) binder (WO'718, Pgs. 2, 5, 10, 11). Specifically, WO'718 teaches forming the electrode mixture into a bulk shape (step (3)) by extrusion molding (paste extrusion) into an extruded mass or by mold pressing, and subsequently rolling or post-pressing the bulk-shape electrode mixture into a sheet shape using a roll pressing process with two cylindrical rolls (step (4)) (WO'718, Pg. 10). Furthermore, to the extent that step (2) recites preparing the composition into a sheet by applying shear stress while mixing, WO'718 teaches that dry extrusion molding subjects the material to shear while forming it into an extruded film/sheet, which can be further rolled or post-pressed between rolls to achieve uniform thickness and high density (WO'718, Pg. 10). Additionally, EP'093 discloses an electrode for a non-aqueous electrolyte lithium secondary battery comprising active material, conductive carbon, and fibrillating polytetrafluoroethylene (PTFE) resin (EP'093, Pgs. 2, 3, 6, 8–10). Specifically, EP'093 teaches that when compressive shearing force is applied to an electrode composition containing PTFE, the PTFE resin readily fibrillates to form thin fibrils that interlock the powder particles into a cohesive sheet, and EP'093 explicitly discloses in Figure 2 a scanning electron microscope photograph at 10,000x magnification illustrating the resulting fibrous structure, wherein the fibrillated PTFE fibrils interconnecting the electrode particles inherently possess diameters well in excess of 20 nm (EP'093, Pgs. 2, 6, 9).
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to combine the dry-compounded, active-material-free PTFE and conductive carbon binder composition and high-shear jet-milling process of WO'465 with the intermediate bulk shaping and rolling steps taught by WO'718, and to carry out the shear fibrillation of the PTFE binder as taught by WO'465 and EP'093 to form a fibrous structure having a fibril diameter of 20 nm or more as demonstrated in EP'093, because subjecting fibrillatable PTFE particles to compressive shear forces predictably stretches the polymer into an interlocking fibrous network of fibrils having widths of 20 nm or more to securely bind and support the electrode particles as shown in EP'093, while consolidating the sheared electrode mixture into a bulk shape ensures continuous and uniform feeding into a roll press to obtain a high-density, defect-free electrode sheet as taught by WO'718 (WO'718, Pg. 10; EP'093, Pgs. 2, 6, 9; WO'465, Pgs. 2, 5, 7, 9).
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over WO 2018/175465 A1 (WO'465) in view of WO 2007/116718 A1 (WO'718), as applied to Claim 1 above, and further in view of KR 20190051354 A (KR'354).
As to Claim 7:
WO'465 discloses the method for producing a secondary battery electrode according to claim 1 (see the rejection of claim 1; WO'465, Pgs. 2, 4–7, 9, 10, 17); and discloses that the composition for producing an electrode includes a positive electrode active material (WO'465 discloses that an energy storage device cathode includes cathode active material particles, such as a lithium transition metal oxide including lithium nickel manganese cobalt oxide (NMC), lithium manganese oxide (LMO), lithium iron phosphate (LFP), lithium cobalt oxide (LCO), or lithium nickel cobalt aluminum oxide (NCA); WO'465, Pgs. 6, 7).
However, as set forth in the rejection of claim 1, WO'465 does not explicitly disclose preparing the composition into a sheet during the mixing step (2), forming the electrode mixture obtained in (2) into a bulk shape (step (3)), and rolling the bulk-shape electrode mixture obtained in (3) into a sheet shape (step (4)) (WO'465, Pgs. 2, 9, 17). Furthermore, while WO'465 discloses positive electrode active materials generically, WO'465's working examples are directed to graphite anode compositions, and WO'465 does not explicitly demonstrate the dry processing of a positive electrode active material composition (WO'465, Pgs. 9, 10).
WO'718 discloses dry molding methods for manufacturing an electrode for an electrochemical element, such as a lithium ion secondary battery, from dry particulate electrode materials comprising an active material, a conductive material, and a fibrillizable polytetrafluoroethylene (PTFE) binder (WO'718, Pgs. 2, 5, 10, 11). Specifically, WO'718 teaches forming the electrode mixture into a bulk shape (step (3)) by extrusion molding (paste extrusion) into an extruded mass or by mold pressing, and subsequently rolling or post-pressing the bulk-shape electrode mixture into a sheet shape using a roll pressing process with two cylindrical rolls (step (4)) (WO'718, Pg. 10). Furthermore, to the extent that step (2) recites preparing the composition into a sheet by applying shear stress while mixing, WO'718 teaches that dry extrusion molding subjects the material to shear while forming it into an extruded film/sheet, which can be further rolled or post-pressed between rolls to achieve uniform thickness and high density (WO'718, Pg. 10). Additionally, KR'354 discloses a method of manufacturing a positive electrode for a lithium secondary battery comprising preparing an electrode composition by dry-mixing a positive electrode (cathode) active material, a conductive material, and a polytetrafluoroethylene (PTFE) binder without using a solvent (KR'354, Pgs. 1, 3, 5). Specifically, KR'354 explicitly exemplifies dry-mixing a positive electrode active material (such as
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WO'465, WO'718, and KR'354 are analogous arts because each reference is from the same field of endeavor, namely the manufacture of electrodes for lithium secondary batteries using non-aqueous electrolytes, and each reference is reasonably pertinent to the particular problem of dry-processing fibrillatable PTFE binder compositions with battery active materials into durable, uniform electrode layers without the use of liquid processing solvents (WO'465, Pgs. 2, 5–7; WO'718, Pgs. 2, 5, 10, 11; KR'354, Pgs. 1–3, 5).
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to combine the dry-compounded, active-material-free PTFE and conductive carbon binder composition and high-shear jet-milling process of WO'465 with the intermediate bulk shaping and rolling steps taught by WO'718, and further to incorporate a positive electrode active material (such as
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) into the dry electrode composition as taught by KR'354 and WO'465, in order to successfully manufacture high-loading, crack-free positive electrode sheets by solvent-free dry processing as taught by KR'354, while consolidating the sheared electrode mixture into a bulk shape to ensure continuous and uniform feeding into a roll press to obtain a high-density, defect-free electrode sheet as taught by WO'718 (WO'718, Pg. 10; KR'354, Pgs. 2, 3, 5; WO'465, Pgs. 2, 6, 7, 9).
Response to Arguments
Applicant’s arguments with respect to claims 1-10 have been considered but are moot because the new ground of rejection does not rely on the combination of references applied in the prior rejection of record for any teaching.
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JIMMY K VO whose telephone number is (571)272-3242. The examiner can normally be reached Monday - Friday, 8 am to 6 pm EST.
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/JIMMY VO/
Primary Examiner
Art Unit 1723
/JIMMY VO/Primary Examiner, Art Unit 1723
