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 .
DETAILED ACTION
This Office Action is in response to the communication filed on 1/2/26. Applicant’s arguments have been considered but are not found persuasive. Claims 1, 4-12 and 14 are pending. This Action is FINAL, as necessitated by amendment.
Claims Analysis
At least claim 1 recites a binder polymer comprising a first binder polymer and a second binder polymer. The claims may encompass an embodiment wherein the binder polymer may further comprise a third binder polymer. The claims further recite the first binder polymer consists of styrene-butadiene rubber and the second binder polymer comprises polytetrafluoroethylene.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1, 4-9, 12 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al., KR 2014-0008957 A in view of Chen US 2020/0052279 A1.
Kim teaches a negative electrode active material composition comprising a negative electrode active material, a conductive material and a binder wherein the binder is a mixture of a styrene-based binder and a fluoroethylene-based binder (abstract). Preferably the styrene-based binder is SBR and the fluoroethylene-based binder is PTFE. Examples 1-5 and Comparative Examples 1-2 disclose different weight ratios of the negative electrode active material composition and are shown by Table 1.
Specifically, the negative electrode active material slurry of Comparative Example 1 was prepared using 94% by weight of the active material, 2% by weight of the conductive material, 2% by weight of the binder and 2% by weight of the thickener. The negative electrode active material slurry of Comparative Example 2 was prepared using 93% by weight of the active material, 2% by weight of the conductive material, 3 wt% binder and 2 wt% thickener. The negative electrode active material slurries of Examples 1 to 5 were prepared in the same manner as in the Comparative Examples, except that SBR and PTFE were mixed as binders. Table 1 shows binder weight ratios for mixing SBR:PTFE of 97:3 (Example 1) and 90:10 (Example 2).
The negative electrode active material is applied to a negative electrode (current collector). The negative electrode active material may be a metal compound, a metal oxide compound, or a mixture thereof. The conductive material may be carbon black, carbon fiber, metal fiber, carbon fluoride, metal powder, zinc oxide or polyphenylene derivative.
Kim does not explicitly teach the current collector has a mesh structure. However, Chen teaches an energy storage electrode is formed by heat-pressing preformed electrode membranes into the pore structures of a metal mesh current collector (Example 3 teaches a copper mesh). The electrodes are utilized primarily for Li-ion batteries (abstract). The electrode membranes are inherently locked into the pore structures of the mesh by heat-pressing, forming an inherently integrated component that improves performance characteristics of the battery including higher energy and power densities, and structural flexibility in cell configuration designs [0006-0007]. The mesh electrode is essentially an electrode of metal mesh/wire reinforced ceramic/polymer composite, showing improved mechanical strength and increased electrode materials loading over conventional electrode using a metal foil current collector. The mesh wire diameter and mesh pore/opening size may range, for example, from 10 to 100 microns, whereas the thickness of the finished electrode is from 10 to 300 microns. In a particularly preferred embodiment, mesh wire diameter and mesh pore size are 25 microns and finished electrode thickness 75 microns [0017]. A metal mesh having dimensions (for example, mesh wire diameter and pore size) ranging from several microns to several hundred microns, is utilized as a current collector [0022]. The temperature for the heat-pressing may range from room temperature to 400° C., and the pressure from 0 to 65 psig [0018]. Any suitable Li-ion anode material may be used. Such materials in powder form may be mixed with a conductive additive and a polymer binder without presence of a solvent and pressed with or without heat, forming electrode membranes, a pair of which, sandwiching a mesh, may be pressed partially into the pores of the metal mesh under pressure and heat, forming mesh-based Li-ion anodes. The relative proportions of active material, conductive additive, and polymer binder may range, for example, from 50 wt % to 90 wt % of active material, and 0 wt % to 15 wt % of conductive additive, the balance being polymer binder [0025]. Polymer binders may include (PTFE) and (SBR). See also the Figures and [0027-0030]. Chen teaches the anode material of the lithium battery include graphite and silicon [0018].
One of skill in the art would have been motivated to use the current collector metal mesh of Chen for the negative electrode of Kim because Chen teaches the electrode active material layers are inherently locked into the pore structures of the mesh by heat-pressing, forming an inherently integrated component that improves performance characteristics of the battery including higher energy and power densities, and structural flexibility in cell configuration designs [0006-0007]. The negative active material composition of Kim falls within the relative proportions of the active material layer of Chen. Furthermore, Chen teaches any suitable Li-ion anode material may be used with the metal mesh current collector.
Kim does not explicitly teach the binder comprising SBR and PTFE has a thermal decomposition temperature ranging from 270-315°C. However, the invention as a whole would have been obvious to one having ordinary skill in the art at the time the invention was made because one of skill would have reasonably expected a polymer binder comprising 90-97 wt% SBR and 3-10 wt% PTFE to have a thermal decomposition temperature within the claimed range. One of skill in the art would have reasonably expected the same or similar binder polymers to have the same or similar properties (thermal decomposition temperature). Both Kim and the claimed invention recite a polymer binder of SBR:PTFE having a weight ratio of 90:10. Kim teaches the lithium secondary battery is a lithium secondary battery including a separator and an electrolyte interposed between the negative electrode and the positive electrode.
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Claims 1, 4-7, 9 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Gyun et al., KR 100739944 B1.
Gyun teaches an anode for a lithium secondary battery, which prevents an anode active material from being separated from an anode collector or from cracking, and solves the problem of a drop in binding force occurring when using styrene-butadiene rubber as a binder. The anode for a lithium secondary battery comprises: an anode collector; and an anode active material layer formed on at least one surface of the anode collector, wherein the anode active material layer comprises artificial graphite as an anode active material, styrene-butadiene rubber (SBR: first binder polymer) and polytetrafluoroethylene (PTFE: second binder polymer) as binders, and carboxymethyl cellulose (CMC) as a thickening agent, in a weight ratio of 95:2.4:0.6:2 (abstract). The anode collector may be a punching metal, foil, expanded metal, mesh metal, a nickel foil or a copper foil. The binder mixture of SBR and PTFE may comprise PTFE in an amount of 15-50 wt% (50-85 wt% SBR). A negative electrode active material slurry is applied to the negative electrode collector and then dried and rolled (line pressed) to form the negative electrode [0001]. The SBR (2.4 wt%) and PTFE (0.6 wt%) binders comprise a total of 3 wt% of the binder polymer in the anode active material layer. The specific example teaches a polymer binder weight ratio of SBR:PTFE of 80:20.
Gyun teaches the binder mixture of SBR and PTFE may comprise PTFE in an amount of 15-50 wt%. Thus, the invention as a whole would have been obvious to one having ordinary skill in the art because Gyun teaches the binder mixture of SBR and PTFE may comprise PTFE in an amount of 15%. Gyun teaches the claimed range with sufficient specificity as the end point of Gyun and the end point of the claimed binder ratio are the same. Gyun at least suggests the binder mixture of SBR and PTFE has a weight ratio of 85:15.
Gyun does not explicitly teach the binder comprising SBR and PTFE has a thermal decomposition temperature ranging from 270-315°C. However, the invention as a whole would have been obvious to one having ordinary skill in the art at the time the invention was made because one of skill would have reasonably expected a polymer binder comprising 50-85 wt% SBR and 15-50 wt% PTFE to have a thermal decomposition temperature within the claimed range. Gyun teaches if the weight percent of PTFE is too low, there is a problem with the flexibility and bending properties of the anode. On the other hand, if the weight percent of PTFE is too high, it is difficult to proceed with electrode slurry coating and subsequent pressing of the anode. Furthermore, a desorption phenomenon of the active material can occur. In addition, one of skill in the art would have found it obvious that the mesh structure is present in the electrode active material sheet as Gyun teaches an active material slurry is coated unto a mesh current collector and then pressed.
Regarding claims 4-7, Gyun teaches an anode for a lithium secondary battery comprising an anode collector and an anode active material layer formed on at least one surface of the anode collector. The anode active material layer comprises artificial graphite as an anode active material, styrene-butadiene rubber(SBR) and polytetrafluoroethylene(PTFE) as binders, and carboxymethyl cellulose as a thickening agent, wherein the binder is present in an amount of 3 wt% of the anode active material layer (abstract). The binder may comprises 85 wt% SBR and 15 wt% PTFE. The anode collector may be a copper mesh or nickel mesh.
Note Example 3 of the present specification teaches a binder polymer having a weight ratio of SBR:PTFE of 80:20 (thermal decomposition temperature: 284°C).
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Claim(s) 1, 4-9 and 12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Chen US 2020/0052279 A1 in view of Gyun et al., KR 100739944 B1.
Chen teaches an energy storage electrode is formed by heat-pressing preformed electrode membranes into the pore structures of a metal mesh current collector without use of any solvents. The electrodes are utilized primarily for Li-ion batteries (abstract). The electrode membranes are inherently locked into the pore structures of the mesh by heat-pressing, forming an inherently integrated component that improves performance characteristics of the battery including higher energy and power densities, and structural flexibility in cell configuration designs [0006-0007]. The mesh electrode is essentially an electrode of metal mesh/wire reinforced ceramic/polymer composite, showing improved mechanical strength and increased electrode materials loading over conventional electrode using a metal foil current collector. The mesh wire diameter and mesh pore/opening size may range, for example, from 10 to 100 microns, whereas the thickness of the finished electrode is from 10 to 300 microns. In a particularly preferred embodiment of the invention, mesh wire diameter and mesh pore size are 25 microns and finished electrode thickness 75 microns [0017]. A metal mesh having dimensions (for example, mesh wire diameter and pore size) ranging from several microns to several hundred microns, is utilized as a current collector [0022].
Polymer binders may include polyvinylidene fluoride (PVDF), ethylene-propylene diene (EPDM), carboxy methyl cellulose (CMC), polytetrafluoroethylene (PTFE) and sodium carboxymethyl cellulose (SBR). The temperature for the heat-pressing may range from room temperature to 400° C., and the pressure from 0 to 65 psig [0018]. Any suitable Li-ion anode material may be used, with graphite or Si as an example. Such materials in powder form may be mixed with a conductive additive and a polymer binder without presence of a solvent and pressed with or without heat, forming electrode membranes, a pair of which, sandwiching a mesh, may be pressed partially into the pores of the metal mesh under pressure and heat, forming mesh-based Li-ion anodes without using any solvents. The relative proportions of active material, conductive additive, and polymer binder may range, for example, from 50 wt % to 90 wt % of active material, and 0 wt % to 15 wt % of conductive additive, the balance being polymer binder [0025]. See also the Figures and [0027-0030].
Chen does not explicitly teach the polymer binder has a thermal decomposition temperature ranging from 270-315°C. However, Chen teaches the polymer binder includes SBR (first binder polymer) and/or PTFE (second binder polymer). Gyun teaches an anode for a lithium secondary battery comprising an anode collector and an anode active material layer formed on at least one surface of the anode collector. The anode active material layer comprises artificial graphite as an anode active material, styrene-butadiene rubber(SBR) and polytetrafluoroethylene(PTFE) as binders, and carboxymethyl cellulose as a thickening agent (abstract). The binder may comprises 85 wt% SBR and 15 wt% PTFE. One of skill in the art would have been motivated to use the polymer binder of Gyun for the polymer binder of Chen as Gyun teaches if the weight percent of PTFE is too low, there is a problem with the flexibility and bending properties of the anode. On the other hand, if the weight percent of PTFE is too high, it is difficult to proceed with electrode coating and subsequent pressing of the anode. Furthermore, a desorption phenomenon of the active material can occur. Gyun teaches an active material is coated unto a mesh current collector and then pressed. Chen teaches improving the structural flexibility of the electrode [0006-0007]. See full discussion of Gyun above regarding the claimed weight ratio of the first binder polymer and the second binder polymer.
Allowable Subject Matter
Claims 10-11 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. Claim 10 recites the electrode active material and the binder polymer are mixed to form “a granular composite” and then sieving “the granular composite”. Thus, the sieving step, to control particle size as described in the present specification, occurs after the electrode active material and binder polymer have already been mixed together.
Response to Arguments
Applicant's arguments filed 1/2/26 have been fully considered but they are not persuasive. To clarify the record, Table 1 of the specification was amended on 7/13/22 to delete Comparative Example 3 from Table 1. See the description of Comparative Example 3 at [121]-[123].
Applicant argues Gyun merely discloses SBR and PTFE in a weight ratio of 80:20, which is outside the claimed range. Examiner disagrees. Gyun is not limited to any specific embodiment disclosed by the reference. Gyun clearly teaches the binder mixture of SBR and PTFE may comprise PTFE in an amount of 15-50 wt% (50-85 wt% SBR). Gyun discloses a binder polymer comprising a first binder polymer consisting of SBR and a second binder polymer comprising PTFE in a weight ratio of 85:15.
Any evidence of unexpected results must distinguish the claimed invention over the prior art of record. Again, Gyun discloses a binder polymer comprising a first binder polymer consisting of SBR and a second binder polymer comprising PTFE in a weight ratio of 85:15. Therefore, with regards to at least claim 1, evidence of unexpected results has not been provided. Furthermore, Applicant does not address the teachings of Example 3 (SBR:PTFE=80:20; thermal decomposition temperature of 284°C) and the results for Example 3 shown in Table 2 of the present specification. Evidence of unexpected results has not been shown over Gyun and/or Example 3 of the present specification.
Example 1 of the present specification discloses a SBR:PTFE weight ratio of 90:10 and a thermal decomposition temperature of 297°C. This example is narrower in scope than pending claim 1. Example 2 (SBR:PTFE weight ratio of 95:5) clearly does not provide evidence of unexpected results as Table 2 shows Example 2 has 2/5 ignition events and Example 3 (SBR:PTFE weight ratio of 80:20) has 1/5 ignition events. Examiner notes claim 14 has not been rejected in view of Gyun.
Furthermore, Comparative Example 1 (100 wt% PTFE) and Comparative Example 2 (100 wt% SBR) of the present specification are clearly not representative of the cited prior art. Evidence of unexpected results must distinguish the claimed invention over the prior art of record.
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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/TRACY M DOVE/Primary Examiner, Art Unit 1725